Simplify ObjectFile::GetArchitecture

Summary:
instead of returning the architecture through by-ref argument and a
boolean value indicating success, we can just return the ArchSpec
directly. Since the ArchSpec already has an invalid state, it can be
used to denote the failure without the additional bool.

Reviewers: clayborg, zturner, espindola

Subscribers: emaste, arichardson, JDevlieghere, lldb-commits

Differential Revision: https://reviews.llvm.org/D56129

llvm-svn: 350291
diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h
index f93b831..cf815b6 100644
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.h
@@ -110,7 +110,7 @@
 
   void Dump(lldb_private::Stream *s) override;
 
-  bool GetArchitecture(lldb_private::ArchSpec &arch) override;
+  lldb_private::ArchSpec GetArchitecture() override;
 
   bool GetUUID(lldb_private::UUID *uuid) override;