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
24namespace clang {
25
26class Decl;
27class IdentifierInfo;
28class NestedNameSpecifier;
29class Stmt;
30class 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.
39class 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
49public:
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