From: Pedro Alves <palves@redhat.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 3/4] C++: handle glibc's ptrace(enum __ptrace_request, ...)
Date: Fri, 10 Jul 2015 21:52:00 -0000 [thread overview]
Message-ID: <1436565127-30293-4-git-send-email-palves@redhat.com> (raw)
In-Reply-To: <1436565127-30293-1-git-send-email-palves@redhat.com>
Building in C++ mode issues ~40 warnings like this:
../../src/gdb/linux-nat.c: In function âint linux_handle_extended_wait(lwp_info*, int, int)â:
../../src/gdb/linux-nat.c:2016:51: warning: invalid conversion from âintâ to â__ptrace_requestâ [-fpermissive]
ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
The issue is that in glibc, ptrace's first parameter is an enum.
That's not a problem if we pick the PTRACE_XXX requests from
sys/ptrace.h, as those will be values of the corresponding enum.
However, we have fallback definitions for PTRACE_XXX symbols when the
system headers miss them (such as PTRACE_GETEVENTMSG above), and those
are plain integer constants. E.g., nat/linux-ptrace.h:
#define PTRACE_GETEVENTMSG 0x4201
One idea would be to fix this by defining those fallbacks like:
-#define PTRACE_GETEVENTMSG 0x4201
+#define PTRACE_GETEVENTMSG ((enum __ptrace_request) 0x4201)
However, while glibc's ptrace uses enum __ptrace_request for first
parameter:
extern long int ptrace (enum __ptrace_request __request, ...) __THROW;
other libc's, like e.g., Android's bionic do not -- in that case, the
first parameter is int:
long ptrace(int request, pid_t pid, void * addr, void * data);
So the fix I came up is to make configure/ptrace.m4 also detect the
type of the ptrace's first parameter and defin PTRACE_TYPE_ARG1, as
already does the for parameters 3-4, and then simply wrap ptrace with
a macro that casts the first argument to the detected type. (I'm
leaving adding a nicer wrapper for when we drop building in C).
While this adds the wrapper, GNU/Linux files won't use it until the
next patch, which makes all native GNU/Linux files include
gdb_ptrace.h.
gdb/ChangeLog:
2015-07-10 Pedro Alves <palves@redhat.com>
* ptrace.m4 (ptrace tests): Test in C++ mode. Try with 'enum
__ptrace_request as first parameter type instead of int.
(PTRACE_TYPE_ARG1): Define.
* nat/gdb_ptrace.h [!PTRACE_TYPE_ARG5] (ptrace): Define as wrapper
that casts first argument to PTRACE_TYPE_ARG1.
* config.in: Regenerate.
* configure: Regenerate.
gdb/gdbserver/ChangeLog:
2015-07-10 Pedro Alves <palves@redhat.com>
* config.in: Regenerate.
* configure: Regenerate.
---
gdb/config.in | 3 ++
gdb/configure | 88 ++++++++++++++++++++++++++++++++++++++++++++-----
gdb/gdbserver/config.in | 3 ++
gdb/gdbserver/configure | 88 ++++++++++++++++++++++++++++++++++++++++++++-----
gdb/nat/gdb_ptrace.h | 4 +++
gdb/ptrace.m4 | 14 +++++++-
6 files changed, 181 insertions(+), 19 deletions(-)
diff --git a/gdb/config.in b/gdb/config.in
index 9ef53b3..d188088 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -653,6 +653,9 @@
assorted other type changes. */
#undef PROC_SERVICE_IS_OLD
+/* Define to the type of arg 1 for ptrace. */
+#undef PTRACE_TYPE_ARG1
+
/* Define to the type of arg 3 for ptrace. */
#undef PTRACE_TYPE_ARG3
diff --git a/gdb/configure b/gdb/configure
index 135c6ac..e1b778b 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -2398,6 +2398,51 @@ $as_echo "$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.
@@ -11929,6 +11974,7 @@ 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" | $as_tr_sh`
@@ -11944,6 +11990,17 @@ fi
done
+# Needs to be tested in C++ mode, to detect whether we need to cast
+# the first argument to enum __ptrace_request.
+if test "$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
@@ -11954,7 +12011,7 @@ gdb_ptrace_headers='
#endif
'
# There is no point in checking if we don't have a prototype.
-ac_fn_c_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
+ac_fn_cxx_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
"
if test "x$ac_cv_have_decl_ptrace" = x""yes; then :
ac_have_decl=1
@@ -11992,7 +12049,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='long'
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -12006,7 +12063,7 @@ extern int ptrace ();
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='int'
else
gdb_cv_func_ptrace_ret='long'
@@ -12040,8 +12097,8 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
- gdb_cv_func_ptrace_args='int,int,long,long'
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'
else
for gdb_arg1 in 'int' 'long'; do
@@ -12062,7 +12119,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;
fi
@@ -12082,7 +12139,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;
@@ -12107,6 +12164,11 @@ IFS=$ac_save_IFS
shift
cat >>confdefs.h <<_ACEOF
+#define PTRACE_TYPE_ARG1 $1
+_ACEOF
+
+
+cat >>confdefs.h <<_ACEOF
#define PTRACE_TYPE_ARG3 $3
_ACEOF
@@ -12123,6 +12185,15 @@ _ACEOF
fi
+if test "$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
@@ -13942,8 +14013,7 @@ $as_echo_n "checking compiler warning flags... " >&6; }
CFLAGS="$CFLAGS $w"
saved_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $w"
-
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
diff --git a/gdb/gdbserver/config.in b/gdb/gdbserver/config.in
index 6f2d0a1..e2566a9 100644
--- a/gdb/gdbserver/config.in
+++ b/gdb/gdbserver/config.in
@@ -310,6 +310,9 @@
/* Additional package description */
#undef PKGVERSION
+/* Define to the type of arg 1 for ptrace. */
+#undef PTRACE_TYPE_ARG1
+
/* Define to the type of arg 3 for ptrace. */
#undef PTRACE_TYPE_ARG3
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index fc6b966..409f42b 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -1878,6 +1878,51 @@ $as_echo "$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_check_type LINENO TYPE VAR INCLUDES
# -------------------------------------------
# Tests whether TYPE exists after having included INCLUDES, setting cache
@@ -5751,6 +5796,7 @@ 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" | $as_tr_sh`
@@ -5766,6 +5812,17 @@ fi
done
+# Needs to be tested in C++ mode, to detect whether we need to cast
+# the first argument to enum __ptrace_request.
+if test "$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
@@ -5776,7 +5833,7 @@ gdb_ptrace_headers='
#endif
'
# There is no point in checking if we don't have a prototype.
-ac_fn_c_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
+ac_fn_cxx_check_decl "$LINENO" "ptrace" "ac_cv_have_decl_ptrace" "$gdb_ptrace_headers
"
if test "x$ac_cv_have_decl_ptrace" = x""yes; then :
ac_have_decl=1
@@ -5814,7 +5871,7 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='long'
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -5828,7 +5885,7 @@ extern int ptrace ();
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_ret='int'
else
gdb_cv_func_ptrace_ret='long'
@@ -5862,8 +5919,8 @@ extern long ptrace (enum __ptrace_request, ...);
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
- gdb_cv_func_ptrace_args='int,int,long,long'
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ gdb_cv_func_ptrace_args='enum __ptrace_request,int,long,long'
else
for gdb_arg1 in 'int' 'long'; do
@@ -5884,7 +5941,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4";
break 4;
fi
@@ -5904,7 +5961,7 @@ extern $gdb_cv_func_ptrace_ret
return 0;
}
_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
+if ac_fn_cxx_try_compile "$LINENO"; then :
gdb_cv_func_ptrace_args="$gdb_arg1,$gdb_arg2,$gdb_arg3,$gdb_arg4,$gdb_arg5";
break 5;
@@ -5929,6 +5986,11 @@ IFS=$ac_save_IFS
shift
cat >>confdefs.h <<_ACEOF
+#define PTRACE_TYPE_ARG1 $1
+_ACEOF
+
+
+cat >>confdefs.h <<_ACEOF
#define PTRACE_TYPE_ARG3 $3
_ACEOF
@@ -5945,6 +6007,15 @@ _ACEOF
fi
+if test "$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=""
@@ -6087,8 +6158,7 @@ $as_echo_n "checking compiler warning flags... " >&6; }
CFLAGS="$CFLAGS $w"
saved_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $w"
-
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
diff --git a/gdb/nat/gdb_ptrace.h b/gdb/nat/gdb_ptrace.h
index a969681..0a98239 100644
--- a/gdb/nat/gdb_ptrace.h
+++ b/gdb/nat/gdb_ptrace.h
@@ -144,6 +144,10 @@ extern PTRACE_TYPE_RET ptrace();
# define ptrace(request, pid, addr, data) \
ptrace (request, pid, addr, data, 0)
# endif
+#else
+/* Wrapper that avoids adding a pointless cast to all callers. */
+# define ptrace(request, pid, addr, data) \
+ ptrace ((PTRACE_TYPE_ARG1) request, pid, addr, data)
#endif
#endif /* gdb_ptrace.h */
diff --git a/gdb/ptrace.m4 b/gdb/ptrace.m4
index e5fe7fa..f01c692 100644
--- a/gdb/ptrace.m4
+++ b/gdb/ptrace.m4
@@ -22,6 +22,12 @@ AC_DEFUN([GDB_AC_PTRACE],
AC_CHECK_HEADERS([sys/ptrace.h ptrace.h])
+# Needs to be tested in C++ mode, to detect whether we need to cast
+# the first argument to enum __ptrace_request.
+if test "$enable_build_with_cxx" = "yes"; then
+ AC_LANG_PUSH([C++])
+fi
+
gdb_ptrace_headers='
#include <sys/types.h>
#if HAVE_SYS_PTRACE_H
@@ -52,7 +58,7 @@ AC_DEFINE_UNQUOTED(PTRACE_TYPE_RET, $gdb_cv_func_ptrace_ret,
AC_CACHE_CHECK([types of arguments for ptrace], gdb_cv_func_ptrace_args, [
AC_TRY_COMPILE($gdb_ptrace_headers,
[extern long ptrace (enum __ptrace_request, ...);],
- [gdb_cv_func_ptrace_args='int,int,long,long'],[
+ [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
@@ -81,6 +87,8 @@ 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, $[4],
@@ -89,4 +97,8 @@ if test -n "$[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
])
--
1.9.3
next prev parent reply other threads:[~2015-07-10 21:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-10 21:52 [PATCH 0/4] C++: handle " Pedro Alves
2015-07-10 21:52 ` Pedro Alves [this message]
2015-07-10 21:52 ` [PATCH 2/4] Move gdb_ptrace.h to nat/ Pedro Alves
2015-07-10 21:52 ` [PATCH 1/4] make gdbserver use the same ptrace autoconf checks as gdb Pedro Alves
2015-07-10 22:00 ` [PATCH 4/4] Linux: sys/ptrace.h -> nat/gdb_ptrace.h everywhere Pedro Alves
2015-07-24 14:22 ` [PATCH 0/4] C++: handle ptrace(enum __ptrace_request, ...) Pedro Alves
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