Merge arguments branch to bleeding merge.

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index 100e1a256e689167dc2176f90935c5e2eb90ca17..6a45baf0e18c69ae9cd97ff412691f4e82a9053a 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -88,6 +88,8 @@ enum ContextLookupFlags {
   V(JS_ARRAY_MAP_INDEX, Map, js_array_map)\
   V(REGEXP_RESULT_MAP_INDEX, Map, regexp_result_map)\
   V(ARGUMENTS_BOILERPLATE_INDEX, JSObject, arguments_boilerplate) \
+  V(ALIASED_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \
+    aliased_arguments_boilerplate) \
   V(STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX, JSObject, \
     strict_mode_arguments_boilerplate) \
   V(MESSAGE_LISTENERS_INDEX, JSObject, message_listeners) \
@@ -181,20 +183,15 @@ class Context: public FixedArray {
     CLOSURE_INDEX,
     FCONTEXT_INDEX,
     PREVIOUS_INDEX,
-    // The extension slot is used for either the global object (in global
-    // contexts), eval extension object (function contexts), subject of with
-    // (with contexts), or the variable name (catch contexts).
     EXTENSION_INDEX,
     GLOBAL_INDEX,
     MIN_CONTEXT_SLOTS,
 
-    // This slot holds the thrown value in catch contexts.
-    THROWN_OBJECT_INDEX = MIN_CONTEXT_SLOTS,
-
     // These slots are only in global contexts.
     GLOBAL_PROXY_INDEX = MIN_CONTEXT_SLOTS,
     SECURITY_TOKEN_INDEX,
     ARGUMENTS_BOILERPLATE_INDEX,
+    ALIASED_ARGUMENTS_BOILERPLATE_INDEX,
     STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX,
     JS_ARRAY_MAP_INDEX,
     REGEXP_RESULT_MAP_INDEX,
@@ -271,9 +268,9 @@ class Context: public FixedArray {
   }
   void set_previous(Context* context) { set(PREVIOUS_INDEX, context); }
 
-  bool has_extension() { return extension() != NULL; }
-  Object* extension() { return get(EXTENSION_INDEX); }
-  void set_extension(Object* object) { set(EXTENSION_INDEX, object); }
+  bool has_extension() { return unchecked_extension() != NULL; }
+  JSObject* extension() { return JSObject::cast(unchecked_extension()); }
+  void set_extension(JSObject* object) { set(EXTENSION_INDEX, object); }
 
   GlobalObject* global() {
     Object* result = get(GLOBAL_INDEX);
@@ -303,10 +300,6 @@ class Context: public FixedArray {
     Map* map = this->map();
     return map == map->GetHeap()->catch_context_map();
   }
-  bool IsWithContext() {
-    Map* map = this->map();
-    return map == map->GetHeap()->with_context_map();
-  }
 
   // Tells whether the global context is marked with out of memory.
   inline bool has_out_of_memory();
@@ -395,6 +388,7 @@ class Context: public FixedArray {
  private:
   // Unchecked access to the slots.
   Object* unchecked_previous() { return get(PREVIOUS_INDEX); }
+  Object* unchecked_extension() { return get(EXTENSION_INDEX); }
 
 #ifdef DEBUG
   // Bootstrapping-aware type checks.