Index: llvm/include/llvm/DebugInfo/PDB/Native/NativeSession.h
===================================================================
--- llvm/include/llvm/DebugInfo/PDB/Native/NativeSession.h
+++ llvm/include/llvm/DebugInfo/PDB/Native/NativeSession.h
@@ -7,11 +7,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_PDB_RAW_RAWSESSION_H
-#define LLVM_DEBUGINFO_PDB_RAW_RAWSESSION_H
+#ifndef LLVM_DEBUGINFO_PDB_NATIVE_NATIVESESSION_H
+#define LLVM_DEBUGINFO_PDB_NATIVE_NATIVESESSION_H
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/PDB/IPDBSession.h"
+#include "llvm/DebugInfo/PDB/Native/DbiModuleDescriptor.h"
+#include "llvm/DebugInfo/PDB/Native/NativeRawSymbol.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Error.h"
 
@@ -30,6 +32,9 @@
   static Error createFromExe(StringRef Path,
                              std::unique_ptr<IPDBSession> &Session);
 
+  std::unique_ptr<PDBSymbolCompiland>
+  createCompilandSymbol(DbiModuleDescriptor MI);
+
   uint64_t getLoadAddress() const override;
   void setLoadAddress(uint64_t Address) override;
   std::unique_ptr<PDBSymbolExe> getGlobalScope() override;
@@ -71,6 +76,7 @@
 private:
   std::unique_ptr<PDBFile> Pdb;
   std::unique_ptr<BumpPtrAllocator> Allocator;
+  std::vector<std::unique_ptr<NativeRawSymbol>> SymbolCache;
 };
 }
 }
Index: llvm/lib/DebugInfo/PDB/Native/NativeEnumModules.cpp
===================================================================
--- llvm/lib/DebugInfo/PDB/Native/NativeEnumModules.cpp
+++ llvm/lib/DebugInfo/PDB/Native/NativeEnumModules.cpp
@@ -32,9 +32,7 @@
 NativeEnumModules::getChildAtIndex(uint32_t Index) const {
   if (Index >= Modules.getModuleCount())
     return nullptr;
-  return std::unique_ptr<PDBSymbol>(new PDBSymbolCompiland(
-      Session, std::unique_ptr<IPDBRawSymbol>(new NativeCompilandSymbol(
-                   Session, 0, Modules.getModuleDescriptor(Index)))));
+  return Session.createCompilandSymbol(Modules.getModuleDescriptor(Index));
 }
 
 std::unique_ptr<PDBSymbol> NativeEnumModules::getNext() {
Index: llvm/lib/DebugInfo/PDB/Native/NativeSession.cpp
===================================================================
--- llvm/lib/DebugInfo/PDB/Native/NativeSession.cpp
+++ llvm/lib/DebugInfo/PDB/Native/NativeSession.cpp
@@ -13,6 +13,7 @@
 #include "llvm/DebugInfo/PDB/GenericError.h"
 #include "llvm/DebugInfo/PDB/IPDBEnumChildren.h"
 #include "llvm/DebugInfo/PDB/IPDBSourceFile.h"
+#include "llvm/DebugInfo/PDB/Native/NativeCompilandSymbol.h"
 #include "llvm/DebugInfo/PDB/Native/NativeExeSymbol.h"
 #include "llvm/DebugInfo/PDB/Native/PDBFile.h"
 #include "llvm/DebugInfo/PDB/Native/RawError.h"
@@ -23,8 +24,10 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/MemoryBuffer.h"
+
 #include <algorithm>
 #include <memory>
+#include <utility>
 
 using namespace llvm;
 using namespace llvm::msf;
@@ -66,12 +69,23 @@
   return make_error<RawError>(raw_error_code::feature_unsupported);
 }
 
+std::unique_ptr<PDBSymbolCompiland>
+NativeSession::createCompilandSymbol(DbiModuleDescriptor MI) {
+  const auto Id = static_cast<uint32_t>(SymbolCache.size());
+  SymbolCache.push_back(
+      llvm::make_unique<NativeCompilandSymbol>(*this, Id, MI));
+  return llvm::make_unique<PDBSymbolCompiland>(
+      *this, std::unique_ptr<IPDBRawSymbol>(SymbolCache[Id]->clone()));
+}
+
 uint64_t NativeSession::getLoadAddress() const { return 0; }
 
 void NativeSession::setLoadAddress(uint64_t Address) {}
 
 std::unique_ptr<PDBSymbolExe> NativeSession::getGlobalScope() {
-  auto RawSymbol = llvm::make_unique<NativeExeSymbol>(*this, 0);
+  const auto Id = static_cast<uint32_t>(SymbolCache.size());
+  SymbolCache.push_back(llvm::make_unique<NativeExeSymbol>(*this, Id));
+  auto RawSymbol = SymbolCache[Id]->clone();
   auto PdbSymbol(PDBSymbol::create(*this, std::move(RawSymbol)));
   std::unique_ptr<PDBSymbolExe> ExeSymbol(
       static_cast<PDBSymbolExe *>(PdbSymbol.release()));
@@ -80,7 +94,10 @@
 
 std::unique_ptr<PDBSymbol>
 NativeSession::getSymbolById(uint32_t SymbolId) const {
-  return nullptr;
+  // If the caller has a SymbolId, it'd better be in our SymbolCache.
+  return SymbolId < SymbolCache.size()
+             ? PDBSymbol::create(*this, SymbolCache[SymbolId]->clone())
+             : nullptr;
 }
 
 std::unique_ptr<PDBSymbol>