diff --git a/clang-tools-extra/clangd/SourceCode.h b/clang-tools-extra/clangd/SourceCode.h
new file mode 100644
index 0000000..2471a17
--- /dev/null
+++ b/clang-tools-extra/clangd/SourceCode.h
@@ -0,0 +1,29 @@
+//===--- SourceCode.h - Manipulating source code as strings -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Various code that examines C++ source code without using heavy AST machinery
+// (and often not even the lexer). To be used sparingly!
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_SOURCECODE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SOURCECODE_H
+#include "Protocol.h"
+
+namespace clang {
+namespace clangd {
+
+/// Turn a [line, column] pair into an offset in Code.
+size_t positionToOffset(llvm::StringRef Code, Position P);
+
+/// Turn an offset in Code into a [line, column] pair.
+Position offsetToPosition(llvm::StringRef Code, size_t Offset);
+
+} // namespace clangd
+} // namespace clang
+#endif