Move class LGapResolver to the platform specific backend implementation files.

This change is in preparation for introducing platform-specific strategies
for resolving parallel moves.

Review URL: http://codereview.chromium.org/6324003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6321 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-codegen-arm.cc

@@ -54,6 +54,157 @@ class SafepointGenerator : public PostCallGenerator {
 };
 
 
+class LGapNode: public ZoneObject {
+ public:
+  explicit LGapNode(LOperand* operand)
+      : operand_(operand), resolved_(false), visited_id_(-1) { }
+
+  LOperand* operand() const { return operand_; }
+  bool IsResolved() const { return !IsAssigned() || resolved_; }
+  void MarkResolved() {
+    ASSERT(!IsResolved());
+    resolved_ = true;
+  }
+  int visited_id() const { return visited_id_; }
+  void set_visited_id(int id) {
+    ASSERT(id > visited_id_);
+    visited_id_ = id;
+  }
+
+  bool IsAssigned() const { return assigned_from_.is_set(); }
+  LGapNode* assigned_from() const { return assigned_from_.get(); }
+  void set_assigned_from(LGapNode* n) { assigned_from_.set(n); }
+
+ private:
+  LOperand* operand_;
+  SetOncePointer<LGapNode> assigned_from_;
+  bool resolved_;
+  int visited_id_;
+};
+
+
+LGapResolver::LGapResolver()
+    : nodes_(32),
+      identified_cycles_(4),
+      result_(16),
+      next_visited_id_(0) {
+}
+
+
+const ZoneList<LMoveOperands>* LGapResolver::Resolve(
+    const ZoneList<LMoveOperands>* moves,
+    LOperand* marker_operand) {
+  nodes_.Rewind(0);
+  identified_cycles_.Rewind(0);
+  result_.Rewind(0);
+  next_visited_id_ = 0;
+
+  for (int i = 0; i < moves->length(); ++i) {
+    LMoveOperands move = moves->at(i);
+    if (!move.IsRedundant()) RegisterMove(move);
+  }
+
+  for (int i = 0; i < identified_cycles_.length(); ++i) {
+    ResolveCycle(identified_cycles_[i], marker_operand);
+  }
+
+  int unresolved_nodes;
+  do {
+    unresolved_nodes = 0;
+    for (int j = 0; j < nodes_.length(); j++) {
+      LGapNode* node = nodes_[j];
+      if (!node->IsResolved() && node->assigned_from()->IsResolved()) {
+        AddResultMove(node->assigned_from(), node);
+        node->MarkResolved();
+      }
+      if (!node->IsResolved()) ++unresolved_nodes;
+    }
+  } while (unresolved_nodes > 0);
+  return &result_;
+}
+
+
+void LGapResolver::AddResultMove(LGapNode* from, LGapNode* to) {
+  AddResultMove(from->operand(), to->operand());
+}
+
+
+void LGapResolver::AddResultMove(LOperand* from, LOperand* to) {
+  result_.Add(LMoveOperands(from, to));
+}
+
+
+void LGapResolver::ResolveCycle(LGapNode* start, LOperand* marker_operand) {
+  ZoneList<LOperand*> cycle_operands(8);
+  cycle_operands.Add(marker_operand);
+  LGapNode* cur = start;
+  do {
+    cur->MarkResolved();
+    cycle_operands.Add(cur->operand());
+    cur = cur->assigned_from();
+  } while (cur != start);
+  cycle_operands.Add(marker_operand);
+
+  for (int i = cycle_operands.length() - 1; i > 0; --i) {
+    LOperand* from = cycle_operands[i];
+    LOperand* to = cycle_operands[i - 1];
+    AddResultMove(from, to);
+  }
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b, int visited_id) {
+  ASSERT(a != b);
+  LGapNode* cur = a;
+  while (cur != b && cur->visited_id() != visited_id && cur->IsAssigned()) {
+    cur->set_visited_id(visited_id);
+    cur = cur->assigned_from();
+  }
+
+  return cur == b;
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b) {
+  ASSERT(a != b);
+  return CanReach(a, b, next_visited_id_++);
+}
+
+
+void LGapResolver::RegisterMove(LMoveOperands move) {
+  if (move.from()->IsConstantOperand()) {
+    // Constant moves should be last in the machine code. Therefore add them
+    // first to the result set.
+    AddResultMove(move.from(), move.to());
+  } else {
+    LGapNode* from = LookupNode(move.from());
+    LGapNode* to = LookupNode(move.to());
+    if (to->IsAssigned() && to->assigned_from() == from) {
+      move.Eliminate();
+      return;
+    }
+    ASSERT(!to->IsAssigned());
+    if (CanReach(from, to)) {
+      // This introduces a cycle. Save.
+      identified_cycles_.Add(from);
+    }
+    to->set_assigned_from(from);
+  }
+}
+
+
+LGapNode* LGapResolver::LookupNode(LOperand* operand) {
+  for (int i = 0; i < nodes_.length(); ++i) {
+    if (nodes_[i]->operand()->Equals(operand)) return nodes_[i];
+  }
+
+  // No node found => create a new one.
+  LGapNode* result = new LGapNode(operand);
+  nodes_.Add(result);
+  return result;
+}
+
+
 #define __ masm()->
 
 bool LCodeGen::GenerateCode() {

src/arm/lithium-codegen-arm.h

@@ -39,8 +39,30 @@ namespace internal {
 
 // Forward declarations.
 class LDeferredCode;
+class LGapNode;
 class SafepointGenerator;
 
+class LGapResolver BASE_EMBEDDED {
+ public:
+  LGapResolver();
+  const ZoneList<LMoveOperands>* Resolve(const ZoneList<LMoveOperands>* moves,
+                                         LOperand* marker_operand);
+
+ private:
+  LGapNode* LookupNode(LOperand* operand);
+  bool CanReach(LGapNode* a, LGapNode* b, int visited_id);
+  bool CanReach(LGapNode* a, LGapNode* b);
+  void RegisterMove(LMoveOperands move);
+  void AddResultMove(LOperand* from, LOperand* to);
+  void AddResultMove(LGapNode* from, LGapNode* to);
+  void ResolveCycle(LGapNode* start, LOperand* marker_operand);
+
+  ZoneList<LGapNode*> nodes_;
+  ZoneList<LGapNode*> identified_cycles_;
+  ZoneList<LMoveOperands> result_;
+  int next_visited_id_;
+};
+
 
 class LCodeGen BASE_EMBEDDED {
  public:

src/ia32/lithium-codegen-ia32.cc

@@ -58,6 +58,157 @@ class SafepointGenerator : public PostCallGenerator {
 };
 
 
+class LGapNode: public ZoneObject {
+ public:
+  explicit LGapNode(LOperand* operand)
+      : operand_(operand), resolved_(false), visited_id_(-1) { }
+
+  LOperand* operand() const { return operand_; }
+  bool IsResolved() const { return !IsAssigned() || resolved_; }
+  void MarkResolved() {
+    ASSERT(!IsResolved());
+    resolved_ = true;
+  }
+  int visited_id() const { return visited_id_; }
+  void set_visited_id(int id) {
+    ASSERT(id > visited_id_);
+    visited_id_ = id;
+  }
+
+  bool IsAssigned() const { return assigned_from_.is_set(); }
+  LGapNode* assigned_from() const { return assigned_from_.get(); }
+  void set_assigned_from(LGapNode* n) { assigned_from_.set(n); }
+
+ private:
+  LOperand* operand_;
+  SetOncePointer<LGapNode> assigned_from_;
+  bool resolved_;
+  int visited_id_;
+};
+
+
+LGapResolver::LGapResolver()
+    : nodes_(32),
+      identified_cycles_(4),
+      result_(16),
+      next_visited_id_(0) {
+}
+
+
+const ZoneList<LMoveOperands>* LGapResolver::Resolve(
+    const ZoneList<LMoveOperands>* moves,
+    LOperand* marker_operand) {
+  nodes_.Rewind(0);
+  identified_cycles_.Rewind(0);
+  result_.Rewind(0);
+  next_visited_id_ = 0;
+
+  for (int i = 0; i < moves->length(); ++i) {
+    LMoveOperands move = moves->at(i);
+    if (!move.IsRedundant()) RegisterMove(move);
+  }
+
+  for (int i = 0; i < identified_cycles_.length(); ++i) {
+    ResolveCycle(identified_cycles_[i], marker_operand);
+  }
+
+  int unresolved_nodes;
+  do {
+    unresolved_nodes = 0;
+    for (int j = 0; j < nodes_.length(); j++) {
+      LGapNode* node = nodes_[j];
+      if (!node->IsResolved() && node->assigned_from()->IsResolved()) {
+        AddResultMove(node->assigned_from(), node);
+        node->MarkResolved();
+      }
+      if (!node->IsResolved()) ++unresolved_nodes;
+    }
+  } while (unresolved_nodes > 0);
+  return &result_;
+}
+
+
+void LGapResolver::AddResultMove(LGapNode* from, LGapNode* to) {
+  AddResultMove(from->operand(), to->operand());
+}
+
+
+void LGapResolver::AddResultMove(LOperand* from, LOperand* to) {
+  result_.Add(LMoveOperands(from, to));
+}
+
+
+void LGapResolver::ResolveCycle(LGapNode* start, LOperand* marker_operand) {
+  ZoneList<LOperand*> cycle_operands(8);
+  cycle_operands.Add(marker_operand);
+  LGapNode* cur = start;
+  do {
+    cur->MarkResolved();
+    cycle_operands.Add(cur->operand());
+    cur = cur->assigned_from();
+  } while (cur != start);
+  cycle_operands.Add(marker_operand);
+
+  for (int i = cycle_operands.length() - 1; i > 0; --i) {
+    LOperand* from = cycle_operands[i];
+    LOperand* to = cycle_operands[i - 1];
+    AddResultMove(from, to);
+  }
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b, int visited_id) {
+  ASSERT(a != b);
+  LGapNode* cur = a;
+  while (cur != b && cur->visited_id() != visited_id && cur->IsAssigned()) {
+    cur->set_visited_id(visited_id);
+    cur = cur->assigned_from();
+  }
+
+  return cur == b;
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b) {
+  ASSERT(a != b);
+  return CanReach(a, b, next_visited_id_++);
+}
+
+
+void LGapResolver::RegisterMove(LMoveOperands move) {
+  if (move.from()->IsConstantOperand()) {
+    // Constant moves should be last in the machine code. Therefore add them
+    // first to the result set.
+    AddResultMove(move.from(), move.to());
+  } else {
+    LGapNode* from = LookupNode(move.from());
+    LGapNode* to = LookupNode(move.to());
+    if (to->IsAssigned() && to->assigned_from() == from) {
+      move.Eliminate();
+      return;
+    }
+    ASSERT(!to->IsAssigned());
+    if (CanReach(from, to)) {
+      // This introduces a cycle. Save.
+      identified_cycles_.Add(from);
+    }
+    to->set_assigned_from(from);
+  }
+}
+
+
+LGapNode* LGapResolver::LookupNode(LOperand* operand) {
+  for (int i = 0; i < nodes_.length(); ++i) {
+    if (nodes_[i]->operand()->Equals(operand)) return nodes_[i];
+  }
+
+  // No node found => create a new one.
+  LGapNode* result = new LGapNode(operand);
+  nodes_.Add(result);
+  return result;
+}
+
+
 #define __ masm()->
 
 bool LCodeGen::GenerateCode() {

src/ia32/lithium-codegen-ia32.h

@@ -40,8 +40,31 @@ namespace internal {
 
 // Forward declarations.
 class LDeferredCode;
+class LGapNode;
 class SafepointGenerator;
 
+class LGapResolver BASE_EMBEDDED {
+ public:
+  LGapResolver();
+  const ZoneList<LMoveOperands>* Resolve(const ZoneList<LMoveOperands>* moves,
+                                         LOperand* marker_operand);
+
+ private:
+  LGapNode* LookupNode(LOperand* operand);
+  bool CanReach(LGapNode* a, LGapNode* b, int visited_id);
+  bool CanReach(LGapNode* a, LGapNode* b);
+  void RegisterMove(LMoveOperands move);
+  void AddResultMove(LOperand* from, LOperand* to);
+  void AddResultMove(LGapNode* from, LGapNode* to);
+  void ResolveCycle(LGapNode* start, LOperand* marker_operand);
+
+  ZoneList<LGapNode*> nodes_;
+  ZoneList<LGapNode*> identified_cycles_;
+  ZoneList<LMoveOperands> result_;
+  int next_visited_id_;
+};
+
+
 class LCodeGen BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)

src/lithium.cc

@@ -30,158 +30,6 @@
 namespace v8 {
 namespace internal {
 
-
-class LGapNode: public ZoneObject {
- public:
-  explicit LGapNode(LOperand* operand)
-      : operand_(operand), resolved_(false), visited_id_(-1) { }
-
-  LOperand* operand() const { return operand_; }
-  bool IsResolved() const { return !IsAssigned() || resolved_; }
-  void MarkResolved() {
-    ASSERT(!IsResolved());
-    resolved_ = true;
-  }
-  int visited_id() const { return visited_id_; }
-  void set_visited_id(int id) {
-    ASSERT(id > visited_id_);
-    visited_id_ = id;
-  }
-
-  bool IsAssigned() const { return assigned_from_.is_set(); }
-  LGapNode* assigned_from() const { return assigned_from_.get(); }
-  void set_assigned_from(LGapNode* n) { assigned_from_.set(n); }
-
- private:
-  LOperand* operand_;
-  SetOncePointer<LGapNode> assigned_from_;
-  bool resolved_;
-  int visited_id_;
-};
-
-
-LGapResolver::LGapResolver()
-    : nodes_(32),
-      identified_cycles_(4),
-      result_(16),
-      next_visited_id_(0) {
-}
-
-
-const ZoneList<LMoveOperands>* LGapResolver::Resolve(
-    const ZoneList<LMoveOperands>* moves,
-    LOperand* marker_operand) {
-  nodes_.Rewind(0);
-  identified_cycles_.Rewind(0);
-  result_.Rewind(0);
-  next_visited_id_ = 0;
-
-  for (int i = 0; i < moves->length(); ++i) {
-    LMoveOperands move = moves->at(i);
-    if (!move.IsRedundant()) RegisterMove(move);
-  }
-
-  for (int i = 0; i < identified_cycles_.length(); ++i) {
-    ResolveCycle(identified_cycles_[i], marker_operand);
-  }
-
-  int unresolved_nodes;
-  do {
-    unresolved_nodes = 0;
-    for (int j = 0; j < nodes_.length(); j++) {
-      LGapNode* node = nodes_[j];
-      if (!node->IsResolved() && node->assigned_from()->IsResolved()) {
-        AddResultMove(node->assigned_from(), node);
-        node->MarkResolved();
-      }
-      if (!node->IsResolved()) ++unresolved_nodes;
-    }
-  } while (unresolved_nodes > 0);
-  return &result_;
-}
-
-
-void LGapResolver::AddResultMove(LGapNode* from, LGapNode* to) {
-  AddResultMove(from->operand(), to->operand());
-}
-
-
-void LGapResolver::AddResultMove(LOperand* from, LOperand* to) {
-  result_.Add(LMoveOperands(from, to));
-}
-
-
-void LGapResolver::ResolveCycle(LGapNode* start, LOperand* marker_operand) {
-  ZoneList<LOperand*> cycle_operands(8);
-  cycle_operands.Add(marker_operand);
-  LGapNode* cur = start;
-  do {
-    cur->MarkResolved();
-    cycle_operands.Add(cur->operand());
-    cur = cur->assigned_from();
-  } while (cur != start);
-  cycle_operands.Add(marker_operand);
-
-  for (int i = cycle_operands.length() - 1; i > 0; --i) {
-    LOperand* from = cycle_operands[i];
-    LOperand* to = cycle_operands[i - 1];
-    AddResultMove(from, to);
-  }
-}
-
-
-bool LGapResolver::CanReach(LGapNode* a, LGapNode* b, int visited_id) {
-  ASSERT(a != b);
-  LGapNode* cur = a;
-  while (cur != b && cur->visited_id() != visited_id && cur->IsAssigned()) {
-    cur->set_visited_id(visited_id);
-    cur = cur->assigned_from();
-  }
-
-  return cur == b;
-}
-
-
-bool LGapResolver::CanReach(LGapNode* a, LGapNode* b) {
-  ASSERT(a != b);
-  return CanReach(a, b, next_visited_id_++);
-}
-
-
-void LGapResolver::RegisterMove(LMoveOperands move) {
-  if (move.from()->IsConstantOperand()) {
-    // Constant moves should be last in the machine code. Therefore add them
-    // first to the result set.
-    AddResultMove(move.from(), move.to());
-  } else {
-    LGapNode* from = LookupNode(move.from());
-    LGapNode* to = LookupNode(move.to());
-    if (to->IsAssigned() && to->assigned_from() == from) {
-      move.Eliminate();
-      return;
-    }
-    ASSERT(!to->IsAssigned());
-    if (CanReach(from, to)) {
-      // This introduces a cycle. Save.
-      identified_cycles_.Add(from);
-    }
-    to->set_assigned_from(from);
-  }
-}
-
-
-LGapNode* LGapResolver::LookupNode(LOperand* operand) {
-  for (int i = 0; i < nodes_.length(); ++i) {
-    if (nodes_[i]->operand()->Equals(operand)) return nodes_[i];
-  }
-
-  // No node found => create a new one.
-  LGapNode* result = new LGapNode(operand);
-  nodes_.Add(result);
-  return result;
-}
-
-
 bool LParallelMove::IsRedundant() const {
   for (int i = 0; i < move_operands_.length(); ++i) {
     if (!move_operands_[i].IsRedundant()) return false;

src/lithium.h

@@ -36,31 +36,8 @@ namespace v8 {
 namespace internal {
 
 class LCodeGen;
-class LGapNode;
 class Translation;
 
-class LGapResolver BASE_EMBEDDED {
- public:
-  LGapResolver();
-  const ZoneList<LMoveOperands>* Resolve(const ZoneList<LMoveOperands>* moves,
-                                         LOperand* marker_operand);
-
- private:
-  LGapNode* LookupNode(LOperand* operand);
-  bool CanReach(LGapNode* a, LGapNode* b, int visited_id);
-  bool CanReach(LGapNode* a, LGapNode* b);
-  void RegisterMove(LMoveOperands move);
-  void AddResultMove(LOperand* from, LOperand* to);
-  void AddResultMove(LGapNode* from, LGapNode* to);
-  void ResolveCycle(LGapNode* start, LOperand* marker_operand);
-
-  ZoneList<LGapNode*> nodes_;
-  ZoneList<LGapNode*> identified_cycles_;
-  ZoneList<LMoveOperands> result_;
-  int next_visited_id_;
-};
-
-
 class LParallelMove : public ZoneObject {
  public:
   LParallelMove() : move_operands_(4) { }

src/x64/lithium-codegen-x64.cc

@@ -37,6 +37,157 @@ namespace v8 {
 namespace internal {
 
 
+class LGapNode: public ZoneObject {
+ public:
+  explicit LGapNode(LOperand* operand)
+      : operand_(operand), resolved_(false), visited_id_(-1) { }
+
+  LOperand* operand() const { return operand_; }
+  bool IsResolved() const { return !IsAssigned() || resolved_; }
+  void MarkResolved() {
+    ASSERT(!IsResolved());
+    resolved_ = true;
+  }
+  int visited_id() const { return visited_id_; }
+  void set_visited_id(int id) {
+    ASSERT(id > visited_id_);
+    visited_id_ = id;
+  }
+
+  bool IsAssigned() const { return assigned_from_.is_set(); }
+  LGapNode* assigned_from() const { return assigned_from_.get(); }
+  void set_assigned_from(LGapNode* n) { assigned_from_.set(n); }
+
+ private:
+  LOperand* operand_;
+  SetOncePointer<LGapNode> assigned_from_;
+  bool resolved_;
+  int visited_id_;
+};
+
+
+LGapResolver::LGapResolver()
+    : nodes_(32),
+      identified_cycles_(4),
+      result_(16),
+      next_visited_id_(0) {
+}
+
+
+const ZoneList<LMoveOperands>* LGapResolver::Resolve(
+    const ZoneList<LMoveOperands>* moves,
+    LOperand* marker_operand) {
+  nodes_.Rewind(0);
+  identified_cycles_.Rewind(0);
+  result_.Rewind(0);
+  next_visited_id_ = 0;
+
+  for (int i = 0; i < moves->length(); ++i) {
+    LMoveOperands move = moves->at(i);
+    if (!move.IsRedundant()) RegisterMove(move);
+  }
+
+  for (int i = 0; i < identified_cycles_.length(); ++i) {
+    ResolveCycle(identified_cycles_[i], marker_operand);
+  }
+
+  int unresolved_nodes;
+  do {
+    unresolved_nodes = 0;
+    for (int j = 0; j < nodes_.length(); j++) {
+      LGapNode* node = nodes_[j];
+      if (!node->IsResolved() && node->assigned_from()->IsResolved()) {
+        AddResultMove(node->assigned_from(), node);
+        node->MarkResolved();
+      }
+      if (!node->IsResolved()) ++unresolved_nodes;
+    }
+  } while (unresolved_nodes > 0);
+  return &result_;
+}
+
+
+void LGapResolver::AddResultMove(LGapNode* from, LGapNode* to) {
+  AddResultMove(from->operand(), to->operand());
+}
+
+
+void LGapResolver::AddResultMove(LOperand* from, LOperand* to) {
+  result_.Add(LMoveOperands(from, to));
+}
+
+
+void LGapResolver::ResolveCycle(LGapNode* start, LOperand* marker_operand) {
+  ZoneList<LOperand*> cycle_operands(8);
+  cycle_operands.Add(marker_operand);
+  LGapNode* cur = start;
+  do {
+    cur->MarkResolved();
+    cycle_operands.Add(cur->operand());
+    cur = cur->assigned_from();
+  } while (cur != start);
+  cycle_operands.Add(marker_operand);
+
+  for (int i = cycle_operands.length() - 1; i > 0; --i) {
+    LOperand* from = cycle_operands[i];
+    LOperand* to = cycle_operands[i - 1];
+    AddResultMove(from, to);
+  }
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b, int visited_id) {
+  ASSERT(a != b);
+  LGapNode* cur = a;
+  while (cur != b && cur->visited_id() != visited_id && cur->IsAssigned()) {
+    cur->set_visited_id(visited_id);
+    cur = cur->assigned_from();
+  }
+
+  return cur == b;
+}
+
+
+bool LGapResolver::CanReach(LGapNode* a, LGapNode* b) {
+  ASSERT(a != b);
+  return CanReach(a, b, next_visited_id_++);
+}
+
+
+void LGapResolver::RegisterMove(LMoveOperands move) {
+  if (move.from()->IsConstantOperand()) {
+    // Constant moves should be last in the machine code. Therefore add them
+    // first to the result set.
+    AddResultMove(move.from(), move.to());
+  } else {
+    LGapNode* from = LookupNode(move.from());
+    LGapNode* to = LookupNode(move.to());
+    if (to->IsAssigned() && to->assigned_from() == from) {
+      move.Eliminate();
+      return;
+    }
+    ASSERT(!to->IsAssigned());
+    if (CanReach(from, to)) {
+      // This introduces a cycle. Save.
+      identified_cycles_.Add(from);
+    }
+    to->set_assigned_from(from);
+  }
+}
+
+
+LGapNode* LGapResolver::LookupNode(LOperand* operand) {
+  for (int i = 0; i < nodes_.length(); ++i) {
+    if (nodes_[i]->operand()->Equals(operand)) return nodes_[i];
+  }
+
+  // No node found => create a new one.
+  LGapNode* result = new LGapNode(operand);
+  nodes_.Add(result);
+  return result;
+}
+
+
 #define __ masm()->
 
 bool LCodeGen::GenerateCode() {

src/x64/lithium-codegen-x64.h

@@ -40,8 +40,31 @@ namespace internal {
 
 // Forward declarations.
 class LDeferredCode;
+class LGapNode;
 class SafepointGenerator;
 
+class LGapResolver BASE_EMBEDDED {
+ public:
+  LGapResolver();
+  const ZoneList<LMoveOperands>* Resolve(const ZoneList<LMoveOperands>* moves,
+                                         LOperand* marker_operand);
+
+ private:
+  LGapNode* LookupNode(LOperand* operand);
+  bool CanReach(LGapNode* a, LGapNode* b, int visited_id);
+  bool CanReach(LGapNode* a, LGapNode* b);
+  void RegisterMove(LMoveOperands move);
+  void AddResultMove(LOperand* from, LOperand* to);
+  void AddResultMove(LGapNode* from, LGapNode* to);
+  void ResolveCycle(LGapNode* start, LOperand* marker_operand);
+
+  ZoneList<LGapNode*> nodes_;
+  ZoneList<LGapNode*> identified_cycles_;
+  ZoneList<LMoveOperands> result_;
+  int next_visited_id_;
+};
+
+
 class LCodeGen BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)