• CanadaPlus
    1·
    21 hours ago

    I mean, “criticism” is a little extreme even, because it’s a humour post, and I was just riffing back.

    Apparently GCC does indeed do tail-call optimization at -O2

    Hmm, I wonder why it’s considered O2 heavy. The concept of turning tail recursion into loops is simple.

    But in that case, I’m not sure why the solution to the denial of service vulnerability isn’t just “compile with -foptimize-sibling-calls.”

    Probably because some of the recursion involved is non-tail. Actually, it looks like GCC might still be able to cases of corecursion where the functions are “stack compatibale”, but presumably most functions aren’t, and who knows what little knots they tied the parsing functions in this XML library into.

      • CanadaPlus
        1·
        2 hours ago

        Yes, definitely. Rereading the StackOverflow, “stack compatible” just means it can mutate the stack frame in place without resizing it in the optimised code. There’s a number of ways trying to handle tail (co)recursion sucks if you try and get around that. Here’s a Dr. Dobbs about it.