Add "ld -r" tests for PR ld/15323

Weak defined function is turned into non-weak defined function by
"ld -r -flto" with GCC 5 due to a GCC 5 regression:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67548

Add "ld -r" tests for PR ld/15323 to make sure that any linker change
won't introduce linker regression for PR ld/15323.

	* ld-plugin/lto.exp (lto_link_tests): Add a "ld -r" test for
	PR ld/15323.
	(lto_run_tests): Add a "ld -r" test for PR ld/15323.

ld/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2015-09-11  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* ld-plugin/lto.exp (lto_link_tests): Add a "ld -r" test for
+	PR ld/15323.
+	(lto_run_tests): Add a "ld -r" test for PR ld/15323.
+
 2015-09-09  Jiong Wang  <jiong.wang@arm.com>
 
 	* ld-aarch64/tls-relax-ld-le-tiny.s: New testcase.

ld/testsuite/ld-plugin/lto.exp

@@ -160,9 +160,12 @@ set lto_link_tests [list \
   [list "PR ld/13287" \
    "-flto -fuse-linker-plugin -Wl,--as-needed" "-flto" \
    {pr13287.cc} {} "pr13287.exe" "c++"] \
-  [list "PR ld/15323" \
+  [list "PR ld/15323 (1)" \
    "" "-O2" \
    {pr15323a.c} {} "" "c"] \
+  [list "PR ld/15323 (2)" \
+   "-O2 -flto -r -nostdlib" "-O2 -flto" \
+   {pr15323a.c} {} "pr15323a-r.o" "c"] \
   [list "Compile(1) PR ld/pr16846" \
    "" "-flto" \
    {pr16846a.c pr16846b.c} {} ""] \
@@ -315,9 +318,12 @@ set lto_run_tests [list \
   [list "PR ld/13201" \
    "-O2 -flto -fuse-linker-plugin -Wl,--as-needed tmpdir/pr13201.o -lm" "" \
    {dummy.c} "pr13201.exe" "pr13201.out" "" "c"] \
-  [list "PR ld/15323" \
+  [list "PR ld/15323 (3)" \
    "-O2 -flto -fuse-linker-plugin tmpdir/pr15323a.o" "" \
    {pr15323b.c} "pr15323.exe" "pr15323.out" "-flto -O2" "c"] \
+  [list "PR ld/15323 (4)" \
+   "-O2 -flto tmpdir/pr15323a-r.o" "" \
+   {dummy.c} "pr15323a.exe" "pr15323.out" "-flto -O2" "c"] \
 ]
 
 if { [at_least_gcc_version 4 7] } {

ld/testsuite/ld-plugin/pr15323a.c

@@ -1,14 +1,23 @@
 #include <stdio.h>
 
 int x;
+int y;
 
 __attribute__((weak))
-void foobar (void) { x++; }
+void foobar (void) { y++; x++; }
 
 int main (void)
 {
   foobar ();
-  if (x == -1)
-    printf ("OK\n");
+  if (y == 0)
+    {
+      if (x == -1)
+	printf ("OK\n");
+    }
+  else
+    {
+      if (x == 1)
+	printf ("OK\n");
+    }
   return 0;
 }