CGObjCRuntime.h source code [clang_source_code/lib/CodeGen/CGObjCRuntime.h]

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.
63	class CGObjCRuntime {
64	protected:
65	CodeGen::CodeGenModule &CGM;
66	CGObjCRuntime(CodeGen::CodeGenModule &CGM) : CGM(CGM) {}
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,
90	llvm::Value *Offset);
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
235	virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) {
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
288	struct MessageSendInfo {
289	const CGFunctionInfo &CallInfo;
290	llvm::PointerType *MessengerType;
291
292	MessageSendInfo(const CGFunctionInfo &callInfo,
293	llvm::PointerType *messengerType)
294	: CallInfo(callInfo), MessengerType(messengerType) {}
295	};
296
297	MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
298	QualType resultType,
299	CallArgList &callArgs);
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.
310	CGObjCRuntime *CreateGNUObjCRuntime(CodeGenModule &CGM);
311	CGObjCRuntime *CreateMacObjCRuntime(CodeGenModule &CGM);
312	}
313	}
314	#endif
315