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#include "llvm/ADT/UniqueVector.h"
24
25namespace llvm {
26 class Constant;
27 class Function;
28 class Module;
29 class StructLayout;
30 class StructType;
31 class Type;
32 class Value;
33}
34
35namespace clang {
36namespace CodeGen {
37class CGFunctionInfo;
38class CodeGenFunction;
39}
40
41 class FieldDecl;
42 class ObjCAtTryStmt;
43 class ObjCAtThrowStmt;
44 class ObjCAtSynchronizedStmt;
45 class ObjCContainerDecl;
46 class ObjCCategoryImplDecl;
47 class ObjCImplementationDecl;
48 class ObjCInterfaceDecl;
49 class ObjCMessageExpr;
50 class ObjCMethodDecl;
51 class ObjCProtocolDecl;
52 class Selector;
53 class ObjCIvarDecl;
54 class ObjCStringLiteral;
55 class BlockDeclRefExpr;
56
57namespace CodeGen {
58 class CodeGenModule;
59 class CGBlockInfo;
60
61// FIXME: Several methods should be pure virtual but aren't to avoid the
62// partially-implemented subclass breaking.
63
64/// Implements runtime-specific code generation functions.
65class CGObjCRuntime {
66protected:
67 CodeGen::CodeGenModule &CGM;
68 CGObjCRuntime(CodeGen::CodeGenModule &CGM) : CGM(CGM) {}
69
70 // Utility functions for unified ivar access. These need to
71 // eventually be folded into other places (the structure layout
72 // code).
73
74 /// Compute an offset to the given ivar, suitable for passing to
75 /// EmitValueForIvarAtOffset. Note that the correct handling of
76 /// bit-fields is carefully coordinated by these two, use caution!
77 ///
78 /// The latter overload is suitable for computing the offset of a
79 /// sythesized ivar.
80 uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
81 const ObjCInterfaceDecl *OID,
82 const ObjCIvarDecl *Ivar);
83 uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
84 const ObjCImplementationDecl *OID,
85 const ObjCIvarDecl *Ivar);
86
87 LValue EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
88 const ObjCInterfaceDecl *OID,
89 llvm::Value *BaseValue,
90 const ObjCIvarDecl *Ivar,
91 unsigned CVRQualifiers,
92 llvm::Value *Offset);
93 /// Emits a try / catch statement. This function is intended to be called by
94 /// subclasses, and provides a generic mechanism for generating these, which
95 /// should be usable by all runtimes. The caller must provide the functions
96 /// to call when entering and exiting a \@catch() block, and the function
97 /// used to rethrow exceptions. If the begin and end catch functions are
98 /// NULL, then the function assumes that the EH personality function provides
99 /// the thrown object directly.
100 void EmitTryCatchStmt(CodeGenFunction &CGF, const ObjCAtTryStmt &S,
101 llvm::FunctionCallee beginCatchFn,
102 llvm::FunctionCallee endCatchFn,
103 llvm::FunctionCallee exceptionRethrowFn);
104
105 void EmitInitOfCatchParam(CodeGenFunction &CGF, llvm::Value *exn,
106 const VarDecl *paramDecl);
107
108 /// Emits an \@synchronize() statement, using the \p syncEnterFn and
109 /// \p syncExitFn arguments as the functions called to lock and unlock
110 /// the object. This function can be called by subclasses that use
111 /// zero-cost exception handling.
112 void EmitAtSynchronizedStmt(CodeGenFunction &CGF,
113 const ObjCAtSynchronizedStmt &S,
114 llvm::FunctionCallee syncEnterFn,
115 llvm::FunctionCallee syncExitFn);
116
117public:
118 virtual ~CGObjCRuntime();
119
120 std::string getSymbolNameForMethod(const ObjCMethodDecl *method,
121 bool includeCategoryName = true);
122
123 /// Generate the function required to register all Objective-C components in
124 /// this compilation unit with the runtime library.
125 virtual llvm::Function *ModuleInitFunction() = 0;
126
127 /// Get a selector for the specified name and type values.
128 /// The result should have the LLVM type for ASTContext::getObjCSelType().
129 virtual llvm::Value *GetSelector(CodeGenFunction &CGF, Selector Sel) = 0;
130
131 /// Get the address of a selector for the specified name and type values.
132 /// This is a rarely-used language extension, but sadly it exists.
133 ///
134 /// The result should have the LLVM type for a pointer to
135 /// ASTContext::getObjCSelType().
136 virtual Address GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) = 0;
137
138 /// Get a typed selector.
139 virtual llvm::Value *GetSelector(CodeGenFunction &CGF,
140 const ObjCMethodDecl *Method) = 0;
141
142 /// Get the type constant to catch for the given ObjC pointer type.
143 /// This is used externally to implement catching ObjC types in C++.
144 /// Runtimes which don't support this should add the appropriate
145 /// error to Sema.
146 virtual llvm::Constant *GetEHType(QualType T) = 0;
147
148 virtual CatchTypeInfo getCatchAllTypeInfo() { return { .RTTI: nullptr, .Flags: 0 }; }
149
150 /// Generate a constant string object.
151 virtual ConstantAddress GenerateConstantString(const StringLiteral *) = 0;
152
153 /// Generate a category. A category contains a list of methods (and
154 /// accompanying metadata) and a list of protocols.
155 virtual void GenerateCategory(const ObjCCategoryImplDecl *OCD) = 0;
156
157 /// Generate a class structure for this class.
158 virtual void GenerateClass(const ObjCImplementationDecl *OID) = 0;
159
160 /// Register an class alias.
161 virtual void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) = 0;
162
163 /// Generate an Objective-C message send operation.
164 ///
165 /// \param Method - The method being called, this may be null if synthesizing
166 /// a property setter or getter.
167 virtual CodeGen::RValue
168 GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
169 ReturnValueSlot ReturnSlot,
170 QualType ResultType,
171 Selector Sel,
172 llvm::Value *Receiver,
173 const CallArgList &CallArgs,
174 const ObjCInterfaceDecl *Class = nullptr,
175 const ObjCMethodDecl *Method = nullptr) = 0;
176
177 /// Generate an Objective-C message send operation.
178 ///
179 /// This variant allows for the call to be substituted with an optimized
180 /// variant.
181 CodeGen::RValue
182 GeneratePossiblySpecializedMessageSend(CodeGenFunction &CGF,
183 ReturnValueSlot Return,
184 QualType ResultType,
185 Selector Sel,
186 llvm::Value *Receiver,
187 const CallArgList& Args,
188 const ObjCInterfaceDecl *OID,
189 const ObjCMethodDecl *Method,
190 bool isClassMessage);
191
192 /// Generate an Objective-C message send operation to the super
193 /// class initiated in a method for Class and with the given Self
194 /// object.
195 ///
196 /// \param Method - The method being called, this may be null if synthesizing
197 /// a property setter or getter.
198 virtual CodeGen::RValue
199 GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
200 ReturnValueSlot ReturnSlot,
201 QualType ResultType,
202 Selector Sel,
203 const ObjCInterfaceDecl *Class,
204 bool isCategoryImpl,
205 llvm::Value *Self,
206 bool IsClassMessage,
207 const CallArgList &CallArgs,
208 const ObjCMethodDecl *Method = nullptr) = 0;
209
210 /// Walk the list of protocol references from a class, category or
211 /// protocol to traverse the DAG formed from it's inheritance hierarchy. Find
212 /// the list of protocols that ends each walk at either a runtime
213 /// protocol or a non-runtime protocol with no parents. For the common case of
214 /// just a list of standard runtime protocols this just returns the same list
215 /// that was passed in.
216 std::vector<const ObjCProtocolDecl *>
217 GetRuntimeProtocolList(ObjCProtocolDecl::protocol_iterator begin,
218 ObjCProtocolDecl::protocol_iterator end);
219
220 /// Emit the code to return the named protocol as an object, as in a
221 /// \@protocol expression.
222 virtual llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
223 const ObjCProtocolDecl *OPD) = 0;
224
225 /// Generate the named protocol. Protocols contain method metadata but no
226 /// implementations.
227 virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;
228
229 /// GetOrEmitProtocol - Get the protocol object for the given
230 /// declaration, emitting it if necessary. The return value has type
231 /// ProtocolPtrTy.
232 virtual llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) = 0;
233
234 /// Generate a function preamble for a method with the specified
235 /// types.
236
237 // FIXME: Current this just generates the Function definition, but really this
238 // should also be generating the loads of the parameters, as the runtime
239 // should have full control over how parameters are passed.
240 virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
241 const ObjCContainerDecl *CD) = 0;
242
243 /// Generates prologue for direct Objective-C Methods.
244 virtual void GenerateDirectMethodPrologue(CodeGenFunction &CGF,
245 llvm::Function *Fn,
246 const ObjCMethodDecl *OMD,
247 const ObjCContainerDecl *CD) = 0;
248
249 /// Return the runtime function for getting properties.
250 virtual llvm::FunctionCallee GetPropertyGetFunction() = 0;
251
252 /// Return the runtime function for setting properties.
253 virtual llvm::FunctionCallee GetPropertySetFunction() = 0;
254
255 /// Return the runtime function for optimized setting properties.
256 virtual llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
257 bool copy) = 0;
258
259 // API for atomic copying of qualified aggregates in getter.
260 virtual llvm::FunctionCallee GetGetStructFunction() = 0;
261 // API for atomic copying of qualified aggregates in setter.
262 virtual llvm::FunctionCallee GetSetStructFunction() = 0;
263 /// API for atomic copying of qualified aggregates with non-trivial copy
264 /// assignment (c++) in setter.
265 virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0;
266 /// API for atomic copying of qualified aggregates with non-trivial copy
267 /// assignment (c++) in getter.
268 virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0;
269
270 /// GetClass - Return a reference to the class for the given
271 /// interface decl.
272 virtual llvm::Value *GetClass(CodeGenFunction &CGF,
273 const ObjCInterfaceDecl *OID) = 0;
274
275
276 virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) {
277 llvm_unreachable("autoreleasepool unsupported in this ABI");
278 }
279
280 /// EnumerationMutationFunction - Return the function that's called by the
281 /// compiler when a mutation is detected during foreach iteration.
282 virtual llvm::FunctionCallee EnumerationMutationFunction() = 0;
283
284 virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
285 const ObjCAtSynchronizedStmt &S) = 0;
286 virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF,
287 const ObjCAtTryStmt &S) = 0;
288 virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
289 const ObjCAtThrowStmt &S,
290 bool ClearInsertionPoint=true) = 0;
291 virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
292 Address AddrWeakObj) = 0;
293 virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
294 llvm::Value *src, Address dest) = 0;
295 virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
296 llvm::Value *src, Address dest,
297 bool threadlocal=false) = 0;
298 virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
299 llvm::Value *src, Address dest,
300 llvm::Value *ivarOffset) = 0;
301 virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
302 llvm::Value *src, Address dest) = 0;
303
304 virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
305 QualType ObjectTy,
306 llvm::Value *BaseValue,
307 const ObjCIvarDecl *Ivar,
308 unsigned CVRQualifiers) = 0;
309 virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
310 const ObjCInterfaceDecl *Interface,
311 const ObjCIvarDecl *Ivar) = 0;
312 virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
313 Address DestPtr,
314 Address SrcPtr,
315 llvm::Value *Size) = 0;
316 virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
317 const CodeGen::CGBlockInfo &blockInfo) = 0;
318 virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
319 const CodeGen::CGBlockInfo &blockInfo) = 0;
320 virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM,
321 const CGBlockInfo &blockInfo) {
322 return {};
323 }
324
325 /// Returns an i8* which points to the byref layout information.
326 virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
327 QualType T) = 0;
328
329 struct MessageSendInfo {
330 const CGFunctionInfo &CallInfo;
331 llvm::PointerType *MessengerType;
332
333 MessageSendInfo(const CGFunctionInfo &callInfo,
334 llvm::PointerType *messengerType)
335 : CallInfo(callInfo), MessengerType(messengerType) {}
336 };
337
338 MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
339 QualType resultType,
340 CallArgList &callArgs);
341 bool canMessageReceiverBeNull(CodeGenFunction &CGF,
342 const ObjCMethodDecl *method,
343 bool isSuper,
344 const ObjCInterfaceDecl *classReceiver,
345 llvm::Value *receiver);
346 static bool isWeakLinkedClass(const ObjCInterfaceDecl *cls);
347
348 /// Destroy the callee-destroyed arguments of the given method,
349 /// if it has any. Used for nil-receiver paths in message sends.
350 /// Never does anything if the method does not satisfy
351 /// hasParamDestroyedInCallee().
352 ///
353 /// \param callArgs - just the formal arguments, not including implicit
354 /// arguments such as self and cmd
355 static void destroyCalleeDestroyedArguments(CodeGenFunction &CGF,
356 const ObjCMethodDecl *method,
357 const CallArgList &callArgs);
358
359 // FIXME: This probably shouldn't be here, but the code to compute
360 // it is here.
361 unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM,
362 const ObjCInterfaceDecl *ID,
363 const ObjCIvarDecl *Ivar);
364};
365
366/// Creates an instance of an Objective-C runtime class.
367//TODO: This should include some way of selecting which runtime to target.
368CGObjCRuntime *CreateGNUObjCRuntime(CodeGenModule &CGM);
369CGObjCRuntime *CreateMacObjCRuntime(CodeGenModule &CGM);
370}
371}
372#endif
373

source code of clang/lib/CodeGen/CGObjCRuntime.h