Bug Summary

File:tools/clang/lib/Sema/TreeTransform.h
Warning:line 4641, column 22
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -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 -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=none -relaxed-aliasing -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D CLANG_VENDOR="Debian " -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~svn373517/build-llvm/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema -I /build/llvm-toolchain-snapshot-10~svn373517/tools/clang/include -I /build/llvm-toolchain-snapshot-10~svn373517/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-10~svn373517/build-llvm/include -I /build/llvm-toolchain-snapshot-10~svn373517/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-10~svn373517/build-llvm/tools/clang/lib/Sema -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~svn373517=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fno-common -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2019-10-02-234743-9763-1 -x c++ /build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp

/build/llvm-toolchain-snapshot-10~svn373517/tools/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/TemplateBase.h"
28#include "clang/AST/TemplateName.h"
29#include "clang/AST/Type.h"
30#include "clang/AST/TypeLoc.h"
31#include "clang/AST/UnresolvedSet.h"
32#include "clang/Basic/AddressSpaces.h"
33#include "clang/Basic/ExceptionSpecificationType.h"
34#include "clang/Basic/LLVM.h"
35#include "clang/Basic/LangOptions.h"
36#include "clang/Basic/PartialDiagnostic.h"
37#include "clang/Basic/SourceLocation.h"
38#include "clang/Basic/Specifiers.h"
39#include "clang/Sema/Ownership.h"
40#include "clang/Sema/Sema.h"
41#include "clang/Sema/Template.h"
42#include "llvm/ADT/APInt.h"
43#include "llvm/ADT/APSInt.h"
44#include "llvm/ADT/ArrayRef.h"
45#include "llvm/ADT/DenseMap.h"
46#include "llvm/ADT/FoldingSet.h"
47#include "llvm/ADT/Optional.h"
48#include "llvm/ADT/SmallBitVector.h"
49#include "llvm/ADT/SmallPtrSet.h"
50#include "llvm/ADT/SmallVector.h"
51#include "llvm/Support/Casting.h"
52#include "llvm/Support/Compiler.h"
53#include "llvm/Support/ErrorHandling.h"
54#include <algorithm>
55#include <cassert>
56#include <tuple>
57#include <utility>
58
59namespace clang {
60
61 /// Various flags that control template argument deduction.
62 ///
63 /// These flags can be bitwise-OR'd together.
64 enum TemplateDeductionFlags {
65 /// No template argument deduction flags, which indicates the
66 /// strictest results for template argument deduction (as used for, e.g.,
67 /// matching class template partial specializations).
68 TDF_None = 0,
69
70 /// Within template argument deduction from a function call, we are
71 /// matching with a parameter type for which the original parameter was
72 /// a reference.
73 TDF_ParamWithReferenceType = 0x1,
74
75 /// Within template argument deduction from a function call, we
76 /// are matching in a case where we ignore cv-qualifiers.
77 TDF_IgnoreQualifiers = 0x02,
78
79 /// Within template argument deduction from a function call,
80 /// we are matching in a case where we can perform template argument
81 /// deduction from a template-id of a derived class of the argument type.
82 TDF_DerivedClass = 0x04,
83
84 /// Allow non-dependent types to differ, e.g., when performing
85 /// template argument deduction from a function call where conversions
86 /// may apply.
87 TDF_SkipNonDependent = 0x08,
88
89 /// Whether we are performing template argument deduction for
90 /// parameters and arguments in a top-level template argument
91 TDF_TopLevelParameterTypeList = 0x10,
92
93 /// Within template argument deduction from overload resolution per
94 /// C++ [over.over] allow matching function types that are compatible in
95 /// terms of noreturn and default calling convention adjustments, or
96 /// similarly matching a declared template specialization against a
97 /// possible template, per C++ [temp.deduct.decl]. In either case, permit
98 /// deduction where the parameter is a function type that can be converted
99 /// to the argument type.
100 TDF_AllowCompatibleFunctionType = 0x20,
101
102 /// Within template argument deduction for a conversion function, we are
103 /// matching with an argument type for which the original argument was
104 /// a reference.
105 TDF_ArgWithReferenceType = 0x40,
106 };
107}
108
109using namespace clang;
110using namespace sema;
111
112/// Compare two APSInts, extending and switching the sign as
113/// necessary to compare their values regardless of underlying type.
114static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) {
115 if (Y.getBitWidth() > X.getBitWidth())
116 X = X.extend(Y.getBitWidth());
117 else if (Y.getBitWidth() < X.getBitWidth())
118 Y = Y.extend(X.getBitWidth());
119
120 // If there is a signedness mismatch, correct it.
121 if (X.isSigned() != Y.isSigned()) {
122 // If the signed value is negative, then the values cannot be the same.
123 if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative()))
124 return false;
125
126 Y.setIsSigned(true);
127 X.setIsSigned(true);
128 }
129
130 return X == Y;
131}
132
133static Sema::TemplateDeductionResult
134DeduceTemplateArguments(Sema &S,
135 TemplateParameterList *TemplateParams,
136 const TemplateArgument &Param,
137 TemplateArgument Arg,
138 TemplateDeductionInfo &Info,
139 SmallVectorImpl<DeducedTemplateArgument> &Deduced);
140
141static Sema::TemplateDeductionResult
142DeduceTemplateArgumentsByTypeMatch(Sema &S,
143 TemplateParameterList *TemplateParams,
144 QualType Param,
145 QualType Arg,
146 TemplateDeductionInfo &Info,
147 SmallVectorImpl<DeducedTemplateArgument> &
148 Deduced,
149 unsigned TDF,
150 bool PartialOrdering = false,
151 bool DeducedFromArrayBound = false);
152
153static Sema::TemplateDeductionResult
154DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
155 ArrayRef<TemplateArgument> Params,
156 ArrayRef<TemplateArgument> Args,
157 TemplateDeductionInfo &Info,
158 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
159 bool NumberOfArgumentsMustMatch);
160
161static void MarkUsedTemplateParameters(ASTContext &Ctx,
162 const TemplateArgument &TemplateArg,
163 bool OnlyDeduced, unsigned Depth,
164 llvm::SmallBitVector &Used);
165
166static void MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
167 bool OnlyDeduced, unsigned Level,
168 llvm::SmallBitVector &Deduced);
169
170/// If the given expression is of a form that permits the deduction
171/// of a non-type template parameter, return the declaration of that
172/// non-type template parameter.
173static NonTypeTemplateParmDecl *
174getDeducedParameterFromExpr(TemplateDeductionInfo &Info, Expr *E) {
175 // If we are within an alias template, the expression may have undergone
176 // any number of parameter substitutions already.
177 while (true) {
178 if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
179 E = IC->getSubExpr();
180 else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(E))
181 E = CE->getSubExpr();
182 else if (SubstNonTypeTemplateParmExpr *Subst =
183 dyn_cast<SubstNonTypeTemplateParmExpr>(E))
184 E = Subst->getReplacement();
185 else
186 break;
187 }
188
189 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
190 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()))
191 if (NTTP->getDepth() == Info.getDeducedDepth())
192 return NTTP;
193
194 return nullptr;
195}
196
197/// Determine whether two declaration pointers refer to the same
198/// declaration.
199static bool isSameDeclaration(Decl *X, Decl *Y) {
200 if (NamedDecl *NX = dyn_cast<NamedDecl>(X))
201 X = NX->getUnderlyingDecl();
202 if (NamedDecl *NY = dyn_cast<NamedDecl>(Y))
203 Y = NY->getUnderlyingDecl();
204
205 return X->getCanonicalDecl() == Y->getCanonicalDecl();
206}
207
208/// Verify that the given, deduced template arguments are compatible.
209///
210/// \returns The deduced template argument, or a NULL template argument if
211/// the deduced template arguments were incompatible.
212static DeducedTemplateArgument
213checkDeducedTemplateArguments(ASTContext &Context,
214 const DeducedTemplateArgument &X,
215 const DeducedTemplateArgument &Y) {
216 // We have no deduction for one or both of the arguments; they're compatible.
217 if (X.isNull())
218 return Y;
219 if (Y.isNull())
220 return X;
221
222 // If we have two non-type template argument values deduced for the same
223 // parameter, they must both match the type of the parameter, and thus must
224 // match each other's type. As we're only keeping one of them, we must check
225 // for that now. The exception is that if either was deduced from an array
226 // bound, the type is permitted to differ.
227 if (!X.wasDeducedFromArrayBound() && !Y.wasDeducedFromArrayBound()) {
228 QualType XType = X.getNonTypeTemplateArgumentType();
229 if (!XType.isNull()) {
230 QualType YType = Y.getNonTypeTemplateArgumentType();
231 if (YType.isNull() || !Context.hasSameType(XType, YType))
232 return DeducedTemplateArgument();
233 }
234 }
235
236 switch (X.getKind()) {
237 case TemplateArgument::Null:
238 llvm_unreachable("Non-deduced template arguments handled above")::llvm::llvm_unreachable_internal("Non-deduced template arguments handled above"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 238)
;
239
240 case TemplateArgument::Type:
241 // If two template type arguments have the same type, they're compatible.
242 if (Y.getKind() == TemplateArgument::Type &&
243 Context.hasSameType(X.getAsType(), Y.getAsType()))
244 return X;
245
246 // If one of the two arguments was deduced from an array bound, the other
247 // supersedes it.
248 if (X.wasDeducedFromArrayBound() != Y.wasDeducedFromArrayBound())
249 return X.wasDeducedFromArrayBound() ? Y : X;
250
251 // The arguments are not compatible.
252 return DeducedTemplateArgument();
253
254 case TemplateArgument::Integral:
255 // If we deduced a constant in one case and either a dependent expression or
256 // declaration in another case, keep the integral constant.
257 // If both are integral constants with the same value, keep that value.
258 if (Y.getKind() == TemplateArgument::Expression ||
259 Y.getKind() == TemplateArgument::Declaration ||
260 (Y.getKind() == TemplateArgument::Integral &&
261 hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
262 return X.wasDeducedFromArrayBound() ? Y : X;
263
264 // All other combinations are incompatible.
265 return DeducedTemplateArgument();
266
267 case TemplateArgument::Template:
268 if (Y.getKind() == TemplateArgument::Template &&
269 Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate()))
270 return X;
271
272 // All other combinations are incompatible.
273 return DeducedTemplateArgument();
274
275 case TemplateArgument::TemplateExpansion:
276 if (Y.getKind() == TemplateArgument::TemplateExpansion &&
277 Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(),
278 Y.getAsTemplateOrTemplatePattern()))
279 return X;
280
281 // All other combinations are incompatible.
282 return DeducedTemplateArgument();
283
284 case TemplateArgument::Expression: {
285 if (Y.getKind() != TemplateArgument::Expression)
286 return checkDeducedTemplateArguments(Context, Y, X);
287
288 // Compare the expressions for equality
289 llvm::FoldingSetNodeID ID1, ID2;
290 X.getAsExpr()->Profile(ID1, Context, true);
291 Y.getAsExpr()->Profile(ID2, Context, true);
292 if (ID1 == ID2)
293 return X.wasDeducedFromArrayBound() ? Y : X;
294
295 // Differing dependent expressions are incompatible.
296 return DeducedTemplateArgument();
297 }
298
299 case TemplateArgument::Declaration:
300 assert(!X.wasDeducedFromArrayBound())((!X.wasDeducedFromArrayBound()) ? static_cast<void> (0
) : __assert_fail ("!X.wasDeducedFromArrayBound()", "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 300, __PRETTY_FUNCTION__))
;
301
302 // If we deduced a declaration and a dependent expression, keep the
303 // declaration.
304 if (Y.getKind() == TemplateArgument::Expression)
305 return X;
306
307 // If we deduced a declaration and an integral constant, keep the
308 // integral constant and whichever type did not come from an array
309 // bound.
310 if (Y.getKind() == TemplateArgument::Integral) {
311 if (Y.wasDeducedFromArrayBound())
312 return TemplateArgument(Context, Y.getAsIntegral(),
313 X.getParamTypeForDecl());
314 return Y;
315 }
316
317 // If we deduced two declarations, make sure that they refer to the
318 // same declaration.
319 if (Y.getKind() == TemplateArgument::Declaration &&
320 isSameDeclaration(X.getAsDecl(), Y.getAsDecl()))
321 return X;
322
323 // All other combinations are incompatible.
324 return DeducedTemplateArgument();
325
326 case TemplateArgument::NullPtr:
327 // If we deduced a null pointer and a dependent expression, keep the
328 // null pointer.
329 if (Y.getKind() == TemplateArgument::Expression)
330 return X;
331
332 // If we deduced a null pointer and an integral constant, keep the
333 // integral constant.
334 if (Y.getKind() == TemplateArgument::Integral)
335 return Y;
336
337 // If we deduced two null pointers, they are the same.
338 if (Y.getKind() == TemplateArgument::NullPtr)
339 return X;
340
341 // All other combinations are incompatible.
342 return DeducedTemplateArgument();
343
344 case TemplateArgument::Pack: {
345 if (Y.getKind() != TemplateArgument::Pack ||
346 X.pack_size() != Y.pack_size())
347 return DeducedTemplateArgument();
348
349 llvm::SmallVector<TemplateArgument, 8> NewPack;
350 for (TemplateArgument::pack_iterator XA = X.pack_begin(),
351 XAEnd = X.pack_end(),
352 YA = Y.pack_begin();
353 XA != XAEnd; ++XA, ++YA) {
354 TemplateArgument Merged = checkDeducedTemplateArguments(
355 Context, DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()),
356 DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound()));
357 if (Merged.isNull())
358 return DeducedTemplateArgument();
359 NewPack.push_back(Merged);
360 }
361
362 return DeducedTemplateArgument(
363 TemplateArgument::CreatePackCopy(Context, NewPack),
364 X.wasDeducedFromArrayBound() && Y.wasDeducedFromArrayBound());
365 }
366 }
367
368 llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 368)
;
369}
370
371/// Deduce the value of the given non-type template parameter
372/// as the given deduced template argument. All non-type template parameter
373/// deduction is funneled through here.
374static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
375 Sema &S, TemplateParameterList *TemplateParams,
376 NonTypeTemplateParmDecl *NTTP, const DeducedTemplateArgument &NewDeduced,
377 QualType ValueType, TemplateDeductionInfo &Info,
378 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
379 assert(NTTP->getDepth() == Info.getDeducedDepth() &&((NTTP->getDepth() == Info.getDeducedDepth() && "deducing non-type template argument with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"deducing non-type template argument with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 380, __PRETTY_FUNCTION__))
380 "deducing non-type template argument with wrong depth")((NTTP->getDepth() == Info.getDeducedDepth() && "deducing non-type template argument with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"deducing non-type template argument with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 380, __PRETTY_FUNCTION__))
;
381
382 DeducedTemplateArgument Result = checkDeducedTemplateArguments(
383 S.Context, Deduced[NTTP->getIndex()], NewDeduced);
384 if (Result.isNull()) {
385 Info.Param = NTTP;
386 Info.FirstArg = Deduced[NTTP->getIndex()];
387 Info.SecondArg = NewDeduced;
388 return Sema::TDK_Inconsistent;
389 }
390
391 Deduced[NTTP->getIndex()] = Result;
392 if (!S.getLangOpts().CPlusPlus17)
393 return Sema::TDK_Success;
394
395 if (NTTP->isExpandedParameterPack())
396 // FIXME: We may still need to deduce parts of the type here! But we
397 // don't have any way to find which slice of the type to use, and the
398 // type stored on the NTTP itself is nonsense. Perhaps the type of an
399 // expanded NTTP should be a pack expansion type?
400 return Sema::TDK_Success;
401
402 // Get the type of the parameter for deduction. If it's a (dependent) array
403 // or function type, we will not have decayed it yet, so do that now.
404 QualType ParamType = S.Context.getAdjustedParameterType(NTTP->getType());
405 if (auto *Expansion = dyn_cast<PackExpansionType>(ParamType))
406 ParamType = Expansion->getPattern();
407
408 // FIXME: It's not clear how deduction of a parameter of reference
409 // type from an argument (of non-reference type) should be performed.
410 // For now, we just remove reference types from both sides and let
411 // the final check for matching types sort out the mess.
412 return DeduceTemplateArgumentsByTypeMatch(
413 S, TemplateParams, ParamType.getNonReferenceType(),
414 ValueType.getNonReferenceType(), Info, Deduced, TDF_SkipNonDependent,
415 /*PartialOrdering=*/false,
416 /*ArrayBound=*/NewDeduced.wasDeducedFromArrayBound());
417}
418
419/// Deduce the value of the given non-type template parameter
420/// from the given integral constant.
421static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
422 Sema &S, TemplateParameterList *TemplateParams,
423 NonTypeTemplateParmDecl *NTTP, const llvm::APSInt &Value,
424 QualType ValueType, bool DeducedFromArrayBound, TemplateDeductionInfo &Info,
425 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
426 return DeduceNonTypeTemplateArgument(
427 S, TemplateParams, NTTP,
428 DeducedTemplateArgument(S.Context, Value, ValueType,
429 DeducedFromArrayBound),
430 ValueType, Info, Deduced);
431}
432
433/// Deduce the value of the given non-type template parameter
434/// from the given null pointer template argument type.
435static Sema::TemplateDeductionResult DeduceNullPtrTemplateArgument(
436 Sema &S, TemplateParameterList *TemplateParams,
437 NonTypeTemplateParmDecl *NTTP, QualType NullPtrType,
438 TemplateDeductionInfo &Info,
439 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
440 Expr *Value =
441 S.ImpCastExprToType(new (S.Context) CXXNullPtrLiteralExpr(
442 S.Context.NullPtrTy, NTTP->getLocation()),
443 NullPtrType, CK_NullToPointer)
444 .get();
445 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
446 DeducedTemplateArgument(Value),
447 Value->getType(), Info, Deduced);
448}
449
450/// Deduce the value of the given non-type template parameter
451/// from the given type- or value-dependent expression.
452///
453/// \returns true if deduction succeeded, false otherwise.
454static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
455 Sema &S, TemplateParameterList *TemplateParams,
456 NonTypeTemplateParmDecl *NTTP, Expr *Value, TemplateDeductionInfo &Info,
457 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
458 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
459 DeducedTemplateArgument(Value),
460 Value->getType(), Info, Deduced);
461}
462
463/// Deduce the value of the given non-type template parameter
464/// from the given declaration.
465///
466/// \returns true if deduction succeeded, false otherwise.
467static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
468 Sema &S, TemplateParameterList *TemplateParams,
469 NonTypeTemplateParmDecl *NTTP, ValueDecl *D, QualType T,
470 TemplateDeductionInfo &Info,
471 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
472 D = D ? cast<ValueDecl>(D->getCanonicalDecl()) : nullptr;
473 TemplateArgument New(D, T);
474 return DeduceNonTypeTemplateArgument(
475 S, TemplateParams, NTTP, DeducedTemplateArgument(New), T, Info, Deduced);
476}
477
478static Sema::TemplateDeductionResult
479DeduceTemplateArguments(Sema &S,
480 TemplateParameterList *TemplateParams,
481 TemplateName Param,
482 TemplateName Arg,
483 TemplateDeductionInfo &Info,
484 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
485 TemplateDecl *ParamDecl = Param.getAsTemplateDecl();
486 if (!ParamDecl) {
487 // The parameter type is dependent and is not a template template parameter,
488 // so there is nothing that we can deduce.
489 return Sema::TDK_Success;
490 }
491
492 if (TemplateTemplateParmDecl *TempParam
493 = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) {
494 // If we're not deducing at this depth, there's nothing to deduce.
495 if (TempParam->getDepth() != Info.getDeducedDepth())
496 return Sema::TDK_Success;
497
498 DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg));
499 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
500 Deduced[TempParam->getIndex()],
501 NewDeduced);
502 if (Result.isNull()) {
503 Info.Param = TempParam;
504 Info.FirstArg = Deduced[TempParam->getIndex()];
505 Info.SecondArg = NewDeduced;
506 return Sema::TDK_Inconsistent;
507 }
508
509 Deduced[TempParam->getIndex()] = Result;
510 return Sema::TDK_Success;
511 }
512
513 // Verify that the two template names are equivalent.
514 if (S.Context.hasSameTemplateName(Param, Arg))
515 return Sema::TDK_Success;
516
517 // Mismatch of non-dependent template parameter to argument.
518 Info.FirstArg = TemplateArgument(Param);
519 Info.SecondArg = TemplateArgument(Arg);
520 return Sema::TDK_NonDeducedMismatch;
521}
522
523/// Deduce the template arguments by comparing the template parameter
524/// type (which is a template-id) with the template argument type.
525///
526/// \param S the Sema
527///
528/// \param TemplateParams the template parameters that we are deducing
529///
530/// \param Param the parameter type
531///
532/// \param Arg the argument type
533///
534/// \param Info information about the template argument deduction itself
535///
536/// \param Deduced the deduced template arguments
537///
538/// \returns the result of template argument deduction so far. Note that a
539/// "success" result means that template argument deduction has not yet failed,
540/// but it may still fail, later, for other reasons.
541static Sema::TemplateDeductionResult
542DeduceTemplateArguments(Sema &S,
543 TemplateParameterList *TemplateParams,
544 const TemplateSpecializationType *Param,
545 QualType Arg,
546 TemplateDeductionInfo &Info,
547 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
548 assert(Arg.isCanonical() && "Argument type must be canonical")((Arg.isCanonical() && "Argument type must be canonical"
) ? static_cast<void> (0) : __assert_fail ("Arg.isCanonical() && \"Argument type must be canonical\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 548, __PRETTY_FUNCTION__))
;
549
550 // Treat an injected-class-name as its underlying template-id.
551 if (auto *Injected = dyn_cast<InjectedClassNameType>(Arg))
552 Arg = Injected->getInjectedSpecializationType();
553
554 // Check whether the template argument is a dependent template-id.
555 if (const TemplateSpecializationType *SpecArg
556 = dyn_cast<TemplateSpecializationType>(Arg)) {
557 // Perform template argument deduction for the template name.
558 if (Sema::TemplateDeductionResult Result
559 = DeduceTemplateArguments(S, TemplateParams,
560 Param->getTemplateName(),
561 SpecArg->getTemplateName(),
562 Info, Deduced))
563 return Result;
564
565
566 // Perform template argument deduction on each template
567 // argument. Ignore any missing/extra arguments, since they could be
568 // filled in by default arguments.
569 return DeduceTemplateArguments(S, TemplateParams,
570 Param->template_arguments(),
571 SpecArg->template_arguments(), Info, Deduced,
572 /*NumberOfArgumentsMustMatch=*/false);
573 }
574
575 // If the argument type is a class template specialization, we
576 // perform template argument deduction using its template
577 // arguments.
578 const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
579 if (!RecordArg) {
580 Info.FirstArg = TemplateArgument(QualType(Param, 0));
581 Info.SecondArg = TemplateArgument(Arg);
582 return Sema::TDK_NonDeducedMismatch;
583 }
584
585 ClassTemplateSpecializationDecl *SpecArg
586 = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
587 if (!SpecArg) {
588 Info.FirstArg = TemplateArgument(QualType(Param, 0));
589 Info.SecondArg = TemplateArgument(Arg);
590 return Sema::TDK_NonDeducedMismatch;
591 }
592
593 // Perform template argument deduction for the template name.
594 if (Sema::TemplateDeductionResult Result
595 = DeduceTemplateArguments(S,
596 TemplateParams,
597 Param->getTemplateName(),
598 TemplateName(SpecArg->getSpecializedTemplate()),
599 Info, Deduced))
600 return Result;
601
602 // Perform template argument deduction for the template arguments.
603 return DeduceTemplateArguments(S, TemplateParams, Param->template_arguments(),
604 SpecArg->getTemplateArgs().asArray(), Info,
605 Deduced, /*NumberOfArgumentsMustMatch=*/true);
606}
607
608/// Determines whether the given type is an opaque type that
609/// might be more qualified when instantiated.
610static bool IsPossiblyOpaquelyQualifiedType(QualType T) {
611 switch (T->getTypeClass()) {
612 case Type::TypeOfExpr:
613 case Type::TypeOf:
614 case Type::DependentName:
615 case Type::Decltype:
616 case Type::UnresolvedUsing:
617 case Type::TemplateTypeParm:
618 return true;
619
620 case Type::ConstantArray:
621 case Type::IncompleteArray:
622 case Type::VariableArray:
623 case Type::DependentSizedArray:
624 return IsPossiblyOpaquelyQualifiedType(
625 cast<ArrayType>(T)->getElementType());
626
627 default:
628 return false;
629 }
630}
631
632/// Helper function to build a TemplateParameter when we don't
633/// know its type statically.
634static TemplateParameter makeTemplateParameter(Decl *D) {
635 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D))
636 return TemplateParameter(TTP);
637 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D))
638 return TemplateParameter(NTTP);
639
640 return TemplateParameter(cast<TemplateTemplateParmDecl>(D));
641}
642
643/// If \p Param is an expanded parameter pack, get the number of expansions.
644static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
645 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param))
646 if (NTTP->isExpandedParameterPack())
647 return NTTP->getNumExpansionTypes();
648
649 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param))
650 if (TTP->isExpandedParameterPack())
651 return TTP->getNumExpansionTemplateParameters();
652
653 return None;
654}
655
656/// A pack that we're currently deducing.
657struct clang::DeducedPack {
658 // The index of the pack.
659 unsigned Index;
660
661 // The old value of the pack before we started deducing it.
662 DeducedTemplateArgument Saved;
663
664 // A deferred value of this pack from an inner deduction, that couldn't be
665 // deduced because this deduction hadn't happened yet.
666 DeducedTemplateArgument DeferredDeduction;
667
668 // The new value of the pack.
669 SmallVector<DeducedTemplateArgument, 4> New;
670
671 // The outer deduction for this pack, if any.
672 DeducedPack *Outer = nullptr;
673
674 DeducedPack(unsigned Index) : Index(Index) {}
675};
676
677namespace {
678
679/// A scope in which we're performing pack deduction.
680class PackDeductionScope {
681public:
682 /// Prepare to deduce the packs named within Pattern.
683 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
684 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
685 TemplateDeductionInfo &Info, TemplateArgument Pattern)
686 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
687 unsigned NumNamedPacks = addPacks(Pattern);
688 finishConstruction(NumNamedPacks);
689 }
690
691 /// Prepare to directly deduce arguments of the parameter with index \p Index.
692 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
693 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
694 TemplateDeductionInfo &Info, unsigned Index)
695 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
696 addPack(Index);
697 finishConstruction(1);
698 }
699
700private:
701 void addPack(unsigned Index) {
702 // Save the deduced template argument for the parameter pack expanded
703 // by this pack expansion, then clear out the deduction.
704 DeducedPack Pack(Index);
705 Pack.Saved = Deduced[Index];
706 Deduced[Index] = TemplateArgument();
707
708 // FIXME: What if we encounter multiple packs with different numbers of
709 // pre-expanded expansions? (This should already have been diagnosed
710 // during substitution.)
711 if (Optional<unsigned> ExpandedPackExpansions =
712 getExpandedPackSize(TemplateParams->getParam(Index)))
713 FixedNumExpansions = ExpandedPackExpansions;
714
715 Packs.push_back(Pack);
716 }
717
718 unsigned addPacks(TemplateArgument Pattern) {
719 // Compute the set of template parameter indices that correspond to
720 // parameter packs expanded by the pack expansion.
721 llvm::SmallBitVector SawIndices(TemplateParams->size());
722
723 auto AddPack = [&](unsigned Index) {
724 if (SawIndices[Index])
725 return;
726 SawIndices[Index] = true;
727 addPack(Index);
728 };
729
730 // First look for unexpanded packs in the pattern.
731 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
732 S.collectUnexpandedParameterPacks(Pattern, Unexpanded);
733 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
734 unsigned Depth, Index;
735 std::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]);
736 if (Depth == Info.getDeducedDepth())
737 AddPack(Index);
738 }
739 assert(!Packs.empty() && "Pack expansion without unexpanded packs?")((!Packs.empty() && "Pack expansion without unexpanded packs?"
) ? static_cast<void> (0) : __assert_fail ("!Packs.empty() && \"Pack expansion without unexpanded packs?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 739, __PRETTY_FUNCTION__))
;
740
741 unsigned NumNamedPacks = Packs.size();
742
743 // We can also have deduced template parameters that do not actually
744 // appear in the pattern, but can be deduced by it (the type of a non-type
745 // template parameter pack, in particular). These won't have prevented us
746 // from partially expanding the pack.
747 llvm::SmallBitVector Used(TemplateParams->size());
748 MarkUsedTemplateParameters(S.Context, Pattern, /*OnlyDeduced*/true,
749 Info.getDeducedDepth(), Used);
750 for (int Index = Used.find_first(); Index != -1;
751 Index = Used.find_next(Index))
752 if (TemplateParams->getParam(Index)->isParameterPack())
753 AddPack(Index);
754
755 return NumNamedPacks;
756 }
757
758 void finishConstruction(unsigned NumNamedPacks) {
759 // Dig out the partially-substituted pack, if there is one.
760 const TemplateArgument *PartialPackArgs = nullptr;
761 unsigned NumPartialPackArgs = 0;
762 std::pair<unsigned, unsigned> PartialPackDepthIndex(-1u, -1u);
763 if (auto *Scope = S.CurrentInstantiationScope)
764 if (auto *Partial = Scope->getPartiallySubstitutedPack(
765 &PartialPackArgs, &NumPartialPackArgs))
766 PartialPackDepthIndex = getDepthAndIndex(Partial);
767
768 // This pack expansion will have been partially or fully expanded if
769 // it only names explicitly-specified parameter packs (including the
770 // partially-substituted one, if any).
771 bool IsExpanded = true;
772 for (unsigned I = 0; I != NumNamedPacks; ++I) {
773 if (Packs[I].Index >= Info.getNumExplicitArgs()) {
774 IsExpanded = false;
775 IsPartiallyExpanded = false;
776 break;
777 }
778 if (PartialPackDepthIndex ==
779 std::make_pair(Info.getDeducedDepth(), Packs[I].Index)) {
780 IsPartiallyExpanded = true;
781 }
782 }
783
784 // Skip over the pack elements that were expanded into separate arguments.
785 // If we partially expanded, this is the number of partial arguments.
786 if (IsPartiallyExpanded)
787 PackElements += NumPartialPackArgs;
788 else if (IsExpanded)
789 PackElements += *FixedNumExpansions;
790
791 for (auto &Pack : Packs) {
792 if (Info.PendingDeducedPacks.size() > Pack.Index)
793 Pack.Outer = Info.PendingDeducedPacks[Pack.Index];
794 else
795 Info.PendingDeducedPacks.resize(Pack.Index + 1);
796 Info.PendingDeducedPacks[Pack.Index] = &Pack;
797
798 if (PartialPackDepthIndex ==
799 std::make_pair(Info.getDeducedDepth(), Pack.Index)) {
800 Pack.New.append(PartialPackArgs, PartialPackArgs + NumPartialPackArgs);
801 // We pre-populate the deduced value of the partially-substituted
802 // pack with the specified value. This is not entirely correct: the
803 // value is supposed to have been substituted, not deduced, but the
804 // cases where this is observable require an exact type match anyway.
805 //
806 // FIXME: If we could represent a "depth i, index j, pack elem k"
807 // parameter, we could substitute the partially-substituted pack
808 // everywhere and avoid this.
809 if (!IsPartiallyExpanded)
810 Deduced[Pack.Index] = Pack.New[PackElements];
811 }
812 }
813 }
814
815public:
816 ~PackDeductionScope() {
817 for (auto &Pack : Packs)
818 Info.PendingDeducedPacks[Pack.Index] = Pack.Outer;
819 }
820
821 /// Determine whether this pack has already been partially expanded into a
822 /// sequence of (prior) function parameters / template arguments.
823 bool isPartiallyExpanded() { return IsPartiallyExpanded; }
824
825 /// Determine whether this pack expansion scope has a known, fixed arity.
826 /// This happens if it involves a pack from an outer template that has
827 /// (notionally) already been expanded.
828 bool hasFixedArity() { return FixedNumExpansions.hasValue(); }
829
830 /// Determine whether the next element of the argument is still part of this
831 /// pack. This is the case unless the pack is already expanded to a fixed
832 /// length.
833 bool hasNextElement() {
834 return !FixedNumExpansions || *FixedNumExpansions > PackElements;
835 }
836
837 /// Move to deducing the next element in each pack that is being deduced.
838 void nextPackElement() {
839 // Capture the deduced template arguments for each parameter pack expanded
840 // by this pack expansion, add them to the list of arguments we've deduced
841 // for that pack, then clear out the deduced argument.
842 for (auto &Pack : Packs) {
843 DeducedTemplateArgument &DeducedArg = Deduced[Pack.Index];
844 if (!Pack.New.empty() || !DeducedArg.isNull()) {
845 while (Pack.New.size() < PackElements)
846 Pack.New.push_back(DeducedTemplateArgument());
847 if (Pack.New.size() == PackElements)
848 Pack.New.push_back(DeducedArg);
849 else
850 Pack.New[PackElements] = DeducedArg;
851 DeducedArg = Pack.New.size() > PackElements + 1
852 ? Pack.New[PackElements + 1]
853 : DeducedTemplateArgument();
854 }
855 }
856 ++PackElements;
857 }
858
859 /// Finish template argument deduction for a set of argument packs,
860 /// producing the argument packs and checking for consistency with prior
861 /// deductions.
862 Sema::TemplateDeductionResult
863 finish(bool TreatNoDeductionsAsNonDeduced = true) {
864 // Build argument packs for each of the parameter packs expanded by this
865 // pack expansion.
866 for (auto &Pack : Packs) {
867 // Put back the old value for this pack.
868 Deduced[Pack.Index] = Pack.Saved;
869
870 // If we are deducing the size of this pack even if we didn't deduce any
871 // values for it, then make sure we build a pack of the right size.
872 // FIXME: Should we always deduce the size, even if the pack appears in
873 // a non-deduced context?
874 if (!TreatNoDeductionsAsNonDeduced)
875 Pack.New.resize(PackElements);
876
877 // Build or find a new value for this pack.
878 DeducedTemplateArgument NewPack;
879 if (PackElements && Pack.New.empty()) {
880 if (Pack.DeferredDeduction.isNull()) {
881 // We were not able to deduce anything for this parameter pack
882 // (because it only appeared in non-deduced contexts), so just
883 // restore the saved argument pack.
884 continue;
885 }
886
887 NewPack = Pack.DeferredDeduction;
888 Pack.DeferredDeduction = TemplateArgument();
889 } else if (Pack.New.empty()) {
890 // If we deduced an empty argument pack, create it now.
891 NewPack = DeducedTemplateArgument(TemplateArgument::getEmptyPack());
892 } else {
893 TemplateArgument *ArgumentPack =
894 new (S.Context) TemplateArgument[Pack.New.size()];
895 std::copy(Pack.New.begin(), Pack.New.end(), ArgumentPack);
896 NewPack = DeducedTemplateArgument(
897 TemplateArgument(llvm::makeArrayRef(ArgumentPack, Pack.New.size())),
898 // FIXME: This is wrong, it's possible that some pack elements are
899 // deduced from an array bound and others are not:
900 // template<typename ...T, T ...V> void g(const T (&...p)[V]);
901 // g({1, 2, 3}, {{}, {}});
902 // ... should deduce T = {int, size_t (from array bound)}.
903 Pack.New[0].wasDeducedFromArrayBound());
904 }
905
906 // Pick where we're going to put the merged pack.
907 DeducedTemplateArgument *Loc;
908 if (Pack.Outer) {
909 if (Pack.Outer->DeferredDeduction.isNull()) {
910 // Defer checking this pack until we have a complete pack to compare
911 // it against.
912 Pack.Outer->DeferredDeduction = NewPack;
913 continue;
914 }
915 Loc = &Pack.Outer->DeferredDeduction;
916 } else {
917 Loc = &Deduced[Pack.Index];
918 }
919
920 // Check the new pack matches any previous value.
921 DeducedTemplateArgument OldPack = *Loc;
922 DeducedTemplateArgument Result =
923 checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
924
925 // If we deferred a deduction of this pack, check that one now too.
926 if (!Result.isNull() && !Pack.DeferredDeduction.isNull()) {
927 OldPack = Result;
928 NewPack = Pack.DeferredDeduction;
929 Result = checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
930 }
931
932 NamedDecl *Param = TemplateParams->getParam(Pack.Index);
933 if (Result.isNull()) {
934 Info.Param = makeTemplateParameter(Param);
935 Info.FirstArg = OldPack;
936 Info.SecondArg = NewPack;
937 return Sema::TDK_Inconsistent;
938 }
939
940 // If we have a pre-expanded pack and we didn't deduce enough elements
941 // for it, fail deduction.
942 if (Optional<unsigned> Expansions = getExpandedPackSize(Param)) {
943 if (*Expansions != PackElements) {
944 Info.Param = makeTemplateParameter(Param);
945 Info.FirstArg = Result;
946 return Sema::TDK_IncompletePack;
947 }
948 }
949
950 *Loc = Result;
951 }
952
953 return Sema::TDK_Success;
954 }
955
956private:
957 Sema &S;
958 TemplateParameterList *TemplateParams;
959 SmallVectorImpl<DeducedTemplateArgument> &Deduced;
960 TemplateDeductionInfo &Info;
961 unsigned PackElements = 0;
962 bool IsPartiallyExpanded = false;
963 /// The number of expansions, if we have a fully-expanded pack in this scope.
964 Optional<unsigned> FixedNumExpansions;
965
966 SmallVector<DeducedPack, 2> Packs;
967};
968
969} // namespace
970
971/// Deduce the template arguments by comparing the list of parameter
972/// types to the list of argument types, as in the parameter-type-lists of
973/// function types (C++ [temp.deduct.type]p10).
974///
975/// \param S The semantic analysis object within which we are deducing
976///
977/// \param TemplateParams The template parameters that we are deducing
978///
979/// \param Params The list of parameter types
980///
981/// \param NumParams The number of types in \c Params
982///
983/// \param Args The list of argument types
984///
985/// \param NumArgs The number of types in \c Args
986///
987/// \param Info information about the template argument deduction itself
988///
989/// \param Deduced the deduced template arguments
990///
991/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
992/// how template argument deduction is performed.
993///
994/// \param PartialOrdering If true, we are performing template argument
995/// deduction for during partial ordering for a call
996/// (C++0x [temp.deduct.partial]).
997///
998/// \returns the result of template argument deduction so far. Note that a
999/// "success" result means that template argument deduction has not yet failed,
1000/// but it may still fail, later, for other reasons.
1001static Sema::TemplateDeductionResult
1002DeduceTemplateArguments(Sema &S,
1003 TemplateParameterList *TemplateParams,
1004 const QualType *Params, unsigned NumParams,
1005 const QualType *Args, unsigned NumArgs,
1006 TemplateDeductionInfo &Info,
1007 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1008 unsigned TDF,
1009 bool PartialOrdering = false) {
1010 // C++0x [temp.deduct.type]p10:
1011 // Similarly, if P has a form that contains (T), then each parameter type
1012 // Pi of the respective parameter-type- list of P is compared with the
1013 // corresponding parameter type Ai of the corresponding parameter-type-list
1014 // of A. [...]
1015 unsigned ArgIdx = 0, ParamIdx = 0;
1016 for (; ParamIdx != NumParams; ++ParamIdx) {
1017 // Check argument types.
1018 const PackExpansionType *Expansion
1019 = dyn_cast<PackExpansionType>(Params[ParamIdx]);
1020 if (!Expansion) {
1021 // Simple case: compare the parameter and argument types at this point.
1022
1023 // Make sure we have an argument.
1024 if (ArgIdx >= NumArgs)
1025 return Sema::TDK_MiscellaneousDeductionFailure;
1026
1027 if (isa<PackExpansionType>(Args[ArgIdx])) {
1028 // C++0x [temp.deduct.type]p22:
1029 // If the original function parameter associated with A is a function
1030 // parameter pack and the function parameter associated with P is not
1031 // a function parameter pack, then template argument deduction fails.
1032 return Sema::TDK_MiscellaneousDeductionFailure;
1033 }
1034
1035 if (Sema::TemplateDeductionResult Result
1036 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1037 Params[ParamIdx], Args[ArgIdx],
1038 Info, Deduced, TDF,
1039 PartialOrdering))
1040 return Result;
1041
1042 ++ArgIdx;
1043 continue;
1044 }
1045
1046 // C++0x [temp.deduct.type]p10:
1047 // If the parameter-declaration corresponding to Pi is a function
1048 // parameter pack, then the type of its declarator- id is compared with
1049 // each remaining parameter type in the parameter-type-list of A. Each
1050 // comparison deduces template arguments for subsequent positions in the
1051 // template parameter packs expanded by the function parameter pack.
1052
1053 QualType Pattern = Expansion->getPattern();
1054 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
1055
1056 // A pack scope with fixed arity is not really a pack any more, so is not
1057 // a non-deduced context.
1058 if (ParamIdx + 1 == NumParams || PackScope.hasFixedArity()) {
1059 for (; ArgIdx < NumArgs && PackScope.hasNextElement(); ++ArgIdx) {
1060 // Deduce template arguments from the pattern.
1061 if (Sema::TemplateDeductionResult Result
1062 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern,
1063 Args[ArgIdx], Info, Deduced,
1064 TDF, PartialOrdering))
1065 return Result;
1066
1067 PackScope.nextPackElement();
1068 }
1069 } else {
1070 // C++0x [temp.deduct.type]p5:
1071 // The non-deduced contexts are:
1072 // - A function parameter pack that does not occur at the end of the
1073 // parameter-declaration-clause.
1074 //
1075 // FIXME: There is no wording to say what we should do in this case. We
1076 // choose to resolve this by applying the same rule that is applied for a
1077 // function call: that is, deduce all contained packs to their
1078 // explicitly-specified values (or to <> if there is no such value).
1079 //
1080 // This is seemingly-arbitrarily different from the case of a template-id
1081 // with a non-trailing pack-expansion in its arguments, which renders the
1082 // entire template-argument-list a non-deduced context.
1083
1084 // If the parameter type contains an explicitly-specified pack that we
1085 // could not expand, skip the number of parameters notionally created
1086 // by the expansion.
1087 Optional<unsigned> NumExpansions = Expansion->getNumExpansions();
1088 if (NumExpansions && !PackScope.isPartiallyExpanded()) {
1089 for (unsigned I = 0; I != *NumExpansions && ArgIdx < NumArgs;
1090 ++I, ++ArgIdx)
1091 PackScope.nextPackElement();
1092 }
1093 }
1094
1095 // Build argument packs for each of the parameter packs expanded by this
1096 // pack expansion.
1097 if (auto Result = PackScope.finish())
1098 return Result;
1099 }
1100
1101 // Make sure we don't have any extra arguments.
1102 if (ArgIdx < NumArgs)
1103 return Sema::TDK_MiscellaneousDeductionFailure;
1104
1105 return Sema::TDK_Success;
1106}
1107
1108/// Determine whether the parameter has qualifiers that the argument
1109/// lacks. Put another way, determine whether there is no way to add
1110/// a deduced set of qualifiers to the ParamType that would result in
1111/// its qualifiers matching those of the ArgType.
1112static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType,
1113 QualType ArgType) {
1114 Qualifiers ParamQs = ParamType.getQualifiers();
1115 Qualifiers ArgQs = ArgType.getQualifiers();
1116
1117 if (ParamQs == ArgQs)
1118 return false;
1119
1120 // Mismatched (but not missing) Objective-C GC attributes.
1121 if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() &&
1122 ParamQs.hasObjCGCAttr())
1123 return true;
1124
1125 // Mismatched (but not missing) address spaces.
1126 if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() &&
1127 ParamQs.hasAddressSpace())
1128 return true;
1129
1130 // Mismatched (but not missing) Objective-C lifetime qualifiers.
1131 if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() &&
1132 ParamQs.hasObjCLifetime())
1133 return true;
1134
1135 // CVR qualifiers inconsistent or a superset.
1136 return (ParamQs.getCVRQualifiers() & ~ArgQs.getCVRQualifiers()) != 0;
1137}
1138
1139/// Compare types for equality with respect to possibly compatible
1140/// function types (noreturn adjustment, implicit calling conventions). If any
1141/// of parameter and argument is not a function, just perform type comparison.
1142///
1143/// \param Param the template parameter type.
1144///
1145/// \param Arg the argument type.
1146bool Sema::isSameOrCompatibleFunctionType(CanQualType Param,
1147 CanQualType Arg) {
1148 const FunctionType *ParamFunction = Param->getAs<FunctionType>(),
1149 *ArgFunction = Arg->getAs<FunctionType>();
1150
1151 // Just compare if not functions.
1152 if (!ParamFunction || !ArgFunction)
1153 return Param == Arg;
1154
1155 // Noreturn and noexcept adjustment.
1156 QualType AdjustedParam;
1157 if (IsFunctionConversion(Param, Arg, AdjustedParam))
1158 return Arg == Context.getCanonicalType(AdjustedParam);
1159
1160 // FIXME: Compatible calling conventions.
1161
1162 return Param == Arg;
1163}
1164
1165/// Get the index of the first template parameter that was originally from the
1166/// innermost template-parameter-list. This is 0 except when we concatenate
1167/// the template parameter lists of a class template and a constructor template
1168/// when forming an implicit deduction guide.
1169static unsigned getFirstInnerIndex(FunctionTemplateDecl *FTD) {
1170 auto *Guide = dyn_cast<CXXDeductionGuideDecl>(FTD->getTemplatedDecl());
1171 if (!Guide || !Guide->isImplicit())
1172 return 0;
1173 return Guide->getDeducedTemplate()->getTemplateParameters()->size();
1174}
1175
1176/// Determine whether a type denotes a forwarding reference.
1177static bool isForwardingReference(QualType Param, unsigned FirstInnerIndex) {
1178 // C++1z [temp.deduct.call]p3:
1179 // A forwarding reference is an rvalue reference to a cv-unqualified
1180 // template parameter that does not represent a template parameter of a
1181 // class template.
1182 if (auto *ParamRef = Param->getAs<RValueReferenceType>()) {
1183 if (ParamRef->getPointeeType().getQualifiers())
1184 return false;
1185 auto *TypeParm = ParamRef->getPointeeType()->getAs<TemplateTypeParmType>();
1186 return TypeParm && TypeParm->getIndex() >= FirstInnerIndex;
1187 }
1188 return false;
1189}
1190
1191/// Deduce the template arguments by comparing the parameter type and
1192/// the argument type (C++ [temp.deduct.type]).
1193///
1194/// \param S the semantic analysis object within which we are deducing
1195///
1196/// \param TemplateParams the template parameters that we are deducing
1197///
1198/// \param ParamIn the parameter type
1199///
1200/// \param ArgIn the argument type
1201///
1202/// \param Info information about the template argument deduction itself
1203///
1204/// \param Deduced the deduced template arguments
1205///
1206/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
1207/// how template argument deduction is performed.
1208///
1209/// \param PartialOrdering Whether we're performing template argument deduction
1210/// in the context of partial ordering (C++0x [temp.deduct.partial]).
1211///
1212/// \returns the result of template argument deduction so far. Note that a
1213/// "success" result means that template argument deduction has not yet failed,
1214/// but it may still fail, later, for other reasons.
1215static Sema::TemplateDeductionResult
1216DeduceTemplateArgumentsByTypeMatch(Sema &S,
1217 TemplateParameterList *TemplateParams,
1218 QualType ParamIn, QualType ArgIn,
1219 TemplateDeductionInfo &Info,
1220 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1221 unsigned TDF,
1222 bool PartialOrdering,
1223 bool DeducedFromArrayBound) {
1224 // We only want to look at the canonical types, since typedefs and
1225 // sugar are not part of template argument deduction.
1226 QualType Param = S.Context.getCanonicalType(ParamIn);
1227 QualType Arg = S.Context.getCanonicalType(ArgIn);
1228
1229 // If the argument type is a pack expansion, look at its pattern.
1230 // This isn't explicitly called out
1231 if (const PackExpansionType *ArgExpansion
1232 = dyn_cast<PackExpansionType>(Arg))
1233 Arg = ArgExpansion->getPattern();
1234
1235 if (PartialOrdering) {
1236 // C++11 [temp.deduct.partial]p5:
1237 // Before the partial ordering is done, certain transformations are
1238 // performed on the types used for partial ordering:
1239 // - If P is a reference type, P is replaced by the type referred to.
1240 const ReferenceType *ParamRef = Param->getAs<ReferenceType>();
1241 if (ParamRef)
1242 Param = ParamRef->getPointeeType();
1243
1244 // - If A is a reference type, A is replaced by the type referred to.
1245 const ReferenceType *ArgRef = Arg->getAs<ReferenceType>();
1246 if (ArgRef)
1247 Arg = ArgRef->getPointeeType();
1248
1249 if (ParamRef && ArgRef && S.Context.hasSameUnqualifiedType(Param, Arg)) {
1250 // C++11 [temp.deduct.partial]p9:
1251 // If, for a given type, deduction succeeds in both directions (i.e.,
1252 // the types are identical after the transformations above) and both
1253 // P and A were reference types [...]:
1254 // - if [one type] was an lvalue reference and [the other type] was
1255 // not, [the other type] is not considered to be at least as
1256 // specialized as [the first type]
1257 // - if [one type] is more cv-qualified than [the other type],
1258 // [the other type] is not considered to be at least as specialized
1259 // as [the first type]
1260 // Objective-C ARC adds:
1261 // - [one type] has non-trivial lifetime, [the other type] has
1262 // __unsafe_unretained lifetime, and the types are otherwise
1263 // identical
1264 //
1265 // A is "considered to be at least as specialized" as P iff deduction
1266 // succeeds, so we model this as a deduction failure. Note that
1267 // [the first type] is P and [the other type] is A here; the standard
1268 // gets this backwards.
1269 Qualifiers ParamQuals = Param.getQualifiers();
1270 Qualifiers ArgQuals = Arg.getQualifiers();
1271 if ((ParamRef->isLValueReferenceType() &&
1272 !ArgRef->isLValueReferenceType()) ||
1273 ParamQuals.isStrictSupersetOf(ArgQuals) ||
1274 (ParamQuals.hasNonTrivialObjCLifetime() &&
1275 ArgQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
1276 ParamQuals.withoutObjCLifetime() ==
1277 ArgQuals.withoutObjCLifetime())) {
1278 Info.FirstArg = TemplateArgument(ParamIn);
1279 Info.SecondArg = TemplateArgument(ArgIn);
1280 return Sema::TDK_NonDeducedMismatch;
1281 }
1282 }
1283
1284 // C++11 [temp.deduct.partial]p7:
1285 // Remove any top-level cv-qualifiers:
1286 // - If P is a cv-qualified type, P is replaced by the cv-unqualified
1287 // version of P.
1288 Param = Param.getUnqualifiedType();
1289 // - If A is a cv-qualified type, A is replaced by the cv-unqualified
1290 // version of A.
1291 Arg = Arg.getUnqualifiedType();
1292 } else {
1293 // C++0x [temp.deduct.call]p4 bullet 1:
1294 // - If the original P is a reference type, the deduced A (i.e., the type
1295 // referred to by the reference) can be more cv-qualified than the
1296 // transformed A.
1297 if (TDF & TDF_ParamWithReferenceType) {
1298 Qualifiers Quals;
1299 QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals);
1300 Quals.setCVRQualifiers(Quals.getCVRQualifiers() &
1301 Arg.getCVRQualifiers());
1302 Param = S.Context.getQualifiedType(UnqualParam, Quals);
1303 }
1304
1305 if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
1306 // C++0x [temp.deduct.type]p10:
1307 // If P and A are function types that originated from deduction when
1308 // taking the address of a function template (14.8.2.2) or when deducing
1309 // template arguments from a function declaration (14.8.2.6) and Pi and
1310 // Ai are parameters of the top-level parameter-type-list of P and A,
1311 // respectively, Pi is adjusted if it is a forwarding reference and Ai
1312 // is an lvalue reference, in
1313 // which case the type of Pi is changed to be the template parameter
1314 // type (i.e., T&& is changed to simply T). [ Note: As a result, when
1315 // Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be
1316 // deduced as X&. - end note ]
1317 TDF &= ~TDF_TopLevelParameterTypeList;
1318 if (isForwardingReference(Param, 0) && Arg->isLValueReferenceType())
1319 Param = Param->getPointeeType();
1320 }
1321 }
1322
1323 // C++ [temp.deduct.type]p9:
1324 // A template type argument T, a template template argument TT or a
1325 // template non-type argument i can be deduced if P and A have one of
1326 // the following forms:
1327 //
1328 // T
1329 // cv-list T
1330 if (const TemplateTypeParmType *TemplateTypeParm
1331 = Param->getAs<TemplateTypeParmType>()) {
1332 // Just skip any attempts to deduce from a placeholder type or a parameter
1333 // at a different depth.
1334 if (Arg->isPlaceholderType() ||
1335 Info.getDeducedDepth() != TemplateTypeParm->getDepth())
1336 return Sema::TDK_Success;
1337
1338 unsigned Index = TemplateTypeParm->getIndex();
1339 bool RecanonicalizeArg = false;
1340
1341 // If the argument type is an array type, move the qualifiers up to the
1342 // top level, so they can be matched with the qualifiers on the parameter.
1343 if (isa<ArrayType>(Arg)) {
1344 Qualifiers Quals;
1345 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
1346 if (Quals) {
1347 Arg = S.Context.getQualifiedType(Arg, Quals);
1348 RecanonicalizeArg = true;
1349 }
1350 }
1351
1352 // The argument type can not be less qualified than the parameter
1353 // type.
1354 if (!(TDF & TDF_IgnoreQualifiers) &&
1355 hasInconsistentOrSupersetQualifiersOf(Param, Arg)) {
1356 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1357 Info.FirstArg = TemplateArgument(Param);
1358 Info.SecondArg = TemplateArgument(Arg);
1359 return Sema::TDK_Underqualified;
1360 }
1361
1362 // Do not match a function type with a cv-qualified type.
1363 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1584
1364 if (Arg->isFunctionType() && Param.hasQualifiers()) {
1365 return Sema::TDK_NonDeducedMismatch;
1366 }
1367
1368 assert(TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&((TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&
"saw template type parameter with wrong depth") ? static_cast
<void> (0) : __assert_fail ("TemplateTypeParm->getDepth() == Info.getDeducedDepth() && \"saw template type parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1369, __PRETTY_FUNCTION__))
1369 "saw template type parameter with wrong depth")((TemplateTypeParm->getDepth() == Info.getDeducedDepth() &&
"saw template type parameter with wrong depth") ? static_cast
<void> (0) : __assert_fail ("TemplateTypeParm->getDepth() == Info.getDeducedDepth() && \"saw template type parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1369, __PRETTY_FUNCTION__))
;
1370 assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function")((Arg != S.Context.OverloadTy && "Unresolved overloaded function"
) ? static_cast<void> (0) : __assert_fail ("Arg != S.Context.OverloadTy && \"Unresolved overloaded function\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1370, __PRETTY_FUNCTION__))
;
1371 QualType DeducedType = Arg;
1372
1373 // Remove any qualifiers on the parameter from the deduced type.
1374 // We checked the qualifiers for consistency above.
1375 Qualifiers DeducedQs = DeducedType.getQualifiers();
1376 Qualifiers ParamQs = Param.getQualifiers();
1377 DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers());
1378 if (ParamQs.hasObjCGCAttr())
1379 DeducedQs.removeObjCGCAttr();
1380 if (ParamQs.hasAddressSpace())
1381 DeducedQs.removeAddressSpace();
1382 if (ParamQs.hasObjCLifetime())
1383 DeducedQs.removeObjCLifetime();
1384
1385 // Objective-C ARC:
1386 // If template deduction would produce a lifetime qualifier on a type
1387 // that is not a lifetime type, template argument deduction fails.
1388 if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() &&
1389 !DeducedType->isDependentType()) {
1390 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1391 Info.FirstArg = TemplateArgument(Param);
1392 Info.SecondArg = TemplateArgument(Arg);
1393 return Sema::TDK_Underqualified;
1394 }
1395
1396 // Objective-C ARC:
1397 // If template deduction would produce an argument type with lifetime type
1398 // but no lifetime qualifier, the __strong lifetime qualifier is inferred.
1399 if (S.getLangOpts().ObjCAutoRefCount &&
1400 DeducedType->isObjCLifetimeType() &&
1401 !DeducedQs.hasObjCLifetime())
1402 DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong);
1403
1404 DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(),
1405 DeducedQs);
1406
1407 if (RecanonicalizeArg)
1408 DeducedType = S.Context.getCanonicalType(DeducedType);
1409
1410 DeducedTemplateArgument NewDeduced(DeducedType, DeducedFromArrayBound);
1411 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
1412 Deduced[Index],
1413 NewDeduced);
1414 if (Result.isNull()) {
1415 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1416 Info.FirstArg = Deduced[Index];
1417 Info.SecondArg = NewDeduced;
1418 return Sema::TDK_Inconsistent;
1419 }
1420
1421 Deduced[Index] = Result;
1422 return Sema::TDK_Success;
1423 }
1424
1425 // Set up the template argument deduction information for a failure.
1426 Info.FirstArg = TemplateArgument(ParamIn);
1427 Info.SecondArg = TemplateArgument(ArgIn);
1428
1429 // If the parameter is an already-substituted template parameter
1430 // pack, do nothing: we don't know which of its arguments to look
1431 // at, so we have to wait until all of the parameter packs in this
1432 // expansion have arguments.
1433 if (isa<SubstTemplateTypeParmPackType>(Param))
1434 return Sema::TDK_Success;
1435
1436 // Check the cv-qualifiers on the parameter and argument types.
1437 CanQualType CanParam = S.Context.getCanonicalType(Param);
1438 CanQualType CanArg = S.Context.getCanonicalType(Arg);
1439 if (!(TDF & TDF_IgnoreQualifiers)) {
1440 if (TDF & TDF_ParamWithReferenceType) {
1441 if (hasInconsistentOrSupersetQualifiersOf(Param, Arg))
1442 return Sema::TDK_NonDeducedMismatch;
1443 } else if (TDF & TDF_ArgWithReferenceType) {
1444 // C++ [temp.deduct.conv]p4:
1445 // If the original A is a reference type, A can be more cv-qualified
1446 // than the deduced A
1447 if (!Arg.getQualifiers().compatiblyIncludes(Param.getQualifiers()))
1448 return Sema::TDK_NonDeducedMismatch;
1449
1450 // Strip out all extra qualifiers from the argument to figure out the
1451 // type we're converting to, prior to the qualification conversion.
1452 Qualifiers Quals;
1453 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
1454 Arg = S.Context.getQualifiedType(Arg, Param.getQualifiers());
1455 } else if (!IsPossiblyOpaquelyQualifiedType(Param)) {
1456 if (Param.getCVRQualifiers() != Arg.getCVRQualifiers())
1457 return Sema::TDK_NonDeducedMismatch;
1458 }
1459
1460 // If the parameter type is not dependent, there is nothing to deduce.
1461 if (!Param->isDependentType()) {
1462 if (!(TDF & TDF_SkipNonDependent)) {
1463 bool NonDeduced =
1464 (TDF & TDF_AllowCompatibleFunctionType)
1465 ? !S.isSameOrCompatibleFunctionType(CanParam, CanArg)
1466 : Param != Arg;
1467 if (NonDeduced) {
1468 return Sema::TDK_NonDeducedMismatch;
1469 }
1470 }
1471 return Sema::TDK_Success;
1472 }
1473 } else if (!Param->isDependentType()) {
1474 CanQualType ParamUnqualType = CanParam.getUnqualifiedType(),
1475 ArgUnqualType = CanArg.getUnqualifiedType();
1476 bool Success =
1477 (TDF & TDF_AllowCompatibleFunctionType)
1478 ? S.isSameOrCompatibleFunctionType(ParamUnqualType, ArgUnqualType)
1479 : ParamUnqualType == ArgUnqualType;
1480 if (Success)
1481 return Sema::TDK_Success;
1482 }
1483
1484 switch (Param->getTypeClass()) {
1485 // Non-canonical types cannot appear here.
1486#define NON_CANONICAL_TYPE(Class, Base) \
1487 case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class)::llvm::llvm_unreachable_internal("deducing non-canonical type: "
#Class, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1487)
;
1488#define TYPE(Class, Base)
1489#include "clang/AST/TypeNodes.inc"
1490
1491 case Type::TemplateTypeParm:
1492 case Type::SubstTemplateTypeParmPack:
1493 llvm_unreachable("Type nodes handled above")::llvm::llvm_unreachable_internal("Type nodes handled above",
"/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1493)
;
1494
1495 // These types cannot be dependent, so simply check whether the types are
1496 // the same.
1497 case Type::Builtin:
1498 case Type::VariableArray:
1499 case Type::Vector:
1500 case Type::FunctionNoProto:
1501 case Type::Record:
1502 case Type::Enum:
1503 case Type::ObjCObject:
1504 case Type::ObjCInterface:
1505 case Type::ObjCObjectPointer:
1506 if (TDF & TDF_SkipNonDependent)
1507 return Sema::TDK_Success;
1508
1509 if (TDF & TDF_IgnoreQualifiers) {
1510 Param = Param.getUnqualifiedType();
1511 Arg = Arg.getUnqualifiedType();
1512 }
1513
1514 return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch;
1515
1516 // _Complex T [placeholder extension]
1517 case Type::Complex:
1518 if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>())
1519 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1520 cast<ComplexType>(Param)->getElementType(),
1521 ComplexArg->getElementType(),
1522 Info, Deduced, TDF);
1523
1524 return Sema::TDK_NonDeducedMismatch;
1525
1526 // _Atomic T [extension]
1527 case Type::Atomic:
1528 if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>())
1529 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1530 cast<AtomicType>(Param)->getValueType(),
1531 AtomicArg->getValueType(),
1532 Info, Deduced, TDF);
1533
1534 return Sema::TDK_NonDeducedMismatch;
1535
1536 // T *
1537 case Type::Pointer: {
1538 QualType PointeeType;
1539 if (const PointerType *PointerArg = Arg->getAs<PointerType>()) {
1540 PointeeType = PointerArg->getPointeeType();
1541 } else if (const ObjCObjectPointerType *PointerArg
1542 = Arg->getAs<ObjCObjectPointerType>()) {
1543 PointeeType = PointerArg->getPointeeType();
1544 } else {
1545 return Sema::TDK_NonDeducedMismatch;
1546 }
1547
1548 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass);
1549 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1550 cast<PointerType>(Param)->getPointeeType(),
1551 PointeeType,
1552 Info, Deduced, SubTDF);
1553 }
1554
1555 // T &
1556 case Type::LValueReference: {
1557 const LValueReferenceType *ReferenceArg =
1558 Arg->getAs<LValueReferenceType>();
1559 if (!ReferenceArg)
1560 return Sema::TDK_NonDeducedMismatch;
1561
1562 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1563 cast<LValueReferenceType>(Param)->getPointeeType(),
1564 ReferenceArg->getPointeeType(), Info, Deduced, 0);
1565 }
1566
1567 // T && [C++0x]
1568 case Type::RValueReference: {
1569 const RValueReferenceType *ReferenceArg =
1570 Arg->getAs<RValueReferenceType>();
1571 if (!ReferenceArg)
1572 return Sema::TDK_NonDeducedMismatch;
1573
1574 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1575 cast<RValueReferenceType>(Param)->getPointeeType(),
1576 ReferenceArg->getPointeeType(),
1577 Info, Deduced, 0);
1578 }
1579
1580 // T [] (implied, but not stated explicitly)
1581 case Type::IncompleteArray: {
1582 const IncompleteArrayType *IncompleteArrayArg =
1583 S.Context.getAsIncompleteArrayType(Arg);
1584 if (!IncompleteArrayArg)
1585 return Sema::TDK_NonDeducedMismatch;
1586
1587 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1588 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1589 S.Context.getAsIncompleteArrayType(Param)->getElementType(),
1590 IncompleteArrayArg->getElementType(),
1591 Info, Deduced, SubTDF);
1592 }
1593
1594 // T [integer-constant]
1595 case Type::ConstantArray: {
1596 const ConstantArrayType *ConstantArrayArg =
1597 S.Context.getAsConstantArrayType(Arg);
1598 if (!ConstantArrayArg)
1599 return Sema::TDK_NonDeducedMismatch;
1600
1601 const ConstantArrayType *ConstantArrayParm =
1602 S.Context.getAsConstantArrayType(Param);
1603 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize())
1604 return Sema::TDK_NonDeducedMismatch;
1605
1606 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1607 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1608 ConstantArrayParm->getElementType(),
1609 ConstantArrayArg->getElementType(),
1610 Info, Deduced, SubTDF);
1611 }
1612
1613 // type [i]
1614 case Type::DependentSizedArray: {
1615 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg);
1616 if (!ArrayArg)
1617 return Sema::TDK_NonDeducedMismatch;
1618
1619 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1620
1621 // Check the element type of the arrays
1622 const DependentSizedArrayType *DependentArrayParm
1623 = S.Context.getAsDependentSizedArrayType(Param);
1624 if (Sema::TemplateDeductionResult Result
1625 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1626 DependentArrayParm->getElementType(),
1627 ArrayArg->getElementType(),
1628 Info, Deduced, SubTDF))
1629 return Result;
1630
1631 // Determine the array bound is something we can deduce.
1632 NonTypeTemplateParmDecl *NTTP
1633 = getDeducedParameterFromExpr(Info, DependentArrayParm->getSizeExpr());
1634 if (!NTTP)
1635 return Sema::TDK_Success;
1636
1637 // We can perform template argument deduction for the given non-type
1638 // template parameter.
1639 assert(NTTP->getDepth() == Info.getDeducedDepth() &&((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1640, __PRETTY_FUNCTION__))
1640 "saw non-type template parameter with wrong depth")((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1640, __PRETTY_FUNCTION__))
;
1641 if (const ConstantArrayType *ConstantArrayArg
1642 = dyn_cast<ConstantArrayType>(ArrayArg)) {
1643 llvm::APSInt Size(ConstantArrayArg->getSize());
1644 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, Size,
1645 S.Context.getSizeType(),
1646 /*ArrayBound=*/true,
1647 Info, Deduced);
1648 }
1649 if (const DependentSizedArrayType *DependentArrayArg
1650 = dyn_cast<DependentSizedArrayType>(ArrayArg))
1651 if (DependentArrayArg->getSizeExpr())
1652 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
1653 DependentArrayArg->getSizeExpr(),
1654 Info, Deduced);
1655
1656 // Incomplete type does not match a dependently-sized array type
1657 return Sema::TDK_NonDeducedMismatch;
1658 }
1659
1660 // type(*)(T)
1661 // T(*)()
1662 // T(*)(T)
1663 case Type::FunctionProto: {
1664 unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList;
1665 const FunctionProtoType *FunctionProtoArg =
1666 dyn_cast<FunctionProtoType>(Arg);
1667 if (!FunctionProtoArg)
1668 return Sema::TDK_NonDeducedMismatch;
1669
1670 const FunctionProtoType *FunctionProtoParam =
1671 cast<FunctionProtoType>(Param);
1672
1673 if (FunctionProtoParam->getMethodQuals()
1674 != FunctionProtoArg->getMethodQuals() ||
1675 FunctionProtoParam->getRefQualifier()
1676 != FunctionProtoArg->getRefQualifier() ||
1677 FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
1678 return Sema::TDK_NonDeducedMismatch;
1679
1680 // Check return types.
1681 if (auto Result = DeduceTemplateArgumentsByTypeMatch(
1682 S, TemplateParams, FunctionProtoParam->getReturnType(),
1683 FunctionProtoArg->getReturnType(), Info, Deduced, 0))
1684 return Result;
1685
1686 // Check parameter types.
1687 if (auto Result = DeduceTemplateArguments(
1688 S, TemplateParams, FunctionProtoParam->param_type_begin(),
1689 FunctionProtoParam->getNumParams(),
1690 FunctionProtoArg->param_type_begin(),
1691 FunctionProtoArg->getNumParams(), Info, Deduced, SubTDF))
1692 return Result;
1693
1694 if (TDF & TDF_AllowCompatibleFunctionType)
1695 return Sema::TDK_Success;
1696
1697 // FIXME: Per core-2016/10/1019 (no corresponding core issue yet), permit
1698 // deducing through the noexcept-specifier if it's part of the canonical
1699 // type. libstdc++ relies on this.
1700 Expr *NoexceptExpr = FunctionProtoParam->getNoexceptExpr();
1701 if (NonTypeTemplateParmDecl *NTTP =
1702 NoexceptExpr ? getDeducedParameterFromExpr(Info, NoexceptExpr)
1703 : nullptr) {
1704 assert(NTTP->getDepth() == Info.getDeducedDepth() &&((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1705, __PRETTY_FUNCTION__))
1705 "saw non-type template parameter with wrong depth")((NTTP->getDepth() == Info.getDeducedDepth() && "saw non-type template parameter with wrong depth"
) ? static_cast<void> (0) : __assert_fail ("NTTP->getDepth() == Info.getDeducedDepth() && \"saw non-type template parameter with wrong depth\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1705, __PRETTY_FUNCTION__))
;
1706
1707 llvm::APSInt Noexcept(1);
1708 switch (FunctionProtoArg->canThrow()) {
1709 case CT_Cannot:
1710 Noexcept = 1;
1711 LLVM_FALLTHROUGH[[gnu::fallthrough]];
1712
1713 case CT_Can:
1714 // We give E in noexcept(E) the "deduced from array bound" treatment.
1715 // FIXME: Should we?
1716 return DeduceNonTypeTemplateArgument(
1717 S, TemplateParams, NTTP, Noexcept, S.Context.BoolTy,
1718 /*ArrayBound*/true, Info, Deduced);
1719
1720 case CT_Dependent:
1721 if (Expr *ArgNoexceptExpr = FunctionProtoArg->getNoexceptExpr())
1722 return DeduceNonTypeTemplateArgument(
1723 S, TemplateParams, NTTP, ArgNoexceptExpr, Info, Deduced);
1724 // Can't deduce anything from throw(T...).
1725 break;
1726 }
1727 }
1728 // FIXME: Detect non-deduced exception specification mismatches?
1729 //
1730 // Careful about [temp.deduct.call] and [temp.deduct.conv], which allow
1731 // top-level differences in noexcept-specifications.
1732
1733 return Sema::TDK_Success;
1734 }
1735
1736 case Type::InjectedClassName:
1737 // Treat a template's injected-class-name as if the template
1738 // specialization type had been used.
1739 Param = cast<InjectedClassNameType>(Param)
1740 ->getInjectedSpecializationType();
1741 assert(isa<TemplateSpecializationType>(Param) &&((isa<TemplateSpecializationType>(Param) && "injected class name is not a template specialization type"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateSpecializationType>(Param) && \"injected class name is not a template specialization type\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1742, __PRETTY_FUNCTION__))
1742 "injected class name is not a template specialization type")((isa<TemplateSpecializationType>(Param) && "injected class name is not a template specialization type"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateSpecializationType>(Param) && \"injected class name is not a template specialization type\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1742, __PRETTY_FUNCTION__))
;
1743 LLVM_FALLTHROUGH[[gnu::fallthrough]];
1744
1745 // template-name<T> (where template-name refers to a class template)
1746 // template-name<i>
1747 // TT<T>
1748 // TT<i>
1749 // TT<>
1750 case Type::TemplateSpecialization: {
1751 const TemplateSpecializationType *SpecParam =
1752 cast<TemplateSpecializationType>(Param);
1753
1754 // When Arg cannot be a derived class, we can just try to deduce template
1755 // arguments from the template-id.
1756 const RecordType *RecordT = Arg->getAs<RecordType>();
1757 if (!(TDF & TDF_DerivedClass) || !RecordT)
1758 return DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, Info,
1759 Deduced);
1760
1761 SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(),
1762 Deduced.end());
1763
1764 Sema::TemplateDeductionResult Result = DeduceTemplateArguments(
1765 S, TemplateParams, SpecParam, Arg, Info, Deduced);
1766
1767 if (Result == Sema::TDK_Success)
1768 return Result;
1769
1770 // We cannot inspect base classes as part of deduction when the type
1771 // is incomplete, so either instantiate any templates necessary to
1772 // complete the type, or skip over it if it cannot be completed.
1773 if (!S.isCompleteType(Info.getLocation(), Arg))
1774 return Result;
1775
1776 // C++14 [temp.deduct.call] p4b3:
1777 // If P is a class and P has the form simple-template-id, then the
1778 // transformed A can be a derived class of the deduced A. Likewise if
1779 // P is a pointer to a class of the form simple-template-id, the
1780 // transformed A can be a pointer to a derived class pointed to by the
1781 // deduced A.
1782 //
1783 // These alternatives are considered only if type deduction would
1784 // otherwise fail. If they yield more than one possible deduced A, the
1785 // type deduction fails.
1786
1787 // Reset the incorrectly deduced argument from above.
1788 Deduced = DeducedOrig;
1789
1790 // Use data recursion to crawl through the list of base classes.
1791 // Visited contains the set of nodes we have already visited, while
1792 // ToVisit is our stack of records that we still need to visit.
1793 llvm::SmallPtrSet<const RecordType *, 8> Visited;
1794 SmallVector<const RecordType *, 8> ToVisit;
1795 ToVisit.push_back(RecordT);
1796 bool Successful = false;
1797 SmallVector<DeducedTemplateArgument, 8> SuccessfulDeduced;
1798 while (!ToVisit.empty()) {
1799 // Retrieve the next class in the inheritance hierarchy.
1800 const RecordType *NextT = ToVisit.pop_back_val();
1801
1802 // If we have already seen this type, skip it.
1803 if (!Visited.insert(NextT).second)
1804 continue;
1805
1806 // If this is a base class, try to perform template argument
1807 // deduction from it.
1808 if (NextT != RecordT) {
1809 TemplateDeductionInfo BaseInfo(Info.getLocation());
1810 Sema::TemplateDeductionResult BaseResult =
1811 DeduceTemplateArguments(S, TemplateParams, SpecParam,
1812 QualType(NextT, 0), BaseInfo, Deduced);
1813
1814 // If template argument deduction for this base was successful,
1815 // note that we had some success. Otherwise, ignore any deductions
1816 // from this base class.
1817 if (BaseResult == Sema::TDK_Success) {
1818 // If we've already seen some success, then deduction fails due to
1819 // an ambiguity (temp.deduct.call p5).
1820 if (Successful)
1821 return Sema::TDK_MiscellaneousDeductionFailure;
1822
1823 Successful = true;
1824 std::swap(SuccessfulDeduced, Deduced);
1825
1826 Info.Param = BaseInfo.Param;
1827 Info.FirstArg = BaseInfo.FirstArg;
1828 Info.SecondArg = BaseInfo.SecondArg;
1829 }
1830
1831 Deduced = DeducedOrig;
1832 }
1833
1834 // Visit base classes
1835 CXXRecordDecl *Next = cast<CXXRecordDecl>(NextT->getDecl());
1836 for (const auto &Base : Next->bases()) {
1837 assert(Base.getType()->isRecordType() &&((Base.getType()->isRecordType() && "Base class that isn't a record?"
) ? static_cast<void> (0) : __assert_fail ("Base.getType()->isRecordType() && \"Base class that isn't a record?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1838, __PRETTY_FUNCTION__))
1838 "Base class that isn't a record?")((Base.getType()->isRecordType() && "Base class that isn't a record?"
) ? static_cast<void> (0) : __assert_fail ("Base.getType()->isRecordType() && \"Base class that isn't a record?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 1838, __PRETTY_FUNCTION__))
;
1839 ToVisit.push_back(Base.getType()->getAs<RecordType>());
1840 }
1841 }
1842
1843 if (Successful) {
1844 std::swap(SuccessfulDeduced, Deduced);
1845 return Sema::TDK_Success;
1846 }
1847
1848 return Result;
1849 }
1850
1851 // T type::*
1852 // T T::*
1853 // T (type::*)()
1854 // type (T::*)()
1855 // type (type::*)(T)
1856 // type (T::*)(T)
1857 // T (type::*)(T)
1858 // T (T::*)()
1859 // T (T::*)(T)
1860 case Type::MemberPointer: {
1861 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param);
1862 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg);
1863 if (!MemPtrArg)
1864 return Sema::TDK_NonDeducedMismatch;
1865
1866 QualType ParamPointeeType = MemPtrParam->getPointeeType();
1867 if (ParamPointeeType->isFunctionType())
1868 S.adjustMemberFunctionCC(ParamPointeeType, /*IsStatic=*/true,
1869 /*IsCtorOrDtor=*/false, Info.getLocation());
1870 QualType ArgPointeeType = MemPtrArg->getPointeeType();
1871 if (ArgPointeeType->isFunctionType())
1872 S.adjustMemberFunctionCC(ArgPointeeType, /*IsStatic=*/true,
1873 /*IsCtorOrDtor=*/false, Info.getLocation());
1874
1875 if (Sema::TemplateDeductionResult Result
1876 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1877 ParamPointeeType,
1878 ArgPointeeType,
1879 Info, Deduced,
1880 TDF & TDF_IgnoreQualifiers))
1881 return Result;
1882
1883 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1884 QualType(MemPtrParam->getClass(), 0),
1885 QualType(MemPtrArg->getClass(), 0),
1886 Info, Deduced,
1887 TDF & TDF_IgnoreQualifiers);
1888 }
1889
1890 // (clang extension)
1891 //
1892 // type(^)(T)
1893 // T(^)()
1894 // T(^)(T)
1895 case Type::BlockPointer: {
1896 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param);
1897 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg);
1898
1899 if (!BlockPtrArg)
1900 return Sema::TDK_NonDeducedMismatch;
1901
1902 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1903 BlockPtrParam->getPointeeType(),
1904 BlockPtrArg->getPointeeType(),
1905 Info, Deduced, 0);
1906 }
1907
1908 // (clang extension)
1909 //
1910 // T __attribute__(((ext_vector_type(<integral constant>))))
1911 case Type::ExtVector: {
1912 const ExtVectorType *VectorParam = cast<ExtVectorType>(Param);
1913 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
1914 // Make sure that the vectors have the same number of elements.
1915 if (VectorParam->getNumElements() != VectorArg->getNumElements())
1916 return Sema::TDK_NonDeducedMismatch;
1917
1918 // Perform deduction on the element types.
1919 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1920 VectorParam->getElementType(),
1921 VectorArg->getElementType(),
1922 Info, Deduced, TDF);
1923 }
1924
1925 if (const DependentSizedExtVectorType *VectorArg
1926 = dyn_cast<DependentSizedExtVectorType>(Arg)) {
1927 // We can't check the number of elements, since the argument has a
1928 // dependent number of elements. This can only occur during partial
1929 // ordering.
1930
1931 // Perform deduction on the element types.
1932 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1933 VectorParam->getElementType(),
1934 VectorArg->getElementType(),
1935 Info, Deduced, TDF);
1936 }
1937
1938 return Sema::TDK_NonDeducedMismatch;
1939 }
1940
1941 case Type::DependentVector: {
1942 const auto *VectorParam = cast<DependentVectorType>(Param);
1943
1944 if (const auto *VectorArg = dyn_cast<VectorType>(Arg)) {
1945 // Perform deduction on the element types.
1946 if (Sema::TemplateDeductionResult Result =
1947 DeduceTemplateArgumentsByTypeMatch(
1948 S, TemplateParams, VectorParam->getElementType(),
1949 VectorArg->getElementType(), Info, Deduced, TDF))
1950 return Result;
1951
1952 // Perform deduction on the vector size, if we can.
1953 NonTypeTemplateParmDecl *NTTP =
1954 getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
1955 if (!NTTP)
1956 return Sema::TDK_Success;
1957
1958 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
1959 ArgSize = VectorArg->getNumElements();
1960 // Note that we use the "array bound" rules here; just like in that
1961 // case, we don't have any particular type for the vector size, but
1962 // we can provide one if necessary.
1963 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
1964 S.Context.UnsignedIntTy, true,
1965 Info, Deduced);
1966 }
1967
1968 if (const auto *VectorArg = dyn_cast<DependentVectorType>(Arg)) {
1969 // Perform deduction on the element types.
1970 if (Sema::TemplateDeductionResult Result =
1971 DeduceTemplateArgumentsByTypeMatch(
1972 S, TemplateParams, VectorParam->getElementType(),
1973 VectorArg->getElementType(), Info, Deduced, TDF))
1974 return Result;
1975
1976 // Perform deduction on the vector size, if we can.
1977 NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
1978 Info, VectorParam->getSizeExpr());
1979 if (!NTTP)
1980 return Sema::TDK_Success;
1981
1982 return DeduceNonTypeTemplateArgument(
1983 S, TemplateParams, NTTP, VectorArg->getSizeExpr(), Info, Deduced);
1984 }
1985
1986 return Sema::TDK_NonDeducedMismatch;
1987 }
1988
1989 // (clang extension)
1990 //
1991 // T __attribute__(((ext_vector_type(N))))
1992 case Type::DependentSizedExtVector: {
1993 const DependentSizedExtVectorType *VectorParam
1994 = cast<DependentSizedExtVectorType>(Param);
1995
1996 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
1997 // Perform deduction on the element types.
1998 if (Sema::TemplateDeductionResult Result
1999 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2000 VectorParam->getElementType(),
2001 VectorArg->getElementType(),
2002 Info, Deduced, TDF))
2003 return Result;
2004
2005 // Perform deduction on the vector size, if we can.
2006 NonTypeTemplateParmDecl *NTTP
2007 = getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
2008 if (!NTTP)
2009 return Sema::TDK_Success;
2010
2011 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
2012 ArgSize = VectorArg->getNumElements();
2013 // Note that we use the "array bound" rules here; just like in that
2014 // case, we don't have any particular type for the vector size, but
2015 // we can provide one if necessary.
2016 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP, ArgSize,
2017 S.Context.IntTy, true, Info,
2018 Deduced);
2019 }
2020
2021 if (const DependentSizedExtVectorType *VectorArg
2022 = dyn_cast<DependentSizedExtVectorType>(Arg)) {
2023 // Perform deduction on the element types.
2024 if (Sema::TemplateDeductionResult Result
2025 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2026 VectorParam->getElementType(),
2027 VectorArg->getElementType(),
2028 Info, Deduced, TDF))
2029 return Result;
2030
2031 // Perform deduction on the vector size, if we can.
2032 NonTypeTemplateParmDecl *NTTP
2033 = getDeducedParameterFromExpr(Info, VectorParam->getSizeExpr());
2034 if (!NTTP)
2035 return Sema::TDK_Success;
2036
2037 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2038 VectorArg->getSizeExpr(),
2039 Info, Deduced);
2040 }
2041
2042 return Sema::TDK_NonDeducedMismatch;
2043 }
2044
2045 // (clang extension)
2046 //
2047 // T __attribute__(((address_space(N))))
2048 case Type::DependentAddressSpace: {
2049 const DependentAddressSpaceType *AddressSpaceParam =
2050 cast<DependentAddressSpaceType>(Param);
2051
2052 if (const DependentAddressSpaceType *AddressSpaceArg =
2053 dyn_cast<DependentAddressSpaceType>(Arg)) {
2054 // Perform deduction on the pointer type.
2055 if (Sema::TemplateDeductionResult Result =
2056 DeduceTemplateArgumentsByTypeMatch(
2057 S, TemplateParams, AddressSpaceParam->getPointeeType(),
2058 AddressSpaceArg->getPointeeType(), Info, Deduced, TDF))
2059 return Result;
2060
2061 // Perform deduction on the address space, if we can.
2062 NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
2063 Info, AddressSpaceParam->getAddrSpaceExpr());
2064 if (!NTTP)
2065 return Sema::TDK_Success;
2066
2067 return DeduceNonTypeTemplateArgument(
2068 S, TemplateParams, NTTP, AddressSpaceArg->getAddrSpaceExpr(), Info,
2069 Deduced);
2070 }
2071
2072 if (isTargetAddressSpace(Arg.getAddressSpace())) {
2073 llvm::APSInt ArgAddressSpace(S.Context.getTypeSize(S.Context.IntTy),
2074 false);
2075 ArgAddressSpace = toTargetAddressSpace(Arg.getAddressSpace());
2076
2077 // Perform deduction on the pointer types.
2078 if (Sema::TemplateDeductionResult Result =
2079 DeduceTemplateArgumentsByTypeMatch(
2080 S, TemplateParams, AddressSpaceParam->getPointeeType(),
2081 S.Context.removeAddrSpaceQualType(Arg), Info, Deduced, TDF))
2082 return Result;
2083
2084 // Perform deduction on the address space, if we can.
2085 NonTypeTemplateParmDecl *NTTP = getDeducedParameterFromExpr(
2086 Info, AddressSpaceParam->getAddrSpaceExpr());
2087 if (!NTTP)
2088 return Sema::TDK_Success;
2089
2090 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2091 ArgAddressSpace, S.Context.IntTy,
2092 true, Info, Deduced);
2093 }
2094
2095 return Sema::TDK_NonDeducedMismatch;
2096 }
2097
2098 case Type::TypeOfExpr:
2099 case Type::TypeOf:
2100 case Type::DependentName:
2101 case Type::UnresolvedUsing:
2102 case Type::Decltype:
2103 case Type::UnaryTransform:
2104 case Type::Auto:
2105 case Type::DeducedTemplateSpecialization:
2106 case Type::DependentTemplateSpecialization:
2107 case Type::PackExpansion:
2108 case Type::Pipe:
2109 // No template argument deduction for these types
2110 return Sema::TDK_Success;
2111 }
2112
2113 llvm_unreachable("Invalid Type Class!")::llvm::llvm_unreachable_internal("Invalid Type Class!", "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2113)
;
2114}
2115
2116static Sema::TemplateDeductionResult
2117DeduceTemplateArguments(Sema &S,
2118 TemplateParameterList *TemplateParams,
2119 const TemplateArgument &Param,
2120 TemplateArgument Arg,
2121 TemplateDeductionInfo &Info,
2122 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
2123 // If the template argument is a pack expansion, perform template argument
2124 // deduction against the pattern of that expansion. This only occurs during
2125 // partial ordering.
2126 if (Arg.isPackExpansion())
2127 Arg = Arg.getPackExpansionPattern();
2128
2129 switch (Param.getKind()) {
2130 case TemplateArgument::Null:
2131 llvm_unreachable("Null template argument in parameter list")::llvm::llvm_unreachable_internal("Null template argument in parameter list"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2131)
;
2132
2133 case TemplateArgument::Type:
2134 if (Arg.getKind() == TemplateArgument::Type)
2135 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
2136 Param.getAsType(),
2137 Arg.getAsType(),
2138 Info, Deduced, 0);
2139 Info.FirstArg = Param;
2140 Info.SecondArg = Arg;
2141 return Sema::TDK_NonDeducedMismatch;
2142
2143 case TemplateArgument::Template:
2144 if (Arg.getKind() == TemplateArgument::Template)
2145 return DeduceTemplateArguments(S, TemplateParams,
2146 Param.getAsTemplate(),
2147 Arg.getAsTemplate(), Info, Deduced);
2148 Info.FirstArg = Param;
2149 Info.SecondArg = Arg;
2150 return Sema::TDK_NonDeducedMismatch;
2151
2152 case TemplateArgument::TemplateExpansion:
2153 llvm_unreachable("caller should handle pack expansions")::llvm::llvm_unreachable_internal("caller should handle pack expansions"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2153)
;
2154
2155 case TemplateArgument::Declaration:
2156 if (Arg.getKind() == TemplateArgument::Declaration &&
2157 isSameDeclaration(Param.getAsDecl(), Arg.getAsDecl()))
2158 return Sema::TDK_Success;
2159
2160 Info.FirstArg = Param;
2161 Info.SecondArg = Arg;
2162 return Sema::TDK_NonDeducedMismatch;
2163
2164 case TemplateArgument::NullPtr:
2165 if (Arg.getKind() == TemplateArgument::NullPtr &&
2166 S.Context.hasSameType(Param.getNullPtrType(), Arg.getNullPtrType()))
2167 return Sema::TDK_Success;
2168
2169 Info.FirstArg = Param;
2170 Info.SecondArg = Arg;
2171 return Sema::TDK_NonDeducedMismatch;
2172
2173 case TemplateArgument::Integral:
2174 if (Arg.getKind() == TemplateArgument::Integral) {
2175 if (hasSameExtendedValue(Param.getAsIntegral(), Arg.getAsIntegral()))
2176 return Sema::TDK_Success;
2177
2178 Info.FirstArg = Param;
2179 Info.SecondArg = Arg;
2180 return Sema::TDK_NonDeducedMismatch;
2181 }
2182
2183 if (Arg.getKind() == TemplateArgument::Expression) {
2184 Info.FirstArg = Param;
2185 Info.SecondArg = Arg;
2186 return Sema::TDK_NonDeducedMismatch;
2187 }
2188
2189 Info.FirstArg = Param;
2190 Info.SecondArg = Arg;
2191 return Sema::TDK_NonDeducedMismatch;
2192
2193 case TemplateArgument::Expression:
2194 if (NonTypeTemplateParmDecl *NTTP
2195 = getDeducedParameterFromExpr(Info, Param.getAsExpr())) {
2196 if (Arg.getKind() == TemplateArgument::Integral)
2197 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2198 Arg.getAsIntegral(),
2199 Arg.getIntegralType(),
2200 /*ArrayBound=*/false,
2201 Info, Deduced);
2202 if (Arg.getKind() == TemplateArgument::NullPtr)
2203 return DeduceNullPtrTemplateArgument(S, TemplateParams, NTTP,
2204 Arg.getNullPtrType(),
2205 Info, Deduced);
2206 if (Arg.getKind() == TemplateArgument::Expression)
2207 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2208 Arg.getAsExpr(), Info, Deduced);
2209 if (Arg.getKind() == TemplateArgument::Declaration)
2210 return DeduceNonTypeTemplateArgument(S, TemplateParams, NTTP,
2211 Arg.getAsDecl(),
2212 Arg.getParamTypeForDecl(),
2213 Info, Deduced);
2214
2215 Info.FirstArg = Param;
2216 Info.SecondArg = Arg;
2217 return Sema::TDK_NonDeducedMismatch;
2218 }
2219
2220 // Can't deduce anything, but that's okay.
2221 return Sema::TDK_Success;
2222
2223 case TemplateArgument::Pack:
2224 llvm_unreachable("Argument packs should be expanded by the caller!")::llvm::llvm_unreachable_internal("Argument packs should be expanded by the caller!"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2224)
;
2225 }
2226
2227 llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2227)
;
2228}
2229
2230/// Determine whether there is a template argument to be used for
2231/// deduction.
2232///
2233/// This routine "expands" argument packs in-place, overriding its input
2234/// parameters so that \c Args[ArgIdx] will be the available template argument.
2235///
2236/// \returns true if there is another template argument (which will be at
2237/// \c Args[ArgIdx]), false otherwise.
2238static bool hasTemplateArgumentForDeduction(ArrayRef<TemplateArgument> &Args,
2239 unsigned &ArgIdx) {
2240 if (ArgIdx == Args.size())
2241 return false;
2242
2243 const TemplateArgument &Arg = Args[ArgIdx];
2244 if (Arg.getKind() != TemplateArgument::Pack)
2245 return true;
2246
2247 assert(ArgIdx == Args.size() - 1 && "Pack not at the end of argument list?")((ArgIdx == Args.size() - 1 && "Pack not at the end of argument list?"
) ? static_cast<void> (0) : __assert_fail ("ArgIdx == Args.size() - 1 && \"Pack not at the end of argument list?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2247, __PRETTY_FUNCTION__))
;
2248 Args = Arg.pack_elements();
2249 ArgIdx = 0;
2250 return ArgIdx < Args.size();
2251}
2252
2253/// Determine whether the given set of template arguments has a pack
2254/// expansion that is not the last template argument.
2255static bool hasPackExpansionBeforeEnd(ArrayRef<TemplateArgument> Args) {
2256 bool FoundPackExpansion = false;
2257 for (const auto &A : Args) {
2258 if (FoundPackExpansion)
2259 return true;
2260
2261 if (A.getKind() == TemplateArgument::Pack)
2262 return hasPackExpansionBeforeEnd(A.pack_elements());
2263
2264 // FIXME: If this is a fixed-arity pack expansion from an outer level of
2265 // templates, it should not be treated as a pack expansion.
2266 if (A.isPackExpansion())
2267 FoundPackExpansion = true;
2268 }
2269
2270 return false;
2271}
2272
2273static Sema::TemplateDeductionResult
2274DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
2275 ArrayRef<TemplateArgument> Params,
2276 ArrayRef<TemplateArgument> Args,
2277 TemplateDeductionInfo &Info,
2278 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2279 bool NumberOfArgumentsMustMatch) {
2280 // C++0x [temp.deduct.type]p9:
2281 // If the template argument list of P contains a pack expansion that is not
2282 // the last template argument, the entire template argument list is a
2283 // non-deduced context.
2284 if (hasPackExpansionBeforeEnd(Params))
2285 return Sema::TDK_Success;
2286
2287 // C++0x [temp.deduct.type]p9:
2288 // If P has a form that contains <T> or <i>, then each argument Pi of the
2289 // respective template argument list P is compared with the corresponding
2290 // argument Ai of the corresponding template argument list of A.
2291 unsigned ArgIdx = 0, ParamIdx = 0;
2292 for (; hasTemplateArgumentForDeduction(Params, ParamIdx); ++ParamIdx) {
2293 if (!Params[ParamIdx].isPackExpansion()) {
2294 // The simple case: deduce template arguments by matching Pi and Ai.
2295
2296 // Check whether we have enough arguments.
2297 if (!hasTemplateArgumentForDeduction(Args, ArgIdx))
2298 return NumberOfArgumentsMustMatch
2299 ? Sema::TDK_MiscellaneousDeductionFailure
2300 : Sema::TDK_Success;
2301
2302 // C++1z [temp.deduct.type]p9:
2303 // During partial ordering, if Ai was originally a pack expansion [and]
2304 // Pi is not a pack expansion, template argument deduction fails.
2305 if (Args[ArgIdx].isPackExpansion())
2306 return Sema::TDK_MiscellaneousDeductionFailure;
2307
2308 // Perform deduction for this Pi/Ai pair.
2309 if (Sema::TemplateDeductionResult Result
2310 = DeduceTemplateArguments(S, TemplateParams,
2311 Params[ParamIdx], Args[ArgIdx],
2312 Info, Deduced))
2313 return Result;
2314
2315 // Move to the next argument.
2316 ++ArgIdx;
2317 continue;
2318 }
2319
2320 // The parameter is a pack expansion.
2321
2322 // C++0x [temp.deduct.type]p9:
2323 // If Pi is a pack expansion, then the pattern of Pi is compared with
2324 // each remaining argument in the template argument list of A. Each
2325 // comparison deduces template arguments for subsequent positions in the
2326 // template parameter packs expanded by Pi.
2327 TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern();
2328
2329 // Prepare to deduce the packs within the pattern.
2330 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
2331
2332 // Keep track of the deduced template arguments for each parameter pack
2333 // expanded by this pack expansion (the outer index) and for each
2334 // template argument (the inner SmallVectors).
2335 for (; hasTemplateArgumentForDeduction(Args, ArgIdx) &&
2336 PackScope.hasNextElement();
2337 ++ArgIdx) {
2338 // Deduce template arguments from the pattern.
2339 if (Sema::TemplateDeductionResult Result
2340 = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx],
2341 Info, Deduced))
2342 return Result;
2343
2344 PackScope.nextPackElement();
2345 }
2346
2347 // Build argument packs for each of the parameter packs expanded by this
2348 // pack expansion.
2349 if (auto Result = PackScope.finish())
2350 return Result;
2351 }
2352
2353 return Sema::TDK_Success;
2354}
2355
2356static Sema::TemplateDeductionResult
2357DeduceTemplateArguments(Sema &S,
2358 TemplateParameterList *TemplateParams,
2359 const TemplateArgumentList &ParamList,
2360 const TemplateArgumentList &ArgList,
2361 TemplateDeductionInfo &Info,
2362 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
2363 return DeduceTemplateArguments(S, TemplateParams, ParamList.asArray(),
2364 ArgList.asArray(), Info, Deduced,
2365 /*NumberOfArgumentsMustMatch*/false);
2366}
2367
2368/// Determine whether two template arguments are the same.
2369static bool isSameTemplateArg(ASTContext &Context,
2370 TemplateArgument X,
2371 const TemplateArgument &Y,
2372 bool PackExpansionMatchesPack = false) {
2373 // If we're checking deduced arguments (X) against original arguments (Y),
2374 // we will have flattened packs to non-expansions in X.
2375 if (PackExpansionMatchesPack && X.isPackExpansion() && !Y.isPackExpansion())
2376 X = X.getPackExpansionPattern();
2377
2378 if (X.getKind() != Y.getKind())
2379 return false;
2380
2381 switch (X.getKind()) {
2382 case TemplateArgument::Null:
2383 llvm_unreachable("Comparing NULL template argument")::llvm::llvm_unreachable_internal("Comparing NULL template argument"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2383)
;
2384
2385 case TemplateArgument::Type:
2386 return Context.getCanonicalType(X.getAsType()) ==
2387 Context.getCanonicalType(Y.getAsType());
2388
2389 case TemplateArgument::Declaration:
2390 return isSameDeclaration(X.getAsDecl(), Y.getAsDecl());
2391
2392 case TemplateArgument::NullPtr:
2393 return Context.hasSameType(X.getNullPtrType(), Y.getNullPtrType());
2394
2395 case TemplateArgument::Template:
2396 case TemplateArgument::TemplateExpansion:
2397 return Context.getCanonicalTemplateName(
2398 X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() ==
2399 Context.getCanonicalTemplateName(
2400 Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer();
2401
2402 case TemplateArgument::Integral:
2403 return hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral());
2404
2405 case TemplateArgument::Expression: {
2406 llvm::FoldingSetNodeID XID, YID;
2407 X.getAsExpr()->Profile(XID, Context, true);
2408 Y.getAsExpr()->Profile(YID, Context, true);
2409 return XID == YID;
2410 }
2411
2412 case TemplateArgument::Pack:
2413 if (X.pack_size() != Y.pack_size())
2414 return false;
2415
2416 for (TemplateArgument::pack_iterator XP = X.pack_begin(),
2417 XPEnd = X.pack_end(),
2418 YP = Y.pack_begin();
2419 XP != XPEnd; ++XP, ++YP)
2420 if (!isSameTemplateArg(Context, *XP, *YP, PackExpansionMatchesPack))
2421 return false;
2422
2423 return true;
2424 }
2425
2426 llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2426)
;
2427}
2428
2429/// Allocate a TemplateArgumentLoc where all locations have
2430/// been initialized to the given location.
2431///
2432/// \param Arg The template argument we are producing template argument
2433/// location information for.
2434///
2435/// \param NTTPType For a declaration template argument, the type of
2436/// the non-type template parameter that corresponds to this template
2437/// argument. Can be null if no type sugar is available to add to the
2438/// type from the template argument.
2439///
2440/// \param Loc The source location to use for the resulting template
2441/// argument.
2442TemplateArgumentLoc
2443Sema::getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
2444 QualType NTTPType, SourceLocation Loc) {
2445 switch (Arg.getKind()) {
2446 case TemplateArgument::Null:
2447 llvm_unreachable("Can't get a NULL template argument here")::llvm::llvm_unreachable_internal("Can't get a NULL template argument here"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2447)
;
2448
2449 case TemplateArgument::Type:
2450 return TemplateArgumentLoc(
2451 Arg, Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc));
2452
2453 case TemplateArgument::Declaration: {
2454 if (NTTPType.isNull())
2455 NTTPType = Arg.getParamTypeForDecl();
2456 Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
2457 .getAs<Expr>();
2458 return TemplateArgumentLoc(TemplateArgument(E), E);
2459 }
2460
2461 case TemplateArgument::NullPtr: {
2462 if (NTTPType.isNull())
2463 NTTPType = Arg.getNullPtrType();
2464 Expr *E = BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
2465 .getAs<Expr>();
2466 return TemplateArgumentLoc(TemplateArgument(NTTPType, /*isNullPtr*/true),
2467 E);
2468 }
2469
2470 case TemplateArgument::Integral: {
2471 Expr *E =
2472 BuildExpressionFromIntegralTemplateArgument(Arg, Loc).getAs<Expr>();
2473 return TemplateArgumentLoc(TemplateArgument(E), E);
2474 }
2475
2476 case TemplateArgument::Template:
2477 case TemplateArgument::TemplateExpansion: {
2478 NestedNameSpecifierLocBuilder Builder;
2479 TemplateName Template = Arg.getAsTemplate();
2480 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
2481 Builder.MakeTrivial(Context, DTN->getQualifier(), Loc);
2482 else if (QualifiedTemplateName *QTN =
2483 Template.getAsQualifiedTemplateName())
2484 Builder.MakeTrivial(Context, QTN->getQualifier(), Loc);
2485
2486 if (Arg.getKind() == TemplateArgument::Template)
2487 return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(Context),
2488 Loc);
2489
2490 return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(Context),
2491 Loc, Loc);
2492 }
2493
2494 case TemplateArgument::Expression:
2495 return TemplateArgumentLoc(Arg, Arg.getAsExpr());
2496
2497 case TemplateArgument::Pack:
2498 return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
2499 }
2500
2501 llvm_unreachable("Invalid TemplateArgument Kind!")::llvm::llvm_unreachable_internal("Invalid TemplateArgument Kind!"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2501)
;
2502}
2503
2504/// Convert the given deduced template argument and add it to the set of
2505/// fully-converted template arguments.
2506static bool
2507ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param,
2508 DeducedTemplateArgument Arg,
2509 NamedDecl *Template,
2510 TemplateDeductionInfo &Info,
2511 bool IsDeduced,
2512 SmallVectorImpl<TemplateArgument> &Output) {
2513 auto ConvertArg = [&](DeducedTemplateArgument Arg,
2514 unsigned ArgumentPackIndex) {
2515 // Convert the deduced template argument into a template
2516 // argument that we can check, almost as if the user had written
2517 // the template argument explicitly.
2518 TemplateArgumentLoc ArgLoc =
2519 S.getTrivialTemplateArgumentLoc(Arg, QualType(), Info.getLocation());
2520
2521 // Check the template argument, converting it as necessary.
2522 return S.CheckTemplateArgument(
2523 Param, ArgLoc, Template, Template->getLocation(),
2524 Template->getSourceRange().getEnd(), ArgumentPackIndex, Output,
2525 IsDeduced
2526 ? (Arg.wasDeducedFromArrayBound() ? Sema::CTAK_DeducedFromArrayBound
2527 : Sema::CTAK_Deduced)
2528 : Sema::CTAK_Specified);
2529 };
2530
2531 if (Arg.getKind() == TemplateArgument::Pack) {
2532 // This is a template argument pack, so check each of its arguments against
2533 // the template parameter.
2534 SmallVector<TemplateArgument, 2> PackedArgsBuilder;
2535 for (const auto &P : Arg.pack_elements()) {
2536 // When converting the deduced template argument, append it to the
2537 // general output list. We need to do this so that the template argument
2538 // checking logic has all of the prior template arguments available.
2539 DeducedTemplateArgument InnerArg(P);
2540 InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound());
2541 assert(InnerArg.getKind() != TemplateArgument::Pack &&((InnerArg.getKind() != TemplateArgument::Pack && "deduced nested pack"
) ? static_cast<void> (0) : __assert_fail ("InnerArg.getKind() != TemplateArgument::Pack && \"deduced nested pack\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2542, __PRETTY_FUNCTION__))
2542 "deduced nested pack")((InnerArg.getKind() != TemplateArgument::Pack && "deduced nested pack"
) ? static_cast<void> (0) : __assert_fail ("InnerArg.getKind() != TemplateArgument::Pack && \"deduced nested pack\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2542, __PRETTY_FUNCTION__))
;
2543 if (P.isNull()) {
2544 // We deduced arguments for some elements of this pack, but not for
2545 // all of them. This happens if we get a conditionally-non-deduced
2546 // context in a pack expansion (such as an overload set in one of the
2547 // arguments).
2548 S.Diag(Param->getLocation(),
2549 diag::err_template_arg_deduced_incomplete_pack)
2550 << Arg << Param;
2551 return true;
2552 }
2553 if (ConvertArg(InnerArg, PackedArgsBuilder.size()))
2554 return true;
2555
2556 // Move the converted template argument into our argument pack.
2557 PackedArgsBuilder.push_back(Output.pop_back_val());
2558 }
2559
2560 // If the pack is empty, we still need to substitute into the parameter
2561 // itself, in case that substitution fails.
2562 if (PackedArgsBuilder.empty()) {
2563 LocalInstantiationScope Scope(S);
2564 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Output);
2565 MultiLevelTemplateArgumentList Args(TemplateArgs);
2566
2567 if (auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
2568 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
2569 NTTP, Output,
2570 Template->getSourceRange());
2571 if (Inst.isInvalid() ||
2572 S.SubstType(NTTP->getType(), Args, NTTP->getLocation(),
2573 NTTP->getDeclName()).isNull())
2574 return true;
2575 } else if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param)) {
2576 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
2577 TTP, Output,
2578 Template->getSourceRange());
2579 if (Inst.isInvalid() || !S.SubstDecl(TTP, S.CurContext, Args))
2580 return true;
2581 }
2582 // For type parameters, no substitution is ever required.
2583 }
2584
2585 // Create the resulting argument pack.
2586 Output.push_back(
2587 TemplateArgument::CreatePackCopy(S.Context, PackedArgsBuilder));
2588 return false;
2589 }
2590
2591 return ConvertArg(Arg, 0);
2592}
2593
2594// FIXME: This should not be a template, but
2595// ClassTemplatePartialSpecializationDecl sadly does not derive from
2596// TemplateDecl.
2597template<typename TemplateDeclT>
2598static Sema::TemplateDeductionResult ConvertDeducedTemplateArguments(
2599 Sema &S, TemplateDeclT *Template, bool IsDeduced,
2600 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2601 TemplateDeductionInfo &Info, SmallVectorImpl<TemplateArgument> &Builder,
2602 LocalInstantiationScope *CurrentInstantiationScope = nullptr,
2603 unsigned NumAlreadyConverted = 0, bool PartialOverloading = false) {
2604 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
2605
2606 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
2607 NamedDecl *Param = TemplateParams->getParam(I);
2608
2609 // C++0x [temp.arg.explicit]p3:
2610 // A trailing template parameter pack (14.5.3) not otherwise deduced will
2611 // be deduced to an empty sequence of template arguments.
2612 // FIXME: Where did the word "trailing" come from?
2613 if (Deduced[I].isNull() && Param->isTemplateParameterPack()) {
2614 if (auto Result = PackDeductionScope(S, TemplateParams, Deduced, Info, I)
2615 .finish(/*TreatNoDeductionsAsNonDeduced*/false))
2616 return Result;
2617 }
2618
2619 if (!Deduced[I].isNull()) {
2620 if (I < NumAlreadyConverted) {
2621 // We may have had explicitly-specified template arguments for a
2622 // template parameter pack (that may or may not have been extended
2623 // via additional deduced arguments).
2624 if (Param->isParameterPack() && CurrentInstantiationScope &&
2625 CurrentInstantiationScope->getPartiallySubstitutedPack() == Param) {
2626 // Forget the partially-substituted pack; its substitution is now
2627 // complete.
2628 CurrentInstantiationScope->ResetPartiallySubstitutedPack();
2629 // We still need to check the argument in case it was extended by
2630 // deduction.
2631 } else {
2632 // We have already fully type-checked and converted this
2633 // argument, because it was explicitly-specified. Just record the
2634 // presence of this argument.
2635 Builder.push_back(Deduced[I]);
2636 continue;
2637 }
2638 }
2639
2640 // We may have deduced this argument, so it still needs to be
2641 // checked and converted.
2642 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], Template, Info,
2643 IsDeduced, Builder)) {
2644 Info.Param = makeTemplateParameter(Param);
2645 // FIXME: These template arguments are temporary. Free them!
2646 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2647 return Sema::TDK_SubstitutionFailure;
2648 }
2649
2650 continue;
2651 }
2652
2653 // Substitute into the default template argument, if available.
2654 bool HasDefaultArg = false;
2655 TemplateDecl *TD = dyn_cast<TemplateDecl>(Template);
2656 if (!TD) {
2657 assert(isa<ClassTemplatePartialSpecializationDecl>(Template) ||((isa<ClassTemplatePartialSpecializationDecl>(Template)
|| isa<VarTemplatePartialSpecializationDecl>(Template)
) ? static_cast<void> (0) : __assert_fail ("isa<ClassTemplatePartialSpecializationDecl>(Template) || isa<VarTemplatePartialSpecializationDecl>(Template)"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2658, __PRETTY_FUNCTION__))
2658 isa<VarTemplatePartialSpecializationDecl>(Template))((isa<ClassTemplatePartialSpecializationDecl>(Template)
|| isa<VarTemplatePartialSpecializationDecl>(Template)
) ? static_cast<void> (0) : __assert_fail ("isa<ClassTemplatePartialSpecializationDecl>(Template) || isa<VarTemplatePartialSpecializationDecl>(Template)"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 2658, __PRETTY_FUNCTION__))
;
2659 return Sema::TDK_Incomplete;
2660 }
2661
2662 TemplateArgumentLoc DefArg = S.SubstDefaultTemplateArgumentIfAvailable(
2663 TD, TD->getLocation(), TD->getSourceRange().getEnd(), Param, Builder,
2664 HasDefaultArg);
2665
2666 // If there was no default argument, deduction is incomplete.
2667 if (DefArg.getArgument().isNull()) {
2668 Info.Param = makeTemplateParameter(
2669 const_cast<NamedDecl *>(TemplateParams->getParam(I)));
2670 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2671 if (PartialOverloading) break;
2672
2673 return HasDefaultArg ? Sema::TDK_SubstitutionFailure
2674 : Sema::TDK_Incomplete;
2675 }
2676
2677 // Check whether we can actually use the default argument.
2678 if (S.CheckTemplateArgument(Param, DefArg, TD, TD->getLocation(),
2679 TD->getSourceRange().getEnd(), 0, Builder,
2680 Sema::CTAK_Specified)) {
2681 Info.Param = makeTemplateParameter(
2682 const_cast<NamedDecl *>(TemplateParams->getParam(I)));
2683 // FIXME: These template arguments are temporary. Free them!
2684 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2685 return Sema::TDK_SubstitutionFailure;
2686 }
2687
2688 // If we get here, we successfully used the default template argument.
2689 }
2690
2691 return Sema::TDK_Success;
2692}
2693
2694static DeclContext *getAsDeclContextOrEnclosing(Decl *D) {
2695 if (auto *DC = dyn_cast<DeclContext>(D))
2696 return DC;
2697 return D->getDeclContext();
2698}
2699
2700template<typename T> struct IsPartialSpecialization {
2701 static constexpr bool value = false;
2702};
2703template<>
2704struct IsPartialSpecialization<ClassTemplatePartialSpecializationDecl> {
2705 static constexpr bool value = true;
2706};
2707template<>
2708struct IsPartialSpecialization<VarTemplatePartialSpecializationDecl> {
2709 static constexpr bool value = true;
2710};
2711
2712/// Complete template argument deduction for a partial specialization.
2713template <typename T>
2714static typename std::enable_if<IsPartialSpecialization<T>::value,
2715 Sema::TemplateDeductionResult>::type
2716FinishTemplateArgumentDeduction(
2717 Sema &S, T *Partial, bool IsPartialOrdering,
2718 const TemplateArgumentList &TemplateArgs,
2719 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2720 TemplateDeductionInfo &Info) {
2721 // Unevaluated SFINAE context.
2722 EnterExpressionEvaluationContext Unevaluated(
2723 S, Sema::ExpressionEvaluationContext::Unevaluated);
2724 Sema::SFINAETrap Trap(S);
2725
2726 Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Partial));
2727
2728 // C++ [temp.deduct.type]p2:
2729 // [...] or if any template argument remains neither deduced nor
2730 // explicitly specified, template argument deduction fails.
2731 SmallVector<TemplateArgument, 4> Builder;
2732 if (auto Result = ConvertDeducedTemplateArguments(
2733 S, Partial, IsPartialOrdering, Deduced, Info, Builder))
2734 return Result;
2735
2736 // Form the template argument list from the deduced template arguments.
2737 TemplateArgumentList *DeducedArgumentList
2738 = TemplateArgumentList::CreateCopy(S.Context, Builder);
2739
2740 Info.reset(DeducedArgumentList);
2741
2742 // Substitute the deduced template arguments into the template
2743 // arguments of the class template partial specialization, and
2744 // verify that the instantiated template arguments are both valid
2745 // and are equivalent to the template arguments originally provided
2746 // to the class template.
2747 LocalInstantiationScope InstScope(S);
2748 auto *Template = Partial->getSpecializedTemplate();
2749 const ASTTemplateArgumentListInfo *PartialTemplArgInfo =
2750 Partial->getTemplateArgsAsWritten();
2751 const TemplateArgumentLoc *PartialTemplateArgs =
2752 PartialTemplArgInfo->getTemplateArgs();
2753
2754 TemplateArgumentListInfo InstArgs(PartialTemplArgInfo->LAngleLoc,
2755 PartialTemplArgInfo->RAngleLoc);
2756
2757 if (S.Subst(PartialTemplateArgs, PartialTemplArgInfo->NumTemplateArgs,
2758 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) {
2759 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx;
2760 if (ParamIdx >= Partial->getTemplateParameters()->size())
2761 ParamIdx = Partial->getTemplateParameters()->size() - 1;
2762
2763 Decl *Param = const_cast<NamedDecl *>(
2764 Partial->getTemplateParameters()->getParam(ParamIdx));
2765 Info.Param = makeTemplateParameter(Param);
2766 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument();
2767 return Sema::TDK_SubstitutionFailure;
2768 }
2769
2770 SmallVector<TemplateArgument, 4> ConvertedInstArgs;
2771 if (S.CheckTemplateArgumentList(Template, Partial->getLocation(), InstArgs,
2772 false, ConvertedInstArgs))
2773 return Sema::TDK_SubstitutionFailure;
2774
2775 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
2776 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
2777 TemplateArgument InstArg = ConvertedInstArgs.data()[I];
2778 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) {
2779 Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
2780 Info.FirstArg = TemplateArgs[I];
2781 Info.SecondArg = InstArg;
2782 return Sema::TDK_NonDeducedMismatch;
2783 }
2784 }
2785
2786 if (Trap.hasErrorOccurred())
2787 return Sema::TDK_SubstitutionFailure;
2788
2789 return Sema::TDK_Success;
2790}
2791
2792/// Complete template argument deduction for a class or variable template,
2793/// when partial ordering against a partial specialization.
2794// FIXME: Factor out duplication with partial specialization version above.
2795static Sema::TemplateDeductionResult FinishTemplateArgumentDeduction(
2796 Sema &S, TemplateDecl *Template, bool PartialOrdering,
2797 const TemplateArgumentList &TemplateArgs,
2798 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2799 TemplateDeductionInfo &Info) {
2800 // Unevaluated SFINAE context.
2801 EnterExpressionEvaluationContext Unevaluated(
2802 S, Sema::ExpressionEvaluationContext::Unevaluated);
2803 Sema::SFINAETrap Trap(S);
2804
2805 Sema::ContextRAII SavedContext(S, getAsDeclContextOrEnclosing(Template));
2806
2807 // C++ [temp.deduct.type]p2:
2808 // [...] or if any template argument remains neither deduced nor
2809 // explicitly specified, template argument deduction fails.
2810 SmallVector<TemplateArgument, 4> Builder;
2811 if (auto Result = ConvertDeducedTemplateArguments(
2812 S, Template, /*IsDeduced*/PartialOrdering, Deduced, Info, Builder))
2813 return Result;
2814
2815 // Check that we produced the correct argument list.
2816 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
2817 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
2818 TemplateArgument InstArg = Builder[I];
2819 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg,
2820 /*PackExpansionMatchesPack*/true)) {
2821 Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
2822 Info.FirstArg = TemplateArgs[I];
2823 Info.SecondArg = InstArg;
2824 return Sema::TDK_NonDeducedMismatch;
2825 }
2826 }
2827
2828 if (Trap.hasErrorOccurred())
2829 return Sema::TDK_SubstitutionFailure;
2830
2831 return Sema::TDK_Success;
2832}
2833
2834
2835/// Perform template argument deduction to determine whether
2836/// the given template arguments match the given class template
2837/// partial specialization per C++ [temp.class.spec.match].
2838Sema::TemplateDeductionResult
2839Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
2840 const TemplateArgumentList &TemplateArgs,
2841 TemplateDeductionInfo &Info) {
2842 if (Partial->isInvalidDecl())
2843 return TDK_Invalid;
2844
2845 // C++ [temp.class.spec.match]p2:
2846 // A partial specialization matches a given actual template
2847 // argument list if the template arguments of the partial
2848 // specialization can be deduced from the actual template argument
2849 // list (14.8.2).
2850
2851 // Unevaluated SFINAE context.
2852 EnterExpressionEvaluationContext Unevaluated(
2853 *this, Sema::ExpressionEvaluationContext::Unevaluated);
2854 SFINAETrap Trap(*this);
2855
2856 SmallVector<DeducedTemplateArgument, 4> Deduced;
2857 Deduced.resize(Partial->getTemplateParameters()->size());
2858 if (TemplateDeductionResult Result
2859 = ::DeduceTemplateArguments(*this,
2860 Partial->getTemplateParameters(),
2861 Partial->getTemplateArgs(),
2862 TemplateArgs, Info, Deduced))
2863 return Result;
2864
2865 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
2866 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
2867 Info);
2868 if (Inst.isInvalid())
2869 return TDK_InstantiationDepth;
2870
2871 if (Trap.hasErrorOccurred())
2872 return Sema::TDK_SubstitutionFailure;
2873
2874 return ::FinishTemplateArgumentDeduction(
2875 *this, Partial, /*IsPartialOrdering=*/false, TemplateArgs, Deduced, Info);
2876}
2877
2878/// Perform template argument deduction to determine whether
2879/// the given template arguments match the given variable template
2880/// partial specialization per C++ [temp.class.spec.match].
2881Sema::TemplateDeductionResult
2882Sema::DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
2883 const TemplateArgumentList &TemplateArgs,
2884 TemplateDeductionInfo &Info) {
2885 if (Partial->isInvalidDecl())
2886 return TDK_Invalid;
2887
2888 // C++ [temp.class.spec.match]p2:
2889 // A partial specialization matches a given actual template
2890 // argument list if the template arguments of the partial
2891 // specialization can be deduced from the actual template argument
2892 // list (14.8.2).
2893
2894 // Unevaluated SFINAE context.
2895 EnterExpressionEvaluationContext Unevaluated(
2896 *this, Sema::ExpressionEvaluationContext::Unevaluated);
2897 SFINAETrap Trap(*this);
2898
2899 SmallVector<DeducedTemplateArgument, 4> Deduced;
2900 Deduced.resize(Partial->getTemplateParameters()->size());
2901 if (TemplateDeductionResult Result = ::DeduceTemplateArguments(
2902 *this, Partial->getTemplateParameters(), Partial->getTemplateArgs(),
2903 TemplateArgs, Info, Deduced))
2904 return Result;
2905
2906 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
2907 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
2908 Info);
2909 if (Inst.isInvalid())
2910 return TDK_InstantiationDepth;
2911
2912 if (Trap.hasErrorOccurred())
2913 return Sema::TDK_SubstitutionFailure;
2914
2915 return ::FinishTemplateArgumentDeduction(
2916 *this, Partial, /*IsPartialOrdering=*/false, TemplateArgs, Deduced, Info);
2917}
2918
2919/// Determine whether the given type T is a simple-template-id type.
2920static bool isSimpleTemplateIdType(QualType T) {
2921 if (const TemplateSpecializationType *Spec
2922 = T->getAs<TemplateSpecializationType>())
2923 return Spec->getTemplateName().getAsTemplateDecl() != nullptr;
2924
2925 // C++17 [temp.local]p2:
2926 // the injected-class-name [...] is equivalent to the template-name followed
2927 // by the template-arguments of the class template specialization or partial
2928 // specialization enclosed in <>
2929 // ... which means it's equivalent to a simple-template-id.
2930 //
2931 // This only arises during class template argument deduction for a copy
2932 // deduction candidate, where it permits slicing.
2933 if (T->getAs<InjectedClassNameType>())
2934 return true;
2935
2936 return false;
2937}
2938
2939/// Substitute the explicitly-provided template arguments into the
2940/// given function template according to C++ [temp.arg.explicit].
2941///
2942/// \param FunctionTemplate the function template into which the explicit
2943/// template arguments will be substituted.
2944///
2945/// \param ExplicitTemplateArgs the explicitly-specified template
2946/// arguments.
2947///
2948/// \param Deduced the deduced template arguments, which will be populated
2949/// with the converted and checked explicit template arguments.
2950///
2951/// \param ParamTypes will be populated with the instantiated function
2952/// parameters.
2953///
2954/// \param FunctionType if non-NULL, the result type of the function template
2955/// will also be instantiated and the pointed-to value will be updated with
2956/// the instantiated function type.
2957///
2958/// \param Info if substitution fails for any reason, this object will be
2959/// populated with more information about the failure.
2960///
2961/// \returns TDK_Success if substitution was successful, or some failure
2962/// condition.
2963Sema::TemplateDeductionResult
2964Sema::SubstituteExplicitTemplateArguments(
2965 FunctionTemplateDecl *FunctionTemplate,
2966 TemplateArgumentListInfo &ExplicitTemplateArgs,
2967 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2968 SmallVectorImpl<QualType> &ParamTypes,
2969 QualType *FunctionType,
2970 TemplateDeductionInfo &Info) {
2971 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
2972 TemplateParameterList *TemplateParams
2973 = FunctionTemplate->getTemplateParameters();
2974
2975 if (ExplicitTemplateArgs.size() == 0) {
2976 // No arguments to substitute; just copy over the parameter types and
2977 // fill in the function type.
2978 for (auto P : Function->parameters())
2979 ParamTypes.push_back(P->getType());
2980
2981 if (FunctionType)
2982 *FunctionType = Function->getType();
2983 return TDK_Success;
2984 }
2985
2986 // Unevaluated SFINAE context.
2987 EnterExpressionEvaluationContext Unevaluated(
2988 *this, Sema::ExpressionEvaluationContext::Unevaluated);
2989 SFINAETrap Trap(*this);
2990
2991 // C++ [temp.arg.explicit]p3:
2992 // Template arguments that are present shall be specified in the
2993 // declaration order of their corresponding template-parameters. The
2994 // template argument list shall not specify more template-arguments than
2995 // there are corresponding template-parameters.
2996 SmallVector<TemplateArgument, 4> Builder;
2997
2998 // Enter a new template instantiation context where we check the
2999 // explicitly-specified template arguments against this function template,
3000 // and then substitute them into the function parameter types.
3001 SmallVector<TemplateArgument, 4> DeducedArgs;
3002 InstantiatingTemplate Inst(
3003 *this, Info.getLocation(), FunctionTemplate, DeducedArgs,
3004 CodeSynthesisContext::ExplicitTemplateArgumentSubstitution, Info);
3005 if (Inst.isInvalid())
3006 return TDK_InstantiationDepth;
3007
3008 if (CheckTemplateArgumentList(FunctionTemplate, SourceLocation(),
3009 ExplicitTemplateArgs, true, Builder, false) ||
3010 Trap.hasErrorOccurred()) {
3011 unsigned Index = Builder.size();
3012 if (Index >= TemplateParams->size())
3013 return TDK_SubstitutionFailure;
3014 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index));
3015 return TDK_InvalidExplicitArguments;
3016 }
3017
3018 // Form the template argument list from the explicitly-specified
3019 // template arguments.
3020 TemplateArgumentList *ExplicitArgumentList
3021 = TemplateArgumentList::CreateCopy(Context, Builder);
3022 Info.setExplicitArgs(ExplicitArgumentList);
3023
3024 // Template argument deduction and the final substitution should be
3025 // done in the context of the templated declaration. Explicit
3026 // argument substitution, on the other hand, needs to happen in the
3027 // calling context.
3028 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());
3029
3030 // If we deduced template arguments for a template parameter pack,
3031 // note that the template argument pack is partially substituted and record
3032 // the explicit template arguments. They'll be used as part of deduction
3033 // for this template parameter pack.
3034 unsigned PartiallySubstitutedPackIndex = -1u;
3035 if (!Builder.empty()) {
3036 const TemplateArgument &Arg = Builder.back();
3037 if (Arg.getKind() == TemplateArgument::Pack) {
3038 auto *Param = TemplateParams->getParam(Builder.size() - 1);
3039 // If this is a fully-saturated fixed-size pack, it should be
3040 // fully-substituted, not partially-substituted.
3041 Optional<unsigned> Expansions = getExpandedPackSize(Param);
3042 if (!Expansions || Arg.pack_size() < *Expansions) {
3043 PartiallySubstitutedPackIndex = Builder.size() - 1;
3044 CurrentInstantiationScope->SetPartiallySubstitutedPack(
3045 Param, Arg.pack_begin(), Arg.pack_size());
3046 }
3047 }
3048 }
3049
3050 const FunctionProtoType *Proto
3051 = Function->getType()->getAs<FunctionProtoType>();
3052 assert(Proto && "Function template does not have a prototype?")((Proto && "Function template does not have a prototype?"
) ? static_cast<void> (0) : __assert_fail ("Proto && \"Function template does not have a prototype?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3052, __PRETTY_FUNCTION__))
;
3053
3054 // Isolate our substituted parameters from our caller.
3055 LocalInstantiationScope InstScope(*this, /*MergeWithOuterScope*/true);
3056
3057 ExtParameterInfoBuilder ExtParamInfos;
3058
3059 // Instantiate the types of each of the function parameters given the
3060 // explicitly-specified template arguments. If the function has a trailing
3061 // return type, substitute it after the arguments to ensure we substitute
3062 // in lexical order.
3063 if (Proto->hasTrailingReturn()) {
3064 if (SubstParmTypes(Function->getLocation(), Function->parameters(),
3065 Proto->getExtParameterInfosOrNull(),
3066 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
3067 ParamTypes, /*params*/ nullptr, ExtParamInfos))
3068 return TDK_SubstitutionFailure;
3069 }
3070
3071 // Instantiate the return type.
3072 QualType ResultType;
3073 {
3074 // C++11 [expr.prim.general]p3:
3075 // If a declaration declares a member function or member function
3076 // template of a class X, the expression this is a prvalue of type
3077 // "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
3078 // and the end of the function-definition, member-declarator, or
3079 // declarator.
3080 Qualifiers ThisTypeQuals;
3081 CXXRecordDecl *ThisContext = nullptr;
3082 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
3083 ThisContext = Method->getParent();
3084 ThisTypeQuals = Method->getMethodQualifiers();
3085 }
3086
3087 CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals,
3088 getLangOpts().CPlusPlus11);
3089
3090 ResultType =
3091 SubstType(Proto->getReturnType(),
3092 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
3093 Function->getTypeSpecStartLoc(), Function->getDeclName());
3094 if (ResultType.isNull() || Trap.hasErrorOccurred())
3095 return TDK_SubstitutionFailure;
3096 // CUDA: Kernel function must have 'void' return type.
3097 if (getLangOpts().CUDA)
3098 if (Function->hasAttr<CUDAGlobalAttr>() && !ResultType->isVoidType()) {
3099 Diag(Function->getLocation(), diag::err_kern_type_not_void_return)
3100 << Function->getType() << Function->getSourceRange();
3101 return TDK_SubstitutionFailure;
3102 }
3103 }
3104
3105 // Instantiate the types of each of the function parameters given the
3106 // explicitly-specified template arguments if we didn't do so earlier.
3107 if (!Proto->hasTrailingReturn() &&
3108 SubstParmTypes(Function->getLocation(), Function->parameters(),
3109 Proto->getExtParameterInfosOrNull(),
3110 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
3111 ParamTypes, /*params*/ nullptr, ExtParamInfos))
3112 return TDK_SubstitutionFailure;
3113
3114 if (FunctionType) {
3115 auto EPI = Proto->getExtProtoInfo();
3116 EPI.ExtParameterInfos = ExtParamInfos.getPointerOrNull(ParamTypes.size());
3117
3118 // In C++1z onwards, exception specifications are part of the function type,
3119 // so substitution into the type must also substitute into the exception
3120 // specification.
3121 SmallVector<QualType, 4> ExceptionStorage;
3122 if (getLangOpts().CPlusPlus17 &&
3123 SubstExceptionSpec(
3124 Function->getLocation(), EPI.ExceptionSpec, ExceptionStorage,
3125 MultiLevelTemplateArgumentList(*ExplicitArgumentList)))
3126 return TDK_SubstitutionFailure;
3127
3128 *FunctionType = BuildFunctionType(ResultType, ParamTypes,
3129 Function->getLocation(),
3130 Function->getDeclName(),
3131 EPI);
3132 if (FunctionType->isNull() || Trap.hasErrorOccurred())
3133 return TDK_SubstitutionFailure;
3134 }
3135
3136 // C++ [temp.arg.explicit]p2:
3137 // Trailing template arguments that can be deduced (14.8.2) may be
3138 // omitted from the list of explicit template-arguments. If all of the
3139 // template arguments can be deduced, they may all be omitted; in this
3140 // case, the empty template argument list <> itself may also be omitted.
3141 //
3142 // Take all of the explicitly-specified arguments and put them into
3143 // the set of deduced template arguments. The partially-substituted
3144 // parameter pack, however, will be set to NULL since the deduction
3145 // mechanism handles the partially-substituted argument pack directly.
3146 Deduced.reserve(TemplateParams->size());
3147 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) {
3148 const TemplateArgument &Arg = ExplicitArgumentList->get(I);
3149 if (I == PartiallySubstitutedPackIndex)
3150 Deduced.push_back(DeducedTemplateArgument());
3151 else
3152 Deduced.push_back(Arg);
3153 }
3154
3155 return TDK_Success;
3156}
3157
3158/// Check whether the deduced argument type for a call to a function
3159/// template matches the actual argument type per C++ [temp.deduct.call]p4.
3160static Sema::TemplateDeductionResult
3161CheckOriginalCallArgDeduction(Sema &S, TemplateDeductionInfo &Info,
3162 Sema::OriginalCallArg OriginalArg,
3163 QualType DeducedA) {
3164 ASTContext &Context = S.Context;
3165
3166 auto Failed = [&]() -> Sema::TemplateDeductionResult {
3167 Info.FirstArg = TemplateArgument(DeducedA);
3168 Info.SecondArg = TemplateArgument(OriginalArg.OriginalArgType);
3169 Info.CallArgIndex = OriginalArg.ArgIdx;
3170 return OriginalArg.DecomposedParam ? Sema::TDK_DeducedMismatchNested
3171 : Sema::TDK_DeducedMismatch;
3172 };
3173
3174 QualType A = OriginalArg.OriginalArgType;
3175 QualType OriginalParamType = OriginalArg.OriginalParamType;
3176
3177 // Check for type equality (top-level cv-qualifiers are ignored).
3178 if (Context.hasSameUnqualifiedType(A, DeducedA))
3179 return Sema::TDK_Success;
3180
3181 // Strip off references on the argument types; they aren't needed for
3182 // the following checks.
3183 if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>())
3184 DeducedA = DeducedARef->getPointeeType();
3185 if (const ReferenceType *ARef = A->getAs<ReferenceType>())
3186 A = ARef->getPointeeType();
3187
3188 // C++ [temp.deduct.call]p4:
3189 // [...] However, there are three cases that allow a difference:
3190 // - If the original P is a reference type, the deduced A (i.e., the
3191 // type referred to by the reference) can be more cv-qualified than
3192 // the transformed A.
3193 if (const ReferenceType *OriginalParamRef
3194 = OriginalParamType->getAs<ReferenceType>()) {
3195 // We don't want to keep the reference around any more.
3196 OriginalParamType = OriginalParamRef->getPointeeType();
3197
3198 // FIXME: Resolve core issue (no number yet): if the original P is a
3199 // reference type and the transformed A is function type "noexcept F",
3200 // the deduced A can be F.
3201 QualType Tmp;
3202 if (A->isFunctionType() && S.IsFunctionConversion(A, DeducedA, Tmp))
3203 return Sema::TDK_Success;
3204
3205 Qualifiers AQuals = A.getQualifiers();
3206 Qualifiers DeducedAQuals = DeducedA.getQualifiers();
3207
3208 // Under Objective-C++ ARC, the deduced type may have implicitly
3209 // been given strong or (when dealing with a const reference)
3210 // unsafe_unretained lifetime. If so, update the original
3211 // qualifiers to include this lifetime.
3212 if (S.getLangOpts().ObjCAutoRefCount &&
3213 ((DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_Strong &&
3214 AQuals.getObjCLifetime() == Qualifiers::OCL_None) ||
3215 (DeducedAQuals.hasConst() &&
3216 DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone))) {
3217 AQuals.setObjCLifetime(DeducedAQuals.getObjCLifetime());
3218 }
3219
3220 if (AQuals == DeducedAQuals) {
3221 // Qualifiers match; there's nothing to do.
3222 } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) {
3223 return Failed();
3224 } else {
3225 // Qualifiers are compatible, so have the argument type adopt the
3226 // deduced argument type's qualifiers as if we had performed the
3227 // qualification conversion.
3228 A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals);
3229 }
3230 }
3231
3232 // - The transformed A can be another pointer or pointer to member
3233 // type that can be converted to the deduced A via a function pointer
3234 // conversion and/or a qualification conversion.
3235 //
3236 // Also allow conversions which merely strip __attribute__((noreturn)) from
3237 // function types (recursively).
3238 bool ObjCLifetimeConversion = false;
3239 QualType ResultTy;
3240 if ((A->isAnyPointerType() || A->isMemberPointerType()) &&
3241 (S.IsQualificationConversion(A, DeducedA, false,
3242 ObjCLifetimeConversion) ||
3243 S.IsFunctionConversion(A, DeducedA, ResultTy)))
3244 return Sema::TDK_Success;
3245
3246 // - If P is a class and P has the form simple-template-id, then the
3247 // transformed A can be a derived class of the deduced A. [...]
3248 // [...] Likewise, if P is a pointer to a class of the form
3249 // simple-template-id, the transformed A can be a pointer to a
3250 // derived class pointed to by the deduced A.
3251 if (const PointerType *OriginalParamPtr
3252 = OriginalParamType->getAs<PointerType>()) {
3253 if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) {
3254 if (const PointerType *APtr = A->getAs<PointerType>()) {
3255 if (A->getPointeeType()->isRecordType()) {
3256 OriginalParamType = OriginalParamPtr->getPointeeType();
3257 DeducedA = DeducedAPtr->getPointeeType();
3258 A = APtr->getPointeeType();
3259 }
3260 }
3261 }
3262 }
3263
3264 if (Context.hasSameUnqualifiedType(A, DeducedA))
3265 return Sema::TDK_Success;
3266
3267 if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) &&
3268 S.IsDerivedFrom(Info.getLocation(), A, DeducedA))
3269 return Sema::TDK_Success;
3270
3271 return Failed();
3272}
3273
3274/// Find the pack index for a particular parameter index in an instantiation of
3275/// a function template with specific arguments.
3276///
3277/// \return The pack index for whichever pack produced this parameter, or -1
3278/// if this was not produced by a parameter. Intended to be used as the
3279/// ArgumentPackSubstitutionIndex for further substitutions.
3280// FIXME: We should track this in OriginalCallArgs so we don't need to
3281// reconstruct it here.
3282static unsigned getPackIndexForParam(Sema &S,
3283 FunctionTemplateDecl *FunctionTemplate,
3284 const MultiLevelTemplateArgumentList &Args,
3285 unsigned ParamIdx) {
3286 unsigned Idx = 0;
3287 for (auto *PD : FunctionTemplate->getTemplatedDecl()->parameters()) {
3288 if (PD->isParameterPack()) {
3289 unsigned NumExpansions =
3290 S.getNumArgumentsInExpansion(PD->getType(), Args).getValueOr(1);
3291 if (Idx + NumExpansions > ParamIdx)
3292 return ParamIdx - Idx;
3293 Idx += NumExpansions;
3294 } else {
3295 if (Idx == ParamIdx)
3296 return -1; // Not a pack expansion
3297 ++Idx;
3298 }
3299 }
3300
3301 llvm_unreachable("parameter index would not be produced from template")::llvm::llvm_unreachable_internal("parameter index would not be produced from template"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3301)
;
3302}
3303
3304/// Finish template argument deduction for a function template,
3305/// checking the deduced template arguments for completeness and forming
3306/// the function template specialization.
3307///
3308/// \param OriginalCallArgs If non-NULL, the original call arguments against
3309/// which the deduced argument types should be compared.
3310Sema::TemplateDeductionResult Sema::FinishTemplateArgumentDeduction(
3311 FunctionTemplateDecl *FunctionTemplate,
3312 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3313 unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
3314 TemplateDeductionInfo &Info,
3315 SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
3316 bool PartialOverloading, llvm::function_ref<bool()> CheckNonDependent) {
3317 // Unevaluated SFINAE context.
3318 EnterExpressionEvaluationContext Unevaluated(
3319 *this, Sema::ExpressionEvaluationContext::Unevaluated);
3320 SFINAETrap Trap(*this);
3321
3322 // Enter a new template instantiation context while we instantiate the
3323 // actual function declaration.
3324 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
3325 InstantiatingTemplate Inst(
3326 *this, Info.getLocation(), FunctionTemplate, DeducedArgs,
3327 CodeSynthesisContext::DeducedTemplateArgumentSubstitution, Info);
3328 if (Inst.isInvalid())
3329 return TDK_InstantiationDepth;
3330
3331 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());
3332
3333 // C++ [temp.deduct.type]p2:
3334 // [...] or if any template argument remains neither deduced nor
3335 // explicitly specified, template argument deduction fails.
3336 SmallVector<TemplateArgument, 4> Builder;
3337 if (auto Result = ConvertDeducedTemplateArguments(
3338 *this, FunctionTemplate, /*IsDeduced*/true, Deduced, Info, Builder,
3339 CurrentInstantiationScope, NumExplicitlySpecified,
3340 PartialOverloading))
3341 return Result;
3342
3343 // C++ [temp.deduct.call]p10: [DR1391]
3344 // If deduction succeeds for all parameters that contain
3345 // template-parameters that participate in template argument deduction,
3346 // and all template arguments are explicitly specified, deduced, or
3347 // obtained from default template arguments, remaining parameters are then
3348 // compared with the corresponding arguments. For each remaining parameter
3349 // P with a type that was non-dependent before substitution of any
3350 // explicitly-specified template arguments, if the corresponding argument
3351 // A cannot be implicitly converted to P, deduction fails.
3352 if (CheckNonDependent())
3353 return TDK_NonDependentConversionFailure;
3354
3355 // Form the template argument list from the deduced template arguments.
3356 TemplateArgumentList *DeducedArgumentList
3357 = TemplateArgumentList::CreateCopy(Context, Builder);
3358 Info.reset(DeducedArgumentList);
3359
3360 // Substitute the deduced template arguments into the function template
3361 // declaration to produce the function template specialization.
3362 DeclContext *Owner = FunctionTemplate->getDeclContext();
3363 if (FunctionTemplate->getFriendObjectKind())
3364 Owner = FunctionTemplate->getLexicalDeclContext();
3365 MultiLevelTemplateArgumentList SubstArgs(*DeducedArgumentList);
3366 Specialization = cast_or_null<FunctionDecl>(
3367 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, SubstArgs));
3368 if (!Specialization || Specialization->isInvalidDecl())
3369 return TDK_SubstitutionFailure;
3370
3371 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() ==((Specialization->getPrimaryTemplate()->getCanonicalDecl
() == FunctionTemplate->getCanonicalDecl()) ? static_cast<
void> (0) : __assert_fail ("Specialization->getPrimaryTemplate()->getCanonicalDecl() == FunctionTemplate->getCanonicalDecl()"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3372, __PRETTY_FUNCTION__))
3372 FunctionTemplate->getCanonicalDecl())((Specialization->getPrimaryTemplate()->getCanonicalDecl
() == FunctionTemplate->getCanonicalDecl()) ? static_cast<
void> (0) : __assert_fail ("Specialization->getPrimaryTemplate()->getCanonicalDecl() == FunctionTemplate->getCanonicalDecl()"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 3372, __PRETTY_FUNCTION__))
;
3373
3374 // If the template argument list is owned by the function template
3375 // specialization, release it.
3376 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList &&
3377 !Trap.hasErrorOccurred())
3378 Info.take();
3379
3380 // There may have been an error that did not prevent us from constructing a
3381 // declaration. Mark the declaration invalid and return with a substitution
3382 // failure.
3383 if (Trap.hasErrorOccurred()) {
3384 Specialization->setInvalidDecl(true);
3385 return TDK_SubstitutionFailure;
3386 }
3387
3388 if (OriginalCallArgs) {
3389 // C++ [temp.deduct.call]p4:
3390 // In general, the deduction process attempts to find template argument
3391 // values that will make the deduced A identical to A (after the type A
3392 // is transformed as described above). [...]
3393 llvm::SmallDenseMap<std::pair<unsigned, QualType>, QualType> DeducedATypes;
3394 for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) {
3395 OriginalCallArg OriginalArg = (*OriginalCallArgs)[I];
3396
3397 auto ParamIdx = OriginalArg.ArgIdx;
3398 if (ParamIdx >= Specialization->getNumParams())
3399 // FIXME: This presumably means a pack ended up smaller than we
3400 // expected while deducing. Should this not result in deduction
3401 // failure? Can it even happen?
3402 continue;
3403
3404 QualType DeducedA;
3405 if (!OriginalArg.DecomposedParam) {
3406 // P is one of the function parameters, just look up its substituted
3407 // type.
3408 DeducedA = Specialization->getParamDecl(ParamIdx)->getType();
3409 } else {
3410 // P is a decomposed element of a parameter corresponding to a
3411 // braced-init-list argument. Substitute back into P to find the
3412 // deduced A.
3413 QualType &CacheEntry =
3414 DeducedATypes[{ParamIdx, OriginalArg.OriginalParamType}];
3415 if (CacheEntry.isNull()) {
3416 ArgumentPackSubstitutionIndexRAII PackIndex(
3417 *this, getPackIndexForParam(*this, FunctionTemplate, SubstArgs,
3418 ParamIdx));
3419 CacheEntry =
3420 SubstType(OriginalArg.OriginalParamType, SubstArgs,
3421 Specialization->getTypeSpecStartLoc(),
3422 Specialization->getDeclName());
3423 }
3424 DeducedA = CacheEntry;
3425 }
3426
3427 if (auto TDK =
3428 CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA))
3429 return TDK;
3430 }
3431 }
3432
3433 // If we suppressed any diagnostics while performing template argument
3434 // deduction, and if we haven't already instantiated this declaration,
3435 // keep track of these diagnostics. They'll be emitted if this specialization
3436 // is actually used.
3437 if (Info.diag_begin() != Info.diag_end()) {
3438 SuppressedDiagnosticsMap::iterator
3439 Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl());
3440 if (Pos == SuppressedDiagnostics.end())
3441 SuppressedDiagnostics[Specialization->getCanonicalDecl()]
3442 .append(Info.diag_begin(), Info.diag_end());
3443 }
3444
3445 return TDK_Success;
3446}
3447
3448/// Gets the type of a function for template-argument-deducton
3449/// purposes when it's considered as part of an overload set.
3450static QualType GetTypeOfFunction(Sema &S, const OverloadExpr::FindResult &R,
3451 FunctionDecl *Fn) {
3452 // We may need to deduce the return type of the function now.
3453 if (S.getLangOpts().CPlusPlus14 && Fn->getReturnType()->isUndeducedType() &&
3454 S.DeduceReturnType(Fn, R.Expression->getExprLoc(), /*Diagnose*/ false))
3455 return {};
3456
3457 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
3458 if (Method->isInstance()) {
3459 // An instance method that's referenced in a form that doesn't
3460 // look like a member pointer is just invalid.
3461 if (!R.HasFormOfMemberPointer)
3462 return {};
3463
3464 return S.Context.getMemberPointerType(Fn->getType(),
3465 S.Context.getTypeDeclType(Method->getParent()).getTypePtr());
3466 }
3467
3468 if (!R.IsAddressOfOperand) return Fn->getType();
3469 return S.Context.getPointerType(Fn->getType());
3470}
3471
3472/// Apply the deduction rules for overload sets.
3473///
3474/// \return the null type if this argument should be treated as an
3475/// undeduced context
3476static QualType
3477ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams,
3478 Expr *Arg, QualType ParamType,
3479 bool ParamWasReference) {
3480
3481 OverloadExpr::FindResult R = OverloadExpr::find(Arg);
3482
3483 OverloadExpr *Ovl = R.Expression;
3484
3485 // C++0x [temp.deduct.call]p4
3486 unsigned TDF = 0;
3487 if (ParamWasReference)
3488 TDF |= TDF_ParamWithReferenceType;
3489 if (R.IsAddressOfOperand)
3490 TDF |= TDF_IgnoreQualifiers;
3491
3492 // C++0x [temp.deduct.call]p6:
3493 // When P is a function type, pointer to function type, or pointer
3494 // to member function type:
3495
3496 if (!ParamType->isFunctionType() &&
3497 !ParamType->isFunctionPointerType() &&
3498 !ParamType->isMemberFunctionPointerType()) {
3499 if (Ovl->hasExplicitTemplateArgs()) {
3500 // But we can still look for an explicit specialization.
3501 if (FunctionDecl *ExplicitSpec
3502 = S.ResolveSingleFunctionTemplateSpecialization(Ovl))
3503 return GetTypeOfFunction(S, R, ExplicitSpec);
3504 }
3505
3506 DeclAccessPair DAP;
3507 if (FunctionDecl *Viable =
3508 S.resolveAddressOfOnlyViableOverloadCandidate(Arg, DAP))
3509 return GetTypeOfFunction(S, R, Viable);
3510
3511 return {};
3512 }
3513
3514 // Gather the explicit template arguments, if any.
3515 TemplateArgumentListInfo ExplicitTemplateArgs;
3516 if (Ovl->hasExplicitTemplateArgs())
3517 Ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
3518 QualType Match;
3519 for (UnresolvedSetIterator I = Ovl->decls_begin(),
3520 E = Ovl->decls_end(); I != E; ++I) {
3521 NamedDecl *D = (*I)->getUnderlyingDecl();
3522
3523 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) {
3524 // - If the argument is an overload set containing one or more
3525 // function templates, the parameter is treated as a
3526 // non-deduced context.
3527 if (!Ovl->hasExplicitTemplateArgs())
3528 return {};
3529
3530 // Otherwise, see if we can resolve a function type
3531 FunctionDecl *Specialization = nullptr;
3532 TemplateDeductionInfo Info(Ovl->getNameLoc());
3533 if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs,
3534 Specialization, Info))
3535 continue;
3536
3537 D = Specialization;
3538 }
3539
3540 FunctionDecl *Fn = cast<FunctionDecl>(D);
3541 QualType ArgType = GetTypeOfFunction(S, R, Fn);
3542 if (ArgType.isNull()) continue;
3543
3544 // Function-to-pointer conversion.
3545 if (!ParamWasReference && ParamType->isPointerType() &&
3546 ArgType->isFunctionType())
3547 ArgType = S.Context.getPointerType(ArgType);
3548
3549 // - If the argument is an overload set (not containing function
3550 // templates), trial argument deduction is attempted using each
3551 // of the members of the set. If deduction succeeds for only one
3552 // of the overload set members, that member is used as the
3553 // argument value for the deduction. If deduction succeeds for
3554 // more than one member of the overload set the parameter is
3555 // treated as a non-deduced context.
3556
3557 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2:
3558 // Type deduction is done independently for each P/A pair, and
3559 // the deduced template argument values are then combined.
3560 // So we do not reject deductions which were made elsewhere.
3561 SmallVector<DeducedTemplateArgument, 8>
3562 Deduced(TemplateParams->size());
3563 TemplateDeductionInfo Info(Ovl->getNameLoc());
3564 Sema::TemplateDeductionResult Result
3565 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
3566 ArgType, Info, Deduced, TDF);
3567 if (Result) continue;
3568 if (!Match.isNull())
3569 return {};
3570 Match = ArgType;
3571 }
3572
3573 return Match;
3574}
3575
3576/// Perform the adjustments to the parameter and argument types
3577/// described in C++ [temp.deduct.call].
3578///
3579/// \returns true if the caller should not attempt to perform any template
3580/// argument deduction based on this P/A pair because the argument is an
3581/// overloaded function set that could not be resolved.
3582static bool AdjustFunctionParmAndArgTypesForDeduction(
3583 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
3584 QualType &ParamType, QualType &ArgType, Expr *Arg, unsigned &TDF) {
3585 // C++0x [temp.deduct.call]p3:
3586 // If P is a cv-qualified type, the top level cv-qualifiers of P's type
3587 // are ignored for type deduction.
3588 if (ParamType.hasQualifiers())
3589 ParamType = ParamType.getUnqualifiedType();
3590
3591 // [...] If P is a reference type, the type referred to by P is
3592 // used for type deduction.
3593 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>();
3594 if (ParamRefType)
3595 ParamType = ParamRefType->getPointeeType();
3596
3597 // Overload sets usually make this parameter an undeduced context,
3598 // but there are sometimes special circumstances. Typically
3599 // involving a template-id-expr.
3600 if (ArgType == S.Context.OverloadTy) {
3601 ArgType = ResolveOverloadForDeduction(S, TemplateParams,
3602 Arg, ParamType,
3603 ParamRefType != nullptr);
3604 if (ArgType.isNull())
3605 return true;
3606 }
3607
3608 if (ParamRefType) {
3609 // If the argument has incomplete array type, try to complete its type.
3610 if (ArgType->isIncompleteArrayType()) {
3611 S.completeExprArrayBound(Arg);
3612 ArgType = Arg->getType();
3613 }
3614
3615 // C++1z [temp.deduct.call]p3:
3616 // If P is a forwarding reference and the argument is an lvalue, the type
3617 // "lvalue reference to A" is used in place of A for type deduction.
3618 if (isForwardingReference(QualType(ParamRefType, 0), FirstInnerIndex) &&
3619 Arg->isLValue())
3620 ArgType = S.Context.getLValueReferenceType(ArgType);
3621 } else {
3622 // C++ [temp.deduct.call]p2:
3623 // If P is not a reference type:
3624 // - If A is an array type, the pointer type produced by the
3625 // array-to-pointer standard conversion (4.2) is used in place of
3626 // A for type deduction; otherwise,
3627 if (ArgType->isArrayType())
3628 ArgType = S.Context.getArrayDecayedType(ArgType);
3629 // - If A is a function type, the pointer type produced by the
3630 // function-to-pointer standard conversion (4.3) is used in place
3631 // of A for type deduction; otherwise,
3632 else if (ArgType->isFunctionType())
3633 ArgType = S.Context.getPointerType(ArgType);
3634 else {
3635 // - If A is a cv-qualified type, the top level cv-qualifiers of A's
3636 // type are ignored for type deduction.
3637 ArgType = ArgType.getUnqualifiedType();
3638 }
3639 }
3640
3641 // C++0x [temp.deduct.call]p4:
3642 // In general, the deduction process attempts to find template argument
3643 // values that will make the deduced A identical to A (after the type A
3644 // is transformed as described above). [...]
3645 TDF = TDF_SkipNonDependent;
3646
3647 // - If the original P is a reference type, the deduced A (i.e., the
3648 // type referred to by the reference) can be more cv-qualified than
3649 // the transformed A.
3650 if (ParamRefType)
3651 TDF |= TDF_ParamWithReferenceType;
3652 // - The transformed A can be another pointer or pointer to member
3653 // type that can be converted to the deduced A via a qualification
3654 // conversion (4.4).
3655 if (ArgType->isPointerType() || ArgType->isMemberPointerType() ||
3656 ArgType->isObjCObjectPointerType())
3657 TDF |= TDF_IgnoreQualifiers;
3658 // - If P is a class and P has the form simple-template-id, then the
3659 // transformed A can be a derived class of the deduced A. Likewise,
3660 // if P is a pointer to a class of the form simple-template-id, the
3661 // transformed A can be a pointer to a derived class pointed to by
3662 // the deduced A.
3663 if (isSimpleTemplateIdType(ParamType) ||
3664 (isa<PointerType>(ParamType) &&
3665 isSimpleTemplateIdType(
3666 ParamType->getAs<PointerType>()->getPointeeType())))
3667 TDF |= TDF_DerivedClass;
3668
3669 return false;
3670}
3671
3672static bool
3673hasDeducibleTemplateParameters(Sema &S, FunctionTemplateDecl *FunctionTemplate,
3674 QualType T);
3675
3676static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument(
3677 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
3678 QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info,
3679 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3680 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs,
3681 bool DecomposedParam, unsigned ArgIdx, unsigned TDF);
3682
3683/// Attempt template argument deduction from an initializer list
3684/// deemed to be an argument in a function call.
3685static Sema::TemplateDeductionResult DeduceFromInitializerList(
3686 Sema &S, TemplateParameterList *TemplateParams, QualType AdjustedParamType,
3687 InitListExpr *ILE, TemplateDeductionInfo &Info,
3688 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3689 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs, unsigned ArgIdx,
3690 unsigned TDF) {
3691 // C++ [temp.deduct.call]p1: (CWG 1591)
3692 // If removing references and cv-qualifiers from P gives
3693 // std::initializer_list<P0> or P0[N] for some P0 and N and the argument is
3694 // a non-empty initializer list, then deduction is performed instead for
3695 // each element of the initializer list, taking P0 as a function template
3696 // parameter type and the initializer element as its argument
3697 //
3698 // We've already removed references and cv-qualifiers here.
3699 if (!ILE->getNumInits())
3700 return Sema::TDK_Success;
3701
3702 QualType ElTy;
3703 auto *ArrTy = S.Context.getAsArrayType(AdjustedParamType);
3704 if (ArrTy)
3705 ElTy = ArrTy->getElementType();
3706 else if (!S.isStdInitializerList(AdjustedParamType, &ElTy)) {
3707 // Otherwise, an initializer list argument causes the parameter to be
3708 // considered a non-deduced context
3709 return Sema::TDK_Success;
3710 }
3711
3712 // Resolving a core issue: a braced-init-list containing any designators is
3713 // a non-deduced context.
3714 for (Expr *E : ILE->inits())
3715 if (isa<DesignatedInitExpr>(E))
3716 return Sema::TDK_Success;
3717
3718 // Deduction only needs to be done for dependent types.
3719 if (ElTy->isDependentType()) {
3720 for (Expr *E : ILE->inits()) {
3721 if (auto Result = DeduceTemplateArgumentsFromCallArgument(
3722 S, TemplateParams, 0, ElTy, E, Info, Deduced, OriginalCallArgs, true,
3723 ArgIdx, TDF))
3724 return Result;
3725 }
3726 }
3727
3728 // in the P0[N] case, if N is a non-type template parameter, N is deduced
3729 // from the length of the initializer list.
3730 if (auto *DependentArrTy = dyn_cast_or_null<DependentSizedArrayType>(ArrTy)) {
3731 // Determine the array bound is something we can deduce.
3732 if (NonTypeTemplateParmDecl *NTTP =
3733 getDeducedParameterFromExpr(Info, DependentArrTy->getSizeExpr())) {
3734 // We can perform template argument deduction for the given non-type
3735 // template parameter.
3736 // C++ [temp.deduct.type]p13:
3737 // The type of N in the type T[N] is std::size_t.
3738 QualType T = S.Context.getSizeType();
3739 llvm::APInt Size(S.Context.getIntWidth(T), ILE->getNumInits());
3740 if (auto Result = DeduceNonTypeTemplateArgument(
3741 S, TemplateParams, NTTP, llvm::APSInt(Size), T,
3742 /*ArrayBound=*/true, Info, Deduced))
3743 return Result;
3744 }
3745 }
3746
3747 return Sema::TDK_Success;
3748}
3749
3750/// Perform template argument deduction per [temp.deduct.call] for a
3751/// single parameter / argument pair.
3752static Sema::TemplateDeductionResult DeduceTemplateArgumentsFromCallArgument(
3753 Sema &S, TemplateParameterList *TemplateParams, unsigned FirstInnerIndex,
3754 QualType ParamType, Expr *Arg, TemplateDeductionInfo &Info,
3755 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3756 SmallVectorImpl<Sema::OriginalCallArg> &OriginalCallArgs,
3757 bool DecomposedParam, unsigned ArgIdx, unsigned TDF) {
3758 QualType ArgType = Arg->getType();
3759 QualType OrigParamType = ParamType;
3760
3761 // If P is a reference type [...]
3762 // If P is a cv-qualified type [...]
3763 if (AdjustFunctionParmAndArgTypesForDeduction(
3764 S, TemplateParams, FirstInnerIndex, ParamType, ArgType, Arg, TDF))
3765 return Sema::TDK_Success;
3766
3767 // If [...] the argument is a non-empty initializer list [...]
3768 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg))
3769 return DeduceFromInitializerList(S, TemplateParams, ParamType, ILE, Info,
3770 Deduced, OriginalCallArgs, ArgIdx, TDF);
3771
3772 // [...] the deduction process attempts to find template argument values
3773 // that will make the deduced A identical to A
3774 //
3775 // Keep track of the argument type and corresponding parameter index,
3776 // so we can check for compatibility between the deduced A and A.
3777 OriginalCallArgs.push_back(
3778 Sema::OriginalCallArg(OrigParamType, DecomposedParam, ArgIdx, ArgType));
3779 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
3780 ArgType, Info, Deduced, TDF);
3781}
3782
3783/// Perform template argument deduction from a function call
3784/// (C++ [temp.deduct.call]).
3785///
3786/// \param FunctionTemplate the function template for which we are performing
3787/// template argument deduction.
3788///
3789/// \param ExplicitTemplateArgs the explicit template arguments provided
3790/// for this call.
3791///
3792/// \param Args the function call arguments
3793///
3794/// \param Specialization if template argument deduction was successful,
3795/// this will be set to the function template specialization produced by
3796/// template argument deduction.
3797///
3798/// \param Info the argument will be updated to provide additional information
3799/// about template argument deduction.
3800///
3801/// \param CheckNonDependent A callback to invoke to check conversions for
3802/// non-dependent parameters, between deduction and substitution, per DR1391.
3803/// If this returns true, substitution will be skipped and we return
3804/// TDK_NonDependentConversionFailure. The callback is passed the parameter
3805/// types (after substituting explicit template arguments).
3806///
3807/// \returns the result of template argument deduction.
3808Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
3809 FunctionTemplateDecl *FunctionTemplate,
3810 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
3811 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
3812 bool PartialOverloading,
3813 llvm::function_ref<bool(ArrayRef<QualType>)> CheckNonDependent) {
3814 if (FunctionTemplate->isInvalidDecl())
3815 return TDK_Invalid;
3816
3817 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
3818 unsigned NumParams = Function->getNumParams();
3819
3820 unsigned FirstInnerIndex = getFirstInnerIndex(FunctionTemplate);
3821
3822 // C++ [temp.deduct.call]p1:
3823 // Template argument deduction is done by comparing each function template
3824 // parameter type (call it P) with the type of the corresponding argument
3825 // of the call (call it A) as described below.
3826 if (Args.size() < Function->getMinRequiredArguments() && !PartialOverloading)
3827 return TDK_TooFewArguments;
3828 else if (TooManyArguments(NumParams, Args.size(), PartialOverloading)) {
3829 const FunctionProtoType *Proto
3830 = Function->getType()->getAs<FunctionProtoType>();
3831 if (Proto->isTemplateVariadic())
3832 /* Do nothing */;
3833 else if (!Proto->isVariadic())
3834 return TDK_TooManyArguments;
3835 }
3836
3837 // The types of the parameters from which we will perform template argument
3838 // deduction.
3839 LocalInstantiationScope InstScope(*this);
3840 TemplateParameterList *TemplateParams
3841 = FunctionTemplate->getTemplateParameters();
3842 SmallVector<DeducedTemplateArgument, 4> Deduced;
3843 SmallVector<QualType, 8> ParamTypes;
3844 unsigned NumExplicitlySpecified = 0;
3845 if (ExplicitTemplateArgs) {
3846 TemplateDeductionResult Result =
3847 SubstituteExplicitTemplateArguments(FunctionTemplate,
3848 *ExplicitTemplateArgs,
3849 Deduced,
3850 ParamTypes,
3851 nullptr,
3852 Info);
3853 if (Result)
3854 return Result;
3855
3856 NumExplicitlySpecified = Deduced.size();
3857 } else {
3858 // Just fill in the parameter types from the function declaration.
3859 for (unsigned I = 0; I != NumParams; ++I)
3860 ParamTypes.push_back(Function->getParamDecl(I)->getType());
3861 }
3862
3863 SmallVector<OriginalCallArg, 8> OriginalCallArgs;
3864
3865 // Deduce an argument of type ParamType from an expression with index ArgIdx.
3866 auto DeduceCallArgument = [&](QualType ParamType, unsigned ArgIdx) {
3867 // C++ [demp.deduct.call]p1: (DR1391)
3868 // Template argument deduction is done by comparing each function template
3869 // parameter that contains template-parameters that participate in
3870 // template argument deduction ...
3871 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType))
3872 return Sema::TDK_Success;
3873
3874 // ... with the type of the corresponding argument
3875 return DeduceTemplateArgumentsFromCallArgument(
3876 *this, TemplateParams, FirstInnerIndex, ParamType, Args[ArgIdx], Info, Deduced,
3877 OriginalCallArgs, /*Decomposed*/false, ArgIdx, /*TDF*/ 0);
3878 };
3879
3880 // Deduce template arguments from the function parameters.
3881 Deduced.resize(TemplateParams->size());
3882 SmallVector<QualType, 8> ParamTypesForArgChecking;
3883 for (unsigned ParamIdx = 0, NumParamTypes = ParamTypes.size(), ArgIdx = 0;
3884 ParamIdx != NumParamTypes; ++ParamIdx) {
3885 QualType ParamType = ParamTypes[ParamIdx];
3886
3887 const PackExpansionType *ParamExpansion =
3888 dyn_cast<PackExpansionType>(ParamType);
3889 if (!ParamExpansion) {
3890 // Simple case: matching a function parameter to a function argument.
3891 if (ArgIdx >= Args.size())
3892 break;
3893
3894 ParamTypesForArgChecking.push_back(ParamType);
3895 if (auto Result = DeduceCallArgument(ParamType, ArgIdx++))
3896 return Result;
3897
3898 continue;
3899 }
3900
3901 QualType ParamPattern = ParamExpansion->getPattern();
3902 PackDeductionScope PackScope(*this, TemplateParams, Deduced, Info,
3903 ParamPattern);
3904
3905 // C++0x [temp.deduct.call]p1:
3906 // For a function parameter pack that occurs at the end of the
3907 // parameter-declaration-list, the type A of each remaining argument of
3908 // the call is compared with the type P of the declarator-id of the
3909 // function parameter pack. Each comparison deduces template arguments
3910 // for subsequent positions in the template parameter packs expanded by
3911 // the function parameter pack. When a function parameter pack appears
3912 // in a non-deduced context [not at the end of the list], the type of
3913 // that parameter pack is never deduced.
3914 //
3915 // FIXME: The above rule allows the size of the parameter pack to change
3916 // after we skip it (in the non-deduced case). That makes no sense, so
3917 // we instead notionally deduce the pack against N arguments, where N is
3918 // the length of the explicitly-specified pack if it's expanded by the
3919 // parameter pack and 0 otherwise, and we treat each deduction as a
3920 // non-deduced context.
3921 if (ParamIdx + 1 == NumParamTypes || PackScope.hasFixedArity()) {
3922 for (; ArgIdx < Args.size() && PackScope.hasNextElement();
3923 PackScope.nextPackElement(), ++ArgIdx) {
3924 ParamTypesForArgChecking.push_back(ParamPattern);
3925 if (auto Result = DeduceCallArgument(ParamPattern, ArgIdx))
3926 return Result;
3927 }
3928 } else {
3929 // If the parameter type contains an explicitly-specified pack that we
3930 // could not expand, skip the number of parameters notionally created
3931 // by the expansion.
3932 Optional<unsigned> NumExpansions = ParamExpansion->getNumExpansions();
3933 if (NumExpansions && !PackScope.isPartiallyExpanded()) {
3934 for (unsigned I = 0; I != *NumExpansions && ArgIdx < Args.size();
3935 ++I, ++ArgIdx) {
3936 ParamTypesForArgChecking.push_back(ParamPattern);
3937 // FIXME: Should we add OriginalCallArgs for these? What if the
3938 // corresponding argument is a list?
3939 PackScope.nextPackElement();
3940 }
3941 }
3942 }
3943
3944 // Build argument packs for each of the parameter packs expanded by this
3945 // pack expansion.
3946 if (auto Result = PackScope.finish())
3947 return Result;
3948 }
3949
3950 // Capture the context in which the function call is made. This is the context
3951 // that is needed when the accessibility of template arguments is checked.
3952 DeclContext *CallingCtx = CurContext;
3953
3954 return FinishTemplateArgumentDeduction(
3955 FunctionTemplate, Deduced, NumExplicitlySpecified, Specialization, Info,
3956 &OriginalCallArgs, PartialOverloading, [&, CallingCtx]() {
3957 ContextRAII SavedContext(*this, CallingCtx);
3958 return CheckNonDependent(ParamTypesForArgChecking);
3959 });
3960}
3961
3962QualType Sema::adjustCCAndNoReturn(QualType ArgFunctionType,
3963 QualType FunctionType,
3964 bool AdjustExceptionSpec) {
3965 if (ArgFunctionType.isNull())
3966 return ArgFunctionType;
3967
3968 const FunctionProtoType *FunctionTypeP =
3969 FunctionType->castAs<FunctionProtoType>();
3970 const FunctionProtoType *ArgFunctionTypeP =
3971 ArgFunctionType->getAs<FunctionProtoType>();
3972
3973 FunctionProtoType::ExtProtoInfo EPI = ArgFunctionTypeP->getExtProtoInfo();
3974 bool Rebuild = false;
3975
3976 CallingConv CC = FunctionTypeP->getCallConv();
3977 if (EPI.ExtInfo.getCC() != CC) {
3978 EPI.ExtInfo = EPI.ExtInfo.withCallingConv(CC);
3979 Rebuild = true;
3980 }
3981
3982 bool NoReturn = FunctionTypeP->getNoReturnAttr();
3983 if (EPI.ExtInfo.getNoReturn() != NoReturn) {
3984 EPI.ExtInfo = EPI.ExtInfo.withNoReturn(NoReturn);
3985 Rebuild = true;
3986 }
3987
3988 if (AdjustExceptionSpec && (FunctionTypeP->hasExceptionSpec() ||
3989 ArgFunctionTypeP->hasExceptionSpec())) {
3990 EPI.ExceptionSpec = FunctionTypeP->getExtProtoInfo().ExceptionSpec;
3991 Rebuild = true;
3992 }
3993
3994 if (!Rebuild)
3995 return ArgFunctionType;
3996
3997 return Context.getFunctionType(ArgFunctionTypeP->getReturnType(),
3998 ArgFunctionTypeP->getParamTypes(), EPI);
3999}
4000
4001/// Deduce template arguments when taking the address of a function
4002/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
4003/// a template.
4004///
4005/// \param FunctionTemplate the function template for which we are performing
4006/// template argument deduction.
4007///
4008/// \param ExplicitTemplateArgs the explicitly-specified template
4009/// arguments.
4010///
4011/// \param ArgFunctionType the function type that will be used as the
4012/// "argument" type (A) when performing template argument deduction from the
4013/// function template's function type. This type may be NULL, if there is no
4014/// argument type to compare against, in C++0x [temp.arg.explicit]p3.
4015///
4016/// \param Specialization if template argument deduction was successful,
4017/// this will be set to the function template specialization produced by
4018/// template argument deduction.
4019///
4020/// \param Info the argument will be updated to provide additional information
4021/// about template argument deduction.
4022///
4023/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
4024/// the address of a function template per [temp.deduct.funcaddr] and
4025/// [over.over]. If \c false, we are looking up a function template
4026/// specialization based on its signature, per [temp.deduct.decl].
4027///
4028/// \returns the result of template argument deduction.
4029Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
4030 FunctionTemplateDecl *FunctionTemplate,
4031 TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType,
4032 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
4033 bool IsAddressOfFunction) {
4034 if (FunctionTemplate->isInvalidDecl())
4035 return TDK_Invalid;
4036
4037 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
4038 TemplateParameterList *TemplateParams
4039 = FunctionTemplate->getTemplateParameters();
4040 QualType FunctionType = Function->getType();
4041
4042 // Substitute any explicit template arguments.
4043 LocalInstantiationScope InstScope(*this);
4044 SmallVector<DeducedTemplateArgument, 4> Deduced;
4045 unsigned NumExplicitlySpecified = 0;
4046 SmallVector<QualType, 4> ParamTypes;
4047 if (ExplicitTemplateArgs) {
4048 if (TemplateDeductionResult Result
4049 = SubstituteExplicitTemplateArguments(FunctionTemplate,
4050 *ExplicitTemplateArgs,
4051 Deduced, ParamTypes,
4052 &FunctionType, Info))
4053 return Result;
4054
4055 NumExplicitlySpecified = Deduced.size();
4056 }
4057
4058 // When taking the address of a function, we require convertibility of
4059 // the resulting function type. Otherwise, we allow arbitrary mismatches
4060 // of calling convention and noreturn.
4061 if (!IsAddressOfFunction)
4062 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, FunctionType,
4063 /*AdjustExceptionSpec*/false);
4064
4065 // Unevaluated SFINAE context.
4066 EnterExpressionEvaluationContext Unevaluated(
4067 *this, Sema::ExpressionEvaluationContext::Unevaluated);
4068 SFINAETrap Trap(*this);
4069
4070 Deduced.resize(TemplateParams->size());
4071
4072 // If the function has a deduced return type, substitute it for a dependent
4073 // type so that we treat it as a non-deduced context in what follows. If we
4074 // are looking up by signature, the signature type should also have a deduced
4075 // return type, which we instead expect to exactly match.
4076 bool HasDeducedReturnType = false;
4077 if (getLangOpts().CPlusPlus14 && IsAddressOfFunction &&
4078 Function->getReturnType()->getContainedAutoType()) {
4079 FunctionType = SubstAutoType(FunctionType, Context.DependentTy);
4080 HasDeducedReturnType = true;
4081 }
4082
4083 if (!ArgFunctionType.isNull()) {
4084 unsigned TDF =
4085 TDF_TopLevelParameterTypeList | TDF_AllowCompatibleFunctionType;
4086 // Deduce template arguments from the function type.
4087 if (TemplateDeductionResult Result
4088 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
4089 FunctionType, ArgFunctionType,
4090 Info, Deduced, TDF))
4091 return Result;
4092 }
4093
4094 if (TemplateDeductionResult Result
4095 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced,
4096 NumExplicitlySpecified,
4097 Specialization, Info))
4098 return Result;
4099
4100 // If the function has a deduced return type, deduce it now, so we can check
4101 // that the deduced function type matches the requested type.
4102 if (HasDeducedReturnType &&
4103 Specialization->getReturnType()->isUndeducedType() &&
4104 DeduceReturnType(Specialization, Info.getLocation(), false))
4105 return TDK_MiscellaneousDeductionFailure;
4106
4107 // If the function has a dependent exception specification, resolve it now,
4108 // so we can check that the exception specification matches.
4109 auto *SpecializationFPT =
4110 Specialization->getType()->castAs<FunctionProtoType>();
4111 if (getLangOpts().CPlusPlus17 &&
4112 isUnresolvedExceptionSpec(SpecializationFPT->getExceptionSpecType()) &&
4113 !ResolveExceptionSpec(Info.getLocation(), SpecializationFPT))
4114 return TDK_MiscellaneousDeductionFailure;
4115
4116 // Adjust the exception specification of the argument to match the
4117 // substituted and resolved type we just formed. (Calling convention and
4118 // noreturn can't be dependent, so we don't actually need this for them
4119 // right now.)
4120 QualType SpecializationType = Specialization->getType();
4121 if (!IsAddressOfFunction)
4122 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, SpecializationType,
4123 /*AdjustExceptionSpec*/true);
4124
4125 // If the requested function type does not match the actual type of the
4126 // specialization with respect to arguments of compatible pointer to function
4127 // types, template argument deduction fails.
4128 if (!ArgFunctionType.isNull()) {
4129 if (IsAddressOfFunction &&
4130 !isSameOrCompatibleFunctionType(
4131 Context.getCanonicalType(SpecializationType),
4132 Context.getCanonicalType(ArgFunctionType)))
4133 return TDK_MiscellaneousDeductionFailure;
4134
4135 if (!IsAddressOfFunction &&
4136 !Context.hasSameType(SpecializationType, ArgFunctionType))
4137 return TDK_MiscellaneousDeductionFailure;
4138 }
4139
4140 return TDK_Success;
4141}
4142
4143/// Deduce template arguments for a templated conversion
4144/// function (C++ [temp.deduct.conv]) and, if successful, produce a
4145/// conversion function template specialization.
4146Sema::TemplateDeductionResult
4147Sema::DeduceTemplateArguments(FunctionTemplateDecl *ConversionTemplate,
4148 QualType ToType,
4149 CXXConversionDecl *&Specialization,
4150 TemplateDeductionInfo &Info) {
4151 if (ConversionTemplate->isInvalidDecl())
4152 return TDK_Invalid;
4153
4154 CXXConversionDecl *ConversionGeneric
4155 = cast<CXXConversionDecl>(ConversionTemplate->getTemplatedDecl());
4156
4157 QualType FromType = ConversionGeneric->getConversionType();
4158
4159 // Canonicalize the types for deduction.
4160 QualType P = Context.getCanonicalType(FromType);
4161 QualType A = Context.getCanonicalType(ToType);
4162
4163 // C++0x [temp.deduct.conv]p2:
4164 // If P is a reference type, the type referred to by P is used for
4165 // type deduction.
4166 if (const ReferenceType *PRef = P->getAs<ReferenceType>())
4167 P = PRef->getPointeeType();
4168
4169 // C++0x [temp.deduct.conv]p4:
4170 // [...] If A is a reference type, the type referred to by A is used
4171 // for type deduction.
4172 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) {
4173 A = ARef->getPointeeType();
4174 // We work around a defect in the standard here: cv-qualifiers are also
4175 // removed from P and A in this case, unless P was a reference type. This
4176 // seems to mostly match what other compilers are doing.
4177 if (!FromType->getAs<ReferenceType>()) {
4178 A = A.getUnqualifiedType();
4179 P = P.getUnqualifiedType();
4180 }
4181
4182 // C++ [temp.deduct.conv]p3:
4183 //
4184 // If A is not a reference type:
4185 } else {
4186 assert(!A->isReferenceType() && "Reference types were handled above")((!A->isReferenceType() && "Reference types were handled above"
) ? static_cast<void> (0) : __assert_fail ("!A->isReferenceType() && \"Reference types were handled above\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4186, __PRETTY_FUNCTION__))
;
4187
4188 // - If P is an array type, the pointer type produced by the
4189 // array-to-pointer standard conversion (4.2) is used in place
4190 // of P for type deduction; otherwise,
4191 if (P->isArrayType())
4192 P = Context.getArrayDecayedType(P);
4193 // - If P is a function type, the pointer type produced by the
4194 // function-to-pointer standard conversion (4.3) is used in
4195 // place of P for type deduction; otherwise,
4196 else if (P->isFunctionType())
4197 P = Context.getPointerType(P);
4198 // - If P is a cv-qualified type, the top level cv-qualifiers of
4199 // P's type are ignored for type deduction.
4200 else
4201 P = P.getUnqualifiedType();
4202
4203 // C++0x [temp.deduct.conv]p4:
4204 // If A is a cv-qualified type, the top level cv-qualifiers of A's
4205 // type are ignored for type deduction. If A is a reference type, the type
4206 // referred to by A is used for type deduction.
4207 A = A.getUnqualifiedType();
4208 }
4209
4210 // Unevaluated SFINAE context.
4211 EnterExpressionEvaluationContext Unevaluated(
4212 *this, Sema::ExpressionEvaluationContext::Unevaluated);
4213 SFINAETrap Trap(*this);
4214
4215 // C++ [temp.deduct.conv]p1:
4216 // Template argument deduction is done by comparing the return
4217 // type of the template conversion function (call it P) with the
4218 // type that is required as the result of the conversion (call it
4219 // A) as described in 14.8.2.4.
4220 TemplateParameterList *TemplateParams
4221 = ConversionTemplate->getTemplateParameters();
4222 SmallVector<DeducedTemplateArgument, 4> Deduced;
4223 Deduced.resize(TemplateParams->size());
4224
4225 // C++0x [temp.deduct.conv]p4:
4226 // In general, the deduction process attempts to find template
4227 // argument values that will make the deduced A identical to
4228 // A. However, there are two cases that allow a difference:
4229 unsigned TDF = 0;
4230 // - If the original A is a reference type, A can be more
4231 // cv-qualified than the deduced A (i.e., the type referred to
4232 // by the reference)
4233 if (ToType->isReferenceType())
4234 TDF |= TDF_ArgWithReferenceType;
4235 // - The deduced A can be another pointer or pointer to member
4236 // type that can be converted to A via a qualification
4237 // conversion.
4238 //
4239 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when
4240 // both P and A are pointers or member pointers. In this case, we
4241 // just ignore cv-qualifiers completely).
4242 if ((P->isPointerType() && A->isPointerType()) ||
4243 (P->isMemberPointerType() && A->isMemberPointerType()))
4244 TDF |= TDF_IgnoreQualifiers;
4245 if (TemplateDeductionResult Result
4246 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
4247 P, A, Info, Deduced, TDF))
4248 return Result;
4249
4250 // Create an Instantiation Scope for finalizing the operator.
4251 LocalInstantiationScope InstScope(*this);
4252 // Finish template argument deduction.
4253 FunctionDecl *ConversionSpecialized = nullptr;
4254 TemplateDeductionResult Result
4255 = FinishTemplateArgumentDeduction(ConversionTemplate, Deduced, 0,
4256 ConversionSpecialized, Info);
4257 Specialization = cast_or_null<CXXConversionDecl>(ConversionSpecialized);
4258 return Result;
4259}
4260
4261/// Deduce template arguments for a function template when there is
4262/// nothing to deduce against (C++0x [temp.arg.explicit]p3).
4263///
4264/// \param FunctionTemplate the function template for which we are performing
4265/// template argument deduction.
4266///
4267/// \param ExplicitTemplateArgs the explicitly-specified template
4268/// arguments.
4269///
4270/// \param Specialization if template argument deduction was successful,
4271/// this will be set to the function template specialization produced by
4272/// template argument deduction.
4273///
4274/// \param Info the argument will be updated to provide additional information
4275/// about template argument deduction.
4276///
4277/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
4278/// the address of a function template in a context where we do not have a
4279/// target type, per [over.over]. If \c false, we are looking up a function
4280/// template specialization based on its signature, which only happens when
4281/// deducing a function parameter type from an argument that is a template-id
4282/// naming a function template specialization.
4283///
4284/// \returns the result of template argument deduction.
4285Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
4286 FunctionTemplateDecl *FunctionTemplate,
4287 TemplateArgumentListInfo *ExplicitTemplateArgs,
4288 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
4289 bool IsAddressOfFunction) {
4290 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs,
4291 QualType(), Specialization, Info,
4292 IsAddressOfFunction);
4293}
4294
4295namespace {
4296 struct DependentAuto { bool IsPack; };
4297
4298 /// Substitute the 'auto' specifier or deduced template specialization type
4299 /// specifier within a type for a given replacement type.
4300 class SubstituteDeducedTypeTransform :
4301 public TreeTransform<SubstituteDeducedTypeTransform> {
4302 QualType Replacement;
4303 bool ReplacementIsPack;
4304 bool UseTypeSugar;
4305
4306 public:
4307 SubstituteDeducedTypeTransform(Sema &SemaRef, DependentAuto DA)
4308 : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef), Replacement(),
4309 ReplacementIsPack(DA.IsPack), UseTypeSugar(true) {}
4310
4311 SubstituteDeducedTypeTransform(Sema &SemaRef, QualType Replacement,
4312 bool UseTypeSugar = true)
4313 : TreeTransform<SubstituteDeducedTypeTransform>(SemaRef),
4314 Replacement(Replacement), ReplacementIsPack(false),
4315 UseTypeSugar(UseTypeSugar) {}
4316
4317 QualType TransformDesugared(TypeLocBuilder &TLB, DeducedTypeLoc TL) {
4318 assert(isa<TemplateTypeParmType>(Replacement) &&((isa<TemplateTypeParmType>(Replacement) && "unexpected unsugared replacement kind"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateTypeParmType>(Replacement) && \"unexpected unsugared replacement kind\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4319, __PRETTY_FUNCTION__))
4319 "unexpected unsugared replacement kind")((isa<TemplateTypeParmType>(Replacement) && "unexpected unsugared replacement kind"
) ? static_cast<void> (0) : __assert_fail ("isa<TemplateTypeParmType>(Replacement) && \"unexpected unsugared replacement kind\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4319, __PRETTY_FUNCTION__))
;
4320 QualType Result = Replacement;
4321 TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
4322 NewTL.setNameLoc(TL.getNameLoc());
4323 return Result;
4324 }
4325
4326 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) {
4327 // If we're building the type pattern to deduce against, don't wrap the
4328 // substituted type in an AutoType. Certain template deduction rules
4329 // apply only when a template type parameter appears directly (and not if
4330 // the parameter is found through desugaring). For instance:
4331 // auto &&lref = lvalue;
4332 // must transform into "rvalue reference to T" not "rvalue reference to
4333 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply.
4334 //
4335 // FIXME: Is this still necessary?
4336 if (!UseTypeSugar)
4337 return TransformDesugared(TLB, TL);
4338
4339 QualType Result = SemaRef.Context.getAutoType(
4340 Replacement, TL.getTypePtr()->getKeyword(), Replacement.isNull(),
4341 ReplacementIsPack);
4342 auto NewTL = TLB.push<AutoTypeLoc>(Result);
4343 NewTL.setNameLoc(TL.getNameLoc());
4344 return Result;
4345 }
4346
4347 QualType TransformDeducedTemplateSpecializationType(
4348 TypeLocBuilder &TLB, DeducedTemplateSpecializationTypeLoc TL) {
4349 if (!UseTypeSugar)
4350 return TransformDesugared(TLB, TL);
4351
4352 QualType Result = SemaRef.Context.getDeducedTemplateSpecializationType(
4353 TL.getTypePtr()->getTemplateName(),
4354 Replacement, Replacement.isNull());
4355 auto NewTL = TLB.push<DeducedTemplateSpecializationTypeLoc>(Result);
4356 NewTL.setNameLoc(TL.getNameLoc());
4357 return Result;
4358 }
4359
4360 ExprResult TransformLambdaExpr(LambdaExpr *E) {
4361 // Lambdas never need to be transformed.
4362 return E;
4363 }
4364
4365 QualType Apply(TypeLoc TL) {
4366 // Create some scratch storage for the transformed type locations.
4367 // FIXME: We're just going to throw this information away. Don't build it.
4368 TypeLocBuilder TLB;
4369 TLB.reserve(TL.getFullDataSize());
4370 return TransformType(TLB, TL);
4371 }
4372 };
4373
4374} // namespace
4375
4376Sema::DeduceAutoResult
4377Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, QualType &Result,
4378 Optional<unsigned> DependentDeductionDepth) {
4379 return DeduceAutoType(Type->getTypeLoc(), Init, Result,
4380 DependentDeductionDepth);
4381}
4382
4383/// Attempt to produce an informative diagostic explaining why auto deduction
4384/// failed.
4385/// \return \c true if diagnosed, \c false if not.
4386static bool diagnoseAutoDeductionFailure(Sema &S,
4387 Sema::TemplateDeductionResult TDK,
4388 TemplateDeductionInfo &Info,
4389 ArrayRef<SourceRange> Ranges) {
4390 switch (TDK) {
4391 case Sema::TDK_Inconsistent: {
4392 // Inconsistent deduction means we were deducing from an initializer list.
4393 auto D = S.Diag(Info.getLocation(), diag::err_auto_inconsistent_deduction);
4394 D << Info.FirstArg << Info.SecondArg;
4395 for (auto R : Ranges)
4396 D << R;
4397 return true;
4398 }
4399
4400 // FIXME: Are there other cases for which a custom diagnostic is more useful
4401 // than the basic "types don't match" diagnostic?
4402
4403 default:
4404 return false;
4405 }
4406}
4407
4408/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
4409///
4410/// Note that this is done even if the initializer is dependent. (This is
4411/// necessary to support partial ordering of templates using 'auto'.)
4412/// A dependent type will be produced when deducing from a dependent type.
4413///
4414/// \param Type the type pattern using the auto type-specifier.
4415/// \param Init the initializer for the variable whose type is to be deduced.
4416/// \param Result if type deduction was successful, this will be set to the
4417/// deduced type.
4418/// \param DependentDeductionDepth Set if we should permit deduction in
4419/// dependent cases. This is necessary for template partial ordering with
4420/// 'auto' template parameters. The value specified is the template
4421/// parameter depth at which we should perform 'auto' deduction.
4422Sema::DeduceAutoResult
4423Sema::DeduceAutoType(TypeLoc Type, Expr *&Init, QualType &Result,
4424 Optional<unsigned> DependentDeductionDepth) {
4425 if (Init->getType()->isNonOverloadPlaceholderType()) {
4426 ExprResult NonPlaceholder = CheckPlaceholderExpr(Init);
4427 if (NonPlaceholder.isInvalid())
4428 return DAR_FailedAlreadyDiagnosed;
4429 Init = NonPlaceholder.get();
4430 }
4431
4432 DependentAuto DependentResult = {
4433 /*.IsPack = */ (bool)Type.getAs<PackExpansionTypeLoc>()};
4434
4435 if (!DependentDeductionDepth &&
4436 (Type.getType()->isDependentType() || Init->isTypeDependent())) {
4437 Result = SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type);
4438 assert(!Result.isNull() && "substituting DependentTy can't fail")((!Result.isNull() && "substituting DependentTy can't fail"
) ? static_cast<void> (0) : __assert_fail ("!Result.isNull() && \"substituting DependentTy can't fail\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4438, __PRETTY_FUNCTION__))
;
4439 return DAR_Succeeded;
4440 }
4441
4442 // Find the depth of template parameter to synthesize.
4443 unsigned Depth = DependentDeductionDepth.getValueOr(0);
4444
4445 // If this is a 'decltype(auto)' specifier, do the decltype dance.
4446 // Since 'decltype(auto)' can only occur at the top of the type, we
4447 // don't need to go digging for it.
4448 if (const AutoType *AT = Type.getType()->getAs<AutoType>()) {
4449 if (AT->isDecltypeAuto()) {
4450 if (isa<InitListExpr>(Init)) {
4451 Diag(Init->getBeginLoc(), diag::err_decltype_auto_initializer_list);
4452 return DAR_FailedAlreadyDiagnosed;
4453 }
4454
4455 ExprResult ER = CheckPlaceholderExpr(Init);
4456 if (ER.isInvalid())
4457 return DAR_FailedAlreadyDiagnosed;
4458 Init = ER.get();
4459 QualType Deduced = BuildDecltypeType(Init, Init->getBeginLoc(), false);
4460 if (Deduced.isNull())
4461 return DAR_FailedAlreadyDiagnosed;
4462 // FIXME: Support a non-canonical deduced type for 'auto'.
4463 Deduced = Context.getCanonicalType(Deduced);
4464 Result = SubstituteDeducedTypeTransform(*this, Deduced).Apply(Type);
4465 if (Result.isNull())
4466 return DAR_FailedAlreadyDiagnosed;
4467 return DAR_Succeeded;
4468 } else if (!getLangOpts().CPlusPlus) {
4469 if (isa<InitListExpr>(Init)) {
4470 Diag(Init->getBeginLoc(), diag::err_auto_init_list_from_c);
4471 return DAR_FailedAlreadyDiagnosed;
4472 }
4473 }
4474 }
4475
4476 SourceLocation Loc = Init->getExprLoc();
4477
4478 LocalInstantiationScope InstScope(*this);
4479
4480 // Build template<class TemplParam> void Func(FuncParam);
4481 TemplateTypeParmDecl *TemplParam = TemplateTypeParmDecl::Create(
4482 Context, nullptr, SourceLocation(), Loc, Depth, 0, nullptr, false, false);
4483 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0);
4484 NamedDecl *TemplParamPtr = TemplParam;
4485 FixedSizeTemplateParameterListStorage<1, false> TemplateParamsSt(
4486 Loc, Loc, TemplParamPtr, Loc, nullptr);
4487
4488 QualType FuncParam =
4489 SubstituteDeducedTypeTransform(*this, TemplArg, /*UseTypeSugar*/false)
4490 .Apply(Type);
4491 assert(!FuncParam.isNull() &&((!FuncParam.isNull() && "substituting template parameter for 'auto' failed"
) ? static_cast<void> (0) : __assert_fail ("!FuncParam.isNull() && \"substituting template parameter for 'auto' failed\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4492, __PRETTY_FUNCTION__))
4492 "substituting template parameter for 'auto' failed")((!FuncParam.isNull() && "substituting template parameter for 'auto' failed"
) ? static_cast<void> (0) : __assert_fail ("!FuncParam.isNull() && \"substituting template parameter for 'auto' failed\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4492, __PRETTY_FUNCTION__))
;
4493
4494 // Deduce type of TemplParam in Func(Init)
4495 SmallVector<DeducedTemplateArgument, 1> Deduced;
4496 Deduced.resize(1);
4497
4498 TemplateDeductionInfo Info(Loc, Depth);
4499
4500 // If deduction failed, don't diagnose if the initializer is dependent; it
4501 // might acquire a matching type in the instantiation.
4502 auto DeductionFailed = [&](TemplateDeductionResult TDK,
4503 ArrayRef<SourceRange> Ranges) -> DeduceAutoResult {
4504 if (Init->isTypeDependent()) {
4505 Result =
4506 SubstituteDeducedTypeTransform(*this, DependentResult).Apply(Type);
4507 assert(!Result.isNull() && "substituting DependentTy can't fail")((!Result.isNull() && "substituting DependentTy can't fail"
) ? static_cast<void> (0) : __assert_fail ("!Result.isNull() && \"substituting DependentTy can't fail\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4507, __PRETTY_FUNCTION__))
;
4508 return DAR_Succeeded;
4509 }
4510 if (diagnoseAutoDeductionFailure(*this, TDK, Info, Ranges))
4511 return DAR_FailedAlreadyDiagnosed;
4512 return DAR_Failed;
4513 };
4514
4515 SmallVector<OriginalCallArg, 4> OriginalCallArgs;
4516
4517 InitListExpr *InitList = dyn_cast<InitListExpr>(Init);
4518 if (InitList) {
4519 // Notionally, we substitute std::initializer_list<T> for 'auto' and deduce
4520 // against that. Such deduction only succeeds if removing cv-qualifiers and
4521 // references results in std::initializer_list<T>.
4522 if (!Type.getType().getNonReferenceType()->getAs<AutoType>())
4523 return DAR_Failed;
4524
4525 // Resolving a core issue: a braced-init-list containing any designators is
4526 // a non-deduced context.
4527 for (Expr *E : InitList->inits())
4528 if (isa<DesignatedInitExpr>(E))
4529 return DAR_Failed;
4530
4531 SourceRange DeducedFromInitRange;
4532 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) {
4533 Expr *Init = InitList->getInit(i);
4534
4535 if (auto TDK = DeduceTemplateArgumentsFromCallArgument(
4536 *this, TemplateParamsSt.get(), 0, TemplArg, Init,
4537 Info, Deduced, OriginalCallArgs, /*Decomposed*/ true,
4538 /*ArgIdx*/ 0, /*TDF*/ 0))
4539 return DeductionFailed(TDK, {DeducedFromInitRange,
4540 Init->getSourceRange()});
4541
4542 if (DeducedFromInitRange.isInvalid() &&
4543 Deduced[0].getKind() != TemplateArgument::Null)
4544 DeducedFromInitRange = Init->getSourceRange();
4545 }
4546 } else {
4547 if (!getLangOpts().CPlusPlus && Init->refersToBitField()) {
4548 Diag(Loc, diag::err_auto_bitfield);
4549 return DAR_FailedAlreadyDiagnosed;
4550 }
4551
4552 if (auto TDK = DeduceTemplateArgumentsFromCallArgument(
4553 *this, TemplateParamsSt.get(), 0, FuncParam, Init, Info, Deduced,
4554 OriginalCallArgs, /*Decomposed*/ false, /*ArgIdx*/ 0, /*TDF*/ 0))
4555 return DeductionFailed(TDK, {});
4556 }
4557
4558 // Could be null if somehow 'auto' appears in a non-deduced context.
4559 if (Deduced[0].getKind() != TemplateArgument::Type)
4560 return DeductionFailed(TDK_Incomplete, {});
4561
4562 QualType DeducedType = Deduced[0].getAsType();
4563
4564 if (InitList) {
4565 DeducedType = BuildStdInitializerList(DeducedType, Loc);
4566 if (DeducedType.isNull())
4567 return DAR_FailedAlreadyDiagnosed;
4568 }
4569
4570 Result = SubstituteDeducedTypeTransform(*this, DeducedType).Apply(Type);
4571 if (Result.isNull())
4572 return DAR_FailedAlreadyDiagnosed;
4573
4574 // Check that the deduced argument type is compatible with the original
4575 // argument type per C++ [temp.deduct.call]p4.
4576 QualType DeducedA = InitList ? Deduced[0].getAsType() : Result;
4577 for (const OriginalCallArg &OriginalArg : OriginalCallArgs) {
4578 assert((bool)InitList == OriginalArg.DecomposedParam &&(((bool)InitList == OriginalArg.DecomposedParam && "decomposed non-init-list in auto deduction?"
) ? static_cast<void> (0) : __assert_fail ("(bool)InitList == OriginalArg.DecomposedParam && \"decomposed non-init-list in auto deduction?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4579, __PRETTY_FUNCTION__))
4579 "decomposed non-init-list in auto deduction?")(((bool)InitList == OriginalArg.DecomposedParam && "decomposed non-init-list in auto deduction?"
) ? static_cast<void> (0) : __assert_fail ("(bool)InitList == OriginalArg.DecomposedParam && \"decomposed non-init-list in auto deduction?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4579, __PRETTY_FUNCTION__))
;
4580 if (auto TDK =
4581 CheckOriginalCallArgDeduction(*this, Info, OriginalArg, DeducedA)) {
4582 Result = QualType();
4583 return DeductionFailed(TDK, {});
4584 }
4585 }
4586
4587 return DAR_Succeeded;
4588}
4589
4590QualType Sema::SubstAutoType(QualType TypeWithAuto,
4591 QualType TypeToReplaceAuto) {
4592 if (TypeToReplaceAuto->isDependentType())
4593 return SubstituteDeducedTypeTransform(
4594 *this, DependentAuto{
4595 TypeToReplaceAuto->containsUnexpandedParameterPack()})
4596 .TransformType(TypeWithAuto);
4597 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto)
4598 .TransformType(TypeWithAuto);
4599}
4600
4601TypeSourceInfo *Sema::SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
4602 QualType TypeToReplaceAuto) {
4603 if (TypeToReplaceAuto->isDependentType())
4604 return SubstituteDeducedTypeTransform(
4605 *this,
4606 DependentAuto{
4607 TypeToReplaceAuto->containsUnexpandedParameterPack()})
4608 .TransformType(TypeWithAuto);
4609 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto)
4610 .TransformType(TypeWithAuto);
4611}
4612
4613QualType Sema::ReplaceAutoType(QualType TypeWithAuto,
4614 QualType TypeToReplaceAuto) {
4615 return SubstituteDeducedTypeTransform(*this, TypeToReplaceAuto,
1
Calling 'TreeTransform::TransformType'
4616 /*UseTypeSugar*/ false)
4617 .TransformType(TypeWithAuto);
4618}
4619
4620void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) {
4621 if (isa<InitListExpr>(Init))
4622 Diag(VDecl->getLocation(),
4623 VDecl->isInitCapture()
4624 ? diag::err_init_capture_deduction_failure_from_init_list
4625 : diag::err_auto_var_deduction_failure_from_init_list)
4626 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange();
4627 else
4628 Diag(VDecl->getLocation(),
4629 VDecl->isInitCapture() ? diag::err_init_capture_deduction_failure
4630 : diag::err_auto_var_deduction_failure)
4631 << VDecl->getDeclName() << VDecl->getType() << Init->getType()
4632 << Init->getSourceRange();
4633}
4634
4635bool Sema::DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
4636 bool Diagnose) {
4637 assert(FD->getReturnType()->isUndeducedType())((FD->getReturnType()->isUndeducedType()) ? static_cast
<void> (0) : __assert_fail ("FD->getReturnType()->isUndeducedType()"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4637, __PRETTY_FUNCTION__))
;
4638
4639 // For a lambda's conversion operator, deduce any 'auto' or 'decltype(auto)'
4640 // within the return type from the call operator's type.
4641 if (isLambdaConversionOperator(FD)) {
4642 CXXRecordDecl *Lambda = cast<CXXMethodDecl>(FD)->getParent();
4643 FunctionDecl *CallOp = Lambda->getLambdaCallOperator();
4644
4645 // For a generic lambda, instantiate the call operator if needed.
4646 if (auto *Args = FD->getTemplateSpecializationArgs()) {
4647 CallOp = InstantiateFunctionDeclaration(
4648 CallOp->getDescribedFunctionTemplate(), Args, Loc);
4649 if (!CallOp || CallOp->isInvalidDecl())
4650 return true;
4651
4652 // We might need to deduce the return type by instantiating the definition
4653 // of the operator() function.
4654 if (CallOp->getReturnType()->isUndeducedType()) {
4655 runWithSufficientStackSpace(Loc, [&] {
4656 InstantiateFunctionDefinition(Loc, CallOp);
4657 });
4658 }
4659 }
4660
4661 if (CallOp->isInvalidDecl())
4662 return true;
4663 assert(!CallOp->getReturnType()->isUndeducedType() &&((!CallOp->getReturnType()->isUndeducedType() &&
"failed to deduce lambda return type") ? static_cast<void
> (0) : __assert_fail ("!CallOp->getReturnType()->isUndeducedType() && \"failed to deduce lambda return type\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4664, __PRETTY_FUNCTION__))
4664 "failed to deduce lambda return type")((!CallOp->getReturnType()->isUndeducedType() &&
"failed to deduce lambda return type") ? static_cast<void
> (0) : __assert_fail ("!CallOp->getReturnType()->isUndeducedType() && \"failed to deduce lambda return type\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4664, __PRETTY_FUNCTION__))
;
4665
4666 // Build the new return type from scratch.
4667 QualType RetType = getLambdaConversionFunctionResultType(
4668 CallOp->getType()->castAs<FunctionProtoType>());
4669 if (FD->getReturnType()->getAs<PointerType>())
4670 RetType = Context.getPointerType(RetType);
4671 else {
4672 assert(FD->getReturnType()->getAs<BlockPointerType>())((FD->getReturnType()->getAs<BlockPointerType>())
? static_cast<void> (0) : __assert_fail ("FD->getReturnType()->getAs<BlockPointerType>()"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4672, __PRETTY_FUNCTION__))
;
4673 RetType = Context.getBlockPointerType(RetType);
4674 }
4675 Context.adjustDeducedFunctionResultType(FD, RetType);
4676 return false;
4677 }
4678
4679 if (FD->getTemplateInstantiationPattern()) {
4680 runWithSufficientStackSpace(Loc, [&] {
4681 InstantiateFunctionDefinition(Loc, FD);
4682 });
4683 }
4684
4685 bool StillUndeduced = FD->getReturnType()->isUndeducedType();
4686 if (StillUndeduced && Diagnose && !FD->isInvalidDecl()) {
4687 Diag(Loc, diag::err_auto_fn_used_before_defined) << FD;
4688 Diag(FD->getLocation(), diag::note_callee_decl) << FD;
4689 }
4690
4691 return StillUndeduced;
4692}
4693
4694/// If this is a non-static member function,
4695static void
4696AddImplicitObjectParameterType(ASTContext &Context,
4697 CXXMethodDecl *Method,
4698 SmallVectorImpl<QualType> &ArgTypes) {
4699 // C++11 [temp.func.order]p3:
4700 // [...] The new parameter is of type "reference to cv A," where cv are
4701 // the cv-qualifiers of the function template (if any) and A is
4702 // the class of which the function template is a member.
4703 //
4704 // The standard doesn't say explicitly, but we pick the appropriate kind of
4705 // reference type based on [over.match.funcs]p4.
4706 QualType ArgTy = Context.getTypeDeclType(Method->getParent());
4707 ArgTy = Context.getQualifiedType(ArgTy, Method->getMethodQualifiers());
4708 if (Method->getRefQualifier() == RQ_RValue)
4709 ArgTy = Context.getRValueReferenceType(ArgTy);
4710 else
4711 ArgTy = Context.getLValueReferenceType(ArgTy);
4712 ArgTypes.push_back(ArgTy);
4713}
4714
4715/// Determine whether the function template \p FT1 is at least as
4716/// specialized as \p FT2.
4717static bool isAtLeastAsSpecializedAs(Sema &S,
4718 SourceLocation Loc,
4719 FunctionTemplateDecl *FT1,
4720 FunctionTemplateDecl *FT2,
4721 TemplatePartialOrderingContext TPOC,
4722 unsigned NumCallArguments1) {
4723 FunctionDecl *FD1 = FT1->getTemplatedDecl();
4724 FunctionDecl *FD2 = FT2->getTemplatedDecl();
4725 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>();
4726 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>();
4727
4728 assert(Proto1 && Proto2 && "Function templates must have prototypes")((Proto1 && Proto2 && "Function templates must have prototypes"
) ? static_cast<void> (0) : __assert_fail ("Proto1 && Proto2 && \"Function templates must have prototypes\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4728, __PRETTY_FUNCTION__))
;
4729 TemplateParameterList *TemplateParams = FT2->getTemplateParameters();
4730 SmallVector<DeducedTemplateArgument, 4> Deduced;
4731 Deduced.resize(TemplateParams->size());
4732
4733 // C++0x [temp.deduct.partial]p3:
4734 // The types used to determine the ordering depend on the context in which
4735 // the partial ordering is done:
4736 TemplateDeductionInfo Info(Loc);
4737 SmallVector<QualType, 4> Args2;
4738 switch (TPOC) {
4739 case TPOC_Call: {
4740 // - In the context of a function call, the function parameter types are
4741 // used.
4742 CXXMethodDecl *Method1 = dyn_cast<CXXMethodDecl>(FD1);
4743 CXXMethodDecl *Method2 = dyn_cast<CXXMethodDecl>(FD2);
4744
4745 // C++11 [temp.func.order]p3:
4746 // [...] If only one of the function templates is a non-static
4747 // member, that function template is considered to have a new
4748 // first parameter inserted in its function parameter list. The
4749 // new parameter is of type "reference to cv A," where cv are
4750 // the cv-qualifiers of the function template (if any) and A is
4751 // the class of which the function template is a member.
4752 //
4753 // Note that we interpret this to mean "if one of the function
4754 // templates is a non-static member and the other is a non-member";
4755 // otherwise, the ordering rules for static functions against non-static
4756 // functions don't make any sense.
4757 //
4758 // C++98/03 doesn't have this provision but we've extended DR532 to cover
4759 // it as wording was broken prior to it.
4760 SmallVector<QualType, 4> Args1;
4761
4762 unsigned NumComparedArguments = NumCallArguments1;
4763
4764 if (!Method2 && Method1 && !Method1->isStatic()) {
4765 // Compare 'this' from Method1 against first parameter from Method2.
4766 AddImplicitObjectParameterType(S.Context, Method1, Args1);
4767 ++NumComparedArguments;
4768 } else if (!Method1 && Method2 && !Method2->isStatic()) {
4769 // Compare 'this' from Method2 against first parameter from Method1.
4770 AddImplicitObjectParameterType(S.Context, Method2, Args2);
4771 }
4772
4773 Args1.insert(Args1.end(), Proto1->param_type_begin(),
4774 Proto1->param_type_end());
4775 Args2.insert(Args2.end(), Proto2->param_type_begin(),
4776 Proto2->param_type_end());
4777
4778 // C++ [temp.func.order]p5:
4779 // The presence of unused ellipsis and default arguments has no effect on
4780 // the partial ordering of function templates.
4781 if (Args1.size() > NumComparedArguments)
4782 Args1.resize(NumComparedArguments);
4783 if (Args2.size() > NumComparedArguments)
4784 Args2.resize(NumComparedArguments);
4785 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(),
4786 Args1.data(), Args1.size(), Info, Deduced,
4787 TDF_None, /*PartialOrdering=*/true))
4788 return false;
4789
4790 break;
4791 }
4792
4793 case TPOC_Conversion:
4794 // - In the context of a call to a conversion operator, the return types
4795 // of the conversion function templates are used.
4796 if (DeduceTemplateArgumentsByTypeMatch(
4797 S, TemplateParams, Proto2->getReturnType(), Proto1->getReturnType(),
4798 Info, Deduced, TDF_None,
4799 /*PartialOrdering=*/true))
4800 return false;
4801 break;
4802
4803 case TPOC_Other:
4804 // - In other contexts (14.6.6.2) the function template's function type
4805 // is used.
4806 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
4807 FD2->getType(), FD1->getType(),
4808 Info, Deduced, TDF_None,
4809 /*PartialOrdering=*/true))
4810 return false;
4811 break;
4812 }
4813
4814 // C++0x [temp.deduct.partial]p11:
4815 // In most cases, all template parameters must have values in order for
4816 // deduction to succeed, but for partial ordering purposes a template
4817 // parameter may remain without a value provided it is not used in the
4818 // types being used for partial ordering. [ Note: a template parameter used
4819 // in a non-deduced context is considered used. -end note]
4820 unsigned ArgIdx = 0, NumArgs = Deduced.size();
4821 for (; ArgIdx != NumArgs; ++ArgIdx)
4822 if (Deduced[ArgIdx].isNull())
4823 break;
4824
4825 // FIXME: We fail to implement [temp.deduct.type]p1 along this path. We need
4826 // to substitute the deduced arguments back into the template and check that
4827 // we get the right type.
4828
4829 if (ArgIdx == NumArgs) {
4830 // All template arguments were deduced. FT1 is at least as specialized
4831 // as FT2.
4832 return true;
4833 }
4834
4835 // Figure out which template parameters were used.
4836 llvm::SmallBitVector UsedParameters(TemplateParams->size());
4837 switch (TPOC) {
4838 case TPOC_Call:
4839 for (unsigned I = 0, N = Args2.size(); I != N; ++I)
4840 ::MarkUsedTemplateParameters(S.Context, Args2[I], false,
4841 TemplateParams->getDepth(),
4842 UsedParameters);
4843 break;
4844
4845 case TPOC_Conversion:
4846 ::MarkUsedTemplateParameters(S.Context, Proto2->getReturnType(), false,
4847 TemplateParams->getDepth(), UsedParameters);
4848 break;
4849
4850 case TPOC_Other:
4851 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false,
4852 TemplateParams->getDepth(),
4853 UsedParameters);
4854 break;
4855 }
4856
4857 for (; ArgIdx != NumArgs; ++ArgIdx)
4858 // If this argument had no value deduced but was used in one of the types
4859 // used for partial ordering, then deduction fails.
4860 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx])
4861 return false;
4862
4863 return true;
4864}
4865
4866/// Determine whether this a function template whose parameter-type-list
4867/// ends with a function parameter pack.
4868static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) {
4869 FunctionDecl *Function = FunTmpl->getTemplatedDecl();
4870 unsigned NumParams = Function->getNumParams();
4871 if (NumParams == 0)
4872 return false;
4873
4874 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1);
4875 if (!Last->isParameterPack())
4876 return false;
4877
4878 // Make sure that no previous parameter is a parameter pack.
4879 while (--NumParams > 0) {
4880 if (Function->getParamDecl(NumParams - 1)->isParameterPack())
4881 return false;
4882 }
4883
4884 return true;
4885}
4886
4887/// Returns the more specialized function template according
4888/// to the rules of function template partial ordering (C++ [temp.func.order]).
4889///
4890/// \param FT1 the first function template
4891///
4892/// \param FT2 the second function template
4893///
4894/// \param TPOC the context in which we are performing partial ordering of
4895/// function templates.
4896///
4897/// \param NumCallArguments1 The number of arguments in the call to FT1, used
4898/// only when \c TPOC is \c TPOC_Call.
4899///
4900/// \param NumCallArguments2 The number of arguments in the call to FT2, used
4901/// only when \c TPOC is \c TPOC_Call.
4902///
4903/// \returns the more specialized function template. If neither
4904/// template is more specialized, returns NULL.
4905FunctionTemplateDecl *
4906Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1,
4907 FunctionTemplateDecl *FT2,
4908 SourceLocation Loc,
4909 TemplatePartialOrderingContext TPOC,
4910 unsigned NumCallArguments1,
4911 unsigned NumCallArguments2) {
4912 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC,
4913 NumCallArguments1);
4914 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC,
4915 NumCallArguments2);
4916
4917 if (Better1 != Better2) // We have a clear winner
4918 return Better1 ? FT1 : FT2;
4919
4920 if (!Better1 && !Better2) // Neither is better than the other
4921 return nullptr;
4922
4923 // FIXME: This mimics what GCC implements, but doesn't match up with the
4924 // proposed resolution for core issue 692. This area needs to be sorted out,
4925 // but for now we attempt to maintain compatibility.
4926 bool Variadic1 = isVariadicFunctionTemplate(FT1);
4927 bool Variadic2 = isVariadicFunctionTemplate(FT2);
4928 if (Variadic1 != Variadic2)
4929 return Variadic1? FT2 : FT1;
4930
4931 return nullptr;
4932}
4933
4934/// Determine if the two templates are equivalent.
4935static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) {
4936 if (T1 == T2)
4937 return true;
4938
4939 if (!T1 || !T2)
4940 return false;
4941
4942 return T1->getCanonicalDecl() == T2->getCanonicalDecl();
4943}
4944
4945/// Retrieve the most specialized of the given function template
4946/// specializations.
4947///
4948/// \param SpecBegin the start iterator of the function template
4949/// specializations that we will be comparing.
4950///
4951/// \param SpecEnd the end iterator of the function template
4952/// specializations, paired with \p SpecBegin.
4953///
4954/// \param Loc the location where the ambiguity or no-specializations
4955/// diagnostic should occur.
4956///
4957/// \param NoneDiag partial diagnostic used to diagnose cases where there are
4958/// no matching candidates.
4959///
4960/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
4961/// occurs.
4962///
4963/// \param CandidateDiag partial diagnostic used for each function template
4964/// specialization that is a candidate in the ambiguous ordering. One parameter
4965/// in this diagnostic should be unbound, which will correspond to the string
4966/// describing the template arguments for the function template specialization.
4967///
4968/// \returns the most specialized function template specialization, if
4969/// found. Otherwise, returns SpecEnd.
4970UnresolvedSetIterator Sema::getMostSpecialized(
4971 UnresolvedSetIterator SpecBegin, UnresolvedSetIterator SpecEnd,
4972 TemplateSpecCandidateSet &FailedCandidates,
4973 SourceLocation Loc, const PartialDiagnostic &NoneDiag,
4974 const PartialDiagnostic &AmbigDiag, const PartialDiagnostic &CandidateDiag,
4975 bool Complain, QualType TargetType) {
4976 if (SpecBegin == SpecEnd) {
4977 if (Complain) {
4978 Diag(Loc, NoneDiag);
4979 FailedCandidates.NoteCandidates(*this, Loc);
4980 }
4981 return SpecEnd;
4982 }
4983
4984 if (SpecBegin + 1 == SpecEnd)
4985 return SpecBegin;
4986
4987 // Find the function template that is better than all of the templates it
4988 // has been compared to.
4989 UnresolvedSetIterator Best = SpecBegin;
4990 FunctionTemplateDecl *BestTemplate
4991 = cast<FunctionDecl>(*Best)->getPrimaryTemplate();
4992 assert(BestTemplate && "Not a function template specialization?")((BestTemplate && "Not a function template specialization?"
) ? static_cast<void> (0) : __assert_fail ("BestTemplate && \"Not a function template specialization?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4992, __PRETTY_FUNCTION__))
;
4993 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) {
4994 FunctionTemplateDecl *Challenger
4995 = cast<FunctionDecl>(*I)->getPrimaryTemplate();
4996 assert(Challenger && "Not a function template specialization?")((Challenger && "Not a function template specialization?"
) ? static_cast<void> (0) : __assert_fail ("Challenger && \"Not a function template specialization?\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 4996, __PRETTY_FUNCTION__))
;
4997 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
4998 Loc, TPOC_Other, 0, 0),
4999 Challenger)) {
5000 Best = I;
5001 BestTemplate = Challenger;
5002 }
5003 }
5004
5005 // Make sure that the "best" function template is more specialized than all
5006 // of the others.
5007 bool Ambiguous = false;
5008 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
5009 FunctionTemplateDecl *Challenger
5010 = cast<FunctionDecl>(*I)->getPrimaryTemplate();
5011 if (I != Best &&
5012 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
5013 Loc, TPOC_Other, 0, 0),
5014 BestTemplate)) {
5015 Ambiguous = true;
5016 break;
5017 }
5018 }
5019
5020 if (!Ambiguous) {
5021 // We found an answer. Return it.
5022 return Best;
5023 }
5024
5025 // Diagnose the ambiguity.
5026 if (Complain) {
5027 Diag(Loc, AmbigDiag);
5028
5029 // FIXME: Can we order the candidates in some sane way?
5030 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
5031 PartialDiagnostic PD = CandidateDiag;
5032 const auto *FD = cast<FunctionDecl>(*I);
5033 PD << FD << getTemplateArgumentBindingsText(
5034 FD->getPrimaryTemplate()->getTemplateParameters(),
5035 *FD->getTemplateSpecializationArgs());
5036 if (!TargetType.isNull())
5037 HandleFunctionTypeMismatch(PD, FD->getType(), TargetType);
5038 Diag((*I)->getLocation(), PD);
5039 }
5040 }
5041
5042 return SpecEnd;
5043}
5044
5045/// Determine whether one partial specialization, P1, is at least as
5046/// specialized than another, P2.
5047///
5048/// \tparam TemplateLikeDecl The kind of P2, which must be a
5049/// TemplateDecl or {Class,Var}TemplatePartialSpecializationDecl.
5050/// \param T1 The injected-class-name of P1 (faked for a variable template).
5051/// \param T2 The injected-class-name of P2 (faked for a variable template).
5052template<typename TemplateLikeDecl>
5053static bool isAtLeastAsSpecializedAs(Sema &S, QualType T1, QualType T2,
5054 TemplateLikeDecl *P2,
5055 TemplateDeductionInfo &Info) {
5056 // C++ [temp.class.order]p1:
5057 // For two class template partial specializations, the first is at least as
5058 // specialized as the second if, given the following rewrite to two
5059 // function templates, the first function template is at least as
5060 // specialized as the second according to the ordering rules for function
5061 // templates (14.6.6.2):
5062 // - the first function template has the same template parameters as the
5063 // first partial specialization and has a single function parameter
5064 // whose type is a class template specialization with the template
5065 // arguments of the first partial specialization, and
5066 // - the second function template has the same template parameters as the
5067 // second partial specialization and has a single function parameter
5068 // whose type is a class template specialization with the template
5069 // arguments of the second partial specialization.
5070 //
5071 // Rather than synthesize function templates, we merely perform the
5072 // equivalent partial ordering by performing deduction directly on
5073 // the template arguments of the class template partial
5074 // specializations. This computation is slightly simpler than the
5075 // general problem of function template partial ordering, because
5076 // class template partial specializations are more constrained. We
5077 // know that every template parameter is deducible from the class
5078 // template partial specialization's template arguments, for
5079 // example.
5080 SmallVector<DeducedTemplateArgument, 4> Deduced;
5081
5082 // Determine whether P1 is at least as specialized as P2.
5083 Deduced.resize(P2->getTemplateParameters()->size());
5084 if (DeduceTemplateArgumentsByTypeMatch(S, P2->getTemplateParameters(),
5085 T2, T1, Info, Deduced, TDF_None,
5086 /*PartialOrdering=*/true))
5087 return false;
5088
5089 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),
5090 Deduced.end());
5091 Sema::InstantiatingTemplate Inst(S, Info.getLocation(), P2, DeducedArgs,
5092 Info);
5093 auto *TST1 = T1->castAs<TemplateSpecializationType>();
5094 if (FinishTemplateArgumentDeduction(
5095 S, P2, /*IsPartialOrdering=*/true,
5096 TemplateArgumentList(TemplateArgumentList::OnStack,
5097 TST1->template_arguments()),
5098 Deduced, Info))
5099 return false;
5100
5101 return true;
5102}
5103
5104/// Returns the more specialized class template partial specialization
5105/// according to the rules of partial ordering of class template partial
5106/// specializations (C++ [temp.class.order]).
5107///
5108/// \param PS1 the first class template partial specialization
5109///
5110/// \param PS2 the second class template partial specialization
5111///
5112/// \returns the more specialized class template partial specialization. If
5113/// neither partial specialization is more specialized, returns NULL.
5114ClassTemplatePartialSpecializationDecl *
5115Sema::getMoreSpecializedPartialSpecialization(
5116 ClassTemplatePartialSpecializationDecl *PS1,
5117 ClassTemplatePartialSpecializationDecl *PS2,
5118 SourceLocation Loc) {
5119 QualType PT1 = PS1->getInjectedSpecializationType();
5120 QualType PT2 = PS2->getInjectedSpecializationType();
5121
5122 TemplateDeductionInfo Info(Loc);
5123 bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info);
5124 bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info);
5125
5126 if (Better1 == Better2)
5127 return nullptr;
5128
5129 return Better1 ? PS1 : PS2;
5130}
5131
5132bool Sema::isMoreSpecializedThanPrimary(
5133 ClassTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) {
5134 ClassTemplateDecl *Primary = Spec->getSpecializedTemplate();
5135 QualType PrimaryT = Primary->getInjectedClassNameSpecialization();
5136 QualType PartialT = Spec->getInjectedSpecializationType();
5137 if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info))
5138 return false;
5139 if (isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info)) {
5140 Info.clearSFINAEDiagnostic();
5141 return false;
5142 }
5143 return true;
5144}
5145
5146VarTemplatePartialSpecializationDecl *
5147Sema::getMoreSpecializedPartialSpecialization(
5148 VarTemplatePartialSpecializationDecl *PS1,
5149 VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc) {
5150 // Pretend the variable template specializations are class template
5151 // specializations and form a fake injected class name type for comparison.
5152 assert(PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() &&((PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate
() && "the partial specializations being compared should specialize"
" the same template.") ? static_cast<void> (0) : __assert_fail
("PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() && \"the partial specializations being compared should specialize\" \" the same template.\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5154, __PRETTY_FUNCTION__))
5153 "the partial specializations being compared should specialize"((PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate
() && "the partial specializations being compared should specialize"
" the same template.") ? static_cast<void> (0) : __assert_fail
("PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() && \"the partial specializations being compared should specialize\" \" the same template.\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5154, __PRETTY_FUNCTION__))
5154 " the same template.")((PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate
() && "the partial specializations being compared should specialize"
" the same template.") ? static_cast<void> (0) : __assert_fail
("PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() && \"the partial specializations being compared should specialize\" \" the same template.\""
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5154, __PRETTY_FUNCTION__))
;
5155 TemplateName Name(PS1->getSpecializedTemplate());
5156 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
5157 QualType PT1 = Context.getTemplateSpecializationType(
5158 CanonTemplate, PS1->getTemplateArgs().asArray());
5159 QualType PT2 = Context.getTemplateSpecializationType(
5160 CanonTemplate, PS2->getTemplateArgs().asArray());
5161
5162 TemplateDeductionInfo Info(Loc);
5163 bool Better1 = isAtLeastAsSpecializedAs(*this, PT1, PT2, PS2, Info);
5164 bool Better2 = isAtLeastAsSpecializedAs(*this, PT2, PT1, PS1, Info);
5165
5166 if (Better1 == Better2)
5167 return nullptr;
5168
5169 return Better1 ? PS1 : PS2;
5170}
5171
5172bool Sema::isMoreSpecializedThanPrimary(
5173 VarTemplatePartialSpecializationDecl *Spec, TemplateDeductionInfo &Info) {
5174 TemplateDecl *Primary = Spec->getSpecializedTemplate();
5175 // FIXME: Cache the injected template arguments rather than recomputing
5176 // them for each partial specialization.
5177 SmallVector<TemplateArgument, 8> PrimaryArgs;
5178 Context.getInjectedTemplateArgs(Primary->getTemplateParameters(),
5179 PrimaryArgs);
5180
5181 TemplateName CanonTemplate =
5182 Context.getCanonicalTemplateName(TemplateName(Primary));
5183 QualType PrimaryT = Context.getTemplateSpecializationType(
5184 CanonTemplate, PrimaryArgs);
5185 QualType PartialT = Context.getTemplateSpecializationType(
5186 CanonTemplate, Spec->getTemplateArgs().asArray());
5187 if (!isAtLeastAsSpecializedAs(*this, PartialT, PrimaryT, Primary, Info))
5188 return false;
5189 if (isAtLeastAsSpecializedAs(*this, PrimaryT, PartialT, Spec, Info)) {
5190 Info.clearSFINAEDiagnostic();
5191 return false;
5192 }
5193 return true;
5194}
5195
5196bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs(
5197 TemplateParameterList *P, TemplateDecl *AArg, SourceLocation Loc) {
5198 // C++1z [temp.arg.template]p4: (DR 150)
5199 // A template template-parameter P is at least as specialized as a
5200 // template template-argument A if, given the following rewrite to two
5201 // function templates...
5202
5203 // Rather than synthesize function templates, we merely perform the
5204 // equivalent partial ordering by performing deduction directly on
5205 // the template parameter lists of the template template parameters.
5206 //
5207 // Given an invented class template X with the template parameter list of
5208 // A (including default arguments):
5209 TemplateName X = Context.getCanonicalTemplateName(TemplateName(AArg));
5210 TemplateParameterList *A = AArg->getTemplateParameters();
5211
5212 // - Each function template has a single function parameter whose type is
5213 // a specialization of X with template arguments corresponding to the
5214 // template parameters from the respective function template
5215 SmallVector<TemplateArgument, 8> AArgs;
5216 Context.getInjectedTemplateArgs(A, AArgs);
5217
5218 // Check P's arguments against A's parameter list. This will fill in default
5219 // template arguments as needed. AArgs are already correct by construction.
5220 // We can't just use CheckTemplateIdType because that will expand alias
5221 // templates.
5222 SmallVector<TemplateArgument, 4> PArgs;
5223 {
5224 SFINAETrap Trap(*this);
5225
5226 Context.getInjectedTemplateArgs(P, PArgs);
5227 TemplateArgumentListInfo PArgList(P->getLAngleLoc(), P->getRAngleLoc());
5228 for (unsigned I = 0, N = P->size(); I != N; ++I) {
5229 // Unwrap packs that getInjectedTemplateArgs wrapped around pack
5230 // expansions, to form an "as written" argument list.
5231 TemplateArgument Arg = PArgs[I];
5232 if (Arg.getKind() == TemplateArgument::Pack) {
5233 assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion())((Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion
()) ? static_cast<void> (0) : __assert_fail ("Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion()"
, "/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/SemaTemplateDeduction.cpp"
, 5233, __PRETTY_FUNCTION__))
;
5234 Arg = *Arg.pack_begin();
5235 }
5236 PArgList.addArgument(getTrivialTemplateArgumentLoc(
5237 Arg, QualType(), P->getParam(I)->getLocation()));
5238 }
5239 PArgs.clear();
5240
5241 // C++1z [temp.arg.template]p3:
5242 // If the rewrite produces an invalid type, then P is not at least as
5243 // specialized as A.
5244 if (CheckTemplateArgumentList(AArg, Loc, PArgList, false, PArgs) ||
5245 Trap.hasErrorOccurred())
5246 return false;
5247 }
5248
5249 QualType AType = Context.getTemplateSpecializationType(X, AArgs);
5250 QualType PType = Context.getTemplateSpecializationType(X, PArgs);
5251
5252 // ... the function template corresponding to P is at least as specialized
5253 // as the function template corresponding to A according to the partial
5254 // ordering rules for function templates.
5255 TemplateDeductionInfo Info(Loc, A->getDepth());
5256 return isAtLeastAsSpecializedAs(*this, PType, AType, AArg, Info);
5257}
5258
5259/// Mark the template parameters that are used by the given
5260/// expression.
5261static void
5262MarkUsedTemplateParameters(ASTContext &Ctx,
5263 const Expr *E,
5264 bool OnlyDeduced,
5265 unsigned Depth,
5266 llvm::SmallBitVector &Used) {
5267 // We can deduce from a pack expansion.
5268 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E))
5269 E = Expansion->getPattern();
5270
5271 // Skip through any implicit casts we added while type-checking, and any
5272 // substitutions performed by template alias expansion.
5273 while (true) {
5274 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
5275 E = ICE->getSubExpr();
5276 else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(E))
5277 E = CE->getSubExpr();
5278 else if (const SubstNonTypeTemplateParmExpr *Subst =
5279 dyn_cast<SubstNonTypeTemplateParmExpr>(E))
5280 E = Subst->getReplacement();
5281 else
5282 break;
5283 }
5284
5285 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to
5286 // find other occurrences of template parameters.
5287 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
5288 if (!DRE)
5289 return;
5290
5291 const NonTypeTemplateParmDecl *NTTP
5292 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
5293 if (!NTTP)
5294 return;
5295
5296 if (NTTP->getDepth() == Depth)
5297 Used[NTTP->getIndex()] = true;
5298
5299 // In C++17 mode, additional arguments may be deduced from the type of a
5300 // non-type argument.
5301 if (Ctx.getLangOpts().CPlusPlus17)
5302 MarkUsedTemplateParameters(Ctx, NTTP->getType(), OnlyDeduced, Depth, Used);
5303}
5304
5305/// Mark the template parameters that are used by the given
5306/// nested name specifier.
5307static void
5308MarkUsedTemplateParameters(ASTContext &Ctx,
5309 NestedNameSpecifier *NNS,
5310 bool OnlyDeduced,
5311 unsigned Depth,
5312 llvm::SmallBitVector &Used) {
5313 if (!NNS)
5314 return;
5315
5316 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth,
5317 Used);
5318 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0),
5319 OnlyDeduced, Depth, Used);
5320}
5321
5322/// Mark the template parameters that are used by the given
5323/// template name.
5324static void
5325MarkUsedTemplateParameters(ASTContext &Ctx,
5326 TemplateName Name,
5327 bool OnlyDeduced,
5328 unsigned Depth,
5329 llvm::SmallBitVector &Used) {
5330 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
5331 if (TemplateTemplateParmDecl *TTP
5332 = dyn_cast<TemplateTemplateParmDecl>(Template)) {
5333 if (TTP->getDepth() == Depth)
5334 Used[TTP->getIndex()] = true;
5335 }
5336 return;
5337 }
5338
5339 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName())
5340 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced,
5341 Depth, Used);
5342 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName())
5343 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced,
5344 Depth, Used);
5345}
5346
5347/// Mark the template parameters that are used by the given
5348/// type.
5349static void
5350MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
5351 bool OnlyDeduced,
5352 unsigned Depth,
5353 llvm::SmallBitVector &Used) {
5354 if (T.isNull())
5355 return;
5356
5357 // Non-dependent types have nothing deducible
5358 if (!T->isDependentType())
5359 return;
5360
5361 T = Ctx.getCanonicalType(T);
5362 switch (T->getTypeClass()) {
5363 case Type::Pointer:
5364 MarkUsedTemplateParameters(Ctx,
5365 cast<PointerType>(T)->getPointeeType(),
5366 OnlyDeduced,
5367 Depth,
5368 Used);
5369 break;
5370
5371 case Type::BlockPointer:
5372 MarkUsedTemplateParameters(Ctx,
5373 cast<BlockPointerType>(T)->getPointeeType(),
5374 OnlyDeduced,
5375 Depth,
5376 Used);
5377 break;
5378
5379 case Type::LValueReference:
5380 case Type::RValueReference:
5381 MarkUsedTemplateParameters(Ctx,
5382 cast<ReferenceType>(T)->getPointeeType(),
5383 OnlyDeduced,
5384 Depth,
5385 Used);
5386 break;
5387
5388 case Type::MemberPointer: {
5389 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr());
5390 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced,
5391 Depth, Used);
5392 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0),
5393 OnlyDeduced, Depth, Used);
5394 break;
5395 }
5396
5397 case Type::DependentSizedArray:
5398 MarkUsedTemplateParameters(Ctx,
5399 cast<DependentSizedArrayType>(T)->getSizeExpr(),
5400 OnlyDeduced, Depth, Used);
5401 // Fall through to check the element type
5402 LLVM_FALLTHROUGH[[gnu::fallthrough]];
5403
5404 case Type::ConstantArray:
5405 case Type::IncompleteArray:
5406 MarkUsedTemplateParameters(Ctx,
5407 cast<ArrayType>(T)->getElementType(),
5408 OnlyDeduced, Depth, Used);
5409 break;
5410
5411 case Type::Vector:
5412 case Type::ExtVector:
5413 MarkUsedTemplateParameters(Ctx,
5414 cast<VectorType>(T)->getElementType(),
5415 OnlyDeduced, Depth, Used);
5416 break;
5417
5418 case Type::DependentVector: {
5419 const auto *VecType = cast<DependentVectorType>(T);
5420 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
5421 Depth, Used);
5422 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, Depth,
5423 Used);
5424 break;
5425 }
5426 case Type::DependentSizedExtVector: {
5427 const DependentSizedExtVectorType *VecType
5428 = cast<DependentSizedExtVectorType>(T);
5429 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
5430 Depth, Used);
5431 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced,
5432 Depth, Used);
5433 break;
5434 }
5435
5436 case Type::DependentAddressSpace: {
5437 const DependentAddressSpaceType *DependentASType =
5438 cast<DependentAddressSpaceType>(T);
5439 MarkUsedTemplateParameters(Ctx, DependentASType->getPointeeType(),
5440 OnlyDeduced, Depth, Used);
5441 MarkUsedTemplateParameters(Ctx,
5442 DependentASType->getAddrSpaceExpr(),
5443 OnlyDeduced, Depth, Used);
5444 break;
5445 }
5446
5447 case Type::FunctionProto: {
5448 const FunctionProtoType *Proto = cast<FunctionProtoType>(T);
5449 MarkUsedTemplateParameters(Ctx, Proto->getReturnType(), OnlyDeduced, Depth,
5450 Used);
5451 for (unsigned I = 0, N = Proto->getNumParams(); I != N; ++I) {
5452 // C++17 [temp.deduct.type]p5:
5453 // The non-deduced contexts are: [...]
5454 // -- A function parameter pack that does not occur at the end of the
5455 // parameter-declaration-list.
5456 if (!OnlyDeduced || I + 1 == N ||
5457 !Proto->getParamType(I)->getAs<PackExpansionType>()) {
5458 MarkUsedTemplateParameters(Ctx, Proto->getParamType(I), OnlyDeduced,
5459 Depth, Used);
5460 } else {
5461 // FIXME: C++17 [temp.deduct.call]p1:
5462 // When a function parameter pack appears in a non-deduced context,
5463 // the type of that pack is never deduced.
5464 //
5465 // We should also track a set of "never deduced" parameters, and
5466 // subtract that from the list of deduced parameters after marking.
5467 }
5468 }
5469 if (auto *E = Proto->getNoexceptExpr())
5470 MarkUsedTemplateParameters(Ctx, E, OnlyDeduced, Depth, Used);
5471 break;
5472 }
5473
5474 case Type::TemplateTypeParm: {
5475 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T);
5476 if (TTP->getDepth() == Depth)
5477 Used[TTP->getIndex()] = true;
5478 break;
5479 }
5480
5481 case Type::SubstTemplateTypeParmPack: {
5482 const SubstTemplateTypeParmPackType *Subst
5483 = cast<SubstTemplateTypeParmPackType>(T);
5484 MarkUsedTemplateParameters(Ctx,
5485 QualType(Subst->getReplacedParameter(), 0),
5486 OnlyDeduced, Depth, Used);
5487 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(),
5488 OnlyDeduced, Depth, Used);
5489 break;
5490 }
5491
5492 case Type::InjectedClassName:
5493 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
5494 LLVM_FALLTHROUGH[[gnu::fallthrough]];
5495
5496 case Type::TemplateSpecialization: {
5497 const TemplateSpecializationType *Spec
5498 = cast<TemplateSpecializationType>(T);
5499 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced,
5500 Depth, Used);
5501
5502 // C++0x [temp.deduct.type]p9:
5503 // If the template argument list of P contains a pack expansion that is
5504 // not the last template argument, the entire template argument list is a
5505 // non-deduced context.
5506 if (OnlyDeduced &&
5507 hasPackExpansionBeforeEnd(Spec->template_arguments()))
5508 break;
5509
5510 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
5511 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
5512 Used);
5513 break;
5514 }
5515
5516 case Type::Complex:
5517 if (!OnlyDeduced)
5518 MarkUsedTemplateParameters(Ctx,
5519 cast<ComplexType>(T)->getElementType(),
5520 OnlyDeduced, Depth, Used);
5521 break;
5522
5523 case Type::Atomic:
5524 if (!OnlyDeduced)
5525 MarkUsedTemplateParameters(Ctx,
5526 cast<AtomicType>(T)->getValueType(),
5527 OnlyDeduced, Depth, Used);
5528 break;
5529
5530 case Type::DependentName:
5531 if (!OnlyDeduced)
5532 MarkUsedTemplateParameters(Ctx,
5533 cast<DependentNameType>(T)->getQualifier(),
5534 OnlyDeduced, Depth, Used);
5535 break;
5536
5537 case Type::DependentTemplateSpecialization: {
5538 // C++14 [temp.deduct.type]p5:
5539 // The non-deduced contexts are:
5540 // -- The nested-name-specifier of a type that was specified using a
5541 // qualified-id
5542 //
5543 // C++14 [temp.deduct.type]p6:
5544 // When a type name is specified in a way that includes a non-deduced
5545 // context, all of the types that comprise that type name are also
5546 // non-deduced.
5547 if (OnlyDeduced)
5548 break;
5549
5550 const DependentTemplateSpecializationType *Spec
5551 = cast<DependentTemplateSpecializationType>(T);
5552
5553 MarkUsedTemplateParameters(Ctx, Spec->getQualifier(),
5554 OnlyDeduced, Depth, Used);
5555
5556 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
5557 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
5558 Used);
5559 break;
5560 }
5561
5562 case Type::TypeOf:
5563 if (!OnlyDeduced)
5564 MarkUsedTemplateParameters(Ctx,
5565 cast<TypeOfType>(T)->getUnderlyingType(),
5566 OnlyDeduced, Depth, Used);
5567 break;
5568
5569 case Type::TypeOfExpr:
5570 if (!OnlyDeduced)
5571 MarkUsedTemplateParameters(Ctx,
5572 cast<TypeOfExprType>(T)->getUnderlyingExpr(),
5573 OnlyDeduced, Depth, Used);
5574 break;
5575
5576 case Type::Decltype:
5577 if (!OnlyDeduced)
5578 MarkUsedTemplateParameters(Ctx,
5579 cast<DecltypeType>(T)->getUnderlyingExpr(),
5580 OnlyDeduced, Depth, Used);
5581 break;
5582
5583 case Type::UnaryTransform:
5584 if (!OnlyDeduced)
5585 MarkUsedTemplateParameters(Ctx,
5586 cast<UnaryTransformType>(T)->getUnderlyingType(),
5587 OnlyDeduced, Depth, Used);
5588 break;
5589
5590 case Type::PackExpansion:
5591 MarkUsedTemplateParameters(Ctx,
5592 cast<PackExpansionType>(T)->getPattern(),
5593 OnlyDeduced, Depth, Used);
5594 break;
5595
5596 case Type::Auto:
5597 case Type::DeducedTemplateSpecialization:
5598 MarkUsedTemplateParameters(Ctx,
5599 cast<DeducedType>(T)->getDeducedType(),
5600 OnlyDeduced, Depth, Used);
5601 break;
5602
5603 // None of these types have any template parameters in them.
5604 case Type::Builtin:
5605 case Type::VariableArray:
5606 case Type::FunctionNoProto:
5607 case Type::Record:
5608 case Type::Enum:
5609 case Type::ObjCInterface:
5610 case Type::ObjCObject:
5611 case Type::ObjCObjectPointer:
5612 case Type::UnresolvedUsing:
5613 case Type::Pipe:
5614#define TYPE(Class, Base)
5615#define ABSTRACT_TYPE(Class, Base)
5616#define DEPENDENT_TYPE(Class, Base)
5617#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
5618#include "clang/AST/TypeNodes.inc"
5619 break;
5620 }
5621}
5622
5623/// Mark the template parameters that are used by this
5624/// template argument.
5625static void
5626MarkUsedTemplateParameters(ASTContext &Ctx,
5627 const TemplateArgument &TemplateArg,
5628 bool OnlyDeduced,
5629 unsigned Depth,
5630 llvm::SmallBitVector &Used) {
5631 switch (TemplateArg.getKind()) {
5632 case TemplateArgument::Null:
5633 case TemplateArgument::Integral:
5634 case TemplateArgument::Declaration:
5635 break;
5636
5637 case TemplateArgument::NullPtr:
5638 MarkUsedTemplateParameters(Ctx, TemplateArg.getNullPtrType(), OnlyDeduced,
5639 Depth, Used);
5640 break;
5641
5642 case TemplateArgument::Type:
5643 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced,
5644 Depth, Used);
5645 break;
5646
5647 case TemplateArgument::Template:
5648 case TemplateArgument::TemplateExpansion:
5649 MarkUsedTemplateParameters(Ctx,
5650 TemplateArg.getAsTemplateOrTemplatePattern(),
5651 OnlyDeduced, Depth, Used);
5652 break;
5653
5654 case TemplateArgument::Expression:
5655 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced,
5656 Depth, Used);
5657 break;
5658
5659 case TemplateArgument::Pack:
5660 for (const auto &P : TemplateArg.pack_elements())
5661 MarkUsedTemplateParameters(Ctx, P, OnlyDeduced, Depth, Used);
5662 break;
5663 }
5664}
5665
5666/// Mark which template parameters can be deduced from a given
5667/// template argument list.
5668///
5669/// \param TemplateArgs the template argument list from which template
5670/// parameters will be deduced.
5671///
5672/// \param Used a bit vector whose elements will be set to \c true
5673/// to indicate when the corresponding template parameter will be
5674/// deduced.
5675void
5676Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
5677 bool OnlyDeduced, unsigned Depth,
5678 llvm::SmallBitVector &Used) {
5679 // C++0x [temp.deduct.type]p9:
5680 // If the template argument list of P contains a pack expansion that is not
5681 // the last template argument, the entire template argument list is a
5682 // non-deduced context.
5683 if (OnlyDeduced &&
5684 hasPackExpansionBeforeEnd(TemplateArgs.asArray()))
5685 return;
5686
5687 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
5688 ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced,
5689 Depth, Used);
5690}
5691
5692/// Marks all of the template parameters that will be deduced by a
5693/// call to the given function template.
5694void Sema::MarkDeducedTemplateParameters(
5695 ASTContext &Ctx, const FunctionTemplateDecl *FunctionTemplate,
5696 llvm::SmallBitVector &Deduced) {
5697 TemplateParameterList *TemplateParams
5698 = FunctionTemplate->getTemplateParameters();
5699 Deduced.clear();
5700 Deduced.resize(TemplateParams->size());
5701
5702 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
5703 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I)
5704 ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(),
5705 true, TemplateParams->getDepth(), Deduced);
5706}
5707
5708bool hasDeducibleTemplateParameters(Sema &S,
5709 FunctionTemplateDecl *FunctionTemplate,
5710 QualType T) {
5711 if (!T->isDependentType())
5712 return false;
5713
5714 TemplateParameterList *TemplateParams
5715 = FunctionTemplate->getTemplateParameters();
5716 llvm::SmallBitVector Deduced(TemplateParams->size());
5717 ::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(),
5718 Deduced);
5719
5720 return Deduced.any();
5721}

/build/llvm-toolchain-snapshot-10~svn373517/tools/clang/lib/Sema/TreeTransform.h

1//===------- TreeTransform.h - Semantic Tree Transformation -----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//===----------------------------------------------------------------------===//
7//
8// This file implements a semantic tree transformation that takes a given
9// AST and rebuilds it, possibly transforming some nodes in the process.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_LIB_SEMA_TREETRANSFORM_H
14#define LLVM_CLANG_LIB_SEMA_TREETRANSFORM_H
15
16#include "CoroutineStmtBuilder.h"
17#include "TypeLocBuilder.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/AST/DeclTemplate.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ExprCXX.h"
23#include "clang/AST/ExprObjC.h"
24#include "clang/AST/ExprOpenMP.h"
25#include "clang/AST/Stmt.h"
26#include "clang/AST/StmtCXX.h"
27#include "clang/AST/StmtObjC.h"
28#include "clang/AST/StmtOpenMP.h"
29#include "clang/Sema/Designator.h"
30#include "clang/Sema/Lookup.h"
31#include "clang/Sema/Ownership.h"
32#include "clang/Sema/ParsedTemplate.h"
33#include "clang/Sema/ScopeInfo.h"
34#include "clang/Sema/SemaDiagnostic.h"
35#include "clang/Sema/SemaInternal.h"
36#include "llvm/ADT/ArrayRef.h"
37#include "llvm/Support/ErrorHandling.h"
38#include <algorithm>
39
40namespace clang {
41using namespace sema;
42
43/// A semantic tree transformation that allows one to transform one
44/// abstract syntax tree into another.
45///
46/// A new tree transformation is defined by creating a new subclass \c X of
47/// \c TreeTransform<X> and then overriding certain operations to provide
48/// behavior specific to that transformation. For example, template
49/// instantiation is implemented as a tree transformation where the
50/// transformation of TemplateTypeParmType nodes involves substituting the
51/// template arguments for their corresponding template parameters; a similar
52/// transformation is performed for non-type template parameters and
53/// template template parameters.
54///
55/// This tree-transformation template uses static polymorphism to allow
56/// subclasses to customize any of its operations. Thus, a subclass can
57/// override any of the transformation or rebuild operators by providing an
58/// operation with the same signature as the default implementation. The
59/// overriding function should not be virtual.
60///
61/// Semantic tree transformations are split into two stages, either of which
62/// can be replaced by a subclass. The "transform" step transforms an AST node
63/// or the parts of an AST node using the various transformation functions,
64/// then passes the pieces on to the "rebuild" step, which constructs a new AST
65/// node of the appropriate kind from the pieces. The default transformation
66/// routines recursively transform the operands to composite AST nodes (e.g.,
67/// the pointee type of a PointerType node) and, if any of those operand nodes
68/// were changed by the transformation, invokes the rebuild operation to create
69/// a new AST node.
70///
71/// Subclasses can customize the transformation at various levels. The
72/// most coarse-grained transformations involve replacing TransformType(),
73/// TransformExpr(), TransformDecl(), TransformNestedNameSpecifierLoc(),
74/// TransformTemplateName(), or TransformTemplateArgument() with entirely
75/// new implementations.
76///
77/// For more fine-grained transformations, subclasses can replace any of the
78/// \c TransformXXX functions (where XXX is the name of an AST node, e.g.,
79/// PointerType, StmtExpr) to alter the transformation. As mentioned previously,
80/// replacing TransformTemplateTypeParmType() allows template instantiation
81/// to substitute template arguments for their corresponding template
82/// parameters. Additionally, subclasses can override the \c RebuildXXX
83/// functions to control how AST nodes are rebuilt when their operands change.
84/// By default, \c TreeTransform will invoke semantic analysis to rebuild
85/// AST nodes. However, certain other tree transformations (e.g, cloning) may
86/// be able to use more efficient rebuild steps.
87///
88/// There are a handful of other functions that can be overridden, allowing one
89/// to avoid traversing nodes that don't need any transformation
90/// (\c AlreadyTransformed()), force rebuilding AST nodes even when their
91/// operands have not changed (\c AlwaysRebuild()), and customize the
92/// default locations and entity names used for type-checking
93/// (\c getBaseLocation(), \c getBaseEntity()).
94template<typename Derived>
95class TreeTransform {
96 /// Private RAII object that helps us forget and then re-remember
97 /// the template argument corresponding to a partially-substituted parameter
98 /// pack.
99 class ForgetPartiallySubstitutedPackRAII {
100 Derived &Self;
101 TemplateArgument Old;
102
103 public:
104 ForgetPartiallySubstitutedPackRAII(Derived &Self) : Self(Self) {
105 Old = Self.ForgetPartiallySubstitutedPack();
106 }
107
108 ~ForgetPartiallySubstitutedPackRAII() {
109 Self.RememberPartiallySubstitutedPack(Old);
110 }
111 };
112
113protected:
114 Sema &SemaRef;
115
116 /// The set of local declarations that have been transformed, for
117 /// cases where we are forced to build new declarations within the transformer
118 /// rather than in the subclass (e.g., lambda closure types).
119 llvm::DenseMap<Decl *, Decl *> TransformedLocalDecls;
120
121public:
122 /// Initializes a new tree transformer.
123 TreeTransform(Sema &SemaRef) : SemaRef(SemaRef) { }
124
125 /// Retrieves a reference to the derived class.
126 Derived &getDerived() { return static_cast<Derived&>(*this); }
127
128 /// Retrieves a reference to the derived class.
129 const Derived &getDerived() const {
130 return static_cast<const Derived&>(*this);
131 }
132
133 static inline ExprResult Owned(Expr *E) { return E; }
134 static inline StmtResult Owned(Stmt *S) { return S; }
135
136 /// Retrieves a reference to the semantic analysis object used for
137 /// this tree transform.
138 Sema &getSema() const { return SemaRef; }
139
140 /// Whether the transformation should always rebuild AST nodes, even
141 /// if none of the children have changed.
142 ///
143 /// Subclasses may override this function to specify when the transformation
144 /// should rebuild all AST nodes.
145 ///
146 /// We must always rebuild all AST nodes when performing variadic template
147 /// pack expansion, in order to avoid violating the AST invariant that each
148 /// statement node appears at most once in its containing declaration.
149 bool AlwaysRebuild() { return SemaRef.ArgumentPackSubstitutionIndex != -1; }
150
151 /// Whether the transformation is forming an expression or statement that
152 /// replaces the original. In this case, we'll reuse mangling numbers from
153 /// existing lambdas.
154 bool ReplacingOriginal() { return false; }
155
156 /// Returns the location of the entity being transformed, if that
157 /// information was not available elsewhere in the AST.
158 ///
159 /// By default, returns no source-location information. Subclasses can
160 /// provide an alternative implementation that provides better location
161 /// information.
162 SourceLocation getBaseLocation() { return SourceLocation(); }
163
164 /// Returns the name of the entity being transformed, if that
165 /// information was not available elsewhere in the AST.
166 ///
167 /// By default, returns an empty name. Subclasses can provide an alternative
168 /// implementation with a more precise name.
169 DeclarationName getBaseEntity() { return DeclarationName(); }
170
171 /// Sets the "base" location and entity when that
172 /// information is known based on another transformation.
173 ///
174 /// By default, the source location and entity are ignored. Subclasses can
175 /// override this function to provide a customized implementation.
176 void setBase(SourceLocation Loc, DeclarationName Entity) { }
177
178 /// RAII object that temporarily sets the base location and entity
179 /// used for reporting diagnostics in types.
180 class TemporaryBase {
181 TreeTransform &Self;
182 SourceLocation OldLocation;
183 DeclarationName OldEntity;
184
185 public:
186 TemporaryBase(TreeTransform &Self, SourceLocation Location,
187 DeclarationName Entity) : Self(Self) {
188 OldLocation = Self.getDerived().getBaseLocation();
189 OldEntity = Self.getDerived().getBaseEntity();
190
191 if (Location.isValid())
192 Self.getDerived().setBase(Location, Entity);
193 }
194
195 ~TemporaryBase() {
196 Self.getDerived().setBase(OldLocation, OldEntity);
197 }
198 };
199
200 /// Determine whether the given type \p T has already been
201 /// transformed.
202 ///
203 /// Subclasses can provide an alternative implementation of this routine
204 /// to short-circuit evaluation when it is known that a given type will
205 /// not change. For example, template instantiation need not traverse
206 /// non-dependent types.
207 bool AlreadyTransformed(QualType T) {
208 return T.isNull();
209 }
210
211 /// Determine whether the given call argument should be dropped, e.g.,
212 /// because it is a default argument.
213 ///
214 /// Subclasses can provide an alternative implementation of this routine to
215 /// determine which kinds of call arguments get dropped. By default,
216 /// CXXDefaultArgument nodes are dropped (prior to transformation).
217 bool DropCallArgument(Expr *E) {
218 return E->isDefaultArgument();
219 }
220
221 /// Determine whether we should expand a pack expansion with the
222 /// given set of parameter packs into separate arguments by repeatedly
223 /// transforming the pattern.
224 ///
225 /// By default, the transformer never tries to expand pack expansions.
226 /// Subclasses can override this routine to provide different behavior.
227 ///
228 /// \param EllipsisLoc The location of the ellipsis that identifies the
229 /// pack expansion.
230 ///
231 /// \param PatternRange The source range that covers the entire pattern of
232 /// the pack expansion.
233 ///
234 /// \param Unexpanded The set of unexpanded parameter packs within the
235 /// pattern.
236 ///
237 /// \param ShouldExpand Will be set to \c true if the transformer should
238 /// expand the corresponding pack expansions into separate arguments. When
239 /// set, \c NumExpansions must also be set.
240 ///
241 /// \param RetainExpansion Whether the caller should add an unexpanded
242 /// pack expansion after all of the expanded arguments. This is used
243 /// when extending explicitly-specified template argument packs per
244 /// C++0x [temp.arg.explicit]p9.
245 ///
246 /// \param NumExpansions The number of separate arguments that will be in
247 /// the expanded form of the corresponding pack expansion. This is both an
248 /// input and an output parameter, which can be set by the caller if the
249 /// number of expansions is known a priori (e.g., due to a prior substitution)
250 /// and will be set by the callee when the number of expansions is known.
251 /// The callee must set this value when \c ShouldExpand is \c true; it may
252 /// set this value in other cases.
253 ///
254 /// \returns true if an error occurred (e.g., because the parameter packs
255 /// are to be instantiated with arguments of different lengths), false
256 /// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
257 /// must be set.
258 bool TryExpandParameterPacks(SourceLocation EllipsisLoc,
259 SourceRange PatternRange,
260 ArrayRef<UnexpandedParameterPack> Unexpanded,
261 bool &ShouldExpand,
262 bool &RetainExpansion,
263 Optional<unsigned> &NumExpansions) {
264 ShouldExpand = false;
265 return false;
266 }
267
268 /// "Forget" about the partially-substituted pack template argument,
269 /// when performing an instantiation that must preserve the parameter pack
270 /// use.
271 ///
272 /// This routine is meant to be overridden by the template instantiator.
273 TemplateArgument ForgetPartiallySubstitutedPack() {
274 return TemplateArgument();
275 }
276
277 /// "Remember" the partially-substituted pack template argument
278 /// after performing an instantiation that must preserve the parameter pack
279 /// use.
280 ///
281 /// This routine is meant to be overridden by the template instantiator.
282 void RememberPartiallySubstitutedPack(TemplateArgument Arg) { }
283
284 /// Note to the derived class when a function parameter pack is
285 /// being expanded.
286 void ExpandingFunctionParameterPack(ParmVarDecl *Pack) { }
287
288 /// Transforms the given type into another type.
289 ///
290 /// By default, this routine transforms a type by creating a
291 /// TypeSourceInfo for it and delegating to the appropriate
292 /// function. This is expensive, but we don't mind, because
293 /// this method is deprecated anyway; all users should be
294 /// switched to storing TypeSourceInfos.
295 ///
296 /// \returns the transformed type.
297 QualType TransformType(QualType T);
298