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
61 /// The opaque type map for Objective-C interfaces. All direct
62 /// manipulation is done by the runtime interfaces, which are
63 /// responsible for coercing to the appropriate type; these opaque
64 /// types are never refined.
65 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes;
66
67 /// Maps clang struct type with corresponding record layout info.
68 llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts;
69
70 /// Contains the LLVM IR type for any converted RecordDecl.
71 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes;
72
73 /// Hold memoized CGFunctionInfo results.
74 llvm::FoldingSet<CGFunctionInfo> FunctionInfos{FunctionInfosLog2InitSize};
75
76 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed;
77
78 /// True if we didn't layout a function due to a being inside
79 /// a recursive struct conversion, set this to true.
80 bool SkippedLayout;
81
82 /// True if any instance of long double types are used.
83 bool LongDoubleReferenced;
84
85 /// This map keeps cache of llvm::Types and maps clang::Type to
86 /// corresponding llvm::Type.
87 llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
88
89 llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers;
90
91 static constexpr unsigned FunctionInfosLog2InitSize = 9;
92 /// Helper for ConvertType.
93 llvm::Type *ConvertFunctionTypeInternal(QualType FT);
94
95public:
96 CodeGenTypes(CodeGenModule &cgm);
97 ~CodeGenTypes();
98
99 const llvm::DataLayout &getDataLayout() const {
100 return TheModule.getDataLayout();
101 }
102 CodeGenModule &getCGM() const { return CGM; }
103 ASTContext &getContext() const { return Context; }
104 const TargetInfo &getTarget() const { return Target; }
105 CGCXXABI &getCXXABI() const;
106 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
107 const CodeGenOptions &getCodeGenOpts() const;
108
109 /// Convert clang calling convention to LLVM callilng convention.
110 unsigned ClangCallConvToLLVMCallConv(CallingConv CC);
111
112 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR
113 /// qualification.
114 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD);
115
116 /// ConvertType - Convert type T into a llvm::Type.
117 llvm::Type *ConvertType(QualType T);
118
119 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
120 /// ConvertType in that it is used to convert to the memory representation for
121 /// a type. For example, the scalar representation for _Bool is i1, but the
122 /// memory representation is usually i8 or i32, depending on the target.
123 llvm::Type *ConvertTypeForMem(QualType T);
124
125 /// Check whether the given type needs to be laid out in memory
126 /// using an opaque byte-array type because its load/store type
127 /// does not have the correct alloc size in the LLVM data layout.
128 /// If this is false, the load/store type (convertTypeForLoadStore)
129 /// and memory representation type (ConvertTypeForMem) will
130 /// be the same type.
131 bool typeRequiresSplitIntoByteArray(QualType ASTTy,
132 llvm::Type *LLVMTy = nullptr);
133
134 /// Given that T is a scalar type, return the IR type that should
135 /// be used for load and store operations. For example, this might
136 /// be i8 for _Bool or i96 for _BitInt(65). The store size of the
137 /// load/store type (as reported by LLVM's data layout) is always
138 /// the same as the alloc size of the memory representation type
139 /// returned by ConvertTypeForMem.
140 ///
141 /// As an optimization, if you already know the scalar value type
142 /// for T (as would be returned by ConvertType), you can pass
143 /// it as the second argument so that it does not need to be
144 /// recomputed in common cases where the value type and
145 /// load/store type are the same.
146 llvm::Type *convertTypeForLoadStore(QualType T, llvm::Type *LLVMTy = nullptr);
147
148 /// GetFunctionType - Get the LLVM function type for \arg Info.
149 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
150
151 llvm::FunctionType *GetFunctionType(GlobalDecl GD);
152
153 /// isFuncTypeConvertible - Utility to check whether a function type can
154 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
155 /// type).
156 bool isFuncTypeConvertible(const FunctionType *FT);
157 bool isFuncParamTypeConvertible(QualType Ty);
158
159 /// Determine if a C++ inheriting constructor should have parameters matching
160 /// those of its inherited constructor.
161 bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
162 CXXCtorType Type);
163
164 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
165 /// given a CXXMethodDecl. If the method to has an incomplete return type,
166 /// and/or incomplete argument types, this will return the opaque type.
167 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
168
169 const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
170
171 /// UpdateCompletedType - When we find the full definition for a TagDecl,
172 /// replace the 'opaque' type we previously made for it if applicable.
173 void UpdateCompletedType(const TagDecl *TD);
174
175 /// Remove stale types from the type cache when an inheritance model
176 /// gets assigned to a class.
177 void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
178
179 // The arrangement methods are split into three families:
180 // - those meant to drive the signature and prologue/epilogue
181 // of a function declaration or definition,
182 // - those meant for the computation of the LLVM type for an abstract
183 // appearance of a function, and
184 // - those meant for performing the IR-generation of a call.
185 // They differ mainly in how they deal with optional (i.e. variadic)
186 // arguments, as well as unprototyped functions.
187 //
188 // Key points:
189 // - The CGFunctionInfo for emitting a specific call site must include
190 // entries for the optional arguments.
191 // - The function type used at the call site must reflect the formal
192 // signature of the declaration being called, or else the call will
193 // go awry.
194 // - For the most part, unprototyped functions are called by casting to
195 // a formal signature inferred from the specific argument types used
196 // at the call-site. However, some targets (e.g. x86-64) screw with
197 // this for compatibility reasons.
198
199 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
200
201 /// Given a function info for a declaration, return the function info
202 /// for a call with the given arguments.
203 ///
204 /// Often this will be able to simply return the declaration info.
205 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
206 const CallArgList &args);
207
208 /// Free functions are functions that are compatible with an ordinary
209 /// C function pointer type.
210 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
211 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args,
212 const FunctionType *Ty,
213 bool ChainCall);
214 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty);
215 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty);
216
217 /// A nullary function is a freestanding function of type 'void ()'.
218 /// This method works for both calls and declarations.
219 const CGFunctionInfo &arrangeNullaryFunction();
220
221 /// A builtin function is a freestanding function using the default
222 /// C conventions.
223 const CGFunctionInfo &
224 arrangeBuiltinFunctionDeclaration(QualType resultType,
225 const FunctionArgList &args);
226 const CGFunctionInfo &
227 arrangeBuiltinFunctionDeclaration(CanQualType resultType,
228 ArrayRef<CanQualType> argTypes);
229 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
230 const CallArgList &args);
231
232 /// Objective-C methods are C functions with some implicit parameters.
233 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
234 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
235 QualType receiverType);
236 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
237 QualType returnType,
238 const CallArgList &args);
239
240 /// Block invocation functions are C functions with an implicit parameter.
241 const CGFunctionInfo &arrangeBlockFunctionDeclaration(
242 const FunctionProtoType *type,
243 const FunctionArgList &args);
244 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
245 const FunctionType *type);
246
247 /// C++ methods have some special rules and also have implicit parameters.
248 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
249 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD);
250 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
251 const CXXConstructorDecl *D,
252 CXXCtorType CtorKind,
253 unsigned ExtraPrefixArgs,
254 unsigned ExtraSuffixArgs,
255 bool PassProtoArgs = true);
256
257 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
258 const FunctionProtoType *type,
259 RequiredArgs required,
260 unsigned numPrefixArgs);
261 const CGFunctionInfo &
262 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD);
263 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
264 CXXCtorType CT);
265 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD,
266 const FunctionProtoType *FTP,
267 const CXXMethodDecl *MD);
268
269 /// "Arrange" the LLVM information for a call or type with the given
270 /// signature. This is largely an internal method; other clients
271 /// should use one of the above routines, which ultimately defer to
272 /// this.
273 ///
274 /// \param argTypes - must all actually be canonical as params
275 const CGFunctionInfo &arrangeLLVMFunctionInfo(
276 CanQualType returnType, FnInfoOpts opts, ArrayRef<CanQualType> argTypes,
277 FunctionType::ExtInfo info,
278 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos,
279 RequiredArgs args);
280
281 /// Compute a new LLVM record layout object for the given record.
282 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D,
283 llvm::StructType *Ty);
284
285 /// addRecordTypeName - Compute a name from the given record decl with an
286 /// optional suffix and name the given LLVM type using it.
287 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
288 StringRef suffix);
289
290
291public: // These are internal details of CGT that shouldn't be used externally.
292 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
293 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
294
295 /// getExpandedTypes - Expand the type \arg Ty into the LLVM
296 /// argument types it would be passed as. See ABIArgInfo::Expand.
297 void getExpandedTypes(QualType Ty,
298 SmallVectorImpl<llvm::Type *>::iterator &TI);
299
300 /// IsZeroInitializable - Return whether a type can be
301 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
302 bool isZeroInitializable(QualType T);
303
304 /// Check if the pointer type can be zero-initialized (in the C++ sense)
305 /// with an LLVM zeroinitializer.
306 bool isPointerZeroInitializable(QualType T);
307
308 /// IsZeroInitializable - Return whether a record type can be
309 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
310 bool isZeroInitializable(const RecordDecl *RD);
311
312 bool isLongDoubleReferenced() const { return LongDoubleReferenced; }
313 bool isRecordLayoutComplete(const Type *Ty) const;
314 unsigned getTargetAddressSpace(QualType T) const;
315};
316
317} // end namespace CodeGen
318} // end namespace clang
319
320#endif
321