1 /* General GDB/Guile code.
3 Copyright (C) 2014-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 /* See README file in this directory for implementation notes, coding
21 conventions, et.al. */
24 #include "breakpoint.h"
25 #include "cli/cli-cmds.h"
26 #include "cli/cli-script.h"
27 #include "cli/cli-utils.h"
31 #include "extension-priv.h"
36 #include "guile-internal.h"
40 /* The Guile version we're using.
41 We *could* use the macros in libguile/version.h but that would preclude
42 handling the user switching in a different version with, e.g.,
43 LD_LIBRARY_PATH (using a different version than what gdb was compiled with
44 is not something to be done lightly, but can be useful). */
45 int gdbscm_guile_major_version;
46 int gdbscm_guile_minor_version;
47 int gdbscm_guile_micro_version;
49 /* The guile subdirectory within gdb's data-directory. */
50 static const char *guile_datadir;
52 /* Declared constants and enum for guile exception printing. */
53 const char gdbscm_print_excp_none[] = "none";
54 const char gdbscm_print_excp_full[] = "full";
55 const char gdbscm_print_excp_message[] = "message";
57 /* "set guile print-stack" choices. */
58 static const char *const guile_print_excp_enums[] =
60 gdbscm_print_excp_none,
61 gdbscm_print_excp_full,
62 gdbscm_print_excp_message,
66 /* The exception printing variable. 'full' if we want to print the
67 error message and stack, 'none' if we want to print nothing, and
68 'message' if we only want to print the error message. 'message' is
70 const char *gdbscm_print_excp = gdbscm_print_excp_message;
73 /* Forward decls, these are defined later. */
74 extern const struct extension_language_script_ops guile_extension_script_ops;
75 extern const struct extension_language_ops guile_extension_ops;
78 /* The main struct describing GDB's interface to the Guile
79 extension language. */
80 extern const struct extension_language_defn extension_language_guile =
92 &guile_extension_script_ops,
102 static void gdbscm_finish_initialization
103 (const struct extension_language_defn *);
104 static int gdbscm_initialized (const struct extension_language_defn *);
105 static void gdbscm_eval_from_control_command
106 (const struct extension_language_defn *, struct command_line *);
107 static script_sourcer_func gdbscm_source_script;
109 int gdb_scheme_initialized;
111 /* Symbol for setting documentation strings. */
112 SCM gdbscm_documentation_symbol;
114 /* Keywords used by various functions. */
115 static SCM from_tty_keyword;
116 static SCM to_string_keyword;
118 /* The name of the various modules (without the surrounding parens). */
119 const char gdbscm_module_name[] = "gdb";
120 const char gdbscm_init_module_name[] = "gdb";
122 /* The name of the bootstrap file. */
123 static const char boot_scm_filename[] = "boot.scm";
125 /* The interface between gdb proper and loading of python scripts. */
127 const struct extension_language_script_ops guile_extension_script_ops =
129 gdbscm_source_script,
130 gdbscm_source_objfile_script,
131 gdbscm_execute_objfile_script,
132 gdbscm_auto_load_enabled
135 /* The interface between gdb proper and guile scripting. */
137 const struct extension_language_ops guile_extension_ops =
139 gdbscm_finish_initialization,
142 gdbscm_eval_from_control_command,
144 NULL, /* gdbscm_start_type_printers, */
145 NULL, /* gdbscm_apply_type_printers, */
146 NULL, /* gdbscm_free_type_printers, */
148 gdbscm_apply_val_pretty_printer,
150 NULL, /* gdbscm_apply_frame_filter, */
152 gdbscm_preserve_values,
154 gdbscm_breakpoint_has_cond,
155 gdbscm_breakpoint_cond_says_stop,
157 NULL, /* gdbscm_check_quit_flag, */
158 NULL, /* gdbscm_set_quit_flag, */
161 /* Implementation of the gdb "guile-repl" command. */
164 guile_repl_command (char *arg, int from_tty)
166 scoped_restore restore_async = make_scoped_restore (¤t_ui->async, 0);
168 arg = skip_spaces (arg);
170 /* This explicitly rejects any arguments for now.
171 "It is easier to relax a restriction than impose one after the fact."
172 We would *like* to be able to pass arguments to the interactive shell
173 but that's not what python-interactive does. Until there is time to
174 sort it out, we forbid arguments. */
177 error (_("guile-repl currently does not take any arguments."));
181 gdbscm_enter_repl ();
185 /* Implementation of the gdb "guile" command.
186 Note: Contrary to the Python version this displays the result.
187 Have to see which is better.
189 TODO: Add the result to Guile's history? */
192 guile_command (char *arg, int from_tty)
194 scoped_restore restore_async = make_scoped_restore (¤t_ui->async, 0);
196 arg = skip_spaces (arg);
200 char *msg = gdbscm_safe_eval_string (arg, 1);
204 /* It is ok that this is a "dangling cleanup" because we
205 throw immediately. */
206 make_cleanup (xfree, msg);
212 command_line_up l = get_command_line (guile_control, "");
214 execute_control_command_untraced (l.get ());
218 /* Given a command_line, return a command string suitable for passing
219 to Guile. Lines in the string are separated by newlines. The return
220 value is allocated using xmalloc and the caller is responsible for
224 compute_scheme_string (struct command_line *l)
226 struct command_line *iter;
231 for (iter = l; iter; iter = iter->next)
232 size += strlen (iter->line) + 1;
234 script = (char *) xmalloc (size + 1);
236 for (iter = l; iter; iter = iter->next)
238 int len = strlen (iter->line);
240 strcpy (&script[here], iter->line);
242 script[here++] = '\n';
248 /* Take a command line structure representing a "guile" command, and
249 evaluate its body using the Guile interpreter.
250 This is the extension_language_ops.eval_from_control_command "method". */
253 gdbscm_eval_from_control_command
254 (const struct extension_language_defn *extlang, struct command_line *cmd)
257 struct cleanup *cleanup;
259 if (cmd->body_count != 1)
260 error (_("Invalid \"guile\" block structure."));
262 cleanup = make_cleanup (null_cleanup, NULL);
264 script = compute_scheme_string (cmd->body_list[0]);
265 msg = gdbscm_safe_eval_string (script, 0);
269 make_cleanup (xfree, msg);
273 do_cleanups (cleanup);
276 /* Read a file as Scheme code.
277 This is the extension_language_script_ops.script_sourcer "method".
278 FILE is the file to run. FILENAME is name of the file FILE.
279 This does not throw any errors. If an exception occurs an error message
283 gdbscm_source_script (const struct extension_language_defn *extlang,
284 FILE *file, const char *filename)
286 char *msg = gdbscm_safe_source_script (filename);
290 fprintf_filtered (gdb_stderr, "%s\n", msg);
295 /* (execute string [#:from-tty boolean] [#:to-string boolean])
296 A Scheme function which evaluates a string using the gdb CLI. */
299 gdbscm_execute_gdb_command (SCM command_scm, SCM rest)
301 int from_tty_arg_pos = -1, to_string_arg_pos = -1;
302 int from_tty = 0, to_string = 0;
303 const SCM keywords[] = { from_tty_keyword, to_string_keyword, SCM_BOOL_F };
305 struct cleanup *cleanups;
306 struct gdb_exception except = exception_none;
308 gdbscm_parse_function_args (FUNC_NAME, SCM_ARG1, keywords, "s#tt",
309 command_scm, &command, rest,
310 &from_tty_arg_pos, &from_tty,
311 &to_string_arg_pos, &to_string);
313 /* Note: The contents of "command" may get modified while it is
315 cleanups = make_cleanup (xfree, command);
317 std::string to_string_res;
321 scoped_restore restore_async = make_scoped_restore (¤t_ui->async,
324 scoped_restore preventer = prevent_dont_repeat ();
326 to_string_res = execute_command_to_string (command, from_tty);
328 execute_command (command, from_tty);
330 /* Do any commands attached to breakpoint we stopped at. */
331 bpstat_do_actions ();
333 CATCH (ex, RETURN_MASK_ALL)
339 do_cleanups (cleanups);
340 GDBSCM_HANDLE_GDB_EXCEPTION (except);
343 return gdbscm_scm_from_c_string (to_string_res.c_str ());
344 return SCM_UNSPECIFIED;
347 /* (data-directory) -> string */
350 gdbscm_data_directory (void)
352 return gdbscm_scm_from_c_string (gdb_datadir);
355 /* (guile-data-directory) -> string */
358 gdbscm_guile_data_directory (void)
360 return gdbscm_scm_from_c_string (guile_datadir);
363 /* (gdb-version) -> string */
366 gdbscm_gdb_version (void)
368 return gdbscm_scm_from_c_string (version);
371 /* (host-config) -> string */
374 gdbscm_host_config (void)
376 return gdbscm_scm_from_c_string (host_name);
379 /* (target-config) -> string */
382 gdbscm_target_config (void)
384 return gdbscm_scm_from_c_string (target_name);
387 #else /* ! HAVE_GUILE */
389 /* Dummy implementation of the gdb "guile-repl" and "guile"
393 guile_repl_command (char *arg, int from_tty)
395 arg = skip_spaces (arg);
397 error (_("guile-repl currently does not take any arguments."));
398 error (_("Guile scripting is not supported in this copy of GDB."));
402 guile_command (char *arg, int from_tty)
404 arg = skip_spaces (arg);
406 error (_("Guile scripting is not supported in this copy of GDB."));
409 /* Even if Guile isn't enabled, we still have to slurp the
410 command list to the corresponding "end". */
411 command_line_up l = get_command_line (guile_control, "");
413 execute_control_command_untraced (l.get ());
417 #endif /* ! HAVE_GUILE */
419 /* Lists for 'set,show,info guile' commands. */
421 static struct cmd_list_element *set_guile_list;
422 static struct cmd_list_element *show_guile_list;
423 static struct cmd_list_element *info_guile_list;
425 /* Function for use by 'set guile' prefix command. */
428 set_guile_command (const char *args, int from_tty)
430 help_list (set_guile_list, "set guile ", all_commands, gdb_stdout);
433 /* Function for use by 'show guile' prefix command. */
436 show_guile_command (const char *args, int from_tty)
438 cmd_show_list (show_guile_list, from_tty, "");
441 /* The "info scheme" command is defined as a prefix, with
442 allow_unknown 0. Therefore, its own definition is called only for
443 "info scheme" with no args. */
446 info_guile_command (const char *args, int from_tty)
448 printf_unfiltered (_("\"info guile\" must be followed"
449 " by the name of an info command.\n"));
450 help_list (info_guile_list, "info guile ", all_commands, gdb_stdout);
453 /* Initialization. */
457 static const scheme_function misc_guile_functions[] =
459 { "execute", 1, 0, 1, as_a_scm_t_subr (gdbscm_execute_gdb_command),
461 Execute the given GDB command.\n\
463 Arguments: string [#:to-string boolean] [#:from-tty boolean]\n\
464 If #:from-tty is true then the command executes as if entered\n\
465 from the keyboard. The default is false (#f).\n\
466 If #:to-string is true then the result is returned as a string.\n\
467 Otherwise output is sent to the current output port,\n\
468 which is the default.\n\
469 Returns: The result of the command if #:to-string is true.\n\
470 Otherwise returns unspecified." },
472 { "data-directory", 0, 0, 0, as_a_scm_t_subr (gdbscm_data_directory),
474 Return the name of GDB's data directory." },
476 { "guile-data-directory", 0, 0, 0,
477 as_a_scm_t_subr (gdbscm_guile_data_directory),
479 Return the name of the Guile directory within GDB's data directory." },
481 { "gdb-version", 0, 0, 0, as_a_scm_t_subr (gdbscm_gdb_version),
483 Return GDB's version string." },
485 { "host-config", 0, 0, 0, as_a_scm_t_subr (gdbscm_host_config),
487 Return the name of the host configuration." },
489 { "target-config", 0, 0, 0, as_a_scm_t_subr (gdbscm_target_config),
491 Return the name of the target configuration." },
496 /* Load BOOT_SCM_FILE, the first Scheme file that gets loaded. */
499 boot_guile_support (void *boot_scm_file)
501 /* Load boot.scm without compiling it (there's no need to compile it).
502 The other files should have been compiled already, and boot.scm is
503 expected to adjust '%load-compiled-path' accordingly. If they haven't
504 been compiled, Guile will auto-compile them. The important thing to keep
505 in mind is that there's a >= 100x speed difference between compiled and
506 non-compiled files. */
507 return scm_c_primitive_load ((const char *) boot_scm_file);
510 /* Return non-zero if ARGS has the "standard" format for throw args.
511 The standard format is:
512 (function format-string (format-string-args-list) ...).
513 FUNCTION is #f if no function was recorded. */
516 standard_throw_args_p (SCM args)
518 if (gdbscm_is_true (scm_list_p (args))
519 && scm_ilength (args) >= 3)
521 /* The function in which the error occurred. */
522 SCM arg0 = scm_list_ref (args, scm_from_int (0));
523 /* The format string. */
524 SCM arg1 = scm_list_ref (args, scm_from_int (1));
525 /* The arguments of the format string. */
526 SCM arg2 = scm_list_ref (args, scm_from_int (2));
528 if ((scm_is_string (arg0) || gdbscm_is_false (arg0))
529 && scm_is_string (arg1)
530 && gdbscm_is_true (scm_list_p (arg2)))
537 /* Print the error recorded in a "standard" throw args. */
540 print_standard_throw_error (SCM args)
542 /* The function in which the error occurred. */
543 SCM arg0 = scm_list_ref (args, scm_from_int (0));
544 /* The format string. */
545 SCM arg1 = scm_list_ref (args, scm_from_int (1));
546 /* The arguments of the format string. */
547 SCM arg2 = scm_list_ref (args, scm_from_int (2));
549 /* ARG0 is #f if no function was recorded. */
550 if (gdbscm_is_true (arg0))
552 scm_simple_format (scm_current_error_port (),
553 scm_from_latin1_string (_("Error in function ~s:~%")),
556 scm_simple_format (scm_current_error_port (), arg1, arg2);
559 /* Print the error message recorded in KEY, ARGS, the arguments to throw.
560 Normally we let Scheme print the error message.
561 This function is used when Scheme initialization fails.
562 We can still use the Scheme C API though. */
565 print_throw_error (SCM key, SCM args)
567 /* IWBN to call gdbscm_print_exception_with_stack here, but Guile didn't
568 boot successfully so play it safe and avoid it. The "format string" and
569 its args are embedded in ARGS, but the content of ARGS depends on KEY.
570 Make sure ARGS has the expected canonical content before trying to use
572 if (standard_throw_args_p (args))
573 print_standard_throw_error (args);
576 scm_simple_format (scm_current_error_port (),
577 scm_from_latin1_string (_("Throw to key `~a' with args `~s'.~%")),
578 scm_list_2 (key, args));
582 /* Handle an exception thrown while loading BOOT_SCM_FILE. */
585 handle_boot_error (void *boot_scm_file, SCM key, SCM args)
587 fprintf_unfiltered (gdb_stderr, ("Exception caught while booting Guile.\n"));
589 print_throw_error (key, args);
591 fprintf_unfiltered (gdb_stderr, "\n");
592 warning (_("Could not complete Guile gdb module initialization from:\n"
594 "Limited Guile support is available.\n"
595 "Suggest passing --data-directory=/path/to/gdb/data-directory.\n"),
596 (const char *) boot_scm_file);
598 return SCM_UNSPECIFIED;
601 /* Load gdb/boot.scm, the Scheme side of GDB/Guile support.
602 Note: This function assumes it's called within the gdb module. */
605 initialize_scheme_side (void)
610 guile_datadir = concat (gdb_datadir, SLASH_STRING, "guile", (char *) NULL);
611 boot_scm_path = concat (guile_datadir, SLASH_STRING, "gdb",
612 SLASH_STRING, boot_scm_filename, (char *) NULL);
614 scm_c_catch (SCM_BOOL_T, boot_guile_support, boot_scm_path,
615 handle_boot_error, boot_scm_path, NULL, NULL);
617 xfree (boot_scm_path);
620 /* Install the gdb scheme module.
621 The result is a boolean indicating success.
622 If initializing the gdb module fails an error message is printed.
623 Note: This function runs in the context of the gdb module. */
626 initialize_gdb_module (void *data)
628 /* Computing these is a pain, so only do it once.
629 Also, do it here and save the result so that obtaining the values
631 gdbscm_guile_major_version = gdbscm_scm_string_to_int (scm_major_version ());
632 gdbscm_guile_minor_version = gdbscm_scm_string_to_int (scm_minor_version ());
633 gdbscm_guile_micro_version = gdbscm_scm_string_to_int (scm_micro_version ());
635 /* The documentation symbol needs to be defined before any calls to
636 gdbscm_define_{variables,functions}. */
637 gdbscm_documentation_symbol = scm_from_latin1_symbol ("documentation");
639 /* The smob and exception support must be initialized early. */
640 gdbscm_initialize_smobs ();
641 gdbscm_initialize_exceptions ();
643 /* The rest are initialized in alphabetical order. */
644 gdbscm_initialize_arches ();
645 gdbscm_initialize_auto_load ();
646 gdbscm_initialize_blocks ();
647 gdbscm_initialize_breakpoints ();
648 gdbscm_initialize_commands ();
649 gdbscm_initialize_disasm ();
650 gdbscm_initialize_frames ();
651 gdbscm_initialize_iterators ();
652 gdbscm_initialize_lazy_strings ();
653 gdbscm_initialize_math ();
654 gdbscm_initialize_objfiles ();
655 gdbscm_initialize_parameters ();
656 gdbscm_initialize_ports ();
657 gdbscm_initialize_pretty_printers ();
658 gdbscm_initialize_pspaces ();
659 gdbscm_initialize_strings ();
660 gdbscm_initialize_symbols ();
661 gdbscm_initialize_symtabs ();
662 gdbscm_initialize_types ();
663 gdbscm_initialize_values ();
665 gdbscm_define_functions (misc_guile_functions, 1);
667 from_tty_keyword = scm_from_latin1_keyword ("from-tty");
668 to_string_keyword = scm_from_latin1_keyword ("to-string");
670 initialize_scheme_side ();
672 gdb_scheme_initialized = 1;
675 /* Utility to call scm_c_define_module+initialize_gdb_module from
676 within scm_with_guile. */
679 call_initialize_gdb_module (void *data)
681 /* Most of the initialization is done by initialize_gdb_module.
682 It is called via scm_c_define_module so that the initialization is
683 performed within the desired module. */
684 scm_c_define_module (gdbscm_module_name, initialize_gdb_module, NULL);
686 #if HAVE_GUILE_MANUAL_FINALIZATION
687 scm_run_finalizers ();
693 /* A callback to finish Guile initialization after gdb has finished all its
695 This is the extension_language_ops.finish_initialization "method". */
698 gdbscm_finish_initialization (const struct extension_language_defn *extlang)
700 /* Restore the environment to the user interaction one. */
701 scm_set_current_module (scm_interaction_environment ());
704 /* The extension_language_ops.initialized "method". */
707 gdbscm_initialized (const struct extension_language_defn *extlang)
709 return gdb_scheme_initialized;
712 /* Enable or disable Guile backtraces. */
715 gdbscm_set_backtrace (int enable)
717 static const char disable_bt[] = "(debug-disable 'backtrace)";
718 static const char enable_bt[] = "(debug-enable 'backtrace)";
721 gdbscm_safe_eval_string (enable_bt, 0);
723 gdbscm_safe_eval_string (disable_bt, 0);
726 #endif /* HAVE_GUILE */
728 /* Install the various gdb commands used by Guile. */
731 install_gdb_commands (void)
733 add_com ("guile-repl", class_obscure,
737 Start an interactive Guile prompt.\n\
739 To return to GDB, type the EOF character (e.g., Ctrl-D on an empty\n\
741 #else /* HAVE_GUILE */
743 Start a Guile interactive prompt.\n\
745 Guile scripting is not supported in this copy of GDB.\n\
746 This command is only a placeholder.")
747 #endif /* HAVE_GUILE */
749 add_com_alias ("gr", "guile-repl", class_obscure, 1);
751 /* Since "help guile" is easy to type, and intuitive, we add general help
752 in using GDB+Guile to this command. */
753 add_com ("guile", class_obscure, guile_command,
756 Evaluate one or more Guile expressions.\n\
758 The expression(s) can be given as an argument, for instance:\n\
760 guile (display 23)\n\
762 The result of evaluating the last expression is printed.\n\
764 If no argument is given, the following lines are read and passed\n\
765 to Guile for evaluation. Type a line containing \"end\" to indicate\n\
766 the end of the set of expressions.\n\
768 The Guile GDB module must first be imported before it can be used.\n\
770 (gdb) guile (use-modules (gdb))\n\
771 or if you want to import the (gdb) module with a prefix, use:\n\
772 (gdb) guile (use-modules ((gdb) #:renamer (symbol-prefix-proc 'gdb:)))\n\
774 The Guile interactive session, started with the \"guile-repl\"\n\
775 command, provides extensive help and apropos capabilities.\n\
776 Type \",help\" once in a Guile interactive session.")
777 #else /* HAVE_GUILE */
779 Evaluate a Guile expression.\n\
781 Guile scripting is not supported in this copy of GDB.\n\
782 This command is only a placeholder.")
783 #endif /* HAVE_GUILE */
785 add_com_alias ("gu", "guile", class_obscure, 1);
787 add_prefix_cmd ("guile", class_obscure, set_guile_command,
788 _("Prefix command for Guile preference settings."),
789 &set_guile_list, "set guile ", 0,
791 add_alias_cmd ("gu", "guile", class_obscure, 1, &setlist);
793 add_prefix_cmd ("guile", class_obscure, show_guile_command,
794 _("Prefix command for Guile preference settings."),
795 &show_guile_list, "show guile ", 0,
797 add_alias_cmd ("gu", "guile", class_obscure, 1, &showlist);
799 add_prefix_cmd ("guile", class_obscure, info_guile_command,
800 _("Prefix command for Guile info displays."),
801 &info_guile_list, "info guile ", 0,
803 add_info_alias ("gu", "guile", 1);
805 /* The name "print-stack" is carried over from Python.
806 A better name is "print-exception". */
807 add_setshow_enum_cmd ("print-stack", no_class, guile_print_excp_enums,
808 &gdbscm_print_excp, _("\
809 Set mode for Guile exception printing on error."), _("\
810 Show the mode of Guile exception printing on error."), _("\
811 none == no stack or message will be printed.\n\
812 full == a message and a stack will be printed.\n\
813 message == an error message without a stack will be printed."),
815 &set_guile_list, &show_guile_list);
819 _initialize_guile (void)
821 install_gdb_commands ();
825 #ifdef HAVE_SIGPROCMASK
826 sigset_t sigchld_mask, prev_mask;
829 /* The Python support puts the C side in module "_gdb", leaving the Python
830 side to define module "gdb" which imports "_gdb". There is evidently no
831 similar convention in Guile so we skip this. */
833 #if HAVE_GUILE_MANUAL_FINALIZATION
834 /* Our SMOB free functions are not thread-safe, as GDB itself is not
835 intended to be thread-safe. Disable automatic finalization so that
836 finalizers aren't run in other threads. */
837 scm_set_automatic_finalization_enabled (0);
840 #ifdef HAVE_SIGPROCMASK
841 /* Before we initialize Guile, block SIGCHLD.
842 This is done so that all threads created during Guile initialization
843 have SIGCHLD blocked. PR 17247.
844 Really libgc and Guile should do this, but we need to work with
846 sigemptyset (&sigchld_mask);
847 sigaddset (&sigchld_mask, SIGCHLD);
848 sigprocmask (SIG_BLOCK, &sigchld_mask, &prev_mask);
851 /* scm_with_guile is the most portable way to initialize Guile.
852 Plus we need to initialize the Guile support while in Guile mode
853 (e.g., called from within a call to scm_with_guile). */
854 scm_with_guile (call_initialize_gdb_module, NULL);
856 #ifdef HAVE_SIGPROCMASK
857 sigprocmask (SIG_SETMASK, &prev_mask, NULL);
860 /* Set Guile's backtrace to match the "set guile print-stack" default.
861 [N.B. The two settings are still separate.]
862 But only do this after we've initialized Guile, it's nice to see a
863 backtrace if there's an error during initialization.
864 OTOH, if the error is that gdb/init.scm wasn't found because gdb is
865 being run from the build tree, the backtrace is more noise than signal.
867 gdbscm_set_backtrace (0);