Changes to lldb and debugserver to reduce extraneous memory reads

at each public stop to improve performance a bit.  Most of the 
information lldb needed was already in the jThreadsInfo response;
complete that information and catch a few cases where we could still
fall back to getting the information via discrete memory reads.


debugserver adds 'associated_with_dispatch_queue' and 'dispatch_queue_t
keys to the jThreadsInfo response for all the threads.  lldb needs the
dispatch_queue_t value.  And associated_with_dispatch_queue helps to
identify which threads definitively don't have any queue information so
lldb doesn't try to do memory reads to get that information just because
it was absent in the jThreadsInfo response.

Remove the queue information from the questionmark (T) packet.  We'll
get the information for all threads via the jThreadsInfo response -
sending the information for the stopping thread (on all the private
stops, plus the less frequent public stop) was unnecessary information
being sent over the wire.

SystemRuntimeMacOSX will try to get information about queues by asking
the Threads for them, instead of reading memory.  

ProcessGDBRemote changes to recognize the new keys being sent in the
jThreadsInfo response.  Changes to ThreadGDBRemote to track the new
information.  Also, when a thread is marked as definitively not 
associated with a libdispatch queue, don't fall back to the system
runtime to try memory reads to find the queue name / kind / ID etc.


<rdar://problem/23309359> 

llvm-svn: 257453

1 files changed, 40 insertions, 1 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 83a0d5bd94f..2bf882364cc 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -2034,6 +2034,8 @@ ProcessGDBRemote::SetThreadStopInfo (lldb::tid_t tid,
                                      const std::vector<addr_t> &exc_data,
                                      addr_t thread_dispatch_qaddr,
                                      bool queue_vars_valid, // Set to true if queue_name, queue_kind and queue_serial are valid
+                                     LazyBool associated_with_dispatch_queue,
+                                     addr_t dispatch_queue_t,
                                      std::string &queue_name,
                                      QueueKind queue_kind,
                                      uint64_t queue_serial)
@@ -2074,10 +2076,15 @@ ProcessGDBRemote::SetThreadStopInfo (lldb::tid_t tid,
             gdb_thread->SetThreadDispatchQAddr (thread_dispatch_qaddr);
             // Check if the GDB server was able to provide the queue name, kind and serial number
             if (queue_vars_valid)
-                gdb_thread->SetQueueInfo(std::move(queue_name), queue_kind, queue_serial);
+                gdb_thread->SetQueueInfo(std::move(queue_name), queue_kind, queue_serial, dispatch_queue_t, associated_with_dispatch_queue);
             else
                 gdb_thread->ClearQueueInfo();
 
+            gdb_thread->SetAssociatedWithLibdispatchQueue (associated_with_dispatch_queue);
+
+            if (dispatch_queue_t != LLDB_INVALID_ADDRESS)
+                gdb_thread->SetQueueLibdispatchQueueAddress (dispatch_queue_t);
+
             // Make sure we update our thread stop reason just once
             if (!thread_sp->StopInfoIsUpToDate())
             {
@@ -2248,6 +2255,8 @@ ProcessGDBRemote::SetThreadStopInfo (StructuredData::Dictionary *thread_dict)
     static ConstString g_key_metype("metype");
     static ConstString g_key_medata("medata");
     static ConstString g_key_qaddr("qaddr");
+    static ConstString g_key_dispatch_queue_t("dispatch_queue_t");
+    static ConstString g_key_associated_with_dispatch_queue("associated_with_dispatch_queue");
     static ConstString g_key_queue_name("qname");
     static ConstString g_key_queue_kind("qkind");
     static ConstString g_key_queue_serial_number("qserialnum");
@@ -2270,6 +2279,8 @@ ProcessGDBRemote::SetThreadStopInfo (StructuredData::Dictionary *thread_dict)
     addr_t thread_dispatch_qaddr = LLDB_INVALID_ADDRESS;
     ExpeditedRegisterMap expedited_register_map;
     bool queue_vars_valid = false;
+    addr_t dispatch_queue_t = LLDB_INVALID_ADDRESS;
+    LazyBool associated_with_dispatch_queue = eLazyBoolCalculate;
     std::string queue_name;
     QueueKind queue_kind = eQueueKindUnknown;
     uint64_t queue_serial_number = 0;
@@ -2286,6 +2297,8 @@ ProcessGDBRemote::SetThreadStopInfo (StructuredData::Dictionary *thread_dict)
                           &exc_data,
                           &thread_dispatch_qaddr,
                           &queue_vars_valid,
+                          &associated_with_dispatch_queue,
+                          &dispatch_queue_t,
                           &queue_name,
                           &queue_kind,
                           &queue_serial_number]
@@ -2346,6 +2359,21 @@ ProcessGDBRemote::SetThreadStopInfo (StructuredData::Dictionary *thread_dict)
             if (queue_serial_number != 0)
                 queue_vars_valid = true;
         }
+        else if (key == g_key_dispatch_queue_t)
+        {
+            dispatch_queue_t = object->GetIntegerValue(0);
+            if (dispatch_queue_t != 0 && dispatch_queue_t != LLDB_INVALID_ADDRESS)
+                queue_vars_valid = true;
+        }
+        else if (key == g_key_associated_with_dispatch_queue)
+        {
+            queue_vars_valid = true;
+            bool associated = object->GetBooleanValue ();
+            if (associated)
+                associated_with_dispatch_queue = eLazyBoolYes;
+            else
+                associated_with_dispatch_queue = eLazyBoolNo;
+        }
         else if (key == g_key_reason)
         {
             reason = object->GetStringValue();
@@ -2416,6 +2444,8 @@ ProcessGDBRemote::SetThreadStopInfo (StructuredData::Dictionary *thread_dict)
                               exc_data,
                               thread_dispatch_qaddr,
                               queue_vars_valid,
+                              associated_with_dispatch_queue,
+                              dispatch_queue_t,
                               queue_name,
                               queue_kind,
                               queue_serial_number);
@@ -2461,6 +2491,8 @@ ProcessGDBRemote::SetThreadStopInfo (StringExtractor& stop_packet)
             std::vector<addr_t> exc_data;
             addr_t thread_dispatch_qaddr = LLDB_INVALID_ADDRESS;
             bool queue_vars_valid = false; // says if locals below that start with "queue_" are valid
+            addr_t dispatch_queue_t = LLDB_INVALID_ADDRESS;
+            LazyBool associated_with_dispatch_queue = eLazyBoolCalculate;
             std::string queue_name;
             QueueKind queue_kind = eQueueKindUnknown;
             uint64_t queue_serial_number = 0;
@@ -2554,6 +2586,11 @@ ProcessGDBRemote::SetThreadStopInfo (StringExtractor& stop_packet)
                 {
                     thread_dispatch_qaddr = StringConvert::ToUInt64 (value.c_str(), 0, 16);
                 }
+                else if (key.compare("dispatch_queue_t") == 0)
+                {
+                    queue_vars_valid = true;
+                    dispatch_queue_t = StringConvert::ToUInt64 (value.c_str(), 0, 16);
+                }
                 else if (key.compare("qname") == 0)
                 {
                     queue_vars_valid = true;
@@ -2678,6 +2715,8 @@ ProcessGDBRemote::SetThreadStopInfo (StringExtractor& stop_packet)
                                                     exc_data,
                                                     thread_dispatch_qaddr,
                                                     queue_vars_valid,
+                                                    associated_with_dispatch_queue,
+                                                    dispatch_queue_t,
                                                     queue_name,
                                                     queue_kind,
                                                     queue_serial_number);