SemaTemplateDeduction.cpp revision 4b911e6536ed77524c3cef572cb0f6c8d9079e2e
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.getLangOpts().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 // C++0x [temp.deduct.call]p6: 2713 // When P is a function type, pointer to function type, or pointer 2714 // to member function type: 2715 2716 if (!ParamType->isFunctionType() && 2717 !ParamType->isFunctionPointerType() && 2718 !ParamType->isMemberFunctionPointerType()) { 2719 if (Ovl->hasExplicitTemplateArgs()) { 2720 // But we can still look for an explicit specialization. 2721 if (FunctionDecl *ExplicitSpec 2722 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 2723 return GetTypeOfFunction(S.Context, R, ExplicitSpec); 2724 } 2725 2726 return QualType(); 2727 } 2728 2729 // Gather the explicit template arguments, if any. 2730 TemplateArgumentListInfo ExplicitTemplateArgs; 2731 if (Ovl->hasExplicitTemplateArgs()) 2732 Ovl->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 2733 QualType Match; 2734 for (UnresolvedSetIterator I = Ovl->decls_begin(), 2735 E = Ovl->decls_end(); I != E; ++I) { 2736 NamedDecl *D = (*I)->getUnderlyingDecl(); 2737 2738 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) { 2739 // - If the argument is an overload set containing one or more 2740 // function templates, the parameter is treated as a 2741 // non-deduced context. 2742 if (!Ovl->hasExplicitTemplateArgs()) 2743 return QualType(); 2744 2745 // Otherwise, see if we can resolve a function type 2746 FunctionDecl *Specialization = 0; 2747 TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 2748 if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs, 2749 Specialization, Info)) 2750 continue; 2751 2752 D = Specialization; 2753 } 2754 2755 FunctionDecl *Fn = cast<FunctionDecl>(D); 2756 QualType ArgType = GetTypeOfFunction(S.Context, R, Fn); 2757 if (ArgType.isNull()) continue; 2758 2759 // Function-to-pointer conversion. 2760 if (!ParamWasReference && ParamType->isPointerType() && 2761 ArgType->isFunctionType()) 2762 ArgType = S.Context.getPointerType(ArgType); 2763 2764 // - If the argument is an overload set (not containing function 2765 // templates), trial argument deduction is attempted using each 2766 // of the members of the set. If deduction succeeds for only one 2767 // of the overload set members, that member is used as the 2768 // argument value for the deduction. If deduction succeeds for 2769 // more than one member of the overload set the parameter is 2770 // treated as a non-deduced context. 2771 2772 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 2773 // Type deduction is done independently for each P/A pair, and 2774 // the deduced template argument values are then combined. 2775 // So we do not reject deductions which were made elsewhere. 2776 SmallVector<DeducedTemplateArgument, 8> 2777 Deduced(TemplateParams->size()); 2778 TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 2779 Sema::TemplateDeductionResult Result 2780 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 2781 ArgType, Info, Deduced, TDF); 2782 if (Result) continue; 2783 if (!Match.isNull()) return QualType(); 2784 Match = ArgType; 2785 } 2786 2787 return Match; 2788} 2789 2790/// \brief Perform the adjustments to the parameter and argument types 2791/// described in C++ [temp.deduct.call]. 2792/// 2793/// \returns true if the caller should not attempt to perform any template 2794/// argument deduction based on this P/A pair. 2795static bool AdjustFunctionParmAndArgTypesForDeduction(Sema &S, 2796 TemplateParameterList *TemplateParams, 2797 QualType &ParamType, 2798 QualType &ArgType, 2799 Expr *Arg, 2800 unsigned &TDF) { 2801 // C++0x [temp.deduct.call]p3: 2802 // If P is a cv-qualified type, the top level cv-qualifiers of P's type 2803 // are ignored for type deduction. 2804 if (ParamType.hasQualifiers()) 2805 ParamType = ParamType.getUnqualifiedType(); 2806 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>(); 2807 if (ParamRefType) { 2808 QualType PointeeType = ParamRefType->getPointeeType(); 2809 2810 // If the argument has incomplete array type, try to complete it's type. 2811 if (ArgType->isIncompleteArrayType() && 2812 !S.RequireCompleteExprType(Arg, S.PDiag(), 2813 std::make_pair(SourceLocation(), S.PDiag()))) 2814 ArgType = Arg->getType(); 2815 2816 // [C++0x] If P is an rvalue reference to a cv-unqualified 2817 // template parameter and the argument is an lvalue, the type 2818 // "lvalue reference to A" is used in place of A for type 2819 // deduction. 2820 if (isa<RValueReferenceType>(ParamType)) { 2821 if (!PointeeType.getQualifiers() && 2822 isa<TemplateTypeParmType>(PointeeType) && 2823 Arg->Classify(S.Context).isLValue() && 2824 Arg->getType() != S.Context.OverloadTy && 2825 Arg->getType() != S.Context.BoundMemberTy) 2826 ArgType = S.Context.getLValueReferenceType(ArgType); 2827 } 2828 2829 // [...] If P is a reference type, the type referred to by P is used 2830 // for type deduction. 2831 ParamType = PointeeType; 2832 } 2833 2834 // Overload sets usually make this parameter an undeduced 2835 // context, but there are sometimes special circumstances. 2836 if (ArgType == S.Context.OverloadTy) { 2837 ArgType = ResolveOverloadForDeduction(S, TemplateParams, 2838 Arg, ParamType, 2839 ParamRefType != 0); 2840 if (ArgType.isNull()) 2841 return true; 2842 } 2843 2844 if (ParamRefType) { 2845 // C++0x [temp.deduct.call]p3: 2846 // [...] If P is of the form T&&, where T is a template parameter, and 2847 // the argument is an lvalue, the type A& is used in place of A for 2848 // type deduction. 2849 if (ParamRefType->isRValueReferenceType() && 2850 ParamRefType->getAs<TemplateTypeParmType>() && 2851 Arg->isLValue()) 2852 ArgType = S.Context.getLValueReferenceType(ArgType); 2853 } else { 2854 // C++ [temp.deduct.call]p2: 2855 // If P is not a reference type: 2856 // - If A is an array type, the pointer type produced by the 2857 // array-to-pointer standard conversion (4.2) is used in place of 2858 // A for type deduction; otherwise, 2859 if (ArgType->isArrayType()) 2860 ArgType = S.Context.getArrayDecayedType(ArgType); 2861 // - If A is a function type, the pointer type produced by the 2862 // function-to-pointer standard conversion (4.3) is used in place 2863 // of A for type deduction; otherwise, 2864 else if (ArgType->isFunctionType()) 2865 ArgType = S.Context.getPointerType(ArgType); 2866 else { 2867 // - If A is a cv-qualified type, the top level cv-qualifiers of A's 2868 // type are ignored for type deduction. 2869 ArgType = ArgType.getUnqualifiedType(); 2870 } 2871 } 2872 2873 // C++0x [temp.deduct.call]p4: 2874 // In general, the deduction process attempts to find template argument 2875 // values that will make the deduced A identical to A (after the type A 2876 // is transformed as described above). [...] 2877 TDF = TDF_SkipNonDependent; 2878 2879 // - If the original P is a reference type, the deduced A (i.e., the 2880 // type referred to by the reference) can be more cv-qualified than 2881 // the transformed A. 2882 if (ParamRefType) 2883 TDF |= TDF_ParamWithReferenceType; 2884 // - The transformed A can be another pointer or pointer to member 2885 // type that can be converted to the deduced A via a qualification 2886 // conversion (4.4). 2887 if (ArgType->isPointerType() || ArgType->isMemberPointerType() || 2888 ArgType->isObjCObjectPointerType()) 2889 TDF |= TDF_IgnoreQualifiers; 2890 // - If P is a class and P has the form simple-template-id, then the 2891 // transformed A can be a derived class of the deduced A. Likewise, 2892 // if P is a pointer to a class of the form simple-template-id, the 2893 // transformed A can be a pointer to a derived class pointed to by 2894 // the deduced A. 2895 if (isSimpleTemplateIdType(ParamType) || 2896 (isa<PointerType>(ParamType) && 2897 isSimpleTemplateIdType( 2898 ParamType->getAs<PointerType>()->getPointeeType()))) 2899 TDF |= TDF_DerivedClass; 2900 2901 return false; 2902} 2903 2904static bool hasDeducibleTemplateParameters(Sema &S, 2905 FunctionTemplateDecl *FunctionTemplate, 2906 QualType T); 2907 2908/// \brief Perform template argument deduction by matching a parameter type 2909/// against a single expression, where the expression is an element of 2910/// an initializer list that was originally matched against the argument 2911/// type. 2912static Sema::TemplateDeductionResult 2913DeduceTemplateArgumentByListElement(Sema &S, 2914 TemplateParameterList *TemplateParams, 2915 QualType ParamType, Expr *Arg, 2916 TemplateDeductionInfo &Info, 2917 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2918 unsigned TDF) { 2919 // Handle the case where an init list contains another init list as the 2920 // element. 2921 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 2922 QualType X; 2923 if (!S.isStdInitializerList(ParamType.getNonReferenceType(), &X)) 2924 return Sema::TDK_Success; // Just ignore this expression. 2925 2926 // Recurse down into the init list. 2927 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 2928 if (Sema::TemplateDeductionResult Result = 2929 DeduceTemplateArgumentByListElement(S, TemplateParams, X, 2930 ILE->getInit(i), 2931 Info, Deduced, TDF)) 2932 return Result; 2933 } 2934 return Sema::TDK_Success; 2935 } 2936 2937 // For all other cases, just match by type. 2938 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 2939 Arg->getType(), Info, Deduced, TDF); 2940} 2941 2942/// \brief Perform template argument deduction from a function call 2943/// (C++ [temp.deduct.call]). 2944/// 2945/// \param FunctionTemplate the function template for which we are performing 2946/// template argument deduction. 2947/// 2948/// \param ExplicitTemplateArguments the explicit template arguments provided 2949/// for this call. 2950/// 2951/// \param Args the function call arguments 2952/// 2953/// \param NumArgs the number of arguments in Args 2954/// 2955/// \param Name the name of the function being called. This is only significant 2956/// when the function template is a conversion function template, in which 2957/// case this routine will also perform template argument deduction based on 2958/// the function to which 2959/// 2960/// \param Specialization if template argument deduction was successful, 2961/// this will be set to the function template specialization produced by 2962/// template argument deduction. 2963/// 2964/// \param Info the argument will be updated to provide additional information 2965/// about template argument deduction. 2966/// 2967/// \returns the result of template argument deduction. 2968Sema::TemplateDeductionResult 2969Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 2970 TemplateArgumentListInfo *ExplicitTemplateArgs, 2971 llvm::ArrayRef<Expr *> Args, 2972 FunctionDecl *&Specialization, 2973 TemplateDeductionInfo &Info) { 2974 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2975 2976 // C++ [temp.deduct.call]p1: 2977 // Template argument deduction is done by comparing each function template 2978 // parameter type (call it P) with the type of the corresponding argument 2979 // of the call (call it A) as described below. 2980 unsigned CheckArgs = Args.size(); 2981 if (Args.size() < Function->getMinRequiredArguments()) 2982 return TDK_TooFewArguments; 2983 else if (Args.size() > Function->getNumParams()) { 2984 const FunctionProtoType *Proto 2985 = Function->getType()->getAs<FunctionProtoType>(); 2986 if (Proto->isTemplateVariadic()) 2987 /* Do nothing */; 2988 else if (Proto->isVariadic()) 2989 CheckArgs = Function->getNumParams(); 2990 else 2991 return TDK_TooManyArguments; 2992 } 2993 2994 // The types of the parameters from which we will perform template argument 2995 // deduction. 2996 LocalInstantiationScope InstScope(*this); 2997 TemplateParameterList *TemplateParams 2998 = FunctionTemplate->getTemplateParameters(); 2999 SmallVector<DeducedTemplateArgument, 4> Deduced; 3000 SmallVector<QualType, 4> ParamTypes; 3001 unsigned NumExplicitlySpecified = 0; 3002 if (ExplicitTemplateArgs) { 3003 TemplateDeductionResult Result = 3004 SubstituteExplicitTemplateArguments(FunctionTemplate, 3005 *ExplicitTemplateArgs, 3006 Deduced, 3007 ParamTypes, 3008 0, 3009 Info); 3010 if (Result) 3011 return Result; 3012 3013 NumExplicitlySpecified = Deduced.size(); 3014 } else { 3015 // Just fill in the parameter types from the function declaration. 3016 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 3017 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 3018 } 3019 3020 // Deduce template arguments from the function parameters. 3021 Deduced.resize(TemplateParams->size()); 3022 unsigned ArgIdx = 0; 3023 SmallVector<OriginalCallArg, 4> OriginalCallArgs; 3024 for (unsigned ParamIdx = 0, NumParams = ParamTypes.size(); 3025 ParamIdx != NumParams; ++ParamIdx) { 3026 QualType OrigParamType = ParamTypes[ParamIdx]; 3027 QualType ParamType = OrigParamType; 3028 3029 const PackExpansionType *ParamExpansion 3030 = dyn_cast<PackExpansionType>(ParamType); 3031 if (!ParamExpansion) { 3032 // Simple case: matching a function parameter to a function argument. 3033 if (ArgIdx >= CheckArgs) 3034 break; 3035 3036 Expr *Arg = Args[ArgIdx++]; 3037 QualType ArgType = Arg->getType(); 3038 3039 unsigned TDF = 0; 3040 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams, 3041 ParamType, ArgType, Arg, 3042 TDF)) 3043 continue; 3044 3045 // If we have nothing to deduce, we're done. 3046 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 3047 continue; 3048 3049 // If the argument is an initializer list ... 3050 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 3051 // ... then the parameter is an undeduced context, unless the parameter 3052 // type is (reference to cv) std::initializer_list<P'>, in which case 3053 // deduction is done for each element of the initializer list, and the 3054 // result is the deduced type if it's the same for all elements. 3055 QualType X; 3056 // Removing references was already done. 3057 if (!isStdInitializerList(ParamType, &X)) 3058 continue; 3059 3060 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 3061 if (TemplateDeductionResult Result = 3062 DeduceTemplateArgumentByListElement(*this, TemplateParams, X, 3063 ILE->getInit(i), 3064 Info, Deduced, TDF)) 3065 return Result; 3066 } 3067 // Don't track the argument type, since an initializer list has none. 3068 continue; 3069 } 3070 3071 // Keep track of the argument type and corresponding parameter index, 3072 // so we can check for compatibility between the deduced A and A. 3073 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx-1, 3074 ArgType)); 3075 3076 if (TemplateDeductionResult Result 3077 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3078 ParamType, ArgType, 3079 Info, Deduced, TDF)) 3080 return Result; 3081 3082 continue; 3083 } 3084 3085 // C++0x [temp.deduct.call]p1: 3086 // For a function parameter pack that occurs at the end of the 3087 // parameter-declaration-list, the type A of each remaining argument of 3088 // the call is compared with the type P of the declarator-id of the 3089 // function parameter pack. Each comparison deduces template arguments 3090 // for subsequent positions in the template parameter packs expanded by 3091 // the function parameter pack. For a function parameter pack that does 3092 // not occur at the end of the parameter-declaration-list, the type of 3093 // the parameter pack is a non-deduced context. 3094 if (ParamIdx + 1 < NumParams) 3095 break; 3096 3097 QualType ParamPattern = ParamExpansion->getPattern(); 3098 SmallVector<unsigned, 2> PackIndices; 3099 { 3100 llvm::SmallBitVector SawIndices(TemplateParams->size()); 3101 SmallVector<UnexpandedParameterPack, 2> Unexpanded; 3102 collectUnexpandedParameterPacks(ParamPattern, Unexpanded); 3103 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { 3104 unsigned Depth, Index; 3105 llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); 3106 if (Depth == 0 && !SawIndices[Index]) { 3107 SawIndices[Index] = true; 3108 PackIndices.push_back(Index); 3109 } 3110 } 3111 } 3112 assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); 3113 3114 // Keep track of the deduced template arguments for each parameter pack 3115 // expanded by this pack expansion (the outer index) and for each 3116 // template argument (the inner SmallVectors). 3117 SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2> 3118 NewlyDeducedPacks(PackIndices.size()); 3119 SmallVector<DeducedTemplateArgument, 2> 3120 SavedPacks(PackIndices.size()); 3121 PrepareArgumentPackDeduction(*this, Deduced, PackIndices, SavedPacks, 3122 NewlyDeducedPacks); 3123 bool HasAnyArguments = false; 3124 for (; ArgIdx < Args.size(); ++ArgIdx) { 3125 HasAnyArguments = true; 3126 3127 QualType OrigParamType = ParamPattern; 3128 ParamType = OrigParamType; 3129 Expr *Arg = Args[ArgIdx]; 3130 QualType ArgType = Arg->getType(); 3131 3132 unsigned TDF = 0; 3133 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams, 3134 ParamType, ArgType, Arg, 3135 TDF)) { 3136 // We can't actually perform any deduction for this argument, so stop 3137 // deduction at this point. 3138 ++ArgIdx; 3139 break; 3140 } 3141 3142 // As above, initializer lists need special handling. 3143 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 3144 QualType X; 3145 if (!isStdInitializerList(ParamType, &X)) { 3146 ++ArgIdx; 3147 break; 3148 } 3149 3150 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 3151 if (TemplateDeductionResult Result = 3152 DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, X, 3153 ILE->getInit(i)->getType(), 3154 Info, Deduced, TDF)) 3155 return Result; 3156 } 3157 } else { 3158 3159 // Keep track of the argument type and corresponding argument index, 3160 // so we can check for compatibility between the deduced A and A. 3161 if (hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 3162 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx, 3163 ArgType)); 3164 3165 if (TemplateDeductionResult Result 3166 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3167 ParamType, ArgType, Info, 3168 Deduced, TDF)) 3169 return Result; 3170 } 3171 3172 // Capture the deduced template arguments for each parameter pack expanded 3173 // by this pack expansion, add them to the list of arguments we've deduced 3174 // for that pack, then clear out the deduced argument. 3175 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 3176 DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; 3177 if (!DeducedArg.isNull()) { 3178 NewlyDeducedPacks[I].push_back(DeducedArg); 3179 DeducedArg = DeducedTemplateArgument(); 3180 } 3181 } 3182 } 3183 3184 // Build argument packs for each of the parameter packs expanded by this 3185 // pack expansion. 3186 if (Sema::TemplateDeductionResult Result 3187 = FinishArgumentPackDeduction(*this, TemplateParams, HasAnyArguments, 3188 Deduced, PackIndices, SavedPacks, 3189 NewlyDeducedPacks, Info)) 3190 return Result; 3191 3192 // After we've matching against a parameter pack, we're done. 3193 break; 3194 } 3195 3196 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 3197 NumExplicitlySpecified, 3198 Specialization, Info, &OriginalCallArgs); 3199} 3200 3201/// \brief Deduce template arguments when taking the address of a function 3202/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 3203/// a template. 3204/// 3205/// \param FunctionTemplate the function template for which we are performing 3206/// template argument deduction. 3207/// 3208/// \param ExplicitTemplateArguments the explicitly-specified template 3209/// arguments. 3210/// 3211/// \param ArgFunctionType the function type that will be used as the 3212/// "argument" type (A) when performing template argument deduction from the 3213/// function template's function type. This type may be NULL, if there is no 3214/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 3215/// 3216/// \param Specialization if template argument deduction was successful, 3217/// this will be set to the function template specialization produced by 3218/// template argument deduction. 3219/// 3220/// \param Info the argument will be updated to provide additional information 3221/// about template argument deduction. 3222/// 3223/// \returns the result of template argument deduction. 3224Sema::TemplateDeductionResult 3225Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3226 TemplateArgumentListInfo *ExplicitTemplateArgs, 3227 QualType ArgFunctionType, 3228 FunctionDecl *&Specialization, 3229 TemplateDeductionInfo &Info) { 3230 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 3231 TemplateParameterList *TemplateParams 3232 = FunctionTemplate->getTemplateParameters(); 3233 QualType FunctionType = Function->getType(); 3234 3235 // Substitute any explicit template arguments. 3236 LocalInstantiationScope InstScope(*this); 3237 SmallVector<DeducedTemplateArgument, 4> Deduced; 3238 unsigned NumExplicitlySpecified = 0; 3239 SmallVector<QualType, 4> ParamTypes; 3240 if (ExplicitTemplateArgs) { 3241 if (TemplateDeductionResult Result 3242 = SubstituteExplicitTemplateArguments(FunctionTemplate, 3243 *ExplicitTemplateArgs, 3244 Deduced, ParamTypes, 3245 &FunctionType, Info)) 3246 return Result; 3247 3248 NumExplicitlySpecified = Deduced.size(); 3249 } 3250 3251 // Unevaluated SFINAE context. 3252 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 3253 SFINAETrap Trap(*this); 3254 3255 Deduced.resize(TemplateParams->size()); 3256 3257 if (!ArgFunctionType.isNull()) { 3258 // Deduce template arguments from the function type. 3259 if (TemplateDeductionResult Result 3260 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3261 FunctionType, ArgFunctionType, Info, 3262 Deduced, TDF_TopLevelParameterTypeList)) 3263 return Result; 3264 } 3265 3266 if (TemplateDeductionResult Result 3267 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 3268 NumExplicitlySpecified, 3269 Specialization, Info)) 3270 return Result; 3271 3272 // If the requested function type does not match the actual type of the 3273 // specialization, template argument deduction fails. 3274 if (!ArgFunctionType.isNull() && 3275 !Context.hasSameType(ArgFunctionType, Specialization->getType())) 3276 return TDK_NonDeducedMismatch; 3277 3278 return TDK_Success; 3279} 3280 3281/// \brief Deduce template arguments for a templated conversion 3282/// function (C++ [temp.deduct.conv]) and, if successful, produce a 3283/// conversion function template specialization. 3284Sema::TemplateDeductionResult 3285Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3286 QualType ToType, 3287 CXXConversionDecl *&Specialization, 3288 TemplateDeductionInfo &Info) { 3289 CXXConversionDecl *Conv 3290 = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()); 3291 QualType FromType = Conv->getConversionType(); 3292 3293 // Canonicalize the types for deduction. 3294 QualType P = Context.getCanonicalType(FromType); 3295 QualType A = Context.getCanonicalType(ToType); 3296 3297 // C++0x [temp.deduct.conv]p2: 3298 // If P is a reference type, the type referred to by P is used for 3299 // type deduction. 3300 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 3301 P = PRef->getPointeeType(); 3302 3303 // C++0x [temp.deduct.conv]p4: 3304 // [...] If A is a reference type, the type referred to by A is used 3305 // for type deduction. 3306 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 3307 A = ARef->getPointeeType().getUnqualifiedType(); 3308 // C++ [temp.deduct.conv]p3: 3309 // 3310 // If A is not a reference type: 3311 else { 3312 assert(!A->isReferenceType() && "Reference types were handled above"); 3313 3314 // - If P is an array type, the pointer type produced by the 3315 // array-to-pointer standard conversion (4.2) is used in place 3316 // of P for type deduction; otherwise, 3317 if (P->isArrayType()) 3318 P = Context.getArrayDecayedType(P); 3319 // - If P is a function type, the pointer type produced by the 3320 // function-to-pointer standard conversion (4.3) is used in 3321 // place of P for type deduction; otherwise, 3322 else if (P->isFunctionType()) 3323 P = Context.getPointerType(P); 3324 // - If P is a cv-qualified type, the top level cv-qualifiers of 3325 // P's type are ignored for type deduction. 3326 else 3327 P = P.getUnqualifiedType(); 3328 3329 // C++0x [temp.deduct.conv]p4: 3330 // If A is a cv-qualified type, the top level cv-qualifiers of A's 3331 // type are ignored for type deduction. If A is a reference type, the type 3332 // referred to by A is used for type deduction. 3333 A = A.getUnqualifiedType(); 3334 } 3335 3336 // Unevaluated SFINAE context. 3337 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 3338 SFINAETrap Trap(*this); 3339 3340 // C++ [temp.deduct.conv]p1: 3341 // Template argument deduction is done by comparing the return 3342 // type of the template conversion function (call it P) with the 3343 // type that is required as the result of the conversion (call it 3344 // A) as described in 14.8.2.4. 3345 TemplateParameterList *TemplateParams 3346 = FunctionTemplate->getTemplateParameters(); 3347 SmallVector<DeducedTemplateArgument, 4> Deduced; 3348 Deduced.resize(TemplateParams->size()); 3349 3350 // C++0x [temp.deduct.conv]p4: 3351 // In general, the deduction process attempts to find template 3352 // argument values that will make the deduced A identical to 3353 // A. However, there are two cases that allow a difference: 3354 unsigned TDF = 0; 3355 // - If the original A is a reference type, A can be more 3356 // cv-qualified than the deduced A (i.e., the type referred to 3357 // by the reference) 3358 if (ToType->isReferenceType()) 3359 TDF |= TDF_ParamWithReferenceType; 3360 // - The deduced A can be another pointer or pointer to member 3361 // type that can be converted to A via a qualification 3362 // conversion. 3363 // 3364 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 3365 // both P and A are pointers or member pointers. In this case, we 3366 // just ignore cv-qualifiers completely). 3367 if ((P->isPointerType() && A->isPointerType()) || 3368 (P->isMemberPointerType() && A->isMemberPointerType())) 3369 TDF |= TDF_IgnoreQualifiers; 3370 if (TemplateDeductionResult Result 3371 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3372 P, A, Info, Deduced, TDF)) 3373 return Result; 3374 3375 // Finish template argument deduction. 3376 LocalInstantiationScope InstScope(*this); 3377 FunctionDecl *Spec = 0; 3378 TemplateDeductionResult Result 3379 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, 3380 Info); 3381 Specialization = cast_or_null<CXXConversionDecl>(Spec); 3382 return Result; 3383} 3384 3385/// \brief Deduce template arguments for a function template when there is 3386/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 3387/// 3388/// \param FunctionTemplate the function template for which we are performing 3389/// template argument deduction. 3390/// 3391/// \param ExplicitTemplateArguments the explicitly-specified template 3392/// arguments. 3393/// 3394/// \param Specialization if template argument deduction was successful, 3395/// this will be set to the function template specialization produced by 3396/// template argument deduction. 3397/// 3398/// \param Info the argument will be updated to provide additional information 3399/// about template argument deduction. 3400/// 3401/// \returns the result of template argument deduction. 3402Sema::TemplateDeductionResult 3403Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3404 TemplateArgumentListInfo *ExplicitTemplateArgs, 3405 FunctionDecl *&Specialization, 3406 TemplateDeductionInfo &Info) { 3407 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3408 QualType(), Specialization, Info); 3409} 3410 3411namespace { 3412 /// Substitute the 'auto' type specifier within a type for a given replacement 3413 /// type. 3414 class SubstituteAutoTransform : 3415 public TreeTransform<SubstituteAutoTransform> { 3416 QualType Replacement; 3417 public: 3418 SubstituteAutoTransform(Sema &SemaRef, QualType Replacement) : 3419 TreeTransform<SubstituteAutoTransform>(SemaRef), Replacement(Replacement) { 3420 } 3421 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) { 3422 // If we're building the type pattern to deduce against, don't wrap the 3423 // substituted type in an AutoType. Certain template deduction rules 3424 // apply only when a template type parameter appears directly (and not if 3425 // the parameter is found through desugaring). For instance: 3426 // auto &&lref = lvalue; 3427 // must transform into "rvalue reference to T" not "rvalue reference to 3428 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply. 3429 if (isa<TemplateTypeParmType>(Replacement)) { 3430 QualType Result = Replacement; 3431 TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result); 3432 NewTL.setNameLoc(TL.getNameLoc()); 3433 return Result; 3434 } else { 3435 QualType Result = RebuildAutoType(Replacement); 3436 AutoTypeLoc NewTL = TLB.push<AutoTypeLoc>(Result); 3437 NewTL.setNameLoc(TL.getNameLoc()); 3438 return Result; 3439 } 3440 } 3441 3442 ExprResult TransformLambdaExpr(LambdaExpr *E) { 3443 // Lambdas never need to be transformed. 3444 return E; 3445 } 3446 }; 3447} 3448 3449/// \brief Deduce the type for an auto type-specifier (C++0x [dcl.spec.auto]p6) 3450/// 3451/// \param Type the type pattern using the auto type-specifier. 3452/// 3453/// \param Init the initializer for the variable whose type is to be deduced. 3454/// 3455/// \param Result if type deduction was successful, this will be set to the 3456/// deduced type. This may still contain undeduced autos if the type is 3457/// dependent. This will be set to null if deduction succeeded, but auto 3458/// substitution failed; the appropriate diagnostic will already have been 3459/// produced in that case. 3460Sema::DeduceAutoResult 3461Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, 3462 TypeSourceInfo *&Result) { 3463 if (Init->getType()->isNonOverloadPlaceholderType()) { 3464 ExprResult result = CheckPlaceholderExpr(Init); 3465 if (result.isInvalid()) return DAR_FailedAlreadyDiagnosed; 3466 Init = result.take(); 3467 } 3468 3469 if (Init->isTypeDependent()) { 3470 Result = Type; 3471 return DAR_Succeeded; 3472 } 3473 3474 SourceLocation Loc = Init->getExprLoc(); 3475 3476 LocalInstantiationScope InstScope(*this); 3477 3478 // Build template<class TemplParam> void Func(FuncParam); 3479 TemplateTypeParmDecl *TemplParam = 3480 TemplateTypeParmDecl::Create(Context, 0, SourceLocation(), Loc, 0, 0, 0, 3481 false, false); 3482 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0); 3483 NamedDecl *TemplParamPtr = TemplParam; 3484 FixedSizeTemplateParameterList<1> TemplateParams(Loc, Loc, &TemplParamPtr, 3485 Loc); 3486 3487 TypeSourceInfo *FuncParamInfo = 3488 SubstituteAutoTransform(*this, TemplArg).TransformType(Type); 3489 assert(FuncParamInfo && "substituting template parameter for 'auto' failed"); 3490 QualType FuncParam = FuncParamInfo->getType(); 3491 3492 // Deduce type of TemplParam in Func(Init) 3493 SmallVector<DeducedTemplateArgument, 1> Deduced; 3494 Deduced.resize(1); 3495 QualType InitType = Init->getType(); 3496 unsigned TDF = 0; 3497 if (AdjustFunctionParmAndArgTypesForDeduction(*this, &TemplateParams, 3498 FuncParam, InitType, Init, 3499 TDF)) 3500 return DAR_Failed; 3501 3502 TemplateDeductionInfo Info(Context, Loc); 3503 3504 InitListExpr * InitList = dyn_cast<InitListExpr>(Init); 3505 if (InitList) { 3506 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) { 3507 if (DeduceTemplateArgumentsByTypeMatch(*this, &TemplateParams, FuncParam, 3508 InitList->getInit(i)->getType(), 3509 Info, Deduced, TDF)) 3510 return DAR_Failed; 3511 } 3512 } else { 3513 if (DeduceTemplateArgumentsByTypeMatch(*this, &TemplateParams, FuncParam, 3514 InitType, Info, Deduced, TDF)) 3515 return DAR_Failed; 3516 } 3517 3518 QualType DeducedType = Deduced[0].getAsType(); 3519 if (DeducedType.isNull()) 3520 return DAR_Failed; 3521 3522 if (InitList) { 3523 DeducedType = BuildStdInitializerList(DeducedType, Loc); 3524 if (DeducedType.isNull()) 3525 return DAR_FailedAlreadyDiagnosed; 3526 } 3527 3528 Result = SubstituteAutoTransform(*this, DeducedType).TransformType(Type); 3529 3530 // Check that the deduced argument type is compatible with the original 3531 // argument type per C++ [temp.deduct.call]p4. 3532 if (!InitList && Result && 3533 CheckOriginalCallArgDeduction(*this, 3534 Sema::OriginalCallArg(FuncParam,0,InitType), 3535 Result->getType())) { 3536 Result = 0; 3537 return DAR_Failed; 3538 } 3539 3540 return DAR_Succeeded; 3541} 3542 3543void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) { 3544 if (isa<InitListExpr>(Init)) 3545 Diag(VDecl->getLocation(), 3546 diag::err_auto_var_deduction_failure_from_init_list) 3547 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange(); 3548 else 3549 Diag(VDecl->getLocation(), diag::err_auto_var_deduction_failure) 3550 << VDecl->getDeclName() << VDecl->getType() << Init->getType() 3551 << Init->getSourceRange(); 3552} 3553 3554static void 3555MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 3556 bool OnlyDeduced, 3557 unsigned Level, 3558 llvm::SmallBitVector &Deduced); 3559 3560/// \brief If this is a non-static member function, 3561static void MaybeAddImplicitObjectParameterType(ASTContext &Context, 3562 CXXMethodDecl *Method, 3563 SmallVectorImpl<QualType> &ArgTypes) { 3564 if (Method->isStatic()) 3565 return; 3566 3567 // C++ [over.match.funcs]p4: 3568 // 3569 // For non-static member functions, the type of the implicit 3570 // object parameter is 3571 // - "lvalue reference to cv X" for functions declared without a 3572 // ref-qualifier or with the & ref-qualifier 3573 // - "rvalue reference to cv X" for functions declared with the 3574 // && ref-qualifier 3575 // 3576 // FIXME: We don't have ref-qualifiers yet, so we don't do that part. 3577 QualType ArgTy = Context.getTypeDeclType(Method->getParent()); 3578 ArgTy = Context.getQualifiedType(ArgTy, 3579 Qualifiers::fromCVRMask(Method->getTypeQualifiers())); 3580 ArgTy = Context.getLValueReferenceType(ArgTy); 3581 ArgTypes.push_back(ArgTy); 3582} 3583 3584/// \brief Determine whether the function template \p FT1 is at least as 3585/// specialized as \p FT2. 3586static bool isAtLeastAsSpecializedAs(Sema &S, 3587 SourceLocation Loc, 3588 FunctionTemplateDecl *FT1, 3589 FunctionTemplateDecl *FT2, 3590 TemplatePartialOrderingContext TPOC, 3591 unsigned NumCallArguments, 3592 SmallVectorImpl<RefParamPartialOrderingComparison> *RefParamComparisons) { 3593 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 3594 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 3595 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 3596 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 3597 3598 assert(Proto1 && Proto2 && "Function templates must have prototypes"); 3599 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 3600 SmallVector<DeducedTemplateArgument, 4> Deduced; 3601 Deduced.resize(TemplateParams->size()); 3602 3603 // C++0x [temp.deduct.partial]p3: 3604 // The types used to determine the ordering depend on the context in which 3605 // the partial ordering is done: 3606 TemplateDeductionInfo Info(S.Context, Loc); 3607 CXXMethodDecl *Method1 = 0; 3608 CXXMethodDecl *Method2 = 0; 3609 bool IsNonStatic2 = false; 3610 bool IsNonStatic1 = false; 3611 unsigned Skip2 = 0; 3612 switch (TPOC) { 3613 case TPOC_Call: { 3614 // - In the context of a function call, the function parameter types are 3615 // used. 3616 Method1 = dyn_cast<CXXMethodDecl>(FD1); 3617 Method2 = dyn_cast<CXXMethodDecl>(FD2); 3618 IsNonStatic1 = Method1 && !Method1->isStatic(); 3619 IsNonStatic2 = Method2 && !Method2->isStatic(); 3620 3621 // C++0x [temp.func.order]p3: 3622 // [...] If only one of the function templates is a non-static 3623 // member, that function template is considered to have a new 3624 // first parameter inserted in its function parameter list. The 3625 // new parameter is of type "reference to cv A," where cv are 3626 // the cv-qualifiers of the function template (if any) and A is 3627 // the class of which the function template is a member. 3628 // 3629 // C++98/03 doesn't have this provision, so instead we drop the 3630 // first argument of the free function or static member, which 3631 // seems to match existing practice. 3632 SmallVector<QualType, 4> Args1; 3633 unsigned Skip1 = !S.getLangOpts().CPlusPlus0x && 3634 IsNonStatic2 && !IsNonStatic1; 3635 if (S.getLangOpts().CPlusPlus0x && IsNonStatic1 && !IsNonStatic2) 3636 MaybeAddImplicitObjectParameterType(S.Context, Method1, Args1); 3637 Args1.insert(Args1.end(), 3638 Proto1->arg_type_begin() + Skip1, Proto1->arg_type_end()); 3639 3640 SmallVector<QualType, 4> Args2; 3641 Skip2 = !S.getLangOpts().CPlusPlus0x && 3642 IsNonStatic1 && !IsNonStatic2; 3643 if (S.getLangOpts().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) 3644 MaybeAddImplicitObjectParameterType(S.Context, Method2, Args2); 3645 Args2.insert(Args2.end(), 3646 Proto2->arg_type_begin() + Skip2, Proto2->arg_type_end()); 3647 3648 // C++ [temp.func.order]p5: 3649 // The presence of unused ellipsis and default arguments has no effect on 3650 // the partial ordering of function templates. 3651 if (Args1.size() > NumCallArguments) 3652 Args1.resize(NumCallArguments); 3653 if (Args2.size() > NumCallArguments) 3654 Args2.resize(NumCallArguments); 3655 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(), 3656 Args1.data(), Args1.size(), Info, Deduced, 3657 TDF_None, /*PartialOrdering=*/true, 3658 RefParamComparisons)) 3659 return false; 3660 3661 break; 3662 } 3663 3664 case TPOC_Conversion: 3665 // - In the context of a call to a conversion operator, the return types 3666 // of the conversion function templates are used. 3667 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 3668 Proto2->getResultType(), 3669 Proto1->getResultType(), 3670 Info, Deduced, TDF_None, 3671 /*PartialOrdering=*/true, 3672 RefParamComparisons)) 3673 return false; 3674 break; 3675 3676 case TPOC_Other: 3677 // - In other contexts (14.6.6.2) the function template's function type 3678 // is used. 3679 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 3680 FD2->getType(), FD1->getType(), 3681 Info, Deduced, TDF_None, 3682 /*PartialOrdering=*/true, 3683 RefParamComparisons)) 3684 return false; 3685 break; 3686 } 3687 3688 // C++0x [temp.deduct.partial]p11: 3689 // In most cases, all template parameters must have values in order for 3690 // deduction to succeed, but for partial ordering purposes a template 3691 // parameter may remain without a value provided it is not used in the 3692 // types being used for partial ordering. [ Note: a template parameter used 3693 // in a non-deduced context is considered used. -end note] 3694 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 3695 for (; ArgIdx != NumArgs; ++ArgIdx) 3696 if (Deduced[ArgIdx].isNull()) 3697 break; 3698 3699 if (ArgIdx == NumArgs) { 3700 // All template arguments were deduced. FT1 is at least as specialized 3701 // as FT2. 3702 return true; 3703 } 3704 3705 // Figure out which template parameters were used. 3706 llvm::SmallBitVector UsedParameters(TemplateParams->size()); 3707 switch (TPOC) { 3708 case TPOC_Call: { 3709 unsigned NumParams = std::min(NumCallArguments, 3710 std::min(Proto1->getNumArgs(), 3711 Proto2->getNumArgs())); 3712 if (S.getLangOpts().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) 3713 ::MarkUsedTemplateParameters(S.Context, Method2->getThisType(S.Context), 3714 false, 3715 TemplateParams->getDepth(), UsedParameters); 3716 for (unsigned I = Skip2; I < NumParams; ++I) 3717 ::MarkUsedTemplateParameters(S.Context, Proto2->getArgType(I), false, 3718 TemplateParams->getDepth(), 3719 UsedParameters); 3720 break; 3721 } 3722 3723 case TPOC_Conversion: 3724 ::MarkUsedTemplateParameters(S.Context, Proto2->getResultType(), false, 3725 TemplateParams->getDepth(), 3726 UsedParameters); 3727 break; 3728 3729 case TPOC_Other: 3730 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false, 3731 TemplateParams->getDepth(), 3732 UsedParameters); 3733 break; 3734 } 3735 3736 for (; ArgIdx != NumArgs; ++ArgIdx) 3737 // If this argument had no value deduced but was used in one of the types 3738 // used for partial ordering, then deduction fails. 3739 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 3740 return false; 3741 3742 return true; 3743} 3744 3745/// \brief Determine whether this a function template whose parameter-type-list 3746/// ends with a function parameter pack. 3747static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) { 3748 FunctionDecl *Function = FunTmpl->getTemplatedDecl(); 3749 unsigned NumParams = Function->getNumParams(); 3750 if (NumParams == 0) 3751 return false; 3752 3753 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1); 3754 if (!Last->isParameterPack()) 3755 return false; 3756 3757 // Make sure that no previous parameter is a parameter pack. 3758 while (--NumParams > 0) { 3759 if (Function->getParamDecl(NumParams - 1)->isParameterPack()) 3760 return false; 3761 } 3762 3763 return true; 3764} 3765 3766/// \brief Returns the more specialized function template according 3767/// to the rules of function template partial ordering (C++ [temp.func.order]). 3768/// 3769/// \param FT1 the first function template 3770/// 3771/// \param FT2 the second function template 3772/// 3773/// \param TPOC the context in which we are performing partial ordering of 3774/// function templates. 3775/// 3776/// \param NumCallArguments The number of arguments in a call, used only 3777/// when \c TPOC is \c TPOC_Call. 3778/// 3779/// \returns the more specialized function template. If neither 3780/// template is more specialized, returns NULL. 3781FunctionTemplateDecl * 3782Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 3783 FunctionTemplateDecl *FT2, 3784 SourceLocation Loc, 3785 TemplatePartialOrderingContext TPOC, 3786 unsigned NumCallArguments) { 3787 SmallVector<RefParamPartialOrderingComparison, 4> RefParamComparisons; 3788 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 3789 NumCallArguments, 0); 3790 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 3791 NumCallArguments, 3792 &RefParamComparisons); 3793 3794 if (Better1 != Better2) // We have a clear winner 3795 return Better1? FT1 : FT2; 3796 3797 if (!Better1 && !Better2) // Neither is better than the other 3798 return 0; 3799 3800 // C++0x [temp.deduct.partial]p10: 3801 // If for each type being considered a given template is at least as 3802 // specialized for all types and more specialized for some set of types and 3803 // the other template is not more specialized for any types or is not at 3804 // least as specialized for any types, then the given template is more 3805 // specialized than the other template. Otherwise, neither template is more 3806 // specialized than the other. 3807 Better1 = false; 3808 Better2 = false; 3809 for (unsigned I = 0, N = RefParamComparisons.size(); I != N; ++I) { 3810 // C++0x [temp.deduct.partial]p9: 3811 // If, for a given type, deduction succeeds in both directions (i.e., the 3812 // types are identical after the transformations above) and both P and A 3813 // were reference types (before being replaced with the type referred to 3814 // above): 3815 3816 // -- if the type from the argument template was an lvalue reference 3817 // and the type from the parameter template was not, the argument 3818 // type is considered to be more specialized than the other; 3819 // otherwise, 3820 if (!RefParamComparisons[I].ArgIsRvalueRef && 3821 RefParamComparisons[I].ParamIsRvalueRef) { 3822 Better2 = true; 3823 if (Better1) 3824 return 0; 3825 continue; 3826 } else if (!RefParamComparisons[I].ParamIsRvalueRef && 3827 RefParamComparisons[I].ArgIsRvalueRef) { 3828 Better1 = true; 3829 if (Better2) 3830 return 0; 3831 continue; 3832 } 3833 3834 // -- if the type from the argument template is more cv-qualified than 3835 // the type from the parameter template (as described above), the 3836 // argument type is considered to be more specialized than the 3837 // other; otherwise, 3838 switch (RefParamComparisons[I].Qualifiers) { 3839 case NeitherMoreQualified: 3840 break; 3841 3842 case ParamMoreQualified: 3843 Better1 = true; 3844 if (Better2) 3845 return 0; 3846 continue; 3847 3848 case ArgMoreQualified: 3849 Better2 = true; 3850 if (Better1) 3851 return 0; 3852 continue; 3853 } 3854 3855 // -- neither type is more specialized than the other. 3856 } 3857 3858 assert(!(Better1 && Better2) && "Should have broken out in the loop above"); 3859 if (Better1) 3860 return FT1; 3861 else if (Better2) 3862 return FT2; 3863 3864 // FIXME: This mimics what GCC implements, but doesn't match up with the 3865 // proposed resolution for core issue 692. This area needs to be sorted out, 3866 // but for now we attempt to maintain compatibility. 3867 bool Variadic1 = isVariadicFunctionTemplate(FT1); 3868 bool Variadic2 = isVariadicFunctionTemplate(FT2); 3869 if (Variadic1 != Variadic2) 3870 return Variadic1? FT2 : FT1; 3871 3872 return 0; 3873} 3874 3875/// \brief Determine if the two templates are equivalent. 3876static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 3877 if (T1 == T2) 3878 return true; 3879 3880 if (!T1 || !T2) 3881 return false; 3882 3883 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 3884} 3885 3886/// \brief Retrieve the most specialized of the given function template 3887/// specializations. 3888/// 3889/// \param SpecBegin the start iterator of the function template 3890/// specializations that we will be comparing. 3891/// 3892/// \param SpecEnd the end iterator of the function template 3893/// specializations, paired with \p SpecBegin. 3894/// 3895/// \param TPOC the partial ordering context to use to compare the function 3896/// template specializations. 3897/// 3898/// \param NumCallArguments The number of arguments in a call, used only 3899/// when \c TPOC is \c TPOC_Call. 3900/// 3901/// \param Loc the location where the ambiguity or no-specializations 3902/// diagnostic should occur. 3903/// 3904/// \param NoneDiag partial diagnostic used to diagnose cases where there are 3905/// no matching candidates. 3906/// 3907/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 3908/// occurs. 3909/// 3910/// \param CandidateDiag partial diagnostic used for each function template 3911/// specialization that is a candidate in the ambiguous ordering. One parameter 3912/// in this diagnostic should be unbound, which will correspond to the string 3913/// describing the template arguments for the function template specialization. 3914/// 3915/// \param Index if non-NULL and the result of this function is non-nULL, 3916/// receives the index corresponding to the resulting function template 3917/// specialization. 3918/// 3919/// \returns the most specialized function template specialization, if 3920/// found. Otherwise, returns SpecEnd. 3921/// 3922/// \todo FIXME: Consider passing in the "also-ran" candidates that failed 3923/// template argument deduction. 3924UnresolvedSetIterator 3925Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, 3926 UnresolvedSetIterator SpecEnd, 3927 TemplatePartialOrderingContext TPOC, 3928 unsigned NumCallArguments, 3929 SourceLocation Loc, 3930 const PartialDiagnostic &NoneDiag, 3931 const PartialDiagnostic &AmbigDiag, 3932 const PartialDiagnostic &CandidateDiag, 3933 bool Complain, 3934 QualType TargetType) { 3935 if (SpecBegin == SpecEnd) { 3936 if (Complain) 3937 Diag(Loc, NoneDiag); 3938 return SpecEnd; 3939 } 3940 3941 if (SpecBegin + 1 == SpecEnd) 3942 return SpecBegin; 3943 3944 // Find the function template that is better than all of the templates it 3945 // has been compared to. 3946 UnresolvedSetIterator Best = SpecBegin; 3947 FunctionTemplateDecl *BestTemplate 3948 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 3949 assert(BestTemplate && "Not a function template specialization?"); 3950 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 3951 FunctionTemplateDecl *Challenger 3952 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 3953 assert(Challenger && "Not a function template specialization?"); 3954 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 3955 Loc, TPOC, NumCallArguments), 3956 Challenger)) { 3957 Best = I; 3958 BestTemplate = Challenger; 3959 } 3960 } 3961 3962 // Make sure that the "best" function template is more specialized than all 3963 // of the others. 3964 bool Ambiguous = false; 3965 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 3966 FunctionTemplateDecl *Challenger 3967 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 3968 if (I != Best && 3969 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 3970 Loc, TPOC, NumCallArguments), 3971 BestTemplate)) { 3972 Ambiguous = true; 3973 break; 3974 } 3975 } 3976 3977 if (!Ambiguous) { 3978 // We found an answer. Return it. 3979 return Best; 3980 } 3981 3982 // Diagnose the ambiguity. 3983 if (Complain) 3984 Diag(Loc, AmbigDiag); 3985 3986 if (Complain) 3987 // FIXME: Can we order the candidates in some sane way? 3988 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 3989 PartialDiagnostic PD = CandidateDiag; 3990 PD << getTemplateArgumentBindingsText( 3991 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(), 3992 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs()); 3993 if (!TargetType.isNull()) 3994 HandleFunctionTypeMismatch(PD, cast<FunctionDecl>(*I)->getType(), 3995 TargetType); 3996 Diag((*I)->getLocation(), PD); 3997 } 3998 3999 return SpecEnd; 4000} 4001 4002/// \brief Returns the more specialized class template partial specialization 4003/// according to the rules of partial ordering of class template partial 4004/// specializations (C++ [temp.class.order]). 4005/// 4006/// \param PS1 the first class template partial specialization 4007/// 4008/// \param PS2 the second class template partial specialization 4009/// 4010/// \returns the more specialized class template partial specialization. If 4011/// neither partial specialization is more specialized, returns NULL. 4012ClassTemplatePartialSpecializationDecl * 4013Sema::getMoreSpecializedPartialSpecialization( 4014 ClassTemplatePartialSpecializationDecl *PS1, 4015 ClassTemplatePartialSpecializationDecl *PS2, 4016 SourceLocation Loc) { 4017 // C++ [temp.class.order]p1: 4018 // For two class template partial specializations, the first is at least as 4019 // specialized as the second if, given the following rewrite to two 4020 // function templates, the first function template is at least as 4021 // specialized as the second according to the ordering rules for function 4022 // templates (14.6.6.2): 4023 // - the first function template has the same template parameters as the 4024 // first partial specialization and has a single function parameter 4025 // whose type is a class template specialization with the template 4026 // arguments of the first partial specialization, and 4027 // - the second function template has the same template parameters as the 4028 // second partial specialization and has a single function parameter 4029 // whose type is a class template specialization with the template 4030 // arguments of the second partial specialization. 4031 // 4032 // Rather than synthesize function templates, we merely perform the 4033 // equivalent partial ordering by performing deduction directly on 4034 // the template arguments of the class template partial 4035 // specializations. This computation is slightly simpler than the 4036 // general problem of function template partial ordering, because 4037 // class template partial specializations are more constrained. We 4038 // know that every template parameter is deducible from the class 4039 // template partial specialization's template arguments, for 4040 // example. 4041 SmallVector<DeducedTemplateArgument, 4> Deduced; 4042 TemplateDeductionInfo Info(Context, Loc); 4043 4044 QualType PT1 = PS1->getInjectedSpecializationType(); 4045 QualType PT2 = PS2->getInjectedSpecializationType(); 4046 4047 // Determine whether PS1 is at least as specialized as PS2 4048 Deduced.resize(PS2->getTemplateParameters()->size()); 4049 bool Better1 = !DeduceTemplateArgumentsByTypeMatch(*this, 4050 PS2->getTemplateParameters(), 4051 PT2, PT1, Info, Deduced, TDF_None, 4052 /*PartialOrdering=*/true, 4053 /*RefParamComparisons=*/0); 4054 if (Better1) { 4055 InstantiatingTemplate Inst(*this, PS2->getLocation(), PS2, 4056 Deduced.data(), Deduced.size(), Info); 4057 Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, 4058 PS1->getTemplateArgs(), 4059 Deduced, Info); 4060 } 4061 4062 // Determine whether PS2 is at least as specialized as PS1 4063 Deduced.clear(); 4064 Deduced.resize(PS1->getTemplateParameters()->size()); 4065 bool Better2 = !DeduceTemplateArgumentsByTypeMatch(*this, 4066 PS1->getTemplateParameters(), 4067 PT1, PT2, Info, Deduced, TDF_None, 4068 /*PartialOrdering=*/true, 4069 /*RefParamComparisons=*/0); 4070 if (Better2) { 4071 InstantiatingTemplate Inst(*this, PS1->getLocation(), PS1, 4072 Deduced.data(), Deduced.size(), Info); 4073 Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, 4074 PS2->getTemplateArgs(), 4075 Deduced, Info); 4076 } 4077 4078 if (Better1 == Better2) 4079 return 0; 4080 4081 return Better1? PS1 : PS2; 4082} 4083 4084static void 4085MarkUsedTemplateParameters(ASTContext &Ctx, 4086 const TemplateArgument &TemplateArg, 4087 bool OnlyDeduced, 4088 unsigned Depth, 4089 llvm::SmallBitVector &Used); 4090 4091/// \brief Mark the template parameters that are used by the given 4092/// expression. 4093static void 4094MarkUsedTemplateParameters(ASTContext &Ctx, 4095 const Expr *E, 4096 bool OnlyDeduced, 4097 unsigned Depth, 4098 llvm::SmallBitVector &Used) { 4099 // We can deduce from a pack expansion. 4100 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E)) 4101 E = Expansion->getPattern(); 4102 4103 // Skip through any implicit casts we added while type-checking. 4104 while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) 4105 E = ICE->getSubExpr(); 4106 4107 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to 4108 // find other occurrences of template parameters. 4109 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E); 4110 if (!DRE) 4111 return; 4112 4113 const NonTypeTemplateParmDecl *NTTP 4114 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 4115 if (!NTTP) 4116 return; 4117 4118 if (NTTP->getDepth() == Depth) 4119 Used[NTTP->getIndex()] = true; 4120} 4121 4122/// \brief Mark the template parameters that are used by the given 4123/// nested name specifier. 4124static void 4125MarkUsedTemplateParameters(ASTContext &Ctx, 4126 NestedNameSpecifier *NNS, 4127 bool OnlyDeduced, 4128 unsigned Depth, 4129 llvm::SmallBitVector &Used) { 4130 if (!NNS) 4131 return; 4132 4133 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth, 4134 Used); 4135 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0), 4136 OnlyDeduced, Depth, Used); 4137} 4138 4139/// \brief Mark the template parameters that are used by the given 4140/// template name. 4141static void 4142MarkUsedTemplateParameters(ASTContext &Ctx, 4143 TemplateName Name, 4144 bool OnlyDeduced, 4145 unsigned Depth, 4146 llvm::SmallBitVector &Used) { 4147 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 4148 if (TemplateTemplateParmDecl *TTP 4149 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 4150 if (TTP->getDepth() == Depth) 4151 Used[TTP->getIndex()] = true; 4152 } 4153 return; 4154 } 4155 4156 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 4157 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced, 4158 Depth, Used); 4159 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 4160 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced, 4161 Depth, Used); 4162} 4163 4164/// \brief Mark the template parameters that are used by the given 4165/// type. 4166static void 4167MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 4168 bool OnlyDeduced, 4169 unsigned Depth, 4170 llvm::SmallBitVector &Used) { 4171 if (T.isNull()) 4172 return; 4173 4174 // Non-dependent types have nothing deducible 4175 if (!T->isDependentType()) 4176 return; 4177 4178 T = Ctx.getCanonicalType(T); 4179 switch (T->getTypeClass()) { 4180 case Type::Pointer: 4181 MarkUsedTemplateParameters(Ctx, 4182 cast<PointerType>(T)->getPointeeType(), 4183 OnlyDeduced, 4184 Depth, 4185 Used); 4186 break; 4187 4188 case Type::BlockPointer: 4189 MarkUsedTemplateParameters(Ctx, 4190 cast<BlockPointerType>(T)->getPointeeType(), 4191 OnlyDeduced, 4192 Depth, 4193 Used); 4194 break; 4195 4196 case Type::LValueReference: 4197 case Type::RValueReference: 4198 MarkUsedTemplateParameters(Ctx, 4199 cast<ReferenceType>(T)->getPointeeType(), 4200 OnlyDeduced, 4201 Depth, 4202 Used); 4203 break; 4204 4205 case Type::MemberPointer: { 4206 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 4207 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced, 4208 Depth, Used); 4209 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0), 4210 OnlyDeduced, Depth, Used); 4211 break; 4212 } 4213 4214 case Type::DependentSizedArray: 4215 MarkUsedTemplateParameters(Ctx, 4216 cast<DependentSizedArrayType>(T)->getSizeExpr(), 4217 OnlyDeduced, Depth, Used); 4218 // Fall through to check the element type 4219 4220 case Type::ConstantArray: 4221 case Type::IncompleteArray: 4222 MarkUsedTemplateParameters(Ctx, 4223 cast<ArrayType>(T)->getElementType(), 4224 OnlyDeduced, Depth, Used); 4225 break; 4226 4227 case Type::Vector: 4228 case Type::ExtVector: 4229 MarkUsedTemplateParameters(Ctx, 4230 cast<VectorType>(T)->getElementType(), 4231 OnlyDeduced, Depth, Used); 4232 break; 4233 4234 case Type::DependentSizedExtVector: { 4235 const DependentSizedExtVectorType *VecType 4236 = cast<DependentSizedExtVectorType>(T); 4237 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced, 4238 Depth, Used); 4239 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, 4240 Depth, Used); 4241 break; 4242 } 4243 4244 case Type::FunctionProto: { 4245 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 4246 MarkUsedTemplateParameters(Ctx, Proto->getResultType(), OnlyDeduced, 4247 Depth, Used); 4248 for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) 4249 MarkUsedTemplateParameters(Ctx, Proto->getArgType(I), OnlyDeduced, 4250 Depth, Used); 4251 break; 4252 } 4253 4254 case Type::TemplateTypeParm: { 4255 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 4256 if (TTP->getDepth() == Depth) 4257 Used[TTP->getIndex()] = true; 4258 break; 4259 } 4260 4261 case Type::SubstTemplateTypeParmPack: { 4262 const SubstTemplateTypeParmPackType *Subst 4263 = cast<SubstTemplateTypeParmPackType>(T); 4264 MarkUsedTemplateParameters(Ctx, 4265 QualType(Subst->getReplacedParameter(), 0), 4266 OnlyDeduced, Depth, Used); 4267 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(), 4268 OnlyDeduced, Depth, Used); 4269 break; 4270 } 4271 4272 case Type::InjectedClassName: 4273 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 4274 // fall through 4275 4276 case Type::TemplateSpecialization: { 4277 const TemplateSpecializationType *Spec 4278 = cast<TemplateSpecializationType>(T); 4279 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced, 4280 Depth, Used); 4281 4282 // C++0x [temp.deduct.type]p9: 4283 // If the template argument list of P contains a pack expansion that is not 4284 // the last template argument, the entire template argument list is a 4285 // non-deduced context. 4286 if (OnlyDeduced && 4287 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) 4288 break; 4289 4290 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 4291 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 4292 Used); 4293 break; 4294 } 4295 4296 case Type::Complex: 4297 if (!OnlyDeduced) 4298 MarkUsedTemplateParameters(Ctx, 4299 cast<ComplexType>(T)->getElementType(), 4300 OnlyDeduced, Depth, Used); 4301 break; 4302 4303 case Type::Atomic: 4304 if (!OnlyDeduced) 4305 MarkUsedTemplateParameters(Ctx, 4306 cast<AtomicType>(T)->getValueType(), 4307 OnlyDeduced, Depth, Used); 4308 break; 4309 4310 case Type::DependentName: 4311 if (!OnlyDeduced) 4312 MarkUsedTemplateParameters(Ctx, 4313 cast<DependentNameType>(T)->getQualifier(), 4314 OnlyDeduced, Depth, Used); 4315 break; 4316 4317 case Type::DependentTemplateSpecialization: { 4318 const DependentTemplateSpecializationType *Spec 4319 = cast<DependentTemplateSpecializationType>(T); 4320 if (!OnlyDeduced) 4321 MarkUsedTemplateParameters(Ctx, Spec->getQualifier(), 4322 OnlyDeduced, Depth, Used); 4323 4324 // C++0x [temp.deduct.type]p9: 4325 // If the template argument list of P contains a pack expansion that is not 4326 // the last template argument, the entire template argument list is a 4327 // non-deduced context. 4328 if (OnlyDeduced && 4329 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) 4330 break; 4331 4332 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 4333 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 4334 Used); 4335 break; 4336 } 4337 4338 case Type::TypeOf: 4339 if (!OnlyDeduced) 4340 MarkUsedTemplateParameters(Ctx, 4341 cast<TypeOfType>(T)->getUnderlyingType(), 4342 OnlyDeduced, Depth, Used); 4343 break; 4344 4345 case Type::TypeOfExpr: 4346 if (!OnlyDeduced) 4347 MarkUsedTemplateParameters(Ctx, 4348 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 4349 OnlyDeduced, Depth, Used); 4350 break; 4351 4352 case Type::Decltype: 4353 if (!OnlyDeduced) 4354 MarkUsedTemplateParameters(Ctx, 4355 cast<DecltypeType>(T)->getUnderlyingExpr(), 4356 OnlyDeduced, Depth, Used); 4357 break; 4358 4359 case Type::UnaryTransform: 4360 if (!OnlyDeduced) 4361 MarkUsedTemplateParameters(Ctx, 4362 cast<UnaryTransformType>(T)->getUnderlyingType(), 4363 OnlyDeduced, Depth, Used); 4364 break; 4365 4366 case Type::PackExpansion: 4367 MarkUsedTemplateParameters(Ctx, 4368 cast<PackExpansionType>(T)->getPattern(), 4369 OnlyDeduced, Depth, Used); 4370 break; 4371 4372 case Type::Auto: 4373 MarkUsedTemplateParameters(Ctx, 4374 cast<AutoType>(T)->getDeducedType(), 4375 OnlyDeduced, Depth, Used); 4376 4377 // None of these types have any template parameters in them. 4378 case Type::Builtin: 4379 case Type::VariableArray: 4380 case Type::FunctionNoProto: 4381 case Type::Record: 4382 case Type::Enum: 4383 case Type::ObjCInterface: 4384 case Type::ObjCObject: 4385 case Type::ObjCObjectPointer: 4386 case Type::UnresolvedUsing: 4387#define TYPE(Class, Base) 4388#define ABSTRACT_TYPE(Class, Base) 4389#define DEPENDENT_TYPE(Class, Base) 4390#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 4391#include "clang/AST/TypeNodes.def" 4392 break; 4393 } 4394} 4395 4396/// \brief Mark the template parameters that are used by this 4397/// template argument. 4398static void 4399MarkUsedTemplateParameters(ASTContext &Ctx, 4400 const TemplateArgument &TemplateArg, 4401 bool OnlyDeduced, 4402 unsigned Depth, 4403 llvm::SmallBitVector &Used) { 4404 switch (TemplateArg.getKind()) { 4405 case TemplateArgument::Null: 4406 case TemplateArgument::Integral: 4407 case TemplateArgument::Declaration: 4408 break; 4409 4410 case TemplateArgument::Type: 4411 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced, 4412 Depth, Used); 4413 break; 4414 4415 case TemplateArgument::Template: 4416 case TemplateArgument::TemplateExpansion: 4417 MarkUsedTemplateParameters(Ctx, 4418 TemplateArg.getAsTemplateOrTemplatePattern(), 4419 OnlyDeduced, Depth, Used); 4420 break; 4421 4422 case TemplateArgument::Expression: 4423 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced, 4424 Depth, Used); 4425 break; 4426 4427 case TemplateArgument::Pack: 4428 for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), 4429 PEnd = TemplateArg.pack_end(); 4430 P != PEnd; ++P) 4431 MarkUsedTemplateParameters(Ctx, *P, OnlyDeduced, Depth, Used); 4432 break; 4433 } 4434} 4435 4436/// \brief Mark the template parameters can be deduced by the given 4437/// template argument list. 4438/// 4439/// \param TemplateArgs the template argument list from which template 4440/// parameters will be deduced. 4441/// 4442/// \param Deduced a bit vector whose elements will be set to \c true 4443/// to indicate when the corresponding template parameter will be 4444/// deduced. 4445void 4446Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 4447 bool OnlyDeduced, unsigned Depth, 4448 llvm::SmallBitVector &Used) { 4449 // C++0x [temp.deduct.type]p9: 4450 // If the template argument list of P contains a pack expansion that is not 4451 // the last template argument, the entire template argument list is a 4452 // non-deduced context. 4453 if (OnlyDeduced && 4454 hasPackExpansionBeforeEnd(TemplateArgs.data(), TemplateArgs.size())) 4455 return; 4456 4457 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 4458 ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced, 4459 Depth, Used); 4460} 4461 4462/// \brief Marks all of the template parameters that will be deduced by a 4463/// call to the given function template. 4464void 4465Sema::MarkDeducedTemplateParameters(ASTContext &Ctx, 4466 FunctionTemplateDecl *FunctionTemplate, 4467 llvm::SmallBitVector &Deduced) { 4468 TemplateParameterList *TemplateParams 4469 = FunctionTemplate->getTemplateParameters(); 4470 Deduced.clear(); 4471 Deduced.resize(TemplateParams->size()); 4472 4473 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 4474 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 4475 ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(), 4476 true, TemplateParams->getDepth(), Deduced); 4477} 4478 4479bool hasDeducibleTemplateParameters(Sema &S, 4480 FunctionTemplateDecl *FunctionTemplate, 4481 QualType T) { 4482 if (!T->isDependentType()) 4483 return false; 4484 4485 TemplateParameterList *TemplateParams 4486 = FunctionTemplate->getTemplateParameters(); 4487 llvm::SmallBitVector Deduced(TemplateParams->size()); 4488 ::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(), 4489 Deduced); 4490 4491 return Deduced.any(); 4492} 4493