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  /// This set keeps track of records that we're currently converting
82  /// to an IR type.  For example, when converting:
83  /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B'
84  /// types will be in this set.
85  llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut;
86
87  llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed;
88
89  /// True if we didn't layout a function due to a being inside
90  /// a recursive struct conversion, set this to true.
91  bool SkippedLayout;
92
93  SmallVector<const RecordDecl *, 8> DeferredRecords;
94
95  /// This map keeps cache of llvm::Types and maps clang::Type to
96  /// corresponding llvm::Type.
97  llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
98
99  llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers;
100
101  static constexpr unsigned FunctionInfosLog2InitSize = 9;
102  /// Helper for ConvertType.
103  llvm::Type *ConvertFunctionTypeInternal(QualType FT);
104
105public:
106  CodeGenTypes(CodeGenModule &cgm);
107  ~CodeGenTypes();
108
109  const llvm::DataLayout &getDataLayout() const {
110    return TheModule.getDataLayout();
111  }
112  CodeGenModule &getCGM() const { return CGM; }
113  ASTContext &getContext() const { return Context; }
114  const ABIInfo &getABIInfo() const { return TheABIInfo; }
115  const TargetInfo &getTarget() const { return Target; }
116  CGCXXABI &getCXXABI() const { return TheCXXABI; }
117  llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
118  const CodeGenOptions &getCodeGenOpts() const;
119
120  /// Convert clang calling convention to LLVM callilng convention.
121  unsigned ClangCallConvToLLVMCallConv(CallingConv CC);
122
123  /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR
124  /// qualification.
125  CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD);
126
127  /// ConvertType - Convert type T into a llvm::Type.
128  llvm::Type *ConvertType(QualType T);
129
130  /// ConvertTypeForMem - Convert type T into a llvm::Type.  This differs from
131  /// ConvertType in that it is used to convert to the memory representation for
132  /// a type.  For example, the scalar representation for _Bool is i1, but the
133  /// memory representation is usually i8 or i32, depending on the target.
134  llvm::Type *ConvertTypeForMem(QualType T, bool ForBitField = false);
135
136  /// GetFunctionType - Get the LLVM function type for \arg Info.
137  llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
138
139  llvm::FunctionType *GetFunctionType(GlobalDecl GD);
140
141  /// isFuncTypeConvertible - Utility to check whether a function type can
142  /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
143  /// type).
144  bool isFuncTypeConvertible(const FunctionType *FT);
145  bool isFuncParamTypeConvertible(QualType Ty);
146
147  /// Determine if a C++ inheriting constructor should have parameters matching
148  /// those of its inherited constructor.
149  bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
150                               CXXCtorType Type);
151
152  /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
153  /// given a CXXMethodDecl. If the method to has an incomplete return type,
154  /// and/or incomplete argument types, this will return the opaque type.
155  llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
156
157  const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
158
159  /// UpdateCompletedType - When we find the full definition for a TagDecl,
160  /// replace the 'opaque' type we previously made for it if applicable.
161  void UpdateCompletedType(const TagDecl *TD);
162
163  /// Remove stale types from the type cache when an inheritance model
164  /// gets assigned to a class.
165  void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
166
167  // The arrangement methods are split into three families:
168  //   - those meant to drive the signature and prologue/epilogue
169  //     of a function declaration or definition,
170  //   - those meant for the computation of the LLVM type for an abstract
171  //     appearance of a function, and
172  //   - those meant for performing the IR-generation of a call.
173  // They differ mainly in how they deal with optional (i.e. variadic)
174  // arguments, as well as unprototyped functions.
175  //
176  // Key points:
177  // - The CGFunctionInfo for emitting a specific call site must include
178  //   entries for the optional arguments.
179  // - The function type used at the call site must reflect the formal
180  //   signature of the declaration being called, or else the call will
181  //   go awry.
182  // - For the most part, unprototyped functions are called by casting to
183  //   a formal signature inferred from the specific argument types used
184  //   at the call-site.  However, some targets (e.g. x86-64) screw with
185  //   this for compatibility reasons.
186
187  const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
188
189  /// Given a function info for a declaration, return the function info
190  /// for a call with the given arguments.
191  ///
192  /// Often this will be able to simply return the declaration info.
193  const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
194                                    const CallArgList &args);
195
196  /// Free functions are functions that are compatible with an ordinary
197  /// C function pointer type.
198  const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
199  const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args,
200                                                const FunctionType *Ty,
201                                                bool ChainCall);
202  const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty);
203  const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty);
204
205  /// A nullary function is a freestanding function of type 'void ()'.
206  /// This method works for both calls and declarations.
207  const CGFunctionInfo &arrangeNullaryFunction();
208
209  /// A builtin function is a freestanding function using the default
210  /// C conventions.
211  const CGFunctionInfo &
212  arrangeBuiltinFunctionDeclaration(QualType resultType,
213                                    const FunctionArgList &args);
214  const CGFunctionInfo &
215  arrangeBuiltinFunctionDeclaration(CanQualType resultType,
216                                    ArrayRef<CanQualType> argTypes);
217  const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
218                                                   const CallArgList &args);
219
220  /// Objective-C methods are C functions with some implicit parameters.
221  const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
222  const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD,
223                                                        QualType receiverType);
224  const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
225                                                     QualType returnType,
226                                                     const CallArgList &args);
227
228  /// Block invocation functions are C functions with an implicit parameter.
229  const CGFunctionInfo &arrangeBlockFunctionDeclaration(
230                                                 const FunctionProtoType *type,
231                                                 const FunctionArgList &args);
232  const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
233                                                 const FunctionType *type);
234
235  /// C++ methods have some special rules and also have implicit parameters.
236  const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
237  const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD);
238  const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
239                                                  const CXXConstructorDecl *D,
240                                                  CXXCtorType CtorKind,
241                                                  unsigned ExtraPrefixArgs,
242                                                  unsigned ExtraSuffixArgs,
243                                                  bool PassProtoArgs = true);
244
245  const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
246                                             const FunctionProtoType *type,
247                                             RequiredArgs required,
248                                             unsigned numPrefixArgs);
249  const CGFunctionInfo &
250  arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD);
251  const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
252                                                 CXXCtorType CT);
253  const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD,
254                                             const FunctionProtoType *FTP,
255                                             const CXXMethodDecl *MD);
256
257  /// "Arrange" the LLVM information for a call or type with the given
258  /// signature.  This is largely an internal method; other clients
259  /// should use one of the above routines, which ultimately defer to
260  /// this.
261  ///
262  /// \param argTypes - must all actually be canonical as params
263  const CGFunctionInfo &arrangeLLVMFunctionInfo(CanQualType returnType,
264                                                bool instanceMethod,
265                                                bool chainCall,
266                                                ArrayRef<CanQualType> argTypes,
267                                                FunctionType::ExtInfo info,
268                    ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos,
269                                                RequiredArgs args);
270
271  /// Compute a new LLVM record layout object for the given record.
272  std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D,
273                                                      llvm::StructType *Ty);
274
275  /// addRecordTypeName - Compute a name from the given record decl with an
276  /// optional suffix and name the given LLVM type using it.
277  void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
278                         StringRef suffix);
279
280
281public:  // These are internal details of CGT that shouldn't be used externally.
282  /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
283  llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
284
285  /// getExpandedTypes - Expand the type \arg Ty into the LLVM
286  /// argument types it would be passed as. See ABIArgInfo::Expand.
287  void getExpandedTypes(QualType Ty,
288                        SmallVectorImpl<llvm::Type *>::iterator &TI);
289
290  /// IsZeroInitializable - Return whether a type can be
291  /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
292  bool isZeroInitializable(QualType T);
293
294  /// Check if the pointer type can be zero-initialized (in the C++ sense)
295  /// with an LLVM zeroinitializer.
296  bool isPointerZeroInitializable(QualType T);
297
298  /// IsZeroInitializable - Return whether a record type can be
299  /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
300  bool isZeroInitializable(const RecordDecl *RD);
301
302  bool isRecordLayoutComplete(const Type *Ty) const;
303  bool noRecordsBeingLaidOut() const {
304    return RecordsBeingLaidOut.empty();
305  }
306  bool isRecordBeingLaidOut(const Type *Ty) const {
307    return RecordsBeingLaidOut.count(Ty);
308  }
309  unsigned getTargetAddressSpace(QualType T) const;
310};
311
312}  // end namespace CodeGen
313}  // end namespace clang
314
315#endif
316