Preserve error message during finally block in try..finally.

Preserve error message during finally block in try..finally.

R=ulan@chromium.org
BUG=129171
TEST=test-api/TryFinallyMessage

Committed: https://code.google.com/p/v8/source/detail?r=11753

[Yang, 2012-06-08 14:37:10]

PTAL.

In try..finally, if an exception is thrown in the try block, execute the finally
block before (re)throwing the exception.  It can happen that the finally block
triggers IC initialization, which calls to Execution::Call (with
uncaught-exception handling and everything).  Any exception and the
corresponding message is then cleared before we return to the finally block from
initializing the IC.  The exception itself is restored, but the error message is
now lost.

This CL add tracking of nesting levels of finally blocks (called by throwing an
exception) and prevents clearing the message inside nested blocks.

[Yang, 2012-06-08 15:39:01]

On 2012/06/08 14:37:10, Yang wrote:
> PTAL.
> 
> In try..finally, if an exception is thrown in the try block, execute the
finally
> block before (re)throwing the exception.  It can happen that the finally block
> triggers IC initialization, which calls to Execution::Call (with
> uncaught-exception handling and everything).  Any exception and the
> corresponding message is then cleared before we return to the finally block
from
> initializing the IC.  The exception itself is restored, but the error message
is
> now lost.
> 
> This CL add tracking of nesting levels of finally blocks (called by throwing
an
> exception) and prevents clearing the message inside nested blocks.

Please take another look.

[ulan, 2012-06-11 09:45:57]

LGTM