//===----- CGObjCRuntime.h - Interface to ObjC Runtimes ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This provides an abstract class for Objective-C code generation. Concrete
// subclasses of this implement code generation for specific Objective-C
// runtime libraries.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H
#define LLVM_CLANG_LIB_CODEGEN_CGOBJCRUNTIME_H
#include "CGBuilder.h"
#include "CGCall.h"
#include "CGCleanup.h"
#include "CGValue.h"
#include "clang/AST/DeclObjC.h"
#include "clang/Basic/IdentifierTable.h" // Selector
#include "llvm/ADT/UniqueVector.h"
namespace llvm {
class Constant;
class Function;
class Module;
class StructLayout;
class StructType;
class Type;
class Value;
}
namespace clang {
namespace CodeGen {
class CGFunctionInfo;
class CodeGenFunction;
}
class FieldDecl;
class ObjCAtTryStmt;
class ObjCAtThrowStmt;
class ObjCAtSynchronizedStmt;
class ObjCContainerDecl;
class ObjCCategoryImplDecl;
class ObjCImplementationDecl;
class ObjCInterfaceDecl;
class ObjCMessageExpr;
class ObjCMethodDecl;
class ObjCProtocolDecl;
class Selector;
class ObjCIvarDecl;
class ObjCStringLiteral;
class BlockDeclRefExpr;
namespace CodeGen {
class CodeGenModule;
class CGBlockInfo;
// FIXME: Several methods should be pure virtual but aren't to avoid the
// partially-implemented subclass breaking.
/// Implements runtime-specific code generation functions.
class CGObjCRuntime {
protected:
CodeGen::CodeGenModule &CGM;
CGObjCRuntime(CodeGen::CodeGenModule &CGM) : CGM(CGM) {}
// Utility functions for unified ivar access. These need to
// eventually be folded into other places (the structure layout
// code).
/// Compute an offset to the given ivar, suitable for passing to
/// EmitValueForIvarAtOffset. Note that the correct handling of
/// bit-fields is carefully coordinated by these two, use caution!
///
/// The latter overload is suitable for computing the offset of a
/// sythesized ivar.
uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
const ObjCInterfaceDecl *OID,
const ObjCIvarDecl *Ivar);
uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
const ObjCImplementationDecl *OID,
const ObjCIvarDecl *Ivar);
LValue EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
const ObjCInterfaceDecl *OID,
llvm::Value *BaseValue,
const ObjCIvarDecl *Ivar,
unsigned CVRQualifiers,
llvm::Value *Offset);
/// Emits a try / catch statement. This function is intended to be called by
/// subclasses, and provides a generic mechanism for generating these, which
/// should be usable by all runtimes. The caller must provide the functions
/// to call when entering and exiting a \@catch() block, and the function
/// used to rethrow exceptions. If the begin and end catch functions are
/// NULL, then the function assumes that the EH personality function provides
/// the thrown object directly.
void EmitTryCatchStmt(CodeGenFunction &CGF, const ObjCAtTryStmt &S,
llvm::FunctionCallee beginCatchFn,
llvm::FunctionCallee endCatchFn,
llvm::FunctionCallee exceptionRethrowFn);
void EmitInitOfCatchParam(CodeGenFunction &CGF, llvm::Value *exn,
const VarDecl *paramDecl);
/// Emits an \@synchronize() statement, using the \p syncEnterFn and
/// \p syncExitFn arguments as the functions called to lock and unlock
/// the object. This function can be called by subclasses that use
/// zero-cost exception handling.
void EmitAtSynchronizedStmt(CodeGenFunction &CGF,
const ObjCAtSynchronizedStmt &S,
llvm::FunctionCallee syncEnterFn,
llvm::FunctionCallee syncExitFn);
public:
virtual ~CGObjCRuntime();
std::string getSymbolNameForMethod(const ObjCMethodDecl *method,
bool includeCategoryName = true);
/// Generate the function required to register all Objective-C components in
/// this compilation unit with the runtime library.
virtual llvm::Function *ModuleInitFunction() = 0;
/// Get a selector for the specified name and type values.
/// The result should have the LLVM type for ASTContext::getObjCSelType().
virtual llvm::Value *GetSelector(CodeGenFunction &CGF, Selector Sel) = 0;
/// Get the address of a selector for the specified name and type values.
/// This is a rarely-used language extension, but sadly it exists.
///
/// The result should have the LLVM type for a pointer to
/// ASTContext::getObjCSelType().
virtual Address GetAddrOfSelector(CodeGenFunction &CGF, Selector Sel) = 0;
/// Get a typed selector.
virtual llvm::Value *GetSelector(CodeGenFunction &CGF,
const ObjCMethodDecl *Method) = 0;
/// Get the type constant to catch for the given ObjC pointer type.
/// This is used externally to implement catching ObjC types in C++.
/// Runtimes which don't support this should add the appropriate
/// error to Sema.
virtual llvm::Constant *GetEHType(QualType T) = 0;
virtual CatchTypeInfo getCatchAllTypeInfo() { return { nullptr, 0 }; }
/// Generate a constant string object.
virtual ConstantAddress GenerateConstantString(const StringLiteral *) = 0;
/// Generate a category. A category contains a list of methods (and
/// accompanying metadata) and a list of protocols.
virtual void GenerateCategory(const ObjCCategoryImplDecl *OCD) = 0;
/// Generate a class structure for this class.
virtual void GenerateClass(const ObjCImplementationDecl *OID) = 0;
/// Register an class alias.
virtual void RegisterAlias(const ObjCCompatibleAliasDecl *OAD) = 0;
/// Generate an Objective-C message send operation.
///
/// \param Method - The method being called, this may be null if synthesizing
/// a property setter or getter.
virtual CodeGen::RValue
GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
ReturnValueSlot ReturnSlot,
QualType ResultType,
Selector Sel,
llvm::Value *Receiver,
const CallArgList &CallArgs,
const ObjCInterfaceDecl *Class = nullptr,
const ObjCMethodDecl *Method = nullptr) = 0;
/// Generate an Objective-C message send operation.
///
/// This variant allows for the call to be substituted with an optimized
/// variant.
CodeGen::RValue
GeneratePossiblySpecializedMessageSend(CodeGenFunction &CGF,
ReturnValueSlot Return,
QualType ResultType,
Selector Sel,
llvm::Value *Receiver,
const CallArgList& Args,
const ObjCInterfaceDecl *OID,
const ObjCMethodDecl *Method,
bool isClassMessage);
/// Generate an Objective-C message send operation to the super
/// class initiated in a method for Class and with the given Self
/// object.
///
/// \param Method - The method being called, this may be null if synthesizing
/// a property setter or getter.
virtual CodeGen::RValue
GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
ReturnValueSlot ReturnSlot,
QualType ResultType,
Selector Sel,
const ObjCInterfaceDecl *Class,
bool isCategoryImpl,
llvm::Value *Self,
bool IsClassMessage,
const CallArgList &CallArgs,
const ObjCMethodDecl *Method = nullptr) = 0;
/// Walk the list of protocol references from a class, category or
/// protocol to traverse the DAG formed from it's inheritance hierarchy. Find
/// the list of protocols that ends each walk at either a runtime
/// protocol or a non-runtime protocol with no parents. For the common case of
/// just a list of standard runtime protocols this just returns the same list
/// that was passed in.
std::vector<const ObjCProtocolDecl *>
GetRuntimeProtocolList(ObjCProtocolDecl::protocol_iterator begin,
ObjCProtocolDecl::protocol_iterator end);
/// Emit the code to return the named protocol as an object, as in a
/// \@protocol expression.
virtual llvm::Value *GenerateProtocolRef(CodeGenFunction &CGF,
const ObjCProtocolDecl *OPD) = 0;
/// Generate the named protocol. Protocols contain method metadata but no
/// implementations.
virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 0;
/// GetOrEmitProtocol - Get the protocol object for the given
/// declaration, emitting it if necessary. The return value has type
/// ProtocolPtrTy.
virtual llvm::Constant *GetOrEmitProtocol(const ObjCProtocolDecl *PD) = 0;
/// Generate a function preamble for a method with the specified
/// types.
// FIXME: Current this just generates the Function definition, but really this
// should also be generating the loads of the parameters, as the runtime
// should have full control over how parameters are passed.
virtual llvm::Function *GenerateMethod(const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD) = 0;
/// Generates prologue for direct Objective-C Methods.
virtual void GenerateDirectMethodPrologue(CodeGenFunction &CGF,
llvm::Function *Fn,
const ObjCMethodDecl *OMD,
const ObjCContainerDecl *CD) = 0;
/// Return the runtime function for getting properties.
virtual llvm::FunctionCallee GetPropertyGetFunction() = 0;
/// Return the runtime function for setting properties.
virtual llvm::FunctionCallee GetPropertySetFunction() = 0;
/// Return the runtime function for optimized setting properties.
virtual llvm::FunctionCallee GetOptimizedPropertySetFunction(bool atomic,
bool copy) = 0;
// API for atomic copying of qualified aggregates in getter.
virtual llvm::FunctionCallee GetGetStructFunction() = 0;
// API for atomic copying of qualified aggregates in setter.
virtual llvm::FunctionCallee GetSetStructFunction() = 0;
/// API for atomic copying of qualified aggregates with non-trivial copy
/// assignment (c++) in setter.
virtual llvm::FunctionCallee GetCppAtomicObjectSetFunction() = 0;
/// API for atomic copying of qualified aggregates with non-trivial copy
/// assignment (c++) in getter.
virtual llvm::FunctionCallee GetCppAtomicObjectGetFunction() = 0;
/// GetClass - Return a reference to the class for the given
/// interface decl.
virtual llvm::Value *GetClass(CodeGenFunction &CGF,
const ObjCInterfaceDecl *OID) = 0;
virtual llvm::Value *EmitNSAutoreleasePoolClassRef(CodeGenFunction &CGF) {
llvm_unreachable("autoreleasepool unsupported in this ABI");
}
/// EnumerationMutationFunction - Return the function that's called by the
/// compiler when a mutation is detected during foreach iteration.
virtual llvm::FunctionCallee EnumerationMutationFunction() = 0;
virtual void EmitSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtSynchronizedStmt &S) = 0;
virtual void EmitTryStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtTryStmt &S) = 0;
virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtThrowStmt &S,
bool ClearInsertionPoint=true) = 0;
virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
Address AddrWeakObj) = 0;
virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, Address dest) = 0;
virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, Address dest,
bool threadlocal=false) = 0;
virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, Address dest,
llvm::Value *ivarOffset) = 0;
virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
llvm::Value *src, Address dest) = 0;
virtual LValue EmitObjCValueForIvar(CodeGen::CodeGenFunction &CGF,
QualType ObjectTy,
llvm::Value *BaseValue,
const ObjCIvarDecl *Ivar,
unsigned CVRQualifiers) = 0;
virtual llvm::Value *EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
const ObjCInterfaceDecl *Interface,
const ObjCIvarDecl *Ivar) = 0;
virtual void EmitGCMemmoveCollectable(CodeGen::CodeGenFunction &CGF,
Address DestPtr,
Address SrcPtr,
llvm::Value *Size) = 0;
virtual llvm::Constant *BuildGCBlockLayout(CodeGen::CodeGenModule &CGM,
const CodeGen::CGBlockInfo &blockInfo) = 0;
virtual llvm::Constant *BuildRCBlockLayout(CodeGen::CodeGenModule &CGM,
const CodeGen::CGBlockInfo &blockInfo) = 0;
virtual std::string getRCBlockLayoutStr(CodeGen::CodeGenModule &CGM,
const CGBlockInfo &blockInfo) {
return {};
}
/// Returns an i8* which points to the byref layout information.
virtual llvm::Constant *BuildByrefLayout(CodeGen::CodeGenModule &CGM,
QualType T) = 0;
struct MessageSendInfo {
const CGFunctionInfo &CallInfo;
llvm::PointerType *MessengerType;
MessageSendInfo(const CGFunctionInfo &callInfo,
llvm::PointerType *messengerType)
: CallInfo(callInfo), MessengerType(messengerType) {}
};
MessageSendInfo getMessageSendInfo(const ObjCMethodDecl *method,
QualType resultType,
CallArgList &callArgs);
bool canMessageReceiverBeNull(CodeGenFunction &CGF,
const ObjCMethodDecl *method,
bool isSuper,
const ObjCInterfaceDecl *classReceiver,
llvm::Value *receiver);
static bool isWeakLinkedClass(const ObjCInterfaceDecl *cls);
/// Destroy the callee-destroyed arguments of the given method,
/// if it has any. Used for nil-receiver paths in message sends.
/// Never does anything if the method does not satisfy
/// hasParamDestroyedInCallee().
///
/// \param callArgs - just the formal arguments, not including implicit
/// arguments such as self and cmd
static void destroyCalleeDestroyedArguments(CodeGenFunction &CGF,
const ObjCMethodDecl *method,
const CallArgList &callArgs);
// FIXME: This probably shouldn't be here, but the code to compute
// it is here.
unsigned ComputeBitfieldBitOffset(CodeGen::CodeGenModule &CGM,
const ObjCInterfaceDecl *ID,
const ObjCIvarDecl *Ivar);
};
/// Creates an instance of an Objective-C runtime class.
//TODO: This should include some way of selecting which runtime to target.
CGObjCRuntime *CreateGNUObjCRuntime(CodeGenModule &CGM);
CGObjCRuntime *CreateMacObjCRuntime(CodeGenModule &CGM);
}
}
#endif
