From: Andrew Burgess <aburgess@redhat.com>
To: Luis Machado <luis.machado@arm.com>, hilbert <swdtian@163.com>,
gdb@sourceware.org
Subject: Re: How does GDB get the function call stack
Date: Thu, 18 Aug 2022 15:05:16 +0100 [thread overview]
Message-ID: <87r11dabqb.fsf@redhat.com> (raw)
In-Reply-To: <217b746f-65e8-66c0-1678-376eb8cb1aca@arm.com>
Luis Machado via Gdb <gdb@sourceware.org> writes:
> On 8/16/22 08:43, hilbert via Gdb wrote:
>> Hi ,
>> There are 4 ways to get the function call stack in the GDB Internals Manual. https://sourceware.org/gdb/papers/unwind.html
>> For x86_64, does GDB get information by parsing the .eh_frame section? Or just get the call stack by Parse the function prologues.
>>
>>
>>
>
> I'd say mostly 1 and 2. 1 is usually used with functions without debug
> information. 2 is used when there is debug information.
To expand on this a little, at least for version of GCC I'm using on
x86-64, the .eh_frame data replaces the .debug_frame data, so #2 and #3
are effectively merged.
The two "issues" raised against .eh_frame don't make sense to me. As
I understand it the .eh_frame encoding is roughly the same as the
.debug_frame encoding, so I don't think there's much space saving, and
GDB reads the .eh_frame information from the ELF, so the read-only
concern seems like a non-issue.
Thanks,
Andrew
next prev parent reply other threads:[~2022-08-18 14:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-16 7:43 hilbert
2022-08-16 7:56 ` Luis Machado
2022-08-16 9:19 ` hilbert
2022-08-16 9:33 ` Andrew Dinn
2022-08-16 10:16 ` hilbert
2022-08-16 12:48 ` Andrew Dinn
2022-08-16 13:18 ` hilbert
2022-08-16 13:27 ` Luis Machado
2022-08-16 13:46 ` hilbert
2022-08-18 14:05 ` Andrew Burgess [this message]
2022-08-19 1:57 ` hilbert
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