File: | src/gnu/usr.bin/clang/libclangAST/../../../llvm/clang/lib/AST/ExprConstant.cpp |
Warning: | line 3181, column 27 Called C++ object pointer is null |
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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 | ||||
65 | using namespace clang; | |||
66 | using llvm::APFixedPoint; | |||
67 | using llvm::APInt; | |||
68 | using llvm::APSInt; | |||
69 | using llvm::APFloat; | |||
70 | using llvm::FixedPointSemantics; | |||
71 | using llvm::Optional; | |||
72 | ||||
73 | namespace { | |||
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 | ||||
665 | static bool HandleDestruction(EvalInfo &Info, const Expr *E, | |||
666 | const LValue &This, QualType ThisType); | |||
667 | static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc, | |||
668 | APValue::LValueBase LVBase, APValue &Value, | |||
669 | QualType T); | |||
670 | ||||
671 | namespace { | |||
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 | ||||
728 | namespace llvm { | |||
729 | template<> 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 | ||||
746 | namespace { | |||
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 | ||||
1399 | bool 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 | ||||
1415 | void 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 | ||||
1422 | void 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 | ||||
1437 | CallStackFrame::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 | ||||
1446 | CallStackFrame::~CallStackFrame() { | |||
1447 | assert(Info.CurrentCall == this && "calls retired out of order")((void)0); | |||
1448 | --Info.CallStackDepth; | |||
1449 | Info.CurrentCall = Caller; | |||
1450 | } | |||
1451 | ||||
1452 | static bool isRead(AccessKinds AK) { | |||
1453 | return AK == AK_Read || AK == AK_ReadObjectRepresentation; | |||
1454 | } | |||
1455 | ||||
1456 | static 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 | ||||
1474 | static bool isAnyAccess(AccessKinds AK) { | |||
1475 | return isRead(AK) || isModification(AK); | |||
1476 | } | |||
1477 | ||||
1478 | /// Is this an access per the C++ definition? | |||
1479 | static 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? | |||
1484 | static 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 | ||||
1508 | namespace { | |||
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()) { | |||
1538 | makeComplexFloat(); | |||
1539 | FloatReal = v.getComplexFloatReal(); | |||
1540 | FloatImag = v.getComplexFloatImag(); | |||
1541 | } else { | |||
1542 | makeComplexInt(); | |||
1543 | IntReal = v.getComplexIntReal(); | |||
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 | ||||
1810 | static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E); | |||
1811 | static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, | |||
1812 | const LValue &This, const Expr *E, | |||
1813 | bool AllowNonLiteralTypes = false); | |||
1814 | static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info, | |||
1815 | bool InvalidBaseOK = false); | |||
1816 | static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info, | |||
1817 | bool InvalidBaseOK = false); | |||
1818 | static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, | |||
1819 | EvalInfo &Info); | |||
1820 | static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info); | |||
1821 | static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info); | |||
1822 | static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, | |||
1823 | EvalInfo &Info); | |||
1824 | static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info); | |||
1825 | static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info); | |||
1826 | static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result, | |||
1827 | EvalInfo &Info); | |||
1828 | static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result); | |||
1829 | ||||
1830 | /// Evaluate an integer or fixed point expression into an APResult. | |||
1831 | static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result, | |||
1832 | EvalInfo &Info); | |||
1833 | ||||
1834 | /// Evaluate only a fixed point expression into an APResult. | |||
1835 | static 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). | |||
1844 | static 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 | ||||
1852 | template<typename KeyT> | |||
1853 | APValue &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. | |||
1862 | APValue &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 | ||||
1873 | APValue &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 | ||||
1893 | APValue *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. | |||
1909 | void 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. | |||
1950 | static 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? | |||
1960 | static 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 | ||||
1966 | static 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 | ||||
2028 | static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) { | |||
2029 | return LVal.Base.dyn_cast<const ValueDecl*>(); | |||
2030 | } | |||
2031 | ||||
2032 | static 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 | ||||
2039 | static bool IsWeakLValue(const LValue &Value) { | |||
2040 | const ValueDecl *Decl = GetLValueBaseDecl(Value); | |||
2041 | return Decl && Decl->isWeak(); | |||
2042 | } | |||
2043 | ||||
2044 | static 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 | ||||
2055 | static 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 | ||||
2069 | static 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 | ||||
2101 | enum 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. | |||
2108 | using CheckedTemporaries = | |||
2109 | llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>; | |||
2110 | ||||
2111 | static 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. | |||
2121 | static 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. | |||
2281 | static 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. | |||
2301 | static 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 | ||||
2331 | static 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. | |||
2415 | static 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. | |||
2430 | static 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". | |||
2440 | static 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 | ||||
2452 | static 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 | ||||
2467 | static 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 | ||||
2505 | static 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 | ||||
2515 | template<typename T> | |||
2516 | static 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 | ||||
2523 | static 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". | |||
2544 | static 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. | |||
2555 | static 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 | ||||
2595 | static 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 | ||||
2608 | static 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 | ||||
2621 | static 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 | ||||
2636 | static 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 | ||||
2657 | static 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). | |||
2707 | template<typename Operation> | |||
2708 | static 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. | |||
2730 | static 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. | |||
2832 | static 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 | ||||
2872 | static 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 | } | |||
2884 | static 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 | ||||
2897 | static 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 | ||||
2909 | template <typename APTy> | |||
2910 | static bool | |||
2911 | handleCompareOpForVectorHelper(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 | ||||
2939 | static 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. | |||
2952 | static 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. | |||
3023 | static 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 | ||||
3052 | static 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 | ||||
3066 | static 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 | ||||
3091 | static 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. | |||
3105 | static 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. | |||
3121 | static 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. | |||
3136 | static 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. | |||
3146 | static 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. | |||
3177 | static 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 | ||||
3188 | static 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. | |||
3200 | static 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. | |||
3222 | static 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. | |||
3347 | static 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. | |||
3361 | static 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. | |||
3394 | static 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. | |||
3417 | static 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. | |||
3442 | static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD); | |||
3443 | static bool isReadByLvalueToRvalueConversion(QualType T) { | |||
3444 | CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); | |||
3445 | return !RD || isReadByLvalueToRvalueConversion(RD); | |||
3446 | } | |||
3447 | static 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. | |||
3469 | static 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 | ||||
3502 | static 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 | ||||
3542 | namespace { | |||
3543 | /// A handle to a complete object (an object that is not a subobject of | |||
3544 | /// another object). | |||
3545 | struct 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 | ||||
3577 | static 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. | |||
3592 | template<typename SubobjectHandler> | |||
3593 | typename SubobjectHandler::result_type | |||
3594 | findSubobject(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 | ||||
3791 | namespace { | |||
3792 | struct 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. | |||
3818 | static 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 | ||||
3827 | namespace { | |||
3828 | struct 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 | ||||
3873 | const AccessKinds ModifySubobjectHandler::AccessKind; | |||
3874 | ||||
3875 | /// Update the designated sub-object of an rvalue to the given value. | |||
3876 | static 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. | |||
3886 | static 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. | |||
3923 | static 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. | |||
3943 | static 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. | |||
4208 | static bool | |||
4209 | handleLValueToRValueConversion(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. | |||
4265 | static 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 | ||||
4279 | namespace { | |||
4280 | struct 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 | ||||
4401 | const AccessKinds CompoundAssignSubobjectHandler::AccessKind; | |||
4402 | ||||
4403 | /// Perform a compound assignment of LVal <op>= RVal. | |||
4404 | static 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 | ||||
4424 | namespace { | |||
4425 | struct 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. | |||
4552 | static 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. | |||
4569 | static 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. | |||
4595 | static 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 | ||||
4677 | static 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. | |||
4697 | static 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. | |||
4735 | static 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 | ||||
4778 | namespace { | |||
4779 | enum 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 | ||||
4795 | static 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 | ||||
4823 | static 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 | ||||
4837 | static 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). | |||
4847 | static 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 | ||||
4859 | namespace { | |||
4860 | /// A location where the result (returned value) of evaluating a | |||
4861 | /// statement should be stored. | |||
4862 | struct 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 | ||||
4869 | struct 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 | ||||
4883 | static 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. | |||
4888 | static 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. | |||
4912 | static 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. | |||
4985 | static 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. | |||
5414 | static 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. | |||
5439 | static 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 | ||||
5501 | namespace { | |||
5502 | struct 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. | |||
5514 | static 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. | |||
5555 | static bool | |||
5556 | checkNonVirtualMemberCallThisPointer(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 | ||||
5564 | struct 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 | ||||
5571 | static 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. | |||
5581 | static 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. | |||
5636 | static 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. | |||
5701 | static 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. | |||
5728 | static 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. | |||
5742 | static 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 | ||||
5836 | namespace { | |||
5837 | struct 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 | ||||
5884 | const 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. | |||
5890 | static 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 | ||||
5986 | static 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. | |||
6012 | static 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. | |||
6050 | static 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. | |||
6070 | static 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 |