A collection of context-related refactoring changes.

src/contexts.cc

Index: src/contexts.cc
diff --git a/src/contexts.cc b/src/contexts.cc
index f6031f1d058cc5c135b6d077b45162d37bab3ef0..c9c944c925c2250fa45599b19813936955573320 100644
--- a/src/contexts.cc
+++ b/src/contexts.cc
@@ -96,7 +96,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
       PrintF("\n");
     }
 
-    // check extension/with object
+    // Check extension/with/global object.
     if (context->has_extension()) {
       Handle<JSObject> extension = Handle<JSObject>(context->extension(),
                                                     isolate);
@@ -119,7 +119,7 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
       }
     }
 
-    if (context->is_function_context()) {

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

Global contexts used to satisfy this predicate, but they have the empty function
as closure, so there were never any locals, parameters, or a function name. 
It's safe to skip this for global contexts.

[Mads Ager (chromium), 2011/06/09 07:31:00]

Could you add a comment to that effect before the conditional?

+    if (context->IsFunctionContext()) {
       // we have context-local slots
 
       // check non-parameter locals in context
@@ -189,9 +189,8 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
     // proceed with enclosing context
     if (context->IsGlobalContext()) {
       follow_context_chain = false;
-    } else if (context->is_function_context()) {

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

Global contexts couldn't reach this site.

-      context = Handle<Context>(Context::cast(context->closure()->context()),
-                                isolate);
+    } else if (context->IsFunctionContext()) {
+      context = Handle<Context>(context->closure()->context(), isolate);
     } else {
       context = Handle<Context>(context->previous(), isolate);
     }
@@ -212,11 +211,12 @@ bool Context::GlobalIfNotShadowedByEval(Handle<String> name) {
   // before the global context and check that there are no context
   // extension objects (conservative check for with statements).
   while (!context->IsGlobalContext()) {
-    // Check if the context is a potentially a with context.
+    // Check if the context is a catch or with context, or has called
+    // non-strict eval.
     if (context->has_extension()) return false;
 
     // Not a with context so it must be a function context.
-    ASSERT(context->is_function_context());

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

Global contexts couldn't reach this site.

+    ASSERT(context->IsFunctionContext());
 
     // Check non-parameter locals.
     Handle<SerializedScopeInfo> scope_info(