JMH Benchmark and passing java String to JExtracted Swift

Samples/SwiftKitSampleApp/Package.swift

@@ -60,6 +60,8 @@ let package = Package(
     .target(
       name: "MySwiftLibrary",
       dependencies: [
+        .product(name: "JavaKit", package: "swift-java"),
+        .product(name: "JavaRuntime", package: "swift-java"),
         .product(name: "SwiftKitSwift", package: "swift-java"),
       ],
       exclude: [

Samples/SwiftKitSampleApp/Sources/MySwiftLibrary/MySwiftLibrary.swift

@@ -31,6 +31,14 @@ public func globalTakeInt(i: Int) {
   p("i:\(i)")
 }
 
+public func globalMakeInt() -> Int {
+  return 42
+}
+
+public func globalWriteString(string: String) -> Int {
+  return string.count
+}
+
 public func globalTakeIntInt(i: Int, j: Int) {
   p("i:\(i), j:\(j)")
 }
@@ -79,6 +87,11 @@ public class MySwiftClass {
     return 12
   }
 
+  public func writeString(string: String) -> Int {
+    p("echo -> \(string)")
+    return string.count
+  }
+
   public func makeRandomIntMethod() -> Int {
     return Int.random(in: 1..<256)
   }
@@ -87,8 +100,8 @@ public class MySwiftClass {
 // ==== Internal helpers
 
 private func p(_ msg: String, file: String = #fileID, line: UInt = #line, function: String = #function) {
-  print("[swift][\(file):\(line)](\(function)) \(msg)")
-  fflush(stdout)
+//  print("[swift][\(file):\(line)](\(function)) \(msg)")
+//  fflush(stdout)
 }
 
 #if os(Linux)

Samples/SwiftKitSampleApp/Sources/MySwiftLibrary/jni/JNIImplementations.swift

@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import JavaKit
+import JavaRuntime
+
+@JavaClass("com.example.swift.HelloJava2Swift")
+open class HelloJava2Swift: JavaObject {
+}
+
+extension JavaClass<HelloJava2Swift> {
+}
+
+/// Describes the Java `native` methods for ``HelloJava2Swift``.
+///
+/// To implement all of the `native` methods for HelloSwift in Swift,
+/// extend HelloSwift to conform to this protocol and mark each
+/// implementation of the protocol requirement with `@JavaMethod`.
+protocol HelloJava2SwiftNativeMethods {
+  func jniWriteString(_ message: String) -> Int32
+  func jniGetInt() -> Int32
+}
+
+@JavaImplementation("com.example.swift.HelloJava2Swift")
+extension HelloJava2Swift: HelloJava2SwiftNativeMethods {
+  @JavaMethod
+  func jniWriteString(_ message: String) -> Int32 {
+    return Int32(message.count)
+  }
+
+  @JavaMethod
+  func jniGetInt() -> Int32 {
+    return 12
+  }
+}

Samples/SwiftKitSampleApp/build.gradle

@@ -145,10 +145,21 @@ application {
     ]
 }
 
+String jmhIncludes = findProperty("jmhIncludes")
+
 jmh {
+    if (jmhIncludes != null) {
+        includes = [jmhIncludes]
+    }
+
     jvmArgsAppend = [
+        "--enable-native-access=ALL-UNNAMED",
+
         "-Djava.library.path=" +
                 (BuildUtils.javaLibraryPaths(rootDir) +
                  BuildUtils.javaLibraryPaths(project.projectDir)).join(":"),
+
+        // Enable tracing downcalls (to Swift)
+        "-Djextract.trace.downcalls=false"
     ]
 }

Samples/SwiftKitSampleApp/src/jmh/java/org/swift/swiftkit/JavaToSwiftBenchmark.java

@@ -14,41 +14,51 @@
 
 package org.swift.swiftkit;
 
-import java.util.concurrent.TimeUnit;
-
-import org.openjdk.jmh.annotations.Benchmark;
-import org.openjdk.jmh.annotations.BenchmarkMode;
-import org.openjdk.jmh.annotations.Level;
-import org.openjdk.jmh.annotations.Mode;
-import org.openjdk.jmh.annotations.OutputTimeUnit;
-import org.openjdk.jmh.annotations.Scope;
-import org.openjdk.jmh.annotations.Setup;
-import org.openjdk.jmh.annotations.State;
-import org.openjdk.jmh.infra.Blackhole;
+import com.example.swift.HelloJava2Swift;
+import com.example.swift.MySwiftLibrary;
+import org.openjdk.jmh.annotations.*;
 
 import com.example.swift.MySwiftClass;
 
-@SuppressWarnings("unused")
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@Warmup(iterations = 5, time = 200, timeUnit = TimeUnit.MILLISECONDS)
+@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Fork(value = 3, jvmArgsAppend = { "--enable-native-access=ALL-UNNAMED" })
 public class JavaToSwiftBenchmark {
 
     @State(Scope.Benchmark)
     public static class BenchmarkState {
+        ClosableSwiftArena arena;
         MySwiftClass obj;
 
         @Setup(Level.Trial)
-        public void beforeALl() {
-            System.loadLibrary("swiftCore");
-            System.loadLibrary("ExampleSwiftLibrary");
-
-            // Tune down debug statements so they don't fill up stdout
-            System.setProperty("jextract.trace.downcalls", "false");
+        public void beforeAll() {
+            arena = SwiftArena.ofConfined();
+            obj = new MySwiftClass(arena, 1, 2);
+        }
 
-            obj = new MySwiftClass(1, 2);
+        @TearDown(Level.Trial)
+        public void afterAll() {
+            arena.close();
         }
     }
 
-    @Benchmark @BenchmarkMode(Mode.AverageTime) @OutputTimeUnit(TimeUnit.NANOSECONDS)
-    public void simpleSwiftApiCall(BenchmarkState state, Blackhole blackhole) {
-        blackhole.consume(state.obj.makeRandomIntMethod());
+    @Benchmark
+    public long jextract_getInt_ffm(BenchmarkState state) {
+        return MySwiftLibrary.globalMakeInt();
     }
+
+    @Benchmark
+    public long getInt_global_jni(BenchmarkState state) {
+        return HelloJava2Swift.jniGetInt();
+    }
+
+    @Benchmark
+    public long getInt_member_ffi(BenchmarkState state) {
+        return state.obj.makeIntMethod();
+    }
+
 }

Samples/SwiftKitSampleApp/src/jmh/java/org/swift/swiftkit/StringPassingBenchmark.java

@@ -0,0 +1,86 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+package org.swift.swiftkit;
+
+import com.example.swift.HelloJava2Swift;
+import com.example.swift.MySwiftClass;
+import com.example.swift.MySwiftLibrary;
+import org.openjdk.jmh.annotations.*;
+
+import java.lang.foreign.Arena;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@Warmup(iterations = 5, time = 200, timeUnit = TimeUnit.MILLISECONDS)
+@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Thread)
+@Fork(value = 2, jvmArgsAppend = {"--enable-native-access=ALL-UNNAMED"})
+public class StringPassingBenchmark {
+
+    @Param({
+            "5",
+            "10",
+            "100",
+            "200"
+    })
+    public int stringLen;
+    public String string;
+
+    ClosableSwiftArena arena;
+    MySwiftClass obj;
+
+    @Setup(Level.Trial)
+    public void beforeAll() {
+        arena = SwiftArena.ofConfined();
+        obj = new MySwiftClass(arena, 1, 2);
+        string = makeString(stringLen);
+    }
+
+    @TearDown(Level.Trial)
+    public void afterAll() {
+        arena.close();
+    }
+
+    @Benchmark
+    public long writeString_global_fmm() {
+        return MySwiftLibrary.globalWriteString(string);
+    }
+
+    @Benchmark
+    public long writeString_global_jni() {
+        return HelloJava2Swift.jniWriteString(string);
+    }
+
+    @Benchmark
+    public long writeString_baseline() {
+        return string.length();
+    }
+
+    static String makeString(int size) {
+        var text =
+                "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut in augue ullamcorper, mattis lacus tincidunt, " +
+                        "accumsan massa. Morbi gravida purus ut porttitor iaculis. Vestibulum lacinia, mi in tincidunt hendrerit," +
+                        "lectus est placerat magna, vitae vestibulum nulla ligula at massa. Pellentesque nibh quam, pulvinar eu " +
+                        "nunc congue, molestie molestie augue. Nam convallis consectetur velit, at dictum risus ullamcorper iaculis. " +
+                        "Vestibulum lacinia nisi in elit consectetur vulputate. Praesent id odio tristique, tincidunt arcu et, convallis velit. " +
+                        "Sed vitae pulvinar arcu. Curabitur euismod mattis dui in suscipit. Morbi aliquet facilisis vulputate. Phasellus " +
+                        "non lectus dapibus, semper magna eu, aliquet magna. Suspendisse vel enim at augue luctus gravida. Suspendisse " +
+                        "venenatis justo non accumsan sollicitudin. Suspendisse vitae ornare odio, id blandit nibh. Nulla facilisi. " +
+                        "Nulla nulla orci, finibus nec luctus et, faucibus et ligula.";
+        return text.substring(0, size);
+    }
+}

Samples/SwiftKitSampleApp/src/main/java/com/example/swift/HelloJava2Swift.java

@@ -56,4 +56,8 @@ static void examples() {
 
         System.out.println("DONE.");
     }
+
+    public static native long jniWriteString(String str);
+    public static native long jniGetInt();
+
 }

Samples/SwiftKitSampleApp/src/test/java/com/example/swift/MySwiftLibraryTest.java

@@ -14,6 +14,7 @@
 
 package com.example.swift;
 
+import com.example.swift.MySwiftLibrary;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
@@ -27,6 +28,10 @@
 
 public class MySwiftLibraryTest {
 
+    static {
+        System.loadLibrary(MySwiftLibrary.LIB_NAME);
+    }
+
     @Test
     void call_helloWorld() {
         MySwiftLibrary.helloWorld();
@@ -41,6 +46,22 @@ void call_globalTakeInt() {
         assertNotNull(MySwiftLibrary.globalTakeInt$address());
     }
 
+    @Test
+    void call_writeString_jextract() {
+        var string = "Hello Swift!";
+        long reply = MySwiftLibrary.globalWriteString(string);
+
+        assertEquals(string.length(), reply);
+    }
+
+    @Test
+    void call_writeString_jni() {
+        var string = "Hello Swift!";
+        long reply = HelloJava2Swift.jniWriteString(string);
+
+        assertEquals(string.length(), reply);
+    }
+
     @Test
     @Disabled("Upcalls not yet implemented in new scheme")
     @SuppressWarnings({"Convert2Lambda", "Convert2MethodRef"})

Sources/JExtractSwift/ImportedDecls.swift

@@ -90,6 +90,10 @@ public struct ImportedParam {
   var effectiveName: String? {
     firstName ?? secondName
   }
+
+  var effectiveValueName: String {
+    secondName ?? firstName ?? "_"
+  }
 
   // The Swift type as-is from the swift interface
   var swiftType: String {
@@ -113,6 +117,14 @@ extension ImportedParam {
   }
 }
 
+public enum ParameterVariant {
+  /// Used when declaring the "Swift thunks" we call through into Swift.
+  ///
+  /// Some types need to be represented as raw pointers and recovered into
+  /// Swift types inside the thunks when we do this.
+  case cDeclThunk
+}
+
 // TODO: this is used in different contexts and needs a cleanup
 //       Perhaps this is "which parameter passing style"?
 public enum SelfParameterVariant {

Sources/JExtractSwift/JavaTypes.swift

@@ -20,6 +20,11 @@ extension JavaType {
     .class(package: "java.lang.foreign", name: "MemorySegment")
   }
 
+  /// The description of the type java.lang.String.
+  static var javaLangString: JavaType {
+    .class(package: "java.lang", name: "String")
+  }
+
   /// The description of the type java.lang.Runnable.
   static var javaLangRunnable: JavaType {
     .class(package: "java.lang", name: "Runnable")