[String] Grapheme fast paths for punctuation: 5-8x speedup.

Many strings use non-sub-300 punctuation characters (e.g. unicode
hyphen, CJK quotes, etc). This can cause switching between fast and
slow paths for grapheme breaking. Add in fast-paths for general
punctuation characters and CJK punctuation and symbol characters.

This results in about a 5-8x speedup for heavily (unicode) punctuated
Latiny and CJKy workloads.

Author: milseman

benchmark/single-source/StringWalk.swift

@@ -16,15 +16,11 @@
 // scripts/generate_harness/generate_harness.py to regenerate this file.
 ////////////////////////////////////////////////////////////////////////////////
 
-
-// Test String subscript performance.
 //
-// Subscript has a slow path that initializes a global variable:
-// Swift._cocoaStringSubscript.addressor.  Global optimization would
-// normally hoist the initializer outside the inner loop (over
-// unicodeScalars), forcing the initializer to be called on each
-// lap. However, no that the cocoa code is properly marked "slowPath",
-// no hoisting should occur.
+// Test String iteration performance over a variety of workloads, languages,
+// and symbols.
+//
+
 import TestsUtils
 
 var count: Int = 0
@@ -70,6 +66,8 @@ let japanese = "今回のアップデートでSwiftに大幅な改良が施さ
 let chinese = "Swift 是面向 Apple 平台的编程语言，功能强大且直观易用，而本次更新对其进行了全面优化。"
 let korean = "이번 업데이트에서는 강력하면서도 직관적인 Apple 플랫폼용 프로그래밍 언어인 Swift를 완벽히 개선하였습니다."
 let russian = "в чащах юга жил-был цитрус? да, но фальшивый экземпляр"
+let punctuated = "\u{201c}Hello\u{2010}world\u{2026}\u{201d}"
+let punctuatedJapanese = "\u{300c}\u{300e}今日は\u{3001}世界\u{3002}\u{300f}\u{300d}"
 
 // A workload that's mostly Latin characters, with occasional emoji
 // interspersed. Common for tweets.
@@ -91,7 +89,6 @@ let unicodeScalarsMultiplier = baseMultiplier
 let charactersMultiplier = baseMultiplier / 5
 
 
-
 @inline(never)
 public func run_StringWalk_ascii_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -177,7 +174,6 @@ public func run_CharIndexing_ascii_unicodeScalars_Backwards(_ N: Int) {
 
 
 
-
 @inline(never)
 public func run_StringWalk_utf16_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -263,7 +259,6 @@ public func run_CharIndexing_utf16_unicodeScalars_Backwards(_ N: Int) {
 
 
 
-
 @inline(never)
 public func run_StringWalk_tweet_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -349,7 +344,6 @@ public func run_CharIndexing_tweet_unicodeScalars_Backwards(_ N: Int) {
 
 
 
-
 @inline(never)
 public func run_StringWalk_japanese_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -435,7 +429,6 @@ public func run_CharIndexing_japanese_unicodeScalars_Backwards(_ N: Int) {
 
 
 
-
 @inline(never)
 public func run_StringWalk_chinese_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -521,7 +514,6 @@ public func run_CharIndexing_chinese_unicodeScalars_Backwards(_ N: Int) {
 
 
 
-
 @inline(never)
 public func run_StringWalk_korean_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -607,7 +599,6 @@ public func run_CharIndexing_korean_unicodeScalars_Backwards(_ N: Int) {
 
 
 
-
 @inline(never)
 public func run_StringWalk_russian_unicodeScalars(_ N: Int) {
   for _ in 1...unicodeScalarsMultiplier*N {
@@ -692,3 +683,173 @@ public func run_CharIndexing_russian_unicodeScalars_Backwards(_ N: Int) {
 
 
 
+
+@inline(never)
+public func run_StringWalk_punctuated_unicodeScalars(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    count_unicodeScalars(punctuated.unicodeScalars)
+  }
+}
+
+@inline(never)
+public func run_StringWalk_punctuated_unicodeScalars_Backwards(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    count_unicodeScalars_rev(punctuated.unicodeScalars.reversed())
+  }
+}
+
+
+
+
+@inline(never)
+public func run_StringWalk_punctuated_characters(_ N: Int) {
+  for _ in 1...charactersMultiplier*N {
+    count_characters(punctuated.characters)
+  }
+}
+
+@inline(never)
+public func run_StringWalk_punctuated_characters_Backwards(_ N: Int) {
+  for _ in 1...charactersMultiplier*N {
+    count_characters_rev(punctuated.characters.reversed())
+  }
+}
+
+
+
+
+let punctuatedCharacters = Array(punctuated)
+
+@inline(never)
+public func run_CharIteration_punctuated_unicodeScalars(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedCharacters {
+      for u in c.unicodeScalars {
+        count |= Int(u.value)
+      }
+    }
+  }
+}
+
+@inline(never)
+public func run_CharIteration_punctuated_unicodeScalars_Backwards(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedCharacters {
+      for u in c.unicodeScalars.reversed() {
+        count |= Int(u.value)
+      }
+    }
+  }
+}
+
+@inline(never)
+public func run_CharIndexing_punctuated_unicodeScalars(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedCharacters {
+      let s = c.unicodeScalars
+      for i in s.indices {
+        count |= Int(s[i].value)
+      }
+    }
+  }
+}
+
+@inline(never)
+public func run_CharIndexing_punctuated_unicodeScalars_Backwards(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedCharacters {
+      let s = c.unicodeScalars
+      for i in s.indices.reversed() {
+        count |= Int(s[i].value)
+      }
+    }
+  }
+}
+
+
+
+
+@inline(never)
+public func run_StringWalk_punctuatedJapanese_unicodeScalars(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    count_unicodeScalars(punctuatedJapanese.unicodeScalars)
+  }
+}
+
+@inline(never)
+public func run_StringWalk_punctuatedJapanese_unicodeScalars_Backwards(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    count_unicodeScalars_rev(punctuatedJapanese.unicodeScalars.reversed())
+  }
+}
+
+
+
+
+@inline(never)
+public func run_StringWalk_punctuatedJapanese_characters(_ N: Int) {
+  for _ in 1...charactersMultiplier*N {
+    count_characters(punctuatedJapanese.characters)
+  }
+}
+
+@inline(never)
+public func run_StringWalk_punctuatedJapanese_characters_Backwards(_ N: Int) {
+  for _ in 1...charactersMultiplier*N {
+    count_characters_rev(punctuatedJapanese.characters.reversed())
+  }
+}
+
+
+
+
+let punctuatedJapaneseCharacters = Array(punctuatedJapanese)
+
+@inline(never)
+public func run_CharIteration_punctuatedJapanese_unicodeScalars(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedJapaneseCharacters {
+      for u in c.unicodeScalars {
+        count |= Int(u.value)
+      }
+    }
+  }
+}
+
+@inline(never)
+public func run_CharIteration_punctuatedJapanese_unicodeScalars_Backwards(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedJapaneseCharacters {
+      for u in c.unicodeScalars.reversed() {
+        count |= Int(u.value)
+      }
+    }
+  }
+}
+
+@inline(never)
+public func run_CharIndexing_punctuatedJapanese_unicodeScalars(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedJapaneseCharacters {
+      let s = c.unicodeScalars
+      for i in s.indices {
+        count |= Int(s[i].value)
+      }
+    }
+  }
+}
+
+@inline(never)
+public func run_CharIndexing_punctuatedJapanese_unicodeScalars_Backwards(_ N: Int) {
+  for _ in 1...unicodeScalarsMultiplier*N {
+    for c in punctuatedJapaneseCharacters {
+      let s = c.unicodeScalars
+      for i in s.indices.reversed() {
+        count |= Int(s[i].value)
+      }
+    }
+  }
+}
+
+
+

benchmark/single-source/StringWalk.swift.gyb

@@ -17,15 +17,11 @@
 // scripts/generate_harness/generate_harness.py to regenerate this file.
 ////////////////////////////////////////////////////////////////////////////////
 
-
-// Test String subscript performance.
 //
-// Subscript has a slow path that initializes a global variable:
-// Swift._cocoaStringSubscript.addressor.  Global optimization would
-// normally hoist the initializer outside the inner loop (over
-// unicodeScalars), forcing the initializer to be called on each
-// lap. However, no that the cocoa code is properly marked "slowPath",
-// no hoisting should occur.
+// Test String iteration performance over a variety of workloads, languages,
+// and symbols.
+//
+
 import TestsUtils
 
 var count: Int = 0
@@ -71,6 +67,8 @@ let japanese = "今回のアップデートでSwiftに大幅な改良が施さ
 let chinese = "Swift 是面向 Apple 平台的编程语言，功能强大且直观易用，而本次更新对其进行了全面优化。"
 let korean = "이번 업데이트에서는 강력하면서도 직관적인 Apple 플랫폼용 프로그래밍 언어인 Swift를 완벽히 개선하였습니다."
 let russian = "в чащах юга жил-был цитрус? да, но фальшивый экземпляр"
+let punctuated = "\u{201c}Hello\u{2010}world\u{2026}\u{201d}"
+let punctuatedJapanese = "\u{300c}\u{300e}今日は\u{3001}世界\u{3002}\u{300f}\u{300d}"
 
 // A workload that's mostly Latin characters, with occasional emoji
 // interspersed. Common for tweets.
@@ -91,8 +89,7 @@ let baseMultiplier = 10_000
 let unicodeScalarsMultiplier = baseMultiplier
 let charactersMultiplier = baseMultiplier / 5
 
-% for Name in ["ascii", "utf16", "tweet", "japanese", "chinese", "korean", "russian"]:
-
+% for Name in ["ascii", "utf16", "tweet", "japanese", "chinese", "korean", "russian", "punctuated", "punctuatedJapanese"]:
 %   for Kind in ["unicodeScalars", "characters"]:
 
 @inline(never)

benchmark/utils/main.swift

@@ -178,6 +178,10 @@ addTo(&precommitTests, "CharIndexing_japanese_unicodeScalars", run_CharIndexing_
 addTo(&precommitTests, "CharIndexing_japanese_unicodeScalars_Backwards", run_CharIndexing_japanese_unicodeScalars_Backwards)
 addTo(&precommitTests, "CharIndexing_korean_unicodeScalars", run_CharIndexing_korean_unicodeScalars)
 addTo(&precommitTests, "CharIndexing_korean_unicodeScalars_Backwards", run_CharIndexing_korean_unicodeScalars_Backwards)
+addTo(&precommitTests, "CharIndexing_punctuatedJapanese_unicodeScalars", run_CharIndexing_punctuatedJapanese_unicodeScalars)
+addTo(&precommitTests, "CharIndexing_punctuatedJapanese_unicodeScalars_Backwards", run_CharIndexing_punctuatedJapanese_unicodeScalars_Backwards)
+addTo(&precommitTests, "CharIndexing_punctuated_unicodeScalars", run_CharIndexing_punctuated_unicodeScalars)
+addTo(&precommitTests, "CharIndexing_punctuated_unicodeScalars_Backwards", run_CharIndexing_punctuated_unicodeScalars_Backwards)
 addTo(&precommitTests, "CharIndexing_russian_unicodeScalars", run_CharIndexing_russian_unicodeScalars)
 addTo(&precommitTests, "CharIndexing_russian_unicodeScalars_Backwards", run_CharIndexing_russian_unicodeScalars_Backwards)
 addTo(&precommitTests, "CharIndexing_tweet_unicodeScalars", run_CharIndexing_tweet_unicodeScalars)
@@ -192,6 +196,10 @@ addTo(&precommitTests, "CharIteration_japanese_unicodeScalars", run_CharIteratio
 addTo(&precommitTests, "CharIteration_japanese_unicodeScalars_Backwards", run_CharIteration_japanese_unicodeScalars_Backwards)
 addTo(&precommitTests, "CharIteration_korean_unicodeScalars", run_CharIteration_korean_unicodeScalars)
 addTo(&precommitTests, "CharIteration_korean_unicodeScalars_Backwards", run_CharIteration_korean_unicodeScalars_Backwards)
+addTo(&precommitTests, "CharIteration_punctuatedJapanese_unicodeScalars", run_CharIteration_punctuatedJapanese_unicodeScalars)
+addTo(&precommitTests, "CharIteration_punctuatedJapanese_unicodeScalars_Backwards", run_CharIteration_punctuatedJapanese_unicodeScalars_Backwards)
+addTo(&precommitTests, "CharIteration_punctuated_unicodeScalars", run_CharIteration_punctuated_unicodeScalars)
+addTo(&precommitTests, "CharIteration_punctuated_unicodeScalars_Backwards", run_CharIteration_punctuated_unicodeScalars_Backwards)
 addTo(&precommitTests, "CharIteration_russian_unicodeScalars", run_CharIteration_russian_unicodeScalars)
 addTo(&precommitTests, "CharIteration_russian_unicodeScalars_Backwards", run_CharIteration_russian_unicodeScalars_Backwards)
 addTo(&precommitTests, "CharIteration_tweet_unicodeScalars", run_CharIteration_tweet_unicodeScalars)
@@ -563,6 +571,14 @@ addTo(&stringTests, "StringWalk_korean_characters", run_StringWalk_korean_charac
 addTo(&stringTests, "StringWalk_korean_characters_Backwards", run_StringWalk_korean_characters_Backwards)
 addTo(&stringTests, "StringWalk_korean_unicodeScalars", run_StringWalk_korean_unicodeScalars)
 addTo(&stringTests, "StringWalk_korean_unicodeScalars_Backwards", run_StringWalk_korean_unicodeScalars_Backwards)
+addTo(&stringTests, "StringWalk_punctuatedJapanese_characters", run_StringWalk_punctuatedJapanese_characters)
+addTo(&stringTests, "StringWalk_punctuatedJapanese_characters_Backwards", run_StringWalk_punctuatedJapanese_characters_Backwards)
+addTo(&stringTests, "StringWalk_punctuatedJapanese_unicodeScalars", run_StringWalk_punctuatedJapanese_unicodeScalars)
+addTo(&stringTests, "StringWalk_punctuatedJapanese_unicodeScalars_Backwards", run_StringWalk_punctuatedJapanese_unicodeScalars_Backwards)
+addTo(&stringTests, "StringWalk_punctuated_characters", run_StringWalk_punctuated_characters)
+addTo(&stringTests, "StringWalk_punctuated_characters_Backwards", run_StringWalk_punctuated_characters_Backwards)
+addTo(&stringTests, "StringWalk_punctuated_unicodeScalars", run_StringWalk_punctuated_unicodeScalars)
+addTo(&stringTests, "StringWalk_punctuated_unicodeScalars_Backwards", run_StringWalk_punctuated_unicodeScalars_Backwards)
 addTo(&stringTests, "StringWalk_russian_characters", run_StringWalk_russian_characters)
 addTo(&stringTests, "StringWalk_russian_characters_Backwards", run_StringWalk_russian_characters_Backwards)
 addTo(&stringTests, "StringWalk_russian_unicodeScalars", run_StringWalk_russian_unicodeScalars)

stdlib/public/core/StringCharacterView.swift

@@ -344,6 +344,14 @@ extension String.CharacterView : BidirectionalCollection {
       //   0xAC00–0xD7AF
       case 0xac00...0xd7af: return true
 
+      // Common general use punctuation, excluding extenders:
+      //   0x2010-0x2029
+      case 0x2010...0x2029: return true
+
+      // CJK punctuation characters, excluding extenders:
+      //   0x3000-0x3029
+      case 0x3000...0x3029: return true
+
       default: return false
       }
     }