From: Mark Wielaard <mark@klomp.org>
To: Sasha Da Rocha Pinheiro <darochapinhe@wisc.edu>,
"elfutils-devel@sourceware.org" <elfutils-devel@sourceware.org>
Subject: Re: dwarf_begin_elf() won't create handle without .debug_* sections
Date: Fri, 01 Jun 2018 11:10:00 -0000 [thread overview]
Message-ID: <1527851437.12946.35.camel@klomp.org> (raw)
In-Reply-To: <BN6PR06MB293237A6F4E88363011B1EF4A66C0@BN6PR06MB2932.namprd06.prod.outlook.com>
On Wed, 2018-05-30 at 17:32 +0000, Sasha Da Rocha Pinheiro wrote:
> I just fixed something interesting in Dyninst. We were assuming that
> the FDEs were following the CIE in the eh_frame section, but this is
> not correct. I found them mixed in an ARM binary and this caused
> wrong parsing.
> So we I did dwarf_next_cfi() in the loop to go through the FDE's, and
> I had to use it again in the loop to get the corresponding CIE. I
> don't think it's a problem, just kinda not intuitive, for who wants
> to understand after me.
dwarf_next_cfi () is a very low level interface. Other cfi related
interfaces that work with a Dwarf_CFI handle (dwarf_getcfi () and
dwarf_getcfi_elf ()) and don't make any assumptions about the order.
But they do build up a cache of all entries. In return for some extra
memory usage you can use them without caring about the order in which
they appear with dwarf_cfi_addrframe () by just giving an address you
are interested in and using dwarf_frame_info (), dwarf_frame_cfa () and
dwarf_frame_register () to extract the information (which might be
less/different than what you would get from the "raw" Dwarf_CFI_Entry).
Cheers,
Mark
prev parent reply other threads:[~2018-06-01 11:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-23 20:09 Sasha Da Rocha Pinheiro
2018-05-24 16:28 ` Mark Wielaard
2018-05-30 17:32 ` Sasha Da Rocha Pinheiro
2018-06-01 11:10 ` Mark Wielaard [this message]
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