Towards removing dependency from generic lowering on compilation info.

src/compiler/js-context-specialization.h

 // Copyright 2014 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_JS_CONTEXT_SPECIALIZATION_H_
 #define V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_
 
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/js-graph.h"
 #include "src/contexts.h"
 #include "src/v8.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // Specializes a given JSGraph to a given context, potentially constant folding
 // some {LoadContext} nodes or strength reducing some {StoreContext} nodes.
 class JSContextSpecializer {

[titzer, 2014/08/20 12:54:38]

This class is becoming more general now. I think we should rename this to
JSContextAccessBuilder or something similar.

  public:
   JSContextSpecializer(CompilationInfo* info, JSGraph* jsgraph, Node* context)
-      : info_(info), jsgraph_(jsgraph), context_(context) {}
+      : specialized_(false),

[titzer, 2014/08/20 12:54:38]

If you make this a parameter, then you can simplify the pipeline a bit. It can
just always call SpecializeToContext(), which will be a no-op if the specializer
is not figured to do specialization.

+        info_(info),
+        jsgraph_(jsgraph),
+        context_(context) {}
 
   void SpecializeToContext();
   Reduction ReduceJSLoadContext(Node* node);
   Reduction ReduceJSStoreContext(Node* node);
+  Node* InsertBuiltinLoadBefore(Node* before, Builtins::JavaScript id);
 
  private:
+  bool specialized_;
   CompilationInfo* info_;
   JSGraph* jsgraph_;
   Node* context_;
 };
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_