Keep a canonical list of shared function infos.

src/runtime/runtime-function.cc

Index: src/runtime/runtime-function.cc
diff --git a/src/runtime/runtime-function.cc b/src/runtime/runtime-function.cc
index 6283f1ee800c8cd2cbda1e6907ca92e2facb96b2..281a0ebd7d67c006ef90ba1397a26e8fe94ff4f2 100644
--- a/src/runtime/runtime-function.cc
+++ b/src/runtime/runtime-function.cc
@@ -232,7 +232,8 @@ RUNTIME_FUNCTION(Runtime_SetCode) {
   target_shared->set_feedback_vector(source_shared->feedback_vector());
   target_shared->set_internal_formal_parameter_count(
       source_shared->internal_formal_parameter_count());
-  target_shared->set_script(source_shared->script());
+  SharedFunctionInfo::SetScript(

[Michael Starzinger, 2015/06/19 11:17:08]

As discussed offline: It might make sense to visually separate this handlified
call from the pure assignment by just moving it out of the block to around line
246 for example. Applies here and to some other call-site as well.

Also: An interesting experiment might be to insert an explicit GC call into
SetScript and see if that flushes out any bugs with SharedFunctionInfo objects
being in an inconsistent state.

+      target_shared, Handle<Object>(source_shared->script(), isolate));
   target_shared->set_start_position_and_type(
       source_shared->start_position_and_type());
   target_shared->set_end_position(source_shared->end_position());