ExprCXX.cpp

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//===- ExprCXX.cpp - (C++) Expression AST Node Implementation -------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the subclesses of Expr class declared in ExprCXX.h
//
//===----------------------------------------------------------------------===//

#include "clang/AST/ExprCXX.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclAccessPair.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Expr.h"
#include "clang/AST/LambdaCapture.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include <cassert>
#include <cstddef>
#include <cstring>
#include <memory>

using namespace clang;

//===----------------------------------------------------------------------===//
//  Child Iterators for iterating over subexpressions/substatements
//===----------------------------------------------------------------------===//

bool CXXOperatorCallExpr::isInfixBinaryOp() const {
  // An infix binary operator is any operator with two arguments other than
  // operator() and operator[]. Note that none of these operators can have
  // default arguments, so it suffices to check the number of argument
  // expressions.
  if (getNumArgs() != 2)
    return false;

  switch (getOperator()) {
  case OO_Call: case OO_Subscript:
    return false;
  default:
    return true;
  }
}

bool CXXTypeidExpr::isPotentiallyEvaluated() const {
  if (isTypeOperand())
    return false;

  // C++11 [expr.typeid]p3:
  //   When typeid is applied to an expression other than a glvalue of
  //   polymorphic class type, [...] the expression is an unevaluated operand.
  const Expr *E = getExprOperand();
  if (const CXXRecordDecl *RD = E->getType()->getAsCXXRecordDecl())
    if (RD->isPolymorphic() && E->isGLValue())
      return true;

  return false;
}

QualType CXXTypeidExpr::getTypeOperand(ASTContext &Context) const {
  assert(isTypeOperand() && "Cannot call getTypeOperand for typeid(expr)");
  Qualifiers Quals;
  return Context.getUnqualifiedArrayType(
      Operand.get<TypeSourceInfo *>()->getType().getNonReferenceType(), Quals);
}

QualType CXXUuidofExpr::getTypeOperand(ASTContext &Context) const {
  assert(isTypeOperand() && "Cannot call getTypeOperand for __uuidof(expr)");
  Qualifiers Quals;
  return Context.getUnqualifiedArrayType(
      Operand.get<TypeSourceInfo *>()->getType().getNonReferenceType(), Quals);
}

// CXXScalarValueInitExpr
SourceLocation CXXScalarValueInitExpr::getBeginLoc() const {
  return TypeInfo ? TypeInfo->getTypeLoc().getBeginLoc() : RParenLoc;
}

// CXXNewExpr
CXXNewExpr::CXXNewExpr(const ASTContext &C, bool globalNew,
                       FunctionDecl *operatorNew, FunctionDecl *operatorDelete,
                       bool PassAlignment, bool usualArrayDeleteWantsSize,
                       ArrayRef<Expr*> placementArgs,
                       SourceRange typeIdParens, Expr *arraySize,
                       InitializationStyle initializationStyle,
                       Expr *initializer, QualType ty,
                       TypeSourceInfo *allocatedTypeInfo,
                       SourceRange Range, SourceRange directInitRange)
    : Expr(CXXNewExprClass, ty, VK_RValue, OK_Ordinary, ty->isDependentType(),
           ty->isDependentType(), ty->isInstantiationDependentType(),
           ty->containsUnexpandedParameterPack()),
      OperatorNew(operatorNew), OperatorDelete(operatorDelete),
      AllocatedTypeInfo(allocatedTypeInfo), TypeIdParens(typeIdParens),
      Range(Range), DirectInitRange(directInitRange), GlobalNew(globalNew),
      PassAlignment(PassAlignment),
      UsualArrayDeleteWantsSize(usualArrayDeleteWantsSize) {
  assert((initializer != nullptr || initializationStyle == NoInit) &&
         "Only NoInit can have no initializer.");
  StoredInitializationStyle = initializer ? initializationStyle + 1 : 0;
  AllocateArgsArray(C, arraySize != nullptr, placementArgs.size(),
                    initializer != nullptr);
  unsigned i = 0;
  if (Array) {
    if (arraySize->isInstantiationDependent())
      ExprBits.InstantiationDependent = true;

    if (arraySize->containsUnexpandedParameterPack())
      ExprBits.ContainsUnexpandedParameterPack = true;

    SubExprs[i++] = arraySize;
  }

  if (initializer) {
    if (initializer->isInstantiationDependent())
      ExprBits.InstantiationDependent = true;

    if (initializer->containsUnexpandedParameterPack())
      ExprBits.ContainsUnexpandedParameterPack = true;

    SubExprs[i++] = initializer;
  }

  for (unsigned j = 0; j != placementArgs.size(); ++j) {
    if (placementArgs[j]->isInstantiationDependent())
      ExprBits.InstantiationDependent = true;
    if (placementArgs[j]->containsUnexpandedParameterPack())
      ExprBits.ContainsUnexpandedParameterPack = true;

    SubExprs[i++] = placementArgs[j];
  }

  switch (getInitializationStyle()) {
  case CallInit:
    this->Range.setEnd(DirectInitRange.getEnd()); break;
  case ListInit:
    this->Range.setEnd(getInitializer()->getSourceRange().getEnd()); break;
  default:
    if (TypeIdParens.isValid())
      this->Range.setEnd(TypeIdParens.getEnd());
    break;
  }
}

void CXXNewExpr::AllocateArgsArray(const ASTContext &C, bool isArray,
                                   unsigned numPlaceArgs, bool hasInitializer){
  assert(SubExprs == nullptr && "SubExprs already allocated");
  Array = isArray;
  NumPlacementArgs = numPlaceArgs;

  unsigned TotalSize = Array + hasInitializer + NumPlacementArgs;
  SubExprs = new (C) Stmt*[TotalSize];
}

bool CXXNewExpr::shouldNullCheckAllocation(const ASTContext &Ctx) const {
  return getOperatorNew()->getType()->castAs<FunctionProtoType>()
                                          ->isNothrow() &&
         !getOperatorNew()->isReservedGlobalPlacementOperator();
}

// CXXDeleteExpr
QualType CXXDeleteExpr::getDestroyedType() const {
  const Expr *Arg = getArgument();

  // For a destroying operator delete, we may have implicitly converted the
  // pointer type to the type of the parameter of the 'operator delete'
  // function.
  while (const auto *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
    if (ICE->getCastKind() == CK_DerivedToBase ||
        ICE->getCastKind() == CK_UncheckedDerivedToBase ||
        ICE->getCastKind() == CK_NoOp) {
      assert((ICE->getCastKind() == CK_NoOp ||
              getOperatorDelete()->isDestroyingOperatorDelete()) &&
             "only a destroying operator delete can have a converted arg");
      Arg = ICE->getSubExpr();
    } else
      break;
  }

  // The type-to-delete may not be a pointer if it's a dependent type.
  const QualType ArgType = Arg->getType();

  if (ArgType->isDependentType() && !ArgType->isPointerType())
    return QualType();

  return ArgType->getAs<PointerType>()->getPointeeType();
}

// CXXPseudoDestructorExpr
PseudoDestructorTypeStorage::PseudoDestructorTypeStorage(TypeSourceInfo *Info)
    : Type(Info) {
  Location = Info->getTypeLoc().getLocalSourceRange().getBegin();
}

CXXPseudoDestructorExpr::CXXPseudoDestructorExpr(const ASTContext &Context,
                Expr *Base, bool isArrow, SourceLocation OperatorLoc,
                NestedNameSpecifierLoc QualifierLoc, TypeSourceInfo *ScopeType,
                SourceLocation ColonColonLoc, SourceLocation TildeLoc,
                PseudoDestructorTypeStorage DestroyedType)
  : Expr(CXXPseudoDestructorExprClass,
         Context.BoundMemberTy,
         VK_RValue, OK_Ordinary,
         /*isTypeDependent=*/(Base->isTypeDependent() ||
           (DestroyedType.getTypeSourceInfo() &&
            DestroyedType.getTypeSourceInfo()->getType()->isDependentType())),
         /*isValueDependent=*/Base->isValueDependent(),
         (Base->isInstantiationDependent() ||
          (QualifierLoc &&
           QualifierLoc.getNestedNameSpecifier()->isInstantiationDependent()) ||
          (ScopeType &&
           ScopeType->getType()->isInstantiationDependentType()) ||
          (DestroyedType.getTypeSourceInfo() &&
           DestroyedType.getTypeSourceInfo()->getType()
                                             ->isInstantiationDependentType())),
         // ContainsUnexpandedParameterPack
         (Base->containsUnexpandedParameterPack() ||
          (QualifierLoc &&
           QualifierLoc.getNestedNameSpecifier()
                                        ->containsUnexpandedParameterPack()) ||
          (ScopeType &&
           ScopeType->getType()->containsUnexpandedParameterPack()) ||
          (DestroyedType.getTypeSourceInfo() &&
           DestroyedType.getTypeSourceInfo()->getType()
                                   ->containsUnexpandedParameterPack()))),
    Base(static_cast<Stmt *>(Base)), IsArrow(isArrow),
    OperatorLoc(OperatorLoc), QualifierLoc(QualifierLoc),
    ScopeType(ScopeType), ColonColonLoc(ColonColonLoc), TildeLoc(TildeLoc),
    DestroyedType(DestroyedType) {}

QualType CXXPseudoDestructorExpr::getDestroyedType() const {
  if (TypeSourceInfo *TInfo = DestroyedType.getTypeSourceInfo())
    return TInfo->getType();

  return QualType();
}

SourceLocation CXXPseudoDestructorExpr::getEndLoc() const {
  SourceLocation End = DestroyedType.getLocation();
  if (TypeSourceInfo *TInfo = DestroyedType.getTypeSourceInfo())
    End = TInfo->getTypeLoc().getLocalSourceRange().getEnd();
  return End;
}

// UnresolvedLookupExpr
UnresolvedLookupExpr *
UnresolvedLookupExpr::Create(const ASTContext &C,
                             CXXRecordDecl *NamingClass,
                             NestedNameSpecifierLoc QualifierLoc,
                             SourceLocation TemplateKWLoc,
                             const DeclarationNameInfo &NameInfo,
                             bool ADL,
                             const TemplateArgumentListInfo *Args,
                             UnresolvedSetIterator Begin,
                             UnresolvedSetIterator End) {
  assert(Args || TemplateKWLoc.isValid());
  unsigned num_args = Args ? Args->size() : 0;

  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(1,
                                                                      num_args);
  void *Mem = C.Allocate(Size, alignof(UnresolvedLookupExpr));
  return new (Mem) UnresolvedLookupExpr(C, NamingClass, QualifierLoc,
                                        TemplateKWLoc, NameInfo,
                                        ADL, /*Overload*/ true, Args,
                                        Begin, End);
}

UnresolvedLookupExpr *
UnresolvedLookupExpr::CreateEmpty(const ASTContext &C,
                                  bool HasTemplateKWAndArgsInfo,
                                  unsigned NumTemplateArgs) {
  assert(NumTemplateArgs == 0 || HasTemplateKWAndArgsInfo);
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, NumTemplateArgs);
  void *Mem = C.Allocate(Size, alignof(UnresolvedLookupExpr));
  auto *E = new (Mem) UnresolvedLookupExpr(EmptyShell());
  E->HasTemplateKWAndArgsInfo = HasTemplateKWAndArgsInfo;
  return E;
}

OverloadExpr::OverloadExpr(StmtClass K, const ASTContext &C,
                           NestedNameSpecifierLoc QualifierLoc,
                           SourceLocation TemplateKWLoc,
                           const DeclarationNameInfo &NameInfo,
                           const TemplateArgumentListInfo *TemplateArgs,
                           UnresolvedSetIterator Begin,
                           UnresolvedSetIterator End,
                           bool KnownDependent,
                           bool KnownInstantiationDependent,
                           bool KnownContainsUnexpandedParameterPack)
    : Expr(K, C.OverloadTy, VK_LValue, OK_Ordinary, KnownDependent,
           KnownDependent,
           (KnownInstantiationDependent ||
            NameInfo.isInstantiationDependent() ||
            (QualifierLoc &&
            QualifierLoc.getNestedNameSpecifier()->isInstantiationDependent())),
           (KnownContainsUnexpandedParameterPack ||
            NameInfo.containsUnexpandedParameterPack() ||
            (QualifierLoc &&
             QualifierLoc.getNestedNameSpecifier()
                                        ->containsUnexpandedParameterPack()))),
      NameInfo(NameInfo), QualifierLoc(QualifierLoc), NumResults(End - Begin),
      HasTemplateKWAndArgsInfo(TemplateArgs != nullptr ||
                               TemplateKWLoc.isValid()) {
  NumResults = End - Begin;
  if (NumResults) {
    // Determine whether this expression is type-dependent.
    for (UnresolvedSetImpl::const_iterator I = Begin; I != End; ++I) {
      if ((*I)->getDeclContext()->isDependentContext() ||
          isa<UnresolvedUsingValueDecl>(*I)) {
        ExprBits.TypeDependent = true;
        ExprBits.ValueDependent = true;
        ExprBits.InstantiationDependent = true;
      }
    }

    Results = static_cast<DeclAccessPair *>(C.Allocate(
        sizeof(DeclAccessPair) * NumResults, alignof(DeclAccessPair)));
    memcpy(Results, Begin.I, NumResults * sizeof(DeclAccessPair));
  }

  // If we have explicit template arguments, check for dependent
  // template arguments and whether they contain any unexpanded pack
  // expansions.
  if (TemplateArgs) {
    bool Dependent = false;
    bool InstantiationDependent = false;
    bool ContainsUnexpandedParameterPack = false;
    getTrailingASTTemplateKWAndArgsInfo()->initializeFrom(
        TemplateKWLoc, *TemplateArgs, getTrailingTemplateArgumentLoc(),
        Dependent, InstantiationDependent, ContainsUnexpandedParameterPack);

    if (Dependent) {
      ExprBits.TypeDependent = true;
      ExprBits.ValueDependent = true;
    }
    if (InstantiationDependent)
      ExprBits.InstantiationDependent = true;
    if (ContainsUnexpandedParameterPack)
      ExprBits.ContainsUnexpandedParameterPack = true;
  } else if (TemplateKWLoc.isValid()) {
    getTrailingASTTemplateKWAndArgsInfo()->initializeFrom(TemplateKWLoc);
  }

  if (isTypeDependent())
    setType(C.DependentTy);
}

void OverloadExpr::initializeResults(const ASTContext &C,
                                     UnresolvedSetIterator Begin,
                                     UnresolvedSetIterator End) {
  assert(!Results && "Results already initialized!");
  NumResults = End - Begin;
  if (NumResults) {
    Results = static_cast<DeclAccessPair *>(
        C.Allocate(sizeof(DeclAccessPair) * NumResults,

                   alignof(DeclAccessPair)));
    memcpy(Results, Begin.I, NumResults * sizeof(DeclAccessPair));
  }
}

CXXRecordDecl *OverloadExpr::getNamingClass() const {
  if (isa<UnresolvedLookupExpr>(this))
    return cast<UnresolvedLookupExpr>(this)->getNamingClass();
  else
    return cast<UnresolvedMemberExpr>(this)->getNamingClass();
}

// DependentScopeDeclRefExpr
DependentScopeDeclRefExpr::DependentScopeDeclRefExpr(QualType T,
                            NestedNameSpecifierLoc QualifierLoc,
                            SourceLocation TemplateKWLoc,
                            const DeclarationNameInfo &NameInfo,
                            const TemplateArgumentListInfo *Args)
  : Expr(DependentScopeDeclRefExprClass, T, VK_LValue, OK_Ordinary,
         true, true,
         (NameInfo.isInstantiationDependent() ||
          (QualifierLoc &&
           QualifierLoc.getNestedNameSpecifier()->isInstantiationDependent())),
         (NameInfo.containsUnexpandedParameterPack() ||
          (QualifierLoc &&
           QualifierLoc.getNestedNameSpecifier()
                            ->containsUnexpandedParameterPack()))),
    QualifierLoc(QualifierLoc), NameInfo(NameInfo),
    HasTemplateKWAndArgsInfo(Args != nullptr || TemplateKWLoc.isValid())
{
  if (Args) {
    bool Dependent = true;
    bool InstantiationDependent = true;
    bool ContainsUnexpandedParameterPack
      = ExprBits.ContainsUnexpandedParameterPack;
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc, *Args, getTrailingObjects<TemplateArgumentLoc>(),
        Dependent, InstantiationDependent, ContainsUnexpandedParameterPack);
    ExprBits.ContainsUnexpandedParameterPack = ContainsUnexpandedParameterPack;
  } else if (TemplateKWLoc.isValid()) {
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc);
  }
}

DependentScopeDeclRefExpr *
DependentScopeDeclRefExpr::Create(const ASTContext &C,
                                  NestedNameSpecifierLoc QualifierLoc,
                                  SourceLocation TemplateKWLoc,
                                  const DeclarationNameInfo &NameInfo,
                                  const TemplateArgumentListInfo *Args) {
  assert(QualifierLoc && "should be created for dependent qualifiers");
  bool HasTemplateKWAndArgsInfo = Args || TemplateKWLoc.isValid();
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, Args ? Args->size() : 0);
  void *Mem = C.Allocate(Size);
  return new (Mem) DependentScopeDeclRefExpr(C.DependentTy, QualifierLoc,
                                             TemplateKWLoc, NameInfo, Args);
}

DependentScopeDeclRefExpr *
DependentScopeDeclRefExpr::CreateEmpty(const ASTContext &C,
                                       bool HasTemplateKWAndArgsInfo,
                                       unsigned NumTemplateArgs) {
  assert(NumTemplateArgs == 0 || HasTemplateKWAndArgsInfo);
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, NumTemplateArgs);
  void *Mem = C.Allocate(Size);
  auto *E =
      new (Mem) DependentScopeDeclRefExpr(QualType(), NestedNameSpecifierLoc(),
                                          SourceLocation(),
                                          DeclarationNameInfo(), nullptr);
  E->HasTemplateKWAndArgsInfo = HasTemplateKWAndArgsInfo;
  return E;
}

SourceLocation CXXConstructExpr::getBeginLoc() const {
  if (isa<CXXTemporaryObjectExpr>(this))
    return cast<CXXTemporaryObjectExpr>(this)->getBeginLoc();
  return Loc;
}

SourceLocation CXXConstructExpr::getEndLoc() const {
  if (isa<CXXTemporaryObjectExpr>(this))
    return cast<CXXTemporaryObjectExpr>(this)->getEndLoc();

  if (ParenOrBraceRange.isValid())
    return ParenOrBraceRange.getEnd();

  SourceLocation End = Loc;
  for (unsigned I = getNumArgs(); I > 0; --I) {
    const Expr *Arg = getArg(I-1);
    if (!Arg->isDefaultArgument()) {
      SourceLocation NewEnd = Arg->getEndLoc();
      if (NewEnd.isValid()) {
        End = NewEnd;
        break;
      }
    }
  }

  return End;
}

SourceRange CXXOperatorCallExpr::getSourceRangeImpl() const {
  OverloadedOperatorKind Kind = getOperator();
  if (Kind == OO_PlusPlus || Kind == OO_MinusMinus) {
    if (getNumArgs() == 1)
      // Prefix operator
      return SourceRange(getOperatorLoc(), getArg(0)->getEndLoc());
    else
      // Postfix operator
      return SourceRange(getArg(0)->getBeginLoc(), getOperatorLoc());
  } else if (Kind == OO_Arrow) {
    return getArg(0)->getSourceRange();
  } else if (Kind == OO_Call) {
    return SourceRange(getArg(0)->getBeginLoc(), getRParenLoc());
  } else if (Kind == OO_Subscript) {
    return SourceRange(getArg(0)->getBeginLoc(), getRParenLoc());
  } else if (getNumArgs() == 1) {
    return SourceRange(getOperatorLoc(), getArg(0)->getEndLoc());
  } else if (getNumArgs() == 2) {
    return SourceRange(getArg(0)->getBeginLoc(), getArg(1)->getEndLoc());
  } else {
    return getOperatorLoc();
  }
}

Expr *CXXMemberCallExpr::getImplicitObjectArgument() const {
  const Expr *Callee = getCallee()->IgnoreParens();
  if (const auto *MemExpr = dyn_cast<MemberExpr>(Callee))
    return MemExpr->getBase();
  if (const auto *BO = dyn_cast<BinaryOperator>(Callee))
    if (BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI)
      return BO->getLHS();

  // FIXME: Will eventually need to cope with member pointers.
  return nullptr;
}

CXXMethodDecl *CXXMemberCallExpr::getMethodDecl() const {
  if (const auto *MemExpr = dyn_cast<MemberExpr>(getCallee()->IgnoreParens()))
    return cast<CXXMethodDecl>(MemExpr->getMemberDecl());

  // FIXME: Will eventually need to cope with member pointers.
  return nullptr;
}

CXXRecordDecl *CXXMemberCallExpr::getRecordDecl() const {
  Expr* ThisArg = getImplicitObjectArgument();
  if (!ThisArg)
    return nullptr;

  if (ThisArg->getType()->isAnyPointerType())
    return ThisArg->getType()->getPointeeType()->getAsCXXRecordDecl();

  return ThisArg->getType()->getAsCXXRecordDecl();
}

//===----------------------------------------------------------------------===//
//  Named casts
//===----------------------------------------------------------------------===//

/// getCastName - Get the name of the C++ cast being used, e.g.,
/// "static_cast", "dynamic_cast", "reinterpret_cast", or
/// "const_cast". The returned pointer must not be freed.
const char *CXXNamedCastExpr::getCastName() const {
  switch (getStmtClass()) {
  case CXXStaticCastExprClass:      return "static_cast";
  case CXXDynamicCastExprClass:     return "dynamic_cast";
  case CXXReinterpretCastExprClass: return "reinterpret_cast";
  case CXXConstCastExprClass:       return "const_cast";
  default:                          return "<invalid cast>";
  }
}

CXXStaticCastExpr *CXXStaticCastExpr::Create(const ASTContext &C, QualType T,
                                             ExprValueKind VK,
                                             CastKind K, Expr *Op,
                                             const CXXCastPath *BasePath,
                                             TypeSourceInfo *WrittenTy,
                                             SourceLocation L,
                                             SourceLocation RParenLoc,
                                             SourceRange AngleBrackets) {
  unsigned PathSize = (BasePath ? BasePath->size() : 0);
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  auto *E =
      new (Buffer) CXXStaticCastExpr(T, VK, K, Op, PathSize, WrittenTy, L,
                                     RParenLoc, AngleBrackets);
  if (PathSize)
    std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                              E->getTrailingObjects<CXXBaseSpecifier *>());
  return E;
}

CXXStaticCastExpr *CXXStaticCastExpr::CreateEmpty(const ASTContext &C,
                                                  unsigned PathSize) {
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  return new (Buffer) CXXStaticCastExpr(EmptyShell(), PathSize);
}

CXXDynamicCastExpr *CXXDynamicCastExpr::Create(const ASTContext &C, QualType T,
                                               ExprValueKind VK,
                                               CastKind K, Expr *Op,
                                               const CXXCastPath *BasePath,
                                               TypeSourceInfo *WrittenTy,
                                               SourceLocation L,
                                               SourceLocation RParenLoc,
                                               SourceRange AngleBrackets) {
  unsigned PathSize = (BasePath ? BasePath->size() : 0);
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  auto *E =
      new (Buffer) CXXDynamicCastExpr(T, VK, K, Op, PathSize, WrittenTy, L,
                                      RParenLoc, AngleBrackets);
  if (PathSize)
    std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                              E->getTrailingObjects<CXXBaseSpecifier *>());
  return E;
}

CXXDynamicCastExpr *CXXDynamicCastExpr::CreateEmpty(const ASTContext &C,
                                                    unsigned PathSize) {
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  return new (Buffer) CXXDynamicCastExpr(EmptyShell(), PathSize);
}

/// isAlwaysNull - Return whether the result of the dynamic_cast is proven
/// to always be null. For example:
///
/// struct A { };
/// struct B final : A { };
/// struct C { };
///
/// C *f(B* b) { return dynamic_cast<C*>(b); }
bool CXXDynamicCastExpr::isAlwaysNull() const
{
  QualType SrcType = getSubExpr()->getType();
  QualType DestType = getType();

  if (const auto *SrcPTy = SrcType->getAs<PointerType>()) {
    SrcType = SrcPTy->getPointeeType();
    DestType = DestType->castAs<PointerType>()->getPointeeType();
  }

  if (DestType->isVoidType())
    return false;

  const auto *SrcRD =
      cast<CXXRecordDecl>(SrcType->castAs<RecordType>()->getDecl());

  if (!SrcRD->hasAttr<FinalAttr>())
    return false;

  const auto *DestRD =
      cast<CXXRecordDecl>(DestType->castAs<RecordType>()->getDecl());

  return !DestRD->isDerivedFrom(SrcRD);
}

CXXReinterpretCastExpr *
CXXReinterpretCastExpr::Create(const ASTContext &C, QualType T,
                               ExprValueKind VK, CastKind K, Expr *Op,
                               const CXXCastPath *BasePath,
                               TypeSourceInfo *WrittenTy, SourceLocation L,
                               SourceLocation RParenLoc,
                               SourceRange AngleBrackets) {
  unsigned PathSize = (BasePath ? BasePath->size() : 0);
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  auto *E =
      new (Buffer) CXXReinterpretCastExpr(T, VK, K, Op, PathSize, WrittenTy, L,
                                          RParenLoc, AngleBrackets);
  if (PathSize)
    std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                              E->getTrailingObjects<CXXBaseSpecifier *>());
  return E;
}

CXXReinterpretCastExpr *
CXXReinterpretCastExpr::CreateEmpty(const ASTContext &C, unsigned PathSize) {
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  return new (Buffer) CXXReinterpretCastExpr(EmptyShell(), PathSize);
}

CXXConstCastExpr *CXXConstCastExpr::Create(const ASTContext &C, QualType T,
                                           ExprValueKind VK, Expr *Op,
                                           TypeSourceInfo *WrittenTy,
                                           SourceLocation L,
                                           SourceLocation RParenLoc,
                                           SourceRange AngleBrackets) {
  return new (C) CXXConstCastExpr(T, VK, Op, WrittenTy, L, RParenLoc, AngleBrackets);
}

CXXConstCastExpr *CXXConstCastExpr::CreateEmpty(const ASTContext &C) {
  return new (C) CXXConstCastExpr(EmptyShell());
}

CXXFunctionalCastExpr *
CXXFunctionalCastExpr::Create(const ASTContext &C, QualType T, ExprValueKind VK,
                              TypeSourceInfo *Written, CastKind K, Expr *Op,
                              const CXXCastPath *BasePath,
                              SourceLocation L, SourceLocation R) {
  unsigned PathSize = (BasePath ? BasePath->size() : 0);
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  auto *E =
      new (Buffer) CXXFunctionalCastExpr(T, VK, Written, K, Op, PathSize, L, R);
  if (PathSize)
    std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                              E->getTrailingObjects<CXXBaseSpecifier *>());
  return E;
}

CXXFunctionalCastExpr *
CXXFunctionalCastExpr::CreateEmpty(const ASTContext &C, unsigned PathSize) {
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CastExpr::BasePathSizeTy, CXXBaseSpecifier *>(
          PathSize ? 1 : 0, PathSize));
  return new (Buffer) CXXFunctionalCastExpr(EmptyShell(), PathSize);
}

SourceLocation CXXFunctionalCastExpr::getBeginLoc() const {
  return getTypeInfoAsWritten()->getTypeLoc().getBeginLoc();
}

SourceLocation CXXFunctionalCastExpr::getEndLoc() const {
  return RParenLoc.isValid() ? RParenLoc : getSubExpr()->getEndLoc();
}

UserDefinedLiteral::LiteralOperatorKind
UserDefinedLiteral::getLiteralOperatorKind() const {
  if (getNumArgs() == 0)
    return LOK_Template;
  if (getNumArgs() == 2)
    return LOK_String;

  assert(getNumArgs() == 1 && "unexpected #args in literal operator call");
  QualType ParamTy =
    cast<FunctionDecl>(getCalleeDecl())->getParamDecl(0)->getType();
  if (ParamTy->isPointerType())
    return LOK_Raw;
  if (ParamTy->isAnyCharacterType())
    return LOK_Character;
  if (ParamTy->isIntegerType())
    return LOK_Integer;
  if (ParamTy->isFloatingType())
    return LOK_Floating;

  llvm_unreachable("unknown kind of literal operator");
}

Expr *UserDefinedLiteral::getCookedLiteral() {
#ifndef NDEBUG
  LiteralOperatorKind LOK = getLiteralOperatorKind();
  assert(LOK != LOK_Template && LOK != LOK_Raw && "not a cooked literal");
#endif
  return getArg(0);
}

const IdentifierInfo *UserDefinedLiteral::getUDSuffix() const {
  return cast<FunctionDecl>(getCalleeDecl())->getLiteralIdentifier();
}

CXXDefaultInitExpr::CXXDefaultInitExpr(const ASTContext &C, SourceLocation Loc,
                                       FieldDecl *Field, QualType T)
    : Expr(CXXDefaultInitExprClass, T.getNonLValueExprType(C),
           T->isLValueReferenceType() ? VK_LValue : T->isRValueReferenceType()
                                                        ? VK_XValue
                                                        : VK_RValue,
           /*FIXME*/ OK_Ordinary, false, false, false, false),
      Field(Field), Loc(Loc) {
  assert(Field->hasInClassInitializer());
}

CXXTemporary *CXXTemporary::Create(const ASTContext &C,
                                   const CXXDestructorDecl *Destructor) {
  return new (C) CXXTemporary(Destructor);
}

CXXBindTemporaryExpr *CXXBindTemporaryExpr::Create(const ASTContext &C,
                                                   CXXTemporary *Temp,
                                                   Expr* SubExpr) {
  assert((SubExpr->getType()->isRecordType() ||
          SubExpr->getType()->isArrayType()) &&
         "Expression bound to a temporary must have record or array type!");

  return new (C) CXXBindTemporaryExpr(Temp, SubExpr);
}

CXXTemporaryObjectExpr::CXXTemporaryObjectExpr(const ASTContext &C,
                                               CXXConstructorDecl *Cons,
                                               QualType Type,
                                               TypeSourceInfo *TSI,
                                               ArrayRef<Expr*> Args,
                                               SourceRange ParenOrBraceRange,
                                               bool HadMultipleCandidates,
                                               bool ListInitialization,
                                               bool StdInitListInitialization,
                                               bool ZeroInitialization)
    : CXXConstructExpr(C, CXXTemporaryObjectExprClass, Type,
                       TSI->getTypeLoc().getBeginLoc(), Cons, false, Args,
                       HadMultipleCandidates, ListInitialization,
                       StdInitListInitialization,  ZeroInitialization,
                       CXXConstructExpr::CK_Complete, ParenOrBraceRange),
      Type(TSI) {}

SourceLocation CXXTemporaryObjectExpr::getBeginLoc() const {
  return Type->getTypeLoc().getBeginLoc();
}

SourceLocation CXXTemporaryObjectExpr::getEndLoc() const {
  SourceLocation Loc = getParenOrBraceRange().getEnd();
  if (Loc.isInvalid() && getNumArgs())
    Loc = getArg(getNumArgs() - 1)->getEndLoc();
  return Loc;
}

CXXConstructExpr *CXXConstructExpr::Create(const ASTContext &C, QualType T,
                                           SourceLocation Loc,
                                           CXXConstructorDecl *Ctor,
                                           bool Elidable,
                                           ArrayRef<Expr*> Args,
                                           bool HadMultipleCandidates,
                                           bool ListInitialization,
                                           bool StdInitListInitialization,
                                           bool ZeroInitialization,
                                           ConstructionKind ConstructKind,
                                           SourceRange ParenOrBraceRange) {
  return new (C) CXXConstructExpr(C, CXXConstructExprClass, T, Loc,
                                  Ctor, Elidable, Args,
                                  HadMultipleCandidates, ListInitialization,
                                  StdInitListInitialization,
                                  ZeroInitialization, ConstructKind,
                                  ParenOrBraceRange);
}

CXXConstructExpr::CXXConstructExpr(const ASTContext &C, StmtClass SC,
                                   QualType T, SourceLocation Loc,
                                   CXXConstructorDecl *Ctor,
                                   bool Elidable,
                                   ArrayRef<Expr*> Args,
                                   bool HadMultipleCandidates,
                                   bool ListInitialization,
                                   bool StdInitListInitialization,
                                   bool ZeroInitialization,
                                   ConstructionKind ConstructKind,
                                   SourceRange ParenOrBraceRange)
    : Expr(SC, T, VK_RValue, OK_Ordinary,
           T->isDependentType(), T->isDependentType(),
           T->isInstantiationDependentType(),
           T->containsUnexpandedParameterPack()),
      Constructor(Ctor), Loc(Loc), ParenOrBraceRange(ParenOrBraceRange),
      NumArgs(Args.size()), Elidable(Elidable),
      HadMultipleCandidates(HadMultipleCandidates),
      ListInitialization(ListInitialization),
      StdInitListInitialization(StdInitListInitialization),
      ZeroInitialization(ZeroInitialization), ConstructKind(ConstructKind) {
  if (NumArgs) {
    this->Args = new (C) Stmt*[Args.size()];

    for (unsigned i = 0; i != Args.size(); ++i) {
      assert(Args[i] && "NULL argument in CXXConstructExpr");

      if (Args[i]->isValueDependent())
        ExprBits.ValueDependent = true;
      if (Args[i]->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (Args[i]->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;

      this->Args[i] = Args[i];
    }
  }
}

LambdaCapture::LambdaCapture(SourceLocation Loc, bool Implicit,
                             LambdaCaptureKind Kind, VarDecl *Var,
                             SourceLocation EllipsisLoc)
    : DeclAndBits(Var, 0), Loc(Loc), EllipsisLoc(EllipsisLoc) {
  unsigned Bits = 0;
  if (Implicit)
    Bits |= Capture_Implicit;

  switch (Kind) {
  case LCK_StarThis:
    Bits |= Capture_ByCopy;
    LLVM_FALLTHROUGH;
  case LCK_This:
    assert(!Var && "'this' capture cannot have a variable!");
    Bits |= Capture_This;
    break;

  case LCK_ByCopy:
    Bits |= Capture_ByCopy;
    LLVM_FALLTHROUGH;
  case LCK_ByRef:
    assert(Var && "capture must have a variable!");
    break;
  case LCK_VLAType:
    assert(!Var && "VLA type capture cannot have a variable!");
    break;
  }
  DeclAndBits.setInt(Bits);
}

LambdaCaptureKind LambdaCapture::getCaptureKind() const {
  if (capturesVLAType())
    return LCK_VLAType;
  bool CapByCopy = DeclAndBits.getInt() & Capture_ByCopy;
  if (capturesThis())
    return CapByCopy ? LCK_StarThis : LCK_This;
  return CapByCopy ? LCK_ByCopy : LCK_ByRef;
}

LambdaExpr::LambdaExpr(QualType T, SourceRange IntroducerRange,
                       LambdaCaptureDefault CaptureDefault,
                       SourceLocation CaptureDefaultLoc,
                       ArrayRef<LambdaCapture> Captures, bool ExplicitParams,
                       bool ExplicitResultType, ArrayRef<Expr *> CaptureInits,
                       SourceLocation ClosingBrace,
                       bool ContainsUnexpandedParameterPack)
    : Expr(LambdaExprClass, T, VK_RValue, OK_Ordinary, T->isDependentType(),
           T->isDependentType(), T->isDependentType(),
           ContainsUnexpandedParameterPack),
      IntroducerRange(IntroducerRange), CaptureDefaultLoc(CaptureDefaultLoc),
      NumCaptures(Captures.size()), CaptureDefault(CaptureDefault),
      ExplicitParams(ExplicitParams), ExplicitResultType(ExplicitResultType),
      ClosingBrace(ClosingBrace) {
  assert(CaptureInits.size() == Captures.size() && "Wrong number of arguments");
  CXXRecordDecl *Class = getLambdaClass();
  CXXRecordDecl::LambdaDefinitionData &Data = Class->getLambdaData();

  // FIXME: Propagate "has unexpanded parameter pack" bit.

  // Copy captures.
  const ASTContext &Context = Class->getASTContext();
  Data.NumCaptures = NumCaptures;
  Data.NumExplicitCaptures = 0;
  Data.Captures =
      (LambdaCapture *)Context.Allocate(sizeof(LambdaCapture) * NumCaptures);
  LambdaCapture *ToCapture = Data.Captures;
  for (unsigned I = 0, N = Captures.size(); I != N; ++I) {
    if (Captures[I].isExplicit())
      ++Data.NumExplicitCaptures;

    *ToCapture++ = Captures[I];
  }

  // Copy initialization expressions for the non-static data members.
  Stmt **Stored = getStoredStmts();
  for (unsigned I = 0, N = CaptureInits.size(); I != N; ++I)
    *Stored++ = CaptureInits[I];

  // Copy the body of the lambda.
  *Stored++ = getCallOperator()->getBody();
}

LambdaExpr *LambdaExpr::Create(
    const ASTContext &Context, CXXRecordDecl *Class,
    SourceRange IntroducerRange, LambdaCaptureDefault CaptureDefault,
    SourceLocation CaptureDefaultLoc, ArrayRef<LambdaCapture> Captures,
    bool ExplicitParams, bool ExplicitResultType, ArrayRef<Expr *> CaptureInits,
    SourceLocation ClosingBrace, bool ContainsUnexpandedParameterPack) {
  // Determine the type of the expression (i.e., the type of the
  // function object we're creating).
  QualType T = Context.getTypeDeclType(Class);

  unsigned Size = totalSizeToAlloc<Stmt *>(Captures.size() + 1);
  void *Mem = Context.Allocate(Size);
  return new (Mem)
      LambdaExpr(T, IntroducerRange, CaptureDefault, CaptureDefaultLoc,
                 Captures, ExplicitParams, ExplicitResultType, CaptureInits,
                 ClosingBrace, ContainsUnexpandedParameterPack);
}

LambdaExpr *LambdaExpr::CreateDeserialized(const ASTContext &C,
                                           unsigned NumCaptures) {
  unsigned Size = totalSizeToAlloc<Stmt *>(NumCaptures + 1);
  void *Mem = C.Allocate(Size);
  return new (Mem) LambdaExpr(EmptyShell(), NumCaptures);
}

bool LambdaExpr::isInitCapture(const LambdaCapture *C) const {
  return (C->capturesVariable() && C->getCapturedVar()->isInitCapture() &&
          (getCallOperator() == C->getCapturedVar()->getDeclContext()));
}

LambdaExpr::capture_iterator LambdaExpr::capture_begin() const {
  return getLambdaClass()->getLambdaData().Captures;
}

LambdaExpr::capture_iterator LambdaExpr::capture_end() const {
  return capture_begin() + NumCaptures;
}

LambdaExpr::capture_range LambdaExpr::captures() const {
  return capture_range(capture_begin(), capture_end());
}

LambdaExpr::capture_iterator LambdaExpr::explicit_capture_begin() const {
  return capture_begin();
}

LambdaExpr::capture_iterator LambdaExpr::explicit_capture_end() const {
  struct CXXRecordDecl::LambdaDefinitionData &Data
    = getLambdaClass()->getLambdaData();
  return Data.Captures + Data.NumExplicitCaptures;
}

LambdaExpr::capture_range LambdaExpr::explicit_captures() const {
  return capture_range(explicit_capture_begin(), explicit_capture_end());
}

LambdaExpr::capture_iterator LambdaExpr::implicit_capture_begin() const {
  return explicit_capture_end();
}

LambdaExpr::capture_iterator LambdaExpr::implicit_capture_end() const {
  return capture_end();
}

LambdaExpr::capture_range LambdaExpr::implicit_captures() const {
  return capture_range(implicit_capture_begin(), implicit_capture_end());
}

CXXRecordDecl *LambdaExpr::getLambdaClass() const {
  return getType()->getAsCXXRecordDecl();
}

CXXMethodDecl *LambdaExpr::getCallOperator() const {
  CXXRecordDecl *Record = getLambdaClass();
  return Record->getLambdaCallOperator();
}

TemplateParameterList *LambdaExpr::getTemplateParameterList() const {
  CXXRecordDecl *Record = getLambdaClass();
  return Record->getGenericLambdaTemplateParameterList();

}

CompoundStmt *LambdaExpr::getBody() const {
  // FIXME: this mutation in getBody is bogus. It should be
  // initialized in ASTStmtReader::VisitLambdaExpr, but for reasons I
  // don't understand, that doesn't work.
  if (!getStoredStmts()[NumCaptures])
    *const_cast<Stmt **>(&getStoredStmts()[NumCaptures]) =
        getCallOperator()->getBody();

  return static_cast<CompoundStmt *>(getStoredStmts()[NumCaptures]);
}

bool LambdaExpr::isMutable() const {
  return !getCallOperator()->isConst();
}

ExprWithCleanups::ExprWithCleanups(Expr *subexpr,
                                   bool CleanupsHaveSideEffects,
                                   ArrayRef<CleanupObject> objects)
    : Expr(ExprWithCleanupsClass, subexpr->getType(),
           subexpr->getValueKind(), subexpr->getObjectKind(),
           subexpr->isTypeDependent(), subexpr->isValueDependent(),
           subexpr->isInstantiationDependent(),
           subexpr->containsUnexpandedParameterPack()),
      SubExpr(subexpr) {
  ExprWithCleanupsBits.CleanupsHaveSideEffects = CleanupsHaveSideEffects;
  ExprWithCleanupsBits.NumObjects = objects.size();
  for (unsigned i = 0, e = objects.size(); i != e; ++i)
    getTrailingObjects<CleanupObject>()[i] = objects[i];
}

ExprWithCleanups *ExprWithCleanups::Create(const ASTContext &C, Expr *subexpr,
                                           bool CleanupsHaveSideEffects,
                                           ArrayRef<CleanupObject> objects) {
  void *buffer = C.Allocate(totalSizeToAlloc<CleanupObject>(objects.size()),
                            alignof(ExprWithCleanups));
  return new (buffer)
      ExprWithCleanups(subexpr, CleanupsHaveSideEffects, objects);
}

ExprWithCleanups::ExprWithCleanups(EmptyShell empty, unsigned numObjects)
    : Expr(ExprWithCleanupsClass, empty) {
  ExprWithCleanupsBits.NumObjects = numObjects;
}

ExprWithCleanups *ExprWithCleanups::Create(const ASTContext &C,
                                           EmptyShell empty,
                                           unsigned numObjects) {
  void *buffer = C.Allocate(totalSizeToAlloc<CleanupObject>(numObjects),
                            alignof(ExprWithCleanups));
  return new (buffer) ExprWithCleanups(empty, numObjects);
}

CXXUnresolvedConstructExpr::CXXUnresolvedConstructExpr(TypeSourceInfo *Type,
                                                 SourceLocation LParenLoc,
                                                 ArrayRef<Expr*> Args,
                                                 SourceLocation RParenLoc)
    : Expr(CXXUnresolvedConstructExprClass,
           Type->getType().getNonReferenceType(),
           (Type->getType()->isLValueReferenceType()
                ? VK_LValue
                : Type->getType()->isRValueReferenceType() ? VK_XValue
                                                           : VK_RValue),
           OK_Ordinary,
           Type->getType()->isDependentType() ||
               Type->getType()->getContainedDeducedType(),
           true, true, Type->getType()->containsUnexpandedParameterPack()),
      Type(Type), LParenLoc(LParenLoc), RParenLoc(RParenLoc),
      NumArgs(Args.size()) {
  auto **StoredArgs = getTrailingObjects<Expr *>();
  for (unsigned I = 0; I != Args.size(); ++I) {
    if (Args[I]->containsUnexpandedParameterPack())
      ExprBits.ContainsUnexpandedParameterPack = true;

    StoredArgs[I] = Args[I];
  }
}

CXXUnresolvedConstructExpr *
CXXUnresolvedConstructExpr::Create(const ASTContext &C,
                                   TypeSourceInfo *Type,
                                   SourceLocation LParenLoc,
                                   ArrayRef<Expr*> Args,
                                   SourceLocation RParenLoc) {
  void *Mem = C.Allocate(totalSizeToAlloc<Expr *>(Args.size()));
  return new (Mem) CXXUnresolvedConstructExpr(Type, LParenLoc, Args, RParenLoc);
}

CXXUnresolvedConstructExpr *
CXXUnresolvedConstructExpr::CreateEmpty(const ASTContext &C, unsigned NumArgs) {
  Stmt::EmptyShell Empty;
  void *Mem = C.Allocate(totalSizeToAlloc<Expr *>(NumArgs));
  return new (Mem) CXXUnresolvedConstructExpr(Empty, NumArgs);
}

SourceLocation CXXUnresolvedConstructExpr::getBeginLoc() const {
  return Type->getTypeLoc().getBeginLoc();
}

CXXDependentScopeMemberExpr::CXXDependentScopeMemberExpr(
    const ASTContext &C, Expr *Base, QualType BaseType, bool IsArrow,
    SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
    SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
    DeclarationNameInfo MemberNameInfo,
    const TemplateArgumentListInfo *TemplateArgs)
    : Expr(CXXDependentScopeMemberExprClass, C.DependentTy, VK_LValue,
           OK_Ordinary, true, true, true,
           ((Base && Base->containsUnexpandedParameterPack()) ||
            (QualifierLoc &&
             QualifierLoc.getNestedNameSpecifier()
                 ->containsUnexpandedParameterPack()) ||
            MemberNameInfo.containsUnexpandedParameterPack())),
      Base(Base), BaseType(BaseType), IsArrow(IsArrow),
      HasTemplateKWAndArgsInfo(TemplateArgs != nullptr ||
                               TemplateKWLoc.isValid()),
      OperatorLoc(OperatorLoc), QualifierLoc(QualifierLoc),
      FirstQualifierFoundInScope(FirstQualifierFoundInScope),
      MemberNameInfo(MemberNameInfo) {
  if (TemplateArgs) {
    bool Dependent = true;
    bool InstantiationDependent = true;
    bool ContainsUnexpandedParameterPack = false;
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc, *TemplateArgs, getTrailingObjects<TemplateArgumentLoc>(),
        Dependent, InstantiationDependent, ContainsUnexpandedParameterPack);
    if (ContainsUnexpandedParameterPack)
      ExprBits.ContainsUnexpandedParameterPack = true;
  } else if (TemplateKWLoc.isValid()) {
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc);
  }
}

CXXDependentScopeMemberExpr *
CXXDependentScopeMemberExpr::Create(const ASTContext &C,
                                Expr *Base, QualType BaseType, bool IsArrow,
                                SourceLocation OperatorLoc,
                                NestedNameSpecifierLoc QualifierLoc,
                                SourceLocation TemplateKWLoc,
                                NamedDecl *FirstQualifierFoundInScope,
                                DeclarationNameInfo MemberNameInfo,
                                const TemplateArgumentListInfo *TemplateArgs) {
  bool HasTemplateKWAndArgsInfo = TemplateArgs || TemplateKWLoc.isValid();
  unsigned NumTemplateArgs = TemplateArgs ? TemplateArgs->size() : 0;
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, NumTemplateArgs);

  void *Mem = C.Allocate(Size, alignof(CXXDependentScopeMemberExpr));
  return new (Mem) CXXDependentScopeMemberExpr(C, Base, BaseType,
                                               IsArrow, OperatorLoc,
                                               QualifierLoc,
                                               TemplateKWLoc,
                                               FirstQualifierFoundInScope,
                                               MemberNameInfo, TemplateArgs);
}

CXXDependentScopeMemberExpr *
CXXDependentScopeMemberExpr::CreateEmpty(const ASTContext &C,
                                         bool HasTemplateKWAndArgsInfo,
                                         unsigned NumTemplateArgs) {
  assert(NumTemplateArgs == 0 || HasTemplateKWAndArgsInfo);
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, NumTemplateArgs);
  void *Mem = C.Allocate(Size, alignof(CXXDependentScopeMemberExpr));
  auto *E =
      new (Mem) CXXDependentScopeMemberExpr(C, nullptr, QualType(),
                                            false, SourceLocation(),
                                            NestedNameSpecifierLoc(),
                                            SourceLocation(), nullptr,
                                            DeclarationNameInfo(), nullptr);
  E->HasTemplateKWAndArgsInfo = HasTemplateKWAndArgsInfo;
  return E;
}

bool CXXDependentScopeMemberExpr::isImplicitAccess() const {
  if (!Base)
    return true;

  return cast<Expr>(Base)->isImplicitCXXThis();
}

static bool hasOnlyNonStaticMemberFunctions(UnresolvedSetIterator begin,
                                            UnresolvedSetIterator end) {
  do {
    NamedDecl *decl = *begin;
    if (isa<UnresolvedUsingValueDecl>(decl))
      return false;

    // Unresolved member expressions should only contain methods and
    // method templates.
    if (cast<CXXMethodDecl>(decl->getUnderlyingDecl()->getAsFunction())
            ->isStatic())
      return false;
  } while (++begin != end);

  return true;
}

UnresolvedMemberExpr::UnresolvedMemberExpr(const ASTContext &C,
                                           bool HasUnresolvedUsing,
                                           Expr *Base, QualType BaseType,
                                           bool IsArrow,
                                           SourceLocation OperatorLoc,
                                           NestedNameSpecifierLoc QualifierLoc,
                                           SourceLocation TemplateKWLoc,
                                   const DeclarationNameInfo &MemberNameInfo,
                                   const TemplateArgumentListInfo *TemplateArgs,
                                           UnresolvedSetIterator Begin,
                                           UnresolvedSetIterator End)
    : OverloadExpr(
          UnresolvedMemberExprClass, C, QualifierLoc, TemplateKWLoc,
          MemberNameInfo, TemplateArgs, Begin, End,
          // Dependent
          ((Base && Base->isTypeDependent()) || BaseType->isDependentType()),
          ((Base && Base->isInstantiationDependent()) ||
           BaseType->isInstantiationDependentType()),
          // Contains unexpanded parameter pack
          ((Base && Base->containsUnexpandedParameterPack()) ||
           BaseType->containsUnexpandedParameterPack())),
      IsArrow(IsArrow), HasUnresolvedUsing(HasUnresolvedUsing), Base(Base),
      BaseType(BaseType), OperatorLoc(OperatorLoc) {
  // Check whether all of the members are non-static member functions,
  // and if so, mark give this bound-member type instead of overload type.
  if (hasOnlyNonStaticMemberFunctions(Begin, End))
    setType(C.BoundMemberTy);
}

bool UnresolvedMemberExpr::isImplicitAccess() const {
  if (!Base)
    return true;

  return cast<Expr>(Base)->isImplicitCXXThis();
}

UnresolvedMemberExpr *UnresolvedMemberExpr::Create(
    const ASTContext &C, bool HasUnresolvedUsing, Expr *Base, QualType BaseType,
    bool IsArrow, SourceLocation OperatorLoc,
    NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
    const DeclarationNameInfo &MemberNameInfo,
    const TemplateArgumentListInfo *TemplateArgs, UnresolvedSetIterator Begin,
    UnresolvedSetIterator End) {
  bool HasTemplateKWAndArgsInfo = TemplateArgs || TemplateKWLoc.isValid();
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, TemplateArgs ? TemplateArgs->size() : 0);

  void *Mem = C.Allocate(Size, alignof(UnresolvedMemberExpr));
  return new (Mem) UnresolvedMemberExpr(
      C, HasUnresolvedUsing, Base, BaseType, IsArrow, OperatorLoc, QualifierLoc,
      TemplateKWLoc, MemberNameInfo, TemplateArgs, Begin, End);
}

UnresolvedMemberExpr *
UnresolvedMemberExpr::CreateEmpty(const ASTContext &C,
                                  bool HasTemplateKWAndArgsInfo,
                                  unsigned NumTemplateArgs) {
  assert(NumTemplateArgs == 0 || HasTemplateKWAndArgsInfo);
  std::size_t Size =
      totalSizeToAlloc<ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasTemplateKWAndArgsInfo, NumTemplateArgs);

  void *Mem = C.Allocate(Size, alignof(UnresolvedMemberExpr));
  auto *E = new (Mem) UnresolvedMemberExpr(EmptyShell());
  E->HasTemplateKWAndArgsInfo = HasTemplateKWAndArgsInfo;
  return E;
}

CXXRecordDecl *UnresolvedMemberExpr::getNamingClass() const {
  // Unlike for UnresolvedLookupExpr, it is very easy to re-derive this.

  // If there was a nested name specifier, it names the naming class.
  // It can't be dependent: after all, we were actually able to do the
  // lookup.
  CXXRecordDecl *Record = nullptr;
  auto *NNS = getQualifier();
  if (NNS && NNS->getKind() != NestedNameSpecifier::Super) {
    const Type *T = getQualifier()->getAsType();
    assert(T && "qualifier in member expression does not name type");
    Record = T->getAsCXXRecordDecl();
    assert(Record && "qualifier in member expression does not name record");
  }
  // Otherwise the naming class must have been the base class.
  else {
    QualType BaseType = getBaseType().getNonReferenceType();
    if (isArrow()) {
      const auto *PT = BaseType->getAs<PointerType>();
      assert(PT && "base of arrow member access is not pointer");
      BaseType = PT->getPointeeType();
    }

    Record = BaseType->getAsCXXRecordDecl();
    assert(Record && "base of member expression does not name record");
  }

  return Record;
}

SizeOfPackExpr *
SizeOfPackExpr::Create(ASTContext &Context, SourceLocation OperatorLoc,
                       NamedDecl *Pack, SourceLocation PackLoc,
                       SourceLocation RParenLoc,
                       Optional<unsigned> Length,
                       ArrayRef<TemplateArgument> PartialArgs) {
  void *Storage =
      Context.Allocate(totalSizeToAlloc<TemplateArgument>(PartialArgs.size()));
  return new (Storage) SizeOfPackExpr(Context.getSizeType(), OperatorLoc, Pack,
                                      PackLoc, RParenLoc, Length, PartialArgs);
}

SizeOfPackExpr *SizeOfPackExpr::CreateDeserialized(ASTContext &Context,
                                                   unsigned NumPartialArgs) {
  void *Storage =
      Context.Allocate(totalSizeToAlloc<TemplateArgument>(NumPartialArgs));
  return new (Storage) SizeOfPackExpr(EmptyShell(), NumPartialArgs);
}

SubstNonTypeTemplateParmPackExpr::
SubstNonTypeTemplateParmPackExpr(QualType T,
                                 ExprValueKind ValueKind,
                                 NonTypeTemplateParmDecl *Param,
                                 SourceLocation NameLoc,
                                 const TemplateArgument &ArgPack)
    : Expr(SubstNonTypeTemplateParmPackExprClass, T, ValueKind, OK_Ordinary,
           true, true, true, true),
      Param(Param), Arguments(ArgPack.pack_begin()),
      NumArguments(ArgPack.pack_size()), NameLoc(NameLoc) {}

TemplateArgument SubstNonTypeTemplateParmPackExpr::getArgumentPack() const {
  return TemplateArgument(llvm::makeArrayRef(Arguments, NumArguments));
}

FunctionParmPackExpr::FunctionParmPackExpr(QualType T, ParmVarDecl *ParamPack,
                                           SourceLocation NameLoc,
                                           unsigned NumParams,
                                           ParmVarDecl *const *Params)
    : Expr(FunctionParmPackExprClass, T, VK_LValue, OK_Ordinary, true, true,
           true, true),
      ParamPack(ParamPack), NameLoc(NameLoc), NumParameters(NumParams) {
  if (Params)
    std::uninitialized_copy(Params, Params + NumParams,
                            getTrailingObjects<ParmVarDecl *>());
}

FunctionParmPackExpr *
FunctionParmPackExpr::Create(const ASTContext &Context, QualType T,
                             ParmVarDecl *ParamPack, SourceLocation NameLoc,
                             ArrayRef<ParmVarDecl *> Params) {
  return new (Context.Allocate(totalSizeToAlloc<ParmVarDecl *>(Params.size())))
      FunctionParmPackExpr(T, ParamPack, NameLoc, Params.size(), Params.data());
}

FunctionParmPackExpr *
FunctionParmPackExpr::CreateEmpty(const ASTContext &Context,
                                  unsigned NumParams) {
  return new (Context.Allocate(totalSizeToAlloc<ParmVarDecl *>(NumParams)))
      FunctionParmPackExpr(QualType(), nullptr, SourceLocation(), 0, nullptr);
}

void MaterializeTemporaryExpr::setExtendingDecl(const ValueDecl *ExtendedBy,
                                                unsigned ManglingNumber) {
  // We only need extra state if we have to remember more than just the Stmt.
  if (!ExtendedBy)
    return;

  // We may need to allocate extra storage for the mangling number and the
  // extended-by ValueDecl.
  if (!State.is<ExtraState *>()) {
    auto *ES = new (ExtendedBy->getASTContext()) ExtraState;
    ES->Temporary = State.get<Stmt *>();
    State = ES;
  }

  auto ES = State.get<ExtraState *>();
  ES->ExtendingDecl = ExtendedBy;
  ES->ManglingNumber = ManglingNumber;
}

TypeTraitExpr::TypeTraitExpr(QualType T, SourceLocation Loc, TypeTrait Kind,
                             ArrayRef<TypeSourceInfo *> Args,
                             SourceLocation RParenLoc,
                             bool Value)
    : Expr(TypeTraitExprClass, T, VK_RValue, OK_Ordinary,
           /*TypeDependent=*/false,
           /*ValueDependent=*/false,
           /*InstantiationDependent=*/false,
           /*ContainsUnexpandedParameterPack=*/false),
      Loc(Loc), RParenLoc(RParenLoc) {
  TypeTraitExprBits.Kind = Kind;
  TypeTraitExprBits.Value = Value;
  TypeTraitExprBits.NumArgs = Args.size();

  auto **ToArgs = getTrailingObjects<TypeSourceInfo *>();

  for (unsigned I = 0, N = Args.size(); I != N; ++I) {
    if (Args[I]->getType()->isDependentType())
      setValueDependent(true);
    if (Args[I]->getType()->isInstantiationDependentType())
      setInstantiationDependent(true);
    if (Args[I]->getType()->containsUnexpandedParameterPack())
      setContainsUnexpandedParameterPack(true);

    ToArgs[I] = Args[I];
  }
}

TypeTraitExpr *TypeTraitExpr::Create(const ASTContext &C, QualType T,
                                     SourceLocation Loc,
                                     TypeTrait Kind,
                                     ArrayRef<TypeSourceInfo *> Args,
                                     SourceLocation RParenLoc,
                                     bool Value) {
  void *Mem = C.Allocate(totalSizeToAlloc<TypeSourceInfo *>(Args.size()));
  return new (Mem) TypeTraitExpr(T, Loc, Kind, Args, RParenLoc, Value);
}

TypeTraitExpr *TypeTraitExpr::CreateDeserialized(const ASTContext &C,
                                                 unsigned NumArgs) {
  void *Mem = C.Allocate(totalSizeToAlloc<TypeSourceInfo *>(NumArgs));
  return new (Mem) TypeTraitExpr(EmptyShell());
}

void ArrayTypeTraitExpr::anchor() {}