544 lines
14 KiB
C
544 lines
14 KiB
C
/* Exception (throw catch) mechanism, for GDB, the GNU debugger.
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Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
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1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
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2009, 2010, 2011 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "exceptions.h"
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#include "breakpoint.h"
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#include "target.h"
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#include "inferior.h"
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#include "annotate.h"
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#include "ui-out.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include "serial.h"
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#include "gdbthread.h"
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const struct gdb_exception exception_none = { 0, GDB_NO_ERROR, NULL };
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/* Possible catcher states. */
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enum catcher_state {
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/* Initial state, a new catcher has just been created. */
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CATCHER_CREATED,
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/* The catch code is running. */
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CATCHER_RUNNING,
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CATCHER_RUNNING_1,
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/* The catch code threw an exception. */
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CATCHER_ABORTING
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};
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/* Possible catcher actions. */
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enum catcher_action {
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CATCH_ITER,
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CATCH_ITER_1,
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CATCH_THROWING
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};
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struct catcher
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{
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enum catcher_state state;
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/* Jump buffer pointing back at the exception handler. */
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EXCEPTIONS_SIGJMP_BUF buf;
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/* Status buffer belonging to the exception handler. */
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volatile struct gdb_exception *exception;
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/* Saved/current state. */
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int mask;
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struct ui_out *saved_uiout;
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struct cleanup *saved_cleanup_chain;
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/* Back link. */
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struct catcher *prev;
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};
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/* Where to go for throw_exception(). */
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static struct catcher *current_catcher;
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EXCEPTIONS_SIGJMP_BUF *
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exceptions_state_mc_init (struct ui_out *func_uiout,
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volatile struct gdb_exception *exception,
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return_mask mask)
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{
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struct catcher *new_catcher = XZALLOC (struct catcher);
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/* Start with no exception, save it's address. */
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exception->reason = 0;
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exception->error = GDB_NO_ERROR;
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exception->message = NULL;
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new_catcher->exception = exception;
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new_catcher->mask = mask;
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/* Override the global ``struct ui_out'' builder. */
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new_catcher->saved_uiout = uiout;
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uiout = func_uiout;
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/* Prevent error/quit during FUNC from calling cleanups established
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prior to here. */
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new_catcher->saved_cleanup_chain = save_cleanups ();
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/* Push this new catcher on the top. */
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new_catcher->prev = current_catcher;
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current_catcher = new_catcher;
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new_catcher->state = CATCHER_CREATED;
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return &new_catcher->buf;
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}
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static void
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catcher_pop (void)
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{
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struct catcher *old_catcher = current_catcher;
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current_catcher = old_catcher->prev;
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/* Restore the cleanup chain, the error/quit messages, and the uiout
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builder, to their original states. */
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restore_cleanups (old_catcher->saved_cleanup_chain);
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uiout = old_catcher->saved_uiout;
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xfree (old_catcher);
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}
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/* Catcher state machine. Returns non-zero if the m/c should be run
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again, zero if it should abort. */
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static int
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exceptions_state_mc (enum catcher_action action)
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{
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switch (current_catcher->state)
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{
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case CATCHER_CREATED:
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switch (action)
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{
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case CATCH_ITER:
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/* Allow the code to run the catcher. */
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current_catcher->state = CATCHER_RUNNING;
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return 1;
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default:
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internal_error (__FILE__, __LINE__, _("bad state"));
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}
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case CATCHER_RUNNING:
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switch (action)
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{
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case CATCH_ITER:
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/* No error/quit has occured. Just clean up. */
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catcher_pop ();
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return 0;
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case CATCH_ITER_1:
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current_catcher->state = CATCHER_RUNNING_1;
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return 1;
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case CATCH_THROWING:
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current_catcher->state = CATCHER_ABORTING;
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/* See also throw_exception. */
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return 1;
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default:
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internal_error (__FILE__, __LINE__, _("bad switch"));
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}
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case CATCHER_RUNNING_1:
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switch (action)
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{
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case CATCH_ITER:
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/* The did a "break" from the inner while loop. */
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catcher_pop ();
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return 0;
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case CATCH_ITER_1:
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current_catcher->state = CATCHER_RUNNING;
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return 0;
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case CATCH_THROWING:
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current_catcher->state = CATCHER_ABORTING;
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/* See also throw_exception. */
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return 1;
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default:
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internal_error (__FILE__, __LINE__, _("bad switch"));
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}
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case CATCHER_ABORTING:
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switch (action)
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{
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case CATCH_ITER:
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{
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struct gdb_exception exception = *current_catcher->exception;
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if (current_catcher->mask & RETURN_MASK (exception.reason))
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{
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/* Exit normally if this catcher can handle this
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exception. The caller analyses the func return
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values. */
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catcher_pop ();
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return 0;
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}
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/* The caller didn't request that the event be caught,
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relay the event to the next containing
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catch_errors(). */
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catcher_pop ();
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throw_exception (exception);
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}
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default:
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internal_error (__FILE__, __LINE__, _("bad state"));
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}
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default:
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internal_error (__FILE__, __LINE__, _("bad switch"));
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}
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}
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int
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exceptions_state_mc_action_iter (void)
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{
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return exceptions_state_mc (CATCH_ITER);
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}
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int
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exceptions_state_mc_action_iter_1 (void)
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{
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return exceptions_state_mc (CATCH_ITER_1);
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}
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/* Return EXCEPTION to the nearest containing catch_errors(). */
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void
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throw_exception (struct gdb_exception exception)
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{
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struct thread_info *tp = NULL;
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quit_flag = 0;
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immediate_quit = 0;
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if (!ptid_equal (inferior_ptid, null_ptid))
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tp = find_thread_ptid (inferior_ptid);
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/* Perhaps it would be cleaner to do this via the cleanup chain (not sure
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I can think of a reason why that is vital, though). */
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if (tp != NULL)
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{
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/* Clear queued breakpoint commands */
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bpstat_clear_actions (tp->control.stop_bpstat);
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}
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disable_current_display ();
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do_cleanups (ALL_CLEANUPS);
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/* Jump to the containing catch_errors() call, communicating REASON
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to that call via setjmp's return value. Note that REASON can't
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be zero, by definition in defs.h. */
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exceptions_state_mc (CATCH_THROWING);
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*current_catcher->exception = exception;
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EXCEPTIONS_SIGLONGJMP (current_catcher->buf, exception.reason);
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}
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static char *last_message;
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void
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deprecated_throw_reason (enum return_reason reason)
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{
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struct gdb_exception exception;
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memset (&exception, 0, sizeof exception);
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exception.reason = reason;
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switch (reason)
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{
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case RETURN_QUIT:
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break;
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case RETURN_ERROR:
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exception.error = GENERIC_ERROR;
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break;
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default:
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internal_error (__FILE__, __LINE__, _("bad switch"));
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}
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throw_exception (exception);
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}
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static void
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print_flush (void)
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{
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struct serial *gdb_stdout_serial;
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if (deprecated_error_begin_hook)
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deprecated_error_begin_hook ();
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target_terminal_ours ();
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/* We want all output to appear now, before we print the error. We
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have 3 levels of buffering we have to flush (it's possible that
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some of these should be changed to flush the lower-level ones
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too): */
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/* 1. The _filtered buffer. */
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wrap_here ("");
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/* 2. The stdio buffer. */
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gdb_flush (gdb_stdout);
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gdb_flush (gdb_stderr);
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/* 3. The system-level buffer. */
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gdb_stdout_serial = serial_fdopen (1);
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if (gdb_stdout_serial)
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{
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serial_drain_output (gdb_stdout_serial);
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serial_un_fdopen (gdb_stdout_serial);
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}
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annotate_error_begin ();
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}
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static void
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print_exception (struct ui_file *file, struct gdb_exception e)
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{
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/* KLUGE: cagney/2005-01-13: Write the string out one line at a time
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as that way the MI's behavior is preserved. */
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const char *start;
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const char *end;
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for (start = e.message; start != NULL; start = end)
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{
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end = strchr (start, '\n');
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if (end == NULL)
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fputs_filtered (start, file);
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else
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{
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end++;
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ui_file_write (file, start, end - start);
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}
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}
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fprintf_filtered (file, "\n");
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/* Now append the annotation. */
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switch (e.reason)
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{
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case RETURN_QUIT:
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annotate_quit ();
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break;
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case RETURN_ERROR:
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/* Assume that these are all errors. */
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annotate_error ();
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break;
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default:
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internal_error (__FILE__, __LINE__, _("Bad switch."));
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}
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}
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void
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exception_print (struct ui_file *file, struct gdb_exception e)
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{
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if (e.reason < 0 && e.message != NULL)
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{
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print_flush ();
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print_exception (file, e);
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}
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}
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void
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exception_fprintf (struct ui_file *file, struct gdb_exception e,
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const char *prefix, ...)
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{
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if (e.reason < 0 && e.message != NULL)
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{
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va_list args;
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print_flush ();
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/* Print the prefix. */
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va_start (args, prefix);
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vfprintf_filtered (file, prefix, args);
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va_end (args);
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print_exception (file, e);
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}
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}
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static void
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print_any_exception (struct ui_file *file, const char *prefix,
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struct gdb_exception e)
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{
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if (e.reason < 0 && e.message != NULL)
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{
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target_terminal_ours ();
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wrap_here (""); /* Force out any buffered output */
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gdb_flush (gdb_stdout);
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annotate_error_begin ();
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/* Print the prefix. */
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if (prefix != NULL && prefix[0] != '\0')
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fputs_filtered (prefix, file);
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print_exception (file, e);
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}
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}
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static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0)
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throw_it (enum return_reason reason, enum errors error, const char *fmt,
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va_list ap)
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{
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struct gdb_exception e;
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char *new_message;
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/* Save the message. Create the new message before deleting the
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old, the new message may include the old message text. */
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new_message = xstrvprintf (fmt, ap);
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xfree (last_message);
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last_message = new_message;
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/* Create the exception. */
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e.reason = reason;
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e.error = error;
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e.message = last_message;
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/* Throw the exception. */
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throw_exception (e);
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}
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void
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throw_verror (enum errors error, const char *fmt, va_list ap)
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{
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throw_it (RETURN_ERROR, error, fmt, ap);
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}
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void
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throw_vfatal (const char *fmt, va_list ap)
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{
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throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap);
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}
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void
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throw_error (enum errors error, const char *fmt, ...)
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{
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va_list args;
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va_start (args, fmt);
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throw_it (RETURN_ERROR, error, fmt, args);
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va_end (args);
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}
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/* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
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handler. If an exception (enum return_reason) is thrown using
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throw_exception() than all cleanups installed since
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catch_exceptions() was entered are invoked, the (-ve) exception
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value is then returned by catch_exceptions. If FUNC() returns
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normally (with a positive or zero return value) then that value is
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returned by catch_exceptions(). It is an internal_error() for
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FUNC() to return a negative value.
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See exceptions.h for further usage details.
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Must not be called with immediate_quit in effect (bad things might
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happen, say we got a signal in the middle of a memcpy to quit_return).
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This is an OK restriction; with very few exceptions immediate_quit can
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be replaced by judicious use of QUIT. */
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/* MAYBE: cagney/1999-11-05: catch_errors() in conjunction with
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error() et.al. could maintain a set of flags that indicate the the
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current state of each of the longjmp buffers. This would give the
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longjmp code the chance to detect a longjmp botch (before it gets
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to longjmperror()). Prior to 1999-11-05 this wasn't possible as
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code also randomly used a SET_TOP_LEVEL macro that directly
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initialize the longjmp buffers. */
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int
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catch_exceptions (struct ui_out *uiout,
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catch_exceptions_ftype *func,
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void *func_args,
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return_mask mask)
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{
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return catch_exceptions_with_msg (uiout, func, func_args, NULL, mask);
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}
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struct gdb_exception
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catch_exception (struct ui_out *uiout,
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catch_exception_ftype *func,
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void *func_args,
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return_mask mask)
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{
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volatile struct gdb_exception exception;
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TRY_CATCH (exception, mask)
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{
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(*func) (uiout, func_args);
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}
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return exception;
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}
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int
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catch_exceptions_with_msg (struct ui_out *uiout,
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catch_exceptions_ftype *func,
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void *func_args,
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char **gdberrmsg,
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return_mask mask)
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{
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volatile struct gdb_exception exception;
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volatile int val = 0;
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TRY_CATCH (exception, mask)
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{
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val = (*func) (uiout, func_args);
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}
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print_any_exception (gdb_stderr, NULL, exception);
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gdb_assert (val >= 0);
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gdb_assert (exception.reason <= 0);
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if (exception.reason < 0)
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{
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/* If caller wants a copy of the low-level error message, make
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one. This is used in the case of a silent error whereby the
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caller may optionally want to issue the message. */
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if (gdberrmsg != NULL)
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{
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if (exception.message != NULL)
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*gdberrmsg = xstrdup (exception.message);
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else
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*gdberrmsg = NULL;
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}
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return exception.reason;
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}
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return val;
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}
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/* This function is superseded by catch_exceptions(). */
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int
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catch_errors (catch_errors_ftype *func, void *func_args, char *errstring,
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return_mask mask)
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{
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volatile int val = 0;
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volatile struct gdb_exception exception;
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TRY_CATCH (exception, mask)
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{
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val = func (func_args);
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}
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print_any_exception (gdb_stderr, errstring, exception);
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if (exception.reason != 0)
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return 0;
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return val;
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}
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int
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catch_command_errors (catch_command_errors_ftype * command,
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char *arg, int from_tty, return_mask mask)
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{
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volatile struct gdb_exception e;
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TRY_CATCH (e, mask)
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{
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command (arg, from_tty);
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}
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print_any_exception (gdb_stderr, NULL, e);
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if (e.reason < 0)
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return 0;
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return 1;
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}
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