Test for static field VarHandle and class unloading.

Test: Additional test in 710-varhandle-creation
Test: testrunner.py --host --optimizing -t 710-varhandle-creation
Bug: 191980149
Change-Id: I95b7d8c435fcf5286a57bba3d4877dfac65b5771

4 files changed, 85 insertions, 0 deletions

diff --git a/test/710-varhandle-creation/expected-stdout.txt b/test/710-varhandle-creation/expected-stdout.txt
index 89dfb48245..7c858a68ac 100644
--- a/test/710-varhandle-creation/expected-stdout.txt
+++ b/test/710-varhandle-creation/expected-stdout.txt
@@ -4,3 +4,5 @@ LookupCheckA...PASS
 LookupCheckB...PASS
 UnreflectCheck...PASS
 LookupCheckC...PASS
+Initial value of UnloadTest.i: 42
+Final value of UnloadTest.i: 42
diff --git a/test/710-varhandle-creation/run b/test/710-varhandle-creation/run
new file mode 100644
index 0000000000..46b1a8308b
--- /dev/null
+++ b/test/710-varhandle-creation/run
@@ -0,0 +1,18 @@
+#!/bin/bash
+#
+# Copyright (C) 2021 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.
+
+# Currently app images aren't unloaded when dex files are unloaded.
+exec ${RUN} $@ --no-secondary-app-image
diff --git a/test/710-varhandle-creation/src-ex/UnloadTest.java b/test/710-varhandle-creation/src-ex/UnloadTest.java
new file mode 100644
index 0000000000..f6d366ace0
--- /dev/null
+++ b/test/710-varhandle-creation/src-ex/UnloadTest.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+public class UnloadTest {
+    public static int i = 42;
+}
diff --git a/test/710-varhandle-creation/src/Main.java b/test/710-varhandle-creation/src/Main.java
index 246aac6900..c4fe2ffed1 100644
--- a/test/710-varhandle-creation/src/Main.java
+++ b/test/710-varhandle-creation/src/Main.java
@@ -17,6 +17,7 @@
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.VarHandle;
 import java.lang.invoke.VarHandle.AccessMode;
+import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.nio.ByteOrder;
 import java.util.ArrayList;
@@ -2401,6 +2402,50 @@ public final class Main {
         }
     }
 
+    private static ClassLoader createExClassLoader() throws Exception {
+        String location = System.getenv("DEX_LOCATION");
+        try {
+            Class<?> class_loader_class = Class.forName("dalvik.system.PathClassLoader");
+            Constructor<?> ctor =
+                    class_loader_class.getConstructor(String.class, ClassLoader.class);
+
+            return (ClassLoader)ctor.newInstance(location + "/710-varhandle-creation-ex.jar",
+                                                 Main.class.getClassLoader());
+        } catch (ClassNotFoundException e) {
+            // Running on RI. Use URLClassLoader.
+            return new java.net.URLClassLoader(
+                    new java.net.URL[] { new java.net.URL("file://" + location + "/classes-ex/") });
+        }
+    }
+
+    private static Class<?> loadUnloadTestClass() throws Exception {
+        ClassLoader loader = createExClassLoader();
+        return Class.forName("UnloadTest", true, loader);
+    }
+
+    private static VarHandle createUnloadTestVarHandle() throws Exception {
+        Class<?> klass = loadUnloadTestClass();
+        return MethodHandles.lookup().findStaticVarHandle(klass, "i", int.class);
+    }
+
+    // Regression test for static field VarHandle previously not keeping
+    // the target class alive, leading to a crash. Bug: 191980149
+    private static void checkStaticFieldVarHandleGc() {
+        try {
+            VarHandle vh = createUnloadTestVarHandle();
+            // Print the initial value.
+            System.out.println("Initial value of UnloadTest.i: " + (int) vh.get());
+            // Try to collect all garbage thoroughly.
+            for (int i = 0; i < 5; ++i) {
+               Runtime.getRuntime().gc();
+            }
+            // Print the value again.
+            System.out.println("Final value of UnloadTest.i: " + (int) vh.get());
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     public static void main(String[] args) {
         checkAccessModes();
         checkInstantiatedVarHandles();
@@ -2408,6 +2453,7 @@ public final class Main {
         LookupCheckB.run();
         LookupCheckC.run();
         UnreflectCheck.run();
+        checkStaticFieldVarHandleGc();
     }
 }