Optimizing closures in O(0) time
Optimizing closures in O(0) time
复制标题
在 O(0) 时间内优化闭包
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. Dybvig
中科院分区：
文献类型：
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作者：
Andrew W. Keep;Alex Hearn;R. Dybvig
用于表示一级过程的平闭包模型简单、空间安全且高效，允许使用单个内存间接访问自由变量的值或位置。它是一个程序员可以理解的简单模型，允许程序员预测程序的最坏情况。本文提出了一组优化，改进了平面闭包模型沿着的算法，实现它们，它表明，优化一起消除了超过50%的运行时闭包创建和自由变量访问的开销在实践中，与微不足道的编译时开销。这些优化不会增加开销并保持空间安全，从而保留了flat-closure模型的优点。
The flat-closure model for the representation of first-class procedures is simple, safe-for-space, and efficient, allowing the values or locations of free variables to be accessed with a single memory indirect. It is a straightforward model for programmers to understand, allowing programmers to predict the worst-case behavior of their programs. This paper presents a set of optimizations that improve upon the flat-closure model along with an algorithm that implements them, and it shows that the optimizations together eliminate over 50% of run-time closure-creation and free-variable access overhead in practice, with insignificant compile-time overhead. The optimizations never add overhead and remain safe-for-space, thus preserving the benefits of the flat-closure model.