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