SemaTemplateDeduction.cpp revision 8d8e5ce078d62be1e745d4a94b963c885c77958e
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/// \brief Perform template argument deduction to determine whether 965/// the given template arguments match the given class template 966/// partial specialization per C++ [temp.class.spec.match]. 967Sema::TemplateDeductionResult 968Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial, 969 const TemplateArgumentList &TemplateArgs, 970 TemplateDeductionInfo &Info) { 971 // C++ [temp.class.spec.match]p2: 972 // A partial specialization matches a given actual template 973 // argument list if the template arguments of the partial 974 // specialization can be deduced from the actual template argument 975 // list (14.8.2). 976 SFINAETrap Trap(*this); 977 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 978 Deduced.resize(Partial->getTemplateParameters()->size()); 979 if (TemplateDeductionResult Result 980 = ::DeduceTemplateArguments(*this, 981 Partial->getTemplateParameters(), 982 Partial->getTemplateArgs(), 983 TemplateArgs, Info, Deduced)) 984 return Result; 985 986 InstantiatingTemplate Inst(*this, Partial->getLocation(), Partial, 987 Deduced.data(), Deduced.size()); 988 if (Inst) 989 return TDK_InstantiationDepth; 990 991 ContextRAII SavedContext(*this, Partial->getDeclContext()); 992 993 // C++ [temp.deduct.type]p2: 994 // [...] or if any template argument remains neither deduced nor 995 // explicitly specified, template argument deduction fails. 996 TemplateArgumentListBuilder Builder(Partial->getTemplateParameters(), 997 Deduced.size()); 998 for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { 999 if (Deduced[I].isNull()) { 1000 Decl *Param 1001 = const_cast<NamedDecl *>( 1002 Partial->getTemplateParameters()->getParam(I)); 1003 Info.Param = makeTemplateParameter(Param); 1004 return TDK_Incomplete; 1005 } 1006 1007 Builder.Append(Deduced[I]); 1008 } 1009 1010 // Form the template argument list from the deduced template arguments. 1011 TemplateArgumentList *DeducedArgumentList 1012 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1013 Info.reset(DeducedArgumentList); 1014 1015 // Substitute the deduced template arguments into the template 1016 // arguments of the class template partial specialization, and 1017 // verify that the instantiated template arguments are both valid 1018 // and are equivalent to the template arguments originally provided 1019 // to the class template. 1020 // FIXME: Do we have to correct the types of deduced non-type template 1021 // arguments (in particular, integral non-type template arguments?). 1022 Sema::LocalInstantiationScope InstScope(*this); 1023 ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate(); 1024 const TemplateArgumentLoc *PartialTemplateArgs 1025 = Partial->getTemplateArgsAsWritten(); 1026 unsigned N = Partial->getNumTemplateArgsAsWritten(); 1027 1028 // Note that we don't provide the langle and rangle locations. 1029 TemplateArgumentListInfo InstArgs; 1030 1031 for (unsigned I = 0; I != N; ++I) { 1032 Decl *Param = const_cast<NamedDecl *>( 1033 ClassTemplate->getTemplateParameters()->getParam(I)); 1034 TemplateArgumentLoc InstArg; 1035 if (Subst(PartialTemplateArgs[I], InstArg, 1036 MultiLevelTemplateArgumentList(*DeducedArgumentList))) { 1037 Info.Param = makeTemplateParameter(Param); 1038 Info.FirstArg = PartialTemplateArgs[I].getArgument(); 1039 return TDK_SubstitutionFailure; 1040 } 1041 InstArgs.addArgument(InstArg); 1042 } 1043 1044 TemplateArgumentListBuilder ConvertedInstArgs( 1045 ClassTemplate->getTemplateParameters(), N); 1046 1047 if (CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(), 1048 InstArgs, false, ConvertedInstArgs)) { 1049 // FIXME: fail with more useful information? 1050 return TDK_SubstitutionFailure; 1051 } 1052 1053 for (unsigned I = 0, E = ConvertedInstArgs.flatSize(); I != E; ++I) { 1054 TemplateArgument InstArg = ConvertedInstArgs.getFlatArguments()[I]; 1055 1056 Decl *Param = const_cast<NamedDecl *>( 1057 ClassTemplate->getTemplateParameters()->getParam(I)); 1058 1059 if (InstArg.getKind() == TemplateArgument::Expression) { 1060 // When the argument is an expression, check the expression result 1061 // against the actual template parameter to get down to the canonical 1062 // template argument. 1063 Expr *InstExpr = InstArg.getAsExpr(); 1064 if (NonTypeTemplateParmDecl *NTTP 1065 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 1066 if (CheckTemplateArgument(NTTP, NTTP->getType(), InstExpr, InstArg)) { 1067 Info.Param = makeTemplateParameter(Param); 1068 Info.FirstArg = Partial->getTemplateArgs()[I]; 1069 return TDK_SubstitutionFailure; 1070 } 1071 } 1072 } 1073 1074 if (!isSameTemplateArg(Context, TemplateArgs[I], InstArg)) { 1075 Info.Param = makeTemplateParameter(Param); 1076 Info.FirstArg = TemplateArgs[I]; 1077 Info.SecondArg = InstArg; 1078 return TDK_NonDeducedMismatch; 1079 } 1080 } 1081 1082 if (Trap.hasErrorOccurred()) 1083 return TDK_SubstitutionFailure; 1084 1085 return TDK_Success; 1086} 1087 1088/// \brief Determine whether the given type T is a simple-template-id type. 1089static bool isSimpleTemplateIdType(QualType T) { 1090 if (const TemplateSpecializationType *Spec 1091 = T->getAs<TemplateSpecializationType>()) 1092 return Spec->getTemplateName().getAsTemplateDecl() != 0; 1093 1094 return false; 1095} 1096 1097/// \brief Substitute the explicitly-provided template arguments into the 1098/// given function template according to C++ [temp.arg.explicit]. 1099/// 1100/// \param FunctionTemplate the function template into which the explicit 1101/// template arguments will be substituted. 1102/// 1103/// \param ExplicitTemplateArguments the explicitly-specified template 1104/// arguments. 1105/// 1106/// \param Deduced the deduced template arguments, which will be populated 1107/// with the converted and checked explicit template arguments. 1108/// 1109/// \param ParamTypes will be populated with the instantiated function 1110/// parameters. 1111/// 1112/// \param FunctionType if non-NULL, the result type of the function template 1113/// will also be instantiated and the pointed-to value will be updated with 1114/// the instantiated function type. 1115/// 1116/// \param Info if substitution fails for any reason, this object will be 1117/// populated with more information about the failure. 1118/// 1119/// \returns TDK_Success if substitution was successful, or some failure 1120/// condition. 1121Sema::TemplateDeductionResult 1122Sema::SubstituteExplicitTemplateArguments( 1123 FunctionTemplateDecl *FunctionTemplate, 1124 const TemplateArgumentListInfo &ExplicitTemplateArgs, 1125 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1126 llvm::SmallVectorImpl<QualType> &ParamTypes, 1127 QualType *FunctionType, 1128 TemplateDeductionInfo &Info) { 1129 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1130 TemplateParameterList *TemplateParams 1131 = FunctionTemplate->getTemplateParameters(); 1132 1133 if (ExplicitTemplateArgs.size() == 0) { 1134 // No arguments to substitute; just copy over the parameter types and 1135 // fill in the function type. 1136 for (FunctionDecl::param_iterator P = Function->param_begin(), 1137 PEnd = Function->param_end(); 1138 P != PEnd; 1139 ++P) 1140 ParamTypes.push_back((*P)->getType()); 1141 1142 if (FunctionType) 1143 *FunctionType = Function->getType(); 1144 return TDK_Success; 1145 } 1146 1147 // Substitution of the explicit template arguments into a function template 1148 /// is a SFINAE context. Trap any errors that might occur. 1149 SFINAETrap Trap(*this); 1150 1151 // C++ [temp.arg.explicit]p3: 1152 // Template arguments that are present shall be specified in the 1153 // declaration order of their corresponding template-parameters. The 1154 // template argument list shall not specify more template-arguments than 1155 // there are corresponding template-parameters. 1156 TemplateArgumentListBuilder Builder(TemplateParams, 1157 ExplicitTemplateArgs.size()); 1158 1159 // Enter a new template instantiation context where we check the 1160 // explicitly-specified template arguments against this function template, 1161 // and then substitute them into the function parameter types. 1162 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 1163 FunctionTemplate, Deduced.data(), Deduced.size(), 1164 ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution); 1165 if (Inst) 1166 return TDK_InstantiationDepth; 1167 1168 ContextRAII SavedContext(*this, FunctionTemplate->getDeclContext()); 1169 1170 if (CheckTemplateArgumentList(FunctionTemplate, 1171 SourceLocation(), 1172 ExplicitTemplateArgs, 1173 true, 1174 Builder) || Trap.hasErrorOccurred()) 1175 return TDK_InvalidExplicitArguments; 1176 1177 // Form the template argument list from the explicitly-specified 1178 // template arguments. 1179 TemplateArgumentList *ExplicitArgumentList 1180 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1181 Info.reset(ExplicitArgumentList); 1182 1183 // Instantiate the types of each of the function parameters given the 1184 // explicitly-specified template arguments. 1185 for (FunctionDecl::param_iterator P = Function->param_begin(), 1186 PEnd = Function->param_end(); 1187 P != PEnd; 1188 ++P) { 1189 QualType ParamType 1190 = SubstType((*P)->getType(), 1191 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 1192 (*P)->getLocation(), (*P)->getDeclName()); 1193 if (ParamType.isNull() || Trap.hasErrorOccurred()) 1194 return TDK_SubstitutionFailure; 1195 1196 ParamTypes.push_back(ParamType); 1197 } 1198 1199 // If the caller wants a full function type back, instantiate the return 1200 // type and form that function type. 1201 if (FunctionType) { 1202 // FIXME: exception-specifications? 1203 const FunctionProtoType *Proto 1204 = Function->getType()->getAs<FunctionProtoType>(); 1205 assert(Proto && "Function template does not have a prototype?"); 1206 1207 QualType ResultType 1208 = SubstType(Proto->getResultType(), 1209 MultiLevelTemplateArgumentList(*ExplicitArgumentList), 1210 Function->getTypeSpecStartLoc(), 1211 Function->getDeclName()); 1212 if (ResultType.isNull() || Trap.hasErrorOccurred()) 1213 return TDK_SubstitutionFailure; 1214 1215 *FunctionType = BuildFunctionType(ResultType, 1216 ParamTypes.data(), ParamTypes.size(), 1217 Proto->isVariadic(), 1218 Proto->getTypeQuals(), 1219 Function->getLocation(), 1220 Function->getDeclName()); 1221 if (FunctionType->isNull() || Trap.hasErrorOccurred()) 1222 return TDK_SubstitutionFailure; 1223 } 1224 1225 // C++ [temp.arg.explicit]p2: 1226 // Trailing template arguments that can be deduced (14.8.2) may be 1227 // omitted from the list of explicit template-arguments. If all of the 1228 // template arguments can be deduced, they may all be omitted; in this 1229 // case, the empty template argument list <> itself may also be omitted. 1230 // 1231 // Take all of the explicitly-specified arguments and put them into the 1232 // set of deduced template arguments. 1233 Deduced.reserve(TemplateParams->size()); 1234 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) 1235 Deduced.push_back(ExplicitArgumentList->get(I)); 1236 1237 return TDK_Success; 1238} 1239 1240/// \brief Allocate a TemplateArgumentLoc where all locations have 1241/// been initialized to the given location. 1242/// 1243/// \param S The semantic analysis object. 1244/// 1245/// \param The template argument we are producing template argument 1246/// location information for. 1247/// 1248/// \param NTTPType For a declaration template argument, the type of 1249/// the non-type template parameter that corresponds to this template 1250/// argument. 1251/// 1252/// \param Loc The source location to use for the resulting template 1253/// argument. 1254static TemplateArgumentLoc 1255getTrivialTemplateArgumentLoc(Sema &S, 1256 const TemplateArgument &Arg, 1257 QualType NTTPType, 1258 SourceLocation Loc) { 1259 switch (Arg.getKind()) { 1260 case TemplateArgument::Null: 1261 llvm_unreachable("Can't get a NULL template argument here"); 1262 break; 1263 1264 case TemplateArgument::Type: 1265 return TemplateArgumentLoc(Arg, 1266 S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc)); 1267 1268 case TemplateArgument::Declaration: { 1269 Expr *E 1270 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc) 1271 .takeAs<Expr>(); 1272 return TemplateArgumentLoc(TemplateArgument(E), E); 1273 } 1274 1275 case TemplateArgument::Integral: { 1276 Expr *E 1277 = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>(); 1278 return TemplateArgumentLoc(TemplateArgument(E), E); 1279 } 1280 1281 case TemplateArgument::Template: 1282 return TemplateArgumentLoc(Arg, SourceRange(), Loc); 1283 1284 case TemplateArgument::Expression: 1285 return TemplateArgumentLoc(Arg, Arg.getAsExpr()); 1286 1287 case TemplateArgument::Pack: 1288 llvm_unreachable("Template parameter packs are not yet supported"); 1289 } 1290 1291 return TemplateArgumentLoc(); 1292} 1293 1294/// \brief Finish template argument deduction for a function template, 1295/// checking the deduced template arguments for completeness and forming 1296/// the function template specialization. 1297Sema::TemplateDeductionResult 1298Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate, 1299 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1300 unsigned NumExplicitlySpecified, 1301 FunctionDecl *&Specialization, 1302 TemplateDeductionInfo &Info) { 1303 TemplateParameterList *TemplateParams 1304 = FunctionTemplate->getTemplateParameters(); 1305 1306 // Template argument deduction for function templates in a SFINAE context. 1307 // Trap any errors that might occur. 1308 SFINAETrap Trap(*this); 1309 1310 // Enter a new template instantiation context while we instantiate the 1311 // actual function declaration. 1312 InstantiatingTemplate Inst(*this, FunctionTemplate->getLocation(), 1313 FunctionTemplate, Deduced.data(), Deduced.size(), 1314 ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution); 1315 if (Inst) 1316 return TDK_InstantiationDepth; 1317 1318 ContextRAII SavedContext(*this, FunctionTemplate->getDeclContext()); 1319 1320 // C++ [temp.deduct.type]p2: 1321 // [...] or if any template argument remains neither deduced nor 1322 // explicitly specified, template argument deduction fails. 1323 TemplateArgumentListBuilder Builder(TemplateParams, Deduced.size()); 1324 for (unsigned I = 0, N = Deduced.size(); I != N; ++I) { 1325 NamedDecl *Param = FunctionTemplate->getTemplateParameters()->getParam(I); 1326 if (!Deduced[I].isNull()) { 1327 if (I < NumExplicitlySpecified || 1328 Deduced[I].getKind() == TemplateArgument::Type) { 1329 // We have already fully type-checked and converted this 1330 // argument (because it was explicitly-specified) or no 1331 // additional checking is necessary (because it's a template 1332 // type parameter). Just record the presence of this 1333 // parameter. 1334 Builder.Append(Deduced[I]); 1335 continue; 1336 } 1337 1338 // We have deduced this argument, so it still needs to be 1339 // checked and converted. 1340 1341 // First, for a non-type template parameter type that is 1342 // initialized by a declaration, we need the type of the 1343 // corresponding non-type template parameter. 1344 QualType NTTPType; 1345 if (NonTypeTemplateParmDecl *NTTP 1346 = dyn_cast<NonTypeTemplateParmDecl>(Param)) { 1347 if (Deduced[I].getKind() == TemplateArgument::Declaration) { 1348 NTTPType = NTTP->getType(); 1349 if (NTTPType->isDependentType()) { 1350 TemplateArgumentList TemplateArgs(Context, Builder, 1351 /*TakeArgs=*/false); 1352 NTTPType = SubstType(NTTPType, 1353 MultiLevelTemplateArgumentList(TemplateArgs), 1354 NTTP->getLocation(), 1355 NTTP->getDeclName()); 1356 if (NTTPType.isNull()) { 1357 Info.Param = makeTemplateParameter(Param); 1358 return TDK_SubstitutionFailure; 1359 } 1360 } 1361 } 1362 } 1363 1364 // Convert the deduced template argument into a template 1365 // argument that we can check, almost as if the user had written 1366 // the template argument explicitly. 1367 TemplateArgumentLoc Arg = getTrivialTemplateArgumentLoc(*this, 1368 Deduced[I], 1369 NTTPType, 1370 SourceLocation()); 1371 1372 // Check the template argument, converting it as necessary. 1373 if (CheckTemplateArgument(Param, Arg, 1374 FunctionTemplate, 1375 FunctionTemplate->getLocation(), 1376 FunctionTemplate->getSourceRange().getEnd(), 1377 Builder, 1378 Deduced[I].wasDeducedFromArrayBound() 1379 ? CTAK_DeducedFromArrayBound 1380 : CTAK_Deduced)) { 1381 Info.Param = makeTemplateParameter( 1382 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1383 return TDK_SubstitutionFailure; 1384 } 1385 1386 continue; 1387 } 1388 1389 // Substitute into the default template argument, if available. 1390 TemplateArgumentLoc DefArg 1391 = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate, 1392 FunctionTemplate->getLocation(), 1393 FunctionTemplate->getSourceRange().getEnd(), 1394 Param, 1395 Builder); 1396 1397 // If there was no default argument, deduction is incomplete. 1398 if (DefArg.getArgument().isNull()) { 1399 Info.Param = makeTemplateParameter( 1400 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1401 return TDK_Incomplete; 1402 } 1403 1404 // Check whether we can actually use the default argument. 1405 if (CheckTemplateArgument(Param, DefArg, 1406 FunctionTemplate, 1407 FunctionTemplate->getLocation(), 1408 FunctionTemplate->getSourceRange().getEnd(), 1409 Builder, 1410 CTAK_Deduced)) { 1411 Info.Param = makeTemplateParameter( 1412 const_cast<NamedDecl *>(TemplateParams->getParam(I))); 1413 return TDK_SubstitutionFailure; 1414 } 1415 1416 // If we get here, we successfully used the default template argument. 1417 } 1418 1419 // Form the template argument list from the deduced template arguments. 1420 TemplateArgumentList *DeducedArgumentList 1421 = new (Context) TemplateArgumentList(Context, Builder, /*TakeArgs=*/true); 1422 Info.reset(DeducedArgumentList); 1423 1424 // Substitute the deduced template arguments into the function template 1425 // declaration to produce the function template specialization. 1426 DeclContext *Owner = FunctionTemplate->getDeclContext(); 1427 if (FunctionTemplate->getFriendObjectKind()) 1428 Owner = FunctionTemplate->getLexicalDeclContext(); 1429 Specialization = cast_or_null<FunctionDecl>( 1430 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner, 1431 MultiLevelTemplateArgumentList(*DeducedArgumentList))); 1432 if (!Specialization) 1433 return TDK_SubstitutionFailure; 1434 1435 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() == 1436 FunctionTemplate->getCanonicalDecl()); 1437 1438 // If the template argument list is owned by the function template 1439 // specialization, release it. 1440 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList) 1441 Info.take(); 1442 1443 // There may have been an error that did not prevent us from constructing a 1444 // declaration. Mark the declaration invalid and return with a substitution 1445 // failure. 1446 if (Trap.hasErrorOccurred()) { 1447 Specialization->setInvalidDecl(true); 1448 return TDK_SubstitutionFailure; 1449 } 1450 1451 return TDK_Success; 1452} 1453 1454static QualType GetTypeOfFunction(ASTContext &Context, 1455 bool isAddressOfOperand, 1456 FunctionDecl *Fn) { 1457 if (!isAddressOfOperand) return Fn->getType(); 1458 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) 1459 if (Method->isInstance()) 1460 return Context.getMemberPointerType(Fn->getType(), 1461 Context.getTypeDeclType(Method->getParent()).getTypePtr()); 1462 return Context.getPointerType(Fn->getType()); 1463} 1464 1465/// Apply the deduction rules for overload sets. 1466/// 1467/// \return the null type if this argument should be treated as an 1468/// undeduced context 1469static QualType 1470ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams, 1471 Expr *Arg, QualType ParamType) { 1472 llvm::PointerIntPair<OverloadExpr*,1> R = OverloadExpr::find(Arg); 1473 1474 bool isAddressOfOperand = bool(R.getInt()); 1475 OverloadExpr *Ovl = R.getPointer(); 1476 1477 // If there were explicit template arguments, we can only find 1478 // something via C++ [temp.arg.explicit]p3, i.e. if the arguments 1479 // unambiguously name a full specialization. 1480 if (Ovl->hasExplicitTemplateArgs()) { 1481 // But we can still look for an explicit specialization. 1482 if (FunctionDecl *ExplicitSpec 1483 = S.ResolveSingleFunctionTemplateSpecialization(Ovl)) 1484 return GetTypeOfFunction(S.Context, isAddressOfOperand, ExplicitSpec); 1485 return QualType(); 1486 } 1487 1488 // C++0x [temp.deduct.call]p6: 1489 // When P is a function type, pointer to function type, or pointer 1490 // to member function type: 1491 1492 if (!ParamType->isFunctionType() && 1493 !ParamType->isFunctionPointerType() && 1494 !ParamType->isMemberFunctionPointerType()) 1495 return QualType(); 1496 1497 QualType Match; 1498 for (UnresolvedSetIterator I = Ovl->decls_begin(), 1499 E = Ovl->decls_end(); I != E; ++I) { 1500 NamedDecl *D = (*I)->getUnderlyingDecl(); 1501 1502 // - If the argument is an overload set containing one or more 1503 // function templates, the parameter is treated as a 1504 // non-deduced context. 1505 if (isa<FunctionTemplateDecl>(D)) 1506 return QualType(); 1507 1508 FunctionDecl *Fn = cast<FunctionDecl>(D); 1509 QualType ArgType = GetTypeOfFunction(S.Context, isAddressOfOperand, Fn); 1510 1511 // - If the argument is an overload set (not containing function 1512 // templates), trial argument deduction is attempted using each 1513 // of the members of the set. If deduction succeeds for only one 1514 // of the overload set members, that member is used as the 1515 // argument value for the deduction. If deduction succeeds for 1516 // more than one member of the overload set the parameter is 1517 // treated as a non-deduced context. 1518 1519 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2: 1520 // Type deduction is done independently for each P/A pair, and 1521 // the deduced template argument values are then combined. 1522 // So we do not reject deductions which were made elsewhere. 1523 llvm::SmallVector<DeducedTemplateArgument, 8> 1524 Deduced(TemplateParams->size()); 1525 Sema::TemplateDeductionInfo Info(S.Context, Ovl->getNameLoc()); 1526 unsigned TDF = 0; 1527 1528 Sema::TemplateDeductionResult Result 1529 = DeduceTemplateArguments(S, TemplateParams, 1530 ParamType, ArgType, 1531 Info, Deduced, TDF); 1532 if (Result) continue; 1533 if (!Match.isNull()) return QualType(); 1534 Match = ArgType; 1535 } 1536 1537 return Match; 1538} 1539 1540/// \brief Perform template argument deduction from a function call 1541/// (C++ [temp.deduct.call]). 1542/// 1543/// \param FunctionTemplate the function template for which we are performing 1544/// template argument deduction. 1545/// 1546/// \param ExplicitTemplateArguments the explicit template arguments provided 1547/// for this call. 1548/// 1549/// \param Args the function call arguments 1550/// 1551/// \param NumArgs the number of arguments in Args 1552/// 1553/// \param Name the name of the function being called. This is only significant 1554/// when the function template is a conversion function template, in which 1555/// case this routine will also perform template argument deduction based on 1556/// the function to which 1557/// 1558/// \param Specialization if template argument deduction was successful, 1559/// this will be set to the function template specialization produced by 1560/// template argument deduction. 1561/// 1562/// \param Info the argument will be updated to provide additional information 1563/// about template argument deduction. 1564/// 1565/// \returns the result of template argument deduction. 1566Sema::TemplateDeductionResult 1567Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1568 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1569 Expr **Args, unsigned NumArgs, 1570 FunctionDecl *&Specialization, 1571 TemplateDeductionInfo &Info) { 1572 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1573 1574 // C++ [temp.deduct.call]p1: 1575 // Template argument deduction is done by comparing each function template 1576 // parameter type (call it P) with the type of the corresponding argument 1577 // of the call (call it A) as described below. 1578 unsigned CheckArgs = NumArgs; 1579 if (NumArgs < Function->getMinRequiredArguments()) 1580 return TDK_TooFewArguments; 1581 else if (NumArgs > Function->getNumParams()) { 1582 const FunctionProtoType *Proto 1583 = Function->getType()->getAs<FunctionProtoType>(); 1584 if (!Proto->isVariadic()) 1585 return TDK_TooManyArguments; 1586 1587 CheckArgs = Function->getNumParams(); 1588 } 1589 1590 // The types of the parameters from which we will perform template argument 1591 // deduction. 1592 Sema::LocalInstantiationScope InstScope(*this); 1593 TemplateParameterList *TemplateParams 1594 = FunctionTemplate->getTemplateParameters(); 1595 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1596 llvm::SmallVector<QualType, 4> ParamTypes; 1597 unsigned NumExplicitlySpecified = 0; 1598 if (ExplicitTemplateArgs) { 1599 TemplateDeductionResult Result = 1600 SubstituteExplicitTemplateArguments(FunctionTemplate, 1601 *ExplicitTemplateArgs, 1602 Deduced, 1603 ParamTypes, 1604 0, 1605 Info); 1606 if (Result) 1607 return Result; 1608 1609 NumExplicitlySpecified = Deduced.size(); 1610 } else { 1611 // Just fill in the parameter types from the function declaration. 1612 for (unsigned I = 0; I != CheckArgs; ++I) 1613 ParamTypes.push_back(Function->getParamDecl(I)->getType()); 1614 } 1615 1616 // Deduce template arguments from the function parameters. 1617 Deduced.resize(TemplateParams->size()); 1618 for (unsigned I = 0; I != CheckArgs; ++I) { 1619 QualType ParamType = ParamTypes[I]; 1620 QualType ArgType = Args[I]->getType(); 1621 1622 // Overload sets usually make this parameter an undeduced 1623 // context, but there are sometimes special circumstances. 1624 if (ArgType == Context.OverloadTy) { 1625 ArgType = ResolveOverloadForDeduction(*this, TemplateParams, 1626 Args[I], ParamType); 1627 if (ArgType.isNull()) 1628 continue; 1629 } 1630 1631 // C++ [temp.deduct.call]p2: 1632 // If P is not a reference type: 1633 QualType CanonParamType = Context.getCanonicalType(ParamType); 1634 bool ParamWasReference = isa<ReferenceType>(CanonParamType); 1635 if (!ParamWasReference) { 1636 // - If A is an array type, the pointer type produced by the 1637 // array-to-pointer standard conversion (4.2) is used in place of 1638 // A for type deduction; otherwise, 1639 if (ArgType->isArrayType()) 1640 ArgType = Context.getArrayDecayedType(ArgType); 1641 // - If A is a function type, the pointer type produced by the 1642 // function-to-pointer standard conversion (4.3) is used in place 1643 // of A for type deduction; otherwise, 1644 else if (ArgType->isFunctionType()) 1645 ArgType = Context.getPointerType(ArgType); 1646 else { 1647 // - If A is a cv-qualified type, the top level cv-qualifiers of A’s 1648 // type are ignored for type deduction. 1649 QualType CanonArgType = Context.getCanonicalType(ArgType); 1650 if (CanonArgType.getLocalCVRQualifiers()) 1651 ArgType = CanonArgType.getLocalUnqualifiedType(); 1652 } 1653 } 1654 1655 // C++0x [temp.deduct.call]p3: 1656 // If P is a cv-qualified type, the top level cv-qualifiers of P’s type 1657 // are ignored for type deduction. 1658 if (CanonParamType.getLocalCVRQualifiers()) 1659 ParamType = CanonParamType.getLocalUnqualifiedType(); 1660 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) { 1661 // [...] If P is a reference type, the type referred to by P is used 1662 // for type deduction. 1663 ParamType = ParamRefType->getPointeeType(); 1664 1665 // [...] If P is of the form T&&, where T is a template parameter, and 1666 // the argument is an lvalue, the type A& is used in place of A for 1667 // type deduction. 1668 if (isa<RValueReferenceType>(ParamRefType) && 1669 ParamRefType->getAs<TemplateTypeParmType>() && 1670 Args[I]->isLvalue(Context) == Expr::LV_Valid) 1671 ArgType = Context.getLValueReferenceType(ArgType); 1672 } 1673 1674 // C++0x [temp.deduct.call]p4: 1675 // In general, the deduction process attempts to find template argument 1676 // values that will make the deduced A identical to A (after the type A 1677 // is transformed as described above). [...] 1678 unsigned TDF = TDF_SkipNonDependent; 1679 1680 // - If the original P is a reference type, the deduced A (i.e., the 1681 // type referred to by the reference) can be more cv-qualified than 1682 // the transformed A. 1683 if (ParamWasReference) 1684 TDF |= TDF_ParamWithReferenceType; 1685 // - The transformed A can be another pointer or pointer to member 1686 // type that can be converted to the deduced A via a qualification 1687 // conversion (4.4). 1688 if (ArgType->isPointerType() || ArgType->isMemberPointerType()) 1689 TDF |= TDF_IgnoreQualifiers; 1690 // - If P is a class and P has the form simple-template-id, then the 1691 // transformed A can be a derived class of the deduced A. Likewise, 1692 // if P is a pointer to a class of the form simple-template-id, the 1693 // transformed A can be a pointer to a derived class pointed to by 1694 // the deduced A. 1695 if (isSimpleTemplateIdType(ParamType) || 1696 (isa<PointerType>(ParamType) && 1697 isSimpleTemplateIdType( 1698 ParamType->getAs<PointerType>()->getPointeeType()))) 1699 TDF |= TDF_DerivedClass; 1700 1701 if (TemplateDeductionResult Result 1702 = ::DeduceTemplateArguments(*this, TemplateParams, 1703 ParamType, ArgType, Info, Deduced, 1704 TDF)) 1705 return Result; 1706 1707 // FIXME: we need to check that the deduced A is the same as A, 1708 // modulo the various allowed differences. 1709 } 1710 1711 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 1712 NumExplicitlySpecified, 1713 Specialization, Info); 1714} 1715 1716/// \brief Deduce template arguments when taking the address of a function 1717/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to 1718/// a template. 1719/// 1720/// \param FunctionTemplate the function template for which we are performing 1721/// template argument deduction. 1722/// 1723/// \param ExplicitTemplateArguments the explicitly-specified template 1724/// arguments. 1725/// 1726/// \param ArgFunctionType the function type that will be used as the 1727/// "argument" type (A) when performing template argument deduction from the 1728/// function template's function type. This type may be NULL, if there is no 1729/// argument type to compare against, in C++0x [temp.arg.explicit]p3. 1730/// 1731/// \param Specialization if template argument deduction was successful, 1732/// this will be set to the function template specialization produced by 1733/// template argument deduction. 1734/// 1735/// \param Info the argument will be updated to provide additional information 1736/// about template argument deduction. 1737/// 1738/// \returns the result of template argument deduction. 1739Sema::TemplateDeductionResult 1740Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1741 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1742 QualType ArgFunctionType, 1743 FunctionDecl *&Specialization, 1744 TemplateDeductionInfo &Info) { 1745 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 1746 TemplateParameterList *TemplateParams 1747 = FunctionTemplate->getTemplateParameters(); 1748 QualType FunctionType = Function->getType(); 1749 1750 // Substitute any explicit template arguments. 1751 Sema::LocalInstantiationScope InstScope(*this); 1752 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1753 unsigned NumExplicitlySpecified = 0; 1754 llvm::SmallVector<QualType, 4> ParamTypes; 1755 if (ExplicitTemplateArgs) { 1756 if (TemplateDeductionResult Result 1757 = SubstituteExplicitTemplateArguments(FunctionTemplate, 1758 *ExplicitTemplateArgs, 1759 Deduced, ParamTypes, 1760 &FunctionType, Info)) 1761 return Result; 1762 1763 NumExplicitlySpecified = Deduced.size(); 1764 } 1765 1766 // Template argument deduction for function templates in a SFINAE context. 1767 // Trap any errors that might occur. 1768 SFINAETrap Trap(*this); 1769 1770 Deduced.resize(TemplateParams->size()); 1771 1772 if (!ArgFunctionType.isNull()) { 1773 // Deduce template arguments from the function type. 1774 if (TemplateDeductionResult Result 1775 = ::DeduceTemplateArguments(*this, TemplateParams, 1776 FunctionType, ArgFunctionType, Info, 1777 Deduced, 0)) 1778 return Result; 1779 } 1780 1781 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 1782 NumExplicitlySpecified, 1783 Specialization, Info); 1784} 1785 1786/// \brief Deduce template arguments for a templated conversion 1787/// function (C++ [temp.deduct.conv]) and, if successful, produce a 1788/// conversion function template specialization. 1789Sema::TemplateDeductionResult 1790Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1791 QualType ToType, 1792 CXXConversionDecl *&Specialization, 1793 TemplateDeductionInfo &Info) { 1794 CXXConversionDecl *Conv 1795 = cast<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()); 1796 QualType FromType = Conv->getConversionType(); 1797 1798 // Canonicalize the types for deduction. 1799 QualType P = Context.getCanonicalType(FromType); 1800 QualType A = Context.getCanonicalType(ToType); 1801 1802 // C++0x [temp.deduct.conv]p3: 1803 // If P is a reference type, the type referred to by P is used for 1804 // type deduction. 1805 if (const ReferenceType *PRef = P->getAs<ReferenceType>()) 1806 P = PRef->getPointeeType(); 1807 1808 // C++0x [temp.deduct.conv]p3: 1809 // If A is a reference type, the type referred to by A is used 1810 // for type deduction. 1811 if (const ReferenceType *ARef = A->getAs<ReferenceType>()) 1812 A = ARef->getPointeeType(); 1813 // C++ [temp.deduct.conv]p2: 1814 // 1815 // If A is not a reference type: 1816 else { 1817 assert(!A->isReferenceType() && "Reference types were handled above"); 1818 1819 // - If P is an array type, the pointer type produced by the 1820 // array-to-pointer standard conversion (4.2) is used in place 1821 // of P for type deduction; otherwise, 1822 if (P->isArrayType()) 1823 P = Context.getArrayDecayedType(P); 1824 // - If P is a function type, the pointer type produced by the 1825 // function-to-pointer standard conversion (4.3) is used in 1826 // place of P for type deduction; otherwise, 1827 else if (P->isFunctionType()) 1828 P = Context.getPointerType(P); 1829 // - If P is a cv-qualified type, the top level cv-qualifiers of 1830 // P’s type are ignored for type deduction. 1831 else 1832 P = P.getUnqualifiedType(); 1833 1834 // C++0x [temp.deduct.conv]p3: 1835 // If A is a cv-qualified type, the top level cv-qualifiers of A’s 1836 // type are ignored for type deduction. 1837 A = A.getUnqualifiedType(); 1838 } 1839 1840 // Template argument deduction for function templates in a SFINAE context. 1841 // Trap any errors that might occur. 1842 SFINAETrap Trap(*this); 1843 1844 // C++ [temp.deduct.conv]p1: 1845 // Template argument deduction is done by comparing the return 1846 // type of the template conversion function (call it P) with the 1847 // type that is required as the result of the conversion (call it 1848 // A) as described in 14.8.2.4. 1849 TemplateParameterList *TemplateParams 1850 = FunctionTemplate->getTemplateParameters(); 1851 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 1852 Deduced.resize(TemplateParams->size()); 1853 1854 // C++0x [temp.deduct.conv]p4: 1855 // In general, the deduction process attempts to find template 1856 // argument values that will make the deduced A identical to 1857 // A. However, there are two cases that allow a difference: 1858 unsigned TDF = 0; 1859 // - If the original A is a reference type, A can be more 1860 // cv-qualified than the deduced A (i.e., the type referred to 1861 // by the reference) 1862 if (ToType->isReferenceType()) 1863 TDF |= TDF_ParamWithReferenceType; 1864 // - The deduced A can be another pointer or pointer to member 1865 // type that can be converted to A via a qualification 1866 // conversion. 1867 // 1868 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when 1869 // both P and A are pointers or member pointers. In this case, we 1870 // just ignore cv-qualifiers completely). 1871 if ((P->isPointerType() && A->isPointerType()) || 1872 (P->isMemberPointerType() && P->isMemberPointerType())) 1873 TDF |= TDF_IgnoreQualifiers; 1874 if (TemplateDeductionResult Result 1875 = ::DeduceTemplateArguments(*this, TemplateParams, 1876 P, A, Info, Deduced, TDF)) 1877 return Result; 1878 1879 // FIXME: we need to check that the deduced A is the same as A, 1880 // modulo the various allowed differences. 1881 1882 // Finish template argument deduction. 1883 Sema::LocalInstantiationScope InstScope(*this); 1884 FunctionDecl *Spec = 0; 1885 TemplateDeductionResult Result 1886 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced, 0, Spec, 1887 Info); 1888 Specialization = cast_or_null<CXXConversionDecl>(Spec); 1889 return Result; 1890} 1891 1892/// \brief Deduce template arguments for a function template when there is 1893/// nothing to deduce against (C++0x [temp.arg.explicit]p3). 1894/// 1895/// \param FunctionTemplate the function template for which we are performing 1896/// template argument deduction. 1897/// 1898/// \param ExplicitTemplateArguments the explicitly-specified template 1899/// arguments. 1900/// 1901/// \param Specialization if template argument deduction was successful, 1902/// this will be set to the function template specialization produced by 1903/// template argument deduction. 1904/// 1905/// \param Info the argument will be updated to provide additional information 1906/// about template argument deduction. 1907/// 1908/// \returns the result of template argument deduction. 1909Sema::TemplateDeductionResult 1910Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate, 1911 const TemplateArgumentListInfo *ExplicitTemplateArgs, 1912 FunctionDecl *&Specialization, 1913 TemplateDeductionInfo &Info) { 1914 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 1915 QualType(), Specialization, Info); 1916} 1917 1918/// \brief Stores the result of comparing the qualifiers of two types. 1919enum DeductionQualifierComparison { 1920 NeitherMoreQualified = 0, 1921 ParamMoreQualified, 1922 ArgMoreQualified 1923}; 1924 1925/// \brief Deduce the template arguments during partial ordering by comparing 1926/// the parameter type and the argument type (C++0x [temp.deduct.partial]). 1927/// 1928/// \param S the semantic analysis object within which we are deducing 1929/// 1930/// \param TemplateParams the template parameters that we are deducing 1931/// 1932/// \param ParamIn the parameter type 1933/// 1934/// \param ArgIn the argument type 1935/// 1936/// \param Info information about the template argument deduction itself 1937/// 1938/// \param Deduced the deduced template arguments 1939/// 1940/// \returns the result of template argument deduction so far. Note that a 1941/// "success" result means that template argument deduction has not yet failed, 1942/// but it may still fail, later, for other reasons. 1943static Sema::TemplateDeductionResult 1944DeduceTemplateArgumentsDuringPartialOrdering(Sema &S, 1945 TemplateParameterList *TemplateParams, 1946 QualType ParamIn, QualType ArgIn, 1947 Sema::TemplateDeductionInfo &Info, 1948 llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced, 1949 llvm::SmallVectorImpl<DeductionQualifierComparison> *QualifierComparisons) { 1950 CanQualType Param = S.Context.getCanonicalType(ParamIn); 1951 CanQualType Arg = S.Context.getCanonicalType(ArgIn); 1952 1953 // C++0x [temp.deduct.partial]p5: 1954 // Before the partial ordering is done, certain transformations are 1955 // performed on the types used for partial ordering: 1956 // - If P is a reference type, P is replaced by the type referred to. 1957 CanQual<ReferenceType> ParamRef = Param->getAs<ReferenceType>(); 1958 if (!ParamRef.isNull()) 1959 Param = ParamRef->getPointeeType(); 1960 1961 // - If A is a reference type, A is replaced by the type referred to. 1962 CanQual<ReferenceType> ArgRef = Arg->getAs<ReferenceType>(); 1963 if (!ArgRef.isNull()) 1964 Arg = ArgRef->getPointeeType(); 1965 1966 if (QualifierComparisons && !ParamRef.isNull() && !ArgRef.isNull()) { 1967 // C++0x [temp.deduct.partial]p6: 1968 // If both P and A were reference types (before being replaced with the 1969 // type referred to above), determine which of the two types (if any) is 1970 // more cv-qualified than the other; otherwise the types are considered to 1971 // be equally cv-qualified for partial ordering purposes. The result of this 1972 // determination will be used below. 1973 // 1974 // We save this information for later, using it only when deduction 1975 // succeeds in both directions. 1976 DeductionQualifierComparison QualifierResult = NeitherMoreQualified; 1977 if (Param.isMoreQualifiedThan(Arg)) 1978 QualifierResult = ParamMoreQualified; 1979 else if (Arg.isMoreQualifiedThan(Param)) 1980 QualifierResult = ArgMoreQualified; 1981 QualifierComparisons->push_back(QualifierResult); 1982 } 1983 1984 // C++0x [temp.deduct.partial]p7: 1985 // Remove any top-level cv-qualifiers: 1986 // - If P is a cv-qualified type, P is replaced by the cv-unqualified 1987 // version of P. 1988 Param = Param.getUnqualifiedType(); 1989 // - If A is a cv-qualified type, A is replaced by the cv-unqualified 1990 // version of A. 1991 Arg = Arg.getUnqualifiedType(); 1992 1993 // C++0x [temp.deduct.partial]p8: 1994 // Using the resulting types P and A the deduction is then done as 1995 // described in 14.9.2.5. If deduction succeeds for a given type, the type 1996 // from the argument template is considered to be at least as specialized 1997 // as the type from the parameter template. 1998 return DeduceTemplateArguments(S, TemplateParams, Param, Arg, Info, 1999 Deduced, TDF_None); 2000} 2001 2002static void 2003MarkUsedTemplateParameters(Sema &SemaRef, QualType T, 2004 bool OnlyDeduced, 2005 unsigned Level, 2006 llvm::SmallVectorImpl<bool> &Deduced); 2007 2008/// \brief Determine whether the function template \p FT1 is at least as 2009/// specialized as \p FT2. 2010static bool isAtLeastAsSpecializedAs(Sema &S, 2011 SourceLocation Loc, 2012 FunctionTemplateDecl *FT1, 2013 FunctionTemplateDecl *FT2, 2014 TemplatePartialOrderingContext TPOC, 2015 llvm::SmallVectorImpl<DeductionQualifierComparison> *QualifierComparisons) { 2016 FunctionDecl *FD1 = FT1->getTemplatedDecl(); 2017 FunctionDecl *FD2 = FT2->getTemplatedDecl(); 2018 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>(); 2019 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>(); 2020 2021 assert(Proto1 && Proto2 && "Function templates must have prototypes"); 2022 TemplateParameterList *TemplateParams = FT2->getTemplateParameters(); 2023 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 2024 Deduced.resize(TemplateParams->size()); 2025 2026 // C++0x [temp.deduct.partial]p3: 2027 // The types used to determine the ordering depend on the context in which 2028 // the partial ordering is done: 2029 Sema::TemplateDeductionInfo Info(S.Context, Loc); 2030 switch (TPOC) { 2031 case TPOC_Call: { 2032 // - In the context of a function call, the function parameter types are 2033 // used. 2034 unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); 2035 for (unsigned I = 0; I != NumParams; ++I) 2036 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2037 TemplateParams, 2038 Proto2->getArgType(I), 2039 Proto1->getArgType(I), 2040 Info, 2041 Deduced, 2042 QualifierComparisons)) 2043 return false; 2044 2045 break; 2046 } 2047 2048 case TPOC_Conversion: 2049 // - In the context of a call to a conversion operator, the return types 2050 // of the conversion function templates are used. 2051 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2052 TemplateParams, 2053 Proto2->getResultType(), 2054 Proto1->getResultType(), 2055 Info, 2056 Deduced, 2057 QualifierComparisons)) 2058 return false; 2059 break; 2060 2061 case TPOC_Other: 2062 // - In other contexts (14.6.6.2) the function template’s function type 2063 // is used. 2064 if (DeduceTemplateArgumentsDuringPartialOrdering(S, 2065 TemplateParams, 2066 FD2->getType(), 2067 FD1->getType(), 2068 Info, 2069 Deduced, 2070 QualifierComparisons)) 2071 return false; 2072 break; 2073 } 2074 2075 // C++0x [temp.deduct.partial]p11: 2076 // In most cases, all template parameters must have values in order for 2077 // deduction to succeed, but for partial ordering purposes a template 2078 // parameter may remain without a value provided it is not used in the 2079 // types being used for partial ordering. [ Note: a template parameter used 2080 // in a non-deduced context is considered used. -end note] 2081 unsigned ArgIdx = 0, NumArgs = Deduced.size(); 2082 for (; ArgIdx != NumArgs; ++ArgIdx) 2083 if (Deduced[ArgIdx].isNull()) 2084 break; 2085 2086 if (ArgIdx == NumArgs) { 2087 // All template arguments were deduced. FT1 is at least as specialized 2088 // as FT2. 2089 return true; 2090 } 2091 2092 // Figure out which template parameters were used. 2093 llvm::SmallVector<bool, 4> UsedParameters; 2094 UsedParameters.resize(TemplateParams->size()); 2095 switch (TPOC) { 2096 case TPOC_Call: { 2097 unsigned NumParams = std::min(Proto1->getNumArgs(), Proto2->getNumArgs()); 2098 for (unsigned I = 0; I != NumParams; ++I) 2099 ::MarkUsedTemplateParameters(S, Proto2->getArgType(I), false, 2100 TemplateParams->getDepth(), 2101 UsedParameters); 2102 break; 2103 } 2104 2105 case TPOC_Conversion: 2106 ::MarkUsedTemplateParameters(S, Proto2->getResultType(), false, 2107 TemplateParams->getDepth(), 2108 UsedParameters); 2109 break; 2110 2111 case TPOC_Other: 2112 ::MarkUsedTemplateParameters(S, FD2->getType(), false, 2113 TemplateParams->getDepth(), 2114 UsedParameters); 2115 break; 2116 } 2117 2118 for (; ArgIdx != NumArgs; ++ArgIdx) 2119 // If this argument had no value deduced but was used in one of the types 2120 // used for partial ordering, then deduction fails. 2121 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx]) 2122 return false; 2123 2124 return true; 2125} 2126 2127 2128/// \brief Returns the more specialized function template according 2129/// to the rules of function template partial ordering (C++ [temp.func.order]). 2130/// 2131/// \param FT1 the first function template 2132/// 2133/// \param FT2 the second function template 2134/// 2135/// \param TPOC the context in which we are performing partial ordering of 2136/// function templates. 2137/// 2138/// \returns the more specialized function template. If neither 2139/// template is more specialized, returns NULL. 2140FunctionTemplateDecl * 2141Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1, 2142 FunctionTemplateDecl *FT2, 2143 SourceLocation Loc, 2144 TemplatePartialOrderingContext TPOC) { 2145 llvm::SmallVector<DeductionQualifierComparison, 4> QualifierComparisons; 2146 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC, 0); 2147 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC, 2148 &QualifierComparisons); 2149 2150 if (Better1 != Better2) // We have a clear winner 2151 return Better1? FT1 : FT2; 2152 2153 if (!Better1 && !Better2) // Neither is better than the other 2154 return 0; 2155 2156 2157 // C++0x [temp.deduct.partial]p10: 2158 // If for each type being considered a given template is at least as 2159 // specialized for all types and more specialized for some set of types and 2160 // the other template is not more specialized for any types or is not at 2161 // least as specialized for any types, then the given template is more 2162 // specialized than the other template. Otherwise, neither template is more 2163 // specialized than the other. 2164 Better1 = false; 2165 Better2 = false; 2166 for (unsigned I = 0, N = QualifierComparisons.size(); I != N; ++I) { 2167 // C++0x [temp.deduct.partial]p9: 2168 // If, for a given type, deduction succeeds in both directions (i.e., the 2169 // types are identical after the transformations above) and if the type 2170 // from the argument template is more cv-qualified than the type from the 2171 // parameter template (as described above) that type is considered to be 2172 // more specialized than the other. If neither type is more cv-qualified 2173 // than the other then neither type is more specialized than the other. 2174 switch (QualifierComparisons[I]) { 2175 case NeitherMoreQualified: 2176 break; 2177 2178 case ParamMoreQualified: 2179 Better1 = true; 2180 if (Better2) 2181 return 0; 2182 break; 2183 2184 case ArgMoreQualified: 2185 Better2 = true; 2186 if (Better1) 2187 return 0; 2188 break; 2189 } 2190 } 2191 2192 assert(!(Better1 && Better2) && "Should have broken out in the loop above"); 2193 if (Better1) 2194 return FT1; 2195 else if (Better2) 2196 return FT2; 2197 else 2198 return 0; 2199} 2200 2201/// \brief Determine if the two templates are equivalent. 2202static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) { 2203 if (T1 == T2) 2204 return true; 2205 2206 if (!T1 || !T2) 2207 return false; 2208 2209 return T1->getCanonicalDecl() == T2->getCanonicalDecl(); 2210} 2211 2212/// \brief Retrieve the most specialized of the given function template 2213/// specializations. 2214/// 2215/// \param SpecBegin the start iterator of the function template 2216/// specializations that we will be comparing. 2217/// 2218/// \param SpecEnd the end iterator of the function template 2219/// specializations, paired with \p SpecBegin. 2220/// 2221/// \param TPOC the partial ordering context to use to compare the function 2222/// template specializations. 2223/// 2224/// \param Loc the location where the ambiguity or no-specializations 2225/// diagnostic should occur. 2226/// 2227/// \param NoneDiag partial diagnostic used to diagnose cases where there are 2228/// no matching candidates. 2229/// 2230/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one 2231/// occurs. 2232/// 2233/// \param CandidateDiag partial diagnostic used for each function template 2234/// specialization that is a candidate in the ambiguous ordering. One parameter 2235/// in this diagnostic should be unbound, which will correspond to the string 2236/// describing the template arguments for the function template specialization. 2237/// 2238/// \param Index if non-NULL and the result of this function is non-nULL, 2239/// receives the index corresponding to the resulting function template 2240/// specialization. 2241/// 2242/// \returns the most specialized function template specialization, if 2243/// found. Otherwise, returns SpecEnd. 2244/// 2245/// \todo FIXME: Consider passing in the "also-ran" candidates that failed 2246/// template argument deduction. 2247UnresolvedSetIterator 2248Sema::getMostSpecialized(UnresolvedSetIterator SpecBegin, 2249 UnresolvedSetIterator SpecEnd, 2250 TemplatePartialOrderingContext TPOC, 2251 SourceLocation Loc, 2252 const PartialDiagnostic &NoneDiag, 2253 const PartialDiagnostic &AmbigDiag, 2254 const PartialDiagnostic &CandidateDiag) { 2255 if (SpecBegin == SpecEnd) { 2256 Diag(Loc, NoneDiag); 2257 return SpecEnd; 2258 } 2259 2260 if (SpecBegin + 1 == SpecEnd) 2261 return SpecBegin; 2262 2263 // Find the function template that is better than all of the templates it 2264 // has been compared to. 2265 UnresolvedSetIterator Best = SpecBegin; 2266 FunctionTemplateDecl *BestTemplate 2267 = cast<FunctionDecl>(*Best)->getPrimaryTemplate(); 2268 assert(BestTemplate && "Not a function template specialization?"); 2269 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) { 2270 FunctionTemplateDecl *Challenger 2271 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 2272 assert(Challenger && "Not a function template specialization?"); 2273 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 2274 Loc, TPOC), 2275 Challenger)) { 2276 Best = I; 2277 BestTemplate = Challenger; 2278 } 2279 } 2280 2281 // Make sure that the "best" function template is more specialized than all 2282 // of the others. 2283 bool Ambiguous = false; 2284 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) { 2285 FunctionTemplateDecl *Challenger 2286 = cast<FunctionDecl>(*I)->getPrimaryTemplate(); 2287 if (I != Best && 2288 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger, 2289 Loc, TPOC), 2290 BestTemplate)) { 2291 Ambiguous = true; 2292 break; 2293 } 2294 } 2295 2296 if (!Ambiguous) { 2297 // We found an answer. Return it. 2298 return Best; 2299 } 2300 2301 // Diagnose the ambiguity. 2302 Diag(Loc, AmbigDiag); 2303 2304 // FIXME: Can we order the candidates in some sane way? 2305 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) 2306 Diag((*I)->getLocation(), CandidateDiag) 2307 << getTemplateArgumentBindingsText( 2308 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(), 2309 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs()); 2310 2311 return SpecEnd; 2312} 2313 2314/// \brief Returns the more specialized class template partial specialization 2315/// according to the rules of partial ordering of class template partial 2316/// specializations (C++ [temp.class.order]). 2317/// 2318/// \param PS1 the first class template partial specialization 2319/// 2320/// \param PS2 the second class template partial specialization 2321/// 2322/// \returns the more specialized class template partial specialization. If 2323/// neither partial specialization is more specialized, returns NULL. 2324ClassTemplatePartialSpecializationDecl * 2325Sema::getMoreSpecializedPartialSpecialization( 2326 ClassTemplatePartialSpecializationDecl *PS1, 2327 ClassTemplatePartialSpecializationDecl *PS2, 2328 SourceLocation Loc) { 2329 // C++ [temp.class.order]p1: 2330 // For two class template partial specializations, the first is at least as 2331 // specialized as the second if, given the following rewrite to two 2332 // function templates, the first function template is at least as 2333 // specialized as the second according to the ordering rules for function 2334 // templates (14.6.6.2): 2335 // - the first function template has the same template parameters as the 2336 // first partial specialization and has a single function parameter 2337 // whose type is a class template specialization with the template 2338 // arguments of the first partial specialization, and 2339 // - the second function template has the same template parameters as the 2340 // second partial specialization and has a single function parameter 2341 // whose type is a class template specialization with the template 2342 // arguments of the second partial specialization. 2343 // 2344 // Rather than synthesize function templates, we merely perform the 2345 // equivalent partial ordering by performing deduction directly on the 2346 // template arguments of the class template partial specializations. This 2347 // computation is slightly simpler than the general problem of function 2348 // template partial ordering, because class template partial specializations 2349 // are more constrained. We know that every template parameter is deduc 2350 llvm::SmallVector<DeducedTemplateArgument, 4> Deduced; 2351 Sema::TemplateDeductionInfo Info(Context, Loc); 2352 2353 QualType PT1 = PS1->getInjectedSpecializationType(); 2354 QualType PT2 = PS2->getInjectedSpecializationType(); 2355 2356 // Determine whether PS1 is at least as specialized as PS2 2357 Deduced.resize(PS2->getTemplateParameters()->size()); 2358 bool Better1 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, 2359 PS2->getTemplateParameters(), 2360 PT2, 2361 PT1, 2362 Info, 2363 Deduced, 2364 0); 2365 2366 // Determine whether PS2 is at least as specialized as PS1 2367 Deduced.clear(); 2368 Deduced.resize(PS1->getTemplateParameters()->size()); 2369 bool Better2 = !DeduceTemplateArgumentsDuringPartialOrdering(*this, 2370 PS1->getTemplateParameters(), 2371 PT1, 2372 PT2, 2373 Info, 2374 Deduced, 2375 0); 2376 2377 if (Better1 == Better2) 2378 return 0; 2379 2380 return Better1? PS1 : PS2; 2381} 2382 2383static void 2384MarkUsedTemplateParameters(Sema &SemaRef, 2385 const TemplateArgument &TemplateArg, 2386 bool OnlyDeduced, 2387 unsigned Depth, 2388 llvm::SmallVectorImpl<bool> &Used); 2389 2390/// \brief Mark the template parameters that are used by the given 2391/// expression. 2392static void 2393MarkUsedTemplateParameters(Sema &SemaRef, 2394 const Expr *E, 2395 bool OnlyDeduced, 2396 unsigned Depth, 2397 llvm::SmallVectorImpl<bool> &Used) { 2398 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to 2399 // find other occurrences of template parameters. 2400 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E); 2401 if (!DRE) 2402 return; 2403 2404 const NonTypeTemplateParmDecl *NTTP 2405 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl()); 2406 if (!NTTP) 2407 return; 2408 2409 if (NTTP->getDepth() == Depth) 2410 Used[NTTP->getIndex()] = true; 2411} 2412 2413/// \brief Mark the template parameters that are used by the given 2414/// nested name specifier. 2415static void 2416MarkUsedTemplateParameters(Sema &SemaRef, 2417 NestedNameSpecifier *NNS, 2418 bool OnlyDeduced, 2419 unsigned Depth, 2420 llvm::SmallVectorImpl<bool> &Used) { 2421 if (!NNS) 2422 return; 2423 2424 MarkUsedTemplateParameters(SemaRef, NNS->getPrefix(), OnlyDeduced, Depth, 2425 Used); 2426 MarkUsedTemplateParameters(SemaRef, QualType(NNS->getAsType(), 0), 2427 OnlyDeduced, Depth, Used); 2428} 2429 2430/// \brief Mark the template parameters that are used by the given 2431/// template name. 2432static void 2433MarkUsedTemplateParameters(Sema &SemaRef, 2434 TemplateName Name, 2435 bool OnlyDeduced, 2436 unsigned Depth, 2437 llvm::SmallVectorImpl<bool> &Used) { 2438 if (TemplateDecl *Template = Name.getAsTemplateDecl()) { 2439 if (TemplateTemplateParmDecl *TTP 2440 = dyn_cast<TemplateTemplateParmDecl>(Template)) { 2441 if (TTP->getDepth() == Depth) 2442 Used[TTP->getIndex()] = true; 2443 } 2444 return; 2445 } 2446 2447 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName()) 2448 MarkUsedTemplateParameters(SemaRef, QTN->getQualifier(), OnlyDeduced, 2449 Depth, Used); 2450 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName()) 2451 MarkUsedTemplateParameters(SemaRef, DTN->getQualifier(), OnlyDeduced, 2452 Depth, Used); 2453} 2454 2455/// \brief Mark the template parameters that are used by the given 2456/// type. 2457static void 2458MarkUsedTemplateParameters(Sema &SemaRef, QualType T, 2459 bool OnlyDeduced, 2460 unsigned Depth, 2461 llvm::SmallVectorImpl<bool> &Used) { 2462 if (T.isNull()) 2463 return; 2464 2465 // Non-dependent types have nothing deducible 2466 if (!T->isDependentType()) 2467 return; 2468 2469 T = SemaRef.Context.getCanonicalType(T); 2470 switch (T->getTypeClass()) { 2471 case Type::Pointer: 2472 MarkUsedTemplateParameters(SemaRef, 2473 cast<PointerType>(T)->getPointeeType(), 2474 OnlyDeduced, 2475 Depth, 2476 Used); 2477 break; 2478 2479 case Type::BlockPointer: 2480 MarkUsedTemplateParameters(SemaRef, 2481 cast<BlockPointerType>(T)->getPointeeType(), 2482 OnlyDeduced, 2483 Depth, 2484 Used); 2485 break; 2486 2487 case Type::LValueReference: 2488 case Type::RValueReference: 2489 MarkUsedTemplateParameters(SemaRef, 2490 cast<ReferenceType>(T)->getPointeeType(), 2491 OnlyDeduced, 2492 Depth, 2493 Used); 2494 break; 2495 2496 case Type::MemberPointer: { 2497 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr()); 2498 MarkUsedTemplateParameters(SemaRef, MemPtr->getPointeeType(), OnlyDeduced, 2499 Depth, Used); 2500 MarkUsedTemplateParameters(SemaRef, QualType(MemPtr->getClass(), 0), 2501 OnlyDeduced, Depth, Used); 2502 break; 2503 } 2504 2505 case Type::DependentSizedArray: 2506 MarkUsedTemplateParameters(SemaRef, 2507 cast<DependentSizedArrayType>(T)->getSizeExpr(), 2508 OnlyDeduced, Depth, Used); 2509 // Fall through to check the element type 2510 2511 case Type::ConstantArray: 2512 case Type::IncompleteArray: 2513 MarkUsedTemplateParameters(SemaRef, 2514 cast<ArrayType>(T)->getElementType(), 2515 OnlyDeduced, Depth, Used); 2516 break; 2517 2518 case Type::Vector: 2519 case Type::ExtVector: 2520 MarkUsedTemplateParameters(SemaRef, 2521 cast<VectorType>(T)->getElementType(), 2522 OnlyDeduced, Depth, Used); 2523 break; 2524 2525 case Type::DependentSizedExtVector: { 2526 const DependentSizedExtVectorType *VecType 2527 = cast<DependentSizedExtVectorType>(T); 2528 MarkUsedTemplateParameters(SemaRef, VecType->getElementType(), OnlyDeduced, 2529 Depth, Used); 2530 MarkUsedTemplateParameters(SemaRef, VecType->getSizeExpr(), OnlyDeduced, 2531 Depth, Used); 2532 break; 2533 } 2534 2535 case Type::FunctionProto: { 2536 const FunctionProtoType *Proto = cast<FunctionProtoType>(T); 2537 MarkUsedTemplateParameters(SemaRef, Proto->getResultType(), OnlyDeduced, 2538 Depth, Used); 2539 for (unsigned I = 0, N = Proto->getNumArgs(); I != N; ++I) 2540 MarkUsedTemplateParameters(SemaRef, Proto->getArgType(I), OnlyDeduced, 2541 Depth, Used); 2542 break; 2543 } 2544 2545 case Type::TemplateTypeParm: { 2546 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T); 2547 if (TTP->getDepth() == Depth) 2548 Used[TTP->getIndex()] = true; 2549 break; 2550 } 2551 2552 case Type::InjectedClassName: 2553 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType(); 2554 // fall through 2555 2556 case Type::TemplateSpecialization: { 2557 const TemplateSpecializationType *Spec 2558 = cast<TemplateSpecializationType>(T); 2559 MarkUsedTemplateParameters(SemaRef, Spec->getTemplateName(), OnlyDeduced, 2560 Depth, Used); 2561 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I) 2562 MarkUsedTemplateParameters(SemaRef, Spec->getArg(I), OnlyDeduced, Depth, 2563 Used); 2564 break; 2565 } 2566 2567 case Type::Complex: 2568 if (!OnlyDeduced) 2569 MarkUsedTemplateParameters(SemaRef, 2570 cast<ComplexType>(T)->getElementType(), 2571 OnlyDeduced, Depth, Used); 2572 break; 2573 2574 case Type::DependentName: 2575 if (!OnlyDeduced) 2576 MarkUsedTemplateParameters(SemaRef, 2577 cast<DependentNameType>(T)->getQualifier(), 2578 OnlyDeduced, Depth, Used); 2579 break; 2580 2581 case Type::TypeOf: 2582 if (!OnlyDeduced) 2583 MarkUsedTemplateParameters(SemaRef, 2584 cast<TypeOfType>(T)->getUnderlyingType(), 2585 OnlyDeduced, Depth, Used); 2586 break; 2587 2588 case Type::TypeOfExpr: 2589 if (!OnlyDeduced) 2590 MarkUsedTemplateParameters(SemaRef, 2591 cast<TypeOfExprType>(T)->getUnderlyingExpr(), 2592 OnlyDeduced, Depth, Used); 2593 break; 2594 2595 case Type::Decltype: 2596 if (!OnlyDeduced) 2597 MarkUsedTemplateParameters(SemaRef, 2598 cast<DecltypeType>(T)->getUnderlyingExpr(), 2599 OnlyDeduced, Depth, Used); 2600 break; 2601 2602 // None of these types have any template parameters in them. 2603 case Type::Builtin: 2604 case Type::VariableArray: 2605 case Type::FunctionNoProto: 2606 case Type::Record: 2607 case Type::Enum: 2608 case Type::ObjCInterface: 2609 case Type::ObjCObjectPointer: 2610 case Type::UnresolvedUsing: 2611#define TYPE(Class, Base) 2612#define ABSTRACT_TYPE(Class, Base) 2613#define DEPENDENT_TYPE(Class, Base) 2614#define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 2615#include "clang/AST/TypeNodes.def" 2616 break; 2617 } 2618} 2619 2620/// \brief Mark the template parameters that are used by this 2621/// template argument. 2622static void 2623MarkUsedTemplateParameters(Sema &SemaRef, 2624 const TemplateArgument &TemplateArg, 2625 bool OnlyDeduced, 2626 unsigned Depth, 2627 llvm::SmallVectorImpl<bool> &Used) { 2628 switch (TemplateArg.getKind()) { 2629 case TemplateArgument::Null: 2630 case TemplateArgument::Integral: 2631 case TemplateArgument::Declaration: 2632 break; 2633 2634 case TemplateArgument::Type: 2635 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsType(), OnlyDeduced, 2636 Depth, Used); 2637 break; 2638 2639 case TemplateArgument::Template: 2640 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsTemplate(), 2641 OnlyDeduced, Depth, Used); 2642 break; 2643 2644 case TemplateArgument::Expression: 2645 MarkUsedTemplateParameters(SemaRef, TemplateArg.getAsExpr(), OnlyDeduced, 2646 Depth, Used); 2647 break; 2648 2649 case TemplateArgument::Pack: 2650 for (TemplateArgument::pack_iterator P = TemplateArg.pack_begin(), 2651 PEnd = TemplateArg.pack_end(); 2652 P != PEnd; ++P) 2653 MarkUsedTemplateParameters(SemaRef, *P, OnlyDeduced, Depth, Used); 2654 break; 2655 } 2656} 2657 2658/// \brief Mark the template parameters can be deduced by the given 2659/// template argument list. 2660/// 2661/// \param TemplateArgs the template argument list from which template 2662/// parameters will be deduced. 2663/// 2664/// \param Deduced a bit vector whose elements will be set to \c true 2665/// to indicate when the corresponding template parameter will be 2666/// deduced. 2667void 2668Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs, 2669 bool OnlyDeduced, unsigned Depth, 2670 llvm::SmallVectorImpl<bool> &Used) { 2671 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 2672 ::MarkUsedTemplateParameters(*this, TemplateArgs[I], OnlyDeduced, 2673 Depth, Used); 2674} 2675 2676/// \brief Marks all of the template parameters that will be deduced by a 2677/// call to the given function template. 2678void 2679Sema::MarkDeducedTemplateParameters(FunctionTemplateDecl *FunctionTemplate, 2680 llvm::SmallVectorImpl<bool> &Deduced) { 2681 TemplateParameterList *TemplateParams 2682 = FunctionTemplate->getTemplateParameters(); 2683 Deduced.clear(); 2684 Deduced.resize(TemplateParams->size()); 2685 2686 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl(); 2687 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I) 2688 ::MarkUsedTemplateParameters(*this, Function->getParamDecl(I)->getType(), 2689 true, TemplateParams->getDepth(), Deduced); 2690} 2691