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Shrink ParserState - #457
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A less ugly alternative for the last commit might be to just reduce the line count to a |
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emilio
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| /// Current line number shifted by `Self::BLOCK_TYPE_BITS`, with the low 2 bits holding the | ||
| /// `BlockType` discriminant of the block the last returned token opened (if any). | ||
| line_number_and_block_type: u32, | ||
| } |
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Further microbenchmarking showed that most of the win (on those microbenchmarks at least) comes from making the Clone impl a memcpy rather than a per-field copy (why does rustc not collapse everything onto a memcpy without derive(Copy), I don't know)...
Making it smaller is a smaller win on top, so maybe we should just take this anyway, since I think it's not too complicated...
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…ystem-reviewers,supply-chain-reviewers,dshin This needs a tweak in servo/ for a behavior change on how arbitrary substitution functions are dealt with, see the discussion in servo/rust-cssparser#456. I wanted to do this once servo/rust-cssparser#457 was reviewed but that's taking a while and I need to work on other bugfixes too, so landing the update to main first. Differential Revision: https://phabricator.services.mozilla.com/D331712
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…ystem-reviewers,supply-chain-reviewers,dshin This needs a tweak in servo/ for a behavior change on how arbitrary substitution functions are dealt with, see the discussion in servo/rust-cssparser#456. I wanted to do this once servo/rust-cssparser#457 was reviewed but that's taking a while and I need to work on other bugfixes too, so landing the update to main first. Differential Revision: https://phabricator.services.mozilla.com/D331712
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Definitely in the territory of "should only do this in a hot loop". But it sounds like that's the case here.
We already truncate column numbers to u32, so this gives the same answer it would otherwise give, and saves some storage (not in this patch because ParserState is still 24 bytes, but we can improve on that in a bit).
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…k type. The line number range gets a bit smaller, but it pays off by making state restoration faster, which is a lot hotter.
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See the two commits. This improves state restoration performance which is pretty hot.