PR gdb/13860 - Make MI sync vs async output (closer to) the same.

Ignoring expected and desired differences like whether the prompt is
output after *stoppped records, GDB MI output is still different in
sync and async modes.

In sync mode, when a CLI execution command is entered, the "reason"
field is missing in the *stopped async record.  And in async mode, for
some events, like program exits, the corresponding CLI output is
missing in the CLI channel.

Vis, diff between sync vs async modes:

   run
   ^running
   *running,thread-id="1"
   (gdb)
   ...
 - ~"[Inferior 1 (process 15882) exited normally]\n"
   =thread-exited,id="1",group-id="i1"
   =thread-group-exited,id="i1",exit-code="0"
 - *stopped
 + *stopped,reason="exited-normally"

   si
   ...
   (gdb)
   ~"0x000000000045e033\t29\t  memset (&args, 0, sizeof args);\n"
 - *stopped,frame=...,thread-id="1",stopped-threads="all",core="0"
 + *stopped,reason="end-stepping-range",frame=...,thread-id="1",stopped-threads="all",core="0"
   (gdb)

In addition, in both cases, when a MI execution command is entered,
and a breakpoint triggers, the event is sent to the console too.  But
some events like program exits have the CLI output missing in the CLI
channel:

   -exec-run
   ^running
   *running,thread-id="1"
   (gdb)
   ...
   =thread-exited,id="1",group-id="i1"
   =thread-group-exited,id="i1",exit-code="0"
 - *stopped
 + *stopped,reason="exited-normally"

We'll want to make background commands always possible by default.
IOW, make target-async be the default.  But, in order to do that,
we'll need to emulate MI sync on top of an async target.  That means
we'll have yet another combination to care for in the testsuite.

Rather than making the testsuite cope with all these differences, I
thought it better to just fix GDB to always have the complete output,
no matter whether it's in sync or async mode.

This is all related to interpreter-exec, and the corresponding uiout
switching.  (Typing a CLI command directly in MI is shorthand for
running it through -interpreter-exec console.)

In sync mode, when a CLI command is active, normal_stop is called when
the current interpreter and uiout are CLI's.  So print_XXX_reason
prints the stop reason to CLI uiout (only), and we don't show it in
MI.

In async mode the stop event is processed when we're back in the MI
interpreter, so the stop reason is printed directly to the MI uiout.

Fix this by making run control event printing roughly independent of
whatever is the current interpreter or uiout.  That is, move these
prints to interpreter observers, that know whether to print or be
quiet, and if printing, which uiout to print to.  In the case of the
console/tui interpreters, only print if the top interpreter.  For MI,
always print.

Breakpoint hits / normal stops are already handled similarly -- MI has
a normal_stop observer that prints the event to both MI and the CLI,
though that could be cleaned up further in the direction of this
patch.

This also makes all of:

 (gdb) foo
and
 (gdb) interpreter-exec MI "-exec-foo"
and
 (gdb)
 -exec-foo
and
 (gdb)
 -interpreter-exec console "foo"

print as expected.

Tested on x86_64 Fedora 20, sync and async modes.

gdb/
2014-05-29  Pedro Alves  <palves@redhat.com>

	PR gdb/13860
	* cli/cli-interp.c: Include infrun.h and observer.h.
	(cli_uiout, cli_interp): New globals.
	(cli_on_signal_received, cli_on_end_stepping_range)
	(cli_on_signal_exited, cli_on_exited, cli_on_no_history): New
	functions.
	(cli_interpreter_init): Install them as 'end_stepping_range',
	'signal_received' 'signal_exited', 'exited' and 'no_history'
	observers.
	(_initialize_cli_interp): Remove cli_interp local.
	* infrun.c (handle_inferior_event): Call the several stop reason
	observers instead of printing the stop reason directly.
	(end_stepping_range): New function.
	(print_end_stepping_range_reason, print_signal_exited_reason)
	(print_exited_reason, print_signal_received_reason)
	(print_no_history_reason): Make static, and add an uiout
	parameter.  Print to that instead of to CURRENT_UIOUT.
	* infrun.h (print_end_stepping_range_reason)
	(print_signal_exited_reason, print_exited_reason)
	(print_signal_received_reason print_no_history_reason): New
	declarations.
	* mi/mi-common.h (struct mi_interp): Rename 'uiout' field to
	'mi_uiout'.
	<cli_uiout>: New field.
	* mi/mi-interp.c (mi_interpreter_init): Adjust.  Create the new
	uiout for CLI output.  Install 'signal_received',
	'end_stepping_range', 'signal_exited', 'exited' and 'no_history'
	observers.
	(find_mi_interpreter, mi_interp_data, mi_on_signal_received)
	(mi_on_end_stepping_range, mi_on_signal_exited, mi_on_exited)
	(mi_on_no_history): New functions.
	(ui_out_free_cleanup): Delete function.
	(mi_on_normal_stop): Don't allocate a new uiout for CLI output,
	instead use the one already stored in the MI interpreter data.
	(mi_ui_out): Adjust.
	* tui/tui-interp.c: Include infrun.h and observer.h.
	(tui_interp): New global.
	(tui_on_signal_received, tui_on_end_stepping_range)
	(tui_on_signal_exited, tui_on_exited)
	(tui_on_no_history): New functions.
	(tui_init): Install them as 'end_stepping_range',
	'signal_received' 'signal_exited', 'exited' and 'no_history'
	observers.
	(_initialize_tui_interp): Delete tui_interp local.

gdb/doc/
2014-05-29  Pedro Alves  <palves@redhat.com>

	PR gdb/13860
	* observer.texi (signal_received, end_stepping_range)
	(signal_exited, exited, no_history): New observer subjects.

gdb/testsuite/
2014-05-29  Pedro Alves  <palves@redhat.com>

	PR gdb/13860
	* gdb.mi/mi-cli.exp: Always expect "end-stepping-range" stop
	reason, even in sync mode.

1 files changed, 61 insertions, 3 deletions

diff --git a/gdb/cli/cli-interp.c b/gdb/cli/cli-interp.c
index d80ee58..d3badcd 100644
--- a/gdb/cli/cli-interp.c
+++ b/gdb/cli/cli-interp.c
@@ -25,21 +25,80 @@
 #include "top.h"		/* for "execute_command" */
 #include <string.h>
 #include "exceptions.h"
-
-struct ui_out *cli_uiout;
+#include "infrun.h"
+#include "observer.h"
 
 /* These are the ui_out and the interpreter for the console
    interpreter.  */
+struct ui_out *cli_uiout;
+static struct interp *cli_interp;
 
 /* Longjmp-safe wrapper for "execute_command".  */
 static struct gdb_exception safe_execute_command (struct ui_out *uiout,
 						  char *command, 
 						  int from_tty);
+
+/* Observers for several run control events.  If the interpreter is
+   quiet (i.e., another interpreter is being run with
+   interpreter-exec), print nothing.  */
+
+/* Observer for the signal_received notification.  */
+
+static void
+cli_on_signal_received (enum gdb_signal siggnal)
+{
+  if (!interp_quiet_p (cli_interp))
+    print_signal_received_reason (cli_uiout, siggnal);
+}
+
+/* Observer for the end_stepping_range notification.  */
+
+static void
+cli_on_end_stepping_range (void)
+{
+  if (!interp_quiet_p (cli_interp))
+    print_end_stepping_range_reason (cli_uiout);
+}
+
+/* Observer for the signalled notification.  */
+
+static void
+cli_on_signal_exited (enum gdb_signal siggnal)
+{
+  if (!interp_quiet_p (cli_interp))
+    print_signal_exited_reason (cli_uiout, siggnal);
+}
+
+/* Observer for the exited notification.  */
+
+static void
+cli_on_exited (int exitstatus)
+{
+  if (!interp_quiet_p (cli_interp))
+    print_exited_reason (cli_uiout, exitstatus);
+}
+
+/* Observer for the no_history notification.  */
+
+static void
+cli_on_no_history (void)
+{
+  if (!interp_quiet_p (cli_interp))
+    print_no_history_reason (cli_uiout);
+}
+
 /* These implement the cli out interpreter: */
 
 static void *
 cli_interpreter_init (struct interp *self, int top_level)
 {
+  /* If changing this, remember to update tui-interp.c as well.  */
+  observer_attach_end_stepping_range (cli_on_end_stepping_range);
+  observer_attach_signal_received (cli_on_signal_received);
+  observer_attach_signal_exited (cli_on_signal_exited);
+  observer_attach_exited (cli_on_exited);
+  observer_attach_no_history (cli_on_no_history);
+
   return NULL;
 }
 
@@ -155,7 +214,6 @@ _initialize_cli_interp (void)
     NULL,                       /* set_logging_proc */
     cli_command_loop            /* command_loop_proc */
   };
-  struct interp *cli_interp;
 
   /* Create a default uiout builder for the CLI.  */
   cli_uiout = cli_out_new (gdb_stdout);