ART: Add GetObjectSize and GetObjectHashCode

Add support for these two functions. Add tests.

Bug: 31684578
Test: m test-art-host-run-test-920-objects
Change-Id: If5dfb5aedddee47e5d739b0c56c7d264ba6e2d51
diff --git a/test/920-objects/src/Main.java b/test/920-objects/src/Main.java
new file mode 100644
index 0000000..5dbe1a7
--- /dev/null
+++ b/test/920-objects/src/Main.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Field;
+import java.util.Arrays;
+
+public class Main {
+  public static void main(String[] args) throws Exception {
+    System.loadLibrary(args[1]);
+
+    doTest();
+  }
+
+  public static void doTest() throws Exception {
+    testObjectSize(new Object());
+    testObjectSize(new Object());
+
+    testObjectSize(new int[0]);
+    testObjectSize(new int[1]);
+    testObjectSize(new int[2]);
+
+    testObjectSize(new double[0]);
+    testObjectSize(new double[1]);
+    testObjectSize(new double[2]);
+
+    testObjectSize(new String("abc"));
+    testObjectSize(new String("wxyz"));
+
+    testObjectHash();
+  }
+
+  private static void testObjectSize(Object o) {
+    System.out.println(o.getClass() + " " + getObjectSize(o));
+  }
+
+  private static void testObjectHash() {
+    Object[] objects = new Object[] {
+        new Object(),
+        new Object(),
+
+        new MyHash(1),
+        new MyHash(1),
+        new MyHash(2)
+    };
+
+    int hashes[] = new int[objects.length];
+
+    for (int i = 0; i < objects.length; i++) {
+      hashes[i] = getObjectHashCode(objects[i]);
+    }
+
+    // Implementation detail: we use the identity hashcode, for simplicity.
+    for (int i = 0; i < objects.length; i++) {
+      int ihash = System.identityHashCode(objects[i]);
+      if (hashes[i] != ihash) {
+        throw new RuntimeException(objects[i] + ": " + hashes[i] + " vs " + ihash);
+      }
+    }
+
+    Runtime.getRuntime().gc();
+    Runtime.getRuntime().gc();
+
+    for (int i = 0; i < objects.length; i++) {
+      int newhash = getObjectHashCode(objects[i]);
+      if (hashes[i] != newhash) {
+        throw new RuntimeException(objects[i] + ": " + hashes[i] + " vs " + newhash);
+      }
+    }
+  }
+
+  private static native long getObjectSize(Object o);
+  private static native int getObjectHashCode(Object o);
+
+  private static class MyHash {
+    private int hash;
+
+    public MyHash(int h) {
+      hash = h;
+    }
+
+    public int hashCode() {
+      return hash;
+    }
+  }
+}