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 CXXDestructorDecl;
35class CXXMethodDecl;
36class CodeGenOptions;
37class FieldDecl;
38class FunctionProtoType;
39class ObjCInterfaceDecl;
40class ObjCIvarDecl;
41class PointerType;
42class QualType;
43class RecordDecl;
44class TagDecl;
45class TargetInfo;
46class Type;
47typedef CanQual<Type> CanQualType;
48class GlobalDecl;
49
50namespace CodeGen {
51class ABIInfo;
52class CGCXXABI;
53class CGRecordLayout;
54class CodeGenModule;
55class RequiredArgs;
56
57/// This class organizes the cross-module state that is used while lowering
58/// AST types to LLVM types.
59class CodeGenTypes {
60 CodeGenModule &CGM;
61 // Some of this stuff should probably be left on the CGM.
62 ASTContext &Context;
63 llvm::Module &TheModule;
64 const TargetInfo &Target;
65 CGCXXABI &TheCXXABI;
66
67 // This should not be moved earlier, since its initialization depends on some
68 // of the previous reference members being already initialized
69 const ABIInfo &TheABIInfo;
70
71 /// The opaque type map for Objective-C interfaces. All direct
72 /// manipulation is done by the runtime interfaces, which are
73 /// responsible for coercing to the appropriate type; these opaque
74 /// types are never refined.
75 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes;
76
77 /// Maps clang struct type with corresponding record layout info.
78 llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts;
79
80 /// Contains the LLVM IR type for any converted RecordDecl.
81 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes;
82
83 /// Hold memoized CGFunctionInfo results.
84 llvm::FoldingSet<CGFunctionInfo> FunctionInfos;
85
86 /// This set keeps track of records that we're currently converting
87 /// to an IR type. For example, when converting:
88 /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B'
89 /// types will be in this set.
90 llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut;
91
92 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed;
93
94 /// True if we didn't layout a function due to a being inside
95 /// a recursive struct conversion, set this to true.
96 bool SkippedLayout;
97
98 SmallVector<const RecordDecl *, 8> DeferredRecords;
99
100 /// This map keeps cache of llvm::Types and maps clang::Type to
101 /// corresponding llvm::Type.
102 llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
103
104 llvm::SmallSet<const Type *, 8> RecordsWithOpaqueMemberPointers;
105
106 /// Helper for ConvertType.
107 llvm::Type *ConvertFunctionTypeInternal(QualType FT);
108
109public:
110 CodeGenTypes(CodeGenModule &cgm);
111 ~CodeGenTypes();
112
113 const llvm::DataLayout &getDataLayout() const {
114 return TheModule.getDataLayout();
115 }
116 ASTContext &getContext() const { return Context; }
117 const ABIInfo &getABIInfo() const { return TheABIInfo; }
118 const TargetInfo &getTarget() const { return Target; }
119 CGCXXABI &getCXXABI() const { return TheCXXABI; }
120 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
121 const CodeGenOptions &getCodeGenOpts() const;
122
123 /// Convert clang calling convention to LLVM callilng convention.
124 unsigned ClangCallConvToLLVMCallConv(CallingConv CC);
125
126 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR
127 /// qualification.
128 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD);
129
130 /// ConvertType - Convert type T into a llvm::Type.
131 llvm::Type *ConvertType(QualType T);
132
133 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
134 /// ConvertType in that it is used to convert to the memory representation for
135 /// a type. For example, the scalar representation for _Bool is i1, but the
136 /// memory representation is usually i8 or i32, depending on the target.
137 llvm::Type *ConvertTypeForMem(QualType T, bool ForBitField = false);
138
139 /// GetFunctionType - Get the LLVM function type for \arg Info.
140 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
141
142 llvm::FunctionType *GetFunctionType(GlobalDecl GD);
143
144 /// isFuncTypeConvertible - Utility to check whether a function type can
145 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
146 /// type).
147 bool isFuncTypeConvertible(const FunctionType *FT);
148 bool isFuncParamTypeConvertible(QualType Ty);
149
150 /// Determine if a C++ inheriting constructor should have parameters matching
151 /// those of its inherited constructor.
152 bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
153 CXXCtorType Type);
154
155 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
156 /// given a CXXMethodDecl. If the method to has an incomplete return type,
157 /// and/or incomplete argument types, this will return the opaque type.
158 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
159
160 const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
161
162 /// UpdateCompletedType - When we find the full definition for a TagDecl,
163 /// replace the 'opaque' type we previously made for it if applicable.
164 void UpdateCompletedType(const TagDecl *TD);
165
166 /// Remove stale types from the type cache when an inheritance model
167 /// gets assigned to a class.
168 void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
169
170 // The arrangement methods are split into three families:
171 // - those meant to drive the signature and prologue/epilogue
172 // of a function declaration or definition,
173 // - those meant for the computation of the LLVM type for an abstract
174 // appearance of a function, and
175 // - those meant for performing the IR-generation of a call.
176 // They differ mainly in how they deal with optional (i.e. variadic)
177 // arguments, as well as unprototyped functions.
178 //
179 // Key points:
180 // - The CGFunctionInfo for emitting a specific call site must include
181 // entries for the optional arguments.
182 // - The function type used at the call site must reflect the formal
183 // signature of the declaration being called, or else the call will
184 // go awry.
185 // - For the most part, unprototyped functions are called by casting to
186 // a formal signature inferred from the specific argument types used
187 // at the call-site. However, some targets (e.g. x86-64) screw with
188 // this for compatibility reasons.
189
190 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
191
192 /// Given a function info for a declaration, return the function info
193 /// for a call with the given arguments.
194 ///
195 /// Often this will be able to simply return the declaration info.
196 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
197 const CallArgList &args);
198
199 /// Free functions are functions that are compatible with an ordinary
200 /// C function pointer type.
201 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
202 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args,
203 const FunctionType *Ty,
204 bool ChainCall);
205 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty);
206 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty);
207
208 /// A nullary function is a freestanding function of type 'void ()'.
209 /// This method works for both calls and declarations.
210 const CGFunctionInfo &arrangeNullaryFunction();
211
212 /// A builtin function is a freestanding function using the default
213 /// C conventions.
214 const CGFunctionInfo &
215 arrangeBuiltinFunctionDeclaration(QualType resultType,
216 const FunctionArgList &args);
217 const CGFunctionInfo &
218 arrangeBuiltinFunctionDeclaration(CanQualType resultType,
219 ArrayRef<CanQualType> argTypes);
220 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
221 const CallArgList &args);
222
223 /// Objective-C methods are C functions with some implicit parameters.
224 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
225 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
226 QualType receiverType);
227 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
228 QualType returnType,
229 const CallArgList &args);
230
231 /// Block invocation functions are C functions with an implicit parameter.
232 const CGFunctionInfo &arrangeBlockFunctionDeclaration(
233 const FunctionProtoType *type,
234 const FunctionArgList &args);
235 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
236 const FunctionType *type);
237
238 /// C++ methods have some special rules and also have implicit parameters.
239 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
240 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD);
241 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
242 const CXXConstructorDecl *D,
243 CXXCtorType CtorKind,
244 unsigned ExtraPrefixArgs,
245 unsigned ExtraSuffixArgs,
246 bool PassProtoArgs = true);
247
248 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
249 const FunctionProtoType *type,
250 RequiredArgs required,
251 unsigned numPrefixArgs);
252 const CGFunctionInfo &
253 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD);
254 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
255 CXXCtorType CT);
256 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD,
257 const FunctionProtoType *FTP,
258 const CXXMethodDecl *MD);
259
260 /// "Arrange" the LLVM information for a call or type with the given
261 /// signature. This is largely an internal method; other clients
262 /// should use one of the above routines, which ultimately defer to
263 /// this.
264 ///
265 /// \param argTypes - must all actually be canonical as params
266 const CGFunctionInfo &arrangeLLVMFunctionInfo(CanQualType returnType,
267 bool instanceMethod,
268 bool chainCall,
269 ArrayRef<CanQualType> argTypes,
270 FunctionType::ExtInfo info,
271 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos,
272 RequiredArgs args);
273
274 /// Compute a new LLVM record layout object for the given record.
275 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D,
276 llvm::StructType *Ty);
277
278 /// addRecordTypeName - Compute a name from the given record decl with an
279 /// optional suffix and name the given LLVM type using it.
280 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
281 StringRef suffix);
282
283
284public: // These are internal details of CGT that shouldn't be used externally.
285 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
286 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
287
288 /// getExpandedTypes - Expand the type \arg Ty into the LLVM
289 /// argument types it would be passed as. See ABIArgInfo::Expand.
290 void getExpandedTypes(QualType Ty,
291 SmallVectorImpl<llvm::Type *>::iterator &TI);
292
293 /// IsZeroInitializable - Return whether a type can be
294 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
295 bool isZeroInitializable(QualType T);
296
297 /// Check if the pointer type can be zero-initialized (in the C++ sense)
298 /// with an LLVM zeroinitializer.
299 bool isPointerZeroInitializable(QualType T);
300
301 /// IsZeroInitializable - Return whether a record type can be
302 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
303 bool isZeroInitializable(const RecordDecl *RD);
304
305 bool isRecordLayoutComplete(const Type *Ty) const;
306 bool noRecordsBeingLaidOut() const {
307 return RecordsBeingLaidOut.empty();
308 }
309 bool isRecordBeingLaidOut(const Type *Ty) const {
310 return RecordsBeingLaidOut.count(Ty);
311 }
312
313};
314
315} // end namespace CodeGen
316} // end namespace clang
317
318#endif
319