Add and use check_lto_shared_available

2014-01-09  Vidya Praveen  <vidyapraveen@arm.com>

	* lib/ld-lib.exp (check_lto_shared_available): New check.
	* ld-plugin/lto.exp: Use check_lto_shared_available.

ld/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2014-01-09  Vidya Praveen  <vidyapraveen@arm.com>
+
+	* lib/ld-lib.exp (check_lto_shared_available): New check.
+	* ld-plugin/lto.exp: Use check_lto_shared_available.
+
 2014-01-08  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/14207

ld/testsuite/ld-plugin/lto.exp

@@ -300,8 +300,7 @@ set lto_run_elf_tests {
 run_cc_link_tests $lto_link_tests
 
 # Restrict these to ELF targets that support shared libs and PIC.
-if { [is_elf_format]
-     && [run_host_cmd_yesno $CC "-shared -fPIC $srcdir/$subdir/dummy.c -o tmpdir/t.so"] } {
+if { [is_elf_format] && [check_lto_shared_available] } {
     run_cc_link_tests $lto_link_elf_tests
     set testname "PR ld/15146 (2)"
     set exec_output [run_host_cmd "$CC" "$gcc_gas_flag $gcc_ld_flag -O2 -flto -fuse-linker-plugin -Wl,-rpath-link,. -Wl,--no-copy-dt-needed-entries -Wl,--no-as-needed tmpdir/pr15146d.o tmpdir/pr15146c.so"]

ld/testsuite/lib/ld-lib.exp

@@ -1679,6 +1679,45 @@ proc check_lto_available { } {
     return $lto_available_saved
 }
 
+# Returns true if the target compiler supports LTO and -shared
+proc check_lto_shared_available { } {
+    global lto_shared_available_saved
+    global CC
+
+    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]"
+    }
+
+    if {![info exists lto_shared_available_saved]} {
+	# Check if gcc supports -flto -fuse-linker-plugin -shared
+	if { [which $CC] == 0 } {
+	    set lto_shared_available_saved 0
+	    return 0
+	}
+	set basename "lto_shared"
+	set src ${basename}[pid].c
+	set output ${basename}[pid].so
+	set f [open $src "w"]
+	puts $f ""
+	close $f
+	set status [remote_exec host $CC "$flags -shared -fPIC -B[pwd]/tmpdir/ld/ -flto -fuse-linker-plugin $src -o $output"]
+	if { [lindex $status 0] == 0 } {
+	    set lto_shared_available_saved 1
+	} else {
+	    set lto_shared_available_saved 0
+	}
+	file delete $src
+	file delete $output
+    }
+    return $lto_shared_available_saved
+}
+
 # Check if the assembler supports CFI statements.
 
 proc check_as_cfi { } {