gdb/mi: fix ^running record with multiple MI interpreters

I stumbled on the mi_proceeded and running_result_record_printed
globals, which are shared by all MI interpreter instances (it's unlikely
that people use multiple MI interpreter instances, but it's possible).
After poking at it, I found this bug:

1. Start GDB in MI mode
2. Add a second MI interpreter with the new-ui command
3. Use -exec-run on the second interpreter

This is the output I get on the first interpreter:

    =thread-group-added,id="i1"
    ~"Reading symbols from a.out...\n"
    ~"New UI allocated\n"
    (gdb)
    =thread-group-started,id="i1",pid="94718"
    =thread-created,id="1",group-id="i1"
    ^running
    *running,thread-id="all"

And this is the output I get on the second intepreter:

    =thread-group-added,id="i1"
    (gdb)
    -exec-run
    =thread-group-started,id="i1",pid="94718"
    =thread-created,id="1",group-id="i1"
    *running,thread-id="all"

The problem here is that the `^running` reply to the -exec-run command
is printed on the wrong UI.  It is printed on the first one, it should
be printed on the second (the one on which we sent the -exec-run).

What happens under the hood is that captured_mi_execute_command, while
executing a command for the second intepreter, clears the
running_result_record_printed and mi_proceeded globals.
mi_about_to_proceed then sets mi_proceeded.  Then, mi_on_resume_1 gets
called for the first intepreter first.  Since the

    !running_result_record_printed && mi_proceeded

condition is true, it prints a ^running, and sets
running_result_record_printed.  When mi_on_resume_1 gets called for the
second interpreter, running_result_record_printed is already set, so
^running is not printed there.

It took me a while to understand the relationship between these two
variables.  I think that in the end, this is what we want to track:

 1. When executing an MI command, take note if that command causes a
    "proceed".  This is done in mi_about_to_proceed.
 2. In mi_on_resume_1, if the command indeed caused a "proceed", we want
    to output a ^running record.  And we want to remember that we did,
    because...
 3. Back in captured_mi_execute_command, if we did not output a
    ^running, we want to output a ^done.

Moving those two variables to the mi_interp struture appears to fix it.
Only for the interpreter doing the -exec-run command does the
running_result_record_printed flag get cleared, and therefore only or
that one does the ^running record get printed.

Add a new test for this, that does pretty much what the reproducer above
shows.  Without the fix, the test fails because
mi_send_resuming_command_raw never sees the ^running record.

Change-Id: I63ea30e6cb61a8e1dd5ef03377e6003381a9209b
Tested-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>

4 files changed, 19 insertions, 17 deletions

diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index 47aeabd..d8b49ae 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -677,7 +677,12 @@ mi_about_to_proceed (void)
 	return;
     }
 
-  mi_proceeded = 1;
+  mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+  if (mi == nullptr)
+    return;
+
+  mi->mi_proceeded = 1;
 }
 
 /* When the element is non-zero, no MI notifications will be emitted in
@@ -961,7 +966,7 @@ mi_on_resume_1 (struct mi_interp *mi,
      will make it impossible for frontend to know what's going on.
 
      In future (MI3), we'll be outputting "^done" here.  */
-  if (!running_result_record_printed && mi_proceeded)
+  if (!mi->running_result_record_printed && mi->mi_proceeded)
     {
       gdb_printf (mi->raw_stdout, "%s^running\n",
 		  current_token ? current_token : "");
@@ -977,9 +982,9 @@ mi_on_resume_1 (struct mi_interp *mi,
     for (thread_info *tp : all_non_exited_threads (targ, ptid))
       mi_output_running (tp);
 
-  if (!running_result_record_printed && mi_proceeded)
+  if (!mi->running_result_record_printed && mi->mi_proceeded)
     {
-      running_result_record_printed = 1;
+      mi->running_result_record_printed = 1;
       /* This is what gdb used to do historically -- printing prompt
 	 even if it cannot actually accept any input.  This will be
 	 surely removed for MI3, and may be removed even earlier.  */
diff --git a/gdb/mi/mi-interp.h b/gdb/mi/mi-interp.h
index e07be12..eb81cbe 100644
--- a/gdb/mi/mi-interp.h
+++ b/gdb/mi/mi-interp.h
@@ -64,6 +64,12 @@ public:
 
   /* MI's CLI builder (wraps OUT).  */
   struct ui_out *cli_uiout;
+
+  int running_result_record_printed = 1;
+
+  /* Flag indicating that the target has proceeded since the last
+     command was issued.  */
+  int mi_proceeded;
 };
 
 /* Output the shared object attributes to UIOUT.  */
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 7a8c35c..dc7d717 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -84,12 +84,6 @@ char *current_token;
    command including all option, and make it possible.  */
 static struct mi_parse *current_context;
 
-int running_result_record_printed = 1;
-
-/* Flag indicating that the target has proceeded since the last
-   command was issued.  */
-int mi_proceeded;
-
 static void mi_cmd_execute (struct mi_parse *parse);
 
 static void mi_execute_async_cli_command (const char *cli_command,
@@ -1818,8 +1812,8 @@ captured_mi_execute_command (struct ui_out *uiout, struct mi_parse *context)
   scoped_restore save_token = make_scoped_restore (&current_token,
 						   context->token);
 
-  running_result_record_printed = 0;
-  mi_proceeded = 0;
+  mi->running_result_record_printed = 0;
+  mi->mi_proceeded = 0;
   switch (context->op)
     {
     case MI_COMMAND:
@@ -1837,7 +1831,7 @@ captured_mi_execute_command (struct ui_out *uiout, struct mi_parse *context)
 	 to directly use the mi_interp's uiout, since the command
 	 could have reset the interpreter, in which case the current
 	 uiout will most likely crash in the mi_out_* routines.  */
-      if (!running_result_record_printed)
+      if (!mi->running_result_record_printed)
 	{
 	  gdb_puts (context->token, mi->raw_stdout);
 	  /* There's no particularly good reason why target-connect results
@@ -1876,7 +1870,7 @@ captured_mi_execute_command (struct ui_out *uiout, struct mi_parse *context)
 	    || current_interp_named_p (INTERP_MI3)
 	    || current_interp_named_p (INTERP_MI4))
 	  {
-	    if (!running_result_record_printed)
+	    if (!mi->running_result_record_printed)
 	      {
 		gdb_puts (context->token, mi->raw_stdout);
 		gdb_puts ("^done", mi->raw_stdout);
diff --git a/gdb/mi/mi-main.h b/gdb/mi/mi-main.h
index 18687d5..1741f48 100644
--- a/gdb/mi/mi-main.h
+++ b/gdb/mi/mi-main.h
@@ -36,9 +36,6 @@ extern int mi_async_p (void);
 
 extern char *current_token;
 
-extern int running_result_record_printed;
-extern int mi_proceeded;
-
 struct mi_suppress_notification
 {
   /* Breakpoint notification suppressed?  */