Bug Summary

File:src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include/llvm/ADT/APSInt.h
Warning:line 22, column 22
Assigned value is garbage or undefined

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ExprConstant.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangAST/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangAST/obj/../include/clang/AST -I /usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangAST/../include -I /usr/src/gnu/usr.bin/clang/libclangAST/obj -I /usr/src/gnu/usr.bin/clang/libclangAST/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangAST/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp

1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the Expr constant evaluator.
10//
11// Constant expression evaluation produces four main results:
12//
13// * A success/failure flag indicating whether constant folding was successful.
14// This is the 'bool' return value used by most of the code in this file. A
15// 'false' return value indicates that constant folding has failed, and any
16// appropriate diagnostic has already been produced.
17//
18// * An evaluated result, valid only if constant folding has not failed.
19//
20// * A flag indicating if evaluation encountered (unevaluated) side-effects.
21// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
22// where it is possible to determine the evaluated result regardless.
23//
24// * A set of notes indicating why the evaluation was not a constant expression
25// (under the C++11 / C++1y rules only, at the moment), or, if folding failed
26// too, why the expression could not be folded.
27//
28// If we are checking for a potential constant expression, failure to constant
29// fold a potential constant sub-expression will be indicated by a 'false'
30// return value (the expression could not be folded) and no diagnostic (the
31// expression is not necessarily non-constant).
32//
33//===----------------------------------------------------------------------===//
34
35#include "Interp/Context.h"
36#include "Interp/Frame.h"
37#include "Interp/State.h"
38#include "clang/AST/APValue.h"
39#include "clang/AST/ASTContext.h"
40#include "clang/AST/ASTDiagnostic.h"
41#include "clang/AST/ASTLambda.h"
42#include "clang/AST/Attr.h"
43#include "clang/AST/CXXInheritance.h"
44#include "clang/AST/CharUnits.h"
45#include "clang/AST/CurrentSourceLocExprScope.h"
46#include "clang/AST/Expr.h"
47#include "clang/AST/OSLog.h"
48#include "clang/AST/OptionalDiagnostic.h"
49#include "clang/AST/RecordLayout.h"
50#include "clang/AST/StmtVisitor.h"
51#include "clang/AST/TypeLoc.h"
52#include "clang/Basic/Builtins.h"
53#include "clang/Basic/TargetInfo.h"
54#include "llvm/ADT/APFixedPoint.h"
55#include "llvm/ADT/Optional.h"
56#include "llvm/ADT/SmallBitVector.h"
57#include "llvm/Support/Debug.h"
58#include "llvm/Support/SaveAndRestore.h"
59#include "llvm/Support/raw_ostream.h"
60#include <cstring>
61#include <functional>
62
63#define DEBUG_TYPE"exprconstant" "exprconstant"
64
65using namespace clang;
66using llvm::APFixedPoint;
67using llvm::APInt;
68using llvm::APSInt;
69using llvm::APFloat;
70using llvm::FixedPointSemantics;
71using llvm::Optional;
72
73namespace {
74 struct LValue;
75 class CallStackFrame;
76 class EvalInfo;
77
78 using SourceLocExprScopeGuard =
79 CurrentSourceLocExprScope::SourceLocExprScopeGuard;
80
81 static QualType getType(APValue::LValueBase B) {
82 return B.getType();
83 }
84
85 /// Get an LValue path entry, which is known to not be an array index, as a
86 /// field declaration.
87 static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
88 return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer());
89 }
90 /// Get an LValue path entry, which is known to not be an array index, as a
91 /// base class declaration.
92 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
93 return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer());
94 }
95 /// Determine whether this LValue path entry for a base class names a virtual
96 /// base class.
97 static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
98 return E.getAsBaseOrMember().getInt();
99 }
100
101 /// Given an expression, determine the type used to store the result of
102 /// evaluating that expression.
103 static QualType getStorageType(const ASTContext &Ctx, const Expr *E) {
104 if (E->isPRValue())
105 return E->getType();
106 return Ctx.getLValueReferenceType(E->getType());
107 }
108
109 /// Given a CallExpr, try to get the alloc_size attribute. May return null.
110 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
111 if (const FunctionDecl *DirectCallee = CE->getDirectCallee())
112 return DirectCallee->getAttr<AllocSizeAttr>();
113 if (const Decl *IndirectCallee = CE->getCalleeDecl())
114 return IndirectCallee->getAttr<AllocSizeAttr>();
115 return nullptr;
116 }
117
118 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
119 /// This will look through a single cast.
120 ///
121 /// Returns null if we couldn't unwrap a function with alloc_size.
122 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
123 if (!E->getType()->isPointerType())
124 return nullptr;
125
126 E = E->IgnoreParens();
127 // If we're doing a variable assignment from e.g. malloc(N), there will
128 // probably be a cast of some kind. In exotic cases, we might also see a
129 // top-level ExprWithCleanups. Ignore them either way.
130 if (const auto *FE = dyn_cast<FullExpr>(E))
131 E = FE->getSubExpr()->IgnoreParens();
132
133 if (const auto *Cast = dyn_cast<CastExpr>(E))
134 E = Cast->getSubExpr()->IgnoreParens();
135
136 if (const auto *CE = dyn_cast<CallExpr>(E))
137 return getAllocSizeAttr(CE) ? CE : nullptr;
138 return nullptr;
139 }
140
141 /// Determines whether or not the given Base contains a call to a function
142 /// with the alloc_size attribute.
143 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
144 const auto *E = Base.dyn_cast<const Expr *>();
145 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
146 }
147
148 /// Determines whether the given kind of constant expression is only ever
149 /// used for name mangling. If so, it's permitted to reference things that we
150 /// can't generate code for (in particular, dllimported functions).
151 static bool isForManglingOnly(ConstantExprKind Kind) {
152 switch (Kind) {
153 case ConstantExprKind::Normal:
154 case ConstantExprKind::ClassTemplateArgument:
155 case ConstantExprKind::ImmediateInvocation:
156 // Note that non-type template arguments of class type are emitted as
157 // template parameter objects.
158 return false;
159
160 case ConstantExprKind::NonClassTemplateArgument:
161 return true;
162 }
163 llvm_unreachable("unknown ConstantExprKind")__builtin_unreachable();
164 }
165
166 static bool isTemplateArgument(ConstantExprKind Kind) {
167 switch (Kind) {
168 case ConstantExprKind::Normal:
169 case ConstantExprKind::ImmediateInvocation:
170 return false;
171
172 case ConstantExprKind::ClassTemplateArgument:
173 case ConstantExprKind::NonClassTemplateArgument:
174 return true;
175 }
176 llvm_unreachable("unknown ConstantExprKind")__builtin_unreachable();
177 }
178
179 /// The bound to claim that an array of unknown bound has.
180 /// The value in MostDerivedArraySize is undefined in this case. So, set it
181 /// to an arbitrary value that's likely to loudly break things if it's used.
182 static const uint64_t AssumedSizeForUnsizedArray =
183 std::numeric_limits<uint64_t>::max() / 2;
184
185 /// Determines if an LValue with the given LValueBase will have an unsized
186 /// array in its designator.
187 /// Find the path length and type of the most-derived subobject in the given
188 /// path, and find the size of the containing array, if any.
189 static unsigned
190 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
191 ArrayRef<APValue::LValuePathEntry> Path,
192 uint64_t &ArraySize, QualType &Type, bool &IsArray,
193 bool &FirstEntryIsUnsizedArray) {
194 // This only accepts LValueBases from APValues, and APValues don't support
195 // arrays that lack size info.
196 assert(!isBaseAnAllocSizeCall(Base) &&((void)0)
197 "Unsized arrays shouldn't appear here")((void)0);
198 unsigned MostDerivedLength = 0;
199 Type = getType(Base);
200
201 for (unsigned I = 0, N = Path.size(); I != N; ++I) {
202 if (Type->isArrayType()) {
203 const ArrayType *AT = Ctx.getAsArrayType(Type);
204 Type = AT->getElementType();
205 MostDerivedLength = I + 1;
206 IsArray = true;
207
208 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
209 ArraySize = CAT->getSize().getZExtValue();
210 } else {
211 assert(I == 0 && "unexpected unsized array designator")((void)0);
212 FirstEntryIsUnsizedArray = true;
213 ArraySize = AssumedSizeForUnsizedArray;
214 }
215 } else if (Type->isAnyComplexType()) {
216 const ComplexType *CT = Type->castAs<ComplexType>();
217 Type = CT->getElementType();
218 ArraySize = 2;
219 MostDerivedLength = I + 1;
220 IsArray = true;
221 } else if (const FieldDecl *FD = getAsField(Path[I])) {
222 Type = FD->getType();
223 ArraySize = 0;
224 MostDerivedLength = I + 1;
225 IsArray = false;
226 } else {
227 // Path[I] describes a base class.
228 ArraySize = 0;
229 IsArray = false;
230 }
231 }
232 return MostDerivedLength;
233 }
234
235 /// A path from a glvalue to a subobject of that glvalue.
236 struct SubobjectDesignator {
237 /// True if the subobject was named in a manner not supported by C++11. Such
238 /// lvalues can still be folded, but they are not core constant expressions
239 /// and we cannot perform lvalue-to-rvalue conversions on them.
240 unsigned Invalid : 1;
241
242 /// Is this a pointer one past the end of an object?
243 unsigned IsOnePastTheEnd : 1;
244
245 /// Indicator of whether the first entry is an unsized array.
246 unsigned FirstEntryIsAnUnsizedArray : 1;
247
248 /// Indicator of whether the most-derived object is an array element.
249 unsigned MostDerivedIsArrayElement : 1;
250
251 /// The length of the path to the most-derived object of which this is a
252 /// subobject.
253 unsigned MostDerivedPathLength : 28;
254
255 /// The size of the array of which the most-derived object is an element.
256 /// This will always be 0 if the most-derived object is not an array
257 /// element. 0 is not an indicator of whether or not the most-derived object
258 /// is an array, however, because 0-length arrays are allowed.
259 ///
260 /// If the current array is an unsized array, the value of this is
261 /// undefined.
262 uint64_t MostDerivedArraySize;
263
264 /// The type of the most derived object referred to by this address.
265 QualType MostDerivedType;
266
267 typedef APValue::LValuePathEntry PathEntry;
268
269 /// The entries on the path from the glvalue to the designated subobject.
270 SmallVector<PathEntry, 8> Entries;
271
272 SubobjectDesignator() : Invalid(true) {}
273
274 explicit SubobjectDesignator(QualType T)
275 : Invalid(false), IsOnePastTheEnd(false),
276 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
277 MostDerivedPathLength(0), MostDerivedArraySize(0),
278 MostDerivedType(T) {}
279
280 SubobjectDesignator(ASTContext &Ctx, const APValue &V)
281 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
282 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
283 MostDerivedPathLength(0), MostDerivedArraySize(0) {
284 assert(V.isLValue() && "Non-LValue used to make an LValue designator?")((void)0);
285 if (!Invalid) {
286 IsOnePastTheEnd = V.isLValueOnePastTheEnd();
287 ArrayRef<PathEntry> VEntries = V.getLValuePath();
288 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
289 if (V.getLValueBase()) {
290 bool IsArray = false;
291 bool FirstIsUnsizedArray = false;
292 MostDerivedPathLength = findMostDerivedSubobject(
293 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
294 MostDerivedType, IsArray, FirstIsUnsizedArray);
295 MostDerivedIsArrayElement = IsArray;
296 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
297 }
298 }
299 }
300
301 void truncate(ASTContext &Ctx, APValue::LValueBase Base,
302 unsigned NewLength) {
303 if (Invalid)
304 return;
305
306 assert(Base && "cannot truncate path for null pointer")((void)0);
307 assert(NewLength <= Entries.size() && "not a truncation")((void)0);
308
309 if (NewLength == Entries.size())
310 return;
311 Entries.resize(NewLength);
312
313 bool IsArray = false;
314 bool FirstIsUnsizedArray = false;
315 MostDerivedPathLength = findMostDerivedSubobject(
316 Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray,
317 FirstIsUnsizedArray);
318 MostDerivedIsArrayElement = IsArray;
319 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
320 }
321
322 void setInvalid() {
323 Invalid = true;
324 Entries.clear();
325 }
326
327 /// Determine whether the most derived subobject is an array without a
328 /// known bound.
329 bool isMostDerivedAnUnsizedArray() const {
330 assert(!Invalid && "Calling this makes no sense on invalid designators")((void)0);
331 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
332 }
333
334 /// Determine what the most derived array's size is. Results in an assertion
335 /// failure if the most derived array lacks a size.
336 uint64_t getMostDerivedArraySize() const {
337 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size")((void)0);
338 return MostDerivedArraySize;
339 }
340
341 /// Determine whether this is a one-past-the-end pointer.
342 bool isOnePastTheEnd() const {
343 assert(!Invalid)((void)0);
344 if (IsOnePastTheEnd)
345 return true;
346 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
347 Entries[MostDerivedPathLength - 1].getAsArrayIndex() ==
348 MostDerivedArraySize)
349 return true;
350 return false;
351 }
352
353 /// Get the range of valid index adjustments in the form
354 /// {maximum value that can be subtracted from this pointer,
355 /// maximum value that can be added to this pointer}
356 std::pair<uint64_t, uint64_t> validIndexAdjustments() {
357 if (Invalid || isMostDerivedAnUnsizedArray())
358 return {0, 0};
359
360 // [expr.add]p4: For the purposes of these operators, a pointer to a
361 // nonarray object behaves the same as a pointer to the first element of
362 // an array of length one with the type of the object as its element type.
363 bool IsArray = MostDerivedPathLength == Entries.size() &&
364 MostDerivedIsArrayElement;
365 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
366 : (uint64_t)IsOnePastTheEnd;
367 uint64_t ArraySize =
368 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
369 return {ArrayIndex, ArraySize - ArrayIndex};
370 }
371
372 /// Check that this refers to a valid subobject.
373 bool isValidSubobject() const {
374 if (Invalid)
375 return false;
376 return !isOnePastTheEnd();
377 }
378 /// Check that this refers to a valid subobject, and if not, produce a
379 /// relevant diagnostic and set the designator as invalid.
380 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
381
382 /// Get the type of the designated object.
383 QualType getType(ASTContext &Ctx) const {
384 assert(!Invalid && "invalid designator has no subobject type")((void)0);
385 return MostDerivedPathLength == Entries.size()
386 ? MostDerivedType
387 : Ctx.getRecordType(getAsBaseClass(Entries.back()));
388 }
389
390 /// Update this designator to refer to the first element within this array.
391 void addArrayUnchecked(const ConstantArrayType *CAT) {
392 Entries.push_back(PathEntry::ArrayIndex(0));
393
394 // This is a most-derived object.
395 MostDerivedType = CAT->getElementType();
396 MostDerivedIsArrayElement = true;
397 MostDerivedArraySize = CAT->getSize().getZExtValue();
398 MostDerivedPathLength = Entries.size();
399 }
400 /// Update this designator to refer to the first element within the array of
401 /// elements of type T. This is an array of unknown size.
402 void addUnsizedArrayUnchecked(QualType ElemTy) {
403 Entries.push_back(PathEntry::ArrayIndex(0));
404
405 MostDerivedType = ElemTy;
406 MostDerivedIsArrayElement = true;
407 // The value in MostDerivedArraySize is undefined in this case. So, set it
408 // to an arbitrary value that's likely to loudly break things if it's
409 // used.
410 MostDerivedArraySize = AssumedSizeForUnsizedArray;
411 MostDerivedPathLength = Entries.size();
412 }
413 /// Update this designator to refer to the given base or member of this
414 /// object.
415 void addDeclUnchecked(const Decl *D, bool Virtual = false) {
416 Entries.push_back(APValue::BaseOrMemberType(D, Virtual));
417
418 // If this isn't a base class, it's a new most-derived object.
419 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
420 MostDerivedType = FD->getType();
421 MostDerivedIsArrayElement = false;
422 MostDerivedArraySize = 0;
423 MostDerivedPathLength = Entries.size();
424 }
425 }
426 /// Update this designator to refer to the given complex component.
427 void addComplexUnchecked(QualType EltTy, bool Imag) {
428 Entries.push_back(PathEntry::ArrayIndex(Imag));
429
430 // This is technically a most-derived object, though in practice this
431 // is unlikely to matter.
432 MostDerivedType = EltTy;
433 MostDerivedIsArrayElement = true;
434 MostDerivedArraySize = 2;
435 MostDerivedPathLength = Entries.size();
436 }
437 void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E);
438 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
439 const APSInt &N);
440 /// Add N to the address of this subobject.
441 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
442 if (Invalid || !N) return;
443 uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
444 if (isMostDerivedAnUnsizedArray()) {
445 diagnoseUnsizedArrayPointerArithmetic(Info, E);
446 // Can't verify -- trust that the user is doing the right thing (or if
447 // not, trust that the caller will catch the bad behavior).
448 // FIXME: Should we reject if this overflows, at least?
449 Entries.back() = PathEntry::ArrayIndex(
450 Entries.back().getAsArrayIndex() + TruncatedN);
451 return;
452 }
453
454 // [expr.add]p4: For the purposes of these operators, a pointer to a
455 // nonarray object behaves the same as a pointer to the first element of
456 // an array of length one with the type of the object as its element type.
457 bool IsArray = MostDerivedPathLength == Entries.size() &&
458 MostDerivedIsArrayElement;
459 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
460 : (uint64_t)IsOnePastTheEnd;
461 uint64_t ArraySize =
462 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
463
464 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
465 // Calculate the actual index in a wide enough type, so we can include
466 // it in the note.
467 N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
468 (llvm::APInt&)N += ArrayIndex;
469 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index")((void)0);
470 diagnosePointerArithmetic(Info, E, N);
471 setInvalid();
472 return;
473 }
474
475 ArrayIndex += TruncatedN;
476 assert(ArrayIndex <= ArraySize &&((void)0)
477 "bounds check succeeded for out-of-bounds index")((void)0);
478
479 if (IsArray)
480 Entries.back() = PathEntry::ArrayIndex(ArrayIndex);
481 else
482 IsOnePastTheEnd = (ArrayIndex != 0);
483 }
484 };
485
486 /// A scope at the end of which an object can need to be destroyed.
487 enum class ScopeKind {
488 Block,
489 FullExpression,
490 Call
491 };
492
493 /// A reference to a particular call and its arguments.
494 struct CallRef {
495 CallRef() : OrigCallee(), CallIndex(0), Version() {}
496 CallRef(const FunctionDecl *Callee, unsigned CallIndex, unsigned Version)
497 : OrigCallee(Callee), CallIndex(CallIndex), Version(Version) {}
498
499 explicit operator bool() const { return OrigCallee; }
500
501 /// Get the parameter that the caller initialized, corresponding to the
502 /// given parameter in the callee.
503 const ParmVarDecl *getOrigParam(const ParmVarDecl *PVD) const {
504 return OrigCallee ? OrigCallee->getParamDecl(PVD->getFunctionScopeIndex())
505 : PVD;
506 }
507
508 /// The callee at the point where the arguments were evaluated. This might
509 /// be different from the actual callee (a different redeclaration, or a
510 /// virtual override), but this function's parameters are the ones that
511 /// appear in the parameter map.
512 const FunctionDecl *OrigCallee;
513 /// The call index of the frame that holds the argument values.
514 unsigned CallIndex;
515 /// The version of the parameters corresponding to this call.
516 unsigned Version;
517 };
518
519 /// A stack frame in the constexpr call stack.
520 class CallStackFrame : public interp::Frame {
521 public:
522 EvalInfo &Info;
523
524 /// Parent - The caller of this stack frame.
525 CallStackFrame *Caller;
526
527 /// Callee - The function which was called.
528 const FunctionDecl *Callee;
529
530 /// This - The binding for the this pointer in this call, if any.
531 const LValue *This;
532
533 /// Information on how to find the arguments to this call. Our arguments
534 /// are stored in our parent's CallStackFrame, using the ParmVarDecl* as a
535 /// key and this value as the version.
536 CallRef Arguments;
537
538 /// Source location information about the default argument or default
539 /// initializer expression we're evaluating, if any.
540 CurrentSourceLocExprScope CurSourceLocExprScope;
541
542 // Note that we intentionally use std::map here so that references to
543 // values are stable.
544 typedef std::pair<const void *, unsigned> MapKeyTy;
545 typedef std::map<MapKeyTy, APValue> MapTy;
546 /// Temporaries - Temporary lvalues materialized within this stack frame.
547 MapTy Temporaries;
548
549 /// CallLoc - The location of the call expression for this call.
550 SourceLocation CallLoc;
551
552 /// Index - The call index of this call.
553 unsigned Index;
554
555 /// The stack of integers for tracking version numbers for temporaries.
556 SmallVector<unsigned, 2> TempVersionStack = {1};
557 unsigned CurTempVersion = TempVersionStack.back();
558
559 unsigned getTempVersion() const { return TempVersionStack.back(); }
560
561 void pushTempVersion() {
562 TempVersionStack.push_back(++CurTempVersion);
563 }
564
565 void popTempVersion() {
566 TempVersionStack.pop_back();
567 }
568
569 CallRef createCall(const FunctionDecl *Callee) {
570 return {Callee, Index, ++CurTempVersion};
571 }
572
573 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
574 // on the overall stack usage of deeply-recursing constexpr evaluations.
575 // (We should cache this map rather than recomputing it repeatedly.)
576 // But let's try this and see how it goes; we can look into caching the map
577 // as a later change.
578
579 /// LambdaCaptureFields - Mapping from captured variables/this to
580 /// corresponding data members in the closure class.
581 llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields;
582 FieldDecl *LambdaThisCaptureField;
583
584 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
585 const FunctionDecl *Callee, const LValue *This,
586 CallRef Arguments);
587 ~CallStackFrame();
588
589 // Return the temporary for Key whose version number is Version.
590 APValue *getTemporary(const void *Key, unsigned Version) {
591 MapKeyTy KV(Key, Version);
592 auto LB = Temporaries.lower_bound(KV);
593 if (LB != Temporaries.end() && LB->first == KV)
594 return &LB->second;
595 // Pair (Key,Version) wasn't found in the map. Check that no elements
596 // in the map have 'Key' as their key.
597 assert((LB == Temporaries.end() || LB->first.first != Key) &&((void)0)
598 (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) &&((void)0)
599 "Element with key 'Key' found in map")((void)0);
600 return nullptr;
601 }
602
603 // Return the current temporary for Key in the map.
604 APValue *getCurrentTemporary(const void *Key) {
605 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX(2147483647 *2U +1U)));
606 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
607 return &std::prev(UB)->second;
608 return nullptr;
609 }
610
611 // Return the version number of the current temporary for Key.
612 unsigned getCurrentTemporaryVersion(const void *Key) const {
613 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX(2147483647 *2U +1U)));
614 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
615 return std::prev(UB)->first.second;
616 return 0;
617 }
618
619 /// Allocate storage for an object of type T in this stack frame.
620 /// Populates LV with a handle to the created object. Key identifies
621 /// the temporary within the stack frame, and must not be reused without
622 /// bumping the temporary version number.
623 template<typename KeyT>
624 APValue &createTemporary(const KeyT *Key, QualType T,
625 ScopeKind Scope, LValue &LV);
626
627 /// Allocate storage for a parameter of a function call made in this frame.
628 APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV);
629
630 void describe(llvm::raw_ostream &OS) override;
631
632 Frame *getCaller() const override { return Caller; }
633 SourceLocation getCallLocation() const override { return CallLoc; }
634 const FunctionDecl *getCallee() const override { return Callee; }
635
636 bool isStdFunction() const {
637 for (const DeclContext *DC = Callee; DC; DC = DC->getParent())
638 if (DC->isStdNamespace())
639 return true;
640 return false;
641 }
642
643 private:
644 APValue &createLocal(APValue::LValueBase Base, const void *Key, QualType T,
645 ScopeKind Scope);
646 };
647
648 /// Temporarily override 'this'.
649 class ThisOverrideRAII {
650 public:
651 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
652 : Frame(Frame), OldThis(Frame.This) {
653 if (Enable)
654 Frame.This = NewThis;
655 }
656 ~ThisOverrideRAII() {
657 Frame.This = OldThis;
658 }
659 private:
660 CallStackFrame &Frame;
661 const LValue *OldThis;
662 };
663}
664
665static bool HandleDestruction(EvalInfo &Info, const Expr *E,
666 const LValue &This, QualType ThisType);
667static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
668 APValue::LValueBase LVBase, APValue &Value,
669 QualType T);
670
671namespace {
672 /// A cleanup, and a flag indicating whether it is lifetime-extended.
673 class Cleanup {
674 llvm::PointerIntPair<APValue*, 2, ScopeKind> Value;
675 APValue::LValueBase Base;
676 QualType T;
677
678 public:
679 Cleanup(APValue *Val, APValue::LValueBase Base, QualType T,
680 ScopeKind Scope)
681 : Value(Val, Scope), Base(Base), T(T) {}
682
683 /// Determine whether this cleanup should be performed at the end of the
684 /// given kind of scope.
685 bool isDestroyedAtEndOf(ScopeKind K) const {
686 return (int)Value.getInt() >= (int)K;
687 }
688 bool endLifetime(EvalInfo &Info, bool RunDestructors) {
689 if (RunDestructors) {
690 SourceLocation Loc;
691 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
692 Loc = VD->getLocation();
693 else if (const Expr *E = Base.dyn_cast<const Expr*>())
694 Loc = E->getExprLoc();
695 return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T);
696 }
697 *Value.getPointer() = APValue();
698 return true;
699 }
700
701 bool hasSideEffect() {
702 return T.isDestructedType();
703 }
704 };
705
706 /// A reference to an object whose construction we are currently evaluating.
707 struct ObjectUnderConstruction {
708 APValue::LValueBase Base;
709 ArrayRef<APValue::LValuePathEntry> Path;
710 friend bool operator==(const ObjectUnderConstruction &LHS,
711 const ObjectUnderConstruction &RHS) {
712 return LHS.Base == RHS.Base && LHS.Path == RHS.Path;
713 }
714 friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) {
715 return llvm::hash_combine(Obj.Base, Obj.Path);
716 }
717 };
718 enum class ConstructionPhase {
719 None,
720 Bases,
721 AfterBases,
722 AfterFields,
723 Destroying,
724 DestroyingBases
725 };
726}
727
728namespace llvm {
729template<> struct DenseMapInfo<ObjectUnderConstruction> {
730 using Base = DenseMapInfo<APValue::LValueBase>;
731 static ObjectUnderConstruction getEmptyKey() {
732 return {Base::getEmptyKey(), {}}; }
733 static ObjectUnderConstruction getTombstoneKey() {
734 return {Base::getTombstoneKey(), {}};
735 }
736 static unsigned getHashValue(const ObjectUnderConstruction &Object) {
737 return hash_value(Object);
738 }
739 static bool isEqual(const ObjectUnderConstruction &LHS,
740 const ObjectUnderConstruction &RHS) {
741 return LHS == RHS;
742 }
743};
744}
745
746namespace {
747 /// A dynamically-allocated heap object.
748 struct DynAlloc {
749 /// The value of this heap-allocated object.
750 APValue Value;
751 /// The allocating expression; used for diagnostics. Either a CXXNewExpr
752 /// or a CallExpr (the latter is for direct calls to operator new inside
753 /// std::allocator<T>::allocate).
754 const Expr *AllocExpr = nullptr;
755
756 enum Kind {
757 New,
758 ArrayNew,
759 StdAllocator
760 };
761
762 /// Get the kind of the allocation. This must match between allocation
763 /// and deallocation.
764 Kind getKind() const {
765 if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr))
766 return NE->isArray() ? ArrayNew : New;
767 assert(isa<CallExpr>(AllocExpr))((void)0);
768 return StdAllocator;
769 }
770 };
771
772 struct DynAllocOrder {
773 bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const {
774 return L.getIndex() < R.getIndex();
775 }
776 };
777
778 /// EvalInfo - This is a private struct used by the evaluator to capture
779 /// information about a subexpression as it is folded. It retains information
780 /// about the AST context, but also maintains information about the folded
781 /// expression.
782 ///
783 /// If an expression could be evaluated, it is still possible it is not a C
784 /// "integer constant expression" or constant expression. If not, this struct
785 /// captures information about how and why not.
786 ///
787 /// One bit of information passed *into* the request for constant folding
788 /// indicates whether the subexpression is "evaluated" or not according to C
789 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
790 /// evaluate the expression regardless of what the RHS is, but C only allows
791 /// certain things in certain situations.
792 class EvalInfo : public interp::State {
793 public:
794 ASTContext &Ctx;
795
796 /// EvalStatus - Contains information about the evaluation.
797 Expr::EvalStatus &EvalStatus;
798
799 /// CurrentCall - The top of the constexpr call stack.
800 CallStackFrame *CurrentCall;
801
802 /// CallStackDepth - The number of calls in the call stack right now.
803 unsigned CallStackDepth;
804
805 /// NextCallIndex - The next call index to assign.
806 unsigned NextCallIndex;
807
808 /// StepsLeft - The remaining number of evaluation steps we're permitted
809 /// to perform. This is essentially a limit for the number of statements
810 /// we will evaluate.
811 unsigned StepsLeft;
812
813 /// Enable the experimental new constant interpreter. If an expression is
814 /// not supported by the interpreter, an error is triggered.
815 bool EnableNewConstInterp;
816
817 /// BottomFrame - The frame in which evaluation started. This must be
818 /// initialized after CurrentCall and CallStackDepth.
819 CallStackFrame BottomFrame;
820
821 /// A stack of values whose lifetimes end at the end of some surrounding
822 /// evaluation frame.
823 llvm::SmallVector<Cleanup, 16> CleanupStack;
824
825 /// EvaluatingDecl - This is the declaration whose initializer is being
826 /// evaluated, if any.
827 APValue::LValueBase EvaluatingDecl;
828
829 enum class EvaluatingDeclKind {
830 None,
831 /// We're evaluating the construction of EvaluatingDecl.
832 Ctor,
833 /// We're evaluating the destruction of EvaluatingDecl.
834 Dtor,
835 };
836 EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None;
837
838 /// EvaluatingDeclValue - This is the value being constructed for the
839 /// declaration whose initializer is being evaluated, if any.
840 APValue *EvaluatingDeclValue;
841
842 /// Set of objects that are currently being constructed.
843 llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase>
844 ObjectsUnderConstruction;
845
846 /// Current heap allocations, along with the location where each was
847 /// allocated. We use std::map here because we need stable addresses
848 /// for the stored APValues.
849 std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs;
850
851 /// The number of heap allocations performed so far in this evaluation.
852 unsigned NumHeapAllocs = 0;
853
854 struct EvaluatingConstructorRAII {
855 EvalInfo &EI;
856 ObjectUnderConstruction Object;
857 bool DidInsert;
858 EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object,
859 bool HasBases)
860 : EI(EI), Object(Object) {
861 DidInsert =
862 EI.ObjectsUnderConstruction
863 .insert({Object, HasBases ? ConstructionPhase::Bases
864 : ConstructionPhase::AfterBases})
865 .second;
866 }
867 void finishedConstructingBases() {
868 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases;
869 }
870 void finishedConstructingFields() {
871 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields;
872 }
873 ~EvaluatingConstructorRAII() {
874 if (DidInsert) EI.ObjectsUnderConstruction.erase(Object);
875 }
876 };
877
878 struct EvaluatingDestructorRAII {
879 EvalInfo &EI;
880 ObjectUnderConstruction Object;
881 bool DidInsert;
882 EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object)
883 : EI(EI), Object(Object) {
884 DidInsert = EI.ObjectsUnderConstruction
885 .insert({Object, ConstructionPhase::Destroying})
886 .second;
887 }
888 void startedDestroyingBases() {
889 EI.ObjectsUnderConstruction[Object] =
890 ConstructionPhase::DestroyingBases;
891 }
892 ~EvaluatingDestructorRAII() {
893 if (DidInsert)
894 EI.ObjectsUnderConstruction.erase(Object);
895 }
896 };
897
898 ConstructionPhase
899 isEvaluatingCtorDtor(APValue::LValueBase Base,
900 ArrayRef<APValue::LValuePathEntry> Path) {
901 return ObjectsUnderConstruction.lookup({Base, Path});
902 }
903
904 /// If we're currently speculatively evaluating, the outermost call stack
905 /// depth at which we can mutate state, otherwise 0.
906 unsigned SpeculativeEvaluationDepth = 0;
907
908 /// The current array initialization index, if we're performing array
909 /// initialization.
910 uint64_t ArrayInitIndex = -1;
911
912 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
913 /// notes attached to it will also be stored, otherwise they will not be.
914 bool HasActiveDiagnostic;
915
916 /// Have we emitted a diagnostic explaining why we couldn't constant
917 /// fold (not just why it's not strictly a constant expression)?
918 bool HasFoldFailureDiagnostic;
919
920 /// Whether or not we're in a context where the front end requires a
921 /// constant value.
922 bool InConstantContext;
923
924 /// Whether we're checking that an expression is a potential constant
925 /// expression. If so, do not fail on constructs that could become constant
926 /// later on (such as a use of an undefined global).
927 bool CheckingPotentialConstantExpression = false;
928
929 /// Whether we're checking for an expression that has undefined behavior.
930 /// If so, we will produce warnings if we encounter an operation that is
931 /// always undefined.
932 ///
933 /// Note that we still need to evaluate the expression normally when this
934 /// is set; this is used when evaluating ICEs in C.
935 bool CheckingForUndefinedBehavior = false;
936
937 enum EvaluationMode {
938 /// Evaluate as a constant expression. Stop if we find that the expression
939 /// is not a constant expression.
940 EM_ConstantExpression,
941
942 /// Evaluate as a constant expression. Stop if we find that the expression
943 /// is not a constant expression. Some expressions can be retried in the
944 /// optimizer if we don't constant fold them here, but in an unevaluated
945 /// context we try to fold them immediately since the optimizer never
946 /// gets a chance to look at it.
947 EM_ConstantExpressionUnevaluated,
948
949 /// Fold the expression to a constant. Stop if we hit a side-effect that
950 /// we can't model.
951 EM_ConstantFold,
952
953 /// Evaluate in any way we know how. Don't worry about side-effects that
954 /// can't be modeled.
955 EM_IgnoreSideEffects,
956 } EvalMode;
957
958 /// Are we checking whether the expression is a potential constant
959 /// expression?
960 bool checkingPotentialConstantExpression() const override {
961 return CheckingPotentialConstantExpression;
962 }
963
964 /// Are we checking an expression for overflow?
965 // FIXME: We should check for any kind of undefined or suspicious behavior
966 // in such constructs, not just overflow.
967 bool checkingForUndefinedBehavior() const override {
968 return CheckingForUndefinedBehavior;
969 }
970
971 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
972 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
973 CallStackDepth(0), NextCallIndex(1),
974 StepsLeft(C.getLangOpts().ConstexprStepLimit),
975 EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp),
976 BottomFrame(*this, SourceLocation(), nullptr, nullptr, CallRef()),
977 EvaluatingDecl((const ValueDecl *)nullptr),
978 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
979 HasFoldFailureDiagnostic(false), InConstantContext(false),
980 EvalMode(Mode) {}
981
982 ~EvalInfo() {
983 discardCleanups();
984 }
985
986 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value,
987 EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) {
988 EvaluatingDecl = Base;
989 IsEvaluatingDecl = EDK;
990 EvaluatingDeclValue = &Value;
991 }
992
993 bool CheckCallLimit(SourceLocation Loc) {
994 // Don't perform any constexpr calls (other than the call we're checking)
995 // when checking a potential constant expression.
996 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
997 return false;
998 if (NextCallIndex == 0) {
999 // NextCallIndex has wrapped around.
1000 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
1001 return false;
1002 }
1003 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
1004 return true;
1005 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
1006 << getLangOpts().ConstexprCallDepth;
1007 return false;
1008 }
1009
1010 std::pair<CallStackFrame *, unsigned>
1011 getCallFrameAndDepth(unsigned CallIndex) {
1012 assert(CallIndex && "no call index in getCallFrameAndDepth")((void)0);
1013 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
1014 // be null in this loop.
1015 unsigned Depth = CallStackDepth;
1016 CallStackFrame *Frame = CurrentCall;
1017 while (Frame->Index > CallIndex) {
1018 Frame = Frame->Caller;
1019 --Depth;
1020 }
1021 if (Frame->Index == CallIndex)
1022 return {Frame, Depth};
1023 return {nullptr, 0};
1024 }
1025
1026 bool nextStep(const Stmt *S) {
1027 if (!StepsLeft) {
1028 FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded);
1029 return false;
1030 }
1031 --StepsLeft;
1032 return true;
1033 }
1034
1035 APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV);
1036
1037 Optional<DynAlloc*> lookupDynamicAlloc(DynamicAllocLValue DA) {
1038 Optional<DynAlloc*> Result;
1039 auto It = HeapAllocs.find(DA);
1040 if (It != HeapAllocs.end())
1041 Result = &It->second;
1042 return Result;
1043 }
1044
1045 /// Get the allocated storage for the given parameter of the given call.
1046 APValue *getParamSlot(CallRef Call, const ParmVarDecl *PVD) {
1047 CallStackFrame *Frame = getCallFrameAndDepth(Call.CallIndex).first;
1048 return Frame ? Frame->getTemporary(Call.getOrigParam(PVD), Call.Version)
1049 : nullptr;
1050 }
1051
1052 /// Information about a stack frame for std::allocator<T>::[de]allocate.
1053 struct StdAllocatorCaller {
1054 unsigned FrameIndex;
1055 QualType ElemType;
1056 explicit operator bool() const { return FrameIndex != 0; };
1057 };
1058
1059 StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const {
1060 for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame;
1061 Call = Call->Caller) {
1062 const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee);
1063 if (!MD)
1064 continue;
1065 const IdentifierInfo *FnII = MD->getIdentifier();
1066 if (!FnII || !FnII->isStr(FnName))
1067 continue;
1068
1069 const auto *CTSD =
1070 dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent());
1071 if (!CTSD)
1072 continue;
1073
1074 const IdentifierInfo *ClassII = CTSD->getIdentifier();
1075 const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
1076 if (CTSD->isInStdNamespace() && ClassII &&
1077 ClassII->isStr("allocator") && TAL.size() >= 1 &&
1078 TAL[0].getKind() == TemplateArgument::Type)
1079 return {Call->Index, TAL[0].getAsType()};
1080 }
1081
1082 return {};
1083 }
1084
1085 void performLifetimeExtension() {
1086 // Disable the cleanups for lifetime-extended temporaries.
1087 CleanupStack.erase(std::remove_if(CleanupStack.begin(),
1088 CleanupStack.end(),
1089 [](Cleanup &C) {
1090 return !C.isDestroyedAtEndOf(
1091 ScopeKind::FullExpression);
1092 }),
1093 CleanupStack.end());
1094 }
1095
1096 /// Throw away any remaining cleanups at the end of evaluation. If any
1097 /// cleanups would have had a side-effect, note that as an unmodeled
1098 /// side-effect and return false. Otherwise, return true.
1099 bool discardCleanups() {
1100 for (Cleanup &C : CleanupStack) {
1101 if (C.hasSideEffect() && !noteSideEffect()) {
1102 CleanupStack.clear();
1103 return false;
1104 }
1105 }
1106 CleanupStack.clear();
1107 return true;
1108 }
1109
1110 private:
1111 interp::Frame *getCurrentFrame() override { return CurrentCall; }
1112 const interp::Frame *getBottomFrame() const override { return &BottomFrame; }
1113
1114 bool hasActiveDiagnostic() override { return HasActiveDiagnostic; }
1115 void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; }
1116
1117 void setFoldFailureDiagnostic(bool Flag) override {
1118 HasFoldFailureDiagnostic = Flag;
1119 }
1120
1121 Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; }
1122
1123 ASTContext &getCtx() const override { return Ctx; }
1124
1125 // If we have a prior diagnostic, it will be noting that the expression
1126 // isn't a constant expression. This diagnostic is more important,
1127 // unless we require this evaluation to produce a constant expression.
1128 //
1129 // FIXME: We might want to show both diagnostics to the user in
1130 // EM_ConstantFold mode.
1131 bool hasPriorDiagnostic() override {
1132 if (!EvalStatus.Diag->empty()) {
1133 switch (EvalMode) {
1134 case EM_ConstantFold:
1135 case EM_IgnoreSideEffects:
1136 if (!HasFoldFailureDiagnostic)
1137 break;
1138 // We've already failed to fold something. Keep that diagnostic.
1139 LLVM_FALLTHROUGH[[gnu::fallthrough]];
1140 case EM_ConstantExpression:
1141 case EM_ConstantExpressionUnevaluated:
1142 setActiveDiagnostic(false);
1143 return true;
1144 }
1145 }
1146 return false;
1147 }
1148
1149 unsigned getCallStackDepth() override { return CallStackDepth; }
1150
1151 public:
1152 /// Should we continue evaluation after encountering a side-effect that we
1153 /// couldn't model?
1154 bool keepEvaluatingAfterSideEffect() {
1155 switch (EvalMode) {
1156 case EM_IgnoreSideEffects:
1157 return true;
1158
1159 case EM_ConstantExpression:
1160 case EM_ConstantExpressionUnevaluated:
1161 case EM_ConstantFold:
1162 // By default, assume any side effect might be valid in some other
1163 // evaluation of this expression from a different context.
1164 return checkingPotentialConstantExpression() ||
1165 checkingForUndefinedBehavior();
1166 }
1167 llvm_unreachable("Missed EvalMode case")__builtin_unreachable();
1168 }
1169
1170 /// Note that we have had a side-effect, and determine whether we should
1171 /// keep evaluating.
1172 bool noteSideEffect() {
1173 EvalStatus.HasSideEffects = true;
1174 return keepEvaluatingAfterSideEffect();
1175 }
1176
1177 /// Should we continue evaluation after encountering undefined behavior?
1178 bool keepEvaluatingAfterUndefinedBehavior() {
1179 switch (EvalMode) {
1180 case EM_IgnoreSideEffects:
1181 case EM_ConstantFold:
1182 return true;
1183
1184 case EM_ConstantExpression:
1185 case EM_ConstantExpressionUnevaluated:
1186 return checkingForUndefinedBehavior();
1187 }
1188 llvm_unreachable("Missed EvalMode case")__builtin_unreachable();
1189 }
1190
1191 /// Note that we hit something that was technically undefined behavior, but
1192 /// that we can evaluate past it (such as signed overflow or floating-point
1193 /// division by zero.)
1194 bool noteUndefinedBehavior() override {
1195 EvalStatus.HasUndefinedBehavior = true;
1196 return keepEvaluatingAfterUndefinedBehavior();
1197 }
1198
1199 /// Should we continue evaluation as much as possible after encountering a
1200 /// construct which can't be reduced to a value?
1201 bool keepEvaluatingAfterFailure() const override {
1202 if (!StepsLeft)
1203 return false;
1204
1205 switch (EvalMode) {
1206 case EM_ConstantExpression:
1207 case EM_ConstantExpressionUnevaluated:
1208 case EM_ConstantFold:
1209 case EM_IgnoreSideEffects:
1210 return checkingPotentialConstantExpression() ||
1211 checkingForUndefinedBehavior();
1212 }
1213 llvm_unreachable("Missed EvalMode case")__builtin_unreachable();
1214 }
1215
1216 /// Notes that we failed to evaluate an expression that other expressions
1217 /// directly depend on, and determine if we should keep evaluating. This
1218 /// should only be called if we actually intend to keep evaluating.
1219 ///
1220 /// Call noteSideEffect() instead if we may be able to ignore the value that
1221 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
1222 ///
1223 /// (Foo(), 1) // use noteSideEffect
1224 /// (Foo() || true) // use noteSideEffect
1225 /// Foo() + 1 // use noteFailure
1226 LLVM_NODISCARD[[clang::warn_unused_result]] bool noteFailure() {
1227 // Failure when evaluating some expression often means there is some
1228 // subexpression whose evaluation was skipped. Therefore, (because we
1229 // don't track whether we skipped an expression when unwinding after an
1230 // evaluation failure) every evaluation failure that bubbles up from a
1231 // subexpression implies that a side-effect has potentially happened. We
1232 // skip setting the HasSideEffects flag to true until we decide to
1233 // continue evaluating after that point, which happens here.
1234 bool KeepGoing = keepEvaluatingAfterFailure();
1235 EvalStatus.HasSideEffects |= KeepGoing;
1236 return KeepGoing;
1237 }
1238
1239 class ArrayInitLoopIndex {
1240 EvalInfo &Info;
1241 uint64_t OuterIndex;
1242
1243 public:
1244 ArrayInitLoopIndex(EvalInfo &Info)
1245 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
1246 Info.ArrayInitIndex = 0;
1247 }
1248 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
1249
1250 operator uint64_t&() { return Info.ArrayInitIndex; }
1251 };
1252 };
1253
1254 /// Object used to treat all foldable expressions as constant expressions.
1255 struct FoldConstant {
1256 EvalInfo &Info;
1257 bool Enabled;
1258 bool HadNoPriorDiags;
1259 EvalInfo::EvaluationMode OldMode;
1260
1261 explicit FoldConstant(EvalInfo &Info, bool Enabled)
1262 : Info(Info),
1263 Enabled(Enabled),
1264 HadNoPriorDiags(Info.EvalStatus.Diag &&
1265 Info.EvalStatus.Diag->empty() &&
1266 !Info.EvalStatus.HasSideEffects),
1267 OldMode(Info.EvalMode) {
1268 if (Enabled)
1269 Info.EvalMode = EvalInfo::EM_ConstantFold;
1270 }
1271 void keepDiagnostics() { Enabled = false; }
1272 ~FoldConstant() {
1273 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
1274 !Info.EvalStatus.HasSideEffects)
1275 Info.EvalStatus.Diag->clear();
1276 Info.EvalMode = OldMode;
1277 }
1278 };
1279
1280 /// RAII object used to set the current evaluation mode to ignore
1281 /// side-effects.
1282 struct IgnoreSideEffectsRAII {
1283 EvalInfo &Info;
1284 EvalInfo::EvaluationMode OldMode;
1285 explicit IgnoreSideEffectsRAII(EvalInfo &Info)
1286 : Info(Info), OldMode(Info.EvalMode) {
1287 Info.EvalMode = EvalInfo::EM_IgnoreSideEffects;
1288 }
1289
1290 ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; }
1291 };
1292
1293 /// RAII object used to optionally suppress diagnostics and side-effects from
1294 /// a speculative evaluation.
1295 class SpeculativeEvaluationRAII {
1296 EvalInfo *Info = nullptr;
1297 Expr::EvalStatus OldStatus;
1298 unsigned OldSpeculativeEvaluationDepth;
1299
1300 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
1301 Info = Other.Info;
1302 OldStatus = Other.OldStatus;
1303 OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth;
1304 Other.Info = nullptr;
1305 }
1306
1307 void maybeRestoreState() {
1308 if (!Info)
1309 return;
1310
1311 Info->EvalStatus = OldStatus;
1312 Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth;
1313 }
1314
1315 public:
1316 SpeculativeEvaluationRAII() = default;
1317
1318 SpeculativeEvaluationRAII(
1319 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1320 : Info(&Info), OldStatus(Info.EvalStatus),
1321 OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) {
1322 Info.EvalStatus.Diag = NewDiag;
1323 Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1;
1324 }
1325
1326 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1327 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1328 moveFromAndCancel(std::move(Other));
1329 }
1330
1331 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1332 maybeRestoreState();
1333 moveFromAndCancel(std::move(Other));
1334 return *this;
1335 }
1336
1337 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1338 };
1339
1340 /// RAII object wrapping a full-expression or block scope, and handling
1341 /// the ending of the lifetime of temporaries created within it.
1342 template<ScopeKind Kind>
1343 class ScopeRAII {
1344 EvalInfo &Info;
1345 unsigned OldStackSize;
1346 public:
1347 ScopeRAII(EvalInfo &Info)
1348 : Info(Info), OldStackSize(Info.CleanupStack.size()) {
1349 // Push a new temporary version. This is needed to distinguish between
1350 // temporaries created in different iterations of a loop.
1351 Info.CurrentCall->pushTempVersion();
1352 }
1353 bool destroy(bool RunDestructors = true) {
1354 bool OK = cleanup(Info, RunDestructors, OldStackSize);
1355 OldStackSize = -1U;
1356 return OK;
1357 }
1358 ~ScopeRAII() {
1359 if (OldStackSize != -1U)
1360 destroy(false);
1361 // Body moved to a static method to encourage the compiler to inline away
1362 // instances of this class.
1363 Info.CurrentCall->popTempVersion();
1364 }
1365 private:
1366 static bool cleanup(EvalInfo &Info, bool RunDestructors,
1367 unsigned OldStackSize) {
1368 assert(OldStackSize <= Info.CleanupStack.size() &&((void)0)
1369 "running cleanups out of order?")((void)0);
1370
1371 // Run all cleanups for a block scope, and non-lifetime-extended cleanups
1372 // for a full-expression scope.
1373 bool Success = true;
1374 for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) {
1375 if (Info.CleanupStack[I - 1].isDestroyedAtEndOf(Kind)) {
1376 if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) {
1377 Success = false;
1378 break;
1379 }
1380 }
1381 }
1382
1383 // Compact any retained cleanups.
1384 auto NewEnd = Info.CleanupStack.begin() + OldStackSize;
1385 if (Kind != ScopeKind::Block)
1386 NewEnd =
1387 std::remove_if(NewEnd, Info.CleanupStack.end(), [](Cleanup &C) {
1388 return C.isDestroyedAtEndOf(Kind);
1389 });
1390 Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end());
1391 return Success;
1392 }
1393 };
1394 typedef ScopeRAII<ScopeKind::Block> BlockScopeRAII;
1395 typedef ScopeRAII<ScopeKind::FullExpression> FullExpressionRAII;
1396 typedef ScopeRAII<ScopeKind::Call> CallScopeRAII;
1397}
1398
1399bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1400 CheckSubobjectKind CSK) {
1401 if (Invalid)
1402 return false;
1403 if (isOnePastTheEnd()) {
1404 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1405 << CSK;
1406 setInvalid();
1407 return false;
1408 }
1409 // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there
1410 // must actually be at least one array element; even a VLA cannot have a
1411 // bound of zero. And if our index is nonzero, we already had a CCEDiag.
1412 return true;
1413}
1414
1415void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info,
1416 const Expr *E) {
1417 Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed);
1418 // Do not set the designator as invalid: we can represent this situation,
1419 // and correct handling of __builtin_object_size requires us to do so.
1420}
1421
1422void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1423 const Expr *E,
1424 const APSInt &N) {
1425 // If we're complaining, we must be able to statically determine the size of
1426 // the most derived array.
1427 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1428 Info.CCEDiag(E, diag::note_constexpr_array_index)
1429 << N << /*array*/ 0
1430 << static_cast<unsigned>(getMostDerivedArraySize());
1431 else
1432 Info.CCEDiag(E, diag::note_constexpr_array_index)
1433 << N << /*non-array*/ 1;
1434 setInvalid();
1435}
1436
1437CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1438 const FunctionDecl *Callee, const LValue *This,
1439 CallRef Call)
1440 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1441 Arguments(Call), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1442 Info.CurrentCall = this;
1443 ++Info.CallStackDepth;
1444}
1445
1446CallStackFrame::~CallStackFrame() {
1447 assert(Info.CurrentCall == this && "calls retired out of order")((void)0);
1448 --Info.CallStackDepth;
1449 Info.CurrentCall = Caller;
1450}
1451
1452static bool isRead(AccessKinds AK) {
1453 return AK == AK_Read || AK == AK_ReadObjectRepresentation;
1454}
1455
1456static bool isModification(AccessKinds AK) {
1457 switch (AK) {
1458 case AK_Read:
1459 case AK_ReadObjectRepresentation:
1460 case AK_MemberCall:
1461 case AK_DynamicCast:
1462 case AK_TypeId:
1463 return false;
1464 case AK_Assign:
1465 case AK_Increment:
1466 case AK_Decrement:
1467 case AK_Construct:
1468 case AK_Destroy:
1469 return true;
1470 }
1471 llvm_unreachable("unknown access kind")__builtin_unreachable();
1472}
1473
1474static bool isAnyAccess(AccessKinds AK) {
1475 return isRead(AK) || isModification(AK);
1476}
1477
1478/// Is this an access per the C++ definition?
1479static bool isFormalAccess(AccessKinds AK) {
1480 return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy;
1481}
1482
1483/// Is this kind of axcess valid on an indeterminate object value?
1484static bool isValidIndeterminateAccess(AccessKinds AK) {
1485 switch (AK) {
1486 case AK_Read:
1487 case AK_Increment:
1488 case AK_Decrement:
1489 // These need the object's value.
1490 return false;
1491
1492 case AK_ReadObjectRepresentation:
1493 case AK_Assign:
1494 case AK_Construct:
1495 case AK_Destroy:
1496 // Construction and destruction don't need the value.
1497 return true;
1498
1499 case AK_MemberCall:
1500 case AK_DynamicCast:
1501 case AK_TypeId:
1502 // These aren't really meaningful on scalars.
1503 return true;
1504 }
1505 llvm_unreachable("unknown access kind")__builtin_unreachable();
1506}
1507
1508namespace {
1509 struct ComplexValue {
1510 private:
1511 bool IsInt;
1512
1513 public:
1514 APSInt IntReal, IntImag;
1515 APFloat FloatReal, FloatImag;
1516
1517 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1518
1519 void makeComplexFloat() { IsInt = false; }
1520 bool isComplexFloat() const { return !IsInt; }
1521 APFloat &getComplexFloatReal() { return FloatReal; }
1522 APFloat &getComplexFloatImag() { return FloatImag; }
1523
1524 void makeComplexInt() { IsInt = true; }
1525 bool isComplexInt() const { return IsInt; }
1526 APSInt &getComplexIntReal() { return IntReal; }
1527 APSInt &getComplexIntImag() { return IntImag; }
1528
1529 void moveInto(APValue &v) const {
1530 if (isComplexFloat())
1531 v = APValue(FloatReal, FloatImag);
1532 else
1533 v = APValue(IntReal, IntImag);
1534 }
1535 void setFrom(const APValue &v) {
1536 assert(v.isComplexFloat() || v.isComplexInt())((void)0);
1537 if (v.isComplexFloat()) {
21
Taking false branch
1538 makeComplexFloat();
1539 FloatReal = v.getComplexFloatReal();
1540 FloatImag = v.getComplexFloatImag();
1541 } else {
1542 makeComplexInt();
1543 IntReal = v.getComplexIntReal();
22
Calling implicit copy assignment operator for 'APSInt'
1544 IntImag = v.getComplexIntImag();
1545 }
1546 }
1547 };
1548
1549 struct LValue {
1550 APValue::LValueBase Base;
1551 CharUnits Offset;
1552 SubobjectDesignator Designator;
1553 bool IsNullPtr : 1;
1554 bool InvalidBase : 1;
1555
1556 const APValue::LValueBase getLValueBase() const { return Base; }
1557 CharUnits &getLValueOffset() { return Offset; }
1558 const CharUnits &getLValueOffset() const { return Offset; }
1559 SubobjectDesignator &getLValueDesignator() { return Designator; }
1560 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1561 bool isNullPointer() const { return IsNullPtr;}
1562
1563 unsigned getLValueCallIndex() const { return Base.getCallIndex(); }
1564 unsigned getLValueVersion() const { return Base.getVersion(); }
1565
1566 void moveInto(APValue &V) const {
1567 if (Designator.Invalid)
1568 V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr);
1569 else {
1570 assert(!InvalidBase && "APValues can't handle invalid LValue bases")((void)0);
1571 V = APValue(Base, Offset, Designator.Entries,
1572 Designator.IsOnePastTheEnd, IsNullPtr);
1573 }
1574 }
1575 void setFrom(ASTContext &Ctx, const APValue &V) {
1576 assert(V.isLValue() && "Setting LValue from a non-LValue?")((void)0);
1577 Base = V.getLValueBase();
1578 Offset = V.getLValueOffset();
1579 InvalidBase = false;
1580 Designator = SubobjectDesignator(Ctx, V);
1581 IsNullPtr = V.isNullPointer();
1582 }
1583
1584 void set(APValue::LValueBase B, bool BInvalid = false) {
1585#ifndef NDEBUG1
1586 // We only allow a few types of invalid bases. Enforce that here.
1587 if (BInvalid) {
1588 const auto *E = B.get<const Expr *>();
1589 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&((void)0)
1590 "Unexpected type of invalid base")((void)0);
1591 }
1592#endif
1593
1594 Base = B;
1595 Offset = CharUnits::fromQuantity(0);
1596 InvalidBase = BInvalid;
1597 Designator = SubobjectDesignator(getType(B));
1598 IsNullPtr = false;
1599 }
1600
1601 void setNull(ASTContext &Ctx, QualType PointerTy) {
1602 Base = (const ValueDecl *)nullptr;
1603 Offset =
1604 CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy));
1605 InvalidBase = false;
1606 Designator = SubobjectDesignator(PointerTy->getPointeeType());
1607 IsNullPtr = true;
1608 }
1609
1610 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1611 set(B, true);
1612 }
1613
1614 std::string toString(ASTContext &Ctx, QualType T) const {
1615 APValue Printable;
1616 moveInto(Printable);
1617 return Printable.getAsString(Ctx, T);
1618 }
1619
1620 private:
1621 // Check that this LValue is not based on a null pointer. If it is, produce
1622 // a diagnostic and mark the designator as invalid.
1623 template <typename GenDiagType>
1624 bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) {
1625 if (Designator.Invalid)
1626 return false;
1627 if (IsNullPtr) {
1628 GenDiag();
1629 Designator.setInvalid();
1630 return false;
1631 }
1632 return true;
1633 }
1634
1635 public:
1636 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1637 CheckSubobjectKind CSK) {
1638 return checkNullPointerDiagnosingWith([&Info, E, CSK] {
1639 Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK;
1640 });
1641 }
1642
1643 bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E,
1644 AccessKinds AK) {
1645 return checkNullPointerDiagnosingWith([&Info, E, AK] {
1646 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
1647 });
1648 }
1649
1650 // Check this LValue refers to an object. If not, set the designator to be
1651 // invalid and emit a diagnostic.
1652 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1653 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1654 Designator.checkSubobject(Info, E, CSK);
1655 }
1656
1657 void addDecl(EvalInfo &Info, const Expr *E,
1658 const Decl *D, bool Virtual = false) {
1659 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1660 Designator.addDeclUnchecked(D, Virtual);
1661 }
1662 void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) {
1663 if (!Designator.Entries.empty()) {
1664 Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array);
1665 Designator.setInvalid();
1666 return;
1667 }
1668 if (checkSubobject(Info, E, CSK_ArrayToPointer)) {
1669 assert(getType(Base)->isPointerType() || getType(Base)->isArrayType())((void)0);
1670 Designator.FirstEntryIsAnUnsizedArray = true;
1671 Designator.addUnsizedArrayUnchecked(ElemTy);
1672 }
1673 }
1674 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1675 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1676 Designator.addArrayUnchecked(CAT);
1677 }
1678 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1679 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1680 Designator.addComplexUnchecked(EltTy, Imag);
1681 }
1682 void clearIsNullPointer() {
1683 IsNullPtr = false;
1684 }
1685 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1686 const APSInt &Index, CharUnits ElementSize) {
1687 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1688 // but we're not required to diagnose it and it's valid in C++.)
1689 if (!Index)
1690 return;
1691
1692 // Compute the new offset in the appropriate width, wrapping at 64 bits.
1693 // FIXME: When compiling for a 32-bit target, we should use 32-bit
1694 // offsets.
1695 uint64_t Offset64 = Offset.getQuantity();
1696 uint64_t ElemSize64 = ElementSize.getQuantity();
1697 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
1698 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64);
1699
1700 if (checkNullPointer(Info, E, CSK_ArrayIndex))
1701 Designator.adjustIndex(Info, E, Index);
1702 clearIsNullPointer();
1703 }
1704 void adjustOffset(CharUnits N) {
1705 Offset += N;
1706 if (N.getQuantity())
1707 clearIsNullPointer();
1708 }
1709 };
1710
1711 struct MemberPtr {
1712 MemberPtr() {}
1713 explicit MemberPtr(const ValueDecl *Decl) :
1714 DeclAndIsDerivedMember(Decl, false), Path() {}
1715
1716 /// The member or (direct or indirect) field referred to by this member
1717 /// pointer, or 0 if this is a null member pointer.
1718 const ValueDecl *getDecl() const {
1719 return DeclAndIsDerivedMember.getPointer();
1720 }
1721 /// Is this actually a member of some type derived from the relevant class?
1722 bool isDerivedMember() const {
1723 return DeclAndIsDerivedMember.getInt();
1724 }
1725 /// Get the class which the declaration actually lives in.
1726 const CXXRecordDecl *getContainingRecord() const {
1727 return cast<CXXRecordDecl>(
1728 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1729 }
1730
1731 void moveInto(APValue &V) const {
1732 V = APValue(getDecl(), isDerivedMember(), Path);
1733 }
1734 void setFrom(const APValue &V) {
1735 assert(V.isMemberPointer())((void)0);
1736 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1737 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1738 Path.clear();
1739 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1740 Path.insert(Path.end(), P.begin(), P.end());
1741 }
1742
1743 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1744 /// whether the member is a member of some class derived from the class type
1745 /// of the member pointer.
1746 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1747 /// Path - The path of base/derived classes from the member declaration's
1748 /// class (exclusive) to the class type of the member pointer (inclusive).
1749 SmallVector<const CXXRecordDecl*, 4> Path;
1750
1751 /// Perform a cast towards the class of the Decl (either up or down the
1752 /// hierarchy).
1753 bool castBack(const CXXRecordDecl *Class) {
1754 assert(!Path.empty())((void)0);
1755 const CXXRecordDecl *Expected;
1756 if (Path.size() >= 2)
1757 Expected = Path[Path.size() - 2];
1758 else
1759 Expected = getContainingRecord();
1760 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1761 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1762 // if B does not contain the original member and is not a base or
1763 // derived class of the class containing the original member, the result
1764 // of the cast is undefined.
1765 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1766 // (D::*). We consider that to be a language defect.
1767 return false;
1768 }
1769 Path.pop_back();
1770 return true;
1771 }
1772 /// Perform a base-to-derived member pointer cast.
1773 bool castToDerived(const CXXRecordDecl *Derived) {
1774 if (!getDecl())
1775 return true;
1776 if (!isDerivedMember()) {
1777 Path.push_back(Derived);
1778 return true;
1779 }
1780 if (!castBack(Derived))
1781 return false;
1782 if (Path.empty())
1783 DeclAndIsDerivedMember.setInt(false);
1784 return true;
1785 }
1786 /// Perform a derived-to-base member pointer cast.
1787 bool castToBase(const CXXRecordDecl *Base) {
1788 if (!getDecl())
1789 return true;
1790 if (Path.empty())
1791 DeclAndIsDerivedMember.setInt(true);
1792 if (isDerivedMember()) {
1793 Path.push_back(Base);
1794 return true;
1795 }
1796 return castBack(Base);
1797 }
1798 };
1799
1800 /// Compare two member pointers, which are assumed to be of the same type.
1801 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1802 if (!LHS.getDecl() || !RHS.getDecl())
1803 return !LHS.getDecl() && !RHS.getDecl();
1804 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1805 return false;
1806 return LHS.Path == RHS.Path;
1807 }
1808}
1809
1810static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1811static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1812 const LValue &This, const Expr *E,
1813 bool AllowNonLiteralTypes = false);
1814static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1815 bool InvalidBaseOK = false);
1816static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1817 bool InvalidBaseOK = false);
1818static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1819 EvalInfo &Info);
1820static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1821static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1822static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1823 EvalInfo &Info);
1824static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1825static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1826static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1827 EvalInfo &Info);
1828static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1829
1830/// Evaluate an integer or fixed point expression into an APResult.
1831static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
1832 EvalInfo &Info);
1833
1834/// Evaluate only a fixed point expression into an APResult.
1835static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
1836 EvalInfo &Info);
1837
1838//===----------------------------------------------------------------------===//
1839// Misc utilities
1840//===----------------------------------------------------------------------===//
1841
1842/// Negate an APSInt in place, converting it to a signed form if necessary, and
1843/// preserving its value (by extending by up to one bit as needed).
1844static void negateAsSigned(APSInt &Int) {
1845 if (Int.isUnsigned() || Int.isMinSignedValue()) {
1846 Int = Int.extend(Int.getBitWidth() + 1);
1847 Int.setIsSigned(true);
1848 }
1849 Int = -Int;
1850}
1851
1852template<typename KeyT>
1853APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
1854 ScopeKind Scope, LValue &LV) {
1855 unsigned Version = getTempVersion();
1856 APValue::LValueBase Base(Key, Index, Version);
1857 LV.set(Base);
1858 return createLocal(Base, Key, T, Scope);
1859}
1860
1861/// Allocate storage for a parameter of a function call made in this frame.
1862APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD,
1863 LValue &LV) {
1864 assert(Args.CallIndex == Index && "creating parameter in wrong frame")((void)0);
1865 APValue::LValueBase Base(PVD, Index, Args.Version);
1866 LV.set(Base);
1867 // We always destroy parameters at the end of the call, even if we'd allow
1868 // them to live to the end of the full-expression at runtime, in order to
1869 // give portable results and match other compilers.
1870 return createLocal(Base, PVD, PVD->getType(), ScopeKind::Call);
1871}
1872
1873APValue &CallStackFrame::createLocal(APValue::LValueBase Base, const void *Key,
1874 QualType T, ScopeKind Scope) {
1875 assert(Base.getCallIndex() == Index && "lvalue for wrong frame")((void)0);
1876 unsigned Version = Base.getVersion();
1877 APValue &Result = Temporaries[MapKeyTy(Key, Version)];
1878 assert(Result.isAbsent() && "local created multiple times")((void)0);
1879
1880 // If we're creating a local immediately in the operand of a speculative
1881 // evaluation, don't register a cleanup to be run outside the speculative
1882 // evaluation context, since we won't actually be able to initialize this
1883 // object.
1884 if (Index <= Info.SpeculativeEvaluationDepth) {
1885 if (T.isDestructedType())
1886 Info.noteSideEffect();
1887 } else {
1888 Info.CleanupStack.push_back(Cleanup(&Result, Base, T, Scope));
1889 }
1890 return Result;
1891}
1892
1893APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) {
1894 if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) {
1895 FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded);
1896 return nullptr;
1897 }
1898
1899 DynamicAllocLValue DA(NumHeapAllocs++);
1900 LV.set(APValue::LValueBase::getDynamicAlloc(DA, T));
1901 auto Result = HeapAllocs.emplace(std::piecewise_construct,
1902 std::forward_as_tuple(DA), std::tuple<>());
1903 assert(Result.second && "reused a heap alloc index?")((void)0);
1904 Result.first->second.AllocExpr = E;
1905 return &Result.first->second.Value;
1906}
1907
1908/// Produce a string describing the given constexpr call.
1909void CallStackFrame::describe(raw_ostream &Out) {
1910 unsigned ArgIndex = 0;
1911 bool IsMemberCall = isa<CXXMethodDecl>(Callee) &&
1912 !isa<CXXConstructorDecl>(Callee) &&
1913 cast<CXXMethodDecl>(Callee)->isInstance();
1914
1915 if (!IsMemberCall)
1916 Out << *Callee << '(';
1917
1918 if (This && IsMemberCall) {
1919 APValue Val;
1920 This->moveInto(Val);
1921 Val.printPretty(Out, Info.Ctx,
1922 This->Designator.MostDerivedType);
1923 // FIXME: Add parens around Val if needed.
1924 Out << "->" << *Callee << '(';
1925 IsMemberCall = false;
1926 }
1927
1928 for (FunctionDecl::param_const_iterator I = Callee->param_begin(),
1929 E = Callee->param_end(); I != E; ++I, ++ArgIndex) {
1930 if (ArgIndex > (unsigned)IsMemberCall)
1931 Out << ", ";
1932
1933 const ParmVarDecl *Param = *I;
1934 APValue *V = Info.getParamSlot(Arguments, Param);
1935 if (V)
1936 V->printPretty(Out, Info.Ctx, Param->getType());
1937 else
1938 Out << "<...>";
1939
1940 if (ArgIndex == 0 && IsMemberCall)
1941 Out << "->" << *Callee << '(';
1942 }
1943
1944 Out << ')';
1945}
1946
1947/// Evaluate an expression to see if it had side-effects, and discard its
1948/// result.
1949/// \return \c true if the caller should keep evaluating.
1950static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1951 assert(!E->isValueDependent())((void)0);
1952 APValue Scratch;
1953 if (!Evaluate(Scratch, Info, E))
1954 // We don't need the value, but we might have skipped a side effect here.
1955 return Info.noteSideEffect();
1956 return true;
1957}
1958
1959/// Should this call expression be treated as a string literal?
1960static bool IsStringLiteralCall(const CallExpr *E) {
1961 unsigned Builtin = E->getBuiltinCallee();
1962 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1963 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1964}
1965
1966static bool IsGlobalLValue(APValue::LValueBase B) {
1967 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1968 // constant expression of pointer type that evaluates to...
1969
1970 // ... a null pointer value, or a prvalue core constant expression of type
1971 // std::nullptr_t.
1972 if (!B) return true;
1973
1974 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1975 // ... the address of an object with static storage duration,
1976 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1977 return VD->hasGlobalStorage();
1978 if (isa<TemplateParamObjectDecl>(D))
1979 return true;
1980 // ... the address of a function,
1981 // ... the address of a GUID [MS extension],
1982 return isa<FunctionDecl>(D) || isa<MSGuidDecl>(D);
1983 }
1984
1985 if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>())
1986 return true;
1987
1988 const Expr *E = B.get<const Expr*>();
1989 switch (E->getStmtClass()) {
1990 default:
1991 return false;
1992 case Expr::CompoundLiteralExprClass: {
1993 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1994 return CLE->isFileScope() && CLE->isLValue();
1995 }
1996 case Expr::MaterializeTemporaryExprClass:
1997 // A materialized temporary might have been lifetime-extended to static
1998 // storage duration.
1999 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
2000 // A string literal has static storage duration.
2001 case Expr::StringLiteralClass:
2002 case Expr::PredefinedExprClass:
2003 case Expr::ObjCStringLiteralClass:
2004 case Expr::ObjCEncodeExprClass:
2005 return true;
2006 case Expr::ObjCBoxedExprClass:
2007 return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer();
2008 case Expr::CallExprClass:
2009 return IsStringLiteralCall(cast<CallExpr>(E));
2010 // For GCC compatibility, &&label has static storage duration.
2011 case Expr::AddrLabelExprClass:
2012 return true;
2013 // A Block literal expression may be used as the initialization value for
2014 // Block variables at global or local static scope.
2015 case Expr::BlockExprClass:
2016 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
2017 case Expr::ImplicitValueInitExprClass:
2018 // FIXME:
2019 // We can never form an lvalue with an implicit value initialization as its
2020 // base through expression evaluation, so these only appear in one case: the
2021 // implicit variable declaration we invent when checking whether a constexpr
2022 // constructor can produce a constant expression. We must assume that such
2023 // an expression might be a global lvalue.
2024 return true;
2025 }
2026}
2027
2028static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
2029 return LVal.Base.dyn_cast<const ValueDecl*>();
2030}
2031
2032static bool IsLiteralLValue(const LValue &Value) {
2033 if (Value.getLValueCallIndex())
2034 return false;
2035 const Expr *E = Value.Base.dyn_cast<const Expr*>();
2036 return E && !isa<MaterializeTemporaryExpr>(E);
2037}
2038
2039static bool IsWeakLValue(const LValue &Value) {
2040 const ValueDecl *Decl = GetLValueBaseDecl(Value);
2041 return Decl && Decl->isWeak();
2042}
2043
2044static bool isZeroSized(const LValue &Value) {
2045 const ValueDecl *Decl = GetLValueBaseDecl(Value);
2046 if (Decl && isa<VarDecl>(Decl)) {
2047 QualType Ty = Decl->getType();
2048 if (Ty->isArrayType())
2049 return Ty->isIncompleteType() ||
2050 Decl->getASTContext().getTypeSize(Ty) == 0;
2051 }
2052 return false;
2053}
2054
2055static bool HasSameBase(const LValue &A, const LValue &B) {
2056 if (!A.getLValueBase())
2057 return !B.getLValueBase();
2058 if (!B.getLValueBase())
2059 return false;
2060
2061 if (A.getLValueBase().getOpaqueValue() !=
2062 B.getLValueBase().getOpaqueValue())
2063 return false;
2064
2065 return A.getLValueCallIndex() == B.getLValueCallIndex() &&
2066 A.getLValueVersion() == B.getLValueVersion();
2067}
2068
2069static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
2070 assert(Base && "no location for a null lvalue")((void)0);
2071 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2072
2073 // For a parameter, find the corresponding call stack frame (if it still
2074 // exists), and point at the parameter of the function definition we actually
2075 // invoked.
2076 if (auto *PVD = dyn_cast_or_null<ParmVarDecl>(VD)) {
2077 unsigned Idx = PVD->getFunctionScopeIndex();
2078 for (CallStackFrame *F = Info.CurrentCall; F; F = F->Caller) {
2079 if (F->Arguments.CallIndex == Base.getCallIndex() &&
2080 F->Arguments.Version == Base.getVersion() && F->Callee &&
2081 Idx < F->Callee->getNumParams()) {
2082 VD = F->Callee->getParamDecl(Idx);
2083 break;
2084 }
2085 }
2086 }
2087
2088 if (VD)
2089 Info.Note(VD->getLocation(), diag::note_declared_at);
2090 else if (const Expr *E = Base.dyn_cast<const Expr*>())
2091 Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here);
2092 else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
2093 // FIXME: Produce a note for dangling pointers too.
2094 if (Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA))
2095 Info.Note((*Alloc)->AllocExpr->getExprLoc(),
2096 diag::note_constexpr_dynamic_alloc_here);
2097 }
2098 // We have no information to show for a typeid(T) object.
2099}
2100
2101enum class CheckEvaluationResultKind {
2102 ConstantExpression,
2103 FullyInitialized,
2104};
2105
2106/// Materialized temporaries that we've already checked to determine if they're
2107/// initializsed by a constant expression.
2108using CheckedTemporaries =
2109 llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>;
2110
2111static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2112 EvalInfo &Info, SourceLocation DiagLoc,
2113 QualType Type, const APValue &Value,
2114 ConstantExprKind Kind,
2115 SourceLocation SubobjectLoc,
2116 CheckedTemporaries &CheckedTemps);
2117
2118/// Check that this reference or pointer core constant expression is a valid
2119/// value for an address or reference constant expression. Return true if we
2120/// can fold this expression, whether or not it's a constant expression.
2121static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
2122 QualType Type, const LValue &LVal,
2123 ConstantExprKind Kind,
2124 CheckedTemporaries &CheckedTemps) {
2125 bool IsReferenceType = Type->isReferenceType();
2126
2127 APValue::LValueBase Base = LVal.getLValueBase();
2128 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
2129
2130 const Expr *BaseE = Base.dyn_cast<const Expr *>();
2131 const ValueDecl *BaseVD = Base.dyn_cast<const ValueDecl*>();
2132
2133 // Additional restrictions apply in a template argument. We only enforce the
2134 // C++20 restrictions here; additional syntactic and semantic restrictions
2135 // are applied elsewhere.
2136 if (isTemplateArgument(Kind)) {
2137 int InvalidBaseKind = -1;
2138 StringRef Ident;
2139 if (Base.is<TypeInfoLValue>())
2140 InvalidBaseKind = 0;
2141 else if (isa_and_nonnull<StringLiteral>(BaseE))
2142 InvalidBaseKind = 1;
2143 else if (isa_and_nonnull<MaterializeTemporaryExpr>(BaseE) ||
2144 isa_and_nonnull<LifetimeExtendedTemporaryDecl>(BaseVD))
2145 InvalidBaseKind = 2;
2146 else if (auto *PE = dyn_cast_or_null<PredefinedExpr>(BaseE)) {
2147 InvalidBaseKind = 3;
2148 Ident = PE->getIdentKindName();
2149 }
2150
2151 if (InvalidBaseKind != -1) {
2152 Info.FFDiag(Loc, diag::note_constexpr_invalid_template_arg)
2153 << IsReferenceType << !Designator.Entries.empty() << InvalidBaseKind
2154 << Ident;
2155 return false;
2156 }
2157 }
2158
2159 if (auto *FD = dyn_cast_or_null<FunctionDecl>(BaseVD)) {
2160 if (FD->isConsteval()) {
2161 Info.FFDiag(Loc, diag::note_consteval_address_accessible)
2162 << !Type->isAnyPointerType();
2163 Info.Note(FD->getLocation(), diag::note_declared_at);
2164 return false;
2165 }
2166 }
2167
2168 // Check that the object is a global. Note that the fake 'this' object we
2169 // manufacture when checking potential constant expressions is conservatively
2170 // assumed to be global here.
2171 if (!IsGlobalLValue(Base)) {
2172 if (Info.getLangOpts().CPlusPlus11) {
2173 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2174 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
2175 << IsReferenceType << !Designator.Entries.empty()
2176 << !!VD << VD;
2177
2178 auto *VarD = dyn_cast_or_null<VarDecl>(VD);
2179 if (VarD && VarD->isConstexpr()) {
2180 // Non-static local constexpr variables have unintuitive semantics:
2181 // constexpr int a = 1;
2182 // constexpr const int *p = &a;
2183 // ... is invalid because the address of 'a' is not constant. Suggest
2184 // adding a 'static' in this case.
2185 Info.Note(VarD->getLocation(), diag::note_constexpr_not_static)
2186 << VarD
2187 << FixItHint::CreateInsertion(VarD->getBeginLoc(), "static ");
2188 } else {
2189 NoteLValueLocation(Info, Base);
2190 }
2191 } else {
2192 Info.FFDiag(Loc);
2193 }
2194 // Don't allow references to temporaries to escape.
2195 return false;
2196 }
2197 assert((Info.checkingPotentialConstantExpression() ||((void)0)
2198 LVal.getLValueCallIndex() == 0) &&((void)0)
2199 "have call index for global lvalue")((void)0);
2200
2201 if (Base.is<DynamicAllocLValue>()) {
2202 Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc)
2203 << IsReferenceType << !Designator.Entries.empty();
2204 NoteLValueLocation(Info, Base);
2205 return false;
2206 }
2207
2208 if (BaseVD) {
2209 if (const VarDecl *Var = dyn_cast<const VarDecl>(BaseVD)) {
2210 // Check if this is a thread-local variable.
2211 if (Var->getTLSKind())
2212 // FIXME: Diagnostic!
2213 return false;
2214
2215 // A dllimport variable never acts like a constant, unless we're
2216 // evaluating a value for use only in name mangling.
2217 if (!isForManglingOnly(Kind) && Var->hasAttr<DLLImportAttr>())
2218 // FIXME: Diagnostic!
2219 return false;
2220 }
2221 if (const auto *FD = dyn_cast<const FunctionDecl>(BaseVD)) {
2222 // __declspec(dllimport) must be handled very carefully:
2223 // We must never initialize an expression with the thunk in C++.
2224 // Doing otherwise would allow the same id-expression to yield
2225 // different addresses for the same function in different translation
2226 // units. However, this means that we must dynamically initialize the
2227 // expression with the contents of the import address table at runtime.
2228 //
2229 // The C language has no notion of ODR; furthermore, it has no notion of
2230 // dynamic initialization. This means that we are permitted to
2231 // perform initialization with the address of the thunk.
2232 if (Info.getLangOpts().CPlusPlus && !isForManglingOnly(Kind) &&
2233 FD->hasAttr<DLLImportAttr>())
2234 // FIXME: Diagnostic!
2235 return false;
2236 }
2237 } else if (const auto *MTE =
2238 dyn_cast_or_null<MaterializeTemporaryExpr>(BaseE)) {
2239 if (CheckedTemps.insert(MTE).second) {
2240 QualType TempType = getType(Base);
2241 if (TempType.isDestructedType()) {
2242 Info.FFDiag(MTE->getExprLoc(),
2243 diag::note_constexpr_unsupported_temporary_nontrivial_dtor)
2244 << TempType;
2245 return false;
2246 }
2247
2248 APValue *V = MTE->getOrCreateValue(false);
2249 assert(V && "evasluation result refers to uninitialised temporary")((void)0);
2250 if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2251 Info, MTE->getExprLoc(), TempType, *V,
2252 Kind, SourceLocation(), CheckedTemps))
2253 return false;
2254 }
2255 }
2256
2257 // Allow address constant expressions to be past-the-end pointers. This is
2258 // an extension: the standard requires them to point to an object.
2259 if (!IsReferenceType)
2260 return true;
2261
2262 // A reference constant expression must refer to an object.
2263 if (!Base) {
2264 // FIXME: diagnostic
2265 Info.CCEDiag(Loc);
2266 return true;
2267 }
2268
2269 // Does this refer one past the end of some object?
2270 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
2271 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
2272 << !Designator.Entries.empty() << !!BaseVD << BaseVD;
2273 NoteLValueLocation(Info, Base);
2274 }
2275
2276 return true;
2277}
2278
2279/// Member pointers are constant expressions unless they point to a
2280/// non-virtual dllimport member function.
2281static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
2282 SourceLocation Loc,
2283 QualType Type,
2284 const APValue &Value,
2285 ConstantExprKind Kind) {
2286 const ValueDecl *Member = Value.getMemberPointerDecl();
2287 const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member);
2288 if (!FD)
2289 return true;
2290 if (FD->isConsteval()) {
2291 Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0;
2292 Info.Note(FD->getLocation(), diag::note_declared_at);
2293 return false;
2294 }
2295 return isForManglingOnly(Kind) || FD->isVirtual() ||
2296 !FD->hasAttr<DLLImportAttr>();
2297}
2298
2299/// Check that this core constant expression is of literal type, and if not,
2300/// produce an appropriate diagnostic.
2301static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
2302 const LValue *This = nullptr) {
2303 if (!E->isPRValue() || E->getType()->isLiteralType(Info.Ctx))
2304 return true;
2305
2306 // C++1y: A constant initializer for an object o [...] may also invoke
2307 // constexpr constructors for o and its subobjects even if those objects
2308 // are of non-literal class types.
2309 //
2310 // C++11 missed this detail for aggregates, so classes like this:
2311 // struct foo_t { union { int i; volatile int j; } u; };
2312 // are not (obviously) initializable like so:
2313 // __attribute__((__require_constant_initialization__))
2314 // static const foo_t x = {{0}};
2315 // because "i" is a subobject with non-literal initialization (due to the
2316 // volatile member of the union). See:
2317 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
2318 // Therefore, we use the C++1y behavior.
2319 if (This && Info.EvaluatingDecl == This->getLValueBase())
2320 return true;
2321
2322 // Prvalue constant expressions must be of literal types.
2323 if (Info.getLangOpts().CPlusPlus11)
2324 Info.FFDiag(E, diag::note_constexpr_nonliteral)
2325 << E->getType();
2326 else
2327 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2328 return false;
2329}
2330
2331static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2332 EvalInfo &Info, SourceLocation DiagLoc,
2333 QualType Type, const APValue &Value,
2334 ConstantExprKind Kind,
2335 SourceLocation SubobjectLoc,
2336 CheckedTemporaries &CheckedTemps) {
2337 if (!Value.hasValue()) {
2338 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
2339 << true << Type;
2340 if (SubobjectLoc.isValid())
2341 Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here);
2342 return false;
2343 }
2344
2345 // We allow _Atomic(T) to be initialized from anything that T can be
2346 // initialized from.
2347 if (const AtomicType *AT = Type->getAs<AtomicType>())
2348 Type = AT->getValueType();
2349
2350 // Core issue 1454: For a literal constant expression of array or class type,
2351 // each subobject of its value shall have been initialized by a constant
2352 // expression.
2353 if (Value.isArray()) {
2354 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
2355 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
2356 if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
2357 Value.getArrayInitializedElt(I), Kind,
2358 SubobjectLoc, CheckedTemps))
2359 return false;
2360 }
2361 if (!Value.hasArrayFiller())
2362 return true;
2363 return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
2364 Value.getArrayFiller(), Kind, SubobjectLoc,
2365 CheckedTemps);
2366 }
2367 if (Value.isUnion() && Value.getUnionField()) {
2368 return CheckEvaluationResult(
2369 CERK, Info, DiagLoc, Value.getUnionField()->getType(),
2370 Value.getUnionValue(), Kind, Value.getUnionField()->getLocation(),
2371 CheckedTemps);
2372 }
2373 if (Value.isStruct()) {
2374 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
2375 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
2376 unsigned BaseIndex = 0;
2377 for (const CXXBaseSpecifier &BS : CD->bases()) {
2378 if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
2379 Value.getStructBase(BaseIndex), Kind,
2380 BS.getBeginLoc(), CheckedTemps))
2381 return false;
2382 ++BaseIndex;
2383 }
2384 }
2385 for (const auto *I : RD->fields()) {
2386 if (I->isUnnamedBitfield())
2387 continue;
2388
2389 if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(),
2390 Value.getStructField(I->getFieldIndex()),
2391 Kind, I->getLocation(), CheckedTemps))
2392 return false;
2393 }
2394 }
2395
2396 if (Value.isLValue() &&
2397 CERK == CheckEvaluationResultKind::ConstantExpression) {
2398 LValue LVal;
2399 LVal.setFrom(Info.Ctx, Value);
2400 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Kind,
2401 CheckedTemps);
2402 }
2403
2404 if (Value.isMemberPointer() &&
2405 CERK == CheckEvaluationResultKind::ConstantExpression)
2406 return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Kind);
2407
2408 // Everything else is fine.
2409 return true;
2410}
2411
2412/// Check that this core constant expression value is a valid value for a
2413/// constant expression. If not, report an appropriate diagnostic. Does not
2414/// check that the expression is of literal type.
2415static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
2416 QualType Type, const APValue &Value,
2417 ConstantExprKind Kind) {
2418 // Nothing to check for a constant expression of type 'cv void'.
2419 if (Type->isVoidType())
2420 return true;
2421
2422 CheckedTemporaries CheckedTemps;
2423 return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2424 Info, DiagLoc, Type, Value, Kind,
2425 SourceLocation(), CheckedTemps);
2426}
2427
2428/// Check that this evaluated value is fully-initialized and can be loaded by
2429/// an lvalue-to-rvalue conversion.
2430static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc,
2431 QualType Type, const APValue &Value) {
2432 CheckedTemporaries CheckedTemps;
2433 return CheckEvaluationResult(
2434 CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
2435 ConstantExprKind::Normal, SourceLocation(), CheckedTemps);
2436}
2437
2438/// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
2439/// "the allocated storage is deallocated within the evaluation".
2440static bool CheckMemoryLeaks(EvalInfo &Info) {
2441 if (!Info.HeapAllocs.empty()) {
2442 // We can still fold to a constant despite a compile-time memory leak,
2443 // so long as the heap allocation isn't referenced in the result (we check
2444 // that in CheckConstantExpression).
2445 Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr,
2446 diag::note_constexpr_memory_leak)
2447 << unsigned(Info.HeapAllocs.size() - 1);
2448 }
2449 return true;
2450}
2451
2452static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
2453 // A null base expression indicates a null pointer. These are always
2454 // evaluatable, and they are false unless the offset is zero.
2455 if (!Value.getLValueBase()) {
2456 Result = !Value.getLValueOffset().isZero();
2457 return true;
2458 }
2459
2460 // We have a non-null base. These are generally known to be true, but if it's
2461 // a weak declaration it can be null at runtime.
2462 Result = true;
2463 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
2464 return !Decl || !Decl->isWeak();
2465}
2466
2467static bool HandleConversionToBool(const APValue &Val, bool &Result) {
2468 switch (Val.getKind()) {
2469 case APValue::None:
2470 case APValue::Indeterminate:
2471 return false;
2472 case APValue::Int:
2473 Result = Val.getInt().getBoolValue();
2474 return true;
2475 case APValue::FixedPoint:
2476 Result = Val.getFixedPoint().getBoolValue();
2477 return true;
2478 case APValue::Float:
2479 Result = !Val.getFloat().isZero();
2480 return true;
2481 case APValue::ComplexInt:
2482 Result = Val.getComplexIntReal().getBoolValue() ||
2483 Val.getComplexIntImag().getBoolValue();
2484 return true;
2485 case APValue::ComplexFloat:
2486 Result = !Val.getComplexFloatReal().isZero() ||
2487 !Val.getComplexFloatImag().isZero();
2488 return true;
2489 case APValue::LValue:
2490 return EvalPointerValueAsBool(Val, Result);
2491 case APValue::MemberPointer:
2492 Result = Val.getMemberPointerDecl();
2493 return true;
2494 case APValue::Vector:
2495 case APValue::Array:
2496 case APValue::Struct:
2497 case APValue::Union:
2498 case APValue::AddrLabelDiff:
2499 return false;
2500 }
2501
2502 llvm_unreachable("unknown APValue kind")__builtin_unreachable();
2503}
2504
2505static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
2506 EvalInfo &Info) {
2507 assert(!E->isValueDependent())((void)0);
2508 assert(E->isPRValue() && "missing lvalue-to-rvalue conv in bool condition")((void)0);
2509 APValue Val;
2510 if (!Evaluate(Val, Info, E))
2511 return false;
2512 return HandleConversionToBool(Val, Result);
2513}
2514
2515template<typename T>
2516static bool HandleOverflow(EvalInfo &Info, const Expr *E,
2517 const T &SrcValue, QualType DestType) {
2518 Info.CCEDiag(E, diag::note_constexpr_overflow)
2519 << SrcValue << DestType;
2520 return Info.noteUndefinedBehavior();
2521}
2522
2523static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
2524 QualType SrcType, const APFloat &Value,
2525 QualType DestType, APSInt &Result) {
2526 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
2527 // Determine whether we are converting to unsigned or signed.
2528 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
2529
2530 Result = APSInt(DestWidth, !DestSigned);
2531 bool ignored;
2532 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
2533 & APFloat::opInvalidOp)
2534 return HandleOverflow(Info, E, Value, DestType);
2535 return true;
2536}
2537
2538/// Get rounding mode used for evaluation of the specified expression.
2539/// \param[out] DynamicRM Is set to true is the requested rounding mode is
2540/// dynamic.
2541/// If rounding mode is unknown at compile time, still try to evaluate the
2542/// expression. If the result is exact, it does not depend on rounding mode.
2543/// So return "tonearest" mode instead of "dynamic".
2544static llvm::RoundingMode getActiveRoundingMode(EvalInfo &Info, const Expr *E,
2545 bool &DynamicRM) {
2546 llvm::RoundingMode RM =
2547 E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).getRoundingMode();
2548 DynamicRM = (RM == llvm::RoundingMode::Dynamic);
2549 if (DynamicRM)
2550 RM = llvm::RoundingMode::NearestTiesToEven;
2551 return RM;
2552}
2553
2554/// Check if the given evaluation result is allowed for constant evaluation.
2555static bool checkFloatingPointResult(EvalInfo &Info, const Expr *E,
2556 APFloat::opStatus St) {
2557 // In a constant context, assume that any dynamic rounding mode or FP
2558 // exception state matches the default floating-point environment.
2559 if (Info.InConstantContext)
2560 return true;
2561
2562 FPOptions FPO = E->getFPFeaturesInEffect(Info.Ctx.getLangOpts());
2563 if ((St & APFloat::opInexact) &&
2564 FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) {
2565 // Inexact result means that it depends on rounding mode. If the requested
2566 // mode is dynamic, the evaluation cannot be made in compile time.
2567 Info.FFDiag(E, diag::note_constexpr_dynamic_rounding);
2568 return false;
2569 }
2570
2571 if ((St != APFloat::opOK) &&
2572 (FPO.getRoundingMode() == llvm::RoundingMode::Dynamic ||
2573 FPO.getFPExceptionMode() != LangOptions::FPE_Ignore ||
2574 FPO.getAllowFEnvAccess())) {
2575 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
2576 return false;
2577 }
2578
2579 if ((St & APFloat::opStatus::opInvalidOp) &&
2580 FPO.getFPExceptionMode() != LangOptions::FPE_Ignore) {
2581 // There is no usefully definable result.
2582 Info.FFDiag(E);
2583 return false;
2584 }
2585
2586 // FIXME: if:
2587 // - evaluation triggered other FP exception, and
2588 // - exception mode is not "ignore", and
2589 // - the expression being evaluated is not a part of global variable
2590 // initializer,
2591 // the evaluation probably need to be rejected.
2592 return true;
2593}
2594
2595static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
2596 QualType SrcType, QualType DestType,
2597 APFloat &Result) {
2598 assert(isa<CastExpr>(E) || isa<CompoundAssignOperator>(E))((void)0);
2599 bool DynamicRM;
2600 llvm::RoundingMode RM = getActiveRoundingMode(Info, E, DynamicRM);
2601 APFloat::opStatus St;
2602 APFloat Value = Result;
2603 bool ignored;
2604 St = Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), RM, &ignored);
2605 return checkFloatingPointResult(Info, E, St);
2606}
2607
2608static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
2609 QualType DestType, QualType SrcType,
2610 const APSInt &Value) {
2611 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
2612 // Figure out if this is a truncate, extend or noop cast.
2613 // If the input is signed, do a sign extend, noop, or truncate.
2614 APSInt Result = Value.extOrTrunc(DestWidth);
2615 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
2616 if (DestType->isBooleanType())
2617 Result = Value.getBoolValue();
2618 return Result;
2619}
2620
2621static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
2622 const FPOptions FPO,
2623 QualType SrcType, const APSInt &Value,
2624 QualType DestType, APFloat &Result) {
2625 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
2626 APFloat::opStatus St = Result.convertFromAPInt(Value, Value.isSigned(),
2627 APFloat::rmNearestTiesToEven);
2628 if (!Info.InConstantContext && St != llvm::APFloatBase::opOK &&
2629 FPO.isFPConstrained()) {
2630 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
2631 return false;
2632 }
2633 return true;
2634}
2635
2636static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
2637 APValue &Value, const FieldDecl *FD) {
2638 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield")((void)0);
2639
2640 if (!Value.isInt()) {
2641 // Trying to store a pointer-cast-to-integer into a bitfield.
2642 // FIXME: In this case, we should provide the diagnostic for casting
2643 // a pointer to an integer.
2644 assert(Value.isLValue() && "integral value neither int nor lvalue?")((void)0);
2645 Info.FFDiag(E);
2646 return false;
2647 }
2648
2649 APSInt &Int = Value.getInt();
2650 unsigned OldBitWidth = Int.getBitWidth();
2651 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
2652 if (NewBitWidth < OldBitWidth)
2653 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
2654 return true;
2655}
2656
2657static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
2658 llvm::APInt &Res) {
2659 APValue SVal;
2660 if (!Evaluate(SVal, Info, E))
2661 return false;
2662 if (SVal.isInt()) {
2663 Res = SVal.getInt();
2664 return true;
2665 }
2666 if (SVal.isFloat()) {
2667 Res = SVal.getFloat().bitcastToAPInt();
2668 return true;
2669 }
2670 if (SVal.isVector()) {
2671 QualType VecTy = E->getType();
2672 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
2673 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
2674 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
2675 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
2676 Res = llvm::APInt::getNullValue(VecSize);
2677 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
2678 APValue &Elt = SVal.getVectorElt(i);
2679 llvm::APInt EltAsInt;
2680 if (Elt.isInt()) {
2681 EltAsInt = Elt.getInt();
2682 } else if (Elt.isFloat()) {
2683 EltAsInt = Elt.getFloat().bitcastToAPInt();
2684 } else {
2685 // Don't try to handle vectors of anything other than int or float
2686 // (not sure if it's possible to hit this case).
2687 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2688 return false;
2689 }
2690 unsigned BaseEltSize = EltAsInt.getBitWidth();
2691 if (BigEndian)
2692 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
2693 else
2694 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
2695 }
2696 return true;
2697 }
2698 // Give up if the input isn't an int, float, or vector. For example, we
2699 // reject "(v4i16)(intptr_t)&a".
2700 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2701 return false;
2702}
2703
2704/// Perform the given integer operation, which is known to need at most BitWidth
2705/// bits, and check for overflow in the original type (if that type was not an
2706/// unsigned type).
2707template<typename Operation>
2708static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
2709 const APSInt &LHS, const APSInt &RHS,
2710 unsigned BitWidth, Operation Op,
2711 APSInt &Result) {
2712 if (LHS.isUnsigned()) {
2713 Result = Op(LHS, RHS);
2714 return true;
2715 }
2716
2717 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
2718 Result = Value.trunc(LHS.getBitWidth());
2719 if (Result.extend(BitWidth) != Value) {
2720 if (Info.checkingForUndefinedBehavior())
2721 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
2722 diag::warn_integer_constant_overflow)
2723 << toString(Result, 10) << E->getType();
2724 return HandleOverflow(Info, E, Value, E->getType());
2725 }
2726 return true;
2727}
2728
2729/// Perform the given binary integer operation.
2730static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
2731 BinaryOperatorKind Opcode, APSInt RHS,
2732 APSInt &Result) {
2733 switch (Opcode) {
2734 default:
2735 Info.FFDiag(E);
2736 return false;
2737 case BO_Mul:
2738 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
2739 std::multiplies<APSInt>(), Result);
2740 case BO_Add:
2741 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2742 std::plus<APSInt>(), Result);
2743 case BO_Sub:
2744 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2745 std::minus<APSInt>(), Result);
2746 case BO_And: Result = LHS & RHS; return true;
2747 case BO_Xor: Result = LHS ^ RHS; return true;
2748 case BO_Or: Result = LHS | RHS; return true;
2749 case BO_Div:
2750 case BO_Rem:
2751 if (RHS == 0) {
2752 Info.FFDiag(E, diag::note_expr_divide_by_zero);
2753 return false;
2754 }
2755 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2756 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2757 // this operation and gives the two's complement result.
2758 if (RHS.isNegative() && RHS.isAllOnesValue() &&
2759 LHS.isSigned() && LHS.isMinSignedValue())
2760 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
2761 E->getType());
2762 return true;
2763 case BO_Shl: {
2764 if (Info.getLangOpts().OpenCL)
2765 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2766 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2767 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2768 RHS.isUnsigned());
2769 else if (RHS.isSigned() && RHS.isNegative()) {
2770 // During constant-folding, a negative shift is an opposite shift. Such
2771 // a shift is not a constant expression.
2772 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2773 RHS = -RHS;
2774 goto shift_right;
2775 }
2776 shift_left:
2777 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2778 // the shifted type.
2779 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2780 if (SA != RHS) {
2781 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2782 << RHS << E->getType() << LHS.getBitWidth();
2783 } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) {
2784 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2785 // operand, and must not overflow the corresponding unsigned type.
2786 // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to
2787 // E1 x 2^E2 module 2^N.
2788 if (LHS.isNegative())
2789 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2790 else if (LHS.countLeadingZeros() < SA)
2791 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2792 }
2793 Result = LHS << SA;
2794 return true;
2795 }
2796 case BO_Shr: {
2797 if (Info.getLangOpts().OpenCL)
2798 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2799 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2800 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2801 RHS.isUnsigned());
2802 else if (RHS.isSigned() && RHS.isNegative()) {
2803 // During constant-folding, a negative shift is an opposite shift. Such a
2804 // shift is not a constant expression.
2805 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2806 RHS = -RHS;
2807 goto shift_left;
2808 }
2809 shift_right:
2810 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2811 // shifted type.
2812 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2813 if (SA != RHS)
2814 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2815 << RHS << E->getType() << LHS.getBitWidth();
2816 Result = LHS >> SA;
2817 return true;
2818 }
2819
2820 case BO_LT: Result = LHS < RHS; return true;
2821 case BO_GT: Result = LHS > RHS; return true;
2822 case BO_LE: Result = LHS <= RHS; return true;
2823 case BO_GE: Result = LHS >= RHS; return true;
2824 case BO_EQ: Result = LHS == RHS; return true;
2825 case BO_NE: Result = LHS != RHS; return true;
2826 case BO_Cmp:
2827 llvm_unreachable("BO_Cmp should be handled elsewhere")__builtin_unreachable();
2828 }
2829}
2830
2831/// Perform the given binary floating-point operation, in-place, on LHS.
2832static bool handleFloatFloatBinOp(EvalInfo &Info, const BinaryOperator *E,
2833 APFloat &LHS, BinaryOperatorKind Opcode,
2834 const APFloat &RHS) {
2835 bool DynamicRM;
2836 llvm::RoundingMode RM = getActiveRoundingMode(Info, E, DynamicRM);
2837 APFloat::opStatus St;
2838 switch (Opcode) {
2839 default:
2840 Info.FFDiag(E);
2841 return false;
2842 case BO_Mul:
2843 St = LHS.multiply(RHS, RM);
2844 break;
2845 case BO_Add:
2846 St = LHS.add(RHS, RM);
2847 break;
2848 case BO_Sub:
2849 St = LHS.subtract(RHS, RM);
2850 break;
2851 case BO_Div:
2852 // [expr.mul]p4:
2853 // If the second operand of / or % is zero the behavior is undefined.
2854 if (RHS.isZero())
2855 Info.CCEDiag(E, diag::note_expr_divide_by_zero);
2856 St = LHS.divide(RHS, RM);
2857 break;
2858 }
2859
2860 // [expr.pre]p4:
2861 // If during the evaluation of an expression, the result is not
2862 // mathematically defined [...], the behavior is undefined.
2863 // FIXME: C++ rules require us to not conform to IEEE 754 here.
2864 if (LHS.isNaN()) {
2865 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2866 return Info.noteUndefinedBehavior();
2867 }
2868
2869 return checkFloatingPointResult(Info, E, St);
2870}
2871
2872static bool handleLogicalOpForVector(const APInt &LHSValue,
2873 BinaryOperatorKind Opcode,
2874 const APInt &RHSValue, APInt &Result) {
2875 bool LHS = (LHSValue != 0);
2876 bool RHS = (RHSValue != 0);
2877
2878 if (Opcode == BO_LAnd)
2879 Result = LHS && RHS;
2880 else
2881 Result = LHS || RHS;
2882 return true;
2883}
2884static bool handleLogicalOpForVector(const APFloat &LHSValue,
2885 BinaryOperatorKind Opcode,
2886 const APFloat &RHSValue, APInt &Result) {
2887 bool LHS = !LHSValue.isZero();
2888 bool RHS = !RHSValue.isZero();
2889
2890 if (Opcode == BO_LAnd)
2891 Result = LHS && RHS;
2892 else
2893 Result = LHS || RHS;
2894 return true;
2895}
2896
2897static bool handleLogicalOpForVector(const APValue &LHSValue,
2898 BinaryOperatorKind Opcode,
2899 const APValue &RHSValue, APInt &Result) {
2900 // The result is always an int type, however operands match the first.
2901 if (LHSValue.getKind() == APValue::Int)
2902 return handleLogicalOpForVector(LHSValue.getInt(), Opcode,
2903 RHSValue.getInt(), Result);
2904 assert(LHSValue.getKind() == APValue::Float && "Should be no other options")((void)0);
2905 return handleLogicalOpForVector(LHSValue.getFloat(), Opcode,
2906 RHSValue.getFloat(), Result);
2907}
2908
2909template <typename APTy>
2910static bool
2911handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode,
2912 const APTy &RHSValue, APInt &Result) {
2913 switch (Opcode) {
2914 default:
2915 llvm_unreachable("unsupported binary operator")__builtin_unreachable();
2916 case BO_EQ:
2917 Result = (LHSValue == RHSValue);
2918 break;
2919 case BO_NE:
2920 Result = (LHSValue != RHSValue);
2921 break;
2922 case BO_LT:
2923 Result = (LHSValue < RHSValue);
2924 break;
2925 case BO_GT:
2926 Result = (LHSValue > RHSValue);
2927 break;
2928 case BO_LE:
2929 Result = (LHSValue <= RHSValue);
2930 break;
2931 case BO_GE:
2932 Result = (LHSValue >= RHSValue);
2933 break;
2934 }
2935
2936 return true;
2937}
2938
2939static bool handleCompareOpForVector(const APValue &LHSValue,
2940 BinaryOperatorKind Opcode,
2941 const APValue &RHSValue, APInt &Result) {
2942 // The result is always an int type, however operands match the first.
2943 if (LHSValue.getKind() == APValue::Int)
2944 return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode,
2945 RHSValue.getInt(), Result);
2946 assert(LHSValue.getKind() == APValue::Float && "Should be no other options")((void)0);
2947 return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode,
2948 RHSValue.getFloat(), Result);
2949}
2950
2951// Perform binary operations for vector types, in place on the LHS.
2952static bool handleVectorVectorBinOp(EvalInfo &Info, const BinaryOperator *E,
2953 BinaryOperatorKind Opcode,
2954 APValue &LHSValue,
2955 const APValue &RHSValue) {
2956 assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&((void)0)
2957 "Operation not supported on vector types")((void)0);
2958
2959 const auto *VT = E->getType()->castAs<VectorType>();
2960 unsigned NumElements = VT->getNumElements();
2961 QualType EltTy = VT->getElementType();
2962
2963 // In the cases (typically C as I've observed) where we aren't evaluating
2964 // constexpr but are checking for cases where the LHS isn't yet evaluatable,
2965 // just give up.
2966 if (!LHSValue.isVector()) {
2967 assert(LHSValue.isLValue() &&((void)0)
2968 "A vector result that isn't a vector OR uncalculated LValue")((void)0);
2969 Info.FFDiag(E);
2970 return false;
2971 }
2972
2973 assert(LHSValue.getVectorLength() == NumElements &&((void)0)
2974 RHSValue.getVectorLength() == NumElements && "Different vector sizes")((void)0);
2975
2976 SmallVector<APValue, 4> ResultElements;
2977
2978 for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) {
2979 APValue LHSElt = LHSValue.getVectorElt(EltNum);
2980 APValue RHSElt = RHSValue.getVectorElt(EltNum);
2981
2982 if (EltTy->isIntegerType()) {
2983 APSInt EltResult{Info.Ctx.getIntWidth(EltTy),
2984 EltTy->isUnsignedIntegerType()};
2985 bool Success = true;
2986
2987 if (BinaryOperator::isLogicalOp(Opcode))
2988 Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult);
2989 else if (BinaryOperator::isComparisonOp(Opcode))
2990 Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult);
2991 else
2992 Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode,
2993 RHSElt.getInt(), EltResult);
2994
2995 if (!Success) {
2996 Info.FFDiag(E);
2997 return false;
2998 }
2999 ResultElements.emplace_back(EltResult);
3000
3001 } else if (EltTy->isFloatingType()) {
3002 assert(LHSElt.getKind() == APValue::Float &&((void)0)
3003 RHSElt.getKind() == APValue::Float &&((void)0)
3004 "Mismatched LHS/RHS/Result Type")((void)0);
3005 APFloat LHSFloat = LHSElt.getFloat();
3006
3007 if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode,
3008 RHSElt.getFloat())) {
3009 Info.FFDiag(E);
3010 return false;
3011 }
3012
3013 ResultElements.emplace_back(LHSFloat);
3014 }
3015 }
3016
3017 LHSValue = APValue(ResultElements.data(), ResultElements.size());
3018 return true;
3019}
3020
3021/// Cast an lvalue referring to a base subobject to a derived class, by
3022/// truncating the lvalue's path to the given length.
3023static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
3024 const RecordDecl *TruncatedType,
3025 unsigned TruncatedElements) {
3026 SubobjectDesignator &D = Result.Designator;
3027
3028 // Check we actually point to a derived class object.
3029 if (TruncatedElements == D.Entries.size())
3030 return true;
3031 assert(TruncatedElements >= D.MostDerivedPathLength &&((void)0)
3032 "not casting to a derived class")((void)0);
3033 if (!Result.checkSubobject(Info, E, CSK_Derived))
3034 return false;
3035
3036 // Truncate the path to the subobject, and remove any derived-to-base offsets.
3037 const RecordDecl *RD = TruncatedType;
3038 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
3039 if (RD->isInvalidDecl()) return false;
3040 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
3041 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
3042 if (isVirtualBaseClass(D.Entries[I]))
3043 Result.Offset -= Layout.getVBaseClassOffset(Base);
3044 else
3045 Result.Offset -= Layout.getBaseClassOffset(Base);
3046 RD = Base;
3047 }
3048 D.Entries.resize(TruncatedElements);
3049 return true;
3050}
3051
3052static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3053 const CXXRecordDecl *Derived,
3054 const CXXRecordDecl *Base,
3055 const ASTRecordLayout *RL = nullptr) {
3056 if (!RL) {
3057 if (Derived->isInvalidDecl()) return false;
3058 RL = &Info.Ctx.getASTRecordLayout(Derived);
3059 }
3060
3061 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
3062 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
3063 return true;
3064}
3065
3066static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3067 const CXXRecordDecl *DerivedDecl,
3068 const CXXBaseSpecifier *Base) {
3069 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
3070
3071 if (!Base->isVirtual())
3072 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
3073
3074 SubobjectDesignator &D = Obj.Designator;
3075 if (D.Invalid)
3076 return false;
3077
3078 // Extract most-derived object and corresponding type.
3079 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
3080 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
3081 return false;
3082
3083 // Find the virtual base class.
3084 if (DerivedDecl->isInvalidDecl()) return false;
3085 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
3086 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
3087 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
3088 return true;
3089}
3090
3091static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
3092 QualType Type, LValue &Result) {
3093 for (CastExpr::path_const_iterator PathI = E->path_begin(),
3094 PathE = E->path_end();
3095 PathI != PathE; ++PathI) {
3096 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
3097 *PathI))
3098 return false;
3099 Type = (*PathI)->getType();
3100 }
3101 return true;
3102}
3103
3104/// Cast an lvalue referring to a derived class to a known base subobject.
3105static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result,
3106 const CXXRecordDecl *DerivedRD,
3107 const CXXRecordDecl *BaseRD) {
3108 CXXBasePaths Paths(/*FindAmbiguities=*/false,
3109 /*RecordPaths=*/true, /*DetectVirtual=*/false);
3110 if (!DerivedRD->isDerivedFrom(BaseRD, Paths))
3111 llvm_unreachable("Class must be derived from the passed in base class!")__builtin_unreachable();
3112
3113 for (CXXBasePathElement &Elem : Paths.front())
3114 if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base))
3115 return false;
3116 return true;
3117}
3118
3119/// Update LVal to refer to the given field, which must be a member of the type
3120/// currently described by LVal.
3121static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
3122 const FieldDecl *FD,
3123 const ASTRecordLayout *RL = nullptr) {
3124 if (!RL) {
3125 if (FD->getParent()->isInvalidDecl()) return false;
3126 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
3127 }
3128
3129 unsigned I = FD->getFieldIndex();
3130 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
3131 LVal.addDecl(Info, E, FD);
3132 return true;
3133}
3134
3135/// Update LVal to refer to the given indirect field.
3136static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
3137 LValue &LVal,
3138 const IndirectFieldDecl *IFD) {
3139 for (const auto *C : IFD->chain())
3140 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
3141 return false;
3142 return true;
3143}
3144
3145/// Get the size of the given type in char units.
3146static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
3147 QualType Type, CharUnits &Size) {
3148 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
3149 // extension.
3150 if (Type->isVoidType() || Type->isFunctionType()) {
3151 Size = CharUnits::One();
3152 return true;
3153 }
3154
3155 if (Type->isDependentType()) {
3156 Info.FFDiag(Loc);
3157 return false;
3158 }
3159
3160 if (!Type->isConstantSizeType()) {
3161 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
3162 // FIXME: Better diagnostic.
3163 Info.FFDiag(Loc);
3164 return false;
3165 }
3166
3167 Size = Info.Ctx.getTypeSizeInChars(Type);
3168 return true;
3169}
3170
3171/// Update a pointer value to model pointer arithmetic.
3172/// \param Info - Information about the ongoing evaluation.
3173/// \param E - The expression being evaluated, for diagnostic purposes.
3174/// \param LVal - The pointer value to be updated.
3175/// \param EltTy - The pointee type represented by LVal.
3176/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
3177static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3178 LValue &LVal, QualType EltTy,
3179 APSInt Adjustment) {
3180 CharUnits SizeOfPointee;
3181 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
3182 return false;
3183
3184 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
3185 return true;
3186}
3187
3188static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3189 LValue &LVal, QualType EltTy,
3190 int64_t Adjustment) {
3191 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
3192 APSInt::get(Adjustment));
3193}
3194
3195/// Update an lvalue to refer to a component of a complex number.
3196/// \param Info - Information about the ongoing evaluation.
3197/// \param LVal - The lvalue to be updated.
3198/// \param EltTy - The complex number's component type.
3199/// \param Imag - False for the real component, true for the imaginary.
3200static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
3201 LValue &LVal, QualType EltTy,
3202 bool Imag) {
3203 if (Imag) {
3204 CharUnits SizeOfComponent;
3205 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
3206 return false;
3207 LVal.Offset += SizeOfComponent;
3208 }
3209 LVal.addComplex(Info, E, EltTy, Imag);
3210 return true;
3211}
3212
3213/// Try to evaluate the initializer for a variable declaration.
3214///
3215/// \param Info Information about the ongoing evaluation.
3216/// \param E An expression to be used when printing diagnostics.
3217/// \param VD The variable whose initializer should be obtained.
3218/// \param Version The version of the variable within the frame.
3219/// \param Frame The frame in which the variable was created. Must be null
3220/// if this variable is not local to the evaluation.
3221/// \param Result Filled in with a pointer to the value of the variable.
3222static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
3223 const VarDecl *VD, CallStackFrame *Frame,
3224 unsigned Version, APValue *&Result) {
3225 APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);
3226
3227 // If this is a local variable, dig out its value.
3228 if (Frame) {
3229 Result = Frame->getTemporary(VD, Version);
3230 if (Result)
3231 return true;
3232
3233 if (!isa<ParmVarDecl>(VD)) {
3234 // Assume variables referenced within a lambda's call operator that were
3235 // not declared within the call operator are captures and during checking
3236 // of a potential constant expression, assume they are unknown constant
3237 // expressions.
3238 assert(isLambdaCallOperator(Frame->Callee) &&((void)0)
3239 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&((void)0)
3240 "missing value for local variable")((void)0);
3241 if (Info.checkingPotentialConstantExpression())
3242 return false;
3243 // FIXME: This diagnostic is bogus; we do support captures. Is this code
3244 // still reachable at all?
3245 Info.FFDiag(E->getBeginLoc(),
3246 diag::note_unimplemented_constexpr_lambda_feature_ast)
3247 << "captures not currently allowed";
3248 return false;
3249 }
3250 }
3251
3252 // If we're currently evaluating the initializer of this declaration, use that
3253 // in-flight value.
3254 if (Info.EvaluatingDecl == Base) {
3255 Result = Info.EvaluatingDeclValue;
3256 return true;
3257 }
3258
3259 if (isa<ParmVarDecl>(VD)) {
3260 // Assume parameters of a potential constant expression are usable in
3261 // constant expressions.
3262 if (!Info.checkingPotentialConstantExpression() ||
3263 !Info.CurrentCall->Callee ||
3264 !Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
3265 if (Info.getLangOpts().CPlusPlus11) {
3266 Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown)
3267 << VD;
3268 NoteLValueLocation(Info, Base);
3269 } else {
3270 Info.FFDiag(E);
3271 }
3272 }
3273 return false;
3274 }
3275
3276 // Dig out the initializer, and use the declaration which it's attached to.
3277 // FIXME: We should eventually check whether the variable has a reachable
3278 // initializing declaration.
3279 const Expr *Init = VD->getAnyInitializer(VD);
3280 if (!Init) {
3281 // Don't diagnose during potential constant expression checking; an
3282 // initializer might be added later.
3283 if (!Info.checkingPotentialConstantExpression()) {
3284 Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1)
3285 << VD;
3286 NoteLValueLocation(Info, Base);
3287 }
3288 return false;
3289 }
3290
3291 if (Init->isValueDependent()) {
3292 // The DeclRefExpr is not value-dependent, but the variable it refers to
3293 // has a value-dependent initializer. This should only happen in
3294 // constant-folding cases, where the variable is not actually of a suitable
3295 // type for use in a constant expression (otherwise the DeclRefExpr would
3296 // have been value-dependent too), so diagnose that.
3297 assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx))((void)0);
3298 if (!Info.checkingPotentialConstantExpression()) {
3299 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
3300 ? diag::note_constexpr_ltor_non_constexpr
3301 : diag::note_constexpr_ltor_non_integral, 1)
3302 << VD << VD->getType();
3303 NoteLValueLocation(Info, Base);
3304 }
3305 return false;
3306 }
3307
3308 // Check that we can fold the initializer. In C++, we will have already done
3309 // this in the cases where it matters for conformance.
3310 if (!VD->evaluateValue()) {
3311 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
3312 NoteLValueLocation(Info, Base);
3313 return false;
3314 }
3315
3316 // Check that the variable is actually usable in constant expressions. For a
3317 // const integral variable or a reference, we might have a non-constant
3318 // initializer that we can nonetheless evaluate the initializer for. Such
3319 // variables are not usable in constant expressions. In C++98, the
3320 // initializer also syntactically needs to be an ICE.
3321 //
3322 // FIXME: We don't diagnose cases that aren't potentially usable in constant
3323 // expressions here; doing so would regress diagnostics for things like
3324 // reading from a volatile constexpr variable.
3325 if ((Info.getLangOpts().CPlusPlus && !VD->hasConstantInitialization() &&
3326 VD->mightBeUsableInConstantExpressions(Info.Ctx)) ||
3327 ((Info.getLangOpts().CPlusPlus || Info.getLangOpts().OpenCL) &&
3328 !Info.getLangOpts().CPlusPlus11 && !VD->hasICEInitializer(Info.Ctx))) {
3329 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
3330 NoteLValueLocation(Info, Base);
3331 }
3332
3333 // Never use the initializer of a weak variable, not even for constant
3334 // folding. We can't be sure that this is the definition that will be used.
3335 if (VD->isWeak()) {
3336 Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD;
3337 NoteLValueLocation(Info, Base);
3338 return false;
3339 }
3340
3341 Result = VD->getEvaluatedValue();
3342 return true;
3343}
3344
3345/// Get the base index of the given base class within an APValue representing
3346/// the given derived class.
3347static unsigned getBaseIndex(const CXXRecordDecl *Derived,
3348 const CXXRecordDecl *Base) {
3349 Base = Base->getCanonicalDecl();
3350 unsigned Index = 0;
3351 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
3352 E = Derived->bases_end(); I != E; ++I, ++Index) {
3353 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
3354 return Index;
3355 }
3356
3357 llvm_unreachable("base class missing from derived class's bases list")__builtin_unreachable();
3358}
3359
3360/// Extract the value of a character from a string literal.
3361static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
3362 uint64_t Index) {
3363 assert(!isa<SourceLocExpr>(Lit) &&((void)0)
3364 "SourceLocExpr should have already been converted to a StringLiteral")((void)0);
3365
3366 // FIXME: Support MakeStringConstant
3367 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) {
3368 std::string Str;
3369 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str);
3370 assert(Index <= Str.size() && "Index too large")((void)0);
3371 return APSInt::getUnsigned(Str.c_str()[Index]);
3372 }
3373
3374 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
3375 Lit = PE->getFunctionName();
3376 const StringLiteral *S = cast<StringLiteral>(Lit);
3377 const ConstantArrayType *CAT =
3378 Info.Ctx.getAsConstantArrayType(S->getType());
3379 assert(CAT && "string literal isn't an array")((void)0);
3380 QualType CharType = CAT->getElementType();
3381 assert(CharType->isIntegerType() && "unexpected character type")((void)0);
3382
3383 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
3384 CharType->isUnsignedIntegerType());
3385 if (Index < S->getLength())
3386 Value = S->getCodeUnit(Index);
3387 return Value;
3388}
3389
3390// Expand a string literal into an array of characters.
3391//
3392// FIXME: This is inefficient; we should probably introduce something similar
3393// to the LLVM ConstantDataArray to make this cheaper.
3394static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
3395 APValue &Result,
3396 QualType AllocType = QualType()) {
3397 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
3398 AllocType.isNull() ? S->getType() : AllocType);
3399 assert(CAT && "string literal isn't an array")((void)0);
3400 QualType CharType = CAT->getElementType();
3401 assert(CharType->isIntegerType() && "unexpected character type")((void)0);
3402
3403 unsigned Elts = CAT->getSize().getZExtValue();
3404 Result = APValue(APValue::UninitArray(),
3405 std::min(S->getLength(), Elts), Elts);
3406 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
3407 CharType->isUnsignedIntegerType());
3408 if (Result.hasArrayFiller())
3409 Result.getArrayFiller() = APValue(Value);
3410 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
3411 Value = S->getCodeUnit(I);
3412 Result.getArrayInitializedElt(I) = APValue(Value);
3413 }
3414}
3415
3416// Expand an array so that it has more than Index filled elements.
3417static void expandArray(APValue &Array, unsigned Index) {
3418 unsigned Size = Array.getArraySize();
3419 assert(Index < Size)((void)0);
3420
3421 // Always at least double the number of elements for which we store a value.
3422 unsigned OldElts = Array.getArrayInitializedElts();
3423 unsigned NewElts = std::max(Index+1, OldElts * 2);
3424 NewElts = std::min(Size, std::max(NewElts, 8u));
3425
3426 // Copy the data across.
3427 APValue NewValue(APValue::UninitArray(), NewElts, Size);
3428 for (unsigned I = 0; I != OldElts; ++I)
3429 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
3430 for (unsigned I = OldElts; I != NewElts; ++I)
3431 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
3432 if (NewValue.hasArrayFiller())
3433 NewValue.getArrayFiller() = Array.getArrayFiller();
3434 Array.swap(NewValue);
3435}
3436
3437/// Determine whether a type would actually be read by an lvalue-to-rvalue
3438/// conversion. If it's of class type, we may assume that the copy operation
3439/// is trivial. Note that this is never true for a union type with fields
3440/// (because the copy always "reads" the active member) and always true for
3441/// a non-class type.
3442static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD);
3443static bool isReadByLvalueToRvalueConversion(QualType T) {
3444 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3445 return !RD || isReadByLvalueToRvalueConversion(RD);
3446}
3447static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) {
3448 // FIXME: A trivial copy of a union copies the object representation, even if
3449 // the union is empty.
3450 if (RD->isUnion())
3451 return !RD->field_empty();
3452 if (RD->isEmpty())
3453 return false;
3454
3455 for (auto *Field : RD->fields())
3456 if (!Field->isUnnamedBitfield() &&
3457 isReadByLvalueToRvalueConversion(Field->getType()))
3458 return true;
3459
3460 for (auto &BaseSpec : RD->bases())
3461 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
3462 return true;
3463
3464 return false;
3465}
3466
3467/// Diagnose an attempt to read from any unreadable field within the specified
3468/// type, which might be a class type.
3469static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK,
3470 QualType T) {
3471 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3472 if (!RD)
3473 return false;
3474
3475 if (!RD->hasMutableFields())
3476 return false;
3477
3478 for (auto *Field : RD->fields()) {
3479 // If we're actually going to read this field in some way, then it can't
3480 // be mutable. If we're in a union, then assigning to a mutable field
3481 // (even an empty one) can change the active member, so that's not OK.
3482 // FIXME: Add core issue number for the union case.
3483 if (Field->isMutable() &&
3484 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
3485 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field;
3486 Info.Note(Field->getLocation(), diag::note_declared_at);
3487 return true;
3488 }
3489
3490 if (diagnoseMutableFields(Info, E, AK, Field->getType()))
3491 return true;
3492 }
3493
3494 for (auto &BaseSpec : RD->bases())
3495 if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType()))
3496 return true;
3497
3498 // All mutable fields were empty, and thus not actually read.
3499 return false;
3500}
3501
3502static bool lifetimeStartedInEvaluation(EvalInfo &Info,
3503 APValue::LValueBase Base,
3504 bool MutableSubobject = false) {
3505 // A temporary or transient heap allocation we created.
3506 if (Base.getCallIndex() || Base.is<DynamicAllocLValue>())
3507 return true;
3508
3509 switch (Info.IsEvaluatingDecl) {
3510 case EvalInfo::EvaluatingDeclKind::None:
3511 return false;
3512
3513 case EvalInfo::EvaluatingDeclKind::Ctor:
3514 // The variable whose initializer we're evaluating.
3515 if (Info.EvaluatingDecl == Base)
3516 return true;
3517
3518 // A temporary lifetime-extended by the variable whose initializer we're
3519 // evaluating.
3520 if (auto *BaseE = Base.dyn_cast<const Expr *>())
3521 if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE))
3522 return Info.EvaluatingDecl == BaseMTE->getExtendingDecl();
3523 return false;
3524
3525 case EvalInfo::EvaluatingDeclKind::Dtor:
3526 // C++2a [expr.const]p6:
3527 // [during constant destruction] the lifetime of a and its non-mutable
3528 // subobjects (but not its mutable subobjects) [are] considered to start
3529 // within e.
3530 if (MutableSubobject || Base != Info.EvaluatingDecl)
3531 return false;
3532 // FIXME: We can meaningfully extend this to cover non-const objects, but
3533 // we will need special handling: we should be able to access only
3534 // subobjects of such objects that are themselves declared const.
3535 QualType T = getType(Base);
3536 return T.isConstQualified() || T->isReferenceType();
3537 }
3538
3539 llvm_unreachable("unknown evaluating decl kind")__builtin_unreachable();
3540}
3541
3542namespace {
3543/// A handle to a complete object (an object that is not a subobject of
3544/// another object).
3545struct CompleteObject {
3546 /// The identity of the object.
3547 APValue::LValueBase Base;
3548 /// The value of the complete object.
3549 APValue *Value;
3550 /// The type of the complete object.
3551 QualType Type;
3552
3553 CompleteObject() : Value(nullptr) {}
3554 CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type)
3555 : Base(Base), Value(Value), Type(Type) {}
3556
3557 bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const {
3558 // If this isn't a "real" access (eg, if it's just accessing the type
3559 // info), allow it. We assume the type doesn't change dynamically for
3560 // subobjects of constexpr objects (even though we'd hit UB here if it
3561 // did). FIXME: Is this right?
3562 if (!isAnyAccess(AK))
3563 return true;
3564
3565 // In C++14 onwards, it is permitted to read a mutable member whose
3566 // lifetime began within the evaluation.
3567 // FIXME: Should we also allow this in C++11?
3568 if (!Info.getLangOpts().CPlusPlus14)
3569 return false;
3570 return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true);
3571 }
3572
3573 explicit operator bool() const { return !Type.isNull(); }
3574};
3575} // end anonymous namespace
3576
3577static QualType getSubobjectType(QualType ObjType, QualType SubobjType,
3578 bool IsMutable = false) {
3579 // C++ [basic.type.qualifier]p1:
3580 // - A const object is an object of type const T or a non-mutable subobject
3581 // of a const object.
3582 if (ObjType.isConstQualified() && !IsMutable)
3583 SubobjType.addConst();
3584 // - A volatile object is an object of type const T or a subobject of a
3585 // volatile object.
3586 if (ObjType.isVolatileQualified())
3587 SubobjType.addVolatile();
3588 return SubobjType;
3589}
3590
3591/// Find the designated sub-object of an rvalue.
3592template<typename SubobjectHandler>
3593typename SubobjectHandler::result_type
3594findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
3595 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
3596 if (Sub.Invalid)
3597 // A diagnostic will have already been produced.
3598 return handler.failed();
3599 if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) {
3600 if (Info.getLangOpts().CPlusPlus11)
3601 Info.FFDiag(E, Sub.isOnePastTheEnd()
3602 ? diag::note_constexpr_access_past_end
3603 : diag::note_constexpr_access_unsized_array)
3604 << handler.AccessKind;
3605 else
3606 Info.FFDiag(E);
3607 return handler.failed();
3608 }
3609
3610 APValue *O = Obj.Value;
3611 QualType ObjType = Obj.Type;
3612 const FieldDecl *LastField = nullptr;
3613 const FieldDecl *VolatileField = nullptr;
3614
3615 // Walk the designator's path to find the subobject.
3616 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
3617 // Reading an indeterminate value is undefined, but assigning over one is OK.
3618 if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
3619 (O->isIndeterminate() &&
3620 !isValidIndeterminateAccess(handler.AccessKind))) {
3621 if (!Info.checkingPotentialConstantExpression())
3622 Info.FFDiag(E, diag::note_constexpr_access_uninit)
3623 << handler.AccessKind << O->isIndeterminate();
3624 return handler.failed();
3625 }
3626
3627 // C++ [class.ctor]p5, C++ [class.dtor]p5:
3628 // const and volatile semantics are not applied on an object under
3629 // {con,de}struction.
3630 if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) &&
3631 ObjType->isRecordType() &&
3632 Info.isEvaluatingCtorDtor(
3633 Obj.Base, llvm::makeArrayRef(Sub.Entries.begin(),
3634 Sub.Entries.begin() + I)) !=
3635 ConstructionPhase::None) {
3636 ObjType = Info.Ctx.getCanonicalType(ObjType);
3637 ObjType.removeLocalConst();
3638 ObjType.removeLocalVolatile();
3639 }
3640
3641 // If this is our last pass, check that the final object type is OK.
3642 if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) {
3643 // Accesses to volatile objects are prohibited.
3644 if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) {
3645 if (Info.getLangOpts().CPlusPlus) {
3646 int DiagKind;
3647 SourceLocation Loc;
3648 const NamedDecl *Decl = nullptr;
3649 if (VolatileField) {
3650 DiagKind = 2;
3651 Loc = VolatileField->getLocation();
3652 Decl = VolatileField;
3653 } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) {
3654 DiagKind = 1;
3655 Loc = VD->getLocation();
3656 Decl = VD;
3657 } else {
3658 DiagKind = 0;
3659 if (auto *E = Obj.Base.dyn_cast<const Expr *>())
3660 Loc = E->getExprLoc();
3661 }
3662 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3663 << handler.AccessKind << DiagKind << Decl;
3664 Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind;
3665 } else {
3666 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
3667 }
3668 return handler.failed();
3669 }
3670
3671 // If we are reading an object of class type, there may still be more
3672 // things we need to check: if there are any mutable subobjects, we
3673 // cannot perform this read. (This only happens when performing a trivial
3674 // copy or assignment.)
3675 if (ObjType->isRecordType() &&
3676 !Obj.mayAccessMutableMembers(Info, handler.AccessKind) &&
3677 diagnoseMutableFields(Info, E, handler.AccessKind, ObjType))
3678 return handler.failed();
3679 }
3680
3681 if (I == N) {
3682 if (!handler.found(*O, ObjType))
3683 return false;
3684
3685 // If we modified a bit-field, truncate it to the right width.
3686 if (isModification(handler.AccessKind) &&
3687 LastField && LastField->isBitField() &&
3688 !truncateBitfieldValue(Info, E, *O, LastField))
3689 return false;
3690
3691 return true;
3692 }
3693
3694 LastField = nullptr;
3695 if (ObjType->isArrayType()) {
3696 // Next subobject is an array element.
3697 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
3698 assert(CAT && "vla in literal type?")((void)0);
3699 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3700 if (CAT->getSize().ule(Index)) {
3701 // Note, it should not be possible to form a pointer with a valid
3702 // designator which points more than one past the end of the array.
3703 if (Info.getLangOpts().CPlusPlus11)
3704 Info.FFDiag(E, diag::note_constexpr_access_past_end)
3705 << handler.AccessKind;
3706 else
3707 Info.FFDiag(E);
3708 return handler.failed();
3709 }
3710
3711 ObjType = CAT->getElementType();
3712
3713 if (O->getArrayInitializedElts() > Index)
3714 O = &O->getArrayInitializedElt(Index);
3715 else if (!isRead(handler.AccessKind)) {
3716 expandArray(*O, Index);
3717 O = &O->getArrayInitializedElt(Index);
3718 } else
3719 O = &O->getArrayFiller();
3720 } else if (ObjType->isAnyComplexType()) {
3721 // Next subobject is a complex number.
3722 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3723 if (Index > 1) {
3724 if (Info.getLangOpts().CPlusPlus11)
3725 Info.FFDiag(E, diag::note_constexpr_access_past_end)
3726 << handler.AccessKind;
3727 else
3728 Info.FFDiag(E);
3729 return handler.failed();
3730 }
3731
3732 ObjType = getSubobjectType(
3733 ObjType, ObjType->castAs<ComplexType>()->getElementType());
3734
3735 assert(I == N - 1 && "extracting subobject of scalar?")((void)0);
3736 if (O->isComplexInt()) {
3737 return handler.found(Index ? O->getComplexIntImag()
3738 : O->getComplexIntReal(), ObjType);
3739 } else {
3740 assert(O->isComplexFloat())((void)0);
3741 return handler.found(Index ? O->getComplexFloatImag()
3742 : O->getComplexFloatReal(), ObjType);
3743 }
3744 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
3745 if (Field->isMutable() &&
3746 !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) {
3747 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1)
3748 << handler.AccessKind << Field;
3749 Info.Note(Field->getLocation(), diag::note_declared_at);
3750 return handler.failed();
3751 }
3752
3753 // Next subobject is a class, struct or union field.
3754 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
3755 if (RD->isUnion()) {
3756 const FieldDecl *UnionField = O->getUnionField();
3757 if (!UnionField ||
3758 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
3759 if (I == N - 1 && handler.AccessKind == AK_Construct) {
3760 // Placement new onto an inactive union member makes it active.
3761 O->setUnion(Field, APValue());
3762 } else {
3763 // FIXME: If O->getUnionValue() is absent, report that there's no
3764 // active union member rather than reporting the prior active union
3765 // member. We'll need to fix nullptr_t to not use APValue() as its
3766 // representation first.
3767 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
3768 << handler.AccessKind << Field << !UnionField << UnionField;
3769 return handler.failed();
3770 }
3771 }
3772 O = &O->getUnionValue();
3773 } else
3774 O = &O->getStructField(Field->getFieldIndex());
3775
3776 ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable());
3777 LastField = Field;
3778 if (Field->getType().isVolatileQualified())
3779 VolatileField = Field;
3780 } else {
3781 // Next subobject is a base class.
3782 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
3783 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
3784 O = &O->getStructBase(getBaseIndex(Derived, Base));
3785
3786 ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base));
3787 }
3788 }
3789}
3790
3791namespace {
3792struct ExtractSubobjectHandler {
3793 EvalInfo &Info;
3794 const Expr *E;
3795 APValue &Result;
3796 const AccessKinds AccessKind;
3797
3798 typedef bool result_type;
3799 bool failed() { return false; }
3800 bool found(APValue &Subobj, QualType SubobjType) {
3801 Result = Subobj;
3802 if (AccessKind == AK_ReadObjectRepresentation)
3803 return true;
3804 return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result);
3805 }
3806 bool found(APSInt &Value, QualType SubobjType) {
3807 Result = APValue(Value);
3808 return true;
3809 }
3810 bool found(APFloat &Value, QualType SubobjType) {
3811 Result = APValue(Value);
3812 return true;
3813 }
3814};
3815} // end anonymous namespace
3816
3817/// Extract the designated sub-object of an rvalue.
3818static bool extractSubobject(EvalInfo &Info, const Expr *E,
3819 const CompleteObject &Obj,
3820 const SubobjectDesignator &Sub, APValue &Result,
3821 AccessKinds AK = AK_Read) {
3822 assert(AK == AK_Read || AK == AK_ReadObjectRepresentation)((void)0);
3823 ExtractSubobjectHandler Handler = {Info, E, Result, AK};
3824 return findSubobject(Info, E, Obj, Sub, Handler);
3825}
3826
3827namespace {
3828struct ModifySubobjectHandler {
3829 EvalInfo &Info;
3830 APValue &NewVal;
3831 const Expr *E;
3832
3833 typedef bool result_type;
3834 static const AccessKinds AccessKind = AK_Assign;
3835
3836 bool checkConst(QualType QT) {
3837 // Assigning to a const object has undefined behavior.
3838 if (QT.isConstQualified()) {
3839 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3840 return false;
3841 }
3842 return true;
3843 }
3844
3845 bool failed() { return false; }
3846 bool found(APValue &Subobj, QualType SubobjType) {
3847 if (!checkConst(SubobjType))
3848 return false;
3849 // We've been given ownership of NewVal, so just swap it in.
3850 Subobj.swap(NewVal);
3851 return true;
3852 }
3853 bool found(APSInt &Value, QualType SubobjType) {
3854 if (!checkConst(SubobjType))
3855 return false;
3856 if (!NewVal.isInt()) {
3857 // Maybe trying to write a cast pointer value into a complex?
3858 Info.FFDiag(E);
3859 return false;
3860 }
3861 Value = NewVal.getInt();
3862 return true;
3863 }
3864 bool found(APFloat &Value, QualType SubobjType) {
3865 if (!checkConst(SubobjType))
3866 return false;
3867 Value = NewVal.getFloat();
3868 return true;
3869 }
3870};
3871} // end anonymous namespace
3872
3873const AccessKinds ModifySubobjectHandler::AccessKind;
3874
3875/// Update the designated sub-object of an rvalue to the given value.
3876static bool modifySubobject(EvalInfo &Info, const Expr *E,
3877 const CompleteObject &Obj,
3878 const SubobjectDesignator &Sub,
3879 APValue &NewVal) {
3880 ModifySubobjectHandler Handler = { Info, NewVal, E };
3881 return findSubobject(Info, E, Obj, Sub, Handler);
3882}
3883
3884/// Find the position where two subobject designators diverge, or equivalently
3885/// the length of the common initial subsequence.
3886static unsigned FindDesignatorMismatch(QualType ObjType,
3887 const SubobjectDesignator &A,
3888 const SubobjectDesignator &B,
3889 bool &WasArrayIndex) {
3890 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
3891 for (/**/; I != N; ++I) {
3892 if (!ObjType.isNull() &&
3893 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
3894 // Next subobject is an array element.
3895 if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) {
3896 WasArrayIndex = true;
3897 return I;
3898 }
3899 if (ObjType->isAnyComplexType())
3900 ObjType = ObjType->castAs<ComplexType>()->getElementType();
3901 else
3902 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
3903 } else {
3904 if (A.Entries[I].getAsBaseOrMember() !=
3905 B.Entries[I].getAsBaseOrMember()) {
3906 WasArrayIndex = false;
3907 return I;
3908 }
3909 if (const FieldDecl *FD = getAsField(A.Entries[I]))
3910 // Next subobject is a field.
3911 ObjType = FD->getType();
3912 else
3913 // Next subobject is a base class.
3914 ObjType = QualType();
3915 }
3916 }
3917 WasArrayIndex = false;
3918 return I;
3919}
3920
3921/// Determine whether the given subobject designators refer to elements of the
3922/// same array object.
3923static bool AreElementsOfSameArray(QualType ObjType,
3924 const SubobjectDesignator &A,
3925 const SubobjectDesignator &B) {
3926 if (A.Entries.size() != B.Entries.size())
3927 return false;
3928
3929 bool IsArray = A.MostDerivedIsArrayElement;
3930 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
3931 // A is a subobject of the array element.
3932 return false;
3933
3934 // If A (and B) designates an array element, the last entry will be the array
3935 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
3936 // of length 1' case, and the entire path must match.
3937 bool WasArrayIndex;
3938 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
3939 return CommonLength >= A.Entries.size() - IsArray;
3940}
3941
3942/// Find the complete object to which an LValue refers.
3943static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
3944 AccessKinds AK, const LValue &LVal,
3945 QualType LValType) {
3946 if (LVal.InvalidBase) {
3947 Info.FFDiag(E);
3948 return CompleteObject();
3949 }
3950
3951 if (!LVal.Base) {
3952 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
3953 return CompleteObject();
3954 }
3955
3956 CallStackFrame *Frame = nullptr;
3957 unsigned Depth = 0;
3958 if (LVal.getLValueCallIndex()) {
3959 std::tie(Frame, Depth) =
3960 Info.getCallFrameAndDepth(LVal.getLValueCallIndex());
3961 if (!Frame) {
3962 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
3963 << AK << LVal.Base.is<const ValueDecl*>();
3964 NoteLValueLocation(Info, LVal.Base);
3965 return CompleteObject();
3966 }
3967 }
3968
3969 bool IsAccess = isAnyAccess(AK);
3970
3971 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
3972 // is not a constant expression (even if the object is non-volatile). We also
3973 // apply this rule to C++98, in order to conform to the expected 'volatile'
3974 // semantics.
3975 if (isFormalAccess(AK) && LValType.isVolatileQualified()) {
3976 if (Info.getLangOpts().CPlusPlus)
3977 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
3978 << AK << LValType;
3979 else
3980 Info.FFDiag(E);
3981 return CompleteObject();
3982 }
3983
3984 // Compute value storage location and type of base object.
3985 APValue *BaseVal = nullptr;
3986 QualType BaseType = getType(LVal.Base);
3987
3988 if (Info.getLangOpts().CPlusPlus14 && LVal.Base == Info.EvaluatingDecl &&
3989 lifetimeStartedInEvaluation(Info, LVal.Base)) {
3990 // This is the object whose initializer we're evaluating, so its lifetime
3991 // started in the current evaluation.
3992 BaseVal = Info.EvaluatingDeclValue;
3993 } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) {
3994 // Allow reading from a GUID declaration.
3995 if (auto *GD = dyn_cast<MSGuidDecl>(D)) {
3996 if (isModification(AK)) {
3997 // All the remaining cases do not permit modification of the object.
3998 Info.FFDiag(E, diag::note_constexpr_modify_global);
3999 return CompleteObject();
4000 }
4001 APValue &V = GD->getAsAPValue();
4002 if (V.isAbsent()) {
4003 Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
4004 << GD->getType();
4005 return CompleteObject();
4006 }
4007 return CompleteObject(LVal.Base, &V, GD->getType());
4008 }
4009
4010 // Allow reading from template parameter objects.
4011 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D)) {
4012 if (isModification(AK)) {
4013 Info.FFDiag(E, diag::note_constexpr_modify_global);
4014 return CompleteObject();
4015 }
4016 return CompleteObject(LVal.Base, const_cast<APValue *>(&TPO->getValue()),
4017 TPO->getType());
4018 }
4019
4020 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
4021 // In C++11, constexpr, non-volatile variables initialized with constant
4022 // expressions are constant expressions too. Inside constexpr functions,
4023 // parameters are constant expressions even if they're non-const.
4024 // In C++1y, objects local to a constant expression (those with a Frame) are
4025 // both readable and writable inside constant expressions.
4026 // In C, such things can also be folded, although they are not ICEs.
4027 const VarDecl *VD = dyn_cast<VarDecl>(D);
4028 if (VD) {
4029 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
4030 VD = VDef;
4031 }
4032 if (!VD || VD->isInvalidDecl()) {
4033 Info.FFDiag(E);
4034 return CompleteObject();
4035 }
4036
4037 bool IsConstant = BaseType.isConstant(Info.Ctx);
4038
4039 // Unless we're looking at a local variable or argument in a constexpr call,
4040 // the variable we're reading must be const.
4041 if (!Frame) {
4042 if (IsAccess && isa<ParmVarDecl>(VD)) {
4043 // Access of a parameter that's not associated with a frame isn't going
4044 // to work out, but we can leave it to evaluateVarDeclInit to provide a
4045 // suitable diagnostic.
4046 } else if (Info.getLangOpts().CPlusPlus14 &&
4047 lifetimeStartedInEvaluation(Info, LVal.Base)) {
4048 // OK, we can read and modify an object if we're in the process of
4049 // evaluating its initializer, because its lifetime began in this
4050 // evaluation.
4051 } else if (isModification(AK)) {
4052 // All the remaining cases do not permit modification of the object.
4053 Info.FFDiag(E, diag::note_constexpr_modify_global);
4054 return CompleteObject();
4055 } else if (VD->isConstexpr()) {
4056 // OK, we can read this variable.
4057 } else if (BaseType->isIntegralOrEnumerationType()) {
4058 if (!IsConstant) {
4059 if (!IsAccess)
4060 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4061 if (Info.getLangOpts().CPlusPlus) {
4062 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
4063 Info.Note(VD->getLocation(), diag::note_declared_at);
4064 } else {
4065 Info.FFDiag(E);
4066 }
4067 return CompleteObject();
4068 }
4069 } else if (!IsAccess) {
4070 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4071 } else if (IsConstant && Info.checkingPotentialConstantExpression() &&
4072 BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) {
4073 // This variable might end up being constexpr. Don't diagnose it yet.
4074 } else if (IsConstant) {
4075 // Keep evaluating to see what we can do. In particular, we support
4076 // folding of const floating-point types, in order to make static const
4077 // data members of such types (supported as an extension) more useful.
4078 if (Info.getLangOpts().CPlusPlus) {
4079 Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11
4080 ? diag::note_constexpr_ltor_non_constexpr
4081 : diag::note_constexpr_ltor_non_integral, 1)
4082 << VD << BaseType;
4083 Info.Note(VD->getLocation(), diag::note_declared_at);
4084 } else {
4085 Info.CCEDiag(E);
4086 }
4087 } else {
4088 // Never allow reading a non-const value.
4089 if (Info.getLangOpts().CPlusPlus) {
4090 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
4091 ? diag::note_constexpr_ltor_non_constexpr
4092 : diag::note_constexpr_ltor_non_integral, 1)
4093 << VD << BaseType;
4094 Info.Note(VD->getLocation(), diag::note_declared_at);
4095 } else {
4096 Info.FFDiag(E);
4097 }
4098 return CompleteObject();
4099 }
4100 }
4101
4102 if (!evaluateVarDeclInit(Info, E, VD, Frame, LVal.getLValueVersion(), BaseVal))
4103 return CompleteObject();
4104 } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
4105 Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA);
4106 if (!Alloc) {
4107 Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK;
4108 return CompleteObject();
4109 }
4110 return CompleteObject(LVal.Base, &(*Alloc)->Value,
4111 LVal.Base.getDynamicAllocType());
4112 } else {
4113 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4114
4115 if (!Frame) {
4116 if (const MaterializeTemporaryExpr *MTE =
4117 dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) {
4118 assert(MTE->getStorageDuration() == SD_Static &&((void)0)
4119 "should have a frame for a non-global materialized temporary")((void)0);
4120
4121 // C++20 [expr.const]p4: [DR2126]
4122 // An object or reference is usable in constant expressions if it is
4123 // - a temporary object of non-volatile const-qualified literal type
4124 // whose lifetime is extended to that of a variable that is usable
4125 // in constant expressions
4126 //
4127 // C++20 [expr.const]p5:
4128 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
4129 // - a non-volatile glvalue that refers to an object that is usable
4130 // in constant expressions, or
4131 // - a non-volatile glvalue of literal type that refers to a
4132 // non-volatile object whose lifetime began within the evaluation
4133 // of E;
4134 //
4135 // C++11 misses the 'began within the evaluation of e' check and
4136 // instead allows all temporaries, including things like:
4137 // int &&r = 1;
4138 // int x = ++r;
4139 // constexpr int k = r;
4140 // Therefore we use the C++14-onwards rules in C++11 too.
4141 //
4142 // Note that temporaries whose lifetimes began while evaluating a
4143 // variable's constructor are not usable while evaluating the
4144 // corresponding destructor, not even if they're of const-qualified
4145 // types.
4146 if (!MTE->isUsableInConstantExpressions(Info.Ctx) &&
4147 !lifetimeStartedInEvaluation(Info, LVal.Base)) {
4148 if (!IsAccess)
4149 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4150 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
4151 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
4152 return CompleteObject();
4153 }
4154
4155 BaseVal = MTE->getOrCreateValue(false);
4156 assert(BaseVal && "got reference to unevaluated temporary")((void)0);
4157 } else {
4158 if (!IsAccess)
4159 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4160 APValue Val;
4161 LVal.moveInto(Val);
4162 Info.FFDiag(E, diag::note_constexpr_access_unreadable_object)
4163 << AK
4164 << Val.getAsString(Info.Ctx,
4165 Info.Ctx.getLValueReferenceType(LValType));
4166 NoteLValueLocation(Info, LVal.Base);
4167 return CompleteObject();
4168 }
4169 } else {
4170 BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion());
4171 assert(BaseVal && "missing value for temporary")((void)0);
4172 }
4173 }
4174
4175 // In C++14, we can't safely access any mutable state when we might be
4176 // evaluating after an unmodeled side effect. Parameters are modeled as state
4177 // in the caller, but aren't visible once the call returns, so they can be
4178 // modified in a speculatively-evaluated call.
4179 //
4180 // FIXME: Not all local state is mutable. Allow local constant subobjects
4181 // to be read here (but take care with 'mutable' fields).
4182 unsigned VisibleDepth = Depth;
4183 if (llvm::isa_and_nonnull<ParmVarDecl>(
4184 LVal.Base.dyn_cast<const ValueDecl *>()))
4185 ++VisibleDepth;
4186 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
4187 Info.EvalStatus.HasSideEffects) ||
4188 (isModification(AK) && VisibleDepth < Info.SpeculativeEvaluationDepth))
4189 return CompleteObject();
4190
4191 return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType);
4192}
4193
4194/// Perform an lvalue-to-rvalue conversion on the given glvalue. This
4195/// can also be used for 'lvalue-to-lvalue' conversions for looking up the
4196/// glvalue referred to by an entity of reference type.
4197///
4198/// \param Info - Information about the ongoing evaluation.
4199/// \param Conv - The expression for which we are performing the conversion.
4200/// Used for diagnostics.
4201/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
4202/// case of a non-class type).
4203/// \param LVal - The glvalue on which we are attempting to perform this action.
4204/// \param RVal - The produced value will be placed here.
4205/// \param WantObjectRepresentation - If true, we're looking for the object
4206/// representation rather than the value, and in particular,
4207/// there is no requirement that the result be fully initialized.
4208static bool
4209handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type,
4210 const LValue &LVal, APValue &RVal,
4211 bool WantObjectRepresentation = false) {
4212 if (LVal.Designator.Invalid)
4213 return false;
4214
4215 // Check for special cases where there is no existing APValue to look at.
4216 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4217
4218 AccessKinds AK =
4219 WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read;
4220
4221 if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) {
4222 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
4223 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
4224 // initializer until now for such expressions. Such an expression can't be
4225 // an ICE in C, so this only matters for fold.
4226 if (Type.isVolatileQualified()) {
4227 Info.FFDiag(Conv);
4228 return false;
4229 }
4230 APValue Lit;
4231 if (!Evaluate(Lit, Info, CLE->getInitializer()))
4232 return false;
4233 CompleteObject LitObj(LVal.Base, &Lit, Base->getType());
4234 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK);
4235 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
4236 // Special-case character extraction so we don't have to construct an
4237 // APValue for the whole string.
4238 assert(LVal.Designator.Entries.size() <= 1 &&((void)0)
4239 "Can only read characters from string literals")((void)0);
4240 if (LVal.Designator.Entries.empty()) {
4241 // Fail for now for LValue to RValue conversion of an array.
4242 // (This shouldn't show up in C/C++, but it could be triggered by a
4243 // weird EvaluateAsRValue call from a tool.)
4244 Info.FFDiag(Conv);
4245 return false;
4246 }
4247 if (LVal.Designator.isOnePastTheEnd()) {
4248 if (Info.getLangOpts().CPlusPlus11)
4249 Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK;
4250 else
4251 Info.FFDiag(Conv);
4252 return false;
4253 }
4254 uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex();
4255 RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex));
4256 return true;
4257 }
4258 }
4259
4260 CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type);
4261 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK);
4262}
4263
4264/// Perform an assignment of Val to LVal. Takes ownership of Val.
4265static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
4266 QualType LValType, APValue &Val) {
4267 if (LVal.Designator.Invalid)
4268 return false;
4269
4270 if (!Info.getLangOpts().CPlusPlus14) {
4271 Info.FFDiag(E);
4272 return false;
4273 }
4274
4275 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4276 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
4277}
4278
4279namespace {
4280struct CompoundAssignSubobjectHandler {
4281 EvalInfo &Info;
4282 const CompoundAssignOperator *E;
4283 QualType PromotedLHSType;
4284 BinaryOperatorKind Opcode;
4285 const APValue &RHS;
4286
4287 static const AccessKinds AccessKind = AK_Assign;
4288
4289 typedef bool result_type;
4290
4291 bool checkConst(QualType QT) {
4292 // Assigning to a const object has undefined behavior.
4293 if (QT.isConstQualified()) {
4294 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4295 return false;
4296 }
4297 return true;
4298 }
4299
4300 bool failed() { return false; }
4301 bool found(APValue &Subobj, QualType SubobjType) {
4302 switch (Subobj.getKind()) {
4303 case APValue::Int:
4304 return found(Subobj.getInt(), SubobjType);
4305 case APValue::Float:
4306 return found(Subobj.getFloat(), SubobjType);
4307 case APValue::ComplexInt:
4308 case APValue::ComplexFloat:
4309 // FIXME: Implement complex compound assignment.
4310 Info.FFDiag(E);
4311 return false;
4312 case APValue::LValue:
4313 return foundPointer(Subobj, SubobjType);
4314 case APValue::Vector:
4315 return foundVector(Subobj, SubobjType);
4316 default:
4317 // FIXME: can this happen?
4318 Info.FFDiag(E);
4319 return false;
4320 }
4321 }
4322
4323 bool foundVector(APValue &Value, QualType SubobjType) {
4324 if (!checkConst(SubobjType))
4325 return false;
4326
4327 if (!SubobjType->isVectorType()) {
4328 Info.FFDiag(E);
4329 return false;
4330 }
4331 return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS);
4332 }
4333
4334 bool found(APSInt &Value, QualType SubobjType) {
4335 if (!checkConst(SubobjType))
4336 return false;
4337
4338 if (!SubobjType->isIntegerType()) {
4339 // We don't support compound assignment on integer-cast-to-pointer
4340 // values.
4341 Info.FFDiag(E);
4342 return false;
4343 }
4344
4345 if (RHS.isInt()) {
4346 APSInt LHS =
4347 HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value);
4348 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
4349 return false;
4350 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
4351 return true;
4352 } else if (RHS.isFloat()) {
4353 const FPOptions FPO = E->getFPFeaturesInEffect(
4354 Info.Ctx.getLangOpts());
4355 APFloat FValue(0.0);
4356 return HandleIntToFloatCast(Info, E, FPO, SubobjType, Value,
4357 PromotedLHSType, FValue) &&
4358 handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) &&
4359 HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType,
4360 Value);
4361 }
4362
4363 Info.FFDiag(E);
4364 return false;
4365 }
4366 bool found(APFloat &Value, QualType SubobjType) {
4367 return checkConst(SubobjType) &&
4368 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
4369 Value) &&
4370 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
4371 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
4372 }
4373 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4374 if (!checkConst(SubobjType))
4375 return false;
4376
4377 QualType PointeeType;
4378 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4379 PointeeType = PT->getPointeeType();
4380
4381 if (PointeeType.isNull() || !RHS.isInt() ||
4382 (Opcode != BO_Add && Opcode != BO_Sub)) {
4383 Info.FFDiag(E);
4384 return false;
4385 }
4386
4387 APSInt Offset = RHS.getInt();
4388 if (Opcode == BO_Sub)
4389 negateAsSigned(Offset);
4390
4391 LValue LVal;
4392 LVal.setFrom(Info.Ctx, Subobj);
4393 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
4394 return false;
4395 LVal.moveInto(Subobj);
4396 return true;
4397 }
4398};
4399} // end anonymous namespace
4400
4401const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
4402
4403/// Perform a compound assignment of LVal <op>= RVal.
4404static bool handleCompoundAssignment(EvalInfo &Info,
4405 const CompoundAssignOperator *E,
4406 const LValue &LVal, QualType LValType,
4407 QualType PromotedLValType,
4408 BinaryOperatorKind Opcode,
4409 const APValue &RVal) {
4410 if (LVal.Designator.Invalid)
4411 return false;
4412
4413 if (!Info.getLangOpts().CPlusPlus14) {
4414 Info.FFDiag(E);
4415 return false;
4416 }
4417
4418 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4419 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
4420 RVal };
4421 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4422}
4423
4424namespace {
4425struct IncDecSubobjectHandler {
4426 EvalInfo &Info;
4427 const UnaryOperator *E;
4428 AccessKinds AccessKind;
4429 APValue *Old;
4430
4431 typedef bool result_type;
4432
4433 bool checkConst(QualType QT) {
4434 // Assigning to a const object has undefined behavior.
4435 if (QT.isConstQualified()) {
4436 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4437 return false;
4438 }
4439 return true;
4440 }
4441
4442 bool failed() { return false; }
4443 bool found(APValue &Subobj, QualType SubobjType) {
4444 // Stash the old value. Also clear Old, so we don't clobber it later
4445 // if we're post-incrementing a complex.
4446 if (Old) {
4447 *Old = Subobj;
4448 Old = nullptr;
4449 }
4450
4451 switch (Subobj.getKind()) {
4452 case APValue::Int:
4453 return found(Subobj.getInt(), SubobjType);
4454 case APValue::Float:
4455 return found(Subobj.getFloat(), SubobjType);
4456 case APValue::ComplexInt:
4457 return found(Subobj.getComplexIntReal(),
4458 SubobjType->castAs<ComplexType>()->getElementType()
4459 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
4460 case APValue::ComplexFloat:
4461 return found(Subobj.getComplexFloatReal(),
4462 SubobjType->castAs<ComplexType>()->getElementType()
4463 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
4464 case APValue::LValue:
4465 return foundPointer(Subobj, SubobjType);
4466 default:
4467 // FIXME: can this happen?
4468 Info.FFDiag(E);
4469 return false;
4470 }
4471 }
4472 bool found(APSInt &Value, QualType SubobjType) {
4473 if (!checkConst(SubobjType))
4474 return false;
4475
4476 if (!SubobjType->isIntegerType()) {
4477 // We don't support increment / decrement on integer-cast-to-pointer
4478 // values.
4479 Info.FFDiag(E);
4480 return false;
4481 }
4482
4483 if (Old) *Old = APValue(Value);
4484
4485 // bool arithmetic promotes to int, and the conversion back to bool
4486 // doesn't reduce mod 2^n, so special-case it.
4487 if (SubobjType->isBooleanType()) {
4488 if (AccessKind == AK_Increment)
4489 Value = 1;
4490 else
4491 Value = !Value;
4492 return true;
4493 }
4494
4495 bool WasNegative = Value.isNegative();
4496 if (AccessKind == AK_Increment) {
4497 ++Value;
4498
4499 if (!WasNegative && Value.isNegative() && E->canOverflow()) {
4500 APSInt ActualValue(Value, /*IsUnsigned*/true);
4501 return HandleOverflow(Info, E, ActualValue, SubobjType);
4502 }
4503 } else {
4504 --Value;
4505
4506 if (WasNegative && !Value.isNegative() && E->canOverflow()) {
4507 unsigned BitWidth = Value.getBitWidth();
4508 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
4509 ActualValue.setBit(BitWidth);
4510 return HandleOverflow(Info, E, ActualValue, SubobjType);
4511 }
4512 }
4513 return true;
4514 }
4515 bool found(APFloat &Value, QualType SubobjType) {
4516 if (!checkConst(SubobjType))
4517 return false;
4518
4519 if (Old) *Old = APValue(Value);
4520
4521 APFloat One(Value.getSemantics(), 1);
4522 if (AccessKind == AK_Increment)
4523 Value.add(One, APFloat::rmNearestTiesToEven);
4524 else
4525 Value.subtract(One, APFloat::rmNearestTiesToEven);
4526 return true;
4527 }
4528 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4529 if (!checkConst(SubobjType))
4530 return false;
4531
4532 QualType PointeeType;
4533 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4534 PointeeType = PT->getPointeeType();
4535 else {
4536 Info.FFDiag(E);
4537 return false;
4538 }
4539
4540 LValue LVal;
4541 LVal.setFrom(Info.Ctx, Subobj);
4542 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
4543 AccessKind == AK_Increment ? 1 : -1))
4544 return false;
4545 LVal.moveInto(Subobj);
4546 return true;
4547 }
4548};
4549} // end anonymous namespace
4550
4551/// Perform an increment or decrement on LVal.
4552static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
4553 QualType LValType, bool IsIncrement, APValue *Old) {
4554 if (LVal.Designator.Invalid)
4555 return false;
4556
4557 if (!Info.getLangOpts().CPlusPlus14) {
4558 Info.FFDiag(E);
4559 return false;
4560 }
4561
4562 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
4563 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
4564 IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old};
4565 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4566}
4567
4568/// Build an lvalue for the object argument of a member function call.
4569static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
4570 LValue &This) {
4571 if (Object->getType()->isPointerType() && Object->isPRValue())
4572 return EvaluatePointer(Object, This, Info);
4573
4574 if (Object->isGLValue())
4575 return EvaluateLValue(Object, This, Info);
4576
4577 if (Object->getType()->isLiteralType(Info.Ctx))
4578 return EvaluateTemporary(Object, This, Info);
4579
4580 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
4581 return false;
4582}
4583
4584/// HandleMemberPointerAccess - Evaluate a member access operation and build an
4585/// lvalue referring to the result.
4586///
4587/// \param Info - Information about the ongoing evaluation.
4588/// \param LV - An lvalue referring to the base of the member pointer.
4589/// \param RHS - The member pointer expression.
4590/// \param IncludeMember - Specifies whether the member itself is included in
4591/// the resulting LValue subobject designator. This is not possible when
4592/// creating a bound member function.
4593/// \return The field or method declaration to which the member pointer refers,
4594/// or 0 if evaluation fails.
4595static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4596 QualType LVType,
4597 LValue &LV,
4598 const Expr *RHS,
4599 bool IncludeMember = true) {
4600 MemberPtr MemPtr;
4601 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
4602 return nullptr;
4603
4604 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
4605 // member value, the behavior is undefined.
4606 if (!MemPtr.getDecl()) {
4607 // FIXME: Specific diagnostic.
4608 Info.FFDiag(RHS);
4609 return nullptr;
4610 }
4611
4612 if (MemPtr.isDerivedMember()) {
4613 // This is a member of some derived class. Truncate LV appropriately.
4614 // The end of the derived-to-base path for the base object must match the
4615 // derived-to-base path for the member pointer.
4616 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
4617 LV.Designator.Entries.size()) {
4618 Info.FFDiag(RHS);
4619 return nullptr;
4620 }
4621 unsigned PathLengthToMember =
4622 LV.Designator.Entries.size() - MemPtr.Path.size();
4623 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
4624 const CXXRecordDecl *LVDecl = getAsBaseClass(
4625 LV.Designator.Entries[PathLengthToMember + I]);
4626 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
4627 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
4628 Info.FFDiag(RHS);
4629 return nullptr;
4630 }
4631 }
4632
4633 // Truncate the lvalue to the appropriate derived class.
4634 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
4635 PathLengthToMember))
4636 return nullptr;
4637 } else if (!MemPtr.Path.empty()) {
4638 // Extend the LValue path with the member pointer's path.
4639 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
4640 MemPtr.Path.size() + IncludeMember);
4641
4642 // Walk down to the appropriate base class.
4643 if (const PointerType *PT = LVType->getAs<PointerType>())
4644 LVType = PT->getPointeeType();
4645 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
4646 assert(RD && "member pointer access on non-class-type expression")((void)0);
4647 // The first class in the path is that of the lvalue.
4648 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
4649 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
4650 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
4651 return nullptr;
4652 RD = Base;
4653 }
4654 // Finally cast to the class containing the member.
4655 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
4656 MemPtr.getContainingRecord()))
4657 return nullptr;
4658 }
4659
4660 // Add the member. Note that we cannot build bound member functions here.
4661 if (IncludeMember) {
4662 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
4663 if (!HandleLValueMember(Info, RHS, LV, FD))
4664 return nullptr;
4665 } else if (const IndirectFieldDecl *IFD =
4666 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
4667 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
4668 return nullptr;
4669 } else {
4670 llvm_unreachable("can't construct reference to bound member function")__builtin_unreachable();
4671 }
4672 }
4673
4674 return MemPtr.getDecl();
4675}
4676
4677static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4678 const BinaryOperator *BO,
4679 LValue &LV,
4680 bool IncludeMember = true) {
4681 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI)((void)0);
4682
4683 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
4684 if (Info.noteFailure()) {
4685 MemberPtr MemPtr;
4686 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
4687 }
4688 return nullptr;
4689 }
4690
4691 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
4692 BO->getRHS(), IncludeMember);
4693}
4694
4695/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
4696/// the provided lvalue, which currently refers to the base object.
4697static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
4698 LValue &Result) {
4699 SubobjectDesignator &D = Result.Designator;
4700 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
4701 return false;
4702
4703 QualType TargetQT = E->getType();
4704 if (const PointerType *PT = TargetQT->getAs<PointerType>())
4705 TargetQT = PT->getPointeeType();
4706
4707 // Check this cast lands within the final derived-to-base subobject path.
4708 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
4709 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4710 << D.MostDerivedType << TargetQT;
4711 return false;
4712 }
4713
4714 // Check the type of the final cast. We don't need to check the path,
4715 // since a cast can only be formed if the path is unique.
4716 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
4717 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
4718 const CXXRecordDecl *FinalType;
4719 if (NewEntriesSize == D.MostDerivedPathLength)
4720 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
4721 else
4722 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
4723 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
4724 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4725 << D.MostDerivedType << TargetQT;
4726 return false;
4727 }
4728
4729 // Truncate the lvalue to the appropriate derived class.
4730 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
4731}
4732
4733/// Get the value to use for a default-initialized object of type T.
4734/// Return false if it encounters something invalid.
4735static bool getDefaultInitValue(QualType T, APValue &Result) {
4736 bool Success = true;
4737 if (auto *RD = T->getAsCXXRecordDecl()) {
4738 if (RD->isInvalidDecl()) {
4739 Result = APValue();
4740 return false;
4741 }
4742 if (RD->isUnion()) {
4743 Result = APValue((const FieldDecl *)nullptr);
4744 return true;
4745 }
4746 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4747 std::distance(RD->field_begin(), RD->field_end()));
4748
4749 unsigned Index = 0;
4750 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
4751 End = RD->bases_end();
4752 I != End; ++I, ++Index)
4753 Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index));
4754
4755 for (const auto *I : RD->fields()) {
4756 if (I->isUnnamedBitfield())
4757 continue;
4758 Success &= getDefaultInitValue(I->getType(),
4759 Result.getStructField(I->getFieldIndex()));
4760 }
4761 return Success;
4762 }
4763
4764 if (auto *AT =
4765 dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) {
4766 Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue());
4767 if (Result.hasArrayFiller())
4768 Success &=
4769 getDefaultInitValue(AT->getElementType(), Result.getArrayFiller());
4770
4771 return Success;
4772 }
4773
4774 Result = APValue::IndeterminateValue();
4775 return true;
4776}
4777
4778namespace {
4779enum EvalStmtResult {
4780 /// Evaluation failed.
4781 ESR_Failed,
4782 /// Hit a 'return' statement.
4783 ESR_Returned,
4784 /// Evaluation succeeded.
4785 ESR_Succeeded,
4786 /// Hit a 'continue' statement.
4787 ESR_Continue,
4788 /// Hit a 'break' statement.
4789 ESR_Break,
4790 /// Still scanning for 'case' or 'default' statement.
4791 ESR_CaseNotFound
4792};
4793}
4794
4795static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
4796 // We don't need to evaluate the initializer for a static local.
4797 if (!VD->hasLocalStorage())
4798 return true;
4799
4800 LValue Result;
4801 APValue &Val = Info.CurrentCall->createTemporary(VD, VD->getType(),
4802 ScopeKind::Block, Result);
4803
4804 const Expr *InitE = VD->getInit();
4805 if (!InitE) {
4806 if (VD->getType()->isDependentType())
4807 return Info.noteSideEffect();
4808 return getDefaultInitValue(VD->getType(), Val);
4809 }
4810 if (InitE->isValueDependent())
4811 return false;
4812
4813 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
4814 // Wipe out any partially-computed value, to allow tracking that this
4815 // evaluation failed.
4816 Val = APValue();
4817 return false;
4818 }
4819
4820 return true;
4821}
4822
4823static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
4824 bool OK = true;
4825
4826 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
4827 OK &= EvaluateVarDecl(Info, VD);
4828
4829 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
4830 for (auto *BD : DD->bindings())
4831 if (auto *VD = BD->getHoldingVar())
4832 OK &= EvaluateDecl(Info, VD);
4833
4834 return OK;
4835}
4836
4837static bool EvaluateDependentExpr(const Expr *E, EvalInfo &Info) {
4838 assert(E->isValueDependent())((void)0);
4839 if (Info.noteSideEffect())
4840 return true;
4841 assert(E->containsErrors() && "valid value-dependent expression should never "((void)0)
4842 "reach invalid code path.")((void)0);
4843 return false;
4844}
4845
4846/// Evaluate a condition (either a variable declaration or an expression).
4847static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
4848 const Expr *Cond, bool &Result) {
4849 if (Cond->isValueDependent())
4850 return false;
4851 FullExpressionRAII Scope(Info);
4852 if (CondDecl && !EvaluateDecl(Info, CondDecl))
4853 return false;
4854 if (!EvaluateAsBooleanCondition(Cond, Result, Info))
4855 return false;
4856 return Scope.destroy();
4857}
4858
4859namespace {
4860/// A location where the result (returned value) of evaluating a
4861/// statement should be stored.
4862struct StmtResult {
4863 /// The APValue that should be filled in with the returned value.
4864 APValue &Value;
4865 /// The location containing the result, if any (used to support RVO).
4866 const LValue *Slot;
4867};
4868
4869struct TempVersionRAII {
4870 CallStackFrame &Frame;
4871
4872 TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) {
4873 Frame.pushTempVersion();
4874 }
4875
4876 ~TempVersionRAII() {
4877 Frame.popTempVersion();
4878 }
4879};
4880
4881}
4882
4883static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
4884 const Stmt *S,
4885 const SwitchCase *SC = nullptr);
4886
4887/// Evaluate the body of a loop, and translate the result as appropriate.
4888static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
4889 const Stmt *Body,
4890 const SwitchCase *Case = nullptr) {
4891 BlockScopeRAII Scope(Info);
4892
4893 EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case);
4894 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
4895 ESR = ESR_Failed;
4896
4897 switch (ESR) {
4898 case ESR_Break:
4899 return ESR_Succeeded;
4900 case ESR_Succeeded:
4901 case ESR_Continue:
4902 return ESR_Continue;
4903 case ESR_Failed:
4904 case ESR_Returned:
4905 case ESR_CaseNotFound:
4906 return ESR;
4907 }
4908 llvm_unreachable("Invalid EvalStmtResult!")__builtin_unreachable();
4909}
4910
4911/// Evaluate a switch statement.
4912static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
4913 const SwitchStmt *SS) {
4914 BlockScopeRAII Scope(Info);
4915
4916 // Evaluate the switch condition.
4917 APSInt Value;
4918 {
4919 if (const Stmt *Init = SS->getInit()) {
4920 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
4921 if (ESR != ESR_Succeeded) {
4922 if (ESR != ESR_Failed && !Scope.destroy())
4923 ESR = ESR_Failed;
4924 return ESR;
4925 }
4926 }
4927
4928 FullExpressionRAII CondScope(Info);
4929 if (SS->getConditionVariable() &&
4930 !EvaluateDecl(Info, SS->getConditionVariable()))
4931 return ESR_Failed;
4932 if (!EvaluateInteger(SS->getCond(), Value, Info))
4933 return ESR_Failed;
4934 if (!CondScope.destroy())
4935 return ESR_Failed;
4936 }
4937
4938 // Find the switch case corresponding to the value of the condition.
4939 // FIXME: Cache this lookup.
4940 const SwitchCase *Found = nullptr;
4941 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
4942 SC = SC->getNextSwitchCase()) {
4943 if (isa<DefaultStmt>(SC)) {
4944 Found = SC;
4945 continue;
4946 }
4947
4948 const CaseStmt *CS = cast<CaseStmt>(SC);
4949 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
4950 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
4951 : LHS;
4952 if (LHS <= Value && Value <= RHS) {
4953 Found = SC;
4954 break;
4955 }
4956 }
4957
4958 if (!Found)
4959 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
4960
4961 // Search the switch body for the switch case and evaluate it from there.
4962 EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found);
4963 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
4964 return ESR_Failed;
4965
4966 switch (ESR) {
4967 case ESR_Break:
4968 return ESR_Succeeded;
4969 case ESR_Succeeded:
4970 case ESR_Continue:
4971 case ESR_Failed:
4972 case ESR_Returned:
4973 return ESR;
4974 case ESR_CaseNotFound:
4975 // This can only happen if the switch case is nested within a statement
4976 // expression. We have no intention of supporting that.
4977 Info.FFDiag(Found->getBeginLoc(),
4978 diag::note_constexpr_stmt_expr_unsupported);
4979 return ESR_Failed;
4980 }
4981 llvm_unreachable("Invalid EvalStmtResult!")__builtin_unreachable();
4982}
4983
4984// Evaluate a statement.
4985static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
4986 const Stmt *S, const SwitchCase *Case) {
4987 if (!Info.nextStep(S))
4988 return ESR_Failed;
4989
4990 // If we're hunting down a 'case' or 'default' label, recurse through
4991 // substatements until we hit the label.
4992 if (Case) {
4993 switch (S->getStmtClass()) {
4994 case Stmt::CompoundStmtClass:
4995 // FIXME: Precompute which substatement of a compound statement we
4996 // would jump to, and go straight there rather than performing a
4997 // linear scan each time.
4998 case Stmt::LabelStmtClass:
4999 case Stmt::AttributedStmtClass:
5000 case Stmt::DoStmtClass:
5001 break;
5002
5003 case Stmt::CaseStmtClass:
5004 case Stmt::DefaultStmtClass:
5005 if (Case == S)
5006 Case = nullptr;
5007 break;
5008
5009 case Stmt::IfStmtClass: {
5010 // FIXME: Precompute which side of an 'if' we would jump to, and go
5011 // straight there rather than scanning both sides.
5012 const IfStmt *IS = cast<IfStmt>(S);
5013
5014 // Wrap the evaluation in a block scope, in case it's a DeclStmt
5015 // preceded by our switch label.
5016 BlockScopeRAII Scope(Info);
5017
5018 // Step into the init statement in case it brings an (uninitialized)
5019 // variable into scope.
5020 if (const Stmt *Init = IS->getInit()) {
5021 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
5022 if (ESR != ESR_CaseNotFound) {
5023 assert(ESR != ESR_Succeeded)((void)0);
5024 return ESR;
5025 }
5026 }
5027
5028 // Condition variable must be initialized if it exists.
5029 // FIXME: We can skip evaluating the body if there's a condition
5030 // variable, as there can't be any case labels within it.
5031 // (The same is true for 'for' statements.)
5032
5033 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
5034 if (ESR == ESR_Failed)
5035 return ESR;
5036 if (ESR != ESR_CaseNotFound)
5037 return Scope.destroy() ? ESR : ESR_Failed;
5038 if (!IS->getElse())
5039 return ESR_CaseNotFound;
5040
5041 ESR = EvaluateStmt(Result, Info, IS->getElse(), Case);
5042 if (ESR == ESR_Failed)
5043 return ESR;
5044 if (ESR != ESR_CaseNotFound)
5045 return Scope.destroy() ? ESR : ESR_Failed;
5046 return ESR_CaseNotFound;
5047 }
5048
5049 case Stmt::WhileStmtClass: {
5050 EvalStmtResult ESR =
5051 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
5052 if (ESR != ESR_Continue)
5053 return ESR;
5054 break;
5055 }
5056
5057 case Stmt::ForStmtClass: {
5058 const ForStmt *FS = cast<ForStmt>(S);
5059 BlockScopeRAII Scope(Info);
5060
5061 // Step into the init statement in case it brings an (uninitialized)
5062 // variable into scope.
5063 if (const Stmt *Init = FS->getInit()) {
5064 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
5065 if (ESR != ESR_CaseNotFound) {
5066 assert(ESR != ESR_Succeeded)((void)0);
5067 return ESR;
5068 }
5069 }
5070
5071 EvalStmtResult ESR =
5072 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
5073 if (ESR != ESR_Continue)
5074 return ESR;
5075 if (const auto *Inc = FS->getInc()) {
5076 if (Inc->isValueDependent()) {
5077 if (!EvaluateDependentExpr(Inc, Info))
5078 return ESR_Failed;
5079 } else {
5080 FullExpressionRAII IncScope(Info);
5081 if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy())
5082 return ESR_Failed;
5083 }
5084 }
5085 break;
5086 }
5087
5088 case Stmt::DeclStmtClass: {
5089 // Start the lifetime of any uninitialized variables we encounter. They
5090 // might be used by the selected branch of the switch.
5091 const DeclStmt *DS = cast<DeclStmt>(S);
5092 for (const auto *D : DS->decls()) {
5093 if (const auto *VD = dyn_cast<VarDecl>(D)) {
5094 if (VD->hasLocalStorage() && !VD->getInit())
5095 if (!EvaluateVarDecl(Info, VD))
5096 return ESR_Failed;
5097 // FIXME: If the variable has initialization that can't be jumped
5098 // over, bail out of any immediately-surrounding compound-statement
5099 // too. There can't be any case labels here.
5100 }
5101 }
5102 return ESR_CaseNotFound;
5103 }
5104
5105 default:
5106 return ESR_CaseNotFound;
5107 }
5108 }
5109
5110 switch (S->getStmtClass()) {
5111 default:
5112 if (const Expr *E = dyn_cast<Expr>(S)) {
5113 if (E->isValueDependent()) {
5114 if (!EvaluateDependentExpr(E, Info))
5115 return ESR_Failed;
5116 } else {
5117 // Don't bother evaluating beyond an expression-statement which couldn't
5118 // be evaluated.
5119 // FIXME: Do we need the FullExpressionRAII object here?
5120 // VisitExprWithCleanups should create one when necessary.
5121 FullExpressionRAII Scope(Info);
5122 if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy())
5123 return ESR_Failed;
5124 }
5125 return ESR_Succeeded;
5126 }
5127
5128 Info.FFDiag(S->getBeginLoc());
5129 return ESR_Failed;
5130
5131 case Stmt::NullStmtClass:
5132 return ESR_Succeeded;
5133
5134 case Stmt::DeclStmtClass: {
5135 const DeclStmt *DS = cast<DeclStmt>(S);
5136 for (const auto *D : DS->decls()) {
5137 // Each declaration initialization is its own full-expression.
5138 FullExpressionRAII Scope(Info);
5139 if (!EvaluateDecl(Info, D) && !Info.noteFailure())
5140 return ESR_Failed;
5141 if (!Scope.destroy())
5142 return ESR_Failed;
5143 }
5144 return ESR_Succeeded;
5145 }
5146
5147 case Stmt::ReturnStmtClass: {
5148 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
5149 FullExpressionRAII Scope(Info);
5150 if (RetExpr && RetExpr->isValueDependent()) {
5151 EvaluateDependentExpr(RetExpr, Info);
5152 // We know we returned, but we don't know what the value is.
5153 return ESR_Failed;
5154 }
5155 if (RetExpr &&
5156 !(Result.Slot
5157 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
5158 : Evaluate(Result.Value, Info, RetExpr)))
5159 return ESR_Failed;
5160 return Scope.destroy() ? ESR_Returned : ESR_Failed;
5161 }
5162
5163 case Stmt::CompoundStmtClass: {
5164 BlockScopeRAII Scope(Info);
5165
5166 const CompoundStmt *CS = cast<CompoundStmt>(S);
5167 for (const auto *BI : CS->body()) {
5168 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
5169 if (ESR == ESR_Succeeded)
5170 Case = nullptr;
5171 else if (ESR != ESR_CaseNotFound) {
5172 if (ESR != ESR_Failed && !Scope.destroy())
5173 return ESR_Failed;
5174 return ESR;
5175 }
5176 }
5177 if (Case)
5178 return ESR_CaseNotFound;
5179 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5180 }
5181
5182 case Stmt::IfStmtClass: {
5183 const IfStmt *IS = cast<IfStmt>(S);
5184
5185 // Evaluate the condition, as either a var decl or as an expression.
5186 BlockScopeRAII Scope(Info);
5187 if (const Stmt *Init = IS->getInit()) {
5188 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
5189 if (ESR != ESR_Succeeded) {
5190 if (ESR != ESR_Failed && !Scope.destroy())
5191 return ESR_Failed;
5192 return ESR;
5193 }
5194 }
5195 bool Cond;
5196 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
5197 return ESR_Failed;
5198
5199 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
5200 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
5201 if (ESR != ESR_Succeeded) {
5202 if (ESR != ESR_Failed && !Scope.destroy())
5203 return ESR_Failed;
5204 return ESR;
5205 }
5206 }
5207 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5208 }
5209
5210 case Stmt::WhileStmtClass: {
5211 const WhileStmt *WS = cast<WhileStmt>(S);
5212 while (true) {
5213 BlockScopeRAII Scope(Info);
5214 bool Continue;
5215 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
5216 Continue))
5217 return ESR_Failed;
5218 if (!Continue)
5219 break;
5220
5221 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
5222 if (ESR != ESR_Continue) {
5223 if (ESR != ESR_Failed && !Scope.destroy())
5224 return ESR_Failed;
5225 return ESR;
5226 }
5227 if (!Scope.destroy())
5228 return ESR_Failed;
5229 }
5230 return ESR_Succeeded;
5231 }
5232
5233 case Stmt::DoStmtClass: {
5234 const DoStmt *DS = cast<DoStmt>(S);
5235 bool Continue;
5236 do {
5237 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
5238 if (ESR != ESR_Continue)
5239 return ESR;
5240 Case = nullptr;
5241
5242 if (DS->getCond()->isValueDependent()) {
5243 EvaluateDependentExpr(DS->getCond(), Info);
5244 // Bailout as we don't know whether to keep going or terminate the loop.
5245 return ESR_Failed;
5246 }
5247 FullExpressionRAII CondScope(Info);
5248 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) ||
5249 !CondScope.destroy())
5250 return ESR_Failed;
5251 } while (Continue);
5252 return ESR_Succeeded;
5253 }
5254
5255 case Stmt::ForStmtClass: {
5256 const ForStmt *FS = cast<ForStmt>(S);
5257 BlockScopeRAII ForScope(Info);
5258 if (FS->getInit()) {
5259 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
5260 if (ESR != ESR_Succeeded) {
5261 if (ESR != ESR_Failed && !ForScope.destroy())
5262 return ESR_Failed;
5263 return ESR;
5264 }
5265 }
5266 while (true) {
5267 BlockScopeRAII IterScope(Info);
5268 bool Continue = true;
5269 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
5270 FS->getCond(), Continue))
5271 return ESR_Failed;
5272 if (!Continue)
5273 break;
5274
5275 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
5276 if (ESR != ESR_Continue) {
5277 if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy()))
5278 return ESR_Failed;
5279 return ESR;
5280 }
5281
5282 if (const auto *Inc = FS->getInc()) {
5283 if (Inc->isValueDependent()) {
5284 if (!EvaluateDependentExpr(Inc, Info))
5285 return ESR_Failed;
5286 } else {
5287 FullExpressionRAII IncScope(Info);
5288 if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy())
5289 return ESR_Failed;
5290 }
5291 }
5292
5293 if (!IterScope.destroy())
5294 return ESR_Failed;
5295 }
5296 return ForScope.destroy() ? ESR_Succeeded : ESR_Failed;
5297 }
5298
5299 case Stmt::CXXForRangeStmtClass: {
5300 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
5301 BlockScopeRAII Scope(Info);
5302
5303 // Evaluate the init-statement if present.
5304 if (FS->getInit()) {
5305 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
5306 if (ESR != ESR_Succeeded) {
5307 if (ESR != ESR_Failed && !Scope.destroy())
5308 return ESR_Failed;
5309 return ESR;
5310 }
5311 }
5312
5313 // Initialize the __range variable.
5314 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
5315 if (ESR != ESR_Succeeded) {
5316 if (ESR != ESR_Failed && !Scope.destroy())
5317 return ESR_Failed;
5318 return ESR;
5319 }
5320
5321 // Create the __begin and __end iterators.
5322 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
5323 if (ESR != ESR_Succeeded) {
5324 if (ESR != ESR_Failed && !Scope.destroy())
5325 return ESR_Failed;
5326 return ESR;
5327 }
5328 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
5329 if (ESR != ESR_Succeeded) {
5330 if (ESR != ESR_Failed && !Scope.destroy())
5331 return ESR_Failed;
5332 return ESR;
5333 }
5334
5335 while (true) {
5336 // Condition: __begin != __end.
5337 {
5338 if (FS->getCond()->isValueDependent()) {
5339 EvaluateDependentExpr(FS->getCond(), Info);
5340 // We don't know whether to keep going or terminate the loop.
5341 return ESR_Failed;
5342 }
5343 bool Continue = true;
5344 FullExpressionRAII CondExpr(Info);
5345 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
5346 return ESR_Failed;
5347 if (!Continue)
5348 break;
5349 }
5350
5351 // User's variable declaration, initialized by *__begin.
5352 BlockScopeRAII InnerScope(Info);
5353 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
5354 if (ESR != ESR_Succeeded) {
5355 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5356 return ESR_Failed;
5357 return ESR;
5358 }
5359
5360 // Loop body.
5361 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
5362 if (ESR != ESR_Continue) {
5363 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5364 return ESR_Failed;
5365 return ESR;
5366 }
5367 if (FS->getInc()->isValueDependent()) {
5368 if (!EvaluateDependentExpr(FS->getInc(), Info))
5369 return ESR_Failed;
5370 } else {
5371 // Increment: ++__begin
5372 if (!EvaluateIgnoredValue(Info, FS->getInc()))
5373 return ESR_Failed;
5374 }
5375
5376 if (!InnerScope.destroy())
5377 return ESR_Failed;
5378 }
5379
5380 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5381 }
5382
5383 case Stmt::SwitchStmtClass:
5384 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
5385
5386 case Stmt::ContinueStmtClass:
5387 return ESR_Continue;
5388
5389 case Stmt::BreakStmtClass:
5390 return ESR_Break;
5391
5392 case Stmt::LabelStmtClass:
5393 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
5394
5395 case Stmt::AttributedStmtClass:
5396 // As a general principle, C++11 attributes can be ignored without
5397 // any semantic impact.
5398 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
5399 Case);
5400
5401 case Stmt::CaseStmtClass:
5402 case Stmt::DefaultStmtClass:
5403 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
5404 case Stmt::CXXTryStmtClass:
5405 // Evaluate try blocks by evaluating all sub statements.
5406 return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case);
5407 }
5408}
5409
5410/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
5411/// default constructor. If so, we'll fold it whether or not it's marked as
5412/// constexpr. If it is marked as constexpr, we will never implicitly define it,
5413/// so we need special handling.
5414static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
5415 const CXXConstructorDecl *CD,
5416 bool IsValueInitialization) {
5417 if (!CD->isTrivial() || !CD->isDefaultConstructor())
5418 return false;
5419
5420 // Value-initialization does not call a trivial default constructor, so such a
5421 // call is a core constant expression whether or not the constructor is
5422 // constexpr.
5423 if (!CD->isConstexpr() && !IsValueInitialization) {
5424 if (Info.getLangOpts().CPlusPlus11) {
5425 // FIXME: If DiagDecl is an implicitly-declared special member function,
5426 // we should be much more explicit about why it's not constexpr.
5427 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
5428 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
5429 Info.Note(CD->getLocation(), diag::note_declared_at);
5430 } else {
5431 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
5432 }
5433 }
5434 return true;
5435}
5436
5437/// CheckConstexprFunction - Check that a function can be called in a constant
5438/// expression.
5439static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
5440 const FunctionDecl *Declaration,
5441 const FunctionDecl *Definition,
5442 const Stmt *Body) {
5443 // Potential constant expressions can contain calls to declared, but not yet
5444 // defined, constexpr functions.
5445 if (Info.checkingPotentialConstantExpression() && !Definition &&
5446 Declaration->isConstexpr())
5447 return false;
5448
5449 // Bail out if the function declaration itself is invalid. We will
5450 // have produced a relevant diagnostic while parsing it, so just
5451 // note the problematic sub-expression.
5452 if (Declaration->isInvalidDecl()) {
5453 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5454 return false;
5455 }
5456
5457 // DR1872: An instantiated virtual constexpr function can't be called in a
5458 // constant expression (prior to C++20). We can still constant-fold such a
5459 // call.
5460 if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) &&
5461 cast<CXXMethodDecl>(Declaration)->isVirtual())
5462 Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call);
5463
5464 if (Definition && Definition->isInvalidDecl()) {
5465 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5466 return false;
5467 }
5468
5469 // Can we evaluate this function call?
5470 if (Definition && Definition->isConstexpr() && Body)
5471 return true;
5472
5473 if (Info.getLangOpts().CPlusPlus11) {
5474 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
5475
5476 // If this function is not constexpr because it is an inherited
5477 // non-constexpr constructor, diagnose that directly.
5478 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
5479 if (CD && CD->isInheritingConstructor()) {
5480 auto *Inherited = CD->getInheritedConstructor().getConstructor();
5481 if (!Inherited->isConstexpr())
5482 DiagDecl = CD = Inherited;
5483 }
5484
5485 // FIXME: If DiagDecl is an implicitly-declared special member function
5486 // or an inheriting constructor, we should be much more explicit about why
5487 // it's not constexpr.
5488 if (CD && CD->isInheritingConstructor())
5489 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
5490 << CD->getInheritedConstructor().getConstructor()->getParent();
5491 else
5492 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
5493 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
5494 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
5495 } else {
5496 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5497 }
5498 return false;
5499}
5500
5501namespace {
5502struct CheckDynamicTypeHandler {
5503 AccessKinds AccessKind;
5504 typedef bool result_type;
5505 bool failed() { return false; }
5506 bool found(APValue &Subobj, QualType SubobjType) { return true; }
5507 bool found(APSInt &Value, QualType SubobjType) { return true; }
5508 bool found(APFloat &Value, QualType SubobjType) { return true; }
5509};
5510} // end anonymous namespace
5511
5512/// Check that we can access the notional vptr of an object / determine its
5513/// dynamic type.
5514static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
5515 AccessKinds AK, bool Polymorphic) {
5516 if (This.Designator.Invalid)
5517 return false;
5518
5519 CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType());
5520
5521 if (!Obj)
5522 return false;
5523
5524 if (!Obj.Value) {
5525 // The object is not usable in constant expressions, so we can't inspect
5526 // its value to see if it's in-lifetime or what the active union members
5527 // are. We can still check for a one-past-the-end lvalue.
5528 if (This.Designator.isOnePastTheEnd() ||
5529 This.Designator.isMostDerivedAnUnsizedArray()) {
5530 Info.FFDiag(E, This.Designator.isOnePastTheEnd()
5531 ? diag::note_constexpr_access_past_end
5532 : diag::note_constexpr_access_unsized_array)
5533 << AK;
5534 return false;
5535 } else if (Polymorphic) {
5536 // Conservatively refuse to perform a polymorphic operation if we would
5537 // not be able to read a notional 'vptr' value.
5538 APValue Val;
5539 This.moveInto(Val);
5540 QualType StarThisType =
5541 Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx));
5542 Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type)
5543 << AK << Val.getAsString(Info.Ctx, StarThisType);
5544 return false;
5545 }
5546 return true;
5547 }
5548
5549 CheckDynamicTypeHandler Handler{AK};
5550 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
5551}
5552
5553/// Check that the pointee of the 'this' pointer in a member function call is
5554/// either within its lifetime or in its period of construction or destruction.
5555static bool
5556checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E,
5557 const LValue &This,
5558 const CXXMethodDecl *NamedMember) {
5559 return checkDynamicType(
5560 Info, E, This,
5561 isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false);
5562}
5563
5564struct DynamicType {
5565 /// The dynamic class type of the object.
5566 const CXXRecordDecl *Type;
5567 /// The corresponding path length in the lvalue.
5568 unsigned PathLength;
5569};
5570
5571static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator,
5572 unsigned PathLength) {
5573 assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=((void)0)
5574 Designator.Entries.size() && "invalid path length")((void)0);
5575 return (PathLength == Designator.MostDerivedPathLength)
5576 ? Designator.MostDerivedType->getAsCXXRecordDecl()
5577 : getAsBaseClass(Designator.Entries[PathLength - 1]);
5578}
5579
5580/// Determine the dynamic type of an object.
5581static Optional<DynamicType> ComputeDynamicType(EvalInfo &Info, const Expr *E,
5582 LValue &This, AccessKinds AK) {
5583 // If we don't have an lvalue denoting an object of class type, there is no
5584 // meaningful dynamic type. (We consider objects of non-class type to have no
5585 // dynamic type.)
5586 if (!checkDynamicType(Info, E, This, AK, true))
5587 return None;
5588
5589 // Refuse to compute a dynamic type in the presence of virtual bases. This
5590 // shouldn't happen other than in constant-folding situations, since literal
5591 // types can't have virtual bases.
5592 //
5593 // Note that consumers of DynamicType assume that the type has no virtual
5594 // bases, and will need modifications if this restriction is relaxed.
5595 const CXXRecordDecl *Class =
5596 This.Designator.MostDerivedType->getAsCXXRecordDecl();
5597 if (!Class || Class->getNumVBases()) {
5598 Info.FFDiag(E);
5599 return None;
5600 }
5601
5602 // FIXME: For very deep class hierarchies, it might be beneficial to use a
5603 // binary search here instead. But the overwhelmingly common case is that
5604 // we're not in the middle of a constructor, so it probably doesn't matter
5605 // in practice.
5606 ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries;
5607 for (unsigned PathLength = This.Designator.MostDerivedPathLength;
5608 PathLength <= Path.size(); ++PathLength) {
5609 switch (Info.isEvaluatingCtorDtor(This.getLValueBase(),
5610 Path.slice(0, PathLength))) {
5611 case ConstructionPhase::Bases:
5612 case ConstructionPhase::DestroyingBases:
5613 // We're constructing or destroying a base class. This is not the dynamic
5614 // type.
5615 break;
5616
5617 case ConstructionPhase::None:
5618 case ConstructionPhase::AfterBases:
5619 case ConstructionPhase::AfterFields:
5620 case ConstructionPhase::Destroying:
5621 // We've finished constructing the base classes and not yet started
5622 // destroying them again, so this is the dynamic type.
5623 return DynamicType{getBaseClassType(This.Designator, PathLength),
5624 PathLength};
5625 }
5626 }
5627
5628 // CWG issue 1517: we're constructing a base class of the object described by
5629 // 'This', so that object has not yet begun its period of construction and
5630 // any polymorphic operation on it results in undefined behavior.
5631 Info.FFDiag(E);
5632 return None;
5633}
5634
5635/// Perform virtual dispatch.
5636static const CXXMethodDecl *HandleVirtualDispatch(
5637 EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found,
5638 llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) {
5639 Optional<DynamicType> DynType = ComputeDynamicType(
5640 Info, E, This,
5641 isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall);
5642 if (!DynType)
5643 return nullptr;
5644
5645 // Find the final overrider. It must be declared in one of the classes on the
5646 // path from the dynamic type to the static type.
5647 // FIXME: If we ever allow literal types to have virtual base classes, that
5648 // won't be true.
5649 const CXXMethodDecl *Callee = Found;
5650 unsigned PathLength = DynType->PathLength;
5651 for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) {
5652 const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength);
5653 const CXXMethodDecl *Overrider =
5654 Found->getCorrespondingMethodDeclaredInClass(Class, false);
5655 if (Overrider) {
5656 Callee = Overrider;
5657 break;
5658 }
5659 }
5660
5661 // C++2a [class.abstract]p6:
5662 // the effect of making a virtual call to a pure virtual function [...] is
5663 // undefined
5664 if (Callee->isPure()) {
5665 Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee;
5666 Info.Note(Callee->getLocation(), diag::note_declared_at);
5667 return nullptr;
5668 }
5669
5670 // If necessary, walk the rest of the path to determine the sequence of
5671 // covariant adjustment steps to apply.
5672 if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(),
5673 Found->getReturnType())) {
5674 CovariantAdjustmentPath.push_back(Callee->getReturnType());
5675 for (unsigned CovariantPathLength = PathLength + 1;
5676 CovariantPathLength != This.Designator.Entries.size();
5677 ++CovariantPathLength) {
5678 const CXXRecordDecl *NextClass =
5679 getBaseClassType(This.Designator, CovariantPathLength);
5680 const CXXMethodDecl *Next =
5681 Found->getCorrespondingMethodDeclaredInClass(NextClass, false);
5682 if (Next && !Info.Ctx.hasSameUnqualifiedType(
5683 Next->getReturnType(), CovariantAdjustmentPath.back()))
5684 CovariantAdjustmentPath.push_back(Next->getReturnType());
5685 }
5686 if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(),
5687 CovariantAdjustmentPath.back()))
5688 CovariantAdjustmentPath.push_back(Found->getReturnType());
5689 }
5690
5691 // Perform 'this' adjustment.
5692 if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength))
5693 return nullptr;
5694
5695 return Callee;
5696}
5697
5698/// Perform the adjustment from a value returned by a virtual function to
5699/// a value of the statically expected type, which may be a pointer or
5700/// reference to a base class of the returned type.
5701static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E,
5702 APValue &Result,
5703 ArrayRef<QualType> Path) {
5704 assert(Result.isLValue() &&((void)0)
5705 "unexpected kind of APValue for covariant return")((void)0);
5706 if (Result.isNullPointer())
5707 return true;
5708
5709 LValue LVal;
5710 LVal.setFrom(Info.Ctx, Result);
5711
5712 const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl();
5713 for (unsigned I = 1; I != Path.size(); ++I) {
5714 const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl();
5715 assert(OldClass && NewClass && "unexpected kind of covariant return")((void)0);
5716 if (OldClass != NewClass &&
5717 !CastToBaseClass(Info, E, LVal, OldClass, NewClass))
5718 return false;
5719 OldClass = NewClass;
5720 }
5721
5722 LVal.moveInto(Result);
5723 return true;
5724}
5725
5726/// Determine whether \p Base, which is known to be a direct base class of
5727/// \p Derived, is a public base class.
5728static bool isBaseClassPublic(const CXXRecordDecl *Derived,
5729 const CXXRecordDecl *Base) {
5730 for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) {
5731 auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl();
5732 if (BaseClass && declaresSameEntity(BaseClass, Base))
5733 return BaseSpec.getAccessSpecifier() == AS_public;
5734 }
5735 llvm_unreachable("Base is not a direct base of Derived")__builtin_unreachable();
5736}
5737
5738/// Apply the given dynamic cast operation on the provided lvalue.
5739///
5740/// This implements the hard case of dynamic_cast, requiring a "runtime check"
5741/// to find a suitable target subobject.
5742static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E,
5743 LValue &Ptr) {
5744 // We can't do anything with a non-symbolic pointer value.
5745 SubobjectDesignator &D = Ptr.Designator;
5746 if (D.Invalid)
5747 return false;
5748
5749 // C++ [expr.dynamic.cast]p6:
5750 // If v is a null pointer value, the result is a null pointer value.
5751 if (Ptr.isNullPointer() && !E->isGLValue())
5752 return true;
5753
5754 // For all the other cases, we need the pointer to point to an object within
5755 // its lifetime / period of construction / destruction, and we need to know
5756 // its dynamic type.
5757 Optional<DynamicType> DynType =
5758 ComputeDynamicType(Info, E, Ptr, AK_DynamicCast);
5759 if (!DynType)
5760 return false;
5761
5762 // C++ [expr.dynamic.cast]p7:
5763 // If T is "pointer to cv void", then the result is a pointer to the most
5764 // derived object
5765 if (E->getType()->isVoidPointerType())
5766 return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength);
5767
5768 const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl();
5769 assert(C && "dynamic_cast target is not void pointer nor class")((void)0);
5770 CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C));
5771
5772 auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) {
5773 // C++ [expr.dynamic.cast]p9:
5774 if (!E->isGLValue()) {
5775 // The value of a failed cast to pointer type is the null pointer value
5776 // of the required result type.
5777 Ptr.setNull(Info.Ctx, E->getType());
5778 return true;
5779 }
5780
5781 // A failed cast to reference type throws [...] std::bad_cast.
5782 unsigned DiagKind;
5783 if (!Paths && (declaresSameEntity(DynType->Type, C) ||
5784 DynType->Type->isDerivedFrom(C)))
5785 DiagKind = 0;
5786 else if (!Paths || Paths->begin() == Paths->end())
5787 DiagKind = 1;
5788 else if (Paths->isAmbiguous(CQT))
5789 DiagKind = 2;
5790 else {
5791 assert(Paths->front().Access != AS_public && "why did the cast fail?")((void)0);
5792 DiagKind = 3;
5793 }
5794 Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed)
5795 << DiagKind << Ptr.Designator.getType(Info.Ctx)
5796 << Info.Ctx.getRecordType(DynType->Type)
5797 << E->getType().getUnqualifiedType();
5798 return false;
5799 };
5800
5801 // Runtime check, phase 1:
5802 // Walk from the base subobject towards the derived object looking for the
5803 // target type.
5804 for (int PathLength = Ptr.Designator.Entries.size();
5805 PathLength >= (int)DynType->PathLength; --PathLength) {
5806 const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength);
5807 if (declaresSameEntity(Class, C))
5808 return CastToDerivedClass(Info, E, Ptr, Class, PathLength);
5809 // We can only walk across public inheritance edges.
5810 if (PathLength > (int)DynType->PathLength &&
5811 !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1),
5812 Class))
5813 return RuntimeCheckFailed(nullptr);
5814 }
5815
5816 // Runtime check, phase 2:
5817 // Search the dynamic type for an unambiguous public base of type C.
5818 CXXBasePaths Paths(/*FindAmbiguities=*/true,
5819 /*RecordPaths=*/true, /*DetectVirtual=*/false);
5820 if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) &&
5821 Paths.front().Access == AS_public) {
5822 // Downcast to the dynamic type...
5823 if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength))
5824 return false;
5825 // ... then upcast to the chosen base class subobject.
5826 for (CXXBasePathElement &Elem : Paths.front())
5827 if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base))
5828 return false;
5829 return true;
5830 }
5831
5832 // Otherwise, the runtime check fails.
5833 return RuntimeCheckFailed(&Paths);
5834}
5835
5836namespace {
5837struct StartLifetimeOfUnionMemberHandler {
5838 EvalInfo &Info;
5839 const Expr *LHSExpr;
5840 const FieldDecl *Field;
5841 bool DuringInit;
5842 bool Failed = false;
5843 static const AccessKinds AccessKind = AK_Assign;
5844
5845 typedef bool result_type;
5846 bool failed() { return Failed; }
5847 bool found(APValue &Subobj, QualType SubobjType) {
5848 // We are supposed to perform no initialization but begin the lifetime of
5849 // the object. We interpret that as meaning to do what default
5850 // initialization of the object would do if all constructors involved were
5851 // trivial:
5852 // * All base, non-variant member, and array element subobjects' lifetimes
5853 // begin
5854 // * No variant members' lifetimes begin
5855 // * All scalar subobjects whose lifetimes begin have indeterminate values
5856 assert(SubobjType->isUnionType())((void)0);
5857 if (declaresSameEntity(Subobj.getUnionField(), Field)) {
5858 // This union member is already active. If it's also in-lifetime, there's
5859 // nothing to do.
5860 if (Subobj.getUnionValue().hasValue())
5861 return true;
5862 } else if (DuringInit) {
5863 // We're currently in the process of initializing a different union
5864 // member. If we carried on, that initialization would attempt to
5865 // store to an inactive union member, resulting in undefined behavior.
5866 Info.FFDiag(LHSExpr,
5867 diag::note_constexpr_union_member_change_during_init);
5868 return false;
5869 }
5870 APValue Result;
5871 Failed = !getDefaultInitValue(Field->getType(), Result);
5872 Subobj.setUnion(Field, Result);
5873 return true;
5874 }
5875 bool found(APSInt &Value, QualType SubobjType) {
5876 llvm_unreachable("wrong value kind for union object")__builtin_unreachable();
5877 }
5878 bool found(APFloat &Value, QualType SubobjType) {
5879 llvm_unreachable("wrong value kind for union object")__builtin_unreachable();
5880 }
5881};
5882} // end anonymous namespace
5883
5884const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind;
5885
5886/// Handle a builtin simple-assignment or a call to a trivial assignment
5887/// operator whose left-hand side might involve a union member access. If it
5888/// does, implicitly start the lifetime of any accessed union elements per
5889/// C++20 [class.union]5.
5890static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr,
5891 const LValue &LHS) {
5892 if (LHS.InvalidBase || LHS.Designator.Invalid)
5893 return false;
5894
5895 llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths;
5896 // C++ [class.union]p5:
5897 // define the set S(E) of subexpressions of E as follows:
5898 unsigned PathLength = LHS.Designator.Entries.size();
5899 for (const Expr *E = LHSExpr; E != nullptr;) {
5900 // -- If E is of the form A.B, S(E) contains the elements of S(A)...
5901 if (auto *ME = dyn_cast<MemberExpr>(E)) {
5902 auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
5903 // Note that we can't implicitly start the lifetime of a reference,
5904 // so we don't need to proceed any further if we reach one.
5905 if (!FD || FD->getType()->isReferenceType())
5906 break;
5907
5908 // ... and also contains A.B if B names a union member ...
5909 if (FD->getParent()->isUnion()) {
5910 // ... of a non-class, non-array type, or of a class type with a
5911 // trivial default constructor that is not deleted, or an array of
5912 // such types.
5913 auto *RD =
5914 FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
5915 if (!RD || RD->hasTrivialDefaultConstructor())
5916 UnionPathLengths.push_back({PathLength - 1, FD});
5917 }
5918
5919 E = ME->getBase();
5920 --PathLength;
5921 assert(declaresSameEntity(FD,((void)0)
5922 LHS.Designator.Entries[PathLength]((void)0)
5923 .getAsBaseOrMember().getPointer()))((void)0);
5924
5925 // -- If E is of the form A[B] and is interpreted as a built-in array
5926 // subscripting operator, S(E) is [S(the array operand, if any)].
5927 } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
5928 // Step over an ArrayToPointerDecay implicit cast.
5929 auto *Base = ASE->getBase()->IgnoreImplicit();
5930 if (!Base->getType()->isArrayType())
5931 break;
5932
5933 E = Base;
5934 --PathLength;
5935
5936 } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) {
5937 // Step over a derived-to-base conversion.
5938 E = ICE->getSubExpr();
5939 if (ICE->getCastKind() == CK_NoOp)
5940 continue;
5941 if (ICE->getCastKind() != CK_DerivedToBase &&
5942 ICE->getCastKind() != CK_UncheckedDerivedToBase)
5943 break;
5944 // Walk path backwards as we walk up from the base to the derived class.
5945 for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) {
5946 --PathLength;
5947 (void)Elt;
5948 assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),((void)0)
5949 LHS.Designator.Entries[PathLength]((void)0)
5950 .getAsBaseOrMember().getPointer()))((void)0);
5951 }
5952
5953 // -- Otherwise, S(E) is empty.
5954 } else {
5955 break;
5956 }
5957 }
5958
5959 // Common case: no unions' lifetimes are started.
5960 if (UnionPathLengths.empty())
5961 return true;
5962
5963 // if modification of X [would access an inactive union member], an object
5964 // of the type of X is implicitly created
5965 CompleteObject Obj =
5966 findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType());
5967 if (!Obj)
5968 return false;
5969 for (std::pair<unsigned, const FieldDecl *> LengthAndField :
5970 llvm::reverse(UnionPathLengths)) {
5971 // Form a designator for the union object.
5972 SubobjectDesignator D = LHS.Designator;
5973 D.truncate(Info.Ctx, LHS.Base, LengthAndField.first);
5974
5975 bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) ==
5976 ConstructionPhase::AfterBases;
5977 StartLifetimeOfUnionMemberHandler StartLifetime{
5978 Info, LHSExpr, LengthAndField.second, DuringInit};
5979 if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime))
5980 return false;
5981 }
5982
5983 return true;
5984}
5985
5986static bool EvaluateCallArg(const ParmVarDecl *PVD, const Expr *Arg,
5987 CallRef Call, EvalInfo &Info,
5988 bool NonNull = false) {
5989 LValue LV;
5990 // Create the parameter slot and register its destruction. For a vararg
5991 // argument, create a temporary.
5992 // FIXME: For calling conventions that destroy parameters in the callee,
5993 // should we consider performing destruction when the function returns
5994 // instead?
5995 APValue &V = PVD ? Info.CurrentCall->createParam(Call, PVD, LV)
5996 : Info.CurrentCall->createTemporary(Arg, Arg->getType(),
5997 ScopeKind::Call, LV);
5998 if (!EvaluateInPlace(V, Info, LV, Arg))
5999 return false;
6000
6001 // Passing a null pointer to an __attribute__((nonnull)) parameter results in
6002 // undefined behavior, so is non-constant.
6003 if (NonNull && V.isLValue() && V.isNullPointer()) {
6004 Info.CCEDiag(Arg, diag::note_non_null_attribute_failed);
6005 return false;
6006 }
6007
6008 return true;
6009}
6010
6011/// Evaluate the arguments to a function call.
6012static bool EvaluateArgs(ArrayRef<const Expr *> Args, CallRef Call,
6013 EvalInfo &Info, const FunctionDecl *Callee,
6014 bool RightToLeft = false) {
6015 bool Success = true;
6016 llvm::SmallBitVector ForbiddenNullArgs;
6017 if (Callee->hasAttr<NonNullAttr>()) {
6018 ForbiddenNullArgs.resize(Args.size());
6019 for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) {
6020 if (!Attr->args_size()) {
6021 ForbiddenNullArgs.set();
6022 break;
6023 } else
6024 for (auto Idx : Attr->args()) {
6025 unsigned ASTIdx = Idx.getASTIndex();
6026 if (ASTIdx >= Args.size())
6027 continue;
6028 ForbiddenNullArgs[ASTIdx] = 1;
6029 }
6030 }
6031 }
6032 for (unsigned I = 0; I < Args.size(); I++) {
6033 unsigned Idx = RightToLeft ? Args.size() - I - 1 : I;
6034 const ParmVarDecl *PVD =
6035 Idx < Callee->getNumParams() ? Callee->getParamDecl(Idx) : nullptr;
6036 bool NonNull = !ForbiddenNullArgs.empty() && ForbiddenNullArgs[Idx];
6037 if (!EvaluateCallArg(PVD, Args[Idx], Call, Info, NonNull)) {
6038 // If we're checking for a potential constant expression, evaluate all
6039 // initializers even if some of them fail.
6040 if (!Info.noteFailure())
6041 return false;
6042 Success = false;
6043 }
6044 }
6045 return Success;
6046}
6047
6048/// Perform a trivial copy from Param, which is the parameter of a copy or move
6049/// constructor or assignment operator.
6050static bool handleTrivialCopy(EvalInfo &Info, const ParmVarDecl *Param,
6051 const Expr *E, APValue &Result,
6052 bool CopyObjectRepresentation) {
6053 // Find the reference argument.
6054 CallStackFrame *Frame = Info.CurrentCall;
6055 APValue *RefValue = Info.getParamSlot(Frame->Arguments, Param);
6056 if (!RefValue) {
6057 Info.FFDiag(E);
6058 return false;
6059 }
6060
6061 // Copy out the contents of the RHS object.
6062 LValue RefLValue;
6063 RefLValue.setFrom(Info.Ctx, *RefValue);
6064 return handleLValueToRValueConversion(
6065 Info, E, Param->getType().getNonReferenceType(), RefLValue, Result,
6066 CopyObjectRepresentation);
6067}
6068
6069/// Evaluate a function call.
6070static bool HandleFunctionCall(SourceLocation CallLoc,
6071 const FunctionDecl *Callee, const LValue *This,
6072 ArrayRef<const Expr *> Args, CallRef Call,
6073 const Stmt *Body, EvalInfo &Info,
6074 APValue &Result, const LValue *ResultSlot) {
6075 if (!Info.CheckCallLimit(CallLoc))
6076 return false;
6077
6078 CallStackFrame Frame(Info, CallLoc, Callee, This, Call);
6079
6080 // For a trivial copy or move assignment, perform an APValue copy. This is
6081 // essential for unions, where the operations performed by the assignment
6082 // operator cannot be represented as statements.
6083 //
6084 // Skip this for non-union classes with no fields; in that case, the defaulted
6085 // copy/move does not actually read the object.
6086 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
6087 if (MD && MD->isDefaulted() &&
6088 (MD->getParent()->isUnion() ||
6089 (MD->isTrivial() &&
6090 isReadByLvalueToRvalueConversion(MD->getParent())))) {
6091 assert(This &&((void)0)
6092 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()))((void)0);
6093 APValue RHSValue;
6094 if (!handleTrivialCopy(Info, MD->getParamDecl(0), Args[0], RHSValue,
6095 MD->getParent()->isUnion()))
6096 return false;
6097 if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() &&
6098 !HandleUnionActiveMemberChange(Info, Args[0], *This))
6099 return false;
6100 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(),
6101 RHSValue))
6102 return false;
6103 This->moveInto(Result);
6104 return true;
6105 } else if (MD && isLambdaCallOperator(MD)) {
6106 // We're in a lambda; determine the lambda capture field maps unless we're
6107 // just constexpr checking a lambda's call operator. constexpr checking is
6108 // done before the captures have been added to the closure object (unless
6109 // we're inferring constexpr-ness), so we don't have access to them in this
6110 // case. But since we don't need the captures to constexpr check, we can
6111 // just ignore them.
6112 if (!Info.checkingPotentialConstantExpression())
6113 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields,
6114 Frame.LambdaThisCaptureField);
6115 }
6116
6117 StmtResult Ret = {Result, ResultSlot};
6118 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
6119 if (ESR == ESR_Succeeded) {
6120 if (Callee->getReturnType()->isVoidType())
6121 return true;
6122 Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return);
6123 }
6124 return ESR == ESR_Returned;
6125}
6126
6127/// Evaluate a constructor call.
6128static bool HandleConstructorCall(const Expr *E, const LValue &This,
6129 CallRef Call,
6130 const CXXConstructorDecl *Definition,
6131 EvalInfo &Info, APValue &Result) {
6132 SourceLocation CallLoc = E->getExprLoc();
6133 if (!Info.CheckCallLimit(CallLoc))
6134 return false;
6135
6136 const CXXRecordDecl *RD = Definition->getParent();
6137 if (RD->getNumVBases()) {
6138 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
6139 return false;
6140 }
6141
6142 EvalInfo::EvaluatingConstructorRAII EvalObj(
6143 Info,
6144 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
6145 RD->getNumBases());
6146 CallStackFrame Frame(Info, CallLoc, Definition, &This, Call);
6147
6148 // FIXME: Creating an APValue just to hold a nonexistent return value is
6149 // wasteful.
6150 APValue RetVal;
6151 StmtResult Ret = {RetVal, nullptr};
6152
6153 // If it's a delegating constructor, delegate.
6154 if (Definition->isDelegatingConstructor()) {
6155 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
6156 if ((*I)->getInit()->isValueDependent()) {
6157 if (!EvaluateDependentExpr((*I)->getInit(), Info))
6158 return false;
6159 } else {
6160 FullExpressionRAII InitScope(Info);
6161 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) ||
6162 !InitScope.destroy())
6163 return false;
6164 }
6165 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
6166 }
6167
6168 // For a trivial copy or move constructor, perform an APValue copy. This is
6169 // essential for unions (or classes with anonymous union members), where the
6170 // operations performed by the constructor cannot be represented by
6171 // ctor-initializers.
6172 //
6173 // Skip this for empty non-union classes; we should not perform an
6174 // lvalue-to-rvalue conversion on them because their copy constructor does not
6175 // actually read them.
6176 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
6177 (Definition->getParent()->isUnion() ||
6178 (Definition->isTrivial() &&
6179 isReadByLvalueToRvalueConversion(Definition->getParent())))) {
6180 return handleTrivialCopy(Info, Definition->getParamDecl(0), E, Result,
6181 Definition->getParent()->isUnion());
6182 }
6183
6184 // Reserve space for the struct members.
6185 if (!Result.hasValue()) {
6186 if (!RD->isUnion())
6187 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
6188 std::distance(RD->field_begin(), RD->field_end()));
6189 else
6190 // A union starts with no active member.
6191 Result = APValue((const FieldDecl*)nullptr);
6192 }
6193
6194 if (RD->isInvalidDecl()) return false;
6195 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6196
6197 // A scope for temporaries lifetime-extended by reference members.
6198 BlockScopeRAII LifetimeExtendedScope(Info);
6199
6200 bool Success = true;
6201 unsigned BasesSeen = 0;
6202#ifndef NDEBUG1
6203 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
6204#endif
6205 CXXRecordDecl::field_iterator FieldIt = RD->field_begin();
6206 auto SkipToField = [&](FieldDecl *FD, bool Indirect) {
6207 // We might be initializing the same field again if this is an indirect
6208 // field initialization.
6209 if (FieldIt == RD->field_end() ||
6210 FieldIt->getFieldIndex() > FD->getFieldIndex()) {
6211 assert(Indirect && "fields out of order?")((void)0);
6212 return;
6213 }
6214
6215 // Default-initialize any fields with no explicit initializer.
6216 for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) {
6217 assert(FieldIt != RD->field_end() && "missing field?")((void)0);
6218 if (!FieldIt->isUnnamedBitfield())
6219 Success &= getDefaultInitValue(
6220 FieldIt->getType(),
6221 Result.getStructField(FieldIt->getFieldIndex()));
6222 }
6223 ++FieldIt;
6224 };
6225 for (const auto *I : Definition->inits()) {
6226 LValue Subobject = This;
6227 LValue SubobjectParent = This;
6228 APValue *Value = &Result;
6229
6230 // Determine the subobject to initialize.
6231 FieldDecl *FD = nullptr;
6232 if (I->isBaseInitializer()) {
6233 QualType BaseType(I->getBaseClass(), 0);
6234#ifndef NDEBUG1
6235 // Non-virtual base classes are initialized in the order in the class
6236 // definition. We have already checked for virtual base classes.
6237 assert(!BaseIt->isVirtual() && "virtual base for literal type")((void)0);
6238 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&((void)0)
6239 "base class initializers not in expected order")((void)0);
6240 ++BaseIt;
6241#endif
6242 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
6243 BaseType->getAsCXXRecordDecl(), &Layout))
6244 return false;
6245 Value = &Result.getStructBase(BasesSeen++);
6246 } else if ((FD = I->getMember())) {
6247 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
6248 return false;
6249 if (RD->isUnion()) {
6250 Result = APValue(FD);
6251 Value = &Result.getUnionValue();
6252 } else {
6253 SkipToField(FD, false);
6254 Value = &Result.getStructField(FD->getFieldIndex());
6255 }
6256 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
6257 // Walk the indirect field decl's chain to find the object to initialize,
6258 // and make sure we've initialized every step along it.
6259 auto IndirectFieldChain = IFD->chain();
6260 for (auto *C : IndirectFieldChain) {
6261 FD = cast<FieldDecl>(C);
6262 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
6263 // Switch the union field if it differs. This happens if we had
6264 // preceding zero-initialization, and we're now initializing a union
6265 // subobject other than the first.
6266 // FIXME: In this case, the values of the other subobjects are
6267 // specified, since zero-initialization sets all padding bits to zero.
6268 if (!Value->hasValue() ||
6269 (Value->isUnion() && Value->getUnionField() != FD)) {
6270 if (CD->isUnion())
6271 *Value = APValue(FD);
6272 else
6273 // FIXME: This immediately starts the lifetime of all members of
6274 // an anonymous struct. It would be preferable to strictly start
6275 // member lifetime in initialization order.
6276 Success &= getDefaultInitValue(Info.Ctx.getRecordType(CD), *Value);
6277 }
6278 // Store Subobject as its parent before updating it for the last element
6279 // in the chain.
6280 if (C == IndirectFieldChain.back())
6281 SubobjectParent = Subobject;
6282 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
6283 return false;
6284 if (CD->isUnion())
6285 Value = &Value->getUnionValue();
6286 else {
6287 if (C == IndirectFieldChain.front() && !RD->isUnion())
6288 SkipToField(FD, true);
6289 Value = &Value->getStructField(FD->getFieldIndex());
6290 }
6291 }
6292 } else {
6293 llvm_unreachable("unknown base initializer kind")__builtin_unreachable();
6294 }
6295
6296 // Need to override This for implicit field initializers as in this case
6297 // This refers to innermost anonymous struct/union containing initializer,
6298 // not to currently constructed class.
6299 const Expr *Init = I->getInit();
6300 if (Init->isValueDependent()) {
6301 if (!EvaluateDependentExpr(Init, Info))
6302 return false;
6303 } else {
6304 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
6305 isa<CXXDefaultInitExpr>(Init));
6306 FullExpressionRAII InitScope(Info);
6307 if (!EvaluateInPlace(*Value, Info, Subobject, Init) ||
6308 (FD && FD->isBitField() &&
6309 !truncateBitfieldValue(Info, Init, *Value, FD))) {
6310 // If we're checking for a potential constant expression, evaluate all
6311 // initializers even if some of them fail.
6312 if (!Info.noteFailure())
6313 return false;
6314 Success = false;
6315 }
6316 }
6317
6318 // This is the point at which the dynamic type of the object becomes this
6319 // class type.
6320 if (I->isBaseInitializer() && BasesSeen == RD->getNumBases())
6321 EvalObj.finishedConstructingBases();
6322 }
6323
6324 // Default-initialize any remaining fields.
6325 if (!RD->isUnion()) {
6326 for (; FieldIt != RD->field_end(); ++FieldIt) {
6327 if (!FieldIt->isUnnamedBitfield())
6328 Success &= getDefaultInitValue(
6329 FieldIt->getType(),
6330 Result.getStructField(FieldIt->getFieldIndex()));
6331 }
6332 }
6333
6334 EvalObj.finishedConstructingFields();
6335
6336 return Success &&
6337 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed &&
6338 LifetimeExtendedScope.destroy();
6339}
6340
6341static bool HandleConstructorCall(const Expr *E, const LValue &This,
6342 ArrayRef<const Expr*> Args,
6343 const CXXConstructorDecl *Definition,
6344 EvalInfo &Info, APValue &Result) {
6345 CallScopeRAII CallScope(Info);
6346 CallRef Call = Info.CurrentCall->createCall(Definition);
6347 if (!EvaluateArgs(Args, Call, Info, Definition))
6348 return false;
6349
6350 return HandleConstructorCall(E, This, Call, Definition, Info, Result) &&
6351 CallScope.destroy();
6352}
6353
6354static bool HandleDestructionImpl(EvalInfo &Info, SourceLocation CallLoc,
6355 const LValue &This, APValue &Value,
6356 QualType T) {
6357 // Objects can only be destroyed while they're within their lifetimes.
6358 // FIXME: We have no representation for whether an object of type nullptr_t
6359 // is in its lifetime; it usually doesn't matter. Perhaps we should model it
6360 // as indeterminate instead?
6361 if (Value.isAbsent() && !T->isNullPtrType()) {
6362 APValue Printable;
6363 This.moveInto(Printable);
6364 Info.FFDiag(CallLoc, diag::note_constexpr_destroy_out_of_lifetime)
6365 << Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T));
6366 return false;
6367 }
6368
6369 // Invent an expression for location purposes.
6370 // FIXME: We shouldn't need to do this.
6371 OpaqueValueExpr LocE(CallLoc, Info.Ctx.IntTy, VK_PRValue);
6372
6373 // For arrays, destroy elements right-to-left.
6374 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) {
6375 uint64_t Size = CAT->getSize().getZExtValue();
6376 QualType ElemT = CAT->getElementType();
6377
6378 LValue ElemLV = This;
6379 ElemLV.addArray(Info, &LocE, CAT);
6380 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size))
6381 return false;
6382
6383 // Ensure that we have actual array elements available to destroy; the
6384 // destructors might mutate the value, so we can't run them on the array
6385 // filler.
6386 if (Size && Size > Value.getArrayInitializedElts())
6387 expandArray(Value, Value.getArraySize() - 1);
6388
6389 for (; Size != 0; --Size) {
6390 APValue &Elem = Value.getArrayInitializedElt(Size - 1);
6391 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) ||
6392 !HandleDestructionImpl(Info, CallLoc, ElemLV, Elem, ElemT))
6393 return false;
6394 }
6395
6396 // End the lifetime of this array now.
6397 Value = APValue();
6398 return true;
6399 }
6400
6401 const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
6402 if (!RD) {
6403 if (T.isDestructedType()) {
6404 Info.FFDiag(CallLoc, diag::note_constexpr_unsupported_destruction) << T;
6405 return false;
6406 }
6407
6408 Value = APValue();
6409 return true;
6410 }
6411
6412 if (RD->getNumVBases()) {
6413 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
6414 return false;
6415 }
6416
6417 const CXXDestructorDecl *DD = RD->getDestructor();
6418 if (!DD && !RD->hasTrivialDestructor()) {
6419 Info.FFDiag(CallLoc);
6420 return false;
6421 }
6422
6423 if (!DD || DD->isTrivial() ||
6424 (RD->isAnonymousStructOrUnion() && RD->isUnion())) {
6425 // A trivial destructor just ends the lifetime of the object. Check for
6426 // this case before checking for a body, because we might not bother
6427 // building a body for a trivial destructor. Note that it doesn't matter
6428 // whether the destructor is constexpr in this case; all trivial
6429 // destructors are constexpr.
6430 //
6431 // If an anonymous union would be destroyed, some enclosing destructor must
6432 // have been explicitly defined, and the anonymous union destruction should
6433 // have no effect.
6434 Value = APValue();
6435 return true;
6436 }
6437
6438 if (!Info.CheckCallLimit(CallLoc))
6439 return false;
6440
6441 const FunctionDecl *Definition = nullptr;
6442 const Stmt *Body = DD->getBody(Definition);
6443
6444 if (!CheckConstexprFunction(Info, CallLoc, DD, Definition, Body))
6445 return false;
6446
6447 CallStackFrame Frame(Info, CallLoc, Definition, &This, CallRef());
6448
6449 // We're now in the period of destruction of this object.
6450 unsigned BasesLeft = RD->getNumBases();
6451 EvalInfo::EvaluatingDestructorRAII EvalObj(
6452 Info,
6453 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries});
6454 if (!EvalObj.DidInsert) {
6455 // C++2a [class.dtor]p19:
6456 // the behavior is undefined if the destructor is invoked for an object
6457 // whose lifetime has ended
6458 // (Note that formally the lifetime ends when the period of destruction
6459 // begins, even though certain uses of the object remain valid until the
6460 // period of destruction ends.)
6461 Info.FFDiag(CallLoc, diag::note_constexpr_double_destroy);
6462 return false;
6463 }
6464
6465 // FIXME: Creating an APValue just to hold a nonexistent return value is
6466 // wasteful.
6467 APValue RetVal;
6468 StmtResult Ret = {RetVal, nullptr};
6469 if (EvaluateStmt(Ret, Info, Definition->getBody()) == ESR_Failed)
6470 return false;
6471
6472 // A union destructor does not implicitly destroy its members.
6473 if (RD->isUnion())
6474 return true;
6475
6476 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6477
6478 // We don't have a good way to iterate fields in reverse, so collect all the
6479 // fields first and then walk them backwards.
6480 SmallVector<FieldDecl*, 16> Fields(RD->field_begin(), RD->field_end());
6481 for (const FieldDecl *FD : llvm::reverse(Fields)) {
6482 if (FD->isUnnamedBitfield())
6483 continue;
6484
6485 LValue Subobject = This;
6486 if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout))
6487 return false;
6488
6489 APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex());
6490 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
6491 FD->getType()))
6492 return false;
6493 }
6494
6495 if (BasesLeft != 0)
6496 EvalObj.startedDestroyingBases();
6497
6498 // Destroy base classes in reverse order.
6499 for (const CXXBaseSpecifier &Base : llvm::reverse(RD->bases())) {
6500 --BasesLeft;
6501
6502 QualType BaseType = Base.getType();
6503 LValue Subobject = This;
6504 if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD,
6505 BaseType->getAsCXXRecordDecl(), &Layout))
6506 return false;
6507
6508 APValue *SubobjectValue = &Value.getStructBase(BasesLeft);
6509 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
6510 BaseType))
6511 return false;
6512 }
6513 assert(BasesLeft == 0 && "NumBases was wrong?")((void)0);
6514
6515 // The period of destruction ends now. The object is gone.
6516 Value = APValue();
6517 return true;
6518}
6519
6520namespace {
6521struct DestroyObjectHandler {
6522 EvalInfo &Info;
6523 const Expr *E;
6524 const LValue &This;
6525 const AccessKinds AccessKind;
6526
6527 typedef bool result_type;
6528 bool failed() { return false; }
6529 bool found(APValue &Subobj, QualType SubobjType) {
6530 return HandleDestructionImpl(Info, E->getExprLoc(), This, Subobj,
6531 SubobjType);
6532 }
6533 bool found(APSInt &Value, QualType SubobjType) {
6534 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6535 return false;
6536 }
6537 bool found(APFloat &Value, QualType SubobjType) {
6538 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6539 return false;
6540 }
6541};
6542}
6543
6544/// Perform a destructor or pseudo-destructor call on the given object, which
6545/// might in general not be a complete object.
6546static bool HandleDestruction(EvalInfo &Info, const Expr *E,
6547 const LValue &This, QualType ThisType) {
6548 CompleteObject Obj = findCompleteObject(Info, E, AK_Destroy, This, ThisType);
6549 DestroyObjectHandler Handler = {Info, E, This, AK_Destroy};
6550 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
6551}
6552
6553/// Destroy and end the lifetime of the given complete object.
6554static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
6555 APValue::LValueBase LVBase, APValue &Value,
6556 QualType T) {
6557 // If we've had an unmodeled side-effect, we can't rely on mutable state
6558 // (such as the object we're about to destroy) being correct.
6559 if (Info.EvalStatus.HasSideEffects)
6560 return false;
6561
6562 LValue LV;
6563 LV.set({LVBase});
6564 return HandleDestructionImpl(Info, Loc, LV, Value, T);
6565}
6566
6567/// Perform a call to 'perator new' or to `__builtin_operator_new'.
6568static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
6569 LValue &Result) {
6570 if (Info.checkingPotentialConstantExpression() ||
6571 Info.SpeculativeEvaluationDepth)
6572 return false;
6573
6574 // This is permitted only within a call to std::allocator<T>::allocate.
6575 auto Caller = Info.getStdAllocatorCaller("allocate");
6576 if (!Caller) {
6577 Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20
6578 ? diag::note_constexpr_new_untyped
6579 : diag::note_constexpr_new);
6580 return false;
6581 }
6582
6583 QualType ElemType = Caller.ElemType;
6584 if (ElemType->isIncompleteType() || ElemType->isFunctionType()) {
6585 Info.FFDiag(E->getExprLoc(),
6586 diag::note_constexpr_new_not_complete_object_type)
6587 << (ElemType->isIncompleteType() ? 0 : 1) << ElemType;
6588 return false;
6589 }
6590
6591 APSInt ByteSize;
6592 if (!EvaluateInteger(E->getArg(0), ByteSize, Info))
6593 return false;
6594 bool IsNothrow = false;
6595 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) {
6596 EvaluateIgnoredValue(Info, E->getArg(I));
6597 IsNothrow |= E->getType()->isNothrowT();
6598 }
6599
6600 CharUnits ElemSize;
6601 if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize))
6602 return false;
6603 APInt Size, Remainder;
6604 APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity());
6605 APInt::udivrem(ByteSize, ElemSizeAP, Size, Remainder);
6606 if (Remainder != 0) {
6607 // This likely indicates a bug in the implementation of 'std::allocator'.
6608 Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size)
6609 << ByteSize << APSInt(ElemSizeAP, true) << ElemType;
6610 return false;
6611 }
6612
6613 if (ByteSize.getActiveBits() > ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
6614 if (IsNothrow) {
6615 Result.setNull(Info.Ctx, E->getType());
6616 return true;
6617 }
6618
6619 Info.FFDiag(E, diag::note_constexpr_new_too_large) << APSInt(Size, true);
6620 return false;
6621 }
6622
6623 QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr,
6624 ArrayType::Normal, 0);
6625 APValue *Val = Info.createHeapAlloc(E, AllocType, Result);
6626 *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
6627 Result.addArray(Info, E, cast<ConstantArrayType>(AllocType));
6628 return true;
6629}
6630
6631static bool hasVirtualDestructor(QualType T) {
6632 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6633 if (CXXDestructorDecl *DD = RD->getDestructor())
6634 return DD->isVirtual();
6635 return false;
6636}
6637
6638static const FunctionDecl *getVirtualOperatorDelete(QualType T) {
6639 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6640 if (CXXDestructorDecl *DD = RD->getDestructor())
6641 return DD->isVirtual() ? DD->getOperatorDelete() : nullptr;
6642 return nullptr;
6643}
6644
6645/// Check that the given object is a suitable pointer to a heap allocation that
6646/// still exists and is of the right kind for the purpose of a deletion.
6647///
6648/// On success, returns the heap allocation to deallocate. On failure, produces
6649/// a diagnostic and returns None.
6650static Optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E,
6651 const LValue &Pointer,
6652 DynAlloc::Kind DeallocKind) {
6653 auto PointerAsString = [&] {
6654 return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy);
6655 };
6656
6657 DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>();
6658 if (!DA) {
6659 Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc)
6660 << PointerAsString();
6661 if (Pointer.Base)
6662 NoteLValueLocation(Info, Pointer.Base);
6663 return None;
6664 }
6665
6666 Optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
6667 if (!Alloc) {
6668 Info.FFDiag(E, diag::note_constexpr_double_delete);
6669 return None;
6670 }
6671
6672 QualType AllocType = Pointer.Base.getDynamicAllocType();
6673 if (DeallocKind != (*Alloc)->getKind()) {
6674 Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch)
6675 << DeallocKind << (*Alloc)->getKind() << AllocType;
6676 NoteLValueLocation(Info, Pointer.Base);
6677 return None;
6678 }
6679
6680 bool Subobject = false;
6681 if (DeallocKind == DynAlloc::New) {
6682 Subobject = Pointer.Designator.MostDerivedPathLength != 0 ||
6683 Pointer.Designator.isOnePastTheEnd();
6684 } else {
6685 Subobject = Pointer.Designator.Entries.size() != 1 ||
6686 Pointer.Designator.Entries[0].getAsArrayIndex() != 0;
6687 }
6688 if (Subobject) {
6689 Info.FFDiag(E, diag::note_constexpr_delete_subobject)
6690 << PointerAsString() << Pointer.Designator.isOnePastTheEnd();
6691 return None;
6692 }
6693
6694 return Alloc;
6695}
6696
6697// Perform a call to 'operator delete' or '__builtin_operator_delete'.
6698bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) {
6699 if (Info.checkingPotentialConstantExpression() ||
6700 Info.SpeculativeEvaluationDepth)
6701 return false;
6702
6703 // This is permitted only within a call to std::allocator<T>::deallocate.
6704 if (!Info.getStdAllocatorCaller("deallocate")) {
6705 Info.FFDiag(E->getExprLoc());
6706 return true;
6707 }
6708
6709 LValue Pointer;
6710 if (!EvaluatePointer(E->getArg(0), Pointer, Info))
6711 return false;
6712 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I)
6713 EvaluateIgnoredValue(Info, E->getArg(I));
6714
6715 if (Pointer.Designator.Invalid)
6716 return false;
6717
6718 // Deleting a null pointer would have no effect, but it's not permitted by
6719 // std::allocator<T>::deallocate's contract.
6720 if (Pointer.isNullPointer()) {
6721 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_deallocate_null);
6722 return true;
6723 }
6724
6725 if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator))
6726 return false;
6727
6728 Info.HeapAllocs.erase(Pointer.Base.get<DynamicAllocLValue>());
6729 return true;
6730}
6731
6732//===----------------------------------------------------------------------===//
6733// Generic Evaluation
6734//===----------------------------------------------------------------------===//
6735namespace {
6736
6737class BitCastBuffer {
6738 // FIXME: We're going to need bit-level granularity when we support
6739 // bit-fields.
6740 // FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but
6741 // we don't support a host or target where that is the case. Still, we should
6742 // use a more generic type in case we ever do.
6743 SmallVector<Optional<unsigned char>, 32> Bytes;
6744
6745 static_assert(std::numeric_limits<unsigned char>::digits >= 8,
6746 "Need at least 8 bit unsigned char");
6747
6748 bool TargetIsLittleEndian;
6749
6750public:
6751 BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian)
6752 : Bytes(Width.getQuantity()),
6753 TargetIsLittleEndian(TargetIsLittleEndian) {}
6754
6755 LLVM_NODISCARD[[clang::warn_unused_result]]
6756 bool readObject(CharUnits Offset, CharUnits Width,
6757 SmallVectorImpl<unsigned char> &Output) const {
6758 for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
6759 // If a byte of an integer is uninitialized, then the whole integer is
6760 // uninitalized.
6761 if (!Bytes[I.getQuantity()])
6762 return false;
6763 Output.push_back(*Bytes[I.getQuantity()]);
6764 }
6765 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6766 std::reverse(Output.begin(), Output.end());
6767 return true;
6768 }
6769
6770 void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
6771 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6772 std::reverse(Input.begin(), Input.end());
6773
6774 size_t Index = 0;
6775 for (unsigned char Byte : Input) {
6776 assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?")((void)0);
6777 Bytes[Offset.getQuantity() + Index] = Byte;
6778 ++Index;
6779 }
6780 }
6781
6782 size_t size() { return Bytes.size(); }
6783};
6784
6785/// Traverse an APValue to produce an BitCastBuffer, emulating how the current
6786/// target would represent the value at runtime.
6787class APValueToBufferConverter {
6788 EvalInfo &Info;
6789 BitCastBuffer Buffer;
6790 const CastExpr *BCE;
6791
6792 APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth,
6793 const CastExpr *BCE)
6794 : Info(Info),
6795 Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
6796 BCE(BCE) {}
6797
6798 bool visit(const APValue &Val, QualType Ty) {
6799 return visit(Val, Ty, CharUnits::fromQuantity(0));
6800 }
6801
6802 // Write out Val with type Ty into Buffer starting at Offset.
6803 bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
6804 assert((size_t)Offset.getQuantity() <= Buffer.size())((void)0);
6805
6806 // As a special case, nullptr_t has an indeterminate value.
6807 if (Ty->isNullPtrType())
6808 return true;
6809
6810 // Dig through Src to find the byte at SrcOffset.
6811 switch (Val.getKind()) {
6812 case APValue::Indeterminate:
6813 case APValue::None:
6814 return true;
6815
6816 case APValue::Int:
6817 return visitInt(Val.getInt(), Ty, Offset);
6818 case APValue::Float:
6819 return visitFloat(Val.getFloat(), Ty, Offset);
6820 case APValue::Array:
6821 return visitArray(Val, Ty, Offset);
6822 case APValue::Struct:
6823 return visitRecord(Val, Ty, Offset);
6824
6825 case APValue::ComplexInt:
6826 case APValue::ComplexFloat:
6827 case APValue::Vector:
6828 case APValue::FixedPoint:
6829 // FIXME: We should support these.
6830
6831 case APValue::Union:
6832 case APValue::MemberPointer:
6833 case APValue::AddrLabelDiff: {
6834 Info.FFDiag(BCE->getBeginLoc(),
6835 diag::note_constexpr_bit_cast_unsupported_type)
6836 << Ty;
6837 return false;
6838 }
6839
6840 case APValue::LValue:
6841 llvm_unreachable("LValue subobject in bit_cast?")__builtin_unreachable();
6842 }
6843 llvm_unreachable("Unhandled APValue::ValueKind")__builtin_unreachable();
6844 }
6845
6846 bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
6847 const RecordDecl *RD = Ty->getAsRecordDecl();
6848 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6849
6850 // Visit the base classes.
6851 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
6852 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
6853 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
6854 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
6855
6856 if (!visitRecord(Val.getStructBase(I), BS.getType(),
6857 Layout.getBaseClassOffset(BaseDecl) + Offset))
6858 return false;
6859 }
6860 }
6861
6862 // Visit the fields.
6863 unsigned FieldIdx = 0;
6864 for (FieldDecl *FD : RD->fields()) {
6865 if (FD->isBitField()) {
6866 Info.FFDiag(BCE->getBeginLoc(),
6867 diag::note_constexpr_bit_cast_unsupported_bitfield);
6868 return false;
6869 }
6870
6871 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
6872
6873 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 &&((void)0)
6874 "only bit-fields can have sub-char alignment")((void)0);
6875 CharUnits FieldOffset =
6876 Info.Ctx.toCharUnitsFromBits(FieldOffsetBits) + Offset;
6877 QualType FieldTy = FD->getType();
6878 if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset))
6879 return false;
6880 ++FieldIdx;
6881 }
6882
6883 return true;
6884 }
6885
6886 bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
6887 const auto *CAT =
6888 dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe());
6889 if (!CAT)
6890 return false;
6891
6892 CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType());
6893 unsigned NumInitializedElts = Val.getArrayInitializedElts();
6894 unsigned ArraySize = Val.getArraySize();
6895 // First, initialize the initialized elements.
6896 for (unsigned I = 0; I != NumInitializedElts; ++I) {
6897 const APValue &SubObj = Val.getArrayInitializedElt(I);
6898 if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth))
6899 return false;
6900 }
6901
6902 // Next, initialize the rest of the array using the filler.
6903 if (Val.hasArrayFiller()) {
6904 const APValue &Filler = Val.getArrayFiller();
6905 for (unsigned I = NumInitializedElts; I != ArraySize; ++I) {
6906 if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth))
6907 return false;
6908 }
6909 }
6910
6911 return true;
6912 }
6913
6914 bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
6915 APSInt AdjustedVal = Val;
6916 unsigned Width = AdjustedVal.getBitWidth();
6917 if (Ty->isBooleanType()) {
6918 Width = Info.Ctx.getTypeSize(Ty);
6919 AdjustedVal = AdjustedVal.extend(Width);
6920 }
6921
6922 SmallVector<unsigned char, 8> Bytes(Width / 8);
6923 llvm::StoreIntToMemory(AdjustedVal, &*Bytes.begin(), Width / 8);
6924 Buffer.writeObject(Offset, Bytes);
6925 return true;
6926 }
6927
6928 bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
6929 APSInt AsInt(Val.bitcastToAPInt());
6930 return visitInt(AsInt, Ty, Offset);
6931 }
6932
6933public:
6934 static Optional<BitCastBuffer> convert(EvalInfo &Info, const APValue &Src,
6935 const CastExpr *BCE) {
6936 CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType());
6937 APValueToBufferConverter Converter(Info, DstSize, BCE);
6938 if (!Converter.visit(Src, BCE->getSubExpr()->getType()))
6939 return None;
6940 return Converter.Buffer;
6941 }
6942};
6943
6944/// Write an BitCastBuffer into an APValue.
6945class BufferToAPValueConverter {
6946 EvalInfo &Info;
6947 const BitCastBuffer &Buffer;
6948 const CastExpr *BCE;
6949
6950 BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer,
6951 const CastExpr *BCE)
6952 : Info(Info), Buffer(Buffer), BCE(BCE) {}
6953
6954 // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
6955 // with an invalid type, so anything left is a deficiency on our part (FIXME).
6956 // Ideally this will be unreachable.
6957 llvm::NoneType unsupportedType(QualType Ty) {
6958 Info.FFDiag(BCE->getBeginLoc(),
6959 diag::note_constexpr_bit_cast_unsupported_type)
6960 << Ty;
6961 return None;
6962 }
6963
6964 llvm::NoneType unrepresentableValue(QualType Ty, const APSInt &Val) {
6965 Info.FFDiag(BCE->getBeginLoc(),
6966 diag::note_constexpr_bit_cast_unrepresentable_value)
6967 << Ty << toString(Val, /*Radix=*/10);
6968 return None;
6969 }
6970
6971 Optional<APValue> visit(const BuiltinType *T, CharUnits Offset,
6972 const EnumType *EnumSugar = nullptr) {
6973 if (T->isNullPtrType()) {
6974 uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QualType(T, 0));
6975 return APValue((Expr *)nullptr,
6976 /*Offset=*/CharUnits::fromQuantity(NullValue),
6977 APValue::NoLValuePath{}, /*IsNullPtr=*/true);
6978 }
6979
6980 CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);
6981
6982 // Work around floating point types that contain unused padding bytes. This
6983 // is really just `long double` on x86, which is the only fundamental type
6984 // with padding bytes.
6985 if (T->isRealFloatingType()) {
6986 const llvm::fltSemantics &Semantics =
6987 Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
6988 unsigned NumBits = llvm::APFloatBase::getSizeInBits(Semantics);
6989 assert(NumBits % 8 == 0)((void)0);
6990 CharUnits NumBytes = CharUnits::fromQuantity(NumBits / 8);
6991 if (NumBytes != SizeOf)
6992 SizeOf = NumBytes;
6993 }
6994
6995 SmallVector<uint8_t, 8> Bytes;
6996 if (!Buffer.readObject(Offset, SizeOf, Bytes)) {
6997 // If this is std::byte or unsigned char, then its okay to store an
6998 // indeterminate value.
6999 bool IsStdByte = EnumSugar && EnumSugar->isStdByteType();
7000 bool IsUChar =
7001 !EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) ||
7002 T->isSpecificBuiltinType(BuiltinType::Char_U));
7003 if (!IsStdByte && !IsUChar) {
7004 QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0);
7005 Info.FFDiag(BCE->getExprLoc(),
7006 diag::note_constexpr_bit_cast_indet_dest)
7007 << DisplayType << Info.Ctx.getLangOpts().CharIsSigned;
7008 return None;
7009 }
7010
7011 return APValue::IndeterminateValue();
7012 }
7013
7014 APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true);
7015 llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size());
7016
7017 if (T->isIntegralOrEnumerationType()) {
7018 Val.setIsSigned(T->isSignedIntegerOrEnumerationType());
7019
7020 unsigned IntWidth = Info.Ctx.getIntWidth(QualType(T, 0));
7021 if (IntWidth != Val.getBitWidth()) {
7022 APSInt Truncated = Val.trunc(IntWidth);
7023 if (Truncated.extend(Val.getBitWidth()) != Val)
7024 return unrepresentableValue(QualType(T, 0), Val);
7025 Val = Truncated;
7026 }
7027
7028 return APValue(Val);
7029 }
7030
7031 if (T->isRealFloatingType()) {
7032 const llvm::fltSemantics &Semantics =
7033 Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
7034 return APValue(APFloat(Semantics, Val));
7035 }
7036
7037 return unsupportedType(QualType(T, 0));
7038 }
7039
7040 Optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
7041 const RecordDecl *RD = RTy->getAsRecordDecl();
7042 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
7043
7044 unsigned NumBases = 0;
7045 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
7046 NumBases = CXXRD->getNumBases();
7047
7048 APValue ResultVal(APValue::UninitStruct(), NumBases,
7049 std::distance(RD->field_begin(), RD->field_end()));
7050
7051 // Visit the base classes.
7052 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
7053 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
7054 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
7055 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
7056 if (BaseDecl->isEmpty() ||
7057 Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero())
7058 continue;
7059
7060 Optional<APValue> SubObj = visitType(
7061 BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset);
7062 if (!SubObj)
7063 return None;
7064 ResultVal.getStructBase(I) = *SubObj;
7065 }
7066 }
7067
7068 // Visit the fields.
7069 unsigned FieldIdx = 0;
7070 for (FieldDecl *FD : RD->fields()) {
7071 // FIXME: We don't currently support bit-fields. A lot of the logic for
7072 // this is in CodeGen, so we need to factor it around.
7073 if (FD->isBitField()) {
7074 Info.FFDiag(BCE->getBeginLoc(),
7075 diag::note_constexpr_bit_cast_unsupported_bitfield);
7076 return None;
7077 }
7078
7079 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
7080 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0)((void)0);
7081
7082 CharUnits FieldOffset =
7083 CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) +
7084 Offset;
7085 QualType FieldTy = FD->getType();
7086 Optional<APValue> SubObj = visitType(FieldTy, FieldOffset);
7087 if (!SubObj)
7088 return None;
7089 ResultVal.getStructField(FieldIdx) = *SubObj;
7090 ++FieldIdx;
7091 }
7092
7093 return ResultVal;
7094 }
7095
7096 Optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
7097 QualType RepresentationType = Ty->getDecl()->getIntegerType();
7098 assert(!RepresentationType.isNull() &&((void)0)
7099 "enum forward decl should be caught by Sema")((void)0);
7100 const auto *AsBuiltin =
7101 RepresentationType.getCanonicalType()->castAs<BuiltinType>();
7102 // Recurse into the underlying type. Treat std::byte transparently as
7103 // unsigned char.
7104 return visit(AsBuiltin, Offset, /*EnumTy=*/Ty);
7105 }
7106
7107 Optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
7108 size_t Size = Ty->getSize().getLimitedValue();
7109 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType());
7110
7111 APValue ArrayValue(APValue::UninitArray(), Size, Size);
7112 for (size_t I = 0; I != Size; ++I) {
7113 Optional<APValue> ElementValue =
7114 visitType(Ty->getElementType(), Offset + I * ElementWidth);
7115 if (!ElementValue)
7116 return None;
7117 ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
7118 }
7119
7120 return ArrayValue;
7121 }
7122
7123 Optional<APValue> visit(const Type *Ty, CharUnits Offset) {
7124 return unsupportedType(QualType(Ty, 0));
7125 }
7126
7127 Optional<APValue> visitType(QualType Ty, CharUnits Offset) {
7128 QualType Can = Ty.getCanonicalType();
7129
7130 switch (Can->getTypeClass()) {
7131#define TYPE(Class, Base) \
7132 case Type::Class: \
7133 return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
7134#define ABSTRACT_TYPE(Class, Base)
7135#define NON_CANONICAL_TYPE(Class, Base) \
7136 case Type::Class: \
7137 llvm_unreachable("non-canonical type should be impossible!")__builtin_unreachable();
7138#define DEPENDENT_TYPE(Class, Base) \
7139 case Type::Class: \
7140 llvm_unreachable( \__builtin_unreachable()
7141 "dependent types aren't supported in the constant evaluator!")__builtin_unreachable();
7142#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base)case Type::Class: __builtin_unreachable(); \
7143 case Type::Class: \
7144 llvm_unreachable("either dependent or not canonical!")__builtin_unreachable();
7145#include "clang/AST/TypeNodes.inc"
7146 }
7147 llvm_unreachable("Unhandled Type::TypeClass")__builtin_unreachable();
7148 }
7149
7150public:
7151 // Pull out a full value of type DstType.
7152 static Optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer,
7153 const CastExpr *BCE) {
7154 BufferToAPValueConverter Converter(Info, Buffer, BCE);
7155 return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(0));
7156 }
7157};
7158
7159static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
7160 QualType Ty, EvalInfo *Info,
7161 const ASTContext &Ctx,
7162 bool CheckingDest) {
7163 Ty = Ty.getCanonicalType();
7164
7165 auto diag = [&](int Reason) {
7166 if (Info)
7167 Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type)
7168 << CheckingDest << (Reason == 4) << Reason;
7169 return false;
7170 };
7171 auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
7172 if (Info)
7173 Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype)
7174 << NoteTy << Construct << Ty;
7175 return false;
7176 };
7177
7178 if (Ty->isUnionType())
7179 return diag(0);
7180 if (Ty->isPointerType())
7181 return diag(1);
7182 if (Ty->isMemberPointerType())
7183 return diag(2);
7184 if (Ty.isVolatileQualified())
7185 return diag(3);
7186
7187 if (RecordDecl *Record = Ty->getAsRecordDecl()) {
7188 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) {
7189 for (CXXBaseSpecifier &BS : CXXRD->bases())
7190 if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx,
7191 CheckingDest))
7192 return note(1, BS.getType(), BS.getBeginLoc());
7193 }
7194 for (FieldDecl *FD : Record->fields()) {
7195 if (FD->getType()->isReferenceType())
7196 return diag(4);
7197 if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx,
7198 CheckingDest))
7199 return note(0, FD->getType(), FD->getBeginLoc());
7200 }
7201 }
7202
7203 if (Ty->isArrayType() &&
7204 !checkBitCastConstexprEligibilityType(Loc, Ctx.getBaseElementType(Ty),
7205 Info, Ctx, CheckingDest))
7206 return false;
7207
7208 return true;
7209}
7210
7211static bool checkBitCastConstexprEligibility(EvalInfo *Info,
7212 const ASTContext &Ctx,
7213 const CastExpr *BCE) {
7214 bool DestOK = checkBitCastConstexprEligibilityType(
7215 BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true);
7216 bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
7217 BCE->getBeginLoc(),
7218 BCE->getSubExpr()->getType(), Info, Ctx, false);
7219 return SourceOK;
7220}
7221
7222static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
7223 APValue &SourceValue,
7224 const CastExpr *BCE) {
7225 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&((void)0)
7226 "no host or target supports non 8-bit chars")((void)0);
7227 assert(SourceValue.isLValue() &&((void)0)
7228 "LValueToRValueBitcast requires an lvalue operand!")((void)0);
7229
7230 if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE))
7231 return false;
7232
7233 LValue SourceLValue;
7234 APValue SourceRValue;
7235 SourceLValue.setFrom(Info.Ctx, SourceValue);
7236 if (!handleLValueToRValueConversion(
7237 Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue,
7238 SourceRValue, /*WantObjectRepresentation=*/true))
7239 return false;
7240
7241 // Read out SourceValue into a char buffer.
7242 Optional<BitCastBuffer> Buffer =
7243 APValueToBufferConverter::convert(Info, SourceRValue, BCE);
7244 if (!Buffer)
7245 return false;
7246
7247 // Write out the buffer into a new APValue.
7248 Optional<APValue> MaybeDestValue =
7249 BufferToAPValueConverter::convert(Info, *Buffer, BCE);
7250 if (!MaybeDestValue)
7251 return false;
7252
7253 DestValue = std::move(*MaybeDestValue);
7254 return true;
7255}
7256
7257template <class Derived>
7258class ExprEvaluatorBase
7259 : public ConstStmtVisitor<Derived, bool> {
7260private:
7261 Derived &getDerived() { return static_cast<Derived&>(*this); }
7262 bool DerivedSuccess(const APValue &V, const Expr *E) {
7263 return getDerived().Success(V, E);
19
Calling 'ComplexExprEvaluator::Success'
7264 }
7265 bool DerivedZeroInitialization(const Expr *E) {
7266 return getDerived().ZeroInitialization(E);
7267 }
7268
7269 // Check whether a conditional operator with a non-constant condition is a
7270 // potential constant expression. If neither arm is a potential constant
7271 // expression, then the conditional operator is not either.
7272 template<typename ConditionalOperator>
7273 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
7274 assert(Info.checkingPotentialConstantExpression())((void)0);
7275
7276 // Speculatively evaluate both arms.
7277 SmallVector<PartialDiagnosticAt, 8> Diag;
7278 {
7279 SpeculativeEvaluationRAII Speculate(Info, &Diag);
7280 StmtVisitorTy::Visit(E->getFalseExpr());
7281 if (Diag.empty())
7282 return;
7283 }
7284
7285 {
7286 SpeculativeEvaluationRAII Speculate(Info, &Diag);
7287 Diag.clear();
7288 StmtVisitorTy::Visit(E->getTrueExpr());
7289 if (Diag.empty())
7290 return;
7291 }
7292
7293 Error(E, diag::note_constexpr_conditional_never_const);
7294 }
7295
7296
7297 template<typename ConditionalOperator>
7298 bool HandleConditionalOperator(const ConditionalOperator *E) {
7299 bool BoolResult;
7300 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
7301 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
7302 CheckPotentialConstantConditional(E);
7303 return false;
7304 }
7305 if (Info.noteFailure()) {
7306 StmtVisitorTy::Visit(E->getTrueExpr());
7307 StmtVisitorTy::Visit(E->getFalseExpr());
7308 }
7309 return false;
7310 }
7311
7312 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
7313 return StmtVisitorTy::Visit(EvalExpr);
7314 }
7315
7316protected:
7317 EvalInfo &Info;
7318 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
7319 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
7320
7321 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
7322 return Info.CCEDiag(E, D);
7323 }
7324
7325 bool ZeroInitialization(const Expr *E) { return Error(E); }
7326
7327public:
7328 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
7329
7330 EvalInfo &getEvalInfo() { return Info; }
7331
7332 /// Report an evaluation error. This should only be called when an error is
7333 /// first discovered. When propagating an error, just return false.
7334 bool Error(const Expr *E, diag::kind D) {
7335 Info.FFDiag(E, D);
7336 return false;
7337 }
7338 bool Error(const Expr *E) {
7339 return Error(E, diag::note_invalid_subexpr_in_const_expr);
7340 }
7341
7342 bool VisitStmt(const Stmt *) {
7343 llvm_unreachable("Expression evaluator should not be called on stmts")__builtin_unreachable();
7344 }
7345 bool VisitExpr(const Expr *E) {
7346 return Error(E);
7347 }
7348
7349 bool VisitConstantExpr(const ConstantExpr *E) {
7350 if (E->hasAPValueResult())
7351 return DerivedSuccess(E->getAPValueResult(), E);
7352
7353 return StmtVisitorTy::Visit(E->getSubExpr());
7354 }
7355
7356 bool VisitParenExpr(const ParenExpr *E)
7357 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7358 bool VisitUnaryExtension(const UnaryOperator *E)
7359 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7360 bool VisitUnaryPlus(const UnaryOperator *E)
7361 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7362 bool VisitChooseExpr(const ChooseExpr *E)
7363 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
7364 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
7365 { return StmtVisitorTy::Visit(E->getResultExpr()); }
7366 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
7367 { return StmtVisitorTy::Visit(E->getReplacement()); }
7368 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) {
7369 TempVersionRAII RAII(*Info.CurrentCall);
7370 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7371 return StmtVisitorTy::Visit(E->getExpr());
7372 }
7373 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
7374 TempVersionRAII RAII(*Info.CurrentCall);
7375 // The initializer may not have been parsed yet, or might be erroneous.
7376 if (!E->getExpr())
7377 return Error(E);
7378 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7379 return StmtVisitorTy::Visit(E->getExpr());
7380 }
7381
7382 bool VisitExprWithCleanups(const ExprWithCleanups *E) {
7383 FullExpressionRAII Scope(Info);
7384 return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy();
7385 }
7386
7387 // Temporaries are registered when created, so we don't care about
7388 // CXXBindTemporaryExpr.
7389 bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
7390 return StmtVisitorTy::Visit(E->getSubExpr());
7391 }
7392
7393 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
7394 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
7395 return static_cast<Derived*>(this)->VisitCastExpr(E);
7396 }
7397 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
7398 if (!Info.Ctx.getLangOpts().CPlusPlus20)
7399 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
7400 return static_cast<Derived*>(this)->VisitCastExpr(E);
7401 }
7402 bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
7403 return static_cast<Derived*>(this)->VisitCastExpr(E);
7404 }
7405
7406 bool VisitBinaryOperator(const BinaryOperator *E) {
7407 switch (E->getOpcode()) {
7408 default:
7409 return Error(E);
7410
7411 case BO_Comma:
7412 VisitIgnoredValue(E->getLHS());
7413 return StmtVisitorTy::Visit(E->getRHS());
7414
7415 case BO_PtrMemD:
7416 case BO_PtrMemI: {
7417 LValue Obj;
7418 if (!HandleMemberPointerAccess(Info, E, Obj))
7419 return false;
7420 APValue Result;
7421 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
7422 return false;
7423 return DerivedSuccess(Result, E);
7424 }
7425 }
7426 }
7427
7428 bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) {
7429 return StmtVisitorTy::Visit(E->getSemanticForm());
7430 }
7431
7432 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
7433 // Evaluate and cache the common expression. We treat it as a temporary,
7434 // even though it's not quite the same thing.
7435 LValue CommonLV;
7436 if (!Evaluate(Info.CurrentCall->createTemporary(
7437 E->getOpaqueValue(),
7438 getStorageType(Info.Ctx, E->getOpaqueValue()),
7439 ScopeKind::FullExpression, CommonLV),
7440 Info, E->getCommon()))
7441 return false;
7442
7443 return HandleConditionalOperator(E);
7444 }
7445
7446 bool VisitConditionalOperator(const ConditionalOperator *E) {
7447 bool IsBcpCall = false;
7448 // If the condition (ignoring parens) is a __builtin_constant_p call,
7449 // the result is a constant expression if it can be folded without
7450 // side-effects. This is an important GNU extension. See GCC PR38377
7451 // for discussion.
7452 if (const CallExpr *CallCE =
7453 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
7454 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
7455 IsBcpCall = true;
7456
7457 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
7458 // constant expression; we can't check whether it's potentially foldable.
7459 // FIXME: We should instead treat __builtin_constant_p as non-constant if
7460 // it would return 'false' in this mode.
7461 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
7462 return false;
7463
7464 FoldConstant Fold(Info, IsBcpCall);
7465 if (!HandleConditionalOperator(E)) {
7466 Fold.keepDiagnostics();
7467 return false;
7468 }
7469
7470 return true;
7471 }
7472
7473 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
7474 if (APValue *Value = Info.CurrentCall->getCurrentTemporary(E))
7475 return DerivedSuccess(*Value, E);
7476
7477 const Expr *Source = E->getSourceExpr();
7478 if (!Source)
7479 return Error(E);
7480 if (Source == E) { // sanity checking.
7481 assert(0 && "OpaqueValueExpr recursively refers to itself")((void)0);
7482 return Error(E);
7483 }
7484 return StmtVisitorTy::Visit(Source);
7485 }
7486
7487 bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
7488 for (const Expr *SemE : E->semantics()) {
7489 if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
7490 // FIXME: We can't handle the case where an OpaqueValueExpr is also the
7491 // result expression: there could be two different LValues that would
7492 // refer to the same object in that case, and we can't model that.
7493 if (SemE == E->getResultExpr())
7494 return Error(E);
7495
7496 // Unique OVEs get evaluated if and when we encounter them when
7497 // emitting the rest of the semantic form, rather than eagerly.
7498 if (OVE->isUnique())
7499 continue;
7500
7501 LValue LV;
7502 if (!Evaluate(Info.CurrentCall->createTemporary(
7503 OVE, getStorageType(Info.Ctx, OVE),
7504 ScopeKind::FullExpression, LV),
7505 Info, OVE->getSourceExpr()))
7506 return false;
7507 } else if (SemE == E->getResultExpr()) {
7508 if (!StmtVisitorTy::Visit(SemE))
7509 return false;
7510 } else {
7511 if (!EvaluateIgnoredValue(Info, SemE))
7512 return false;
7513 }
7514 }
7515 return true;
7516 }
7517
7518 bool VisitCallExpr(const CallExpr *E) {
7519 APValue Result;
7520 if (!handleCallExpr(E, Result, nullptr))
4
Calling 'ExprEvaluatorBase::handleCallExpr'
15
Returning from 'ExprEvaluatorBase::handleCallExpr'
16
Assuming the condition is false
17
Taking false branch
7521 return false;
7522 return DerivedSuccess(Result, E);
18
Calling 'ExprEvaluatorBase::DerivedSuccess'
7523 }
7524
7525 bool handleCallExpr(const CallExpr *E, APValue &Result,
7526 const LValue *ResultSlot) {
7527 CallScopeRAII CallScope(Info);
7528
7529 const Expr *Callee = E->getCallee()->IgnoreParens();
7530 QualType CalleeType = Callee->getType();
7531
7532 const FunctionDecl *FD = nullptr;
7533 LValue *This = nullptr, ThisVal;
7534 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
7535 bool HasQualifier = false;
7536
7537 CallRef Call;
7538
7539 // Extract function decl and 'this' pointer from the callee.
7540 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
5
Taking true branch
7541 const CXXMethodDecl *Member = nullptr;
7542 if (const MemberExpr *ME
6.1
'ME' is null
6.1
'ME' is null
= dyn_cast<MemberExpr>(Callee)) {
6
Assuming 'Callee' is not a 'MemberExpr'
7
Taking false branch
7543 // Explicit bound member calls, such as x.f() or p->g();
7544 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
7545 return false;
7546 Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
7547 if (!Member)
7548 return Error(Callee);
7549 This = &ThisVal;
7550 HasQualifier = ME->hasQualifier();
7551 } else if (const BinaryOperator *BE
8.1
'BE' is null
8.1
'BE' is null
= dyn_cast<BinaryOperator>(Callee)) {
8
Assuming 'Callee' is not a 'BinaryOperator'
9
Taking false branch
7552 // Indirect bound member calls ('.*' or '->*').
7553 const ValueDecl *D =
7554 HandleMemberPointerAccess(Info, BE, ThisVal, false);
7555 if (!D)
7556 return false;
7557 Member = dyn_cast<CXXMethodDecl>(D);
7558 if (!Member)
7559 return Error(Callee);
7560 This = &ThisVal;
7561 } else if (const auto *PDE
10.1
'PDE' is non-null
10.1
'PDE' is non-null
= dyn_cast<CXXPseudoDestructorExpr>(Callee)) {
10
Assuming 'Callee' is a 'CXXPseudoDestructorExpr'
11
Taking true branch
7562 if (!Info.getLangOpts().CPlusPlus20)
12
Assuming field 'CPlusPlus20' is not equal to 0
13
Taking false branch
7563 Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor);
7564 return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) &&
14
Assuming the condition is true
7565 HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType());
7566 } else
7567 return Error(Callee);
7568 FD = Member;
7569 } else if (CalleeType->isFunctionPointerType()) {
7570 LValue CalleeLV;
7571 if (!EvaluatePointer(Callee, CalleeLV, Info))
7572 return false;
7573
7574 if (!CalleeLV.getLValueOffset().isZero())
7575 return Error(Callee);
7576 FD = dyn_cast_or_null<FunctionDecl>(
7577 CalleeLV.getLValueBase().dyn_cast<const ValueDecl *>());
7578 if (!FD)
7579 return Error(Callee);
7580 // Don't call function pointers which have been cast to some other type.
7581 // Per DR (no number yet), the caller and callee can differ in noexcept.
7582 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
7583 CalleeType->getPointeeType(), FD->getType())) {
7584 return Error(E);
7585 }
7586
7587 // For an (overloaded) assignment expression, evaluate the RHS before the
7588 // LHS.
7589 auto *OCE = dyn_cast<CXXOperatorCallExpr>(E);
7590 if (OCE && OCE->isAssignmentOp()) {
7591 assert(Args.size() == 2 && "wrong number of arguments in assignment")((void)0);
7592 Call = Info.CurrentCall->createCall(FD);
7593 if (!EvaluateArgs(isa<CXXMethodDecl>(FD) ? Args.slice(1) : Args, Call,
7594 Info, FD, /*RightToLeft=*/true))
7595 return false;
7596 }
7597
7598 // Overloaded operator calls to member functions are represented as normal
7599 // calls with '*this' as the first argument.
7600 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
7601 if (MD && !MD->isStatic()) {
7602 // FIXME: When selecting an implicit conversion for an overloaded
7603 // operator delete, we sometimes try to evaluate calls to conversion
7604 // operators without a 'this' parameter!
7605 if (Args.empty())
7606 return Error(E);
7607
7608 if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
7609 return false;
7610 This = &ThisVal;
7611 Args = Args.slice(1);
7612 } else if (MD && MD->isLambdaStaticInvoker()) {
7613 // Map the static invoker for the lambda back to the call operator.
7614 // Conveniently, we don't have to slice out the 'this' argument (as is
7615 // being done for the non-static case), since a static member function
7616 // doesn't have an implicit argument passed in.
7617 const CXXRecordDecl *ClosureClass = MD->getParent();
7618 assert(((void)0)
7619 ClosureClass->captures_begin() == ClosureClass->captures_end() &&((void)0)
7620 "Number of captures must be zero for conversion to function-ptr")((void)0);
7621
7622 const CXXMethodDecl *LambdaCallOp =
7623 ClosureClass->getLambdaCallOperator();
7624
7625 // Set 'FD', the function that will be called below, to the call
7626 // operator. If the closure object represents a generic lambda, find
7627 // the corresponding specialization of the call operator.
7628
7629 if (ClosureClass->isGenericLambda()) {
7630 assert(MD->isFunctionTemplateSpecialization() &&((void)0)
7631 "A generic lambda's static-invoker function must be a "((void)0)
7632 "template specialization")((void)0);
7633 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
7634 FunctionTemplateDecl *CallOpTemplate =
7635 LambdaCallOp->getDescribedFunctionTemplate();
7636 void *InsertPos = nullptr;
7637 FunctionDecl *CorrespondingCallOpSpecialization =
7638 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
7639 assert(CorrespondingCallOpSpecialization &&((void)0)
7640 "We must always have a function call operator specialization "((void)0)
7641 "that corresponds to our static invoker specialization")((void)0);
7642 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
7643 } else
7644 FD = LambdaCallOp;
7645 } else if (FD->isReplaceableGlobalAllocationFunction()) {
7646 if (FD->getDeclName().getCXXOverloadedOperator() == OO_New ||
7647 FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) {
7648 LValue Ptr;
7649 if (!HandleOperatorNewCall(Info, E, Ptr))
7650 return false;
7651 Ptr.moveInto(Result);
7652 return CallScope.destroy();
7653 } else {
7654 return HandleOperatorDeleteCall(Info, E) && CallScope.destroy();
7655 }
7656 }
7657 } else
7658 return Error(E);
7659
7660 // Evaluate the arguments now if we've not already done so.
7661 if (!Call) {
7662 Call = Info.CurrentCall->createCall(FD);
7663 if (!EvaluateArgs(Args, Call, Info, FD))
7664 return false;
7665 }
7666
7667 SmallVector<QualType, 4> CovariantAdjustmentPath;
7668 if (This) {
7669 auto *NamedMember = dyn_cast<CXXMethodDecl>(FD);
7670 if (NamedMember && NamedMember->isVirtual() && !HasQualifier) {
7671 // Perform virtual dispatch, if necessary.
7672 FD = HandleVirtualDispatch(Info, E, *This, NamedMember,
7673 CovariantAdjustmentPath);
7674 if (!FD)
7675 return false;
7676 } else {
7677 // Check that the 'this' pointer points to an object of the right type.
7678 // FIXME: If this is an assignment operator call, we may need to change
7679 // the active union member before we check this.
7680 if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember))
7681 return false;
7682 }
7683 }
7684
7685 // Destructor calls are different enough that they have their own codepath.
7686 if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) {
7687 assert(This && "no 'this' pointer for destructor call")((void)0);
7688 return HandleDestruction(Info, E, *This,
7689 Info.Ctx.getRecordType(DD->getParent())) &&
7690 CallScope.destroy();
7691 }
7692
7693 const FunctionDecl *Definition = nullptr;
7694 Stmt *Body = FD->getBody(Definition);
7695
7696 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
7697 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Call,
7698 Body, Info, Result, ResultSlot))
7699 return false;
7700
7701 if (!CovariantAdjustmentPath.empty() &&
7702 !HandleCovariantReturnAdjustment(Info, E, Result,
7703 CovariantAdjustmentPath))
7704 return false;
7705
7706 return CallScope.destroy();
7707 }
7708
7709 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
7710 return StmtVisitorTy::Visit(E->getInitializer());
7711 }
7712 bool VisitInitListExpr(const InitListExpr *E) {
7713 if (E->getNumInits() == 0)
7714 return DerivedZeroInitialization(E);
7715 if (E->getNumInits() == 1)
7716 return StmtVisitorTy::Visit(E->getInit(0));
7717 return Error(E);
7718 }
7719 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
7720 return DerivedZeroInitialization(E);
7721 }
7722 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
7723 return DerivedZeroInitialization(E);
7724 }
7725 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
7726 return DerivedZeroInitialization(E);
7727 }
7728
7729 /// A member expression where the object is a prvalue is itself a prvalue.
7730 bool VisitMemberExpr(const MemberExpr *E) {
7731 assert(!Info.Ctx.getLangOpts().CPlusPlus11 &&((void)0)
7732 "missing temporary materialization conversion")((void)0);
7733 assert(!E->isArrow() && "missing call to bound member function?")((void)0);
7734
7735 APValue Val;
7736 if (!Evaluate(Val, Info, E->getBase()))
7737 return false;
7738
7739 QualType BaseTy = E->getBase()->getType();
7740
7741 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
7742 if (!FD) return Error(E);
7743 assert(!FD->getType()->isReferenceType() && "prvalue reference?")((void)0);
7744 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==((void)0)
7745 FD->getParent()->getCanonicalDecl() && "record / field mismatch")((void)0);
7746
7747 // Note: there is no lvalue base here. But this case should only ever
7748 // happen in C or in C++98, where we cannot be evaluating a constexpr
7749 // constructor, which is the only case the base matters.
7750 CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy);
7751 SubobjectDesignator Designator(BaseTy);
7752 Designator.addDeclUnchecked(FD);
7753
7754 APValue Result;
7755 return extractSubobject(Info, E, Obj, Designator, Result) &&
7756 DerivedSuccess(Result, E);
7757 }
7758
7759 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) {
7760 APValue Val;
7761 if (!Evaluate(Val, Info, E->getBase()))
7762 return false;
7763
7764 if (Val.isVector()) {
7765 SmallVector<uint32_t, 4> Indices;
7766 E->getEncodedElementAccess(Indices);
7767 if (Indices.size() == 1) {
7768 // Return scalar.
7769 return DerivedSuccess(Val.getVectorElt(Indices[0]), E);
7770 } else {
7771 // Construct new APValue vector.
7772 SmallVector<APValue, 4> Elts;
7773 for (unsigned I = 0; I < Indices.size(); ++I) {
7774 Elts.push_back(Val.getVectorElt(Indices[I]));
7775 }
7776 APValue VecResult(Elts.data(), Indices.size());
7777 return DerivedSuccess(VecResult, E);
7778 }
7779 }
7780
7781 return false;
7782 }
7783
7784 bool VisitCastExpr(const CastExpr *E) {
7785 switch (E->getCastKind()) {
7786 default:
7787 break;
7788
7789 case CK_AtomicToNonAtomic: {
7790 APValue AtomicVal;
7791 // This does not need to be done in place even for class/array types:
7792 // atomic-to-non-atomic conversion implies copying the object
7793 // representation.
7794 if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
7795 return false;
7796 return DerivedSuccess(AtomicVal, E);
7797 }
7798
7799 case CK_NoOp:
7800 case CK_UserDefinedConversion:
7801 return StmtVisitorTy::Visit(E->getSubExpr());
7802
7803 case CK_LValueToRValue: {
7804 LValue LVal;
7805 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
7806 return false;
7807 APValue RVal;
7808 // Note, we use the subexpression's type in order to retain cv-qualifiers.
7809 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
7810 LVal, RVal))
7811 return false;
7812 return DerivedSuccess(RVal, E);
7813 }
7814 case CK_LValueToRValueBitCast: {
7815 APValue DestValue, SourceValue;
7816 if (!Evaluate(SourceValue, Info, E->getSubExpr()))
7817 return false;
7818 if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, E))
7819 return false;
7820 return DerivedSuccess(DestValue, E);
7821 }
7822
7823 case CK_AddressSpaceConversion: {
7824 APValue Value;
7825 if (!Evaluate(Value, Info, E->getSubExpr()))
7826 return false;
7827 return DerivedSuccess(Value, E);
7828 }
7829 }
7830
7831 return Error(E);
7832 }
7833
7834 bool VisitUnaryPostInc(const UnaryOperator *UO) {
7835 return VisitUnaryPostIncDec(UO);
7836 }
7837 bool VisitUnaryPostDec(const UnaryOperator *UO) {
7838 return VisitUnaryPostIncDec(UO);
7839 }
7840 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
7841 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
7842 return Error(UO);
7843
7844 LValue LVal;
7845 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
7846 return false;
7847 APValue RVal;
7848 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
7849 UO->isIncrementOp(), &RVal))
7850 return false;
7851 return DerivedSuccess(RVal, UO);
7852 }
7853
7854 bool VisitStmtExpr(const StmtExpr *E) {
7855 // We will have checked the full-expressions inside the statement expression
7856 // when they were completed, and don't need to check them again now.
7857 llvm::SaveAndRestore<bool> NotCheckingForUB(
7858 Info.CheckingForUndefinedBehavior, false);
7859
7860 const CompoundStmt *CS = E->getSubStmt();
7861 if (CS->body_empty())
7862 return true;
7863
7864 BlockScopeRAII Scope(Info);
7865 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
7866 BE = CS->body_end();
7867 /**/; ++BI) {
7868 if (BI + 1 == BE) {
7869 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
7870 if (!FinalExpr) {
7871 Info.FFDiag((*BI)->getBeginLoc(),
7872 diag::note_constexpr_stmt_expr_unsupported);
7873 return false;
7874 }
7875 return this->Visit(FinalExpr) && Scope.destroy();
7876 }
7877
7878 APValue ReturnValue;
7879 StmtResult Result = { ReturnValue, nullptr };
7880 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
7881 if (ESR != ESR_Succeeded) {
7882 // FIXME: If the statement-expression terminated due to 'return',
7883 // 'break', or 'continue', it would be nice to propagate that to
7884 // the outer statement evaluation rather than bailing out.
7885 if (ESR != ESR_Failed)
7886 Info.FFDiag((*BI)->getBeginLoc(),
7887 diag::note_constexpr_stmt_expr_unsupported);
7888 return false;
7889 }
7890 }
7891
7892 llvm_unreachable("Return from function from the loop above.")__builtin_unreachable();
7893 }
7894
7895 /// Visit a value which is evaluated, but whose value is ignored.
7896 void VisitIgnoredValue(const Expr *E) {
7897 EvaluateIgnoredValue(Info, E);
7898 }
7899
7900 /// Potentially visit a MemberExpr's base expression.
7901 void VisitIgnoredBaseExpression(const Expr *E) {
7902 // While MSVC doesn't evaluate the base expression, it does diagnose the
7903 // presence of side-effecting behavior.
7904 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
7905 return;
7906 VisitIgnoredValue(E);
7907 }
7908};
7909
7910} // namespace
7911
7912//===----------------------------------------------------------------------===//
7913// Common base class for lvalue and temporary evaluation.
7914//===----------------------------------------------------------------------===//
7915namespace {
7916template<class Derived>
7917class LValueExprEvaluatorBase
7918 : public ExprEvaluatorBase<Derived> {
7919protected:
7920 LValue &Result;
7921 bool InvalidBaseOK;
7922 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
7923 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
7924
7925 bool Success(APValue::LValueBase B) {
7926 Result.set(B);
7927 return true;
7928 }
7929
7930 bool evaluatePointer(const Expr *E, LValue &Result) {
7931 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
7932 }
7933
7934public:
7935 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
7936 : ExprEvaluatorBaseTy(Info), Result(Result),
7937 InvalidBaseOK(InvalidBaseOK) {}
7938
7939 bool Success(const APValue &V, const Expr *E) {
7940 Result.setFrom(this->Info.Ctx, V);
7941 return true;
7942 }
7943
7944 bool VisitMemberExpr(const MemberExpr *E) {
7945 // Handle non-static data members.
7946 QualType BaseTy;
7947 bool EvalOK;
7948 if (E->isArrow()) {
7949 EvalOK = evaluatePointer(E->getBase(), Result);
7950 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
7951 } else if (E->getBase()->isPRValue()) {
7952 assert(E->getBase()->getType()->isRecordType())((void)0);
7953 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
7954 BaseTy = E->getBase()->getType();
7955 } else {
7956 EvalOK = this->Visit(E->getBase());
7957 BaseTy = E->getBase()->getType();
7958 }
7959 if (!EvalOK) {
7960 if (!InvalidBaseOK)
7961 return false;
7962 Result.setInvalid(E);
7963 return true;
7964 }
7965
7966 const ValueDecl *MD = E->getMemberDecl();
7967 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
7968 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==((void)0)
7969 FD->getParent()->getCanonicalDecl() && "record / field mismatch")((void)0);
7970 (void)BaseTy;
7971 if (!HandleLValueMember(this->Info, E, Result, FD))
7972 return false;
7973 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
7974 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
7975 return false;
7976 } else
7977 return this->Error(E);
7978
7979 if (MD->getType()->isReferenceType()) {
7980 APValue RefValue;
7981 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
7982 RefValue))
7983 return false;
7984 return Success(RefValue, E);
7985 }
7986 return true;
7987 }
7988
7989 bool VisitBinaryOperator(const BinaryOperator *E) {
7990 switch (E->getOpcode()) {
7991 default:
7992 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
7993
7994 case BO_PtrMemD:
7995 case BO_PtrMemI:
7996 return HandleMemberPointerAccess(this->Info, E, Result);
7997 }
7998 }
7999
8000 bool VisitCastExpr(const CastExpr *E) {
8001 switch (E->getCastKind()) {
8002 default:
8003 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8004
8005 case CK_DerivedToBase:
8006 case CK_UncheckedDerivedToBase:
8007 if (!this->Visit(E->getSubExpr()))
8008 return false;
8009
8010 // Now figure out the necessary offset to add to the base LV to get from
8011 // the derived class to the base class.
8012 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
8013 Result);
8014 }
8015 }
8016};
8017}
8018
8019//===----------------------------------------------------------------------===//
8020// LValue Evaluation
8021//
8022// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
8023// function designators (in C), decl references to void objects (in C), and
8024// temporaries (if building with -Wno-address-of-temporary).
8025//
8026// LValue evaluation produces values comprising a base expression of one of the
8027// following types:
8028// - Declarations
8029// * VarDecl
8030// * FunctionDecl
8031// - Literals
8032// * CompoundLiteralExpr in C (and in global scope in C++)
8033// * StringLiteral
8034// * PredefinedExpr
8035// * ObjCStringLiteralExpr
8036// * ObjCEncodeExpr
8037// * AddrLabelExpr
8038// * BlockExpr
8039// * CallExpr for a MakeStringConstant builtin
8040// - typeid(T) expressions, as TypeInfoLValues
8041// - Locals and temporaries
8042// * MaterializeTemporaryExpr
8043// * Any Expr, with a CallIndex indicating the function in which the temporary
8044// was evaluated, for cases where the MaterializeTemporaryExpr is missing
8045// from the AST (FIXME).
8046// * A MaterializeTemporaryExpr that has static storage duration, with no
8047// CallIndex, for a lifetime-extended temporary.
8048// * The ConstantExpr that is currently being evaluated during evaluation of an
8049// immediate invocation.
8050// plus an offset in bytes.
8051//===----------------------------------------------------------------------===//
8052namespace {
8053class LValueExprEvaluator
8054 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
8055public:
8056 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
8057 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
8058
8059 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
8060 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
8061
8062 bool VisitDeclRefExpr(const DeclRefExpr *E);
8063 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
8064 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
8065 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
8066 bool VisitMemberExpr(const MemberExpr *E);
8067 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
8068 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
8069 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
8070 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
8071 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
8072 bool VisitUnaryDeref(const UnaryOperator *E);
8073 bool VisitUnaryReal(const UnaryOperator *E);
8074 bool VisitUnaryImag(const UnaryOperator *E);
8075 bool VisitUnaryPreInc(const UnaryOperator *UO) {
8076 return VisitUnaryPreIncDec(UO);
8077 }
8078 bool VisitUnaryPreDec(const UnaryOperator *UO) {
8079 return VisitUnaryPreIncDec(UO);
8080 }
8081 bool VisitBinAssign(const BinaryOperator *BO);
8082 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
8083
8084 bool VisitCastExpr(const CastExpr *E) {
8085 switch (E->getCastKind()) {
8086 default:
8087 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
8088
8089 case CK_LValueBitCast:
8090 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8091 if (!Visit(E->getSubExpr()))
8092 return false;
8093 Result.Designator.setInvalid();
8094 return true;
8095
8096 case CK_BaseToDerived:
8097 if (!Visit(E->getSubExpr()))
8098 return false;
8099 return HandleBaseToDerivedCast(Info, E, Result);
8100
8101 case CK_Dynamic:
8102 if (!Visit(E->getSubExpr()))
8103 return false;
8104 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
8105 }
8106 }
8107};
8108} // end anonymous namespace
8109
8110/// Evaluate an expression as an lvalue. This can be legitimately called on
8111/// expressions which are not glvalues, in three cases:
8112/// * function designators in C, and
8113/// * "extern void" objects
8114/// * @selector() expressions in Objective-C
8115static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
8116 bool InvalidBaseOK) {
8117 assert(!E->isValueDependent())((void)0);
8118 assert(E->isGLValue() || E->getType()->isFunctionType() ||((void)0)
8119 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E))((void)0);
8120 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8121}
8122
8123bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
8124 const NamedDecl *D = E->getDecl();
8125 if (isa<FunctionDecl, MSGuidDecl, TemplateParamObjectDecl>(D))
8126 return Success(cast<ValueDecl>(D));
8127 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
8128 return VisitVarDecl(E, VD);
8129 if (const BindingDecl *BD = dyn_cast<BindingDecl>(D))
8130 return Visit(BD->getBinding());
8131 return Error(E);
8132}
8133
8134
8135bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
8136
8137 // If we are within a lambda's call operator, check whether the 'VD' referred
8138 // to within 'E' actually represents a lambda-capture that maps to a
8139 // data-member/field within the closure object, and if so, evaluate to the
8140 // field or what the field refers to.
8141 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) &&
8142 isa<DeclRefExpr>(E) &&
8143 cast<DeclRefExpr>(E)->refersToEnclosingVariableOrCapture()) {
8144 // We don't always have a complete capture-map when checking or inferring if
8145 // the function call operator meets the requirements of a constexpr function
8146 // - but we don't need to evaluate the captures to determine constexprness
8147 // (dcl.constexpr C++17).
8148 if (Info.checkingPotentialConstantExpression())
8149 return false;
8150
8151 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
8152 // Start with 'Result' referring to the complete closure object...
8153 Result = *Info.CurrentCall->This;
8154 // ... then update it to refer to the field of the closure object
8155 // that represents the capture.
8156 if (!HandleLValueMember(Info, E, Result, FD))
8157 return false;
8158 // And if the field is of reference type, update 'Result' to refer to what
8159 // the field refers to.
8160 if (FD->getType()->isReferenceType()) {
8161 APValue RVal;
8162 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result,
8163 RVal))
8164 return false;
8165 Result.setFrom(Info.Ctx, RVal);
8166 }
8167 return true;
8168 }
8169 }
8170
8171 CallStackFrame *Frame = nullptr;
8172 unsigned Version = 0;
8173 if (VD->hasLocalStorage()) {
8174 // Only if a local variable was declared in the function currently being
8175 // evaluated, do we expect to be able to find its value in the current
8176 // frame. (Otherwise it was likely declared in an enclosing context and
8177 // could either have a valid evaluatable value (for e.g. a constexpr
8178 // variable) or be ill-formed (and trigger an appropriate evaluation
8179 // diagnostic)).
8180 CallStackFrame *CurrFrame = Info.CurrentCall;
8181 if (CurrFrame->Callee && CurrFrame->Callee->Equals(VD->getDeclContext())) {
8182 // Function parameters are stored in some caller's frame. (Usually the
8183 // immediate caller, but for an inherited constructor they may be more
8184 // distant.)
8185 if (auto *PVD = dyn_cast<ParmVarDecl>(VD)) {
8186 if (CurrFrame->Arguments) {
8187 VD = CurrFrame->Arguments.getOrigParam(PVD);
8188 Frame =
8189 Info.getCallFrameAndDepth(CurrFrame->Arguments.CallIndex).first;
8190 Version = CurrFrame->Arguments.Version;
8191 }
8192 } else {
8193 Frame = CurrFrame;
8194 Version = CurrFrame->getCurrentTemporaryVersion(VD);
8195 }
8196 }
8197 }
8198
8199 if (!VD->getType()->isReferenceType()) {
8200 if (Frame) {
8201 Result.set({VD, Frame->Index, Version});
8202 return true;
8203 }
8204 return Success(VD);
8205 }
8206
8207 if (!Info.getLangOpts().CPlusPlus11) {
8208 Info.CCEDiag(E, diag::note_constexpr_ltor_non_integral, 1)
8209 << VD << VD->getType();
8210 Info.Note(VD->getLocation(), diag::note_declared_at);
8211 }
8212
8213 APValue *V;
8214 if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, V))
8215 return false;
8216 if (!V->hasValue()) {
8217 // FIXME: Is it possible for V to be indeterminate here? If so, we should
8218 // adjust the diagnostic to say that.
8219 if (!Info.checkingPotentialConstantExpression())
8220 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
8221 return false;
8222 }
8223 return Success(*V, E);
8224}
8225
8226bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
8227 const MaterializeTemporaryExpr *E) {
8228 // Walk through the expression to find the materialized temporary itself.
8229 SmallVector<const Expr *, 2> CommaLHSs;
8230 SmallVector<SubobjectAdjustment, 2> Adjustments;
8231 const Expr *Inner =
8232 E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
8233
8234 // If we passed any comma operators, evaluate their LHSs.
8235 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
8236 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
8237 return false;
8238
8239 // A materialized temporary with static storage duration can appear within the
8240 // result of a constant expression evaluation, so we need to preserve its
8241 // value for use outside this evaluation.
8242 APValue *Value;
8243 if (E->getStorageDuration() == SD_Static) {
8244 // FIXME: What about SD_Thread?
8245 Value = E->getOrCreateValue(true);
8246 *Value = APValue();
8247 Result.set(E);
8248 } else {
8249 Value = &Info.CurrentCall->createTemporary(
8250 E, E->getType(),
8251 E->getStorageDuration() == SD_FullExpression ? ScopeKind::FullExpression
8252 : ScopeKind::Block,
8253 Result);
8254 }
8255
8256 QualType Type = Inner->getType();
8257
8258 // Materialize the temporary itself.
8259 if (!EvaluateInPlace(*Value, Info, Result, Inner)) {
8260 *Value = APValue();
8261 return false;
8262 }
8263
8264 // Adjust our lvalue to refer to the desired subobject.
8265 for (unsigned I = Adjustments.size(); I != 0; /**/) {
8266 --I;
8267 switch (Adjustments[I].Kind) {
8268 case SubobjectAdjustment::DerivedToBaseAdjustment:
8269 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
8270 Type, Result))
8271 return false;
8272 Type = Adjustments[I].DerivedToBase.BasePath->getType();
8273 break;
8274
8275 case SubobjectAdjustment::FieldAdjustment:
8276 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
8277 return false;
8278 Type = Adjustments[I].Field->getType();
8279 break;
8280
8281 case SubobjectAdjustment::MemberPointerAdjustment:
8282 if (!HandleMemberPointerAccess(this->Info, Type, Result,
8283 Adjustments[I].Ptr.RHS))
8284 return false;
8285 Type = Adjustments[I].Ptr.MPT->getPointeeType();
8286 break;
8287 }
8288 }
8289
8290 return true;
8291}
8292
8293bool
8294LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
8295 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&((void)0)
8296 "lvalue compound literal in c++?")((void)0);
8297 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
8298 // only see this when folding in C, so there's no standard to follow here.
8299 return Success(E);
8300}
8301
8302bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
8303 TypeInfoLValue TypeInfo;
8304
8305 if (!E->isPotentiallyEvaluated()) {
8306 if (E->isTypeOperand())
8307 TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr());
8308 else
8309 TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
8310 } else {
8311 if (!Info.Ctx.getLangOpts().CPlusPlus20) {
8312 Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic)
8313 << E->getExprOperand()->getType()
8314 << E->getExprOperand()->getSourceRange();
8315 }
8316
8317 if (!Visit(E->getExprOperand()))
8318 return false;
8319
8320 Optional<DynamicType> DynType =
8321 ComputeDynamicType(Info, E, Result, AK_TypeId);
8322 if (!DynType)
8323 return false;
8324
8325 TypeInfo =
8326 TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr());
8327 }
8328
8329 return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType()));
8330}
8331
8332bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
8333 return Success(E->getGuidDecl());
8334}
8335
8336bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
8337 // Handle static data members.
8338 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
8339 VisitIgnoredBaseExpression(E->getBase());
8340 return VisitVarDecl(E, VD);
8341 }
8342
8343 // Handle static member functions.
8344 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
8345 if (MD->isStatic()) {
8346 VisitIgnoredBaseExpression(E->getBase());
8347 return Success(MD);
8348 }
8349 }
8350
8351 // Handle non-static data members.
8352 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
8353}
8354
8355bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
8356 // FIXME: Deal with vectors as array subscript bases.
8357 if (E->getBase()->getType()->isVectorType())
8358 return Error(E);
8359
8360 APSInt Index;
8361 bool Success = true;
8362
8363 // C++17's rules require us to evaluate the LHS first, regardless of which
8364 // side is the base.
8365 for (const Expr *SubExpr : {E->getLHS(), E->getRHS()}) {
8366 if (SubExpr == E->getBase() ? !evaluatePointer(SubExpr, Result)
8367 : !EvaluateInteger(SubExpr, Index, Info)) {
8368 if (!Info.noteFailure())
8369 return false;
8370 Success = false;
8371 }
8372 }
8373
8374 return Success &&
8375 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
8376}
8377
8378bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
8379 return evaluatePointer(E->getSubExpr(), Result);
8380}
8381
8382bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8383 if (!Visit(E->getSubExpr()))
8384 return false;
8385 // __real is a no-op on scalar lvalues.
8386 if (E->getSubExpr()->getType()->isAnyComplexType())
8387 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
8388 return true;
8389}
8390
8391bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8392 assert(E->getSubExpr()->getType()->isAnyComplexType() &&((void)0)
8393 "lvalue __imag__ on scalar?")((void)0);
8394 if (!Visit(E->getSubExpr()))
8395 return false;
8396 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
8397 return true;
8398}
8399
8400bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
8401 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8402 return Error(UO);
8403
8404 if (!this->Visit(UO->getSubExpr()))
8405 return false;
8406
8407 return handleIncDec(
8408 this->Info, UO, Result, UO->getSubExpr()->getType(),
8409 UO->isIncrementOp(), nullptr);
8410}
8411
8412bool LValueExprEvaluator::VisitCompoundAssignOperator(
8413 const CompoundAssignOperator *CAO) {
8414 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8415 return Error(CAO);
8416
8417 bool Success = true;
8418
8419 // C++17 onwards require that we evaluate the RHS first.
8420 APValue RHS;
8421 if (!Evaluate(RHS, this->Info, CAO->getRHS())) {
8422 if (!Info.noteFailure())
8423 return false;
8424 Success = false;
8425 }
8426
8427 // The overall lvalue result is the result of evaluating the LHS.
8428 if (!this->Visit(CAO->getLHS()) || !Success)
8429 return false;
8430
8431 return handleCompoundAssignment(
8432 this->Info, CAO,
8433 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
8434 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
8435}
8436
8437bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
8438 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8439 return Error(E);
8440
8441 bool Success = true;
8442
8443 // C++17 onwards require that we evaluate the RHS first.
8444 APValue NewVal;
8445 if (!Evaluate(NewVal, this->Info, E->getRHS())) {
8446 if (!Info.noteFailure())
8447 return false;
8448 Success = false;
8449 }
8450
8451 if (!this->Visit(E->getLHS()) || !Success)
8452 return false;
8453
8454 if (Info.getLangOpts().CPlusPlus20 &&
8455 !HandleUnionActiveMemberChange(Info, E->getLHS(), Result))
8456 return false;
8457
8458 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
8459 NewVal);
8460}
8461
8462//===----------------------------------------------------------------------===//
8463// Pointer Evaluation
8464//===----------------------------------------------------------------------===//
8465
8466/// Attempts to compute the number of bytes available at the pointer
8467/// returned by a function with the alloc_size attribute. Returns true if we
8468/// were successful. Places an unsigned number into `Result`.
8469///
8470/// This expects the given CallExpr to be a call to a function with an
8471/// alloc_size attribute.
8472static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8473 const CallExpr *Call,
8474 llvm::APInt &Result) {
8475 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
8476
8477 assert(AllocSize && AllocSize->getElemSizeParam().isValid())((void)0);
8478 unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
8479 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
8480 if (Call->getNumArgs() <= SizeArgNo)
8481 return false;
8482
8483 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
8484 Expr::EvalResult ExprResult;
8485 if (!E->EvaluateAsInt(ExprResult, Ctx, Expr::SE_AllowSideEffects))
8486 return false;
8487 Into = ExprResult.Val.getInt();
8488 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
8489 return false;
8490 Into = Into.zextOrSelf(BitsInSizeT);
8491 return true;
8492 };
8493
8494 APSInt SizeOfElem;
8495 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
8496 return false;
8497
8498 if (!AllocSize->getNumElemsParam().isValid()) {
8499 Result = std::move(SizeOfElem);
8500 return true;
8501 }
8502
8503 APSInt NumberOfElems;
8504 unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
8505 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
8506 return false;
8507
8508 bool Overflow;
8509 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
8510 if (Overflow)
8511 return false;
8512
8513 Result = std::move(BytesAvailable);
8514 return true;
8515}
8516
8517/// Convenience function. LVal's base must be a call to an alloc_size
8518/// function.
8519static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8520 const LValue &LVal,
8521 llvm::APInt &Result) {
8522 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&((void)0)
8523 "Can't get the size of a non alloc_size function")((void)0);
8524 const auto *Base = LVal.getLValueBase().get<const Expr *>();
8525 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
8526 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
8527}
8528
8529/// Attempts to evaluate the given LValueBase as the result of a call to
8530/// a function with the alloc_size attribute. If it was possible to do so, this
8531/// function will return true, make Result's Base point to said function call,
8532/// and mark Result's Base as invalid.
8533static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
8534 LValue &Result) {
8535 if (Base.isNull())
8536 return false;
8537
8538 // Because we do no form of static analysis, we only support const variables.
8539 //
8540 // Additionally, we can't support parameters, nor can we support static
8541 // variables (in the latter case, use-before-assign isn't UB; in the former,
8542 // we have no clue what they'll be assigned to).
8543 const auto *VD =
8544 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
8545 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
8546 return false;
8547
8548 const Expr *Init = VD->getAnyInitializer();
8549 if (!Init)
8550 return false;
8551
8552 const Expr *E = Init->IgnoreParens();
8553 if (!tryUnwrapAllocSizeCall(E))
8554 return false;
8555
8556 // Store E instead of E unwrapped so that the type of the LValue's base is
8557 // what the user wanted.
8558 Result.setInvalid(E);
8559
8560 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
8561 Result.addUnsizedArray(Info, E, Pointee);
8562 return true;
8563}
8564
8565namespace {
8566class PointerExprEvaluator
8567 : public ExprEvaluatorBase<PointerExprEvaluator> {
8568 LValue &Result;
8569 bool InvalidBaseOK;
8570
8571 bool Success(const Expr *E) {
8572 Result.set(E);
8573 return true;
8574 }
8575
8576 bool evaluateLValue(const Expr *E, LValue &Result) {
8577 return EvaluateLValue(E, Result, Info, InvalidBaseOK);
8578 }
8579
8580 bool evaluatePointer(const Expr *E, LValue &Result) {
8581 return EvaluatePointer(E, Result, Info, InvalidBaseOK);
8582 }
8583
8584 bool visitNonBuiltinCallExpr(const CallExpr *E);
8585public:
8586
8587 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
8588 : ExprEvaluatorBaseTy(info), Result(Result),
8589 InvalidBaseOK(InvalidBaseOK) {}
8590
8591 bool Success(const APValue &V, const Expr *E) {
8592 Result.setFrom(Info.Ctx, V);
8593 return true;
8594 }
8595 bool ZeroInitialization(const Expr *E) {
8596 Result.setNull(Info.Ctx, E->getType());
8597 return true;
8598 }
8599
8600 bool VisitBinaryOperator(const BinaryOperator *E);
8601 bool VisitCastExpr(const CastExpr* E);
8602 bool VisitUnaryAddrOf(const UnaryOperator *E);
8603 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
8604 { return Success(E); }
8605 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
8606 if (E->isExpressibleAsConstantInitializer())
8607 return Success(E);
8608 if (Info.noteFailure())
8609 EvaluateIgnoredValue(Info, E->getSubExpr());
8610 return Error(E);
8611 }
8612 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
8613 { return Success(E); }
8614 bool VisitCallExpr(const CallExpr *E);
8615 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
8616 bool VisitBlockExpr(const BlockExpr *E) {
8617 if (!E->getBlockDecl()->hasCaptures())
8618 return Success(E);
8619 return Error(E);
8620 }
8621 bool VisitCXXThisExpr(const CXXThisExpr *E) {
8622 // Can't look at 'this' when checking a potential constant expression.
8623 if (Info.checkingPotentialConstantExpression())
8624 return false;
8625 if (!Info.CurrentCall->This) {
8626 if (Info.getLangOpts().CPlusPlus11)
8627 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
8628 else
8629 Info.FFDiag(E);
8630 return false;
8631 }
8632 Result = *Info.CurrentCall->This;
8633 // If we are inside a lambda's call operator, the 'this' expression refers
8634 // to the enclosing '*this' object (either by value or reference) which is
8635 // either copied into the closure object's field that represents the '*this'
8636 // or refers to '*this'.
8637 if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
8638 // Ensure we actually have captured 'this'. (an error will have
8639 // been previously reported if not).
8640 if (!Info.CurrentCall->LambdaThisCaptureField)
8641 return false;
8642
8643 // Update 'Result' to refer to the data member/field of the closure object
8644 // that represents the '*this' capture.
8645 if (!HandleLValueMember(Info, E, Result,
8646 Info.CurrentCall->LambdaThisCaptureField))
8647 return false;
8648 // If we captured '*this' by reference, replace the field with its referent.
8649 if (Info.CurrentCall->LambdaThisCaptureField->getType()
8650 ->isPointerType()) {
8651 APValue RVal;
8652 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result,
8653 RVal))
8654 return false;
8655
8656 Result.setFrom(Info.Ctx, RVal);
8657 }
8658 }
8659 return true;
8660 }
8661
8662 bool VisitCXXNewExpr(const CXXNewExpr *E);
8663
8664 bool VisitSourceLocExpr(const SourceLocExpr *E) {
8665 assert(E->isStringType() && "SourceLocExpr isn't a pointer type?")((void)0);
8666 APValue LValResult = E->EvaluateInContext(
8667 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
8668 Result.setFrom(Info.Ctx, LValResult);
8669 return true;
8670 }
8671
8672 bool VisitSYCLUniqueStableNameExpr(const SYCLUniqueStableNameExpr *E) {
8673 std::string ResultStr = E->ComputeName(Info.Ctx);
8674
8675 Info.Ctx.SYCLUniqueStableNameEvaluatedValues[E] = ResultStr;
8676
8677 QualType CharTy = Info.Ctx.CharTy.withConst();
8678 APInt Size(Info.Ctx.getTypeSize(Info.Ctx.getSizeType()),
8679 ResultStr.size() + 1);
8680 QualType ArrayTy = Info.Ctx.getConstantArrayType(CharTy, Size, nullptr,
8681 ArrayType::Normal, 0);
8682
8683 StringLiteral *SL =
8684 StringLiteral::Create(Info.Ctx, ResultStr, StringLiteral::Ascii,
8685 /*Pascal*/ false, ArrayTy, E->getLocation());
8686
8687 evaluateLValue(SL, Result);
8688 Result.addArray(Info, E, cast<ConstantArrayType>(ArrayTy));
8689 return true;
8690 }
8691
8692 // FIXME: Missing: @protocol, @selector
8693};
8694} // end anonymous namespace
8695
8696static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
8697 bool InvalidBaseOK) {
8698 assert(!E->isValueDependent())((void)0);
8699 assert(E->isPRValue() && E->getType()->hasPointerRepresentation())((void)0);
8700 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8701}
8702
8703bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8704 if (E->getOpcode() != BO_Add &&
8705 E->getOpcode() != BO_Sub)
8706 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8707
8708 const Expr *PExp = E->getLHS();
8709 const Expr *IExp = E->getRHS();
8710 if (IExp->getType()->isPointerType())
8711 std::swap(PExp, IExp);
8712
8713 bool EvalPtrOK = evaluatePointer(PExp, Result);
8714 if (!EvalPtrOK && !Info.noteFailure())
8715 return false;
8716
8717 llvm::APSInt Offset;
8718 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
8719 return false;
8720
8721 if (E->getOpcode() == BO_Sub)
8722 negateAsSigned(Offset);
8723
8724 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
8725 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
8726}
8727
8728bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
8729 return evaluateLValue(E->getSubExpr(), Result);
8730}
8731
8732bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
8733 const Expr *SubExpr = E->getSubExpr();
8734
8735 switch (E->getCastKind()) {
8736 default:
8737 break;
8738 case CK_BitCast:
8739 case CK_CPointerToObjCPointerCast:
8740 case CK_BlockPointerToObjCPointerCast:
8741 case CK_AnyPointerToBlockPointerCast:
8742 case CK_AddressSpaceConversion:
8743 if (!Visit(SubExpr))
8744 return false;
8745 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
8746 // permitted in constant expressions in C++11. Bitcasts from cv void* are
8747 // also static_casts, but we disallow them as a resolution to DR1312.
8748 if (!E->getType()->isVoidPointerType()) {
8749 if (!Result.InvalidBase && !Result.Designator.Invalid &&
8750 !Result.IsNullPtr &&
8751 Info.Ctx.hasSameUnqualifiedType(Result.Designator.getType(Info.Ctx),
8752 E->getType()->getPointeeType()) &&
8753 Info.getStdAllocatorCaller("allocate")) {
8754 // Inside a call to std::allocator::allocate and friends, we permit
8755 // casting from void* back to cv1 T* for a pointer that points to a
8756 // cv2 T.
8757 } else {
8758 Result.Designator.setInvalid();
8759 if (SubExpr->getType()->isVoidPointerType())
8760 CCEDiag(E, diag::note_constexpr_invalid_cast)
8761 << 3 << SubExpr->getType();
8762 else
8763 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8764 }
8765 }
8766 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
8767 ZeroInitialization(E);
8768 return true;
8769
8770 case CK_DerivedToBase:
8771 case CK_UncheckedDerivedToBase:
8772 if (!evaluatePointer(E->getSubExpr(), Result))
8773 return false;
8774 if (!Result.Base && Result.Offset.isZero())
8775 return true;
8776
8777 // Now figure out the necessary offset to add to the base LV to get from
8778 // the derived class to the base class.
8779 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
8780 castAs<PointerType>()->getPointeeType(),
8781 Result);
8782
8783 case CK_BaseToDerived:
8784 if (!Visit(E->getSubExpr()))
8785 return false;
8786 if (!Result.Base && Result.Offset.isZero())
8787 return true;
8788 return HandleBaseToDerivedCast(Info, E, Result);
8789
8790 case CK_Dynamic:
8791 if (!Visit(E->getSubExpr()))
8792 return false;
8793 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
8794
8795 case CK_NullToPointer:
8796 VisitIgnoredValue(E->getSubExpr());
8797 return ZeroInitialization(E);
8798
8799 case CK_IntegralToPointer: {
8800 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8801
8802 APValue Value;
8803 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
8804 break;
8805
8806 if (Value.isInt()) {
8807 unsigned Size = Info.Ctx.getTypeSize(E->getType());
8808 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
8809 Result.Base = (Expr*)nullptr;
8810 Result.InvalidBase = false;
8811 Result.Offset = CharUnits::fromQuantity(N);
8812 Result.Designator.setInvalid();
8813 Result.IsNullPtr = false;
8814 return true;
8815 } else {
8816 // Cast is of an lvalue, no need to change value.
8817 Result.setFrom(Info.Ctx, Value);
8818 return true;
8819 }
8820 }
8821
8822 case CK_ArrayToPointerDecay: {
8823 if (SubExpr->isGLValue()) {
8824 if (!evaluateLValue(SubExpr, Result))
8825 return false;
8826 } else {
8827 APValue &Value = Info.CurrentCall->createTemporary(
8828 SubExpr, SubExpr->getType(), ScopeKind::FullExpression, Result);
8829 if (!EvaluateInPlace(Value, Info, Result, SubExpr))
8830 return false;
8831 }
8832 // The result is a pointer to the first element of the array.
8833 auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType());
8834 if (auto *CAT = dyn_cast<ConstantArrayType>(AT))
8835 Result.addArray(Info, E, CAT);
8836 else
8837 Result.addUnsizedArray(Info, E, AT->getElementType());
8838 return true;
8839 }
8840
8841 case CK_FunctionToPointerDecay:
8842 return evaluateLValue(SubExpr, Result);
8843
8844 case CK_LValueToRValue: {
8845 LValue LVal;
8846 if (!evaluateLValue(E->getSubExpr(), LVal))
8847 return false;
8848
8849 APValue RVal;
8850 // Note, we use the subexpression's type in order to retain cv-qualifiers.
8851 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
8852 LVal, RVal))
8853 return InvalidBaseOK &&
8854 evaluateLValueAsAllocSize(Info, LVal.Base, Result);
8855 return Success(RVal, E);
8856 }
8857 }
8858
8859 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8860}
8861
8862static CharUnits GetAlignOfType(EvalInfo &Info, QualType T,
8863 UnaryExprOrTypeTrait ExprKind) {
8864 // C++ [expr.alignof]p3:
8865 // When alignof is applied to a reference type, the result is the
8866 // alignment of the referenced type.
8867 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
8868 T = Ref->getPointeeType();
8869
8870 if (T.getQualifiers().hasUnaligned())
8871 return CharUnits::One();
8872
8873 const bool AlignOfReturnsPreferred =
8874 Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7;
8875
8876 // __alignof is defined to return the preferred alignment.
8877 // Before 8, clang returned the preferred alignment for alignof and _Alignof
8878 // as well.
8879 if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred)
8880 return Info.Ctx.toCharUnitsFromBits(
8881 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
8882 // alignof and _Alignof are defined to return the ABI alignment.
8883 else if (ExprKind == UETT_AlignOf)
8884 return Info.Ctx.getTypeAlignInChars(T.getTypePtr());
8885 else
8886 llvm_unreachable("GetAlignOfType on a non-alignment ExprKind")__builtin_unreachable();
8887}
8888
8889static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E,
8890 UnaryExprOrTypeTrait ExprKind) {
8891 E = E->IgnoreParens();
8892
8893 // The kinds of expressions that we have special-case logic here for
8894 // should be kept up to date with the special checks for those
8895 // expressions in Sema.
8896
8897 // alignof decl is always accepted, even if it doesn't make sense: we default
8898 // to 1 in those cases.
8899 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
8900 return Info.Ctx.getDeclAlign(DRE->getDecl(),
8901 /*RefAsPointee*/true);
8902
8903 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
8904 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
8905 /*RefAsPointee*/true);
8906
8907 return GetAlignOfType(Info, E->getType(), ExprKind);
8908}
8909
8910static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) {
8911 if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>())
8912 return Info.Ctx.getDeclAlign(VD);
8913 if (const auto *E = Value.Base.dyn_cast<const Expr *>())
8914 return GetAlignOfExpr(Info, E, UETT_AlignOf);
8915 return GetAlignOfType(Info, Value.Base.getTypeInfoType(), UETT_AlignOf);
8916}
8917
8918/// Evaluate the value of the alignment argument to __builtin_align_{up,down},
8919/// __builtin_is_aligned and __builtin_assume_aligned.
8920static bool getAlignmentArgument(const Expr *E, QualType ForType,
8921 EvalInfo &Info, APSInt &Alignment) {
8922 if (!EvaluateInteger(E, Alignment, Info))
8923 return false;
8924 if (Alignment < 0 || !Alignment.isPowerOf2()) {
8925 Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment;
8926 return false;
8927 }
8928 unsigned SrcWidth = Info.Ctx.getIntWidth(ForType);
8929 APSInt MaxValue(APInt::getOneBitSet(SrcWidth, SrcWidth - 1));
8930 if (APSInt::compareValues(Alignment, MaxValue) > 0) {
8931 Info.FFDiag(E, diag::note_constexpr_alignment_too_big)
8932 << MaxValue << ForType << Alignment;
8933 return false;
8934 }
8935 // Ensure both alignment and source value have the same bit width so that we
8936 // don't assert when computing the resulting value.
8937 APSInt ExtAlignment =
8938 APSInt(Alignment.zextOrTrunc(SrcWidth), /*isUnsigned=*/true);
8939 assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 &&((void)0)
8940 "Alignment should not be changed by ext/trunc")((void)0);
8941 Alignment = ExtAlignment;
8942 assert(Alignment.getBitWidth() == SrcWidth)((void)0);
8943 return true;
8944}
8945
8946// To be clear: this happily visits unsupported builtins. Better name welcomed.
8947bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
8948 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
8949 return true;
8950
8951 if (!(InvalidBaseOK && getAllocSizeAttr(E)))
8952 return false;
8953
8954 Result.setInvalid(E);
8955 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
8956 Result.addUnsizedArray(Info, E, PointeeTy);
8957 return true;
8958}
8959
8960bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
8961 if (IsStringLiteralCall(E))
8962 return Success(E);
8963
8964 if (unsigned BuiltinOp = E->getBuiltinCallee())
8965 return VisitBuiltinCallExpr(E, BuiltinOp);
8966
8967 return visitNonBuiltinCallExpr(E);
8968}
8969
8970// Determine if T is a character type for which we guarantee that
8971// sizeof(T) == 1.
8972static bool isOneByteCharacterType(QualType T) {
8973 return T->isCharType() || T->isChar8Type();
8974}
8975
8976bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
8977 unsigned BuiltinOp) {
8978 switch (BuiltinOp) {
8979 case Builtin::BI__builtin_addressof:
8980 return evaluateLValue(E->getArg(0), Result);
8981 case Builtin::BI__builtin_assume_aligned: {
8982 // We need to be very careful here because: if the pointer does not have the
8983 // asserted alignment, then the behavior is undefined, and undefined
8984 // behavior is non-constant.
8985 if (!evaluatePointer(E->getArg(0), Result))
8986 return false;
8987
8988 LValue OffsetResult(Result);
8989 APSInt Alignment;
8990 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
8991 Alignment))
8992 return false;
8993 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());
8994
8995 if (E->getNumArgs() > 2) {
8996 APSInt Offset;
8997 if (!EvaluateInteger(E->getArg(2), Offset, Info))
8998 return false;
8999
9000 int64_t AdditionalOffset = -Offset.getZExtValue();
9001 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
9002 }
9003
9004 // If there is a base object, then it must have the correct alignment.
9005 if (OffsetResult.Base) {
9006 CharUnits BaseAlignment = getBaseAlignment(Info, OffsetResult);
9007
9008 if (BaseAlignment < Align) {
9009 Result.Designator.setInvalid();
9010 // FIXME: Add support to Diagnostic for long / long long.
9011 CCEDiag(E->getArg(0),
9012 diag::note_constexpr_baa_insufficient_alignment) << 0
9013 << (unsigned)BaseAlignment.getQuantity()
9014 << (unsigned)Align.getQuantity();
9015 return false;
9016 }
9017 }
9018
9019 // The offset must also have the correct alignment.
9020 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
9021 Result.Designator.setInvalid();
9022
9023 (OffsetResult.Base
9024 ? CCEDiag(E->getArg(0),
9025 diag::note_constexpr_baa_insufficient_alignment) << 1
9026 : CCEDiag(E->getArg(0),
9027 diag::note_constexpr_baa_value_insufficient_alignment))
9028 << (int)OffsetResult.Offset.getQuantity()
9029 << (unsigned)Align.getQuantity();
9030 return false;
9031 }
9032
9033 return true;
9034 }
9035 case Builtin::BI__builtin_align_up:
9036 case Builtin::BI__builtin_align_down: {
9037 if (!evaluatePointer(E->getArg(0), Result))
9038 return false;
9039 APSInt Alignment;
9040 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
9041 Alignment))
9042 return false;
9043 CharUnits BaseAlignment = getBaseAlignment(Info, Result);
9044 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Result.Offset);
9045 // For align_up/align_down, we can return the same value if the alignment
9046 // is known to be greater or equal to the requested value.
9047 if (PtrAlign.getQuantity() >= Alignment)
9048 return true;
9049
9050 // The alignment could be greater than the minimum at run-time, so we cannot
9051 // infer much about the resulting pointer value. One case is possible:
9052 // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we
9053 // can infer the correct index if the requested alignment is smaller than
9054 // the base alignment so we can perform the computation on the offset.
9055 if (BaseAlignment.getQuantity() >= Alignment) {
9056 assert(Alignment.getBitWidth() <= 64 &&((void)0)
9057 "Cannot handle > 64-bit address-space")((void)0);
9058 uint64_t Alignment64 = Alignment.getZExtValue();
9059 CharUnits NewOffset = CharUnits::fromQuantity(
9060 BuiltinOp == Builtin::BI__builtin_align_down
9061 ? llvm::alignDown(Result.Offset.getQuantity(), Alignment64)
9062 : llvm::alignTo(Result.Offset.getQuantity(), Alignment64));
9063 Result.adjustOffset(NewOffset - Result.Offset);
9064 // TODO: diagnose out-of-bounds values/only allow for arrays?
9065 return true;
9066 }
9067 // Otherwise, we cannot constant-evaluate the result.
9068 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust)
9069 << Alignment;
9070 return false;
9071 }
9072 case Builtin::BI__builtin_operator_new:
9073 return HandleOperatorNewCall(Info, E, Result);
9074 case Builtin::BI__builtin_launder:
9075 return evaluatePointer(E->getArg(0), Result);
9076 case Builtin::BIstrchr:
9077 case Builtin::BIwcschr:
9078 case Builtin::BImemchr:
9079 case Builtin::BIwmemchr:
9080 if (Info.getLangOpts().CPlusPlus11)
9081 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
9082 << /*isConstexpr*/0 << /*isConstructor*/0
9083 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
9084 else
9085 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
9086 LLVM_FALLTHROUGH[[gnu::fallthrough]];
9087 case Builtin::BI__builtin_strchr:
9088 case Builtin::BI__builtin_wcschr:
9089 case Builtin::BI__builtin_memchr:
9090 case Builtin::BI__builtin_char_memchr:
9091 case Builtin::BI__builtin_wmemchr: {
9092 if (!Visit(E->getArg(0)))
9093 return false;
9094 APSInt Desired;
9095 if (!EvaluateInteger(E->getArg(1), Desired, Info))
9096 return false;
9097 uint64_t MaxLength = uint64_t(-1);
9098 if (BuiltinOp != Builtin::BIstrchr &&
9099 BuiltinOp != Builtin::BIwcschr &&
9100 BuiltinOp != Builtin::BI__builtin_strchr &&
9101 BuiltinOp != Builtin::BI__builtin_wcschr) {
9102 APSInt N;
9103 if (!EvaluateInteger(E->getArg(2), N, Info))
9104 return false;
9105 MaxLength = N.getExtValue();
9106 }
9107 // We cannot find the value if there are no candidates to match against.
9108 if (MaxLength == 0u)
9109 return ZeroInitialization(E);
9110 if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
9111 Result.Designator.Invalid)
9112 return false;
9113 QualType CharTy = Result.Designator.getType(Info.Ctx);
9114 bool IsRawByte = BuiltinOp == Builtin::BImemchr ||
9115 BuiltinOp == Builtin::BI__builtin_memchr;
9116 assert(IsRawByte ||((void)0)
9117 Info.Ctx.hasSameUnqualifiedType(((void)0)
9118 CharTy, E->getArg(0)->getType()->getPointeeType()))((void)0);
9119 // Pointers to const void may point to objects of incomplete type.
9120 if (IsRawByte && CharTy->isIncompleteType()) {
9121 Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy;
9122 return false;
9123 }
9124 // Give up on byte-oriented matching against multibyte elements.
9125 // FIXME: We can compare the bytes in the correct order.
9126 if (IsRawByte && !isOneByteCharacterType(CharTy)) {
9127 Info.FFDiag(E, diag::note_constexpr_memchr_unsupported)
9128 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
9129 << CharTy;
9130 return false;
9131 }
9132 // Figure out what value we're actually looking for (after converting to
9133 // the corresponding unsigned type if necessary).
9134 uint64_t DesiredVal;
9135 bool StopAtNull = false;
9136 switch (BuiltinOp) {
9137 case Builtin::BIstrchr:
9138 case Builtin::BI__builtin_strchr:
9139 // strchr compares directly to the passed integer, and therefore
9140 // always fails if given an int that is not a char.
9141 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
9142 E->getArg(1)->getType(),
9143 Desired),
9144 Desired))
9145 return ZeroInitialization(E);
9146 StopAtNull = true;
9147 LLVM_FALLTHROUGH[[gnu::fallthrough]];
9148 case Builtin::BImemchr:
9149 case Builtin::BI__builtin_memchr:
9150 case Builtin::BI__builtin_char_memchr:
9151 // memchr compares by converting both sides to unsigned char. That's also
9152 // correct for strchr if we get this far (to cope with plain char being
9153 // unsigned in the strchr case).
9154 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
9155 break;
9156
9157 case Builtin::BIwcschr:
9158 case Builtin::BI__builtin_wcschr:
9159 StopAtNull = true;
9160 LLVM_FALLTHROUGH[[gnu::fallthrough]];
9161 case Builtin::BIwmemchr:
9162 case Builtin::BI__builtin_wmemchr:
9163 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
9164 DesiredVal = Desired.getZExtValue();
9165 break;
9166 }
9167
9168 for (; MaxLength; --MaxLength) {
9169 APValue Char;
9170 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
9171 !Char.isInt())
9172 return false;
9173 if (Char.getInt().getZExtValue() == DesiredVal)
9174 return true;
9175 if (StopAtNull && !Char.getInt())
9176 break;
9177 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
9178 return false;
9179 }
9180 // Not found: return nullptr.
9181 return ZeroInitialization(E);
9182 }
9183
9184 case Builtin::BImemcpy:
9185 case Builtin::BImemmove:
9186 case Builtin::BIwmemcpy:
9187 case Builtin::BIwmemmove:
9188 if (Info.getLangOpts().CPlusPlus11)
9189 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
9190 << /*isConstexpr*/0 << /*isConstructor*/0
9191 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
9192 else
9193 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
9194 LLVM_FALLTHROUGH[[gnu::fallthrough]];
9195 case Builtin::BI__builtin_memcpy:
9196 case Builtin::BI__builtin_memmove:
9197 case Builtin::BI__builtin_wmemcpy:
9198 case Builtin::BI__builtin_wmemmove: {
9199 bool WChar = BuiltinOp == Builtin::BIwmemcpy ||
9200 BuiltinOp == Builtin::BIwmemmove ||
9201 BuiltinOp == Builtin::BI__builtin_wmemcpy ||
9202 BuiltinOp == Builtin::BI__builtin_wmemmove;
9203 bool Move = BuiltinOp == Builtin::BImemmove ||
9204 BuiltinOp == Builtin::BIwmemmove ||
9205 BuiltinOp == Builtin::BI__builtin_memmove ||
9206 BuiltinOp == Builtin::BI__builtin_wmemmove;
9207
9208 // The result of mem* is the first argument.
9209 if (!Visit(E->getArg(0)))
9210 return false;
9211 LValue Dest = Result;
9212
9213 LValue Src;
9214 if (!EvaluatePointer(E->getArg(1), Src, Info))
9215 return false;
9216
9217 APSInt N;
9218 if (!EvaluateInteger(E->getArg(2), N, Info))
9219 return false;
9220 assert(!N.isSigned() && "memcpy and friends take an unsigned size")((void)0);
9221
9222 // If the size is zero, we treat this as always being a valid no-op.
9223 // (Even if one of the src and dest pointers is null.)
9224 if (!N)
9225 return true;
9226
9227 // Otherwise, if either of the operands is null, we can't proceed. Don't
9228 // try to determine the type of the copied objects, because there aren't
9229 // any.
9230 if (!Src.Base || !Dest.Base) {
9231 APValue Val;
9232 (!Src.Base ? Src : Dest).moveInto(Val);
9233 Info.FFDiag(E, diag::note_constexpr_memcpy_null)
9234 << Move << WChar << !!Src.Base
9235 << Val.getAsString(Info.Ctx, E->getArg(0)->getType());
9236 return false;
9237 }
9238 if (Src.Designator.Invalid || Dest.Designator.Invalid)
9239 return false;
9240
9241 // We require that Src and Dest are both pointers to arrays of
9242 // trivially-copyable type. (For the wide version, the designator will be
9243 // invalid if the designated object is not a wchar_t.)
9244 QualType T = Dest.Designator.getType(Info.Ctx);
9245 QualType SrcT = Src.Designator.getType(Info.Ctx);
9246 if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) {
9247 // FIXME: Consider using our bit_cast implementation to support this.
9248 Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T;
9249 return false;
9250 }
9251 if (T->isIncompleteType()) {
9252 Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T;
9253 return false;
9254 }
9255 if (!T.isTriviallyCopyableType(Info.Ctx)) {
9256 Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T;
9257 return false;
9258 }
9259
9260 // Figure out how many T's we're copying.
9261 uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity();
9262 if (!WChar) {
9263 uint64_t Remainder;
9264 llvm::APInt OrigN = N;
9265 llvm::APInt::udivrem(OrigN, TSize, N, Remainder);
9266 if (Remainder) {
9267 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
9268 << Move << WChar << 0 << T << toString(OrigN, 10, /*Signed*/false)
9269 << (unsigned)TSize;
9270 return false;
9271 }
9272 }
9273
9274 // Check that the copying will remain within the arrays, just so that we
9275 // can give a more meaningful diagnostic. This implicitly also checks that
9276 // N fits into 64 bits.
9277 uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second;
9278 uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second;
9279 if (N.ugt(RemainingSrcSize) || N.ugt(RemainingDestSize)) {
9280 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
9281 << Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T
9282 << toString(N, 10, /*Signed*/false);
9283 return false;
9284 }
9285 uint64_t NElems = N.getZExtValue();
9286 uint64_t NBytes = NElems * TSize;
9287
9288 // Check for overlap.
9289 int Direction = 1;
9290 if (HasSameBase(Src, Dest)) {
9291 uint64_t SrcOffset = Src.getLValueOffset().getQuantity();
9292 uint64_t DestOffset = Dest.getLValueOffset().getQuantity();
9293 if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) {
9294 // Dest is inside the source region.
9295 if (!Move) {
9296 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
9297 return false;
9298 }
9299 // For memmove and friends, copy backwards.
9300 if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) ||
9301 !HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1))
9302 return false;
9303 Direction = -1;
9304 } else if (!Move && SrcOffset >= DestOffset &&
9305 SrcOffset - DestOffset < NBytes) {
9306 // Src is inside the destination region for memcpy: invalid.
9307 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
9308 return false;
9309 }
9310 }
9311
9312 while (true) {
9313 APValue Val;
9314 // FIXME: Set WantObjectRepresentation to true if we're copying a
9315 // char-like type?
9316 if (!handleLValueToRValueConversion(Info, E, T, Src, Val) ||
9317 !handleAssignment(Info, E, Dest, T, Val))
9318 return false;
9319 // Do not iterate past the last element; if we're copying backwards, that
9320 // might take us off the start of the array.
9321 if (--NElems == 0)
9322 return true;
9323 if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) ||
9324 !HandleLValueArrayAdjustment(Info, E, Dest, T, Direction))
9325 return false;
9326 }
9327 }
9328
9329 default:
9330 break;
9331 }
9332
9333 return visitNonBuiltinCallExpr(E);
9334}
9335
9336static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
9337 APValue &Result, const InitListExpr *ILE,
9338 QualType AllocType);
9339static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
9340 APValue &Result,
9341 const CXXConstructExpr *CCE,
9342 QualType AllocType);
9343
9344bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
9345 if (!Info.getLangOpts().CPlusPlus20)
9346 Info.CCEDiag(E, diag::note_constexpr_new);
9347
9348 // We cannot speculatively evaluate a delete expression.
9349 if (Info.SpeculativeEvaluationDepth)
9350 return false;
9351
9352 FunctionDecl *OperatorNew = E->getOperatorNew();
9353
9354 bool IsNothrow = false;
9355 bool IsPlacement = false;
9356 if (OperatorNew->isReservedGlobalPlacementOperator() &&
9357 Info.CurrentCall->isStdFunction() && !E->isArray()) {
9358 // FIXME Support array placement new.
9359 assert(E->getNumPlacementArgs() == 1)((void)0);
9360 if (!EvaluatePointer(E->getPlacementArg(0), Result, Info))
9361 return false;
9362 if (Result.Designator.Invalid)
9363 return false;
9364 IsPlacement = true;
9365 } else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) {
9366 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
9367 << isa<CXXMethodDecl>(OperatorNew) << OperatorNew;
9368 return false;
9369 } else if (E->getNumPlacementArgs()) {
9370 // The only new-placement list we support is of the form (std::nothrow).
9371 //
9372 // FIXME: There is no restriction on this, but it's not clear that any
9373 // other form makes any sense. We get here for cases such as:
9374 //
9375 // new (std::align_val_t{N}) X(int)
9376 //
9377 // (which should presumably be valid only if N is a multiple of
9378 // alignof(int), and in any case can't be deallocated unless N is
9379 // alignof(X) and X has new-extended alignment).
9380 if (E->getNumPlacementArgs() != 1 ||
9381 !E->getPlacementArg(0)->getType()->isNothrowT())
9382 return Error(E, diag::note_constexpr_new_placement);
9383
9384 LValue Nothrow;
9385 if (!EvaluateLValue(E->getPlacementArg(0), Nothrow, Info))
9386 return false;
9387 IsNothrow = true;
9388 }
9389
9390 const Expr *Init = E->getInitializer();
9391 const InitListExpr *ResizedArrayILE = nullptr;
9392 const CXXConstructExpr *ResizedArrayCCE = nullptr;
9393 bool ValueInit = false;
9394
9395 QualType AllocType = E->getAllocatedType();
9396 if (Optional<const Expr*> ArraySize = E->getArraySize()) {
9397 const Expr *Stripped = *ArraySize;
9398 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Stripped);
9399 Stripped = ICE->getSubExpr())
9400 if (ICE->getCastKind() != CK_NoOp &&
9401 ICE->getCastKind() != CK_IntegralCast)
9402 break;
9403
9404 llvm::APSInt ArrayBound;
9405 if (!EvaluateInteger(Stripped, ArrayBound, Info))
9406 return false;
9407
9408 // C++ [expr.new]p9:
9409 // The expression is erroneous if:
9410 // -- [...] its value before converting to size_t [or] applying the
9411 // second standard conversion sequence is less than zero
9412 if (ArrayBound.isSigned() && ArrayBound.isNegative()) {
9413 if (IsNothrow)
9414 return ZeroInitialization(E);
9415
9416 Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative)
9417 << ArrayBound << (*ArraySize)->getSourceRange();
9418 return false;
9419 }
9420
9421 // -- its value is such that the size of the allocated object would
9422 // exceed the implementation-defined limit
9423 if (ConstantArrayType::getNumAddressingBits(Info.Ctx, AllocType,
9424 ArrayBound) >
9425 ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
9426 if (IsNothrow)
9427 return ZeroInitialization(E);
9428
9429 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_large)
9430 << ArrayBound << (*ArraySize)->getSourceRange();
9431 return false;
9432 }
9433
9434 // -- the new-initializer is a braced-init-list and the number of
9435 // array elements for which initializers are provided [...]
9436 // exceeds the number of elements to initialize
9437 if (!Init) {
9438 // No initialization is performed.
9439 } else if (isa<CXXScalarValueInitExpr>(Init) ||
9440 isa<ImplicitValueInitExpr>(Init)) {
9441 ValueInit = true;
9442 } else if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) {
9443 ResizedArrayCCE = CCE;
9444 } else {
9445 auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType());
9446 assert(CAT && "unexpected type for array initializer")((void)0);
9447
9448 unsigned Bits =
9449 std::max(CAT->getSize().getBitWidth(), ArrayBound.getBitWidth());
9450 llvm::APInt InitBound = CAT->getSize().zextOrSelf(Bits);
9451 llvm::APInt AllocBound = ArrayBound.zextOrSelf(Bits);
9452 if (InitBound.ugt(AllocBound)) {
9453 if (IsNothrow)
9454 return ZeroInitialization(E);
9455
9456 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small)
9457 << toString(AllocBound, 10, /*Signed=*/false)
9458 << toString(InitBound, 10, /*Signed=*/false)
9459 << (*ArraySize)->getSourceRange();
9460 return false;
9461 }
9462
9463 // If the sizes differ, we must have an initializer list, and we need
9464 // special handling for this case when we initialize.
9465 if (InitBound != AllocBound)
9466 ResizedArrayILE = cast<InitListExpr>(Init);
9467 }
9468
9469 AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr,
9470 ArrayType::Normal, 0);
9471 } else {
9472 assert(!AllocType->isArrayType() &&((void)0)
9473 "array allocation with non-array new")((void)0);
9474 }
9475
9476 APValue *Val;
9477 if (IsPlacement) {
9478 AccessKinds AK = AK_Construct;
9479 struct FindObjectHandler {
9480 EvalInfo &Info;
9481 const Expr *E;
9482 QualType AllocType;
9483 const AccessKinds AccessKind;
9484 APValue *Value;
9485
9486 typedef bool result_type;
9487 bool failed() { return false; }
9488 bool found(APValue &Subobj, QualType SubobjType) {
9489 // FIXME: Reject the cases where [basic.life]p8 would not permit the
9490 // old name of the object to be used to name the new object.
9491 if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) {
9492 Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) <<
9493 SubobjType << AllocType;
9494 return false;
9495 }
9496 Value = &Subobj;
9497 return true;
9498 }
9499 bool found(APSInt &Value, QualType SubobjType) {
9500 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
9501 return false;
9502 }
9503 bool found(APFloat &Value, QualType SubobjType) {
9504 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
9505 return false;
9506 }
9507 } Handler = {Info, E, AllocType, AK, nullptr};
9508
9509 CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType);
9510 if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler))
9511 return false;
9512
9513 Val = Handler.Value;
9514
9515 // [basic.life]p1:
9516 // The lifetime of an object o of type T ends when [...] the storage
9517 // which the object occupies is [...] reused by an object that is not
9518 // nested within o (6.6.2).
9519 *Val = APValue();
9520 } else {
9521 // Perform the allocation and obtain a pointer to the resulting object.
9522 Val = Info.createHeapAlloc(E, AllocType, Result);
9523 if (!Val)
9524 return false;
9525 }
9526
9527 if (ValueInit) {
9528 ImplicitValueInitExpr VIE(AllocType);
9529 if (!EvaluateInPlace(*Val, Info, Result, &VIE))
9530 return false;
9531 } else if (ResizedArrayILE) {
9532 if (!EvaluateArrayNewInitList(Info, Result, *Val, ResizedArrayILE,
9533 AllocType))
9534 return false;
9535 } else if (ResizedArrayCCE) {
9536 if (!EvaluateArrayNewConstructExpr(Info, Result, *Val, ResizedArrayCCE,
9537 AllocType))
9538 return false;
9539 } else if (Init) {
9540 if (!EvaluateInPlace(*Val, Info, Result, Init))
9541 return false;
9542 } else if (!getDefaultInitValue(AllocType, *Val)) {
9543 return false;
9544 }
9545
9546 // Array new returns a pointer to the first element, not a pointer to the
9547 // array.
9548 if (auto *AT = AllocType->getAsArrayTypeUnsafe())
9549 Result.addArray(Info, E, cast<ConstantArrayType>(AT));
9550
9551 return true;
9552}
9553//===----------------------------------------------------------------------===//
9554// Member Pointer Evaluation
9555//===----------------------------------------------------------------------===//
9556
9557namespace {
9558class MemberPointerExprEvaluator
9559 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
9560 MemberPtr &Result;
9561
9562 bool Success(const ValueDecl *D) {
9563 Result = MemberPtr(D);
9564 return true;
9565 }
9566public:
9567
9568 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
9569 : ExprEvaluatorBaseTy(Info), Result(Result) {}
9570
9571 bool Success(const APValue &V, const Expr *E) {
9572 Result.setFrom(V);
9573 return true;
9574 }
9575 bool ZeroInitialization(const Expr *E) {
9576 return Success((const ValueDecl*)nullptr);
9577 }
9578
9579 bool VisitCastExpr(const CastExpr *E);
9580 bool VisitUnaryAddrOf(const UnaryOperator *E);
9581};
9582} // end anonymous namespace
9583
9584static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
9585 EvalInfo &Info) {
9586 assert(!E->isValueDependent())((void)0);
9587 assert(E->isPRValue() && E->getType()->isMemberPointerType())((void)0);
9588 return MemberPointerExprEvaluator(Info, Result).Visit(E);
9589}
9590
9591bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
9592 switch (E->getCastKind()) {
9593 default:
9594 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9595
9596 case CK_NullToMemberPointer:
9597 VisitIgnoredValue(E->getSubExpr());
9598 return ZeroInitialization(E);
9599
9600 case CK_BaseToDerivedMemberPointer: {
9601 if (!Visit(E->getSubExpr()))
9602 return false;
9603 if (E->path_empty())
9604 return true;
9605 // Base-to-derived member pointer casts store the path in derived-to-base
9606 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
9607 // the wrong end of the derived->base arc, so stagger the path by one class.
9608 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
9609 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
9610 PathI != PathE; ++PathI) {
9611 assert(!(*PathI)->isVirtual() && "memptr cast through vbase")((void)0);
9612 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
9613 if (!Result.castToDerived(Derived))
9614 return Error(E);
9615 }
9616 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
9617 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
9618 return Error(E);
9619 return true;
9620 }
9621
9622 case CK_DerivedToBaseMemberPointer:
9623 if (!Visit(E->getSubExpr()))
9624 return false;
9625 for (CastExpr::path_const_iterator PathI = E->path_begin(),
9626 PathE = E->path_end(); PathI != PathE; ++PathI) {
9627 assert(!(*PathI)->isVirtual() && "memptr cast through vbase")((void)0);
9628 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
9629 if (!Result.castToBase(Base))
9630 return Error(E);
9631 }
9632 return true;
9633 }
9634}
9635
9636bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
9637 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
9638 // member can be formed.
9639 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
9640}
9641
9642//===----------------------------------------------------------------------===//
9643// Record Evaluation
9644//===----------------------------------------------------------------------===//
9645
9646namespace {
9647 class RecordExprEvaluator
9648 : public ExprEvaluatorBase<RecordExprEvaluator> {
9649 const LValue &This;
9650 APValue &Result;
9651 public:
9652
9653 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
9654 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
9655
9656 bool Success(const APValue &V, const Expr *E) {
9657 Result = V;
9658 return true;
9659 }
9660 bool ZeroInitialization(const Expr *E) {
9661 return ZeroInitialization(E, E->getType());
9662 }
9663 bool ZeroInitialization(const Expr *E, QualType T);
9664
9665 bool VisitCallExpr(const CallExpr *E) {
9666 return handleCallExpr(E, Result, &This);
9667 }
9668 bool VisitCastExpr(const CastExpr *E);
9669 bool VisitInitListExpr(const InitListExpr *E);
9670 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
9671 return VisitCXXConstructExpr(E, E->getType());
9672 }
9673 bool VisitLambdaExpr(const LambdaExpr *E);
9674 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
9675 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
9676 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
9677 bool VisitBinCmp(const BinaryOperator *E);
9678 };
9679}
9680
9681/// Perform zero-initialization on an object of non-union class type.
9682/// C++11 [dcl.init]p5:
9683/// To zero-initialize an object or reference of type T means:
9684/// [...]
9685/// -- if T is a (possibly cv-qualified) non-union class type,
9686/// each non-static data member and each base-class subobject is
9687/// zero-initialized
9688static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
9689 const RecordDecl *RD,
9690 const LValue &This, APValue &Result) {
9691 assert(!RD->isUnion() && "Expected non-union class type")((void)0);
9692 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
9693 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
9694 std::distance(RD->field_begin(), RD->field_end()));
9695
9696 if (RD->isInvalidDecl()) return false;
9697 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
9698
9699 if (CD) {
9700 unsigned Index = 0;
9701 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
9702 End = CD->bases_end(); I != End; ++I, ++Index) {
9703 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
9704 LValue Subobject = This;
9705 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
9706 return false;
9707 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
9708 Result.getStructBase(Index)))
9709 return false;
9710 }
9711 }
9712
9713 for (const auto *I : RD->fields()) {
9714 // -- if T is a reference type, no initialization is performed.
9715 if (I->isUnnamedBitfield() || I->getType()->isReferenceType())
9716 continue;
9717
9718 LValue Subobject = This;
9719 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
9720 return false;
9721
9722 ImplicitValueInitExpr VIE(I->getType());
9723 if (!EvaluateInPlace(
9724 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
9725 return false;
9726 }
9727
9728 return true;
9729}
9730
9731bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
9732 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
9733 if (RD->isInvalidDecl()) return false;
9734 if (RD->isUnion()) {
9735 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
9736 // object's first non-static named data member is zero-initialized
9737 RecordDecl::field_iterator I = RD->field_begin();
9738 while (I != RD->field_end() && (*I)->isUnnamedBitfield())
9739 ++I;
9740 if (I == RD->field_end()) {
9741 Result = APValue((const FieldDecl*)nullptr);
9742 return true;
9743 }
9744
9745 LValue Subobject = This;
9746 if (!HandleLValueMember(Info, E, Subobject, *I))
9747 return false;
9748 Result = APValue(*I);
9749 ImplicitValueInitExpr VIE(I->getType());
9750 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
9751 }
9752
9753 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
9754 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
9755 return false;
9756 }
9757
9758 return HandleClassZeroInitialization(Info, E, RD, This, Result);
9759}
9760
9761bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
9762 switch (E->getCastKind()) {
9763 default:
9764 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9765
9766 case CK_ConstructorConversion:
9767 return Visit(E->getSubExpr());
9768
9769 case CK_DerivedToBase:
9770 case CK_UncheckedDerivedToBase: {
9771 APValue DerivedObject;
9772 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
9773 return false;
9774 if (!DerivedObject.isStruct())
9775 return Error(E->getSubExpr());
9776
9777 // Derived-to-base rvalue conversion: just slice off the derived part.
9778 APValue *Value = &DerivedObject;
9779 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
9780 for (CastExpr::path_const_iterator PathI = E->path_begin(),
9781 PathE = E->path_end(); PathI != PathE; ++PathI) {
9782 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base")((void)0);
9783 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
9784 Value = &Value->getStructBase(getBaseIndex(RD, Base));
9785 RD = Base;
9786 }
9787 Result = *Value;
9788 return true;
9789 }
9790 }
9791}
9792
9793bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9794 if (E->isTransparent())
9795 return Visit(E->getInit(0));
9796
9797 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
9798 if (RD->isInvalidDecl()) return false;
9799 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
9800 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
9801
9802 EvalInfo::EvaluatingConstructorRAII EvalObj(
9803 Info,
9804 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
9805 CXXRD && CXXRD->getNumBases());
9806
9807 if (RD->isUnion()) {
9808 const FieldDecl *Field = E->getInitializedFieldInUnion();
9809 Result = APValue(Field);
9810 if (!Field)
9811 return true;
9812
9813 // If the initializer list for a union does not contain any elements, the
9814 // first element of the union is value-initialized.
9815 // FIXME: The element should be initialized from an initializer list.
9816 // Is this difference ever observable for initializer lists which
9817 // we don't build?
9818 ImplicitValueInitExpr VIE(Field->getType());
9819 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
9820
9821 LValue Subobject = This;
9822 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
9823 return false;
9824
9825 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
9826 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
9827 isa<CXXDefaultInitExpr>(InitExpr));
9828
9829 if (EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr)) {
9830 if (Field->isBitField())
9831 return truncateBitfieldValue(Info, InitExpr, Result.getUnionValue(),
9832 Field);
9833 return true;
9834 }
9835
9836 return false;
9837 }
9838
9839 if (!Result.hasValue())
9840 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
9841 std::distance(RD->field_begin(), RD->field_end()));
9842 unsigned ElementNo = 0;
9843 bool Success = true;
9844
9845 // Initialize base classes.
9846 if (CXXRD && CXXRD->getNumBases()) {
9847 for (const auto &Base : CXXRD->bases()) {
9848 assert(ElementNo < E->getNumInits() && "missing init for base class")((void)0);
9849 const Expr *Init = E->getInit(ElementNo);
9850
9851 LValue Subobject = This;
9852 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
9853 return false;
9854
9855 APValue &FieldVal = Result.getStructBase(ElementNo);
9856 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
9857 if (!Info.noteFailure())
9858 return false;
9859 Success = false;
9860 }
9861 ++ElementNo;
9862 }
9863
9864 EvalObj.finishedConstructingBases();
9865 }
9866
9867 // Initialize members.
9868 for (const auto *Field : RD->fields()) {
9869 // Anonymous bit-fields are not considered members of the class for
9870 // purposes of aggregate initialization.
9871 if (Field->isUnnamedBitfield())
9872 continue;
9873
9874 LValue Subobject = This;
9875
9876 bool HaveInit = ElementNo < E->getNumInits();
9877
9878 // FIXME: Diagnostics here should point to the end of the initializer
9879 // list, not the start.
9880 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
9881 Subobject, Field, &Layout))
9882 return false;
9883
9884 // Perform an implicit value-initialization for members beyond the end of
9885 // the initializer list.
9886 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
9887 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
9888
9889 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
9890 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
9891 isa<CXXDefaultInitExpr>(Init));
9892
9893 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
9894 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
9895 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
9896 FieldVal, Field))) {
9897 if (!Info.noteFailure())
9898 return false;
9899 Success = false;
9900 }
9901 }
9902
9903 EvalObj.finishedConstructingFields();
9904
9905 return Success;
9906}
9907
9908bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
9909 QualType T) {
9910 // Note that E's type is not necessarily the type of our class here; we might
9911 // be initializing an array element instead.
9912 const CXXConstructorDecl *FD = E->getConstructor();
9913 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
9914
9915 bool ZeroInit = E->requiresZeroInitialization();
9916 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
9917 // If we've already performed zero-initialization, we're already done.
9918 if (Result.hasValue())
9919 return true;
9920
9921 if (ZeroInit)
9922 return ZeroInitialization(E, T);
9923
9924 return getDefaultInitValue(T, Result);
9925 }
9926
9927 const FunctionDecl *Definition = nullptr;
9928 auto Body = FD->getBody(Definition);
9929
9930 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
9931 return false;
9932
9933 // Avoid materializing a temporary for an elidable copy/move constructor.
9934 if (E->isElidable() && !ZeroInit) {
9935 // FIXME: This only handles the simplest case, where the source object
9936 // is passed directly as the first argument to the constructor.
9937 // This should also handle stepping though implicit casts and
9938 // and conversion sequences which involve two steps, with a
9939 // conversion operator followed by a converting constructor.
9940 const Expr *SrcObj = E->getArg(0);
9941 assert(SrcObj->isTemporaryObject(Info.Ctx, FD->getParent()))((void)0);
9942 assert(Info.Ctx.hasSameUnqualifiedType(E->getType(), SrcObj->getType()))((void)0);
9943 if (const MaterializeTemporaryExpr *ME =
9944 dyn_cast<MaterializeTemporaryExpr>(SrcObj))
9945 return Visit(ME->getSubExpr());
9946 }
9947
9948 if (ZeroInit && !ZeroInitialization(E, T))
9949 return false;
9950
9951 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
9952 return HandleConstructorCall(E, This, Args,
9953 cast<CXXConstructorDecl>(Definition), Info,
9954 Result);
9955}
9956
9957bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
9958 const CXXInheritedCtorInitExpr *E) {
9959 if (!Info.CurrentCall) {
9960 assert(Info.checkingPotentialConstantExpression())((void)0);
9961 return false;
9962 }
9963
9964 const CXXConstructorDecl *FD = E->getConstructor();
9965 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
9966 return false;
9967
9968 const FunctionDecl *Definition = nullptr;
9969 auto Body = FD->getBody(Definition);
9970
9971 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
9972 return false;
9973
9974 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
9975 cast<CXXConstructorDecl>(Definition), Info,
9976 Result);
9977}
9978
9979bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
9980 const CXXStdInitializerListExpr *E) {
9981 const ConstantArrayType *ArrayType =
9982 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
9983
9984 LValue Array;
9985 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
9986 return false;
9987
9988 // Get a pointer to the first element of the array.
9989 Array.addArray(Info, E, ArrayType);
9990
9991 auto InvalidType = [&] {
9992 Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
9993 << E->getType();
9994 return false;
9995 };
9996
9997 // FIXME: Perform the checks on the field types in SemaInit.
9998 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
9999 RecordDecl::field_iterator Field = Record->field_begin();
10000 if (Field == Record->field_end())
10001 return InvalidType();
10002
10003 // Start pointer.
10004 if (!Field->getType()->isPointerType() ||
10005 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
10006 ArrayType->getElementType()))
10007 return InvalidType();
10008
10009 // FIXME: What if the initializer_list type has base classes, etc?
10010 Result = APValue(APValue::UninitStruct(), 0, 2);
10011 Array.moveInto(Result.getStructField(0));
10012
10013 if (++Field == Record->field_end())
10014 return InvalidType();
10015
10016 if (Field->getType()->isPointerType() &&
10017 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
10018 ArrayType->getElementType())) {
10019 // End pointer.
10020 if (!HandleLValueArrayAdjustment(Info, E, Array,
10021 ArrayType->getElementType(),
10022 ArrayType->getSize().getZExtValue()))
10023 return false;
10024 Array.moveInto(Result.getStructField(1));
10025 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
10026 // Length.
10027 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
10028 else
10029 return InvalidType();
10030
10031 if (++Field != Record->field_end())
10032 return InvalidType();
10033
10034 return true;
10035}
10036
10037bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
10038 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
10039 if (ClosureClass->isInvalidDecl())
10040 return false;
10041
10042 const size_t NumFields =
10043 std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
10044
10045 assert(NumFields == (size_t)std::distance(E->capture_init_begin(),((void)0)
10046 E->capture_init_end()) &&((void)0)
10047 "The number of lambda capture initializers should equal the number of "((void)0)
10048 "fields within the closure type")((void)0);
10049
10050 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
10051 // Iterate through all the lambda's closure object's fields and initialize
10052 // them.
10053 auto *CaptureInitIt = E->capture_init_begin();
10054 const LambdaCapture *CaptureIt = ClosureClass->captures_begin();
10055 bool Success = true;
10056 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(ClosureClass);
10057 for (const auto *Field : ClosureClass->fields()) {
10058 assert(CaptureInitIt != E->capture_init_end())((void)0);
10059 // Get the initializer for this field
10060 Expr *const CurFieldInit = *CaptureInitIt++;
10061
10062 // If there is no initializer, either this is a VLA or an error has
10063 // occurred.
10064 if (!CurFieldInit)
10065 return Error(E);
10066
10067 LValue Subobject = This;
10068
10069 if (!HandleLValueMember(Info, E, Subobject, Field, &Layout))
10070 return false;
10071
10072 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
10073 if (!EvaluateInPlace(FieldVal, Info, Subobject, CurFieldInit)) {
10074 if (!Info.keepEvaluatingAfterFailure())
10075 return false;
10076 Success = false;
10077 }
10078 ++CaptureIt;
10079 }
10080 return Success;
10081}
10082
10083static bool EvaluateRecord(const Expr *E, const LValue &This,
10084 APValue &Result, EvalInfo &Info) {
10085 assert(!E->isValueDependent())((void)0);
10086 assert(E->isPRValue() && E->getType()->isRecordType() &&((void)0)
10087 "can't evaluate expression as a record rvalue")((void)0);
10088 return RecordExprEvaluator(Info, This, Result).Visit(E);
10089}
10090
10091//===----------------------------------------------------------------------===//
10092// Temporary Evaluation
10093//
10094// Temporaries are represented in the AST as rvalues, but generally behave like
10095// lvalues. The full-object of which the temporary is a subobject is implicitly
10096// materialized so that a reference can bind to it.
10097//===----------------------------------------------------------------------===//
10098namespace {
10099class TemporaryExprEvaluator
10100 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
10101public:
10102 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
10103 LValueExprEvaluatorBaseTy(Info, Result, false) {}
10104
10105 /// Visit an expression which constructs the value of this temporary.
10106 bool VisitConstructExpr(const Expr *E) {
10107 APValue &Value = Info.CurrentCall->createTemporary(
10108 E, E->getType(), ScopeKind::FullExpression, Result);
10109 return EvaluateInPlace(Value, Info, Result, E);
10110 }
10111
10112 bool VisitCastExpr(const CastExpr *E) {
10113 switch (E->getCastKind()) {
10114 default:
10115 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
10116
10117 case CK_ConstructorConversion:
10118 return VisitConstructExpr(E->getSubExpr());
10119 }
10120 }
10121 bool VisitInitListExpr(const InitListExpr *E) {
10122 return VisitConstructExpr(E);
10123 }
10124 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
10125 return VisitConstructExpr(E);
10126 }
10127 bool VisitCallExpr(const CallExpr *E) {
10128 return VisitConstructExpr(E);
10129 }
10130 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
10131 return VisitConstructExpr(E);
10132 }
10133 bool VisitLambdaExpr(const LambdaExpr *E) {
10134 return VisitConstructExpr(E);
10135 }
10136};
10137} // end anonymous namespace
10138
10139/// Evaluate an expression of record type as a temporary.
10140static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
10141 assert(!E->isValueDependent())((void)0);
10142 assert(E->isPRValue() && E->getType()->isRecordType())((void)0);
10143 return TemporaryExprEvaluator(Info, Result).Visit(E);
10144}
10145
10146//===----------------------------------------------------------------------===//
10147// Vector Evaluation
10148//===----------------------------------------------------------------------===//
10149
10150namespace {
10151 class VectorExprEvaluator
10152 : public ExprEvaluatorBase<VectorExprEvaluator> {
10153 APValue &Result;
10154 public:
10155
10156 VectorExprEvaluator(EvalInfo &info, APValue &Result)
10157 : ExprEvaluatorBaseTy(info), Result(Result) {}
10158
10159 bool Success(ArrayRef<APValue> V, const Expr *E) {
10160 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements())((void)0);
10161 // FIXME: remove this APValue copy.
10162 Result = APValue(V.data(), V.size());
10163 return true;
10164 }
10165 bool Success(const APValue &V, const Expr *E) {
10166 assert(V.isVector())((void)0);
10167 Result = V;
10168 return true;
10169 }
10170 bool ZeroInitialization(const Expr *E);
10171
10172 bool VisitUnaryReal(const UnaryOperator *E)
10173 { return Visit(E->getSubExpr()); }
10174 bool VisitCastExpr(const CastExpr* E);
10175 bool VisitInitListExpr(const InitListExpr *E);
10176 bool VisitUnaryImag(const UnaryOperator *E);
10177 bool VisitBinaryOperator(const BinaryOperator *E);
10178 // FIXME: Missing: unary -, unary ~, conditional operator (for GNU
10179 // conditional select), shufflevector, ExtVectorElementExpr
10180 };
10181} // end anonymous namespace
10182
10183static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
10184 assert(E->isPRValue() && E->getType()->isVectorType() &&((void)0)
10185 "not a vector prvalue")((void)0);
10186 return VectorExprEvaluator(Info, Result).Visit(E);
10187}
10188
10189bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
10190 const VectorType *VTy = E->getType()->castAs<VectorType>();
10191 unsigned NElts = VTy->getNumElements();
10192
10193 const Expr *SE = E->getSubExpr();
10194 QualType SETy = SE->getType();
10195
10196 switch (E->getCastKind()) {
10197 case CK_VectorSplat: {
10198 APValue Val = APValue();
10199 if (SETy->isIntegerType()) {
10200 APSInt IntResult;
10201 if (!EvaluateInteger(SE, IntResult, Info))
10202 return false;
10203 Val = APValue(std::move(IntResult));
10204 } else if (SETy->isRealFloatingType()) {
10205 APFloat FloatResult(0.0);
10206 if (!EvaluateFloat(SE, FloatResult, Info))
10207 return false;
10208 Val = APValue(std::move(FloatResult));
10209 } else {
10210 return Error(E);
10211 }
10212
10213 // Splat and create vector APValue.
10214 SmallVector<APValue, 4> Elts(NElts, Val);
10215 return Success(Elts, E);
10216 }
10217 case CK_BitCast: {
10218 // Evaluate the operand into an APInt we can extract from.
10219 llvm::APInt SValInt;
10220 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
10221 return false;
10222 // Extract the elements
10223 QualType EltTy = VTy->getElementType();
10224 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
10225 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
10226 SmallVector<APValue, 4> Elts;
10227 if (EltTy->isRealFloatingType()) {
10228 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
10229 unsigned FloatEltSize = EltSize;
10230 if (&Sem == &APFloat::x87DoubleExtended())
10231 FloatEltSize = 80;
10232 for (unsigned i = 0; i < NElts; i++) {
10233 llvm::APInt Elt;
10234 if (BigEndian)
10235 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
10236 else
10237 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
10238 Elts.push_back(APValue(APFloat(Sem, Elt)));
10239 }
10240 } else if (EltTy->isIntegerType()) {
10241 for (unsigned i = 0; i < NElts; i++) {
10242 llvm::APInt Elt;
10243 if (BigEndian)
10244 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
10245 else
10246 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
10247 Elts.push_back(APValue(APSInt(Elt, !EltTy->isSignedIntegerType())));
10248 }
10249 } else {
10250 return Error(E);
10251 }
10252 return Success(Elts, E);
10253 }
10254 default:
10255 return ExprEvaluatorBaseTy::VisitCastExpr(E);
10256 }
10257}
10258
10259bool
10260VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
10261 const VectorType *VT = E->getType()->castAs<VectorType>();
10262 unsigned NumInits = E->getNumInits();
10263 unsigned NumElements = VT->getNumElements();
10264
10265 QualType EltTy = VT->getElementType();
10266 SmallVector<APValue, 4> Elements;
10267
10268 // The number of initializers can be less than the number of
10269 // vector elements. For OpenCL, this can be due to nested vector
10270 // initialization. For GCC compatibility, missing trailing elements
10271 // should be initialized with zeroes.
10272 unsigned CountInits = 0, CountElts = 0;
10273 while (CountElts < NumElements) {
10274 // Handle nested vector initialization.
10275 if (CountInits < NumInits
10276 && E->getInit(CountInits)->getType()->isVectorType()) {
10277 APValue v;
10278 if (!EvaluateVector(E->getInit(CountInits), v, Info))
10279 return Error(E);
10280 unsigned vlen = v.getVectorLength();
10281 for (unsigned j = 0; j < vlen; j++)
10282 Elements.push_back(v.getVectorElt(j));
10283 CountElts += vlen;
10284 } else if (EltTy->isIntegerType()) {
10285 llvm::APSInt sInt(32);
10286 if (CountInits < NumInits) {
10287 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
10288 return false;
10289 } else // trailing integer zero.
10290 sInt = Info.Ctx.MakeIntValue(0, EltTy);
10291 Elements.push_back(APValue(sInt));
10292 CountElts++;
10293 } else {
10294 llvm::APFloat f(0.0);
10295 if (CountInits < NumInits) {
10296 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
10297 return false;
10298 } else // trailing float zero.
10299 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
10300 Elements.push_back(APValue(f));
10301 CountElts++;
10302 }
10303 CountInits++;
10304 }
10305 return Success(Elements, E);
10306}
10307
10308bool
10309VectorExprEvaluator::ZeroInitialization(const Expr *E) {
10310 const auto *VT = E->getType()->castAs<VectorType>();
10311 QualType EltTy = VT->getElementType();
10312 APValue ZeroElement;
10313 if (EltTy->isIntegerType())
10314 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
10315 else
10316 ZeroElement =
10317 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
10318
10319 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
10320 return Success(Elements, E);
10321}
10322
10323bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
10324 VisitIgnoredValue(E->getSubExpr());
10325 return ZeroInitialization(E);
10326}
10327
10328bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
10329 BinaryOperatorKind Op = E->getOpcode();
10330 assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp &&((void)0)
10331 "Operation not supported on vector types")((void)0);
10332
10333 if (Op == BO_Comma)
10334 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
10335
10336 Expr *LHS = E->getLHS();
10337 Expr *RHS = E->getRHS();
10338
10339 assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() &&((void)0)
10340 "Must both be vector types")((void)0);
10341 // Checking JUST the types are the same would be fine, except shifts don't
10342 // need to have their types be the same (since you always shift by an int).
10343 assert(LHS->getType()->castAs<VectorType>()->getNumElements() ==((void)0)
10344 E->getType()->castAs<VectorType>()->getNumElements() &&((void)0)
10345 RHS->getType()->castAs<VectorType>()->getNumElements() ==((void)0)
10346 E->getType()->castAs<VectorType>()->getNumElements() &&((void)0)
10347 "All operands must be the same size.")((void)0);
10348
10349 APValue LHSValue;
10350 APValue RHSValue;
10351 bool LHSOK = Evaluate(LHSValue, Info, LHS);
10352 if (!LHSOK && !Info.noteFailure())
10353 return false;
10354 if (!Evaluate(RHSValue, Info, RHS) || !LHSOK)
10355 return false;
10356
10357 if (!handleVectorVectorBinOp(Info, E, Op, LHSValue, RHSValue))
10358 return false;
10359
10360 return Success(LHSValue, E);
10361}
10362
10363//===----------------------------------------------------------------------===//
10364// Array Evaluation
10365//===----------------------------------------------------------------------===//
10366
10367namespace {
10368 class ArrayExprEvaluator
10369 : public ExprEvaluatorBase<ArrayExprEvaluator> {
10370 const LValue &This;
10371 APValue &Result;
10372 public:
10373
10374 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
10375 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
10376
10377 bool Success(const APValue &V, const Expr *E) {
10378 assert(V.isArray() && "expected array")((void)0);
10379 Result = V;
10380 return true;
10381 }
10382
10383 bool ZeroInitialization(const Expr *E) {
10384 const ConstantArrayType *CAT =
10385 Info.Ctx.getAsConstantArrayType(E->getType());
10386 if (!CAT) {
10387 if (E->getType()->isIncompleteArrayType()) {
10388 // We can be asked to zero-initialize a flexible array member; this
10389 // is represented as an ImplicitValueInitExpr of incomplete array
10390 // type. In this case, the array has zero elements.
10391 Result = APValue(APValue::UninitArray(), 0, 0);
10392 return true;
10393 }
10394 // FIXME: We could handle VLAs here.
10395 return Error(E);
10396 }
10397
10398 Result = APValue(APValue::UninitArray(), 0,
10399 CAT->getSize().getZExtValue());
10400 if (!Result.hasArrayFiller())
10401 return true;
10402
10403 // Zero-initialize all elements.
10404 LValue Subobject = This;
10405 Subobject.addArray(Info, E, CAT);
10406 ImplicitValueInitExpr VIE(CAT->getElementType());
10407 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
10408 }
10409
10410 bool VisitCallExpr(const CallExpr *E) {
10411 return handleCallExpr(E, Result, &This);
10412 }
10413 bool VisitInitListExpr(const InitListExpr *E,
10414 QualType AllocType = QualType());
10415 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
10416 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
10417 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
10418 const LValue &Subobject,
10419 APValue *Value, QualType Type);
10420 bool VisitStringLiteral(const StringLiteral *E,
10421 QualType AllocType = QualType()) {
10422 expandStringLiteral(Info, E, Result, AllocType);
10423 return true;
10424 }
10425 };
10426} // end anonymous namespace
10427
10428static bool EvaluateArray(const Expr *E, const LValue &This,
10429 APValue &Result, EvalInfo &Info) {
10430 assert(!E->isValueDependent())((void)0);
10431 assert(E->isPRValue() && E->getType()->isArrayType() &&((void)0)
10432 "not an array prvalue")((void)0);
10433 return ArrayExprEvaluator(Info, This, Result).Visit(E);
10434}
10435
10436static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
10437 APValue &Result, const InitListExpr *ILE,
10438 QualType AllocType) {
10439 assert(!ILE->isValueDependent())((void)0);
10440 assert(ILE->isPRValue() && ILE->getType()->isArrayType() &&((void)0)
10441 "not an array prvalue")((void)0);
10442 return ArrayExprEvaluator(Info, This, Result)
10443 .VisitInitListExpr(ILE, AllocType);
10444}
10445
10446static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
10447 APValue &Result,
10448 const CXXConstructExpr *CCE,
10449 QualType AllocType) {
10450 assert(!CCE->isValueDependent())((void)0);
10451 assert(CCE->isPRValue() && CCE->getType()->isArrayType() &&((void)0)
10452 "not an array prvalue")((void)0);
10453 return ArrayExprEvaluator(Info, This, Result)
10454 .VisitCXXConstructExpr(CCE, This, &Result, AllocType);
10455}
10456
10457// Return true iff the given array filler may depend on the element index.
10458static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) {
10459 // For now, just allow non-class value-initialization and initialization
10460 // lists comprised of them.
10461 if (isa<ImplicitValueInitExpr>(FillerExpr))
10462 return false;
10463 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(FillerExpr)) {
10464 for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) {
10465 if (MaybeElementDependentArrayFiller(ILE->getInit(I)))
10466 return true;
10467 }
10468 return false;
10469 }
10470 return true;
10471}
10472
10473bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E,
10474 QualType AllocType) {
10475 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
10476 AllocType.isNull() ? E->getType() : AllocType);
10477 if (!CAT)
10478 return Error(E);
10479
10480 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
10481 // an appropriately-typed string literal enclosed in braces.
10482 if (E->isStringLiteralInit()) {
10483 auto *SL = dyn_cast<StringLiteral>(E->getInit(0)->IgnoreParens());
10484 // FIXME: Support ObjCEncodeExpr here once we support it in
10485 // ArrayExprEvaluator generally.
10486 if (!SL)
10487 return Error(E);
10488 return VisitStringLiteral(SL, AllocType);
10489 }
10490
10491 bool Success = true;
10492
10493 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&((void)0)
10494 "zero-initialized array shouldn't have any initialized elts")((void)0);
10495 APValue Filler;
10496 if (Result.isArray() && Result.hasArrayFiller())
10497 Filler = Result.getArrayFiller();
10498
10499 unsigned NumEltsToInit = E->getNumInits();
10500 unsigned NumElts = CAT->getSize().getZExtValue();
10501 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
10502
10503 // If the initializer might depend on the array index, run it for each
10504 // array element.
10505 if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(FillerExpr))
10506 NumEltsToInit = NumElts;
10507
10508 LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: "do { } while (false)
10509 << NumEltsToInit << ".\n")do { } while (false);
10510
10511 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
10512
10513 // If the array was previously zero-initialized, preserve the
10514 // zero-initialized values.
10515 if (Filler.hasValue()) {
10516 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
10517 Result.getArrayInitializedElt(I) = Filler;
10518 if (Result.hasArrayFiller())
10519 Result.getArrayFiller() = Filler;
10520 }
10521
10522 LValue Subobject = This;
10523 Subobject.addArray(Info, E, CAT);
10524 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
10525 const Expr *Init =
10526 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
10527 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
10528 Info, Subobject, Init) ||
10529 !HandleLValueArrayAdjustment(Info, Init, Subobject,
10530 CAT->getElementType(), 1)) {
10531 if (!Info.noteFailure())
10532 return false;
10533 Success = false;
10534 }
10535 }
10536
10537 if (!Result.hasArrayFiller())
10538 return Success;
10539
10540 // If we get here, we have a trivial filler, which we can just evaluate
10541 // once and splat over the rest of the array elements.
10542 assert(FillerExpr && "no array filler for incomplete init list")((void)0);
10543 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
10544 FillerExpr) && Success;
10545}
10546
10547bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
10548 LValue CommonLV;
10549 if (E->getCommonExpr() &&
10550 !Evaluate(Info.CurrentCall->createTemporary(
10551 E->getCommonExpr(),
10552 getStorageType(Info.Ctx, E->getCommonExpr()),
10553 ScopeKind::FullExpression, CommonLV),
10554 Info, E->getCommonExpr()->getSourceExpr()))
10555 return false;
10556
10557 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
10558
10559 uint64_t Elements = CAT->getSize().getZExtValue();
10560 Result = APValue(APValue::UninitArray(), Elements, Elements);
10561
10562 LValue Subobject = This;
10563 Subobject.addArray(Info, E, CAT);
10564
10565 bool Success = true;
10566 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
10567 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
10568 Info, Subobject, E->getSubExpr()) ||
10569 !HandleLValueArrayAdjustment(Info, E, Subobject,
10570 CAT->getElementType(), 1)) {
10571 if (!Info.noteFailure())
10572 return false;
10573 Success = false;
10574 }
10575 }
10576
10577 return Success;
10578}
10579
10580bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
10581 return VisitCXXConstructExpr(E, This, &Result, E->getType());
10582}
10583
10584bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
10585 const LValue &Subobject,
10586 APValue *Value,
10587 QualType Type) {
10588 bool HadZeroInit = Value->hasValue();
10589
10590 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
10591 unsigned N = CAT->getSize().getZExtValue();
10592
10593 // Preserve the array filler if we had prior zero-initialization.
10594 APValue Filler =
10595 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
10596 : APValue();
10597
10598 *Value = APValue(APValue::UninitArray(), N, N);
10599
10600 if (HadZeroInit)
10601 for (unsigned I = 0; I != N; ++I)
10602 Value->getArrayInitializedElt(I) = Filler;
10603
10604 // Initialize the elements.
10605 LValue ArrayElt = Subobject;
10606 ArrayElt.addArray(Info, E, CAT);
10607 for (unsigned I = 0; I != N; ++I)
10608 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
10609 CAT->getElementType()) ||
10610 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
10611 CAT->getElementType(), 1))
10612 return false;
10613
10614 return true;
10615 }
10616
10617 if (!Type->isRecordType())
10618 return Error(E);
10619
10620 return RecordExprEvaluator(Info, Subobject, *Value)
10621 .VisitCXXConstructExpr(E, Type);
10622}
10623
10624//===----------------------------------------------------------------------===//
10625// Integer Evaluation
10626//
10627// As a GNU extension, we support casting pointers to sufficiently-wide integer
10628// types and back in constant folding. Integer values are thus represented
10629// either as an integer-valued APValue, or as an lvalue-valued APValue.
10630//===----------------------------------------------------------------------===//
10631
10632namespace {
10633class IntExprEvaluator
10634 : public ExprEvaluatorBase<IntExprEvaluator> {
10635 APValue &Result;
10636public:
10637 IntExprEvaluator(EvalInfo &info, APValue &result)
10638 : ExprEvaluatorBaseTy(info), Result(result) {}
10639
10640 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
10641 assert(E->getType()->isIntegralOrEnumerationType() &&((void)0)
10642 "Invalid evaluation result.")((void)0);
10643 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&((void)0)
10644 "Invalid evaluation result.")((void)0);
10645 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&((void)0)
10646 "Invalid evaluation result.")((void)0);
10647 Result = APValue(SI);
10648 return true;
10649 }
10650 bool Success(const llvm::APSInt &SI, const Expr *E) {
10651 return Success(SI, E, Result);
10652 }
10653
10654 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
10655 assert(E->getType()->isIntegralOrEnumerationType() &&((void)0)
10656 "Invalid evaluation result.")((void)0);
10657 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&((void)0)
10658 "Invalid evaluation result.")((void)0);
10659 Result = APValue(APSInt(I));
10660 Result.getInt().setIsUnsigned(
10661 E->getType()->isUnsignedIntegerOrEnumerationType());
10662 return true;
10663 }
10664 bool Success(const llvm::APInt &I, const Expr *E) {
10665 return Success(I, E, Result);
10666 }
10667
10668 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
10669 assert(E->getType()->isIntegralOrEnumerationType() &&((void)0)
10670 "Invalid evaluation result.")((void)0);
10671 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
10672 return true;
10673 }
10674 bool Success(uint64_t Value, const Expr *E) {
10675 return Success(Value, E, Result);
10676 }
10677
10678 bool Success(CharUnits Size, const Expr *E) {
10679 return Success(Size.getQuantity(), E);
10680 }
10681
10682 bool Success(const APValue &V, const Expr *E) {
10683 if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) {
10684 Result = V;
10685 return true;
10686 }
10687 return Success(V.getInt(), E);
10688 }
10689
10690 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
10691
10692 //===--------------------------------------------------------------------===//
10693 // Visitor Methods
10694 //===--------------------------------------------------------------------===//
10695
10696 bool VisitIntegerLiteral(const IntegerLiteral *E) {
10697 return Success(E->getValue(), E);
10698 }
10699 bool VisitCharacterLiteral(const CharacterLiteral *E) {
10700 return Success(E->getValue(), E);
10701 }
10702
10703 bool CheckReferencedDecl(const Expr *E, const Decl *D);
10704 bool VisitDeclRefExpr(const DeclRefExpr *E) {
10705 if (CheckReferencedDecl(E, E->getDecl()))
10706 return true;
10707
10708 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
10709 }
10710 bool VisitMemberExpr(const MemberExpr *E) {
10711 if (CheckReferencedDecl(E, E->getMemberDecl())) {
10712 VisitIgnoredBaseExpression(E->getBase());
10713 return true;
10714 }
10715
10716 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
10717 }
10718
10719 bool VisitCallExpr(const CallExpr *E);
10720 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
10721 bool VisitBinaryOperator(const BinaryOperator *E);
10722 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
10723 bool VisitUnaryOperator(const UnaryOperator *E);
10724
10725 bool VisitCastExpr(const CastExpr* E);
10726 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
10727
10728 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
10729 return Success(E->getValue(), E);
10730 }
10731
10732 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
10733 return Success(E->getValue(), E);
10734 }
10735
10736 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
10737 if (Info.ArrayInitIndex == uint64_t(-1)) {
10738 // We were asked to evaluate this subexpression independent of the
10739 // enclosing ArrayInitLoopExpr. We can't do that.
10740 Info.FFDiag(E);
10741 return false;
10742 }
10743 return Success(Info.ArrayInitIndex, E);
10744 }
10745
10746 // Note, GNU defines __null as an integer, not a pointer.
10747 bool VisitGNUNullExpr(const GNUNullExpr *E) {
10748 return ZeroInitialization(E);
10749 }
10750
10751 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
10752 return Success(E->getValue(), E);
10753 }
10754
10755 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
10756 return Success(E->getValue(), E);
10757 }
10758
10759 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
10760 return Success(E->getValue(), E);
10761 }
10762
10763 bool VisitUnaryReal(const UnaryOperator *E);
10764 bool VisitUnaryImag(const UnaryOperator *E);
10765
10766 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
10767 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
10768 bool VisitSourceLocExpr(const SourceLocExpr *E);
10769 bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
10770 bool VisitRequiresExpr(const RequiresExpr *E);
10771 // FIXME: Missing: array subscript of vector, member of vector
10772};
10773
10774class FixedPointExprEvaluator
10775 : public ExprEvaluatorBase<FixedPointExprEvaluator> {
10776 APValue &Result;
10777
10778 public:
10779 FixedPointExprEvaluator(EvalInfo &info, APValue &result)
10780 : ExprEvaluatorBaseTy(info), Result(result) {}
10781
10782 bool Success(const llvm::APInt &I, const Expr *E) {
10783 return Success(
10784 APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E);
10785 }
10786
10787 bool Success(uint64_t Value, const Expr *E) {
10788 return Success(
10789 APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E);
10790 }
10791
10792 bool Success(const APValue &V, const Expr *E) {
10793 return Success(V.getFixedPoint(), E);
10794 }
10795
10796 bool Success(const APFixedPoint &V, const Expr *E) {
10797 assert(E->getType()->isFixedPointType() && "Invalid evaluation result.")((void)0);
10798 assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&((void)0)
10799 "Invalid evaluation result.")((void)0);
10800 Result = APValue(V);
10801 return true;
10802 }
10803
10804 //===--------------------------------------------------------------------===//
10805 // Visitor Methods
10806 //===--------------------------------------------------------------------===//
10807
10808 bool VisitFixedPointLiteral(const FixedPointLiteral *E) {
10809 return Success(E->getValue(), E);
10810 }
10811
10812 bool VisitCastExpr(const CastExpr *E);
10813 bool VisitUnaryOperator(const UnaryOperator *E);
10814 bool VisitBinaryOperator(const BinaryOperator *E);
10815};
10816} // end anonymous namespace
10817
10818/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
10819/// produce either the integer value or a pointer.
10820///
10821/// GCC has a heinous extension which folds casts between pointer types and
10822/// pointer-sized integral types. We support this by allowing the evaluation of
10823/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
10824/// Some simple arithmetic on such values is supported (they are treated much
10825/// like char*).
10826static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
10827 EvalInfo &Info) {
10828 assert(!E->isValueDependent())((void)0);
10829 assert(E->isPRValue() && E->getType()->isIntegralOrEnumerationType())((void)0);
10830 return IntExprEvaluator(Info, Result).Visit(E);
10831}
10832
10833static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
10834 assert(!E->isValueDependent())((void)0);
10835 APValue Val;
10836 if (!EvaluateIntegerOrLValue(E, Val, Info))
10837 return false;
10838 if (!Val.isInt()) {
10839 // FIXME: It would be better to produce the diagnostic for casting
10840 // a pointer to an integer.
10841 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
10842 return false;
10843 }
10844 Result = Val.getInt();
10845 return true;
10846}
10847
10848bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) {
10849 APValue Evaluated = E->EvaluateInContext(
10850 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
10851 return Success(Evaluated, E);
10852}
10853
10854static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
10855 EvalInfo &Info) {
10856 assert(!E->isValueDependent())((void)0);
10857 if (E->getType()->isFixedPointType()) {
10858 APValue Val;
10859 if (!FixedPointExprEvaluator(Info, Val).Visit(E))
10860 return false;
10861 if (!Val.isFixedPoint())
10862 return false;
10863
10864 Result = Val.getFixedPoint();
10865 return true;
10866 }
10867 return false;
10868}
10869
10870static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
10871 EvalInfo &Info) {
10872 assert(!E->isValueDependent())((void)0);
10873 if (E->getType()->isIntegerType()) {
10874 auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType());
10875 APSInt Val;
10876 if (!EvaluateInteger(E, Val, Info))
10877 return false;
10878 Result = APFixedPoint(Val, FXSema);
10879 return true;
10880 } else if (E->getType()->isFixedPointType()) {
10881 return EvaluateFixedPoint(E, Result, Info);
10882 }
10883 return false;
10884}
10885
10886/// Check whether the given declaration can be directly converted to an integral
10887/// rvalue. If not, no diagnostic is produced; there are other things we can
10888/// try.
10889bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
10890 // Enums are integer constant exprs.
10891 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
10892 // Check for signedness/width mismatches between E type and ECD value.
10893 bool SameSign = (ECD->getInitVal().isSigned()
10894 == E->getType()->isSignedIntegerOrEnumerationType());
10895 bool SameWidth = (ECD->getInitVal().getBitWidth()
10896 == Info.Ctx.getIntWidth(E->getType()));
10897 if (SameSign && SameWidth)
10898 return Success(ECD->getInitVal(), E);
10899 else {
10900 // Get rid of mismatch (otherwise Success assertions will fail)
10901 // by computing a new value matching the type of E.
10902 llvm::APSInt Val = ECD->getInitVal();
10903 if (!SameSign)
10904 Val.setIsSigned(!ECD->getInitVal().isSigned());
10905 if (!SameWidth)
10906 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
10907 return Success(Val, E);
10908 }
10909 }
10910 return false;
10911}
10912
10913/// Values returned by __builtin_classify_type, chosen to match the values
10914/// produced by GCC's builtin.
10915enum class GCCTypeClass {
10916 None = -1,
10917 Void = 0,
10918 Integer = 1,
10919 // GCC reserves 2 for character types, but instead classifies them as
10920 // integers.
10921 Enum = 3,
10922 Bool = 4,
10923 Pointer = 5,
10924 // GCC reserves 6 for references, but appears to never use it (because
10925 // expressions never have reference type, presumably).
10926 PointerToDataMember = 7,
10927 RealFloat = 8,
10928 Complex = 9,
10929 // GCC reserves 10 for functions, but does not use it since GCC version 6 due
10930 // to decay to pointer. (Prior to version 6 it was only used in C++ mode).
10931 // GCC claims to reserve 11 for pointers to member functions, but *actually*
10932 // uses 12 for that purpose, same as for a class or struct. Maybe it
10933 // internally implements a pointer to member as a struct? Who knows.
10934 PointerToMemberFunction = 12, // Not a bug, see above.
10935 ClassOrStruct = 12,
10936 Union = 13,
10937 // GCC reserves 14 for arrays, but does not use it since GCC version 6 due to
10938 // decay to pointer. (Prior to version 6 it was only used in C++ mode).
10939 // GCC reserves 15 for strings, but actually uses 5 (pointer) for string
10940 // literals.
10941};
10942
10943/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
10944/// as GCC.
10945static GCCTypeClass
10946EvaluateBuiltinClassifyType(QualType T, const LangOptions &LangOpts) {
10947 assert(!T->isDependentType() && "unexpected dependent type")((void)0);
10948
10949 QualType CanTy = T.getCanonicalType();
10950 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
10951
10952 switch (CanTy->getTypeClass()) {
10953#define TYPE(ID, BASE)
10954#define DEPENDENT_TYPE(ID, BASE) case Type::ID:
10955#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
10956#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
10957#include "clang/AST/TypeNodes.inc"
10958 case Type::Auto:
10959 case Type::DeducedTemplateSpecialization:
10960 llvm_unreachable("unexpected non-canonical or dependent type")__builtin_unreachable();
10961
10962 case Type::Builtin:
10963 switch (BT->getKind()) {
10964#define BUILTIN_TYPE(ID, SINGLETON_ID)
10965#define SIGNED_TYPE(ID, SINGLETON_ID) \
10966 case BuiltinType::ID: return GCCTypeClass::Integer;
10967#define FLOATING_TYPE(ID, SINGLETON_ID) \
10968 case BuiltinType::ID: return GCCTypeClass::RealFloat;
10969#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \
10970 case BuiltinType::ID: break;
10971#include "clang/AST/BuiltinTypes.def"
10972 case BuiltinType::Void:
10973 return GCCTypeClass::Void;
10974
10975 case BuiltinType::Bool:
10976 return GCCTypeClass::Bool;
10977
10978 case BuiltinType::Char_U:
10979 case BuiltinType::UChar:
10980 case BuiltinType::WChar_U:
10981 case BuiltinType::Char8:
10982 case BuiltinType::Char16:
10983 case BuiltinType::Char32:
10984 case BuiltinType::UShort:
10985 case BuiltinType::UInt:
10986 case BuiltinType::ULong:
10987 case BuiltinType::ULongLong:
10988 case BuiltinType::UInt128:
10989 return GCCTypeClass::Integer;
10990
10991 case BuiltinType::UShortAccum:
10992 case BuiltinType::UAccum:
10993 case BuiltinType::ULongAccum:
10994 case BuiltinType::UShortFract:
10995 case BuiltinType::UFract:
10996 case BuiltinType::ULongFract:
10997 case BuiltinType::SatUShortAccum:
10998 case BuiltinType::SatUAccum:
10999 case BuiltinType::SatULongAccum:
11000 case BuiltinType::SatUShortFract:
11001 case BuiltinType::SatUFract:
11002 case BuiltinType::SatULongFract:
11003 return GCCTypeClass::None;
11004
11005 case BuiltinType::NullPtr:
11006
11007 case BuiltinType::ObjCId:
11008 case BuiltinType::ObjCClass:
11009 case BuiltinType::ObjCSel:
11010#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
11011 case BuiltinType::Id:
11012#include "clang/Basic/OpenCLImageTypes.def"
11013#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
11014 case BuiltinType::Id:
11015#include "clang/Basic/OpenCLExtensionTypes.def"
11016 case BuiltinType::OCLSampler:
11017 case BuiltinType::OCLEvent:
11018 case BuiltinType::OCLClkEvent:
11019 case BuiltinType::OCLQueue:
11020 case BuiltinType::OCLReserveID:
11021#define SVE_TYPE(Name, Id, SingletonId) \
11022 case BuiltinType::Id:
11023#include "clang/Basic/AArch64SVEACLETypes.def"
11024#define PPC_VECTOR_TYPE(Name, Id, Size) \
11025 case BuiltinType::Id:
11026#include "clang/Basic/PPCTypes.def"
11027#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
11028#include "clang/Basic/RISCVVTypes.def"
11029 return GCCTypeClass::None;
11030
11031 case BuiltinType::Dependent:
11032 llvm_unreachable("unexpected dependent type")__builtin_unreachable();
11033 };
11034 llvm_unreachable("unexpected placeholder type")__builtin_unreachable();
11035
11036 case Type::Enum:
11037 return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer;
11038
11039 case Type::Pointer:
11040 case Type::ConstantArray:
11041 case Type::VariableArray:
11042 case Type::IncompleteArray:
11043 case Type::FunctionNoProto:
11044 case Type::FunctionProto:
11045 return GCCTypeClass::Pointer;
11046
11047 case Type::MemberPointer:
11048 return CanTy->isMemberDataPointerType()
11049 ? GCCTypeClass::PointerToDataMember
11050 : GCCTypeClass::PointerToMemberFunction;
11051
11052 case Type::Complex:
11053 return GCCTypeClass::Complex;
11054
11055 case Type::Record:
11056 return CanTy->isUnionType() ? GCCTypeClass::Union
11057 : GCCTypeClass::ClassOrStruct;
11058
11059 case Type::Atomic:
11060 // GCC classifies _Atomic T the same as T.
11061 return EvaluateBuiltinClassifyType(
11062 CanTy->castAs<AtomicType>()->getValueType(), LangOpts);
11063
11064 case Type::BlockPointer:
11065 case Type::Vector:
11066 case Type::ExtVector:
11067 case Type::ConstantMatrix:
11068 case Type::ObjCObject:
11069 case Type::ObjCInterface:
11070 case Type::ObjCObjectPointer:
11071 case Type::Pipe:
11072 case Type::ExtInt:
11073 // GCC classifies vectors as None. We follow its lead and classify all
11074 // other types that don't fit into the regular classification the same way.
11075 return GCCTypeClass::None;
11076
11077 case Type::LValueReference:
11078 case Type::RValueReference:
11079 llvm_unreachable("invalid type for expression")__builtin_unreachable();
11080 }
11081
11082 llvm_unreachable("unexpected type class")__builtin_unreachable();
11083}
11084
11085/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
11086/// as GCC.
11087static GCCTypeClass
11088EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) {
11089 // If no argument was supplied, default to None. This isn't
11090 // ideal, however it is what gcc does.
11091 if (E->getNumArgs() == 0)
11092 return GCCTypeClass::None;
11093
11094 // FIXME: Bizarrely, GCC treats a call with more than one argument as not
11095 // being an ICE, but still folds it to a constant using the type of the first
11096 // argument.
11097 return EvaluateBuiltinClassifyType(E->getArg(0)->getType(), LangOpts);
11098}
11099
11100/// EvaluateBuiltinConstantPForLValue - Determine the result of
11101/// __builtin_constant_p when applied to the given pointer.
11102///
11103/// A pointer is only "constant" if it is null (or a pointer cast to integer)
11104/// or it points to the first character of a string literal.
11105static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
11106 APValue::LValueBase Base = LV.getLValueBase();
11107 if (Base.isNull()) {
11108 // A null base is acceptable.
11109 return true;
11110 } else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
11111 if (!isa<StringLiteral>(E))
11112 return false;
11113 return LV.getLValueOffset().isZero();
11114 } else if (Base.is<TypeInfoLValue>()) {
11115 // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
11116 // evaluate to true.
11117 return true;
11118 } else {
11119 // Any other base is not constant enough for GCC.
11120 return false;
11121 }
11122}
11123
11124/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
11125/// GCC as we can manage.
11126static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
11127 // This evaluation is not permitted to have side-effects, so evaluate it in
11128 // a speculative evaluation context.
11129 SpeculativeEvaluationRAII SpeculativeEval(Info);
11130
11131 // Constant-folding is always enabled for the operand of __builtin_constant_p
11132 // (even when the enclosing evaluation context otherwise requires a strict
11133 // language-specific constant expression).
11134 FoldConstant Fold(Info, true);
11135
11136 QualType ArgType = Arg->getType();
11137
11138 // __builtin_constant_p always has one operand. The rules which gcc follows
11139 // are not precisely documented, but are as follows:
11140 //
11141 // - If the operand is of integral, floating, complex or enumeration type,
11142 // and can be folded to a known value of that type, it returns 1.
11143 // - If the operand can be folded to a pointer to the first character
11144 // of a string literal (or such a pointer cast to an integral type)
11145 // or to a null pointer or an integer cast to a pointer, it returns 1.
11146 //
11147 // Otherwise, it returns 0.
11148 //
11149 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
11150 // its support for this did not work prior to GCC 9 and is not yet well
11151 // understood.
11152 if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
11153 ArgType->isAnyComplexType() || ArgType->isPointerType() ||
11154 ArgType->isNullPtrType()) {
11155 APValue V;
11156 if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) {
11157 Fold.keepDiagnostics();
11158 return false;
11159 }
11160
11161 // For a pointer (possibly cast to integer), there are special rules.
11162 if (V.getKind() == APValue::LValue)
11163 return EvaluateBuiltinConstantPForLValue(V);
11164
11165 // Otherwise, any constant value is good enough.
11166 return V.hasValue();
11167 }
11168
11169 // Anything else isn't considered to be sufficiently constant.
11170 return false;
11171}
11172
11173/// Retrieves the "underlying object type" of the given expression,
11174/// as used by __builtin_object_size.
11175static QualType getObjectType(APValue::LValueBase B) {
11176 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
11177 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
11178 return VD->getType();
11179 } else if (const Expr *E = B.dyn_cast<const Expr*>()) {
11180 if (isa<CompoundLiteralExpr>(E))
11181 return E->getType();
11182 } else if (B.is<TypeInfoLValue>()) {
11183 return B.getTypeInfoType();
11184 } else if (B.is<DynamicAllocLValue>()) {
11185 return B.getDynamicAllocType();
11186 }
11187
11188 return QualType();
11189}
11190
11191/// A more selective version of E->IgnoreParenCasts for
11192/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
11193/// to change the type of E.
11194/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
11195///
11196/// Always returns an RValue with a pointer representation.
11197static const Expr *ignorePointerCastsAndParens(const Expr *E) {
11198 assert(E->isPRValue() && E->getType()->hasPointerRepresentation())((void)0);
11199
11200 auto *NoParens = E->IgnoreParens();
11201 auto *Cast = dyn_cast<CastExpr>(NoParens);
11202 if (Cast == nullptr)
11203 return NoParens;
11204
11205 // We only conservatively allow a few kinds of casts, because this code is
11206 // inherently a simple solution that seeks to support the common case.
11207 auto CastKind = Cast->getCastKind();
11208 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
11209 CastKind != CK_AddressSpaceConversion)
11210 return NoParens;
11211
11212 auto *SubExpr = Cast->getSubExpr();
11213 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isPRValue())
11214 return NoParens;
11215 return ignorePointerCastsAndParens(SubExpr);
11216}
11217
11218/// Checks to see if the given LValue's Designator is at the end of the LValue's
11219/// record layout. e.g.
11220/// struct { struct { int a, b; } fst, snd; } obj;
11221/// obj.fst // no
11222/// obj.snd // yes
11223/// obj.fst.a // no
11224/// obj.fst.b // no
11225/// obj.snd.a // no
11226/// obj.snd.b // yes
11227///
11228/// Please note: this function is specialized for how __builtin_object_size
11229/// views "objects".
11230///
11231/// If this encounters an invalid RecordDecl or otherwise cannot determine the
11232/// correct result, it will always return true.
11233static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
11234 assert(!LVal.Designator.Invalid)((void)0);
11235
11236 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
11237 const RecordDecl *Parent = FD->getParent();
11238 Invalid = Parent->isInvalidDecl();
11239 if (Invalid || Parent->isUnion())
11240 return true;
11241 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
11242 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
11243 };
11244
11245 auto &Base = LVal.getLValueBase();
11246 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
11247 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
11248 bool Invalid;
11249 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
11250 return Invalid;
11251 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
11252 for (auto *FD : IFD->chain()) {
11253 bool Invalid;
11254 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
11255 return Invalid;
11256 }
11257 }
11258 }
11259
11260 unsigned I = 0;
11261 QualType BaseType = getType(Base);
11262 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
11263 // If we don't know the array bound, conservatively assume we're looking at
11264 // the final array element.
11265 ++I;
11266 if (BaseType->isIncompleteArrayType())
11267 BaseType = Ctx.getAsArrayType(BaseType)->getElementType();
11268 else
11269 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
11270 }
11271
11272 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
11273 const auto &Entry = LVal.Designator.Entries[I];
11274 if (BaseType->isArrayType()) {
11275 // Because __builtin_object_size treats arrays as objects, we can ignore
11276 // the index iff this is the last array in the Designator.
11277 if (I + 1 == E)
11278 return true;
11279 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
11280 uint64_t Index = Entry.getAsArrayIndex();
11281 if (Index + 1 != CAT->getSize())
11282 return false;
11283 BaseType = CAT->getElementType();
11284 } else if (BaseType->isAnyComplexType()) {
11285 const auto *CT = BaseType->castAs<ComplexType>();
11286 uint64_t Index = Entry.getAsArrayIndex();
11287 if (Index != 1)
11288 return false;
11289 BaseType = CT->getElementType();
11290 } else if (auto *FD = getAsField(Entry)) {
11291 bool Invalid;
11292 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
11293 return Invalid;
11294 BaseType = FD->getType();
11295 } else {
11296 assert(getAsBaseClass(Entry) && "Expecting cast to a base class")((void)0);
11297 return false;
11298 }
11299 }
11300 return true;
11301}
11302
11303/// Tests to see if the LValue has a user-specified designator (that isn't
11304/// necessarily valid). Note that this always returns 'true' if the LValue has
11305/// an unsized array as its first designator entry, because there's currently no
11306/// way to tell if the user typed *foo or foo[0].
11307static bool refersToCompleteObject(const LValue &LVal) {
11308 if (LVal.Designator.Invalid)
11309 return false;
11310
11311 if (!LVal.Designator.Entries.empty())
11312 return LVal.Designator.isMostDerivedAnUnsizedArray();
11313
11314 if (!LVal.InvalidBase)
11315 return true;
11316
11317 // If `E` is a MemberExpr, then the first part of the designator is hiding in
11318 // the LValueBase.
11319 const auto *E = LVal.Base.dyn_cast<const Expr *>();
11320 return !E || !isa<MemberExpr>(E);
11321}
11322
11323/// Attempts to detect a user writing into a piece of memory that's impossible
11324/// to figure out the size of by just using types.
11325static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
11326 const SubobjectDesignator &Designator = LVal.Designator;
11327 // Notes:
11328 // - Users can only write off of the end when we have an invalid base. Invalid
11329 // bases imply we don't know where the memory came from.
11330 // - We used to be a bit more aggressive here; we'd only be conservative if
11331 // the array at the end was flexible, or if it had 0 or 1 elements. This
11332 // broke some common standard library extensions (PR30346), but was
11333 // otherwise seemingly fine. It may be useful to reintroduce this behavior
11334 // with some sort of list. OTOH, it seems that GCC is always
11335 // conservative with the last element in structs (if it's an array), so our
11336 // current behavior is more compatible than an explicit list approach would
11337 // be.
11338 return LVal.InvalidBase &&
11339 Designator.Entries.size() == Designator.MostDerivedPathLength &&
11340 Designator.MostDerivedIsArrayElement &&
11341 isDesignatorAtObjectEnd(Ctx, LVal);
11342}
11343
11344/// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
11345/// Fails if the conversion would cause loss of precision.
11346static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
11347 CharUnits &Result) {
11348 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
11349 if (Int.ugt(CharUnitsMax))
11350 return false;
11351 Result = CharUnits::fromQuantity(Int.getZExtValue());
11352 return true;
11353}
11354
11355/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
11356/// determine how many bytes exist from the beginning of the object to either
11357/// the end of the current subobject, or the end of the object itself, depending
11358/// on what the LValue looks like + the value of Type.
11359///
11360/// If this returns false, the value of Result is undefined.
11361static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
11362 unsigned Type, const LValue &LVal,
11363 CharUnits &EndOffset) {
11364 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
11365
11366 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
11367 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
11368 return false;
11369 return HandleSizeof(Info, ExprLoc, Ty, Result);
11370 };
11371
11372 // We want to evaluate the size of the entire object. This is a valid fallback
11373 // for when Type=1 and the designator is invalid, because we're asked for an
11374 // upper-bound.
11375 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
11376 // Type=3 wants a lower bound, so we can't fall back to this.
11377 if (Type == 3 && !DetermineForCompleteObject)
11378 return false;
11379
11380 llvm::APInt APEndOffset;
11381 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
11382 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
11383 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
11384
11385 if (LVal.InvalidBase)
11386 return false;
11387
11388 QualType BaseTy = getObjectType(LVal.getLValueBase());
11389 return CheckedHandleSizeof(BaseTy, EndOffset);
11390 }
11391
11392 // We want to evaluate the size of a subobject.
11393 const SubobjectDesignator &Designator = LVal.Designator;
11394
11395 // The following is a moderately common idiom in C:
11396 //
11397 // struct Foo { int a; char c[1]; };
11398 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
11399 // strcpy(&F->c[0], Bar);
11400 //
11401 // In order to not break too much legacy code, we need to support it.
11402 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
11403 // If we can resolve this to an alloc_size call, we can hand that back,
11404 // because we know for certain how many bytes there are to write to.
11405 llvm::APInt APEndOffset;
11406 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
11407 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
11408 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
11409
11410 // If we cannot determine the size of the initial allocation, then we can't
11411 // given an accurate upper-bound. However, we are still able to give
11412 // conservative lower-bounds for Type=3.
11413 if (Type == 1)
11414 return false;
11415 }
11416
11417 CharUnits BytesPerElem;
11418 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
11419 return false;
11420
11421 // According to the GCC documentation, we want the size of the subobject
11422 // denoted by the pointer. But that's not quite right -- what we actually
11423 // want is the size of the immediately-enclosing array, if there is one.
11424 int64_t ElemsRemaining;
11425 if (Designator.MostDerivedIsArrayElement &&
11426 Designator.Entries.size() == Designator.MostDerivedPathLength) {
11427 uint64_t ArraySize = Designator.getMostDerivedArraySize();
11428 uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex();
11429 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
11430 } else {
11431 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
11432 }
11433
11434 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
11435 return true;
11436}
11437
11438/// Tries to evaluate the __builtin_object_size for @p E. If successful,
11439/// returns true and stores the result in @p Size.
11440///
11441/// If @p WasError is non-null, this will report whether the failure to evaluate
11442/// is to be treated as an Error in IntExprEvaluator.
11443static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
11444 EvalInfo &Info, uint64_t &Size) {
11445 // Determine the denoted object.
11446 LValue LVal;
11447 {
11448 // The operand of __builtin_object_size is never evaluated for side-effects.
11449 // If there are any, but we can determine the pointed-to object anyway, then
11450 // ignore the side-effects.
11451 SpeculativeEvaluationRAII SpeculativeEval(Info);
11452 IgnoreSideEffectsRAII Fold(Info);
11453
11454 if (E->isGLValue()) {
11455 // It's possible for us to be given GLValues if we're called via
11456 // Expr::tryEvaluateObjectSize.
11457 APValue RVal;
11458 if (!EvaluateAsRValue(Info, E, RVal))
11459 return false;
11460 LVal.setFrom(Info.Ctx, RVal);
11461 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
11462 /*InvalidBaseOK=*/true))
11463 return false;
11464 }
11465
11466 // If we point to before the start of the object, there are no accessible
11467 // bytes.
11468 if (LVal.getLValueOffset().isNegative()) {
11469 Size = 0;
11470 return true;
11471 }
11472
11473 CharUnits EndOffset;
11474 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
11475 return false;
11476
11477 // If we've fallen outside of the end offset, just pretend there's nothing to
11478 // write to/read from.
11479 if (EndOffset <= LVal.getLValueOffset())
11480 Size = 0;
11481 else
11482 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
11483 return true;
11484}
11485
11486bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
11487 if (unsigned BuiltinOp = E->getBuiltinCallee())
11488 return VisitBuiltinCallExpr(E, BuiltinOp);
11489
11490 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11491}
11492
11493static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info,
11494 APValue &Val, APSInt &Alignment) {
11495 QualType SrcTy = E->getArg(0)->getType();
11496 if (!getAlignmentArgument(E->getArg(1), SrcTy, Info, Alignment))
11497 return false;
11498 // Even though we are evaluating integer expressions we could get a pointer
11499 // argument for the __builtin_is_aligned() case.
11500 if (SrcTy->isPointerType()) {
11501 LValue Ptr;
11502 if (!EvaluatePointer(E->getArg(0), Ptr, Info))
11503 return false;
11504 Ptr.moveInto(Val);
11505 } else if (!SrcTy->isIntegralOrEnumerationType()) {
11506 Info.FFDiag(E->getArg(0));
11507 return false;
11508 } else {
11509 APSInt SrcInt;
11510 if (!EvaluateInteger(E->getArg(0), SrcInt, Info))
11511 return false;
11512 assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() &&((void)0)
11513 "Bit widths must be the same")((void)0);
11514 Val = APValue(SrcInt);
11515 }
11516 assert(Val.hasValue())((void)0);
11517 return true;
11518}
11519
11520bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
11521 unsigned BuiltinOp) {
11522 switch (BuiltinOp) {
11523 default:
11524 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11525
11526 case Builtin::BI__builtin_dynamic_object_size:
11527 case Builtin::BI__builtin_object_size: {
11528 // The type was checked when we built the expression.
11529 unsigned Type =
11530 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
11531 assert(Type <= 3 && "unexpected type")((void)0);
11532
11533 uint64_t Size;
11534 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
11535 return Success(Size, E);
11536
11537 if (E->getArg(0)->HasSideEffects(Info.Ctx))
11538 return Success((Type & 2) ? 0 : -1, E);
11539
11540 // Expression had no side effects, but we couldn't statically determine the
11541 // size of the referenced object.
11542 switch (Info.EvalMode) {
11543 case EvalInfo::EM_ConstantExpression:
11544 case EvalInfo::EM_ConstantFold:
11545 case EvalInfo::EM_IgnoreSideEffects:
11546 // Leave it to IR generation.
11547 return Error(E);
11548 case EvalInfo::EM_ConstantExpressionUnevaluated:
11549 // Reduce it to a constant now.
11550 return Success((Type & 2) ? 0 : -1, E);
11551 }
11552
11553 llvm_unreachable("unexpected EvalMode")__builtin_unreachable();
11554 }
11555
11556 case Builtin::BI__builtin_os_log_format_buffer_size: {
11557 analyze_os_log::OSLogBufferLayout Layout;
11558 analyze_os_log::computeOSLogBufferLayout(Info.Ctx, E, Layout);
11559 return Success(Layout.size().getQuantity(), E);
11560 }
11561
11562 case Builtin::BI__builtin_is_aligned: {
11563 APValue Src;
11564 APSInt Alignment;
11565 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11566 return false;
11567 if (Src.isLValue()) {
11568 // If we evaluated a pointer, check the minimum known alignment.
11569 LValue Ptr;
11570 Ptr.setFrom(Info.Ctx, Src);
11571 CharUnits BaseAlignment = getBaseAlignment(Info, Ptr);
11572 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Ptr.Offset);
11573 // We can return true if the known alignment at the computed offset is
11574 // greater than the requested alignment.
11575 assert(PtrAlign.isPowerOfTwo())((void)0);
11576 assert(Alignment.isPowerOf2())((void)0);
11577 if (PtrAlign.getQuantity() >= Alignment)
11578 return Success(1, E);
11579 // If the alignment is not known to be sufficient, some cases could still
11580 // be aligned at run time. However, if the requested alignment is less or
11581 // equal to the base alignment and the offset is not aligned, we know that
11582 // the run-time value can never be aligned.
11583 if (BaseAlignment.getQuantity() >= Alignment &&
11584 PtrAlign.getQuantity() < Alignment)
11585 return Success(0, E);
11586 // Otherwise we can't infer whether the value is sufficiently aligned.
11587 // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N)
11588 // in cases where we can't fully evaluate the pointer.
11589 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute)
11590 << Alignment;
11591 return false;
11592 }
11593 assert(Src.isInt())((void)0);
11594 return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E);
11595 }
11596 case Builtin::BI__builtin_align_up: {
11597 APValue Src;
11598 APSInt Alignment;
11599 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11600 return false;
11601 if (!Src.isInt())
11602 return Error(E);
11603 APSInt AlignedVal =
11604 APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1),
11605 Src.getInt().isUnsigned());
11606 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth())((void)0);
11607 return Success(AlignedVal, E);
11608 }
11609 case Builtin::BI__builtin_align_down: {
11610 APValue Src;
11611 APSInt Alignment;
11612 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11613 return false;
11614 if (!Src.isInt())
11615 return Error(E);
11616 APSInt AlignedVal =
11617 APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned());
11618 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth())((void)0);
11619 return Success(AlignedVal, E);
11620 }
11621
11622 case Builtin::BI__builtin_bitreverse8:
11623 case Builtin::BI__builtin_bitreverse16:
11624 case Builtin::BI__builtin_bitreverse32:
11625 case Builtin::BI__builtin_bitreverse64: {
11626 APSInt Val;
11627 if (!EvaluateInteger(E->getArg(0), Val, Info))
11628 return false;
11629
11630 return Success(Val.reverseBits(), E);
11631 }
11632
11633 case Builtin::BI__builtin_bswap16:
11634 case Builtin::BI__builtin_bswap32:
11635 case Builtin::BI__builtin_bswap64: {
11636 APSInt Val;
11637 if (!EvaluateInteger(E->getArg(0), Val, Info))
11638 return false;
11639
11640 return Success(Val.byteSwap(), E);
11641 }
11642
11643 case Builtin::BI__builtin_classify_type:
11644 return Success((int)EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
11645
11646 case Builtin::BI__builtin_clrsb:
11647 case Builtin::BI__builtin_clrsbl:
11648 case Builtin::BI__builtin_clrsbll: {
11649 APSInt Val;
11650 if (!EvaluateInteger(E->getArg(0), Val, Info))
11651 return false;
11652
11653 return Success(Val.getBitWidth() - Val.getMinSignedBits(), E);
11654 }
11655
11656 case Builtin::BI__builtin_clz:
11657 case Builtin::BI__builtin_clzl:
11658 case Builtin::BI__builtin_clzll:
11659 case Builtin::BI__builtin_clzs: {
11660 APSInt Val;
11661 if (!EvaluateInteger(E->getArg(0), Val, Info))
11662 return false;
11663 if (!Val)
11664 return Error(E);
11665
11666 return Success(Val.countLeadingZeros(), E);
11667 }
11668
11669 case Builtin::BI__builtin_constant_p: {
11670 const Expr *Arg = E->getArg(0);
11671 if (EvaluateBuiltinConstantP(Info, Arg))
11672 return Success(true, E);
11673 if (Info.InConstantContext || Arg->HasSideEffects(Info.Ctx)) {
11674 // Outside a constant context, eagerly evaluate to false in the presence
11675 // of side-effects in order to avoid -Wunsequenced false-positives in
11676 // a branch on __builtin_constant_p(expr).
11677 return Success(false, E);
11678 }
11679 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
11680 return false;
11681 }
11682
11683 case Builtin::BI__builtin_is_constant_evaluated: {
11684 const auto *Callee = Info.CurrentCall->getCallee();
11685 if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression &&
11686 (Info.CallStackDepth == 1 ||
11687 (Info.CallStackDepth == 2 && Callee->isInStdNamespace() &&
11688 Callee->getIdentifier() &&
11689 Callee->getIdentifier()->isStr("is_constant_evaluated")))) {
11690 // FIXME: Find a better way to avoid duplicated diagnostics.
11691 if (Info.EvalStatus.Diag)
11692 Info.report((Info.CallStackDepth == 1) ? E->getExprLoc()
11693 : Info.CurrentCall->CallLoc,
11694 diag::warn_is_constant_evaluated_always_true_constexpr)
11695 << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated"
11696 : "std::is_constant_evaluated");
11697 }
11698
11699 return Success(Info.InConstantContext, E);
11700 }
11701
11702 case Builtin::BI__builtin_ctz:
11703 case Builtin::BI__builtin_ctzl:
11704 case Builtin::BI__builtin_ctzll:
11705 case Builtin::BI__builtin_ctzs: {
11706 APSInt Val;
11707 if (!EvaluateInteger(E->getArg(0), Val, Info))
11708 return false;
11709 if (!Val)
11710 return Error(E);
11711
11712 return Success(Val.countTrailingZeros(), E);
11713 }
11714
11715 case Builtin::BI__builtin_eh_return_data_regno: {
11716 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
11717 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
11718 return Success(Operand, E);
11719 }
11720
11721 case Builtin::BI__builtin_expect:
11722 case Builtin::BI__builtin_expect_with_probability:
11723 return Visit(E->getArg(0));
11724
11725 case Builtin::BI__builtin_ffs:
11726 case Builtin::BI__builtin_ffsl:
11727 case Builtin::BI__builtin_ffsll: {
11728 APSInt Val;
11729 if (!EvaluateInteger(E->getArg(0), Val, Info))
11730 return false;
11731
11732 unsigned N = Val.countTrailingZeros();
11733 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
11734 }
11735
11736 case Builtin::BI__builtin_fpclassify: {
11737 APFloat Val(0.0);
11738 if (!EvaluateFloat(E->getArg(5), Val, Info))
11739 return false;
11740 unsigned Arg;
11741 switch (Val.getCategory()) {
11742 case APFloat::fcNaN: Arg = 0; break;
11743 case APFloat::fcInfinity: Arg = 1; break;
11744 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
11745 case APFloat::fcZero: Arg = 4; break;
11746 }
11747 return Visit(E->getArg(Arg));
11748 }
11749
11750 case Builtin::BI__builtin_isinf_sign: {
11751 APFloat Val(0.0);
11752 return EvaluateFloat(E->getArg(0), Val, Info) &&
11753 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
11754 }
11755
11756 case Builtin::BI__builtin_isinf: {
11757 APFloat Val(0.0);
11758 return EvaluateFloat(E->getArg(0), Val, Info) &&
11759 Success(Val.isInfinity() ? 1 : 0, E);
11760 }
11761
11762 case Builtin::BI__builtin_isfinite: {
11763 APFloat Val(0.0);
11764 return EvaluateFloat(E->getArg(0), Val, Info) &&
11765 Success(Val.isFinite() ? 1 : 0, E);
11766 }
11767
11768 case Builtin::BI__builtin_isnan: {
11769 APFloat Val(0.0);
11770 return EvaluateFloat(E->getArg(0), Val, Info) &&
11771 Success(Val.isNaN() ? 1 : 0, E);
11772 }
11773
11774 case Builtin::BI__builtin_isnormal: {
11775 APFloat Val(0.0);
11776 return EvaluateFloat(E->getArg(0), Val, Info) &&
11777 Success(Val.isNormal() ? 1 : 0, E);
11778 }
11779
11780 case Builtin::BI__builtin_parity:
11781 case Builtin::BI__builtin_parityl:
11782 case Builtin::BI__builtin_parityll: {
11783 APSInt Val;
11784 if (!EvaluateInteger(E->getArg(0), Val, Info))
11785 return false;
11786
11787 return Success(Val.countPopulation() % 2, E);
11788 }
11789
11790 case Builtin::BI__builtin_popcount:
11791 case Builtin::BI__builtin_popcountl:
11792 case Builtin::BI__builtin_popcountll: {
11793 APSInt Val;
11794 if (!EvaluateInteger(E->getArg(0), Val, Info))
11795 return false;
11796
11797 return Success(Val.countPopulation(), E);
11798 }
11799
11800 case Builtin::BI__builtin_rotateleft8:
11801 case Builtin::BI__builtin_rotateleft16:
11802 case Builtin::BI__builtin_rotateleft32:
11803 case Builtin::BI__builtin_rotateleft64:
11804 case Builtin::BI_rotl8: // Microsoft variants of rotate right
11805 case Builtin::BI_rotl16:
11806 case Builtin::BI_rotl:
11807 case Builtin::BI_lrotl:
11808 case Builtin::BI_rotl64: {
11809 APSInt Val, Amt;
11810 if (!EvaluateInteger(E->getArg(0), Val, Info) ||
11811 !EvaluateInteger(E->getArg(1), Amt, Info))
11812 return false;
11813
11814 return Success(Val.rotl(Amt.urem(Val.getBitWidth())), E);
11815 }
11816
11817 case Builtin::BI__builtin_rotateright8:
11818 case Builtin::BI__builtin_rotateright16:
11819 case Builtin::BI__builtin_rotateright32:
11820 case Builtin::BI__builtin_rotateright64:
11821 case Builtin::BI_rotr8: // Microsoft variants of rotate right
11822 case Builtin::BI_rotr16:
11823 case Builtin::BI_rotr:
11824 case Builtin::BI_lrotr:
11825 case Builtin::BI_rotr64: {
11826 APSInt Val, Amt;
11827 if (!EvaluateInteger(E->getArg(0), Val, Info) ||
11828 !EvaluateInteger(E->getArg(1), Amt, Info))
11829 return false;
11830
11831 return Success(Val.rotr(Amt.urem(Val.getBitWidth())), E);
11832 }
11833
11834 case Builtin::BIstrlen:
11835 case Builtin::BIwcslen:
11836 // A call to strlen is not a constant expression.
11837 if (Info.getLangOpts().CPlusPlus11)
11838 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
11839 << /*isConstexpr*/0 << /*isConstructor*/0
11840 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
11841 else
11842 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
11843 LLVM_FALLTHROUGH[[gnu::fallthrough]];
11844 case Builtin::BI__builtin_strlen:
11845 case Builtin::BI__builtin_wcslen: {
11846 // As an extension, we support __builtin_strlen() as a constant expression,
11847 // and support folding strlen() to a constant.
11848 LValue String;
11849 if (!EvaluatePointer(E->getArg(0), String, Info))
11850 return false;
11851
11852 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
11853
11854 // Fast path: if it's a string literal, search the string value.
11855 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
11856 String.getLValueBase().dyn_cast<const Expr *>())) {
11857 // The string literal may have embedded null characters. Find the first
11858 // one and truncate there.
11859 StringRef Str = S->getBytes();
11860 int64_t Off = String.Offset.getQuantity();
11861 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
11862 S->getCharByteWidth() == 1 &&
11863 // FIXME: Add fast-path for wchar_t too.
11864 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
11865 Str = Str.substr(Off);
11866
11867 StringRef::size_type Pos = Str.find(0);
11868 if (Pos != StringRef::npos)
11869 Str = Str.substr(0, Pos);
11870
11871 return Success(Str.size(), E);
11872 }
11873
11874 // Fall through to slow path to issue appropriate diagnostic.
11875 }
11876
11877 // Slow path: scan the bytes of the string looking for the terminating 0.
11878 for (uint64_t Strlen = 0; /**/; ++Strlen) {
11879 APValue Char;
11880 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
11881 !Char.isInt())
11882 return false;
11883 if (!Char.getInt())
11884 return Success(Strlen, E);
11885 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
11886 return false;
11887 }
11888 }
11889
11890 case Builtin::BIstrcmp:
11891 case Builtin::BIwcscmp:
11892 case Builtin::BIstrncmp:
11893 case Builtin::BIwcsncmp:
11894 case Builtin::BImemcmp:
11895 case Builtin::BIbcmp:
11896 case Builtin::BIwmemcmp:
11897 // A call to strlen is not a constant expression.
11898 if (Info.getLangOpts().CPlusPlus11)
11899 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
11900 << /*isConstexpr*/0 << /*isConstructor*/0
11901 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
11902 else
11903 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
11904 LLVM_FALLTHROUGH[[gnu::fallthrough]];
11905 case Builtin::BI__builtin_strcmp:
11906 case Builtin::BI__builtin_wcscmp:
11907 case Builtin::BI__builtin_strncmp:
11908 case Builtin::BI__builtin_wcsncmp:
11909 case Builtin::BI__builtin_memcmp:
11910 case Builtin::BI__builtin_bcmp:
11911 case Builtin::BI__builtin_wmemcmp: {
11912 LValue String1, String2;
11913 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
11914 !EvaluatePointer(E->getArg(1), String2, Info))
11915 return false;
11916
11917 uint64_t MaxLength = uint64_t(-1);
11918 if (BuiltinOp != Builtin::BIstrcmp &&
11919 BuiltinOp != Builtin::BIwcscmp &&
11920 BuiltinOp != Builtin::BI__builtin_strcmp &&
11921 BuiltinOp != Builtin::BI__builtin_wcscmp) {
11922 APSInt N;
11923 if (!EvaluateInteger(E->getArg(2), N, Info))
11924 return false;
11925 MaxLength = N.getExtValue();
11926 }
11927
11928 // Empty substrings compare equal by definition.
11929 if (MaxLength == 0u)
11930 return Success(0, E);
11931
11932 if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
11933 !String2.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
11934 String1.Designator.Invalid || String2.Designator.Invalid)
11935 return false;
11936
11937 QualType CharTy1 = String1.Designator.getType(Info.Ctx);
11938 QualType CharTy2 = String2.Designator.getType(Info.Ctx);
11939
11940 bool IsRawByte = BuiltinOp == Builtin::BImemcmp ||
11941 BuiltinOp == Builtin::BIbcmp ||
11942 BuiltinOp == Builtin::BI__builtin_memcmp ||
11943 BuiltinOp == Builtin::BI__builtin_bcmp;
11944
11945 assert(IsRawByte ||((void)0)
11946 (Info.Ctx.hasSameUnqualifiedType(((void)0)
11947 CharTy1, E->getArg(0)->getType()->getPointeeType()) &&((void)0)
11948 Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2)))((void)0);
11949
11950 // For memcmp, allow comparing any arrays of '[[un]signed] char' or
11951 // 'char8_t', but no other types.
11952 if (IsRawByte &&
11953 !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) {
11954 // FIXME: Consider using our bit_cast implementation to support this.
11955 Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported)
11956 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
11957 << CharTy1 << CharTy2;
11958 return false;
11959 }
11960
11961 const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) {
11962 return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) &&
11963 handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) &&
11964 Char1.isInt() && Char2.isInt();
11965 };
11966 const auto &AdvanceElems = [&] {
11967 return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) &&
11968 HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1);
11969 };
11970
11971 bool StopAtNull =
11972 (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp &&
11973 BuiltinOp != Builtin::BIwmemcmp &&
11974 BuiltinOp != Builtin::BI__builtin_memcmp &&
11975 BuiltinOp != Builtin::BI__builtin_bcmp &&
11976 BuiltinOp != Builtin::BI__builtin_wmemcmp);
11977 bool IsWide = BuiltinOp == Builtin::BIwcscmp ||
11978 BuiltinOp == Builtin::BIwcsncmp ||
11979 BuiltinOp == Builtin::BIwmemcmp ||
11980 BuiltinOp == Builtin::BI__builtin_wcscmp ||
11981 BuiltinOp == Builtin::BI__builtin_wcsncmp ||
11982 BuiltinOp == Builtin::BI__builtin_wmemcmp;
11983
11984 for (; MaxLength; --MaxLength) {
11985 APValue Char1, Char2;
11986 if (!ReadCurElems(Char1, Char2))
11987 return false;
11988 if (Char1.getInt().ne(Char2.getInt())) {
11989 if (IsWide) // wmemcmp compares with wchar_t signedness.
11990 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
11991 // memcmp always compares unsigned chars.
11992 return Success(Char1.getInt().ult(Char2.getInt()) ? -1 : 1, E);
11993 }
11994 if (StopAtNull && !Char1.getInt())
11995 return Success(0, E);
11996 assert(!(StopAtNull && !Char2.getInt()))((void)0);
11997 if (!AdvanceElems())
11998 return false;
11999 }
12000 // We hit the strncmp / memcmp limit.
12001 return Success(0, E);
12002 }
12003
12004 case Builtin::BI__atomic_always_lock_free:
12005 case Builtin::BI__atomic_is_lock_free:
12006 case Builtin::BI__c11_atomic_is_lock_free: {
12007 APSInt SizeVal;
12008 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
12009 return false;
12010
12011 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
12012 // of two less than or equal to the maximum inline atomic width, we know it
12013 // is lock-free. If the size isn't a power of two, or greater than the
12014 // maximum alignment where we promote atomics, we know it is not lock-free
12015 // (at least not in the sense of atomic_is_lock_free). Otherwise,
12016 // the answer can only be determined at runtime; for example, 16-byte
12017 // atomics have lock-free implementations on some, but not all,
12018 // x86-64 processors.
12019
12020 // Check power-of-two.
12021 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
12022 if (Size.isPowerOfTwo()) {
12023 // Check against inlining width.
12024 unsigned InlineWidthBits =
12025 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
12026 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
12027 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
12028 Size == CharUnits::One() ||
12029 E->getArg(1)->isNullPointerConstant(Info.Ctx,
12030 Expr::NPC_NeverValueDependent))
12031 // OK, we will inline appropriately-aligned operations of this size,
12032 // and _Atomic(T) is appropriately-aligned.
12033 return Success(1, E);
12034
12035 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
12036 castAs<PointerType>()->getPointeeType();
12037 if (!PointeeType->isIncompleteType() &&
12038 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
12039 // OK, we will inline operations on this object.
12040 return Success(1, E);
12041 }
12042 }
12043 }
12044
12045 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
12046 Success(0, E) : Error(E);
12047 }
12048 case Builtin::BI__builtin_add_overflow:
12049 case Builtin::BI__builtin_sub_overflow:
12050 case Builtin::BI__builtin_mul_overflow:
12051 case Builtin::BI__builtin_sadd_overflow:
12052 case Builtin::BI__builtin_uadd_overflow:
12053 case Builtin::BI__builtin_uaddl_overflow:
12054 case Builtin::BI__builtin_uaddll_overflow:
12055 case Builtin::BI__builtin_usub_overflow:
12056 case Builtin::BI__builtin_usubl_overflow:
12057 case Builtin::BI__builtin_usubll_overflow:
12058 case Builtin::BI__builtin_umul_overflow:
12059 case Builtin::BI__builtin_umull_overflow:
12060 case Builtin::BI__builtin_umulll_overflow:
12061 case Builtin::BI__builtin_saddl_overflow:
12062 case Builtin::BI__builtin_saddll_overflow:
12063 case Builtin::BI__builtin_ssub_overflow:
12064 case Builtin::BI__builtin_ssubl_overflow:
12065 case Builtin::BI__builtin_ssubll_overflow:
12066 case Builtin::BI__builtin_smul_overflow:
12067 case Builtin::BI__builtin_smull_overflow:
12068 case Builtin::BI__builtin_smulll_overflow: {
12069 LValue ResultLValue;
12070 APSInt LHS, RHS;
12071
12072 QualType ResultType = E->getArg(2)->getType()->getPointeeType();
12073 if (!EvaluateInteger(E->getArg(0), LHS, Info) ||
12074 !EvaluateInteger(E->getArg(1), RHS, Info) ||
12075 !EvaluatePointer(E->getArg(2), ResultLValue, Info))
12076 return false;
12077
12078 APSInt Result;
12079 bool DidOverflow = false;
12080
12081 // If the types don't have to match, enlarge all 3 to the largest of them.
12082 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
12083 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
12084 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
12085 bool IsSigned = LHS.isSigned() || RHS.isSigned() ||
12086 ResultType->isSignedIntegerOrEnumerationType();
12087 bool AllSigned = LHS.isSigned() && RHS.isSigned() &&
12088 ResultType->isSignedIntegerOrEnumerationType();
12089 uint64_t LHSSize = LHS.getBitWidth();
12090 uint64_t RHSSize = RHS.getBitWidth();
12091 uint64_t ResultSize = Info.Ctx.getTypeSize(ResultType);
12092 uint64_t MaxBits = std::max(std::max(LHSSize, RHSSize), ResultSize);
12093
12094 // Add an additional bit if the signedness isn't uniformly agreed to. We
12095 // could do this ONLY if there is a signed and an unsigned that both have
12096 // MaxBits, but the code to check that is pretty nasty. The issue will be
12097 // caught in the shrink-to-result later anyway.
12098 if (IsSigned && !AllSigned)
12099 ++MaxBits;
12100
12101 LHS = APSInt(LHS.extOrTrunc(MaxBits), !IsSigned);
12102 RHS = APSInt(RHS.extOrTrunc(MaxBits), !IsSigned);
12103 Result = APSInt(MaxBits, !IsSigned);
12104 }
12105
12106 // Find largest int.
12107 switch (BuiltinOp) {
12108 default:
12109 llvm_unreachable("Invalid value for BuiltinOp")__builtin_unreachable();
12110 case Builtin::BI__builtin_add_overflow:
12111 case Builtin::BI__builtin_sadd_overflow:
12112 case Builtin::BI__builtin_saddl_overflow:
12113 case Builtin::BI__builtin_saddll_overflow:
12114 case Builtin::BI__builtin_uadd_overflow:
12115 case Builtin::BI__builtin_uaddl_overflow:
12116 case Builtin::BI__builtin_uaddll_overflow:
12117 Result = LHS.isSigned() ? LHS.sadd_ov(RHS, DidOverflow)
12118 : LHS.uadd_ov(RHS, DidOverflow);
12119 break;
12120 case Builtin::BI__builtin_sub_overflow:
12121 case Builtin::BI__builtin_ssub_overflow:
12122 case Builtin::BI__builtin_ssubl_overflow:
12123 case Builtin::BI__builtin_ssubll_overflow:
12124 case Builtin::BI__builtin_usub_overflow:
12125 case Builtin::BI__builtin_usubl_overflow:
12126 case Builtin::BI__builtin_usubll_overflow:
12127 Result = LHS.isSigned() ? LHS.ssub_ov(RHS, DidOverflow)
12128 : LHS.usub_ov(RHS, DidOverflow);
12129 break;
12130 case Builtin::BI__builtin_mul_overflow:
12131 case Builtin::BI__builtin_smul_overflow:
12132 case Builtin::BI__builtin_smull_overflow:
12133 case Builtin::BI__builtin_smulll_overflow:
12134 case Builtin::BI__builtin_umul_overflow:
12135 case Builtin::BI__builtin_umull_overflow:
12136 case Builtin::BI__builtin_umulll_overflow:
12137 Result = LHS.isSigned() ? LHS.smul_ov(RHS, DidOverflow)
12138 : LHS.umul_ov(RHS, DidOverflow);
12139 break;
12140 }
12141
12142 // In the case where multiple sizes are allowed, truncate and see if
12143 // the values are the same.
12144 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
12145 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
12146 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
12147 // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead,
12148 // since it will give us the behavior of a TruncOrSelf in the case where
12149 // its parameter <= its size. We previously set Result to be at least the
12150 // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth
12151 // will work exactly like TruncOrSelf.
12152 APSInt Temp = Result.extOrTrunc(Info.Ctx.getTypeSize(ResultType));
12153 Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType());
12154
12155 if (!APSInt::isSameValue(Temp, Result))
12156 DidOverflow = true;
12157 Result = Temp;
12158 }
12159
12160 APValue APV{Result};
12161 if (!handleAssignment(Info, E, ResultLValue, ResultType, APV))
12162 return false;
12163 return Success(DidOverflow, E);
12164 }
12165 }
12166}
12167
12168/// Determine whether this is a pointer past the end of the complete
12169/// object referred to by the lvalue.
12170static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
12171 const LValue &LV) {
12172 // A null pointer can be viewed as being "past the end" but we don't
12173 // choose to look at it that way here.
12174 if (!LV.getLValueBase())
12175 return false;
12176
12177 // If the designator is valid and refers to a subobject, we're not pointing
12178 // past the end.
12179 if (!LV.getLValueDesignator().Invalid &&
12180 !LV.getLValueDesignator().isOnePastTheEnd())
12181 return false;
12182
12183 // A pointer to an incomplete type might be past-the-end if the type's size is
12184 // zero. We cannot tell because the type is incomplete.
12185 QualType Ty = getType(LV.getLValueBase());
12186 if (Ty->isIncompleteType())
12187 return true;
12188
12189 // We're a past-the-end pointer if we point to the byte after the object,
12190 // no matter what our type or path is.
12191 auto Size = Ctx.getTypeSizeInChars(Ty);
12192 return LV.getLValueOffset() == Size;
12193}
12194
12195namespace {
12196
12197/// Data recursive integer evaluator of certain binary operators.
12198///
12199/// We use a data recursive algorithm for binary operators so that we are able
12200/// to handle extreme cases of chained binary operators without causing stack
12201/// overflow.
12202class DataRecursiveIntBinOpEvaluator {
12203 struct EvalResult {
12204 APValue Val;
12205 bool Failed;
12206
12207 EvalResult() : Failed(false) { }
12208
12209 void swap(EvalResult &RHS) {
12210 Val.swap(RHS.Val);
12211 Failed = RHS.Failed;
12212 RHS.Failed = false;
12213 }
12214 };
12215
12216 struct Job {
12217 const Expr *E;
12218 EvalResult LHSResult; // meaningful only for binary operator expression.
12219 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
12220
12221 Job() = default;
12222 Job(Job &&) = default;
12223
12224 void startSpeculativeEval(EvalInfo &Info) {
12225 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
12226 }
12227
12228 private:
12229 SpeculativeEvaluationRAII SpecEvalRAII;
12230 };
12231
12232 SmallVector<Job, 16> Queue;
12233
12234 IntExprEvaluator &IntEval;
12235 EvalInfo &Info;
12236 APValue &FinalResult;
12237
12238public:
12239 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
12240 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
12241
12242 /// True if \param E is a binary operator that we are going to handle
12243 /// data recursively.
12244 /// We handle binary operators that are comma, logical, or that have operands
12245 /// with integral or enumeration type.
12246 static bool shouldEnqueue(const BinaryOperator *E) {
12247 return E->getOpcode() == BO_Comma || E->isLogicalOp() ||
12248 (E->isPRValue() && E->getType()->isIntegralOrEnumerationType() &&
12249 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
12250 E->getRHS()->getType()->isIntegralOrEnumerationType());
12251 }
12252
12253 bool Traverse(const BinaryOperator *E) {
12254 enqueue(E);
12255 EvalResult PrevResult;
12256 while (!Queue.empty())
12257 process(PrevResult);
12258
12259 if (PrevResult.Failed) return false;
12260
12261 FinalResult.swap(PrevResult.Val);
12262 return true;
12263 }
12264
12265private:
12266 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
12267 return IntEval.Success(Value, E, Result);
12268 }
12269 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
12270 return IntEval.Success(Value, E, Result);
12271 }
12272 bool Error(const Expr *E) {
12273 return IntEval.Error(E);
12274 }
12275 bool Error(const Expr *E, diag::kind D) {
12276 return IntEval.Error(E, D);
12277 }
12278
12279 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
12280 return Info.CCEDiag(E, D);
12281 }
12282
12283 // Returns true if visiting the RHS is necessary, false otherwise.
12284 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
12285 bool &SuppressRHSDiags);
12286
12287 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
12288 const BinaryOperator *E, APValue &Result);
12289
12290 void EvaluateExpr(const Expr *E, EvalResult &Result) {
12291 Result.Failed = !Evaluate(Result.Val, Info, E);
12292 if (Result.Failed)
12293 Result.Val = APValue();
12294 }
12295
12296 void process(EvalResult &Result);
12297
12298 void enqueue(const Expr *E) {
12299 E = E->IgnoreParens();
12300 Queue.resize(Queue.size()+1);
12301 Queue.back().E = E;
12302 Queue.back().Kind = Job::AnyExprKind;
12303 }
12304};
12305
12306}
12307
12308bool DataRecursiveIntBinOpEvaluator::
12309 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
12310 bool &SuppressRHSDiags) {
12311 if (E->getOpcode() == BO_Comma) {
12312 // Ignore LHS but note if we could not evaluate it.
12313 if (LHSResult.Failed)
12314 return Info.noteSideEffect();
12315 return true;
12316 }
12317
12318 if (E->isLogicalOp()) {
12319 bool LHSAsBool;
12320 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
12321 // We were able to evaluate the LHS, see if we can get away with not
12322 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
12323 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
12324 Success(LHSAsBool, E, LHSResult.Val);
12325 return false; // Ignore RHS
12326 }
12327 } else {
12328 LHSResult.Failed = true;
12329
12330 // Since we weren't able to evaluate the left hand side, it
12331 // might have had side effects.
12332 if (!Info.noteSideEffect())
12333 return false;
12334
12335 // We can't evaluate the LHS; however, sometimes the result
12336 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
12337 // Don't ignore RHS and suppress diagnostics from this arm.
12338 SuppressRHSDiags = true;
12339 }
12340
12341 return true;
12342 }
12343
12344 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&((void)0)
12345 E->getRHS()->getType()->isIntegralOrEnumerationType())((void)0);
12346
12347 if (LHSResult.Failed && !Info.noteFailure())
12348 return false; // Ignore RHS;
12349
12350 return true;
12351}
12352
12353static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
12354 bool IsSub) {
12355 // Compute the new offset in the appropriate width, wrapping at 64 bits.
12356 // FIXME: When compiling for a 32-bit target, we should use 32-bit
12357 // offsets.
12358 assert(!LVal.hasLValuePath() && "have designator for integer lvalue")((void)0);
12359 CharUnits &Offset = LVal.getLValueOffset();
12360 uint64_t Offset64 = Offset.getQuantity();
12361 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
12362 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64
12363 : Offset64 + Index64);
12364}
12365
12366bool DataRecursiveIntBinOpEvaluator::
12367 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
12368 const BinaryOperator *E, APValue &Result) {
12369 if (E->getOpcode() == BO_Comma) {
12370 if (RHSResult.Failed)
12371 return false;
12372 Result = RHSResult.Val;
12373 return true;
12374 }
12375
12376 if (E->isLogicalOp()) {
12377 bool lhsResult, rhsResult;
12378 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
12379 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
12380
12381 if (LHSIsOK) {
12382 if (RHSIsOK) {
12383 if (E->getOpcode() == BO_LOr)
12384 return Success(lhsResult || rhsResult, E, Result);
12385 else
12386 return Success(lhsResult && rhsResult, E, Result);
12387 }
12388 } else {
12389 if (RHSIsOK) {
12390 // We can't evaluate the LHS; however, sometimes the result
12391 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
12392 if (rhsResult == (E->getOpcode() == BO_LOr))
12393 return Success(rhsResult, E, Result);
12394 }
12395 }
12396
12397 return false;
12398 }
12399
12400 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&((void)0)
12401 E->getRHS()->getType()->isIntegralOrEnumerationType())((void)0);
12402
12403 if (LHSResult.Failed || RHSResult.Failed)
12404 return false;
12405
12406 const APValue &LHSVal = LHSResult.Val;
12407 const APValue &RHSVal = RHSResult.Val;
12408
12409 // Handle cases like (unsigned long)&a + 4.
12410 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
12411 Result = LHSVal;
12412 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
12413 return true;
12414 }
12415
12416 // Handle cases like 4 + (unsigned long)&a
12417 if (E->getOpcode() == BO_Add &&
12418 RHSVal.isLValue() && LHSVal.isInt()) {
12419 Result = RHSVal;
12420 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
12421 return true;
12422 }
12423
12424 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
12425 // Handle (intptr_t)&&A - (intptr_t)&&B.
12426 if (!LHSVal.getLValueOffset().isZero() ||
12427 !RHSVal.getLValueOffset().isZero())
12428 return false;
12429 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
12430 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
12431 if (!LHSExpr || !RHSExpr)
12432 return false;
12433 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
12434 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
12435 if (!LHSAddrExpr || !RHSAddrExpr)
12436 return false;
12437 // Make sure both labels come from the same function.
12438 if (LHSAddrExpr->getLabel()->getDeclContext() !=
12439 RHSAddrExpr->getLabel()->getDeclContext())
12440 return false;
12441 Result = APValue(LHSAddrExpr, RHSAddrExpr);
12442 return true;
12443 }
12444
12445 // All the remaining cases expect both operands to be an integer
12446 if (!LHSVal.isInt() || !RHSVal.isInt())
12447 return Error(E);
12448
12449 // Set up the width and signedness manually, in case it can't be deduced
12450 // from the operation we're performing.
12451 // FIXME: Don't do this in the cases where we can deduce it.
12452 APSInt Value(Info.Ctx.getIntWidth(E->getType()),
12453 E->getType()->isUnsignedIntegerOrEnumerationType());
12454 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
12455 RHSVal.getInt(), Value))
12456 return false;
12457 return Success(Value, E, Result);
12458}
12459
12460void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
12461 Job &job = Queue.back();
12462
12463 switch (job.Kind) {
12464 case Job::AnyExprKind: {
12465 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
12466 if (shouldEnqueue(Bop)) {
12467 job.Kind = Job::BinOpKind;
12468 enqueue(Bop->getLHS());
12469 return;
12470 }
12471 }
12472
12473 EvaluateExpr(job.E, Result);
12474 Queue.pop_back();
12475 return;
12476 }
12477
12478 case Job::BinOpKind: {
12479 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
12480 bool SuppressRHSDiags = false;
12481 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
12482 Queue.pop_back();
12483 return;
12484 }
12485 if (SuppressRHSDiags)
12486 job.startSpeculativeEval(Info);
12487 job.LHSResult.swap(Result);
12488 job.Kind = Job::BinOpVisitedLHSKind;
12489 enqueue(Bop->getRHS());
12490 return;
12491 }
12492
12493 case Job::BinOpVisitedLHSKind: {
12494 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
12495 EvalResult RHS;
12496 RHS.swap(Result);
12497 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
12498 Queue.pop_back();
12499 return;
12500 }
12501 }
12502
12503 llvm_unreachable("Invalid Job::Kind!")__builtin_unreachable();
12504}
12505
12506namespace {
12507enum class CmpResult {
12508 Unequal,
12509 Less,
12510 Equal,
12511 Greater,
12512 Unordered,
12513};
12514}
12515
12516template <class SuccessCB, class AfterCB>
12517static bool
12518EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E,
12519 SuccessCB &&Success, AfterCB &&DoAfter) {
12520 assert(!E->isValueDependent())((void)0);
12521 assert(E->isComparisonOp() && "expected comparison operator")((void)0);
12522 assert((E->getOpcode() == BO_Cmp ||((void)0)
12523 E->getType()->isIntegralOrEnumerationType()) &&((void)0)
12524 "unsupported binary expression evaluation")((void)0);
12525 auto Error = [&](const Expr *E) {
12526 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
12527 return false;
12528 };
12529
12530 bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp;
12531 bool IsEquality = E->isEqualityOp();
12532
12533 QualType LHSTy = E->getLHS()->getType();
12534 QualType RHSTy = E->getRHS()->getType();
12535
12536 if (LHSTy->isIntegralOrEnumerationType() &&
12537 RHSTy->isIntegralOrEnumerationType()) {
12538 APSInt LHS, RHS;
12539 bool LHSOK = EvaluateInteger(E->getLHS(), LHS, Info);
12540 if (!LHSOK && !Info.noteFailure())
12541 return false;
12542 if (!EvaluateInteger(E->getRHS(), RHS, Info) || !LHSOK)
12543 return false;
12544 if (LHS < RHS)
12545 return Success(CmpResult::Less, E);
12546 if (LHS > RHS)
12547 return Success(CmpResult::Greater, E);
12548 return Success(CmpResult::Equal, E);
12549 }
12550
12551 if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) {
12552 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHSTy));
12553 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHSTy));
12554
12555 bool LHSOK = EvaluateFixedPointOrInteger(E->getLHS(), LHSFX, Info);
12556 if (!LHSOK && !Info.noteFailure())
12557 return false;
12558 if (!EvaluateFixedPointOrInteger(E->getRHS(), RHSFX, Info) || !LHSOK)
12559 return false;
12560 if (LHSFX < RHSFX)
12561 return Success(CmpResult::Less, E);
12562 if (LHSFX > RHSFX)
12563 return Success(CmpResult::Greater, E);
12564 return Success(CmpResult::Equal, E);
12565 }
12566
12567 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
12568 ComplexValue LHS, RHS;
12569 bool LHSOK;
12570 if (E->isAssignmentOp()) {
12571 LValue LV;
12572 EvaluateLValue(E->getLHS(), LV, Info);
12573 LHSOK = false;
12574 } else if (LHSTy->isRealFloatingType()) {
12575 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
12576 if (LHSOK) {
12577 LHS.makeComplexFloat();
12578 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
12579 }
12580 } else {
12581 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
12582 }
12583 if (!LHSOK && !Info.noteFailure())
12584 return false;
12585
12586 if (E->getRHS()->getType()->isRealFloatingType()) {
12587 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
12588 return false;
12589 RHS.makeComplexFloat();
12590 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
12591 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
12592 return false;
12593
12594 if (LHS.isComplexFloat()) {
12595 APFloat::cmpResult CR_r =
12596 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
12597 APFloat::cmpResult CR_i =
12598 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
12599 bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual;
12600 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
12601 } else {
12602 assert(IsEquality && "invalid complex comparison")((void)0);
12603 bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
12604 LHS.getComplexIntImag() == RHS.getComplexIntImag();
12605 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
12606 }
12607 }
12608
12609 if (LHSTy->isRealFloatingType() &&
12610 RHSTy->isRealFloatingType()) {
12611 APFloat RHS(0.0), LHS(0.0);
12612
12613 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
12614 if (!LHSOK && !Info.noteFailure())
12615 return false;
12616
12617 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
12618 return false;
12619
12620 assert(E->isComparisonOp() && "Invalid binary operator!")((void)0);
12621 llvm::APFloatBase::cmpResult APFloatCmpResult = LHS.compare(RHS);
12622 if (!Info.InConstantContext &&
12623 APFloatCmpResult == APFloat::cmpUnordered &&
12624 E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).isFPConstrained()) {
12625 // Note: Compares may raise invalid in some cases involving NaN or sNaN.
12626 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
12627 return false;
12628 }
12629 auto GetCmpRes = [&]() {
12630 switch (APFloatCmpResult) {
12631 case APFloat::cmpEqual:
12632 return CmpResult::Equal;
12633 case APFloat::cmpLessThan:
12634 return CmpResult::Less;
12635 case APFloat::cmpGreaterThan:
12636 return CmpResult::Greater;
12637 case APFloat::cmpUnordered:
12638 return CmpResult::Unordered;
12639 }
12640 llvm_unreachable("Unrecognised APFloat::cmpResult enum")__builtin_unreachable();
12641 };
12642 return Success(GetCmpRes(), E);
12643 }
12644
12645 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
12646 LValue LHSValue, RHSValue;
12647
12648 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
12649 if (!LHSOK && !Info.noteFailure())
12650 return false;
12651
12652 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12653 return false;
12654
12655 // Reject differing bases from the normal codepath; we special-case
12656 // comparisons to null.
12657 if (!HasSameBase(LHSValue, RHSValue)) {
12658 // Inequalities and subtractions between unrelated pointers have
12659 // unspecified or undefined behavior.
12660 if (!IsEquality) {
12661 Info.FFDiag(E, diag::note_constexpr_pointer_comparison_unspecified);
12662 return false;
12663 }
12664 // A constant address may compare equal to the address of a symbol.
12665 // The one exception is that address of an object cannot compare equal
12666 // to a null pointer constant.
12667 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
12668 (!RHSValue.Base && !RHSValue.Offset.isZero()))
12669 return Error(E);
12670 // It's implementation-defined whether distinct literals will have
12671 // distinct addresses. In clang, the result of such a comparison is
12672 // unspecified, so it is not a constant expression. However, we do know
12673 // that the address of a literal will be non-null.
12674 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
12675 LHSValue.Base && RHSValue.Base)
12676 return Error(E);
12677 // We can't tell whether weak symbols will end up pointing to the same
12678 // object.
12679 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
12680 return Error(E);
12681 // We can't compare the address of the start of one object with the
12682 // past-the-end address of another object, per C++ DR1652.
12683 if ((LHSValue.Base && LHSValue.Offset.isZero() &&
12684 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
12685 (RHSValue.Base && RHSValue.Offset.isZero() &&
12686 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
12687 return Error(E);
12688 // We can't tell whether an object is at the same address as another
12689 // zero sized object.
12690 if ((RHSValue.Base && isZeroSized(LHSValue)) ||
12691 (LHSValue.Base && isZeroSized(RHSValue)))
12692 return Error(E);
12693 return Success(CmpResult::Unequal, E);
12694 }
12695
12696 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
12697 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
12698
12699 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
12700 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
12701
12702 // C++11 [expr.rel]p3:
12703 // Pointers to void (after pointer conversions) can be compared, with a
12704 // result defined as follows: If both pointers represent the same
12705 // address or are both the null pointer value, the result is true if the
12706 // operator is <= or >= and false otherwise; otherwise the result is
12707 // unspecified.
12708 // We interpret this as applying to pointers to *cv* void.
12709 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational)
12710 Info.CCEDiag(E, diag::note_constexpr_void_comparison);
12711
12712 // C++11 [expr.rel]p2:
12713 // - If two pointers point to non-static data members of the same object,
12714 // or to subobjects or array elements fo such members, recursively, the
12715 // pointer to the later declared member compares greater provided the
12716 // two members have the same access control and provided their class is
12717 // not a union.
12718 // [...]
12719 // - Otherwise pointer comparisons are unspecified.
12720 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) {
12721 bool WasArrayIndex;
12722 unsigned Mismatch = FindDesignatorMismatch(
12723 getType(LHSValue.Base), LHSDesignator, RHSDesignator, WasArrayIndex);
12724 // At the point where the designators diverge, the comparison has a
12725 // specified value if:
12726 // - we are comparing array indices
12727 // - we are comparing fields of a union, or fields with the same access
12728 // Otherwise, the result is unspecified and thus the comparison is not a
12729 // constant expression.
12730 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
12731 Mismatch < RHSDesignator.Entries.size()) {
12732 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
12733 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
12734 if (!LF && !RF)
12735 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
12736 else if (!LF)
12737 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
12738 << getAsBaseClass(LHSDesignator.Entries[Mismatch])
12739 << RF->getParent() << RF;
12740 else if (!RF)
12741 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
12742 << getAsBaseClass(RHSDesignator.Entries[Mismatch])
12743 << LF->getParent() << LF;
12744 else if (!LF->getParent()->isUnion() &&
12745 LF->getAccess() != RF->getAccess())
12746 Info.CCEDiag(E,
12747 diag::note_constexpr_pointer_comparison_differing_access)
12748 << LF << LF->getAccess() << RF << RF->getAccess()
12749 << LF->getParent();
12750 }
12751 }
12752
12753 // The comparison here must be unsigned, and performed with the same
12754 // width as the pointer.
12755 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
12756 uint64_t CompareLHS = LHSOffset.getQuantity();
12757 uint64_t CompareRHS = RHSOffset.getQuantity();
12758 assert(PtrSize <= 64 && "Unexpected pointer width")((void)0);
12759 uint64_t Mask = ~0ULL >> (64 - PtrSize);
12760 CompareLHS &= Mask;
12761 CompareRHS &= Mask;
12762
12763 // If there is a base and this is a relational operator, we can only
12764 // compare pointers within the object in question; otherwise, the result
12765 // depends on where the object is located in memory.
12766 if (!LHSValue.Base.isNull() && IsRelational) {
12767 QualType BaseTy = getType(LHSValue.Base);
12768 if (BaseTy->isIncompleteType())
12769 return Error(E);
12770 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
12771 uint64_t OffsetLimit = Size.getQuantity();
12772 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
12773 return Error(E);
12774 }
12775
12776 if (CompareLHS < CompareRHS)
12777 return Success(CmpResult::Less, E);
12778 if (CompareLHS > CompareRHS)
12779 return Success(CmpResult::Greater, E);
12780 return Success(CmpResult::Equal, E);
12781 }
12782
12783 if (LHSTy->isMemberPointerType()) {
12784 assert(IsEquality && "unexpected member pointer operation")((void)0);
12785 assert(RHSTy->isMemberPointerType() && "invalid comparison")((void)0);
12786
12787 MemberPtr LHSValue, RHSValue;
12788
12789 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
12790 if (!LHSOK && !Info.noteFailure())
12791 return false;
12792
12793 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12794 return false;
12795
12796 // C++11 [expr.eq]p2:
12797 // If both operands are null, they compare equal. Otherwise if only one is
12798 // null, they compare unequal.
12799 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
12800 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
12801 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
12802 }
12803
12804 // Otherwise if either is a pointer to a virtual member function, the
12805 // result is unspecified.
12806 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
12807 if (MD->isVirtual())
12808 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
12809 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
12810 if (MD->isVirtual())
12811 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
12812
12813 // Otherwise they compare equal if and only if they would refer to the
12814 // same member of the same most derived object or the same subobject if
12815 // they were dereferenced with a hypothetical object of the associated
12816 // class type.
12817 bool Equal = LHSValue == RHSValue;
12818 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
12819 }
12820
12821 if (LHSTy->isNullPtrType()) {
12822 assert(E->isComparisonOp() && "unexpected nullptr operation")((void)0);
12823 assert(RHSTy->isNullPtrType() && "missing pointer conversion")((void)0);
12824 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
12825 // are compared, the result is true of the operator is <=, >= or ==, and
12826 // false otherwise.
12827 return Success(CmpResult::Equal, E);
12828 }
12829
12830 return DoAfter();
12831}
12832
12833bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) {
12834 if (!CheckLiteralType(Info, E))
12835 return false;
12836
12837 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
12838 ComparisonCategoryResult CCR;
12839 switch (CR) {
12840 case CmpResult::Unequal:
12841 llvm_unreachable("should never produce Unequal for three-way comparison")__builtin_unreachable();
12842 case CmpResult::Less:
12843 CCR = ComparisonCategoryResult::Less;
12844 break;
12845 case CmpResult::Equal:
12846 CCR = ComparisonCategoryResult::Equal;
12847 break;
12848 case CmpResult::Greater:
12849 CCR = ComparisonCategoryResult::Greater;
12850 break;
12851 case CmpResult::Unordered:
12852 CCR = ComparisonCategoryResult::Unordered;
12853 break;
12854 }
12855 // Evaluation succeeded. Lookup the information for the comparison category
12856 // type and fetch the VarDecl for the result.
12857 const ComparisonCategoryInfo &CmpInfo =
12858 Info.Ctx.CompCategories.getInfoForType(E->getType());
12859 const VarDecl *VD = CmpInfo.getValueInfo(CmpInfo.makeWeakResult(CCR))->VD;
12860 // Check and evaluate the result as a constant expression.
12861 LValue LV;
12862 LV.set(VD);
12863 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
12864 return false;
12865 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
12866 ConstantExprKind::Normal);
12867 };
12868 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
12869 return ExprEvaluatorBaseTy::VisitBinCmp(E);
12870 });
12871}
12872
12873bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
12874 // We don't support assignment in C. C++ assignments don't get here because
12875 // assignment is an lvalue in C++.
12876 if (E->isAssignmentOp()) {
12877 Error(E);
12878 if (!Info.noteFailure())
12879 return false;
12880 }
12881
12882 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
12883 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
12884
12885 assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() ||((void)0)
12886 !E->getRHS()->getType()->isIntegralOrEnumerationType()) &&((void)0)
12887 "DataRecursiveIntBinOpEvaluator should have handled integral types")((void)0);
12888
12889 if (E->isComparisonOp()) {
12890 // Evaluate builtin binary comparisons by evaluating them as three-way
12891 // comparisons and then translating the result.
12892 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
12893 assert((CR != CmpResult::Unequal || E->isEqualityOp()) &&((void)0)
12894 "should only produce Unequal for equality comparisons")((void)0);
12895 bool IsEqual = CR == CmpResult::Equal,
12896 IsLess = CR == CmpResult::Less,
12897 IsGreater = CR == CmpResult::Greater;
12898 auto Op = E->getOpcode();
12899 switch (Op) {
12900 default:
12901 llvm_unreachable("unsupported binary operator")__builtin_unreachable();
12902 case BO_EQ:
12903 case BO_NE:
12904 return Success(IsEqual == (Op == BO_EQ), E);
12905 case BO_LT:
12906 return Success(IsLess, E);
12907 case BO_GT:
12908 return Success(IsGreater, E);
12909 case BO_LE:
12910 return Success(IsEqual || IsLess, E);
12911 case BO_GE:
12912 return Success(IsEqual || IsGreater, E);
12913 }
12914 };
12915 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
12916 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
12917 });
12918 }
12919
12920 QualType LHSTy = E->getLHS()->getType();
12921 QualType RHSTy = E->getRHS()->getType();
12922
12923 if (LHSTy->isPointerType() && RHSTy->isPointerType() &&
12924 E->getOpcode() == BO_Sub) {
12925 LValue LHSValue, RHSValue;
12926
12927 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
12928 if (!LHSOK && !Info.noteFailure())
12929 return false;
12930
12931 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12932 return false;
12933
12934 // Reject differing bases from the normal codepath; we special-case
12935 // comparisons to null.
12936 if (!HasSameBase(LHSValue, RHSValue)) {
12937 // Handle &&A - &&B.
12938 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
12939 return Error(E);
12940 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>();
12941 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>();
12942 if (!LHSExpr || !RHSExpr)
12943 return Error(E);
12944 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
12945 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
12946 if (!LHSAddrExpr || !RHSAddrExpr)
12947 return Error(E);
12948 // Make sure both labels come from the same function.
12949 if (LHSAddrExpr->getLabel()->getDeclContext() !=
12950 RHSAddrExpr->getLabel()->getDeclContext())
12951 return Error(E);
12952 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
12953 }
12954 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
12955 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
12956
12957 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
12958 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
12959
12960 // C++11 [expr.add]p6:
12961 // Unless both pointers point to elements of the same array object, or
12962 // one past the last element of the array object, the behavior is
12963 // undefined.
12964 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
12965 !AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator,
12966 RHSDesignator))
12967 Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
12968
12969 QualType Type = E->getLHS()->getType();
12970 QualType ElementType = Type->castAs<PointerType>()->getPointeeType();
12971
12972 CharUnits ElementSize;
12973 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
12974 return false;
12975
12976 // As an extension, a type may have zero size (empty struct or union in
12977 // C, array of zero length). Pointer subtraction in such cases has
12978 // undefined behavior, so is not constant.
12979 if (ElementSize.isZero()) {
12980 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
12981 << ElementType;
12982 return false;
12983 }
12984
12985 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
12986 // and produce incorrect results when it overflows. Such behavior
12987 // appears to be non-conforming, but is common, so perhaps we should
12988 // assume the standard intended for such cases to be undefined behavior
12989 // and check for them.
12990
12991 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
12992 // overflow in the final conversion to ptrdiff_t.
12993 APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
12994 APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
12995 APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true),
12996 false);
12997 APSInt TrueResult = (LHS - RHS) / ElemSize;
12998 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
12999
13000 if (Result.extend(65) != TrueResult &&
13001 !HandleOverflow(Info, E, TrueResult, E->getType()))
13002 return false;
13003 return Success(Result, E);
13004 }
13005
13006 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13007}
13008
13009/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
13010/// a result as the expression's type.
13011bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
13012 const UnaryExprOrTypeTraitExpr *E) {
13013 switch(E->getKind()) {
13014 case UETT_PreferredAlignOf:
13015 case UETT_AlignOf: {
13016 if (E->isArgumentType())
13017 return Success(GetAlignOfType(Info, E->getArgumentType(), E->getKind()),
13018 E);
13019 else
13020 return Success(GetAlignOfExpr(Info, E->getArgumentExpr(), E->getKind()),
13021 E);
13022 }
13023
13024 case UETT_VecStep: {
13025 QualType Ty = E->getTypeOfArgument();
13026
13027 if (Ty->isVectorType()) {
13028 unsigned n = Ty->castAs<VectorType>()->getNumElements();
13029
13030 // The vec_step built-in functions that take a 3-component
13031 // vector return 4. (OpenCL 1.1 spec 6.11.12)
13032 if (n == 3)
13033 n = 4;
13034
13035 return Success(n, E);
13036 } else
13037 return Success(1, E);
13038 }
13039
13040 case UETT_SizeOf: {
13041 QualType SrcTy = E->getTypeOfArgument();
13042 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
13043 // the result is the size of the referenced type."
13044 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
13045 SrcTy = Ref->getPointeeType();
13046
13047 CharUnits Sizeof;
13048 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
13049 return false;
13050 return Success(Sizeof, E);
13051 }
13052 case UETT_OpenMPRequiredSimdAlign:
13053 assert(E->isArgumentType())((void)0);
13054 return Success(
13055 Info.Ctx.toCharUnitsFromBits(
13056 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
13057 .getQuantity(),
13058 E);
13059 }
13060
13061 llvm_unreachable("unknown expr/type trait")__builtin_unreachable();
13062}
13063
13064bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
13065 CharUnits Result;
13066 unsigned n = OOE->getNumComponents();
13067 if (n == 0)
13068 return Error(OOE);
13069 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
13070 for (unsigned i = 0; i != n; ++i) {
13071 OffsetOfNode ON = OOE->getComponent(i);
13072 switch (ON.getKind()) {
13073 case OffsetOfNode::Array: {
13074 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
13075 APSInt IdxResult;
13076 if (!EvaluateInteger(Idx, IdxResult, Info))
13077 return false;
13078 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
13079 if (!AT)
13080 return Error(OOE);
13081 CurrentType = AT->getElementType();
13082 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
13083 Result += IdxResult.getSExtValue() * ElementSize;
13084 break;
13085 }
13086
13087 case OffsetOfNode::Field: {
13088 FieldDecl *MemberDecl = ON.getField();
13089 const RecordType *RT = CurrentType->getAs<RecordType>();
13090 if (!RT)
13091 return Error(OOE);
13092 RecordDecl *RD = RT->getDecl();
13093 if (RD->isInvalidDecl()) return false;
13094 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
13095 unsigned i = MemberDecl->getFieldIndex();
13096 assert(i < RL.getFieldCount() && "offsetof field in wrong type")((void)0);
13097 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
13098 CurrentType = MemberDecl->getType().getNonReferenceType();
13099 break;
13100 }
13101
13102 case OffsetOfNode::Identifier:
13103 llvm_unreachable("dependent __builtin_offsetof")__builtin_unreachable();
13104
13105 case OffsetOfNode::Base: {
13106 CXXBaseSpecifier *BaseSpec = ON.getBase();
13107 if (BaseSpec->isVirtual())
13108 return Error(OOE);
13109
13110 // Find the layout of the class whose base we are looking into.
13111 const RecordType *RT = CurrentType->getAs<RecordType>();
13112 if (!RT)
13113 return Error(OOE);
13114 RecordDecl *RD = RT->getDecl();
13115 if (RD->isInvalidDecl()) return false;
13116 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
13117
13118 // Find the base class itself.
13119 CurrentType = BaseSpec->getType();
13120 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
13121 if (!BaseRT)
13122 return Error(OOE);
13123
13124 // Add the offset to the base.
13125 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
13126 break;
13127 }
13128 }
13129 }
13130 return Success(Result, OOE);
13131}
13132
13133bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13134 switch (E->getOpcode()) {
13135 default:
13136 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
13137 // See C99 6.6p3.
13138 return Error(E);
13139 case UO_Extension:
13140 // FIXME: Should extension allow i-c-e extension expressions in its scope?
13141 // If so, we could clear the diagnostic ID.
13142 return Visit(E->getSubExpr());
13143 case UO_Plus:
13144 // The result is just the value.
13145 return Visit(E->getSubExpr());
13146 case UO_Minus: {
13147 if (!Visit(E->getSubExpr()))
13148 return false;
13149 if (!Result.isInt()) return Error(E);
13150 const APSInt &Value = Result.getInt();
13151 if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() &&
13152 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
13153 E->getType()))
13154 return false;
13155 return Success(-Value, E);
13156 }
13157 case UO_Not: {
13158 if (!Visit(E->getSubExpr()))
13159 return false;
13160 if (!Result.isInt()) return Error(E);
13161 return Success(~Result.getInt(), E);
13162 }
13163 case UO_LNot: {
13164 bool bres;
13165 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
13166 return false;
13167 return Success(!bres, E);
13168 }
13169 }
13170}
13171
13172/// HandleCast - This is used to evaluate implicit or explicit casts where the
13173/// result type is integer.
13174bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
13175 const Expr *SubExpr = E->getSubExpr();
13176 QualType DestType = E->getType();
13177 QualType SrcType = SubExpr->getType();
13178
13179 switch (E->getCastKind()) {
13180 case CK_BaseToDerived:
13181 case CK_DerivedToBase:
13182 case CK_UncheckedDerivedToBase:
13183 case CK_Dynamic:
13184 case CK_ToUnion:
13185 case CK_ArrayToPointerDecay:
13186 case CK_FunctionToPointerDecay:
13187 case CK_NullToPointer:
13188 case CK_NullToMemberPointer:
13189 case CK_BaseToDerivedMemberPointer:
13190 case CK_DerivedToBaseMemberPointer:
13191 case CK_ReinterpretMemberPointer:
13192 case CK_ConstructorConversion:
13193 case CK_IntegralToPointer:
13194 case CK_ToVoid:
13195 case CK_VectorSplat:
13196 case CK_IntegralToFloating:
13197 case CK_FloatingCast:
13198 case CK_CPointerToObjCPointerCast:
13199 case CK_BlockPointerToObjCPointerCast:
13200 case CK_AnyPointerToBlockPointerCast:
13201 case CK_ObjCObjectLValueCast:
13202 case CK_FloatingRealToComplex:
13203 case CK_FloatingComplexToReal:
13204 case CK_FloatingComplexCast:
13205 case CK_FloatingComplexToIntegralComplex:
13206 case CK_IntegralRealToComplex:
13207 case CK_IntegralComplexCast:
13208 case CK_IntegralComplexToFloatingComplex:
13209 case CK_BuiltinFnToFnPtr:
13210 case CK_ZeroToOCLOpaqueType:
13211 case CK_NonAtomicToAtomic:
13212 case CK_AddressSpaceConversion:
13213 case CK_IntToOCLSampler:
13214 case CK_FloatingToFixedPoint:
13215 case CK_FixedPointToFloating:
13216 case CK_FixedPointCast:
13217 case CK_IntegralToFixedPoint:
13218 case CK_MatrixCast:
13219 llvm_unreachable("invalid cast kind for integral value")__builtin_unreachable();
13220
13221 case CK_BitCast:
13222 case CK_Dependent:
13223 case CK_LValueBitCast:
13224 case CK_ARCProduceObject:
13225 case CK_ARCConsumeObject:
13226 case CK_ARCReclaimReturnedObject:
13227 case CK_ARCExtendBlockObject:
13228 case CK_CopyAndAutoreleaseBlockObject:
13229 return Error(E);
13230
13231 case CK_UserDefinedConversion:
13232 case CK_LValueToRValue:
13233 case CK_AtomicToNonAtomic:
13234 case CK_NoOp:
13235 case CK_LValueToRValueBitCast:
13236 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13237
13238 case CK_MemberPointerToBoolean:
13239 case CK_PointerToBoolean:
13240 case CK_IntegralToBoolean:
13241 case CK_FloatingToBoolean:
13242 case CK_BooleanToSignedIntegral:
13243 case CK_FloatingComplexToBoolean:
13244 case CK_IntegralComplexToBoolean: {
13245 bool BoolResult;
13246 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
13247 return false;
13248 uint64_t IntResult = BoolResult;
13249 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
13250 IntResult = (uint64_t)-1;
13251 return Success(IntResult, E);
13252 }
13253
13254 case CK_FixedPointToIntegral: {
13255 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SrcType));
13256 if (!EvaluateFixedPoint(SubExpr, Src, Info))
13257 return false;
13258 bool Overflowed;
13259 llvm::APSInt Result = Src.convertToInt(
13260 Info.Ctx.getIntWidth(DestType),
13261 DestType->isSignedIntegerOrEnumerationType(), &Overflowed);
13262 if (Overflowed && !HandleOverflow(Info, E, Result, DestType))
13263 return false;
13264 return Success(Result, E);
13265 }
13266
13267 case CK_FixedPointToBoolean: {
13268 // Unsigned padding does not affect this.
13269 APValue Val;
13270 if (!Evaluate(Val, Info, SubExpr))
13271 return false;
13272 return Success(Val.getFixedPoint().getBoolValue(), E);
13273 }
13274
13275 case CK_IntegralCast: {
13276 if (!Visit(SubExpr))
13277 return false;
13278
13279 if (!Result.isInt()) {
13280 // Allow casts of address-of-label differences if they are no-ops
13281 // or narrowing. (The narrowing case isn't actually guaranteed to
13282 // be constant-evaluatable except in some narrow cases which are hard
13283 // to detect here. We let it through on the assumption the user knows
13284 // what they are doing.)
13285 if (Result.isAddrLabelDiff())
13286 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
13287 // Only allow casts of lvalues if they are lossless.
13288 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
13289 }
13290
13291 return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
13292 Result.getInt()), E);
13293 }
13294
13295 case CK_PointerToIntegral: {
13296 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
13297
13298 LValue LV;
13299 if (!EvaluatePointer(SubExpr, LV, Info))
13300 return false;
13301
13302 if (LV.getLValueBase()) {
13303 // Only allow based lvalue casts if they are lossless.
13304 // FIXME: Allow a larger integer size than the pointer size, and allow
13305 // narrowing back down to pointer width in subsequent integral casts.
13306 // FIXME: Check integer type's active bits, not its type size.
13307 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
13308 return Error(E);
13309
13310 LV.Designator.setInvalid();
13311 LV.moveInto(Result);
13312 return true;
13313 }
13314
13315 APSInt AsInt;
13316 APValue V;
13317 LV.moveInto(V);
13318 if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx))
13319 llvm_unreachable("Can't cast this!")__builtin_unreachable();
13320
13321 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
13322 }
13323
13324 case CK_IntegralComplexToReal: {
13325 ComplexValue C;
13326 if (!EvaluateComplex(SubExpr, C, Info))
13327 return false;
13328 return Success(C.getComplexIntReal(), E);
13329 }
13330
13331 case CK_FloatingToIntegral: {
13332 APFloat F(0.0);
13333 if (!EvaluateFloat(SubExpr, F, Info))
13334 return false;
13335
13336 APSInt Value;
13337 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
13338 return false;
13339 return Success(Value, E);
13340 }
13341 }
13342
13343 llvm_unreachable("unknown cast resulting in integral value")__builtin_unreachable();
13344}
13345
13346bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
13347 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13348 ComplexValue LV;
13349 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
13350 return false;
13351 if (!LV.isComplexInt())
13352 return Error(E);
13353 return Success(LV.getComplexIntReal(), E);
13354 }
13355
13356 return Visit(E->getSubExpr());
13357}
13358
13359bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
13360 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
13361 ComplexValue LV;
13362 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
13363 return false;
13364 if (!LV.isComplexInt())
13365 return Error(E);
13366 return Success(LV.getComplexIntImag(), E);
13367 }
13368
13369 VisitIgnoredValue(E->getSubExpr());
13370 return Success(0, E);
13371}
13372
13373bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
13374 return Success(E->getPackLength(), E);
13375}
13376
13377bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
13378 return Success(E->getValue(), E);
13379}
13380
13381bool IntExprEvaluator::VisitConceptSpecializationExpr(
13382 const ConceptSpecializationExpr *E) {
13383 return Success(E->isSatisfied(), E);
13384}
13385
13386bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) {
13387 return Success(E->isSatisfied(), E);
13388}
13389
13390bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13391 switch (E->getOpcode()) {
13392 default:
13393 // Invalid unary operators
13394 return Error(E);
13395 case UO_Plus:
13396 // The result is just the value.
13397 return Visit(E->getSubExpr());
13398 case UO_Minus: {
13399 if (!Visit(E->getSubExpr())) return false;
13400 if (!Result.isFixedPoint())
13401 return Error(E);
13402 bool Overflowed;
13403 APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed);
13404 if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType()))
13405 return false;
13406 return Success(Negated, E);
13407 }
13408 case UO_LNot: {
13409 bool bres;
13410 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
13411 return false;
13412 return Success(!bres, E);
13413 }
13414 }
13415}
13416
13417bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
13418 const Expr *SubExpr = E->getSubExpr();
13419 QualType DestType = E->getType();
13420 assert(DestType->isFixedPointType() &&((void)0)
13421 "Expected destination type to be a fixed point type")((void)0);
13422 auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType);
13423
13424 switch (E->getCastKind()) {
13425 case CK_FixedPointCast: {
13426 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
13427 if (!EvaluateFixedPoint(SubExpr, Src, Info))
13428 return false;
13429 bool Overflowed;
13430 APFixedPoint Result = Src.convert(DestFXSema, &Overflowed);
13431 if (Overflowed) {
13432 if (Info.checkingForUndefinedBehavior())
13433 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13434 diag::warn_fixedpoint_constant_overflow)
13435 << Result.toString() << E->getType();
13436 if (!HandleOverflow(Info, E, Result, E->getType()))
13437 return false;
13438 }
13439 return Success(Result, E);
13440 }
13441 case CK_IntegralToFixedPoint: {
13442 APSInt Src;
13443 if (!EvaluateInteger(SubExpr, Src, Info))
13444 return false;
13445
13446 bool Overflowed;
13447 APFixedPoint IntResult = APFixedPoint::getFromIntValue(
13448 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);
13449
13450 if (Overflowed) {
13451 if (Info.checkingForUndefinedBehavior())
13452 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13453 diag::warn_fixedpoint_constant_overflow)
13454 << IntResult.toString() << E->getType();
13455 if (!HandleOverflow(Info, E, IntResult, E->getType()))
13456 return false;
13457 }
13458
13459 return Success(IntResult, E);
13460 }
13461 case CK_FloatingToFixedPoint: {
13462 APFloat Src(0.0);
13463 if (!EvaluateFloat(SubExpr, Src, Info))
13464 return false;
13465
13466 bool Overflowed;
13467 APFixedPoint Result = APFixedPoint::getFromFloatValue(
13468 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);
13469
13470 if (Overflowed) {
13471 if (Info.checkingForUndefinedBehavior())
13472 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13473 diag::warn_fixedpoint_constant_overflow)
13474 << Result.toString() << E->getType();
13475 if (!HandleOverflow(Info, E, Result, E->getType()))
13476 return false;
13477 }
13478
13479 return Success(Result, E);
13480 }
13481 case CK_NoOp:
13482 case CK_LValueToRValue:
13483 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13484 default:
13485 return Error(E);
13486 }
13487}
13488
13489bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13490 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
13491 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13492
13493 const Expr *LHS = E->getLHS();
13494 const Expr *RHS = E->getRHS();
13495 FixedPointSemantics ResultFXSema =
13496 Info.Ctx.getFixedPointSemantics(E->getType());
13497
13498 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType()));
13499 if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info))
13500 return false;
13501 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType()));
13502 if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info))
13503 return false;
13504
13505 bool OpOverflow = false, ConversionOverflow = false;
13506 APFixedPoint Result(LHSFX.getSemantics());
13507 switch (E->getOpcode()) {
13508 case BO_Add: {
13509 Result = LHSFX.add(RHSFX, &OpOverflow)
13510 .convert(ResultFXSema, &ConversionOverflow);
13511 break;
13512 }
13513 case BO_Sub: {
13514 Result = LHSFX.sub(RHSFX, &OpOverflow)
13515 .convert(ResultFXSema, &ConversionOverflow);
13516 break;
13517 }
13518 case BO_Mul: {
13519 Result = LHSFX.mul(RHSFX, &OpOverflow)
13520 .convert(ResultFXSema, &ConversionOverflow);
13521 break;
13522 }
13523 case BO_Div: {
13524 if (RHSFX.getValue() == 0) {
13525 Info.FFDiag(E, diag::note_expr_divide_by_zero);
13526 return false;
13527 }
13528 Result = LHSFX.div(RHSFX, &OpOverflow)
13529 .convert(ResultFXSema, &ConversionOverflow);
13530 break;
13531 }
13532 case BO_Shl:
13533 case BO_Shr: {
13534 FixedPointSemantics LHSSema = LHSFX.getSemantics();
13535 llvm::APSInt RHSVal = RHSFX.getValue();
13536
13537 unsigned ShiftBW =
13538 LHSSema.getWidth() - (unsigned)LHSSema.hasUnsignedPadding();
13539 unsigned Amt = RHSVal.getLimitedValue(ShiftBW - 1);
13540 // Embedded-C 4.1.6.2.2:
13541 // The right operand must be nonnegative and less than the total number
13542 // of (nonpadding) bits of the fixed-point operand ...
13543 if (RHSVal.isNegative())
13544 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHSVal;
13545 else if (Amt != RHSVal)
13546 Info.CCEDiag(E, diag::note_constexpr_large_shift)
13547 << RHSVal << E->getType() << ShiftBW;
13548
13549 if (E->getOpcode() == BO_Shl)
13550 Result = LHSFX.shl(Amt, &OpOverflow);
13551 else
13552 Result = LHSFX.shr(Amt, &OpOverflow);
13553 break;
13554 }
13555 default:
13556 return false;
13557 }
13558 if (OpOverflow || ConversionOverflow) {
13559 if (Info.checkingForUndefinedBehavior())
13560 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13561 diag::warn_fixedpoint_constant_overflow)
13562 << Result.toString() << E->getType();
13563 if (!HandleOverflow(Info, E, Result, E->getType()))
13564 return false;
13565 }
13566 return Success(Result, E);
13567}
13568
13569//===----------------------------------------------------------------------===//
13570// Float Evaluation
13571//===----------------------------------------------------------------------===//
13572
13573namespace {
13574class FloatExprEvaluator
13575 : public ExprEvaluatorBase<FloatExprEvaluator> {
13576 APFloat &Result;
13577public:
13578 FloatExprEvaluator(EvalInfo &info, APFloat &result)
13579 : ExprEvaluatorBaseTy(info), Result(result) {}
13580
13581 bool Success(const APValue &V, const Expr *e) {
13582 Result = V.getFloat();
13583 return true;
13584 }
13585
13586 bool ZeroInitialization(const Expr *E) {
13587 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
13588 return true;
13589 }
13590
13591 bool VisitCallExpr(const CallExpr *E);
13592
13593 bool VisitUnaryOperator(const UnaryOperator *E);
13594 bool VisitBinaryOperator(const BinaryOperator *E);
13595 bool VisitFloatingLiteral(const FloatingLiteral *E);
13596 bool VisitCastExpr(const CastExpr *E);
13597
13598 bool VisitUnaryReal(const UnaryOperator *E);
13599 bool VisitUnaryImag(const UnaryOperator *E);
13600
13601 // FIXME: Missing: array subscript of vector, member of vector
13602};
13603} // end anonymous namespace
13604
13605static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
13606 assert(!E->isValueDependent())((void)0);
13607 assert(E->isPRValue() && E->getType()->isRealFloatingType())((void)0);
13608 return FloatExprEvaluator(Info, Result).Visit(E);
13609}
13610
13611static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
13612 QualType ResultTy,
13613 const Expr *Arg,
13614 bool SNaN,
13615 llvm::APFloat &Result) {
13616 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
13617 if (!S) return false;
13618
13619 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
13620
13621 llvm::APInt fill;
13622
13623 // Treat empty strings as if they were zero.
13624 if (S->getString().empty())
13625 fill = llvm::APInt(32, 0);
13626 else if (S->getString().getAsInteger(0, fill))
13627 return false;
13628
13629 if (Context.getTargetInfo().isNan2008()) {
13630 if (SNaN)
13631 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
13632 else
13633 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
13634 } else {
13635 // Prior to IEEE 754-2008, architectures were allowed to choose whether
13636 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
13637 // a different encoding to what became a standard in 2008, and for pre-
13638 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
13639 // sNaN. This is now known as "legacy NaN" encoding.
13640 if (SNaN)
13641 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
13642 else
13643 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
13644 }
13645
13646 return true;
13647}
13648
13649bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
13650 switch (E->getBuiltinCallee()) {
13651 default:
13652 return ExprEvaluatorBaseTy::VisitCallExpr(E);
13653
13654 case Builtin::BI__builtin_huge_val:
13655 case Builtin::BI__builtin_huge_valf:
13656 case Builtin::BI__builtin_huge_vall:
13657 case Builtin::BI__builtin_huge_valf128:
13658 case Builtin::BI__builtin_inf:
13659 case Builtin::BI__builtin_inff:
13660 case Builtin::BI__builtin_infl:
13661 case Builtin::BI__builtin_inff128: {
13662 const llvm::fltSemantics &Sem =
13663 Info.Ctx.getFloatTypeSemantics(E->getType());
13664 Result = llvm::APFloat::getInf(Sem);
13665 return true;
13666 }
13667
13668 case Builtin::BI__builtin_nans:
13669 case Builtin::BI__builtin_nansf:
13670 case Builtin::BI__builtin_nansl:
13671 case Builtin::BI__builtin_nansf128:
13672 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
13673 true, Result))
13674 return Error(E);
13675 return true;
13676
13677 case Builtin::BI__builtin_nan:
13678 case Builtin::BI__builtin_nanf:
13679 case Builtin::BI__builtin_nanl:
13680 case Builtin::BI__builtin_nanf128:
13681 // If this is __builtin_nan() turn this into a nan, otherwise we
13682 // can't constant fold it.
13683 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
13684 false, Result))
13685 return Error(E);
13686 return true;
13687
13688 case Builtin::BI__builtin_fabs:
13689 case Builtin::BI__builtin_fabsf:
13690 case Builtin::BI__builtin_fabsl:
13691 case Builtin::BI__builtin_fabsf128:
13692 // The C standard says "fabs raises no floating-point exceptions,
13693 // even if x is a signaling NaN. The returned value is independent of
13694 // the current rounding direction mode." Therefore constant folding can
13695 // proceed without regard to the floating point settings.
13696 // Reference, WG14 N2478 F.10.4.3
13697 if (!EvaluateFloat(E->getArg(0), Result, Info))
13698 return false;
13699
13700 if (Result.isNegative())
13701 Result.changeSign();
13702 return true;
13703
13704 case Builtin::BI__arithmetic_fence:
13705 return EvaluateFloat(E->getArg(0), Result, Info);
13706
13707 // FIXME: Builtin::BI__builtin_powi
13708 // FIXME: Builtin::BI__builtin_powif
13709 // FIXME: Builtin::BI__builtin_powil
13710
13711 case Builtin::BI__builtin_copysign:
13712 case Builtin::BI__builtin_copysignf:
13713 case Builtin::BI__builtin_copysignl:
13714 case Builtin::BI__builtin_copysignf128: {
13715 APFloat RHS(0.);
13716 if (!EvaluateFloat(E->getArg(0), Result, Info) ||
13717 !EvaluateFloat(E->getArg(1), RHS, Info))
13718 return false;
13719 Result.copySign(RHS);
13720 return true;
13721 }
13722 }
13723}
13724
13725bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
13726 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13727 ComplexValue CV;
13728 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
13729 return false;
13730 Result = CV.FloatReal;
13731 return true;
13732 }
13733
13734 return Visit(E->getSubExpr());
13735}
13736
13737bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
13738 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13739 ComplexValue CV;
13740 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
13741 return false;
13742 Result = CV.FloatImag;
13743 return true;
13744 }
13745
13746 VisitIgnoredValue(E->getSubExpr());
13747 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
13748 Result = llvm::APFloat::getZero(Sem);
13749 return true;
13750}
13751
13752bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13753 switch (E->getOpcode()) {
13754 default: return Error(E);
13755 case UO_Plus:
13756 return EvaluateFloat(E->getSubExpr(), Result, Info);
13757 case UO_Minus:
13758 // In C standard, WG14 N2478 F.3 p4
13759 // "the unary - raises no floating point exceptions,
13760 // even if the operand is signalling."
13761 if (!EvaluateFloat(E->getSubExpr(), Result, Info))
13762 return false;
13763 Result.changeSign();
13764 return true;
13765 }
13766}
13767
13768bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13769 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
13770 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13771
13772 APFloat RHS(0.0);
13773 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
13774 if (!LHSOK && !Info.noteFailure())
13775 return false;
13776 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
13777 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
13778}
13779
13780bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
13781 Result = E->getValue();
13782 return true;
13783}
13784
13785bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
13786 const Expr* SubExpr = E->getSubExpr();
13787
13788 switch (E->getCastKind()) {
13789 default:
13790 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13791
13792 case CK_IntegralToFloating: {
13793 APSInt IntResult;
13794 const FPOptions FPO = E->getFPFeaturesInEffect(
13795 Info.Ctx.getLangOpts());
13796 return EvaluateInteger(SubExpr, IntResult, Info) &&
13797 HandleIntToFloatCast(Info, E, FPO, SubExpr->getType(),
13798 IntResult, E->getType(), Result);
13799 }
13800
13801 case CK_FixedPointToFloating: {
13802 APFixedPoint FixResult(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
13803 if (!EvaluateFixedPoint(SubExpr, FixResult, Info))
13804 return false;
13805 Result =
13806 FixResult.convertToFloat(Info.Ctx.getFloatTypeSemantics(E->getType()));
13807 return true;
13808 }
13809
13810 case CK_FloatingCast: {
13811 if (!Visit(SubExpr))
13812 return false;
13813 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
13814 Result);
13815 }
13816
13817 case CK_FloatingComplexToReal: {
13818 ComplexValue V;
13819 if (!EvaluateComplex(SubExpr, V, Info))
13820 return false;
13821 Result = V.getComplexFloatReal();
13822 return true;
13823 }
13824 }
13825}
13826
13827//===----------------------------------------------------------------------===//
13828// Complex Evaluation (for float and integer)
13829//===----------------------------------------------------------------------===//
13830
13831namespace {
13832class ComplexExprEvaluator
13833 : public ExprEvaluatorBase<ComplexExprEvaluator> {
13834 ComplexValue &Result;
13835
13836public:
13837 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
13838 : ExprEvaluatorBaseTy(info), Result(Result) {}
13839
13840 bool Success(const APValue &V, const Expr *e) {
13841 Result.setFrom(V);
20
Calling 'ComplexValue::setFrom'
13842 return true;
13843 }
13844
13845 bool ZeroInitialization(const Expr *E);
13846
13847 //===--------------------------------------------------------------------===//
13848 // Visitor Methods
13849 //===--------------------------------------------------------------------===//
13850
13851 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
13852 bool VisitCastExpr(const CastExpr *E);
13853 bool VisitBinaryOperator(const BinaryOperator *E);
13854 bool VisitUnaryOperator(const UnaryOperator *E);
13855 bool VisitInitListExpr(const InitListExpr *E);
13856 bool VisitCallExpr(const CallExpr *E);
13857};
13858} // end anonymous namespace
13859
13860static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
13861 EvalInfo &Info) {
13862 assert(!E->isValueDependent())((void)0);
13863 assert(E->isPRValue() && E->getType()->isAnyComplexType())((void)0);
13864 return ComplexExprEvaluator(Info, Result).Visit(E);
13865}
13866
13867bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
13868 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
13869 if (ElemTy->isRealFloatingType()) {
13870 Result.makeComplexFloat();
13871 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
13872 Result.FloatReal = Zero;
13873 Result.FloatImag = Zero;
13874 } else {
13875 Result.makeComplexInt();
13876 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
13877 Result.IntReal = Zero;
13878 Result.IntImag = Zero;
13879 }
13880 return true;
13881}
13882
13883bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
13884 const Expr* SubExpr = E->getSubExpr();
13885
13886 if (SubExpr->getType()->isRealFloatingType()) {
13887 Result.makeComplexFloat();
13888 APFloat &Imag = Result.FloatImag;
13889 if (!EvaluateFloat(SubExpr, Imag, Info))
13890 return false;
13891
13892 Result.FloatReal = APFloat(Imag.getSemantics());
13893 return true;
13894 } else {
13895 assert(SubExpr->getType()->isIntegerType() &&((void)0)
13896 "Unexpected imaginary literal.")((void)0);
13897
13898 Result.makeComplexInt();
13899 APSInt &Imag = Result.IntImag;
13900 if (!EvaluateInteger(SubExpr, Imag, Info))
13901 return false;
13902
13903 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
13904 return true;
13905 }
13906}
13907
13908bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
13909
13910 switch (E->getCastKind()) {
13911 case CK_BitCast:
13912 case CK_BaseToDerived:
13913 case CK_DerivedToBase:
13914 case CK_UncheckedDerivedToBase:
13915 case CK_Dynamic:
13916 case CK_ToUnion:
13917 case CK_ArrayToPointerDecay:
13918 case CK_FunctionToPointerDecay:
13919 case CK_NullToPointer:
13920 case CK_NullToMemberPointer:
13921 case CK_BaseToDerivedMemberPointer:
13922 case CK_DerivedToBaseMemberPointer:
13923 case CK_MemberPointerToBoolean:
13924 case CK_ReinterpretMemberPointer:
13925 case CK_ConstructorConversion:
13926 case CK_IntegralToPointer:
13927 case CK_PointerToIntegral:
13928 case CK_PointerToBoolean:
13929 case CK_ToVoid:
13930 case CK_VectorSplat:
13931 case CK_IntegralCast:
13932 case CK_BooleanToSignedIntegral:
13933 case CK_IntegralToBoolean:
13934 case CK_IntegralToFloating:
13935 case CK_FloatingToIntegral:
13936 case CK_FloatingToBoolean:
13937 case CK_FloatingCast:
13938 case CK_CPointerToObjCPointerCast:
13939 case CK_BlockPointerToObjCPointerCast:
13940 case CK_AnyPointerToBlockPointerCast:
13941 case CK_ObjCObjectLValueCast:
13942 case CK_FloatingComplexToReal:
13943 case CK_FloatingComplexToBoolean:
13944 case CK_IntegralComplexToReal:
13945 case CK_IntegralComplexToBoolean:
13946 case CK_ARCProduceObject:
13947 case CK_ARCConsumeObject:
13948 case CK_ARCReclaimReturnedObject:
13949 case CK_ARCExtendBlockObject:
13950 case CK_CopyAndAutoreleaseBlockObject:
13951 case CK_BuiltinFnToFnPtr:
13952 case CK_ZeroToOCLOpaqueType:
13953 case CK_NonAtomicToAtomic:
13954 case CK_AddressSpaceConversion:
13955 case CK_IntToOCLSampler:
13956 case CK_FloatingToFixedPoint:
13957 case CK_FixedPointToFloating:
13958 case CK_FixedPointCast:
13959 case CK_FixedPointToBoolean:
13960 case CK_FixedPointToIntegral:
13961 case CK_IntegralToFixedPoint:
13962 case CK_MatrixCast:
13963 llvm_unreachable("invalid cast kind for complex value")__builtin_unreachable();
13964
13965 case CK_LValueToRValue:
13966 case CK_AtomicToNonAtomic:
13967 case CK_NoOp:
13968 case CK_LValueToRValueBitCast:
13969 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13970
13971 case CK_Dependent:
13972 case CK_LValueBitCast:
13973 case CK_UserDefinedConversion:
13974 return Error(E);
13975
13976 case CK_FloatingRealToComplex: {
13977 APFloat &Real = Result.FloatReal;
13978 if (!EvaluateFloat(E->getSubExpr(), Real, Info))
13979 return false;
13980
13981 Result.makeComplexFloat();
13982 Result.FloatImag = APFloat(Real.getSemantics());
13983 return true;
13984 }
13985
13986 case CK_FloatingComplexCast: {
13987 if (!Visit(E->getSubExpr()))
13988 return false;
13989
13990 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13991 QualType From
13992 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13993
13994 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
13995 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
13996 }
13997
13998 case CK_FloatingComplexToIntegralComplex: {
13999 if (!Visit(E->getSubExpr()))
14000 return false;
14001
14002 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14003 QualType From
14004 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14005 Result.makeComplexInt();
14006 return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
14007 To, Result.IntReal) &&
14008 HandleFloatToIntCast(Info, E, From, Result.FloatImag,
14009 To, Result.IntImag);
14010 }
14011
14012 case CK_IntegralRealToComplex: {
14013 APSInt &Real = Result.IntReal;
14014 if (!EvaluateInteger(E->getSubExpr(), Real, Info))
14015 return false;
14016
14017 Result.makeComplexInt();
14018 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
14019 return true;
14020 }
14021
14022 case CK_IntegralComplexCast: {
14023 if (!Visit(E->getSubExpr()))
14024 return false;
14025
14026 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14027 QualType From
14028 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14029
14030 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
14031 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
14032 return true;
14033 }
14034
14035 case CK_IntegralComplexToFloatingComplex: {
14036 if (!Visit(E->getSubExpr()))
14037 return false;
14038
14039 const FPOptions FPO = E->getFPFeaturesInEffect(
14040 Info.Ctx.getLangOpts());
14041 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14042 QualType From
14043 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14044 Result.makeComplexFloat();
14045 return HandleIntToFloatCast(Info, E, FPO, From, Result.IntReal,
14046 To, Result.FloatReal) &&
14047 HandleIntToFloatCast(Info, E, FPO, From, Result.IntImag,
14048 To, Result.FloatImag);
14049 }
14050 }
14051
14052 llvm_unreachable("unknown cast resulting in complex value")__builtin_unreachable();
14053}
14054
14055bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
14056 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
14057 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
14058
14059 // Track whether the LHS or RHS is real at the type system level. When this is
14060 // the case we can simplify our evaluation strategy.
14061 bool LHSReal = false, RHSReal = false;
14062
14063 bool LHSOK;
14064 if (E->getLHS()->getType()->isRealFloatingType()) {
14065 LHSReal = true;
14066 APFloat &Real = Result.FloatReal;
14067 LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
14068 if (LHSOK) {
14069 Result.makeComplexFloat();
14070 Result.FloatImag = APFloat(Real.getSemantics());
14071 }
14072 } else {
14073 LHSOK = Visit(E->getLHS());
14074 }
14075 if (!LHSOK && !Info.noteFailure())
14076 return false;
14077
14078 ComplexValue RHS;
14079 if (E->getRHS()->getType()->isRealFloatingType()) {
14080 RHSReal = true;
14081 APFloat &Real = RHS.FloatReal;
14082 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
14083 return false;
14084 RHS.makeComplexFloat();
14085 RHS.FloatImag = APFloat(Real.getSemantics());
14086 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
14087 return false;
14088
14089 assert(!(LHSReal && RHSReal) &&((void)0)
14090 "Cannot have both operands of a complex operation be real.")((void)0);
14091 switch (E->getOpcode()) {
14092 default: return Error(E);
14093 case BO_Add:
14094 if (Result.isComplexFloat()) {
14095 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
14096 APFloat::rmNearestTiesToEven);
14097 if (LHSReal)
14098 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
14099 else if (!RHSReal)
14100 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
14101 APFloat::rmNearestTiesToEven);
14102 } else {
14103 Result.getComplexIntReal() += RHS.getComplexIntReal();
14104 Result.getComplexIntImag() += RHS.getComplexIntImag();
14105 }
14106 break;
14107 case BO_Sub:
14108 if (Result.isComplexFloat()) {
14109 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
14110 APFloat::rmNearestTiesToEven);
14111 if (LHSReal) {
14112 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
14113 Result.getComplexFloatImag().changeSign();
14114 } else if (!RHSReal) {
14115 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
14116 APFloat::rmNearestTiesToEven);
14117 }
14118 } else {
14119 Result.getComplexIntReal() -= RHS.getComplexIntReal();
14120 Result.getComplexIntImag() -= RHS.getComplexIntImag();
14121 }
14122 break;
14123 case BO_Mul:
14124 if (Result.isComplexFloat()) {
14125 // This is an implementation of complex multiplication according to the
14126 // constraints laid out in C11 Annex G. The implementation uses the
14127 // following naming scheme:
14128 // (a + ib) * (c + id)
14129 ComplexValue LHS = Result;
14130 APFloat &A = LHS.getComplexFloatReal();
14131 APFloat &B = LHS.getComplexFloatImag();
14132 APFloat &C = RHS.getComplexFloatReal();
14133 APFloat &D = RHS.getComplexFloatImag();
14134 APFloat &ResR = Result.getComplexFloatReal();
14135 APFloat &ResI = Result.getComplexFloatImag();
14136 if (LHSReal) {
14137 assert(!RHSReal && "Cannot have two real operands for a complex op!")((void)0);
14138 ResR = A * C;
14139 ResI = A * D;
14140 } else if (RHSReal) {
14141 ResR = C * A;
14142 ResI = C * B;
14143 } else {
14144 // In the fully general case, we need to handle NaNs and infinities
14145 // robustly.
14146 APFloat AC = A * C;
14147 APFloat BD = B * D;
14148 APFloat AD = A * D;
14149 APFloat BC = B * C;
14150 ResR = AC - BD;
14151 ResI = AD + BC;
14152 if (ResR.isNaN() && ResI.isNaN()) {
14153 bool Recalc = false;
14154 if (A.isInfinity() || B.isInfinity()) {
14155 A = APFloat::copySign(
14156 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
14157 B = APFloat::copySign(
14158 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
14159 if (C.isNaN())
14160 C = APFloat::copySign(APFloat(C.getSemantics()), C);
14161 if (D.isNaN())
14162 D = APFloat::copySign(APFloat(D.getSemantics()), D);
14163 Recalc = true;
14164 }
14165 if (C.isInfinity() || D.isInfinity()) {
14166 C = APFloat::copySign(
14167 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
14168 D = APFloat::copySign(
14169 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
14170 if (A.isNaN())
14171 A = APFloat::copySign(APFloat(A.getSemantics()), A);
14172 if (B.isNaN())
14173 B = APFloat::copySign(APFloat(B.getSemantics()), B);
14174 Recalc = true;
14175 }
14176 if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
14177 AD.isInfinity() || BC.isInfinity())) {
14178 if (A.isNaN())
14179 A = APFloat::copySign(APFloat(A.getSemantics()), A);
14180 if (B.isNaN())
14181 B = APFloat::copySign(APFloat(B.getSemantics()), B);
14182 if (C.isNaN())
14183 C = APFloat::copySign(APFloat(C.getSemantics()), C);
14184 if (D.isNaN())
14185 D = APFloat::copySign(APFloat(D.getSemantics()), D);
14186 Recalc = true;
14187 }
14188 if (Recalc) {
14189 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
14190 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
14191 }
14192 }
14193 }
14194 } else {
14195 ComplexValue LHS = Result;
14196 Result.getComplexIntReal() =
14197 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
14198 LHS.getComplexIntImag() * RHS.getComplexIntImag());
14199 Result.getComplexIntImag() =
14200 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
14201 LHS.getComplexIntImag() * RHS.getComplexIntReal());
14202 }
14203 break;
14204 case BO_Div:
14205 if (Result.isComplexFloat()) {
14206 // This is an implementation of complex division according to the
14207 // constraints laid out in C11 Annex G. The implementation uses the
14208 // following naming scheme:
14209 // (a + ib) / (c + id)
14210 ComplexValue LHS = Result;
14211 APFloat &A = LHS.getComplexFloatReal();
14212 APFloat &B = LHS.getComplexFloatImag();
14213 APFloat &C = RHS.getComplexFloatReal();
14214 APFloat &D = RHS.getComplexFloatImag();
14215 APFloat &ResR = Result.getComplexFloatReal();
14216 APFloat &ResI = Result.getComplexFloatImag();
14217 if (RHSReal) {
14218 ResR = A / C;
14219 ResI = B / C;
14220 } else {
14221 if (LHSReal) {
14222 // No real optimizations we can do here, stub out with zero.
14223 B = APFloat::getZero(A.getSemantics());
14224 }
14225 int DenomLogB = 0;
14226 APFloat MaxCD = maxnum(abs(C), abs(D));
14227 if (MaxCD.isFinite()) {
14228 DenomLogB = ilogb(MaxCD);
14229 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
14230 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
14231 }
14232 APFloat Denom = C * C + D * D;
14233 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
14234 APFloat::rmNearestTiesToEven);
14235 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
14236 APFloat::rmNearestTiesToEven);
14237 if (ResR.isNaN() && ResI.isNaN()) {
14238 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
14239 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
14240 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
14241 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
14242 D.isFinite()) {
14243 A = APFloat::copySign(
14244 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
14245 B = APFloat::copySign(
14246 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
14247 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
14248 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
14249 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
14250 C = APFloat::copySign(
14251 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
14252 D = APFloat::copySign(
14253 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
14254 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
14255 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
14256 }
14257 }
14258 }
14259 } else {
14260 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
14261 return Error(E, diag::note_expr_divide_by_zero);
14262
14263 ComplexValue LHS = Result;
14264 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
14265 RHS.getComplexIntImag() * RHS.getComplexIntImag();
14266 Result.getComplexIntReal() =
14267 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
14268 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
14269 Result.getComplexIntImag() =
14270 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
14271 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
14272 }
14273 break;
14274 }
14275
14276 return true;
14277}
14278
14279bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
14280 // Get the operand value into 'Result'.
14281 if (!Visit(E->getSubExpr()))
14282 return false;
14283
14284 switch (E->getOpcode()) {
14285 default:
14286 return Error(E);
14287 case UO_Extension:
14288 return true;
14289 case UO_Plus:
14290 // The result is always just the subexpr.
14291 return true;
14292 case UO_Minus:
14293 if (Result.isComplexFloat()) {
14294 Result.getComplexFloatReal().changeSign();
14295 Result.getComplexFloatImag().changeSign();
14296 }
14297 else {
14298 Result.getComplexIntReal() = -Result.getComplexIntReal();
14299 Result.getComplexIntImag() = -Result.getComplexIntImag();
14300 }
14301 return true;
14302 case UO_Not:
14303 if (Result.isComplexFloat())
14304 Result.getComplexFloatImag().changeSign();
14305 else
14306 Result.getComplexIntImag() = -Result.getComplexIntImag();
14307 return true;
14308 }
14309}
14310
14311bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
14312 if (E->getNumInits() == 2) {
14313 if (E->getType()->isComplexType()) {
14314 Result.makeComplexFloat();
14315 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
14316 return false;
14317 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
14318 return false;
14319 } else {
14320 Result.makeComplexInt();
14321 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
14322 return false;
14323 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
14324 return false;
14325 }
14326 return true;
14327 }
14328 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
14329}
14330
14331bool ComplexExprEvaluator::VisitCallExpr(const CallExpr *E) {
14332 switch (E->getBuiltinCallee()) {
1
Control jumps to the 'default' case at line 14341
14333 case Builtin::BI__builtin_complex:
14334 Result.makeComplexFloat();
14335 if (!EvaluateFloat(E->getArg(0), Result.FloatReal, Info))
14336 return false;
14337 if (!EvaluateFloat(E->getArg(1), Result.FloatImag, Info))
14338 return false;
14339 return true;
14340
14341 default:
14342 break;
2
Execution continues on line 14345
14343 }
14344
14345 return ExprEvaluatorBaseTy::VisitCallExpr(E);
3
Calling 'ExprEvaluatorBase::VisitCallExpr'
14346}
14347
14348//===----------------------------------------------------------------------===//
14349// Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
14350// implicit conversion.
14351//===----------------------------------------------------------------------===//
14352
14353namespace {
14354class AtomicExprEvaluator :
14355 public ExprEvaluatorBase<AtomicExprEvaluator> {
14356 const LValue *This;
14357 APValue &Result;
14358public:
14359 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
14360 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
14361
14362 bool Success(const APValue &V, const Expr *E) {
14363 Result = V;
14364 return true;
14365 }
14366
14367 bool ZeroInitialization(const Expr *E) {
14368 ImplicitValueInitExpr VIE(
14369 E->getType()->castAs<AtomicType>()->getValueType());
14370 // For atomic-qualified class (and array) types in C++, initialize the
14371 // _Atomic-wrapped subobject directly, in-place.
14372 return This ? EvaluateInPlace(Result, Info, *This, &VIE)
14373 : Evaluate(Result, Info, &VIE);
14374 }
14375
14376 bool VisitCastExpr(const CastExpr *E) {
14377 switch (E->getCastKind()) {
14378 default:
14379 return ExprEvaluatorBaseTy::VisitCastExpr(E);
14380 case CK_NonAtomicToAtomic:
14381 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
14382 : Evaluate(Result, Info, E->getSubExpr());
14383 }
14384 }
14385};
14386} // end anonymous namespace
14387
14388static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
14389 EvalInfo &Info) {
14390 assert(!E->isValueDependent())((void)0);
14391 assert(E->isPRValue() && E->getType()->isAtomicType())((void)0);
14392 return AtomicExprEvaluator(Info, This, Result).Visit(E);
14393}
14394
14395//===----------------------------------------------------------------------===//
14396// Void expression evaluation, primarily for a cast to void on the LHS of a
14397// comma operator
14398//===----------------------------------------------------------------------===//
14399
14400namespace {
14401class VoidExprEvaluator
14402 : public ExprEvaluatorBase<VoidExprEvaluator> {
14403public:
14404 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
14405
14406 bool Success(const APValue &V, const Expr *e) { return true; }
14407
14408 bool ZeroInitialization(const Expr *E) { return true; }
14409
14410 bool VisitCastExpr(const CastExpr *E) {
14411 switch (E->getCastKind()) {
14412 default:
14413 return ExprEvaluatorBaseTy::VisitCastExpr(E);
14414 case CK_ToVoid:
14415 VisitIgnoredValue(E->getSubExpr());
14416 return true;
14417 }
14418 }
14419
14420 bool VisitCallExpr(const CallExpr *E) {
14421 switch (E->getBuiltinCallee()) {
14422 case Builtin::BI__assume:
14423 case Builtin::BI__builtin_assume:
14424 // The argument is not evaluated!
14425 return true;
14426
14427 case Builtin::BI__builtin_operator_delete:
14428 return HandleOperatorDeleteCall(Info, E);
14429
14430 default:
14431 break;
14432 }
14433
14434 return ExprEvaluatorBaseTy::VisitCallExpr(E);
14435 }
14436
14437 bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
14438};
14439} // end anonymous namespace
14440
14441bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
14442 // We cannot speculatively evaluate a delete expression.
14443 if (Info.SpeculativeEvaluationDepth)
14444 return false;
14445
14446 FunctionDecl *OperatorDelete = E->getOperatorDelete();
14447 if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) {
14448 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
14449 << isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete;
14450 return false;
14451 }
14452
14453 const Expr *Arg = E->getArgument();
14454
14455 LValue Pointer;
14456 if (!EvaluatePointer(Arg, Pointer, Info))
14457 return false;
14458 if (Pointer.Designator.Invalid)
14459 return false;
14460
14461 // Deleting a null pointer has no effect.
14462 if (Pointer.isNullPointer()) {
14463 // This is the only case where we need to produce an extension warning:
14464 // the only other way we can succeed is if we find a dynamic allocation,
14465 // and we will have warned when we allocated it in that case.
14466 if (!Info.getLangOpts().CPlusPlus20)
14467 Info.CCEDiag(E, diag::note_constexpr_new);
14468 return true;
14469 }
14470
14471 Optional<DynAlloc *> Alloc = CheckDeleteKind(
14472 Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New);
14473 if (!Alloc)
14474 return false;
14475 QualType AllocType = Pointer.Base.getDynamicAllocType();
14476
14477 // For the non-array case, the designator must be empty if the static type
14478 // does not have a virtual destructor.
14479 if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 &&
14480 !hasVirtualDestructor(Arg->getType()->getPointeeType())) {
14481 Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor)
14482 << Arg->getType()->getPointeeType() << AllocType;
14483 return false;
14484 }
14485
14486 // For a class type with a virtual destructor, the selected operator delete
14487 // is the one looked up when building the destructor.
14488 if (!E->isArrayForm() && !E->isGlobalDelete()) {
14489 const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(AllocType);
14490 if (VirtualDelete &&
14491 !VirtualDelete->isReplaceableGlobalAllocationFunction()) {
14492 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
14493 << isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete;
14494 return false;
14495 }
14496 }
14497
14498 if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(),
14499 (*Alloc)->Value, AllocType))
14500 return false;
14501
14502 if (!Info.HeapAllocs.erase(Pointer.Base.dyn_cast<DynamicAllocLValue>())) {
14503 // The element was already erased. This means the destructor call also
14504 // deleted the object.
14505 // FIXME: This probably results in undefined behavior before we get this
14506 // far, and should be diagnosed elsewhere first.
14507 Info.FFDiag(E, diag::note_constexpr_double_delete);
14508 return false;
14509 }
14510
14511 return true;
14512}
14513
14514static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
14515 assert(!E->isValueDependent())((void)0);
14516 assert(E->isPRValue() && E->getType()->isVoidType())((void)0);
14517 return VoidExprEvaluator(Info).Visit(E);
14518}
14519
14520//===----------------------------------------------------------------------===//
14521// Top level Expr::EvaluateAsRValue method.
14522//===----------------------------------------------------------------------===//
14523
14524static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
14525 assert(!E->isValueDependent())((void)0);
14526 // In C, function designators are not lvalues, but we evaluate them as if they
14527 // are.
14528 QualType T = E->getType();
14529 if (E->isGLValue() || T->isFunctionType()) {
14530 LValue LV;
14531 if (!EvaluateLValue(E, LV, Info))
14532 return false;
14533 LV.moveInto(Result);
14534 } else if (T->isVectorType()) {
14535 if (!EvaluateVector(E, Result, Info))
14536 return false;
14537 } else if (T->isIntegralOrEnumerationType()) {
14538 if (!IntExprEvaluator(Info, Result).Visit(E))
14539 return false;
14540 } else if (T->hasPointerRepresentation()) {
14541 LValue LV;
14542 if (!EvaluatePointer(E, LV, Info))
14543 return false;
14544 LV.moveInto(Result);
14545 } else if (T->isRealFloatingType()) {
14546 llvm::APFloat F(0.0);
14547 if (!EvaluateFloat(E, F, Info))
14548 return false;
14549 Result = APValue(F);
14550 } else if (T->isAnyComplexType()) {
14551 ComplexValue C;
14552 if (!EvaluateComplex(E, C, Info))
14553 return false;
14554 C.moveInto(Result);
14555 } else if (T->isFixedPointType()) {
14556 if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false;
14557 } else if (T->isMemberPointerType()) {
14558 MemberPtr P;
14559 if (!EvaluateMemberPointer(E, P, Info))
14560 return false;
14561 P.moveInto(Result);
14562 return true;
14563 } else if (T->isArrayType()) {
14564 LValue LV;
14565 APValue &Value =
14566 Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV);
14567 if (!EvaluateArray(E, LV, Value, Info))
14568 return false;
14569 Result = Value;
14570 } else if (T->isRecordType()) {
14571 LValue LV;
14572 APValue &Value =
14573 Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV);
14574 if (!EvaluateRecord(E, LV, Value, Info))
14575 return false;
14576 Result = Value;
14577 } else if (T->isVoidType()) {
14578 if (!Info.getLangOpts().CPlusPlus11)
14579 Info.CCEDiag(E, diag::note_constexpr_nonliteral)
14580 << E->getType();
14581 if (!EvaluateVoid(E, Info))
14582 return false;
14583 } else if (T->isAtomicType()) {
14584 QualType Unqual = T.getAtomicUnqualifiedType();
14585 if (Unqual->isArrayType() || Unqual->isRecordType()) {
14586 LValue LV;
14587 APValue &Value = Info.CurrentCall->createTemporary(
14588 E, Unqual, ScopeKind::FullExpression, LV);
14589 if (!EvaluateAtomic(E, &LV, Value, Info))
14590 return false;
14591 } else {
14592 if (!EvaluateAtomic(E, nullptr, Result, Info))
14593 return false;
14594 }
14595 } else if (Info.getLangOpts().CPlusPlus11) {
14596 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
14597 return false;
14598 } else {
14599 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
14600 return false;
14601 }
14602
14603 return true;
14604}
14605
14606/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
14607/// cases, the in-place evaluation is essential, since later initializers for
14608/// an object can indirectly refer to subobjects which were initialized earlier.
14609static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
14610 const Expr *E, bool AllowNonLiteralTypes) {
14611 assert(!E->isValueDependent())((void)0);
14612
14613 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
14614 return false;
14615
14616 if (E->isPRValue()) {
14617 // Evaluate arrays and record types in-place, so that later initializers can
14618 // refer to earlier-initialized members of the object.
14619 QualType T = E->getType();
14620 if (T->isArrayType())
14621 return EvaluateArray(E, This, Result, Info);
14622 else if (T->isRecordType())
14623 return EvaluateRecord(E, This, Result, Info);
14624 else if (T->isAtomicType()) {
14625 QualType Unqual = T.getAtomicUnqualifiedType();
14626 if (Unqual->isArrayType() || Unqual->isRecordType())
14627 return EvaluateAtomic(E, &This, Result, Info);
14628 }
14629 }
14630
14631 // For any other type, in-place evaluation is unimportant.
14632 return Evaluate(Result, Info, E);
14633}
14634
14635/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
14636/// lvalue-to-rvalue cast if it is an lvalue.
14637static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
14638 assert(!E->isValueDependent())((void)0);
14639 if (Info.EnableNewConstInterp) {
14640 if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result))
14641 return false;
14642 } else {
14643 if (E->getType().isNull())
14644 return false;
14645
14646 if (!CheckLiteralType(Info, E))
14647 return false;
14648
14649 if (!::Evaluate(Result, Info, E))
14650 return false;
14651
14652 if (E->isGLValue()) {
14653 LValue LV;
14654 LV.setFrom(Info.Ctx, Result);
14655 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
14656 return false;
14657 }
14658 }
14659
14660 // Check this core constant expression is a constant expression.
14661 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
14662 ConstantExprKind::Normal) &&
14663 CheckMemoryLeaks(Info);
14664}
14665
14666static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
14667 const ASTContext &Ctx, bool &IsConst) {
14668 // Fast-path evaluations of integer literals, since we sometimes see files
14669 // containing vast quantities of these.
14670 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
14671 Result.Val = APValue(APSInt(L->getValue(),
14672 L->getType()->isUnsignedIntegerType()));
14673 IsConst = true;
14674 return true;
14675 }
14676
14677 // This case should be rare, but we need to check it before we check on
14678 // the type below.
14679 if (Exp->getType().isNull()) {
14680 IsConst = false;
14681 return true;
14682 }
14683
14684 // FIXME: Evaluating values of large array and record types can cause
14685 // performance problems. Only do so in C++11 for now.
14686 if (Exp->isPRValue() &&
14687 (Exp->getType()->isArrayType() || Exp->getType()->isRecordType()) &&
14688 !Ctx.getLangOpts().CPlusPlus11) {
14689 IsConst = false;
14690 return true;
14691 }
14692 return false;
14693}
14694
14695static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
14696 Expr::SideEffectsKind SEK) {
14697 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
14698 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
14699}
14700
14701static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result,
14702 const ASTContext &Ctx, EvalInfo &Info) {
14703 assert(!E->isValueDependent())((void)0);
14704 bool IsConst;
14705 if (FastEvaluateAsRValue(E, Result, Ctx, IsConst))
14706 return IsConst;
14707
14708 return EvaluateAsRValue(Info, E, Result.Val);
14709}
14710
14711static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
14712 const ASTContext &Ctx,
14713 Expr::SideEffectsKind AllowSideEffects,
14714 EvalInfo &Info) {
14715 assert(!E->isValueDependent())((void)0);
14716 if (!E->getType()->isIntegralOrEnumerationType())
14717 return false;
14718
14719 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info) ||
14720 !ExprResult.Val.isInt() ||
14721 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14722 return false;
14723
14724 return true;
14725}
14726
14727static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
14728 const ASTContext &Ctx,
14729 Expr::SideEffectsKind AllowSideEffects,
14730 EvalInfo &Info) {
14731 assert(!E->isValueDependent())((void)0);
14732 if (!E->getType()->isFixedPointType())
14733 return false;
14734
14735 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info))
14736 return false;
14737
14738 if (!ExprResult.Val.isFixedPoint() ||
14739 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14740 return false;
14741
14742 return true;
14743}
14744
14745/// EvaluateAsRValue - Return true if this is a constant which we can fold using
14746/// any crazy technique (that has nothing to do with language standards) that
14747/// we want to. If this function returns true, it returns the folded constant
14748/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
14749/// will be applied to the result.
14750bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
14751 bool InConstantContext) const {
14752 assert(!isValueDependent() &&((void)0)
14753 "Expression evaluator can't be called on a dependent expression.")((void)0);
14754 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14755 Info.InConstantContext = InConstantContext;
14756 return ::EvaluateAsRValue(this, Result, Ctx, Info);
14757}
14758
14759bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
14760 bool InConstantContext) const {
14761 assert(!isValueDependent() &&((void)0)
14762 "Expression evaluator can't be called on a dependent expression.")((void)0);
14763 EvalResult Scratch;
14764 return EvaluateAsRValue(Scratch, Ctx, InConstantContext) &&
14765 HandleConversionToBool(Scratch.Val, Result);
14766}
14767
14768bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
14769 SideEffectsKind AllowSideEffects,
14770 bool InConstantContext) const {
14771 assert(!isValueDependent() &&((void)0)
14772 "Expression evaluator can't be called on a dependent expression.")((void)0);
14773 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14774 Info.InConstantContext = InConstantContext;
14775 return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info);
14776}
14777
14778bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
14779 SideEffectsKind AllowSideEffects,
14780 bool InConstantContext) const {
14781 assert(!isValueDependent() &&((void)0)
14782 "Expression evaluator can't be called on a dependent expression.")((void)0);
14783 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14784 Info.InConstantContext = InConstantContext;
14785 return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info);
14786}
14787
14788bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
14789 SideEffectsKind AllowSideEffects,
14790 bool InConstantContext) const {
14791 assert(!isValueDependent() &&((void)0)
14792 "Expression evaluator can't be called on a dependent expression.")((void)0);
14793
14794 if (!getType()->isRealFloatingType())
14795 return false;
14796
14797 EvalResult ExprResult;
14798 if (!EvaluateAsRValue(ExprResult, Ctx, InConstantContext) ||
14799 !ExprResult.Val.isFloat() ||
14800 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14801 return false;
14802
14803 Result = ExprResult.Val.getFloat();
14804 return true;
14805}
14806
14807bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
14808 bool InConstantContext) const {
14809 assert(!isValueDependent() &&((void)0)
14810 "Expression evaluator can't be called on a dependent expression.")((void)0);
14811
14812 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
14813 Info.InConstantContext = InConstantContext;
14814 LValue LV;
14815 CheckedTemporaries CheckedTemps;
14816 if (!EvaluateLValue(this, LV, Info) || !Info.discardCleanups() ||
14817 Result.HasSideEffects ||
14818 !CheckLValueConstantExpression(Info, getExprLoc(),
14819 Ctx.getLValueReferenceType(getType()), LV,
14820 ConstantExprKind::Normal, CheckedTemps))
14821 return false;
14822
14823 LV.moveInto(Result.Val);
14824 return true;
14825}
14826
14827static bool EvaluateDestruction(const ASTContext &Ctx, APValue::LValueBase Base,
14828 APValue DestroyedValue, QualType Type,
14829 SourceLocation Loc, Expr::EvalStatus &EStatus,
14830 bool IsConstantDestruction) {
14831 EvalInfo Info(Ctx, EStatus,
14832 IsConstantDestruction ? EvalInfo::EM_ConstantExpression
14833 : EvalInfo::EM_ConstantFold);
14834 Info.setEvaluatingDecl(Base, DestroyedValue,
14835 EvalInfo::EvaluatingDeclKind::Dtor);
14836 Info.InConstantContext = IsConstantDestruction;
14837
14838 LValue LVal;
14839 LVal.set(Base);
14840
14841 if (!HandleDestruction(Info, Loc, Base, DestroyedValue, Type) ||
14842 EStatus.HasSideEffects)
14843 return false;
14844
14845 if (!Info.discardCleanups())
14846 llvm_unreachable("Unhandled cleanup; missing full expression marker?")__builtin_unreachable();
14847
14848 return true;
14849}
14850
14851bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
14852 ConstantExprKind Kind) const {
14853 assert(!isValueDependent() &&((void)0)
14854 "Expression evaluator can't be called on a dependent expression.")((void)0);
14855
14856 EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
14857 EvalInfo Info(Ctx, Result, EM);
14858 Info.InConstantContext = true;
14859
14860 // The type of the object we're initializing is 'const T' for a class NTTP.
14861 QualType T = getType();
14862 if (Kind == ConstantExprKind::ClassTemplateArgument)
14863 T.addConst();
14864
14865 // If we're evaluating a prvalue, fake up a MaterializeTemporaryExpr to
14866 // represent the result of the evaluation. CheckConstantExpression ensures
14867 // this doesn't escape.
14868 MaterializeTemporaryExpr BaseMTE(T, const_cast<Expr*>(this), true);
14869 APValue::LValueBase Base(&BaseMTE);
14870
14871 Info.setEvaluatingDecl(Base, Result.Val);
14872 LValue LVal;
14873 LVal.set(Base);
14874
14875 if (!::EvaluateInPlace(Result.Val, Info, LVal, this) || Result.HasSideEffects)
14876 return false;
14877
14878 if (!Info.discardCleanups())
14879 llvm_unreachable("Unhandled cleanup; missing full expression marker?")__builtin_unreachable();
14880
14881 if (!CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this),
14882 Result.Val, Kind))
14883 return false;
14884 if (!CheckMemoryLeaks(Info))
14885 return false;
14886
14887 // If this is a class template argument, it's required to have constant
14888 // destruction too.
14889 if (Kind == ConstantExprKind::ClassTemplateArgument &&
14890 (!EvaluateDestruction(Ctx, Base, Result.Val, T, getBeginLoc(), Result,
14891 true) ||
14892 Result.HasSideEffects)) {
14893 // FIXME: Prefix a note to indicate that the problem is lack of constant
14894 // destruction.
14895 return false;
14896 }
14897
14898 return true;
14899}
14900
14901bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
14902 const VarDecl *VD,
14903 SmallVectorImpl<PartialDiagnosticAt> &Notes,
14904 bool IsConstantInitialization) const {
14905 assert(!isValueDependent() &&((void)0)
14906 "Expression evaluator can't be called on a dependent expression.")((void)0);
14907
14908 // FIXME: Evaluating initializers for large array and record types can cause
14909 // performance problems. Only do so in C++11 for now.
14910 if (isPRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
14911 !Ctx.getLangOpts().CPlusPlus11)
14912 return false;
14913
14914 Expr::EvalStatus EStatus;
14915 EStatus.Diag = &Notes;
14916
14917 EvalInfo Info(Ctx, EStatus,
14918 (IsConstantInitialization && Ctx.getLangOpts().CPlusPlus11)
14919 ? EvalInfo::EM_ConstantExpression
14920 : EvalInfo::EM_ConstantFold);
14921 Info.setEvaluatingDecl(VD, Value);
14922 Info.InConstantContext = IsConstantInitialization;
14923
14924 SourceLocation DeclLoc = VD->getLocation();
14925 QualType DeclTy = VD->getType();
14926
14927 if (Info.EnableNewConstInterp) {
14928 auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
14929 if (!InterpCtx.evaluateAsInitializer(Info, VD, Value))
14930 return false;
14931 } else {
14932 LValue LVal;
14933 LVal.set(VD);
14934
14935 if (!EvaluateInPlace(Value, Info, LVal, this,
14936 /*AllowNonLiteralTypes=*/true) ||
14937 EStatus.HasSideEffects)
14938 return false;
14939
14940 // At this point, any lifetime-extended temporaries are completely
14941 // initialized.
14942 Info.performLifetimeExtension();
14943
14944 if (!Info.discardCleanups())
14945 llvm_unreachable("Unhandled cleanup; missing full expression marker?")__builtin_unreachable();
14946 }
14947 return CheckConstantExpression(Info, DeclLoc, DeclTy, Value,
14948 ConstantExprKind::Normal) &&
14949 CheckMemoryLeaks(Info);
14950}
14951
14952bool VarDecl::evaluateDestruction(
14953 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
14954 Expr::EvalStatus EStatus;
14955 EStatus.Diag = &Notes;
14956
14957 // Only treat the destruction as constant destruction if we formally have
14958 // constant initialization (or are usable in a constant expression).
14959 bool IsConstantDestruction = hasConstantInitialization();
14960
14961 // Make a copy of the value for the destructor to mutate, if we know it.
14962 // Otherwise, treat the value as default-initialized; if the destructor works
14963 // anyway, then the destruction is constant (and must be essentially empty).
14964 APValue DestroyedValue;
14965 if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent())
14966 DestroyedValue = *getEvaluatedValue();
14967 else if (!getDefaultInitValue(getType(), DestroyedValue))
14968 return false;
14969
14970 if (!EvaluateDestruction(getASTContext(), this, std::move(DestroyedValue),
14971 getType(), getLocation(), EStatus,
14972 IsConstantDestruction) ||
14973 EStatus.HasSideEffects)
14974 return false;
14975
14976 ensureEvaluatedStmt()->HasConstantDestruction = true;
14977 return true;
14978}
14979
14980/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
14981/// constant folded, but discard the result.
14982bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
14983 assert(!isValueDependent() &&((void)0)
14984 "Expression evaluator can't be called on a dependent expression.")((void)0);
14985
14986 EvalResult Result;
14987 return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) &&
14988 !hasUnacceptableSideEffect(Result, SEK);
14989}
14990
14991APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
14992 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
14993 assert(!isValueDependent() &&((void)0)
14994 "Expression evaluator can't be called on a dependent expression.")((void)0);
14995
14996 EvalResult EVResult;
14997 EVResult.Diag = Diag;
14998 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
14999 Info.InConstantContext = true;
15000
15001 bool Result = ::EvaluateAsRValue(this, EVResult, Ctx, Info);
15002 (void)Result;
15003 assert(Result && "Could not evaluate expression")((void)0);
15004 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer")((void)0);
15005
15006 return EVResult.Val.getInt();
15007}
15008
15009APSInt Expr::EvaluateKnownConstIntCheckOverflow(
15010 const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
15011 assert(!isValueDependent() &&((void)0)
15012 "Expression evaluator can't be called on a dependent expression.")((void)0);
15013
15014 EvalResult EVResult;
15015 EVResult.Diag = Diag;
15016 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
15017 Info.InConstantContext = true;
15018 Info.CheckingForUndefinedBehavior = true;
15019
15020 bool Result = ::EvaluateAsRValue(Info, this, EVResult.Val);
15021 (void)Result;
15022 assert(Result && "Could not evaluate expression")((void)0);
15023 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer")((void)0);
15024
15025 return EVResult.Val.getInt();
15026}
15027
15028void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
15029 assert(!isValueDependent() &&((void)0)
15030 "Expression evaluator can't be called on a dependent expression.")((void)0);
15031
15032 bool IsConst;
15033 EvalResult EVResult;
15034 if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) {
15035 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
15036 Info.CheckingForUndefinedBehavior = true;
15037 (void)::EvaluateAsRValue(Info, this, EVResult.Val);
15038 }
15039}
15040
15041bool Expr::EvalResult::isGlobalLValue() const {
15042 assert(Val.isLValue())((void)0);
15043 return IsGlobalLValue(Val.getLValueBase());
15044}
15045
15046/// isIntegerConstantExpr - this recursive routine will test if an expression is
15047/// an integer constant expression.
15048
15049/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
15050/// comma, etc
15051
15052// CheckICE - This function does the fundamental ICE checking: the returned
15053// ICEDiag contains an ICEKind indicating whether the expression is an ICE,
15054// and a (possibly null) SourceLocation indicating the location of the problem.
15055//
15056// Note that to reduce code duplication, this helper does no evaluation
15057// itself; the caller checks whether the expression is evaluatable, and
15058// in the rare cases where CheckICE actually cares about the evaluated
15059// value, it calls into Evaluate.
15060
15061namespace {
15062
15063enum ICEKind {
15064 /// This expression is an ICE.
15065 IK_ICE,
15066 /// This expression is not an ICE, but if it isn't evaluated, it's
15067 /// a legal subexpression for an ICE. This return value is used to handle
15068 /// the comma operator in C99 mode, and non-constant subexpressions.
15069 IK_ICEIfUnevaluated,
15070 /// This expression is not an ICE, and is not a legal subexpression for one.
15071 IK_NotICE
15072};
15073
15074struct ICEDiag {
15075 ICEKind Kind;
15076 SourceLocation Loc;
15077
15078 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
15079};
15080
15081}
15082
15083static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
15084
15085static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
15086
15087static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
15088 Expr::EvalResult EVResult;
15089 Expr::EvalStatus Status;
15090 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
15091
15092 Info.InConstantContext = true;
15093 if (!::EvaluateAsRValue(E, EVResult, Ctx, Info) || EVResult.HasSideEffects ||
15094 !EVResult.Val.isInt())
15095 return ICEDiag(IK_NotICE, E->getBeginLoc());
15096
15097 return NoDiag();
15098}
15099
15100static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
15101 assert(!E->isValueDependent() && "Should not see value dependent exprs!")((void)0);
15102 if (!E->getType()->isIntegralOrEnumerationType())
15103 return ICEDiag(IK_NotICE, E->getBeginLoc());
15104
15105 switch (E->getStmtClass()) {
15106#define ABSTRACT_STMT(Node)
15107#define STMT(Node, Base) case Expr::Node##Class:
15108#define EXPR(Node, Base)
15109#include "clang/AST/StmtNodes.inc"
15110 case Expr::PredefinedExprClass:
15111 case Expr::FloatingLiteralClass:
15112 case Expr::ImaginaryLiteralClass:
15113 case Expr::StringLiteralClass:
15114 case Expr::ArraySubscriptExprClass:
15115 case Expr::MatrixSubscriptExprClass:
15116 case Expr::OMPArraySectionExprClass:
15117 case Expr::OMPArrayShapingExprClass:
15118 case Expr::OMPIteratorExprClass:
15119 case Expr::MemberExprClass:
15120 case Expr::CompoundAssignOperatorClass:
15121 case Expr::CompoundLiteralExprClass:
15122 case Expr::ExtVectorElementExprClass:
15123 case Expr::DesignatedInitExprClass:
15124 case Expr::ArrayInitLoopExprClass:
15125 case Expr::ArrayInitIndexExprClass:
15126 case Expr::NoInitExprClass:
15127 case Expr::DesignatedInitUpdateExprClass:
15128 case Expr::ImplicitValueInitExprClass:
15129 case Expr::ParenListExprClass:
15130 case Expr::VAArgExprClass:
15131 case Expr::AddrLabelExprClass:
15132 case Expr::StmtExprClass:
15133 case Expr::CXXMemberCallExprClass:
15134 case Expr::CUDAKernelCallExprClass:
15135 case Expr::CXXAddrspaceCastExprClass:
15136 case Expr::CXXDynamicCastExprClass:
15137 case Expr::CXXTypeidExprClass:
15138 case Expr::CXXUuidofExprClass:
15139 case Expr::MSPropertyRefExprClass:
15140 case Expr::MSPropertySubscriptExprClass:
15141 case Expr::CXXNullPtrLiteralExprClass:
15142 case Expr::UserDefinedLiteralClass:
15143 case Expr::CXXThisExprClass:
15144 case Expr::CXXThrowExprClass:
15145 case Expr::CXXNewExprClass:
15146 case Expr::CXXDeleteExprClass:
15147 case Expr::CXXPseudoDestructorExprClass:
15148 case Expr::UnresolvedLookupExprClass:
15149 case Expr::TypoExprClass:
15150 case Expr::RecoveryExprClass:
15151 case Expr::DependentScopeDeclRefExprClass:
15152 case Expr::CXXConstructExprClass:
15153 case Expr::CXXInheritedCtorInitExprClass:
15154 case Expr::CXXStdInitializerListExprClass:
15155 case Expr::CXXBindTemporaryExprClass:
15156 case Expr::ExprWithCleanupsClass:
15157 case Expr::CXXTemporaryObjectExprClass:
15158 case Expr::CXXUnresolvedConstructExprClass:
15159 case Expr::CXXDependentScopeMemberExprClass:
15160 case Expr::UnresolvedMemberExprClass:
15161 case Expr::ObjCStringLiteralClass:
15162 case Expr::ObjCBoxedExprClass:
15163 case Expr::ObjCArrayLiteralClass:
15164 case Expr::ObjCDictionaryLiteralClass:
15165 case Expr::ObjCEncodeExprClass:
15166 case Expr::ObjCMessageExprClass:
15167 case Expr::ObjCSelectorExprClass:
15168 case Expr::ObjCProtocolExprClass:
15169 case Expr::ObjCIvarRefExprClass:
15170 case Expr::ObjCPropertyRefExprClass:
15171 case Expr::ObjCSubscriptRefExprClass:
15172 case Expr::ObjCIsaExprClass:
15173 case Expr::ObjCAvailabilityCheckExprClass:
15174 case Expr::ShuffleVectorExprClass:
15175 case Expr::ConvertVectorExprClass:
15176 case Expr::BlockExprClass:
15177 case Expr::NoStmtClass:
15178 case Expr::OpaqueValueExprClass:
15179 case Expr::PackExpansionExprClass:
15180 case Expr::SubstNonTypeTemplateParmPackExprClass:
15181 case Expr::FunctionParmPackExprClass:
15182 case Expr::AsTypeExprClass:
15183 case Expr::ObjCIndirectCopyRestoreExprClass:
15184 case Expr::MaterializeTemporaryExprClass:
15185 case Expr::PseudoObjectExprClass:
15186 case Expr::AtomicExprClass:
15187 case Expr::LambdaExprClass:
15188 case Expr::CXXFoldExprClass:
15189 case Expr::CoawaitExprClass:
15190 case Expr::DependentCoawaitExprClass:
15191 case Expr::CoyieldExprClass:
15192 case Expr::SYCLUniqueStableNameExprClass:
15193 return ICEDiag(IK_NotICE, E->getBeginLoc());
15194
15195 case Expr::InitListExprClass: {
15196 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
15197 // form "T x = { a };" is equivalent to "T x = a;".
15198 // Unless we're initializing a reference, T is a scalar as it is known to be
15199 // of integral or enumeration type.
15200 if (E->isPRValue())
15201 if (cast<InitListExpr>(E)->getNumInits() == 1)
15202 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
15203 return ICEDiag(IK_NotICE, E->getBeginLoc());
15204 }
15205
15206 case Expr::SizeOfPackExprClass:
15207 case Expr::GNUNullExprClass:
15208 case Expr::SourceLocExprClass:
15209 return NoDiag();
15210
15211 case Expr::SubstNonTypeTemplateParmExprClass:
15212 return
15213 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
15214
15215 case Expr::ConstantExprClass:
15216 return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx);
15217
15218 case Expr::ParenExprClass:
15219 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
15220 case Expr::GenericSelectionExprClass:
15221 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
15222 case Expr::IntegerLiteralClass:
15223 case Expr::FixedPointLiteralClass:
15224 case Expr::CharacterLiteralClass:
15225 case Expr::ObjCBoolLiteralExprClass:
15226 case Expr::CXXBoolLiteralExprClass:
15227 case Expr::CXXScalarValueInitExprClass:
15228 case Expr::TypeTraitExprClass:
15229 case Expr::ConceptSpecializationExprClass:
15230 case Expr::RequiresExprClass:
15231 case Expr::ArrayTypeTraitExprClass:
15232 case Expr::ExpressionTraitExprClass:
15233 case Expr::CXXNoexceptExprClass:
15234 return NoDiag();
15235 case Expr::CallExprClass:
15236 case Expr::CXXOperatorCallExprClass: {
15237 // C99 6.6/3 allows function calls within unevaluated subexpressions of
15238 // constant expressions, but they can never be ICEs because an ICE cannot
15239 // contain an operand of (pointer to) function type.
15240 const CallExpr *CE = cast<CallExpr>(E);
15241 if (CE->getBuiltinCallee())
15242 return CheckEvalInICE(E, Ctx);
15243 return ICEDiag(IK_NotICE, E->getBeginLoc());
15244 }
15245 case Expr::CXXRewrittenBinaryOperatorClass:
15246 return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(),
15247 Ctx);
15248 case Expr::DeclRefExprClass: {
15249 const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl();
15250 if (isa<EnumConstantDecl>(D))
15251 return NoDiag();
15252
15253 // C++ and OpenCL (FIXME: spec reference?) allow reading const-qualified
15254 // integer variables in constant expressions:
15255 //
15256 // C++ 7.1.5.1p2
15257 // A variable of non-volatile const-qualified integral or enumeration
15258 // type initialized by an ICE can be used in ICEs.
15259 //
15260 // We sometimes use CheckICE to check the C++98 rules in C++11 mode. In
15261 // that mode, use of reference variables should not be allowed.
15262 const VarDecl *VD = dyn_cast<VarDecl>(D);
15263 if (VD && VD->isUsableInConstantExpressions(Ctx) &&
15264 !VD->getType()->isReferenceType())
15265 return NoDiag();
15266
15267 return ICEDiag(IK_NotICE, E->getBeginLoc());
15268 }
15269 case Expr::UnaryOperatorClass: {
15270 const UnaryOperator *Exp = cast<UnaryOperator>(E);
15271 switch (Exp->getOpcode()) {
15272 case UO_PostInc:
15273 case UO_PostDec:
15274 case UO_PreInc:
15275 case UO_PreDec:
15276 case UO_AddrOf:
15277 case UO_Deref:
15278 case UO_Coawait:
15279 // C99 6.6/3 allows increment and decrement within unevaluated
15280 // subexpressions of constant expressions, but they can never be ICEs
15281 // because an ICE cannot contain an lvalue operand.
15282 return ICEDiag(IK_NotICE, E->getBeginLoc());
15283 case UO_Extension:
15284 case UO_LNot:
15285 case UO_Plus:
15286 case UO_Minus:
15287 case UO_Not:
15288 case UO_Real:
15289 case UO_Imag:
15290 return CheckICE(Exp->getSubExpr(), Ctx);
15291 }
15292 llvm_unreachable("invalid unary operator class")__builtin_unreachable();
15293 }
15294 case Expr::OffsetOfExprClass: {
15295 // Note that per C99, offsetof must be an ICE. And AFAIK, using
15296 // EvaluateAsRValue matches the proposed gcc behavior for cases like
15297 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
15298 // compliance: we should warn earlier for offsetof expressions with
15299 // array subscripts that aren't ICEs, and if the array subscripts
15300 // are ICEs, the value of the offsetof must be an integer constant.
15301 return CheckEvalInICE(E, Ctx);
15302 }
15303 case Expr::UnaryExprOrTypeTraitExprClass: {
15304 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
15305 if ((Exp->getKind() == UETT_SizeOf) &&
15306 Exp->getTypeOfArgument()->isVariableArrayType())
15307 return ICEDiag(IK_NotICE, E->getBeginLoc());
15308 return NoDiag();
15309 }
15310 case Expr::BinaryOperatorClass: {
15311 const BinaryOperator *Exp = cast<BinaryOperator>(E);
15312 switch (Exp->getOpcode()) {
15313 case BO_PtrMemD:
15314 case BO_PtrMemI:
15315 case BO_Assign:
15316 case BO_MulAssign:
15317 case BO_DivAssign:
15318 case BO_RemAssign:
15319 case BO_AddAssign:
15320 case BO_SubAssign:
15321 case BO_ShlAssign:
15322 case BO_ShrAssign:
15323 case BO_AndAssign:
15324 case BO_XorAssign:
15325 case BO_OrAssign:
15326 // C99 6.6/3 allows assignments within unevaluated subexpressions of
15327 // constant expressions, but they can never be ICEs because an ICE cannot
15328 // contain an lvalue operand.
15329 return ICEDiag(IK_NotICE, E->getBeginLoc());
15330
15331 case BO_Mul:
15332 case BO_Div:
15333 case BO_Rem:
15334 case BO_Add:
15335 case BO_Sub:
15336 case BO_Shl:
15337 case BO_Shr:
15338 case BO_LT:
15339 case BO_GT:
15340 case BO_LE:
15341 case BO_GE:
15342 case BO_EQ:
15343 case BO_NE:
15344 case BO_And:
15345 case BO_Xor:
15346 case BO_Or:
15347 case BO_Comma:
15348 case BO_Cmp: {
15349 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
15350 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
15351 if (Exp->getOpcode() == BO_Div ||
15352 Exp->getOpcode() == BO_Rem) {
15353 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
15354 // we don't evaluate one.
15355 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
15356 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
15357 if (REval == 0)
15358 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
15359 if (REval.isSigned() && REval.isAllOnesValue()) {
15360 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
15361 if (LEval.isMinSignedValue())
15362 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
15363 }
15364 }
15365 }
15366 if (Exp->getOpcode() == BO_Comma) {
15367 if (Ctx.getLangOpts().C99) {
15368 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
15369 // if it isn't evaluated.
15370 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
15371 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
15372 } else {
15373 // In both C89 and C++, commas in ICEs are illegal.
15374 return ICEDiag(IK_NotICE, E->getBeginLoc());
15375 }
15376 }
15377 return Worst(LHSResult, RHSResult);
15378 }
15379 case BO_LAnd:
15380 case BO_LOr: {
15381 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
15382 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
15383 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
15384 // Rare case where the RHS has a comma "side-effect"; we need
15385 // to actually check the condition to see whether the side
15386 // with the comma is evaluated.
15387 if ((Exp->getOpcode() == BO_LAnd) !=
15388 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
15389 return RHSResult;
15390 return NoDiag();
15391 }
15392
15393 return Worst(LHSResult, RHSResult);
15394 }
15395 }
15396 llvm_unreachable("invalid binary operator kind")__builtin_unreachable();
15397 }
15398 case Expr::ImplicitCastExprClass:
15399 case Expr::CStyleCastExprClass:
15400 case Expr::CXXFunctionalCastExprClass:
15401 case Expr::CXXStaticCastExprClass:
15402 case Expr::CXXReinterpretCastExprClass:
15403 case Expr::CXXConstCastExprClass:
15404 case Expr::ObjCBridgedCastExprClass: {
15405 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
15406 if (isa<ExplicitCastExpr>(E)) {
15407 if (const FloatingLiteral *FL
15408 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
15409 unsigned DestWidth = Ctx.getIntWidth(E->getType());
15410 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
15411 APSInt IgnoredVal(DestWidth, !DestSigned);
15412 bool Ignored;
15413 // If the value does not fit in the destination type, the behavior is
15414 // undefined, so we are not required to treat it as a constant
15415 // expression.
15416 if (FL->getValue().convertToInteger(IgnoredVal,
15417 llvm::APFloat::rmTowardZero,
15418 &Ignored) & APFloat::opInvalidOp)
15419 return ICEDiag(IK_NotICE, E->getBeginLoc());
15420 return NoDiag();
15421 }
15422 }
15423 switch (cast<CastExpr>(E)->getCastKind()) {
15424 case CK_LValueToRValue:
15425 case CK_AtomicToNonAtomic:
15426 case CK_NonAtomicToAtomic:
15427 case CK_NoOp:
15428 case CK_IntegralToBoolean:
15429 case CK_IntegralCast:
15430 return CheckICE(SubExpr, Ctx);
15431 default:
15432 return ICEDiag(IK_NotICE, E->getBeginLoc());
15433 }
15434 }
15435 case Expr::BinaryConditionalOperatorClass: {
15436 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
15437 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
15438 if (CommonResult.Kind == IK_NotICE) return CommonResult;
15439 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
15440 if (FalseResult.Kind == IK_NotICE) return FalseResult;
15441 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
15442 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
15443 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
15444 return FalseResult;
15445 }
15446 case Expr::ConditionalOperatorClass: {
15447 const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
15448 // If the condition (ignoring parens) is a __builtin_constant_p call,
15449 // then only the true side is actually considered in an integer constant
15450 // expression, and it is fully evaluated. This is an important GNU
15451 // extension. See GCC PR38377 for discussion.
15452 if (const CallExpr *CallCE
15453 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
15454 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
15455 return CheckEvalInICE(E, Ctx);
15456 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
15457 if (CondResult.Kind == IK_NotICE)
15458 return CondResult;
15459
15460 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
15461 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
15462
15463 if (TrueResult.Kind == IK_NotICE)
15464 return TrueResult;
15465 if (FalseResult.Kind == IK_NotICE)
15466 return FalseResult;
15467 if (CondResult.Kind == IK_ICEIfUnevaluated)
15468 return CondResult;
15469 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
15470 return NoDiag();
15471 // Rare case where the diagnostics depend on which side is evaluated
15472 // Note that if we get here, CondResult is 0, and at least one of
15473 // TrueResult and FalseResult is non-zero.
15474 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
15475 return FalseResult;
15476 return TrueResult;
15477 }
15478 case Expr::CXXDefaultArgExprClass:
15479 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
15480 case Expr::CXXDefaultInitExprClass:
15481 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
15482 case Expr::ChooseExprClass: {
15483 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
15484 }
15485 case Expr::BuiltinBitCastExprClass: {
15486 if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E)))
15487 return ICEDiag(IK_NotICE, E->getBeginLoc());
15488 return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx);
15489 }
15490 }
15491
15492 llvm_unreachable("Invalid StmtClass!")__builtin_unreachable();
15493}
15494
15495/// Evaluate an expression as a C++11 integral constant expression.
15496static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
15497 const Expr *E,
15498 llvm::APSInt *Value,
15499 SourceLocation *Loc) {
15500 if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
15501 if (Loc) *Loc = E->getExprLoc();
15502 return false;
15503 }
15504
15505 APValue Result;
15506 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
15507 return false;
15508
15509 if (!Result.isInt()) {
15510 if (Loc) *Loc = E->getExprLoc();
15511 return false;
15512 }
15513
15514 if (Value) *Value = Result.getInt();
15515 return true;
15516}
15517
15518bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
15519 SourceLocation *Loc) const {
15520 assert(!isValueDependent() &&((void)0)
15521 "Expression evaluator can't be called on a dependent expression.")((void)0);
15522
15523 if (Ctx.getLangOpts().CPlusPlus11)
15524 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
15525
15526 ICEDiag D = CheckICE(this, Ctx);
15527 if (D.Kind != IK_ICE) {
15528 if (Loc) *Loc = D.Loc;
15529 return false;
15530 }
15531 return true;
15532}
15533
15534Optional<llvm::APSInt> Expr::getIntegerConstantExpr(const ASTContext &Ctx,
15535 SourceLocation *Loc,
15536 bool isEvaluated) const {
15537 assert(!isValueDependent() &&((void)0)
15538 "Expression evaluator can't be called on a dependent expression.")((void)0);
15539
15540 APSInt Value;
15541
15542 if (Ctx.getLangOpts().CPlusPlus11) {
15543 if (EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc))
15544 return Value;
15545 return None;
15546 }
15547
15548 if (!isIntegerConstantExpr(Ctx, Loc))
15549 return None;
15550
15551 // The only possible side-effects here are due to UB discovered in the
15552 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
15553 // required to treat the expression as an ICE, so we produce the folded
15554 // value.
15555 EvalResult ExprResult;
15556 Expr::EvalStatus Status;
15557 EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects);
15558 Info.InConstantContext = true;
15559
15560 if (!::EvaluateAsInt(this, ExprResult, Ctx, SE_AllowSideEffects, Info))
15561 llvm_unreachable("ICE cannot be evaluated!")__builtin_unreachable();
15562
15563 return ExprResult.Val.getInt();
15564}
15565
15566bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
15567 assert(!isValueDependent() &&((void)0)
15568 "Expression evaluator can't be called on a dependent expression.")((void)0);
15569
15570 return CheckICE(this, Ctx).Kind == IK_ICE;
15571}
15572
15573bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
15574 SourceLocation *Loc) const {
15575 assert(!isValueDependent() &&((void)0)
15576 "Expression evaluator can't be called on a dependent expression.")((void)0);
15577
15578 // We support this checking in C++98 mode in order to diagnose compatibility
15579 // issues.
15580 assert(Ctx.getLangOpts().CPlusPlus)((void)0);
15581
15582 // Build evaluation settings.
15583 Expr::EvalStatus Status;
15584 SmallVector<PartialDiagnosticAt, 8> Diags;
15585 Status.Diag = &Diags;
15586 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
15587
15588 APValue Scratch;
15589 bool IsConstExpr =
15590 ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch) &&
15591 // FIXME: We don't produce a diagnostic for this, but the callers that
15592 // call us on arbitrary full-expressions should generally not care.
15593 Info.discardCleanups() && !Status.HasSideEffects;
15594
15595 if (!Diags.empty()) {
15596 IsConstExpr = false;
15597 if (Loc) *Loc = Diags[0].first;
15598 } else if (!IsConstExpr) {
15599 // FIXME: This shouldn't happen.
15600 if (Loc) *Loc = getExprLoc();
15601 }
15602
15603 return IsConstExpr;
15604}
15605
15606bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
15607 const FunctionDecl *Callee,
15608 ArrayRef<const Expr*> Args,
15609 const Expr *This) const {
15610 assert(!isValueDependent() &&((void)0)
15611 "Expression evaluator can't be called on a dependent expression.")((void)0);
15612
15613 Expr::EvalStatus Status;
15614 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
15615 Info.InConstantContext = true;
15616
15617 LValue ThisVal;
15618 const LValue *ThisPtr = nullptr;
15619 if (This) {
15620#ifndef NDEBUG1
15621 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
15622 assert(MD && "Don't provide `this` for non-methods.")((void)0);
15623 assert(!MD->isStatic() && "Don't provide `this` for static methods.")((void)0);
15624#endif
15625 if (!This->isValueDependent() &&
15626 EvaluateObjectArgument(Info, This, ThisVal) &&
15627 !Info.EvalStatus.HasSideEffects)
15628 ThisPtr = &ThisVal;
15629
15630 // Ignore any side-effects from a failed evaluation. This is safe because
15631 // they can't interfere with any other argument evaluation.
15632 Info.EvalStatus.HasSideEffects = false;
15633 }
15634
15635 CallRef Call = Info.CurrentCall->createCall(Callee);
15636 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
15637 I != E; ++I) {
15638 unsigned Idx = I - Args.begin();
15639 if (Idx >= Callee->getNumParams())
15640 break;
15641 const ParmVarDecl *PVD = Callee->getParamDecl(Idx);
15642 if ((*I)->isValueDependent() ||
15643 !EvaluateCallArg(PVD, *I, Call, Info) ||
15644 Info.EvalStatus.HasSideEffects) {
15645 // If evaluation fails, throw away the argument entirely.
15646 if (APValue *Slot = Info.getParamSlot(Call, PVD))
15647 *Slot = APValue();
15648 }
15649
15650 // Ignore any side-effects from a failed evaluation. This is safe because
15651 // they can't interfere with any other argument evaluation.
15652 Info.EvalStatus.HasSideEffects = false;
15653 }
15654
15655 // Parameter cleanups happen in the caller and are not part of this
15656 // evaluation.
15657 Info.discardCleanups();
15658 Info.EvalStatus.HasSideEffects = false;
15659
15660 // Build fake call to Callee.
15661 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, Call);
15662 // FIXME: Missing ExprWithCleanups in enable_if conditions?
15663 FullExpressionRAII Scope(Info);
15664 return Evaluate(Value, Info, this) && Scope.destroy() &&
15665 !Info.EvalStatus.HasSideEffects;
15666}
15667
15668bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
15669 SmallVectorImpl<
15670 PartialDiagnosticAt> &Diags) {
15671 // FIXME: It would be useful to check constexpr function templates, but at the
15672 // moment the constant expression evaluator cannot cope with the non-rigorous
15673 // ASTs which we build for dependent expressions.
15674 if (FD->isDependentContext())
15675 return true;
15676
15677 Expr::EvalStatus Status;
15678 Status.Diag = &Diags;
15679
15680 EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
15681 Info.InConstantContext = true;
15682 Info.CheckingPotentialConstantExpression = true;
15683
15684 // The constexpr VM attempts to compile all methods to bytecode here.
15685 if (Info.EnableNewConstInterp) {
15686 Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD);
15687 return Diags.empty();
15688 }
15689
15690 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
15691 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
15692
15693 // Fabricate an arbitrary expression on the stack and pretend that it
15694 // is a temporary being used as the 'this' pointer.
15695 LValue This;
15696 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
15697 This.set({&VIE, Info.CurrentCall->Index});
15698
15699 ArrayRef<const Expr*> Args;
15700
15701 APValue Scratch;
15702 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
15703 // Evaluate the call as a constant initializer, to allow the construction
15704 // of objects of non-literal types.
15705 Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
15706 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
15707 } else {
15708 SourceLocation Loc = FD->getLocation();
15709 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr,
15710 Args, CallRef(), FD->getBody(), Info, Scratch, nullptr);
15711 }
15712
15713 return Diags.empty();
15714}
15715
15716bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
15717 const FunctionDecl *FD,
15718 SmallVectorImpl<
15719 PartialDiagnosticAt> &Diags) {
15720 assert(!E->isValueDependent() &&((void)0)
15721 "Expression evaluator can't be called on a dependent expression.")((void)0);
15722
15723 Expr::EvalStatus Status;
15724 Status.Diag = &Diags;
15725
15726 EvalInfo Info(FD->getASTContext(), Status,
15727 EvalInfo::EM_ConstantExpressionUnevaluated);
15728 Info.InConstantContext = true;
15729 Info.CheckingPotentialConstantExpression = true;
15730
15731 // Fabricate a call stack frame to give the arguments a plausible cover story.
15732 CallStackFrame Frame(Info, SourceLocation(), FD, /*This*/ nullptr, CallRef());
15733
15734 APValue ResultScratch;
15735 Evaluate(ResultScratch, Info, E);
15736 return Diags.empty();
15737}
15738
15739bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
15740 unsigned Type) const {
15741 if (!getType()->isPointerType())
15742 return false;
15743
15744 Expr::EvalStatus Status;
15745 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
15746 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);
15747}

/usr/src/gnu/usr.bin/clang/libclangAST/../../../llvm/llvm/include/llvm/ADT/APSInt.h

1//===-- llvm/ADT/APSInt.h - Arbitrary Precision Signed Int -----*- C++ -*--===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the APSInt class, which is a simple class that
10// represents an arbitrary sized integer that knows its signedness.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_ADT_APSINT_H
15#define LLVM_ADT_APSINT_H
16
17#include "llvm/ADT/APInt.h"
18
19namespace llvm {
20
21/// An arbitrary precision integer that knows its signedness.
22class LLVM_NODISCARD[[clang::warn_unused_result]] APSInt : public APInt {
23
Assigned value is garbage or undefined
23 bool IsUnsigned;
24
25public:
26 /// Default constructor that creates an uninitialized APInt.
27 explicit APSInt() : IsUnsigned(false) {}
28
29 /// Create an APSInt with the specified width, default to unsigned.
30 explicit APSInt(uint32_t BitWidth, bool isUnsigned = true)
31 : APInt(BitWidth, 0), IsUnsigned(isUnsigned) {}
32
33 explicit APSInt(APInt I, bool isUnsigned = true)
34 : APInt(std::move(I)), IsUnsigned(isUnsigned) {}
35
36 /// Construct an APSInt from a string representation.
37 ///
38 /// This constructor interprets the string \p Str using the radix of 10.
39 /// The interpretation stops at the end of the string. The bit width of the
40 /// constructed APSInt is determined automatically.
41 ///
42 /// \param Str the string to be interpreted.
43 explicit APSInt(StringRef Str);
44
45 /// Determine sign of this APSInt.
46 ///
47 /// \returns true if this APSInt is negative, false otherwise
48 bool isNegative() const { return isSigned() && APInt::isNegative(); }
49
50 /// Determine if this APSInt Value is non-negative (>= 0)
51 ///
52 /// \returns true if this APSInt is non-negative, false otherwise
53 bool isNonNegative() const { return !isNegative(); }
54
55 /// Determine if this APSInt Value is positive.
56 ///
57 /// This tests if the value of this APSInt is positive (> 0). Note
58 /// that 0 is not a positive value.
59 ///
60 /// \returns true if this APSInt is positive.
61 bool isStrictlyPositive() const { return isNonNegative() && !isNullValue(); }
62
63 APSInt &operator=(APInt RHS) {
64 // Retain our current sign.
65 APInt::operator=(std::move(RHS));
66 return *this;
67 }
68
69 APSInt &operator=(uint64_t RHS) {
70 // Retain our current sign.
71 APInt::operator=(RHS);
72 return *this;
73 }
74
75 // Query sign information.
76 bool isSigned() const { return !IsUnsigned; }
77 bool isUnsigned() const { return IsUnsigned; }
78 void setIsUnsigned(bool Val) { IsUnsigned = Val; }
79 void setIsSigned(bool Val) { IsUnsigned = !Val; }
80
81 /// Append this APSInt to the specified SmallString.
82 void toString(SmallVectorImpl<char> &Str, unsigned Radix = 10) const {
83 APInt::toString(Str, Radix, isSigned());
84 }
85 using APInt::toString;
86
87 /// Get the correctly-extended \c int64_t value.
88 int64_t getExtValue() const {
89 assert(getMinSignedBits() <= 64 && "Too many bits for int64_t")((void)0);
90 return isSigned() ? getSExtValue() : getZExtValue();
91 }
92
93 APSInt trunc(uint32_t width) const {
94 return APSInt(APInt::trunc(width), IsUnsigned);
95 }
96
97 APSInt extend(uint32_t width) const {
98 if (IsUnsigned)
99 return APSInt(zext(width), IsUnsigned);
100 else
101 return APSInt(sext(width), IsUnsigned);
102 }
103
104 APSInt extOrTrunc(uint32_t width) const {
105 if (IsUnsigned)
106 return APSInt(zextOrTrunc(width), IsUnsigned);
107 else
108 return APSInt(sextOrTrunc(width), IsUnsigned);
109 }
110
111 const APSInt &operator%=(const APSInt &RHS) {
112 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
113 if (IsUnsigned)
114 *this = urem(RHS);
115 else
116 *this = srem(RHS);
117 return *this;
118 }
119 const APSInt &operator/=(const APSInt &RHS) {
120 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
121 if (IsUnsigned)
122 *this = udiv(RHS);
123 else
124 *this = sdiv(RHS);
125 return *this;
126 }
127 APSInt operator%(const APSInt &RHS) const {
128 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
129 return IsUnsigned ? APSInt(urem(RHS), true) : APSInt(srem(RHS), false);
130 }
131 APSInt operator/(const APSInt &RHS) const {
132 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
133 return IsUnsigned ? APSInt(udiv(RHS), true) : APSInt(sdiv(RHS), false);
134 }
135
136 APSInt operator>>(unsigned Amt) const {
137 return IsUnsigned ? APSInt(lshr(Amt), true) : APSInt(ashr(Amt), false);
138 }
139 APSInt& operator>>=(unsigned Amt) {
140 if (IsUnsigned)
141 lshrInPlace(Amt);
142 else
143 ashrInPlace(Amt);
144 return *this;
145 }
146
147 inline bool operator<(const APSInt& RHS) const {
148 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
149 return IsUnsigned ? ult(RHS) : slt(RHS);
150 }
151 inline bool operator>(const APSInt& RHS) const {
152 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
153 return IsUnsigned ? ugt(RHS) : sgt(RHS);
154 }
155 inline bool operator<=(const APSInt& RHS) const {
156 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
157 return IsUnsigned ? ule(RHS) : sle(RHS);
158 }
159 inline bool operator>=(const APSInt& RHS) const {
160 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
161 return IsUnsigned ? uge(RHS) : sge(RHS);
162 }
163 inline bool operator==(const APSInt& RHS) const {
164 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
165 return eq(RHS);
166 }
167 inline bool operator!=(const APSInt& RHS) const {
168 return !((*this) == RHS);
169 }
170
171 bool operator==(int64_t RHS) const {
172 return compareValues(*this, get(RHS)) == 0;
173 }
174 bool operator!=(int64_t RHS) const {
175 return compareValues(*this, get(RHS)) != 0;
176 }
177 bool operator<=(int64_t RHS) const {
178 return compareValues(*this, get(RHS)) <= 0;
179 }
180 bool operator>=(int64_t RHS) const {
181 return compareValues(*this, get(RHS)) >= 0;
182 }
183 bool operator<(int64_t RHS) const {
184 return compareValues(*this, get(RHS)) < 0;
185 }
186 bool operator>(int64_t RHS) const {
187 return compareValues(*this, get(RHS)) > 0;
188 }
189
190 // The remaining operators just wrap the logic of APInt, but retain the
191 // signedness information.
192
193 APSInt operator<<(unsigned Bits) const {
194 return APSInt(static_cast<const APInt&>(*this) << Bits, IsUnsigned);
195 }
196 APSInt& operator<<=(unsigned Amt) {
197 static_cast<APInt&>(*this) <<= Amt;
198 return *this;
199 }
200
201 APSInt& operator++() {
202 ++(static_cast<APInt&>(*this));
203 return *this;
204 }
205 APSInt& operator--() {
206 --(static_cast<APInt&>(*this));
207 return *this;
208 }
209 APSInt operator++(int) {
210 return APSInt(++static_cast<APInt&>(*this), IsUnsigned);
211 }
212 APSInt operator--(int) {
213 return APSInt(--static_cast<APInt&>(*this), IsUnsigned);
214 }
215 APSInt operator-() const {
216 return APSInt(-static_cast<const APInt&>(*this), IsUnsigned);
217 }
218 APSInt& operator+=(const APSInt& RHS) {
219 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
220 static_cast<APInt&>(*this) += RHS;
221 return *this;
222 }
223 APSInt& operator-=(const APSInt& RHS) {
224 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
225 static_cast<APInt&>(*this) -= RHS;
226 return *this;
227 }
228 APSInt& operator*=(const APSInt& RHS) {
229 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
230 static_cast<APInt&>(*this) *= RHS;
231 return *this;
232 }
233 APSInt& operator&=(const APSInt& RHS) {
234 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
235 static_cast<APInt&>(*this) &= RHS;
236 return *this;
237 }
238 APSInt& operator|=(const APSInt& RHS) {
239 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
240 static_cast<APInt&>(*this) |= RHS;
241 return *this;
242 }
243 APSInt& operator^=(const APSInt& RHS) {
244 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
245 static_cast<APInt&>(*this) ^= RHS;
246 return *this;
247 }
248
249 APSInt operator&(const APSInt& RHS) const {
250 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
251 return APSInt(static_cast<const APInt&>(*this) & RHS, IsUnsigned);
252 }
253
254 APSInt operator|(const APSInt& RHS) const {
255 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
256 return APSInt(static_cast<const APInt&>(*this) | RHS, IsUnsigned);
257 }
258
259 APSInt operator^(const APSInt &RHS) const {
260 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
261 return APSInt(static_cast<const APInt&>(*this) ^ RHS, IsUnsigned);
262 }
263
264 APSInt operator*(const APSInt& RHS) const {
265 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
266 return APSInt(static_cast<const APInt&>(*this) * RHS, IsUnsigned);
267 }
268 APSInt operator+(const APSInt& RHS) const {
269 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
270 return APSInt(static_cast<const APInt&>(*this) + RHS, IsUnsigned);
271 }
272 APSInt operator-(const APSInt& RHS) const {
273 assert(IsUnsigned == RHS.IsUnsigned && "Signedness mismatch!")((void)0);
274 return APSInt(static_cast<const APInt&>(*this) - RHS, IsUnsigned);
275 }
276 APSInt operator~() const {
277 return APSInt(~static_cast<const APInt&>(*this), IsUnsigned);
278 }
279
280 /// Return the APSInt representing the maximum integer value with the given
281 /// bit width and signedness.
282 static APSInt getMaxValue(uint32_t numBits, bool Unsigned) {
283 return APSInt(Unsigned ? APInt::getMaxValue(numBits)
284 : APInt::getSignedMaxValue(numBits), Unsigned);
285 }
286
287 /// Return the APSInt representing the minimum integer value with the given
288 /// bit width and signedness.
289 static APSInt getMinValue(uint32_t numBits, bool Unsigned) {
290 return APSInt(Unsigned ? APInt::getMinValue(numBits)
291 : APInt::getSignedMinValue(numBits), Unsigned);
292 }
293
294 /// Determine if two APSInts have the same value, zero- or
295 /// sign-extending as needed.
296 static bool isSameValue(const APSInt &I1, const APSInt &I2) {
297 return !compareValues(I1, I2);
298 }
299
300 /// Compare underlying values of two numbers.
301 static int compareValues(const APSInt &I1, const APSInt &I2) {
302 if (I1.getBitWidth() == I2.getBitWidth() && I1.isSigned() == I2.isSigned())
303 return I1.IsUnsigned ? I1.compare(I2) : I1.compareSigned(I2);
304
305 // Check for a bit-width mismatch.
306 if (I1.getBitWidth() > I2.getBitWidth())
307 return compareValues(I1, I2.extend(I1.getBitWidth()));
308 if (I2.getBitWidth() > I1.getBitWidth())
309 return compareValues(I1.extend(I2.getBitWidth()), I2);
310
311 // We have a signedness mismatch. Check for negative values and do an
312 // unsigned compare if both are positive.
313 if (I1.isSigned()) {
314 assert(!I2.isSigned() && "Expected signed mismatch")((void)0);
315 if (I1.isNegative())
316 return -1;
317 } else {
318 assert(I2.isSigned() && "Expected signed mismatch")((void)0);
319 if (I2.isNegative())
320 return 1;
321 }
322
323 return I1.compare(I2);
324 }
325
326 static APSInt get(int64_t X) { return APSInt(APInt(64, X), false); }
327 static APSInt getUnsigned(uint64_t X) { return APSInt(APInt(64, X), true); }
328
329 /// Used to insert APSInt objects, or objects that contain APSInt objects,
330 /// into FoldingSets.
331 void Profile(FoldingSetNodeID& ID) const;
332};
333
334inline bool operator==(int64_t V1, const APSInt &V2) { return V2 == V1; }
335inline bool operator!=(int64_t V1, const APSInt &V2) { return V2 != V1; }
336inline bool operator<=(int64_t V1, const APSInt &V2) { return V2 >= V1; }
337inline bool operator>=(int64_t V1, const APSInt &V2) { return V2 <= V1; }
338inline bool operator<(int64_t V1, const APSInt &V2) { return V2 > V1; }
339inline bool operator>(int64_t V1, const APSInt &V2) { return V2 < V1; }
340
341inline raw_ostream &operator<<(raw_ostream &OS, const APSInt &I) {
342 I.print(OS, I.isSigned());
343 return OS;
344}
345
346/// Provide DenseMapInfo for APSInt, using the DenseMapInfo for APInt.
347template <> struct DenseMapInfo<APSInt> {
348 static inline APSInt getEmptyKey() {
349 return APSInt(DenseMapInfo<APInt>::getEmptyKey());
350 }
351
352 static inline APSInt getTombstoneKey() {
353 return APSInt(DenseMapInfo<APInt>::getTombstoneKey());
354 }
355
356 static unsigned getHashValue(const APSInt &Key) {
357 return DenseMapInfo<APInt>::getHashValue(Key);
358 }
359
360 static bool isEqual(const APSInt &LHS, const APSInt &RHS) {
361 return LHS.getBitWidth() == RHS.getBitWidth() &&
362 LHS.isUnsigned() == RHS.isUnsigned() && LHS == RHS;
363 }
364};
365
366} // end namespace llvm
367
368#endif