Symbol takes half a second to demangle with default configuration

[athre0z]

Symbol takes half a second to demangle with default configuration

[khuey]

I released 0.4.2 with this fixed.

[khuey]

This pathological symbol triggers the default recursion limits in cpp_demangle. The error handling paths are slow (I haven't investigated that) and lead to the 0.5 second runtime you see. If you bump the recursion limits (I haven't attempted to find minimal values here) like so, it will parse correctly in less than a tenth of that time.

if let Ok(sym) = cpp_demangle::BorrowedSymbol::new_with_options(name.as_bytes(),  &ParseOptions::default().recursion_limit(256)) {
    let mut demangled = String::new();
    let options = cpp_demangle::DemangleOptions::default()
        .recursion_limit(256);
    if let Ok(()) = sym.structured_demangle(&mut demangled, &options) {
        dbg!(demangled);
    }
}

[athre0z]

Thanks for the swift response!

Oh wow, yeah, I can confirm that this speeds things up quite significantly. The error path being slow certainly wasn't on my list of possible reasons here -- I figured it would just bubble up an error and that's it. Interesting.

I actually have to raise the limit to 512 in order to not run into this for all symbols in this executable (also not minimized, but 256 is not enough so I just doubled).

[athre0z]

Thanks a lot for the swift fix -- works great here! The pathological executable where it used to take more than an hour to demangle all the symbols now parses in 3 seconds.

[khuey]

Was that with the recursion limit at the default?

[athre0z]

Yes.

[khuey]

Great!