Revert "[lldb/Core] Fix a race in the Communication class"

This reverts commit ebb0713 -- it seems
to introduce a deadlock in some circumstances.

Author: labath

lldb/source/Core/Communication.cpp

@@ -315,25 +315,28 @@ lldb::thread_result_t Communication::ReadThread(lldb::thread_arg_t p) {
   Status error;
   ConnectionStatus status = eConnectionStatusSuccess;
   bool done = false;
-  bool disconnect = false;
   while (!done && comm->m_read_thread_enabled) {
     size_t bytes_read = comm->ReadFromConnection(
         buf, sizeof(buf), std::chrono::seconds(5), status, &error);
-    if (bytes_read > 0 || status == eConnectionStatusEndOfFile)
+    if (bytes_read > 0)
       comm->AppendBytesToCache(buf, bytes_read, true, status);
+    else if ((bytes_read == 0) && status == eConnectionStatusEndOfFile) {
+      if (comm->GetCloseOnEOF())
+        comm->Disconnect();
+      comm->AppendBytesToCache(buf, bytes_read, true, status);
+    }
 
     switch (status) {
     case eConnectionStatusSuccess:
       break;
 
     case eConnectionStatusEndOfFile:
       done = true;
-      disconnect = comm->GetCloseOnEOF();
       break;
     case eConnectionStatusError: // Check GetError() for details
       if (error.GetType() == eErrorTypePOSIX && error.GetError() == EIO) {
         // EIO on a pipe is usually caused by remote shutdown
-        disconnect = comm->GetCloseOnEOF();
+        comm->Disconnect();
         done = true;
       }
       if (error.Fail())
@@ -362,15 +365,9 @@ lldb::thread_result_t Communication::ReadThread(lldb::thread_arg_t p) {
   if (log)
     LLDB_LOGF(log, "%p Communication::ReadThread () thread exiting...", p);
 
-  comm->BroadcastEvent(eBroadcastBitNoMorePendingInput);
-  {
-    std::lock_guard<std::mutex> guard(comm->m_synchronize_mutex);
-    comm->m_read_thread_did_exit = true;
-    if (disconnect)
-      comm->Disconnect();
-  }
-
+  comm->m_read_thread_did_exit = true;
   // Let clients know that this thread is exiting
+  comm->BroadcastEvent(eBroadcastBitNoMorePendingInput);
   comm->BroadcastEvent(eBroadcastBitReadThreadDidExit);
   return {};
 }

lldb/unittests/Core/CMakeLists.txt

@@ -1,5 +1,4 @@
 add_lldb_unittest(LLDBCoreTests
-  CommunicationTest.cpp
   MangledTest.cpp
   RichManglingContextTest.cpp
   StreamCallbackTest.cpp