SemaTemplateDeduction.cpp revision a101c324ac9a53b114a4f6698df169bddf9d6084
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 const PointerType *PointerArg = Arg->getAs<PointerType>(); 486 if (!PointerArg) 487 return Sema::TDK_NonDeducedMismatch; 488 489 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass); 490 return DeduceTemplateArguments(S, TemplateParams, 491 cast<PointerType>(Param)->getPointeeType(), 492 PointerArg->getPointeeType(), 493 Info, Deduced, SubTDF); 494 } 495 496 // T & 497 case Type::LValueReference: { 498 const LValueReferenceType *ReferenceArg = Arg->getAs<LValueReferenceType>(); 499 if (!ReferenceArg) 500 return Sema::TDK_NonDeducedMismatch; 501 502 return DeduceTemplateArguments(S, TemplateParams, 503 cast<LValueReferenceType>(Param)->getPointeeType(), 504 ReferenceArg->getPointeeType(), 505 Info, Deduced, 0); 506 } 507 508 // T && [C++0x] 509 case Type::RValueReference: { 510 const RValueReferenceType *ReferenceArg = Arg->getAs<RValueReferenceType>(); 511 if (!ReferenceArg) 512 return Sema::TDK_NonDeducedMismatch; 513 514 return DeduceTemplateArguments(S, TemplateParams, 515 cast<RValueReferenceType>(Param)->getPointeeType(), 516 ReferenceArg->getPointeeType(), 517 Info, Deduced, 0); 518 } 519 520 // T [] (implied, but not stated explicitly) 521 case Type::IncompleteArray: { 522 const IncompleteArrayType *IncompleteArrayArg = 523 S.Context.getAsIncompleteArrayType(Arg); 524 if (!IncompleteArrayArg) 525 return Sema::TDK_NonDeducedMismatch; 526 527 return DeduceTemplateArguments(S, TemplateParams, 528 S.Context.getAsIncompleteArrayType(Param)->getElementType(), 529 IncompleteArrayArg->getElementType(), 530 Info, Deduced, 0); 531 } 532 533 // T [integer-constant] 534 case Type::ConstantArray: { 535 const ConstantArrayType *ConstantArrayArg = 536 S.Context.getAsConstantArrayType(Arg); 537 if (!ConstantArrayArg) 538 return Sema::TDK_NonDeducedMismatch; 539 540 const ConstantArrayType *ConstantArrayParm = 541 S.Context.getAsConstantArrayType(Param); 542 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize()) 543 return Sema::TDK_NonDeducedMismatch; 544 545 return DeduceTemplateArguments(S, TemplateParams, 546 ConstantArrayParm->getElementType(), 547 ConstantArrayArg->getElementType(), 548 Info, Deduced, 0); 549 } 550 551 // type [i] 552 case Type::DependentSizedArray: { 553 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg); 554 if (!ArrayArg) 555 return Sema::TDK_NonDeducedMismatch; 556 557 // Check the element type of the arrays 558 const DependentSizedArrayType *DependentArrayParm 559 = S.Context.getAsDependentSizedArrayType(Param); 560 if (Sema::TemplateDeductionResult Result 561 = DeduceTemplateArguments(S, TemplateParams, 562 DependentArrayParm->getElementType(), 563 ArrayArg->getElementType(), 564 Info, Deduced, 0)) 565 return Result; 566 567 // Determine the array bound is something we can deduce. 568 NonTypeTemplateParmDecl *NTTP 569 = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr()); 570 if (!NTTP) 571 return Sema::TDK_Success; 572 573 // We can perform template argument deduction for the given non-type 574 // template parameter. 575 assert(NTTP->getDepth() == 0 && 576 "Cannot deduce non-type template argument at depth > 0"); 577 if (const ConstantArrayType *ConstantArrayArg 578 = dyn_cast<ConstantArrayType>(ArrayArg)) { 579 llvm::APSInt Size(ConstantArrayArg->getSize()); 580 return DeduceNonTypeTemplateArgument(S, NTTP, Size, 581 S.Context.getSizeType(), 582 /*ArrayBound=*/true, 583 Info, Deduced); 584 } 585 if (const DependentSizedArrayType *DependentArrayArg 586 = dyn_cast<DependentSizedArrayType>(ArrayArg)) 587 return DeduceNonTypeTemplateArgument(S, NTTP, 588 DependentArrayArg->getSizeExpr(), 589 Info, Deduced); 590 591 // Incomplete type does not match a dependently-sized array type 592 return Sema::TDK_NonDeducedMismatch; 593 } 594 595 // type(*)(T) 596 // T(*)() 597 // T(*)(T) 598 case Type::FunctionProto: { 599 const FunctionProtoType *FunctionProtoArg = 600 dyn_cast<FunctionProtoType>(Arg); 601 if (!FunctionProtoArg) 602 return Sema::TDK_NonDeducedMismatch; 603 604 const FunctionProtoType *FunctionProtoParam = 605 cast<FunctionProtoType>(Param); 606 607 if (FunctionProtoParam->getTypeQuals() != 608 FunctionProtoArg->getTypeQuals()) 609 return Sema::TDK_NonDeducedMismatch; 610 611 if (FunctionProtoParam->getNumArgs() != FunctionProtoArg->getNumArgs()) 612 return Sema::TDK_NonDeducedMismatch; 613 614 if (FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic()) 615 return Sema::TDK_NonDeducedMismatch; 616 617 // Check return types. 618 if (Sema::TemplateDeductionResult Result 619 = DeduceTemplateArguments(S, TemplateParams, 620 FunctionProtoParam->getResultType(), 621 FunctionProtoArg->getResultType(), 622 Info, Deduced, 0)) 623 return Result; 624 625 for (unsigned I = 0, N = FunctionProtoParam->getNumArgs(); I != N; ++I) { 626 // Check argument types. 627 if (Sema::TemplateDeductionResult Result 628 = DeduceTemplateArguments(S, TemplateParams, 629 FunctionProtoParam->getArgType(I), 630 FunctionProtoArg->getArgType(I), 631 Info, Deduced, 0)) 632 return Result; 633 } 634 635 return Sema::TDK_Success; 636 } 637 638 case Type::InjectedClassName: { 639 // Treat a template's injected-class-name as if the template 640 // specialization type had been used. 641 Param = cast<InjectedClassNameType>(Param) 642 ->getInjectedSpecializationType(); 643 assert(isa<TemplateSpecializationType>(Param) && 644 "injected class name is not a template specialization type"); 645 // fall through 646 } 647 648 // template-name<T> (where template-name refers to a class template) 649 // template-name<i> 650 // TT<T> 651 // TT<i> 652 // TT<> 653 case Type::TemplateSpecialization: { 654 const TemplateSpecializationType *SpecParam 655 = cast<TemplateSpecializationType>(Param); 656 657 // Try to deduce template arguments from the template-id. 658 Sema::TemplateDeductionResult Result 659 = DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, 660 Info, Deduced); 661 662 if (Result && (TDF & TDF_DerivedClass)) { 663 // C++ [temp.deduct.call]p3b3: 664 // If P is a class, and P has the form template-id, then A can be a 665 // derived class of the deduced A. Likewise, if P is a pointer to a 666 // class of the form template-id, A can be a pointer to a derived 667 // class pointed to by the deduced A. 668 // 669 // More importantly: 670 // These alternatives are considered only if type deduction would 671 // otherwise fail. 672 if (const RecordType *RecordT = Arg->getAs<RecordType>()) { 673 // We cannot inspect base classes as part of deduction when the type 674 // is incomplete, so either instantiate any templates necessary to 675 // complete the type, or skip over it if it cannot be completed. 676 if (S.RequireCompleteType(Info.getLocation(), Arg, 0)) 677 return Result; 678 679 // Use data recursion to crawl through the list of base classes. 680 // Visited contains the set of nodes we have already visited, while 681 // ToVisit is our stack of records that we still need to visit. 682 llvm::SmallPtrSet<const RecordType *, 8> Visited; 683 llvm::SmallVector<const RecordType *, 8> ToVisit; 684 ToVisit.push_back(RecordT); 685 bool Successful = false; 686 while (!ToVisit.empty()) { 687 // Retrieve the next class in the inheritance hierarchy. 688 const RecordType *NextT = ToVisit.back(); 689 ToVisit.pop_back(); 690 691 // If we have already seen this type, skip it. 692 if (!Visited.insert(NextT)) 693 continue; 694 695 // If this is a base class, try to perform template argument 696 // deduction from it. 697 if (NextT != RecordT) { 698 Sema::TemplateDeductionResult BaseResult 699 = DeduceTemplateArguments(S, TemplateParams, SpecParam, 700 QualType(NextT, 0), Info, Deduced); 701 702 // If template argument deduction for this base was successful, 703 // note that we had some success. 704 if (BaseResult == Sema::TDK_Success) 705 Successful = true; 706 } 707 708 // Visit base classes 709 CXXRecordDecl *Next = cast<CXXRecordDecl>(NextT->getDecl()); 710 for (CXXRecordDecl::base_class_iterator Base = Next->bases_begin(), 711 BaseEnd = Next->bases_end(); 712 Base != BaseEnd; ++Base) { 713 assert(Base->getType()->isRecordType() && 714 "Base class that isn't a record?"); 715 ToVisit.push_back(Base->getType()->getAs<RecordType>()); 716 } 717 } 718 719 if (Successful) 720 return Sema::TDK_Success; 721 } 722 723 } 724 725 return Result; 726 } 727 728 // T type::* 729 // T T::* 730 // T (type::*)() 731 // type (T::*)() 732 // type (type::*)(T) 733 // type (T::*)(T) 734 // T (type::*)(T) 735 // T (T::*)() 736 // T (T::*)(T) 737 case Type::MemberPointer: { 738 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param); 739 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg); 740 if (!MemPtrArg) 741 return Sema::TDK_NonDeducedMismatch; 742 743 if (Sema::TemplateDeductionResult Result 744 = DeduceTemplateArguments(S, TemplateParams, 745 MemPtrParam->getPointeeType(), 746 MemPtrArg->getPointeeType(), 747 Info, Deduced, 748 TDF & TDF_IgnoreQualifiers)) 749 return Result; 750 751 return DeduceTemplateArguments(S, TemplateParams, 752 QualType(MemPtrParam->getClass(), 0), 753 QualType(MemPtrArg->getClass(), 0), 754 Info, Deduced, 0); 755 } 756 757 // (clang extension) 758 // 759 // type(^)(T) 760 // T(^)() 761 // T(^)(T) 762 case Type::BlockPointer: { 763 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param); 764 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg); 765 766 if (!BlockPtrArg) 767 return Sema::TDK_NonDeducedMismatch; 768 769 return DeduceTemplateArguments(S, TemplateParams, 770 BlockPtrParam->getPointeeType(), 771 BlockPtrArg->getPointeeType(), Info, 772 Deduced, 0); 773 } 774 775 case Type::TypeOfExpr: 776 case Type::TypeOf: 777 case Type::DependentName: 778 // No template argument deduction for these types 779 return Sema::TDK_Success; 780 781 default: 782 break; 783 } 784 785 // FIXME: Many more cases to go (to go). 786 return Sema::TDK_Success; 787} 788 789static Sema::TemplateDeductionResult 790DeduceTemplateArguments(Sema &S, 791 TemplateParameterList *TemplateParams, 792 const TemplateArgument &Param, 793 const TemplateArgument &Arg, 794 Sema::TemplateDeductionInfo &Info, 795 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 796 switch (Param.getKind()) { 797 case TemplateArgument::Null: 798 assert(false && "Null template argument in parameter list"); 799 break; 800 801 case TemplateArgument::Type: 802 if (Arg.getKind() == TemplateArgument::Type) 803 return DeduceTemplateArguments(S, TemplateParams, Param.getAsType(), 804 Arg.getAsType(), Info, Deduced, 0); 805 Info.FirstArg = Param; 806 Info.SecondArg = Arg; 807 return Sema::TDK_NonDeducedMismatch; 808 809 case TemplateArgument::Template: 810 if (Arg.getKind() == TemplateArgument::Template) 811 return DeduceTemplateArguments(S, TemplateParams, 812 Param.getAsTemplate(), 813 Arg.getAsTemplate(), Info, Deduced); 814 Info.FirstArg = Param; 815 Info.SecondArg = Arg; 816 return Sema::TDK_NonDeducedMismatch; 817 818 case TemplateArgument::Declaration: 819 if (Arg.getKind() == TemplateArgument::Declaration && 820 Param.getAsDecl()->getCanonicalDecl() == 821 Arg.getAsDecl()->getCanonicalDecl()) 822 return Sema::TDK_Success; 823 824 Info.FirstArg = Param; 825 Info.SecondArg = Arg; 826 return Sema::TDK_NonDeducedMismatch; 827 828 case TemplateArgument::Integral: 829 if (Arg.getKind() == TemplateArgument::Integral) { 830 if (hasSameExtendedValue(*Param.getAsIntegral(), *Arg.getAsIntegral())) 831 return Sema::TDK_Success; 832 833 Info.FirstArg = Param; 834 Info.SecondArg = Arg; 835 return Sema::TDK_NonDeducedMismatch; 836 } 837 838 if (Arg.getKind() == TemplateArgument::Expression) { 839 Info.FirstArg = Param; 840 Info.SecondArg = Arg; 841 return Sema::TDK_NonDeducedMismatch; 842 } 843 844 assert(false && "Type/value mismatch"); 845 Info.FirstArg = Param; 846 Info.SecondArg = Arg; 847 return Sema::TDK_NonDeducedMismatch; 848 849 case TemplateArgument::Expression: { 850 if (NonTypeTemplateParmDecl *NTTP 851 = getDeducedParameterFromExpr(Param.getAsExpr())) { 852 if (Arg.getKind() == TemplateArgument::Integral) 853 return DeduceNonTypeTemplateArgument(S, NTTP, 854 *Arg.getAsIntegral(), 855 Arg.getIntegralType(), 856 /*ArrayBound=*/false, 857 Info, Deduced); 858 if (Arg.getKind() == TemplateArgument::Expression) 859 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsExpr(), 860 Info, Deduced); 861 if (Arg.getKind() == TemplateArgument::Declaration) 862 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsDecl(), 863 Info, Deduced); 864 865 assert(false && "Type/value mismatch"); 866 Info.FirstArg = Param; 867 Info.SecondArg = Arg; 868 return Sema::TDK_NonDeducedMismatch; 869 } 870 871 // Can't deduce anything, but that's okay. 872 return Sema::TDK_Success; 873 } 874 case TemplateArgument::Pack: 875 assert(0 && "FIXME: Implement!"); 876 break; 877 } 878 879 return Sema::TDK_Success; 880} 881 882static Sema::TemplateDeductionResult 883DeduceTemplateArguments(Sema &S, 884 TemplateParameterList *TemplateParams, 885 const TemplateArgumentList &ParamList, 886 const TemplateArgumentList &ArgList, 887 Sema::TemplateDeductionInfo &Info, 888 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced) { 889 assert(ParamList.size() == ArgList.size()); 890 for (unsigned I = 0, N = ParamList.size(); I != N; ++I) { 891 if (Sema::TemplateDeductionResult Result 892 = DeduceTemplateArguments(S, TemplateParams, 893 ParamList[I], ArgList[I], 894 Info, Deduced)) 895 return Result; 896 } 897 return Sema::TDK_Success; 898} 899 900/// \brief Determine whether two template arguments are the same. 901static bool isSameTemplateArg(ASTContext &Context, 902 const TemplateArgument &X, 903 const TemplateArgument &Y) { 904 if (X.getKind() != Y.getKind()) 905 return false; 906 907 switch (X.getKind()) { 908 case TemplateArgument::Null: 909 assert(false && "Comparing NULL template argument"); 910 break; 911 912 case TemplateArgument::Type: 913 return Context.getCanonicalType(X.getAsType()) == 914 Context.getCanonicalType(Y.getAsType()); 915 916 case TemplateArgument::Declaration: 917 return X.getAsDecl()->getCanonicalDecl() == 918 Y.getAsDecl()->getCanonicalDecl(); 919 920 case TemplateArgument::Template: 921 return Context.getCanonicalTemplateName(X.getAsTemplate()) 922 .getAsVoidPointer() == 923 Context.getCanonicalTemplateName(Y.getAsTemplate()) 924 .getAsVoidPointer(); 925 926 case TemplateArgument::Integral: 927 return *X.getAsIntegral() == *Y.getAsIntegral(); 928 929 case TemplateArgument::Expression: { 930 llvm::FoldingSetNodeID XID, YID; 931 X.getAsExpr()->Profile(XID, Context, true); 932 Y.getAsExpr()->Profile(YID, Context, true); 933 return XID == YID; 934 } 935 936 case TemplateArgument::Pack: 937 if (X.pack_size() != Y.pack_size()) 938 return false; 939 940 for (TemplateArgument::pack_iterator XP = X.pack_begin(), 941 XPEnd = X.pack_end(), 942 YP = Y.pack_begin(); 943 XP != XPEnd; ++XP, ++YP) 944 if (!isSameTemplateArg(Context, *XP, *YP)) 945 return false; 946 947 return true; 948 } 949 950 return false; 951} 952 953/// \brief Helper function to build a TemplateParameter when we don't 954/// know its type statically. 955static TemplateParameter makeTemplateParameter(Decl *D) { 956 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D)) 957 return TemplateParameter(TTP); 958 else if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) 959 return TemplateParameter(NTTP); 960 961 return TemplateParameter(cast<TemplateTemplateParmDecl>(D)); 962} 963 964/// Complete template argument deduction for a class template partial 965/// specialization. 966static Sema::TemplateDeductionResult 967FinishTemplateArgumentDeduction(Sema &S, 968 ClassTemplatePartialSpecializationDecl *Partial, 969 const TemplateArgumentList &TemplateArgs, 970 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 971 Sema::TemplateDeductionInfo &Info) { 972 // Trap errors. 973 Sema::SFINAETrap Trap(S); 974 975 Sema::ContextRAII SavedContext(S, Partial); 976 977 // C++ [temp.deduct.type]p2: 978 // [...] or if any template argument remains neither deduced nor 979 // explicitly specified, template argument deduction fails. 980 TemplateArgumentListBuilder Builder(Partial->getTemplateParameters(), 981 Deduced.size()); 982 for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { 983 if (Deduced[I].isNull()) { 984 Decl *Param 985 = const_cast<NamedDecl *>( 986 Partial->getTemplateParameters()->getParam(I)); 987 Info.Param = makeTemplateParameter(Param); 988 return Sema::TDK_Incomplete; 989 } 990 991 Builder.Append(Deduced[I]); 992 } 993 994 // Form the template argument list from the deduced template arguments. 995 TemplateArgumentList *DeducedArgumentList 996 = new (S.Context) TemplateArgumentList(S.Context, Builder, 997 /*TakeArgs=*/true); 998 Info.reset(DeducedArgumentList); 999 1000 // Substitute the deduced template arguments into the template 1001 // arguments of the class template partial specialization, and 1002 // verify that the instantiated template arguments are both valid 1003 // and are equivalent to the template arguments originally provided 1004 // to the class template. 1005 // FIXME: Do we have to correct the types of deduced non-type template 1006 // arguments (in particular, integral non-type template arguments?). 1007 Sema::LocalInstantiationScope InstScope(S); 1008 ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); 1009 const TemplateArgumentLoc *PartialTemplateArgs 1010 = Partial->getTemplateArgsAsWritten(); 1011 unsigned N = Partial->getNumTemplateArgsAsWritten(); 1012 1013 // Note that we don't provide the langle and rangle locations. 1014 TemplateArgumentListInfo InstArgs; 1015 1016 for (unsigned I = 0; I != N; ++I) { 1017 Decl *Param = const_cast<NamedDecl *>( 1018 ClassTemplate->getTemplateParameters()->getParam(I)); 1019 TemplateArgumentLoc InstArg; 1020 if (S.Subst(PartialTemplateArgs[I], InstArg, 1021 MultiLevelTemplateArgumentList(*DeducedArgumentList))) { 1022 Info.Param = makeTemplateParameter(Param); 1023 Info.FirstArg = PartialTemplateArgs[I].getArgument(); 1024 return Sema::TDK_SubstitutionFailure; 1025 } 1026 InstArgs.addArgument(InstArg); 1027 } 1028 1029 TemplateArgumentListBuilder ConvertedInstArgs( 1030 ClassTemplate->getTemplateParameters(), N); 1031 1032 if (S.CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(), 1033 InstArgs, false, ConvertedInstArgs)) { 1034 // FIXME: fail with more useful information? 1035 return Sema::TDK_SubstitutionFailure; 1036 } 1037 1038 for (unsigned I = 0, E = ConvertedInstArgs.flatSize(); I != E; ++I) { 1039 TemplateArgument InstArg = ConvertedInstArgs.getFlatArguments()[I]; 1040 1041 Decl *Param = const_cast<NamedDecl *>( 1042 ClassTemplate->getTemplateParameters()->getParam(I)); 1043 1044 if (InstArg.getKind() == TemplateArgument::Expression) { 1045 // When the argument is an expression, check the expression result 1046 // against the actual template parameter to get down to the canonical 1047 // template argument. 1048 Expr *InstExpr = InstArg.getAsExpr(); 1049 if (NonTypeTemplateParmDecl *NTTP 1050 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 1051 if (S.CheckTemplateArgument(NTTP, NTTP->getType(), InstExpr, InstArg)) { 1052 Info.Param = makeTemplateParameter(Param); 1053 Info.FirstArg = Partial->getTemplateArgs()[I]; 1054 return Sema::TDK_SubstitutionFailure; 1055 } 1056 } 1057 } 1058 1059 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) { 1060 Info.Param = makeTemplateParameter(Param); 1061 Info.FirstArg = TemplateArgs[I]; 1062 Info.SecondArg = InstArg; 1063 return Sema::TDK_NonDeducedMismatch; 1064 } 1065 } 1066 1067 if (Trap.hasErrorOccurred()) 1068 return Sema::TDK_SubstitutionFailure; 1069 1070 return Sema::TDK_Success; 1071} 1072 1073/// \brief Perform template argument deduction to determine whether 1074/// the given template arguments match the given class template 1075/// partial specialization per C++ [temp.class.spec.match]. 1076Sema::TemplateDeductionResult 1077Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, 1078 const TemplateArgumentList &TemplateArgs, 1079 TemplateDeductionInfo &Info) { 1080 // C++ [temp.class.spec.match]p2: 1081 // A partial specialization matches a given actual template 1082 // argument list if the template arguments of the partial 1083 // specialization can be deduced from the actual template argument 1084 // list (14.8.2). 1085 SFINAETrap Trap(*this); 1086 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1087 Deduced.resize(Partial->getTemplateParameters()->size()); 1088 if (TemplateDeductionResult Result 1089 = ::DeduceTemplateArguments(*this, 1090 Partial->getTemplateParameters(), 1091 Partial->getTemplateArgs(), 1092 TemplateArgs, Info, Deduced)) 1093 return Result; 1094 1095 InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, 1096 Deduced.data(), Deduced.size()); 1097 if (Inst) 1098 return TDK_InstantiationDepth; 1099 1100 if (Trap.hasErrorOccurred()) 1101 return Sema::TDK_SubstitutionFailure; 1102 1103 return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs, 1104 Deduced, Info); 1105} 1106 1107/// \brief Determine whether the given type T is a simple-template-id type. 1108static bool isSimpleTemplateIdType(QualType T) { 1109 if (const TemplateSpecializationType *Spec 1110 = T->getAs<TemplateSpecializationType>()) 1111 return Spec->getTemplateName().getAsTemplateDecl() != 0; 1112 1113 return false; 1114} 1115 1116/// \brief Substitute the explicitly-provided template arguments into the 1117/// given function template according to C++ [temp.arg.explicit]. 1118/// 1119/// \param FunctionTemplate the function template into which the explicit 1120/// template arguments will be substituted. 1121/// 1122/// \param ExplicitTemplateArguments the explicitly-specified template 1123/// arguments. 1124/// 1125/// \param Deduced the deduced template arguments, which will be populated 1126/// with the converted and checked explicit template arguments. 1127/// 1128/// \param ParamTypes will be populated with the instantiated function 1129/// parameters. 1130/// 1131/// \param FunctionType if non-NULL, the result type of the function template 1132/// will also be instantiated and the pointed-to value will be updated with 1133/// the instantiated function type. 1134/// 1135/// \param Info if substitution fails for any reason, this object will be 1136/// populated with more information about the failure. 1137/// 1138/// \returns TDK_Success if substitution was successful, or some failure 1139/// condition. 1140Sema::TemplateDeductionResult 1141Sema::SubstituteExplicitTemplateArguments( 1142 FunctionTemplateDecl *FunctionTemplate, 1143 const TemplateArgumentListInfo &ExplicitTemplateArgs, 1144 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1145 llvm::SmallVectorImpl<QualType> &ParamTypes, 1146 QualType *FunctionType, 1147 TemplateDeductionInfo &Info) { 1148 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1149 TemplateParameterList *TemplateParams 1150 = FunctionTemplate->getTemplateParameters(); 1151 1152 if (ExplicitTemplateArgs.size() == 0) { 1153 // No arguments to substitute; just copy over the parameter types and 1154 // fill in the function type. 1155 for (FunctionDecl::param_iterator P = Function->param_begin(), 1156 PEnd = Function->param_end(); 1157 P != PEnd; 1158 ++P) 1159 ParamTypes.push_back((*P)->getType()); 1160 1161 if (FunctionType) 1162 *FunctionType = Function->getType(); 1163 return TDK_Success; 1164 } 1165 1166 // Substitution of the explicit template arguments into a function template 1167 /// is a SFINAE context. Trap any errors that might occur. 1168 SFINAETrap Trap(*this); 1169 1170 // C++ [temp.arg.explicit]p3: 1171 // Template arguments that are present shall be specified in the 1172 // declaration order of their corresponding template-parameters. The 1173 // template argument list shall not specify more template-arguments than 1174 // there are corresponding template-parameters. 1175 TemplateArgumentListBuilder Builder(TemplateParams, 1176 ExplicitTemplateArgs.size()); 1177 1178 // Enter a new template instantiation context where we check the 1179 // explicitly-specified template arguments against this function template, 1180 // and then substitute them into the function parameter types. 1181 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 1182 FunctionTemplate, Deduced.data(), Deduced.size(), 1183 ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution); 1184 if (Inst) 1185 return TDK_InstantiationDepth; 1186 1187 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 1188 1189 if (CheckTemplateArgumentList(FunctionTemplate, 1190 SourceLocation(), 1191 ExplicitTemplateArgs, 1192 true, 1193 Builder) || Trap.hasErrorOccurred()) 1194 return TDK_InvalidExplicitArguments; 1195 1196 // Form the template argument list from the explicitly-specified 1197 // template arguments. 1198 TemplateArgumentList *ExplicitArgumentList 1199 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1200 Info.reset(ExplicitArgumentList); 1201 1202 // Instantiate the types of each of the function parameters given the 1203 // explicitly-specified template arguments. 1204 for (FunctionDecl::param_iterator P = Function->param_begin(), 1205 PEnd = Function->param_end(); 1206 P != PEnd; 1207 ++P) { 1208 QualType ParamType 1209 = SubstType((*P)->getType(), 1210 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 1211 (*P)->getLocation(), (*P)->getDeclName()); 1212 if (ParamType.isNull() || Trap.hasErrorOccurred()) 1213 return TDK_SubstitutionFailure; 1214 1215 ParamTypes.push_back(ParamType); 1216 } 1217 1218 // If the caller wants a full function type back, instantiate the return 1219 // type and form that function type. 1220 if (FunctionType) { 1221 // FIXME: exception-specifications? 1222 const FunctionProtoType *Proto 1223 = Function->getType()->getAs<FunctionProtoType>(); 1224 assert(Proto && "Function template does not have a prototype?"); 1225 1226 QualType ResultType 1227 = SubstType(Proto->getResultType(), 1228 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 1229 Function->getTypeSpecStartLoc(), 1230 Function->getDeclName()); 1231 if (ResultType.isNull() || Trap.hasErrorOccurred()) 1232 return TDK_SubstitutionFailure; 1233 1234 *FunctionType = BuildFunctionType(ResultType, 1235 ParamTypes.data(), ParamTypes.size(), 1236 Proto->isVariadic(), 1237 Proto->getTypeQuals(), 1238 Function->getLocation(), 1239 Function->getDeclName()); 1240 if (FunctionType->isNull() || Trap.hasErrorOccurred()) 1241 return TDK_SubstitutionFailure; 1242 } 1243 1244 // C++ [temp.arg.explicit]p2: 1245 // Trailing template arguments that can be deduced (14.8.2) may be 1246 // omitted from the list of explicit template-arguments. If all of the 1247 // template arguments can be deduced, they may all be omitted; in this 1248 // case, the empty template argument list <> itself may also be omitted. 1249 // 1250 // Take all of the explicitly-specified arguments and put them into the 1251 // set of deduced template arguments. 1252 Deduced.reserve(TemplateParams->size()); 1253 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) 1254 Deduced.push_back(ExplicitArgumentList->get(I)); 1255 1256 return TDK_Success; 1257} 1258 1259/// \brief Allocate a TemplateArgumentLoc where all locations have 1260/// been initialized to the given location. 1261/// 1262/// \param S The semantic analysis object. 1263/// 1264/// \param The template argument we are producing template argument 1265/// location information for. 1266/// 1267/// \param NTTPType For a declaration template argument, the type of 1268/// the non-type template parameter that corresponds to this template 1269/// argument. 1270/// 1271/// \param Loc The source location to use for the resulting template 1272/// argument. 1273static TemplateArgumentLoc 1274getTrivialTemplateArgumentLoc(Sema &S, 1275 const TemplateArgument &Arg, 1276 QualType NTTPType, 1277 SourceLocation Loc) { 1278 switch (Arg.getKind()) { 1279 case TemplateArgument::Null: 1280 llvm_unreachable("Can't get a NULL template argument here"); 1281 break; 1282 1283 case TemplateArgument::Type: 1284 return TemplateArgumentLoc(Arg, 1285 S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); 1286 1287 case TemplateArgument::Declaration: { 1288 Expr *E 1289 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 1290 .takeAs<Expr>(); 1291 return TemplateArgumentLoc(TemplateArgument(E), E); 1292 } 1293 1294 case TemplateArgument::Integral: { 1295 Expr *E 1296 = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>(); 1297 return TemplateArgumentLoc(TemplateArgument(E), E); 1298 } 1299 1300 case TemplateArgument::Template: 1301 return TemplateArgumentLoc(Arg, SourceRange(), Loc); 1302 1303 case TemplateArgument::Expression: 1304 return TemplateArgumentLoc(Arg, Arg.getAsExpr()); 1305 1306 case TemplateArgument::Pack: 1307 llvm_unreachable("Template parameter packs are not yet supported"); 1308 } 1309 1310 return TemplateArgumentLoc(); 1311} 1312 1313/// \brief Finish template argument deduction for a function template, 1314/// checking the deduced template arguments for completeness and forming 1315/// the function template specialization. 1316Sema::TemplateDeductionResult 1317Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate, 1318 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1319 unsigned NumExplicitlySpecified, 1320 FunctionDecl *&Specialization, 1321 TemplateDeductionInfo &Info) { 1322 TemplateParameterList *TemplateParams 1323 = FunctionTemplate->getTemplateParameters(); 1324 1325 // Template argument deduction for function templates in a SFINAE context. 1326 // Trap any errors that might occur. 1327 SFINAETrap Trap(*this); 1328 1329 // Enter a new template instantiation context while we instantiate the 1330 // actual function declaration. 1331 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 1332 FunctionTemplate, Deduced.data(), Deduced.size(), 1333 ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution); 1334 if (Inst) 1335 return TDK_InstantiationDepth; 1336 1337 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl()); 1338 1339 // C++ [temp.deduct.type]p2: 1340 // [...] or if any template argument remains neither deduced nor 1341 // explicitly specified, template argument deduction fails. 1342 TemplateArgumentListBuilder Builder(TemplateParams, Deduced.size()); 1343 for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { 1344 NamedDecl *Param = FunctionTemplate->getTemplateParameters()->getParam(I); 1345 if (!Deduced[I].isNull()) { 1346 if (I < NumExplicitlySpecified || 1347 Deduced[I].getKind() == TemplateArgument::Type) { 1348 // We have already fully type-checked and converted this 1349 // argument (because it was explicitly-specified) or no 1350 // additional checking is necessary (because it's a template 1351 // type parameter). Just record the presence of this 1352 // parameter. 1353 Builder.Append(Deduced[I]); 1354 continue; 1355 } 1356 1357 // We have deduced this argument, so it still needs to be 1358 // checked and converted. 1359 1360 // First, for a non-type template parameter type that is 1361 // initialized by a declaration, we need the type of the 1362 // corresponding non-type template parameter. 1363 QualType NTTPType; 1364 if (NonTypeTemplateParmDecl *NTTP 1365 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 1366 if (Deduced[I].getKind() == TemplateArgument::Declaration) { 1367 NTTPType = NTTP->getType(); 1368 if (NTTPType->isDependentType()) { 1369 TemplateArgumentList TemplateArgs(Context, Builder, 1370 /*TakeArgs=*/false); 1371 NTTPType = SubstType(NTTPType, 1372 MultiLevelTemplateArgumentList(TemplateArgs), 1373 NTTP->getLocation(), 1374 NTTP->getDeclName()); 1375 if (NTTPType.isNull()) { 1376 Info.Param = makeTemplateParameter(Param); 1377 return TDK_SubstitutionFailure; 1378 } 1379 } 1380 } 1381 } 1382 1383 // Convert the deduced template argument into a template 1384 // argument that we can check, almost as if the user had written 1385 // the template argument explicitly. 1386 TemplateArgumentLoc Arg = getTrivialTemplateArgumentLoc(*this, 1387 Deduced[I], 1388 NTTPType, 1389 SourceLocation()); 1390 1391 // Check the template argument, converting it as necessary. 1392 if (CheckTemplateArgument(Param, Arg, 1393 FunctionTemplate, 1394 FunctionTemplate->getLocation(), 1395 FunctionTemplate->getSourceRange().getEnd(), 1396 Builder, 1397 Deduced[I].wasDeducedFromArrayBound() 1398 ? CTAK_DeducedFromArrayBound 1399 : CTAK_Deduced)) { 1400 Info.Param = makeTemplateParameter( 1401 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1402 return TDK_SubstitutionFailure; 1403 } 1404 1405 continue; 1406 } 1407 1408 // Substitute into the default template argument, if available. 1409 TemplateArgumentLoc DefArg 1410 = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate, 1411 FunctionTemplate->getLocation(), 1412 FunctionTemplate->getSourceRange().getEnd(), 1413 Param, 1414 Builder); 1415 1416 // If there was no default argument, deduction is incomplete. 1417 if (DefArg.getArgument().isNull()) { 1418 Info.Param = makeTemplateParameter( 1419 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1420 return TDK_Incomplete; 1421 } 1422 1423 // Check whether we can actually use the default argument. 1424 if (CheckTemplateArgument(Param, DefArg, 1425 FunctionTemplate, 1426 FunctionTemplate->getLocation(), 1427 FunctionTemplate->getSourceRange().getEnd(), 1428 Builder, 1429 CTAK_Deduced)) { 1430 Info.Param = makeTemplateParameter( 1431 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1432 return TDK_SubstitutionFailure; 1433 } 1434 1435 // If we get here, we successfully used the default template argument. 1436 } 1437 1438 // Form the template argument list from the deduced template arguments. 1439 TemplateArgumentList *DeducedArgumentList 1440 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1441 Info.reset(DeducedArgumentList); 1442 1443 // Substitute the deduced template arguments into the function template 1444 // declaration to produce the function template specialization. 1445 DeclContext *Owner = FunctionTemplate->getDeclContext(); 1446 if (FunctionTemplate->getFriendObjectKind()) 1447 Owner = FunctionTemplate->getLexicalDeclContext(); 1448 Specialization = cast_or_null<FunctionDecl>( 1449 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, 1450 MultiLevelTemplateArgumentList(*DeducedArgumentList))); 1451 if (!Specialization) 1452 return TDK_SubstitutionFailure; 1453 1454 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() == 1455 FunctionTemplate->getCanonicalDecl()); 1456 1457 // If the template argument list is owned by the function template 1458 // specialization, release it. 1459 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList) 1460 Info.take(); 1461 1462 // There may have been an error that did not prevent us from constructing a 1463 // declaration. Mark the declaration invalid and return with a substitution 1464 // failure. 1465 if (Trap.hasErrorOccurred()) { 1466 Specialization->setInvalidDecl(true); 1467 return TDK_SubstitutionFailure; 1468 } 1469 1470 return TDK_Success; 1471} 1472 1473static QualType GetTypeOfFunction(ASTContext &Context, 1474 bool isAddressOfOperand, 1475 FunctionDecl *Fn) { 1476 if (!isAddressOfOperand) return Fn->getType(); 1477 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) 1478 if (Method->isInstance()) 1479 return Context.getMemberPointerType(Fn->getType(), 1480 Context.getTypeDeclType(Method->getParent()).getTypePtr()); 1481 return Context.getPointerType(Fn->getType()); 1482} 1483 1484/// Apply the deduction rules for overload sets. 1485/// 1486/// \return the null type if this argument should be treated as an 1487/// undeduced context 1488static QualType 1489ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, 1490 Expr *Arg, QualType ParamType) { 1491 llvm::PointerIntPair<OverloadExpr*,1> R = OverloadExpr::find(Arg); 1492 1493 bool isAddressOfOperand = bool(R.getInt()); 1494 OverloadExpr *Ovl = R.getPointer(); 1495 1496 // If there were explicit template arguments, we can only find 1497 // something via C++ [temp.arg.explicit]p3, i.e. if the arguments 1498 // unambiguously name a full specialization. 1499 if (Ovl->hasExplicitTemplateArgs()) { 1500 // But we can still look for an explicit specialization. 1501 if (FunctionDecl *ExplicitSpec 1502 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 1503 return GetTypeOfFunction(S.Context, isAddressOfOperand, ExplicitSpec); 1504 return QualType(); 1505 } 1506 1507 // C++0x [temp.deduct.call]p6: 1508 // When P is a function type, pointer to function type, or pointer 1509 // to member function type: 1510 1511 if (!ParamType->isFunctionType() && 1512 !ParamType->isFunctionPointerType() && 1513 !ParamType->isMemberFunctionPointerType()) 1514 return QualType(); 1515 1516 QualType Match; 1517 for (UnresolvedSetIterator I = Ovl->decls_begin(), 1518 E = Ovl->decls_end(); I != E; ++I) { 1519 NamedDecl *D = (*I)->getUnderlyingDecl(); 1520 1521 // - If the argument is an overload set containing one or more 1522 // function templates, the parameter is treated as a 1523 // non-deduced context. 1524 if (isa<FunctionTemplateDecl>(D)) 1525 return QualType(); 1526 1527 FunctionDecl *Fn = cast<FunctionDecl>(D); 1528 QualType ArgType = GetTypeOfFunction(S.Context, isAddressOfOperand, Fn); 1529 1530 // - If the argument is an overload set (not containing function 1531 // templates), trial argument deduction is attempted using each 1532 // of the members of the set. If deduction succeeds for only one 1533 // of the overload set members, that member is used as the 1534 // argument value for the deduction. If deduction succeeds for 1535 // more than one member of the overload set the parameter is 1536 // treated as a non-deduced context. 1537 1538 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 1539 // Type deduction is done independently for each P/A pair, and 1540 // the deduced template argument values are then combined. 1541 // So we do not reject deductions which were made elsewhere. 1542 llvm::SmallVector<DeducedTemplateArgument, 8> 1543 Deduced(TemplateParams->size()); 1544 Sema::TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 1545 unsigned TDF = 0; 1546 1547 Sema::TemplateDeductionResult Result 1548 = DeduceTemplateArguments(S, TemplateParams, 1549 ParamType, ArgType, 1550 Info, Deduced, TDF); 1551 if (Result) continue; 1552 if (!Match.isNull()) return QualType(); 1553 Match = ArgType; 1554 } 1555 1556 return Match; 1557} 1558 1559/// \brief Perform template argument deduction from a function call 1560/// (C++ [temp.deduct.call]). 1561/// 1562/// \param FunctionTemplate the function template for which we are performing 1563/// template argument deduction. 1564/// 1565/// \param ExplicitTemplateArguments the explicit template arguments provided 1566/// for this call. 1567/// 1568/// \param Args the function call arguments 1569/// 1570/// \param NumArgs the number of arguments in Args 1571/// 1572/// \param Name the name of the function being called. This is only significant 1573/// when the function template is a conversion function template, in which 1574/// case this routine will also perform template argument deduction based on 1575/// the function to which 1576/// 1577/// \param Specialization if template argument deduction was successful, 1578/// this will be set to the function template specialization produced by 1579/// template argument deduction. 1580/// 1581/// \param Info the argument will be updated to provide additional information 1582/// about template argument deduction. 1583/// 1584/// \returns the result of template argument deduction. 1585Sema::TemplateDeductionResult 1586Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1587 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1588 Expr **Args, unsigned NumArgs, 1589 FunctionDecl *&Specialization, 1590 TemplateDeductionInfo &Info) { 1591 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1592 1593 // C++ [temp.deduct.call]p1: 1594 // Template argument deduction is done by comparing each function template 1595 // parameter type (call it P) with the type of the corresponding argument 1596 // of the call (call it A) as described below. 1597 unsigned CheckArgs = NumArgs; 1598 if (NumArgs < Function->getMinRequiredArguments()) 1599 return TDK_TooFewArguments; 1600 else if (NumArgs > Function->getNumParams()) { 1601 const FunctionProtoType *Proto 1602 = Function->getType()->getAs<FunctionProtoType>(); 1603 if (!Proto->isVariadic()) 1604 return TDK_TooManyArguments; 1605 1606 CheckArgs = Function->getNumParams(); 1607 } 1608 1609 // The types of the parameters from which we will perform template argument 1610 // deduction. 1611 Sema::LocalInstantiationScope InstScope(*this); 1612 TemplateParameterList *TemplateParams 1613 = FunctionTemplate->getTemplateParameters(); 1614 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1615 llvm::SmallVector<QualType, 4> ParamTypes; 1616 unsigned NumExplicitlySpecified = 0; 1617 if (ExplicitTemplateArgs) { 1618 TemplateDeductionResult Result = 1619 SubstituteExplicitTemplateArguments(FunctionTemplate, 1620 *ExplicitTemplateArgs, 1621 Deduced, 1622 ParamTypes, 1623 0, 1624 Info); 1625 if (Result) 1626 return Result; 1627 1628 NumExplicitlySpecified = Deduced.size(); 1629 } else { 1630 // Just fill in the parameter types from the function declaration. 1631 for (unsigned I = 0; I != CheckArgs; ++I) 1632 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 1633 } 1634 1635 // Deduce template arguments from the function parameters. 1636 Deduced.resize(TemplateParams->size()); 1637 for (unsigned I = 0; I != CheckArgs; ++I) { 1638 QualType ParamType = ParamTypes[I]; 1639 QualType ArgType = Args[I]->getType(); 1640 1641 // Overload sets usually make this parameter an undeduced 1642 // context, but there are sometimes special circumstances. 1643 if (ArgType == Context.OverloadTy) { 1644 ArgType = ResolveOverloadForDeduction(*this, TemplateParams, 1645 Args[I], ParamType); 1646 if (ArgType.isNull()) 1647 continue; 1648 } 1649 1650 // C++ [temp.deduct.call]p2: 1651 // If P is not a reference type: 1652 QualType CanonParamType = Context.getCanonicalType(ParamType); 1653 bool ParamWasReference = isa<ReferenceType>(CanonParamType); 1654 if (!ParamWasReference) { 1655 // - If A is an array type, the pointer type produced by the 1656 // array-to-pointer standard conversion (4.2) is used in place of 1657 // A for type deduction; otherwise, 1658 if (ArgType->isArrayType()) 1659 ArgType = Context.getArrayDecayedType(ArgType); 1660 // - If A is a function type, the pointer type produced by the 1661 // function-to-pointer standard conversion (4.3) is used in place 1662 // of A for type deduction; otherwise, 1663 else if (ArgType->isFunctionType()) 1664 ArgType = Context.getPointerType(ArgType); 1665 else { 1666 // - If A is a cv-qualified type, the top level cv-qualifiers of A’s 1667 // type are ignored for type deduction. 1668 QualType CanonArgType = Context.getCanonicalType(ArgType); 1669 if (CanonArgType.getLocalCVRQualifiers()) 1670 ArgType = CanonArgType.getLocalUnqualifiedType(); 1671 } 1672 } 1673 1674 // C++0x [temp.deduct.call]p3: 1675 // If P is a cv-qualified type, the top level cv-qualifiers of P’s type 1676 // are ignored for type deduction. 1677 if (CanonParamType.getLocalCVRQualifiers()) 1678 ParamType = CanonParamType.getLocalUnqualifiedType(); 1679 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) { 1680 // [...] If P is a reference type, the type referred to by P is used 1681 // for type deduction. 1682 ParamType = ParamRefType->getPointeeType(); 1683 1684 // [...] If P is of the form T&&, where T is a template parameter, and 1685 // the argument is an lvalue, the type A& is used in place of A for 1686 // type deduction. 1687 if (isa<RValueReferenceType>(ParamRefType) && 1688 ParamRefType->getAs<TemplateTypeParmType>() && 1689 Args[I]->isLvalue(Context) == Expr::LV_Valid) 1690 ArgType = Context.getLValueReferenceType(ArgType); 1691 } 1692 1693 // C++0x [temp.deduct.call]p4: 1694 // In general, the deduction process attempts to find template argument 1695 // values that will make the deduced A identical to A (after the type A 1696 // is transformed as described above). [...] 1697 unsigned TDF = TDF_SkipNonDependent; 1698 1699 // - If the original P is a reference type, the deduced A (i.e., the 1700 // type referred to by the reference) can be more cv-qualified than 1701 // the transformed A. 1702 if (ParamWasReference) 1703 TDF |= TDF_ParamWithReferenceType; 1704 // - The transformed A can be another pointer or pointer to member 1705 // type that can be converted to the deduced A via a qualification 1706 // conversion (4.4). 1707 if (ArgType->isPointerType() || ArgType->isMemberPointerType()) 1708 TDF |= TDF_IgnoreQualifiers; 1709 // - If P is a class and P has the form simple-template-id, then the 1710 // transformed A can be a derived class of the deduced A. Likewise, 1711 // if P is a pointer to a class of the form simple-template-id, the 1712 // transformed A can be a pointer to a derived class pointed to by 1713 // the deduced A. 1714 if (isSimpleTemplateIdType(ParamType) || 1715 (isa<PointerType>(ParamType) && 1716 isSimpleTemplateIdType( 1717 ParamType->getAs<PointerType>()->getPointeeType()))) 1718 TDF |= TDF_DerivedClass; 1719 1720 if (TemplateDeductionResult Result 1721 = ::DeduceTemplateArguments(*this, TemplateParams, 1722 ParamType, ArgType, Info, Deduced, 1723 TDF)) 1724 return Result; 1725 1726 // FIXME: we need to check that the deduced A is the same as A, 1727 // modulo the various allowed differences. 1728 } 1729 1730 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 1731 NumExplicitlySpecified, 1732 Specialization, Info); 1733} 1734 1735/// \brief Deduce template arguments when taking the address of a function 1736/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 1737/// a template. 1738/// 1739/// \param FunctionTemplate the function template for which we are performing 1740/// template argument deduction. 1741/// 1742/// \param ExplicitTemplateArguments the explicitly-specified template 1743/// arguments. 1744/// 1745/// \param ArgFunctionType the function type that will be used as the 1746/// "argument" type (A) when performing template argument deduction from the 1747/// function template's function type. This type may be NULL, if there is no 1748/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 1749/// 1750/// \param Specialization if template argument deduction was successful, 1751/// this will be set to the function template specialization produced by 1752/// template argument deduction. 1753/// 1754/// \param Info the argument will be updated to provide additional information 1755/// about template argument deduction. 1756/// 1757/// \returns the result of template argument deduction. 1758Sema::TemplateDeductionResult 1759Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1760 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1761 QualType ArgFunctionType, 1762 FunctionDecl *&Specialization, 1763 TemplateDeductionInfo &Info) { 1764 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1765 TemplateParameterList *TemplateParams 1766 = FunctionTemplate->getTemplateParameters(); 1767 QualType FunctionType = Function->getType(); 1768 1769 // Substitute any explicit template arguments. 1770 Sema::LocalInstantiationScope InstScope(*this); 1771 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1772 unsigned NumExplicitlySpecified = 0; 1773 llvm::SmallVector<QualType, 4> ParamTypes; 1774 if (ExplicitTemplateArgs) { 1775 if (TemplateDeductionResult Result 1776 = SubstituteExplicitTemplateArguments(FunctionTemplate, 1777 *ExplicitTemplateArgs, 1778 Deduced, ParamTypes, 1779 &FunctionType, Info)) 1780 return Result; 1781 1782 NumExplicitlySpecified = Deduced.size(); 1783 } 1784 1785 // Template argument deduction for function templates in a SFINAE context. 1786 // Trap any errors that might occur. 1787 SFINAETrap Trap(*this); 1788 1789 Deduced.resize(TemplateParams->size()); 1790 1791 if (!ArgFunctionType.isNull()) { 1792 // Deduce template arguments from the function type. 1793 if (TemplateDeductionResult Result 1794 = ::DeduceTemplateArguments(*this, TemplateParams, 1795 FunctionType, ArgFunctionType, Info, 1796 Deduced, 0)) 1797 return Result; 1798 } 1799 1800 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 1801 NumExplicitlySpecified, 1802 Specialization, Info); 1803} 1804 1805/// \brief Deduce template arguments for a templated conversion 1806/// function (C++ [temp.deduct.conv]) and, if successful, produce a 1807/// conversion function template specialization. 1808Sema::TemplateDeductionResult 1809Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1810 QualType ToType, 1811 CXXConversionDecl *&Specialization, 1812 TemplateDeductionInfo &Info) { 1813 CXXConversionDecl *Conv 1814 = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()); 1815 QualType FromType = Conv->getConversionType(); 1816 1817 // Canonicalize the types for deduction. 1818 QualType P = Context.getCanonicalType(FromType); 1819 QualType A = Context.getCanonicalType(ToType); 1820 1821 // C++0x [temp.deduct.conv]p3: 1822 // If P is a reference type, the type referred to by P is used for 1823 // type deduction. 1824 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 1825 P = PRef->getPointeeType(); 1826 1827 // C++0x [temp.deduct.conv]p3: 1828 // If A is a reference type, the type referred to by A is used 1829 // for type deduction. 1830 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 1831 A = ARef->getPointeeType(); 1832 // C++ [temp.deduct.conv]p2: 1833 // 1834 // If A is not a reference type: 1835 else { 1836 assert(!A->isReferenceType() && "Reference types were handled above"); 1837 1838 // - If P is an array type, the pointer type produced by the 1839 // array-to-pointer standard conversion (4.2) is used in place 1840 // of P for type deduction; otherwise, 1841 if (P->isArrayType()) 1842 P = Context.getArrayDecayedType(P); 1843 // - If P is a function type, the pointer type produced by the 1844 // function-to-pointer standard conversion (4.3) is used in 1845 // place of P for type deduction; otherwise, 1846 else if (P->isFunctionType()) 1847 P = Context.getPointerType(P); 1848 // - If P is a cv-qualified type, the top level cv-qualifiers of 1849 // P’s type are ignored for type deduction. 1850 else 1851 P = P.getUnqualifiedType(); 1852 1853 // C++0x [temp.deduct.conv]p3: 1854 // If A is a cv-qualified type, the top level cv-qualifiers of A’s 1855 // type are ignored for type deduction. 1856 A = A.getUnqualifiedType(); 1857 } 1858 1859 // Template argument deduction for function templates in a SFINAE context. 1860 // Trap any errors that might occur. 1861 SFINAETrap Trap(*this); 1862 1863 // C++ [temp.deduct.conv]p1: 1864 // Template argument deduction is done by comparing the return 1865 // type of the template conversion function (call it P) with the 1866 // type that is required as the result of the conversion (call it 1867 // A) as described in 14.8.2.4. 1868 TemplateParameterList *TemplateParams 1869 = FunctionTemplate->getTemplateParameters(); 1870 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1871 Deduced.resize(TemplateParams->size()); 1872 1873 // C++0x [temp.deduct.conv]p4: 1874 // In general, the deduction process attempts to find template 1875 // argument values that will make the deduced A identical to 1876 // A. However, there are two cases that allow a difference: 1877 unsigned TDF = 0; 1878 // - If the original A is a reference type, A can be more 1879 // cv-qualified than the deduced A (i.e., the type referred to 1880 // by the reference) 1881 if (ToType->isReferenceType()) 1882 TDF |= TDF_ParamWithReferenceType; 1883 // - The deduced A can be another pointer or pointer to member 1884 // type that can be converted to A via a qualification 1885 // conversion. 1886 // 1887 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 1888 // both P and A are pointers or member pointers. In this case, we 1889 // just ignore cv-qualifiers completely). 1890 if ((P->isPointerType() && A->isPointerType()) || 1891 (P->isMemberPointerType() && P->isMemberPointerType())) 1892 TDF |= TDF_IgnoreQualifiers; 1893 if (TemplateDeductionResult Result 1894 = ::DeduceTemplateArguments(*this, TemplateParams, 1895 P, A, Info, Deduced, TDF)) 1896 return Result; 1897 1898 // FIXME: we need to check that the deduced A is the same as A, 1899 // modulo the various allowed differences. 1900 1901 // Finish template argument deduction. 1902 Sema::LocalInstantiationScope InstScope(*this); 1903 FunctionDecl *Spec = 0; 1904 TemplateDeductionResult Result 1905 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, 1906 Info); 1907 Specialization = cast_or_null<CXXConversionDecl>(Spec); 1908 return Result; 1909} 1910 1911/// \brief Deduce template arguments for a function template when there is 1912/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 1913/// 1914/// \param FunctionTemplate the function template for which we are performing 1915/// template argument deduction. 1916/// 1917/// \param ExplicitTemplateArguments the explicitly-specified template 1918/// arguments. 1919/// 1920/// \param Specialization if template argument deduction was successful, 1921/// this will be set to the function template specialization produced by 1922/// template argument deduction. 1923/// 1924/// \param Info the argument will be updated to provide additional information 1925/// about template argument deduction. 1926/// 1927/// \returns the result of template argument deduction. 1928Sema::TemplateDeductionResult 1929Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1930 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1931 FunctionDecl *&Specialization, 1932 TemplateDeductionInfo &Info) { 1933 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 1934 QualType(), Specialization, Info); 1935} 1936 1937/// \brief Stores the result of comparing the qualifiers of two types. 1938enum DeductionQualifierComparison { 1939 NeitherMoreQualified = 0, 1940 ParamMoreQualified, 1941 ArgMoreQualified 1942}; 1943 1944/// \brief Deduce the template arguments during partial ordering by comparing 1945/// the parameter type and the argument type (C++0x [temp.deduct.partial]). 1946/// 1947/// \param S the semantic analysis object within which we are deducing 1948/// 1949/// \param TemplateParams the template parameters that we are deducing 1950/// 1951/// \param ParamIn the parameter type 1952/// 1953/// \param ArgIn the argument type 1954/// 1955/// \param Info information about the template argument deduction itself 1956/// 1957/// \param Deduced the deduced template arguments 1958/// 1959/// \returns the result of template argument deduction so far. Note that a 1960/// "success" result means that template argument deduction has not yet failed, 1961/// but it may still fail, later, for other reasons. 1962static Sema::TemplateDeductionResult 1963DeduceTemplateArgumentsDuringPartialOrdering(Sema &S, 1964 TemplateParameterList *TemplateParams, 1965 QualType ParamIn, QualType ArgIn, 1966 Sema::TemplateDeductionInfo &Info, 1967 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1968 llvm::SmallVectorImpl<DeductionQualifierComparison> *QualifierComparisons) { 1969 CanQualType Param = S.Context.getCanonicalType(ParamIn); 1970 CanQualType Arg = S.Context.getCanonicalType(ArgIn); 1971 1972 // C++0x [temp.deduct.partial]p5: 1973 // Before the partial ordering is done, certain transformations are 1974 // performed on the types used for partial ordering: 1975 // - If P is a reference type, P is replaced by the type referred to. 1976 CanQual<ReferenceType> ParamRef = Param->getAs<ReferenceType>(); 1977 if (!ParamRef.isNull()) 1978 Param = ParamRef->getPointeeType(); 1979 1980 // - If A is a reference type, A is replaced by the type referred to. 1981 CanQual<ReferenceType> ArgRef = Arg->getAs<ReferenceType>(); 1982 if (!ArgRef.isNull()) 1983 Arg = ArgRef->getPointeeType(); 1984 1985 if (QualifierComparisons && !ParamRef.isNull() && !ArgRef.isNull()) { 1986 // C++0x [temp.deduct.partial]p6: 1987 // If both P and A were reference types (before being replaced with the 1988 // type referred to above), determine which of the two types (if any) is 1989 // more cv-qualified than the other; otherwise the types are considered to 1990 // be equally cv-qualified for partial ordering purposes. The result of this 1991 // determination will be used below. 1992 // 1993 // We save this information for later, using it only when deduction 1994 // succeeds in both directions. 1995 DeductionQualifierComparison QualifierResult = NeitherMoreQualified; 1996 if (Param.isMoreQualifiedThan(Arg)) 1997 QualifierResult = ParamMoreQualified; 1998 else if (Arg.isMoreQualifiedThan(Param)) 1999 QualifierResult = ArgMoreQualified; 2000 QualifierComparisons->push_back(QualifierResult); 2001 } 2002 2003 // C++0x [temp.deduct.partial]p7: 2004 // Remove any top-level cv-qualifiers: 2005 // - If P is a cv-qualified type, P is replaced by the cv-unqualified 2006 // version of P. 2007 Param = Param.getUnqualifiedType(); 2008 // - If A is a cv-qualified type, A is replaced by the cv-unqualified 2009 // version of A. 2010 Arg = Arg.getUnqualifiedType(); 2011 2012 // C++0x [temp.deduct.partial]p8: 2013 // Using the resulting types P and A the deduction is then done as 2014 // described in 14.9.2.5. If deduction succeeds for a given type, the type 2015 // from the argument template is considered to be at least as specialized 2016 // as the type from the parameter template. 2017 return DeduceTemplateArguments(S, TemplateParams, Param, Arg, Info, 2018 Deduced, TDF_None); 2019} 2020 2021static void 2022MarkUsedTemplateParameters(Sema &SemaRef, QualType T, 2023 bool OnlyDeduced, 2024 unsigned Level, 2025 llvm::SmallVectorImpl<bool> &Deduced); 2026 2027/// \brief Determine whether the function template \p FT1 is at least as 2028/// specialized as \p FT2. 2029static bool isAtLeastAsSpecializedAs(Sema &S, 2030 SourceLocation Loc, 2031 FunctionTemplateDecl *FT1, 2032 FunctionTemplateDecl *FT2, 2033 TemplatePartialOrderingContext TPOC, 2034 llvm::SmallVectorImpl<DeductionQualifierComparison> *QualifierComparisons) { 2035 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 2036 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 2037 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 2038 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 2039 2040 assert(Proto1 && Proto2 && "Function templates must have prototypes"); 2041 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 2042 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 2043 Deduced.resize(TemplateParams->size()); 2044 2045 // C++0x [temp.deduct.partial]p3: 2046 // The types used to determine the ordering depend on the context in which 2047 // the partial ordering is done: 2048 Sema::TemplateDeductionInfo Info(S.Context, Loc); 2049 switch (TPOC) { 2050 case TPOC_Call: { 2051 // - In the context of a function call, the function parameter types are 2052 // used. 2053 unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); 2054 for (unsigned I = 0; I != NumParams; ++I) 2055 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2056 TemplateParams, 2057 Proto2->getArgType(I), 2058 Proto1->getArgType(I), 2059 Info, 2060 Deduced, 2061 QualifierComparisons)) 2062 return false; 2063 2064 break; 2065 } 2066 2067 case TPOC_Conversion: 2068 // - In the context of a call to a conversion operator, the return types 2069 // of the conversion function templates are used. 2070 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2071 TemplateParams, 2072 Proto2->getResultType(), 2073 Proto1->getResultType(), 2074 Info, 2075 Deduced, 2076 QualifierComparisons)) 2077 return false; 2078 break; 2079 2080 case TPOC_Other: 2081 // - In other contexts (14.6.6.2) the function template’s function type 2082 // is used. 2083 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2084 TemplateParams, 2085 FD2->getType(), 2086 FD1->getType(), 2087 Info, 2088 Deduced, 2089 QualifierComparisons)) 2090 return false; 2091 break; 2092 } 2093 2094 // C++0x [temp.deduct.partial]p11: 2095 // In most cases, all template parameters must have values in order for 2096 // deduction to succeed, but for partial ordering purposes a template 2097 // parameter may remain without a value provided it is not used in the 2098 // types being used for partial ordering. [ Note: a template parameter used 2099 // in a non-deduced context is considered used. -end note] 2100 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 2101 for (; ArgIdx != NumArgs; ++ArgIdx) 2102 if (Deduced[ArgIdx].isNull()) 2103 break; 2104 2105 if (ArgIdx == NumArgs) { 2106 // All template arguments were deduced. FT1 is at least as specialized 2107 // as FT2. 2108 return true; 2109 } 2110 2111 // Figure out which template parameters were used. 2112 llvm::SmallVector<bool, 4> UsedParameters; 2113 UsedParameters.resize(TemplateParams->size()); 2114 switch (TPOC) { 2115 case TPOC_Call: { 2116 unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); 2117 for (unsigned I = 0; I != NumParams; ++I) 2118 ::MarkUsedTemplateParameters(S, Proto2->getArgType(I), false, 2119 TemplateParams->getDepth(), 2120 UsedParameters); 2121 break; 2122 } 2123 2124 case TPOC_Conversion: 2125 ::MarkUsedTemplateParameters(S, Proto2->getResultType(), false, 2126 TemplateParams->getDepth(), 2127 UsedParameters); 2128 break; 2129 2130 case TPOC_Other: 2131 ::MarkUsedTemplateParameters(S, FD2->getType(), false, 2132 TemplateParams->getDepth(), 2133 UsedParameters); 2134 break; 2135 } 2136 2137 for (; ArgIdx != NumArgs; ++ArgIdx) 2138 // If this argument had no value deduced but was used in one of the types 2139 // used for partial ordering, then deduction fails. 2140 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 2141 return false; 2142 2143 return true; 2144} 2145 2146 2147/// \brief Returns the more specialized function template according 2148/// to the rules of function template partial ordering (C++ [temp.func.order]). 2149/// 2150/// \param FT1 the first function template 2151/// 2152/// \param FT2 the second function template 2153/// 2154/// \param TPOC the context in which we are performing partial ordering of 2155/// function templates. 2156/// 2157/// \returns the more specialized function template. If neither 2158/// template is more specialized, returns NULL. 2159FunctionTemplateDecl * 2160Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 2161 FunctionTemplateDecl *FT2, 2162 SourceLocation Loc, 2163 TemplatePartialOrderingContext TPOC) { 2164 llvm::SmallVector<DeductionQualifierComparison, 4> QualifierComparisons; 2165 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 0); 2166 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 2167 &QualifierComparisons); 2168 2169 if (Better1 != Better2) // We have a clear winner 2170 return Better1? FT1 : FT2; 2171 2172 if (!Better1 && !Better2) // Neither is better than the other 2173 return 0; 2174 2175 2176 // C++0x [temp.deduct.partial]p10: 2177 // If for each type being considered a given template is at least as 2178 // specialized for all types and more specialized for some set of types and 2179 // the other template is not more specialized for any types or is not at 2180 // least as specialized for any types, then the given template is more 2181 // specialized than the other template. Otherwise, neither template is more 2182 // specialized than the other. 2183 Better1 = false; 2184 Better2 = false; 2185 for (unsigned I = 0, N = QualifierComparisons.size(); I != N; ++I) { 2186 // C++0x [temp.deduct.partial]p9: 2187 // If, for a given type, deduction succeeds in both directions (i.e., the 2188 // types are identical after the transformations above) and if the type 2189 // from the argument template is more cv-qualified than the type from the 2190 // parameter template (as described above) that type is considered to be 2191 // more specialized than the other. If neither type is more cv-qualified 2192 // than the other then neither type is more specialized than the other. 2193 switch (QualifierComparisons[I]) { 2194 case NeitherMoreQualified: 2195 break; 2196 2197 case ParamMoreQualified: 2198 Better1 = true; 2199 if (Better2) 2200 return 0; 2201 break; 2202 2203 case ArgMoreQualified: 2204 Better2 = true; 2205 if (Better1) 2206 return 0; 2207 break; 2208 } 2209 } 2210 2211 assert(!(Better1 && Better2) && "Should have broken out in the loop above"); 2212 if (Better1) 2213 return FT1; 2214 else if (Better2) 2215 return FT2; 2216 else 2217 return 0; 2218} 2219 2220/// \brief Determine if the two templates are equivalent. 2221static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 2222 if (T1 == T2) 2223 return true; 2224 2225 if (!T1 || !T2) 2226 return false; 2227 2228 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 2229} 2230 2231/// \brief Retrieve the most specialized of the given function template 2232/// specializations. 2233/// 2234/// \param SpecBegin the start iterator of the function template 2235/// specializations that we will be comparing. 2236/// 2237/// \param SpecEnd the end iterator of the function template 2238/// specializations, paired with \p SpecBegin. 2239/// 2240/// \param TPOC the partial ordering context to use to compare the function 2241/// template specializations. 2242/// 2243/// \param Loc the location where the ambiguity or no-specializations 2244/// diagnostic should occur. 2245/// 2246/// \param NoneDiag partial diagnostic used to diagnose cases where there are 2247/// no matching candidates. 2248/// 2249/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 2250/// occurs. 2251/// 2252/// \param CandidateDiag partial diagnostic used for each function template 2253/// specialization that is a candidate in the ambiguous ordering. One parameter 2254/// in this diagnostic should be unbound, which will correspond to the string 2255/// describing the template arguments for the function template specialization. 2256/// 2257/// \param Index if non-NULL and the result of this function is non-nULL, 2258/// receives the index corresponding to the resulting function template 2259/// specialization. 2260/// 2261/// \returns the most specialized function template specialization, if 2262/// found. Otherwise, returns SpecEnd. 2263/// 2264/// \todo FIXME: Consider passing in the "also-ran" candidates that failed 2265/// template argument deduction. 2266UnresolvedSetIterator 2267Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, 2268 UnresolvedSetIterator SpecEnd, 2269 TemplatePartialOrderingContext TPOC, 2270 SourceLocation Loc, 2271 const PartialDiagnostic &NoneDiag, 2272 const PartialDiagnostic &AmbigDiag, 2273 const PartialDiagnostic &CandidateDiag) { 2274 if (SpecBegin == SpecEnd) { 2275 Diag(Loc, NoneDiag); 2276 return SpecEnd; 2277 } 2278 2279 if (SpecBegin + 1 == SpecEnd) 2280 return SpecBegin; 2281 2282 // Find the function template that is better than all of the templates it 2283 // has been compared to. 2284 UnresolvedSetIterator Best = SpecBegin; 2285 FunctionTemplateDecl *BestTemplate 2286 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 2287 assert(BestTemplate && "Not a function template specialization?"); 2288 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 2289 FunctionTemplateDecl *Challenger 2290 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 2291 assert(Challenger && "Not a function template specialization?"); 2292 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 2293 Loc, TPOC), 2294 Challenger)) { 2295 Best = I; 2296 BestTemplate = Challenger; 2297 } 2298 } 2299 2300 // Make sure that the "best" function template is more specialized than all 2301 // of the others. 2302 bool Ambiguous = false; 2303 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 2304 FunctionTemplateDecl *Challenger 2305 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 2306 if (I != Best && 2307 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 2308 Loc, TPOC), 2309 BestTemplate)) { 2310 Ambiguous = true; 2311 break; 2312 } 2313 } 2314 2315 if (!Ambiguous) { 2316 // We found an answer. Return it. 2317 return Best; 2318 } 2319 2320 // Diagnose the ambiguity. 2321 Diag(Loc, AmbigDiag); 2322 2323 // FIXME: Can we order the candidates in some sane way? 2324 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) 2325 Diag((*I)->getLocation(), CandidateDiag) 2326 << getTemplateArgumentBindingsText( 2327 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(), 2328 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs()); 2329 2330 return SpecEnd; 2331} 2332 2333/// \brief Returns the more specialized class template partial specialization 2334/// according to the rules of partial ordering of class template partial 2335/// specializations (C++ [temp.class.order]). 2336/// 2337/// \param PS1 the first class template partial specialization 2338/// 2339/// \param PS2 the second class template partial specialization 2340/// 2341/// \returns the more specialized class template partial specialization. If 2342/// neither partial specialization is more specialized, returns NULL. 2343ClassTemplatePartialSpecializationDecl * 2344Sema::getMoreSpecializedPartialSpecialization( 2345 ClassTemplatePartialSpecializationDecl *PS1, 2346 ClassTemplatePartialSpecializationDecl *PS2, 2347 SourceLocation Loc) { 2348 // C++ [temp.class.order]p1: 2349 // For two class template partial specializations, the first is at least as 2350 // specialized as the second if, given the following rewrite to two 2351 // function templates, the first function template is at least as 2352 // specialized as the second according to the ordering rules for function 2353 // templates (14.6.6.2): 2354 // - the first function template has the same template parameters as the 2355 // first partial specialization and has a single function parameter 2356 // whose type is a class template specialization with the template 2357 // arguments of the first partial specialization, and 2358 // - the second function template has the same template parameters as the 2359 // second partial specialization and has a single function parameter 2360 // whose type is a class template specialization with the template 2361 // arguments of the second partial specialization. 2362 // 2363 // Rather than synthesize function templates, we merely perform the 2364 // equivalent partial ordering by performing deduction directly on 2365 // the template arguments of the class template partial 2366 // specializations. This computation is slightly simpler than the 2367 // general problem of function template partial ordering, because 2368 // class template partial specializations are more constrained. We 2369 // know that every template parameter is deducible from the class 2370 // template partial specialization's template arguments, for 2371 // example. 2372 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 2373 Sema::TemplateDeductionInfo Info(Context, Loc); 2374 2375 QualType PT1 = PS1->getInjectedSpecializationType(); 2376 QualType PT2 = PS2->getInjectedSpecializationType(); 2377 2378 // Determine whether PS1 is at least as specialized as PS2 2379 Deduced.resize(PS2->getTemplateParameters()->size()); 2380 bool Better1 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, 2381 PS2->getTemplateParameters(), 2382 PT2, 2383 PT1, 2384 Info, 2385 Deduced, 2386 0); 2387 if (Better1) 2388 Better1 = !::FinishTemplateArgumentDeduction(*this, PS2, 2389 PS1->getTemplateArgs(), 2390 Deduced, Info); 2391 2392 // Determine whether PS2 is at least as specialized as PS1 2393 Deduced.clear(); 2394 Deduced.resize(PS1->getTemplateParameters()->size()); 2395 bool Better2 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, 2396 PS1->getTemplateParameters(), 2397 PT1, 2398 PT2, 2399 Info, 2400 Deduced, 2401 0); 2402 if (Better2) 2403 Better2 = !::FinishTemplateArgumentDeduction(*this, PS1, 2404 PS2->getTemplateArgs(), 2405 Deduced, Info); 2406 2407 if (Better1 == Better2) 2408 return 0; 2409 2410 return Better1? PS1 : PS2; 2411} 2412 2413static void 2414MarkUsedTemplateParameters(Sema &SemaRef, 2415 const TemplateArgument &TemplateArg, 2416 bool OnlyDeduced, 2417 unsigned Depth, 2418 llvm::SmallVectorImpl<bool> &Used); 2419 2420/// \brief Mark the template parameters that are used by the given 2421/// expression. 2422static void 2423MarkUsedTemplateParameters(Sema &SemaRef, 2424 const Expr *E, 2425 bool OnlyDeduced, 2426 unsigned Depth, 2427 llvm::SmallVectorImpl<bool> &Used) { 2428 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to 2429 // find other occurrences of template parameters. 2430 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E); 2431 if (!DRE) 2432 return; 2433 2434 const NonTypeTemplateParmDecl *NTTP 2435 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 2436 if (!NTTP) 2437 return; 2438 2439 if (NTTP->getDepth() == Depth) 2440 Used[NTTP->getIndex()] = true; 2441} 2442 2443/// \brief Mark the template parameters that are used by the given 2444/// nested name specifier. 2445static void 2446MarkUsedTemplateParameters(Sema &SemaRef, 2447 NestedNameSpecifier *NNS, 2448 bool OnlyDeduced, 2449 unsigned Depth, 2450 llvm::SmallVectorImpl<bool> &Used) { 2451 if (!NNS) 2452 return; 2453 2454 MarkUsedTemplateParameters(SemaRef, NNS->getPrefix(), OnlyDeduced, Depth, 2455 Used); 2456 MarkUsedTemplateParameters(SemaRef, QualType(NNS->getAsType(), 0), 2457 OnlyDeduced, Depth, Used); 2458} 2459 2460/// \brief Mark the template parameters that are used by the given 2461/// template name. 2462static void 2463MarkUsedTemplateParameters(Sema &SemaRef, 2464 TemplateName Name, 2465 bool OnlyDeduced, 2466 unsigned Depth, 2467 llvm::SmallVectorImpl<bool> &Used) { 2468 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 2469 if (TemplateTemplateParmDecl *TTP 2470 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 2471 if (TTP->getDepth() == Depth) 2472 Used[TTP->getIndex()] = true; 2473 } 2474 return; 2475 } 2476 2477 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 2478 MarkUsedTemplateParameters(SemaRef, QTN->getQualifier(), OnlyDeduced, 2479 Depth, Used); 2480 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 2481 MarkUsedTemplateParameters(SemaRef, DTN->getQualifier(), OnlyDeduced, 2482 Depth, Used); 2483} 2484 2485/// \brief Mark the template parameters that are used by the given 2486/// type. 2487static void 2488MarkUsedTemplateParameters(Sema &SemaRef, QualType T, 2489 bool OnlyDeduced, 2490 unsigned Depth, 2491 llvm::SmallVectorImpl<bool> &Used) { 2492 if (T.isNull()) 2493 return; 2494 2495 // Non-dependent types have nothing deducible 2496 if (!T->isDependentType()) 2497 return; 2498 2499 T = SemaRef.Context.getCanonicalType(T); 2500 switch (T->getTypeClass()) { 2501 case Type::Pointer: 2502 MarkUsedTemplateParameters(SemaRef, 2503 cast<PointerType>(T)->getPointeeType(), 2504 OnlyDeduced, 2505 Depth, 2506 Used); 2507 break; 2508 2509 case Type::BlockPointer: 2510 MarkUsedTemplateParameters(SemaRef, 2511 cast<BlockPointerType>(T)->getPointeeType(), 2512 OnlyDeduced, 2513 Depth, 2514 Used); 2515 break; 2516 2517 case Type::LValueReference: 2518 case Type::RValueReference: 2519 MarkUsedTemplateParameters(SemaRef, 2520 cast<ReferenceType>(T)->getPointeeType(), 2521 OnlyDeduced, 2522 Depth, 2523 Used); 2524 break; 2525 2526 case Type::MemberPointer: { 2527 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 2528 MarkUsedTemplateParameters(SemaRef, MemPtr->getPointeeType(), OnlyDeduced, 2529 Depth, Used); 2530 MarkUsedTemplateParameters(SemaRef, QualType(MemPtr->getClass(), 0), 2531 OnlyDeduced, Depth, Used); 2532 break; 2533 } 2534 2535 case Type::DependentSizedArray: 2536 MarkUsedTemplateParameters(SemaRef, 2537 cast<DependentSizedArrayType>(T)->getSizeExpr(), 2538 OnlyDeduced, Depth, Used); 2539 // Fall through to check the element type 2540 2541 case Type::ConstantArray: 2542 case Type::IncompleteArray: 2543 MarkUsedTemplateParameters(SemaRef, 2544 cast<ArrayType>(T)->getElementType(), 2545 OnlyDeduced, Depth, Used); 2546 break; 2547 2548 case Type::Vector: 2549 case Type::ExtVector: 2550 MarkUsedTemplateParameters(SemaRef, 2551 cast<VectorType>(T)->getElementType(), 2552 OnlyDeduced, Depth, Used); 2553 break; 2554 2555 case Type::DependentSizedExtVector: { 2556 const DependentSizedExtVectorType *VecType 2557 = cast<DependentSizedExtVectorType>(T); 2558 MarkUsedTemplateParameters(SemaRef, VecType->getElementType(), OnlyDeduced, 2559 Depth, Used); 2560 MarkUsedTemplateParameters(SemaRef, VecType->getSizeExpr(), OnlyDeduced, 2561 Depth, Used); 2562 break; 2563 } 2564 2565 case Type::FunctionProto: { 2566 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 2567 MarkUsedTemplateParameters(SemaRef, Proto->getResultType(), OnlyDeduced, 2568 Depth, Used); 2569 for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) 2570 MarkUsedTemplateParameters(SemaRef, Proto->getArgType(I), OnlyDeduced, 2571 Depth, Used); 2572 break; 2573 } 2574 2575 case Type::TemplateTypeParm: { 2576 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 2577 if (TTP->getDepth() == Depth) 2578 Used[TTP->getIndex()] = true; 2579 break; 2580 } 2581 2582 case Type::InjectedClassName: 2583 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 2584 // fall through 2585 2586 case Type::TemplateSpecialization: { 2587 const TemplateSpecializationType *Spec 2588 = cast<TemplateSpecializationType>(T); 2589 MarkUsedTemplateParameters(SemaRef, Spec->getTemplateName(), OnlyDeduced, 2590 Depth, Used); 2591 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 2592 MarkUsedTemplateParameters(SemaRef, Spec->getArg(I), OnlyDeduced, Depth, 2593 Used); 2594 break; 2595 } 2596 2597 case Type::Complex: 2598 if (!OnlyDeduced) 2599 MarkUsedTemplateParameters(SemaRef, 2600 cast<ComplexType>(T)->getElementType(), 2601 OnlyDeduced, Depth, Used); 2602 break; 2603 2604 case Type::DependentName: 2605 if (!OnlyDeduced) 2606 MarkUsedTemplateParameters(SemaRef, 2607 cast<DependentNameType>(T)->getQualifier(), 2608 OnlyDeduced, Depth, Used); 2609 break; 2610 2611 case Type::TypeOf: 2612 if (!OnlyDeduced) 2613 MarkUsedTemplateParameters(SemaRef, 2614 cast<TypeOfType>(T)->getUnderlyingType(), 2615 OnlyDeduced, Depth, Used); 2616 break; 2617 2618 case Type::TypeOfExpr: 2619 if (!OnlyDeduced) 2620 MarkUsedTemplateParameters(SemaRef, 2621 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 2622 OnlyDeduced, Depth, Used); 2623 break; 2624 2625 case Type::Decltype: 2626 if (!OnlyDeduced) 2627 MarkUsedTemplateParameters(SemaRef, 2628 cast<DecltypeType>(T)->getUnderlyingExpr(), 2629 OnlyDeduced, Depth, Used); 2630 break; 2631 2632 // None of these types have any template parameters in them. 2633 case Type::Builtin: 2634 case Type::VariableArray: 2635 case Type::FunctionNoProto: 2636 case Type::Record: 2637 case Type::Enum: 2638 case Type::ObjCInterface: 2639 case Type::ObjCObjectPointer: 2640 case Type::UnresolvedUsing: 2641#define TYPE(Class, Base) 2642#define ABSTRACT_TYPE(Class, Base) 2643#define DEPENDENT_TYPE(Class, Base) 2644#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 2645#include "clang/AST/TypeNodes.def" 2646 break; 2647 } 2648} 2649 2650/// \brief Mark the template parameters that are used by this 2651/// template argument. 2652static void 2653MarkUsedTemplateParameters(Sema &SemaRef, 2654 const TemplateArgument &TemplateArg, 2655 bool OnlyDeduced, 2656 unsigned Depth, 2657 llvm::SmallVectorImpl<bool> &Used) { 2658 switch (TemplateArg.getKind()) { 2659 case TemplateArgument::Null: 2660 case TemplateArgument::Integral: 2661 case TemplateArgument::Declaration: 2662 break; 2663 2664 case TemplateArgument::Type: 2665 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsType(), OnlyDeduced, 2666 Depth, Used); 2667 break; 2668 2669 case TemplateArgument::Template: 2670 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsTemplate(), 2671 OnlyDeduced, Depth, Used); 2672 break; 2673 2674 case TemplateArgument::Expression: 2675 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsExpr(), OnlyDeduced, 2676 Depth, Used); 2677 break; 2678 2679 case TemplateArgument::Pack: 2680 for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), 2681 PEnd = TemplateArg.pack_end(); 2682 P != PEnd; ++P) 2683 MarkUsedTemplateParameters(SemaRef, *P, OnlyDeduced, Depth, Used); 2684 break; 2685 } 2686} 2687 2688/// \brief Mark the template parameters can be deduced by the given 2689/// template argument list. 2690/// 2691/// \param TemplateArgs the template argument list from which template 2692/// parameters will be deduced. 2693/// 2694/// \param Deduced a bit vector whose elements will be set to \c true 2695/// to indicate when the corresponding template parameter will be 2696/// deduced. 2697void 2698Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 2699 bool OnlyDeduced, unsigned Depth, 2700 llvm::SmallVectorImpl<bool> &Used) { 2701 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 2702 ::MarkUsedTemplateParameters(*this, TemplateArgs[I], OnlyDeduced, 2703 Depth, Used); 2704} 2705 2706/// \brief Marks all of the template parameters that will be deduced by a 2707/// call to the given function template. 2708void 2709Sema::MarkDeducedTemplateParameters(FunctionTemplateDecl *FunctionTemplate, 2710 llvm::SmallVectorImpl<bool> &Deduced) { 2711 TemplateParameterList *TemplateParams 2712 = FunctionTemplate->getTemplateParameters(); 2713 Deduced.clear(); 2714 Deduced.resize(TemplateParams->size()); 2715 2716 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2717 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 2718 ::MarkUsedTemplateParameters(*this, Function->getParamDecl(I)->getType(), 2719 true, TemplateParams->getDepth(), Deduced); 2720} 2721