/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.lang.reflect.InvocationHandler;
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import java.lang.reflect.Method;
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import java.lang.reflect.Proxy;
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import java.util.ArrayList;
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class OOMEHelper {
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int nullField;
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}
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/**
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* Test that null field access under an OOME situation works.
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*
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* The test relies on compile-time verification. This class is compile-time verifiable, so when
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* loaded at runtime will not transitively load referenced types eagerly. In that case, our code
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* to give descriptive NullPointerExceptions for the field access to the null "instance" of
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* OOMEHelper in nullAccess() will be the first attempting to load the class, and, under the
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* induced low-memory situation, will throw itself an OutOfMemoryError.
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*/
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public class OOMEOnNullAccess {
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static ArrayList<Object> storage = new ArrayList<>(100000);
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public static void main(String[] args) {
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// Stop the JIT to be sure nothing is running that could be resolving classes or causing
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// verification.
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Main.stopJit();
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Main.waitForCompilation();
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int l = 1024 * 1024;
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while (l > 8) {
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try {
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storage.add(new byte[l]);
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} catch (OutOfMemoryError e) {
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l = l/2;
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}
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}
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try {
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nullAccess(null);
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storage.clear();
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throw new RuntimeException("Did not receive exception!");
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} catch (OutOfMemoryError oome) {
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storage.clear();
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System.err.println("Received OOME");
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} finally {
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// Even if it's an unexpected error, clear so that we can print things later.
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storage.clear();
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}
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Main.startJit();
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}
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public static int nullAccess(OOMEHelper nullInstance) {
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// Under AOT, this access is the first one to actually load the OOMEHelper class, so
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// we can pretty print the name and such.
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return nullInstance.nullField;
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}
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}
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