binutils-gdb/gdb/ptrace.m4
Simon Marchi c884cc4619 gdb: remove HAVE_DECL_PTRACE
I stumbled on this snippet in nat/gdb_ptrace.h:

    /* Some systems, in particular DEC OSF/1, Digital Unix, Compaq Tru64
       or whatever it's called these days, don't provide a prototype for
       ptrace.  Provide one to silence compiler warnings.  */

    #ifndef HAVE_DECL_PTRACE
    extern PTRACE_TYPE_RET ptrace();
    #endif

I believe this is unnecessary today and should be removed.  First, the
comment only mentions OSes we don't support (and to be honest, I had
never even heard of).

But most importantly, in C++, a declaration with empty parenthesis
declares a function that accepts no arguments, unlike in C.  So if this
declaration was really used, GDB wouldn't build, since all ptrace call
sites pass some arguments.  Since we haven't heard anything about this
causing some build failures since we have transitioned to C++, I
conclude that it's not used.

This patch removes it as well as the corresponding configure check.

gdb/ChangeLog:

	* ptrace.m4: Don't check for ptrace declaration.
	* config.in: Re-generate.
	* configure: Re-generate.
	* nat/gdb_ptrace.h: Don't declare ptrace if HAVE_DECL_PTRACE is
	not defined.

gdbserver/ChangeLog:

	* config.in: Re-generate.
	* configure: Re-generate.

gdbsupport/ChangeLog:

	* config.in: Re-generate.
	* configure: Re-generate.
2020-03-20 11:57:49 -04:00

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dnl Copyright (C) 2012-2020 Free Software Foundation, Inc.
dnl
dnl This file is part of GDB.
dnl
dnl This program is free software; you can redistribute it and/or modify
dnl it under the terms of the GNU General Public License as published by
dnl the Free Software Foundation; either version 3 of the License, or
dnl (at your option) any later version.
dnl
dnl This program is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
dnl GNU General Public License for more details.
dnl
dnl You should have received a copy of the GNU General Public License
dnl along with this program. If not, see <http://www.gnu.org/licenses/>.
dnl Check the return and argument types of ptrace.
AC_DEFUN([GDB_AC_PTRACE],
[
AC_CHECK_HEADERS([sys/ptrace.h ptrace.h])
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
# include <sys/ptrace.h>
#endif
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
'
# Check return type. Varargs (used on GNU/Linux) conflict with the
# empty argument list, so check for that explicitly.
AC_CACHE_CHECK([return type of ptrace], gdb_cv_func_ptrace_ret,
AC_TRY_COMPILE($gdb_ptrace_headers,
[extern long ptrace (enum __ptrace_request, ...);],
gdb_cv_func_ptrace_ret='long',
AC_TRY_COMPILE($gdb_ptrace_headers,
[extern int ptrace ();],
gdb_cv_func_ptrace_ret='int',
gdb_cv_func_ptrace_ret='long')))
AC_DEFINE_UNQUOTED(PTRACE_TYPE_RET, $gdb_cv_func_ptrace_ret,
[Define as the return type of ptrace.])
# Check argument types.
AC_CACHE_CHECK([types of arguments for ptrace], gdb_cv_func_ptrace_args, [
AC_TRY_COMPILE($gdb_ptrace_headers,
[extern long ptrace (enum __ptrace_request, ...);],
[gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'],[
for gdb_arg1 in 'int' 'long'; do
for gdb_arg2 in 'pid_t' 'int' 'long'; do
for gdb_arg3 in 'int *' 'caddr_t' 'int' 'long' 'void *'; do
for gdb_arg4 in 'int' 'long' 'void *'; do
AC_TRY_COMPILE($gdb_ptrace_headers, [
extern $gdb_cv_func_ptrace_ret
ptrace ($gdb_arg1, $gdb_arg2, $gdb_arg3, $gdb_arg4);
], [gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;])
for gdb_arg5 in 'int *' 'int' 'long'; do
AC_TRY_COMPILE($gdb_ptrace_headers, [
extern $gdb_cv_func_ptrace_ret
ptrace ($gdb_arg1, $gdb_arg2, $gdb_arg3, $gdb_arg4, $gdb_arg5);
], [
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;])
done
done
done
done
done
# Provide a safe default value.
: ${gdb_cv_func_ptrace_args='int,int,long,long'}
])])
ac_save_IFS=$IFS; IFS=','
set dummy `echo "$gdb_cv_func_ptrace_args" | sed 's/\*/\*/g'`
IFS=$ac_save_IFS
shift
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG1, $[1],
[Define to the type of arg 1 for ptrace.])
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG3, $[3],
[Define to the type of arg 3 for ptrace.])
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG4, $[4],
[Define to the type of arg 4 for ptrace.])
if test -n "$[5]"; then
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG5, $[5],
[Define to the type of arg 5 for ptrace.])
fi
])