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perf(parser): table-driven operator precedence lookup (#23346)

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`kind_to_precedence` is called for every token while parsing binary expressions; replace the branchy `match` with a 256-entry lookup table indexed by `Kind` discriminant.

Interleaved A/B benchmark (12 alternating runs, medians) showed ~-1.3% on binder.ts from this change alone. Conformance and snapshots unchanged.

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This commit is contained in:
Boshen committed 2026-06-12 14:32:08 +00:00
1 parent 2120ecfb45
commit 2783295639
1 file changed
+33 -18
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crates/oxc_parser/src/js/operator.rs
+33 -18
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@@ -7,26 +7,41 @@ use oxc_syntax::{
use crate::lexer::Kind;
static PRECEDENCE_TABLE: [Option<Precedence>; 256] = {
let mut table = [None; 256];
table[Kind::Question2 as usize] = Some(Precedence::NullishCoalescing);
table[Kind::Pipe2 as usize] = Some(Precedence::LogicalOr);
table[Kind::Amp2 as usize] = Some(Precedence::LogicalAnd);
table[Kind::Pipe as usize] = Some(Precedence::BitwiseOr);
table[Kind::Caret as usize] = Some(Precedence::BitwiseXor);
table[Kind::Amp as usize] = Some(Precedence::BitwiseAnd);
table[Kind::Eq2 as usize] = Some(Precedence::Equals);
table[Kind::Eq3 as usize] = Some(Precedence::Equals);
table[Kind::Neq as usize] = Some(Precedence::Equals);
table[Kind::Neq2 as usize] = Some(Precedence::Equals);
table[Kind::LAngle as usize] = Some(Precedence::Compare);
table[Kind::RAngle as usize] = Some(Precedence::Compare);
table[Kind::LtEq as usize] = Some(Precedence::Compare);
table[Kind::GtEq as usize] = Some(Precedence::Compare);
table[Kind::Instanceof as usize] = Some(Precedence::Compare);
table[Kind::In as usize] = Some(Precedence::Compare);
table[Kind::ShiftLeft as usize] = Some(Precedence::Shift);
table[Kind::ShiftRight as usize] = Some(Precedence::Shift);
table[Kind::ShiftRight3 as usize] = Some(Precedence::Shift);
table[Kind::Plus as usize] = Some(Precedence::Add);
table[Kind::Minus as usize] = Some(Precedence::Add);
table[Kind::Star as usize] = Some(Precedence::Multiply);
table[Kind::Slash as usize] = Some(Precedence::Multiply);
table[Kind::Percent as usize] = Some(Precedence::Multiply);
table[Kind::Star2 as usize] = Some(Precedence::Exponentiation);
table[Kind::As as usize] = Some(Precedence::Compare);
table[Kind::Satisfies as usize] = Some(Precedence::Compare);
table
};
#[inline]
pub fn kind_to_precedence(kind: Kind) -> Option<Precedence> {
match kind {
Kind::Question2 => Some(Precedence::NullishCoalescing),
Kind::Pipe2 => Some(Precedence::LogicalOr),
Kind::Amp2 => Some(Precedence::LogicalAnd),
Kind::Pipe => Some(Precedence::BitwiseOr),
Kind::Caret => Some(Precedence::BitwiseXor),
Kind::Amp => Some(Precedence::BitwiseAnd),
Kind::Eq2 | Kind::Eq3 | Kind::Neq | Kind::Neq2 => Some(Precedence::Equals),
Kind::LAngle | Kind::RAngle | Kind::LtEq | Kind::GtEq | Kind::Instanceof | Kind::In => {
Some(Precedence::Compare)
}
Kind::ShiftLeft | Kind::ShiftRight | Kind::ShiftRight3 => Some(Precedence::Shift),
Kind::Plus | Kind::Minus => Some(Precedence::Add),
Kind::Star | Kind::Slash | Kind::Percent => Some(Precedence::Multiply),
Kind::Star2 => Some(Precedence::Exponentiation),
Kind::As | Kind::Satisfies => Some(Precedence::Compare),
_ => None,
}
PRECEDENCE_TABLE[kind as usize]
}
#[inline]