Static regexes are very slow to create #13842
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I-compiletime
Issue: Problems and improvements with respect to compile times.
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huonw
changed the title
huonw
changed the title
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cc @BurntSushi |
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This looks like it isn't just the expansion, but also the extra code that is being created. e.g. compiling
It looks like this may just be essentially a function of the amount of code being generated, with not much scope for fixing other than "make rustc faster". |
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This issue has been moved to the regex repo: rust-lang/regex#27 |
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I'm re-opening this after it was moved to rust-lang/regex because I think it is predominantly related to compile times of lots of code. With that said, I'm also leaving this issue open in rust-lang/regex because the macro should probably generate a lot less code than it does today. |
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Updated. Code: #![feature(plugin)]
#![allow(dead_code)]
#![plugin(regex_macros)]
extern crate regex;
#[cfg(short)]
fn short() {
regex!("a");
}
#[cfg(medium)]
fn medium() {
// 500
regex!("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
}
#[cfg(long)]
fn long() {
// 1000
regex!("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
}
fn main() {}Output: with time-passes: I agree with @huonw 's assessment:
In addition, As such, I'm gonna give this a close: in general, we should get faster, but this specific situation is pretty obscure and not particularly degenerate. |
flip1995
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to flip1995/rust
that referenced
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Dec 26, 2024
Close rust-lang#13842 changelog: [`indexing_slicing`]: add allow-indexing-slicing-in-tests option to be able ignore at test
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They don't take nearly this long to just compile as dynamic ones, so I would guess it's the extra work that the generating macro is doing. (Note the
--no-transthere, so it isn't just the extra code making LLVM slow.)A perf trace identifies
rustc librustc-4283bb68-0.11-pre.so [.] hashmap::HashMap$LT$K$C$$x20V$C$$x20H$GT$::search::h14555543045583792107::v0.11.preas taking a lot (10.18%) of time.The text was updated successfully, but these errors were encountered: