Files
binutils-gdb/gdb/cli/cli-interp.c
Pedro Alves b885aea1bb Simplify interp::exec / interp_exec - let exceptions propagate
This patch implements a simplication that I suggested here:

  https://sourceware.org/pipermail/gdb-patches/2022-March/186320.html

Currently, the interp::exec virtual method interface is such that
subclass implementations must catch exceptions and then return them
via normal function return.

However, higher up the in chain, for the CLI we get to
interpreter_exec_cmd, which does:

  for (i = 1; i < nrules; i++)
    {
      struct gdb_exception e = interp_exec (interp_to_use, prules[i]);

      if (e.reason < 0)
	{
	  interp_set (old_interp, 0);
	  error (_("error in command: \"%s\"."), prules[i]);
	}
    }

and for MI we get to mi_cmd_interpreter_exec, which has:

  void
  mi_cmd_interpreter_exec (const char *command, char **argv, int argc)
  {
  ...
    for (i = 1; i < argc; i++)
      {
	struct gdb_exception e = interp_exec (interp_to_use, argv[i]);

	if (e.reason < 0)
	  error ("%s", e.what ());
      }
  }

Note that if those errors are reached, we lose the original
exception's error code.  I can't see why we'd want that.

And, I can't see why we need to have interp_exec catch the exception
and return it via the normal return path.  That's normally needed when
we need to handle propagating exceptions across C code, like across
readline or ncurses, but that's not the case here.

It seems to me that we can simplify things by removing some
try/catch-ing and just letting exceptions propagate normally.

Note, the "error in command" error shown above, which only exists in
the CLI interpreter-exec command, is only ever printed AFAICS if you
run "interpreter-exec console" when the top level interpreter is
already the console/tui.  Like:

 (gdb) interpreter-exec console "foobar"
 Undefined command: "foobar".  Try "help".
 error in command: "foobar".

You won't see it with MI's "-interpreter-exec console" from a top
level MI interpreter:

 (gdb)
 -interpreter-exec console "foobar"
 &"Undefined command: \"foobar\".  Try \"help\".\n"
 ^error,msg="Undefined command: \"foobar\".  Try \"help\"."
 (gdb)

nor with MI's "-interpreter-exec mi" from a top level MI interpreter:

 (gdb)
 -interpreter-exec mi "-foobar"
 ^error,msg="Undefined MI command: foobar",code="undefined-command"
 ^done
 (gdb)

in both these cases because MI's -interpreter-exec just does:

  error ("%s", e.what ());

You won't see it either when running an MI command with the CLI's
"interpreter-exec mi":

 (gdb) interpreter-exec mi "-foobar"
 ^error,msg="Undefined MI command: foobar",code="undefined-command"
 (gdb)

This last case is because MI's interp::exec implementation never
returns an error:

 gdb_exception
 mi_interp::exec (const char *command)
 {
   mi_execute_command_wrapper (command);
   return gdb_exception ();
 }

Thus I think that "error in command" error is pretty pointless, and
since it simplifies things to not have it, the patch just removes it.

The patch also ends up addressing an old FIXME.

Change-Id: I5a6432a80496934ac7127594c53bf5221622e393
Approved-By: Tom Tromey <tromey@adacore.com>
Approved-By: Kevin Buettner <kevinb@redhat.com>
2023-02-08 17:28:42 +00:00

440 lines
12 KiB
C

/* CLI Definitions for GDB, the GNU debugger.
Copyright (C) 2002-2023 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/>. */
#include "defs.h"
#include "cli-interp.h"
#include "interps.h"
#include "event-top.h"
#include "ui-out.h"
#include "cli-out.h"
#include "top.h" /* for "execute_command" */
#include "infrun.h"
#include "observable.h"
#include "gdbthread.h"
#include "thread-fsm.h"
#include "inferior.h"
cli_interp_base::cli_interp_base (const char *name)
: interp (name)
{}
cli_interp_base::~cli_interp_base ()
{}
/* The console interpreter. */
class cli_interp final : public cli_interp_base
{
public:
explicit cli_interp (const char *name);
~cli_interp () = default;
void init (bool top_level) override;
void resume () override;
void suspend () override;
void exec (const char *command_str) override;
ui_out *interp_ui_out () override;
private:
/* The ui_out for the console interpreter. */
std::unique_ptr<cli_ui_out> m_cli_uiout;
};
cli_interp::cli_interp (const char *name)
: cli_interp_base (name),
m_cli_uiout (new cli_ui_out (gdb_stdout))
{
}
/* Suppress notification struct. */
struct cli_suppress_notification cli_suppress_notification;
/* Returns the INTERP's data cast as cli_interp_base if INTERP is a
console-like interpreter, and returns NULL otherwise. */
static cli_interp_base *
as_cli_interp_base (interp *interp)
{
return dynamic_cast<cli_interp_base *> (interp);
}
/* See cli-interp.h.
Breakpoint hits should always be mirrored to a console. Deciding
what to mirror to a console wrt to breakpoints and random stops
gets messy real fast. E.g., say "s" trips on a breakpoint. We'd
clearly want to mirror the event to the console in this case. But
what about more complicated cases like "s&; thread n; s&", and one
of those steps spawning a new thread, and that thread hitting a
breakpoint? It's impossible in general to track whether the thread
had any relation to the commands that had been executed. So we
just simplify and always mirror breakpoints and random events to
all consoles.
OTOH, we should print the source line to the console when stepping
or other similar commands, iff the step was started by that console
(or in MI's case, by a console command), but not if it was started
with MI's -exec-step or similar. */
int
should_print_stop_to_console (struct interp *console_interp,
struct thread_info *tp)
{
if ((bpstat_what (tp->control.stop_bpstat).main_action
== BPSTAT_WHAT_STOP_NOISY)
|| tp->thread_fsm () == nullptr
|| tp->thread_fsm ()->command_interp == console_interp
|| !tp->thread_fsm ()->finished_p ())
return 1;
return 0;
}
/* Observers for several run control events. If the interpreter is
quiet (i.e., another interpreter is being run with
interpreter-exec), print nothing. These are named "cli_base" as
they print to both CLI interpreters and TUI interpreters. */
/* Observer for the normal_stop notification. */
static void
cli_base_on_normal_stop (struct bpstat *bs, int print_frame)
{
if (!print_frame)
return;
/* This event is suppressed. */
if (cli_suppress_notification.normal_stop)
return;
SWITCH_THRU_ALL_UIS ()
{
struct interp *interp = top_level_interpreter ();
cli_interp_base *cli = as_cli_interp_base (interp);
if (cli == nullptr)
continue;
thread_info *thread = inferior_thread ();
if (should_print_stop_to_console (interp, thread))
print_stop_event (cli->interp_ui_out ());
}
}
/* Observer for the signal_received notification. */
static void
cli_base_on_signal_received (enum gdb_signal siggnal)
{
SWITCH_THRU_ALL_UIS ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
continue;
print_signal_received_reason (cli->interp_ui_out (), siggnal);
}
}
/* Observer for the end_stepping_range notification. */
static void
cli_base_on_end_stepping_range ()
{
SWITCH_THRU_ALL_UIS ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
continue;
print_end_stepping_range_reason (cli->interp_ui_out ());
}
}
/* Observer for the signalled notification. */
static void
cli_base_on_signal_exited (enum gdb_signal siggnal)
{
SWITCH_THRU_ALL_UIS ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
continue;
print_signal_exited_reason (cli->interp_ui_out (), siggnal);
}
}
/* Observer for the exited notification. */
static void
cli_base_on_exited (int exitstatus)
{
SWITCH_THRU_ALL_UIS ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
continue;
print_exited_reason (cli->interp_ui_out (), exitstatus);
}
}
/* Observer for the no_history notification. */
static void
cli_base_on_no_history ()
{
SWITCH_THRU_ALL_UIS ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
continue;
print_no_history_reason (cli->interp_ui_out ());
}
}
/* Observer for the sync_execution_done notification. */
static void
cli_base_on_sync_execution_done ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
return;
display_gdb_prompt (NULL);
}
/* Observer for the command_error notification. */
static void
cli_base_on_command_error ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
return;
display_gdb_prompt (NULL);
}
/* Observer for the user_selected_context_changed notification. */
static void
cli_base_on_user_selected_context_changed (user_selected_what selection)
{
/* This event is suppressed. */
if (cli_suppress_notification.user_selected_context)
return;
thread_info *tp = inferior_ptid != null_ptid ? inferior_thread () : nullptr;
SWITCH_THRU_ALL_UIS ()
{
cli_interp_base *cli = as_cli_interp_base (top_level_interpreter ());
if (cli == nullptr)
continue;
if (selection & USER_SELECTED_INFERIOR)
print_selected_inferior (cli->interp_ui_out ());
if (tp != nullptr
&& ((selection & (USER_SELECTED_THREAD | USER_SELECTED_FRAME))))
print_selected_thread_frame (cli->interp_ui_out (), selection);
}
}
/* pre_command_loop implementation. */
void
cli_interp_base::pre_command_loop ()
{
display_gdb_prompt (0);
}
/* These implement the cli out interpreter: */
void
cli_interp::init (bool top_level)
{
}
void
cli_interp::resume ()
{
struct ui *ui = current_ui;
struct ui_file *stream;
/*sync_execution = 1; */
/* gdb_setup_readline will change gdb_stdout. If the CLI was
previously writing to gdb_stdout, then set it to the new
gdb_stdout afterwards. */
stream = m_cli_uiout->set_stream (gdb_stdout);
if (stream != gdb_stdout)
{
m_cli_uiout->set_stream (stream);
stream = NULL;
}
gdb_setup_readline (1);
ui->input_handler = command_line_handler;
if (stream != NULL)
m_cli_uiout->set_stream (gdb_stdout);
}
void
cli_interp::suspend ()
{
gdb_disable_readline ();
}
void
cli_interp::exec (const char *command_str)
{
/* gdb_stdout could change between the time m_cli_uiout was
initialized and now. Since we're probably using a different
interpreter which has a new ui_file for gdb_stdout, use that one
instead of the default.
It is important that it gets reset everytime, since the user
could set gdb to use a different interpreter. */
ui_file *old_stream = m_cli_uiout->set_stream (gdb_stdout);
SCOPE_EXIT { m_cli_uiout->set_stream (old_stream); };
/* Save and override the global ``struct ui_out'' builder. */
scoped_restore saved_uiout = make_scoped_restore (&current_uiout,
m_cli_uiout.get ());
try
{
execute_command (command_str, 1);
}
catch (const gdb_exception_error &ex)
{
exception_print (gdb_stderr, ex);
throw;
}
}
bool
cli_interp_base::supports_command_editing ()
{
return true;
}
ui_out *
cli_interp::interp_ui_out ()
{
return m_cli_uiout.get ();
}
/* See cli-interp.h. */
void
cli_interp_base::set_logging (ui_file_up logfile, bool logging_redirect,
bool debug_redirect)
{
if (logfile != nullptr)
{
gdb_assert (m_saved_output == nullptr);
m_saved_output.reset (new saved_output_files);
m_saved_output->out = gdb_stdout;
m_saved_output->err = gdb_stderr;
m_saved_output->log = gdb_stdlog;
m_saved_output->targ = gdb_stdtarg;
m_saved_output->targerr = gdb_stdtargerr;
ui_file *logfile_p = logfile.get ();
m_saved_output->logfile_holder = std::move (logfile);
/* The new stdout and stderr only depend on whether logging
redirection is being done. */
ui_file *new_stdout = logfile_p;
ui_file *new_stderr = logfile_p;
if (!logging_redirect)
{
m_saved_output->stdout_holder.reset
(new tee_file (gdb_stdout, logfile_p));
new_stdout = m_saved_output->stdout_holder.get ();
m_saved_output->stderr_holder.reset
(new tee_file (gdb_stderr, logfile_p));
new_stderr = m_saved_output->stderr_holder.get ();
}
m_saved_output->stdlog_holder.reset
(new timestamped_file (debug_redirect ? logfile_p : new_stderr));
gdb_stdout = new_stdout;
gdb_stdlog = m_saved_output->stdlog_holder.get ();
gdb_stderr = new_stderr;
gdb_stdtarg = new_stderr;
gdb_stdtargerr = new_stderr;
}
else
{
gdb_stdout = m_saved_output->out;
gdb_stderr = m_saved_output->err;
gdb_stdlog = m_saved_output->log;
gdb_stdtarg = m_saved_output->targ;
gdb_stdtargerr = m_saved_output->targerr;
m_saved_output.reset (nullptr);
}
}
/* Factory for CLI interpreters. */
static struct interp *
cli_interp_factory (const char *name)
{
return new cli_interp (name);
}
/* Standard gdb initialization hook. */
void _initialize_cli_interp ();
void
_initialize_cli_interp ()
{
interp_factory_register (INTERP_CONSOLE, cli_interp_factory);
/* Note these all work for both the CLI and TUI interpreters. */
gdb::observers::normal_stop.attach (cli_base_on_normal_stop,
"cli-interp-base");
gdb::observers::end_stepping_range.attach (cli_base_on_end_stepping_range,
"cli-interp-base");
gdb::observers::signal_received.attach (cli_base_on_signal_received,
"cli-interp-base");
gdb::observers::signal_exited.attach (cli_base_on_signal_exited,
"cli-interp-base");
gdb::observers::exited.attach (cli_base_on_exited, "cli-interp-base");
gdb::observers::no_history.attach (cli_base_on_no_history, "cli-interp-base");
gdb::observers::sync_execution_done.attach (cli_base_on_sync_execution_done,
"cli-interp-base");
gdb::observers::command_error.attach (cli_base_on_command_error,
"cli-interp-base");
gdb::observers::user_selected_context_changed.attach
(cli_base_on_user_selected_context_changed, "cli-interp-base");
}