[llvm-pdbutil] Support PDBs without a DBI stream

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

llvm-svn: 339045
diff --git a/llvm/tools/llvm-pdbutil/InputFile.cpp b/llvm/tools/llvm-pdbutil/InputFile.cpp
index 7b5af7e..b201964 100644
--- a/llvm/tools/llvm-pdbutil/InputFile.cpp
+++ b/llvm/tools/llvm-pdbutil/InputFile.cpp
@@ -41,6 +41,10 @@
 
   auto &Dbi = Err(File.getPDBDbiStream());
   const auto &Modules = Dbi.modules();
+  if (Index >= Modules.getModuleCount())
+    return make_error<RawError>(raw_error_code::index_out_of_bounds,
+                                "Invalid module index");
+
   auto Modi = Modules.getModuleDescriptor(Index);
 
   ModuleName = Modi.getModuleName();