CodeGenTypes.h revision 72564e73277e29f6db3305d1f27ba408abb7ed88 
1//===--- CodeGenTypes.h - Type translation for LLVM CodeGen -----*- 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// This is the code that handles AST -> LLVM type lowering.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef CLANG_CODEGEN_CODEGENTYPES_H
15#define CLANG_CODEGEN_CODEGENTYPES_H
16
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/SmallSet.h"
19#include <vector>
20
21#include "CGCall.h"
22
23namespace llvm {
24  class FunctionType;
25  class Module;
26  class OpaqueType;
27  class PATypeHolder;
28  class TargetData;
29  class Type;
30}
31
32namespace clang {
33  class ABIInfo;
34  class ASTContext;
35  class FieldDecl;
36  class FunctionProtoType;
37  class ObjCInterfaceDecl;
38  class ObjCIvarDecl;
39  class PointerType;
40  class QualType;
41  class RecordDecl;
42  class TagDecl;
43  class TargetInfo;
44  class Type;
45
46namespace CodeGen {
47  class CodeGenTypes;
48
49  /// CGRecordLayout - This class handles struct and union layout info while
50  /// lowering AST types to LLVM types.
51  class CGRecordLayout {
52    CGRecordLayout(); // DO NOT IMPLEMENT
53  public:
54    CGRecordLayout(llvm::Type *T, llvm::SmallSet<unsigned, 8> &PF)
55      : STy(T), PaddingFields(PF) {
56      // FIXME : Collect info about fields that requires adjustments
57      // (i.e. fields that do not directly map to llvm struct fields.)
58    }
59
60    /// getLLVMType - Return llvm type associated with this record.
61    llvm::Type *getLLVMType() const {
62      return STy;
63    }
64
65    bool isPaddingField(unsigned No) const {
66      return PaddingFields.count(No) != 0;
67    }
68
69    unsigned getNumPaddingFields() {
70      return PaddingFields.size();
71    }
72
73  private:
74    llvm::Type *STy;
75    llvm::SmallSet<unsigned, 8> PaddingFields;
76  };
77
78/// CodeGenTypes - This class organizes the cross-module state that is used
79/// while lowering AST types to LLVM types.
80class CodeGenTypes {
81  ASTContext &Context;
82  TargetInfo &Target;
83  llvm::Module& TheModule;
84  const llvm::TargetData& TheTargetData;
85  mutable const ABIInfo* TheABIInfo;
86
87  llvm::SmallVector<std::pair<QualType,
88                              llvm::OpaqueType *>, 8>  PointersToResolve;
89
90  llvm::DenseMap<const Type*, llvm::PATypeHolder> TagDeclTypes;
91
92  /// CGRecordLayouts - This maps llvm struct type with corresponding
93  /// record layout info.
94  /// FIXME : If CGRecordLayout is less than 16 bytes then use
95  /// inline it in the map.
96  llvm::DenseMap<const Type*, CGRecordLayout *> CGRecordLayouts;
97
98  /// FieldInfo - This maps struct field with corresponding llvm struct type
99  /// field no. This info is populated by record organizer.
100  llvm::DenseMap<const FieldDecl *, unsigned> FieldInfo;
101
102  /// FunctionInfos - Hold memoized CGFunctionInfo results.
103  llvm::FoldingSet<CGFunctionInfo> FunctionInfos;
104
105public:
106  class BitFieldInfo {
107  public:
108    explicit BitFieldInfo(unsigned short B, unsigned short S)
109      : Begin(B), Size(S) {}
110
111    unsigned short Begin;
112    unsigned short Size;
113  };
114
115private:
116  llvm::DenseMap<const FieldDecl *, BitFieldInfo> BitFields;
117
118  /// TypeCache - This map keeps cache of llvm::Types (through PATypeHolder)
119  /// and maps llvm::Types to corresponding clang::Type. llvm::PATypeHolder is
120  /// used instead of llvm::Type because it allows us to bypass potential
121  /// dangling type pointers due to type refinement on llvm side.
122  llvm::DenseMap<Type *, llvm::PATypeHolder> TypeCache;
123
124  /// ConvertNewType - Convert type T into a llvm::Type. Do not use this
125  /// method directly because it does not do any type caching. This method
126  /// is available only for ConvertType(). CovertType() is preferred
127  /// interface to convert type T into a llvm::Type.
128  const llvm::Type *ConvertNewType(QualType T);
129public:
130  CodeGenTypes(ASTContext &Ctx, llvm::Module &M, const llvm::TargetData &TD);
131  ~CodeGenTypes();
132
133  const llvm::TargetData &getTargetData() const { return TheTargetData; }
134  TargetInfo &getTarget() const { return Target; }
135  ASTContext &getContext() const { return Context; }
136  const ABIInfo &getABIInfo() const;
137
138  /// ConvertType - Convert type T into a llvm::Type.
139  const llvm::Type *ConvertType(QualType T);
140  const llvm::Type *ConvertTypeRecursive(QualType T);
141
142  /// ConvertTypeForMem - Convert type T into a llvm::Type.  This differs from
143  /// ConvertType in that it is used to convert to the memory representation for
144  /// a type.  For example, the scalar representation for _Bool is i1, but the
145  /// memory representation is usually i8 or i32, depending on the target.
146  const llvm::Type *ConvertTypeForMem(QualType T);
147
148  /// GetFunctionType - Get the LLVM function type for \arg Info.
149  const llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info,
150                                            bool IsVariadic);
151
152  const CGRecordLayout *getCGRecordLayout(const TagDecl*) const;
153  /// Returns a StructType representing an Objective-C object
154  const llvm::Type *ConvertObjCInterfaceToStruct(const ObjCInterfaceDecl *OID);
155
156  /// getLLVMFieldNo - Return llvm::StructType element number
157  /// that corresponds to the field FD.
158  unsigned getLLVMFieldNo(const FieldDecl *FD);
159
160  /// UpdateCompletedType - When we find the full definition for a TagDecl,
161  /// replace the 'opaque' type we previously made for it if applicable.
162  void UpdateCompletedType(const TagDecl *TD);
163
164  /// getFunctionInfo - Get the CGFunctionInfo for this function signature.
165  const CGFunctionInfo &getFunctionInfo(QualType RetTy,
166                                        const llvm::SmallVector<QualType,16>
167                                        &ArgTys);
168
169  const CGFunctionInfo &getFunctionInfo(const FunctionNoProtoType *FTNP);
170  const CGFunctionInfo &getFunctionInfo(const FunctionProtoType *FTP);
171  const CGFunctionInfo &getFunctionInfo(const FunctionDecl *FD);
172  const CGFunctionInfo &getFunctionInfo(const ObjCMethodDecl *MD);
173  const CGFunctionInfo &getFunctionInfo(QualType ResTy,
174                                        const CallArgList &Args);
175  const CGFunctionInfo &getFunctionInfo(QualType ResTy,
176                                        const FunctionArgList &Args);
177
178public:  // These are internal details of CGT that shouldn't be used externally.
179  /// addFieldInfo - Assign field number to field FD.
180  void addFieldInfo(const FieldDecl *FD, unsigned No);
181
182  /// addBitFieldInfo - Assign a start bit and a size to field FD.
183  void addBitFieldInfo(const FieldDecl *FD, unsigned Begin, unsigned Size);
184
185  /// getBitFieldInfo - Return the BitFieldInfo  that corresponds to the field
186  /// FD.
187  BitFieldInfo getBitFieldInfo(const FieldDecl *FD);
188
189  /// ConvertTagDeclType - Lay out a tagged decl type like struct or union or
190  /// enum.
191  const llvm::Type *ConvertTagDeclType(const TagDecl *TD);
192
193  /// GetExpandedTypes - Expand the type \arg Ty into the LLVM
194  /// argument types it would be passed as on the provided vector \arg
195  /// ArgTys. See ABIArgInfo::Expand.
196  void GetExpandedTypes(QualType Ty, std::vector<const llvm::Type*> &ArgTys);
197};
198
199}  // end namespace CodeGen
200}  // end namespace clang
201
202#endif
203