Index: include/llvm/DebugInfo/PDB/Raw/ModStream.h
===================================================================
--- /dev/null
+++ include/llvm/DebugInfo/PDB/Raw/ModStream.h
@@ -0,0 +1,43 @@
+//===- ModStream.h - PDB Module Info Stream Access ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_PDB_RAW_PDBMODSTREAM_H
+#define LLVM_DEBUGINFO_PDB_RAW_PDBMODSTREAM_H
+
+#include "llvm/DebugInfo/PDB/Raw/ByteStream.h"
+#include "llvm/DebugInfo/PDB/Raw/MappedBlockStream.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+namespace pdb {
+class PDBFile;
+class ModInfo;
+
+class ModStream {
+public:
+  ModStream(PDBFile &File, const ModInfo &Module);
+  ~ModStream();
+
+  Error reload();
+
+private:
+  PDBFile &Pdb;
+  const ModInfo &Mod;
+
+  MappedBlockStream Stream;
+
+  ByteStream SymbolsSubstream;
+  ByteStream LinesSubstream;
+  ByteStream C13LinesSubstream;
+  ByteStream GlobalRefsSubstream;
+};
+}
+}
+
+#endif
Index: lib/DebugInfo/PDB/CMakeLists.txt
===================================================================
--- lib/DebugInfo/PDB/CMakeLists.txt
+++ lib/DebugInfo/PDB/CMakeLists.txt
@@ -31,6 +31,7 @@
   Raw/ByteStream.cpp
   Raw/MappedBlockStream.cpp
   Raw/ModInfo.cpp
+  Raw/ModStream.cpp
   Raw/PDBFile.cpp
   Raw/DbiStream.cpp
   Raw/InfoStream.cpp
Index: lib/DebugInfo/PDB/Raw/ByteStream.cpp
===================================================================
--- lib/DebugInfo/PDB/Raw/ByteStream.cpp
+++ lib/DebugInfo/PDB/Raw/ByteStream.cpp
@@ -24,7 +24,7 @@
 ByteStream::~ByteStream() { reset(); }
 
 void ByteStream::reset() {
-  if (Owned)
+  if (Owned && Data.size() > 0)
     delete[] Data.data();
   Owned = false;
   Data = MutableArrayRef<uint8_t>();
@@ -38,7 +38,8 @@
 
 void ByteStream::initialize(uint32_t Length) {
   reset();
-  Data = MutableArrayRef<uint8_t>(new uint8_t[Length], Length);
+  if (Length > 0)
+    Data = MutableArrayRef<uint8_t>(new uint8_t[Length], Length);
   Owned = true;
 }
 
Index: lib/DebugInfo/PDB/Raw/ModStream.cpp
===================================================================
--- /dev/null
+++ lib/DebugInfo/PDB/Raw/ModStream.cpp
@@ -0,0 +1,51 @@
+//===- ModStream.cpp - PDB Module Info Stream Access ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/PDB/Raw/ModStream.h"
+#include "llvm/DebugInfo/PDB/Raw/ModInfo.h"
+#include "llvm/DebugInfo/PDB/Raw/RawError.h"
+#include "llvm/DebugInfo/PDB/Raw/StreamReader.h"
+
+using namespace llvm;
+using namespace llvm::pdb;
+
+ModStream::ModStream(PDBFile &File, const ModInfo &Module)
+    : Pdb(File), Mod(Module), Stream(Module.getModuleStreamIndex(), File) {}
+
+ModStream::~ModStream() {}
+
+Error ModStream::reload() {
+  StreamReader Reader(Stream);
+
+  uint32_t SymbolSize = Mod.getSymbolDebugInfoByteSize();
+  uint32_t C11Size = Mod.getLineInfoByteSize();
+  uint32_t C13Size = Mod.getC13LineInfoByteSize();
+
+  if (C11Size > 0 && C13Size > 0)
+    return llvm::make_error<RawError>(raw_error_code::corrupt_file,
+                                      "Module has both C11 and C13 line info");
+
+  if (auto EC = SymbolsSubstream.initialize(Reader, SymbolSize))
+    return EC;
+  if (auto EC = LinesSubstream.initialize(Reader, C11Size))
+    return EC;
+  if (auto EC = C13LinesSubstream.initialize(Reader, C13Size))
+    return EC;
+
+  uint32_t GlobalRefsSize;
+  if (auto EC = Reader.readInteger(GlobalRefsSize))
+    return EC;
+  if (auto EC = GlobalRefsSubstream.initialize(Reader, GlobalRefsSize))
+    return EC;
+  if (Reader.bytesRemaining() > 0)
+    return llvm::make_error<RawError>(raw_error_code::corrupt_file,
+                                      "Unexpected bytes in module stream.");
+
+  return Error::success();
+}
Index: tools/llvm-pdbdump/llvm-pdbdump.cpp
===================================================================
--- tools/llvm-pdbdump/llvm-pdbdump.cpp
+++ tools/llvm-pdbdump/llvm-pdbdump.cpp
@@ -41,6 +41,7 @@
 #include "llvm/DebugInfo/PDB/Raw/InfoStream.h"
 #include "llvm/DebugInfo/PDB/Raw/MappedBlockStream.h"
 #include "llvm/DebugInfo/PDB/Raw/ModInfo.h"
+#include "llvm/DebugInfo/PDB/Raw/ModStream.h"
 #include "llvm/DebugInfo/PDB/Raw/NameHashTable.h"
 #include "llvm/DebugInfo/PDB/Raw/PDBFile.h"
 #include "llvm/DebugInfo/PDB/Raw/RawSession.h"