[benchmark] Add a basic benchmark for Unicode._CharacterRecognizer

This measures the performance of the stdlib’s core grapheme breaking algorithm, without any `String` overhead.

benchmark/CMakeLists.txt

@@ -57,6 +57,7 @@ set(SWIFT_BENCH_MODULES
     single-source/CharacterLiteralsLarge
     single-source/CharacterLiteralsSmall
     single-source/CharacterProperties
+    single-source/CharacterRecognizer
     single-source/Chars
     single-source/ClassArrayGetter
     single-source/CodableTest

benchmark/single-source/CharacterRecognizer.swift

@@ -0,0 +1,97 @@
+//===--- StringEdits.swift ------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import TestsUtils
+
+public var benchmarks: [BenchmarkInfo] {
+  guard #available(macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, *) else {
+    return []
+  }
+  return [
+    BenchmarkInfo(
+      name: "CharacterRecognizer.mixed",
+      runFunction: { n in
+        run(string: mixedString, n: n)
+      },
+      tags: [.api, .String],
+      setUpFunction: { blackHole(mixedString) }),
+    BenchmarkInfo(
+      name: "CharacterRecognizer.ascii",
+      runFunction: { n in
+        run(string: asciiString, n: n)
+      },
+      tags: [.api, .String],
+      setUpFunction: { blackHole(asciiString) }),
+  ]
+}
+
+let mixedString = #"""
+    The powerful programming language that is also easy to learn.
+    손쉽게 학습할 수 있는 강력한 프로그래밍 언어.
+    🪙 A 🥞 short 🍰 piece 🫘 of 🌰 text 👨‍👨‍👧‍👧 with 👨‍👩‍👦 some 🚶🏽 emoji 🇺🇸🇨🇦 characters 🧈
+    some🔩times 🛺 placed 🎣 in 🥌 the 🆘 mid🔀dle 🇦🇶or🏁 around 🏳️‍🌈 a 🍇 w🍑o🥒r🥨d
+    Unicode is such fun!
+    U̷n̷i̷c̷o̴d̴e̷ ̶i̸s̷ ̸s̵u̵c̸h̷ ̸f̵u̷n̴!̵
+    U̴̡̲͋̾n̵̻̳͌ì̶̠̕c̴̭̈͘ǫ̷̯͋̊d̸͖̩̈̈́ḛ̴́ ̴̟͎͐̈i̴̦̓s̴̜̱͘ ̶̲̮̚s̶̙̞͘u̵͕̯̎̽c̵̛͕̜̓h̶̘̍̽ ̸̜̞̿f̵̤̽ṷ̴͇̎͘ń̷͓̒!̷͍̾̚
+    U̷̢̢̧̨̼̬̰̪͓̞̠͔̗̼̙͕͕̭̻̗̮̮̥̣͉̫͉̬̲̺͍̺͊̂ͅ\#
+    n̶̨̢̨̯͓̹̝̲̣̖̞̼̺̬̤̝̊̌́̑̋̋͜͝ͅ\#
+    ḭ̸̦̺̺͉̳͎́͑\#
+    c̵̛̘̥̮̙̥̟̘̝͙̤̮͉͔̭̺̺̅̀̽̒̽̏̊̆͒͌̂͌̌̓̈́̐̔̿̂͑͠͝͝ͅ\#
+    ö̶̱̠̱̤̙͚͖̳̜̰̹̖̣̻͎͉̞̫̬̯͕̝͔̝̟̘͔̙̪̭̲́̆̂͑̌͂̉̀̓́̏̎̋͗͛͆̌̽͌̄̎̚͝͝͝͝ͅ\#
+    d̶̨̨̡̡͙̟͉̱̗̝͙͍̮͍̘̮͔͑\#
+    e̶̢͕̦̜͔̘̘̝͈̪̖̺̥̺̹͉͎͈̫̯̯̻͑͑̿̽͂̀̽͋́̎̈́̈̿͆̿̒̈́̽̔̇͐͛̀̓͆̏̾̀̌̈́̆̽̕ͅ
+    """#
+
+let _asciiString = #"""
+  Swift is a high-performance system programming language.  It has a clean
+  and modern syntax, offers seamless access to existing C and Objective-C code
+  and frameworks, and is memory safe by default.
+
+  Although inspired by Objective-C and many other languages, Swift is not itself
+  a C-derived language. As a complete and independent language, Swift packages
+  core features like flow control, data structures, and functions, with
+  high-level constructs like objects, protocols, closures, and generics. Swift
+  embraces modules, eliminating the need for headers and the code duplication
+  they entail.
+
+  Swift toolchains are created using the script
+  [build-toolchain](https://github.com/apple/swift/blob/main/utils/build-toolchain).
+  This script is used by swift.org's CI to produce snapshots and can allow for
+  one to locally reproduce such builds for development or distribution purposes.
+  A typical invocation looks like the following:
+
+  ```
+    $ ./swift/utils/build-toolchain $BUNDLE_PREFIX
+  ```
+
+  where ``$BUNDLE_PREFIX`` is a string that will be prepended to the build date
+  to give the bundle identifier of the toolchain's ``Info.plist``. For instance,
+  if ``$BUNDLE_PREFIX`` was ``com.example``, the toolchain produced will have
+  the bundle identifier ``com.example.YYYYMMDD``. It will be created in the
+  directory you run the script with a filename of the form:
+  ``swift-LOCAL-YYYY-MM-DD-a-osx.tar.gz``.
+  """#
+let asciiString = String(repeating: _asciiString, count: 10)
+
+@available(macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, *)
+func run(string: String, n: Int) {
+  var state = Unicode._CharacterRecognizer()
+  var c = 0
+  for _ in 0 ..< n {
+    for scalar in string.unicodeScalars {
+      if state.hasBreak(before: scalar) {
+        c += 1
+      }
+    }
+  }
+  blackHole(c)
+}

benchmark/utils/main.swift

@@ -45,6 +45,7 @@ import ChainedFilterMap
 import CharacterLiteralsLarge
 import CharacterLiteralsSmall
 import CharacterProperties
+import CharacterRecognizer
 import Chars
 import ClassArrayGetter
 import CodableTest
@@ -230,6 +231,7 @@ register(ChainedFilterMap.benchmarks)
 register(CharacterLiteralsLarge.benchmarks)
 register(CharacterLiteralsSmall.benchmarks)
 register(CharacterProperties.benchmarks)
+register(CharacterRecognizer.benchmarks)
 register(Chars.benchmarks)
 register(CodableTest.benchmarks)
 register(Combos.benchmarks)