On 12/11/2017 03:32 PM, Paolo Bonzini wrote: > On 11/12/2017 15:11, Eric Blake wrote: >> I don't know if there is a way to make gcc insert stack-unwind >> directives that are honored across longjmp (I know C++ does it for >> exceptions; so there may be a way, and I just don't know it). > > Probably -fexceptions. >
Well, that's what 'info gcc' mentions:
'cleanup (CLEANUP_FUNCTION)'
The 'cleanup' attribute runs a function when the variable goes out
of scope. This attribute can only be applied to auto function
scope variables; it may not be applied to parameters or variables
with static storage duration. The function must take one
parameter, a pointer to a type compatible with the variable. The
return value of the function (if any) is ignored.
If '-fexceptions' is enabled, then CLEANUP_FUNCTION is run during
the stack unwinding that happens during the processing of the
exception. Note that the 'cleanup' attribute does not allow the
exception to be caught, only to perform an action. It is undefined
what happens if CLEANUP_FUNCTION does not return normally.
but adding -fexceptions to my sample program does NOT make a difference
(apparently, unwind cleanup triggered by C++ exceptions is NOT the same
as unwinding done by longjmp()).
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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