[v2,1/2] x86-64: Test strlen and wcslen with 0 in the RSI register [BZ #28064]

  From: "H.J. Lu" <hjl.tools@gmail.com>

commit 6f573a27b6c8b4236445810a44660612323f5a73
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Wed Jun 23 01:19:34 2021 -0400

    x86-64: Add wcslen optimize for sse4.1

added wcsnlen-sse4.1 to the wcslen ifunc implementation list.  Since the
random value in the the RSI register is larger than the wide-character
string length in the existing wcslen test, it didn't trigger the wcslen
test failure.  Add a test to force 0 into the RSI register before calling
wcslen.
---
 sysdeps/x86_64/Makefile         |  7 +++
 sysdeps/x86_64/tst-rsi-strlen.c | 81 +++++++++++++++++++++++++++++++++
 sysdeps/x86_64/tst-rsi-wcslen.c | 20 ++++++++
 3 files changed, 108 insertions(+)
 create mode 100644 sysdeps/x86_64/tst-rsi-strlen.c
 create mode 100644 sysdeps/x86_64/tst-rsi-wcslen.c
  

On Thu, Jul 8, 2021 at 1:13 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> From: "H.J. Lu" <hjl.tools@gmail.com>
>
> commit 6f573a27b6c8b4236445810a44660612323f5a73
> Author: Noah Goldstein <goldstein.w.n@gmail.com>
> Date:   Wed Jun 23 01:19:34 2021 -0400
>
>     x86-64: Add wcslen optimize for sse4.1
>
> added wcsnlen-sse4.1 to the wcslen ifunc implementation list.  Since the
> random value in the the RSI register is larger than the wide-character
> string length in the existing wcslen test, it didn't trigger the wcslen
> test failure.  Add a test to force 0 into the RSI register before calling
> wcslen.
> ---
>  sysdeps/x86_64/Makefile         |  7 +++
>  sysdeps/x86_64/tst-rsi-strlen.c | 81 +++++++++++++++++++++++++++++++++
>  sysdeps/x86_64/tst-rsi-wcslen.c | 20 ++++++++
>  3 files changed, 108 insertions(+)
>  create mode 100644 sysdeps/x86_64/tst-rsi-strlen.c
>  create mode 100644 sysdeps/x86_64/tst-rsi-wcslen.c
>
> diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
> index 06a444b6af..3fc03f4a19 100644
> --- a/sysdeps/x86_64/Makefile
> +++ b/sysdeps/x86_64/Makefile
> @@ -20,6 +20,8 @@ endif
>  ifeq ($(subdir),string)
>  sysdep_routines += strcasecmp_l-nonascii strncase_l-nonascii
>  gen-as-const-headers += locale-defines.sym
> +tests += \
> +  tst-rsi-strlen
>  endif
>
>  ifeq ($(subdir),elf)
> @@ -191,6 +193,11 @@ ifeq ($(subdir),csu)
>  gen-as-const-headers += tlsdesc.sym rtld-offsets.sym
>  endif
>
> +ifeq ($(subdir),wcsmbs)
> +tests += \
> +  tst-rsi-wcslen
> +endif
> +
>  $(objpfx)x86_64/tst-x86_64mod-1.os: $(objpfx)tst-x86_64mod-1.os
>         $(make-target-directory)
>         rm -f $@
> diff --git a/sysdeps/x86_64/tst-rsi-strlen.c b/sysdeps/x86_64/tst-rsi-strlen.c
> new file mode 100644
> index 0000000000..a80c4f85c2
> --- /dev/null
> +++ b/sysdeps/x86_64/tst-rsi-strlen.c
> @@ -0,0 +1,81 @@
> +/* Test strlen with 0 in the RSI register.
> +   Copyright (C) 2021 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#ifdef WIDE
> +# define TEST_NAME "wcslen"
> +#else
> +# define TEST_NAME "strlen"
> +#endif /* WIDE */
> +
> +#define TEST_MAIN
> +#include <string/test-string.h>
> +
> +#ifdef WIDE
> +# include <wchar.h>
> +# define STRLEN wcslen
> +# define CHAR wchar_t
> +#else
> +# define STRLEN strlen
> +# define CHAR char
> +#endif /* WIDE */
> +
> +IMPL (STRLEN, 1)
> +
> +typedef size_t (*proto_t) (const CHAR *);
> +
> +typedef struct
> +{
> +  void (*fn) (void);
> +} parameter_t;
> +
> +size_t
> +__attribute__ ((weak, noinline, noclone))
> +do_strlen (parameter_t *a, int zero, const CHAR *str)
> +{
> +  return CALL (a, str);
> +}
> +
> +static int
> +test_main (void)
> +{
> +  test_init ();
> +
> +  size_t size = page_size / sizeof (CHAR) - 1;
> +  CHAR *buf = (CHAR *) buf2;
> +  buf[size] = 0;
> +
> +  parameter_t a;
> +
> +  int ret = 0;
> +  FOR_EACH_IMPL (impl, 0)
> +    {
> +      a.fn = impl->fn;
> +      /* NB: Pass 0 in RSI.  */
> +      size_t res = do_strlen (&a, 0, buf);
> +      if (res != size)
> +       {
> +         error (0, 0, "Wrong result in function %s: %zu != %zu",
> +                impl->name, res, size);
> +         ret = 1;
> +       }
> +    }
> +
> +  return ret ? EXIT_FAILURE : EXIT_SUCCESS;
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/sysdeps/x86_64/tst-rsi-wcslen.c b/sysdeps/x86_64/tst-rsi-wcslen.c
> new file mode 100644
> index 0000000000..f45a7dfb51
> --- /dev/null
> +++ b/sysdeps/x86_64/tst-rsi-wcslen.c
> @@ -0,0 +1,20 @@
> +/* Test wcslen with 0 in the RSI register.
> +   Copyright (C) 2021 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define WIDE 1
> +#include "tst-rsi-strlen.c"
> --
> 2.25.1
>

I am backporting this patch to release branches.