Re: [PATCH] Added Redirects to longdouble error functions [BZ #29033]

[Sachin Monga <smonga@linux.ibm.com>]

I am working on the updated patch as I can see that CI is failing with 
this patch.


On 13/04/23 11:18 pm, Sachin Monga wrote:
> This patch redirects the error functions to the appropriate
> longdouble variants which enables the compiler to optimize
> for the abi ieeelongdouble.
>
> Signed-off-by: Sachin Monga <smonga@linux.ibm.com>
> ---
>   misc/Makefile                               |  2 +-
>   misc/bits/error-ldbl.h                      | 45 ++++++++++
>   misc/sys/cdefs.h                            |  3 +-
>   misc/tst-ldbl-errorfptr.c                   | 91 +++++++++++++++++++++
>   sysdeps/ieee754/ldbl-128ibm-compat/Makefile |  2 +
>   sysdeps/ieee754/ldbl-opt/Makefile           |  4 +
>   6 files changed, 145 insertions(+), 2 deletions(-)
>   create mode 100644 misc/tst-ldbl-errorfptr.c
>
> diff --git a/misc/Makefile b/misc/Makefile
> index 1a09f777fa..9f42321206 100644
> --- a/misc/Makefile
> +++ b/misc/Makefile
> @@ -90,7 +90,7 @@ tests := tst-dirname tst-tsearch tst-fdset tst-mntent tst-hsearch \
>   	 tst-preadvwritev2 tst-preadvwritev64v2 tst-warn-wide \
>   	 tst-ldbl-warn tst-ldbl-error tst-dbl-efgcvt tst-ldbl-efgcvt \
>   	 tst-mntent-autofs tst-syscalls tst-mntent-escape tst-select \
> -	 tst-ioctl
> +	 tst-ioctl tst-ldbl-errorfptr
>   
>   tests-time64 := \
>     tst-select-time64 \
> diff --git a/misc/bits/error-ldbl.h b/misc/bits/error-ldbl.h
> index 599a7d6e06..bbc4956f68 100644
> --- a/misc/bits/error-ldbl.h
> +++ b/misc/bits/error-ldbl.h
> @@ -20,5 +20,50 @@
>   # error "Never include <bits/error-ldbl.h> directly; use <error.h> instead."
>   #endif
>   
> +#if defined __extern_always_inline && defined __va_arg_pack
> +extern void __REDIRECT_LDBL (__error_alias, (int __status, int __errnum,
> +			     const char *__format, ...), error)
> +  __attribute__ ((__format__ (__printf__, 3, 4)));
> +extern void __REDIRECT_LDBL (__error_noreturn, (int __status, int __errnum,
> +			     const char *__format, ...), error)
> +  __attribute__ ((__noreturn__, __format__ (__printf__, 3, 4)));
> +
> +
> +/* If we know the function will never return make sure the compiler
> +   realizes that, too.  */
> +__extern_always_inline void
> +error (int __status, int __errnum, const char *__format, ...)
> +{
> +  if (__builtin_constant_p (__status) && __status != 0)
> +    __error_noreturn (__status, __errnum, __format, __va_arg_pack ());
> +  else
> +    __error_alias (__status, __errnum, __format, __va_arg_pack ());
> +}
> +
> +
> +extern void __REDIRECT_LDBL (__error_at_line_alias, (int __status, int __errnum,
> +			     const char *__fname, unsigned int __line,
> +			     const char *__format, ...), error_at_line)
> +  __attribute__ ((__format__ (__printf__, 5, 6)));
> +extern void __REDIRECT_LDBL (__error_at_line_noreturn, (int __status, int __errnum,
> +			     const char *__fname, unsigned int __line,
> +			     const char *__format, ...), error_at_line)
> +  __attribute__ ((__noreturn__, __format__ (__printf__, 5, 6)));
> +
> +
> +/* If we know the function will never return make sure the compiler
> +   realizes that, too.  */
> +__extern_always_inline void
> +error_at_line (int __status, int __errnum, const char *__fname,
> +	       unsigned int __line, const char *__format, ...)
> +{
> +  if (__builtin_constant_p (__status) && __status != 0)
> +    __error_at_line_noreturn (__status, __errnum, __fname, __line, __format,
> +			      __va_arg_pack ());
> +  else
> +    __error_at_line_alias (__status, __errnum, __fname, __line,
> +			   __format, __va_arg_pack ());
> +}
> +#endif
>   __LDBL_REDIR_DECL (error)
>   __LDBL_REDIR_DECL (error_at_line)
> diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
> index 23ec0ebd2a..285191482a 100644
> --- a/misc/sys/cdefs.h
> +++ b/misc/sys/cdefs.h
> @@ -569,6 +569,8 @@
>   #  define __LDBL_REDIR(name, proto) ... unused__ldbl_redir
>   #  define __LDBL_REDIR_DECL(name) \
>     extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
> +#  define __REDIRECT_LDBL(name, proto, alias) \
> +  name proto __asm (__ASMNAME ("__" #alias "ieee128"))
>   
>   /* Alias name defined automatically, with leading underscores.  */
>   #  define __LDBL_REDIR2_DECL(name) \
> @@ -586,7 +588,6 @@
>     __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128)
>   
>   /* Unused.  */
> -#  define __REDIRECT_LDBL(name, proto, alias) ... unused__redirect_ldbl
>   #  define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth
>   
>   # else
> diff --git a/misc/tst-ldbl-errorfptr.c b/misc/tst-ldbl-errorfptr.c
> new file mode 100644
> index 0000000000..67b50c687f
> --- /dev/null
> +++ b/misc/tst-ldbl-errorfptr.c
> @@ -0,0 +1,91 @@
> +/* Test for the long double redirections in error* functions
> +   when they are returned as function pointer BZ #29033.
> +   Copyright (C) 2023 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/>.  */
> +
> +#include <err.h>
> +#include <errno.h>
> +#include <error.h>
> +#include <stdarg.h>
> +#include <string.h>
> +#include <stdlib.h>
> +#include <dlfcn.h>
> +#include <sys/cdefs.h>
> +
> +#include <support/capture_subprocess.h>
> +#include <support/check.h>
> +#include <support/xdlfcn.h>
> +
> +#define NLDBL_SYMBOL2(alias) __ASMNAME (#alias)
> +#define NLDBL_SYMBOL(alias) NLDBL_SYMBOL2 (__nldbl_##alias)
> +#define IEEE_LONG_DOUBLE(alias) __ASMNAME ("__" #alias "ieee128")
> +#define NO_LONG_DOUBLE(alias) NLDBL_SYMBOL (alias)
> +
> +typedef void (*error_func_t) (int, int, const char*, ...);
> +typedef void (*error_at_line_func_t) (int, int, const char*,
> +	      unsigned int, const char*, ...);
> +
> +error_func_t
> +__attribute__ ((noinline))
> +get_error_func (void) {
> +  return &error;
> +}
> +
> +error_at_line_func_t
> +__attribute__ ((noinline))
> +get_error_at_line_func (void) {
> +  return &error_at_line;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  /* Prepare the symbol names as per long double standards */
> +  char *error_sym = NULL;
> +  char *error_sym_at_line = NULL;
> +#if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
> +  error_sym = (char *) IEEE_LONG_DOUBLE(error);
> +  error_sym_at_line = (char *) IEEE_LONG_DOUBLE(error_at_line);
> +#elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
> +  error_sym = (char *) NO_LONG_DOUBLE(error);
> +  error_sym_at_line = (char *) NO_LONG_DOUBLE(error_at_line);
> +#else
> +  FAIL_EXIT1 ("test case error");
> +#endif
> +  TEST_VERIFY (error_sym != NULL && error_sym_at_line != NULL);
> +  /* Map the function pointers to appropriate redirected error symbols */
> +  error_func_t fp;
> +  fp = get_error_func ();
> +  if (fp != xdlsym (RTLD_DEFAULT, error_sym))
> +    {
> +      printf ("FAIL: fp=%p error_sym=%p\n", fp, error_sym);
> +      return 1;
> +    }
> +
> +  error_at_line_func_t fpat;
> +  fpat = get_error_at_line_func ();
> +  if (fpat != xdlsym (RTLD_DEFAULT, error_sym_at_line))
> +    {
> +      printf ("FAIL: fpat=%p error_sym_at_line=%p\n",
> +	      fpat, error_sym_at_line);
> +      return 1;
> +    }
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/Makefile b/sysdeps/ieee754/ldbl-128ibm-compat/Makefile
> index d4ec41bf99..42cca25a09 100644
> --- a/sysdeps/ieee754/ldbl-128ibm-compat/Makefile
> +++ b/sysdeps/ieee754/ldbl-128ibm-compat/Makefile
> @@ -264,6 +264,7 @@ CFLAGS-ieee128-qefgcvt_r.c += -mabi=ieeelongdouble -Wno-psabi -mno-gnu-attribute
>   tests-internal += tst-ibm128-warn tst-ieee128-warn
>   tests-internal += tst-ibm128-error tst-ieee128-error
>   tests-internal += tst-ibm128-efgcvt tst-ieee128-efgcvt
> +tests-internal += tst-ieee128-errorfptr
>   
>   $(objpfx)tst-ibm128-%.c: tst-ldbl-%.c
>   	cp $< $@
> @@ -278,6 +279,7 @@ CFLAGS-tst-ibm128-efgcvt.c += -mabi=ibmlongdouble -Wno-psabi
>   CFLAGS-tst-ieee128-warn.c += -mfloat128 -mabi=ieeelongdouble -Wno-psabi
>   CFLAGS-tst-ieee128-error.c += -mfloat128 -mabi=ieeelongdouble -Wno-psabi
>   CFLAGS-tst-ieee128-efgcvt.c += -mfloat128 -mabi=ieeelongdouble -Wno-psabi
> +CFLAGS-tst-ieee128-errorfptr.c += -mfloat128 -mabi=ieeelongdouble -Wno-psabi
>   
>   tests-container += test-syslog-ieee128 test-syslog-ibm128
>   CFLAGS-test-syslog-ieee128.c += -mfloat128 -mabi=ieeelongdouble -Wno-psabi
> diff --git a/sysdeps/ieee754/ldbl-opt/Makefile b/sysdeps/ieee754/ldbl-opt/Makefile
> index 5b72474aa4..22e778ad0e 100644
> --- a/sysdeps/ieee754/ldbl-opt/Makefile
> +++ b/sysdeps/ieee754/ldbl-opt/Makefile
> @@ -215,6 +215,7 @@ endif
>   ifeq ($(subdir), misc)
>   tests-internal += tst-nldbl-warn
>   tests-internal += tst-nldbl-error
> +tests-internal += tst-nldbl-errorfptr
>   
>   $(objpfx)tst-nldbl-warn.c: tst-ldbl-warn.c
>   	cp $< $@
> @@ -222,8 +223,11 @@ $(objpfx)tst-nldbl-warn.c: tst-ldbl-warn.c
>   $(objpfx)tst-nldbl-error.c: tst-ldbl-error.c
>   	cp $< $@
>   
> +$(objpfx)tst-nldbl-errorfptr.c: tst-ldbl-errorfptr.c
> +	cp $< $@
>   CFLAGS-tst-nldbl-warn.c += -mlong-double-64
>   CFLAGS-tst-nldbl-error.c += -mlong-double-64
> +CFLAGS-tst-nldbl-errorfptr.c += -mlong-double-64
>   endif
>   
>   ifeq ($(subdir), stdio-common)