From: Andrew Cagney <ac131313@redhat.com>
To: Jim Blandy <jimb@redhat.com>
Cc: Mark Kettenis <kettenis@chello.nl>,
mludvig@suse.cz, gdb@sources.redhat.com,
Alexandre Oliva <aoliva@redhat.com>
Subject: Re: dwarf-frame.c question
Date: Fri, 30 May 2003 20:32:00 -0000 [thread overview]
Message-ID: <3ED7BFD1.7060902@redhat.com> (raw)
In-Reply-To: <vt2ptm09nz9.fsf@zenia.red-bean.com>
> Andrew Cagney <ac131313@redhat.com> writes:
>
>> One idea (the origins of which are unknown) is for the compiler to
>> generate CFI info containing no addresses and have GDB look for that
>> dependant on the PC address being obtained using return or resume
>> (sigtramp, sentinel).
>
>
> I don't understand this. Could you explain the idea in more detail?
A similar technique to the line number information where there are two
line number entries for the start of function so that GDB can find the
end of the function prologue given:
int foo (int i) { int j = i * i; return j; }
In this case there would be two CFI entries covering the code at "1:"
(assuming its possible):
> foo ()
> {
> if (i)
> abort (with, lots, of parameters)
> do; normal; stuff;
> }
>
> it can be turned into:
>
> branch !i, 1:
> push with
> push lots
> push of
> push parameters
> call abort
> 1:
> do
> normal
> stuff
- [1:, 1:): describing the lost return instruction
- [1:, end-of-function) describing the real code
GDB could pick 'n' choose.
The other thing to do is to test this on an alternative compiler that
generates CFI.
Andrew
next prev parent reply other threads:[~2003-05-30 20:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-27 15:19 Michal Ludvig
2003-05-29 15:44 ` Mark Kettenis
2003-05-29 19:54 ` Andrew Cagney
2003-05-29 22:22 ` Mark Kettenis
2003-05-29 22:43 ` Michal Ludvig
2003-05-29 23:13 ` Andrew Cagney
2003-05-30 1:34 ` Daniel Jacobowitz
2003-05-30 20:21 ` Jim Blandy
2003-05-30 20:21 ` Jim Blandy
2003-05-30 20:32 ` Andrew Cagney [this message]
2003-06-03 0:04 ` Jim Blandy
2003-06-03 5:47 ` Richard Henderson
2003-06-03 6:32 ` Jim Blandy
2003-06-03 15:58 ` Richard Henderson
2003-06-03 17:38 ` Richard Henderson
2003-06-03 20:12 ` Alexandre Oliva
2003-05-30 20:44 ` Alexandre Oliva
2003-06-01 5:59 Richard Henderson
2003-06-01 10:00 ` Mark Kettenis
2003-06-02 20:34 ` Richard Henderson
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=3ED7BFD1.7060902@redhat.com \
--to=ac131313@redhat.com \
--cc=aoliva@redhat.com \
--cc=gdb@sources.redhat.com \
--cc=jimb@redhat.com \
--cc=kettenis@chello.nl \
--cc=mludvig@suse.cz \
/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).