[llvm-pdbutil] Support PDBs without a DBI stream

Differential Revision: https://reviews.llvm.org/D50258

llvm-svn: 339045
diff --git a/llvm/lib/DebugInfo/PDB/Native/PDBFile.cpp b/llvm/lib/DebugInfo/PDB/Native/PDBFile.cpp
index 78b1193..c5ce3e0 100644
--- a/llvm/lib/DebugInfo/PDB/Native/PDBFile.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/PDBFile.cpp
@@ -401,7 +401,9 @@
   return 4;
 }
 
-bool PDBFile::hasPDBDbiStream() const { return StreamDBI < getNumStreams(); }
+bool PDBFile::hasPDBDbiStream() const {
+  return StreamDBI < getNumStreams() && getStreamByteSize(StreamDBI) > 0;
+}
 
 bool PDBFile::hasPDBGlobalsStream() {
   auto DbiS = getPDBDbiStream();