diff --git a/src/llvm-project/lldb/source/Utility/StringLexer.cpp b/src/llvm-project/lldb/source/Utility/StringLexer.cpp
new file mode 100644
index 0000000..d5c7fc6
--- /dev/null
+++ b/src/llvm-project/lldb/source/Utility/StringLexer.cpp
@@ -0,0 +1,88 @@
+//===--------------------- StringLexer.cpp -----------------------*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Utility/StringLexer.h"
+
+#include <algorithm>
+#include <assert.h>
+
+using namespace lldb_utility;
+
+StringLexer::StringLexer(std::string s) : m_data(s), m_position(0) {}
+
+StringLexer::StringLexer(const StringLexer &rhs)
+    : m_data(rhs.m_data), m_position(rhs.m_position) {}
+
+StringLexer::Character StringLexer::Peek() { return m_data[m_position]; }
+
+bool StringLexer::NextIf(Character c) {
+  auto val = Peek();
+  if (val == c) {
+    Next();
+    return true;
+  }
+  return false;
+}
+
+std::pair<bool, StringLexer::Character>
+StringLexer::NextIf(std::initializer_list<Character> cs) {
+  auto val = Peek();
+  for (auto c : cs) {
+    if (val == c) {
+      Next();
+      return {true, c};
+    }
+  }
+  return {false, 0};
+}
+
+bool StringLexer::AdvanceIf(const std::string &token) {
+  auto pos = m_position;
+  bool matches = true;
+  for (auto c : token) {
+    if (!NextIf(c)) {
+      matches = false;
+      break;
+    }
+  }
+  if (!matches) {
+    m_position = pos;
+    return false;
+  }
+  return true;
+}
+
+StringLexer::Character StringLexer::Next() {
+  auto val = Peek();
+  Consume();
+  return val;
+}
+
+bool StringLexer::HasAtLeast(Size s) {
+  return (m_data.size() - m_position) >= s;
+}
+
+void StringLexer::PutBack(Size s) {
+  assert(m_position >= s);
+  m_position -= s;
+}
+
+std::string StringLexer::GetUnlexed() {
+  return std::string(m_data, m_position);
+}
+
+void StringLexer::Consume() { m_position++; }
+
+StringLexer &StringLexer::operator=(const StringLexer &rhs) {
+  if (this != &rhs) {
+    m_data = rhs.m_data;
+    m_position = rhs.m_position;
+  }
+  return *this;
+}