[PATCH v3 12/44] gdb, infrun, ze: allow saving process events

[Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>]

From: Markus Metzger <markus.t.metzger@intel.com>

When a process stop reply is encountered during stop_all_threads (), a new
thread with the process' ptid is created and the waitstatus is saved in
that thread.  The effect is that we have a thread with a process ptid and
we dropped the event.

Save the waitstatus in the inferior, prevent that inferior from resuming,
and return it on the next wait.
---
 gdb/inferior.h |  4 ++++
 gdb/infrun.c   | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/gdb/inferior.h b/gdb/inferior.h
index fe94e289bdc741e4763461e2df44e4153b6f5e12..ef6d236b0f72638879b33f1894fbf3d1d7050816 100644
--- a/gdb/inferior.h
+++ b/gdb/inferior.h
@@ -64,6 +64,7 @@ struct thread_info;
 #include "displaced-stepping.h"
 
 #include "gdbsupport/unordered_map.h"
+#include <optional>
 
 struct infcall_suspend_state;
 struct infcall_control_state;
@@ -326,6 +327,9 @@ struct inferior_control_state
 
   /* See the definition of stop_kind above.  */
   enum stop_kind stop_soon;
+
+  /* The waitstatus for this inferior's last event.  */
+  std::optional<target_waitstatus> waitstatus;
 };
 
 /* Initialize the inferior-related global state.  */
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 9d3e1b7782e4ddf84089156e910f77c6396586a4..4483082c899c5648f8693636ebe2af0d47da238e 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -2654,6 +2654,27 @@ resume_1 (enum gdb_signal sig)
   gdb_assert (!tp->stop_requested);
   gdb_assert (!thread_is_in_step_over_chain (tp));
 
+  inferior *inf = tp->inf;
+  process_stratum_target *target = inf->process_target ();
+  if (inf->control.waitstatus.has_value ())
+    {
+      infrun_debug_printf
+	("inferior %s has pending wait status %s.",
+	 target_pid_to_str (ptid_t (inf->pid)).c_str (),
+	 inf->control.waitstatus->to_string ().c_str ());
+
+      target->threads_executing = true;
+
+      if (target_can_async_p ())
+	{
+	  target_async (1);
+	  /* Tell the event loop we have an event to process.  */
+	  mark_async_event_handler (infrun_async_inferior_event_token);
+	}
+
+      return;
+    }
+
   if (tp->has_pending_waitstatus ())
     {
       infrun_debug_printf
@@ -4043,6 +4064,20 @@ do_target_wait_1 (inferior *inf, ptid_t ptid,
      the wait code relies on it - doing so is always a mistake.  */
   switch_to_inferior_no_thread (inf);
 
+  /* Check if we have any saved waitstatus for the inferior itself.  */
+  if (inf->control.waitstatus.has_value ())
+    {
+      /* Wake up the event loop again, until all pending events are
+	 processed.  */
+      if (target_is_async_p ())
+	mark_async_event_handler (infrun_async_inferior_event_token);
+
+      *status = *inf->control.waitstatus;
+      inf->control.waitstatus.reset ();
+
+      return ptid_t (inf->pid);
+    }
+
   /* First check if there is a resumed thread with a wait status
      pending.  */
   if (ptid == minus_one_ptid || ptid.is_pid ())
@@ -5501,6 +5536,22 @@ handle_one (const wait_one_event &event)
 	    }
 	}
     }
+  else if (event.ptid.is_pid ())
+    {
+      /* This may be the first time we see the inferior report
+	 a stop.  */
+      inferior *inf = find_inferior_ptid (event.target, event.ptid);
+      if (inf->needs_setup)
+	setup_inferior (0);
+
+      /* This is needed to mark all the relevant threads in
+	 case the event is received from an all-stop
+	 target.  */
+      mark_non_executing_threads (event.target, event.ptid, event.ws);
+
+      /* Save the waitstatus for later.  */
+      *inf->control.waitstatus = event.ws;
+    }
   else
     {
       thread_info *t = event.target->find_thread (event.ptid);

-- 
2.34.1

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