x86: Add run-time tests for -mtls-dialect=gnu2

	* testsuite/config/default.exp (GNU2_CFLAGS): New.  Set
	to -mtls-dialect=gnu2 if target compiler supports it.
	* testsuite/ld-i386/tls.exp: Run -mtls-dialect=gnu2 tests.
	* testsuite/ld-x86-64/tls.exp: Likewise.
	* testsuite/ld-i386/tlsdesc1a.c: New file.
	* testsuite/ld-i386/tlsdesc1b.c: Likewise.
	* testsuite/ld-x86-64/tlsdesc1a.c: Likewise.
	* testsuite/ld-x86-64/tlsdesc1b.c: Likewise.

1 files changed, 37 insertions, 0 deletions

diff --git a/ld/testsuite/config/default.exp b/ld/testsuite/config/default.exp
index 899943c..f5cb188 100644
--- a/ld/testsuite/config/default.exp
+++ b/ld/testsuite/config/default.exp
@@ -328,3 +328,40 @@ if { ![info exists NOPIE_CFLAGS] || ![info exists NOPIE_LDFLAGS] } then {
 	set NOPIE_LDFLAGS ""
     }
 }
+
+# Set GNU2_CFLAGS to "-mtls-dialect=gnu2" if target compiler supports it.
+
+if { ![info exists GNU2_CFLAGS] } then {
+    if { [which $CC] != 0 } {
+	# Check if gcc supports -mtls-dialect=gnu2
+	set flags ""
+	if [board_info [target_info name] exists cflags] {
+	    append flags " [board_info [target_info name] cflags]"
+	}
+	if [board_info [target_info name] exists ldflags] {
+	    append flags " [board_info [target_info name] ldflags]"
+	}
+
+	set basename "tmpdir/gnu2[pid]"
+	set src ${basename}.c
+	set output ${basename}.o
+	set f [open $src "w"]
+	puts $f "__thread int yyy = 100;"
+	close $f
+	if [is_remote host] {
+	    set src [remote_download host $src]
+	}
+	set gnu2_available [run_host_cmd_yesno "$CC" "$flags -c -mtls-dialect=gnu2 $src -o $output"]
+	remote_file host delete $src
+	remote_file host delete $output
+	file delete $src
+
+	if { $gnu2_available == 1 } then {
+	    set GNU2_CFLAGS "-mtls-dialect=gnu2"
+	} else {
+	    set GNU2_CFLAGS ""
+	}
+    } else {
+	set GNU2_CFLAGS ""
+    }
+}