- //===-- ODRHash.h - 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 contains the declaration of the ODRHash class, which calculates 
- /// a hash based on AST nodes, which is stable across different runs. 
- /// 
- //===----------------------------------------------------------------------===// 
-   
- #ifndef LLVM_CLANG_AST_ODRHASH_H 
- #define LLVM_CLANG_AST_ODRHASH_H 
-   
- #include "clang/AST/DeclarationName.h" 
- #include "clang/AST/Type.h" 
- #include "clang/AST/TemplateBase.h" 
- #include "llvm/ADT/DenseMap.h" 
- #include "llvm/ADT/FoldingSet.h" 
- #include "llvm/ADT/PointerUnion.h" 
- #include "llvm/ADT/SmallVector.h" 
-   
- namespace clang { 
-   
- class Decl; 
- class IdentifierInfo; 
- class NestedNameSpecifier; 
- class Stmt; 
- class TemplateParameterList; 
-   
- // ODRHash is used to calculate a hash based on AST node contents that 
- // does not rely on pointer addresses.  This allows the hash to not vary 
- // between runs and is usable to detect ODR problems in modules.  To use, 
- // construct an ODRHash object, then call Add* methods over the nodes that 
- // need to be hashed.  Then call CalculateHash to get the hash value. 
- // Typically, only one Add* call is needed.  clear can be called to reuse the 
- // object. 
- class ODRHash { 
-   // Use DenseMaps to convert from DeclarationName and Type pointers 
-   // to an index value. 
-   llvm::DenseMap<DeclarationName, unsigned> DeclNameMap; 
-   
-   // Save space by processing bools at the end. 
-   llvm::SmallVector<bool, 128> Bools; 
-   
-   llvm::FoldingSetNodeID ID; 
-   
- public: 
-   ODRHash() {} 
-   
-   // Use this for ODR checking classes between modules.  This method compares 
-   // more information than the AddDecl class. 
-   void AddCXXRecordDecl(const CXXRecordDecl *Record); 
-   
-   // Use this for ODR checking records in C/Objective-C between modules. This 
-   // method compares more information than the AddDecl class. 
-   void AddRecordDecl(const RecordDecl *Record); 
-   
-   // Use this for ODR checking ObjC interfaces. This 
-   // method compares more information than the AddDecl class. 
-   void AddObjCInterfaceDecl(const ObjCInterfaceDecl *Record); 
-   
-   // Use this for ODR checking functions between modules.  This method compares 
-   // more information than the AddDecl class.  SkipBody will process the 
-   // hash as if the function has no body. 
-   void AddFunctionDecl(const FunctionDecl *Function, bool SkipBody = false); 
-   
-   // Use this for ODR checking enums between modules.  This method compares 
-   // more information than the AddDecl class. 
-   void AddEnumDecl(const EnumDecl *Enum); 
-   
-   // Use this for ODR checking ObjC protocols. This 
-   // method compares more information than the AddDecl class. 
-   void AddObjCProtocolDecl(const ObjCProtocolDecl *P); 
-   
-   // Process SubDecls of the main Decl.  This method calls the DeclVisitor 
-   // while AddDecl does not. 
-   void AddSubDecl(const Decl *D); 
-   
-   // Reset the object for reuse. 
-   void clear(); 
-   
-   // Add booleans to ID and uses it to calculate the hash. 
-   unsigned CalculateHash(); 
-   
-   // Add AST nodes that need to be processed. 
-   void AddDecl(const Decl *D); 
-   void AddType(const Type *T); 
-   void AddQualType(QualType T); 
-   void AddStmt(const Stmt *S); 
-   void AddIdentifierInfo(const IdentifierInfo *II); 
-   void AddNestedNameSpecifier(const NestedNameSpecifier *NNS); 
-   void AddTemplateName(TemplateName Name); 
-   void AddDeclarationName(DeclarationName Name, bool TreatAsDecl = false); 
-   void AddTemplateArgument(TemplateArgument TA); 
-   void AddTemplateParameterList(const TemplateParameterList *TPL); 
-   
-   // Save booleans until the end to lower the size of data to process. 
-   void AddBoolean(bool value); 
-   
-   static bool isSubDeclToBeProcessed(const Decl *D, const DeclContext *Parent); 
-   
- private: 
-   void AddDeclarationNameImpl(DeclarationName Name); 
- }; 
-   
- }  // end namespace clang 
-   
- #endif 
-