/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateInstantiate.cpp

Bug Summary

File:	src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateInstantiate.cpp
Warning:	line 2694, column 29 Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name SemaTemplateInstantiate.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include/clang/Sema -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libclangSema/../include -I /usr/src/gnu/usr.bin/clang/libclangSema/obj -I /usr/src/gnu/usr.bin/clang/libclangSema/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libclangSema/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -stack-protector 2 -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateInstantiate.cpp

/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/lib/Sema/SemaTemplateInstantiate.cpp

→

1//===------- SemaTemplateInstantiate.cpp - C++ Template 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-exception
6//===----------------------------------------------------------------------===/
7//
8//  This file implements C++ template instantiation.
9//
10//===----------------------------------------------------------------------===/

12#include "TreeTransform.h"
13#include "clang/AST/ASTConsumer.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/ASTLambda.h"
16#include "clang/AST/ASTMutationListener.h"
17#include "clang/AST/DeclTemplate.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/PrettyDeclStackTrace.h"
20#include "clang/AST/TypeVisitor.h"
21#include "clang/Basic/LangOptions.h"
22#include "clang/Basic/Stack.h"
23#include "clang/Basic/TargetInfo.h"
24#include "clang/Sema/DeclSpec.h"
25#include "clang/Sema/Initialization.h"
26#include "clang/Sema/Lookup.h"
27#include "clang/Sema/SemaConcept.h"
28#include "clang/Sema/SemaInternal.h"
29#include "clang/Sema/Template.h"
30#include "clang/Sema/TemplateDeduction.h"
31#include "clang/Sema/TemplateInstCallback.h"
32#include "llvm/Support/TimeProfiler.h"

34using namespace clang;
35using namespace sema;

37//===----------------------------------------------------------------------===/
38// Template Instantiation Support
39//===----------------------------------------------------------------------===/

41/// Retrieve the template argument list(s) that should be used to
42/// instantiate the definition of the given declaration.
43///
44/// \param D the declaration for which we are computing template instantiation
45/// arguments.
46///
47/// \param Innermost if non-NULL, the innermost template argument list.
48///
49/// \param RelativeToPrimary true if we should get the template
50/// arguments relative to the primary template, even when we're
51/// dealing with a specialization. This is only relevant for function
52/// template specializations.
53///
54/// \param Pattern If non-NULL, indicates the pattern from which we will be
55/// instantiating the definition of the given declaration, \p D. This is
56/// used to determine the proper set of template instantiation arguments for
57/// friend function template specializations.
58MultiLevelTemplateArgumentList
59Sema::getTemplateInstantiationArgs(NamedDecl *D,
                                 const TemplateArgumentList *Innermost,
                                 bool RelativeToPrimary,
                                 const FunctionDecl *Pattern) {
// Accumulate the set of template argument lists in this structure.
MultiLevelTemplateArgumentList Result;

if (Innermost)
  Result.addOuterTemplateArguments(Innermost);

DeclContext *Ctx = dyn_cast<DeclContext>(D);
if (!Ctx) {
  Ctx = D->getDeclContext();

  // Add template arguments from a variable template instantiation. For a
  // class-scope explicit specialization, there are no template arguments
  // at this level, but there may be enclosing template arguments.
  VarTemplateSpecializationDecl *Spec =
      dyn_cast<VarTemplateSpecializationDecl>(D);
  if (Spec && !Spec->isClassScopeExplicitSpecialization()) {
    // We're done when we hit an explicit specialization.
    if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
        !isa<VarTemplatePartialSpecializationDecl>(Spec))
      return Result;

    Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());

    // If this variable template specialization was instantiated from a
    // specialized member that is a variable template, we're done.
    assert(Spec->getSpecializedTemplate() && "No variable template?")((void)0);
    llvm::PointerUnion<VarTemplateDecl*,
                       VarTemplatePartialSpecializationDecl*> Specialized
                           = Spec->getSpecializedTemplateOrPartial();
    if (VarTemplatePartialSpecializationDecl *Partial =
            Specialized.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
      if (Partial->isMemberSpecialization())
        return Result;
    } else {
      VarTemplateDecl *Tmpl = Specialized.get<VarTemplateDecl *>();
      if (Tmpl->isMemberSpecialization())
        return Result;
    }
  }

  // If we have a template template parameter with translation unit context,
  // then we're performing substitution into a default template argument of
  // this template template parameter before we've constructed the template
  // that will own this template template parameter. In this case, we
  // use empty template parameter lists for all of the outer templates
  // to avoid performing any substitutions.
  if (Ctx->isTranslationUnit()) {
    if (TemplateTemplateParmDecl *TTP
                                    = dyn_cast<TemplateTemplateParmDecl>(D)) {
      for (unsigned I = 0, N = TTP->getDepth() + 1; I != N; ++I)
        Result.addOuterTemplateArguments(None);
      return Result;
    }
  }
}

while (!Ctx->isFileContext()) {
  // Add template arguments from a class template instantiation.
  ClassTemplateSpecializationDecl *Spec
        = dyn_cast<ClassTemplateSpecializationDecl>(Ctx);
  if (Spec && !Spec->isClassScopeExplicitSpecialization()) {
    // We're done when we hit an explicit specialization.
    if (Spec->getSpecializationKind() == TSK_ExplicitSpecialization &&
        !isa<ClassTemplatePartialSpecializationDecl>(Spec))
      break;

    Result.addOuterTemplateArguments(&Spec->getTemplateInstantiationArgs());

    // If this class template specialization was instantiated from a
    // specialized member that is a class template, we're done.
    assert(Spec->getSpecializedTemplate() && "No class template?")((void)0);
    if (Spec->getSpecializedTemplate()->isMemberSpecialization())
      break;
  }
  // Add template arguments from a function template specialization.
  else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Ctx)) {
    if (!RelativeToPrimary &&
        Function->getTemplateSpecializationKindForInstantiation() ==
            TSK_ExplicitSpecialization)
      break;

    if (!RelativeToPrimary && Function->getTemplateSpecializationKind() ==
                                  TSK_ExplicitSpecialization) {
      // This is an implicit instantiation of an explicit specialization. We
      // don't get any template arguments from this function but might get
      // some from an enclosing template.
    } else if (const TemplateArgumentList *TemplateArgs
          = Function->getTemplateSpecializationArgs()) {
      // Add the template arguments for this specialization.
      Result.addOuterTemplateArguments(TemplateArgs);

      // If this function was instantiated from a specialized member that is
      // a function template, we're done.
      assert(Function->getPrimaryTemplate() && "No function template?")((void)0);
      if (Function->getPrimaryTemplate()->isMemberSpecialization())
        break;

      // If this function is a generic lambda specialization, we are done.
      if (isGenericLambdaCallOperatorOrStaticInvokerSpecialization(Function))
        break;

    } else if (FunctionTemplateDecl *FunTmpl
                                 = Function->getDescribedFunctionTemplate()) {
      // Add the "injected" template arguments.
      Result.addOuterTemplateArguments(FunTmpl->getInjectedTemplateArgs());
    }

    // If this is a friend declaration and it declares an entity at
    // namespace scope, take arguments from its lexical parent
    // instead of its semantic parent, unless of course the pattern we're
    // instantiating actually comes from the file's context!
    if (Function->getFriendObjectKind() &&
        Function->getDeclContext()->isFileContext() &&
        (!Pattern || !Pattern->getLexicalDeclContext()->isFileContext())) {
      Ctx = Function->getLexicalDeclContext();
      RelativeToPrimary = false;
      continue;
    }
  } else if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Ctx)) {
    if (ClassTemplateDecl *ClassTemplate = Rec->getDescribedClassTemplate()) {
      QualType T = ClassTemplate->getInjectedClassNameSpecialization();
      const TemplateSpecializationType *TST =
          cast<TemplateSpecializationType>(Context.getCanonicalType(T));
      Result.addOuterTemplateArguments(
          llvm::makeArrayRef(TST->getArgs(), TST->getNumArgs()));
      if (ClassTemplate->isMemberSpecialization())
        break;
    }
  }

  Ctx = Ctx->getParent();
  RelativeToPrimary = false;
}

return Result;
198}

200bool Sema::CodeSynthesisContext::isInstantiationRecord() const {
switch (Kind) {
case TemplateInstantiation:
case ExceptionSpecInstantiation:
case DefaultTemplateArgumentInstantiation:
case DefaultFunctionArgumentInstantiation:
case ExplicitTemplateArgumentSubstitution:
case DeducedTemplateArgumentSubstitution:
case PriorTemplateArgumentSubstitution:
case ConstraintsCheck:
case NestedRequirementConstraintsCheck:
  return true;

case RequirementInstantiation:
case DefaultTemplateArgumentChecking:
case DeclaringSpecialMember:
case DeclaringImplicitEqualityComparison:
case DefiningSynthesizedFunction:
case ExceptionSpecEvaluation:
case ConstraintSubstitution:
case ParameterMappingSubstitution:
case ConstraintNormalization:
case RewritingOperatorAsSpaceship:
case InitializingStructuredBinding:
case MarkingClassDllexported:
  return false;

// This function should never be called when Kind's value is Memoization.
case Memoization:
  break;
}

llvm_unreachable("Invalid SynthesisKind!")__builtin_unreachable();
233}

235Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, CodeSynthesisContext::SynthesisKind Kind,
  SourceLocation PointOfInstantiation, SourceRange InstantiationRange,
  Decl *Entity, NamedDecl *Template, ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo *DeductionInfo)
  : SemaRef(SemaRef) {
// Don't allow further instantiation if a fatal error and an uncompilable
// error have occurred. Any diagnostics we might have raised will not be
// visible, and we do not need to construct a correct AST.
if (SemaRef.Diags.hasFatalErrorOccurred() &&
18
←
Assuming the condition is false→
    SemaRef.hasUncompilableErrorOccurred()) {
  Invalid = true;
  return;
}
Invalid = CheckInstantiationDepth(PointOfInstantiation, InstantiationRange);
19
←
Calling 'InstantiatingTemplate::CheckInstantiationDepth'→
23
←
Returning from 'InstantiatingTemplate::CheckInstantiationDepth'→
if (!Invalid23.1
Field 'Invalid' is false
1
Field 'Invalid' is false
) {
24
←
Taking true branch→
  CodeSynthesisContext Inst;
  Inst.Kind = Kind;
  Inst.PointOfInstantiation = PointOfInstantiation;
  Inst.Entity = Entity;
  Inst.Template = Template;
  Inst.TemplateArgs = TemplateArgs.data();
  Inst.NumTemplateArgs = TemplateArgs.size();
  Inst.DeductionInfo = DeductionInfo;
  Inst.InstantiationRange = InstantiationRange;
  SemaRef.pushCodeSynthesisContext(Inst);

  AlreadyInstantiating = !Inst.Entity24.1
Field 'Entity' is non-null
1
Field 'Entity' is non-null
 ? false :
25
←
'?' condition is false→
      !SemaRef.InstantiatingSpecializations
26
←
Assuming field 'second' is true→
           .insert({Inst.Entity->getCanonicalDecl(), Inst.Kind})
           .second;
  atTemplateBegin(SemaRef.TemplateInstCallbacks, SemaRef, Inst);
}
268}

270Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, Decl *Entity,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(SemaRef,
17
←
Calling constructor for 'InstantiatingTemplate'→
27
←
Returning from constructor for 'InstantiatingTemplate'→
                          CodeSynthesisContext::TemplateInstantiation,
                          PointOfInstantiation, InstantiationRange, Entity) {}

277Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, FunctionDecl *Entity,
  ExceptionSpecification, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ExceptionSpecInstantiation,
        PointOfInstantiation, InstantiationRange, Entity) {}

284Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateParameter Param,
  TemplateDecl *Template, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DefaultTemplateArgumentInstantiation,
        PointOfInstantiation, InstantiationRange, getAsNamedDecl(Param),
        Template, TemplateArgs) {}

294Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  FunctionTemplateDecl *FunctionTemplate,
  ArrayRef<TemplateArgument> TemplateArgs,
  CodeSynthesisContext::SynthesisKind Kind,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(SemaRef, Kind, PointOfInstantiation,
                          InstantiationRange, FunctionTemplate, nullptr,
                          TemplateArgs, &DeductionInfo) {
assert(((void)0)
  Kind == CodeSynthesisContext::ExplicitTemplateArgumentSubstitution ||((void)0)
  Kind == CodeSynthesisContext::DeducedTemplateArgumentSubstitution)((void)0);
306}

308Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  TemplateDecl *Template,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        TemplateArgs, &DeductionInfo) {}

319Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ClassTemplatePartialSpecializationDecl *PartialSpec,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, PartialSpec, nullptr,
        TemplateArgs, &DeductionInfo) {}

330Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  VarTemplatePartialSpecializationDecl *PartialSpec,
  ArrayRef<TemplateArgument> TemplateArgs,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DeducedTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, PartialSpec, nullptr,
        TemplateArgs, &DeductionInfo) {}

341Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, ParmVarDecl *Param,
  ArrayRef<TemplateArgument> TemplateArgs, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::DefaultFunctionArgumentInstantiation,
        PointOfInstantiation, InstantiationRange, Param, nullptr,
        TemplateArgs) {}

350Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template,
  NonTypeTemplateParmDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::PriorTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

360Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, NamedDecl *Template,
  TemplateTemplateParmDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef,
        CodeSynthesisContext::PriorTemplateArgumentSubstitution,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

370Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation, TemplateDecl *Template,
  NamedDecl *Param, ArrayRef<TemplateArgument> TemplateArgs,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::DefaultTemplateArgumentChecking,
        PointOfInstantiation, InstantiationRange, Param, Template,
        TemplateArgs) {}

379Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  concepts::Requirement *Req, sema::TemplateDeductionInfo &DeductionInfo,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::RequirementInstantiation,
        PointOfInstantiation, InstantiationRange, /*Entity=*/nullptr,
        /*Template=*/nullptr, /*TemplateArgs=*/None, &DeductionInfo) {}


389Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  concepts::NestedRequirement *Req, ConstraintsCheck,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::NestedRequirementConstraintsCheck,
        PointOfInstantiation, InstantiationRange, /*Entity=*/nullptr,
        /*Template=*/nullptr, /*TemplateArgs=*/None) {}


399Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintsCheck, NamedDecl *Template,
  ArrayRef<TemplateArgument> TemplateArgs, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintsCheck,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        TemplateArgs) {}

408Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintSubstitution, NamedDecl *Template,
  sema::TemplateDeductionInfo &DeductionInfo, SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintSubstitution,
        PointOfInstantiation, InstantiationRange, Template, nullptr,
        {}, &DeductionInfo) {}

417Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ConstraintNormalization, NamedDecl *Template,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ConstraintNormalization,
        PointOfInstantiation, InstantiationRange, Template) {}

425Sema::InstantiatingTemplate::InstantiatingTemplate(
  Sema &SemaRef, SourceLocation PointOfInstantiation,
  ParameterMappingSubstitution, NamedDecl *Template,
  SourceRange InstantiationRange)
  : InstantiatingTemplate(
        SemaRef, CodeSynthesisContext::ParameterMappingSubstitution,
        PointOfInstantiation, InstantiationRange, Template) {}

433void Sema::pushCodeSynthesisContext(CodeSynthesisContext Ctx) {
Ctx.SavedInNonInstantiationSFINAEContext = InNonInstantiationSFINAEContext;
InNonInstantiationSFINAEContext = false;

CodeSynthesisContexts.push_back(Ctx);

if (!Ctx.isInstantiationRecord())
  ++NonInstantiationEntries;

// Check to see if we're low on stack space. We can't do anything about this
// from here, but we can at least warn the user.
if (isStackNearlyExhausted())
  warnStackExhausted(Ctx.PointOfInstantiation);
446}

448void Sema::popCodeSynthesisContext() {
auto &Active = CodeSynthesisContexts.back();
if (!Active.isInstantiationRecord()) {
  assert(NonInstantiationEntries > 0)((void)0);
  --NonInstantiationEntries;
}

InNonInstantiationSFINAEContext = Active.SavedInNonInstantiationSFINAEContext;

// Name lookup no longer looks in this template's defining module.
assert(CodeSynthesisContexts.size() >=((void)0)
           CodeSynthesisContextLookupModules.size() &&((void)0)
       "forgot to remove a lookup module for a template instantiation")((void)0);
if (CodeSynthesisContexts.size() ==
    CodeSynthesisContextLookupModules.size()) {
  if (Module *M = CodeSynthesisContextLookupModules.back())
    LookupModulesCache.erase(M);
  CodeSynthesisContextLookupModules.pop_back();
}

// If we've left the code synthesis context for the current context stack,
// stop remembering that we've emitted that stack.
if (CodeSynthesisContexts.size() ==
    LastEmittedCodeSynthesisContextDepth)
  LastEmittedCodeSynthesisContextDepth = 0;

CodeSynthesisContexts.pop_back();
475}

477void Sema::InstantiatingTemplate::Clear() {
if (!Invalid) {
  if (!AlreadyInstantiating) {
    auto &Active = SemaRef.CodeSynthesisContexts.back();
    if (Active.Entity)
      SemaRef.InstantiatingSpecializations.erase(
          {Active.Entity->getCanonicalDecl(), Active.Kind});
  }

  atTemplateEnd(SemaRef.TemplateInstCallbacks, SemaRef,
                SemaRef.CodeSynthesisContexts.back());

  SemaRef.popCodeSynthesisContext();
  Invalid = true;
}
492}

494bool Sema::InstantiatingTemplate::CheckInstantiationDepth(
                                      SourceLocation PointOfInstantiation,
                                         SourceRange InstantiationRange) {
assert(SemaRef.NonInstantiationEntries <=((void)0)
       SemaRef.CodeSynthesisContexts.size())((void)0);
if ((SemaRef.CodeSynthesisContexts.size() -
20
←
Assuming the condition is true→
21
←
Taking true branch→
        SemaRef.NonInstantiationEntries)
      <= SemaRef.getLangOpts().InstantiationDepth)
  return false;
22
←
Returning zero, which participates in a condition later→

SemaRef.Diag(PointOfInstantiation,
             diag::err_template_recursion_depth_exceeded)
  << SemaRef.getLangOpts().InstantiationDepth
  << InstantiationRange;
SemaRef.Diag(PointOfInstantiation, diag::note_template_recursion_depth)
  << SemaRef.getLangOpts().InstantiationDepth;
return true;
511}

513/// Prints the current instantiation stack through a series of
514/// notes.
515void Sema::PrintInstantiationStack() {
// Determine which template instantiations to skip, if any.
unsigned SkipStart = CodeSynthesisContexts.size(), SkipEnd = SkipStart;
unsigned Limit = Diags.getTemplateBacktraceLimit();
if (Limit && Limit < CodeSynthesisContexts.size()) {
  SkipStart = Limit / 2 + Limit % 2;
  SkipEnd = CodeSynthesisContexts.size() - Limit / 2;
}

// FIXME: In all of these cases, we need to show the template arguments
unsigned InstantiationIdx = 0;
for (SmallVectorImpl<CodeSynthesisContext>::reverse_iterator
       Active = CodeSynthesisContexts.rbegin(),
       ActiveEnd = CodeSynthesisContexts.rend();
     Active != ActiveEnd;
     ++Active, ++InstantiationIdx) {
  // Skip this instantiation?
  if (InstantiationIdx >= SkipStart && InstantiationIdx < SkipEnd) {
    if (InstantiationIdx == SkipStart) {
      // Note that we're skipping instantiations.
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_instantiation_contexts_suppressed)
        << unsigned(CodeSynthesisContexts.size() - Limit);
    }
    continue;
  }

  switch (Active->Kind) {
  case CodeSynthesisContext::TemplateInstantiation: {
    Decl *D = Active->Entity;
    if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
      unsigned DiagID = diag::note_template_member_class_here;
      if (isa<ClassTemplateSpecializationDecl>(Record))
        DiagID = diag::note_template_class_instantiation_here;
      Diags.Report(Active->PointOfInstantiation, DiagID)
        << Record << Active->InstantiationRange;
    } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
      unsigned DiagID;
      if (Function->getPrimaryTemplate())
        DiagID = diag::note_function_template_spec_here;
      else
        DiagID = diag::note_template_member_function_here;
      Diags.Report(Active->PointOfInstantiation, DiagID)
        << Function
        << Active->InstantiationRange;
    } else if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   VD->isStaticDataMember()?
                     diag::note_template_static_data_member_def_here
                   : diag::note_template_variable_def_here)
        << VD
        << Active->InstantiationRange;
    } else if (EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_enum_def_here)
        << ED
        << Active->InstantiationRange;
    } else if (FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_nsdmi_here)
          << FD << Active->InstantiationRange;
    } else {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_template_type_alias_instantiation_here)
        << cast<TypeAliasTemplateDecl>(D)
        << Active->InstantiationRange;
    }
    break;
  }

  case CodeSynthesisContext::DefaultTemplateArgumentInstantiation: {
    TemplateDecl *Template = cast<TemplateDecl>(Active->Template);
    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    Template->printName(OS);
    printTemplateArgumentList(OS, Active->template_arguments(),
                              getPrintingPolicy());
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_default_arg_instantiation_here)
      << OS.str()
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::ExplicitTemplateArgumentSubstitution: {
    FunctionTemplateDecl *FnTmpl = cast<FunctionTemplateDecl>(Active->Entity);
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_explicit_template_arg_substitution_here)
      << FnTmpl
      << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::DeducedTemplateArgumentSubstitution: {
    if (FunctionTemplateDecl *FnTmpl =
            dyn_cast<FunctionTemplateDecl>(Active->Entity)) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_function_template_deduction_instantiation_here)
        << FnTmpl
        << getTemplateArgumentBindingsText(FnTmpl->getTemplateParameters(),
                                           Active->TemplateArgs,
                                           Active->NumTemplateArgs)
        << Active->InstantiationRange;
    } else {
      bool IsVar = isa<VarTemplateDecl>(Active->Entity) ||
                   isa<VarTemplateSpecializationDecl>(Active->Entity);
      bool IsTemplate = false;
      TemplateParameterList *Params;
      if (auto *D = dyn_cast<TemplateDecl>(Active->Entity)) {
        IsTemplate = true;
        Params = D->getTemplateParameters();
      } else if (auto *D = dyn_cast<ClassTemplatePartialSpecializationDecl>(
                     Active->Entity)) {
        Params = D->getTemplateParameters();
      } else if (auto *D = dyn_cast<VarTemplatePartialSpecializationDecl>(
                     Active->Entity)) {
        Params = D->getTemplateParameters();
      } else {
        llvm_unreachable("unexpected template kind")__builtin_unreachable();
      }

      Diags.Report(Active->PointOfInstantiation,
                   diag::note_deduced_template_arg_substitution_here)
        << IsVar << IsTemplate << cast<NamedDecl>(Active->Entity)
        << getTemplateArgumentBindingsText(Params, Active->TemplateArgs,
                                           Active->NumTemplateArgs)
        << Active->InstantiationRange;
    }
    break;
  }

  case CodeSynthesisContext::DefaultFunctionArgumentInstantiation: {
    ParmVarDecl *Param = cast<ParmVarDecl>(Active->Entity);
    FunctionDecl *FD = cast<FunctionDecl>(Param->getDeclContext());

    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    FD->printName(OS);
    printTemplateArgumentList(OS, Active->template_arguments(),
                              getPrintingPolicy());
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_default_function_arg_instantiation_here)
      << OS.str()
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::PriorTemplateArgumentSubstitution: {
    NamedDecl *Parm = cast<NamedDecl>(Active->Entity);
    std::string Name;
    if (!Parm->getName().empty())
      Name = std::string(" '") + Parm->getName().str() + "'";

    TemplateParameterList *TemplateParams = nullptr;
    if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
      TemplateParams = Template->getTemplateParameters();
    else
      TemplateParams =
        cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
                                                    ->getTemplateParameters();
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_prior_template_arg_substitution)
      << isa<TemplateTemplateParmDecl>(Parm)
      << Name
      << getTemplateArgumentBindingsText(TemplateParams,
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::DefaultTemplateArgumentChecking: {
    TemplateParameterList *TemplateParams = nullptr;
    if (TemplateDecl *Template = dyn_cast<TemplateDecl>(Active->Template))
      TemplateParams = Template->getTemplateParameters();
    else
      TemplateParams =
        cast<ClassTemplatePartialSpecializationDecl>(Active->Template)
                                                    ->getTemplateParameters();

    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_default_arg_checking)
      << getTemplateArgumentBindingsText(TemplateParams,
                                         Active->TemplateArgs,
                                         Active->NumTemplateArgs)
      << Active->InstantiationRange;
    break;
  }

  case CodeSynthesisContext::ExceptionSpecEvaluation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_evaluating_exception_spec_here)
        << cast<FunctionDecl>(Active->Entity);
    break;

  case CodeSynthesisContext::ExceptionSpecInstantiation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_exception_spec_instantiation_here)
      << cast<FunctionDecl>(Active->Entity)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::RequirementInstantiation:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_template_requirement_instantiation_here)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::NestedRequirementConstraintsCheck:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_nested_requirement_here)
      << Active->InstantiationRange;
    break;

  case CodeSynthesisContext::DeclaringSpecialMember:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_in_declaration_of_implicit_special_member)
      << cast<CXXRecordDecl>(Active->Entity) << Active->SpecialMember;
    break;

  case CodeSynthesisContext::DeclaringImplicitEqualityComparison:
    Diags.Report(Active->Entity->getLocation(),
                 diag::note_in_declaration_of_implicit_equality_comparison);
    break;

  case CodeSynthesisContext::DefiningSynthesizedFunction: {
    // FIXME: For synthesized functions that are not defaulted,
    // produce a note.
    auto *FD = dyn_cast<FunctionDecl>(Active->Entity);
    DefaultedFunctionKind DFK =
        FD ? getDefaultedFunctionKind(FD) : DefaultedFunctionKind();
    if (DFK.isSpecialMember()) {
      auto *MD = cast<CXXMethodDecl>(FD);
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_member_synthesized_at)
          << MD->isExplicitlyDefaulted() << DFK.asSpecialMember()
          << Context.getTagDeclType(MD->getParent());
    } else if (DFK.isComparison()) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_comparison_synthesized_at)
          << (int)DFK.asComparison()
          << Context.getTagDeclType(
                 cast<CXXRecordDecl>(FD->getLexicalDeclContext()));
    }
    break;
  }

  case CodeSynthesisContext::RewritingOperatorAsSpaceship:
    Diags.Report(Active->Entity->getLocation(),
                 diag::note_rewriting_operator_as_spaceship);
    break;

  case CodeSynthesisContext::InitializingStructuredBinding:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_in_binding_decl_init)
        << cast<BindingDecl>(Active->Entity);
    break;

  case CodeSynthesisContext::MarkingClassDllexported:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_due_to_dllexported_class)
        << cast<CXXRecordDecl>(Active->Entity) << !getLangOpts().CPlusPlus11;
    break;

  case CodeSynthesisContext::Memoization:
    break;

  case CodeSynthesisContext::ConstraintsCheck: {
    unsigned DiagID = 0;
    if (!Active->Entity) {
      Diags.Report(Active->PointOfInstantiation,
                   diag::note_nested_requirement_here)
        << Active->InstantiationRange;
      break;
    }
    if (isa<ConceptDecl>(Active->Entity))
      DiagID = diag::note_concept_specialization_here;
    else if (isa<TemplateDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_template_id_here;
    else if (isa<VarTemplatePartialSpecializationDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_var_spec_id_here;
    else if (isa<ClassTemplatePartialSpecializationDecl>(Active->Entity))
      DiagID = diag::note_checking_constraints_for_class_spec_id_here;
    else {
      assert(isa<FunctionDecl>(Active->Entity))((void)0);
      DiagID = diag::note_checking_constraints_for_function_here;
    }
    SmallString<128> TemplateArgsStr;
    llvm::raw_svector_ostream OS(TemplateArgsStr);
    cast<NamedDecl>(Active->Entity)->printName(OS);
    if (!isa<FunctionDecl>(Active->Entity)) {
      printTemplateArgumentList(OS, Active->template_arguments(),
                                getPrintingPolicy());
    }
    Diags.Report(Active->PointOfInstantiation, DiagID) << OS.str()
      << Active->InstantiationRange;
    break;
  }
  case CodeSynthesisContext::ConstraintSubstitution:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_constraint_substitution_here)
        << Active->InstantiationRange;
    break;
  case CodeSynthesisContext::ConstraintNormalization:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_constraint_normalization_here)
        << cast<NamedDecl>(Active->Entity)->getName()
        << Active->InstantiationRange;
    break;
  case CodeSynthesisContext::ParameterMappingSubstitution:
    Diags.Report(Active->PointOfInstantiation,
                 diag::note_parameter_mapping_substitution_here)
        << Active->InstantiationRange;
    break;
  }
}
834}

836Optional<TemplateDeductionInfo *> Sema::isSFINAEContext() const {
if (InNonInstantiationSFINAEContext)
  return Optional<TemplateDeductionInfo *>(nullptr);

for (SmallVectorImpl<CodeSynthesisContext>::const_reverse_iterator
       Active = CodeSynthesisContexts.rbegin(),
       ActiveEnd = CodeSynthesisContexts.rend();
     Active != ActiveEnd;
     ++Active)
{
  switch (Active->Kind) {
  case CodeSynthesisContext::TemplateInstantiation:
    // An instantiation of an alias template may or may not be a SFINAE
    // context, depending on what else is on the stack.
    if (isa<TypeAliasTemplateDecl>(Active->Entity))
      break;
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case CodeSynthesisContext::DefaultFunctionArgumentInstantiation:
  case CodeSynthesisContext::ExceptionSpecInstantiation:
  case CodeSynthesisContext::ConstraintsCheck:
  case CodeSynthesisContext::ParameterMappingSubstitution:
  case CodeSynthesisContext::ConstraintNormalization:
  case CodeSynthesisContext::NestedRequirementConstraintsCheck:
    // This is a template instantiation, so there is no SFINAE.
    return None;

  case CodeSynthesisContext::DefaultTemplateArgumentInstantiation:
  case CodeSynthesisContext::PriorTemplateArgumentSubstitution:
  case CodeSynthesisContext::DefaultTemplateArgumentChecking:
  case CodeSynthesisContext::RewritingOperatorAsSpaceship:
    // A default template argument instantiation and substitution into
    // template parameters with arguments for prior parameters may or may
    // not be a SFINAE context; look further up the stack.
    break;

  case CodeSynthesisContext::ExplicitTemplateArgumentSubstitution:
  case CodeSynthesisContext::DeducedTemplateArgumentSubstitution:
  case CodeSynthesisContext::ConstraintSubstitution:
  case CodeSynthesisContext::RequirementInstantiation:
    // We're either substituting explicitly-specified template arguments,
    // deduced template arguments, a constraint expression or a requirement
    // in a requires expression, so SFINAE applies.
    assert(Active->DeductionInfo && "Missing deduction info pointer")((void)0);
    return Active->DeductionInfo;

  case CodeSynthesisContext::DeclaringSpecialMember:
  case CodeSynthesisContext::DeclaringImplicitEqualityComparison:
  case CodeSynthesisContext::DefiningSynthesizedFunction:
  case CodeSynthesisContext::InitializingStructuredBinding:
  case CodeSynthesisContext::MarkingClassDllexported:
    // This happens in a context unrelated to template instantiation, so
    // there is no SFINAE.
    return None;

  case CodeSynthesisContext::ExceptionSpecEvaluation:
    // FIXME: This should not be treated as a SFINAE context, because
    // we will cache an incorrect exception specification. However, clang
    // bootstrap relies this! See PR31692.
    break;

  case CodeSynthesisContext::Memoization:
    break;
  }

  // The inner context was transparent for SFINAE. If it occurred within a
  // non-instantiation SFINAE context, then SFINAE applies.
  if (Active->SavedInNonInstantiationSFINAEContext)
    return Optional<TemplateDeductionInfo *>(nullptr);
}

return None;
907}

909//===----------------------------------------------------------------------===/
910// Template Instantiation for Types
911//===----------------------------------------------------------------------===/
912namespace {
class TemplateInstantiator : public TreeTransform<TemplateInstantiator> {
  const MultiLevelTemplateArgumentList &TemplateArgs;
  SourceLocation Loc;
  DeclarationName Entity;

public:
  typedef TreeTransform<TemplateInstantiator> inherited;

  TemplateInstantiator(Sema &SemaRef,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       SourceLocation Loc,
                       DeclarationName Entity)
    : inherited(SemaRef), TemplateArgs(TemplateArgs), Loc(Loc),
      Entity(Entity) { }

  /// Determine whether the given type \p T has already been
  /// transformed.
  ///
  /// For the purposes of template instantiation, a type has already been
  /// transformed if it is NULL or if it is not dependent.
  bool AlreadyTransformed(QualType T);

  /// Returns the location of the entity being instantiated, if known.
  SourceLocation getBaseLocation() { return Loc; }

  /// Returns the name of the entity being instantiated, if any.
  DeclarationName getBaseEntity() { return Entity; }

  /// Sets the "base" location and entity when that
  /// information is known based on another transformation.
  void setBase(SourceLocation Loc, DeclarationName Entity) {
    this->Loc = Loc;
    this->Entity = Entity;
  }

  unsigned TransformTemplateDepth(unsigned Depth) {
    return TemplateArgs.getNewDepth(Depth);
  }

  bool TryExpandParameterPacks(SourceLocation EllipsisLoc,
                               SourceRange PatternRange,
                               ArrayRef<UnexpandedParameterPack> Unexpanded,
                               bool &ShouldExpand, bool &RetainExpansion,
                               Optional<unsigned> &NumExpansions) {
    return getSema().CheckParameterPacksForExpansion(EllipsisLoc,
                                                     PatternRange, Unexpanded,
                                                     TemplateArgs,
                                                     ShouldExpand,
                                                     RetainExpansion,
                                                     NumExpansions);
  }

  void ExpandingFunctionParameterPack(ParmVarDecl *Pack) {
    SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Pack);
  }

  TemplateArgument ForgetPartiallySubstitutedPack() {
    TemplateArgument Result;
    if (NamedDecl *PartialPack
          = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
      MultiLevelTemplateArgumentList &TemplateArgs
        = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
      unsigned Depth, Index;
      std::tie(Depth, Index) = getDepthAndIndex(PartialPack);
      if (TemplateArgs.hasTemplateArgument(Depth, Index)) {
        Result = TemplateArgs(Depth, Index);
        TemplateArgs.setArgument(Depth, Index, TemplateArgument());
      }
    }

    return Result;
  }

  void RememberPartiallySubstitutedPack(TemplateArgument Arg) {
    if (Arg.isNull())
      return;

    if (NamedDecl *PartialPack
          = SemaRef.CurrentInstantiationScope->getPartiallySubstitutedPack()){
      MultiLevelTemplateArgumentList &TemplateArgs
      = const_cast<MultiLevelTemplateArgumentList &>(this->TemplateArgs);
      unsigned Depth, Index;
      std::tie(Depth, Index) = getDepthAndIndex(PartialPack);
      TemplateArgs.setArgument(Depth, Index, Arg);
    }
  }

  /// Transform the given declaration by instantiating a reference to
  /// this declaration.
  Decl *TransformDecl(SourceLocation Loc, Decl *D);

  void transformAttrs(Decl *Old, Decl *New) {
    SemaRef.InstantiateAttrs(TemplateArgs, Old, New);
  }

  void transformedLocalDecl(Decl *Old, ArrayRef<Decl *> NewDecls) {
    if (Old->isParameterPack()) {
      SemaRef.CurrentInstantiationScope->MakeInstantiatedLocalArgPack(Old);
      for (auto *New : NewDecls)
        SemaRef.CurrentInstantiationScope->InstantiatedLocalPackArg(
            Old, cast<VarDecl>(New));
      return;
    }

    assert(NewDecls.size() == 1 &&((void)0)
           "should only have multiple expansions for a pack")((void)0);
    Decl *New = NewDecls.front();

    // If we've instantiated the call operator of a lambda or the call
    // operator template of a generic lambda, update the "instantiation of"
    // information.
    auto *NewMD = dyn_cast<CXXMethodDecl>(New);
    if (NewMD && isLambdaCallOperator(NewMD)) {
      auto *OldMD = dyn_cast<CXXMethodDecl>(Old);
      if (auto *NewTD = NewMD->getDescribedFunctionTemplate())
        NewTD->setInstantiatedFromMemberTemplate(
            OldMD->getDescribedFunctionTemplate());
      else
        NewMD->setInstantiationOfMemberFunction(OldMD,
                                                TSK_ImplicitInstantiation);
    }

    SemaRef.CurrentInstantiationScope->InstantiatedLocal(Old, New);

    // We recreated a local declaration, but not by instantiating it. There
    // may be pending dependent diagnostics to produce.
    if (auto *DC = dyn_cast<DeclContext>(Old))
      SemaRef.PerformDependentDiagnostics(DC, TemplateArgs);
  }

  /// Transform the definition of the given declaration by
  /// instantiating it.
  Decl *TransformDefinition(SourceLocation Loc, Decl *D);

  /// Transform the first qualifier within a scope by instantiating the
  /// declaration.
  NamedDecl *TransformFirstQualifierInScope(NamedDecl *D, SourceLocation Loc);

  /// Rebuild the exception declaration and register the declaration
  /// as an instantiated local.
  VarDecl *RebuildExceptionDecl(VarDecl *ExceptionDecl,
                                TypeSourceInfo *Declarator,
                                SourceLocation StartLoc,
                                SourceLocation NameLoc,
                                IdentifierInfo *Name);

  /// Rebuild the Objective-C exception declaration and register the
  /// declaration as an instantiated local.
  VarDecl *RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
                                    TypeSourceInfo *TSInfo, QualType T);

  /// Check for tag mismatches when instantiating an
  /// elaborated type.
  QualType RebuildElaboratedType(SourceLocation KeywordLoc,
                                 ElaboratedTypeKeyword Keyword,
                                 NestedNameSpecifierLoc QualifierLoc,
                                 QualType T);

  TemplateName
  TransformTemplateName(CXXScopeSpec &SS, TemplateName Name,
                        SourceLocation NameLoc,
                        QualType ObjectType = QualType(),
                        NamedDecl *FirstQualifierInScope = nullptr,
                        bool AllowInjectedClassName = false);

  const LoopHintAttr *TransformLoopHintAttr(const LoopHintAttr *LH);

  ExprResult TransformPredefinedExpr(PredefinedExpr *E);
  ExprResult TransformDeclRefExpr(DeclRefExpr *E);
  ExprResult TransformCXXDefaultArgExpr(CXXDefaultArgExpr *E);

  ExprResult TransformTemplateParmRefExpr(DeclRefExpr *E,
                                          NonTypeTemplateParmDecl *D);
  ExprResult TransformSubstNonTypeTemplateParmPackExpr(
                                         SubstNonTypeTemplateParmPackExpr *E);
  ExprResult TransformSubstNonTypeTemplateParmExpr(
                                         SubstNonTypeTemplateParmExpr *E);

  /// Rebuild a DeclRefExpr for a VarDecl reference.
  ExprResult RebuildVarDeclRefExpr(VarDecl *PD, SourceLocation Loc);

  /// Transform a reference to a function or init-capture parameter pack.
  ExprResult TransformFunctionParmPackRefExpr(DeclRefExpr *E, VarDecl *PD);

  /// Transform a FunctionParmPackExpr which was built when we couldn't
  /// expand a function parameter pack reference which refers to an expanded
  /// pack.
  ExprResult TransformFunctionParmPackExpr(FunctionParmPackExpr *E);

  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
                                      FunctionProtoTypeLoc TL) {
    // Call the base version; it will forward to our overridden version below.
    return inherited::TransformFunctionProtoType(TLB, TL);
  }

  template<typename Fn>
  QualType TransformFunctionProtoType(TypeLocBuilder &TLB,
                                      FunctionProtoTypeLoc TL,
                                      CXXRecordDecl *ThisContext,
                                      Qualifiers ThisTypeQuals,
                                      Fn TransformExceptionSpec);

  ParmVarDecl *TransformFunctionTypeParam(ParmVarDecl *OldParm,
                                          int indexAdjustment,
                                          Optional<unsigned> NumExpansions,
                                          bool ExpectParameterPack);

  /// Transforms a template type parameter type by performing
  /// substitution of the corresponding template type argument.
  QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                         TemplateTypeParmTypeLoc TL);

  /// Transforms an already-substituted template type parameter pack
  /// into either itself (if we aren't substituting into its pack expansion)
  /// or the appropriate substituted argument.
  QualType TransformSubstTemplateTypeParmPackType(TypeLocBuilder &TLB,
                                         SubstTemplateTypeParmPackTypeLoc TL);

  ExprResult TransformLambdaExpr(LambdaExpr *E) {
    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
    return TreeTransform<TemplateInstantiator>::TransformLambdaExpr(E);
  }

  ExprResult TransformRequiresExpr(RequiresExpr *E) {
    LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
    return TreeTransform<TemplateInstantiator>::TransformRequiresExpr(E);
  }

  bool TransformRequiresExprRequirements(
      ArrayRef<concepts::Requirement *> Reqs,
      SmallVectorImpl<concepts::Requirement *> &Transformed) {
    bool SatisfactionDetermined = false;
    for (concepts::Requirement *Req : Reqs) {
      concepts::Requirement *TransReq = nullptr;
      if (!SatisfactionDetermined) {
        if (auto *TypeReq = dyn_cast<concepts::TypeRequirement>(Req))
          TransReq = TransformTypeRequirement(TypeReq);
        else if (auto *ExprReq = dyn_cast<concepts::ExprRequirement>(Req))
          TransReq = TransformExprRequirement(ExprReq);
        else
          TransReq = TransformNestedRequirement(
              cast<concepts::NestedRequirement>(Req));
        if (!TransReq)
          return true;
        if (!TransReq->isDependent() && !TransReq->isSatisfied())
          // [expr.prim.req]p6
          //   [...]  The substitution and semantic constraint checking
          //   proceeds in lexical order and stops when a condition that
          //   determines the result of the requires-expression is
          //   encountered. [..]
          SatisfactionDetermined = true;
      } else
        TransReq = Req;
      Transformed.push_back(TransReq);
    }
    return false;
  }

  TemplateParameterList *TransformTemplateParameterList(
                            TemplateParameterList *OrigTPL)  {
    if (!OrigTPL || !OrigTPL->size()) return OrigTPL;

    DeclContext *Owner = OrigTPL->getParam(0)->getDeclContext();
    TemplateDeclInstantiator  DeclInstantiator(getSema(),
                      /* DeclContext *Owner */ Owner, TemplateArgs);
    return DeclInstantiator.SubstTemplateParams(OrigTPL);
  }

  concepts::TypeRequirement *
  TransformTypeRequirement(concepts::TypeRequirement *Req);
  concepts::ExprRequirement *
  TransformExprRequirement(concepts::ExprRequirement *Req);
  concepts::NestedRequirement *
  TransformNestedRequirement(concepts::NestedRequirement *Req);

private:
  ExprResult transformNonTypeTemplateParmRef(NonTypeTemplateParmDecl *parm,
                                             SourceLocation loc,
                                             TemplateArgument arg);
};
1193}

1195bool TemplateInstantiator::AlreadyTransformed(QualType T) {
if (T.isNull())
  return true;

if (T->isInstantiationDependentType() || T->isVariablyModifiedType())
  return false;

getSema().MarkDeclarationsReferencedInType(Loc, T);
return true;
1204}

1206static TemplateArgument
1207getPackSubstitutedTemplateArgument(Sema &S, TemplateArgument Arg) {
assert(S.ArgumentPackSubstitutionIndex >= 0)((void)0);
assert(S.ArgumentPackSubstitutionIndex < (int)Arg.pack_size())((void)0);
Arg = Arg.pack_begin()[S.ArgumentPackSubstitutionIndex];
if (Arg.isPackExpansion())
  Arg = Arg.getPackExpansionPattern();
return Arg;
1214}

1216Decl *TemplateInstantiator::TransformDecl(SourceLocation Loc, Decl *D) {
if (!D)
  return nullptr;

if (TemplateTemplateParmDecl *TTP = dyn_cast<TemplateTemplateParmDecl>(D)) {
  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // If the corresponding template argument is NULL or non-existent, it's
    // because we are performing instantiation from explicitly-specified
    // template arguments in a function template, but there were some
    // arguments left unspecified.
    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
                                          TTP->getPosition()))
      return D;

    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
             "Missing argument pack")((void)0);
      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    TemplateName Template = Arg.getAsTemplate().getNameToSubstitute();
    assert(!Template.isNull() && Template.getAsTemplateDecl() &&((void)0)
           "Wrong kind of template template argument")((void)0);
    return Template.getAsTemplateDecl();
  }

  // Fall through to find the instantiated declaration for this template
  // template parameter.
}

return SemaRef.FindInstantiatedDecl(Loc, cast<NamedDecl>(D), TemplateArgs);
1249}

1251Decl *TemplateInstantiator::TransformDefinition(SourceLocation Loc, Decl *D) {
Decl *Inst = getSema().SubstDecl(D, getSema().CurContext, TemplateArgs);
if (!Inst)
  return nullptr;

getSema().CurrentInstantiationScope->InstantiatedLocal(D, Inst);
return Inst;
1258}

1260NamedDecl *
1261TemplateInstantiator::TransformFirstQualifierInScope(NamedDecl *D,
                                                   SourceLocation Loc) {
// If the first part of the nested-name-specifier was a template type
// parameter, instantiate that type parameter down to a tag type.
if (TemplateTypeParmDecl *TTPD = dyn_cast_or_null<TemplateTypeParmDecl>(D)) {
  const TemplateTypeParmType *TTP
    = cast<TemplateTypeParmType>(getSema().Context.getTypeDeclType(TTPD));

  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // FIXME: This needs testing w/ member access expressions.
    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getIndex());

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
             "Missing argument pack")((void)0);

      if (getSema().ArgumentPackSubstitutionIndex == -1)
        return nullptr;

      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    QualType T = Arg.getAsType();
    if (T.isNull())
      return cast_or_null<NamedDecl>(TransformDecl(Loc, D));

    if (const TagType *Tag = T->getAs<TagType>())
      return Tag->getDecl();

    // The resulting type is not a tag; complain.
    getSema().Diag(Loc, diag::err_nested_name_spec_non_tag) << T;
    return nullptr;
  }
}

return cast_or_null<NamedDecl>(TransformDecl(Loc, D));
1297}

1299VarDecl *
1300TemplateInstantiator::RebuildExceptionDecl(VarDecl *ExceptionDecl,
                                         TypeSourceInfo *Declarator,
                                         SourceLocation StartLoc,
                                         SourceLocation NameLoc,
                                         IdentifierInfo *Name) {
VarDecl *Var = inherited::RebuildExceptionDecl(ExceptionDecl, Declarator,
                                               StartLoc, NameLoc, Name);
if (Var)
  getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
return Var;
1310}

1312VarDecl *TemplateInstantiator::RebuildObjCExceptionDecl(VarDecl *ExceptionDecl,
                                                      TypeSourceInfo *TSInfo,
                                                      QualType T) {
VarDecl *Var = inherited::RebuildObjCExceptionDecl(ExceptionDecl, TSInfo, T);
if (Var)
  getSema().CurrentInstantiationScope->InstantiatedLocal(ExceptionDecl, Var);
return Var;
1319}

1321QualType
1322TemplateInstantiator::RebuildElaboratedType(SourceLocation KeywordLoc,
                                          ElaboratedTypeKeyword Keyword,
                                          NestedNameSpecifierLoc QualifierLoc,
                                          QualType T) {
if (const TagType *TT = T->getAs<TagType>()) {
  TagDecl* TD = TT->getDecl();

  SourceLocation TagLocation = KeywordLoc;

  IdentifierInfo *Id = TD->getIdentifier();

  // TODO: should we even warn on struct/class mismatches for this?  Seems
  // like it's likely to produce a lot of spurious errors.
  if (Id && Keyword != ETK_None && Keyword != ETK_Typename) {
    TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForKeyword(Keyword);
    if (!SemaRef.isAcceptableTagRedeclaration(TD, Kind, /*isDefinition*/false,
                                              TagLocation, Id)) {
      SemaRef.Diag(TagLocation, diag::err_use_with_wrong_tag)
        << Id
        << FixItHint::CreateReplacement(SourceRange(TagLocation),
                                        TD->getKindName());
      SemaRef.Diag(TD->getLocation(), diag::note_previous_use);
    }
  }
}

return TreeTransform<TemplateInstantiator>::RebuildElaboratedType(KeywordLoc,
                                                                  Keyword,
                                                                QualifierLoc,
                                                                  T);
1352}

1354TemplateName TemplateInstantiator::TransformTemplateName(
  CXXScopeSpec &SS, TemplateName Name, SourceLocation NameLoc,
  QualType ObjectType, NamedDecl *FirstQualifierInScope,
  bool AllowInjectedClassName) {
if (TemplateTemplateParmDecl *TTP
     = dyn_cast_or_null<TemplateTemplateParmDecl>(Name.getAsTemplateDecl())) {
  if (TTP->getDepth() < TemplateArgs.getNumLevels()) {
    // If the corresponding template argument is NULL or non-existent, it's
    // because we are performing instantiation from explicitly-specified
    // template arguments in a function template, but there were some
    // arguments left unspecified.
    if (!TemplateArgs.hasTemplateArgument(TTP->getDepth(),
                                          TTP->getPosition()))
      return Name;

    TemplateArgument Arg = TemplateArgs(TTP->getDepth(), TTP->getPosition());

    if (TemplateArgs.isRewrite()) {
      // We're rewriting the template parameter as a reference to another
      // template parameter.
      if (Arg.getKind() == TemplateArgument::Pack) {
        assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&((void)0)
               "unexpected pack arguments in template rewrite")((void)0);
        Arg = Arg.pack_begin()->getPackExpansionPattern();
      }
      assert(Arg.getKind() == TemplateArgument::Template &&((void)0)
             "unexpected nontype template argument kind in template rewrite")((void)0);
      return Arg.getAsTemplate();
    }

    if (TTP->isParameterPack()) {
      assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
             "Missing argument pack")((void)0);

      if (getSema().ArgumentPackSubstitutionIndex == -1) {
        // We have the template argument pack to substitute, but we're not
        // actually expanding the enclosing pack expansion yet. So, just
        // keep the entire argument pack.
        return getSema().Context.getSubstTemplateTemplateParmPack(TTP, Arg);
      }

      Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
    }

    TemplateName Template = Arg.getAsTemplate().getNameToSubstitute();
    assert(!Template.isNull() && "Null template template argument")((void)0);
    assert(!Template.getAsQualifiedTemplateName() &&((void)0)
           "template decl to substitute is qualified?")((void)0);

    Template = getSema().Context.getSubstTemplateTemplateParm(TTP, Template);
    return Template;
  }
}

if (SubstTemplateTemplateParmPackStorage *SubstPack
    = Name.getAsSubstTemplateTemplateParmPack()) {
  if (getSema().ArgumentPackSubstitutionIndex == -1)
    return Name;

  TemplateArgument Arg = SubstPack->getArgumentPack();
  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
  return Arg.getAsTemplate().getNameToSubstitute();
}

return inherited::TransformTemplateName(SS, Name, NameLoc, ObjectType,
                                        FirstQualifierInScope,
                                        AllowInjectedClassName);
1421}

1423ExprResult
1424TemplateInstantiator::TransformPredefinedExpr(PredefinedExpr *E) {
if (!E->isTypeDependent())
  return E;

return getSema().BuildPredefinedExpr(E->getLocation(), E->getIdentKind());
1429}

1431ExprResult
1432TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
                                             NonTypeTemplateParmDecl *NTTP) {
// If the corresponding template argument is NULL or non-existent, it's
// because we are performing instantiation from explicitly-specified
// template arguments in a function template, but there were some
// arguments left unspecified.
if (!TemplateArgs.hasTemplateArgument(NTTP->getDepth(),
                                      NTTP->getPosition()))
  return E;

TemplateArgument Arg = TemplateArgs(NTTP->getDepth(), NTTP->getPosition());

if (TemplateArgs.isRewrite()) {
  // We're rewriting the template parameter as a reference to another
  // template parameter.
  if (Arg.getKind() == TemplateArgument::Pack) {
    assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&((void)0)
           "unexpected pack arguments in template rewrite")((void)0);
    Arg = Arg.pack_begin()->getPackExpansionPattern();
  }
  assert(Arg.getKind() == TemplateArgument::Expression &&((void)0)
         "unexpected nontype template argument kind in template rewrite")((void)0);
  // FIXME: This can lead to the same subexpression appearing multiple times
  // in a complete expression.
  return Arg.getAsExpr();
}

if (NTTP->isParameterPack()) {
  assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
         "Missing argument pack")((void)0);

  if (getSema().ArgumentPackSubstitutionIndex == -1) {
    // We have an argument pack, but we can't select a particular argument
    // out of it yet. Therefore, we'll build an expression to hold on to that
    // argument pack.
    QualType TargetType = SemaRef.SubstType(NTTP->getType(), TemplateArgs,
                                            E->getLocation(),
                                            NTTP->getDeclName());
    if (TargetType.isNull())
      return ExprError();

    QualType ExprType = TargetType.getNonLValueExprType(SemaRef.Context);
    if (TargetType->isRecordType())
      ExprType.addConst();

    return new (SemaRef.Context) SubstNonTypeTemplateParmPackExpr(
        ExprType, TargetType->isReferenceType() ? VK_LValue : VK_PRValue,
        NTTP, E->getLocation(), Arg);
  }

  Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
}

return transformNonTypeTemplateParmRef(NTTP, E->getLocation(), Arg);
1486}

1488const LoopHintAttr *
1489TemplateInstantiator::TransformLoopHintAttr(const LoopHintAttr *LH) {
Expr *TransformedExpr = getDerived().TransformExpr(LH->getValue()).get();

if (TransformedExpr == LH->getValue())
  return LH;

// Generate error if there is a problem with the value.
if (getSema().CheckLoopHintExpr(TransformedExpr, LH->getLocation()))
  return LH;

// Create new LoopHintValueAttr with integral expression in place of the
// non-type template parameter.
return LoopHintAttr::CreateImplicit(getSema().Context, LH->getOption(),
                                    LH->getState(), TransformedExpr, *LH);
1503}

1505ExprResult TemplateInstantiator::transformNonTypeTemplateParmRef(
                                               NonTypeTemplateParmDecl *parm,
                                               SourceLocation loc,
                                               TemplateArgument arg) {
ExprResult result;

// Determine the substituted parameter type. We can usually infer this from
// the template argument, but not always.
auto SubstParamType = [&] {
  QualType T;
  if (parm->isExpandedParameterPack())
    T = parm->getExpansionType(SemaRef.ArgumentPackSubstitutionIndex);
  else
    T = parm->getType();
  if (parm->isParameterPack() && isa<PackExpansionType>(T))
    T = cast<PackExpansionType>(T)->getPattern();
  return SemaRef.SubstType(T, TemplateArgs, loc, parm->getDeclName());
};

bool refParam = false;

// The template argument itself might be an expression, in which case we just
// return that expression. This happens when substituting into an alias
// template.
if (arg.getKind() == TemplateArgument::Expression) {
  Expr *argExpr = arg.getAsExpr();
  result = argExpr;
  if (argExpr->isLValue()) {
    if (argExpr->getType()->isRecordType()) {
      // Check whether the parameter was actually a reference.
      QualType paramType = SubstParamType();
      if (paramType.isNull())
        return ExprError();
      refParam = paramType->isReferenceType();
    } else {
      refParam = true;
    }
  }
} else if (arg.getKind() == TemplateArgument::Declaration ||
           arg.getKind() == TemplateArgument::NullPtr) {
  ValueDecl *VD;
  if (arg.getKind() == TemplateArgument::Declaration) {
    VD = arg.getAsDecl();

    // Find the instantiation of the template argument.  This is
    // required for nested templates.
    VD = cast_or_null<ValueDecl>(
           getSema().FindInstantiatedDecl(loc, VD, TemplateArgs));
    if (!VD)
      return ExprError();
  } else {
    // Propagate NULL template argument.
    VD = nullptr;
  }

  QualType paramType = VD ? arg.getParamTypeForDecl() : arg.getNullPtrType();
  assert(!paramType.isNull() && "type substitution failed for param type")((void)0);
  assert(!paramType->isDependentType() && "param type still dependent")((void)0);
  result = SemaRef.BuildExpressionFromDeclTemplateArgument(arg, paramType, loc);
  refParam = paramType->isReferenceType();
} else {
  result = SemaRef.BuildExpressionFromIntegralTemplateArgument(arg, loc);
  assert(result.isInvalid() ||((void)0)
         SemaRef.Context.hasSameType(result.get()->getType(),((void)0)
                                     arg.getIntegralType()))((void)0);
}

if (result.isInvalid())
  return ExprError();

Expr *resultExpr = result.get();
return new (SemaRef.Context) SubstNonTypeTemplateParmExpr(
    resultExpr->getType(), resultExpr->getValueKind(), loc, parm, refParam,
    resultExpr);
1579}

1581ExprResult
1582TemplateInstantiator::TransformSubstNonTypeTemplateParmPackExpr(
                                        SubstNonTypeTemplateParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex == -1) {
  // We aren't expanding the parameter pack, so just return ourselves.
  return E;
}

TemplateArgument Arg = E->getArgumentPack();
Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
return transformNonTypeTemplateParmRef(E->getParameterPack(),
                                       E->getParameterPackLocation(),
                                       Arg);
1594}

1596ExprResult
1597TemplateInstantiator::TransformSubstNonTypeTemplateParmExpr(
                                        SubstNonTypeTemplateParmExpr *E) {
ExprResult SubstReplacement = E->getReplacement();
if (!isa<ConstantExpr>(SubstReplacement.get()))
  SubstReplacement = TransformExpr(E->getReplacement());
if (SubstReplacement.isInvalid())
  return true;
QualType SubstType = TransformType(E->getParameterType(getSema().Context));
if (SubstType.isNull())
  return true;
// The type may have been previously dependent and not now, which means we
// might have to implicit cast the argument to the new type, for example:
// template<auto T, decltype(T) U>
// concept C = sizeof(U) == 4;
// void foo() requires C<2, 'a'> { }
// When normalizing foo(), we first form the normalized constraints of C:
// AtomicExpr(sizeof(U) == 4,
//            U=SubstNonTypeTemplateParmExpr(Param=U,
//                                           Expr=DeclRef(U),
//                                           Type=decltype(T)))
// Then we substitute T = 2, U = 'a' into the parameter mapping, and need to
// produce:
// AtomicExpr(sizeof(U) == 4,
//            U=SubstNonTypeTemplateParmExpr(Param=U,
//                                           Expr=ImpCast(
//                                               decltype(2),
//                                               SubstNTTPE(Param=U, Expr='a',
//                                                          Type=char)),
//                                           Type=decltype(2)))
// The call to CheckTemplateArgument here produces the ImpCast.
TemplateArgument Converted;
if (SemaRef.CheckTemplateArgument(E->getParameter(), SubstType,
                                  SubstReplacement.get(),
                                  Converted).isInvalid())
  return true;
return transformNonTypeTemplateParmRef(E->getParameter(),
                                       E->getExprLoc(), Converted);
1634}

1636ExprResult TemplateInstantiator::RebuildVarDeclRefExpr(VarDecl *PD,
                                                     SourceLocation Loc) {
DeclarationNameInfo NameInfo(PD->getDeclName(), Loc);
return getSema().BuildDeclarationNameExpr(CXXScopeSpec(), NameInfo, PD);
1640}

1642ExprResult
1643TemplateInstantiator::TransformFunctionParmPackExpr(FunctionParmPackExpr *E) {
if (getSema().ArgumentPackSubstitutionIndex != -1) {
  // We can expand this parameter pack now.
  VarDecl *D = E->getExpansion(getSema().ArgumentPackSubstitutionIndex);
  VarDecl *VD = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), D));
  if (!VD)
    return ExprError();
  return RebuildVarDeclRefExpr(VD, E->getExprLoc());
}

QualType T = TransformType(E->getType());
if (T.isNull())
  return ExprError();

// Transform each of the parameter expansions into the corresponding
// parameters in the instantiation of the function decl.
SmallVector<VarDecl *, 8> Vars;
Vars.reserve(E->getNumExpansions());
for (FunctionParmPackExpr::iterator I = E->begin(), End = E->end();
     I != End; ++I) {
  VarDecl *D = cast_or_null<VarDecl>(TransformDecl(E->getExprLoc(), *I));
  if (!D)
    return ExprError();
  Vars.push_back(D);
}

auto *PackExpr =
    FunctionParmPackExpr::Create(getSema().Context, T, E->getParameterPack(),
                                 E->getParameterPackLocation(), Vars);
getSema().MarkFunctionParmPackReferenced(PackExpr);
return PackExpr;
1674}

1676ExprResult
1677TemplateInstantiator::TransformFunctionParmPackRefExpr(DeclRefExpr *E,
                                                     VarDecl *PD) {
typedef LocalInstantiationScope::DeclArgumentPack DeclArgumentPack;
llvm::PointerUnion<Decl *, DeclArgumentPack *> *Found
  = getSema().CurrentInstantiationScope->findInstantiationOf(PD);
assert(Found && "no instantiation for parameter pack")((void)0);

Decl *TransformedDecl;
if (DeclArgumentPack *Pack = Found->dyn_cast<DeclArgumentPack *>()) {
  // If this is a reference to a function parameter pack which we can
  // substitute but can't yet expand, build a FunctionParmPackExpr for it.
  if (getSema().ArgumentPackSubstitutionIndex == -1) {
    QualType T = TransformType(E->getType());
    if (T.isNull())
      return ExprError();
    auto *PackExpr = FunctionParmPackExpr::Create(getSema().Context, T, PD,
                                                  E->getExprLoc(), *Pack);
    getSema().MarkFunctionParmPackReferenced(PackExpr);
    return PackExpr;
  }

  TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex];
} else {
  TransformedDecl = Found->get<Decl*>();
}

// We have either an unexpanded pack or a specific expansion.
return RebuildVarDeclRefExpr(cast<VarDecl>(TransformedDecl), E->getExprLoc());
1705}

1707ExprResult
1708TemplateInstantiator::TransformDeclRefExpr(DeclRefExpr *E) {
NamedDecl *D = E->getDecl();

// Handle references to non-type template parameters and non-type template
// parameter packs.
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
  if (NTTP->getDepth() < TemplateArgs.getNumLevels())
    return TransformTemplateParmRefExpr(E, NTTP);

  // We have a non-type template parameter that isn't fully substituted;
  // FindInstantiatedDecl will find it in the local instantiation scope.
}

// Handle references to function parameter packs.
if (VarDecl *PD = dyn_cast<VarDecl>(D))
  if (PD->isParameterPack())
    return TransformFunctionParmPackRefExpr(E, PD);

return TreeTransform<TemplateInstantiator>::TransformDeclRefExpr(E);
1727}

1729ExprResult TemplateInstantiator::TransformCXXDefaultArgExpr(
  CXXDefaultArgExpr *E) {
assert(!cast<FunctionDecl>(E->getParam()->getDeclContext())->((void)0)
           getDescribedFunctionTemplate() &&((void)0)
       "Default arg expressions are never formed in dependent cases.")((void)0);
return SemaRef.BuildCXXDefaultArgExpr(E->getUsedLocation(),
                         cast<FunctionDecl>(E->getParam()->getDeclContext()),
                                      E->getParam());
1737}

1739template<typename Fn>
1740QualType TemplateInstantiator::TransformFunctionProtoType(TypeLocBuilder &TLB,
                               FunctionProtoTypeLoc TL,
                               CXXRecordDecl *ThisContext,
                               Qualifiers ThisTypeQuals,
                               Fn TransformExceptionSpec) {
// We need a local instantiation scope for this function prototype.
LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
return inherited::TransformFunctionProtoType(
    TLB, TL, ThisContext, ThisTypeQuals, TransformExceptionSpec);
1749}

1751ParmVarDecl *
1752TemplateInstantiator::TransformFunctionTypeParam(ParmVarDecl *OldParm,
                                               int indexAdjustment,
                                             Optional<unsigned> NumExpansions,
                                               bool ExpectParameterPack) {
auto NewParm =
    SemaRef.SubstParmVarDecl(OldParm, TemplateArgs, indexAdjustment,
                             NumExpansions, ExpectParameterPack);
if (NewParm && SemaRef.getLangOpts().OpenCL)
  SemaRef.deduceOpenCLAddressSpace(NewParm);
return NewParm;
1762}

1764QualType
1765TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
                                              TemplateTypeParmTypeLoc TL) {
const TemplateTypeParmType *T = TL.getTypePtr();
if (T->getDepth() < TemplateArgs.getNumLevels()) {
  // Replace the template type parameter with its corresponding
  // template argument.

  // If the corresponding template argument is NULL or doesn't exist, it's
  // because we are performing instantiation from explicitly-specified
  // template arguments in a function template class, but there were some
  // arguments left unspecified.
  if (!TemplateArgs.hasTemplateArgument(T->getDepth(), T->getIndex())) {
    TemplateTypeParmTypeLoc NewTL
      = TLB.push<TemplateTypeParmTypeLoc>(TL.getType());
    NewTL.setNameLoc(TL.getNameLoc());
    return TL.getType();
  }

  TemplateArgument Arg = TemplateArgs(T->getDepth(), T->getIndex());

  if (TemplateArgs.isRewrite()) {
    // We're rewriting the template parameter as a reference to another
    // template parameter.
    if (Arg.getKind() == TemplateArgument::Pack) {
      assert(Arg.pack_size() == 1 && Arg.pack_begin()->isPackExpansion() &&((void)0)
             "unexpected pack arguments in template rewrite")((void)0);
      Arg = Arg.pack_begin()->getPackExpansionPattern();
    }
    assert(Arg.getKind() == TemplateArgument::Type &&((void)0)
           "unexpected nontype template argument kind in template rewrite")((void)0);
    QualType NewT = Arg.getAsType();
    assert(isa<TemplateTypeParmType>(NewT) &&((void)0)
           "type parm not rewritten to type parm")((void)0);
    auto NewTL = TLB.push<TemplateTypeParmTypeLoc>(NewT);
    NewTL.setNameLoc(TL.getNameLoc());
    return NewT;
  }

  if (T->isParameterPack()) {
    assert(Arg.getKind() == TemplateArgument::Pack &&((void)0)
           "Missing argument pack")((void)0);

    if (getSema().ArgumentPackSubstitutionIndex == -1) {
      // We have the template argument pack, but we're not expanding the
      // enclosing pack expansion yet. Just save the template argument
      // pack for later substitution.
      QualType Result
        = getSema().Context.getSubstTemplateTypeParmPackType(T, Arg);
      SubstTemplateTypeParmPackTypeLoc NewTL
        = TLB.push<SubstTemplateTypeParmPackTypeLoc>(Result);
      NewTL.setNameLoc(TL.getNameLoc());
      return Result;
    }

    Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
  }

  assert(Arg.getKind() == TemplateArgument::Type &&((void)0)
         "Template argument kind mismatch")((void)0);

  QualType Replacement = Arg.getAsType();

  // TODO: only do this uniquing once, at the start of instantiation.
  QualType Result
    = getSema().Context.getSubstTemplateTypeParmType(T, Replacement);
  SubstTemplateTypeParmTypeLoc NewTL
    = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
  NewTL.setNameLoc(TL.getNameLoc());
  return Result;
}

// The template type parameter comes from an inner template (e.g.,
// the template parameter list of a member template inside the
// template we are instantiating). Create a new template type
// parameter with the template "level" reduced by one.
TemplateTypeParmDecl *NewTTPDecl = nullptr;
if (TemplateTypeParmDecl *OldTTPDecl = T->getDecl())
  NewTTPDecl = cast_or_null<TemplateTypeParmDecl>(
                                TransformDecl(TL.getNameLoc(), OldTTPDecl));

QualType Result = getSema().Context.getTemplateTypeParmType(
    T->getDepth() - TemplateArgs.getNumSubstitutedLevels(), T->getIndex(),
    T->isParameterPack(), NewTTPDecl);
TemplateTypeParmTypeLoc NewTL = TLB.push<TemplateTypeParmTypeLoc>(Result);
NewTL.setNameLoc(TL.getNameLoc());
return Result;
1851}

1853QualType
1854TemplateInstantiator::TransformSubstTemplateTypeParmPackType(
                                                          TypeLocBuilder &TLB,
                                       SubstTemplateTypeParmPackTypeLoc TL) {
if (getSema().ArgumentPackSubstitutionIndex == -1) {
  // We aren't expanding the parameter pack, so just return ourselves.
  SubstTemplateTypeParmPackTypeLoc NewTL
    = TLB.push<SubstTemplateTypeParmPackTypeLoc>(TL.getType());
  NewTL.setNameLoc(TL.getNameLoc());
  return TL.getType();
}

TemplateArgument Arg = TL.getTypePtr()->getArgumentPack();
Arg = getPackSubstitutedTemplateArgument(getSema(), Arg);
QualType Result = Arg.getAsType();

Result = getSema().Context.getSubstTemplateTypeParmType(
                                    TL.getTypePtr()->getReplacedParameter(),
                                                        Result);
SubstTemplateTypeParmTypeLoc NewTL
  = TLB.push<SubstTemplateTypeParmTypeLoc>(Result);
NewTL.setNameLoc(TL.getNameLoc());
return Result;
1876}

1878template<typename EntityPrinter>
1879static concepts::Requirement::SubstitutionDiagnostic *
1880createSubstDiag(Sema &S, TemplateDeductionInfo &Info, EntityPrinter Printer) {
SmallString<128> Message;
SourceLocation ErrorLoc;
if (Info.hasSFINAEDiagnostic()) {
  PartialDiagnosticAt PDA(SourceLocation(),
                          PartialDiagnostic::NullDiagnostic{});
  Info.takeSFINAEDiagnostic(PDA);
  PDA.second.EmitToString(S.getDiagnostics(), Message);
  ErrorLoc = PDA.first;
} else {
  ErrorLoc = Info.getLocation();
}
char *MessageBuf = new (S.Context) char[Message.size()];
std::copy(Message.begin(), Message.end(), MessageBuf);
SmallString<128> Entity;
llvm::raw_svector_ostream OS(Entity);
Printer(OS);
char *EntityBuf = new (S.Context) char[Entity.size()];
std::copy(Entity.begin(), Entity.end(), EntityBuf);
return new (S.Context) concepts::Requirement::SubstitutionDiagnostic{
    StringRef(EntityBuf, Entity.size()), ErrorLoc,
    StringRef(MessageBuf, Message.size())};
1902}

1904concepts::TypeRequirement *
1905TemplateInstantiator::TransformTypeRequirement(concepts::TypeRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;
if (Req->isSubstitutionFailure()) {
  if (AlwaysRebuild())
    return RebuildTypeRequirement(
            Req->getSubstitutionDiagnostic());
  return Req;
}

Sema::SFINAETrap Trap(SemaRef);
TemplateDeductionInfo Info(Req->getType()->getTypeLoc().getBeginLoc());
Sema::InstantiatingTemplate TypeInst(SemaRef,
    Req->getType()->getTypeLoc().getBeginLoc(), Req, Info,
    Req->getType()->getTypeLoc().getSourceRange());
if (TypeInst.isInvalid())
  return nullptr;
TypeSourceInfo *TransType = TransformType(Req->getType());
if (!TransType || Trap.hasErrorOccurred())
  return RebuildTypeRequirement(createSubstDiag(SemaRef, Info,
      [&] (llvm::raw_ostream& OS) {
          Req->getType()->getType().print(OS, SemaRef.getPrintingPolicy());
      }));
return RebuildTypeRequirement(TransType);
1929}

1931concepts::ExprRequirement *
1932TemplateInstantiator::TransformExprRequirement(concepts::ExprRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;

Sema::SFINAETrap Trap(SemaRef);

llvm::PointerUnion<Expr *, concepts::Requirement::SubstitutionDiagnostic *>
    TransExpr;
if (Req->isExprSubstitutionFailure())
  TransExpr = Req->getExprSubstitutionDiagnostic();
else {
  Expr *E = Req->getExpr();
  TemplateDeductionInfo Info(E->getBeginLoc());
  Sema::InstantiatingTemplate ExprInst(SemaRef, E->getBeginLoc(), Req, Info,
                                       E->getSourceRange());
  if (ExprInst.isInvalid())
    return nullptr;
  ExprResult TransExprRes = TransformExpr(E);
  if (TransExprRes.isInvalid() || Trap.hasErrorOccurred())
    TransExpr = createSubstDiag(SemaRef, Info, [&](llvm::raw_ostream &OS) {
      E->printPretty(OS, nullptr, SemaRef.getPrintingPolicy());
    });
  else
    TransExpr = TransExprRes.get();
}

llvm::Optional<concepts::ExprRequirement::ReturnTypeRequirement> TransRetReq;
const auto &RetReq = Req->getReturnTypeRequirement();
if (RetReq.isEmpty())
  TransRetReq.emplace();
else if (RetReq.isSubstitutionFailure())
  TransRetReq.emplace(RetReq.getSubstitutionDiagnostic());
else if (RetReq.isTypeConstraint()) {
  TemplateParameterList *OrigTPL =
      RetReq.getTypeConstraintTemplateParameterList();
  TemplateDeductionInfo Info(OrigTPL->getTemplateLoc());
  Sema::InstantiatingTemplate TPLInst(SemaRef, OrigTPL->getTemplateLoc(),
                                      Req, Info, OrigTPL->getSourceRange());
  if (TPLInst.isInvalid())
    return nullptr;
  TemplateParameterList *TPL =
      TransformTemplateParameterList(OrigTPL);
  if (!TPL)
    TransRetReq.emplace(createSubstDiag(SemaRef, Info,
        [&] (llvm::raw_ostream& OS) {
            RetReq.getTypeConstraint()->getImmediatelyDeclaredConstraint()
                ->printPretty(OS, nullptr, SemaRef.getPrintingPolicy());
        }));
  else {
    TPLInst.Clear();
    TransRetReq.emplace(TPL);
  }
}
assert(TransRetReq.hasValue() &&((void)0)
       "All code paths leading here must set TransRetReq")((void)0);
if (Expr *E = TransExpr.dyn_cast<Expr *>())
  return RebuildExprRequirement(E, Req->isSimple(), Req->getNoexceptLoc(),
                                std::move(*TransRetReq));
return RebuildExprRequirement(
    TransExpr.get<concepts::Requirement::SubstitutionDiagnostic *>(),
    Req->isSimple(), Req->getNoexceptLoc(), std::move(*TransRetReq));
1993}

1995concepts::NestedRequirement *
1996TemplateInstantiator::TransformNestedRequirement(
  concepts::NestedRequirement *Req) {
if (!Req->isDependent() && !AlwaysRebuild())
  return Req;
if (Req->isSubstitutionFailure()) {
  if (AlwaysRebuild())
    return RebuildNestedRequirement(
        Req->getSubstitutionDiagnostic());
  return Req;
}
Sema::InstantiatingTemplate ReqInst(SemaRef,
    Req->getConstraintExpr()->getBeginLoc(), Req,
    Sema::InstantiatingTemplate::ConstraintsCheck{},
    Req->getConstraintExpr()->getSourceRange());

ExprResult TransConstraint;
TemplateDeductionInfo Info(Req->getConstraintExpr()->getBeginLoc());
{
  EnterExpressionEvaluationContext ContextRAII(
      SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
  Sema::SFINAETrap Trap(SemaRef);
  Sema::InstantiatingTemplate ConstrInst(SemaRef,
      Req->getConstraintExpr()->getBeginLoc(), Req, Info,
      Req->getConstraintExpr()->getSourceRange());
  if (ConstrInst.isInvalid())
    return nullptr;
  TransConstraint = TransformExpr(Req->getConstraintExpr());
  if (TransConstraint.isInvalid() || Trap.hasErrorOccurred())
    return RebuildNestedRequirement(createSubstDiag(SemaRef, Info,
        [&] (llvm::raw_ostream& OS) {
            Req->getConstraintExpr()->printPretty(OS, nullptr,
                                                  SemaRef.getPrintingPolicy());
        }));
}
return RebuildNestedRequirement(TransConstraint.get());
2031}


2034/// Perform substitution on the type T with a given set of template
2035/// arguments.
2036///
2037/// This routine substitutes the given template arguments into the
2038/// type T and produces the instantiated type.
2039///
2040/// \param T the type into which the template arguments will be
2041/// substituted. If this type is not dependent, it will be returned
2042/// immediately.
2043///
2044/// \param Args the template arguments that will be
2045/// substituted for the top-level template parameters within T.
2046///
2047/// \param Loc the location in the source code where this substitution
2048/// is being performed. It will typically be the location of the
2049/// declarator (if we're instantiating the type of some declaration)
2050/// or the location of the type in the source code (if, e.g., we're
2051/// instantiating the type of a cast expression).
2052///
2053/// \param Entity the name of the entity associated with a declaration
2054/// being instantiated (if any). May be empty to indicate that there
2055/// is no such entity (if, e.g., this is a type that occurs as part of
2056/// a cast expression) or that the entity has no name (e.g., an
2057/// unnamed function parameter).
2058///
2059/// \param AllowDeducedTST Whether a DeducedTemplateSpecializationType is
2060/// acceptable as the top level type of the result.
2061///
2062/// \returns If the instantiation succeeds, the instantiated
2063/// type. Otherwise, produces diagnostics and returns a NULL type.
2064TypeSourceInfo *Sema::SubstType(TypeSourceInfo *T,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity,
                              bool AllowDeducedTST) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

if (!T->getType()->isInstantiationDependentType() &&
    !T->getType()->isVariablyModifiedType())
  return T;

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
return AllowDeducedTST ? Instantiator.TransformTypeWithDeducedTST(T)
                       : Instantiator.TransformType(T);
2080}

2082TypeSourceInfo *Sema::SubstType(TypeLoc TL,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

if (TL.getType().isNull())
  return nullptr;

if (!TL.getType()->isInstantiationDependentType() &&
    !TL.getType()->isVariablyModifiedType()) {
  // FIXME: Make a copy of the TypeLoc data here, so that we can
  // return a new TypeSourceInfo. Inefficient!
  TypeLocBuilder TLB;
  TLB.pushFullCopy(TL);
  return TLB.getTypeSourceInfo(Context, TL.getType());
}

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);
TypeLocBuilder TLB;
TLB.reserve(TL.getFullDataSize());
QualType Result = Instantiator.TransformType(TLB, TL);
if (Result.isNull())
  return nullptr;

return TLB.getTypeSourceInfo(Context, Result);
2110}

2112/// Deprecated form of the above.
2113QualType Sema::SubstType(QualType T,
                       const MultiLevelTemplateArgumentList &TemplateArgs,
                       SourceLocation Loc, DeclarationName Entity) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

// If T is not a dependent type or a variably-modified type, there
// is nothing to do.
if (!T->isInstantiationDependentType() && !T->isVariablyModifiedType())
  return T;

TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, Entity);
return Instantiator.TransformType(T);
2127}

2129static bool NeedsInstantiationAsFunctionType(TypeSourceInfo *T) {
if (T->getType()->isInstantiationDependentType() ||
    T->getType()->isVariablyModifiedType())
  return true;

TypeLoc TL = T->getTypeLoc().IgnoreParens();
if (!TL.getAs<FunctionProtoTypeLoc>())
  return false;

FunctionProtoTypeLoc FP = TL.castAs<FunctionProtoTypeLoc>();
for (ParmVarDecl *P : FP.getParams()) {
  // This must be synthesized from a typedef.
  if (!P) continue;

  // If there are any parameters, a new TypeSourceInfo that refers to the
  // instantiated parameters must be built.
  return true;
}

return false;
2149}

2151/// A form of SubstType intended specifically for instantiating the
2152/// type of a FunctionDecl.  Its purpose is solely to force the
2153/// instantiation of default-argument expressions and to avoid
2154/// instantiating an exception-specification.
2155TypeSourceInfo *Sema::SubstFunctionDeclType(TypeSourceInfo *T,
                              const MultiLevelTemplateArgumentList &Args,
                              SourceLocation Loc,
                              DeclarationName Entity,
                              CXXRecordDecl *ThisContext,
                              Qualifiers ThisTypeQuals) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

if (!NeedsInstantiationAsFunctionType(T))
  return T;

TemplateInstantiator Instantiator(*this, Args, Loc, Entity);

TypeLocBuilder TLB;

TypeLoc TL = T->getTypeLoc();
TLB.reserve(TL.getFullDataSize());

QualType Result;

if (FunctionProtoTypeLoc Proto =
        TL.IgnoreParens().getAs<FunctionProtoTypeLoc>()) {
  // Instantiate the type, other than its exception specification. The
  // exception specification is instantiated in InitFunctionInstantiation
  // once we've built the FunctionDecl.
  // FIXME: Set the exception specification to EST_Uninstantiated here,
  // instead of rebuilding the function type again later.
  Result = Instantiator.TransformFunctionProtoType(
      TLB, Proto, ThisContext, ThisTypeQuals,
      [](FunctionProtoType::ExceptionSpecInfo &ESI,
         bool &Changed) { return false; });
} else {
  Result = Instantiator.TransformType(TLB, TL);
}
if (Result.isNull())
  return nullptr;

return TLB.getTypeSourceInfo(Context, Result);
2195}

2197bool Sema::SubstExceptionSpec(SourceLocation Loc,
                            FunctionProtoType::ExceptionSpecInfo &ESI,
                            SmallVectorImpl<QualType> &ExceptionStorage,
                            const MultiLevelTemplateArgumentList &Args) {
assert(ESI.Type != EST_Uninstantiated)((void)0);

bool Changed = false;
TemplateInstantiator Instantiator(*this, Args, Loc, DeclarationName());
return Instantiator.TransformExceptionSpec(Loc, ESI, ExceptionStorage,
                                           Changed);
2207}

2209void Sema::SubstExceptionSpec(FunctionDecl *New, const FunctionProtoType *Proto,
                            const MultiLevelTemplateArgumentList &Args) {
FunctionProtoType::ExceptionSpecInfo ESI =
    Proto->getExtProtoInfo().ExceptionSpec;

SmallVector<QualType, 4> ExceptionStorage;
if (SubstExceptionSpec(New->getTypeSourceInfo()->getTypeLoc().getEndLoc(),
                       ESI, ExceptionStorage, Args))
  // On error, recover by dropping the exception specification.
  ESI.Type = EST_None;

UpdateExceptionSpec(New, ESI);
2221}

2223namespace {

struct GetContainedInventedTypeParmVisitor :
  public TypeVisitor<GetContainedInventedTypeParmVisitor,
                     TemplateTypeParmDecl *> {
  using TypeVisitor<GetContainedInventedTypeParmVisitor,
                    TemplateTypeParmDecl *>::Visit;

  TemplateTypeParmDecl *Visit(QualType T) {
    if (T.isNull())
      return nullptr;
    return Visit(T.getTypePtr());
  }
  // The deduced type itself.
  TemplateTypeParmDecl *VisitTemplateTypeParmType(
      const TemplateTypeParmType *T) {
    if (!T->getDecl() || !T->getDecl()->isImplicit())
      return nullptr;
    return T->getDecl();
  }

  // Only these types can contain 'auto' types, and subsequently be replaced
  // by references to invented parameters.

  TemplateTypeParmDecl *VisitElaboratedType(const ElaboratedType *T) {
    return Visit(T->getNamedType());
  }

  TemplateTypeParmDecl *VisitPointerType(const PointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitBlockPointerType(const BlockPointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitReferenceType(const ReferenceType *T) {
    return Visit(T->getPointeeTypeAsWritten());
  }

  TemplateTypeParmDecl *VisitMemberPointerType(const MemberPointerType *T) {
    return Visit(T->getPointeeType());
  }

  TemplateTypeParmDecl *VisitArrayType(const ArrayType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitDependentSizedExtVectorType(
    const DependentSizedExtVectorType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitVectorType(const VectorType *T) {
    return Visit(T->getElementType());
  }

  TemplateTypeParmDecl *VisitFunctionProtoType(const FunctionProtoType *T) {
    return VisitFunctionType(T);
  }

  TemplateTypeParmDecl *VisitFunctionType(const FunctionType *T) {
    return Visit(T->getReturnType());
  }

  TemplateTypeParmDecl *VisitParenType(const ParenType *T) {
    return Visit(T->getInnerType());
  }

  TemplateTypeParmDecl *VisitAttributedType(const AttributedType *T) {
    return Visit(T->getModifiedType());
  }

  TemplateTypeParmDecl *VisitMacroQualifiedType(const MacroQualifiedType *T) {
    return Visit(T->getUnderlyingType());
  }

  TemplateTypeParmDecl *VisitAdjustedType(const AdjustedType *T) {
    return Visit(T->getOriginalType());
  }

  TemplateTypeParmDecl *VisitPackExpansionType(const PackExpansionType *T) {
    return Visit(T->getPattern());
  }
};

2309} // namespace

2311ParmVarDecl *Sema::SubstParmVarDecl(ParmVarDecl *OldParm,
                          const MultiLevelTemplateArgumentList &TemplateArgs,
                                  int indexAdjustment,
                                  Optional<unsigned> NumExpansions,
                                  bool ExpectParameterPack) {
TypeSourceInfo *OldDI = OldParm->getTypeSourceInfo();
TypeSourceInfo *NewDI = nullptr;

TypeLoc OldTL = OldDI->getTypeLoc();
if (PackExpansionTypeLoc ExpansionTL = OldTL.getAs<PackExpansionTypeLoc>()) {

  // We have a function parameter pack. Substitute into the pattern of the
  // expansion.
  NewDI = SubstType(ExpansionTL.getPatternLoc(), TemplateArgs,
                    OldParm->getLocation(), OldParm->getDeclName());
  if (!NewDI)
    return nullptr;

  if (NewDI->getType()->containsUnexpandedParameterPack()) {
    // We still have unexpanded parameter packs, which means that
    // our function parameter is still a function parameter pack.
    // Therefore, make its type a pack expansion type.
    NewDI = CheckPackExpansion(NewDI, ExpansionTL.getEllipsisLoc(),
                               NumExpansions);
  } else if (ExpectParameterPack) {
    // We expected to get a parameter pack but didn't (because the type
    // itself is not a pack expansion type), so complain. This can occur when
    // the substitution goes through an alias template that "loses" the
    // pack expansion.
    Diag(OldParm->getLocation(),
         diag::err_function_parameter_pack_without_parameter_packs)
      << NewDI->getType();
    return nullptr;
  }
} else {
  NewDI = SubstType(OldDI, TemplateArgs, OldParm->getLocation(),
                    OldParm->getDeclName());
}

if (!NewDI)
  return nullptr;

if (NewDI->getType()->isVoidType()) {
  Diag(OldParm->getLocation(), diag::err_param_with_void_type);
  return nullptr;
}

// In abbreviated templates, TemplateTypeParmDecls with possible
// TypeConstraints are created when the parameter list is originally parsed.
// The TypeConstraints can therefore reference other functions parameters in
// the abbreviated function template, which is why we must instantiate them
// here, when the instantiated versions of those referenced parameters are in
// scope.
if (TemplateTypeParmDecl *TTP =
        GetContainedInventedTypeParmVisitor().Visit(OldDI->getType())) {
  if (const TypeConstraint *TC = TTP->getTypeConstraint()) {
    auto *Inst = cast_or_null<TemplateTypeParmDecl>(
        FindInstantiatedDecl(TTP->getLocation(), TTP, TemplateArgs));
    // We will first get here when instantiating the abbreviated function
    // template's described function, but we might also get here later.
    // Make sure we do not instantiate the TypeConstraint more than once.
    if (Inst && !Inst->getTypeConstraint()) {
      // TODO: Concepts: do not instantiate the constraint (delayed constraint
      // substitution)
      const ASTTemplateArgumentListInfo *TemplArgInfo
        = TC->getTemplateArgsAsWritten();
      TemplateArgumentListInfo InstArgs;

      if (TemplArgInfo) {
        InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
        InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
        if (Subst(TemplArgInfo->getTemplateArgs(),
                  TemplArgInfo->NumTemplateArgs, InstArgs, TemplateArgs))
          return nullptr;
      }
      if (AttachTypeConstraint(
              TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
              TC->getNamedConcept(), TemplArgInfo ? &InstArgs : nullptr, Inst,
              TTP->isParameterPack()
                  ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
                        ->getEllipsisLoc()
                  : SourceLocation()))
        return nullptr;
    }
  }
}

ParmVarDecl *NewParm = CheckParameter(Context.getTranslationUnitDecl(),
                                      OldParm->getInnerLocStart(),
                                      OldParm->getLocation(),
                                      OldParm->getIdentifier(),
                                      NewDI->getType(), NewDI,
                                      OldParm->getStorageClass());
if (!NewParm)
  return nullptr;

// Mark the (new) default argument as uninstantiated (if any).
if (OldParm->hasUninstantiatedDefaultArg()) {
  Expr *Arg = OldParm->getUninstantiatedDefaultArg();
  NewParm->setUninstantiatedDefaultArg(Arg);
} else if (OldParm->hasUnparsedDefaultArg()) {
  NewParm->setUnparsedDefaultArg();
  UnparsedDefaultArgInstantiations[OldParm].push_back(NewParm);
} else if (Expr *Arg = OldParm->getDefaultArg()) {
  FunctionDecl *OwningFunc = cast<FunctionDecl>(OldParm->getDeclContext());
  if (OwningFunc->isInLocalScopeForInstantiation()) {
    // Instantiate default arguments for methods of local classes (DR1484)
    // and non-defining declarations.
    Sema::ContextRAII SavedContext(*this, OwningFunc);
    LocalInstantiationScope Local(*this, true);
    ExprResult NewArg = SubstExpr(Arg, TemplateArgs);
    if (NewArg.isUsable()) {
      // It would be nice if we still had this.
      SourceLocation EqualLoc = NewArg.get()->getBeginLoc();
      ExprResult Result =
          ConvertParamDefaultArgument(NewParm, NewArg.get(), EqualLoc);
      if (Result.isInvalid())
        return nullptr;

      SetParamDefaultArgument(NewParm, Result.getAs<Expr>(), EqualLoc);
    }
  } else {
    // FIXME: if we non-lazily instantiated non-dependent default args for
    // non-dependent parameter types we could remove a bunch of duplicate
    // conversion warnings for such arguments.
    NewParm->setUninstantiatedDefaultArg(Arg);
  }
}

NewParm->setHasInheritedDefaultArg(OldParm->hasInheritedDefaultArg());

if (OldParm->isParameterPack() && !NewParm->isParameterPack()) {
  // Add the new parameter to the instantiated parameter pack.
  CurrentInstantiationScope->InstantiatedLocalPackArg(OldParm, NewParm);
} else {
  // Introduce an Old -> New mapping
  CurrentInstantiationScope->InstantiatedLocal(OldParm, NewParm);
}

// FIXME: OldParm may come from a FunctionProtoType, in which case CurContext
// can be anything, is this right ?
NewParm->setDeclContext(CurContext);

NewParm->setScopeInfo(OldParm->getFunctionScopeDepth(),
                      OldParm->getFunctionScopeIndex() + indexAdjustment);

InstantiateAttrs(TemplateArgs, OldParm, NewParm);

return NewParm;
2460}

2462/// Substitute the given template arguments into the given set of
2463/// parameters, producing the set of parameter types that would be generated
2464/// from such a substitution.
2465bool Sema::SubstParmTypes(
  SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
  const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
  const MultiLevelTemplateArgumentList &TemplateArgs,
  SmallVectorImpl<QualType> &ParamTypes,
  SmallVectorImpl<ParmVarDecl *> *OutParams,
  ExtParameterInfoBuilder &ParamInfos) {
assert(!CodeSynthesisContexts.empty() &&((void)0)
       "Cannot perform an instantiation without some context on the "((void)0)
       "instantiation stack")((void)0);

TemplateInstantiator Instantiator(*this, TemplateArgs, Loc,
                                  DeclarationName());
return Instantiator.TransformFunctionTypeParams(
    Loc, Params, nullptr, ExtParamInfos, ParamTypes, OutParams, ParamInfos);
2480}

2482/// Perform substitution on the base class specifiers of the
2483/// given class template specialization.
2484///
2485/// Produces a diagnostic and returns true on error, returns false and
2486/// attaches the instantiated base classes to the class template
2487/// specialization if successful.
2488bool
2489Sema::SubstBaseSpecifiers(CXXRecordDecl *Instantiation,
                        CXXRecordDecl *Pattern,
                        const MultiLevelTemplateArgumentList &TemplateArgs) {
bool Invalid = false;
SmallVector<CXXBaseSpecifier*, 4> InstantiatedBases;
for (const auto &Base : Pattern->bases()) {
  if (!Base.getType()->isDependentType()) {
    if (const CXXRecordDecl *RD = Base.getType()->getAsCXXRecordDecl()) {
      if (RD->isInvalidDecl())
        Instantiation->setInvalidDecl();
    }
    InstantiatedBases.push_back(new (Context) CXXBaseSpecifier(Base));
    continue;
  }

  SourceLocation EllipsisLoc;
  TypeSourceInfo *BaseTypeLoc;
  if (Base.isPackExpansion()) {
    // This is a pack expansion. See whether we should expand it now, or
    // wait until later.
    SmallVector<UnexpandedParameterPack, 2> Unexpanded;
    collectUnexpandedParameterPacks(Base.getTypeSourceInfo()->getTypeLoc(),
                                    Unexpanded);
    bool ShouldExpand = false;
    bool RetainExpansion = false;
    Optional<unsigned> NumExpansions;
    if (CheckParameterPacksForExpansion(Base.getEllipsisLoc(),
                                        Base.getSourceRange(),
                                        Unexpanded,
                                        TemplateArgs, ShouldExpand,
                                        RetainExpansion,
                                        NumExpansions)) {
      Invalid = true;
      continue;
    }

    // If we should expand this pack expansion now, do so.
    if (ShouldExpand) {
      for (unsigned I = 0; I != *NumExpansions; ++I) {
          Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, I);

        TypeSourceInfo *BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                                                TemplateArgs,
                                            Base.getSourceRange().getBegin(),
                                                DeclarationName());
        if (!BaseTypeLoc) {
          Invalid = true;
          continue;
        }

        if (CXXBaseSpecifier *InstantiatedBase
              = CheckBaseSpecifier(Instantiation,
                                   Base.getSourceRange(),
                                   Base.isVirtual(),
                                   Base.getAccessSpecifierAsWritten(),
                                   BaseTypeLoc,
                                   SourceLocation()))
          InstantiatedBases.push_back(InstantiatedBase);
        else
          Invalid = true;
      }

      continue;
    }

    // The resulting base specifier will (still) be a pack expansion.
    EllipsisLoc = Base.getEllipsisLoc();
    Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
    BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                            TemplateArgs,
                            Base.getSourceRange().getBegin(),
                            DeclarationName());
  } else {
    BaseTypeLoc = SubstType(Base.getTypeSourceInfo(),
                            TemplateArgs,
                            Base.getSourceRange().getBegin(),
                            DeclarationName());
  }

  if (!BaseTypeLoc) {
    Invalid = true;
    continue;
  }

  if (CXXBaseSpecifier *InstantiatedBase
        = CheckBaseSpecifier(Instantiation,
                             Base.getSourceRange(),
                             Base.isVirtual(),
                             Base.getAccessSpecifierAsWritten(),
                             BaseTypeLoc,
                             EllipsisLoc))
    InstantiatedBases.push_back(InstantiatedBase);
  else
    Invalid = true;
}

if (!Invalid && AttachBaseSpecifiers(Instantiation, InstantiatedBases))
  Invalid = true;

return Invalid;
2589}

2591// Defined via #include from SemaTemplateInstantiateDecl.cpp
2592namespace clang {
namespace sema {
  Attr *instantiateTemplateAttribute(const Attr *At, ASTContext &C, Sema &S,
                          const MultiLevelTemplateArgumentList &TemplateArgs);
  Attr *instantiateTemplateAttributeForDecl(
      const Attr *At, ASTContext &C, Sema &S,
      const MultiLevelTemplateArgumentList &TemplateArgs);
}
2600}

2602/// Instantiate the definition of a class from a given pattern.
2603///
2604/// \param PointOfInstantiation The point of instantiation within the
2605/// source code.
2606///
2607/// \param Instantiation is the declaration whose definition is being
2608/// instantiated. This will be either a class template specialization
2609/// or a member class of a class template specialization.
2610///
2611/// \param Pattern is the pattern from which the instantiation
2612/// occurs. This will be either the declaration of a class template or
2613/// the declaration of a member class of a class template.
2614///
2615/// \param TemplateArgs The template arguments to be substituted into
2616/// the pattern.
2617///
2618/// \param TSK the kind of implicit or explicit instantiation to perform.
2619///
2620/// \param Complain whether to complain if the class cannot be instantiated due
2621/// to the lack of a definition.
2622///
2623/// \returns true if an error occurred, false otherwise.
2624bool
2625Sema::InstantiateClass(SourceLocation PointOfInstantiation,
                     CXXRecordDecl *Instantiation, CXXRecordDecl *Pattern,
                     const MultiLevelTemplateArgumentList &TemplateArgs,
                     TemplateSpecializationKind TSK,
                     bool Complain) {
CXXRecordDecl *PatternDef
8
←
'PatternDef' initialized to a null pointer value→
  = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
7
←
Assuming null pointer is passed into cast→
if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Instantiation,
9
←
Assuming the condition is false→
10
←
Taking false branch→
                              Instantiation->getInstantiatedFromMemberClass(),
                                   Pattern, PatternDef, TSK, Complain))
  return true;

llvm::TimeTraceScope TimeScope("InstantiateClass", [&]() {
  std::string Name;
  llvm::raw_string_ostream OS(Name);
  Instantiation->getNameForDiagnostic(OS, getPrintingPolicy(),
                                      /*Qualified=*/true);
  return Name;
});

Pattern = PatternDef;
11
←
Null pointer value stored to 'Pattern'→

// Record the point of instantiation.
if (MemberSpecializationInfo *MSInfo
12
←
Assuming 'MSInfo' is null→
13
←
Taking false branch→
      = Instantiation->getMemberSpecializationInfo()) {
  MSInfo->setTemplateSpecializationKind(TSK);
  MSInfo->setPointOfInstantiation(PointOfInstantiation);
} else if (ClassTemplateSpecializationDecl *Spec14.1
'Spec' is null

14.1	'Spec' is null

←

Taking false branch

→

2653 = dyn_cast<ClassTemplateSpecializationDecl>(Instantiation)) {

←

Assuming 'Instantiation' is not a 'ClassTemplateSpecializationDecl'

→

2654 Spec->setTemplateSpecializationKind(TSK); 2655 Spec->setPointOfInstantiation(PointOfInstantiation); 2656 } 2657 2658 InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation);

←

Calling constructor for 'InstantiatingTemplate'

→

←

Returning from constructor for 'InstantiatingTemplate'

→

2659 if (Inst.isInvalid())

←

Calling 'InstantiatingTemplate::isInvalid'

→

←

Returning from 'InstantiatingTemplate::isInvalid'

→

←

Taking false branch

→

2660 return true; 2661 assert(!Inst.isAlreadyInstantiating() && "should have been caught by caller")((void)0); 2662 PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(), 2663 "instantiating class definition"); 2664 2665 // Enter the scope of this instantiation. We don't use 2666 // PushDeclContext because we don't have a scope. 2667 ContextRAII SavedContext(*this, Instantiation); 2668 EnterExpressionEvaluationContext EvalContext( 2669 *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated); 2670 2671 // If this is an instantiation of a local class, merge this local 2672 // instantiation scope with the enclosing scope. Otherwise, every 2673 // instantiation of a class has its own local instantiation scope. 2674 bool MergeWithParentScope = !Instantiation->isDefinedOutsideFunctionOrMethod(); 2675 LocalInstantiationScope Scope(*this, MergeWithParentScope); 2676 2677 // Some class state isn't processed immediately but delayed till class 2678 // instantiation completes. We may not be ready to handle any delayed state 2679 // already on the stack as it might correspond to a different class, so save 2680 // it now and put it back later. 2681 SavePendingParsedClassStateRAII SavedPendingParsedClassState(*this); 2682 2683 // Pull attributes from the pattern onto the instantiation. 2684 InstantiateAttrs(TemplateArgs, Pattern, Instantiation); 2685 2686 // Start the definition of this instantiation. 2687 Instantiation->startDefinition(); 2688 2689 // The instantiation is visible here, even if it was first declared in an 2690 // unimported module. 2691 Instantiation->setVisibleDespiteOwningModule(); 2692 2693 // FIXME: This loses the as-written tag kind for an explicit instantiation. 2694 Instantiation->setTagKind(Pattern->getTagKind());

←

Called C++ object pointer is null

2695 2696 // Do substitution on the base class specifiers. 2697 if (SubstBaseSpecifiers(Instantiation, Pattern, TemplateArgs)) 2698 Instantiation->setInvalidDecl(); 2699 2700 TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs); 2701 SmallVector<Decl*, 4> Fields; 2702 // Delay instantiation of late parsed attributes. 2703 LateInstantiatedAttrVec LateAttrs; 2704 Instantiator.enableLateAttributeInstantiation(&LateAttrs); 2705 2706 bool MightHaveConstexprVirtualFunctions = false; 2707 for (auto *Member : Pattern->decls()) { 2708 // Don't instantiate members not belonging in this semantic context. 2709 // e.g. for: 2710 // @code 2711 // template <int i> class A { 2712 // class B *g; 2713 // }; 2714 // @endcode 2715 // 'class B' has the template as lexical context but semantically it is 2716 // introduced in namespace scope. 2717 if (Member->getDeclContext() != Pattern) 2718 continue; 2719 2720 // BlockDecls can appear in a default-member-initializer. They must be the 2721 // child of a BlockExpr, so we only know how to instantiate them from there. 2722 // Similarly, lambda closure types are recreated when instantiating the 2723 // corresponding LambdaExpr. 2724 if (isa<BlockDecl>(Member) || 2725 (isa<CXXRecordDecl>(Member) && cast<CXXRecordDecl>(Member)->isLambda())) 2726 continue; 2727 2728 if (Member->isInvalidDecl()) { 2729 Instantiation->setInvalidDecl(); 2730 continue; 2731 } 2732 2733 Decl *NewMember = Instantiator.Visit(Member); 2734 if (NewMember) { 2735 if (FieldDecl *Field = dyn_cast<FieldDecl>(NewMember)) { 2736 Fields.push_back(Field); 2737 } else if (EnumDecl *Enum = dyn_cast<EnumDecl>(NewMember)) { 2738 // C++11 [temp.inst]p1: The implicit instantiation of a class template 2739 // specialization causes the implicit instantiation of the definitions 2740 // of unscoped member enumerations. 2741 // Record a point of instantiation for this implicit instantiation. 2742 if (TSK == TSK_ImplicitInstantiation && !Enum->isScoped() && 2743 Enum->isCompleteDefinition()) { 2744 MemberSpecializationInfo *MSInfo =Enum->getMemberSpecializationInfo(); 2745 assert(MSInfo && "no spec info for member enum specialization")((void)0); 2746 MSInfo->setTemplateSpecializationKind(TSK_ImplicitInstantiation); 2747 MSInfo->setPointOfInstantiation(PointOfInstantiation); 2748 } 2749 } else if (StaticAssertDecl *SA = dyn_cast<StaticAssertDecl>(NewMember)) { 2750 if (SA->isFailed()) { 2751 // A static_assert failed. Bail out; instantiating this 2752 // class is probably not meaningful. 2753 Instantiation->setInvalidDecl(); 2754 break; 2755 } 2756 } else if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewMember)) { 2757 if (MD->isConstexpr() && !MD->getFriendObjectKind() && 2758 (MD->isVirtualAsWritten() || Instantiation->getNumBases())) 2759 MightHaveConstexprVirtualFunctions = true; 2760 } 2761 2762 if (NewMember->isInvalidDecl()) 2763 Instantiation->setInvalidDecl(); 2764 } else { 2765 // FIXME: Eventually, a NULL return will mean that one of the 2766 // instantiations was a semantic disaster, and we'll want to mark the 2767 // declaration invalid. 2768 // For now, we expect to skip some members that we can't yet handle. 2769 } 2770 } 2771 2772 // Finish checking fields. 2773 ActOnFields(nullptr, Instantiation->getLocation(), Instantiation, Fields, 2774 SourceLocation(), SourceLocation(), ParsedAttributesView()); 2775 CheckCompletedCXXClass(nullptr, Instantiation); 2776 2777 // Default arguments are parsed, if not instantiated. We can go instantiate 2778 // default arg exprs for default constructors if necessary now. Unless we're 2779 // parsing a class, in which case wait until that's finished. 2780 if (ParsingClassDepth == 0) 2781 ActOnFinishCXXNonNestedClass(); 2782 2783 // Instantiate late parsed attributes, and attach them to their decls. 2784 // See Sema::InstantiateAttrs 2785 for (LateInstantiatedAttrVec::iterator I = LateAttrs.begin(), 2786 E = LateAttrs.end(); I != E; ++I) { 2787 assert(CurrentInstantiationScope == Instantiator.getStartingScope())((void)0); 2788 CurrentInstantiationScope = I->Scope; 2789 2790 // Allow 'this' within late-parsed attributes. 2791 NamedDecl *ND = dyn_cast<NamedDecl>(I->NewDecl); 2792 CXXRecordDecl *ThisContext = 2793 dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext()); 2794 CXXThisScopeRAII ThisScope(*this, ThisContext, Qualifiers(), 2795 ND && ND->isCXXInstanceMember()); 2796 2797 Attr *NewAttr = 2798 instantiateTemplateAttribute(I->TmplAttr, Context, *this, TemplateArgs); 2799 if (NewAttr) 2800 I->NewDecl->addAttr(NewAttr); 2801 LocalInstantiationScope::deleteScopes(I->Scope, 2802 Instantiator.getStartingScope()); 2803 } 2804 Instantiator.disableLateAttributeInstantiation(); 2805 LateAttrs.clear(); 2806 2807 ActOnFinishDelayedMemberInitializers(Instantiation); 2808 2809 // FIXME: We should do something similar for explicit instantiations so they 2810 // end up in the right module. 2811 if (TSK == TSK_ImplicitInstantiation) { 2812 Instantiation->setLocation(Pattern->getLocation()); 2813 Instantiation->setLocStart(Pattern->getInnerLocStart()); 2814 Instantiation->setBraceRange(Pattern->getBraceRange()); 2815 } 2816 2817 if (!Instantiation->isInvalidDecl()) { 2818 // Perform any dependent diagnostics from the pattern. 2819 if (Pattern->isDependentContext()) 2820 PerformDependentDiagnostics(Pattern, TemplateArgs); 2821 2822 // Instantiate any out-of-line class template partial 2823 // specializations now. 2824 for (TemplateDeclInstantiator::delayed_partial_spec_iterator 2825 P = Instantiator.delayed_partial_spec_begin(), 2826 PEnd = Instantiator.delayed_partial_spec_end(); 2827 P != PEnd; ++P) { 2828 if (!Instantiator.InstantiateClassTemplatePartialSpecialization( 2829 P->first, P->second)) { 2830 Instantiation->setInvalidDecl(); 2831 break; 2832 } 2833 } 2834 2835 // Instantiate any out-of-line variable template partial 2836 // specializations now. 2837 for (TemplateDeclInstantiator::delayed_var_partial_spec_iterator 2838 P = Instantiator.delayed_var_partial_spec_begin(), 2839 PEnd = Instantiator.delayed_var_partial_spec_end(); 2840 P != PEnd; ++P) { 2841 if (!Instantiator.InstantiateVarTemplatePartialSpecialization( 2842 P->first, P->second)) { 2843 Instantiation->setInvalidDecl(); 2844 break; 2845 } 2846 } 2847 } 2848 2849 // Exit the scope of this instantiation. 2850 SavedContext.pop(); 2851 2852 if (!Instantiation->isInvalidDecl()) { 2853 // Always emit the vtable for an explicit instantiation definition 2854 // of a polymorphic class template specialization. Otherwise, eagerly 2855 // instantiate only constexpr virtual functions in preparation for their use 2856 // in constant evaluation. 2857 if (TSK == TSK_ExplicitInstantiationDefinition) 2858 MarkVTableUsed(PointOfInstantiation, Instantiation, true); 2859 else if (MightHaveConstexprVirtualFunctions) 2860 MarkVirtualMembersReferenced(PointOfInstantiation, Instantiation, 2861 /*ConstexprOnly*/ true); 2862 } 2863 2864 Consumer.HandleTagDeclDefinition(Instantiation); 2865 2866 return Instantiation->isInvalidDecl(); 2867} 2868 2869/// Instantiate the definition of an enum from a given pattern. 2870/// 2871/// \param PointOfInstantiation The point of instantiation within the 2872/// source code. 2873/// \param Instantiation is the declaration whose definition is being 2874/// instantiated. This will be a member enumeration of a class 2875/// temploid specialization, or a local enumeration within a 2876/// function temploid specialization. 2877/// \param Pattern The templated declaration from which the instantiation 2878/// occurs. 2879/// \param TemplateArgs The template arguments to be substituted into 2880/// the pattern. 2881/// \param TSK The kind of implicit or explicit instantiation to perform. 2882/// 2883/// \return \c true if an error occurred, \c false otherwise. 2884bool Sema::InstantiateEnum(SourceLocation PointOfInstantiation, 2885 EnumDecl *Instantiation, EnumDecl *Pattern, 2886 const MultiLevelTemplateArgumentList &TemplateArgs, 2887 TemplateSpecializationKind TSK) { 2888 EnumDecl *PatternDef = Pattern->getDefinition(); 2889 if (DiagnoseUninstantiableTemplate(PointOfInstantiation, Instantiation, 2890 Instantiation->getInstantiatedFromMemberEnum(), 2891 Pattern, PatternDef, TSK,/*Complain*/true)) 2892 return true; 2893 Pattern = PatternDef; 2894 2895 // Record the point of instantiation. 2896 if (MemberSpecializationInfo *MSInfo 2897 = Instantiation->getMemberSpecializationInfo()) { 2898 MSInfo->setTemplateSpecializationKind(TSK); 2899 MSInfo->setPointOfInstantiation(PointOfInstantiation); 2900 } 2901 2902 InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); 2903 if (Inst.isInvalid()) 2904 return true; 2905 if (Inst.isAlreadyInstantiating()) 2906 return false; 2907 PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(), 2908 "instantiating enum definition"); 2909 2910 // The instantiation is visible here, even if it was first declared in an 2911 // unimported module. 2912 Instantiation->setVisibleDespiteOwningModule(); 2913 2914 // Enter the scope of this instantiation. We don't use 2915 // PushDeclContext because we don't have a scope. 2916 ContextRAII SavedContext(*this, Instantiation); 2917 EnterExpressionEvaluationContext EvalContext( 2918 *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated); 2919 2920 LocalInstantiationScope Scope(*this, /*MergeWithParentScope*/true); 2921 2922 // Pull attributes from the pattern onto the instantiation. 2923 InstantiateAttrs(TemplateArgs, Pattern, Instantiation); 2924 2925 TemplateDeclInstantiator Instantiator(*this, Instantiation, TemplateArgs); 2926 Instantiator.InstantiateEnumDefinition(Instantiation, Pattern); 2927 2928 // Exit the scope of this instantiation. 2929 SavedContext.pop(); 2930 2931 return Instantiation->isInvalidDecl(); 2932} 2933 2934 2935/// Instantiate the definition of a field from the given pattern. 2936/// 2937/// \param PointOfInstantiation The point of instantiation within the 2938/// source code. 2939/// \param Instantiation is the declaration whose definition is being 2940/// instantiated. This will be a class of a class temploid 2941/// specialization, or a local enumeration within a function temploid 2942/// specialization. 2943/// \param Pattern The templated declaration from which the instantiation 2944/// occurs. 2945/// \param TemplateArgs The template arguments to be substituted into 2946/// the pattern. 2947/// 2948/// \return \c true if an error occurred, \c false otherwise. 2949bool Sema::InstantiateInClassInitializer( 2950 SourceLocation PointOfInstantiation, FieldDecl *Instantiation, 2951 FieldDecl *Pattern, const MultiLevelTemplateArgumentList &TemplateArgs) { 2952 // If there is no initializer, we don't need to do anything. 2953 if (!Pattern->hasInClassInitializer()) 2954 return false; 2955 2956 assert(Instantiation->getInClassInitStyle() ==((void)0) 2957 Pattern->getInClassInitStyle() &&((void)0) 2958 "pattern and instantiation disagree about init style")((void)0); 2959 2960 // Error out if we haven't parsed the initializer of the pattern yet because 2961 // we are waiting for the closing brace of the outer class. 2962 Expr *OldInit = Pattern->getInClassInitializer(); 2963 if (!OldInit) { 2964 RecordDecl *PatternRD = Pattern->getParent(); 2965 RecordDecl *OutermostClass = PatternRD->getOuterLexicalRecordContext(); 2966 Diag(PointOfInstantiation, 2967 diag::err_default_member_initializer_not_yet_parsed) 2968 << OutermostClass << Pattern; 2969 Diag(Pattern->getEndLoc(), 2970 diag::note_default_member_initializer_not_yet_parsed); 2971 Instantiation->setInvalidDecl(); 2972 return true; 2973 } 2974 2975 InstantiatingTemplate Inst(*this, PointOfInstantiation, Instantiation); 2976 if (Inst.isInvalid()) 2977 return true; 2978 if (Inst.isAlreadyInstantiating()) { 2979 // Error out if we hit an instantiation cycle for this initializer. 2980 Diag(PointOfInstantiation, diag::err_default_member_initializer_cycle) 2981 << Instantiation; 2982 return true; 2983 } 2984 PrettyDeclStackTraceEntry CrashInfo(Context, Instantiation, SourceLocation(), 2985 "instantiating default member init"); 2986 2987 // Enter the scope of this instantiation. We don't use PushDeclContext because 2988 // we don't have a scope. 2989 ContextRAII SavedContext(*this, Instantiation->getParent()); 2990 EnterExpressionEvaluationContext EvalContext( 2991 *this, Sema::ExpressionEvaluationContext::PotentiallyEvaluated); 2992 2993 LocalInstantiationScope Scope(*this, true); 2994 2995 // Instantiate the initializer. 2996 ActOnStartCXXInClassMemberInitializer(); 2997 CXXThisScopeRAII ThisScope(*this, Instantiation->getParent(), Qualifiers()); 2998 2999 ExprResult NewInit = SubstInitializer(OldInit, TemplateArgs, 3000 /*CXXDirectInit=*/false); 3001 Expr *Init = NewInit.get(); 3002 assert((!Init || !isa<ParenListExpr>(Init)) && "call-style init in class")((void)0); 3003 ActOnFinishCXXInClassMemberInitializer( 3004 Instantiation, Init ? Init->getBeginLoc() : SourceLocation(), Init); 3005 3006 if (auto *L = getASTMutationListener()) 3007 L->DefaultMemberInitializerInstantiated(Instantiation); 3008 3009 // Return true if the in-class initializer is still missing. 3010 return !Instantiation->getInClassInitializer(); 3011} 3012 3013namespace { 3014 /// A partial specialization whose template arguments have matched 3015 /// a given template-id. 3016 struct PartialSpecMatchResult { 3017 ClassTemplatePartialSpecializationDecl *Partial; 3018 TemplateArgumentList *Args; 3019 }; 3020} 3021 3022bool Sema::usesPartialOrExplicitSpecialization( 3023 SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec) { 3024 if (ClassTemplateSpec->getTemplateSpecializationKind() == 3025 TSK_ExplicitSpecialization) 3026 return true; 3027 3028 SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs; 3029 ClassTemplateSpec->getSpecializedTemplate() 3030 ->getPartialSpecializations(PartialSpecs); 3031 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) { 3032 TemplateDeductionInfo Info(Loc); 3033 if (!DeduceTemplateArguments(PartialSpecs[I], 3034 ClassTemplateSpec->getTemplateArgs(), Info)) 3035 return true; 3036 } 3037 3038 return false; 3039} 3040 3041/// Get the instantiation pattern to use to instantiate the definition of a 3042/// given ClassTemplateSpecializationDecl (either the pattern of the primary 3043/// template or of a partial specialization). 3044static ActionResult<CXXRecordDecl *> 3045getPatternForClassTemplateSpecialization( 3046 Sema &S, SourceLocation PointOfInstantiation, 3047 ClassTemplateSpecializationDecl *ClassTemplateSpec, 3048 TemplateSpecializationKind TSK) { 3049 Sema::InstantiatingTemplate Inst(S, PointOfInstantiation, ClassTemplateSpec); 3050 if (Inst.isInvalid()) 3051 return {/*Invalid=*/true}; 3052 if (Inst.isAlreadyInstantiating()) 3053 return {/*Invalid=*/false}; 3054 3055 llvm::PointerUnion<ClassTemplateDecl *, 3056 ClassTemplatePartialSpecializationDecl *> 3057 Specialized = ClassTemplateSpec->getSpecializedTemplateOrPartial(); 3058 if (!Specialized.is<ClassTemplatePartialSpecializationDecl *>()) { 3059 // Find best matching specialization. 3060 ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate(); 3061 3062 // C++ [temp.class.spec.match]p1: 3063 // When a class template is used in a context that requires an 3064 // instantiation of the class, it is necessary to determine 3065 // whether the instantiation is to be generated using the primary 3066 // template or one of the partial specializations. This is done by 3067 // matching the template arguments of the class template 3068 // specialization with the template argument lists of the partial 3069 // specializations. 3070 typedef PartialSpecMatchResult MatchResult; 3071 SmallVector<MatchResult, 4> Matched; 3072 SmallVector<ClassTemplatePartialSpecializationDecl *, 4> PartialSpecs; 3073 Template->getPartialSpecializations(PartialSpecs); 3074 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation); 3075 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) { 3076 ClassTemplatePartialSpecializationDecl *Partial = PartialSpecs[I]; 3077 TemplateDeductionInfo Info(FailedCandidates.getLocation()); 3078 if (Sema::TemplateDeductionResult Result = S.DeduceTemplateArguments( 3079 Partial, ClassTemplateSpec->getTemplateArgs(), Info)) { 3080 // Store the failed-deduction information for use in diagnostics, later. 3081 // TODO: Actually use the failed-deduction info? 3082 FailedCandidates.addCandidate().set( 3083 DeclAccessPair::make(Template, AS_public), Partial, 3084 MakeDeductionFailureInfo(S.Context, Result, Info)); 3085 (void)Result; 3086 } else { 3087 Matched.push_back(PartialSpecMatchResult()); 3088 Matched.back().Partial = Partial; 3089 Matched.back().Args = Info.take(); 3090 } 3091 } 3092 3093 // If we're dealing with a member template where the template parameters 3094 // have been instantiated, this provides the original template parameters 3095 // from which the member template's parameters were instantiated. 3096 3097 if (Matched.size() >= 1) { 3098 SmallVectorImpl<MatchResult>::iterator Best = Matched.begin(); 3099 if (Matched.size() == 1) { 3100 // -- If exactly one matching specialization is found, the 3101 // instantiation is generated from that specialization. 3102 // We don't need to do anything for this. 3103 } else { 3104 // -- If more than one matching specialization is found, the 3105 // partial order rules (14.5.4.2) are used to determine 3106 // whether one of the specializations is more specialized 3107 // than the others. If none of the specializations is more 3108 // specialized than all of the other matching 3109 // specializations, then the use of the class template is 3110 // ambiguous and the program is ill-formed. 3111 for (SmallVectorImpl<MatchResult>::iterator P = Best + 1, 3112 PEnd = Matched.end(); 3113 P != PEnd; ++P) { 3114 if (S.getMoreSpecializedPartialSpecialization( 3115 P->Partial, Best->Partial, PointOfInstantiation) == 3116 P->Partial) 3117 Best = P; 3118 } 3119 3120 // Determine if the best partial specialization is more specialized than 3121 // the others. 3122 bool Ambiguous = false; 3123 for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(), 3124 PEnd = Matched.end(); 3125 P != PEnd; ++P) { 3126 if (P != Best && S.getMoreSpecializedPartialSpecialization( 3127 P->Partial, Best->Partial, 3128 PointOfInstantiation) != Best->Partial) { 3129 Ambiguous = true; 3130 break; 3131 } 3132 } 3133 3134 if (Ambiguous) { 3135 // Partial ordering did not produce a clear winner. Complain. 3136 Inst.Clear(); 3137 ClassTemplateSpec->setInvalidDecl(); 3138 S.Diag(PointOfInstantiation, 3139 diag::err_partial_spec_ordering_ambiguous) 3140 << ClassTemplateSpec; 3141 3142 // Print the matching partial specializations. 3143 for (SmallVectorImpl<MatchResult>::iterator P = Matched.begin(), 3144 PEnd = Matched.end(); 3145 P != PEnd; ++P) 3146 S.Diag(P->Partial->getLocation(), diag::note_partial_spec_match) 3147 << S.getTemplateArgumentBindingsText( 3148 P->Partial->getTemplateParameters(), *P->Args); 3149 3150 return {/*Invalid=*/true}; 3151 } 3152 } 3153 3154 ClassTemplateSpec->setInstantiationOf(Best->Partial, Best->Args); 3155 } else { 3156 // -- If no matches are found, the instantiation is generated 3157 // from the primary template. 3158 } 3159 } 3160 3161 CXXRecordDecl *Pattern = nullptr; 3162 Specialized = ClassTemplateSpec->getSpecializedTemplateOrPartial(); 3163 if (auto *PartialSpec = 3164 Specialized.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) { 3165 // Instantiate using the best class template partial specialization. 3166 while (PartialSpec->getInstantiatedFromMember()) { 3167 // If we've found an explicit specialization of this class template, 3168 // stop here and use that as the pattern. 3169 if (PartialSpec->isMemberSpecialization()) 3170 break; 3171 3172 PartialSpec = PartialSpec->getInstantiatedFromMember(); 3173 } 3174 Pattern = PartialSpec; 3175 } else { 3176 ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate(); 3177 while (Template->getInstantiatedFromMemberTemplate()) { 3178 // If we've found an explicit specialization of this class template, 3179 // stop here and use that as the pattern. 3180 if (Template->isMemberSpecialization()) 3181 break; 3182 3183 Template = Template->getInstantiatedFromMemberTemplate(); 3184 } 3185 Pattern = Template->getTemplatedDecl(); 3186 } 3187 3188 return Pattern; 3189} 3190 3191bool Sema::InstantiateClassTemplateSpecialization( 3192 SourceLocation PointOfInstantiation, 3193 ClassTemplateSpecializationDecl *ClassTemplateSpec, 3194 TemplateSpecializationKind TSK, bool Complain) { 3195 // Perform the actual instantiation on the canonical declaration. 3196 ClassTemplateSpec = cast<ClassTemplateSpecializationDecl>(

The object is a 'ClassTemplateSpecializationDecl'

→

3197 ClassTemplateSpec->getCanonicalDecl()); 3198 if (ClassTemplateSpec->isInvalidDecl())

←

Assuming the condition is false

→

←

Taking false branch

→

3199 return true; 3200 3201 ActionResult<CXXRecordDecl *> Pattern = 3202 getPatternForClassTemplateSpecialization(*this, PointOfInstantiation, 3203 ClassTemplateSpec, TSK); 3204 if (!Pattern.isUsable())

←

Assuming the condition is false

→

←

Taking false branch

→

3205 return Pattern.isInvalid(); 3206 3207 return InstantiateClass(

←

Calling 'Sema::InstantiateClass'

→

3208 PointOfInstantiation, ClassTemplateSpec, Pattern.get(), 3209 getTemplateInstantiationArgs(ClassTemplateSpec), TSK, Complain); 3210} 3211 3212/// Instantiates the definitions of all of the member 3213/// of the given class, which is an instantiation of a class template 3214/// or a member class of a template. 3215void 3216Sema::InstantiateClassMembers(SourceLocation PointOfInstantiation, 3217 CXXRecordDecl *Instantiation, 3218 const MultiLevelTemplateArgumentList &TemplateArgs, 3219 TemplateSpecializationKind TSK) { 3220 // FIXME: We need to notify the ASTMutationListener that we did all of these 3221 // things, in case we have an explicit instantiation definition in a PCM, a 3222 // module, or preamble, and the declaration is in an imported AST. 3223 assert(((void)0) 3224 (TSK == TSK_ExplicitInstantiationDefinition ||((void)0) 3225 TSK == TSK_ExplicitInstantiationDeclaration ||((void)0) 3226 (TSK == TSK_ImplicitInstantiation && Instantiation->isLocalClass())) &&((void)0) 3227 "Unexpected template specialization kind!")((void)0); 3228 for (auto *D : Instantiation->decls()) { 3229 bool SuppressNew = false; 3230 if (auto *Function = dyn_cast<FunctionDecl>(D)) { 3231 if (FunctionDecl *Pattern = 3232 Function->getInstantiatedFromMemberFunction()) { 3233 3234 if (Function->hasAttr<ExcludeFromExplicitInstantiationAttr>()) 3235 continue; 3236 3237 MemberSpecializationInfo *MSInfo = 3238 Function->getMemberSpecializationInfo(); 3239 assert(MSInfo && "No member specialization information?")((void)0); 3240 if (MSInfo->getTemplateSpecializationKind() 3241 == TSK_ExplicitSpecialization) 3242 continue; 3243 3244 if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, 3245 Function, 3246 MSInfo->getTemplateSpecializationKind(), 3247 MSInfo->getPointOfInstantiation(), 3248 SuppressNew) || 3249 SuppressNew) 3250 continue; 3251 3252 // C++11 [temp.explicit]p8: 3253 // An explicit instantiation definition that names a class template 3254 // specialization explicitly instantiates the class template 3255 // specialization and is only an explicit instantiation definition 3256 // of members whose definition is visible at the point of 3257 // instantiation. 3258 if (TSK == TSK_ExplicitInstantiationDefinition && !Pattern->isDefined()) 3259 continue; 3260 3261 Function->setTemplateSpecializationKind(TSK, PointOfInstantiation); 3262 3263 if (Function->isDefined()) { 3264 // Let the ASTConsumer know that this function has been explicitly 3265 // instantiated now, and its linkage might have changed. 3266 Consumer.HandleTopLevelDecl(DeclGroupRef(Function)); 3267 } else if (TSK == TSK_ExplicitInstantiationDefinition) { 3268 InstantiateFunctionDefinition(PointOfInstantiation, Function); 3269 } else if (TSK == TSK_ImplicitInstantiation) { 3270 PendingLocalImplicitInstantiations.push_back( 3271 std::make_pair(Function, PointOfInstantiation)); 3272 } 3273 } 3274 } else if (auto *Var = dyn_cast<VarDecl>(D)) { 3275 if (isa<VarTemplateSpecializationDecl>(Var)) 3276 continue; 3277 3278 if (Var->isStaticDataMember()) { 3279 if (Var->hasAttr<ExcludeFromExplicitInstantiationAttr>()) 3280 continue; 3281 3282 MemberSpecializationInfo *MSInfo = Var->getMemberSpecializationInfo(); 3283 assert(MSInfo && "No member specialization information?")((void)0); 3284 if (MSInfo->getTemplateSpecializationKind() 3285 == TSK_ExplicitSpecialization) 3286 continue; 3287 3288 if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, 3289 Var, 3290 MSInfo->getTemplateSpecializationKind(), 3291 MSInfo->getPointOfInstantiation(), 3292 SuppressNew) || 3293 SuppressNew) 3294 continue; 3295 3296 if (TSK == TSK_ExplicitInstantiationDefinition) { 3297 // C++0x [temp.explicit]p8: 3298 // An explicit instantiation definition that names a class template 3299 // specialization explicitly instantiates the class template 3300 // specialization and is only an explicit instantiation definition 3301 // of members whose definition is visible at the point of 3302 // instantiation. 3303 if (!Var->getInstantiatedFromStaticDataMember()->getDefinition()) 3304 continue; 3305 3306 Var->setTemplateSpecializationKind(TSK, PointOfInstantiation); 3307 InstantiateVariableDefinition(PointOfInstantiation, Var); 3308 } else { 3309 Var->setTemplateSpecializationKind(TSK, PointOfInstantiation); 3310 } 3311 } 3312 } else if (auto *Record = dyn_cast<CXXRecordDecl>(D)) { 3313 if (Record->hasAttr<ExcludeFromExplicitInstantiationAttr>()) 3314 continue; 3315 3316 // Always skip the injected-class-name, along with any 3317 // redeclarations of nested classes, since both would cause us 3318 // to try to instantiate the members of a class twice. 3319 // Skip closure types; they'll get instantiated when we instantiate 3320 // the corresponding lambda-expression. 3321 if (Record->isInjectedClassName() || Record->getPreviousDecl() || 3322 Record->isLambda()) 3323 continue; 3324 3325 MemberSpecializationInfo *MSInfo = Record->getMemberSpecializationInfo(); 3326 assert(MSInfo && "No member specialization information?")((void)0); 3327 3328 if (MSInfo->getTemplateSpecializationKind() 3329 == TSK_ExplicitSpecialization) 3330 continue; 3331 3332 if (Context.getTargetInfo().getTriple().isOSWindows() && 3333 TSK == TSK_ExplicitInstantiationDeclaration) { 3334 // On Windows, explicit instantiation decl of the outer class doesn't 3335 // affect the inner class. Typically extern template declarations are 3336 // used in combination with dll import/export annotations, but those 3337 // are not propagated from the outer class templates to inner classes. 3338 // Therefore, do not instantiate inner classes on this platform, so 3339 // that users don't end up with undefined symbols during linking. 3340 continue; 3341 } 3342 3343 if (CheckSpecializationInstantiationRedecl(PointOfInstantiation, TSK, 3344 Record, 3345 MSInfo->getTemplateSpecializationKind(), 3346 MSInfo->getPointOfInstantiation(), 3347 SuppressNew) || 3348 SuppressNew) 3349 continue; 3350 3351 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass(); 3352 assert(Pattern && "Missing instantiated-from-template information")((void)0); 3353 3354 if (!Record->getDefinition()) { 3355 if (!Pattern->getDefinition()) { 3356 // C++0x [temp.explicit]p8: 3357 // An explicit instantiation definition that names a class template 3358 // specialization explicitly instantiates the class template 3359 // specialization and is only an explicit instantiation definition 3360 // of members whose definition is visible at the point of 3361 // instantiation. 3362 if (TSK == TSK_ExplicitInstantiationDeclaration) { 3363 MSInfo->setTemplateSpecializationKind(TSK); 3364 MSInfo->setPointOfInstantiation(PointOfInstantiation); 3365 } 3366 3367 continue; 3368 } 3369 3370 InstantiateClass(PointOfInstantiation, Record, Pattern, 3371 TemplateArgs, 3372 TSK); 3373 } else { 3374 if (TSK == TSK_ExplicitInstantiationDefinition && 3375 Record->getTemplateSpecializationKind() == 3376 TSK_ExplicitInstantiationDeclaration) { 3377 Record->setTemplateSpecializationKind(TSK); 3378 MarkVTableUsed(PointOfInstantiation, Record, true); 3379 } 3380 } 3381 3382 Pattern = cast_or_null<CXXRecordDecl>(Record->getDefinition()); 3383 if (Pattern) 3384 InstantiateClassMembers(PointOfInstantiation, Pattern, TemplateArgs, 3385 TSK); 3386 } else if (auto *Enum = dyn_cast<EnumDecl>(D)) { 3387 MemberSpecializationInfo *MSInfo = Enum->getMemberSpecializationInfo(); 3388 assert(MSInfo && "No member specialization information?")((void)0); 3389 3390 if (MSInfo->getTemplateSpecializationKind() 3391 == TSK_ExplicitSpecialization) 3392 continue; 3393 3394 if (CheckSpecializationInstantiationRedecl( 3395 PointOfInstantiation, TSK, Enum, 3396 MSInfo->getTemplateSpecializationKind(), 3397 MSInfo->getPointOfInstantiation(), SuppressNew) || 3398 SuppressNew) 3399 continue; 3400 3401 if (Enum->getDefinition()) 3402 continue; 3403 3404 EnumDecl *Pattern = Enum->getTemplateInstantiationPattern(); 3405 assert(Pattern && "Missing instantiated-from-template information")((void)0); 3406 3407 if (TSK == TSK_ExplicitInstantiationDefinition) { 3408 if (!Pattern->getDefinition()) 3409 continue; 3410 3411 InstantiateEnum(PointOfInstantiation, Enum, Pattern, TemplateArgs, TSK); 3412 } else { 3413 MSInfo->setTemplateSpecializationKind(TSK); 3414 MSInfo->setPointOfInstantiation(PointOfInstantiation); 3415 } 3416 } else if (auto *Field = dyn_cast<FieldDecl>(D)) { 3417 // No need to instantiate in-class initializers during explicit 3418 // instantiation. 3419 if (Field->hasInClassInitializer() && TSK == TSK_ImplicitInstantiation) { 3420 CXXRecordDecl *ClassPattern = 3421 Instantiation->getTemplateInstantiationPattern(); 3422 DeclContext::lookup_result Lookup = 3423 ClassPattern->lookup(Field->getDeclName()); 3424 FieldDecl *Pattern = Lookup.find_first<FieldDecl>(); 3425 assert(Pattern)((void)0); 3426 InstantiateInClassInitializer(PointOfInstantiation, Field, Pattern, 3427 TemplateArgs); 3428 } 3429 } 3430 } 3431} 3432 3433/// Instantiate the definitions of all of the members of the 3434/// given class template specialization, which was named as part of an 3435/// explicit instantiation. 3436void 3437Sema::InstantiateClassTemplateSpecializationMembers( 3438 SourceLocation PointOfInstantiation, 3439 ClassTemplateSpecializationDecl *ClassTemplateSpec, 3440 TemplateSpecializationKind TSK) { 3441 // C++0x [temp.explicit]p7: 3442 // An explicit instantiation that names a class template 3443 // specialization is an explicit instantion of the same kind 3444 // (declaration or definition) of each of its members (not 3445 // including members inherited from base classes) that has not 3446 // been previously explicitly specialized in the translation unit 3447 // containing the explicit instantiation, except as described 3448 // below. 3449 InstantiateClassMembers(PointOfInstantiation, ClassTemplateSpec, 3450 getTemplateInstantiationArgs(ClassTemplateSpec), 3451 TSK); 3452} 3453 3454StmtResult 3455Sema::SubstStmt(Stmt *S, const MultiLevelTemplateArgumentList &TemplateArgs) { 3456 if (!S) 3457 return S; 3458 3459 TemplateInstantiator Instantiator(*this, TemplateArgs, 3460 SourceLocation(), 3461 DeclarationName()); 3462 return Instantiator.TransformStmt(S); 3463} 3464 3465bool Sema::SubstTemplateArguments( 3466 ArrayRef<TemplateArgumentLoc> Args, 3467 const MultiLevelTemplateArgumentList &TemplateArgs, 3468 TemplateArgumentListInfo &Out) { 3469 TemplateInstantiator Instantiator(*this, TemplateArgs, 3470 SourceLocation(), 3471 DeclarationName()); 3472 return Instantiator.TransformTemplateArguments(Args.begin(), Args.end(), 3473 Out); 3474} 3475 3476ExprResult 3477Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) { 3478 if (!E) 3479 return E; 3480 3481 TemplateInstantiator Instantiator(*this, TemplateArgs, 3482 SourceLocation(), 3483 DeclarationName()); 3484 return Instantiator.TransformExpr(E); 3485} 3486 3487ExprResult Sema::SubstInitializer(Expr *Init, 3488 const MultiLevelTemplateArgumentList &TemplateArgs, 3489 bool CXXDirectInit) { 3490 TemplateInstantiator Instantiator(*this, TemplateArgs, 3491 SourceLocation(), 3492 DeclarationName()); 3493 return Instantiator.TransformInitializer(Init, CXXDirectInit); 3494} 3495 3496bool Sema::SubstExprs(ArrayRef<Expr *> Exprs, bool IsCall, 3497 const MultiLevelTemplateArgumentList &TemplateArgs, 3498 SmallVectorImpl<Expr *> &Outputs) { 3499 if (Exprs.empty()) 3500 return false; 3501 3502 TemplateInstantiator Instantiator(*this, TemplateArgs, 3503 SourceLocation(), 3504 DeclarationName()); 3505 return Instantiator.TransformExprs(Exprs.data(), Exprs.size(), 3506 IsCall, Outputs); 3507} 3508 3509NestedNameSpecifierLoc 3510Sema::SubstNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS, 3511 const MultiLevelTemplateArgumentList &TemplateArgs) { 3512 if (!NNS) 3513 return NestedNameSpecifierLoc(); 3514 3515 TemplateInstantiator Instantiator(*this, TemplateArgs, NNS.getBeginLoc(), 3516 DeclarationName()); 3517 return Instantiator.TransformNestedNameSpecifierLoc(NNS); 3518} 3519 3520/// Do template substitution on declaration name info. 3521DeclarationNameInfo 3522Sema::SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo, 3523 const MultiLevelTemplateArgumentList &TemplateArgs) { 3524 TemplateInstantiator Instantiator(*this, TemplateArgs, NameInfo.getLoc(), 3525 NameInfo.getName()); 3526 return Instantiator.TransformDeclarationNameInfo(NameInfo); 3527} 3528 3529TemplateName 3530Sema::SubstTemplateName(NestedNameSpecifierLoc QualifierLoc, 3531 TemplateName Name, SourceLocation Loc, 3532 const MultiLevelTemplateArgumentList &TemplateArgs) { 3533 TemplateInstantiator Instantiator(*this, TemplateArgs, Loc, 3534 DeclarationName()); 3535 CXXScopeSpec SS; 3536 SS.Adopt(QualifierLoc); 3537 return Instantiator.TransformTemplateName(SS, Name, Loc); 3538} 3539 3540bool Sema::Subst(const TemplateArgumentLoc *Args, unsigned NumArgs, 3541 TemplateArgumentListInfo &Result, 3542 const MultiLevelTemplateArgumentList &TemplateArgs) { 3543 TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), 3544 DeclarationName()); 3545 3546 return Instantiator.TransformTemplateArguments(Args, NumArgs, Result); 3547} 3548 3549static const Decl *getCanonicalParmVarDecl(const Decl *D) { 3550 // When storing ParmVarDecls in the local instantiation scope, we always 3551 // want to use the ParmVarDecl from the canonical function declaration, 3552 // since the map is then valid for any redeclaration or definition of that 3553 // function. 3554 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(D)) { 3555 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) { 3556 unsigned i = PV->getFunctionScopeIndex(); 3557 // This parameter might be from a freestanding function type within the 3558 // function and isn't necessarily referring to one of FD's parameters. 3559 if (i < FD->getNumParams() && FD->getParamDecl(i) == PV) 3560 return FD->getCanonicalDecl()->getParamDecl(i); 3561 } 3562 } 3563 return D; 3564} 3565 3566 3567llvm::PointerUnion<Decl *, LocalInstantiationScope::DeclArgumentPack *> * 3568LocalInstantiationScope::findInstantiationOf(const Decl *D) { 3569 D = getCanonicalParmVarDecl(D); 3570 for (LocalInstantiationScope *Current = this; Current; 3571 Current = Current->Outer) { 3572 3573 // Check if we found something within this scope. 3574 const Decl *CheckD = D; 3575 do { 3576 LocalDeclsMap::iterator Found = Current->LocalDecls.find(CheckD); 3577 if (Found != Current->LocalDecls.end()) 3578 return &Found->second; 3579 3580 // If this is a tag declaration, it's possible that we need to look for 3581 // a previous declaration. 3582 if (const TagDecl *Tag = dyn_cast<TagDecl>(CheckD)) 3583 CheckD = Tag->getPreviousDecl(); 3584 else 3585 CheckD = nullptr; 3586 } while (CheckD); 3587 3588 // If we aren't combined with our outer scope, we're done. 3589 if (!Current->CombineWithOuterScope) 3590 break; 3591 } 3592 3593 // If we're performing a partial substitution during template argument 3594 // deduction, we may not have values for template parameters yet. 3595 if (isa<NonTypeTemplateParmDecl>(D) || isa<TemplateTypeParmDecl>(D) || 3596 isa<TemplateTemplateParmDecl>(D)) 3597 return nullptr; 3598 3599 // Local types referenced prior to definition may require instantiation. 3600 if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) 3601 if (RD->isLocalClass()) 3602 return nullptr; 3603 3604 // Enumeration types referenced prior to definition may appear as a result of 3605 // error recovery. 3606 if (isa<EnumDecl>(D)) 3607 return nullptr; 3608 3609 // Materialized typedefs/type alias for implicit deduction guides may require 3610 // instantiation. 3611 if (isa<TypedefNameDecl>(D) && 3612 isa<CXXDeductionGuideDecl>(D->getDeclContext())) 3613 return nullptr; 3614 3615 // If we didn't find the decl, then we either have a sema bug, or we have a 3616 // forward reference to a label declaration. Return null to indicate that 3617 // we have an uninstantiated label. 3618 assert(isa<LabelDecl>(D) && "declaration not instantiated in this scope")((void)0); 3619 return nullptr; 3620} 3621 3622void LocalInstantiationScope::InstantiatedLocal(const Decl *D, Decl *Inst) { 3623 D = getCanonicalParmVarDecl(D); 3624 llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D]; 3625 if (Stored.isNull()) { 3626#ifndef NDEBUG1 3627 // It should not be present in any surrounding scope either. 3628 LocalInstantiationScope *Current = this; 3629 while (Current->CombineWithOuterScope && Current->Outer) { 3630 Current = Current->Outer; 3631 assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() &&((void)0) 3632 "Instantiated local in inner and outer scopes")((void)0); 3633 } 3634#endif 3635 Stored = Inst; 3636 } else if (DeclArgumentPack *Pack = Stored.dyn_cast<DeclArgumentPack *>()) { 3637 Pack->push_back(cast<VarDecl>(Inst)); 3638 } else { 3639 assert(Stored.get<Decl *>() == Inst && "Already instantiated this local")((void)0); 3640 } 3641} 3642 3643void LocalInstantiationScope::InstantiatedLocalPackArg(const Decl *D, 3644 VarDecl *Inst) { 3645 D = getCanonicalParmVarDecl(D); 3646 DeclArgumentPack *Pack = LocalDecls[D].get<DeclArgumentPack *>(); 3647 Pack->push_back(Inst); 3648} 3649 3650void LocalInstantiationScope::MakeInstantiatedLocalArgPack(const Decl *D) { 3651#ifndef NDEBUG1 3652 // This should be the first time we've been told about this decl. 3653 for (LocalInstantiationScope *Current = this; 3654 Current && Current->CombineWithOuterScope; Current = Current->Outer) 3655 assert(Current->LocalDecls.find(D) == Current->LocalDecls.end() &&((void)0) 3656 "Creating local pack after instantiation of local")((void)0); 3657#endif 3658 3659 D = getCanonicalParmVarDecl(D); 3660 llvm::PointerUnion<Decl *, DeclArgumentPack *> &Stored = LocalDecls[D]; 3661 DeclArgumentPack *Pack = new DeclArgumentPack; 3662 Stored = Pack; 3663 ArgumentPacks.push_back(Pack); 3664} 3665 3666bool LocalInstantiationScope::isLocalPackExpansion(const Decl *D) { 3667 for (DeclArgumentPack *Pack : ArgumentPacks) 3668 if (std::find(Pack->begin(), Pack->end(), D) != Pack->end()) 3669 return true; 3670 return false; 3671} 3672 3673void LocalInstantiationScope::SetPartiallySubstitutedPack(NamedDecl *Pack, 3674 const TemplateArgument *ExplicitArgs, 3675 unsigned NumExplicitArgs) { 3676 assert((!PartiallySubstitutedPack || PartiallySubstitutedPack == Pack) &&((void)0) 3677 "Already have a partially-substituted pack")((void)0); 3678 assert((!PartiallySubstitutedPack((void)0) 3679 || NumArgsInPartiallySubstitutedPack == NumExplicitArgs) &&((void)0) 3680 "Wrong number of arguments in partially-substituted pack")((void)0); 3681 PartiallySubstitutedPack = Pack; 3682 ArgsInPartiallySubstitutedPack = ExplicitArgs; 3683 NumArgsInPartiallySubstitutedPack = NumExplicitArgs; 3684} 3685 3686NamedDecl *LocalInstantiationScope::getPartiallySubstitutedPack( 3687 const TemplateArgument **ExplicitArgs, 3688 unsigned *NumExplicitArgs) const { 3689 if (ExplicitArgs) 3690 *ExplicitArgs = nullptr; 3691 if (NumExplicitArgs) 3692 *NumExplicitArgs = 0; 3693 3694 for (const LocalInstantiationScope *Current = this; Current; 3695 Current = Current->Outer) { 3696 if (Current->PartiallySubstitutedPack) { 3697 if (ExplicitArgs) 3698 *ExplicitArgs = Current->ArgsInPartiallySubstitutedPack; 3699 if (NumExplicitArgs) 3700 *NumExplicitArgs = Current->NumArgsInPartiallySubstitutedPack; 3701 3702 return Current->PartiallySubstitutedPack; 3703 } 3704 3705 if (!Current->CombineWithOuterScope) 3706 break; 3707 } 3708 3709 return nullptr; 3710}

←

/usr/src/gnu/usr.bin/clang/libclangSema/../../../llvm/clang/include/clang/Sema/Sema.h

1	//===--- Sema.h - Semantic Analysis & AST Building --------------- C++ --===//
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-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// This file defines the Sema class, which performs semantic analysis and
10	// builds ASTs.
11	//
12	//===----------------------------------------------------------------------===//
13
14	#ifndef LLVM_CLANG_SEMA_SEMA_H
15	#define LLVM_CLANG_SEMA_SEMA_H
16
17	#include "clang/AST/ASTConcept.h"
18	#include "clang/AST/ASTFwd.h"
19	#include "clang/AST/Attr.h"
20	#include "clang/AST/Availability.h"
21	#include "clang/AST/ComparisonCategories.h"
22	#include "clang/AST/DeclTemplate.h"
23	#include "clang/AST/DeclarationName.h"
24	#include "clang/AST/Expr.h"
25	#include "clang/AST/ExprCXX.h"
26	#include "clang/AST/ExprConcepts.h"
27	#include "clang/AST/ExprObjC.h"
28	#include "clang/AST/ExprOpenMP.h"
29	#include "clang/AST/ExternalASTSource.h"
30	#include "clang/AST/LocInfoType.h"
31	#include "clang/AST/MangleNumberingContext.h"
32	#include "clang/AST/NSAPI.h"
33	#include "clang/AST/PrettyPrinter.h"
34	#include "clang/AST/StmtCXX.h"
35	#include "clang/AST/StmtOpenMP.h"
36	#include "clang/AST/TypeLoc.h"
37	#include "clang/AST/TypeOrdering.h"
38	#include "clang/Basic/BitmaskEnum.h"
39	#include "clang/Basic/Builtins.h"
40	#include "clang/Basic/DarwinSDKInfo.h"
41	#include "clang/Basic/ExpressionTraits.h"
42	#include "clang/Basic/Module.h"
43	#include "clang/Basic/OpenCLOptions.h"
44	#include "clang/Basic/OpenMPKinds.h"
45	#include "clang/Basic/PragmaKinds.h"
46	#include "clang/Basic/Specifiers.h"
47	#include "clang/Basic/TemplateKinds.h"
48	#include "clang/Basic/TypeTraits.h"
49	#include "clang/Sema/AnalysisBasedWarnings.h"
50	#include "clang/Sema/CleanupInfo.h"
51	#include "clang/Sema/DeclSpec.h"
52	#include "clang/Sema/ExternalSemaSource.h"
53	#include "clang/Sema/IdentifierResolver.h"
54	#include "clang/Sema/ObjCMethodList.h"
55	#include "clang/Sema/Ownership.h"
56	#include "clang/Sema/Scope.h"
57	#include "clang/Sema/SemaConcept.h"
58	#include "clang/Sema/TypoCorrection.h"
59	#include "clang/Sema/Weak.h"
60	#include "llvm/ADT/ArrayRef.h"
61	#include "llvm/ADT/Optional.h"
62	#include "llvm/ADT/SetVector.h"
63	#include "llvm/ADT/SmallBitVector.h"
64	#include "llvm/ADT/SmallPtrSet.h"
65	#include "llvm/ADT/SmallSet.h"
66	#include "llvm/ADT/SmallVector.h"
67	#include "llvm/ADT/TinyPtrVector.h"
68	#include "llvm/Frontend/OpenMP/OMPConstants.h"
69	#include <deque>
70	#include <memory>
71	#include <string>
72	#include <tuple>
73	#include <vector>
74
75	namespace llvm {
76	class APSInt;
77	template <typename ValueT> struct DenseMapInfo;
78	template <typename ValueT, typename ValueInfoT> class DenseSet;
79	class SmallBitVector;
80	struct InlineAsmIdentifierInfo;
81	}
82
83	namespace clang {
84	class ADLResult;
85	class ASTConsumer;
86	class ASTContext;
87	class ASTMutationListener;
88	class ASTReader;
89	class ASTWriter;
90	class ArrayType;
91	class ParsedAttr;
92	class BindingDecl;
93	class BlockDecl;
94	class CapturedDecl;
95	class CXXBasePath;
96	class CXXBasePaths;
97	class CXXBindTemporaryExpr;
98	typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
99	class CXXConstructorDecl;
100	class CXXConversionDecl;
101	class CXXDeleteExpr;
102	class CXXDestructorDecl;
103	class CXXFieldCollector;
104	class CXXMemberCallExpr;
105	class CXXMethodDecl;
106	class CXXScopeSpec;
107	class CXXTemporary;
108	class CXXTryStmt;
109	class CallExpr;
110	class ClassTemplateDecl;
111	class ClassTemplatePartialSpecializationDecl;
112	class ClassTemplateSpecializationDecl;
113	class VarTemplatePartialSpecializationDecl;
114	class CodeCompleteConsumer;
115	class CodeCompletionAllocator;
116	class CodeCompletionTUInfo;
117	class CodeCompletionResult;
118	class CoroutineBodyStmt;
119	class Decl;
120	class DeclAccessPair;
121	class DeclContext;
122	class DeclRefExpr;
123	class DeclaratorDecl;
124	class DeducedTemplateArgument;
125	class DependentDiagnostic;
126	class DesignatedInitExpr;
127	class Designation;
128	class EnableIfAttr;
129	class EnumConstantDecl;
130	class Expr;
131	class ExtVectorType;
132	class FormatAttr;
133	class FriendDecl;
134	class FunctionDecl;
135	class FunctionProtoType;
136	class FunctionTemplateDecl;
137	class ImplicitConversionSequence;
138	typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
139	class InitListExpr;
140	class InitializationKind;
141	class InitializationSequence;
142	class InitializedEntity;
143	class IntegerLiteral;
144	class LabelStmt;
145	class LambdaExpr;
146	class LangOptions;
147	class LocalInstantiationScope;
148	class LookupResult;
149	class MacroInfo;
150	typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation>> ModuleIdPath;
151	class ModuleLoader;
152	class MultiLevelTemplateArgumentList;
153	class NamedDecl;
154	class ObjCCategoryDecl;
155	class ObjCCategoryImplDecl;
156	class ObjCCompatibleAliasDecl;
157	class ObjCContainerDecl;
158	class ObjCImplDecl;
159	class ObjCImplementationDecl;
160	class ObjCInterfaceDecl;
161	class ObjCIvarDecl;
162	template <class T> class ObjCList;
163	class ObjCMessageExpr;
164	class ObjCMethodDecl;
165	class ObjCPropertyDecl;
166	class ObjCProtocolDecl;
167	class OMPThreadPrivateDecl;
168	class OMPRequiresDecl;
169	class OMPDeclareReductionDecl;
170	class OMPDeclareSimdDecl;
171	class OMPClause;
172	struct OMPVarListLocTy;
173	struct OverloadCandidate;
174	enum class OverloadCandidateParamOrder : char;
175	enum OverloadCandidateRewriteKind : unsigned;
176	class OverloadCandidateSet;
177	class OverloadExpr;
178	class ParenListExpr;
179	class ParmVarDecl;
180	class Preprocessor;
181	class PseudoDestructorTypeStorage;
182	class PseudoObjectExpr;
183	class QualType;
184	class StandardConversionSequence;
185	class Stmt;
186	class StringLiteral;
187	class SwitchStmt;
188	class TemplateArgument;
189	class TemplateArgumentList;
190	class TemplateArgumentLoc;
191	class TemplateDecl;
192	class TemplateInstantiationCallback;
193	class TemplateParameterList;
194	class TemplatePartialOrderingContext;
195	class TemplateTemplateParmDecl;
196	class Token;
197	class TypeAliasDecl;
198	class TypedefDecl;
199	class TypedefNameDecl;
200	class TypeLoc;
201	class TypoCorrectionConsumer;
202	class UnqualifiedId;
203	class UnresolvedLookupExpr;
204	class UnresolvedMemberExpr;
205	class UnresolvedSetImpl;
206	class UnresolvedSetIterator;
207	class UsingDecl;
208	class UsingShadowDecl;
209	class ValueDecl;
210	class VarDecl;
211	class VarTemplateSpecializationDecl;
212	class VisibilityAttr;
213	class VisibleDeclConsumer;
214	class IndirectFieldDecl;
215	struct DeductionFailureInfo;
216	class TemplateSpecCandidateSet;
217
218	namespace sema {
219	class AccessedEntity;
220	class BlockScopeInfo;
221	class Capture;
222	class CapturedRegionScopeInfo;
223	class CapturingScopeInfo;
224	class CompoundScopeInfo;
225	class DelayedDiagnostic;
226	class DelayedDiagnosticPool;
227	class FunctionScopeInfo;
228	class LambdaScopeInfo;
229	class PossiblyUnreachableDiag;
230	class SemaPPCallbacks;
231	class TemplateDeductionInfo;
232	}
233
234	namespace threadSafety {
235	class BeforeSet;
236	void threadSafetyCleanup(BeforeSet* Cache);
237	}
238
239	// FIXME: No way to easily map from TemplateTypeParmTypes to
240	// TemplateTypeParmDecls, so we have this horrible PointerUnion.
241	typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType, NamedDecl>,
242	SourceLocation> UnexpandedParameterPack;
243
244	/// Describes whether we've seen any nullability information for the given
245	/// file.
246	struct FileNullability {
247	/// The first pointer declarator (of any pointer kind) in the file that does
248	/// not have a corresponding nullability annotation.
249	SourceLocation PointerLoc;
250
251	/// The end location for the first pointer declarator in the file. Used for
252	/// placing fix-its.
253	SourceLocation PointerEndLoc;
254
255	/// Which kind of pointer declarator we saw.
256	uint8_t PointerKind;
257
258	/// Whether we saw any type nullability annotations in the given file.
259	bool SawTypeNullability = false;
260	};
261
262	/// A mapping from file IDs to a record of whether we've seen nullability
263	/// information in that file.
264	class FileNullabilityMap {
265	/// A mapping from file IDs to the nullability information for each file ID.
266	llvm::DenseMap<FileID, FileNullability> Map;
267
268	/// A single-element cache based on the file ID.
269	struct {
270	FileID File;
271	FileNullability Nullability;
272	} Cache;
273
274	public:
275	FileNullability &operator[](FileID file) {
276	// Check the single-element cache.
277	if (file == Cache.File)
278	return Cache.Nullability;
279
280	// It's not in the single-element cache; flush the cache if we have one.
281	if (!Cache.File.isInvalid()) {
282	Map[Cache.File] = Cache.Nullability;
283	}
284
285	// Pull this entry into the cache.
286	Cache.File = file;
287	Cache.Nullability = Map[file];
288	return Cache.Nullability;
289	}
290	};
291
292	/// Tracks expected type during expression parsing, for use in code completion.
293	/// The type is tied to a particular token, all functions that update or consume
294	/// the type take a start location of the token they are looking at as a
295	/// parameter. This avoids updating the type on hot paths in the parser.
296	class PreferredTypeBuilder {
297	public:
298	PreferredTypeBuilder(bool Enabled) : Enabled(Enabled) {}
299
300	void enterCondition(Sema &S, SourceLocation Tok);
301	void enterReturn(Sema &S, SourceLocation Tok);
302	void enterVariableInit(SourceLocation Tok, Decl *D);
303	/// Handles e.g. BaseType{ .D = Tok...
304	void enterDesignatedInitializer(SourceLocation Tok, QualType BaseType,
305	const Designation &D);
306	/// Computing a type for the function argument may require running
307	/// overloading, so we postpone its computation until it is actually needed.
308	///
309	/// Clients should be very careful when using this funciton, as it stores a
310	/// function_ref, clients should make sure all calls to get() with the same
311	/// location happen while function_ref is alive.
312	///
313	/// The callback should also emit signature help as a side-effect, but only
314	/// if the completion point has been reached.
315	void enterFunctionArgument(SourceLocation Tok,
316	llvm::function_ref<QualType()> ComputeType);
317
318	void enterParenExpr(SourceLocation Tok, SourceLocation LParLoc);
319	void enterUnary(Sema &S, SourceLocation Tok, tok::TokenKind OpKind,
320	SourceLocation OpLoc);
321	void enterBinary(Sema &S, SourceLocation Tok, Expr *LHS, tok::TokenKind Op);
322	void enterMemAccess(Sema &S, SourceLocation Tok, Expr *Base);
323	void enterSubscript(Sema &S, SourceLocation Tok, Expr *LHS);
324	/// Handles all type casts, including C-style cast, C++ casts, etc.
325	void enterTypeCast(SourceLocation Tok, QualType CastType);
326
327	/// Get the expected type associated with this location, if any.
328	///
329	/// If the location is a function argument, determining the expected type
330	/// involves considering all function overloads and the arguments so far.
331	/// In this case, signature help for these function overloads will be reported
332	/// as a side-effect (only if the completion point has been reached).
333	QualType get(SourceLocation Tok) const {
334	if (!Enabled \|\| Tok != ExpectedLoc)
335	return QualType();
336	if (!Type.isNull())
337	return Type;
338	if (ComputeType)
339	return ComputeType();
340	return QualType();
341	}
342
343	private:
344	bool Enabled;
345	/// Start position of a token for which we store expected type.
346	SourceLocation ExpectedLoc;
347	/// Expected type for a token starting at ExpectedLoc.
348	QualType Type;
349	/// A function to compute expected type at ExpectedLoc. It is only considered
350	/// if Type is null.
351	llvm::function_ref<QualType()> ComputeType;
352	};
353
354	/// Sema - This implements semantic analysis and AST building for C.
355	class Sema final {
356	Sema(const Sema &) = delete;
357	void operator=(const Sema &) = delete;
358
359	///Source of additional semantic information.
360	ExternalSemaSource *ExternalSource;
361
362	///Whether Sema has generated a multiplexer and has to delete it.
363	bool isMultiplexExternalSource;
364
365	static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);
366
367	bool isVisibleSlow(const NamedDecl *D);
368
369	/// Determine whether two declarations should be linked together, given that
370	/// the old declaration might not be visible and the new declaration might
371	/// not have external linkage.
372	bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
373	const NamedDecl *New) {
374	if (isVisible(Old))
375	return true;
376	// See comment in below overload for why it's safe to compute the linkage
377	// of the new declaration here.
378	if (New->isExternallyDeclarable()) {
379	assert(Old->isExternallyDeclarable() &&((void)0)
380	"should not have found a non-externally-declarable previous decl")((void)0);
381	return true;
382	}
383	return false;
384	}
385	bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);
386
387	void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
388	QualType ResultTy,
389	ArrayRef<QualType> Args);
390
391	public:
392	/// The maximum alignment, same as in llvm::Value. We duplicate them here
393	/// because that allows us not to duplicate the constants in clang code,
394	/// which we must to since we can't directly use the llvm constants.
395	/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
396	///
397	/// This is the greatest alignment value supported by load, store, and alloca
398	/// instructions, and global values.
399	static const unsigned MaxAlignmentExponent = 29;
400	static const unsigned MaximumAlignment = 1u << MaxAlignmentExponent;
401
402	typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
403	typedef OpaquePtr<TemplateName> TemplateTy;
404	typedef OpaquePtr<QualType> TypeTy;
405
406	OpenCLOptions OpenCLFeatures;
407	FPOptions CurFPFeatures;
408
409	const LangOptions &LangOpts;
410	Preprocessor &PP;
411	ASTContext &Context;
412	ASTConsumer &Consumer;
413	DiagnosticsEngine &Diags;
414	SourceManager &SourceMgr;
415
416	/// Flag indicating whether or not to collect detailed statistics.
417	bool CollectStats;
418
419	/// Code-completion consumer.
420	CodeCompleteConsumer *CodeCompleter;
421
422	/// CurContext - This is the current declaration context of parsing.
423	DeclContext *CurContext;
424
425	/// Generally null except when we temporarily switch decl contexts,
426	/// like in \see ActOnObjCTemporaryExitContainerContext.
427	DeclContext *OriginalLexicalContext;
428
429	/// VAListTagName - The declaration name corresponding to __va_list_tag.
430	/// This is used as part of a hack to omit that class from ADL results.
431	DeclarationName VAListTagName;
432
433	bool MSStructPragmaOn; // True when \#pragma ms_struct on
434
435	/// Controls member pointer representation format under the MS ABI.
436	LangOptions::PragmaMSPointersToMembersKind
437	MSPointerToMemberRepresentationMethod;
438
439	/// Stack of active SEH __finally scopes. Can be empty.
440	SmallVector<Scope*, 2> CurrentSEHFinally;
441
442	/// Source location for newly created implicit MSInheritanceAttrs
443	SourceLocation ImplicitMSInheritanceAttrLoc;
444
445	/// Holds TypoExprs that are created from `createDelayedTypo`. This is used by
446	/// `TransformTypos` in order to keep track of any TypoExprs that are created
447	/// recursively during typo correction and wipe them away if the correction
448	/// fails.
449	llvm::SmallVector<TypoExpr *, 2> TypoExprs;
450
451	/// pragma clang section kind
452	enum PragmaClangSectionKind {
453	PCSK_Invalid = 0,
454	PCSK_BSS = 1,
455	PCSK_Data = 2,
456	PCSK_Rodata = 3,
457	PCSK_Text = 4,
458	PCSK_Relro = 5
459	};
460
461	enum PragmaClangSectionAction {
462	PCSA_Set = 0,
463	PCSA_Clear = 1
464	};
465
466	struct PragmaClangSection {
467	std::string SectionName;
468	bool Valid = false;
469	SourceLocation PragmaLocation;
470	};
471
472	PragmaClangSection PragmaClangBSSSection;
473	PragmaClangSection PragmaClangDataSection;
474	PragmaClangSection PragmaClangRodataSection;
475	PragmaClangSection PragmaClangRelroSection;
476	PragmaClangSection PragmaClangTextSection;
477
478	enum PragmaMsStackAction {
479	PSK_Reset = 0x0, // #pragma ()
480	PSK_Set = 0x1, // #pragma (value)
481	PSK_Push = 0x2, // #pragma (push[, id])
482	PSK_Pop = 0x4, // #pragma (pop[, id])
483	PSK_Show = 0x8, // #pragma (show) -- only for "pack"!
484	PSK_Push_Set = PSK_Push \| PSK_Set, // #pragma (push[, id], value)
485	PSK_Pop_Set = PSK_Pop \| PSK_Set, // #pragma (pop[, id], value)
486	};
487
488	// #pragma pack and align.
489	class AlignPackInfo {
490	public:
491	// `Native` represents default align mode, which may vary based on the
492	// platform.
493	enum Mode : unsigned char { Native, Natural, Packed, Mac68k };
494
495	// #pragma pack info constructor
496	AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
497	: PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
498	assert(Num == PackNumber && "The pack number has been truncated.")((void)0);
499	}
500
501	// #pragma align info constructor
502	AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
503	: PackAttr(false), AlignMode(M),
504	PackNumber(M == Packed ? 1 : UninitPackVal), XLStack(IsXL) {}
505
506	explicit AlignPackInfo(bool IsXL) : AlignPackInfo(Native, IsXL) {}
507
508	AlignPackInfo() : AlignPackInfo(Native, false) {}
509
510	// When a AlignPackInfo itself cannot be used, this returns an 32-bit
511	// integer encoding for it. This should only be passed to
512	// AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
513	static uint32_t getRawEncoding(const AlignPackInfo &Info) {
514	std::uint32_t Encoding{};
515	if (Info.IsXLStack())
516	Encoding \|= IsXLMask;
517
518	Encoding \|= static_cast<uint32_t>(Info.getAlignMode()) << 1;
519
520	if (Info.IsPackAttr())
521	Encoding \|= PackAttrMask;
522
523	Encoding \|= static_cast<uint32_t>(Info.getPackNumber()) << 4;
524
525	return Encoding;
526	}
527
528	static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
529	bool IsXL = static_cast<bool>(Encoding & IsXLMask);
530	AlignPackInfo::Mode M =
531	static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> 1);
532	int PackNumber = (Encoding & PackNumMask) >> 4;
533
534	if (Encoding & PackAttrMask)
535	return AlignPackInfo(M, PackNumber, IsXL);
536
537	return AlignPackInfo(M, IsXL);
538	}
539
540	bool IsPackAttr() const { return PackAttr; }
541
542	bool IsAlignAttr() const { return !PackAttr; }
543
544	Mode getAlignMode() const { return AlignMode; }
545
546	unsigned getPackNumber() const { return PackNumber; }
547
548	bool IsPackSet() const {
549	// #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
550	// attriute on a decl.
551	return PackNumber != UninitPackVal && PackNumber != 0;
552	}
553
554	bool IsXLStack() const { return XLStack; }
555
556	bool operator==(const AlignPackInfo &Info) const {
557	return std::tie(AlignMode, PackNumber, PackAttr, XLStack) ==
558	std::tie(Info.AlignMode, Info.PackNumber, Info.PackAttr,
559	Info.XLStack);
560	}
561
562	bool operator!=(const AlignPackInfo &Info) const {
563	return !(*this == Info);
564	}
565
566	private:
567	/// \brief True if this is a pragma pack attribute,
568	/// not a pragma align attribute.
569	bool PackAttr;
570
571	/// \brief The alignment mode that is in effect.
572	Mode AlignMode;
573
574	/// \brief The pack number of the stack.
575	unsigned char PackNumber;
576
577	/// \brief True if it is a XL #pragma align/pack stack.
578	bool XLStack;
579
580	/// \brief Uninitialized pack value.
581	static constexpr unsigned char UninitPackVal = -1;
582
583	// Masks to encode and decode an AlignPackInfo.
584	static constexpr uint32_t IsXLMask{0x0000'0001};
585	static constexpr uint32_t AlignModeMask{0x0000'0006};
586	static constexpr uint32_t PackAttrMask{0x00000'0008};
587	static constexpr uint32_t PackNumMask{0x0000'01F0};
588	};
589
590	template<typename ValueType>
591	struct PragmaStack {
592	struct Slot {
593	llvm::StringRef StackSlotLabel;
594	ValueType Value;
595	SourceLocation PragmaLocation;
596	SourceLocation PragmaPushLocation;
597	Slot(llvm::StringRef StackSlotLabel, ValueType Value,
598	SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
599	: StackSlotLabel(StackSlotLabel), Value(Value),
600	PragmaLocation(PragmaLocation),
601	PragmaPushLocation(PragmaPushLocation) {}
602	};
603
604	void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
605	llvm::StringRef StackSlotLabel, ValueType Value) {
606	if (Action == PSK_Reset) {
607	CurrentValue = DefaultValue;
608	CurrentPragmaLocation = PragmaLocation;
609	return;
610	}
611	if (Action & PSK_Push)
612	Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
613	PragmaLocation);
614	else if (Action & PSK_Pop) {
615	if (!StackSlotLabel.empty()) {
616	// If we've got a label, try to find it and jump there.
617	auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
618	return x.StackSlotLabel == StackSlotLabel;
619	});
620	// If we found the label so pop from there.
621	if (I != Stack.rend()) {
622	CurrentValue = I->Value;
623	CurrentPragmaLocation = I->PragmaLocation;
624	Stack.erase(std::prev(I.base()), Stack.end());
625	}
626	} else if (!Stack.empty()) {
627	// We do not have a label, just pop the last entry.
628	CurrentValue = Stack.back().Value;
629	CurrentPragmaLocation = Stack.back().PragmaLocation;
630	Stack.pop_back();
631	}
632	}
633	if (Action & PSK_Set) {
634	CurrentValue = Value;
635	CurrentPragmaLocation = PragmaLocation;
636	}
637	}
638
639	// MSVC seems to add artificial slots to #pragma stacks on entering a C++
640	// method body to restore the stacks on exit, so it works like this:
641	//
642	// struct S {
643	// #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
644	// void Method {}
645	// #pragma <name>(pop, InternalPragmaSlot)
646	// };
647	//
648	// It works even with #pragma vtordisp, although MSVC doesn't support
649	// #pragma vtordisp(push [, id], n)
650	// syntax.
651	//
652	// Push / pop a named sentinel slot.
653	void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
654	assert((Action == PSK_Push \|\| Action == PSK_Pop) &&((void)0)
655	"Can only push / pop #pragma stack sentinels!")((void)0);
656	Act(CurrentPragmaLocation, Action, Label, CurrentValue);
657	}
658
659	// Constructors.
660	explicit PragmaStack(const ValueType &Default)
661	: DefaultValue(Default), CurrentValue(Default) {}
662
663	bool hasValue() const { return CurrentValue != DefaultValue; }
664
665	SmallVector<Slot, 2> Stack;
666	ValueType DefaultValue; // Value used for PSK_Reset action.
667	ValueType CurrentValue;
668	SourceLocation CurrentPragmaLocation;
669	};
670	// FIXME: We should serialize / deserialize these if they occur in a PCH (but
671	// we shouldn't do so if they're in a module).
672
673	/// Whether to insert vtordisps prior to virtual bases in the Microsoft
674	/// C++ ABI. Possible values are 0, 1, and 2, which mean:
675	///
676	/// 0: Suppress all vtordisps
677	/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
678	/// structors
679	/// 2: Always insert vtordisps to support RTTI on partially constructed
680	/// objects
681	PragmaStack<MSVtorDispMode> VtorDispStack;
682	PragmaStack<AlignPackInfo> AlignPackStack;
683	// The current #pragma align/pack values and locations at each #include.
684	struct AlignPackIncludeState {
685	AlignPackInfo CurrentValue;
686	SourceLocation CurrentPragmaLocation;
687	bool HasNonDefaultValue, ShouldWarnOnInclude;
688	};
689	SmallVector<AlignPackIncludeState, 8> AlignPackIncludeStack;
690	// Segment #pragmas.
691	PragmaStack<StringLiteral *> DataSegStack;
692	PragmaStack<StringLiteral *> BSSSegStack;
693	PragmaStack<StringLiteral *> ConstSegStack;
694	PragmaStack<StringLiteral *> CodeSegStack;
695
696	// This stack tracks the current state of Sema.CurFPFeatures.
697	PragmaStack<FPOptionsOverride> FpPragmaStack;
698	FPOptionsOverride CurFPFeatureOverrides() {
699	FPOptionsOverride result;
700	if (!FpPragmaStack.hasValue()) {
701	result = FPOptionsOverride();
702	} else {
703	result = FpPragmaStack.CurrentValue;
704	}
705	return result;
706	}
707
708	// RAII object to push / pop sentinel slots for all MS #pragma stacks.
709	// Actions should be performed only if we enter / exit a C++ method body.
710	class PragmaStackSentinelRAII {
711	public:
712	PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
713	~PragmaStackSentinelRAII();
714
715	private:
716	Sema &S;
717	StringRef SlotLabel;
718	bool ShouldAct;
719	};
720
721	/// A mapping that describes the nullability we've seen in each header file.
722	FileNullabilityMap NullabilityMap;
723
724	/// Last section used with #pragma init_seg.
725	StringLiteral *CurInitSeg;
726	SourceLocation CurInitSegLoc;
727
728	/// VisContext - Manages the stack for \#pragma GCC visibility.
729	void VisContext; // Really a "PragmaVisStack"
730
731	/// This an attribute introduced by \#pragma clang attribute.
732	struct PragmaAttributeEntry {
733	SourceLocation Loc;
734	ParsedAttr *Attribute;
735	SmallVector<attr::SubjectMatchRule, 4> MatchRules;
736	bool IsUsed;
737	};
738
739	/// A push'd group of PragmaAttributeEntries.
740	struct PragmaAttributeGroup {
741	/// The location of the push attribute.
742	SourceLocation Loc;
743	/// The namespace of this push group.
744	const IdentifierInfo *Namespace;
745	SmallVector<PragmaAttributeEntry, 2> Entries;
746	};
747
748	SmallVector<PragmaAttributeGroup, 2> PragmaAttributeStack;
749
750	/// The declaration that is currently receiving an attribute from the
751	/// #pragma attribute stack.
752	const Decl *PragmaAttributeCurrentTargetDecl;
753
754	/// This represents the last location of a "#pragma clang optimize off"
755	/// directive if such a directive has not been closed by an "on" yet. If
756	/// optimizations are currently "on", this is set to an invalid location.
757	SourceLocation OptimizeOffPragmaLocation;
758
759	/// Flag indicating if Sema is building a recovery call expression.
760	///
761	/// This flag is used to avoid building recovery call expressions
762	/// if Sema is already doing so, which would cause infinite recursions.
763	bool IsBuildingRecoveryCallExpr;
764
765	/// Used to control the generation of ExprWithCleanups.
766	CleanupInfo Cleanup;
767
768	/// ExprCleanupObjects - This is the stack of objects requiring
769	/// cleanup that are created by the current full expression.
770	SmallVector<ExprWithCleanups::CleanupObject, 8> ExprCleanupObjects;
771
772	/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
773	/// to a variable (constant) that may or may not be odr-used in this Expr, and
774	/// we won't know until all lvalue-to-rvalue and discarded value conversions
775	/// have been applied to all subexpressions of the enclosing full expression.
776	/// This is cleared at the end of each full expression.
777	using MaybeODRUseExprSet = llvm::SetVector<Expr , SmallVector<Expr , 4>,
778	llvm::SmallPtrSet<Expr *, 4>>;
779	MaybeODRUseExprSet MaybeODRUseExprs;
780
781	std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;
782
783	/// Stack containing information about each of the nested
784	/// function, block, and method scopes that are currently active.
785	SmallVector<sema::FunctionScopeInfo *, 4> FunctionScopes;
786
787	/// The index of the first FunctionScope that corresponds to the current
788	/// context.
789	unsigned FunctionScopesStart = 0;
790
791	ArrayRef<sema::FunctionScopeInfo*> getFunctionScopes() const {
792	return llvm::makeArrayRef(FunctionScopes.begin() + FunctionScopesStart,
793	FunctionScopes.end());
794	}
795
796	/// Stack containing information needed when in C++2a an 'auto' is encountered
797	/// in a function declaration parameter type specifier in order to invent a
798	/// corresponding template parameter in the enclosing abbreviated function
799	/// template. This information is also present in LambdaScopeInfo, stored in
800	/// the FunctionScopes stack.
801	SmallVector<InventedTemplateParameterInfo, 4> InventedParameterInfos;
802
803	/// The index of the first InventedParameterInfo that refers to the current
804	/// context.
805	unsigned InventedParameterInfosStart = 0;
806
807	ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
808	return llvm::makeArrayRef(InventedParameterInfos.begin() +
809	InventedParameterInfosStart,
810	InventedParameterInfos.end());
811	}
812
813	typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
814	&ExternalSemaSource::ReadExtVectorDecls, 2, 2>
815	ExtVectorDeclsType;
816
817	/// ExtVectorDecls - This is a list all the extended vector types. This allows
818	/// us to associate a raw vector type with one of the ext_vector type names.
819	/// This is only necessary for issuing pretty diagnostics.
820	ExtVectorDeclsType ExtVectorDecls;
821
822	/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
823	std::unique_ptr<CXXFieldCollector> FieldCollector;
824
825	typedef llvm::SmallSetVector<NamedDecl *, 16> NamedDeclSetType;
826
827	/// Set containing all declared private fields that are not used.
828	NamedDeclSetType UnusedPrivateFields;
829
830	/// Set containing all typedefs that are likely unused.
831	llvm::SmallSetVector<const TypedefNameDecl *, 4>
832	UnusedLocalTypedefNameCandidates;
833
834	/// Delete-expressions to be analyzed at the end of translation unit
835	///
836	/// This list contains class members, and locations of delete-expressions
837	/// that could not be proven as to whether they mismatch with new-expression
838	/// used in initializer of the field.
839	typedef std::pair<SourceLocation, bool> DeleteExprLoc;
840	typedef llvm::SmallVector<DeleteExprLoc, 4> DeleteLocs;
841	llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;
842
843	typedef llvm::SmallPtrSet<const CXXRecordDecl*, 8> RecordDeclSetTy;
844
845	/// PureVirtualClassDiagSet - a set of class declarations which we have
846	/// emitted a list of pure virtual functions. Used to prevent emitting the
847	/// same list more than once.
848	std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;
849
850	/// ParsingInitForAutoVars - a set of declarations with auto types for which
851	/// we are currently parsing the initializer.
852	llvm::SmallPtrSet<const Decl*, 4> ParsingInitForAutoVars;
853
854	/// Look for a locally scoped extern "C" declaration by the given name.
855	NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);
856
857	typedef LazyVector<VarDecl *, ExternalSemaSource,
858	&ExternalSemaSource::ReadTentativeDefinitions, 2, 2>
859	TentativeDefinitionsType;
860
861	/// All the tentative definitions encountered in the TU.
862	TentativeDefinitionsType TentativeDefinitions;
863
864	/// All the external declarations encoutered and used in the TU.
865	SmallVector<VarDecl *, 4> ExternalDeclarations;
866
867	typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
868	&ExternalSemaSource::ReadUnusedFileScopedDecls, 2, 2>
869	UnusedFileScopedDeclsType;
870
871	/// The set of file scoped decls seen so far that have not been used
872	/// and must warn if not used. Only contains the first declaration.
873	UnusedFileScopedDeclsType UnusedFileScopedDecls;
874
875	typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
876	&ExternalSemaSource::ReadDelegatingConstructors, 2, 2>
877	DelegatingCtorDeclsType;
878
879	/// All the delegating constructors seen so far in the file, used for
880	/// cycle detection at the end of the TU.
881	DelegatingCtorDeclsType DelegatingCtorDecls;
882
883	/// All the overriding functions seen during a class definition
884	/// that had their exception spec checks delayed, plus the overridden
885	/// function.
886	SmallVector<std::pair<const CXXMethodDecl, const CXXMethodDecl>, 2>
887	DelayedOverridingExceptionSpecChecks;
888
889	/// All the function redeclarations seen during a class definition that had
890	/// their exception spec checks delayed, plus the prior declaration they
891	/// should be checked against. Except during error recovery, the new decl
892	/// should always be a friend declaration, as that's the only valid way to
893	/// redeclare a special member before its class is complete.
894	SmallVector<std::pair<FunctionDecl, FunctionDecl>, 2>
895	DelayedEquivalentExceptionSpecChecks;
896
897	typedef llvm::MapVector<const FunctionDecl *,
898	std::unique_ptr<LateParsedTemplate>>
899	LateParsedTemplateMapT;
900	LateParsedTemplateMapT LateParsedTemplateMap;
901
902	/// Callback to the parser to parse templated functions when needed.
903	typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
904	typedef void LateTemplateParserCleanupCB(void *P);
905	LateTemplateParserCB *LateTemplateParser;
906	LateTemplateParserCleanupCB *LateTemplateParserCleanup;
907	void *OpaqueParser;
908
909	void SetLateTemplateParser(LateTemplateParserCB *LTP,
910	LateTemplateParserCleanupCB *LTPCleanup,
911	void *P) {
912	LateTemplateParser = LTP;
913	LateTemplateParserCleanup = LTPCleanup;
914	OpaqueParser = P;
915	}
916
917	// Does the work necessary to deal with a SYCL kernel lambda. At the moment,
918	// this just marks the list of lambdas required to name the kernel.
919	void AddSYCLKernelLambda(const FunctionDecl *FD);
920
921	class DelayedDiagnostics;
922
923	class DelayedDiagnosticsState {
924	sema::DelayedDiagnosticPool *SavedPool;
925	friend class Sema::DelayedDiagnostics;
926	};
927	typedef DelayedDiagnosticsState ParsingDeclState;
928	typedef DelayedDiagnosticsState ProcessingContextState;
929
930	/// A class which encapsulates the logic for delaying diagnostics
931	/// during parsing and other processing.
932	class DelayedDiagnostics {
933	/// The current pool of diagnostics into which delayed
934	/// diagnostics should go.
935	sema::DelayedDiagnosticPool *CurPool;
936
937	public:
938	DelayedDiagnostics() : CurPool(nullptr) {}
939
940	/// Adds a delayed diagnostic.
941	void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h
942
943	/// Determines whether diagnostics should be delayed.
944	bool shouldDelayDiagnostics() { return CurPool != nullptr; }
945
946	/// Returns the current delayed-diagnostics pool.
947	sema::DelayedDiagnosticPool *getCurrentPool() const {
948	return CurPool;
949	}
950
951	/// Enter a new scope. Access and deprecation diagnostics will be
952	/// collected in this pool.
953	DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
954	DelayedDiagnosticsState state;
955	state.SavedPool = CurPool;
956	CurPool = &pool;
957	return state;
958	}
959
960	/// Leave a delayed-diagnostic state that was previously pushed.
961	/// Do not emit any of the diagnostics. This is performed as part
962	/// of the bookkeeping of popping a pool "properly".
963	void popWithoutEmitting(DelayedDiagnosticsState state) {
964	CurPool = state.SavedPool;
965	}
966
967	/// Enter a new scope where access and deprecation diagnostics are
968	/// not delayed.
969	DelayedDiagnosticsState pushUndelayed() {
970	DelayedDiagnosticsState state;
971	state.SavedPool = CurPool;
972	CurPool = nullptr;
973	return state;
974	}
975
976	/// Undo a previous pushUndelayed().
977	void popUndelayed(DelayedDiagnosticsState state) {
978	assert(CurPool == nullptr)((void)0);
979	CurPool = state.SavedPool;
980	}
981	} DelayedDiagnostics;
982
983	/// A RAII object to temporarily push a declaration context.
984	class ContextRAII {
985	private:
986	Sema &S;
987	DeclContext *SavedContext;
988	ProcessingContextState SavedContextState;
989	QualType SavedCXXThisTypeOverride;
990	unsigned SavedFunctionScopesStart;
991	unsigned SavedInventedParameterInfosStart;
992
993	public:
994	ContextRAII(Sema &S, DeclContext *ContextToPush, bool NewThisContext = true)
995	: S(S), SavedContext(S.CurContext),
996	SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
997	SavedCXXThisTypeOverride(S.CXXThisTypeOverride),
998	SavedFunctionScopesStart(S.FunctionScopesStart),
999	SavedInventedParameterInfosStart(S.InventedParameterInfosStart)
1000	{
1001	assert(ContextToPush && "pushing null context")((void)0);
1002	S.CurContext = ContextToPush;
1003	if (NewThisContext)
1004	S.CXXThisTypeOverride = QualType();
1005	// Any saved FunctionScopes do not refer to this context.
1006	S.FunctionScopesStart = S.FunctionScopes.size();
1007	S.InventedParameterInfosStart = S.InventedParameterInfos.size();
1008	}
1009
1010	void pop() {
1011	if (!SavedContext) return;
1012	S.CurContext = SavedContext;
1013	S.DelayedDiagnostics.popUndelayed(SavedContextState);
1014	S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
1015	S.FunctionScopesStart = SavedFunctionScopesStart;
1016	S.InventedParameterInfosStart = SavedInventedParameterInfosStart;
1017	SavedContext = nullptr;
1018	}
1019
1020	~ContextRAII() {
1021	pop();
1022	}
1023	};
1024
1025	/// Whether the AST is currently being rebuilt to correct immediate
1026	/// invocations. Immediate invocation candidates and references to consteval
1027	/// functions aren't tracked when this is set.
1028	bool RebuildingImmediateInvocation = false;
1029
1030	/// Used to change context to isConstantEvaluated without pushing a heavy
1031	/// ExpressionEvaluationContextRecord object.
1032	bool isConstantEvaluatedOverride;
1033
1034	bool isConstantEvaluated() {
1035	return ExprEvalContexts.back().isConstantEvaluated() \|\|
1036	isConstantEvaluatedOverride;
1037	}
1038
1039	/// RAII object to handle the state changes required to synthesize
1040	/// a function body.
1041	class SynthesizedFunctionScope {
1042	Sema &S;
1043	Sema::ContextRAII SavedContext;
1044	bool PushedCodeSynthesisContext = false;
1045
1046	public:
1047	SynthesizedFunctionScope(Sema &S, DeclContext *DC)
1048	: S(S), SavedContext(S, DC) {
1049	S.PushFunctionScope();
1050	S.PushExpressionEvaluationContext(
1051	Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
1052	if (auto *FD = dyn_cast<FunctionDecl>(DC))
1053	FD->setWillHaveBody(true);
1054	else
1055	assert(isa<ObjCMethodDecl>(DC))((void)0);
1056	}
1057
1058	void addContextNote(SourceLocation UseLoc) {
1059	assert(!PushedCodeSynthesisContext)((void)0);
1060
1061	Sema::CodeSynthesisContext Ctx;
1062	Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
1063	Ctx.PointOfInstantiation = UseLoc;
1064	Ctx.Entity = cast<Decl>(S.CurContext);
1065	S.pushCodeSynthesisContext(Ctx);
1066
1067	PushedCodeSynthesisContext = true;
1068	}
1069
1070	~SynthesizedFunctionScope() {
1071	if (PushedCodeSynthesisContext)
1072	S.popCodeSynthesisContext();
1073	if (auto *FD = dyn_cast<FunctionDecl>(S.CurContext))
1074	FD->setWillHaveBody(false);
1075	S.PopExpressionEvaluationContext();
1076	S.PopFunctionScopeInfo();
1077	}
1078	};
1079
1080	/// WeakUndeclaredIdentifiers - Identifiers contained in
1081	/// \#pragma weak before declared. rare. may alias another
1082	/// identifier, declared or undeclared
1083	llvm::MapVector<IdentifierInfo *, WeakInfo> WeakUndeclaredIdentifiers;
1084
1085	/// ExtnameUndeclaredIdentifiers - Identifiers contained in
1086	/// \#pragma redefine_extname before declared. Used in Solaris system headers
1087	/// to define functions that occur in multiple standards to call the version
1088	/// in the currently selected standard.
1089	llvm::DenseMap<IdentifierInfo,AsmLabelAttr> ExtnameUndeclaredIdentifiers;
1090
1091
1092	/// Load weak undeclared identifiers from the external source.
1093	void LoadExternalWeakUndeclaredIdentifiers();
1094
1095	/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
1096	/// \#pragma weak during processing of other Decls.
1097	/// I couldn't figure out a clean way to generate these in-line, so
1098	/// we store them here and handle separately -- which is a hack.
1099	/// It would be best to refactor this.
1100	SmallVector<Decl*,2> WeakTopLevelDecl;
1101
1102	IdentifierResolver IdResolver;
1103
1104	/// Translation Unit Scope - useful to Objective-C actions that need
1105	/// to lookup file scope declarations in the "ordinary" C decl namespace.
1106	/// For example, user-defined classes, built-in "id" type, etc.
1107	Scope *TUScope;
1108
1109	/// The C++ "std" namespace, where the standard library resides.
1110	LazyDeclPtr StdNamespace;
1111
1112	/// The C++ "std::bad_alloc" class, which is defined by the C++
1113	/// standard library.
1114	LazyDeclPtr StdBadAlloc;
1115
1116	/// The C++ "std::align_val_t" enum class, which is defined by the C++
1117	/// standard library.
1118	LazyDeclPtr StdAlignValT;
1119
1120	/// The C++ "std::experimental" namespace, where the experimental parts
1121	/// of the standard library resides.
1122	NamespaceDecl *StdExperimentalNamespaceCache;
1123
1124	/// The C++ "std::initializer_list" template, which is defined in
1125	/// \<initializer_list>.
1126	ClassTemplateDecl *StdInitializerList;
1127
1128	/// The C++ "std::coroutine_traits" template, which is defined in
1129	/// \<coroutine_traits>
1130	ClassTemplateDecl *StdCoroutineTraitsCache;
1131
1132	/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
1133	RecordDecl *CXXTypeInfoDecl;
1134
1135	/// The MSVC "_GUID" struct, which is defined in MSVC header files.
1136	RecordDecl *MSVCGuidDecl;
1137
1138	/// Caches identifiers/selectors for NSFoundation APIs.
1139	std::unique_ptr<NSAPI> NSAPIObj;
1140
1141	/// The declaration of the Objective-C NSNumber class.
1142	ObjCInterfaceDecl *NSNumberDecl;
1143
1144	/// The declaration of the Objective-C NSValue class.
1145	ObjCInterfaceDecl *NSValueDecl;
1146
1147	/// Pointer to NSNumber type (NSNumber *).
1148	QualType NSNumberPointer;
1149
1150	/// Pointer to NSValue type (NSValue *).
1151	QualType NSValuePointer;
1152
1153	/// The Objective-C NSNumber methods used to create NSNumber literals.
1154	ObjCMethodDecl *NSNumberLiteralMethods[NSAPI::NumNSNumberLiteralMethods];
1155
1156	/// The declaration of the Objective-C NSString class.
1157	ObjCInterfaceDecl *NSStringDecl;
1158
1159	/// Pointer to NSString type (NSString *).
1160	QualType NSStringPointer;
1161
1162	/// The declaration of the stringWithUTF8String: method.
1163	ObjCMethodDecl *StringWithUTF8StringMethod;
1164
1165	/// The declaration of the valueWithBytes:objCType: method.
1166	ObjCMethodDecl *ValueWithBytesObjCTypeMethod;
1167
1168	/// The declaration of the Objective-C NSArray class.
1169	ObjCInterfaceDecl *NSArrayDecl;
1170
1171	/// The declaration of the arrayWithObjects:count: method.
1172	ObjCMethodDecl *ArrayWithObjectsMethod;
1173
1174	/// The declaration of the Objective-C NSDictionary class.
1175	ObjCInterfaceDecl *NSDictionaryDecl;
1176
1177	/// The declaration of the dictionaryWithObjects:forKeys:count: method.
1178	ObjCMethodDecl *DictionaryWithObjectsMethod;
1179
1180	/// id<NSCopying> type.
1181	QualType QIDNSCopying;
1182
1183	/// will hold 'respondsToSelector:'
1184	Selector RespondsToSelectorSel;
1185
1186	/// A flag to remember whether the implicit forms of operator new and delete
1187	/// have been declared.
1188	bool GlobalNewDeleteDeclared;
1189
1190	/// Describes how the expressions currently being parsed are
1191	/// evaluated at run-time, if at all.
1192	enum class ExpressionEvaluationContext {
1193	/// The current expression and its subexpressions occur within an
1194	/// unevaluated operand (C++11 [expr]p7), such as the subexpression of
1195	/// \c sizeof, where the type of the expression may be significant but
1196	/// no code will be generated to evaluate the value of the expression at
1197	/// run time.
1198	Unevaluated,
1199
1200	/// The current expression occurs within a braced-init-list within
1201	/// an unevaluated operand. This is mostly like a regular unevaluated
1202	/// context, except that we still instantiate constexpr functions that are
1203	/// referenced here so that we can perform narrowing checks correctly.
1204	UnevaluatedList,
1205
1206	/// The current expression occurs within a discarded statement.
1207	/// This behaves largely similarly to an unevaluated operand in preventing
1208	/// definitions from being required, but not in other ways.
1209	DiscardedStatement,
1210
1211	/// The current expression occurs within an unevaluated
1212	/// operand that unconditionally permits abstract references to
1213	/// fields, such as a SIZE operator in MS-style inline assembly.
1214	UnevaluatedAbstract,
1215
1216	/// The current context is "potentially evaluated" in C++11 terms,
1217	/// but the expression is evaluated at compile-time (like the values of
1218	/// cases in a switch statement).
1219	ConstantEvaluated,
1220
1221	/// The current expression is potentially evaluated at run time,
1222	/// which means that code may be generated to evaluate the value of the
1223	/// expression at run time.
1224	PotentiallyEvaluated,
1225
1226	/// The current expression is potentially evaluated, but any
1227	/// declarations referenced inside that expression are only used if
1228	/// in fact the current expression is used.
1229	///
1230	/// This value is used when parsing default function arguments, for which
1231	/// we would like to provide diagnostics (e.g., passing non-POD arguments
1232	/// through varargs) but do not want to mark declarations as "referenced"
1233	/// until the default argument is used.
1234	PotentiallyEvaluatedIfUsed
1235	};
1236
1237	using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, 1>;
1238
1239	/// Data structure used to record current or nested
1240	/// expression evaluation contexts.
1241	struct ExpressionEvaluationContextRecord {
1242	/// The expression evaluation context.
1243	ExpressionEvaluationContext Context;
1244
1245	/// Whether the enclosing context needed a cleanup.
1246	CleanupInfo ParentCleanup;
1247
1248	/// The number of active cleanup objects when we entered
1249	/// this expression evaluation context.
1250	unsigned NumCleanupObjects;
1251
1252	/// The number of typos encountered during this expression evaluation
1253	/// context (i.e. the number of TypoExprs created).
1254	unsigned NumTypos;
1255
1256	MaybeODRUseExprSet SavedMaybeODRUseExprs;
1257
1258	/// The lambdas that are present within this context, if it
1259	/// is indeed an unevaluated context.
1260	SmallVector<LambdaExpr *, 2> Lambdas;
1261
1262	/// The declaration that provides context for lambda expressions
1263	/// and block literals if the normal declaration context does not
1264	/// suffice, e.g., in a default function argument.
1265	Decl *ManglingContextDecl;
1266
1267	/// If we are processing a decltype type, a set of call expressions
1268	/// for which we have deferred checking the completeness of the return type.
1269	SmallVector<CallExpr *, 8> DelayedDecltypeCalls;
1270
1271	/// If we are processing a decltype type, a set of temporary binding
1272	/// expressions for which we have deferred checking the destructor.
1273	SmallVector<CXXBindTemporaryExpr *, 8> DelayedDecltypeBinds;
1274
1275	llvm::SmallPtrSet<const Expr *, 8> PossibleDerefs;
1276
1277	/// Expressions appearing as the LHS of a volatile assignment in this
1278	/// context. We produce a warning for these when popping the context if
1279	/// they are not discarded-value expressions nor unevaluated operands.
1280	SmallVector<Expr*, 2> VolatileAssignmentLHSs;
1281
1282	/// Set of candidates for starting an immediate invocation.
1283	llvm::SmallVector<ImmediateInvocationCandidate, 4> ImmediateInvocationCandidates;
1284
1285	/// Set of DeclRefExprs referencing a consteval function when used in a
1286	/// context not already known to be immediately invoked.
1287	llvm::SmallPtrSet<DeclRefExpr *, 4> ReferenceToConsteval;
1288
1289	/// \brief Describes whether we are in an expression constext which we have
1290	/// to handle differently.
1291	enum ExpressionKind {
1292	EK_Decltype, EK_TemplateArgument, EK_Other
1293	} ExprContext;
1294
1295	ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
1296	unsigned NumCleanupObjects,
1297	CleanupInfo ParentCleanup,
1298	Decl *ManglingContextDecl,
1299	ExpressionKind ExprContext)
1300	: Context(Context), ParentCleanup(ParentCleanup),
1301	NumCleanupObjects(NumCleanupObjects), NumTypos(0),
1302	ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext) {}
1303
1304	bool isUnevaluated() const {
1305	return Context == ExpressionEvaluationContext::Unevaluated \|\|
1306	Context == ExpressionEvaluationContext::UnevaluatedAbstract \|\|
1307	Context == ExpressionEvaluationContext::UnevaluatedList;
1308	}
1309	bool isConstantEvaluated() const {
1310	return Context == ExpressionEvaluationContext::ConstantEvaluated;
1311	}
1312	};
1313
1314	/// A stack of expression evaluation contexts.
1315	SmallVector<ExpressionEvaluationContextRecord, 8> ExprEvalContexts;
1316
1317	/// Emit a warning for all pending noderef expressions that we recorded.
1318	void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);
1319
1320	/// Compute the mangling number context for a lambda expression or
1321	/// block literal. Also return the extra mangling decl if any.
1322	///
1323	/// \param DC - The DeclContext containing the lambda expression or
1324	/// block literal.
1325	std::tuple<MangleNumberingContext , Decl >
1326	getCurrentMangleNumberContext(const DeclContext *DC);
1327
1328
1329	/// SpecialMemberOverloadResult - The overloading result for a special member
1330	/// function.
1331	///
1332	/// This is basically a wrapper around PointerIntPair. The lowest bits of the
1333	/// integer are used to determine whether overload resolution succeeded.
1334	class SpecialMemberOverloadResult {
1335	public:
1336	enum Kind {
1337	NoMemberOrDeleted,
1338	Ambiguous,
1339	Success
1340	};
1341
1342	private:
1343	llvm::PointerIntPair<CXXMethodDecl*, 2> Pair;
1344
1345	public:
1346	SpecialMemberOverloadResult() : Pair() {}
1347	SpecialMemberOverloadResult(CXXMethodDecl *MD)
1348	: Pair(MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}
1349
1350	CXXMethodDecl *getMethod() const { return Pair.getPointer(); }
1351	void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }
1352
1353	Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
1354	void setKind(Kind K) { Pair.setInt(K); }
1355	};
1356
1357	class SpecialMemberOverloadResultEntry
1358	: public llvm::FastFoldingSetNode,
1359	public SpecialMemberOverloadResult {
1360	public:
1361	SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
1362	: FastFoldingSetNode(ID)
1363	{}
1364	};
1365
1366	/// A cache of special member function overload resolution results
1367	/// for C++ records.
1368	llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;
1369
1370	/// A cache of the flags available in enumerations with the flag_bits
1371	/// attribute.
1372	mutable llvm::DenseMap<const EnumDecl*, llvm::APInt> FlagBitsCache;
1373
1374	/// The kind of translation unit we are processing.
1375	///
1376	/// When we're processing a complete translation unit, Sema will perform
1377	/// end-of-translation-unit semantic tasks (such as creating
1378	/// initializers for tentative definitions in C) once parsing has
1379	/// completed. Modules and precompiled headers perform different kinds of
1380	/// checks.
1381	const TranslationUnitKind TUKind;
1382
1383	llvm::BumpPtrAllocator BumpAlloc;
1384
1385	/// The number of SFINAE diagnostics that have been trapped.
1386	unsigned NumSFINAEErrors;
1387
1388	typedef llvm::DenseMap<ParmVarDecl , llvm::TinyPtrVector<ParmVarDecl >>
1389	UnparsedDefaultArgInstantiationsMap;
1390
1391	/// A mapping from parameters with unparsed default arguments to the
1392	/// set of instantiations of each parameter.
1393	///
1394	/// This mapping is a temporary data structure used when parsing
1395	/// nested class templates or nested classes of class templates,
1396	/// where we might end up instantiating an inner class before the
1397	/// default arguments of its methods have been parsed.
1398	UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;
1399
1400	// Contains the locations of the beginning of unparsed default
1401	// argument locations.
1402	llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;
1403
1404	/// UndefinedInternals - all the used, undefined objects which require a
1405	/// definition in this translation unit.
1406	llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;
1407
1408	/// Determine if VD, which must be a variable or function, is an external
1409	/// symbol that nonetheless can't be referenced from outside this translation
1410	/// unit because its type has no linkage and it's not extern "C".
1411	bool isExternalWithNoLinkageType(ValueDecl *VD);
1412
1413	/// Obtain a sorted list of functions that are undefined but ODR-used.
1414	void getUndefinedButUsed(
1415	SmallVectorImpl<std::pair<NamedDecl *, SourceLocation> > &Undefined);
1416
1417	/// Retrieves list of suspicious delete-expressions that will be checked at
1418	/// the end of translation unit.
1419	const llvm::MapVector<FieldDecl *, DeleteLocs> &
1420	getMismatchingDeleteExpressions() const;
1421
1422	typedef std::pair<ObjCMethodList, ObjCMethodList> GlobalMethods;
1423	typedef llvm::DenseMap<Selector, GlobalMethods> GlobalMethodPool;
1424
1425	/// Method Pool - allows efficient lookup when typechecking messages to "id".
1426	/// We need to maintain a list, since selectors can have differing signatures
1427	/// across classes. In Cocoa, this happens to be extremely uncommon (only 1%
1428	/// of selectors are "overloaded").
1429	/// At the head of the list it is recorded whether there were 0, 1, or >= 2
1430	/// methods inside categories with a particular selector.
1431	GlobalMethodPool MethodPool;
1432
1433	/// Method selectors used in a \@selector expression. Used for implementation
1434	/// of -Wselector.
1435	llvm::MapVector<Selector, SourceLocation> ReferencedSelectors;
1436
1437	/// List of SourceLocations where 'self' is implicitly retained inside a
1438	/// block.
1439	llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, 1>
1440	ImplicitlyRetainedSelfLocs;
1441
1442	/// Kinds of C++ special members.
1443	enum CXXSpecialMember {
1444	CXXDefaultConstructor,
1445	CXXCopyConstructor,
1446	CXXMoveConstructor,
1447	CXXCopyAssignment,
1448	CXXMoveAssignment,
1449	CXXDestructor,
1450	CXXInvalid
1451	};
1452
1453	typedef llvm::PointerIntPair<CXXRecordDecl *, 3, CXXSpecialMember>
1454	SpecialMemberDecl;
1455
1456	/// The C++ special members which we are currently in the process of
1457	/// declaring. If this process recursively triggers the declaration of the
1458	/// same special member, we should act as if it is not yet declared.
1459	llvm::SmallPtrSet<SpecialMemberDecl, 4> SpecialMembersBeingDeclared;
1460
1461	/// Kinds of defaulted comparison operator functions.
1462	enum class DefaultedComparisonKind : unsigned char {
1463	/// This is not a defaultable comparison operator.
1464	None,
1465	/// This is an operator== that should be implemented as a series of
1466	/// subobject comparisons.
1467	Equal,
1468	/// This is an operator<=> that should be implemented as a series of
1469	/// subobject comparisons.
1470	ThreeWay,
1471	/// This is an operator!= that should be implemented as a rewrite in terms
1472	/// of a == comparison.
1473	NotEqual,
1474	/// This is an <, <=, >, or >= that should be implemented as a rewrite in
1475	/// terms of a <=> comparison.
1476	Relational,
1477	};
1478
1479	/// The function definitions which were renamed as part of typo-correction
1480	/// to match their respective declarations. We want to keep track of them
1481	/// to ensure that we don't emit a "redefinition" error if we encounter a
1482	/// correctly named definition after the renamed definition.
1483	llvm::SmallPtrSet<const NamedDecl *, 4> TypoCorrectedFunctionDefinitions;
1484
1485	/// Stack of types that correspond to the parameter entities that are
1486	/// currently being copy-initialized. Can be empty.
1487	llvm::SmallVector<QualType, 4> CurrentParameterCopyTypes;
1488
1489	void ReadMethodPool(Selector Sel);
1490	void updateOutOfDateSelector(Selector Sel);
1491
1492	/// Private Helper predicate to check for 'self'.
1493	bool isSelfExpr(Expr *RExpr);
1494	bool isSelfExpr(Expr RExpr, const ObjCMethodDecl Method);
1495
1496	/// Cause the active diagnostic on the DiagosticsEngine to be
1497	/// emitted. This is closely coupled to the SemaDiagnosticBuilder class and
1498	/// should not be used elsewhere.
1499	void EmitCurrentDiagnostic(unsigned DiagID);
1500
1501	/// Records and restores the CurFPFeatures state on entry/exit of compound
1502	/// statements.
1503	class FPFeaturesStateRAII {
1504	public:
1505	FPFeaturesStateRAII(Sema &S) : S(S), OldFPFeaturesState(S.CurFPFeatures) {
1506	OldOverrides = S.FpPragmaStack.CurrentValue;
1507	}
1508	~FPFeaturesStateRAII() {
1509	S.CurFPFeatures = OldFPFeaturesState;
1510	S.FpPragmaStack.CurrentValue = OldOverrides;
1511	}
1512	FPOptionsOverride getOverrides() { return OldOverrides; }
1513
1514	private:
1515	Sema& S;
1516	FPOptions OldFPFeaturesState;
1517	FPOptionsOverride OldOverrides;
1518	};
1519
1520	void addImplicitTypedef(StringRef Name, QualType T);
1521
1522	bool WarnedStackExhausted = false;
1523
1524	/// Increment when we find a reference; decrement when we find an ignored
1525	/// assignment. Ultimately the value is 0 if every reference is an ignored
1526	/// assignment.
1527	llvm::DenseMap<const VarDecl *, int> RefsMinusAssignments;
1528
1529	Optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;
1530
1531	public:
1532	Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
1533	TranslationUnitKind TUKind = TU_Complete,
1534	CodeCompleteConsumer *CompletionConsumer = nullptr);
1535	~Sema();
1536
1537	/// Perform initialization that occurs after the parser has been
1538	/// initialized but before it parses anything.
1539	void Initialize();
1540
1541	/// This virtual key function only exists to limit the emission of debug info
1542	/// describing the Sema class. GCC and Clang only emit debug info for a class
1543	/// with a vtable when the vtable is emitted. Sema is final and not
1544	/// polymorphic, but the debug info size savings are so significant that it is
1545	/// worth adding a vtable just to take advantage of this optimization.
1546	virtual void anchor();
1547
1548	const LangOptions &getLangOpts() const { return LangOpts; }
1549	OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
1550	FPOptions &getCurFPFeatures() { return CurFPFeatures; }
1551
1552	DiagnosticsEngine &getDiagnostics() const { return Diags; }
1553	SourceManager &getSourceManager() const { return SourceMgr; }
1554	Preprocessor &getPreprocessor() const { return PP; }
1555	ASTContext &getASTContext() const { return Context; }
1556	ASTConsumer &getASTConsumer() const { return Consumer; }
1557	ASTMutationListener *getASTMutationListener() const;
1558	ExternalSemaSource* getExternalSource() const { return ExternalSource; }
1559	DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking(SourceLocation Loc,
1560	StringRef Platform);
1561
1562	///Registers an external source. If an external source already exists,
1563	/// creates a multiplex external source and appends to it.
1564	///
1565	///\param[in] E - A non-null external sema source.
1566	///
1567	void addExternalSource(ExternalSemaSource *E);
1568
1569	void PrintStats() const;
1570
1571	/// Warn that the stack is nearly exhausted.
1572	void warnStackExhausted(SourceLocation Loc);
1573
1574	/// Run some code with "sufficient" stack space. (Currently, at least 256K is
1575	/// guaranteed). Produces a warning if we're low on stack space and allocates
1576	/// more in that case. Use this in code that may recurse deeply (for example,
1577	/// in template instantiation) to avoid stack overflow.
1578	void runWithSufficientStackSpace(SourceLocation Loc,
1579	llvm::function_ref<void()> Fn);
1580
1581	/// Helper class that creates diagnostics with optional
1582	/// template instantiation stacks.
1583	///
1584	/// This class provides a wrapper around the basic DiagnosticBuilder
1585	/// class that emits diagnostics. ImmediateDiagBuilder is
1586	/// responsible for emitting the diagnostic (as DiagnosticBuilder
1587	/// does) and, if the diagnostic comes from inside a template
1588	/// instantiation, printing the template instantiation stack as
1589	/// well.
1590	class ImmediateDiagBuilder : public DiagnosticBuilder {
1591	Sema &SemaRef;
1592	unsigned DiagID;
1593
1594	public:
1595	ImmediateDiagBuilder(DiagnosticBuilder &DB, Sema &SemaRef, unsigned DiagID)
1596	: DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}
1597	ImmediateDiagBuilder(DiagnosticBuilder &&DB, Sema &SemaRef, unsigned DiagID)
1598	: DiagnosticBuilder(DB), SemaRef(SemaRef), DiagID(DiagID) {}
1599
1600	// This is a cunning lie. DiagnosticBuilder actually performs move
1601	// construction in its copy constructor (but due to varied uses, it's not
1602	// possible to conveniently express this as actual move construction). So
1603	// the default copy ctor here is fine, because the base class disables the
1604	// source anyway, so the user-defined ~ImmediateDiagBuilder is a safe no-op
1605	// in that case anwyay.
1606	ImmediateDiagBuilder(const ImmediateDiagBuilder &) = default;
1607
1608	~ImmediateDiagBuilder() {
1609	// If we aren't active, there is nothing to do.
1610	if (!isActive()) return;
1611
1612	// Otherwise, we need to emit the diagnostic. First clear the diagnostic
1613	// builder itself so it won't emit the diagnostic in its own destructor.
1614	//
1615	// This seems wasteful, in that as written the DiagnosticBuilder dtor will
1616	// do its own needless checks to see if the diagnostic needs to be
1617	// emitted. However, because we take care to ensure that the builder
1618	// objects never escape, a sufficiently smart compiler will be able to
1619	// eliminate that code.
1620	Clear();
1621
1622	// Dispatch to Sema to emit the diagnostic.
1623	SemaRef.EmitCurrentDiagnostic(DiagID);
1624	}
1625
1626	/// Teach operator<< to produce an object of the correct type.
1627	template <typename T>
1628	friend const ImmediateDiagBuilder &
1629	operator<<(const ImmediateDiagBuilder &Diag, const T &Value) {
1630	const DiagnosticBuilder &BaseDiag = Diag;
1631	BaseDiag << Value;
1632	return Diag;
1633	}
1634
1635	// It is necessary to limit this to rvalue reference to avoid calling this
1636	// function with a bitfield lvalue argument since non-const reference to
1637	// bitfield is not allowed.
1638	template <typename T, typename = typename std::enable_if<
1639	!std::is_lvalue_reference<T>::value>::type>
1640	const ImmediateDiagBuilder &operator<<(T &&V) const {
1641	const DiagnosticBuilder &BaseDiag = *this;
1642	BaseDiag << std::move(V);
1643	return *this;
1644	}
1645	};
1646
1647	/// A generic diagnostic builder for errors which may or may not be deferred.
1648	///
1649	/// In CUDA, there exist constructs (e.g. variable-length arrays, try/catch)
1650	/// which are not allowed to appear inside __device__ functions and are
1651	/// allowed to appear in __host__ __device__ functions only if the host+device
1652	/// function is never codegen'ed.
1653	///
1654	/// To handle this, we use the notion of "deferred diagnostics", where we
1655	/// attach a diagnostic to a FunctionDecl that's emitted iff it's codegen'ed.
1656	///
1657	/// This class lets you emit either a regular diagnostic, a deferred
1658	/// diagnostic, or no diagnostic at all, according to an argument you pass to
1659	/// its constructor, thus simplifying the process of creating these "maybe
1660	/// deferred" diagnostics.
1661	class SemaDiagnosticBuilder {
1662	public:
1663	enum Kind {
1664	/// Emit no diagnostics.
1665	K_Nop,
1666	/// Emit the diagnostic immediately (i.e., behave like Sema::Diag()).
1667	K_Immediate,
1668	/// Emit the diagnostic immediately, and, if it's a warning or error, also
1669	/// emit a call stack showing how this function can be reached by an a
1670	/// priori known-emitted function.
1671	K_ImmediateWithCallStack,
1672	/// Create a deferred diagnostic, which is emitted only if the function
1673	/// it's attached to is codegen'ed. Also emit a call stack as with
1674	/// K_ImmediateWithCallStack.
1675	K_Deferred
1676	};
1677
1678	SemaDiagnosticBuilder(Kind K, SourceLocation Loc, unsigned DiagID,
1679	FunctionDecl *Fn, Sema &S);
1680	SemaDiagnosticBuilder(SemaDiagnosticBuilder &&D);
1681	SemaDiagnosticBuilder(const SemaDiagnosticBuilder &) = default;
1682	~SemaDiagnosticBuilder();
1683
1684	bool isImmediate() const { return ImmediateDiag.hasValue(); }
1685
1686	/// Convertible to bool: True if we immediately emitted an error, false if
1687	/// we didn't emit an error or we created a deferred error.
1688	///
1689	/// Example usage:
1690	///
1691	/// if (SemaDiagnosticBuilder(...) << foo << bar)
1692	/// return ExprError();
1693	///
1694	/// But see CUDADiagIfDeviceCode() and CUDADiagIfHostCode() -- you probably
1695	/// want to use these instead of creating a SemaDiagnosticBuilder yourself.
1696	operator bool() const { return isImmediate(); }
1697
1698	template <typename T>
1699	friend const SemaDiagnosticBuilder &
1700	operator<<(const SemaDiagnosticBuilder &Diag, const T &Value) {
1701	if (Diag.ImmediateDiag.hasValue())
1702	*Diag.ImmediateDiag << Value;
1703	else if (Diag.PartialDiagId.hasValue())
1704	Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second
1705	<< Value;
1706	return Diag;
1707	}
1708
1709	// It is necessary to limit this to rvalue reference to avoid calling this
1710	// function with a bitfield lvalue argument since non-const reference to
1711	// bitfield is not allowed.
1712	template <typename T, typename = typename std::enable_if<
1713	!std::is_lvalue_reference<T>::value>::type>
1714	const SemaDiagnosticBuilder &operator<<(T &&V) const {
1715	if (ImmediateDiag.hasValue())
1716	*ImmediateDiag << std::move(V);
1717	else if (PartialDiagId.hasValue())
1718	S.DeviceDeferredDiags[Fn][*PartialDiagId].second << std::move(V);
1719	return *this;
1720	}
1721
1722	friend const SemaDiagnosticBuilder &
1723	operator<<(const SemaDiagnosticBuilder &Diag, const PartialDiagnostic &PD) {
1724	if (Diag.ImmediateDiag.hasValue())
1725	PD.Emit(*Diag.ImmediateDiag);
1726	else if (Diag.PartialDiagId.hasValue())
1727	Diag.S.DeviceDeferredDiags[Diag.Fn][*Diag.PartialDiagId].second = PD;
1728	return Diag;
1729	}
1730
1731	void AddFixItHint(const FixItHint &Hint) const {
1732	if (ImmediateDiag.hasValue())
1733	ImmediateDiag->AddFixItHint(Hint);
1734	else if (PartialDiagId.hasValue())
1735	S.DeviceDeferredDiags[Fn][*PartialDiagId].second.AddFixItHint(Hint);
1736	}
1737
1738	friend ExprResult ExprError(const SemaDiagnosticBuilder &) {
1739	return ExprError();
1740	}
1741	friend StmtResult StmtError(const SemaDiagnosticBuilder &) {
1742	return StmtError();
1743	}
1744	operator ExprResult() const { return ExprError(); }
1745	operator StmtResult() const { return StmtError(); }
1746	operator TypeResult() const { return TypeError(); }
1747	operator DeclResult() const { return DeclResult(true); }
1748	operator MemInitResult() const { return MemInitResult(true); }
1749
1750	private:
1751	Sema &S;
1752	SourceLocation Loc;
1753	unsigned DiagID;
1754	FunctionDecl *Fn;
1755	bool ShowCallStack;
1756
1757	// Invariant: At most one of these Optionals has a value.
1758	// FIXME: Switch these to a Variant once that exists.
1759	llvm::Optional<ImmediateDiagBuilder> ImmediateDiag;
1760	llvm::Optional<unsigned> PartialDiagId;
1761	};
1762
1763	/// Is the last error level diagnostic immediate. This is used to determined
1764	/// whether the next info diagnostic should be immediate.
1765	bool IsLastErrorImmediate = true;
1766
1767	/// Emit a diagnostic.
1768	SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID,
1769	bool DeferHint = false);
1770
1771	/// Emit a partial diagnostic.
1772	SemaDiagnosticBuilder Diag(SourceLocation Loc, const PartialDiagnostic &PD,
1773	bool DeferHint = false);
1774
1775	/// Build a partial diagnostic.
1776	PartialDiagnostic PDiag(unsigned DiagID = 0); // in SemaInternal.h
1777
1778	/// Whether deferrable diagnostics should be deferred.
1779	bool DeferDiags = false;
1780
1781	/// RAII class to control scope of DeferDiags.
1782	class DeferDiagsRAII {
1783	Sema &S;
1784	bool SavedDeferDiags = false;
1785
1786	public:
1787	DeferDiagsRAII(Sema &S, bool DeferDiags)
1788	: S(S), SavedDeferDiags(S.DeferDiags) {
1789	S.DeferDiags = DeferDiags;
1790	}
1791	~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
1792	};
1793
1794	/// Whether uncompilable error has occurred. This includes error happens
1795	/// in deferred diagnostics.
1796	bool hasUncompilableErrorOccurred() const;
1797
1798	bool findMacroSpelling(SourceLocation &loc, StringRef name);
1799
1800	/// Get a string to suggest for zero-initialization of a type.
1801	std::string
1802	getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const;
1803	std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;
1804
1805	/// Calls \c Lexer::getLocForEndOfToken()
1806	SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = 0);
1807
1808	/// Retrieve the module loader associated with the preprocessor.
1809	ModuleLoader &getModuleLoader() const;
1810
1811	/// Invent a new identifier for parameters of abbreviated templates.
1812	IdentifierInfo *
1813	InventAbbreviatedTemplateParameterTypeName(IdentifierInfo *ParamName,
1814	unsigned Index);
1815
1816	void emitAndClearUnusedLocalTypedefWarnings();
1817
1818	private:
1819	/// Function or variable declarations to be checked for whether the deferred
1820	/// diagnostics should be emitted.
1821	llvm::SmallSetVector<Decl *, 4> DeclsToCheckForDeferredDiags;
1822
1823	public:
1824	// Emit all deferred diagnostics.
1825	void emitDeferredDiags();
1826
1827	enum TUFragmentKind {
1828	/// The global module fragment, between 'module;' and a module-declaration.
1829	Global,
1830	/// A normal translation unit fragment. For a non-module unit, this is the
1831	/// entire translation unit. Otherwise, it runs from the module-declaration
1832	/// to the private-module-fragment (if any) or the end of the TU (if not).
1833	Normal,
1834	/// The private module fragment, between 'module :private;' and the end of
1835	/// the translation unit.
1836	Private
1837	};
1838
1839	void ActOnStartOfTranslationUnit();
1840	void ActOnEndOfTranslationUnit();
1841	void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);
1842
1843	void CheckDelegatingCtorCycles();
1844
1845	Scope getScopeForContext(DeclContext Ctx);
1846
1847	void PushFunctionScope();
1848	void PushBlockScope(Scope BlockScope, BlockDecl Block);
1849	sema::LambdaScopeInfo *PushLambdaScope();
1850
1851	/// This is used to inform Sema what the current TemplateParameterDepth
1852	/// is during Parsing. Currently it is used to pass on the depth
1853	/// when parsing generic lambda 'auto' parameters.
1854	void RecordParsingTemplateParameterDepth(unsigned Depth);
1855
1856	void PushCapturedRegionScope(Scope RegionScope, CapturedDecl CD,
1857	RecordDecl *RD, CapturedRegionKind K,
1858	unsigned OpenMPCaptureLevel = 0);
1859
1860	/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
1861	/// time after they've been popped.
1862	class PoppedFunctionScopeDeleter {
1863	Sema *Self;
1864
1865	public:
1866	explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
1867	void operator()(sema::FunctionScopeInfo *Scope) const;
1868	};
1869
1870	using PoppedFunctionScopePtr =
1871	std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;
1872
1873	PoppedFunctionScopePtr
1874	PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy *WP = nullptr,
1875	const Decl *D = nullptr,
1876	QualType BlockType = QualType());
1877
1878	sema::FunctionScopeInfo *getCurFunction() const {
1879	return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
1880	}
1881
1882	sema::FunctionScopeInfo *getEnclosingFunction() const;
1883
1884	void setFunctionHasBranchIntoScope();
1885	void setFunctionHasBranchProtectedScope();
1886	void setFunctionHasIndirectGoto();
1887	void setFunctionHasMustTail();
1888
1889	void PushCompoundScope(bool IsStmtExpr);
1890	void PopCompoundScope();
1891
1892	sema::CompoundScopeInfo &getCurCompoundScope() const;
1893
1894	bool hasAnyUnrecoverableErrorsInThisFunction() const;
1895
1896	/// Retrieve the current block, if any.
1897	sema::BlockScopeInfo *getCurBlock();
1898
1899	/// Get the innermost lambda enclosing the current location, if any. This
1900	/// looks through intervening non-lambda scopes such as local functions and
1901	/// blocks.
1902	sema::LambdaScopeInfo *getEnclosingLambda() const;
1903
1904	/// Retrieve the current lambda scope info, if any.
1905	/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
1906	/// lambda scope info ignoring all inner capturing scopes that are not
1907	/// lambda scopes.
1908	sema::LambdaScopeInfo *
1909	getCurLambda(bool IgnoreNonLambdaCapturingScope = false);
1910
1911	/// Retrieve the current generic lambda info, if any.
1912	sema::LambdaScopeInfo *getCurGenericLambda();
1913
1914	/// Retrieve the current captured region, if any.
1915	sema::CapturedRegionScopeInfo *getCurCapturedRegion();
1916
1917	/// Retrieve the current function, if any, that should be analyzed for
1918	/// potential availability violations.
1919	sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();
1920
1921	/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
1922	SmallVectorImpl<Decl *> &WeakTopLevelDecls() { return WeakTopLevelDecl; }
1923
1924	/// Called before parsing a function declarator belonging to a function
1925	/// declaration.
1926	void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
1927	unsigned TemplateParameterDepth);
1928
1929	/// Called after parsing a function declarator belonging to a function
1930	/// declaration.
1931	void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);
1932
1933	void ActOnComment(SourceRange Comment);
1934
1935	//===--------------------------------------------------------------------===//
1936	// Type Analysis / Processing: SemaType.cpp.
1937	//
1938
1939	QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
1940	const DeclSpec *DS = nullptr);
1941	QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
1942	const DeclSpec *DS = nullptr);
1943	QualType BuildPointerType(QualType T,
1944	SourceLocation Loc, DeclarationName Entity);
1945	QualType BuildReferenceType(QualType T, bool LValueRef,
1946	SourceLocation Loc, DeclarationName Entity);
1947	QualType BuildArrayType(QualType T, ArrayType::ArraySizeModifier ASM,
1948	Expr *ArraySize, unsigned Quals,
1949	SourceRange Brackets, DeclarationName Entity);
1950	QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
1951	QualType BuildExtVectorType(QualType T, Expr *ArraySize,
1952	SourceLocation AttrLoc);
1953	QualType BuildMatrixType(QualType T, Expr NumRows, Expr NumColumns,
1954	SourceLocation AttrLoc);
1955
1956	QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
1957	SourceLocation AttrLoc);
1958
1959	/// Same as above, but constructs the AddressSpace index if not provided.
1960	QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
1961	SourceLocation AttrLoc);
1962
1963	bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);
1964
1965	bool CheckFunctionReturnType(QualType T, SourceLocation Loc);
1966
1967	/// Build a function type.
1968	///
1969	/// This routine checks the function type according to C++ rules and
1970	/// under the assumption that the result type and parameter types have
1971	/// just been instantiated from a template. It therefore duplicates
1972	/// some of the behavior of GetTypeForDeclarator, but in a much
1973	/// simpler form that is only suitable for this narrow use case.
1974	///
1975	/// \param T The return type of the function.
1976	///
1977	/// \param ParamTypes The parameter types of the function. This array
1978	/// will be modified to account for adjustments to the types of the
1979	/// function parameters.
1980	///
1981	/// \param Loc The location of the entity whose type involves this
1982	/// function type or, if there is no such entity, the location of the
1983	/// type that will have function type.
1984	///
1985	/// \param Entity The name of the entity that involves the function
1986	/// type, if known.
1987	///
1988	/// \param EPI Extra information about the function type. Usually this will
1989	/// be taken from an existing function with the same prototype.
1990	///
1991	/// \returns A suitable function type, if there are no errors. The
1992	/// unqualified type will always be a FunctionProtoType.
1993	/// Otherwise, returns a NULL type.
1994	QualType BuildFunctionType(QualType T,
1995	MutableArrayRef<QualType> ParamTypes,
1996	SourceLocation Loc, DeclarationName Entity,
1997	const FunctionProtoType::ExtProtoInfo &EPI);
1998
1999	QualType BuildMemberPointerType(QualType T, QualType Class,
2000	SourceLocation Loc,
2001	DeclarationName Entity);
2002	QualType BuildBlockPointerType(QualType T,
2003	SourceLocation Loc, DeclarationName Entity);
2004	QualType BuildParenType(QualType T);
2005	QualType BuildAtomicType(QualType T, SourceLocation Loc);
2006	QualType BuildReadPipeType(QualType T,
2007	SourceLocation Loc);
2008	QualType BuildWritePipeType(QualType T,
2009	SourceLocation Loc);
2010	QualType BuildExtIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);
2011
2012	TypeSourceInfo GetTypeForDeclarator(Declarator &D, Scope S);
2013	TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);
2014
2015	/// Package the given type and TSI into a ParsedType.
2016	ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
2017	DeclarationNameInfo GetNameForDeclarator(Declarator &D);
2018	DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
2019	static QualType GetTypeFromParser(ParsedType Ty,
2020	TypeSourceInfo **TInfo = nullptr);
2021	CanThrowResult canThrow(const Stmt *E);
2022	/// Determine whether the callee of a particular function call can throw.
2023	/// E, D and Loc are all optional.
2024	static CanThrowResult canCalleeThrow(Sema &S, const Expr E, const Decl D,
2025	SourceLocation Loc = SourceLocation());
2026	const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
2027	const FunctionProtoType *FPT);
2028	void UpdateExceptionSpec(FunctionDecl *FD,
2029	const FunctionProtoType::ExceptionSpecInfo &ESI);
2030	bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
2031	bool CheckDistantExceptionSpec(QualType T);
2032	bool CheckEquivalentExceptionSpec(FunctionDecl Old, FunctionDecl New);
2033	bool CheckEquivalentExceptionSpec(
2034	const FunctionProtoType *Old, SourceLocation OldLoc,
2035	const FunctionProtoType *New, SourceLocation NewLoc);
2036	bool CheckEquivalentExceptionSpec(
2037	const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
2038	const FunctionProtoType *Old, SourceLocation OldLoc,
2039	const FunctionProtoType *New, SourceLocation NewLoc);
2040	bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
2041	bool CheckExceptionSpecSubset(const PartialDiagnostic &DiagID,
2042	const PartialDiagnostic &NestedDiagID,
2043	const PartialDiagnostic &NoteID,
2044	const PartialDiagnostic &NoThrowDiagID,
2045	const FunctionProtoType *Superset,
2046	SourceLocation SuperLoc,
2047	const FunctionProtoType *Subset,
2048	SourceLocation SubLoc);
2049	bool CheckParamExceptionSpec(const PartialDiagnostic &NestedDiagID,
2050	const PartialDiagnostic &NoteID,
2051	const FunctionProtoType *Target,
2052	SourceLocation TargetLoc,
2053	const FunctionProtoType *Source,
2054	SourceLocation SourceLoc);
2055
2056	TypeResult ActOnTypeName(Scope *S, Declarator &D);
2057
2058	/// The parser has parsed the context-sensitive type 'instancetype'
2059	/// in an Objective-C message declaration. Return the appropriate type.
2060	ParsedType ActOnObjCInstanceType(SourceLocation Loc);
2061
2062	/// Abstract class used to diagnose incomplete types.
2063	struct TypeDiagnoser {
2064	TypeDiagnoser() {}
2065
2066	virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = 0;
2067	virtual ~TypeDiagnoser() {}
2068	};
2069
2070	static int getPrintable(int I) { return I; }
2071	static unsigned getPrintable(unsigned I) { return I; }
2072	static bool getPrintable(bool B) { return B; }
2073	static const char * getPrintable(const char *S) { return S; }
2074	static StringRef getPrintable(StringRef S) { return S; }
2075	static const std::string &getPrintable(const std::string &S) { return S; }
2076	static const IdentifierInfo getPrintable(const IdentifierInfo II) {
2077	return II;
2078	}
2079	static DeclarationName getPrintable(DeclarationName N) { return N; }
2080	static QualType getPrintable(QualType T) { return T; }
2081	static SourceRange getPrintable(SourceRange R) { return R; }
2082	static SourceRange getPrintable(SourceLocation L) { return L; }
2083	static SourceRange getPrintable(const Expr *E) { return E->getSourceRange(); }
2084	static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange();}
2085
2086	template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
2087	protected:
2088	unsigned DiagID;
2089	std::tuple<const Ts &...> Args;
2090
2091	template <std::size_t... Is>
2092	void emit(const SemaDiagnosticBuilder &DB,
2093	std::index_sequence<Is...>) const {
2094	// Apply all tuple elements to the builder in order.
2095	bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
2096	(void)Dummy;
2097	}
2098
2099	public:
2100	BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
2101	: TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
2102	assert(DiagID != 0 && "no diagnostic for type diagnoser")((void)0);
2103	}
2104
2105	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
2106	const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
2107	emit(DB, std::index_sequence_for<Ts...>());
2108	DB << T;
2109	}
2110	};
2111
2112	/// Do a check to make sure \p Name looks like a legal argument for the
2113	/// swift_name attribute applied to decl \p D. Raise a diagnostic if the name
2114	/// is invalid for the given declaration.
2115	///
2116	/// \p AL is used to provide caret diagnostics in case of a malformed name.
2117	///
2118	/// \returns true if the name is a valid swift name for \p D, false otherwise.
2119	bool DiagnoseSwiftName(Decl *D, StringRef Name, SourceLocation Loc,
2120	const ParsedAttr &AL, bool IsAsync);
2121
2122	/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
2123	/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
2124	/// For example, a diagnostic with no other parameters would generally have
2125	/// the form "...%select{incomplete\|sizeless}0 type %1...".
2126	template <typename... Ts>
2127	class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
2128	public:
2129	SizelessTypeDiagnoser(unsigned DiagID, const Ts &... Args)
2130	: BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}
2131
2132	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
2133	const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
2134	this->emit(DB, std::index_sequence_for<Ts...>());
2135	DB << T->isSizelessType() << T;
2136	}
2137	};
2138
2139	enum class CompleteTypeKind {
2140	/// Apply the normal rules for complete types. In particular,
2141	/// treat all sizeless types as incomplete.
2142	Normal,
2143
2144	/// Relax the normal rules for complete types so that they include
2145	/// sizeless built-in types.
2146	AcceptSizeless,
2147
2148	// FIXME: Eventually we should flip the default to Normal and opt in
2149	// to AcceptSizeless rather than opt out of it.
2150	Default = AcceptSizeless
2151	};
2152
2153	private:
2154	/// Methods for marking which expressions involve dereferencing a pointer
2155	/// marked with the 'noderef' attribute. Expressions are checked bottom up as
2156	/// they are parsed, meaning that a noderef pointer may not be accessed. For
2157	/// example, in `&*p` where `p` is a noderef pointer, we will first parse the
2158	/// `*p`, but need to check that `address of` is called on it. This requires
2159	/// keeping a container of all pending expressions and checking if the address
2160	/// of them are eventually taken.
2161	void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
2162	void CheckAddressOfNoDeref(const Expr *E);
2163	void CheckMemberAccessOfNoDeref(const MemberExpr *E);
2164
2165	bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
2166	CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);
2167
2168	struct ModuleScope {
2169	SourceLocation BeginLoc;
2170	clang::Module *Module = nullptr;
2171	bool ModuleInterface = false;
2172	bool ImplicitGlobalModuleFragment = false;
2173	VisibleModuleSet OuterVisibleModules;
2174	};
2175	/// The modules we're currently parsing.
2176	llvm::SmallVector<ModuleScope, 16> ModuleScopes;
2177
2178	/// Namespace definitions that we will export when they finish.
2179	llvm::SmallPtrSet<const NamespaceDecl*, 8> DeferredExportedNamespaces;
2180
2181	/// Get the module whose scope we are currently within.
2182	Module *getCurrentModule() const {
2183	return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
2184	}
2185
2186	VisibleModuleSet VisibleModules;
2187
2188	public:
2189	/// Get the module owning an entity.
2190	Module getOwningModule(const Decl Entity) {
2191	return Entity->getOwningModule();
2192	}
2193
2194	/// Make a merged definition of an existing hidden definition \p ND
2195	/// visible at the specified location.
2196	void makeMergedDefinitionVisible(NamedDecl *ND);
2197
2198	bool isModuleVisible(const Module *M, bool ModulePrivate = false);
2199
2200	// When loading a non-modular PCH files, this is used to restore module
2201	// visibility.
2202	void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
2203	VisibleModules.setVisible(Mod, ImportLoc);
2204	}
2205
2206	/// Determine whether a declaration is visible to name lookup.
2207	bool isVisible(const NamedDecl *D) {
2208	return D->isUnconditionallyVisible() \|\| isVisibleSlow(D);
2209	}
2210
2211	/// Determine whether any declaration of an entity is visible.
2212	bool
2213	hasVisibleDeclaration(const NamedDecl *D,
2214	llvm::SmallVectorImpl<Module > Modules = nullptr) {
2215	return isVisible(D) \|\| hasVisibleDeclarationSlow(D, Modules);
2216	}
2217	bool hasVisibleDeclarationSlow(const NamedDecl *D,
2218	llvm::SmallVectorImpl<Module > Modules);
2219
2220	bool hasVisibleMergedDefinition(NamedDecl *Def);
2221	bool hasMergedDefinitionInCurrentModule(NamedDecl *Def);
2222
2223	/// Determine if \p D and \p Suggested have a structurally compatible
2224	/// layout as described in C11 6.2.7/1.
2225	bool hasStructuralCompatLayout(Decl D, Decl Suggested);
2226
2227	/// Determine if \p D has a visible definition. If not, suggest a declaration
2228	/// that should be made visible to expose the definition.
2229	bool hasVisibleDefinition(NamedDecl D, NamedDecl *Suggested,
2230	bool OnlyNeedComplete = false);
2231	bool hasVisibleDefinition(const NamedDecl *D) {
2232	NamedDecl *Hidden;
2233	return hasVisibleDefinition(const_cast<NamedDecl*>(D), &Hidden);
2234	}
2235
2236	/// Determine if the template parameter \p D has a visible default argument.
2237	bool
2238	hasVisibleDefaultArgument(const NamedDecl *D,
2239	llvm::SmallVectorImpl<Module > Modules = nullptr);
2240
2241	/// Determine if there is a visible declaration of \p D that is an explicit
2242	/// specialization declaration for a specialization of a template. (For a
2243	/// member specialization, use hasVisibleMemberSpecialization.)
2244	bool hasVisibleExplicitSpecialization(
2245	const NamedDecl D, llvm::SmallVectorImpl<Module > *Modules = nullptr);
2246
2247	/// Determine if there is a visible declaration of \p D that is a member
2248	/// specialization declaration (as opposed to an instantiated declaration).
2249	bool hasVisibleMemberSpecialization(
2250	const NamedDecl D, llvm::SmallVectorImpl<Module > *Modules = nullptr);
2251
2252	/// Determine if \p A and \p B are equivalent internal linkage declarations
2253	/// from different modules, and thus an ambiguity error can be downgraded to
2254	/// an extension warning.
2255	bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
2256	const NamedDecl *B);
2257	void diagnoseEquivalentInternalLinkageDeclarations(
2258	SourceLocation Loc, const NamedDecl *D,
2259	ArrayRef<const NamedDecl *> Equiv);
2260
2261	bool isUsualDeallocationFunction(const CXXMethodDecl *FD);
2262
2263	bool isCompleteType(SourceLocation Loc, QualType T,
2264	CompleteTypeKind Kind = CompleteTypeKind::Default) {
2265	return !RequireCompleteTypeImpl(Loc, T, Kind, nullptr);
2266	}
2267	bool RequireCompleteType(SourceLocation Loc, QualType T,
2268	CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
2269	bool RequireCompleteType(SourceLocation Loc, QualType T,
2270	CompleteTypeKind Kind, unsigned DiagID);
2271
2272	bool RequireCompleteType(SourceLocation Loc, QualType T,
2273	TypeDiagnoser &Diagnoser) {
2274	return RequireCompleteType(Loc, T, CompleteTypeKind::Default, Diagnoser);
2275	}
2276	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
2277	return RequireCompleteType(Loc, T, CompleteTypeKind::Default, DiagID);
2278	}
2279
2280	template <typename... Ts>
2281	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
2282	const Ts &...Args) {
2283	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
2284	return RequireCompleteType(Loc, T, Diagnoser);
2285	}
2286
2287	template <typename... Ts>
2288	bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
2289	const Ts &... Args) {
2290	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
2291	return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
2292	}
2293
2294	/// Get the type of expression E, triggering instantiation to complete the
2295	/// type if necessary -- that is, if the expression refers to a templated
2296	/// static data member of incomplete array type.
2297	///
2298	/// May still return an incomplete type if instantiation was not possible or
2299	/// if the type is incomplete for a different reason. Use
2300	/// RequireCompleteExprType instead if a diagnostic is expected for an
2301	/// incomplete expression type.
2302	QualType getCompletedType(Expr *E);
2303
2304	void completeExprArrayBound(Expr *E);
2305	bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
2306	TypeDiagnoser &Diagnoser);
2307	bool RequireCompleteExprType(Expr *E, unsigned DiagID);
2308
2309	template <typename... Ts>
2310	bool RequireCompleteExprType(Expr *E, unsigned DiagID, const Ts &...Args) {
2311	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
2312	return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
2313	}
2314
2315	template <typename... Ts>
2316	bool RequireCompleteSizedExprType(Expr *E, unsigned DiagID,
2317	const Ts &... Args) {
2318	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
2319	return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
2320	}
2321
2322	bool RequireLiteralType(SourceLocation Loc, QualType T,
2323	TypeDiagnoser &Diagnoser);
2324	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);
2325
2326	template <typename... Ts>
2327	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
2328	const Ts &...Args) {
2329	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
2330	return RequireLiteralType(Loc, T, Diagnoser);
2331	}
2332
2333	QualType getElaboratedType(ElaboratedTypeKeyword Keyword,
2334	const CXXScopeSpec &SS, QualType T,
2335	TagDecl *OwnedTagDecl = nullptr);
2336
2337	QualType getDecltypeForParenthesizedExpr(Expr *E);
2338	QualType BuildTypeofExprType(Expr *E, SourceLocation Loc);
2339	/// If AsUnevaluated is false, E is treated as though it were an evaluated
2340	/// context, such as when building a type for decltype(auto).
2341	QualType BuildDecltypeType(Expr *E, SourceLocation Loc,
2342	bool AsUnevaluated = true);
2343	QualType BuildUnaryTransformType(QualType BaseType,
2344	UnaryTransformType::UTTKind UKind,
2345	SourceLocation Loc);
2346
2347	//===--------------------------------------------------------------------===//
2348	// Symbol table / Decl tracking callbacks: SemaDecl.cpp.
2349	//
2350
2351	struct SkipBodyInfo {
2352	SkipBodyInfo()
2353	: ShouldSkip(false), CheckSameAsPrevious(false), Previous(nullptr),
2354	New(nullptr) {}
2355	bool ShouldSkip;
2356	bool CheckSameAsPrevious;
2357	NamedDecl *Previous;
2358	NamedDecl *New;
2359	};