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