[debugger] Fixing two crashes while debugging an Android app. (mono#13373)

* [debugger] Fixing two crashes while debugging an Android app.

-> Doing stepping into in VSM in some situation the frame saved in TLS is not synchronised with what is really been executed in the main thread. This makes the debugger-agent crashes because it tries to get variable info in some memory that is not available anymore.
	-> To fix it I forced the update of stack when CMD_THREAD_GET_FRAME_INFO is called.

-> Doing step over in Visual Studio for Windows, if you have the threads debugger window enabled, VSW calls frame_commands for each thread that is showed, and if the thread is not really_suspended it tries to get variable info from a memory that is not available anymore because the thread is not suspended yet.
	-> To fix it I don't send variable info of a frame if the thread is not really_suspended and doesn't have an async_state valid.

Cherry-picked with some light massaging by Alex Thibodeau (case 1249172)

Author: thaystg

mono/mini/debugger-agent.c

@@ -3519,7 +3519,7 @@ compute_frame_info_from (MonoInternalThread *thread, DebuggerTlsData *tls, MonoT
 }
 
 static void
-compute_frame_info (MonoInternalThread *thread, DebuggerTlsData *tls)
+compute_frame_info (MonoInternalThread *thread, DebuggerTlsData *tls, gboolean force_update)
 {
 	ComputeFramesUserData user_data;
 	GSList *tmp;
@@ -3528,7 +3528,7 @@ compute_frame_info (MonoInternalThread *thread, DebuggerTlsData *tls)
 	MonoUnwindOptions opts = (MonoUnwindOptions)(MONO_UNWIND_DEFAULT | MONO_UNWIND_REG_LOCATIONS);
 
 	// FIXME: Locking on tls
-	if (tls->frames && tls->frames_up_to_date)
+	if (tls->frames && tls->frames_up_to_date && !force_update)
 		return;
 
 	DEBUG_PRINTF (1, "Frames for %p(tid=%lx):\n", thread, thread->tid);
@@ -5211,7 +5211,7 @@ static void ss_calculate_framecount (DebuggerTlsData *tls, MonoContext *ctx)
 {
 	if (!tls->context.valid)
 		mono_thread_state_init_from_monoctx (&tls->context, ctx);
-	compute_frame_info (tls->thread, tls);
+	compute_frame_info (tls->thread, tls, FALSE);
 }
 
 static gboolean
@@ -6533,7 +6533,7 @@ ss_start (SingleStepReq *ss_req, MonoMethod *method, SeqPoint* sp, MonoSeqPointI
 			mono_loader_lock ();
 			locked = TRUE;
 
-			compute_frame_info (tls->thread, tls);
+			compute_frame_info (tls->thread, tls, FALSE);
 			frames = tls->frames;
 			nframes = tls->frame_count;
 		}
@@ -6866,7 +6866,7 @@ ss_create (MonoInternalThread *thread, StepSize size, StepDepth depth, StepFilte
 			if (frames && nframes)
 				frame = frames [0];
 		} else {
-			compute_frame_info (thread, tls);
+			compute_frame_info (thread, tls, FALSE);
 
 			if (tls->frame_count)
 				frame = tls->frames [0];
@@ -11189,7 +11189,7 @@ thread_commands (int command, guint8 *p, guint8 *end, Buffer *buf)
 		if (tls == NULL)
 			return ERR_UNLOADED;
 
-		compute_frame_info (thread, tls);
+		compute_frame_info (thread, tls, TRUE); //the last parameter is TRUE to force that the frame info that will be send is synchronised with the debugged thread
 
 		buffer_add_int (buf, tls->frame_count);
 		for (i = 0; i < tls->frame_count; ++i) {
@@ -11246,7 +11246,7 @@ thread_commands (int command, guint8 *p, guint8 *end, Buffer *buf)
 		mono_loader_unlock ();
 		g_assert (tls);
 
-		compute_frame_info (thread, tls);
+		compute_frame_info (thread, tls, FALSE);
 		if (tls->frame_count == 0 || tls->frames [0]->actual_method != method)
 			return ERR_INVALID_ARGUMENT;
 
@@ -11350,6 +11350,9 @@ frame_commands (int command, guint8 *p, guint8 *end, Buffer *buf)
 	if (i == tls->frame_count)
 		return ERR_INVALID_FRAMEID;
 
+	/* The thread is still running native code, can't get frame variables info */
+	if (!tls->really_suspended && !tls->async_state.valid) 
+		return ERR_NOT_SUSPENDED;
 	frame_idx = i;
 	frame = tls->frames [frame_idx];