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