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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 to the super
173  /// class initiated in a method for Class and with the given Self
174  /// object.
175  ///
176  /// \param Method - The method being called, this may be null if synthesizing
177  /// a property setter or getter.
178  virtual CodeGen::RValue
179  GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
180  ReturnValueSlot ReturnSlot,
181  QualType ResultType,
182  Selector Sel,
183  const ObjCInterfaceDecl *Class,
184  bool isCategoryImpl,
185  llvm::Value *Self,
186  bool IsClassMessage,
187  const CallArgList &CallArgs,
188  const ObjCMethodDecl *Method = nullptr) = 0;
189 
190  /// Emit the code to return the named protocol as an object, as in a
191  /// \@protocol expression.
192  virtual llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
193  const ObjCProtocolDecl *OPD) = 0;
194 
195  /// Generate the named protocol. Protocols contain method metadata but no
196  /// implementations.
197  virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;
198 
199  /// Generate a function preamble for a method with the specified
200  /// types.
201 
202  // FIXME: Current this just generates the Function definition, but really this
203  // should also be generating the loads of the parameters, as the runtime
204  // should have full control over how parameters are passed.
205  virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
206  const ObjCContainerDecl *CD) = 0;
207 
208  /// Return the runtime function for getting properties.
209  virtual llvm::FunctionCallee GetPropertyGetFunction() = 0;
210 
211  /// Return the runtime function for setting properties.
212  virtual llvm::FunctionCallee GetPropertySetFunction() = 0;
213 
214  /// Return the runtime function for optimized setting properties.
215  virtual llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
216  bool copy) = 0;
217 
218  // API for atomic copying of qualified aggregates in getter.
219  virtual llvm::FunctionCallee GetGetStructFunction() = 0;
220  // API for atomic copying of qualified aggregates in setter.
221  virtual llvm::FunctionCallee GetSetStructFunction() = 0;
222  /// API for atomic copying of qualified aggregates with non-trivial copy
223  /// assignment (c++) in setter.
224  virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0;
225  /// API for atomic copying of qualified aggregates with non-trivial copy
226  /// assignment (c++) in getter.
227  virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0;
228 
229  /// GetClass - Return a reference to the class for the given
230  /// interface decl.
231  virtual llvm::Value *GetClass(CodeGenFunction &CGF,
232  const ObjCInterfaceDecl *OID) = 0;
233 
234 
236  llvm_unreachable("autoreleasepool unsupported in this ABI");
237  }
238 
239  /// EnumerationMutationFunction - Return the function that's called by the
240  /// compiler when a mutation is detected during foreach iteration.
241  virtual llvm::FunctionCallee EnumerationMutationFunction() = 0;
242 
243  virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
244  const ObjCAtSynchronizedStmt &S) = 0;
245  virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF,
246  const ObjCAtTryStmt &S) = 0;
247  virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
248  const ObjCAtThrowStmt &S,
249  bool ClearInsertionPoint=true) = 0;
250  virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
251  Address AddrWeakObj) = 0;
252  virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
253  llvm::Value *src, Address dest) = 0;
254  virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
255  llvm::Value *src, Address dest,
256  bool threadlocal=false) = 0;
257  virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
258  llvm::Value *src, Address dest,
259  llvm::Value *ivarOffset) = 0;
260  virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
261  llvm::Value *src, Address dest) = 0;
262 
263  virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
264  QualType ObjectTy,
265  llvm::Value *BaseValue,
266  const ObjCIvarDecl *Ivar,
267  unsigned CVRQualifiers) = 0;
268  virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
269  const ObjCInterfaceDecl *Interface,
270  const ObjCIvarDecl *Ivar) = 0;
271  virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
272  Address DestPtr,
273  Address SrcPtr,
274  llvm::Value *Size) = 0;
275  virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
276  const CodeGen::CGBlockInfo &blockInfo) = 0;
277  virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
278  const CodeGen::CGBlockInfo &blockInfo) = 0;
279  virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM,
280  const CGBlockInfo &blockInfo) {
281  return {};
282  }
283 
284  /// Returns an i8* which points to the byref layout information.
285  virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
286  QualType T) = 0;
287 
290  llvm::PointerType *MessengerType;
291 
293  llvm::PointerType *messengerType)
294  : CallInfo(callInfo), MessengerType(messengerType) {}
295  };
296 
297  MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
298  QualType resultType,
300 
301  // FIXME: This probably shouldn't be here, but the code to compute
302  // it is here.
303  unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM,
304  const ObjCInterfaceDecl *ID,
305  const ObjCIvarDecl *Ivar);
306 };
307 
308 /// Creates an instance of an Objective-C runtime class.
309 //TODO: This should include some way of selecting which runtime to target.
312 }
313 }
314 #endif
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:363
Smart pointer class that efficiently represents Objective-C method names.
A (possibly-)qualified type.
Definition: Type.h:643
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:827
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:968
CGObjCRuntime * CreateMacObjCRuntime(CodeGenModule &CGM)
CodeGen::CodeGenModule & CGM
Definition: CGObjCRuntime.h:65
Represents an Objective-C protocol declaration.
Definition: DeclObjC.h:2063
Represents an ObjC class declaration.
Definition: DeclObjC.h:1171
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:38
unsigned Offset
Definition: Format.cpp:1809
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:2551
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:1944
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:1686
LValue - This represents an lvalue references.
Definition: CGValue.h:166
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:262
ObjCCategoryImplDecl - An object of this class encapsulates a category @implementation declaration...
Definition: DeclObjC.h:2498
ObjCCompatibleAliasDecl - Represents alias of a class.
Definition: DeclObjC.h:2728
CGObjCRuntime * CreateGNUObjCRuntime(CodeGenModule &CGM)
Creates an instance of an Objective-C runtime class.
Definition: CGObjCGNU.cpp:4103