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. 173 /// 174 /// This variant allows for the call to be substituted with an optimized 175 /// variant. 176 CodeGen::RValue 177 GeneratePossiblySpecializedMessageSend(CodeGenFunction &CGF, 178 ReturnValueSlot Return, 179 QualType ResultType, 180 Selector Sel, 181 llvm::Value *Receiver, 182 const CallArgList& Args, 183 const ObjCInterfaceDecl *OID, 184 const ObjCMethodDecl *Method, 185 bool isClassMessage); 186 187 /// Generate an Objective-C message send operation to the super 188 /// class initiated in a method for Class and with the given Self 189 /// object. 190 /// 191 /// \param Method - The method being called, this may be null if synthesizing 192 /// a property setter or getter. 193 virtual CodeGen::RValue 194 GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF, 195 ReturnValueSlot ReturnSlot, 196 QualType ResultType, 197 Selector Sel, 198 const ObjCInterfaceDecl *Class, 199 bool isCategoryImpl, 200 llvm::Value *Self, 201 bool IsClassMessage, 202 const CallArgList &CallArgs, 203 const ObjCMethodDecl *Method = nullptr) = 0; 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 /// Generate a function preamble for a method with the specified 215 /// types. 216 217 // FIXME: Current this just generates the Function definition, but really this 218 // should also be generating the loads of the parameters, as the runtime 219 // should have full control over how parameters are passed. 220 virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD, 221 const ObjCContainerDecl *CD) = 0; 222 223 /// Generates prologue for direct Objective-C Methods. 224 virtual void GenerateDirectMethodPrologue(CodeGenFunction &CGF, 225 llvm::Function *Fn, 226 const ObjCMethodDecl *OMD, 227 const ObjCContainerDecl *CD) = 0; 228 229 /// Return the runtime function for getting properties. 230 virtual llvm::FunctionCallee GetPropertyGetFunction() = 0; 231 232 /// Return the runtime function for setting properties. 233 virtual llvm::FunctionCallee GetPropertySetFunction() = 0; 234 235 /// Return the runtime function for optimized setting properties. 236 virtual llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic, 237 bool copy) = 0; 238 239 // API for atomic copying of qualified aggregates in getter. 240 virtual llvm::FunctionCallee GetGetStructFunction() = 0; 241 // API for atomic copying of qualified aggregates in setter. 242 virtual llvm::FunctionCallee GetSetStructFunction() = 0; 243 /// API for atomic copying of qualified aggregates with non-trivial copy 244 /// assignment (c++) in setter. 245 virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0; 246 /// API for atomic copying of qualified aggregates with non-trivial copy 247 /// assignment (c++) in getter. 248 virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0; 249 250 /// GetClass - Return a reference to the class for the given 251 /// interface decl. 252 virtual llvm::Value *GetClass(CodeGenFunction &CGF, 253 const ObjCInterfaceDecl *OID) = 0; 254 255 256 virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) { 257 llvm_unreachable("autoreleasepool unsupported in this ABI"); 258 } 259 260 /// EnumerationMutationFunction - Return the function that's called by the 261 /// compiler when a mutation is detected during foreach iteration. 262 virtual llvm::FunctionCallee EnumerationMutationFunction() = 0; 263 264 virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF, 265 const ObjCAtSynchronizedStmt &S) = 0; 266 virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF, 267 const ObjCAtTryStmt &S) = 0; 268 virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF, 269 const ObjCAtThrowStmt &S, 270 bool ClearInsertionPoint=true) = 0; 271 virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF, 272 Address AddrWeakObj) = 0; 273 virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF, 274 llvm::Value *src, Address dest) = 0; 275 virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF, 276 llvm::Value *src, Address dest, 277 bool threadlocal=false) = 0; 278 virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF, 279 llvm::Value *src, Address dest, 280 llvm::Value *ivarOffset) = 0; 281 virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF, 282 llvm::Value *src, Address dest) = 0; 283 284 virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF, 285 QualType ObjectTy, 286 llvm::Value *BaseValue, 287 const ObjCIvarDecl *Ivar, 288 unsigned CVRQualifiers) = 0; 289 virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF, 290 const ObjCInterfaceDecl *Interface, 291 const ObjCIvarDecl *Ivar) = 0; 292 virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF, 293 Address DestPtr, 294 Address SrcPtr, 295 llvm::Value *Size) = 0; 296 virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM, 297 const CodeGen::CGBlockInfo &blockInfo) = 0; 298 virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM, 299 const CodeGen::CGBlockInfo &blockInfo) = 0; 300 virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM, 301 const CGBlockInfo &blockInfo) { 302 return {}; 303 } 304 305 /// Returns an i8* which points to the byref layout information. 306 virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM, 307 QualType T) = 0; 308 309 struct MessageSendInfo { 310 const CGFunctionInfo &CallInfo; 311 llvm::PointerType *MessengerType; 312 313 MessageSendInfo(const CGFunctionInfo &callInfo, 314 llvm::PointerType *messengerType) 315 : CallInfo(callInfo), MessengerType(messengerType) {} 316 }; 317 318 MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method, 319 QualType resultType, 320 CallArgList &callArgs); 321 322 // FIXME: This probably shouldn't be here, but the code to compute 323 // it is here. 324 unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM, 325 const ObjCInterfaceDecl *ID, 326 const ObjCIvarDecl *Ivar); 327 }; 328 329 /// Creates an instance of an Objective-C runtime class. 330 //TODO: This should include some way of selecting which runtime to target. 331 CGObjCRuntime *CreateGNUObjCRuntime(CodeGenModule &CGM); 332 CGObjCRuntime *CreateMacObjCRuntime(CodeGenModule &CGM); 333 } 334 } 335 #endif 336