Add single stepping logic for linux arm

Linux arm don't support hardware stepping (neither mismatch
breakpoints). This patch implement signle stepping with doing a software
emulation of the next instruction and then setting a temporary
breakpoint at the address where the thread will stop next.

Differential revision: http://reviews.llvm.org/D8976

llvm-svn: 234987
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
index be205f8..f44980d 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
@@ -192,6 +192,10 @@
         std::unique_ptr<ThreadStateCoordinator> m_coordinator_up;
         HostThread m_coordinator_thread;
 
+        // List of thread ids stepping with a breakpoint with the address of
+        // the relevan breakpoint
+        std::map<lldb::tid_t, lldb::addr_t> m_threads_stepping_with_breakpoint;
+
         struct OperationArgs
         {
             OperationArgs(NativeProcessLinux *monitor);