Force context allocation for variables in generator scopes.

src/scopes.h

Index: src/scopes.h
diff --git a/src/scopes.h b/src/scopes.h
index 3ca2dcf0ce259c6fafc57bb05a3e4bbf2160671e..cd53820b8df0684e83368d5f9dd7ca86f5048333 100644
--- a/src/scopes.h
+++ b/src/scopes.h
@@ -269,6 +269,17 @@ class Scope: public ZoneObject {
     end_position_ = statement_pos;
   }
 
+  // In some cases we want to force context allocation for a whole scope.  For
+  // example in generators, allocating variables in contexts minimizes the work

[Michael Starzinger, 2013/04/05 11:38:42]

Can we move the second sentence of this comment to parser.cc where the context
allocation for generators is forced? Also I would rephrase it to "For now
generators ..." because we might want to change that in the (distant) future
when we add Crankshaft support for generators.

[wingo, 2013/04/05 12:25:06]

Done.

+  // to suspend and resume.
+  void ForceContextAllocation() {
+    ASSERT(!already_resolved());
+    force_context_allocation_ = true;
+  }
+  bool has_forced_context_allocation() const {
+    return force_context_allocation_;
+  }
+
   // ---------------------------------------------------------------------------
   // Predicates.
 
@@ -494,6 +505,7 @@ class Scope: public ZoneObject {
   bool outer_scope_calls_non_strict_eval_;
   bool inner_scope_calls_eval_;
   bool force_eager_compilation_;
+  bool force_context_allocation_;
 
   // True if it doesn't need scope resolution (e.g., if the scope was
   // constructed based on a serialized scope info or a catch context).