Target interface for reverse debugging.
* target.h (enum target_waitkind):
Add new wait event, TARGET_WAITKIND_NO_HISTORY.
(struct target_ops): New method to_can_execute_reverse.
(target_can_execute_reverse): New macro.
* target.c (update_current_target): Inherit to_can_execute_reverse.
Remote interface for reverse debugging.
* remote.c (remote_can_execute_reverse): New target method.
(remote_resume): Check for reverse exec direction, and send
appropriate command to target.
(remote_wait_as): Check target response for NO_HISTORY status.
Also check for empty reply (target doesn't understand "bs" or "bc).
(remote_vcont_resume): Jump out if attempting reverse execution.
Event handling interface for reverse debugging.
* infrun.c (execution_direction): New state variable.
(enum inferior_stop_reason): Add NO_HISTORY reason.
(handle_inferior_event): Handle TARGET_WAITKIND_NO_HISTORY.
Handle stepping over a function call in reverse.
Handle stepping thru a line range in reverse.
Handle setting a step-resume breakpoint in reverse.
Handle stepping into a function in reverse.
Handle stepping between line ranges in reverse.
(print_stop_reason): Print reason for NO_HISTORY.
(step_into_function): Rename to handle_step_into_function.
(handle_step_into_function_backward): New function.
(set_exec_direction_func, show_exec_direction_func): New funcs.
(proceed): No need to singlestep over a breakpoint
when resuming in reverse.
* inferior.h (enum exec_direction_kind): New enum.
(execution_direction): Export new execution state variable.
* breakpoint.c (make_breakpoint_silent): New function.
* breakpoint.h (make_breakpoint_silent): Export.
* infcmd.c (finish_command): Check for reverse exec direction.
(finish_backward): New function, handle finish cmd in reverse.
User interface for reverse execution.
* Makefile.in (reverse.c): New file.
* reverse.c: New file. User interface for reverse execution.
