1 //===-- ODRHash.h - Hashing to diagnose ODR failures ------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// 9 /// \file 10 /// This file contains the declaration of the ODRHash class, which calculates 11 /// a hash based on AST nodes, which is stable across different runs. 12 /// 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_AST_ODRHASH_H 16 #define LLVM_CLANG_AST_ODRHASH_H 17 18 #include "clang/AST/DeclarationName.h" 19 #include "clang/AST/Type.h" 20 #include "clang/AST/TemplateBase.h" 21 #include "llvm/ADT/DenseMap.h" 22 #include "llvm/ADT/FoldingSet.h" 23 #include "llvm/ADT/PointerUnion.h" 24 #include "llvm/ADT/SmallVector.h" 25 26 namespace clang { 27 28 class Decl; 29 class IdentifierInfo; 30 class NestedNameSpecifier; 31 class Stmt; 32 class TemplateParameterList; 33 34 // ODRHash is used to calculate a hash based on AST node contents that 35 // does not rely on pointer addresses. This allows the hash to not vary 36 // between runs and is usable to detect ODR problems in modules. To use, 37 // construct an ODRHash object, then call Add* methods over the nodes that 38 // need to be hashed. Then call CalculateHash to get the hash value. 39 // Typically, only one Add* call is needed. clear can be called to reuse the 40 // object. 41 class ODRHash { 42 // Use DenseMaps to convert from DeclarationName and Type pointers 43 // to an index value. 44 llvm::DenseMap<DeclarationName, unsigned> DeclNameMap; 45 46 // Save space by processing bools at the end. 47 llvm::SmallVector<bool, 128> Bools; 48 49 llvm::FoldingSetNodeID ID; 50 51 public: ODRHash()52 ODRHash() {} 53 54 // Use this for ODR checking classes between modules. This method compares 55 // more information than the AddDecl class. 56 void AddCXXRecordDecl(const CXXRecordDecl *Record); 57 58 // Use this for ODR checking functions between modules. This method compares 59 // more information than the AddDecl class. SkipBody will process the 60 // hash as if the function has no body. 61 void AddFunctionDecl(const FunctionDecl *Function, bool SkipBody = false); 62 63 // Use this for ODR checking enums between modules. This method compares 64 // more information than the AddDecl class. 65 void AddEnumDecl(const EnumDecl *Enum); 66 67 // Process SubDecls of the main Decl. This method calls the DeclVisitor 68 // while AddDecl does not. 69 void AddSubDecl(const Decl *D); 70 71 // Reset the object for reuse. 72 void clear(); 73 74 // Add booleans to ID and uses it to calculate the hash. 75 unsigned CalculateHash(); 76 77 // Add AST nodes that need to be processed. 78 void AddDecl(const Decl *D); 79 void AddType(const Type *T); 80 void AddQualType(QualType T); 81 void AddStmt(const Stmt *S); 82 void AddIdentifierInfo(const IdentifierInfo *II); 83 void AddNestedNameSpecifier(const NestedNameSpecifier *NNS); 84 void AddTemplateName(TemplateName Name); 85 void AddDeclarationName(DeclarationName Name, bool TreatAsDecl = false); 86 void AddTemplateArgument(TemplateArgument TA); 87 void AddTemplateParameterList(const TemplateParameterList *TPL); 88 89 // Save booleans until the end to lower the size of data to process. 90 void AddBoolean(bool value); 91 92 static bool isDeclToBeProcessed(const Decl* D, const DeclContext *Parent); 93 94 private: 95 void AddDeclarationNameImpl(DeclarationName Name); 96 }; 97 98 } // end namespace clang 99 100 #endif 101