[stubs] Use a single slot for context globals.

src/scopeinfo.cc

Index: src/scopeinfo.cc
diff --git a/src/scopeinfo.cc b/src/scopeinfo.cc
index c79a98060cccb039999c811e0e5ac626bb10a2e4..fda3b1bd38978c68a3618981ed4728393958e2a1 100644
--- a/src/scopeinfo.cc
+++ b/src/scopeinfo.cc
@@ -340,7 +340,7 @@ int ScopeInfo::ContextLength() {
                        scope_type() == MODULE_SCOPE;
 
     if (has_context) {
-      return Context::MIN_CONTEXT_SLOTS + context_locals + 2 * context_globals +
+      return Context::MIN_CONTEXT_SLOTS + context_locals + context_globals +
              (function_name_context_slot ? 1 : 0);
     }
   }
@@ -553,7 +553,7 @@ int ScopeInfo::ContextSlotIndex(Handle<ScopeInfo> scope_info,
           var -= scope_info->ContextLocalCount();
           *location = VariableLocation::GLOBAL;
           result = Context::MIN_CONTEXT_SLOTS +
-                   scope_info->ContextLocalCount() + 2 * var;
+                   scope_info->ContextLocalCount() + var;
         }
 
         context_slot_cache->Update(scope_info, name, *mode, *location,
@@ -573,15 +573,10 @@ int ScopeInfo::ContextSlotIndex(Handle<ScopeInfo> scope_info,
 
 
 String* ScopeInfo::ContextSlotName(int slot_index) {
-  // TODO(bmeurer): Simplify this once we have only a single slot for both reads
-  // and writes to context globals;  currently we have 2 slots per context
-  // global, and these are located after the common context slots (of which we
-  // always have Context::MIN_CONTEXT_SLOTS) and the context locals.
-  int const var =
-      slot_index - (Context::MIN_CONTEXT_SLOTS + ContextLocalCount());
+  int const var = slot_index - Context::MIN_CONTEXT_SLOTS;
   DCHECK_LE(0, var);
-  DCHECK_LT(var, 2 * ContextGlobalCount());
-  return ContextLocalName(ContextLocalCount() + var / 2);
+  DCHECK_LT(var, ContextLocalCount() + ContextGlobalCount());
+  return ContextLocalName(var);
 }