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From: Florian Weimer <fweimer@redhat.com>
To: Andreas Krebbel via Gcc <gcc@gcc.gnu.org>
Subject: Re: CFI for saved argument registers
Date: Mon, 16 May 2022 15:25:52 +0200	[thread overview]
Message-ID: <87lev1sj6n.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <7d266787-9a64-07e6-bf7b-1bd01119517c@linux.ibm.com> (Andreas Krebbel via Gcc's message of "Mon, 16 May 2022 08:29:32 +0200")

* Andreas Krebbel via Gcc:

> For that purpose I save the argument registers to the stack as we
> would do for a variable argument lists. But this time I also provide
> the CFI to allow the unwinder to locate the save slots.  Since I never
> actually intend to restore the content there is no matching
> cfi_restore for the cfi_offset and dwarf2cfi complains about the
> traces being inconsistent because of that. I couldn't find a way to
> prevent this.
>
> The only way I see right now is adding a new reg note to invalidate
> the save information in the reg_save array in dwarf2cfi.
>
> Would this be acceptable? Is there perhaps an easier way to achieve that?

This is very interesting.  I think we should do this in glibc for abort
and __assert_fail for as many registers as possible, hopefully
preserving more information for debuggers.

Thanks,
Florian


  reply	other threads:[~2022-05-16 13:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-16  6:29 Andreas Krebbel
2022-05-16 13:25 ` Florian Weimer [this message]
2022-05-16 14:39 ` Andreas Schwab
2022-05-17  6:19   ` Andreas Krebbel
2022-05-31 12:11 ` Andreas Krebbel

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