From: Pedro Alves <palves@redhat.com>
To: Tristan Gingold <gingold@adacore.com>
Cc: Jack Howarth <howarth@bromo.med.uc.edu>, gdb@sourceware.org
Subject: Re: PR13901
Date: Mon, 02 Apr 2012 14:17:00 -0000 [thread overview]
Message-ID: <4F79B4CB.4090903@redhat.com> (raw)
In-Reply-To: <54AC9EED-A577-41CA-B09D-3ED879877D0C@adacore.com>
On 04/02/2012 03:06 PM, Tristan Gingold wrote:
>
> On Apr 2, 2012, at 3:56 PM, Pedro Alves wrote:
>> Why does GDB need to touch the shell's registers at all in the first place?
>
> I haven't checked why.
Well, I claim that it shouldn't. :-) The whole existence of
fork-child.c:startup_inferior was justified on making GDB not touch the
shell. We used to have the startup phase go through the whole
wait_for_inferior shebang, which was problematic as it touched the shell.
>
>> If we can't skip darwin_set_sstep for all continues that are not single-steps,
>> we could at least skip those while starting up (when continuing the shell
>> until we see enough execs). That'd suggest a new flag like
>> darwin-nat.h:struct private_inferior->starting_up, set and cleared in
>> darwin_create_inferior, and then making darwin_resume_thread do:
>>
>> - /* Set single step. */
>> - inferior_debug (4, _("darwin_set_sstep (thread=%x, enable=%d)\n"),
>> - thread->gdb_port, step);
>> - darwin_set_sstep (thread->gdb_port, step);
>> + /* Avoid touching the $SHELL process, and go straight to resuming it. */
>> + gdb_assert (!inf->private->starting_up || !step);
>> + if (!inf->private->starting_up)
>> + {
>> + /* Set single step. */
>> + inferior_debug (4, _("darwin_set_sstep (thread=%x, enable=%d)\n"),
>> + thread->gdb_port, step);
>> + darwin_set_sstep (thread->gdb_port, step);
>>
>> WDYT?
>
> Yes, it might be cleaner.
>
> Honestly, I'd prefer to get rid of the shell step and directly execute the user program - or at least have an option to do that. I think I also understand the cons of this approach.
I'd be glad to see STARTUP_WITH_SHELL turned into a run-time option. I think there's
a PR open for that even. However, we need the shell at least for argument globbing,
as in, e.g., debugging `ls *', so I don't think we could make it off by default,
which practically renders it an orthogonal feature.
--
Pedro Alves
next prev parent reply other threads:[~2012-04-02 14:17 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-30 13:42 PR13901 Jack Howarth
2012-03-30 14:19 ` PR13901 Tristan Gingold
2012-04-02 10:44 ` PR13901 Tristan Gingold
2012-04-02 11:57 ` PR13901 Tristan Gingold
2012-04-02 13:17 ` PR13901 Jack Howarth
2012-04-02 13:22 ` PR13901 Tristan Gingold
2012-04-02 13:56 ` PR13901 Pedro Alves
2012-04-02 14:07 ` PR13901 Tristan Gingold
2012-04-02 14:17 ` Pedro Alves [this message]
2012-04-02 14:25 ` PR13901 Tristan Gingold
2012-04-02 14:59 ` PR13901 Andreas Schwab
2012-04-02 15:08 ` PR13901 Tristan Gingold
2012-04-02 15:23 ` PR13901 Pedro Alves
2012-04-02 16:22 ` PR13901 Andreas Schwab
2012-04-02 16:31 ` PR13901 Pedro Alves
2012-04-02 17:28 ` PR13901 Andreas Schwab
2012-04-03 7:28 ` PR13901 John Gilmore
2012-04-04 14:23 ` PR13901 Pedro Alves
2012-04-04 14:47 ` PR13901 Tristan Gingold
2012-04-04 15:01 ` PR13901 Pedro Alves
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