Add a new -a / --address argument to image show-unwind to get the
unwind instructions for a function/symbol which contains that
address.

Update the unwind_diagnose.py script to use this instead of doing
image show-unwind by name to avoid cases where there are multiple
name definitions.

llvm-svn: 180079
diff --git a/lldb/examples/python/unwind_diagnose.py b/lldb/examples/python/unwind_diagnose.py
index ee2069b..8b60f4d 100644
--- a/lldb/examples/python/unwind_diagnose.py
+++ b/lldb/examples/python/unwind_diagnose.py
@@ -182,7 +182,10 @@
             print ""
             print "Unwind instructions for %s, frame %d" % (frame.GetFunctionName(), frame.GetFrameID())
             print ""
-            debugger.HandleCommand('image show-unwind -n "%s"' % frame.GetFunctionName())
+            if lldb_major > 300 or (lldb_major == 300 and lldb_minor >= 20):
+              debugger.HandleCommand('image show-unwind -a "0x%x"' % frame.GetPC())
+            else:
+              debugger.HandleCommand('image show-unwind -n "%s"' % frame.GetFunctionName())
 
 def create_unwind_diagnose_options():
   usage = "usage: %prog"