Add a way for an ObjectFile to indicate that assembly emulation
should not be used for this module -- for use when an ObjectFile
knows that it does not have meaningful or accurate function start
addresses.  

More commonly, it is not clear that function start addresses are
missing in a module.  There are certain cases on Mac OS X where we
can tell that a Mach-O binary has been stripped of this essential
information, and the unwinder can end up emulating many megabytes
of instructions for a single "function" in the binary.

When a Mach-O binary is missing both an LC_FUNCTION_STARTS load 
command (very unusual) and an eh_frame section, then we will assume 
it has also been stripped of symbols and that instruction emulation
will not be useful on this module.

<rdar://problem/25988067> 

llvm-svn: 268475
diff --git a/lldb/source/Symbol/UnwindTable.cpp b/lldb/source/Symbol/UnwindTable.cpp
index ac7a9b0..d114109 100644
--- a/lldb/source/Symbol/UnwindTable.cpp
+++ b/lldb/source/Symbol/UnwindTable.cpp
@@ -189,3 +189,9 @@
 {
     return m_object_file.GetArchitecture (arch);
 }
+
+bool
+UnwindTable::GetAllowAssemblyEmulationUnwindPlans ()
+{
+    return m_object_file.AllowAssemblyEmulationUnwindPlans ();
+}