Get initial thread state coordinator integration working.

* Fixed bug in run loop where run loop return enum was being treated
  erroneously like an int, causing the TSC event loop to terminate
  prematurely.

* Added an explicit scope in NativeProcessLinux::Resume() for the
  threads lock lifetime.  (This was likely unnecessary but is
  more explicit.)

* Fixed a bug in ThreadStateCoordinator where resume execution was
  not updating the internal state about the thread assumed to be
  running now.  I'll add a test and upstream this in a moment.

* Added a verbose logging mechanism to event processing within
  ThreadStateCoordinator.  It is currently enabled when the
  'log enable lldb thread' is true upon inferior launch/attach.

llvm-svn: 227909

lldb/source/Plugins/Process/Linux/NativeProcessLinux.h

@@ -31,6 +31,7 @@ namespace lldb_private
 {
     class Error;
     class Module;
+    class ThreadStateCoordinator;
     class Scalar;
 
     /// @class NativeProcessLinux
@@ -183,21 +184,12 @@ namespace lldb_private
         sem_t m_operation_pending;
         sem_t m_operation_done;
 
-        // Set of tids we're waiting to stop before we notify the delegate of
-        // the stopped state.  We only notify the delegate after all threads
-        // ordered to stop have signaled their stop.
-        std::unordered_set<lldb::tid_t> m_wait_for_stop_tids;
-        lldb_private::Mutex m_wait_for_stop_tids_mutex;
-
-        std::unordered_set<lldb::tid_t> m_wait_for_group_stop_tids;
-        lldb::tid_t m_group_stop_signal_tid;
-        int m_group_stop_signal;
-        lldb_private::Mutex m_wait_for_group_stop_tids_mutex;
-
         lldb_private::LazyBool m_supports_mem_region;
         std::vector<MemoryRegionInfo> m_mem_region_cache;
         lldb_private::Mutex m_mem_region_cache_mutex;
 
+        std::unique_ptr<ThreadStateCoordinator> m_coordinator_up;
+        HostThread m_coordinator_thread;
 
         struct OperationArgs
         {
@@ -334,6 +326,15 @@ namespace lldb_private
         void
         StopOpThread();
 
+        Error
+        StartCoordinatorThread ();
+
+        static void*
+        CoordinatorThread (void *arg);
+
+        void
+        StopCoordinatorThread ();
+
         /// Stops monitoring the child process thread.
         void
         StopMonitor();
@@ -380,16 +381,22 @@ namespace lldb_private
         bool
         SingleStep(lldb::tid_t tid, uint32_t signo);
 
-        /// Safely mark all existing threads as waiting for group stop.
-        /// When the final group stop comes in from the set of group stop threads,
-        /// we'll mark the current thread as signaled_thread_tid and set its stop
-        /// reason as the given signo.  All other threads from group stop notification
-        /// will have thread stop reason marked as signaled with no signo.
+        // ThreadStateCoordinator helper methods.
         void
-        SetGroupStopTids (lldb::tid_t signaled_thread_tid, int signo);
+        NotifyThreadCreateStopped (lldb::tid_t tid);
 
         void
-        OnGroupStop (lldb::tid_t tid);
+        NotifyThreadCreateRunning (lldb::tid_t tid);
+
+        void
+        NotifyThreadDeath (lldb::tid_t tid);
+
+        void
+        NotifyThreadStop (lldb::tid_t tid);
+
+        void
+        CallAfterRunningThreadsStop (lldb::tid_t tid,
+                                     const std::function<void (lldb::tid_t tid)> &call_after_function);
 
         lldb_private::Error
         Detach(lldb::tid_t tid);

lldb/source/Plugins/Process/Linux/ThreadStateCoordinator.cpp

@@ -35,6 +35,9 @@ public:
     {
     }
 
+    virtual std::string
+    GetDescription () = 0;
+
     // Return false if the coordinator should terminate running.
     virtual EventLoopResult
     ProcessEvent (ThreadStateCoordinator &coordinator) = 0;
@@ -55,6 +58,12 @@ public:
     {
         return eventLoopResultStop;
     }
+
+    std::string
+    GetDescription () override
+    {
+        return "EventStopCoordinator";
+    }
 };
 
 //===----------------------------------------------------------------------===//
@@ -190,6 +199,14 @@ public:
             m_request_thread_stop_function (tid);
     }
 
+    std::string
+    GetDescription () override
+    {
+        std::ostringstream description;
+        description << "EventCallAfterThreadsStop (triggering_tid=" << m_triggering_tid << ", request_stop_on_all_unstopped_threads=" << m_request_stop_on_all_unstopped_threads << ")";
+        return description.str ();
+    }
+
 private:
 
     void
@@ -291,6 +308,12 @@ public:
         coordinator.ResetNow ();
         return eventLoopResultContinue;
     }
+
+    std::string
+    GetDescription () override
+    {
+        return "EventReset";
+    }
 };
 
 //===----------------------------------------------------------------------===//
@@ -313,6 +336,14 @@ public:
         return eventLoopResultContinue;
     }
 
+    std::string
+    GetDescription () override
+    {
+        std::ostringstream description;
+        description << "EventThreadStopped (tid=" << m_tid << ")";
+        return description.str ();
+    }
+
 private:
 
     const lldb::tid_t m_tid;
@@ -341,6 +372,14 @@ public:
         return eventLoopResultContinue;
     }
 
+    std::string
+    GetDescription () override
+    {
+        std::ostringstream description;
+        description << "EventThreadCreate (tid=" << m_tid << ", " << (m_is_stopped ? "stopped" : "running") << ")";
+        return description.str ();
+    }
+
 private:
 
     const lldb::tid_t m_tid;
@@ -368,6 +407,14 @@ public:
         return eventLoopResultContinue;
     }
 
+    std::string
+    GetDescription () override
+    {
+        std::ostringstream description;
+        description << "EventThreadDeath (tid=" << m_tid << ")";
+        return description.str ();
+    }
+
 private:
 
     const lldb::tid_t m_tid;
@@ -450,6 +497,14 @@ public:
         return eventLoopResultContinue;
     }
 
+    std::string
+    GetDescription () override
+    {
+        std::ostringstream description;
+        description << "EventRequestResume (tid=" << m_tid << ")";
+        return description.str ();
+    }
+
 private:
 
     const lldb::tid_t m_tid;
@@ -464,7 +519,8 @@ ThreadStateCoordinator::ThreadStateCoordinator (const LogFunction &log_function)
     m_event_queue (),
     m_queue_condition (),
     m_queue_mutex (),
-    m_tid_stop_map ()
+    m_tid_stop_map (),
+    m_log_event_processing (false)
 {
 }
 
@@ -711,7 +767,39 @@ ThreadStateCoordinator::StopCoordinator ()
 ThreadStateCoordinator::EventLoopResult
 ThreadStateCoordinator::ProcessNextEvent ()
 {
-    return DequeueEventWithWait()->ProcessEvent (*this);
+    // Dequeue the next event, synchronous.
+    if (m_log_event_processing)
+        Log ("ThreadStateCoordinator::%s about to dequeue next event in blocking mode", __FUNCTION__);
+
+    EventBaseSP event_sp = DequeueEventWithWait();
+    assert (event_sp && "event should never be null");
+    if (!event_sp)
+    {
+        Log ("ThreadStateCoordinator::%s error: event_sp was null, signaling exit of event loop.", __FUNCTION__);
+        return eventLoopResultStop;
+    }
+
+    if (m_log_event_processing)
+    {
+        Log ("ThreadStateCoordinator::%s about to process event: %s", __FUNCTION__, event_sp->GetDescription ().c_str ());
+    }
+
+    // Process the event.
+    const EventLoopResult result = event_sp->ProcessEvent (*this);
+
+    if (m_log_event_processing)
+    {
+        Log ("ThreadStateCoordinator::%s event processing returned value %s", __FUNCTION__,
+             result == eventLoopResultContinue ? "eventLoopResultContinue" : "eventLoopResultStop");
+    }
+
+    return result;
+}
+
+void
+ThreadStateCoordinator::LogEnableEventProcessing (bool enabled)
+{
+    m_log_event_processing = enabled;
 }
 
 ThreadStateCoordinator::EventCallAfterThreadsStop *

lldb/source/Plugins/Process/Linux/ThreadStateCoordinator.h

@@ -115,6 +115,10 @@ namespace lldb_private
         EventLoopResult
         ProcessNextEvent ();
 
+        // Enable/disable verbose logging of event processing.
+        void
+        LogEnableEventProcessing (bool enabled);
+
     private:
 
         // Typedefs.
@@ -179,6 +183,8 @@ namespace lldb_private
 
         // Maps known TIDs to stop (true) or not-stopped (false) state.
         TIDBoolMap m_tid_stop_map;
+
+        bool m_log_event_processing;
     };
 }