[PATCH] Fix DW_OP_GNU_implicit_pointer referring to DW_TAG_dwarf_procedure (PR debug/69947)

[Jakub Jelinek]

On Thu, Feb 25, 2016 at 04:53:58PM +0100, Pierre-Marie de Rodat wrote:
> I introduced a DW_OP_call* traversal for this:
> 
>   * prune_unused_types_mark traverses attributes using
>     prune_unused_types_walk_attribs;
> 
>   * …_walk_attribs walks location descriptions and location lists using
>     …_walk_loc_descr
> 
>   * …_walk_loc_descr marks DWARF procedures referenced by DW_OP_call*
>     operations.

Ah, I've been looking for something that would set die_perennial_p, but
actually you just set die_mark later on instead for those.
So IMHO the right fix is just handle all the ops that could directly or
indirectly contain references to other DIEs, rather than just handling
the 3 you have there.

Going to bootstrap/regtest this on x86_64-linux and i686-linux now.

Is this ok for trunk if it passes testing?

2016-02-25  Jakub Jelinek  <ja...@redhat.com>

        PR debug/69947
        * dwarf2out.c (prune_unused_types_walk_loc_descr): Handle
        all other ops that have dw_val_class_die_ref operands,
        and DW_OP_GNU_entry_value.

        * gcc.dg/guality/pr69947.c: New test.

--- gcc/dwarf2out.c.jj  2016-02-25 17:04:11.465781368 +0100
+++ gcc/dwarf2out.c     2016-02-25 17:41:26.785371399 +0100
@@ -25641,11 +25641,29 @@ prune_unused_types_walk_loc_descr (dw_lo
   for (; loc != NULL; loc = loc->dw_loc_next)
     switch (loc->dw_loc_opc)
       {
+      case DW_OP_GNU_implicit_pointer:
+      case DW_OP_GNU_convert:
+      case DW_OP_GNU_reinterpret:
+       if (loc->dw_loc_oprnd1.val_class == dw_val_class_die_ref)
+         prune_unused_types_mark (loc->dw_loc_oprnd1.v.val_die_ref.die, 1);
+       break;
       case DW_OP_call2:
       case DW_OP_call4:
       case DW_OP_call_ref:
+      case DW_OP_GNU_const_type:
+      case DW_OP_GNU_parameter_ref:
+       gcc_assert (loc->dw_loc_oprnd1.val_class == dw_val_class_die_ref);
        prune_unused_types_mark (loc->dw_loc_oprnd1.v.val_die_ref.die, 1);
        break;
+      case DW_OP_GNU_regval_type:
+      case DW_OP_GNU_deref_type:
+       gcc_assert (loc->dw_loc_oprnd2.val_class == dw_val_class_die_ref);
+       prune_unused_types_mark (loc->dw_loc_oprnd2.v.val_die_ref.die, 1);
+       break;
+      case DW_OP_GNU_entry_value:
+       gcc_assert (loc->dw_loc_oprnd1.val_class == dw_val_class_loc);
+       prune_unused_types_walk_loc_descr (loc->dw_loc_oprnd1.v.val_loc);
+       break;
       default:
        break;
       }
--- gcc/testsuite/gcc.dg/guality/pr69947.c.jj   2016-02-25 17:22:13.729098931 
+0100
+++ gcc/testsuite/gcc.dg/guality/pr69947.c      2016-02-25 17:22:13.729098931 
+0100
@@ -0,0 +1,22 @@
+/* PR debug/69947 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+
+#include "../nop.h"
+
+static const char *c = "foobar";
+
+__attribute__((noinline, noclone)) void
+foo (void)
+{
+  static const char a[] = "abcdefg";
+  const char *b = a;           /* { dg-final { gdb-test 14 "c\[2\]" "'o'" } } 
*/
+  asm (NOP : : : "memory");    /* { dg-final { gdb-test 14 "b\[4\]" "'e'" } } 
*/
+}
+
+int
+main ()
+{
+  foo ();
+  return 0;
+}


        Jakub