--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/dsymutil/NonRelocatableStringpool.cpp	Wed Aug 14 16:55:33 2019 +0900
@@ -0,0 +1,56 @@
+//===- NonRelocatableStringpool.cpp - A simple stringpool  ----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "NonRelocatableStringpool.h"
+
+namespace llvm {
+namespace dsymutil {
+
+DwarfStringPoolEntryRef NonRelocatableStringpool::getEntry(StringRef S) {
+  if (S.empty() && !Strings.empty())
+    return EmptyString;
+
+  if (Translator)
+    S = Translator(S);
+  auto I = Strings.insert({S, DwarfStringPoolEntry()});
+  auto &Entry = I.first->second;
+  if (I.second || !Entry.isIndexed()) {
+    Entry.Index = NumEntries++;
+    Entry.Offset = CurrentEndOffset;
+    Entry.Symbol = nullptr;
+    CurrentEndOffset += S.size() + 1;
+  }
+  return DwarfStringPoolEntryRef(*I.first, true);
+}
+
+StringRef NonRelocatableStringpool::internString(StringRef S) {
+  DwarfStringPoolEntry Entry{nullptr, 0, DwarfStringPoolEntry::NotIndexed};
+
+  if (Translator)
+    S = Translator(S);
+
+  auto InsertResult = Strings.insert({S, Entry});
+  return InsertResult.first->getKey();
+}
+
+std::vector<DwarfStringPoolEntryRef>
+NonRelocatableStringpool::getEntriesForEmission() const {
+  std::vector<DwarfStringPoolEntryRef> Result;
+  Result.reserve(Strings.size());
+  for (const auto &E : Strings)
+    if (E.getValue().isIndexed())
+      Result.emplace_back(E, true);
+  llvm::sort(Result, [](const DwarfStringPoolEntryRef A,
+                        const DwarfStringPoolEntryRef B) {
+    return A.getIndex() < B.getIndex();
+  });
+  return Result;
+}
+
+} // namespace dsymutil
+} // namespace llvm