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);
130
131 /// Check whether the given type needs to be laid out in memory
132 /// using an opaque byte-array type because its load/store type
133 /// does not have the correct alloc size in the LLVM data layout.
134 /// If this is false, the load/store type (convertTypeForLoadStore)
135 /// and memory representation type (ConvertTypeForMem) will
136 /// be the same type.
137 bool typeRequiresSplitIntoByteArray(QualType ASTTy,
138 llvm::Type *LLVMTy = nullptr);
139
140 /// Given that T is a scalar type, return the IR type that should
141 /// be used for load and store operations. For example, this might
142 /// be i8 for _Bool or i96 for _BitInt(65). The store size of the
143 /// load/store type (as reported by LLVM's data layout) is always
144 /// the same as the alloc size of the memory representation type
145 /// returned by ConvertTypeForMem.
146 ///
147 /// As an optimization, if you already know the scalar value type
148 /// for T (as would be returned by ConvertType), you can pass
149 /// it as the second argument so that it does not need to be
150 /// recomputed in common cases where the value type and
151 /// load/store type are the same.
152 llvm::Type *convertTypeForLoadStore(QualType T, llvm::Type *LLVMTy = nullptr);
153
154 /// GetFunctionType - Get the LLVM function type for \arg Info.
155 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
156
157 llvm::FunctionType *GetFunctionType(GlobalDecl GD);
158
159 /// isFuncTypeConvertible - Utility to check whether a function type can
160 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
161 /// type).
162 bool isFuncTypeConvertible(const FunctionType *FT);
163 bool isFuncParamTypeConvertible(QualType Ty);
164
165 /// Determine if a C++ inheriting constructor should have parameters matching
166 /// those of its inherited constructor.
167 bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
168 CXXCtorType Type);
169
170 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
171 /// given a CXXMethodDecl. If the method to has an incomplete return type,
172 /// and/or incomplete argument types, this will return the opaque type.
173 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
174
175 const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
176
177 /// UpdateCompletedType - When we find the full definition for a TagDecl,
178 /// replace the 'opaque' type we previously made for it if applicable.
179 void UpdateCompletedType(const TagDecl *TD);
180
181 /// Remove stale types from the type cache when an inheritance model
182 /// gets assigned to a class.
183 void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
184
185 // The arrangement methods are split into three families:
186 // - those meant to drive the signature and prologue/epilogue
187 // of a function declaration or definition,
188 // - those meant for the computation of the LLVM type for an abstract
189 // appearance of a function, and
190 // - those meant for performing the IR-generation of a call.
191 // They differ mainly in how they deal with optional (i.e. variadic)
192 // arguments, as well as unprototyped functions.
193 //
194 // Key points:
195 // - The CGFunctionInfo for emitting a specific call site must include
196 // entries for the optional arguments.
197 // - The function type used at the call site must reflect the formal
198 // signature of the declaration being called, or else the call will
199 // go awry.
200 // - For the most part, unprototyped functions are called by casting to
201 // a formal signature inferred from the specific argument types used
202 // at the call-site. However, some targets (e.g. x86-64) screw with
203 // this for compatibility reasons.
204
205 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
206
207 /// Given a function info for a declaration, return the function info
208 /// for a call with the given arguments.
209 ///
210 /// Often this will be able to simply return the declaration info.
211 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
212 const CallArgList &args);
213
214 /// Free functions are functions that are compatible with an ordinary
215 /// C function pointer type.
216 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
217 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args,
218 const FunctionType *Ty,
219 bool ChainCall);
220 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty);
221 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty);
222
223 /// A nullary function is a freestanding function of type 'void ()'.
224 /// This method works for both calls and declarations.
225 const CGFunctionInfo &arrangeNullaryFunction();
226
227 /// A builtin function is a freestanding function using the default
228 /// C conventions.
229 const CGFunctionInfo &
230 arrangeBuiltinFunctionDeclaration(QualType resultType,
231 const FunctionArgList &args);
232 const CGFunctionInfo &
233 arrangeBuiltinFunctionDeclaration(CanQualType resultType,
234 ArrayRef<CanQualType> argTypes);
235 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
236 const CallArgList &args);
237
238 /// Objective-C methods are C functions with some implicit parameters.
239 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
240 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
241 QualType receiverType);
242 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
243 QualType returnType,
244 const CallArgList &args);
245
246 /// Block invocation functions are C functions with an implicit parameter.
247 const CGFunctionInfo &arrangeBlockFunctionDeclaration(
248 const FunctionProtoType *type,
249 const FunctionArgList &args);
250 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
251 const FunctionType *type);
252
253 /// C++ methods have some special rules and also have implicit parameters.
254 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
255 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD);
256 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
257 const CXXConstructorDecl *D,
258 CXXCtorType CtorKind,
259 unsigned ExtraPrefixArgs,
260 unsigned ExtraSuffixArgs,
261 bool PassProtoArgs = true);
262
263 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
264 const FunctionProtoType *type,
265 RequiredArgs required,
266 unsigned numPrefixArgs);
267 const CGFunctionInfo &
268 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD);
269 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
270 CXXCtorType CT);
271 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD,
272 const FunctionProtoType *FTP,
273 const CXXMethodDecl *MD);
274
275 /// "Arrange" the LLVM information for a call or type with the given
276 /// signature. This is largely an internal method; other clients
277 /// should use one of the above routines, which ultimately defer to
278 /// this.
279 ///
280 /// \param argTypes - must all actually be canonical as params
281 const CGFunctionInfo &arrangeLLVMFunctionInfo(
282 CanQualType returnType, FnInfoOpts opts, ArrayRef<CanQualType> argTypes,
283 FunctionType::ExtInfo info,
284 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos,
285 RequiredArgs args);
286
287 /// Compute a new LLVM record layout object for the given record.
288 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D,
289 llvm::StructType *Ty);
290
291 /// addRecordTypeName - Compute a name from the given record decl with an
292 /// optional suffix and name the given LLVM type using it.
293 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
294 StringRef suffix);
295
296
297public: // These are internal details of CGT that shouldn't be used externally.
298 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
299 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
300
301 /// getExpandedTypes - Expand the type \arg Ty into the LLVM
302 /// argument types it would be passed as. See ABIArgInfo::Expand.
303 void getExpandedTypes(QualType Ty,
304 SmallVectorImpl<llvm::Type *>::iterator &TI);
305
306 /// IsZeroInitializable - Return whether a type can be
307 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
308 bool isZeroInitializable(QualType T);
309
310 /// Check if the pointer type can be zero-initialized (in the C++ sense)
311 /// with an LLVM zeroinitializer.
312 bool isPointerZeroInitializable(QualType T);
313
314 /// IsZeroInitializable - Return whether a record type can be
315 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
316 bool isZeroInitializable(const RecordDecl *RD);
317
318 bool isLongDoubleReferenced() const { return LongDoubleReferenced; }
319 bool isRecordLayoutComplete(const Type *Ty) const;
320 unsigned getTargetAddressSpace(QualType T) const;
321};
322
323} // end namespace CodeGen
324} // end namespace clang
325
326#endif
327