Run IFUNC run-time tests only if IFUNC is supported

* lib/ld-lib.exp (check_ifunc_available): New.
	* ld-ifunc/ifunc.exp: Run IFUNC run-time tests only if IFUNC
	is supported.

ld/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2014-11-20  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* lib/ld-lib.exp (check_ifunc_available): New.
+	* ld-ifunc/ifunc.exp: Run IFUNC run-time tests only if IFUNC
+	is supported.
+
 2014-11-20  Terry Guo  <terry.guo@arm.com>
 
 	* ld-arm/attr-merge-nosection-1.d: New file.

ld/testsuite/ld-ifunc/ifunc.exp

@@ -404,6 +404,21 @@ run_ld_link_exec_tests [] [list \
 	"ifunc-common-1.out" \
 	"-g" \
     ] \
+]
+
+set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
+foreach t $test_list {
+    # We need to strip the ".d", but can leave the dirname.
+    verbose [file rootname $t]
+    run_dump_test [file rootname $t]
+}
+
+# Run-time tests which require working IFUNC support.
+if { ![check_ifunc_available] } {
+    return
+}
+
+run_ld_link_exec_tests [] [list \
     [list \
 	"Run pr16467" \
 	"tmpdir/pr16467c.o tmpdir/libpr16467b.so tmpdir/libpr16467a.so" \
@@ -414,10 +429,3 @@ run_ld_link_exec_tests [] [list \
 	"" \
     ] \
 ]
-
-set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
-foreach t $test_list {
-    # We need to strip the ".d", but can leave the dirname.
-    verbose [file rootname $t]
-    run_dump_test [file rootname $t]
-}

ld/testsuite/lib/ld-lib.exp

@@ -1820,6 +1820,53 @@ proc check_as_cfi { } {
     return $success
 }
 
+# Returns true if IFUNC works.
+
+proc check_ifunc_available { } {
+    global ifunc_available_saved
+    global CC
+
+    if {![info exists ifunc_available_saved]} {
+        if { [which $CC] == 0 } {
+	    set ifunc_available_saved 0
+	    return 0
+	}
+	# Check if gcc supports -flto -fuse-linker-plugin
+	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/ifunc[pid]"
+	set src ${basename}.c
+	set output ${basename}.out
+	set f [open $src "w"]
+	puts $f "extern int library_func2 (void);"
+	puts $f "int main (void)"
+	puts $f "{"
+	puts $f "  if (library_func2 () != 2) __builtin_abort ();"
+	puts $f "  return 0; "
+	puts $f "}"
+	puts $f "static int library_func1 (void) {return 2; }"
+	puts $f "void *foo (void) __asm__ (\"library_func2\");"
+	puts $f "void *foo (void) { return library_func1; }"
+	puts $f "__asm__(\".type library_func2, %gnu_indirect_function\");"
+	close $f
+	remote_download host $src
+	set ifunc_available_saved [run_host_cmd_yesno "$CC" "$flags $src -o $output"]
+	if { $ifunc_available_saved == 1 } {
+	  set ifunc_available_saved [run_host_cmd_yesno "$output" ""]
+	}
+	remote_file host delete $src
+	remote_file host delete $output
+	file delete $src
+    }
+    return $ifunc_available_saved
+}
+
 # Provide virtual target "cfi" for targets supporting CFI.
 
 rename "istarget" "istarget_ld"