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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-exception6//7//===----------------------------------------------------------------------===//8//9// This provides an abstract class for Objective-C code generation. Concrete10// subclasses of this implement code generation for specific Objective-C11// runtime libraries.12//13//===----------------------------------------------------------------------===//14 15#ifndef LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H16#define LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H17#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" // Selector23#include "llvm/ADT/UniqueVector.h"24 25namespace llvm {26class Constant;27class Function;28class Module;29class StructLayout;30class StructType;31class Type;32class Value;33} // namespace llvm34 35namespace clang {36namespace CodeGen {37class CGFunctionInfo;38class CodeGenFunction;39} // namespace CodeGen40 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 the62// 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 to71 // eventually be folded into other places (the structure layout72 // code).73 74 /// Compute an offset to the given ivar, suitable for passing to75 /// EmitValueForIvarAtOffset. Note that the correct handling of76 /// bit-fields is carefully coordinated by these two, use caution!77 ///78 /// The latter overload is suitable for computing the offset of a79 /// 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 by93 /// subclasses, and provides a generic mechanism for generating these, which94 /// should be usable by all runtimes. The caller must provide the functions95 /// to call when entering and exiting a \@catch() block, and the function96 /// used to rethrow exceptions. If the begin and end catch functions are97 /// NULL, then the function assumes that the EH personality function provides98 /// 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 and108 /// \p syncExitFn arguments as the functions called to lock and unlock109 /// the object. This function can be called by subclasses that use110 /// 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 in123 /// 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 to134 /// 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 appropriate144 /// 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 (and153 /// 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 synthesizing165 /// a property setter or getter.166 virtual CodeGen::RValue167 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 optimized176 /// 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 super184 /// class initiated in a method for Class and with the given Self185 /// object.186 ///187 /// \param Method - The method being called, this may be null if synthesizing188 /// 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 or196 /// protocol to traverse the DAG formed from it's inheritance hierarchy. Find197 /// the list of protocols that ends each walk at either a runtime198 /// protocol or a non-runtime protocol with no parents. For the common case of199 /// just a list of standard runtime protocols this just returns the same list200 /// 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 a206 /// \@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 no211 /// implementations.212 virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;213 214 /// GetOrEmitProtocol - Get the protocol object for the given215 /// declaration, emitting it if necessary. The return value has type216 /// ProtocolPtrTy.217 virtual llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) = 0;218 219 /// Generate a function preamble for a method with the specified220 /// types.221 222 // FIXME: Current this just generates the Function definition, but really this223 // should also be generating the loads of the parameters, as the runtime224 // 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 copy249 /// assignment (c++) in setter.250 virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0;251 /// API for atomic copying of qualified aggregates with non-trivial copy252 /// assignment (c++) in getter.253 virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0;254 255 /// GetClass - Return a reference to the class for the given256 /// 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 the265 /// 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 satisfy334 /// hasParamDestroyedInCallee().335 ///336 /// \param callArgs - just the formal arguments, not including implicit337 /// arguments such as self and cmd338 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 compute343 // 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 CodeGen354} // namespace clang355#endif356