Any objections to backporting these fixes to the 4.9 branch?
-cary
On Tue, Jul 1, 2014 at 2:37 PM, Cary Coutant <ccout...@google.com> wrote:
> This patch fixes a couple of ICEs when using -gsplit-dwarf.
>
> When compiling a small-enough compilation unit that has no address table
> entries, but complex enough that -freorder-blocks-and-partition produces
> location lists, dwarf2out_finish does not call index_location_lists, but
> optimize_location_lists will later assume that the addr_index_table has
> been indexed.
> Google ref: b/15417905
>
> When resolve_addr_in_expr replaces a CONST_STRING rtx, it directly
> updates the pointer to the old expression with the new one. In the
> case of a DW_OP_GNU_addr_index or DW_OP_GNU_const_index, that pointer
> may be in an address table entry, which is keyed by the rtx. Instead
> of directly replacing the pointer, we need to remove the old address
> table entry (i.e., decrement its reference count), and add a new one.
> Google ref: b/15957101
>
> Bootstrapped with no new regressions, and committed as r212211.
>
> -cary
>
>
> 2014-07-01 Cary Coutant <ccout...@google.com>
>
> gcc/
> * dwarf2out.c (remove_addr_table_entry): Remove unnecessary hash table
> lookup.
> (resolve_addr_in_expr): When replacing the rtx in a location list
> entry, get a new address table entry.
> (dwarf2out_finish): Call index_location_lists even if there are no
> addr_index_table entries yet.
>
>
> diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> index 8caf940..94e98a1 100644
> --- a/gcc/dwarf2out.c
> +++ b/gcc/dwarf2out.c
> @@ -4222,13 +4222,10 @@ add_addr_table_entry (void *addr, enum ate_kind kind)
> static void
> remove_addr_table_entry (addr_table_entry *entry)
> {
> - addr_table_entry *node;
> -
> gcc_assert (dwarf_split_debug_info && addr_index_table);
> - node = (addr_table_entry *) htab_find (addr_index_table, entry);
> /* After an index is assigned, the table is frozen. */
> - gcc_assert (node->refcount > 0 && node->index == NO_INDEX_ASSIGNED);
> - node->refcount--;
> + gcc_assert (entry->refcount > 0 && entry->index == NO_INDEX_ASSIGNED);
> + entry->refcount--;
> }
>
> /* Given a location list, remove all addresses it refers to from the
> @@ -23102,11 +23099,16 @@ resolve_addr_in_expr (dw_loc_descr_ref loc)
> break;
> case DW_OP_GNU_addr_index:
> case DW_OP_GNU_const_index:
> - if ((loc->dw_loc_opc == DW_OP_GNU_addr_index
> - || (loc->dw_loc_opc == DW_OP_GNU_const_index && loc->dtprel))
> - && resolve_one_addr (&loc->dw_loc_oprnd1.val_entry->addr.rtl,
> - NULL))
> - return false;
> + if (loc->dw_loc_opc == DW_OP_GNU_addr_index
> + || (loc->dw_loc_opc == DW_OP_GNU_const_index && loc->dtprel))
> + {
> + rtx rtl = loc->dw_loc_oprnd1.val_entry->addr.rtl;
> + if (resolve_one_addr (&rtl, NULL))
> + return false;
> + remove_addr_table_entry (loc->dw_loc_oprnd1.val_entry);
> + loc->dw_loc_oprnd1.val_entry =
> + add_addr_table_entry (rtl, ate_kind_rtx);
> + }
> break;
> case DW_OP_const4u:
> case DW_OP_const8u:
> @@ -24198,18 +24200,23 @@ dwarf2out_finish (const char *filename)
> dwarf_strict ? DW_AT_macro_info : DW_AT_GNU_macros,
> macinfo_section_label);
>
> - if (dwarf_split_debug_info && addr_index_table != NULL)
> + if (dwarf_split_debug_info)
> {
> /* optimize_location_lists calculates the size of the lists,
> so index them first, and assign indices to the entries.
> Although optimize_location_lists will remove entries from
> the table, it only does so for duplicates, and therefore
> only reduces ref_counts to 1. */
> - unsigned int index = 0;
> index_location_lists (comp_unit_die ());
> - htab_traverse_noresize (addr_index_table,
> - index_addr_table_entry, &index);
> +
> + if (addr_index_table != NULL)
> + {
> + unsigned int index = 0;
> + htab_traverse_noresize (addr_index_table,
> + index_addr_table_entry, &index);
> + }
> }
> +
> if (have_location_lists)
> optimize_location_lists (comp_unit_die ());
>
