libcpp: 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, 2 deletions

diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index a1b78bb..f6b7c01 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/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.
+
 2020-05-08  Nathan Sidwell  <nathan@acm.org>
 
 	Reimplement directives only processing, support raw literals.
diff --git a/libcpp/Makefile.in b/libcpp/Makefile.in
index 3d9ca0b..ebbca07 100644
--- a/libcpp/Makefile.in
+++ b/libcpp/Makefile.in
@@ -58,6 +58,7 @@ CXXDEPMODE = @CXXDEPMODE@
 DEPDIR = @DEPDIR@
 NOEXCEPTION_FLAGS = @noexception_flags@
 PICFLAG = @PICFLAG@
+CET_HOST_FLAGS = @CET_HOST_FLAGS@
 
 datarootdir = @datarootdir@
 datadir = @datadir@
@@ -73,9 +74,10 @@ depcomp = $(SHELL) $(srcdir)/../depcomp
 INCLUDES = -I$(srcdir) -I. -I$(srcdir)/../include @INCINTL@ \
 	-I$(srcdir)/include
 
-ALL_CFLAGS = $(CFLAGS) $(WARN_CFLAGS) $(INCLUDES) $(CPPFLAGS) $(PICFLAG)
+ALL_CFLAGS = $(CFLAGS) $(WARN_CFLAGS) $(INCLUDES) $(CPPFLAGS) $(PICFLAG) \
+	$(CET_HOST_FLAGS)
 ALL_CXXFLAGS = $(CXXFLAGS) $(WARN_CXXFLAGS) $(NOEXCEPTION_FLAGS) $(INCLUDES) \
-	$(CPPFLAGS) $(PICFLAG)
+	$(CPPFLAGS) $(PICFLAG) $(CET_HOST_FLAGS)
 
 # The name of the compiler to use.
 COMPILER = $(CXX)
diff --git a/libcpp/aclocal.m4 b/libcpp/aclocal.m4
index 46bb65a..70c3eff 100644
--- a/libcpp/aclocal.m4
+++ b/libcpp/aclocal.m4
@@ -13,8 +13,10 @@
 
 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/acx.m4])
+m4_include([../config/cet.m4])
 m4_include([../config/codeset.m4])
 m4_include([../config/depstand.m4])
+m4_include([../config/enable.m4])
 m4_include([../config/gettext-sister.m4])
 m4_include([../config/iconv.m4])
 m4_include([../config/lead-dot.m4])
diff --git a/libcpp/configure b/libcpp/configure
index 11da199..64bbf54 100755
--- a/libcpp/configure
+++ b/libcpp/configure
@@ -623,6 +623,7 @@ ac_includes_default="\
 #endif"
 
 ac_subst_vars='LTLIBOBJS
+CET_HOST_FLAGS
 PICFLAG
 MAINT
 USED_CATALOGS
@@ -735,6 +736,7 @@ enable_maintainer_mode
 enable_checking
 enable_canonical_system_headers
 enable_host_shared
+enable_cet
 enable_valgrind_annotations
 '
       ac_precious_vars='build_alias
@@ -1375,6 +1377,7 @@ Optional Features:
   --enable-canonical-system-headers
                           enable or disable system headers canonicalization
   --enable-host-shared    build host code as shared libraries
+  --enable-cet            enable Intel CET in host libraries [default=auto]
   --enable-valgrind-annotations
                           enable valgrind runtime interaction
 
@@ -7443,6 +7446,156 @@ 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
+
+
 # Check whether --enable-valgrind-annotations was given.
 if test "${enable_valgrind_annotations+set}" = set; then :
   enableval=$enable_valgrind_annotations;
diff --git a/libcpp/configure.ac b/libcpp/configure.ac
index 1779562..540efeb 100644
--- a/libcpp/configure.ac
+++ b/libcpp/configure.ac
@@ -206,6 +206,17 @@ 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)
+
 AC_ARG_ENABLE(valgrind-annotations,
 [AS_HELP_STRING([--enable-valgrind-annotations],
 		[enable valgrind runtime interaction])], [],