Fix iohandler prompt race condition.

This issue caused the lldb prompt to not show up in certain cases, very
noticeable on Linux systems.

See details on this review:
http://reviews.llvm.org/D4863

And on this lldb-commits thread:
http://lists.cs.uiuc.edu/pipermail/lldb-commits/Week-of-Mon-20140811/012306.html

Change by Shawn Best.

(Much useful help and testing by the rest of the community, thanks all!)

llvm-svn: 215446

1 files changed, 7 insertions, 1 deletions

diff --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index 5dde4dd7d07..5678ae40464 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -773,10 +773,16 @@ protected:
                     process->GetThreadList().GetThreadAtIndex(idx)->SetResumeState (eStateRunning, override_suspend);
                 }
             }
-            
+
             Error error(process->Resume());
+
             if (error.Success())
             {
+                // There is a race condition where this thread will return up the call stack to the main command
+                // handler and show an (lldb) prompt before HandlePrivateEvent (from PrivateStateThread) has
+                // a chance to call PushProcessIOHandler().
+                process->SyncIOHandler(2000);
+
                 result.AppendMessageWithFormat ("Process %" PRIu64 " resuming\n", process->GetID());
                 if (synchronous_execution)
                 {