tokenizer: Make consume_name faster. - #449
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Skip over runs of ascii and such in a tight loop. This is one of the hottest functions and match_byte! adds extra branches for the common cases.
emilio
enabled auto-merge
August 28, 2026 19:08
nicoburns
approved these changes
Aug 28, 2026
nicoburns
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nicoburns
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This looks correct to me
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| // These are the overwhelmingly common bytes, that we can just skip over in a tight loop. | ||
| static IS_SIMPLE_NAME_BYTE: [bool; 256] = { | ||
| let mut table = [false; 256]; | ||
| let mut i = 0; | ||
| while i < 256 { | ||
| table[i as usize] = matches!(i as u8, b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' | b'_' | b'-' | b'\xC0'..=b'\xEF'); | ||
| i += 1; | ||
| } | ||
| table | ||
| }; |
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Given that this is a table of bool you could also try a bitset, and see if that's any faster.
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A bitset was quite a few more instructions: https://rust.godbolt.org/z/G94TTEo7G
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| // start_pos is the end of the previous token, therefore at a code point boundary | ||
| let start_pos = tokenizer.position(); | ||
| let mut value_bytes; |
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Nit: an explicit type annotation on value_bytes would nice.
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Gah I guess the auto-merge got faster. It's not a huge deal tho and it's pre-existing...
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Skip over runs of ascii and such in a tight loop. This is one of the hottest functions and match_byte! adds extra branches for the common cases.