path: root/lib/CodeGen/CodeGenFunction.h

//===-- CodeGenFunction.h - Per-Function state for LLVM CodeGen -*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is the internal per-function state used for llvm translation.
//
//===----------------------------------------------------------------------===//

#ifndef CLANG_CODEGEN_CODEGENFUNCTION_H
#define CLANG_CODEGEN_CODEGENFUNCTION_H

#include "clang/AST/Type.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/ValueHandle.h"
#include <map>
#include "CodeGenModule.h"
#include "CGBlocks.h"
#include "CGBuilder.h"
#include "CGCall.h"
#include "CGCXX.h"
#include "CGValue.h"

namespace llvm {
  class BasicBlock;
  class LLVMContext;
  class Module;
  class SwitchInst;
  class Value;
}

namespace clang {
  class ASTContext;
  class CXXDestructorDecl;
  class Decl;
  class EnumConstantDecl;
  class FunctionDecl;
  class FunctionProtoType;
  class LabelStmt;
  class ObjCContainerDecl;
  class ObjCInterfaceDecl;
  class ObjCIvarDecl;
  class ObjCMethodDecl;
  class ObjCImplementationDecl;
  class ObjCPropertyImplDecl;
  class TargetInfo;
  class VarDecl;
  class ObjCForCollectionStmt;
  class ObjCAtTryStmt;
  class ObjCAtThrowStmt;
  class ObjCAtSynchronizedStmt;

namespace CodeGen {
  class CodeGenModule;
  class CodeGenTypes;
  class CGDebugInfo;
  class CGFunctionInfo;
  class CGRecordLayout;

/// CodeGenFunction - This class organizes the per-function state that is used
/// while generating LLVM code.
class CodeGenFunction : public BlockFunction {
  CodeGenFunction(const CodeGenFunction&); // DO NOT IMPLEMENT
  void operator=(const CodeGenFunction&);  // DO NOT IMPLEMENT
public:
  CodeGenModule &CGM;  // Per-module state.
  TargetInfo &Target;

  typedef std::pair<llvm::Value *, llvm::Value *> ComplexPairTy;
  CGBuilderTy Builder;

  /// CurFuncDecl - Holds the Decl for the current function or ObjC method.
  /// This excludes BlockDecls.
  const Decl *CurFuncDecl;
  /// CurCodeDecl - This is the inner-most code context, which includes blocks.
  const Decl *CurCodeDecl;
  const CGFunctionInfo *CurFnInfo;
  QualType FnRetTy;
  llvm::Function *CurFn;

  /// ReturnBlock - Unified return block.
  llvm::BasicBlock *ReturnBlock;
  /// ReturnValue - The temporary alloca to hold the return value. This is null
  /// iff the function has no return value.
  llvm::Instruction *ReturnValue;

  /// AllocaInsertPoint - This is an instruction in the entry block before which
  /// we prefer to insert allocas.
  llvm::AssertingVH<llvm::Instruction> AllocaInsertPt;

  const llvm::Type *LLVMIntTy;
  uint32_t LLVMPointerWidth;

public:
  /// ObjCEHValueStack - Stack of Objective-C exception values, used for
  /// rethrows.
  llvm::SmallVector<llvm::Value*, 8> ObjCEHValueStack;

  /// PushCleanupBlock - Push a new cleanup entry on the stack and set the
  /// passed in block as the cleanup block.
  void PushCleanupBlock(llvm::BasicBlock *CleanupBlock);

  /// CleanupBlockInfo - A struct representing a popped cleanup block.
  struct CleanupBlockInfo {
    /// CleanupBlock - the cleanup block
    llvm::BasicBlock *CleanupBlock;

    /// SwitchBlock - the block (if any) containing the switch instruction used
    /// for jumping to the final destination.
    llvm::BasicBlock *SwitchBlock;

    /// EndBlock - the default destination for the switch instruction.
    llvm::BasicBlock *EndBlock;

    CleanupBlockInfo(llvm::BasicBlock *cb, llvm::BasicBlock *sb,
                     llvm::BasicBlock *eb)
      : CleanupBlock(cb), SwitchBlock(sb), EndBlock(eb) {}
  };

  /// PopCleanupBlock - Will pop the cleanup entry on the stack, process all
  /// branch fixups and return a block info struct with the switch block and end
  /// block.
  CleanupBlockInfo PopCleanupBlock();

  /// CleanupScope - RAII object that will create a cleanup block and set the
  /// insert point to that block. When destructed, it sets the insert point to
  /// the previous block and pushes a new cleanup entry on the stack.
  class CleanupScope {
    CodeGenFunction& CGF;
    llvm::BasicBlock *CurBB;
    llvm::BasicBlock *CleanupBB;

  public:
    CleanupScope(CodeGenFunction &cgf)
      : CGF(cgf), CurBB(CGF.Builder.GetInsertBlock()) {
      CleanupBB = CGF.createBasicBlock("cleanup");
      CGF.Builder.SetInsertPoint(CleanupBB);
    }

    ~CleanupScope() {
      CGF.PushCleanupBlock(CleanupBB);
      // FIXME: This is silly, move this into the builder.
      if (CurBB)
        CGF.Builder.SetInsertPoint(CurBB);
      else
        CGF.Builder.ClearInsertionPoint();
    }
  };

  /// EmitCleanupBlocks - Takes the old cleanup stack size and emits the cleanup
  /// blocks that have been added.
  void EmitCleanupBlocks(size_t OldCleanupStackSize);