From e0da78a258a34c26488b7ae623f9ae8727c2b264 Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date: Mon, 14 Nov 2022 17:14:18 +0000
Subject: [PATCH 117/157] [Backport][SME] libgcc: aarch64: Configure check for
 .variant_pcs support

Reference: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=3ebb591c65b4fbe0cddd23ebc0ca2d9f7aef2cec

Ideally SME support routines in libgcc are marked as variant PCS symbols
so check if as supports the directive.

libgcc/ChangeLog:

	* config.in: Undef HAVE_AS_VARIANT_PCS.
	* configure: Regenerate.
	* configure.ac: Check for .variant_pcs.
---
 libgcc/config.in    |  3 +++
 libgcc/configure    | 39 +++++++++++++++++++++++++++++++++++++++
 libgcc/configure.ac | 17 +++++++++++++++++
 3 files changed, 59 insertions(+)

diff --git a/libgcc/config.in b/libgcc/config.in
index f93c64a00..5dd96cdf6 100644
--- a/libgcc/config.in
+++ b/libgcc/config.in
@@ -13,6 +13,9 @@
 /* Define to 1 if the assembler supports LSE. */
 #undef HAVE_AS_LSE
 
+/* Define to 1 if the assembler supports .variant_pcs. */
+#undef HAVE_AS_VARIANT_PCS
+
 /* Define to 1 if the target assembler supports thread-local storage. */
 #undef HAVE_CC_TLS
 
diff --git a/libgcc/configure b/libgcc/configure
index 1f9b2ac57..afe02b303 100755
--- a/libgcc/configure
+++ b/libgcc/configure
@@ -5619,6 +5619,45 @@ $as_echo "#define HAVE_AS_LSE 1" >>confdefs.h
   ;;
 esac
 
+
+
+case "${target}" in
+aarch64*-*-*)
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if as supports .variant_pcs" >&5
+$as_echo_n "checking if as supports .variant_pcs... " >&6; }
+if ${libgcc_cv_as_variant_pcs+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+asm (".variant_pcs foobar");
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  libgcc_cv_as_variant_pcs=yes
+else
+  libgcc_cv_as_variant_pcs=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgcc_cv_as_variant_pcs" >&5
+$as_echo "$libgcc_cv_as_variant_pcs" >&6; }
+  if test x$libgcc_cv_as_variant_pcs = xyes; then
+
+$as_echo "#define HAVE_AS_VARIANT_PCS 1" >>confdefs.h
+
+  fi
+  ;;
+esac
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for init priority support" >&5
 $as_echo_n "checking for init priority support... " >&6; }
 if ${libgcc_cv_init_priority+:} false; then :
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index 2fc9d5d7c..abc398c91 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -648,6 +648,23 @@ changequote([,])dnl
 esac])
 LIBGCC_CHECK_AS_LSE
 
+dnl Check if as supports .variant_pcs.
+AC_DEFUN([LIBGCC_CHECK_AS_VARIANT_PCS], [
+case "${target}" in
+aarch64*-*-*)
+  AC_CACHE_CHECK([if as supports .variant_pcs], libgcc_cv_as_variant_pcs, [
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,
+      [[asm (".variant_pcs foobar");]])],
+      [libgcc_cv_as_variant_pcs=yes], [libgcc_cv_as_variant_pcs=no])
+  ])
+  if test x$libgcc_cv_as_variant_pcs = xyes; then
+    AC_DEFINE(HAVE_AS_VARIANT_PCS, 1,
+	      [Define to 1 if the assembler supports .variant_pcs.])
+  fi
+  ;;
+esac])
+LIBGCC_CHECK_AS_VARIANT_PCS
+
 dnl Check if as supports RTM instructions.
 AC_CACHE_CHECK(for init priority support, libgcc_cv_init_priority, [
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,
-- 
2.33.0