binutils-gdb/gdb/bt-utils.h
Andrew Burgess b77a357567 gdb: fix some #ifdef logic in bt-utils.h
In passing I spotted some incorrect #ifdef logic in bt-utils.h.  The
logic in question has existed since the file was originally added in
commit:

  commit abbbd4a3e0
  Date:   Wed Aug 11 13:24:33 2021 +0100

      gdb: use libbacktrace to create a better backtrace for fatal signals

The code is trying to select between using libbacktrace or using the
execinfo supplied backtrace API.

First we check to see if we can use libbacktrace.  If we can then we
include some header files, and then set some defines to indicate that
libbacktrace is being used.

Then we check if execinfo is available, if it is then we include
<execinfo.h> and set some alternative defines.

In theory the second block of logic should not trigger if the first
block (that uses libbacktrace) has also triggered, but we incorrectly
check the define 'PRINT_BACKTRACE_ON_FATAL_SIGNAL' instead of checking
for 'GDB_PRINT_INTERNAL_BACKTRACE_USING_LIBBACKTRACE', so the second
block triggers more than it should.  The
'PRINT_BACKTRACE_ON_FATAL_SIGNAL' define is not defined anywhere, this
was a mistake in the original commit.

In reality this is harmless, we include <execinfo.h> when we don't
need too, but in by-utils.c the libbacktrace define is always checked
for before the execinfo define, so we never actually end up using the
execinfo path (when libbacktrace is available).  But I figure its
still worth cleaning this up.

I've tested GDB in a "default" build where libbacktrace is used, and
when configuring with --disable-libbacktrace which causes the execinfo
backtrace API to be used instead, both still appear to work fine.

There should be no user visible changes after this commit.
2023-01-04 11:36:57 +00:00

75 lines
2.7 KiB
C

/* Copyright (C) 2021-2023 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/>. */
/* Support for printing a backtrace when GDB hits an error. This is not
for printing backtraces of the inferior, but backtraces of GDB itself. */
#ifndef BT_UTILS_H
#define BT_UTILS_H
#ifdef HAVE_LIBBACKTRACE
# include "backtrace.h"
# include "backtrace-supported.h"
# if BACKTRACE_SUPPORTED && (! BACKTRACE_USES_MALLOC)
# define GDB_PRINT_INTERNAL_BACKTRACE
# define GDB_PRINT_INTERNAL_BACKTRACE_USING_LIBBACKTRACE
# endif
#endif
#if defined HAVE_EXECINFO_H \
&& defined HAVE_EXECINFO_BACKTRACE \
&& !defined GDB_PRINT_INTERNAL_BACKTRACE_USING_LIBBACKTRACE
# include <execinfo.h>
# define GDB_PRINT_INTERNAL_BACKTRACE
# define GDB_PRINT_INTERNAL_BACKTRACE_USING_EXECINFO
#endif
/* Define GDB_PRINT_INTERNAL_BACKTRACE_INIT_ON. This is a boolean value
that can be used as an initial value for a set/show user setting, where
the setting controls printing a GDB internal backtrace.
If backtrace printing is supported then this will have the value true,
but if backtrace printing is not supported then this has the value
false. */
#ifdef GDB_PRINT_INTERNAL_BACKTRACE
# define GDB_PRINT_INTERNAL_BACKTRACE_INIT_ON true
#else
# define GDB_PRINT_INTERNAL_BACKTRACE_INIT_ON false
#endif
/* Print a backtrace of the current GDB process to the current
gdb_stderr. The output is done in a signal async manner, so it is safe
to call from signal handlers. */
extern void gdb_internal_backtrace ();
/* A generic function that can be used as the set function for any set
command that enables printing of an internal backtrace. Command C must
be a boolean set command.
If GDB doesn't support printing a backtrace, and the user has tried to
set the variable associated with command C to true, then the associated
variable will be set back to false, and an error thrown.
If GDB does support printing a backtrace then this function does
nothing. */
extern void gdb_internal_backtrace_set_cmd (const char *args, int from_tty,
cmd_list_element *c);
#endif /* BT_UTILS_H */