A collection of context-related refactoring changes.

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index a89e26228150502475e29d96e017929ea61bfd4c..64bfc4cd4f938d0c572f9ead9ad6e9263ba78570 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -289,8 +289,17 @@ class Context: public FixedArray {
   // Compute the global context by traversing the context chain.
   Context* global_context();
 
-  // Tells if this is a function context (as opposed to a 'with' context).
-  bool is_function_context() { return unchecked_previous() == NULL; }

[Kevin Millikin (Chromium), 2011/06/08 16:35:52]

I plan on next using previous() for context iteration, but then function
contexts will have to have previous() != NULL.

+  // Predicates for context types.  IsGlobalContext is defined on Object
+  // because we frequently have to know if arbitrary objects are global
+  // contexts.
+  bool IsFunctionContext() {
+    Map* map = this->map();
+    return map == map->GetHeap()->function_context_map();
+  }
+  bool IsCatchContext() {
+    Map* map = this->map();
+    return map == map->GetHeap()->catch_context_map();
+  }
 
   // Tells whether the global context is marked with out of memory.
   inline bool has_out_of_memory();