Handle O reply packets during qRcmd

Summary:
Gdb servers like openocd may send many $O reply packets for the client to output during a qRcmd command sequence.  Currently, lldb interprets the first O packet as an unexpected response.  Besides generating no output, this causes lldb to get out of sync with future commands because it continues reading O packets from the first command as response to subsequent commands.

This patch handles any O packets during an qRcmd, treating the first non-O packet as the true response.

Preliminary discussion at http://lists.llvm.org/pipermail/lldb-dev/2018-January/013078.html

Reviewers: clayborg

Reviewed By: clayborg

Subscribers: labath, lldb-commits

Differential Revision: https://reviews.llvm.org/D41745
Patch by Owen Shaw <llvm@owenpshaw.net>

llvm-svn: 322190

1 files changed, 4 insertions, 3 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 44efcbe20ae..78399b733a7 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -5145,10 +5145,11 @@ public:
 
       bool send_async = true;
       StringExtractorGDBRemote response;
-      process->GetGDBRemote().SendPacketAndWaitForResponse(
-          packet.GetString(), response, send_async);
-      result.SetStatus(eReturnStatusSuccessFinishResult);
       Stream &output_strm = result.GetOutputStream();
+      process->GetGDBRemote().SendPacketAndReceiveResponseWithOutputSupport(
+          packet.GetString(), response, send_async,
+          [&output_strm](llvm::StringRef output) { output_strm << output; });
+      result.SetStatus(eReturnStatusSuccessFinishResult);
       output_strm.Printf("  packet: %s\n", packet.GetData());
       const std::string &response_str = response.GetStringRef();