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Fix PR gdb/19250: ptrace prototype is not detected properly in C++ mode

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The ptrace args/return types detection doesn't work properly in C++
mode, on non-GNU/Linux hosts.  For example, on gcc70 (NetBSD 5.1),
where the prototype is:

 int ptrace(int, __pid_t, void*, int);

configure misdetects it as:

 $ grep PTRACE_TYPE config.h
 #define PTRACE_TYPE_ARG1 int
 #define PTRACE_TYPE_ARG3 int *
 #define PTRACE_TYPE_ARG4 int
 /* #undef PTRACE_TYPE_ARG5 */
 #define PTRACE_TYPE_RET int

resulting in:

 ../../src/gdb/amd64bsd-nat.c: In function 'void amd64bsd_fetch_inferior_registers(target_ops*, regcache*, int)':
 ../../src/gdb/amd64bsd-nat.c:56: warning: dereferencing type-punned pointer will break strict-aliasing rules
 ../../src/gdb/amd64bsd-nat.c: In function 'void amd64bsd_store_inferior_registers(target_ops*, regcache*, int)':
 ../../src/gdb/amd64bsd-nat.c:104: warning: dereferencing type-punned pointer will break strict-aliasing rules
 ../../src/gdb/amd64bsd-nat.c:110: warning: dereferencing type-punned pointer will break strict-aliasing rules

We could address this [1], however despite ptrace.m4's claim:

 # Needs to be tested in C++ mode, to detect whether we need to cast
 # the first argument to enum __ptrace_request.

it appears that there's actually no need to test in C++ mode.  Always
running the ptrace tests in C mode works just the same on GNU/Linux.

I remember experimenting with several different ways to handle the
original issue back then, and maybe that was needed in some other
attempt and then I didn't realize it ended up not really necessary.

Confirmed that this fixes the NetBSD 5.1 C++ build, and confirmed that
C and C++ builds on Fedora 23 are unaffected.

[1] - https://sourceware.org/ml/gdb-patches/2016-04/msg00374.html

gdb/ChangeLog:
2016-04-18  Pedro Alves  <palves@redhat.com>

	* ptrace.m4 (GDB_AC_PTRACE): Don't run tests in C++ mode.
	* configure: Regenerate.

gdb/gdbserver/ChangeLog:
2016-04-18  Pedro Alves  <palves@redhat.com>

	* configure: Regenerate.
This commit is contained in:
Pedro Alves 2016-04-18 17:42:50 +01:00
parent a22df60ad2
commit 9b30624b65
5 changed files with 23 additions and 154 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gdb/ChangeLog
View File

@ -1,3 +1,8 @@
2016-04-18 Pedro Alves <palves@redhat.com>
* ptrace.m4 (GDB_AC_PTRACE): Don't run tests in C++ mode.
* configure: Regenerate.
2016-04-18 Martin Galvan <martin.galvan@tallertechnologies.com>
* valops.c (value_addr): For C++ references, set the copied value's

79
gdb/configure vendored
View File

@ -2401,51 +2401,6 @@ $as_echo "$ac_res" >&6; }
eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
} # ac_fn_c_check_member
# ac_fn_cxx_check_decl LINENO SYMBOL VAR
# --------------------------------------
# Tests whether SYMBOL is declared, setting cache variable VAR accordingly.
ac_fn_cxx_check_decl ()
{
as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
as_decl_name=`echo $2|sed 's/ *(.*//'`
as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
$as_echo_n "(cached) " >&6
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
#ifndef $as_decl_name
#ifdef __cplusplus
(void) $as_decl_use;
#else
(void) $as_decl_name;
#endif
#endif
;
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
eval "$3=yes"
else
eval "$3=no"
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
eval ac_res=\$$3
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
} # ac_fn_cxx_check_decl
cat >config.log <<_ACEOF
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.
@ -12351,7 +12306,6 @@ fi
# Check the return and argument types of ptrace.
for ac_header in sys/ptrace.h ptrace.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
@ -12367,17 +12321,6 @@ fi
done
# Needs to be tested in C++ mode, to detect whether we need to cast
# the first argument to enum __ptrace_request.
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=cpp
ac_cpp='$CXXCPP $CPPFLAGS'
ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
fi
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@ -12388,7 +12331,7 @@ gdb_ptrace_headers='
#endif
'
# There is no point in checking if we don't have a prototype.
ac_fn_cxx_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
ac_fn_c_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
"
if test "x$ac_cv_have_decl_ptrace" = x""yes; then :
ac_have_decl=1
@ -12426,7 +12369,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='long'
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@ -12440,7 +12383,7 @@ extern int ptrace ();
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='int'
else
gdb_cv_func_ptrace_ret='long'
@ -12474,7 +12417,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'
else
@ -12496,7 +12439,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;
fi
@ -12516,7 +12459,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;
@ -12562,15 +12505,6 @@ _ACEOF
fi
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_c_compiler_gnu
fi
if test "$cross_compiling" = no; then
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether setpgrp takes no argument" >&5
@ -14265,6 +14199,7 @@ _ACEOF
# Check whether --enable-werror was given.
if test "${enable_werror+set}" = set; then :
enableval=$enable_werror; case "${enableval}" in

4
gdb/gdbserver/ChangeLog
View File

@ -1,3 +1,7 @@
2016-04-18 Pedro Alves <palves@redhat.com>
* configure: Regenerate.
2016-04-13 Antoine Tremblay <antoine.tremblay@ericsson.com>
* linux-aarch64-low.c (aarch64_emit_add): Switch x1 and x0.

79
gdb/gdbserver/configure vendored
View File

@ -1939,51 +1939,6 @@ $as_echo "$ac_res" >&6; }
} # ac_fn_c_check_decl
# ac_fn_cxx_check_decl LINENO SYMBOL VAR
# --------------------------------------
# Tests whether SYMBOL is declared, setting cache variable VAR accordingly.
ac_fn_cxx_check_decl ()
{
as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
as_decl_name=`echo $2|sed 's/ *(.*//'`
as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
$as_echo_n "checking whether $as_decl_name is declared... " >&6; }
if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
$as_echo_n "(cached) " >&6
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
$4
int
main ()
{
#ifndef $as_decl_name
#ifdef __cplusplus
(void) $as_decl_use;
#else
(void) $as_decl_name;
#endif
#endif
;
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
eval "$3=yes"
else
eval "$3=no"
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
fi
eval ac_res=\$$3
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
} # ac_fn_cxx_check_decl
# ac_fn_c_compute_int LINENO EXPR VAR INCLUDES
# --------------------------------------------
# Tries to find the compile-time value of EXPR in a program that includes
@ -6030,7 +5985,6 @@ fi
# Check the return and argument types of ptrace.
for ac_header in sys/ptrace.h ptrace.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
@ -6046,17 +6000,6 @@ fi
done
# Needs to be tested in C++ mode, to detect whether we need to cast
# the first argument to enum __ptrace_request.
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=cpp
ac_cpp='$CXXCPP $CPPFLAGS'
ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
fi
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@ -6067,7 +6010,7 @@ gdb_ptrace_headers='
#endif
'
# There is no point in checking if we don't have a prototype.
ac_fn_cxx_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
ac_fn_c_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
"
if test "x$ac_cv_have_decl_ptrace" = x""yes; then :
ac_have_decl=1
@ -6105,7 +6048,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='long'
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@ -6119,7 +6062,7 @@ extern int ptrace ();
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='int'
else
gdb_cv_func_ptrace_ret='long'
@ -6153,7 +6096,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'
else
@ -6175,7 +6118,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;
fi
@ -6195,7 +6138,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
if ac_fn_c_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;
@ -6241,15 +6184,6 @@ _ACEOF
fi
if test "$enable_build_with_cxx" = "yes"; then
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_c_compiler_gnu
fi
# Check for UST
ustlibs=""
@ -6332,6 +6266,7 @@ fi
# Check whether --enable-werror was given.
if test "${enable_werror+set}" = set; then :
enableval=$enable_werror; case "${enableval}" in

10
gdb/ptrace.m4
View File

@ -22,12 +22,6 @@ AC_DEFUN([GDB_AC_PTRACE],
AC_CHECK_HEADERS([sys/ptrace.h ptrace.h])
# Needs to be tested in C++ mode, to detect whether we need to cast
# the first argument to enum __ptrace_request.
if test "$enable_build_with_cxx" = "yes"; then
AC_LANG_PUSH([C++])
fi
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@ -97,8 +91,4 @@ if test -n "$[5]"; then
AC_DEFINE_UNQUOTED(PTRACE_TYPE_ARG5, $[5],
[Define to the type of arg 5 for ptrace.])
fi
if test "$enable_build_with_cxx" = "yes"; then
AC_LANG_POP([C++])
fi
])