binutils-gdb/gdb/complaints.h
Pedro Alves 62d7ae9234 Avoid expensive complaint calls when complaints are disabled
Running perf on "gdb -nx -readnow -batch gdb", I'm seeing a lot of
time (24%.75!) spent in gettext, via complaints.  'perf report -g' shows:

 -   86.23%     0.00%  gdb      gdb                     [.] gdb_main
    - gdb_main
       - 85.60% catch_command_errors
            symbol_file_add_main_adapter
            symbol_file_add_main
            symbol_file_add_main_1
            symbol_file_add
          - symbol_file_add_with_addrs
             - 84.31% dw2_expand_all_symtabs
                - dw2_instantiate_symtab
                   - 83.79% dw2_do_instantiate_symtab
                      - 70.85% process_die
                         - 41.11% dwarf_decode_macros
                            - 41.09% dwarf_decode_macro_bytes
                               - 39.74% dwarf_decode_macro_bytes
   >>>>>>>>>>>>>>>>>>>>>>>        + 24.75% __dcigettext              <<<<<<<
                                  + 7.37% macro_define_object_internal
                                  + 3.16% macro_define_function
                                    0.77% splay_tree_insert
                                  + 0.76% savestring
                                  + 0.58% free
                                    0.53% read_indirect_string_at_offset_from
                                 0.54% macro_define_object_internal
                                 0.51% macro_start_file
                         + 25.57% process_die
                         + 4.07% dwarf_decode_lines
                      + 4.28% compute_delayed_physnames
                      + 3.85% end_symtab_from_static_block
                      + 3.38% load_cu
                      + 1.29% end_symtab_get_static_block
                   + 0.52% do_my_cleanups
             + 1.29% read_symbols
       + 0.54% gdb_init

The problem is that we're always computing the arguments to pass to
complaint, including passing the format strings through gettext, even
when complaints are disabled.  As seen above, gettext can be quite
expensive.

Fix this by wrapping complaint in a macro that skips the real
complaint call when complaints are disabled.

This improves "gdb -nx -readnow -batch gdb" from
 ~11.0s => ~7.8s with -O2 -g3, and
  ~6.0s => ~5.3s with -O2 -g.
w/ gcc 5.3.1, on x86_64, for me.

gdb/ChangeLog:
2017-11-08  Pedro Alves  <palves@redhat.com>

	* complaints.c (stop_whining): Make extern.
	(complaint): Rename to ...
	(complaint_internal): ... this.
	* complaints.h (complaint): Rename to ...
	(complaint_internal): ... this.
	(complaint): Reimplement as macro around complaint_internal.

gdb/testsuite/ChangeLog:
2017-11-08  Pedro Alves  <palves@redhat.com>

	* gdb.gdb/complaints.exp (test_initial_complaints)
	(test_serial_complaints, test_short_complaints): Call
	complaint_internal instead of complaint.
2017-11-08 23:42:11 +00:00

68 lines
2.3 KiB
C

/* Definitions for complaint handling during symbol reading in GDB.
Copyright (C) 1990-2017 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#if !defined (COMPLAINTS_H)
#define COMPLAINTS_H
/* Opaque object used to track the number of complaints of a
particular category. */
struct complaints;
/* Predefined categories. */
extern struct complaints *symfile_complaints;
/* Helper for complaint. */
extern void complaint_internal (struct complaints **complaints,
const char *fmt, ...)
ATTRIBUTE_PRINTF (2, 3);
/* Register a complaint. This is a macro around complaint_internal to
avoid computing complaint's arguments when complaints are disabled.
Running FMT via gettext [i.e., _(FMT)] can be quite expensive, for
example. */
#define complaint(COMPLAINTS, FMT, ...) \
do \
{ \
extern int stop_whining; \
\
if (stop_whining > 0) \
complaint_internal (COMPLAINTS, FMT, ##__VA_ARGS__); \
} \
while (0)
extern void internal_complaint (struct complaints **complaints,
const char *file, int line,
const char *fmt,
...) ATTRIBUTE_PRINTF (4, 5);
/* Clear out / initialize all complaint counters that have ever been
incremented. If LESS_VERBOSE is 1, be less verbose about
successive complaints, since the messages are appearing all
together during a command that is reporting a contiguous block of
complaints (rather than being interleaved with other messages). If
noisy is 1, we are in a noisy command, and our caller will print
enough context for the user to figure it out. */
extern void clear_complaints (struct complaints **complaints,
int less_verbose, int noisy);
#endif /* !defined (COMPLAINTS_H) */