RE: [PATCH] PR61868

[Bingfeng Mei <bmei at broadcom dot com>]

Yes, that fix is better. Here are updated patches. LTO-bootstrapped and tested. OK?

Bingfeng

Index: ChangeLog
===================================================================
--- ChangeLog   (revision 213152)
+++ ChangeLog   (working copy)
@@ -1,3 +1,10 @@
+2014-07-29  Bingfeng Mei <bmei@broadcom.com>
+
+       PR lto/61868
+       * toplev.c (init_random_seed): Move piece of code never called to
+       set_random_seed.
+       (set_random_seed): see above.
+
 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)
@@ -282,16 +282,7 @@ init_local_tick (void)
 static void
 init_random_seed (void)
 {
-  if (flag_random_seed)
-    {
-      char *endp;
-
-      /* When the driver passed in a hex number don't crc it again */
-      random_seed = strtoul (flag_random_seed, &endp, 0);
-      if (!(endp > flag_random_seed && *endp == 0))
-        random_seed = crc32_string (0, flag_random_seed);
-    }
-  else if (!random_seed)
+  if (!random_seed)
     random_seed = local_tick ^ getpid ();  /* Old racey fallback method */
 }

@@ -314,6 +305,15 @@ set_random_seed (const char *val)
 {
   const char *old = flag_random_seed;
   flag_random_seed = val;
+  if (flag_random_seed)
+    {
+      char *endp;
+
+      /* When the driver passed in a hex number don't crc it again */
+      random_seed = strtoul (flag_random_seed, &endp, 0);
+      if (!(endp > flag_random_seed && *endp == 0))
+        random_seed = crc32_string (0, flag_random_seed);
+    }
   return old;
 }

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" } } */

> -----Original Message-----
> From: Richard Biener [mailto:richard.guenther@gmail.com]
> Sent: 30 July 2014 14:08
> To: Bingfeng Mei
> Cc: Andi Kleen; gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] PR61868
> 
> On Wed, Jul 30, 2014 at 2:48 PM, Bingfeng Mei <bmei@broadcom.com> wrote:
> > 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;
> > }
> 
> I think it makes more sense to move the if (flag_random_seed)
> code from init_random_seed inline here as init_random_seed is
> never called with flag_random_set == true.
> 
> Richard.
> 
> > 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" } } */
> >> >> >