Reapply "Add a level of indirection to exception handler addresses."

Reapply "Add a level of indirection to exception handler addresses."

Original commit message:

Add a level of indirection to exception handler addresses.

To support deoptimization of exception handlers, the handler address in the
stack is converted to a pair of code object and an index into a separate
table of code offsets.  The index part is invariant under deoptimization.
The index is packed into the handler state field so that handler size does
not change.

R=vegorov@chromium.org
BUG=
TEST=

Committed: http://code.google.com/p/v8/source/detail?r=9977

[Kevin Millikin (Chromium), 2011-11-11 13:44:52]

The diff is this, in objects-visiting-inl.h (and there is an analogous comment
in the templated CodeIterateBody):

--- a/src/objects-visiting-inl.h
+++ b/src/objects-visiting-inl.h
@@ -104,7 +104,10 @@ void Code::CodeIterateBody(ObjectVisitor* v) {
                   RelocInfo::ModeMask(RelocInfo::DEBUG_BREAK_SLOT) |
                   RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
 
+  // There are two places where we iterate code bodies: here and the
+  // templated CodeIterateBody (below).  They should be kept in sync.
   IteratePointer(v, kRelocationInfoOffset);
+  IteratePointer(v, kHandlerTableOffset);
   IteratePointer(v, kDeoptimizationDataOffset);

[Vyacheslav Egorov (Chromium), 2011-11-11 13:46:09]

LGTM.

sorry for missing it the first time.