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 APValue; 29 class Decl; 30 class IdentifierInfo; 31 class NestedNameSpecifier; 32 class Stmt; 33 class TemplateParameterList; 34 35 // ODRHash is used to calculate a hash based on AST node contents that 36 // does not rely on pointer addresses. This allows the hash to not vary 37 // between runs and is usable to detect ODR problems in modules. To use, 38 // construct an ODRHash object, then call Add* methods over the nodes that 39 // need to be hashed. Then call CalculateHash to get the hash value. 40 // Typically, only one Add* call is needed. clear can be called to reuse the 41 // object. 42 class ODRHash { 43 // Use DenseMaps to convert from DeclarationName and Type pointers 44 // to an index value. 45 llvm::DenseMap<DeclarationName, unsigned> DeclNameMap; 46 47 // Save space by processing bools at the end. 48 llvm::SmallVector<bool, 128> Bools; 49 50 llvm::FoldingSetNodeID ID; 51 52 public: ODRHash()53 ODRHash() {} 54 55 // Use this for ODR checking classes between modules. This method compares 56 // more information than the AddDecl class. 57 void AddCXXRecordDecl(const CXXRecordDecl *Record); 58 59 // Use this for ODR checking records in C/Objective-C between modules. This 60 // method compares more information than the AddDecl class. 61 void AddRecordDecl(const RecordDecl *Record); 62 63 // Use this for ODR checking ObjC interfaces. This 64 // method compares more information than the AddDecl class. 65 void AddObjCInterfaceDecl(const ObjCInterfaceDecl *Record); 66 67 // Use this for ODR checking functions between modules. This method compares 68 // more information than the AddDecl class. SkipBody will process the 69 // hash as if the function has no body. 70 void AddFunctionDecl(const FunctionDecl *Function, bool SkipBody = false); 71 72 // Use this for ODR checking enums between modules. This method compares 73 // more information than the AddDecl class. 74 void AddEnumDecl(const EnumDecl *Enum); 75 76 // Use this for ODR checking ObjC protocols. This 77 // method compares more information than the AddDecl class. 78 void AddObjCProtocolDecl(const ObjCProtocolDecl *P); 79 80 // Process SubDecls of the main Decl. This method calls the DeclVisitor 81 // while AddDecl does not. 82 void AddSubDecl(const Decl *D); 83 84 // Reset the object for reuse. 85 void clear(); 86 87 // Add booleans to ID and uses it to calculate the hash. 88 unsigned CalculateHash(); 89 90 // Add AST nodes that need to be processed. 91 void AddDecl(const Decl *D); 92 void AddType(const Type *T); 93 void AddQualType(QualType T); 94 void AddStmt(const Stmt *S); 95 void AddIdentifierInfo(const IdentifierInfo *II); 96 void AddNestedNameSpecifier(const NestedNameSpecifier *NNS); 97 void AddTemplateName(TemplateName Name); 98 void AddDeclarationName(DeclarationName Name, bool TreatAsDecl = false); 99 void AddTemplateArgument(TemplateArgument TA); 100 void AddTemplateParameterList(const TemplateParameterList *TPL); 101 102 // Save booleans until the end to lower the size of data to process. 103 void AddBoolean(bool value); 104 105 void AddStructuralValue(const APValue &); 106 107 static bool isSubDeclToBeProcessed(const Decl *D, const DeclContext *Parent); 108 109 private: 110 void AddDeclarationNameImpl(DeclarationName Name); 111 }; 112 113 } // end namespace clang 114 115 #endif 116