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.guent...@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 <b...@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.guent...@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 <b...@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 <b...@broadcom.com> > >> > + > >> > + PR lto/61868 > >> > + * toplev.c (init_random_seed): Generate random seed when > >> > + flag_random_seed is specified. > >> > + > >> > 2014-07-28 Jan Hubicka <hubi...@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 <b...@broadcom.com> > >> > + > >> > + PR lto/61868 > >> > + * gcc.dg/pr61868.c: New test. > >> > + > >> > 2014-07-28 Richard Biener <rguent...@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" } } */ > >> >