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CodeGenTypes.h
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1 //===--- CodeGenTypes.h - Type translation for LLVM CodeGen -----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This is the code that handles AST -> LLVM type lowering.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H
15 #define LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H
16 
17 #include "CGCall.h"
18 #include "clang/Basic/ABI.h"
20 #include "clang/Sema/Sema.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/IR/Module.h"
23 
24 namespace llvm {
25 class FunctionType;
26 class DataLayout;
27 class Type;
28 class LLVMContext;
29 class StructType;
30 }
31 
32 namespace clang {
33 class ASTContext;
34 template <typename> class CanQual;
35 class CXXConstructorDecl;
36 class CXXDestructorDecl;
37 class CXXMethodDecl;
38 class CodeGenOptions;
39 class FieldDecl;
40 class FunctionProtoType;
41 class ObjCInterfaceDecl;
42 class ObjCIvarDecl;
43 class PointerType;
44 class QualType;
45 class RecordDecl;
46 class TagDecl;
47 class TargetInfo;
48 class Type;
49 typedef CanQual<Type> CanQualType;
50 class GlobalDecl;
51 
52 namespace CodeGen {
53 class ABIInfo;
54 class CGCXXABI;
55 class CGRecordLayout;
56 class CodeGenModule;
57 class RequiredArgs;
58 
59 enum class StructorType {
60  Complete, // constructor or destructor
61  Base, // constructor or destructor
62  Deleting // destructor only
63 };
64 
66  switch (T) {
67  case StructorType::Complete:
68  return Ctor_Complete;
69  case StructorType::Base:
70  return Ctor_Base;
71  case StructorType::Deleting:
72  llvm_unreachable("cannot have a deleting ctor");
73  }
74  llvm_unreachable("not a StructorType");
75 }
76 
78  switch (T) {
79  case Ctor_Complete:
80  return StructorType::Complete;
81  case Ctor_Base:
82  return StructorType::Base;
83  case Ctor_Comdat:
84  llvm_unreachable("not expecting a COMDAT");
87  llvm_unreachable("not expecting a closure");
88  }
89  llvm_unreachable("not a CXXCtorType");
90 }
91 
93  switch (T) {
94  case StructorType::Complete:
95  return Dtor_Complete;
96  case StructorType::Base:
97  return Dtor_Base;
98  case StructorType::Deleting:
99  return Dtor_Deleting;
100  }
101  llvm_unreachable("not a StructorType");
102 }
103 
105  switch (T) {
106  case Dtor_Deleting:
107  return StructorType::Deleting;
108  case Dtor_Complete:
109  return StructorType::Complete;
110  case Dtor_Base:
111  return StructorType::Base;
112  case Dtor_Comdat:
113  llvm_unreachable("not expecting a COMDAT");
114  }
115  llvm_unreachable("not a CXXDtorType");
116 }
117 
118 /// This class organizes the cross-module state that is used while lowering
119 /// AST types to LLVM types.
121  CodeGenModule &CGM;
122  // Some of this stuff should probably be left on the CGM.
123  ASTContext &Context;
124  llvm::Module &TheModule;
125  const TargetInfo &Target;
126  CGCXXABI &TheCXXABI;
127 
128  // This should not be moved earlier, since its initialization depends on some
129  // of the previous reference members being already initialized
130  const ABIInfo &TheABIInfo;
131 
132  /// The opaque type map for Objective-C interfaces. All direct
133  /// manipulation is done by the runtime interfaces, which are
134  /// responsible for coercing to the appropriate type; these opaque
135  /// types are never refined.
136  llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes;
137 
138  /// Maps clang struct type with corresponding record layout info.
139  llvm::DenseMap<const Type*, CGRecordLayout *> CGRecordLayouts;
140 
141  /// Contains the LLVM IR type for any converted RecordDecl.
142  llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes;
143 
144  /// Hold memoized CGFunctionInfo results.
145  llvm::FoldingSet<CGFunctionInfo> FunctionInfos;
146 
147  /// This set keeps track of records that we're currently converting
148  /// to an IR type. For example, when converting:
149  /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B'
150  /// types will be in this set.
151  llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut;
152 
153  llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed;
154 
155  /// True if we didn't layout a function due to a being inside
156  /// a recursive struct conversion, set this to true.
157  bool SkippedLayout;
158 
159  SmallVector<const RecordDecl *, 8> DeferredRecords;
160 
161  /// This map keeps cache of llvm::Types and maps clang::Type to
162  /// corresponding llvm::Type.
163  llvm::DenseMap<const Type *, llvm::Type *> TypeCache;
164 
165  llvm::SmallSet<const Type *, 8> RecordsWithOpaqueMemberPointers;
166 
167 public:
169  ~CodeGenTypes();
170 
171  const llvm::DataLayout &getDataLayout() const {
172  return TheModule.getDataLayout();
173  }
174  ASTContext &getContext() const { return Context; }
175  const ABIInfo &getABIInfo() const { return TheABIInfo; }
176  const TargetInfo &getTarget() const { return Target; }
177  CGCXXABI &getCXXABI() const { return TheCXXABI; }
178  llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); }
179  const CodeGenOptions &getCodeGenOpts() const;
180 
181  /// Convert clang calling convention to LLVM callilng convention.
182  unsigned ClangCallConvToLLVMCallConv(CallingConv CC);
183 
184  /// ConvertType - Convert type T into a llvm::Type.
185  llvm::Type *ConvertType(QualType T);
186 
187  /// \brief Converts the GlobalDecl into an llvm::Type. This should be used
188  /// when we know the target of the function we want to convert. This is
189  /// because some functions (explicitly, those with pass_object_size
190  /// parameters) may not have the same signature as their type portrays, and
191  /// can only be called directly.
192  llvm::Type *ConvertFunctionType(QualType FT,
193  const FunctionDecl *FD = nullptr);
194 
195  /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
196  /// ConvertType in that it is used to convert to the memory representation for
197  /// a type. For example, the scalar representation for _Bool is i1, but the
198  /// memory representation is usually i8 or i32, depending on the target.
199  llvm::Type *ConvertTypeForMem(QualType T);
200 
201  /// GetFunctionType - Get the LLVM function type for \arg Info.
202  llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info);
203 
204  llvm::FunctionType *GetFunctionType(GlobalDecl GD);
205 
206  /// isFuncTypeConvertible - Utility to check whether a function type can
207  /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag
208  /// type).
209  bool isFuncTypeConvertible(const FunctionType *FT);
210  bool isFuncParamTypeConvertible(QualType Ty);
211 
212  /// Determine if a C++ inheriting constructor should have parameters matching
213  /// those of its inherited constructor.
214  bool inheritingCtorHasParams(const InheritedConstructor &Inherited,
215  CXXCtorType Type);
216 
217  /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable,
218  /// given a CXXMethodDecl. If the method to has an incomplete return type,
219  /// and/or incomplete argument types, this will return the opaque type.
220  llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD);
221 
222  const CGRecordLayout &getCGRecordLayout(const RecordDecl*);
223 
224  /// UpdateCompletedType - When we find the full definition for a TagDecl,
225  /// replace the 'opaque' type we previously made for it if applicable.
226  void UpdateCompletedType(const TagDecl *TD);
227 
228  /// \brief Remove stale types from the type cache when an inheritance model
229  /// gets assigned to a class.
230  void RefreshTypeCacheForClass(const CXXRecordDecl *RD);
231 
232  // The arrangement methods are split into three families:
233  // - those meant to drive the signature and prologue/epilogue
234  // of a function declaration or definition,
235  // - those meant for the computation of the LLVM type for an abstract
236  // appearance of a function, and
237  // - those meant for performing the IR-generation of a call.
238  // They differ mainly in how they deal with optional (i.e. variadic)
239  // arguments, as well as unprototyped functions.
240  //
241  // Key points:
242  // - The CGFunctionInfo for emitting a specific call site must include
243  // entries for the optional arguments.
244  // - The function type used at the call site must reflect the formal
245  // signature of the declaration being called, or else the call will
246  // go awry.
247  // - For the most part, unprototyped functions are called by casting to
248  // a formal signature inferred from the specific argument types used
249  // at the call-site. However, some targets (e.g. x86-64) screw with
250  // this for compatibility reasons.
251 
252  const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD);
253 
254  /// Given a function info for a declaration, return the function info
255  /// for a call with the given arguments.
256  ///
257  /// Often this will be able to simply return the declaration info.
258  const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI,
259  const CallArgList &args);
260 
261  /// Free functions are functions that are compatible with an ordinary
262  /// C function pointer type.
263  const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD);
265  const FunctionType *Ty,
266  bool ChainCall);
268  const FunctionDecl *FD);
270 
271  /// A nullary function is a freestanding function of type 'void ()'.
272  /// This method works for both calls and declarations.
273  const CGFunctionInfo &arrangeNullaryFunction();
274 
275  /// A builtin function is a freestanding function using the default
276  /// C conventions.
277  const CGFunctionInfo &
278  arrangeBuiltinFunctionDeclaration(QualType resultType,
279  const FunctionArgList &args);
280  const CGFunctionInfo &
281  arrangeBuiltinFunctionDeclaration(CanQualType resultType,
282  ArrayRef<CanQualType> argTypes);
283  const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType,
284  const CallArgList &args);
285 
286  /// Objective-C methods are C functions with some implicit parameters.
287  const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD);
289  QualType receiverType);
290  const CGFunctionInfo &arrangeUnprototypedObjCMessageSend(
291  QualType returnType,
292  const CallArgList &args);
293 
294  /// Block invocation functions are C functions with an implicit parameter.
295  const CGFunctionInfo &arrangeBlockFunctionDeclaration(
296  const FunctionProtoType *type,
297  const FunctionArgList &args);
298  const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args,
299  const FunctionType *type);
300 
301  /// C++ methods have some special rules and also have implicit parameters.
302  const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD);
303  const CGFunctionInfo &arrangeCXXStructorDeclaration(const CXXMethodDecl *MD,
304  StructorType Type);
305  const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
306  const CXXConstructorDecl *D,
307  CXXCtorType CtorKind,
308  unsigned ExtraPrefixArgs,
309  unsigned ExtraSuffixArgs,
310  bool PassProtoArgs = true);
311 
312  const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
313  const FunctionProtoType *type,
314  RequiredArgs required,
315  unsigned numPrefixArgs);
316  const CGFunctionInfo &arrangeMSMemberPointerThunk(const CXXMethodDecl *MD);
317  const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
318  CXXCtorType CT);
320  const FunctionProtoType *FTP,
321  const CXXMethodDecl *MD);
322 
323  /// "Arrange" the LLVM information for a call or type with the given
324  /// signature. This is largely an internal method; other clients
325  /// should use one of the above routines, which ultimately defer to
326  /// this.
327  ///
328  /// \param argTypes - must all actually be canonical as params
329  const CGFunctionInfo &arrangeLLVMFunctionInfo(CanQualType returnType,
330  bool instanceMethod,
331  bool chainCall,
332  ArrayRef<CanQualType> argTypes,
335  RequiredArgs args);
336 
337  /// \brief Compute a new LLVM record layout object for the given record.
338  CGRecordLayout *ComputeRecordLayout(const RecordDecl *D,
339  llvm::StructType *Ty);
340 
341  /// addRecordTypeName - Compute a name from the given record decl with an
342  /// optional suffix and name the given LLVM type using it.
343  void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty,
344  StringRef suffix);
345 
346 
347 public: // These are internal details of CGT that shouldn't be used externally.
348  /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
349  llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD);
350 
351  /// getExpandedTypes - Expand the type \arg Ty into the LLVM
352  /// argument types it would be passed as. See ABIArgInfo::Expand.
353  void getExpandedTypes(QualType Ty,
355 
356  /// IsZeroInitializable - Return whether a type can be
357  /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
358  bool isZeroInitializable(QualType T);
359 
360  /// Check if the pointer type can be zero-initialized (in the C++ sense)
361  /// with an LLVM zeroinitializer.
362  bool isPointerZeroInitializable(QualType T);
363 
364  /// IsZeroInitializable - Return whether a record type can be
365  /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer.
366  bool isZeroInitializable(const RecordDecl *RD);
367 
368  bool isRecordLayoutComplete(const Type *Ty) const;
369  bool noRecordsBeingLaidOut() const {
370  return RecordsBeingLaidOut.empty();
371  }
372  bool isRecordBeingLaidOut(const Type *Ty) const {
373  return RecordsBeingLaidOut.count(Ty);
374  }
375 
376 };
377 
378 } // end namespace CodeGen
379 } // end namespace clang
380 
381 #endif
bool noRecordsBeingLaidOut() const
Definition: CodeGenTypes.h:369
CGCXXABI & getCXXABI() const
Definition: CodeGenTypes.h:177
FunctionDecl - An instance of this class is created to represent a function declaration or definition...
Definition: Decl.h:1698
Complete object ctor.
Definition: ABI.h:26
A (possibly-)qualified type.
Definition: Type.h:653
CGRecordLayout - This class handles struct and union layout info while lowering AST types to LLVM typ...
The COMDAT used for ctors.
Definition: ABI.h:28
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:26
const ABIInfo & getABIInfo() const
Definition: CodeGenTypes.h:175
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3058
bool isRecordBeingLaidOut(const Type *Ty) const
Definition: CodeGenTypes.h:372
const llvm::DataLayout & getDataLayout() const
Definition: CodeGenTypes.h:171
The base class of the type hierarchy.
Definition: Type.h:1353
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2397
Default closure variant of a ctor.
Definition: ABI.h:30
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
const CGFunctionInfo & arrangeCXXMethodType(CodeGenModule &CGM, const CXXRecordDecl *RD, const FunctionProtoType *FTP, const CXXMethodDecl *MD)
RecordDecl - Represents a struct/union/class.
Definition: Decl.h:3482
Description of a constructor that was inherited from a base class.
Definition: DeclCXX.h:2371
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:149
StructorType getFromDtorType(CXXDtorType T)
Definition: CodeGenTypes.h:104
const CGFunctionInfo & arrangeFreeFunctionType(CodeGenModule &CGM, CanQual< FunctionProtoType > Ty, const FunctionDecl *FD)
Base object ctor.
Definition: ABI.h:27
Deleting dtor.
Definition: ABI.h:35
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:3270
Exposes information about the current target.
Definition: TargetInfo.h:54
CXXDtorType
C++ destructor types.
Definition: ABI.h:34
const FunctionProtoType * T
A class for recording the number of arguments that a function signature requires. ...
Base object dtor.
Definition: ABI.h:37
The COMDAT used for dtors.
Definition: ABI.h:38
CallingConv
CallingConv - Specifies the calling convention that a function uses.
Definition: Specifiers.h:233
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:35
The l-value was considered opaque, so the alignment was determined from a type.
TagDecl - Represents the declaration of a struct/union/class/enum.
Definition: Decl.h:2938
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:1964
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:178
Complete object dtor.
Definition: ABI.h:36
CXXCtorType
C++ constructor types.
Definition: ABI.h:25
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:276
const TargetInfo & getTarget() const
Definition: CodeGenTypes.h:176
CGFunctionInfo - Class to encapsulate the information about a function definition.
This class organizes the cross-function state that is used while generating LLVM code.
Dataflow Directional Tag Classes.
CXXDtorType toCXXDtorType(StructorType T)
Definition: CodeGenTypes.h:92
static const CGFunctionInfo & arrangeLLVMFunctionInfo(CodeGenTypes &CGT, bool instanceMethod, SmallVectorImpl< CanQualType > &prefix, CanQual< FunctionProtoType > FTP, const FunctionDecl *FD)
Arrange the LLVM function layout for a value of the given function type, on top of any implicit param...
Definition: CGCall.cpp:167
StructorType getFromCtorType(CXXCtorType T)
Definition: CodeGenTypes.h:77
Implements C++ ABI-specific code generation functions.
Definition: CGCXXABI.h:44
This class organizes the cross-module state that is used while lowering AST types to LLVM types...
Definition: CodeGenTypes.h:120
CodeGenOptions - Track various options which control how the code is optimized and passed to the back...
ASTContext & getContext() const
Definition: CodeGenTypes.h:174
Represents a C++ struct/union/class.
Definition: DeclCXX.h:299
Copying closure variant of a ctor.
Definition: ABI.h:29
ABIInfo - Target specific hooks for defining how a type should be passed or returned from functions...
Definition: ABIInfo.h:51
CXXCtorType toCXXCtorType(StructorType T)
Definition: CodeGenTypes.h:65
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:182
A class which abstracts out some details necessary for making a call.
Definition: Type.h:3083