[turbofan] Improve caching in escape analysis.

src/compiler/escape-analysis.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_ESCAPE_ANALYSIS_H_
 #define V8_COMPILER_ESCAPE_ANALYSIS_H_
 
 #include "src/base/flags.h"
 #include "src/compiler/graph.h"
 
@@ skipping 58 matching lines @@
   ZoneVector<EscapeStatusFlags> info_;
   ZoneDeque<Node*> queue_;
 
   DISALLOW_COPY_AND_ASSIGN(EscapeStatusAnalysis);
 };
 
 
 DEFINE_OPERATORS_FOR_FLAGS(EscapeStatusAnalysis::EscapeStatusFlags)
 
 
-class MergeCache {
- public:
-  explicit MergeCache(Zone* zone)
-      : states_(zone), objects_(zone), fields_(zone) {
-    states_.reserve(4);
-    objects_.reserve(4);
-    fields_.reserve(4);
-  }
-  ZoneVector<VirtualState*>& states() { return states_; }
-  ZoneVector<VirtualObject*>& objects() { return objects_; }
-  ZoneVector<Node*>& fields() { return fields_; }
-  void Clear() {
-    states_.clear();
-    objects_.clear();
-    fields_.clear();
-  }
-
- private:
-  ZoneVector<VirtualState*> states_;
-  ZoneVector<VirtualObject*> objects_;
-  ZoneVector<Node*> fields_;
-};
+// Forward Declaration.
+class MergeCache;
 
 
 // EscapeObjectAnalysis simulates stores to determine values of loads if
 // an object is virtual and eliminated.
 class EscapeAnalysis {
  public:
   EscapeAnalysis(Graph* graph, CommonOperatorBuilder* common, Zone* zone);
   ~EscapeAnalysis();
 
   void Run();
@@ skipping 43 matching lines @@
   Graph* graph() const { return graph_; }
   CommonOperatorBuilder* common() const { return common_; }
   Zone* zone() const { return zone_; }
 
   Graph* const graph_;
   CommonOperatorBuilder* const common_;
   Zone* const zone_;
   ZoneVector<VirtualState*> virtual_states_;
   ZoneVector<Node*> replacements_;
   EscapeStatusAnalysis escape_status_;
-  MergeCache cache_;
+  MergeCache* cache_;
 
   DISALLOW_COPY_AND_ASSIGN(EscapeAnalysis);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_ESCAPE_ANALYSIS_H_