Refactor Hydrogen GVN into an HPhase and use the phase zone.

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index fdd2f75779d97111a3134f6db8681e565e0a24c5..84dbae1b6f8f88ce4795d8869612df651ef9bb15 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -284,7 +284,6 @@ class HGraph: public ZoneObject {
   void MarkDeoptimizeOnUndefined();
   void ComputeMinusZeroChecks();
   void ComputeSafeUint32Operations();
-  void GlobalValueNumbering();
   bool ProcessArgumentsObject();
   void EliminateRedundantPhis();
   void Canonicalize();
@@ -428,6 +427,8 @@ class HGraph: public ZoneObject {
   HConstant* GetConstant(SetOncePointer<HConstant>* pointer,
                          int32_t integer_value);
 
+  template<typename Phase>
+  void Run() { Phase phase(this, info()->phase_zone()); phase.Run(); }

[danno, 2013/06/25 15:20:54]

Isn't this from another CL?

[Benedikt Meurer, 2013/06/27 08:20:04]

Done.

   void MarkLive(HValue* ref, HValue* instr, ZoneList<HValue*>* worklist);
   void MarkLiveInstructions();
   void RemoveDeadInstructions();
@@ -1957,13 +1958,20 @@ class HStatistics: public Malloced {
 
 class HPhase : public CompilationPhase {
  public:
+  // TODO(bmeurer) Remove this constructor once all
+  // Hydrogen phases have been migrated
   HPhase(const char* name, HGraph* graph)
       : CompilationPhase(name, graph->isolate(), graph->zone()),
         graph_(graph) { }
+  HPhase(const char* name, HGraph* graph, Zone* zone);

[danno, 2013/06/25 15:20:54]

again, why do you need to pass the zone in? Either you need the graph zone (with
graph->zone()) or the phase zone (graph->info()->phase_zone()). Either way, you
shouldn't have to pass it in explicitly.

[Benedikt Meurer, 2013/06/27 08:20:04]

Done.

   ~HPhase();
 
+ protected:
+  HGraph* graph() const { return graph_; }
+
  private:
   HGraph* graph_;
+  unsigned graph_zone_start_allocation_size_;
 
   DISALLOW_COPY_AND_ASSIGN(HPhase);
 };