From: Tom Tromey <tom@tromey.com>
To: Mike Tsai via Gdb <gdb@sourceware.org>
Cc: Mike Tsai <bibibobibo@gmail.com>
Subject: Re: set sysroot and debug-file-directory don't work together?
Date: Sun, 10 Dec 2023 16:11:23 -0700 [thread overview]
Message-ID: <87zfyh64bo.fsf@tromey.com> (raw)
In-Reply-To: <CAEopbebOSwvmLEkzGxj7mmQgBSnk11wDVNBQeCZ8XDsaptnyMw@mail.gmail.com> (Mike Tsai via Gdb's message of "Mon, 27 Nov 2023 12:55:19 -0800")
>>>>> "Mike" == Mike Tsai via Gdb <gdb@sourceware.org> writes:
Mike> I have a dummy question regarding using "set sysroot LOCAL_DIR" and
Mike> "set debug-file-directory SOME_OTHER_DIR" together to find symbols for
Mike> a debug session. I was under the impression, gdb is able to fallback
Mike> to debug-file-directory and do build-id style lookup if symbols cannot
Mike> be found in "sysroot", but it does not seem to be doing that so I am
Mike> curious if it's I am doing something wrong or this is not "supported".
I didn't know the answer either, so I looked through the source a bit.
In the end it's just a pain to try to figure out what this code is
doing. Far easier, probably, is for you to:
set debug separate-debug-file 1
... and then try. I think that will show exactly the paths gdb is
trying to use.
I tried it with "file /bin/ls":
(gdb) file /bin/ls
Reading symbols from /bin/ls...
Looking for separate debug info (build-id) for /usr/bin/ls
Trying /usr/lib/debug/.build-id/a1/46002a40b622e4d8420c5b96513f0784c8eb7b.debug... no, unable to compute real path
Trying target:/usr/lib/debug/.build-id/a1/46002a40b622e4d8420c5b96513f0784c8eb7b.debug... no, unable to open.
Looking for separate debug info (debug link) for /usr/bin/ls
Trying /usr/bin/ls-9.1-12.fc38.x86_64.debug... no, unable to open.
Trying /usr/bin/.debug/ls-9.1-12.fc38.x86_64.debug... no, unable to open.
Trying /usr/lib/debug//usr/bin/ls-9.1-12.fc38.x86_64.debug... no, unable to open.
Reading symbols from .gnu_debugdata for /usr/bin/ls...
(No debugging symbols found in .gnu_debugdata for /usr/bin/ls)
... IMO pretty readable.
If I "set sysroot /tmp/nonesuch" first, then only that "target:" line
changes.
This order seems sort of backward to me somehow, like if I had a
complete sysroot setup (including all separate debug files), then "set
sysroot" should be sufficient and it should never check outside. I
suppose with .build-id the idea is that the hashes are global and so it
doesn't matter exactly where gdb finds the match.
Tom
prev parent reply other threads:[~2023-12-10 23:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-27 20:55 Mike Tsai
2023-12-10 23:11 ` Tom Tromey [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87zfyh64bo.fsf@tromey.com \
--to=tom@tromey.com \
--cc=bibibobibo@gmail.com \
--cc=gdb@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).