lib/CodeGen/CGObjCRuntime.h

//===----- CGObjCRuntime.h - Interface to ObjC Runtimes ---------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This provides an abstract class for Objective-C code generation.  Concrete
// subclasses of this implement code generation for specific Objective-C
// runtime libraries.
//
//===----------------------------------------------------------------------===//

#ifndef CLANG_CODEGEN_OBCJRUNTIME_H
#define CLANG_CODEGEN_OBCJRUNTIME_H
#include "clang/Basic/IdentifierTable.h" // Selector
#include "llvm/ADT/SmallVector.h"
#include <string>

#include "CGBuilder.h"
#include "CGCall.h"
#include "CGValue.h"

namespace llvm {
  class Constant;
  class Function;
  class Module;
  class StructLayout;
  class Type;
  class Value;
}

namespace clang {
namespace CodeGen {
  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;

namespace CodeGen {
  class CodeGenModule;

//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:
  // 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!
  uint64_t ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
                                 const ObjCInterfaceDecl *OID,
                                 const ObjCIvarDecl *Ivar);

  LValue EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
                                  const ObjCInterfaceDecl *OID,
                                  llvm::Value *BaseValue,
                                  const ObjCIvarDecl *Ivar,
                                  unsigned CVRQualifiers,
                                  llvm::Value *Offset);  

public:
  virtual ~CGObjCRuntime();

  /// 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
  /// return value should have the LLVM type for pointer-to
  /// ASTContext::getObjCSelType().
  virtual llvm::Value *GetSelector(CGBuilderTy &Builder,
                                   Selector Sel) = 0;

  /// Generate a constant string object.
  virtual llvm::Constant *GenerateConstantString(const ObjCStringLiteral *) = 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 stucture for this class.
  virtual void GenerateClass(const ObjCImplementationDecl *OID) = 0;
  
  /// Generate an Objective-C message send operation.
  virtual CodeGen::RValue 
  GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
                      QualType ResultType,
                      Selector Sel,
                      llvm::Value *Receiver,
                      bool IsClassMessage,
                      const CallArgList &CallArgs) = 0;

  /// Generate an Objective-C message send operation to the super
  /// class initiated in a method for Class and with the given Self
  /// object.
  virtual CodeGen::RValue
  GenerateMessageSendSuper(CodeGen::CodeGenFunction &CGF,
                           QualType ResultType,
                           Selector Sel,
                           const ObjCInterfaceDecl *Class,
                           bool isCategoryImpl,
                           llvm::Value *Self,
                           bool IsClassMessage,
                           const CallArgList &CallArgs) = 0;

  /// Emit the code to return the named protocol as an object, as in a
  /// @protocol expression.
  virtual llvm::Value *GenerateProtocolRef(CGBuilderTy &Builder,
                                           const ObjCProtocolDecl *OPD) = 0;

  /// Generate the named protocol.  Protocols contain method metadata but no 
  /// implementations. 
  virtual void GenerateProtocol(const ObjCProtocolDecl *OPD) = 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;

  /// Return the runtime function for getting properties.
  virtual llvm::Constant *GetPropertyGetFunction() = 0;
  
  /// Return the runtime function for setting properties.
  virtual llvm::Constant *GetPropertySetFunction() = 0;

  /// GetClass - Return a reference to the class for the given
  /// interface decl.
  virtual llvm::Value *GetClass(CGBuilderTy &Builder, 
                                const ObjCInterfaceDecl *OID) = 0;

  /// EnumerationMutationFunction - Return the function that's called by the
  /// compiler when a mutation is detected during foreach iteration.
  virtual llvm::Constant *EnumerationMutationFunction() = 0;
  
  virtual void EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
                                         const Stmt &S) = 0;
  virtual void EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
                             const ObjCAtThrowStmt &S) = 0;
  virtual llvm::Value *EmitObjCWeakRead(CodeGen::CodeGenFunction &CGF,
                                        llvm::Value *AddrWeakObj) = 0;
  virtual void EmitObjCWeakAssign(CodeGen::CodeGenFunction &CGF,
                                  llvm::Value *src, llvm::Value *dest) = 0;
  virtual void EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
                                    llvm::Value *src, llvm::Value *dest) = 0;
  virtual void EmitObjCIvarAssign(CodeGen::CodeGenFunction &CGF,
                                  llvm::Value *src, llvm::Value *dest) = 0;
  virtual void EmitObjCStrongCastAssign(CodeGen::CodeGenFunction &CGF,
                                        llvm::Value *src, llvm::Value *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;
};

/// 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);
CGObjCRuntime *CreateMacNonFragileABIObjCRuntime(CodeGenModule &CGM);
}
}
#endif