[turbofan] Reland: Optimize loads from the global object in JSTypeFeedbackSpecializer.

src/compiler/js-type-feedback.h

Index: src/compiler/js-type-feedback.h
diff --git a/src/compiler/js-type-feedback.h b/src/compiler/js-type-feedback.h
index e879b31e3bb6ae16093ef60392cf9f42eb35263a..51faee3a4fc112f511c1a37086f32272473a93f6 100644
--- a/src/compiler/js-type-feedback.h
+++ b/src/compiler/js-type-feedback.h
@@ -17,6 +17,7 @@ namespace internal {
 
 class TypeFeedbackOracle;
 class SmallMapList;
+class CompilationDependencies;
 
 namespace compiler {
 
@@ -50,11 +51,15 @@ class JSTypeFeedbackSpecializer : public Reducer {
  public:
   JSTypeFeedbackSpecializer(JSGraph* jsgraph,
                             JSTypeFeedbackTable* js_type_feedback,
-                            TypeFeedbackOracle* oracle)
+                            TypeFeedbackOracle* oracle,
+                            Handle<GlobalObject> global_object,
+                            CompilationDependencies* dependencies)
       : jsgraph_(jsgraph),
         simplified_(jsgraph->graph()->zone()),
         js_type_feedback_(js_type_feedback),
-        oracle_(oracle) {
+        oracle_(oracle),
+        global_object_(global_object),
+        dependencies_(dependencies) {
     CHECK(js_type_feedback);
   }
 
@@ -62,6 +67,7 @@ class JSTypeFeedbackSpecializer : public Reducer {
 
   // Visible for unit testing.
   Reduction ReduceJSLoadNamed(Node* node);
+  Reduction ReduceJSLoadNamedForGlobalVariable(Node* node);
   Reduction ReduceJSLoadProperty(Node* node);
   Reduction ReduceJSStoreNamed(Node* node);
   Reduction ReduceJSStoreProperty(Node* node);
@@ -71,6 +77,8 @@ class JSTypeFeedbackSpecializer : public Reducer {
   SimplifiedOperatorBuilder simplified_;
   JSTypeFeedbackTable* js_type_feedback_;
   TypeFeedbackOracle* oracle_;
+  Handle<GlobalObject> global_object_;
+  CompilationDependencies* dependencies_;
 
   TypeFeedbackOracle* oracle() { return oracle_; }
   Graph* graph() { return jsgraph_->graph(); }