clang  10.0.0git
CGObjCRuntime.h
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1 //===----- CGObjCRuntime.h - Interface to ObjC Runtimes ---------*- 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 provides an abstract class for Objective-C code generation. Concrete
10 // subclasses of this implement code generation for specific Objective-C
11 // runtime libraries.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H
16 #define LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H
17 #include "CGBuilder.h"
18 #include "CGCall.h"
19 #include "CGCleanup.h"
20 #include "CGValue.h"
21 #include "clang/AST/DeclObjC.h"
22 #include "clang/Basic/IdentifierTable.h" // Selector
23 
24 namespace llvm {
25  class Constant;
26  class Function;
27  class Module;
28  class StructLayout;
29  class StructType;
30  class Type;
31  class Value;
32 }
33 
34 namespace clang {
35 namespace CodeGen {
36  class CodeGenFunction;
37 }
38 
39  class FieldDecl;
40  class ObjCAtTryStmt;
41  class ObjCAtThrowStmt;
42  class ObjCAtSynchronizedStmt;
43  class ObjCContainerDecl;
44  class ObjCCategoryImplDecl;
45  class ObjCImplementationDecl;
46  class ObjCInterfaceDecl;
47  class ObjCMessageExpr;
48  class ObjCMethodDecl;
49  class ObjCProtocolDecl;
50  class Selector;
51  class ObjCIvarDecl;
52  class ObjCStringLiteral;
53  class BlockDeclRefExpr;
54 
55 namespace CodeGen {
56  class CodeGenModule;
57  class CGBlockInfo;
58 
59 // FIXME: Several methods should be pure virtual but aren't to avoid the
60 // partially-implemented subclass breaking.
61 
62 /// Implements runtime-specific code generation functions.
64 protected:
67 
68  // Utility functions for unified ivar access. These need to
69  // eventually be folded into other places (the structure layout
70  // code).
71 
72  /// Compute an offset to the given ivar, suitable for passing to
73  /// EmitValueForIvarAtOffset. Note that the correct handling of
74  /// bit-fields is carefully coordinated by these two, use caution!
75  ///
76  /// The latter overload is suitable for computing the offset of a
77  /// sythesized ivar.
78  uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
79  const ObjCInterfaceDecl *OID,
80  const ObjCIvarDecl *Ivar);
81  uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
82  const ObjCImplementationDecl *OID,
83  const ObjCIvarDecl *Ivar);
84 
85  LValue EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
86  const ObjCInterfaceDecl *OID,
87  llvm::Value *BaseValue,
88  const ObjCIvarDecl *Ivar,
89  unsigned CVRQualifiers,
91  /// Emits a try / catch statement. This function is intended to be called by
92  /// subclasses, and provides a generic mechanism for generating these, which
93  /// should be usable by all runtimes. The caller must provide the functions
94  /// to call when entering and exiting a \@catch() block, and the function
95  /// used to rethrow exceptions. If the begin and end catch functions are
96  /// NULL, then the function assumes that the EH personality function provides
97  /// the thrown object directly.
98  void EmitTryCatchStmt(CodeGenFunction &CGF, const ObjCAtTryStmt &S,
99  llvm::FunctionCallee beginCatchFn,
100  llvm::FunctionCallee endCatchFn,
101  llvm::FunctionCallee exceptionRethrowFn);
102 
103  void EmitInitOfCatchParam(CodeGenFunction &CGF, llvm::Value *exn,
104  const VarDecl *paramDecl);
105 
106  /// Emits an \@synchronize() statement, using the \p syncEnterFn and
107  /// \p syncExitFn arguments as the functions called to lock and unlock
108  /// the object. This function can be called by subclasses that use
109  /// zero-cost exception handling.
110  void EmitAtSynchronizedStmt(CodeGenFunction &CGF,
111  const ObjCAtSynchronizedStmt &S,
112  llvm::FunctionCallee syncEnterFn,
113  llvm::FunctionCallee syncExitFn);
114 
115 public:
116  virtual ~CGObjCRuntime();
117 
118  /// Generate the function required to register all Objective-C components in
119  /// this compilation unit with the runtime library.
120  virtual llvm::Function *ModuleInitFunction() = 0;
121 
122  /// Get a selector for the specified name and type values.
123  /// The result should have the LLVM type for ASTContext::getObjCSelType().
124  virtual llvm::Value *GetSelector(CodeGenFunction &CGF, Selector Sel) = 0;
125 
126  /// Get the address of a selector for the specified name and type values.
127  /// This is a rarely-used language extension, but sadly it exists.
128  ///
129  /// The result should have the LLVM type for a pointer to
130  /// ASTContext::getObjCSelType().
131  virtual Address GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) = 0;
132 
133  /// Get a typed selector.
134  virtual llvm::Value *GetSelector(CodeGenFunction &CGF,
135  const ObjCMethodDecl *Method) = 0;
136 
137  /// Get the type constant to catch for the given ObjC pointer type.
138  /// This is used externally to implement catching ObjC types in C++.
139  /// Runtimes which don't support this should add the appropriate
140  /// error to Sema.
141  virtual llvm::Constant *GetEHType(QualType T) = 0;
142 
143  virtual CatchTypeInfo getCatchAllTypeInfo() { return { nullptr, 0 }; }
144 
145  /// Generate a constant string object.
146  virtual ConstantAddress GenerateConstantString(const StringLiteral *) = 0;
147 
148  /// Generate a category. A category contains a list of methods (and
149  /// accompanying metadata) and a list of protocols.
150  virtual void GenerateCategory(const ObjCCategoryImplDecl *OCD) = 0;
151 
152  /// Generate a class structure for this class.
153  virtual void GenerateClass(const ObjCImplementationDecl *OID) = 0;
154 
155  /// Register an class alias.
156  virtual void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) = 0;
157 
158  /// Generate an Objective-C message send operation.
159  ///
160  /// \param Method - The method being called, this may be null if synthesizing
161  /// a property setter or getter.
162  virtual CodeGen::RValue
163  GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
164  ReturnValueSlot ReturnSlot,
165  QualType ResultType,
166  Selector Sel,
167  llvm::Value *Receiver,
168  const CallArgList &CallArgs,
169  const ObjCInterfaceDecl *Class = nullptr,
170  const ObjCMethodDecl *Method = nullptr) = 0;
171 
172  /// Generate an Objective-C message send operation.
173  ///
174  /// This variant allows for the call to be substituted with an optimized
175  /// variant.
177  GeneratePossiblySpecializedMessageSend(CodeGenFunction &CGF,
178  ReturnValueSlot Return,
179  QualType ResultType,
180  Selector Sel,
181  llvm::Value *Receiver,
182  const CallArgList& Args,
183  const ObjCInterfaceDecl *OID,
184  const ObjCMethodDecl *Method,
185  bool isClassMessage);
186 
187  /// Generate an Objective-C message send operation to the super
188  /// class initiated in a method for Class and with the given Self
189  /// object.
190  ///
191  /// \param Method - The method being called, this may be null if synthesizing
192  /// a property setter or getter.
193  virtual CodeGen::RValue
194  GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
195  ReturnValueSlot ReturnSlot,
196  QualType ResultType,
197  Selector Sel,
198  const ObjCInterfaceDecl *Class,
199  bool isCategoryImpl,
200  llvm::Value *Self,
201  bool IsClassMessage,
202  const CallArgList &CallArgs,
203  const ObjCMethodDecl *Method = nullptr) = 0;
204 
205  /// Emit the code to return the named protocol as an object, as in a
206  /// \@protocol expression.
207  virtual llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
208  const ObjCProtocolDecl *OPD) = 0;
209 
210  /// Generate the named protocol. Protocols contain method metadata but no
211  /// implementations.
212  virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;
213 
214  /// Generate a function preamble for a method with the specified
215  /// types.
216 
217  // FIXME: Current this just generates the Function definition, but really this
218  // should also be generating the loads of the parameters, as the runtime
219  // should have full control over how parameters are passed.
220  virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
221  const ObjCContainerDecl *CD) = 0;
222 
223  /// Generates prologue for direct Objective-C Methods.
224  virtual void GenerateDirectMethodPrologue(CodeGenFunction &CGF,
225  llvm::Function *Fn,
226  const ObjCMethodDecl *OMD,
227  const ObjCContainerDecl *CD) = 0;
228 
229  /// Return the runtime function for getting properties.
230  virtual llvm::FunctionCallee GetPropertyGetFunction() = 0;
231 
232  /// Return the runtime function for setting properties.
233  virtual llvm::FunctionCallee GetPropertySetFunction() = 0;
234 
235  /// Return the runtime function for optimized setting properties.
236  virtual llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
237  bool copy) = 0;
238 
239  // API for atomic copying of qualified aggregates in getter.
240  virtual llvm::FunctionCallee GetGetStructFunction() = 0;
241  // API for atomic copying of qualified aggregates in setter.
242  virtual llvm::FunctionCallee GetSetStructFunction() = 0;
243  /// API for atomic copying of qualified aggregates with non-trivial copy
244  /// assignment (c++) in setter.
245  virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0;
246  /// API for atomic copying of qualified aggregates with non-trivial copy
247  /// assignment (c++) in getter.
248  virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0;
249 
250  /// GetClass - Return a reference to the class for the given
251  /// interface decl.
252  virtual llvm::Value *GetClass(CodeGenFunction &CGF,
253  const ObjCInterfaceDecl *OID) = 0;
254 
255 
257  llvm_unreachable("autoreleasepool unsupported in this ABI");
258  }
259 
260  /// EnumerationMutationFunction - Return the function that's called by the
261  /// compiler when a mutation is detected during foreach iteration.
262  virtual llvm::FunctionCallee EnumerationMutationFunction() = 0;
263 
264  virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
265  const ObjCAtSynchronizedStmt &S) = 0;
266  virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF,
267  const ObjCAtTryStmt &S) = 0;
268  virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
269  const ObjCAtThrowStmt &S,
270  bool ClearInsertionPoint=true) = 0;
271  virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
272  Address AddrWeakObj) = 0;
273  virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
274  llvm::Value *src, Address dest) = 0;
275  virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
276  llvm::Value *src, Address dest,
277  bool threadlocal=false) = 0;
278  virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
279  llvm::Value *src, Address dest,
280  llvm::Value *ivarOffset) = 0;
281  virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
282  llvm::Value *src, Address dest) = 0;
283 
284  virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
285  QualType ObjectTy,
286  llvm::Value *BaseValue,
287  const ObjCIvarDecl *Ivar,
288  unsigned CVRQualifiers) = 0;
289  virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
290  const ObjCInterfaceDecl *Interface,
291  const ObjCIvarDecl *Ivar) = 0;
292  virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
293  Address DestPtr,
294  Address SrcPtr,
295  llvm::Value *Size) = 0;
296  virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
297  const CodeGen::CGBlockInfo &blockInfo) = 0;
298  virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
299  const CodeGen::CGBlockInfo &blockInfo) = 0;
300  virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM,
301  const CGBlockInfo &blockInfo) {
302  return {};
303  }
304 
305  /// Returns an i8* which points to the byref layout information.
306  virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
307  QualType T) = 0;
308 
311  llvm::PointerType *MessengerType;
312 
314  llvm::PointerType *messengerType)
315  : CallInfo(callInfo), MessengerType(messengerType) {}
316  };
317 
318  MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
319  QualType resultType,
321 
322  // FIXME: This probably shouldn't be here, but the code to compute
323  // it is here.
324  unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM,
325  const ObjCInterfaceDecl *ID,
326  const ObjCIvarDecl *Ivar);
327 };
328 
329 /// Creates an instance of an Objective-C runtime class.
330 //TODO: This should include some way of selecting which runtime to target.
333 }
334 }
335 #endif
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:359
Smart pointer class that efficiently represents Objective-C method names.
A (possibly-)qualified type.
Definition: Type.h:654
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
Implements runtime-specific code generation functions.
Definition: CGObjCRuntime.h:63
Represents Objective-C's @throw statement.
Definition: StmtObjC.h:332
constexpr XRayInstrMask Function
Definition: XRayInstr.h:38
Represents a variable declaration or definition.
Definition: Decl.h:820
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:138
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
RangeSelector callArgs(std::string ID)
virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM, const CGBlockInfo &blockInfo)
ObjCContainerDecl - Represents a container for method declarations.
Definition: DeclObjC.h:983
CGObjCRuntime * CreateMacObjCRuntime(CodeGenModule &CGM)
CodeGen::CodeGenModule & CGM
Definition: CGObjCRuntime.h:65
Represents an Objective-C protocol declaration.
Definition: DeclObjC.h:2078
Represents an ObjC class declaration.
Definition: DeclObjC.h:1186
CGBlockInfo - Information to generate a block literal.
Definition: CGBlocks.h:152
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:39
unsigned Offset
Definition: Format.cpp:1827
CGObjCRuntime(CodeGen::CodeGenModule &CGM)
Definition: CGObjCRuntime.h:66
Represents Objective-C's @synchronized statement.
Definition: StmtObjC.h:277
Defines the clang::IdentifierInfo, clang::IdentifierTable, and clang::Selector interfaces.
virtual CatchTypeInfo getCatchAllTypeInfo()
MessageSendInfo(const CGFunctionInfo &callInfo, llvm::PointerType *messengerType)
virtual llvm::Value * EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF)
An aligned address.
Definition: Address.h:24
The MS C++ ABI needs a pointer to RTTI data plus some flags to describe the type of a catch handler...
Definition: CGCleanup.h:37
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.
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2566
A specialization of Address that requires the address to be an LLVM Constant.
Definition: Address.h:74
ObjCIvarDecl - Represents an ObjC instance variable.
Definition: DeclObjC.h:1959
Represents Objective-C&#39;s @try ... @catch ... @finally statement.
Definition: StmtObjC.h:165
StringLiteral - This represents a string literal expression, e.g.
Definition: Expr.h:1711
LValue - This represents an lvalue references.
Definition: CGValue.h:167
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:261
ObjCCategoryImplDecl - An object of this class encapsulates a category @implementation declaration...
Definition: DeclObjC.h:2513
ObjCCompatibleAliasDecl - Represents alias of a class.
Definition: DeclObjC.h:2743
CGObjCRuntime * CreateGNUObjCRuntime(CodeGenModule &CGM)
Creates an instance of an Objective-C runtime class.
Definition: CGObjCGNU.cpp:4114