https://gcc.gnu.org/94998
https://bugs.gentoo.org/729074

From 2c7ae01349f779f1d4e66d8831052ee59f9c948b Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 12 May 2020 10:39:42 -0700
Subject: [PATCH] Enable CET in cross compiler if possible

Don't perform CET run-time check for host when cross compiling.  Instead,
enable CET in cross compiler if possible so that it will run on both CET
and non-CET hosts.

config/

	PR bootstrap/94998
	* cet.m4 (GCC_CET_HOST_FLAGS): Enable CET in cross compiler if
	possible.

libiberty/

	PR bootstrap/94998
	* configure: Regenerated.

lto-plugin/

	PR bootstrap/94998
	* configure: Regenerated.

(cherry picked from commit d17cdc17c90ce77cb90c569322c1f241d3530cec)
---
 config/cet.m4        | 18 ++++++++++++------
 libiberty/configure  | 12 +++++++++---
 lto-plugin/configure | 16 +++++++++++-----
 3 files changed, 32 insertions(+), 14 deletions(-)

--- a/config/cet.m4
+++ b/config/cet.m4
@@ -111,7 +111,8 @@ if test x$may_have_cet = xyes; then
 fi
 
 if test x$may_have_cet = xyes; then
-  AC_TRY_RUN([
+  if test x$cross_compiling = xno; then
+    AC_TRY_RUN([
 static void
 foo (void)
 {
@@ -137,12 +138,17 @@ main ()
   bar ();
   return 0;
 }
-  ],
-  [have_cet=no],
-  [have_cet=yes])
-  if test x$enable_cet = xno -a x$have_cet = xyes; then
-    AC_MSG_ERROR([Intel CET must be enabled on Intel CET enabled host])
+    ],
+    [have_cet=no],
+    [have_cet=yes])
+    if test x$enable_cet = xno -a x$have_cet = xyes; then
+      AC_MSG_ERROR([Intel CET must be enabled on Intel CET enabled host])
+    fi
   fi
+else
+  # Enable CET in cross compiler if possible so that it will run on both
+  # CET and non-CET hosts.
+  have_cet=yes
 fi
 if test x$enable_cet = xyes; then
   $1="-fcf-protection"
--- a/libiberty/configure
+++ b/libiberty/configure
@@ -5375,7 +5375,8 @@ rm -f core conftest.err conftest.$ac_objext \
 fi
 
 if test x$may_have_cet = xyes; then
-  if test "$cross_compiling" = yes; then :
+  if test x$cross_compiling = xno; then
+    if test "$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 $? "cannot run test program while cross compiling
@@ -5420,9 +5421,14 @@ rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
   conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
 
-  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
+    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
+else
+  # Enable CET in cross compiler if possible so that it will run on both
+  # CET and non-CET hosts.
+  have_cet=yes
 fi
 if test x$enable_cet = xyes; then
   CET_HOST_FLAGS="-fcf-protection"
--- a/lto-plugin/configure
+++ b/lto-plugin/configure
@@ -5768,7 +5768,8 @@ rm -f core conftest.err conftest.$ac_objext \
 fi
 
 if test x$may_have_cet = xyes; then
-  if test "$cross_compiling" = yes; then :
+  if test x$cross_compiling = xno; then
+    if test "$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 $? "cannot run test program while cross compiling
@@ -5813,9 +5814,14 @@ rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
   conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
 
-  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
+    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
+else
+  # Enable CET in cross compiler if possible so that it will run on both
+  # CET and non-CET hosts.
+  have_cet=yes
 fi
 if test x$enable_cet = xyes; then
   CET_HOST_FLAGS="-fcf-protection"
@@ -11941,7 +11947,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11944 "configure"
+#line 11950 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12047,7 +12053,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 12050 "configure"
+#line 12056 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
-- 
2.27.0