Make __builtin_return_address(0) work with -fstack-protector. Old diff

from Jakub Jelinek that never made it into upstream GCC.  Fixes ld.so.
Found by drahn@ and me; ok miod@

diff --git a/gnu/gcc/gcc/config/rs6000/rs6000.c b/gnu/gcc/gcc/config/rs6000/rs6000.c
index 6670a20..aa6580f 100644 (file)
--- a/gnu/gcc/gcc/config/rs6000/rs6000.c
+++ b/gnu/gcc/gcc/config/rs6000/rs6000.c
@@ -13475,17 +13475,22 @@ rs6000_return_addr (int count, rtx frame)
      don't try to be too clever here.  */
   if (count != 0 || (DEFAULT_ABI != ABI_AIX && flag_pic))
     {
+      rtx x;
       cfun->machine->ra_needs_full_frame = 1;
 
-      return
-       gen_rtx_MEM
-         (Pmode,
-          memory_address
-          (Pmode,
-           plus_constant (copy_to_reg
-                          (gen_rtx_MEM (Pmode,
-                                        memory_address (Pmode, frame))),
-                          RETURN_ADDRESS_OFFSET)));
+      if (count == 0)
+       {
+         gcc_assert (frame == frame_pointer_rtx);
+         x = arg_pointer_rtx;
+       }
+      else
+        {
+         x = memory_address (Pmode, frame);
+         x = copy_to_reg (gen_rtx_MEM (Pmode, x));
+       }
+
+      x = plus_constant (x, RETURN_ADDRESS_OFFSET);
+      return gen_rtx_MEM (Pmode, memory_address (Pmode, x));
     }
 
   cfun->machine->ra_need_lr = 1;