Flow类中的resolveBreaks与resolveContinues

最新推荐文章于 2024-08-03 15:20:58 发布

转载最新推荐文章于 2024-08-03 15:20:58 发布 · 179 阅读

0 ·

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/extjs4/p/9377430.html

本文深入探讨了Java编译器内部如何处理continue和break语句，通过具体的代码片段展示了如何解析并处理这些控制流语句，为理解Java编译原理提供了宝贵的见解。

 /** Resolve all continues of this statement. */
boolean resolveContinues(JCTree tree) {
    boolean result = false;
    List<PendingExit> exits = pendingExits.toList();
    pendingExits = new ListBuffer<PendingExit>();

    for (; exits.nonEmpty(); exits = exits.tail) {
        PendingExit exit = exits.head;
        if (exit.tree.getTag() == JCTree.CONTINUE &&
                 ((JCContinue) exit.tree).target == tree) {

            inits.andSet(exit.inits); // 相当于取交集
            uninits.andSet(exit.uninits);
            result = true;
        } else {
            pendingExits.append(exit);
        }
    }
    return result;
}

调用的地方如下截图：

/** Resolve all breaks of this statement. */
boolean resolveBreaks(JCTree tree, // tree是break的跳出目标
                      ListBuffer<PendingExit> oldPendingExits) {
    boolean result = false;
    List<PendingExit> exits = pendingExits.toList();
    pendingExits = oldPendingExits;
    for (; exits.nonEmpty(); exits = exits.tail) {
        PendingExit exit = exits.head;
        if (exit.tree.getTag() == JCTree.BREAK &&
                    ((JCBreak) exit.tree).target == tree) {
            inits.andSet(exit.inits);
            uninits.andSet(exit.uninits);
            result = true;
        } else {
            pendingExits.append(exit);
        }
    }
    return result;
}

调用的地方如下：　　