<rdar://problem/12586010>

Python OS plug-ins now fetch thread registers lazily.

Also changed SBCommandInterpreter::HandleCommand() to not take the API lock. The logic here is that from the command line you can execute a command that might result in another thread (like the private process thread) to execute python or run any code that can re-enter the public API. When this happens, a deadlock immediately occurs for things like "process launch" and "process attach".

llvm-svn: 171901

lldb/source/Plugins/Process/Utility/ThreadMemory.cpp

@@ -135,7 +135,10 @@ ThreadMemory::GetPrivateStopReason ()
 void
 ThreadMemory::RefreshStateAfterStop()
 {
-    RegisterContextSP reg_ctx_sp(GetRegisterContext());
+    // Don't fetch the registers by calling Thread::GetRegisterContext() below.
+    // We might not have fetched any registers yet and we don't want to fetch
+    // the registers just to call invalidate on them...
+    RegisterContextSP reg_ctx_sp(m_reg_context_sp);
     if (reg_ctx_sp)
     {
         const bool force = true;