[PATCH] malloc: obscure calloc use in tst-calloc

[Andreas K. Huettel]

Am Freitag, 10. Januar 2025, 04:40:31 Mitteleuropäische Normalzeit schrieb H.J. Lu:
> On Fri, Jan 10, 2025, 11:12 AM Sam James <sam@gentoo.org> wrote:
> 
> > Similar to a9944a52c967ce76a5894c30d0274b824df43c7a and
> > f9493a15ea9cfb63a815c00c23142369ec09d8ce, we need to hide calloc use from
> > the compiler to accommodate GCC's r15-6566-g804e9d55d9e54c change.
> >
> > First, include tst-malloc-aux.h, but then use `volatile` variables
> > for size.
> >
> > The test passes without the tst-malloc-aux.h change but IMO we want
> > it there for consistency and to avoid future problems (possibly silent).

OK for 2.41 (test improvement)

> > ---
> >  malloc/tst-calloc.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/malloc/tst-calloc.c b/malloc/tst-calloc.c
> > index 77a32f8052..122b2cbeaf 100644
> > --- a/malloc/tst-calloc.c
> > +++ b/malloc/tst-calloc.c
> > @@ -23,6 +23,7 @@
> >  #include <stdio.h>
> >  #include <libc-diag.h>
> >
> > +#include "tst-malloc-aux.h"
> >
> >  /* Number of samples per size.  */
> >  #define N 50000
> > @@ -94,16 +95,19 @@ random_test (void)
> >  static void
> >  null_test (void)
> >  {
> > +  /* Obscure allocation size from the compiler.  */
> > +  volatile size_t max_size = UINT_MAX;
> > +  volatile size_t zero_size = 0;
> >    /* If the size is 0 the result is implementation defined.  Just make
> >       sure the program doesn't crash.  The result of calloc is
> >       deliberately ignored, so do not warn about that.  */
> >    DIAG_PUSH_NEEDS_COMMENT;
> >    DIAG_IGNORE_NEEDS_COMMENT (10, "-Wunused-result");
> >    calloc (0, 0);
> > -  calloc (0, UINT_MAX);
> > -  calloc (UINT_MAX, 0);
> > -  calloc (0, ~((size_t) 0));
> > -  calloc (~((size_t) 0), 0);
> > +  calloc (0, max_size);
> > +  calloc (max_size, 0);
> > +  calloc (0, ~((size_t) zero_size));
> > +  calloc (~((size_t) zero_size), 0);
> >    DIAG_POP_NEEDS_COMMENT;
> >  }
> >
> >
> > base-commit: dad44389f2f96523080e3b105eee1b1ab8b19722
> > prerequisite-patch-id: 6bc066b9be8e3c65fae35848708646513d151266
> > --
> > 2.48.0.rc2
> >
> 
> LGTM.
> 
> Thanks.
> 
> 
> >
> >
> 


-- 
PD Dr. Andreas K. Huettel
Institute for Experimental and Applied Physics
University of Regensburg
93040 Regensburg
Germany

tel. +49 151 241 67748 (mobile)
tel. +49 941 943 1618 (office)
e-mail andreas.huettel@ur.de
https://www.akhuettel.de/
https://www.akhuettel.de/group/
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