[PATCH] Use chain_next on struct dw_loc_descr_node for GTY (PR debug/64511)

[Jakub Jelinek]

Hi!

The latest testcase from the PR ICEs on running out of stack during GC
collection, because we have a long chain of dw_loc_descr_nodes.
Am not adding the testcase to the testsuite because it looks too costly.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2015-01-22  Jakub Jelinek  <ja...@redhat.com>

        PR debug/64511
        * dwarf2out.c (struct dw_loc_descr_node): Add chain_next
        GTY markup.

--- gcc/dwarf2out.h.jj  2015-01-05 13:07:14.000000000 +0100
+++ gcc/dwarf2out.h     2015-01-22 14:58:52.448204612 +0100
@@ -205,7 +205,7 @@ struct GTY(()) dw_val_node {
 /* Locations in memory are described using a sequence of stack machine
    operations.  */
 
-struct GTY(()) dw_loc_descr_node {
+struct GTY((chain_next ("%h.dw_loc_next"))) dw_loc_descr_node {
   dw_loc_descr_ref dw_loc_next;
   ENUM_BITFIELD (dwarf_location_atom) dw_loc_opc : 8;
   /* Used to distinguish DW_OP_addr with a direct symbol relocation

        Jakub