[PATCH] PR61868

[Bingfeng Mei]

On the second thought, maybe the change should be made in set_random_seed. Otherwise, init_random_seed is invoked every time get_random_seed get called (not sure how often). What do you think? 

const char *
set_random_seed (const char *val)
{
  const char *old = flag_random_seed;
  flag_random_seed = val;
+ init_random_seed ();
  return old;
}

Bingfeng

> -----Original Message-----
> From: Richard Biener [mailto:richard.guenther@gmail.com]
> Sent: 30 July 2014 10:43
> To: Bingfeng Mei
> Cc: Andi Kleen; gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] PR61868
> 
> On Wed, Jul 30, 2014 at 10:52 AM, Bingfeng Mei <bmei@broadcom.com> wrote:
> > Yes, opts-global.c fills flag_random_seed with string passed in
> command line. But init_random_seed in toplev.c is the one that processes
> the flag and set random_seed variable, which is returned by
> get_random_seed function.
> 
> Err, I meant opts-global.c:handle_common_deferred_options
> 
> > By default, my configuration enables LTO. How to test LTO bootstrap?
> 
> configure with --with-build-config=bootstrap-lto (and reduce the
> set of languages to c,c++ to get a sane bootstrap time).
> 
> Richard.
> 
> > Bingfeng
> >
> >> -----Original Message-----
> >> From: Richard Biener [mailto:richard.guenther@gmail.com]
> >> Sent: 30 July 2014 08:47
> >> To: Bingfeng Mei; Andi Kleen
> >> Cc: gcc-patches@gcc.gnu.org
> >> Subject: Re: [PATCH] PR61868
> >>
> >> On Tue, Jul 29, 2014 at 3:01 PM, Bingfeng Mei <bmei@broadcom.com>
> wrote:
> >> > Hi,
> >> > Please find the patches for pr61868. The problem is that even with
> -
> >> frandom-seed gcc always uses 0 instead of specified number/string for
> >> places such as lto section names. init_random_seed is never called
> with
> >> -frandom-seed. Bootstrapped and tested on x86-64. OK for trunk?
> >>
> >> Hmm, but -frandom-seed= is honored by opts.c calling set_random_seed?
> >>
> >> Andi, wasn't this used to support partial linking of LTO objects?
> Thus,
> >> this shortcut was on purpose?  Otherwise passing -frandom-seed to
> >> LTO would break that?
> >>
> >> Bingfeng, did you test if LTO bootstrap still works after this patch?
> >>
> >> Thanks,
> >> Richard.
> >>
> >> > Thanks,
> >> > Bingfeng Mei
> >> >
> >> >
> >> > ===================================================================
> >> > --- ChangeLog   (revision 213152)
> >> > +++ ChangeLog   (working copy)
> >> > @@ -1,3 +1,9 @@
> >> > +2014-07-29  Bingfeng Mei <bmei@broadcom.com>
> >> > +
> >> > +       PR lto/61868
> >> > +       * toplev.c (init_random_seed): Generate random seed when
> >> > +       flag_random_seed is specified.
> >> > +
> >> >  2014-07-28  Jan Hubicka  <hubicka@ucw.cz>
> >> >
> >> >         * cgraph.c (cgraph_node::create_indirect_edge): Copy
> >> speculative data.
> >> > Index: toplev.c
> >> > ===================================================================
> >> > --- toplev.c    (revision 213152)
> >> > +++ toplev.c    (working copy)
> >> > @@ -301,7 +301,7 @@ init_random_seed (void)
> >> >  HOST_WIDE_INT
> >> >  get_random_seed (bool noinit)
> >> >  {
> >> > -  if (!flag_random_seed && !noinit)
> >> > +  if (!noinit)
> >> >      init_random_seed ();
> >> >    return random_seed;
> >> >  }
> >> > Index: testsuite/ChangeLog
> >> > ===================================================================
> >> > --- testsuite/ChangeLog (revision 213152)
> >> > +++ testsuite/ChangeLog (working copy)
> >> > @@ -1,3 +1,8 @@
> >> > +2014-07-29  Bingfeng Mei  <bmei@broadcom.com>
> >> > +
> >> > +       PR lto/61868
> >> > +       * gcc.dg/pr61868.c: New test.
> >> > +
> >> >  2014-07-28  Richard Biener  <rguenther@suse.de>
> >> >
> >> >         PR rtl-optimization/61801
> >> > Index: testsuite/gcc.dg/pr61868.c
> >> > ===================================================================
> >> > --- testsuite/gcc.dg/pr61868.c  (revision 0)
> >> > +++ testsuite/gcc.dg/pr61868.c  (revision 0)
> >> > @@ -0,0 +1,9 @@
> >> > +/* { dg-do compile } */
> >> > +/* { dg-options "-flto -frandom-seed=0x12345" }  */
> >> > +extern int foo (int);
> >> > +int main ()
> >> > +{
> >> > +  foo (100);
> >> > +  return 0;
> >> > +}
> >> > +/* { dg-final { scan-assembler "\.gnu\.lto.*.12345" } } */
> >> >