xref: /freebsd-src/contrib/llvm-project/clang/lib/AST/Expr.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)

//===--- Expr.cpp - Expression AST Node Implementation --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the Expr class and subclasses.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/Expr.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/ComputeDependence.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/DependenceFlags.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/IgnoreExpr.h"
#include "clang/AST/Mangle.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/LiteralSupport.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cstring>
#include <optional>
using namespace clang;

const Expr *Expr::getBestDynamicClassTypeExpr() const {
  const Expr *E = this;
  while (true) {
    E = E->IgnoreParenBaseCasts();

    // Follow the RHS of a comma operator.
    if (auto *BO = dyn_cast<BinaryOperator>(E)) {
      if (BO->getOpcode() == BO_Comma) {
        E = BO->getRHS();
        continue;
      }
    }

    // Step into initializer for materialized temporaries.
    if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E)) {
      E = MTE->getSubExpr();
      continue;
    }

    break;
  }

  return E;
}

const CXXRecordDecl *Expr::getBestDynamicClassType() const {
  const Expr *E = getBestDynamicClassTypeExpr();
  QualType DerivedType = E->getType();
  if (const PointerType *PTy = DerivedType->getAs<PointerType>())
    DerivedType = PTy->getPointeeType();

  if (DerivedType->isDependentType())
    return nullptr;

  const RecordType *Ty = DerivedType->castAs<RecordType>();
  Decl *D = Ty->getDecl();
  return cast<CXXRecordDecl>(D);
}

const Expr *Expr::skipRValueSubobjectAdjustments(
    SmallVectorImpl<const Expr *> &CommaLHSs,
    SmallVectorImpl<SubobjectAdjustment> &Adjustments) const {
  const Expr *E = this;
  while (true) {
    E = E->IgnoreParens();

    if (const auto *CE = dyn_cast<CastExpr>(E)) {
      if ((CE->getCastKind() == CK_DerivedToBase ||
           CE->getCastKind() == CK_UncheckedDerivedToBase) &&
          E->getType()->isRecordType()) {
        E = CE->getSubExpr();
        const auto *Derived =
            cast<CXXRecordDecl>(E->getType()->castAs<RecordType>()->getDecl());
        Adjustments.push_back(SubobjectAdjustment(CE, Derived));
        continue;
      }

      if (CE->getCastKind() == CK_NoOp) {
        E = CE->getSubExpr();
        continue;
      }
    } else if (const auto *ME = dyn_cast<MemberExpr>(E)) {
      if (!ME->isArrow()) {
        assert(ME->getBase()->getType()->getAsRecordDecl());
        if (const auto *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
          if (!Field->isBitField() && !Field->getType()->isReferenceType()) {
            E = ME->getBase();
            Adjustments.push_back(SubobjectAdjustment(Field));
            continue;
          }
        }
      }
    } else if (const auto *BO = dyn_cast<BinaryOperator>(E)) {
      if (BO->getOpcode() == BO_PtrMemD) {
        assert(BO->getRHS()->isPRValue());
        E = BO->getLHS();
        const auto *MPT = BO->getRHS()->getType()->getAs<MemberPointerType>();
        Adjustments.push_back(SubobjectAdjustment(MPT, BO->getRHS()));
        continue;
      }
      if (BO->getOpcode() == BO_Comma) {
        CommaLHSs.push_back(BO->getLHS());
        E = BO->getRHS();
        continue;
      }
    }

    // Nothing changed.
    break;
  }
  return E;
}

bool Expr::isKnownToHaveBooleanValue(bool Semantic) const {
  const Expr *E = IgnoreParens();

  // If this value has _Bool type, it is obvious 0/1.
  if (E->getType()->isBooleanType()) return true;
  // If this is a non-scalar-integer type, we don't care enough to try.
  if (!E->getType()->isIntegralOrEnumerationType()) return false;

  if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
    switch (UO->getOpcode()) {
    case UO_Plus:
      return UO->getSubExpr()->isKnownToHaveBooleanValue(Semantic);
    case UO_LNot:
      return true;
    default:
      return false;
    }
  }

  // Only look through implicit casts.  If the user writes
  // '(int) (a && b)' treat it as an arbitrary int.
  // FIXME: Should we look through any cast expression in !Semantic mode?
  if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E))
    return CE->getSubExpr()->isKnownToHaveBooleanValue(Semantic);

  if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
    switch (BO->getOpcode()) {
    default: return false;
    case BO_LT:   // Relational operators.
    case BO_GT:
    case BO_LE:
    case BO_GE:
    case BO_EQ:   // Equality operators.
    case BO_NE:
    case BO_LAnd: // AND operator.
    case BO_LOr:  // Logical OR operator.
      return true;

    case BO_And:  // Bitwise AND operator.
    case BO_Xor:  // Bitwise XOR operator.
    case BO_Or:   // Bitwise OR operator.
      // Handle things like (x==2)|(y==12).
      return BO->getLHS()->isKnownToHaveBooleanValue(Semantic) &&
             BO->getRHS()->isKnownToHaveBooleanValue(Semantic);

    case BO_Comma:
    case BO_Assign:
      return BO->getRHS()->isKnownToHaveBooleanValue(Semantic);
    }
  }

  if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E))
    return CO->getTrueExpr()->isKnownToHaveBooleanValue(Semantic) &&
           CO->getFalseExpr()->isKnownToHaveBooleanValue(Semantic);

  if (isa<ObjCBoolLiteralExpr>(E))
    return true;

  if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
    return OVE->getSourceExpr()->isKnownToHaveBooleanValue(Semantic);

  if (const FieldDecl *FD = E->getSourceBitField())
    if (!Semantic && FD->getType()->isUnsignedIntegerType() &&
        !FD->getBitWidth()->isValueDependent() &&
        FD->getBitWidthValue(FD->getASTContext()) == 1)
      return true;

  return false;
}

bool Expr::isFlexibleArrayMemberLike(
    ASTContext &Ctx,
    LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel,
    bool IgnoreTemplateOrMacroSubstitution) const {
  const Expr *E = IgnoreParens();
  const Decl *D = nullptr;

  if (const auto *ME = dyn_cast<MemberExpr>(E))
    D = ME->getMemberDecl();
  else if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
    D = DRE->getDecl();
  else if (const auto *IRE = dyn_cast<ObjCIvarRefExpr>(E))
    D = IRE->getDecl();

  return Decl::isFlexibleArrayMemberLike(Ctx, D, E->getType(),
                                         StrictFlexArraysLevel,
                                         IgnoreTemplateOrMacroSubstitution);
}

const ValueDecl *
Expr::getAsBuiltinConstantDeclRef(const ASTContext &Context) const {
  Expr::EvalResult Eval;

  if (EvaluateAsConstantExpr(Eval, Context)) {
    APValue &Value = Eval.Val;

    if (Value.isMemberPointer())
      return Value.getMemberPointerDecl();

    if (Value.isLValue() && Value.getLValueOffset().isZero())
      return Value.getLValueBase().dyn_cast<const ValueDecl *>();
  }

  return nullptr;
}

// Amusing macro metaprogramming hack: check whether a class provides
// a more specific implementation of getExprLoc().
//
// See also Stmt.cpp:{getBeginLoc(),getEndLoc()}.
namespace {
  /// This implementation is used when a class provides a custom
  /// implementation of getExprLoc.
  template <class E, class T>
  SourceLocation getExprLocImpl(const Expr *expr,
                                SourceLocation (T::*v)() const) {
    return static_cast<const E*>(expr)->getExprLoc();
  }

  /// This implementation is used when a class doesn't provide
  /// a custom implementation of getExprLoc.  Overload resolution
  /// should pick it over the implementation above because it's
  /// more specialized according to function template partial ordering.
  template <class E>
  SourceLocation getExprLocImpl(const Expr *expr,
                                SourceLocation (Expr::*v)() const) {
    return static_cast<const E *>(expr)->getBeginLoc();
  }
}

QualType Expr::getEnumCoercedType(const ASTContext &Ctx) const {
  if (isa<EnumType>(getType()))
    return getType();
  if (const auto *ECD = getEnumConstantDecl()) {
    const auto *ED = cast<EnumDecl>(ECD->getDeclContext());
    if (ED->isCompleteDefinition())
      return Ctx.getTypeDeclType(ED);
  }
  return getType();
}

SourceLocation Expr::getExprLoc() const {
  switch (getStmtClass()) {
  case Stmt::NoStmtClass: llvm_unreachable("statement without class");
#define ABSTRACT_STMT(type)
#define STMT(type, base) \
  case Stmt::type##Class: break;
#define EXPR(type, base) \
  case Stmt::type##Class: return getExprLocImpl<type>(this, &type::getExprLoc);
#include "clang/AST/StmtNodes.inc"
  }
  llvm_unreachable("unknown expression kind");
}

//===----------------------------------------------------------------------===//
// Primary Expressions.
//===----------------------------------------------------------------------===//

static void AssertResultStorageKind(ConstantResultStorageKind Kind) {
  assert((Kind == ConstantResultStorageKind::APValue ||
          Kind == ConstantResultStorageKind::Int64 ||
          Kind == ConstantResultStorageKind::None) &&
         "Invalid StorageKind Value");
  (void)Kind;
}

ConstantResultStorageKind ConstantExpr::getStorageKind(const APValue &Value) {
  switch (Value.getKind()) {
  case APValue::None:
  case APValue::Indeterminate:
    return ConstantResultStorageKind::None;
  case APValue::Int:
    if (!Value.getInt().needsCleanup())
      return ConstantResultStorageKind::Int64;
    [[fallthrough]];
  default:
    return ConstantResultStorageKind::APValue;
  }
}

ConstantResultStorageKind
ConstantExpr::getStorageKind(const Type *T, const ASTContext &Context) {
  if (T->isIntegralOrEnumerationType() && Context.getTypeInfo(T).Width <= 64)
    return ConstantResultStorageKind::Int64;
  return ConstantResultStorageKind::APValue;
}

ConstantExpr::ConstantExpr(Expr *SubExpr, ConstantResultStorageKind StorageKind,
                           bool IsImmediateInvocation)
    : FullExpr(ConstantExprClass, SubExpr) {
  ConstantExprBits.ResultKind = llvm::to_underlying(StorageKind);
  ConstantExprBits.APValueKind = APValue::None;
  ConstantExprBits.IsUnsigned = false;
  ConstantExprBits.BitWidth = 0;
  ConstantExprBits.HasCleanup = false;
  ConstantExprBits.IsImmediateInvocation = IsImmediateInvocation;

  if (StorageKind == ConstantResultStorageKind::APValue)
    ::new (getTrailingObjects<APValue>()) APValue();
}

ConstantExpr *ConstantExpr::Create(const ASTContext &Context, Expr *E,
                                   ConstantResultStorageKind StorageKind,
                                   bool IsImmediateInvocation) {
  assert(!isa<ConstantExpr>(E));
  AssertResultStorageKind(StorageKind);

  unsigned Size = totalSizeToAlloc<APValue, uint64_t>(
      StorageKind == ConstantResultStorageKind::APValue,
      StorageKind == ConstantResultStorageKind::Int64);
  void *Mem = Context.Allocate(Size, alignof(ConstantExpr));
  return new (Mem) ConstantExpr(E, StorageKind, IsImmediateInvocation);
}

ConstantExpr *ConstantExpr::Create(const ASTContext &Context, Expr *E,
                                   const APValue &Result) {
  ConstantResultStorageKind StorageKind = getStorageKind(Result);
  ConstantExpr *Self = Create(Context, E, StorageKind);
  Self->SetResult(Result, Context);
  return Self;
}

ConstantExpr::ConstantExpr(EmptyShell Empty,
                           ConstantResultStorageKind StorageKind)
    : FullExpr(ConstantExprClass, Empty) {
  ConstantExprBits.ResultKind = llvm::to_underlying(StorageKind);

  if (StorageKind == ConstantResultStorageKind::APValue)
    ::new (getTrailingObjects<APValue>()) APValue();
}

ConstantExpr *ConstantExpr::CreateEmpty(const ASTContext &Context,
                                        ConstantResultStorageKind StorageKind) {
  AssertResultStorageKind(StorageKind);

  unsigned Size = totalSizeToAlloc<APValue, uint64_t>(
      StorageKind == ConstantResultStorageKind::APValue,
      StorageKind == ConstantResultStorageKind::Int64);
  void *Mem = Context.Allocate(Size, alignof(ConstantExpr));
  return new (Mem) ConstantExpr(EmptyShell(), StorageKind);
}

void ConstantExpr::MoveIntoResult(APValue &Value, const ASTContext &Context) {
  assert((unsigned)getStorageKind(Value) <= ConstantExprBits.ResultKind &&
         "Invalid storage for this value kind");
  ConstantExprBits.APValueKind = Value.getKind();
  switch (getResultStorageKind()) {
  case ConstantResultStorageKind::None:
    return;
  case ConstantResultStorageKind::Int64:
    Int64Result() = *Value.getInt().getRawData();
    ConstantExprBits.BitWidth = Value.getInt().getBitWidth();
    ConstantExprBits.IsUnsigned = Value.getInt().isUnsigned();
    return;
  case ConstantResultStorageKind::APValue:
    if (!ConstantExprBits.HasCleanup && Value.needsCleanup()) {
      ConstantExprBits.HasCleanup = true;
      Context.addDestruction(&APValueResult());
    }
    APValueResult() = std::move(Value);
    return;
  }
  llvm_unreachable("Invalid ResultKind Bits");
}

llvm::APSInt ConstantExpr::getResultAsAPSInt() const {
  switch (getResultStorageKind()) {
  case ConstantResultStorageKind::APValue:
    return APValueResult().getInt();
  case ConstantResultStorageKind::Int64:
    return llvm::APSInt(llvm::APInt(ConstantExprBits.BitWidth, Int64Result()),
                        ConstantExprBits.IsUnsigned);
  default:
    llvm_unreachable("invalid Accessor");
  }
}

APValue ConstantExpr::getAPValueResult() const {

  switch (getResultStorageKind()) {
  case ConstantResultStorageKind::APValue:
    return APValueResult();
  case ConstantResultStorageKind::Int64:
    return APValue(
        llvm::APSInt(llvm::APInt(ConstantExprBits.BitWidth, Int64Result()),
                     ConstantExprBits.IsUnsigned));
  case ConstantResultStorageKind::None:
    if (ConstantExprBits.APValueKind == APValue::Indeterminate)
      return APValue::IndeterminateValue();
    return APValue();
  }
  llvm_unreachable("invalid ResultKind");
}

DeclRefExpr::DeclRefExpr(const ASTContext &Ctx, ValueDecl *D,
                         bool RefersToEnclosingVariableOrCapture, QualType T,
                         ExprValueKind VK, SourceLocation L,
                         const DeclarationNameLoc &LocInfo,
                         NonOdrUseReason NOUR)
    : Expr(DeclRefExprClass, T, VK, OK_Ordinary), D(D), DNLoc(LocInfo) {
  DeclRefExprBits.HasQualifier = false;
  DeclRefExprBits.HasTemplateKWAndArgsInfo = false;
  DeclRefExprBits.HasFoundDecl = false;
  DeclRefExprBits.HadMultipleCandidates = false;
  DeclRefExprBits.RefersToEnclosingVariableOrCapture =
      RefersToEnclosingVariableOrCapture;
  DeclRefExprBits.CapturedByCopyInLambdaWithExplicitObjectParameter = false;
  DeclRefExprBits.NonOdrUseReason = NOUR;
  DeclRefExprBits.IsImmediateEscalating = false;
  DeclRefExprBits.Loc = L;
  setDependence(computeDependence(this, Ctx));
}

DeclRefExpr::DeclRefExpr(const ASTContext &Ctx,
                         NestedNameSpecifierLoc QualifierLoc,
                         SourceLocation TemplateKWLoc, ValueDecl *D,
                         bool RefersToEnclosingVariableOrCapture,
                         const DeclarationNameInfo &NameInfo, NamedDecl *FoundD,
                         const TemplateArgumentListInfo *TemplateArgs,
                         QualType T, ExprValueKind VK, NonOdrUseReason NOUR)
    : Expr(DeclRefExprClass, T, VK, OK_Ordinary), D(D),
      DNLoc(NameInfo.getInfo()) {
  DeclRefExprBits.Loc = NameInfo.getLoc();
  DeclRefExprBits.HasQualifier = QualifierLoc ? 1 : 0;
  if (QualifierLoc)
    new (getTrailingObjects<NestedNameSpecifierLoc>())
        NestedNameSpecifierLoc(QualifierLoc);
  DeclRefExprBits.HasFoundDecl = FoundD ? 1 : 0;
  if (FoundD)
    *getTrailingObjects<NamedDecl *>() = FoundD;
  DeclRefExprBits.HasTemplateKWAndArgsInfo
    = (TemplateArgs || TemplateKWLoc.isValid()) ? 1 : 0;
  DeclRefExprBits.RefersToEnclosingVariableOrCapture =
      RefersToEnclosingVariableOrCapture;
  DeclRefExprBits.CapturedByCopyInLambdaWithExplicitObjectParameter = false;
  DeclRefExprBits.NonOdrUseReason = NOUR;
  if (TemplateArgs) {
    auto Deps = TemplateArgumentDependence::None;
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc, *TemplateArgs, getTrailingObjects<TemplateArgumentLoc>(),
        Deps);
    assert(!(Deps & TemplateArgumentDependence::Dependent) &&
           "built a DeclRefExpr with dependent template args");
  } else if (TemplateKWLoc.isValid()) {
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc);
  }
  DeclRefExprBits.IsImmediateEscalating = false;
  DeclRefExprBits.HadMultipleCandidates = 0;
  setDependence(computeDependence(this, Ctx));
}

DeclRefExpr *DeclRefExpr::Create(const ASTContext &Context,
                                 NestedNameSpecifierLoc QualifierLoc,
                                 SourceLocation TemplateKWLoc, ValueDecl *D,
                                 bool RefersToEnclosingVariableOrCapture,
                                 SourceLocation NameLoc, QualType T,
                                 ExprValueKind VK, NamedDecl *FoundD,
                                 const TemplateArgumentListInfo *TemplateArgs,
                                 NonOdrUseReason NOUR) {
  return Create(Context, QualifierLoc, TemplateKWLoc, D,
                RefersToEnclosingVariableOrCapture,
                DeclarationNameInfo(D->getDeclName(), NameLoc),
                T, VK, FoundD, TemplateArgs, NOUR);
}

DeclRefExpr *DeclRefExpr::Create(const ASTContext &Context,
                                 NestedNameSpecifierLoc QualifierLoc,
                                 SourceLocation TemplateKWLoc, ValueDecl *D,
                                 bool RefersToEnclosingVariableOrCapture,
                                 const DeclarationNameInfo &NameInfo,
                                 QualType T, ExprValueKind VK,
                                 NamedDecl *FoundD,
                                 const TemplateArgumentListInfo *TemplateArgs,
                                 NonOdrUseReason NOUR) {
  // Filter out cases where the found Decl is the same as the value refenenced.
  if (D == FoundD)
    FoundD = nullptr;

  bool HasTemplateKWAndArgsInfo = TemplateArgs || TemplateKWLoc.isValid();
  std::size_t Size =
      totalSizeToAlloc<NestedNameSpecifierLoc, NamedDecl *,
                       ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          QualifierLoc ? 1 : 0, FoundD ? 1 : 0,
          HasTemplateKWAndArgsInfo ? 1 : 0,
          TemplateArgs ? TemplateArgs->size() : 0);

  void *Mem = Context.Allocate(Size, alignof(DeclRefExpr));
  return new (Mem) DeclRefExpr(Context, QualifierLoc, TemplateKWLoc, D,
                               RefersToEnclosingVariableOrCapture, NameInfo,
                               FoundD, TemplateArgs, T, VK, NOUR);
}

DeclRefExpr *DeclRefExpr::CreateEmpty(const ASTContext &Context,
                                      bool HasQualifier,
                                      bool HasFoundDecl,
                                      bool HasTemplateKWAndArgsInfo,
                                      unsigned NumTemplateArgs) {
  assert(NumTemplateArgs == 0 || HasTemplateKWAndArgsInfo);
  std::size_t Size =
      totalSizeToAlloc<NestedNameSpecifierLoc, NamedDecl *,
                       ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasQualifier ? 1 : 0, HasFoundDecl ? 1 : 0, HasTemplateKWAndArgsInfo,
          NumTemplateArgs);
  void *Mem = Context.Allocate(Size, alignof(DeclRefExpr));
  return new (Mem) DeclRefExpr(EmptyShell());
}

void DeclRefExpr::setDecl(ValueDecl *NewD) {
  D = NewD;
  if (getType()->isUndeducedType())
    setType(NewD->getType());
  setDependence(computeDependence(this, NewD->getASTContext()));
}

SourceLocation DeclRefExpr::getBeginLoc() const {
  if (hasQualifier())
    return getQualifierLoc().getBeginLoc();
  return getNameInfo().getBeginLoc();
}
SourceLocation DeclRefExpr::getEndLoc() const {
  if (hasExplicitTemplateArgs())
    return getRAngleLoc();
  return getNameInfo().getEndLoc();
}

SYCLUniqueStableNameExpr::SYCLUniqueStableNameExpr(SourceLocation OpLoc,
                                                   SourceLocation LParen,
                                                   SourceLocation RParen,
                                                   QualType ResultTy,
                                                   TypeSourceInfo *TSI)
    : Expr(SYCLUniqueStableNameExprClass, ResultTy, VK_PRValue, OK_Ordinary),
      OpLoc(OpLoc), LParen(LParen), RParen(RParen) {
  setTypeSourceInfo(TSI);
  setDependence(computeDependence(this));
}

SYCLUniqueStableNameExpr::SYCLUniqueStableNameExpr(EmptyShell Empty,
                                                   QualType ResultTy)
    : Expr(SYCLUniqueStableNameExprClass, ResultTy, VK_PRValue, OK_Ordinary) {}

SYCLUniqueStableNameExpr *
SYCLUniqueStableNameExpr::Create(const ASTContext &Ctx, SourceLocation OpLoc,
                                 SourceLocation LParen, SourceLocation RParen,
                                 TypeSourceInfo *TSI) {
  QualType ResultTy = Ctx.getPointerType(Ctx.CharTy.withConst());
  return new (Ctx)
      SYCLUniqueStableNameExpr(OpLoc, LParen, RParen, ResultTy, TSI);
}

SYCLUniqueStableNameExpr *
SYCLUniqueStableNameExpr::CreateEmpty(const ASTContext &Ctx) {
  QualType ResultTy = Ctx.getPointerType(Ctx.CharTy.withConst());
  return new (Ctx) SYCLUniqueStableNameExpr(EmptyShell(), ResultTy);
}

std::string SYCLUniqueStableNameExpr::ComputeName(ASTContext &Context) const {
  return SYCLUniqueStableNameExpr::ComputeName(Context,
                                               getTypeSourceInfo()->getType());
}

std::string SYCLUniqueStableNameExpr::ComputeName(ASTContext &Context,
                                                  QualType Ty) {
  auto MangleCallback = [](ASTContext &Ctx,
                           const NamedDecl *ND) -> std::optional<unsigned> {
    if (const auto *RD = dyn_cast<CXXRecordDecl>(ND))
      return RD->getDeviceLambdaManglingNumber();
    return std::nullopt;
  };

  std::unique_ptr<MangleContext> Ctx{ItaniumMangleContext::create(
      Context, Context.getDiagnostics(), MangleCallback)};

  std::string Buffer;
  Buffer.reserve(128);
  llvm::raw_string_ostream Out(Buffer);
  Ctx->mangleCanonicalTypeName(Ty, Out);

  return Out.str();
}

PredefinedExpr::PredefinedExpr(SourceLocation L, QualType FNTy,
                               PredefinedIdentKind IK, bool IsTransparent,
                               StringLiteral *SL)
    : Expr(PredefinedExprClass, FNTy, VK_LValue, OK_Ordinary) {
  PredefinedExprBits.Kind = llvm::to_underlying(IK);
  assert((getIdentKind() == IK) &&
         "IdentKind do not fit in PredefinedExprBitfields!");
  bool HasFunctionName = SL != nullptr;
  PredefinedExprBits.HasFunctionName = HasFunctionName;
  PredefinedExprBits.IsTransparent = IsTransparent;
  PredefinedExprBits.Loc = L;
  if (HasFunctionName)
    setFunctionName(SL);
  setDependence(computeDependence(this));
}

PredefinedExpr::PredefinedExpr(EmptyShell Empty, bool HasFunctionName)
    : Expr(PredefinedExprClass, Empty) {
  PredefinedExprBits.HasFunctionName = HasFunctionName;
}

PredefinedExpr *PredefinedExpr::Create(const ASTContext &Ctx, SourceLocation L,
                                       QualType FNTy, PredefinedIdentKind IK,
                                       bool IsTransparent, StringLiteral *SL) {
  bool HasFunctionName = SL != nullptr;
  void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(HasFunctionName),
                           alignof(PredefinedExpr));
  return new (Mem) PredefinedExpr(L, FNTy, IK, IsTransparent, SL);
}

PredefinedExpr *PredefinedExpr::CreateEmpty(const ASTContext &Ctx,
                                            bool HasFunctionName) {
  void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(HasFunctionName),
                           alignof(PredefinedExpr));
  return new (Mem) PredefinedExpr(EmptyShell(), HasFunctionName);
}

StringRef PredefinedExpr::getIdentKindName(PredefinedIdentKind IK) {
  switch (IK) {
  case PredefinedIdentKind::Func:
    return "__func__";
  case PredefinedIdentKind::Function:
    return "__FUNCTION__";
  case PredefinedIdentKind::FuncDName:
    return "__FUNCDNAME__";
  case PredefinedIdentKind::LFunction:
    return "L__FUNCTION__";
  case PredefinedIdentKind::PrettyFunction:
    return "__PRETTY_FUNCTION__";
  case PredefinedIdentKind::FuncSig:
    return "__FUNCSIG__";
  case PredefinedIdentKind::LFuncSig:
    return "L__FUNCSIG__";
  case PredefinedIdentKind::PrettyFunctionNoVirtual:
    break;
  }
  llvm_unreachable("Unknown ident kind for PredefinedExpr");
}

// FIXME: Maybe this should use DeclPrinter with a special "print predefined
// expr" policy instead.
std::string PredefinedExpr::ComputeName(PredefinedIdentKind IK,
                                        const Decl *CurrentDecl,
                                        bool ForceElaboratedPrinting) {
  ASTContext &Context = CurrentDecl->getASTContext();

  if (IK == PredefinedIdentKind::FuncDName) {
    if (const NamedDecl *ND = dyn_cast<NamedDecl>(CurrentDecl)) {
      std::unique_ptr<MangleContext> MC;
      MC.reset(Context.createMangleContext());

      if (MC->shouldMangleDeclName(ND)) {
        SmallString<256> Buffer;
        llvm::raw_svector_ostream Out(Buffer);
        GlobalDecl GD;
        if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(ND))
          GD = GlobalDecl(CD, Ctor_Base);
        else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(ND))
          GD = GlobalDecl(DD, Dtor_Base);
        else if (ND->hasAttr<CUDAGlobalAttr>())
          GD = GlobalDecl(cast<FunctionDecl>(ND));
        else
          GD = GlobalDecl(ND);
        MC->mangleName(GD, Out);

        if (!Buffer.empty() && Buffer.front() == '\01')
          return std::string(Buffer.substr(1));
        return std::string(Buffer);
      }
      return std::string(ND->getIdentifier()->getName());
    }
    return "";
  }
  if (isa<BlockDecl>(CurrentDecl)) {
    // For blocks we only emit something if it is enclosed in a function
    // For top-level block we'd like to include the name of variable, but we
    // don't have it at this point.
    auto DC = CurrentDecl->getDeclContext();
    if (DC->isFileContext())
      return "";

    SmallString<256> Buffer;
    llvm::raw_svector_ostream Out(Buffer);
    if (auto *DCBlock = dyn_cast<BlockDecl>(DC))
      // For nested blocks, propagate up to the parent.
      Out << ComputeName(IK, DCBlock);
    else if (auto *DCDecl = dyn_cast<Decl>(DC))
      Out << ComputeName(IK, DCDecl) << "_block_invoke";
    return std::string(Out.str());
  }
  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurrentDecl)) {
    const auto &LO = Context.getLangOpts();
    bool IsFuncOrFunctionInNonMSVCCompatEnv =
        ((IK == PredefinedIdentKind::Func ||
          IK == PredefinedIdentKind ::Function) &&
         !LO.MSVCCompat);
    bool IsLFunctionInMSVCCommpatEnv =
        IK == PredefinedIdentKind::LFunction && LO.MSVCCompat;
    bool IsFuncOrFunctionOrLFunctionOrFuncDName =
        IK != PredefinedIdentKind::PrettyFunction &&
        IK != PredefinedIdentKind::PrettyFunctionNoVirtual &&
        IK != PredefinedIdentKind::FuncSig &&
        IK != PredefinedIdentKind::LFuncSig;
    if ((ForceElaboratedPrinting &&
         (IsFuncOrFunctionInNonMSVCCompatEnv || IsLFunctionInMSVCCommpatEnv)) ||
        (!ForceElaboratedPrinting && IsFuncOrFunctionOrLFunctionOrFuncDName))
      return FD->getNameAsString();

    SmallString<256> Name;
    llvm::raw_svector_ostream Out(Name);

    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
      if (MD->isVirtual() && IK != PredefinedIdentKind::PrettyFunctionNoVirtual)
        Out << "virtual ";
      if (MD->isStatic())
        Out << "static ";
    }

    class PrettyCallbacks final : public PrintingCallbacks {
    public:
      PrettyCallbacks(const LangOptions &LO) : LO(LO) {}
      std::string remapPath(StringRef Path) const override {
        SmallString<128> p(Path);
        LO.remapPathPrefix(p);
        return std::string(p);
      }

    private:
      const LangOptions &LO;
    };
    PrintingPolicy Policy(Context.getLangOpts());
    PrettyCallbacks PrettyCB(Context.getLangOpts());
    Policy.Callbacks = &PrettyCB;
    if (IK == PredefinedIdentKind::Function && ForceElaboratedPrinting)
      Policy.SuppressTagKeyword = !LO.MSVCCompat;
    std::string Proto;
    llvm::raw_string_ostream POut(Proto);

    const FunctionDecl *Decl = FD;
    if (const FunctionDecl* Pattern = FD->getTemplateInstantiationPattern())
      Decl = Pattern;
    const FunctionType *AFT = Decl->getType()->getAs<FunctionType>();
    const FunctionProtoType *FT = nullptr;
    if (FD->hasWrittenPrototype())
      FT = dyn_cast<FunctionProtoType>(AFT);

    if (IK == PredefinedIdentKind::FuncSig ||
        IK == PredefinedIdentKind::LFuncSig) {
      switch (AFT->getCallConv()) {
      case CC_C: POut << "__cdecl "; break;
      case CC_X86StdCall: POut << "__stdcall "; break;
      case CC_X86FastCall: POut << "__fastcall "; break;
      case CC_X86ThisCall: POut << "__thiscall "; break;
      case CC_X86VectorCall: POut << "__vectorcall "; break;
      case CC_X86RegCall: POut << "__regcall "; break;
      // Only bother printing the conventions that MSVC knows about.
      default: break;
      }
    }

    FD->printQualifiedName(POut, Policy);

    if (IK == PredefinedIdentKind::Function) {
      POut.flush();
      Out << Proto;
      return std::string(Name);
    }

    POut << "(";
    if (FT) {
      for (unsigned i = 0, e = Decl->getNumParams(); i != e; ++i) {
        if (i) POut << ", ";
        POut << Decl->getParamDecl(i)->getType().stream(Policy);
      }

      if (FT->isVariadic()) {
        if (FD->getNumParams()) POut << ", ";
        POut << "...";
      } else if ((IK == PredefinedIdentKind::FuncSig ||
                  IK == PredefinedIdentKind::LFuncSig ||
                  !Context.getLangOpts().CPlusPlus) &&
                 !Decl->getNumParams()) {
        POut << "void";
      }
    }
    POut << ")";

    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
      assert(FT && "We must have a written prototype in this case.");
      if (FT->isConst())
        POut << " const";
      if (FT->isVolatile())
        POut << " volatile";
      RefQualifierKind Ref = MD->getRefQualifier();
      if (Ref == RQ_LValue)
        POut << " &";
      else if (Ref == RQ_RValue)
        POut << " &&";
    }

    typedef SmallVector<const ClassTemplateSpecializationDecl *, 8> SpecsTy;
    SpecsTy Specs;
    const DeclContext *Ctx = FD->getDeclContext();
    while (isa_and_nonnull<NamedDecl>(Ctx)) {
      const ClassTemplateSpecializationDecl *Spec
                               = dyn_cast<ClassTemplateSpecializationDecl>(Ctx);
      if (Spec && !Spec->isExplicitSpecialization())
        Specs.push_back(Spec);
      Ctx = Ctx->getParent();
    }

    std::string TemplateParams;
    llvm::raw_string_ostream TOut(TemplateParams);
    for (const ClassTemplateSpecializationDecl *D : llvm::reverse(Specs)) {
      const TemplateParameterList *Params =
          D->getSpecializedTemplate()->getTemplateParameters();
      const TemplateArgumentList &Args = D->getTemplateArgs();
      assert(Params->size() == Args.size());
      for (unsigned i = 0, numParams = Params->size(); i != numParams; ++i) {
        StringRef Param = Params->getParam(i)->getName();
        if (Param.empty()) continue;
        TOut << Param << " = ";
        Args.get(i).print(Policy, TOut,
                          TemplateParameterList::shouldIncludeTypeForArgument(
                              Policy, Params, i));
        TOut << ", ";
      }
    }

    FunctionTemplateSpecializationInfo *FSI
                                          = FD->getTemplateSpecializationInfo();
    if (FSI && !FSI->isExplicitSpecialization()) {
      const TemplateParameterList* Params
                                  = FSI->getTemplate()->getTemplateParameters();
      const TemplateArgumentList* Args = FSI->TemplateArguments;
      assert(Params->size() == Args->size());
      for (unsigned i = 0, e = Params->size(); i != e; ++i) {
        StringRef Param = Params->getParam(i)->getName();
        if (Param.empty()) continue;
        TOut << Param << " = ";
        Args->get(i).print(Policy, TOut, /*IncludeType*/ true);
        TOut << ", ";
      }
    }

    TOut.flush();
    if (!TemplateParams.empty()) {
      // remove the trailing comma and space
      TemplateParams.resize(TemplateParams.size() - 2);
      POut << " [" << TemplateParams << "]";
    }

    POut.flush();

    // Print "auto" for all deduced return types. This includes C++1y return
    // type deduction and lambdas. For trailing return types resolve the
    // decltype expression. Otherwise print the real type when this is
    // not a constructor or destructor.
    if (isa<CXXMethodDecl>(FD) &&
         cast<CXXMethodDecl>(FD)->getParent()->isLambda())
      Proto = "auto " + Proto;
    else if (FT && FT->getReturnType()->getAs<DecltypeType>())
      FT->getReturnType()
          ->getAs<DecltypeType>()
          ->getUnderlyingType()
          .getAsStringInternal(Proto, Policy);
    else if (!isa<CXXConstructorDecl>(FD) && !isa<CXXDestructorDecl>(FD))
      AFT->getReturnType().getAsStringInternal(Proto, Policy);

    Out << Proto;

    return std::string(Name);
  }
  if (const CapturedDecl *CD = dyn_cast<CapturedDecl>(CurrentDecl)) {
    for (const DeclContext *DC = CD->getParent(); DC; DC = DC->getParent())
      // Skip to its enclosing function or method, but not its enclosing
      // CapturedDecl.
      if (DC->isFunctionOrMethod() && (DC->getDeclKind() != Decl::Captured)) {
        const Decl *D = Decl::castFromDeclContext(DC);
        return ComputeName(IK, D);
      }
    llvm_unreachable("CapturedDecl not inside a function or method");
  }
  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurrentDecl)) {
    SmallString<256> Name;
    llvm::raw_svector_ostream Out(Name);
    Out << (MD->isInstanceMethod() ? '-' : '+');
    Out << '[';

    // For incorrect code, there might not be an ObjCInterfaceDecl.  Do
    // a null check to avoid a crash.
    if (const ObjCInterfaceDecl *ID = MD->getClassInterface())
      Out << *ID;

    if (const ObjCCategoryImplDecl *CID =
        dyn_cast<ObjCCategoryImplDecl>(MD->getDeclContext()))
      Out << '(' << *CID << ')';

    Out <<  ' ';
    MD->getSelector().print(Out);
    Out <<  ']';

    return std::string(Name);
  }
  if (isa<TranslationUnitDecl>(CurrentDecl) &&
      IK == PredefinedIdentKind::PrettyFunction) {
    // __PRETTY_FUNCTION__ -> "top level", the others produce an empty string.
    return "top level";
  }
  return "";
}

void APNumericStorage::setIntValue(const ASTContext &C,
                                   const llvm::APInt &Val) {
  if (hasAllocation())
    C.Deallocate(pVal);

  BitWidth = Val.getBitWidth();
  unsigned NumWords = Val.getNumWords();
  const uint64_t* Words = Val.getRawData();
  if (NumWords > 1) {
    pVal = new (C) uint64_t[NumWords];
    std::copy(Words, Words + NumWords, pVal);
  } else if (NumWords == 1)
    VAL = Words[0];
  else
    VAL = 0;
}

IntegerLiteral::IntegerLiteral(const ASTContext &C, const llvm::APInt &V,
                               QualType type, SourceLocation l)
    : Expr(IntegerLiteralClass, type, VK_PRValue, OK_Ordinary), Loc(l) {
  assert(type->isIntegerType() && "Illegal type in IntegerLiteral");
  assert(V.getBitWidth() == C.getIntWidth(type) &&
         "Integer type is not the correct size for constant.");
  setValue(C, V);
  setDependence(ExprDependence::None);
}

IntegerLiteral *
IntegerLiteral::Create(const ASTContext &C, const llvm::APInt &V,
                       QualType type, SourceLocation l) {
  return new (C) IntegerLiteral(C, V, type, l);
}

IntegerLiteral *
IntegerLiteral::Create(const ASTContext &C, EmptyShell Empty) {
  return new (C) IntegerLiteral(Empty);
}

FixedPointLiteral::FixedPointLiteral(const ASTContext &C, const llvm::APInt &V,
                                     QualType type, SourceLocation l,
                                     unsigned Scale)
    : Expr(FixedPointLiteralClass, type, VK_PRValue, OK_Ordinary), Loc(l),
      Scale(Scale) {
  assert(type->isFixedPointType() && "Illegal type in FixedPointLiteral");
  assert(V.getBitWidth() == C.getTypeInfo(type).Width &&
         "Fixed point type is not the correct size for constant.");
  setValue(C, V);
  setDependence(ExprDependence::None);
}

FixedPointLiteral *FixedPointLiteral::CreateFromRawInt(const ASTContext &C,
                                                       const llvm::APInt &V,
                                                       QualType type,
                                                       SourceLocation l,
                                                       unsigned Scale) {
  return new (C) FixedPointLiteral(C, V, type, l, Scale);
}

FixedPointLiteral *FixedPointLiteral::Create(const ASTContext &C,
                                             EmptyShell Empty) {
  return new (C) FixedPointLiteral(Empty);
}

std::string FixedPointLiteral::getValueAsString(unsigned Radix) const {
  // Currently the longest decimal number that can be printed is the max for an
  // unsigned long _Accum: 4294967295.99999999976716935634613037109375
  // which is 43 characters.
  SmallString<64> S;
  FixedPointValueToString(
      S, llvm::APSInt::getUnsigned(getValue().getZExtValue()), Scale);
  return std::string(S);
}

void CharacterLiteral::print(unsigned Val, CharacterLiteralKind Kind,
                             raw_ostream &OS) {
  switch (Kind) {
  case CharacterLiteralKind::Ascii:
    break; // no prefix.
  case CharacterLiteralKind::Wide:
    OS << 'L';
    break;
  case CharacterLiteralKind::UTF8:
    OS << "u8";
    break;
  case CharacterLiteralKind::UTF16:
    OS << 'u';
    break;
  case CharacterLiteralKind::UTF32:
    OS << 'U';
    break;
  }

  StringRef Escaped = escapeCStyle<EscapeChar::Single>(Val);
  if (!Escaped.empty()) {
    OS << "'" << Escaped << "'";
  } else {
    // A character literal might be sign-extended, which
    // would result in an invalid \U escape sequence.
    // FIXME: multicharacter literals such as '\xFF\xFF\xFF\xFF'
    // are not correctly handled.
    if ((Val & ~0xFFu) == ~0xFFu && Kind == CharacterLiteralKind::Ascii)
      Val &= 0xFFu;
    if (Val < 256 && isPrintable((unsigned char)Val))
      OS << "'" << (char)Val << "'";
    else if (Val < 256)
      OS << "'\\x" << llvm::format("%02x", Val) << "'";
    else if (Val <= 0xFFFF)
      OS << "'\\u" << llvm::format("%04x", Val) << "'";
    else
      OS << "'\\U" << llvm::format("%08x", Val) << "'";
  }
}

FloatingLiteral::FloatingLiteral(const ASTContext &C, const llvm::APFloat &V,
                                 bool isexact, QualType Type, SourceLocation L)
    : Expr(FloatingLiteralClass, Type, VK_PRValue, OK_Ordinary), Loc(L) {
  setSemantics(V.getSemantics());
  FloatingLiteralBits.IsExact = isexact;
  setValue(C, V);
  setDependence(ExprDependence::None);
}

FloatingLiteral::FloatingLiteral(const ASTContext &C, EmptyShell Empty)
  : Expr(FloatingLiteralClass, Empty) {
  setRawSemantics(llvm::APFloatBase::S_IEEEhalf);
  FloatingLiteralBits.IsExact = false;
}

FloatingLiteral *
FloatingLiteral::Create(const ASTContext &C, const llvm::APFloat &V,
                        bool isexact, QualType Type, SourceLocation L) {
  return new (C) FloatingLiteral(C, V, isexact, Type, L);
}

FloatingLiteral *
FloatingLiteral::Create(const ASTContext &C, EmptyShell Empty) {
  return new (C) FloatingLiteral(C, Empty);
}

/// getValueAsApproximateDouble - This returns the value as an inaccurate
/// double.  Note that this may cause loss of precision, but is useful for
/// debugging dumps, etc.
double FloatingLiteral::getValueAsApproximateDouble() const {
  llvm::APFloat V = getValue();
  bool ignored;
  V.convert(llvm::APFloat::IEEEdouble(), llvm::APFloat::rmNearestTiesToEven,
            &ignored);
  return V.convertToDouble();
}

unsigned StringLiteral::mapCharByteWidth(TargetInfo const &Target,
                                         StringLiteralKind SK) {
  unsigned CharByteWidth = 0;
  switch (SK) {
  case StringLiteralKind::Ordinary:
  case StringLiteralKind::UTF8:
    CharByteWidth = Target.getCharWidth();
    break;
  case StringLiteralKind::Wide:
    CharByteWidth = Target.getWCharWidth();
    break;
  case StringLiteralKind::UTF16:
    CharByteWidth = Target.getChar16Width();
    break;
  case StringLiteralKind::UTF32:
    CharByteWidth = Target.getChar32Width();
    break;
  case StringLiteralKind::Unevaluated:
    return sizeof(char); // Host;
  }
  assert((CharByteWidth & 7) == 0 && "Assumes character size is byte multiple");
  CharByteWidth /= 8;
  assert((CharByteWidth == 1 || CharByteWidth == 2 || CharByteWidth == 4) &&
         "The only supported character byte widths are 1,2 and 4!");
  return CharByteWidth;
}

StringLiteral::StringLiteral(const ASTContext &Ctx, StringRef Str,
                             StringLiteralKind Kind, bool Pascal, QualType Ty,
                             const SourceLocation *Loc,
                             unsigned NumConcatenated)
    : Expr(StringLiteralClass, Ty, VK_LValue, OK_Ordinary) {

  unsigned Length = Str.size();

  StringLiteralBits.Kind = llvm::to_underlying(Kind);
  StringLiteralBits.NumConcatenated = NumConcatenated;

  if (Kind != StringLiteralKind::Unevaluated) {
    assert(Ctx.getAsConstantArrayType(Ty) &&
           "StringLiteral must be of constant array type!");
    unsigned CharByteWidth = mapCharByteWidth(Ctx.getTargetInfo(), Kind);
    unsigned ByteLength = Str.size();
    assert((ByteLength % CharByteWidth == 0) &&
           "The size of the data must be a multiple of CharByteWidth!");

    // Avoid the expensive division. The compiler should be able to figure it
    // out by itself. However as of clang 7, even with the appropriate
    // llvm_unreachable added just here, it is not able to do so.
    switch (CharByteWidth) {
    case 1:
      Length = ByteLength;
      break;
    case 2:
      Length = ByteLength / 2;
      break;
    case 4:
      Length = ByteLength / 4;
      break;
    default:
      llvm_unreachable("Unsupported character width!");
    }

    StringLiteralBits.CharByteWidth = CharByteWidth;
    StringLiteralBits.IsPascal = Pascal;
  } else {
    assert(!Pascal && "Can't make an unevaluated Pascal string");
    StringLiteralBits.CharByteWidth = 1;
    StringLiteralBits.IsPascal = false;
  }

  *getTrailingObjects<unsigned>() = Length;

  // Initialize the trailing array of SourceLocation.
  // This is safe since SourceLocation is POD-like.
  std::memcpy(getTrailingObjects<SourceLocation>(), Loc,
              NumConcatenated * sizeof(SourceLocation));

  // Initialize the trailing array of char holding the string data.
  std::memcpy(getTrailingObjects<char>(), Str.data(), Str.size());

  setDependence(ExprDependence::None);
}

StringLiteral::StringLiteral(EmptyShell Empty, unsigned NumConcatenated,
                             unsigned Length, unsigned CharByteWidth)
    : Expr(StringLiteralClass, Empty) {
  StringLiteralBits.CharByteWidth = CharByteWidth;
  StringLiteralBits.NumConcatenated = NumConcatenated;
  *getTrailingObjects<unsigned>() = Length;
}

StringLiteral *StringLiteral::Create(const ASTContext &Ctx, StringRef Str,
                                     StringLiteralKind Kind, bool Pascal,
                                     QualType Ty, const SourceLocation *Loc,
                                     unsigned NumConcatenated) {
  void *Mem = Ctx.Allocate(totalSizeToAlloc<unsigned, SourceLocation, char>(
                               1, NumConcatenated, Str.size()),
                           alignof(StringLiteral));
  return new (Mem)
      StringLiteral(Ctx, Str, Kind, Pascal, Ty, Loc, NumConcatenated);
}

StringLiteral *StringLiteral::CreateEmpty(const ASTContext &Ctx,
                                          unsigned NumConcatenated,
                                          unsigned Length,
                                          unsigned CharByteWidth) {
  void *Mem = Ctx.Allocate(totalSizeToAlloc<unsigned, SourceLocation, char>(
                               1, NumConcatenated, Length * CharByteWidth),
                           alignof(StringLiteral));
  return new (Mem)
      StringLiteral(EmptyShell(), NumConcatenated, Length, CharByteWidth);
}

void StringLiteral::outputString(raw_ostream &OS) const {
  switch (getKind()) {
  case StringLiteralKind::Unevaluated:
  case StringLiteralKind::Ordinary:
    break; // no prefix.
  case StringLiteralKind::Wide:
    OS << 'L';
    break;
  case StringLiteralKind::UTF8:
    OS << "u8";
    break;
  case StringLiteralKind::UTF16:
    OS << 'u';
    break;
  case StringLiteralKind::UTF32:
    OS << 'U';
    break;
  }
  OS << '"';
  static const char Hex[] = "0123456789ABCDEF";

  unsigned LastSlashX = getLength();
  for (unsigned I = 0, N = getLength(); I != N; ++I) {
    uint32_t Char = getCodeUnit(I);
    StringRef Escaped = escapeCStyle<EscapeChar::Double>(Char);
    if (Escaped.empty()) {
      // FIXME: Convert UTF-8 back to codepoints before rendering.

      // Convert UTF-16 surrogate pairs back to codepoints before rendering.
      // Leave invalid surrogates alone; we'll use \x for those.
      if (getKind() == StringLiteralKind::UTF16 && I != N - 1 &&
          Char >= 0xd800 && Char <= 0xdbff) {
        uint32_t Trail = getCodeUnit(I + 1);
        if (Trail >= 0xdc00 && Trail <= 0xdfff) {
          Char = 0x10000 + ((Char - 0xd800) << 10) + (Trail - 0xdc00);
          ++I;
        }
      }

      if (Char > 0xff) {
        // If this is a wide string, output characters over 0xff using \x
        // escapes. Otherwise, this is a UTF-16 or UTF-32 string, and Char is a
        // codepoint: use \x escapes for invalid codepoints.
        if (getKind() == StringLiteralKind::Wide ||
            (Char >= 0xd800 && Char <= 0xdfff) || Char >= 0x110000) {
          // FIXME: Is this the best way to print wchar_t?
          OS << "\\x";
          int Shift = 28;
          while ((Char >> Shift) == 0)
            Shift -= 4;
          for (/**/; Shift >= 0; Shift -= 4)
            OS << Hex[(Char >> Shift) & 15];
          LastSlashX = I;
          continue;
        }

        if (Char > 0xffff)
          OS << "\\U00"
             << Hex[(Char >> 20) & 15]
             << Hex[(Char >> 16) & 15];
        else
          OS << "\\u";
        OS << Hex[(Char >> 12) & 15]
           << Hex[(Char >>  8) & 15]
           << Hex[(Char >>  4) & 15]
           << Hex[(Char >>  0) & 15];
        continue;
      }

      // If we used \x... for the previous character, and this character is a
      // hexadecimal digit, prevent it being slurped as part of the \x.
      if (LastSlashX + 1 == I) {
        switch (Char) {
          case '0': case '1': case '2': case '3': case '4':
          case '5': case '6': case '7': case '8': case '9':
          case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
          case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
            OS << "\"\"";
        }
      }

      assert(Char <= 0xff &&
             "Characters above 0xff should already have been handled.");

      if (isPrintable(Char))
        OS << (char)Char;
      else  // Output anything hard as an octal escape.
        OS << '\\'
           << (char)('0' + ((Char >> 6) & 7))
           << (char)('0' + ((Char >> 3) & 7))
           << (char)('0' + ((Char >> 0) & 7));
    } else {
      // Handle some common non-printable cases to make dumps prettier.
      OS << Escaped;
    }
  }
  OS << '"';
}

/// getLocationOfByte - Return a source location that points to the specified
/// byte of this string literal.
///
/// Strings are amazingly complex.  They can be formed from multiple tokens and
/// can have escape sequences in them in addition to the usual trigraph and
/// escaped newline business.  This routine handles this complexity.
///
/// The *StartToken sets the first token to be searched in this function and
/// the *StartTokenByteOffset is the byte offset of the first token. Before
/// returning, it updates the *StartToken to the TokNo of the token being found
/// and sets *StartTokenByteOffset to the byte offset of the token in the
/// string.
/// Using these two parameters can reduce the time complexity from O(n^2) to
/// O(n) if one wants to get the location of byte for all the tokens in a
/// string.
///
SourceLocation
StringLiteral::getLocationOfByte(unsigned ByteNo, const SourceManager &SM,
                                 const LangOptions &Features,
                                 const TargetInfo &Target, unsigned *StartToken,
                                 unsigned *StartTokenByteOffset) const {
  assert((getKind() == StringLiteralKind::Ordinary ||
          getKind() == StringLiteralKind::UTF8 ||
          getKind() == StringLiteralKind::Unevaluated) &&
         "Only narrow string literals are currently supported");

  // Loop over all of the tokens in this string until we find the one that
  // contains the byte we're looking for.
  unsigned TokNo = 0;
  unsigned StringOffset = 0;
  if (StartToken)
    TokNo = *StartToken;
  if (StartTokenByteOffset) {
    StringOffset = *StartTokenByteOffset;
    ByteNo -= StringOffset;
  }
  while (true) {
    assert(TokNo < getNumConcatenated() && "Invalid byte number!");
    SourceLocation StrTokLoc = getStrTokenLoc(TokNo);

    // Get the spelling of the string so that we can get the data that makes up
    // the string literal, not the identifier for the macro it is potentially
    // expanded through.
    SourceLocation StrTokSpellingLoc = SM.getSpellingLoc(StrTokLoc);

    // Re-lex the token to get its length and original spelling.
    std::pair<FileID, unsigned> LocInfo =
        SM.getDecomposedLoc(StrTokSpellingLoc);
    bool Invalid = false;
    StringRef Buffer = SM.getBufferData(LocInfo.first, &Invalid);
    if (Invalid) {
      if (StartTokenByteOffset != nullptr)
        *StartTokenByteOffset = StringOffset;
      if (StartToken != nullptr)
        *StartToken = TokNo;
      return StrTokSpellingLoc;
    }

    const char *StrData = Buffer.data()+LocInfo.second;

    // Create a lexer starting at the beginning of this token.
    Lexer TheLexer(SM.getLocForStartOfFile(LocInfo.first), Features,
                   Buffer.begin(), StrData, Buffer.end());
    Token TheTok;
    TheLexer.LexFromRawLexer(TheTok);

    // Use the StringLiteralParser to compute the length of the string in bytes.
    StringLiteralParser SLP(TheTok, SM, Features, Target);
    unsigned TokNumBytes = SLP.GetStringLength();

    // If the byte is in this token, return the location of the byte.
    if (ByteNo < TokNumBytes ||
        (ByteNo == TokNumBytes && TokNo == getNumConcatenated() - 1)) {
      unsigned Offset = SLP.getOffsetOfStringByte(TheTok, ByteNo);

      // Now that we know the offset of the token in the spelling, use the
      // preprocessor to get the offset in the original source.
      if (StartTokenByteOffset != nullptr)
        *StartTokenByteOffset = StringOffset;
      if (StartToken != nullptr)
        *StartToken = TokNo;
      return Lexer::AdvanceToTokenCharacter(StrTokLoc, Offset, SM, Features);
    }

    // Move to the next string token.
    StringOffset += TokNumBytes;
    ++TokNo;
    ByteNo -= TokNumBytes;
  }
}

/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
/// corresponds to, e.g. "sizeof" or "[pre]++".
StringRef UnaryOperator::getOpcodeStr(Opcode Op) {
  switch (Op) {
#define UNARY_OPERATION(Name, Spelling) case UO_##Name: return Spelling;
#include "clang/AST/OperationKinds.def"
  }
  llvm_unreachable("Unknown unary operator");
}

UnaryOperatorKind
UnaryOperator::getOverloadedOpcode(OverloadedOperatorKind OO, bool Postfix) {
  switch (OO) {
  default: llvm_unreachable("No unary operator for overloaded function");
  case OO_PlusPlus:   return Postfix ? UO_PostInc : UO_PreInc;
  case OO_MinusMinus: return Postfix ? UO_PostDec : UO_PreDec;
  case OO_Amp:        return UO_AddrOf;
  case OO_Star:       return UO_Deref;
  case OO_Plus:       return UO_Plus;
  case OO_Minus:      return UO_Minus;
  case OO_Tilde:      return UO_Not;
  case OO_Exclaim:    return UO_LNot;
  case OO_Coawait:    return UO_Coawait;
  }
}

OverloadedOperatorKind UnaryOperator::getOverloadedOperator(Opcode Opc) {
  switch (Opc) {
  case UO_PostInc: case UO_PreInc: return OO_PlusPlus;
  case UO_PostDec: case UO_PreDec: return OO_MinusMinus;
  case UO_AddrOf: return OO_Amp;
  case UO_Deref: return OO_Star;
  case UO_Plus: return OO_Plus;
  case UO_Minus: return OO_Minus;
  case UO_Not: return OO_Tilde;
  case UO_LNot: return OO_Exclaim;
  case UO_Coawait: return OO_Coawait;
  default: return OO_None;
  }
}


//===----------------------------------------------------------------------===//
// Postfix Operators.
//===----------------------------------------------------------------------===//

CallExpr::CallExpr(StmtClass SC, Expr *Fn, ArrayRef<Expr *> PreArgs,
                   ArrayRef<Expr *> Args, QualType Ty, ExprValueKind VK,
                   SourceLocation RParenLoc, FPOptionsOverride FPFeatures,
                   unsigned MinNumArgs, ADLCallKind UsesADL)
    : Expr(SC, Ty, VK, OK_Ordinary), RParenLoc(RParenLoc) {
  NumArgs = std::max<unsigned>(Args.size(), MinNumArgs);
  unsigned NumPreArgs = PreArgs.size();
  CallExprBits.NumPreArgs = NumPreArgs;
  assert((NumPreArgs == getNumPreArgs()) && "NumPreArgs overflow!");

  unsigned OffsetToTrailingObjects = offsetToTrailingObjects(SC);
  CallExprBits.OffsetToTrailingObjects = OffsetToTrailingObjects;
  assert((CallExprBits.OffsetToTrailingObjects == OffsetToTrailingObjects) &&
         "OffsetToTrailingObjects overflow!");

  CallExprBits.UsesADL = static_cast<bool>(UsesADL);

  setCallee(Fn);
  for (unsigned I = 0; I != NumPreArgs; ++I)
    setPreArg(I, PreArgs[I]);
  for (unsigned I = 0; I != Args.size(); ++I)
    setArg(I, Args[I]);
  for (unsigned I = Args.size(); I != NumArgs; ++I)
    setArg(I, nullptr);

  this->computeDependence();

  CallExprBits.HasFPFeatures = FPFeatures.requiresTrailingStorage();
  if (hasStoredFPFeatures())
    setStoredFPFeatures(FPFeatures);
}

CallExpr::CallExpr(StmtClass SC, unsigned NumPreArgs, unsigned NumArgs,
                   bool HasFPFeatures, EmptyShell Empty)
    : Expr(SC, Empty), NumArgs(NumArgs) {
  CallExprBits.NumPreArgs = NumPreArgs;
  assert((NumPreArgs == getNumPreArgs()) && "NumPreArgs overflow!");

  unsigned OffsetToTrailingObjects = offsetToTrailingObjects(SC);
  CallExprBits.OffsetToTrailingObjects = OffsetToTrailingObjects;
  assert((CallExprBits.OffsetToTrailingObjects == OffsetToTrailingObjects) &&
         "OffsetToTrailingObjects overflow!");
  CallExprBits.HasFPFeatures = HasFPFeatures;
}

CallExpr *CallExpr::Create(const ASTContext &Ctx, Expr *Fn,
                           ArrayRef<Expr *> Args, QualType Ty, ExprValueKind VK,
                           SourceLocation RParenLoc,
                           FPOptionsOverride FPFeatures, unsigned MinNumArgs,
                           ADLCallKind UsesADL) {
  unsigned NumArgs = std::max<unsigned>(Args.size(), MinNumArgs);
  unsigned SizeOfTrailingObjects = CallExpr::sizeOfTrailingObjects(
      /*NumPreArgs=*/0, NumArgs, FPFeatures.requiresTrailingStorage());
  void *Mem =
      Ctx.Allocate(sizeof(CallExpr) + SizeOfTrailingObjects, alignof(CallExpr));
  return new (Mem) CallExpr(CallExprClass, Fn, /*PreArgs=*/{}, Args, Ty, VK,
                            RParenLoc, FPFeatures, MinNumArgs, UsesADL);
}

CallExpr *CallExpr::CreateTemporary(void *Mem, Expr *Fn, QualType Ty,
                                    ExprValueKind VK, SourceLocation RParenLoc,
                                    ADLCallKind UsesADL) {
  assert(!(reinterpret_cast<uintptr_t>(Mem) % alignof(CallExpr)) &&
         "Misaligned memory in CallExpr::CreateTemporary!");
  return new (Mem) CallExpr(CallExprClass, Fn, /*PreArgs=*/{}, /*Args=*/{}, Ty,
                            VK, RParenLoc, FPOptionsOverride(),
                            /*MinNumArgs=*/0, UsesADL);
}

CallExpr *CallExpr::CreateEmpty(const ASTContext &Ctx, unsigned NumArgs,
                                bool HasFPFeatures, EmptyShell Empty) {
  unsigned SizeOfTrailingObjects =
      CallExpr::sizeOfTrailingObjects(/*NumPreArgs=*/0, NumArgs, HasFPFeatures);
  void *Mem =
      Ctx.Allocate(sizeof(CallExpr) + SizeOfTrailingObjects, alignof(CallExpr));
  return new (Mem)
      CallExpr(CallExprClass, /*NumPreArgs=*/0, NumArgs, HasFPFeatures, Empty);
}

unsigned CallExpr::offsetToTrailingObjects(StmtClass SC) {
  switch (SC) {
  case CallExprClass:
    return sizeof(CallExpr);
  case CXXOperatorCallExprClass:
    return sizeof(CXXOperatorCallExpr);
  case CXXMemberCallExprClass:
    return sizeof(CXXMemberCallExpr);
  case UserDefinedLiteralClass:
    return sizeof(UserDefinedLiteral);
  case CUDAKernelCallExprClass:
    return sizeof(CUDAKernelCallExpr);
  default:
    llvm_unreachable("unexpected class deriving from CallExpr!");
  }
}

Decl *Expr::getReferencedDeclOfCallee() {
  Expr *CEE = IgnoreParenImpCasts();

  while (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(CEE))
    CEE = NTTP->getReplacement()->IgnoreParenImpCasts();

  // If we're calling a dereference, look at the pointer instead.
  while (true) {
    if (auto *BO = dyn_cast<BinaryOperator>(CEE)) {
      if (BO->isPtrMemOp()) {
        CEE = BO->getRHS()->IgnoreParenImpCasts();
        continue;
      }
    } else if (auto *UO = dyn_cast<UnaryOperator>(CEE)) {
      if (UO->getOpcode() == UO_Deref || UO->getOpcode() == UO_AddrOf ||
          UO->getOpcode() == UO_Plus) {
        CEE = UO->getSubExpr()->IgnoreParenImpCasts();
        continue;
      }
    }
    break;
  }

  if (auto *DRE = dyn_cast<DeclRefExpr>(CEE))
    return DRE->getDecl();
  if (auto *ME = dyn_cast<MemberExpr>(CEE))
    return ME->getMemberDecl();
  if (auto *BE = dyn_cast<BlockExpr>(CEE))
    return BE->getBlockDecl();

  return nullptr;
}

/// If this is a call to a builtin, return the builtin ID. If not, return 0.
unsigned CallExpr::getBuiltinCallee() const {
  const auto *FDecl = getDirectCallee();
  return FDecl ? FDecl->getBuiltinID() : 0;
}

bool CallExpr::isUnevaluatedBuiltinCall(const ASTContext &Ctx) const {
  if (unsigned BI = getBuiltinCallee())
    return Ctx.BuiltinInfo.isUnevaluated(BI);
  return false;
}

QualType CallExpr::getCallReturnType(const ASTContext &Ctx) const {
  const Expr *Callee = getCallee();
  QualType CalleeType = Callee->getType();
  if (const auto *FnTypePtr = CalleeType->getAs<PointerType>()) {
    CalleeType = FnTypePtr->getPointeeType();
  } else if (const auto *BPT = CalleeType->getAs<BlockPointerType>()) {
    CalleeType = BPT->getPointeeType();
  } else if (CalleeType->isSpecificPlaceholderType(BuiltinType::BoundMember)) {
    if (isa<CXXPseudoDestructorExpr>(Callee->IgnoreParens()))
      return Ctx.VoidTy;

    if (isa<UnresolvedMemberExpr>(Callee->IgnoreParens()))
      return Ctx.DependentTy;

    // This should never be overloaded and so should never return null.
    CalleeType = Expr::findBoundMemberType(Callee);
    assert(!CalleeType.isNull());
  } else if (CalleeType->isRecordType()) {
    // If the Callee is a record type, then it is a not-yet-resolved
    // dependent call to the call operator of that type.
    return Ctx.DependentTy;
  } else if (CalleeType->isDependentType() ||
             CalleeType->isSpecificPlaceholderType(BuiltinType::Overload)) {
    return Ctx.DependentTy;
  }

  const FunctionType *FnType = CalleeType->castAs<FunctionType>();
  return FnType->getReturnType();
}

const Attr *CallExpr::getUnusedResultAttr(const ASTContext &Ctx) const {
  // If the return type is a struct, union, or enum that is marked nodiscard,
  // then return the return type attribute.
  if (const TagDecl *TD = getCallReturnType(Ctx)->getAsTagDecl())
    if (const auto *A = TD->getAttr<WarnUnusedResultAttr>())
      return A;

  for (const auto *TD = getCallReturnType(Ctx)->getAs<TypedefType>(); TD;
       TD = TD->desugar()->getAs<TypedefType>())
    if (const auto *A = TD->getDecl()->getAttr<WarnUnusedResultAttr>())
      return A;

  // Otherwise, see if the callee is marked nodiscard and return that attribute
  // instead.
  const Decl *D = getCalleeDecl();
  return D ? D->getAttr<WarnUnusedResultAttr>() : nullptr;
}

SourceLocation CallExpr::getBeginLoc() const {
  if (const auto *OCE = dyn_cast<CXXOperatorCallExpr>(this))
    return OCE->getBeginLoc();

  SourceLocation begin = getCallee()->getBeginLoc();
  if (begin.isInvalid() && getNumArgs() > 0 && getArg(0))
    begin = getArg(0)->getBeginLoc();
  return begin;
}
SourceLocation CallExpr::getEndLoc() const {
  if (const auto *OCE = dyn_cast<CXXOperatorCallExpr>(this))
    return OCE->getEndLoc();

  SourceLocation end = getRParenLoc();
  if (end.isInvalid() && getNumArgs() > 0 && getArg(getNumArgs() - 1))
    end = getArg(getNumArgs() - 1)->getEndLoc();
  return end;
}

OffsetOfExpr *OffsetOfExpr::Create(const ASTContext &C, QualType type,
                                   SourceLocation OperatorLoc,
                                   TypeSourceInfo *tsi,
                                   ArrayRef<OffsetOfNode> comps,
                                   ArrayRef<Expr*> exprs,
                                   SourceLocation RParenLoc) {
  void *Mem = C.Allocate(
      totalSizeToAlloc<OffsetOfNode, Expr *>(comps.size(), exprs.size()));

  return new (Mem) OffsetOfExpr(C, type, OperatorLoc, tsi, comps, exprs,
                                RParenLoc);
}

OffsetOfExpr *OffsetOfExpr::CreateEmpty(const ASTContext &C,
                                        unsigned numComps, unsigned numExprs) {
  void *Mem =
      C.Allocate(totalSizeToAlloc<OffsetOfNode, Expr *>(numComps, numExprs));
  return new (Mem) OffsetOfExpr(numComps, numExprs);
}

OffsetOfExpr::OffsetOfExpr(const ASTContext &C, QualType type,
                           SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                           ArrayRef<OffsetOfNode> comps, ArrayRef<Expr *> exprs,
                           SourceLocation RParenLoc)
    : Expr(OffsetOfExprClass, type, VK_PRValue, OK_Ordinary),
      OperatorLoc(OperatorLoc), RParenLoc(RParenLoc), TSInfo(tsi),
      NumComps(comps.size()), NumExprs(exprs.size()) {
  for (unsigned i = 0; i != comps.size(); ++i)
    setComponent(i, comps[i]);
  for (unsigned i = 0; i != exprs.size(); ++i)
    setIndexExpr(i, exprs[i]);

  setDependence(computeDependence(this));
}

IdentifierInfo *OffsetOfNode::getFieldName() const {
  assert(getKind() == Field || getKind() == Identifier);
  if (getKind() == Field)
    return getField()->getIdentifier();

  return reinterpret_cast<IdentifierInfo *> (Data & ~(uintptr_t)Mask);
}

UnaryExprOrTypeTraitExpr::UnaryExprOrTypeTraitExpr(
    UnaryExprOrTypeTrait ExprKind, Expr *E, QualType resultType,
    SourceLocation op, SourceLocation rp)
    : Expr(UnaryExprOrTypeTraitExprClass, resultType, VK_PRValue, OK_Ordinary),
      OpLoc(op), RParenLoc(rp) {
  assert(ExprKind <= UETT_Last && "invalid enum value!");
  UnaryExprOrTypeTraitExprBits.Kind = ExprKind;
  assert(static_cast<unsigned>(ExprKind) == UnaryExprOrTypeTraitExprBits.Kind &&
         "UnaryExprOrTypeTraitExprBits.Kind overflow!");
  UnaryExprOrTypeTraitExprBits.IsType = false;
  Argument.Ex = E;
  setDependence(computeDependence(this));
}

MemberExpr::MemberExpr(Expr *Base, bool IsArrow, SourceLocation OperatorLoc,
                       NestedNameSpecifierLoc QualifierLoc,
                       SourceLocation TemplateKWLoc, ValueDecl *MemberDecl,
                       DeclAccessPair FoundDecl,
                       const DeclarationNameInfo &NameInfo,
                       const TemplateArgumentListInfo *TemplateArgs, QualType T,
                       ExprValueKind VK, ExprObjectKind OK,
                       NonOdrUseReason NOUR)
    : Expr(MemberExprClass, T, VK, OK), Base(Base), MemberDecl(MemberDecl),
      MemberDNLoc(NameInfo.getInfo()), MemberLoc(NameInfo.getLoc()) {
  assert(!NameInfo.getName() ||
         MemberDecl->getDeclName() == NameInfo.getName());
  MemberExprBits.IsArrow = IsArrow;
  MemberExprBits.HasQualifier = QualifierLoc.hasQualifier();
  MemberExprBits.HasFoundDecl =
      FoundDecl.getDecl() != MemberDecl ||
      FoundDecl.getAccess() != MemberDecl->getAccess();
  MemberExprBits.HasTemplateKWAndArgsInfo =
      TemplateArgs || TemplateKWLoc.isValid();
  MemberExprBits.HadMultipleCandidates = false;
  MemberExprBits.NonOdrUseReason = NOUR;
  MemberExprBits.OperatorLoc = OperatorLoc;

  if (hasQualifier())
    new (getTrailingObjects<NestedNameSpecifierLoc>())
        NestedNameSpecifierLoc(QualifierLoc);
  if (hasFoundDecl())
    *getTrailingObjects<DeclAccessPair>() = FoundDecl;
  if (TemplateArgs) {
    auto Deps = TemplateArgumentDependence::None;
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc, *TemplateArgs, getTrailingObjects<TemplateArgumentLoc>(),
        Deps);
  } else if (TemplateKWLoc.isValid()) {
    getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
        TemplateKWLoc);
  }
  setDependence(computeDependence(this));
}

MemberExpr *MemberExpr::Create(
    const ASTContext &C, Expr *Base, bool IsArrow, SourceLocation OperatorLoc,
    NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
    ValueDecl *MemberDecl, DeclAccessPair FoundDecl,
    DeclarationNameInfo NameInfo, const TemplateArgumentListInfo *TemplateArgs,
    QualType T, ExprValueKind VK, ExprObjectKind OK, NonOdrUseReason NOUR) {
  bool HasQualifier = QualifierLoc.hasQualifier();
  bool HasFoundDecl = FoundDecl.getDecl() != MemberDecl ||
                      FoundDecl.getAccess() != MemberDecl->getAccess();
  bool HasTemplateKWAndArgsInfo = TemplateArgs || TemplateKWLoc.isValid();
  std::size_t Size =
      totalSizeToAlloc<NestedNameSpecifierLoc, DeclAccessPair,
                       ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasQualifier, HasFoundDecl, HasTemplateKWAndArgsInfo,
          TemplateArgs ? TemplateArgs->size() : 0);

  void *Mem = C.Allocate(Size, alignof(MemberExpr));
  return new (Mem) MemberExpr(Base, IsArrow, OperatorLoc, QualifierLoc,
                              TemplateKWLoc, MemberDecl, FoundDecl, NameInfo,
                              TemplateArgs, T, VK, OK, NOUR);
}

MemberExpr *MemberExpr::CreateEmpty(const ASTContext &Context,
                                    bool HasQualifier, bool HasFoundDecl,
                                    bool HasTemplateKWAndArgsInfo,
                                    unsigned NumTemplateArgs) {
  assert((!NumTemplateArgs || HasTemplateKWAndArgsInfo) &&
         "template args but no template arg info?");
  std::size_t Size =
      totalSizeToAlloc<NestedNameSpecifierLoc, DeclAccessPair,
                       ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
          HasQualifier, HasFoundDecl, HasTemplateKWAndArgsInfo,
          NumTemplateArgs);
  void *Mem = Context.Allocate(Size, alignof(MemberExpr));
  return new (Mem) MemberExpr(EmptyShell());
}

void MemberExpr::setMemberDecl(ValueDecl *NewD) {
  MemberDecl = NewD;
  if (getType()->isUndeducedType())
    setType(NewD->getType());
  setDependence(computeDependence(this));
}

SourceLocation MemberExpr::getBeginLoc() const {
  if (isImplicitAccess()) {
    if (hasQualifier())
      return getQualifierLoc().getBeginLoc();
    return MemberLoc;
  }

  // FIXME: We don't want this to happen. Rather, we should be able to
  // detect all kinds of implicit accesses more cleanly.
  SourceLocation BaseStartLoc = getBase()->getBeginLoc();
  if (BaseStartLoc.isValid())
    return BaseStartLoc;
  return MemberLoc;
}
SourceLocation MemberExpr::getEndLoc() const {
  SourceLocation EndLoc = getMemberNameInfo().getEndLoc();
  if (hasExplicitTemplateArgs())
    EndLoc = getRAngleLoc();
  else if (EndLoc.isInvalid())
    EndLoc = getBase()->getEndLoc();
  return EndLoc;
}

bool CastExpr::CastConsistency() const {
  switch (getCastKind()) {
  case CK_DerivedToBase:
  case CK_UncheckedDerivedToBase:
  case CK_DerivedToBaseMemberPointer:
  case CK_BaseToDerived:
  case CK_BaseToDerivedMemberPointer:
    assert(!path_empty() && "Cast kind should have a base path!");
    break;

  case CK_CPointerToObjCPointerCast:
    assert(getType()->isObjCObjectPointerType());
    assert(getSubExpr()->getType()->isPointerType());
    goto CheckNoBasePath;

  case CK_BlockPointerToObjCPointerCast:
    assert(getType()->isObjCObjectPointerType());
    assert(getSubExpr()->getType()->isBlockPointerType());
    goto CheckNoBasePath;

  case CK_ReinterpretMemberPointer:
    assert(getType()->isMemberPointerType());
    assert(getSubExpr()->getType()->isMemberPointerType());
    goto CheckNoBasePath;

  case CK_BitCast:
    // Arbitrary casts to C pointer types count as bitcasts.
    // Otherwise, we should only have block and ObjC pointer casts
    // here if they stay within the type kind.
    if (!getType()->isPointerType()) {
      assert(getType()->isObjCObjectPointerType() ==
             getSubExpr()->getType()->isObjCObjectPointerType());
      assert(getType()->isBlockPointerType() ==
             getSubExpr()->getType()->isBlockPointerType());
    }
    goto CheckNoBasePath;

  case CK_AnyPointerToBlockPointerCast:
    assert(getType()->isBlockPointerType());
    assert(getSubExpr()->getType()->isAnyPointerType() &&
           !getSubExpr()->getType()->isBlockPointerType());
    goto CheckNoBasePath;

  case CK_CopyAndAutoreleaseBlockObject:
    assert(getType()->isBlockPointerType());
    assert(getSubExpr()->getType()->isBlockPointerType());
    goto CheckNoBasePath;

  case CK_FunctionToPointerDecay:
    assert(getType()->isPointerType());
    assert(getSubExpr()->getType()->isFunctionType());
    goto CheckNoBasePath;

  case CK_AddressSpaceConversion: {
    auto Ty = getType();
    auto SETy = getSubExpr()->getType();
    assert(getValueKindForType(Ty) == Expr::getValueKindForType(SETy));
    if (isPRValue() && !Ty->isDependentType() && !SETy->isDependentType()) {
      Ty = Ty->getPointeeType();
      SETy = SETy->getPointeeType();
    }
    assert((Ty->isDependentType() || SETy->isDependentType()) ||
           (!Ty.isNull() && !SETy.isNull() &&
            Ty.getAddressSpace() != SETy.getAddressSpace()));
    goto CheckNoBasePath;
  }
  // These should not have an inheritance path.
  case CK_Dynamic:
  case CK_ToUnion:
  case CK_ArrayToPointerDecay:
  case CK_NullToMemberPointer:
  case CK_NullToPointer:
  case CK_ConstructorConversion:
  case CK_IntegralToPointer:
  case CK_PointerToIntegral:
  case CK_ToVoid:
  case CK_VectorSplat:
  case CK_IntegralCast:
  case CK_BooleanToSignedIntegral:
  case CK_IntegralToFloating:
  case CK_FloatingToIntegral:
  case CK_FloatingCast:
  case CK_ObjCObjectLValueCast:
  case CK_FloatingRealToComplex:
  case CK_FloatingComplexToReal:
  case CK_FloatingComplexCast:
  case CK_FloatingComplexToIntegralComplex:
  case CK_IntegralRealToComplex:
  case CK_IntegralComplexToReal:
  case CK_IntegralComplexCast:
  case CK_IntegralComplexToFloatingComplex:
  case CK_ARCProduceObject:
  case CK_ARCConsumeObject:
  case CK_ARCReclaimReturnedObject:
  case CK_ARCExtendBlockObject:
  case CK_ZeroToOCLOpaqueType:
  case CK_IntToOCLSampler:
  case CK_FloatingToFixedPoint:
  case CK_FixedPointToFloating:
  case CK_FixedPointCast:
  case CK_FixedPointToIntegral:
  case CK_IntegralToFixedPoint:
  case CK_MatrixCast:
  case CK_HLSLVectorTruncation:
    assert(!getType()->isBooleanType() && "unheralded conversion to bool");
    goto CheckNoBasePath;

  case CK_Dependent:
  case CK_LValueToRValue:
  case CK_NoOp:
  case CK_AtomicToNonAtomic:
  case CK_NonAtomicToAtomic:
  case CK_PointerToBoolean:
  case CK_IntegralToBoolean:
  case CK_FloatingToBoolean:
  case CK_MemberPointerToBoolean:
  case CK_FloatingComplexToBoolean:
  case CK_IntegralComplexToBoolean:
  case CK_LValueBitCast:            // -> bool&
  case CK_LValueToRValueBitCast:
  case CK_UserDefinedConversion:    // operator bool()
  case CK_BuiltinFnToFnPtr:
  case CK_FixedPointToBoolean:
  case CK_HLSLArrayRValue:
  CheckNoBasePath:
    assert(path_empty() && "Cast kind should not have a base path!");
    break;
  }
  return true;
}

const char *CastExpr::getCastKindName(CastKind CK) {
  switch (CK) {
#define CAST_OPERATION(Name) case CK_##Name: return #Name;
#include "clang/AST/OperationKinds.def"
  }
  llvm_unreachable("Unhandled cast kind!");
}

namespace {
// Skip over implicit nodes produced as part of semantic analysis.
// Designed for use with IgnoreExprNodes.
static Expr *ignoreImplicitSemaNodes(Expr *E) {
  if (auto *Materialize = dyn_cast<MaterializeTemporaryExpr>(E))
    return Materialize->getSubExpr();

  if (auto *Binder = dyn_cast<CXXBindTemporaryExpr>(E))
    return Binder->getSubExpr();

  if (auto *Full = dyn_cast<FullExpr>(E))
    return Full->getSubExpr();

  if (auto *CPLIE = dyn_cast<CXXParenListInitExpr>(E);
      CPLIE && CPLIE->getInitExprs().size() == 1)
    return CPLIE->getInitExprs()[0];

  return E;
}
} // namespace

Expr *CastExpr::getSubExprAsWritten() {
  const Expr *SubExpr = nullptr;

  for (const CastExpr *E = this; E; E = dyn_cast<ImplicitCastExpr>(SubExpr)) {
    SubExpr = IgnoreExprNodes(E->getSubExpr(), ignoreImplicitSemaNodes);

    // Conversions by constructor and conversion functions have a
    // subexpression describing the call; strip it off.
    if (E->getCastKind() == CK_ConstructorConversion) {
      SubExpr = IgnoreExprNodes(cast<CXXConstructExpr>(SubExpr)->getArg(0),
                                ignoreImplicitSemaNodes);
    } else if (E->getCastKind() == CK_UserDefinedConversion) {
      assert((isa<CXXMemberCallExpr>(SubExpr) || isa<BlockExpr>(SubExpr)) &&
             "Unexpected SubExpr for CK_UserDefinedConversion.");
      if (auto *MCE = dyn_cast<CXXMemberCallExpr>(SubExpr))
        SubExpr = MCE->getImplicitObjectArgument();
    }
  }

  return const_cast<Expr *>(SubExpr);
}

NamedDecl *CastExpr::getConversionFunction() const {
  const Expr *SubExpr = nullptr;

  for (const CastExpr *E = this; E; E = dyn_cast<ImplicitCastExpr>(SubExpr)) {
    SubExpr = IgnoreExprNodes(E->getSubExpr(), ignoreImplicitSemaNodes);

    if (E->getCastKind() == CK_ConstructorConversion)
      return cast<CXXConstructExpr>(SubExpr)->getConstructor();

    if (E->getCastKind() == CK_UserDefinedConversion) {
      if (auto *MCE = dyn_cast<CXXMemberCallExpr>(SubExpr))
        return MCE->getMethodDecl();
    }
  }

  return nullptr;
}

CXXBaseSpecifier **CastExpr::path_buffer() {
  switch (getStmtClass()) {
#define ABSTRACT_STMT(x)
#define CASTEXPR(Type, Base)                                                   \
  case Stmt::Type##Class:                                                      \
    return static_cast<Type *>(this)->getTrailingObjects<CXXBaseSpecifier *>();
#define STMT(Type, Base)
#include "clang/AST/StmtNodes.inc"
  default:
    llvm_unreachable("non-cast expressions not possible here");
  }
}

const FieldDecl *CastExpr::getTargetFieldForToUnionCast(QualType unionType,
                                                        QualType opType) {
  auto RD = unionType->castAs<RecordType>()->getDecl();
  return getTargetFieldForToUnionCast(RD, opType);
}

const FieldDecl *CastExpr::getTargetFieldForToUnionCast(const RecordDecl *RD,
                                                        QualType OpType) {
  auto &Ctx = RD->getASTContext();
  RecordDecl::field_iterator Field, FieldEnd;
  for (Field = RD->field_begin(), FieldEnd = RD->field_end();
       Field != FieldEnd; ++Field) {
    if (Ctx.hasSameUnqualifiedType(Field->getType(), OpType) &&
        !Field->isUnnamedBitField()) {
      return *Field;
    }
  }
  return nullptr;
}

FPOptionsOverride *CastExpr::getTrailingFPFeatures() {
  assert(hasStoredFPFeatures());
  switch (getStmtClass()) {
  case ImplicitCastExprClass:
    return static_cast<ImplicitCastExpr *>(this)
        ->getTrailingObjects<FPOptionsOverride>();
  case CStyleCastExprClass:
    return static_cast<CStyleCastExpr *>(this)
        ->getTrailingObjects<FPOptionsOverride>();
  case CXXFunctionalCastExprClass:
    return static_cast<CXXFunctionalCastExpr *>(this)
        ->getTrailingObjects<FPOptionsOverride>();
  case CXXStaticCastExprClass:
    return static_cast<CXXStaticCastExpr *>(this)
        ->getTrailingObjects<FPOptionsOverride>();
  default:
    llvm_unreachable("Cast does not have FPFeatures");
  }
}

ImplicitCastExpr *ImplicitCastExpr::Create(const ASTContext &C, QualType T,
                                           CastKind Kind, Expr *Operand,
                                           const CXXCastPath *BasePath,
                                           ExprValueKind VK,
                                           FPOptionsOverride FPO) {
  unsigned PathSize = (BasePath ? BasePath->size() : 0);
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *, FPOptionsOverride>(
          PathSize, FPO.requiresTrailingStorage()));
  // Per C++ [conv.lval]p3, lvalue-to-rvalue conversions on class and
  // std::nullptr_t have special semantics not captured by CK_LValueToRValue.
  assert((Kind != CK_LValueToRValue ||
          !(T->isNullPtrType() || T->getAsCXXRecordDecl())) &&
         "invalid type for lvalue-to-rvalue conversion");
  ImplicitCastExpr *E =
      new (Buffer) ImplicitCastExpr(T, Kind, Operand, PathSize, FPO, VK);
  if (PathSize)
    std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                              E->getTrailingObjects<CXXBaseSpecifier *>());
  return E;
}

ImplicitCastExpr *ImplicitCastExpr::CreateEmpty(const ASTContext &C,
                                                unsigned PathSize,
                                                bool HasFPFeatures) {
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *, FPOptionsOverride>(
          PathSize, HasFPFeatures));
  return new (Buffer) ImplicitCastExpr(EmptyShell(), PathSize, HasFPFeatures);
}

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

CStyleCastExpr *CStyleCastExpr::CreateEmpty(const ASTContext &C,
                                            unsigned PathSize,
                                            bool HasFPFeatures) {
  void *Buffer =
      C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *, FPOptionsOverride>(
          PathSize, HasFPFeatures));
  return new (Buffer) CStyleCastExpr(EmptyShell(), PathSize, HasFPFeatures);
}

/// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
/// corresponds to, e.g. "<<=".
StringRef BinaryOperator::getOpcodeStr(Opcode Op) {
  switch (Op) {
#define BINARY_OPERATION(Name, Spelling) case BO_##Name: return Spelling;
#include "clang/AST/OperationKinds.def"
  }
  llvm_unreachable("Invalid OpCode!");
}

BinaryOperatorKind
BinaryOperator::getOverloadedOpcode(OverloadedOperatorKind OO) {
  switch (OO) {
  default: llvm_unreachable("Not an overloadable binary operator");
  case OO_Plus: return BO_Add;
  case OO_Minus: return BO_Sub;
  case OO_Star: return BO_Mul;
  case OO_Slash: return BO_Div;
  case OO_Percent: return BO_Rem;
  case OO_Caret: return BO_Xor;
  case OO_Amp: return BO_And;
  case OO_Pipe: return BO_Or;
  case OO_Equal: return BO_Assign;
  case OO_Spaceship: return BO_Cmp;
  case OO_Less: return BO_LT;
  case OO_Greater: return BO_GT;
  case OO_PlusEqual: return BO_AddAssign;
  case OO_MinusEqual: return BO_SubAssign;
  case OO_StarEqual: return BO_MulAssign;
  case OO_SlashEqual: return BO_DivAssign;
  case OO_PercentEqual: return BO_RemAssign;
  case OO_CaretEqual: return BO_XorAssign;
  case OO_AmpEqual: return BO_AndAssign;
  case OO_PipeEqual: return BO_OrAssign;
  case OO_LessLess: return BO_Shl;
  case OO_GreaterGreater: return BO_Shr;
  case OO_LessLessEqual: return BO_ShlAssign;
  case OO_GreaterGreaterEqual: return BO_ShrAssign;
  case OO_EqualEqual: return BO_EQ;
  case OO_ExclaimEqual: return BO_NE;
  case OO_LessEqual: return BO_LE;
  case OO_GreaterEqual: return BO_GE;
  case OO_AmpAmp: return BO_LAnd;
  case OO_PipePipe: return BO_LOr;
  case OO_Comma: return BO_Comma;
  case OO_ArrowStar: return BO_PtrMemI;
  }
}

OverloadedOperatorKind BinaryOperator::getOverloadedOperator(Opcode Opc) {
  static const OverloadedOperatorKind OverOps[] = {
    /* .* Cannot be overloaded */OO_None, OO_ArrowStar,
    OO_Star, OO_Slash, OO_Percent,
    OO_Plus, OO_Minus,
    OO_LessLess, OO_GreaterGreater,
    OO_Spaceship,
    OO_Less, OO_Greater, OO_LessEqual, OO_GreaterEqual,
    OO_EqualEqual, OO_ExclaimEqual,
    OO_Amp,
    OO_Caret,
    OO_Pipe,
    OO_AmpAmp,
    OO_PipePipe,
    OO_Equal, OO_StarEqual,
    OO_SlashEqual, OO_PercentEqual,
    OO_PlusEqual, OO_MinusEqual,
    OO_LessLessEqual, OO_GreaterGreaterEqual,
    OO_AmpEqual, OO_CaretEqual,
    OO_PipeEqual,
    OO_Comma
  };
  return OverOps[Opc];
}

bool BinaryOperator::isNullPointerArithmeticExtension(ASTContext &Ctx,
                                                      Opcode Opc,
                                                      const Expr *LHS,
                                                      const Expr *RHS) {
  if (Opc != BO_Add)
    return false;

  // Check that we have one pointer and one integer operand.
  const Expr *PExp;
  if (LHS->getType()->isPointerType()) {
    if (!RHS->getType()->isIntegerType())
      return false;
    PExp = LHS;
  } else if (RHS->getType()->isPointerType()) {
    if (!LHS->getType()->isIntegerType())
      return false;
    PExp = RHS;
  } else {
    return false;
  }

  // Check that the pointer is a nullptr.
  if (!PExp->IgnoreParenCasts()
          ->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull))
    return false;

  // Check that the pointee type is char-sized.
  const PointerType *PTy = PExp->getType()->getAs<PointerType>();
  if (!PTy || !PTy->getPointeeType()->isCharType())
    return false;

  return true;
}

SourceLocExpr::SourceLocExpr(const ASTContext &Ctx, SourceLocIdentKind Kind,
                             QualType ResultTy, SourceLocation BLoc,
                             SourceLocation RParenLoc,
                             DeclContext *ParentContext)
    : Expr(SourceLocExprClass, ResultTy, VK_PRValue, OK_Ordinary),
      BuiltinLoc(BLoc), RParenLoc(RParenLoc), ParentContext(ParentContext) {
  SourceLocExprBits.Kind = llvm::to_underlying(Kind);
  // In dependent contexts, function names may change.
  setDependence(MayBeDependent(Kind) && ParentContext->isDependentContext()
                    ? ExprDependence::Value
                    : ExprDependence::None);
}

StringRef SourceLocExpr::getBuiltinStr() const {
  switch (getIdentKind()) {
  case SourceLocIdentKind::File:
    return "__builtin_FILE";
  case SourceLocIdentKind::FileName:
    return "__builtin_FILE_NAME";
  case SourceLocIdentKind::Function:
    return "__builtin_FUNCTION";
  case SourceLocIdentKind::FuncSig:
    return "__builtin_FUNCSIG";
  case SourceLocIdentKind::Line:
    return "__builtin_LINE";
  case SourceLocIdentKind::Column:
    return "__builtin_COLUMN";
  case SourceLocIdentKind::SourceLocStruct:
    return "__builtin_source_location";
  }
  llvm_unreachable("unexpected IdentKind!");
}

APValue SourceLocExpr::EvaluateInContext(const ASTContext &Ctx,
                                         const Expr *DefaultExpr) const {
  SourceLocation Loc;
  const DeclContext *Context;

  if (const auto *DIE = dyn_cast_if_present<CXXDefaultInitExpr>(DefaultExpr)) {
    Loc = DIE->getUsedLocation();
    Context = DIE->getUsedContext();
  } else if (const auto *DAE =
                 dyn_cast_if_present<CXXDefaultArgExpr>(DefaultExpr)) {
    Loc = DAE->getUsedLocation();
    Context = DAE->getUsedContext();
  } else {
    Loc = getLocation();
    Context = getParentContext();
  }

  PresumedLoc PLoc = Ctx.getSourceManager().getPresumedLoc(
      Ctx.getSourceManager().getExpansionRange(Loc).getEnd());

  auto MakeStringLiteral = [&](StringRef Tmp) {
    using LValuePathEntry = APValue::LValuePathEntry;
    StringLiteral *Res = Ctx.getPredefinedStringLiteralFromCache(Tmp);
    // Decay the string to a pointer to the first character.
    LValuePathEntry Path[1] = {LValuePathEntry::ArrayIndex(0)};
    return APValue(Res, CharUnits::Zero(), Path, /*OnePastTheEnd=*/false);
  };

  switch (getIdentKind()) {
  case SourceLocIdentKind::FileName: {
    // __builtin_FILE_NAME() is a Clang-specific extension that expands to the
    // the last part of __builtin_FILE().
    SmallString<256> FileName;
    clang::Preprocessor::processPathToFileName(
        FileName, PLoc, Ctx.getLangOpts(), Ctx.getTargetInfo());
    return MakeStringLiteral(FileName);
  }
  case SourceLocIdentKind::File: {
    SmallString<256> Path(PLoc.getFilename());
    clang::Preprocessor::processPathForFileMacro(Path, Ctx.getLangOpts(),
                                                 Ctx.getTargetInfo());
    return MakeStringLiteral(Path);
  }
  case SourceLocIdentKind::Function:
  case SourceLocIdentKind::FuncSig: {
    const auto *CurDecl = dyn_cast<Decl>(Context);
    const auto Kind = getIdentKind() == SourceLocIdentKind::Function
                          ? PredefinedIdentKind::Function
                          : PredefinedIdentKind::FuncSig;
    return MakeStringLiteral(
        CurDecl ? PredefinedExpr::ComputeName(Kind, CurDecl) : std::string(""));
  }
  case SourceLocIdentKind::Line:
    return APValue(Ctx.MakeIntValue(PLoc.getLine(), Ctx.UnsignedIntTy));
  case SourceLocIdentKind::Column:
    return APValue(Ctx.MakeIntValue(PLoc.getColumn(), Ctx.UnsignedIntTy));
  case SourceLocIdentKind::SourceLocStruct: {
    // Fill in a std::source_location::__impl structure, by creating an
    // artificial file-scoped CompoundLiteralExpr, and returning a pointer to
    // that.
    const CXXRecordDecl *ImplDecl = getType()->getPointeeCXXRecordDecl();
    assert(ImplDecl);

    // Construct an APValue for the __impl struct, and get or create a Decl
    // corresponding to that. Note that we've already verified that the shape of
    // the ImplDecl type is as expected.

    APValue Value(APValue::UninitStruct(), 0, 4);
    for (const FieldDecl *F : ImplDecl->fields()) {
      StringRef Name = F->getName();
      if (Name == "_M_file_name") {
        SmallString<256> Path(PLoc.getFilename());
        clang::Preprocessor::processPathForFileMacro(Path, Ctx.getLangOpts(),
                                                     Ctx.getTargetInfo());
        Value.getStructField(F->getFieldIndex()) = MakeStringLiteral(Path);
      } else if (Name == "_M_function_name") {
        // Note: this emits the PrettyFunction name -- different than what
        // __builtin_FUNCTION() above returns!
        const auto *CurDecl = dyn_cast<Decl>(Context);
        Value.getStructField(F->getFieldIndex()) = MakeStringLiteral(
            CurDecl && !isa<TranslationUnitDecl>(CurDecl)
                ? StringRef(PredefinedExpr::ComputeName(
                      PredefinedIdentKind::PrettyFunction, CurDecl))
                : "");
      } else if (Name == "_M_line") {
        llvm::APSInt IntVal = Ctx.MakeIntValue(PLoc.getLine(), F->getType());
        Value.getStructField(F->getFieldIndex()) = APValue(IntVal);
      } else if (Name == "_M_column") {
        llvm::APSInt IntVal = Ctx.MakeIntValue(PLoc.getColumn(), F->getType());
        Value.getStructField(F->getFieldIndex()) = APValue(IntVal);
      }
    }

    UnnamedGlobalConstantDecl *GV =
        Ctx.getUnnamedGlobalConstantDecl(getType()->getPointeeType(), Value);

    return APValue(GV, CharUnits::Zero(), ArrayRef<APValue::LValuePathEntry>{},
                   false);
  }
  }
  llvm_unreachable("unhandled case");
}

EmbedExpr::EmbedExpr(const ASTContext &Ctx, SourceLocation Loc,
                     EmbedDataStorage *Data, unsigned Begin,
                     unsigned NumOfElements)
    : Expr(EmbedExprClass, Ctx.IntTy, VK_PRValue, OK_Ordinary),
      EmbedKeywordLoc(Loc), Ctx(&Ctx), Data(Data), Begin(Begin),
      NumOfElements(NumOfElements) {
  setDependence(ExprDependence::None);
  FakeChildNode = IntegerLiteral::Create(
      Ctx, llvm::APInt::getZero(Ctx.getTypeSize(getType())), getType(), Loc);
}

InitListExpr::InitListExpr(const ASTContext &C, SourceLocation lbraceloc,
                           ArrayRef<Expr *> initExprs, SourceLocation rbraceloc)
    : Expr(InitListExprClass, QualType(), VK_PRValue, OK_Ordinary),
      InitExprs(C, initExprs.size()), LBraceLoc(lbraceloc),
      RBraceLoc(rbraceloc), AltForm(nullptr, true) {
  sawArrayRangeDesignator(false);
  InitExprs.insert(C, InitExprs.end(), initExprs.begin(), initExprs.end());

  setDependence(computeDependence(this));
}

void InitListExpr::reserveInits(const ASTContext &C, unsigned NumInits) {
  if (NumInits > InitExprs.size())
    InitExprs.reserve(C, NumInits);
}

void InitListExpr::resizeInits(const ASTContext &C, unsigned NumInits) {
  InitExprs.resize(C, NumInits, nullptr);
}

Expr *InitListExpr::updateInit(const ASTContext &C, unsigned Init, Expr *expr) {
  if (Init >= InitExprs.size()) {
    InitExprs.insert(C, InitExprs.end(), Init - InitExprs.size() + 1, nullptr);
    setInit(Init, expr);
    return nullptr;
  }

  Expr *Result = cast_or_null<Expr>(InitExprs[Init]);
  setInit(Init, expr);
  return Result;
}

void InitListExpr::setArrayFiller(Expr *filler) {
  assert(!hasArrayFiller() && "Filler already set!");
  ArrayFillerOrUnionFieldInit = filler;
  // Fill out any "holes" in the array due to designated initializers.
  Expr **inits = getInits();
  for (unsigned i = 0, e = getNumInits(); i != e; ++i)
    if (inits[i] == nullptr)
      inits[i] = filler;
}

bool InitListExpr::isStringLiteralInit() const {
  if (getNumInits() != 1)
    return false;
  const ArrayType *AT = getType()->getAsArrayTypeUnsafe();
  if (!AT || !AT->getElementType()->isIntegerType())
    return false;
  // It is possible for getInit() to return null.
  const Expr *Init = getInit(0);
  if (!Init)
    return false;
  Init = Init->IgnoreParenImpCasts();
  return isa<StringLiteral>(Init) || isa<ObjCEncodeExpr>(Init);
}

bool InitListExpr::isTransparent() const {
  assert(isSemanticForm() && "syntactic form never semantically transparent");

  // A glvalue InitListExpr is always just sugar.
  if (isGLValue()) {
    assert(getNumInits() == 1 && "multiple inits in glvalue init list");
    return true;
  }

  // Otherwise, we're sugar if and only if we have exactly one initializer that
  // is of the same type.
  if (getNumInits() != 1 || !getInit(0))
    return false;

  // Don't confuse aggregate initialization of a struct X { X &x; }; with a
  // transparent struct copy.
  if (!getInit(0)->isPRValue() && getType()->isRecordType())
    return false;

  return getType().getCanonicalType() ==
         getInit(0)->getType().getCanonicalType();
}

bool InitListExpr::isIdiomaticZeroInitializer(const LangOptions &LangOpts) const {
  assert(isSyntacticForm() && "only test syntactic form as zero initializer");

  if (LangOpts.CPlusPlus || getNumInits() != 1 || !getInit(0)) {
    return false;
  }

  const IntegerLiteral *Lit = dyn_cast<IntegerLiteral>(getInit(0)->IgnoreImplicit());
  return Lit && Lit->getValue() == 0;
}

SourceLocation InitListExpr::getBeginLoc() const {
  if (InitListExpr *SyntacticForm = getSyntacticForm())
    return SyntacticForm->getBeginLoc();
  SourceLocation Beg = LBraceLoc;
  if (Beg.isInvalid()) {
    // Find the first non-null initializer.
    for (InitExprsTy::const_iterator I = InitExprs.begin(),
                                     E = InitExprs.end();
      I != E; ++I) {
      if (Stmt *S = *I) {
        Beg = S->getBeginLoc();
        break;
      }
    }
  }
  return Beg;
}

SourceLocation InitListExpr::getEndLoc() const {
  if (InitListExpr *SyntacticForm = getSyntacticForm())
    return SyntacticForm->getEndLoc();
  SourceLocation End = RBraceLoc;
  if (End.isInvalid()) {
    // Find the first non-null initializer from the end.
    for (Stmt *S : llvm::reverse(InitExprs)) {
      if (S) {
        End = S->getEndLoc();
        break;
      }
    }
  }
  return End;
}

/// getFunctionType - Return the underlying function type for this block.
///
const FunctionProtoType *BlockExpr::getFunctionType() const {
  // The block pointer is never sugared, but the function type might be.
  return cast<BlockPointerType>(getType())
           ->getPointeeType()->castAs<FunctionProtoType>();
}

SourceLocation BlockExpr::getCaretLocation() const {
  return TheBlock->getCaretLocation();
}
const Stmt *BlockExpr::getBody() const {
  return TheBlock->getBody();
}
Stmt *BlockExpr::getBody() {
  return TheBlock->getBody();
}


//===----------------------------------------------------------------------===//
// Generic Expression Routines
//===----------------------------------------------------------------------===//

bool Expr::isReadIfDiscardedInCPlusPlus11() const {
  // In C++11, discarded-value expressions of a certain form are special,
  // according to [expr]p10:
  //   The lvalue-to-rvalue conversion (4.1) is applied only if the
  //   expression is a glvalue of volatile-qualified type and it has
  //   one of the following forms:
  if (!isGLValue() || !getType().isVolatileQualified())
    return false;

  const Expr *E = IgnoreParens();

  //   - id-expression (5.1.1),
  if (isa<DeclRefExpr>(E))
    return true;

  //   - subscripting (5.2.1),
  if (isa<ArraySubscriptExpr>(E))
    return true;

  //   - class member access (5.2.5),
  if (isa<MemberExpr>(E))
    return true;

  //   - indirection (5.3.1),
  if (auto *UO = dyn_cast<UnaryOperator>(E))
    if (UO->getOpcode() == UO_Deref)
      return true;

  if (auto *BO = dyn_cast<BinaryOperator>(E)) {
    //   - pointer-to-member operation (5.5),
    if (BO->isPtrMemOp())
      return true;

    //   - comma expression (5.18) where the right operand is one of the above.
    if (BO->getOpcode() == BO_Comma)
      return BO->getRHS()->isReadIfDiscardedInCPlusPlus11();
  }

  //   - conditional expression (5.16) where both the second and the third
  //     operands are one of the above, or
  if (auto *CO = dyn_cast<ConditionalOperator>(E))
    return CO->getTrueExpr()->isReadIfDiscardedInCPlusPlus11() &&
           CO->getFalseExpr()->isReadIfDiscardedInCPlusPlus11();
  // The related edge case of "*x ?: *x".
  if (auto *BCO =
          dyn_cast<BinaryConditionalOperator>(E)) {
    if (auto *OVE = dyn_cast<OpaqueValueExpr>(BCO->getTrueExpr()))
      return OVE->getSourceExpr()->isReadIfDiscardedInCPlusPlus11() &&
             BCO->getFalseExpr()->isReadIfDiscardedInCPlusPlus11();
  }

  // Objective-C++ extensions to the rule.
  if (isa<ObjCIvarRefExpr>(E))
    return true;
  if (const auto *POE = dyn_cast<PseudoObjectExpr>(E)) {
    if (isa<ObjCPropertyRefExpr, ObjCSubscriptRefExpr>(POE->getSyntacticForm()))
      return true;
  }

  return false;
}

/// isUnusedResultAWarning - Return true if this immediate expression should
/// be warned about if the result is unused.  If so, fill in Loc and Ranges
/// with location to warn on and the source range[s] to report with the
/// warning.
bool Expr::isUnusedResultAWarning(const Expr *&WarnE, SourceLocation &Loc,
                                  SourceRange &R1, SourceRange &R2,
                                  ASTContext &Ctx) const {
  // Don't warn if the expr is type dependent. The type could end up
  // instantiating to void.
  if (isTypeDependent())
    return false;

  switch (getStmtClass()) {
  default:
    if (getType()->isVoidType())
      return false;
    WarnE = this;
    Loc = getExprLoc();
    R1 = getSourceRange();
    return true;
  case ParenExprClass:
    return cast<ParenExpr>(this)->getSubExpr()->
      isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  case GenericSelectionExprClass:
    return cast<GenericSelectionExpr>(this)->getResultExpr()->
      isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  case CoawaitExprClass:
  case CoyieldExprClass:
    return cast<CoroutineSuspendExpr>(this)->getResumeExpr()->
      isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  case ChooseExprClass:
    return cast<ChooseExpr>(this)->getChosenSubExpr()->
      isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  case UnaryOperatorClass: {
    const UnaryOperator *UO = cast<UnaryOperator>(this);

    switch (UO->getOpcode()) {
    case UO_Plus:
    case UO_Minus:
    case UO_AddrOf:
    case UO_Not:
    case UO_LNot:
    case UO_Deref:
      break;
    case UO_Coawait:
      // This is just the 'operator co_await' call inside the guts of a
      // dependent co_await call.
    case UO_PostInc:
    case UO_PostDec:
    case UO_PreInc:
    case UO_PreDec:                 // ++/--
      return false;  // Not a warning.
    case UO_Real:
    case UO_Imag:
      // accessing a piece of a volatile complex is a side-effect.
      if (Ctx.getCanonicalType(UO->getSubExpr()->getType())
          .isVolatileQualified())
        return false;
      break;
    case UO_Extension:
      return UO->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    }
    WarnE = this;
    Loc = UO->getOperatorLoc();
    R1 = UO->getSubExpr()->getSourceRange();
    return true;
  }
  case BinaryOperatorClass: {
    const BinaryOperator *BO = cast<BinaryOperator>(this);
    switch (BO->getOpcode()) {
      default:
        break;
      // Consider the RHS of comma for side effects. LHS was checked by
      // Sema::CheckCommaOperands.
      case BO_Comma:
        // ((foo = <blah>), 0) is an idiom for hiding the result (and
        // lvalue-ness) of an assignment written in a macro.
        if (IntegerLiteral *IE =
              dyn_cast<IntegerLiteral>(BO->getRHS()->IgnoreParens()))
          if (IE->getValue() == 0)
            return false;
        return BO->getRHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
      // Consider '||', '&&' to have side effects if the LHS or RHS does.
      case BO_LAnd:
      case BO_LOr:
        if (!BO->getLHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx) ||
            !BO->getRHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx))
          return false;
        break;
    }
    if (BO->isAssignmentOp())
      return false;
    WarnE = this;
    Loc = BO->getOperatorLoc();
    R1 = BO->getLHS()->getSourceRange();
    R2 = BO->getRHS()->getSourceRange();
    return true;
  }
  case CompoundAssignOperatorClass:
  case VAArgExprClass:
  case AtomicExprClass:
    return false;

  case ConditionalOperatorClass: {
    // If only one of the LHS or RHS is a warning, the operator might
    // be being used for control flow. Only warn if both the LHS and
    // RHS are warnings.
    const auto *Exp = cast<ConditionalOperator>(this);
    return Exp->getLHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx) &&
           Exp->getRHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  }
  case BinaryConditionalOperatorClass: {
    const auto *Exp = cast<BinaryConditionalOperator>(this);
    return Exp->getFalseExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  }

  case MemberExprClass:
    WarnE = this;
    Loc = cast<MemberExpr>(this)->getMemberLoc();
    R1 = SourceRange(Loc, Loc);
    R2 = cast<MemberExpr>(this)->getBase()->getSourceRange();
    return true;

  case ArraySubscriptExprClass:
    WarnE = this;
    Loc = cast<ArraySubscriptExpr>(this)->getRBracketLoc();
    R1 = cast<ArraySubscriptExpr>(this)->getLHS()->getSourceRange();
    R2 = cast<ArraySubscriptExpr>(this)->getRHS()->getSourceRange();
    return true;

  case CXXOperatorCallExprClass: {
    // Warn about operator ==,!=,<,>,<=, and >= even when user-defined operator
    // overloads as there is no reasonable way to define these such that they
    // have non-trivial, desirable side-effects. See the -Wunused-comparison
    // warning: operators == and != are commonly typo'ed, and so warning on them
    // provides additional value as well. If this list is updated,
    // DiagnoseUnusedComparison should be as well.
    const CXXOperatorCallExpr *Op = cast<CXXOperatorCallExpr>(this);
    switch (Op->getOperator()) {
    default:
      break;
    case OO_EqualEqual:
    case OO_ExclaimEqual:
    case OO_Less:
    case OO_Greater:
    case OO_GreaterEqual:
    case OO_LessEqual:
      if (Op->getCallReturnType(Ctx)->isReferenceType() ||
          Op->getCallReturnType(Ctx)->isVoidType())
        break;
      WarnE = this;
      Loc = Op->getOperatorLoc();
      R1 = Op->getSourceRange();
      return true;
    }

    // Fallthrough for generic call handling.
    [[fallthrough]];
  }
  case CallExprClass:
  case CXXMemberCallExprClass:
  case UserDefinedLiteralClass: {
    // If this is a direct call, get the callee.
    const CallExpr *CE = cast<CallExpr>(this);
    if (const Decl *FD = CE->getCalleeDecl()) {
      // If the callee has attribute pure, const, or warn_unused_result, warn
      // about it. void foo() { strlen("bar"); } should warn.
      //
      // Note: If new cases are added here, DiagnoseUnusedExprResult should be
      // updated to match for QoI.
      if (CE->hasUnusedResultAttr(Ctx) ||
          FD->hasAttr<PureAttr>() || FD->hasAttr<ConstAttr>()) {
        WarnE = this;
        Loc = CE->getCallee()->getBeginLoc();
        R1 = CE->getCallee()->getSourceRange();

        if (unsigned NumArgs = CE->getNumArgs())
          R2 = SourceRange(CE->getArg(0)->getBeginLoc(),
                           CE->getArg(NumArgs - 1)->getEndLoc());
        return true;
      }
    }
    return false;
  }

  // If we don't know precisely what we're looking at, let's not warn.
  case UnresolvedLookupExprClass:
  case CXXUnresolvedConstructExprClass:
  case RecoveryExprClass:
    return false;

  case CXXTemporaryObjectExprClass:
  case CXXConstructExprClass: {
    if (const CXXRecordDecl *Type = getType()->getAsCXXRecordDecl()) {
      const auto *WarnURAttr = Type->getAttr<WarnUnusedResultAttr>();
      if (Type->hasAttr<WarnUnusedAttr>() ||
          (WarnURAttr && WarnURAttr->IsCXX11NoDiscard())) {
        WarnE = this;
        Loc = getBeginLoc();
        R1 = getSourceRange();
        return true;
      }
    }

    const auto *CE = cast<CXXConstructExpr>(this);
    if (const CXXConstructorDecl *Ctor = CE->getConstructor()) {
      const auto *WarnURAttr = Ctor->getAttr<WarnUnusedResultAttr>();
      if (WarnURAttr && WarnURAttr->IsCXX11NoDiscard()) {
        WarnE = this;
        Loc = getBeginLoc();
        R1 = getSourceRange();

        if (unsigned NumArgs = CE->getNumArgs())
          R2 = SourceRange(CE->getArg(0)->getBeginLoc(),
                           CE->getArg(NumArgs - 1)->getEndLoc());
        return true;
      }
    }

    return false;
  }

  case ObjCMessageExprClass: {
    const ObjCMessageExpr *ME = cast<ObjCMessageExpr>(this);
    if (Ctx.getLangOpts().ObjCAutoRefCount &&
        ME->isInstanceMessage() &&
        !ME->getType()->isVoidType() &&
        ME->getMethodFamily() == OMF_init) {
      WarnE = this;
      Loc = getExprLoc();
      R1 = ME->getSourceRange();
      return true;
    }

    if (const ObjCMethodDecl *MD = ME->getMethodDecl())
      if (MD->hasAttr<WarnUnusedResultAttr>()) {
        WarnE = this;
        Loc = getExprLoc();
        return true;
      }

    return false;
  }

  case ObjCPropertyRefExprClass:
  case ObjCSubscriptRefExprClass:
    WarnE = this;
    Loc = getExprLoc();
    R1 = getSourceRange();
    return true;

  case PseudoObjectExprClass: {
    const auto *POE = cast<PseudoObjectExpr>(this);

    // For some syntactic forms, we should always warn.
    if (isa<ObjCPropertyRefExpr, ObjCSubscriptRefExpr>(
            POE->getSyntacticForm())) {
      WarnE = this;
      Loc = getExprLoc();
      R1 = getSourceRange();
      return true;
    }

    // For others, we should never warn.
    if (auto *BO = dyn_cast<BinaryOperator>(POE->getSyntacticForm()))
      if (BO->isAssignmentOp())
        return false;
    if (auto *UO = dyn_cast<UnaryOperator>(POE->getSyntacticForm()))
      if (UO->isIncrementDecrementOp())
        return false;

    // Otherwise, warn if the result expression would warn.
    const Expr *Result = POE->getResultExpr();
    return Result && Result->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  }

  case StmtExprClass: {
    // Statement exprs don't logically have side effects themselves, but are
    // sometimes used in macros in ways that give them a type that is unused.
    // For example ({ blah; foo(); }) will end up with a type if foo has a type.
    // however, if the result of the stmt expr is dead, we don't want to emit a
    // warning.
    const CompoundStmt *CS = cast<StmtExpr>(this)->getSubStmt();
    if (!CS->body_empty()) {
      if (const Expr *E = dyn_cast<Expr>(CS->body_back()))
        return E->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
      if (const LabelStmt *Label = dyn_cast<LabelStmt>(CS->body_back()))
        if (const Expr *E = dyn_cast<Expr>(Label->getSubStmt()))
          return E->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    }

    if (getType()->isVoidType())
      return false;
    WarnE = this;
    Loc = cast<StmtExpr>(this)->getLParenLoc();
    R1 = getSourceRange();
    return true;
  }
  case CXXFunctionalCastExprClass:
  case CStyleCastExprClass: {
    // Ignore an explicit cast to void, except in C++98 if the operand is a
    // volatile glvalue for which we would trigger an implicit read in any
    // other language mode. (Such an implicit read always happens as part of
    // the lvalue conversion in C, and happens in C++ for expressions of all
    // forms where it seems likely the user intended to trigger a volatile
    // load.)
    const CastExpr *CE = cast<CastExpr>(this);
    const Expr *SubE = CE->getSubExpr()->IgnoreParens();
    if (CE->getCastKind() == CK_ToVoid) {
      if (Ctx.getLangOpts().CPlusPlus && !Ctx.getLangOpts().CPlusPlus11 &&
          SubE->isReadIfDiscardedInCPlusPlus11()) {
        // Suppress the "unused value" warning for idiomatic usage of
        // '(void)var;' used to suppress "unused variable" warnings.
        if (auto *DRE = dyn_cast<DeclRefExpr>(SubE))
          if (auto *VD = dyn_cast<VarDecl>(DRE->getDecl()))
            if (!VD->isExternallyVisible())
              return false;

        // The lvalue-to-rvalue conversion would have no effect for an array.
        // It's implausible that the programmer expected this to result in a
        // volatile array load, so don't warn.
        if (SubE->getType()->isArrayType())
          return false;

        return SubE->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
      }
      return false;
    }

    // If this is a cast to a constructor conversion, check the operand.
    // Otherwise, the result of the cast is unused.
    if (CE->getCastKind() == CK_ConstructorConversion)
      return CE->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    if (CE->getCastKind() == CK_Dependent)
      return false;

    WarnE = this;
    if (const CXXFunctionalCastExpr *CXXCE =
            dyn_cast<CXXFunctionalCastExpr>(this)) {
      Loc = CXXCE->getBeginLoc();
      R1 = CXXCE->getSubExpr()->getSourceRange();
    } else {
      const CStyleCastExpr *CStyleCE = cast<CStyleCastExpr>(this);
      Loc = CStyleCE->getLParenLoc();
      R1 = CStyleCE->getSubExpr()->getSourceRange();
    }
    return true;
  }
  case ImplicitCastExprClass: {
    const CastExpr *ICE = cast<ImplicitCastExpr>(this);

    // lvalue-to-rvalue conversion on a volatile lvalue is a side-effect.
    if (ICE->getCastKind() == CK_LValueToRValue &&
        ICE->getSubExpr()->getType().isVolatileQualified())
      return false;

    return ICE->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  }
  case CXXDefaultArgExprClass:
    return (cast<CXXDefaultArgExpr>(this)
            ->getExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx));
  case CXXDefaultInitExprClass:
    return (cast<CXXDefaultInitExpr>(this)
            ->getExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx));

  case CXXNewExprClass:
    // FIXME: In theory, there might be new expressions that don't have side
    // effects (e.g. a placement new with an uninitialized POD).
  case CXXDeleteExprClass:
    return false;
  case MaterializeTemporaryExprClass:
    return cast<MaterializeTemporaryExpr>(this)
        ->getSubExpr()
        ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  case CXXBindTemporaryExprClass:
    return cast<CXXBindTemporaryExpr>(this)->getSubExpr()
               ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  case ExprWithCleanupsClass:
    return cast<ExprWithCleanups>(this)->getSubExpr()
               ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  }
}

/// isOBJCGCCandidate - Check if an expression is objc gc'able.
/// returns true, if it is; false otherwise.
bool Expr::isOBJCGCCandidate(ASTContext &Ctx) const {
  const Expr *E = IgnoreParens();
  switch (E->getStmtClass()) {
  default:
    return false;
  case ObjCIvarRefExprClass:
    return true;
  case Expr::UnaryOperatorClass:
    return cast<UnaryOperator>(E)->getSubExpr()->isOBJCGCCandidate(Ctx);
  case ImplicitCastExprClass:
    return cast<ImplicitCastExpr>(E)->getSubExpr()->isOBJCGCCandidate(Ctx);
  case MaterializeTemporaryExprClass:
    return cast<MaterializeTemporaryExpr>(E)->getSubExpr()->isOBJCGCCandidate(
        Ctx);
  case CStyleCastExprClass:
    return cast<CStyleCastExpr>(E)->getSubExpr()->isOBJCGCCandidate(Ctx);
  case DeclRefExprClass: {
    const Decl *D = cast<DeclRefExpr>(E)->getDecl();

    if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
      if (VD->hasGlobalStorage())
        return true;
      QualType T = VD->getType();
      // dereferencing to a  pointer is always a gc'able candidate,
      // unless it is __weak.
      return T->isPointerType() &&
             (Ctx.getObjCGCAttrKind(T) != Qualifiers::Weak);
    }
    return false;
  }
  case MemberExprClass: {
    const MemberExpr *M = cast<MemberExpr>(E);
    return M->getBase()->isOBJCGCCandidate(Ctx);
  }
  case ArraySubscriptExprClass:
    return cast<ArraySubscriptExpr>(E)->getBase()->isOBJCGCCandidate(Ctx);
  }
}

bool Expr::isBoundMemberFunction(ASTContext &Ctx) const {
  if (isTypeDependent())
    return false;
  return ClassifyLValue(Ctx) == Expr::LV_MemberFunction;
}

QualType Expr::findBoundMemberType(const Expr *expr) {
  assert(expr->hasPlaceholderType(BuiltinType::BoundMember));

  // Bound member expressions are always one of these possibilities:
  //   x->m      x.m      x->*y      x.*y
  // (possibly parenthesized)

  expr = expr->IgnoreParens();
  if (const MemberExpr *mem = dyn_cast<MemberExpr>(expr)) {
    assert(isa<CXXMethodDecl>(mem->getMemberDecl()));
    return mem->getMemberDecl()->getType();
  }

  if (const BinaryOperator *op = dyn_cast<BinaryOperator>(expr)) {
    QualType type = op->getRHS()->getType()->castAs<MemberPointerType>()
                      ->getPointeeType();
    assert(type->isFunctionType());
    return type;
  }

  assert(isa<UnresolvedMemberExpr>(expr) || isa<CXXPseudoDestructorExpr>(expr));
  return QualType();
}

Expr *Expr::IgnoreImpCasts() {
  return IgnoreExprNodes(this, IgnoreImplicitCastsSingleStep);
}

Expr *Expr::IgnoreCasts() {
  return IgnoreExprNodes(this, IgnoreCastsSingleStep);
}

Expr *Expr::IgnoreImplicit() {
  return IgnoreExprNodes(this, IgnoreImplicitSingleStep);
}

Expr *Expr::IgnoreImplicitAsWritten() {
  return IgnoreExprNodes(this, IgnoreImplicitAsWrittenSingleStep);
}

Expr *Expr::IgnoreParens() {
  return IgnoreExprNodes(this, IgnoreParensSingleStep);
}

Expr *Expr::IgnoreParenImpCasts() {
  return IgnoreExprNodes(this, IgnoreParensSingleStep,
                         IgnoreImplicitCastsExtraSingleStep);
}

Expr *Expr::IgnoreParenCasts() {
  return IgnoreExprNodes(this, IgnoreParensSingleStep, IgnoreCastsSingleStep);
}

Expr *Expr::IgnoreConversionOperatorSingleStep() {
  if (auto *MCE = dyn_cast<CXXMemberCallExpr>(this)) {
    if (isa_and_nonnull<CXXConversionDecl>(MCE->getMethodDecl()))
      return MCE->getImplicitObjectArgument();
  }
  return this;
}

Expr *Expr::IgnoreParenLValueCasts() {
  return IgnoreExprNodes(this, IgnoreParensSingleStep,
                         IgnoreLValueCastsSingleStep);
}

Expr *Expr::IgnoreParenBaseCasts() {
  return IgnoreExprNodes(this, IgnoreParensSingleStep,
                         IgnoreBaseCastsSingleStep);
}

Expr *Expr::IgnoreParenNoopCasts(const ASTContext &Ctx) {
  auto IgnoreNoopCastsSingleStep = [&Ctx](Expr *E) {
    if (auto *CE = dyn_cast<CastExpr>(E)) {
      // We ignore integer <-> casts that are of the same width, ptr<->ptr and
      // ptr<->int casts of the same width. We also ignore all identity casts.
      Expr *SubExpr = CE->getSubExpr();
      bool IsIdentityCast =
          Ctx.hasSameUnqualifiedType(E->getType(), SubExpr->getType());
      bool IsSameWidthCast = (E->getType()->isPointerType() ||
                              E->getType()->isIntegralType(Ctx)) &&
                             (SubExpr->getType()->isPointerType() ||
                              SubExpr->getType()->isIntegralType(Ctx)) &&
                             (Ctx.getTypeSize(E->getType()) ==
                              Ctx.getTypeSize(SubExpr->getType()));

      if (IsIdentityCast || IsSameWidthCast)
        return SubExpr;
    } else if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
      return NTTP->getReplacement();

    return E;
  };
  return IgnoreExprNodes(this, IgnoreParensSingleStep,
                         IgnoreNoopCastsSingleStep);
}

Expr *Expr::IgnoreUnlessSpelledInSource() {
  auto IgnoreImplicitConstructorSingleStep = [](Expr *E) {
    if (auto *Cast = dyn_cast<CXXFunctionalCastExpr>(E)) {
      auto *SE = Cast->getSubExpr();
      if (SE->getSourceRange() == E->getSourceRange())
        return SE;
    }

    if (auto *C = dyn_cast<CXXConstructExpr>(E)) {
      auto NumArgs = C->getNumArgs();
      if (NumArgs == 1 ||
          (NumArgs > 1 && isa<CXXDefaultArgExpr>(C->getArg(1)))) {
        Expr *A = C->getArg(0);
        if (A->getSourceRange() == E->getSourceRange() || C->isElidable())
          return A;
      }
    }
    return E;
  };
  auto IgnoreImplicitMemberCallSingleStep = [](Expr *E) {
    if (auto *C = dyn_cast<CXXMemberCallExpr>(E)) {
      Expr *ExprNode = C->getImplicitObjectArgument();
      if (ExprNode->getSourceRange() == E->getSourceRange()) {
        return ExprNode;
      }
      if (auto *PE = dyn_cast<ParenExpr>(ExprNode)) {
        if (PE->getSourceRange() == C->getSourceRange()) {
          return cast<Expr>(PE);
        }
      }
      ExprNode = ExprNode->IgnoreParenImpCasts();
      if (ExprNode->getSourceRange() == E->getSourceRange())
        return ExprNode;
    }
    return E;
  };
  return IgnoreExprNodes(
      this, IgnoreImplicitSingleStep, IgnoreImplicitCastsExtraSingleStep,
      IgnoreParensOnlySingleStep, IgnoreImplicitConstructorSingleStep,
      IgnoreImplicitMemberCallSingleStep);
}

bool Expr::isDefaultArgument() const {
  const Expr *E = this;
  if (const MaterializeTemporaryExpr *M = dyn_cast<MaterializeTemporaryExpr>(E))
    E = M->getSubExpr();

  while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
    E = ICE->getSubExprAsWritten();

  return isa<CXXDefaultArgExpr>(E);
}

/// Skip over any no-op casts and any temporary-binding
/// expressions.
static const Expr *skipTemporaryBindingsNoOpCastsAndParens(const Expr *E) {
  if (const MaterializeTemporaryExpr *M = dyn_cast<MaterializeTemporaryExpr>(E))
    E = M->getSubExpr();

  while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
    if (ICE->getCastKind() == CK_NoOp)
      E = ICE->getSubExpr();
    else
      break;
  }

  while (const CXXBindTemporaryExpr *BE = dyn_cast<CXXBindTemporaryExpr>(E))
    E = BE->getSubExpr();

  while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
    if (ICE->getCastKind() == CK_NoOp)
      E = ICE->getSubExpr();
    else
      break;
  }

  return E->IgnoreParens();
}

/// isTemporaryObject - Determines if this expression produces a
/// temporary of the given class type.
bool Expr::isTemporaryObject(ASTContext &C, const CXXRecordDecl *TempTy) const {
  if (!C.hasSameUnqualifiedType(getType(), C.getTypeDeclType(TempTy)))
    return false;

  const Expr *E = skipTemporaryBindingsNoOpCastsAndParens(this);

  // Temporaries are by definition pr-values of class type.
  if (!E->Classify(C).isPRValue()) {
    // In this context, property reference is a message call and is pr-value.
    if (!isa<ObjCPropertyRefExpr>(E))
      return false;
  }

  // Black-list a few cases which yield pr-values of class type that don't
  // refer to temporaries of that type:

  // - implicit derived-to-base conversions
  if (isa<ImplicitCastExpr>(E)) {
    switch (cast<ImplicitCastExpr>(E)->getCastKind()) {
    case CK_DerivedToBase:
    case CK_UncheckedDerivedToBase:
      return false;
    default:
      break;
    }
  }

  // - member expressions (all)
  if (isa<MemberExpr>(E))
    return false;

  if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E))
    if (BO->isPtrMemOp())
      return false;

  // - opaque values (all)
  if (isa<OpaqueValueExpr>(E))
    return false;

  return true;
}

bool Expr::isImplicitCXXThis() const {
  const Expr *E = this;

  // Strip away parentheses and casts we don't care about.
  while (true) {
    if (const ParenExpr *Paren = dyn_cast<ParenExpr>(E)) {
      E = Paren->getSubExpr();
      continue;
    }

    if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
      if (ICE->getCastKind() == CK_NoOp ||
          ICE->getCastKind() == CK_LValueToRValue ||
          ICE->getCastKind() == CK_DerivedToBase ||
          ICE->getCastKind() == CK_UncheckedDerivedToBase) {
        E = ICE->getSubExpr();
        continue;
      }
    }

    if (const UnaryOperator* UnOp = dyn_cast<UnaryOperator>(E)) {
      if (UnOp->getOpcode() == UO_Extension) {
        E = UnOp->getSubExpr();
        continue;
      }
    }

    if (const MaterializeTemporaryExpr *M
                                      = dyn_cast<MaterializeTemporaryExpr>(E)) {
      E = M->getSubExpr();
      continue;
    }

    break;
  }

  if (const CXXThisExpr *This = dyn_cast<CXXThisExpr>(E))
    return This->isImplicit();

  return false;
}

/// hasAnyTypeDependentArguments - Determines if any of the expressions
/// in Exprs is type-dependent.
bool Expr::hasAnyTypeDependentArguments(ArrayRef<Expr *> Exprs) {
  for (unsigned I = 0; I < Exprs.size(); ++I)
    if (Exprs[I]->isTypeDependent())
      return true;

  return false;
}

bool Expr::isConstantInitializer(ASTContext &Ctx, bool IsForRef,
                                 const Expr **Culprit) const {
  assert(!isValueDependent() &&
         "Expression evaluator can't be called on a dependent expression.");

  // This function is attempting whether an expression is an initializer
  // which can be evaluated at compile-time. It very closely parallels
  // ConstExprEmitter in CGExprConstant.cpp; if they don't match, it
  // will lead to unexpected results.  Like ConstExprEmitter, it falls back
  // to isEvaluatable most of the time.
  //
  // If we ever capture reference-binding directly in the AST, we can
  // kill the second parameter.

  if (IsForRef) {
    if (auto *EWC = dyn_cast<ExprWithCleanups>(this))
      return EWC->getSubExpr()->isConstantInitializer(Ctx, true, Culprit);
    if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(this))
      return MTE->getSubExpr()->isConstantInitializer(Ctx, false, Culprit);
    EvalResult Result;
    if (EvaluateAsLValue(Result, Ctx) && !Result.HasSideEffects)
      return true;
    if (Culprit)
      *Culprit = this;
    return false;
  }

  switch (getStmtClass()) {
  default: break;
  case Stmt::ExprWithCleanupsClass:
    return cast<ExprWithCleanups>(this)->getSubExpr()->isConstantInitializer(
        Ctx, IsForRef, Culprit);
  case StringLiteralClass:
  case ObjCEncodeExprClass:
    return true;
  case CXXTemporaryObjectExprClass:
  case CXXConstructExprClass: {
    const CXXConstructExpr *CE = cast<CXXConstructExpr>(this);

    if (CE->getConstructor()->isTrivial() &&
        CE->getConstructor()->getParent()->hasTrivialDestructor()) {
      // Trivial default constructor
      if (!CE->getNumArgs()) return true;

      // Trivial copy constructor
      assert(CE->getNumArgs() == 1 && "trivial ctor with > 1 argument");
      return CE->getArg(0)->isConstantInitializer(Ctx, false, Culprit);
    }

    break;
  }
  case ConstantExprClass: {
    // FIXME: We should be able to return "true" here, but it can lead to extra
    // error messages. E.g. in Sema/array-init.c.
    const Expr *Exp = cast<ConstantExpr>(this)->getSubExpr();
    return Exp->isConstantInitializer(Ctx, false, Culprit);
  }
  case CompoundLiteralExprClass: {
    // This handles gcc's extension that allows global initializers like
    // "struct x {int x;} x = (struct x) {};".
    // FIXME: This accepts other cases it shouldn't!
    const Expr *Exp = cast<CompoundLiteralExpr>(this)->getInitializer();
    return Exp->isConstantInitializer(Ctx, false, Culprit);
  }
  case DesignatedInitUpdateExprClass: {
    const DesignatedInitUpdateExpr *DIUE = cast<DesignatedInitUpdateExpr>(this);
    return DIUE->getBase()->isConstantInitializer(Ctx, false, Culprit) &&
           DIUE->getUpdater()->isConstantInitializer(Ctx, false, Culprit);
  }
  case InitListExprClass: {
    // C++ [dcl.init.aggr]p2:
    //   The elements of an aggregate are:
    //   - for an array, the array elements in increasing subscript order, or
    //   - for a class, the direct base classes in declaration order, followed
    //     by the direct non-static data members (11.4) that are not members of
    //     an anonymous union, in declaration order.
    const InitListExpr *ILE = cast<InitListExpr>(this);
    assert(ILE->isSemanticForm() && "InitListExpr must be in semantic form");
    if (ILE->getType()->isArrayType()) {
      unsigned numInits = ILE->getNumInits();
      for (unsigned i = 0; i < numInits; i++) {
        if (!ILE->getInit(i)->isConstantInitializer(Ctx, false, Culprit))
          return false;
      }
      return true;
    }

    if (ILE->getType()->isRecordType()) {
      unsigned ElementNo = 0;
      RecordDecl *RD = ILE->getType()->castAs<RecordType>()->getDecl();

      // In C++17, bases were added to the list of members used by aggregate
      // initialization.
      if (const auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
        for (unsigned i = 0, e = CXXRD->getNumBases(); i < e; i++) {
          if (ElementNo < ILE->getNumInits()) {
            const Expr *Elt = ILE->getInit(ElementNo++);
            if (!Elt->isConstantInitializer(Ctx, false, Culprit))
              return false;
          }
        }
      }

      for (const auto *Field : RD->fields()) {
        // If this is a union, skip all the fields that aren't being initialized.
        if (RD->isUnion() && ILE->getInitializedFieldInUnion() != Field)
          continue;

        // Don't emit anonymous bitfields, they just affect layout.
        if (Field->isUnnamedBitField())
          continue;

        if (ElementNo < ILE->getNumInits()) {
          const Expr *Elt = ILE->getInit(ElementNo++);
          if (Field->isBitField()) {
            // Bitfields have to evaluate to an integer.
            EvalResult Result;
            if (!Elt->EvaluateAsInt(Result, Ctx)) {
              if (Culprit)
                *Culprit = Elt;
              return false;
            }
          } else {
            bool RefType = Field->getType()->isReferenceType();
            if (!Elt->isConstantInitializer(Ctx, RefType, Culprit))
              return false;
          }
        }
      }
      return true;
    }

    break;
  }
  case ImplicitValueInitExprClass:
  case NoInitExprClass:
    return true;
  case ParenExprClass:
    return cast<ParenExpr>(this)->getSubExpr()
      ->isConstantInitializer(Ctx, IsForRef, Culprit);
  case GenericSelectionExprClass:
    return cast<GenericSelectionExpr>(this)->getResultExpr()
      ->isConstantInitializer(Ctx, IsForRef, Culprit);
  case ChooseExprClass:
    if (cast<ChooseExpr>(this)->isConditionDependent()) {
      if (Culprit)
        *Culprit = this;
      return false;
    }
    return cast<ChooseExpr>(this)->getChosenSubExpr()
      ->isConstantInitializer(Ctx, IsForRef, Culprit);
  case UnaryOperatorClass: {
    const UnaryOperator* Exp = cast<UnaryOperator>(this);
    if (Exp->getOpcode() == UO_Extension)
      return Exp->getSubExpr()->isConstantInitializer(Ctx, false, Culprit);
    break;
  }
  case PackIndexingExprClass: {
    return cast<PackIndexingExpr>(this)
        ->getSelectedExpr()
        ->isConstantInitializer(Ctx, false, Culprit);
  }
  case CXXFunctionalCastExprClass:
  case CXXStaticCastExprClass:
  case ImplicitCastExprClass:
  case CStyleCastExprClass:
  case ObjCBridgedCastExprClass:
  case CXXDynamicCastExprClass:
  case CXXReinterpretCastExprClass:
  case CXXAddrspaceCastExprClass:
  case CXXConstCastExprClass: {
    const CastExpr *CE = cast<CastExpr>(this);

    // Handle misc casts we want to ignore.
    if (CE->getCastKind() == CK_NoOp ||
        CE->getCastKind() == CK_LValueToRValue ||
        CE->getCastKind() == CK_ToUnion ||
        CE->getCastKind() == CK_ConstructorConversion ||
        CE->getCastKind() == CK_NonAtomicToAtomic ||
        CE->getCastKind() == CK_AtomicToNonAtomic ||
        CE->getCastKind() == CK_NullToPointer ||
        CE->getCastKind() == CK_IntToOCLSampler)
      return CE->getSubExpr()->isConstantInitializer(Ctx, false, Culprit);

    break;
  }
  case MaterializeTemporaryExprClass:
    return cast<MaterializeTemporaryExpr>(this)
        ->getSubExpr()
        ->isConstantInitializer(Ctx, false, Culprit);

  case SubstNonTypeTemplateParmExprClass:
    return cast<SubstNonTypeTemplateParmExpr>(this)->getReplacement()
      ->isConstantInitializer(Ctx, false, Culprit);
  case CXXDefaultArgExprClass:
    return cast<CXXDefaultArgExpr>(this)->getExpr()
      ->isConstantInitializer(Ctx, false, Culprit);
  case CXXDefaultInitExprClass:
    return cast<CXXDefaultInitExpr>(this)->getExpr()
      ->isConstantInitializer(Ctx, false, Culprit);
  }
  // Allow certain forms of UB in constant initializers: signed integer
  // overflow and floating-point division by zero. We'll give a warning on
  // these, but they're common enough that we have to accept them.
  if (isEvaluatable(Ctx, SE_AllowUndefinedBehavior))
    return true;
  if (Culprit)
    *Culprit = this;
  return false;
}

bool CallExpr::isBuiltinAssumeFalse(const ASTContext &Ctx) const {
  unsigned BuiltinID = getBuiltinCallee();
  if (BuiltinID != Builtin::BI__assume &&
      BuiltinID != Builtin::BI__builtin_assume)
    return false;

  const Expr* Arg = getArg(0);
  bool ArgVal;
  return !Arg->isValueDependent() &&
         Arg->EvaluateAsBooleanCondition(ArgVal, Ctx) && !ArgVal;
}

bool CallExpr::isCallToStdMove() const {
  return getBuiltinCallee() == Builtin::BImove;
}

namespace {
  /// Look for any side effects within a Stmt.
  class SideEffectFinder : public ConstEvaluatedExprVisitor<SideEffectFinder> {
    typedef ConstEvaluatedExprVisitor<SideEffectFinder> Inherited;
    const bool IncludePossibleEffects;
    bool HasSideEffects;

  public:
    explicit SideEffectFinder(const ASTContext &Context, bool IncludePossible)
      : Inherited(Context),
        IncludePossibleEffects(IncludePossible), HasSideEffects(false) { }

    bool hasSideEffects() const { return HasSideEffects; }

    void VisitDecl(const Decl *D) {
      if (!D)
        return;

      // We assume the caller checks subexpressions (eg, the initializer, VLA
      // bounds) for side-effects on our behalf.
      if (auto *VD = dyn_cast<VarDecl>(D)) {
        // Registering a destructor is a side-effect.
        if (IncludePossibleEffects && VD->isThisDeclarationADefinition() &&
            VD->needsDestruction(Context))
          HasSideEffects = true;
      }
    }

    void VisitDeclStmt(const DeclStmt *DS) {
      for (auto *D : DS->decls())
        VisitDecl(D);
      Inherited::VisitDeclStmt(DS);
    }

    void VisitExpr(const Expr *E) {
      if (!HasSideEffects &&
          E->HasSideEffects(Context, IncludePossibleEffects))
        HasSideEffects = true;
    }
  };
}

bool Expr::HasSideEffects(const ASTContext &Ctx,
                          bool IncludePossibleEffects) const {
  // In circumstances where we care about definite side effects instead of
  // potential side effects, we want to ignore expressions that are part of a
  // macro expansion as a potential side effect.
  if (!IncludePossibleEffects && getExprLoc().isMacroID())
    return false;

  switch (getStmtClass()) {
  case NoStmtClass:
  #define ABSTRACT_STMT(Type)
  #define STMT(Type, Base) case Type##Class:
  #define EXPR(Type, Base)
  #include "clang/AST/StmtNodes.inc"
    llvm_unreachable("unexpected Expr kind");

  case DependentScopeDeclRefExprClass:
  case CXXUnresolvedConstructExprClass:
  case CXXDependentScopeMemberExprClass:
  case UnresolvedLookupExprClass:
  case UnresolvedMemberExprClass:
  case PackExpansionExprClass:
  case SubstNonTypeTemplateParmPackExprClass:
  case FunctionParmPackExprClass:
  case TypoExprClass:
  case RecoveryExprClass:
  case CXXFoldExprClass:
    // Make a conservative assumption for dependent nodes.
    return IncludePossibleEffects;

  case DeclRefExprClass:
  case ObjCIvarRefExprClass:
  case PredefinedExprClass:
  case IntegerLiteralClass:
  case FixedPointLiteralClass:
  case FloatingLiteralClass:
  case ImaginaryLiteralClass:
  case StringLiteralClass:
  case CharacterLiteralClass:
  case OffsetOfExprClass:
  case ImplicitValueInitExprClass:
  case UnaryExprOrTypeTraitExprClass:
  case AddrLabelExprClass:
  case GNUNullExprClass:
  case ArrayInitIndexExprClass:
  case NoInitExprClass:
  case CXXBoolLiteralExprClass:
  case CXXNullPtrLiteralExprClass:
  case CXXThisExprClass:
  case CXXScalarValueInitExprClass:
  case TypeTraitExprClass:
  case ArrayTypeTraitExprClass:
  case ExpressionTraitExprClass:
  case CXXNoexceptExprClass:
  case SizeOfPackExprClass:
  case ObjCStringLiteralClass:
  case ObjCEncodeExprClass:
  case ObjCBoolLiteralExprClass:
  case ObjCAvailabilityCheckExprClass:
  case CXXUuidofExprClass:
  case OpaqueValueExprClass:
  case SourceLocExprClass:
  case EmbedExprClass:
  case ConceptSpecializationExprClass:
  case RequiresExprClass:
  case SYCLUniqueStableNameExprClass:
  case PackIndexingExprClass:
    // These never have a side-effect.
    return false;

  case ConstantExprClass:
    // FIXME: Move this into the "return false;" block above.
    return cast<ConstantExpr>(this)->getSubExpr()->HasSideEffects(
        Ctx, IncludePossibleEffects);

  case CallExprClass:
  case CXXOperatorCallExprClass:
  case CXXMemberCallExprClass:
  case CUDAKernelCallExprClass:
  case UserDefinedLiteralClass: {
    // We don't know a call definitely has side effects, except for calls
    // to pure/const functions that definitely don't.
    // If the call itself is considered side-effect free, check the operands.
    const Decl *FD = cast<CallExpr>(this)->getCalleeDecl();
    bool IsPure = FD && (FD->hasAttr<ConstAttr>() || FD->hasAttr<PureAttr>());
    if (IsPure || !IncludePossibleEffects)
      break;
    return true;
  }

  case BlockExprClass:
  case CXXBindTemporaryExprClass:
    if (!IncludePossibleEffects)
      break;
    return true;

  case MSPropertyRefExprClass:
  case MSPropertySubscriptExprClass:
  case CompoundAssignOperatorClass:
  case VAArgExprClass:
  case AtomicExprClass:
  case CXXThrowExprClass:
  case CXXNewExprClass:
  case CXXDeleteExprClass:
  case CoawaitExprClass:
  case DependentCoawaitExprClass:
  case CoyieldExprClass:
    // These always have a side-effect.
    return true;

  case StmtExprClass: {
    // StmtExprs have a side-effect if any substatement does.
    SideEffectFinder Finder(Ctx, IncludePossibleEffects);
    Finder.Visit(cast<StmtExpr>(this)->getSubStmt());
    return Finder.hasSideEffects();
  }

  case ExprWithCleanupsClass:
    if (IncludePossibleEffects)
      if (cast<ExprWithCleanups>(this)->cleanupsHaveSideEffects())
        return true;
    break;

  case ParenExprClass:
  case ArraySubscriptExprClass:
  case MatrixSubscriptExprClass:
  case ArraySectionExprClass:
  case OMPArrayShapingExprClass:
  case OMPIteratorExprClass:
  case MemberExprClass:
  case ConditionalOperatorClass:
  case BinaryConditionalOperatorClass:
  case CompoundLiteralExprClass:
  case ExtVectorElementExprClass:
  case DesignatedInitExprClass:
  case DesignatedInitUpdateExprClass:
  case ArrayInitLoopExprClass:
  case ParenListExprClass:
  case CXXPseudoDestructorExprClass:
  case CXXRewrittenBinaryOperatorClass:
  case CXXStdInitializerListExprClass:
  case SubstNonTypeTemplateParmExprClass:
  case MaterializeTemporaryExprClass:
  case ShuffleVectorExprClass:
  case ConvertVectorExprClass:
  case AsTypeExprClass:
  case CXXParenListInitExprClass:
    // These have a side-effect if any subexpression does.
    break;

  case UnaryOperatorClass:
    if (cast<UnaryOperator>(this)->isIncrementDecrementOp())
      return true;
    break;

  case BinaryOperatorClass:
    if (cast<BinaryOperator>(this)->isAssignmentOp())
      return true;
    break;

  case InitListExprClass:
    // FIXME: The children for an InitListExpr doesn't include the array filler.
    if (const Expr *E = cast<InitListExpr>(this)->getArrayFiller())
      if (E->HasSideEffects(Ctx, IncludePossibleEffects))
        return true;
    break;

  case GenericSelectionExprClass:
    return cast<GenericSelectionExpr>(this)->getResultExpr()->
        HasSideEffects(Ctx, IncludePossibleEffects);

  case ChooseExprClass:
    return cast<ChooseExpr>(this)->getChosenSubExpr()->HasSideEffects(
        Ctx, IncludePossibleEffects);

  case CXXDefaultArgExprClass:
    return cast<CXXDefaultArgExpr>(this)->getExpr()->HasSideEffects(
        Ctx, IncludePossibleEffects);

  case CXXDefaultInitExprClass: {
    const FieldDecl *FD = cast<CXXDefaultInitExpr>(this)->getField();
    if (const Expr *E = FD->getInClassInitializer())
      return E->HasSideEffects(Ctx, IncludePossibleEffects);
    // If we've not yet parsed the initializer, assume it has side-effects.
    return true;
  }

  case CXXDynamicCastExprClass: {
    // A dynamic_cast expression has side-effects if it can throw.
    const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(this);
    if (DCE->getTypeAsWritten()->isReferenceType() &&
        DCE->getCastKind() == CK_Dynamic)
      return true;
    }
    [[fallthrough]];
  case ImplicitCastExprClass:
  case CStyleCastExprClass:
  case CXXStaticCastExprClass:
  case CXXReinterpretCastExprClass:
  case CXXConstCastExprClass:
  case CXXAddrspaceCastExprClass:
  case CXXFunctionalCastExprClass:
  case BuiltinBitCastExprClass: {
    // While volatile reads are side-effecting in both C and C++, we treat them
    // as having possible (not definite) side-effects. This allows idiomatic
    // code to behave without warning, such as sizeof(*v) for a volatile-
    // qualified pointer.
    if (!IncludePossibleEffects)
      break;

    const CastExpr *CE = cast<CastExpr>(this);
    if (CE->getCastKind() == CK_LValueToRValue &&
        CE->getSubExpr()->getType().isVolatileQualified())
      return true;
    break;
  }

  case CXXTypeidExprClass: {
    const auto *TE = cast<CXXTypeidExpr>(this);
    if (!TE->isPotentiallyEvaluated())
      return false;

    // If this type id expression can throw because of a null pointer, that is a
    // side-effect independent of if the operand has a side-effect
    if (IncludePossibleEffects && TE->hasNullCheck())
      return true;

    break;
  }

  case CXXConstructExprClass:
  case CXXTemporaryObjectExprClass: {
    const CXXConstructExpr *CE = cast<CXXConstructExpr>(this);
    if (!CE->getConstructor()->isTrivial() && IncludePossibleEffects)
      return true;
    // A trivial constructor does not add any side-effects of its own. Just look
    // at its arguments.
    break;
  }

  case CXXInheritedCtorInitExprClass: {
    const auto *ICIE = cast<CXXInheritedCtorInitExpr>(this);
    if (!ICIE->getConstructor()->isTrivial() && IncludePossibleEffects)
      return true;
    break;
  }

  case LambdaExprClass: {
    const LambdaExpr *LE = cast<LambdaExpr>(this);
    for (Expr *E : LE->capture_inits())
      if (E && E->HasSideEffects(Ctx, IncludePossibleEffects))
        return true;
    return false;
  }

  case PseudoObjectExprClass: {
    // Only look for side-effects in the semantic form, and look past
    // OpaqueValueExpr bindings in that form.
    const PseudoObjectExpr *PO = cast<PseudoObjectExpr>(this);
    for (PseudoObjectExpr::const_semantics_iterator I = PO->semantics_begin(),
                                                    E = PO->semantics_end();
         I != E; ++I) {
      const Expr *Subexpr = *I;
      if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Subexpr))
        Subexpr = OVE->getSourceExpr();
      if (Subexpr->HasSideEffects(Ctx, IncludePossibleEffects))
        return true;
    }
    return false;
  }

  case ObjCBoxedExprClass:
  case ObjCArrayLiteralClass:
  case ObjCDictionaryLiteralClass:
  case ObjCSelectorExprClass:
  case ObjCProtocolExprClass:
  case ObjCIsaExprClass:
  case ObjCIndirectCopyRestoreExprClass:
  case ObjCSubscriptRefExprClass:
  case ObjCBridgedCastExprClass:
  case ObjCMessageExprClass:
  case ObjCPropertyRefExprClass:
  // FIXME: Classify these cases better.
    if (IncludePossibleEffects)
      return true;
    break;
  }

  // Recurse to children.
  for (const Stmt *SubStmt : children())
    if (SubStmt &&
        cast<Expr>(SubStmt)->HasSideEffects(Ctx, IncludePossibleEffects))
      return true;

  return false;
}

FPOptions Expr::getFPFeaturesInEffect(const LangOptions &LO) const {
  if (auto Call = dyn_cast<CallExpr>(this))
    return Call->getFPFeaturesInEffect(LO);
  if (auto UO = dyn_cast<UnaryOperator>(this))
    return UO->getFPFeaturesInEffect(LO);
  if (auto BO = dyn_cast<BinaryOperator>(this))
    return BO->getFPFeaturesInEffect(LO);
  if (auto Cast = dyn_cast<CastExpr>(this))
    return Cast->getFPFeaturesInEffect(LO);
  return FPOptions::defaultWithoutTrailingStorage(LO);
}

namespace {
  /// Look for a call to a non-trivial function within an expression.
  class NonTrivialCallFinder : public ConstEvaluatedExprVisitor<NonTrivialCallFinder>
  {
    typedef ConstEvaluatedExprVisitor<NonTrivialCallFinder> Inherited;

    bool NonTrivial;

  public:
    explicit NonTrivialCallFinder(const ASTContext &Context)
      : Inherited(Context), NonTrivial(false) { }

    bool hasNonTrivialCall() const { return NonTrivial; }

    void VisitCallExpr(const CallExpr *E) {
      if (const CXXMethodDecl *Method
          = dyn_cast_or_null<const CXXMethodDecl>(E->getCalleeDecl())) {
        if (Method->isTrivial()) {
          // Recurse to children of the call.
          Inherited::VisitStmt(E);
          return;
        }
      }

      NonTrivial = true;
    }

    void VisitCXXConstructExpr(const CXXConstructExpr *E) {
      if (E->getConstructor()->isTrivial()) {
        // Recurse to children of the call.
        Inherited::VisitStmt(E);
        return;
      }

      NonTrivial = true;
    }

    void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
      // Destructor of the temporary might be null if destructor declaration
      // is not valid.
      if (const CXXDestructorDecl *DtorDecl =
              E->getTemporary()->getDestructor()) {
        if (DtorDecl->isTrivial()) {
          Inherited::VisitStmt(E);
          return;
        }
      }

      NonTrivial = true;
    }
  };
}

bool Expr::hasNonTrivialCall(const ASTContext &Ctx) const {
  NonTrivialCallFinder Finder(Ctx);
  Finder.Visit(this);
  return Finder.hasNonTrivialCall();
}

/// isNullPointerConstant - C99 6.3.2.3p3 - Return whether this is a null
/// pointer constant or not, as well as the specific kind of constant detected.
/// Null pointer constants can be integer constant expressions with the
/// value zero, casts of zero to void*, nullptr (C++0X), or __null
/// (a GNU extension).
Expr::NullPointerConstantKind
Expr::isNullPointerConstant(ASTContext &Ctx,
                            NullPointerConstantValueDependence NPC) const {
  if (isValueDependent() &&
      (!Ctx.getLangOpts().CPlusPlus11 || Ctx.getLangOpts().MSVCCompat)) {
    // Error-dependent expr should never be a null pointer.
    if (containsErrors())
      return NPCK_NotNull;
    switch (NPC) {
    case NPC_NeverValueDependent:
      llvm_unreachable("Unexpected value dependent expression!");
    case NPC_ValueDependentIsNull:
      if (isTypeDependent() || getType()->isIntegralType(Ctx))
        return NPCK_ZeroExpression;
      else
        return NPCK_NotNull;

    case NPC_ValueDependentIsNotNull:
      return NPCK_NotNull;
    }
  }

  // Strip off a cast to void*, if it exists. Except in C++.
  if (const ExplicitCastExpr *CE = dyn_cast<ExplicitCastExpr>(this)) {
    if (!Ctx.getLangOpts().CPlusPlus) {
      // Check that it is a cast to void*.
      if (const PointerType *PT = CE->getType()->getAs<PointerType>()) {
        QualType Pointee = PT->getPointeeType();
        Qualifiers Qs = Pointee.getQualifiers();
        // Only (void*)0 or equivalent are treated as nullptr. If pointee type
        // has non-default address space it is not treated as nullptr.
        // (__generic void*)0 in OpenCL 2.0 should not be treated as nullptr
        // since it cannot be assigned to a pointer to constant address space.
        if (Ctx.getLangOpts().OpenCL &&
            Pointee.getAddressSpace() == Ctx.getDefaultOpenCLPointeeAddrSpace())
          Qs.removeAddressSpace();

        if (Pointee->isVoidType() && Qs.empty() && // to void*
            CE->getSubExpr()->getType()->isIntegerType()) // from int
          return CE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
      }
    }
  } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
    // Ignore the ImplicitCastExpr type entirely.
    return ICE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
    // Accept ((void*)0) as a null pointer constant, as many other
    // implementations do.
    return PE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (const GenericSelectionExpr *GE =
               dyn_cast<GenericSelectionExpr>(this)) {
    if (GE->isResultDependent())
      return NPCK_NotNull;
    return GE->getResultExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (const ChooseExpr *CE = dyn_cast<ChooseExpr>(this)) {
    if (CE->isConditionDependent())
      return NPCK_NotNull;
    return CE->getChosenSubExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (const CXXDefaultArgExpr *DefaultArg
               = dyn_cast<CXXDefaultArgExpr>(this)) {
    // See through default argument expressions.
    return DefaultArg->getExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (const CXXDefaultInitExpr *DefaultInit
               = dyn_cast<CXXDefaultInitExpr>(this)) {
    // See through default initializer expressions.
    return DefaultInit->getExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (isa<GNUNullExpr>(this)) {
    // The GNU __null extension is always a null pointer constant.
    return NPCK_GNUNull;
  } else if (const MaterializeTemporaryExpr *M
                                   = dyn_cast<MaterializeTemporaryExpr>(this)) {
    return M->getSubExpr()->isNullPointerConstant(Ctx, NPC);
  } else if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(this)) {
    if (const Expr *Source = OVE->getSourceExpr())
      return Source->isNullPointerConstant(Ctx, NPC);
  }

  // If the expression has no type information, it cannot be a null pointer
  // constant.
  if (getType().isNull())
    return NPCK_NotNull;

  // C++11/C23 nullptr_t is always a null pointer constant.
  if (getType()->isNullPtrType())
    return NPCK_CXX11_nullptr;

  if (const RecordType *UT = getType()->getAsUnionType())
    if (!Ctx.getLangOpts().CPlusPlus11 &&
        UT && UT->getDecl()->hasAttr<TransparentUnionAttr>())
      if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(this)){
        const Expr *InitExpr = CLE->getInitializer();
        if (const InitListExpr *ILE = dyn_cast<InitListExpr>(InitExpr))
          return ILE->getInit(0)->isNullPointerConstant(Ctx, NPC);
      }
  // This expression must be an integer type.
  if (!getType()->isIntegerType() ||
      (Ctx.getLangOpts().CPlusPlus && getType()->isEnumeralType()))
    return NPCK_NotNull;

  if (Ctx.getLangOpts().CPlusPlus11) {
    // C++11 [conv.ptr]p1: A null pointer constant is an integer literal with
    // value zero or a prvalue of type std::nullptr_t.
    // Microsoft mode permits C++98 rules reflecting MSVC behavior.
    const IntegerLiteral *Lit = dyn_cast<IntegerLiteral>(this);
    if (Lit && !Lit->getValue())
      return NPCK_ZeroLiteral;
    if (!Ctx.getLangOpts().MSVCCompat || !isCXX98IntegralConstantExpr(Ctx))
      return NPCK_NotNull;
  } else {
    // If we have an integer constant expression, we need to *evaluate* it and
    // test for the value 0.
    if (!isIntegerConstantExpr(Ctx))
      return NPCK_NotNull;
  }

  if (EvaluateKnownConstInt(Ctx) != 0)
    return NPCK_NotNull;

  if (isa<IntegerLiteral>(this))
    return NPCK_ZeroLiteral;
  return NPCK_ZeroExpression;
}

/// If this expression is an l-value for an Objective C
/// property, find the underlying property reference expression.
const ObjCPropertyRefExpr *Expr::getObjCProperty() const {
  const Expr *E = this;
  while (true) {
    assert((E->isLValue() && E->getObjectKind() == OK_ObjCProperty) &&
           "expression is not a property reference");
    E = E->IgnoreParenCasts();
    if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
      if (BO->getOpcode() == BO_Comma) {
        E = BO->getRHS();
        continue;
      }
    }

    break;
  }

  return cast<ObjCPropertyRefExpr>(E);
}

bool Expr::isObjCSelfExpr() const {
  const Expr *E = IgnoreParenImpCasts();

  const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
  if (!DRE)
    return false;

  const ImplicitParamDecl *Param = dyn_cast<ImplicitParamDecl>(DRE->getDecl());
  if (!Param)
    return false;

  const ObjCMethodDecl *M = dyn_cast<ObjCMethodDecl>(Param->getDeclContext());
  if (!M)
    return false;

  return M->getSelfDecl() == Param;
}

FieldDecl *Expr::getSourceBitField() {
  Expr *E = this->IgnoreParens();

  while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
    if (ICE->getCastKind() == CK_LValueToRValue ||
        (ICE->isGLValue() && ICE->getCastKind() == CK_NoOp))
      E = ICE->getSubExpr()->IgnoreParens();
    else
      break;
  }

  if (MemberExpr *MemRef = dyn_cast<MemberExpr>(E))
    if (FieldDecl *Field = dyn_cast<FieldDecl>(MemRef->getMemberDecl()))
      if (Field->isBitField())
        return Field;

  if (ObjCIvarRefExpr *IvarRef = dyn_cast<ObjCIvarRefExpr>(E)) {
    FieldDecl *Ivar = IvarRef->getDecl();
    if (Ivar->isBitField())
      return Ivar;
  }

  if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E)) {
    if (FieldDecl *Field = dyn_cast<FieldDecl>(DeclRef->getDecl()))
      if (Field->isBitField())
        return Field;

    if (BindingDecl *BD = dyn_cast<BindingDecl>(DeclRef->getDecl()))
      if (Expr *E = BD->getBinding())
        return E->getSourceBitField();
  }

  if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(E)) {
    if (BinOp->isAssignmentOp() && BinOp->getLHS())
      return BinOp->getLHS()->getSourceBitField();

    if (BinOp->getOpcode() == BO_Comma && BinOp->getRHS())
      return BinOp->getRHS()->getSourceBitField();
  }

  if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E))
    if (UnOp->isPrefix() && UnOp->isIncrementDecrementOp())
      return UnOp->getSubExpr()->getSourceBitField();

  return nullptr;
}

EnumConstantDecl *Expr::getEnumConstantDecl() {
  Expr *E = this->IgnoreParenImpCasts();
  if (auto *DRE = dyn_cast<DeclRefExpr>(E))
    return dyn_cast<EnumConstantDecl>(DRE->getDecl());
  return nullptr;
}

bool Expr::refersToVectorElement() const {
  // FIXME: Why do we not just look at the ObjectKind here?
  const Expr *E = this->IgnoreParens();

  while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
    if (ICE->isGLValue() && ICE->getCastKind() == CK_NoOp)
      E = ICE->getSubExpr()->IgnoreParens();
    else
      break;
  }

  if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(E))
    return ASE->getBase()->getType()->isVectorType();

  if (isa<ExtVectorElementExpr>(E))
    return true;

  if (auto *DRE = dyn_cast<DeclRefExpr>(E))
    if (auto *BD = dyn_cast<BindingDecl>(DRE->getDecl()))
      if (auto *E = BD->getBinding())
        return E->refersToVectorElement();

  return false;
}

bool Expr::refersToGlobalRegisterVar() const {
  const Expr *E = this->IgnoreParenImpCasts();

  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
    if (const auto *VD = dyn_cast<VarDecl>(DRE->getDecl()))
      if (VD->getStorageClass() == SC_Register &&
          VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())
        return true;

  return false;
}

bool Expr::isSameComparisonOperand(const Expr* E1, const Expr* E2) {
  E1 = E1->IgnoreParens();
  E2 = E2->IgnoreParens();

  if (E1->getStmtClass() != E2->getStmtClass())
    return false;

  switch (E1->getStmtClass()) {
    default:
      return false;
    case CXXThisExprClass:
      return true;
    case DeclRefExprClass: {
      // DeclRefExpr without an ImplicitCastExpr can happen for integral
      // template parameters.
      const auto *DRE1 = cast<DeclRefExpr>(E1);
      const auto *DRE2 = cast<DeclRefExpr>(E2);
      return DRE1->isPRValue() && DRE2->isPRValue() &&
             DRE1->getDecl() == DRE2->getDecl();
    }
    case ImplicitCastExprClass: {
      // Peel off implicit casts.
      while (true) {
        const auto *ICE1 = dyn_cast<ImplicitCastExpr>(E1);
        const auto *ICE2 = dyn_cast<ImplicitCastExpr>(E2);
        if (!ICE1 || !ICE2)
          return false;
        if (ICE1->getCastKind() != ICE2->getCastKind())
          return false;
        E1 = ICE1->getSubExpr()->IgnoreParens();
        E2 = ICE2->getSubExpr()->IgnoreParens();
        // The final cast must be one of these types.
        if (ICE1->getCastKind() == CK_LValueToRValue ||
            ICE1->getCastKind() == CK_ArrayToPointerDecay ||
            ICE1->getCastKind() == CK_FunctionToPointerDecay) {
          break;
        }
      }

      const auto *DRE1 = dyn_cast<DeclRefExpr>(E1);
      const auto *DRE2 = dyn_cast<DeclRefExpr>(E2);
      if (DRE1 && DRE2)
        return declaresSameEntity(DRE1->getDecl(), DRE2->getDecl());

      const auto *Ivar1 = dyn_cast<ObjCIvarRefExpr>(E1);
      const auto *Ivar2 = dyn_cast<ObjCIvarRefExpr>(E2);
      if (Ivar1 && Ivar2) {
        return Ivar1->isFreeIvar() && Ivar2->isFreeIvar() &&
               declaresSameEntity(Ivar1->getDecl(), Ivar2->getDecl());
      }

      const auto *Array1 = dyn_cast<ArraySubscriptExpr>(E1);
      const auto *Array2 = dyn_cast<ArraySubscriptExpr>(E2);
      if (Array1 && Array2) {
        if (!isSameComparisonOperand(Array1->getBase(), Array2->getBase()))
          return false;

        auto Idx1 = Array1->getIdx();
        auto Idx2 = Array2->getIdx();
        const auto Integer1 = dyn_cast<IntegerLiteral>(Idx1);
        const auto Integer2 = dyn_cast<IntegerLiteral>(Idx2);
        if (Integer1 && Integer2) {
          if (!llvm::APInt::isSameValue(Integer1->getValue(),
                                        Integer2->getValue()))
            return false;
        } else {
          if (!isSameComparisonOperand(Idx1, Idx2))
            return false;
        }

        return true;
      }

      // Walk the MemberExpr chain.
      while (isa<MemberExpr>(E1) && isa<MemberExpr>(E2)) {
        const auto *ME1 = cast<MemberExpr>(E1);
        const auto *ME2 = cast<MemberExpr>(E2);
        if (!declaresSameEntity(ME1->getMemberDecl(), ME2->getMemberDecl()))
          return false;
        if (const auto *D = dyn_cast<VarDecl>(ME1->getMemberDecl()))
          if (D->isStaticDataMember())
            return true;
        E1 = ME1->getBase()->IgnoreParenImpCasts();
        E2 = ME2->getBase()->IgnoreParenImpCasts();
      }

      if (isa<CXXThisExpr>(E1) && isa<CXXThisExpr>(E2))
        return true;

      // A static member variable can end the MemberExpr chain with either
      // a MemberExpr or a DeclRefExpr.
      auto getAnyDecl = [](const Expr *E) -> const ValueDecl * {
        if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
          return DRE->getDecl();
        if (const auto *ME = dyn_cast<MemberExpr>(E))
          return ME->getMemberDecl();
        return nullptr;
      };

      const ValueDecl *VD1 = getAnyDecl(E1);
      const ValueDecl *VD2 = getAnyDecl(E2);
      return declaresSameEntity(VD1, VD2);
    }
  }
}

/// isArrow - Return true if the base expression is a pointer to vector,
/// return false if the base expression is a vector.
bool ExtVectorElementExpr::isArrow() const {
  return getBase()->getType()->isPointerType();
}

unsigned ExtVectorElementExpr::getNumElements() const {
  if (const VectorType *VT = getType()->getAs<VectorType>())
    return VT->getNumElements();
  return 1;
}

/// containsDuplicateElements - Return true if any element access is repeated.
bool ExtVectorElementExpr::containsDuplicateElements() const {
  // FIXME: Refactor this code to an accessor on the AST node which returns the
  // "type" of component access, and share with code below and in Sema.
  StringRef Comp = Accessor->getName();

  // Halving swizzles do not contain duplicate elements.
  if (Comp == "hi" || Comp == "lo" || Comp == "even" || Comp == "odd")
    return false;

  // Advance past s-char prefix on hex swizzles.
  if (Comp[0] == 's' || Comp[0] == 'S')
    Comp = Comp.substr(1);

  for (unsigned i = 0, e = Comp.size(); i != e; ++i)
    if (Comp.substr(i + 1).contains(Comp[i]))
        return true;

  return false;
}

/// getEncodedElementAccess - We encode the fields as a llvm ConstantArray.
void ExtVectorElementExpr::getEncodedElementAccess(
    SmallVectorImpl<uint32_t> &Elts) const {
  StringRef Comp = Accessor->getName();
  bool isNumericAccessor = false;
  if (Comp[0] == 's' || Comp[0] == 'S') {
    Comp = Comp.substr(1);
    isNumericAccessor = true;
  }

  bool isHi =   Comp == "hi";
  bool isLo =   Comp == "lo";
  bool isEven = Comp == "even";
  bool isOdd  = Comp == "odd";

  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
    uint64_t Index;

    if (isHi)
      Index = e + i;
    else if (isLo)
      Index = i;
    else if (isEven)
      Index = 2 * i;
    else if (isOdd)
      Index = 2 * i + 1;
    else
      Index = ExtVectorType::getAccessorIdx(Comp[i], isNumericAccessor);

    Elts.push_back(Index);
  }
}

ShuffleVectorExpr::ShuffleVectorExpr(const ASTContext &C, ArrayRef<Expr *> args,
                                     QualType Type, SourceLocation BLoc,
                                     SourceLocation RP)
    : Expr(ShuffleVectorExprClass, Type, VK_PRValue, OK_Ordinary),
      BuiltinLoc(BLoc), RParenLoc(RP), NumExprs(args.size()) {
  SubExprs = new (C) Stmt*[args.size()];
  for (unsigned i = 0; i != args.size(); i++)
    SubExprs[i] = args[i];

  setDependence(computeDependence(this));
}

void ShuffleVectorExpr::setExprs(const ASTContext &C, ArrayRef<Expr *> Exprs) {
  if (SubExprs) C.Deallocate(SubExprs);

  this->NumExprs = Exprs.size();
  SubExprs = new (C) Stmt*[NumExprs];
  memcpy(SubExprs, Exprs.data(), sizeof(Expr *) * Exprs.size());
}

GenericSelectionExpr::GenericSelectionExpr(
    const ASTContext &, SourceLocation GenericLoc, Expr *ControllingExpr,
    ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
    SourceLocation DefaultLoc, SourceLocation RParenLoc,
    bool ContainsUnexpandedParameterPack, unsigned ResultIndex)
    : Expr(GenericSelectionExprClass, AssocExprs[ResultIndex]->getType(),
           AssocExprs[ResultIndex]->getValueKind(),
           AssocExprs[ResultIndex]->getObjectKind()),
      NumAssocs(AssocExprs.size()), ResultIndex(ResultIndex),
      IsExprPredicate(true), DefaultLoc(DefaultLoc), RParenLoc(RParenLoc) {
  assert(AssocTypes.size() == AssocExprs.size() &&
         "Must have the same number of association expressions"
         " and TypeSourceInfo!");
  assert(ResultIndex < NumAssocs && "ResultIndex is out-of-bounds!");

  GenericSelectionExprBits.GenericLoc = GenericLoc;
  getTrailingObjects<Stmt *>()[getIndexOfControllingExpression()] =
      ControllingExpr;
  std::copy(AssocExprs.begin(), AssocExprs.end(),
            getTrailingObjects<Stmt *>() + getIndexOfStartOfAssociatedExprs());
  std::copy(AssocTypes.begin(), AssocTypes.end(),
            getTrailingObjects<TypeSourceInfo *>() +
                getIndexOfStartOfAssociatedTypes());

  setDependence(computeDependence(this, ContainsUnexpandedParameterPack));
}

GenericSelectionExpr::GenericSelectionExpr(
    const ASTContext &, SourceLocation GenericLoc,
    TypeSourceInfo *ControllingType, ArrayRef<TypeSourceInfo *> AssocTypes,
    ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
    SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack,
    unsigned ResultIndex)
    : Expr(GenericSelectionExprClass, AssocExprs[ResultIndex]->getType(),
           AssocExprs[ResultIndex]->getValueKind(),
           AssocExprs[ResultIndex]->getObjectKind()),
      NumAssocs(AssocExprs.size()), ResultIndex(ResultIndex),
      IsExprPredicate(false), DefaultLoc(DefaultLoc), RParenLoc(RParenLoc) {
  assert(AssocTypes.size() == AssocExprs.size() &&
         "Must have the same number of association expressions"
         " and TypeSourceInfo!");
  assert(ResultIndex < NumAssocs && "ResultIndex is out-of-bounds!");

  GenericSelectionExprBits.GenericLoc = GenericLoc;
  getTrailingObjects<TypeSourceInfo *>()[getIndexOfControllingType()] =
      ControllingType;
  std::copy(AssocExprs.begin(), AssocExprs.end(),
            getTrailingObjects<Stmt *>() + getIndexOfStartOfAssociatedExprs());
  std::copy(AssocTypes.begin(), AssocTypes.end(),
            getTrailingObjects<TypeSourceInfo *>() +
                getIndexOfStartOfAssociatedTypes());

  setDependence(computeDependence(this, ContainsUnexpandedParameterPack));
}

GenericSelectionExpr::GenericSelectionExpr(
    const ASTContext &Context, SourceLocation GenericLoc, Expr *ControllingExpr,
    ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
    SourceLocation DefaultLoc, SourceLocation RParenLoc,
    bool ContainsUnexpandedParameterPack)
    : Expr(GenericSelectionExprClass, Context.DependentTy, VK_PRValue,
           OK_Ordinary),
      NumAssocs(AssocExprs.size()), ResultIndex(ResultDependentIndex),
      IsExprPredicate(true), DefaultLoc(DefaultLoc), RParenLoc(RParenLoc) {
  assert(AssocTypes.size() == AssocExprs.size() &&
         "Must have the same number of association expressions"
         " and TypeSourceInfo!");

  GenericSelectionExprBits.GenericLoc = GenericLoc;
  getTrailingObjects<Stmt *>()[getIndexOfControllingExpression()] =
      ControllingExpr;
  std::copy(AssocExprs.begin(), AssocExprs.end(),
            getTrailingObjects<Stmt *>() + getIndexOfStartOfAssociatedExprs());
  std::copy(AssocTypes.begin(), AssocTypes.end(),
            getTrailingObjects<TypeSourceInfo *>() +
                getIndexOfStartOfAssociatedTypes());

  setDependence(computeDependence(this, ContainsUnexpandedParameterPack));
}

GenericSelectionExpr::GenericSelectionExpr(
    const ASTContext &Context, SourceLocation GenericLoc,
    TypeSourceInfo *ControllingType, ArrayRef<TypeSourceInfo *> AssocTypes,
    ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
    SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack)
    : Expr(GenericSelectionExprClass, Context.DependentTy, VK_PRValue,
           OK_Ordinary),
      NumAssocs(AssocExprs.size()), ResultIndex(ResultDependentIndex),
      IsExprPredicate(false), DefaultLoc(DefaultLoc), RParenLoc(RParenLoc) {
  assert(AssocTypes.size() == AssocExprs.size() &&
         "Must have the same number of association expressions"
         " and TypeSourceInfo!");

  GenericSelectionExprBits.GenericLoc = GenericLoc;
  getTrailingObjects<TypeSourceInfo *>()[getIndexOfControllingType()] =
      ControllingType;
  std::copy(AssocExprs.begin(), AssocExprs.end(),
            getTrailingObjects<Stmt *>() + getIndexOfStartOfAssociatedExprs());
  std::copy(AssocTypes.begin(), AssocTypes.end(),
            getTrailingObjects<TypeSourceInfo *>() +
                getIndexOfStartOfAssociatedTypes());

  setDependence(computeDependence(this, ContainsUnexpandedParameterPack));
}

GenericSelectionExpr::GenericSelectionExpr(EmptyShell Empty, unsigned NumAssocs)
    : Expr(GenericSelectionExprClass, Empty), NumAssocs(NumAssocs) {}

GenericSelectionExpr *GenericSelectionExpr::Create(
    const ASTContext &Context, SourceLocation GenericLoc, Expr *ControllingExpr,
    ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
    SourceLocation DefaultLoc, SourceLocation RParenLoc,
    bool ContainsUnexpandedParameterPack, unsigned ResultIndex) {
  unsigned NumAssocs = AssocExprs.size();
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
      alignof(GenericSelectionExpr));
  return new (Mem) GenericSelectionExpr(
      Context, GenericLoc, ControllingExpr, AssocTypes, AssocExprs, DefaultLoc,
      RParenLoc, ContainsUnexpandedParameterPack, ResultIndex);
}

GenericSelectionExpr *GenericSelectionExpr::Create(
    const ASTContext &Context, SourceLocation GenericLoc, Expr *ControllingExpr,
    ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
    SourceLocation DefaultLoc, SourceLocation RParenLoc,
    bool ContainsUnexpandedParameterPack) {
  unsigned NumAssocs = AssocExprs.size();
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
      alignof(GenericSelectionExpr));
  return new (Mem) GenericSelectionExpr(
      Context, GenericLoc, ControllingExpr, AssocTypes, AssocExprs, DefaultLoc,
      RParenLoc, ContainsUnexpandedParameterPack);
}

GenericSelectionExpr *GenericSelectionExpr::Create(
    const ASTContext &Context, SourceLocation GenericLoc,
    TypeSourceInfo *ControllingType, ArrayRef<TypeSourceInfo *> AssocTypes,
    ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
    SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack,
    unsigned ResultIndex) {
  unsigned NumAssocs = AssocExprs.size();
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
      alignof(GenericSelectionExpr));
  return new (Mem) GenericSelectionExpr(
      Context, GenericLoc, ControllingType, AssocTypes, AssocExprs, DefaultLoc,
      RParenLoc, ContainsUnexpandedParameterPack, ResultIndex);
}

GenericSelectionExpr *GenericSelectionExpr::Create(
    const ASTContext &Context, SourceLocation GenericLoc,
    TypeSourceInfo *ControllingType, ArrayRef<TypeSourceInfo *> AssocTypes,
    ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
    SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack) {
  unsigned NumAssocs = AssocExprs.size();
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
      alignof(GenericSelectionExpr));
  return new (Mem) GenericSelectionExpr(
      Context, GenericLoc, ControllingType, AssocTypes, AssocExprs, DefaultLoc,
      RParenLoc, ContainsUnexpandedParameterPack);
}

GenericSelectionExpr *
GenericSelectionExpr::CreateEmpty(const ASTContext &Context,
                                  unsigned NumAssocs) {
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
      alignof(GenericSelectionExpr));
  return new (Mem) GenericSelectionExpr(EmptyShell(), NumAssocs);
}

//===----------------------------------------------------------------------===//
//  DesignatedInitExpr
//===----------------------------------------------------------------------===//

const IdentifierInfo *DesignatedInitExpr::Designator::getFieldName() const {
  assert(isFieldDesignator() && "Only valid on a field designator");
  if (FieldInfo.NameOrField & 0x01)
    return reinterpret_cast<IdentifierInfo *>(FieldInfo.NameOrField & ~0x01);
  return getFieldDecl()->getIdentifier();
}

DesignatedInitExpr::DesignatedInitExpr(const ASTContext &C, QualType Ty,
                                       llvm::ArrayRef<Designator> Designators,
                                       SourceLocation EqualOrColonLoc,
                                       bool GNUSyntax,
                                       ArrayRef<Expr *> IndexExprs, Expr *Init)
    : Expr(DesignatedInitExprClass, Ty, Init->getValueKind(),
           Init->getObjectKind()),
      EqualOrColonLoc(EqualOrColonLoc), GNUSyntax(GNUSyntax),
      NumDesignators(Designators.size()), NumSubExprs(IndexExprs.size() + 1) {
  this->Designators = new (C) Designator[NumDesignators];

  // Record the initializer itself.
  child_iterator Child = child_begin();
  *Child++ = Init;

  // Copy the designators and their subexpressions, computing
  // value-dependence along the way.
  unsigned IndexIdx = 0;
  for (unsigned I = 0; I != NumDesignators; ++I) {
    this->Designators[I] = Designators[I];
    if (this->Designators[I].isArrayDesignator()) {
      // Copy the index expressions into permanent storage.
      *Child++ = IndexExprs[IndexIdx++];
    } else if (this->Designators[I].isArrayRangeDesignator()) {
      // Copy the start/end expressions into permanent storage.
      *Child++ = IndexExprs[IndexIdx++];
      *Child++ = IndexExprs[IndexIdx++];
    }
  }

  assert(IndexIdx == IndexExprs.size() && "Wrong number of index expressions");
  setDependence(computeDependence(this));
}

DesignatedInitExpr *
DesignatedInitExpr::Create(const ASTContext &C,
                           llvm::ArrayRef<Designator> Designators,
                           ArrayRef<Expr*> IndexExprs,
                           SourceLocation ColonOrEqualLoc,
                           bool UsesColonSyntax, Expr *Init) {
  void *Mem = C.Allocate(totalSizeToAlloc<Stmt *>(IndexExprs.size() + 1),
                         alignof(DesignatedInitExpr));
  return new (Mem) DesignatedInitExpr(C, C.VoidTy, Designators,
                                      ColonOrEqualLoc, UsesColonSyntax,
                                      IndexExprs, Init);
}

DesignatedInitExpr *DesignatedInitExpr::CreateEmpty(const ASTContext &C,
                                                    unsigned NumIndexExprs) {
  void *Mem = C.Allocate(totalSizeToAlloc<Stmt *>(NumIndexExprs + 1),
                         alignof(DesignatedInitExpr));
  return new (Mem) DesignatedInitExpr(NumIndexExprs + 1);
}

void DesignatedInitExpr::setDesignators(const ASTContext &C,
                                        const Designator *Desigs,
                                        unsigned NumDesigs) {
  Designators = new (C) Designator[NumDesigs];
  NumDesignators = NumDesigs;
  for (unsigned I = 0; I != NumDesigs; ++I)
    Designators[I] = Desigs[I];
}

SourceRange DesignatedInitExpr::getDesignatorsSourceRange() const {
  DesignatedInitExpr *DIE = const_cast<DesignatedInitExpr*>(this);
  if (size() == 1)
    return DIE->getDesignator(0)->getSourceRange();
  return SourceRange(DIE->getDesignator(0)->getBeginLoc(),
                     DIE->getDesignator(size() - 1)->getEndLoc());
}

SourceLocation DesignatedInitExpr::getBeginLoc() const {
  auto *DIE = const_cast<DesignatedInitExpr *>(this);
  Designator &First = *DIE->getDesignator(0);
  if (First.isFieldDesignator()) {
    // Skip past implicit designators for anonymous structs/unions, since
    // these do not have valid source locations.
    for (unsigned int i = 0; i < DIE->size(); i++) {
      Designator &Des = *DIE->getDesignator(i);
      SourceLocation retval = GNUSyntax ? Des.getFieldLoc() : Des.getDotLoc();
      if (!retval.isValid())
        continue;
      return retval;
    }
  }
  return First.getLBracketLoc();
}

SourceLocation DesignatedInitExpr::getEndLoc() const {
  return getInit()->getEndLoc();
}

Expr *DesignatedInitExpr::getArrayIndex(const Designator& D) const {
  assert(D.isArrayDesignator() && "Requires array designator");
  return getSubExpr(D.getArrayIndex() + 1);
}

Expr *DesignatedInitExpr::getArrayRangeStart(const Designator &D) const {
  assert(D.isArrayRangeDesignator() && "Requires array range designator");
  return getSubExpr(D.getArrayIndex() + 1);
}

Expr *DesignatedInitExpr::getArrayRangeEnd(const Designator &D) const {
  assert(D.isArrayRangeDesignator() && "Requires array range designator");
  return getSubExpr(D.getArrayIndex() + 2);
}

/// Replaces the designator at index @p Idx with the series
/// of designators in [First, Last).
void DesignatedInitExpr::ExpandDesignator(const ASTContext &C, unsigned Idx,
                                          const Designator *First,
                                          const Designator *Last) {
  unsigned NumNewDesignators = Last - First;
  if (NumNewDesignators == 0) {
    std::copy_backward(Designators + Idx + 1,
                       Designators + NumDesignators,
                       Designators + Idx);
    --NumNewDesignators;
    return;
  }
  if (NumNewDesignators == 1) {
    Designators[Idx] = *First;
    return;
  }

  Designator *NewDesignators
    = new (C) Designator[NumDesignators - 1 + NumNewDesignators];
  std::copy(Designators, Designators + Idx, NewDesignators);
  std::copy(First, Last, NewDesignators + Idx);
  std::copy(Designators + Idx + 1, Designators + NumDesignators,
            NewDesignators + Idx + NumNewDesignators);
  Designators = NewDesignators;
  NumDesignators = NumDesignators - 1 + NumNewDesignators;
}

DesignatedInitUpdateExpr::DesignatedInitUpdateExpr(const ASTContext &C,
                                                   SourceLocation lBraceLoc,
                                                   Expr *baseExpr,
                                                   SourceLocation rBraceLoc)
    : Expr(DesignatedInitUpdateExprClass, baseExpr->getType(), VK_PRValue,
           OK_Ordinary) {
  BaseAndUpdaterExprs[0] = baseExpr;

  InitListExpr *ILE =
      new (C) InitListExpr(C, lBraceLoc, std::nullopt, rBraceLoc);
  ILE->setType(baseExpr->getType());
  BaseAndUpdaterExprs[1] = ILE;

  // FIXME: this is wrong, set it correctly.
  setDependence(ExprDependence::None);
}

SourceLocation DesignatedInitUpdateExpr::getBeginLoc() const {
  return getBase()->getBeginLoc();
}

SourceLocation DesignatedInitUpdateExpr::getEndLoc() const {
  return getBase()->getEndLoc();
}

ParenListExpr::ParenListExpr(SourceLocation LParenLoc, ArrayRef<Expr *> Exprs,
                             SourceLocation RParenLoc)
    : Expr(ParenListExprClass, QualType(), VK_PRValue, OK_Ordinary),
      LParenLoc(LParenLoc), RParenLoc(RParenLoc) {
  ParenListExprBits.NumExprs = Exprs.size();

  for (unsigned I = 0, N = Exprs.size(); I != N; ++I)
    getTrailingObjects<Stmt *>()[I] = Exprs[I];
  setDependence(computeDependence(this));
}

ParenListExpr::ParenListExpr(EmptyShell Empty, unsigned NumExprs)
    : Expr(ParenListExprClass, Empty) {
  ParenListExprBits.NumExprs = NumExprs;
}

ParenListExpr *ParenListExpr::Create(const ASTContext &Ctx,
                                     SourceLocation LParenLoc,
                                     ArrayRef<Expr *> Exprs,
                                     SourceLocation RParenLoc) {
  void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(Exprs.size()),
                           alignof(ParenListExpr));
  return new (Mem) ParenListExpr(LParenLoc, Exprs, RParenLoc);
}

ParenListExpr *ParenListExpr::CreateEmpty(const ASTContext &Ctx,
                                          unsigned NumExprs) {
  void *Mem =
      Ctx.Allocate(totalSizeToAlloc<Stmt *>(NumExprs), alignof(ParenListExpr));
  return new (Mem) ParenListExpr(EmptyShell(), NumExprs);
}

BinaryOperator::BinaryOperator(const ASTContext &Ctx, Expr *lhs, Expr *rhs,
                               Opcode opc, QualType ResTy, ExprValueKind VK,
                               ExprObjectKind OK, SourceLocation opLoc,
                               FPOptionsOverride FPFeatures)
    : Expr(BinaryOperatorClass, ResTy, VK, OK) {
  BinaryOperatorBits.Opc = opc;
  assert(!isCompoundAssignmentOp() &&
         "Use CompoundAssignOperator for compound assignments");
  BinaryOperatorBits.OpLoc = opLoc;
  SubExprs[LHS] = lhs;
  SubExprs[RHS] = rhs;
  BinaryOperatorBits.HasFPFeatures = FPFeatures.requiresTrailingStorage();
  if (hasStoredFPFeatures())
    setStoredFPFeatures(FPFeatures);
  setDependence(computeDependence(this));
}

BinaryOperator::BinaryOperator(const ASTContext &Ctx, Expr *lhs, Expr *rhs,
                               Opcode opc, QualType ResTy, ExprValueKind VK,
                               ExprObjectKind OK, SourceLocation opLoc,
                               FPOptionsOverride FPFeatures, bool dead2)
    : Expr(CompoundAssignOperatorClass, ResTy, VK, OK) {
  BinaryOperatorBits.Opc = opc;
  assert(isCompoundAssignmentOp() &&
         "Use CompoundAssignOperator for compound assignments");
  BinaryOperatorBits.OpLoc = opLoc;
  SubExprs[LHS] = lhs;
  SubExprs[RHS] = rhs;
  BinaryOperatorBits.HasFPFeatures = FPFeatures.requiresTrailingStorage();
  if (hasStoredFPFeatures())
    setStoredFPFeatures(FPFeatures);
  setDependence(computeDependence(this));
}

BinaryOperator *BinaryOperator::CreateEmpty(const ASTContext &C,
                                            bool HasFPFeatures) {
  unsigned Extra = sizeOfTrailingObjects(HasFPFeatures);
  void *Mem =
      C.Allocate(sizeof(BinaryOperator) + Extra, alignof(BinaryOperator));
  return new (Mem) BinaryOperator(EmptyShell());
}

BinaryOperator *BinaryOperator::Create(const ASTContext &C, Expr *lhs,
                                       Expr *rhs, Opcode opc, QualType ResTy,
                                       ExprValueKind VK, ExprObjectKind OK,
                                       SourceLocation opLoc,
                                       FPOptionsOverride FPFeatures) {
  bool HasFPFeatures = FPFeatures.requiresTrailingStorage();
  unsigned Extra = sizeOfTrailingObjects(HasFPFeatures);
  void *Mem =
      C.Allocate(sizeof(BinaryOperator) + Extra, alignof(BinaryOperator));
  return new (Mem)
      BinaryOperator(C, lhs, rhs, opc, ResTy, VK, OK, opLoc, FPFeatures);
}

CompoundAssignOperator *
CompoundAssignOperator::CreateEmpty(const ASTContext &C, bool HasFPFeatures) {
  unsigned Extra = sizeOfTrailingObjects(HasFPFeatures);
  void *Mem = C.Allocate(sizeof(CompoundAssignOperator) + Extra,
                         alignof(CompoundAssignOperator));
  return new (Mem) CompoundAssignOperator(C, EmptyShell(), HasFPFeatures);
}

CompoundAssignOperator *
CompoundAssignOperator::Create(const ASTContext &C, Expr *lhs, Expr *rhs,
                               Opcode opc, QualType ResTy, ExprValueKind VK,
                               ExprObjectKind OK, SourceLocation opLoc,
                               FPOptionsOverride FPFeatures,
                               QualType CompLHSType, QualType CompResultType) {
  bool HasFPFeatures = FPFeatures.requiresTrailingStorage();
  unsigned Extra = sizeOfTrailingObjects(HasFPFeatures);
  void *Mem = C.Allocate(sizeof(CompoundAssignOperator) + Extra,
                         alignof(CompoundAssignOperator));
  return new (Mem)
      CompoundAssignOperator(C, lhs, rhs, opc, ResTy, VK, OK, opLoc, FPFeatures,
                             CompLHSType, CompResultType);
}

UnaryOperator *UnaryOperator::CreateEmpty(const ASTContext &C,
                                          bool hasFPFeatures) {
  void *Mem = C.Allocate(totalSizeToAlloc<FPOptionsOverride>(hasFPFeatures),
                         alignof(UnaryOperator));
  return new (Mem) UnaryOperator(hasFPFeatures, EmptyShell());
}

UnaryOperator::UnaryOperator(const ASTContext &Ctx, Expr *input, Opcode opc,
                             QualType type, ExprValueKind VK, ExprObjectKind OK,
                             SourceLocation l, bool CanOverflow,
                             FPOptionsOverride FPFeatures)
    : Expr(UnaryOperatorClass, type, VK, OK), Val(input) {
  UnaryOperatorBits.Opc = opc;
  UnaryOperatorBits.CanOverflow = CanOverflow;
  UnaryOperatorBits.Loc = l;
  UnaryOperatorBits.HasFPFeatures = FPFeatures.requiresTrailingStorage();
  if (hasStoredFPFeatures())
    setStoredFPFeatures(FPFeatures);
  setDependence(computeDependence(this, Ctx));
}

UnaryOperator *UnaryOperator::Create(const ASTContext &C, Expr *input,
                                     Opcode opc, QualType type,
                                     ExprValueKind VK, ExprObjectKind OK,
                                     SourceLocation l, bool CanOverflow,
                                     FPOptionsOverride FPFeatures) {
  bool HasFPFeatures = FPFeatures.requiresTrailingStorage();
  unsigned Size = totalSizeToAlloc<FPOptionsOverride>(HasFPFeatures);
  void *Mem = C.Allocate(Size, alignof(UnaryOperator));
  return new (Mem)
      UnaryOperator(C, input, opc, type, VK, OK, l, CanOverflow, FPFeatures);
}

const OpaqueValueExpr *OpaqueValueExpr::findInCopyConstruct(const Expr *e) {
  if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(e))
    e = ewc->getSubExpr();
  if (const MaterializeTemporaryExpr *m = dyn_cast<MaterializeTemporaryExpr>(e))
    e = m->getSubExpr();
  e = cast<CXXConstructExpr>(e)->getArg(0);
  while (const ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(e))
    e = ice->getSubExpr();
  return cast<OpaqueValueExpr>(e);
}

PseudoObjectExpr *PseudoObjectExpr::Create(const ASTContext &Context,
                                           EmptyShell sh,
                                           unsigned numSemanticExprs) {
  void *buffer =
      Context.Allocate(totalSizeToAlloc<Expr *>(1 + numSemanticExprs),
                       alignof(PseudoObjectExpr));
  return new(buffer) PseudoObjectExpr(sh, numSemanticExprs);
}

PseudoObjectExpr::PseudoObjectExpr(EmptyShell shell, unsigned numSemanticExprs)
  : Expr(PseudoObjectExprClass, shell) {
  PseudoObjectExprBits.NumSubExprs = numSemanticExprs + 1;
}

PseudoObjectExpr *PseudoObjectExpr::Create(const ASTContext &C, Expr *syntax,
                                           ArrayRef<Expr*> semantics,
                                           unsigned resultIndex) {
  assert(syntax && "no syntactic expression!");
  assert(semantics.size() && "no semantic expressions!");

  QualType type;
  ExprValueKind VK;
  if (resultIndex == NoResult) {
    type = C.VoidTy;
    VK = VK_PRValue;
  } else {
    assert(resultIndex < semantics.size());
    type = semantics[resultIndex]->getType();
    VK = semantics[resultIndex]->getValueKind();
    assert(semantics[resultIndex]->getObjectKind() == OK_Ordinary);
  }

  void *buffer = C.Allocate(totalSizeToAlloc<Expr *>(semantics.size() + 1),
                            alignof(PseudoObjectExpr));
  return new(buffer) PseudoObjectExpr(type, VK, syntax, semantics,
                                      resultIndex);
}

PseudoObjectExpr::PseudoObjectExpr(QualType type, ExprValueKind VK,
                                   Expr *syntax, ArrayRef<Expr *> semantics,
                                   unsigned resultIndex)
    : Expr(PseudoObjectExprClass, type, VK, OK_Ordinary) {
  PseudoObjectExprBits.NumSubExprs = semantics.size() + 1;
  PseudoObjectExprBits.ResultIndex = resultIndex + 1;

  for (unsigned i = 0, e = semantics.size() + 1; i != e; ++i) {
    Expr *E = (i == 0 ? syntax : semantics[i-1]);
    getSubExprsBuffer()[i] = E;

    if (isa<OpaqueValueExpr>(E))
      assert(cast<OpaqueValueExpr>(E)->getSourceExpr() != nullptr &&
             "opaque-value semantic expressions for pseudo-object "
             "operations must have sources");
  }

  setDependence(computeDependence(this));
}

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

// UnaryExprOrTypeTraitExpr
Stmt::child_range UnaryExprOrTypeTraitExpr::children() {
  const_child_range CCR =
      const_cast<const UnaryExprOrTypeTraitExpr *>(this)->children();
  return child_range(cast_away_const(CCR.begin()), cast_away_const(CCR.end()));
}

Stmt::const_child_range UnaryExprOrTypeTraitExpr::children() const {
  // If this is of a type and the type is a VLA type (and not a typedef), the
  // size expression of the VLA needs to be treated as an executable expression.
  // Why isn't this weirdness documented better in StmtIterator?
  if (isArgumentType()) {
    if (const VariableArrayType *T =
            dyn_cast<VariableArrayType>(getArgumentType().getTypePtr()))
      return const_child_range(const_child_iterator(T), const_child_iterator());
    return const_child_range(const_child_iterator(), const_child_iterator());
  }
  return const_child_range(&Argument.Ex, &Argument.Ex + 1);
}

AtomicExpr::AtomicExpr(SourceLocation BLoc, ArrayRef<Expr *> args, QualType t,
                       AtomicOp op, SourceLocation RP)
    : Expr(AtomicExprClass, t, VK_PRValue, OK_Ordinary),
      NumSubExprs(args.size()), BuiltinLoc(BLoc), RParenLoc(RP), Op(op) {
  assert(args.size() == getNumSubExprs(op) && "wrong number of subexpressions");
  for (unsigned i = 0; i != args.size(); i++)
    SubExprs[i] = args[i];
  setDependence(computeDependence(this));
}

unsigned AtomicExpr::getNumSubExprs(AtomicOp Op) {
  switch (Op) {
  case AO__c11_atomic_init:
  case AO__opencl_atomic_init:
  case AO__c11_atomic_load:
  case AO__atomic_load_n:
    return 2;

  case AO__scoped_atomic_load_n:
  case AO__opencl_atomic_load:
  case AO__hip_atomic_load:
  case AO__c11_atomic_store:
  case AO__c11_atomic_exchange:
  case AO__atomic_load:
  case AO__atomic_store:
  case AO__atomic_store_n:
  case AO__atomic_exchange_n:
  case AO__c11_atomic_fetch_add:
  case AO__c11_atomic_fetch_sub:
  case AO__c11_atomic_fetch_and:
  case AO__c11_atomic_fetch_or:
  case AO__c11_atomic_fetch_xor:
  case AO__c11_atomic_fetch_nand:
  case AO__c11_atomic_fetch_max:
  case AO__c11_atomic_fetch_min:
  case AO__atomic_fetch_add:
  case AO__atomic_fetch_sub:
  case AO__atomic_fetch_and:
  case AO__atomic_fetch_or:
  case AO__atomic_fetch_xor:
  case AO__atomic_fetch_nand:
  case AO__atomic_add_fetch:
  case AO__atomic_sub_fetch:
  case AO__atomic_and_fetch:
  case AO__atomic_or_fetch:
  case AO__atomic_xor_fetch:
  case AO__atomic_nand_fetch:
  case AO__atomic_min_fetch:
  case AO__atomic_max_fetch:
  case AO__atomic_fetch_min:
  case AO__atomic_fetch_max:
    return 3;

  case AO__scoped_atomic_load:
  case AO__scoped_atomic_store:
  case AO__scoped_atomic_store_n:
  case AO__scoped_atomic_fetch_add:
  case AO__scoped_atomic_fetch_sub:
  case AO__scoped_atomic_fetch_and:
  case AO__scoped_atomic_fetch_or:
  case AO__scoped_atomic_fetch_xor:
  case AO__scoped_atomic_fetch_nand:
  case AO__scoped_atomic_add_fetch:
  case AO__scoped_atomic_sub_fetch:
  case AO__scoped_atomic_and_fetch:
  case AO__scoped_atomic_or_fetch:
  case AO__scoped_atomic_xor_fetch:
  case AO__scoped_atomic_nand_fetch:
  case AO__scoped_atomic_min_fetch:
  case AO__scoped_atomic_max_fetch:
  case AO__scoped_atomic_fetch_min:
  case AO__scoped_atomic_fetch_max:
  case AO__scoped_atomic_exchange_n:
  case AO__hip_atomic_exchange:
  case AO__hip_atomic_fetch_add:
  case AO__hip_atomic_fetch_sub:
  case AO__hip_atomic_fetch_and:
  case AO__hip_atomic_fetch_or:
  case AO__hip_atomic_fetch_xor:
  case AO__hip_atomic_fetch_min:
  case AO__hip_atomic_fetch_max:
  case AO__opencl_atomic_store:
  case AO__hip_atomic_store:
  case AO__opencl_atomic_exchange:
  case AO__opencl_atomic_fetch_add:
  case AO__opencl_atomic_fetch_sub:
  case AO__opencl_atomic_fetch_and:
  case AO__opencl_atomic_fetch_or:
  case AO__opencl_atomic_fetch_xor:
  case AO__opencl_atomic_fetch_min:
  case AO__opencl_atomic_fetch_max:
  case AO__atomic_exchange:
    return 4;

  case AO__scoped_atomic_exchange:
  case AO__c11_atomic_compare_exchange_strong:
  case AO__c11_atomic_compare_exchange_weak:
    return 5;
  case AO__hip_atomic_compare_exchange_strong:
  case AO__opencl_atomic_compare_exchange_strong:
  case AO__opencl_atomic_compare_exchange_weak:
  case AO__hip_atomic_compare_exchange_weak:
  case AO__atomic_compare_exchange:
  case AO__atomic_compare_exchange_n:
    return 6;

  case AO__scoped_atomic_compare_exchange:
  case AO__scoped_atomic_compare_exchange_n:
    return 7;
  }
  llvm_unreachable("unknown atomic op");
}

QualType AtomicExpr::getValueType() const {
  auto T = getPtr()->getType()->castAs<PointerType>()->getPointeeType();
  if (auto AT = T->getAs<AtomicType>())
    return AT->getValueType();
  return T;
}

QualType ArraySectionExpr::getBaseOriginalType(const Expr *Base) {
  unsigned ArraySectionCount = 0;
  while (auto *OASE = dyn_cast<ArraySectionExpr>(Base->IgnoreParens())) {
    Base = OASE->getBase();
    ++ArraySectionCount;
  }
  while (auto *ASE =
             dyn_cast<ArraySubscriptExpr>(Base->IgnoreParenImpCasts())) {
    Base = ASE->getBase();
    ++ArraySectionCount;
  }
  Base = Base->IgnoreParenImpCasts();
  auto OriginalTy = Base->getType();
  if (auto *DRE = dyn_cast<DeclRefExpr>(Base))
    if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl()))
      OriginalTy = PVD->getOriginalType().getNonReferenceType();

  for (unsigned Cnt = 0; Cnt < ArraySectionCount; ++Cnt) {
    if (OriginalTy->isAnyPointerType())
      OriginalTy = OriginalTy->getPointeeType();
    else if (OriginalTy->isArrayType())
      OriginalTy = OriginalTy->castAsArrayTypeUnsafe()->getElementType();
    else
      return {};
  }
  return OriginalTy;
}

RecoveryExpr::RecoveryExpr(ASTContext &Ctx, QualType T, SourceLocation BeginLoc,
                           SourceLocation EndLoc, ArrayRef<Expr *> SubExprs)
    : Expr(RecoveryExprClass, T.getNonReferenceType(),
           T->isDependentType() ? VK_LValue : getValueKindForType(T),
           OK_Ordinary),
      BeginLoc(BeginLoc), EndLoc(EndLoc), NumExprs(SubExprs.size()) {
  assert(!T.isNull());
  assert(!llvm::is_contained(SubExprs, nullptr));

  llvm::copy(SubExprs, getTrailingObjects<Expr *>());
  setDependence(computeDependence(this));
}

RecoveryExpr *RecoveryExpr::Create(ASTContext &Ctx, QualType T,
                                   SourceLocation BeginLoc,
                                   SourceLocation EndLoc,
                                   ArrayRef<Expr *> SubExprs) {
  void *Mem = Ctx.Allocate(totalSizeToAlloc<Expr *>(SubExprs.size()),
                           alignof(RecoveryExpr));
  return new (Mem) RecoveryExpr(Ctx, T, BeginLoc, EndLoc, SubExprs);
}

RecoveryExpr *RecoveryExpr::CreateEmpty(ASTContext &Ctx, unsigned NumSubExprs) {
  void *Mem = Ctx.Allocate(totalSizeToAlloc<Expr *>(NumSubExprs),
                           alignof(RecoveryExpr));
  return new (Mem) RecoveryExpr(EmptyShell(), NumSubExprs);
}

void OMPArrayShapingExpr::setDimensions(ArrayRef<Expr *> Dims) {
  assert(
      NumDims == Dims.size() &&
      "Preallocated number of dimensions is different from the provided one.");
  llvm::copy(Dims, getTrailingObjects<Expr *>());
}

void OMPArrayShapingExpr::setBracketsRanges(ArrayRef<SourceRange> BR) {
  assert(
      NumDims == BR.size() &&
      "Preallocated number of dimensions is different from the provided one.");
  llvm::copy(BR, getTrailingObjects<SourceRange>());
}

OMPArrayShapingExpr::OMPArrayShapingExpr(QualType ExprTy, Expr *Op,
                                         SourceLocation L, SourceLocation R,
                                         ArrayRef<Expr *> Dims)
    : Expr(OMPArrayShapingExprClass, ExprTy, VK_LValue, OK_Ordinary), LPLoc(L),
      RPLoc(R), NumDims(Dims.size()) {
  setBase(Op);
  setDimensions(Dims);
  setDependence(computeDependence(this));
}

OMPArrayShapingExpr *
OMPArrayShapingExpr::Create(const ASTContext &Context, QualType T, Expr *Op,
                            SourceLocation L, SourceLocation R,
                            ArrayRef<Expr *> Dims,
                            ArrayRef<SourceRange> BracketRanges) {
  assert(Dims.size() == BracketRanges.size() &&
         "Different number of dimensions and brackets ranges.");
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Expr *, SourceRange>(Dims.size() + 1, Dims.size()),
      alignof(OMPArrayShapingExpr));
  auto *E = new (Mem) OMPArrayShapingExpr(T, Op, L, R, Dims);
  E->setBracketsRanges(BracketRanges);
  return E;
}

OMPArrayShapingExpr *OMPArrayShapingExpr::CreateEmpty(const ASTContext &Context,
                                                      unsigned NumDims) {
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Expr *, SourceRange>(NumDims + 1, NumDims),
      alignof(OMPArrayShapingExpr));
  return new (Mem) OMPArrayShapingExpr(EmptyShell(), NumDims);
}

void OMPIteratorExpr::setIteratorDeclaration(unsigned I, Decl *D) {
  assert(I < NumIterators &&
         "Idx is greater or equal the number of iterators definitions.");
  getTrailingObjects<Decl *>()[I] = D;
}

void OMPIteratorExpr::setAssignmentLoc(unsigned I, SourceLocation Loc) {
  assert(I < NumIterators &&
         "Idx is greater or equal the number of iterators definitions.");
  getTrailingObjects<
      SourceLocation>()[I * static_cast<int>(RangeLocOffset::Total) +
                        static_cast<int>(RangeLocOffset::AssignLoc)] = Loc;
}

void OMPIteratorExpr::setIteratorRange(unsigned I, Expr *Begin,
                                       SourceLocation ColonLoc, Expr *End,
                                       SourceLocation SecondColonLoc,
                                       Expr *Step) {
  assert(I < NumIterators &&
         "Idx is greater or equal the number of iterators definitions.");
  getTrailingObjects<Expr *>()[I * static_cast<int>(RangeExprOffset::Total) +
                               static_cast<int>(RangeExprOffset::Begin)] =
      Begin;
  getTrailingObjects<Expr *>()[I * static_cast<int>(RangeExprOffset::Total) +
                               static_cast<int>(RangeExprOffset::End)] = End;
  getTrailingObjects<Expr *>()[I * static_cast<int>(RangeExprOffset::Total) +
                               static_cast<int>(RangeExprOffset::Step)] = Step;
  getTrailingObjects<
      SourceLocation>()[I * static_cast<int>(RangeLocOffset::Total) +
                        static_cast<int>(RangeLocOffset::FirstColonLoc)] =
      ColonLoc;
  getTrailingObjects<
      SourceLocation>()[I * static_cast<int>(RangeLocOffset::Total) +
                        static_cast<int>(RangeLocOffset::SecondColonLoc)] =
      SecondColonLoc;
}

Decl *OMPIteratorExpr::getIteratorDecl(unsigned I) {
  return getTrailingObjects<Decl *>()[I];
}

OMPIteratorExpr::IteratorRange OMPIteratorExpr::getIteratorRange(unsigned I) {
  IteratorRange Res;
  Res.Begin =
      getTrailingObjects<Expr *>()[I * static_cast<int>(
                                           RangeExprOffset::Total) +
                                   static_cast<int>(RangeExprOffset::Begin)];
  Res.End =
      getTrailingObjects<Expr *>()[I * static_cast<int>(
                                           RangeExprOffset::Total) +
                                   static_cast<int>(RangeExprOffset::End)];
  Res.Step =
      getTrailingObjects<Expr *>()[I * static_cast<int>(
                                           RangeExprOffset::Total) +
                                   static_cast<int>(RangeExprOffset::Step)];
  return Res;
}

SourceLocation OMPIteratorExpr::getAssignLoc(unsigned I) const {
  return getTrailingObjects<
      SourceLocation>()[I * static_cast<int>(RangeLocOffset::Total) +
                        static_cast<int>(RangeLocOffset::AssignLoc)];
}

SourceLocation OMPIteratorExpr::getColonLoc(unsigned I) const {
  return getTrailingObjects<
      SourceLocation>()[I * static_cast<int>(RangeLocOffset::Total) +
                        static_cast<int>(RangeLocOffset::FirstColonLoc)];
}

SourceLocation OMPIteratorExpr::getSecondColonLoc(unsigned I) const {
  return getTrailingObjects<
      SourceLocation>()[I * static_cast<int>(RangeLocOffset::Total) +
                        static_cast<int>(RangeLocOffset::SecondColonLoc)];
}

void OMPIteratorExpr::setHelper(unsigned I, const OMPIteratorHelperData &D) {
  getTrailingObjects<OMPIteratorHelperData>()[I] = D;
}

OMPIteratorHelperData &OMPIteratorExpr::getHelper(unsigned I) {
  return getTrailingObjects<OMPIteratorHelperData>()[I];
}

const OMPIteratorHelperData &OMPIteratorExpr::getHelper(unsigned I) const {
  return getTrailingObjects<OMPIteratorHelperData>()[I];
}

OMPIteratorExpr::OMPIteratorExpr(
    QualType ExprTy, SourceLocation IteratorKwLoc, SourceLocation L,
    SourceLocation R, ArrayRef<OMPIteratorExpr::IteratorDefinition> Data,
    ArrayRef<OMPIteratorHelperData> Helpers)
    : Expr(OMPIteratorExprClass, ExprTy, VK_LValue, OK_Ordinary),
      IteratorKwLoc(IteratorKwLoc), LPLoc(L), RPLoc(R),
      NumIterators(Data.size()) {
  for (unsigned I = 0, E = Data.size(); I < E; ++I) {
    const IteratorDefinition &D = Data[I];
    setIteratorDeclaration(I, D.IteratorDecl);
    setAssignmentLoc(I, D.AssignmentLoc);
    setIteratorRange(I, D.Range.Begin, D.ColonLoc, D.Range.End,
                     D.SecondColonLoc, D.Range.Step);
    setHelper(I, Helpers[I]);
  }
  setDependence(computeDependence(this));
}

OMPIteratorExpr *
OMPIteratorExpr::Create(const ASTContext &Context, QualType T,
                        SourceLocation IteratorKwLoc, SourceLocation L,
                        SourceLocation R,
                        ArrayRef<OMPIteratorExpr::IteratorDefinition> Data,
                        ArrayRef<OMPIteratorHelperData> Helpers) {
  assert(Data.size() == Helpers.size() &&
         "Data and helpers must have the same size.");
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Decl *, Expr *, SourceLocation, OMPIteratorHelperData>(
          Data.size(), Data.size() * static_cast<int>(RangeExprOffset::Total),
          Data.size() * static_cast<int>(RangeLocOffset::Total),
          Helpers.size()),
      alignof(OMPIteratorExpr));
  return new (Mem) OMPIteratorExpr(T, IteratorKwLoc, L, R, Data, Helpers);
}

OMPIteratorExpr *OMPIteratorExpr::CreateEmpty(const ASTContext &Context,
                                              unsigned NumIterators) {
  void *Mem = Context.Allocate(
      totalSizeToAlloc<Decl *, Expr *, SourceLocation, OMPIteratorHelperData>(
          NumIterators, NumIterators * static_cast<int>(RangeExprOffset::Total),
          NumIterators * static_cast<int>(RangeLocOffset::Total), NumIterators),
      alignof(OMPIteratorExpr));
  return new (Mem) OMPIteratorExpr(EmptyShell(), NumIterators);
}