A start on allowing non-local control flow, for exceptions, try-finally, and ...

src/fast-codegen.h

Index: src/fast-codegen.h
===================================================================
--- src/fast-codegen.h	(revision 3310)
+++ src/fast-codegen.h	(working copy)
@@ -43,6 +43,8 @@
         function_(NULL),
         script_(script),
         is_eval_(is_eval),
+        function_return_(),
+        return_label_(NULL),
         loop_depth_(0),
         true_label_(NULL),
         false_label_(NULL) {
@@ -117,7 +119,14 @@
   FunctionLiteral* function_;
   Handle<Script> script_;
   bool is_eval_;
-  Label return_label_;
+  Label function_return_;// Label of the actual return sequence.
+  Label* return_label_;  // Label to jump to from a return statement.
+  // If there are finally blocks from try..finally that must be executed,
+  // this is the entry point of a finally block, shadowing the real return.
+  int return_stack_height_;  // The height of the stack at return_label_.
+  int scope_stack_height_;  // The number of elements above the frame pointer
+  // that are on the stack due to enclosing scopes.  Does not include the
+  // expression stack, but does include elements pushed by with and for..in.
   int loop_depth_;
 
   Label* true_label_;