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 "CGCall.h"
18 #include "GlobalDecl.h"
19 #include "llvm/Module.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include <vector>
22 
23 namespace llvm {
24   class FunctionType;
25   class Module;
26   class OpaqueType;
27   class PATypeHolder;
28   class TargetData;
29   class Type;
30   class LLVMContext;
31 }
32 
33 namespace clang {
34   class ABIInfo;
35   class ASTContext;
36   template <typename> class CanQual;
37   class CXXConstructorDecl;
38   class CXXDestructorDecl;
39   class CXXMethodDecl;
40   class FieldDecl;
41   class FunctionProtoType;
42   class ObjCInterfaceDecl;
43   class ObjCIvarDecl;
44   class PointerType;
45   class QualType;
46   class RecordDecl;
47   class TagDecl;
48   class TargetInfo;
49   class Type;
50   typedef CanQual<Type> CanQualType;
51 
52 namespace CodeGen {
53   class CGCXXABI;
54   class CGRecordLayout;
55 
56 /// CodeGenTypes - This class organizes the cross-module state that is used
57 /// while lowering AST types to LLVM types.
58 class CodeGenTypes {
59   ASTContext &Context;
60   const TargetInfo &Target;
61   llvm::Module& TheModule;
62   const llvm::TargetData& TheTargetData;
63   const ABIInfo& TheABIInfo;
64   CGCXXABI &TheCXXABI;
65 
66   llvm::SmallVector<std::pair<QualType,
67                               llvm::OpaqueType *>, 8>  PointersToResolve;
68 
69   llvm::DenseMap<const Type*, llvm::PATypeHolder> TagDeclTypes;
70 
71   llvm::DenseMap<const Type*, llvm::PATypeHolder> FunctionTypes;
72 
73   /// The opaque type map for Objective-C interfaces. All direct
74   /// manipulation is done by the runtime interfaces, which are
75   /// responsible for coercing to the appropriate type; these opaque
76   /// types are never refined.
77   llvm::DenseMap<const ObjCInterfaceType*, const llvm::Type *> InterfaceTypes;
78 
79   /// CGRecordLayouts - This maps llvm struct type with corresponding
80   /// record layout info.
81   llvm::DenseMap<const Type*, CGRecordLayout *> CGRecordLayouts;
82 
83   /// FunctionInfos - Hold memoized CGFunctionInfo results.
84   llvm::FoldingSet<CGFunctionInfo> FunctionInfos;
85 
86 private:
87   /// TypeCache - This map keeps cache of llvm::Types (through PATypeHolder)
88   /// and maps llvm::Types to corresponding clang::Type. llvm::PATypeHolder is
89   /// used instead of llvm::Type because it allows us to bypass potential
90   /// dangling type pointers due to type refinement on llvm side.
91   llvm::DenseMap<const Type *, llvm::PATypeHolder> TypeCache;
92 
93   /// ConvertNewType - Convert type T into a llvm::Type. Do not use this
94   /// method directly because it does not do any type caching. This method
95   /// is available only for ConvertType(). CovertType() is preferred
96   /// interface to convert type T into a llvm::Type.
97   const llvm::Type *ConvertNewType(QualType T);
98 
99   /// HandleLateResolvedPointers - For top-level ConvertType calls, this handles
100   /// pointers that are referenced but have not been converted yet.  This is
101   /// used to handle cyclic structures properly.
102   void HandleLateResolvedPointers();
103 
104 public:
105   CodeGenTypes(ASTContext &Ctx, llvm::Module &M, const llvm::TargetData &TD,
106                const ABIInfo &Info, CGCXXABI &CXXABI);
107   ~CodeGenTypes();
108 
109   const llvm::TargetData &getTargetData() const { return TheTargetData; }
110   const TargetInfo &getTarget() const { return Target; }
111   ASTContext &getContext() const { return Context; }
112   const ABIInfo &getABIInfo() const { return TheABIInfo; }
113   CGCXXABI &getCXXABI() const { return TheCXXABI; }
114   llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
115 
116   /// ConvertType - Convert type T into a llvm::Type.
117   const llvm::Type *ConvertType(QualType T, bool IsRecursive = false);
118   const llvm::Type *ConvertTypeRecursive(QualType T);
119 
120   /// ConvertTypeForMem - Convert type T into a llvm::Type.  This differs from
121   /// ConvertType in that it is used to convert to the memory representation for
122   /// a type.  For example, the scalar representation for _Bool is i1, but the
123   /// memory representation is usually i8 or i32, depending on the target.
124   const llvm::Type *ConvertTypeForMem(QualType T, bool IsRecursive = false);
125   const llvm::Type *ConvertTypeForMemRecursive(QualType T) {
126     return ConvertTypeForMem(T, true);
127   }
128 
129   /// GetFunctionType - Get the LLVM function type for \arg Info.
130   const llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info,
131                                             bool IsVariadic,
132                                             bool IsRecursive = false);
133 
134   const llvm::FunctionType *GetFunctionType(GlobalDecl GD);
135 
136   /// VerifyFuncTypeComplete - Utility to check whether a function type can
137   /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
138   /// type).
139   static const TagType *VerifyFuncTypeComplete(const Type* T);
140 
141   /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
142   /// given a CXXMethodDecl. If the method to has an incomplete return type,
143   /// and/or incomplete argument types, this will return the opaque type.
144   const llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
145 
146   const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
147 
148   /// UpdateCompletedType - When we find the full definition for a TagDecl,
149   /// replace the 'opaque' type we previously made for it if applicable.
150   void UpdateCompletedType(const TagDecl *TD);
151 
152   /// getFunctionInfo - Get the function info for the specified function decl.
153   const CGFunctionInfo &getFunctionInfo(GlobalDecl GD);
154 
155   const CGFunctionInfo &getFunctionInfo(const FunctionDecl *FD);
156   const CGFunctionInfo &getFunctionInfo(const CXXMethodDecl *MD);
157   const CGFunctionInfo &getFunctionInfo(const ObjCMethodDecl *MD);
158   const CGFunctionInfo &getFunctionInfo(const CXXConstructorDecl *D,
159                                         CXXCtorType Type);
160   const CGFunctionInfo &getFunctionInfo(const CXXDestructorDecl *D,
161                                         CXXDtorType Type);
162 
163   const CGFunctionInfo &getFunctionInfo(const CallArgList &Args,
164                                         const FunctionType *Ty) {
165     return getFunctionInfo(Ty->getResultType(), Args,
166                            Ty->getExtInfo());
167   }
168 
169   const CGFunctionInfo &getFunctionInfo(CanQual<FunctionProtoType> Ty,
170                                         bool IsRecursive = false);
171   const CGFunctionInfo &getFunctionInfo(CanQual<FunctionNoProtoType> Ty,
172                                         bool IsRecursive = false);
173 
174   /// getFunctionInfo - Get the function info for a member function of
175   /// the given type.  This is used for calls through member function
176   /// pointers.
177   const CGFunctionInfo &getFunctionInfo(const CXXRecordDecl *RD,
178                                         const FunctionProtoType *FTP);
179 
180   /// getFunctionInfo - Get the function info for a function described by a
181   /// return type and argument types. If the calling convention is not
182   /// specified, the "C" calling convention will be used.
183   const CGFunctionInfo &getFunctionInfo(QualType ResTy,
184                                         const CallArgList &Args,
185                                         const FunctionType::ExtInfo &Info);
186   const CGFunctionInfo &getFunctionInfo(QualType ResTy,
187                                         const FunctionArgList &Args,
188                                         const FunctionType::ExtInfo &Info);
189 
190   /// Retrieves the ABI information for the given function signature.
191   ///
192   /// \param ArgTys - must all actually be canonical as params
193   const CGFunctionInfo &getFunctionInfo(CanQualType RetTy,
194                                const llvm::SmallVectorImpl<CanQualType> &ArgTys,
195                                         const FunctionType::ExtInfo &Info,
196                                         bool IsRecursive = false);
197 
198   /// \brief Compute a new LLVM record layout object for the given record.
199   CGRecordLayout *ComputeRecordLayout(const RecordDecl *D);
200 
201 public:  // These are internal details of CGT that shouldn't be used externally.
202   /// ConvertTagDeclType - Lay out a tagged decl type like struct or union or
203   /// enum.
204   const llvm::Type *ConvertTagDeclType(const TagDecl *TD);
205 
206   /// GetExpandedTypes - Expand the type \arg Ty into the LLVM
207   /// argument types it would be passed as on the provided vector \arg
208   /// ArgTys. See ABIArgInfo::Expand.
209   void GetExpandedTypes(QualType Ty, std::vector<const llvm::Type*> &ArgTys,
210                         bool IsRecursive);
211 
212   /// IsZeroInitializable - Return whether a type can be
213   /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
214   bool isZeroInitializable(QualType T);
215 
216   /// IsZeroInitializable - Return whether a record type can be
217   /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
218   bool isZeroInitializable(const CXXRecordDecl *RD);
219 };
220 
221 }  // end namespace CodeGen
222 }  // end namespace clang
223 
224 #endif
225