target: Add a debug_reason command

This allows programmatically determining the debug reason.

Change-Id: I0c3e85cebb6dc28fc0fc212beca84a484ac654a5
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7952
Reviewed-by: Jan Matyas <jan.matyas@codasip.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

doc/openocd.texi

@@ -5296,6 +5296,18 @@ Displays the current target state:
 (Also, @pxref{eventpolling,,Event Polling}.)
 @end deffn
 
+@deffn {Command} {$target_name debug_reason}
+Displays the current debug reason:
+@code{debug-request},
+@code{breakpoint},
+@code{watchpoint},
+@code{watchpoint-and-breakpoint},
+@code{single-step},
+@code{target-not-halted},
+@code{program-exit},
+@code{exception-catch} or @code{undefined}.
+@end deffn
+
 @deffn {Command} {$target_name eventlist}
 Displays a table listing all event handlers
 currently associated with this target.

src/target/target.c

@@ -5874,6 +5874,18 @@ COMMAND_HANDLER(handle_target_current_state)
 	return ERROR_OK;
 }
 
+COMMAND_HANDLER(handle_target_debug_reason)
+{
+	if (CMD_ARGC != 0)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	struct target *target = get_current_target(CMD_CTX);
+
+	command_print(CMD, "%s", debug_reason_name(target));
+
+	return ERROR_OK;
+}
+
 static int jim_target_invoke_event(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
 	struct jim_getopt_info goi;
@@ -6025,6 +6037,13 @@ static const struct command_registration target_instance_command_handlers[] = {
 		.help = "displays the current state of this target",
 		.usage = "",
 	},
+	{
+		.name = "debug_reason",
+		.mode = COMMAND_EXEC,
+		.handler = handle_target_debug_reason,
+		.help = "displays the debug reason of this target",
+		.usage = "",
+	},
 	{
 		.name = "arp_examine",
 		.mode = COMMAND_EXEC,