SemaTemplateDeduction.cpp revision 33500955d731c73717af52088b7fc0e7a85681e7
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 "Sema.h" 14#include "clang/AST/ASTContext.h" 15#include "clang/AST/DeclTemplate.h" 16#include "clang/AST/StmtVisitor.h" 17#include "clang/AST/Expr.h" 18#include "clang/AST/ExprCXX.h" 19#include "clang/Parse/DeclSpec.h" 20#include <algorithm> 21 22namespace clang { 23 /// \brief Various flags that control template argument deduction. 24 /// 25 /// These flags can be bitwise-OR'd together. 26 enum TemplateDeductionFlags { 27 /// \brief No template argument deduction flags, which indicates the 28 /// strictest results for template argument deduction (as used for, e.g., 29 /// matching class template partial specializations). 30 TDF_None = 0, 31 /// \brief Within template argument deduction from a function call, we are 32 /// matching with a parameter type for which the original parameter was 33 /// a reference. 34 TDF_ParamWithReferenceType = 0x1, 35 /// \brief Within template argument deduction from a function call, we 36 /// are matching in a case where we ignore cv-qualifiers. 37 TDF_IgnoreQualifiers = 0x02, 38 /// \brief Within template argument deduction from a function call, 39 /// we are matching in a case where we can perform template argument 40 /// deduction from a template-id of a derived class of the argument type. 41 TDF_DerivedClass = 0x04, 42 /// \brief Allow non-dependent types to differ, e.g., when performing 43 /// template argument deduction from a function call where conversions 44 /// may apply. 45 TDF_SkipNonDependent = 0x08 46 }; 47} 48 49using namespace clang; 50 51/// \brief Compare two APSInts, extending and switching the sign as 52/// necessary to compare their values regardless of underlying type. 53static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) { 54 if (Y.getBitWidth() > X.getBitWidth()) 55 X.extend(Y.getBitWidth()); 56 else if (Y.getBitWidth() < X.getBitWidth()) 57 Y.extend(X.getBitWidth()); 58 59 // If there is a signedness mismatch, correct it. 60 if (X.isSigned() != Y.isSigned()) { 61 // If the signed value is negative, then the values cannot be the same. 62 if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative())) 63 return false; 64 65 Y.setIsSigned(true); 66 X.setIsSigned(true); 67 } 68 69 return X == Y; 70} 71 72static Sema::TemplateDeductionResult 73DeduceTemplateArguments(Sema &S, 74 TemplateParameterList *TemplateParams, 75 const TemplateArgument &Param, 76 const TemplateArgument &Arg, 77 Sema::TemplateDeductionInfo &Info, 78 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced); 79 80/// \brief If the given expression is of a form that permits the deduction 81/// of a non-type template parameter, return the declaration of that 82/// non-type template parameter. 83static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) { 84 if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E)) 85 E = IC->getSubExpr(); 86 87 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 88 return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 89 90 return 0; 91} 92 93/// \brief Deduce the value of the given non-type template parameter 94/// from the given constant. 95static Sema::TemplateDeductionResult 96DeduceNonTypeTemplateArgument(Sema &S, 97 NonTypeTemplateParmDecl *NTTP, 98 llvm::APSInt Value, QualType ValueType, 99 bool DeducedFromArrayBound, 100 Sema::TemplateDeductionInfo &Info, 101 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 102 assert(NTTP->getDepth() == 0 && 103 "Cannot deduce non-type template argument with depth > 0"); 104 105 if (Deduced[NTTP->getIndex()].isNull()) { 106 Deduced[NTTP->getIndex()] = DeducedTemplateArgument(Value, ValueType, 107 DeducedFromArrayBound); 108 return Sema::TDK_Success; 109 } 110 111 if (Deduced[NTTP->getIndex()].getKind() != TemplateArgument::Integral) { 112 Info.Param = NTTP; 113 Info.FirstArg = Deduced[NTTP->getIndex()]; 114 Info.SecondArg = TemplateArgument(Value, ValueType); 115 return Sema::TDK_Inconsistent; 116 } 117 118 // Extent the smaller of the two values. 119 llvm::APSInt PrevValue = *Deduced[NTTP->getIndex()].getAsIntegral(); 120 if (!hasSameExtendedValue(PrevValue, Value)) { 121 Info.Param = NTTP; 122 Info.FirstArg = Deduced[NTTP->getIndex()]; 123 Info.SecondArg = TemplateArgument(Value, ValueType); 124 return Sema::TDK_Inconsistent; 125 } 126 127 if (!DeducedFromArrayBound) 128 Deduced[NTTP->getIndex()].setDeducedFromArrayBound(false); 129 130 return Sema::TDK_Success; 131} 132 133/// \brief Deduce the value of the given non-type template parameter 134/// from the given type- or value-dependent expression. 135/// 136/// \returns true if deduction succeeded, false otherwise. 137static Sema::TemplateDeductionResult 138DeduceNonTypeTemplateArgument(Sema &S, 139 NonTypeTemplateParmDecl *NTTP, 140 Expr *Value, 141 Sema::TemplateDeductionInfo &Info, 142 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 143 assert(NTTP->getDepth() == 0 && 144 "Cannot deduce non-type template argument with depth > 0"); 145 assert((Value->isTypeDependent() || Value->isValueDependent()) && 146 "Expression template argument must be type- or value-dependent."); 147 148 if (Deduced[NTTP->getIndex()].isNull()) { 149 Deduced[NTTP->getIndex()] = TemplateArgument(Value->Retain()); 150 return Sema::TDK_Success; 151 } 152 153 if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Integral) { 154 // Okay, we deduced a constant in one case and a dependent expression 155 // in another case. FIXME: Later, we will check that instantiating the 156 // dependent expression gives us the constant value. 157 return Sema::TDK_Success; 158 } 159 160 if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Expression) { 161 // Compare the expressions for equality 162 llvm::FoldingSetNodeID ID1, ID2; 163 Deduced[NTTP->getIndex()].getAsExpr()->Profile(ID1, S.Context, true); 164 Value->Profile(ID2, S.Context, true); 165 if (ID1 == ID2) 166 return Sema::TDK_Success; 167 168 // FIXME: Fill in argument mismatch information 169 return Sema::TDK_NonDeducedMismatch; 170 } 171 172 return Sema::TDK_Success; 173} 174 175/// \brief Deduce the value of the given non-type template parameter 176/// from the given declaration. 177/// 178/// \returns true if deduction succeeded, false otherwise. 179static Sema::TemplateDeductionResult 180DeduceNonTypeTemplateArgument(Sema &S, 181 NonTypeTemplateParmDecl *NTTP, 182 Decl *D, 183 Sema::TemplateDeductionInfo &Info, 184 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 185 assert(NTTP->getDepth() == 0 && 186 "Cannot deduce non-type template argument with depth > 0"); 187 188 if (Deduced[NTTP->getIndex()].isNull()) { 189 Deduced[NTTP->getIndex()] = TemplateArgument(D->getCanonicalDecl()); 190 return Sema::TDK_Success; 191 } 192 193 if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Expression) { 194 // Okay, we deduced a declaration in one case and a dependent expression 195 // in another case. 196 return Sema::TDK_Success; 197 } 198 199 if (Deduced[NTTP->getIndex()].getKind() == TemplateArgument::Declaration) { 200 // Compare the declarations for equality 201 if (Deduced[NTTP->getIndex()].getAsDecl()->getCanonicalDecl() == 202 D->getCanonicalDecl()) 203 return Sema::TDK_Success; 204 205 // FIXME: Fill in argument mismatch information 206 return Sema::TDK_NonDeducedMismatch; 207 } 208 209 return Sema::TDK_Success; 210} 211 212static Sema::TemplateDeductionResult 213DeduceTemplateArguments(Sema &S, 214 TemplateParameterList *TemplateParams, 215 TemplateName Param, 216 TemplateName Arg, 217 Sema::TemplateDeductionInfo &Info, 218 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 219 TemplateDecl *ParamDecl = Param.getAsTemplateDecl(); 220 if (!ParamDecl) { 221 // The parameter type is dependent and is not a template template parameter, 222 // so there is nothing that we can deduce. 223 return Sema::TDK_Success; 224 } 225 226 if (TemplateTemplateParmDecl *TempParam 227 = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) { 228 // Bind the template template parameter to the given template name. 229 TemplateArgument &ExistingArg = Deduced[TempParam->getIndex()]; 230 if (ExistingArg.isNull()) { 231 // This is the first deduction for this template template parameter. 232 ExistingArg = TemplateArgument(S.Context.getCanonicalTemplateName(Arg)); 233 return Sema::TDK_Success; 234 } 235 236 // Verify that the previous binding matches this deduction. 237 assert(ExistingArg.getKind() == TemplateArgument::Template); 238 if (S.Context.hasSameTemplateName(ExistingArg.getAsTemplate(), Arg)) 239 return Sema::TDK_Success; 240 241 // Inconsistent deduction. 242 Info.Param = TempParam; 243 Info.FirstArg = ExistingArg; 244 Info.SecondArg = TemplateArgument(Arg); 245 return Sema::TDK_Inconsistent; 246 } 247 248 // Verify that the two template names are equivalent. 249 if (S.Context.hasSameTemplateName(Param, Arg)) 250 return Sema::TDK_Success; 251 252 // Mismatch of non-dependent template parameter to argument. 253 Info.FirstArg = TemplateArgument(Param); 254 Info.SecondArg = TemplateArgument(Arg); 255 return Sema::TDK_NonDeducedMismatch; 256} 257 258/// \brief Deduce the template arguments by comparing the template parameter 259/// type (which is a template-id) with the template argument type. 260/// 261/// \param S the Sema 262/// 263/// \param TemplateParams the template parameters that we are deducing 264/// 265/// \param Param the parameter type 266/// 267/// \param Arg the argument type 268/// 269/// \param Info information about the template argument deduction itself 270/// 271/// \param Deduced the deduced template arguments 272/// 273/// \returns the result of template argument deduction so far. Note that a 274/// "success" result means that template argument deduction has not yet failed, 275/// but it may still fail, later, for other reasons. 276static Sema::TemplateDeductionResult 277DeduceTemplateArguments(Sema &S, 278 TemplateParameterList *TemplateParams, 279 const TemplateSpecializationType *Param, 280 QualType Arg, 281 Sema::TemplateDeductionInfo &Info, 282 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 283 assert(Arg.isCanonical() && "Argument type must be canonical"); 284 285 // Check whether the template argument is a dependent template-id. 286 if (const TemplateSpecializationType *SpecArg 287 = dyn_cast<TemplateSpecializationType>(Arg)) { 288 // Perform template argument deduction for the template name. 289 if (Sema::TemplateDeductionResult Result 290 = DeduceTemplateArguments(S, TemplateParams, 291 Param->getTemplateName(), 292 SpecArg->getTemplateName(), 293 Info, Deduced)) 294 return Result; 295 296 297 // Perform template argument deduction on each template 298 // argument. 299 unsigned NumArgs = std::min(SpecArg->getNumArgs(), Param->getNumArgs()); 300 for (unsigned I = 0; I != NumArgs; ++I) 301 if (Sema::TemplateDeductionResult Result 302 = DeduceTemplateArguments(S, TemplateParams, 303 Param->getArg(I), 304 SpecArg->getArg(I), 305 Info, Deduced)) 306 return Result; 307 308 return Sema::TDK_Success; 309 } 310 311 // If the argument type is a class template specialization, we 312 // perform template argument deduction using its template 313 // arguments. 314 const RecordType *RecordArg = dyn_cast<RecordType>(Arg); 315 if (!RecordArg) 316 return Sema::TDK_NonDeducedMismatch; 317 318 ClassTemplateSpecializationDecl *SpecArg 319 = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl()); 320 if (!SpecArg) 321 return Sema::TDK_NonDeducedMismatch; 322 323 // Perform template argument deduction for the template name. 324 if (Sema::TemplateDeductionResult Result 325 = DeduceTemplateArguments(S, 326 TemplateParams, 327 Param->getTemplateName(), 328 TemplateName(SpecArg->getSpecializedTemplate()), 329 Info, Deduced)) 330 return Result; 331 332 unsigned NumArgs = Param->getNumArgs(); 333 const TemplateArgumentList &ArgArgs = SpecArg->getTemplateArgs(); 334 if (NumArgs != ArgArgs.size()) 335 return Sema::TDK_NonDeducedMismatch; 336 337 for (unsigned I = 0; I != NumArgs; ++I) 338 if (Sema::TemplateDeductionResult Result 339 = DeduceTemplateArguments(S, TemplateParams, 340 Param->getArg(I), 341 ArgArgs.get(I), 342 Info, Deduced)) 343 return Result; 344 345 return Sema::TDK_Success; 346} 347 348/// \brief Deduce the template arguments by comparing the parameter type and 349/// the argument type (C++ [temp.deduct.type]). 350/// 351/// \param S the semantic analysis object within which we are deducing 352/// 353/// \param TemplateParams the template parameters that we are deducing 354/// 355/// \param ParamIn the parameter type 356/// 357/// \param ArgIn the argument type 358/// 359/// \param Info information about the template argument deduction itself 360/// 361/// \param Deduced the deduced template arguments 362/// 363/// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe 364/// how template argument deduction is performed. 365/// 366/// \returns the result of template argument deduction so far. Note that a 367/// "success" result means that template argument deduction has not yet failed, 368/// but it may still fail, later, for other reasons. 369static Sema::TemplateDeductionResult 370DeduceTemplateArguments(Sema &S, 371 TemplateParameterList *TemplateParams, 372 QualType ParamIn, QualType ArgIn, 373 Sema::TemplateDeductionInfo &Info, 374 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 375 unsigned TDF) { 376 // We only want to look at the canonical types, since typedefs and 377 // sugar are not part of template argument deduction. 378 QualType Param = S.Context.getCanonicalType(ParamIn); 379 QualType Arg = S.Context.getCanonicalType(ArgIn); 380 381 // C++0x [temp.deduct.call]p4 bullet 1: 382 // - If the original P is a reference type, the deduced A (i.e., the type 383 // referred to by the reference) can be more cv-qualified than the 384 // transformed A. 385 if (TDF & TDF_ParamWithReferenceType) { 386 Qualifiers Quals; 387 QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals); 388 Quals.setCVRQualifiers(Quals.getCVRQualifiers() & 389 Arg.getCVRQualifiersThroughArrayTypes()); 390 Param = S.Context.getQualifiedType(UnqualParam, Quals); 391 } 392 393 // If the parameter type is not dependent, there is nothing to deduce. 394 if (!Param->isDependentType()) { 395 if (!(TDF & TDF_SkipNonDependent) && Param != Arg) { 396 397 return Sema::TDK_NonDeducedMismatch; 398 } 399 400 return Sema::TDK_Success; 401 } 402 403 // C++ [temp.deduct.type]p9: 404 // A template type argument T, a template template argument TT or a 405 // template non-type argument i can be deduced if P and A have one of 406 // the following forms: 407 // 408 // T 409 // cv-list T 410 if (const TemplateTypeParmType *TemplateTypeParm 411 = Param->getAs<TemplateTypeParmType>()) { 412 unsigned Index = TemplateTypeParm->getIndex(); 413 bool RecanonicalizeArg = false; 414 415 // If the argument type is an array type, move the qualifiers up to the 416 // top level, so they can be matched with the qualifiers on the parameter. 417 // FIXME: address spaces, ObjC GC qualifiers 418 if (isa<ArrayType>(Arg)) { 419 Qualifiers Quals; 420 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals); 421 if (Quals) { 422 Arg = S.Context.getQualifiedType(Arg, Quals); 423 RecanonicalizeArg = true; 424 } 425 } 426 427 // The argument type can not be less qualified than the parameter 428 // type. 429 if (Param.isMoreQualifiedThan(Arg) && !(TDF & TDF_IgnoreQualifiers)) { 430 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 431 Info.FirstArg = Deduced[Index]; 432 Info.SecondArg = TemplateArgument(Arg); 433 return Sema::TDK_InconsistentQuals; 434 } 435 436 assert(TemplateTypeParm->getDepth() == 0 && "Can't deduce with depth > 0"); 437 assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function"); 438 QualType DeducedType = Arg; 439 DeducedType.removeCVRQualifiers(Param.getCVRQualifiers()); 440 if (RecanonicalizeArg) 441 DeducedType = S.Context.getCanonicalType(DeducedType); 442 443 if (Deduced[Index].isNull()) 444 Deduced[Index] = TemplateArgument(DeducedType); 445 else { 446 // C++ [temp.deduct.type]p2: 447 // [...] If type deduction cannot be done for any P/A pair, or if for 448 // any pair the deduction leads to more than one possible set of 449 // deduced values, or if different pairs yield different deduced 450 // values, or if any template argument remains neither deduced nor 451 // explicitly specified, template argument deduction fails. 452 if (Deduced[Index].getAsType() != DeducedType) { 453 Info.Param 454 = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index)); 455 Info.FirstArg = Deduced[Index]; 456 Info.SecondArg = TemplateArgument(Arg); 457 return Sema::TDK_Inconsistent; 458 } 459 } 460 return Sema::TDK_Success; 461 } 462 463 // Set up the template argument deduction information for a failure. 464 Info.FirstArg = TemplateArgument(ParamIn); 465 Info.SecondArg = TemplateArgument(ArgIn); 466 467 // Check the cv-qualifiers on the parameter and argument types. 468 if (!(TDF & TDF_IgnoreQualifiers)) { 469 if (TDF & TDF_ParamWithReferenceType) { 470 if (Param.isMoreQualifiedThan(Arg)) 471 return Sema::TDK_NonDeducedMismatch; 472 } else { 473 if (Param.getCVRQualifiers() != Arg.getCVRQualifiers()) 474 return Sema::TDK_NonDeducedMismatch; 475 } 476 } 477 478 switch (Param->getTypeClass()) { 479 // No deduction possible for these types 480 case Type::Builtin: 481 return Sema::TDK_NonDeducedMismatch; 482 483 // T * 484 case Type::Pointer: { 485 QualType PointeeType; 486 if (const PointerType *PointerArg = Arg->getAs<PointerType>()) { 487 PointeeType = PointerArg->getPointeeType(); 488 } else if (const ObjCObjectPointerType *PointerArg 489 = Arg->getAs<ObjCObjectPointerType>()) { 490 PointeeType = PointerArg->getPointeeType(); 491 } else { 492 return Sema::TDK_NonDeducedMismatch; 493 } 494 495 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass); 496 return DeduceTemplateArguments(S, TemplateParams, 497 cast<PointerType>(Param)->getPointeeType(), 498 PointeeType, 499 Info, Deduced, SubTDF); 500 } 501 502 // T & 503 case Type::LValueReference: { 504 const LValueReferenceType *ReferenceArg = Arg->getAs<LValueReferenceType>(); 505 if (!ReferenceArg) 506 return Sema::TDK_NonDeducedMismatch; 507 508 return DeduceTemplateArguments(S, TemplateParams, 509 cast<LValueReferenceType>(Param)->getPointeeType(), 510 ReferenceArg->getPointeeType(), 511 Info, Deduced, 0); 512 } 513 514 // T && [C++0x] 515 case Type::RValueReference: { 516 const RValueReferenceType *ReferenceArg = Arg->getAs<RValueReferenceType>(); 517 if (!ReferenceArg) 518 return Sema::TDK_NonDeducedMismatch; 519 520 return DeduceTemplateArguments(S, TemplateParams, 521 cast<RValueReferenceType>(Param)->getPointeeType(), 522 ReferenceArg->getPointeeType(), 523 Info, Deduced, 0); 524 } 525 526 // T [] (implied, but not stated explicitly) 527 case Type::IncompleteArray: { 528 const IncompleteArrayType *IncompleteArrayArg = 529 S.Context.getAsIncompleteArrayType(Arg); 530 if (!IncompleteArrayArg) 531 return Sema::TDK_NonDeducedMismatch; 532 533 return DeduceTemplateArguments(S, TemplateParams, 534 S.Context.getAsIncompleteArrayType(Param)->getElementType(), 535 IncompleteArrayArg->getElementType(), 536 Info, Deduced, 0); 537 } 538 539 // T [integer-constant] 540 case Type::ConstantArray: { 541 const ConstantArrayType *ConstantArrayArg = 542 S.Context.getAsConstantArrayType(Arg); 543 if (!ConstantArrayArg) 544 return Sema::TDK_NonDeducedMismatch; 545 546 const ConstantArrayType *ConstantArrayParm = 547 S.Context.getAsConstantArrayType(Param); 548 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize()) 549 return Sema::TDK_NonDeducedMismatch; 550 551 return DeduceTemplateArguments(S, TemplateParams, 552 ConstantArrayParm->getElementType(), 553 ConstantArrayArg->getElementType(), 554 Info, Deduced, 0); 555 } 556 557 // type [i] 558 case Type::DependentSizedArray: { 559 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg); 560 if (!ArrayArg) 561 return Sema::TDK_NonDeducedMismatch; 562 563 // Check the element type of the arrays 564 const DependentSizedArrayType *DependentArrayParm 565 = S.Context.getAsDependentSizedArrayType(Param); 566 if (Sema::TemplateDeductionResult Result 567 = DeduceTemplateArguments(S, TemplateParams, 568 DependentArrayParm->getElementType(), 569 ArrayArg->getElementType(), 570 Info, Deduced, 0)) 571 return Result; 572 573 // Determine the array bound is something we can deduce. 574 NonTypeTemplateParmDecl *NTTP 575 = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr()); 576 if (!NTTP) 577 return Sema::TDK_Success; 578 579 // We can perform template argument deduction for the given non-type 580 // template parameter. 581 assert(NTTP->getDepth() == 0 && 582 "Cannot deduce non-type template argument at depth > 0"); 583 if (const ConstantArrayType *ConstantArrayArg 584 = dyn_cast<ConstantArrayType>(ArrayArg)) { 585 llvm::APSInt Size(ConstantArrayArg->getSize()); 586 return DeduceNonTypeTemplateArgument(S, NTTP, Size, 587 S.Context.getSizeType(), 588 /*ArrayBound=*/true, 589 Info, Deduced); 590 } 591 if (const DependentSizedArrayType *DependentArrayArg 592 = dyn_cast<DependentSizedArrayType>(ArrayArg)) 593 return DeduceNonTypeTemplateArgument(S, NTTP, 594 DependentArrayArg->getSizeExpr(), 595 Info, Deduced); 596 597 // Incomplete type does not match a dependently-sized array type 598 return Sema::TDK_NonDeducedMismatch; 599 } 600 601 // type(*)(T) 602 // T(*)() 603 // T(*)(T) 604 case Type::FunctionProto: { 605 const FunctionProtoType *FunctionProtoArg = 606 dyn_cast<FunctionProtoType>(Arg); 607 if (!FunctionProtoArg) 608 return Sema::TDK_NonDeducedMismatch; 609 610 const FunctionProtoType *FunctionProtoParam = 611 cast<FunctionProtoType>(Param); 612 613 if (FunctionProtoParam->getTypeQuals() != 614 FunctionProtoArg->getTypeQuals()) 615 return Sema::TDK_NonDeducedMismatch; 616 617 if (FunctionProtoParam->getNumArgs() != FunctionProtoArg->getNumArgs()) 618 return Sema::TDK_NonDeducedMismatch; 619 620 if (FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic()) 621 return Sema::TDK_NonDeducedMismatch; 622 623 // Check return types. 624 if (Sema::TemplateDeductionResult Result 625 = DeduceTemplateArguments(S, TemplateParams, 626 FunctionProtoParam->getResultType(), 627 FunctionProtoArg->getResultType(), 628 Info, Deduced, 0)) 629 return Result; 630 631 for (unsigned I = 0, N = FunctionProtoParam->getNumArgs(); I != N; ++I) { 632 // Check argument types. 633 if (Sema::TemplateDeductionResult Result 634 = DeduceTemplateArguments(S, TemplateParams, 635 FunctionProtoParam->getArgType(I), 636 FunctionProtoArg->getArgType(I), 637 Info, Deduced, 0)) 638 return Result; 639 } 640 641 return Sema::TDK_Success; 642 } 643 644 case Type::InjectedClassName: { 645 // Treat a template's injected-class-name as if the template 646 // specialization type had been used. 647 Param = cast<InjectedClassNameType>(Param) 648 ->getInjectedSpecializationType(); 649 assert(isa<TemplateSpecializationType>(Param) && 650 "injected class name is not a template specialization type"); 651 // fall through 652 } 653 654 // template-name<T> (where template-name refers to a class template) 655 // template-name<i> 656 // TT<T> 657 // TT<i> 658 // TT<> 659 case Type::TemplateSpecialization: { 660 const TemplateSpecializationType *SpecParam 661 = cast<TemplateSpecializationType>(Param); 662 663 // Try to deduce template arguments from the template-id. 664 Sema::TemplateDeductionResult Result 665 = DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, 666 Info, Deduced); 667 668 if (Result && (TDF & TDF_DerivedClass)) { 669 // C++ [temp.deduct.call]p3b3: 670 // If P is a class, and P has the form template-id, then A can be a 671 // derived class of the deduced A. Likewise, if P is a pointer to a 672 // class of the form template-id, A can be a pointer to a derived 673 // class pointed to by the deduced A. 674 // 675 // More importantly: 676 // These alternatives are considered only if type deduction would 677 // otherwise fail. 678 if (const RecordType *RecordT = Arg->getAs<RecordType>()) { 679 // We cannot inspect base classes as part of deduction when the type 680 // is incomplete, so either instantiate any templates necessary to 681 // complete the type, or skip over it if it cannot be completed. 682 if (S.RequireCompleteType(Info.getLocation(), Arg, 0)) 683 return Result; 684 685 // Use data recursion to crawl through the list of base classes. 686 // Visited contains the set of nodes we have already visited, while 687 // ToVisit is our stack of records that we still need to visit. 688 llvm::SmallPtrSet<const RecordType *, 8> Visited; 689 llvm::SmallVector<const RecordType *, 8> ToVisit; 690 ToVisit.push_back(RecordT); 691 bool Successful = false; 692 while (!ToVisit.empty()) { 693 // Retrieve the next class in the inheritance hierarchy. 694 const RecordType *NextT = ToVisit.back(); 695 ToVisit.pop_back(); 696 697 // If we have already seen this type, skip it. 698 if (!Visited.insert(NextT)) 699 continue; 700 701 // If this is a base class, try to perform template argument 702 // deduction from it. 703 if (NextT != RecordT) { 704 Sema::TemplateDeductionResult BaseResult 705 = DeduceTemplateArguments(S, TemplateParams, SpecParam, 706 QualType(NextT, 0), Info, Deduced); 707 708 // If template argument deduction for this base was successful, 709 // note that we had some success. 710 if (BaseResult == Sema::TDK_Success) 711 Successful = true; 712 } 713 714 // Visit base classes 715 CXXRecordDecl *Next = cast<CXXRecordDecl>(NextT->getDecl()); 716 for (CXXRecordDecl::base_class_iterator Base = Next->bases_begin(), 717 BaseEnd = Next->bases_end(); 718 Base != BaseEnd; ++Base) { 719 assert(Base->getType()->isRecordType() && 720 "Base class that isn't a record?"); 721 ToVisit.push_back(Base->getType()->getAs<RecordType>()); 722 } 723 } 724 725 if (Successful) 726 return Sema::TDK_Success; 727 } 728 729 } 730 731 return Result; 732 } 733 734 // T type::* 735 // T T::* 736 // T (type::*)() 737 // type (T::*)() 738 // type (type::*)(T) 739 // type (T::*)(T) 740 // T (type::*)(T) 741 // T (T::*)() 742 // T (T::*)(T) 743 case Type::MemberPointer: { 744 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param); 745 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg); 746 if (!MemPtrArg) 747 return Sema::TDK_NonDeducedMismatch; 748 749 if (Sema::TemplateDeductionResult Result 750 = DeduceTemplateArguments(S, TemplateParams, 751 MemPtrParam->getPointeeType(), 752 MemPtrArg->getPointeeType(), 753 Info, Deduced, 754 TDF & TDF_IgnoreQualifiers)) 755 return Result; 756 757 return DeduceTemplateArguments(S, TemplateParams, 758 QualType(MemPtrParam->getClass(), 0), 759 QualType(MemPtrArg->getClass(), 0), 760 Info, Deduced, 0); 761 } 762 763 // (clang extension) 764 // 765 // type(^)(T) 766 // T(^)() 767 // T(^)(T) 768 case Type::BlockPointer: { 769 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param); 770 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg); 771 772 if (!BlockPtrArg) 773 return Sema::TDK_NonDeducedMismatch; 774 775 return DeduceTemplateArguments(S, TemplateParams, 776 BlockPtrParam->getPointeeType(), 777 BlockPtrArg->getPointeeType(), Info, 778 Deduced, 0); 779 } 780 781 case Type::TypeOfExpr: 782 case Type::TypeOf: 783 case Type::DependentName: 784 // No template argument deduction for these types 785 return Sema::TDK_Success; 786 787 default: 788 break; 789 } 790 791 // FIXME: Many more cases to go (to go). 792 return Sema::TDK_Success; 793} 794 795static Sema::TemplateDeductionResult 796DeduceTemplateArguments(Sema &S, 797 TemplateParameterList *TemplateParams, 798 const TemplateArgument &Param, 799 const TemplateArgument &Arg, 800 Sema::TemplateDeductionInfo &Info, 801 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 802 switch (Param.getKind()) { 803 case TemplateArgument::Null: 804 assert(false && "Null template argument in parameter list"); 805 break; 806 807 case TemplateArgument::Type: 808 if (Arg.getKind() == TemplateArgument::Type) 809 return DeduceTemplateArguments(S, TemplateParams, Param.getAsType(), 810 Arg.getAsType(), Info, Deduced, 0); 811 Info.FirstArg = Param; 812 Info.SecondArg = Arg; 813 return Sema::TDK_NonDeducedMismatch; 814 815 case TemplateArgument::Template: 816 if (Arg.getKind() == TemplateArgument::Template) 817 return DeduceTemplateArguments(S, TemplateParams, 818 Param.getAsTemplate(), 819 Arg.getAsTemplate(), Info, Deduced); 820 Info.FirstArg = Param; 821 Info.SecondArg = Arg; 822 return Sema::TDK_NonDeducedMismatch; 823 824 case TemplateArgument::Declaration: 825 if (Arg.getKind() == TemplateArgument::Declaration && 826 Param.getAsDecl()->getCanonicalDecl() == 827 Arg.getAsDecl()->getCanonicalDecl()) 828 return Sema::TDK_Success; 829 830 Info.FirstArg = Param; 831 Info.SecondArg = Arg; 832 return Sema::TDK_NonDeducedMismatch; 833 834 case TemplateArgument::Integral: 835 if (Arg.getKind() == TemplateArgument::Integral) { 836 if (hasSameExtendedValue(*Param.getAsIntegral(), *Arg.getAsIntegral())) 837 return Sema::TDK_Success; 838 839 Info.FirstArg = Param; 840 Info.SecondArg = Arg; 841 return Sema::TDK_NonDeducedMismatch; 842 } 843 844 if (Arg.getKind() == TemplateArgument::Expression) { 845 Info.FirstArg = Param; 846 Info.SecondArg = Arg; 847 return Sema::TDK_NonDeducedMismatch; 848 } 849 850 assert(false && "Type/value mismatch"); 851 Info.FirstArg = Param; 852 Info.SecondArg = Arg; 853 return Sema::TDK_NonDeducedMismatch; 854 855 case TemplateArgument::Expression: { 856 if (NonTypeTemplateParmDecl *NTTP 857 = getDeducedParameterFromExpr(Param.getAsExpr())) { 858 if (Arg.getKind() == TemplateArgument::Integral) 859 return DeduceNonTypeTemplateArgument(S, NTTP, 860 *Arg.getAsIntegral(), 861 Arg.getIntegralType(), 862 /*ArrayBound=*/false, 863 Info, Deduced); 864 if (Arg.getKind() == TemplateArgument::Expression) 865 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsExpr(), 866 Info, Deduced); 867 if (Arg.getKind() == TemplateArgument::Declaration) 868 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsDecl(), 869 Info, Deduced); 870 871 assert(false && "Type/value mismatch"); 872 Info.FirstArg = Param; 873 Info.SecondArg = Arg; 874 return Sema::TDK_NonDeducedMismatch; 875 } 876 877 // Can't deduce anything, but that's okay. 878 return Sema::TDK_Success; 879 } 880 case TemplateArgument::Pack: 881 assert(0 && "FIXME: Implement!"); 882 break; 883 } 884 885 return Sema::TDK_Success; 886} 887 888static Sema::TemplateDeductionResult 889DeduceTemplateArguments(Sema &S, 890 TemplateParameterList *TemplateParams, 891 const TemplateArgumentList &ParamList, 892 const TemplateArgumentList &ArgList, 893 Sema::TemplateDeductionInfo &Info, 894 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 895 assert(ParamList.size() == ArgList.size()); 896 for (unsigned I = 0, N = ParamList.size(); I != N; ++I) { 897 if (Sema::TemplateDeductionResult Result 898 = DeduceTemplateArguments(S, TemplateParams, 899 ParamList[I], ArgList[I], 900 Info, Deduced)) 901 return Result; 902 } 903 return Sema::TDK_Success; 904} 905 906/// \brief Determine whether two template arguments are the same. 907static bool isSameTemplateArg(ASTContext &Context, 908 const TemplateArgument &X, 909 const TemplateArgument &Y) { 910 if (X.getKind() != Y.getKind()) 911 return false; 912 913 switch (X.getKind()) { 914 case TemplateArgument::Null: 915 assert(false && "Comparing NULL template argument"); 916 break; 917 918 case TemplateArgument::Type: 919 return Context.getCanonicalType(X.getAsType()) == 920 Context.getCanonicalType(Y.getAsType()); 921 922 case TemplateArgument::Declaration: 923 return X.getAsDecl()->getCanonicalDecl() == 924 Y.getAsDecl()->getCanonicalDecl(); 925 926 case TemplateArgument::Template: 927 return Context.getCanonicalTemplateName(X.getAsTemplate()) 928 .getAsVoidPointer() == 929 Context.getCanonicalTemplateName(Y.getAsTemplate()) 930 .getAsVoidPointer(); 931 932 case TemplateArgument::Integral: 933 return *X.getAsIntegral() == *Y.getAsIntegral(); 934 935 case TemplateArgument::Expression: { 936 llvm::FoldingSetNodeID XID, YID; 937 X.getAsExpr()->Profile(XID, Context, true); 938 Y.getAsExpr()->Profile(YID, Context, true); 939 return XID == YID; 940 } 941 942 case TemplateArgument::Pack: 943 if (X.pack_size() != Y.pack_size()) 944 return false; 945 946 for (TemplateArgument::pack_iterator XP = X.pack_begin(), 947 XPEnd = X.pack_end(), 948 YP = Y.pack_begin(); 949 XP != XPEnd; ++XP, ++YP) 950 if (!isSameTemplateArg(Context, *XP, *YP)) 951 return false; 952 953 return true; 954 } 955 956 return false; 957} 958 959/// \brief Helper function to build a TemplateParameter when we don't 960/// know its type statically. 961static TemplateParameter makeTemplateParameter(Decl *D) { 962 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D)) 963 return TemplateParameter(TTP); 964 else if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) 965 return TemplateParameter(NTTP); 966 967 return TemplateParameter(cast<TemplateTemplateParmDecl>(D)); 968} 969 970/// Complete template argument deduction for a class template partial 971/// specialization. 972static Sema::TemplateDeductionResult 973FinishTemplateArgumentDeduction(Sema &S, 974 ClassTemplatePartialSpecializationDecl *Partial, 975 const TemplateArgumentList &TemplateArgs, 976 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 977 Sema::TemplateDeductionInfo &Info) { 978 // Trap errors. 979 Sema::SFINAETrap Trap(S); 980 981 Sema::ContextRAII SavedContext(S, Partial); 982 983 // C++ [temp.deduct.type]p2: 984 // [...] or if any template argument remains neither deduced nor 985 // explicitly specified, template argument deduction fails. 986 TemplateArgumentListBuilder Builder(Partial->getTemplateParameters(), 987 Deduced.size()); 988 for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { 989 if (Deduced[I].isNull()) { 990 Decl *Param 991 = const_cast<NamedDecl *>( 992 Partial->getTemplateParameters()->getParam(I)); 993 Info.Param = makeTemplateParameter(Param); 994 return Sema::TDK_Incomplete; 995 } 996 997 Builder.Append(Deduced[I]); 998 } 999 1000 // Form the template argument list from the deduced template arguments. 1001 TemplateArgumentList *DeducedArgumentList 1002 = new (S.Context) TemplateArgumentList(S.Context, Builder, 1003 /*TakeArgs=*/true); 1004 Info.reset(DeducedArgumentList); 1005 1006 // Substitute the deduced template arguments into the template 1007 // arguments of the class template partial specialization, and 1008 // verify that the instantiated template arguments are both valid 1009 // and are equivalent to the template arguments originally provided 1010 // to the class template. 1011 // FIXME: Do we have to correct the types of deduced non-type template 1012 // arguments (in particular, integral non-type template arguments?). 1013 Sema::LocalInstantiationScope InstScope(S); 1014 ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); 1015 const TemplateArgumentLoc *PartialTemplateArgs 1016 = Partial->getTemplateArgsAsWritten(); 1017 unsigned N = Partial->getNumTemplateArgsAsWritten(); 1018 1019 // Note that we don't provide the langle and rangle locations. 1020 TemplateArgumentListInfo InstArgs; 1021 1022 for (unsigned I = 0; I != N; ++I) { 1023 Decl *Param = const_cast<NamedDecl *>( 1024 ClassTemplate->getTemplateParameters()->getParam(I)); 1025 TemplateArgumentLoc InstArg; 1026 if (S.Subst(PartialTemplateArgs[I], InstArg, 1027 MultiLevelTemplateArgumentList(*DeducedArgumentList))) { 1028 Info.Param = makeTemplateParameter(Param); 1029 Info.FirstArg = PartialTemplateArgs[I].getArgument(); 1030 return Sema::TDK_SubstitutionFailure; 1031 } 1032 InstArgs.addArgument(InstArg); 1033 } 1034 1035 TemplateArgumentListBuilder ConvertedInstArgs( 1036 ClassTemplate->getTemplateParameters(), N); 1037 1038 if (S.CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(), 1039 InstArgs, false, ConvertedInstArgs)) 1040 return Sema::TDK_SubstitutionFailure; 1041 1042 for (unsigned I = 0, E = ConvertedInstArgs.flatSize(); I != E; ++I) { 1043 TemplateArgument InstArg = ConvertedInstArgs.getFlatArguments()[I]; 1044 1045 Decl *Param = const_cast<NamedDecl *>( 1046 ClassTemplate->getTemplateParameters()->getParam(I)); 1047 1048 if (InstArg.getKind() == TemplateArgument::Expression) { 1049 // When the argument is an expression, check the expression result 1050 // against the actual template parameter to get down to the canonical 1051 // template argument. 1052 Expr *InstExpr = InstArg.getAsExpr(); 1053 if (NonTypeTemplateParmDecl *NTTP 1054 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 1055 if (S.CheckTemplateArgument(NTTP, NTTP->getType(), InstExpr, InstArg)) { 1056 Info.Param = makeTemplateParameter(Param); 1057 Info.FirstArg = Partial->getTemplateArgs()[I]; 1058 return Sema::TDK_SubstitutionFailure; 1059 } 1060 } 1061 } 1062 1063 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) { 1064 Info.Param = makeTemplateParameter(Param); 1065 Info.FirstArg = TemplateArgs[I]; 1066 Info.SecondArg = InstArg; 1067 return Sema::TDK_NonDeducedMismatch; 1068 } 1069 } 1070 1071 if (Trap.hasErrorOccurred()) 1072 return Sema::TDK_SubstitutionFailure; 1073 1074 return Sema::TDK_Success; 1075} 1076 1077/// \brief Perform template argument deduction to determine whether 1078/// the given template arguments match the given class template 1079/// partial specialization per C++ [temp.class.spec.match]. 1080Sema::TemplateDeductionResult 1081Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, 1082 const TemplateArgumentList &TemplateArgs, 1083 TemplateDeductionInfo &Info) { 1084 // C++ [temp.class.spec.match]p2: 1085 // A partial specialization matches a given actual template 1086 // argument list if the template arguments of the partial 1087 // specialization can be deduced from the actual template argument 1088 // list (14.8.2). 1089 SFINAETrap Trap(*this); 1090 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1091 Deduced.resize(Partial->getTemplateParameters()->size()); 1092 if (TemplateDeductionResult Result 1093 = ::DeduceTemplateArguments(*this, 1094 Partial->getTemplateParameters(), 1095 Partial->getTemplateArgs(), 1096 TemplateArgs, Info, Deduced)) 1097 return Result; 1098 1099 InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, 1100 Deduced.data(), Deduced.size()); 1101 if (Inst) 1102 return TDK_InstantiationDepth; 1103 1104 if (Trap.hasErrorOccurred()) 1105 return Sema::TDK_SubstitutionFailure; 1106 1107 return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs, 1108 Deduced, Info); 1109} 1110 1111/// \brief Determine whether the given type T is a simple-template-id type. 1112static bool isSimpleTemplateIdType(QualType T) { 1113 if (const TemplateSpecializationType *Spec 1114 = T->getAs<TemplateSpecializationType>()) 1115 return Spec->getTemplateName().getAsTemplateDecl() != 0; 1116 1117 return false; 1118} 1119 1120/// \brief Substitute the explicitly-provided template arguments into the 1121/// given function template according to C++ [temp.arg.explicit]. 1122/// 1123/// \param FunctionTemplate the function template into which the explicit 1124/// template arguments will be substituted. 1125/// 1126/// \param ExplicitTemplateArguments the explicitly-specified template 1127/// arguments. 1128/// 1129/// \param Deduced the deduced template arguments, which will be populated 1130/// with the converted and checked explicit template arguments. 1131/// 1132/// \param ParamTypes will be populated with the instantiated function 1133/// parameters. 1134/// 1135/// \param FunctionType if non-NULL, the result type of the function template 1136/// will also be instantiated and the pointed-to value will be updated with 1137/// the instantiated function type. 1138/// 1139/// \param Info if substitution fails for any reason, this object will be 1140/// populated with more information about the failure. 1141/// 1142/// \returns TDK_Success if substitution was successful, or some failure 1143/// condition. 1144Sema::TemplateDeductionResult 1145Sema::SubstituteExplicitTemplateArguments( 1146 FunctionTemplateDecl *FunctionTemplate, 1147 const TemplateArgumentListInfo &ExplicitTemplateArgs, 1148 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1149 llvm::SmallVectorImpl<QualType> &ParamTypes, 1150 QualType *FunctionType, 1151 TemplateDeductionInfo &Info) { 1152 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1153 TemplateParameterList *TemplateParams 1154 = FunctionTemplate->getTemplateParameters(); 1155 1156 if (ExplicitTemplateArgs.size() == 0) { 1157 // No arguments to substitute; just copy over the parameter types and 1158 // fill in the function type. 1159 for (FunctionDecl::param_iterator P = Function->param_begin(), 1160 PEnd = Function->param_end(); 1161 P != PEnd; 1162 ++P) 1163 ParamTypes.push_back((*P)->getType()); 1164 1165 if (FunctionType) 1166 *FunctionType = Function->getType(); 1167 return TDK_Success; 1168 } 1169 1170 // Substitution of the explicit template arguments into a function template 1171 /// is a SFINAE context. Trap any errors that might occur. 1172 SFINAETrap Trap(*this); 1173 1174 // C++ [temp.arg.explicit]p3: 1175 // Template arguments that are present shall be specified in the 1176 // declaration order of their corresponding template-parameters. The 1177 // template argument list shall not specify more template-arguments than 1178 // there are corresponding template-parameters. 1179 TemplateArgumentListBuilder Builder(TemplateParams, 1180 ExplicitTemplateArgs.size()); 1181 1182 // Enter a new template instantiation context where we check the 1183 // explicitly-specified template arguments against this function template, 1184 // and then substitute them into the function parameter types. 1185 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 1186 FunctionTemplate, Deduced.data(), Deduced.size(), 1187 ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution); 1188 if (Inst) 1189 return TDK_InstantiationDepth; 1190 1191 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 1192 1193 if (CheckTemplateArgumentList(FunctionTemplate, 1194 SourceLocation(), 1195 ExplicitTemplateArgs, 1196 true, 1197 Builder) || Trap.hasErrorOccurred()) { 1198 unsigned Index = Builder.structuredSize(); 1199 if (Index >= TemplateParams->size()) 1200 Index = TemplateParams->size() - 1; 1201 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index)); 1202 return TDK_InvalidExplicitArguments; 1203 } 1204 1205 // Form the template argument list from the explicitly-specified 1206 // template arguments. 1207 TemplateArgumentList *ExplicitArgumentList 1208 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1209 Info.reset(ExplicitArgumentList); 1210 1211 // Instantiate the types of each of the function parameters given the 1212 // explicitly-specified template arguments. 1213 for (FunctionDecl::param_iterator P = Function->param_begin(), 1214 PEnd = Function->param_end(); 1215 P != PEnd; 1216 ++P) { 1217 QualType ParamType 1218 = SubstType((*P)->getType(), 1219 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 1220 (*P)->getLocation(), (*P)->getDeclName()); 1221 if (ParamType.isNull() || Trap.hasErrorOccurred()) 1222 return TDK_SubstitutionFailure; 1223 1224 ParamTypes.push_back(ParamType); 1225 } 1226 1227 // If the caller wants a full function type back, instantiate the return 1228 // type and form that function type. 1229 if (FunctionType) { 1230 // FIXME: exception-specifications? 1231 const FunctionProtoType *Proto 1232 = Function->getType()->getAs<FunctionProtoType>(); 1233 assert(Proto && "Function template does not have a prototype?"); 1234 1235 QualType ResultType 1236 = SubstType(Proto->getResultType(), 1237 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 1238 Function->getTypeSpecStartLoc(), 1239 Function->getDeclName()); 1240 if (ResultType.isNull() || Trap.hasErrorOccurred()) 1241 return TDK_SubstitutionFailure; 1242 1243 *FunctionType = BuildFunctionType(ResultType, 1244 ParamTypes.data(), ParamTypes.size(), 1245 Proto->isVariadic(), 1246 Proto->getTypeQuals(), 1247 Function->getLocation(), 1248 Function->getDeclName()); 1249 if (FunctionType->isNull() || Trap.hasErrorOccurred()) 1250 return TDK_SubstitutionFailure; 1251 } 1252 1253 // C++ [temp.arg.explicit]p2: 1254 // Trailing template arguments that can be deduced (14.8.2) may be 1255 // omitted from the list of explicit template-arguments. If all of the 1256 // template arguments can be deduced, they may all be omitted; in this 1257 // case, the empty template argument list <> itself may also be omitted. 1258 // 1259 // Take all of the explicitly-specified arguments and put them into the 1260 // set of deduced template arguments. 1261 Deduced.reserve(TemplateParams->size()); 1262 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) 1263 Deduced.push_back(ExplicitArgumentList->get(I)); 1264 1265 return TDK_Success; 1266} 1267 1268/// \brief Allocate a TemplateArgumentLoc where all locations have 1269/// been initialized to the given location. 1270/// 1271/// \param S The semantic analysis object. 1272/// 1273/// \param The template argument we are producing template argument 1274/// location information for. 1275/// 1276/// \param NTTPType For a declaration template argument, the type of 1277/// the non-type template parameter that corresponds to this template 1278/// argument. 1279/// 1280/// \param Loc The source location to use for the resulting template 1281/// argument. 1282static TemplateArgumentLoc 1283getTrivialTemplateArgumentLoc(Sema &S, 1284 const TemplateArgument &Arg, 1285 QualType NTTPType, 1286 SourceLocation Loc) { 1287 switch (Arg.getKind()) { 1288 case TemplateArgument::Null: 1289 llvm_unreachable("Can't get a NULL template argument here"); 1290 break; 1291 1292 case TemplateArgument::Type: 1293 return TemplateArgumentLoc(Arg, 1294 S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); 1295 1296 case TemplateArgument::Declaration: { 1297 Expr *E 1298 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 1299 .takeAs<Expr>(); 1300 return TemplateArgumentLoc(TemplateArgument(E), E); 1301 } 1302 1303 case TemplateArgument::Integral: { 1304 Expr *E 1305 = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>(); 1306 return TemplateArgumentLoc(TemplateArgument(E), E); 1307 } 1308 1309 case TemplateArgument::Template: 1310 return TemplateArgumentLoc(Arg, SourceRange(), Loc); 1311 1312 case TemplateArgument::Expression: 1313 return TemplateArgumentLoc(Arg, Arg.getAsExpr()); 1314 1315 case TemplateArgument::Pack: 1316 llvm_unreachable("Template parameter packs are not yet supported"); 1317 } 1318 1319 return TemplateArgumentLoc(); 1320} 1321 1322/// \brief Finish template argument deduction for a function template, 1323/// checking the deduced template arguments for completeness and forming 1324/// the function template specialization. 1325Sema::TemplateDeductionResult 1326Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate, 1327 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1328 unsigned NumExplicitlySpecified, 1329 FunctionDecl *&Specialization, 1330 TemplateDeductionInfo &Info) { 1331 TemplateParameterList *TemplateParams 1332 = FunctionTemplate->getTemplateParameters(); 1333 1334 // Template argument deduction for function templates in a SFINAE context. 1335 // Trap any errors that might occur. 1336 SFINAETrap Trap(*this); 1337 1338 // Enter a new template instantiation context while we instantiate the 1339 // actual function declaration. 1340 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 1341 FunctionTemplate, Deduced.data(), Deduced.size(), 1342 ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution); 1343 if (Inst) 1344 return TDK_InstantiationDepth; 1345 1346 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 1347 1348 // C++ [temp.deduct.type]p2: 1349 // [...] or if any template argument remains neither deduced nor 1350 // explicitly specified, template argument deduction fails. 1351 TemplateArgumentListBuilder Builder(TemplateParams, Deduced.size()); 1352 for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { 1353 NamedDecl *Param = FunctionTemplate->getTemplateParameters()->getParam(I); 1354 if (!Deduced[I].isNull()) { 1355 if (I < NumExplicitlySpecified || 1356 Deduced[I].getKind() == TemplateArgument::Type) { 1357 // We have already fully type-checked and converted this 1358 // argument (because it was explicitly-specified) or no 1359 // additional checking is necessary (because it's a template 1360 // type parameter). Just record the presence of this 1361 // parameter. 1362 Builder.Append(Deduced[I]); 1363 continue; 1364 } 1365 1366 // We have deduced this argument, so it still needs to be 1367 // checked and converted. 1368 1369 // First, for a non-type template parameter type that is 1370 // initialized by a declaration, we need the type of the 1371 // corresponding non-type template parameter. 1372 QualType NTTPType; 1373 if (NonTypeTemplateParmDecl *NTTP 1374 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 1375 if (Deduced[I].getKind() == TemplateArgument::Declaration) { 1376 NTTPType = NTTP->getType(); 1377 if (NTTPType->isDependentType()) { 1378 TemplateArgumentList TemplateArgs(Context, Builder, 1379 /*TakeArgs=*/false); 1380 NTTPType = SubstType(NTTPType, 1381 MultiLevelTemplateArgumentList(TemplateArgs), 1382 NTTP->getLocation(), 1383 NTTP->getDeclName()); 1384 if (NTTPType.isNull()) { 1385 Info.Param = makeTemplateParameter(Param); 1386 Info.reset(new (Context) TemplateArgumentList(Context, Builder, 1387 /*TakeArgs=*/true)); 1388 return TDK_SubstitutionFailure; 1389 } 1390 } 1391 } 1392 } 1393 1394 // Convert the deduced template argument into a template 1395 // argument that we can check, almost as if the user had written 1396 // the template argument explicitly. 1397 TemplateArgumentLoc Arg = getTrivialTemplateArgumentLoc(*this, 1398 Deduced[I], 1399 NTTPType, 1400 SourceLocation()); 1401 1402 // Check the template argument, converting it as necessary. 1403 if (CheckTemplateArgument(Param, Arg, 1404 FunctionTemplate, 1405 FunctionTemplate->getLocation(), 1406 FunctionTemplate->getSourceRange().getEnd(), 1407 Builder, 1408 Deduced[I].wasDeducedFromArrayBound() 1409 ? CTAK_DeducedFromArrayBound 1410 : CTAK_Deduced)) { 1411 Info.Param = makeTemplateParameter( 1412 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1413 Info.reset(new (Context) TemplateArgumentList(Context, Builder, 1414 /*TakeArgs=*/true)); 1415 return TDK_SubstitutionFailure; 1416 } 1417 1418 continue; 1419 } 1420 1421 // Substitute into the default template argument, if available. 1422 TemplateArgumentLoc DefArg 1423 = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate, 1424 FunctionTemplate->getLocation(), 1425 FunctionTemplate->getSourceRange().getEnd(), 1426 Param, 1427 Builder); 1428 1429 // If there was no default argument, deduction is incomplete. 1430 if (DefArg.getArgument().isNull()) { 1431 Info.Param = makeTemplateParameter( 1432 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1433 return TDK_Incomplete; 1434 } 1435 1436 // Check whether we can actually use the default argument. 1437 if (CheckTemplateArgument(Param, DefArg, 1438 FunctionTemplate, 1439 FunctionTemplate->getLocation(), 1440 FunctionTemplate->getSourceRange().getEnd(), 1441 Builder, 1442 CTAK_Deduced)) { 1443 Info.Param = makeTemplateParameter( 1444 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1445 Info.reset(new (Context) TemplateArgumentList(Context, Builder, 1446 /*TakeArgs=*/true)); 1447 return TDK_SubstitutionFailure; 1448 } 1449 1450 // If we get here, we successfully used the default template argument. 1451 } 1452 1453 // Form the template argument list from the deduced template arguments. 1454 TemplateArgumentList *DeducedArgumentList 1455 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1456 Info.reset(DeducedArgumentList); 1457 1458 // Substitute the deduced template arguments into the function template 1459 // declaration to produce the function template specialization. 1460 DeclContext *Owner = FunctionTemplate->getDeclContext(); 1461 if (FunctionTemplate->getFriendObjectKind()) 1462 Owner = FunctionTemplate->getLexicalDeclContext(); 1463 Specialization = cast_or_null<FunctionDecl>( 1464 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, 1465 MultiLevelTemplateArgumentList(*DeducedArgumentList))); 1466 if (!Specialization) 1467 return TDK_SubstitutionFailure; 1468 1469 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() == 1470 FunctionTemplate->getCanonicalDecl()); 1471 1472 // If the template argument list is owned by the function template 1473 // specialization, release it. 1474 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList && 1475 !Trap.hasErrorOccurred()) 1476 Info.take(); 1477 1478 // There may have been an error that did not prevent us from constructing a 1479 // declaration. Mark the declaration invalid and return with a substitution 1480 // failure. 1481 if (Trap.hasErrorOccurred()) { 1482 Specialization->setInvalidDecl(true); 1483 return TDK_SubstitutionFailure; 1484 } 1485 1486 return TDK_Success; 1487} 1488 1489static QualType GetTypeOfFunction(ASTContext &Context, 1490 bool isAddressOfOperand, 1491 FunctionDecl *Fn) { 1492 if (!isAddressOfOperand) return Fn->getType(); 1493 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) 1494 if (Method->isInstance()) 1495 return Context.getMemberPointerType(Fn->getType(), 1496 Context.getTypeDeclType(Method->getParent()).getTypePtr()); 1497 return Context.getPointerType(Fn->getType()); 1498} 1499 1500/// Apply the deduction rules for overload sets. 1501/// 1502/// \return the null type if this argument should be treated as an 1503/// undeduced context 1504static QualType 1505ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, 1506 Expr *Arg, QualType ParamType) { 1507 llvm::PointerIntPair<OverloadExpr*,1> R = OverloadExpr::find(Arg); 1508 1509 bool isAddressOfOperand = bool(R.getInt()); 1510 OverloadExpr *Ovl = R.getPointer(); 1511 1512 // If there were explicit template arguments, we can only find 1513 // something via C++ [temp.arg.explicit]p3, i.e. if the arguments 1514 // unambiguously name a full specialization. 1515 if (Ovl->hasExplicitTemplateArgs()) { 1516 // But we can still look for an explicit specialization. 1517 if (FunctionDecl *ExplicitSpec 1518 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 1519 return GetTypeOfFunction(S.Context, isAddressOfOperand, ExplicitSpec); 1520 return QualType(); 1521 } 1522 1523 // C++0x [temp.deduct.call]p6: 1524 // When P is a function type, pointer to function type, or pointer 1525 // to member function type: 1526 1527 if (!ParamType->isFunctionType() && 1528 !ParamType->isFunctionPointerType() && 1529 !ParamType->isMemberFunctionPointerType()) 1530 return QualType(); 1531 1532 QualType Match; 1533 for (UnresolvedSetIterator I = Ovl->decls_begin(), 1534 E = Ovl->decls_end(); I != E; ++I) { 1535 NamedDecl *D = (*I)->getUnderlyingDecl(); 1536 1537 // - If the argument is an overload set containing one or more 1538 // function templates, the parameter is treated as a 1539 // non-deduced context. 1540 if (isa<FunctionTemplateDecl>(D)) 1541 return QualType(); 1542 1543 FunctionDecl *Fn = cast<FunctionDecl>(D); 1544 QualType ArgType = GetTypeOfFunction(S.Context, isAddressOfOperand, Fn); 1545 1546 // - If the argument is an overload set (not containing function 1547 // templates), trial argument deduction is attempted using each 1548 // of the members of the set. If deduction succeeds for only one 1549 // of the overload set members, that member is used as the 1550 // argument value for the deduction. If deduction succeeds for 1551 // more than one member of the overload set the parameter is 1552 // treated as a non-deduced context. 1553 1554 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 1555 // Type deduction is done independently for each P/A pair, and 1556 // the deduced template argument values are then combined. 1557 // So we do not reject deductions which were made elsewhere. 1558 llvm::SmallVector<DeducedTemplateArgument, 8> 1559 Deduced(TemplateParams->size()); 1560 Sema::TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 1561 unsigned TDF = 0; 1562 1563 Sema::TemplateDeductionResult Result 1564 = DeduceTemplateArguments(S, TemplateParams, 1565 ParamType, ArgType, 1566 Info, Deduced, TDF); 1567 if (Result) continue; 1568 if (!Match.isNull()) return QualType(); 1569 Match = ArgType; 1570 } 1571 1572 return Match; 1573} 1574 1575/// \brief Perform template argument deduction from a function call 1576/// (C++ [temp.deduct.call]). 1577/// 1578/// \param FunctionTemplate the function template for which we are performing 1579/// template argument deduction. 1580/// 1581/// \param ExplicitTemplateArguments the explicit template arguments provided 1582/// for this call. 1583/// 1584/// \param Args the function call arguments 1585/// 1586/// \param NumArgs the number of arguments in Args 1587/// 1588/// \param Name the name of the function being called. This is only significant 1589/// when the function template is a conversion function template, in which 1590/// case this routine will also perform template argument deduction based on 1591/// the function to which 1592/// 1593/// \param Specialization if template argument deduction was successful, 1594/// this will be set to the function template specialization produced by 1595/// template argument deduction. 1596/// 1597/// \param Info the argument will be updated to provide additional information 1598/// about template argument deduction. 1599/// 1600/// \returns the result of template argument deduction. 1601Sema::TemplateDeductionResult 1602Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1603 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1604 Expr **Args, unsigned NumArgs, 1605 FunctionDecl *&Specialization, 1606 TemplateDeductionInfo &Info) { 1607 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1608 1609 // C++ [temp.deduct.call]p1: 1610 // Template argument deduction is done by comparing each function template 1611 // parameter type (call it P) with the type of the corresponding argument 1612 // of the call (call it A) as described below. 1613 unsigned CheckArgs = NumArgs; 1614 if (NumArgs < Function->getMinRequiredArguments()) 1615 return TDK_TooFewArguments; 1616 else if (NumArgs > Function->getNumParams()) { 1617 const FunctionProtoType *Proto 1618 = Function->getType()->getAs<FunctionProtoType>(); 1619 if (!Proto->isVariadic()) 1620 return TDK_TooManyArguments; 1621 1622 CheckArgs = Function->getNumParams(); 1623 } 1624 1625 // The types of the parameters from which we will perform template argument 1626 // deduction. 1627 Sema::LocalInstantiationScope InstScope(*this); 1628 TemplateParameterList *TemplateParams 1629 = FunctionTemplate->getTemplateParameters(); 1630 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1631 llvm::SmallVector<QualType, 4> ParamTypes; 1632 unsigned NumExplicitlySpecified = 0; 1633 if (ExplicitTemplateArgs) { 1634 TemplateDeductionResult Result = 1635 SubstituteExplicitTemplateArguments(FunctionTemplate, 1636 *ExplicitTemplateArgs, 1637 Deduced, 1638 ParamTypes, 1639 0, 1640 Info); 1641 if (Result) 1642 return Result; 1643 1644 NumExplicitlySpecified = Deduced.size(); 1645 } else { 1646 // Just fill in the parameter types from the function declaration. 1647 for (unsigned I = 0; I != CheckArgs; ++I) 1648 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 1649 } 1650 1651 // Deduce template arguments from the function parameters. 1652 Deduced.resize(TemplateParams->size()); 1653 for (unsigned I = 0; I != CheckArgs; ++I) { 1654 QualType ParamType = ParamTypes[I]; 1655 QualType ArgType = Args[I]->getType(); 1656 1657 // Overload sets usually make this parameter an undeduced 1658 // context, but there are sometimes special circumstances. 1659 if (ArgType == Context.OverloadTy) { 1660 ArgType = ResolveOverloadForDeduction(*this, TemplateParams, 1661 Args[I], ParamType); 1662 if (ArgType.isNull()) 1663 continue; 1664 } 1665 1666 // C++ [temp.deduct.call]p2: 1667 // If P is not a reference type: 1668 QualType CanonParamType = Context.getCanonicalType(ParamType); 1669 bool ParamWasReference = isa<ReferenceType>(CanonParamType); 1670 if (!ParamWasReference) { 1671 // - If A is an array type, the pointer type produced by the 1672 // array-to-pointer standard conversion (4.2) is used in place of 1673 // A for type deduction; otherwise, 1674 if (ArgType->isArrayType()) 1675 ArgType = Context.getArrayDecayedType(ArgType); 1676 // - If A is a function type, the pointer type produced by the 1677 // function-to-pointer standard conversion (4.3) is used in place 1678 // of A for type deduction; otherwise, 1679 else if (ArgType->isFunctionType()) 1680 ArgType = Context.getPointerType(ArgType); 1681 else { 1682 // - If A is a cv-qualified type, the top level cv-qualifiers of A’s 1683 // type are ignored for type deduction. 1684 QualType CanonArgType = Context.getCanonicalType(ArgType); 1685 if (CanonArgType.getLocalCVRQualifiers()) 1686 ArgType = CanonArgType.getLocalUnqualifiedType(); 1687 } 1688 } 1689 1690 // C++0x [temp.deduct.call]p3: 1691 // If P is a cv-qualified type, the top level cv-qualifiers of P’s type 1692 // are ignored for type deduction. 1693 if (CanonParamType.getLocalCVRQualifiers()) 1694 ParamType = CanonParamType.getLocalUnqualifiedType(); 1695 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) { 1696 // [...] If P is a reference type, the type referred to by P is used 1697 // for type deduction. 1698 ParamType = ParamRefType->getPointeeType(); 1699 1700 // [...] If P is of the form T&&, where T is a template parameter, and 1701 // the argument is an lvalue, the type A& is used in place of A for 1702 // type deduction. 1703 if (isa<RValueReferenceType>(ParamRefType) && 1704 ParamRefType->getAs<TemplateTypeParmType>() && 1705 Args[I]->isLvalue(Context) == Expr::LV_Valid) 1706 ArgType = Context.getLValueReferenceType(ArgType); 1707 } 1708 1709 // C++0x [temp.deduct.call]p4: 1710 // In general, the deduction process attempts to find template argument 1711 // values that will make the deduced A identical to A (after the type A 1712 // is transformed as described above). [...] 1713 unsigned TDF = TDF_SkipNonDependent; 1714 1715 // - If the original P is a reference type, the deduced A (i.e., the 1716 // type referred to by the reference) can be more cv-qualified than 1717 // the transformed A. 1718 if (ParamWasReference) 1719 TDF |= TDF_ParamWithReferenceType; 1720 // - The transformed A can be another pointer or pointer to member 1721 // type that can be converted to the deduced A via a qualification 1722 // conversion (4.4). 1723 if (ArgType->isPointerType() || ArgType->isMemberPointerType()) 1724 TDF |= TDF_IgnoreQualifiers; 1725 // - If P is a class and P has the form simple-template-id, then the 1726 // transformed A can be a derived class of the deduced A. Likewise, 1727 // if P is a pointer to a class of the form simple-template-id, the 1728 // transformed A can be a pointer to a derived class pointed to by 1729 // the deduced A. 1730 if (isSimpleTemplateIdType(ParamType) || 1731 (isa<PointerType>(ParamType) && 1732 isSimpleTemplateIdType( 1733 ParamType->getAs<PointerType>()->getPointeeType()))) 1734 TDF |= TDF_DerivedClass; 1735 1736 if (TemplateDeductionResult Result 1737 = ::DeduceTemplateArguments(*this, TemplateParams, 1738 ParamType, ArgType, Info, Deduced, 1739 TDF)) 1740 return Result; 1741 1742 // FIXME: we need to check that the deduced A is the same as A, 1743 // modulo the various allowed differences. 1744 } 1745 1746 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 1747 NumExplicitlySpecified, 1748 Specialization, Info); 1749} 1750 1751/// \brief Deduce template arguments when taking the address of a function 1752/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 1753/// a template. 1754/// 1755/// \param FunctionTemplate the function template for which we are performing 1756/// template argument deduction. 1757/// 1758/// \param ExplicitTemplateArguments the explicitly-specified template 1759/// arguments. 1760/// 1761/// \param ArgFunctionType the function type that will be used as the 1762/// "argument" type (A) when performing template argument deduction from the 1763/// function template's function type. This type may be NULL, if there is no 1764/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 1765/// 1766/// \param Specialization if template argument deduction was successful, 1767/// this will be set to the function template specialization produced by 1768/// template argument deduction. 1769/// 1770/// \param Info the argument will be updated to provide additional information 1771/// about template argument deduction. 1772/// 1773/// \returns the result of template argument deduction. 1774Sema::TemplateDeductionResult 1775Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1776 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1777 QualType ArgFunctionType, 1778 FunctionDecl *&Specialization, 1779 TemplateDeductionInfo &Info) { 1780 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1781 TemplateParameterList *TemplateParams 1782 = FunctionTemplate->getTemplateParameters(); 1783 QualType FunctionType = Function->getType(); 1784 1785 // Substitute any explicit template arguments. 1786 Sema::LocalInstantiationScope InstScope(*this); 1787 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1788 unsigned NumExplicitlySpecified = 0; 1789 llvm::SmallVector<QualType, 4> ParamTypes; 1790 if (ExplicitTemplateArgs) { 1791 if (TemplateDeductionResult Result 1792 = SubstituteExplicitTemplateArguments(FunctionTemplate, 1793 *ExplicitTemplateArgs, 1794 Deduced, ParamTypes, 1795 &FunctionType, Info)) 1796 return Result; 1797 1798 NumExplicitlySpecified = Deduced.size(); 1799 } 1800 1801 // Template argument deduction for function templates in a SFINAE context. 1802 // Trap any errors that might occur. 1803 SFINAETrap Trap(*this); 1804 1805 Deduced.resize(TemplateParams->size()); 1806 1807 if (!ArgFunctionType.isNull()) { 1808 // Deduce template arguments from the function type. 1809 if (TemplateDeductionResult Result 1810 = ::DeduceTemplateArguments(*this, TemplateParams, 1811 FunctionType, ArgFunctionType, Info, 1812 Deduced, 0)) 1813 return Result; 1814 } 1815 1816 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 1817 NumExplicitlySpecified, 1818 Specialization, Info); 1819} 1820 1821/// \brief Deduce template arguments for a templated conversion 1822/// function (C++ [temp.deduct.conv]) and, if successful, produce a 1823/// conversion function template specialization. 1824Sema::TemplateDeductionResult 1825Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1826 QualType ToType, 1827 CXXConversionDecl *&Specialization, 1828 TemplateDeductionInfo &Info) { 1829 CXXConversionDecl *Conv 1830 = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()); 1831 QualType FromType = Conv->getConversionType(); 1832 1833 // Canonicalize the types for deduction. 1834 QualType P = Context.getCanonicalType(FromType); 1835 QualType A = Context.getCanonicalType(ToType); 1836 1837 // C++0x [temp.deduct.conv]p3: 1838 // If P is a reference type, the type referred to by P is used for 1839 // type deduction. 1840 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 1841 P = PRef->getPointeeType(); 1842 1843 // C++0x [temp.deduct.conv]p3: 1844 // If A is a reference type, the type referred to by A is used 1845 // for type deduction. 1846 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 1847 A = ARef->getPointeeType(); 1848 // C++ [temp.deduct.conv]p2: 1849 // 1850 // If A is not a reference type: 1851 else { 1852 assert(!A->isReferenceType() && "Reference types were handled above"); 1853 1854 // - If P is an array type, the pointer type produced by the 1855 // array-to-pointer standard conversion (4.2) is used in place 1856 // of P for type deduction; otherwise, 1857 if (P->isArrayType()) 1858 P = Context.getArrayDecayedType(P); 1859 // - If P is a function type, the pointer type produced by the 1860 // function-to-pointer standard conversion (4.3) is used in 1861 // place of P for type deduction; otherwise, 1862 else if (P->isFunctionType()) 1863 P = Context.getPointerType(P); 1864 // - If P is a cv-qualified type, the top level cv-qualifiers of 1865 // P’s type are ignored for type deduction. 1866 else 1867 P = P.getUnqualifiedType(); 1868 1869 // C++0x [temp.deduct.conv]p3: 1870 // If A is a cv-qualified type, the top level cv-qualifiers of A’s 1871 // type are ignored for type deduction. 1872 A = A.getUnqualifiedType(); 1873 } 1874 1875 // Template argument deduction for function templates in a SFINAE context. 1876 // Trap any errors that might occur. 1877 SFINAETrap Trap(*this); 1878 1879 // C++ [temp.deduct.conv]p1: 1880 // Template argument deduction is done by comparing the return 1881 // type of the template conversion function (call it P) with the 1882 // type that is required as the result of the conversion (call it 1883 // A) as described in 14.8.2.4. 1884 TemplateParameterList *TemplateParams 1885 = FunctionTemplate->getTemplateParameters(); 1886 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1887 Deduced.resize(TemplateParams->size()); 1888 1889 // C++0x [temp.deduct.conv]p4: 1890 // In general, the deduction process attempts to find template 1891 // argument values that will make the deduced A identical to 1892 // A. However, there are two cases that allow a difference: 1893 unsigned TDF = 0; 1894 // - If the original A is a reference type, A can be more 1895 // cv-qualified than the deduced A (i.e., the type referred to 1896 // by the reference) 1897 if (ToType->isReferenceType()) 1898 TDF |= TDF_ParamWithReferenceType; 1899 // - The deduced A can be another pointer or pointer to member 1900 // type that can be converted to A via a qualification 1901 // conversion. 1902 // 1903 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 1904 // both P and A are pointers or member pointers. In this case, we 1905 // just ignore cv-qualifiers completely). 1906 if ((P->isPointerType() && A->isPointerType()) || 1907 (P->isMemberPointerType() && P->isMemberPointerType())) 1908 TDF |= TDF_IgnoreQualifiers; 1909 if (TemplateDeductionResult Result 1910 = ::DeduceTemplateArguments(*this, TemplateParams, 1911 P, A, Info, Deduced, TDF)) 1912 return Result; 1913 1914 // FIXME: we need to check that the deduced A is the same as A, 1915 // modulo the various allowed differences. 1916 1917 // Finish template argument deduction. 1918 Sema::LocalInstantiationScope InstScope(*this); 1919 FunctionDecl *Spec = 0; 1920 TemplateDeductionResult Result 1921 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, 1922 Info); 1923 Specialization = cast_or_null<CXXConversionDecl>(Spec); 1924 return Result; 1925} 1926 1927/// \brief Deduce template arguments for a function template when there is 1928/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 1929/// 1930/// \param FunctionTemplate the function template for which we are performing 1931/// template argument deduction. 1932/// 1933/// \param ExplicitTemplateArguments the explicitly-specified template 1934/// arguments. 1935/// 1936/// \param Specialization if template argument deduction was successful, 1937/// this will be set to the function template specialization produced by 1938/// template argument deduction. 1939/// 1940/// \param Info the argument will be updated to provide additional information 1941/// about template argument deduction. 1942/// 1943/// \returns the result of template argument deduction. 1944Sema::TemplateDeductionResult 1945Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1946 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1947 FunctionDecl *&Specialization, 1948 TemplateDeductionInfo &Info) { 1949 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 1950 QualType(), Specialization, Info); 1951} 1952 1953/// \brief Stores the result of comparing the qualifiers of two types. 1954enum DeductionQualifierComparison { 1955 NeitherMoreQualified = 0, 1956 ParamMoreQualified, 1957 ArgMoreQualified 1958}; 1959 1960/// \brief Deduce the template arguments during partial ordering by comparing 1961/// the parameter type and the argument type (C++0x [temp.deduct.partial]). 1962/// 1963/// \param S the semantic analysis object within which we are deducing 1964/// 1965/// \param TemplateParams the template parameters that we are deducing 1966/// 1967/// \param ParamIn the parameter type 1968/// 1969/// \param ArgIn the argument type 1970/// 1971/// \param Info information about the template argument deduction itself 1972/// 1973/// \param Deduced the deduced template arguments 1974/// 1975/// \returns the result of template argument deduction so far. Note that a 1976/// "success" result means that template argument deduction has not yet failed, 1977/// but it may still fail, later, for other reasons. 1978static Sema::TemplateDeductionResult 1979DeduceTemplateArgumentsDuringPartialOrdering(Sema &S, 1980 TemplateParameterList *TemplateParams, 1981 QualType ParamIn, QualType ArgIn, 1982 Sema::TemplateDeductionInfo &Info, 1983 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1984 llvm::SmallVectorImpl<DeductionQualifierComparison> *QualifierComparisons) { 1985 CanQualType Param = S.Context.getCanonicalType(ParamIn); 1986 CanQualType Arg = S.Context.getCanonicalType(ArgIn); 1987 1988 // C++0x [temp.deduct.partial]p5: 1989 // Before the partial ordering is done, certain transformations are 1990 // performed on the types used for partial ordering: 1991 // - If P is a reference type, P is replaced by the type referred to. 1992 CanQual<ReferenceType> ParamRef = Param->getAs<ReferenceType>(); 1993 if (!ParamRef.isNull()) 1994 Param = ParamRef->getPointeeType(); 1995 1996 // - If A is a reference type, A is replaced by the type referred to. 1997 CanQual<ReferenceType> ArgRef = Arg->getAs<ReferenceType>(); 1998 if (!ArgRef.isNull()) 1999 Arg = ArgRef->getPointeeType(); 2000 2001 if (QualifierComparisons && !ParamRef.isNull() && !ArgRef.isNull()) { 2002 // C++0x [temp.deduct.partial]p6: 2003 // If both P and A were reference types (before being replaced with the 2004 // type referred to above), determine which of the two types (if any) is 2005 // more cv-qualified than the other; otherwise the types are considered to 2006 // be equally cv-qualified for partial ordering purposes. The result of this 2007 // determination will be used below. 2008 // 2009 // We save this information for later, using it only when deduction 2010 // succeeds in both directions. 2011 DeductionQualifierComparison QualifierResult = NeitherMoreQualified; 2012 if (Param.isMoreQualifiedThan(Arg)) 2013 QualifierResult = ParamMoreQualified; 2014 else if (Arg.isMoreQualifiedThan(Param)) 2015 QualifierResult = ArgMoreQualified; 2016 QualifierComparisons->push_back(QualifierResult); 2017 } 2018 2019 // C++0x [temp.deduct.partial]p7: 2020 // Remove any top-level cv-qualifiers: 2021 // - If P is a cv-qualified type, P is replaced by the cv-unqualified 2022 // version of P. 2023 Param = Param.getUnqualifiedType(); 2024 // - If A is a cv-qualified type, A is replaced by the cv-unqualified 2025 // version of A. 2026 Arg = Arg.getUnqualifiedType(); 2027 2028 // C++0x [temp.deduct.partial]p8: 2029 // Using the resulting types P and A the deduction is then done as 2030 // described in 14.9.2.5. If deduction succeeds for a given type, the type 2031 // from the argument template is considered to be at least as specialized 2032 // as the type from the parameter template. 2033 return DeduceTemplateArguments(S, TemplateParams, Param, Arg, Info, 2034 Deduced, TDF_None); 2035} 2036 2037static void 2038MarkUsedTemplateParameters(Sema &SemaRef, QualType T, 2039 bool OnlyDeduced, 2040 unsigned Level, 2041 llvm::SmallVectorImpl<bool> &Deduced); 2042 2043/// \brief Determine whether the function template \p FT1 is at least as 2044/// specialized as \p FT2. 2045static bool isAtLeastAsSpecializedAs(Sema &S, 2046 SourceLocation Loc, 2047 FunctionTemplateDecl *FT1, 2048 FunctionTemplateDecl *FT2, 2049 TemplatePartialOrderingContext TPOC, 2050 llvm::SmallVectorImpl<DeductionQualifierComparison> *QualifierComparisons) { 2051 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 2052 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 2053 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 2054 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 2055 2056 assert(Proto1 && Proto2 && "Function templates must have prototypes"); 2057 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 2058 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 2059 Deduced.resize(TemplateParams->size()); 2060 2061 // C++0x [temp.deduct.partial]p3: 2062 // The types used to determine the ordering depend on the context in which 2063 // the partial ordering is done: 2064 Sema::TemplateDeductionInfo Info(S.Context, Loc); 2065 switch (TPOC) { 2066 case TPOC_Call: { 2067 // - In the context of a function call, the function parameter types are 2068 // used. 2069 unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); 2070 for (unsigned I = 0; I != NumParams; ++I) 2071 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2072 TemplateParams, 2073 Proto2->getArgType(I), 2074 Proto1->getArgType(I), 2075 Info, 2076 Deduced, 2077 QualifierComparisons)) 2078 return false; 2079 2080 break; 2081 } 2082 2083 case TPOC_Conversion: 2084 // - In the context of a call to a conversion operator, the return types 2085 // of the conversion function templates are used. 2086 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2087 TemplateParams, 2088 Proto2->getResultType(), 2089 Proto1->getResultType(), 2090 Info, 2091 Deduced, 2092 QualifierComparisons)) 2093 return false; 2094 break; 2095 2096 case TPOC_Other: 2097 // - In other contexts (14.6.6.2) the function template’s function type 2098 // is used. 2099 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2100 TemplateParams, 2101 FD2->getType(), 2102 FD1->getType(), 2103 Info, 2104 Deduced, 2105 QualifierComparisons)) 2106 return false; 2107 break; 2108 } 2109 2110 // C++0x [temp.deduct.partial]p11: 2111 // In most cases, all template parameters must have values in order for 2112 // deduction to succeed, but for partial ordering purposes a template 2113 // parameter may remain without a value provided it is not used in the 2114 // types being used for partial ordering. [ Note: a template parameter used 2115 // in a non-deduced context is considered used. -end note] 2116 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 2117 for (; ArgIdx != NumArgs; ++ArgIdx) 2118 if (Deduced[ArgIdx].isNull()) 2119 break; 2120 2121 if (ArgIdx == NumArgs) { 2122 // All template arguments were deduced. FT1 is at least as specialized 2123 // as FT2. 2124 return true; 2125 } 2126 2127 // Figure out which template parameters were used. 2128 llvm::SmallVector<bool, 4> UsedParameters; 2129 UsedParameters.resize(TemplateParams->size()); 2130 switch (TPOC) { 2131 case TPOC_Call: { 2132 unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); 2133 for (unsigned I = 0; I != NumParams; ++I) 2134 ::MarkUsedTemplateParameters(S, Proto2->getArgType(I), false, 2135 TemplateParams->getDepth(), 2136 UsedParameters); 2137 break; 2138 } 2139 2140 case TPOC_Conversion: 2141 ::MarkUsedTemplateParameters(S, Proto2->getResultType(), false, 2142 TemplateParams->getDepth(), 2143 UsedParameters); 2144 break; 2145 2146 case TPOC_Other: 2147 ::MarkUsedTemplateParameters(S, FD2->getType(), false, 2148 TemplateParams->getDepth(), 2149 UsedParameters); 2150 break; 2151 } 2152 2153 for (; ArgIdx != NumArgs; ++ArgIdx) 2154 // If this argument had no value deduced but was used in one of the types 2155 // used for partial ordering, then deduction fails. 2156 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 2157 return false; 2158 2159 return true; 2160} 2161 2162 2163/// \brief Returns the more specialized function template according 2164/// to the rules of function template partial ordering (C++ [temp.func.order]). 2165/// 2166/// \param FT1 the first function template 2167/// 2168/// \param FT2 the second function template 2169/// 2170/// \param TPOC the context in which we are performing partial ordering of 2171/// function templates. 2172/// 2173/// \returns the more specialized function template. If neither 2174/// template is more specialized, returns NULL. 2175FunctionTemplateDecl * 2176Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 2177 FunctionTemplateDecl *FT2, 2178 SourceLocation Loc, 2179 TemplatePartialOrderingContext TPOC) { 2180 llvm::SmallVector<DeductionQualifierComparison, 4> QualifierComparisons; 2181 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 0); 2182 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 2183 &QualifierComparisons); 2184 2185 if (Better1 != Better2) // We have a clear winner 2186 return Better1? FT1 : FT2; 2187 2188 if (!Better1 && !Better2) // Neither is better than the other 2189 return 0; 2190 2191 2192 // C++0x [temp.deduct.partial]p10: 2193 // If for each type being considered a given template is at least as 2194 // specialized for all types and more specialized for some set of types and 2195 // the other template is not more specialized for any types or is not at 2196 // least as specialized for any types, then the given template is more 2197 // specialized than the other template. Otherwise, neither template is more 2198 // specialized than the other. 2199 Better1 = false; 2200 Better2 = false; 2201 for (unsigned I = 0, N = QualifierComparisons.size(); I != N; ++I) { 2202 // C++0x [temp.deduct.partial]p9: 2203 // If, for a given type, deduction succeeds in both directions (i.e., the 2204 // types are identical after the transformations above) and if the type 2205 // from the argument template is more cv-qualified than the type from the 2206 // parameter template (as described above) that type is considered to be 2207 // more specialized than the other. If neither type is more cv-qualified 2208 // than the other then neither type is more specialized than the other. 2209 switch (QualifierComparisons[I]) { 2210 case NeitherMoreQualified: 2211 break; 2212 2213 case ParamMoreQualified: 2214 Better1 = true; 2215 if (Better2) 2216 return 0; 2217 break; 2218 2219 case ArgMoreQualified: 2220 Better2 = true; 2221 if (Better1) 2222 return 0; 2223 break; 2224 } 2225 } 2226 2227 assert(!(Better1 && Better2) && "Should have broken out in the loop above"); 2228 if (Better1) 2229 return FT1; 2230 else if (Better2) 2231 return FT2; 2232 else 2233 return 0; 2234} 2235 2236/// \brief Determine if the two templates are equivalent. 2237static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 2238 if (T1 == T2) 2239 return true; 2240 2241 if (!T1 || !T2) 2242 return false; 2243 2244 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 2245} 2246 2247/// \brief Retrieve the most specialized of the given function template 2248/// specializations. 2249/// 2250/// \param SpecBegin the start iterator of the function template 2251/// specializations that we will be comparing. 2252/// 2253/// \param SpecEnd the end iterator of the function template 2254/// specializations, paired with \p SpecBegin. 2255/// 2256/// \param TPOC the partial ordering context to use to compare the function 2257/// template specializations. 2258/// 2259/// \param Loc the location where the ambiguity or no-specializations 2260/// diagnostic should occur. 2261/// 2262/// \param NoneDiag partial diagnostic used to diagnose cases where there are 2263/// no matching candidates. 2264/// 2265/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 2266/// occurs. 2267/// 2268/// \param CandidateDiag partial diagnostic used for each function template 2269/// specialization that is a candidate in the ambiguous ordering. One parameter 2270/// in this diagnostic should be unbound, which will correspond to the string 2271/// describing the template arguments for the function template specialization. 2272/// 2273/// \param Index if non-NULL and the result of this function is non-nULL, 2274/// receives the index corresponding to the resulting function template 2275/// specialization. 2276/// 2277/// \returns the most specialized function template specialization, if 2278/// found. Otherwise, returns SpecEnd. 2279/// 2280/// \todo FIXME: Consider passing in the "also-ran" candidates that failed 2281/// template argument deduction. 2282UnresolvedSetIterator 2283Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, 2284 UnresolvedSetIterator SpecEnd, 2285 TemplatePartialOrderingContext TPOC, 2286 SourceLocation Loc, 2287 const PartialDiagnostic &NoneDiag, 2288 const PartialDiagnostic &AmbigDiag, 2289 const PartialDiagnostic &CandidateDiag) { 2290 if (SpecBegin == SpecEnd) { 2291 Diag(Loc, NoneDiag); 2292 return SpecEnd; 2293 } 2294 2295 if (SpecBegin + 1 == SpecEnd) 2296 return SpecBegin; 2297 2298 // Find the function template that is better than all of the templates it 2299 // has been compared to. 2300 UnresolvedSetIterator Best = SpecBegin; 2301 FunctionTemplateDecl *BestTemplate 2302 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 2303 assert(BestTemplate && "Not a function template specialization?"); 2304 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 2305 FunctionTemplateDecl *Challenger 2306 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 2307 assert(Challenger && "Not a function template specialization?"); 2308 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 2309 Loc, TPOC), 2310 Challenger)) { 2311 Best = I; 2312 BestTemplate = Challenger; 2313 } 2314 } 2315 2316 // Make sure that the "best" function template is more specialized than all 2317 // of the others. 2318 bool Ambiguous = false; 2319 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 2320 FunctionTemplateDecl *Challenger 2321 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 2322 if (I != Best && 2323 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 2324 Loc, TPOC), 2325 BestTemplate)) { 2326 Ambiguous = true; 2327 break; 2328 } 2329 } 2330 2331 if (!Ambiguous) { 2332 // We found an answer. Return it. 2333 return Best; 2334 } 2335 2336 // Diagnose the ambiguity. 2337 Diag(Loc, AmbigDiag); 2338 2339 // FIXME: Can we order the candidates in some sane way? 2340 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) 2341 Diag((*I)->getLocation(), CandidateDiag) 2342 << getTemplateArgumentBindingsText( 2343 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(), 2344 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs()); 2345 2346 return SpecEnd; 2347} 2348 2349/// \brief Returns the more specialized class template partial specialization 2350/// according to the rules of partial ordering of class template partial 2351/// specializations (C++ [temp.class.order]). 2352/// 2353/// \param PS1 the first class template partial specialization 2354/// 2355/// \param PS2 the second class template partial specialization 2356/// 2357/// \returns the more specialized class template partial specialization. If 2358/// neither partial specialization is more specialized, returns NULL. 2359ClassTemplatePartialSpecializationDecl * 2360Sema::getMoreSpecializedPartialSpecialization( 2361 ClassTemplatePartialSpecializationDecl *PS1, 2362 ClassTemplatePartialSpecializationDecl *PS2, 2363 SourceLocation Loc) { 2364 // C++ [temp.class.order]p1: 2365 // For two class template partial specializations, the first is at least as 2366 // specialized as the second if, given the following rewrite to two 2367 // function templates, the first function template is at least as 2368 // specialized as the second according to the ordering rules for function 2369 // templates (14.6.6.2): 2370 // - the first function template has the same template parameters as the 2371 // first partial specialization and has a single function parameter 2372 // whose type is a class template specialization with the template 2373 // arguments of the first partial specialization, and 2374 // - the second function template has the same template parameters as the 2375 // second partial specialization and has a single function parameter 2376 // whose type is a class template specialization with the template 2377 // arguments of the second partial specialization. 2378 // 2379 // Rather than synthesize function templates, we merely perform the 2380 // equivalent partial ordering by performing deduction directly on 2381 // the template arguments of the class template partial 2382 // specializations. This computation is slightly simpler than the 2383 // general problem of function template partial ordering, because 2384 // class template partial specializations are more constrained. We 2385 // know that every template parameter is deducible from the class 2386 // template partial specialization's template arguments, for 2387 // example. 2388 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 2389 Sema::TemplateDeductionInfo Info(Context, Loc); 2390 2391 QualType PT1 = PS1->getInjectedSpecializationType(); 2392 QualType PT2 = PS2->getInjectedSpecializationType(); 2393 2394 // Determine whether PS1 is at least as specialized as PS2 2395 Deduced.resize(PS2->getTemplateParameters()->size()); 2396 bool Better1 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, 2397 PS2->getTemplateParameters(), 2398 PT2, 2399 PT1, 2400 Info, 2401 Deduced, 2402 0); 2403 if (Better1) 2404 Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, 2405 PS1->getTemplateArgs(), 2406 Deduced, Info); 2407 2408 // Determine whether PS2 is at least as specialized as PS1 2409 Deduced.clear(); 2410 Deduced.resize(PS1->getTemplateParameters()->size()); 2411 bool Better2 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, 2412 PS1->getTemplateParameters(), 2413 PT1, 2414 PT2, 2415 Info, 2416 Deduced, 2417 0); 2418 if (Better2) 2419 Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, 2420 PS2->getTemplateArgs(), 2421 Deduced, Info); 2422 2423 if (Better1 == Better2) 2424 return 0; 2425 2426 return Better1? PS1 : PS2; 2427} 2428 2429static void 2430MarkUsedTemplateParameters(Sema &SemaRef, 2431 const TemplateArgument &TemplateArg, 2432 bool OnlyDeduced, 2433 unsigned Depth, 2434 llvm::SmallVectorImpl<bool> &Used); 2435 2436/// \brief Mark the template parameters that are used by the given 2437/// expression. 2438static void 2439MarkUsedTemplateParameters(Sema &SemaRef, 2440 const Expr *E, 2441 bool OnlyDeduced, 2442 unsigned Depth, 2443 llvm::SmallVectorImpl<bool> &Used) { 2444 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to 2445 // find other occurrences of template parameters. 2446 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E); 2447 if (!DRE) 2448 return; 2449 2450 const NonTypeTemplateParmDecl *NTTP 2451 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 2452 if (!NTTP) 2453 return; 2454 2455 if (NTTP->getDepth() == Depth) 2456 Used[NTTP->getIndex()] = true; 2457} 2458 2459/// \brief Mark the template parameters that are used by the given 2460/// nested name specifier. 2461static void 2462MarkUsedTemplateParameters(Sema &SemaRef, 2463 NestedNameSpecifier *NNS, 2464 bool OnlyDeduced, 2465 unsigned Depth, 2466 llvm::SmallVectorImpl<bool> &Used) { 2467 if (!NNS) 2468 return; 2469 2470 MarkUsedTemplateParameters(SemaRef, NNS->getPrefix(), OnlyDeduced, Depth, 2471 Used); 2472 MarkUsedTemplateParameters(SemaRef, QualType(NNS->getAsType(), 0), 2473 OnlyDeduced, Depth, Used); 2474} 2475 2476/// \brief Mark the template parameters that are used by the given 2477/// template name. 2478static void 2479MarkUsedTemplateParameters(Sema &SemaRef, 2480 TemplateName Name, 2481 bool OnlyDeduced, 2482 unsigned Depth, 2483 llvm::SmallVectorImpl<bool> &Used) { 2484 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 2485 if (TemplateTemplateParmDecl *TTP 2486 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 2487 if (TTP->getDepth() == Depth) 2488 Used[TTP->getIndex()] = true; 2489 } 2490 return; 2491 } 2492 2493 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 2494 MarkUsedTemplateParameters(SemaRef, QTN->getQualifier(), OnlyDeduced, 2495 Depth, Used); 2496 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 2497 MarkUsedTemplateParameters(SemaRef, DTN->getQualifier(), OnlyDeduced, 2498 Depth, Used); 2499} 2500 2501/// \brief Mark the template parameters that are used by the given 2502/// type. 2503static void 2504MarkUsedTemplateParameters(Sema &SemaRef, QualType T, 2505 bool OnlyDeduced, 2506 unsigned Depth, 2507 llvm::SmallVectorImpl<bool> &Used) { 2508 if (T.isNull()) 2509 return; 2510 2511 // Non-dependent types have nothing deducible 2512 if (!T->isDependentType()) 2513 return; 2514 2515 T = SemaRef.Context.getCanonicalType(T); 2516 switch (T->getTypeClass()) { 2517 case Type::Pointer: 2518 MarkUsedTemplateParameters(SemaRef, 2519 cast<PointerType>(T)->getPointeeType(), 2520 OnlyDeduced, 2521 Depth, 2522 Used); 2523 break; 2524 2525 case Type::BlockPointer: 2526 MarkUsedTemplateParameters(SemaRef, 2527 cast<BlockPointerType>(T)->getPointeeType(), 2528 OnlyDeduced, 2529 Depth, 2530 Used); 2531 break; 2532 2533 case Type::LValueReference: 2534 case Type::RValueReference: 2535 MarkUsedTemplateParameters(SemaRef, 2536 cast<ReferenceType>(T)->getPointeeType(), 2537 OnlyDeduced, 2538 Depth, 2539 Used); 2540 break; 2541 2542 case Type::MemberPointer: { 2543 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 2544 MarkUsedTemplateParameters(SemaRef, MemPtr->getPointeeType(), OnlyDeduced, 2545 Depth, Used); 2546 MarkUsedTemplateParameters(SemaRef, QualType(MemPtr->getClass(), 0), 2547 OnlyDeduced, Depth, Used); 2548 break; 2549 } 2550 2551 case Type::DependentSizedArray: 2552 MarkUsedTemplateParameters(SemaRef, 2553 cast<DependentSizedArrayType>(T)->getSizeExpr(), 2554 OnlyDeduced, Depth, Used); 2555 // Fall through to check the element type 2556 2557 case Type::ConstantArray: 2558 case Type::IncompleteArray: 2559 MarkUsedTemplateParameters(SemaRef, 2560 cast<ArrayType>(T)->getElementType(), 2561 OnlyDeduced, Depth, Used); 2562 break; 2563 2564 case Type::Vector: 2565 case Type::ExtVector: 2566 MarkUsedTemplateParameters(SemaRef, 2567 cast<VectorType>(T)->getElementType(), 2568 OnlyDeduced, Depth, Used); 2569 break; 2570 2571 case Type::DependentSizedExtVector: { 2572 const DependentSizedExtVectorType *VecType 2573 = cast<DependentSizedExtVectorType>(T); 2574 MarkUsedTemplateParameters(SemaRef, VecType->getElementType(), OnlyDeduced, 2575 Depth, Used); 2576 MarkUsedTemplateParameters(SemaRef, VecType->getSizeExpr(), OnlyDeduced, 2577 Depth, Used); 2578 break; 2579 } 2580 2581 case Type::FunctionProto: { 2582 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 2583 MarkUsedTemplateParameters(SemaRef, Proto->getResultType(), OnlyDeduced, 2584 Depth, Used); 2585 for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) 2586 MarkUsedTemplateParameters(SemaRef, Proto->getArgType(I), OnlyDeduced, 2587 Depth, Used); 2588 break; 2589 } 2590 2591 case Type::TemplateTypeParm: { 2592 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 2593 if (TTP->getDepth() == Depth) 2594 Used[TTP->getIndex()] = true; 2595 break; 2596 } 2597 2598 case Type::InjectedClassName: 2599 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 2600 // fall through 2601 2602 case Type::TemplateSpecialization: { 2603 const TemplateSpecializationType *Spec 2604 = cast<TemplateSpecializationType>(T); 2605 MarkUsedTemplateParameters(SemaRef, Spec->getTemplateName(), OnlyDeduced, 2606 Depth, Used); 2607 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 2608 MarkUsedTemplateParameters(SemaRef, Spec->getArg(I), OnlyDeduced, Depth, 2609 Used); 2610 break; 2611 } 2612 2613 case Type::Complex: 2614 if (!OnlyDeduced) 2615 MarkUsedTemplateParameters(SemaRef, 2616 cast<ComplexType>(T)->getElementType(), 2617 OnlyDeduced, Depth, Used); 2618 break; 2619 2620 case Type::DependentName: 2621 if (!OnlyDeduced) 2622 MarkUsedTemplateParameters(SemaRef, 2623 cast<DependentNameType>(T)->getQualifier(), 2624 OnlyDeduced, Depth, Used); 2625 break; 2626 2627 case Type::DependentTemplateSpecialization: { 2628 const DependentTemplateSpecializationType *Spec 2629 = cast<DependentTemplateSpecializationType>(T); 2630 if (!OnlyDeduced) 2631 MarkUsedTemplateParameters(SemaRef, Spec->getQualifier(), 2632 OnlyDeduced, Depth, Used); 2633 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 2634 MarkUsedTemplateParameters(SemaRef, Spec->getArg(I), OnlyDeduced, Depth, 2635 Used); 2636 break; 2637 } 2638 2639 case Type::TypeOf: 2640 if (!OnlyDeduced) 2641 MarkUsedTemplateParameters(SemaRef, 2642 cast<TypeOfType>(T)->getUnderlyingType(), 2643 OnlyDeduced, Depth, Used); 2644 break; 2645 2646 case Type::TypeOfExpr: 2647 if (!OnlyDeduced) 2648 MarkUsedTemplateParameters(SemaRef, 2649 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 2650 OnlyDeduced, Depth, Used); 2651 break; 2652 2653 case Type::Decltype: 2654 if (!OnlyDeduced) 2655 MarkUsedTemplateParameters(SemaRef, 2656 cast<DecltypeType>(T)->getUnderlyingExpr(), 2657 OnlyDeduced, Depth, Used); 2658 break; 2659 2660 // None of these types have any template parameters in them. 2661 case Type::Builtin: 2662 case Type::VariableArray: 2663 case Type::FunctionNoProto: 2664 case Type::Record: 2665 case Type::Enum: 2666 case Type::ObjCInterface: 2667 case Type::ObjCObject: 2668 case Type::ObjCObjectPointer: 2669 case Type::UnresolvedUsing: 2670#define TYPE(Class, Base) 2671#define ABSTRACT_TYPE(Class, Base) 2672#define DEPENDENT_TYPE(Class, Base) 2673#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 2674#include "clang/AST/TypeNodes.def" 2675 break; 2676 } 2677} 2678 2679/// \brief Mark the template parameters that are used by this 2680/// template argument. 2681static void 2682MarkUsedTemplateParameters(Sema &SemaRef, 2683 const TemplateArgument &TemplateArg, 2684 bool OnlyDeduced, 2685 unsigned Depth, 2686 llvm::SmallVectorImpl<bool> &Used) { 2687 switch (TemplateArg.getKind()) { 2688 case TemplateArgument::Null: 2689 case TemplateArgument::Integral: 2690 case TemplateArgument::Declaration: 2691 break; 2692 2693 case TemplateArgument::Type: 2694 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsType(), OnlyDeduced, 2695 Depth, Used); 2696 break; 2697 2698 case TemplateArgument::Template: 2699 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsTemplate(), 2700 OnlyDeduced, Depth, Used); 2701 break; 2702 2703 case TemplateArgument::Expression: 2704 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsExpr(), OnlyDeduced, 2705 Depth, Used); 2706 break; 2707 2708 case TemplateArgument::Pack: 2709 for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), 2710 PEnd = TemplateArg.pack_end(); 2711 P != PEnd; ++P) 2712 MarkUsedTemplateParameters(SemaRef, *P, OnlyDeduced, Depth, Used); 2713 break; 2714 } 2715} 2716 2717/// \brief Mark the template parameters can be deduced by the given 2718/// template argument list. 2719/// 2720/// \param TemplateArgs the template argument list from which template 2721/// parameters will be deduced. 2722/// 2723/// \param Deduced a bit vector whose elements will be set to \c true 2724/// to indicate when the corresponding template parameter will be 2725/// deduced. 2726void 2727Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 2728 bool OnlyDeduced, unsigned Depth, 2729 llvm::SmallVectorImpl<bool> &Used) { 2730 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 2731 ::MarkUsedTemplateParameters(*this, TemplateArgs[I], OnlyDeduced, 2732 Depth, Used); 2733} 2734 2735/// \brief Marks all of the template parameters that will be deduced by a 2736/// call to the given function template. 2737void 2738Sema::MarkDeducedTemplateParameters(FunctionTemplateDecl *FunctionTemplate, 2739 llvm::SmallVectorImpl<bool> &Deduced) { 2740 TemplateParameterList *TemplateParams 2741 = FunctionTemplate->getTemplateParameters(); 2742 Deduced.clear(); 2743 Deduced.resize(TemplateParams->size()); 2744 2745 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2746 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 2747 ::MarkUsedTemplateParameters(*this, Function->getParamDecl(I)->getType(), 2748 true, TemplateParams->getDepth(), Deduced); 2749} 2750