sdk/runtime/vm/flow_graph_optimizer.h

// 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_OPTIMIZER_H_
#define VM_FLOW_GRAPH_OPTIMIZER_H_

#include "vm/intermediate_language.h"
#include "vm/flow_graph.h"

namespace dart {

template <typename T> class GrowableArray;
template <typename T> class DirectChainedHashMap;

class FlowGraphOptimizer : public FlowGraphVisitor {
 public:
  explicit FlowGraphOptimizer(FlowGraph* flow_graph)
      : FlowGraphVisitor(flow_graph->reverse_postorder()),
        flow_graph_(flow_graph) { }
  virtual ~FlowGraphOptimizer() {}

  void ApplyICData();

  void OptimizeComputations();

  void EliminateDeadPhis();

  void SelectRepresentations();

  virtual void VisitStaticCall(StaticCallComp* comp, BindInstr* instr);
  virtual void VisitInstanceCall(InstanceCallComp* comp, BindInstr* instr);
  virtual void VisitRelationalOp(RelationalOpComp* comp, BindInstr* instr);
  virtual void VisitEqualityCompare(EqualityCompareComp* comp,
                                    BindInstr* instr);
  virtual void VisitBind(BindInstr* instr);
  virtual void VisitBranch(BranchInstr* instr);

  // TODO(fschneider): Once we get rid of the distinction between Instruction
  // and computation, this can be made private again.
  BindInstr* InsertBefore(Instruction* instr,
                          Computation* comp,
                          Environment* env,
                          BindInstr::UseKind use_kind);

 private:
  bool TryReplaceWithArrayOp(BindInstr* instr,
                             InstanceCallComp* comp,
                             Token::Kind op_kind);
  bool TryReplaceWithBinaryOp(BindInstr* instr,
                              InstanceCallComp* comp,
                              Token::Kind op_kind);
  bool TryReplaceWithUnaryOp(BindInstr* instr,
                             InstanceCallComp* comp,
                             Token::Kind op_kind);

  bool TryInlineInstanceGetter(BindInstr* instr,
                               InstanceCallComp* comp);
  bool TryInlineInstanceSetter(BindInstr* instr, InstanceCallComp* comp);

  bool TryInlineInstanceMethod(BindInstr* instr, InstanceCallComp* comp);

  void AddCheckClass(BindInstr* instr, InstanceCallComp* comp, Value* value);

  BindInstr* InsertAfter(Instruction* instr,
                         Computation* comp,
                         Environment* env,
                         BindInstr::UseKind use_kind);

  void InsertConversionsFor(Definition* def);

  FlowGraph* flow_graph_;

  DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
};


// Analyze the generated flow graph. Currently only if it is a leaf
// method, i.e., does not contain any calls to runtime or other Dart code.
class FlowGraphAnalyzer : public ValueObject {
 public:
  explicit FlowGraphAnalyzer(const FlowGraph& flow_graph)
      : blocks_(flow_graph.reverse_postorder()), is_leaf_(false) {}
  virtual ~FlowGraphAnalyzer() {}

  void Analyze();

  bool is_leaf() const { return is_leaf_; }

 private:
  const GrowableArray<BlockEntryInstr*>& blocks_;
  bool is_leaf_;

  DISALLOW_COPY_AND_ASSIGN(FlowGraphAnalyzer);
};


class ParsedFunction;


class FlowGraphTypePropagator : public FlowGraphVisitor {
 public:
  explicit FlowGraphTypePropagator(const FlowGraph& flow_graph)
      : FlowGraphVisitor(flow_graph.reverse_postorder()),
        parsed_function_(flow_graph.parsed_function()),
        still_changing_(false) { }
  virtual ~FlowGraphTypePropagator() { }

  const ParsedFunction& parsed_function() const { return parsed_function_; }

  void PropagateTypes();

  virtual void VisitAssertAssignable(AssertAssignableComp* comp,
                                     BindInstr* instr);
  virtual void VisitAssertBoolean(AssertBooleanComp* comp, BindInstr* instr);
  virtual void VisitInstanceOf(InstanceOfComp* comp, BindInstr* instr);

  virtual void VisitGraphEntry(GraphEntryInstr* graph_entry);
  virtual void VisitJoinEntry(JoinEntryInstr* join_entry);
  virtual void VisitBind(BindInstr* bind);
  virtual void VisitPhi(PhiInstr* phi);
  virtual void VisitParameter(ParameterInstr* param);
  virtual void VisitPushArgument(PushArgumentInstr* bind);

 private:
  const ParsedFunction& parsed_function_;
  bool still_changing_;
  DISALLOW_COPY_AND_ASSIGN(FlowGraphTypePropagator);
};


// A simple common subexpression elimination based
// on the dominator tree.
class DominatorBasedCSE : public AllStatic {
 public:
  static void Optimize(BlockEntryInstr* graph_entry);

 private:
  static void OptimizeRecursive(
      BlockEntryInstr* entry,
      DirectChainedHashMap<BindInstr*>* map);
};


}  // namespace dart

#endif  // VM_FLOW_GRAPH_OPTIMIZER_H_