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 {
37 class CodeGenFunction;
38}
39
40 class FieldDecl;
41 class ObjCAtTryStmt;
42 class ObjCAtThrowStmt;
43 class ObjCAtSynchronizedStmt;
44 class ObjCContainerDecl;
45 class ObjCCategoryImplDecl;
46 class ObjCImplementationDecl;
47 class ObjCInterfaceDecl;
48 class ObjCMessageExpr;
49 class ObjCMethodDecl;
50 class ObjCProtocolDecl;
51 class Selector;
52 class ObjCIvarDecl;
53 class ObjCStringLiteral;
54 class BlockDeclRefExpr;
55
56namespace CodeGen {
57 class CodeGenModule;
58 class CGBlockInfo;
59
60// FIXME: Several methods should be pure virtual but aren't to avoid the
61// partially-implemented subclass breaking.
62
63/// Implements runtime-specific code generation functions.
64class CGObjCRuntime {
65protected:
66 CodeGen::CodeGenModule &CGM;
67 CGObjCRuntime(CodeGen::CodeGenModule &CGM) : CGM(CGM) {}
68
69 // Utility functions for unified ivar access. These need to
70 // eventually be folded into other places (the structure layout
71 // code).
72
73 /// Compute an offset to the given ivar, suitable for passing to
74 /// EmitValueForIvarAtOffset. Note that the correct handling of
75 /// bit-fields is carefully coordinated by these two, use caution!
76 ///
77 /// The latter overload is suitable for computing the offset of a
78 /// sythesized ivar.
79 uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
80 const ObjCInterfaceDecl *OID,
81 const ObjCIvarDecl *Ivar);
82 uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
83 const ObjCImplementationDecl *OID,
84 const ObjCIvarDecl *Ivar);
85
86 LValue EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
87 const ObjCInterfaceDecl *OID,
88 llvm::Value *BaseValue,
89 const ObjCIvarDecl *Ivar,
90 unsigned CVRQualifiers,
91 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 { nullptr, 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,
168 ReturnValueSlot ReturnSlot,
169 QualType ResultType,
170 Selector Sel,
171 llvm::Value *Receiver,
172 const CallArgList &CallArgs,
173 const ObjCInterfaceDecl *Class = nullptr,
174 const ObjCMethodDecl *Method = nullptr) = 0;
175
176 /// Generate an Objective-C message send operation.
177 ///
178 /// This variant allows for the call to be substituted with an optimized
179 /// variant.
180 CodeGen::RValue
181 GeneratePossiblySpecializedMessageSend(CodeGenFunction &CGF,
182 ReturnValueSlot Return,
183 QualType ResultType,
184 Selector Sel,
185 llvm::Value *Receiver,
186 const CallArgList& Args,
187 const ObjCInterfaceDecl *OID,
188 const ObjCMethodDecl *Method,
189 bool isClassMessage);
190
191 /// Generate an Objective-C message send operation to the super
192 /// class initiated in a method for Class and with the given Self
193 /// object.
194 ///
195 /// \param Method - The method being called, this may be null if synthesizing
196 /// a property setter or getter.
197 virtual CodeGen::RValue
198 GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
199 ReturnValueSlot ReturnSlot,
200 QualType ResultType,
201 Selector Sel,
202 const ObjCInterfaceDecl *Class,
203 bool isCategoryImpl,
204 llvm::Value *Self,
205 bool IsClassMessage,
206 const CallArgList &CallArgs,
207 const ObjCMethodDecl *Method = nullptr) = 0;
208
209 /// Walk the list of protocol references from a class, category or
210 /// protocol to traverse the DAG formed from it's inheritance hierarchy. Find
211 /// the list of protocols that ends each walk at either a runtime
212 /// protocol or a non-runtime protocol with no parents. For the common case of
213 /// just a list of standard runtime protocols this just returns the same list
214 /// that was passed in.
215 std::vector<const ObjCProtocolDecl *>
216 GetRuntimeProtocolList(ObjCProtocolDecl::protocol_iterator begin,
217 ObjCProtocolDecl::protocol_iterator end);
218
219 /// Emit the code to return the named protocol as an object, as in a
220 /// \@protocol expression.
221 virtual llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
222 const ObjCProtocolDecl *OPD) = 0;
223
224 /// Generate the named protocol. Protocols contain method metadata but no
225 /// implementations.
226 virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;
227
228 /// GetOrEmitProtocol - Get the protocol object for the given
229 /// declaration, emitting it if necessary. The return value has type
230 /// ProtocolPtrTy.
231 virtual llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) = 0;
232
233 /// Generate a function preamble for a method with the specified
234 /// types.
235
236 // FIXME: Current this just generates the Function definition, but really this
237 // should also be generating the loads of the parameters, as the runtime
238 // should have full control over how parameters are passed.
239 virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
240 const ObjCContainerDecl *CD) = 0;
241
242 /// Generates prologue for direct Objective-C Methods.
243 virtual void GenerateDirectMethodPrologue(CodeGenFunction &CGF,
244 llvm::Function *Fn,
245 const ObjCMethodDecl *OMD,
246 const ObjCContainerDecl *CD) = 0;
247
248 /// Return the runtime function for getting properties.
249 virtual llvm::FunctionCallee GetPropertyGetFunction() = 0;
250
251 /// Return the runtime function for setting properties.
252 virtual llvm::FunctionCallee GetPropertySetFunction() = 0;
253
254 /// Return the runtime function for optimized setting properties.
255 virtual llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
256 bool copy) = 0;
257
258 // API for atomic copying of qualified aggregates in getter.
259 virtual llvm::FunctionCallee GetGetStructFunction() = 0;
260 // API for atomic copying of qualified aggregates in setter.
261 virtual llvm::FunctionCallee GetSetStructFunction() = 0;
262 /// API for atomic copying of qualified aggregates with non-trivial copy
263 /// assignment (c++) in setter.
264 virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0;
265 /// API for atomic copying of qualified aggregates with non-trivial copy
266 /// assignment (c++) in getter.
267 virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0;
268
269 /// GetClass - Return a reference to the class for the given
270 /// interface decl.
271 virtual llvm::Value *GetClass(CodeGenFunction &CGF,
272 const ObjCInterfaceDecl *OID) = 0;
273
274
275 virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) {
276 llvm_unreachable("autoreleasepool unsupported in this ABI");
277 }
278
279 /// EnumerationMutationFunction - Return the function that's called by the
280 /// compiler when a mutation is detected during foreach iteration.
281 virtual llvm::FunctionCallee EnumerationMutationFunction() = 0;
282
283 virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
284 const ObjCAtSynchronizedStmt &S) = 0;
285 virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF,
286 const ObjCAtTryStmt &S) = 0;
287 virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
288 const ObjCAtThrowStmt &S,
289 bool ClearInsertionPoint=true) = 0;
290 virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
291 Address AddrWeakObj) = 0;
292 virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
293 llvm::Value *src, Address dest) = 0;
294 virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
295 llvm::Value *src, Address dest,
296 bool threadlocal=false) = 0;
297 virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
298 llvm::Value *src, Address dest,
299 llvm::Value *ivarOffset) = 0;
300 virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
301 llvm::Value *src, Address dest) = 0;
302
303 virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
304 QualType ObjectTy,
305 llvm::Value *BaseValue,
306 const ObjCIvarDecl *Ivar,
307 unsigned CVRQualifiers) = 0;
308 virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
309 const ObjCInterfaceDecl *Interface,
310 const ObjCIvarDecl *Ivar) = 0;
311 virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
312 Address DestPtr,
313 Address SrcPtr,
314 llvm::Value *Size) = 0;
315 virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
316 const CodeGen::CGBlockInfo &blockInfo) = 0;
317 virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
318 const CodeGen::CGBlockInfo &blockInfo) = 0;
319 virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM,
320 const CGBlockInfo &blockInfo) {
321 return {};
322 }
323
324 /// Returns an i8* which points to the byref layout information.
325 virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
326 QualType T) = 0;
327
328 struct MessageSendInfo {
329 const CGFunctionInfo &CallInfo;
330 llvm::PointerType *MessengerType;
331
332 MessageSendInfo(const CGFunctionInfo &callInfo,
333 llvm::PointerType *messengerType)
334 : CallInfo(callInfo), MessengerType(messengerType) {}
335 };
336
337 MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
338 QualType resultType,
339 CallArgList &callArgs);
340
341 // FIXME: This probably shouldn't be here, but the code to compute
342 // it is here.
343 unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM,
344 const ObjCInterfaceDecl *ID,
345 const ObjCIvarDecl *Ivar);
346};
347
348/// Creates an instance of an Objective-C runtime class.
349//TODO: This should include some way of selecting which runtime to target.
350CGObjCRuntime *CreateGNUObjCRuntime(CodeGenModule &CGM);
351CGObjCRuntime *CreateMacObjCRuntime(CodeGenModule &CGM);
352}
353}
354#endif
355