Re: RFA: Actual support for tracing forks on GNU/Linux

Daniel Jacobowitz
2003-08-18T12:59:45Z

On Mon, Aug 18, 2003 at 11:09:53AM +0200, Michal Ludvig wrote:
> Daniel Jacobowitz told me that:
>
> > 2003-08-17 Daniel Jacobowitz <drow@mvista.com>
> >
> > * config/i386/nm-linux.h (LINUX_CHILD_POST_STARTUP_INFERIOR):
> > Define.
> > * i386-linux-nat.c: Include "linux-nat.h".
> > (child_post_startup_inferior): New function.
> > * i386-nat.c (child_post_startup_inferior): Wrap in #ifdef.
> > * linux-nat.c (linux_enable_event_reporting): New function.
> > (child_post_attach, linux_child_post_startup_inferior)
> > (child_post_startup_inferior, child_follow_fork)
> > (linux_handle_extended_wait, kill_inferior): New functions.
>
> Hi Daniel,
> this change broke build on AMD64. Per-se I'm getting linker error:
>
> libgdb.a(linux-nat.o)(.text+0x3e8): In function
> `child_post_startup_inferior':
> ../../gdb-6.0/gdb/linux-nat.c:223: multiple definition of
> `child_post_startup_inferior'
> libgdb.a(i386-nat.o)(.text+0x52):../../gdb-6.0/gdb/i386-nat.c:238: first
> defined here
> /usr/lib64/gcc-lib/x86_64-suse-linux/3.3/../../../../x86_64-suse-linux/bin/ld:
> Warning: size of symbol `child_post_startup_inferior' changed from 11 in
> libgdb.a(i386-nat.o) to 41 in libgdb.a(i386-nat.o)
> collect2: ld returned 1 exit status
> make: *** [gdb] Error 1
>
> I.e. `child_post_startup_inferior' is defined twice.
>
> When I define LINUX_CHILD_POST_STARTUP_INFERIOR in
> config/i386/nm-x86-64linux.h I get:
>
> libgdb.a(inftarg.o)(.text+0x692): In function `init_child_ops':
> ../../gdb-6.0/gdb/inftarg.c:593: undefined reference to
> `child_post_startup_inferior'
> libgdb.a(lin-lwp.o)(.text+0x3f76): In function `init_lin_lwp_ops':
> ../../gdb-6.0/gdb/lin-lwp.c:1675: undefined reference to
> `child_post_startup_inferior'
>
> I.e. it's never defined.
>
> The problem seems to be that child_post_startup_inferior() in both
> i386-nat.c and linux-nat.c is #ifNdef-ed, i.e. either both undefined or
> both defined. Is that intended?

Take a look at the third copy - it's in i386-linux-nat.c. Then take a
look at the annoyed comment in i386/nm-linux.h.

> However the proper fix for amd64 seems to be:
>
> Index: x86-64-linux-nat.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/x86-64-linux-nat.c,v
> retrieving revision 1.23.6.2
> diff -u -p -r1.23.6.2 x86-64-linux-nat.c
> --- x86-64-linux-nat.c 17 Jul 2003 12:51:55 -0000 1.23.6.2
> +++ x86-64-linux-nat.c 18 Aug 2003 09:05:51 -0000
> @@ -347,3 +347,9 @@ ps_get_thread_area (const struct ps_proc
> return PS_ERR; /* ptrace failed. */
> }
>
> +void
> +child_post_startup_inferior (ptid_t ptid)
> +{
> + i386_cleanup_dregs ();
> + linux_child_post_startup_inferior (ptid);
> +}
>
> Right? OK to apply?

Along with defining LINUX_CHILD_POST_STARTUP_INFERIOR, I assume? Yes,
this is OK. Sorry about breaking amd64.