Index: tools/llvm-pdbdump/LLVMOutputStyle.cpp
===================================================================
--- tools/llvm-pdbdump/LLVMOutputStyle.cpp
+++ tools/llvm-pdbdump/LLVMOutputStyle.cpp
@@ -303,14 +303,17 @@
 
   recordKnownUsedPage(PS, File.getBlockMapIndex()); // Stream Table
 
-  for (auto DB : File.getDirectoryBlockArray()) {
+  for (auto DB : File.getDirectoryBlockArray())
     recordKnownUsedPage(PS, DB);
-  }
-  for (auto &SE : File.getStreamMap()) {
-    for (auto &S : SE) {
-      recordKnownUsedPage(PS, S);
-    }
-  }
+
+  // Record pages used by streams. Note that pages for stream 0
+  // are considered being unused because that's what MSVC tools do.
+  // Stream 0 doesn't contain actual data, so it makes some sense,
+  // though it's a bit confusing to us.
+  for (auto &SE : File.getStreamMap())
+    for (auto &S : SE)
+      if (S != 0)
+        recordKnownUsedPage(PS, S);
 
   dumpBitVector("Msf Free Pages", FPM);
   dumpBitVector("Orphaned Pages", PS.OrphanedPages);