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List:       gdb
Subject:    RE: Dummy Breakpoint Priority
From:       "Thomas,Stephen" <stephen.thomas () superh ! com>
Date:       2003-06-27 8:14:25
Message-ID: 9FF3133289A7A84E81E2ED8F5E56B379604399 () sh-uk-ex01 ! uk ! w2k ! superh ! com
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Hi Andrew,

In the version I'm using (V5.2.1), i386 used ON_STACK. I actually verified (using \
gdb!) that x86 gdb really did set a bp of type bp_shlib_event at _start.

But I just checked the latest sources, & can't find a setting anywhere for call dummy \
location. So it looks like i386 uses the default, i.e. AT_ENTRY_POINT (now set in \
gdbarch.c). Can you verify that the latest gdb doesn't suffer from the same problem? \
To reproduce, you need to call function in a statically linked program.

Thanks,

Steve Thomas
SuperH (UK) Ltd.

-----Original Message-----
From: Andrew Cagney [mailto:ac131313@redhat.com] 
Sent: 26 June 2003 18:47
To: Thomas,Stephen
Cc: gdb@sources.redhat.com; Bowers, Antony; McGoogan,Sean
Subject: Re: Dummy Breakpoint Priority


> Hi,
> 
> I am currently porting gdb to the new SuperH SH5 architecture. I have 
> just hit a problem, which sounds exactly the same as that reported on 
> 31 Aug 2001 (by Jiri Smid, titled 'Dummy Breakpoint Priority').
> 
> When a target function is called from the command line, a special 
> dummy breakpoint is inserted at the program entry point. (We have 
> CALL_DUMMY_LOCATION defined as AT_ENTRY_POINT). Trouble is, when the 
> program is statically linked, gdb has already placed an internal 
> breakpoint at _start, of type bp_shlib_event. On return from the 
> function, this causes bpstat_what() in breakpoint.c to return an 
> action which causes gdb to carry on executing (what.main_action = 
> BPSTAT_WHAT_CHECK_SHLIBS).
> 
> The reply to Jiri Smid's mail asked why solib-svr4.c was setting a bp 
> on the entry point. But it looks like this is the normal thing for gdb 
> to do - I verified that x86 gdb does the same thing (it doesn't suffer 
> from this problem though because it doesn't use AT_ENTRY_POINT).

Are you sure that the i386 isn't using at AT_ENTRY_POINT?

> So please can anyone tell me what the resolution of this problem was?
> NB: Please reply using 'Reply All' as I am leaving SuperH shortly...

I'm puzzled to.

Andrew


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