1 //===--- CodeGenTBAA.h - TBAA information for LLVM CodeGen ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This is the code that manages TBAA information and defines the TBAA policy
11 // for the optimizer to use.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENTBAA_H
16 #define LLVM_CLANG_LIB_CODEGEN_CODEGENTBAA_H
18 #include "clang/Basic/LLVM.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/IR/MDBuilder.h"
39 TBAAPathTag(const Type *B, const llvm::MDNode *A, uint64_t O)
40 : BaseT(B), AccessN(A), Offset(O) {}
42 const llvm::MDNode *AccessN;
46 /// CodeGenTBAA - This class organizes the cross-module state that is used
47 /// while lowering AST types to LLVM types.
50 const CodeGenOptions &CodeGenOpts;
51 const LangOptions &Features;
52 MangleContext &MContext;
54 // MDHelper - Helper for creating metadata.
55 llvm::MDBuilder MDHelper;
57 /// MetadataCache - This maps clang::Types to scalar llvm::MDNodes describing
59 llvm::DenseMap<const Type *, llvm::MDNode *> MetadataCache;
60 /// This maps clang::Types to a struct node in the type DAG.
61 llvm::DenseMap<const Type *, llvm::MDNode *> StructTypeMetadataCache;
62 /// This maps TBAAPathTags to a tag node.
63 llvm::DenseMap<TBAAPathTag, llvm::MDNode *> StructTagMetadataCache;
64 /// This maps a scalar type to a scalar tag node.
65 llvm::DenseMap<const llvm::MDNode *, llvm::MDNode *> ScalarTagMetadataCache;
67 /// StructMetadataCache - This maps clang::Types to llvm::MDNodes describing
68 /// them for struct assignments.
69 llvm::DenseMap<const Type *, llvm::MDNode *> StructMetadataCache;
74 /// getRoot - This is the mdnode for the root of the metadata type graph
75 /// for this translation unit.
76 llvm::MDNode *getRoot();
78 /// getChar - This is the mdnode for "char", which is special, and any types
79 /// considered to be equivalent to it.
80 llvm::MDNode *getChar();
82 /// CollectFields - Collect information about the fields of a type for
83 /// !tbaa.struct metadata formation. Return false for an unsupported type.
84 bool CollectFields(uint64_t BaseOffset,
86 SmallVectorImpl<llvm::MDBuilder::TBAAStructField> &Fields,
89 /// A wrapper function to create a scalar type. For struct-path aware TBAA,
90 /// the scalar type has the same format as the struct type: name, offset,
91 /// pointer to another node in the type DAG.
92 llvm::MDNode *createTBAAScalarType(StringRef Name, llvm::MDNode *Parent);
95 CodeGenTBAA(ASTContext &Ctx, llvm::LLVMContext &VMContext,
96 const CodeGenOptions &CGO,
97 const LangOptions &Features,
98 MangleContext &MContext);
101 /// getTBAAInfo - Get the TBAA MDNode to be used for a dereference
102 /// of the given type.
103 llvm::MDNode *getTBAAInfo(QualType QTy);
105 /// getTBAAInfoForVTablePtr - Get the TBAA MDNode to be used for a
106 /// dereference of a vtable pointer.
107 llvm::MDNode *getTBAAInfoForVTablePtr();
109 /// getTBAAStructInfo - Get the TBAAStruct MDNode to be used for a memcpy of
111 llvm::MDNode *getTBAAStructInfo(QualType QTy);
113 /// Get the MDNode in the type DAG for given struct type QType.
114 llvm::MDNode *getTBAAStructTypeInfo(QualType QType);
115 /// Get the tag MDNode for a given base type, the actual scalar access MDNode
116 /// and offset into the base type.
117 llvm::MDNode *getTBAAStructTagInfo(QualType BaseQType,
118 llvm::MDNode *AccessNode, uint64_t Offset);
120 /// Get the scalar tag MDNode for a given scalar type.
121 llvm::MDNode *getTBAAScalarTagInfo(llvm::MDNode *AccessNode);
124 } // end namespace CodeGen
125 } // end namespace clang
129 template<> struct DenseMapInfo<clang::CodeGen::TBAAPathTag> {
130 static clang::CodeGen::TBAAPathTag getEmptyKey() {
131 return clang::CodeGen::TBAAPathTag(
132 DenseMapInfo<const clang::Type *>::getEmptyKey(),
133 DenseMapInfo<const MDNode *>::getEmptyKey(),
134 DenseMapInfo<uint64_t>::getEmptyKey());
137 static clang::CodeGen::TBAAPathTag getTombstoneKey() {
138 return clang::CodeGen::TBAAPathTag(
139 DenseMapInfo<const clang::Type *>::getTombstoneKey(),
140 DenseMapInfo<const MDNode *>::getTombstoneKey(),
141 DenseMapInfo<uint64_t>::getTombstoneKey());
144 static unsigned getHashValue(const clang::CodeGen::TBAAPathTag &Val) {
145 return DenseMapInfo<const clang::Type *>::getHashValue(Val.BaseT) ^
146 DenseMapInfo<const MDNode *>::getHashValue(Val.AccessN) ^
147 DenseMapInfo<uint64_t>::getHashValue(Val.Offset);
150 static bool isEqual(const clang::CodeGen::TBAAPathTag &LHS,
151 const clang::CodeGen::TBAAPathTag &RHS) {
152 return LHS.BaseT == RHS.BaseT &&
153 LHS.AccessN == RHS.AccessN &&
154 LHS.Offset == RHS.Offset;
158 } // end namespace llvm