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Only assert the Parser size on specific arches #135855

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Jan 24, 2025
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Only assert the Parser size on specific arches #135855

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5 changes: 3 additions & 2 deletions compiler/rustc_parse/src/parser/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -189,8 +189,9 @@ pub struct Parser<'a> {
}

// This type is used a lot, e.g. it's cloned when matching many declarative macro rules with
// nonterminals. Make sure it doesn't unintentionally get bigger.
#[cfg(all(target_pointer_width = "64", not(target_arch = "s390x")))]
// nonterminals. Make sure it doesn't unintentionally get bigger. We only check a few arches
// though, because `TokenTypeSet(u128)` alignment varies on others, changing the total size.
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Not this PR, and I don't know if it's worth bothering, but could try changing the other type to a https://doc.rust-lang.org/nightly/nightly-rustc/rustc_data_structures/packed/struct.Pu128.html so it'd be smaller on x64 too.

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Either that, or put #[repr(packed(8))] directly on TokenTypeSet too. I have no idea if there are enough of these being passed around to really matter though.

#[cfg(all(target_pointer_width = "64", any(target_arch = "aarch64", target_arch = "x86_64")))]
rustc_data_structures::static_assert_size!(Parser<'_>, 288);

/// Stores span information about a closure.
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