Dwarf parser: don't lookup void typedefs in the DWO

Summary:
void typedefs do not have a DW_AT_type attribute, so we end up with an empty encoding_uid
variable. These don't need to be looked up and trying to look that will assert in a debug build.

Reviewers: clayborg

Subscribers: lldb-commits, tberghammer

Differential Revision: http://reviews.llvm.org/D22218

llvm-svn: 275164

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -328,7 +328,7 @@ DWARFASTParserClang::ParseTypeFromDWARF (const SymbolContext& sc,
                         }
                     }
 
-                    if (tag == DW_TAG_typedef)
+                    if (tag == DW_TAG_typedef && encoding_uid.IsValid())
                     {
                         // Try to parse a typedef from the DWO file first as modules
                         // can contain typedef'ed structures that have no names like: