This patch addresses the bug detailed in gnats pr 2495 and after the 
conversion to bugzilla: pr 9600

Due to the method that GDB uses to construct a frame for an inferior 
function call, the unwinder can terminate the inferior if it raises an 
exception and relies on an out-of-frame handler to normally handle that 
exception. For most systems GCC uses the exception handling strategy 
documented here:  http://www.codesourcery.com/public/cxx-abi/ . If the 
function that raises the exception relies on an out-of-frame handler, 
the single dummy frame constructed by GDB for the inferior function call 
does not allow the unwinder to walk the stack looking for an appropriate 
handler. Briefly, if this happens the unwinder terminates the inferior 
via a call to the default exception handler on the (wrong) assumption 
that there is no user-created handler for the exception.

This patch addresses that by gating access to std::terminate in an 
inferior function call. If it enters that function, it is popped back to 
the calling state and "rescues" the inferior. This patch also adds the 
functionality to turn this gating behaviour on or off. The default is on.

This patch applies cleanly to CVS GDB head. Tested on x8664 with no 
regressions.

Regards

Phil
   
    gdb/ChangeLog
    2009-04-23  Phil Muldoon  <pmuldoon@redhat.com>
   
        * infcall.c (show_unwind_on_terminating_exception_p): New
        function.
        (call_function_by_hand): Create breakpoint and clean-up call for
        std::terminate.breakpoint. Add unwind_on_terminating_exception_p
        gate. Pop frame on breakpoint hit.
        (_initialize_infcall): Add add_setshow_boolean_cmd for
        unwind-on-terminating-exception.
   
    gdb/testsuite/ChangeLog
    2009-04-23  Phil Muldoon  <pmuldoon@redhat.com>
   
        * gdb.cp/gdb2495.cc: New file.
        * gdb.cp/gdb2495.exp: New file.
   
    gdb/doc/ChangeLog
    2009-04-23  Phil Muldoon  <pmuldoon@redhat.com>
   
        * doc/gdb.texinfo (Calling): Document
        set-unwind-on-terminating-exception usage.