Remote Non-Stop Support

 
Summary:
 
This patch is the beginnings of support for Non-stop mode in the remote protocol. Letting a user examine stopped threads, while other threads execute freely.

Non-stop mode is enabled using the setting target.non-stop-mode, which sends a QNonStop packet when establishing the remote connection.
Changes are also made to treat the '?' stop reply packet differently in non-stop mode, according to spec https://sourceware.org/gdb/current/onlinedocs/gdb/Remote-Non_002dStop.html#Remote-Non_002dStop.
A setting for querying the remote for default thread on setup is also included.

Handling of '%' async notification packets will be added next.

Reviewers: clayborg

Subscribers: lldb-commits, ADodds, ted, deepak2427

Differential Revision: http://reviews.llvm.org/D9656

llvm-svn: 237239

1 files changed, 35 insertions, 0 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index 07c51dc5c02..ca74e55b439 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1621,6 +1621,22 @@ GDBRemoteCommunicationClient::GetGDBServerProgramVersion()
 }
 
 bool
+GDBRemoteCommunicationClient::GetDefaultThreadId (lldb::tid_t &tid)
+{
+    StringExtractorGDBRemote response;
+    if (SendPacketAndWaitForResponse("qC",response,false) !=  PacketResult::Success)
+        return false;
+
+    if (!response.IsNormalResponse())
+        return false;
+
+    if (response.GetChar() == 'Q' && response.GetChar() == 'C')
+        tid = response.GetHexMaxU32(true, -1);
+
+    return true;
+}
+
+bool
 GDBRemoteCommunicationClient::GetHostInfo (bool force)
 {
     Log *log (ProcessGDBRemoteLog::GetLogIfAnyCategoryIsSet (GDBR_LOG_PROCESS));
@@ -2759,6 +2775,25 @@ GDBRemoteCommunicationClient::GetGroupName (uint32_t gid, std::string &name)
     return false;
 }
 
+bool
+GDBRemoteCommunicationClient::SetNonStopMode (const bool enable)
+{
+    // Form non-stop packet request
+    char packet[32];
+    const int packet_len = ::snprintf(packet, sizeof(packet), "QNonStop:%1d", (int)enable);
+    assert(packet_len < (int)sizeof(packet));
+
+    StringExtractorGDBRemote response;
+    // Send to target
+    if (SendPacketAndWaitForResponse(packet, packet_len, response, false) == PacketResult::Success)
+        if (response.IsOKResponse())
+            return true;
+
+    // Failed or not supported
+    return false;
+
+}
+
 void
 GDBRemoteCommunicationClient::TestPacketSpeed (const uint32_t num_packets)
 {