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CodeGenTypes.h
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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"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/IR/Module.h"
21 
22 namespace llvm {
23 class FunctionType;
24 class DataLayout;
25 class Type;
26 class LLVMContext;
27 class StructType;
28 }
29 
30 namespace clang {
31 class ASTContext;
32 template <typename> class CanQual;
33 class CXXConstructorDecl;
34 class CXXDestructorDecl;
35 class CXXMethodDecl;
36 class CodeGenOptions;
37 class FieldDecl;
38 class FunctionProtoType;
39 class ObjCInterfaceDecl;
40 class ObjCIvarDecl;
41 class PointerType;
42 class QualType;
43 class RecordDecl;
44 class TagDecl;
45 class TargetInfo;
46 class Type;
47 typedef CanQual<Type> CanQualType;
48 class GlobalDecl;
49 
50 namespace CodeGen {
51 class ABIInfo;
52 class CGCXXABI;
53 class CGRecordLayout;
54 class CodeGenModule;
55 class RequiredArgs;
56 
57 /// This class organizes the cross-module state that is used while lowering
58 /// AST types to LLVM types.
59 class 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*, 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 
109 public:
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);
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);
203  const FunctionType *Ty,
204  bool ChainCall);
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);
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);
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,
272  RequiredArgs args);
273 
274  /// Compute a new LLVM record layout object for the given record.
275  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 
284 public: // 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,
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
bool noRecordsBeingLaidOut() const
Definition: CodeGenTypes.h:306
CGCXXABI & getCXXABI() const
Definition: CodeGenTypes.h:119
Represents a function declaration or definition.
Definition: Decl.h:1748
A (possibly-)qualified type.
Definition: Type.h:643
CGRecordLayout - This class handles struct and union layout info while lowering AST types to LLVM typ...
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
const ABIInfo & getABIInfo() const
Definition: CodeGenTypes.h:117
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3387
bool isRecordBeingLaidOut(const Type *Ty) const
Definition: CodeGenTypes.h:309
const llvm::DataLayout & getDataLayout() const
Definition: CodeGenTypes.h:113
The base class of the type hierarchy.
Definition: Type.h:1433
const CGFunctionInfo & arrangeFreeFunctionType(CodeGenModule &CGM, CanQual< FunctionProtoType > Ty)
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2566
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:138
static const CGFunctionInfo & arrangeLLVMFunctionInfo(CodeGenTypes &CGT, bool instanceMethod, SmallVectorImpl< CanQualType > &prefix, CanQual< FunctionProtoType > FTP)
Arrange the LLVM function layout for a value of the given function type, on top of any implicit param...
Definition: CGCall.cpp:175
const CGFunctionInfo & arrangeCXXMethodType(CodeGenModule &CGM, const CXXRecordDecl *RD, const FunctionProtoType *FTP, const CXXMethodDecl *MD)
Represents a struct/union/class.
Definition: Decl.h:3626
Description of a constructor that was inherited from a base class.
Definition: DeclCXX.h:2540
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
Enums/classes describing ABI related information about constructors, destructors and thunks...
const CGFunctionInfo & arrangeObjCMessageSendSignature(CodeGenModule &CGM, const ObjCMethodDecl *MD, QualType receiverType)
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3719
Exposes information about the current target.
Definition: TargetInfo.h:161
A class for recording the number of arguments that a function signature requires. ...
CallingConv
CallingConv - Specifies the calling convention that a function uses.
Definition: Specifiers.h:264
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:40
Represents the declaration of a struct/union/class/enum.
Definition: Decl.h:3097
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:2114
const CGFunctionInfo & arrangeFreeFunctionCall(CodeGenModule &CGM, CanQualType returnType, ArrayRef< CanQualType > argTypes, FunctionType::ExtInfo info, RequiredArgs args)
CanQual< Type > CanQualType
Represents a canonical, potentially-qualified type.
llvm::LLVMContext & getLLVMContext()
Definition: CodeGenTypes.h:120
CXXCtorType
C++ constructor types.
Definition: ABI.h:24
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:358
const TargetInfo & getTarget() const
Definition: CodeGenTypes.h:118
CGFunctionInfo - Class to encapsulate the information about a function definition.
This class organizes the cross-function state that is used while generating LLVM code.
Optional< types::ID > Type
Dataflow Directional Tag Classes.
Implements C++ ABI-specific code generation functions.
Definition: CGCXXABI.h:43
This class organizes the cross-module state that is used while lowering AST types to LLVM types...
Definition: CodeGenTypes.h:59
CodeGenOptions - Track various options which control how the code is optimized and passed to the back...
ASTContext & getContext() const
Definition: CodeGenTypes.h:116
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
ABIInfo - Target specific hooks for defining how a type should be passed or returned from functions...
Definition: ABIInfo.h:50
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:262
A class which abstracts out some details necessary for making a call.
Definition: Type.h:3498