Re: GDB MI Reverse Commands added [1 of 3]

Michael Snyder
2009-09-10T21:09:15Z

Maybe these questions were intended for Jakob?

Vladimir Prus wrote:
> Michael Snyder wrote:
>
>> Index: mi-main.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/mi/mi-main.c,v
>> retrieving revision 1.156
>> diff -u -p -r1.156 mi-main.c
>> --- mi-main.c 2 Jul 2009 17:25:59 -0000 1.156
>> +++ mi-main.c 27 Aug 2009 01:45:23 -0000
>> @@ -88,8 +88,8 @@ static void mi_cmd_execute (struct mi_pa
>>
>> static void mi_execute_cli_command (const char *cmd, int args_p,
>> const char *args);
>> -static void mi_execute_async_cli_command (char *cli_command,
>> - char **argv, int argc);
>> +static void mi_execute_async_cli_command (char *cli_command,
>> + char **argv, int argc);
>> static int register_changed_p (int regnum, struct regcache *,
>> struct regcache *);
>> static void get_register (struct frame_info *, int regnum, int format);
>> @@ -119,35 +119,50 @@ void
>> mi_cmd_exec_next (char *command, char **argv, int argc)
>> {
>> /* FIXME: Should call a libgdb function, not a cli wrapper. */
>> - mi_execute_async_cli_command ("next", argv, argc);
>> + if (argc > 0 && strcmp(argv[0], "--reverse") == 0)
>> + mi_execute_async_cli_command ("reverse-next", argv + 1, argc - 1);
>> + else
>> + mi_execute_async_cli_command ("next", argv, argc);
>> }
>>
>> void
>> mi_cmd_exec_next_instruction (char *command, char **argv, int argc)
>> {
>> /* FIXME: Should call a libgdb function, not a cli wrapper. */
>> - mi_execute_async_cli_command ("nexti", argv, argc);
>> + if (argc > 0 && strcmp(argv[0], "--reverse") == 0)
>> + mi_execute_async_cli_command ("reverse-nexti", argv + 1, argc - 1);
>> + else
>> + mi_execute_async_cli_command ("nexti", argv, argc);
>> }
>>
>> void
>> mi_cmd_exec_step (char *command, char **argv, int argc)
>> {
>> /* FIXME: Should call a libgdb function, not a cli wrapper. */
>> - mi_execute_async_cli_command ("step", argv, argc);
>> + if (argc > 0 && strcmp(argv[0], "--reverse") == 0)
>> + mi_execute_async_cli_command ("reverse-step", argv + 1, argc - 1);
>> + else
>> + mi_execute_async_cli_command ("step", argv, argc);
>> }
>>
>> void
>> mi_cmd_exec_step_instruction (char *command, char **argv, int argc)
>> {
>> /* FIXME: Should call a libgdb function, not a cli wrapper. */
>> - mi_execute_async_cli_command ("stepi", argv, argc);
>> + if (argc > 0 && strcmp(argv[0], "--reverse") == 0)
>> + mi_execute_async_cli_command ("reverse-stepi", argv + 1, argc - 1);
>> + else
>> + mi_execute_async_cli_command ("stepi", argv, argc);
>> }
>>
>> void
>> mi_cmd_exec_finish (char *command, char **argv, int argc)
>> {
>> /* FIXME: Should call a libgdb function, not a cli wrapper. */
>> - mi_execute_async_cli_command ("finish", argv, argc);
>> + if (argc > 0 && strcmp(argv[0], "--reverse") == 0)
>> + mi_execute_async_cli_command ("reverse-finish", argv + 1, argc - 1);
>> + else
>> + mi_execute_async_cli_command ("finish", argv, argc);
>> }
>
> What will happen if MI client does not pass --reverse, but
> execution_direction is set to reverse via CLI? It seems that this will execute
> finish in reverse? I think this is not desirable -- rather -exec-finish
> should always be forward. On the other hand, this is something that
> I probably can fix as a follow-up patch, somewhere in MI core.
>
>> void
>> @@ -175,7 +190,7 @@ mi_cmd_exec_jump (char *args, char **arg
>> /* FIXME: Should call a libgdb function, not a cli wrapper. */
>> return mi_execute_async_cli_command ("jump", argv, argc);
>> }
>> -
>> +
>
> Stray whitespace change. The patch has a few of those, I imagine
> that whoever ends up applying the patch to CVS once the copyright
> assignment is sorted can undo this damage.
>
>> static int
>> proceed_thread_callback (struct thread_info *thread, void *arg)
>> {
>> @@ -193,8 +208,8 @@ proceed_thread_callback (struct thread_i
>> return 0;
>> }
>>
>> -void
>> -mi_cmd_exec_continue (char *command, char **argv, int argc)
>> +static void
>> +exec_continue (char **argv, int argc)
>> {
>> if (argc == 0)
>> continue_1 (0);
>> @@ -212,10 +227,50 @@ mi_cmd_exec_continue (char *command, cha
>>
>> old_chain = make_cleanup_restore_current_thread ();
>> iterate_over_threads (proceed_thread_callback, &pid);
>> - do_cleanups (old_chain);
>> + do_cleanups (old_chain);
>> }
>> else
>> - error ("Usage: -exec-continue [--all|--thread-group id]");
>> + error ("Usage: -exec-continue [--reverse] [--all|--thread-group id]");
>> +}
>> +
>> +/* continue in reverse direction:
>> + XXX: code duplicated from reverse.c */
>> +
>> +static void
>> +exec_direction_default (void *notused)
>> +{
>> + /* Return execution direction to default state. */
>> + execution_direction = EXEC_FORWARD;
>> +}
>> +
>> +static void
>> +exec_reverse_continue (char **argv, int argc)
>> +{
>> + enum exec_direction_kind dir = execution_direction;
>> + struct cleanup *old_chain;
>> +
>> + if (dir == EXEC_ERROR)
>> + error (_("Target %s does not support this command."), target_shortname);
>> +
>> + if (dir == EXEC_REVERSE)
>> + error (_("Already in reverse mode."));
>> +
>> + if (!target_can_execute_reverse)
>> + error (_("Target %s does not support this command."), target_shortname);
>> +
>> + old_chain = make_cleanup (exec_direction_default, NULL);
>> + execution_direction = EXEC_REVERSE;
>> + exec_continue (argv, argc);
>> + do_cleanups (old_chain);
>> +}
>
> Why is this code "duplicated from reverse.c"? In other words, cannot
> mi_cmd_exec_continue call 'reverse_continue'? If this is not possible,
> there should be a comment explaining why.
>
> Otherwise, this is OK. Thanks!
>
> - Volodya
>
>
>