libdecnumber: Enable Intel CET on Intel CET enabled host for jit

Since on Intel CET enabled host, dlopen in Intel CET enabled applications
fails on shared libraries which aren't Intel CET enabled, compile with
-fcf-protection on Intel CET enabled host when jit is enabled to enable
Intel CET on libgccjit.

	* Makefile.in (CET_HOST_FLAGS): New.
	(COMPILER): Add $(CET_HOST_FLAGS).
	* configure.ac: Add GCC_CET_HOST_FLAGS(CET_HOST_FLAGS) and
	AC_SUBST(CET_HOST_FLAGS).  Clear CET_HOST_FLAGS if jit isn't
	enabled.
	* aclocal.m4: Regenerated.
	* configure: Likewise.

5 files changed, 180 insertions, 1 deletions

diff --git a/libdecnumber/ChangeLog b/libdecnumber/ChangeLog
index 9fe1464c764..6bdc7574c20 100644
--- a/libdecnumber/ChangeLog
+++ b/libdecnumber/ChangeLog
@@ -1,3 +1,13 @@
+2020-05-12  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* Makefile.in (CET_HOST_FLAGS): New.
+	(COMPILER): Add $(CET_HOST_FLAGS).
+	* configure.ac: Add GCC_CET_HOST_FLAGS(CET_HOST_FLAGS) and
+	AC_SUBST(CET_HOST_FLAGS).  Clear CET_HOST_FLAGS if jit isn't
+	enabled.
+	* aclocal.m4: Regenerated.
+	* configure: Likewise.
+
 2020-01-01  Jakub Jelinek  <jakub@redhat.com>
 
 	Update copyright years.
diff --git a/libdecnumber/Makefile.in b/libdecnumber/Makefile.in
index a97aa0b96b4..9260b4849c8 100644
--- a/libdecnumber/Makefile.in
+++ b/libdecnumber/Makefile.in
@@ -41,6 +41,7 @@ LDFLAGS = @LDFLAGS@
 LIBICONV = @LIBICONV@
 PACKAGE = @PACKAGE@
 PICFLAG = @PICFLAG@
+CET_HOST_FLAGS = @CET_HOST_FLAGS@
 RANLIB = @RANLIB@
 SHELL = @SHELL@
 objext = @OBJEXT@
@@ -60,7 +61,7 @@ enable_decimal_float= @enable_decimal_float@
 INCLUDES = -I$(srcdir) -I.
 
 ALL_CFLAGS = $(CFLAGS) $(WARN_CFLAGS) $(NOLTO_FLAGS) $(INCLUDES) $(CPPFLAGS) \
-	     $(PICFLAG)
+	     $(PICFLAG) $(CET_HOST_FLAGS)
 
 bid_OBJS = bid2dpd_dpd2bid.$(objext) host-ieee32.$(objext) \
 	host-ieee64.$(objext) host-ieee128.$(objext)
diff --git a/libdecnumber/aclocal.m4 b/libdecnumber/aclocal.m4
index 749c90355c8..fe9f8b4f979 100644
--- a/libdecnumber/aclocal.m4
+++ b/libdecnumber/aclocal.m4
@@ -12,6 +12,8 @@
 # PARTICULAR PURPOSE.
 
 m4_ifndef([AC_CONFIG_MACRO_DIRS], [m4_defun([_AM_CONFIG_MACRO_DIRS], [])m4_defun([AC_CONFIG_MACRO_DIRS], [_AM_CONFIG_MACRO_DIRS($@)])])
+m4_include([../config/cet.m4])
 m4_include([../config/dfp.m4])
+m4_include([../config/enable.m4])
 m4_include([../config/stdint.m4])
 m4_include([../config/warnings.m4])
diff --git a/libdecnumber/configure b/libdecnumber/configure
index 14c103a0718..b4542781457 100755
--- a/libdecnumber/configure
+++ b/libdecnumber/configure
@@ -624,6 +624,7 @@ ac_includes_default="\
 
 ac_subst_vars='LTLIBOBJS
 LIBOBJS
+CET_HOST_FLAGS
 PICFLAG
 ADDITIONAL_OBJS
 enable_decimal_float
@@ -704,6 +705,7 @@ enable_werror_always
 enable_maintainer_mode
 enable_decimal_float
 enable_host_shared
+enable_cet
 '
       ac_precious_vars='build_alias
 host_alias
@@ -1335,6 +1337,7 @@ Optional Features:
 			or 'dpd' choses which decimal floating point format
 			to use
   --enable-host-shared    build host code as shared libraries
+  --enable-cet            enable Intel CET in host libraries [default=auto]
 
 Some influential environment variables:
   CC          C compiler command
@@ -5050,6 +5053,157 @@ fi
 
 
 
+# Enable Intel CET on Intel CET enabled host if jit is enabled.
+ # Check whether --enable-cet was given.
+if test "${enable_cet+set}" = set; then :
+  enableval=$enable_cet;
+      case "$enableval" in
+       yes|no|auto) ;;
+       *) as_fn_error $? "Unknown argument to enable/disable cet" "$LINENO" 5 ;;
+                          esac
+
+else
+  enable_cet=auto
+fi
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for CET support" >&5
+$as_echo_n "checking for CET support... " >&6; }
+
+case "$host" in
+  i[34567]86-*-linux* | x86_64-*-linux*)
+    may_have_cet=yes
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS -fcf-protection"
+    case "$enable_cet" in
+      auto)
+	# Check if target supports multi-byte NOPs
+	# and if assembler supports CET insn.
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+#if !defined(__SSE2__)
+#error target does not support multi-byte NOPs
+#else
+asm ("setssbsy");
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  enable_cet=yes
+else
+  enable_cet=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	;;
+      yes)
+	# Check if assembler supports CET.
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+asm ("setssbsy");
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+else
+  as_fn_error $? "assembler with CET support is required for --enable-cet" "$LINENO" 5
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	;;
+    esac
+    CFLAGS="$save_CFLAGS"
+    ;;
+  *)
+    may_have_cet=no
+    enable_cet=no
+    ;;
+esac
+
+if test x$may_have_cet = xyes; then
+  save_LDFLAGS="$LDFLAGS"
+  LDFLAGS="$LDFLAGS -Wl,-z,ibt,-z,shstk"
+  if test "$cross_compiling" = yes; then :
+  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot run test program while cross compiling
+See \`config.log' for more details" "$LINENO" 5; }
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+static void
+foo (void)
+{
+}
+
+static void
+__attribute__ ((noinline, noclone))
+xxx (void (*f) (void))
+{
+  f ();
+}
+
+static void
+__attribute__ ((noinline, noclone))
+bar (void)
+{
+  xxx (foo);
+}
+
+int
+main ()
+{
+  bar ();
+  return 0;
+}
+
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  have_cet=no
+else
+  have_cet=yes
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+  LDFLAGS="$save_LDFLAGS"
+  if test x$enable_cet = xno -a x$have_cet = xyes; then
+    as_fn_error $? "Intel CET must be enabled on Intel CET enabled host" "$LINENO" 5
+  fi
+fi
+if test x$enable_cet = xyes; then
+  CET_HOST_FLAGS="-fcf-protection"
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+
+case x$enable_languages in
+*jit*)
+  ;;
+*)
+  CET_HOST_FLAGS=
+  ;;
+esac
+
+
+
 # Output.
 
 ac_config_headers="$ac_config_headers config.h:config.in"
diff --git a/libdecnumber/configure.ac b/libdecnumber/configure.ac
index 45449cd7144..de7e0088ceb 100644
--- a/libdecnumber/configure.ac
+++ b/libdecnumber/configure.ac
@@ -103,6 +103,18 @@ AC_ARG_ENABLE(host-shared,
 [PICFLAG=-fPIC], [PICFLAG=])
 AC_SUBST(PICFLAG)
 
+# Enable Intel CET on Intel CET enabled host if jit is enabled.
+GCC_CET_HOST_FLAGS(CET_HOST_FLAGS)
+case x$enable_languages in
+*jit*)
+  ;;
+*)
+  CET_HOST_FLAGS=
+  ;;
+esac
+AC_SUBST(CET_HOST_FLAGS)
+
+
 # Output.
 
 AC_CONFIG_HEADERS(config.h:config.in, [echo timestamp > stamp-h1])