Set PLT_CFLAGS to "-fplt" if supported

GCC 6 supports -fno-plt.  But some linker tests expect PLT.  This patch
defines PLT_CFLAGS to "-fplt" if target compiler supports it.

	* config/default.exp (PLT_CFLAGS): New.

2 files changed, 39 insertions, 0 deletions

diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index db1302f..a81149c 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-07-27  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* config/default.exp (PLT_CFLAGS): New.
+
 2015-07-27  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
 	PR ld/18705
diff --git a/ld/testsuite/config/default.exp b/ld/testsuite/config/default.exp
index e25189b..5acc963 100644
--- a/ld/testsuite/config/default.exp
+++ b/ld/testsuite/config/default.exp
@@ -278,3 +278,38 @@ if ![info exists LD] then {
 if ![info exists LDFLAGS] then {
     set LDFLAGS {}
 }
+
+# Set PLT_CFLAGS to "-fplt" if target compiler supports it.
+
+if { ![info exists PLT_CFLAGS] } then {
+    if { [which $CC] != 0 } {
+	# Check if gcc supports -fplt
+	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/plt[pid]"
+	set src ${basename}.c
+	set output ${basename}.o
+	set f [open $src "w"]
+	puts $f ""
+	close $f
+	remote_download host $src
+	set plt_available [run_host_cmd_yesno "$CC" "$flags -c -fplt $src -o $output"]
+	remote_file host delete $src
+	remote_file host delete $output
+	file delete $src
+
+	if { $plt_available == 1 } then {
+	    set PLT_CFLAGS "-fplt"
+	} else {
+	    set PLT_CFLAGS ""
+	}
+    } else {
+	set PLT_CFLAGS ""
+    }
+}