[patch+NEWS] Avoid false valgrind warnings on linux_ptrace_test_ret_to_nx

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Wed, 20 Feb 2013 16:06:21 +0100, Pedro Alves wrote:
> That reminds us that ideally new configury options are all
> advertised in NEWS.

Yes; forgot it.


> I assumed there'd be a reason for the more complete test,
> instead of a simpler and unconditional
> AC_CHECK_HEADERS(valgrind/valgrind.h) and then just
> 
> #ifdef RUNNING_ON_VALGRIND
>  if (RUNNING_ON_VALGRIND)
>     return;
> #endif
> 
> As in, you had found that older valgrind/valgrind.h's didn't
> have that RUNNING_ON_VALGRIND macro.

I haven't found such valgrind.  The reason is there could be a broken
valgrind.h include file installed.  As GDB built before not depending on such
file in the past and now it would break it would be a regression.

Or is somewhere a rule what should and what should not be tested by configure?


Thanks,
Jan


gdb/
2013-02-20  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* NEWS (--with-valgrind/--without-valgrind): New.
	* acinclude.m4: Include common/acinclude.m4.
	* common/acinclude.m4: New file.
	* common/linux-ptrace.c <HAVE_RUNNING_ON_VALGRIND>: Include
	valgrind/valgrind.h.
	(linux_ptrace_test_ret_to_nx) <HAVE_RUNNING_ON_VALGRIND>: Return.
	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Call GDB_AC_CHECK_VALGRIND.

gdb/gdbserver/
2013-02-20  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* acinclude.m4: Include ../common/acinclude.m4.
	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Call GDB_AC_CHECK_VALGRIND.

diff --git a/gdb/NEWS b/gdb/NEWS
index 0877aa2..3e11229 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -79,6 +79,15 @@ Lynx 178 PowerPC		powerpc-*-lynx*178
   by default.  The --enable-libmcheck/--disable-libmcheck configure
   options allow the user to override that default.
 
+--with-valgrind/--without-valgrind
+  Include special support when GDB itself runs under valgrind.  Without this
+  support valgrind will report a warning on linux_ptrace_test_ret_to_nx which
+  is not a bug in GDB.  Include file <valgrind/valgring.h> needs to be
+  installed for this support.  Include file is autodetected by default.  Using
+  --with-valgrind aborts the configure script if the valgrind include file is
+  not installed.  --without-valgrind omits the support in GDB even if the
+  include file is installed.
+
 * New commands (for set/show, see "New options" below)
 
 catch signal 
diff --git a/gdb/acinclude.m4 b/gdb/acinclude.m4
index 25caddd..12da851 100644
--- a/gdb/acinclude.m4
+++ b/gdb/acinclude.m4
@@ -49,6 +49,8 @@ sinclude([../config/codeset.m4])
 
 sinclude([../config/zlib.m4])
 
+sinclude([common/acinclude.m4])
+
 ## ----------------------------------------- ##
 ## ANSIfy the C compiler whenever possible.  ##
 ## From Franc,ois Pinard                     ##
diff --git a/gdb/common/acinclude.m4 b/gdb/common/acinclude.m4
new file mode 100644
index 0000000..fcb1c71
--- /dev/null
+++ b/gdb/common/acinclude.m4
@@ -0,0 +1,44 @@
+# Copyright 2013 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+dnl GDB_AC_CHECK_VALGRIND
+dnl Check for HAVE_RUNNING_ON_VALGRIND.
+dnl If such symbol is defined <valgrind/valgrind.h> is also available.
+AC_DEFUN([GDB_AC_CHECK_VALGRIND], [
+  AC_ARG_WITH([valgrind],
+    [AS_HELP_STRING([--without-valgrind],
+		  [do not include support for running-on-valgrind detection])],,
+    [with_valgrind=check])
+  if test "$with_valgrind" != no; then
+    AC_MSG_CHECKING([for RUNNING_ON_VALGRIND macro])
+    AC_CACHE_VAL(gdb_cv_check_running_on_valgrind, [
+      AC_LINK_IFELSE(
+	[AC_LANG_PROGRAM([[#include <valgrind/valgrind.h>]],
+	  [[return RUNNING_ON_VALGRIND;]])],
+	[gdb_cv_check_running_on_valgrind=yes],
+	[gdb_cv_check_running_on_valgrind=no])])
+    AC_MSG_RESULT($gdb_cv_check_running_on_valgrind)
+    if test "$gdb_cv_check_running_on_valgrind" = yes; then
+      with_valgrind=yes
+    elif test "$with_valgrind" = yes; then
+      AC_ERROR(
+	[--with-valgrind was requested but <valgrind/valgrind.h> was not found])
+    fi
+  fi
+  if test "$with_valgrind" = yes; then
+    AC_DEFINE(HAVE_RUNNING_ON_VALGRIND, 1,
+	    [Define if you have <valgrind/valgrind.h> and RUNNING_ON_VALGRIND.])
+  fi
+])
diff --git a/gdb/common/linux-ptrace.c b/gdb/common/linux-ptrace.c
index 886be80..97a314b 100644
--- a/gdb/common/linux-ptrace.c
+++ b/gdb/common/linux-ptrace.c
@@ -29,6 +29,10 @@
 #include "gdb_assert.h"
 #include "gdb_wait.h"
 
+#ifdef HAVE_RUNNING_ON_VALGRIND
+# include <valgrind/valgrind.h>
+#endif
+
 /* Find all possible reasons we could fail to attach PID and append these
    newline terminated reason strings to initialized BUFFER.  '\0' termination
    of BUFFER must be done by the caller.  */
@@ -76,6 +80,15 @@ linux_ptrace_test_ret_to_nx (void)
   long l;
   int status;
 
+  /* Below we'll mmap a non-executable page, which under Valgrind
+     results in annoying warnings such as
+     "Bad permissions for mapped region at address 0xfoobar".
+     Just skip the whole test if running under Valgrind.  */
+#ifdef HAVE_RUNNING_ON_VALGRIND
+  if (RUNNING_ON_VALGRIND)
+    return;
+#endif
+
   return_address = mmap (NULL, 2, PROT_READ | PROT_WRITE,
 			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   if (return_address == MAP_FAILED)
diff --git a/gdb/configure.ac b/gdb/configure.ac
index e501766..a7bac76 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1166,6 +1166,7 @@ AC_CHECK_FUNCS([canonicalize_file_name realpath getrusage getuid getgid \
 		ttrace wborder wresize setlocale iconvlist libiconvlist btowc \
 		setrlimit getrlimit posix_madvise waitpid lstat])
 AM_LANGINFO_CODESET
+GDB_AC_CHECK_VALGRIND
 
 # Check the return and argument types of ptrace.  No canned test for
 # this, so roll our own.
diff --git a/gdb/gdbserver/acinclude.m4 b/gdb/gdbserver/acinclude.m4
index 0e0bdc8..c5a93b7 100644
--- a/gdb/gdbserver/acinclude.m4
+++ b/gdb/gdbserver/acinclude.m4
@@ -12,6 +12,8 @@ sinclude(../../config/acx.m4)
 m4_include(../../config/depstand.m4)
 m4_include(../../config/lead-dot.m4)
 
+sinclude([../common/acinclude.m4])
+
 dnl Check for existence of a type $1 in libthread_db.h
 dnl Based on BFD_HAVE_SYS_PROCFS_TYPE in bfd/bfd.m4.
 
diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac
index 55fb461..d492e8b 100644
--- a/gdb/gdbserver/configure.ac
+++ b/gdb/gdbserver/configure.ac
@@ -71,6 +71,7 @@ AC_CHECK_HEADERS(sgtty.h termio.h termios.h sys/reg.h string.h dnl
 		 linux/perf_event.h)
 AC_CHECK_FUNCS(pread pwrite pread64 readlink)
 AC_REPLACE_FUNCS(vasprintf vsnprintf)
+GDB_AC_CHECK_VALGRIND
 
 # Check for UST
 ustlibs=""