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1//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//===----------------------------------------------------------------------===/7//8//  This file implements C++ template instantiation for declarations.9//10//===----------------------------------------------------------------------===/11 12#include "TreeTransform.h"13#include "clang/AST/ASTConsumer.h"14#include "clang/AST/ASTContext.h"15#include "clang/AST/ASTMutationListener.h"16#include "clang/AST/DeclTemplate.h"17#include "clang/AST/DependentDiagnostic.h"18#include "clang/AST/Expr.h"19#include "clang/AST/ExprCXX.h"20#include "clang/AST/PrettyDeclStackTrace.h"21#include "clang/AST/TypeLoc.h"22#include "clang/Basic/SourceManager.h"23#include "clang/Basic/TargetInfo.h"24#include "clang/Sema/EnterExpressionEvaluationContext.h"25#include "clang/Sema/Initialization.h"26#include "clang/Sema/Lookup.h"27#include "clang/Sema/ScopeInfo.h"28#include "clang/Sema/SemaAMDGPU.h"29#include "clang/Sema/SemaCUDA.h"30#include "clang/Sema/SemaHLSL.h"31#include "clang/Sema/SemaObjC.h"32#include "clang/Sema/SemaOpenMP.h"33#include "clang/Sema/SemaSwift.h"34#include "clang/Sema/Template.h"35#include "clang/Sema/TemplateInstCallback.h"36#include "llvm/Support/TimeProfiler.h"37#include <optional>38 39using namespace clang;40 41static bool isDeclWithinFunction(const Decl *D) {42  const DeclContext *DC = D->getDeclContext();43  if (DC->isFunctionOrMethod())44    return true;45 46  if (DC->isRecord())47    return cast<CXXRecordDecl>(DC)->isLocalClass();48 49  return false;50}51 52template<typename DeclT>53static bool SubstQualifier(Sema &SemaRef, const DeclT *OldDecl, DeclT *NewDecl,54                           const MultiLevelTemplateArgumentList &TemplateArgs) {55  if (!OldDecl->getQualifierLoc())56    return false;57 58  assert((NewDecl->getFriendObjectKind() ||59          !OldDecl->getLexicalDeclContext()->isDependentContext()) &&60         "non-friend with qualified name defined in dependent context");61  Sema::ContextRAII SavedContext(62      SemaRef,63      const_cast<DeclContext *>(NewDecl->getFriendObjectKind()64                                    ? NewDecl->getLexicalDeclContext()65                                    : OldDecl->getLexicalDeclContext()));66 67  NestedNameSpecifierLoc NewQualifierLoc68      = SemaRef.SubstNestedNameSpecifierLoc(OldDecl->getQualifierLoc(),69                                            TemplateArgs);70 71  if (!NewQualifierLoc)72    return true;73 74  NewDecl->setQualifierInfo(NewQualifierLoc);75  return false;76}77 78bool TemplateDeclInstantiator::SubstQualifier(const DeclaratorDecl *OldDecl,79                                              DeclaratorDecl *NewDecl) {80  return ::SubstQualifier(SemaRef, OldDecl, NewDecl, TemplateArgs);81}82 83bool TemplateDeclInstantiator::SubstQualifier(const TagDecl *OldDecl,84                                              TagDecl *NewDecl) {85  return ::SubstQualifier(SemaRef, OldDecl, NewDecl, TemplateArgs);86}87 88// Include attribute instantiation code.89#include "clang/Sema/AttrTemplateInstantiate.inc"90 91static void instantiateDependentAlignedAttr(92    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,93    const AlignedAttr *Aligned, Decl *New, bool IsPackExpansion) {94  if (Aligned->isAlignmentExpr()) {95    // The alignment expression is a constant expression.96    EnterExpressionEvaluationContext Unevaluated(97        S, Sema::ExpressionEvaluationContext::ConstantEvaluated);98    ExprResult Result = S.SubstExpr(Aligned->getAlignmentExpr(), TemplateArgs);99    if (!Result.isInvalid())100      S.AddAlignedAttr(New, *Aligned, Result.getAs<Expr>(), IsPackExpansion);101  } else {102    if (TypeSourceInfo *Result =103            S.SubstType(Aligned->getAlignmentType(), TemplateArgs,104                        Aligned->getLocation(), DeclarationName())) {105      if (!S.CheckAlignasTypeArgument(Aligned->getSpelling(), Result,106                                      Aligned->getLocation(),107                                      Result->getTypeLoc().getSourceRange()))108        S.AddAlignedAttr(New, *Aligned, Result, IsPackExpansion);109    }110  }111}112 113static void instantiateDependentAlignedAttr(114    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,115    const AlignedAttr *Aligned, Decl *New) {116  if (!Aligned->isPackExpansion()) {117    instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);118    return;119  }120 121  SmallVector<UnexpandedParameterPack, 2> Unexpanded;122  if (Aligned->isAlignmentExpr())123    S.collectUnexpandedParameterPacks(Aligned->getAlignmentExpr(),124                                      Unexpanded);125  else126    S.collectUnexpandedParameterPacks(Aligned->getAlignmentType()->getTypeLoc(),127                                      Unexpanded);128  assert(!Unexpanded.empty() && "Pack expansion without parameter packs?");129 130  // Determine whether we can expand this attribute pack yet.131  bool Expand = true, RetainExpansion = false;132  UnsignedOrNone NumExpansions = std::nullopt;133  // FIXME: Use the actual location of the ellipsis.134  SourceLocation EllipsisLoc = Aligned->getLocation();135  if (S.CheckParameterPacksForExpansion(EllipsisLoc, Aligned->getRange(),136                                        Unexpanded, TemplateArgs,137                                        /*FailOnPackProducingTemplates=*/true,138                                        Expand, RetainExpansion, NumExpansions))139    return;140 141  if (!Expand) {142    Sema::ArgPackSubstIndexRAII SubstIndex(S, std::nullopt);143    instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, true);144  } else {145    for (unsigned I = 0; I != *NumExpansions; ++I) {146      Sema::ArgPackSubstIndexRAII SubstIndex(S, I);147      instantiateDependentAlignedAttr(S, TemplateArgs, Aligned, New, false);148    }149  }150}151 152static void instantiateDependentAssumeAlignedAttr(153    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,154    const AssumeAlignedAttr *Aligned, Decl *New) {155  // The alignment expression is a constant expression.156  EnterExpressionEvaluationContext Unevaluated(157      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);158 159  Expr *E, *OE = nullptr;160  ExprResult Result = S.SubstExpr(Aligned->getAlignment(), TemplateArgs);161  if (Result.isInvalid())162    return;163  E = Result.getAs<Expr>();164 165  if (Aligned->getOffset()) {166    Result = S.SubstExpr(Aligned->getOffset(), TemplateArgs);167    if (Result.isInvalid())168      return;169    OE = Result.getAs<Expr>();170  }171 172  S.AddAssumeAlignedAttr(New, *Aligned, E, OE);173}174 175static void instantiateDependentAlignValueAttr(176    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,177    const AlignValueAttr *Aligned, Decl *New) {178  // The alignment expression is a constant expression.179  EnterExpressionEvaluationContext Unevaluated(180      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);181  ExprResult Result = S.SubstExpr(Aligned->getAlignment(), TemplateArgs);182  if (!Result.isInvalid())183    S.AddAlignValueAttr(New, *Aligned, Result.getAs<Expr>());184}185 186static void instantiateDependentAllocAlignAttr(187    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,188    const AllocAlignAttr *Align, Decl *New) {189  Expr *Param = IntegerLiteral::Create(190      S.getASTContext(),191      llvm::APInt(64, Align->getParamIndex().getSourceIndex()),192      S.getASTContext().UnsignedLongLongTy, Align->getLocation());193  S.AddAllocAlignAttr(New, *Align, Param);194}195 196static void instantiateDependentAnnotationAttr(197    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,198    const AnnotateAttr *Attr, Decl *New) {199  EnterExpressionEvaluationContext Unevaluated(200      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);201 202  // If the attribute has delayed arguments it will have to instantiate those203  // and handle them as new arguments for the attribute.204  bool HasDelayedArgs = Attr->delayedArgs_size();205 206  ArrayRef<Expr *> ArgsToInstantiate =207      HasDelayedArgs208          ? ArrayRef<Expr *>{Attr->delayedArgs_begin(), Attr->delayedArgs_end()}209          : ArrayRef<Expr *>{Attr->args_begin(), Attr->args_end()};210 211  SmallVector<Expr *, 4> Args;212  if (S.SubstExprs(ArgsToInstantiate,213                   /*IsCall=*/false, TemplateArgs, Args))214    return;215 216  StringRef Str = Attr->getAnnotation();217  if (HasDelayedArgs) {218    if (Args.size() < 1) {219      S.Diag(Attr->getLoc(), diag::err_attribute_too_few_arguments)220          << Attr << 1;221      return;222    }223 224    if (!S.checkStringLiteralArgumentAttr(*Attr, Args[0], Str))225      return;226 227    llvm::SmallVector<Expr *, 4> ActualArgs;228    ActualArgs.insert(ActualArgs.begin(), Args.begin() + 1, Args.end());229    std::swap(Args, ActualArgs);230  }231  auto *AA = S.CreateAnnotationAttr(*Attr, Str, Args);232  if (AA) {233    New->addAttr(AA);234  }235}236 237template <typename Attr>238static void sharedInstantiateConstructorDestructorAttr(239    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs, const Attr *A,240    Decl *New, ASTContext &C) {241  Expr *tempInstPriority = nullptr;242  {243    EnterExpressionEvaluationContext Unevaluated(244        S, Sema::ExpressionEvaluationContext::Unevaluated);245    ExprResult Result = S.SubstExpr(A->getPriority(), TemplateArgs);246    if (Result.isInvalid())247      return;248    if (Result.isUsable()) {249      tempInstPriority = Result.get();250      if (std::optional<llvm::APSInt> CE =251              tempInstPriority->getIntegerConstantExpr(C)) {252        // Consistent with non-templated priority arguments, which must fit in a253        // 32-bit unsigned integer.254        if (!CE->isIntN(32)) {255          S.Diag(tempInstPriority->getExprLoc(), diag::err_ice_too_large)256              << toString(*CE, 10, false) << /*Size=*/32 << /*Unsigned=*/1;257          return;258        }259      }260    }261  }262  New->addAttr(Attr::Create(C, tempInstPriority, *A));263}264 265static Expr *instantiateDependentFunctionAttrCondition(266    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,267    const Attr *A, Expr *OldCond, const Decl *Tmpl, FunctionDecl *New) {268  Expr *Cond = nullptr;269  {270    Sema::ContextRAII SwitchContext(S, New);271    EnterExpressionEvaluationContext Unevaluated(272        S, Sema::ExpressionEvaluationContext::ConstantEvaluated);273    ExprResult Result = S.SubstExpr(OldCond, TemplateArgs);274    if (Result.isInvalid())275      return nullptr;276    Cond = Result.getAs<Expr>();277  }278  if (!Cond->isTypeDependent()) {279    ExprResult Converted = S.PerformContextuallyConvertToBool(Cond);280    if (Converted.isInvalid())281      return nullptr;282    Cond = Converted.get();283  }284 285  SmallVector<PartialDiagnosticAt, 8> Diags;286  if (OldCond->isValueDependent() && !Cond->isValueDependent() &&287      !Expr::isPotentialConstantExprUnevaluated(Cond, New, Diags)) {288    S.Diag(A->getLocation(), diag::err_attr_cond_never_constant_expr) << A;289    for (const auto &P : Diags)290      S.Diag(P.first, P.second);291    return nullptr;292  }293  return Cond;294}295 296static void instantiateDependentEnableIfAttr(297    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,298    const EnableIfAttr *EIA, const Decl *Tmpl, FunctionDecl *New) {299  Expr *Cond = instantiateDependentFunctionAttrCondition(300      S, TemplateArgs, EIA, EIA->getCond(), Tmpl, New);301 302  if (Cond)303    New->addAttr(new (S.getASTContext()) EnableIfAttr(S.getASTContext(), *EIA,304                                                      Cond, EIA->getMessage()));305}306 307static void instantiateDependentDiagnoseIfAttr(308    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,309    const DiagnoseIfAttr *DIA, const Decl *Tmpl, FunctionDecl *New) {310  Expr *Cond = instantiateDependentFunctionAttrCondition(311      S, TemplateArgs, DIA, DIA->getCond(), Tmpl, New);312 313  if (Cond)314    New->addAttr(new (S.getASTContext()) DiagnoseIfAttr(315        S.getASTContext(), *DIA, Cond, DIA->getMessage(),316        DIA->getDefaultSeverity(), DIA->getWarningGroup(),317        DIA->getArgDependent(), New));318}319 320// Constructs and adds to New a new instance of CUDALaunchBoundsAttr using321// template A as the base and arguments from TemplateArgs.322static void instantiateDependentCUDALaunchBoundsAttr(323    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,324    const CUDALaunchBoundsAttr &Attr, Decl *New) {325  // The alignment expression is a constant expression.326  EnterExpressionEvaluationContext Unevaluated(327      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);328 329  ExprResult Result = S.SubstExpr(Attr.getMaxThreads(), TemplateArgs);330  if (Result.isInvalid())331    return;332  Expr *MaxThreads = Result.getAs<Expr>();333 334  Expr *MinBlocks = nullptr;335  if (Attr.getMinBlocks()) {336    Result = S.SubstExpr(Attr.getMinBlocks(), TemplateArgs);337    if (Result.isInvalid())338      return;339    MinBlocks = Result.getAs<Expr>();340  }341 342  Expr *MaxBlocks = nullptr;343  if (Attr.getMaxBlocks()) {344    Result = S.SubstExpr(Attr.getMaxBlocks(), TemplateArgs);345    if (Result.isInvalid())346      return;347    MaxBlocks = Result.getAs<Expr>();348  }349 350  S.AddLaunchBoundsAttr(New, Attr, MaxThreads, MinBlocks, MaxBlocks);351}352 353static void354instantiateDependentModeAttr(Sema &S,355                             const MultiLevelTemplateArgumentList &TemplateArgs,356                             const ModeAttr &Attr, Decl *New) {357  S.AddModeAttr(New, Attr, Attr.getMode(),358                /*InInstantiation=*/true);359}360 361/// Instantiation of 'declare simd' attribute and its arguments.362static void instantiateOMPDeclareSimdDeclAttr(363    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,364    const OMPDeclareSimdDeclAttr &Attr, Decl *New) {365  // Allow 'this' in clauses with varlist.366  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(New))367    New = FTD->getTemplatedDecl();368  auto *FD = cast<FunctionDecl>(New);369  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(FD->getDeclContext());370  SmallVector<Expr *, 4> Uniforms, Aligneds, Alignments, Linears, Steps;371  SmallVector<unsigned, 4> LinModifiers;372 373  auto SubstExpr = [&](Expr *E) -> ExprResult {374    if (auto *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))375      if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {376        Sema::ContextRAII SavedContext(S, FD);377        LocalInstantiationScope Local(S);378        if (FD->getNumParams() > PVD->getFunctionScopeIndex())379          Local.InstantiatedLocal(380              PVD, FD->getParamDecl(PVD->getFunctionScopeIndex()));381        return S.SubstExpr(E, TemplateArgs);382      }383    Sema::CXXThisScopeRAII ThisScope(S, ThisContext, Qualifiers(),384                                     FD->isCXXInstanceMember());385    return S.SubstExpr(E, TemplateArgs);386  };387 388  // Substitute a single OpenMP clause, which is a potentially-evaluated389  // full-expression.390  auto Subst = [&](Expr *E) -> ExprResult {391    EnterExpressionEvaluationContext Evaluated(392        S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);393    ExprResult Res = SubstExpr(E);394    if (Res.isInvalid())395      return Res;396    return S.ActOnFinishFullExpr(Res.get(), false);397  };398 399  ExprResult Simdlen;400  if (auto *E = Attr.getSimdlen())401    Simdlen = Subst(E);402 403  if (Attr.uniforms_size() > 0) {404    for(auto *E : Attr.uniforms()) {405      ExprResult Inst = Subst(E);406      if (Inst.isInvalid())407        continue;408      Uniforms.push_back(Inst.get());409    }410  }411 412  auto AI = Attr.alignments_begin();413  for (auto *E : Attr.aligneds()) {414    ExprResult Inst = Subst(E);415    if (Inst.isInvalid())416      continue;417    Aligneds.push_back(Inst.get());418    Inst = ExprEmpty();419    if (*AI)420      Inst = S.SubstExpr(*AI, TemplateArgs);421    Alignments.push_back(Inst.get());422    ++AI;423  }424 425  auto SI = Attr.steps_begin();426  for (auto *E : Attr.linears()) {427    ExprResult Inst = Subst(E);428    if (Inst.isInvalid())429      continue;430    Linears.push_back(Inst.get());431    Inst = ExprEmpty();432    if (*SI)433      Inst = S.SubstExpr(*SI, TemplateArgs);434    Steps.push_back(Inst.get());435    ++SI;436  }437  LinModifiers.append(Attr.modifiers_begin(), Attr.modifiers_end());438  (void)S.OpenMP().ActOnOpenMPDeclareSimdDirective(439      S.ConvertDeclToDeclGroup(New), Attr.getBranchState(), Simdlen.get(),440      Uniforms, Aligneds, Alignments, Linears, LinModifiers, Steps,441      Attr.getRange());442}443 444/// Instantiation of 'declare variant' attribute and its arguments.445static void instantiateOMPDeclareVariantAttr(446    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,447    const OMPDeclareVariantAttr &Attr, Decl *New) {448  // Allow 'this' in clauses with varlist.449  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(New))450    New = FTD->getTemplatedDecl();451  auto *FD = cast<FunctionDecl>(New);452  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(FD->getDeclContext());453 454  auto &&SubstExpr = [FD, ThisContext, &S, &TemplateArgs](Expr *E) {455    if (auto *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))456      if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {457        Sema::ContextRAII SavedContext(S, FD);458        LocalInstantiationScope Local(S);459        if (FD->getNumParams() > PVD->getFunctionScopeIndex())460          Local.InstantiatedLocal(461              PVD, FD->getParamDecl(PVD->getFunctionScopeIndex()));462        return S.SubstExpr(E, TemplateArgs);463      }464    Sema::CXXThisScopeRAII ThisScope(S, ThisContext, Qualifiers(),465                                     FD->isCXXInstanceMember());466    return S.SubstExpr(E, TemplateArgs);467  };468 469  // Substitute a single OpenMP clause, which is a potentially-evaluated470  // full-expression.471  auto &&Subst = [&SubstExpr, &S](Expr *E) {472    EnterExpressionEvaluationContext Evaluated(473        S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);474    ExprResult Res = SubstExpr(E);475    if (Res.isInvalid())476      return Res;477    return S.ActOnFinishFullExpr(Res.get(), false);478  };479 480  ExprResult VariantFuncRef;481  if (Expr *E = Attr.getVariantFuncRef()) {482    // Do not mark function as is used to prevent its emission if this is the483    // only place where it is used.484    EnterExpressionEvaluationContext Unevaluated(485        S, Sema::ExpressionEvaluationContext::ConstantEvaluated);486    VariantFuncRef = Subst(E);487  }488 489  // Copy the template version of the OMPTraitInfo and run substitute on all490  // score and condition expressiosn.491  OMPTraitInfo &TI = S.getASTContext().getNewOMPTraitInfo();492  TI = *Attr.getTraitInfos();493 494  // Try to substitute template parameters in score and condition expressions.495  auto SubstScoreOrConditionExpr = [&S, Subst](Expr *&E, bool) {496    if (E) {497      EnterExpressionEvaluationContext Unevaluated(498          S, Sema::ExpressionEvaluationContext::ConstantEvaluated);499      ExprResult ER = Subst(E);500      if (ER.isUsable())501        E = ER.get();502      else503        return true;504    }505    return false;506  };507  if (TI.anyScoreOrCondition(SubstScoreOrConditionExpr))508    return;509 510  Expr *E = VariantFuncRef.get();511 512  // Check function/variant ref for `omp declare variant` but not for `omp513  // begin declare variant` (which use implicit attributes).514  std::optional<std::pair<FunctionDecl *, Expr *>> DeclVarData =515      S.OpenMP().checkOpenMPDeclareVariantFunction(516          S.ConvertDeclToDeclGroup(New), E, TI, Attr.appendArgs_size(),517          Attr.getRange());518 519  if (!DeclVarData)520    return;521 522  E = DeclVarData->second;523  FD = DeclVarData->first;524 525  if (auto *VariantDRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) {526    if (auto *VariantFD = dyn_cast<FunctionDecl>(VariantDRE->getDecl())) {527      if (auto *VariantFTD = VariantFD->getDescribedFunctionTemplate()) {528        if (!VariantFTD->isThisDeclarationADefinition())529          return;530        Sema::TentativeAnalysisScope Trap(S);531        const TemplateArgumentList *TAL = TemplateArgumentList::CreateCopy(532            S.Context, TemplateArgs.getInnermost());533 534        auto *SubstFD = S.InstantiateFunctionDeclaration(VariantFTD, TAL,535                                                         New->getLocation());536        if (!SubstFD)537          return;538        QualType NewType = S.Context.mergeFunctionTypes(539            SubstFD->getType(), FD->getType(),540            /* OfBlockPointer */ false,541            /* Unqualified */ false, /* AllowCXX */ true);542        if (NewType.isNull())543          return;544        S.InstantiateFunctionDefinition(545            New->getLocation(), SubstFD, /* Recursive */ true,546            /* DefinitionRequired */ false, /* AtEndOfTU */ false);547        SubstFD->setInstantiationIsPending(!SubstFD->isDefined());548        E = DeclRefExpr::Create(S.Context, NestedNameSpecifierLoc(),549                                SourceLocation(), SubstFD,550                                /* RefersToEnclosingVariableOrCapture */ false,551                                /* NameLoc */ SubstFD->getLocation(),552                                SubstFD->getType(), ExprValueKind::VK_PRValue);553      }554    }555  }556 557  SmallVector<Expr *, 8> NothingExprs;558  SmallVector<Expr *, 8> NeedDevicePtrExprs;559  SmallVector<Expr *, 8> NeedDeviceAddrExprs;560  SmallVector<OMPInteropInfo, 4> AppendArgs;561 562  for (Expr *E : Attr.adjustArgsNothing()) {563    ExprResult ER = Subst(E);564    if (ER.isInvalid())565      continue;566    NothingExprs.push_back(ER.get());567  }568  for (Expr *E : Attr.adjustArgsNeedDevicePtr()) {569    ExprResult ER = Subst(E);570    if (ER.isInvalid())571      continue;572    NeedDevicePtrExprs.push_back(ER.get());573  }574  for (Expr *E : Attr.adjustArgsNeedDeviceAddr()) {575    ExprResult ER = Subst(E);576    if (ER.isInvalid())577      continue;578    NeedDeviceAddrExprs.push_back(ER.get());579  }580  for (OMPInteropInfo &II : Attr.appendArgs()) {581    // When prefer_type is implemented for append_args handle them here too.582    AppendArgs.emplace_back(II.IsTarget, II.IsTargetSync);583  }584 585  S.OpenMP().ActOnOpenMPDeclareVariantDirective(586      FD, E, TI, NothingExprs, NeedDevicePtrExprs, NeedDeviceAddrExprs,587      AppendArgs, SourceLocation(), SourceLocation(), Attr.getRange());588}589 590static void instantiateDependentAMDGPUFlatWorkGroupSizeAttr(591    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,592    const AMDGPUFlatWorkGroupSizeAttr &Attr, Decl *New) {593  // Both min and max expression are constant expressions.594  EnterExpressionEvaluationContext Unevaluated(595      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);596 597  ExprResult Result = S.SubstExpr(Attr.getMin(), TemplateArgs);598  if (Result.isInvalid())599    return;600  Expr *MinExpr = Result.getAs<Expr>();601 602  Result = S.SubstExpr(Attr.getMax(), TemplateArgs);603  if (Result.isInvalid())604    return;605  Expr *MaxExpr = Result.getAs<Expr>();606 607  S.AMDGPU().addAMDGPUFlatWorkGroupSizeAttr(New, Attr, MinExpr, MaxExpr);608}609 610static void instantiateDependentReqdWorkGroupSizeAttr(611    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,612    const ReqdWorkGroupSizeAttr &Attr, Decl *New) {613  // Both min and max expression are constant expressions.614  EnterExpressionEvaluationContext Unevaluated(615      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);616 617  ExprResult Result = S.SubstExpr(Attr.getXDim(), TemplateArgs);618  if (Result.isInvalid())619    return;620  Expr *X = Result.getAs<Expr>();621 622  Result = S.SubstExpr(Attr.getYDim(), TemplateArgs);623  if (Result.isInvalid())624    return;625  Expr *Y = Result.getAs<Expr>();626 627  Result = S.SubstExpr(Attr.getZDim(), TemplateArgs);628  if (Result.isInvalid())629    return;630  Expr *Z = Result.getAs<Expr>();631 632  ASTContext &Context = S.getASTContext();633  New->addAttr(::new (Context) ReqdWorkGroupSizeAttr(Context, Attr, X, Y, Z));634}635 636ExplicitSpecifier Sema::instantiateExplicitSpecifier(637    const MultiLevelTemplateArgumentList &TemplateArgs, ExplicitSpecifier ES) {638  if (!ES.getExpr())639    return ES;640  Expr *OldCond = ES.getExpr();641  Expr *Cond = nullptr;642  {643    EnterExpressionEvaluationContext Unevaluated(644        *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);645    ExprResult SubstResult = SubstExpr(OldCond, TemplateArgs);646    if (SubstResult.isInvalid()) {647      return ExplicitSpecifier::Invalid();648    }649    Cond = SubstResult.get();650  }651  ExplicitSpecifier Result(Cond, ES.getKind());652  if (!Cond->isTypeDependent())653    tryResolveExplicitSpecifier(Result);654  return Result;655}656 657static void instantiateDependentAMDGPUWavesPerEUAttr(658    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,659    const AMDGPUWavesPerEUAttr &Attr, Decl *New) {660  // Both min and max expression are constant expressions.661  EnterExpressionEvaluationContext Unevaluated(662      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);663 664  ExprResult Result = S.SubstExpr(Attr.getMin(), TemplateArgs);665  if (Result.isInvalid())666    return;667  Expr *MinExpr = Result.getAs<Expr>();668 669  Expr *MaxExpr = nullptr;670  if (auto Max = Attr.getMax()) {671    Result = S.SubstExpr(Max, TemplateArgs);672    if (Result.isInvalid())673      return;674    MaxExpr = Result.getAs<Expr>();675  }676 677  S.AMDGPU().addAMDGPUWavesPerEUAttr(New, Attr, MinExpr, MaxExpr);678}679 680static void instantiateDependentAMDGPUMaxNumWorkGroupsAttr(681    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,682    const AMDGPUMaxNumWorkGroupsAttr &Attr, Decl *New) {683  EnterExpressionEvaluationContext Unevaluated(684      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);685 686  Expr *XExpr = nullptr;687  Expr *YExpr = nullptr;688  Expr *ZExpr = nullptr;689 690  if (Attr.getMaxNumWorkGroupsX()) {691    ExprResult ResultX = S.SubstExpr(Attr.getMaxNumWorkGroupsX(), TemplateArgs);692    if (ResultX.isUsable())693      XExpr = ResultX.getAs<Expr>();694  }695 696  if (Attr.getMaxNumWorkGroupsY()) {697    ExprResult ResultY = S.SubstExpr(Attr.getMaxNumWorkGroupsY(), TemplateArgs);698    if (ResultY.isUsable())699      YExpr = ResultY.getAs<Expr>();700  }701 702  if (Attr.getMaxNumWorkGroupsZ()) {703    ExprResult ResultZ = S.SubstExpr(Attr.getMaxNumWorkGroupsZ(), TemplateArgs);704    if (ResultZ.isUsable())705      ZExpr = ResultZ.getAs<Expr>();706  }707 708  if (XExpr)709    S.AMDGPU().addAMDGPUMaxNumWorkGroupsAttr(New, Attr, XExpr, YExpr, ZExpr);710}711 712static void instantiateDependentCUDAClusterDimsAttr(713    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,714    const CUDAClusterDimsAttr &Attr, Decl *New) {715  EnterExpressionEvaluationContext Unevaluated(716      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);717 718  auto SubstElt = [&S, &TemplateArgs](Expr *E) {719    return E ? S.SubstExpr(E, TemplateArgs).get() : nullptr;720  };721 722  Expr *XExpr = SubstElt(Attr.getX());723  Expr *YExpr = SubstElt(Attr.getY());724  Expr *ZExpr = SubstElt(Attr.getZ());725 726  S.addClusterDimsAttr(New, Attr, XExpr, YExpr, ZExpr);727}728 729// This doesn't take any template parameters, but we have a custom action that730// needs to happen when the kernel itself is instantiated. We need to run the731// ItaniumMangler to mark the names required to name this kernel.732static void instantiateDependentSYCLKernelAttr(733    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,734    const SYCLKernelAttr &Attr, Decl *New) {735  New->addAttr(Attr.clone(S.getASTContext()));736}737 738/// Determine whether the attribute A might be relevant to the declaration D.739/// If not, we can skip instantiating it. The attribute may or may not have740/// been instantiated yet.741static bool isRelevantAttr(Sema &S, const Decl *D, const Attr *A) {742  // 'preferred_name' is only relevant to the matching specialization of the743  // template.744  if (const auto *PNA = dyn_cast<PreferredNameAttr>(A)) {745    QualType T = PNA->getTypedefType();746    const auto *RD = cast<CXXRecordDecl>(D);747    if (!T->isDependentType() && !RD->isDependentContext() &&748        !declaresSameEntity(T->getAsCXXRecordDecl(), RD))749      return false;750    for (const auto *ExistingPNA : D->specific_attrs<PreferredNameAttr>())751      if (S.Context.hasSameType(ExistingPNA->getTypedefType(),752                                PNA->getTypedefType()))753        return false;754    return true;755  }756 757  if (const auto *BA = dyn_cast<BuiltinAttr>(A)) {758    const FunctionDecl *FD = dyn_cast<FunctionDecl>(D);759    switch (BA->getID()) {760    case Builtin::BIforward:761      // Do not treat 'std::forward' as a builtin if it takes an rvalue reference762      // type and returns an lvalue reference type. The library implementation763      // will produce an error in this case; don't get in its way.764      if (FD && FD->getNumParams() >= 1 &&765          FD->getParamDecl(0)->getType()->isRValueReferenceType() &&766          FD->getReturnType()->isLValueReferenceType()) {767        return false;768      }769      [[fallthrough]];770    case Builtin::BImove:771    case Builtin::BImove_if_noexcept:772      // HACK: Super-old versions of libc++ (3.1 and earlier) provide773      // std::forward and std::move overloads that sometimes return by value774      // instead of by reference when building in C++98 mode. Don't treat such775      // cases as builtins.776      if (FD && !FD->getReturnType()->isReferenceType())777        return false;778      break;779    }780  }781 782  return true;783}784 785static void instantiateDependentHLSLParamModifierAttr(786    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,787    const HLSLParamModifierAttr *Attr, const Decl *Old, Decl *New) {788  ParmVarDecl *NewParm = cast<ParmVarDecl>(New);789  NewParm->addAttr(Attr->clone(S.getASTContext()));790 791  const Type *OldParmTy = cast<ParmVarDecl>(Old)->getType().getTypePtr();792  if (OldParmTy->isDependentType() && Attr->isAnyOut())793    NewParm->setType(S.HLSL().getInoutParameterType(NewParm->getType()));794 795  assert(796      (!Attr->isAnyOut() || (NewParm->getType().isRestrictQualified() &&797                             NewParm->getType()->isReferenceType())) &&798      "out or inout parameter type must be a reference and restrict qualified");799}800 801static void instantiateDependentMallocSpanAttr(Sema &S,802                                               const MallocSpanAttr *Attr,803                                               Decl *New) {804  QualType RT = getFunctionOrMethodResultType(New);805  if (!S.CheckSpanLikeType(*Attr, RT))806    New->addAttr(Attr->clone(S.getASTContext()));807}808 809void Sema::InstantiateAttrsForDecl(810    const MultiLevelTemplateArgumentList &TemplateArgs, const Decl *Tmpl,811    Decl *New, LateInstantiatedAttrVec *LateAttrs,812    LocalInstantiationScope *OuterMostScope) {813  if (NamedDecl *ND = dyn_cast<NamedDecl>(New)) {814    // FIXME: This function is called multiple times for the same template815    // specialization. We should only instantiate attributes that were added816    // since the previous instantiation.817    for (const auto *TmplAttr : Tmpl->attrs()) {818      if (!isRelevantAttr(*this, New, TmplAttr))819        continue;820 821      // FIXME: If any of the special case versions from InstantiateAttrs become822      // applicable to template declaration, we'll need to add them here.823      CXXThisScopeRAII ThisScope(824          *this, dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext()),825          Qualifiers(), ND->isCXXInstanceMember());826 827      Attr *NewAttr = sema::instantiateTemplateAttributeForDecl(828          TmplAttr, Context, *this, TemplateArgs);829      if (NewAttr && isRelevantAttr(*this, New, NewAttr))830        New->addAttr(NewAttr);831    }832  }833}834 835static Sema::RetainOwnershipKind836attrToRetainOwnershipKind(const Attr *A) {837  switch (A->getKind()) {838  case clang::attr::CFConsumed:839    return Sema::RetainOwnershipKind::CF;840  case clang::attr::OSConsumed:841    return Sema::RetainOwnershipKind::OS;842  case clang::attr::NSConsumed:843    return Sema::RetainOwnershipKind::NS;844  default:845    llvm_unreachable("Wrong argument supplied");846  }847}848 849// Implementation is down with the rest of the OpenACC Decl instantiations.850static void instantiateDependentOpenACCRoutineDeclAttr(851    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,852    const OpenACCRoutineDeclAttr *OldAttr, const Decl *Old, Decl *New);853 854void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,855                            const Decl *Tmpl, Decl *New,856                            LateInstantiatedAttrVec *LateAttrs,857                            LocalInstantiationScope *OuterMostScope) {858  for (const auto *TmplAttr : Tmpl->attrs()) {859    if (!isRelevantAttr(*this, New, TmplAttr))860      continue;861 862    // FIXME: This should be generalized to more than just the AlignedAttr.863    const AlignedAttr *Aligned = dyn_cast<AlignedAttr>(TmplAttr);864    if (Aligned && Aligned->isAlignmentDependent()) {865      instantiateDependentAlignedAttr(*this, TemplateArgs, Aligned, New);866      continue;867    }868 869    if (const auto *AssumeAligned = dyn_cast<AssumeAlignedAttr>(TmplAttr)) {870      instantiateDependentAssumeAlignedAttr(*this, TemplateArgs, AssumeAligned, New);871      continue;872    }873 874    if (const auto *AlignValue = dyn_cast<AlignValueAttr>(TmplAttr)) {875      instantiateDependentAlignValueAttr(*this, TemplateArgs, AlignValue, New);876      continue;877    }878 879    if (const auto *AllocAlign = dyn_cast<AllocAlignAttr>(TmplAttr)) {880      instantiateDependentAllocAlignAttr(*this, TemplateArgs, AllocAlign, New);881      continue;882    }883 884    if (const auto *Annotate = dyn_cast<AnnotateAttr>(TmplAttr)) {885      instantiateDependentAnnotationAttr(*this, TemplateArgs, Annotate, New);886      continue;887    }888 889    if (auto *Constructor = dyn_cast<ConstructorAttr>(TmplAttr)) {890      sharedInstantiateConstructorDestructorAttr(*this, TemplateArgs,891                                                 Constructor, New, Context);892      continue;893    }894 895    if (auto *Destructor = dyn_cast<DestructorAttr>(TmplAttr)) {896      sharedInstantiateConstructorDestructorAttr(*this, TemplateArgs,897                                                 Destructor, New, Context);898      continue;899    }900 901    if (const auto *EnableIf = dyn_cast<EnableIfAttr>(TmplAttr)) {902      instantiateDependentEnableIfAttr(*this, TemplateArgs, EnableIf, Tmpl,903                                       cast<FunctionDecl>(New));904      continue;905    }906 907    if (const auto *DiagnoseIf = dyn_cast<DiagnoseIfAttr>(TmplAttr)) {908      instantiateDependentDiagnoseIfAttr(*this, TemplateArgs, DiagnoseIf, Tmpl,909                                         cast<FunctionDecl>(New));910      continue;911    }912 913    if (const auto *CUDALaunchBounds =914            dyn_cast<CUDALaunchBoundsAttr>(TmplAttr)) {915      instantiateDependentCUDALaunchBoundsAttr(*this, TemplateArgs,916                                               *CUDALaunchBounds, New);917      continue;918    }919 920    if (const auto *Mode = dyn_cast<ModeAttr>(TmplAttr)) {921      instantiateDependentModeAttr(*this, TemplateArgs, *Mode, New);922      continue;923    }924 925    if (const auto *OMPAttr = dyn_cast<OMPDeclareSimdDeclAttr>(TmplAttr)) {926      instantiateOMPDeclareSimdDeclAttr(*this, TemplateArgs, *OMPAttr, New);927      continue;928    }929 930    if (const auto *OMPAttr = dyn_cast<OMPDeclareVariantAttr>(TmplAttr)) {931      instantiateOMPDeclareVariantAttr(*this, TemplateArgs, *OMPAttr, New);932      continue;933    }934 935    if (const auto *ReqdWorkGroupSize =936            dyn_cast<ReqdWorkGroupSizeAttr>(TmplAttr)) {937      instantiateDependentReqdWorkGroupSizeAttr(*this, TemplateArgs,938                                                *ReqdWorkGroupSize, New);939    }940 941    if (const auto *AMDGPUFlatWorkGroupSize =942            dyn_cast<AMDGPUFlatWorkGroupSizeAttr>(TmplAttr)) {943      instantiateDependentAMDGPUFlatWorkGroupSizeAttr(944          *this, TemplateArgs, *AMDGPUFlatWorkGroupSize, New);945    }946 947    if (const auto *AMDGPUFlatWorkGroupSize =948            dyn_cast<AMDGPUWavesPerEUAttr>(TmplAttr)) {949      instantiateDependentAMDGPUWavesPerEUAttr(*this, TemplateArgs,950                                               *AMDGPUFlatWorkGroupSize, New);951    }952 953    if (const auto *AMDGPUMaxNumWorkGroups =954            dyn_cast<AMDGPUMaxNumWorkGroupsAttr>(TmplAttr)) {955      instantiateDependentAMDGPUMaxNumWorkGroupsAttr(956          *this, TemplateArgs, *AMDGPUMaxNumWorkGroups, New);957    }958 959    if (const auto *CUDAClusterDims = dyn_cast<CUDAClusterDimsAttr>(TmplAttr)) {960      instantiateDependentCUDAClusterDimsAttr(*this, TemplateArgs,961                                              *CUDAClusterDims, New);962    }963 964    if (const auto *ParamAttr = dyn_cast<HLSLParamModifierAttr>(TmplAttr)) {965      instantiateDependentHLSLParamModifierAttr(*this, TemplateArgs, ParamAttr,966                                                Tmpl, New);967      continue;968    }969 970    if (const auto *RoutineAttr = dyn_cast<OpenACCRoutineDeclAttr>(TmplAttr)) {971      instantiateDependentOpenACCRoutineDeclAttr(*this, TemplateArgs,972                                                 RoutineAttr, Tmpl, New);973      continue;974    }975 976    // Existing DLL attribute on the instantiation takes precedence.977    if (TmplAttr->getKind() == attr::DLLExport ||978        TmplAttr->getKind() == attr::DLLImport) {979      if (New->hasAttr<DLLExportAttr>() || New->hasAttr<DLLImportAttr>()) {980        continue;981      }982    }983 984    if (const auto *ABIAttr = dyn_cast<ParameterABIAttr>(TmplAttr)) {985      Swift().AddParameterABIAttr(New, *ABIAttr, ABIAttr->getABI());986      continue;987    }988 989    if (isa<NSConsumedAttr>(TmplAttr) || isa<OSConsumedAttr>(TmplAttr) ||990        isa<CFConsumedAttr>(TmplAttr)) {991      ObjC().AddXConsumedAttr(New, *TmplAttr,992                              attrToRetainOwnershipKind(TmplAttr),993                              /*template instantiation=*/true);994      continue;995    }996 997    if (auto *A = dyn_cast<PointerAttr>(TmplAttr)) {998      if (!New->hasAttr<PointerAttr>())999        New->addAttr(A->clone(Context));1000      continue;1001    }1002 1003    if (auto *A = dyn_cast<OwnerAttr>(TmplAttr)) {1004      if (!New->hasAttr<OwnerAttr>())1005        New->addAttr(A->clone(Context));1006      continue;1007    }1008 1009    if (auto *A = dyn_cast<SYCLKernelAttr>(TmplAttr)) {1010      instantiateDependentSYCLKernelAttr(*this, TemplateArgs, *A, New);1011      continue;1012    }1013 1014    if (auto *A = dyn_cast<CUDAGridConstantAttr>(TmplAttr)) {1015      if (!New->hasAttr<CUDAGridConstantAttr>())1016        New->addAttr(A->clone(Context));1017      continue;1018    }1019 1020    if (auto *A = dyn_cast<MallocSpanAttr>(TmplAttr)) {1021      instantiateDependentMallocSpanAttr(*this, A, New);1022      continue;1023    }1024 1025    if (auto *A = dyn_cast<CleanupAttr>(TmplAttr)) {1026      if (!New->hasAttr<CleanupAttr>()) {1027        auto *NewAttr = A->clone(Context);1028        NewAttr->setArgLoc(A->getArgLoc());1029        New->addAttr(NewAttr);1030      }1031      continue;1032    }1033 1034    assert(!TmplAttr->isPackExpansion());1035    if (TmplAttr->isLateParsed() && LateAttrs) {1036      // Late parsed attributes must be instantiated and attached after the1037      // enclosing class has been instantiated.  See Sema::InstantiateClass.1038      LocalInstantiationScope *Saved = nullptr;1039      if (CurrentInstantiationScope)1040        Saved = CurrentInstantiationScope->cloneScopes(OuterMostScope);1041      LateAttrs->push_back(LateInstantiatedAttribute(TmplAttr, Saved, New));1042    } else {1043      // Allow 'this' within late-parsed attributes.1044      auto *ND = cast<NamedDecl>(New);1045      auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext());1046      CXXThisScopeRAII ThisScope(*this, ThisContext, Qualifiers(),1047                                 ND->isCXXInstanceMember());1048 1049      Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,1050                                                         *this, TemplateArgs);1051      if (NewAttr && isRelevantAttr(*this, New, TmplAttr))1052        New->addAttr(NewAttr);1053    }1054  }1055}1056 1057void Sema::updateAttrsForLateParsedTemplate(const Decl *Pattern, Decl *Inst) {1058  for (const auto *Attr : Pattern->attrs()) {1059    if (auto *A = dyn_cast<StrictFPAttr>(Attr)) {1060      if (!Inst->hasAttr<StrictFPAttr>())1061        Inst->addAttr(A->clone(getASTContext()));1062      continue;1063    }1064  }1065}1066 1067void Sema::InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor) {1068  assert(Context.getTargetInfo().getCXXABI().isMicrosoft() &&1069         Ctor->isDefaultConstructor());1070  unsigned NumParams = Ctor->getNumParams();1071  if (NumParams == 0)1072    return;1073  DLLExportAttr *Attr = Ctor->getAttr<DLLExportAttr>();1074  if (!Attr)1075    return;1076  for (unsigned I = 0; I != NumParams; ++I) {1077    (void)CheckCXXDefaultArgExpr(Attr->getLocation(), Ctor,1078                                   Ctor->getParamDecl(I));1079    CleanupVarDeclMarking();1080  }1081}1082 1083/// Get the previous declaration of a declaration for the purposes of template1084/// instantiation. If this finds a previous declaration, then the previous1085/// declaration of the instantiation of D should be an instantiation of the1086/// result of this function.1087template<typename DeclT>1088static DeclT *getPreviousDeclForInstantiation(DeclT *D) {1089  DeclT *Result = D->getPreviousDecl();1090 1091  // If the declaration is within a class, and the previous declaration was1092  // merged from a different definition of that class, then we don't have a1093  // previous declaration for the purpose of template instantiation.1094  if (Result && isa<CXXRecordDecl>(D->getDeclContext()) &&1095      D->getLexicalDeclContext() != Result->getLexicalDeclContext())1096    return nullptr;1097 1098  return Result;1099}1100 1101Decl *1102TemplateDeclInstantiator::VisitTranslationUnitDecl(TranslationUnitDecl *D) {1103  llvm_unreachable("Translation units cannot be instantiated");1104}1105 1106Decl *TemplateDeclInstantiator::VisitHLSLBufferDecl(HLSLBufferDecl *Decl) {1107  llvm_unreachable("HLSL buffer declarations cannot be instantiated");1108}1109 1110Decl *TemplateDeclInstantiator::VisitHLSLRootSignatureDecl(1111    HLSLRootSignatureDecl *Decl) {1112  llvm_unreachable("HLSL root signature declarations cannot be instantiated");1113}1114 1115Decl *1116TemplateDeclInstantiator::VisitPragmaCommentDecl(PragmaCommentDecl *D) {1117  llvm_unreachable("pragma comment cannot be instantiated");1118}1119 1120Decl *TemplateDeclInstantiator::VisitPragmaDetectMismatchDecl(1121    PragmaDetectMismatchDecl *D) {1122  llvm_unreachable("pragma comment cannot be instantiated");1123}1124 1125Decl *1126TemplateDeclInstantiator::VisitExternCContextDecl(ExternCContextDecl *D) {1127  llvm_unreachable("extern \"C\" context cannot be instantiated");1128}1129 1130Decl *TemplateDeclInstantiator::VisitMSGuidDecl(MSGuidDecl *D) {1131  llvm_unreachable("GUID declaration cannot be instantiated");1132}1133 1134Decl *TemplateDeclInstantiator::VisitUnnamedGlobalConstantDecl(1135    UnnamedGlobalConstantDecl *D) {1136  llvm_unreachable("UnnamedGlobalConstantDecl cannot be instantiated");1137}1138 1139Decl *TemplateDeclInstantiator::VisitTemplateParamObjectDecl(1140    TemplateParamObjectDecl *D) {1141  llvm_unreachable("template parameter objects cannot be instantiated");1142}1143 1144Decl *1145TemplateDeclInstantiator::VisitLabelDecl(LabelDecl *D) {1146  LabelDecl *Inst = LabelDecl::Create(SemaRef.Context, Owner, D->getLocation(),1147                                      D->getIdentifier());1148  SemaRef.InstantiateAttrs(TemplateArgs, D, Inst, LateAttrs, StartingScope);1149  Owner->addDecl(Inst);1150  return Inst;1151}1152 1153Decl *1154TemplateDeclInstantiator::VisitNamespaceDecl(NamespaceDecl *D) {1155  llvm_unreachable("Namespaces cannot be instantiated");1156}1157 1158namespace {1159class OpenACCDeclClauseInstantiator final1160    : public OpenACCClauseVisitor<OpenACCDeclClauseInstantiator> {1161  Sema &SemaRef;1162  const MultiLevelTemplateArgumentList &MLTAL;1163  ArrayRef<OpenACCClause *> ExistingClauses;1164  SemaOpenACC::OpenACCParsedClause &ParsedClause;1165  OpenACCClause *NewClause = nullptr;1166 1167public:1168  OpenACCDeclClauseInstantiator(Sema &S,1169                                const MultiLevelTemplateArgumentList &MLTAL,1170                                ArrayRef<OpenACCClause *> ExistingClauses,1171                                SemaOpenACC::OpenACCParsedClause &ParsedClause)1172      : SemaRef(S), MLTAL(MLTAL), ExistingClauses(ExistingClauses),1173        ParsedClause(ParsedClause) {}1174 1175  OpenACCClause *CreatedClause() { return NewClause; }1176#define VISIT_CLAUSE(CLAUSE_NAME)                                              \1177  void Visit##CLAUSE_NAME##Clause(const OpenACC##CLAUSE_NAME##Clause &Clause);1178#include "clang/Basic/OpenACCClauses.def"1179 1180  llvm::SmallVector<Expr *> VisitVarList(ArrayRef<Expr *> VarList) {1181    llvm::SmallVector<Expr *> InstantiatedVarList;1182    for (Expr *CurVar : VarList) {1183      ExprResult Res = SemaRef.SubstExpr(CurVar, MLTAL);1184 1185      if (!Res.isUsable())1186        continue;1187 1188      Res = SemaRef.OpenACC().ActOnVar(ParsedClause.getDirectiveKind(),1189                                       ParsedClause.getClauseKind(), Res.get());1190 1191      if (Res.isUsable())1192        InstantiatedVarList.push_back(Res.get());1193    }1194    return InstantiatedVarList;1195  }1196};1197 1198#define CLAUSE_NOT_ON_DECLS(CLAUSE_NAME)                                       \1199  void OpenACCDeclClauseInstantiator::Visit##CLAUSE_NAME##Clause(              \1200      const OpenACC##CLAUSE_NAME##Clause &) {                                  \1201    llvm_unreachable("Clause type invalid on declaration construct, or "       \1202                     "instantiation not implemented");                         \1203  }1204 1205CLAUSE_NOT_ON_DECLS(Auto)1206CLAUSE_NOT_ON_DECLS(Async)1207CLAUSE_NOT_ON_DECLS(Attach)1208CLAUSE_NOT_ON_DECLS(Collapse)1209CLAUSE_NOT_ON_DECLS(Default)1210CLAUSE_NOT_ON_DECLS(DefaultAsync)1211CLAUSE_NOT_ON_DECLS(Delete)1212CLAUSE_NOT_ON_DECLS(Detach)1213CLAUSE_NOT_ON_DECLS(Device)1214CLAUSE_NOT_ON_DECLS(DeviceNum)1215CLAUSE_NOT_ON_DECLS(Finalize)1216CLAUSE_NOT_ON_DECLS(FirstPrivate)1217CLAUSE_NOT_ON_DECLS(Host)1218CLAUSE_NOT_ON_DECLS(If)1219CLAUSE_NOT_ON_DECLS(IfPresent)1220CLAUSE_NOT_ON_DECLS(Independent)1221CLAUSE_NOT_ON_DECLS(NoCreate)1222CLAUSE_NOT_ON_DECLS(NumGangs)1223CLAUSE_NOT_ON_DECLS(NumWorkers)1224CLAUSE_NOT_ON_DECLS(Private)1225CLAUSE_NOT_ON_DECLS(Reduction)1226CLAUSE_NOT_ON_DECLS(Self)1227CLAUSE_NOT_ON_DECLS(Tile)1228CLAUSE_NOT_ON_DECLS(UseDevice)1229CLAUSE_NOT_ON_DECLS(VectorLength)1230CLAUSE_NOT_ON_DECLS(Wait)1231#undef CLAUSE_NOT_ON_DECLS1232 1233void OpenACCDeclClauseInstantiator::VisitGangClause(1234    const OpenACCGangClause &C) {1235  llvm::SmallVector<OpenACCGangKind> TransformedGangKinds;1236  llvm::SmallVector<Expr *> TransformedIntExprs;1237  assert(C.getNumExprs() <= 1 &&1238         "Only 1 expression allowed on gang clause in routine");1239 1240  if (C.getNumExprs() > 0) {1241    assert(C.getExpr(0).first == OpenACCGangKind::Dim &&1242           "Only dim allowed on routine");1243    ExprResult ER =1244        SemaRef.SubstExpr(const_cast<Expr *>(C.getExpr(0).second), MLTAL);1245    if (ER.isUsable()) {1246      ER = SemaRef.OpenACC().CheckGangExpr(ExistingClauses,1247                                           ParsedClause.getDirectiveKind(),1248                                           C.getExpr(0).first, ER.get());1249      if (ER.isUsable()) {1250        TransformedGangKinds.push_back(OpenACCGangKind::Dim);1251        TransformedIntExprs.push_back(ER.get());1252      }1253    }1254  }1255 1256  NewClause = SemaRef.OpenACC().CheckGangClause(1257      ParsedClause.getDirectiveKind(), ExistingClauses,1258      ParsedClause.getBeginLoc(), ParsedClause.getLParenLoc(),1259      TransformedGangKinds, TransformedIntExprs, ParsedClause.getEndLoc());1260}1261 1262void OpenACCDeclClauseInstantiator::VisitSeqClause(const OpenACCSeqClause &C) {1263  NewClause = OpenACCSeqClause::Create(SemaRef.getASTContext(),1264                                       ParsedClause.getBeginLoc(),1265                                       ParsedClause.getEndLoc());1266}1267void OpenACCDeclClauseInstantiator::VisitNoHostClause(1268    const OpenACCNoHostClause &C) {1269  NewClause = OpenACCNoHostClause::Create(SemaRef.getASTContext(),1270                                          ParsedClause.getBeginLoc(),1271                                          ParsedClause.getEndLoc());1272}1273 1274void OpenACCDeclClauseInstantiator::VisitDeviceTypeClause(1275    const OpenACCDeviceTypeClause &C) {1276  // Nothing to transform here, just create a new version of 'C'.1277  NewClause = OpenACCDeviceTypeClause::Create(1278      SemaRef.getASTContext(), C.getClauseKind(), ParsedClause.getBeginLoc(),1279      ParsedClause.getLParenLoc(), C.getArchitectures(),1280      ParsedClause.getEndLoc());1281}1282 1283void OpenACCDeclClauseInstantiator::VisitWorkerClause(1284    const OpenACCWorkerClause &C) {1285  assert(!C.hasIntExpr() && "Int Expr not allowed on routine 'worker' clause");1286  NewClause = OpenACCWorkerClause::Create(SemaRef.getASTContext(),1287                                          ParsedClause.getBeginLoc(), {},1288                                          nullptr, ParsedClause.getEndLoc());1289}1290 1291void OpenACCDeclClauseInstantiator::VisitVectorClause(1292    const OpenACCVectorClause &C) {1293  assert(!C.hasIntExpr() && "Int Expr not allowed on routine 'vector' clause");1294  NewClause = OpenACCVectorClause::Create(SemaRef.getASTContext(),1295                                          ParsedClause.getBeginLoc(), {},1296                                          nullptr, ParsedClause.getEndLoc());1297}1298 1299void OpenACCDeclClauseInstantiator::VisitCopyClause(1300    const OpenACCCopyClause &C) {1301  ParsedClause.setVarListDetails(VisitVarList(C.getVarList()),1302                                 C.getModifierList());1303  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause, C.getModifierList()))1304    return;1305  NewClause = OpenACCCopyClause::Create(1306      SemaRef.getASTContext(), ParsedClause.getClauseKind(),1307      ParsedClause.getBeginLoc(), ParsedClause.getLParenLoc(),1308      ParsedClause.getModifierList(), ParsedClause.getVarList(),1309      ParsedClause.getEndLoc());1310}1311 1312void OpenACCDeclClauseInstantiator::VisitLinkClause(1313    const OpenACCLinkClause &C) {1314  ParsedClause.setVarListDetails(1315      SemaRef.OpenACC().CheckLinkClauseVarList(VisitVarList(C.getVarList())),1316      OpenACCModifierKind::Invalid);1317 1318  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause,1319                                           OpenACCModifierKind::Invalid))1320    return;1321 1322  NewClause = OpenACCLinkClause::Create(1323      SemaRef.getASTContext(), ParsedClause.getBeginLoc(),1324      ParsedClause.getLParenLoc(), ParsedClause.getVarList(),1325      ParsedClause.getEndLoc());1326}1327 1328void OpenACCDeclClauseInstantiator::VisitDeviceResidentClause(1329    const OpenACCDeviceResidentClause &C) {1330  ParsedClause.setVarListDetails(VisitVarList(C.getVarList()),1331                                 OpenACCModifierKind::Invalid);1332  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause,1333                                           OpenACCModifierKind::Invalid))1334    return;1335  NewClause = OpenACCDeviceResidentClause::Create(1336      SemaRef.getASTContext(), ParsedClause.getBeginLoc(),1337      ParsedClause.getLParenLoc(), ParsedClause.getVarList(),1338      ParsedClause.getEndLoc());1339}1340 1341void OpenACCDeclClauseInstantiator::VisitCopyInClause(1342    const OpenACCCopyInClause &C) {1343  ParsedClause.setVarListDetails(VisitVarList(C.getVarList()),1344                                 C.getModifierList());1345 1346  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause, C.getModifierList()))1347    return;1348  NewClause = OpenACCCopyInClause::Create(1349      SemaRef.getASTContext(), ParsedClause.getClauseKind(),1350      ParsedClause.getBeginLoc(), ParsedClause.getLParenLoc(),1351      ParsedClause.getModifierList(), ParsedClause.getVarList(),1352      ParsedClause.getEndLoc());1353}1354void OpenACCDeclClauseInstantiator::VisitCopyOutClause(1355    const OpenACCCopyOutClause &C) {1356  ParsedClause.setVarListDetails(VisitVarList(C.getVarList()),1357                                 C.getModifierList());1358 1359  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause, C.getModifierList()))1360    return;1361  NewClause = OpenACCCopyOutClause::Create(1362      SemaRef.getASTContext(), ParsedClause.getClauseKind(),1363      ParsedClause.getBeginLoc(), ParsedClause.getLParenLoc(),1364      ParsedClause.getModifierList(), ParsedClause.getVarList(),1365      ParsedClause.getEndLoc());1366}1367void OpenACCDeclClauseInstantiator::VisitCreateClause(1368    const OpenACCCreateClause &C) {1369  ParsedClause.setVarListDetails(VisitVarList(C.getVarList()),1370                                 C.getModifierList());1371 1372  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause, C.getModifierList()))1373    return;1374  NewClause = OpenACCCreateClause::Create(1375      SemaRef.getASTContext(), ParsedClause.getClauseKind(),1376      ParsedClause.getBeginLoc(), ParsedClause.getLParenLoc(),1377      ParsedClause.getModifierList(), ParsedClause.getVarList(),1378      ParsedClause.getEndLoc());1379}1380void OpenACCDeclClauseInstantiator::VisitPresentClause(1381    const OpenACCPresentClause &C) {1382  ParsedClause.setVarListDetails(VisitVarList(C.getVarList()),1383                                 OpenACCModifierKind::Invalid);1384  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause,1385                                           OpenACCModifierKind::Invalid))1386    return;1387  NewClause = OpenACCPresentClause::Create(1388      SemaRef.getASTContext(), ParsedClause.getBeginLoc(),1389      ParsedClause.getLParenLoc(), ParsedClause.getVarList(),1390      ParsedClause.getEndLoc());1391}1392void OpenACCDeclClauseInstantiator::VisitDevicePtrClause(1393    const OpenACCDevicePtrClause &C) {1394  llvm::SmallVector<Expr *> VarList = VisitVarList(C.getVarList());1395  // Ensure each var is a pointer type.1396  llvm::erase_if(VarList, [&](Expr *E) {1397    return SemaRef.OpenACC().CheckVarIsPointerType(OpenACCClauseKind::DevicePtr,1398                                                   E);1399  });1400  ParsedClause.setVarListDetails(VarList, OpenACCModifierKind::Invalid);1401  if (SemaRef.OpenACC().CheckDeclareClause(ParsedClause,1402                                           OpenACCModifierKind::Invalid))1403    return;1404  NewClause = OpenACCDevicePtrClause::Create(1405      SemaRef.getASTContext(), ParsedClause.getBeginLoc(),1406      ParsedClause.getLParenLoc(), ParsedClause.getVarList(),1407      ParsedClause.getEndLoc());1408}1409 1410void OpenACCDeclClauseInstantiator::VisitBindClause(1411    const OpenACCBindClause &C) {1412  // Nothing to instantiate, we support only string literal or identifier.1413  if (C.isStringArgument())1414    NewClause = OpenACCBindClause::Create(1415        SemaRef.getASTContext(), ParsedClause.getBeginLoc(),1416        ParsedClause.getLParenLoc(), C.getStringArgument(),1417        ParsedClause.getEndLoc());1418  else1419    NewClause = OpenACCBindClause::Create(1420        SemaRef.getASTContext(), ParsedClause.getBeginLoc(),1421        ParsedClause.getLParenLoc(), C.getIdentifierArgument(),1422        ParsedClause.getEndLoc());1423}1424 1425llvm::SmallVector<OpenACCClause *> InstantiateOpenACCClauseList(1426    Sema &S, const MultiLevelTemplateArgumentList &MLTAL,1427    OpenACCDirectiveKind DK, ArrayRef<const OpenACCClause *> ClauseList) {1428  llvm::SmallVector<OpenACCClause *> TransformedClauses;1429 1430  for (const auto *Clause : ClauseList) {1431    SemaOpenACC::OpenACCParsedClause ParsedClause(DK, Clause->getClauseKind(),1432                                                  Clause->getBeginLoc());1433    ParsedClause.setEndLoc(Clause->getEndLoc());1434    if (const auto *WithParms = dyn_cast<OpenACCClauseWithParams>(Clause))1435      ParsedClause.setLParenLoc(WithParms->getLParenLoc());1436 1437    OpenACCDeclClauseInstantiator Instantiator{S, MLTAL, TransformedClauses,1438                                               ParsedClause};1439    Instantiator.Visit(Clause);1440    if (Instantiator.CreatedClause())1441      TransformedClauses.push_back(Instantiator.CreatedClause());1442  }1443  return TransformedClauses;1444}1445 1446} // namespace1447 1448static void instantiateDependentOpenACCRoutineDeclAttr(1449    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,1450    const OpenACCRoutineDeclAttr *OldAttr, const Decl *OldDecl, Decl *NewDecl) {1451  OpenACCRoutineDeclAttr *A =1452      OpenACCRoutineDeclAttr::Create(S.getASTContext(), OldAttr->getLocation());1453 1454  if (!OldAttr->Clauses.empty()) {1455    llvm::SmallVector<OpenACCClause *> TransformedClauses =1456        InstantiateOpenACCClauseList(1457            S, TemplateArgs, OpenACCDirectiveKind::Routine, OldAttr->Clauses);1458    A->Clauses.assign(TransformedClauses.begin(), TransformedClauses.end());1459  }1460 1461  // We don't end up having to do any magic-static or bind checking here, since1462  // the first phase should have caught this, since we always apply to the1463  // functiondecl.1464  NewDecl->addAttr(A);1465}1466 1467Decl *TemplateDeclInstantiator::VisitOpenACCDeclareDecl(OpenACCDeclareDecl *D) {1468  SemaRef.OpenACC().ActOnConstruct(D->getDirectiveKind(), D->getBeginLoc());1469  llvm::SmallVector<OpenACCClause *> TransformedClauses =1470      InstantiateOpenACCClauseList(SemaRef, TemplateArgs, D->getDirectiveKind(),1471                                   D->clauses());1472 1473  if (SemaRef.OpenACC().ActOnStartDeclDirective(1474          D->getDirectiveKind(), D->getBeginLoc(), TransformedClauses))1475    return nullptr;1476 1477  DeclGroupRef Res = SemaRef.OpenACC().ActOnEndDeclDirective(1478      D->getDirectiveKind(), D->getBeginLoc(), D->getDirectiveLoc(), {}, {},1479      D->getEndLoc(), TransformedClauses);1480 1481  if (Res.isNull())1482    return nullptr;1483 1484  return Res.getSingleDecl();1485}1486 1487Decl *TemplateDeclInstantiator::VisitOpenACCRoutineDecl(OpenACCRoutineDecl *D) {1488  SemaRef.OpenACC().ActOnConstruct(D->getDirectiveKind(), D->getBeginLoc());1489  llvm::SmallVector<OpenACCClause *> TransformedClauses =1490      InstantiateOpenACCClauseList(SemaRef, TemplateArgs, D->getDirectiveKind(),1491                                   D->clauses());1492 1493  ExprResult FuncRef;1494  if (D->getFunctionReference()) {1495    FuncRef = SemaRef.SubstCXXIdExpr(D->getFunctionReference(), TemplateArgs);1496    if (FuncRef.isUsable())1497      FuncRef = SemaRef.OpenACC().ActOnRoutineName(FuncRef.get());1498    // We don't return early here, we leave the construct in the AST, even if1499    // the function decl is empty.1500  }1501 1502  if (SemaRef.OpenACC().ActOnStartDeclDirective(1503          D->getDirectiveKind(), D->getBeginLoc(), TransformedClauses))1504    return nullptr;1505 1506  DeclGroupRef Res = SemaRef.OpenACC().ActOnEndRoutineDeclDirective(1507      D->getBeginLoc(), D->getDirectiveLoc(), D->getLParenLoc(), FuncRef.get(),1508      D->getRParenLoc(), TransformedClauses, D->getEndLoc(), nullptr);1509 1510  if (Res.isNull())1511    return nullptr;1512 1513  return Res.getSingleDecl();1514}1515 1516Decl *1517TemplateDeclInstantiator::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {1518  NamespaceAliasDecl *Inst1519    = NamespaceAliasDecl::Create(SemaRef.Context, Owner,1520                                 D->getNamespaceLoc(),1521                                 D->getAliasLoc(),1522                                 D->getIdentifier(),1523                                 D->getQualifierLoc(),1524                                 D->getTargetNameLoc(),1525                                 D->getNamespace());1526  Owner->addDecl(Inst);1527  return Inst;1528}1529 1530Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,1531                                                           bool IsTypeAlias) {1532  bool Invalid = false;1533  TypeSourceInfo *TSI = D->getTypeSourceInfo();1534  if (TSI->getType()->isInstantiationDependentType() ||1535      TSI->getType()->isVariablyModifiedType()) {1536    TSI = SemaRef.SubstType(TSI, TemplateArgs, D->getLocation(),1537                            D->getDeclName());1538    if (!TSI) {1539      Invalid = true;1540      TSI = SemaRef.Context.getTrivialTypeSourceInfo(SemaRef.Context.IntTy);1541    }1542  } else {1543    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), TSI->getType());1544  }1545 1546  // HACK: 2012-10-23 g++ has a bug where it gets the value kind of ?: wrong.1547  // libstdc++ relies upon this bug in its implementation of common_type.  If we1548  // happen to be processing that implementation, fake up the g++ ?:1549  // semantics. See LWG issue 2141 for more information on the bug.  The bugs1550  // are fixed in g++ and libstdc++ 4.9.0 (2014-04-22).1551  if (SemaRef.getPreprocessor().NeedsStdLibCxxWorkaroundBefore(2014'04'22)) {1552    const DecltypeType *DT = TSI->getType()->getAs<DecltypeType>();1553    CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D->getDeclContext());1554    if (DT && RD && isa<ConditionalOperator>(DT->getUnderlyingExpr()) &&1555        DT->isReferenceType() &&1556        RD->getEnclosingNamespaceContext() == SemaRef.getStdNamespace() &&1557        RD->getIdentifier() && RD->getIdentifier()->isStr("common_type") &&1558        D->getIdentifier() && D->getIdentifier()->isStr("type") &&1559        SemaRef.getSourceManager().isInSystemHeader(D->getBeginLoc()))1560      // Fold it to the (non-reference) type which g++ would have produced.1561      TSI = SemaRef.Context.getTrivialTypeSourceInfo(1562          TSI->getType().getNonReferenceType());1563  }1564 1565  // Create the new typedef1566  TypedefNameDecl *Typedef;1567  if (IsTypeAlias)1568    Typedef = TypeAliasDecl::Create(SemaRef.Context, Owner, D->getBeginLoc(),1569                                    D->getLocation(), D->getIdentifier(), TSI);1570  else1571    Typedef = TypedefDecl::Create(SemaRef.Context, Owner, D->getBeginLoc(),1572                                  D->getLocation(), D->getIdentifier(), TSI);1573  if (Invalid)1574    Typedef->setInvalidDecl();1575 1576  // If the old typedef was the name for linkage purposes of an anonymous1577  // tag decl, re-establish that relationship for the new typedef.1578  if (const TagType *oldTagType = D->getUnderlyingType()->getAs<TagType>()) {1579    TagDecl *oldTag = oldTagType->getDecl();1580    if (oldTag->getTypedefNameForAnonDecl() == D && !Invalid) {1581      TagDecl *newTag = TSI->getType()->castAs<TagType>()->getDecl();1582      assert(!newTag->hasNameForLinkage());1583      newTag->setTypedefNameForAnonDecl(Typedef);1584    }1585  }1586 1587  if (TypedefNameDecl *Prev = getPreviousDeclForInstantiation(D)) {1588    NamedDecl *InstPrev = SemaRef.FindInstantiatedDecl(D->getLocation(), Prev,1589                                                       TemplateArgs);1590    if (!InstPrev)1591      return nullptr;1592 1593    TypedefNameDecl *InstPrevTypedef = cast<TypedefNameDecl>(InstPrev);1594 1595    // If the typedef types are not identical, reject them.1596    SemaRef.isIncompatibleTypedef(InstPrevTypedef, Typedef);1597 1598    Typedef->setPreviousDecl(InstPrevTypedef);1599  }1600 1601  SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);1602 1603  if (D->getUnderlyingType()->getAs<DependentNameType>())1604    SemaRef.inferGslPointerAttribute(Typedef);1605 1606  Typedef->setAccess(D->getAccess());1607  Typedef->setReferenced(D->isReferenced());1608 1609  return Typedef;1610}1611 1612Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {1613  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/false);1614  if (Typedef)1615    Owner->addDecl(Typedef);1616  return Typedef;1617}1618 1619Decl *TemplateDeclInstantiator::VisitTypeAliasDecl(TypeAliasDecl *D) {1620  Decl *Typedef = InstantiateTypedefNameDecl(D, /*IsTypeAlias=*/true);1621  if (Typedef)1622    Owner->addDecl(Typedef);1623  return Typedef;1624}1625 1626Decl *TemplateDeclInstantiator::InstantiateTypeAliasTemplateDecl(1627    TypeAliasTemplateDecl *D) {1628  // Create a local instantiation scope for this type alias template, which1629  // will contain the instantiations of the template parameters.1630  LocalInstantiationScope Scope(SemaRef);1631 1632  TemplateParameterList *TempParams = D->getTemplateParameters();1633  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);1634  if (!InstParams)1635    return nullptr;1636 1637  // FIXME: This is a hack for instantiating lambdas in the pattern of the1638  // alias. We are not really instantiating the alias at its template level,1639  // that only happens in CheckTemplateId, this is only for outer templates1640  // which contain it. In getTemplateInstantiationArgs, the template arguments1641  // used here would be used for collating the template arguments needed to1642  // instantiate the lambda. Pass an empty argument list, so this workaround1643  // doesn't get confused if there is an outer alias being instantiated.1644  Sema::InstantiatingTemplate InstTemplate(SemaRef, D->getBeginLoc(), D,1645                                           ArrayRef<TemplateArgument>());1646  if (InstTemplate.isInvalid())1647    return nullptr;1648 1649  TypeAliasDecl *Pattern = D->getTemplatedDecl();1650  TypeAliasTemplateDecl *PrevAliasTemplate = nullptr;1651  if (getPreviousDeclForInstantiation<TypedefNameDecl>(Pattern)) {1652    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());1653    if (!Found.empty()) {1654      PrevAliasTemplate = dyn_cast<TypeAliasTemplateDecl>(Found.front());1655    }1656  }1657 1658  TypeAliasDecl *AliasInst = cast_or_null<TypeAliasDecl>(1659    InstantiateTypedefNameDecl(Pattern, /*IsTypeAlias=*/true));1660  if (!AliasInst)1661    return nullptr;1662 1663  TypeAliasTemplateDecl *Inst1664    = TypeAliasTemplateDecl::Create(SemaRef.Context, Owner, D->getLocation(),1665                                    D->getDeclName(), InstParams, AliasInst);1666  AliasInst->setDescribedAliasTemplate(Inst);1667  if (PrevAliasTemplate)1668    Inst->setPreviousDecl(PrevAliasTemplate);1669 1670  Inst->setAccess(D->getAccess());1671 1672  if (!PrevAliasTemplate)1673    Inst->setInstantiatedFromMemberTemplate(D);1674 1675  return Inst;1676}1677 1678Decl *1679TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {1680  Decl *Inst = InstantiateTypeAliasTemplateDecl(D);1681  if (Inst)1682    Owner->addDecl(Inst);1683 1684  return Inst;1685}1686 1687Decl *TemplateDeclInstantiator::VisitBindingDecl(BindingDecl *D) {1688  auto *NewBD = BindingDecl::Create(SemaRef.Context, Owner, D->getLocation(),1689                                    D->getIdentifier(), D->getType());1690  NewBD->setReferenced(D->isReferenced());1691  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewBD);1692 1693  return NewBD;1694}1695 1696Decl *TemplateDeclInstantiator::VisitDecompositionDecl(DecompositionDecl *D) {1697  // Transform the bindings first.1698  // The transformed DD will have all of the concrete BindingDecls.1699  SmallVector<BindingDecl*, 16> NewBindings;1700  BindingDecl *OldBindingPack = nullptr;1701  for (auto *OldBD : D->bindings()) {1702    Expr *BindingExpr = OldBD->getBinding();1703    if (isa_and_present<FunctionParmPackExpr>(BindingExpr)) {1704      // We have a resolved pack.1705      assert(!OldBindingPack && "no more than one pack is allowed");1706      OldBindingPack = OldBD;1707    }1708    NewBindings.push_back(cast<BindingDecl>(VisitBindingDecl(OldBD)));1709  }1710  ArrayRef<BindingDecl*> NewBindingArray = NewBindings;1711 1712  auto *NewDD = cast_if_present<DecompositionDecl>(1713      VisitVarDecl(D, /*InstantiatingVarTemplate=*/false, &NewBindingArray));1714 1715  if (!NewDD || NewDD->isInvalidDecl()) {1716    for (auto *NewBD : NewBindings)1717      NewBD->setInvalidDecl();1718  } else if (OldBindingPack) {1719    // Mark the bindings in the pack as instantiated.1720    auto Bindings = NewDD->bindings();1721    BindingDecl *NewBindingPack = *llvm::find_if(1722        Bindings, [](BindingDecl *D) -> bool { return D->isParameterPack(); });1723    assert(NewBindingPack != nullptr && "new bindings should also have a pack");1724    llvm::ArrayRef<BindingDecl *> OldDecls =1725        OldBindingPack->getBindingPackDecls();1726    llvm::ArrayRef<BindingDecl *> NewDecls =1727        NewBindingPack->getBindingPackDecls();1728    assert(OldDecls.size() == NewDecls.size());1729    for (unsigned I = 0; I < OldDecls.size(); I++)1730      SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldDecls[I],1731                                                           NewDecls[I]);1732  }1733 1734  return NewDD;1735}1736 1737Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {1738  return VisitVarDecl(D, /*InstantiatingVarTemplate=*/false);1739}1740 1741Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D,1742                                             bool InstantiatingVarTemplate,1743                                             ArrayRef<BindingDecl*> *Bindings) {1744 1745  // Do substitution on the type of the declaration1746  TypeSourceInfo *TSI = SemaRef.SubstType(1747      D->getTypeSourceInfo(), TemplateArgs, D->getTypeSpecStartLoc(),1748      D->getDeclName(), /*AllowDeducedTST*/ true);1749  if (!TSI)1750    return nullptr;1751 1752  if (TSI->getType()->isFunctionType()) {1753    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)1754        << D->isStaticDataMember() << TSI->getType();1755    return nullptr;1756  }1757 1758  DeclContext *DC = Owner;1759  if (D->isLocalExternDecl())1760    SemaRef.adjustContextForLocalExternDecl(DC);1761 1762  // Build the instantiated declaration.1763  VarDecl *Var;1764  if (Bindings)1765    Var = DecompositionDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),1766                                    D->getLocation(), TSI->getType(), TSI,1767                                    D->getStorageClass(), *Bindings);1768  else1769    Var = VarDecl::Create(SemaRef.Context, DC, D->getInnerLocStart(),1770                          D->getLocation(), D->getIdentifier(), TSI->getType(),1771                          TSI, D->getStorageClass());1772 1773  // In ARC, infer 'retaining' for variables of retainable type.1774  if (SemaRef.getLangOpts().ObjCAutoRefCount &&1775      SemaRef.ObjC().inferObjCARCLifetime(Var))1776    Var->setInvalidDecl();1777 1778  if (SemaRef.getLangOpts().OpenCL)1779    SemaRef.deduceOpenCLAddressSpace(Var);1780 1781  // Substitute the nested name specifier, if any.1782  if (SubstQualifier(D, Var))1783    return nullptr;1784 1785  SemaRef.BuildVariableInstantiation(Var, D, TemplateArgs, LateAttrs, Owner,1786                                     StartingScope, InstantiatingVarTemplate);1787  if (D->isNRVOVariable() && !Var->isInvalidDecl()) {1788    QualType RT;1789    if (auto *F = dyn_cast<FunctionDecl>(DC))1790      RT = F->getReturnType();1791    else if (isa<BlockDecl>(DC))1792      RT = cast<FunctionType>(SemaRef.getCurBlock()->FunctionType)1793               ->getReturnType();1794    else1795      llvm_unreachable("Unknown context type");1796 1797    // This is the last chance we have of checking copy elision eligibility1798    // for functions in dependent contexts. The sema actions for building1799    // the return statement during template instantiation will have no effect1800    // regarding copy elision, since NRVO propagation runs on the scope exit1801    // actions, and these are not run on instantiation.1802    // This might run through some VarDecls which were returned from non-taken1803    // 'if constexpr' branches, and these will end up being constructed on the1804    // return slot even if they will never be returned, as a sort of accidental1805    // 'optimization'. Notably, functions with 'auto' return types won't have it1806    // deduced by this point. Coupled with the limitation described1807    // previously, this makes it very hard to support copy elision for these.1808    Sema::NamedReturnInfo Info = SemaRef.getNamedReturnInfo(Var);1809    bool NRVO = SemaRef.getCopyElisionCandidate(Info, RT) != nullptr;1810    Var->setNRVOVariable(NRVO);1811  }1812 1813  Var->setImplicit(D->isImplicit());1814 1815  if (Var->isStaticLocal())1816    SemaRef.CheckStaticLocalForDllExport(Var);1817 1818  if (Var->getTLSKind())1819    SemaRef.CheckThreadLocalForLargeAlignment(Var);1820 1821  if (SemaRef.getLangOpts().OpenACC)1822    SemaRef.OpenACC().ActOnVariableDeclarator(Var);1823 1824  return Var;1825}1826 1827Decl *TemplateDeclInstantiator::VisitAccessSpecDecl(AccessSpecDecl *D) {1828  AccessSpecDecl* AD1829    = AccessSpecDecl::Create(SemaRef.Context, D->getAccess(), Owner,1830                             D->getAccessSpecifierLoc(), D->getColonLoc());1831  Owner->addHiddenDecl(AD);1832  return AD;1833}1834 1835Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {1836  bool Invalid = false;1837  TypeSourceInfo *TSI = D->getTypeSourceInfo();1838  if (TSI->getType()->isInstantiationDependentType() ||1839      TSI->getType()->isVariablyModifiedType()) {1840    TSI = SemaRef.SubstType(TSI, TemplateArgs, D->getLocation(),1841                            D->getDeclName());1842    if (!TSI) {1843      TSI = D->getTypeSourceInfo();1844      Invalid = true;1845    } else if (TSI->getType()->isFunctionType()) {1846      // C++ [temp.arg.type]p3:1847      //   If a declaration acquires a function type through a type1848      //   dependent on a template-parameter and this causes a1849      //   declaration that does not use the syntactic form of a1850      //   function declarator to have function type, the program is1851      //   ill-formed.1852      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)1853          << TSI->getType();1854      Invalid = true;1855    }1856  } else {1857    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), TSI->getType());1858  }1859 1860  Expr *BitWidth = D->getBitWidth();1861  if (Invalid)1862    BitWidth = nullptr;1863  else if (BitWidth) {1864    // The bit-width expression is a constant expression.1865    EnterExpressionEvaluationContext Unevaluated(1866        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);1867 1868    ExprResult InstantiatedBitWidth1869      = SemaRef.SubstExpr(BitWidth, TemplateArgs);1870    if (InstantiatedBitWidth.isInvalid()) {1871      Invalid = true;1872      BitWidth = nullptr;1873    } else1874      BitWidth = InstantiatedBitWidth.getAs<Expr>();1875  }1876 1877  FieldDecl *Field = SemaRef.CheckFieldDecl(1878      D->getDeclName(), TSI->getType(), TSI, cast<RecordDecl>(Owner),1879      D->getLocation(), D->isMutable(), BitWidth, D->getInClassInitStyle(),1880      D->getInnerLocStart(), D->getAccess(), nullptr);1881  if (!Field) {1882    cast<Decl>(Owner)->setInvalidDecl();1883    return nullptr;1884  }1885 1886  SemaRef.InstantiateAttrs(TemplateArgs, D, Field, LateAttrs, StartingScope);1887 1888  if (Field->hasAttrs())1889    SemaRef.CheckAlignasUnderalignment(Field);1890 1891  if (Invalid)1892    Field->setInvalidDecl();1893 1894  if (!Field->getDeclName() || Field->isPlaceholderVar(SemaRef.getLangOpts())) {1895    // Keep track of where this decl came from.1896    SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);1897  }1898  if (CXXRecordDecl *Parent= dyn_cast<CXXRecordDecl>(Field->getDeclContext())) {1899    if (Parent->isAnonymousStructOrUnion() &&1900        Parent->getRedeclContext()->isFunctionOrMethod())1901      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Field);1902  }1903 1904  Field->setImplicit(D->isImplicit());1905  Field->setAccess(D->getAccess());1906  Owner->addDecl(Field);1907 1908  return Field;1909}1910 1911Decl *TemplateDeclInstantiator::VisitMSPropertyDecl(MSPropertyDecl *D) {1912  bool Invalid = false;1913  TypeSourceInfo *TSI = D->getTypeSourceInfo();1914 1915  if (TSI->getType()->isVariablyModifiedType()) {1916    SemaRef.Diag(D->getLocation(), diag::err_property_is_variably_modified)1917      << D;1918    Invalid = true;1919  } else if (TSI->getType()->isInstantiationDependentType()) {1920    TSI = SemaRef.SubstType(TSI, TemplateArgs, D->getLocation(),1921                            D->getDeclName());1922    if (!TSI) {1923      TSI = D->getTypeSourceInfo();1924      Invalid = true;1925    } else if (TSI->getType()->isFunctionType()) {1926      // C++ [temp.arg.type]p3:1927      //   If a declaration acquires a function type through a type1928      //   dependent on a template-parameter and this causes a1929      //   declaration that does not use the syntactic form of a1930      //   function declarator to have function type, the program is1931      //   ill-formed.1932      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)1933          << TSI->getType();1934      Invalid = true;1935    }1936  } else {1937    SemaRef.MarkDeclarationsReferencedInType(D->getLocation(), TSI->getType());1938  }1939 1940  MSPropertyDecl *Property = MSPropertyDecl::Create(1941      SemaRef.Context, Owner, D->getLocation(), D->getDeclName(),1942      TSI->getType(), TSI, D->getBeginLoc(), D->getGetterId(),1943      D->getSetterId());1944 1945  SemaRef.InstantiateAttrs(TemplateArgs, D, Property, LateAttrs,1946                           StartingScope);1947 1948  if (Invalid)1949    Property->setInvalidDecl();1950 1951  Property->setAccess(D->getAccess());1952  Owner->addDecl(Property);1953 1954  return Property;1955}1956 1957Decl *TemplateDeclInstantiator::VisitIndirectFieldDecl(IndirectFieldDecl *D) {1958  NamedDecl **NamedChain =1959    new (SemaRef.Context)NamedDecl*[D->getChainingSize()];1960 1961  int i = 0;1962  for (auto *PI : D->chain()) {1963    NamedDecl *Next = SemaRef.FindInstantiatedDecl(D->getLocation(), PI,1964                                              TemplateArgs);1965    if (!Next)1966      return nullptr;1967 1968    NamedChain[i++] = Next;1969  }1970 1971  QualType T = cast<FieldDecl>(NamedChain[i-1])->getType();1972  IndirectFieldDecl *IndirectField = IndirectFieldDecl::Create(1973      SemaRef.Context, Owner, D->getLocation(), D->getIdentifier(), T,1974      {NamedChain, D->getChainingSize()});1975 1976  for (const auto *Attr : D->attrs())1977    IndirectField->addAttr(Attr->clone(SemaRef.Context));1978 1979  IndirectField->setImplicit(D->isImplicit());1980  IndirectField->setAccess(D->getAccess());1981  Owner->addDecl(IndirectField);1982  return IndirectField;1983}1984 1985Decl *TemplateDeclInstantiator::VisitFriendDecl(FriendDecl *D) {1986  // Handle friend type expressions by simply substituting template1987  // parameters into the pattern type and checking the result.1988  if (TypeSourceInfo *Ty = D->getFriendType()) {1989    TypeSourceInfo *InstTy;1990    // If this is an unsupported friend, don't bother substituting template1991    // arguments into it. The actual type referred to won't be used by any1992    // parts of Clang, and may not be valid for instantiating. Just use the1993    // same info for the instantiated friend.1994    if (D->isUnsupportedFriend()) {1995      InstTy = Ty;1996    } else {1997      if (D->isPackExpansion()) {1998        SmallVector<UnexpandedParameterPack, 2> Unexpanded;1999        SemaRef.collectUnexpandedParameterPacks(Ty->getTypeLoc(), Unexpanded);2000        assert(!Unexpanded.empty() && "Pack expansion without packs");2001 2002        bool ShouldExpand = true;2003        bool RetainExpansion = false;2004        UnsignedOrNone NumExpansions = std::nullopt;2005        if (SemaRef.CheckParameterPacksForExpansion(2006                D->getEllipsisLoc(), D->getSourceRange(), Unexpanded,2007                TemplateArgs, /*FailOnPackProducingTemplates=*/true,2008                ShouldExpand, RetainExpansion, NumExpansions))2009          return nullptr;2010 2011        assert(!RetainExpansion &&2012               "should never retain an expansion for a variadic friend decl");2013 2014        if (ShouldExpand) {2015          SmallVector<FriendDecl *> Decls;2016          for (unsigned I = 0; I != *NumExpansions; I++) {2017            Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, I);2018            TypeSourceInfo *TSI = SemaRef.SubstType(2019                Ty, TemplateArgs, D->getEllipsisLoc(), DeclarationName());2020            if (!TSI)2021              return nullptr;2022 2023            auto FD =2024                FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),2025                                   TSI, D->getFriendLoc());2026 2027            FD->setAccess(AS_public);2028            Owner->addDecl(FD);2029            Decls.push_back(FD);2030          }2031 2032          // Just drop this node; we have no use for it anymore.2033          return nullptr;2034        }2035      }2036 2037      InstTy = SemaRef.SubstType(Ty, TemplateArgs, D->getLocation(),2038                                 DeclarationName());2039    }2040    if (!InstTy)2041      return nullptr;2042 2043    FriendDecl *FD = FriendDecl::Create(2044        SemaRef.Context, Owner, D->getLocation(), InstTy, D->getFriendLoc());2045    FD->setAccess(AS_public);2046    FD->setUnsupportedFriend(D->isUnsupportedFriend());2047    Owner->addDecl(FD);2048    return FD;2049  }2050 2051  NamedDecl *ND = D->getFriendDecl();2052  assert(ND && "friend decl must be a decl or a type!");2053 2054  // All of the Visit implementations for the various potential friend2055  // declarations have to be carefully written to work for friend2056  // objects, with the most important detail being that the target2057  // decl should almost certainly not be placed in Owner.2058  Decl *NewND = Visit(ND);2059  if (!NewND) return nullptr;2060 2061  FriendDecl *FD =2062    FriendDecl::Create(SemaRef.Context, Owner, D->getLocation(),2063                       cast<NamedDecl>(NewND), D->getFriendLoc());2064  FD->setAccess(AS_public);2065  FD->setUnsupportedFriend(D->isUnsupportedFriend());2066  Owner->addDecl(FD);2067  return FD;2068}2069 2070Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {2071  Expr *AssertExpr = D->getAssertExpr();2072 2073  // The expression in a static assertion is a constant expression.2074  EnterExpressionEvaluationContext Unevaluated(2075      SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);2076 2077  ExprResult InstantiatedAssertExpr2078    = SemaRef.SubstExpr(AssertExpr, TemplateArgs);2079  if (InstantiatedAssertExpr.isInvalid())2080    return nullptr;2081 2082  ExprResult InstantiatedMessageExpr =2083      SemaRef.SubstExpr(D->getMessage(), TemplateArgs);2084  if (InstantiatedMessageExpr.isInvalid())2085    return nullptr;2086 2087  return SemaRef.BuildStaticAssertDeclaration(2088      D->getLocation(), InstantiatedAssertExpr.get(),2089      InstantiatedMessageExpr.get(), D->getRParenLoc(), D->isFailed());2090}2091 2092Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {2093  EnumDecl *PrevDecl = nullptr;2094  if (EnumDecl *PatternPrev = getPreviousDeclForInstantiation(D)) {2095    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),2096                                                   PatternPrev,2097                                                   TemplateArgs);2098    if (!Prev) return nullptr;2099    PrevDecl = cast<EnumDecl>(Prev);2100  }2101 2102  EnumDecl *Enum =2103      EnumDecl::Create(SemaRef.Context, Owner, D->getBeginLoc(),2104                       D->getLocation(), D->getIdentifier(), PrevDecl,2105                       D->isScoped(), D->isScopedUsingClassTag(), D->isFixed());2106  if (D->isFixed()) {2107    if (TypeSourceInfo *TI = D->getIntegerTypeSourceInfo()) {2108      // If we have type source information for the underlying type, it means it2109      // has been explicitly set by the user. Perform substitution on it before2110      // moving on.2111      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();2112      TypeSourceInfo *NewTI = SemaRef.SubstType(TI, TemplateArgs, UnderlyingLoc,2113                                                DeclarationName());2114      if (!NewTI || SemaRef.CheckEnumUnderlyingType(NewTI))2115        Enum->setIntegerType(SemaRef.Context.IntTy);2116      else {2117        // If the underlying type is atomic, we need to adjust the type before2118        // continuing. See C23 6.7.3.3p5 and Sema::ActOnTag(). FIXME: same as2119        // within ActOnTag(), it would be nice to have an easy way to get a2120        // derived TypeSourceInfo which strips qualifiers including the weird2121        // ones like _Atomic where it forms a different type.2122        if (NewTI->getType()->isAtomicType())2123          Enum->setIntegerType(NewTI->getType().getAtomicUnqualifiedType());2124        else2125          Enum->setIntegerTypeSourceInfo(NewTI);2126      }2127 2128      // C++23 [conv.prom]p42129      // if integral promotion can be applied to its underlying type, a prvalue2130      // of an unscoped enumeration type whose underlying type is fixed can also2131      // be converted to a prvalue of the promoted underlying type.2132      //2133      // FIXME: that logic is already implemented in ActOnEnumBody, factor out2134      // into (Re)BuildEnumBody.2135      QualType UnderlyingType = Enum->getIntegerType();2136      Enum->setPromotionType(2137          SemaRef.Context.isPromotableIntegerType(UnderlyingType)2138              ? SemaRef.Context.getPromotedIntegerType(UnderlyingType)2139              : UnderlyingType);2140    } else {2141      assert(!D->getIntegerType()->isDependentType()2142             && "Dependent type without type source info");2143      Enum->setIntegerType(D->getIntegerType());2144    }2145  }2146 2147  SemaRef.InstantiateAttrs(TemplateArgs, D, Enum);2148 2149  Enum->setInstantiationOfMemberEnum(D, TSK_ImplicitInstantiation);2150  Enum->setAccess(D->getAccess());2151  // Forward the mangling number from the template to the instantiated decl.2152  SemaRef.Context.setManglingNumber(Enum, SemaRef.Context.getManglingNumber(D));2153  // See if the old tag was defined along with a declarator.2154  // If it did, mark the new tag as being associated with that declarator.2155  if (DeclaratorDecl *DD = SemaRef.Context.getDeclaratorForUnnamedTagDecl(D))2156    SemaRef.Context.addDeclaratorForUnnamedTagDecl(Enum, DD);2157  // See if the old tag was defined along with a typedef.2158  // If it did, mark the new tag as being associated with that typedef.2159  if (TypedefNameDecl *TND = SemaRef.Context.getTypedefNameForUnnamedTagDecl(D))2160    SemaRef.Context.addTypedefNameForUnnamedTagDecl(Enum, TND);2161  if (SubstQualifier(D, Enum)) return nullptr;2162  Owner->addDecl(Enum);2163 2164  EnumDecl *Def = D->getDefinition();2165  if (Def && Def != D) {2166    // If this is an out-of-line definition of an enum member template, check2167    // that the underlying types match in the instantiation of both2168    // declarations.2169    if (TypeSourceInfo *TI = Def->getIntegerTypeSourceInfo()) {2170      SourceLocation UnderlyingLoc = TI->getTypeLoc().getBeginLoc();2171      QualType DefnUnderlying =2172        SemaRef.SubstType(TI->getType(), TemplateArgs,2173                          UnderlyingLoc, DeclarationName());2174      SemaRef.CheckEnumRedeclaration(Def->getLocation(), Def->isScoped(),2175                                     DefnUnderlying, /*IsFixed=*/true, Enum);2176    }2177  }2178 2179  // C++11 [temp.inst]p1: The implicit instantiation of a class template2180  // specialization causes the implicit instantiation of the declarations, but2181  // not the definitions of scoped member enumerations.2182  //2183  // DR1484 clarifies that enumeration definitions inside a template2184  // declaration aren't considered entities that can be separately instantiated2185  // from the rest of the entity they are declared inside.2186  if (isDeclWithinFunction(D) ? D == Def : Def && !Enum->isScoped()) {2187    // Prevent redundant instantiation of the enumerator-definition if the2188    // definition has already been instantiated due to a prior2189    // opaque-enum-declaration.2190    if (PrevDecl == nullptr) {2191      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Enum);2192      InstantiateEnumDefinition(Enum, Def);2193    }2194  }2195 2196  return Enum;2197}2198 2199void TemplateDeclInstantiator::InstantiateEnumDefinition(2200    EnumDecl *Enum, EnumDecl *Pattern) {2201  Enum->startDefinition();2202 2203  // Update the location to refer to the definition.2204  Enum->setLocation(Pattern->getLocation());2205 2206  SmallVector<Decl*, 4> Enumerators;2207 2208  EnumConstantDecl *LastEnumConst = nullptr;2209  for (auto *EC : Pattern->enumerators()) {2210    // The specified value for the enumerator.2211    ExprResult Value((Expr *)nullptr);2212    if (Expr *UninstValue = EC->getInitExpr()) {2213      // The enumerator's value expression is a constant expression.2214      EnterExpressionEvaluationContext Unevaluated(2215          SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);2216 2217      Value = SemaRef.SubstExpr(UninstValue, TemplateArgs);2218    }2219 2220    // Drop the initial value and continue.2221    bool isInvalid = false;2222    if (Value.isInvalid()) {2223      Value = nullptr;2224      isInvalid = true;2225    }2226 2227    EnumConstantDecl *EnumConst2228      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,2229                                  EC->getLocation(), EC->getIdentifier(),2230                                  Value.get());2231 2232    if (isInvalid) {2233      if (EnumConst)2234        EnumConst->setInvalidDecl();2235      Enum->setInvalidDecl();2236    }2237 2238    if (EnumConst) {2239      SemaRef.InstantiateAttrs(TemplateArgs, EC, EnumConst);2240 2241      EnumConst->setAccess(Enum->getAccess());2242      Enum->addDecl(EnumConst);2243      Enumerators.push_back(EnumConst);2244      LastEnumConst = EnumConst;2245 2246      if (Pattern->getDeclContext()->isFunctionOrMethod() &&2247          !Enum->isScoped()) {2248        // If the enumeration is within a function or method, record the enum2249        // constant as a local.2250        SemaRef.CurrentInstantiationScope->InstantiatedLocal(EC, EnumConst);2251      }2252    }2253  }2254 2255  SemaRef.ActOnEnumBody(Enum->getLocation(), Enum->getBraceRange(), Enum,2256                        Enumerators, nullptr, ParsedAttributesView());2257}2258 2259Decl *TemplateDeclInstantiator::VisitEnumConstantDecl(EnumConstantDecl *D) {2260  llvm_unreachable("EnumConstantDecls can only occur within EnumDecls.");2261}2262 2263Decl *2264TemplateDeclInstantiator::VisitBuiltinTemplateDecl(BuiltinTemplateDecl *D) {2265  llvm_unreachable("BuiltinTemplateDecls cannot be instantiated.");2266}2267 2268Decl *TemplateDeclInstantiator::VisitClassTemplateDecl(ClassTemplateDecl *D) {2269  bool isFriend = (D->getFriendObjectKind() != Decl::FOK_None);2270 2271  // Create a local instantiation scope for this class template, which2272  // will contain the instantiations of the template parameters.2273  LocalInstantiationScope Scope(SemaRef);2274  TemplateParameterList *TempParams = D->getTemplateParameters();2275  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);2276  if (!InstParams)2277    return nullptr;2278 2279  CXXRecordDecl *Pattern = D->getTemplatedDecl();2280 2281  // Instantiate the qualifier.  We have to do this first in case2282  // we're a friend declaration, because if we are then we need to put2283  // the new declaration in the appropriate context.2284  NestedNameSpecifierLoc QualifierLoc = Pattern->getQualifierLoc();2285  if (QualifierLoc) {2286    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,2287                                                       TemplateArgs);2288    if (!QualifierLoc)2289      return nullptr;2290  }2291 2292  CXXRecordDecl *PrevDecl = nullptr;2293  ClassTemplateDecl *PrevClassTemplate = nullptr;2294 2295  if (!isFriend && getPreviousDeclForInstantiation(Pattern)) {2296    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());2297    if (!Found.empty()) {2298      PrevClassTemplate = dyn_cast<ClassTemplateDecl>(Found.front());2299      if (PrevClassTemplate)2300        PrevDecl = PrevClassTemplate->getTemplatedDecl();2301    }2302  }2303 2304  // If this isn't a friend, then it's a member template, in which2305  // case we just want to build the instantiation in the2306  // specialization.  If it is a friend, we want to build it in2307  // the appropriate context.2308  DeclContext *DC = Owner;2309  if (isFriend) {2310    if (QualifierLoc) {2311      CXXScopeSpec SS;2312      SS.Adopt(QualifierLoc);2313      DC = SemaRef.computeDeclContext(SS);2314      if (!DC) return nullptr;2315    } else {2316      DC = SemaRef.FindInstantiatedContext(Pattern->getLocation(),2317                                           Pattern->getDeclContext(),2318                                           TemplateArgs);2319    }2320 2321    // Look for a previous declaration of the template in the owning2322    // context.2323    LookupResult R(SemaRef, Pattern->getDeclName(), Pattern->getLocation(),2324                   Sema::LookupOrdinaryName,2325                   SemaRef.forRedeclarationInCurContext());2326    SemaRef.LookupQualifiedName(R, DC);2327 2328    if (R.isSingleResult()) {2329      PrevClassTemplate = R.getAsSingle<ClassTemplateDecl>();2330      if (PrevClassTemplate)2331        PrevDecl = PrevClassTemplate->getTemplatedDecl();2332    }2333 2334    if (!PrevClassTemplate && QualifierLoc) {2335      SemaRef.Diag(Pattern->getLocation(), diag::err_not_tag_in_scope)2336          << D->getTemplatedDecl()->getTagKind() << Pattern->getDeclName() << DC2337          << QualifierLoc.getSourceRange();2338      return nullptr;2339    }2340  }2341 2342  CXXRecordDecl *RecordInst = CXXRecordDecl::Create(2343      SemaRef.Context, Pattern->getTagKind(), DC, Pattern->getBeginLoc(),2344      Pattern->getLocation(), Pattern->getIdentifier(), PrevDecl);2345  if (QualifierLoc)2346    RecordInst->setQualifierInfo(QualifierLoc);2347 2348  SemaRef.InstantiateAttrsForDecl(TemplateArgs, Pattern, RecordInst, LateAttrs,2349                                                              StartingScope);2350 2351  ClassTemplateDecl *Inst2352    = ClassTemplateDecl::Create(SemaRef.Context, DC, D->getLocation(),2353                                D->getIdentifier(), InstParams, RecordInst);2354  RecordInst->setDescribedClassTemplate(Inst);2355 2356  if (isFriend) {2357    assert(!Owner->isDependentContext());2358    Inst->setLexicalDeclContext(Owner);2359    RecordInst->setLexicalDeclContext(Owner);2360    Inst->setObjectOfFriendDecl();2361 2362    if (PrevClassTemplate) {2363      Inst->setCommonPtr(PrevClassTemplate->getCommonPtr());2364      const ClassTemplateDecl *MostRecentPrevCT =2365          PrevClassTemplate->getMostRecentDecl();2366      TemplateParameterList *PrevParams =2367          MostRecentPrevCT->getTemplateParameters();2368 2369      // Make sure the parameter lists match.2370      if (!SemaRef.TemplateParameterListsAreEqual(2371              RecordInst, InstParams, MostRecentPrevCT->getTemplatedDecl(),2372              PrevParams, true, Sema::TPL_TemplateMatch))2373        return nullptr;2374 2375      // Do some additional validation, then merge default arguments2376      // from the existing declarations.2377      if (SemaRef.CheckTemplateParameterList(InstParams, PrevParams,2378                                             Sema::TPC_Other))2379        return nullptr;2380 2381      Inst->setAccess(PrevClassTemplate->getAccess());2382    } else {2383      Inst->setAccess(D->getAccess());2384    }2385 2386    Inst->setObjectOfFriendDecl();2387    // TODO: do we want to track the instantiation progeny of this2388    // friend target decl?2389  } else {2390    Inst->setAccess(D->getAccess());2391    if (!PrevClassTemplate)2392      Inst->setInstantiatedFromMemberTemplate(D);2393  }2394 2395  Inst->setPreviousDecl(PrevClassTemplate);2396 2397  // Finish handling of friends.2398  if (isFriend) {2399    DC->makeDeclVisibleInContext(Inst);2400    return Inst;2401  }2402 2403  if (D->isOutOfLine()) {2404    Inst->setLexicalDeclContext(D->getLexicalDeclContext());2405    RecordInst->setLexicalDeclContext(D->getLexicalDeclContext());2406  }2407 2408  Owner->addDecl(Inst);2409 2410  if (!PrevClassTemplate) {2411    // Queue up any out-of-line partial specializations of this member2412    // class template; the client will force their instantiation once2413    // the enclosing class has been instantiated.2414    SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs;2415    D->getPartialSpecializations(PartialSpecs);2416    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)2417      if (PartialSpecs[I]->getFirstDecl()->isOutOfLine())2418        OutOfLinePartialSpecs.push_back(std::make_pair(Inst, PartialSpecs[I]));2419  }2420 2421  return Inst;2422}2423 2424Decl *2425TemplateDeclInstantiator::VisitClassTemplatePartialSpecializationDecl(2426                                   ClassTemplatePartialSpecializationDecl *D) {2427  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();2428 2429  // Lookup the already-instantiated declaration in the instantiation2430  // of the class template and return that.2431  DeclContext::lookup_result Found2432    = Owner->lookup(ClassTemplate->getDeclName());2433  if (Found.empty())2434    return nullptr;2435 2436  ClassTemplateDecl *InstClassTemplate2437    = dyn_cast<ClassTemplateDecl>(Found.front());2438  if (!InstClassTemplate)2439    return nullptr;2440 2441  if (ClassTemplatePartialSpecializationDecl *Result2442        = InstClassTemplate->findPartialSpecInstantiatedFromMember(D))2443    return Result;2444 2445  return InstantiateClassTemplatePartialSpecialization(InstClassTemplate, D);2446}2447 2448Decl *TemplateDeclInstantiator::VisitVarTemplateDecl(VarTemplateDecl *D) {2449  assert(D->getTemplatedDecl()->isStaticDataMember() &&2450         "Only static data member templates are allowed.");2451 2452  // Create a local instantiation scope for this variable template, which2453  // will contain the instantiations of the template parameters.2454  LocalInstantiationScope Scope(SemaRef);2455  TemplateParameterList *TempParams = D->getTemplateParameters();2456  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);2457  if (!InstParams)2458    return nullptr;2459 2460  VarDecl *Pattern = D->getTemplatedDecl();2461  VarTemplateDecl *PrevVarTemplate = nullptr;2462 2463  if (getPreviousDeclForInstantiation(Pattern)) {2464    DeclContext::lookup_result Found = Owner->lookup(Pattern->getDeclName());2465    if (!Found.empty())2466      PrevVarTemplate = dyn_cast<VarTemplateDecl>(Found.front());2467  }2468 2469  VarDecl *VarInst =2470      cast_or_null<VarDecl>(VisitVarDecl(Pattern,2471                                         /*InstantiatingVarTemplate=*/true));2472  if (!VarInst) return nullptr;2473 2474  DeclContext *DC = Owner;2475 2476  VarTemplateDecl *Inst = VarTemplateDecl::Create(2477      SemaRef.Context, DC, D->getLocation(), D->getIdentifier(), InstParams,2478      VarInst);2479  VarInst->setDescribedVarTemplate(Inst);2480  Inst->setPreviousDecl(PrevVarTemplate);2481 2482  Inst->setAccess(D->getAccess());2483  if (!PrevVarTemplate)2484    Inst->setInstantiatedFromMemberTemplate(D);2485 2486  if (D->isOutOfLine()) {2487    Inst->setLexicalDeclContext(D->getLexicalDeclContext());2488    VarInst->setLexicalDeclContext(D->getLexicalDeclContext());2489  }2490 2491  Owner->addDecl(Inst);2492 2493  if (!PrevVarTemplate) {2494    // Queue up any out-of-line partial specializations of this member2495    // variable template; the client will force their instantiation once2496    // the enclosing class has been instantiated.2497    SmallVector<VarTemplatePartialSpecializationDecl *, 1> PartialSpecs;2498    D->getPartialSpecializations(PartialSpecs);2499    for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I)2500      if (PartialSpecs[I]->getFirstDecl()->isOutOfLine())2501        OutOfLineVarPartialSpecs.push_back(2502            std::make_pair(Inst, PartialSpecs[I]));2503  }2504 2505  return Inst;2506}2507 2508Decl *TemplateDeclInstantiator::VisitVarTemplatePartialSpecializationDecl(2509    VarTemplatePartialSpecializationDecl *D) {2510  assert(D->isStaticDataMember() &&2511         "Only static data member templates are allowed.");2512 2513  VarTemplateDecl *VarTemplate = D->getSpecializedTemplate();2514 2515  // Lookup the already-instantiated declaration and return that.2516  DeclContext::lookup_result Found = Owner->lookup(VarTemplate->getDeclName());2517  assert(!Found.empty() && "Instantiation found nothing?");2518 2519  VarTemplateDecl *InstVarTemplate = dyn_cast<VarTemplateDecl>(Found.front());2520  assert(InstVarTemplate && "Instantiation did not find a variable template?");2521 2522  if (VarTemplatePartialSpecializationDecl *Result =2523          InstVarTemplate->findPartialSpecInstantiatedFromMember(D))2524    return Result;2525 2526  return InstantiateVarTemplatePartialSpecialization(InstVarTemplate, D);2527}2528 2529Decl *2530TemplateDeclInstantiator::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {2531  // Create a local instantiation scope for this function template, which2532  // will contain the instantiations of the template parameters and then get2533  // merged with the local instantiation scope for the function template2534  // itself.2535  LocalInstantiationScope Scope(SemaRef);2536  Sema::ConstraintEvalRAII<TemplateDeclInstantiator> RAII(*this);2537 2538  TemplateParameterList *TempParams = D->getTemplateParameters();2539  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);2540  if (!InstParams)2541    return nullptr;2542 2543  FunctionDecl *Instantiated = nullptr;2544  if (CXXMethodDecl *DMethod = dyn_cast<CXXMethodDecl>(D->getTemplatedDecl()))2545    Instantiated = cast_or_null<FunctionDecl>(VisitCXXMethodDecl(DMethod,2546                                                                 InstParams));2547  else2548    Instantiated = cast_or_null<FunctionDecl>(VisitFunctionDecl(2549                                                          D->getTemplatedDecl(),2550                                                                InstParams));2551 2552  if (!Instantiated)2553    return nullptr;2554 2555  // Link the instantiated function template declaration to the function2556  // template from which it was instantiated.2557  FunctionTemplateDecl *InstTemplate2558    = Instantiated->getDescribedFunctionTemplate();2559  InstTemplate->setAccess(D->getAccess());2560  assert(InstTemplate &&2561         "VisitFunctionDecl/CXXMethodDecl didn't create a template!");2562 2563  bool isFriend = (InstTemplate->getFriendObjectKind() != Decl::FOK_None);2564 2565  // Link the instantiation back to the pattern *unless* this is a2566  // non-definition friend declaration.2567  if (!InstTemplate->getInstantiatedFromMemberTemplate() &&2568      !(isFriend && !D->getTemplatedDecl()->isThisDeclarationADefinition()))2569    InstTemplate->setInstantiatedFromMemberTemplate(D);2570 2571  // Make declarations visible in the appropriate context.2572  if (!isFriend) {2573    Owner->addDecl(InstTemplate);2574  } else if (InstTemplate->getDeclContext()->isRecord() &&2575             !getPreviousDeclForInstantiation(D)) {2576    SemaRef.CheckFriendAccess(InstTemplate);2577  }2578 2579  return InstTemplate;2580}2581 2582Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {2583  CXXRecordDecl *PrevDecl = nullptr;2584  if (CXXRecordDecl *PatternPrev = getPreviousDeclForInstantiation(D)) {2585    NamedDecl *Prev = SemaRef.FindInstantiatedDecl(D->getLocation(),2586                                                   PatternPrev,2587                                                   TemplateArgs);2588    if (!Prev) return nullptr;2589    PrevDecl = cast<CXXRecordDecl>(Prev);2590  }2591 2592  CXXRecordDecl *Record = nullptr;2593  bool IsInjectedClassName = D->isInjectedClassName();2594  if (D->isLambda())2595    Record = CXXRecordDecl::CreateLambda(2596        SemaRef.Context, Owner, D->getLambdaTypeInfo(), D->getLocation(),2597        D->getLambdaDependencyKind(), D->isGenericLambda(),2598        D->getLambdaCaptureDefault());2599  else2600    Record = CXXRecordDecl::Create(SemaRef.Context, D->getTagKind(), Owner,2601                                   D->getBeginLoc(), D->getLocation(),2602                                   D->getIdentifier(), PrevDecl);2603 2604  Record->setImplicit(D->isImplicit());2605 2606  // Substitute the nested name specifier, if any.2607  if (SubstQualifier(D, Record))2608    return nullptr;2609 2610  SemaRef.InstantiateAttrsForDecl(TemplateArgs, D, Record, LateAttrs,2611                                                              StartingScope);2612 2613  // FIXME: Check against AS_none is an ugly hack to work around the issue that2614  // the tag decls introduced by friend class declarations don't have an access2615  // specifier. Remove once this area of the code gets sorted out.2616  if (D->getAccess() != AS_none)2617    Record->setAccess(D->getAccess());2618  if (!IsInjectedClassName)2619    Record->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);2620 2621  // If the original function was part of a friend declaration,2622  // inherit its namespace state.2623  if (D->getFriendObjectKind())2624    Record->setObjectOfFriendDecl();2625 2626  // Make sure that anonymous structs and unions are recorded.2627  if (D->isAnonymousStructOrUnion())2628    Record->setAnonymousStructOrUnion(true);2629 2630  if (D->isLocalClass())2631    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Record);2632 2633  // Forward the mangling number from the template to the instantiated decl.2634  SemaRef.Context.setManglingNumber(Record,2635                                    SemaRef.Context.getManglingNumber(D));2636 2637  // See if the old tag was defined along with a declarator.2638  // If it did, mark the new tag as being associated with that declarator.2639  if (DeclaratorDecl *DD = SemaRef.Context.getDeclaratorForUnnamedTagDecl(D))2640    SemaRef.Context.addDeclaratorForUnnamedTagDecl(Record, DD);2641 2642  // See if the old tag was defined along with a typedef.2643  // If it did, mark the new tag as being associated with that typedef.2644  if (TypedefNameDecl *TND = SemaRef.Context.getTypedefNameForUnnamedTagDecl(D))2645    SemaRef.Context.addTypedefNameForUnnamedTagDecl(Record, TND);2646 2647  Owner->addDecl(Record);2648 2649  // DR1484 clarifies that the members of a local class are instantiated as part2650  // of the instantiation of their enclosing entity.2651  if (D->isCompleteDefinition() && D->isLocalClass()) {2652    Sema::LocalEagerInstantiationScope LocalInstantiations(SemaRef,2653                                                           /*AtEndOfTU=*/false);2654 2655    SemaRef.InstantiateClass(D->getLocation(), Record, D, TemplateArgs,2656                             TSK_ImplicitInstantiation,2657                             /*Complain=*/true);2658 2659    // For nested local classes, we will instantiate the members when we2660    // reach the end of the outermost (non-nested) local class.2661    if (!D->isCXXClassMember())2662      SemaRef.InstantiateClassMembers(D->getLocation(), Record, TemplateArgs,2663                                      TSK_ImplicitInstantiation);2664 2665    // This class may have local implicit instantiations that need to be2666    // performed within this scope.2667    LocalInstantiations.perform();2668  }2669 2670  SemaRef.DiagnoseUnusedNestedTypedefs(Record);2671 2672  if (IsInjectedClassName)2673    assert(Record->isInjectedClassName() && "Broken injected-class-name");2674 2675  return Record;2676}2677 2678/// Adjust the given function type for an instantiation of the2679/// given declaration, to cope with modifications to the function's type that2680/// aren't reflected in the type-source information.2681///2682/// \param D The declaration we're instantiating.2683/// \param TInfo The already-instantiated type.2684static QualType adjustFunctionTypeForInstantiation(ASTContext &Context,2685                                                   FunctionDecl *D,2686                                                   TypeSourceInfo *TInfo) {2687  const FunctionProtoType *OrigFunc2688    = D->getType()->castAs<FunctionProtoType>();2689  const FunctionProtoType *NewFunc2690    = TInfo->getType()->castAs<FunctionProtoType>();2691  if (OrigFunc->getExtInfo() == NewFunc->getExtInfo())2692    return TInfo->getType();2693 2694  FunctionProtoType::ExtProtoInfo NewEPI = NewFunc->getExtProtoInfo();2695  NewEPI.ExtInfo = OrigFunc->getExtInfo();2696  return Context.getFunctionType(NewFunc->getReturnType(),2697                                 NewFunc->getParamTypes(), NewEPI);2698}2699 2700/// Normal class members are of more specific types and therefore2701/// don't make it here.  This function serves three purposes:2702///   1) instantiating function templates2703///   2) substituting friend and local function declarations2704///   3) substituting deduction guide declarations for nested class templates2705Decl *TemplateDeclInstantiator::VisitFunctionDecl(2706    FunctionDecl *D, TemplateParameterList *TemplateParams,2707    RewriteKind FunctionRewriteKind) {2708  // Check whether there is already a function template specialization for2709  // this declaration.2710  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();2711  bool isFriend;2712  if (FunctionTemplate)2713    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);2714  else2715    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);2716 2717  // Friend function defined withing class template may stop being function2718  // definition during AST merges from different modules, in this case decl2719  // with function body should be used for instantiation.2720  if (ExternalASTSource *Source = SemaRef.Context.getExternalSource()) {2721    if (isFriend && Source->wasThisDeclarationADefinition(D)) {2722      const FunctionDecl *Defn = nullptr;2723      if (D->hasBody(Defn)) {2724        D = const_cast<FunctionDecl *>(Defn);2725        FunctionTemplate = Defn->getDescribedFunctionTemplate();2726      }2727    }2728  }2729 2730  if (FunctionTemplate && !TemplateParams) {2731    ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();2732 2733    void *InsertPos = nullptr;2734    FunctionDecl *SpecFunc2735      = FunctionTemplate->findSpecialization(Innermost, InsertPos);2736 2737    // If we already have a function template specialization, return it.2738    if (SpecFunc)2739      return SpecFunc;2740  }2741 2742  bool MergeWithParentScope = (TemplateParams != nullptr) ||2743    Owner->isFunctionOrMethod() ||2744    !(isa<Decl>(Owner) &&2745      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());2746  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);2747 2748  ExplicitSpecifier InstantiatedExplicitSpecifier;2749  if (auto *DGuide = dyn_cast<CXXDeductionGuideDecl>(D)) {2750    InstantiatedExplicitSpecifier = SemaRef.instantiateExplicitSpecifier(2751        TemplateArgs, DGuide->getExplicitSpecifier());2752    if (InstantiatedExplicitSpecifier.isInvalid())2753      return nullptr;2754  }2755 2756  SmallVector<ParmVarDecl *, 4> Params;2757  TypeSourceInfo *TInfo = SubstFunctionType(D, Params);2758  if (!TInfo)2759    return nullptr;2760  QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);2761 2762  if (TemplateParams && TemplateParams->size()) {2763    auto *LastParam =2764        dyn_cast<TemplateTypeParmDecl>(TemplateParams->asArray().back());2765    if (LastParam && LastParam->isImplicit() &&2766        LastParam->hasTypeConstraint()) {2767      // In abbreviated templates, the type-constraints of invented template2768      // type parameters are instantiated with the function type, invalidating2769      // the TemplateParameterList which relied on the template type parameter2770      // not having a type constraint. Recreate the TemplateParameterList with2771      // the updated parameter list.2772      TemplateParams = TemplateParameterList::Create(2773          SemaRef.Context, TemplateParams->getTemplateLoc(),2774          TemplateParams->getLAngleLoc(), TemplateParams->asArray(),2775          TemplateParams->getRAngleLoc(), TemplateParams->getRequiresClause());2776    }2777  }2778 2779  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();2780  if (QualifierLoc) {2781    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,2782                                                       TemplateArgs);2783    if (!QualifierLoc)2784      return nullptr;2785  }2786 2787  AssociatedConstraint TrailingRequiresClause = D->getTrailingRequiresClause();2788 2789  // If we're instantiating a local function declaration, put the result2790  // in the enclosing namespace; otherwise we need to find the instantiated2791  // context.2792  DeclContext *DC;2793  if (D->isLocalExternDecl()) {2794    DC = Owner;2795    SemaRef.adjustContextForLocalExternDecl(DC);2796  } else if (isFriend && QualifierLoc) {2797    CXXScopeSpec SS;2798    SS.Adopt(QualifierLoc);2799    DC = SemaRef.computeDeclContext(SS);2800    if (!DC) return nullptr;2801  } else {2802    DC = SemaRef.FindInstantiatedContext(D->getLocation(), D->getDeclContext(),2803                                         TemplateArgs);2804  }2805 2806  DeclarationNameInfo NameInfo2807    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);2808 2809  if (FunctionRewriteKind != RewriteKind::None)2810    adjustForRewrite(FunctionRewriteKind, D, T, TInfo, NameInfo);2811 2812  FunctionDecl *Function;2813  if (auto *DGuide = dyn_cast<CXXDeductionGuideDecl>(D)) {2814    Function = CXXDeductionGuideDecl::Create(2815        SemaRef.Context, DC, D->getInnerLocStart(),2816        InstantiatedExplicitSpecifier, NameInfo, T, TInfo,2817        D->getSourceRange().getEnd(), DGuide->getCorrespondingConstructor(),2818        DGuide->getDeductionCandidateKind(), TrailingRequiresClause,2819        DGuide->getSourceDeductionGuide(),2820        DGuide->getSourceDeductionGuideKind());2821    Function->setAccess(D->getAccess());2822  } else {2823    Function = FunctionDecl::Create(2824        SemaRef.Context, DC, D->getInnerLocStart(), NameInfo, T, TInfo,2825        D->getCanonicalDecl()->getStorageClass(), D->UsesFPIntrin(),2826        D->isInlineSpecified(), D->hasWrittenPrototype(), D->getConstexprKind(),2827        TrailingRequiresClause);2828    Function->setFriendConstraintRefersToEnclosingTemplate(2829        D->FriendConstraintRefersToEnclosingTemplate());2830    Function->setRangeEnd(D->getSourceRange().getEnd());2831  }2832 2833  if (D->isInlined())2834    Function->setImplicitlyInline();2835 2836  if (QualifierLoc)2837    Function->setQualifierInfo(QualifierLoc);2838 2839  if (D->isLocalExternDecl())2840    Function->setLocalExternDecl();2841 2842  DeclContext *LexicalDC = Owner;2843  if (!isFriend && D->isOutOfLine() && !D->isLocalExternDecl()) {2844    assert(D->getDeclContext()->isFileContext());2845    LexicalDC = D->getDeclContext();2846  }2847  else if (D->isLocalExternDecl()) {2848    LexicalDC = SemaRef.CurContext;2849  }2850 2851  Function->setIsDestroyingOperatorDelete(D->isDestroyingOperatorDelete());2852  Function->setIsTypeAwareOperatorNewOrDelete(2853      D->isTypeAwareOperatorNewOrDelete());2854  Function->setLexicalDeclContext(LexicalDC);2855 2856  // Attach the parameters2857  for (unsigned P = 0; P < Params.size(); ++P)2858    if (Params[P])2859      Params[P]->setOwningFunction(Function);2860  Function->setParams(Params);2861 2862  if (TrailingRequiresClause)2863    Function->setTrailingRequiresClause(TrailingRequiresClause);2864 2865  if (TemplateParams) {2866    // Our resulting instantiation is actually a function template, since we2867    // are substituting only the outer template parameters. For example, given2868    //2869    //   template<typename T>2870    //   struct X {2871    //     template<typename U> friend void f(T, U);2872    //   };2873    //2874    //   X<int> x;2875    //2876    // We are instantiating the friend function template "f" within X<int>,2877    // which means substituting int for T, but leaving "f" as a friend function2878    // template.2879    // Build the function template itself.2880    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, DC,2881                                                    Function->getLocation(),2882                                                    Function->getDeclName(),2883                                                    TemplateParams, Function);2884    Function->setDescribedFunctionTemplate(FunctionTemplate);2885 2886    FunctionTemplate->setLexicalDeclContext(LexicalDC);2887 2888    if (isFriend && D->isThisDeclarationADefinition()) {2889      FunctionTemplate->setInstantiatedFromMemberTemplate(2890                                           D->getDescribedFunctionTemplate());2891    }2892  } else if (FunctionTemplate &&2893             SemaRef.CodeSynthesisContexts.back().Kind !=2894                 Sema::CodeSynthesisContext::BuildingDeductionGuides) {2895    // Record this function template specialization.2896    ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();2897    Function->setFunctionTemplateSpecialization(FunctionTemplate,2898                            TemplateArgumentList::CreateCopy(SemaRef.Context,2899                                                             Innermost),2900                                                /*InsertPos=*/nullptr);2901  } else if (FunctionRewriteKind == RewriteKind::None) {2902    if (isFriend && D->isThisDeclarationADefinition()) {2903      // Do not connect the friend to the template unless it's actually a2904      // definition. We don't want non-template functions to be marked as being2905      // template instantiations.2906      Function->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);2907    } else if (!isFriend) {2908      // If this is not a function template, and this is not a friend (that is,2909      // this is a locally declared function), save the instantiation2910      // relationship for the purposes of constraint instantiation.2911      Function->setInstantiatedFromDecl(D);2912    }2913  }2914 2915  if (isFriend) {2916    Function->setObjectOfFriendDecl();2917    if (FunctionTemplateDecl *FT = Function->getDescribedFunctionTemplate())2918      FT->setObjectOfFriendDecl();2919  }2920 2921  if (InitFunctionInstantiation(Function, D))2922    Function->setInvalidDecl();2923 2924  bool IsExplicitSpecialization = false;2925 2926  LookupResult Previous(2927      SemaRef, Function->getDeclName(), SourceLocation(),2928      D->isLocalExternDecl() ? Sema::LookupRedeclarationWithLinkage2929                             : Sema::LookupOrdinaryName,2930      D->isLocalExternDecl() ? RedeclarationKind::ForExternalRedeclaration2931                             : SemaRef.forRedeclarationInCurContext());2932 2933  if (DependentFunctionTemplateSpecializationInfo *DFTSI =2934          D->getDependentSpecializationInfo()) {2935    assert(isFriend && "dependent specialization info on "2936                       "non-member non-friend function?");2937 2938    // Instantiate the explicit template arguments.2939    TemplateArgumentListInfo ExplicitArgs;2940    if (const auto *ArgsWritten = DFTSI->TemplateArgumentsAsWritten) {2941      ExplicitArgs.setLAngleLoc(ArgsWritten->getLAngleLoc());2942      ExplicitArgs.setRAngleLoc(ArgsWritten->getRAngleLoc());2943      if (SemaRef.SubstTemplateArguments(ArgsWritten->arguments(), TemplateArgs,2944                                         ExplicitArgs))2945        return nullptr;2946    }2947 2948    // Map the candidates for the primary template to their instantiations.2949    for (FunctionTemplateDecl *FTD : DFTSI->getCandidates()) {2950      if (NamedDecl *ND =2951              SemaRef.FindInstantiatedDecl(D->getLocation(), FTD, TemplateArgs))2952        Previous.addDecl(ND);2953      else2954        return nullptr;2955    }2956 2957    if (SemaRef.CheckFunctionTemplateSpecialization(2958            Function,2959            DFTSI->TemplateArgumentsAsWritten ? &ExplicitArgs : nullptr,2960            Previous))2961      Function->setInvalidDecl();2962 2963    IsExplicitSpecialization = true;2964  } else if (const ASTTemplateArgumentListInfo *ArgsWritten =2965                 D->getTemplateSpecializationArgsAsWritten()) {2966    // The name of this function was written as a template-id.2967    SemaRef.LookupQualifiedName(Previous, DC);2968 2969    // Instantiate the explicit template arguments.2970    TemplateArgumentListInfo ExplicitArgs(ArgsWritten->getLAngleLoc(),2971                                          ArgsWritten->getRAngleLoc());2972    if (SemaRef.SubstTemplateArguments(ArgsWritten->arguments(), TemplateArgs,2973                                       ExplicitArgs))2974      return nullptr;2975 2976    if (SemaRef.CheckFunctionTemplateSpecialization(Function,2977                                                    &ExplicitArgs,2978                                                    Previous))2979      Function->setInvalidDecl();2980 2981    IsExplicitSpecialization = true;2982  } else if (TemplateParams || !FunctionTemplate) {2983    // Look only into the namespace where the friend would be declared to2984    // find a previous declaration. This is the innermost enclosing namespace,2985    // as described in ActOnFriendFunctionDecl.2986    SemaRef.LookupQualifiedName(Previous, DC->getRedeclContext());2987 2988    // In C++, the previous declaration we find might be a tag type2989    // (class or enum). In this case, the new declaration will hide the2990    // tag type. Note that this does not apply if we're declaring a2991    // typedef (C++ [dcl.typedef]p4).2992    if (Previous.isSingleTagDecl())2993      Previous.clear();2994 2995    // Filter out previous declarations that don't match the scope. The only2996    // effect this has is to remove declarations found in inline namespaces2997    // for friend declarations with unqualified names.2998    if (isFriend && !QualifierLoc) {2999      SemaRef.FilterLookupForScope(Previous, DC, /*Scope=*/ nullptr,3000                                   /*ConsiderLinkage=*/ true,3001                                   QualifierLoc.hasQualifier());3002    }3003  }3004 3005  // Per [temp.inst], default arguments in function declarations at local scope3006  // are instantiated along with the enclosing declaration. For example:3007  //3008  //   template<typename T>3009  //   void ft() {3010  //     void f(int = []{ return T::value; }());3011  //   }3012  //   template void ft<int>(); // error: type 'int' cannot be used prior3013  //                                      to '::' because it has no members3014  //3015  // The error is issued during instantiation of ft<int>() because substitution3016  // into the default argument fails; the default argument is instantiated even3017  // though it is never used.3018  if (Function->isLocalExternDecl()) {3019    for (ParmVarDecl *PVD : Function->parameters()) {3020      if (!PVD->hasDefaultArg())3021        continue;3022      if (SemaRef.SubstDefaultArgument(D->getInnerLocStart(), PVD, TemplateArgs)) {3023        // If substitution fails, the default argument is set to a3024        // RecoveryExpr that wraps the uninstantiated default argument so3025        // that downstream diagnostics are omitted.3026        Expr *UninstExpr = PVD->getUninstantiatedDefaultArg();3027        ExprResult ErrorResult = SemaRef.CreateRecoveryExpr(3028            UninstExpr->getBeginLoc(), UninstExpr->getEndLoc(),3029            { UninstExpr }, UninstExpr->getType());3030        if (ErrorResult.isUsable())3031          PVD->setDefaultArg(ErrorResult.get());3032      }3033    }3034  }3035 3036  SemaRef.CheckFunctionDeclaration(/*Scope*/ nullptr, Function, Previous,3037                                   IsExplicitSpecialization,3038                                   Function->isThisDeclarationADefinition());3039 3040  // Check the template parameter list against the previous declaration. The3041  // goal here is to pick up default arguments added since the friend was3042  // declared; we know the template parameter lists match, since otherwise3043  // we would not have picked this template as the previous declaration.3044  if (isFriend && TemplateParams && FunctionTemplate->getPreviousDecl()) {3045    SemaRef.CheckTemplateParameterList(3046        TemplateParams,3047        FunctionTemplate->getPreviousDecl()->getTemplateParameters(),3048        Function->isThisDeclarationADefinition()3049            ? Sema::TPC_FriendFunctionTemplateDefinition3050            : Sema::TPC_FriendFunctionTemplate);3051  }3052 3053  // If we're introducing a friend definition after the first use, trigger3054  // instantiation.3055  // FIXME: If this is a friend function template definition, we should check3056  // to see if any specializations have been used.3057  if (isFriend && D->isThisDeclarationADefinition() && Function->isUsed(false)) {3058    if (MemberSpecializationInfo *MSInfo =3059            Function->getMemberSpecializationInfo()) {3060      if (MSInfo->getPointOfInstantiation().isInvalid()) {3061        SourceLocation Loc = D->getLocation(); // FIXME3062        MSInfo->setPointOfInstantiation(Loc);3063        SemaRef.PendingLocalImplicitInstantiations.emplace_back(Function, Loc);3064      }3065    }3066  }3067 3068  if (D->isExplicitlyDefaulted()) {3069    if (SubstDefaultedFunction(Function, D))3070      return nullptr;3071  }3072  if (D->isDeleted())3073    SemaRef.SetDeclDeleted(Function, D->getLocation(), D->getDeletedMessage());3074 3075  NamedDecl *PrincipalDecl =3076      (TemplateParams ? cast<NamedDecl>(FunctionTemplate) : Function);3077 3078  // If this declaration lives in a different context from its lexical context,3079  // add it to the corresponding lookup table.3080  if (isFriend ||3081      (Function->isLocalExternDecl() && !Function->getPreviousDecl()))3082    DC->makeDeclVisibleInContext(PrincipalDecl);3083 3084  if (Function->isOverloadedOperator() && !DC->isRecord() &&3085      PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))3086    PrincipalDecl->setNonMemberOperator();3087 3088  return Function;3089}3090 3091Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(3092    CXXMethodDecl *D, TemplateParameterList *TemplateParams,3093    RewriteKind FunctionRewriteKind) {3094  FunctionTemplateDecl *FunctionTemplate = D->getDescribedFunctionTemplate();3095  if (FunctionTemplate && !TemplateParams) {3096    // We are creating a function template specialization from a function3097    // template. Check whether there is already a function template3098    // specialization for this particular set of template arguments.3099    ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();3100 3101    void *InsertPos = nullptr;3102    FunctionDecl *SpecFunc3103      = FunctionTemplate->findSpecialization(Innermost, InsertPos);3104 3105    // If we already have a function template specialization, return it.3106    if (SpecFunc)3107      return SpecFunc;3108  }3109 3110  bool isFriend;3111  if (FunctionTemplate)3112    isFriend = (FunctionTemplate->getFriendObjectKind() != Decl::FOK_None);3113  else3114    isFriend = (D->getFriendObjectKind() != Decl::FOK_None);3115 3116  bool MergeWithParentScope = (TemplateParams != nullptr) ||3117    !(isa<Decl>(Owner) &&3118      cast<Decl>(Owner)->isDefinedOutsideFunctionOrMethod());3119  LocalInstantiationScope Scope(SemaRef, MergeWithParentScope);3120 3121  Sema::LambdaScopeForCallOperatorInstantiationRAII LambdaScope(3122      SemaRef, D, TemplateArgs, Scope);3123 3124  // Instantiate enclosing template arguments for friends.3125  SmallVector<TemplateParameterList *, 4> TempParamLists;3126  unsigned NumTempParamLists = 0;3127  if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {3128    TempParamLists.resize(NumTempParamLists);3129    for (unsigned I = 0; I != NumTempParamLists; ++I) {3130      TemplateParameterList *TempParams = D->getTemplateParameterList(I);3131      TemplateParameterList *InstParams = SubstTemplateParams(TempParams);3132      if (!InstParams)3133        return nullptr;3134      TempParamLists[I] = InstParams;3135    }3136  }3137 3138  auto InstantiatedExplicitSpecifier = ExplicitSpecifier::getFromDecl(D);3139  // deduction guides need this3140  const bool CouldInstantiate =3141      InstantiatedExplicitSpecifier.getExpr() == nullptr ||3142      !InstantiatedExplicitSpecifier.getExpr()->isValueDependent();3143 3144  // Delay the instantiation of the explicit-specifier until after the3145  // constraints are checked during template argument deduction.3146  if (CouldInstantiate ||3147      SemaRef.CodeSynthesisContexts.back().Kind !=3148          Sema::CodeSynthesisContext::DeducedTemplateArgumentSubstitution) {3149    InstantiatedExplicitSpecifier = SemaRef.instantiateExplicitSpecifier(3150        TemplateArgs, InstantiatedExplicitSpecifier);3151 3152    if (InstantiatedExplicitSpecifier.isInvalid())3153      return nullptr;3154  } else {3155    InstantiatedExplicitSpecifier.setKind(ExplicitSpecKind::Unresolved);3156  }3157 3158  // Implicit destructors/constructors created for local classes in3159  // DeclareImplicit* (see SemaDeclCXX.cpp) might not have an associated TSI.3160  // Unfortunately there isn't enough context in those functions to3161  // conditionally populate the TSI without breaking non-template related use3162  // cases. Populate TSIs prior to calling SubstFunctionType to make sure we get3163  // a proper transformation.3164  if (isLambdaMethod(D) && !D->getTypeSourceInfo() &&3165      isa<CXXConstructorDecl, CXXDestructorDecl>(D)) {3166    TypeSourceInfo *TSI =3167        SemaRef.Context.getTrivialTypeSourceInfo(D->getType());3168    D->setTypeSourceInfo(TSI);3169  }3170 3171  SmallVector<ParmVarDecl *, 4> Params;3172  TypeSourceInfo *TInfo = SubstFunctionType(D, Params);3173  if (!TInfo)3174    return nullptr;3175  QualType T = adjustFunctionTypeForInstantiation(SemaRef.Context, D, TInfo);3176 3177  if (TemplateParams && TemplateParams->size()) {3178    auto *LastParam =3179        dyn_cast<TemplateTypeParmDecl>(TemplateParams->asArray().back());3180    if (LastParam && LastParam->isImplicit() &&3181        LastParam->hasTypeConstraint()) {3182      // In abbreviated templates, the type-constraints of invented template3183      // type parameters are instantiated with the function type, invalidating3184      // the TemplateParameterList which relied on the template type parameter3185      // not having a type constraint. Recreate the TemplateParameterList with3186      // the updated parameter list.3187      TemplateParams = TemplateParameterList::Create(3188          SemaRef.Context, TemplateParams->getTemplateLoc(),3189          TemplateParams->getLAngleLoc(), TemplateParams->asArray(),3190          TemplateParams->getRAngleLoc(), TemplateParams->getRequiresClause());3191    }3192  }3193 3194  NestedNameSpecifierLoc QualifierLoc = D->getQualifierLoc();3195  if (QualifierLoc) {3196    QualifierLoc = SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc,3197                                                 TemplateArgs);3198    if (!QualifierLoc)3199      return nullptr;3200  }3201 3202  DeclContext *DC = Owner;3203  if (isFriend) {3204    if (QualifierLoc) {3205      CXXScopeSpec SS;3206      SS.Adopt(QualifierLoc);3207      DC = SemaRef.computeDeclContext(SS);3208 3209      if (DC && SemaRef.RequireCompleteDeclContext(SS, DC))3210        return nullptr;3211    } else {3212      DC = SemaRef.FindInstantiatedContext(D->getLocation(),3213                                           D->getDeclContext(),3214                                           TemplateArgs);3215    }3216    if (!DC) return nullptr;3217  }3218 3219  CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);3220  AssociatedConstraint TrailingRequiresClause = D->getTrailingRequiresClause();3221 3222  DeclarationNameInfo NameInfo3223    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);3224 3225  if (FunctionRewriteKind != RewriteKind::None)3226    adjustForRewrite(FunctionRewriteKind, D, T, TInfo, NameInfo);3227 3228  // Build the instantiated method declaration.3229  CXXMethodDecl *Method = nullptr;3230 3231  SourceLocation StartLoc = D->getInnerLocStart();3232  if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {3233    Method = CXXConstructorDecl::Create(3234        SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo,3235        InstantiatedExplicitSpecifier, Constructor->UsesFPIntrin(),3236        Constructor->isInlineSpecified(), false,3237        Constructor->getConstexprKind(), InheritedConstructor(),3238        TrailingRequiresClause);3239    Method->setRangeEnd(Constructor->getEndLoc());3240  } else if (CXXDestructorDecl *Destructor = dyn_cast<CXXDestructorDecl>(D)) {3241    Method = CXXDestructorDecl::Create(3242        SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo,3243        Destructor->UsesFPIntrin(), Destructor->isInlineSpecified(), false,3244        Destructor->getConstexprKind(), TrailingRequiresClause);3245    Method->setIneligibleOrNotSelected(true);3246    Method->setRangeEnd(Destructor->getEndLoc());3247    Method->setDeclName(SemaRef.Context.DeclarationNames.getCXXDestructorName(3248 3249        SemaRef.Context.getCanonicalTagType(Record)));3250  } else if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(D)) {3251    Method = CXXConversionDecl::Create(3252        SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo,3253        Conversion->UsesFPIntrin(), Conversion->isInlineSpecified(),3254        InstantiatedExplicitSpecifier, Conversion->getConstexprKind(),3255        Conversion->getEndLoc(), TrailingRequiresClause);3256  } else {3257    StorageClass SC = D->isStatic() ? SC_Static : SC_None;3258    Method = CXXMethodDecl::Create(3259        SemaRef.Context, Record, StartLoc, NameInfo, T, TInfo, SC,3260        D->UsesFPIntrin(), D->isInlineSpecified(), D->getConstexprKind(),3261        D->getEndLoc(), TrailingRequiresClause);3262  }3263 3264  if (D->isInlined())3265    Method->setImplicitlyInline();3266 3267  if (QualifierLoc)3268    Method->setQualifierInfo(QualifierLoc);3269 3270  if (TemplateParams) {3271    // Our resulting instantiation is actually a function template, since we3272    // are substituting only the outer template parameters. For example, given3273    //3274    //   template<typename T>3275    //   struct X {3276    //     template<typename U> void f(T, U);3277    //   };3278    //3279    //   X<int> x;3280    //3281    // We are instantiating the member template "f" within X<int>, which means3282    // substituting int for T, but leaving "f" as a member function template.3283    // Build the function template itself.3284    FunctionTemplate = FunctionTemplateDecl::Create(SemaRef.Context, Record,3285                                                    Method->getLocation(),3286                                                    Method->getDeclName(),3287                                                    TemplateParams, Method);3288    if (isFriend) {3289      FunctionTemplate->setLexicalDeclContext(Owner);3290      FunctionTemplate->setObjectOfFriendDecl();3291    } else if (D->isOutOfLine())3292      FunctionTemplate->setLexicalDeclContext(D->getLexicalDeclContext());3293    Method->setDescribedFunctionTemplate(FunctionTemplate);3294  } else if (FunctionTemplate) {3295    // Record this function template specialization.3296    ArrayRef<TemplateArgument> Innermost = TemplateArgs.getInnermost();3297    Method->setFunctionTemplateSpecialization(FunctionTemplate,3298                         TemplateArgumentList::CreateCopy(SemaRef.Context,3299                                                          Innermost),3300                                              /*InsertPos=*/nullptr);3301  } else if (!isFriend && FunctionRewriteKind == RewriteKind::None) {3302    // Record that this is an instantiation of a member function.3303    Method->setInstantiationOfMemberFunction(D, TSK_ImplicitInstantiation);3304  }3305 3306  // If we are instantiating a member function defined3307  // out-of-line, the instantiation will have the same lexical3308  // context (which will be a namespace scope) as the template.3309  if (isFriend) {3310    if (NumTempParamLists)3311      Method->setTemplateParameterListsInfo(3312          SemaRef.Context,3313          llvm::ArrayRef(TempParamLists.data(), NumTempParamLists));3314 3315    Method->setLexicalDeclContext(Owner);3316    Method->setObjectOfFriendDecl();3317  } else if (D->isOutOfLine())3318    Method->setLexicalDeclContext(D->getLexicalDeclContext());3319 3320  // Attach the parameters3321  for (unsigned P = 0; P < Params.size(); ++P)3322    Params[P]->setOwningFunction(Method);3323  Method->setParams(Params);3324 3325  if (InitMethodInstantiation(Method, D))3326    Method->setInvalidDecl();3327 3328  LookupResult Previous(SemaRef, NameInfo, Sema::LookupOrdinaryName,3329                        RedeclarationKind::ForExternalRedeclaration);3330 3331  bool IsExplicitSpecialization = false;3332 3333  // If the name of this function was written as a template-id, instantiate3334  // the explicit template arguments.3335  if (DependentFunctionTemplateSpecializationInfo *DFTSI =3336          D->getDependentSpecializationInfo()) {3337    // Instantiate the explicit template arguments.3338    TemplateArgumentListInfo ExplicitArgs;3339    if (const auto *ArgsWritten = DFTSI->TemplateArgumentsAsWritten) {3340      ExplicitArgs.setLAngleLoc(ArgsWritten->getLAngleLoc());3341      ExplicitArgs.setRAngleLoc(ArgsWritten->getRAngleLoc());3342      if (SemaRef.SubstTemplateArguments(ArgsWritten->arguments(), TemplateArgs,3343                                         ExplicitArgs))3344        return nullptr;3345    }3346 3347    // Map the candidates for the primary template to their instantiations.3348    for (FunctionTemplateDecl *FTD : DFTSI->getCandidates()) {3349      if (NamedDecl *ND =3350              SemaRef.FindInstantiatedDecl(D->getLocation(), FTD, TemplateArgs))3351        Previous.addDecl(ND);3352      else3353        return nullptr;3354    }3355 3356    if (SemaRef.CheckFunctionTemplateSpecialization(3357            Method, DFTSI->TemplateArgumentsAsWritten ? &ExplicitArgs : nullptr,3358            Previous))3359      Method->setInvalidDecl();3360 3361    IsExplicitSpecialization = true;3362  } else if (const ASTTemplateArgumentListInfo *ArgsWritten =3363                 D->getTemplateSpecializationArgsAsWritten()) {3364    SemaRef.LookupQualifiedName(Previous, DC);3365 3366    TemplateArgumentListInfo ExplicitArgs(ArgsWritten->getLAngleLoc(),3367                                          ArgsWritten->getRAngleLoc());3368 3369    if (SemaRef.SubstTemplateArguments(ArgsWritten->arguments(), TemplateArgs,3370                                       ExplicitArgs))3371      return nullptr;3372 3373    if (SemaRef.CheckFunctionTemplateSpecialization(Method,3374                                                    &ExplicitArgs,3375                                                    Previous))3376      Method->setInvalidDecl();3377 3378    IsExplicitSpecialization = true;3379  } else if (!FunctionTemplate || TemplateParams || isFriend) {3380    SemaRef.LookupQualifiedName(Previous, Record);3381 3382    // In C++, the previous declaration we find might be a tag type3383    // (class or enum). In this case, the new declaration will hide the3384    // tag type. Note that this does not apply if we're declaring a3385    // typedef (C++ [dcl.typedef]p4).3386    if (Previous.isSingleTagDecl())3387      Previous.clear();3388  }3389 3390  // Per [temp.inst], default arguments in member functions of local classes3391  // are instantiated along with the member function declaration. For example:3392  //3393  //   template<typename T>3394  //   void ft() {3395  //     struct lc {3396  //       int operator()(int p = []{ return T::value; }());3397  //     };3398  //   }3399  //   template void ft<int>(); // error: type 'int' cannot be used prior3400  //                                      to '::'because it has no members3401  //3402  // The error is issued during instantiation of ft<int>()::lc::operator()3403  // because substitution into the default argument fails; the default argument3404  // is instantiated even though it is never used.3405  if (D->isInLocalScopeForInstantiation()) {3406    for (unsigned P = 0; P < Params.size(); ++P) {3407      if (!Params[P]->hasDefaultArg())3408        continue;3409      if (SemaRef.SubstDefaultArgument(StartLoc, Params[P], TemplateArgs)) {3410        // If substitution fails, the default argument is set to a3411        // RecoveryExpr that wraps the uninstantiated default argument so3412        // that downstream diagnostics are omitted.3413        Expr *UninstExpr = Params[P]->getUninstantiatedDefaultArg();3414        ExprResult ErrorResult = SemaRef.CreateRecoveryExpr(3415            UninstExpr->getBeginLoc(), UninstExpr->getEndLoc(),3416            { UninstExpr }, UninstExpr->getType());3417        if (ErrorResult.isUsable())3418          Params[P]->setDefaultArg(ErrorResult.get());3419      }3420    }3421  }3422 3423  SemaRef.CheckFunctionDeclaration(nullptr, Method, Previous,3424                                   IsExplicitSpecialization,3425                                   Method->isThisDeclarationADefinition());3426 3427  if (D->isPureVirtual())3428    SemaRef.CheckPureMethod(Method, SourceRange());3429 3430  // Propagate access.  For a non-friend declaration, the access is3431  // whatever we're propagating from.  For a friend, it should be the3432  // previous declaration we just found.3433  if (isFriend && Method->getPreviousDecl())3434    Method->setAccess(Method->getPreviousDecl()->getAccess());3435  else3436    Method->setAccess(D->getAccess());3437  if (FunctionTemplate)3438    FunctionTemplate->setAccess(Method->getAccess());3439 3440  SemaRef.CheckOverrideControl(Method);3441 3442  // If a function is defined as defaulted or deleted, mark it as such now.3443  if (D->isExplicitlyDefaulted()) {3444    if (SubstDefaultedFunction(Method, D))3445      return nullptr;3446  }3447  if (D->isDeletedAsWritten())3448    SemaRef.SetDeclDeleted(Method, Method->getLocation(),3449                           D->getDeletedMessage());3450 3451  // If this is an explicit specialization, mark the implicitly-instantiated3452  // template specialization as being an explicit specialization too.3453  // FIXME: Is this necessary?3454  if (IsExplicitSpecialization && !isFriend)3455    SemaRef.CompleteMemberSpecialization(Method, Previous);3456 3457  // If the method is a special member function, we need to mark it as3458  // ineligible so that Owner->addDecl() won't mark the class as non trivial.3459  // At the end of the class instantiation, we calculate eligibility again and3460  // then we adjust trivility if needed.3461  // We need this check to happen only after the method parameters are set,3462  // because being e.g. a copy constructor depends on the instantiated3463  // arguments.3464  if (auto *Constructor = dyn_cast<CXXConstructorDecl>(Method)) {3465    if (Constructor->isDefaultConstructor() ||3466        Constructor->isCopyOrMoveConstructor())3467      Method->setIneligibleOrNotSelected(true);3468  } else if (Method->isCopyAssignmentOperator() ||3469             Method->isMoveAssignmentOperator()) {3470    Method->setIneligibleOrNotSelected(true);3471  }3472 3473  // If there's a function template, let our caller handle it.3474  if (FunctionTemplate) {3475    // do nothing3476 3477  // Don't hide a (potentially) valid declaration with an invalid one.3478  } else if (Method->isInvalidDecl() && !Previous.empty()) {3479    // do nothing3480 3481  // Otherwise, check access to friends and make them visible.3482  } else if (isFriend) {3483    // We only need to re-check access for methods which we didn't3484    // manage to match during parsing.3485    if (!D->getPreviousDecl())3486      SemaRef.CheckFriendAccess(Method);3487 3488    Record->makeDeclVisibleInContext(Method);3489 3490  // Otherwise, add the declaration.  We don't need to do this for3491  // class-scope specializations because we'll have matched them with3492  // the appropriate template.3493  } else {3494    Owner->addDecl(Method);3495  }3496 3497  // PR17480: Honor the used attribute to instantiate member function3498  // definitions3499  if (Method->hasAttr<UsedAttr>()) {3500    if (const auto *A = dyn_cast<CXXRecordDecl>(Owner)) {3501      SourceLocation Loc;3502      if (const MemberSpecializationInfo *MSInfo =3503              A->getMemberSpecializationInfo())3504        Loc = MSInfo->getPointOfInstantiation();3505      else if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(A))3506        Loc = Spec->getPointOfInstantiation();3507      SemaRef.MarkFunctionReferenced(Loc, Method);3508    }3509  }3510 3511  return Method;3512}3513 3514Decl *TemplateDeclInstantiator::VisitCXXConstructorDecl(CXXConstructorDecl *D) {3515  return VisitCXXMethodDecl(D);3516}3517 3518Decl *TemplateDeclInstantiator::VisitCXXDestructorDecl(CXXDestructorDecl *D) {3519  return VisitCXXMethodDecl(D);3520}3521 3522Decl *TemplateDeclInstantiator::VisitCXXConversionDecl(CXXConversionDecl *D) {3523  return VisitCXXMethodDecl(D);3524}3525 3526Decl *TemplateDeclInstantiator::VisitParmVarDecl(ParmVarDecl *D) {3527  return SemaRef.SubstParmVarDecl(D, TemplateArgs, /*indexAdjustment*/ 0,3528                                  std::nullopt,3529                                  /*ExpectParameterPack=*/false);3530}3531 3532Decl *TemplateDeclInstantiator::VisitTemplateTypeParmDecl(3533                                                    TemplateTypeParmDecl *D) {3534  assert(D->getTypeForDecl()->isTemplateTypeParmType());3535 3536  UnsignedOrNone NumExpanded = std::nullopt;3537 3538  if (const TypeConstraint *TC = D->getTypeConstraint()) {3539    if (D->isPackExpansion() && !D->getNumExpansionParameters()) {3540      assert(TC->getTemplateArgsAsWritten() &&3541             "type parameter can only be an expansion when explicit arguments "3542             "are specified");3543      // The template type parameter pack's type is a pack expansion of types.3544      // Determine whether we need to expand this parameter pack into separate3545      // types.3546      SmallVector<UnexpandedParameterPack, 2> Unexpanded;3547      for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())3548        SemaRef.collectUnexpandedParameterPacks(ArgLoc, Unexpanded);3549 3550      // Determine whether the set of unexpanded parameter packs can and should3551      // be expanded.3552      bool Expand = true;3553      bool RetainExpansion = false;3554      if (SemaRef.CheckParameterPacksForExpansion(3555              cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())3556                  ->getEllipsisLoc(),3557              SourceRange(TC->getConceptNameLoc(),3558                          TC->hasExplicitTemplateArgs()3559                              ? TC->getTemplateArgsAsWritten()->getRAngleLoc()3560                              : TC->getConceptNameInfo().getEndLoc()),3561              Unexpanded, TemplateArgs, /*FailOnPackProducingTemplates=*/true,3562              Expand, RetainExpansion, NumExpanded))3563        return nullptr;3564    }3565  }3566 3567  TemplateTypeParmDecl *Inst = TemplateTypeParmDecl::Create(3568      SemaRef.Context, Owner, D->getBeginLoc(), D->getLocation(),3569      D->getDepth() - TemplateArgs.getNumSubstitutedLevels(), D->getIndex(),3570      D->getIdentifier(), D->wasDeclaredWithTypename(), D->isParameterPack(),3571      D->hasTypeConstraint(), NumExpanded);3572 3573  Inst->setAccess(AS_public);3574  Inst->setImplicit(D->isImplicit());3575  if (auto *TC = D->getTypeConstraint()) {3576    if (!D->isImplicit()) {3577      // Invented template parameter type constraints will be instantiated3578      // with the corresponding auto-typed parameter as it might reference3579      // other parameters.3580      if (SemaRef.SubstTypeConstraint(Inst, TC, TemplateArgs,3581                                      EvaluateConstraints))3582        return nullptr;3583    }3584  }3585  if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {3586    TemplateArgumentLoc Output;3587    if (!SemaRef.SubstTemplateArgument(D->getDefaultArgument(), TemplateArgs,3588                                       Output))3589      Inst->setDefaultArgument(SemaRef.getASTContext(), Output);3590  }3591 3592  // Introduce this template parameter's instantiation into the instantiation3593  // scope.3594  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Inst);3595 3596  return Inst;3597}3598 3599Decl *TemplateDeclInstantiator::VisitNonTypeTemplateParmDecl(3600                                                 NonTypeTemplateParmDecl *D) {3601  // Substitute into the type of the non-type template parameter.3602  TypeLoc TL = D->getTypeSourceInfo()->getTypeLoc();3603  SmallVector<TypeSourceInfo *, 4> ExpandedParameterPackTypesAsWritten;3604  SmallVector<QualType, 4> ExpandedParameterPackTypes;3605  bool IsExpandedParameterPack = false;3606  TypeSourceInfo *TSI;3607  QualType T;3608  bool Invalid = false;3609 3610  if (D->isExpandedParameterPack()) {3611    // The non-type template parameter pack is an already-expanded pack3612    // expansion of types. Substitute into each of the expanded types.3613    ExpandedParameterPackTypes.reserve(D->getNumExpansionTypes());3614    ExpandedParameterPackTypesAsWritten.reserve(D->getNumExpansionTypes());3615    for (unsigned I = 0, N = D->getNumExpansionTypes(); I != N; ++I) {3616      TypeSourceInfo *NewTSI =3617          SemaRef.SubstType(D->getExpansionTypeSourceInfo(I), TemplateArgs,3618                            D->getLocation(), D->getDeclName());3619      if (!NewTSI)3620        return nullptr;3621 3622      QualType NewT =3623          SemaRef.CheckNonTypeTemplateParameterType(NewTSI, D->getLocation());3624      if (NewT.isNull())3625        return nullptr;3626 3627      ExpandedParameterPackTypesAsWritten.push_back(NewTSI);3628      ExpandedParameterPackTypes.push_back(NewT);3629    }3630 3631    IsExpandedParameterPack = true;3632    TSI = D->getTypeSourceInfo();3633    T = TSI->getType();3634  } else if (D->isPackExpansion()) {3635    // The non-type template parameter pack's type is a pack expansion of types.3636    // Determine whether we need to expand this parameter pack into separate3637    // types.3638    PackExpansionTypeLoc Expansion = TL.castAs<PackExpansionTypeLoc>();3639    TypeLoc Pattern = Expansion.getPatternLoc();3640    SmallVector<UnexpandedParameterPack, 2> Unexpanded;3641    SemaRef.collectUnexpandedParameterPacks(Pattern, Unexpanded);3642 3643    // Determine whether the set of unexpanded parameter packs can and should3644    // be expanded.3645    bool Expand = true;3646    bool RetainExpansion = false;3647    UnsignedOrNone OrigNumExpansions =3648        Expansion.getTypePtr()->getNumExpansions();3649    UnsignedOrNone NumExpansions = OrigNumExpansions;3650    if (SemaRef.CheckParameterPacksForExpansion(3651            Expansion.getEllipsisLoc(), Pattern.getSourceRange(), Unexpanded,3652            TemplateArgs, /*FailOnPackProducingTemplates=*/true, Expand,3653            RetainExpansion, NumExpansions))3654      return nullptr;3655 3656    if (Expand) {3657      for (unsigned I = 0; I != *NumExpansions; ++I) {3658        Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, I);3659        TypeSourceInfo *NewTSI = SemaRef.SubstType(3660            Pattern, TemplateArgs, D->getLocation(), D->getDeclName());3661        if (!NewTSI)3662          return nullptr;3663 3664        QualType NewT =3665            SemaRef.CheckNonTypeTemplateParameterType(NewTSI, D->getLocation());3666        if (NewT.isNull())3667          return nullptr;3668 3669        ExpandedParameterPackTypesAsWritten.push_back(NewTSI);3670        ExpandedParameterPackTypes.push_back(NewT);3671      }3672 3673      // Note that we have an expanded parameter pack. The "type" of this3674      // expanded parameter pack is the original expansion type, but callers3675      // will end up using the expanded parameter pack types for type-checking.3676      IsExpandedParameterPack = true;3677      TSI = D->getTypeSourceInfo();3678      T = TSI->getType();3679    } else {3680      // We cannot fully expand the pack expansion now, so substitute into the3681      // pattern and create a new pack expansion type.3682      Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, std::nullopt);3683      TypeSourceInfo *NewPattern = SemaRef.SubstType(Pattern, TemplateArgs,3684                                                     D->getLocation(),3685                                                     D->getDeclName());3686      if (!NewPattern)3687        return nullptr;3688 3689      SemaRef.CheckNonTypeTemplateParameterType(NewPattern, D->getLocation());3690      TSI = SemaRef.CheckPackExpansion(NewPattern, Expansion.getEllipsisLoc(),3691                                       NumExpansions);3692      if (!TSI)3693        return nullptr;3694 3695      T = TSI->getType();3696    }3697  } else {3698    // Simple case: substitution into a parameter that is not a parameter pack.3699    TSI = SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,3700                            D->getLocation(), D->getDeclName());3701    if (!TSI)3702      return nullptr;3703 3704    // Check that this type is acceptable for a non-type template parameter.3705    T = SemaRef.CheckNonTypeTemplateParameterType(TSI, D->getLocation());3706    if (T.isNull()) {3707      T = SemaRef.Context.IntTy;3708      Invalid = true;3709    }3710  }3711 3712  NonTypeTemplateParmDecl *Param;3713  if (IsExpandedParameterPack)3714    Param = NonTypeTemplateParmDecl::Create(3715        SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),3716        D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),3717        D->getPosition(), D->getIdentifier(), T, TSI,3718        ExpandedParameterPackTypes, ExpandedParameterPackTypesAsWritten);3719  else3720    Param = NonTypeTemplateParmDecl::Create(3721        SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),3722        D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),3723        D->getPosition(), D->getIdentifier(), T, D->isParameterPack(), TSI);3724 3725  if (AutoTypeLoc AutoLoc = TSI->getTypeLoc().getContainedAutoTypeLoc())3726    if (AutoLoc.isConstrained()) {3727      SourceLocation EllipsisLoc;3728      if (IsExpandedParameterPack)3729        EllipsisLoc =3730            TSI->getTypeLoc().getAs<PackExpansionTypeLoc>().getEllipsisLoc();3731      else if (auto *Constraint = dyn_cast_if_present<CXXFoldExpr>(3732                   D->getPlaceholderTypeConstraint()))3733        EllipsisLoc = Constraint->getEllipsisLoc();3734      // Note: We attach the uninstantiated constriant here, so that it can be3735      // instantiated relative to the top level, like all our other3736      // constraints.3737      if (SemaRef.AttachTypeConstraint(AutoLoc, /*NewConstrainedParm=*/Param,3738                                       /*OrigConstrainedParm=*/D, EllipsisLoc))3739        Invalid = true;3740    }3741 3742  Param->setAccess(AS_public);3743  Param->setImplicit(D->isImplicit());3744  if (Invalid)3745    Param->setInvalidDecl();3746 3747  if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {3748    EnterExpressionEvaluationContext ConstantEvaluated(3749        SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);3750    TemplateArgumentLoc Result;3751    if (!SemaRef.SubstTemplateArgument(D->getDefaultArgument(), TemplateArgs,3752                                       Result))3753      Param->setDefaultArgument(SemaRef.Context, Result);3754  }3755 3756  // Introduce this template parameter's instantiation into the instantiation3757  // scope.3758  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);3759  return Param;3760}3761 3762static void collectUnexpandedParameterPacks(3763    Sema &S,3764    TemplateParameterList *Params,3765    SmallVectorImpl<UnexpandedParameterPack> &Unexpanded) {3766  for (const auto &P : *Params) {3767    if (P->isTemplateParameterPack())3768      continue;3769    if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P))3770      S.collectUnexpandedParameterPacks(NTTP->getTypeSourceInfo()->getTypeLoc(),3771                                        Unexpanded);3772    if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(P))3773      collectUnexpandedParameterPacks(S, TTP->getTemplateParameters(),3774                                      Unexpanded);3775  }3776}3777 3778Decl *3779TemplateDeclInstantiator::VisitTemplateTemplateParmDecl(3780                                                  TemplateTemplateParmDecl *D) {3781  // Instantiate the template parameter list of the template template parameter.3782  TemplateParameterList *TempParams = D->getTemplateParameters();3783  TemplateParameterList *InstParams;3784  SmallVector<TemplateParameterList*, 8> ExpandedParams;3785 3786  bool IsExpandedParameterPack = false;3787 3788  if (D->isExpandedParameterPack()) {3789    // The template template parameter pack is an already-expanded pack3790    // expansion of template parameters. Substitute into each of the expanded3791    // parameters.3792    ExpandedParams.reserve(D->getNumExpansionTemplateParameters());3793    for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();3794         I != N; ++I) {3795      LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);3796      TemplateParameterList *Expansion =3797        SubstTemplateParams(D->getExpansionTemplateParameters(I));3798      if (!Expansion)3799        return nullptr;3800      ExpandedParams.push_back(Expansion);3801    }3802 3803    IsExpandedParameterPack = true;3804    InstParams = TempParams;3805  } else if (D->isPackExpansion()) {3806    // The template template parameter pack expands to a pack of template3807    // template parameters. Determine whether we need to expand this parameter3808    // pack into separate parameters.3809    SmallVector<UnexpandedParameterPack, 2> Unexpanded;3810    collectUnexpandedParameterPacks(SemaRef, D->getTemplateParameters(),3811                                    Unexpanded);3812 3813    // Determine whether the set of unexpanded parameter packs can and should3814    // be expanded.3815    bool Expand = true;3816    bool RetainExpansion = false;3817    UnsignedOrNone NumExpansions = std::nullopt;3818    if (SemaRef.CheckParameterPacksForExpansion(3819            D->getLocation(), TempParams->getSourceRange(), Unexpanded,3820            TemplateArgs, /*FailOnPackProducingTemplates=*/true, Expand,3821            RetainExpansion, NumExpansions))3822      return nullptr;3823 3824    if (Expand) {3825      for (unsigned I = 0; I != *NumExpansions; ++I) {3826        Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, I);3827        LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);3828        TemplateParameterList *Expansion = SubstTemplateParams(TempParams);3829        if (!Expansion)3830          return nullptr;3831        ExpandedParams.push_back(Expansion);3832      }3833 3834      // Note that we have an expanded parameter pack. The "type" of this3835      // expanded parameter pack is the original expansion type, but callers3836      // will end up using the expanded parameter pack types for type-checking.3837      IsExpandedParameterPack = true;3838    }3839 3840    Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, std::nullopt);3841 3842    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);3843    InstParams = SubstTemplateParams(TempParams);3844    if (!InstParams)3845      return nullptr;3846  } else {3847    // Perform the actual substitution of template parameters within a new,3848    // local instantiation scope.3849    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);3850    InstParams = SubstTemplateParams(TempParams);3851    if (!InstParams)3852      return nullptr;3853  }3854 3855  // Build the template template parameter.3856  TemplateTemplateParmDecl *Param;3857  if (IsExpandedParameterPack)3858    Param = TemplateTemplateParmDecl::Create(3859        SemaRef.Context, Owner, D->getLocation(),3860        D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),3861        D->getPosition(), D->getIdentifier(), D->templateParameterKind(),3862        D->wasDeclaredWithTypename(), InstParams, ExpandedParams);3863  else3864    Param = TemplateTemplateParmDecl::Create(3865        SemaRef.Context, Owner, D->getLocation(),3866        D->getDepth() - TemplateArgs.getNumSubstitutedLevels(),3867        D->getPosition(), D->isParameterPack(), D->getIdentifier(),3868        D->templateParameterKind(), D->wasDeclaredWithTypename(), InstParams);3869  if (D->hasDefaultArgument() && !D->defaultArgumentWasInherited()) {3870    const TemplateArgumentLoc &A = D->getDefaultArgument();3871    NestedNameSpecifierLoc QualifierLoc = A.getTemplateQualifierLoc();3872    // FIXME: Pass in the template keyword location.3873    TemplateName TName = SemaRef.SubstTemplateName(3874        A.getTemplateKWLoc(), QualifierLoc, A.getArgument().getAsTemplate(),3875        A.getTemplateNameLoc(), TemplateArgs);3876    if (!TName.isNull())3877      Param->setDefaultArgument(3878          SemaRef.Context,3879          TemplateArgumentLoc(SemaRef.Context, TemplateArgument(TName),3880                              A.getTemplateKWLoc(), QualifierLoc,3881                              A.getTemplateNameLoc()));3882  }3883  Param->setAccess(AS_public);3884  Param->setImplicit(D->isImplicit());3885 3886  // Introduce this template parameter's instantiation into the instantiation3887  // scope.3888  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, Param);3889 3890  return Param;3891}3892 3893Decl *TemplateDeclInstantiator::VisitUsingDirectiveDecl(UsingDirectiveDecl *D) {3894  // Using directives are never dependent (and never contain any types or3895  // expressions), so they require no explicit instantiation work.3896 3897  UsingDirectiveDecl *Inst3898    = UsingDirectiveDecl::Create(SemaRef.Context, Owner, D->getLocation(),3899                                 D->getNamespaceKeyLocation(),3900                                 D->getQualifierLoc(),3901                                 D->getIdentLocation(),3902                                 D->getNominatedNamespace(),3903                                 D->getCommonAncestor());3904 3905  // Add the using directive to its declaration context3906  // only if this is not a function or method.3907  if (!Owner->isFunctionOrMethod())3908    Owner->addDecl(Inst);3909 3910  return Inst;3911}3912 3913Decl *TemplateDeclInstantiator::VisitBaseUsingDecls(BaseUsingDecl *D,3914                                                    BaseUsingDecl *Inst,3915                                                    LookupResult *Lookup) {3916 3917  bool isFunctionScope = Owner->isFunctionOrMethod();3918 3919  for (auto *Shadow : D->shadows()) {3920    // FIXME: UsingShadowDecl doesn't preserve its immediate target, so3921    // reconstruct it in the case where it matters. Hm, can we extract it from3922    // the DeclSpec when parsing and save it in the UsingDecl itself?3923    NamedDecl *OldTarget = Shadow->getTargetDecl();3924    if (auto *CUSD = dyn_cast<ConstructorUsingShadowDecl>(Shadow))3925      if (auto *BaseShadow = CUSD->getNominatedBaseClassShadowDecl())3926        OldTarget = BaseShadow;3927 3928    NamedDecl *InstTarget = nullptr;3929    if (auto *EmptyD =3930            dyn_cast<UnresolvedUsingIfExistsDecl>(Shadow->getTargetDecl())) {3931      InstTarget = UnresolvedUsingIfExistsDecl::Create(3932          SemaRef.Context, Owner, EmptyD->getLocation(), EmptyD->getDeclName());3933    } else {3934      InstTarget = cast_or_null<NamedDecl>(SemaRef.FindInstantiatedDecl(3935          Shadow->getLocation(), OldTarget, TemplateArgs));3936    }3937    if (!InstTarget)3938      return nullptr;3939 3940    UsingShadowDecl *PrevDecl = nullptr;3941    if (Lookup &&3942        SemaRef.CheckUsingShadowDecl(Inst, InstTarget, *Lookup, PrevDecl))3943      continue;3944 3945    if (UsingShadowDecl *OldPrev = getPreviousDeclForInstantiation(Shadow))3946      PrevDecl = cast_or_null<UsingShadowDecl>(SemaRef.FindInstantiatedDecl(3947          Shadow->getLocation(), OldPrev, TemplateArgs));3948 3949    UsingShadowDecl *InstShadow = SemaRef.BuildUsingShadowDecl(3950        /*Scope*/ nullptr, Inst, InstTarget, PrevDecl);3951    SemaRef.Context.setInstantiatedFromUsingShadowDecl(InstShadow, Shadow);3952 3953    if (isFunctionScope)3954      SemaRef.CurrentInstantiationScope->InstantiatedLocal(Shadow, InstShadow);3955  }3956 3957  return Inst;3958}3959 3960Decl *TemplateDeclInstantiator::VisitUsingDecl(UsingDecl *D) {3961 3962  // The nested name specifier may be dependent, for example3963  //     template <typename T> struct t {3964  //       struct s1 { T f1(); };3965  //       struct s2 : s1 { using s1::f1; };3966  //     };3967  //     template struct t<int>;3968  // Here, in using s1::f1, s1 refers to t<T>::s1;3969  // we need to substitute for t<int>::s1.3970  NestedNameSpecifierLoc QualifierLoc3971    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),3972                                          TemplateArgs);3973  if (!QualifierLoc)3974    return nullptr;3975 3976  // For an inheriting constructor declaration, the name of the using3977  // declaration is the name of a constructor in this class, not in the3978  // base class.3979  DeclarationNameInfo NameInfo = D->getNameInfo();3980  if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName)3981    if (auto *RD = dyn_cast<CXXRecordDecl>(SemaRef.CurContext))3982      NameInfo.setName(SemaRef.Context.DeclarationNames.getCXXConstructorName(3983          SemaRef.Context.getCanonicalTagType(RD)));3984 3985  // We only need to do redeclaration lookups if we're in a class scope (in3986  // fact, it's not really even possible in non-class scopes).3987  bool CheckRedeclaration = Owner->isRecord();3988  LookupResult Prev(SemaRef, NameInfo, Sema::LookupUsingDeclName,3989                    RedeclarationKind::ForVisibleRedeclaration);3990 3991  UsingDecl *NewUD = UsingDecl::Create(SemaRef.Context, Owner,3992                                       D->getUsingLoc(),3993                                       QualifierLoc,3994                                       NameInfo,3995                                       D->hasTypename());3996 3997  CXXScopeSpec SS;3998  SS.Adopt(QualifierLoc);3999  if (CheckRedeclaration) {4000    Prev.setHideTags(false);4001    SemaRef.LookupQualifiedName(Prev, Owner);4002 4003    // Check for invalid redeclarations.4004    if (SemaRef.CheckUsingDeclRedeclaration(D->getUsingLoc(),4005                                            D->hasTypename(), SS,4006                                            D->getLocation(), Prev))4007      NewUD->setInvalidDecl();4008  }4009 4010  if (!NewUD->isInvalidDecl() &&4011      SemaRef.CheckUsingDeclQualifier(D->getUsingLoc(), D->hasTypename(), SS,4012                                      NameInfo, D->getLocation(), nullptr, D))4013    NewUD->setInvalidDecl();4014 4015  SemaRef.Context.setInstantiatedFromUsingDecl(NewUD, D);4016  NewUD->setAccess(D->getAccess());4017  Owner->addDecl(NewUD);4018 4019  // Don't process the shadow decls for an invalid decl.4020  if (NewUD->isInvalidDecl())4021    return NewUD;4022 4023  // If the using scope was dependent, or we had dependent bases, we need to4024  // recheck the inheritance4025  if (NameInfo.getName().getNameKind() == DeclarationName::CXXConstructorName)4026    SemaRef.CheckInheritingConstructorUsingDecl(NewUD);4027 4028  return VisitBaseUsingDecls(D, NewUD, CheckRedeclaration ? &Prev : nullptr);4029}4030 4031Decl *TemplateDeclInstantiator::VisitUsingEnumDecl(UsingEnumDecl *D) {4032  // Cannot be a dependent type, but still could be an instantiation4033  EnumDecl *EnumD = cast_or_null<EnumDecl>(SemaRef.FindInstantiatedDecl(4034      D->getLocation(), D->getEnumDecl(), TemplateArgs));4035 4036  if (SemaRef.RequireCompleteEnumDecl(EnumD, EnumD->getLocation()))4037    return nullptr;4038 4039  TypeSourceInfo *TSI = SemaRef.SubstType(D->getEnumType(), TemplateArgs,4040                                          D->getLocation(), D->getDeclName());4041 4042  if (!TSI)4043    return nullptr;4044 4045  UsingEnumDecl *NewUD =4046      UsingEnumDecl::Create(SemaRef.Context, Owner, D->getUsingLoc(),4047                            D->getEnumLoc(), D->getLocation(), TSI);4048 4049  SemaRef.Context.setInstantiatedFromUsingEnumDecl(NewUD, D);4050  NewUD->setAccess(D->getAccess());4051  Owner->addDecl(NewUD);4052 4053  // Don't process the shadow decls for an invalid decl.4054  if (NewUD->isInvalidDecl())4055    return NewUD;4056 4057  // We don't have to recheck for duplication of the UsingEnumDecl itself, as it4058  // cannot be dependent, and will therefore have been checked during template4059  // definition.4060 4061  return VisitBaseUsingDecls(D, NewUD, nullptr);4062}4063 4064Decl *TemplateDeclInstantiator::VisitUsingShadowDecl(UsingShadowDecl *D) {4065  // Ignore these;  we handle them in bulk when processing the UsingDecl.4066  return nullptr;4067}4068 4069Decl *TemplateDeclInstantiator::VisitConstructorUsingShadowDecl(4070    ConstructorUsingShadowDecl *D) {4071  // Ignore these;  we handle them in bulk when processing the UsingDecl.4072  return nullptr;4073}4074 4075template <typename T>4076Decl *TemplateDeclInstantiator::instantiateUnresolvedUsingDecl(4077    T *D, bool InstantiatingPackElement) {4078  // If this is a pack expansion, expand it now.4079  if (D->isPackExpansion() && !InstantiatingPackElement) {4080    SmallVector<UnexpandedParameterPack, 2> Unexpanded;4081    SemaRef.collectUnexpandedParameterPacks(D->getQualifierLoc(), Unexpanded);4082    SemaRef.collectUnexpandedParameterPacks(D->getNameInfo(), Unexpanded);4083 4084    // Determine whether the set of unexpanded parameter packs can and should4085    // be expanded.4086    bool Expand = true;4087    bool RetainExpansion = false;4088    UnsignedOrNone NumExpansions = std::nullopt;4089    if (SemaRef.CheckParameterPacksForExpansion(4090            D->getEllipsisLoc(), D->getSourceRange(), Unexpanded, TemplateArgs,4091            /*FailOnPackProducingTemplates=*/true, Expand, RetainExpansion,4092            NumExpansions))4093      return nullptr;4094 4095    // This declaration cannot appear within a function template signature,4096    // so we can't have a partial argument list for a parameter pack.4097    assert(!RetainExpansion &&4098           "should never need to retain an expansion for UsingPackDecl");4099 4100    if (!Expand) {4101      // We cannot fully expand the pack expansion now, so substitute into the4102      // pattern and create a new pack expansion.4103      Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, std::nullopt);4104      return instantiateUnresolvedUsingDecl(D, true);4105    }4106 4107    // Within a function, we don't have any normal way to check for conflicts4108    // between shadow declarations from different using declarations in the4109    // same pack expansion, but this is always ill-formed because all expansions4110    // must produce (conflicting) enumerators.4111    //4112    // Sadly we can't just reject this in the template definition because it4113    // could be valid if the pack is empty or has exactly one expansion.4114    if (D->getDeclContext()->isFunctionOrMethod() && *NumExpansions > 1) {4115      SemaRef.Diag(D->getEllipsisLoc(),4116                   diag::err_using_decl_redeclaration_expansion);4117      return nullptr;4118    }4119 4120    // Instantiate the slices of this pack and build a UsingPackDecl.4121    SmallVector<NamedDecl*, 8> Expansions;4122    for (unsigned I = 0; I != *NumExpansions; ++I) {4123      Sema::ArgPackSubstIndexRAII SubstIndex(SemaRef, I);4124      Decl *Slice = instantiateUnresolvedUsingDecl(D, true);4125      if (!Slice)4126        return nullptr;4127      // Note that we can still get unresolved using declarations here, if we4128      // had arguments for all packs but the pattern also contained other4129      // template arguments (this only happens during partial substitution, eg4130      // into the body of a generic lambda in a function template).4131      Expansions.push_back(cast<NamedDecl>(Slice));4132    }4133 4134    auto *NewD = SemaRef.BuildUsingPackDecl(D, Expansions);4135    if (isDeclWithinFunction(D))4136      SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewD);4137    return NewD;4138  }4139 4140  UnresolvedUsingTypenameDecl *TD = dyn_cast<UnresolvedUsingTypenameDecl>(D);4141  SourceLocation TypenameLoc = TD ? TD->getTypenameLoc() : SourceLocation();4142 4143  NestedNameSpecifierLoc QualifierLoc4144    = SemaRef.SubstNestedNameSpecifierLoc(D->getQualifierLoc(),4145                                          TemplateArgs);4146  if (!QualifierLoc)4147    return nullptr;4148 4149  CXXScopeSpec SS;4150  SS.Adopt(QualifierLoc);4151 4152  DeclarationNameInfo NameInfo4153    = SemaRef.SubstDeclarationNameInfo(D->getNameInfo(), TemplateArgs);4154 4155  // Produce a pack expansion only if we're not instantiating a particular4156  // slice of a pack expansion.4157  bool InstantiatingSlice =4158      D->getEllipsisLoc().isValid() && SemaRef.ArgPackSubstIndex;4159  SourceLocation EllipsisLoc =4160      InstantiatingSlice ? SourceLocation() : D->getEllipsisLoc();4161 4162  bool IsUsingIfExists = D->template hasAttr<UsingIfExistsAttr>();4163  NamedDecl *UD = SemaRef.BuildUsingDeclaration(4164      /*Scope*/ nullptr, D->getAccess(), D->getUsingLoc(),4165      /*HasTypename*/ TD, TypenameLoc, SS, NameInfo, EllipsisLoc,4166      ParsedAttributesView(),4167      /*IsInstantiation*/ true, IsUsingIfExists);4168  if (UD) {4169    SemaRef.InstantiateAttrs(TemplateArgs, D, UD);4170    SemaRef.Context.setInstantiatedFromUsingDecl(UD, D);4171  }4172 4173  return UD;4174}4175 4176Decl *TemplateDeclInstantiator::VisitUnresolvedUsingTypenameDecl(4177    UnresolvedUsingTypenameDecl *D) {4178  return instantiateUnresolvedUsingDecl(D);4179}4180 4181Decl *TemplateDeclInstantiator::VisitUnresolvedUsingValueDecl(4182    UnresolvedUsingValueDecl *D) {4183  return instantiateUnresolvedUsingDecl(D);4184}4185 4186Decl *TemplateDeclInstantiator::VisitUnresolvedUsingIfExistsDecl(4187    UnresolvedUsingIfExistsDecl *D) {4188  llvm_unreachable("referring to unresolved decl out of UsingShadowDecl");4189}4190 4191Decl *TemplateDeclInstantiator::VisitUsingPackDecl(UsingPackDecl *D) {4192  SmallVector<NamedDecl*, 8> Expansions;4193  for (auto *UD : D->expansions()) {4194    if (NamedDecl *NewUD =4195            SemaRef.FindInstantiatedDecl(D->getLocation(), UD, TemplateArgs))4196      Expansions.push_back(NewUD);4197    else4198      return nullptr;4199  }4200 4201  auto *NewD = SemaRef.BuildUsingPackDecl(D, Expansions);4202  if (isDeclWithinFunction(D))4203    SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewD);4204  return NewD;4205}4206 4207Decl *TemplateDeclInstantiator::VisitOMPThreadPrivateDecl(4208                                     OMPThreadPrivateDecl *D) {4209  SmallVector<Expr *, 5> Vars;4210  for (auto *I : D->varlist()) {4211    Expr *Var = SemaRef.SubstExpr(I, TemplateArgs).get();4212    assert(isa<DeclRefExpr>(Var) && "threadprivate arg is not a DeclRefExpr");4213    Vars.push_back(Var);4214  }4215 4216  OMPThreadPrivateDecl *TD =4217      SemaRef.OpenMP().CheckOMPThreadPrivateDecl(D->getLocation(), Vars);4218 4219  TD->setAccess(AS_public);4220  Owner->addDecl(TD);4221 4222  return TD;4223}4224 4225Decl *4226TemplateDeclInstantiator::VisitOMPGroupPrivateDecl(OMPGroupPrivateDecl *D) {4227  SmallVector<Expr *, 5> Vars;4228  for (auto *I : D->varlist()) {4229    Expr *Var = SemaRef.SubstExpr(I, TemplateArgs).get();4230    assert(isa<DeclRefExpr>(Var) && "groupprivate arg is not a DeclRefExpr");4231    Vars.push_back(Var);4232  }4233 4234  OMPGroupPrivateDecl *TD =4235      SemaRef.OpenMP().CheckOMPGroupPrivateDecl(D->getLocation(), Vars);4236 4237  TD->setAccess(AS_public);4238  Owner->addDecl(TD);4239 4240  return TD;4241}4242 4243Decl *TemplateDeclInstantiator::VisitOMPAllocateDecl(OMPAllocateDecl *D) {4244  SmallVector<Expr *, 5> Vars;4245  for (auto *I : D->varlist()) {4246    Expr *Var = SemaRef.SubstExpr(I, TemplateArgs).get();4247    assert(isa<DeclRefExpr>(Var) && "allocate arg is not a DeclRefExpr");4248    Vars.push_back(Var);4249  }4250  SmallVector<OMPClause *, 4> Clauses;4251  // Copy map clauses from the original mapper.4252  for (OMPClause *C : D->clauselists()) {4253    OMPClause *IC = nullptr;4254    if (auto *AC = dyn_cast<OMPAllocatorClause>(C)) {4255      ExprResult NewE = SemaRef.SubstExpr(AC->getAllocator(), TemplateArgs);4256      if (!NewE.isUsable())4257        continue;4258      IC = SemaRef.OpenMP().ActOnOpenMPAllocatorClause(4259          NewE.get(), AC->getBeginLoc(), AC->getLParenLoc(), AC->getEndLoc());4260    } else if (auto *AC = dyn_cast<OMPAlignClause>(C)) {4261      ExprResult NewE = SemaRef.SubstExpr(AC->getAlignment(), TemplateArgs);4262      if (!NewE.isUsable())4263        continue;4264      IC = SemaRef.OpenMP().ActOnOpenMPAlignClause(4265          NewE.get(), AC->getBeginLoc(), AC->getLParenLoc(), AC->getEndLoc());4266      // If align clause value ends up being invalid, this can end up null.4267      if (!IC)4268        continue;4269    }4270    Clauses.push_back(IC);4271  }4272 4273  Sema::DeclGroupPtrTy Res = SemaRef.OpenMP().ActOnOpenMPAllocateDirective(4274      D->getLocation(), Vars, Clauses, Owner);4275  if (Res.get().isNull())4276    return nullptr;4277  return Res.get().getSingleDecl();4278}4279 4280Decl *TemplateDeclInstantiator::VisitOMPRequiresDecl(OMPRequiresDecl *D) {4281  llvm_unreachable(4282      "Requires directive cannot be instantiated within a dependent context");4283}4284 4285Decl *TemplateDeclInstantiator::VisitOMPDeclareReductionDecl(4286    OMPDeclareReductionDecl *D) {4287  // Instantiate type and check if it is allowed.4288  const bool RequiresInstantiation =4289      D->getType()->isDependentType() ||4290      D->getType()->isInstantiationDependentType() ||4291      D->getType()->containsUnexpandedParameterPack();4292  QualType SubstReductionType;4293  if (RequiresInstantiation) {4294    SubstReductionType = SemaRef.OpenMP().ActOnOpenMPDeclareReductionType(4295        D->getLocation(),4296        ParsedType::make(SemaRef.SubstType(4297            D->getType(), TemplateArgs, D->getLocation(), DeclarationName())));4298  } else {4299    SubstReductionType = D->getType();4300  }4301  if (SubstReductionType.isNull())4302    return nullptr;4303  Expr *Combiner = D->getCombiner();4304  Expr *Init = D->getInitializer();4305  bool IsCorrect = true;4306  // Create instantiated copy.4307  std::pair<QualType, SourceLocation> ReductionTypes[] = {4308      std::make_pair(SubstReductionType, D->getLocation())};4309  auto *PrevDeclInScope = D->getPrevDeclInScope();4310  if (PrevDeclInScope && !PrevDeclInScope->isInvalidDecl()) {4311    PrevDeclInScope = cast<OMPDeclareReductionDecl>(4312        cast<Decl *>(*SemaRef.CurrentInstantiationScope->findInstantiationOf(4313            PrevDeclInScope)));4314  }4315  auto DRD = SemaRef.OpenMP().ActOnOpenMPDeclareReductionDirectiveStart(4316      /*S=*/nullptr, Owner, D->getDeclName(), ReductionTypes, D->getAccess(),4317      PrevDeclInScope);4318  auto *NewDRD = cast<OMPDeclareReductionDecl>(DRD.get().getSingleDecl());4319  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewDRD);4320  Expr *SubstCombiner = nullptr;4321  Expr *SubstInitializer = nullptr;4322  // Combiners instantiation sequence.4323  if (Combiner) {4324    SemaRef.OpenMP().ActOnOpenMPDeclareReductionCombinerStart(4325        /*S=*/nullptr, NewDRD);4326    SemaRef.CurrentInstantiationScope->InstantiatedLocal(4327        cast<DeclRefExpr>(D->getCombinerIn())->getDecl(),4328        cast<DeclRefExpr>(NewDRD->getCombinerIn())->getDecl());4329    SemaRef.CurrentInstantiationScope->InstantiatedLocal(4330        cast<DeclRefExpr>(D->getCombinerOut())->getDecl(),4331        cast<DeclRefExpr>(NewDRD->getCombinerOut())->getDecl());4332    auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(Owner);4333    Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, Qualifiers(),4334                                     ThisContext);4335    SubstCombiner = SemaRef.SubstExpr(Combiner, TemplateArgs).get();4336    SemaRef.OpenMP().ActOnOpenMPDeclareReductionCombinerEnd(NewDRD,4337                                                            SubstCombiner);4338  }4339  // Initializers instantiation sequence.4340  if (Init) {4341    VarDecl *OmpPrivParm =4342        SemaRef.OpenMP().ActOnOpenMPDeclareReductionInitializerStart(4343            /*S=*/nullptr, NewDRD);4344    SemaRef.CurrentInstantiationScope->InstantiatedLocal(4345        cast<DeclRefExpr>(D->getInitOrig())->getDecl(),4346        cast<DeclRefExpr>(NewDRD->getInitOrig())->getDecl());4347    SemaRef.CurrentInstantiationScope->InstantiatedLocal(4348        cast<DeclRefExpr>(D->getInitPriv())->getDecl(),4349        cast<DeclRefExpr>(NewDRD->getInitPriv())->getDecl());4350    if (D->getInitializerKind() == OMPDeclareReductionInitKind::Call) {4351      SubstInitializer = SemaRef.SubstExpr(Init, TemplateArgs).get();4352    } else {4353      auto *OldPrivParm =4354          cast<VarDecl>(cast<DeclRefExpr>(D->getInitPriv())->getDecl());4355      IsCorrect = IsCorrect && OldPrivParm->hasInit();4356      if (IsCorrect)4357        SemaRef.InstantiateVariableInitializer(OmpPrivParm, OldPrivParm,4358                                               TemplateArgs);4359    }4360    SemaRef.OpenMP().ActOnOpenMPDeclareReductionInitializerEnd(4361        NewDRD, SubstInitializer, OmpPrivParm);4362  }4363  IsCorrect = IsCorrect && SubstCombiner &&4364              (!Init ||4365               (D->getInitializerKind() == OMPDeclareReductionInitKind::Call &&4366                SubstInitializer) ||4367               (D->getInitializerKind() != OMPDeclareReductionInitKind::Call &&4368                !SubstInitializer));4369 4370  (void)SemaRef.OpenMP().ActOnOpenMPDeclareReductionDirectiveEnd(4371      /*S=*/nullptr, DRD, IsCorrect && !D->isInvalidDecl());4372 4373  return NewDRD;4374}4375 4376Decl *4377TemplateDeclInstantiator::VisitOMPDeclareMapperDecl(OMPDeclareMapperDecl *D) {4378  // Instantiate type and check if it is allowed.4379  const bool RequiresInstantiation =4380      D->getType()->isDependentType() ||4381      D->getType()->isInstantiationDependentType() ||4382      D->getType()->containsUnexpandedParameterPack();4383  QualType SubstMapperTy;4384  DeclarationName VN = D->getVarName();4385  if (RequiresInstantiation) {4386    SubstMapperTy = SemaRef.OpenMP().ActOnOpenMPDeclareMapperType(4387        D->getLocation(),4388        ParsedType::make(SemaRef.SubstType(D->getType(), TemplateArgs,4389                                           D->getLocation(), VN)));4390  } else {4391    SubstMapperTy = D->getType();4392  }4393  if (SubstMapperTy.isNull())4394    return nullptr;4395  // Create an instantiated copy of mapper.4396  auto *PrevDeclInScope = D->getPrevDeclInScope();4397  if (PrevDeclInScope && !PrevDeclInScope->isInvalidDecl()) {4398    PrevDeclInScope = cast<OMPDeclareMapperDecl>(4399        cast<Decl *>(*SemaRef.CurrentInstantiationScope->findInstantiationOf(4400            PrevDeclInScope)));4401  }4402  bool IsCorrect = true;4403  SmallVector<OMPClause *, 6> Clauses;4404  // Instantiate the mapper variable.4405  DeclarationNameInfo DirName;4406  SemaRef.OpenMP().StartOpenMPDSABlock(llvm::omp::OMPD_declare_mapper, DirName,4407                                       /*S=*/nullptr,4408                                       (*D->clauselist_begin())->getBeginLoc());4409  ExprResult MapperVarRef =4410      SemaRef.OpenMP().ActOnOpenMPDeclareMapperDirectiveVarDecl(4411          /*S=*/nullptr, SubstMapperTy, D->getLocation(), VN);4412  SemaRef.CurrentInstantiationScope->InstantiatedLocal(4413      cast<DeclRefExpr>(D->getMapperVarRef())->getDecl(),4414      cast<DeclRefExpr>(MapperVarRef.get())->getDecl());4415  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(Owner);4416  Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, Qualifiers(),4417                                   ThisContext);4418  // Instantiate map clauses.4419  for (OMPClause *C : D->clauselists()) {4420    auto *OldC = cast<OMPMapClause>(C);4421    SmallVector<Expr *, 4> NewVars;4422    for (Expr *OE : OldC->varlist()) {4423      Expr *NE = SemaRef.SubstExpr(OE, TemplateArgs).get();4424      if (!NE) {4425        IsCorrect = false;4426        break;4427      }4428      NewVars.push_back(NE);4429    }4430    if (!IsCorrect)4431      break;4432    NestedNameSpecifierLoc NewQualifierLoc =4433        SemaRef.SubstNestedNameSpecifierLoc(OldC->getMapperQualifierLoc(),4434                                            TemplateArgs);4435    CXXScopeSpec SS;4436    SS.Adopt(NewQualifierLoc);4437    DeclarationNameInfo NewNameInfo =4438        SemaRef.SubstDeclarationNameInfo(OldC->getMapperIdInfo(), TemplateArgs);4439    OMPVarListLocTy Locs(OldC->getBeginLoc(), OldC->getLParenLoc(),4440                         OldC->getEndLoc());4441    OMPClause *NewC = SemaRef.OpenMP().ActOnOpenMPMapClause(4442        OldC->getIteratorModifier(), OldC->getMapTypeModifiers(),4443        OldC->getMapTypeModifiersLoc(), SS, NewNameInfo, OldC->getMapType(),4444        OldC->isImplicitMapType(), OldC->getMapLoc(), OldC->getColonLoc(),4445        NewVars, Locs);4446    Clauses.push_back(NewC);4447  }4448  SemaRef.OpenMP().EndOpenMPDSABlock(nullptr);4449  if (!IsCorrect)4450    return nullptr;4451  Sema::DeclGroupPtrTy DG = SemaRef.OpenMP().ActOnOpenMPDeclareMapperDirective(4452      /*S=*/nullptr, Owner, D->getDeclName(), SubstMapperTy, D->getLocation(),4453      VN, D->getAccess(), MapperVarRef.get(), Clauses, PrevDeclInScope);4454  Decl *NewDMD = DG.get().getSingleDecl();4455  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewDMD);4456  return NewDMD;4457}4458 4459Decl *TemplateDeclInstantiator::VisitOMPCapturedExprDecl(4460    OMPCapturedExprDecl * /*D*/) {4461  llvm_unreachable("Should not be met in templates");4462}4463 4464Decl *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D) {4465  return VisitFunctionDecl(D, nullptr);4466}4467 4468Decl *4469TemplateDeclInstantiator::VisitCXXDeductionGuideDecl(CXXDeductionGuideDecl *D) {4470  Decl *Inst = VisitFunctionDecl(D, nullptr);4471  if (Inst && !D->getDescribedFunctionTemplate())4472    Owner->addDecl(Inst);4473  return Inst;4474}4475 4476Decl *TemplateDeclInstantiator::VisitCXXMethodDecl(CXXMethodDecl *D) {4477  return VisitCXXMethodDecl(D, nullptr);4478}4479 4480Decl *TemplateDeclInstantiator::VisitRecordDecl(RecordDecl *D) {4481  llvm_unreachable("There are only CXXRecordDecls in C++");4482}4483 4484Decl *4485TemplateDeclInstantiator::VisitClassTemplateSpecializationDecl(4486    ClassTemplateSpecializationDecl *D) {4487  // As a MS extension, we permit class-scope explicit specialization4488  // of member class templates.4489  ClassTemplateDecl *ClassTemplate = D->getSpecializedTemplate();4490  assert(ClassTemplate->getDeclContext()->isRecord() &&4491         D->getTemplateSpecializationKind() == TSK_ExplicitSpecialization &&4492         "can only instantiate an explicit specialization "4493         "for a member class template");4494 4495  // Lookup the already-instantiated declaration in the instantiation4496  // of the class template.4497  ClassTemplateDecl *InstClassTemplate =4498      cast_or_null<ClassTemplateDecl>(SemaRef.FindInstantiatedDecl(4499          D->getLocation(), ClassTemplate, TemplateArgs));4500  if (!InstClassTemplate)4501    return nullptr;4502 4503  // Substitute into the template arguments of the class template explicit4504  // specialization.4505  TemplateArgumentListInfo InstTemplateArgs;4506  if (const ASTTemplateArgumentListInfo *TemplateArgsInfo =4507          D->getTemplateArgsAsWritten()) {4508    InstTemplateArgs.setLAngleLoc(TemplateArgsInfo->getLAngleLoc());4509    InstTemplateArgs.setRAngleLoc(TemplateArgsInfo->getRAngleLoc());4510 4511    if (SemaRef.SubstTemplateArguments(TemplateArgsInfo->arguments(),4512                                       TemplateArgs, InstTemplateArgs))4513      return nullptr;4514  }4515 4516  // Check that the template argument list is well-formed for this4517  // class template.4518  Sema::CheckTemplateArgumentInfo CTAI;4519  if (SemaRef.CheckTemplateArgumentList(4520          InstClassTemplate, D->getLocation(), InstTemplateArgs,4521          /*DefaultArgs=*/{}, /*PartialTemplateArgs=*/false, CTAI,4522          /*UpdateArgsWithConversions=*/true))4523    return nullptr;4524 4525  // Figure out where to insert this class template explicit specialization4526  // in the member template's set of class template explicit specializations.4527  void *InsertPos = nullptr;4528  ClassTemplateSpecializationDecl *PrevDecl =4529      InstClassTemplate->findSpecialization(CTAI.CanonicalConverted, InsertPos);4530 4531  // Check whether we've already seen a conflicting instantiation of this4532  // declaration (for instance, if there was a prior implicit instantiation).4533  bool Ignored;4534  if (PrevDecl &&4535      SemaRef.CheckSpecializationInstantiationRedecl(D->getLocation(),4536                                                     D->getSpecializationKind(),4537                                                     PrevDecl,4538                                                     PrevDecl->getSpecializationKind(),4539                                                     PrevDecl->getPointOfInstantiation(),4540                                                     Ignored))4541    return nullptr;4542 4543  // If PrevDecl was a definition and D is also a definition, diagnose.4544  // This happens in cases like:4545  //4546  //   template<typename T, typename U>4547  //   struct Outer {4548  //     template<typename X> struct Inner;4549  //     template<> struct Inner<T> {};4550  //     template<> struct Inner<U> {};4551  //   };4552  //4553  //   Outer<int, int> outer; // error: the explicit specializations of Inner4554  //                          // have the same signature.4555  if (PrevDecl && PrevDecl->getDefinition() &&4556      D->isThisDeclarationADefinition()) {4557    SemaRef.Diag(D->getLocation(), diag::err_redefinition) << PrevDecl;4558    SemaRef.Diag(PrevDecl->getDefinition()->getLocation(),4559                 diag::note_previous_definition);4560    return nullptr;4561  }4562 4563  // Create the class template partial specialization declaration.4564  ClassTemplateSpecializationDecl *InstD =4565      ClassTemplateSpecializationDecl::Create(4566          SemaRef.Context, D->getTagKind(), Owner, D->getBeginLoc(),4567          D->getLocation(), InstClassTemplate, CTAI.CanonicalConverted,4568          CTAI.StrictPackMatch, PrevDecl);4569  InstD->setTemplateArgsAsWritten(InstTemplateArgs);4570 4571  // Add this partial specialization to the set of class template partial4572  // specializations.4573  if (!PrevDecl)4574    InstClassTemplate->AddSpecialization(InstD, InsertPos);4575 4576  // Substitute the nested name specifier, if any.4577  if (SubstQualifier(D, InstD))4578    return nullptr;4579 4580  InstD->setAccess(D->getAccess());4581  InstD->setInstantiationOfMemberClass(D, TSK_ImplicitInstantiation);4582  InstD->setSpecializationKind(D->getSpecializationKind());4583  InstD->setExternKeywordLoc(D->getExternKeywordLoc());4584  InstD->setTemplateKeywordLoc(D->getTemplateKeywordLoc());4585 4586  Owner->addDecl(InstD);4587 4588  // Instantiate the members of the class-scope explicit specialization eagerly.4589  // We don't have support for lazy instantiation of an explicit specialization4590  // yet, and MSVC eagerly instantiates in this case.4591  // FIXME: This is wrong in standard C++.4592  if (D->isThisDeclarationADefinition() &&4593      SemaRef.InstantiateClass(D->getLocation(), InstD, D, TemplateArgs,4594                               TSK_ImplicitInstantiation,4595                               /*Complain=*/true))4596    return nullptr;4597 4598  return InstD;4599}4600 4601Decl *TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(4602    VarTemplateSpecializationDecl *D) {4603 4604  TemplateArgumentListInfo VarTemplateArgsInfo;4605  VarTemplateDecl *VarTemplate = D->getSpecializedTemplate();4606  assert(VarTemplate &&4607         "A template specialization without specialized template?");4608 4609  VarTemplateDecl *InstVarTemplate =4610      cast_or_null<VarTemplateDecl>(SemaRef.FindInstantiatedDecl(4611          D->getLocation(), VarTemplate, TemplateArgs));4612  if (!InstVarTemplate)4613    return nullptr;4614 4615  // Substitute the current template arguments.4616  if (const ASTTemplateArgumentListInfo *TemplateArgsInfo =4617          D->getTemplateArgsAsWritten()) {4618    VarTemplateArgsInfo.setLAngleLoc(TemplateArgsInfo->getLAngleLoc());4619    VarTemplateArgsInfo.setRAngleLoc(TemplateArgsInfo->getRAngleLoc());4620 4621    if (SemaRef.SubstTemplateArguments(TemplateArgsInfo->arguments(),4622                                       TemplateArgs, VarTemplateArgsInfo))4623      return nullptr;4624  }4625 4626  // Check that the template argument list is well-formed for this template.4627  Sema::CheckTemplateArgumentInfo CTAI;4628  if (SemaRef.CheckTemplateArgumentList(4629          InstVarTemplate, D->getLocation(), VarTemplateArgsInfo,4630          /*DefaultArgs=*/{}, /*PartialTemplateArgs=*/false, CTAI,4631          /*UpdateArgsWithConversions=*/true))4632    return nullptr;4633 4634  // Check whether we've already seen a declaration of this specialization.4635  void *InsertPos = nullptr;4636  VarTemplateSpecializationDecl *PrevDecl =4637      InstVarTemplate->findSpecialization(CTAI.CanonicalConverted, InsertPos);4638 4639  // Check whether we've already seen a conflicting instantiation of this4640  // declaration (for instance, if there was a prior implicit instantiation).4641  bool Ignored;4642  if (PrevDecl && SemaRef.CheckSpecializationInstantiationRedecl(4643                      D->getLocation(), D->getSpecializationKind(), PrevDecl,4644                      PrevDecl->getSpecializationKind(),4645                      PrevDecl->getPointOfInstantiation(), Ignored))4646    return nullptr;4647 4648  if (VarTemplateSpecializationDecl *VTSD = VisitVarTemplateSpecializationDecl(4649          InstVarTemplate, D, CTAI.CanonicalConverted, PrevDecl)) {4650    VTSD->setTemplateArgsAsWritten(VarTemplateArgsInfo);4651    return VTSD;4652  }4653  return nullptr;4654}4655 4656VarTemplateSpecializationDecl *4657TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(4658    VarTemplateDecl *VarTemplate, VarDecl *D,4659    ArrayRef<TemplateArgument> Converted,4660    VarTemplateSpecializationDecl *PrevDecl) {4661 4662  // Do substitution on the type of the declaration4663  TypeSourceInfo *TSI =4664      SemaRef.SubstType(D->getTypeSourceInfo(), TemplateArgs,4665                        D->getTypeSpecStartLoc(), D->getDeclName());4666  if (!TSI)4667    return nullptr;4668 4669  if (TSI->getType()->isFunctionType()) {4670    SemaRef.Diag(D->getLocation(), diag::err_variable_instantiates_to_function)4671        << D->isStaticDataMember() << TSI->getType();4672    return nullptr;4673  }4674 4675  // Build the instantiated declaration4676  VarTemplateSpecializationDecl *Var = VarTemplateSpecializationDecl::Create(4677      SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),4678      VarTemplate, TSI->getType(), TSI, D->getStorageClass(), Converted);4679  if (!PrevDecl) {4680    void *InsertPos = nullptr;4681    VarTemplate->findSpecialization(Converted, InsertPos);4682    VarTemplate->AddSpecialization(Var, InsertPos);4683  }4684 4685  if (SemaRef.getLangOpts().OpenCL)4686    SemaRef.deduceOpenCLAddressSpace(Var);4687 4688  // Substitute the nested name specifier, if any.4689  if (SubstQualifier(D, Var))4690    return nullptr;4691 4692  SemaRef.BuildVariableInstantiation(Var, D, TemplateArgs, LateAttrs, Owner,4693                                     StartingScope, false, PrevDecl);4694 4695  return Var;4696}4697 4698Decl *TemplateDeclInstantiator::VisitObjCAtDefsFieldDecl(ObjCAtDefsFieldDecl *D) {4699  llvm_unreachable("@defs is not supported in Objective-C++");4700}4701 4702Decl *TemplateDeclInstantiator::VisitFriendTemplateDecl(FriendTemplateDecl *D) {4703  // FIXME: We need to be able to instantiate FriendTemplateDecls.4704  unsigned DiagID = SemaRef.getDiagnostics().getCustomDiagID(4705                                               DiagnosticsEngine::Error,4706                                               "cannot instantiate %0 yet");4707  SemaRef.Diag(D->getLocation(), DiagID)4708    << D->getDeclKindName();4709 4710  return nullptr;4711}4712 4713Decl *TemplateDeclInstantiator::VisitConceptDecl(ConceptDecl *D) {4714  llvm_unreachable("Concept definitions cannot reside inside a template");4715}4716 4717Decl *TemplateDeclInstantiator::VisitImplicitConceptSpecializationDecl(4718    ImplicitConceptSpecializationDecl *D) {4719  llvm_unreachable("Concept specializations cannot reside inside a template");4720}4721 4722Decl *4723TemplateDeclInstantiator::VisitRequiresExprBodyDecl(RequiresExprBodyDecl *D) {4724  return RequiresExprBodyDecl::Create(SemaRef.Context, D->getDeclContext(),4725                                      D->getBeginLoc());4726}4727 4728Decl *TemplateDeclInstantiator::VisitDecl(Decl *D) {4729  llvm_unreachable("Unexpected decl");4730}4731 4732Decl *Sema::SubstDecl(Decl *D, DeclContext *Owner,4733                      const MultiLevelTemplateArgumentList &TemplateArgs) {4734  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);4735  if (D->isInvalidDecl())4736    return nullptr;4737 4738  Decl *SubstD;4739  runWithSufficientStackSpace(D->getLocation(), [&] {4740    SubstD = Instantiator.Visit(D);4741  });4742  return SubstD;4743}4744 4745void TemplateDeclInstantiator::adjustForRewrite(RewriteKind RK,4746                                                FunctionDecl *Orig, QualType &T,4747                                                TypeSourceInfo *&TInfo,4748                                                DeclarationNameInfo &NameInfo) {4749  assert(RK == RewriteKind::RewriteSpaceshipAsEqualEqual);4750 4751  // C++2a [class.compare.default]p3:4752  //   the return type is replaced with bool4753  auto *FPT = T->castAs<FunctionProtoType>();4754  T = SemaRef.Context.getFunctionType(4755      SemaRef.Context.BoolTy, FPT->getParamTypes(), FPT->getExtProtoInfo());4756 4757  // Update the return type in the source info too. The most straightforward4758  // way is to create new TypeSourceInfo for the new type. Use the location of4759  // the '= default' as the location of the new type.4760  //4761  // FIXME: Set the correct return type when we initially transform the type,4762  // rather than delaying it to now.4763  TypeSourceInfo *NewTInfo =4764      SemaRef.Context.getTrivialTypeSourceInfo(T, Orig->getEndLoc());4765  auto OldLoc = TInfo->getTypeLoc().getAsAdjusted<FunctionProtoTypeLoc>();4766  assert(OldLoc && "type of function is not a function type?");4767  auto NewLoc = NewTInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>();4768  for (unsigned I = 0, N = OldLoc.getNumParams(); I != N; ++I)4769    NewLoc.setParam(I, OldLoc.getParam(I));4770  TInfo = NewTInfo;4771 4772  //   and the declarator-id is replaced with operator==4773  NameInfo.setName(4774      SemaRef.Context.DeclarationNames.getCXXOperatorName(OO_EqualEqual));4775}4776 4777FunctionDecl *Sema::SubstSpaceshipAsEqualEqual(CXXRecordDecl *RD,4778                                               FunctionDecl *Spaceship) {4779  if (Spaceship->isInvalidDecl())4780    return nullptr;4781 4782  // C++2a [class.compare.default]p3:4783  //   an == operator function is declared implicitly [...] with the same4784  //   access and function-definition and in the same class scope as the4785  //   three-way comparison operator function4786  MultiLevelTemplateArgumentList NoTemplateArgs;4787  NoTemplateArgs.setKind(TemplateSubstitutionKind::Rewrite);4788  NoTemplateArgs.addOuterRetainedLevels(RD->getTemplateDepth());4789  TemplateDeclInstantiator Instantiator(*this, RD, NoTemplateArgs);4790  Decl *R;4791  if (auto *MD = dyn_cast<CXXMethodDecl>(Spaceship)) {4792    R = Instantiator.VisitCXXMethodDecl(4793        MD, /*TemplateParams=*/nullptr,4794        TemplateDeclInstantiator::RewriteKind::RewriteSpaceshipAsEqualEqual);4795  } else {4796    assert(Spaceship->getFriendObjectKind() &&4797           "defaulted spaceship is neither a member nor a friend");4798 4799    R = Instantiator.VisitFunctionDecl(4800        Spaceship, /*TemplateParams=*/nullptr,4801        TemplateDeclInstantiator::RewriteKind::RewriteSpaceshipAsEqualEqual);4802    if (!R)4803      return nullptr;4804 4805    FriendDecl *FD =4806        FriendDecl::Create(Context, RD, Spaceship->getLocation(),4807                           cast<NamedDecl>(R), Spaceship->getBeginLoc());4808    FD->setAccess(AS_public);4809    RD->addDecl(FD);4810  }4811  return cast_or_null<FunctionDecl>(R);4812}4813 4814/// Instantiates a nested template parameter list in the current4815/// instantiation context.4816///4817/// \param L The parameter list to instantiate4818///4819/// \returns NULL if there was an error4820TemplateParameterList *4821TemplateDeclInstantiator::SubstTemplateParams(TemplateParameterList *L) {4822  // Get errors for all the parameters before bailing out.4823  bool Invalid = false;4824 4825  unsigned N = L->size();4826  typedef SmallVector<NamedDecl *, 8> ParamVector;4827  ParamVector Params;4828  Params.reserve(N);4829  for (auto &P : *L) {4830    NamedDecl *D = cast_or_null<NamedDecl>(Visit(P));4831    Params.push_back(D);4832    Invalid = Invalid || !D || D->isInvalidDecl();4833  }4834 4835  // Clean up if we had an error.4836  if (Invalid)4837    return nullptr;4838 4839  Expr *InstRequiresClause = L->getRequiresClause();4840 4841  TemplateParameterList *InstL4842    = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(),4843                                    L->getLAngleLoc(), Params,4844                                    L->getRAngleLoc(), InstRequiresClause);4845  return InstL;4846}4847 4848TemplateParameterList *4849Sema::SubstTemplateParams(TemplateParameterList *Params, DeclContext *Owner,4850                          const MultiLevelTemplateArgumentList &TemplateArgs,4851                          bool EvaluateConstraints) {4852  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs);4853  Instantiator.setEvaluateConstraints(EvaluateConstraints);4854  return Instantiator.SubstTemplateParams(Params);4855}4856 4857/// Instantiate the declaration of a class template partial4858/// specialization.4859///4860/// \param ClassTemplate the (instantiated) class template that is partially4861// specialized by the instantiation of \p PartialSpec.4862///4863/// \param PartialSpec the (uninstantiated) class template partial4864/// specialization that we are instantiating.4865///4866/// \returns The instantiated partial specialization, if successful; otherwise,4867/// NULL to indicate an error.4868ClassTemplatePartialSpecializationDecl *4869TemplateDeclInstantiator::InstantiateClassTemplatePartialSpecialization(4870                                            ClassTemplateDecl *ClassTemplate,4871                          ClassTemplatePartialSpecializationDecl *PartialSpec) {4872  // Create a local instantiation scope for this class template partial4873  // specialization, which will contain the instantiations of the template4874  // parameters.4875  LocalInstantiationScope Scope(SemaRef);4876 4877  // Substitute into the template parameters of the class template partial4878  // specialization.4879  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();4880  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);4881  if (!InstParams)4882    return nullptr;4883 4884  // Substitute into the template arguments of the class template partial4885  // specialization.4886  const ASTTemplateArgumentListInfo *TemplArgInfo4887    = PartialSpec->getTemplateArgsAsWritten();4888  TemplateArgumentListInfo InstTemplateArgs(TemplArgInfo->LAngleLoc,4889                                            TemplArgInfo->RAngleLoc);4890  if (SemaRef.SubstTemplateArguments(TemplArgInfo->arguments(), TemplateArgs,4891                                     InstTemplateArgs))4892    return nullptr;4893 4894  // Check that the template argument list is well-formed for this4895  // class template.4896  Sema::CheckTemplateArgumentInfo CTAI;4897  if (SemaRef.CheckTemplateArgumentList(4898          ClassTemplate, PartialSpec->getLocation(), InstTemplateArgs,4899          /*DefaultArgs=*/{},4900          /*PartialTemplateArgs=*/false, CTAI))4901    return nullptr;4902 4903  // Check these arguments are valid for a template partial specialization.4904  if (SemaRef.CheckTemplatePartialSpecializationArgs(4905          PartialSpec->getLocation(), ClassTemplate, InstTemplateArgs.size(),4906          CTAI.CanonicalConverted))4907    return nullptr;4908 4909  // Figure out where to insert this class template partial specialization4910  // in the member template's set of class template partial specializations.4911  void *InsertPos = nullptr;4912  ClassTemplateSpecializationDecl *PrevDecl =4913      ClassTemplate->findPartialSpecialization(CTAI.CanonicalConverted,4914                                               InstParams, InsertPos);4915 4916  // Create the class template partial specialization declaration.4917  ClassTemplatePartialSpecializationDecl *InstPartialSpec =4918      ClassTemplatePartialSpecializationDecl::Create(4919          SemaRef.Context, PartialSpec->getTagKind(), Owner,4920          PartialSpec->getBeginLoc(), PartialSpec->getLocation(), InstParams,4921          ClassTemplate, CTAI.CanonicalConverted,4922          /*CanonInjectedTST=*/CanQualType(),4923          /*PrevDecl=*/nullptr);4924 4925  InstPartialSpec->setTemplateArgsAsWritten(InstTemplateArgs);4926 4927  // Substitute the nested name specifier, if any.4928  if (SubstQualifier(PartialSpec, InstPartialSpec))4929    return nullptr;4930 4931  InstPartialSpec->setInstantiatedFromMember(PartialSpec);4932 4933  if (PrevDecl) {4934    // We've already seen a partial specialization with the same template4935    // parameters and template arguments. This can happen, for example, when4936    // substituting the outer template arguments ends up causing two4937    // class template partial specializations of a member class template4938    // to have identical forms, e.g.,4939    //4940    //   template<typename T, typename U>4941    //   struct Outer {4942    //     template<typename X, typename Y> struct Inner;4943    //     template<typename Y> struct Inner<T, Y>;4944    //     template<typename Y> struct Inner<U, Y>;4945    //   };4946    //4947    //   Outer<int, int> outer; // error: the partial specializations of Inner4948    //                          // have the same signature.4949    SemaRef.Diag(InstPartialSpec->getLocation(),4950                 diag::err_partial_spec_redeclared)4951        << InstPartialSpec;4952    SemaRef.Diag(PrevDecl->getLocation(), diag::note_prev_partial_spec_here)4953        << SemaRef.Context.getCanonicalTagType(PrevDecl);4954    return nullptr;4955  }4956 4957  // Check the completed partial specialization.4958  SemaRef.CheckTemplatePartialSpecialization(InstPartialSpec);4959 4960  // Add this partial specialization to the set of class template partial4961  // specializations.4962  ClassTemplate->AddPartialSpecialization(InstPartialSpec,4963                                          /*InsertPos=*/nullptr);4964  return InstPartialSpec;4965}4966 4967/// Instantiate the declaration of a variable template partial4968/// specialization.4969///4970/// \param VarTemplate the (instantiated) variable template that is partially4971/// specialized by the instantiation of \p PartialSpec.4972///4973/// \param PartialSpec the (uninstantiated) variable template partial4974/// specialization that we are instantiating.4975///4976/// \returns The instantiated partial specialization, if successful; otherwise,4977/// NULL to indicate an error.4978VarTemplatePartialSpecializationDecl *4979TemplateDeclInstantiator::InstantiateVarTemplatePartialSpecialization(4980    VarTemplateDecl *VarTemplate,4981    VarTemplatePartialSpecializationDecl *PartialSpec) {4982  // Create a local instantiation scope for this variable template partial4983  // specialization, which will contain the instantiations of the template4984  // parameters.4985  LocalInstantiationScope Scope(SemaRef);4986 4987  // Substitute into the template parameters of the variable template partial4988  // specialization.4989  TemplateParameterList *TempParams = PartialSpec->getTemplateParameters();4990  TemplateParameterList *InstParams = SubstTemplateParams(TempParams);4991  if (!InstParams)4992    return nullptr;4993 4994  // Substitute into the template arguments of the variable template partial4995  // specialization.4996  const ASTTemplateArgumentListInfo *TemplArgInfo4997    = PartialSpec->getTemplateArgsAsWritten();4998  TemplateArgumentListInfo InstTemplateArgs(TemplArgInfo->LAngleLoc,4999                                            TemplArgInfo->RAngleLoc);5000  if (SemaRef.SubstTemplateArguments(TemplArgInfo->arguments(), TemplateArgs,5001                                     InstTemplateArgs))5002    return nullptr;5003 5004  // Check that the template argument list is well-formed for this5005  // class template.5006  Sema::CheckTemplateArgumentInfo CTAI;5007  if (SemaRef.CheckTemplateArgumentList(VarTemplate, PartialSpec->getLocation(),5008                                        InstTemplateArgs, /*DefaultArgs=*/{},5009                                        /*PartialTemplateArgs=*/false, CTAI))5010    return nullptr;5011 5012  // Check these arguments are valid for a template partial specialization.5013  if (SemaRef.CheckTemplatePartialSpecializationArgs(5014          PartialSpec->getLocation(), VarTemplate, InstTemplateArgs.size(),5015          CTAI.CanonicalConverted))5016    return nullptr;5017 5018  // Figure out where to insert this variable template partial specialization5019  // in the member template's set of variable template partial specializations.5020  void *InsertPos = nullptr;5021  VarTemplateSpecializationDecl *PrevDecl =5022      VarTemplate->findPartialSpecialization(CTAI.CanonicalConverted,5023                                             InstParams, InsertPos);5024 5025  // Do substitution on the type of the declaration5026  TypeSourceInfo *TSI = SemaRef.SubstType(5027      PartialSpec->getTypeSourceInfo(), TemplateArgs,5028      PartialSpec->getTypeSpecStartLoc(), PartialSpec->getDeclName());5029  if (!TSI)5030    return nullptr;5031 5032  if (TSI->getType()->isFunctionType()) {5033    SemaRef.Diag(PartialSpec->getLocation(),5034                 diag::err_variable_instantiates_to_function)5035        << PartialSpec->isStaticDataMember() << TSI->getType();5036    return nullptr;5037  }5038 5039  // Create the variable template partial specialization declaration.5040  VarTemplatePartialSpecializationDecl *InstPartialSpec =5041      VarTemplatePartialSpecializationDecl::Create(5042          SemaRef.Context, Owner, PartialSpec->getInnerLocStart(),5043          PartialSpec->getLocation(), InstParams, VarTemplate, TSI->getType(),5044          TSI, PartialSpec->getStorageClass(), CTAI.CanonicalConverted);5045 5046  InstPartialSpec->setTemplateArgsAsWritten(InstTemplateArgs);5047 5048  // Substitute the nested name specifier, if any.5049  if (SubstQualifier(PartialSpec, InstPartialSpec))5050    return nullptr;5051 5052  InstPartialSpec->setInstantiatedFromMember(PartialSpec);5053 5054  if (PrevDecl) {5055    // We've already seen a partial specialization with the same template5056    // parameters and template arguments. This can happen, for example, when5057    // substituting the outer template arguments ends up causing two5058    // variable template partial specializations of a member variable template5059    // to have identical forms, e.g.,5060    //5061    //   template<typename T, typename U>5062    //   struct Outer {5063    //     template<typename X, typename Y> pair<X,Y> p;5064    //     template<typename Y> pair<T, Y> p;5065    //     template<typename Y> pair<U, Y> p;5066    //   };5067    //5068    //   Outer<int, int> outer; // error: the partial specializations of Inner5069    //                          // have the same signature.5070    SemaRef.Diag(PartialSpec->getLocation(),5071                 diag::err_var_partial_spec_redeclared)5072        << InstPartialSpec;5073    SemaRef.Diag(PrevDecl->getLocation(),5074                 diag::note_var_prev_partial_spec_here);5075    return nullptr;5076  }5077  // Check the completed partial specialization.5078  SemaRef.CheckTemplatePartialSpecialization(InstPartialSpec);5079 5080  // Add this partial specialization to the set of variable template partial5081  // specializations. The instantiation of the initializer is not necessary.5082  VarTemplate->AddPartialSpecialization(InstPartialSpec, /*InsertPos=*/nullptr);5083 5084  SemaRef.BuildVariableInstantiation(InstPartialSpec, PartialSpec, TemplateArgs,5085                                     LateAttrs, Owner, StartingScope);5086 5087  return InstPartialSpec;5088}5089 5090TypeSourceInfo*5091TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D,5092                              SmallVectorImpl<ParmVarDecl *> &Params) {5093  TypeSourceInfo *OldTInfo = D->getTypeSourceInfo();5094  assert(OldTInfo && "substituting function without type source info");5095  assert(Params.empty() && "parameter vector is non-empty at start");5096 5097  CXXRecordDecl *ThisContext = nullptr;5098  Qualifiers ThisTypeQuals;5099  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {5100    ThisContext = cast<CXXRecordDecl>(Owner);5101    ThisTypeQuals = Method->getFunctionObjectParameterType().getQualifiers();5102  }5103 5104  TypeSourceInfo *NewTInfo = SemaRef.SubstFunctionDeclType(5105      OldTInfo, TemplateArgs, D->getTypeSpecStartLoc(), D->getDeclName(),5106      ThisContext, ThisTypeQuals, EvaluateConstraints);5107  if (!NewTInfo)5108    return nullptr;5109 5110  TypeLoc OldTL = OldTInfo->getTypeLoc().IgnoreParens();5111  if (FunctionProtoTypeLoc OldProtoLoc = OldTL.getAs<FunctionProtoTypeLoc>()) {5112    if (NewTInfo != OldTInfo) {5113      // Get parameters from the new type info.5114      TypeLoc NewTL = NewTInfo->getTypeLoc().IgnoreParens();5115      FunctionProtoTypeLoc NewProtoLoc = NewTL.castAs<FunctionProtoTypeLoc>();5116      unsigned NewIdx = 0;5117      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc.getNumParams();5118           OldIdx != NumOldParams; ++OldIdx) {5119        ParmVarDecl *OldParam = OldProtoLoc.getParam(OldIdx);5120        if (!OldParam)5121          return nullptr;5122 5123        LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;5124 5125        UnsignedOrNone NumArgumentsInExpansion = std::nullopt;5126        if (OldParam->isParameterPack())5127          NumArgumentsInExpansion =5128              SemaRef.getNumArgumentsInExpansion(OldParam->getType(),5129                                                 TemplateArgs);5130        if (!NumArgumentsInExpansion) {5131          // Simple case: normal parameter, or a parameter pack that's5132          // instantiated to a (still-dependent) parameter pack.5133          ParmVarDecl *NewParam = NewProtoLoc.getParam(NewIdx++);5134          Params.push_back(NewParam);5135          Scope->InstantiatedLocal(OldParam, NewParam);5136        } else {5137          // Parameter pack expansion: make the instantiation an argument pack.5138          Scope->MakeInstantiatedLocalArgPack(OldParam);5139          for (unsigned I = 0; I != *NumArgumentsInExpansion; ++I) {5140            ParmVarDecl *NewParam = NewProtoLoc.getParam(NewIdx++);5141            Params.push_back(NewParam);5142            Scope->InstantiatedLocalPackArg(OldParam, NewParam);5143          }5144        }5145      }5146    } else {5147      // The function type itself was not dependent and therefore no5148      // substitution occurred. However, we still need to instantiate5149      // the function parameters themselves.5150      const FunctionProtoType *OldProto =5151          cast<FunctionProtoType>(OldProtoLoc.getType());5152      for (unsigned i = 0, i_end = OldProtoLoc.getNumParams(); i != i_end;5153           ++i) {5154        ParmVarDecl *OldParam = OldProtoLoc.getParam(i);5155        if (!OldParam) {5156          Params.push_back(SemaRef.BuildParmVarDeclForTypedef(5157              D, D->getLocation(), OldProto->getParamType(i)));5158          continue;5159        }5160 5161        ParmVarDecl *Parm =5162            cast_or_null<ParmVarDecl>(VisitParmVarDecl(OldParam));5163        if (!Parm)5164          return nullptr;5165        Params.push_back(Parm);5166      }5167    }5168  } else {5169    // If the type of this function, after ignoring parentheses, is not5170    // *directly* a function type, then we're instantiating a function that5171    // was declared via a typedef or with attributes, e.g.,5172    //5173    //   typedef int functype(int, int);5174    //   functype func;5175    //   int __cdecl meth(int, int);5176    //5177    // In this case, we'll just go instantiate the ParmVarDecls that we5178    // synthesized in the method declaration.5179    SmallVector<QualType, 4> ParamTypes;5180    Sema::ExtParameterInfoBuilder ExtParamInfos;5181    if (SemaRef.SubstParmTypes(D->getLocation(), D->parameters(), nullptr,5182                               TemplateArgs, ParamTypes, &Params,5183                               ExtParamInfos))5184      return nullptr;5185  }5186 5187  return NewTInfo;5188}5189 5190void Sema::addInstantiatedLocalVarsToScope(FunctionDecl *Function,5191                                           const FunctionDecl *PatternDecl,5192                                           LocalInstantiationScope &Scope) {5193  LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(getFunctionScopes().back());5194 5195  for (auto *decl : PatternDecl->decls()) {5196    if (!isa<VarDecl>(decl) || isa<ParmVarDecl>(decl))5197      continue;5198 5199    VarDecl *VD = cast<VarDecl>(decl);5200    IdentifierInfo *II = VD->getIdentifier();5201 5202    auto it = llvm::find_if(Function->decls(), [&](Decl *inst) {5203      VarDecl *InstVD = dyn_cast<VarDecl>(inst);5204      return InstVD && InstVD->isLocalVarDecl() &&5205             InstVD->getIdentifier() == II;5206    });5207 5208    if (it == Function->decls().end())5209      continue;5210 5211    Scope.InstantiatedLocal(VD, *it);5212    LSI->addCapture(cast<VarDecl>(*it), /*isBlock=*/false, /*isByref=*/false,5213                    /*isNested=*/false, VD->getLocation(), SourceLocation(),5214                    VD->getType(), /*Invalid=*/false);5215  }5216}5217 5218bool Sema::addInstantiatedParametersToScope(5219    FunctionDecl *Function, const FunctionDecl *PatternDecl,5220    LocalInstantiationScope &Scope,5221    const MultiLevelTemplateArgumentList &TemplateArgs) {5222  unsigned FParamIdx = 0;5223  for (unsigned I = 0, N = PatternDecl->getNumParams(); I != N; ++I) {5224    const ParmVarDecl *PatternParam = PatternDecl->getParamDecl(I);5225    if (!PatternParam->isParameterPack()) {5226      // Simple case: not a parameter pack.5227      assert(FParamIdx < Function->getNumParams());5228      ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);5229      FunctionParam->setDeclName(PatternParam->getDeclName());5230      // If the parameter's type is not dependent, update it to match the type5231      // in the pattern. They can differ in top-level cv-qualifiers, and we want5232      // the pattern's type here. If the type is dependent, they can't differ,5233      // per core issue 1668. Substitute into the type from the pattern, in case5234      // it's instantiation-dependent.5235      // FIXME: Updating the type to work around this is at best fragile.5236      if (!PatternDecl->getType()->isDependentType()) {5237        QualType T = SubstType(PatternParam->getType(), TemplateArgs,5238                               FunctionParam->getLocation(),5239                               FunctionParam->getDeclName());5240        if (T.isNull())5241          return true;5242        FunctionParam->setType(T);5243      }5244 5245      Scope.InstantiatedLocal(PatternParam, FunctionParam);5246      ++FParamIdx;5247      continue;5248    }5249 5250    // Expand the parameter pack.5251    Scope.MakeInstantiatedLocalArgPack(PatternParam);5252    UnsignedOrNone NumArgumentsInExpansion =5253        getNumArgumentsInExpansion(PatternParam->getType(), TemplateArgs);5254    if (NumArgumentsInExpansion) {5255      QualType PatternType =5256          PatternParam->getType()->castAs<PackExpansionType>()->getPattern();5257      for (unsigned Arg = 0; Arg < *NumArgumentsInExpansion; ++Arg) {5258        ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);5259        FunctionParam->setDeclName(PatternParam->getDeclName());5260        if (!PatternDecl->getType()->isDependentType()) {5261          Sema::ArgPackSubstIndexRAII SubstIndex(*this, Arg);5262          QualType T =5263              SubstType(PatternType, TemplateArgs, FunctionParam->getLocation(),5264                        FunctionParam->getDeclName());5265          if (T.isNull())5266            return true;5267          FunctionParam->setType(T);5268        }5269 5270        Scope.InstantiatedLocalPackArg(PatternParam, FunctionParam);5271        ++FParamIdx;5272      }5273    }5274  }5275 5276  return false;5277}5278 5279bool Sema::InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,5280                                      ParmVarDecl *Param) {5281  assert(Param->hasUninstantiatedDefaultArg());5282 5283  // FIXME: We don't track member specialization info for non-defining5284  // friend declarations, so we will not be able to later find the function5285  // pattern. As a workaround, don't instantiate the default argument in this5286  // case. This is correct per the standard and only an issue for recovery5287  // purposes. [dcl.fct.default]p4:5288  //   if a friend declaration D specifies a default argument expression,5289  //   that declaration shall be a definition.5290  if (FD->getFriendObjectKind() != Decl::FOK_None &&5291      !FD->getTemplateInstantiationPattern())5292    return true;5293 5294  // Instantiate the expression.5295  //5296  // FIXME: Pass in a correct Pattern argument, otherwise5297  // getTemplateInstantiationArgs uses the lexical context of FD, e.g.5298  //5299  // template<typename T>5300  // struct A {5301  //   static int FooImpl();5302  //5303  //   template<typename Tp>5304  //   // bug: default argument A<T>::FooImpl() is evaluated with 2-level5305  //   // template argument list [[T], [Tp]], should be [[Tp]].5306  //   friend A<Tp> Foo(int a);5307  // };5308  //5309  // template<typename T>5310  // A<T> Foo(int a = A<T>::FooImpl());5311  MultiLevelTemplateArgumentList TemplateArgs = getTemplateInstantiationArgs(5312      FD, FD->getLexicalDeclContext(),5313      /*Final=*/false, /*Innermost=*/std::nullopt,5314      /*RelativeToPrimary=*/true, /*Pattern=*/nullptr,5315      /*ForConstraintInstantiation=*/false, /*SkipForSpecialization=*/false,5316      /*ForDefaultArgumentSubstitution=*/true);5317 5318  if (SubstDefaultArgument(CallLoc, Param, TemplateArgs, /*ForCallExpr*/ true))5319    return true;5320 5321  if (ASTMutationListener *L = getASTMutationListener())5322    L->DefaultArgumentInstantiated(Param);5323 5324  return false;5325}5326 5327void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,5328                                    FunctionDecl *Decl) {5329  const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();5330  if (Proto->getExceptionSpecType() != EST_Uninstantiated)5331    return;5332 5333  RecursiveInstGuard AlreadyInstantiating(5334      *this, Decl, RecursiveInstGuard::Kind::ExceptionSpec);5335  if (AlreadyInstantiating) {5336    // This exception specification indirectly depends on itself. Reject.5337    // FIXME: Corresponding rule in the standard?5338    Diag(PointOfInstantiation, diag::err_exception_spec_cycle) << Decl;5339    UpdateExceptionSpec(Decl, EST_None);5340    return;5341  }5342 5343  NonSFINAEContext _(*this);5344  InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,5345                             InstantiatingTemplate::ExceptionSpecification());5346  if (Inst.isInvalid()) {5347    // We hit the instantiation depth limit. Clear the exception specification5348    // so that our callers don't have to cope with EST_Uninstantiated.5349    UpdateExceptionSpec(Decl, EST_None);5350    return;5351  }5352 5353  // Enter the scope of this instantiation. We don't use5354  // PushDeclContext because we don't have a scope.5355  Sema::ContextRAII savedContext(*this, Decl);5356  LocalInstantiationScope Scope(*this);5357 5358  MultiLevelTemplateArgumentList TemplateArgs =5359      getTemplateInstantiationArgs(Decl, Decl->getLexicalDeclContext(),5360                                   /*Final=*/false, /*Innermost=*/std::nullopt,5361                                   /*RelativeToPrimary*/ true);5362 5363  // FIXME: We can't use getTemplateInstantiationPattern(false) in general5364  // here, because for a non-defining friend declaration in a class template,5365  // we don't store enough information to map back to the friend declaration in5366  // the template.5367  FunctionDecl *Template = Proto->getExceptionSpecTemplate();5368  if (addInstantiatedParametersToScope(Decl, Template, Scope, TemplateArgs)) {5369    UpdateExceptionSpec(Decl, EST_None);5370    return;5371  }5372 5373  // The noexcept specification could reference any lambda captures. Ensure5374  // those are added to the LocalInstantiationScope.5375  LambdaScopeForCallOperatorInstantiationRAII PushLambdaCaptures(5376      *this, Decl, TemplateArgs, Scope,5377      /*ShouldAddDeclsFromParentScope=*/false);5378 5379  SubstExceptionSpec(Decl, Template->getType()->castAs<FunctionProtoType>(),5380                     TemplateArgs);5381}5382 5383/// Initializes the common fields of an instantiation function5384/// declaration (New) from the corresponding fields of its template (Tmpl).5385///5386/// \returns true if there was an error5387bool5388TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,5389                                                    FunctionDecl *Tmpl) {5390  New->setImplicit(Tmpl->isImplicit());5391 5392  // Forward the mangling number from the template to the instantiated decl.5393  SemaRef.Context.setManglingNumber(New,5394                                    SemaRef.Context.getManglingNumber(Tmpl));5395 5396  // If we are performing substituting explicitly-specified template arguments5397  // or deduced template arguments into a function template and we reach this5398  // point, we are now past the point where SFINAE applies and have committed5399  // to keeping the new function template specialization. We therefore5400  // convert the active template instantiation for the function template5401  // into a template instantiation for this specific function template5402  // specialization, which is not a SFINAE context, so that we diagnose any5403  // further errors in the declaration itself.5404  //5405  // FIXME: This is a hack.5406  typedef Sema::CodeSynthesisContext ActiveInstType;5407  ActiveInstType &ActiveInst = SemaRef.CodeSynthesisContexts.back();5408  if (ActiveInst.Kind == ActiveInstType::ExplicitTemplateArgumentSubstitution ||5409      ActiveInst.Kind == ActiveInstType::DeducedTemplateArgumentSubstitution) {5410    if (isa<FunctionTemplateDecl>(ActiveInst.Entity)) {5411      SemaRef.CurrentSFINAEContext = nullptr;5412      atTemplateEnd(SemaRef.TemplateInstCallbacks, SemaRef, ActiveInst);5413      ActiveInst.Kind = ActiveInstType::TemplateInstantiation;5414      ActiveInst.Entity = New;5415      atTemplateBegin(SemaRef.TemplateInstCallbacks, SemaRef, ActiveInst);5416    }5417  }5418 5419  const FunctionProtoType *Proto = Tmpl->getType()->getAs<FunctionProtoType>();5420  assert(Proto && "Function template without prototype?");5421 5422  if (Proto->hasExceptionSpec() || Proto->getNoReturnAttr()) {5423    FunctionProtoType::ExtProtoInfo EPI = Proto->getExtProtoInfo();5424 5425    // DR1330: In C++11, defer instantiation of a non-trivial5426    // exception specification.5427    // DR1484: Local classes and their members are instantiated along with the5428    // containing function.5429    if (SemaRef.getLangOpts().CPlusPlus11 &&5430        EPI.ExceptionSpec.Type != EST_None &&5431        EPI.ExceptionSpec.Type != EST_DynamicNone &&5432        EPI.ExceptionSpec.Type != EST_BasicNoexcept &&5433        !Tmpl->isInLocalScopeForInstantiation()) {5434      FunctionDecl *ExceptionSpecTemplate = Tmpl;5435      if (EPI.ExceptionSpec.Type == EST_Uninstantiated)5436        ExceptionSpecTemplate = EPI.ExceptionSpec.SourceTemplate;5437      ExceptionSpecificationType NewEST = EST_Uninstantiated;5438      if (EPI.ExceptionSpec.Type == EST_Unevaluated)5439        NewEST = EST_Unevaluated;5440 5441      // Mark the function has having an uninstantiated exception specification.5442      const FunctionProtoType *NewProto5443        = New->getType()->getAs<FunctionProtoType>();5444      assert(NewProto && "Template instantiation without function prototype?");5445      EPI = NewProto->getExtProtoInfo();5446      EPI.ExceptionSpec.Type = NewEST;5447      EPI.ExceptionSpec.SourceDecl = New;5448      EPI.ExceptionSpec.SourceTemplate = ExceptionSpecTemplate;5449      New->setType(SemaRef.Context.getFunctionType(5450          NewProto->getReturnType(), NewProto->getParamTypes(), EPI));5451    } else {5452      Sema::ContextRAII SwitchContext(SemaRef, New);5453      SemaRef.SubstExceptionSpec(New, Proto, TemplateArgs);5454    }5455  }5456 5457  // Get the definition. Leaves the variable unchanged if undefined.5458  const FunctionDecl *Definition = Tmpl;5459  Tmpl->isDefined(Definition);5460 5461  SemaRef.InstantiateAttrs(TemplateArgs, Definition, New,5462                           LateAttrs, StartingScope);5463 5464  return false;5465}5466 5467/// Initializes common fields of an instantiated method5468/// declaration (New) from the corresponding fields of its template5469/// (Tmpl).5470///5471/// \returns true if there was an error5472bool5473TemplateDeclInstantiator::InitMethodInstantiation(CXXMethodDecl *New,5474                                                  CXXMethodDecl *Tmpl) {5475  if (InitFunctionInstantiation(New, Tmpl))5476    return true;5477 5478  if (isa<CXXDestructorDecl>(New) && SemaRef.getLangOpts().CPlusPlus11)5479    SemaRef.AdjustDestructorExceptionSpec(cast<CXXDestructorDecl>(New));5480 5481  New->setAccess(Tmpl->getAccess());5482  if (Tmpl->isVirtualAsWritten())5483    New->setVirtualAsWritten(true);5484 5485  // FIXME: New needs a pointer to Tmpl5486  return false;5487}5488 5489bool TemplateDeclInstantiator::SubstDefaultedFunction(FunctionDecl *New,5490                                                      FunctionDecl *Tmpl) {5491  // Transfer across any unqualified lookups.5492  if (auto *DFI = Tmpl->getDefaultedOrDeletedInfo()) {5493    SmallVector<DeclAccessPair, 32> Lookups;5494    Lookups.reserve(DFI->getUnqualifiedLookups().size());5495    bool AnyChanged = false;5496    for (DeclAccessPair DA : DFI->getUnqualifiedLookups()) {5497      NamedDecl *D = SemaRef.FindInstantiatedDecl(New->getLocation(),5498                                                  DA.getDecl(), TemplateArgs);5499      if (!D)5500        return true;5501      AnyChanged |= (D != DA.getDecl());5502      Lookups.push_back(DeclAccessPair::make(D, DA.getAccess()));5503    }5504 5505    // It's unlikely that substitution will change any declarations. Don't5506    // store an unnecessary copy in that case.5507    New->setDefaultedOrDeletedInfo(5508        AnyChanged ? FunctionDecl::DefaultedOrDeletedFunctionInfo::Create(5509                         SemaRef.Context, Lookups)5510                   : DFI);5511  }5512 5513  SemaRef.SetDeclDefaulted(New, Tmpl->getLocation());5514  return false;5515}5516 5517FunctionDecl *Sema::InstantiateFunctionDeclaration(5518    FunctionTemplateDecl *FTD, const TemplateArgumentList *Args,5519    SourceLocation Loc, CodeSynthesisContext::SynthesisKind CSC) {5520  FunctionDecl *FD = FTD->getTemplatedDecl();5521 5522  InstantiatingTemplate Inst(*this, Loc, FTD, Args->asArray(), CSC);5523  if (Inst.isInvalid())5524    return nullptr;5525 5526  ContextRAII SavedContext(*this, FD);5527  MultiLevelTemplateArgumentList MArgs(FTD, Args->asArray(),5528                                       /*Final=*/false);5529 5530  return cast_or_null<FunctionDecl>(SubstDecl(FD, FD->getParent(), MArgs));5531}5532 5533void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,5534                                         FunctionDecl *Function,5535                                         bool Recursive,5536                                         bool DefinitionRequired,5537                                         bool AtEndOfTU) {5538  if (Function->isInvalidDecl() || isa<CXXDeductionGuideDecl>(Function))5539    return;5540 5541  // Never instantiate an explicit specialization except if it is a class scope5542  // explicit specialization.5543  TemplateSpecializationKind TSK =5544      Function->getTemplateSpecializationKindForInstantiation();5545  if (TSK == TSK_ExplicitSpecialization)5546    return;5547 5548  // Never implicitly instantiate a builtin; we don't actually need a function5549  // body.5550  if (Function->getBuiltinID() && TSK == TSK_ImplicitInstantiation &&5551      !DefinitionRequired)5552    return;5553 5554  // Don't instantiate a definition if we already have one.5555  const FunctionDecl *ExistingDefn = nullptr;5556  if (Function->isDefined(ExistingDefn,5557                          /*CheckForPendingFriendDefinition=*/true)) {5558    if (ExistingDefn->isThisDeclarationADefinition())5559      return;5560 5561    // If we're asked to instantiate a function whose body comes from an5562    // instantiated friend declaration, attach the instantiated body to the5563    // corresponding declaration of the function.5564    assert(ExistingDefn->isThisDeclarationInstantiatedFromAFriendDefinition());5565    Function = const_cast<FunctionDecl*>(ExistingDefn);5566  }5567 5568#ifndef NDEBUG5569  RecursiveInstGuard AlreadyInstantiating(*this, Function,5570                                          RecursiveInstGuard::Kind::Template);5571  assert(!AlreadyInstantiating && "should have been caught by caller");5572#endif5573 5574  // Find the function body that we'll be substituting.5575  const FunctionDecl *PatternDecl = Function->getTemplateInstantiationPattern();5576  assert(PatternDecl && "instantiating a non-template");5577 5578  const FunctionDecl *PatternDef = PatternDecl->getDefinition();5579  Stmt *Pattern = nullptr;5580  if (PatternDef) {5581    Pattern = PatternDef->getBody(PatternDef);5582    PatternDecl = PatternDef;5583    if (PatternDef->willHaveBody())5584      PatternDef = nullptr;5585  }5586 5587  // True is the template definition is unreachable, otherwise false.5588  bool Unreachable = false;5589  // FIXME: We need to track the instantiation stack in order to know which5590  // definitions should be visible within this instantiation.5591  if (DiagnoseUninstantiableTemplate(5592          PointOfInstantiation, Function,5593          Function->getInstantiatedFromMemberFunction(), PatternDecl,5594          PatternDef, TSK,5595          /*Complain*/ DefinitionRequired, &Unreachable)) {5596    if (DefinitionRequired)5597      Function->setInvalidDecl();5598    else if (TSK == TSK_ExplicitInstantiationDefinition ||5599             (Function->isConstexpr() && !Recursive)) {5600      // Try again at the end of the translation unit (at which point a5601      // definition will be required).5602      assert(!Recursive);5603      Function->setInstantiationIsPending(true);5604      PendingInstantiations.emplace_back(Function, PointOfInstantiation);5605 5606      if (llvm::isTimeTraceVerbose()) {5607        llvm::timeTraceAddInstantEvent("DeferInstantiation", [&] {5608          std::string Name;5609          llvm::raw_string_ostream OS(Name);5610          Function->getNameForDiagnostic(OS, getPrintingPolicy(),5611                                         /*Qualified=*/true);5612          return Name;5613        });5614      }5615    } else if (TSK == TSK_ImplicitInstantiation) {5616      if (AtEndOfTU && !getDiagnostics().hasErrorOccurred() &&5617          !getSourceManager().isInSystemHeader(PatternDecl->getBeginLoc())) {5618        Diag(PointOfInstantiation, diag::warn_func_template_missing)5619            << Function;5620        if (Unreachable) {5621          // FIXME: would be nice to mention which module the function template5622          // comes from.5623          Diag(PatternDecl->getLocation(),5624               diag::note_unreachable_template_decl);5625        } else {5626          Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);5627          if (getLangOpts().CPlusPlus11)5628            Diag(PointOfInstantiation, diag::note_inst_declaration_hint)5629                << Function;5630        }5631      }5632    }5633 5634    return;5635  }5636 5637  // Postpone late parsed template instantiations.5638  if (PatternDecl->isLateTemplateParsed() &&5639      !LateTemplateParser) {5640    Function->setInstantiationIsPending(true);5641    LateParsedInstantiations.push_back(5642        std::make_pair(Function, PointOfInstantiation));5643    return;5644  }5645 5646  llvm::TimeTraceScope TimeScope("InstantiateFunction", [&]() {5647    llvm::TimeTraceMetadata M;5648    llvm::raw_string_ostream OS(M.Detail);5649    Function->getNameForDiagnostic(OS, getPrintingPolicy(),5650                                   /*Qualified=*/true);5651    if (llvm::isTimeTraceVerbose()) {5652      auto Loc = SourceMgr.getExpansionLoc(Function->getLocation());5653      M.File = SourceMgr.getFilename(Loc);5654      M.Line = SourceMgr.getExpansionLineNumber(Loc);5655    }5656    return M;5657  });5658 5659  // If we're performing recursive template instantiation, create our own5660  // queue of pending implicit instantiations that we will instantiate later,5661  // while we're still within our own instantiation context.5662  // This has to happen before LateTemplateParser below is called, so that5663  // it marks vtables used in late parsed templates as used.5664  GlobalEagerInstantiationScope GlobalInstantiations(*this,5665                                                     /*Enabled=*/Recursive,5666                                                     /*AtEndOfTU=*/AtEndOfTU);5667  LocalEagerInstantiationScope LocalInstantiations(*this,5668                                                   /*AtEndOfTU=*/AtEndOfTU);5669 5670  // Call the LateTemplateParser callback if there is a need to late parse5671  // a templated function definition.5672  if (!Pattern && PatternDecl->isLateTemplateParsed() &&5673      LateTemplateParser) {5674    // FIXME: Optimize to allow individual templates to be deserialized.5675    if (PatternDecl->isFromASTFile())5676      ExternalSource->ReadLateParsedTemplates(LateParsedTemplateMap);5677 5678    auto LPTIter = LateParsedTemplateMap.find(PatternDecl);5679    assert(LPTIter != LateParsedTemplateMap.end() &&5680           "missing LateParsedTemplate");5681    LateTemplateParser(OpaqueParser, *LPTIter->second);5682    Pattern = PatternDecl->getBody(PatternDecl);5683    updateAttrsForLateParsedTemplate(PatternDecl, Function);5684  }5685 5686  // Note, we should never try to instantiate a deleted function template.5687  assert((Pattern || PatternDecl->isDefaulted() ||5688          PatternDecl->hasSkippedBody()) &&5689         "unexpected kind of function template definition");5690 5691  // C++1y [temp.explicit]p10:5692  //   Except for inline functions, declarations with types deduced from their5693  //   initializer or return value, and class template specializations, other5694  //   explicit instantiation declarations have the effect of suppressing the5695  //   implicit instantiation of the entity to which they refer.5696  if (TSK == TSK_ExplicitInstantiationDeclaration &&5697      !PatternDecl->isInlined() &&5698      !PatternDecl->getReturnType()->getContainedAutoType())5699    return;5700 5701  if (PatternDecl->isInlined()) {5702    // Function, and all later redeclarations of it (from imported modules,5703    // for instance), are now implicitly inline.5704    for (auto *D = Function->getMostRecentDecl(); /**/;5705         D = D->getPreviousDecl()) {5706      D->setImplicitlyInline();5707      if (D == Function)5708        break;5709    }5710  }5711 5712  NonSFINAEContext _(*this);5713  InstantiatingTemplate Inst(*this, PointOfInstantiation, Function);5714  if (Inst.isInvalid())5715    return;5716  PrettyDeclStackTraceEntry CrashInfo(Context, Function, SourceLocation(),5717                                      "instantiating function definition");5718 5719  // The instantiation is visible here, even if it was first declared in an5720  // unimported module.5721  Function->setVisibleDespiteOwningModule();5722 5723  // Copy the source locations from the pattern.5724  Function->setLocation(PatternDecl->getLocation());5725  Function->setInnerLocStart(PatternDecl->getInnerLocStart());5726  Function->setRangeEnd(PatternDecl->getEndLoc());5727  // Let the instantiation use the Pattern's DeclarationNameLoc, due to the5728  // following awkwardness:5729  //5730  //   1. There are out-of-tree users of getNameInfo().getSourceRange(), who5731  //   expect the source range of the instantiated declaration to be set to5732  //   point to the definition.5733  //5734  //   2. That getNameInfo().getSourceRange() might return the TypeLocInfo's5735  //   location it tracked.5736  //5737  //   3. Function might come from an (implicit) declaration, while the pattern5738  //   comes from a definition. In these cases, we need the PatternDecl's source5739  //   location.5740  //5741  // To that end, we need to more or less tweak the DeclarationNameLoc. However,5742  // we can't blindly copy the DeclarationNameLoc from the PatternDecl to the5743  // function, since it contains associated TypeLocs that should have already5744  // been transformed. So, we rebuild the TypeLoc for that purpose. Technically,5745  // we should create a new function declaration and assign everything we need,5746  // but InstantiateFunctionDefinition updates the declaration in place.5747  auto NameLocPointsToPattern = [&] {5748    DeclarationNameInfo PatternName = PatternDecl->getNameInfo();5749    DeclarationNameLoc PatternNameLoc = PatternName.getInfo();5750    switch (PatternName.getName().getNameKind()) {5751    case DeclarationName::CXXConstructorName:5752    case DeclarationName::CXXDestructorName:5753    case DeclarationName::CXXConversionFunctionName:5754      break;5755    default:5756      // Cases where DeclarationNameLoc doesn't matter, as it merely contains a5757      // source range.5758      return PatternNameLoc;5759    }5760 5761    TypeSourceInfo *TSI = Function->getNameInfo().getNamedTypeInfo();5762    // TSI might be null if the function is named by a constructor template id.5763    // E.g. S<T>() {} for class template S with a template parameter T.5764    if (!TSI) {5765      // We don't care about the DeclarationName of the instantiated function,5766      // but only the DeclarationNameLoc. So if the TypeLoc is absent, we do5767      // nothing.5768      return PatternNameLoc;5769    }5770 5771    QualType InstT = TSI->getType();5772    // We want to use a TypeLoc that reflects the transformed type while5773    // preserving the source location from the pattern.5774    TypeLocBuilder TLB;5775    TypeSourceInfo *PatternTSI = PatternName.getNamedTypeInfo();5776    assert(PatternTSI && "Pattern is supposed to have an associated TSI");5777    // FIXME: PatternTSI is not trivial. We should copy the source location5778    // along the TypeLoc chain. However a trivial TypeLoc is sufficient for5779    // getNameInfo().getSourceRange().5780    TLB.pushTrivial(Context, InstT, PatternTSI->getTypeLoc().getBeginLoc());5781    return DeclarationNameLoc::makeNamedTypeLoc(5782        TLB.getTypeSourceInfo(Context, InstT));5783  };5784  Function->setDeclarationNameLoc(NameLocPointsToPattern());5785 5786  EnterExpressionEvaluationContextForFunction EvalContext(5787      *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated, Function);5788 5789  Qualifiers ThisTypeQuals;5790  CXXRecordDecl *ThisContext = nullptr;5791  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {5792    ThisContext = Method->getParent();5793    ThisTypeQuals = Method->getMethodQualifiers();5794  }5795  CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals);5796 5797  // Introduce a new scope where local variable instantiations will be5798  // recorded, unless we're actually a member function within a local5799  // class, in which case we need to merge our results with the parent5800  // scope (of the enclosing function). The exception is instantiating5801  // a function template specialization, since the template to be5802  // instantiated already has references to locals properly substituted.5803  bool MergeWithParentScope = false;5804  if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))5805    MergeWithParentScope =5806        Rec->isLocalClass() && !Function->isFunctionTemplateSpecialization();5807 5808  LocalInstantiationScope Scope(*this, MergeWithParentScope);5809  auto RebuildTypeSourceInfoForDefaultSpecialMembers = [&]() {5810    // Special members might get their TypeSourceInfo set up w.r.t the5811    // PatternDecl context, in which case parameters could still be pointing5812    // back to the original class, make sure arguments are bound to the5813    // instantiated record instead.5814    assert(PatternDecl->isDefaulted() &&5815           "Special member needs to be defaulted");5816    auto PatternSM = getDefaultedFunctionKind(PatternDecl).asSpecialMember();5817    if (!(PatternSM == CXXSpecialMemberKind::CopyConstructor ||5818          PatternSM == CXXSpecialMemberKind::CopyAssignment ||5819          PatternSM == CXXSpecialMemberKind::MoveConstructor ||5820          PatternSM == CXXSpecialMemberKind::MoveAssignment))5821      return;5822 5823    auto *NewRec = dyn_cast<CXXRecordDecl>(Function->getDeclContext());5824    const auto *PatternRec =5825        dyn_cast<CXXRecordDecl>(PatternDecl->getDeclContext());5826    if (!NewRec || !PatternRec)5827      return;5828    if (!PatternRec->isLambda())5829      return;5830 5831    struct SpecialMemberTypeInfoRebuilder5832        : TreeTransform<SpecialMemberTypeInfoRebuilder> {5833      using Base = TreeTransform<SpecialMemberTypeInfoRebuilder>;5834      const CXXRecordDecl *OldDecl;5835      CXXRecordDecl *NewDecl;5836 5837      SpecialMemberTypeInfoRebuilder(Sema &SemaRef, const CXXRecordDecl *O,5838                                     CXXRecordDecl *N)5839          : TreeTransform(SemaRef), OldDecl(O), NewDecl(N) {}5840 5841      bool TransformExceptionSpec(SourceLocation Loc,5842                                  FunctionProtoType::ExceptionSpecInfo &ESI,5843                                  SmallVectorImpl<QualType> &Exceptions,5844                                  bool &Changed) {5845        return false;5846      }5847 5848      QualType TransformRecordType(TypeLocBuilder &TLB, RecordTypeLoc TL) {5849        const RecordType *T = TL.getTypePtr();5850        RecordDecl *Record = cast_or_null<RecordDecl>(5851            getDerived().TransformDecl(TL.getNameLoc(), T->getDecl()));5852        if (Record != OldDecl)5853          return Base::TransformRecordType(TLB, TL);5854 5855        // FIXME: transform the rest of the record type.5856        QualType Result = getDerived().RebuildTagType(5857            ElaboratedTypeKeyword::None, /*Qualifier=*/std::nullopt, NewDecl);5858        if (Result.isNull())5859          return QualType();5860 5861        TagTypeLoc NewTL = TLB.push<RecordTypeLoc>(Result);5862        NewTL.setElaboratedKeywordLoc(SourceLocation());5863        NewTL.setQualifierLoc(NestedNameSpecifierLoc());5864        NewTL.setNameLoc(TL.getNameLoc());5865        return Result;5866      }5867    } IR{*this, PatternRec, NewRec};5868 5869    TypeSourceInfo *NewSI = IR.TransformType(Function->getTypeSourceInfo());5870    assert(NewSI && "Type Transform failed?");5871    Function->setType(NewSI->getType());5872    Function->setTypeSourceInfo(NewSI);5873 5874    ParmVarDecl *Parm = Function->getParamDecl(0);5875    TypeSourceInfo *NewParmSI = IR.TransformType(Parm->getTypeSourceInfo());5876    assert(NewParmSI && "Type transformation failed.");5877    Parm->setType(NewParmSI->getType());5878    Parm->setTypeSourceInfo(NewParmSI);5879  };5880 5881  if (PatternDecl->isDefaulted()) {5882    RebuildTypeSourceInfoForDefaultSpecialMembers();5883    SetDeclDefaulted(Function, PatternDecl->getLocation());5884  } else {5885    DeclContext *DC = Function->getLexicalDeclContext();5886    std::optional<ArrayRef<TemplateArgument>> Innermost;5887    if (auto *Primary = Function->getPrimaryTemplate();5888        Primary &&5889        !isGenericLambdaCallOperatorOrStaticInvokerSpecialization(Function) &&5890        Function->getTemplateSpecializationKind() !=5891            TSK_ExplicitSpecialization) {5892      auto It = llvm::find_if(Primary->redecls(),5893                              [](const RedeclarableTemplateDecl *RTD) {5894                                return cast<FunctionTemplateDecl>(RTD)5895                                    ->isCompatibleWithDefinition();5896                              });5897      assert(It != Primary->redecls().end() &&5898             "Should't get here without a definition");5899      if (FunctionDecl *Def = cast<FunctionTemplateDecl>(*It)5900                                  ->getTemplatedDecl()5901                                  ->getDefinition())5902        DC = Def->getLexicalDeclContext();5903      else5904        DC = (*It)->getLexicalDeclContext();5905      Innermost.emplace(Function->getTemplateSpecializationArgs()->asArray());5906    }5907    MultiLevelTemplateArgumentList TemplateArgs = getTemplateInstantiationArgs(5908        Function, DC, /*Final=*/false, Innermost, false, PatternDecl);5909 5910    // Substitute into the qualifier; we can get a substitution failure here5911    // through evil use of alias templates.5912    // FIXME: Is CurContext correct for this? Should we go to the (instantiation5913    // of the) lexical context of the pattern?5914    SubstQualifier(*this, PatternDecl, Function, TemplateArgs);5915 5916    ActOnStartOfFunctionDef(nullptr, Function);5917 5918    // Enter the scope of this instantiation. We don't use5919    // PushDeclContext because we don't have a scope.5920    Sema::ContextRAII savedContext(*this, Function);5921 5922    FPFeaturesStateRAII SavedFPFeatures(*this);5923    CurFPFeatures = FPOptions(getLangOpts());5924    FpPragmaStack.CurrentValue = FPOptionsOverride();5925 5926    if (addInstantiatedParametersToScope(Function, PatternDecl, Scope,5927                                         TemplateArgs))5928      return;5929 5930    StmtResult Body;5931    if (PatternDecl->hasSkippedBody()) {5932      ActOnSkippedFunctionBody(Function);5933      Body = nullptr;5934    } else {5935      if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Function)) {5936        // If this is a constructor, instantiate the member initializers.5937        InstantiateMemInitializers(Ctor, cast<CXXConstructorDecl>(PatternDecl),5938                                   TemplateArgs);5939 5940        // If this is an MS ABI dllexport default constructor, instantiate any5941        // default arguments.5942        if (Context.getTargetInfo().getCXXABI().isMicrosoft() &&5943            Ctor->isDefaultConstructor()) {5944          InstantiateDefaultCtorDefaultArgs(Ctor);5945        }5946      }5947 5948      // Instantiate the function body.5949      Body = SubstStmt(Pattern, TemplateArgs);5950 5951      if (Body.isInvalid())5952        Function->setInvalidDecl();5953    }5954    // FIXME: finishing the function body while in an expression evaluation5955    // context seems wrong. Investigate more.5956    ActOnFinishFunctionBody(Function, Body.get(), /*IsInstantiation=*/true);5957 5958    checkReferenceToTULocalFromOtherTU(Function, PointOfInstantiation);5959 5960    PerformDependentDiagnostics(PatternDecl, TemplateArgs);5961 5962    if (auto *Listener = getASTMutationListener())5963      Listener->FunctionDefinitionInstantiated(Function);5964 5965    savedContext.pop();5966  }5967 5968  // We never need to emit the code for a lambda in unevaluated context.5969  // We also can't mangle a lambda in the require clause of a function template5970  // during constraint checking as the MSI ABI would need to mangle the (not yet5971  // specialized) enclosing declaration5972  // FIXME: Should we try to skip this for non-lambda functions too?5973  bool ShouldSkipCG = [&] {5974    auto *RD = dyn_cast<CXXRecordDecl>(Function->getParent());5975    if (!RD || !RD->isLambda())5976      return false;5977 5978    return llvm::any_of(ExprEvalContexts, [](auto &Context) {5979      return Context.isUnevaluated() || Context.isImmediateFunctionContext();5980    });5981  }();5982  if (!ShouldSkipCG) {5983    DeclGroupRef DG(Function);5984    Consumer.HandleTopLevelDecl(DG);5985  }5986 5987  // This class may have local implicit instantiations that need to be5988  // instantiation within this scope.5989  LocalInstantiations.perform();5990  Scope.Exit();5991  GlobalInstantiations.perform();5992}5993 5994VarTemplateSpecializationDecl *Sema::BuildVarTemplateInstantiation(5995    VarTemplateDecl *VarTemplate, VarDecl *FromVar,5996    const TemplateArgumentList *PartialSpecArgs,5997    SmallVectorImpl<TemplateArgument> &Converted,5998    SourceLocation PointOfInstantiation, LateInstantiatedAttrVec *LateAttrs,5999    LocalInstantiationScope *StartingScope) {6000  if (FromVar->isInvalidDecl())6001    return nullptr;6002 6003  NonSFINAEContext _(*this);6004  InstantiatingTemplate Inst(*this, PointOfInstantiation, FromVar);6005  if (Inst.isInvalid())6006    return nullptr;6007 6008  // Instantiate the first declaration of the variable template: for a partial6009  // specialization of a static data member template, the first declaration may6010  // or may not be the declaration in the class; if it's in the class, we want6011  // to instantiate a member in the class (a declaration), and if it's outside,6012  // we want to instantiate a definition.6013  //6014  // If we're instantiating an explicitly-specialized member template or member6015  // partial specialization, don't do this. The member specialization completely6016  // replaces the original declaration in this case.6017  bool IsMemberSpec = false;6018  MultiLevelTemplateArgumentList MultiLevelList;6019  if (auto *PartialSpec =6020          dyn_cast<VarTemplatePartialSpecializationDecl>(FromVar)) {6021    assert(PartialSpecArgs);6022    IsMemberSpec = PartialSpec->isMemberSpecialization();6023    MultiLevelList.addOuterTemplateArguments(6024        PartialSpec, PartialSpecArgs->asArray(), /*Final=*/false);6025  } else {6026    assert(VarTemplate == FromVar->getDescribedVarTemplate());6027    IsMemberSpec = VarTemplate->isMemberSpecialization();6028    MultiLevelList.addOuterTemplateArguments(VarTemplate, Converted,6029                                             /*Final=*/false);6030  }6031  if (!IsMemberSpec)6032    FromVar = FromVar->getFirstDecl();6033 6034  TemplateDeclInstantiator Instantiator(*this, FromVar->getDeclContext(),6035                                        MultiLevelList);6036 6037  // TODO: Set LateAttrs and StartingScope ...6038 6039  return Instantiator.VisitVarTemplateSpecializationDecl(VarTemplate, FromVar,6040                                                         Converted);6041}6042 6043VarTemplateSpecializationDecl *Sema::CompleteVarTemplateSpecializationDecl(6044    VarTemplateSpecializationDecl *VarSpec, VarDecl *PatternDecl,6045    const MultiLevelTemplateArgumentList &TemplateArgs) {6046  assert(PatternDecl->isThisDeclarationADefinition() &&6047         "don't have a definition to instantiate from");6048 6049  // Do substitution on the type of the declaration6050  TypeSourceInfo *TSI =6051      SubstType(PatternDecl->getTypeSourceInfo(), TemplateArgs,6052                PatternDecl->getTypeSpecStartLoc(), PatternDecl->getDeclName());6053  if (!TSI)6054    return nullptr;6055 6056  // Update the type of this variable template specialization.6057  VarSpec->setType(TSI->getType());6058 6059  // Convert the declaration into a definition now.6060  VarSpec->setCompleteDefinition();6061 6062  // Instantiate the initializer.6063  InstantiateVariableInitializer(VarSpec, PatternDecl, TemplateArgs);6064 6065  if (getLangOpts().OpenCL)6066    deduceOpenCLAddressSpace(VarSpec);6067 6068  return VarSpec;6069}6070 6071void Sema::BuildVariableInstantiation(6072    VarDecl *NewVar, VarDecl *OldVar,6073    const MultiLevelTemplateArgumentList &TemplateArgs,6074    LateInstantiatedAttrVec *LateAttrs, DeclContext *Owner,6075    LocalInstantiationScope *StartingScope,6076    bool InstantiatingVarTemplate,6077    VarTemplateSpecializationDecl *PrevDeclForVarTemplateSpecialization) {6078  // Instantiating a partial specialization to produce a partial6079  // specialization.6080  bool InstantiatingVarTemplatePartialSpec =6081      isa<VarTemplatePartialSpecializationDecl>(OldVar) &&6082      isa<VarTemplatePartialSpecializationDecl>(NewVar);6083  // Instantiating from a variable template (or partial specialization) to6084  // produce a variable template specialization.6085  bool InstantiatingSpecFromTemplate =6086      isa<VarTemplateSpecializationDecl>(NewVar) &&6087      (OldVar->getDescribedVarTemplate() ||6088       isa<VarTemplatePartialSpecializationDecl>(OldVar));6089 6090  // If we are instantiating a local extern declaration, the6091  // instantiation belongs lexically to the containing function.6092  // If we are instantiating a static data member defined6093  // out-of-line, the instantiation will have the same lexical6094  // context (which will be a namespace scope) as the template.6095  if (OldVar->isLocalExternDecl()) {6096    NewVar->setLocalExternDecl();6097    NewVar->setLexicalDeclContext(Owner);6098  } else if (OldVar->isOutOfLine())6099    NewVar->setLexicalDeclContext(OldVar->getLexicalDeclContext());6100  NewVar->setTSCSpec(OldVar->getTSCSpec());6101  NewVar->setInitStyle(OldVar->getInitStyle());6102  NewVar->setCXXForRangeDecl(OldVar->isCXXForRangeDecl());6103  NewVar->setObjCForDecl(OldVar->isObjCForDecl());6104  NewVar->setConstexpr(OldVar->isConstexpr());6105  NewVar->setInitCapture(OldVar->isInitCapture());6106  NewVar->setPreviousDeclInSameBlockScope(6107      OldVar->isPreviousDeclInSameBlockScope());6108  NewVar->setAccess(OldVar->getAccess());6109 6110  if (!OldVar->isStaticDataMember()) {6111    if (OldVar->isUsed(false))6112      NewVar->setIsUsed();6113    NewVar->setReferenced(OldVar->isReferenced());6114  }6115 6116  InstantiateAttrs(TemplateArgs, OldVar, NewVar, LateAttrs, StartingScope);6117 6118  LookupResult Previous(6119      *this, NewVar->getDeclName(), NewVar->getLocation(),6120      NewVar->isLocalExternDecl() ? Sema::LookupRedeclarationWithLinkage6121                                  : Sema::LookupOrdinaryName,6122      NewVar->isLocalExternDecl() ? RedeclarationKind::ForExternalRedeclaration6123                                  : forRedeclarationInCurContext());6124 6125  if (NewVar->isLocalExternDecl() && OldVar->getPreviousDecl() &&6126      (!OldVar->getPreviousDecl()->getDeclContext()->isDependentContext() ||6127       OldVar->getPreviousDecl()->getDeclContext()==OldVar->getDeclContext())) {6128    // We have a previous declaration. Use that one, so we merge with the6129    // right type.6130    if (NamedDecl *NewPrev = FindInstantiatedDecl(6131            NewVar->getLocation(), OldVar->getPreviousDecl(), TemplateArgs))6132      Previous.addDecl(NewPrev);6133  } else if (!isa<VarTemplateSpecializationDecl>(NewVar) &&6134             OldVar->hasLinkage()) {6135    LookupQualifiedName(Previous, NewVar->getDeclContext(), false);6136  } else if (PrevDeclForVarTemplateSpecialization) {6137    Previous.addDecl(PrevDeclForVarTemplateSpecialization);6138  }6139  CheckVariableDeclaration(NewVar, Previous);6140 6141  if (!InstantiatingVarTemplate) {6142    NewVar->getLexicalDeclContext()->addHiddenDecl(NewVar);6143    if (!NewVar->isLocalExternDecl() || !NewVar->getPreviousDecl())6144      NewVar->getDeclContext()->makeDeclVisibleInContext(NewVar);6145  }6146 6147  if (!OldVar->isOutOfLine()) {6148    if (NewVar->getDeclContext()->isFunctionOrMethod())6149      CurrentInstantiationScope->InstantiatedLocal(OldVar, NewVar);6150  }6151 6152  // Link instantiations of static data members back to the template from6153  // which they were instantiated.6154  //6155  // Don't do this when instantiating a template (we link the template itself6156  // back in that case) nor when instantiating a static data member template6157  // (that's not a member specialization).6158  if (NewVar->isStaticDataMember() && !InstantiatingVarTemplate &&6159      !InstantiatingSpecFromTemplate)6160    NewVar->setInstantiationOfStaticDataMember(OldVar,6161                                               TSK_ImplicitInstantiation);6162 6163  // If the pattern is an (in-class) explicit specialization, then the result6164  // is also an explicit specialization.6165  if (VarTemplateSpecializationDecl *OldVTSD =6166          dyn_cast<VarTemplateSpecializationDecl>(OldVar)) {6167    if (OldVTSD->getSpecializationKind() == TSK_ExplicitSpecialization &&6168        !isa<VarTemplatePartialSpecializationDecl>(OldVTSD))6169      cast<VarTemplateSpecializationDecl>(NewVar)->setSpecializationKind(6170          TSK_ExplicitSpecialization);6171  }6172 6173  // Forward the mangling number from the template to the instantiated decl.6174  Context.setManglingNumber(NewVar, Context.getManglingNumber(OldVar));6175  Context.setStaticLocalNumber(NewVar, Context.getStaticLocalNumber(OldVar));6176 6177  // Figure out whether to eagerly instantiate the initializer.6178  if (InstantiatingVarTemplate || InstantiatingVarTemplatePartialSpec) {6179    // We're producing a template. Don't instantiate the initializer yet.6180  } else if (NewVar->getType()->isUndeducedType()) {6181    // We need the type to complete the declaration of the variable.6182    InstantiateVariableInitializer(NewVar, OldVar, TemplateArgs);6183  } else if (InstantiatingSpecFromTemplate ||6184             (OldVar->isInline() && OldVar->isThisDeclarationADefinition() &&6185              !NewVar->isThisDeclarationADefinition())) {6186    // Delay instantiation of the initializer for variable template6187    // specializations or inline static data members until a definition of the6188    // variable is needed.6189  } else {6190    InstantiateVariableInitializer(NewVar, OldVar, TemplateArgs);6191  }6192 6193  // Diagnose unused local variables with dependent types, where the diagnostic6194  // will have been deferred.6195  if (!NewVar->isInvalidDecl() &&6196      NewVar->getDeclContext()->isFunctionOrMethod() &&6197      OldVar->getType()->isDependentType())6198    DiagnoseUnusedDecl(NewVar);6199}6200 6201void Sema::InstantiateVariableInitializer(6202    VarDecl *Var, VarDecl *OldVar,6203    const MultiLevelTemplateArgumentList &TemplateArgs) {6204  if (ASTMutationListener *L = getASTContext().getASTMutationListener())6205    L->VariableDefinitionInstantiated(Var);6206 6207  // We propagate the 'inline' flag with the initializer, because it6208  // would otherwise imply that the variable is a definition for a6209  // non-static data member.6210  if (OldVar->isInlineSpecified())6211    Var->setInlineSpecified();6212  else if (OldVar->isInline())6213    Var->setImplicitlyInline();6214 6215  ContextRAII SwitchContext(*this, Var->getDeclContext());6216 6217  EnterExpressionEvaluationContext Evaluated(6218      *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated, Var,6219      ExpressionEvaluationContextRecord::EK_VariableInit);6220  currentEvaluationContext().InLifetimeExtendingContext =6221      parentEvaluationContext().InLifetimeExtendingContext;6222  currentEvaluationContext().RebuildDefaultArgOrDefaultInit =6223      parentEvaluationContext().RebuildDefaultArgOrDefaultInit;6224 6225  // Set DeclForInitializer for this variable so DiagIfReachable can properly6226  // suppress runtime diagnostics for constexpr/static member variables6227  currentEvaluationContext().DeclForInitializer = Var;6228 6229  if (OldVar->getInit()) {6230    // Instantiate the initializer.6231    ExprResult Init =6232        SubstInitializer(OldVar->getInit(), TemplateArgs,6233                         OldVar->getInitStyle() == VarDecl::CallInit);6234 6235    if (!Init.isInvalid()) {6236      Expr *InitExpr = Init.get();6237 6238      if (Var->hasAttr<DLLImportAttr>() &&6239          (!InitExpr ||6240           !InitExpr->isConstantInitializer(getASTContext(), false))) {6241        // Do not dynamically initialize dllimport variables.6242      } else if (InitExpr) {6243        bool DirectInit = OldVar->isDirectInit();6244        AddInitializerToDecl(Var, InitExpr, DirectInit);6245      } else6246        ActOnUninitializedDecl(Var);6247    } else {6248      // FIXME: Not too happy about invalidating the declaration6249      // because of a bogus initializer.6250      Var->setInvalidDecl();6251    }6252  } else {6253    // `inline` variables are a definition and declaration all in one; we won't6254    // pick up an initializer from anywhere else.6255    if (Var->isStaticDataMember() && !Var->isInline()) {6256      if (!Var->isOutOfLine())6257        return;6258 6259      // If the declaration inside the class had an initializer, don't add6260      // another one to the out-of-line definition.6261      if (OldVar->getFirstDecl()->hasInit())6262        return;6263    }6264 6265    // We'll add an initializer to a for-range declaration later.6266    if (Var->isCXXForRangeDecl() || Var->isObjCForDecl())6267      return;6268 6269    ActOnUninitializedDecl(Var);6270  }6271 6272  if (getLangOpts().CUDA)6273    CUDA().checkAllowedInitializer(Var);6274}6275 6276void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,6277                                         VarDecl *Var, bool Recursive,6278                                      bool DefinitionRequired, bool AtEndOfTU) {6279  if (Var->isInvalidDecl())6280    return;6281 6282  // Never instantiate an explicitly-specialized entity.6283  TemplateSpecializationKind TSK =6284      Var->getTemplateSpecializationKindForInstantiation();6285  if (TSK == TSK_ExplicitSpecialization)6286    return;6287 6288  RecursiveInstGuard AlreadyInstantiating(*this, Var,6289                                          RecursiveInstGuard::Kind::Template);6290  if (AlreadyInstantiating)6291    return;6292 6293  // Find the pattern and the arguments to substitute into it.6294  VarDecl *PatternDecl = Var->getTemplateInstantiationPattern();6295  assert(PatternDecl && "no pattern for templated variable");6296  MultiLevelTemplateArgumentList TemplateArgs =6297      getTemplateInstantiationArgs(Var);6298 6299  VarTemplateSpecializationDecl *VarSpec =6300      dyn_cast<VarTemplateSpecializationDecl>(Var);6301  if (VarSpec) {6302    // If this is a static data member template, there might be an6303    // uninstantiated initializer on the declaration. If so, instantiate6304    // it now.6305    //6306    // FIXME: This largely duplicates what we would do below. The difference6307    // is that along this path we may instantiate an initializer from an6308    // in-class declaration of the template and instantiate the definition6309    // from a separate out-of-class definition.6310    if (PatternDecl->isStaticDataMember() &&6311        (PatternDecl = PatternDecl->getFirstDecl())->hasInit() &&6312        !Var->hasInit()) {6313      // FIXME: Factor out the duplicated instantiation context setup/tear down6314      // code here.6315      NonSFINAEContext _(*this);6316      InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);6317      if (Inst.isInvalid())6318        return;6319      PrettyDeclStackTraceEntry CrashInfo(Context, Var, SourceLocation(),6320                                          "instantiating variable initializer");6321 6322      // The instantiation is visible here, even if it was first declared in an6323      // unimported module.6324      Var->setVisibleDespiteOwningModule();6325 6326      // If we're performing recursive template instantiation, create our own6327      // queue of pending implicit instantiations that we will instantiate6328      // later, while we're still within our own instantiation context.6329      GlobalEagerInstantiationScope GlobalInstantiations(6330          *this,6331          /*Enabled=*/Recursive, /*AtEndOfTU=*/AtEndOfTU);6332      LocalInstantiationScope Local(*this);6333      LocalEagerInstantiationScope LocalInstantiations(*this,6334                                                       /*AtEndOfTU=*/AtEndOfTU);6335 6336      // Enter the scope of this instantiation. We don't use6337      // PushDeclContext because we don't have a scope.6338      ContextRAII PreviousContext(*this, Var->getDeclContext());6339      InstantiateVariableInitializer(Var, PatternDecl, TemplateArgs);6340      PreviousContext.pop();6341 6342      // This variable may have local implicit instantiations that need to be6343      // instantiated within this scope.6344      LocalInstantiations.perform();6345      Local.Exit();6346      GlobalInstantiations.perform();6347    }6348  } else {6349    assert(Var->isStaticDataMember() && PatternDecl->isStaticDataMember() &&6350           "not a static data member?");6351  }6352 6353  VarDecl *Def = PatternDecl->getDefinition(getASTContext());6354 6355  // If we don't have a definition of the variable template, we won't perform6356  // any instantiation. Rather, we rely on the user to instantiate this6357  // definition (or provide a specialization for it) in another translation6358  // unit.6359  if (!Def && !DefinitionRequired) {6360    if (TSK == TSK_ExplicitInstantiationDefinition) {6361      PendingInstantiations.emplace_back(Var, PointOfInstantiation);6362    } else if (TSK == TSK_ImplicitInstantiation) {6363      // Warn about missing definition at the end of translation unit.6364      if (AtEndOfTU && !getDiagnostics().hasErrorOccurred() &&6365          !getSourceManager().isInSystemHeader(PatternDecl->getBeginLoc())) {6366        Diag(PointOfInstantiation, diag::warn_var_template_missing)6367          << Var;6368        Diag(PatternDecl->getLocation(), diag::note_forward_template_decl);6369        if (getLangOpts().CPlusPlus11)6370          Diag(PointOfInstantiation, diag::note_inst_declaration_hint) << Var;6371      }6372      return;6373    }6374  }6375 6376  // FIXME: We need to track the instantiation stack in order to know which6377  // definitions should be visible within this instantiation.6378  // FIXME: Produce diagnostics when Var->getInstantiatedFromStaticDataMember().6379  if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Var,6380                                     /*InstantiatedFromMember*/false,6381                                     PatternDecl, Def, TSK,6382                                     /*Complain*/DefinitionRequired))6383    return;6384 6385  // C++11 [temp.explicit]p10:6386  //   Except for inline functions, const variables of literal types, variables6387  //   of reference types, [...] explicit instantiation declarations6388  //   have the effect of suppressing the implicit instantiation of the entity6389  //   to which they refer.6390  //6391  // FIXME: That's not exactly the same as "might be usable in constant6392  // expressions", which only allows constexpr variables and const integral6393  // types, not arbitrary const literal types.6394  if (TSK == TSK_ExplicitInstantiationDeclaration &&6395      !Var->mightBeUsableInConstantExpressions(getASTContext()))6396    return;6397 6398  // Make sure to pass the instantiated variable to the consumer at the end.6399  struct PassToConsumerRAII {6400    ASTConsumer &Consumer;6401    VarDecl *Var;6402 6403    PassToConsumerRAII(ASTConsumer &Consumer, VarDecl *Var)6404      : Consumer(Consumer), Var(Var) { }6405 6406    ~PassToConsumerRAII() {6407      Consumer.HandleCXXStaticMemberVarInstantiation(Var);6408    }6409  } PassToConsumerRAII(Consumer, Var);6410 6411  // If we already have a definition, we're done.6412  if (VarDecl *Def = Var->getDefinition()) {6413    // We may be explicitly instantiating something we've already implicitly6414    // instantiated.6415    Def->setTemplateSpecializationKind(Var->getTemplateSpecializationKind(),6416                                       PointOfInstantiation);6417    return;6418  }6419 6420  NonSFINAEContext _(*this);6421  InstantiatingTemplate Inst(*this, PointOfInstantiation, Var);6422  if (Inst.isInvalid())6423    return;6424  PrettyDeclStackTraceEntry CrashInfo(Context, Var, SourceLocation(),6425                                      "instantiating variable definition");6426 6427  // If we're performing recursive template instantiation, create our own6428  // queue of pending implicit instantiations that we will instantiate later,6429  // while we're still within our own instantiation context.6430  GlobalEagerInstantiationScope GlobalInstantiations(*this,6431                                                     /*Enabled=*/Recursive,6432                                                     /*AtEndOfTU=*/AtEndOfTU);6433 6434  // Enter the scope of this instantiation. We don't use6435  // PushDeclContext because we don't have a scope.6436  ContextRAII PreviousContext(*this, Var->getDeclContext());6437  LocalInstantiationScope Local(*this);6438 6439  LocalEagerInstantiationScope LocalInstantiations(*this,6440                                                   /*AtEndOfTU=*/AtEndOfTU);6441 6442  VarDecl *OldVar = Var;6443  if (Def->isStaticDataMember() && !Def->isOutOfLine()) {6444    // We're instantiating an inline static data member whose definition was6445    // provided inside the class.6446    InstantiateVariableInitializer(Var, Def, TemplateArgs);6447  } else if (!VarSpec) {6448    Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),6449                                          TemplateArgs));6450  } else if (Var->isStaticDataMember() &&6451             Var->getLexicalDeclContext()->isRecord()) {6452    // We need to instantiate the definition of a static data member template,6453    // and all we have is the in-class declaration of it. Instantiate a separate6454    // declaration of the definition.6455    TemplateDeclInstantiator Instantiator(*this, Var->getDeclContext(),6456                                          TemplateArgs);6457 6458    TemplateArgumentListInfo TemplateArgInfo;6459    if (const ASTTemplateArgumentListInfo *ArgInfo =6460            VarSpec->getTemplateArgsAsWritten()) {6461      TemplateArgInfo.setLAngleLoc(ArgInfo->getLAngleLoc());6462      TemplateArgInfo.setRAngleLoc(ArgInfo->getRAngleLoc());6463      for (const TemplateArgumentLoc &Arg : ArgInfo->arguments())6464        TemplateArgInfo.addArgument(Arg);6465    }6466 6467    VarTemplateSpecializationDecl *VTSD =6468        Instantiator.VisitVarTemplateSpecializationDecl(6469            VarSpec->getSpecializedTemplate(), Def,6470            VarSpec->getTemplateArgs().asArray(), VarSpec);6471    Var = VTSD;6472 6473    if (Var) {6474      VTSD->setTemplateArgsAsWritten(TemplateArgInfo);6475 6476      llvm::PointerUnion<VarTemplateDecl *,6477                         VarTemplatePartialSpecializationDecl *> PatternPtr =6478          VarSpec->getSpecializedTemplateOrPartial();6479      if (VarTemplatePartialSpecializationDecl *Partial =6480          PatternPtr.dyn_cast<VarTemplatePartialSpecializationDecl *>())6481        cast<VarTemplateSpecializationDecl>(Var)->setInstantiationOf(6482            Partial, &VarSpec->getTemplateInstantiationArgs());6483 6484      // Attach the initializer.6485      InstantiateVariableInitializer(Var, Def, TemplateArgs);6486    }6487  } else6488    // Complete the existing variable's definition with an appropriately6489    // substituted type and initializer.6490    Var = CompleteVarTemplateSpecializationDecl(VarSpec, Def, TemplateArgs);6491 6492  PreviousContext.pop();6493 6494  if (Var) {6495    PassToConsumerRAII.Var = Var;6496    Var->setTemplateSpecializationKind(OldVar->getTemplateSpecializationKind(),6497                                       OldVar->getPointOfInstantiation());6498    // Emit any deferred warnings for the variable's initializer6499    AnalysisWarnings.issueWarningsForRegisteredVarDecl(Var);6500  }6501 6502  // This variable may have local implicit instantiations that need to be6503  // instantiated within this scope.6504  LocalInstantiations.perform();6505  Local.Exit();6506  GlobalInstantiations.perform();6507}6508 6509void6510Sema::InstantiateMemInitializers(CXXConstructorDecl *New,6511                                 const CXXConstructorDecl *Tmpl,6512                           const MultiLevelTemplateArgumentList &TemplateArgs) {6513 6514  SmallVector<CXXCtorInitializer*, 4> NewInits;6515  bool AnyErrors = Tmpl->isInvalidDecl();6516 6517  // Instantiate all the initializers.6518  for (const auto *Init : Tmpl->inits()) {6519    // Only instantiate written initializers, let Sema re-construct implicit6520    // ones.6521    if (!Init->isWritten())6522      continue;6523 6524    SourceLocation EllipsisLoc;6525 6526    if (Init->isPackExpansion()) {6527      // This is a pack expansion. We should expand it now.6528      TypeLoc BaseTL = Init->getTypeSourceInfo()->getTypeLoc();6529      SmallVector<UnexpandedParameterPack, 4> Unexpanded;6530      collectUnexpandedParameterPacks(BaseTL, Unexpanded);6531      collectUnexpandedParameterPacks(Init->getInit(), Unexpanded);6532      bool ShouldExpand = false;6533      bool RetainExpansion = false;6534      UnsignedOrNone NumExpansions = std::nullopt;6535      if (CheckParameterPacksForExpansion(6536              Init->getEllipsisLoc(), BaseTL.getSourceRange(), Unexpanded,6537              TemplateArgs, /*FailOnPackProducingTemplates=*/true, ShouldExpand,6538              RetainExpansion, NumExpansions)) {6539        AnyErrors = true;6540        New->setInvalidDecl();6541        continue;6542      }6543      assert(ShouldExpand && "Partial instantiation of base initializer?");6544 6545      // Loop over all of the arguments in the argument pack(s),6546      for (unsigned I = 0; I != *NumExpansions; ++I) {6547        Sema::ArgPackSubstIndexRAII SubstIndex(*this, I);6548 6549        // Instantiate the initializer.6550        ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,6551                                               /*CXXDirectInit=*/true);6552        if (TempInit.isInvalid()) {6553          AnyErrors = true;6554          break;6555        }6556 6557        // Instantiate the base type.6558        TypeSourceInfo *BaseTInfo = SubstType(Init->getTypeSourceInfo(),6559                                              TemplateArgs,6560                                              Init->getSourceLocation(),6561                                              New->getDeclName());6562        if (!BaseTInfo) {6563          AnyErrors = true;6564          break;6565        }6566 6567        // Build the initializer.6568        MemInitResult NewInit = BuildBaseInitializer(BaseTInfo->getType(),6569                                                     BaseTInfo, TempInit.get(),6570                                                     New->getParent(),6571                                                     SourceLocation());6572        if (NewInit.isInvalid()) {6573          AnyErrors = true;6574          break;6575        }6576 6577        NewInits.push_back(NewInit.get());6578      }6579 6580      continue;6581    }6582 6583    // Instantiate the initializer.6584    ExprResult TempInit = SubstInitializer(Init->getInit(), TemplateArgs,6585                                           /*CXXDirectInit=*/true);6586    if (TempInit.isInvalid()) {6587      AnyErrors = true;6588      continue;6589    }6590 6591    MemInitResult NewInit;6592    if (Init->isDelegatingInitializer() || Init->isBaseInitializer()) {6593      TypeSourceInfo *TInfo = SubstType(Init->getTypeSourceInfo(),6594                                        TemplateArgs,6595                                        Init->getSourceLocation(),6596                                        New->getDeclName());6597      if (!TInfo) {6598        AnyErrors = true;6599        New->setInvalidDecl();6600        continue;6601      }6602 6603      if (Init->isBaseInitializer())6604        NewInit = BuildBaseInitializer(TInfo->getType(), TInfo, TempInit.get(),6605                                       New->getParent(), EllipsisLoc);6606      else6607        NewInit = BuildDelegatingInitializer(TInfo, TempInit.get(),6608                                  cast<CXXRecordDecl>(CurContext->getParent()));6609    } else if (Init->isMemberInitializer()) {6610      FieldDecl *Member = cast_or_null<FieldDecl>(FindInstantiatedDecl(6611                                                     Init->getMemberLocation(),6612                                                     Init->getMember(),6613                                                     TemplateArgs));6614      if (!Member) {6615        AnyErrors = true;6616        New->setInvalidDecl();6617        continue;6618      }6619 6620      NewInit = BuildMemberInitializer(Member, TempInit.get(),6621                                       Init->getSourceLocation());6622    } else if (Init->isIndirectMemberInitializer()) {6623      IndirectFieldDecl *IndirectMember =6624         cast_or_null<IndirectFieldDecl>(FindInstantiatedDecl(6625                                 Init->getMemberLocation(),6626                                 Init->getIndirectMember(), TemplateArgs));6627 6628      if (!IndirectMember) {6629        AnyErrors = true;6630        New->setInvalidDecl();6631        continue;6632      }6633 6634      NewInit = BuildMemberInitializer(IndirectMember, TempInit.get(),6635                                       Init->getSourceLocation());6636    }6637 6638    if (NewInit.isInvalid()) {6639      AnyErrors = true;6640      New->setInvalidDecl();6641    } else {6642      NewInits.push_back(NewInit.get());6643    }6644  }6645 6646  // Assign all the initializers to the new constructor.6647  ActOnMemInitializers(New,6648                       /*FIXME: ColonLoc */6649                       SourceLocation(),6650                       NewInits,6651                       AnyErrors);6652}6653 6654// TODO: this could be templated if the various decl types used the6655// same method name.6656static bool isInstantiationOf(ClassTemplateDecl *Pattern,6657                              ClassTemplateDecl *Instance) {6658  Pattern = Pattern->getCanonicalDecl();6659 6660  do {6661    Instance = Instance->getCanonicalDecl();6662    if (Pattern == Instance) return true;6663    Instance = Instance->getInstantiatedFromMemberTemplate();6664  } while (Instance);6665 6666  return false;6667}6668 6669static bool isInstantiationOf(FunctionTemplateDecl *Pattern,6670                              FunctionTemplateDecl *Instance) {6671  Pattern = Pattern->getCanonicalDecl();6672 6673  do {6674    Instance = Instance->getCanonicalDecl();6675    if (Pattern == Instance) return true;6676    Instance = Instance->getInstantiatedFromMemberTemplate();6677  } while (Instance);6678 6679  return false;6680}6681 6682static bool6683isInstantiationOf(ClassTemplatePartialSpecializationDecl *Pattern,6684                  ClassTemplatePartialSpecializationDecl *Instance) {6685  Pattern6686    = cast<ClassTemplatePartialSpecializationDecl>(Pattern->getCanonicalDecl());6687  do {6688    Instance = cast<ClassTemplatePartialSpecializationDecl>(6689                                                Instance->getCanonicalDecl());6690    if (Pattern == Instance)6691      return true;6692    Instance = Instance->getInstantiatedFromMember();6693  } while (Instance);6694 6695  return false;6696}6697 6698static bool isInstantiationOf(CXXRecordDecl *Pattern,6699                              CXXRecordDecl *Instance) {6700  Pattern = Pattern->getCanonicalDecl();6701 6702  do {6703    Instance = Instance->getCanonicalDecl();6704    if (Pattern == Instance) return true;6705    Instance = Instance->getInstantiatedFromMemberClass();6706  } while (Instance);6707 6708  return false;6709}6710 6711static bool isInstantiationOf(FunctionDecl *Pattern,6712                              FunctionDecl *Instance) {6713  Pattern = Pattern->getCanonicalDecl();6714 6715  do {6716    Instance = Instance->getCanonicalDecl();6717    if (Pattern == Instance) return true;6718    Instance = Instance->getInstantiatedFromMemberFunction();6719  } while (Instance);6720 6721  return false;6722}6723 6724static bool isInstantiationOf(EnumDecl *Pattern,6725                              EnumDecl *Instance) {6726  Pattern = Pattern->getCanonicalDecl();6727 6728  do {6729    Instance = Instance->getCanonicalDecl();6730    if (Pattern == Instance) return true;6731    Instance = Instance->getInstantiatedFromMemberEnum();6732  } while (Instance);6733 6734  return false;6735}6736 6737static bool isInstantiationOf(UsingShadowDecl *Pattern,6738                              UsingShadowDecl *Instance,6739                              ASTContext &C) {6740  return declaresSameEntity(C.getInstantiatedFromUsingShadowDecl(Instance),6741                            Pattern);6742}6743 6744static bool isInstantiationOf(UsingDecl *Pattern, UsingDecl *Instance,6745                              ASTContext &C) {6746  return declaresSameEntity(C.getInstantiatedFromUsingDecl(Instance), Pattern);6747}6748 6749template<typename T>6750static bool isInstantiationOfUnresolvedUsingDecl(T *Pattern, Decl *Other,6751                                                 ASTContext &Ctx) {6752  // An unresolved using declaration can instantiate to an unresolved using6753  // declaration, or to a using declaration or a using declaration pack.6754  //6755  // Multiple declarations can claim to be instantiated from an unresolved6756  // using declaration if it's a pack expansion. We want the UsingPackDecl6757  // in that case, not the individual UsingDecls within the pack.6758  bool OtherIsPackExpansion;6759  NamedDecl *OtherFrom;6760  if (auto *OtherUUD = dyn_cast<T>(Other)) {6761    OtherIsPackExpansion = OtherUUD->isPackExpansion();6762    OtherFrom = Ctx.getInstantiatedFromUsingDecl(OtherUUD);6763  } else if (auto *OtherUPD = dyn_cast<UsingPackDecl>(Other)) {6764    OtherIsPackExpansion = true;6765    OtherFrom = OtherUPD->getInstantiatedFromUsingDecl();6766  } else if (auto *OtherUD = dyn_cast<UsingDecl>(Other)) {6767    OtherIsPackExpansion = false;6768    OtherFrom = Ctx.getInstantiatedFromUsingDecl(OtherUD);6769  } else {6770    return false;6771  }6772  return Pattern->isPackExpansion() == OtherIsPackExpansion &&6773         declaresSameEntity(OtherFrom, Pattern);6774}6775 6776static bool isInstantiationOfStaticDataMember(VarDecl *Pattern,6777                                              VarDecl *Instance) {6778  assert(Instance->isStaticDataMember());6779 6780  Pattern = Pattern->getCanonicalDecl();6781 6782  do {6783    Instance = Instance->getCanonicalDecl();6784    if (Pattern == Instance) return true;6785    Instance = Instance->getInstantiatedFromStaticDataMember();6786  } while (Instance);6787 6788  return false;6789}6790 6791// Other is the prospective instantiation6792// D is the prospective pattern6793static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {6794  if (auto *UUD = dyn_cast<UnresolvedUsingTypenameDecl>(D))6795    return isInstantiationOfUnresolvedUsingDecl(UUD, Other, Ctx);6796 6797  if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(D))6798    return isInstantiationOfUnresolvedUsingDecl(UUD, Other, Ctx);6799 6800  if (D->getKind() != Other->getKind())6801    return false;6802 6803  if (auto *Record = dyn_cast<CXXRecordDecl>(Other))6804    return isInstantiationOf(cast<CXXRecordDecl>(D), Record);6805 6806  if (auto *Function = dyn_cast<FunctionDecl>(Other))6807    return isInstantiationOf(cast<FunctionDecl>(D), Function);6808 6809  if (auto *Enum = dyn_cast<EnumDecl>(Other))6810    return isInstantiationOf(cast<EnumDecl>(D), Enum);6811 6812  if (auto *Var = dyn_cast<VarDecl>(Other))6813    if (Var->isStaticDataMember())6814      return isInstantiationOfStaticDataMember(cast<VarDecl>(D), Var);6815 6816  if (auto *Temp = dyn_cast<ClassTemplateDecl>(Other))6817    return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);6818 6819  if (auto *Temp = dyn_cast<FunctionTemplateDecl>(Other))6820    return isInstantiationOf(cast<FunctionTemplateDecl>(D), Temp);6821 6822  if (auto *PartialSpec =6823          dyn_cast<ClassTemplatePartialSpecializationDecl>(Other))6824    return isInstantiationOf(cast<ClassTemplatePartialSpecializationDecl>(D),6825                             PartialSpec);6826 6827  if (auto *Field = dyn_cast<FieldDecl>(Other)) {6828    if (!Field->getDeclName()) {6829      // This is an unnamed field.6830      return declaresSameEntity(Ctx.getInstantiatedFromUnnamedFieldDecl(Field),6831                                cast<FieldDecl>(D));6832    }6833  }6834 6835  if (auto *Using = dyn_cast<UsingDecl>(Other))6836    return isInstantiationOf(cast<UsingDecl>(D), Using, Ctx);6837 6838  if (auto *Shadow = dyn_cast<UsingShadowDecl>(Other))6839    return isInstantiationOf(cast<UsingShadowDecl>(D), Shadow, Ctx);6840 6841  return D->getDeclName() &&6842         D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();6843}6844 6845template<typename ForwardIterator>6846static NamedDecl *findInstantiationOf(ASTContext &Ctx,6847                                      NamedDecl *D,6848                                      ForwardIterator first,6849                                      ForwardIterator last) {6850  for (; first != last; ++first)6851    if (isInstantiationOf(Ctx, D, *first))6852      return cast<NamedDecl>(*first);6853 6854  return nullptr;6855}6856 6857DeclContext *Sema::FindInstantiatedContext(SourceLocation Loc, DeclContext* DC,6858                          const MultiLevelTemplateArgumentList &TemplateArgs) {6859  if (NamedDecl *D = dyn_cast<NamedDecl>(DC)) {6860    Decl* ID = FindInstantiatedDecl(Loc, D, TemplateArgs, true);6861    return cast_or_null<DeclContext>(ID);6862  } else return DC;6863}6864 6865/// Determine whether the given context is dependent on template parameters at6866/// level \p Level or below.6867///6868/// Sometimes we only substitute an inner set of template arguments and leave6869/// the outer templates alone. In such cases, contexts dependent only on the6870/// outer levels are not effectively dependent.6871static bool isDependentContextAtLevel(DeclContext *DC, unsigned Level) {6872  if (!DC->isDependentContext())6873    return false;6874  if (!Level)6875    return true;6876  return cast<Decl>(DC)->getTemplateDepth() > Level;6877}6878 6879NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,6880                          const MultiLevelTemplateArgumentList &TemplateArgs,6881                          bool FindingInstantiatedContext) {6882  DeclContext *ParentDC = D->getDeclContext();6883  // Determine whether our parent context depends on any of the template6884  // arguments we're currently substituting.6885  bool ParentDependsOnArgs = isDependentContextAtLevel(6886      ParentDC, TemplateArgs.getNumRetainedOuterLevels());6887  // FIXME: Parameters of pointer to functions (y below) that are themselves6888  // parameters (p below) can have their ParentDC set to the translation-unit6889  // - thus we can not consistently check if the ParentDC of such a parameter6890  // is Dependent or/and a FunctionOrMethod.6891  // For e.g. this code, during Template argument deduction tries to6892  // find an instantiated decl for (T y) when the ParentDC for y is6893  // the translation unit.6894  //   e.g. template <class T> void Foo(auto (*p)(T y) -> decltype(y())) {}6895  //   float baz(float(*)()) { return 0.0; }6896  //   Foo(baz);6897  // The better fix here is perhaps to ensure that a ParmVarDecl, by the time6898  // it gets here, always has a FunctionOrMethod as its ParentDC??6899  // For now:6900  //  - as long as we have a ParmVarDecl whose parent is non-dependent and6901  //    whose type is not instantiation dependent, do nothing to the decl6902  //  - otherwise find its instantiated decl.6903  if (isa<ParmVarDecl>(D) && !ParentDependsOnArgs &&6904      !cast<ParmVarDecl>(D)->getType()->isInstantiationDependentType())6905    return D;6906  if (isa<ParmVarDecl>(D) || isa<NonTypeTemplateParmDecl>(D) ||6907      isa<TemplateTypeParmDecl>(D) || isa<TemplateTemplateParmDecl>(D) ||6908      (ParentDependsOnArgs && (ParentDC->isFunctionOrMethod() ||6909                               isa<OMPDeclareReductionDecl>(ParentDC) ||6910                               isa<OMPDeclareMapperDecl>(ParentDC))) ||6911      (isa<CXXRecordDecl>(D) && cast<CXXRecordDecl>(D)->isLambda() &&6912       cast<CXXRecordDecl>(D)->getTemplateDepth() >6913           TemplateArgs.getNumRetainedOuterLevels())) {6914    // D is a local of some kind. Look into the map of local6915    // declarations to their instantiations.6916    if (CurrentInstantiationScope) {6917      if (auto Found = CurrentInstantiationScope->findInstantiationOf(D)) {6918        if (Decl *FD = Found->dyn_cast<Decl *>()) {6919          if (auto *BD = dyn_cast<BindingDecl>(FD);6920              BD && BD->isParameterPack() && ArgPackSubstIndex) {6921            return BD->getBindingPackDecls()[*ArgPackSubstIndex];6922          }6923          return cast<NamedDecl>(FD);6924        }6925 6926        assert(ArgPackSubstIndex &&6927               "found declaration pack but not pack expanding");6928        typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;6929        return cast<NamedDecl>(6930            (*cast<DeclArgumentPack *>(*Found))[*ArgPackSubstIndex]);6931      }6932    }6933 6934    // If we're performing a partial substitution during template argument6935    // deduction, we may not have values for template parameters yet. They6936    // just map to themselves.6937    if (isa<NonTypeTemplateParmDecl>(D) || isa<TemplateTypeParmDecl>(D) ||6938        isa<TemplateTemplateParmDecl>(D))6939      return D;6940 6941    if (D->isInvalidDecl())6942      return nullptr;6943 6944    // Normally this function only searches for already instantiated declaration6945    // however we have to make an exclusion for local types used before6946    // definition as in the code:6947    //6948    //   template<typename T> void f1() {6949    //     void g1(struct x1);6950    //     struct x1 {};6951    //   }6952    //6953    // In this case instantiation of the type of 'g1' requires definition of6954    // 'x1', which is defined later. Error recovery may produce an enum used6955    // before definition. In these cases we need to instantiate relevant6956    // declarations here.6957    bool NeedInstantiate = false;6958    if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D))6959      NeedInstantiate = RD->isLocalClass();6960    else if (isa<TypedefNameDecl>(D) &&6961             isa<CXXDeductionGuideDecl>(D->getDeclContext()))6962      NeedInstantiate = true;6963    else6964      NeedInstantiate = isa<EnumDecl>(D);6965    if (NeedInstantiate) {6966      Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);6967      CurrentInstantiationScope->InstantiatedLocal(D, Inst);6968      return cast<TypeDecl>(Inst);6969    }6970 6971    // If we didn't find the decl, then we must have a label decl that hasn't6972    // been found yet.  Lazily instantiate it and return it now.6973    assert(isa<LabelDecl>(D));6974 6975    Decl *Inst = SubstDecl(D, CurContext, TemplateArgs);6976    assert(Inst && "Failed to instantiate label??");6977 6978    CurrentInstantiationScope->InstantiatedLocal(D, Inst);6979    return cast<LabelDecl>(Inst);6980  }6981 6982  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {6983    if (!Record->isDependentContext())6984      return D;6985 6986    // Determine whether this record is the "templated" declaration describing6987    // a class template or class template specialization.6988    ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate();6989    if (ClassTemplate)6990      ClassTemplate = ClassTemplate->getCanonicalDecl();6991    else if (ClassTemplateSpecializationDecl *Spec =6992                 dyn_cast<ClassTemplateSpecializationDecl>(Record))6993      ClassTemplate = Spec->getSpecializedTemplate()->getCanonicalDecl();6994 6995    // Walk the current context to find either the record or an instantiation of6996    // it.6997    DeclContext *DC = CurContext;6998    while (!DC->isFileContext()) {6999      // If we're performing substitution while we're inside the template7000      // definition, we'll find our own context. We're done.7001      if (DC->Equals(Record))7002        return Record;7003 7004      if (CXXRecordDecl *InstRecord = dyn_cast<CXXRecordDecl>(DC)) {7005        // Check whether we're in the process of instantiating a class template7006        // specialization of the template we're mapping.7007        if (ClassTemplateSpecializationDecl *InstSpec7008                      = dyn_cast<ClassTemplateSpecializationDecl>(InstRecord)){7009          ClassTemplateDecl *SpecTemplate = InstSpec->getSpecializedTemplate();7010          if (ClassTemplate && isInstantiationOf(ClassTemplate, SpecTemplate))7011            return InstRecord;7012        }7013 7014        // Check whether we're in the process of instantiating a member class.7015        if (isInstantiationOf(Record, InstRecord))7016          return InstRecord;7017      }7018 7019      // Move to the outer template scope.7020      if (FunctionDecl *FD = dyn_cast<FunctionDecl>(DC)) {7021        if (FD->getFriendObjectKind() &&7022            FD->getNonTransparentDeclContext()->isFileContext()) {7023          DC = FD->getLexicalDeclContext();7024          continue;7025        }7026        // An implicit deduction guide acts as if it's within the class template7027        // specialization described by its name and first N template params.7028        auto *Guide = dyn_cast<CXXDeductionGuideDecl>(FD);7029        if (Guide && Guide->isImplicit()) {7030          TemplateDecl *TD = Guide->getDeducedTemplate();7031          // Convert the arguments to an "as-written" list.7032          TemplateArgumentListInfo Args(Loc, Loc);7033          for (TemplateArgument Arg : TemplateArgs.getInnermost().take_front(7034                                        TD->getTemplateParameters()->size())) {7035            ArrayRef<TemplateArgument> Unpacked(Arg);7036            if (Arg.getKind() == TemplateArgument::Pack)7037              Unpacked = Arg.pack_elements();7038            for (TemplateArgument UnpackedArg : Unpacked)7039              Args.addArgument(7040                  getTrivialTemplateArgumentLoc(UnpackedArg, QualType(), Loc));7041          }7042          QualType T = CheckTemplateIdType(7043              ElaboratedTypeKeyword::None, TemplateName(TD), Loc, Args,7044              /*Scope=*/nullptr, /*ForNestedNameSpecifier=*/false);7045          // We may get a non-null type with errors, in which case7046          // `getAsCXXRecordDecl` will return `nullptr`. For instance, this7047          // happens when one of the template arguments is an invalid7048          // expression. We return early to avoid triggering the assertion7049          // about the `CodeSynthesisContext`.7050          if (T.isNull() || T->containsErrors())7051            return nullptr;7052          CXXRecordDecl *SubstRecord = T->getAsCXXRecordDecl();7053 7054          if (!SubstRecord) {7055            // T can be a dependent TemplateSpecializationType when performing a7056            // substitution for building a deduction guide or for template7057            // argument deduction in the process of rebuilding immediate7058            // expressions. (Because the default argument that involves a lambda7059            // is untransformed and thus could be dependent at this point.)7060            assert(SemaRef.RebuildingImmediateInvocation ||7061                   CodeSynthesisContexts.back().Kind ==7062                       CodeSynthesisContext::BuildingDeductionGuides);7063            // Return a nullptr as a sentinel value, we handle it properly in7064            // the TemplateInstantiator::TransformInjectedClassNameType7065            // override, which we transform it to a TemplateSpecializationType.7066            return nullptr;7067          }7068          // Check that this template-id names the primary template and not a7069          // partial or explicit specialization. (In the latter cases, it's7070          // meaningless to attempt to find an instantiation of D within the7071          // specialization.)7072          // FIXME: The standard doesn't say what should happen here.7073          if (FindingInstantiatedContext &&7074              usesPartialOrExplicitSpecialization(7075                  Loc, cast<ClassTemplateSpecializationDecl>(SubstRecord))) {7076            Diag(Loc, diag::err_specialization_not_primary_template)7077              << T << (SubstRecord->getTemplateSpecializationKind() ==7078                           TSK_ExplicitSpecialization);7079            return nullptr;7080          }7081          DC = SubstRecord;7082          continue;7083        }7084      }7085 7086      DC = DC->getParent();7087    }7088 7089    // Fall through to deal with other dependent record types (e.g.,7090    // anonymous unions in class templates).7091  }7092 7093  if (!ParentDependsOnArgs)7094    return D;7095 7096  ParentDC = FindInstantiatedContext(Loc, ParentDC, TemplateArgs);7097  if (!ParentDC)7098    return nullptr;7099 7100  if (ParentDC != D->getDeclContext()) {7101    // We performed some kind of instantiation in the parent context,7102    // so now we need to look into the instantiated parent context to7103    // find the instantiation of the declaration D.7104 7105    // If our context used to be dependent, we may need to instantiate7106    // it before performing lookup into that context.7107    bool IsBeingInstantiated = false;7108    if (auto *Spec = dyn_cast<CXXRecordDecl>(ParentDC)) {7109      if (!Spec->isDependentContext()) {7110        if (Spec->isEntityBeingDefined())7111          IsBeingInstantiated = true;7112        else if (RequireCompleteType(Loc, Context.getCanonicalTagType(Spec),7113                                     diag::err_incomplete_type))7114          return nullptr;7115 7116        ParentDC = Spec->getDefinitionOrSelf();7117      }7118    }7119 7120    NamedDecl *Result = nullptr;7121    // FIXME: If the name is a dependent name, this lookup won't necessarily7122    // find it. Does that ever matter?7123    if (auto Name = D->getDeclName()) {7124      DeclarationNameInfo NameInfo(Name, D->getLocation());7125      DeclarationNameInfo NewNameInfo =7126          SubstDeclarationNameInfo(NameInfo, TemplateArgs);7127      Name = NewNameInfo.getName();7128      if (!Name)7129        return nullptr;7130      DeclContext::lookup_result Found = ParentDC->lookup(Name);7131 7132      Result = findInstantiationOf(Context, D, Found.begin(), Found.end());7133    } else {7134      // Since we don't have a name for the entity we're looking for,7135      // our only option is to walk through all of the declarations to7136      // find that name. This will occur in a few cases:7137      //7138      //   - anonymous struct/union within a template7139      //   - unnamed class/struct/union/enum within a template7140      //7141      // FIXME: Find a better way to find these instantiations!7142      Result = findInstantiationOf(Context, D,7143                                   ParentDC->decls_begin(),7144                                   ParentDC->decls_end());7145    }7146 7147    if (!Result) {7148      if (isa<UsingShadowDecl>(D)) {7149        // UsingShadowDecls can instantiate to nothing because of using hiding.7150      } else if (hasUncompilableErrorOccurred()) {7151        // We've already complained about some ill-formed code, so most likely7152        // this declaration failed to instantiate. There's no point in7153        // complaining further, since this is normal in invalid code.7154        // FIXME: Use more fine-grained 'invalid' tracking for this.7155      } else if (IsBeingInstantiated) {7156        // The class in which this member exists is currently being7157        // instantiated, and we haven't gotten around to instantiating this7158        // member yet. This can happen when the code uses forward declarations7159        // of member classes, and introduces ordering dependencies via7160        // template instantiation.7161        Diag(Loc, diag::err_member_not_yet_instantiated)7162            << D->getDeclName()7163            << Context.getCanonicalTagType(cast<CXXRecordDecl>(ParentDC));7164        Diag(D->getLocation(), diag::note_non_instantiated_member_here);7165      } else if (EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {7166        // This enumeration constant was found when the template was defined,7167        // but can't be found in the instantiation. This can happen if an7168        // unscoped enumeration member is explicitly specialized.7169        EnumDecl *Enum = cast<EnumDecl>(ED->getLexicalDeclContext());7170        EnumDecl *Spec = cast<EnumDecl>(FindInstantiatedDecl(Loc, Enum,7171                                                             TemplateArgs));7172        assert(Spec->getTemplateSpecializationKind() ==7173                 TSK_ExplicitSpecialization);7174        Diag(Loc, diag::err_enumerator_does_not_exist)7175          << D->getDeclName()7176          << Context.getTypeDeclType(cast<TypeDecl>(Spec->getDeclContext()));7177        Diag(Spec->getLocation(), diag::note_enum_specialized_here)7178            << Context.getCanonicalTagType(Spec);7179      } else {7180        // We should have found something, but didn't.7181        llvm_unreachable("Unable to find instantiation of declaration!");7182      }7183    }7184 7185    D = Result;7186  }7187 7188  return D;7189}7190 7191void Sema::PerformPendingInstantiations(bool LocalOnly, bool AtEndOfTU) {7192  std::deque<PendingImplicitInstantiation> DelayedImplicitInstantiations;7193  while (!PendingLocalImplicitInstantiations.empty() ||7194         (!LocalOnly && !PendingInstantiations.empty())) {7195    PendingImplicitInstantiation Inst;7196 7197    bool LocalInstantiation = false;7198    if (PendingLocalImplicitInstantiations.empty()) {7199      Inst = PendingInstantiations.front();7200      PendingInstantiations.pop_front();7201    } else {7202      Inst = PendingLocalImplicitInstantiations.front();7203      PendingLocalImplicitInstantiations.pop_front();7204      LocalInstantiation = true;7205    }7206 7207    // Instantiate function definitions7208    if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Inst.first)) {7209      bool DefinitionRequired = Function->getTemplateSpecializationKind() ==7210                                TSK_ExplicitInstantiationDefinition;7211      if (Function->isMultiVersion()) {7212        getASTContext().forEachMultiversionedFunctionVersion(7213            Function,7214            [this, Inst, DefinitionRequired, AtEndOfTU](FunctionDecl *CurFD) {7215              InstantiateFunctionDefinition(/*FIXME:*/ Inst.second, CurFD, true,7216                                            DefinitionRequired, AtEndOfTU);7217              if (CurFD->isDefined())7218                CurFD->setInstantiationIsPending(false);7219            });7220      } else {7221        InstantiateFunctionDefinition(/*FIXME:*/ Inst.second, Function, true,7222                                      DefinitionRequired, AtEndOfTU);7223        if (Function->isDefined())7224          Function->setInstantiationIsPending(false);7225      }7226      // Definition of a PCH-ed template declaration may be available only in the TU.7227      if (!LocalOnly && LangOpts.PCHInstantiateTemplates &&7228          TUKind == TU_Prefix && Function->instantiationIsPending())7229        DelayedImplicitInstantiations.push_back(Inst);7230      else if (!AtEndOfTU && Function->instantiationIsPending() &&7231               !LocalInstantiation)7232        DelayedImplicitInstantiations.push_back(Inst);7233      continue;7234    }7235 7236    // Instantiate variable definitions7237    VarDecl *Var = cast<VarDecl>(Inst.first);7238 7239    assert((Var->isStaticDataMember() ||7240            isa<VarTemplateSpecializationDecl>(Var)) &&7241           "Not a static data member, nor a variable template"7242           " specialization?");7243 7244    // Don't try to instantiate declarations if the most recent redeclaration7245    // is invalid.7246    if (Var->getMostRecentDecl()->isInvalidDecl())7247      continue;7248 7249    // Check if the most recent declaration has changed the specialization kind7250    // and removed the need for implicit instantiation.7251    switch (Var->getMostRecentDecl()7252                ->getTemplateSpecializationKindForInstantiation()) {7253    case TSK_Undeclared:7254      llvm_unreachable("Cannot instantitiate an undeclared specialization.");7255    case TSK_ExplicitInstantiationDeclaration:7256    case TSK_ExplicitSpecialization:7257      continue;  // No longer need to instantiate this type.7258    case TSK_ExplicitInstantiationDefinition:7259      // We only need an instantiation if the pending instantiation *is* the7260      // explicit instantiation.7261      if (Var != Var->getMostRecentDecl())7262        continue;7263      break;7264    case TSK_ImplicitInstantiation:7265      break;7266    }7267 7268    PrettyDeclStackTraceEntry CrashInfo(Context, Var, SourceLocation(),7269                                        "instantiating variable definition");7270    bool DefinitionRequired = Var->getTemplateSpecializationKind() ==7271                              TSK_ExplicitInstantiationDefinition;7272 7273    // Instantiate static data member definitions or variable template7274    // specializations.7275    InstantiateVariableDefinition(/*FIXME:*/ Inst.second, Var, true,7276                                  DefinitionRequired, AtEndOfTU);7277  }7278 7279  if (!DelayedImplicitInstantiations.empty())7280    PendingInstantiations.swap(DelayedImplicitInstantiations);7281}7282 7283void Sema::PerformDependentDiagnostics(const DeclContext *Pattern,7284                       const MultiLevelTemplateArgumentList &TemplateArgs) {7285  for (auto *DD : Pattern->ddiags()) {7286    switch (DD->getKind()) {7287    case DependentDiagnostic::Access:7288      HandleDependentAccessCheck(*DD, TemplateArgs);7289      break;7290    }7291  }7292}7293