1 //===-- ODRHash.h - Hashing to diagnose ODR failures ------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 /// 10 /// \file 11 /// This file contains the declaration of the ODRHash class, which calculates 12 /// a hash based on AST nodes, which is stable across different runs. 13 /// 14 //===----------------------------------------------------------------------===// 15 16 #include "clang/AST/DeclarationName.h" 17 #include "clang/AST/Type.h" 18 #include "clang/AST/TemplateBase.h" 19 #include "llvm/ADT/DenseMap.h" 20 #include "llvm/ADT/FoldingSet.h" 21 #include "llvm/ADT/PointerUnion.h" 22 #include "llvm/ADT/SmallVector.h" 23 24 namespace clang { 25 26 class Decl; 27 class IdentifierInfo; 28 class NestedNameSpecifier; 29 class Stmt; 30 class TemplateParameterList; 31 32 // ODRHash is used to calculate a hash based on AST node contents that 33 // does not rely on pointer addresses. This allows the hash to not vary 34 // between runs and is usable to detect ODR problems in modules. To use, 35 // construct an ODRHash object, then call Add* methods over the nodes that 36 // need to be hashed. Then call CalculateHash to get the hash value. 37 // Typically, only one Add* call is needed. clear can be called to reuse the 38 // object. 39 class ODRHash { 40 // Use DenseMaps to convert between Decl and Type pointers and an index value. 41 llvm::DenseMap<const Decl*, unsigned> DeclMap; 42 llvm::DenseMap<const Type*, unsigned> TypeMap; 43 44 // Save space by processing bools at the end. 45 llvm::SmallVector<bool, 128> Bools; 46 47 llvm::FoldingSetNodeID ID; 48 49 public: 50 ODRHash() {} 51 52 // Use this for ODR checking classes between modules. This method compares 53 // more information than the AddDecl class. 54 void AddCXXRecordDecl(const CXXRecordDecl *Record); 55 56 // Process SubDecls of the main Decl. This method calls the DeclVisitor 57 // while AddDecl does not. 58 void AddSubDecl(const Decl *D); 59 60 // Reset the object for reuse. 61 void clear(); 62 63 // Add booleans to ID and uses it to calculate the hash. 64 unsigned CalculateHash(); 65 66 // Add AST nodes that need to be processed. 67 void AddDecl(const Decl *D); 68 void AddType(const Type *T); 69 void AddQualType(QualType T); 70 void AddStmt(const Stmt *S); 71 void AddIdentifierInfo(const IdentifierInfo *II); 72 void AddNestedNameSpecifier(const NestedNameSpecifier *NNS); 73 void AddTemplateName(TemplateName Name); 74 void AddDeclarationName(DeclarationName Name); 75 void AddTemplateArgument(TemplateArgument TA); 76 void AddTemplateParameterList(const TemplateParameterList *TPL); 77 78 // Save booleans until the end to lower the size of data to process. 79 void AddBoolean(bool value); 80 81 static bool isWhitelistedDecl(const Decl* D, const CXXRecordDecl *Record); 82 }; 83 84 } // end namespace clang 85