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From: "steven at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug pch/53880] [4.8 Regression] compile time regression when generating precompiled headers for boost
Date: Mon, 30 Jul 2012 13:52:00 -0000 [thread overview]
Message-ID: <bug-53880-4-HVDoyj15An@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53880-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53880
--- Comment #27 from Steven Bosscher <steven at gcc dot gnu.org> 2012-07-30 13:51:58 UTC ---
The problem is the quadratic behavior invoked by the loop in
gt_pch_nx_line_maps:
{
size_t l2 = (size_t)(((*x).info_macro).used);
if ((*x).info_macro.maps != NULL) {
size_t i2;
for (i2 = 0; i2 != (size_t)(l2); i2++) {
switch (((*x).info_macro.maps[i2]).reason == LC_ENTER_MACRO)
{
case 0:
gt_pch_n_S ((*x).info_macro.maps[i2].d.ordinary.to_file);
break;
case 1:
{
union tree_node * const x3 =
((*x).info_macro.maps[i2].d.macro.macro) ?
HT_IDENT_TO_GCC_IDENT (HT_NODE (((*x).info_macro.maps[i2].d.macro.macro))) :
NULL;
gt_pch_n_9tree_node (x3);
}
if ((*x).info_macro.maps[i2].d.macro.macro_locations != NULL) {
gt_pch_note_object
((*x).info_macro.maps[i2].d.macro.macro_locations, x, gt_pch_p_9line_maps,
gt_types_enum_last);
}
break;
default:
break;
}
}
and the loop in gt_pch_p_9line_maps:
size_t l2 = (size_t)(((*x).info_macro).used);
if ((*x).info_macro.maps != NULL) {
size_t i2;
for (i2 = 0; i2 != (size_t)(l2); i2++) {
switch (((*x).info_macro.maps[i2]).reason == LC_ENTER_MACRO)
{
case 0:
if ((void *)((*x).info_macro.maps) == this_obj)
op (&((*x).info_macro.maps[i2].d.ordinary.to_file), cookie);
break;
case 1:
{
union tree_node * x3 =
((*x).info_macro.maps[i2].d.macro.macro) ?
HT_IDENT_TO_GCC_IDENT (HT_NODE (((*x).info_macro.maps[i2].d.macro.macro))) :
NULL;
if ((void *)((*x).info_macro.maps) == this_obj)
op (&(x3), cookie);
(*x).info_macro.maps[i2].d.macro.macro = (x3) ? CPP_HASHNODE
(GCC_IDENT_TO_HT_IDENT ((x3))) : NULL;
}
if ((*x).info_macro.maps[i2].d.macro.macro_locations != NULL) {
if ((void *)((*x).info_macro.maps) == this_obj)
op (&((*x).info_macro.maps[i2].d.macro.macro_locations),
cookie);
}
break;
default:
break;
}
}
The first loop registers every line map entry to be visited for pointer
rewriting later by gt_pch_p_9line_maps:
gt_pch_note_object ((*x).info_macro.maps[i2].d.macro.macro_locations, x,
gt_pch_p_9line_maps, gt_types_enum_last);
where x==input.c:line_table, and
(*x).info_macro.maps[i2].d.macro.macro_locations is the "i2"'th entry.
The second loop is called from the loop in gt_pch_save via note_ptr_fn, which
is gt_pch_p_9line_maps:
state.ptrs[i]->note_ptr_fn (state.ptrs[i]->obj,
state.ptrs[i]->note_ptr_cookie,
relocate_ptrs, &state);
==
gt_pch_p_9line_maps((*x).info_macro.maps[i2].d.macro.macro_locations,
&line_table, relocate_ptrs, &state);
and gt_pch_p_9line_maps loops over all map elements until:
(void *)((*x).info_macro.maps) == this_obj
This causes (((*x).info_macro).used)**2 visits.
next prev parent reply other threads:[~2012-07-30 13:52 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-06 15:46 [Bug pch/53880] New: " markus at trippelsdorf dot de
2012-07-06 15:55 ` [Bug pch/53880] " markus at trippelsdorf dot de
2012-07-06 16:47 ` markus at trippelsdorf dot de
2012-07-08 7:08 ` markus at trippelsdorf dot de
2012-07-09 8:41 ` rguenth at gcc dot gnu.org
2012-07-23 13:46 ` paolo.carlini at oracle dot com
2012-07-23 21:29 ` steven at gcc dot gnu.org
2012-07-23 22:46 ` steven at gcc dot gnu.org
2012-07-24 6:50 ` markus at trippelsdorf dot de
2012-07-24 8:16 ` stevenb.gcc at gmail dot com
2012-07-24 9:20 ` steven at gcc dot gnu.org
2012-07-24 9:34 ` rguenth at gcc dot gnu.org
2012-07-24 9:41 ` stevenb.gcc at gmail dot com
2012-07-24 9:43 ` rguenth at gcc dot gnu.org
2012-07-24 10:03 ` stevenb.gcc at gmail dot com
2012-07-24 10:13 ` paolo.carlini at oracle dot com
2012-07-26 16:30 ` dodji at seketeli dot org
2012-07-26 17:15 ` dodji at seketeli dot org
2012-07-26 17:16 ` dodji at seketeli dot org
2012-07-26 17:16 ` dodji at seketeli dot org
2012-07-26 17:18 ` dodji at seketeli dot org
2012-07-26 19:45 ` stevenb.gcc at gmail dot com
2012-07-26 21:11 ` dodji at seketeli dot org
2012-07-30 9:11 ` steven at gcc dot gnu.org
2012-07-30 10:54 ` markus at trippelsdorf dot de
2012-07-30 11:08 ` steven at gcc dot gnu.org
2012-07-30 11:22 ` markus at trippelsdorf dot de
2012-07-30 12:03 ` steven at gcc dot gnu.org
2012-07-30 13:17 ` steven at gcc dot gnu.org
2012-07-30 13:52 ` steven at gcc dot gnu.org [this message]
2012-07-30 14:22 ` steven at gcc dot gnu.org
2012-07-30 15:04 ` steven at gcc dot gnu.org
2012-07-30 16:15 ` steven at gcc dot gnu.org
2012-07-30 16:26 ` markus at trippelsdorf dot de
2012-07-30 22:55 ` steven at gcc dot gnu.org
2012-07-31 9:21 ` steven at gcc dot gnu.org
2012-07-31 9:24 ` steven at gcc dot gnu.org
2012-07-31 10:36 ` markus at trippelsdorf dot de
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