[Crash-utility] Speed up list/tree '-s' output.
Alexandr Terekhov
Alexandr_Terekhov at epam.com
Wed Aug 24 05:45:46 UTC 2016
Hi Dave,
here is patch with arguments instead of static variables:
--- gdb-7.6.orig/gdb/symtab.c 2016-08-18 09:06:33.000000000 +0300
+++ gdb-7.6/gdb/symtab.c 2016-08-24 08:40:45.700772046 +0300
@@ -5122,7 +5122,7 @@
#define GDB_COMMON
#include "../../defs.h"
-static void get_member_data(struct gnu_request *, struct type *);
+static void get_member_data(struct gnu_request *, struct type *, long, char);
static void dump_enum(struct type *, struct gnu_request *);
static void eval_enum(struct type *, struct gnu_request *);
static void gdb_get_line_number(struct gnu_request *);
@@ -5327,7 +5327,7 @@
req->typecode = TYPE_CODE(sym->type);
req->length = TYPE_LENGTH(sym->type);
if (req->member)
- get_member_data(req, sym->type);
+ get_member_data(req, sym->type, 0, 1);
if (TYPE_CODE(sym->type) == TYPE_CODE_ENUM) {
if (req->flags & GNU_PRINT_ENUMERATORS)
@@ -5397,7 +5397,7 @@
}
if (req->member)
- get_member_data(req, type);
+ get_member_data(req, type, 0, 1);
break;
@@ -5480,7 +5480,7 @@
* member field, and when found, return its relevant data.
*/
static void
-get_member_data(struct gnu_request *req, struct type *type)
+get_member_data(struct gnu_request *req, struct type *type, long offset, char is_first)
{
register short i;
struct field *nextfield;
@@ -5492,7 +5492,7 @@
nfields = TYPE_MAIN_TYPE(type)->nfields;
nextfield = TYPE_MAIN_TYPE(type)->flds_bnds.fields;
- if (nfields == 0) {
+ if (nfields == 0 && is_first /* The first call */) {
struct type *newtype;
newtype = lookup_transparent_type(req->name);
if (newtype) {
@@ -5505,13 +5505,18 @@
for (i = 0; i < nfields; i++) {
if (STREQ(req->member, nextfield->name)) {
- req->member_offset = nextfield->loc.bitpos;
+ req->member_offset = offset + nextfield->loc.bitpos;
req->member_length = TYPE_LENGTH(nextfield->type);
req->member_typecode = TYPE_CODE(nextfield->type);
if ((req->member_typecode == TYPE_CODE_TYPEDEF) &&
(typedef_type = check_typedef(nextfield->type)))
req->member_length = TYPE_LENGTH(typedef_type);
return;
+ } else if (*nextfield->name == 0) { /* Anonymous struct/union */
+ get_member_data(req, nextfield->type,
+ offset + nextfield->loc.bitpos, 0);
+ if (req->member_offset != -1)
+ return;
}
nextfield++;
}
@@ -5706,7 +5711,7 @@
}
if (req->member)
- get_member_data(req, type);
+ get_member_data(req, type, 0, 1);
do_cleanups (old_chain);
}
Thanks,
Alexandr
________________________________________
From: crash-utility-bounces at redhat.com <crash-utility-bounces at redhat.com> on behalf of Dave Anderson <anderson at redhat.com>
Sent: Tuesday, August 23, 2016 23:17
To: Discussion list for crash utility usage, maintenance and development
Subject: Re: [Crash-utility] Speed up list/tree '-s' output.
Hi Alexandr,
I'm still testing and sanity-checking the symtab.c patch given that it's
modifying such a commonly-called function. Interestingly enough, it's
actually uncovered a bug with the current determination of the page.list
members, which I found by saving the output of "help -o" into a file,
both without and then with your patch, into /tmp/old and /tmp/new, and
then diff'ed the two files:
# diff /tmp/old /tmp/new
221,223c221,223
< page_list: -1
< page_list_next: -1
< page_list_prev: -1
---
> page_list: 32
> page_list_next: 32
> page_list_prev: 40
#
Fortunately those fields aren't used by the crash code for more recent
kernels, which have gone crazy with the anonymous structures in the page
structure. But anyway, that was a good catch by your patch.
On the other hand, I don't like the use of the deep and offset static
variables, because there's always the remote possibility that a
CTRL-C or other function failure may happen while they are set, and
then leave them in a bogus state. So I would rather they get passed as
arguments.
Thanks,
Dave
----- Original Message -----
> Hi Dave,
>
> here is updated patch for gdb/symtab.c:
>
> --- gdb-7.6.orig/gdb/symtab.c 2016-08-18 09:06:33.000000000 +0300
> +++ gdb-7.6/gdb/symtab.c 2016-08-23 14:28:45.456510348 +0300
> @@ -5486,13 +5486,15 @@
> struct field *nextfield;
> short nfields;
> struct type *typedef_type;
> + static int deep = 0;
> + static long offset = 0;
>
> req->member_offset = -1;
>
> nfields = TYPE_MAIN_TYPE(type)->nfields;
> nextfield = TYPE_MAIN_TYPE(type)->flds_bnds.fields;
>
> - if (nfields == 0) {
> + if (nfields == 0 && deep == 0 /* The first call */) {
> struct type *newtype;
> newtype = lookup_transparent_type(req->name);
> if (newtype) {
> @@ -5505,13 +5507,21 @@
>
> for (i = 0; i < nfields; i++) {
> if (STREQ(req->member, nextfield->name)) {
> - req->member_offset = nextfield->loc.bitpos;
> + req->member_offset = offset + nextfield->loc.bitpos;
> req->member_length = TYPE_LENGTH(nextfield->type);
> req->member_typecode = TYPE_CODE(nextfield->type);
> if ((req->member_typecode == TYPE_CODE_TYPEDEF) &&
> (typedef_type = check_typedef(nextfield->type)))
> req->member_length = TYPE_LENGTH(typedef_type);
> return;
> + } else if (*nextfield->name == 0) { /* Anonymous struct/union */
> + deep++;
> + offset += nextfield->loc.bitpos;
> + get_member_data(req, nextfield->type);
> + offset -= nextfield->loc.bitpos;
> + deep--;
> + if (req->member_offset != -1)
> + return;
> }
> nextfield++;
> }
> @@ -5705,7 +5715,7 @@
> req->target_length = target_type->length;
> }
>
> - if (req->member)
> + if (req->member)
> get_member_data(req, type);
>
> do_cleanups (old_chain);
>
> The patch for crash tool can be found on github:
> https://raw.githubusercontent.com/hziSot/crash-patches/41abc6f9c91c2a602973ff9564234395deadb80e/crash_speed_up_tree_list.patch
>
> Thanks,
> Alexandr
>
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
>
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