--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/lib/Testing/Support/Annotations.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,95 @@
+//===--- Annotations.cpp - Annotated source code for unit tests --*- C++-*-===//
+//
+// 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 "llvm/Testing/Support/Annotations.h"
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+// Crash if the assertion fails, printing the message and testcase.
+// More elegant error handling isn't needed for unit tests.
+static void require(bool Assertion, const char *Msg, llvm::StringRef Code) {
+  if (!Assertion) {
+    llvm::errs() << "Annotated testcase: " << Msg << "\n" << Code << "\n";
+    llvm_unreachable("Annotated testcase assertion failed!");
+  }
+}
+
+Annotations::Annotations(llvm::StringRef Text) {
+  auto Require = [Text](bool Assertion, const char *Msg) {
+    require(Assertion, Msg, Text);
+  };
+  llvm::Optional<llvm::StringRef> Name;
+  llvm::SmallVector<std::pair<llvm::StringRef, size_t>, 8> OpenRanges;
+
+  Code.reserve(Text.size());
+  while (!Text.empty()) {
+    if (Text.consume_front("^")) {
+      Points[Name.getValueOr("")].push_back(Code.size());
+      Name = llvm::None;
+      continue;
+    }
+    if (Text.consume_front("[[")) {
+      OpenRanges.emplace_back(Name.getValueOr(""), Code.size());
+      Name = llvm::None;
+      continue;
+    }
+    Require(!Name, "$name should be followed by ^ or [[");
+    if (Text.consume_front("]]")) {
+      Require(!OpenRanges.empty(), "unmatched ]]");
+      Range R;
+      R.Begin = OpenRanges.back().second;
+      R.End = Code.size();
+      Ranges[OpenRanges.back().first].push_back(R);
+      OpenRanges.pop_back();
+      continue;
+    }
+    if (Text.consume_front("$")) {
+      Name = Text.take_while(llvm::isAlnum);
+      Text = Text.drop_front(Name->size());
+      continue;
+    }
+    Code.push_back(Text.front());
+    Text = Text.drop_front();
+  }
+  Require(!Name, "unterminated $name");
+  Require(OpenRanges.empty(), "unmatched [[");
+}
+
+size_t Annotations::point(llvm::StringRef Name) const {
+  auto I = Points.find(Name);
+  require(I != Points.end() && I->getValue().size() == 1,
+          "expected exactly one point", Code);
+  return I->getValue()[0];
+}
+
+std::vector<size_t> Annotations::points(llvm::StringRef Name) const {
+  auto P = Points.lookup(Name);
+  return {P.begin(), P.end()};
+}
+
+Annotations::Range Annotations::range(llvm::StringRef Name) const {
+  auto I = Ranges.find(Name);
+  require(I != Ranges.end() && I->getValue().size() == 1,
+          "expected exactly one range", Code);
+  return I->getValue()[0];
+}
+
+std::vector<Annotations::Range>
+Annotations::ranges(llvm::StringRef Name) const {
+  auto R = Ranges.lookup(Name);
+  return {R.begin(), R.end()};
+}
+
+llvm::raw_ostream &llvm::operator<<(llvm::raw_ostream &O,
+                                    const llvm::Annotations::Range &R) {
+  return O << llvm::formatv("[{0}, {1})", R.Begin, R.End);
+}