SemaTemplateDeduction.cpp revision fc55a8290a3e81111c0a373e1a04b09dd7da0b98
1//===------- SemaTemplateDeduction.cpp - Template Argument Deduction ------===/ 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7//===----------------------------------------------------------------------===/ 8// 9// This file implements C++ template argument deduction. 10// 11//===----------------------------------------------------------------------===/ 12 13#include "clang/Sema/Sema.h" 14#include "clang/Sema/DeclSpec.h" 15#include "clang/Sema/Template.h" 16#include "clang/Sema/TemplateDeduction.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/DeclObjC.h" 19#include "clang/AST/DeclTemplate.h" 20#include "clang/AST/StmtVisitor.h" 21#include "clang/AST/Expr.h" 22#include "clang/AST/ExprCXX.h" 23#include "llvm/ADT/SmallBitVector.h" 24#include "TreeTransform.h" 25#include <algorithm> 26 27namespace clang { 28 using namespace sema; 29 30 /// \brief Various flags that control template argument deduction. 31 /// 32 /// These flags can be bitwise-OR'd together. 33 enum TemplateDeductionFlags { 34 /// \brief No template argument deduction flags, which indicates the 35 /// strictest results for template argument deduction (as used for, e.g., 36 /// matching class template partial specializations). 37 TDF_None = 0, 38 /// \brief Within template argument deduction from a function call, we are 39 /// matching with a parameter type for which the original parameter was 40 /// a reference. 41 TDF_ParamWithReferenceType = 0x1, 42 /// \brief Within template argument deduction from a function call, we 43 /// are matching in a case where we ignore cv-qualifiers. 44 TDF_IgnoreQualifiers = 0x02, 45 /// \brief Within template argument deduction from a function call, 46 /// we are matching in a case where we can perform template argument 47 /// deduction from a template-id of a derived class of the argument type. 48 TDF_DerivedClass = 0x04, 49 /// \brief Allow non-dependent types to differ, e.g., when performing 50 /// template argument deduction from a function call where conversions 51 /// may apply. 52 TDF_SkipNonDependent = 0x08, 53 /// \brief Whether we are performing template argument deduction for 54 /// parameters and arguments in a top-level template argument 55 TDF_TopLevelParameterTypeList = 0x10 56 }; 57} 58 59using namespace clang; 60 61/// \brief Compare two APSInts, extending and switching the sign as 62/// necessary to compare their values regardless of underlying type. 63static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) { 64 if (Y.getBitWidth() > X.getBitWidth()) 65 X = X.extend(Y.getBitWidth()); 66 else if (Y.getBitWidth() < X.getBitWidth()) 67 Y = Y.extend(X.getBitWidth()); 68 69 // If there is a signedness mismatch, correct it. 70 if (X.isSigned() != Y.isSigned()) { 71 // If the signed value is negative, then the values cannot be the same. 72 if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative())) 73 return false; 74 75 Y.setIsSigned(true); 76 X.setIsSigned(true); 77 } 78 79 return X == Y; 80} 81 82static Sema::TemplateDeductionResult 83DeduceTemplateArguments(Sema &S, 84 TemplateParameterList *TemplateParams, 85 const TemplateArgument &Param, 86 TemplateArgument Arg, 87 TemplateDeductionInfo &Info, 88 SmallVectorImpl<DeducedTemplateArgument> &Deduced); 89 90/// \brief Whether template argument deduction for two reference parameters 91/// resulted in the argument type, parameter type, or neither type being more 92/// qualified than the other. 93enum DeductionQualifierComparison { 94 NeitherMoreQualified = 0, 95 ParamMoreQualified, 96 ArgMoreQualified 97}; 98 99/// \brief Stores the result of comparing two reference parameters while 100/// performing template argument deduction for partial ordering of function 101/// templates. 102struct RefParamPartialOrderingComparison { 103 /// \brief Whether the parameter type is an rvalue reference type. 104 bool ParamIsRvalueRef; 105 /// \brief Whether the argument type is an rvalue reference type. 106 bool ArgIsRvalueRef; 107 108 /// \brief Whether the parameter or argument (or neither) is more qualified. 109 DeductionQualifierComparison Qualifiers; 110}; 111 112 113 114static Sema::TemplateDeductionResult 115DeduceTemplateArgumentsByTypeMatch(Sema &S, 116 TemplateParameterList *TemplateParams, 117 QualType Param, 118 QualType Arg, 119 TemplateDeductionInfo &Info, 120 SmallVectorImpl<DeducedTemplateArgument> & 121 Deduced, 122 unsigned TDF, 123 bool PartialOrdering = false, 124 SmallVectorImpl<RefParamPartialOrderingComparison> * 125 RefParamComparisons = 0); 126 127static Sema::TemplateDeductionResult 128DeduceTemplateArguments(Sema &S, 129 TemplateParameterList *TemplateParams, 130 const TemplateArgument *Params, unsigned NumParams, 131 const TemplateArgument *Args, unsigned NumArgs, 132 TemplateDeductionInfo &Info, 133 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 134 bool NumberOfArgumentsMustMatch = true); 135 136/// \brief If the given expression is of a form that permits the deduction 137/// of a non-type template parameter, return the declaration of that 138/// non-type template parameter. 139static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) { 140 if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E)) 141 E = IC->getSubExpr(); 142 143 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 144 return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 145 146 return 0; 147} 148 149/// \brief Determine whether two declaration pointers refer to the same 150/// declaration. 151static bool isSameDeclaration(Decl *X, Decl *Y) { 152 if (!X || !Y) 153 return !X && !Y; 154 155 if (NamedDecl *NX = dyn_cast<NamedDecl>(X)) 156 X = NX->getUnderlyingDecl(); 157 if (NamedDecl *NY = dyn_cast<NamedDecl>(Y)) 158 Y = NY->getUnderlyingDecl(); 159 160 return X->getCanonicalDecl() == Y->getCanonicalDecl(); 161} 162 163/// \brief Verify that the given, deduced template arguments are compatible. 164/// 165/// \returns The deduced template argument, or a NULL template argument if 166/// the deduced template arguments were incompatible. 167static DeducedTemplateArgument 168checkDeducedTemplateArguments(ASTContext &Context, 169 const DeducedTemplateArgument &X, 170 const DeducedTemplateArgument &Y) { 171 // We have no deduction for one or both of the arguments; they're compatible. 172 if (X.isNull()) 173 return Y; 174 if (Y.isNull()) 175 return X; 176 177 switch (X.getKind()) { 178 case TemplateArgument::Null: 179 llvm_unreachable("Non-deduced template arguments handled above"); 180 181 case TemplateArgument::Type: 182 // If two template type arguments have the same type, they're compatible. 183 if (Y.getKind() == TemplateArgument::Type && 184 Context.hasSameType(X.getAsType(), Y.getAsType())) 185 return X; 186 187 return DeducedTemplateArgument(); 188 189 case TemplateArgument::Integral: 190 // If we deduced a constant in one case and either a dependent expression or 191 // declaration in another case, keep the integral constant. 192 // If both are integral constants with the same value, keep that value. 193 if (Y.getKind() == TemplateArgument::Expression || 194 Y.getKind() == TemplateArgument::Declaration || 195 (Y.getKind() == TemplateArgument::Integral && 196 hasSameExtendedValue(*X.getAsIntegral(), *Y.getAsIntegral()))) 197 return DeducedTemplateArgument(X, 198 X.wasDeducedFromArrayBound() && 199 Y.wasDeducedFromArrayBound()); 200 201 // All other combinations are incompatible. 202 return DeducedTemplateArgument(); 203 204 case TemplateArgument::Template: 205 if (Y.getKind() == TemplateArgument::Template && 206 Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate())) 207 return X; 208 209 // All other combinations are incompatible. 210 return DeducedTemplateArgument(); 211 212 case TemplateArgument::TemplateExpansion: 213 if (Y.getKind() == TemplateArgument::TemplateExpansion && 214 Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(), 215 Y.getAsTemplateOrTemplatePattern())) 216 return X; 217 218 // All other combinations are incompatible. 219 return DeducedTemplateArgument(); 220 221 case TemplateArgument::Expression: 222 // If we deduced a dependent expression in one case and either an integral 223 // constant or a declaration in another case, keep the integral constant 224 // or declaration. 225 if (Y.getKind() == TemplateArgument::Integral || 226 Y.getKind() == TemplateArgument::Declaration) 227 return DeducedTemplateArgument(Y, X.wasDeducedFromArrayBound() && 228 Y.wasDeducedFromArrayBound()); 229 230 if (Y.getKind() == TemplateArgument::Expression) { 231 // Compare the expressions for equality 232 llvm::FoldingSetNodeID ID1, ID2; 233 X.getAsExpr()->Profile(ID1, Context, true); 234 Y.getAsExpr()->Profile(ID2, Context, true); 235 if (ID1 == ID2) 236 return X; 237 } 238 239 // All other combinations are incompatible. 240 return DeducedTemplateArgument(); 241 242 case TemplateArgument::Declaration: 243 // If we deduced a declaration and a dependent expression, keep the 244 // declaration. 245 if (Y.getKind() == TemplateArgument::Expression) 246 return X; 247 248 // If we deduced a declaration and an integral constant, keep the 249 // integral constant. 250 if (Y.getKind() == TemplateArgument::Integral) 251 return Y; 252 253 // If we deduced two declarations, make sure they they refer to the 254 // same declaration. 255 if (Y.getKind() == TemplateArgument::Declaration && 256 isSameDeclaration(X.getAsDecl(), Y.getAsDecl())) 257 return X; 258 259 // All other combinations are incompatible. 260 return DeducedTemplateArgument(); 261 262 case TemplateArgument::Pack: 263 if (Y.getKind() != TemplateArgument::Pack || 264 X.pack_size() != Y.pack_size()) 265 return DeducedTemplateArgument(); 266 267 for (TemplateArgument::pack_iterator XA = X.pack_begin(), 268 XAEnd = X.pack_end(), 269 YA = Y.pack_begin(); 270 XA != XAEnd; ++XA, ++YA) { 271 if (checkDeducedTemplateArguments(Context, 272 DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()), 273 DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound())) 274 .isNull()) 275 return DeducedTemplateArgument(); 276 } 277 278 return X; 279 } 280 281 llvm_unreachable("Invalid TemplateArgument Kind!"); 282} 283 284/// \brief Deduce the value of the given non-type template parameter 285/// from the given constant. 286static Sema::TemplateDeductionResult 287DeduceNonTypeTemplateArgument(Sema &S, 288 NonTypeTemplateParmDecl *NTTP, 289 llvm::APSInt Value, QualType ValueType, 290 bool DeducedFromArrayBound, 291 TemplateDeductionInfo &Info, 292 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 293 assert(NTTP->getDepth() == 0 && 294 "Cannot deduce non-type template argument with depth > 0"); 295 296 DeducedTemplateArgument NewDeduced(Value, ValueType, DeducedFromArrayBound); 297 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, 298 Deduced[NTTP->getIndex()], 299 NewDeduced); 300 if (Result.isNull()) { 301 Info.Param = NTTP; 302 Info.FirstArg = Deduced[NTTP->getIndex()]; 303 Info.SecondArg = NewDeduced; 304 return Sema::TDK_Inconsistent; 305 } 306 307 Deduced[NTTP->getIndex()] = Result; 308 return Sema::TDK_Success; 309} 310 311/// \brief Deduce the value of the given non-type template parameter 312/// from the given type- or value-dependent expression. 313/// 314/// \returns true if deduction succeeded, false otherwise. 315static Sema::TemplateDeductionResult 316DeduceNonTypeTemplateArgument(Sema &S, 317 NonTypeTemplateParmDecl *NTTP, 318 Expr *Value, 319 TemplateDeductionInfo &Info, 320 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 321 assert(NTTP->getDepth() == 0 && 322 "Cannot deduce non-type template argument with depth > 0"); 323 assert((Value->isTypeDependent() || Value->isValueDependent()) && 324 "Expression template argument must be type- or value-dependent."); 325 326 DeducedTemplateArgument NewDeduced(Value); 327 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, 328 Deduced[NTTP->getIndex()], 329 NewDeduced); 330 331 if (Result.isNull()) { 332 Info.Param = NTTP; 333 Info.FirstArg = Deduced[NTTP->getIndex()]; 334 Info.SecondArg = NewDeduced; 335 return Sema::TDK_Inconsistent; 336 } 337 338 Deduced[NTTP->getIndex()] = Result; 339 return Sema::TDK_Success; 340} 341 342/// \brief Deduce the value of the given non-type template parameter 343/// from the given declaration. 344/// 345/// \returns true if deduction succeeded, false otherwise. 346static Sema::TemplateDeductionResult 347DeduceNonTypeTemplateArgument(Sema &S, 348 NonTypeTemplateParmDecl *NTTP, 349 Decl *D, 350 TemplateDeductionInfo &Info, 351 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 352 assert(NTTP->getDepth() == 0 && 353 "Cannot deduce non-type template argument with depth > 0"); 354 355 DeducedTemplateArgument NewDeduced(D? D->getCanonicalDecl() : 0); 356 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, 357 Deduced[NTTP->getIndex()], 358 NewDeduced); 359 if (Result.isNull()) { 360 Info.Param = NTTP; 361 Info.FirstArg = Deduced[NTTP->getIndex()]; 362 Info.SecondArg = NewDeduced; 363 return Sema::TDK_Inconsistent; 364 } 365 366 Deduced[NTTP->getIndex()] = Result; 367 return Sema::TDK_Success; 368} 369 370static Sema::TemplateDeductionResult 371DeduceTemplateArguments(Sema &S, 372 TemplateParameterList *TemplateParams, 373 TemplateName Param, 374 TemplateName Arg, 375 TemplateDeductionInfo &Info, 376 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 377 TemplateDecl *ParamDecl = Param.getAsTemplateDecl(); 378 if (!ParamDecl) { 379 // The parameter type is dependent and is not a template template parameter, 380 // so there is nothing that we can deduce. 381 return Sema::TDK_Success; 382 } 383 384 if (TemplateTemplateParmDecl *TempParam 385 = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) { 386 DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg)); 387 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, 388 Deduced[TempParam->getIndex()], 389 NewDeduced); 390 if (Result.isNull()) { 391 Info.Param = TempParam; 392 Info.FirstArg = Deduced[TempParam->getIndex()]; 393 Info.SecondArg = NewDeduced; 394 return Sema::TDK_Inconsistent; 395 } 396 397 Deduced[TempParam->getIndex()] = Result; 398 return Sema::TDK_Success; 399 } 400 401 // Verify that the two template names are equivalent. 402 if (S.Context.hasSameTemplateName(Param, Arg)) 403 return Sema::TDK_Success; 404 405 // Mismatch of non-dependent template parameter to argument. 406 Info.FirstArg = TemplateArgument(Param); 407 Info.SecondArg = TemplateArgument(Arg); 408 return Sema::TDK_NonDeducedMismatch; 409} 410 411/// \brief Deduce the template arguments by comparing the template parameter 412/// type (which is a template-id) with the template argument type. 413/// 414/// \param S the Sema 415/// 416/// \param TemplateParams the template parameters that we are deducing 417/// 418/// \param Param the parameter type 419/// 420/// \param Arg the argument type 421/// 422/// \param Info information about the template argument deduction itself 423/// 424/// \param Deduced the deduced template arguments 425/// 426/// \returns the result of template argument deduction so far. Note that a 427/// "success" result means that template argument deduction has not yet failed, 428/// but it may still fail, later, for other reasons. 429static Sema::TemplateDeductionResult 430DeduceTemplateArguments(Sema &S, 431 TemplateParameterList *TemplateParams, 432 const TemplateSpecializationType *Param, 433 QualType Arg, 434 TemplateDeductionInfo &Info, 435 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 436 assert(Arg.isCanonical() && "Argument type must be canonical"); 437 438 // Check whether the template argument is a dependent template-id. 439 if (const TemplateSpecializationType *SpecArg 440 = dyn_cast<TemplateSpecializationType>(Arg)) { 441 // Perform template argument deduction for the template name. 442 if (Sema::TemplateDeductionResult Result 443 = DeduceTemplateArguments(S, TemplateParams, 444 Param->getTemplateName(), 445 SpecArg->getTemplateName(), 446 Info, Deduced)) 447 return Result; 448 449 450 // Perform template argument deduction on each template 451 // argument. Ignore any missing/extra arguments, since they could be 452 // filled in by default arguments. 453 return DeduceTemplateArguments(S, TemplateParams, 454 Param->getArgs(), Param->getNumArgs(), 455 SpecArg->getArgs(), SpecArg->getNumArgs(), 456 Info, Deduced, 457 /*NumberOfArgumentsMustMatch=*/false); 458 } 459 460 // If the argument type is a class template specialization, we 461 // perform template argument deduction using its template 462 // arguments. 463 const RecordType *RecordArg = dyn_cast<RecordType>(Arg); 464 if (!RecordArg) 465 return Sema::TDK_NonDeducedMismatch; 466 467 ClassTemplateSpecializationDecl *SpecArg 468 = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl()); 469 if (!SpecArg) 470 return Sema::TDK_NonDeducedMismatch; 471 472 // Perform template argument deduction for the template name. 473 if (Sema::TemplateDeductionResult Result 474 = DeduceTemplateArguments(S, 475 TemplateParams, 476 Param->getTemplateName(), 477 TemplateName(SpecArg->getSpecializedTemplate()), 478 Info, Deduced)) 479 return Result; 480 481 // Perform template argument deduction for the template arguments. 482 return DeduceTemplateArguments(S, TemplateParams, 483 Param->getArgs(), Param->getNumArgs(), 484 SpecArg->getTemplateArgs().data(), 485 SpecArg->getTemplateArgs().size(), 486 Info, Deduced); 487} 488 489/// \brief Determines whether the given type is an opaque type that 490/// might be more qualified when instantiated. 491static bool IsPossiblyOpaquelyQualifiedType(QualType T) { 492 switch (T->getTypeClass()) { 493 case Type::TypeOfExpr: 494 case Type::TypeOf: 495 case Type::DependentName: 496 case Type::Decltype: 497 case Type::UnresolvedUsing: 498 case Type::TemplateTypeParm: 499 return true; 500 501 case Type::ConstantArray: 502 case Type::IncompleteArray: 503 case Type::VariableArray: 504 case Type::DependentSizedArray: 505 return IsPossiblyOpaquelyQualifiedType( 506 cast<ArrayType>(T)->getElementType()); 507 508 default: 509 return false; 510 } 511} 512 513/// \brief Retrieve the depth and index of a template parameter. 514static std::pair<unsigned, unsigned> 515getDepthAndIndex(NamedDecl *ND) { 516 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ND)) 517 return std::make_pair(TTP->getDepth(), TTP->getIndex()); 518 519 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(ND)) 520 return std::make_pair(NTTP->getDepth(), NTTP->getIndex()); 521 522 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(ND); 523 return std::make_pair(TTP->getDepth(), TTP->getIndex()); 524} 525 526/// \brief Retrieve the depth and index of an unexpanded parameter pack. 527static std::pair<unsigned, unsigned> 528getDepthAndIndex(UnexpandedParameterPack UPP) { 529 if (const TemplateTypeParmType *TTP 530 = UPP.first.dyn_cast<const TemplateTypeParmType *>()) 531 return std::make_pair(TTP->getDepth(), TTP->getIndex()); 532 533 return getDepthAndIndex(UPP.first.get<NamedDecl *>()); 534} 535 536/// \brief Helper function to build a TemplateParameter when we don't 537/// know its type statically. 538static TemplateParameter makeTemplateParameter(Decl *D) { 539 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D)) 540 return TemplateParameter(TTP); 541 else if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) 542 return TemplateParameter(NTTP); 543 544 return TemplateParameter(cast<TemplateTemplateParmDecl>(D)); 545} 546 547/// \brief Prepare to perform template argument deduction for all of the 548/// arguments in a set of argument packs. 549static void PrepareArgumentPackDeduction(Sema &S, 550 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 551 ArrayRef<unsigned> PackIndices, 552 SmallVectorImpl<DeducedTemplateArgument> &SavedPacks, 553 SmallVectorImpl< 554 SmallVector<DeducedTemplateArgument, 4> > &NewlyDeducedPacks) { 555 // Save the deduced template arguments for each parameter pack expanded 556 // by this pack expansion, then clear out the deduction. 557 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 558 // Save the previously-deduced argument pack, then clear it out so that we 559 // can deduce a new argument pack. 560 SavedPacks[I] = Deduced[PackIndices[I]]; 561 Deduced[PackIndices[I]] = TemplateArgument(); 562 563 // If the template arugment pack was explicitly specified, add that to 564 // the set of deduced arguments. 565 const TemplateArgument *ExplicitArgs; 566 unsigned NumExplicitArgs; 567 if (NamedDecl *PartiallySubstitutedPack 568 = S.CurrentInstantiationScope->getPartiallySubstitutedPack( 569 &ExplicitArgs, 570 &NumExplicitArgs)) { 571 if (getDepthAndIndex(PartiallySubstitutedPack).second == PackIndices[I]) 572 NewlyDeducedPacks[I].append(ExplicitArgs, 573 ExplicitArgs + NumExplicitArgs); 574 } 575 } 576} 577 578/// \brief Finish template argument deduction for a set of argument packs, 579/// producing the argument packs and checking for consistency with prior 580/// deductions. 581static Sema::TemplateDeductionResult 582FinishArgumentPackDeduction(Sema &S, 583 TemplateParameterList *TemplateParams, 584 bool HasAnyArguments, 585 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 586 ArrayRef<unsigned> PackIndices, 587 SmallVectorImpl<DeducedTemplateArgument> &SavedPacks, 588 SmallVectorImpl< 589 SmallVector<DeducedTemplateArgument, 4> > &NewlyDeducedPacks, 590 TemplateDeductionInfo &Info) { 591 // Build argument packs for each of the parameter packs expanded by this 592 // pack expansion. 593 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 594 if (HasAnyArguments && NewlyDeducedPacks[I].empty()) { 595 // We were not able to deduce anything for this parameter pack, 596 // so just restore the saved argument pack. 597 Deduced[PackIndices[I]] = SavedPacks[I]; 598 continue; 599 } 600 601 DeducedTemplateArgument NewPack; 602 603 if (NewlyDeducedPacks[I].empty()) { 604 // If we deduced an empty argument pack, create it now. 605 NewPack = DeducedTemplateArgument(TemplateArgument(0, 0)); 606 } else { 607 TemplateArgument *ArgumentPack 608 = new (S.Context) TemplateArgument [NewlyDeducedPacks[I].size()]; 609 std::copy(NewlyDeducedPacks[I].begin(), NewlyDeducedPacks[I].end(), 610 ArgumentPack); 611 NewPack 612 = DeducedTemplateArgument(TemplateArgument(ArgumentPack, 613 NewlyDeducedPacks[I].size()), 614 NewlyDeducedPacks[I][0].wasDeducedFromArrayBound()); 615 } 616 617 DeducedTemplateArgument Result 618 = checkDeducedTemplateArguments(S.Context, SavedPacks[I], NewPack); 619 if (Result.isNull()) { 620 Info.Param 621 = makeTemplateParameter(TemplateParams->getParam(PackIndices[I])); 622 Info.FirstArg = SavedPacks[I]; 623 Info.SecondArg = NewPack; 624 return Sema::TDK_Inconsistent; 625 } 626 627 Deduced[PackIndices[I]] = Result; 628 } 629 630 return Sema::TDK_Success; 631} 632 633/// \brief Deduce the template arguments by comparing the list of parameter 634/// types to the list of argument types, as in the parameter-type-lists of 635/// function types (C++ [temp.deduct.type]p10). 636/// 637/// \param S The semantic analysis object within which we are deducing 638/// 639/// \param TemplateParams The template parameters that we are deducing 640/// 641/// \param Params The list of parameter types 642/// 643/// \param NumParams The number of types in \c Params 644/// 645/// \param Args The list of argument types 646/// 647/// \param NumArgs The number of types in \c Args 648/// 649/// \param Info information about the template argument deduction itself 650/// 651/// \param Deduced the deduced template arguments 652/// 653/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe 654/// how template argument deduction is performed. 655/// 656/// \param PartialOrdering If true, we are performing template argument 657/// deduction for during partial ordering for a call 658/// (C++0x [temp.deduct.partial]). 659/// 660/// \param RefParamComparisons If we're performing template argument deduction 661/// in the context of partial ordering, the set of qualifier comparisons. 662/// 663/// \returns the result of template argument deduction so far. Note that a 664/// "success" result means that template argument deduction has not yet failed, 665/// but it may still fail, later, for other reasons. 666static Sema::TemplateDeductionResult 667DeduceTemplateArguments(Sema &S, 668 TemplateParameterList *TemplateParams, 669 const QualType *Params, unsigned NumParams, 670 const QualType *Args, unsigned NumArgs, 671 TemplateDeductionInfo &Info, 672 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 673 unsigned TDF, 674 bool PartialOrdering = false, 675 SmallVectorImpl<RefParamPartialOrderingComparison> * 676 RefParamComparisons = 0) { 677 // Fast-path check to see if we have too many/too few arguments. 678 if (NumParams != NumArgs && 679 !(NumParams && isa<PackExpansionType>(Params[NumParams - 1])) && 680 !(NumArgs && isa<PackExpansionType>(Args[NumArgs - 1]))) 681 return Sema::TDK_NonDeducedMismatch; 682 683 // C++0x [temp.deduct.type]p10: 684 // Similarly, if P has a form that contains (T), then each parameter type 685 // Pi of the respective parameter-type- list of P is compared with the 686 // corresponding parameter type Ai of the corresponding parameter-type-list 687 // of A. [...] 688 unsigned ArgIdx = 0, ParamIdx = 0; 689 for (; ParamIdx != NumParams; ++ParamIdx) { 690 // Check argument types. 691 const PackExpansionType *Expansion 692 = dyn_cast<PackExpansionType>(Params[ParamIdx]); 693 if (!Expansion) { 694 // Simple case: compare the parameter and argument types at this point. 695 696 // Make sure we have an argument. 697 if (ArgIdx >= NumArgs) 698 return Sema::TDK_NonDeducedMismatch; 699 700 if (isa<PackExpansionType>(Args[ArgIdx])) { 701 // C++0x [temp.deduct.type]p22: 702 // If the original function parameter associated with A is a function 703 // parameter pack and the function parameter associated with P is not 704 // a function parameter pack, then template argument deduction fails. 705 return Sema::TDK_NonDeducedMismatch; 706 } 707 708 if (Sema::TemplateDeductionResult Result 709 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 710 Params[ParamIdx], Args[ArgIdx], 711 Info, Deduced, TDF, 712 PartialOrdering, 713 RefParamComparisons)) 714 return Result; 715 716 ++ArgIdx; 717 continue; 718 } 719 720 // C++0x [temp.deduct.type]p5: 721 // The non-deduced contexts are: 722 // - A function parameter pack that does not occur at the end of the 723 // parameter-declaration-clause. 724 if (ParamIdx + 1 < NumParams) 725 return Sema::TDK_Success; 726 727 // C++0x [temp.deduct.type]p10: 728 // If the parameter-declaration corresponding to Pi is a function 729 // parameter pack, then the type of its declarator- id is compared with 730 // each remaining parameter type in the parameter-type-list of A. Each 731 // comparison deduces template arguments for subsequent positions in the 732 // template parameter packs expanded by the function parameter pack. 733 734 // Compute the set of template parameter indices that correspond to 735 // parameter packs expanded by the pack expansion. 736 SmallVector<unsigned, 2> PackIndices; 737 QualType Pattern = Expansion->getPattern(); 738 { 739 llvm::SmallBitVector SawIndices(TemplateParams->size()); 740 SmallVector<UnexpandedParameterPack, 2> Unexpanded; 741 S.collectUnexpandedParameterPacks(Pattern, Unexpanded); 742 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { 743 unsigned Depth, Index; 744 llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); 745 if (Depth == 0 && !SawIndices[Index]) { 746 SawIndices[Index] = true; 747 PackIndices.push_back(Index); 748 } 749 } 750 } 751 assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); 752 753 // Keep track of the deduced template arguments for each parameter pack 754 // expanded by this pack expansion (the outer index) and for each 755 // template argument (the inner SmallVectors). 756 SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2> 757 NewlyDeducedPacks(PackIndices.size()); 758 SmallVector<DeducedTemplateArgument, 2> 759 SavedPacks(PackIndices.size()); 760 PrepareArgumentPackDeduction(S, Deduced, PackIndices, SavedPacks, 761 NewlyDeducedPacks); 762 763 bool HasAnyArguments = false; 764 for (; ArgIdx < NumArgs; ++ArgIdx) { 765 HasAnyArguments = true; 766 767 // Deduce template arguments from the pattern. 768 if (Sema::TemplateDeductionResult Result 769 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern, 770 Args[ArgIdx], Info, Deduced, 771 TDF, PartialOrdering, 772 RefParamComparisons)) 773 return Result; 774 775 // Capture the deduced template arguments for each parameter pack expanded 776 // by this pack expansion, add them to the list of arguments we've deduced 777 // for that pack, then clear out the deduced argument. 778 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 779 DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; 780 if (!DeducedArg.isNull()) { 781 NewlyDeducedPacks[I].push_back(DeducedArg); 782 DeducedArg = DeducedTemplateArgument(); 783 } 784 } 785 } 786 787 // Build argument packs for each of the parameter packs expanded by this 788 // pack expansion. 789 if (Sema::TemplateDeductionResult Result 790 = FinishArgumentPackDeduction(S, TemplateParams, HasAnyArguments, 791 Deduced, PackIndices, SavedPacks, 792 NewlyDeducedPacks, Info)) 793 return Result; 794 } 795 796 // Make sure we don't have any extra arguments. 797 if (ArgIdx < NumArgs) 798 return Sema::TDK_NonDeducedMismatch; 799 800 return Sema::TDK_Success; 801} 802 803/// \brief Determine whether the parameter has qualifiers that are either 804/// inconsistent with or a superset of the argument's qualifiers. 805static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType, 806 QualType ArgType) { 807 Qualifiers ParamQs = ParamType.getQualifiers(); 808 Qualifiers ArgQs = ArgType.getQualifiers(); 809 810 if (ParamQs == ArgQs) 811 return false; 812 813 // Mismatched (but not missing) Objective-C GC attributes. 814 if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() && 815 ParamQs.hasObjCGCAttr()) 816 return true; 817 818 // Mismatched (but not missing) address spaces. 819 if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() && 820 ParamQs.hasAddressSpace()) 821 return true; 822 823 // Mismatched (but not missing) Objective-C lifetime qualifiers. 824 if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() && 825 ParamQs.hasObjCLifetime()) 826 return true; 827 828 // CVR qualifier superset. 829 return (ParamQs.getCVRQualifiers() != ArgQs.getCVRQualifiers()) && 830 ((ParamQs.getCVRQualifiers() | ArgQs.getCVRQualifiers()) 831 == ParamQs.getCVRQualifiers()); 832} 833 834/// \brief Deduce the template arguments by comparing the parameter type and 835/// the argument type (C++ [temp.deduct.type]). 836/// 837/// \param S the semantic analysis object within which we are deducing 838/// 839/// \param TemplateParams the template parameters that we are deducing 840/// 841/// \param ParamIn the parameter type 842/// 843/// \param ArgIn the argument type 844/// 845/// \param Info information about the template argument deduction itself 846/// 847/// \param Deduced the deduced template arguments 848/// 849/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe 850/// how template argument deduction is performed. 851/// 852/// \param PartialOrdering Whether we're performing template argument deduction 853/// in the context of partial ordering (C++0x [temp.deduct.partial]). 854/// 855/// \param RefParamComparisons If we're performing template argument deduction 856/// in the context of partial ordering, the set of qualifier comparisons. 857/// 858/// \returns the result of template argument deduction so far. Note that a 859/// "success" result means that template argument deduction has not yet failed, 860/// but it may still fail, later, for other reasons. 861static Sema::TemplateDeductionResult 862DeduceTemplateArgumentsByTypeMatch(Sema &S, 863 TemplateParameterList *TemplateParams, 864 QualType ParamIn, QualType ArgIn, 865 TemplateDeductionInfo &Info, 866 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 867 unsigned TDF, 868 bool PartialOrdering, 869 SmallVectorImpl<RefParamPartialOrderingComparison> * 870 RefParamComparisons) { 871 // We only want to look at the canonical types, since typedefs and 872 // sugar are not part of template argument deduction. 873 QualType Param = S.Context.getCanonicalType(ParamIn); 874 QualType Arg = S.Context.getCanonicalType(ArgIn); 875 876 // If the argument type is a pack expansion, look at its pattern. 877 // This isn't explicitly called out 878 if (const PackExpansionType *ArgExpansion 879 = dyn_cast<PackExpansionType>(Arg)) 880 Arg = ArgExpansion->getPattern(); 881 882 if (PartialOrdering) { 883 // C++0x [temp.deduct.partial]p5: 884 // Before the partial ordering is done, certain transformations are 885 // performed on the types used for partial ordering: 886 // - If P is a reference type, P is replaced by the type referred to. 887 const ReferenceType *ParamRef = Param->getAs<ReferenceType>(); 888 if (ParamRef) 889 Param = ParamRef->getPointeeType(); 890 891 // - If A is a reference type, A is replaced by the type referred to. 892 const ReferenceType *ArgRef = Arg->getAs<ReferenceType>(); 893 if (ArgRef) 894 Arg = ArgRef->getPointeeType(); 895 896 if (RefParamComparisons && ParamRef && ArgRef) { 897 // C++0x [temp.deduct.partial]p6: 898 // If both P and A were reference types (before being replaced with the 899 // type referred to above), determine which of the two types (if any) is 900 // more cv-qualified than the other; otherwise the types are considered 901 // to be equally cv-qualified for partial ordering purposes. The result 902 // of this determination will be used below. 903 // 904 // We save this information for later, using it only when deduction 905 // succeeds in both directions. 906 RefParamPartialOrderingComparison Comparison; 907 Comparison.ParamIsRvalueRef = ParamRef->getAs<RValueReferenceType>(); 908 Comparison.ArgIsRvalueRef = ArgRef->getAs<RValueReferenceType>(); 909 Comparison.Qualifiers = NeitherMoreQualified; 910 911 Qualifiers ParamQuals = Param.getQualifiers(); 912 Qualifiers ArgQuals = Arg.getQualifiers(); 913 if (ParamQuals.isStrictSupersetOf(ArgQuals)) 914 Comparison.Qualifiers = ParamMoreQualified; 915 else if (ArgQuals.isStrictSupersetOf(ParamQuals)) 916 Comparison.Qualifiers = ArgMoreQualified; 917 RefParamComparisons->push_back(Comparison); 918 } 919 920 // C++0x [temp.deduct.partial]p7: 921 // Remove any top-level cv-qualifiers: 922 // - If P is a cv-qualified type, P is replaced by the cv-unqualified 923 // version of P. 924 Param = Param.getUnqualifiedType(); 925 // - If A is a cv-qualified type, A is replaced by the cv-unqualified 926 // version of A. 927 Arg = Arg.getUnqualifiedType(); 928 } else { 929 // C++0x [temp.deduct.call]p4 bullet 1: 930 // - If the original P is a reference type, the deduced A (i.e., the type 931 // referred to by the reference) can be more cv-qualified than the 932 // transformed A. 933 if (TDF & TDF_ParamWithReferenceType) { 934 Qualifiers Quals; 935 QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals); 936 Quals.setCVRQualifiers(Quals.getCVRQualifiers() & 937 Arg.getCVRQualifiers()); 938 Param = S.Context.getQualifiedType(UnqualParam, Quals); 939 } 940 941 if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) { 942 // C++0x [temp.deduct.type]p10: 943 // If P and A are function types that originated from deduction when 944 // taking the address of a function template (14.8.2.2) or when deducing 945 // template arguments from a function declaration (14.8.2.6) and Pi and 946 // Ai are parameters of the top-level parameter-type-list of P and A, 947 // respectively, Pi is adjusted if it is an rvalue reference to a 948 // cv-unqualified template parameter and Ai is an lvalue reference, in 949 // which case the type of Pi is changed to be the template parameter 950 // type (i.e., T&& is changed to simply T). [ Note: As a result, when 951 // Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be 952 // deduced as X&. - end note ] 953 TDF &= ~TDF_TopLevelParameterTypeList; 954 955 if (const RValueReferenceType *ParamRef 956 = Param->getAs<RValueReferenceType>()) { 957 if (isa<TemplateTypeParmType>(ParamRef->getPointeeType()) && 958 !ParamRef->getPointeeType().getQualifiers()) 959 if (Arg->isLValueReferenceType()) 960 Param = ParamRef->getPointeeType(); 961 } 962 } 963 } 964 965 // C++ [temp.deduct.type]p9: 966 // A template type argument T, a template template argument TT or a 967 // template non-type argument i can be deduced if P and A have one of 968 // the following forms: 969 // 970 // T 971 // cv-list T 972 if (const TemplateTypeParmType *TemplateTypeParm 973 = Param->getAs<TemplateTypeParmType>()) { 974 // Just skip any attempts to deduce from a placeholder type. 975 if (Arg->isPlaceholderType()) 976 return Sema::TDK_Success; 977 978 unsigned Index = TemplateTypeParm->getIndex(); 979 bool RecanonicalizeArg = false; 980 981 // If the argument type is an array type, move the qualifiers up to the 982 // top level, so they can be matched with the qualifiers on the parameter. 983 if (isa<ArrayType>(Arg)) { 984 Qualifiers Quals; 985 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals); 986 if (Quals) { 987 Arg = S.Context.getQualifiedType(Arg, Quals); 988 RecanonicalizeArg = true; 989 } 990 } 991 992 // The argument type can not be less qualified than the parameter 993 // type. 994 if (!(TDF & TDF_IgnoreQualifiers) && 995 hasInconsistentOrSupersetQualifiersOf(Param, Arg)) { 996 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 997 Info.FirstArg = TemplateArgument(Param); 998 Info.SecondArg = TemplateArgument(Arg); 999 return Sema::TDK_Underqualified; 1000 } 1001 1002 assert(TemplateTypeParm->getDepth() == 0 && "Can't deduce with depth > 0"); 1003 assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function"); 1004 QualType DeducedType = Arg; 1005 1006 // Remove any qualifiers on the parameter from the deduced type. 1007 // We checked the qualifiers for consistency above. 1008 Qualifiers DeducedQs = DeducedType.getQualifiers(); 1009 Qualifiers ParamQs = Param.getQualifiers(); 1010 DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers()); 1011 if (ParamQs.hasObjCGCAttr()) 1012 DeducedQs.removeObjCGCAttr(); 1013 if (ParamQs.hasAddressSpace()) 1014 DeducedQs.removeAddressSpace(); 1015 if (ParamQs.hasObjCLifetime()) 1016 DeducedQs.removeObjCLifetime(); 1017 1018 // Objective-C ARC: 1019 // If template deduction would produce a lifetime qualifier on a type 1020 // that is not a lifetime type, template argument deduction fails. 1021 if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() && 1022 !DeducedType->isDependentType()) { 1023 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 1024 Info.FirstArg = TemplateArgument(Param); 1025 Info.SecondArg = TemplateArgument(Arg); 1026 return Sema::TDK_Underqualified; 1027 } 1028 1029 // Objective-C ARC: 1030 // If template deduction would produce an argument type with lifetime type 1031 // but no lifetime qualifier, the __strong lifetime qualifier is inferred. 1032 if (S.getLangOptions().ObjCAutoRefCount && 1033 DeducedType->isObjCLifetimeType() && 1034 !DeducedQs.hasObjCLifetime()) 1035 DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong); 1036 1037 DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(), 1038 DeducedQs); 1039 1040 if (RecanonicalizeArg) 1041 DeducedType = S.Context.getCanonicalType(DeducedType); 1042 1043 DeducedTemplateArgument NewDeduced(DeducedType); 1044 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context, 1045 Deduced[Index], 1046 NewDeduced); 1047 if (Result.isNull()) { 1048 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 1049 Info.FirstArg = Deduced[Index]; 1050 Info.SecondArg = NewDeduced; 1051 return Sema::TDK_Inconsistent; 1052 } 1053 1054 Deduced[Index] = Result; 1055 return Sema::TDK_Success; 1056 } 1057 1058 // Set up the template argument deduction information for a failure. 1059 Info.FirstArg = TemplateArgument(ParamIn); 1060 Info.SecondArg = TemplateArgument(ArgIn); 1061 1062 // If the parameter is an already-substituted template parameter 1063 // pack, do nothing: we don't know which of its arguments to look 1064 // at, so we have to wait until all of the parameter packs in this 1065 // expansion have arguments. 1066 if (isa<SubstTemplateTypeParmPackType>(Param)) 1067 return Sema::TDK_Success; 1068 1069 // Check the cv-qualifiers on the parameter and argument types. 1070 if (!(TDF & TDF_IgnoreQualifiers)) { 1071 if (TDF & TDF_ParamWithReferenceType) { 1072 if (hasInconsistentOrSupersetQualifiersOf(Param, Arg)) 1073 return Sema::TDK_NonDeducedMismatch; 1074 } else if (!IsPossiblyOpaquelyQualifiedType(Param)) { 1075 if (Param.getCVRQualifiers() != Arg.getCVRQualifiers()) 1076 return Sema::TDK_NonDeducedMismatch; 1077 } 1078 1079 // If the parameter type is not dependent, there is nothing to deduce. 1080 if (!Param->isDependentType()) { 1081 if (!(TDF & TDF_SkipNonDependent) && Param != Arg) 1082 return Sema::TDK_NonDeducedMismatch; 1083 1084 return Sema::TDK_Success; 1085 } 1086 } else if (!Param->isDependentType() && 1087 Param.getUnqualifiedType() == Arg.getUnqualifiedType()) { 1088 return Sema::TDK_Success; 1089 } 1090 1091 switch (Param->getTypeClass()) { 1092 // Non-canonical types cannot appear here. 1093#define NON_CANONICAL_TYPE(Class, Base) \ 1094 case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class); 1095#define TYPE(Class, Base) 1096#include "clang/AST/TypeNodes.def" 1097 1098 case Type::TemplateTypeParm: 1099 case Type::SubstTemplateTypeParmPack: 1100 llvm_unreachable("Type nodes handled above"); 1101 1102 // These types cannot be dependent, so simply check whether the types are 1103 // the same. 1104 case Type::Builtin: 1105 case Type::VariableArray: 1106 case Type::Vector: 1107 case Type::FunctionNoProto: 1108 case Type::Record: 1109 case Type::Enum: 1110 case Type::ObjCObject: 1111 case Type::ObjCInterface: 1112 case Type::ObjCObjectPointer: { 1113 if (TDF & TDF_SkipNonDependent) 1114 return Sema::TDK_Success; 1115 1116 if (TDF & TDF_IgnoreQualifiers) { 1117 Param = Param.getUnqualifiedType(); 1118 Arg = Arg.getUnqualifiedType(); 1119 } 1120 1121 return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch; 1122 } 1123 1124 // _Complex T [placeholder extension] 1125 case Type::Complex: 1126 if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>()) 1127 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1128 cast<ComplexType>(Param)->getElementType(), 1129 ComplexArg->getElementType(), 1130 Info, Deduced, TDF); 1131 1132 return Sema::TDK_NonDeducedMismatch; 1133 1134 // _Atomic T [extension] 1135 case Type::Atomic: 1136 if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>()) 1137 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1138 cast<AtomicType>(Param)->getValueType(), 1139 AtomicArg->getValueType(), 1140 Info, Deduced, TDF); 1141 1142 return Sema::TDK_NonDeducedMismatch; 1143 1144 // T * 1145 case Type::Pointer: { 1146 QualType PointeeType; 1147 if (const PointerType *PointerArg = Arg->getAs<PointerType>()) { 1148 PointeeType = PointerArg->getPointeeType(); 1149 } else if (const ObjCObjectPointerType *PointerArg 1150 = Arg->getAs<ObjCObjectPointerType>()) { 1151 PointeeType = PointerArg->getPointeeType(); 1152 } else { 1153 return Sema::TDK_NonDeducedMismatch; 1154 } 1155 1156 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass); 1157 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1158 cast<PointerType>(Param)->getPointeeType(), 1159 PointeeType, 1160 Info, Deduced, SubTDF); 1161 } 1162 1163 // T & 1164 case Type::LValueReference: { 1165 const LValueReferenceType *ReferenceArg = Arg->getAs<LValueReferenceType>(); 1166 if (!ReferenceArg) 1167 return Sema::TDK_NonDeducedMismatch; 1168 1169 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1170 cast<LValueReferenceType>(Param)->getPointeeType(), 1171 ReferenceArg->getPointeeType(), Info, Deduced, 0); 1172 } 1173 1174 // T && [C++0x] 1175 case Type::RValueReference: { 1176 const RValueReferenceType *ReferenceArg = Arg->getAs<RValueReferenceType>(); 1177 if (!ReferenceArg) 1178 return Sema::TDK_NonDeducedMismatch; 1179 1180 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1181 cast<RValueReferenceType>(Param)->getPointeeType(), 1182 ReferenceArg->getPointeeType(), 1183 Info, Deduced, 0); 1184 } 1185 1186 // T [] (implied, but not stated explicitly) 1187 case Type::IncompleteArray: { 1188 const IncompleteArrayType *IncompleteArrayArg = 1189 S.Context.getAsIncompleteArrayType(Arg); 1190 if (!IncompleteArrayArg) 1191 return Sema::TDK_NonDeducedMismatch; 1192 1193 unsigned SubTDF = TDF & TDF_IgnoreQualifiers; 1194 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1195 S.Context.getAsIncompleteArrayType(Param)->getElementType(), 1196 IncompleteArrayArg->getElementType(), 1197 Info, Deduced, SubTDF); 1198 } 1199 1200 // T [integer-constant] 1201 case Type::ConstantArray: { 1202 const ConstantArrayType *ConstantArrayArg = 1203 S.Context.getAsConstantArrayType(Arg); 1204 if (!ConstantArrayArg) 1205 return Sema::TDK_NonDeducedMismatch; 1206 1207 const ConstantArrayType *ConstantArrayParm = 1208 S.Context.getAsConstantArrayType(Param); 1209 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize()) 1210 return Sema::TDK_NonDeducedMismatch; 1211 1212 unsigned SubTDF = TDF & TDF_IgnoreQualifiers; 1213 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1214 ConstantArrayParm->getElementType(), 1215 ConstantArrayArg->getElementType(), 1216 Info, Deduced, SubTDF); 1217 } 1218 1219 // type [i] 1220 case Type::DependentSizedArray: { 1221 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg); 1222 if (!ArrayArg) 1223 return Sema::TDK_NonDeducedMismatch; 1224 1225 unsigned SubTDF = TDF & TDF_IgnoreQualifiers; 1226 1227 // Check the element type of the arrays 1228 const DependentSizedArrayType *DependentArrayParm 1229 = S.Context.getAsDependentSizedArrayType(Param); 1230 if (Sema::TemplateDeductionResult Result 1231 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1232 DependentArrayParm->getElementType(), 1233 ArrayArg->getElementType(), 1234 Info, Deduced, SubTDF)) 1235 return Result; 1236 1237 // Determine the array bound is something we can deduce. 1238 NonTypeTemplateParmDecl *NTTP 1239 = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr()); 1240 if (!NTTP) 1241 return Sema::TDK_Success; 1242 1243 // We can perform template argument deduction for the given non-type 1244 // template parameter. 1245 assert(NTTP->getDepth() == 0 && 1246 "Cannot deduce non-type template argument at depth > 0"); 1247 if (const ConstantArrayType *ConstantArrayArg 1248 = dyn_cast<ConstantArrayType>(ArrayArg)) { 1249 llvm::APSInt Size(ConstantArrayArg->getSize()); 1250 return DeduceNonTypeTemplateArgument(S, NTTP, Size, 1251 S.Context.getSizeType(), 1252 /*ArrayBound=*/true, 1253 Info, Deduced); 1254 } 1255 if (const DependentSizedArrayType *DependentArrayArg 1256 = dyn_cast<DependentSizedArrayType>(ArrayArg)) 1257 if (DependentArrayArg->getSizeExpr()) 1258 return DeduceNonTypeTemplateArgument(S, NTTP, 1259 DependentArrayArg->getSizeExpr(), 1260 Info, Deduced); 1261 1262 // Incomplete type does not match a dependently-sized array type 1263 return Sema::TDK_NonDeducedMismatch; 1264 } 1265 1266 // type(*)(T) 1267 // T(*)() 1268 // T(*)(T) 1269 case Type::FunctionProto: { 1270 unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList; 1271 const FunctionProtoType *FunctionProtoArg = 1272 dyn_cast<FunctionProtoType>(Arg); 1273 if (!FunctionProtoArg) 1274 return Sema::TDK_NonDeducedMismatch; 1275 1276 const FunctionProtoType *FunctionProtoParam = 1277 cast<FunctionProtoType>(Param); 1278 1279 if (FunctionProtoParam->getTypeQuals() 1280 != FunctionProtoArg->getTypeQuals() || 1281 FunctionProtoParam->getRefQualifier() 1282 != FunctionProtoArg->getRefQualifier() || 1283 FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic()) 1284 return Sema::TDK_NonDeducedMismatch; 1285 1286 // Check return types. 1287 if (Sema::TemplateDeductionResult Result 1288 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1289 FunctionProtoParam->getResultType(), 1290 FunctionProtoArg->getResultType(), 1291 Info, Deduced, 0)) 1292 return Result; 1293 1294 return DeduceTemplateArguments(S, TemplateParams, 1295 FunctionProtoParam->arg_type_begin(), 1296 FunctionProtoParam->getNumArgs(), 1297 FunctionProtoArg->arg_type_begin(), 1298 FunctionProtoArg->getNumArgs(), 1299 Info, Deduced, SubTDF); 1300 } 1301 1302 case Type::InjectedClassName: { 1303 // Treat a template's injected-class-name as if the template 1304 // specialization type had been used. 1305 Param = cast<InjectedClassNameType>(Param) 1306 ->getInjectedSpecializationType(); 1307 assert(isa<TemplateSpecializationType>(Param) && 1308 "injected class name is not a template specialization type"); 1309 // fall through 1310 } 1311 1312 // template-name<T> (where template-name refers to a class template) 1313 // template-name<i> 1314 // TT<T> 1315 // TT<i> 1316 // TT<> 1317 case Type::TemplateSpecialization: { 1318 const TemplateSpecializationType *SpecParam 1319 = cast<TemplateSpecializationType>(Param); 1320 1321 // Try to deduce template arguments from the template-id. 1322 Sema::TemplateDeductionResult Result 1323 = DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, 1324 Info, Deduced); 1325 1326 if (Result && (TDF & TDF_DerivedClass)) { 1327 // C++ [temp.deduct.call]p3b3: 1328 // If P is a class, and P has the form template-id, then A can be a 1329 // derived class of the deduced A. Likewise, if P is a pointer to a 1330 // class of the form template-id, A can be a pointer to a derived 1331 // class pointed to by the deduced A. 1332 // 1333 // More importantly: 1334 // These alternatives are considered only if type deduction would 1335 // otherwise fail. 1336 if (const RecordType *RecordT = Arg->getAs<RecordType>()) { 1337 // We cannot inspect base classes as part of deduction when the type 1338 // is incomplete, so either instantiate any templates necessary to 1339 // complete the type, or skip over it if it cannot be completed. 1340 if (S.RequireCompleteType(Info.getLocation(), Arg, 0)) 1341 return Result; 1342 1343 // Use data recursion to crawl through the list of base classes. 1344 // Visited contains the set of nodes we have already visited, while 1345 // ToVisit is our stack of records that we still need to visit. 1346 llvm::SmallPtrSet<const RecordType *, 8> Visited; 1347 SmallVector<const RecordType *, 8> ToVisit; 1348 ToVisit.push_back(RecordT); 1349 bool Successful = false; 1350 SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(), 1351 Deduced.end()); 1352 while (!ToVisit.empty()) { 1353 // Retrieve the next class in the inheritance hierarchy. 1354 const RecordType *NextT = ToVisit.back(); 1355 ToVisit.pop_back(); 1356 1357 // If we have already seen this type, skip it. 1358 if (!Visited.insert(NextT)) 1359 continue; 1360 1361 // If this is a base class, try to perform template argument 1362 // deduction from it. 1363 if (NextT != RecordT) { 1364 Sema::TemplateDeductionResult BaseResult 1365 = DeduceTemplateArguments(S, TemplateParams, SpecParam, 1366 QualType(NextT, 0), Info, Deduced); 1367 1368 // If template argument deduction for this base was successful, 1369 // note that we had some success. Otherwise, ignore any deductions 1370 // from this base class. 1371 if (BaseResult == Sema::TDK_Success) { 1372 Successful = true; 1373 DeducedOrig.clear(); 1374 DeducedOrig.append(Deduced.begin(), Deduced.end()); 1375 } 1376 else 1377 Deduced = DeducedOrig; 1378 } 1379 1380 // Visit base classes 1381 CXXRecordDecl *Next = cast<CXXRecordDecl>(NextT->getDecl()); 1382 for (CXXRecordDecl::base_class_iterator Base = Next->bases_begin(), 1383 BaseEnd = Next->bases_end(); 1384 Base != BaseEnd; ++Base) { 1385 assert(Base->getType()->isRecordType() && 1386 "Base class that isn't a record?"); 1387 ToVisit.push_back(Base->getType()->getAs<RecordType>()); 1388 } 1389 } 1390 1391 if (Successful) 1392 return Sema::TDK_Success; 1393 } 1394 1395 } 1396 1397 return Result; 1398 } 1399 1400 // T type::* 1401 // T T::* 1402 // T (type::*)() 1403 // type (T::*)() 1404 // type (type::*)(T) 1405 // type (T::*)(T) 1406 // T (type::*)(T) 1407 // T (T::*)() 1408 // T (T::*)(T) 1409 case Type::MemberPointer: { 1410 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param); 1411 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg); 1412 if (!MemPtrArg) 1413 return Sema::TDK_NonDeducedMismatch; 1414 1415 if (Sema::TemplateDeductionResult Result 1416 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1417 MemPtrParam->getPointeeType(), 1418 MemPtrArg->getPointeeType(), 1419 Info, Deduced, 1420 TDF & TDF_IgnoreQualifiers)) 1421 return Result; 1422 1423 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1424 QualType(MemPtrParam->getClass(), 0), 1425 QualType(MemPtrArg->getClass(), 0), 1426 Info, Deduced, 1427 TDF & TDF_IgnoreQualifiers); 1428 } 1429 1430 // (clang extension) 1431 // 1432 // type(^)(T) 1433 // T(^)() 1434 // T(^)(T) 1435 case Type::BlockPointer: { 1436 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param); 1437 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg); 1438 1439 if (!BlockPtrArg) 1440 return Sema::TDK_NonDeducedMismatch; 1441 1442 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1443 BlockPtrParam->getPointeeType(), 1444 BlockPtrArg->getPointeeType(), 1445 Info, Deduced, 0); 1446 } 1447 1448 // (clang extension) 1449 // 1450 // T __attribute__(((ext_vector_type(<integral constant>)))) 1451 case Type::ExtVector: { 1452 const ExtVectorType *VectorParam = cast<ExtVectorType>(Param); 1453 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) { 1454 // Make sure that the vectors have the same number of elements. 1455 if (VectorParam->getNumElements() != VectorArg->getNumElements()) 1456 return Sema::TDK_NonDeducedMismatch; 1457 1458 // Perform deduction on the element types. 1459 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1460 VectorParam->getElementType(), 1461 VectorArg->getElementType(), 1462 Info, Deduced, TDF); 1463 } 1464 1465 if (const DependentSizedExtVectorType *VectorArg 1466 = dyn_cast<DependentSizedExtVectorType>(Arg)) { 1467 // We can't check the number of elements, since the argument has a 1468 // dependent number of elements. This can only occur during partial 1469 // ordering. 1470 1471 // Perform deduction on the element types. 1472 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1473 VectorParam->getElementType(), 1474 VectorArg->getElementType(), 1475 Info, Deduced, TDF); 1476 } 1477 1478 return Sema::TDK_NonDeducedMismatch; 1479 } 1480 1481 // (clang extension) 1482 // 1483 // T __attribute__(((ext_vector_type(N)))) 1484 case Type::DependentSizedExtVector: { 1485 const DependentSizedExtVectorType *VectorParam 1486 = cast<DependentSizedExtVectorType>(Param); 1487 1488 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) { 1489 // Perform deduction on the element types. 1490 if (Sema::TemplateDeductionResult Result 1491 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1492 VectorParam->getElementType(), 1493 VectorArg->getElementType(), 1494 Info, Deduced, TDF)) 1495 return Result; 1496 1497 // Perform deduction on the vector size, if we can. 1498 NonTypeTemplateParmDecl *NTTP 1499 = getDeducedParameterFromExpr(VectorParam->getSizeExpr()); 1500 if (!NTTP) 1501 return Sema::TDK_Success; 1502 1503 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false); 1504 ArgSize = VectorArg->getNumElements(); 1505 return DeduceNonTypeTemplateArgument(S, NTTP, ArgSize, S.Context.IntTy, 1506 false, Info, Deduced); 1507 } 1508 1509 if (const DependentSizedExtVectorType *VectorArg 1510 = dyn_cast<DependentSizedExtVectorType>(Arg)) { 1511 // Perform deduction on the element types. 1512 if (Sema::TemplateDeductionResult Result 1513 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1514 VectorParam->getElementType(), 1515 VectorArg->getElementType(), 1516 Info, Deduced, TDF)) 1517 return Result; 1518 1519 // Perform deduction on the vector size, if we can. 1520 NonTypeTemplateParmDecl *NTTP 1521 = getDeducedParameterFromExpr(VectorParam->getSizeExpr()); 1522 if (!NTTP) 1523 return Sema::TDK_Success; 1524 1525 return DeduceNonTypeTemplateArgument(S, NTTP, VectorArg->getSizeExpr(), 1526 Info, Deduced); 1527 } 1528 1529 return Sema::TDK_NonDeducedMismatch; 1530 } 1531 1532 case Type::TypeOfExpr: 1533 case Type::TypeOf: 1534 case Type::DependentName: 1535 case Type::UnresolvedUsing: 1536 case Type::Decltype: 1537 case Type::UnaryTransform: 1538 case Type::Auto: 1539 case Type::DependentTemplateSpecialization: 1540 case Type::PackExpansion: 1541 // No template argument deduction for these types 1542 return Sema::TDK_Success; 1543 } 1544 1545 llvm_unreachable("Invalid Type Class!"); 1546} 1547 1548static Sema::TemplateDeductionResult 1549DeduceTemplateArguments(Sema &S, 1550 TemplateParameterList *TemplateParams, 1551 const TemplateArgument &Param, 1552 TemplateArgument Arg, 1553 TemplateDeductionInfo &Info, 1554 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 1555 // If the template argument is a pack expansion, perform template argument 1556 // deduction against the pattern of that expansion. This only occurs during 1557 // partial ordering. 1558 if (Arg.isPackExpansion()) 1559 Arg = Arg.getPackExpansionPattern(); 1560 1561 switch (Param.getKind()) { 1562 case TemplateArgument::Null: 1563 llvm_unreachable("Null template argument in parameter list"); 1564 1565 case TemplateArgument::Type: 1566 if (Arg.getKind() == TemplateArgument::Type) 1567 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 1568 Param.getAsType(), 1569 Arg.getAsType(), 1570 Info, Deduced, 0); 1571 Info.FirstArg = Param; 1572 Info.SecondArg = Arg; 1573 return Sema::TDK_NonDeducedMismatch; 1574 1575 case TemplateArgument::Template: 1576 if (Arg.getKind() == TemplateArgument::Template) 1577 return DeduceTemplateArguments(S, TemplateParams, 1578 Param.getAsTemplate(), 1579 Arg.getAsTemplate(), Info, Deduced); 1580 Info.FirstArg = Param; 1581 Info.SecondArg = Arg; 1582 return Sema::TDK_NonDeducedMismatch; 1583 1584 case TemplateArgument::TemplateExpansion: 1585 llvm_unreachable("caller should handle pack expansions"); 1586 1587 case TemplateArgument::Declaration: 1588 if (Arg.getKind() == TemplateArgument::Declaration && 1589 Param.getAsDecl()->getCanonicalDecl() == 1590 Arg.getAsDecl()->getCanonicalDecl()) 1591 return Sema::TDK_Success; 1592 1593 Info.FirstArg = Param; 1594 Info.SecondArg = Arg; 1595 return Sema::TDK_NonDeducedMismatch; 1596 1597 case TemplateArgument::Integral: 1598 if (Arg.getKind() == TemplateArgument::Integral) { 1599 if (hasSameExtendedValue(*Param.getAsIntegral(), *Arg.getAsIntegral())) 1600 return Sema::TDK_Success; 1601 1602 Info.FirstArg = Param; 1603 Info.SecondArg = Arg; 1604 return Sema::TDK_NonDeducedMismatch; 1605 } 1606 1607 if (Arg.getKind() == TemplateArgument::Expression) { 1608 Info.FirstArg = Param; 1609 Info.SecondArg = Arg; 1610 return Sema::TDK_NonDeducedMismatch; 1611 } 1612 1613 Info.FirstArg = Param; 1614 Info.SecondArg = Arg; 1615 return Sema::TDK_NonDeducedMismatch; 1616 1617 case TemplateArgument::Expression: { 1618 if (NonTypeTemplateParmDecl *NTTP 1619 = getDeducedParameterFromExpr(Param.getAsExpr())) { 1620 if (Arg.getKind() == TemplateArgument::Integral) 1621 return DeduceNonTypeTemplateArgument(S, NTTP, 1622 *Arg.getAsIntegral(), 1623 Arg.getIntegralType(), 1624 /*ArrayBound=*/false, 1625 Info, Deduced); 1626 if (Arg.getKind() == TemplateArgument::Expression) 1627 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsExpr(), 1628 Info, Deduced); 1629 if (Arg.getKind() == TemplateArgument::Declaration) 1630 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsDecl(), 1631 Info, Deduced); 1632 1633 Info.FirstArg = Param; 1634 Info.SecondArg = Arg; 1635 return Sema::TDK_NonDeducedMismatch; 1636 } 1637 1638 // Can't deduce anything, but that's okay. 1639 return Sema::TDK_Success; 1640 } 1641 case TemplateArgument::Pack: 1642 llvm_unreachable("Argument packs should be expanded by the caller!"); 1643 } 1644 1645 llvm_unreachable("Invalid TemplateArgument Kind!"); 1646} 1647 1648/// \brief Determine whether there is a template argument to be used for 1649/// deduction. 1650/// 1651/// This routine "expands" argument packs in-place, overriding its input 1652/// parameters so that \c Args[ArgIdx] will be the available template argument. 1653/// 1654/// \returns true if there is another template argument (which will be at 1655/// \c Args[ArgIdx]), false otherwise. 1656static bool hasTemplateArgumentForDeduction(const TemplateArgument *&Args, 1657 unsigned &ArgIdx, 1658 unsigned &NumArgs) { 1659 if (ArgIdx == NumArgs) 1660 return false; 1661 1662 const TemplateArgument &Arg = Args[ArgIdx]; 1663 if (Arg.getKind() != TemplateArgument::Pack) 1664 return true; 1665 1666 assert(ArgIdx == NumArgs - 1 && "Pack not at the end of argument list?"); 1667 Args = Arg.pack_begin(); 1668 NumArgs = Arg.pack_size(); 1669 ArgIdx = 0; 1670 return ArgIdx < NumArgs; 1671} 1672 1673/// \brief Determine whether the given set of template arguments has a pack 1674/// expansion that is not the last template argument. 1675static bool hasPackExpansionBeforeEnd(const TemplateArgument *Args, 1676 unsigned NumArgs) { 1677 unsigned ArgIdx = 0; 1678 while (ArgIdx < NumArgs) { 1679 const TemplateArgument &Arg = Args[ArgIdx]; 1680 1681 // Unwrap argument packs. 1682 if (Args[ArgIdx].getKind() == TemplateArgument::Pack) { 1683 Args = Arg.pack_begin(); 1684 NumArgs = Arg.pack_size(); 1685 ArgIdx = 0; 1686 continue; 1687 } 1688 1689 ++ArgIdx; 1690 if (ArgIdx == NumArgs) 1691 return false; 1692 1693 if (Arg.isPackExpansion()) 1694 return true; 1695 } 1696 1697 return false; 1698} 1699 1700static Sema::TemplateDeductionResult 1701DeduceTemplateArguments(Sema &S, 1702 TemplateParameterList *TemplateParams, 1703 const TemplateArgument *Params, unsigned NumParams, 1704 const TemplateArgument *Args, unsigned NumArgs, 1705 TemplateDeductionInfo &Info, 1706 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1707 bool NumberOfArgumentsMustMatch) { 1708 // C++0x [temp.deduct.type]p9: 1709 // If the template argument list of P contains a pack expansion that is not 1710 // the last template argument, the entire template argument list is a 1711 // non-deduced context. 1712 if (hasPackExpansionBeforeEnd(Params, NumParams)) 1713 return Sema::TDK_Success; 1714 1715 // C++0x [temp.deduct.type]p9: 1716 // If P has a form that contains <T> or <i>, then each argument Pi of the 1717 // respective template argument list P is compared with the corresponding 1718 // argument Ai of the corresponding template argument list of A. 1719 unsigned ArgIdx = 0, ParamIdx = 0; 1720 for (; hasTemplateArgumentForDeduction(Params, ParamIdx, NumParams); 1721 ++ParamIdx) { 1722 if (!Params[ParamIdx].isPackExpansion()) { 1723 // The simple case: deduce template arguments by matching Pi and Ai. 1724 1725 // Check whether we have enough arguments. 1726 if (!hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) 1727 return NumberOfArgumentsMustMatch? Sema::TDK_NonDeducedMismatch 1728 : Sema::TDK_Success; 1729 1730 if (Args[ArgIdx].isPackExpansion()) { 1731 // FIXME: We follow the logic of C++0x [temp.deduct.type]p22 here, 1732 // but applied to pack expansions that are template arguments. 1733 return Sema::TDK_NonDeducedMismatch; 1734 } 1735 1736 // Perform deduction for this Pi/Ai pair. 1737 if (Sema::TemplateDeductionResult Result 1738 = DeduceTemplateArguments(S, TemplateParams, 1739 Params[ParamIdx], Args[ArgIdx], 1740 Info, Deduced)) 1741 return Result; 1742 1743 // Move to the next argument. 1744 ++ArgIdx; 1745 continue; 1746 } 1747 1748 // The parameter is a pack expansion. 1749 1750 // C++0x [temp.deduct.type]p9: 1751 // If Pi is a pack expansion, then the pattern of Pi is compared with 1752 // each remaining argument in the template argument list of A. Each 1753 // comparison deduces template arguments for subsequent positions in the 1754 // template parameter packs expanded by Pi. 1755 TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern(); 1756 1757 // Compute the set of template parameter indices that correspond to 1758 // parameter packs expanded by the pack expansion. 1759 SmallVector<unsigned, 2> PackIndices; 1760 { 1761 llvm::SmallBitVector SawIndices(TemplateParams->size()); 1762 SmallVector<UnexpandedParameterPack, 2> Unexpanded; 1763 S.collectUnexpandedParameterPacks(Pattern, Unexpanded); 1764 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { 1765 unsigned Depth, Index; 1766 llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); 1767 if (Depth == 0 && !SawIndices[Index]) { 1768 SawIndices[Index] = true; 1769 PackIndices.push_back(Index); 1770 } 1771 } 1772 } 1773 assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); 1774 1775 // FIXME: If there are no remaining arguments, we can bail out early 1776 // and set any deduced parameter packs to an empty argument pack. 1777 // The latter part of this is a (minor) correctness issue. 1778 1779 // Save the deduced template arguments for each parameter pack expanded 1780 // by this pack expansion, then clear out the deduction. 1781 SmallVector<DeducedTemplateArgument, 2> 1782 SavedPacks(PackIndices.size()); 1783 SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2> 1784 NewlyDeducedPacks(PackIndices.size()); 1785 PrepareArgumentPackDeduction(S, Deduced, PackIndices, SavedPacks, 1786 NewlyDeducedPacks); 1787 1788 // Keep track of the deduced template arguments for each parameter pack 1789 // expanded by this pack expansion (the outer index) and for each 1790 // template argument (the inner SmallVectors). 1791 bool HasAnyArguments = false; 1792 while (hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) { 1793 HasAnyArguments = true; 1794 1795 // Deduce template arguments from the pattern. 1796 if (Sema::TemplateDeductionResult Result 1797 = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx], 1798 Info, Deduced)) 1799 return Result; 1800 1801 // Capture the deduced template arguments for each parameter pack expanded 1802 // by this pack expansion, add them to the list of arguments we've deduced 1803 // for that pack, then clear out the deduced argument. 1804 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 1805 DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; 1806 if (!DeducedArg.isNull()) { 1807 NewlyDeducedPacks[I].push_back(DeducedArg); 1808 DeducedArg = DeducedTemplateArgument(); 1809 } 1810 } 1811 1812 ++ArgIdx; 1813 } 1814 1815 // Build argument packs for each of the parameter packs expanded by this 1816 // pack expansion. 1817 if (Sema::TemplateDeductionResult Result 1818 = FinishArgumentPackDeduction(S, TemplateParams, HasAnyArguments, 1819 Deduced, PackIndices, SavedPacks, 1820 NewlyDeducedPacks, Info)) 1821 return Result; 1822 } 1823 1824 // If there is an argument remaining, then we had too many arguments. 1825 if (NumberOfArgumentsMustMatch && 1826 hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) 1827 return Sema::TDK_NonDeducedMismatch; 1828 1829 return Sema::TDK_Success; 1830} 1831 1832static Sema::TemplateDeductionResult 1833DeduceTemplateArguments(Sema &S, 1834 TemplateParameterList *TemplateParams, 1835 const TemplateArgumentList &ParamList, 1836 const TemplateArgumentList &ArgList, 1837 TemplateDeductionInfo &Info, 1838 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 1839 return DeduceTemplateArguments(S, TemplateParams, 1840 ParamList.data(), ParamList.size(), 1841 ArgList.data(), ArgList.size(), 1842 Info, Deduced); 1843} 1844 1845/// \brief Determine whether two template arguments are the same. 1846static bool isSameTemplateArg(ASTContext &Context, 1847 const TemplateArgument &X, 1848 const TemplateArgument &Y) { 1849 if (X.getKind() != Y.getKind()) 1850 return false; 1851 1852 switch (X.getKind()) { 1853 case TemplateArgument::Null: 1854 llvm_unreachable("Comparing NULL template argument"); 1855 1856 case TemplateArgument::Type: 1857 return Context.getCanonicalType(X.getAsType()) == 1858 Context.getCanonicalType(Y.getAsType()); 1859 1860 case TemplateArgument::Declaration: 1861 return X.getAsDecl()->getCanonicalDecl() == 1862 Y.getAsDecl()->getCanonicalDecl(); 1863 1864 case TemplateArgument::Template: 1865 case TemplateArgument::TemplateExpansion: 1866 return Context.getCanonicalTemplateName( 1867 X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() == 1868 Context.getCanonicalTemplateName( 1869 Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer(); 1870 1871 case TemplateArgument::Integral: 1872 return *X.getAsIntegral() == *Y.getAsIntegral(); 1873 1874 case TemplateArgument::Expression: { 1875 llvm::FoldingSetNodeID XID, YID; 1876 X.getAsExpr()->Profile(XID, Context, true); 1877 Y.getAsExpr()->Profile(YID, Context, true); 1878 return XID == YID; 1879 } 1880 1881 case TemplateArgument::Pack: 1882 if (X.pack_size() != Y.pack_size()) 1883 return false; 1884 1885 for (TemplateArgument::pack_iterator XP = X.pack_begin(), 1886 XPEnd = X.pack_end(), 1887 YP = Y.pack_begin(); 1888 XP != XPEnd; ++XP, ++YP) 1889 if (!isSameTemplateArg(Context, *XP, *YP)) 1890 return false; 1891 1892 return true; 1893 } 1894 1895 llvm_unreachable("Invalid TemplateArgument Kind!"); 1896} 1897 1898/// \brief Allocate a TemplateArgumentLoc where all locations have 1899/// been initialized to the given location. 1900/// 1901/// \param S The semantic analysis object. 1902/// 1903/// \param The template argument we are producing template argument 1904/// location information for. 1905/// 1906/// \param NTTPType For a declaration template argument, the type of 1907/// the non-type template parameter that corresponds to this template 1908/// argument. 1909/// 1910/// \param Loc The source location to use for the resulting template 1911/// argument. 1912static TemplateArgumentLoc 1913getTrivialTemplateArgumentLoc(Sema &S, 1914 const TemplateArgument &Arg, 1915 QualType NTTPType, 1916 SourceLocation Loc) { 1917 switch (Arg.getKind()) { 1918 case TemplateArgument::Null: 1919 llvm_unreachable("Can't get a NULL template argument here"); 1920 1921 case TemplateArgument::Type: 1922 return TemplateArgumentLoc(Arg, 1923 S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); 1924 1925 case TemplateArgument::Declaration: { 1926 Expr *E 1927 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 1928 .takeAs<Expr>(); 1929 return TemplateArgumentLoc(TemplateArgument(E), E); 1930 } 1931 1932 case TemplateArgument::Integral: { 1933 Expr *E 1934 = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>(); 1935 return TemplateArgumentLoc(TemplateArgument(E), E); 1936 } 1937 1938 case TemplateArgument::Template: 1939 case TemplateArgument::TemplateExpansion: { 1940 NestedNameSpecifierLocBuilder Builder; 1941 TemplateName Template = Arg.getAsTemplate(); 1942 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) 1943 Builder.MakeTrivial(S.Context, DTN->getQualifier(), Loc); 1944 else if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName()) 1945 Builder.MakeTrivial(S.Context, QTN->getQualifier(), Loc); 1946 1947 if (Arg.getKind() == TemplateArgument::Template) 1948 return TemplateArgumentLoc(Arg, 1949 Builder.getWithLocInContext(S.Context), 1950 Loc); 1951 1952 1953 return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(S.Context), 1954 Loc, Loc); 1955 } 1956 1957 case TemplateArgument::Expression: 1958 return TemplateArgumentLoc(Arg, Arg.getAsExpr()); 1959 1960 case TemplateArgument::Pack: 1961 return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo()); 1962 } 1963 1964 llvm_unreachable("Invalid TemplateArgument Kind!"); 1965} 1966 1967 1968/// \brief Convert the given deduced template argument and add it to the set of 1969/// fully-converted template arguments. 1970static bool ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param, 1971 DeducedTemplateArgument Arg, 1972 NamedDecl *Template, 1973 QualType NTTPType, 1974 unsigned ArgumentPackIndex, 1975 TemplateDeductionInfo &Info, 1976 bool InFunctionTemplate, 1977 SmallVectorImpl<TemplateArgument> &Output) { 1978 if (Arg.getKind() == TemplateArgument::Pack) { 1979 // This is a template argument pack, so check each of its arguments against 1980 // the template parameter. 1981 SmallVector<TemplateArgument, 2> PackedArgsBuilder; 1982 for (TemplateArgument::pack_iterator PA = Arg.pack_begin(), 1983 PAEnd = Arg.pack_end(); 1984 PA != PAEnd; ++PA) { 1985 // When converting the deduced template argument, append it to the 1986 // general output list. We need to do this so that the template argument 1987 // checking logic has all of the prior template arguments available. 1988 DeducedTemplateArgument InnerArg(*PA); 1989 InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound()); 1990 if (ConvertDeducedTemplateArgument(S, Param, InnerArg, Template, 1991 NTTPType, PackedArgsBuilder.size(), 1992 Info, InFunctionTemplate, Output)) 1993 return true; 1994 1995 // Move the converted template argument into our argument pack. 1996 PackedArgsBuilder.push_back(Output.back()); 1997 Output.pop_back(); 1998 } 1999 2000 // Create the resulting argument pack. 2001 Output.push_back(TemplateArgument::CreatePackCopy(S.Context, 2002 PackedArgsBuilder.data(), 2003 PackedArgsBuilder.size())); 2004 return false; 2005 } 2006 2007 // Convert the deduced template argument into a template 2008 // argument that we can check, almost as if the user had written 2009 // the template argument explicitly. 2010 TemplateArgumentLoc ArgLoc = getTrivialTemplateArgumentLoc(S, Arg, NTTPType, 2011 Info.getLocation()); 2012 2013 // Check the template argument, converting it as necessary. 2014 return S.CheckTemplateArgument(Param, ArgLoc, 2015 Template, 2016 Template->getLocation(), 2017 Template->getSourceRange().getEnd(), 2018 ArgumentPackIndex, 2019 Output, 2020 InFunctionTemplate 2021 ? (Arg.wasDeducedFromArrayBound() 2022 ? Sema::CTAK_DeducedFromArrayBound 2023 : Sema::CTAK_Deduced) 2024 : Sema::CTAK_Specified); 2025} 2026 2027/// Complete template argument deduction for a class template partial 2028/// specialization. 2029static Sema::TemplateDeductionResult 2030FinishTemplateArgumentDeduction(Sema &S, 2031 ClassTemplatePartialSpecializationDecl *Partial, 2032 const TemplateArgumentList &TemplateArgs, 2033 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2034 TemplateDeductionInfo &Info) { 2035 // Unevaluated SFINAE context. 2036 EnterExpressionEvaluationContext Unevaluated(S, Sema::Unevaluated); 2037 Sema::SFINAETrap Trap(S); 2038 2039 Sema::ContextRAII SavedContext(S, Partial); 2040 2041 // C++ [temp.deduct.type]p2: 2042 // [...] or if any template argument remains neither deduced nor 2043 // explicitly specified, template argument deduction fails. 2044 SmallVector<TemplateArgument, 4> Builder; 2045 TemplateParameterList *PartialParams = Partial->getTemplateParameters(); 2046 for (unsigned I = 0, N = PartialParams->size(); I != N; ++I) { 2047 NamedDecl *Param = PartialParams->getParam(I); 2048 if (Deduced[I].isNull()) { 2049 Info.Param = makeTemplateParameter(Param); 2050 return Sema::TDK_Incomplete; 2051 } 2052 2053 // We have deduced this argument, so it still needs to be 2054 // checked and converted. 2055 2056 // First, for a non-type template parameter type that is 2057 // initialized by a declaration, we need the type of the 2058 // corresponding non-type template parameter. 2059 QualType NTTPType; 2060 if (NonTypeTemplateParmDecl *NTTP 2061 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 2062 NTTPType = NTTP->getType(); 2063 if (NTTPType->isDependentType()) { 2064 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, 2065 Builder.data(), Builder.size()); 2066 NTTPType = S.SubstType(NTTPType, 2067 MultiLevelTemplateArgumentList(TemplateArgs), 2068 NTTP->getLocation(), 2069 NTTP->getDeclName()); 2070 if (NTTPType.isNull()) { 2071 Info.Param = makeTemplateParameter(Param); 2072 // FIXME: These template arguments are temporary. Free them! 2073 Info.reset(TemplateArgumentList::CreateCopy(S.Context, 2074 Builder.data(), 2075 Builder.size())); 2076 return Sema::TDK_SubstitutionFailure; 2077 } 2078 } 2079 } 2080 2081 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], 2082 Partial, NTTPType, 0, Info, false, 2083 Builder)) { 2084 Info.Param = makeTemplateParameter(Param); 2085 // FIXME: These template arguments are temporary. Free them! 2086 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder.data(), 2087 Builder.size())); 2088 return Sema::TDK_SubstitutionFailure; 2089 } 2090 } 2091 2092 // Form the template argument list from the deduced template arguments. 2093 TemplateArgumentList *DeducedArgumentList 2094 = TemplateArgumentList::CreateCopy(S.Context, Builder.data(), 2095 Builder.size()); 2096 2097 Info.reset(DeducedArgumentList); 2098 2099 // Substitute the deduced template arguments into the template 2100 // arguments of the class template partial specialization, and 2101 // verify that the instantiated template arguments are both valid 2102 // and are equivalent to the template arguments originally provided 2103 // to the class template. 2104 LocalInstantiationScope InstScope(S); 2105 ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); 2106 const TemplateArgumentLoc *PartialTemplateArgs 2107 = Partial->getTemplateArgsAsWritten(); 2108 2109 // Note that we don't provide the langle and rangle locations. 2110 TemplateArgumentListInfo InstArgs; 2111 2112 if (S.Subst(PartialTemplateArgs, 2113 Partial->getNumTemplateArgsAsWritten(), 2114 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) { 2115 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx; 2116 if (ParamIdx >= Partial->getTemplateParameters()->size()) 2117 ParamIdx = Partial->getTemplateParameters()->size() - 1; 2118 2119 Decl *Param 2120 = const_cast<NamedDecl *>( 2121 Partial->getTemplateParameters()->getParam(ParamIdx)); 2122 Info.Param = makeTemplateParameter(Param); 2123 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument(); 2124 return Sema::TDK_SubstitutionFailure; 2125 } 2126 2127 SmallVector<TemplateArgument, 4> ConvertedInstArgs; 2128 if (S.CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(), 2129 InstArgs, false, ConvertedInstArgs)) 2130 return Sema::TDK_SubstitutionFailure; 2131 2132 TemplateParameterList *TemplateParams 2133 = ClassTemplate->getTemplateParameters(); 2134 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) { 2135 TemplateArgument InstArg = ConvertedInstArgs.data()[I]; 2136 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) { 2137 Info.Param = makeTemplateParameter(TemplateParams->getParam(I)); 2138 Info.FirstArg = TemplateArgs[I]; 2139 Info.SecondArg = InstArg; 2140 return Sema::TDK_NonDeducedMismatch; 2141 } 2142 } 2143 2144 if (Trap.hasErrorOccurred()) 2145 return Sema::TDK_SubstitutionFailure; 2146 2147 return Sema::TDK_Success; 2148} 2149 2150/// \brief Perform template argument deduction to determine whether 2151/// the given template arguments match the given class template 2152/// partial specialization per C++ [temp.class.spec.match]. 2153Sema::TemplateDeductionResult 2154Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, 2155 const TemplateArgumentList &TemplateArgs, 2156 TemplateDeductionInfo &Info) { 2157 // C++ [temp.class.spec.match]p2: 2158 // A partial specialization matches a given actual template 2159 // argument list if the template arguments of the partial 2160 // specialization can be deduced from the actual template argument 2161 // list (14.8.2). 2162 2163 // Unevaluated SFINAE context. 2164 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 2165 SFINAETrap Trap(*this); 2166 2167 SmallVector<DeducedTemplateArgument, 4> Deduced; 2168 Deduced.resize(Partial->getTemplateParameters()->size()); 2169 if (TemplateDeductionResult Result 2170 = ::DeduceTemplateArguments(*this, 2171 Partial->getTemplateParameters(), 2172 Partial->getTemplateArgs(), 2173 TemplateArgs, Info, Deduced)) 2174 return Result; 2175 2176 InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, 2177 Deduced.data(), Deduced.size(), Info); 2178 if (Inst) 2179 return TDK_InstantiationDepth; 2180 2181 if (Trap.hasErrorOccurred()) 2182 return Sema::TDK_SubstitutionFailure; 2183 2184 return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs, 2185 Deduced, Info); 2186} 2187 2188/// \brief Determine whether the given type T is a simple-template-id type. 2189static bool isSimpleTemplateIdType(QualType T) { 2190 if (const TemplateSpecializationType *Spec 2191 = T->getAs<TemplateSpecializationType>()) 2192 return Spec->getTemplateName().getAsTemplateDecl() != 0; 2193 2194 return false; 2195} 2196 2197/// \brief Substitute the explicitly-provided template arguments into the 2198/// given function template according to C++ [temp.arg.explicit]. 2199/// 2200/// \param FunctionTemplate the function template into which the explicit 2201/// template arguments will be substituted. 2202/// 2203/// \param ExplicitTemplateArguments the explicitly-specified template 2204/// arguments. 2205/// 2206/// \param Deduced the deduced template arguments, which will be populated 2207/// with the converted and checked explicit template arguments. 2208/// 2209/// \param ParamTypes will be populated with the instantiated function 2210/// parameters. 2211/// 2212/// \param FunctionType if non-NULL, the result type of the function template 2213/// will also be instantiated and the pointed-to value will be updated with 2214/// the instantiated function type. 2215/// 2216/// \param Info if substitution fails for any reason, this object will be 2217/// populated with more information about the failure. 2218/// 2219/// \returns TDK_Success if substitution was successful, or some failure 2220/// condition. 2221Sema::TemplateDeductionResult 2222Sema::SubstituteExplicitTemplateArguments( 2223 FunctionTemplateDecl *FunctionTemplate, 2224 TemplateArgumentListInfo &ExplicitTemplateArgs, 2225 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2226 SmallVectorImpl<QualType> &ParamTypes, 2227 QualType *FunctionType, 2228 TemplateDeductionInfo &Info) { 2229 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2230 TemplateParameterList *TemplateParams 2231 = FunctionTemplate->getTemplateParameters(); 2232 2233 if (ExplicitTemplateArgs.size() == 0) { 2234 // No arguments to substitute; just copy over the parameter types and 2235 // fill in the function type. 2236 for (FunctionDecl::param_iterator P = Function->param_begin(), 2237 PEnd = Function->param_end(); 2238 P != PEnd; 2239 ++P) 2240 ParamTypes.push_back((*P)->getType()); 2241 2242 if (FunctionType) 2243 *FunctionType = Function->getType(); 2244 return TDK_Success; 2245 } 2246 2247 // Unevaluated SFINAE context. 2248 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 2249 SFINAETrap Trap(*this); 2250 2251 // C++ [temp.arg.explicit]p3: 2252 // Template arguments that are present shall be specified in the 2253 // declaration order of their corresponding template-parameters. The 2254 // template argument list shall not specify more template-arguments than 2255 // there are corresponding template-parameters. 2256 SmallVector<TemplateArgument, 4> Builder; 2257 2258 // Enter a new template instantiation context where we check the 2259 // explicitly-specified template arguments against this function template, 2260 // and then substitute them into the function parameter types. 2261 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 2262 FunctionTemplate, Deduced.data(), Deduced.size(), 2263 ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution, 2264 Info); 2265 if (Inst) 2266 return TDK_InstantiationDepth; 2267 2268 if (CheckTemplateArgumentList(FunctionTemplate, 2269 SourceLocation(), 2270 ExplicitTemplateArgs, 2271 true, 2272 Builder) || Trap.hasErrorOccurred()) { 2273 unsigned Index = Builder.size(); 2274 if (Index >= TemplateParams->size()) 2275 Index = TemplateParams->size() - 1; 2276 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index)); 2277 return TDK_InvalidExplicitArguments; 2278 } 2279 2280 // Form the template argument list from the explicitly-specified 2281 // template arguments. 2282 TemplateArgumentList *ExplicitArgumentList 2283 = TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size()); 2284 Info.reset(ExplicitArgumentList); 2285 2286 // Template argument deduction and the final substitution should be 2287 // done in the context of the templated declaration. Explicit 2288 // argument substitution, on the other hand, needs to happen in the 2289 // calling context. 2290 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 2291 2292 // If we deduced template arguments for a template parameter pack, 2293 // note that the template argument pack is partially substituted and record 2294 // the explicit template arguments. They'll be used as part of deduction 2295 // for this template parameter pack. 2296 for (unsigned I = 0, N = Builder.size(); I != N; ++I) { 2297 const TemplateArgument &Arg = Builder[I]; 2298 if (Arg.getKind() == TemplateArgument::Pack) { 2299 CurrentInstantiationScope->SetPartiallySubstitutedPack( 2300 TemplateParams->getParam(I), 2301 Arg.pack_begin(), 2302 Arg.pack_size()); 2303 break; 2304 } 2305 } 2306 2307 const FunctionProtoType *Proto 2308 = Function->getType()->getAs<FunctionProtoType>(); 2309 assert(Proto && "Function template does not have a prototype?"); 2310 2311 // Instantiate the types of each of the function parameters given the 2312 // explicitly-specified template arguments. If the function has a trailing 2313 // return type, substitute it after the arguments to ensure we substitute 2314 // in lexical order. 2315 if (Proto->hasTrailingReturn() && 2316 SubstParmTypes(Function->getLocation(), 2317 Function->param_begin(), Function->getNumParams(), 2318 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 2319 ParamTypes)) 2320 return TDK_SubstitutionFailure; 2321 2322 // Instantiate the return type. 2323 // FIXME: exception-specifications? 2324 QualType ResultType 2325 = SubstType(Proto->getResultType(), 2326 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 2327 Function->getTypeSpecStartLoc(), 2328 Function->getDeclName()); 2329 if (ResultType.isNull() || Trap.hasErrorOccurred()) 2330 return TDK_SubstitutionFailure; 2331 2332 // Instantiate the types of each of the function parameters given the 2333 // explicitly-specified template arguments if we didn't do so earlier. 2334 if (!Proto->hasTrailingReturn() && 2335 SubstParmTypes(Function->getLocation(), 2336 Function->param_begin(), Function->getNumParams(), 2337 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 2338 ParamTypes)) 2339 return TDK_SubstitutionFailure; 2340 2341 if (FunctionType) { 2342 *FunctionType = BuildFunctionType(ResultType, 2343 ParamTypes.data(), ParamTypes.size(), 2344 Proto->isVariadic(), 2345 Proto->hasTrailingReturn(), 2346 Proto->getTypeQuals(), 2347 Proto->getRefQualifier(), 2348 Function->getLocation(), 2349 Function->getDeclName(), 2350 Proto->getExtInfo()); 2351 if (FunctionType->isNull() || Trap.hasErrorOccurred()) 2352 return TDK_SubstitutionFailure; 2353 } 2354 2355 // C++ [temp.arg.explicit]p2: 2356 // Trailing template arguments that can be deduced (14.8.2) may be 2357 // omitted from the list of explicit template-arguments. If all of the 2358 // template arguments can be deduced, they may all be omitted; in this 2359 // case, the empty template argument list <> itself may also be omitted. 2360 // 2361 // Take all of the explicitly-specified arguments and put them into 2362 // the set of deduced template arguments. Explicitly-specified 2363 // parameter packs, however, will be set to NULL since the deduction 2364 // mechanisms handle explicitly-specified argument packs directly. 2365 Deduced.reserve(TemplateParams->size()); 2366 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) { 2367 const TemplateArgument &Arg = ExplicitArgumentList->get(I); 2368 if (Arg.getKind() == TemplateArgument::Pack) 2369 Deduced.push_back(DeducedTemplateArgument()); 2370 else 2371 Deduced.push_back(Arg); 2372 } 2373 2374 return TDK_Success; 2375} 2376 2377/// \brief Check whether the deduced argument type for a call to a function 2378/// template matches the actual argument type per C++ [temp.deduct.call]p4. 2379static bool 2380CheckOriginalCallArgDeduction(Sema &S, Sema::OriginalCallArg OriginalArg, 2381 QualType DeducedA) { 2382 ASTContext &Context = S.Context; 2383 2384 QualType A = OriginalArg.OriginalArgType; 2385 QualType OriginalParamType = OriginalArg.OriginalParamType; 2386 2387 // Check for type equality (top-level cv-qualifiers are ignored). 2388 if (Context.hasSameUnqualifiedType(A, DeducedA)) 2389 return false; 2390 2391 // Strip off references on the argument types; they aren't needed for 2392 // the following checks. 2393 if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>()) 2394 DeducedA = DeducedARef->getPointeeType(); 2395 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 2396 A = ARef->getPointeeType(); 2397 2398 // C++ [temp.deduct.call]p4: 2399 // [...] However, there are three cases that allow a difference: 2400 // - If the original P is a reference type, the deduced A (i.e., the 2401 // type referred to by the reference) can be more cv-qualified than 2402 // the transformed A. 2403 if (const ReferenceType *OriginalParamRef 2404 = OriginalParamType->getAs<ReferenceType>()) { 2405 // We don't want to keep the reference around any more. 2406 OriginalParamType = OriginalParamRef->getPointeeType(); 2407 2408 Qualifiers AQuals = A.getQualifiers(); 2409 Qualifiers DeducedAQuals = DeducedA.getQualifiers(); 2410 if (AQuals == DeducedAQuals) { 2411 // Qualifiers match; there's nothing to do. 2412 } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) { 2413 return true; 2414 } else { 2415 // Qualifiers are compatible, so have the argument type adopt the 2416 // deduced argument type's qualifiers as if we had performed the 2417 // qualification conversion. 2418 A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals); 2419 } 2420 } 2421 2422 // - The transformed A can be another pointer or pointer to member 2423 // type that can be converted to the deduced A via a qualification 2424 // conversion. 2425 // 2426 // Also allow conversions which merely strip [[noreturn]] from function types 2427 // (recursively) as an extension. 2428 // FIXME: Currently, this doesn't place nicely with qualfication conversions. 2429 bool ObjCLifetimeConversion = false; 2430 QualType ResultTy; 2431 if ((A->isAnyPointerType() || A->isMemberPointerType()) && 2432 (S.IsQualificationConversion(A, DeducedA, false, 2433 ObjCLifetimeConversion) || 2434 S.IsNoReturnConversion(A, DeducedA, ResultTy))) 2435 return false; 2436 2437 2438 // - If P is a class and P has the form simple-template-id, then the 2439 // transformed A can be a derived class of the deduced A. [...] 2440 // [...] Likewise, if P is a pointer to a class of the form 2441 // simple-template-id, the transformed A can be a pointer to a 2442 // derived class pointed to by the deduced A. 2443 if (const PointerType *OriginalParamPtr 2444 = OriginalParamType->getAs<PointerType>()) { 2445 if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) { 2446 if (const PointerType *APtr = A->getAs<PointerType>()) { 2447 if (A->getPointeeType()->isRecordType()) { 2448 OriginalParamType = OriginalParamPtr->getPointeeType(); 2449 DeducedA = DeducedAPtr->getPointeeType(); 2450 A = APtr->getPointeeType(); 2451 } 2452 } 2453 } 2454 } 2455 2456 if (Context.hasSameUnqualifiedType(A, DeducedA)) 2457 return false; 2458 2459 if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) && 2460 S.IsDerivedFrom(A, DeducedA)) 2461 return false; 2462 2463 return true; 2464} 2465 2466/// \brief Finish template argument deduction for a function template, 2467/// checking the deduced template arguments for completeness and forming 2468/// the function template specialization. 2469/// 2470/// \param OriginalCallArgs If non-NULL, the original call arguments against 2471/// which the deduced argument types should be compared. 2472Sema::TemplateDeductionResult 2473Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate, 2474 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2475 unsigned NumExplicitlySpecified, 2476 FunctionDecl *&Specialization, 2477 TemplateDeductionInfo &Info, 2478 SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs) { 2479 TemplateParameterList *TemplateParams 2480 = FunctionTemplate->getTemplateParameters(); 2481 2482 // Unevaluated SFINAE context. 2483 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 2484 SFINAETrap Trap(*this); 2485 2486 // Enter a new template instantiation context while we instantiate the 2487 // actual function declaration. 2488 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 2489 FunctionTemplate, Deduced.data(), Deduced.size(), 2490 ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution, 2491 Info); 2492 if (Inst) 2493 return TDK_InstantiationDepth; 2494 2495 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 2496 2497 // C++ [temp.deduct.type]p2: 2498 // [...] or if any template argument remains neither deduced nor 2499 // explicitly specified, template argument deduction fails. 2500 SmallVector<TemplateArgument, 4> Builder; 2501 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) { 2502 NamedDecl *Param = TemplateParams->getParam(I); 2503 2504 if (!Deduced[I].isNull()) { 2505 if (I < NumExplicitlySpecified) { 2506 // We have already fully type-checked and converted this 2507 // argument, because it was explicitly-specified. Just record the 2508 // presence of this argument. 2509 Builder.push_back(Deduced[I]); 2510 continue; 2511 } 2512 2513 // We have deduced this argument, so it still needs to be 2514 // checked and converted. 2515 2516 // First, for a non-type template parameter type that is 2517 // initialized by a declaration, we need the type of the 2518 // corresponding non-type template parameter. 2519 QualType NTTPType; 2520 if (NonTypeTemplateParmDecl *NTTP 2521 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 2522 NTTPType = NTTP->getType(); 2523 if (NTTPType->isDependentType()) { 2524 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, 2525 Builder.data(), Builder.size()); 2526 NTTPType = SubstType(NTTPType, 2527 MultiLevelTemplateArgumentList(TemplateArgs), 2528 NTTP->getLocation(), 2529 NTTP->getDeclName()); 2530 if (NTTPType.isNull()) { 2531 Info.Param = makeTemplateParameter(Param); 2532 // FIXME: These template arguments are temporary. Free them! 2533 Info.reset(TemplateArgumentList::CreateCopy(Context, 2534 Builder.data(), 2535 Builder.size())); 2536 return TDK_SubstitutionFailure; 2537 } 2538 } 2539 } 2540 2541 if (ConvertDeducedTemplateArgument(*this, Param, Deduced[I], 2542 FunctionTemplate, NTTPType, 0, Info, 2543 true, Builder)) { 2544 Info.Param = makeTemplateParameter(Param); 2545 // FIXME: These template arguments are temporary. Free them! 2546 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), 2547 Builder.size())); 2548 return TDK_SubstitutionFailure; 2549 } 2550 2551 continue; 2552 } 2553 2554 // C++0x [temp.arg.explicit]p3: 2555 // A trailing template parameter pack (14.5.3) not otherwise deduced will 2556 // be deduced to an empty sequence of template arguments. 2557 // FIXME: Where did the word "trailing" come from? 2558 if (Param->isTemplateParameterPack()) { 2559 // We may have had explicitly-specified template arguments for this 2560 // template parameter pack. If so, our empty deduction extends the 2561 // explicitly-specified set (C++0x [temp.arg.explicit]p9). 2562 const TemplateArgument *ExplicitArgs; 2563 unsigned NumExplicitArgs; 2564 if (CurrentInstantiationScope->getPartiallySubstitutedPack(&ExplicitArgs, 2565 &NumExplicitArgs) 2566 == Param) 2567 Builder.push_back(TemplateArgument(ExplicitArgs, NumExplicitArgs)); 2568 else 2569 Builder.push_back(TemplateArgument(0, 0)); 2570 2571 continue; 2572 } 2573 2574 // Substitute into the default template argument, if available. 2575 TemplateArgumentLoc DefArg 2576 = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate, 2577 FunctionTemplate->getLocation(), 2578 FunctionTemplate->getSourceRange().getEnd(), 2579 Param, 2580 Builder); 2581 2582 // If there was no default argument, deduction is incomplete. 2583 if (DefArg.getArgument().isNull()) { 2584 Info.Param = makeTemplateParameter( 2585 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 2586 return TDK_Incomplete; 2587 } 2588 2589 // Check whether we can actually use the default argument. 2590 if (CheckTemplateArgument(Param, DefArg, 2591 FunctionTemplate, 2592 FunctionTemplate->getLocation(), 2593 FunctionTemplate->getSourceRange().getEnd(), 2594 0, Builder, 2595 CTAK_Specified)) { 2596 Info.Param = makeTemplateParameter( 2597 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 2598 // FIXME: These template arguments are temporary. Free them! 2599 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), 2600 Builder.size())); 2601 return TDK_SubstitutionFailure; 2602 } 2603 2604 // If we get here, we successfully used the default template argument. 2605 } 2606 2607 // Form the template argument list from the deduced template arguments. 2608 TemplateArgumentList *DeducedArgumentList 2609 = TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size()); 2610 Info.reset(DeducedArgumentList); 2611 2612 // Substitute the deduced template arguments into the function template 2613 // declaration to produce the function template specialization. 2614 DeclContext *Owner = FunctionTemplate->getDeclContext(); 2615 if (FunctionTemplate->getFriendObjectKind()) 2616 Owner = FunctionTemplate->getLexicalDeclContext(); 2617 Specialization = cast_or_null<FunctionDecl>( 2618 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, 2619 MultiLevelTemplateArgumentList(*DeducedArgumentList))); 2620 if (!Specialization || Specialization->isInvalidDecl()) 2621 return TDK_SubstitutionFailure; 2622 2623 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() == 2624 FunctionTemplate->getCanonicalDecl()); 2625 2626 // If the template argument list is owned by the function template 2627 // specialization, release it. 2628 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList && 2629 !Trap.hasErrorOccurred()) 2630 Info.take(); 2631 2632 // There may have been an error that did not prevent us from constructing a 2633 // declaration. Mark the declaration invalid and return with a substitution 2634 // failure. 2635 if (Trap.hasErrorOccurred()) { 2636 Specialization->setInvalidDecl(true); 2637 return TDK_SubstitutionFailure; 2638 } 2639 2640 if (OriginalCallArgs) { 2641 // C++ [temp.deduct.call]p4: 2642 // In general, the deduction process attempts to find template argument 2643 // values that will make the deduced A identical to A (after the type A 2644 // is transformed as described above). [...] 2645 for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) { 2646 OriginalCallArg OriginalArg = (*OriginalCallArgs)[I]; 2647 unsigned ParamIdx = OriginalArg.ArgIdx; 2648 2649 if (ParamIdx >= Specialization->getNumParams()) 2650 continue; 2651 2652 QualType DeducedA = Specialization->getParamDecl(ParamIdx)->getType(); 2653 if (CheckOriginalCallArgDeduction(*this, OriginalArg, DeducedA)) 2654 return Sema::TDK_SubstitutionFailure; 2655 } 2656 } 2657 2658 // If we suppressed any diagnostics while performing template argument 2659 // deduction, and if we haven't already instantiated this declaration, 2660 // keep track of these diagnostics. They'll be emitted if this specialization 2661 // is actually used. 2662 if (Info.diag_begin() != Info.diag_end()) { 2663 llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, 1> >::iterator 2664 Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl()); 2665 if (Pos == SuppressedDiagnostics.end()) 2666 SuppressedDiagnostics[Specialization->getCanonicalDecl()] 2667 .append(Info.diag_begin(), Info.diag_end()); 2668 } 2669 2670 return TDK_Success; 2671} 2672 2673/// Gets the type of a function for template-argument-deducton 2674/// purposes when it's considered as part of an overload set. 2675static QualType GetTypeOfFunction(ASTContext &Context, 2676 const OverloadExpr::FindResult &R, 2677 FunctionDecl *Fn) { 2678 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) 2679 if (Method->isInstance()) { 2680 // An instance method that's referenced in a form that doesn't 2681 // look like a member pointer is just invalid. 2682 if (!R.HasFormOfMemberPointer) return QualType(); 2683 2684 return Context.getMemberPointerType(Fn->getType(), 2685 Context.getTypeDeclType(Method->getParent()).getTypePtr()); 2686 } 2687 2688 if (!R.IsAddressOfOperand) return Fn->getType(); 2689 return Context.getPointerType(Fn->getType()); 2690} 2691 2692/// Apply the deduction rules for overload sets. 2693/// 2694/// \return the null type if this argument should be treated as an 2695/// undeduced context 2696static QualType 2697ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, 2698 Expr *Arg, QualType ParamType, 2699 bool ParamWasReference) { 2700 2701 OverloadExpr::FindResult R = OverloadExpr::find(Arg); 2702 2703 OverloadExpr *Ovl = R.Expression; 2704 2705 // C++0x [temp.deduct.call]p4 2706 unsigned TDF = 0; 2707 if (ParamWasReference) 2708 TDF |= TDF_ParamWithReferenceType; 2709 if (R.IsAddressOfOperand) 2710 TDF |= TDF_IgnoreQualifiers; 2711 2712 // If there were explicit template arguments, we can only find 2713 // something via C++ [temp.arg.explicit]p3, i.e. if the arguments 2714 // unambiguously name a full specialization. 2715 if (Ovl->hasExplicitTemplateArgs()) { 2716 // But we can still look for an explicit specialization. 2717 if (FunctionDecl *ExplicitSpec 2718 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 2719 return GetTypeOfFunction(S.Context, R, ExplicitSpec); 2720 return QualType(); 2721 } 2722 2723 // C++0x [temp.deduct.call]p6: 2724 // When P is a function type, pointer to function type, or pointer 2725 // to member function type: 2726 2727 if (!ParamType->isFunctionType() && 2728 !ParamType->isFunctionPointerType() && 2729 !ParamType->isMemberFunctionPointerType()) 2730 return QualType(); 2731 2732 QualType Match; 2733 for (UnresolvedSetIterator I = Ovl->decls_begin(), 2734 E = Ovl->decls_end(); I != E; ++I) { 2735 NamedDecl *D = (*I)->getUnderlyingDecl(); 2736 2737 // - If the argument is an overload set containing one or more 2738 // function templates, the parameter is treated as a 2739 // non-deduced context. 2740 if (isa<FunctionTemplateDecl>(D)) 2741 return QualType(); 2742 2743 FunctionDecl *Fn = cast<FunctionDecl>(D); 2744 QualType ArgType = GetTypeOfFunction(S.Context, R, Fn); 2745 if (ArgType.isNull()) continue; 2746 2747 // Function-to-pointer conversion. 2748 if (!ParamWasReference && ParamType->isPointerType() && 2749 ArgType->isFunctionType()) 2750 ArgType = S.Context.getPointerType(ArgType); 2751 2752 // - If the argument is an overload set (not containing function 2753 // templates), trial argument deduction is attempted using each 2754 // of the members of the set. If deduction succeeds for only one 2755 // of the overload set members, that member is used as the 2756 // argument value for the deduction. If deduction succeeds for 2757 // more than one member of the overload set the parameter is 2758 // treated as a non-deduced context. 2759 2760 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 2761 // Type deduction is done independently for each P/A pair, and 2762 // the deduced template argument values are then combined. 2763 // So we do not reject deductions which were made elsewhere. 2764 SmallVector<DeducedTemplateArgument, 8> 2765 Deduced(TemplateParams->size()); 2766 TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 2767 Sema::TemplateDeductionResult Result 2768 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 2769 ArgType, Info, Deduced, TDF); 2770 if (Result) continue; 2771 if (!Match.isNull()) return QualType(); 2772 Match = ArgType; 2773 } 2774 2775 return Match; 2776} 2777 2778/// \brief Perform the adjustments to the parameter and argument types 2779/// described in C++ [temp.deduct.call]. 2780/// 2781/// \returns true if the caller should not attempt to perform any template 2782/// argument deduction based on this P/A pair. 2783static bool AdjustFunctionParmAndArgTypesForDeduction(Sema &S, 2784 TemplateParameterList *TemplateParams, 2785 QualType &ParamType, 2786 QualType &ArgType, 2787 Expr *Arg, 2788 unsigned &TDF) { 2789 // C++0x [temp.deduct.call]p3: 2790 // If P is a cv-qualified type, the top level cv-qualifiers of P's type 2791 // are ignored for type deduction. 2792 if (ParamType.hasQualifiers()) 2793 ParamType = ParamType.getUnqualifiedType(); 2794 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>(); 2795 if (ParamRefType) { 2796 QualType PointeeType = ParamRefType->getPointeeType(); 2797 2798 // If the argument has incomplete array type, try to complete it's type. 2799 if (ArgType->isIncompleteArrayType() && 2800 !S.RequireCompleteExprType(Arg, S.PDiag(), 2801 std::make_pair(SourceLocation(), S.PDiag()))) 2802 ArgType = Arg->getType(); 2803 2804 // [C++0x] If P is an rvalue reference to a cv-unqualified 2805 // template parameter and the argument is an lvalue, the type 2806 // "lvalue reference to A" is used in place of A for type 2807 // deduction. 2808 if (isa<RValueReferenceType>(ParamType)) { 2809 if (!PointeeType.getQualifiers() && 2810 isa<TemplateTypeParmType>(PointeeType) && 2811 Arg->Classify(S.Context).isLValue() && 2812 Arg->getType() != S.Context.OverloadTy && 2813 Arg->getType() != S.Context.BoundMemberTy) 2814 ArgType = S.Context.getLValueReferenceType(ArgType); 2815 } 2816 2817 // [...] If P is a reference type, the type referred to by P is used 2818 // for type deduction. 2819 ParamType = PointeeType; 2820 } 2821 2822 // Overload sets usually make this parameter an undeduced 2823 // context, but there are sometimes special circumstances. 2824 if (ArgType == S.Context.OverloadTy) { 2825 ArgType = ResolveOverloadForDeduction(S, TemplateParams, 2826 Arg, ParamType, 2827 ParamRefType != 0); 2828 if (ArgType.isNull()) 2829 return true; 2830 } 2831 2832 if (ParamRefType) { 2833 // C++0x [temp.deduct.call]p3: 2834 // [...] If P is of the form T&&, where T is a template parameter, and 2835 // the argument is an lvalue, the type A& is used in place of A for 2836 // type deduction. 2837 if (ParamRefType->isRValueReferenceType() && 2838 ParamRefType->getAs<TemplateTypeParmType>() && 2839 Arg->isLValue()) 2840 ArgType = S.Context.getLValueReferenceType(ArgType); 2841 } else { 2842 // C++ [temp.deduct.call]p2: 2843 // If P is not a reference type: 2844 // - If A is an array type, the pointer type produced by the 2845 // array-to-pointer standard conversion (4.2) is used in place of 2846 // A for type deduction; otherwise, 2847 if (ArgType->isArrayType()) 2848 ArgType = S.Context.getArrayDecayedType(ArgType); 2849 // - If A is a function type, the pointer type produced by the 2850 // function-to-pointer standard conversion (4.3) is used in place 2851 // of A for type deduction; otherwise, 2852 else if (ArgType->isFunctionType()) 2853 ArgType = S.Context.getPointerType(ArgType); 2854 else { 2855 // - If A is a cv-qualified type, the top level cv-qualifiers of A's 2856 // type are ignored for type deduction. 2857 ArgType = ArgType.getUnqualifiedType(); 2858 } 2859 } 2860 2861 // C++0x [temp.deduct.call]p4: 2862 // In general, the deduction process attempts to find template argument 2863 // values that will make the deduced A identical to A (after the type A 2864 // is transformed as described above). [...] 2865 TDF = TDF_SkipNonDependent; 2866 2867 // - If the original P is a reference type, the deduced A (i.e., the 2868 // type referred to by the reference) can be more cv-qualified than 2869 // the transformed A. 2870 if (ParamRefType) 2871 TDF |= TDF_ParamWithReferenceType; 2872 // - The transformed A can be another pointer or pointer to member 2873 // type that can be converted to the deduced A via a qualification 2874 // conversion (4.4). 2875 if (ArgType->isPointerType() || ArgType->isMemberPointerType() || 2876 ArgType->isObjCObjectPointerType()) 2877 TDF |= TDF_IgnoreQualifiers; 2878 // - If P is a class and P has the form simple-template-id, then the 2879 // transformed A can be a derived class of the deduced A. Likewise, 2880 // if P is a pointer to a class of the form simple-template-id, the 2881 // transformed A can be a pointer to a derived class pointed to by 2882 // the deduced A. 2883 if (isSimpleTemplateIdType(ParamType) || 2884 (isa<PointerType>(ParamType) && 2885 isSimpleTemplateIdType( 2886 ParamType->getAs<PointerType>()->getPointeeType()))) 2887 TDF |= TDF_DerivedClass; 2888 2889 return false; 2890} 2891 2892static bool hasDeducibleTemplateParameters(Sema &S, 2893 FunctionTemplateDecl *FunctionTemplate, 2894 QualType T); 2895 2896/// \brief Perform template argument deduction from a function call 2897/// (C++ [temp.deduct.call]). 2898/// 2899/// \param FunctionTemplate the function template for which we are performing 2900/// template argument deduction. 2901/// 2902/// \param ExplicitTemplateArguments the explicit template arguments provided 2903/// for this call. 2904/// 2905/// \param Args the function call arguments 2906/// 2907/// \param NumArgs the number of arguments in Args 2908/// 2909/// \param Name the name of the function being called. This is only significant 2910/// when the function template is a conversion function template, in which 2911/// case this routine will also perform template argument deduction based on 2912/// the function to which 2913/// 2914/// \param Specialization if template argument deduction was successful, 2915/// this will be set to the function template specialization produced by 2916/// template argument deduction. 2917/// 2918/// \param Info the argument will be updated to provide additional information 2919/// about template argument deduction. 2920/// 2921/// \returns the result of template argument deduction. 2922Sema::TemplateDeductionResult 2923Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 2924 TemplateArgumentListInfo *ExplicitTemplateArgs, 2925 llvm::ArrayRef<Expr *> Args, 2926 FunctionDecl *&Specialization, 2927 TemplateDeductionInfo &Info) { 2928 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2929 2930 // C++ [temp.deduct.call]p1: 2931 // Template argument deduction is done by comparing each function template 2932 // parameter type (call it P) with the type of the corresponding argument 2933 // of the call (call it A) as described below. 2934 unsigned CheckArgs = Args.size(); 2935 if (Args.size() < Function->getMinRequiredArguments()) 2936 return TDK_TooFewArguments; 2937 else if (Args.size() > Function->getNumParams()) { 2938 const FunctionProtoType *Proto 2939 = Function->getType()->getAs<FunctionProtoType>(); 2940 if (Proto->isTemplateVariadic()) 2941 /* Do nothing */; 2942 else if (Proto->isVariadic()) 2943 CheckArgs = Function->getNumParams(); 2944 else 2945 return TDK_TooManyArguments; 2946 } 2947 2948 // The types of the parameters from which we will perform template argument 2949 // deduction. 2950 LocalInstantiationScope InstScope(*this); 2951 TemplateParameterList *TemplateParams 2952 = FunctionTemplate->getTemplateParameters(); 2953 SmallVector<DeducedTemplateArgument, 4> Deduced; 2954 SmallVector<QualType, 4> ParamTypes; 2955 unsigned NumExplicitlySpecified = 0; 2956 if (ExplicitTemplateArgs) { 2957 TemplateDeductionResult Result = 2958 SubstituteExplicitTemplateArguments(FunctionTemplate, 2959 *ExplicitTemplateArgs, 2960 Deduced, 2961 ParamTypes, 2962 0, 2963 Info); 2964 if (Result) 2965 return Result; 2966 2967 NumExplicitlySpecified = Deduced.size(); 2968 } else { 2969 // Just fill in the parameter types from the function declaration. 2970 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 2971 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 2972 } 2973 2974 // Deduce template arguments from the function parameters. 2975 Deduced.resize(TemplateParams->size()); 2976 unsigned ArgIdx = 0; 2977 SmallVector<OriginalCallArg, 4> OriginalCallArgs; 2978 for (unsigned ParamIdx = 0, NumParams = ParamTypes.size(); 2979 ParamIdx != NumParams; ++ParamIdx) { 2980 QualType OrigParamType = ParamTypes[ParamIdx]; 2981 QualType ParamType = OrigParamType; 2982 2983 const PackExpansionType *ParamExpansion 2984 = dyn_cast<PackExpansionType>(ParamType); 2985 if (!ParamExpansion) { 2986 // Simple case: matching a function parameter to a function argument. 2987 if (ArgIdx >= CheckArgs) 2988 break; 2989 2990 Expr *Arg = Args[ArgIdx++]; 2991 QualType ArgType = Arg->getType(); 2992 2993 unsigned TDF = 0; 2994 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams, 2995 ParamType, ArgType, Arg, 2996 TDF)) 2997 continue; 2998 2999 // If we have nothing to deduce, we're done. 3000 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 3001 continue; 3002 3003 // If the argument is an initializer list ... 3004 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 3005 // ... then the parameter is an undeduced context, unless the parameter 3006 // type is (reference to cv) std::initializer_list<P'>, in which case 3007 // deduction is done for each element of the initializer list, and the 3008 // result is the deduced type if it's the same for all elements. 3009 QualType X; 3010 // Removing references was already done. 3011 if (!isStdInitializerList(ParamType, &X)) 3012 continue; 3013 3014 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 3015 if (TemplateDeductionResult Result = 3016 DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, X, 3017 ILE->getInit(i)->getType(), 3018 Info, Deduced, TDF)) 3019 return Result; 3020 } 3021 // Don't track the argument type, since an initializer list has none. 3022 continue; 3023 } 3024 3025 // Keep track of the argument type and corresponding parameter index, 3026 // so we can check for compatibility between the deduced A and A. 3027 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx-1, 3028 ArgType)); 3029 3030 if (TemplateDeductionResult Result 3031 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3032 ParamType, ArgType, 3033 Info, Deduced, TDF)) 3034 return Result; 3035 3036 continue; 3037 } 3038 3039 // C++0x [temp.deduct.call]p1: 3040 // For a function parameter pack that occurs at the end of the 3041 // parameter-declaration-list, the type A of each remaining argument of 3042 // the call is compared with the type P of the declarator-id of the 3043 // function parameter pack. Each comparison deduces template arguments 3044 // for subsequent positions in the template parameter packs expanded by 3045 // the function parameter pack. For a function parameter pack that does 3046 // not occur at the end of the parameter-declaration-list, the type of 3047 // the parameter pack is a non-deduced context. 3048 if (ParamIdx + 1 < NumParams) 3049 break; 3050 3051 QualType ParamPattern = ParamExpansion->getPattern(); 3052 SmallVector<unsigned, 2> PackIndices; 3053 { 3054 llvm::SmallBitVector SawIndices(TemplateParams->size()); 3055 SmallVector<UnexpandedParameterPack, 2> Unexpanded; 3056 collectUnexpandedParameterPacks(ParamPattern, Unexpanded); 3057 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { 3058 unsigned Depth, Index; 3059 llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); 3060 if (Depth == 0 && !SawIndices[Index]) { 3061 SawIndices[Index] = true; 3062 PackIndices.push_back(Index); 3063 } 3064 } 3065 } 3066 assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); 3067 3068 // Keep track of the deduced template arguments for each parameter pack 3069 // expanded by this pack expansion (the outer index) and for each 3070 // template argument (the inner SmallVectors). 3071 SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2> 3072 NewlyDeducedPacks(PackIndices.size()); 3073 SmallVector<DeducedTemplateArgument, 2> 3074 SavedPacks(PackIndices.size()); 3075 PrepareArgumentPackDeduction(*this, Deduced, PackIndices, SavedPacks, 3076 NewlyDeducedPacks); 3077 bool HasAnyArguments = false; 3078 for (; ArgIdx < Args.size(); ++ArgIdx) { 3079 HasAnyArguments = true; 3080 3081 QualType OrigParamType = ParamPattern; 3082 ParamType = OrigParamType; 3083 Expr *Arg = Args[ArgIdx]; 3084 QualType ArgType = Arg->getType(); 3085 3086 unsigned TDF = 0; 3087 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams, 3088 ParamType, ArgType, Arg, 3089 TDF)) { 3090 // We can't actually perform any deduction for this argument, so stop 3091 // deduction at this point. 3092 ++ArgIdx; 3093 break; 3094 } 3095 3096 // As above, initializer lists need special handling. 3097 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 3098 QualType X; 3099 if (!isStdInitializerList(ParamType, &X)) { 3100 ++ArgIdx; 3101 break; 3102 } 3103 3104 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 3105 if (TemplateDeductionResult Result = 3106 DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, X, 3107 ILE->getInit(i)->getType(), 3108 Info, Deduced, TDF)) 3109 return Result; 3110 } 3111 } else { 3112 3113 // Keep track of the argument type and corresponding argument index, 3114 // so we can check for compatibility between the deduced A and A. 3115 if (hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 3116 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx, 3117 ArgType)); 3118 3119 if (TemplateDeductionResult Result 3120 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3121 ParamType, ArgType, Info, 3122 Deduced, TDF)) 3123 return Result; 3124 } 3125 3126 // Capture the deduced template arguments for each parameter pack expanded 3127 // by this pack expansion, add them to the list of arguments we've deduced 3128 // for that pack, then clear out the deduced argument. 3129 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 3130 DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; 3131 if (!DeducedArg.isNull()) { 3132 NewlyDeducedPacks[I].push_back(DeducedArg); 3133 DeducedArg = DeducedTemplateArgument(); 3134 } 3135 } 3136 } 3137 3138 // Build argument packs for each of the parameter packs expanded by this 3139 // pack expansion. 3140 if (Sema::TemplateDeductionResult Result 3141 = FinishArgumentPackDeduction(*this, TemplateParams, HasAnyArguments, 3142 Deduced, PackIndices, SavedPacks, 3143 NewlyDeducedPacks, Info)) 3144 return Result; 3145 3146 // After we've matching against a parameter pack, we're done. 3147 break; 3148 } 3149 3150 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 3151 NumExplicitlySpecified, 3152 Specialization, Info, &OriginalCallArgs); 3153} 3154 3155/// \brief Deduce template arguments when taking the address of a function 3156/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 3157/// a template. 3158/// 3159/// \param FunctionTemplate the function template for which we are performing 3160/// template argument deduction. 3161/// 3162/// \param ExplicitTemplateArguments the explicitly-specified template 3163/// arguments. 3164/// 3165/// \param ArgFunctionType the function type that will be used as the 3166/// "argument" type (A) when performing template argument deduction from the 3167/// function template's function type. This type may be NULL, if there is no 3168/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 3169/// 3170/// \param Specialization if template argument deduction was successful, 3171/// this will be set to the function template specialization produced by 3172/// template argument deduction. 3173/// 3174/// \param Info the argument will be updated to provide additional information 3175/// about template argument deduction. 3176/// 3177/// \returns the result of template argument deduction. 3178Sema::TemplateDeductionResult 3179Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3180 TemplateArgumentListInfo *ExplicitTemplateArgs, 3181 QualType ArgFunctionType, 3182 FunctionDecl *&Specialization, 3183 TemplateDeductionInfo &Info) { 3184 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 3185 TemplateParameterList *TemplateParams 3186 = FunctionTemplate->getTemplateParameters(); 3187 QualType FunctionType = Function->getType(); 3188 3189 // Substitute any explicit template arguments. 3190 LocalInstantiationScope InstScope(*this); 3191 SmallVector<DeducedTemplateArgument, 4> Deduced; 3192 unsigned NumExplicitlySpecified = 0; 3193 SmallVector<QualType, 4> ParamTypes; 3194 if (ExplicitTemplateArgs) { 3195 if (TemplateDeductionResult Result 3196 = SubstituteExplicitTemplateArguments(FunctionTemplate, 3197 *ExplicitTemplateArgs, 3198 Deduced, ParamTypes, 3199 &FunctionType, Info)) 3200 return Result; 3201 3202 NumExplicitlySpecified = Deduced.size(); 3203 } 3204 3205 // Unevaluated SFINAE context. 3206 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 3207 SFINAETrap Trap(*this); 3208 3209 Deduced.resize(TemplateParams->size()); 3210 3211 if (!ArgFunctionType.isNull()) { 3212 // Deduce template arguments from the function type. 3213 if (TemplateDeductionResult Result 3214 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3215 FunctionType, ArgFunctionType, Info, 3216 Deduced, TDF_TopLevelParameterTypeList)) 3217 return Result; 3218 } 3219 3220 if (TemplateDeductionResult Result 3221 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 3222 NumExplicitlySpecified, 3223 Specialization, Info)) 3224 return Result; 3225 3226 // If the requested function type does not match the actual type of the 3227 // specialization, template argument deduction fails. 3228 if (!ArgFunctionType.isNull() && 3229 !Context.hasSameType(ArgFunctionType, Specialization->getType())) 3230 return TDK_NonDeducedMismatch; 3231 3232 return TDK_Success; 3233} 3234 3235/// \brief Deduce template arguments for a templated conversion 3236/// function (C++ [temp.deduct.conv]) and, if successful, produce a 3237/// conversion function template specialization. 3238Sema::TemplateDeductionResult 3239Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3240 QualType ToType, 3241 CXXConversionDecl *&Specialization, 3242 TemplateDeductionInfo &Info) { 3243 CXXConversionDecl *Conv 3244 = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()); 3245 QualType FromType = Conv->getConversionType(); 3246 3247 // Canonicalize the types for deduction. 3248 QualType P = Context.getCanonicalType(FromType); 3249 QualType A = Context.getCanonicalType(ToType); 3250 3251 // C++0x [temp.deduct.conv]p2: 3252 // If P is a reference type, the type referred to by P is used for 3253 // type deduction. 3254 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 3255 P = PRef->getPointeeType(); 3256 3257 // C++0x [temp.deduct.conv]p4: 3258 // [...] If A is a reference type, the type referred to by A is used 3259 // for type deduction. 3260 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 3261 A = ARef->getPointeeType().getUnqualifiedType(); 3262 // C++ [temp.deduct.conv]p3: 3263 // 3264 // If A is not a reference type: 3265 else { 3266 assert(!A->isReferenceType() && "Reference types were handled above"); 3267 3268 // - If P is an array type, the pointer type produced by the 3269 // array-to-pointer standard conversion (4.2) is used in place 3270 // of P for type deduction; otherwise, 3271 if (P->isArrayType()) 3272 P = Context.getArrayDecayedType(P); 3273 // - If P is a function type, the pointer type produced by the 3274 // function-to-pointer standard conversion (4.3) is used in 3275 // place of P for type deduction; otherwise, 3276 else if (P->isFunctionType()) 3277 P = Context.getPointerType(P); 3278 // - If P is a cv-qualified type, the top level cv-qualifiers of 3279 // P's type are ignored for type deduction. 3280 else 3281 P = P.getUnqualifiedType(); 3282 3283 // C++0x [temp.deduct.conv]p4: 3284 // If A is a cv-qualified type, the top level cv-qualifiers of A's 3285 // type are ignored for type deduction. If A is a reference type, the type 3286 // referred to by A is used for type deduction. 3287 A = A.getUnqualifiedType(); 3288 } 3289 3290 // Unevaluated SFINAE context. 3291 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 3292 SFINAETrap Trap(*this); 3293 3294 // C++ [temp.deduct.conv]p1: 3295 // Template argument deduction is done by comparing the return 3296 // type of the template conversion function (call it P) with the 3297 // type that is required as the result of the conversion (call it 3298 // A) as described in 14.8.2.4. 3299 TemplateParameterList *TemplateParams 3300 = FunctionTemplate->getTemplateParameters(); 3301 SmallVector<DeducedTemplateArgument, 4> Deduced; 3302 Deduced.resize(TemplateParams->size()); 3303 3304 // C++0x [temp.deduct.conv]p4: 3305 // In general, the deduction process attempts to find template 3306 // argument values that will make the deduced A identical to 3307 // A. However, there are two cases that allow a difference: 3308 unsigned TDF = 0; 3309 // - If the original A is a reference type, A can be more 3310 // cv-qualified than the deduced A (i.e., the type referred to 3311 // by the reference) 3312 if (ToType->isReferenceType()) 3313 TDF |= TDF_ParamWithReferenceType; 3314 // - The deduced A can be another pointer or pointer to member 3315 // type that can be converted to A via a qualification 3316 // conversion. 3317 // 3318 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 3319 // both P and A are pointers or member pointers. In this case, we 3320 // just ignore cv-qualifiers completely). 3321 if ((P->isPointerType() && A->isPointerType()) || 3322 (P->isMemberPointerType() && A->isMemberPointerType())) 3323 TDF |= TDF_IgnoreQualifiers; 3324 if (TemplateDeductionResult Result 3325 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3326 P, A, Info, Deduced, TDF)) 3327 return Result; 3328 3329 // Finish template argument deduction. 3330 LocalInstantiationScope InstScope(*this); 3331 FunctionDecl *Spec = 0; 3332 TemplateDeductionResult Result 3333 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, 3334 Info); 3335 Specialization = cast_or_null<CXXConversionDecl>(Spec); 3336 return Result; 3337} 3338 3339/// \brief Deduce template arguments for a function template when there is 3340/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 3341/// 3342/// \param FunctionTemplate the function template for which we are performing 3343/// template argument deduction. 3344/// 3345/// \param ExplicitTemplateArguments the explicitly-specified template 3346/// arguments. 3347/// 3348/// \param Specialization if template argument deduction was successful, 3349/// this will be set to the function template specialization produced by 3350/// template argument deduction. 3351/// 3352/// \param Info the argument will be updated to provide additional information 3353/// about template argument deduction. 3354/// 3355/// \returns the result of template argument deduction. 3356Sema::TemplateDeductionResult 3357Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3358 TemplateArgumentListInfo *ExplicitTemplateArgs, 3359 FunctionDecl *&Specialization, 3360 TemplateDeductionInfo &Info) { 3361 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3362 QualType(), Specialization, Info); 3363} 3364 3365namespace { 3366 /// Substitute the 'auto' type specifier within a type for a given replacement 3367 /// type. 3368 class SubstituteAutoTransform : 3369 public TreeTransform<SubstituteAutoTransform> { 3370 QualType Replacement; 3371 public: 3372 SubstituteAutoTransform(Sema &SemaRef, QualType Replacement) : 3373 TreeTransform<SubstituteAutoTransform>(SemaRef), Replacement(Replacement) { 3374 } 3375 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) { 3376 // If we're building the type pattern to deduce against, don't wrap the 3377 // substituted type in an AutoType. Certain template deduction rules 3378 // apply only when a template type parameter appears directly (and not if 3379 // the parameter is found through desugaring). For instance: 3380 // auto &&lref = lvalue; 3381 // must transform into "rvalue reference to T" not "rvalue reference to 3382 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply. 3383 if (isa<TemplateTypeParmType>(Replacement)) { 3384 QualType Result = Replacement; 3385 TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result); 3386 NewTL.setNameLoc(TL.getNameLoc()); 3387 return Result; 3388 } else { 3389 QualType Result = RebuildAutoType(Replacement); 3390 AutoTypeLoc NewTL = TLB.push<AutoTypeLoc>(Result); 3391 NewTL.setNameLoc(TL.getNameLoc()); 3392 return Result; 3393 } 3394 } 3395 3396 ExprResult TransformLambdaExpr(LambdaExpr *E) { 3397 // Lambdas never need to be transformed. 3398 return E; 3399 } 3400 }; 3401} 3402 3403/// \brief Deduce the type for an auto type-specifier (C++0x [dcl.spec.auto]p6) 3404/// 3405/// \param Type the type pattern using the auto type-specifier. 3406/// 3407/// \param Init the initializer for the variable whose type is to be deduced. 3408/// 3409/// \param Result if type deduction was successful, this will be set to the 3410/// deduced type. This may still contain undeduced autos if the type is 3411/// dependent. This will be set to null if deduction succeeded, but auto 3412/// substitution failed; the appropriate diagnostic will already have been 3413/// produced in that case. 3414Sema::DeduceAutoResult 3415Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, 3416 TypeSourceInfo *&Result) { 3417 if (Init->getType()->isNonOverloadPlaceholderType()) { 3418 ExprResult result = CheckPlaceholderExpr(Init); 3419 if (result.isInvalid()) return DAR_FailedAlreadyDiagnosed; 3420 Init = result.take(); 3421 } 3422 3423 if (Init->isTypeDependent()) { 3424 Result = Type; 3425 return DAR_Succeeded; 3426 } 3427 3428 SourceLocation Loc = Init->getExprLoc(); 3429 3430 LocalInstantiationScope InstScope(*this); 3431 3432 // Build template<class TemplParam> void Func(FuncParam); 3433 TemplateTypeParmDecl *TemplParam = 3434 TemplateTypeParmDecl::Create(Context, 0, SourceLocation(), Loc, 0, 0, 0, 3435 false, false); 3436 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0); 3437 NamedDecl *TemplParamPtr = TemplParam; 3438 FixedSizeTemplateParameterList<1> TemplateParams(Loc, Loc, &TemplParamPtr, 3439 Loc); 3440 3441 TypeSourceInfo *FuncParamInfo = 3442 SubstituteAutoTransform(*this, TemplArg).TransformType(Type); 3443 assert(FuncParamInfo && "substituting template parameter for 'auto' failed"); 3444 QualType FuncParam = FuncParamInfo->getType(); 3445 3446 // Deduce type of TemplParam in Func(Init) 3447 SmallVector<DeducedTemplateArgument, 1> Deduced; 3448 Deduced.resize(1); 3449 QualType InitType = Init->getType(); 3450 unsigned TDF = 0; 3451 if (AdjustFunctionParmAndArgTypesForDeduction(*this, &TemplateParams, 3452 FuncParam, InitType, Init, 3453 TDF)) 3454 return DAR_Failed; 3455 3456 TemplateDeductionInfo Info(Context, Loc); 3457 3458 InitListExpr * InitList = dyn_cast<InitListExpr>(Init); 3459 if (InitList) { 3460 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) { 3461 if (DeduceTemplateArgumentsByTypeMatch(*this, &TemplateParams, FuncParam, 3462 InitList->getInit(i)->getType(), 3463 Info, Deduced, TDF)) 3464 return DAR_Failed; 3465 } 3466 } else { 3467 if (DeduceTemplateArgumentsByTypeMatch(*this, &TemplateParams, FuncParam, 3468 InitType, Info, Deduced, TDF)) 3469 return DAR_Failed; 3470 } 3471 3472 QualType DeducedType = Deduced[0].getAsType(); 3473 if (DeducedType.isNull()) 3474 return DAR_Failed; 3475 3476 if (InitList) { 3477 DeducedType = BuildStdInitializerList(DeducedType, Loc); 3478 if (DeducedType.isNull()) 3479 return DAR_FailedAlreadyDiagnosed; 3480 } 3481 3482 Result = SubstituteAutoTransform(*this, DeducedType).TransformType(Type); 3483 3484 // Check that the deduced argument type is compatible with the original 3485 // argument type per C++ [temp.deduct.call]p4. 3486 if (!InitList && Result && 3487 CheckOriginalCallArgDeduction(*this, 3488 Sema::OriginalCallArg(FuncParam,0,InitType), 3489 Result->getType())) { 3490 Result = 0; 3491 return DAR_Failed; 3492 } 3493 3494 return DAR_Succeeded; 3495} 3496 3497void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) { 3498 if (isa<InitListExpr>(Init)) 3499 Diag(VDecl->getLocation(), 3500 diag::err_auto_var_deduction_failure_from_init_list) 3501 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange(); 3502 else 3503 Diag(VDecl->getLocation(), diag::err_auto_var_deduction_failure) 3504 << VDecl->getDeclName() << VDecl->getType() << Init->getType() 3505 << Init->getSourceRange(); 3506} 3507 3508static void 3509MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 3510 bool OnlyDeduced, 3511 unsigned Level, 3512 llvm::SmallBitVector &Deduced); 3513 3514/// \brief If this is a non-static member function, 3515static void MaybeAddImplicitObjectParameterType(ASTContext &Context, 3516 CXXMethodDecl *Method, 3517 SmallVectorImpl<QualType> &ArgTypes) { 3518 if (Method->isStatic()) 3519 return; 3520 3521 // C++ [over.match.funcs]p4: 3522 // 3523 // For non-static member functions, the type of the implicit 3524 // object parameter is 3525 // - "lvalue reference to cv X" for functions declared without a 3526 // ref-qualifier or with the & ref-qualifier 3527 // - "rvalue reference to cv X" for functions declared with the 3528 // && ref-qualifier 3529 // 3530 // FIXME: We don't have ref-qualifiers yet, so we don't do that part. 3531 QualType ArgTy = Context.getTypeDeclType(Method->getParent()); 3532 ArgTy = Context.getQualifiedType(ArgTy, 3533 Qualifiers::fromCVRMask(Method->getTypeQualifiers())); 3534 ArgTy = Context.getLValueReferenceType(ArgTy); 3535 ArgTypes.push_back(ArgTy); 3536} 3537 3538/// \brief Determine whether the function template \p FT1 is at least as 3539/// specialized as \p FT2. 3540static bool isAtLeastAsSpecializedAs(Sema &S, 3541 SourceLocation Loc, 3542 FunctionTemplateDecl *FT1, 3543 FunctionTemplateDecl *FT2, 3544 TemplatePartialOrderingContext TPOC, 3545 unsigned NumCallArguments, 3546 SmallVectorImpl<RefParamPartialOrderingComparison> *RefParamComparisons) { 3547 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 3548 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 3549 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 3550 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 3551 3552 assert(Proto1 && Proto2 && "Function templates must have prototypes"); 3553 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 3554 SmallVector<DeducedTemplateArgument, 4> Deduced; 3555 Deduced.resize(TemplateParams->size()); 3556 3557 // C++0x [temp.deduct.partial]p3: 3558 // The types used to determine the ordering depend on the context in which 3559 // the partial ordering is done: 3560 TemplateDeductionInfo Info(S.Context, Loc); 3561 CXXMethodDecl *Method1 = 0; 3562 CXXMethodDecl *Method2 = 0; 3563 bool IsNonStatic2 = false; 3564 bool IsNonStatic1 = false; 3565 unsigned Skip2 = 0; 3566 switch (TPOC) { 3567 case TPOC_Call: { 3568 // - In the context of a function call, the function parameter types are 3569 // used. 3570 Method1 = dyn_cast<CXXMethodDecl>(FD1); 3571 Method2 = dyn_cast<CXXMethodDecl>(FD2); 3572 IsNonStatic1 = Method1 && !Method1->isStatic(); 3573 IsNonStatic2 = Method2 && !Method2->isStatic(); 3574 3575 // C++0x [temp.func.order]p3: 3576 // [...] If only one of the function templates is a non-static 3577 // member, that function template is considered to have a new 3578 // first parameter inserted in its function parameter list. The 3579 // new parameter is of type "reference to cv A," where cv are 3580 // the cv-qualifiers of the function template (if any) and A is 3581 // the class of which the function template is a member. 3582 // 3583 // C++98/03 doesn't have this provision, so instead we drop the 3584 // first argument of the free function or static member, which 3585 // seems to match existing practice. 3586 SmallVector<QualType, 4> Args1; 3587 unsigned Skip1 = !S.getLangOptions().CPlusPlus0x && 3588 IsNonStatic2 && !IsNonStatic1; 3589 if (S.getLangOptions().CPlusPlus0x && IsNonStatic1 && !IsNonStatic2) 3590 MaybeAddImplicitObjectParameterType(S.Context, Method1, Args1); 3591 Args1.insert(Args1.end(), 3592 Proto1->arg_type_begin() + Skip1, Proto1->arg_type_end()); 3593 3594 SmallVector<QualType, 4> Args2; 3595 Skip2 = !S.getLangOptions().CPlusPlus0x && 3596 IsNonStatic1 && !IsNonStatic2; 3597 if (S.getLangOptions().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) 3598 MaybeAddImplicitObjectParameterType(S.Context, Method2, Args2); 3599 Args2.insert(Args2.end(), 3600 Proto2->arg_type_begin() + Skip2, Proto2->arg_type_end()); 3601 3602 // C++ [temp.func.order]p5: 3603 // The presence of unused ellipsis and default arguments has no effect on 3604 // the partial ordering of function templates. 3605 if (Args1.size() > NumCallArguments) 3606 Args1.resize(NumCallArguments); 3607 if (Args2.size() > NumCallArguments) 3608 Args2.resize(NumCallArguments); 3609 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(), 3610 Args1.data(), Args1.size(), Info, Deduced, 3611 TDF_None, /*PartialOrdering=*/true, 3612 RefParamComparisons)) 3613 return false; 3614 3615 break; 3616 } 3617 3618 case TPOC_Conversion: 3619 // - In the context of a call to a conversion operator, the return types 3620 // of the conversion function templates are used. 3621 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 3622 Proto2->getResultType(), 3623 Proto1->getResultType(), 3624 Info, Deduced, TDF_None, 3625 /*PartialOrdering=*/true, 3626 RefParamComparisons)) 3627 return false; 3628 break; 3629 3630 case TPOC_Other: 3631 // - In other contexts (14.6.6.2) the function template's function type 3632 // is used. 3633 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 3634 FD2->getType(), FD1->getType(), 3635 Info, Deduced, TDF_None, 3636 /*PartialOrdering=*/true, 3637 RefParamComparisons)) 3638 return false; 3639 break; 3640 } 3641 3642 // C++0x [temp.deduct.partial]p11: 3643 // In most cases, all template parameters must have values in order for 3644 // deduction to succeed, but for partial ordering purposes a template 3645 // parameter may remain without a value provided it is not used in the 3646 // types being used for partial ordering. [ Note: a template parameter used 3647 // in a non-deduced context is considered used. -end note] 3648 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 3649 for (; ArgIdx != NumArgs; ++ArgIdx) 3650 if (Deduced[ArgIdx].isNull()) 3651 break; 3652 3653 if (ArgIdx == NumArgs) { 3654 // All template arguments were deduced. FT1 is at least as specialized 3655 // as FT2. 3656 return true; 3657 } 3658 3659 // Figure out which template parameters were used. 3660 llvm::SmallBitVector UsedParameters(TemplateParams->size()); 3661 switch (TPOC) { 3662 case TPOC_Call: { 3663 unsigned NumParams = std::min(NumCallArguments, 3664 std::min(Proto1->getNumArgs(), 3665 Proto2->getNumArgs())); 3666 if (S.getLangOptions().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) 3667 ::MarkUsedTemplateParameters(S.Context, Method2->getThisType(S.Context), 3668 false, 3669 TemplateParams->getDepth(), UsedParameters); 3670 for (unsigned I = Skip2; I < NumParams; ++I) 3671 ::MarkUsedTemplateParameters(S.Context, Proto2->getArgType(I), false, 3672 TemplateParams->getDepth(), 3673 UsedParameters); 3674 break; 3675 } 3676 3677 case TPOC_Conversion: 3678 ::MarkUsedTemplateParameters(S.Context, Proto2->getResultType(), false, 3679 TemplateParams->getDepth(), 3680 UsedParameters); 3681 break; 3682 3683 case TPOC_Other: 3684 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false, 3685 TemplateParams->getDepth(), 3686 UsedParameters); 3687 break; 3688 } 3689 3690 for (; ArgIdx != NumArgs; ++ArgIdx) 3691 // If this argument had no value deduced but was used in one of the types 3692 // used for partial ordering, then deduction fails. 3693 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 3694 return false; 3695 3696 return true; 3697} 3698 3699/// \brief Determine whether this a function template whose parameter-type-list 3700/// ends with a function parameter pack. 3701static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) { 3702 FunctionDecl *Function = FunTmpl->getTemplatedDecl(); 3703 unsigned NumParams = Function->getNumParams(); 3704 if (NumParams == 0) 3705 return false; 3706 3707 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1); 3708 if (!Last->isParameterPack()) 3709 return false; 3710 3711 // Make sure that no previous parameter is a parameter pack. 3712 while (--NumParams > 0) { 3713 if (Function->getParamDecl(NumParams - 1)->isParameterPack()) 3714 return false; 3715 } 3716 3717 return true; 3718} 3719 3720/// \brief Returns the more specialized function template according 3721/// to the rules of function template partial ordering (C++ [temp.func.order]). 3722/// 3723/// \param FT1 the first function template 3724/// 3725/// \param FT2 the second function template 3726/// 3727/// \param TPOC the context in which we are performing partial ordering of 3728/// function templates. 3729/// 3730/// \param NumCallArguments The number of arguments in a call, used only 3731/// when \c TPOC is \c TPOC_Call. 3732/// 3733/// \returns the more specialized function template. If neither 3734/// template is more specialized, returns NULL. 3735FunctionTemplateDecl * 3736Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 3737 FunctionTemplateDecl *FT2, 3738 SourceLocation Loc, 3739 TemplatePartialOrderingContext TPOC, 3740 unsigned NumCallArguments) { 3741 SmallVector<RefParamPartialOrderingComparison, 4> RefParamComparisons; 3742 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 3743 NumCallArguments, 0); 3744 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 3745 NumCallArguments, 3746 &RefParamComparisons); 3747 3748 if (Better1 != Better2) // We have a clear winner 3749 return Better1? FT1 : FT2; 3750 3751 if (!Better1 && !Better2) // Neither is better than the other 3752 return 0; 3753 3754 // C++0x [temp.deduct.partial]p10: 3755 // If for each type being considered a given template is at least as 3756 // specialized for all types and more specialized for some set of types and 3757 // the other template is not more specialized for any types or is not at 3758 // least as specialized for any types, then the given template is more 3759 // specialized than the other template. Otherwise, neither template is more 3760 // specialized than the other. 3761 Better1 = false; 3762 Better2 = false; 3763 for (unsigned I = 0, N = RefParamComparisons.size(); I != N; ++I) { 3764 // C++0x [temp.deduct.partial]p9: 3765 // If, for a given type, deduction succeeds in both directions (i.e., the 3766 // types are identical after the transformations above) and both P and A 3767 // were reference types (before being replaced with the type referred to 3768 // above): 3769 3770 // -- if the type from the argument template was an lvalue reference 3771 // and the type from the parameter template was not, the argument 3772 // type is considered to be more specialized than the other; 3773 // otherwise, 3774 if (!RefParamComparisons[I].ArgIsRvalueRef && 3775 RefParamComparisons[I].ParamIsRvalueRef) { 3776 Better2 = true; 3777 if (Better1) 3778 return 0; 3779 continue; 3780 } else if (!RefParamComparisons[I].ParamIsRvalueRef && 3781 RefParamComparisons[I].ArgIsRvalueRef) { 3782 Better1 = true; 3783 if (Better2) 3784 return 0; 3785 continue; 3786 } 3787 3788 // -- if the type from the argument template is more cv-qualified than 3789 // the type from the parameter template (as described above), the 3790 // argument type is considered to be more specialized than the 3791 // other; otherwise, 3792 switch (RefParamComparisons[I].Qualifiers) { 3793 case NeitherMoreQualified: 3794 break; 3795 3796 case ParamMoreQualified: 3797 Better1 = true; 3798 if (Better2) 3799 return 0; 3800 continue; 3801 3802 case ArgMoreQualified: 3803 Better2 = true; 3804 if (Better1) 3805 return 0; 3806 continue; 3807 } 3808 3809 // -- neither type is more specialized than the other. 3810 } 3811 3812 assert(!(Better1 && Better2) && "Should have broken out in the loop above"); 3813 if (Better1) 3814 return FT1; 3815 else if (Better2) 3816 return FT2; 3817 3818 // FIXME: This mimics what GCC implements, but doesn't match up with the 3819 // proposed resolution for core issue 692. This area needs to be sorted out, 3820 // but for now we attempt to maintain compatibility. 3821 bool Variadic1 = isVariadicFunctionTemplate(FT1); 3822 bool Variadic2 = isVariadicFunctionTemplate(FT2); 3823 if (Variadic1 != Variadic2) 3824 return Variadic1? FT2 : FT1; 3825 3826 return 0; 3827} 3828 3829/// \brief Determine if the two templates are equivalent. 3830static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 3831 if (T1 == T2) 3832 return true; 3833 3834 if (!T1 || !T2) 3835 return false; 3836 3837 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 3838} 3839 3840/// \brief Retrieve the most specialized of the given function template 3841/// specializations. 3842/// 3843/// \param SpecBegin the start iterator of the function template 3844/// specializations that we will be comparing. 3845/// 3846/// \param SpecEnd the end iterator of the function template 3847/// specializations, paired with \p SpecBegin. 3848/// 3849/// \param TPOC the partial ordering context to use to compare the function 3850/// template specializations. 3851/// 3852/// \param NumCallArguments The number of arguments in a call, used only 3853/// when \c TPOC is \c TPOC_Call. 3854/// 3855/// \param Loc the location where the ambiguity or no-specializations 3856/// diagnostic should occur. 3857/// 3858/// \param NoneDiag partial diagnostic used to diagnose cases where there are 3859/// no matching candidates. 3860/// 3861/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 3862/// occurs. 3863/// 3864/// \param CandidateDiag partial diagnostic used for each function template 3865/// specialization that is a candidate in the ambiguous ordering. One parameter 3866/// in this diagnostic should be unbound, which will correspond to the string 3867/// describing the template arguments for the function template specialization. 3868/// 3869/// \param Index if non-NULL and the result of this function is non-nULL, 3870/// receives the index corresponding to the resulting function template 3871/// specialization. 3872/// 3873/// \returns the most specialized function template specialization, if 3874/// found. Otherwise, returns SpecEnd. 3875/// 3876/// \todo FIXME: Consider passing in the "also-ran" candidates that failed 3877/// template argument deduction. 3878UnresolvedSetIterator 3879Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, 3880 UnresolvedSetIterator SpecEnd, 3881 TemplatePartialOrderingContext TPOC, 3882 unsigned NumCallArguments, 3883 SourceLocation Loc, 3884 const PartialDiagnostic &NoneDiag, 3885 const PartialDiagnostic &AmbigDiag, 3886 const PartialDiagnostic &CandidateDiag, 3887 bool Complain, 3888 QualType TargetType) { 3889 if (SpecBegin == SpecEnd) { 3890 if (Complain) 3891 Diag(Loc, NoneDiag); 3892 return SpecEnd; 3893 } 3894 3895 if (SpecBegin + 1 == SpecEnd) 3896 return SpecBegin; 3897 3898 // Find the function template that is better than all of the templates it 3899 // has been compared to. 3900 UnresolvedSetIterator Best = SpecBegin; 3901 FunctionTemplateDecl *BestTemplate 3902 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 3903 assert(BestTemplate && "Not a function template specialization?"); 3904 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 3905 FunctionTemplateDecl *Challenger 3906 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 3907 assert(Challenger && "Not a function template specialization?"); 3908 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 3909 Loc, TPOC, NumCallArguments), 3910 Challenger)) { 3911 Best = I; 3912 BestTemplate = Challenger; 3913 } 3914 } 3915 3916 // Make sure that the "best" function template is more specialized than all 3917 // of the others. 3918 bool Ambiguous = false; 3919 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 3920 FunctionTemplateDecl *Challenger 3921 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 3922 if (I != Best && 3923 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 3924 Loc, TPOC, NumCallArguments), 3925 BestTemplate)) { 3926 Ambiguous = true; 3927 break; 3928 } 3929 } 3930 3931 if (!Ambiguous) { 3932 // We found an answer. Return it. 3933 return Best; 3934 } 3935 3936 // Diagnose the ambiguity. 3937 if (Complain) 3938 Diag(Loc, AmbigDiag); 3939 3940 if (Complain) 3941 // FIXME: Can we order the candidates in some sane way? 3942 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 3943 PartialDiagnostic PD = CandidateDiag; 3944 PD << getTemplateArgumentBindingsText( 3945 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(), 3946 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs()); 3947 if (!TargetType.isNull()) 3948 HandleFunctionTypeMismatch(PD, cast<FunctionDecl>(*I)->getType(), 3949 TargetType); 3950 Diag((*I)->getLocation(), PD); 3951 } 3952 3953 return SpecEnd; 3954} 3955 3956/// \brief Returns the more specialized class template partial specialization 3957/// according to the rules of partial ordering of class template partial 3958/// specializations (C++ [temp.class.order]). 3959/// 3960/// \param PS1 the first class template partial specialization 3961/// 3962/// \param PS2 the second class template partial specialization 3963/// 3964/// \returns the more specialized class template partial specialization. If 3965/// neither partial specialization is more specialized, returns NULL. 3966ClassTemplatePartialSpecializationDecl * 3967Sema::getMoreSpecializedPartialSpecialization( 3968 ClassTemplatePartialSpecializationDecl *PS1, 3969 ClassTemplatePartialSpecializationDecl *PS2, 3970 SourceLocation Loc) { 3971 // C++ [temp.class.order]p1: 3972 // For two class template partial specializations, the first is at least as 3973 // specialized as the second if, given the following rewrite to two 3974 // function templates, the first function template is at least as 3975 // specialized as the second according to the ordering rules for function 3976 // templates (14.6.6.2): 3977 // - the first function template has the same template parameters as the 3978 // first partial specialization and has a single function parameter 3979 // whose type is a class template specialization with the template 3980 // arguments of the first partial specialization, and 3981 // - the second function template has the same template parameters as the 3982 // second partial specialization and has a single function parameter 3983 // whose type is a class template specialization with the template 3984 // arguments of the second partial specialization. 3985 // 3986 // Rather than synthesize function templates, we merely perform the 3987 // equivalent partial ordering by performing deduction directly on 3988 // the template arguments of the class template partial 3989 // specializations. This computation is slightly simpler than the 3990 // general problem of function template partial ordering, because 3991 // class template partial specializations are more constrained. We 3992 // know that every template parameter is deducible from the class 3993 // template partial specialization's template arguments, for 3994 // example. 3995 SmallVector<DeducedTemplateArgument, 4> Deduced; 3996 TemplateDeductionInfo Info(Context, Loc); 3997 3998 QualType PT1 = PS1->getInjectedSpecializationType(); 3999 QualType PT2 = PS2->getInjectedSpecializationType(); 4000 4001 // Determine whether PS1 is at least as specialized as PS2 4002 Deduced.resize(PS2->getTemplateParameters()->size()); 4003 bool Better1 = !DeduceTemplateArgumentsByTypeMatch(*this, 4004 PS2->getTemplateParameters(), 4005 PT2, PT1, Info, Deduced, TDF_None, 4006 /*PartialOrdering=*/true, 4007 /*RefParamComparisons=*/0); 4008 if (Better1) { 4009 InstantiatingTemplate Inst(*this, PS2->getLocation(), PS2, 4010 Deduced.data(), Deduced.size(), Info); 4011 Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, 4012 PS1->getTemplateArgs(), 4013 Deduced, Info); 4014 } 4015 4016 // Determine whether PS2 is at least as specialized as PS1 4017 Deduced.clear(); 4018 Deduced.resize(PS1->getTemplateParameters()->size()); 4019 bool Better2 = !DeduceTemplateArgumentsByTypeMatch(*this, 4020 PS1->getTemplateParameters(), 4021 PT1, PT2, Info, Deduced, TDF_None, 4022 /*PartialOrdering=*/true, 4023 /*RefParamComparisons=*/0); 4024 if (Better2) { 4025 InstantiatingTemplate Inst(*this, PS1->getLocation(), PS1, 4026 Deduced.data(), Deduced.size(), Info); 4027 Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, 4028 PS2->getTemplateArgs(), 4029 Deduced, Info); 4030 } 4031 4032 if (Better1 == Better2) 4033 return 0; 4034 4035 return Better1? PS1 : PS2; 4036} 4037 4038static void 4039MarkUsedTemplateParameters(ASTContext &Ctx, 4040 const TemplateArgument &TemplateArg, 4041 bool OnlyDeduced, 4042 unsigned Depth, 4043 llvm::SmallBitVector &Used); 4044 4045/// \brief Mark the template parameters that are used by the given 4046/// expression. 4047static void 4048MarkUsedTemplateParameters(ASTContext &Ctx, 4049 const Expr *E, 4050 bool OnlyDeduced, 4051 unsigned Depth, 4052 llvm::SmallBitVector &Used) { 4053 // We can deduce from a pack expansion. 4054 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E)) 4055 E = Expansion->getPattern(); 4056 4057 // Skip through any implicit casts we added while type-checking. 4058 while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) 4059 E = ICE->getSubExpr(); 4060 4061 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to 4062 // find other occurrences of template parameters. 4063 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E); 4064 if (!DRE) 4065 return; 4066 4067 const NonTypeTemplateParmDecl *NTTP 4068 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 4069 if (!NTTP) 4070 return; 4071 4072 if (NTTP->getDepth() == Depth) 4073 Used[NTTP->getIndex()] = true; 4074} 4075 4076/// \brief Mark the template parameters that are used by the given 4077/// nested name specifier. 4078static void 4079MarkUsedTemplateParameters(ASTContext &Ctx, 4080 NestedNameSpecifier *NNS, 4081 bool OnlyDeduced, 4082 unsigned Depth, 4083 llvm::SmallBitVector &Used) { 4084 if (!NNS) 4085 return; 4086 4087 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth, 4088 Used); 4089 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0), 4090 OnlyDeduced, Depth, Used); 4091} 4092 4093/// \brief Mark the template parameters that are used by the given 4094/// template name. 4095static void 4096MarkUsedTemplateParameters(ASTContext &Ctx, 4097 TemplateName Name, 4098 bool OnlyDeduced, 4099 unsigned Depth, 4100 llvm::SmallBitVector &Used) { 4101 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 4102 if (TemplateTemplateParmDecl *TTP 4103 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 4104 if (TTP->getDepth() == Depth) 4105 Used[TTP->getIndex()] = true; 4106 } 4107 return; 4108 } 4109 4110 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 4111 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced, 4112 Depth, Used); 4113 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 4114 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced, 4115 Depth, Used); 4116} 4117 4118/// \brief Mark the template parameters that are used by the given 4119/// type. 4120static void 4121MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 4122 bool OnlyDeduced, 4123 unsigned Depth, 4124 llvm::SmallBitVector &Used) { 4125 if (T.isNull()) 4126 return; 4127 4128 // Non-dependent types have nothing deducible 4129 if (!T->isDependentType()) 4130 return; 4131 4132 T = Ctx.getCanonicalType(T); 4133 switch (T->getTypeClass()) { 4134 case Type::Pointer: 4135 MarkUsedTemplateParameters(Ctx, 4136 cast<PointerType>(T)->getPointeeType(), 4137 OnlyDeduced, 4138 Depth, 4139 Used); 4140 break; 4141 4142 case Type::BlockPointer: 4143 MarkUsedTemplateParameters(Ctx, 4144 cast<BlockPointerType>(T)->getPointeeType(), 4145 OnlyDeduced, 4146 Depth, 4147 Used); 4148 break; 4149 4150 case Type::LValueReference: 4151 case Type::RValueReference: 4152 MarkUsedTemplateParameters(Ctx, 4153 cast<ReferenceType>(T)->getPointeeType(), 4154 OnlyDeduced, 4155 Depth, 4156 Used); 4157 break; 4158 4159 case Type::MemberPointer: { 4160 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 4161 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced, 4162 Depth, Used); 4163 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0), 4164 OnlyDeduced, Depth, Used); 4165 break; 4166 } 4167 4168 case Type::DependentSizedArray: 4169 MarkUsedTemplateParameters(Ctx, 4170 cast<DependentSizedArrayType>(T)->getSizeExpr(), 4171 OnlyDeduced, Depth, Used); 4172 // Fall through to check the element type 4173 4174 case Type::ConstantArray: 4175 case Type::IncompleteArray: 4176 MarkUsedTemplateParameters(Ctx, 4177 cast<ArrayType>(T)->getElementType(), 4178 OnlyDeduced, Depth, Used); 4179 break; 4180 4181 case Type::Vector: 4182 case Type::ExtVector: 4183 MarkUsedTemplateParameters(Ctx, 4184 cast<VectorType>(T)->getElementType(), 4185 OnlyDeduced, Depth, Used); 4186 break; 4187 4188 case Type::DependentSizedExtVector: { 4189 const DependentSizedExtVectorType *VecType 4190 = cast<DependentSizedExtVectorType>(T); 4191 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced, 4192 Depth, Used); 4193 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, 4194 Depth, Used); 4195 break; 4196 } 4197 4198 case Type::FunctionProto: { 4199 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 4200 MarkUsedTemplateParameters(Ctx, Proto->getResultType(), OnlyDeduced, 4201 Depth, Used); 4202 for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) 4203 MarkUsedTemplateParameters(Ctx, Proto->getArgType(I), OnlyDeduced, 4204 Depth, Used); 4205 break; 4206 } 4207 4208 case Type::TemplateTypeParm: { 4209 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 4210 if (TTP->getDepth() == Depth) 4211 Used[TTP->getIndex()] = true; 4212 break; 4213 } 4214 4215 case Type::SubstTemplateTypeParmPack: { 4216 const SubstTemplateTypeParmPackType *Subst 4217 = cast<SubstTemplateTypeParmPackType>(T); 4218 MarkUsedTemplateParameters(Ctx, 4219 QualType(Subst->getReplacedParameter(), 0), 4220 OnlyDeduced, Depth, Used); 4221 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(), 4222 OnlyDeduced, Depth, Used); 4223 break; 4224 } 4225 4226 case Type::InjectedClassName: 4227 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 4228 // fall through 4229 4230 case Type::TemplateSpecialization: { 4231 const TemplateSpecializationType *Spec 4232 = cast<TemplateSpecializationType>(T); 4233 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced, 4234 Depth, Used); 4235 4236 // C++0x [temp.deduct.type]p9: 4237 // If the template argument list of P contains a pack expansion that is not 4238 // the last template argument, the entire template argument list is a 4239 // non-deduced context. 4240 if (OnlyDeduced && 4241 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) 4242 break; 4243 4244 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 4245 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 4246 Used); 4247 break; 4248 } 4249 4250 case Type::Complex: 4251 if (!OnlyDeduced) 4252 MarkUsedTemplateParameters(Ctx, 4253 cast<ComplexType>(T)->getElementType(), 4254 OnlyDeduced, Depth, Used); 4255 break; 4256 4257 case Type::Atomic: 4258 if (!OnlyDeduced) 4259 MarkUsedTemplateParameters(Ctx, 4260 cast<AtomicType>(T)->getValueType(), 4261 OnlyDeduced, Depth, Used); 4262 break; 4263 4264 case Type::DependentName: 4265 if (!OnlyDeduced) 4266 MarkUsedTemplateParameters(Ctx, 4267 cast<DependentNameType>(T)->getQualifier(), 4268 OnlyDeduced, Depth, Used); 4269 break; 4270 4271 case Type::DependentTemplateSpecialization: { 4272 const DependentTemplateSpecializationType *Spec 4273 = cast<DependentTemplateSpecializationType>(T); 4274 if (!OnlyDeduced) 4275 MarkUsedTemplateParameters(Ctx, Spec->getQualifier(), 4276 OnlyDeduced, Depth, Used); 4277 4278 // C++0x [temp.deduct.type]p9: 4279 // If the template argument list of P contains a pack expansion that is not 4280 // the last template argument, the entire template argument list is a 4281 // non-deduced context. 4282 if (OnlyDeduced && 4283 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) 4284 break; 4285 4286 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 4287 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 4288 Used); 4289 break; 4290 } 4291 4292 case Type::TypeOf: 4293 if (!OnlyDeduced) 4294 MarkUsedTemplateParameters(Ctx, 4295 cast<TypeOfType>(T)->getUnderlyingType(), 4296 OnlyDeduced, Depth, Used); 4297 break; 4298 4299 case Type::TypeOfExpr: 4300 if (!OnlyDeduced) 4301 MarkUsedTemplateParameters(Ctx, 4302 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 4303 OnlyDeduced, Depth, Used); 4304 break; 4305 4306 case Type::Decltype: 4307 if (!OnlyDeduced) 4308 MarkUsedTemplateParameters(Ctx, 4309 cast<DecltypeType>(T)->getUnderlyingExpr(), 4310 OnlyDeduced, Depth, Used); 4311 break; 4312 4313 case Type::UnaryTransform: 4314 if (!OnlyDeduced) 4315 MarkUsedTemplateParameters(Ctx, 4316 cast<UnaryTransformType>(T)->getUnderlyingType(), 4317 OnlyDeduced, Depth, Used); 4318 break; 4319 4320 case Type::PackExpansion: 4321 MarkUsedTemplateParameters(Ctx, 4322 cast<PackExpansionType>(T)->getPattern(), 4323 OnlyDeduced, Depth, Used); 4324 break; 4325 4326 case Type::Auto: 4327 MarkUsedTemplateParameters(Ctx, 4328 cast<AutoType>(T)->getDeducedType(), 4329 OnlyDeduced, Depth, Used); 4330 4331 // None of these types have any template parameters in them. 4332 case Type::Builtin: 4333 case Type::VariableArray: 4334 case Type::FunctionNoProto: 4335 case Type::Record: 4336 case Type::Enum: 4337 case Type::ObjCInterface: 4338 case Type::ObjCObject: 4339 case Type::ObjCObjectPointer: 4340 case Type::UnresolvedUsing: 4341#define TYPE(Class, Base) 4342#define ABSTRACT_TYPE(Class, Base) 4343#define DEPENDENT_TYPE(Class, Base) 4344#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 4345#include "clang/AST/TypeNodes.def" 4346 break; 4347 } 4348} 4349 4350/// \brief Mark the template parameters that are used by this 4351/// template argument. 4352static void 4353MarkUsedTemplateParameters(ASTContext &Ctx, 4354 const TemplateArgument &TemplateArg, 4355 bool OnlyDeduced, 4356 unsigned Depth, 4357 llvm::SmallBitVector &Used) { 4358 switch (TemplateArg.getKind()) { 4359 case TemplateArgument::Null: 4360 case TemplateArgument::Integral: 4361 case TemplateArgument::Declaration: 4362 break; 4363 4364 case TemplateArgument::Type: 4365 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced, 4366 Depth, Used); 4367 break; 4368 4369 case TemplateArgument::Template: 4370 case TemplateArgument::TemplateExpansion: 4371 MarkUsedTemplateParameters(Ctx, 4372 TemplateArg.getAsTemplateOrTemplatePattern(), 4373 OnlyDeduced, Depth, Used); 4374 break; 4375 4376 case TemplateArgument::Expression: 4377 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced, 4378 Depth, Used); 4379 break; 4380 4381 case TemplateArgument::Pack: 4382 for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), 4383 PEnd = TemplateArg.pack_end(); 4384 P != PEnd; ++P) 4385 MarkUsedTemplateParameters(Ctx, *P, OnlyDeduced, Depth, Used); 4386 break; 4387 } 4388} 4389 4390/// \brief Mark the template parameters can be deduced by the given 4391/// template argument list. 4392/// 4393/// \param TemplateArgs the template argument list from which template 4394/// parameters will be deduced. 4395/// 4396/// \param Deduced a bit vector whose elements will be set to \c true 4397/// to indicate when the corresponding template parameter will be 4398/// deduced. 4399void 4400Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 4401 bool OnlyDeduced, unsigned Depth, 4402 llvm::SmallBitVector &Used) { 4403 // C++0x [temp.deduct.type]p9: 4404 // If the template argument list of P contains a pack expansion that is not 4405 // the last template argument, the entire template argument list is a 4406 // non-deduced context. 4407 if (OnlyDeduced && 4408 hasPackExpansionBeforeEnd(TemplateArgs.data(), TemplateArgs.size())) 4409 return; 4410 4411 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 4412 ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced, 4413 Depth, Used); 4414} 4415 4416/// \brief Marks all of the template parameters that will be deduced by a 4417/// call to the given function template. 4418void 4419Sema::MarkDeducedTemplateParameters(ASTContext &Ctx, 4420 FunctionTemplateDecl *FunctionTemplate, 4421 llvm::SmallBitVector &Deduced) { 4422 TemplateParameterList *TemplateParams 4423 = FunctionTemplate->getTemplateParameters(); 4424 Deduced.clear(); 4425 Deduced.resize(TemplateParams->size()); 4426 4427 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 4428 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 4429 ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(), 4430 true, TemplateParams->getDepth(), Deduced); 4431} 4432 4433bool hasDeducibleTemplateParameters(Sema &S, 4434 FunctionTemplateDecl *FunctionTemplate, 4435 QualType T) { 4436 if (!T->isDependentType()) 4437 return false; 4438 4439 TemplateParameterList *TemplateParams 4440 = FunctionTemplate->getTemplateParameters(); 4441 llvm::SmallBitVector Deduced(TemplateParams->size()); 4442 ::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(), 4443 Deduced); 4444 4445 return Deduced.any(); 4446} 4447