86 lines
3.1 KiB
Java
86 lines
3.1 KiB
Java
/*
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* Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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import java.lang.foreign.*;
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import java.lang.invoke.MethodHandle;
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import java.lang.invoke.MethodHandles;
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import java.lang.invoke.MethodType;
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import java.util.concurrent.CountDownLatch;
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/**
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* Test native threads attaching implicitly to the VM by means of an upcall.
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*/
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public class ImplicitAttach {
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private static final ValueLayout.OfInt C_INT = ValueLayout.JAVA_INT;
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private static final AddressLayout C_POINTER = ValueLayout.ADDRESS;
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private static volatile CountDownLatch latch;
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public static void main(String[] args) throws Throwable {
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int threadCount;
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if (args.length > 0) {
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threadCount = Integer.parseInt(args[0]);
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} else {
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threadCount = 2;
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}
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latch = new CountDownLatch(threadCount);
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Linker abi;
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try {
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abi = Linker.nativeLinker();
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} catch (UnsupportedOperationException e) {
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System.out.println("Test skipped, no native linker on this platform");
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return;
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}
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// stub to invoke callback
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MethodHandle callback = MethodHandles.lookup()
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.findStatic(ImplicitAttach.class, "callback", MethodType.methodType(void.class));
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MemorySegment upcallStub = abi.upcallStub(callback,
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FunctionDescriptor.ofVoid(),
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Arena.global());
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// void start_threads(int count, void *(*f)(void *))
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SymbolLookup symbolLookup = SymbolLookup.loaderLookup();
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MemorySegment symbol = symbolLookup.find("start_threads").orElseThrow();
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FunctionDescriptor desc = FunctionDescriptor.ofVoid(C_INT, C_POINTER);
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MethodHandle start_threads = abi.downcallHandle(symbol, desc);
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// start the threads and wait for the threads to call home
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start_threads.invoke(threadCount, upcallStub);
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latch.await();
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}
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/**
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* Invoked from native thread.
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*/
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private static void callback() {
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System.out.println(Thread.currentThread());
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latch.countDown();
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}
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static {
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System.loadLibrary("ImplicitAttach");
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}
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}
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