From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-return-21845-listarch-gdb=sources.redhat.com@sources.redhat.com>
Received: (qmail 18468 invoked by alias); 14 Jun 2005 09:23:43 -0000
Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm
Precedence: bulk
List-Subscribe: <mailto:gdb-subscribe@sources.redhat.com>
List-Archive: <http://sources.redhat.com/ml/gdb/>
List-Post: <mailto:gdb@sources.redhat.com>
List-Help: <mailto:gdb-help@sources.redhat.com>, <http://sources.redhat.com/ml/#faqs>
Sender: gdb-owner@sources.redhat.com
Received: (qmail 18445 invoked by uid 22791); 14 Jun 2005 09:23:35 -0000
Received: from main.gmane.org (HELO ciao.gmane.org) (80.91.229.2)
    by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Tue, 14 Jun 2005 09:23:35 +0000
Received: from list by ciao.gmane.org with local (Exim 4.43)
	id 1Di7Ye-0005Xl-LP
	for gdb@sources.redhat.com; Tue, 14 Jun 2005 11:18:08 +0200
Received: from zigzag.lvk.cs.msu.su ([158.250.17.23])
        by main.gmane.org with esmtp (Gmexim 0.1 (Debian))
        id 1AlnuQ-0007hv-00
        for <gdb@sources.redhat.com>; Tue, 14 Jun 2005 11:18:08 +0200
Received: from ghost by zigzag.lvk.cs.msu.su with local (Gmexim 0.1 (Debian))
        id 1AlnuQ-0007hv-00
        for <gdb@sources.redhat.com>; Tue, 14 Jun 2005 11:18:08 +0200
To: gdb@sources.redhat.com
From:  Vladimir Prus <ghost@cs.msu.su>
Subject:  problem debugging assembler functions
Date: Tue, 14 Jun 2005 09:23:00 -0000
Message-ID:  <d8m7a8$akn$1@sea.gmane.org>
Mime-Version:  1.0
Content-Type:  text/plain; charset=us-ascii
Content-Transfer-Encoding:  7Bit
User-Agent: KNode/0.8.2
X-SW-Source: 2005-06/txt/msg00128.txt.bz2


Hello,
I'm trying to port gdb to a new architecture (with it's own compiler), and
run into problems with assembler functions. I can successfully step into
an assembler function, but when I run "step", instead of moving to the 
next instruction, gdb sets breakpoint at return address and continues.
Looking at the code, I see this (in infrun.c)

Line 2285:

 if (frame_id_eq (frame_unwind_id (get_current_frame ()), step_frame_id))
 {
     ......
 }

Line 2428:

 if (step_over_calls == STEP_OVER_UNDEBUGGABLE
      && ecs->stop_func_name == NULL)
  {
       /* The inferior just stepped into, or returned to, an
         undebuggable function (where there is no symbol, not even a
         minimal symbol, corresponding to the address where the
         inferior stopped). 
        */

        ........

        insert_step_resume_breakpoint_at_frame (
             get_prev_frame (get_current_frame ()));  
  }


The condition is the second code block is taken and breakpoint is indeed
set. I have two questions:

1. Is "just stepped into ... function" comment accurate? I think that all
cases of steppin into function are handled by the previous

 if (frame_id_eq (frame_unwind_id (get_current_frame ()), step_frame_id)) {}

condition, and all code paths inside that condition end with return. So, the
second code block is not executed when we've just stepped into a function.
Is the code intended to handle only the case when we've *returned* to
undebuggable function?

2. In my case, no function names for assembler modules are present in debug
info, but line information is there, so the function is debuggable. Is
there a way to check of line info in condition, not for function name?

Thanks in advance,
Volodya