diff --git a/llvm/lib/Support/Signposts.cpp b/llvm/lib/Support/Signposts.cpp
new file mode 100644
index 0000000..d456f41
--- /dev/null
+++ b/llvm/lib/Support/Signposts.cpp
@@ -0,0 +1,119 @@
+//===-- Signposts.cpp - Interval debug annotations ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Signposts.h"
+#include "llvm/Support/Timer.h"
+
+#include "llvm/Config/config.h"
+#if LLVM_SUPPORT_XCODE_SIGNPOSTS
+#include "llvm/ADT/DenseMap.h"
+#include <os/signpost.h>
+#endif // if LLVM_SUPPORT_XCODE_SIGNPOSTS
+
+using namespace llvm;
+
+#if LLVM_SUPPORT_XCODE_SIGNPOSTS
+namespace {
+os_log_t *LogCreator() {
+  os_log_t *X = new os_log_t;
+  *X = os_log_create("org.llvm.signposts", OS_LOG_CATEGORY_POINTS_OF_INTEREST);
+  return X;
+}
+void LogDeleter(os_log_t *X) {
+  os_release(*X);
+  delete X;
+}
+} // end anonymous namespace
+
+namespace llvm {
+class SignpostEmitterImpl {
+  using LogPtrTy =
+      std::unique_ptr<os_log_t, std::function<void(os_log_t *)>>;
+  using LogTy = LogPtrTy::element_type;
+
+  LogPtrTy SignpostLog;
+  DenseMap<const Timer *, os_signpost_id_t> Signposts;
+
+  LogTy &getLogger() const { return *SignpostLog; }
+  os_signpost_id_t getSignpostForTimer(const Timer *T) {
+    const auto &I = Signposts.find(T);
+    if (I != Signposts.end())
+      return I->second;
+
+    const auto &Inserted = Signposts.insert(
+        std::make_pair(T, os_signpost_id_make_with_pointer(getLogger(), T)));
+    return Inserted.first->second;
+  }
+
+public:
+  SignpostEmitterImpl() : SignpostLog(LogCreator(), LogDeleter), Signposts() {}
+
+  bool isEnabled() const { return os_signpost_enabled(*SignpostLog); }
+
+  void startTimerInterval(Timer *T) {
+    if (isEnabled()) {
+      // Both strings used here are required to be constant literal strings
+      os_signpost_interval_begin(getLogger(), getSignpostForTimer(T),
+                                 "Pass Timers", "Begin %s",
+                                 T->getName().c_str());
+    }
+  }
+
+  void endTimerInterval(Timer *T) {
+    if (isEnabled()) {
+      // Both strings used here are required to be constant literal strings
+      os_signpost_interval_end(getLogger(), getSignpostForTimer(T),
+                               "Pass Timers", "End %s", T->getName().c_str());
+    }
+  }
+};
+} // end namespace llvm
+#endif // if LLVM_SUPPORT_XCODE_SIGNPOSTS
+
+#if LLVM_SUPPORT_XCODE_SIGNPOSTS
+#define HAVE_ANY_SIGNPOST_IMPL 1
+#endif
+
+SignpostEmitter::SignpostEmitter() {
+#if HAVE_ANY_SIGNPOST_IMPL
+  Impl = new SignpostEmitterImpl();
+#else // if HAVE_ANY_SIGNPOST_IMPL
+  Impl = nullptr;
+#endif // if !HAVE_ANY_SIGNPOST_IMPL
+}
+
+SignpostEmitter::~SignpostEmitter() {
+#if HAVE_ANY_SIGNPOST_IMPL
+  delete Impl;
+#endif // if HAVE_ANY_SIGNPOST_IMPL
+}
+
+bool SignpostEmitter::isEnabled() const {
+#if HAVE_ANY_SIGNPOST_IMPL
+  return Impl->isEnabled();
+#else
+  return false;
+#endif // if !HAVE_ANY_SIGNPOST_IMPL
+}
+
+void SignpostEmitter::startTimerInterval(Timer *T) {
+#if HAVE_ANY_SIGNPOST_IMPL
+  if (Impl == nullptr)
+    return;
+  return Impl->startTimerInterval(T);
+#endif // if !HAVE_ANY_SIGNPOST_IMPL
+}
+
+void SignpostEmitter::endTimerInterval(Timer *T) {
+#if HAVE_ANY_SIGNPOST_IMPL
+  if (Impl == nullptr)
+    return;
+  Impl->endTimerInterval(T);
+#endif // if !HAVE_ANY_SIGNPOST_IMPL
+}