Re: [PATCH v4 v4] Added Redirects to longdouble error functions [BZ #29033]

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 27/03/23 03:27, Sachin Monga via Libc-alpha 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>

This patch triggered a regression on i668 patchwork buildbot [1]

[1] https://www.delorie.com/trybots/32bit/18447/

> ---
>  misc/Makefile                               |   2 +-
>  misc/bits/error-ldbl.h                      |  53 ++++++++-
>  misc/sys/cdefs.h                            |   3 +-
>  misc/tst-ldbl-errorfptr.c                   | 117 ++++++++++++++++++++
>  sysdeps/ieee754/ldbl-128ibm-compat/Makefile |   2 +
>  sysdeps/ieee754/ldbl-opt/Makefile           |   4 +
>  6 files changed, 177 insertions(+), 4 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..638e030c96 100644
> --- a/misc/bits/error-ldbl.h
> +++ b/misc/bits/error-ldbl.h
> @@ -20,5 +20,54 @@
>  # error "Never include <bits/error-ldbl.h> directly; use <error.h> instead."
>  #endif
>  
> -__LDBL_REDIR_DECL (error)
> -__LDBL_REDIR_DECL (error_at_line)
> +
> +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 ());
> +}
> 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..96b30cd83b
> --- /dev/null
> +++ b/misc/tst-ldbl-errorfptr.c
> @@ -0,0 +1,117 @@
> +/* Test for the long double redirections in error* functions
> +   when they are returned as function pointer BZ #29033.
> +   Copyright (C) 2018-2023 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 <support/capture_subprocess.h>
> +#include <support/check.h>
> +
> +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(int ver) {
> +  if(ver)
> +    return &__error_alias;
> +
> +  return &__error_noreturn;
> +}
> +
> +error_at_line_func_t
> +__attribute__((noinline))
> +get_error_at_line_func(int ver) {
> +  if(ver)
> +    return &__error_at_line_alias;
> +
> +  return &__error_at_line_noreturn;
> +}
> +
> +static int
> +do_test (int argc, char *argv[])
> +{
> +  /* Trim needle from testcase name */
> +  const char *needle = "tst-";
> +  char *message;
> +  message = strstr (argv[0], needle);
> +  if (message == NULL)
> +    FAIL_EXIT1 ("test case error - needle not found");
> +  message += strlen (needle);
> +
> +  /* Create buffer with max length symbol + 1 */
> +  char exp[15];
> +  char exp_at_line[23];
> +  /* Prepare the symbol names */
> +  if(!strncmp (message, "ldbl", strlen("ldbl")) ||
> +		  !strncmp (message, "ieee128", strlen("ieee128")))
> +    {
> +      strcpy(exp, "__errorieee128");
> +      strcpy (exp_at_line, "__error_at_lineieee128");
> +    }
> +  else if(!strncmp (message, "nldbl", strlen("nldbl")))
> +    {
> +      strcpy (exp, "__nldbl_error");
> +      strcpy (exp_at_line, "__nldbl_error_at_line");
> +    }
> +  else
> +    FAIL_EXIT1 ("test case error");
> +
> +  /* Map the function pointers to appropriate redirected symbols */
> +  error_func_t fp;
> +  fp = get_error_func(0);
> +  if (fp != dlsym(RTLD_DEFAULT, exp))
> +    {
> +      printf("\nFAIL fp=%p exp=%p\n",fp,exp);
> +      return 1;
> +    }
> +
> +  fp = get_error_func(1);
> +  if (fp != dlsym(RTLD_DEFAULT, exp))
> +    {
> +      printf("\nFAIL ver1 fp=%p exp=%p\n",fp,exp);
> +      return 1;
> +    }
> +
> +  error_at_line_func_t fpat;
> +  fpat = get_error_at_line_func(0);
> +  if (fpat != dlsym(RTLD_DEFAULT, exp_at_line))
> +    {
> +      printf("\nFAIL fp=%p exp_at_line=%p\n",fp,exp_at_line);
> +      return 1;
> +    }
> +
> +  fpat = get_error_at_line_func(1);
> +  if (fpat != dlsym(RTLD_DEFAULT, exp_at_line))
> +    {
> +      printf("\nFAIL ver1 fp=%p exp_at_line=%p\n",fp,exp_at_line);
> +      return 1;
> +    }
> +
> +  return 0;
> +}
> +
> +#define TEST_FUNCTION_ARGV do_test
> +#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)