Prevent client from querying each thread's PC at each stop.

Summary:
The server was no longer sending the thread PCs the way the client
expected them.
I changed the server to send them back as a threadstop info field,
similar to the Apple version of the server.
I also changed the client to look for them there, before querying the
server.
I added a test to ensure the server doesn't stop sending them.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D28880
Author: Jason Majors

llvm-svn: 292611

1 files changed, 23 insertions, 21 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 992a71912cd..397c57f2576 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -1649,27 +1649,8 @@ bool ProcessGDBRemote::UpdateThreadList(ThreadList &old_thread_list,
                       __FUNCTION__, static_cast<void *>(thread_sp.get()),
                       thread_sp->GetID());
       }
-      // The m_thread_pcs vector has pc values in big-endian order, not
-      // target-endian, unlike most
-      // of the register read/write packets in gdb-remote protocol.
-      // Early in the process startup, we may not yet have set the process
-      // ByteOrder so we ignore these;
-      // they are a performance improvement over fetching thread register values
-      // individually, the
-      // method we will fall back to if needed.
-      if (m_thread_ids.size() == m_thread_pcs.size() && thread_sp.get() &&
-          GetByteOrder() != eByteOrderInvalid) {
-        ThreadGDBRemote *gdb_thread =
-            static_cast<ThreadGDBRemote *>(thread_sp.get());
-        RegisterContextSP reg_ctx_sp(thread_sp->GetRegisterContext());
-        if (reg_ctx_sp) {
-          uint32_t pc_regnum = reg_ctx_sp->ConvertRegisterKindToRegisterNumber(
-              eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
-          if (pc_regnum != LLDB_INVALID_REGNUM) {
-            gdb_thread->PrivateSetRegisterValue(pc_regnum, m_thread_pcs[i]);
-          }
-        }
-      }
+
+      SetThreadPc(thread_sp, i);
       new_thread_list.AddThreadSortedByIndexID(thread_sp);
     }
   }
@@ -1689,6 +1670,22 @@ bool ProcessGDBRemote::UpdateThreadList(ThreadList &old_thread_list,
   return true;
 }
 
+void ProcessGDBRemote::SetThreadPc(const ThreadSP &thread_sp, uint64_t index) {
+  if (m_thread_ids.size() == m_thread_pcs.size() && thread_sp.get() &&
+      GetByteOrder() != eByteOrderInvalid) {
+    ThreadGDBRemote *gdb_thread =
+        static_cast<ThreadGDBRemote *>(thread_sp.get());
+    RegisterContextSP reg_ctx_sp(thread_sp->GetRegisterContext());
+    if (reg_ctx_sp) {
+      uint32_t pc_regnum = reg_ctx_sp->ConvertRegisterKindToRegisterNumber(
+          eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
+      if (pc_regnum != LLDB_INVALID_REGNUM) {
+        gdb_thread->PrivateSetRegisterValue(pc_regnum, m_thread_pcs[index]);
+      }
+    }
+  }
+}
+
 bool ProcessGDBRemote::GetThreadStopInfoFromJSON(
     ThreadGDBRemote *thread, const StructuredData::ObjectSP &thread_infos_sp) {
   // See if we got thread stop infos for all threads via the "jThreadsInfo"
@@ -1774,6 +1771,11 @@ ThreadSP ProcessGDBRemote::SetThreadStopInfo(
           static_cast<ThreadGDBRemote *>(thread_sp.get());
       gdb_thread->GetRegisterContext()->InvalidateIfNeeded(true);
 
+      auto iter = std::find(m_thread_ids.begin(), m_thread_ids.end(), tid);
+      if (iter != m_thread_ids.end()) {
+        SetThreadPc(thread_sp, iter - m_thread_ids.begin());
+      }
+
       for (const auto &pair : expedited_register_map) {
         StringExtractor reg_value_extractor;
         reg_value_extractor.GetStringRef() = pair.second;