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
26namespace clang {
27
28class Decl;
29class IdentifierInfo;
30class NestedNameSpecifier;
31class Stmt;
32class 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.
41class 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
51public:
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 isWhitelistedDecl(const Decl* D, const DeclContext *Parent);
93
94private:
95  void AddDeclarationNameImpl(DeclarationName Name);
96};
97
98}  // end namespace clang
99
100#endif
101