//===-- ODRHash.cpp - Hashing to diagnose ODR failures ----------*- C++ -*-===//

//

// 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

//

//===----------------------------------------------------------------------===//

///

/// \file

/// This file implements the ODRHash class, which calculates a hash based

/// on AST nodes, which is stable across different runs.

///

//===----------------------------------------------------------------------===//

#include "clang/AST/ODRHash.h"

#include "clang/AST/DeclVisitor.h"

#include "clang/AST/NestedNameSpecifier.h"

#include "clang/AST/StmtVisitor.h"

#include "clang/AST/TypeVisitor.h"

using namespace clang;

void ODRHash::AddStmt(const Stmt *S) {

  assert(S && "Expecting non-null pointer.");

  S->ProcessODRHash(ID, *this);

}

void ODRHash::AddIdentifierInfo(const IdentifierInfo *II) {

  assert(II && "Expecting non-null pointer.");

  ID.AddString(II->getName());

}

void ODRHash::AddDeclarationName(DeclarationName Name, bool TreatAsDecl) {

  if (TreatAsDecl)

    // Matches the NamedDecl check in AddDecl

    AddBoolean(true);

  AddDeclarationNameImpl(Name);

  if (TreatAsDecl)

    // Matches the ClassTemplateSpecializationDecl check in AddDecl

    AddBoolean(false);

}

void ODRHash::AddDeclarationNameImpl(DeclarationName Name) {

  // Index all DeclarationName and use index numbers to refer to them.

  auto Result = DeclNameMap.insert(std::make_pair(Name, DeclNameMap.size()));

  ID.AddInteger(Result.first->second);

  if (!Result.second) {

    // If found in map, the DeclarationName has previously been processed.

    return;

  }

  // First time processing each DeclarationName, also process its details.

  AddBoolean(Name.isEmpty());

  if (Name.isEmpty())

    return;

  auto Kind = Name.getNameKind();

  ID.AddInteger(Kind);

  switch (Kind) {

  case DeclarationName::Identifier:

    AddIdentifierInfo(Name.getAsIdentifierInfo());

    break;

  case DeclarationName::ObjCZeroArgSelector:

  case DeclarationName::ObjCOneArgSelector:

  case DeclarationName::ObjCMultiArgSelector: {

    Selector S = Name.getObjCSelector();

    AddBoolean(S.isNull());

    AddBoolean(S.isKeywordSelector());

    AddBoolean(S.isUnarySelector());

    unsigned NumArgs = S.getNumArgs();

    ID.AddInteger(NumArgs);

    for (unsigned i = 0; i < NumArgs; 
++i23
) {

      const IdentifierInfo *II = S.getIdentifierInfoForSlot(i);

      AddBoolean(II);

      if (II) {

        AddIdentifierInfo(II);

      }

    }

    break;

  }

  case DeclarationName::CXXConstructorName:

  case DeclarationName::CXXDestructorName:

    AddQualType(Name.getCXXNameType());

    break;

  case DeclarationName::CXXOperatorName:

    ID.AddInteger(Name.getCXXOverloadedOperator());

    break;

  case DeclarationName::CXXLiteralOperatorName:

    AddIdentifierInfo(Name.getCXXLiteralIdentifier());

    break;

  case DeclarationName::CXXConversionFunctionName:

    AddQualType(Name.getCXXNameType());

    break;

  case DeclarationName::CXXUsingDirective:

    break;

  case DeclarationName::CXXDeductionGuideName: {

    auto *Template = Name.getCXXDeductionGuideTemplate();

    AddBoolean(Template);

    if (Template) {

      AddDecl(Template);

    }

  }

  }

}

void ODRHash::AddNestedNameSpecifier(const NestedNameSpecifier *NNS) {

  assert(NNS && "Expecting non-null pointer.");

  const auto *Prefix = NNS->getPrefix();

  AddBoolean(Prefix);

  if (Prefix) {

    AddNestedNameSpecifier(Prefix);

  }

  auto Kind = NNS->getKind();

  ID.AddInteger(Kind);

  switch (Kind) {

  case NestedNameSpecifier::Identifier:

    AddIdentifierInfo(NNS->getAsIdentifier());

    break;

  case NestedNameSpecifier::Namespace:

    AddDecl(NNS->getAsNamespace());

    break;

  case NestedNameSpecifier::NamespaceAlias:

    AddDecl(NNS->getAsNamespaceAlias());

    break;

  case NestedNameSpecifier::TypeSpec:

  case NestedNameSpecifier::TypeSpecWithTemplate:

    AddType(NNS->getAsType());

    break;

  case NestedNameSpecifier::Global:

  case NestedNameSpecifier::Super:

    break;

  }

}

void ODRHash::AddTemplateName(TemplateName Name) {

  auto Kind = Name.getKind();

  ID.AddInteger(Kind);

  switch (Kind) {

  case TemplateName::Template:

    AddDecl(Name.getAsTemplateDecl());

    break;

  // TODO: Support these cases.

  case TemplateName::OverloadedTemplate:

  case TemplateName::AssumedTemplate:

  case TemplateName::QualifiedTemplate:

  case TemplateName::DependentTemplate:

  case TemplateName::SubstTemplateTemplateParm:

  case TemplateName::SubstTemplateTemplateParmPack:

  case TemplateName::UsingTemplate:

    break;

  }

}

void ODRHash::AddTemplateArgument(TemplateArgument TA) {

  const auto Kind = TA.getKind();

  ID.AddInteger(Kind);

  switch (Kind) {

    case TemplateArgument::Null:

      llvm_unreachable("Expected valid TemplateArgument");

    case TemplateArgument::Type:

      AddQualType(TA.getAsType());

      break;

    case TemplateArgument::Declaration:

      AddDecl(TA.getAsDecl());

      break;

    case TemplateArgument::NullPtr:

    case TemplateArgument::Integral:

      break;

    case TemplateArgument::Template:

    case TemplateArgument::TemplateExpansion:

      AddTemplateName(TA.getAsTemplateOrTemplatePattern());

      break;

    case TemplateArgument::Expression:

      AddStmt(TA.getAsExpr());

      break;

    case TemplateArgument::Pack:

      ID.AddInteger(TA.pack_size());

      for (auto SubTA : TA.pack_elements()) {

        AddTemplateArgument(SubTA);

      }

      break;

  }

}

void ODRHash::AddTemplateParameterList(const TemplateParameterList *TPL) {

  assert(TPL && "Expecting non-null pointer.");

  ID.AddInteger(TPL->size());

  for (auto *ND : TPL->asArray()) {

    AddSubDecl(ND);

  }

}

void ODRHash::clear() {

  DeclNameMap.clear();

  Bools.clear();

  ID.clear();

}

unsigned ODRHash::CalculateHash() {

  // Append the bools to the end of the data segment backwards.  This allows

  // for the bools data to be compressed 32 times smaller compared to using

  // ID.AddBoolean

  const unsigned unsigned_bits = sizeof(unsigned) * CHAR_BIT;

  const unsigned size = Bools.size();

  const unsigned remainder = size % unsigned_bits;

  const unsigned loops = size / unsigned_bits;

  auto I = Bools.rbegin();

  unsigned value = 0;

  for (unsigned i = 0; i < remainder; 
++i7.10M
) {

    value <<= 1;

    value |= *I;

    ++I;

  }

  ID.AddInteger(value);

  for (unsigned i = 0; i < loops; 
++i546k
) {

    value = 0;

    for (unsigned j = 0; j < unsigned_bits; 
++j17.4M
) {

      value <<= 1;

      value |= *I;

      ++I;

    }

    ID.AddInteger(value);

  }

  assert(I == Bools.rend());

  Bools.clear();

  return ID.ComputeHash();

}

namespace {

// Process a Decl pointer.  Add* methods call back into ODRHash while Visit*

// methods process the relevant parts of the Decl.

class ODRDeclVisitor : public ConstDeclVisitor<ODRDeclVisitor> {

  typedef ConstDeclVisitor<ODRDeclVisitor> Inherited;

  llvm::FoldingSetNodeID &ID;

  ODRHash &Hash;

public:

  ODRDeclVisitor(llvm::FoldingSetNodeID &ID, ODRHash &Hash)

      : ID(ID), Hash(Hash) {}

  void AddStmt(const Stmt *S) {

    Hash.AddBoolean(S);

    if (S) {

      Hash.AddStmt(S);

    }

  }

  void AddIdentifierInfo(const IdentifierInfo *II) {

    Hash.AddBoolean(II);

    if (II) {

      Hash.AddIdentifierInfo(II);

    }

  }

  void AddQualType(QualType T) {

    Hash.AddQualType(T);

  }

  void AddDecl(const Decl *D) {

    Hash.AddBoolean(D);

    if (D) {

      Hash.AddDecl(D);

    }

  }

  void AddTemplateArgument(TemplateArgument TA) {

    Hash.AddTemplateArgument(TA);

  }

  void Visit(const Decl *D) {

    ID.AddInteger(D->getKind());

    Inherited::Visit(D);

  }

  void VisitNamedDecl(const NamedDecl *D) {

    Hash.AddDeclarationName(D->getDeclName());

    Inherited::VisitNamedDecl(D);

  }

  void VisitValueDecl(const ValueDecl *D) {

    if (!isa<FunctionDecl>(D)) {

      AddQualType(D->getType());

    }

    Inherited::VisitValueDecl(D);

  }

  void VisitVarDecl(const VarDecl *D) {

    Hash.AddBoolean(D->isStaticLocal());

    Hash.AddBoolean(D->isConstexpr());

    const bool HasInit = D->hasInit();

    Hash.AddBoolean(HasInit);

    if (HasInit) {

      AddStmt(D->getInit());

    }

    Inherited::VisitVarDecl(D);

  }

  void VisitParmVarDecl(const ParmVarDecl *D) {

    // TODO: Handle default arguments.

    Inherited::VisitParmVarDecl(D);

  }

  void VisitAccessSpecDecl(const AccessSpecDecl *D) {

    ID.AddInteger(D->getAccess());

    Inherited::VisitAccessSpecDecl(D);

  }

  void VisitStaticAssertDecl(const StaticAssertDecl *D) {

    AddStmt(D->getAssertExpr());

    AddStmt(D->getMessage());

    Inherited::VisitStaticAssertDecl(D);

  }

  void VisitFieldDecl(const FieldDecl *D) {

    const bool IsBitfield = D->isBitField();

    Hash.AddBoolean(IsBitfield);

    if (IsBitfield) {

      AddStmt(D->getBitWidth());

    }

    Hash.AddBoolean(D->isMutable());

    AddStmt(D->getInClassInitializer());

    Inherited::VisitFieldDecl(D);

  }

  void VisitFunctionDecl(const FunctionDecl *D) {

    // Handled by the ODRHash for FunctionDecl

    ID.AddInteger(D->getODRHash());

    Inherited::VisitFunctionDecl(D);

  }

  void VisitCXXMethodDecl(const CXXMethodDecl *D) {

    // Handled by the ODRHash for FunctionDecl

    Inherited::VisitCXXMethodDecl(D);

  }

  void VisitTypedefNameDecl(const TypedefNameDecl *D) {

    AddQualType(D->getUnderlyingType());

    Inherited::VisitTypedefNameDecl(D);

  }

  void VisitTypedefDecl(const TypedefDecl *D) {

    Inherited::VisitTypedefDecl(D);

  }

  void VisitTypeAliasDecl(const TypeAliasDecl *D) {

    Inherited::VisitTypeAliasDecl(D);

  }

  void VisitFriendDecl(const FriendDecl *D) {

    TypeSourceInfo *TSI = D->getFriendType();

    Hash.AddBoolean(TSI);

    if (TSI) {

      AddQualType(TSI->getType());

    } else {

      AddDecl(D->getFriendDecl());

    }

  }

  void VisitTemplateTypeParmDecl(const TemplateTypeParmDecl *D) {

    // Only care about default arguments as part of the definition.

    const bool hasDefaultArgument =

        D->hasDefaultArgument() && 
!D->defaultArgumentWasInherited()3.15k
;

    Hash.AddBoolean(hasDefaultArgument);

    if (hasDefaultArgument) {

      AddTemplateArgument(D->getDefaultArgument());

    }

    Hash.AddBoolean(D->isParameterPack());

    const TypeConstraint *TC = D->getTypeConstraint();

    Hash.AddBoolean(TC != nullptr);

    if (TC)

      AddStmt(TC->getImmediatelyDeclaredConstraint());

    Inherited::VisitTemplateTypeParmDecl(D);

  }

  void VisitNonTypeTemplateParmDecl(const NonTypeTemplateParmDecl *D) {

    // Only care about default arguments as part of the definition.

    const bool hasDefaultArgument =

        D->hasDefaultArgument() && 
!D->defaultArgumentWasInherited()1.80k
;

    Hash.AddBoolean(hasDefaultArgument);

    if (hasDefaultArgument) {

      AddStmt(D->getDefaultArgument());

    }

    Hash.AddBoolean(D->isParameterPack());

    Inherited::VisitNonTypeTemplateParmDecl(D);

  }

  void VisitTemplateTemplateParmDecl(const TemplateTemplateParmDecl *D) {

    // Only care about default arguments as part of the definition.

    const bool hasDefaultArgument =

        D->hasDefaultArgument() && 
!D->defaultArgumentWasInherited()262
;

    Hash.AddBoolean(hasDefaultArgument);

    if (hasDefaultArgument) {

      AddTemplateArgument(D->getDefaultArgument().getArgument());

    }

    Hash.AddBoolean(D->isParameterPack());

    Inherited::VisitTemplateTemplateParmDecl(D);

  }

  void VisitTemplateDecl(const TemplateDecl *D) {

    Hash.AddTemplateParameterList(D->getTemplateParameters());

    Inherited::VisitTemplateDecl(D);

  }

  void VisitRedeclarableTemplateDecl(const RedeclarableTemplateDecl *D) {

    Hash.AddBoolean(D->isMemberSpecialization());

    Inherited::VisitRedeclarableTemplateDecl(D);

  }

  void VisitFunctionTemplateDecl(const FunctionTemplateDecl *D) {

    AddDecl(D->getTemplatedDecl());

    ID.AddInteger(D->getTemplatedDecl()->getODRHash());

    Inherited::VisitFunctionTemplateDecl(D);

  }

  void VisitEnumConstantDecl(const EnumConstantDecl *D) {

    AddStmt(D->getInitExpr());

    Inherited::VisitEnumConstantDecl(D);

  }

};

} // namespace

// Only allow a small portion of Decl's to be processed.  Remove this once

// all Decl's can be handled.

bool ODRHash::isDeclToBeProcessed(const Decl *D, const DeclContext *Parent) {

  if (D->isImplicit()) 
return false104k
;

  if (D->getDeclContext() != Parent) 
return false1.54k
;

  switch (D->getKind()) {

    default:

      return false;

    case Decl::AccessSpec:

    case Decl::CXXConstructor:

    case Decl::CXXDestructor:

    case Decl::CXXMethod:

    case Decl::EnumConstant: // Only found in EnumDecl's.

    case Decl::Field:

    case Decl::Friend:

    case Decl::FunctionTemplate:

    case Decl::StaticAssert:

    case Decl::TypeAlias:

    case Decl::Typedef:

    case Decl::Var:

      return true;

  }

}

void ODRHash::AddSubDecl(const Decl *D) {

  assert(D && "Expecting non-null pointer.");

  ODRDeclVisitor(ID, *this).Visit(D);

}

void ODRHash::AddCXXRecordDecl(const CXXRecordDecl *Record) {

  assert(Record && Record->hasDefinition() &&

         "Expected non-null record to be a definition.");

  const DeclContext *DC = Record;

  while (DC) {

    if (isa<ClassTemplateSpecializationDecl>(DC)) {

      return;

    }

    DC = DC->getParent();

  }

  AddDecl(Record);

  // Filter out sub-Decls which will not be processed in order to get an

  // accurate count of Decl's.

  llvm::SmallVector<const Decl *, 16> Decls;

  for (Decl *SubDecl : Record->decls()) {

    if (isDeclToBeProcessed(SubDecl, Record)) {

      Decls.push_back(SubDecl);

      if (auto *Function = dyn_cast<FunctionDecl>(SubDecl)) {

        // Compute/Preload ODRHash into FunctionDecl.

        Function->getODRHash();

      }

    }

  }

  ID.AddInteger(Decls.size());

  for (auto SubDecl : Decls) {

    AddSubDecl(SubDecl);

  }

  const ClassTemplateDecl *TD = Record->getDescribedClassTemplate();

  AddBoolean(TD);

  if (TD) {

    AddTemplateParameterList(TD->getTemplateParameters());

  }

  ID.AddInteger(Record->getNumBases());

  auto Bases = Record->bases();

  for (auto Base : Bases) {

    AddQualType(Base.getType());

    ID.AddInteger(Base.isVirtual());

    ID.AddInteger(Base.getAccessSpecifierAsWritten());

  }

}

void ODRHash::AddFunctionDecl(const FunctionDecl *Function,

                              bool SkipBody) {

  assert(Function && "Expecting non-null pointer.");

  // Skip functions that are specializations or in specialization context.

  const DeclContext *DC = Function;

  while (DC) {

    if (isa<ClassTemplateSpecializationDecl>(DC)) 
return43.3k
;

    if (auto *F = dyn_cast<FunctionDecl>(DC)) {

      if (F->isFunctionTemplateSpecialization()) {

        if (!isa<CXXMethodDecl>(DC)) 
return6.25k
;

        if (DC->getLexicalParent()->isFileContext()) 
return33
;

        // Inline method specializations are the only supported

        // specialization for now.

      }

    }

    DC = DC->getParent();

  }

  ID.AddInteger(Function->getDeclKind());

  const auto *SpecializationArgs = Function->getTemplateSpecializationArgs();

  AddBoolean(SpecializationArgs);

  if (SpecializationArgs) {

    ID.AddInteger(SpecializationArgs->size());

    for (const TemplateArgument &TA : SpecializationArgs->asArray()) {

      AddTemplateArgument(TA);

    }

  }

  if (const auto *Method = dyn_cast<CXXMethodDecl>(Function)) {

    AddBoolean(Method->isConst());

    AddBoolean(Method->isVolatile());

  }

  ID.AddInteger(Function->getStorageClass());

  AddBoolean(Function->isInlineSpecified());

  AddBoolean(Function->isVirtualAsWritten());

  AddBoolean(Function->isPure());

  AddBoolean(Function->isDeletedAsWritten());

  AddBoolean(Function->isExplicitlyDefaulted());

  AddDecl(Function);

  AddQualType(Function->getReturnType());

  ID.AddInteger(Function->param_size());

  for (auto Param : Function->parameters())

    AddSubDecl(Param);

  if (SkipBody) {

    AddBoolean(false);

    return;

  }

  const bool HasBody = Function->isThisDeclarationADefinition() &&

                       
!Function->isDefaulted()159k
 && 
!Function->isDeleted()149k
 &&

                       
!Function->isLateTemplateParsed()148k
;

  AddBoolean(HasBody);

  if (!HasBody) {

    return;

  }

  auto *Body = Function->getBody();

  AddBoolean(Body);

  if (Body)

    AddStmt(Body);

  // Filter out sub-Decls which will not be processed in order to get an

  // accurate count of Decl's.

  llvm::SmallVector<const Decl *, 16> Decls;

  for (Decl *SubDecl : Function->decls()) {

    if (isDeclToBeProcessed(SubDecl, Function)) {

      Decls.push_back(SubDecl);

    }

  }

  ID.AddInteger(Decls.size());

  for (auto SubDecl : Decls) {

    AddSubDecl(SubDecl);

  }

}

void ODRHash::AddEnumDecl(const EnumDecl *Enum) {

  assert(Enum);

  AddDeclarationName(Enum->getDeclName());

  AddBoolean(Enum->isScoped());

  if (Enum->isScoped())

    AddBoolean(Enum->isScopedUsingClassTag());

  if (Enum->getIntegerTypeSourceInfo())

    AddQualType(Enum->getIntegerType());

  // Filter out sub-Decls which will not be processed in order to get an

  // accurate count of Decl's.

  llvm::SmallVector<const Decl *, 16> Decls;

  for (Decl *SubDecl : Enum->decls()) {

    if (isDeclToBeProcessed(SubDecl, Enum)) {

      assert(isa<EnumConstantDecl>(SubDecl) && "Unexpected Decl");

      Decls.push_back(SubDecl);

    }

  }

  ID.AddInteger(Decls.size());

  for (auto SubDecl : Decls) {

    AddSubDecl(SubDecl);

  }

}

void ODRHash::AddDecl(const Decl *D) {

  assert(D && "Expecting non-null pointer.");

  D = D->getCanonicalDecl();

  const NamedDecl *ND = dyn_cast<NamedDecl>(D);

  AddBoolean(ND);

  if (!ND) {

    ID.AddInteger(D->getKind());

    return;

  }

  AddDeclarationName(ND->getDeclName());

  const auto *Specialization =

            dyn_cast<ClassTemplateSpecializationDecl>(D);

  AddBoolean(Specialization);

  if (Specialization) {

    const TemplateArgumentList &List = Specialization->getTemplateArgs();

    ID.AddInteger(List.size());

    for (const TemplateArgument &TA : List.asArray())

      AddTemplateArgument(TA);

  }

}

namespace {

// Process a Type pointer.  Add* methods call back into ODRHash while Visit*

// methods process the relevant parts of the Type.

class ODRTypeVisitor : public TypeVisitor<ODRTypeVisitor> {

  typedef TypeVisitor<ODRTypeVisitor> Inherited;

  llvm::FoldingSetNodeID &ID;

  ODRHash &Hash;

public:

  ODRTypeVisitor(llvm::FoldingSetNodeID &ID, ODRHash &Hash)

      : ID(ID), Hash(Hash) {}

  void AddStmt(Stmt *S) {

    Hash.AddBoolean(S);

    if (S) {

      Hash.AddStmt(S);

    }

  }

  void AddDecl(Decl *D) {

    Hash.AddBoolean(D);

    if (D) {

      Hash.AddDecl(D);

    }

  }

  void AddQualType(QualType T) {

    Hash.AddQualType(T);

  }

  void AddType(const Type *T) {

    Hash.AddBoolean(T);

    if (T) {

      Hash.AddType(T);

    }

  }

  void AddNestedNameSpecifier(const NestedNameSpecifier *NNS) {

    Hash.AddBoolean(NNS);

    if (NNS) {

      Hash.AddNestedNameSpecifier(NNS);

    }

  }

  void AddIdentifierInfo(const IdentifierInfo *II) {

    Hash.AddBoolean(II);

    if (II) {

      Hash.AddIdentifierInfo(II);

    }

  }

  void VisitQualifiers(Qualifiers Quals) {

    ID.AddInteger(Quals.getAsOpaqueValue());

  }

  // Return the RecordType if the typedef only strips away a keyword.

  // Otherwise, return the original type.

  static const Type *RemoveTypedef(const Type *T) {

    const auto *TypedefT = dyn_cast<TypedefType>(T);

    if (!TypedefT) {

      return T;

    }

    const TypedefNameDecl *D = TypedefT->getDecl();

    QualType UnderlyingType = D->getUnderlyingType();

    if (UnderlyingType.hasLocalQualifiers()) {

      return T;

    }

    const auto *ElaboratedT = dyn_cast<ElaboratedType>(UnderlyingType);

    if (!ElaboratedT) {

      return T;

    }

    if (ElaboratedT->getQualifier() != nullptr) {

      return T;

    }

    QualType NamedType = ElaboratedT->getNamedType();

    if (NamedType.hasLocalQualifiers()) {

      return T;

    }

    const auto *RecordT = dyn_cast<RecordType>(NamedType);

    if (!RecordT) {

      return T;

    }

    const IdentifierInfo *TypedefII = TypedefT->getDecl()->getIdentifier();

    const IdentifierInfo *RecordII = RecordT->getDecl()->getIdentifier();

    if (!TypedefII || !RecordII ||

        
TypedefII->getName() != RecordII->getName()33.4k
) {

      return T;

    }

    return RecordT;

  }

  void Visit(const Type *T) {

    T = RemoveTypedef(T);

    ID.AddInteger(T->getTypeClass());

    Inherited::Visit(T);

  }

  void VisitType(const Type *T) {}

  void VisitAdjustedType(const AdjustedType *T) {

    QualType Original = T->getOriginalType();

    QualType Adjusted = T->getAdjustedType();

    // The original type and pointee type can be the same, as in the case of

    // function pointers decaying to themselves.  Set a bool and only process

    // the type once, to prevent doubling the work.

    SplitQualType split = Adjusted.split();

    if (auto Pointer = dyn_cast<PointerType>(split.Ty)) {

      if (Pointer->getPointeeType() == Original) {

        Hash.AddBoolean(true);

        ID.AddInteger(split.Quals.getAsOpaqueValue());

        AddQualType(Original);

        VisitType(T);

        return;

      }

    }

    // The original type and pointee type are different, such as in the case

    // of a array decaying to an element pointer.  Set a bool to false and

    // process both types.

    Hash.AddBoolean(false);

    AddQualType(Original);

    AddQualType(Adjusted);

    VisitType(T);

  }

  void VisitDecayedType(const DecayedType *T) {

    // getDecayedType and getPointeeType are derived from getAdjustedType

    // and don't need to be separately processed.

    VisitAdjustedType(T);

  }

  void VisitArrayType(const ArrayType *T) {

    AddQualType(T->getElementType());

    ID.AddInteger(T->getSizeModifier());

    VisitQualifiers(T->getIndexTypeQualifiers());

    VisitType(T);

  }

  void VisitConstantArrayType(const ConstantArrayType *T) {

    T->getSize().Profile(ID);

    VisitArrayType(T);

  }

  void VisitDependentSizedArrayType(const DependentSizedArrayType *T) {

    AddStmt(T->getSizeExpr());

    VisitArrayType(T);

  }

  void VisitIncompleteArrayType(const IncompleteArrayType *T) {

    VisitArrayType(T);

  }

  void VisitVariableArrayType(const VariableArrayType *T) {

    AddStmt(T->getSizeExpr());

    VisitArrayType(T);

  }

  void VisitAttributedType(const AttributedType *T) {

    ID.AddInteger(T->getAttrKind());

    AddQualType(T->getModifiedType());

    AddQualType(T->getEquivalentType());

    VisitType(T);

  }

  void VisitBlockPointerType(const BlockPointerType *T) {

    AddQualType(T->getPointeeType());

    VisitType(T);

  }

  void VisitBuiltinType(const BuiltinType *T) {

    ID.AddInteger(T->getKind());

    VisitType(T);

  }

  void VisitComplexType(const ComplexType *T) {

    AddQualType(T->getElementType());

    VisitType(T);

  }

  void VisitDecltypeType(const DecltypeType *T) {

    AddStmt(T->getUnderlyingExpr());

    AddQualType(T->getUnderlyingType());

    VisitType(T);

  }

  void VisitDependentDecltypeType(const DependentDecltypeType *T) {

    VisitDecltypeType(T);

  }

  void VisitDeducedType(const DeducedType *T) {

    AddQualType(T->getDeducedType());

    VisitType(T);

  }

  void VisitAutoType(const AutoType *T) {

    ID.AddInteger((unsigned)T->getKeyword());

    ID.AddInteger(T->isConstrained());

    if (T->isConstrained()) {

      AddDecl(T->getTypeConstraintConcept());

      ID.AddInteger(T->getNumArgs());

      for (const auto &TA : T->getTypeConstraintArguments())

        Hash.AddTemplateArgument(TA);

    }

    VisitDeducedType(T);

  }

  void VisitDeducedTemplateSpecializationType(

      const DeducedTemplateSpecializationType *T) {

    Hash.AddTemplateName(T->getTemplateName());

    VisitDeducedType(T);

  }

  void VisitDependentAddressSpaceType(const DependentAddressSpaceType *T) {

    AddQualType(T->getPointeeType());

    AddStmt(T->getAddrSpaceExpr());

    VisitType(T);

  }

  void VisitDependentSizedExtVectorType(const DependentSizedExtVectorType *T) {

    AddQualType(T->getElementType());

    AddStmt(T->getSizeExpr());

    VisitType(T);

  }

  void VisitFunctionType(const FunctionType *T) {

    AddQualType(T->getReturnType());

    T->getExtInfo().Profile(ID);

    Hash.AddBoolean(T->isConst());

    Hash.AddBoolean(T->isVolatile());

    Hash.AddBoolean(T->isRestrict());

    VisitType(T);

  }

  void VisitFunctionNoProtoType(const FunctionNoProtoType *T) {

    VisitFunctionType(T);

  }

  void VisitFunctionProtoType(const FunctionProtoType *T) {

    ID.AddInteger(T->getNumParams());

    for (auto ParamType : T->getParamTypes())

      AddQualType(ParamType);

    VisitFunctionType(T);

  }

  void VisitInjectedClassNameType(const InjectedClassNameType *T) {

    AddDecl(T->getDecl());

    VisitType(T);

  }

  void VisitMemberPointerType(const MemberPointerType *T) {

    AddQualType(T->getPointeeType());

    AddType(T->getClass());

    VisitType(T);

  }

  void VisitObjCObjectPointerType(const ObjCObjectPointerType *T) {

    AddQualType(T->getPointeeType());

    VisitType(T);

  }

  void VisitObjCObjectType(const ObjCObjectType *T) {

    AddDecl(T->getInterface());

    auto TypeArgs = T->getTypeArgsAsWritten();

    ID.AddInteger(TypeArgs.size());

    for (auto Arg : TypeArgs) {

      AddQualType(Arg);

    }

    auto Protocols = T->getProtocols();

    ID.AddInteger(Protocols.size());

    for (auto Protocol : Protocols) {

      AddDecl(Protocol);

    }

    Hash.AddBoolean(T->isKindOfType());

    VisitType(T);

  }

  void VisitObjCInterfaceType(const ObjCInterfaceType *T) {

    // This type is handled by the parent type ObjCObjectType.

    VisitObjCObjectType(T);

  }

  void VisitObjCTypeParamType(const ObjCTypeParamType *T) {

    AddDecl(T->getDecl());

    auto Protocols = T->getProtocols();

    ID.AddInteger(Protocols.size());

    for (auto Protocol : Protocols) {

      AddDecl(Protocol);

    }

    VisitType(T);

  }

  void VisitPackExpansionType(const PackExpansionType *T) {

    AddQualType(T->getPattern());

    VisitType(T);

  }

  void VisitParenType(const ParenType *T) {

    AddQualType(T->getInnerType());

    VisitType(T);

  }

  void VisitPipeType(const PipeType *T) {

    AddQualType(T->getElementType());

    Hash.AddBoolean(T->isReadOnly());

    VisitType(T);

  }

  void VisitPointerType(const PointerType *T) {

    AddQualType(T->getPointeeType());

    VisitType(T);

  }

  void VisitReferenceType(const ReferenceType *T) {

    AddQualType(T->getPointeeTypeAsWritten());

    VisitType(T);

  }

  void VisitLValueReferenceType(const LValueReferenceType *T) {

    VisitReferenceType(T);

  }

  void VisitRValueReferenceType(const RValueReferenceType *T) {

    VisitReferenceType(T);

  }

  void

  VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {

    AddType(T->getReplacedParameter());

    Hash.AddTemplateArgument(T->getArgumentPack());

    VisitType(T);

  }

  void VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {

    AddType(T->getReplacedParameter());

    AddQualType(T->getReplacementType());

    VisitType(T);

  }

  void VisitTagType(const TagType *T) {

    AddDecl(T->getDecl());

    VisitType(T);

  }

  void VisitRecordType(const RecordType *T) { VisitTagType(T); }

  void VisitEnumType(const EnumType *T) { VisitTagType(T); }

  void VisitTemplateSpecializationType(const TemplateSpecializationType *T) {

    ID.AddInteger(T->getNumArgs());

    for (const auto &TA : T->template_arguments()) {