re PR driver/65444 (-z bndplt isn't passed to linker for -mmpx when building dynamic objects)

gcc/
	PR driver/65444
	* config/i386/linux-common.h (MPX_SPEC): New.
	(CHKP_SPEC): Add MPX_SPEC.
	* doc/invoke.texi (-fcheck-pointer-boudns): Document
	possible issues with '-z bndplt' support in linker.

libmpx/

	PR driver/65444
	* configure.ac: Add check for '-z bndplt' support
	by linker. Add link_mpx output variable.
	* libmpx.spec.in (link_mpx): New.
	* configure: Regenerate.

From-SVN: r221831

gcc/ChangeLog

+2015-04-02  Ilya Enkovich  <ilya.enkovich@intel.com>
+
+	PR driver/65444
+	* config/i386/linux-common.h (MPX_SPEC): New.
+	(CHKP_SPEC): Add MPX_SPEC.
+	* doc/invoke.texi (-fcheck-pointer-boudns): Document
+	possible issues with '-z bndplt' support in linker.
+
 2015-04-02  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/sync.md (UNSPEC_FILD_ATOMIC, UNSPEC_FIST_ATOMIC): New.

gcc/config/i386/linux-common.h

@@ -59,6 +59,11 @@ along with GCC; see the file COPYING3.  If not see
  %:include(libmpx.spec)%(link_libmpx)"
 #endif
 
+#ifndef MPX_SPEC
+#define MPX_SPEC "\
+ %{mmpx:%{fcheck-pointer-bounds:%{!static:%:include(libmpx.spec)%(link_mpx)}}}"
+#endif
+
 #ifndef LIBMPX_SPEC
 #if defined(HAVE_LD_STATIC_DYNAMIC)
 #define LIBMPX_SPEC "\
@@ -89,5 +94,5 @@ along with GCC; see the file COPYING3.  If not see
 
 #ifndef CHKP_SPEC
 #define CHKP_SPEC "\
-%{!nostdlib:%{!nodefaultlibs:" LIBMPX_SPEC LIBMPXWRAPPERS_SPEC "}}"
+%{!nostdlib:%{!nodefaultlibs:" LIBMPX_SPEC LIBMPXWRAPPERS_SPEC "}}" MPX_SPEC
 #endif

gcc/doc/invoke.texi

@@ -5857,7 +5857,16 @@ MPX-based instrumentation requires
 a runtime library to enable MPX in hardware and handle bounds
 violation signals.  By default when @option{-fcheck-pointer-bounds}
 and @option{-mmpx} options are used to link a program, the GCC driver
-links against the @file{libmpx} runtime library.  MPX-based instrumentation
+links against the @file{libmpx} runtime library and @file{libmpxwrappers}
+library.  It also passes '-z bndplt' to a linker in case it supports this
+option (which is checked on libmpx configuration).  Note that old versions
+of linker may ignore option.  Gold linker doesn't support '-z bndplt'
+option.  With no '-z bndplt' support in linker all calls to dynamic libraries
+lose passed bounds reducing overall protection level.  It's highly
+recommended to use linker with '-z bndplt' support.  In case such linker
+is not available it is adviced to always use @option{-static-libmpxwrappers}
+for better protection level or use @option{-static} to completely avoid
+external calls to dynamic libraries.  MPX-based instrumentation
 may be used for debugging and also may be included in production code
 to increase program security.  Depending on usage, you may
 have different requirements for the runtime library.  The current version

libmpx/ChangeLog

+2015-04-02  Ilya Enkovich  <ilya.enkovich@intel.com>
+
+	PR driver/65444
+	* configure.ac: Add check for '-z bndplt' support
+	by linker. Add link_mpx output variable.
+	* libmpx.spec.in (link_mpx): New.
+	* configure: Regenerate.
+
 2015-03-12  Ilya Enkovich  <ilya.enkovich@intel.com>
 
 	PR other/65384

libmpx/configure

@@ -670,6 +670,7 @@ am__isrc
 INSTALL_DATA
 INSTALL_SCRIPT
 INSTALL_PROGRAM
+link_mpx
 link_libmpx
 LIBMPX_SUPPORTED_FALSE
 LIBMPX_SUPPORTED_TRUE
@@ -2523,6 +2524,25 @@ fi
 
 
 link_libmpx="-lpthread"
+link_mpx=""
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ld accepts -z bndplt" >&5
+$as_echo_n "checking whether ld accepts -z bndplt... " >&6; }
+echo "int main() {};" > conftest.c
+if { ac_try='${CC} ${CFLAGS} -Wl,-z,bndplt -o conftest conftest.c 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+    link_mpx="$link_mpx -z bndplt"
+else
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
 
 
 am__api_version='1.11'
@@ -11648,7 +11668,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11651 "configure"
+#line 11671 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11754,7 +11774,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11757 "configure"
+#line 11777 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H

libmpx/configure.ac

@@ -40,7 +40,18 @@ AC_MSG_RESULT($LIBMPX_SUPPORTED)
 AM_CONDITIONAL(LIBMPX_SUPPORTED, [test "x$LIBMPX_SUPPORTED" = "xyes"])
 
 link_libmpx="-lpthread"
+link_mpx=""
+AC_MSG_CHECKING([whether ld accepts -z bndplt])
+echo "int main() {};" > conftest.c
+if AC_TRY_COMMAND([${CC} ${CFLAGS} -Wl,-z,bndplt -o conftest conftest.c 1>&AS_MESSAGE_LOG_FD])
+then
+    AC_MSG_RESULT([yes])
+    link_mpx="$link_mpx -z bndplt"
+else
+    AC_MSG_RESULT([no])
+fi
 AC_SUBST(link_libmpx)
+AC_SUBST(link_mpx)
 
 AM_INIT_AUTOMAKE(foreign no-dist no-dependencies)
 AM_ENABLE_MULTILIB(, ..)

libmpx/libmpx.spec.in

 # This spec file is read by gcc when linking.  It is used to specify the
-# standard libraries we need in order to link with libcilkrts.
+# standard libraries we need in order to link with libmpx.
 *link_libmpx: @link_libmpx@
+
+*link_mpx: @link_mpx@