1//===--- CodeGenTypes.h - Type translation for LLVM CodeGen -----*- 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// This is the code that handles AST -> LLVM type lowering.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H
14#define LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H
15
16#include "CGCall.h"
17#include "clang/Basic/ABI.h"
18#include "clang/CodeGen/CGFunctionInfo.h"
19#include "llvm/ADT/DenseMap.h"
20#include "llvm/IR/Module.h"
21
22namespace llvm {
23class FunctionType;
24class DataLayout;
25class Type;
26class LLVMContext;
27class StructType;
28}
29
30namespace clang {
31class ASTContext;
32template <typename> class CanQual;
33class CXXConstructorDecl;
34class CXXMethodDecl;
35class CodeGenOptions;
36class FunctionProtoType;
37class QualType;
38class RecordDecl;
39class TagDecl;
40class TargetInfo;
41class Type;
42typedef CanQual<Type> CanQualType;
43class GlobalDecl;
44
45namespace CodeGen {
46class ABIInfo;
47class CGCXXABI;
48class CGRecordLayout;
49class CodeGenModule;
50class RequiredArgs;
51
52/// This class organizes the cross-module state that is used while lowering
53/// AST types to LLVM types.
54class CodeGenTypes {
55 CodeGenModule &CGM;
56 // Some of this stuff should probably be left on the CGM.
57 ASTContext &Context;
58 llvm::Module &TheModule;
59 const TargetInfo &Target;
60 CGCXXABI &TheCXXABI;
61
62 // This should not be moved earlier, since its initialization depends on some
63 // of the previous reference members being already initialized
64 const ABIInfo &TheABIInfo;
65
66 /// The opaque type map for Objective-C interfaces. All direct
67 /// manipulation is done by the runtime interfaces, which are
68 /// responsible for coercing to the appropriate type; these opaque
69 /// types are never refined.
70 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes;
71
72 /// Maps clang struct type with corresponding record layout info.
73 llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts;
74
75 /// Contains the LLVM IR type for any converted RecordDecl.
76 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes;
77
78 /// Hold memoized CGFunctionInfo results.
79 llvm::FoldingSet<CGFunctionInfo> FunctionInfos{FunctionInfosLog2InitSize};
80
81 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed;
82
83 /// True if we didn't layout a function due to a being inside
84 /// a recursive struct conversion, set this to true.
85 bool SkippedLayout;
86
87 /// True if any instance of long double types are used.
88 bool LongDoubleReferenced;
89
90 /// This map keeps cache of llvm::Types and maps clang::Type to
91 /// corresponding llvm::Type.
92 llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
93
94 llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers;
95
96 static constexpr unsigned FunctionInfosLog2InitSize = 9;
97 /// Helper for ConvertType.
98 llvm::Type *ConvertFunctionTypeInternal(QualType FT);
99
100public:
101 CodeGenTypes(CodeGenModule &cgm);
102 ~CodeGenTypes();
103
104 const llvm::DataLayout &getDataLayout() const {
105 return TheModule.getDataLayout();
106 }
107 CodeGenModule &getCGM() const { return CGM; }
108 ASTContext &getContext() const { return Context; }
109 const ABIInfo &getABIInfo() const { return TheABIInfo; }
110 const TargetInfo &getTarget() const { return Target; }
111 CGCXXABI &getCXXABI() const { return TheCXXABI; }
112 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
113 const CodeGenOptions &getCodeGenOpts() const;
114
115 /// Convert clang calling convention to LLVM callilng convention.
116 unsigned ClangCallConvToLLVMCallConv(CallingConv CC);
117
118 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR
119 /// qualification.
120 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD);
121
122 /// ConvertType - Convert type T into a llvm::Type.
123 llvm::Type *ConvertType(QualType T);
124
125 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
126 /// ConvertType in that it is used to convert to the memory representation for
127 /// a type. For example, the scalar representation for _Bool is i1, but the
128 /// memory representation is usually i8 or i32, depending on the target.
129 llvm::Type *ConvertTypeForMem(QualType T, bool ForBitField = false);
130
131 /// GetFunctionType - Get the LLVM function type for \arg Info.
132 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
133
134 llvm::FunctionType *GetFunctionType(GlobalDecl GD);
135
136 /// isFuncTypeConvertible - 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 bool isFuncTypeConvertible(const FunctionType *FT);
140 bool isFuncParamTypeConvertible(QualType Ty);
141
142 /// Determine if a C++ inheriting constructor should have parameters matching
143 /// those of its inherited constructor.
144 bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
145 CXXCtorType Type);
146
147 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
148 /// given a CXXMethodDecl. If the method to has an incomplete return type,
149 /// and/or incomplete argument types, this will return the opaque type.
150 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
151
152 const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
153
154 /// UpdateCompletedType - When we find the full definition for a TagDecl,
155 /// replace the 'opaque' type we previously made for it if applicable.
156 void UpdateCompletedType(const TagDecl *TD);
157
158 /// Remove stale types from the type cache when an inheritance model
159 /// gets assigned to a class.
160 void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
161
162 // The arrangement methods are split into three families:
163 // - those meant to drive the signature and prologue/epilogue
164 // of a function declaration or definition,
165 // - those meant for the computation of the LLVM type for an abstract
166 // appearance of a function, and
167 // - those meant for performing the IR-generation of a call.
168 // They differ mainly in how they deal with optional (i.e. variadic)
169 // arguments, as well as unprototyped functions.
170 //
171 // Key points:
172 // - The CGFunctionInfo for emitting a specific call site must include
173 // entries for the optional arguments.
174 // - The function type used at the call site must reflect the formal
175 // signature of the declaration being called, or else the call will
176 // go awry.
177 // - For the most part, unprototyped functions are called by casting to
178 // a formal signature inferred from the specific argument types used
179 // at the call-site. However, some targets (e.g. x86-64) screw with
180 // this for compatibility reasons.
181
182 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
183
184 /// Given a function info for a declaration, return the function info
185 /// for a call with the given arguments.
186 ///
187 /// Often this will be able to simply return the declaration info.
188 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
189 const CallArgList &args);
190
191 /// Free functions are functions that are compatible with an ordinary
192 /// C function pointer type.
193 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
194 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args,
195 const FunctionType *Ty,
196 bool ChainCall);
197 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty);
198 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty);
199
200 /// A nullary function is a freestanding function of type 'void ()'.
201 /// This method works for both calls and declarations.
202 const CGFunctionInfo &arrangeNullaryFunction();
203
204 /// A builtin function is a freestanding function using the default
205 /// C conventions.
206 const CGFunctionInfo &
207 arrangeBuiltinFunctionDeclaration(QualType resultType,
208 const FunctionArgList &args);
209 const CGFunctionInfo &
210 arrangeBuiltinFunctionDeclaration(CanQualType resultType,
211 ArrayRef<CanQualType> argTypes);
212 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
213 const CallArgList &args);
214
215 /// Objective-C methods are C functions with some implicit parameters.
216 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
217 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
218 QualType receiverType);
219 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
220 QualType returnType,
221 const CallArgList &args);
222
223 /// Block invocation functions are C functions with an implicit parameter.
224 const CGFunctionInfo &arrangeBlockFunctionDeclaration(
225 const FunctionProtoType *type,
226 const FunctionArgList &args);
227 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
228 const FunctionType *type);
229
230 /// C++ methods have some special rules and also have implicit parameters.
231 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
232 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD);
233 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
234 const CXXConstructorDecl *D,
235 CXXCtorType CtorKind,
236 unsigned ExtraPrefixArgs,
237 unsigned ExtraSuffixArgs,
238 bool PassProtoArgs = true);
239
240 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
241 const FunctionProtoType *type,
242 RequiredArgs required,
243 unsigned numPrefixArgs);
244 const CGFunctionInfo &
245 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD);
246 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
247 CXXCtorType CT);
248 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD,
249 const FunctionProtoType *FTP,
250 const CXXMethodDecl *MD);
251
252 /// "Arrange" the LLVM information for a call or type with the given
253 /// signature. This is largely an internal method; other clients
254 /// should use one of the above routines, which ultimately defer to
255 /// this.
256 ///
257 /// \param argTypes - must all actually be canonical as params
258 const CGFunctionInfo &arrangeLLVMFunctionInfo(
259 CanQualType returnType, FnInfoOpts opts, ArrayRef<CanQualType> argTypes,
260 FunctionType::ExtInfo info,
261 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos,
262 RequiredArgs args);
263
264 /// Compute a new LLVM record layout object for the given record.
265 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D,
266 llvm::StructType *Ty);
267
268 /// addRecordTypeName - Compute a name from the given record decl with an
269 /// optional suffix and name the given LLVM type using it.
270 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
271 StringRef suffix);
272
273
274public: // These are internal details of CGT that shouldn't be used externally.
275 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
276 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
277
278 /// getExpandedTypes - Expand the type \arg Ty into the LLVM
279 /// argument types it would be passed as. See ABIArgInfo::Expand.
280 void getExpandedTypes(QualType Ty,
281 SmallVectorImpl<llvm::Type *>::iterator &TI);
282
283 /// IsZeroInitializable - Return whether a type can be
284 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
285 bool isZeroInitializable(QualType T);
286
287 /// Check if the pointer type can be zero-initialized (in the C++ sense)
288 /// with an LLVM zeroinitializer.
289 bool isPointerZeroInitializable(QualType T);
290
291 /// IsZeroInitializable - Return whether a record type can be
292 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
293 bool isZeroInitializable(const RecordDecl *RD);
294
295 bool isLongDoubleReferenced() const { return LongDoubleReferenced; }
296 bool isRecordLayoutComplete(const Type *Ty) const;
297 unsigned getTargetAddressSpace(QualType T) const;
298};
299
300} // end namespace CodeGen
301} // end namespace clang
302
303#endif
304

source code of clang/lib/CodeGen/CodeGenTypes.h