Improve LLDB prompt handling

Summary:
There is an issue in lldb where the command prompt can appear at the wrong time. The partial fix
we have in for this is not working all the time and is introducing unnecessary delays. This
change does:
- Change Process:SyncIOHandler to use integer start id's for synchronization to avoid it being
  confused by quick start-stop cycles. I picked this up from a suggested patch by Greg to
  lldb-dev.
- coordinates printing of asynchronous text with the iohandlers. This is also based on a
  (different) Greg's patch, but I have added stronger synchronization to it to avoid races.

Together, these changes solve the prompt problem for me on linux (both with and without libedit).
I think they should behave similarly on Mac and FreeBSD and I think they will not make matters
worse for windows.

Test Plan: Prompt comes out alright. All tests still pass on linux.

Reviewers: clayborg, emaste, zturner

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D9823

llvm-svn: 238313

1 files changed, 6 insertions, 4 deletions

diff --git a/lldb/source/Commands/CommandObjectProcess.cpp b/lldb/source/Commands/CommandObjectProcess.cpp
index 14b7e2f..e9ca802 100644
--- a/lldb/source/Commands/CommandObjectProcess.cpp
+++ b/lldb/source/Commands/CommandObjectProcess.cpp
@@ -270,7 +270,7 @@ protected:
                 // 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_sp->SyncIOHandler(2000);
+                process_sp->SyncIOHandler (0, 2000);
 
                 const char *data = stream.GetData();
                 if (data && strlen(data) > 0)
@@ -762,6 +762,8 @@ protected:
                 }
             }
 
+            const uint32_t iohandler_id = process->GetIOHandlerID();
+
             StreamString stream;
             Error error;
             if (synchronous_execution)
@@ -772,9 +774,9 @@ protected:
             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);
+                 // handler and show an (lldb) prompt before HandlePrivateEvent (from PrivateStateThread) has
+                 // a chance to call PushProcessIOHandler().
+                process->SyncIOHandler(iohandler_id, 2000);
 
                 result.AppendMessageWithFormat ("Process %" PRIu64 " resuming\n", process->GetID());
                 if (synchronous_execution)