Add benchmark for devirtualization performance measurements

Author: zoecarver

benchmark/CMakeLists.txt

@@ -62,6 +62,7 @@ set(SWIFT_BENCH_MODULES
     single-source/Combos
     single-source/DataBenchmarks
     single-source/DeadArray
+    single-source/DevirtualizeProtocolComposition
     single-source/DictOfArraysToArrayOfDicts
     single-source/DictTest
     single-source/DictTest2

benchmark/single-source/DevirtualizeProtocolComposition.swift

@@ -0,0 +1,65 @@
+//===--- DevirtualizeProtocolComposition.swift -------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 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 let DevirtualizeProtocolComposition = [
+  BenchmarkInfo(name: "DevirtualizeProtocolComposition", runFunction: run_DevirtualizeProtocolComposition, tags: [.validation, .api]),
+]
+
+public class ClassA<T> { }
+
+protocol ProtocolA {
+  func foo() -> Int
+}
+
+protocol ProtocolB {
+  func bar() -> Int
+}
+
+public class ClassB: ClassA<String> {
+  func foo() -> Int {
+    return 10
+  }
+}
+
+extension ClassB: ProtocolA { }
+
+func quadratic(a: Int) -> Int {
+  var sum = 0
+  for _ in 0..<a {
+    for _ in 0..<a {
+      sum += 1
+    }
+  }
+  return sum
+}
+
+func shouldOptimize1<T>(_ x: ClassA<T> & ProtocolA, count: Int) -> Int {
+  var sum = 0
+  for _ in 0..<count {
+    sum += quadratic(a: x.foo())
+  }
+  return sum
+}
+
+@inline(never)
+public func entryPoint1(c: ClassB) -> Int {
+  return shouldOptimize1(c, count: 25)
+}
+
+@inline(never)
+public func run_DevirtualizeProtocolComposition(N: Int) {
+  for _ in 0..<N * 10_000 {
+    entryPoint1(c: ClassB())
+  }
+}

benchmark/utils/main.swift

@@ -50,6 +50,7 @@ import Codable
 import Combos
 import DataBenchmarks
 import DeadArray
+import DevirtualizeProtocolComposition
 import DictOfArraysToArrayOfDicts
 import DictTest
 import DictTest2
@@ -231,6 +232,7 @@ registerBenchmark(Combos)
 registerBenchmark(ClassArrayGetter)
 registerBenchmark(DataBenchmarks)
 registerBenchmark(DeadArray)
+registerBenchmark(DevirtualizeProtocolComposition)
 registerBenchmark(DictOfArraysToArrayOfDicts)
 registerBenchmark(Dictionary)
 registerBenchmark(Dictionary2)