SemaTemplateDeduction.cpp revision d10099e5c8238fa0327f03921cf2e3c8975c881e
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 isSameDeclaration(Param.getAsDecl(), Arg.getAsDecl())) 1590 return Sema::TDK_Success; 1591 1592 Info.FirstArg = Param; 1593 Info.SecondArg = Arg; 1594 return Sema::TDK_NonDeducedMismatch; 1595 1596 case TemplateArgument::Integral: 1597 if (Arg.getKind() == TemplateArgument::Integral) { 1598 if (hasSameExtendedValue(*Param.getAsIntegral(), *Arg.getAsIntegral())) 1599 return Sema::TDK_Success; 1600 1601 Info.FirstArg = Param; 1602 Info.SecondArg = Arg; 1603 return Sema::TDK_NonDeducedMismatch; 1604 } 1605 1606 if (Arg.getKind() == TemplateArgument::Expression) { 1607 Info.FirstArg = Param; 1608 Info.SecondArg = Arg; 1609 return Sema::TDK_NonDeducedMismatch; 1610 } 1611 1612 Info.FirstArg = Param; 1613 Info.SecondArg = Arg; 1614 return Sema::TDK_NonDeducedMismatch; 1615 1616 case TemplateArgument::Expression: { 1617 if (NonTypeTemplateParmDecl *NTTP 1618 = getDeducedParameterFromExpr(Param.getAsExpr())) { 1619 if (Arg.getKind() == TemplateArgument::Integral) 1620 return DeduceNonTypeTemplateArgument(S, NTTP, 1621 *Arg.getAsIntegral(), 1622 Arg.getIntegralType(), 1623 /*ArrayBound=*/false, 1624 Info, Deduced); 1625 if (Arg.getKind() == TemplateArgument::Expression) 1626 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsExpr(), 1627 Info, Deduced); 1628 if (Arg.getKind() == TemplateArgument::Declaration) 1629 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsDecl(), 1630 Info, Deduced); 1631 1632 Info.FirstArg = Param; 1633 Info.SecondArg = Arg; 1634 return Sema::TDK_NonDeducedMismatch; 1635 } 1636 1637 // Can't deduce anything, but that's okay. 1638 return Sema::TDK_Success; 1639 } 1640 case TemplateArgument::Pack: 1641 llvm_unreachable("Argument packs should be expanded by the caller!"); 1642 } 1643 1644 llvm_unreachable("Invalid TemplateArgument Kind!"); 1645} 1646 1647/// \brief Determine whether there is a template argument to be used for 1648/// deduction. 1649/// 1650/// This routine "expands" argument packs in-place, overriding its input 1651/// parameters so that \c Args[ArgIdx] will be the available template argument. 1652/// 1653/// \returns true if there is another template argument (which will be at 1654/// \c Args[ArgIdx]), false otherwise. 1655static bool hasTemplateArgumentForDeduction(const TemplateArgument *&Args, 1656 unsigned &ArgIdx, 1657 unsigned &NumArgs) { 1658 if (ArgIdx == NumArgs) 1659 return false; 1660 1661 const TemplateArgument &Arg = Args[ArgIdx]; 1662 if (Arg.getKind() != TemplateArgument::Pack) 1663 return true; 1664 1665 assert(ArgIdx == NumArgs - 1 && "Pack not at the end of argument list?"); 1666 Args = Arg.pack_begin(); 1667 NumArgs = Arg.pack_size(); 1668 ArgIdx = 0; 1669 return ArgIdx < NumArgs; 1670} 1671 1672/// \brief Determine whether the given set of template arguments has a pack 1673/// expansion that is not the last template argument. 1674static bool hasPackExpansionBeforeEnd(const TemplateArgument *Args, 1675 unsigned NumArgs) { 1676 unsigned ArgIdx = 0; 1677 while (ArgIdx < NumArgs) { 1678 const TemplateArgument &Arg = Args[ArgIdx]; 1679 1680 // Unwrap argument packs. 1681 if (Args[ArgIdx].getKind() == TemplateArgument::Pack) { 1682 Args = Arg.pack_begin(); 1683 NumArgs = Arg.pack_size(); 1684 ArgIdx = 0; 1685 continue; 1686 } 1687 1688 ++ArgIdx; 1689 if (ArgIdx == NumArgs) 1690 return false; 1691 1692 if (Arg.isPackExpansion()) 1693 return true; 1694 } 1695 1696 return false; 1697} 1698 1699static Sema::TemplateDeductionResult 1700DeduceTemplateArguments(Sema &S, 1701 TemplateParameterList *TemplateParams, 1702 const TemplateArgument *Params, unsigned NumParams, 1703 const TemplateArgument *Args, unsigned NumArgs, 1704 TemplateDeductionInfo &Info, 1705 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1706 bool NumberOfArgumentsMustMatch) { 1707 // C++0x [temp.deduct.type]p9: 1708 // If the template argument list of P contains a pack expansion that is not 1709 // the last template argument, the entire template argument list is a 1710 // non-deduced context. 1711 if (hasPackExpansionBeforeEnd(Params, NumParams)) 1712 return Sema::TDK_Success; 1713 1714 // C++0x [temp.deduct.type]p9: 1715 // If P has a form that contains <T> or <i>, then each argument Pi of the 1716 // respective template argument list P is compared with the corresponding 1717 // argument Ai of the corresponding template argument list of A. 1718 unsigned ArgIdx = 0, ParamIdx = 0; 1719 for (; hasTemplateArgumentForDeduction(Params, ParamIdx, NumParams); 1720 ++ParamIdx) { 1721 if (!Params[ParamIdx].isPackExpansion()) { 1722 // The simple case: deduce template arguments by matching Pi and Ai. 1723 1724 // Check whether we have enough arguments. 1725 if (!hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) 1726 return NumberOfArgumentsMustMatch? Sema::TDK_NonDeducedMismatch 1727 : Sema::TDK_Success; 1728 1729 if (Args[ArgIdx].isPackExpansion()) { 1730 // FIXME: We follow the logic of C++0x [temp.deduct.type]p22 here, 1731 // but applied to pack expansions that are template arguments. 1732 return Sema::TDK_NonDeducedMismatch; 1733 } 1734 1735 // Perform deduction for this Pi/Ai pair. 1736 if (Sema::TemplateDeductionResult Result 1737 = DeduceTemplateArguments(S, TemplateParams, 1738 Params[ParamIdx], Args[ArgIdx], 1739 Info, Deduced)) 1740 return Result; 1741 1742 // Move to the next argument. 1743 ++ArgIdx; 1744 continue; 1745 } 1746 1747 // The parameter is a pack expansion. 1748 1749 // C++0x [temp.deduct.type]p9: 1750 // If Pi is a pack expansion, then the pattern of Pi is compared with 1751 // each remaining argument in the template argument list of A. Each 1752 // comparison deduces template arguments for subsequent positions in the 1753 // template parameter packs expanded by Pi. 1754 TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern(); 1755 1756 // Compute the set of template parameter indices that correspond to 1757 // parameter packs expanded by the pack expansion. 1758 SmallVector<unsigned, 2> PackIndices; 1759 { 1760 llvm::SmallBitVector SawIndices(TemplateParams->size()); 1761 SmallVector<UnexpandedParameterPack, 2> Unexpanded; 1762 S.collectUnexpandedParameterPacks(Pattern, Unexpanded); 1763 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { 1764 unsigned Depth, Index; 1765 llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); 1766 if (Depth == 0 && !SawIndices[Index]) { 1767 SawIndices[Index] = true; 1768 PackIndices.push_back(Index); 1769 } 1770 } 1771 } 1772 assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); 1773 1774 // FIXME: If there are no remaining arguments, we can bail out early 1775 // and set any deduced parameter packs to an empty argument pack. 1776 // The latter part of this is a (minor) correctness issue. 1777 1778 // Save the deduced template arguments for each parameter pack expanded 1779 // by this pack expansion, then clear out the deduction. 1780 SmallVector<DeducedTemplateArgument, 2> 1781 SavedPacks(PackIndices.size()); 1782 SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2> 1783 NewlyDeducedPacks(PackIndices.size()); 1784 PrepareArgumentPackDeduction(S, Deduced, PackIndices, SavedPacks, 1785 NewlyDeducedPacks); 1786 1787 // Keep track of the deduced template arguments for each parameter pack 1788 // expanded by this pack expansion (the outer index) and for each 1789 // template argument (the inner SmallVectors). 1790 bool HasAnyArguments = false; 1791 while (hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) { 1792 HasAnyArguments = true; 1793 1794 // Deduce template arguments from the pattern. 1795 if (Sema::TemplateDeductionResult Result 1796 = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx], 1797 Info, Deduced)) 1798 return Result; 1799 1800 // Capture the deduced template arguments for each parameter pack expanded 1801 // by this pack expansion, add them to the list of arguments we've deduced 1802 // for that pack, then clear out the deduced argument. 1803 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 1804 DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; 1805 if (!DeducedArg.isNull()) { 1806 NewlyDeducedPacks[I].push_back(DeducedArg); 1807 DeducedArg = DeducedTemplateArgument(); 1808 } 1809 } 1810 1811 ++ArgIdx; 1812 } 1813 1814 // Build argument packs for each of the parameter packs expanded by this 1815 // pack expansion. 1816 if (Sema::TemplateDeductionResult Result 1817 = FinishArgumentPackDeduction(S, TemplateParams, HasAnyArguments, 1818 Deduced, PackIndices, SavedPacks, 1819 NewlyDeducedPacks, Info)) 1820 return Result; 1821 } 1822 1823 // If there is an argument remaining, then we had too many arguments. 1824 if (NumberOfArgumentsMustMatch && 1825 hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs)) 1826 return Sema::TDK_NonDeducedMismatch; 1827 1828 return Sema::TDK_Success; 1829} 1830 1831static Sema::TemplateDeductionResult 1832DeduceTemplateArguments(Sema &S, 1833 TemplateParameterList *TemplateParams, 1834 const TemplateArgumentList &ParamList, 1835 const TemplateArgumentList &ArgList, 1836 TemplateDeductionInfo &Info, 1837 SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 1838 return DeduceTemplateArguments(S, TemplateParams, 1839 ParamList.data(), ParamList.size(), 1840 ArgList.data(), ArgList.size(), 1841 Info, Deduced); 1842} 1843 1844/// \brief Determine whether two template arguments are the same. 1845static bool isSameTemplateArg(ASTContext &Context, 1846 const TemplateArgument &X, 1847 const TemplateArgument &Y) { 1848 if (X.getKind() != Y.getKind()) 1849 return false; 1850 1851 switch (X.getKind()) { 1852 case TemplateArgument::Null: 1853 llvm_unreachable("Comparing NULL template argument"); 1854 1855 case TemplateArgument::Type: 1856 return Context.getCanonicalType(X.getAsType()) == 1857 Context.getCanonicalType(Y.getAsType()); 1858 1859 case TemplateArgument::Declaration: 1860 return isSameDeclaration(X.getAsDecl(), Y.getAsDecl()); 1861 1862 case TemplateArgument::Template: 1863 case TemplateArgument::TemplateExpansion: 1864 return Context.getCanonicalTemplateName( 1865 X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() == 1866 Context.getCanonicalTemplateName( 1867 Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer(); 1868 1869 case TemplateArgument::Integral: 1870 return *X.getAsIntegral() == *Y.getAsIntegral(); 1871 1872 case TemplateArgument::Expression: { 1873 llvm::FoldingSetNodeID XID, YID; 1874 X.getAsExpr()->Profile(XID, Context, true); 1875 Y.getAsExpr()->Profile(YID, Context, true); 1876 return XID == YID; 1877 } 1878 1879 case TemplateArgument::Pack: 1880 if (X.pack_size() != Y.pack_size()) 1881 return false; 1882 1883 for (TemplateArgument::pack_iterator XP = X.pack_begin(), 1884 XPEnd = X.pack_end(), 1885 YP = Y.pack_begin(); 1886 XP != XPEnd; ++XP, ++YP) 1887 if (!isSameTemplateArg(Context, *XP, *YP)) 1888 return false; 1889 1890 return true; 1891 } 1892 1893 llvm_unreachable("Invalid TemplateArgument Kind!"); 1894} 1895 1896/// \brief Allocate a TemplateArgumentLoc where all locations have 1897/// been initialized to the given location. 1898/// 1899/// \param S The semantic analysis object. 1900/// 1901/// \param The template argument we are producing template argument 1902/// location information for. 1903/// 1904/// \param NTTPType For a declaration template argument, the type of 1905/// the non-type template parameter that corresponds to this template 1906/// argument. 1907/// 1908/// \param Loc The source location to use for the resulting template 1909/// argument. 1910static TemplateArgumentLoc 1911getTrivialTemplateArgumentLoc(Sema &S, 1912 const TemplateArgument &Arg, 1913 QualType NTTPType, 1914 SourceLocation Loc) { 1915 switch (Arg.getKind()) { 1916 case TemplateArgument::Null: 1917 llvm_unreachable("Can't get a NULL template argument here"); 1918 1919 case TemplateArgument::Type: 1920 return TemplateArgumentLoc(Arg, 1921 S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); 1922 1923 case TemplateArgument::Declaration: { 1924 Expr *E 1925 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 1926 .takeAs<Expr>(); 1927 return TemplateArgumentLoc(TemplateArgument(E), E); 1928 } 1929 1930 case TemplateArgument::Integral: { 1931 Expr *E 1932 = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>(); 1933 return TemplateArgumentLoc(TemplateArgument(E), E); 1934 } 1935 1936 case TemplateArgument::Template: 1937 case TemplateArgument::TemplateExpansion: { 1938 NestedNameSpecifierLocBuilder Builder; 1939 TemplateName Template = Arg.getAsTemplate(); 1940 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) 1941 Builder.MakeTrivial(S.Context, DTN->getQualifier(), Loc); 1942 else if (QualifiedTemplateName *QTN = Template.getAsQualifiedTemplateName()) 1943 Builder.MakeTrivial(S.Context, QTN->getQualifier(), Loc); 1944 1945 if (Arg.getKind() == TemplateArgument::Template) 1946 return TemplateArgumentLoc(Arg, 1947 Builder.getWithLocInContext(S.Context), 1948 Loc); 1949 1950 1951 return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(S.Context), 1952 Loc, Loc); 1953 } 1954 1955 case TemplateArgument::Expression: 1956 return TemplateArgumentLoc(Arg, Arg.getAsExpr()); 1957 1958 case TemplateArgument::Pack: 1959 return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo()); 1960 } 1961 1962 llvm_unreachable("Invalid TemplateArgument Kind!"); 1963} 1964 1965 1966/// \brief Convert the given deduced template argument and add it to the set of 1967/// fully-converted template arguments. 1968static bool ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param, 1969 DeducedTemplateArgument Arg, 1970 NamedDecl *Template, 1971 QualType NTTPType, 1972 unsigned ArgumentPackIndex, 1973 TemplateDeductionInfo &Info, 1974 bool InFunctionTemplate, 1975 SmallVectorImpl<TemplateArgument> &Output) { 1976 if (Arg.getKind() == TemplateArgument::Pack) { 1977 // This is a template argument pack, so check each of its arguments against 1978 // the template parameter. 1979 SmallVector<TemplateArgument, 2> PackedArgsBuilder; 1980 for (TemplateArgument::pack_iterator PA = Arg.pack_begin(), 1981 PAEnd = Arg.pack_end(); 1982 PA != PAEnd; ++PA) { 1983 // When converting the deduced template argument, append it to the 1984 // general output list. We need to do this so that the template argument 1985 // checking logic has all of the prior template arguments available. 1986 DeducedTemplateArgument InnerArg(*PA); 1987 InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound()); 1988 if (ConvertDeducedTemplateArgument(S, Param, InnerArg, Template, 1989 NTTPType, PackedArgsBuilder.size(), 1990 Info, InFunctionTemplate, Output)) 1991 return true; 1992 1993 // Move the converted template argument into our argument pack. 1994 PackedArgsBuilder.push_back(Output.back()); 1995 Output.pop_back(); 1996 } 1997 1998 // Create the resulting argument pack. 1999 Output.push_back(TemplateArgument::CreatePackCopy(S.Context, 2000 PackedArgsBuilder.data(), 2001 PackedArgsBuilder.size())); 2002 return false; 2003 } 2004 2005 // Convert the deduced template argument into a template 2006 // argument that we can check, almost as if the user had written 2007 // the template argument explicitly. 2008 TemplateArgumentLoc ArgLoc = getTrivialTemplateArgumentLoc(S, Arg, NTTPType, 2009 Info.getLocation()); 2010 2011 // Check the template argument, converting it as necessary. 2012 return S.CheckTemplateArgument(Param, ArgLoc, 2013 Template, 2014 Template->getLocation(), 2015 Template->getSourceRange().getEnd(), 2016 ArgumentPackIndex, 2017 Output, 2018 InFunctionTemplate 2019 ? (Arg.wasDeducedFromArrayBound() 2020 ? Sema::CTAK_DeducedFromArrayBound 2021 : Sema::CTAK_Deduced) 2022 : Sema::CTAK_Specified); 2023} 2024 2025/// Complete template argument deduction for a class template partial 2026/// specialization. 2027static Sema::TemplateDeductionResult 2028FinishTemplateArgumentDeduction(Sema &S, 2029 ClassTemplatePartialSpecializationDecl *Partial, 2030 const TemplateArgumentList &TemplateArgs, 2031 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2032 TemplateDeductionInfo &Info) { 2033 // Unevaluated SFINAE context. 2034 EnterExpressionEvaluationContext Unevaluated(S, Sema::Unevaluated); 2035 Sema::SFINAETrap Trap(S); 2036 2037 Sema::ContextRAII SavedContext(S, Partial); 2038 2039 // C++ [temp.deduct.type]p2: 2040 // [...] or if any template argument remains neither deduced nor 2041 // explicitly specified, template argument deduction fails. 2042 SmallVector<TemplateArgument, 4> Builder; 2043 TemplateParameterList *PartialParams = Partial->getTemplateParameters(); 2044 for (unsigned I = 0, N = PartialParams->size(); I != N; ++I) { 2045 NamedDecl *Param = PartialParams->getParam(I); 2046 if (Deduced[I].isNull()) { 2047 Info.Param = makeTemplateParameter(Param); 2048 return Sema::TDK_Incomplete; 2049 } 2050 2051 // We have deduced this argument, so it still needs to be 2052 // checked and converted. 2053 2054 // First, for a non-type template parameter type that is 2055 // initialized by a declaration, we need the type of the 2056 // corresponding non-type template parameter. 2057 QualType NTTPType; 2058 if (NonTypeTemplateParmDecl *NTTP 2059 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 2060 NTTPType = NTTP->getType(); 2061 if (NTTPType->isDependentType()) { 2062 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, 2063 Builder.data(), Builder.size()); 2064 NTTPType = S.SubstType(NTTPType, 2065 MultiLevelTemplateArgumentList(TemplateArgs), 2066 NTTP->getLocation(), 2067 NTTP->getDeclName()); 2068 if (NTTPType.isNull()) { 2069 Info.Param = makeTemplateParameter(Param); 2070 // FIXME: These template arguments are temporary. Free them! 2071 Info.reset(TemplateArgumentList::CreateCopy(S.Context, 2072 Builder.data(), 2073 Builder.size())); 2074 return Sema::TDK_SubstitutionFailure; 2075 } 2076 } 2077 } 2078 2079 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], 2080 Partial, NTTPType, 0, Info, false, 2081 Builder)) { 2082 Info.Param = makeTemplateParameter(Param); 2083 // FIXME: These template arguments are temporary. Free them! 2084 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder.data(), 2085 Builder.size())); 2086 return Sema::TDK_SubstitutionFailure; 2087 } 2088 } 2089 2090 // Form the template argument list from the deduced template arguments. 2091 TemplateArgumentList *DeducedArgumentList 2092 = TemplateArgumentList::CreateCopy(S.Context, Builder.data(), 2093 Builder.size()); 2094 2095 Info.reset(DeducedArgumentList); 2096 2097 // Substitute the deduced template arguments into the template 2098 // arguments of the class template partial specialization, and 2099 // verify that the instantiated template arguments are both valid 2100 // and are equivalent to the template arguments originally provided 2101 // to the class template. 2102 LocalInstantiationScope InstScope(S); 2103 ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); 2104 const TemplateArgumentLoc *PartialTemplateArgs 2105 = Partial->getTemplateArgsAsWritten(); 2106 2107 // Note that we don't provide the langle and rangle locations. 2108 TemplateArgumentListInfo InstArgs; 2109 2110 if (S.Subst(PartialTemplateArgs, 2111 Partial->getNumTemplateArgsAsWritten(), 2112 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) { 2113 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx; 2114 if (ParamIdx >= Partial->getTemplateParameters()->size()) 2115 ParamIdx = Partial->getTemplateParameters()->size() - 1; 2116 2117 Decl *Param 2118 = const_cast<NamedDecl *>( 2119 Partial->getTemplateParameters()->getParam(ParamIdx)); 2120 Info.Param = makeTemplateParameter(Param); 2121 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument(); 2122 return Sema::TDK_SubstitutionFailure; 2123 } 2124 2125 SmallVector<TemplateArgument, 4> ConvertedInstArgs; 2126 if (S.CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(), 2127 InstArgs, false, ConvertedInstArgs)) 2128 return Sema::TDK_SubstitutionFailure; 2129 2130 TemplateParameterList *TemplateParams 2131 = ClassTemplate->getTemplateParameters(); 2132 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) { 2133 TemplateArgument InstArg = ConvertedInstArgs.data()[I]; 2134 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) { 2135 Info.Param = makeTemplateParameter(TemplateParams->getParam(I)); 2136 Info.FirstArg = TemplateArgs[I]; 2137 Info.SecondArg = InstArg; 2138 return Sema::TDK_NonDeducedMismatch; 2139 } 2140 } 2141 2142 if (Trap.hasErrorOccurred()) 2143 return Sema::TDK_SubstitutionFailure; 2144 2145 return Sema::TDK_Success; 2146} 2147 2148/// \brief Perform template argument deduction to determine whether 2149/// the given template arguments match the given class template 2150/// partial specialization per C++ [temp.class.spec.match]. 2151Sema::TemplateDeductionResult 2152Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, 2153 const TemplateArgumentList &TemplateArgs, 2154 TemplateDeductionInfo &Info) { 2155 // C++ [temp.class.spec.match]p2: 2156 // A partial specialization matches a given actual template 2157 // argument list if the template arguments of the partial 2158 // specialization can be deduced from the actual template argument 2159 // list (14.8.2). 2160 2161 // Unevaluated SFINAE context. 2162 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 2163 SFINAETrap Trap(*this); 2164 2165 SmallVector<DeducedTemplateArgument, 4> Deduced; 2166 Deduced.resize(Partial->getTemplateParameters()->size()); 2167 if (TemplateDeductionResult Result 2168 = ::DeduceTemplateArguments(*this, 2169 Partial->getTemplateParameters(), 2170 Partial->getTemplateArgs(), 2171 TemplateArgs, Info, Deduced)) 2172 return Result; 2173 2174 InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, 2175 Deduced.data(), Deduced.size(), Info); 2176 if (Inst) 2177 return TDK_InstantiationDepth; 2178 2179 if (Trap.hasErrorOccurred()) 2180 return Sema::TDK_SubstitutionFailure; 2181 2182 return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs, 2183 Deduced, Info); 2184} 2185 2186/// \brief Determine whether the given type T is a simple-template-id type. 2187static bool isSimpleTemplateIdType(QualType T) { 2188 if (const TemplateSpecializationType *Spec 2189 = T->getAs<TemplateSpecializationType>()) 2190 return Spec->getTemplateName().getAsTemplateDecl() != 0; 2191 2192 return false; 2193} 2194 2195/// \brief Substitute the explicitly-provided template arguments into the 2196/// given function template according to C++ [temp.arg.explicit]. 2197/// 2198/// \param FunctionTemplate the function template into which the explicit 2199/// template arguments will be substituted. 2200/// 2201/// \param ExplicitTemplateArguments the explicitly-specified template 2202/// arguments. 2203/// 2204/// \param Deduced the deduced template arguments, which will be populated 2205/// with the converted and checked explicit template arguments. 2206/// 2207/// \param ParamTypes will be populated with the instantiated function 2208/// parameters. 2209/// 2210/// \param FunctionType if non-NULL, the result type of the function template 2211/// will also be instantiated and the pointed-to value will be updated with 2212/// the instantiated function type. 2213/// 2214/// \param Info if substitution fails for any reason, this object will be 2215/// populated with more information about the failure. 2216/// 2217/// \returns TDK_Success if substitution was successful, or some failure 2218/// condition. 2219Sema::TemplateDeductionResult 2220Sema::SubstituteExplicitTemplateArguments( 2221 FunctionTemplateDecl *FunctionTemplate, 2222 TemplateArgumentListInfo &ExplicitTemplateArgs, 2223 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2224 SmallVectorImpl<QualType> &ParamTypes, 2225 QualType *FunctionType, 2226 TemplateDeductionInfo &Info) { 2227 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2228 TemplateParameterList *TemplateParams 2229 = FunctionTemplate->getTemplateParameters(); 2230 2231 if (ExplicitTemplateArgs.size() == 0) { 2232 // No arguments to substitute; just copy over the parameter types and 2233 // fill in the function type. 2234 for (FunctionDecl::param_iterator P = Function->param_begin(), 2235 PEnd = Function->param_end(); 2236 P != PEnd; 2237 ++P) 2238 ParamTypes.push_back((*P)->getType()); 2239 2240 if (FunctionType) 2241 *FunctionType = Function->getType(); 2242 return TDK_Success; 2243 } 2244 2245 // Unevaluated SFINAE context. 2246 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 2247 SFINAETrap Trap(*this); 2248 2249 // C++ [temp.arg.explicit]p3: 2250 // Template arguments that are present shall be specified in the 2251 // declaration order of their corresponding template-parameters. The 2252 // template argument list shall not specify more template-arguments than 2253 // there are corresponding template-parameters. 2254 SmallVector<TemplateArgument, 4> Builder; 2255 2256 // Enter a new template instantiation context where we check the 2257 // explicitly-specified template arguments against this function template, 2258 // and then substitute them into the function parameter types. 2259 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 2260 FunctionTemplate, Deduced.data(), Deduced.size(), 2261 ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution, 2262 Info); 2263 if (Inst) 2264 return TDK_InstantiationDepth; 2265 2266 if (CheckTemplateArgumentList(FunctionTemplate, 2267 SourceLocation(), 2268 ExplicitTemplateArgs, 2269 true, 2270 Builder) || Trap.hasErrorOccurred()) { 2271 unsigned Index = Builder.size(); 2272 if (Index >= TemplateParams->size()) 2273 Index = TemplateParams->size() - 1; 2274 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index)); 2275 return TDK_InvalidExplicitArguments; 2276 } 2277 2278 // Form the template argument list from the explicitly-specified 2279 // template arguments. 2280 TemplateArgumentList *ExplicitArgumentList 2281 = TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size()); 2282 Info.reset(ExplicitArgumentList); 2283 2284 // Template argument deduction and the final substitution should be 2285 // done in the context of the templated declaration. Explicit 2286 // argument substitution, on the other hand, needs to happen in the 2287 // calling context. 2288 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 2289 2290 // If we deduced template arguments for a template parameter pack, 2291 // note that the template argument pack is partially substituted and record 2292 // the explicit template arguments. They'll be used as part of deduction 2293 // for this template parameter pack. 2294 for (unsigned I = 0, N = Builder.size(); I != N; ++I) { 2295 const TemplateArgument &Arg = Builder[I]; 2296 if (Arg.getKind() == TemplateArgument::Pack) { 2297 CurrentInstantiationScope->SetPartiallySubstitutedPack( 2298 TemplateParams->getParam(I), 2299 Arg.pack_begin(), 2300 Arg.pack_size()); 2301 break; 2302 } 2303 } 2304 2305 const FunctionProtoType *Proto 2306 = Function->getType()->getAs<FunctionProtoType>(); 2307 assert(Proto && "Function template does not have a prototype?"); 2308 2309 // Instantiate the types of each of the function parameters given the 2310 // explicitly-specified template arguments. If the function has a trailing 2311 // return type, substitute it after the arguments to ensure we substitute 2312 // in lexical order. 2313 if (Proto->hasTrailingReturn()) { 2314 if (SubstParmTypes(Function->getLocation(), 2315 Function->param_begin(), Function->getNumParams(), 2316 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 2317 ParamTypes)) 2318 return TDK_SubstitutionFailure; 2319 } 2320 2321 // Instantiate the return type. 2322 // FIXME: exception-specifications? 2323 QualType ResultType; 2324 { 2325 // C++11 [expr.prim.general]p3: 2326 // If a declaration declares a member function or member function 2327 // template of a class X, the expression this is a prvalue of type 2328 // "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq 2329 // and the end of the function-definition, member-declarator, or 2330 // declarator. 2331 unsigned ThisTypeQuals = 0; 2332 CXXRecordDecl *ThisContext = 0; 2333 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2334 ThisContext = Method->getParent(); 2335 ThisTypeQuals = Method->getTypeQualifiers(); 2336 } 2337 2338 CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals, 2339 getLangOpts().CPlusPlus0x); 2340 2341 ResultType = SubstType(Proto->getResultType(), 2342 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 2343 Function->getTypeSpecStartLoc(), 2344 Function->getDeclName()); 2345 if (ResultType.isNull() || Trap.hasErrorOccurred()) 2346 return TDK_SubstitutionFailure; 2347 } 2348 2349 // Instantiate the types of each of the function parameters given the 2350 // explicitly-specified template arguments if we didn't do so earlier. 2351 if (!Proto->hasTrailingReturn() && 2352 SubstParmTypes(Function->getLocation(), 2353 Function->param_begin(), Function->getNumParams(), 2354 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 2355 ParamTypes)) 2356 return TDK_SubstitutionFailure; 2357 2358 if (FunctionType) { 2359 *FunctionType = BuildFunctionType(ResultType, 2360 ParamTypes.data(), ParamTypes.size(), 2361 Proto->isVariadic(), 2362 Proto->hasTrailingReturn(), 2363 Proto->getTypeQuals(), 2364 Proto->getRefQualifier(), 2365 Function->getLocation(), 2366 Function->getDeclName(), 2367 Proto->getExtInfo()); 2368 if (FunctionType->isNull() || Trap.hasErrorOccurred()) 2369 return TDK_SubstitutionFailure; 2370 } 2371 2372 // C++ [temp.arg.explicit]p2: 2373 // Trailing template arguments that can be deduced (14.8.2) may be 2374 // omitted from the list of explicit template-arguments. If all of the 2375 // template arguments can be deduced, they may all be omitted; in this 2376 // case, the empty template argument list <> itself may also be omitted. 2377 // 2378 // Take all of the explicitly-specified arguments and put them into 2379 // the set of deduced template arguments. Explicitly-specified 2380 // parameter packs, however, will be set to NULL since the deduction 2381 // mechanisms handle explicitly-specified argument packs directly. 2382 Deduced.reserve(TemplateParams->size()); 2383 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) { 2384 const TemplateArgument &Arg = ExplicitArgumentList->get(I); 2385 if (Arg.getKind() == TemplateArgument::Pack) 2386 Deduced.push_back(DeducedTemplateArgument()); 2387 else 2388 Deduced.push_back(Arg); 2389 } 2390 2391 return TDK_Success; 2392} 2393 2394/// \brief Check whether the deduced argument type for a call to a function 2395/// template matches the actual argument type per C++ [temp.deduct.call]p4. 2396static bool 2397CheckOriginalCallArgDeduction(Sema &S, Sema::OriginalCallArg OriginalArg, 2398 QualType DeducedA) { 2399 ASTContext &Context = S.Context; 2400 2401 QualType A = OriginalArg.OriginalArgType; 2402 QualType OriginalParamType = OriginalArg.OriginalParamType; 2403 2404 // Check for type equality (top-level cv-qualifiers are ignored). 2405 if (Context.hasSameUnqualifiedType(A, DeducedA)) 2406 return false; 2407 2408 // Strip off references on the argument types; they aren't needed for 2409 // the following checks. 2410 if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>()) 2411 DeducedA = DeducedARef->getPointeeType(); 2412 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 2413 A = ARef->getPointeeType(); 2414 2415 // C++ [temp.deduct.call]p4: 2416 // [...] However, there are three cases that allow a difference: 2417 // - If the original P is a reference type, the deduced A (i.e., the 2418 // type referred to by the reference) can be more cv-qualified than 2419 // the transformed A. 2420 if (const ReferenceType *OriginalParamRef 2421 = OriginalParamType->getAs<ReferenceType>()) { 2422 // We don't want to keep the reference around any more. 2423 OriginalParamType = OriginalParamRef->getPointeeType(); 2424 2425 Qualifiers AQuals = A.getQualifiers(); 2426 Qualifiers DeducedAQuals = DeducedA.getQualifiers(); 2427 if (AQuals == DeducedAQuals) { 2428 // Qualifiers match; there's nothing to do. 2429 } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) { 2430 return true; 2431 } else { 2432 // Qualifiers are compatible, so have the argument type adopt the 2433 // deduced argument type's qualifiers as if we had performed the 2434 // qualification conversion. 2435 A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals); 2436 } 2437 } 2438 2439 // - The transformed A can be another pointer or pointer to member 2440 // type that can be converted to the deduced A via a qualification 2441 // conversion. 2442 // 2443 // Also allow conversions which merely strip [[noreturn]] from function types 2444 // (recursively) as an extension. 2445 // FIXME: Currently, this doesn't place nicely with qualfication conversions. 2446 bool ObjCLifetimeConversion = false; 2447 QualType ResultTy; 2448 if ((A->isAnyPointerType() || A->isMemberPointerType()) && 2449 (S.IsQualificationConversion(A, DeducedA, false, 2450 ObjCLifetimeConversion) || 2451 S.IsNoReturnConversion(A, DeducedA, ResultTy))) 2452 return false; 2453 2454 2455 // - If P is a class and P has the form simple-template-id, then the 2456 // transformed A can be a derived class of the deduced A. [...] 2457 // [...] Likewise, if P is a pointer to a class of the form 2458 // simple-template-id, the transformed A can be a pointer to a 2459 // derived class pointed to by the deduced A. 2460 if (const PointerType *OriginalParamPtr 2461 = OriginalParamType->getAs<PointerType>()) { 2462 if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) { 2463 if (const PointerType *APtr = A->getAs<PointerType>()) { 2464 if (A->getPointeeType()->isRecordType()) { 2465 OriginalParamType = OriginalParamPtr->getPointeeType(); 2466 DeducedA = DeducedAPtr->getPointeeType(); 2467 A = APtr->getPointeeType(); 2468 } 2469 } 2470 } 2471 } 2472 2473 if (Context.hasSameUnqualifiedType(A, DeducedA)) 2474 return false; 2475 2476 if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) && 2477 S.IsDerivedFrom(A, DeducedA)) 2478 return false; 2479 2480 return true; 2481} 2482 2483/// \brief Finish template argument deduction for a function template, 2484/// checking the deduced template arguments for completeness and forming 2485/// the function template specialization. 2486/// 2487/// \param OriginalCallArgs If non-NULL, the original call arguments against 2488/// which the deduced argument types should be compared. 2489Sema::TemplateDeductionResult 2490Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate, 2491 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2492 unsigned NumExplicitlySpecified, 2493 FunctionDecl *&Specialization, 2494 TemplateDeductionInfo &Info, 2495 SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs) { 2496 TemplateParameterList *TemplateParams 2497 = FunctionTemplate->getTemplateParameters(); 2498 2499 // Unevaluated SFINAE context. 2500 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 2501 SFINAETrap Trap(*this); 2502 2503 // Enter a new template instantiation context while we instantiate the 2504 // actual function declaration. 2505 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 2506 FunctionTemplate, Deduced.data(), Deduced.size(), 2507 ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution, 2508 Info); 2509 if (Inst) 2510 return TDK_InstantiationDepth; 2511 2512 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 2513 2514 // C++ [temp.deduct.type]p2: 2515 // [...] or if any template argument remains neither deduced nor 2516 // explicitly specified, template argument deduction fails. 2517 SmallVector<TemplateArgument, 4> Builder; 2518 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) { 2519 NamedDecl *Param = TemplateParams->getParam(I); 2520 2521 if (!Deduced[I].isNull()) { 2522 if (I < NumExplicitlySpecified) { 2523 // We have already fully type-checked and converted this 2524 // argument, because it was explicitly-specified. Just record the 2525 // presence of this argument. 2526 Builder.push_back(Deduced[I]); 2527 continue; 2528 } 2529 2530 // We have deduced this argument, so it still needs to be 2531 // checked and converted. 2532 2533 // First, for a non-type template parameter type that is 2534 // initialized by a declaration, we need the type of the 2535 // corresponding non-type template parameter. 2536 QualType NTTPType; 2537 if (NonTypeTemplateParmDecl *NTTP 2538 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 2539 NTTPType = NTTP->getType(); 2540 if (NTTPType->isDependentType()) { 2541 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, 2542 Builder.data(), Builder.size()); 2543 NTTPType = SubstType(NTTPType, 2544 MultiLevelTemplateArgumentList(TemplateArgs), 2545 NTTP->getLocation(), 2546 NTTP->getDeclName()); 2547 if (NTTPType.isNull()) { 2548 Info.Param = makeTemplateParameter(Param); 2549 // FIXME: These template arguments are temporary. Free them! 2550 Info.reset(TemplateArgumentList::CreateCopy(Context, 2551 Builder.data(), 2552 Builder.size())); 2553 return TDK_SubstitutionFailure; 2554 } 2555 } 2556 } 2557 2558 if (ConvertDeducedTemplateArgument(*this, Param, Deduced[I], 2559 FunctionTemplate, NTTPType, 0, Info, 2560 true, Builder)) { 2561 Info.Param = makeTemplateParameter(Param); 2562 // FIXME: These template arguments are temporary. Free them! 2563 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), 2564 Builder.size())); 2565 return TDK_SubstitutionFailure; 2566 } 2567 2568 continue; 2569 } 2570 2571 // C++0x [temp.arg.explicit]p3: 2572 // A trailing template parameter pack (14.5.3) not otherwise deduced will 2573 // be deduced to an empty sequence of template arguments. 2574 // FIXME: Where did the word "trailing" come from? 2575 if (Param->isTemplateParameterPack()) { 2576 // We may have had explicitly-specified template arguments for this 2577 // template parameter pack. If so, our empty deduction extends the 2578 // explicitly-specified set (C++0x [temp.arg.explicit]p9). 2579 const TemplateArgument *ExplicitArgs; 2580 unsigned NumExplicitArgs; 2581 if (CurrentInstantiationScope->getPartiallySubstitutedPack(&ExplicitArgs, 2582 &NumExplicitArgs) 2583 == Param) 2584 Builder.push_back(TemplateArgument(ExplicitArgs, NumExplicitArgs)); 2585 else 2586 Builder.push_back(TemplateArgument(0, 0)); 2587 2588 continue; 2589 } 2590 2591 // Substitute into the default template argument, if available. 2592 TemplateArgumentLoc DefArg 2593 = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate, 2594 FunctionTemplate->getLocation(), 2595 FunctionTemplate->getSourceRange().getEnd(), 2596 Param, 2597 Builder); 2598 2599 // If there was no default argument, deduction is incomplete. 2600 if (DefArg.getArgument().isNull()) { 2601 Info.Param = makeTemplateParameter( 2602 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 2603 return TDK_Incomplete; 2604 } 2605 2606 // Check whether we can actually use the default argument. 2607 if (CheckTemplateArgument(Param, DefArg, 2608 FunctionTemplate, 2609 FunctionTemplate->getLocation(), 2610 FunctionTemplate->getSourceRange().getEnd(), 2611 0, Builder, 2612 CTAK_Specified)) { 2613 Info.Param = makeTemplateParameter( 2614 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 2615 // FIXME: These template arguments are temporary. Free them! 2616 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder.data(), 2617 Builder.size())); 2618 return TDK_SubstitutionFailure; 2619 } 2620 2621 // If we get here, we successfully used the default template argument. 2622 } 2623 2624 // Form the template argument list from the deduced template arguments. 2625 TemplateArgumentList *DeducedArgumentList 2626 = TemplateArgumentList::CreateCopy(Context, Builder.data(), Builder.size()); 2627 Info.reset(DeducedArgumentList); 2628 2629 // Substitute the deduced template arguments into the function template 2630 // declaration to produce the function template specialization. 2631 DeclContext *Owner = FunctionTemplate->getDeclContext(); 2632 if (FunctionTemplate->getFriendObjectKind()) 2633 Owner = FunctionTemplate->getLexicalDeclContext(); 2634 Specialization = cast_or_null<FunctionDecl>( 2635 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, 2636 MultiLevelTemplateArgumentList(*DeducedArgumentList))); 2637 if (!Specialization || Specialization->isInvalidDecl()) 2638 return TDK_SubstitutionFailure; 2639 2640 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() == 2641 FunctionTemplate->getCanonicalDecl()); 2642 2643 // If the template argument list is owned by the function template 2644 // specialization, release it. 2645 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList && 2646 !Trap.hasErrorOccurred()) 2647 Info.take(); 2648 2649 // There may have been an error that did not prevent us from constructing a 2650 // declaration. Mark the declaration invalid and return with a substitution 2651 // failure. 2652 if (Trap.hasErrorOccurred()) { 2653 Specialization->setInvalidDecl(true); 2654 return TDK_SubstitutionFailure; 2655 } 2656 2657 if (OriginalCallArgs) { 2658 // C++ [temp.deduct.call]p4: 2659 // In general, the deduction process attempts to find template argument 2660 // values that will make the deduced A identical to A (after the type A 2661 // is transformed as described above). [...] 2662 for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) { 2663 OriginalCallArg OriginalArg = (*OriginalCallArgs)[I]; 2664 unsigned ParamIdx = OriginalArg.ArgIdx; 2665 2666 if (ParamIdx >= Specialization->getNumParams()) 2667 continue; 2668 2669 QualType DeducedA = Specialization->getParamDecl(ParamIdx)->getType(); 2670 if (CheckOriginalCallArgDeduction(*this, OriginalArg, DeducedA)) 2671 return Sema::TDK_SubstitutionFailure; 2672 } 2673 } 2674 2675 // If we suppressed any diagnostics while performing template argument 2676 // deduction, and if we haven't already instantiated this declaration, 2677 // keep track of these diagnostics. They'll be emitted if this specialization 2678 // is actually used. 2679 if (Info.diag_begin() != Info.diag_end()) { 2680 llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, 1> >::iterator 2681 Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl()); 2682 if (Pos == SuppressedDiagnostics.end()) 2683 SuppressedDiagnostics[Specialization->getCanonicalDecl()] 2684 .append(Info.diag_begin(), Info.diag_end()); 2685 } 2686 2687 return TDK_Success; 2688} 2689 2690/// Gets the type of a function for template-argument-deducton 2691/// purposes when it's considered as part of an overload set. 2692static QualType GetTypeOfFunction(ASTContext &Context, 2693 const OverloadExpr::FindResult &R, 2694 FunctionDecl *Fn) { 2695 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) 2696 if (Method->isInstance()) { 2697 // An instance method that's referenced in a form that doesn't 2698 // look like a member pointer is just invalid. 2699 if (!R.HasFormOfMemberPointer) return QualType(); 2700 2701 return Context.getMemberPointerType(Fn->getType(), 2702 Context.getTypeDeclType(Method->getParent()).getTypePtr()); 2703 } 2704 2705 if (!R.IsAddressOfOperand) return Fn->getType(); 2706 return Context.getPointerType(Fn->getType()); 2707} 2708 2709/// Apply the deduction rules for overload sets. 2710/// 2711/// \return the null type if this argument should be treated as an 2712/// undeduced context 2713static QualType 2714ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, 2715 Expr *Arg, QualType ParamType, 2716 bool ParamWasReference) { 2717 2718 OverloadExpr::FindResult R = OverloadExpr::find(Arg); 2719 2720 OverloadExpr *Ovl = R.Expression; 2721 2722 // C++0x [temp.deduct.call]p4 2723 unsigned TDF = 0; 2724 if (ParamWasReference) 2725 TDF |= TDF_ParamWithReferenceType; 2726 if (R.IsAddressOfOperand) 2727 TDF |= TDF_IgnoreQualifiers; 2728 2729 // C++0x [temp.deduct.call]p6: 2730 // When P is a function type, pointer to function type, or pointer 2731 // to member function type: 2732 2733 if (!ParamType->isFunctionType() && 2734 !ParamType->isFunctionPointerType() && 2735 !ParamType->isMemberFunctionPointerType()) { 2736 if (Ovl->hasExplicitTemplateArgs()) { 2737 // But we can still look for an explicit specialization. 2738 if (FunctionDecl *ExplicitSpec 2739 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 2740 return GetTypeOfFunction(S.Context, R, ExplicitSpec); 2741 } 2742 2743 return QualType(); 2744 } 2745 2746 // Gather the explicit template arguments, if any. 2747 TemplateArgumentListInfo ExplicitTemplateArgs; 2748 if (Ovl->hasExplicitTemplateArgs()) 2749 Ovl->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 2750 QualType Match; 2751 for (UnresolvedSetIterator I = Ovl->decls_begin(), 2752 E = Ovl->decls_end(); I != E; ++I) { 2753 NamedDecl *D = (*I)->getUnderlyingDecl(); 2754 2755 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) { 2756 // - If the argument is an overload set containing one or more 2757 // function templates, the parameter is treated as a 2758 // non-deduced context. 2759 if (!Ovl->hasExplicitTemplateArgs()) 2760 return QualType(); 2761 2762 // Otherwise, see if we can resolve a function type 2763 FunctionDecl *Specialization = 0; 2764 TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 2765 if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs, 2766 Specialization, Info)) 2767 continue; 2768 2769 D = Specialization; 2770 } 2771 2772 FunctionDecl *Fn = cast<FunctionDecl>(D); 2773 QualType ArgType = GetTypeOfFunction(S.Context, R, Fn); 2774 if (ArgType.isNull()) continue; 2775 2776 // Function-to-pointer conversion. 2777 if (!ParamWasReference && ParamType->isPointerType() && 2778 ArgType->isFunctionType()) 2779 ArgType = S.Context.getPointerType(ArgType); 2780 2781 // - If the argument is an overload set (not containing function 2782 // templates), trial argument deduction is attempted using each 2783 // of the members of the set. If deduction succeeds for only one 2784 // of the overload set members, that member is used as the 2785 // argument value for the deduction. If deduction succeeds for 2786 // more than one member of the overload set the parameter is 2787 // treated as a non-deduced context. 2788 2789 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 2790 // Type deduction is done independently for each P/A pair, and 2791 // the deduced template argument values are then combined. 2792 // So we do not reject deductions which were made elsewhere. 2793 SmallVector<DeducedTemplateArgument, 8> 2794 Deduced(TemplateParams->size()); 2795 TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 2796 Sema::TemplateDeductionResult Result 2797 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 2798 ArgType, Info, Deduced, TDF); 2799 if (Result) continue; 2800 if (!Match.isNull()) return QualType(); 2801 Match = ArgType; 2802 } 2803 2804 return Match; 2805} 2806 2807/// \brief Perform the adjustments to the parameter and argument types 2808/// described in C++ [temp.deduct.call]. 2809/// 2810/// \returns true if the caller should not attempt to perform any template 2811/// argument deduction based on this P/A pair. 2812static bool AdjustFunctionParmAndArgTypesForDeduction(Sema &S, 2813 TemplateParameterList *TemplateParams, 2814 QualType &ParamType, 2815 QualType &ArgType, 2816 Expr *Arg, 2817 unsigned &TDF) { 2818 // C++0x [temp.deduct.call]p3: 2819 // If P is a cv-qualified type, the top level cv-qualifiers of P's type 2820 // are ignored for type deduction. 2821 if (ParamType.hasQualifiers()) 2822 ParamType = ParamType.getUnqualifiedType(); 2823 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>(); 2824 if (ParamRefType) { 2825 QualType PointeeType = ParamRefType->getPointeeType(); 2826 2827 // If the argument has incomplete array type, try to complete it's type. 2828 if (ArgType->isIncompleteArrayType() && !S.RequireCompleteExprType(Arg, 0)) 2829 ArgType = Arg->getType(); 2830 2831 // [C++0x] If P is an rvalue reference to a cv-unqualified 2832 // template parameter and the argument is an lvalue, the type 2833 // "lvalue reference to A" is used in place of A for type 2834 // deduction. 2835 if (isa<RValueReferenceType>(ParamType)) { 2836 if (!PointeeType.getQualifiers() && 2837 isa<TemplateTypeParmType>(PointeeType) && 2838 Arg->Classify(S.Context).isLValue() && 2839 Arg->getType() != S.Context.OverloadTy && 2840 Arg->getType() != S.Context.BoundMemberTy) 2841 ArgType = S.Context.getLValueReferenceType(ArgType); 2842 } 2843 2844 // [...] If P is a reference type, the type referred to by P is used 2845 // for type deduction. 2846 ParamType = PointeeType; 2847 } 2848 2849 // Overload sets usually make this parameter an undeduced 2850 // context, but there are sometimes special circumstances. 2851 if (ArgType == S.Context.OverloadTy) { 2852 ArgType = ResolveOverloadForDeduction(S, TemplateParams, 2853 Arg, ParamType, 2854 ParamRefType != 0); 2855 if (ArgType.isNull()) 2856 return true; 2857 } 2858 2859 if (ParamRefType) { 2860 // C++0x [temp.deduct.call]p3: 2861 // [...] If P is of the form T&&, where T is a template parameter, and 2862 // the argument is an lvalue, the type A& is used in place of A for 2863 // type deduction. 2864 if (ParamRefType->isRValueReferenceType() && 2865 ParamRefType->getAs<TemplateTypeParmType>() && 2866 Arg->isLValue()) 2867 ArgType = S.Context.getLValueReferenceType(ArgType); 2868 } else { 2869 // C++ [temp.deduct.call]p2: 2870 // If P is not a reference type: 2871 // - If A is an array type, the pointer type produced by the 2872 // array-to-pointer standard conversion (4.2) is used in place of 2873 // A for type deduction; otherwise, 2874 if (ArgType->isArrayType()) 2875 ArgType = S.Context.getArrayDecayedType(ArgType); 2876 // - If A is a function type, the pointer type produced by the 2877 // function-to-pointer standard conversion (4.3) is used in place 2878 // of A for type deduction; otherwise, 2879 else if (ArgType->isFunctionType()) 2880 ArgType = S.Context.getPointerType(ArgType); 2881 else { 2882 // - If A is a cv-qualified type, the top level cv-qualifiers of A's 2883 // type are ignored for type deduction. 2884 ArgType = ArgType.getUnqualifiedType(); 2885 } 2886 } 2887 2888 // C++0x [temp.deduct.call]p4: 2889 // In general, the deduction process attempts to find template argument 2890 // values that will make the deduced A identical to A (after the type A 2891 // is transformed as described above). [...] 2892 TDF = TDF_SkipNonDependent; 2893 2894 // - If the original P is a reference type, the deduced A (i.e., the 2895 // type referred to by the reference) can be more cv-qualified than 2896 // the transformed A. 2897 if (ParamRefType) 2898 TDF |= TDF_ParamWithReferenceType; 2899 // - The transformed A can be another pointer or pointer to member 2900 // type that can be converted to the deduced A via a qualification 2901 // conversion (4.4). 2902 if (ArgType->isPointerType() || ArgType->isMemberPointerType() || 2903 ArgType->isObjCObjectPointerType()) 2904 TDF |= TDF_IgnoreQualifiers; 2905 // - If P is a class and P has the form simple-template-id, then the 2906 // transformed A can be a derived class of the deduced A. Likewise, 2907 // if P is a pointer to a class of the form simple-template-id, the 2908 // transformed A can be a pointer to a derived class pointed to by 2909 // the deduced A. 2910 if (isSimpleTemplateIdType(ParamType) || 2911 (isa<PointerType>(ParamType) && 2912 isSimpleTemplateIdType( 2913 ParamType->getAs<PointerType>()->getPointeeType()))) 2914 TDF |= TDF_DerivedClass; 2915 2916 return false; 2917} 2918 2919static bool hasDeducibleTemplateParameters(Sema &S, 2920 FunctionTemplateDecl *FunctionTemplate, 2921 QualType T); 2922 2923/// \brief Perform template argument deduction by matching a parameter type 2924/// against a single expression, where the expression is an element of 2925/// an initializer list that was originally matched against the argument 2926/// type. 2927static Sema::TemplateDeductionResult 2928DeduceTemplateArgumentByListElement(Sema &S, 2929 TemplateParameterList *TemplateParams, 2930 QualType ParamType, Expr *Arg, 2931 TemplateDeductionInfo &Info, 2932 SmallVectorImpl<DeducedTemplateArgument> &Deduced, 2933 unsigned TDF) { 2934 // Handle the case where an init list contains another init list as the 2935 // element. 2936 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 2937 QualType X; 2938 if (!S.isStdInitializerList(ParamType.getNonReferenceType(), &X)) 2939 return Sema::TDK_Success; // Just ignore this expression. 2940 2941 // Recurse down into the init list. 2942 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 2943 if (Sema::TemplateDeductionResult Result = 2944 DeduceTemplateArgumentByListElement(S, TemplateParams, X, 2945 ILE->getInit(i), 2946 Info, Deduced, TDF)) 2947 return Result; 2948 } 2949 return Sema::TDK_Success; 2950 } 2951 2952 // For all other cases, just match by type. 2953 QualType ArgType = Arg->getType(); 2954 if (AdjustFunctionParmAndArgTypesForDeduction(S, TemplateParams, ParamType, 2955 ArgType, Arg, TDF)) 2956 return Sema::TDK_FailedOverloadResolution; 2957 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType, 2958 ArgType, Info, Deduced, TDF); 2959} 2960 2961/// \brief Perform template argument deduction from a function call 2962/// (C++ [temp.deduct.call]). 2963/// 2964/// \param FunctionTemplate the function template for which we are performing 2965/// template argument deduction. 2966/// 2967/// \param ExplicitTemplateArguments the explicit template arguments provided 2968/// for this call. 2969/// 2970/// \param Args the function call arguments 2971/// 2972/// \param NumArgs the number of arguments in Args 2973/// 2974/// \param Name the name of the function being called. This is only significant 2975/// when the function template is a conversion function template, in which 2976/// case this routine will also perform template argument deduction based on 2977/// the function to which 2978/// 2979/// \param Specialization if template argument deduction was successful, 2980/// this will be set to the function template specialization produced by 2981/// template argument deduction. 2982/// 2983/// \param Info the argument will be updated to provide additional information 2984/// about template argument deduction. 2985/// 2986/// \returns the result of template argument deduction. 2987Sema::TemplateDeductionResult 2988Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 2989 TemplateArgumentListInfo *ExplicitTemplateArgs, 2990 llvm::ArrayRef<Expr *> Args, 2991 FunctionDecl *&Specialization, 2992 TemplateDeductionInfo &Info) { 2993 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2994 2995 // C++ [temp.deduct.call]p1: 2996 // Template argument deduction is done by comparing each function template 2997 // parameter type (call it P) with the type of the corresponding argument 2998 // of the call (call it A) as described below. 2999 unsigned CheckArgs = Args.size(); 3000 if (Args.size() < Function->getMinRequiredArguments()) 3001 return TDK_TooFewArguments; 3002 else if (Args.size() > Function->getNumParams()) { 3003 const FunctionProtoType *Proto 3004 = Function->getType()->getAs<FunctionProtoType>(); 3005 if (Proto->isTemplateVariadic()) 3006 /* Do nothing */; 3007 else if (Proto->isVariadic()) 3008 CheckArgs = Function->getNumParams(); 3009 else 3010 return TDK_TooManyArguments; 3011 } 3012 3013 // The types of the parameters from which we will perform template argument 3014 // deduction. 3015 LocalInstantiationScope InstScope(*this); 3016 TemplateParameterList *TemplateParams 3017 = FunctionTemplate->getTemplateParameters(); 3018 SmallVector<DeducedTemplateArgument, 4> Deduced; 3019 SmallVector<QualType, 4> ParamTypes; 3020 unsigned NumExplicitlySpecified = 0; 3021 if (ExplicitTemplateArgs) { 3022 TemplateDeductionResult Result = 3023 SubstituteExplicitTemplateArguments(FunctionTemplate, 3024 *ExplicitTemplateArgs, 3025 Deduced, 3026 ParamTypes, 3027 0, 3028 Info); 3029 if (Result) 3030 return Result; 3031 3032 NumExplicitlySpecified = Deduced.size(); 3033 } else { 3034 // Just fill in the parameter types from the function declaration. 3035 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 3036 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 3037 } 3038 3039 // Deduce template arguments from the function parameters. 3040 Deduced.resize(TemplateParams->size()); 3041 unsigned ArgIdx = 0; 3042 SmallVector<OriginalCallArg, 4> OriginalCallArgs; 3043 for (unsigned ParamIdx = 0, NumParams = ParamTypes.size(); 3044 ParamIdx != NumParams; ++ParamIdx) { 3045 QualType OrigParamType = ParamTypes[ParamIdx]; 3046 QualType ParamType = OrigParamType; 3047 3048 const PackExpansionType *ParamExpansion 3049 = dyn_cast<PackExpansionType>(ParamType); 3050 if (!ParamExpansion) { 3051 // Simple case: matching a function parameter to a function argument. 3052 if (ArgIdx >= CheckArgs) 3053 break; 3054 3055 Expr *Arg = Args[ArgIdx++]; 3056 QualType ArgType = Arg->getType(); 3057 3058 unsigned TDF = 0; 3059 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams, 3060 ParamType, ArgType, Arg, 3061 TDF)) 3062 continue; 3063 3064 // If we have nothing to deduce, we're done. 3065 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 3066 continue; 3067 3068 // If the argument is an initializer list ... 3069 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 3070 // ... then the parameter is an undeduced context, unless the parameter 3071 // type is (reference to cv) std::initializer_list<P'>, in which case 3072 // deduction is done for each element of the initializer list, and the 3073 // result is the deduced type if it's the same for all elements. 3074 QualType X; 3075 // Removing references was already done. 3076 if (!isStdInitializerList(ParamType, &X)) 3077 continue; 3078 3079 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 3080 if (TemplateDeductionResult Result = 3081 DeduceTemplateArgumentByListElement(*this, TemplateParams, X, 3082 ILE->getInit(i), 3083 Info, Deduced, TDF)) 3084 return Result; 3085 } 3086 // Don't track the argument type, since an initializer list has none. 3087 continue; 3088 } 3089 3090 // Keep track of the argument type and corresponding parameter index, 3091 // so we can check for compatibility between the deduced A and A. 3092 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx-1, 3093 ArgType)); 3094 3095 if (TemplateDeductionResult Result 3096 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3097 ParamType, ArgType, 3098 Info, Deduced, TDF)) 3099 return Result; 3100 3101 continue; 3102 } 3103 3104 // C++0x [temp.deduct.call]p1: 3105 // For a function parameter pack that occurs at the end of the 3106 // parameter-declaration-list, the type A of each remaining argument of 3107 // the call is compared with the type P of the declarator-id of the 3108 // function parameter pack. Each comparison deduces template arguments 3109 // for subsequent positions in the template parameter packs expanded by 3110 // the function parameter pack. For a function parameter pack that does 3111 // not occur at the end of the parameter-declaration-list, the type of 3112 // the parameter pack is a non-deduced context. 3113 if (ParamIdx + 1 < NumParams) 3114 break; 3115 3116 QualType ParamPattern = ParamExpansion->getPattern(); 3117 SmallVector<unsigned, 2> PackIndices; 3118 { 3119 llvm::SmallBitVector SawIndices(TemplateParams->size()); 3120 SmallVector<UnexpandedParameterPack, 2> Unexpanded; 3121 collectUnexpandedParameterPacks(ParamPattern, Unexpanded); 3122 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) { 3123 unsigned Depth, Index; 3124 llvm::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]); 3125 if (Depth == 0 && !SawIndices[Index]) { 3126 SawIndices[Index] = true; 3127 PackIndices.push_back(Index); 3128 } 3129 } 3130 } 3131 assert(!PackIndices.empty() && "Pack expansion without unexpanded packs?"); 3132 3133 // Keep track of the deduced template arguments for each parameter pack 3134 // expanded by this pack expansion (the outer index) and for each 3135 // template argument (the inner SmallVectors). 3136 SmallVector<SmallVector<DeducedTemplateArgument, 4>, 2> 3137 NewlyDeducedPacks(PackIndices.size()); 3138 SmallVector<DeducedTemplateArgument, 2> 3139 SavedPacks(PackIndices.size()); 3140 PrepareArgumentPackDeduction(*this, Deduced, PackIndices, SavedPacks, 3141 NewlyDeducedPacks); 3142 bool HasAnyArguments = false; 3143 for (; ArgIdx < Args.size(); ++ArgIdx) { 3144 HasAnyArguments = true; 3145 3146 QualType OrigParamType = ParamPattern; 3147 ParamType = OrigParamType; 3148 Expr *Arg = Args[ArgIdx]; 3149 QualType ArgType = Arg->getType(); 3150 3151 unsigned TDF = 0; 3152 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams, 3153 ParamType, ArgType, Arg, 3154 TDF)) { 3155 // We can't actually perform any deduction for this argument, so stop 3156 // deduction at this point. 3157 ++ArgIdx; 3158 break; 3159 } 3160 3161 // As above, initializer lists need special handling. 3162 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) { 3163 QualType X; 3164 if (!isStdInitializerList(ParamType, &X)) { 3165 ++ArgIdx; 3166 break; 3167 } 3168 3169 for (unsigned i = 0, e = ILE->getNumInits(); i < e; ++i) { 3170 if (TemplateDeductionResult Result = 3171 DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, X, 3172 ILE->getInit(i)->getType(), 3173 Info, Deduced, TDF)) 3174 return Result; 3175 } 3176 } else { 3177 3178 // Keep track of the argument type and corresponding argument index, 3179 // so we can check for compatibility between the deduced A and A. 3180 if (hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType)) 3181 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx, 3182 ArgType)); 3183 3184 if (TemplateDeductionResult Result 3185 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3186 ParamType, ArgType, Info, 3187 Deduced, TDF)) 3188 return Result; 3189 } 3190 3191 // Capture the deduced template arguments for each parameter pack expanded 3192 // by this pack expansion, add them to the list of arguments we've deduced 3193 // for that pack, then clear out the deduced argument. 3194 for (unsigned I = 0, N = PackIndices.size(); I != N; ++I) { 3195 DeducedTemplateArgument &DeducedArg = Deduced[PackIndices[I]]; 3196 if (!DeducedArg.isNull()) { 3197 NewlyDeducedPacks[I].push_back(DeducedArg); 3198 DeducedArg = DeducedTemplateArgument(); 3199 } 3200 } 3201 } 3202 3203 // Build argument packs for each of the parameter packs expanded by this 3204 // pack expansion. 3205 if (Sema::TemplateDeductionResult Result 3206 = FinishArgumentPackDeduction(*this, TemplateParams, HasAnyArguments, 3207 Deduced, PackIndices, SavedPacks, 3208 NewlyDeducedPacks, Info)) 3209 return Result; 3210 3211 // After we've matching against a parameter pack, we're done. 3212 break; 3213 } 3214 3215 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 3216 NumExplicitlySpecified, 3217 Specialization, Info, &OriginalCallArgs); 3218} 3219 3220/// \brief Deduce template arguments when taking the address of a function 3221/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 3222/// a template. 3223/// 3224/// \param FunctionTemplate the function template for which we are performing 3225/// template argument deduction. 3226/// 3227/// \param ExplicitTemplateArguments the explicitly-specified template 3228/// arguments. 3229/// 3230/// \param ArgFunctionType the function type that will be used as the 3231/// "argument" type (A) when performing template argument deduction from the 3232/// function template's function type. This type may be NULL, if there is no 3233/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 3234/// 3235/// \param Specialization if template argument deduction was successful, 3236/// this will be set to the function template specialization produced by 3237/// template argument deduction. 3238/// 3239/// \param Info the argument will be updated to provide additional information 3240/// about template argument deduction. 3241/// 3242/// \returns the result of template argument deduction. 3243Sema::TemplateDeductionResult 3244Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3245 TemplateArgumentListInfo *ExplicitTemplateArgs, 3246 QualType ArgFunctionType, 3247 FunctionDecl *&Specialization, 3248 TemplateDeductionInfo &Info) { 3249 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 3250 TemplateParameterList *TemplateParams 3251 = FunctionTemplate->getTemplateParameters(); 3252 QualType FunctionType = Function->getType(); 3253 3254 // Substitute any explicit template arguments. 3255 LocalInstantiationScope InstScope(*this); 3256 SmallVector<DeducedTemplateArgument, 4> Deduced; 3257 unsigned NumExplicitlySpecified = 0; 3258 SmallVector<QualType, 4> ParamTypes; 3259 if (ExplicitTemplateArgs) { 3260 if (TemplateDeductionResult Result 3261 = SubstituteExplicitTemplateArguments(FunctionTemplate, 3262 *ExplicitTemplateArgs, 3263 Deduced, ParamTypes, 3264 &FunctionType, Info)) 3265 return Result; 3266 3267 NumExplicitlySpecified = Deduced.size(); 3268 } 3269 3270 // Unevaluated SFINAE context. 3271 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 3272 SFINAETrap Trap(*this); 3273 3274 Deduced.resize(TemplateParams->size()); 3275 3276 if (!ArgFunctionType.isNull()) { 3277 // Deduce template arguments from the function type. 3278 if (TemplateDeductionResult Result 3279 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3280 FunctionType, ArgFunctionType, Info, 3281 Deduced, TDF_TopLevelParameterTypeList)) 3282 return Result; 3283 } 3284 3285 if (TemplateDeductionResult Result 3286 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 3287 NumExplicitlySpecified, 3288 Specialization, Info)) 3289 return Result; 3290 3291 // If the requested function type does not match the actual type of the 3292 // specialization, template argument deduction fails. 3293 if (!ArgFunctionType.isNull() && 3294 !Context.hasSameType(ArgFunctionType, Specialization->getType())) 3295 return TDK_NonDeducedMismatch; 3296 3297 return TDK_Success; 3298} 3299 3300/// \brief Deduce template arguments for a templated conversion 3301/// function (C++ [temp.deduct.conv]) and, if successful, produce a 3302/// conversion function template specialization. 3303Sema::TemplateDeductionResult 3304Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3305 QualType ToType, 3306 CXXConversionDecl *&Specialization, 3307 TemplateDeductionInfo &Info) { 3308 CXXConversionDecl *Conv 3309 = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()); 3310 QualType FromType = Conv->getConversionType(); 3311 3312 // Canonicalize the types for deduction. 3313 QualType P = Context.getCanonicalType(FromType); 3314 QualType A = Context.getCanonicalType(ToType); 3315 3316 // C++0x [temp.deduct.conv]p2: 3317 // If P is a reference type, the type referred to by P is used for 3318 // type deduction. 3319 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 3320 P = PRef->getPointeeType(); 3321 3322 // C++0x [temp.deduct.conv]p4: 3323 // [...] If A is a reference type, the type referred to by A is used 3324 // for type deduction. 3325 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 3326 A = ARef->getPointeeType().getUnqualifiedType(); 3327 // C++ [temp.deduct.conv]p3: 3328 // 3329 // If A is not a reference type: 3330 else { 3331 assert(!A->isReferenceType() && "Reference types were handled above"); 3332 3333 // - If P is an array type, the pointer type produced by the 3334 // array-to-pointer standard conversion (4.2) is used in place 3335 // of P for type deduction; otherwise, 3336 if (P->isArrayType()) 3337 P = Context.getArrayDecayedType(P); 3338 // - If P is a function type, the pointer type produced by the 3339 // function-to-pointer standard conversion (4.3) is used in 3340 // place of P for type deduction; otherwise, 3341 else if (P->isFunctionType()) 3342 P = Context.getPointerType(P); 3343 // - If P is a cv-qualified type, the top level cv-qualifiers of 3344 // P's type are ignored for type deduction. 3345 else 3346 P = P.getUnqualifiedType(); 3347 3348 // C++0x [temp.deduct.conv]p4: 3349 // If A is a cv-qualified type, the top level cv-qualifiers of A's 3350 // type are ignored for type deduction. If A is a reference type, the type 3351 // referred to by A is used for type deduction. 3352 A = A.getUnqualifiedType(); 3353 } 3354 3355 // Unevaluated SFINAE context. 3356 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated); 3357 SFINAETrap Trap(*this); 3358 3359 // C++ [temp.deduct.conv]p1: 3360 // Template argument deduction is done by comparing the return 3361 // type of the template conversion function (call it P) with the 3362 // type that is required as the result of the conversion (call it 3363 // A) as described in 14.8.2.4. 3364 TemplateParameterList *TemplateParams 3365 = FunctionTemplate->getTemplateParameters(); 3366 SmallVector<DeducedTemplateArgument, 4> Deduced; 3367 Deduced.resize(TemplateParams->size()); 3368 3369 // C++0x [temp.deduct.conv]p4: 3370 // In general, the deduction process attempts to find template 3371 // argument values that will make the deduced A identical to 3372 // A. However, there are two cases that allow a difference: 3373 unsigned TDF = 0; 3374 // - If the original A is a reference type, A can be more 3375 // cv-qualified than the deduced A (i.e., the type referred to 3376 // by the reference) 3377 if (ToType->isReferenceType()) 3378 TDF |= TDF_ParamWithReferenceType; 3379 // - The deduced A can be another pointer or pointer to member 3380 // type that can be converted to A via a qualification 3381 // conversion. 3382 // 3383 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 3384 // both P and A are pointers or member pointers. In this case, we 3385 // just ignore cv-qualifiers completely). 3386 if ((P->isPointerType() && A->isPointerType()) || 3387 (P->isMemberPointerType() && A->isMemberPointerType())) 3388 TDF |= TDF_IgnoreQualifiers; 3389 if (TemplateDeductionResult Result 3390 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams, 3391 P, A, Info, Deduced, TDF)) 3392 return Result; 3393 3394 // Finish template argument deduction. 3395 LocalInstantiationScope InstScope(*this); 3396 FunctionDecl *Spec = 0; 3397 TemplateDeductionResult Result 3398 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, 3399 Info); 3400 Specialization = cast_or_null<CXXConversionDecl>(Spec); 3401 return Result; 3402} 3403 3404/// \brief Deduce template arguments for a function template when there is 3405/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 3406/// 3407/// \param FunctionTemplate the function template for which we are performing 3408/// template argument deduction. 3409/// 3410/// \param ExplicitTemplateArguments the explicitly-specified template 3411/// arguments. 3412/// 3413/// \param Specialization if template argument deduction was successful, 3414/// this will be set to the function template specialization produced by 3415/// template argument deduction. 3416/// 3417/// \param Info the argument will be updated to provide additional information 3418/// about template argument deduction. 3419/// 3420/// \returns the result of template argument deduction. 3421Sema::TemplateDeductionResult 3422Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 3423 TemplateArgumentListInfo *ExplicitTemplateArgs, 3424 FunctionDecl *&Specialization, 3425 TemplateDeductionInfo &Info) { 3426 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3427 QualType(), Specialization, Info); 3428} 3429 3430namespace { 3431 /// Substitute the 'auto' type specifier within a type for a given replacement 3432 /// type. 3433 class SubstituteAutoTransform : 3434 public TreeTransform<SubstituteAutoTransform> { 3435 QualType Replacement; 3436 public: 3437 SubstituteAutoTransform(Sema &SemaRef, QualType Replacement) : 3438 TreeTransform<SubstituteAutoTransform>(SemaRef), Replacement(Replacement) { 3439 } 3440 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) { 3441 // If we're building the type pattern to deduce against, don't wrap the 3442 // substituted type in an AutoType. Certain template deduction rules 3443 // apply only when a template type parameter appears directly (and not if 3444 // the parameter is found through desugaring). For instance: 3445 // auto &&lref = lvalue; 3446 // must transform into "rvalue reference to T" not "rvalue reference to 3447 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply. 3448 if (isa<TemplateTypeParmType>(Replacement)) { 3449 QualType Result = Replacement; 3450 TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result); 3451 NewTL.setNameLoc(TL.getNameLoc()); 3452 return Result; 3453 } else { 3454 QualType Result = RebuildAutoType(Replacement); 3455 AutoTypeLoc NewTL = TLB.push<AutoTypeLoc>(Result); 3456 NewTL.setNameLoc(TL.getNameLoc()); 3457 return Result; 3458 } 3459 } 3460 3461 ExprResult TransformLambdaExpr(LambdaExpr *E) { 3462 // Lambdas never need to be transformed. 3463 return E; 3464 } 3465 }; 3466} 3467 3468/// \brief Deduce the type for an auto type-specifier (C++0x [dcl.spec.auto]p6) 3469/// 3470/// \param Type the type pattern using the auto type-specifier. 3471/// 3472/// \param Init the initializer for the variable whose type is to be deduced. 3473/// 3474/// \param Result if type deduction was successful, this will be set to the 3475/// deduced type. This may still contain undeduced autos if the type is 3476/// dependent. This will be set to null if deduction succeeded, but auto 3477/// substitution failed; the appropriate diagnostic will already have been 3478/// produced in that case. 3479Sema::DeduceAutoResult 3480Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, 3481 TypeSourceInfo *&Result) { 3482 if (Init->getType()->isNonOverloadPlaceholderType()) { 3483 ExprResult result = CheckPlaceholderExpr(Init); 3484 if (result.isInvalid()) return DAR_FailedAlreadyDiagnosed; 3485 Init = result.take(); 3486 } 3487 3488 if (Init->isTypeDependent()) { 3489 Result = Type; 3490 return DAR_Succeeded; 3491 } 3492 3493 SourceLocation Loc = Init->getExprLoc(); 3494 3495 LocalInstantiationScope InstScope(*this); 3496 3497 // Build template<class TemplParam> void Func(FuncParam); 3498 TemplateTypeParmDecl *TemplParam = 3499 TemplateTypeParmDecl::Create(Context, 0, SourceLocation(), Loc, 0, 0, 0, 3500 false, false); 3501 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0); 3502 NamedDecl *TemplParamPtr = TemplParam; 3503 FixedSizeTemplateParameterList<1> TemplateParams(Loc, Loc, &TemplParamPtr, 3504 Loc); 3505 3506 TypeSourceInfo *FuncParamInfo = 3507 SubstituteAutoTransform(*this, TemplArg).TransformType(Type); 3508 assert(FuncParamInfo && "substituting template parameter for 'auto' failed"); 3509 QualType FuncParam = FuncParamInfo->getType(); 3510 3511 // Deduce type of TemplParam in Func(Init) 3512 SmallVector<DeducedTemplateArgument, 1> Deduced; 3513 Deduced.resize(1); 3514 QualType InitType = Init->getType(); 3515 unsigned TDF = 0; 3516 3517 TemplateDeductionInfo Info(Context, Loc); 3518 3519 InitListExpr * InitList = dyn_cast<InitListExpr>(Init); 3520 if (InitList) { 3521 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) { 3522 if (DeduceTemplateArgumentByListElement(*this, &TemplateParams, 3523 TemplArg, 3524 InitList->getInit(i), 3525 Info, Deduced, TDF)) 3526 return DAR_Failed; 3527 } 3528 } else { 3529 if (AdjustFunctionParmAndArgTypesForDeduction(*this, &TemplateParams, 3530 FuncParam, InitType, Init, 3531 TDF)) 3532 return DAR_Failed; 3533 3534 if (DeduceTemplateArgumentsByTypeMatch(*this, &TemplateParams, FuncParam, 3535 InitType, Info, Deduced, TDF)) 3536 return DAR_Failed; 3537 } 3538 3539 QualType DeducedType = Deduced[0].getAsType(); 3540 if (DeducedType.isNull()) 3541 return DAR_Failed; 3542 3543 if (InitList) { 3544 DeducedType = BuildStdInitializerList(DeducedType, Loc); 3545 if (DeducedType.isNull()) 3546 return DAR_FailedAlreadyDiagnosed; 3547 } 3548 3549 Result = SubstituteAutoTransform(*this, DeducedType).TransformType(Type); 3550 3551 // Check that the deduced argument type is compatible with the original 3552 // argument type per C++ [temp.deduct.call]p4. 3553 if (!InitList && Result && 3554 CheckOriginalCallArgDeduction(*this, 3555 Sema::OriginalCallArg(FuncParam,0,InitType), 3556 Result->getType())) { 3557 Result = 0; 3558 return DAR_Failed; 3559 } 3560 3561 return DAR_Succeeded; 3562} 3563 3564void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) { 3565 if (isa<InitListExpr>(Init)) 3566 Diag(VDecl->getLocation(), 3567 diag::err_auto_var_deduction_failure_from_init_list) 3568 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange(); 3569 else 3570 Diag(VDecl->getLocation(), diag::err_auto_var_deduction_failure) 3571 << VDecl->getDeclName() << VDecl->getType() << Init->getType() 3572 << Init->getSourceRange(); 3573} 3574 3575static void 3576MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 3577 bool OnlyDeduced, 3578 unsigned Level, 3579 llvm::SmallBitVector &Deduced); 3580 3581/// \brief If this is a non-static member function, 3582static void MaybeAddImplicitObjectParameterType(ASTContext &Context, 3583 CXXMethodDecl *Method, 3584 SmallVectorImpl<QualType> &ArgTypes) { 3585 if (Method->isStatic()) 3586 return; 3587 3588 // C++ [over.match.funcs]p4: 3589 // 3590 // For non-static member functions, the type of the implicit 3591 // object parameter is 3592 // - "lvalue reference to cv X" for functions declared without a 3593 // ref-qualifier or with the & ref-qualifier 3594 // - "rvalue reference to cv X" for functions declared with the 3595 // && ref-qualifier 3596 // 3597 // FIXME: We don't have ref-qualifiers yet, so we don't do that part. 3598 QualType ArgTy = Context.getTypeDeclType(Method->getParent()); 3599 ArgTy = Context.getQualifiedType(ArgTy, 3600 Qualifiers::fromCVRMask(Method->getTypeQualifiers())); 3601 ArgTy = Context.getLValueReferenceType(ArgTy); 3602 ArgTypes.push_back(ArgTy); 3603} 3604 3605/// \brief Determine whether the function template \p FT1 is at least as 3606/// specialized as \p FT2. 3607static bool isAtLeastAsSpecializedAs(Sema &S, 3608 SourceLocation Loc, 3609 FunctionTemplateDecl *FT1, 3610 FunctionTemplateDecl *FT2, 3611 TemplatePartialOrderingContext TPOC, 3612 unsigned NumCallArguments, 3613 SmallVectorImpl<RefParamPartialOrderingComparison> *RefParamComparisons) { 3614 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 3615 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 3616 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 3617 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 3618 3619 assert(Proto1 && Proto2 && "Function templates must have prototypes"); 3620 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 3621 SmallVector<DeducedTemplateArgument, 4> Deduced; 3622 Deduced.resize(TemplateParams->size()); 3623 3624 // C++0x [temp.deduct.partial]p3: 3625 // The types used to determine the ordering depend on the context in which 3626 // the partial ordering is done: 3627 TemplateDeductionInfo Info(S.Context, Loc); 3628 CXXMethodDecl *Method1 = 0; 3629 CXXMethodDecl *Method2 = 0; 3630 bool IsNonStatic2 = false; 3631 bool IsNonStatic1 = false; 3632 unsigned Skip2 = 0; 3633 switch (TPOC) { 3634 case TPOC_Call: { 3635 // - In the context of a function call, the function parameter types are 3636 // used. 3637 Method1 = dyn_cast<CXXMethodDecl>(FD1); 3638 Method2 = dyn_cast<CXXMethodDecl>(FD2); 3639 IsNonStatic1 = Method1 && !Method1->isStatic(); 3640 IsNonStatic2 = Method2 && !Method2->isStatic(); 3641 3642 // C++0x [temp.func.order]p3: 3643 // [...] If only one of the function templates is a non-static 3644 // member, that function template is considered to have a new 3645 // first parameter inserted in its function parameter list. The 3646 // new parameter is of type "reference to cv A," where cv are 3647 // the cv-qualifiers of the function template (if any) and A is 3648 // the class of which the function template is a member. 3649 // 3650 // C++98/03 doesn't have this provision, so instead we drop the 3651 // first argument of the free function or static member, which 3652 // seems to match existing practice. 3653 SmallVector<QualType, 4> Args1; 3654 unsigned Skip1 = !S.getLangOpts().CPlusPlus0x && 3655 IsNonStatic2 && !IsNonStatic1; 3656 if (S.getLangOpts().CPlusPlus0x && IsNonStatic1 && !IsNonStatic2) 3657 MaybeAddImplicitObjectParameterType(S.Context, Method1, Args1); 3658 Args1.insert(Args1.end(), 3659 Proto1->arg_type_begin() + Skip1, Proto1->arg_type_end()); 3660 3661 SmallVector<QualType, 4> Args2; 3662 Skip2 = !S.getLangOpts().CPlusPlus0x && 3663 IsNonStatic1 && !IsNonStatic2; 3664 if (S.getLangOpts().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) 3665 MaybeAddImplicitObjectParameterType(S.Context, Method2, Args2); 3666 Args2.insert(Args2.end(), 3667 Proto2->arg_type_begin() + Skip2, Proto2->arg_type_end()); 3668 3669 // C++ [temp.func.order]p5: 3670 // The presence of unused ellipsis and default arguments has no effect on 3671 // the partial ordering of function templates. 3672 if (Args1.size() > NumCallArguments) 3673 Args1.resize(NumCallArguments); 3674 if (Args2.size() > NumCallArguments) 3675 Args2.resize(NumCallArguments); 3676 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(), 3677 Args1.data(), Args1.size(), Info, Deduced, 3678 TDF_None, /*PartialOrdering=*/true, 3679 RefParamComparisons)) 3680 return false; 3681 3682 break; 3683 } 3684 3685 case TPOC_Conversion: 3686 // - In the context of a call to a conversion operator, the return types 3687 // of the conversion function templates are used. 3688 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 3689 Proto2->getResultType(), 3690 Proto1->getResultType(), 3691 Info, Deduced, TDF_None, 3692 /*PartialOrdering=*/true, 3693 RefParamComparisons)) 3694 return false; 3695 break; 3696 3697 case TPOC_Other: 3698 // - In other contexts (14.6.6.2) the function template's function type 3699 // is used. 3700 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, 3701 FD2->getType(), FD1->getType(), 3702 Info, Deduced, TDF_None, 3703 /*PartialOrdering=*/true, 3704 RefParamComparisons)) 3705 return false; 3706 break; 3707 } 3708 3709 // C++0x [temp.deduct.partial]p11: 3710 // In most cases, all template parameters must have values in order for 3711 // deduction to succeed, but for partial ordering purposes a template 3712 // parameter may remain without a value provided it is not used in the 3713 // types being used for partial ordering. [ Note: a template parameter used 3714 // in a non-deduced context is considered used. -end note] 3715 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 3716 for (; ArgIdx != NumArgs; ++ArgIdx) 3717 if (Deduced[ArgIdx].isNull()) 3718 break; 3719 3720 if (ArgIdx == NumArgs) { 3721 // All template arguments were deduced. FT1 is at least as specialized 3722 // as FT2. 3723 return true; 3724 } 3725 3726 // Figure out which template parameters were used. 3727 llvm::SmallBitVector UsedParameters(TemplateParams->size()); 3728 switch (TPOC) { 3729 case TPOC_Call: { 3730 unsigned NumParams = std::min(NumCallArguments, 3731 std::min(Proto1->getNumArgs(), 3732 Proto2->getNumArgs())); 3733 if (S.getLangOpts().CPlusPlus0x && IsNonStatic2 && !IsNonStatic1) 3734 ::MarkUsedTemplateParameters(S.Context, Method2->getThisType(S.Context), 3735 false, 3736 TemplateParams->getDepth(), UsedParameters); 3737 for (unsigned I = Skip2; I < NumParams; ++I) 3738 ::MarkUsedTemplateParameters(S.Context, Proto2->getArgType(I), false, 3739 TemplateParams->getDepth(), 3740 UsedParameters); 3741 break; 3742 } 3743 3744 case TPOC_Conversion: 3745 ::MarkUsedTemplateParameters(S.Context, Proto2->getResultType(), false, 3746 TemplateParams->getDepth(), 3747 UsedParameters); 3748 break; 3749 3750 case TPOC_Other: 3751 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false, 3752 TemplateParams->getDepth(), 3753 UsedParameters); 3754 break; 3755 } 3756 3757 for (; ArgIdx != NumArgs; ++ArgIdx) 3758 // If this argument had no value deduced but was used in one of the types 3759 // used for partial ordering, then deduction fails. 3760 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 3761 return false; 3762 3763 return true; 3764} 3765 3766/// \brief Determine whether this a function template whose parameter-type-list 3767/// ends with a function parameter pack. 3768static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) { 3769 FunctionDecl *Function = FunTmpl->getTemplatedDecl(); 3770 unsigned NumParams = Function->getNumParams(); 3771 if (NumParams == 0) 3772 return false; 3773 3774 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1); 3775 if (!Last->isParameterPack()) 3776 return false; 3777 3778 // Make sure that no previous parameter is a parameter pack. 3779 while (--NumParams > 0) { 3780 if (Function->getParamDecl(NumParams - 1)->isParameterPack()) 3781 return false; 3782 } 3783 3784 return true; 3785} 3786 3787/// \brief Returns the more specialized function template according 3788/// to the rules of function template partial ordering (C++ [temp.func.order]). 3789/// 3790/// \param FT1 the first function template 3791/// 3792/// \param FT2 the second function template 3793/// 3794/// \param TPOC the context in which we are performing partial ordering of 3795/// function templates. 3796/// 3797/// \param NumCallArguments The number of arguments in a call, used only 3798/// when \c TPOC is \c TPOC_Call. 3799/// 3800/// \returns the more specialized function template. If neither 3801/// template is more specialized, returns NULL. 3802FunctionTemplateDecl * 3803Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 3804 FunctionTemplateDecl *FT2, 3805 SourceLocation Loc, 3806 TemplatePartialOrderingContext TPOC, 3807 unsigned NumCallArguments) { 3808 SmallVector<RefParamPartialOrderingComparison, 4> RefParamComparisons; 3809 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 3810 NumCallArguments, 0); 3811 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 3812 NumCallArguments, 3813 &RefParamComparisons); 3814 3815 if (Better1 != Better2) // We have a clear winner 3816 return Better1? FT1 : FT2; 3817 3818 if (!Better1 && !Better2) // Neither is better than the other 3819 return 0; 3820 3821 // C++0x [temp.deduct.partial]p10: 3822 // If for each type being considered a given template is at least as 3823 // specialized for all types and more specialized for some set of types and 3824 // the other template is not more specialized for any types or is not at 3825 // least as specialized for any types, then the given template is more 3826 // specialized than the other template. Otherwise, neither template is more 3827 // specialized than the other. 3828 Better1 = false; 3829 Better2 = false; 3830 for (unsigned I = 0, N = RefParamComparisons.size(); I != N; ++I) { 3831 // C++0x [temp.deduct.partial]p9: 3832 // If, for a given type, deduction succeeds in both directions (i.e., the 3833 // types are identical after the transformations above) and both P and A 3834 // were reference types (before being replaced with the type referred to 3835 // above): 3836 3837 // -- if the type from the argument template was an lvalue reference 3838 // and the type from the parameter template was not, the argument 3839 // type is considered to be more specialized than the other; 3840 // otherwise, 3841 if (!RefParamComparisons[I].ArgIsRvalueRef && 3842 RefParamComparisons[I].ParamIsRvalueRef) { 3843 Better2 = true; 3844 if (Better1) 3845 return 0; 3846 continue; 3847 } else if (!RefParamComparisons[I].ParamIsRvalueRef && 3848 RefParamComparisons[I].ArgIsRvalueRef) { 3849 Better1 = true; 3850 if (Better2) 3851 return 0; 3852 continue; 3853 } 3854 3855 // -- if the type from the argument template is more cv-qualified than 3856 // the type from the parameter template (as described above), the 3857 // argument type is considered to be more specialized than the 3858 // other; otherwise, 3859 switch (RefParamComparisons[I].Qualifiers) { 3860 case NeitherMoreQualified: 3861 break; 3862 3863 case ParamMoreQualified: 3864 Better1 = true; 3865 if (Better2) 3866 return 0; 3867 continue; 3868 3869 case ArgMoreQualified: 3870 Better2 = true; 3871 if (Better1) 3872 return 0; 3873 continue; 3874 } 3875 3876 // -- neither type is more specialized than the other. 3877 } 3878 3879 assert(!(Better1 && Better2) && "Should have broken out in the loop above"); 3880 if (Better1) 3881 return FT1; 3882 else if (Better2) 3883 return FT2; 3884 3885 // FIXME: This mimics what GCC implements, but doesn't match up with the 3886 // proposed resolution for core issue 692. This area needs to be sorted out, 3887 // but for now we attempt to maintain compatibility. 3888 bool Variadic1 = isVariadicFunctionTemplate(FT1); 3889 bool Variadic2 = isVariadicFunctionTemplate(FT2); 3890 if (Variadic1 != Variadic2) 3891 return Variadic1? FT2 : FT1; 3892 3893 return 0; 3894} 3895 3896/// \brief Determine if the two templates are equivalent. 3897static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 3898 if (T1 == T2) 3899 return true; 3900 3901 if (!T1 || !T2) 3902 return false; 3903 3904 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 3905} 3906 3907/// \brief Retrieve the most specialized of the given function template 3908/// specializations. 3909/// 3910/// \param SpecBegin the start iterator of the function template 3911/// specializations that we will be comparing. 3912/// 3913/// \param SpecEnd the end iterator of the function template 3914/// specializations, paired with \p SpecBegin. 3915/// 3916/// \param TPOC the partial ordering context to use to compare the function 3917/// template specializations. 3918/// 3919/// \param NumCallArguments The number of arguments in a call, used only 3920/// when \c TPOC is \c TPOC_Call. 3921/// 3922/// \param Loc the location where the ambiguity or no-specializations 3923/// diagnostic should occur. 3924/// 3925/// \param NoneDiag partial diagnostic used to diagnose cases where there are 3926/// no matching candidates. 3927/// 3928/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 3929/// occurs. 3930/// 3931/// \param CandidateDiag partial diagnostic used for each function template 3932/// specialization that is a candidate in the ambiguous ordering. One parameter 3933/// in this diagnostic should be unbound, which will correspond to the string 3934/// describing the template arguments for the function template specialization. 3935/// 3936/// \param Index if non-NULL and the result of this function is non-nULL, 3937/// receives the index corresponding to the resulting function template 3938/// specialization. 3939/// 3940/// \returns the most specialized function template specialization, if 3941/// found. Otherwise, returns SpecEnd. 3942/// 3943/// \todo FIXME: Consider passing in the "also-ran" candidates that failed 3944/// template argument deduction. 3945UnresolvedSetIterator 3946Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, 3947 UnresolvedSetIterator SpecEnd, 3948 TemplatePartialOrderingContext TPOC, 3949 unsigned NumCallArguments, 3950 SourceLocation Loc, 3951 const PartialDiagnostic &NoneDiag, 3952 const PartialDiagnostic &AmbigDiag, 3953 const PartialDiagnostic &CandidateDiag, 3954 bool Complain, 3955 QualType TargetType) { 3956 if (SpecBegin == SpecEnd) { 3957 if (Complain) 3958 Diag(Loc, NoneDiag); 3959 return SpecEnd; 3960 } 3961 3962 if (SpecBegin + 1 == SpecEnd) 3963 return SpecBegin; 3964 3965 // Find the function template that is better than all of the templates it 3966 // has been compared to. 3967 UnresolvedSetIterator Best = SpecBegin; 3968 FunctionTemplateDecl *BestTemplate 3969 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 3970 assert(BestTemplate && "Not a function template specialization?"); 3971 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 3972 FunctionTemplateDecl *Challenger 3973 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 3974 assert(Challenger && "Not a function template specialization?"); 3975 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 3976 Loc, TPOC, NumCallArguments), 3977 Challenger)) { 3978 Best = I; 3979 BestTemplate = Challenger; 3980 } 3981 } 3982 3983 // Make sure that the "best" function template is more specialized than all 3984 // of the others. 3985 bool Ambiguous = false; 3986 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 3987 FunctionTemplateDecl *Challenger 3988 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 3989 if (I != Best && 3990 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 3991 Loc, TPOC, NumCallArguments), 3992 BestTemplate)) { 3993 Ambiguous = true; 3994 break; 3995 } 3996 } 3997 3998 if (!Ambiguous) { 3999 // We found an answer. Return it. 4000 return Best; 4001 } 4002 4003 // Diagnose the ambiguity. 4004 if (Complain) 4005 Diag(Loc, AmbigDiag); 4006 4007 if (Complain) 4008 // FIXME: Can we order the candidates in some sane way? 4009 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 4010 PartialDiagnostic PD = CandidateDiag; 4011 PD << getTemplateArgumentBindingsText( 4012 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(), 4013 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs()); 4014 if (!TargetType.isNull()) 4015 HandleFunctionTypeMismatch(PD, cast<FunctionDecl>(*I)->getType(), 4016 TargetType); 4017 Diag((*I)->getLocation(), PD); 4018 } 4019 4020 return SpecEnd; 4021} 4022 4023/// \brief Returns the more specialized class template partial specialization 4024/// according to the rules of partial ordering of class template partial 4025/// specializations (C++ [temp.class.order]). 4026/// 4027/// \param PS1 the first class template partial specialization 4028/// 4029/// \param PS2 the second class template partial specialization 4030/// 4031/// \returns the more specialized class template partial specialization. If 4032/// neither partial specialization is more specialized, returns NULL. 4033ClassTemplatePartialSpecializationDecl * 4034Sema::getMoreSpecializedPartialSpecialization( 4035 ClassTemplatePartialSpecializationDecl *PS1, 4036 ClassTemplatePartialSpecializationDecl *PS2, 4037 SourceLocation Loc) { 4038 // C++ [temp.class.order]p1: 4039 // For two class template partial specializations, the first is at least as 4040 // specialized as the second if, given the following rewrite to two 4041 // function templates, the first function template is at least as 4042 // specialized as the second according to the ordering rules for function 4043 // templates (14.6.6.2): 4044 // - the first function template has the same template parameters as the 4045 // first partial specialization and has a single function parameter 4046 // whose type is a class template specialization with the template 4047 // arguments of the first partial specialization, and 4048 // - the second function template has the same template parameters as the 4049 // second partial specialization and has a single function parameter 4050 // whose type is a class template specialization with the template 4051 // arguments of the second partial specialization. 4052 // 4053 // Rather than synthesize function templates, we merely perform the 4054 // equivalent partial ordering by performing deduction directly on 4055 // the template arguments of the class template partial 4056 // specializations. This computation is slightly simpler than the 4057 // general problem of function template partial ordering, because 4058 // class template partial specializations are more constrained. We 4059 // know that every template parameter is deducible from the class 4060 // template partial specialization's template arguments, for 4061 // example. 4062 SmallVector<DeducedTemplateArgument, 4> Deduced; 4063 TemplateDeductionInfo Info(Context, Loc); 4064 4065 QualType PT1 = PS1->getInjectedSpecializationType(); 4066 QualType PT2 = PS2->getInjectedSpecializationType(); 4067 4068 // Determine whether PS1 is at least as specialized as PS2 4069 Deduced.resize(PS2->getTemplateParameters()->size()); 4070 bool Better1 = !DeduceTemplateArgumentsByTypeMatch(*this, 4071 PS2->getTemplateParameters(), 4072 PT2, PT1, Info, Deduced, TDF_None, 4073 /*PartialOrdering=*/true, 4074 /*RefParamComparisons=*/0); 4075 if (Better1) { 4076 InstantiatingTemplate Inst(*this, PS2->getLocation(), PS2, 4077 Deduced.data(), Deduced.size(), Info); 4078 Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, 4079 PS1->getTemplateArgs(), 4080 Deduced, Info); 4081 } 4082 4083 // Determine whether PS2 is at least as specialized as PS1 4084 Deduced.clear(); 4085 Deduced.resize(PS1->getTemplateParameters()->size()); 4086 bool Better2 = !DeduceTemplateArgumentsByTypeMatch(*this, 4087 PS1->getTemplateParameters(), 4088 PT1, PT2, Info, Deduced, TDF_None, 4089 /*PartialOrdering=*/true, 4090 /*RefParamComparisons=*/0); 4091 if (Better2) { 4092 InstantiatingTemplate Inst(*this, PS1->getLocation(), PS1, 4093 Deduced.data(), Deduced.size(), Info); 4094 Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, 4095 PS2->getTemplateArgs(), 4096 Deduced, Info); 4097 } 4098 4099 if (Better1 == Better2) 4100 return 0; 4101 4102 return Better1? PS1 : PS2; 4103} 4104 4105static void 4106MarkUsedTemplateParameters(ASTContext &Ctx, 4107 const TemplateArgument &TemplateArg, 4108 bool OnlyDeduced, 4109 unsigned Depth, 4110 llvm::SmallBitVector &Used); 4111 4112/// \brief Mark the template parameters that are used by the given 4113/// expression. 4114static void 4115MarkUsedTemplateParameters(ASTContext &Ctx, 4116 const Expr *E, 4117 bool OnlyDeduced, 4118 unsigned Depth, 4119 llvm::SmallBitVector &Used) { 4120 // We can deduce from a pack expansion. 4121 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E)) 4122 E = Expansion->getPattern(); 4123 4124 // Skip through any implicit casts we added while type-checking. 4125 while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) 4126 E = ICE->getSubExpr(); 4127 4128 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to 4129 // find other occurrences of template parameters. 4130 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E); 4131 if (!DRE) 4132 return; 4133 4134 const NonTypeTemplateParmDecl *NTTP 4135 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 4136 if (!NTTP) 4137 return; 4138 4139 if (NTTP->getDepth() == Depth) 4140 Used[NTTP->getIndex()] = true; 4141} 4142 4143/// \brief Mark the template parameters that are used by the given 4144/// nested name specifier. 4145static void 4146MarkUsedTemplateParameters(ASTContext &Ctx, 4147 NestedNameSpecifier *NNS, 4148 bool OnlyDeduced, 4149 unsigned Depth, 4150 llvm::SmallBitVector &Used) { 4151 if (!NNS) 4152 return; 4153 4154 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth, 4155 Used); 4156 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0), 4157 OnlyDeduced, Depth, Used); 4158} 4159 4160/// \brief Mark the template parameters that are used by the given 4161/// template name. 4162static void 4163MarkUsedTemplateParameters(ASTContext &Ctx, 4164 TemplateName Name, 4165 bool OnlyDeduced, 4166 unsigned Depth, 4167 llvm::SmallBitVector &Used) { 4168 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 4169 if (TemplateTemplateParmDecl *TTP 4170 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 4171 if (TTP->getDepth() == Depth) 4172 Used[TTP->getIndex()] = true; 4173 } 4174 return; 4175 } 4176 4177 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 4178 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced, 4179 Depth, Used); 4180 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 4181 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced, 4182 Depth, Used); 4183} 4184 4185/// \brief Mark the template parameters that are used by the given 4186/// type. 4187static void 4188MarkUsedTemplateParameters(ASTContext &Ctx, QualType T, 4189 bool OnlyDeduced, 4190 unsigned Depth, 4191 llvm::SmallBitVector &Used) { 4192 if (T.isNull()) 4193 return; 4194 4195 // Non-dependent types have nothing deducible 4196 if (!T->isDependentType()) 4197 return; 4198 4199 T = Ctx.getCanonicalType(T); 4200 switch (T->getTypeClass()) { 4201 case Type::Pointer: 4202 MarkUsedTemplateParameters(Ctx, 4203 cast<PointerType>(T)->getPointeeType(), 4204 OnlyDeduced, 4205 Depth, 4206 Used); 4207 break; 4208 4209 case Type::BlockPointer: 4210 MarkUsedTemplateParameters(Ctx, 4211 cast<BlockPointerType>(T)->getPointeeType(), 4212 OnlyDeduced, 4213 Depth, 4214 Used); 4215 break; 4216 4217 case Type::LValueReference: 4218 case Type::RValueReference: 4219 MarkUsedTemplateParameters(Ctx, 4220 cast<ReferenceType>(T)->getPointeeType(), 4221 OnlyDeduced, 4222 Depth, 4223 Used); 4224 break; 4225 4226 case Type::MemberPointer: { 4227 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 4228 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced, 4229 Depth, Used); 4230 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0), 4231 OnlyDeduced, Depth, Used); 4232 break; 4233 } 4234 4235 case Type::DependentSizedArray: 4236 MarkUsedTemplateParameters(Ctx, 4237 cast<DependentSizedArrayType>(T)->getSizeExpr(), 4238 OnlyDeduced, Depth, Used); 4239 // Fall through to check the element type 4240 4241 case Type::ConstantArray: 4242 case Type::IncompleteArray: 4243 MarkUsedTemplateParameters(Ctx, 4244 cast<ArrayType>(T)->getElementType(), 4245 OnlyDeduced, Depth, Used); 4246 break; 4247 4248 case Type::Vector: 4249 case Type::ExtVector: 4250 MarkUsedTemplateParameters(Ctx, 4251 cast<VectorType>(T)->getElementType(), 4252 OnlyDeduced, Depth, Used); 4253 break; 4254 4255 case Type::DependentSizedExtVector: { 4256 const DependentSizedExtVectorType *VecType 4257 = cast<DependentSizedExtVectorType>(T); 4258 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced, 4259 Depth, Used); 4260 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced, 4261 Depth, Used); 4262 break; 4263 } 4264 4265 case Type::FunctionProto: { 4266 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 4267 MarkUsedTemplateParameters(Ctx, Proto->getResultType(), OnlyDeduced, 4268 Depth, Used); 4269 for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) 4270 MarkUsedTemplateParameters(Ctx, Proto->getArgType(I), OnlyDeduced, 4271 Depth, Used); 4272 break; 4273 } 4274 4275 case Type::TemplateTypeParm: { 4276 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 4277 if (TTP->getDepth() == Depth) 4278 Used[TTP->getIndex()] = true; 4279 break; 4280 } 4281 4282 case Type::SubstTemplateTypeParmPack: { 4283 const SubstTemplateTypeParmPackType *Subst 4284 = cast<SubstTemplateTypeParmPackType>(T); 4285 MarkUsedTemplateParameters(Ctx, 4286 QualType(Subst->getReplacedParameter(), 0), 4287 OnlyDeduced, Depth, Used); 4288 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(), 4289 OnlyDeduced, Depth, Used); 4290 break; 4291 } 4292 4293 case Type::InjectedClassName: 4294 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 4295 // fall through 4296 4297 case Type::TemplateSpecialization: { 4298 const TemplateSpecializationType *Spec 4299 = cast<TemplateSpecializationType>(T); 4300 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced, 4301 Depth, Used); 4302 4303 // C++0x [temp.deduct.type]p9: 4304 // If the template argument list of P contains a pack expansion that is not 4305 // the last template argument, the entire template argument list is a 4306 // non-deduced context. 4307 if (OnlyDeduced && 4308 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) 4309 break; 4310 4311 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 4312 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 4313 Used); 4314 break; 4315 } 4316 4317 case Type::Complex: 4318 if (!OnlyDeduced) 4319 MarkUsedTemplateParameters(Ctx, 4320 cast<ComplexType>(T)->getElementType(), 4321 OnlyDeduced, Depth, Used); 4322 break; 4323 4324 case Type::Atomic: 4325 if (!OnlyDeduced) 4326 MarkUsedTemplateParameters(Ctx, 4327 cast<AtomicType>(T)->getValueType(), 4328 OnlyDeduced, Depth, Used); 4329 break; 4330 4331 case Type::DependentName: 4332 if (!OnlyDeduced) 4333 MarkUsedTemplateParameters(Ctx, 4334 cast<DependentNameType>(T)->getQualifier(), 4335 OnlyDeduced, Depth, Used); 4336 break; 4337 4338 case Type::DependentTemplateSpecialization: { 4339 const DependentTemplateSpecializationType *Spec 4340 = cast<DependentTemplateSpecializationType>(T); 4341 if (!OnlyDeduced) 4342 MarkUsedTemplateParameters(Ctx, Spec->getQualifier(), 4343 OnlyDeduced, Depth, Used); 4344 4345 // C++0x [temp.deduct.type]p9: 4346 // If the template argument list of P contains a pack expansion that is not 4347 // the last template argument, the entire template argument list is a 4348 // non-deduced context. 4349 if (OnlyDeduced && 4350 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs())) 4351 break; 4352 4353 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 4354 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth, 4355 Used); 4356 break; 4357 } 4358 4359 case Type::TypeOf: 4360 if (!OnlyDeduced) 4361 MarkUsedTemplateParameters(Ctx, 4362 cast<TypeOfType>(T)->getUnderlyingType(), 4363 OnlyDeduced, Depth, Used); 4364 break; 4365 4366 case Type::TypeOfExpr: 4367 if (!OnlyDeduced) 4368 MarkUsedTemplateParameters(Ctx, 4369 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 4370 OnlyDeduced, Depth, Used); 4371 break; 4372 4373 case Type::Decltype: 4374 if (!OnlyDeduced) 4375 MarkUsedTemplateParameters(Ctx, 4376 cast<DecltypeType>(T)->getUnderlyingExpr(), 4377 OnlyDeduced, Depth, Used); 4378 break; 4379 4380 case Type::UnaryTransform: 4381 if (!OnlyDeduced) 4382 MarkUsedTemplateParameters(Ctx, 4383 cast<UnaryTransformType>(T)->getUnderlyingType(), 4384 OnlyDeduced, Depth, Used); 4385 break; 4386 4387 case Type::PackExpansion: 4388 MarkUsedTemplateParameters(Ctx, 4389 cast<PackExpansionType>(T)->getPattern(), 4390 OnlyDeduced, Depth, Used); 4391 break; 4392 4393 case Type::Auto: 4394 MarkUsedTemplateParameters(Ctx, 4395 cast<AutoType>(T)->getDeducedType(), 4396 OnlyDeduced, Depth, Used); 4397 4398 // None of these types have any template parameters in them. 4399 case Type::Builtin: 4400 case Type::VariableArray: 4401 case Type::FunctionNoProto: 4402 case Type::Record: 4403 case Type::Enum: 4404 case Type::ObjCInterface: 4405 case Type::ObjCObject: 4406 case Type::ObjCObjectPointer: 4407 case Type::UnresolvedUsing: 4408#define TYPE(Class, Base) 4409#define ABSTRACT_TYPE(Class, Base) 4410#define DEPENDENT_TYPE(Class, Base) 4411#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 4412#include "clang/AST/TypeNodes.def" 4413 break; 4414 } 4415} 4416 4417/// \brief Mark the template parameters that are used by this 4418/// template argument. 4419static void 4420MarkUsedTemplateParameters(ASTContext &Ctx, 4421 const TemplateArgument &TemplateArg, 4422 bool OnlyDeduced, 4423 unsigned Depth, 4424 llvm::SmallBitVector &Used) { 4425 switch (TemplateArg.getKind()) { 4426 case TemplateArgument::Null: 4427 case TemplateArgument::Integral: 4428 case TemplateArgument::Declaration: 4429 break; 4430 4431 case TemplateArgument::Type: 4432 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced, 4433 Depth, Used); 4434 break; 4435 4436 case TemplateArgument::Template: 4437 case TemplateArgument::TemplateExpansion: 4438 MarkUsedTemplateParameters(Ctx, 4439 TemplateArg.getAsTemplateOrTemplatePattern(), 4440 OnlyDeduced, Depth, Used); 4441 break; 4442 4443 case TemplateArgument::Expression: 4444 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced, 4445 Depth, Used); 4446 break; 4447 4448 case TemplateArgument::Pack: 4449 for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), 4450 PEnd = TemplateArg.pack_end(); 4451 P != PEnd; ++P) 4452 MarkUsedTemplateParameters(Ctx, *P, OnlyDeduced, Depth, Used); 4453 break; 4454 } 4455} 4456 4457/// \brief Mark the template parameters can be deduced by the given 4458/// template argument list. 4459/// 4460/// \param TemplateArgs the template argument list from which template 4461/// parameters will be deduced. 4462/// 4463/// \param Deduced a bit vector whose elements will be set to \c true 4464/// to indicate when the corresponding template parameter will be 4465/// deduced. 4466void 4467Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 4468 bool OnlyDeduced, unsigned Depth, 4469 llvm::SmallBitVector &Used) { 4470 // C++0x [temp.deduct.type]p9: 4471 // If the template argument list of P contains a pack expansion that is not 4472 // the last template argument, the entire template argument list is a 4473 // non-deduced context. 4474 if (OnlyDeduced && 4475 hasPackExpansionBeforeEnd(TemplateArgs.data(), TemplateArgs.size())) 4476 return; 4477 4478 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 4479 ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced, 4480 Depth, Used); 4481} 4482 4483/// \brief Marks all of the template parameters that will be deduced by a 4484/// call to the given function template. 4485void 4486Sema::MarkDeducedTemplateParameters(ASTContext &Ctx, 4487 FunctionTemplateDecl *FunctionTemplate, 4488 llvm::SmallBitVector &Deduced) { 4489 TemplateParameterList *TemplateParams 4490 = FunctionTemplate->getTemplateParameters(); 4491 Deduced.clear(); 4492 Deduced.resize(TemplateParams->size()); 4493 4494 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 4495 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 4496 ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(), 4497 true, TemplateParams->getDepth(), Deduced); 4498} 4499 4500bool hasDeducibleTemplateParameters(Sema &S, 4501 FunctionTemplateDecl *FunctionTemplate, 4502 QualType T) { 4503 if (!T->isDependentType()) 4504 return false; 4505 4506 TemplateParameterList *TemplateParams 4507 = FunctionTemplate->getTemplateParameters(); 4508 llvm::SmallBitVector Deduced(TemplateParams->size()); 4509 ::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(), 4510 Deduced); 4511 4512 return Deduced.any(); 4513} 4514