All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • com.oracle.truffle.api.vm.ContextThreadLocal Maven / Gradle / Ivy

    Go to download

    Truffle is a multi-language framework for executing dynamic languages that achieves high performance when combined with Graal.

    There is a newer version: 1.0.0-rc7
    Show newest version
    /*
 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.truffle.api.vm;

import com.oracle.truffle.api.Assumption;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.Truffle;
import com.oracle.truffle.api.TruffleOptions;

final class ContextThreadLocal extends ThreadLocal {

    private final Assumption singleThread = Truffle.getRuntime().createAssumption("constant context store");
    private PolyglotContextImpl firstContext;
    @CompilationFinal private volatile Thread firstThread;

    @Override
    protected Object initialValue() {
        if (Thread.currentThread() == firstThread) {
            // must only happen once
            Object context = firstContext;
            firstContext = null;
            firstThread = null;
            return context;
        }
        return null;
    }

    public boolean isSet() {
        if (singleThread.isValid()) {
            boolean set = firstContext != null;
            return (TruffleOptions.AOT ? currentThread() : Thread.currentThread()) == firstThread && set;
        } else {
            return getTL() != null;
        }
    }

    @Override
    public Object get() {
        Object context;
        if (singleThread.isValid()) {
            if ((TruffleOptions.AOT ? currentThread() : Thread.currentThread()) == firstThread) {
                context = firstContext;
            } else {
                CompilerDirectives.transferToInterpreter();
                context = getImplSlowPath();
            }
        } else {
            context = getTL();
        }
        return context;
    }

    @TruffleBoundary
    static Thread currentThread() {
        return Thread.currentThread();
    }

    @Override
    public void set(Object value) {
        setReturnParent(value);
    }

    Object setReturnParent(Object value) {
        if (singleThread.isValid()) {
            Object prev;
            if ((TruffleOptions.AOT ? currentThread() : Thread.currentThread()) == firstThread) {
                prev = this.firstContext;
                this.firstContext = (PolyglotContextImpl) value;
            } else {
                CompilerDirectives.transferToInterpreter();
                prev = setReturnParentSlowPath(value);
            }
            return prev;
        } else {
            return setTLReturnParent(value);
        }
    }

    private synchronized Object getImplSlowPath() {
        if (!singleThread.isValid()) {
            return getTL();
        }
        return null;
    }

    @TruffleBoundary
    private Object getTL() {
        Thread current = Thread.currentThread();
        if (current instanceof PolyglotThread) {
            PolyglotThread polyglotThread = ((PolyglotThread) current);
            Object context = polyglotThread.context;
            if (context == null && firstThread == current) {
                context = polyglotThread.context = firstContext;
                firstContext = null;
                firstThread = null;
            }
            return context;
        } else {
            return super.get();
        }
    }

    @TruffleBoundary
    private Object setTLReturnParent(Object context) {
        Thread current = Thread.currentThread();
        if (current instanceof PolyglotThread) {
            PolyglotThread polyglotThread = ((PolyglotThread) current);
            Object prev = polyglotThread.context;
            polyglotThread.context = context;
            return prev;
        } else {
            Object prev = super.get();
            super.set(context);
            return prev;
        }
    }

    private synchronized Object setReturnParentSlowPath(Object context) {
        if (!singleThread.isValid()) {
            return setTLReturnParent(context);
        }
        Thread currentThread = Thread.currentThread();
        Thread storeThread = firstThread;
        Object prev = this.firstContext;
        if (currentThread == storeThread) {
            this.firstContext = (PolyglotContextImpl) context;
        } else {
            if (storeThread == null) {
                this.firstThread = currentThread;
                this.firstContext = (PolyglotContextImpl) context;
            } else {
                singleThread.invalidate();
                return setTLReturnParent(context);
            }
        }
        return prev;
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException();
    }

}
    
    
    
    

    




    
    
    © 2015 - 2025 Weber Informatics LLC | Privacy Policy