Currently, the behavior of IntegerIndexedElementSet is to return false if the index being set is outside the array bounds. This return-false directly feeds into the result of [[Set]] on a typed array. The result is that in strict mode code, setting an out-of-bounds array element throws a TypeError.
I've heard claims from other SpiderMonkey implementers that this requirement makes it difficult to implement high-performance JIT optimizations for code that assigns into typed arrays, except in the case that the array length is observable in context, the typed array never escapes anywhere, its backing ArrayBuffer never escapes anywhere, etc. Restrictions that generally aren't very easy to determine with local information observable by a JIT. And while quite often such high-performance code isn't strict mode code, it's doubtful that will be true far into the future. >From that point of view, it would be better if IntegerIndexedElementSet just >returned true in this case -- indicate success without doing anything. What >are the compelling reasons to not do this? Jeff _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
