Bug Summary

File:src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateDeduction.cpp
Warning:line 2171, column 31
Called C++ object pointer is null

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaTemplateDeduction.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include/clang/Sema -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../include -I /usr/src/gnu/usr.bin/clang/libclangSema/obj -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateDeduction.cpp
1//===- SemaTemplateDeduction.cpp - Template Argument Deduction ------------===//
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 C++ template argument deduction.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Sema/TemplateDeduction.h"
14#include "TreeTransform.h"
15#include "TypeLocBuilder.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/ASTLambda.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/DeclAccessPair.h"
20#include "clang/AST/DeclBase.h"
21#include "clang/AST/DeclCXX.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/DeclarationName.h"
24#include "clang/AST/Expr.h"
25#include "clang/AST/ExprCXX.h"
26#include "clang/AST/NestedNameSpecifier.h"
27#include "clang/AST/RecursiveASTVisitor.h"
28#include "clang/AST/TemplateBase.h"
29#include "clang/AST/TemplateName.h"
30#include "clang/AST/Type.h"
31#include "clang/AST/TypeLoc.h"
32#include "clang/AST/UnresolvedSet.h"
33#include "clang/Basic/AddressSpaces.h"
34#include "clang/Basic/ExceptionSpecificationType.h"
35#include "clang/Basic/LLVM.h"
36#include "clang/Basic/LangOptions.h"
37#include "clang/Basic/PartialDiagnostic.h"
38#include "clang/Basic/SourceLocation.h"
39#include "clang/Basic/Specifiers.h"
40#include "clang/Sema/Ownership.h"
41#include "clang/Sema/Sema.h"
42#include "clang/Sema/Template.h"
43#include "llvm/ADT/APInt.h"
44#include "llvm/ADT/APSInt.h"
45#include "llvm/ADT/ArrayRef.h"
46#include "llvm/ADT/DenseMap.h"
47#include "llvm/ADT/FoldingSet.h"
48#include "llvm/ADT/Optional.h"
49#include "llvm/ADT/SmallBitVector.h"
50#include "llvm/ADT/SmallPtrSet.h"
51#include "llvm/ADT/SmallVector.h"
52#include "llvm/Support/Casting.h"
53#include "llvm/Support/Compiler.h"
54#include "llvm/Support/ErrorHandling.h"
55#include <algorithm>
56#include <cassert>
57#include <tuple>
58#include <utility>
59
60namespace clang {
61
62 /// Various flags that control template argument deduction.
63 ///
64 /// These flags can be bitwise-OR'd together.
65 enum TemplateDeductionFlags {
66 /// No template argument deduction flags, which indicates the
67 /// strictest results for template argument deduction (as used for, e.g.,
68 /// matching class template partial specializations).
69 TDF_None = 0,
70
71 /// Within template argument deduction from a function call, we are
72 /// matching with a parameter type for which the original parameter was
73 /// a reference.
74 TDF_ParamWithReferenceType = 0x1,
75
76 /// Within template argument deduction from a function call, we
77 /// are matching in a case where we ignore cv-qualifiers.
78 TDF_IgnoreQualifiers = 0x02,
79
80 /// Within template argument deduction from a function call,
81 /// we are matching in a case where we can perform template argument
82 /// deduction from a template-id of a derived class of the argument type.
83 TDF_DerivedClass = 0x04,
84
85 /// Allow non-dependent types to differ, e.g., when performing
86 /// template argument deduction from a function call where conversions
87 /// may apply.
88 TDF_SkipNonDependent = 0x08,
89
90 /// Whether we are performing template argument deduction for
91 /// parameters and arguments in a top-level template argument
92 TDF_TopLevelParameterTypeList = 0x10,
93
94 /// Within template argument deduction from overload resolution per
95 /// C++ [over.over] allow matching function types that are compatible in
96 /// terms of noreturn and default calling convention adjustments, or
97 /// similarly matching a declared template specialization against a
98 /// possible template, per C++ [temp.deduct.decl]. In either case, permit
99 /// deduction where the parameter is a function type that can be converted
100 /// to the argument type.
101 TDF_AllowCompatibleFunctionType = 0x20,
102
103 /// Within template argument deduction for a conversion function, we are
104 /// matching with an argument type for which the original argument was
105 /// a reference.
106 TDF_ArgWithReferenceType = 0x40,
107 };
108}
109
110using namespace clang;
111using namespace sema;
112
113/// Compare two APSInts, extending and switching the sign as
114/// necessary to compare their values regardless of underlying type.
115static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) {
116 if (Y.getBitWidth() > X.getBitWidth())
117 X = X.extend(Y.getBitWidth());
118 else if (Y.getBitWidth() < X.getBitWidth())
119 Y = Y.extend(X.getBitWidth());
120
121 // If there is a signedness mismatch, correct it.
122 if (X.isSigned() != Y.isSigned()) {
123 // If the signed value is negative, then the values cannot be the same.
124 if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative()))
125 return false;
126
127 Y.setIsSigned(true);
128 X.setIsSigned(true);
129 }
130
131 return X == Y;
132}
133
134static Sema::TemplateDeductionResult
135DeduceTemplateArguments(Sema &S,
136 TemplateParameterList *TemplateParams,
137 const TemplateArgument &Param,
138 TemplateArgument Arg,
139 TemplateDeductionInfo &Info,
140 SmallVectorImpl<DeducedTemplateArgument> &Deduced);
141
142static Sema::TemplateDeductionResult
143DeduceTemplateArgumentsByTypeMatch(Sema &S,
144 TemplateParameterList *TemplateParams,
145 QualType Param,
146 QualType Arg,
147 TemplateDeductionInfo &Info,
148 SmallVectorImpl<DeducedTemplateArgument> &
149 Deduced,
150 unsigned TDF,
151 bool PartialOrdering = false,
152 bool DeducedFromArrayBound = false);
153
154static Sema::TemplateDeductionResult
155DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
156 ArrayRef<TemplateArgument> Params,
157 ArrayRef<TemplateArgument> Args,
158 TemplateDeductionInfo &Info,
159 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
160 bool NumberOfArgumentsMustMatch);
161
162static void MarkUsedTemplateParameters(ASTContext &Ctx,
163 const TemplateArgument &TemplateArg,
164 bool OnlyDeduced, unsigned Depth,
165 llvm::SmallBitVector &Used);
166
167static void MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
168 bool OnlyDeduced, unsigned Level,
169 llvm::SmallBitVector &Deduced);
170
171/// If the given expression is of a form that permits the deduction
172/// of a non-type template parameter, return the declaration of that
173/// non-type template parameter.
174static const NonTypeTemplateParmDecl *
175getDeducedParameterFromExpr(const Expr *E, unsigned Depth) {
176 // If we are within an alias template, the expression may have undergone
177 // any number of parameter substitutions already.
178 while (true) {
179 if (const auto *IC = dyn_cast<ImplicitCastExpr>(E))
180 E = IC->getSubExpr();
181 else if (const auto *CE = dyn_cast<ConstantExpr>(E))
182 E = CE->getSubExpr();
183 else if (const auto *Subst = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
184 E = Subst->getReplacement();
185 else if (const auto *CCE = dyn_cast<CXXConstructExpr>(E)) {
186 // Look through implicit copy construction from an lvalue of the same type.
187 if (CCE->getParenOrBraceRange().isValid())
188 break;
189 // Note, there could be default arguments.
190 assert(CCE->getNumArgs() >= 1 && "implicit construct expr should have 1 arg")((void)0);
191 E = CCE->getArg(0);
192 } else
193 break;
194 }
195
196 if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
197 if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()))
198 if (NTTP->getDepth() == Depth)
199 return NTTP;
200
201 return nullptr;
202}
203
204static const NonTypeTemplateParmDecl *
205getDeducedParameterFromExpr(TemplateDeductionInfo &Info, Expr *E) {
206 return getDeducedParameterFromExpr(E, Info.getDeducedDepth());
207}
208
209/// Determine whether two declaration pointers refer to the same
210/// declaration.
211static bool isSameDeclaration(Decl *X, Decl *Y) {
212 if (NamedDecl *NX = dyn_cast<NamedDecl>(X))
213 X = NX->getUnderlyingDecl();
214 if (NamedDecl *NY = dyn_cast<NamedDecl>(Y))
215 Y = NY->getUnderlyingDecl();
216
217 return X->getCanonicalDecl() == Y->getCanonicalDecl();
218}
219
220/// Verify that the given, deduced template arguments are compatible.
221///
222/// \returns The deduced template argument, or a NULL template argument if
223/// the deduced template arguments were incompatible.
224static DeducedTemplateArgument
225checkDeducedTemplateArguments(ASTContext &Context,
226 const DeducedTemplateArgument &X,
227 const DeducedTemplateArgument &Y) {
228 // We have no deduction for one or both of the arguments; they're compatible.
229 if (X.isNull())
230 return Y;
231 if (Y.isNull())
232 return X;
233
234 // If we have two non-type template argument values deduced for the same
235 // parameter, they must both match the type of the parameter, and thus must
236 // match each other's type. As we're only keeping one of them, we must check
237 // for that now. The exception is that if either was deduced from an array
238 // bound, the type is permitted to differ.
239 if (!X.wasDeducedFromArrayBound() && !Y.wasDeducedFromArrayBound()) {
240 QualType XType = X.getNonTypeTemplateArgumentType();
241 if (!XType.isNull()) {
242 QualType YType = Y.getNonTypeTemplateArgumentType();
243 if (YType.isNull() || !Context.hasSameType(XType, YType))
244 return DeducedTemplateArgument();
245 }
246 }
247
248 switch (X.getKind()) {
249 case TemplateArgument::Null:
250 llvm_unreachable("Non-deduced template arguments handled above")__builtin_unreachable();
251
252 case TemplateArgument::Type:
253 // If two template type arguments have the same type, they're compatible.
254 if (Y.getKind() == TemplateArgument::Type &&
255 Context.hasSameType(X.getAsType(), Y.getAsType()))
256 return X;
257
258 // If one of the two arguments was deduced from an array bound, the other
259 // supersedes it.
260 if (X.wasDeducedFromArrayBound() != Y.wasDeducedFromArrayBound())
261 return X.wasDeducedFromArrayBound() ? Y : X;
262
263 // The arguments are not compatible.
264 return DeducedTemplateArgument();
265
266 case TemplateArgument::Integral:
267 // If we deduced a constant in one case and either a dependent expression or
268 // declaration in another case, keep the integral constant.
269 // If both are integral constants with the same value, keep that value.
270 if (Y.getKind() == TemplateArgument::Expression ||
271 Y.getKind() == TemplateArgument::Declaration ||
272 (Y.getKind() == TemplateArgument::Integral &&
273 hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
274 return X.wasDeducedFromArrayBound() ? Y : X;
275
276 // All other combinations are incompatible.
277 return DeducedTemplateArgument();
278
279 case TemplateArgument::Template:
280 if (Y.getKind() == TemplateArgument::Template &&
281 Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate()))
282 return X;
283
284 // All other combinations are incompatible.
285 return DeducedTemplateArgument();
286
287 case TemplateArgument::TemplateExpansion:
288 if (Y.getKind() == TemplateArgument::TemplateExpansion &&
289 Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(),
290 Y.getAsTemplateOrTemplatePattern()))
291 return X;
292
293 // All other combinations are incompatible.
294 return DeducedTemplateArgument();
295
296 case TemplateArgument::Expression: {
297 if (Y.getKind() != TemplateArgument::Expression)
298 return checkDeducedTemplateArguments(Context, Y, X);
299
300 // Compare the expressions for equality
301 llvm::FoldingSetNodeID ID1, ID2;
302 X.getAsExpr()->Profile(ID1, Context, true);
303 Y.getAsExpr()->Profile(ID2, Context, true);
304 if (ID1 == ID2)
305 return X.wasDeducedFromArrayBound() ? Y : X;
306
307 // Differing dependent expressions are incompatible.
308 return DeducedTemplateArgument();
309 }
310
311 case TemplateArgument::Declaration:
312 assert(!X.wasDeducedFromArrayBound())((void)0);
313
314 // If we deduced a declaration and a dependent expression, keep the
315 // declaration.
316 if (Y.getKind() == TemplateArgument::Expression)
317 return X;
318
319 // If we deduced a declaration and an integral constant, keep the
320 // integral constant and whichever type did not come from an array
321 // bound.
322 if (Y.getKind() == TemplateArgument::Integral) {
323 if (Y.wasDeducedFromArrayBound())
324 return TemplateArgument(Context, Y.getAsIntegral(),
325 X.getParamTypeForDecl());
326 return Y;
327 }
328
329 // If we deduced two declarations, make sure that they refer to the
330 // same declaration.
331 if (Y.getKind() == TemplateArgument::Declaration &&
332 isSameDeclaration(X.getAsDecl(), Y.getAsDecl()))
333 return X;
334
335 // All other combinations are incompatible.
336 return DeducedTemplateArgument();
337
338 case TemplateArgument::NullPtr:
339 // If we deduced a null pointer and a dependent expression, keep the
340 // null pointer.
341 if (Y.getKind() == TemplateArgument::Expression)
342 return X;
343
344 // If we deduced a null pointer and an integral constant, keep the
345 // integral constant.
346 if (Y.getKind() == TemplateArgument::Integral)
347 return Y;
348
349 // If we deduced two null pointers, they are the same.
350 if (Y.getKind() == TemplateArgument::NullPtr)
351 return X;
352
353 // All other combinations are incompatible.
354 return DeducedTemplateArgument();
355
356 case TemplateArgument::Pack: {
357 if (Y.getKind() != TemplateArgument::Pack ||
358 X.pack_size() != Y.pack_size())
359 return DeducedTemplateArgument();
360
361 llvm::SmallVector<TemplateArgument, 8> NewPack;
362 for (TemplateArgument::pack_iterator XA = X.pack_begin(),
363 XAEnd = X.pack_end(),
364 YA = Y.pack_begin();
365 XA != XAEnd; ++XA, ++YA) {
366 TemplateArgument Merged = checkDeducedTemplateArguments(
367 Context, DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()),
368 DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound()));
369 if (Merged.isNull() && !(XA->isNull() && YA->isNull()))
370 return DeducedTemplateArgument();
371 NewPack.push_back(Merged);
372 }
373
374 return DeducedTemplateArgument(
375 TemplateArgument::CreatePackCopy(Context, NewPack),
376 X.wasDeducedFromArrayBound() && Y.wasDeducedFromArrayBound());
377 }
378 }
379
380 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable();
381}
382
383/// Deduce the value of the given non-type template parameter
384/// as the given deduced template argument. All non-type template parameter
385/// deduction is funneled through here.
386static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
387 Sema &S, TemplateParameterList *TemplateParams,
388 const NonTypeTemplateParmDecl *NTTP, const DeducedTemplateArgument &NewDeduced,
389 QualType ValueType, TemplateDeductionInfo &Info,
390 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
391 assert(NTTP->getDepth() == Info.getDeducedDepth() &&((void)0)
392 "deducing non-type template argument with wrong depth")((void)0);
393
394 DeducedTemplateArgument Result = checkDeducedTemplateArguments(
395 S.Context, Deduced[NTTP->getIndex()], NewDeduced);
396 if (Result.isNull()) {
397 Info.Param = const_cast<NonTypeTemplateParmDecl*>(NTTP);
398 Info.FirstArg = Deduced[NTTP->getIndex()];
399 Info.SecondArg = NewDeduced;
400 return Sema::TDK_Inconsistent;
401 }
402
403 Deduced[NTTP->getIndex()] = Result;
404 if (!S.getLangOpts().CPlusPlus17)
405 return Sema::TDK_Success;
406
407 if (NTTP->isExpandedParameterPack())
408 // FIXME: We may still need to deduce parts of the type here! But we
409 // don't have any way to find which slice of the type to use, and the
410 // type stored on the NTTP itself is nonsense. Perhaps the type of an
411 // expanded NTTP should be a pack expansion type?
412 return Sema::TDK_Success;
413
414 // Get the type of the parameter for deduction. If it's a (dependent) array
415 // or function type, we will not have decayed it yet, so do that now.
416 QualType ParamType = S.Context.getAdjustedParameterType(NTTP->getType());
417 if (auto *Expansion = dyn_cast<PackExpansionType>(ParamType))
418 ParamType = Expansion->getPattern();
419
420 // FIXME: It's not clear how deduction of a parameter of reference
421 // type from an argument (of non-reference type) should be performed.
422 // For now, we just remove reference types from both sides and let
423 // the final check for matching types sort out the mess.
424 ValueType = ValueType.getNonReferenceType();
425 if (ParamType->isReferenceType())
426 ParamType = ParamType.getNonReferenceType();
427 else
428 // Top-level cv-qualifiers are irrelevant for a non-reference type.
429 ValueType = ValueType.getUnqualifiedType();
430
431 return DeduceTemplateArgumentsByTypeMatch(
432 S, TemplateParams, ParamType, ValueType, Info, Deduced,
433 TDF_SkipNonDependent, /*PartialOrdering=*/false,
434 /*ArrayBound=*/NewDeduced.wasDeducedFromArrayBound());
435}
436
437/// Deduce the value of the given non-type template parameter
438/// from the given integral constant.
439static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
440 Sema &S, TemplateParameterList *TemplateParams,
441 const NonTypeTemplateParmDecl *NTTP, const llvm::APSInt &Value,
442 QualType ValueType, bool DeducedFromArrayBound, TemplateDeductionInfo &Info,
443 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
444 return DeduceNonTypeTemplateArgument(
445 S, TemplateParams, NTTP,
446 DeducedTemplateArgument(S.Context, Value, ValueType,
447 DeducedFromArrayBound),
448 ValueType, Info, Deduced);
449}
450
451/// Deduce the value of the given non-type template parameter
452/// from the given null pointer template argument type.
453static Sema::TemplateDeductionResult DeduceNullPtrTemplateArgument(
454 Sema &S, TemplateParameterList *TemplateParams,
455 const NonTypeTemplateParmDecl *NTTP, QualType NullPtrType,
456 TemplateDeductionInfo &Info,
457 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
458 Expr *Value = S.ImpCastExprToType(
459 new (S.Context) CXXNullPtrLiteralExpr(S.Context.NullPtrTy,
460 NTTP->getLocation()),
461 NullPtrType,
462 NullPtrType->isMemberPointerType() ? CK_NullToMemberPointer
463 : CK_NullToPointer)
464 .get();
465 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
466 DeducedTemplateArgument(Value),
467 Value->getType(), Info, Deduced);
468}
469
470/// Deduce the value of the given non-type template parameter
471/// from the given type- or value-dependent expression.
472///
473/// \returns true if deduction succeeded, false otherwise.
474static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
475 Sema &S, TemplateParameterList *TemplateParams,
476 const NonTypeTemplateParmDecl *NTTP, Expr *Value, TemplateDeductionInfo &Info,
477 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
478 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
479 DeducedTemplateArgument(Value),
480 Value->getType(), Info, Deduced);
481}
482
483/// Deduce the value of the given non-type template parameter
484/// from the given declaration.
485///
486/// \returns true if deduction succeeded, false otherwise.
487static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
488 Sema &S, TemplateParameterList *TemplateParams,
489 const NonTypeTemplateParmDecl *NTTP, ValueDecl *D, QualType T,
490 TemplateDeductionInfo &Info,
491 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
492 D = D ? cast<ValueDecl>(D->getCanonicalDecl()) : nullptr;
493 TemplateArgument New(D, T);
494 return DeduceNonTypeTemplateArgument(
495 S, TemplateParams, NTTP, DeducedTemplateArgument(New), T, Info, Deduced);
496}
497
498static Sema::TemplateDeductionResult
499DeduceTemplateArguments(Sema &S,
500 TemplateParameterList *TemplateParams,
501 TemplateName Param,
502 TemplateName Arg,
503 TemplateDeductionInfo &Info,
504 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
505 TemplateDecl *ParamDecl = Param.getAsTemplateDecl();
506 if (!ParamDecl) {
507 // The parameter type is dependent and is not a template template parameter,
508 // so there is nothing that we can deduce.
509 return Sema::TDK_Success;
510 }
511
512 if (TemplateTemplateParmDecl *TempParam
513 = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) {
514 // If we're not deducing at this depth, there's nothing to deduce.
515 if (TempParam->getDepth() != Info.getDeducedDepth())
516 return Sema::TDK_Success;
517
518 DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg));
519 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
520 Deduced[TempParam->getIndex()],
521 NewDeduced);
522 if (Result.isNull()) {
523 Info.Param = TempParam;
524 Info.FirstArg = Deduced[TempParam->getIndex()];
525 Info.SecondArg = NewDeduced;
526 return Sema::TDK_Inconsistent;
527 }
528
529 Deduced[TempParam->getIndex()] = Result;
530 return Sema::TDK_Success;
531 }
532
533 // Verify that the two template names are equivalent.
534 if (S.Context.hasSameTemplateName(Param, Arg))
535 return Sema::TDK_Success;
536
537 // Mismatch of non-dependent template parameter to argument.
538 Info.FirstArg = TemplateArgument(Param);
539 Info.SecondArg = TemplateArgument(Arg);
540 return Sema::TDK_NonDeducedMismatch;
541}
542
543/// Deduce the template arguments by comparing the template parameter
544/// type (which is a template-id) with the template argument type.
545///
546/// \param S the Sema
547///
548/// \param TemplateParams the template parameters that we are deducing
549///
550/// \param Param the parameter type
551///
552/// \param Arg the argument type
553///
554/// \param Info information about the template argument deduction itself
555///
556/// \param Deduced the deduced template arguments
557///
558/// \returns the result of template argument deduction so far. Note that a
559/// "success" result means that template argument deduction has not yet failed,
560/// but it may still fail, later, for other reasons.
561static Sema::TemplateDeductionResult
562DeduceTemplateArguments(Sema &S,
563 TemplateParameterList *TemplateParams,
564 const TemplateSpecializationType *Param,
565 QualType Arg,
566 TemplateDeductionInfo &Info,
567 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
568 assert(Arg.isCanonical() && "Argument type must be canonical")((void)0);
569
570 // Treat an injected-class-name as its underlying template-id.
571 if (auto *Injected = dyn_cast<InjectedClassNameType>(Arg))
572 Arg = Injected->getInjectedSpecializationType();
573
574 // Check whether the template argument is a dependent template-id.
575 if (const TemplateSpecializationType *SpecArg
576 = dyn_cast<TemplateSpecializationType>(Arg)) {
577 // Perform template argument deduction for the template name.
578 if (Sema::TemplateDeductionResult Result
579 = DeduceTemplateArguments(S, TemplateParams,
580 Param->getTemplateName(),
581 SpecArg->getTemplateName(),
582 Info, Deduced))
583 return Result;
584
585
586 // Perform template argument deduction on each template
587 // argument. Ignore any missing/extra arguments, since they could be
588 // filled in by default arguments.
589 return DeduceTemplateArguments(S, TemplateParams,
590 Param->template_arguments(),
591 SpecArg->template_arguments(), Info, Deduced,
592 /*NumberOfArgumentsMustMatch=*/false);
593 }
594
595 // If the argument type is a class template specialization, we
596 // perform template argument deduction using its template
597 // arguments.
598 const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
599 if (!RecordArg) {
600 Info.FirstArg = TemplateArgument(QualType(Param, 0));
601 Info.SecondArg = TemplateArgument(Arg);
602 return Sema::TDK_NonDeducedMismatch;
603 }
604
605 ClassTemplateSpecializationDecl *SpecArg
606 = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
607 if (!SpecArg) {
608 Info.FirstArg = TemplateArgument(QualType(Param, 0));
609 Info.SecondArg = TemplateArgument(Arg);
610 return Sema::TDK_NonDeducedMismatch;
611 }
612
613 // Perform template argument deduction for the template name.
614 if (Sema::TemplateDeductionResult Result
615 = DeduceTemplateArguments(S,
616 TemplateParams,
617 Param->getTemplateName(),
618 TemplateName(SpecArg->getSpecializedTemplate()),
619 Info, Deduced))
620 return Result;
621
622 // Perform template argument deduction for the template arguments.
623 return DeduceTemplateArguments(S, TemplateParams, Param->template_arguments(),
624 SpecArg->getTemplateArgs().asArray(), Info,
625 Deduced, /*NumberOfArgumentsMustMatch=*/true);
626}
627
628/// Determines whether the given type is an opaque type that
629/// might be more qualified when instantiated.
630static bool IsPossiblyOpaquelyQualifiedType(QualType T) {
631 switch (T->getTypeClass()) {
632 case Type::TypeOfExpr:
633 case Type::TypeOf:
634 case Type::DependentName:
635 case Type::Decltype:
636 case Type::UnresolvedUsing:
637 case Type::TemplateTypeParm:
638 return true;
639
640 case Type::ConstantArray:
641 case Type::IncompleteArray:
642 case Type::VariableArray:
643 case Type::DependentSizedArray:
644 return IsPossiblyOpaquelyQualifiedType(
645 cast<ArrayType>(T)->getElementType());
646
647 default:
648 return false;
649 }
650}
651
652/// Helper function to build a TemplateParameter when we don't
653/// know its type statically.
654static TemplateParameter makeTemplateParameter(Decl *D) {
655 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D))
656 return TemplateParameter(TTP);
657 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D))
658 return TemplateParameter(NTTP);
659
660 return TemplateParameter(cast<TemplateTemplateParmDecl>(D));
661}
662
663/// A pack that we're currently deducing.
664struct clang::DeducedPack {
665 // The index of the pack.
666 unsigned Index;
667
668 // The old value of the pack before we started deducing it.
669 DeducedTemplateArgument Saved;
670
671 // A deferred value of this pack from an inner deduction, that couldn't be
672 // deduced because this deduction hadn't happened yet.
673 DeducedTemplateArgument DeferredDeduction;
674
675 // The new value of the pack.
676 SmallVector<DeducedTemplateArgument, 4> New;
677
678 // The outer deduction for this pack, if any.
679 DeducedPack *Outer = nullptr;
680
681 DeducedPack(unsigned Index) : Index(Index) {}
682};
683
684namespace {
685
686/// A scope in which we're performing pack deduction.
687class PackDeductionScope {
688public:
689 /// Prepare to deduce the packs named within Pattern.
690 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
691 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
692 TemplateDeductionInfo &Info, TemplateArgument Pattern)
693 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
694 unsigned NumNamedPacks = addPacks(Pattern);
695 finishConstruction(NumNamedPacks);
696 }
697
698 /// Prepare to directly deduce arguments of the parameter with index \p Index.
699 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
700 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
701 TemplateDeductionInfo &Info, unsigned Index)
702 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
703 addPack(Index);
704 finishConstruction(1);
705 }
706
707private:
708 void addPack(unsigned Index) {
709 // Save the deduced template argument for the parameter pack expanded
710 // by this pack expansion, then clear out the deduction.
711 DeducedPack Pack(Index);
712 Pack.Saved = Deduced[Index];
713 Deduced[Index] = TemplateArgument();
714
715 // FIXME: What if we encounter multiple packs with different numbers of
716 // pre-expanded expansions? (This should already have been diagnosed
717 // during substitution.)
718 if (Optional<unsigned> ExpandedPackExpansions =
719 getExpandedPackSize(TemplateParams->getParam(Index)))
720 FixedNumExpansions = ExpandedPackExpansions;
721
722 Packs.push_back(Pack);
723 }
724
725 unsigned addPacks(TemplateArgument Pattern) {
726 // Compute the set of template parameter indices that correspond to
727 // parameter packs expanded by the pack expansion.
728 llvm::SmallBitVector SawIndices(TemplateParams->size());
729 llvm::SmallVector<TemplateArgument, 4> ExtraDeductions;
730
731 auto AddPack = [&](unsigned Index) {
732 if (SawIndices[Index])
733 return;
734 SawIndices[Index] = true;
735 addPack(Index);
736
737 // Deducing a parameter pack that is a pack expansion also constrains the
738 // packs appearing in that parameter to have the same deduced arity. Also,
739 // in C++17 onwards, deducing a non-type template parameter deduces its
740 // type, so we need to collect the pending deduced values for those packs.
741 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(
742 TemplateParams->getParam(Index))) {
743 if (!NTTP->isExpandedParameterPack())
744 if (auto *Expansion = dyn_cast<PackExpansionType>(NTTP->getType()))
745 ExtraDeductions.push_back(Expansion->getPattern());
746 }
747 // FIXME: Also collect the unexpanded packs in any type and template
748 // parameter packs that are pack expansions.
749 };
750
751 auto Collect = [&](TemplateArgument Pattern) {
752 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
753 S.collectUnexpandedParameterPacks(Pattern, Unexpanded);
754 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
755 unsigned Depth, Index;
756 std::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]);
757 if (Depth == Info.getDeducedDepth())
758 AddPack(Index);
759 }
760 };
761
762 // Look for unexpanded packs in the pattern.
763 Collect(Pattern);
764 assert(!Packs.empty() && "Pack expansion without unexpanded packs?")((void)0);
765
766 unsigned NumNamedPacks = Packs.size();
767
768 // Also look for unexpanded packs that are indirectly deduced by deducing
769 // the sizes of the packs in this pattern.
770 while (!ExtraDeductions.empty())
771 Collect(ExtraDeductions.pop_back_val());
772
773 return NumNamedPacks;
774 }
775
776 void finishConstruction(unsigned NumNamedPacks) {
777 // Dig out the partially-substituted pack, if there is one.
778 const TemplateArgument *PartialPackArgs = nullptr;
779 unsigned NumPartialPackArgs = 0;
780 std::pair<unsigned, unsigned> PartialPackDepthIndex(-1u, -1u);
781 if (auto *Scope = S.CurrentInstantiationScope)
782 if (auto *Partial = Scope->getPartiallySubstitutedPack(
783 &PartialPackArgs, &NumPartialPackArgs))
784 PartialPackDepthIndex = getDepthAndIndex(Partial);
785
786 // This pack expansion will have been partially or fully expanded if
787 // it only names explicitly-specified parameter packs (including the
788 // partially-substituted one, if any).
789 bool IsExpanded = true;
790 for (unsigned I = 0; I != NumNamedPacks; ++I) {
791 if (Packs[I].Index >= Info.getNumExplicitArgs()) {
792 IsExpanded = false;
793 IsPartiallyExpanded = false;
794 break;
795 }
796 if (PartialPackDepthIndex ==
797 std::make_pair(Info.getDeducedDepth(), Packs[I].Index)) {
798 IsPartiallyExpanded = true;
799 }
800 }
801
802 // Skip over the pack elements that were expanded into separate arguments.
803 // If we partially expanded, this is the number of partial arguments.
804 if (IsPartiallyExpanded)
805 PackElements += NumPartialPackArgs;
806 else if (IsExpanded)
807 PackElements += *FixedNumExpansions;
808
809 for (auto &Pack : Packs) {
810 if (Info.PendingDeducedPacks.size() > Pack.Index)
811 Pack.Outer = Info.PendingDeducedPacks[Pack.Index];
812 else
813 Info.PendingDeducedPacks.resize(Pack.Index + 1);
814 Info.PendingDeducedPacks[Pack.Index] = &Pack;
815
816 if (PartialPackDepthIndex ==
817 std::make_pair(Info.getDeducedDepth(), Pack.Index)) {
818 Pack.New.append(PartialPackArgs, PartialPackArgs + NumPartialPackArgs);
819 // We pre-populate the deduced value of the partially-substituted
820 // pack with the specified value. This is not entirely correct: the
821 // value is supposed to have been substituted, not deduced, but the
822 // cases where this is observable require an exact type match anyway.
823 //
824 // FIXME: If we could represent a "depth i, index j, pack elem k"
825 // parameter, we could substitute the partially-substituted pack
826 // everywhere and avoid this.
827 if (!IsPartiallyExpanded)
828 Deduced[Pack.Index] = Pack.New[PackElements];
829 }
830 }
831 }
832
833public:
834 ~PackDeductionScope() {
835 for (auto &Pack : Packs)
836 Info.PendingDeducedPacks[Pack.Index] = Pack.Outer;
837 }
838
839 /// Determine whether this pack has already been partially expanded into a
840 /// sequence of (prior) function parameters / template arguments.
841 bool isPartiallyExpanded() { return IsPartiallyExpanded; }
842
843 /// Determine whether this pack expansion scope has a known, fixed arity.
844 /// This happens if it involves a pack from an outer template that has
845 /// (notionally) already been expanded.
846 bool hasFixedArity() { return FixedNumExpansions.hasValue(); }
847
848 /// Determine whether the next element of the argument is still part of this
849 /// pack. This is the case unless the pack is already expanded to a fixed
850 /// length.
851 bool hasNextElement() {
852 return !FixedNumExpansions || *FixedNumExpansions > PackElements;
853 }
854
855 /// Move to deducing the next element in each pack that is being deduced.
856 void nextPackElement() {
857 // Capture the deduced template arguments for each parameter pack expanded
858 // by this pack expansion, add them to the list of arguments we've deduced
859 // for that pack, then clear out the deduced argument.
860 for (auto &Pack : Packs) {
861 DeducedTemplateArgument &DeducedArg = Deduced[Pack.Index];
862 if (!Pack.New.empty() || !DeducedArg.isNull()) {
863 while (Pack.New.size() < PackElements)
864 Pack.New.push_back(DeducedTemplateArgument());
865 if (Pack.New.size() == PackElements)
866 Pack.New.push_back(DeducedArg);
867 else
868 Pack.New[PackElements] = DeducedArg;
869 DeducedArg = Pack.New.size() > PackElements + 1
870 ? Pack.New[PackElements + 1]
871 : DeducedTemplateArgument();
872 }
873 }
874 ++PackElements;
875 }
876
877 /// Finish template argument deduction for a set of argument packs,
878 /// producing the argument packs and checking for consistency with prior
879 /// deductions.
880 Sema::TemplateDeductionResult finish() {
881 // Build argument packs for each of the parameter packs expanded by this
882 // pack expansion.
883 for (auto &Pack : Packs) {
884 // Put back the old value for this pack.
885 Deduced[Pack.Index] = Pack.Saved;
886
887 // Always make sure the size of this pack is correct, even if we didn't
888 // deduce any values for it.
889 //
890 // FIXME: This isn't required by the normative wording, but substitution
891 // and post-substitution checking will always fail if the arity of any
892 // pack is not equal to the number of elements we processed. (Either that
893 // or something else has gone *very* wrong.) We're permitted to skip any
894 // hard errors from those follow-on steps by the intent (but not the
895 // wording) of C++ [temp.inst]p8:
896 //
897 // If the function selected by overload resolution can be determined
898 // without instantiating a class template definition, it is unspecified
899 // whether that instantiation actually takes place
900 Pack.New.resize(PackElements);
901
902 // Build or find a new value for this pack.
903 DeducedTemplateArgument NewPack;
904 if (Pack.New.empty()) {
905 // If we deduced an empty argument pack, create it now.
906 NewPack = DeducedTemplateArgument(TemplateArgument::getEmptyPack());
907 } else {
908 TemplateArgument *ArgumentPack =
909 new (S.Context) TemplateArgument[Pack.New.size()];
910 std::copy(Pack.New.begin(), Pack.New.end(), ArgumentPack);
911 NewPack = DeducedTemplateArgument(
912 TemplateArgument(llvm::makeArrayRef(ArgumentPack, Pack.New.size())),
913 // FIXME: This is wrong, it's possible that some pack elements are
914 // deduced from an array bound and others are not:
915 // template<typename ...T, T ...V> void g(const T (&...p)[V]);
916 // g({1, 2, 3}, {{}, {}});
917 // ... should deduce T = {int, size_t (from array bound)}.
918 Pack.New[0].wasDeducedFromArrayBound());
919 }
920
921 // Pick where we're going to put the merged pack.
922 DeducedTemplateArgument *Loc;
923 if (Pack.Outer) {
924 if (Pack.Outer->DeferredDeduction.isNull()) {
925 // Defer checking this pack until we have a complete pack to compare
926 // it against.
927 Pack.Outer->DeferredDeduction = NewPack;
928 continue;
929 }
930 Loc = &Pack.Outer->DeferredDeduction;
931 } else {
932 Loc = &Deduced[Pack.Index];
933 }
934
935 // Check the new pack matches any previous value.
936 DeducedTemplateArgument OldPack = *Loc;
937 DeducedTemplateArgument Result =
938 checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
939
940 // If we deferred a deduction of this pack, check that one now too.
941 if (!Result.isNull() && !Pack.DeferredDeduction.isNull()) {
942 OldPack = Result;
943 NewPack = Pack.DeferredDeduction;
944 Result = checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
945 }
946
947 NamedDecl *Param = TemplateParams->getParam(Pack.Index);
948 if (Result.isNull()) {
949 Info.Param = makeTemplateParameter(Param);
950 Info.FirstArg = OldPack;
951 Info.SecondArg = NewPack;
952 return Sema::TDK_Inconsistent;
953 }
954
955 // If we have a pre-expanded pack and we didn't deduce enough elements
956 // for it, fail deduction.
957 if (Optional<unsigned> Expansions = getExpandedPackSize(Param)) {
958 if (*Expansions != PackElements) {
959 Info.Param = makeTemplateParameter(Param);
960 Info.FirstArg = Result;
961 return Sema::TDK_IncompletePack;
962 }
963 }
964
965 *Loc = Result;
966 }
967
968 return Sema::TDK_Success;
969 }
970
971private:
972 Sema &S;
973 TemplateParameterList *TemplateParams;
974 SmallVectorImpl<DeducedTemplateArgument> &Deduced;
975 TemplateDeductionInfo &Info;
976 unsigned PackElements = 0;
977 bool IsPartiallyExpanded = false;
978 /// The number of expansions, if we have a fully-expanded pack in this scope.
979 Optional<unsigned> FixedNumExpansions;
980
981 SmallVector<DeducedPack, 2> Packs;
982};
983
984} // namespace
985
986/// Deduce the template arguments by comparing the list of parameter
987/// types to the list of argument types, as in the parameter-type-lists of
988/// function types (C++ [temp.deduct.type]p10).
989///
990/// \param S The semantic analysis object within which we are deducing
991///
992/// \param TemplateParams The template parameters that we are deducing
993///
994/// \param Params The list of parameter types
995///
996/// \param NumParams The number of types in \c Params
997///
998/// \param Args The list of argument types
999///
1000/// \param NumArgs The number of types in \c Args
1001///
1002/// \param Info information about the template argument deduction itself
1003///
1004/// \param Deduced the deduced template arguments
1005///
1006/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
1007/// how template argument deduction is performed.
1008///
1009/// \param PartialOrdering If true, we are performing template argument
1010/// deduction for during partial ordering for a call
1011/// (C++0x [temp.deduct.partial]).
1012///
1013/// \returns the result of template argument deduction so far. Note that a
1014/// "success" result means that template argument deduction has not yet failed,
1015/// but it may still fail, later, for other reasons.
1016static Sema::TemplateDeductionResult
1017DeduceTemplateArguments(Sema &S,
1018 TemplateParameterList *TemplateParams,
1019 const QualType *Params, unsigned NumParams,
1020 const QualType *Args, unsigned NumArgs,
1021 TemplateDeductionInfo &Info,
1022 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1023 unsigned TDF,
1024 bool PartialOrdering = false) {
1025 // C++0x [temp.deduct.type]p10:
1026 // Similarly, if P has a form that contains (T), then each parameter type
1027 // Pi of the respective parameter-type- list of P is compared with the
1028 // corresponding parameter type Ai of the corresponding parameter-type-list
1029 // of A. [...]
1030 unsigned ArgIdx = 0, ParamIdx = 0;
1031 for (; ParamIdx != NumParams; ++ParamIdx) {
1032 // Check argument types.
1033 const PackExpansionType *Expansion
1034 = dyn_cast<PackExpansionType>(Params[ParamIdx]);
1035 if (!Expansion) {
1036 // Simple case: compare the parameter and argument types at this point.
1037
1038 // Make sure we have an argument.
1039 if (ArgIdx >= NumArgs)
1040 return Sema::TDK_MiscellaneousDeductionFailure;
1041
1042 if (isa<PackExpansionType>(Args[ArgIdx])) {
1043 // C++0x [temp.deduct.type]p22:
1044 // If the original function parameter associated with A is a function
1045 // parameter pack and the function parameter associated with P is not
1046 // a function parameter pack, then template argument deduction fails.
1047 return Sema::TDK_MiscellaneousDeductionFailure;
1048 }
1049
1050 if (Sema::TemplateDeductionResult Result
1051 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1052 Params[ParamIdx], Args[ArgIdx],
1053 Info, Deduced, TDF,
1054 PartialOrdering))
1055 return Result;
1056
1057 ++ArgIdx;
1058 continue;
1059 }
1060
1061 // C++0x [temp.deduct.type]p10:
1062 // If the parameter-declaration corresponding to Pi is a function
1063 // parameter pack, then the type of its declarator- id is compared with
1064 // each remaining parameter type in the parameter-type-list of A. Each
1065 // comparison deduces template arguments for subsequent positions in the
1066 // template parameter packs expanded by the function parameter pack.
1067
1068 QualType Pattern = Expansion->getPattern();
1069 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
1070
1071 // A pack scope with fixed arity is not really a pack any more, so is not
1072 // a non-deduced context.
1073 if (ParamIdx + 1 == NumParams || PackScope.hasFixedArity()) {
1074 for (; ArgIdx < NumArgs && PackScope.hasNextElement(); ++ArgIdx) {
1075 // Deduce template arguments from the pattern.
1076 if (Sema::TemplateDeductionResult Result
1077 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern,
1078 Args[ArgIdx], Info, Deduced,
1079 TDF, PartialOrdering))
1080 return Result;
1081
1082 PackScope.nextPackElement();
1083 }
1084 } else {
1085 // C++0x [temp.deduct.type]p5:
1086 // The non-deduced contexts are:
1087 // - A function parameter pack that does not occur at the end of the
1088 // parameter-declaration-clause.
1089 //
1090 // FIXME: There is no wording to say what we should do in this case. We
1091 // choose to resolve this by applying the same rule that is applied for a
1092 // function call: that is, deduce all contained packs to their
1093 // explicitly-specified values (or to <> if there is no such value).
1094 //
1095 // This is seemingly-arbitrarily different from the case of a template-id
1096 // with a non-trailing pack-expansion in its arguments, which renders the
1097 // entire template-argument-list a non-deduced context.
1098
1099 // If the parameter type contains an explicitly-specified pack that we
1100 // could not expand, skip the number of parameters notionally created
1101 // by the expansion.
1102 Optional<unsigned> NumExpansions = Expansion->getNumExpansions();
1103 if (NumExpansions && !PackScope.isPartiallyExpanded()) {
1104 for (unsigned I = 0; I != *NumExpansions && ArgIdx < NumArgs;
1105 ++I, ++ArgIdx)
1106 PackScope.nextPackElement();
1107 }
1108 }
1109
1110 // Build argument packs for each of the parameter packs expanded by this
1111 // pack expansion.
1112 if (auto Result = PackScope.finish())
1113 return Result;
1114 }
1115
1116 // Make sure we don't have any extra arguments.
1117 if (ArgIdx < NumArgs)
1118 return Sema::TDK_MiscellaneousDeductionFailure;
1119
1120 return Sema::TDK_Success;
1121}
1122
1123/// Determine whether the parameter has qualifiers that the argument
1124/// lacks. Put another way, determine whether there is no way to add
1125/// a deduced set of qualifiers to the ParamType that would result in
1126/// its qualifiers matching those of the ArgType.
1127static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType,
1128 QualType ArgType) {
1129 Qualifiers ParamQs = ParamType.getQualifiers();
1130 Qualifiers ArgQs = ArgType.getQualifiers();
1131
1132 if (ParamQs == ArgQs)
1133 return false;
1134
1135 // Mismatched (but not missing) Objective-C GC attributes.
1136 if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() &&
1137 ParamQs.hasObjCGCAttr())
1138 return true;
1139
1140 // Mismatched (but not missing) address spaces.
1141 if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() &&
1142 ParamQs.hasAddressSpace())
1143 return true;
1144
1145 // Mismatched (but not missing) Objective-C lifetime qualifiers.
1146 if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() &&
1147 ParamQs.hasObjCLifetime())
1148 return true;
1149
1150 // CVR qualifiers inconsistent or a superset.
1151 return (ParamQs.getCVRQualifiers() & ~ArgQs.getCVRQualifiers()) != 0;
1152}
1153
1154/// Compare types for equality with respect to possibly compatible
1155/// function types (noreturn adjustment, implicit calling conventions). If any
1156/// of parameter and argument is not a function, just perform type comparison.
1157///
1158/// \param Param the template parameter type.
1159///
1160/// \param Arg the argument type.
1161bool Sema::isSameOrCompatibleFunctionType(CanQualType Param,
1162 CanQualType Arg) {
1163 const FunctionType *ParamFunction = Param->getAs<FunctionType>(),
1164 *ArgFunction = Arg->getAs<FunctionType>();
1165
1166 // Just compare if not functions.
1167 if (!ParamFunction || !ArgFunction)
1168 return Param == Arg;
1169
1170 // Noreturn and noexcept adjustment.
1171 QualType AdjustedParam;
1172 if (IsFunctionConversion(Param, Arg, AdjustedParam))
1173 return Arg == Context.getCanonicalType(AdjustedParam);
1174
1175 // FIXME: Compatible calling conventions.
1176
1177 return Param == Arg;
1178}
1179
1180/// Get the index of the first template parameter that was originally from the
1181/// innermost template-parameter-list. This is 0 except when we concatenate
1182/// the template parameter lists of a class template and a constructor template
1183/// when forming an implicit deduction guide.
1184static unsigned getFirstInnerIndex(FunctionTemplateDecl *FTD) {
1185 auto *Guide = dyn_cast<CXXDeductionGuideDecl>(FTD->getTemplatedDecl());
1186 if (!Guide || !Guide->isImplicit())
1187 return 0;
1188 return Guide->getDeducedTemplate()->getTemplateParameters()->size();
1189}
1190
1191/// Determine whether a type denotes a forwarding reference.
1192static bool isForwardingReference(QualType Param, unsigned FirstInnerIndex) {
1193 // C++1z [temp.deduct.call]p3:
1194 // A forwarding reference is an rvalue reference to a cv-unqualified
1195 // template parameter that does not represent a template parameter of a
1196 // class template.
1197 if (auto *ParamRef = Param->getAs<RValueReferenceType>()) {
1198 if (ParamRef->getPointeeType().getQualifiers())
1199 return false;
1200 auto *TypeParm = ParamRef->getPointeeType()->getAs<TemplateTypeParmType>();
1201 return TypeParm && TypeParm->getIndex() >= FirstInnerIndex;
1202 }
1203 return false;
1204}
1205
1206/// Attempt to deduce the template arguments by checking the base types
1207/// according to (C++20 [temp.deduct.call] p4b3.
1208///
1209/// \param S the semantic analysis object within which we are deducing.
1210///
1211/// \param RecordT the top level record object we are deducing against.
1212///
1213/// \param TemplateParams the template parameters that we are deducing.
1214///
1215/// \param SpecParam the template specialization parameter type.
1216///
1217/// \param Info information about the template argument deduction itself.
1218///
1219/// \param Deduced the deduced template arguments.
1220///
1221/// \returns the result of template argument deduction with the bases. "invalid"
1222/// means no matches, "success" found a single item, and the
1223/// "MiscellaneousDeductionFailure" result happens when the match is ambiguous.
1224static Sema::TemplateDeductionResult DeduceTemplateBases(
1225 Sema &S, const RecordType *RecordT, TemplateParameterList *TemplateParams,
1226 const TemplateSpecializationType *SpecParam, TemplateDeductionInfo &Info,
1227 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
1228 // C++14 [temp.deduct.call] p4b3:
1229 // If P is a class and P has the form simple-template-id, then the
1230 // transformed A can be a derived class of the deduced A. Likewise if
1231 // P is a pointer to a class of the form simple-template-id, the
1232 // transformed A can be a pointer to a derived class pointed to by the
1233 // deduced A. However, if there is a class C that is a (direct or
1234 // indirect) base class of D and derived (directly or indirectly) from a
1235 // class B and that would be a valid deduced A, the deduced A cannot be
1236 // B or pointer to B, respectively.
1237 //
1238 // These alternatives are considered only if type deduction would
1239 // otherwise fail. If they yield more than one possible deduced A, the
1240 // type deduction fails.
1241
1242 // Use a breadth-first search through the bases to collect the set of
1243 // successful matches. Visited contains the set of nodes we have already
1244 // visited, while ToVisit is our stack of records that we still need to
1245 // visit. Matches contains a list of matches that have yet to be
1246 // disqualified.
1247 llvm::SmallPtrSet<const RecordType *, 8> Visited;
1248 SmallVector<const RecordType *, 8> ToVisit;
1249 // We iterate over this later, so we have to use MapVector to ensure
1250 // determinism.
1251 llvm::MapVector<const RecordType *, SmallVector<DeducedTemplateArgument, 8>>
1252 Matches;
1253
1254 auto AddBases = [&Visited, &ToVisit](const RecordType *RT) {
1255 CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1256 for (const auto &Base : RD->bases()) {
1257 assert(Base.getType()->isRecordType() &&((void)0)
1258 "Base class that isn't a record?")((void)0);
1259 const RecordType *RT = Base.getType()->getAs<RecordType>();
1260 if (Visited.insert(RT).second)
1261 ToVisit.push_back(Base.getType()->getAs<RecordType>());
1262 }
1263 };
1264
1265 // Set up the loop by adding all the bases.
1266 AddBases(RecordT);
1267
1268 // Search each path of bases until we either run into a successful match
1269 // (where all bases of it are invalid), or we run out of bases.
1270 while (!ToVisit.empty()) {
1271 const RecordType *NextT = ToVisit.pop_back_val();
1272
1273 SmallVector<DeducedTemplateArgument, 8> DeducedCopy(Deduced.begin(),
1274 Deduced.end());
1275 TemplateDeductionInfo BaseInfo(TemplateDeductionInfo::ForBase, Info);
1276 Sema::TemplateDeductionResult BaseResult =
1277 DeduceTemplateArguments(S, TemplateParams, SpecParam,
1278 QualType(NextT, 0), BaseInfo, DeducedCopy);
1279
1280 // If this was a successful deduction, add it to the list of matches,
1281 // otherwise we need to continue searching its bases.
1282 if (BaseResult == Sema::TDK_Success)
1283 Matches.insert({NextT, DeducedCopy});
1284 else
1285 AddBases(NextT);
1286 }
1287
1288 // At this point, 'Matches' contains a list of seemingly valid bases, however
1289 // in the event that we have more than 1 match, it is possible that the base
1290 // of one of the matches might be disqualified for being a base of another
1291 // valid match. We can count on cyclical instantiations being invalid to
1292 // simplify the disqualifications. That is, if A & B are both matches, and B
1293 // inherits from A (disqualifying A), we know that A cannot inherit from B.
1294 if (Matches.size() > 1) {
1295 Visited.clear();
1296 for (const auto &Match : Matches)
1297 AddBases(Match.first);
1298
1299 // We can give up once we have a single item (or have run out of things to
1300 // search) since cyclical inheritence isn't valid.
1301 while (Matches.size() > 1 && !ToVisit.empty()) {
1302 const RecordType *NextT = ToVisit.pop_back_val();
1303 Matches.erase(NextT);
1304
1305 // Always add all bases, since the inheritence tree can contain
1306 // disqualifications for multiple matches.
1307 AddBases(NextT);
1308 }
1309 }
1310
1311 if (Matches.empty())
1312 return Sema::TDK_Invalid;
1313 if (Matches.size() > 1)
1314 return Sema::TDK_MiscellaneousDeductionFailure;
1315
1316 std::swap(Matches.front().second, Deduced);
1317 return Sema::TDK_Success;
1318}
1319
1320/// Deduce the template arguments by comparing the parameter type and
1321/// the argument type (C++ [temp.deduct.type]).
1322///
1323/// \param S the semantic analysis object within which we are deducing
1324///
1325/// \param TemplateParams the template parameters that we are deducing
1326///
1327/// \param ParamIn the parameter type
1328///
1329/// \param ArgIn the argument type
1330///
1331/// \param Info information about the template argument deduction itself
1332///
1333/// \param Deduced the deduced template arguments
1334///
1335/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
1336/// how template argument deduction is performed.
1337///
1338/// \param PartialOrdering Whether we're performing template argument deduction
1339/// in the context of partial ordering (C++0x [temp.deduct.partial]).
1340///
1341/// \returns the result of template argument deduction so far. Note that a
1342/// "success" result means that template argument deduction has not yet failed,
1343/// but it may still fail, later, for other reasons.
1344static Sema::TemplateDeductionResult
1345DeduceTemplateArgumentsByTypeMatch(Sema &S,
1346 TemplateParameterList *TemplateParams,
1347 QualType ParamIn, QualType ArgIn,
1348 TemplateDeductionInfo &Info,
1349 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1350 unsigned TDF,
1351 bool PartialOrdering,
1352 bool DeducedFromArrayBound) {
1353 // We only want to look at the canonical types, since typedefs and
1354 // sugar are not part of template argument deduction.
1355 QualType Param = S.Context.getCanonicalType(ParamIn);
1356 QualType Arg = S.Context.getCanonicalType(ArgIn);
1357
1358 // If the argument type is a pack expansion, look at its pattern.
1359 // This isn't explicitly called out
1360 if (const PackExpansionType *ArgExpansion
0.1
'ArgExpansion' is null
1
Taking false branch
→
1361 = dyn_cast<PackExpansionType>(Arg)) 1362 Arg = ArgExpansion->getPattern(); 1363 1364 if (PartialOrdering) {
2
←
Assuming 'PartialOrdering' is false
→
3
←
Taking false branch
→
1365 // C++11 [temp.deduct.partial]p5: 1366 // Before the partial ordering is done, certain transformations are 1367 // performed on the types used for partial ordering: 1368 // - If P is a reference type, P is replaced by the type referred to. 1369 const ReferenceType *ParamRef = Param->getAs<ReferenceType>(); 1370 if (ParamRef) 1371 Param = ParamRef->getPointeeType(); 1372 1373 // - If A is a reference type, A is replaced by the type referred to. 1374 const ReferenceType *ArgRef = Arg->getAs<ReferenceType>(); 1375 if (ArgRef) 1376 Arg = ArgRef->getPointeeType(); 1377 1378 if (ParamRef && ArgRef && S.Context.hasSameUnqualifiedType(Param, Arg)) { 1379 // C++11 [temp.deduct.partial]p9: 1380 // If, for a given type, deduction succeeds in both directions (i.e., 1381 // the types are identical after the transformations above) and both 1382 // P and A were reference types [...]: 1383 // - if [one type] was an lvalue reference and [the other type] was 1384 // not, [the other type] is not considered to be at least as 1385 // specialized as [the first type] 1386 // - if [one type] is more cv-qualified than [the other type], 1387 // [the other type] is not considered to be at least as specialized 1388 // as [the first type] 1389 // Objective-C ARC adds: 1390 // - [one type] has non-trivial lifetime, [the other type] has 1391 // __unsafe_unretained lifetime, and the types are otherwise 1392 // identical 1393 // 1394 // A is "considered to be at least as specialized" as P iff deduction 1395 // succeeds, so we model this as a deduction failure. Note that 1396 // [the first type] is P and [the other type] is A here; the standard 1397 // gets this backwards. 1398 Qualifiers ParamQuals = Param.getQualifiers(); 1399 Qualifiers ArgQuals = Arg.getQualifiers(); 1400 if ((ParamRef->isLValueReferenceType() && 1401 !ArgRef->isLValueReferenceType()) || 1402 ParamQuals.isStrictSupersetOf(ArgQuals) || 1403 (ParamQuals.hasNonTrivialObjCLifetime() && 1404 ArgQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone && 1405 ParamQuals.withoutObjCLifetime() == 1406 ArgQuals.withoutObjCLifetime())) { 1407 Info.FirstArg = TemplateArgument(ParamIn); 1408 Info.SecondArg = TemplateArgument(ArgIn); 1409 return Sema::TDK_NonDeducedMismatch; 1410 } 1411 } 1412 1413 // C++11 [temp.deduct.partial]p7: 1414 // Remove any top-level cv-qualifiers: 1415 // - If P is a cv-qualified type, P is replaced by the cv-unqualified 1416 // version of P. 1417 Param = Param.getUnqualifiedType(); 1418 // - If A is a cv-qualified type, A is replaced by the cv-unqualified 1419 // version of A. 1420 Arg = Arg.getUnqualifiedType(); 1421 } else { 1422 // C++0x [temp.deduct.call]p4 bullet 1: 1423 // - If the original P is a reference type, the deduced A (i.e., the type 1424 // referred to by the reference) can be more cv-qualified than the 1425 // transformed A. 1426 if (TDF & TDF_ParamWithReferenceType) {
4
←
Assuming the condition is false
→
5
←
Taking false branch
→
1427 Qualifiers Quals; 1428 QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals); 1429 Quals.setCVRQualifiers(Quals.getCVRQualifiers() & 1430 Arg.getCVRQualifiers()); 1431 Param = S.Context.getQualifiedType(UnqualParam, Quals); 1432 } 1433 1434 if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
6
←
Assuming the condition is false
→
1435 // C++0x [temp.deduct.type]p10: 1436 // If P and A are function types that originated from deduction when 1437 // taking the address of a function template (14.8.2.2) or when deducing 1438 // template arguments from a function declaration (14.8.2.6) and Pi and 1439 // Ai are parameters of the top-level parameter-type-list of P and A, 1440 // respectively, Pi is adjusted if it is a forwarding reference and Ai 1441 // is an lvalue reference, in 1442 // which case the type of Pi is changed to be the template parameter 1443 // type (i.e., T&& is changed to simply T). [ Note: As a result, when 1444 // Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be 1445 // deduced as X&. - end note ] 1446 TDF &= ~TDF_TopLevelParameterTypeList; 1447 if (isForwardingReference(Param, 0) && Arg->isLValueReferenceType()) 1448 Param = Param->getPointeeType(); 1449 } 1450 } 1451 1452 // C++ [temp.deduct.type]p9: 1453 // A template type argument T, a template template argument TT or a 1454 // template non-type argument i can be deduced if P and A have one of 1455 // the following forms: 1456 // 1457 // T 1458 // cv-list T 1459 if (const TemplateTypeParmType *TemplateTypeParm
7.1
'TemplateTypeParm' is null
8
←
Taking false branch
→
1460 = Param->getAs<TemplateTypeParmType>()) {
7
←
Assuming the object is not a 'TemplateTypeParmType'
→
1461 // Just skip any attempts to deduce from a placeholder type or a parameter 1462 // at a different depth. 1463 if (Arg->isPlaceholderType() || 1464 Info.getDeducedDepth() != TemplateTypeParm->getDepth()) 1465 return Sema::TDK_Success; 1466 1467 unsigned Index = TemplateTypeParm->getIndex(); 1468 bool RecanonicalizeArg = false; 1469 1470 // If the argument type is an array type, move the qualifiers up to the 1471 // top level, so they can be matched with the qualifiers on the parameter. 1472 if (isa<ArrayType>(Arg)) { 1473 Qualifiers Quals; 1474 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals); 1475 if (Quals) { 1476 Arg = S.Context.getQualifiedType(Arg, Quals); 1477 RecanonicalizeArg = true; 1478 } 1479 } 1480 1481 // The argument type can not be less qualified than the parameter 1482 // type. 1483 if (!(TDF & TDF_IgnoreQualifiers) && 1484 hasInconsistentOrSupersetQualifiersOf(Param, Arg)) { 1485 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 1486 Info.FirstArg = TemplateArgument(Param); 1487 Info.SecondArg = TemplateArgument(Arg); 1488 return Sema::TDK_Underqualified; 1489 } 1490 1491 // Do not match a function type with a cv-qualified type. 1492 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1584 1493 if (Arg->isFunctionType() && Param.hasQualifiers()) { 1494 return Sema::TDK_NonDeducedMismatch; 1495 } 1496 1497 assert(TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&((void)0) 1498 "saw template type parameter with wrong depth")((void)0); 1499 assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function")((void)0); 1500 QualType DeducedType = Arg; 1501 1502 // Remove any qualifiers on the parameter from the deduced type. 1503 // We checked the qualifiers for consistency above. 1504 Qualifiers DeducedQs = DeducedType.getQualifiers(); 1505 Qualifiers ParamQs = Param.getQualifiers(); 1506 DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers()); 1507 if (ParamQs.hasObjCGCAttr()) 1508 DeducedQs.removeObjCGCAttr(); 1509 if (ParamQs.hasAddressSpace()) 1510 DeducedQs.removeAddressSpace(); 1511 if (ParamQs.hasObjCLifetime()) 1512 DeducedQs.removeObjCLifetime(); 1513 1514 // Objective-C ARC: 1515 // If template deduction would produce a lifetime qualifier on a type 1516 // that is not a lifetime type, template argument deduction fails. 1517 if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() && 1518 !DeducedType->isDependentType()) { 1519 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 1520 Info.FirstArg = TemplateArgument(Param); 1521 Info.SecondArg = TemplateArgument(Arg); 1522 return Sema::TDK_Underqualified; 1523 } 1524 1525 // Objective-C ARC: 1526 // If template deduction would produce an argument type with lifetime type 1527 // but no lifetime qualifier, the __strong lifetime qualifier is inferred. 1528 if (S.getLangOpts().ObjCAutoRefCount && 1529 DeducedType->isObjCLifetimeType() && 1530 !DeducedQs.hasObjCLifetime()) 1531 DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong); 1532 1533 DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(), 1534 DeducedQs); 1535 1536 if (RecanonicalizeArg) 1537 DeducedType = S.Context.getCanonicalType(DeducedType); 1538 1539 DeducedTemplateArgument NewDeduced(DeducedType, DeducedFromArrayBound); 1540 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, 1541 Deduced[Index], 1542 NewDeduced); 1543 if (Result.isNull()) { 1544 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 1545 Info.FirstArg = Deduced[Index]; 1546 Info.SecondArg = NewDeduced; 1547 return Sema::TDK_Inconsistent; 1548 } 1549 1550 Deduced[Index] = Result; 1551 return Sema::TDK_Success; 1552 } 1553 1554 // Set up the template argument deduction information for a failure. 1555 Info.FirstArg = TemplateArgument(ParamIn); 1556 Info.SecondArg = TemplateArgument(ArgIn); 1557 1558 // If the parameter is an already-substituted template parameter 1559 // pack, do nothing: we don't know which of its arguments to look 1560 // at, so we have to wait until all of the parameter packs in this 1561 // expansion have arguments. 1562 if (isa<SubstTemplateTypeParmPackType>(Param))
9
←
Assuming 'Param' is not a 'SubstTemplateTypeParmPackType'
→
10
←
Taking false branch
→
1563 return Sema::TDK_Success; 1564 1565 // Check the cv-qualifiers on the parameter and argument types. 1566 CanQualType CanParam = S.Context.getCanonicalType(Param); 1567 CanQualType CanArg = S.Context.getCanonicalType(Arg); 1568 if (!(TDF & TDF_IgnoreQualifiers)) {
11
←
Assuming the condition is false
→
12
←
Taking false branch
→
1569 if (TDF & TDF_ParamWithReferenceType) { 1570 if (hasInconsistentOrSupersetQualifiersOf(Param, Arg)) 1571 return Sema::TDK_NonDeducedMismatch; 1572 } else if (TDF & TDF_ArgWithReferenceType) { 1573 // C++ [temp.deduct.conv]p4: 1574 // If the original A is a reference type, A can be more cv-qualified 1575 // than the deduced A 1576 if (!Arg.getQualifiers().compatiblyIncludes(Param.getQualifiers())) 1577 return Sema::TDK_NonDeducedMismatch; 1578 1579 // Strip out all extra qualifiers from the argument to figure out the 1580 // type we're converting to, prior to the qualification conversion. 1581 Qualifiers Quals; 1582 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals); 1583 Arg = S.Context.getQualifiedType(Arg, Param.getQualifiers()); 1584 } else if (!IsPossiblyOpaquelyQualifiedType(Param)) { 1585 if (Param.getCVRQualifiers() != Arg.getCVRQualifiers()) 1586 return Sema::TDK_NonDeducedMismatch; 1587 } 1588 1589 // If the parameter type is not dependent, there is nothing to deduce. 1590 if (!Param->isDependentType()) { 1591 if (!(TDF & TDF_SkipNonDependent)) { 1592 bool NonDeduced = 1593 (TDF & TDF_AllowCompatibleFunctionType) 1594 ? !S.isSameOrCompatibleFunctionType(CanParam, CanArg) 1595 : Param != Arg; 1596 if (NonDeduced) { 1597 return Sema::TDK_NonDeducedMismatch; 1598 } 1599 } 1600 return Sema::TDK_Success; 1601 } 1602 } else if (!Param->isDependentType()) {
13
←
Assuming the condition is false
→
14
←
Taking false branch
→
1603 if (!(TDF & TDF_SkipNonDependent)) { 1604 CanQualType ParamUnqualType = CanParam.getUnqualifiedType(), 1605 ArgUnqualType = CanArg.getUnqualifiedType(); 1606 bool Success = 1607 (TDF & TDF_AllowCompatibleFunctionType) 1608 ? S.isSameOrCompatibleFunctionType(ParamUnqualType, ArgUnqualType) 1609 : ParamUnqualType == ArgUnqualType; 1610 if (Success) 1611 return Sema::TDK_Success; 1612 } else { 1613 return Sema::TDK_Success; 1614 } 1615 } 1616 1617 switch (Param->getTypeClass()) {
15
←
Control jumps to 'case DependentSizedMatrix:' at line 2137
→
1618 // Non-canonical types cannot appear here. 1619#define NON_CANONICAL_TYPE(Class, Base) \ 1620 case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class)__builtin_unreachable(); 1621#define TYPE(Class, Base) 1622#include "clang/AST/TypeNodes.inc" 1623 1624 case Type::TemplateTypeParm: 1625 case Type::SubstTemplateTypeParmPack: 1626 llvm_unreachable("Type nodes handled above")__builtin_unreachable(); 1627 1628 // These types cannot be dependent, so simply check whether the types are 1629 // the same. 1630 case Type::Builtin: 1631 case Type::VariableArray: 1632 case Type::Vector: 1633 case Type::FunctionNoProto: 1634 case Type::Record: 1635 case Type::Enum: 1636 case Type::ObjCObject: 1637 case Type::ObjCInterface: 1638 case Type::ObjCObjectPointer: 1639 case Type::ExtInt: 1640 if (TDF & TDF_SkipNonDependent) 1641 return Sema::TDK_Success; 1642 1643 if (TDF & TDF_IgnoreQualifiers) { 1644 Param = Param.getUnqualifiedType(); 1645 Arg = Arg.getUnqualifiedType(); 1646 } 1647 1648 return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch; 1649 1650 // _Complex T [placeholder extension] 1651 case Type::Complex: 1652 if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>()) 1653 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1654 cast<ComplexType>(Param)->getElementType(), 1655 ComplexArg->getElementType(), 1656 Info, Deduced, TDF); 1657 1658 return Sema::TDK_NonDeducedMismatch; 1659 1660 // _Atomic T [extension] 1661 case Type::Atomic: 1662 if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>()) 1663 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1664 cast<AtomicType>(Param)->getValueType(), 1665 AtomicArg->getValueType(), 1666 Info, Deduced, TDF); 1667 1668 return Sema::TDK_NonDeducedMismatch; 1669 1670 // T * 1671 case Type::Pointer: { 1672 QualType PointeeType; 1673 if (const PointerType *PointerArg = Arg->getAs<PointerType>()) { 1674 PointeeType = PointerArg->getPointeeType(); 1675 } else if (const ObjCObjectPointerType *PointerArg 1676 = Arg->getAs<ObjCObjectPointerType>()) { 1677 PointeeType = PointerArg->getPointeeType(); 1678 } else { 1679 return Sema::TDK_NonDeducedMismatch; 1680 } 1681 1682 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass); 1683 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1684 cast<PointerType>(Param)->getPointeeType(), 1685 PointeeType, 1686 Info, Deduced, SubTDF); 1687 } 1688 1689 // T & 1690 case Type::LValueReference: { 1691 const LValueReferenceType *ReferenceArg = 1692 Arg->getAs<LValueReferenceType>(); 1693 if (!ReferenceArg) 1694 return Sema::TDK_NonDeducedMismatch; 1695 1696 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1697 cast<LValueReferenceType>(Param)->getPointeeType(), 1698 ReferenceArg->getPointeeType(), Info, Deduced, 0); 1699 } 1700 1701 // T && [C++0x] 1702 case Type::RValueReference: { 1703 const RValueReferenceType *ReferenceArg = 1704 Arg->getAs<RValueReferenceType>(); 1705 if (!ReferenceArg) 1706 return Sema::TDK_NonDeducedMismatch; 1707 1708 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1709 cast<RValueReferenceType>(Param)->getPointeeType(), 1710 ReferenceArg->getPointeeType(), 1711 Info, Deduced, 0); 1712 } 1713 1714 // T [] (implied, but not stated explicitly) 1715 case Type::IncompleteArray: { 1716 const IncompleteArrayType *IncompleteArrayArg = 1717 S.Context.getAsIncompleteArrayType(Arg); 1718 if (!IncompleteArrayArg) 1719 return Sema::TDK_NonDeducedMismatch; 1720 1721 unsigned SubTDF = TDF & TDF_IgnoreQualifiers; 1722 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1723 S.Context.getAsIncompleteArrayType(Param)->getElementType(), 1724 IncompleteArrayArg->getElementType(), 1725 Info, Deduced, SubTDF); 1726 } 1727 1728 // T [integer-constant] 1729 case Type::ConstantArray: { 1730 const ConstantArrayType *ConstantArrayArg = 1731 S.Context.getAsConstantArrayType(Arg); 1732 if (!ConstantArrayArg) 1733 return Sema::TDK_NonDeducedMismatch; 1734 1735 const ConstantArrayType *ConstantArrayParm = 1736 S.Context.getAsConstantArrayType(Param); 1737 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize()) 1738 return Sema::TDK_NonDeducedMismatch; 1739 1740 unsigned SubTDF = TDF & TDF_IgnoreQualifiers; 1741 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1742 ConstantArrayParm->getElementType(), 1743 ConstantArrayArg->getElementType(), 1744 Info, Deduced, SubTDF); 1745 } 1746 1747 // type [i] 1748 case Type::DependentSizedArray: { 1749 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg); 1750 if (!ArrayArg) 1751 return Sema::TDK_NonDeducedMismatch; 1752 1753 unsigned SubTDF = TDF & TDF_IgnoreQualifiers; 1754 1755 // Check the element type of the arrays 1756 const DependentSizedArrayType *DependentArrayParm 1757 = S.Context.getAsDependentSizedArrayType(Param); 1758 if (Sema::TemplateDeductionResult Result 1759 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1760 DependentArrayParm->getElementType(), 1761 ArrayArg->getElementType(), 1762 Info, Deduced, SubTDF)) 1763 return Result; 1764 1765 // Determine the array bound is something we can deduce. 1766 const NonTypeTemplateParmDecl *NTTP 1767 = getDeducedParameterFromExpr(Info, DependentArrayParm->getSizeExpr()); 1768 if (!NTTP) 1769 return Sema::TDK_Success; 1770 1771 // We can perform template argument deduction for the given non-type 1772 // template parameter. 1773 assert(NTTP->getDepth() == Info.getDeducedDepth() &&((void)0) 1774 "saw non-type template parameter with wrong depth")((void)0); 1775 if (const ConstantArrayType *ConstantArrayArg 1776 = dyn_cast<ConstantArrayType>(ArrayArg)) { 1777 llvm::APSInt Size(ConstantArrayArg->getSize()); 1778 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, Size, 1779 S.Context.getSizeType(), 1780 /*ArrayBound=*/true, 1781 Info, Deduced); 1782 } 1783 if (const DependentSizedArrayType *DependentArrayArg 1784 = dyn_cast<DependentSizedArrayType>(ArrayArg)) 1785 if (DependentArrayArg->getSizeExpr()) 1786 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, 1787 DependentArrayArg->getSizeExpr(), 1788 Info, Deduced); 1789 1790 // Incomplete type does not match a dependently-sized array type 1791 return Sema::TDK_NonDeducedMismatch; 1792 } 1793 1794 // type(*)(T) 1795 // T(*)() 1796 // T(*)(T) 1797 case Type::FunctionProto: { 1798 unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList; 1799 const FunctionProtoType *FunctionProtoArg = 1800 dyn_cast<FunctionProtoType>(Arg); 1801 if (!FunctionProtoArg) 1802 return Sema::TDK_NonDeducedMismatch; 1803 1804 const FunctionProtoType *FunctionProtoParam = 1805 cast<FunctionProtoType>(Param); 1806 1807 if (FunctionProtoParam->getMethodQuals() 1808 != FunctionProtoArg->getMethodQuals() || 1809 FunctionProtoParam->getRefQualifier() 1810 != FunctionProtoArg->getRefQualifier() || 1811 FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic()) 1812 return Sema::TDK_NonDeducedMismatch; 1813 1814 // Check return types. 1815 if (auto Result = DeduceTemplateArgumentsByTypeMatch( 1816 S, TemplateParams, FunctionProtoParam->getReturnType(), 1817 FunctionProtoArg->getReturnType(), Info, Deduced, 0)) 1818 return Result; 1819 1820 // Check parameter types. 1821 if (auto Result = DeduceTemplateArguments( 1822 S, TemplateParams, FunctionProtoParam->param_type_begin(), 1823 FunctionProtoParam->getNumParams(), 1824 FunctionProtoArg->param_type_begin(), 1825 FunctionProtoArg->getNumParams(), Info, Deduced, SubTDF)) 1826 return Result; 1827 1828 if (TDF & TDF_AllowCompatibleFunctionType) 1829 return Sema::TDK_Success; 1830 1831 // FIXME: Per core-2016/10/1019 (no corresponding core issue yet), permit 1832 // deducing through the noexcept-specifier if it's part of the canonical 1833 // type. libstdc++ relies on this. 1834 Expr *NoexceptExpr = FunctionProtoParam->getNoexceptExpr(); 1835 if (const NonTypeTemplateParmDecl *NTTP = 1836 NoexceptExpr ? getDeducedParameterFromExpr(Info, NoexceptExpr) 1837 : nullptr) { 1838 assert(NTTP->getDepth() == Info.getDeducedDepth() &&((void)0) 1839 "saw non-type template parameter with wrong depth")((void)0); 1840 1841 llvm::APSInt Noexcept(1); 1842 switch (FunctionProtoArg->canThrow()) { 1843 case CT_Cannot: 1844 Noexcept = 1; 1845 LLVM_FALLTHROUGH[[gnu::fallthrough]]; 1846 1847 case CT_Can: 1848 // We give E in noexcept(E) the "deduced from array bound" treatment. 1849 // FIXME: Should we? 1850 return DeduceNonTypeTemplateArgument( 1851 S, TemplateParams, NTTP, Noexcept, S.Context.BoolTy, 1852 /*ArrayBound*/true, Info, Deduced); 1853 1854 case CT_Dependent: 1855 if (Expr *ArgNoexceptExpr = FunctionProtoArg->getNoexceptExpr()) 1856 return DeduceNonTypeTemplateArgument( 1857 S, TemplateParams, NTTP, ArgNoexceptExpr, Info, Deduced); 1858 // Can't deduce anything from throw(T...). 1859 break; 1860 } 1861 } 1862 // FIXME: Detect non-deduced exception specification mismatches? 1863 // 1864 // Careful about [temp.deduct.call] and [temp.deduct.conv], which allow 1865 // top-level differences in noexcept-specifications. 1866 1867 return Sema::TDK_Success; 1868 } 1869 1870 case Type::InjectedClassName: 1871 // Treat a template's injected-class-name as if the template 1872 // specialization type had been used. 1873 Param = cast<InjectedClassNameType>(Param) 1874 ->getInjectedSpecializationType(); 1875 assert(isa<TemplateSpecializationType>(Param) &&((void)0) 1876 "injected class name is not a template specialization type")((void)0); 1877 LLVM_FALLTHROUGH[[gnu::fallthrough]]; 1878 1879 // template-name<T> (where template-name refers to a class template) 1880 // template-name<i> 1881 // TT<T> 1882 // TT<i> 1883 // TT<> 1884 case Type::TemplateSpecialization: { 1885 const TemplateSpecializationType *SpecParam = 1886 cast<TemplateSpecializationType>(Param); 1887 1888 // When Arg cannot be a derived class, we can just try to deduce template 1889 // arguments from the template-id. 1890 const RecordType *RecordT = Arg->getAs<RecordType>(); 1891 if (!(TDF & TDF_DerivedClass) || !RecordT) 1892 return DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, Info, 1893 Deduced); 1894 1895 SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(), 1896 Deduced.end()); 1897 1898 Sema::TemplateDeductionResult Result = DeduceTemplateArguments( 1899 S, TemplateParams, SpecParam, Arg, Info, Deduced); 1900 1901 if (Result == Sema::TDK_Success) 1902 return Result; 1903 1904 // We cannot inspect base classes as part of deduction when the type 1905 // is incomplete, so either instantiate any templates necessary to 1906 // complete the type, or skip over it if it cannot be completed. 1907 if (!S.isCompleteType(Info.getLocation(), Arg)) 1908 return Result; 1909 1910 // Reset the incorrectly deduced argument from above. 1911 Deduced = DeducedOrig; 1912 1913 // Check bases according to C++14 [temp.deduct.call] p4b3: 1914 Sema::TemplateDeductionResult BaseResult = DeduceTemplateBases( 1915 S, RecordT, TemplateParams, SpecParam, Info, Deduced); 1916 1917 if (BaseResult != Sema::TDK_Invalid) 1918 return BaseResult; 1919 return Result; 1920 } 1921 1922 // T type::* 1923 // T T::* 1924 // T (type::*)() 1925 // type (T::*)() 1926 // type (type::*)(T) 1927 // type (T::*)(T) 1928 // T (type::*)(T) 1929 // T (T::*)() 1930 // T (T::*)(T) 1931 case Type::MemberPointer: { 1932 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param); 1933 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg); 1934 if (!MemPtrArg) 1935 return Sema::TDK_NonDeducedMismatch; 1936 1937 QualType ParamPointeeType = MemPtrParam->getPointeeType(); 1938 if (ParamPointeeType->isFunctionType()) 1939 S.adjustMemberFunctionCC(ParamPointeeType, /*IsStatic=*/true, 1940 /*IsCtorOrDtor=*/false, Info.getLocation()); 1941 QualType ArgPointeeType = MemPtrArg->getPointeeType(); 1942 if (ArgPointeeType->isFunctionType()) 1943 S.adjustMemberFunctionCC(ArgPointeeType, /*IsStatic=*/true, 1944 /*IsCtorOrDtor=*/false, Info.getLocation()); 1945 1946 if (Sema::TemplateDeductionResult Result 1947 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1948 ParamPointeeType, 1949 ArgPointeeType, 1950 Info, Deduced, 1951 TDF & TDF_IgnoreQualifiers)) 1952 return Result; 1953 1954 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1955 QualType(MemPtrParam->getClass(), 0), 1956 QualType(MemPtrArg->getClass(), 0), 1957 Info, Deduced, 1958 TDF & TDF_IgnoreQualifiers); 1959 } 1960 1961 // (clang extension) 1962 // 1963 // type(^)(T) 1964 // T(^)() 1965 // T(^)(T) 1966 case Type::BlockPointer: { 1967 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param); 1968 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg); 1969 1970 if (!BlockPtrArg) 1971 return Sema::TDK_NonDeducedMismatch; 1972 1973 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1974 BlockPtrParam->getPointeeType(), 1975 BlockPtrArg->getPointeeType(), 1976 Info, Deduced, 0); 1977 } 1978 1979 // (clang extension) 1980 // 1981 // T __attribute__(((ext_vector_type(<integral constant>)))) 1982 case Type::ExtVector: { 1983 const ExtVectorType *VectorParam = cast<ExtVectorType>(Param); 1984 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) { 1985 // Make sure that the vectors have the same number of elements. 1986 if (VectorParam->getNumElements() != VectorArg->getNumElements()) 1987 return Sema::TDK_NonDeducedMismatch; 1988 1989 // Perform deduction on the element types. 1990 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1991 VectorParam->getElementType(), 1992 VectorArg->getElementType(), 1993 Info, Deduced, TDF); 1994 } 1995 1996 if (const DependentSizedExtVectorType *VectorArg 1997 = dyn_cast<DependentSizedExtVectorType>(Arg)) { 1998 // We can't check the number of elements, since the argument has a 1999 // dependent number of elements. This can only occur during partial 2000 // ordering. 2001 2002 // Perform deduction on the element types. 2003 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 2004 VectorParam->getElementType(), 2005 VectorArg->getElementType(), 2006 Info, Deduced, TDF); 2007 } 2008 2009 return Sema::TDK_NonDeducedMismatch; 2010 } 2011 2012 case Type::DependentVector: { 2013 const auto *VectorParam = cast<DependentVectorType>(Param); 2014 2015 if (const auto *VectorArg = dyn_cast<VectorType>(Arg)) { 2016 // Perform deduction on the element types. 2017 if (Sema::TemplateDeductionResult Result = 2018 DeduceTemplateArgumentsByTypeMatch( 2019 S, TemplateParams, VectorParam->getElementType(), 2020 VectorArg->getElementType(), Info, Deduced, TDF)) 2021 return Result; 2022 2023 // Perform deduction on the vector size, if we can. 2024 const NonTypeTemplateParmDecl *NTTP = 2025 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr()); 2026 if (!NTTP) 2027 return Sema::TDK_Success; 2028 2029 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false); 2030 ArgSize = VectorArg->getNumElements(); 2031 // Note that we use the "array bound" rules here; just like in that 2032 // case, we don't have any particular type for the vector size, but 2033 // we can provide one if necessary. 2034 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize, 2035 S.Context.UnsignedIntTy, true, 2036 Info, Deduced); 2037 } 2038 2039 if (const auto *VectorArg = dyn_cast<DependentVectorType>(Arg)) { 2040 // Perform deduction on the element types. 2041 if (Sema::TemplateDeductionResult Result = 2042 DeduceTemplateArgumentsByTypeMatch( 2043 S, TemplateParams, VectorParam->getElementType(), 2044 VectorArg->getElementType(), Info, Deduced, TDF)) 2045 return Result; 2046 2047 // Perform deduction on the vector size, if we can. 2048 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr( 2049 Info, VectorParam->getSizeExpr()); 2050 if (!NTTP) 2051 return Sema::TDK_Success; 2052 2053 return DeduceNonTypeTemplateArgument( 2054 S, TemplateParams, NTTP, VectorArg->getSizeExpr(), Info, Deduced); 2055 } 2056 2057 return Sema::TDK_NonDeducedMismatch; 2058 } 2059 2060 // (clang extension) 2061 // 2062 // T __attribute__(((ext_vector_type(N)))) 2063 case Type::DependentSizedExtVector: { 2064 const DependentSizedExtVectorType *VectorParam 2065 = cast<DependentSizedExtVectorType>(Param); 2066 2067 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) { 2068 // Perform deduction on the element types. 2069 if (Sema::TemplateDeductionResult Result 2070 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 2071 VectorParam->getElementType(), 2072 VectorArg->getElementType(), 2073 Info, Deduced, TDF)) 2074 return Result; 2075 2076 // Perform deduction on the vector size, if we can. 2077 const NonTypeTemplateParmDecl *NTTP = 2078 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr()); 2079 if (!NTTP) 2080 return Sema::TDK_Success; 2081 2082 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false); 2083 ArgSize = VectorArg->getNumElements(); 2084 // Note that we use the "array bound" rules here; just like in that 2085 // case, we don't have any particular type for the vector size, but 2086 // we can provide one if necessary. 2087 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize, 2088 S.Context.IntTy, true, Info, 2089 Deduced); 2090 } 2091 2092 if (const DependentSizedExtVectorType *VectorArg 2093 = dyn_cast<DependentSizedExtVectorType>(Arg)) { 2094 // Perform deduction on the element types. 2095 if (Sema::TemplateDeductionResult Result 2096 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 2097 VectorParam->getElementType(), 2098 VectorArg->getElementType(), 2099 Info, Deduced, TDF)) 2100 return Result; 2101 2102 // Perform deduction on the vector size, if we can. 2103 const NonTypeTemplateParmDecl *NTTP = 2104 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr()); 2105 if (!NTTP) 2106 return Sema::TDK_Success; 2107 2108 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, 2109 VectorArg->getSizeExpr(), 2110 Info, Deduced); 2111 } 2112 2113 return Sema::TDK_NonDeducedMismatch; 2114 } 2115 2116 // (clang extension) 2117 // 2118 // T __attribute__((matrix_type(<integral constant>, 2119 // <integral constant>))) 2120 case Type::ConstantMatrix: { 2121 const ConstantMatrixType *MatrixArg = dyn_cast<ConstantMatrixType>(Arg); 2122 if (!MatrixArg) 2123 return Sema::TDK_NonDeducedMismatch; 2124 2125 const ConstantMatrixType *MatrixParam = cast<ConstantMatrixType>(Param); 2126 // Check that the dimensions are the same 2127 if (MatrixParam->getNumRows() != MatrixArg->getNumRows() || 2128 MatrixParam->getNumColumns() != MatrixArg->getNumColumns()) { 2129 return Sema::TDK_NonDeducedMismatch; 2130 } 2131 // Perform deduction on element types. 2132 return DeduceTemplateArgumentsByTypeMatch( 2133 S, TemplateParams, MatrixParam->getElementType(), 2134 MatrixArg->getElementType(), Info, Deduced, TDF); 2135 } 2136 2137 case Type::DependentSizedMatrix: { 2138 const MatrixType *MatrixArg = dyn_cast<MatrixType>(Arg); 2139 if (!MatrixArg)
16
←
Assuming 'MatrixArg' is non-null
→
17
←
Taking false branch
→
2140 return Sema::TDK_NonDeducedMismatch; 2141 2142 // Check the element type of the matrixes. 2143 const DependentSizedMatrixType *MatrixParam = 2144 cast<DependentSizedMatrixType>(Param); 2145 if (Sema::TemplateDeductionResult Result =
18
←
Assuming 'Result' is 0
→
19
←
Taking false branch
→
2146 DeduceTemplateArgumentsByTypeMatch( 2147 S, TemplateParams, MatrixParam->getElementType(), 2148 MatrixArg->getElementType(), Info, Deduced, TDF)) 2149 return Result; 2150 2151 // Try to deduce a matrix dimension. 2152 auto DeduceMatrixArg = 2153 [&S, &Info, &Deduced, &TemplateParams]( 2154 Expr *ParamExpr, const MatrixType *Arg, 2155 unsigned (ConstantMatrixType::*GetArgDimension)() const, 2156 Expr *(DependentSizedMatrixType::*GetArgDimensionExpr)() const) { 2157 const auto *ArgConstMatrix = dyn_cast<ConstantMatrixType>(Arg);
21
←
Assuming 'Arg' is not a 'ConstantMatrixType'
→
2158 const auto *ArgDepMatrix = dyn_cast<DependentSizedMatrixType>(Arg);
22
←
Assuming 'Arg' is not a 'DependentSizedMatrixType'
→
23
←
'ArgDepMatrix' initialized to a null pointer value
→
2159 if (!ParamExpr->isValueDependent()) {
24
←
Assuming the condition is true
→
25
←
Taking true branch
→
2160 Optional<llvm::APSInt> ParamConst = 2161 ParamExpr->getIntegerConstantExpr(S.Context); 2162 if (!ParamConst)
26
←
Assuming the condition is false
→
27
←
Taking false branch
→
2163 return Sema::TDK_NonDeducedMismatch; 2164 2165 if (ArgConstMatrix
27.1
'ArgConstMatrix' is null
) {
28
←
Taking false branch
→
2166 if ((ArgConstMatrix->*GetArgDimension)() == *ParamConst) 2167 return Sema::TDK_Success; 2168 return Sema::TDK_NonDeducedMismatch; 2169 } 2170 2171 Expr *ArgExpr = (ArgDepMatrix->*GetArgDimensionExpr)();
29
←
Called C++ object pointer is null
2172 if (!ArgExpr->isValueDependent()) 2173 if (Optional<llvm::APSInt> ArgConst = 2174 ArgExpr->getIntegerConstantExpr(S.Context)) 2175 if (*ArgConst == *ParamConst) 2176 return Sema::TDK_Success; 2177 return Sema::TDK_NonDeducedMismatch; 2178 } 2179 2180 const NonTypeTemplateParmDecl *NTTP = 2181 getDeducedParameterFromExpr(Info, ParamExpr); 2182 if (!NTTP) 2183 return Sema::TDK_Success; 2184 2185 if (ArgConstMatrix) { 2186 llvm::APSInt ArgConst( 2187 S.Context.getTypeSize(S.Context.getSizeType())); 2188 ArgConst = (ArgConstMatrix->*GetArgDimension)(); 2189 return DeduceNonTypeTemplateArgument( 2190 S, TemplateParams, NTTP, ArgConst, S.Context.getSizeType(), 2191 /*ArrayBound=*/true, Info, Deduced); 2192 } 2193 2194 return DeduceNonTypeTemplateArgument( 2195 S, TemplateParams, NTTP, (ArgDepMatrix->*GetArgDimensionExpr)(), 2196 Info, Deduced); 2197 }; 2198 2199 auto Result = DeduceMatrixArg(MatrixParam->getRowExpr(), MatrixArg,
20
←
Calling 'operator()'
→
2200 &ConstantMatrixType::getNumRows, 2201 &DependentSizedMatrixType::getRowExpr); 2202 if (Result) 2203 return Result; 2204 2205 return DeduceMatrixArg(MatrixParam->getColumnExpr(), MatrixArg, 2206 &ConstantMatrixType::getNumColumns, 2207 &DependentSizedMatrixType::getColumnExpr); 2208 } 2209 2210 // (clang extension) 2211 // 2212 // T __attribute__(((address_space(N)))) 2213 case Type::DependentAddressSpace: { 2214 const DependentAddressSpaceType *AddressSpaceParam = 2215 cast<DependentAddressSpaceType>(Param); 2216 2217 if (const DependentAddressSpaceType *AddressSpaceArg = 2218 dyn_cast<DependentAddressSpaceType>(Arg)) { 2219 // Perform deduction on the pointer type. 2220 if (Sema::TemplateDeductionResult Result = 2221 DeduceTemplateArgumentsByTypeMatch( 2222 S, TemplateParams, AddressSpaceParam->getPointeeType(), 2223 AddressSpaceArg->getPointeeType(), Info, Deduced, TDF)) 2224 return Result; 2225 2226 // Perform deduction on the address space, if we can. 2227 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr( 2228 Info, AddressSpaceParam->getAddrSpaceExpr()); 2229 if (!NTTP) 2230 return Sema::TDK_Success; 2231 2232 return DeduceNonTypeTemplateArgument( 2233 S, TemplateParams, NTTP, AddressSpaceArg->getAddrSpaceExpr(), Info, 2234 Deduced); 2235 } 2236 2237 if (isTargetAddressSpace(Arg.getAddressSpace())) { 2238 llvm::APSInt ArgAddressSpace(S.Context.getTypeSize(S.Context.IntTy), 2239 false); 2240 ArgAddressSpace = toTargetAddressSpace(Arg.getAddressSpace()); 2241 2242 // Perform deduction on the pointer types. 2243 if (Sema::TemplateDeductionResult Result = 2244 DeduceTemplateArgumentsByTypeMatch( 2245 S, TemplateParams, AddressSpaceParam->getPointeeType(), 2246 S.Context.removeAddrSpaceQualType(Arg), Info, Deduced, TDF)) 2247 return Result; 2248 2249 // Perform deduction on the address space, if we can. 2250 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr( 2251 Info, AddressSpaceParam->getAddrSpaceExpr()); 2252 if (!NTTP) 2253 return Sema::TDK_Success; 2254 2255 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, 2256 ArgAddressSpace, S.Context.IntTy, 2257 true, Info, Deduced); 2258 } 2259 2260 return Sema::TDK_NonDeducedMismatch; 2261 } 2262 case Type::DependentExtInt: { 2263 const auto *IntParam = cast<DependentExtIntType>(Param); 2264 2265 if (const auto *IntArg = dyn_cast<ExtIntType>(Arg)){ 2266 if (IntParam->isUnsigned() != IntArg->isUnsigned()) 2267 return Sema::TDK_NonDeducedMismatch; 2268 2269 const NonTypeTemplateParmDecl *NTTP = 2270 getDeducedParameterFromExpr(Info, IntParam->getNumBitsExpr()); 2271 if (!NTTP) 2272 return Sema::TDK_Success; 2273 2274 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false); 2275 ArgSize = IntArg->getNumBits(); 2276 2277 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize, 2278 S.Context.IntTy, true, Info, 2279 Deduced); 2280 } 2281 2282 if (const auto *IntArg = dyn_cast<DependentExtIntType>(Arg)) { 2283 if (IntParam->isUnsigned() != IntArg->isUnsigned()) 2284 return Sema::TDK_NonDeducedMismatch; 2285 return Sema::TDK_Success; 2286 } 2287 return Sema::TDK_NonDeducedMismatch; 2288 } 2289 2290 case Type::TypeOfExpr: 2291 case Type::TypeOf: 2292 case Type::DependentName: 2293 case Type::UnresolvedUsing: 2294 case Type::Decltype: 2295 case Type::UnaryTransform: 2296 case Type::Auto: 2297 case Type::DeducedTemplateSpecialization: 2298 case Type::DependentTemplateSpecialization: 2299 case Type::PackExpansion: 2300 case Type::Pipe: 2301 // No template argument deduction for these types 2302 return Sema::TDK_Success; 2303 } 2304 2305 llvm_unreachable("Invalid Type Class!")__builtin_unreachable(); 2306} 2307 2308static Sema::TemplateDeductionResult 2309DeduceTemplateArguments(Sema &S, 2310 TemplateParameterList *TemplateParams, 2311 const TemplateArgument &Param, 2312 TemplateArgument Arg, 2313 TemplateDeductionInfo &Info, 2314 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 2315 // If the template argument is a pack expansion, perform template argument 2316 // deduction against the pattern of that expansion. This only occurs during 2317 // partial ordering. 2318 if (Arg.isPackExpansion()) 2319 Arg = Arg.getPackExpansionPattern(); 2320 2321 switch (Param.getKind()) { 2322 case TemplateArgument::Null: 2323 llvm_unreachable("Null template argument in parameter list")__builtin_unreachable(); 2324 2325 case TemplateArgument::Type: 2326 if (Arg.getKind() == TemplateArgument::Type) 2327 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 2328 Param.getAsType(), 2329 Arg.getAsType(), 2330 Info, Deduced, 0); 2331 Info.FirstArg = Param; 2332 Info.SecondArg = Arg; 2333 return Sema::TDK_NonDeducedMismatch; 2334 2335 case TemplateArgument::Template: 2336 if (Arg.getKind() == TemplateArgument::Template) 2337 return DeduceTemplateArguments(S, TemplateParams, 2338 Param.getAsTemplate(), 2339 Arg.getAsTemplate(), Info, Deduced); 2340 Info.FirstArg = Param; 2341 Info.SecondArg = Arg; 2342 return Sema::TDK_NonDeducedMismatch; 2343 2344 case TemplateArgument::TemplateExpansion: 2345 llvm_unreachable("caller should handle pack expansions")__builtin_unreachable(); 2346 2347 case TemplateArgument::Declaration: 2348 if (Arg.getKind() == TemplateArgument::Declaration && 2349 isSameDeclaration(Param.getAsDecl(), Arg.getAsDecl())) 2350 return Sema::TDK_Success; 2351 2352 Info.FirstArg = Param; 2353 Info.SecondArg = Arg; 2354 return Sema::TDK_NonDeducedMismatch; 2355 2356 case TemplateArgument::NullPtr: 2357 if (Arg.getKind() == TemplateArgument::NullPtr && 2358 S.Context.hasSameType(Param.getNullPtrType(), Arg.getNullPtrType())) 2359 return Sema::TDK_Success; 2360 2361 Info.FirstArg = Param; 2362 Info.SecondArg = Arg; 2363 return Sema::TDK_NonDeducedMismatch; 2364 2365 case TemplateArgument::Integral: 2366 if (Arg.getKind() == TemplateArgument::Integral) { 2367 if (hasSameExtendedValue(Param.getAsIntegral(), Arg.getAsIntegral())) 2368 return Sema::TDK_Success; 2369 2370 Info.FirstArg = Param; 2371 Info.SecondArg = Arg; 2372 return Sema::TDK_NonDeducedMismatch; 2373 } 2374 2375 if (Arg.getKind() == TemplateArgument::Expression) { 2376 Info.FirstArg = Param; 2377 Info.SecondArg = Arg; 2378 return Sema::TDK_NonDeducedMismatch; 2379 } 2380 2381 Info.FirstArg = Param; 2382 Info.SecondArg = Arg; 2383 return Sema::TDK_NonDeducedMismatch; 2384 2385 case TemplateArgument::Expression: 2386 if (const NonTypeTemplateParmDecl *NTTP = 2387 getDeducedParameterFromExpr(Info, Param.getAsExpr())) { 2388 if (Arg.getKind() == TemplateArgument::Integral) 2389 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, 2390 Arg.getAsIntegral(), 2391 Arg.getIntegralType(), 2392 /*ArrayBound=*/false, 2393 Info, Deduced); 2394 if (Arg.getKind() == TemplateArgument::NullPtr) 2395 return DeduceNullPtrTemplateArgument(S, TemplateParams, NTTP, 2396 Arg.getNullPtrType(), 2397 Info, Deduced); 2398 if (Arg.getKind() == TemplateArgument::Expression) 2399 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, 2400 Arg.getAsExpr(), Info, Deduced); 2401 if (Arg.getKind() == TemplateArgument::Declaration) 2402 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, 2403 Arg.getAsDecl(), 2404 Arg.getParamTypeForDecl(), 2405 Info, Deduced); 2406 2407 Info.FirstArg = Param; 2408 Info.SecondArg = Arg; 2409 return Sema::TDK_NonDeducedMismatch; 2410 } 2411 2412 // Can't deduce anything, but that's okay. 2413 return Sema::TDK_Success; 2414 2415 case TemplateArgument::Pack: 2416 llvm_unreachable("Argument packs should be expanded by the caller!")__builtin_unreachable(); 2417 } 2418 2419 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable(); 2420} 2421 2422/// Determine whether there is a template argument to be used for 2423/// deduction. 2424/// 2425/// This routine "expands" argument packs in-place, overriding its input 2426/// parameters so that \c Args[ArgIdx] will be the available template argument. 2427/// 2428/// \returns true if there is another template argument (which will be at 2429/// \c Args[ArgIdx]), false otherwise. 2430static bool hasTemplateArgumentForDeduction(ArrayRef<TemplateArgument> &Args, 2431 unsigned &ArgIdx) { 2432 if (ArgIdx == Args.size()) 2433 return false; 2434 2435 const TemplateArgument &Arg = Args[ArgIdx]; 2436 if (Arg.getKind() != TemplateArgument::Pack) 2437 return true; 2438 2439 assert(ArgIdx == Args.size() - 1 && "Pack not at the end of argument list?")((void)0); 2440 Args = Arg.pack_elements(); 2441 ArgIdx = 0; 2442 return ArgIdx < Args.size(); 2443} 2444 2445/// Determine whether the given set of template arguments has a pack 2446/// expansion that is not the last template argument. 2447static bool hasPackExpansionBeforeEnd(ArrayRef<TemplateArgument> Args) { 2448 bool FoundPackExpansion = false; 2449 for (const auto &A : Args) { 2450 if (FoundPackExpansion) 2451 return true; 2452 2453 if (A.getKind() == TemplateArgument::Pack) 2454 return hasPackExpansionBeforeEnd(A.pack_elements()); 2455 2456 // FIXME: If this is a fixed-arity pack expansion from an outer level of 2457 // templates, it should not be treated as a pack expansion. 2458 if (A.isPackExpansion()) 2459 FoundPackExpansion = true; 2460 } 2461 2462 return false; 2463} 2464 2465static Sema::TemplateDeductionResult 2466DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams, 2467 ArrayRef<TemplateArgument> Params, 2468 ArrayRef<TemplateArgument> Args, 2469 TemplateDeductionInfo &Info, 2470 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2471 bool NumberOfArgumentsMustMatch) { 2472 // C++0x [temp.deduct.type]p9: 2473 // If the template argument list of P contains a pack expansion that is not 2474 // the last template argument, the entire template argument list is a 2475 // non-deduced context. 2476 if (hasPackExpansionBeforeEnd(Params)) 2477 return Sema::TDK_Success; 2478 2479 // C++0x [temp.deduct.type]p9: 2480 // If P has a form that contains <T> or <i>, then each argument Pi of the 2481 // respective template argument list P is compared with the corresponding 2482 // argument Ai of the corresponding template argument list of A. 2483 unsigned ArgIdx = 0, ParamIdx = 0; 2484 for (; hasTemplateArgumentForDeduction(Params, ParamIdx); ++ParamIdx) { 2485 if (!Params[ParamIdx].isPackExpansion()) { 2486 // The simple case: deduce template arguments by matching Pi and Ai. 2487 2488 // Check whether we have enough arguments. 2489 if (!hasTemplateArgumentForDeduction(Args, ArgIdx)) 2490 return NumberOfArgumentsMustMatch 2491 ? Sema::TDK_MiscellaneousDeductionFailure 2492 : Sema::TDK_Success; 2493 2494 // C++1z [temp.deduct.type]p9: 2495 // During partial ordering, if Ai was originally a pack expansion [and] 2496 // Pi is not a pack expansion, template argument deduction fails. 2497 if (Args[ArgIdx].isPackExpansion()) 2498 return Sema::TDK_MiscellaneousDeductionFailure; 2499 2500 // Perform deduction for this Pi/Ai pair. 2501 if (Sema::TemplateDeductionResult Result 2502 = DeduceTemplateArguments(S, TemplateParams, 2503 Params[ParamIdx], Args[ArgIdx], 2504 Info, Deduced)) 2505 return Result; 2506 2507 // Move to the next argument. 2508 ++ArgIdx; 2509 continue; 2510 } 2511 2512 // The parameter is a pack expansion. 2513 2514 // C++0x [temp.deduct.type]p9: 2515 // If Pi is a pack expansion, then the pattern of Pi is compared with 2516 // each remaining argument in the template argument list of A. Each 2517 // comparison deduces template arguments for subsequent positions in the 2518 // template parameter packs expanded by Pi. 2519 TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern(); 2520 2521 // Prepare to deduce the packs within the pattern. 2522 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern); 2523 2524 // Keep track of the deduced template arguments for each parameter pack 2525 // expanded by this pack expansion (the outer index) and for each 2526 // template argument (the inner SmallVectors). 2527 for (; hasTemplateArgumentForDeduction(Args, ArgIdx) && 2528 PackScope.hasNextElement(); 2529 ++ArgIdx) { 2530 // Deduce template arguments from the pattern. 2531 if (Sema::TemplateDeductionResult Result 2532 = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx], 2533 Info, Deduced)) 2534 return Result; 2535 2536 PackScope.nextPackElement(); 2537 } 2538 2539 // Build argument packs for each of the parameter packs expanded by this 2540 // pack expansion. 2541 if (auto Result = PackScope.finish()) 2542 return Result; 2543 } 2544 2545 return Sema::TDK_Success; 2546} 2547 2548static Sema::TemplateDeductionResult 2549DeduceTemplateArguments(Sema &S, 2550 TemplateParameterList *TemplateParams, 2551 const TemplateArgumentList &ParamList, 2552 const TemplateArgumentList &ArgList, 2553 TemplateDeductionInfo &Info, 2554 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 2555 return DeduceTemplateArguments(S, TemplateParams, ParamList.asArray(), 2556 ArgList.asArray(), Info, Deduced, 2557 /*NumberOfArgumentsMustMatch*/false); 2558} 2559 2560/// Determine whether two template arguments are the same. 2561static bool isSameTemplateArg(ASTContext &Context, 2562 TemplateArgument X, 2563 const TemplateArgument &Y, 2564 bool PackExpansionMatchesPack = false) { 2565 // If we're checking deduced arguments (X) against original arguments (Y), 2566 // we will have flattened packs to non-expansions in X. 2567 if (PackExpansionMatchesPack && X.isPackExpansion() && !Y.isPackExpansion()) 2568 X = X.getPackExpansionPattern(); 2569 2570 if (X.getKind() != Y.getKind()) 2571 return false; 2572 2573 switch (X.getKind()) { 2574 case TemplateArgument::Null: 2575 llvm_unreachable("Comparing NULL template argument")__builtin_unreachable(); 2576 2577 case TemplateArgument::Type: 2578 return Context.getCanonicalType(X.getAsType()) == 2579 Context.getCanonicalType(Y.getAsType()); 2580 2581 case TemplateArgument::Declaration: 2582 return isSameDeclaration(X.getAsDecl(), Y.getAsDecl()); 2583 2584 case TemplateArgument::NullPtr: 2585 return Context.hasSameType(X.getNullPtrType(), Y.getNullPtrType()); 2586 2587 case TemplateArgument::Template: 2588 case TemplateArgument::TemplateExpansion: 2589 return Context.getCanonicalTemplateName( 2590 X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() == 2591 Context.getCanonicalTemplateName( 2592 Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer(); 2593 2594 case TemplateArgument::Integral: 2595 return hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral()); 2596 2597 case TemplateArgument::Expression: { 2598 llvm::FoldingSetNodeID XID, YID; 2599 X.getAsExpr()->Profile(XID, Context, true); 2600 Y.getAsExpr()->Profile(YID, Context, true); 2601 return XID == YID; 2602 } 2603 2604 case TemplateArgument::Pack: 2605 if (X.pack_size() != Y.pack_size()) 2606 return false; 2607 2608 for (TemplateArgument::pack_iterator XP = X.pack_begin(), 2609 XPEnd = X.pack_end(), 2610 YP = Y.pack_begin(); 2611 XP != XPEnd; ++XP, ++YP) 2612 if (!isSameTemplateArg(Context, *XP, *YP, PackExpansionMatchesPack)) 2613 return false; 2614 2615 return true; 2616 } 2617 2618 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable(); 2619} 2620 2621/// Allocate a TemplateArgumentLoc where all locations have 2622/// been initialized to the given location. 2623/// 2624/// \param Arg The template argument we are producing template argument 2625/// location information for. 2626/// 2627/// \param NTTPType For a declaration template argument, the type of 2628/// the non-type template parameter that corresponds to this template 2629/// argument. Can be null if no type sugar is available to add to the 2630/// type from the template argument. 2631/// 2632/// \param Loc The source location to use for the resulting template 2633/// argument. 2634TemplateArgumentLoc 2635Sema::getTrivialTemplateArgumentLoc(const TemplateArgument &Arg, 2636 QualType NTTPType, SourceLocation Loc) { 2637 switch (Arg.getKind()) { 2638 case TemplateArgument::Null: 2639 llvm_unreachable("Can't get a NULL template argument here")__builtin_unreachable(); 2640 2641 case TemplateArgument::Type: 2642 return TemplateArgumentLoc( 2643 Arg, Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); 2644 2645 case TemplateArgument::Declaration: { 2646 if (NTTPType.isNull()) 2647 NTTPType = Arg.getParamTypeForDecl(); 2648 Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 2649 .getAs<Expr>(); 2650 return TemplateArgumentLoc(TemplateArgument(E), E); 2651 } 2652 2653 case TemplateArgument::NullPtr: { 2654 if (NTTPType.isNull()) 2655 NTTPType = Arg.getNullPtrType(); 2656 Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 2657 .getAs<Expr>(); 2658 return TemplateArgumentLoc(TemplateArgument(NTTPType, /*isNullPtr*/true), 2659 E); 2660 } 2661 2662 case TemplateArgument::Integral: { 2663 Expr *E = 2664 BuildExpressionFromIntegralTemplateArgument(Arg, Loc).getAs<Expr>(); 2665 return TemplateArgumentLoc(TemplateArgument(E), E); 2666 } 2667 2668 case TemplateArgument::Template: 2669 case TemplateArgument::TemplateExpansion: { 2670 NestedNameSpecifierLocBuilder Builder; 2671 TemplateName Template = Arg.getAsTemplateOrTemplatePattern(); 2672 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) 2673 Builder.MakeTrivial(Context, DTN->getQualifier(), Loc); 2674 else if (QualifiedTemplateName *QTN = 2675 Template.getAsQualifiedTemplateName()) 2676 Builder.MakeTrivial(Context, QTN->getQualifier(), Loc); 2677 2678 if (Arg.getKind() == TemplateArgument::Template) 2679 return TemplateArgumentLoc(Context, Arg, 2680 Builder.getWithLocInContext(Context), Loc); 2681 2682 return TemplateArgumentLoc( 2683 Context, Arg, Builder.getWithLocInContext(Context), Loc, Loc); 2684 } 2685 2686 case TemplateArgument::Expression: 2687 return TemplateArgumentLoc(Arg, Arg.getAsExpr()); 2688 2689 case TemplateArgument::Pack: 2690 return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo()); 2691 } 2692 2693 llvm_unreachable("Invalid TemplateArgument Kind!")__builtin_unreachable(); 2694} 2695 2696TemplateArgumentLoc 2697Sema::getIdentityTemplateArgumentLoc(NamedDecl *TemplateParm, 2698 SourceLocation Location) { 2699 return getTrivialTemplateArgumentLoc( 2700 Context.getInjectedTemplateArg(TemplateParm), QualType(), Location); 2701} 2702 2703/// Convert the given deduced template argument and add it to the set of 2704/// fully-converted template arguments. 2705static bool 2706ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param, 2707 DeducedTemplateArgument Arg, 2708 NamedDecl *Template, 2709 TemplateDeductionInfo &Info, 2710 bool IsDeduced, 2711 SmallVectorImpl<TemplateArgument> &Output) { 2712 auto ConvertArg = [&](DeducedTemplateArgument Arg, 2713 unsigned ArgumentPackIndex) { 2714 // Convert the deduced template argument into a template 2715 // argument that we can check, almost as if the user had written 2716 // the template argument explicitly. 2717 TemplateArgumentLoc ArgLoc = 2718 S.getTrivialTemplateArgumentLoc(Arg, QualType(), Info.getLocation()); 2719 2720 // Check the template argument, converting it as necessary. 2721 return S.CheckTemplateArgument( 2722 Param, ArgLoc, Template, Template->getLocation(), 2723 Template->getSourceRange().getEnd(), ArgumentPackIndex, Output, 2724 IsDeduced 2725 ? (Arg.wasDeducedFromArrayBound() ? Sema::CTAK_DeducedFromArrayBound 2726 : Sema::CTAK_Deduced) 2727 : Sema::CTAK_Specified); 2728 }; 2729 2730 if (Arg.getKind() == TemplateArgument::Pack) { 2731 // This is a template argument pack, so check each of its arguments against 2732 // the template parameter. 2733 SmallVector<TemplateArgument, 2> PackedArgsBuilder; 2734 for (const auto &P : Arg.pack_elements()) { 2735 // When converting the deduced template argument, append it to the 2736 // general output list. We need to do this so that the template argument 2737 // checking logic has all of the prior template arguments available. 2738 DeducedTemplateArgument InnerArg(P); 2739 InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound()); 2740 assert(InnerArg.getKind() != TemplateArgument::Pack &&((void)0) 2741 "deduced nested pack")((void)0); 2742 if (P.isNull()) { 2743 // We deduced arguments for some elements of this pack, but not for 2744 // all of them. This happens if we get a conditionally-non-deduced 2745 // context in a pack expansion (such as an overload set in one of the 2746 // arguments). 2747 S.Diag(Param->getLocation(), 2748 diag::err_template_arg_deduced_incomplete_pack) 2749 << Arg << Param; 2750 return true; 2751 } 2752 if (ConvertArg(InnerArg, PackedArgsBuilder.size())) 2753 return true; 2754 2755 // Move the converted template argument into our argument pack. 2756 PackedArgsBuilder.push_back(Output.pop_back_val()); 2757 } 2758 2759 // If the pack is empty, we still need to substitute into the parameter 2760 // itself, in case that substitution fails. 2761 if (PackedArgsBuilder.empty()) { 2762 LocalInstantiationScope Scope(S); 2763 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Output); 2764 MultiLevelTemplateArgumentList Args(TemplateArgs); 2765 2766 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 2767 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template, 2768 NTTP, Output, 2769 Template->getSourceRange()); 2770 if (Inst.isInvalid() || 2771 S.SubstType(NTTP->getType(), Args, NTTP->getLocation(), 2772 NTTP->getDeclName()).isNull()) 2773 return true; 2774 } else if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param)) { 2775 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template, 2776 TTP, Output, 2777 Template->getSourceRange()); 2778 if (Inst.isInvalid() || !S.SubstDecl(TTP, S.CurContext, Args)) 2779 return true; 2780 } 2781 // For type parameters, no substitution is ever required. 2782 } 2783 2784 // Create the resulting argument pack. 2785 Output.push_back( 2786 TemplateArgument::CreatePackCopy(S.Context, PackedArgsBuilder)); 2787 return false; 2788 } 2789 2790 return ConvertArg(Arg, 0); 2791} 2792 2793// FIXME: This should not be a template, but 2794// ClassTemplatePartialSpecializationDecl sadly does not derive from 2795// TemplateDecl. 2796template<typename TemplateDeclT> 2797static Sema::TemplateDeductionResult ConvertDeducedTemplateArguments( 2798 Sema &S, TemplateDeclT *Template, bool IsDeduced, 2799 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2800 TemplateDeductionInfo &Info, SmallVectorImpl<TemplateArgument> &Builder, 2801 LocalInstantiationScope *CurrentInstantiationScope = nullptr, 2802 unsigned NumAlreadyConverted = 0, bool PartialOverloading = false) { 2803 TemplateParameterList *TemplateParams = Template->getTemplateParameters(); 2804 2805 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) { 2806 NamedDecl *Param = TemplateParams->getParam(I); 2807 2808 // C++0x [temp.arg.explicit]p3: 2809 // A trailing template parameter pack (14.5.3) not otherwise deduced will 2810 // be deduced to an empty sequence of template arguments. 2811 // FIXME: Where did the word "trailing" come from? 2812 if (Deduced[I].isNull() && Param->isTemplateParameterPack()) { 2813 if (auto Result = 2814 PackDeductionScope(S, TemplateParams, Deduced, Info, I).finish()) 2815 return Result; 2816 } 2817 2818 if (!Deduced[I].isNull()) { 2819 if (I < NumAlreadyConverted) { 2820 // We may have had explicitly-specified template arguments for a 2821 // template parameter pack (that may or may not have been extended 2822 // via additional deduced arguments). 2823 if (Param->isParameterPack() && CurrentInstantiationScope && 2824 CurrentInstantiationScope->getPartiallySubstitutedPack() == Param) { 2825 // Forget the partially-substituted pack; its substitution is now 2826 // complete. 2827 CurrentInstantiationScope->ResetPartiallySubstitutedPack(); 2828 // We still need to check the argument in case it was extended by 2829 // deduction. 2830 } else { 2831 // We have already fully type-checked and converted this 2832 // argument, because it was explicitly-specified. Just record the 2833 // presence of this argument. 2834 Builder.push_back(Deduced[I]); 2835 continue; 2836 } 2837 } 2838 2839 // We may have deduced this argument, so it still needs to be 2840 // checked and converted. 2841 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], Template, Info, 2842 IsDeduced, Builder)) { 2843 Info.Param = makeTemplateParameter(Param); 2844 // FIXME: These template arguments are temporary. Free them! 2845 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder)); 2846 return Sema::TDK_SubstitutionFailure; 2847 } 2848 2849 continue; 2850 } 2851 2852 // Substitute into the default template argument, if available. 2853 bool HasDefaultArg = false; 2854 TemplateDecl *TD = dyn_cast<TemplateDecl>(Template); 2855 if (!TD) { 2856 assert(isa<ClassTemplatePartialSpecializationDecl>(Template) ||((void)0) 2857 isa<VarTemplatePartialSpecializationDecl>(Template))((void)0); 2858 return Sema::TDK_Incomplete; 2859 } 2860 2861 TemplateArgumentLoc DefArg = S.SubstDefaultTemplateArgumentIfAvailable( 2862 TD, TD->getLocation(), TD->getSourceRange().getEnd(), Param, Builder, 2863 HasDefaultArg); 2864 2865 // If there was no default argument, deduction is incomplete. 2866 if (DefArg.getArgument().isNull()) { 2867 Info.Param = makeTemplateParameter( 2868 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 2869 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder)); 2870 if (PartialOverloading) break; 2871 2872 return HasDefaultArg ? Sema::TDK_SubstitutionFailure 2873 : Sema::TDK_Incomplete; 2874 } 2875 2876 // Check whether we can actually use the default argument. 2877 if (S.CheckTemplateArgument(Param, DefArg, TD, TD->getLocation(), 2878 TD->getSourceRange().getEnd(), 0, Builder, 2879 Sema::CTAK_Specified)) { 2880 Info.Param = makeTemplateParameter( 2881 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 2882 // FIXME: These template arguments are temporary. Free them! 2883 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder)); 2884 return Sema::TDK_SubstitutionFailure; 2885 } 2886 2887 // If we get here, we successfully used the default template argument. 2888 } 2889 2890 return Sema::TDK_Success; 2891} 2892 2893static DeclContext *getAsDeclContextOrEnclosing(Decl *D) { 2894 if (auto *DC = dyn_cast<DeclContext>(D)) 2895 return DC; 2896 return D->getDeclContext(); 2897} 2898 2899template<typename T> struct IsPartialSpecialization { 2900 static constexpr bool value = false; 2901}; 2902template<> 2903struct IsPartialSpecialization<ClassTemplatePartialSpecializationDecl> { 2904 static constexpr bool value = true; 2905}; 2906template<> 2907struct IsPartialSpecialization<VarTemplatePartialSpecializationDecl> { 2908 static constexpr bool value = true; 2909}; 2910 2911template<typename TemplateDeclT> 2912static Sema::TemplateDeductionResult 2913CheckDeducedArgumentConstraints(Sema& S, TemplateDeclT *Template, 2914 ArrayRef<TemplateArgument> DeducedArgs, 2915 TemplateDeductionInfo& Info) { 2916 llvm::SmallVector<const Expr *, 3> AssociatedConstraints; 2917 Template->getAssociatedConstraints(AssociatedConstraints); 2918 if (S.CheckConstraintSatisfaction(Template, AssociatedConstraints, 2919 DeducedArgs, Info.getLocation(), 2920 Info.AssociatedConstraintsSatisfaction) || 2921 !Info.AssociatedConstraintsSatisfaction.IsSatisfied) { 2922 Info.reset(TemplateArgumentList::CreateCopy(S.Context, DeducedArgs)); 2923 return Sema::TDK_ConstraintsNotSatisfied; 2924 } 2925 return Sema::TDK_Success; 2926} 2927 2928/// Complete template argument deduction for a partial specialization. 2929template <typename T> 2930static std::enable_if_t<IsPartialSpecialization<T>::value, 2931 Sema::TemplateDeductionResult> 2932FinishTemplateArgumentDeduction( 2933 Sema &S, T *Partial, bool IsPartialOrdering, 2934 const TemplateArgumentList &TemplateArgs, 2935 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2936 TemplateDeductionInfo &Info) { 2937 // Unevaluated SFINAE context. 2938 EnterExpressionEvaluationContext Unevaluated( 2939 S, Sema::ExpressionEvaluationContext::Unevaluated); 2940 Sema::SFINAETrap Trap(S); 2941 2942 Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Partial)); 2943 2944 // C++ [temp.deduct.type]p2: 2945 // [...] or if any template argument remains neither deduced nor 2946 // explicitly specified, template argument deduction fails. 2947 SmallVector<TemplateArgument, 4> Builder; 2948 if (auto Result = ConvertDeducedTemplateArguments( 2949 S, Partial, IsPartialOrdering, Deduced, Info, Builder)) 2950 return Result; 2951 2952 // Form the template argument list from the deduced template arguments. 2953 TemplateArgumentList *DeducedArgumentList 2954 = TemplateArgumentList::CreateCopy(S.Context, Builder); 2955 2956 Info.reset(DeducedArgumentList); 2957 2958 // Substitute the deduced template arguments into the template 2959 // arguments of the class template partial specialization, and 2960 // verify that the instantiated template arguments are both valid 2961 // and are equivalent to the template arguments originally provided 2962 // to the class template. 2963 LocalInstantiationScope InstScope(S); 2964 auto *Template = Partial->getSpecializedTemplate(); 2965 const ASTTemplateArgumentListInfo *PartialTemplArgInfo = 2966 Partial->getTemplateArgsAsWritten(); 2967 const TemplateArgumentLoc *PartialTemplateArgs = 2968 PartialTemplArgInfo->getTemplateArgs(); 2969 2970 TemplateArgumentListInfo InstArgs(PartialTemplArgInfo->LAngleLoc, 2971 PartialTemplArgInfo->RAngleLoc); 2972 2973 if (S.Subst(PartialTemplateArgs, PartialTemplArgInfo->NumTemplateArgs, 2974 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) { 2975 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx; 2976 if (ParamIdx >= Partial->getTemplateParameters()->size()) 2977 ParamIdx = Partial->getTemplateParameters()->size() - 1; 2978 2979 Decl *Param = const_cast<NamedDecl *>( 2980 Partial->getTemplateParameters()->getParam(ParamIdx)); 2981 Info.Param = makeTemplateParameter(Param); 2982 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument(); 2983 return Sema::TDK_SubstitutionFailure; 2984 } 2985 2986 bool ConstraintsNotSatisfied; 2987 SmallVector<TemplateArgument, 4> ConvertedInstArgs; 2988 if (S.CheckTemplateArgumentList(Template, Partial->getLocation(), InstArgs, 2989 false, ConvertedInstArgs, 2990 /*UpdateArgsWithConversions=*/true, 2991 &ConstraintsNotSatisfied)) 2992 return ConstraintsNotSatisfied ? Sema::TDK_ConstraintsNotSatisfied : 2993 Sema::TDK_SubstitutionFailure; 2994 2995 TemplateParameterList *TemplateParams = Template->getTemplateParameters(); 2996 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) { 2997 TemplateArgument InstArg = ConvertedInstArgs.data()[I]; 2998 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) { 2999 Info.Param = makeTemplateParameter(TemplateParams->getParam(I)); 3000 Info.FirstArg = TemplateArgs[I]; 3001 Info.SecondArg = InstArg; 3002 return Sema::TDK_NonDeducedMismatch; 3003 } 3004 } 3005 3006 if (Trap.hasErrorOccurred()) 3007 return Sema::TDK_SubstitutionFailure; 3008 3009 if (auto Result = CheckDeducedArgumentConstraints(S, Partial, Builder, Info)) 3010 return Result; 3011 3012 return Sema::TDK_Success; 3013} 3014 3015/// Complete template argument deduction for a class or variable template, 3016/// when partial ordering against a partial specialization. 3017// FIXME: Factor out duplication with partial specialization version above. 3018static Sema::TemplateDeductionResult FinishTemplateArgumentDeduction( 3019 Sema &S, TemplateDecl *Template, bool PartialOrdering, 3020 const TemplateArgumentList &TemplateArgs, 3021 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 3022 TemplateDeductionInfo &Info) { 3023 // Unevaluated SFINAE context. 3024 EnterExpressionEvaluationContext Unevaluated( 3025 S, Sema::ExpressionEvaluationContext::Unevaluated); 3026 Sema::SFINAETrap Trap(S); 3027 3028 Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Template)); 3029 3030 // C++ [temp.deduct.type]p2: 3031 // [...] or if any template argument remains neither deduced nor 3032 // explicitly specified, template argument deduction fails. 3033 SmallVector<TemplateArgument, 4> Builder; 3034 if (auto Result = ConvertDeducedTemplateArguments( 3035 S, Template, /*IsDeduced*/PartialOrdering, Deduced, Info, Builder)) 3036 return Result; 3037 3038 // Check that we produced the correct argument list. 3039 TemplateParameterList *TemplateParams = Template->getTemplateParameters(); 3040 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) { 3041 TemplateArgument InstArg = Builder[I]; 3042 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg, 3043 /*PackExpansionMatchesPack*/true)) { 3044 Info.Param = makeTemplateParameter(TemplateParams->getParam(I)); 3045 Info.FirstArg = TemplateArgs[I]; 3046 Info.SecondArg = InstArg; 3047 return Sema::TDK_NonDeducedMismatch; 3048 } 3049 } 3050 3051 if (Trap.hasErrorOccurred()) 3052 return Sema::TDK_SubstitutionFailure; 3053 3054 if (auto Result = CheckDeducedArgumentConstraints(S, Template, Builder, 3055 Info)) 3056 return Result; 3057 3058 return Sema::TDK_Success; 3059} 3060 3061/// Perform template argument deduction to determine whether 3062/// the given template arguments match the given class template 3063/// partial specialization per C++ [temp.class.spec.match]. 3064Sema::TemplateDeductionResult 3065Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, 3066 const TemplateArgumentList &TemplateArgs, 3067 TemplateDeductionInfo &Info) { 3068 if (Partial->isInvalidDecl()) 3069 return TDK_Invalid; 3070 3071 // C++ [temp.class.spec.match]p2: 3072 // A partial specialization matches a given actual template 3073 // argument list if the template arguments of the partial 3074 // specialization can be deduced from the actual template argument 3075 // list (14.8.2). 3076 3077 // Unevaluated SFINAE context. 3078 EnterExpressionEvaluationContext Unevaluated( 3079 *this, Sema::ExpressionEvaluationContext::Unevaluated); 3080 SFINAETrap Trap(*this); 3081 3082 // This deduction has no relation to any outer instantiation we might be 3083 // performing. 3084 LocalInstantiationScope InstantiationScope(*this); 3085 3086 SmallVector<DeducedTemplateArgument, 4> Deduced; 3087 Deduced.resize(Partial->getTemplateParameters()->size()); 3088 if (TemplateDeductionResult Result 3089 = ::DeduceTemplateArguments(*this, 3090 Partial->getTemplateParameters(), 3091 Partial->getTemplateArgs(), 3092 TemplateArgs, Info, Deduced)) 3093 return Result; 3094 3095 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end()); 3096 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs, 3097 Info); 3098 if (Inst.isInvalid()) 3099 return TDK_InstantiationDepth; 3100 3101 if (Trap.hasErrorOccurred()) 3102 return Sema::TDK_SubstitutionFailure; 3103 3104 TemplateDeductionResult Result; 3105 runWithSufficientStackSpace(Info.getLocation(), [&] { 3106 Result = ::FinishTemplateArgumentDeduction(*this, Partial, 3107 /*IsPartialOrdering=*/false, 3108 TemplateArgs, Deduced, Info); 3109 }); 3110 return Result; 3111} 3112 3113/// Perform template argument deduction to determine whether 3114/// the given template arguments match the given variable template 3115/// partial specialization per C++ [temp.class.spec.match]. 3116Sema::TemplateDeductionResult 3117Sema::DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial, 3118 const TemplateArgumentList &TemplateArgs, 3119 TemplateDeductionInfo &Info) { 3120 if (Partial->isInvalidDecl()) 3121 return TDK_Invalid; 3122 3123 // C++ [temp.class.spec.match]p2: 3124 // A partial specialization matches a given actual template 3125 // argument list if the template arguments of the partial 3126 // specialization can be deduced from the actual template argument 3127 // list (14.8.2). 3128 3129 // Unevaluated SFINAE context. 3130 EnterExpressionEvaluationContext Unevaluated( 3131 *this, Sema::ExpressionEvaluationContext::Unevaluated); 3132 SFINAETrap Trap(*this); 3133 3134 // This deduction has no relation to any outer instantiation we might be 3135 // performing. 3136 LocalInstantiationScope InstantiationScope(*this); 3137 3138 SmallVector<DeducedTemplateArgument, 4> Deduced; 3139 Deduced.resize(Partial->getTemplateParameters()->size()); 3140 if (TemplateDeductionResult Result = ::DeduceTemplateArguments( 3141 *this, Partial->getTemplateParameters(), Partial->getTemplateArgs(), 3142 TemplateArgs, Info, Deduced)) 3143 return Result; 3144 3145 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end()); 3146 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs, 3147 Info); 3148 if (Inst.isInvalid()) 3149 return TDK_InstantiationDepth; 3150 3151 if (Trap.hasErrorOccurred()) 3152 return Sema::TDK_SubstitutionFailure; 3153 3154 TemplateDeductionResult Result; 3155 runWithSufficientStackSpace(Info.getLocation(), [&] { 3156 Result = ::FinishTemplateArgumentDeduction(*this, Partial, 3157 /*IsPartialOrdering=*/false, 3158 TemplateArgs, Deduced, Info); 3159 }); 3160 return Result; 3161} 3162 3163/// Determine whether the given type T is a simple-template-id type. 3164static bool isSimpleTemplateIdType(QualType T) { 3165 if (const TemplateSpecializationType *Spec 3166 = T->getAs<TemplateSpecializationType>()) 3167 return Spec->getTemplateName().getAsTemplateDecl() != nullptr; 3168 3169 // C++17 [temp.local]p2: 3170 // the injected-class-name [...] is equivalent to the template-name followed 3171 // by the template-arguments of the class template specialization or partial 3172 // specialization enclosed in <> 3173 // ... which means it's equivalent to a simple-template-id. 3174 // 3175 // This only arises during class template argument deduction for a copy 3176 // deduction candidate, where it permits slicing. 3177 if (T->getAs<InjectedClassNameType>()) 3178 return true; 3179 3180 return false; 3181} 3182 3183/// Substitute the explicitly-provided template arguments into the 3184/// given function template according to C++ [temp.arg.explicit]. 3185/// 3186/// \param FunctionTemplate the function template into which the explicit 3187/// template arguments will be substituted. 3188/// 3189/// \param ExplicitTemplateArgs the explicitly-specified template 3190/// arguments. 3191/// 3192/// \param Deduced the deduced template arguments, which will be populated 3193/// with the converted and checked explicit template arguments. 3194/// 3195/// \param ParamTypes will be populated with the instantiated function 3196/// parameters. 3197/// 3198/// \param FunctionType if non-NULL, the result type of the function template 3199/// will also be instantiated and the pointed-to value will be updated with 3200/// the instantiated function type. 3201/// 3202/// \param Info if substitution fails for any reason, this object will be 3203/// populated with more information about the failure. 3204/// 3205/// \returns TDK_Success if substitution was successful, or some failure 3206/// condition. 3207Sema::TemplateDeductionResult 3208Sema::SubstituteExplicitTemplateArguments( 3209 FunctionTemplateDecl *FunctionTemplate, 3210 TemplateArgumentListInfo &ExplicitTemplateArgs, 3211 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 3212 SmallVectorImpl<QualType> &ParamTypes, 3213 QualType *FunctionType, 3214 TemplateDeductionInfo &Info) { 3215 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 3216 TemplateParameterList *TemplateParams 3217 = FunctionTemplate->getTemplateParameters(); 3218 3219 if (ExplicitTemplateArgs.size() == 0) { 3220 // No arguments to substitute; just copy over the parameter types and 3221 // fill in the function type. 3222 for (auto P : Function->parameters()) 3223 ParamTypes.push_back(P->getType()); 3224 3225 if (FunctionType) 3226 *FunctionType = Function->getType(); 3227 return TDK_Success; 3228 } 3229 3230 // Unevaluated SFINAE context. 3231 EnterExpressionEvaluationContext Unevaluated( 3232 *this, Sema::ExpressionEvaluationContext::Unevaluated); 3233 SFINAETrap Trap(*this); 3234 3235 // C++ [temp.arg.explicit]p3: 3236 // Template arguments that are present shall be specified in the 3237 // declaration order of their corresponding template-parameters. The 3238 // template argument list shall not specify more template-arguments than 3239 // there are corresponding template-parameters. 3240 SmallVector<TemplateArgument, 4> Builder; 3241 3242 // Enter a new template instantiation context where we check the 3243 // explicitly-specified template arguments against this function template, 3244 // and then substitute them into the function parameter types. 3245 SmallVector<TemplateArgument, 4> DeducedArgs; 3246 InstantiatingTemplate Inst( 3247 *this, Info.getLocation(), FunctionTemplate, DeducedArgs, 3248 CodeSynthesisContext::ExplicitTemplateArgumentSubstitution, Info); 3249 if (Inst.isInvalid()) 3250 return TDK_InstantiationDepth; 3251 3252 if (CheckTemplateArgumentList(FunctionTemplate, SourceLocation(), 3253 ExplicitTemplateArgs, true, Builder, false) || 3254 Trap.hasErrorOccurred()) { 3255 unsigned Index = Builder.size(); 3256 if (Index >= TemplateParams->size()) 3257 return TDK_SubstitutionFailure; 3258 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index)); 3259 return TDK_InvalidExplicitArguments; 3260 } 3261 3262 // Form the template argument list from the explicitly-specified 3263 // template arguments. 3264 TemplateArgumentList *ExplicitArgumentList 3265 = TemplateArgumentList::CreateCopy(Context, Builder); 3266 Info.setExplicitArgs(ExplicitArgumentList); 3267 3268 // Template argument deduction and the final substitution should be 3269 // done in the context of the templated declaration. Explicit 3270 // argument substitution, on the other hand, needs to happen in the 3271 // calling context. 3272 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 3273 3274 // If we deduced template arguments for a template parameter pack, 3275 // note that the template argument pack is partially substituted and record 3276 // the explicit template arguments. They'll be used as part of deduction 3277 // for this template parameter pack. 3278 unsigned PartiallySubstitutedPackIndex = -1u; 3279 if (!Builder.empty()) { 3280 const TemplateArgument &Arg = Builder.back(); 3281 if (Arg.getKind() == TemplateArgument::Pack) { 3282 auto *Param = TemplateParams->getParam(Builder.size() - 1); 3283 // If this is a fully-saturated fixed-size pack, it should be 3284 // fully-substituted, not partially-substituted. 3285 Optional<unsigned> Expansions = getExpandedPackSize(Param); 3286 if (!Expansions || Arg.pack_size() < *Expansions) { 3287 PartiallySubstitutedPackIndex = Builder.size() - 1; 3288 CurrentInstantiationScope->SetPartiallySubstitutedPack( 3289 Param, Arg.pack_begin(), Arg.pack_size()); 3290 } 3291 } 3292 } 3293 3294 const FunctionProtoType *Proto 3295 = Function->getType()->getAs<FunctionProtoType>(); 3296 assert(Proto && "Function template does not have a prototype?")((void)0); 3297 3298 // Isolate our substituted parameters from our caller. 3299 LocalInstantiationScope InstScope(*this, /*MergeWithOuterScope*/true); 3300 3301 ExtParameterInfoBuilder ExtParamInfos; 3302 3303 // Instantiate the types of each of the function parameters given the 3304 // explicitly-specified template arguments. If the function has a trailing 3305 // return type, substitute it after the arguments to ensure we substitute 3306 // in lexical order. 3307 if (Proto->hasTrailingReturn()) { 3308 if (SubstParmTypes(Function->getLocation(), Function->parameters(), 3309 Proto->getExtParameterInfosOrNull(), 3310 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 3311 ParamTypes, /*params*/ nullptr, ExtParamInfos)) 3312 return TDK_SubstitutionFailure; 3313 } 3314 3315 // Instantiate the return type. 3316 QualType ResultType; 3317 { 3318 // C++11 [expr.prim.general]p3: 3319 // If a declaration declares a member function or member function 3320 // template of a class X, the expression this is a prvalue of type 3321 // "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq 3322 // and the end of the function-definition, member-declarator, or 3323 // declarator. 3324 Qualifiers ThisTypeQuals; 3325 CXXRecordDecl *ThisContext = nullptr; 3326 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 3327 ThisContext = Method->getParent(); 3328 ThisTypeQuals = Method->getMethodQualifiers(); 3329 } 3330 3331 CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals, 3332 getLangOpts().CPlusPlus11); 3333 3334 ResultType = 3335 SubstType(Proto->getReturnType(), 3336 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 3337 Function->getTypeSpecStartLoc(), Function->getDeclName()); 3338 if (ResultType.isNull() || Trap.hasErrorOccurred()) 3339 return TDK_SubstitutionFailure; 3340 // CUDA: Kernel function must have 'void' return type. 3341 if (getLangOpts().CUDA) 3342 if (Function->hasAttr<CUDAGlobalAttr>() && !ResultType->isVoidType()) { 3343 Diag(Function->getLocation(), diag::err_kern_type_not_void_return) 3344 << Function->getType() << Function->getSourceRange(); 3345 return TDK_SubstitutionFailure; 3346 } 3347 } 3348 3349 // Instantiate the types of each of the function parameters given the 3350 // explicitly-specified template arguments if we didn't do so earlier. 3351 if (!Proto->hasTrailingReturn() && 3352 SubstParmTypes(Function->getLocation(), Function->parameters(), 3353 Proto->getExtParameterInfosOrNull(), 3354 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 3355 ParamTypes, /*params*/ nullptr, ExtParamInfos)) 3356 return TDK_SubstitutionFailure; 3357 3358 if (FunctionType) { 3359 auto EPI = Proto->getExtProtoInfo(); 3360 EPI.ExtParameterInfos = ExtParamInfos.getPointerOrNull(ParamTypes.size()); 3361 3362 // In C++1z onwards, exception specifications are part of the function type, 3363 // so substitution into the type must also substitute into the exception 3364 // specification. 3365 SmallVector<QualType, 4> ExceptionStorage; 3366 if (getLangOpts().CPlusPlus17 && 3367 SubstExceptionSpec( 3368 Function->getLocation(), EPI.ExceptionSpec, ExceptionStorage, 3369 MultiLevelTemplateArgumentList(*ExplicitArgumentList))) 3370 return TDK_SubstitutionFailure; 3371 3372 *FunctionType = BuildFunctionType(ResultType, ParamTypes, 3373 Function->getLocation(), 3374 Function->getDeclName(), 3375 EPI); 3376 if (FunctionType->isNull() || Trap.hasErrorOccurred()) 3377 return TDK_SubstitutionFailure; 3378 } 3379 3380 // C++ [temp.arg.explicit]p2: 3381 // Trailing template arguments that can be deduced (14.8.2) may be 3382 // omitted from the list of explicit template-arguments. If all of the 3383 // template arguments can be deduced, they may all be omitted; in this 3384 // case, the empty template argument list <> itself may also be omitted. 3385 // 3386 // Take all of the explicitly-specified arguments and put them into 3387 // the set of deduced template arguments. The partially-substituted 3388 // parameter pack, however, will be set to NULL since the deduction 3389 // mechanism handles the partially-substituted argument pack directly. 3390 Deduced.reserve(TemplateParams->size()); 3391 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) { 3392 const TemplateArgument &Arg = ExplicitArgumentList->get(I); 3393 if (I == PartiallySubstitutedPackIndex) 3394 Deduced.push_back(DeducedTemplateArgument()); 3395 else 3396 Deduced.push_back(Arg); 3397 } 3398 3399 return TDK_Success; 3400} 3401 3402/// Check whether the deduced argument type for a call to a function 3403/// template matches the actual argument type per C++ [temp.deduct.call]p4. 3404static Sema::TemplateDeductionResult 3405CheckOriginalCallArgDeduction(Sema &S, TemplateDeductionInfo &Info, 3406 Sema::OriginalCallArg OriginalArg, 3407 QualType DeducedA) { 3408 ASTContext &Context = S.Context; 3409 3410 auto Failed = [&]() -> Sema::TemplateDeductionResult { 3411 Info.FirstArg = TemplateArgument(DeducedA); 3412 Info.SecondArg = TemplateArgument(OriginalArg.OriginalArgType); 3413 Info.CallArgIndex = OriginalArg.ArgIdx; 3414 return OriginalArg.DecomposedParam ? Sema::TDK_DeducedMismatchNested 3415 : Sema::TDK_DeducedMismatch; 3416 }; 3417 3418 QualType A = OriginalArg.OriginalArgType; 3419 QualType OriginalParamType = OriginalArg.OriginalParamType; 3420 3421 // Check for type equality (top-level cv-qualifiers are ignored). 3422 if (Context.hasSameUnqualifiedType(A, DeducedA)) 3423 return Sema::TDK_Success; 3424 3425 // Strip off references on the argument types; they aren't needed for 3426 // the following checks. 3427 if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>()) 3428 DeducedA = DeducedARef->getPointeeType(); 3429 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 3430 A = ARef->getPointeeType(); 3431 3432 // C++ [temp.deduct.call]p4: 3433 // [...] However, there are three cases that allow a difference: 3434 // - If the original P is a reference type, the deduced A (i.e., the 3435 // type referred to by the reference) can be more cv-qualified than 3436 // the transformed A. 3437 if (const ReferenceType *OriginalParamRef 3438 = OriginalParamType->getAs<ReferenceType>()) { 3439 // We don't want to keep the reference around any more. 3440 OriginalParamType = OriginalParamRef->getPointeeType(); 3441 3442 // FIXME: Resolve core issue (no number yet): if the original P is a 3443 // reference type and the transformed A is function type "noexcept F", 3444 // the deduced A can be F. 3445 QualType Tmp; 3446 if (A->isFunctionType() && S.IsFunctionConversion(A, DeducedA, Tmp)) 3447 return Sema::TDK_Success; 3448 3449 Qualifiers AQuals = A.getQualifiers(); 3450 Qualifiers DeducedAQuals = DeducedA.getQualifiers(); 3451 3452 // Under Objective-C++ ARC, the deduced type may have implicitly 3453 // been given strong or (when dealing with a const reference) 3454 // unsafe_unretained lifetime. If so, update the original 3455 // qualifiers to include this lifetime. 3456 if (S.getLangOpts().ObjCAutoRefCount && 3457 ((DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_Strong && 3458 AQuals.getObjCLifetime() == Qualifiers::OCL_None) || 3459 (DeducedAQuals.hasConst() && 3460 DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone))) { 3461 AQuals.setObjCLifetime(DeducedAQuals.getObjCLifetime()); 3462 } 3463 3464 if (AQuals == DeducedAQuals) { 3465 // Qualifiers match; there's nothing to do. 3466 } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) { 3467 return Failed(); 3468 } else { 3469 // Qualifiers are compatible, so have the argument type adopt the 3470 // deduced argument type's qualifiers as if we had performed the 3471 // qualification conversion. 3472 A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals); 3473 } 3474 } 3475 3476 // - The transformed A can be another pointer or pointer to member 3477 // type that can be converted to the deduced A via a function pointer 3478 // conversion and/or a qualification conversion. 3479 // 3480 // Also allow conversions which merely strip __attribute__((noreturn)) from 3481 // function types (recursively). 3482 bool ObjCLifetimeConversion = false; 3483 QualType ResultTy; 3484 if ((A->isAnyPointerType() || A->isMemberPointerType()) && 3485 (S.IsQualificationConversion(A, DeducedA, false, 3486 ObjCLifetimeConversion) || 3487 S.IsFunctionConversion(A, DeducedA, ResultTy))) 3488 return Sema::TDK_Success; 3489 3490 // - If P is a class and P has the form simple-template-id, then the 3491 // transformed A can be a derived class of the deduced A. [...] 3492 // [...] Likewise, if P is a pointer to a class of the form 3493 // simple-template-id, the transformed A can be a pointer to a 3494 // derived class pointed to by the deduced A. 3495 if (const PointerType *OriginalParamPtr 3496 = OriginalParamType->getAs<PointerType>()) { 3497 if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) { 3498 if (const PointerType *APtr = A->getAs<PointerType>()) { 3499 if (A->getPointeeType()->isRecordType()) { 3500 OriginalParamType = OriginalParamPtr->getPointeeType(); 3501 DeducedA = DeducedAPtr->getPointeeType(); 3502 A = APtr->getPointeeType(); 3503 } 3504 } 3505 } 3506 } 3507 3508 if (Context.hasSameUnqualifiedType(A, DeducedA)) 3509 return Sema::TDK_Success; 3510 3511 if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) && 3512 S.IsDerivedFrom(Info.getLocation(), A, DeducedA)) 3513 return Sema::TDK_Success; 3514 3515 return Failed(); 3516} 3517 3518/// Find the pack index for a particular parameter index in an instantiation of 3519/// a function template with specific arguments. 3520/// 3521/// \return The pack index for whichever pack produced this parameter, or -1 3522/// if this was not produced by a parameter. Intended to be used as the 3523/// ArgumentPackSubstitutionIndex for further substitutions. 3524// FIXME: We should track this in OriginalCallArgs so we don't need to 3525// reconstruct it here. 3526static unsigned getPackIndexForParam(Sema &S, 3527 FunctionTemplateDecl *FunctionTemplate, 3528 const MultiLevelTemplateArgumentList &Args, 3529 unsigned ParamIdx) { 3530 unsigned Idx = 0; 3531 for (auto *PD : FunctionTemplate->getTemplatedDecl()->parameters()) { 3532 if (PD->isParameterPack()) { 3533 unsigned NumExpansions = 3534 S.getNumArgumentsInExpansion(PD->getType(), Args).getValueOr(1); 3535 if (Idx + NumExpansions > ParamIdx) 3536 return ParamIdx - Idx; 3537 Idx += NumExpansions; 3538 } else { 3539 if (Idx == ParamIdx) 3540 return -1; // Not a pack expansion 3541 ++Idx; 3542 } 3543 } 3544 3545 llvm_unreachable("parameter index would not be produced from template")__builtin_unreachable(); 3546} 3547 3548/// Finish template argument deduction for a function template, 3549/// checking the deduced template arguments for completeness and forming 3550/// the function template specialization. 3551/// 3552/// \param OriginalCallArgs If non-NULL, the original call arguments against 3553/// which the deduced argument types should be compared. 3554Sema::TemplateDeductionResult Sema::FinishTemplateArgumentDeduction( 3555 FunctionTemplateDecl *FunctionTemplate, 3556 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 3557 unsigned NumExplicitlySpecified, FunctionDecl *&Specialization, 3558 TemplateDeductionInfo &Info, 3559 SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs, 3560 bool PartialOverloading, llvm::function_ref<bool()> CheckNonDependent) { 3561 // Unevaluated SFINAE context. 3562 EnterExpressionEvaluationContext Unevaluated( 3563 *this, Sema::ExpressionEvaluationContext::Unevaluated); 3564 SFINAETrap Trap(*this); 3565 3566 // Enter a new template instantiation context while we instantiate the 3567 // actual function declaration. 3568 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end()); 3569 InstantiatingTemplate Inst( 3570 *this, Info.getLocation(), FunctionTemplate, DeducedArgs, 3571 CodeSynthesisContext::DeducedTemplateArgumentSubstitution, Info); 3572 if (Inst.isInvalid()) 3573 return TDK_InstantiationDepth; 3574 3575 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 3576 3577 // C++ [temp.deduct.type]p2: 3578 // [...] or if any template argument remains neither deduced nor 3579 // explicitly specified, template argument deduction fails. 3580 SmallVector<TemplateArgument, 4> Builder; 3581 if (auto Result = ConvertDeducedTemplateArguments( 3582 *this, FunctionTemplate, /*IsDeduced*/true, Deduced, Info, Builder, 3583 CurrentInstantiationScope, NumExplicitlySpecified, 3584 PartialOverloading)) 3585 return Result; 3586 3587 // C++ [temp.deduct.call]p10: [DR1391] 3588 // If deduction succeeds for all parameters that contain 3589 // template-parameters that participate in template argument deduction, 3590 // and all template arguments are explicitly specified, deduced, or 3591 // obtained from default template arguments, remaining parameters are then 3592 // compared with the corresponding arguments. For each remaining parameter 3593 // P with a type that was non-dependent before substitution of any 3594 // explicitly-specified template arguments, if the corresponding argument 3595 // A cannot be implicitly converted to P, deduction fails. 3596 if (CheckNonDependent()) 3597 return TDK_NonDependentConversionFailure; 3598 3599 // Form the template argument list from the deduced template arguments. 3600 TemplateArgumentList *DeducedArgumentList 3601 = TemplateArgumentList::CreateCopy(Context, Builder); 3602 Info.reset(DeducedArgumentList); 3603 3604 // Substitute the deduced template arguments into the function template 3605 // declaration to produce the function template specialization. 3606 DeclContext *Owner = FunctionTemplate->getDeclContext(); 3607 if (FunctionTemplate->getFriendObjectKind()) 3608 Owner = FunctionTemplate->getLexicalDeclContext(); 3609 MultiLevelTemplateArgumentList SubstArgs(*DeducedArgumentList); 3610 Specialization = cast_or_null<FunctionDecl>( 3611 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, SubstArgs)); 3612 if (!Specialization || Specialization->isInvalidDecl()) 3613 return TDK_SubstitutionFailure; 3614 3615 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() ==((void)0) 3616 FunctionTemplate->getCanonicalDecl())((void)0); 3617 3618 // If the template argument list is owned by the function template 3619 // specialization, release it. 3620 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList && 3621 !Trap.hasErrorOccurred()) 3622 Info.take(); 3623 3624 // There may have been an error that did not prevent us from constructing a 3625 // declaration. Mark the declaration invalid and return with a substitution 3626 // failure. 3627 if (Trap.hasErrorOccurred()) { 3628 Specialization->setInvalidDecl(true); 3629 return TDK_SubstitutionFailure; 3630 } 3631 3632 // C++2a [temp.deduct]p5 3633 // [...] When all template arguments have been deduced [...] all uses of 3634 // template parameters [...] are replaced with the corresponding deduced 3635 // or default argument values. 3636 // [...] If the function template has associated constraints 3637 // ([temp.constr.decl]), those constraints are checked for satisfaction 3638 // ([temp.constr.constr]). If the constraints are not satisfied, type 3639 // deduction fails. 3640 if (!PartialOverloading || 3641 (Builder.size() == FunctionTemplate->getTemplateParameters()->size())) { 3642 if (CheckInstantiatedFunctionTemplateConstraints(Info.getLocation(), 3643 Specialization, Builder, Info.AssociatedConstraintsSatisfaction)) 3644 return TDK_MiscellaneousDeductionFailure; 3645 3646 if (!Info.AssociatedConstraintsSatisfaction.IsSatisfied) { 3647 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder)); 3648 return TDK_ConstraintsNotSatisfied; 3649 } 3650 } 3651 3652 if (OriginalCallArgs) { 3653 // C++ [temp.deduct.call]p4: 3654 // In general, the deduction process attempts to find template argument 3655 // values that will make the deduced A identical to A (after the type A 3656 // is transformed as described above). [...] 3657 llvm::SmallDenseMap<std::pair<unsigned, QualType>, QualType> DeducedATypes; 3658 for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) { 3659 OriginalCallArg OriginalArg = (*OriginalCallArgs)[I]; 3660 3661 auto ParamIdx = OriginalArg.ArgIdx; 3662 if (ParamIdx >= Specialization->getNumParams()) 3663 // FIXME: This presumably means a pack ended up smaller than we 3664 // expected while deducing. Should this not result in deduction 3665 // failure? Can it even happen? 3666 continue; 3667 3668 QualType DeducedA; 3669 if (!OriginalArg.DecomposedParam) { 3670 // P is one of the function parameters, just look up its substituted 3671 // type. 3672 DeducedA = Specialization->getParamDecl(ParamIdx)->getType(); 3673 } else { 3674 // P is a decomposed element of a parameter corresponding to a 3675 // braced-init-list argument. Substitute back into P to find the 3676 // deduced A. 3677 QualType &CacheEntry = 3678 DeducedATypes[{ParamIdx, OriginalArg.OriginalParamType}]; 3679 if (CacheEntry.isNull()) { 3680 ArgumentPackSubstitutionIndexRAII PackIndex( 3681 *this, getPackIndexForParam(*this, FunctionTemplate, SubstArgs, 3682 ParamIdx)); 3683 CacheEntry = 3684 SubstType(OriginalArg.OriginalParamType, SubstArgs, 3685 Specialization->getTypeSpecStartLoc(), 3686 Specialization->getDeclName()); 3687 } 3688 DeducedA = CacheEntry; 3689 } 3690 3691 if (auto TDK = 3692 CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA)) 3693 return TDK; 3694 } 3695 } 3696 3697 // If we suppressed any diagnostics while performing template argument 3698 // deduction, and if we haven't already instantiated this declaration, 3699 // keep track of these diagnostics. They'll be emitted if this specialization 3700 // is actually used. 3701 if (Info.diag_begin() != Info.diag_end()) { 3702 SuppressedDiagnosticsMap::iterator 3703 Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl()); 3704 if (Pos == SuppressedDiagnostics.end()) 3705 SuppressedDiagnostics[Specialization->getCanonicalDecl()] 3706 .append(Info.diag_begin(), Info.diag_end()); 3707 } 3708 3709 return TDK_Success; 3710} 3711 3712/// Gets the type of a function for template-argument-deducton 3713/// purposes when it's considered as part of an overload set. 3714static QualType GetTypeOfFunction(Sema &S, const OverloadExpr::FindResult &R, 3715 FunctionDecl *Fn) { 3716 // We may need to deduce the return type of the function now. 3717 if (S.getLangOpts().CPlusPlus14 && Fn->getReturnType()->isUndeducedType() && 3718 S.DeduceReturnType(Fn, R.Expression->getExprLoc(), /*Diagnose*/ false)) 3719 return {}; 3720 3721 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) 3722 if (Method->isInstance()) { 3723 // An instance method that's referenced in a form that doesn't 3724 // look like a member pointer is just invalid. 3725 if (!R.HasFormOfMemberPointer) 3726 return {}; 3727 3728 return S.Context.getMemberPointerType(Fn->getType(), 3729 S.Context.getTypeDeclType(Method->getParent()).getTypePtr()); 3730 } 3731 3732 if (!R.IsAddressOfOperand) return Fn->getType(); 3733 return S.Context.getPointerType(Fn->getType()); 3734} 3735 3736/// Apply the deduction rules for overload sets. 3737/// 3738/// \return the null type if this argument should be treated as an 3739/// undeduced context 3740static QualType 3741ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, 3742 Expr *Arg, QualType ParamType, 3743 bool ParamWasReference) { 3744 3745 OverloadExpr::FindResult R = OverloadExpr::find(Arg); 3746 3747 OverloadExpr *Ovl = R.Expression; 3748 3749 // C++0x [temp.deduct.call]p4 3750 unsigned TDF = 0; 3751 if (ParamWasReference) 3752 TDF |= TDF_ParamWithReferenceType; 3753 if (R.IsAddressOfOperand) 3754 TDF |= TDF_IgnoreQualifiers; 3755 3756 // C++0x [temp.deduct.call]p6: 3757 // When P is a function type, pointer to function type, or pointer 3758 // to member function type: 3759 3760 if (!ParamType->isFunctionType() && 3761 !ParamType->isFunctionPointerType() && 3762 !ParamType->isMemberFunctionPointerType()) { 3763 if (Ovl->hasExplicitTemplateArgs()) { 3764 // But we can still look for an explicit specialization. 3765 if (FunctionDecl *ExplicitSpec 3766 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 3767 return GetTypeOfFunction(S, R, ExplicitSpec); 3768 } 3769 3770 DeclAccessPair DAP; 3771 if (FunctionDecl *Viable = 3772 S.resolveAddressOfSingleOverloadCandidate(Arg, DAP)) 3773 return GetTypeOfFunction(S, R, Viable); 3774 3775 return {}; 3776 } 3777 3778 // Gather the explicit template arguments, if any. 3779 TemplateArgumentListInfo ExplicitTemplateArgs; 3780 if (Ovl->hasExplicitTemplateArgs()) 3781 Ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs); 3782 QualType Match; 3783 for (UnresolvedSetIterator I = Ovl->decls_begin(), 3784 E = Ovl->decls_end(); I != E; ++I) { 3785 NamedDecl *D = (*I)->getUnderlyingDecl(); 3786 3787 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) { 3788 // - If the argument is an overload set containing one or more 3789 // function templates, the parameter is treated as a 3790 // non-deduced context. 3791 if (!Ovl->hasExplicitTemplateArgs()) 3792 return {}; 3793 3794 // Otherwise, see if we can resolve a function type 3795 FunctionDecl *Specialization = nullptr; 3796 TemplateDeductionInfo Info(Ovl->getNameLoc()); 3797 if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs, 3798 Specialization, Info)) 3799 continue; 3800 3801 D = Specialization; 3802 } 3803 3804 FunctionDecl *Fn = cast<FunctionDecl>(D); 3805 QualType ArgType = GetTypeOfFunction(S, R, Fn); 3806 if (ArgType.isNull()) continue; 3807 3808 // Function-to-pointer conversion. 3809 if (!ParamWasReference && ParamType->isPointerType() && 3810 ArgType->isFunctionType()) 3811 ArgType = S.Context.getPointerType(ArgType); 3812 3813 // - If the argument is an overload set (not containing function 3814 // templates), trial argument deduction is attempted using each 3815 // of the members of the set. If deduction succeeds for only one 3816 // of the overload set members, that member is used as the 3817 // argument value for the deduction. If deduction succeeds for 3818 // more than one member of the overload set the parameter is 3819 // treated as a non-deduced context. 3820 3821 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 3822 // Type deduction is done independently for each P/A pair, and 3823 // the deduced template argument values are then combined. 3824 // So we do not reject deductions which were made elsewhere. 3825 SmallVector<DeducedTemplateArgument, 8> 3826 Deduced(TemplateParams->size()); 3827 TemplateDeductionInfo Info(Ovl->getNameLoc()); 3828 Sema::TemplateDeductionResult Result 3829 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 3830 ArgType, Info, Deduced, TDF); 3831 if (Result) continue; 3832 if (!Match.isNull()) 3833 return {}; 3834 Match = ArgType; 3835 } 3836 3837 return Match; 3838} 3839 3840/// Perform the adjustments to the parameter and argument types 3841/// described in C++ [temp.deduct.call]. 3842/// 3843/// \returns true if the caller should not attempt to perform any template 3844/// argument deduction based on this P/A pair because the argument is an 3845/// overloaded function set that could not be resolved. 3846static bool AdjustFunctionParmAndArgTypesForDeduction( 3847 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex, 3848 QualType &ParamType, QualType &ArgType, Expr *Arg, unsigned &TDF) { 3849 // C++0x [temp.deduct.call]p3: 3850 // If P is a cv-qualified type, the top level cv-qualifiers of P's type 3851 // are ignored for type deduction. 3852 if (ParamType.hasQualifiers()) 3853 ParamType = ParamType.getUnqualifiedType(); 3854 3855 // [...] If P is a reference type, the type referred to by P is 3856 // used for type deduction. 3857 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>(); 3858 if (ParamRefType) 3859 ParamType = ParamRefType->getPointeeType(); 3860 3861 // Overload sets usually make this parameter an undeduced context, 3862 // but there are sometimes special circumstances. Typically 3863 // involving a template-id-expr. 3864 if (ArgType == S.Context.OverloadTy) { 3865 ArgType = ResolveOverloadForDeduction(S, TemplateParams, 3866 Arg, ParamType, 3867 ParamRefType != nullptr); 3868 if (ArgType.isNull()) 3869 return true; 3870 } 3871 3872 if (ParamRefType) { 3873 // If the argument has incomplete array type, try to complete its type. 3874 if (ArgType->isIncompleteArrayType()) 3875 ArgType = S.getCompletedType(Arg); 3876 3877 // C++1z [temp.deduct.call]p3: 3878 // If P is a forwarding reference and the argument is an lvalue, the type 3879 // "lvalue reference to A" is used in place of A for type deduction. 3880 if (isForwardingReference(QualType(ParamRefType, 0), FirstInnerIndex) && 3881 Arg->isLValue()) { 3882 if (S.getLangOpts().OpenCL && !ArgType.hasAddressSpace()) 3883 ArgType = S.Context.getAddrSpaceQualType(ArgType, LangAS::opencl_generic); 3884 ArgType = S.Context.getLValueReferenceType(ArgType); 3885 } 3886 } else { 3887 // C++ [temp.deduct.call]p2: 3888 // If P is not a reference type: 3889 // - If A is an array type, the pointer type produced by the 3890 // array-to-pointer standard conversion (4.2) is used in place of 3891 // A for type deduction; otherwise, 3892 if (ArgType->isArrayType()) 3893 ArgType = S.Context.getArrayDecayedType(ArgType); 3894 // - If A is a function type, the pointer type produced by the 3895 // function-to-pointer standard conversion (4.3) is used in place 3896 // of A for type deduction; otherwise, 3897 else if (ArgType->isFunctionType()) 3898 ArgType = S.Context.getPointerType(ArgType); 3899 else { 3900 // - If A is a cv-qualified type, the top level cv-qualifiers of A's 3901 // type are ignored for type deduction. 3902 ArgType = ArgType.getUnqualifiedType(); 3903 } 3904 } 3905 3906 // C++0x [temp.deduct.call]p4: 3907 // In general, the deduction process attempts to find template argument 3908 // values that will make the deduced A identical to A (after the type A 3909 // is transformed as described above). [...] 3910 TDF = TDF_SkipNonDependent; 3911 3912 // - If the original P is a reference type, the deduced A (i.e., the 3913 // type referred to by the reference) can be more cv-qualified than 3914 // the transformed A. 3915 if (ParamRefType) 3916 TDF |= TDF_ParamWithReferenceType; 3917 // - The transformed A can be another pointer or pointer to member 3918 // type that can be converted to the deduced A via a qualification 3919 // conversion (4.4). 3920 if (ArgType->isPointerType() || ArgType->isMemberPointerType() || 3921 ArgType->isObjCObjectPointerType()) 3922 TDF |= TDF_IgnoreQualifiers; 3923 // - If P is a class and P has the form simple-template-id, then the 3924 // transformed A can be a derived class of the deduced A. Likewise, 3925 // if P is a pointer to a class of the form simple-template-id, the 3926 // transformed A can be a pointer to a derived class pointed to by 3927 // the deduced A. 3928 if (isSimpleTemplateIdType(ParamType) || 3929 (isa<PointerType>(ParamType) && 3930 isSimpleTemplateIdType( 3931 ParamType->castAs<PointerType>()->getPointeeType()))) 3932 TDF |= TDF_DerivedClass; 3933 3934 return false; 3935} 3936 3937static bool 3938hasDeducibleTemplateParameters(Sema &S, FunctionTemplateDecl *FunctionTemplate, 3939 QualType T); 3940 3941static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument( 3942 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex, 3943 QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info, 3944 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 3945 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs, 3946 bool DecomposedParam, unsigned ArgIdx, unsigned TDF); 3947 3948/// Attempt template argument deduction from an initializer list 3949/// deemed to be an argument in a function call. 3950static Sema::TemplateDeductionResult DeduceFromInitializerList( 3951 Sema &S, TemplateParameterList *TemplateParams, QualType AdjustedParamType, 3952 InitListExpr *ILE, TemplateDeductionInfo &Info, 3953 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 3954 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs, unsigned ArgIdx, 3955 unsigned TDF) { 3956 // C++ [temp.deduct.call]p1: (CWG 1591) 3957 // If removing references and cv-qualifiers from P gives 3958 // std::initializer_list<P0> or P0[N] for some P0 and N and the argument is 3959 // a non-empty initializer list, then deduction is performed instead for 3960 // each element of the initializer list, taking P0 as a function template 3961 // parameter type and the initializer element as its argument 3962 // 3963 // We've already removed references and cv-qualifiers here. 3964 if (!ILE->getNumInits()) 3965 return Sema::TDK_Success; 3966 3967 QualType ElTy; 3968 auto *ArrTy = S.Context.getAsArrayType(AdjustedParamType); 3969 if (ArrTy) 3970 ElTy = ArrTy->getElementType(); 3971 else if (!S.isStdInitializerList(AdjustedParamType, &ElTy)) { 3972 // Otherwise, an initializer list argument causes the parameter to be 3973 // considered a non-deduced context 3974 return Sema::TDK_Success; 3975 } 3976 3977 // Resolving a core issue: a braced-init-list containing any designators is 3978 // a non-deduced context. 3979 for (Expr *E : ILE->inits()) 3980 if (isa<DesignatedInitExpr>(E)) 3981 return Sema::TDK_Success; 3982 3983 // Deduction only needs to be done for dependent types. 3984 if (ElTy->isDependentType()) { 3985 for (Expr *E : ILE->inits()) { 3986 if (auto Result = DeduceTemplateArgumentsFromCallArgument( 3987 S, TemplateParams, 0, ElTy, E, Info, Deduced, OriginalCallArgs, true, 3988 ArgIdx, TDF)) 3989 return Result; 3990 } 3991 } 3992 3993 // in the P0[N] case, if N is a non-type template parameter, N is deduced 3994 // from the length of the initializer list. 3995 if (auto *DependentArrTy = dyn_cast_or_null<DependentSizedArrayType>(ArrTy)) { 3996 // Determine the array bound is something we can deduce. 3997 if (const NonTypeTemplateParmDecl *NTTP = 3998 getDeducedParameterFromExpr(Info, DependentArrTy->getSizeExpr())) { 3999 // We can perform template argument deduction for the given non-type 4000 // template parameter. 4001 // C++ [temp.deduct.type]p13: 4002 // The type of N in the type T[N] is std::size_t. 4003 QualType T = S.Context.getSizeType(); 4004 llvm::APInt Size(S.Context.getIntWidth(T), ILE->getNumInits()); 4005 if (auto Result = DeduceNonTypeTemplateArgument( 4006 S, TemplateParams, NTTP, llvm::APSInt(Size), T, 4007 /*ArrayBound=*/true, Info, Deduced)) 4008 return Result; 4009 } 4010 } 4011 4012 return Sema::TDK_Success; 4013} 4014 4015/// Perform template argument deduction per [temp.deduct.call] for a 4016/// single parameter / argument pair. 4017static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument( 4018 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex, 4019 QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info, 4020 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 4021 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs, 4022 bool DecomposedParam, unsigned ArgIdx, unsigned TDF) { 4023 QualType ArgType = Arg->getType(); 4024 QualType OrigParamType = ParamType; 4025 4026 // If P is a reference type [...] 4027 // If P is a cv-qualified type [...] 4028 if (AdjustFunctionParmAndArgTypesForDeduction( 4029 S, TemplateParams, FirstInnerIndex, ParamType, ArgType, Arg, TDF)) 4030 return Sema::TDK_Success; 4031 4032 // If [...] the argument is a non-empty initializer list [...] 4033 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) 4034 return DeduceFromInitializerList(S, TemplateParams, ParamType, ILE, Info, 4035 Deduced, OriginalCallArgs, ArgIdx, TDF); 4036 4037 // [...] the deduction process attempts to find template argument values 4038 // that will make the deduced A identical to A 4039 // 4040 // Keep track of the argument type and corresponding parameter index, 4041 // so we can check for compatibility between the deduced A and A. 4042 OriginalCallArgs.push_back( 4043 Sema::OriginalCallArg(OrigParamType, DecomposedParam, ArgIdx, ArgType)); 4044 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 4045 ArgType, Info, Deduced, TDF); 4046} 4047 4048/// Perform template argument deduction from a function call 4049/// (C++ [temp.deduct.call]). 4050/// 4051/// \param FunctionTemplate the function template for which we are performing 4052/// template argument deduction. 4053/// 4054/// \param ExplicitTemplateArgs the explicit template arguments provided 4055/// for this call. 4056/// 4057/// \param Args the function call arguments 4058/// 4059/// \param Specialization if template argument deduction was successful, 4060/// this will be set to the function template specialization produced by 4061/// template argument deduction. 4062/// 4063/// \param Info the argument will be updated to provide additional information 4064/// about template argument deduction. 4065/// 4066/// \param CheckNonDependent A callback to invoke to check conversions for 4067/// non-dependent parameters, between deduction and substitution, per DR1391. 4068/// If this returns true, substitution will be skipped and we return 4069/// TDK_NonDependentConversionFailure. The callback is passed the parameter 4070/// types (after substituting explicit template arguments). 4071/// 4072/// \returns the result of template argument deduction. 4073Sema::TemplateDeductionResult Sema::DeduceTemplateArguments( 4074 FunctionTemplateDecl *FunctionTemplate, 4075 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args, 4076 FunctionDecl *&Specialization, TemplateDeductionInfo &Info, 4077 bool PartialOverloading, 4078 llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent) { 4079 if (FunctionTemplate->isInvalidDecl()) 4080 return TDK_Invalid; 4081 4082 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 4083 unsigned NumParams = Function->getNumParams(); 4084 4085 unsigned FirstInnerIndex = getFirstInnerIndex(FunctionTemplate); 4086 4087 // C++ [temp.deduct.call]p1: 4088 // Template argument deduction is done by comparing each function template 4089 // parameter type (call it P) with the type of the corresponding argument 4090 // of the call (call it A) as described below. 4091 if (Args.size() < Function->getMinRequiredArguments() && !PartialOverloading) 4092 return TDK_TooFewArguments; 4093 else if (TooManyArguments(NumParams, Args.size(), PartialOverloading)) { 4094 const auto *Proto = Function->getType()->castAs<FunctionProtoType>(); 4095 if (Proto->isTemplateVariadic()) 4096 /* Do nothing */; 4097 else if (!Proto->isVariadic()) 4098 return TDK_TooManyArguments; 4099 } 4100 4101 // The types of the parameters from which we will perform template argument 4102 // deduction. 4103 LocalInstantiationScope InstScope(*this); 4104 TemplateParameterList *TemplateParams 4105 = FunctionTemplate->getTemplateParameters(); 4106 SmallVector<DeducedTemplateArgument, 4> Deduced; 4107 SmallVector<QualType, 8> ParamTypes; 4108 unsigned NumExplicitlySpecified = 0; 4109 if (ExplicitTemplateArgs) { 4110 TemplateDeductionResult Result; 4111 runWithSufficientStackSpace(Info.getLocation(), [&] { 4112 Result = SubstituteExplicitTemplateArguments( 4113 FunctionTemplate, *ExplicitTemplateArgs, Deduced, ParamTypes, nullptr, 4114 Info); 4115 }); 4116 if (Result) 4117 return Result; 4118 4119 NumExplicitlySpecified = Deduced.size(); 4120 } else { 4121 // Just fill in the parameter types from the function declaration. 4122 for (unsigned I = 0; I != NumParams; ++I) 4123 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 4124 } 4125 4126 SmallVector<OriginalCallArg, 8> OriginalCallArgs; 4127 4128 // Deduce an argument of type ParamType from an expression with index ArgIdx. 4129 auto DeduceCallArgument = [&](QualType ParamType, unsigned ArgIdx) { 4130 // C++ [demp.deduct.call]p1: (DR1391) 4131 // Template argument deduction is done by comparing each function template 4132 // parameter that contains template-parameters that participate in 4133 // template argument deduction ... 4134 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 4135 return Sema::TDK_Success; 4136 4137 // ... with the type of the corresponding argument 4138 return DeduceTemplateArgumentsFromCallArgument( 4139 *this, TemplateParams, FirstInnerIndex, ParamType, Args[ArgIdx], Info, Deduced, 4140 OriginalCallArgs, /*Decomposed*/false, ArgIdx, /*TDF*/ 0); 4141 }; 4142 4143 // Deduce template arguments from the function parameters. 4144 Deduced.resize(TemplateParams->size()); 4145 SmallVector<QualType, 8> ParamTypesForArgChecking; 4146 for (unsigned ParamIdx = 0, NumParamTypes = ParamTypes.size(), ArgIdx = 0; 4147 ParamIdx != NumParamTypes; ++ParamIdx) { 4148 QualType ParamType = ParamTypes[ParamIdx]; 4149 4150 const PackExpansionType *ParamExpansion = 4151 dyn_cast<PackExpansionType>(ParamType); 4152 if (!ParamExpansion) { 4153 // Simple case: matching a function parameter to a function argument. 4154 if (ArgIdx >= Args.size()) 4155 break; 4156 4157 ParamTypesForArgChecking.push_back(ParamType); 4158 if (auto Result = DeduceCallArgument(ParamType, ArgIdx++)) 4159 return Result; 4160 4161 continue; 4162 } 4163 4164 QualType ParamPattern = ParamExpansion->getPattern(); 4165 PackDeductionScope PackScope(*this, TemplateParams, Deduced, Info, 4166 ParamPattern); 4167 4168 // C++0x [temp.deduct.call]p1: 4169 // For a function parameter pack that occurs at the end of the 4170 // parameter-declaration-list, the type A of each remaining argument of 4171 // the call is compared with the type P of the declarator-id of the 4172 // function parameter pack. Each comparison deduces template arguments 4173 // for subsequent positions in the template parameter packs expanded by 4174 // the function parameter pack. When a function parameter pack appears 4175 // in a non-deduced context [not at the end of the list], the type of 4176 // that parameter pack is never deduced. 4177 // 4178 // FIXME: The above rule allows the size of the parameter pack to change 4179 // after we skip it (in the non-deduced case). That makes no sense, so 4180 // we instead notionally deduce the pack against N arguments, where N is 4181 // the length of the explicitly-specified pack if it's expanded by the 4182 // parameter pack and 0 otherwise, and we treat each deduction as a 4183 // non-deduced context. 4184 if (ParamIdx + 1 == NumParamTypes || PackScope.hasFixedArity()) { 4185 for (; ArgIdx < Args.size() && PackScope.hasNextElement(); 4186 PackScope.nextPackElement(), ++ArgIdx) { 4187 ParamTypesForArgChecking.push_back(ParamPattern); 4188 if (auto Result = DeduceCallArgument(ParamPattern, ArgIdx)) 4189 return Result; 4190 } 4191 } else { 4192 // If the parameter type contains an explicitly-specified pack that we 4193 // could not expand, skip the number of parameters notionally created 4194 // by the expansion. 4195 Optional<unsigned> NumExpansions = ParamExpansion->getNumExpansions(); 4196 if (NumExpansions && !PackScope.isPartiallyExpanded()) { 4197 for (unsigned I = 0; I != *NumExpansions && ArgIdx < Args.size(); 4198 ++I, ++ArgIdx) { 4199 ParamTypesForArgChecking.push_back(ParamPattern); 4200 // FIXME: Should we add OriginalCallArgs for these? What if the 4201 // corresponding argument is a list? 4202 PackScope.nextPackElement(); 4203 } 4204 } 4205 } 4206 4207 // Build argument packs for each of the parameter packs expanded by this 4208 // pack expansion. 4209 if (auto Result = PackScope.finish()) 4210 return Result; 4211 } 4212 4213 // Capture the context in which the function call is made. This is the context 4214 // that is needed when the accessibility of template arguments is checked. 4215 DeclContext *CallingCtx = CurContext; 4216 4217 TemplateDeductionResult Result; 4218 runWithSufficientStackSpace(Info.getLocation(), [&] { 4219 Result = FinishTemplateArgumentDeduction( 4220 FunctionTemplate, Deduced, NumExplicitlySpecified, Specialization, Info, 4221 &OriginalCallArgs, PartialOverloading, [&, CallingCtx]() { 4222 ContextRAII SavedContext(*this, CallingCtx); 4223 return CheckNonDependent(ParamTypesForArgChecking); 4224 }); 4225 }); 4226 return Result; 4227} 4228 4229QualType Sema::adjustCCAndNoReturn(QualType ArgFunctionType, 4230 QualType FunctionType, 4231 bool AdjustExceptionSpec) { 4232 if (ArgFunctionType.isNull()) 4233 return ArgFunctionType; 4234 4235 const auto *FunctionTypeP = FunctionType->castAs<FunctionProtoType>(); 4236 const auto *ArgFunctionTypeP = ArgFunctionType->castAs<FunctionProtoType>(); 4237 FunctionProtoType::ExtProtoInfo EPI = ArgFunctionTypeP->getExtProtoInfo(); 4238 bool Rebuild = false; 4239 4240 CallingConv CC = FunctionTypeP->getCallConv(); 4241 if (EPI.ExtInfo.getCC() != CC) { 4242 EPI.ExtInfo = EPI.ExtInfo.withCallingConv(CC); 4243 Rebuild = true; 4244 } 4245 4246 bool NoReturn = FunctionTypeP->getNoReturnAttr(); 4247 if (EPI.ExtInfo.getNoReturn() != NoReturn) { 4248 EPI.ExtInfo = EPI.ExtInfo.withNoReturn(NoReturn); 4249 Rebuild = true; 4250 } 4251 4252 if (AdjustExceptionSpec && (FunctionTypeP->hasExceptionSpec() || 4253 ArgFunctionTypeP->hasExceptionSpec())) { 4254 EPI.ExceptionSpec = FunctionTypeP->getExtProtoInfo().ExceptionSpec; 4255 Rebuild = true; 4256 } 4257 4258 if (!Rebuild) 4259 return ArgFunctionType; 4260 4261 return Context.getFunctionType(ArgFunctionTypeP->getReturnType(), 4262 ArgFunctionTypeP->getParamTypes(), EPI); 4263} 4264 4265/// Deduce template arguments when taking the address of a function 4266/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 4267/// a template. 4268/// 4269/// \param FunctionTemplate the function template for which we are performing 4270/// template argument deduction. 4271/// 4272/// \param ExplicitTemplateArgs the explicitly-specified template 4273/// arguments. 4274/// 4275/// \param ArgFunctionType the function type that will be used as the 4276/// "argument" type (A) when performing template argument deduction from the 4277/// function template's function type. This type may be NULL, if there is no 4278/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 4279/// 4280/// \param Specialization if template argument deduction was successful, 4281/// this will be set to the function template specialization produced by 4282/// template argument deduction. 4283/// 4284/// \param Info the argument will be updated to provide additional information 4285/// about template argument deduction. 4286/// 4287/// \param IsAddressOfFunction If \c true, we are deducing as part of taking 4288/// the address of a function template per [temp.deduct.funcaddr] and 4289/// [over.over]. If \c false, we are looking up a function template 4290/// specialization based on its signature, per [temp.deduct.decl]. 4291/// 4292/// \returns the result of template argument deduction. 4293Sema::TemplateDeductionResult Sema::DeduceTemplateArguments( 4294 FunctionTemplateDecl *FunctionTemplate, 4295 TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType, 4296 FunctionDecl *&Specialization, TemplateDeductionInfo &Info, 4297 bool IsAddressOfFunction) { 4298 if (FunctionTemplate->isInvalidDecl()) 4299 return TDK_Invalid; 4300 4301 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 4302 TemplateParameterList *TemplateParams 4303 = FunctionTemplate->getTemplateParameters(); 4304 QualType FunctionType = Function->getType(); 4305 4306 // Substitute any explicit template arguments. 4307 LocalInstantiationScope InstScope(*this); 4308 SmallVector<DeducedTemplateArgument, 4> Deduced; 4309 unsigned NumExplicitlySpecified = 0; 4310 SmallVector<QualType, 4> ParamTypes; 4311 if (ExplicitTemplateArgs) { 4312 TemplateDeductionResult Result; 4313 runWithSufficientStackSpace(Info.getLocation(), [&] { 4314 Result = SubstituteExplicitTemplateArguments( 4315 FunctionTemplate, *ExplicitTemplateArgs, Deduced, ParamTypes, 4316 &FunctionType, Info); 4317 }); 4318 if (Result) 4319 return Result; 4320 4321 NumExplicitlySpecified = Deduced.size(); 4322 } 4323 4324 // When taking the address of a function, we require convertibility of 4325 // the resulting function type. Otherwise, we allow arbitrary mismatches 4326 // of calling convention and noreturn. 4327 if (!IsAddressOfFunction) 4328 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, FunctionType, 4329 /*AdjustExceptionSpec*/false); 4330 4331 // Unevaluated SFINAE context. 4332 EnterExpressionEvaluationContext Unevaluated( 4333 *this, Sema::ExpressionEvaluationContext::Unevaluated); 4334 SFINAETrap Trap(*this); 4335 4336 Deduced.resize(TemplateParams->size()); 4337 4338 // If the function has a deduced return type, substitute it for a dependent 4339 // type so that we treat it as a non-deduced context in what follows. If we 4340 // are looking up by signature, the signature type should also have a deduced 4341 // return type, which we instead expect to exactly match. 4342 bool HasDeducedReturnType = false; 4343 if (getLangOpts().CPlusPlus14 && IsAddressOfFunction && 4344 Function->getReturnType()->getContainedAutoType()) { 4345 FunctionType = SubstAutoType(FunctionType, Context.DependentTy); 4346 HasDeducedReturnType = true; 4347 } 4348 4349 if (!ArgFunctionType.isNull()) { 4350 unsigned TDF = 4351 TDF_TopLevelParameterTypeList | TDF_AllowCompatibleFunctionType; 4352 // Deduce template arguments from the function type. 4353 if (TemplateDeductionResult Result 4354 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 4355 FunctionType, ArgFunctionType, 4356 Info, Deduced, TDF)) 4357 return Result; 4358 } 4359 4360 TemplateDeductionResult Result; 4361 runWithSufficientStackSpace(Info.getLocation(), [&] { 4362 Result = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 4363 NumExplicitlySpecified, 4364 Specialization, Info); 4365 }); 4366 if (Result) 4367 return Result; 4368 4369 // If the function has a deduced return type, deduce it now, so we can check 4370 // that the deduced function type matches the requested type. 4371 if (HasDeducedReturnType && 4372 Specialization->getReturnType()->isUndeducedType() && 4373 DeduceReturnType(Specialization, Info.getLocation(), false)) 4374 return TDK_MiscellaneousDeductionFailure; 4375 4376 // If the function has a dependent exception specification, resolve it now, 4377 // so we can check that the exception specification matches. 4378 auto *SpecializationFPT = 4379 Specialization->getType()->castAs<FunctionProtoType>(); 4380 if (getLangOpts().CPlusPlus17 && 4381 isUnresolvedExceptionSpec(SpecializationFPT->getExceptionSpecType()) && 4382 !ResolveExceptionSpec(Info.getLocation(), SpecializationFPT)) 4383 return TDK_MiscellaneousDeductionFailure; 4384 4385 // Adjust the exception specification of the argument to match the 4386 // substituted and resolved type we just formed. (Calling convention and 4387 // noreturn can't be dependent, so we don't actually need this for them 4388 // right now.) 4389 QualType SpecializationType = Specialization->getType(); 4390 if (!IsAddressOfFunction) 4391 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, SpecializationType, 4392 /*AdjustExceptionSpec*/true); 4393 4394 // If the requested function type does not match the actual type of the 4395 // specialization with respect to arguments of compatible pointer to function 4396 // types, template argument deduction fails. 4397 if (!ArgFunctionType.isNull()) { 4398 if (IsAddressOfFunction && 4399 !isSameOrCompatibleFunctionType( 4400 Context.getCanonicalType(SpecializationType), 4401 Context.getCanonicalType(ArgFunctionType))) 4402 return TDK_MiscellaneousDeductionFailure; 4403 4404 if (!IsAddressOfFunction && 4405 !Context.hasSameType(SpecializationType, ArgFunctionType)) 4406 return TDK_MiscellaneousDeductionFailure; 4407 } 4408 4409 return TDK_Success; 4410} 4411 4412/// Deduce template arguments for a templated conversion 4413/// function (C++ [temp.deduct.conv]) and, if successful, produce a 4414/// conversion function template specialization. 4415Sema::TemplateDeductionResult 4416Sema::DeduceTemplateArguments(FunctionTemplateDecl *ConversionTemplate, 4417 QualType ToType, 4418 CXXConversionDecl *&Specialization, 4419 TemplateDeductionInfo &Info) { 4420 if (ConversionTemplate->isInvalidDecl()) 4421 return TDK_Invalid; 4422 4423 CXXConversionDecl *ConversionGeneric 4424 = cast<CXXConversionDecl>(ConversionTemplate->getTemplatedDecl()); 4425 4426 QualType FromType = ConversionGeneric->getConversionType(); 4427 4428 // Canonicalize the types for deduction. 4429 QualType P = Context.getCanonicalType(FromType); 4430 QualType A = Context.getCanonicalType(ToType); 4431 4432 // C++0x [temp.deduct.conv]p2: 4433 // If P is a reference type, the type referred to by P is used for 4434 // type deduction. 4435 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 4436 P = PRef->getPointeeType(); 4437 4438 // C++0x [temp.deduct.conv]p4: 4439 // [...] If A is a reference type, the type referred to by A is used 4440 // for type deduction. 4441 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) { 4442 A = ARef->getPointeeType(); 4443 // We work around a defect in the standard here: cv-qualifiers are also 4444 // removed from P and A in this case, unless P was a reference type. This 4445 // seems to mostly match what other compilers are doing. 4446 if (!FromType->getAs<ReferenceType>()) { 4447 A = A.getUnqualifiedType(); 4448 P = P.getUnqualifiedType(); 4449 } 4450 4451 // C++ [temp.deduct.conv]p3: 4452 // 4453 // If A is not a reference type: 4454 } else { 4455 assert(!A->isReferenceType() && "Reference types were handled above")((void)0); 4456 4457 // - If P is an array type, the pointer type produced by the 4458 // array-to-pointer standard conversion (4.2) is used in place 4459 // of P for type deduction; otherwise, 4460 if (P->isArrayType()) 4461 P = Context.getArrayDecayedType(P); 4462 // - If P is a function type, the pointer type produced by the 4463 // function-to-pointer standard conversion (4.3) is used in 4464 // place of P for type deduction; otherwise, 4465 else if (P->isFunctionType()) 4466 P = Context.getPointerType(P); 4467 // - If P is a cv-qualified type, the top level cv-qualifiers of 4468 // P's type are ignored for type deduction. 4469 else 4470 P = P.getUnqualifiedType(); 4471 4472 // C++0x [temp.deduct.conv]p4: 4473 // If A is a cv-qualified type, the top level cv-qualifiers of A's 4474 // type are ignored for type deduction. If A is a reference type, the type 4475 // referred to by A is used for type deduction. 4476 A = A.getUnqualifiedType(); 4477 } 4478 4479 // Unevaluated SFINAE context. 4480 EnterExpressionEvaluationContext Unevaluated( 4481 *this, Sema::ExpressionEvaluationContext::Unevaluated); 4482 SFINAETrap Trap(*this); 4483 4484 // C++ [temp.deduct.conv]p1: 4485 // Template argument deduction is done by comparing the return 4486 // type of the template conversion function (call it P) with the 4487 // type that is required as the result of the conversion (call it 4488 // A) as described in 14.8.2.4. 4489 TemplateParameterList *TemplateParams 4490 = ConversionTemplate->getTemplateParameters(); 4491 SmallVector<DeducedTemplateArgument, 4> Deduced; 4492 Deduced.resize(TemplateParams->size()); 4493 4494 // C++0x [temp.deduct.conv]p4: 4495 // In general, the deduction process attempts to find template 4496 // argument values that will make the deduced A identical to 4497 // A. However, there are two cases that allow a difference: 4498 unsigned TDF = 0; 4499 // - If the original A is a reference type, A can be more 4500 // cv-qualified than the deduced A (i.e., the type referred to 4501 // by the reference) 4502 if (ToType->isReferenceType()) 4503 TDF |= TDF_ArgWithReferenceType; 4504 // - The deduced A can be another pointer or pointer to member 4505 // type that can be converted to A via a qualification 4506 // conversion. 4507 // 4508 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 4509 // both P and A are pointers or member pointers. In this case, we 4510 // just ignore cv-qualifiers completely). 4511 if ((P->isPointerType() && A->isPointerType()) || 4512 (P->isMemberPointerType() && A->isMemberPointerType())) 4513 TDF |= TDF_IgnoreQualifiers; 4514 if (TemplateDeductionResult Result 4515 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 4516 P, A, Info, Deduced, TDF)) 4517 return Result; 4518 4519 // Create an Instantiation Scope for finalizing the operator. 4520 LocalInstantiationScope InstScope(*this); 4521 // Finish template argument deduction. 4522 FunctionDecl *ConversionSpecialized = nullptr; 4523 TemplateDeductionResult Result; 4524 runWithSufficientStackSpace(Info.getLocation(), [&] { 4525 Result = FinishTemplateArgumentDeduction(ConversionTemplate, Deduced, 0, 4526 ConversionSpecialized, Info); 4527 }); 4528 Specialization = cast_or_null<CXXConversionDecl>(ConversionSpecialized); 4529 return Result; 4530} 4531 4532/// Deduce template arguments for a function template when there is 4533/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 4534/// 4535/// \param FunctionTemplate the function template for which we are performing 4536/// template argument deduction. 4537/// 4538/// \param ExplicitTemplateArgs the explicitly-specified template 4539/// arguments. 4540/// 4541/// \param Specialization if template argument deduction was successful, 4542/// this will be set to the function template specialization produced by 4543/// template argument deduction. 4544/// 4545/// \param Info the argument will be updated to provide additional information 4546/// about template argument deduction. 4547/// 4548/// \param IsAddressOfFunction If \c true, we are deducing as part of taking 4549/// the address of a function template in a context where we do not have a 4550/// target type, per [over.over]. If \c false, we are looking up a function 4551/// template specialization based on its signature, which only happens when 4552/// deducing a function parameter type from an argument that is a template-id 4553/// naming a function template specialization. 4554/// 4555/// \returns the result of template argument deduction. 4556Sema::TemplateDeductionResult Sema::DeduceTemplateArguments( 4557 FunctionTemplateDecl *FunctionTemplate, 4558 TemplateArgumentListInfo *ExplicitTemplateArgs, 4559 FunctionDecl *&Specialization, TemplateDeductionInfo &Info, 4560 bool IsAddressOfFunction) { 4561 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 4562 QualType(), Specialization, Info, 4563 IsAddressOfFunction); 4564} 4565 4566namespace { 4567 struct DependentAuto { bool IsPack; }; 4568 4569 /// Substitute the 'auto' specifier or deduced template specialization type 4570 /// specifier within a type for a given replacement type. 4571 class SubstituteDeducedTypeTransform : 4572 public TreeTransform<SubstituteDeducedTypeTransform> { 4573 QualType Replacement; 4574 bool ReplacementIsPack; 4575 bool UseTypeSugar; 4576 4577 public: 4578 SubstituteDeducedTypeTransform(Sema &SemaRef, DependentAuto DA) 4579 : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef), Replacement(), 4580 ReplacementIsPack(DA.IsPack), UseTypeSugar(true) {} 4581 4582 SubstituteDeducedTypeTransform(Sema &SemaRef, QualType Replacement, 4583 bool UseTypeSugar = true) 4584 : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef), 4585 Replacement(Replacement), ReplacementIsPack(false), 4586 UseTypeSugar(UseTypeSugar) {} 4587 4588 QualType TransformDesugared(TypeLocBuilder &TLB, DeducedTypeLoc TL) { 4589 assert(isa<TemplateTypeParmType>(Replacement) &&((void)0) 4590 "unexpected unsugared replacement kind")((void)0); 4591 QualType Result = Replacement; 4592 TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result); 4593 NewTL.setNameLoc(TL.getNameLoc()); 4594 return Result; 4595 } 4596 4597 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) { 4598 // If we're building the type pattern to deduce against, don't wrap the 4599 // substituted type in an AutoType. Certain template deduction rules 4600 // apply only when a template type parameter appears directly (and not if 4601 // the parameter is found through desugaring). For instance: 4602 // auto &&lref = lvalue; 4603 // must transform into "rvalue reference to T" not "rvalue reference to 4604 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply. 4605 // 4606 // FIXME: Is this still necessary? 4607 if (!UseTypeSugar) 4608 return TransformDesugared(TLB, TL); 4609 4610 QualType Result = SemaRef.Context.getAutoType( 4611 Replacement, TL.getTypePtr()->getKeyword(), Replacement.isNull(), 4612 ReplacementIsPack, TL.getTypePtr()->getTypeConstraintConcept(), 4613 TL.getTypePtr()->getTypeConstraintArguments()); 4614 auto NewTL = TLB.push<AutoTypeLoc>(Result); 4615 NewTL.copy(TL); 4616 return Result; 4617 } 4618 4619 QualType TransformDeducedTemplateSpecializationType( 4620 TypeLocBuilder &TLB, DeducedTemplateSpecializationTypeLoc TL) { 4621 if (!UseTypeSugar) 4622 return TransformDesugared(TLB, TL); 4623 4624 QualType Result = SemaRef.Context.getDeducedTemplateSpecializationType( 4625 TL.getTypePtr()->getTemplateName(), 4626 Replacement, Replacement.isNull()); 4627 auto NewTL = TLB.push<DeducedTemplateSpecializationTypeLoc>(Result); 4628 NewTL.setNameLoc(TL.getNameLoc()); 4629 return Result; 4630 } 4631 4632 ExprResult TransformLambdaExpr(LambdaExpr *E) { 4633 // Lambdas never need to be transformed. 4634 return E; 4635 } 4636 4637 QualType Apply(TypeLoc TL) { 4638 // Create some scratch storage for the transformed type locations. 4639 // FIXME: We're just going to throw this information away. Don't build it. 4640 TypeLocBuilder TLB; 4641 TLB.reserve(TL.getFullDataSize()); 4642 return TransformType(TLB, TL); 4643 } 4644 }; 4645 4646} // namespace 4647 4648Sema::DeduceAutoResult 4649Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, QualType &Result, 4650 Optional<unsigned> DependentDeductionDepth, 4651 bool IgnoreConstraints) { 4652 return DeduceAutoType(Type->getTypeLoc(), Init, Result, 4653 DependentDeductionDepth, IgnoreConstraints); 4654} 4655 4656/// Attempt to produce an informative diagostic explaining why auto deduction 4657/// failed. 4658/// \return \c true if diagnosed, \c false if not. 4659static bool diagnoseAutoDeductionFailure(Sema &S, 4660 Sema::TemplateDeductionResult TDK, 4661 TemplateDeductionInfo &Info, 4662 ArrayRef<SourceRange> Ranges) { 4663 switch (TDK) { 4664 case Sema::TDK_Inconsistent: { 4665 // Inconsistent deduction means we were deducing from an initializer list. 4666 auto D = S.Diag(Info.getLocation(), diag::err_auto_inconsistent_deduction); 4667 D << Info.FirstArg << Info.SecondArg; 4668 for (auto R : Ranges) 4669 D << R; 4670 return true; 4671 } 4672 4673 // FIXME: Are there other cases for which a custom diagnostic is more useful 4674 // than the basic "types don't match" diagnostic? 4675 4676 default: 4677 return false; 4678 } 4679} 4680 4681static Sema::DeduceAutoResult 4682CheckDeducedPlaceholderConstraints(Sema &S, const AutoType &Type, 4683 AutoTypeLoc TypeLoc, QualType Deduced) { 4684 ConstraintSatisfaction Satisfaction; 4685 ConceptDecl *Concept = Type.getTypeConstraintConcept(); 4686 TemplateArgumentListInfo TemplateArgs(TypeLoc.getLAngleLoc(), 4687 TypeLoc.getRAngleLoc()); 4688 TemplateArgs.addArgument( 4689 TemplateArgumentLoc(TemplateArgument(Deduced), 4690 S.Context.getTrivialTypeSourceInfo( 4691 Deduced, TypeLoc.getNameLoc()))); 4692 for (unsigned I = 0, C = TypeLoc.getNumArgs(); I != C; ++I) 4693 TemplateArgs.addArgument(TypeLoc.getArgLoc(I)); 4694 4695 llvm::SmallVector<TemplateArgument, 4> Converted; 4696 if (S.CheckTemplateArgumentList(Concept, SourceLocation(), TemplateArgs, 4697 /*PartialTemplateArgs=*/false, Converted)) 4698 return Sema::DAR_FailedAlreadyDiagnosed; 4699 if (S.CheckConstraintSatisfaction(Concept, {Concept->getConstraintExpr()}, 4700 Converted, TypeLoc.getLocalSourceRange(), 4701 Satisfaction)) 4702 return Sema::DAR_FailedAlreadyDiagnosed; 4703 if (!Satisfaction.IsSatisfied) { 4704 std::string Buf; 4705 llvm::raw_string_ostream OS(Buf); 4706 OS << "'" << Concept->getName(); 4707 if (TypeLoc.hasExplicitTemplateArgs()) { 4708 printTemplateArgumentList( 4709 OS, Type.getTypeConstraintArguments(), S.getPrintingPolicy(), 4710 Type.getTypeConstraintConcept()->getTemplateParameters()); 4711 } 4712 OS << "'"; 4713 OS.flush(); 4714 S.Diag(TypeLoc.getConceptNameLoc(), 4715 diag::err_placeholder_constraints_not_satisfied) 4716 << Deduced << Buf << TypeLoc.getLocalSourceRange(); 4717 S.DiagnoseUnsatisfiedConstraint(Satisfaction); 4718 return Sema::DAR_FailedAlreadyDiagnosed; 4719 } 4720 return Sema::DAR_Succeeded; 4721} 4722 4723/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6) 4724/// 4725/// Note that this is done even if the initializer is dependent. (This is 4726/// necessary to support partial ordering of templates using 'auto'.) 4727/// A dependent type will be produced when deducing from a dependent type. 4728/// 4729/// \param Type the type pattern using the auto type-specifier. 4730/// \param Init the initializer for the variable whose type is to be deduced. 4731/// \param Result if type deduction was successful, this will be set to the 4732/// deduced type. 4733/// \param DependentDeductionDepth Set if we should permit deduction in 4734/// dependent cases. This is necessary for template partial ordering with 4735/// 'auto' template parameters. The value specified is the template 4736/// parameter depth at which we should perform 'auto' deduction. 4737/// \param IgnoreConstraints Set if we should not fail if the deduced type does 4738/// not satisfy the type-constraint in the auto type. 4739Sema::DeduceAutoResult 4740Sema::DeduceAutoType(TypeLoc Type, Expr *&Init, QualType &Result, 4741 Optional<unsigned> DependentDeductionDepth, 4742 bool IgnoreConstraints) { 4743 if (Init->containsErrors()) 4744 return DAR_FailedAlreadyDiagnosed; 4745 if (Init->getType()->isNonOverloadPlaceholderType()) { 4746 ExprResult NonPlaceholder = CheckPlaceholderExpr(Init); 4747 if (NonPlaceholder.isInvalid()) 4748 return DAR_FailedAlreadyDiagnosed; 4749 Init = NonPlaceholder.get(); 4750 } 4751 4752 DependentAuto DependentResult = { 4753 /*.IsPack = */ (bool)Type.getAs<PackExpansionTypeLoc>()}; 4754 4755 if (!DependentDeductionDepth && 4756 (Type.getType()->isDependentType() || Init->isTypeDependent() || 4757 Init->containsUnexpandedParameterPack())) { 4758 Result = SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type); 4759 assert(!Result.isNull() && "substituting DependentTy can't fail")((void)0); 4760 return DAR_Succeeded; 4761 } 4762 4763 // Find the depth of template parameter to synthesize. 4764 unsigned Depth = DependentDeductionDepth.getValueOr(0); 4765 4766 // If this is a 'decltype(auto)' specifier, do the decltype dance. 4767 // Since 'decltype(auto)' can only occur at the top of the type, we 4768 // don't need to go digging for it. 4769 if (const AutoType *AT = Type.getType()->getAs<AutoType>()) { 4770 if (AT->isDecltypeAuto()) { 4771 if (isa<InitListExpr>(Init)) { 4772 Diag(Init->getBeginLoc(), diag::err_decltype_auto_initializer_list); 4773 return DAR_FailedAlreadyDiagnosed; 4774 } 4775 4776 ExprResult ER = CheckPlaceholderExpr(Init); 4777 if (ER.isInvalid()) 4778 return DAR_FailedAlreadyDiagnosed; 4779 Init = ER.get(); 4780 QualType Deduced = BuildDecltypeType(Init, Init->getBeginLoc(), false); 4781 if (Deduced.isNull()) 4782 return DAR_FailedAlreadyDiagnosed; 4783 // FIXME: Support a non-canonical deduced type for 'auto'. 4784 Deduced = Context.getCanonicalType(Deduced); 4785 if (AT->isConstrained() && !IgnoreConstraints) { 4786 auto ConstraintsResult = 4787 CheckDeducedPlaceholderConstraints(*this, *AT, 4788 Type.getContainedAutoTypeLoc(), 4789 Deduced); 4790 if (ConstraintsResult != DAR_Succeeded) 4791 return ConstraintsResult; 4792 } 4793 Result = SubstituteDeducedTypeTransform(*this, Deduced).Apply(Type); 4794 if (Result.isNull()) 4795 return DAR_FailedAlreadyDiagnosed; 4796 return DAR_Succeeded; 4797 } else if (!getLangOpts().CPlusPlus) { 4798 if (isa<InitListExpr>(Init)) { 4799 Diag(Init->getBeginLoc(), diag::err_auto_init_list_from_c); 4800 return DAR_FailedAlreadyDiagnosed; 4801 } 4802 } 4803 } 4804 4805 SourceLocation Loc = Init->getExprLoc(); 4806 4807 LocalInstantiationScope InstScope(*this); 4808 4809 // Build template<class TemplParam> void Func(FuncParam); 4810 TemplateTypeParmDecl *TemplParam = TemplateTypeParmDecl::Create( 4811 Context, nullptr, SourceLocation(), Loc, Depth, 0, nullptr, false, false, 4812 false); 4813 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0); 4814 NamedDecl *TemplParamPtr = TemplParam; 4815 FixedSizeTemplateParameterListStorage<1, false> TemplateParamsSt( 4816 Context, Loc, Loc, TemplParamPtr, Loc, nullptr); 4817 4818 QualType FuncParam = 4819 SubstituteDeducedTypeTransform(*this, TemplArg, /*UseTypeSugar*/false) 4820 .Apply(Type); 4821 assert(!FuncParam.isNull() &&((void)0) 4822 "substituting template parameter for 'auto' failed")((void)0); 4823 4824 // Deduce type of TemplParam in Func(Init) 4825 SmallVector<DeducedTemplateArgument, 1> Deduced; 4826 Deduced.resize(1); 4827 4828 TemplateDeductionInfo Info(Loc, Depth); 4829 4830 // If deduction failed, don't diagnose if the initializer is dependent; it 4831 // might acquire a matching type in the instantiation. 4832 auto DeductionFailed = [&](TemplateDeductionResult TDK, 4833 ArrayRef<SourceRange> Ranges) -> DeduceAutoResult { 4834 if (Init->isTypeDependent()) { 4835 Result = 4836 SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type); 4837 assert(!Result.isNull() && "substituting DependentTy can't fail")((void)0); 4838 return DAR_Succeeded; 4839 } 4840 if (diagnoseAutoDeductionFailure(*this, TDK, Info, Ranges)) 4841 return DAR_FailedAlreadyDiagnosed; 4842 return DAR_Failed; 4843 }; 4844 4845 SmallVector<OriginalCallArg, 4> OriginalCallArgs; 4846 4847 InitListExpr *InitList = dyn_cast<InitListExpr>(Init); 4848 if (InitList) { 4849 // Notionally, we substitute std::initializer_list<T> for 'auto' and deduce 4850 // against that. Such deduction only succeeds if removing cv-qualifiers and 4851 // references results in std::initializer_list<T>. 4852 if (!Type.getType().getNonReferenceType()->getAs<AutoType>()) 4853 return DAR_Failed; 4854 4855 // Resolving a core issue: a braced-init-list containing any designators is 4856 // a non-deduced context. 4857 for (Expr *E : InitList->inits()) 4858 if (isa<DesignatedInitExpr>(E)) 4859 return DAR_Failed; 4860 4861 SourceRange DeducedFromInitRange; 4862 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) { 4863 Expr *Init = InitList->getInit(i); 4864 4865 if (auto TDK = DeduceTemplateArgumentsFromCallArgument( 4866 *this, TemplateParamsSt.get(), 0, TemplArg, Init, 4867 Info, Deduced, OriginalCallArgs, /*Decomposed*/ true, 4868 /*ArgIdx*/ 0, /*TDF*/ 0)) 4869 return DeductionFailed(TDK, {DeducedFromInitRange, 4870 Init->getSourceRange()}); 4871 4872 if (DeducedFromInitRange.isInvalid() && 4873 Deduced[0].getKind() != TemplateArgument::Null) 4874 DeducedFromInitRange = Init->getSourceRange(); 4875 } 4876 } else { 4877 if (!getLangOpts().CPlusPlus && Init->refersToBitField()) { 4878 Diag(Loc, diag::err_auto_bitfield); 4879 return DAR_FailedAlreadyDiagnosed; 4880 } 4881 4882 if (auto TDK = DeduceTemplateArgumentsFromCallArgument( 4883 *this, TemplateParamsSt.get(), 0, FuncParam, Init, Info, Deduced, 4884 OriginalCallArgs, /*Decomposed*/ false, /*ArgIdx*/ 0, /*TDF*/ 0)) 4885 return DeductionFailed(TDK, {}); 4886 } 4887 4888 // Could be null if somehow 'auto' appears in a non-deduced context. 4889 if (Deduced[0].getKind() != TemplateArgument::Type) 4890 return DeductionFailed(TDK_Incomplete, {}); 4891 4892 QualType DeducedType = Deduced[0].getAsType(); 4893 4894 if (InitList) { 4895 DeducedType = BuildStdInitializerList(DeducedType, Loc); 4896 if (DeducedType.isNull()) 4897 return DAR_FailedAlreadyDiagnosed; 4898 } 4899 4900 if (const auto *AT = Type.getType()->getAs<AutoType>()) { 4901 if (AT->isConstrained() && !IgnoreConstraints) { 4902 auto ConstraintsResult = 4903 CheckDeducedPlaceholderConstraints(*this, *AT, 4904 Type.getContainedAutoTypeLoc(), 4905 DeducedType); 4906 if (ConstraintsResult != DAR_Succeeded) 4907 return ConstraintsResult; 4908 } 4909 } 4910 4911 Result = SubstituteDeducedTypeTransform(*this, DeducedType).Apply(Type); 4912 if (Result.isNull()) 4913 return DAR_FailedAlreadyDiagnosed; 4914 4915 // Check that the deduced argument type is compatible with the original 4916 // argument type per C++ [temp.deduct.call]p4. 4917 QualType DeducedA = InitList ? Deduced[0].getAsType() : Result; 4918 for (const OriginalCallArg &OriginalArg : OriginalCallArgs) { 4919 assert((bool)InitList == OriginalArg.DecomposedParam &&((void)0) 4920 "decomposed non-init-list in auto deduction?")((void)0); 4921 if (auto TDK = 4922 CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA)) { 4923 Result = QualType(); 4924 return DeductionFailed(TDK, {}); 4925 } 4926 } 4927 4928 return DAR_Succeeded; 4929} 4930 4931QualType Sema::SubstAutoType(QualType TypeWithAuto, 4932 QualType TypeToReplaceAuto) { 4933 if (TypeToReplaceAuto->isDependentType()) 4934 return SubstituteDeducedTypeTransform( 4935 *this, DependentAuto{ 4936 TypeToReplaceAuto->containsUnexpandedParameterPack()}) 4937 .TransformType(TypeWithAuto); 4938 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto) 4939 .TransformType(TypeWithAuto); 4940} 4941 4942TypeSourceInfo *Sema::SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto, 4943 QualType TypeToReplaceAuto) { 4944 if (TypeToReplaceAuto->isDependentType()) 4945 return SubstituteDeducedTypeTransform( 4946 *this, 4947 DependentAuto{ 4948 TypeToReplaceAuto->containsUnexpandedParameterPack()}) 4949 .TransformType(TypeWithAuto); 4950 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto) 4951 .TransformType(TypeWithAuto); 4952} 4953 4954QualType Sema::ReplaceAutoType(QualType TypeWithAuto, 4955 QualType TypeToReplaceAuto) { 4956 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto, 4957 /*UseTypeSugar*/ false) 4958 .TransformType(TypeWithAuto); 4959} 4960 4961TypeSourceInfo *Sema::ReplaceAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto, 4962 QualType TypeToReplaceAuto) { 4963 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto, 4964 /*UseTypeSugar*/ false) 4965 .TransformType(TypeWithAuto); 4966} 4967 4968void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) { 4969 if (isa<InitListExpr>(Init)) 4970 Diag(VDecl->getLocation(), 4971 VDecl->isInitCapture() 4972 ? diag::err_init_capture_deduction_failure_from_init_list 4973 : diag::err_auto_var_deduction_failure_from_init_list) 4974 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange(); 4975 else 4976 Diag(VDecl->getLocation(), 4977 VDecl->isInitCapture() ? diag::err_init_capture_deduction_failure 4978 : diag::err_auto_var_deduction_failure) 4979 << VDecl->getDeclName() << VDecl->getType() << Init->getType() 4980 << Init->getSourceRange(); 4981} 4982 4983bool Sema::DeduceReturnType(FunctionDecl *FD, SourceLocation Loc, 4984 bool Diagnose) { 4985 assert(FD->getReturnType()->isUndeducedType())((void)0); 4986 4987 // For a lambda's conversion operator, deduce any 'auto' or 'decltype(auto)' 4988 // within the return type from the call operator's type. 4989 if (isLambdaConversionOperator(FD)) { 4990 CXXRecordDecl *Lambda = cast<CXXMethodDecl>(FD)->getParent(); 4991 FunctionDecl *CallOp = Lambda->getLambdaCallOperator(); 4992 4993 // For a generic lambda, instantiate the call operator if needed. 4994 if (auto *Args = FD->getTemplateSpecializationArgs()) { 4995 CallOp = InstantiateFunctionDeclaration( 4996 CallOp->getDescribedFunctionTemplate(), Args, Loc); 4997 if (!CallOp || CallOp->isInvalidDecl()) 4998 return true; 4999 5000 // We might need to deduce the return type by instantiating the definition 5001 // of the operator() function. 5002 if (CallOp->getReturnType()->isUndeducedType()) { 5003 runWithSufficientStackSpace(Loc, [&] { 5004 InstantiateFunctionDefinition(Loc, CallOp); 5005 }); 5006 } 5007 } 5008 5009 if (CallOp->isInvalidDecl()) 5010 return true; 5011 assert(!CallOp->getReturnType()->isUndeducedType() &&((void)0) 5012 "failed to deduce lambda return type")((void)0); 5013 5014 // Build the new return type from scratch. 5015 CallingConv RetTyCC = FD->getReturnType() 5016 ->getPointeeType() 5017 ->castAs<FunctionType>() 5018 ->getCallConv(); 5019 QualType RetType = getLambdaConversionFunctionResultType( 5020 CallOp->getType()->castAs<FunctionProtoType>(), RetTyCC); 5021 if (FD->getReturnType()->getAs<PointerType>()) 5022 RetType = Context.getPointerType(RetType); 5023 else { 5024 assert(FD->getReturnType()->getAs<BlockPointerType>())((void)0); 5025 RetType = Context.getBlockPointerType(RetType); 5026 } 5027 Context.adjustDeducedFunctionResultType(FD, RetType); 5028 return false; 5029 } 5030 5031 if (FD->getTemplateInstantiationPattern()) { 5032 runWithSufficientStackSpace(Loc, [&] { 5033 InstantiateFunctionDefinition(Loc, FD); 5034 }); 5035 } 5036 5037 bool StillUndeduced = FD->getReturnType()->isUndeducedType(); 5038 if (StillUndeduced && Diagnose && !FD->isInvalidDecl()) { 5039 Diag(Loc, diag::err_auto_fn_used_before_defined) << FD; 5040 Diag(FD->getLocation(), diag::note_callee_decl) << FD; 5041 } 5042 5043 return StillUndeduced; 5044} 5045 5046/// If this is a non-static member function, 5047static void 5048AddImplicitObjectParameterType(ASTContext &Context, 5049 CXXMethodDecl *Method, 5050 SmallVectorImpl<QualType> &ArgTypes) { 5051 // C++11 [temp.func.order]p3: 5052 // [...] The new parameter is of type "reference to cv A," where cv are 5053 // the cv-qualifiers of the function template (if any) and A is 5054 // the class of which the function template is a member. 5055 // 5056 // The standard doesn't say explicitly, but we pick the appropriate kind of 5057 // reference type based on [over.match.funcs]p4. 5058 QualType ArgTy = Context.getTypeDeclType(Method->getParent()); 5059 ArgTy = Context.getQualifiedType(ArgTy, Method->getMethodQualifiers()); 5060 if (Method->getRefQualifier() == RQ_RValue) 5061 ArgTy = Context.getRValueReferenceType(ArgTy); 5062 else 5063 ArgTy = Context.getLValueReferenceType(ArgTy); 5064 ArgTypes.push_back(ArgTy); 5065} 5066 5067/// Determine whether the function template \p FT1 is at least as 5068/// specialized as \p FT2. 5069static bool isAtLeastAsSpecializedAs(Sema &S, 5070 SourceLocation Loc, 5071 FunctionTemplateDecl *FT1, 5072 FunctionTemplateDecl *FT2, 5073 TemplatePartialOrderingContext TPOC, 5074 unsigned NumCallArguments1, 5075 bool Reversed) { 5076 assert(!Reversed || TPOC == TPOC_Call)((void)0); 5077 5078 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 5079 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 5080 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 5081 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 5082 5083 assert(Proto1 && Proto2 && "Function templates must have prototypes")((void)0); 5084 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 5085 SmallVector<DeducedTemplateArgument, 4> Deduced; 5086 Deduced.resize(TemplateParams->size()); 5087 5088 // C++0x [temp.deduct.partial]p3: 5089 // The types used to determine the ordering depend on the context in which 5090 // the partial ordering is done: 5091 TemplateDeductionInfo Info(Loc); 5092 SmallVector<QualType, 4> Args2; 5093 switch (TPOC) { 5094 case TPOC_Call: { 5095 // - In the context of a function call, the function parameter types are 5096 // used. 5097 CXXMethodDecl *Method1 = dyn_cast<CXXMethodDecl>(FD1); 5098 CXXMethodDecl *Method2 = dyn_cast<CXXMethodDecl>(FD2); 5099 5100 // C++11 [temp.func.order]p3: 5101 // [...] If only one of the function templates is a non-static 5102 // member, that function template is considered to have a new 5103 // first parameter inserted in its function parameter list. The 5104 // new parameter is of type "reference to cv A," where cv are 5105 // the cv-qualifiers of the function template (if any) and A is 5106 // the class of which the function template is a member. 5107 // 5108 // Note that we interpret this to mean "if one of the function 5109 // templates is a non-static member and the other is a non-member"; 5110 // otherwise, the ordering rules for static functions against non-static 5111 // functions don't make any sense. 5112 // 5113 // C++98/03 doesn't have this provision but we've extended DR532 to cover 5114 // it as wording was broken prior to it. 5115 SmallVector<QualType, 4> Args1; 5116 5117 unsigned NumComparedArguments = NumCallArguments1; 5118 5119 if (!Method2 && Method1 && !Method1->isStatic()) { 5120 // Compare 'this' from Method1 against first parameter from Method2. 5121 AddImplicitObjectParameterType(S.Context, Method1, Args1); 5122 ++NumComparedArguments; 5123 } else if (!Method1 && Method2 && !Method2->isStatic()) { 5124 // Compare 'this' from Method2 against first parameter from Method1. 5125 AddImplicitObjectParameterType(S.Context, Method2, Args2); 5126 } else if (Method1 && Method2 && Reversed) { 5127 // Compare 'this' from Method1 against second parameter from Method2 5128 // and 'this' from Method2 against second parameter from Method1. 5129 AddImplicitObjectParameterType(S.Context, Method1, Args1); 5130 AddImplicitObjectParameterType(S.Context, Method2, Args2); 5131 ++NumComparedArguments; 5132 } 5133 5134 Args1.insert(Args1.end(), Proto1->param_type_begin(), 5135 Proto1->param_type_end()); 5136 Args2.insert(Args2.end(), Proto2->param_type_begin(), 5137 Proto2->param_type_end()); 5138 5139 // C++ [temp.func.order]p5: 5140 // The presence of unused ellipsis and default arguments has no effect on 5141 // the partial ordering of function templates. 5142 if (Args1.size() > NumComparedArguments) 5143 Args1.resize(NumComparedArguments); 5144 if (Args2.size() > NumComparedArguments) 5145 Args2.resize(NumComparedArguments); 5146 if (Reversed) 5147 std::reverse(Args2.begin(), Args2.end()); 5148 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(), 5149 Args1.data(), Args1.size(), Info, Deduced, 5150 TDF_None, /*PartialOrdering=*/true)) 5151 return false; 5152 5153 break; 5154 } 5155 5156 case TPOC_Conversion: 5157 // - In the context of a call to a conversion operator, the return types 5158 // of the conversion function templates are used. 5159 if (DeduceTemplateArgumentsByTypeMatch( 5160 S, TemplateParams, Proto2->getReturnType(), Proto1->getReturnType(), 5161 Info, Deduced, TDF_None, 5162 /*PartialOrdering=*/true)) 5163 return false; 5164 break; 5165 5166 case TPOC_Other: 5167 // - In other contexts (14.6.6.2) the function template's function type 5168 // is used. 5169 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 5170 FD2->getType(), FD1->getType(), 5171 Info, Deduced, TDF_None, 5172 /*PartialOrdering=*/true)) 5173 return false; 5174 break; 5175 } 5176 5177 // C++0x [temp.deduct.partial]p11: 5178 // In most cases, all template parameters must have values in order for 5179 // deduction to succeed, but for partial ordering purposes a template 5180 // parameter may remain without a value provided it is not used in the 5181 // types being used for partial ordering. [ Note: a template parameter used 5182 // in a non-deduced context is considered used. -end note] 5183 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 5184 for (; ArgIdx != NumArgs; ++ArgIdx) 5185 if (Deduced[ArgIdx].isNull()) 5186 break; 5187 5188 // FIXME: We fail to implement [temp.deduct.type]p1 along this path. We need 5189 // to substitute the deduced arguments back into the template and check that 5190 // we get the right type. 5191 5192 if (ArgIdx == NumArgs) { 5193 // All template arguments were deduced. FT1 is at least as specialized 5194 // as FT2. 5195 return true; 5196 } 5197 5198 // Figure out which template parameters were used. 5199 llvm::SmallBitVector UsedParameters(TemplateParams->size()); 5200 switch (TPOC) { 5201 case TPOC_Call: 5202 for (unsigned I = 0, N = Args2.size(); I != N; ++I) 5203 ::MarkUsedTemplateParameters(S.Context, Args2[I], false, 5204 TemplateParams->getDepth(), 5205 UsedParameters); 5206 break; 5207 5208 case TPOC_Conversion: 5209 ::MarkUsedTemplateParameters(S.Context, Proto2->getReturnType(), false, 5210 TemplateParams->getDepth(), UsedParameters); 5211 break; 5212 5213 case TPOC_Other: 5214 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false, 5215 TemplateParams->getDepth(), 5216 UsedParameters); 5217 break; 5218 } 5219 5220 for (; ArgIdx != NumArgs; ++ArgIdx) 5221 // If this argument had no value deduced but was used in one of the types 5222 // used for partial ordering, then deduction fails. 5223 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 5224 return false; 5225 5226 return true; 5227} 5228 5229/// Determine whether this a function template whose parameter-type-list 5230/// ends with a function parameter pack. 5231static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) { 5232 FunctionDecl *Function = FunTmpl->getTemplatedDecl(); 5233 unsigned NumParams = Function->getNumParams(); 5234 if (NumParams == 0) 5235 return false; 5236 5237 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1); 5238 if (!Last->isParameterPack()) 5239 return false; 5240 5241 // Make sure that no previous parameter is a parameter pack. 5242 while (--NumParams > 0) { 5243 if (Function->getParamDecl(NumParams - 1)->isParameterPack()) 5244 return false; 5245 } 5246 5247 return true; 5248} 5249 5250/// Returns the more specialized function template according 5251/// to the rules of function template partial ordering (C++ [temp.func.order]). 5252/// 5253/// \param FT1 the first function template 5254/// 5255/// \param FT2 the second function template 5256/// 5257/// \param TPOC the context in which we are performing partial ordering of 5258/// function templates. 5259/// 5260/// \param NumCallArguments1 The number of arguments in the call to FT1, used 5261/// only when \c TPOC is \c TPOC_Call. 5262/// 5263/// \param NumCallArguments2 The number of arguments in the call to FT2, used 5264/// only when \c TPOC is \c TPOC_Call. 5265/// 5266/// \param Reversed If \c true, exactly one of FT1 and FT2 is an overload 5267/// candidate with a reversed parameter order. In this case, the corresponding 5268/// P/A pairs between FT1 and FT2 are reversed. 5269/// 5270/// \returns the more specialized function template. If neither 5271/// template is more specialized, returns NULL. 5272FunctionTemplateDecl * 5273Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 5274 FunctionTemplateDecl *FT2, 5275 SourceLocation Loc, 5276 TemplatePartialOrderingContext TPOC, 5277 unsigned NumCallArguments1, 5278 unsigned NumCallArguments2, 5279 bool Reversed) { 5280 5281 auto JudgeByConstraints = [&] () -> FunctionTemplateDecl * { 5282 llvm::SmallVector<const Expr *, 3> AC1, AC2; 5283 FT1->getAssociatedConstraints(AC1); 5284 FT2->getAssociatedConstraints(AC2); 5285 bool AtLeastAsConstrained1, AtLeastAsConstrained2; 5286 if (IsAtLeastAsConstrained(FT1, AC1, FT2, AC2, AtLeastAsConstrained1)) 5287 return nullptr; 5288 if (IsAtLeastAsConstrained(FT2, AC2, FT1, AC1, AtLeastAsConstrained2)) 5289 return nullptr; 5290 if (AtLeastAsConstrained1 == AtLeastAsConstrained2) 5291 return nullptr; 5292 return AtLeastAsConstrained1 ? FT1 : FT2; 5293 }; 5294 5295 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 5296 NumCallArguments1, Reversed); 5297 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 5298 NumCallArguments2, Reversed); 5299 5300 if (Better1 != Better2) // We have a clear winner 5301 return Better1 ? FT1 : FT2; 5302 5303 if (!Better1 && !Better2) // Neither is better than the other 5304 return JudgeByConstraints(); 5305 5306 // FIXME: This mimics what GCC implements, but doesn't match up with the 5307 // proposed resolution for core issue 692. This area needs to be sorted out, 5308 // but for now we attempt to maintain compatibility. 5309 bool Variadic1 = isVariadicFunctionTemplate(FT1); 5310 bool Variadic2 = isVariadicFunctionTemplate(FT2); 5311 if (Variadic1 != Variadic2) 5312 return Variadic1? FT2 : FT1; 5313 5314 return JudgeByConstraints(); 5315} 5316 5317/// Determine if the two templates are equivalent. 5318static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 5319 if (T1 == T2) 5320 return true; 5321 5322 if (!T1 || !T2) 5323 return false; 5324 5325 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 5326} 5327 5328/// Retrieve the most specialized of the given function template 5329/// specializations. 5330/// 5331/// \param SpecBegin the start iterator of the function template 5332/// specializations that we will be comparing. 5333/// 5334/// \param SpecEnd the end iterator of the function template 5335/// specializations, paired with \p SpecBegin. 5336/// 5337/// \param Loc the location where the ambiguity or no-specializations 5338/// diagnostic should occur. 5339/// 5340/// \param NoneDiag partial diagnostic used to diagnose cases where there are 5341/// no matching candidates. 5342/// 5343/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 5344/// occurs. 5345/// 5346/// \param CandidateDiag partial diagnostic used for each function template 5347/// specialization that is a candidate in the ambiguous ordering. One parameter 5348/// in this diagnostic should be unbound, which will correspond to the string 5349/// describing the template arguments for the function template specialization. 5350/// 5351/// \returns the most specialized function template specialization, if 5352/// found. Otherwise, returns SpecEnd. 5353UnresolvedSetIterator Sema::getMostSpecialized( 5354 UnresolvedSetIterator SpecBegin, UnresolvedSetIterator SpecEnd, 5355 TemplateSpecCandidateSet &FailedCandidates, 5356 SourceLocation Loc, const PartialDiagnostic &NoneDiag, 5357 const PartialDiagnostic &AmbigDiag, const PartialDiagnostic &CandidateDiag, 5358 bool Complain, QualType TargetType) { 5359 if (SpecBegin == SpecEnd) { 5360 if (Complain) { 5361 Diag(Loc, NoneDiag); 5362 FailedCandidates.NoteCandidates(*this, Loc); 5363 } 5364 return SpecEnd; 5365 } 5366 5367 if (SpecBegin + 1 == SpecEnd) 5368 return SpecBegin; 5369 5370 // Find the function template that is better than all of the templates it 5371 // has been compared to. 5372 UnresolvedSetIterator Best = SpecBegin; 5373 FunctionTemplateDecl *BestTemplate 5374 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 5375 assert(BestTemplate && "Not a function template specialization?")((void)0); 5376 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 5377 FunctionTemplateDecl *Challenger 5378 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 5379 assert(Challenger && "Not a function template specialization?")((void)0); 5380 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 5381 Loc, TPOC_Other, 0, 0), 5382 Challenger)) { 5383 Best = I; 5384 BestTemplate = Challenger; 5385 } 5386 } 5387 5388 // Make sure that the "best" function template is more specialized than all 5389 // of the others. 5390 bool Ambiguous = false; 5391 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 5392 FunctionTemplateDecl *Challenger 5393 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 5394 if (I != Best && 5395 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 5396 Loc, TPOC_Other, 0, 0), 5397 BestTemplate)) { 5398 Ambiguous = true; 5399 break; 5400 } 5401 } 5402 5403 if (!Ambiguous) { 5404 // We found an answer. Return it. 5405 return Best; 5406 } 5407 5408 // Diagnose the ambiguity. 5409 if (Complain) { 5410 Diag(Loc, AmbigDiag); 5411 5412 // FIXME: Can we order the candidates in some sane way? 5413 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 5414 PartialDiagnostic PD = CandidateDiag; 5415 const auto *FD = cast<FunctionDecl>(*I); 5416 PD << FD << getTemplateArgumentBindingsText( 5417 FD->getPrimaryTemplate()->getTemplateParameters(), 5418 *FD->getTemplateSpecializationArgs()); 5419 if (!TargetType.isNull()) 5420 HandleFunctionTypeMismatch(PD, FD->getType(), TargetType); 5421 Diag((*I)->getLocation(), PD); 5422 } 5423 } 5424 5425 return SpecEnd; 5426} 5427 5428/// Determine whether one partial specialization, P1, is at least as 5429/// specialized than another, P2. 5430/// 5431/// \tparam TemplateLikeDecl The kind of P2, which must be a 5432/// TemplateDecl or {Class,Var}TemplatePartialSpecializationDecl. 5433/// \param T1 The injected-class-name of P1 (faked for a variable template). 5434/// \param T2 The injected-class-name of P2 (faked for a variable template). 5435template<typename TemplateLikeDecl> 5436static bool isAtLeastAsSpecializedAs(Sema &S, QualType T1, QualType T2, 5437 TemplateLikeDecl *P2, 5438 TemplateDeductionInfo &Info) { 5439 // C++ [temp.class.order]p1: 5440 // For two class template partial specializations, the first is at least as 5441 // specialized as the second if, given the following rewrite to two 5442 // function templates, the first function template is at least as 5443 // specialized as the second according to the ordering rules for function 5444 // templates (14.6.6.2): 5445 // - the first function template has the same template parameters as the 5446 // first partial specialization and has a single function parameter 5447 // whose type is a class template specialization with the template 5448 // arguments of the first partial specialization, and 5449 // - the second function template has the same template parameters as the 5450 // second partial specialization and has a single function parameter 5451 // whose type is a class template specialization with the template 5452 // arguments of the second partial specialization. 5453 // 5454 // Rather than synthesize function templates, we merely perform the 5455 // equivalent partial ordering by performing deduction directly on 5456 // the template arguments of the class template partial 5457 // specializations. This computation is slightly simpler than the 5458 // general problem of function template partial ordering, because 5459 // class template partial specializations are more constrained. We 5460 // know that every template parameter is deducible from the class 5461 // template partial specialization's template arguments, for 5462 // example. 5463 SmallVector<DeducedTemplateArgument, 4> Deduced; 5464 5465 // Determine whether P1 is at least as specialized as P2. 5466 Deduced.resize(P2->getTemplateParameters()->size()); 5467 if (DeduceTemplateArgumentsByTypeMatch(S, P2->getTemplateParameters(), 5468 T2, T1, Info, Deduced, TDF_None, 5469 /*PartialOrdering=*/true)) 5470 return false; 5471 5472 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), 5473 Deduced.end()); 5474 Sema::InstantiatingTemplate Inst(S, Info.getLocation(), P2, DeducedArgs, 5475 Info); 5476 if (Inst.isInvalid()) 5477 return false; 5478 5479 auto *TST1 = T1->castAs<TemplateSpecializationType>(); 5480 bool AtLeastAsSpecialized; 5481 S.runWithSufficientStackSpace(Info.getLocation(), [&] { 5482 AtLeastAsSpecialized = !FinishTemplateArgumentDeduction( 5483 S, P2, /*IsPartialOrdering=*/true, 5484 TemplateArgumentList(TemplateArgumentList::OnStack, 5485 TST1->template_arguments()), 5486 Deduced, Info); 5487 }); 5488 return AtLeastAsSpecialized; 5489} 5490 5491/// Returns the more specialized class template partial specialization 5492/// according to the rules of partial ordering of class template partial 5493/// specializations (C++ [temp.class.order]). 5494/// 5495/// \param PS1 the first class template partial specialization 5496/// 5497/// \param PS2 the second class template partial specialization 5498/// 5499/// \returns the more specialized class template partial specialization. If 5500/// neither partial specialization is more specialized, returns NULL. 5501ClassTemplatePartialSpecializationDecl * 5502Sema::getMoreSpecializedPartialSpecialization( 5503 ClassTemplatePartialSpecializationDecl *PS1, 5504 ClassTemplatePartialSpecializationDecl *PS2, 5505 SourceLocation Loc) { 5506 QualType PT1 = PS1->getInjectedSpecializationType(); 5507 QualType PT2 = PS2->getInjectedSpecializationType(); 5508 5509 TemplateDeductionInfo Info(Loc); 5510 bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info); 5511 bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info); 5512 5513 if (!Better1 && !Better2) 5514 return nullptr; 5515 if (Better1 && Better2) { 5516 llvm::SmallVector<const Expr *, 3> AC1, AC2; 5517 PS1->getAssociatedConstraints(AC1); 5518 PS2->getAssociatedConstraints(AC2); 5519 bool AtLeastAsConstrained1, AtLeastAsConstrained2; 5520 if (IsAtLeastAsConstrained(PS1, AC1, PS2, AC2, AtLeastAsConstrained1)) 5521 return nullptr; 5522 if (IsAtLeastAsConstrained(PS2, AC2, PS1, AC1, AtLeastAsConstrained2)) 5523 return nullptr; 5524 if (AtLeastAsConstrained1 == AtLeastAsConstrained2) 5525 return nullptr; 5526 return AtLeastAsConstrained1 ? PS1 : PS2; 5527 } 5528 5529 return Better1 ? PS1 : PS2; 5530} 5531 5532bool Sema::isMoreSpecializedThanPrimary( 5533 ClassTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) { 5534 ClassTemplateDecl *Primary = Spec->getSpecializedTemplate(); 5535 QualType PrimaryT = Primary->getInjectedClassNameSpecialization(); 5536 QualType PartialT = Spec->getInjectedSpecializationType(); 5537 if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info)) 5538 return false; 5539 if (!isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info)) 5540 return true; 5541 Info.clearSFINAEDiagnostic(); 5542 llvm::SmallVector<const Expr *, 3> PrimaryAC, SpecAC; 5543 Primary->getAssociatedConstraints(PrimaryAC); 5544 Spec->getAssociatedConstraints(SpecAC); 5545 bool AtLeastAsConstrainedPrimary, AtLeastAsConstrainedSpec; 5546 if (IsAtLeastAsConstrained(Spec, SpecAC, Primary, PrimaryAC, 5547 AtLeastAsConstrainedSpec)) 5548 return false; 5549 if (!AtLeastAsConstrainedSpec) 5550 return false; 5551 if (IsAtLeastAsConstrained(Primary, PrimaryAC, Spec, SpecAC, 5552 AtLeastAsConstrainedPrimary)) 5553 return false; 5554 return !AtLeastAsConstrainedPrimary; 5555} 5556 5557VarTemplatePartialSpecializationDecl * 5558Sema::getMoreSpecializedPartialSpecialization( 5559 VarTemplatePartialSpecializationDecl *PS1, 5560 VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc) { 5561 // Pretend the variable template specializations are class template 5562 // specializations and form a fake injected class name type for comparison. 5563 assert(PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() &&((void)0) 5564 "the partial specializations being compared should specialize"((void)0) 5565 " the same template.")((void)0); 5566 TemplateName Name(PS1->getSpecializedTemplate()); 5567 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name); 5568 QualType PT1 = Context.getTemplateSpecializationType( 5569 CanonTemplate, PS1->getTemplateArgs().asArray()); 5570 QualType PT2 = Context.getTemplateSpecializationType( 5571 CanonTemplate, PS2->getTemplateArgs().asArray()); 5572 5573 TemplateDeductionInfo Info(Loc); 5574 bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info); 5575 bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info); 5576 5577 if (!Better1 && !Better2) 5578 return nullptr; 5579 if (Better1 && Better2) { 5580 llvm::SmallVector<const Expr *, 3> AC1, AC2; 5581 PS1->getAssociatedConstraints(AC1); 5582 PS2->getAssociatedConstraints(AC2); 5583 bool AtLeastAsConstrained1, AtLeastAsConstrained2; 5584 if (IsAtLeastAsConstrained(PS1, AC1, PS2, AC2, AtLeastAsConstrained1)) 5585 return nullptr; 5586 if (IsAtLeastAsConstrained(PS2, AC2, PS1, AC1, AtLeastAsConstrained2)) 5587 return nullptr; 5588 if (AtLeastAsConstrained1 == AtLeastAsConstrained2) 5589 return nullptr; 5590 return AtLeastAsConstrained1 ? PS1 : PS2; 5591 } 5592 5593 return Better1 ? PS1 : PS2; 5594} 5595 5596bool Sema::isMoreSpecializedThanPrimary( 5597 VarTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) { 5598 TemplateDecl *Primary = Spec->getSpecializedTemplate(); 5599 // FIXME: Cache the injected template arguments rather than recomputing 5600 // them for each partial specialization. 5601 SmallVector<TemplateArgument, 8> PrimaryArgs; 5602 Context.getInjectedTemplateArgs(Primary->getTemplateParameters(), 5603 PrimaryArgs); 5604 5605 TemplateName CanonTemplate = 5606 Context.getCanonicalTemplateName(TemplateName(Primary)); 5607 QualType PrimaryT = Context.getTemplateSpecializationType( 5608 CanonTemplate, PrimaryArgs); 5609 QualType PartialT = Context.getTemplateSpecializationType( 5610 CanonTemplate, Spec->getTemplateArgs().asArray()); 5611 5612 if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info)) 5613 return false; 5614 if (!isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info)) 5615 return true; 5616 Info.clearSFINAEDiagnostic(); 5617 llvm::SmallVector<const Expr *, 3> PrimaryAC, SpecAC; 5618 Primary->getAssociatedConstraints(PrimaryAC); 5619 Spec->getAssociatedConstraints(SpecAC); 5620 bool AtLeastAsConstrainedPrimary, AtLeastAsConstrainedSpec; 5621 if (IsAtLeastAsConstrained(Spec, SpecAC, Primary, PrimaryAC, 5622 AtLeastAsConstrainedSpec)) 5623 return false; 5624 if (!AtLeastAsConstrainedSpec) 5625 return false; 5626 if (IsAtLeastAsConstrained(Primary, PrimaryAC, Spec, SpecAC, 5627 AtLeastAsConstrainedPrimary)) 5628 return false; 5629 return !AtLeastAsConstrainedPrimary; 5630} 5631 5632bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs( 5633 TemplateParameterList *P, TemplateDecl *AArg, SourceLocation Loc) { 5634 // C++1z [temp.arg.template]p4: (DR 150) 5635 // A template template-parameter P is at least as specialized as a 5636 // template template-argument A if, given the following rewrite to two 5637 // function templates... 5638 5639 // Rather than synthesize function templates, we merely perform the 5640 // equivalent partial ordering by performing deduction directly on 5641 // the template parameter lists of the template template parameters. 5642 // 5643 // Given an invented class template X with the template parameter list of 5644 // A (including default arguments): 5645 TemplateName X = Context.getCanonicalTemplateName(TemplateName(AArg)); 5646 TemplateParameterList *A = AArg->getTemplateParameters(); 5647 5648 // - Each function template has a single function parameter whose type is 5649 // a specialization of X with template arguments corresponding to the 5650 // template parameters from the respective function template 5651 SmallVector<TemplateArgument, 8> AArgs; 5652 Context.getInjectedTemplateArgs(A, AArgs); 5653 5654 // Check P's arguments against A's parameter list. This will fill in default 5655 // template arguments as needed. AArgs are already correct by construction. 5656 // We can't just use CheckTemplateIdType because that will expand alias 5657 // templates. 5658 SmallVector<TemplateArgument, 4> PArgs; 5659 { 5660 SFINAETrap Trap(*this); 5661 5662 Context.getInjectedTemplateArgs(P, PArgs); 5663 TemplateArgumentListInfo PArgList(P->getLAngleLoc(), 5664 P->getRAngleLoc()); 5665 for (unsigned I = 0, N = P->size(); I != N; ++I) { 5666 // Unwrap packs that getInjectedTemplateArgs wrapped around pack 5667 // expansions, to form an "as written" argument list. 5668 TemplateArgument Arg = PArgs[I]; 5669 if (Arg.getKind() == TemplateArgument::Pack) { 5670 assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion())((void)0); 5671 Arg = *Arg.pack_begin(); 5672 } 5673 PArgList.addArgument(getTrivialTemplateArgumentLoc( 5674 Arg, QualType(), P->getParam(I)->getLocation())); 5675 } 5676 PArgs.clear(); 5677 5678 // C++1z [temp.arg.template]p3: 5679 // If the rewrite produces an invalid type, then P is not at least as 5680 // specialized as A. 5681 if (CheckTemplateArgumentList(AArg, Loc, PArgList, false, PArgs) || 5682 Trap.hasErrorOccurred()) 5683 return false; 5684 } 5685 5686 QualType AType = Context.getTemplateSpecializationType(X, AArgs); 5687 QualType PType = Context.getTemplateSpecializationType(X, PArgs); 5688 5689 // ... the function template corresponding to P is at least as specialized 5690 // as the function template corresponding to A according to the partial 5691 // ordering rules for function templates. 5692 TemplateDeductionInfo Info(Loc, A->getDepth()); 5693 return isAtLeastAsSpecializedAs(*this, PType, AType, AArg, Info); 5694} 5695 5696namespace { 5697struct MarkUsedTemplateParameterVisitor : 5698 RecursiveASTVisitor<MarkUsedTemplateParameterVisitor> { 5699 llvm::SmallBitVector &Used; 5700 unsigned Depth; 5701 5702 MarkUsedTemplateParameterVisitor(llvm::SmallBitVector &Used, 5703 unsigned Depth) 5704 : Used(Used), Depth(Depth) { } 5705 5706 bool VisitTemplateTypeParmType(TemplateTypeParmType *T) { 5707 if (T->getDepth() == Depth) 5708 Used[T->getIndex()] = true; 5709 return true; 5710 } 5711 5712 bool TraverseTemplateName(TemplateName Template) { 5713 if (auto *TTP = 5714 dyn_cast<TemplateTemplateParmDecl>(Template.getAsTemplateDecl())) 5715 if (TTP->getDepth() == Depth) 5716 Used[TTP->getIndex()] = true; 5717 RecursiveASTVisitor<MarkUsedTemplateParameterVisitor>:: 5718 TraverseTemplateName(Template); 5719 return true; 5720 } 5721 5722 bool VisitDeclRefExpr(DeclRefExpr *E) { 5723 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(E->getDecl())) 5724 if (NTTP->getDepth() == Depth) 5725 Used[NTTP->getIndex()] = true; 5726 return true; 5727 } 5728}; 5729} 5730 5731/// Mark the template parameters that are used by the given 5732/// expression. 5733static void 5734MarkUsedTemplateParameters(ASTContext &Ctx, 5735 const Expr *E, 5736 bool OnlyDeduced, 5737 unsigned Depth, 5738 llvm::SmallBitVector &Used) { 5739 if (!OnlyDeduced) { 5740 MarkUsedTemplateParameterVisitor(Used, Depth) 5741 .TraverseStmt(const_cast<Expr *>(E)); 5742 return; 5743 } 5744 5745 // We can deduce from a pack expansion. 5746 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E)) 5747 E = Expansion->getPattern(); 5748 5749 const NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(E, Depth); 5750 if (!NTTP) 5751 return; 5752 5753 if (NTTP->getDepth() == Depth) 5754 Used[NTTP->getIndex()] = true; 5755 5756 // In C++17 mode, additional arguments may be deduced from the type of a 5757 // non-type argument. 5758 if (Ctx.getLangOpts().CPlusPlus17) 5759 MarkUsedTemplateParameters(Ctx, NTTP->getType(), OnlyDeduced, Depth, Used); 5760} 5761 5762/// Mark the template parameters that are used by the given 5763/// nested name specifier. 5764static void 5765MarkUsedTemplateParameters(ASTContext &Ctx, 5766 NestedNameSpecifier *NNS, 5767 bool OnlyDeduced, 5768 unsigned Depth, 5769 llvm::SmallBitVector &Used) { 5770 if (!NNS) 5771 return; 5772 5773 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth, 5774 Used); 5775 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0), 5776 OnlyDeduced, Depth, Used); 5777} 5778 5779/// Mark the template parameters that are used by the given 5780/// template name. 5781static void 5782MarkUsedTemplateParameters(ASTContext &Ctx, 5783 TemplateName Name, 5784 bool OnlyDeduced, 5785 unsigned Depth, 5786 llvm::SmallBitVector &Used) { 5787 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 5788 if (TemplateTemplateParmDecl *TTP 5789 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 5790 if (TTP->getDepth() == Depth) 5791 Used[TTP->getIndex()] = true; 5792 } 5793 return; 5794 } 5795 5796 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 5797 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced, 5798 Depth, Used); 5799 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 5800 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced, 5801 Depth, Used); 5802} 5803 5804/// Mark the template parameters that are used by the given 5805/// type. 5806static void 5807MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 5808 bool OnlyDeduced, 5809 unsigned Depth, 5810 llvm::SmallBitVector &Used) { 5811 if (T.isNull()) 5812 return; 5813 5814 // Non-dependent types have nothing deducible 5815 if (!T->isDependentType()) 5816 return; 5817 5818 T = Ctx.getCanonicalType(T); 5819 switch (T->getTypeClass()) { 5820 case Type::Pointer: 5821 MarkUsedTemplateParameters(Ctx, 5822 cast<PointerType>(T)->getPointeeType(), 5823 OnlyDeduced, 5824 Depth, 5825 Used); 5826 break; 5827 5828 case Type::BlockPointer: 5829 MarkUsedTemplateParameters(Ctx, 5830 cast<BlockPointerType>(T)->getPointeeType(), 5831 OnlyDeduced, 5832 Depth, 5833 Used); 5834 break; 5835 5836 case Type::LValueReference: 5837 case Type::RValueReference: 5838 MarkUsedTemplateParameters(Ctx, 5839 cast<ReferenceType>(T)->getPointeeType(), 5840 OnlyDeduced, 5841 Depth, 5842 Used); 5843 break; 5844 5845 case Type::MemberPointer: { 5846 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 5847 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced, 5848 Depth, Used); 5849 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0), 5850 OnlyDeduced, Depth, Used); 5851 break; 5852 } 5853 5854 case Type::DependentSizedArray: 5855 MarkUsedTemplateParameters(Ctx, 5856 cast<DependentSizedArrayType>(T)->getSizeExpr(), 5857 OnlyDeduced, Depth, Used); 5858 // Fall through to check the element type 5859 LLVM_FALLTHROUGH[[gnu::fallthrough]]; 5860 5861 case Type::ConstantArray: 5862 case Type::IncompleteArray: 5863 MarkUsedTemplateParameters(Ctx, 5864 cast<ArrayType>(T)->getElementType(), 5865 OnlyDeduced, Depth, Used); 5866 break; 5867 5868 case Type::Vector: 5869 case Type::ExtVector: 5870 MarkUsedTemplateParameters(Ctx, 5871 cast<VectorType>(T)->getElementType(), 5872 OnlyDeduced, Depth, Used); 5873 break; 5874 5875 case Type::DependentVector: { 5876 const auto *VecType = cast<DependentVectorType>(T); 5877 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced, 5878 Depth, Used); 5879 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, Depth, 5880 Used); 5881 break; 5882 } 5883 case Type::DependentSizedExtVector: { 5884 const DependentSizedExtVectorType *VecType 5885 = cast<DependentSizedExtVectorType>(T); 5886 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced, 5887 Depth, Used); 5888 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, 5889 Depth, Used); 5890 break; 5891 } 5892 5893 case Type::DependentAddressSpace: { 5894 const DependentAddressSpaceType *DependentASType = 5895 cast<DependentAddressSpaceType>(T); 5896 MarkUsedTemplateParameters(Ctx, DependentASType->getPointeeType(), 5897 OnlyDeduced, Depth, Used); 5898 MarkUsedTemplateParameters(Ctx, 5899 DependentASType->getAddrSpaceExpr(), 5900 OnlyDeduced, Depth, Used); 5901 break; 5902 } 5903 5904 case Type::ConstantMatrix: { 5905 const ConstantMatrixType *MatType = cast<ConstantMatrixType>(T); 5906 MarkUsedTemplateParameters(Ctx, MatType->getElementType(), OnlyDeduced, 5907 Depth, Used); 5908 break; 5909 } 5910 5911 case Type::DependentSizedMatrix: { 5912 const DependentSizedMatrixType *MatType = cast<DependentSizedMatrixType>(T); 5913 MarkUsedTemplateParameters(Ctx, MatType->getElementType(), OnlyDeduced, 5914 Depth, Used); 5915 MarkUsedTemplateParameters(Ctx, MatType->getRowExpr(), OnlyDeduced, Depth, 5916 Used); 5917 MarkUsedTemplateParameters(Ctx, MatType->getColumnExpr(), OnlyDeduced, 5918 Depth, Used); 5919 break; 5920 } 5921 5922 case Type::FunctionProto: { 5923 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 5924 MarkUsedTemplateParameters(Ctx, Proto->getReturnType(), OnlyDeduced, Depth, 5925 Used); 5926 for (unsigned I = 0, N = Proto->getNumParams(); I != N; ++I) { 5927 // C++17 [temp.deduct.type]p5: 5928 // The non-deduced contexts are: [...] 5929 // -- A function parameter pack that does not occur at the end of the 5930 // parameter-declaration-list. 5931 if (!OnlyDeduced || I + 1 == N || 5932 !Proto->getParamType(I)->getAs<PackExpansionType>()) { 5933 MarkUsedTemplateParameters(Ctx, Proto->getParamType(I), OnlyDeduced, 5934 Depth, Used); 5935 } else { 5936 // FIXME: C++17 [temp.deduct.call]p1: 5937 // When a function parameter pack appears in a non-deduced context, 5938 // the type of that pack is never deduced. 5939 // 5940 // We should also track a set of "never deduced" parameters, and 5941 // subtract that from the list of deduced parameters after marking. 5942 } 5943 } 5944 if (auto *E = Proto->getNoexceptExpr()) 5945 MarkUsedTemplateParameters(Ctx, E, OnlyDeduced, Depth, Used); 5946 break; 5947 } 5948 5949 case Type::TemplateTypeParm: { 5950 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 5951 if (TTP->getDepth() == Depth) 5952 Used[TTP->getIndex()] = true; 5953 break; 5954 } 5955 5956 case Type::SubstTemplateTypeParmPack: { 5957 const SubstTemplateTypeParmPackType *Subst 5958 = cast<SubstTemplateTypeParmPackType>(T); 5959 MarkUsedTemplateParameters(Ctx, 5960 QualType(Subst->getReplacedParameter(), 0), 5961 OnlyDeduced, Depth, Used); 5962 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(), 5963 OnlyDeduced, Depth, Used); 5964 break; 5965 } 5966 5967 case Type::InjectedClassName: 5968 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 5969 LLVM_FALLTHROUGH[[gnu::fallthrough]]; 5970 5971 case Type::TemplateSpecialization: { 5972 const TemplateSpecializationType *Spec 5973 = cast<TemplateSpecializationType>(T); 5974 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced, 5975 Depth, Used); 5976 5977 // C++0x [temp.deduct.type]p9: 5978 // If the template argument list of P contains a pack expansion that is 5979 // not the last template argument, the entire template argument list is a 5980 // non-deduced context. 5981 if (OnlyDeduced && 5982 hasPackExpansionBeforeEnd(Spec->template_arguments())) 5983 break; 5984 5985 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 5986 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 5987 Used); 5988 break; 5989 } 5990 5991 case Type::Complex: 5992 if (!OnlyDeduced) 5993 MarkUsedTemplateParameters(Ctx, 5994 cast<ComplexType>(T)->getElementType(), 5995 OnlyDeduced, Depth, Used); 5996 break; 5997 5998 case Type::Atomic: 5999 if (!OnlyDeduced) 6000 MarkUsedTemplateParameters(Ctx, 6001 cast<AtomicType>(T)->getValueType(), 6002 OnlyDeduced, Depth, Used); 6003 break; 6004 6005 case Type::DependentName: 6006 if (!OnlyDeduced) 6007 MarkUsedTemplateParameters(Ctx, 6008 cast<DependentNameType>(T)->getQualifier(), 6009 OnlyDeduced, Depth, Used); 6010 break; 6011 6012 case Type::DependentTemplateSpecialization: { 6013 // C++14 [temp.deduct.type]p5: 6014 // The non-deduced contexts are: 6015 // -- The nested-name-specifier of a type that was specified using a 6016 // qualified-id 6017 // 6018 // C++14 [temp.deduct.type]p6: 6019 // When a type name is specified in a way that includes a non-deduced 6020 // context, all of the types that comprise that type name are also 6021 // non-deduced. 6022 if (OnlyDeduced) 6023 break; 6024 6025 const DependentTemplateSpecializationType *Spec 6026 = cast<DependentTemplateSpecializationType>(T); 6027 6028 MarkUsedTemplateParameters(Ctx, Spec->getQualifier(), 6029 OnlyDeduced, Depth, Used); 6030 6031 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 6032 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 6033 Used); 6034 break; 6035 } 6036 6037 case Type::TypeOf: 6038 if (!OnlyDeduced) 6039 MarkUsedTemplateParameters(Ctx, 6040 cast<TypeOfType>(T)->getUnderlyingType(), 6041 OnlyDeduced, Depth, Used); 6042 break; 6043 6044 case Type::TypeOfExpr: 6045 if (!OnlyDeduced) 6046 MarkUsedTemplateParameters(Ctx, 6047 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 6048 OnlyDeduced, Depth, Used); 6049 break; 6050 6051 case Type::Decltype: 6052 if (!OnlyDeduced) 6053 MarkUsedTemplateParameters(Ctx, 6054 cast<DecltypeType>(T)->getUnderlyingExpr(), 6055 OnlyDeduced, Depth, Used); 6056 break; 6057 6058 case Type::UnaryTransform: 6059 if (!OnlyDeduced) 6060 MarkUsedTemplateParameters(Ctx, 6061 cast<UnaryTransformType>(T)->getUnderlyingType(), 6062 OnlyDeduced, Depth, Used); 6063 break; 6064 6065 case Type::PackExpansion: 6066 MarkUsedTemplateParameters(Ctx, 6067 cast<PackExpansionType>(T)->getPattern(), 6068 OnlyDeduced, Depth, Used); 6069 break; 6070 6071 case Type::Auto: 6072 case Type::DeducedTemplateSpecialization: 6073 MarkUsedTemplateParameters(Ctx, 6074 cast<DeducedType>(T)->getDeducedType(), 6075 OnlyDeduced, Depth, Used); 6076 break; 6077 case Type::DependentExtInt: 6078 MarkUsedTemplateParameters(Ctx, 6079 cast<DependentExtIntType>(T)->getNumBitsExpr(), 6080 OnlyDeduced, Depth, Used); 6081 break; 6082 6083 // None of these types have any template parameters in them. 6084 case Type::Builtin: 6085 case Type::VariableArray: 6086 case Type::FunctionNoProto: 6087 case Type::Record: 6088 case Type::Enum: 6089 case Type::ObjCInterface: 6090 case Type::ObjCObject: 6091 case Type::ObjCObjectPointer: 6092 case Type::UnresolvedUsing: 6093 case Type::Pipe: 6094 case Type::ExtInt: 6095#define TYPE(Class, Base) 6096#define ABSTRACT_TYPE(Class, Base) 6097#define DEPENDENT_TYPE(Class, Base) 6098#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 6099#include "clang/AST/TypeNodes.inc" 6100 break; 6101 } 6102} 6103 6104/// Mark the template parameters that are used by this 6105/// template argument. 6106static void 6107MarkUsedTemplateParameters(ASTContext &Ctx, 6108 const TemplateArgument &TemplateArg, 6109 bool OnlyDeduced, 6110 unsigned Depth, 6111 llvm::SmallBitVector &Used) { 6112 switch (TemplateArg.getKind()) { 6113 case TemplateArgument::Null: 6114 case TemplateArgument::Integral: 6115 case TemplateArgument::Declaration: 6116 break; 6117 6118 case TemplateArgument::NullPtr: 6119 MarkUsedTemplateParameters(Ctx, TemplateArg.getNullPtrType(), OnlyDeduced, 6120 Depth, Used); 6121 break; 6122 6123 case TemplateArgument::Type: 6124 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced, 6125 Depth, Used); 6126 break; 6127 6128 case TemplateArgument::Template: 6129 case TemplateArgument::TemplateExpansion: 6130 MarkUsedTemplateParameters(Ctx, 6131 TemplateArg.getAsTemplateOrTemplatePattern(), 6132 OnlyDeduced, Depth, Used); 6133 break; 6134 6135 case TemplateArgument::Expression: 6136 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced, 6137 Depth, Used); 6138 break; 6139 6140 case TemplateArgument::Pack: 6141 for (const auto &P : TemplateArg.pack_elements()) 6142 MarkUsedTemplateParameters(Ctx, P, OnlyDeduced, Depth, Used); 6143 break; 6144 } 6145} 6146 6147/// Mark which template parameters are used in a given expression. 6148/// 6149/// \param E the expression from which template parameters will be deduced. 6150/// 6151/// \param Used a bit vector whose elements will be set to \c true 6152/// to indicate when the corresponding template parameter will be 6153/// deduced. 6154void 6155Sema::MarkUsedTemplateParameters(const Expr *E, bool OnlyDeduced, 6156 unsigned Depth, 6157 llvm::SmallBitVector &Used) { 6158 ::MarkUsedTemplateParameters(Context, E, OnlyDeduced, Depth, Used); 6159} 6160 6161/// Mark which template parameters can be deduced from a given 6162/// template argument list. 6163/// 6164/// \param TemplateArgs the template argument list from which template 6165/// parameters will be deduced. 6166/// 6167/// \param Used a bit vector whose elements will be set to \c true 6168/// to indicate when the corresponding template parameter will be 6169/// deduced. 6170void 6171Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 6172 bool OnlyDeduced, unsigned Depth, 6173 llvm::SmallBitVector &Used) { 6174 // C++0x [temp.deduct.type]p9: 6175 // If the template argument list of P contains a pack expansion that is not 6176 // the last template argument, the entire template argument list is a 6177 // non-deduced context. 6178 if (OnlyDeduced && 6179 hasPackExpansionBeforeEnd(TemplateArgs.asArray())) 6180 return; 6181 6182 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 6183 ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced, 6184 Depth, Used); 6185} 6186 6187/// Marks all of the template parameters that will be deduced by a 6188/// call to the given function template. 6189void Sema::MarkDeducedTemplateParameters( 6190 ASTContext &Ctx, const FunctionTemplateDecl *FunctionTemplate, 6191 llvm::SmallBitVector &Deduced) { 6192 TemplateParameterList *TemplateParams 6193 = FunctionTemplate->getTemplateParameters(); 6194 Deduced.clear(); 6195 Deduced.resize(TemplateParams->size()); 6196 6197 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 6198 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 6199 ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(), 6200 true, TemplateParams->getDepth(), Deduced); 6201} 6202 6203bool hasDeducibleTemplateParameters(Sema &S, 6204 FunctionTemplateDecl *FunctionTemplate, 6205 QualType T) { 6206 if (!T->isDependentType()) 6207 return false; 6208 6209 TemplateParameterList *TemplateParams 6210 = FunctionTemplate->getTemplateParameters(); 6211 llvm::SmallBitVector Deduced(TemplateParams->size()); 6212 ::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(), 6213 Deduced); 6214 6215 return Deduced.any(); 6216}