commit 367f3dd32454858b8b25d87feb8f6599d3b4c9dd
author Igor Murashkin <iam@google.com> Thu Sep 01 17:00:24 2016 -0700
committer Igor Murashkin <iam@google.com> Fri Sep 09 10:48:56 2016 -0700
tree 9fe45c9f6785c31918f70ed2d12683f9c8d702af
parent fa7b5c97db681e3d64d145807927cfafae78729b

jni: Add @CriticalNative optimization to speed up JNI transitions

Change-Id: I963059ac3a72dd8e6a867596c356d7062deb6da7

test/004-JniTest/jni_test.cc

diff --git a/test/004-JniTest/jni_test.cc b/test/004-JniTest/jni_test.cc
index bb18a70..81be531 100644
--- a/test/004-JniTest/jni_test.cc
+++ b/test/004-JniTest/jni_test.cc
@@ -28,9 +28,11 @@
 static JavaVM* jvm = nullptr;
 
 static jint Java_Main_intFastNativeMethod(JNIEnv*, jclass, jint a, jint b, jint c);
+static jint Java_Main_intCriticalNativeMethod(jint a, jint b, jint c);
 
 static JNINativeMethod sMainMethods[] = {
-  {"intFastNativeMethod", "(III)I", reinterpret_cast<void*>(Java_Main_intFastNativeMethod) }
+  {"intFastNativeMethod", "(III)I", reinterpret_cast<void*>(Java_Main_intFastNativeMethod) },
+  {"intCriticalNativeMethod", "(III)I", reinterpret_cast<void*>(Java_Main_intCriticalNativeMethod) },
 };
 
 extern "C" JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void*) {
@@ -766,5 +768,12 @@
   return a + b + c;
 }
 
+// Annotated with @CriticalNative in Java code. Doesn't need to be explicitly registered with "!".
+// NOTE: Has to be registered explicitly to avoid mutator lock check failures.
+static jint Java_Main_intCriticalNativeMethod(jint a, jint b, jint c) {
+  // Note that unlike a "Fast Native" method this excludes JNIEnv and the jclass parameters.
+  return a + b + c;
+}
+
 }  // namespace art
 

test/004-JniTest/src/Main.java

diff --git a/test/004-JniTest/src/Main.java b/test/004-JniTest/src/Main.java
index 573afdb..bb098e4 100644
--- a/test/004-JniTest/src/Main.java
+++ b/test/004-JniTest/src/Main.java
@@ -18,6 +18,7 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 
+import dalvik.annotation.optimization.CriticalNative;
 import dalvik.annotation.optimization.FastNative;
 
 public class Main {
@@ -49,6 +50,7 @@
 
         registerNativesJniTest();
         testFastNativeMethods();
+        testCriticalNativeMethods();
     }
 
     private static native boolean registerNativesJniTest();
@@ -288,7 +290,23 @@
       }
     }
 
+    // Smoke test for @CriticalNative
+    // TODO: Way more thorough tests since it involved quite a bit of changes.
 
+    // Return sum of a+b+c.
+    @CriticalNative
+    static native int intCriticalNativeMethod(int a, int b, int c);
+
+    private static void testCriticalNativeMethods() {
+      int returns[] = { 3, 6, 9, 12, 15 };
+      for (int i = 0; i < returns.length; i++) {
+        int result = intCriticalNativeMethod(i, i+1, i+2);
+        if (returns[i] != result) {
+          System.out.println("CriticalNative Int Run " + i + " with " + returns[i] + " vs " + result);
+          throw new AssertionError();
+        }
+      }
+    }
 }
 
 @FunctionalInterface