// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#ifndef VM_FLOW_GRAPH_COMPILER_H_
#define VM_FLOW_GRAPH_COMPILER_H_

#include "vm/allocation.h"
#include "vm/assembler.h"
#include "vm/assembler_macros.h"
#include "vm/code_descriptors.h"
#include "vm/code_generator.h"
#include "vm/intermediate_language.h"

namespace dart {

// Forward declarations.
class FlowGraphCompiler;
class DeoptInfoBuilder;

class ParallelMoveResolver : public ValueObject {
 public:
  explicit ParallelMoveResolver(FlowGraphCompiler* compiler);

  // Resolve a set of parallel moves, emitting assembler instructions.
  void EmitNativeCode(ParallelMoveInstr* parallel_move);

 private:
  // Build the initial list of moves.
  void BuildInitialMoveList(ParallelMoveInstr* parallel_move);

  // Perform the move at the moves_ index in question (possibly requiring
  // other moves to satisfy dependencies).
  void PerformMove(int index);

  // Emit a move and remove it from the move graph.
  void EmitMove(int index);

  // Execute a move by emitting a swap of two operands.  The move from
  // source to destination is removed from the move graph.
  void EmitSwap(int index);

  // Verify the move list before performing moves.
  void Verify();

  // Helpers for non-trivial source-destination combinations that cannot
  // be handled by a single instruction.
  void MoveMemoryToMemory(const Address& dst, const Address& src);
  void StoreObject(const Address& dst, const Object& obj);
  void Exchange(Register reg, const Address& mem);
  void Exchange(const Address& mem1, const Address& mem2);

  FlowGraphCompiler* compiler_;

  // List of moves not yet resolved.
  GrowableArray<MoveOperands*> moves_;
};


// Used for describing a deoptimization point after call (lazy deoptimization).
// For deoptimization before instruction use class CompilerDeoptInfoWithStub.
class CompilerDeoptInfo : public ZoneAllocated {
 public:
  CompilerDeoptInfo(intptr_t deopt_id, DeoptReasonId reason)
      : pc_offset_(-1),
        deopt_id_(deopt_id),
        reason_(reason),
        deoptimization_env_(NULL) {}

  RawDeoptInfo* CreateDeoptInfo(FlowGraphCompiler* compiler);

  void AllocateIncomingParametersRecursive(Environment* env,
                                           intptr_t* stack_height);

  // No code needs to be generated.
  virtual void GenerateCode(FlowGraphCompiler* compiler, intptr_t stub_ix) {}

  // Builds deopt-after continuation point.
  virtual void BuildReturnAddress(DeoptInfoBuilder* builder,
                                  const Function& function,
                                  intptr_t slot_ix);

  intptr_t pc_offset() const { return pc_offset_; }
  void set_pc_offset(intptr_t offset) { pc_offset_ = offset; }

  intptr_t deopt_id() const { return deopt_id_; }

  DeoptReasonId reason() const { return reason_; }

  const Environment* deoptimization_env() const { return deoptimization_env_; }
  void set_deoptimization_env(Environment* env) { deoptimization_env_ = env; }

 private:
  intptr_t pc_offset_;
  const intptr_t deopt_id_;
  const DeoptReasonId reason_;
  Environment* deoptimization_env_;

  DISALLOW_COPY_AND_ASSIGN(CompilerDeoptInfo);
};


class CompilerDeoptInfoWithStub : public CompilerDeoptInfo {
 public:
  CompilerDeoptInfoWithStub(intptr_t deopt_id,
                            DeoptReasonId reason)
      : CompilerDeoptInfo(deopt_id, reason), entry_label_() {
    ASSERT(reason != kDeoptAtCall);
  }

  Label* entry_label() { return &entry_label_; }

  // Implementation is in architecture specific file.
  virtual void GenerateCode(FlowGraphCompiler* compiler, intptr_t stub_ix);

  // Builds deopt-before continuation point.
  virtual void BuildReturnAddress(DeoptInfoBuilder* builder,
                                  const Function& function,
                                  intptr_t slot_ix);

 private:
  Label entry_label_;

  DISALLOW_COPY_AND_ASSIGN(CompilerDeoptInfoWithStub);
};


class SlowPathCode : public ZoneAllocated {
 public:
  SlowPathCode() : entry_label_(), exit_label_() { }

  Label* entry_label() { return &entry_label_; }
  Label* exit_label() { return &exit_label_; }

  virtual void EmitNativeCode(FlowGraphCompiler* compiler) = 0;

 private:
  Label entry_label_;
  Label exit_label_;

  DISALLOW_COPY_AND_ASSIGN(SlowPathCode);
};


}  // namespace dart

#if defined(TARGET_ARCH_IA32)
#include "vm/flow_graph_compiler_ia32.h"
#elif defined(TARGET_ARCH_X64)
#include "vm/flow_graph_compiler_x64.h"
#elif defined(TARGET_ARCH_ARM)
#include "vm/flow_graph_compiler_arm.h"
#else
#error Unknown architecture.
#endif

#endif  // VM_FLOW_GRAPH_COMPILER_H_