perf(parser): fast path identifier parsing and inline operator helpers#22650
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#22650) ## Summary Two small but compounding hot-path wins in the parser: - **`parse_identifier_kind` fast path** — for unescaped identifiers (the common case), slice directly from source text via `token_source` instead of going through `lexer.get_string()`, which dispatches on `Kind`. This is the same approach as Cam's earlier branch (`03-31-perf_parser_fast_path_in_parse_identifier_kind...`) that never landed. - **`#[inline]` on operator helpers** — `kind_to_precedence`, `map_binary_operator`, `map_logical_operator`, `map_unary_operator`, `map_update_operator`, `map_assignment_operator`. They're called from the Pratt loop in `parse_binary_expression_rest` but lived in a sibling module where rustc wouldn't auto-inline them. ## Benchmarks Criterion medians (baseline → patched, lower is better): | File | Baseline | Patched | Δ | | --- | --- | --- | --- | | `parser/binder.ts` | 433.60 µs | 425.28 µs | **~1.9%** | | `parser/kitchen-sink.tsx` | 3.5702 ms | 3.5368 ms | ~0.9% | | `parser/cal.com.tsx` | 3.9827 ms | 3.9519 ms | ~0.8% | | `estree_tokens/checker.ts` | 9.6080 ms | 9.5566 ms | ~0.5% | | `estree/checker.ts` | 13.395 ms | 13.373 ms | ~0.2% | Identifier-dense TypeScript benefits the most, as expected — `binder.ts` is mostly identifiers. ## Notes - No allocation regression (`cargo allocs` snapshot unchanged). - `cargo coverage -- parser` still 100% on test262 (47115/47115 positive, 4588/4588 negative). - `cargo test -p oxc_parser`, `cargo clippy`, `just fmt` all clean. 🤖 Generated with [Claude Code](https://claude.com/claude-code)
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### 🚀 Features - e857b0c napi/minify: Expose legalComments option and result (#20370) (Boshen) - 661132d parser: More friendly error messages for rest assignment target and rest binding element (#22719) (sapphi-red) - ee659b6 transformer/legacy-decorator: Add `strictNullChecks` option for nullable-union design:type (#22266) (Kyle Cannon) ### 🐛 Bug Fixes - e1d064e transformer/class-properties: Reparent lifted private method helpers (#22716) (Cameron) - 4ac0fca minifier: Preserve `0 && (module.exports = { ... })` cjs-module-lexer hint (#22729) (Dunqing) - 40ff611 minifier: Mark peephole loop changed when dropping dead-after-throw statement (#22722) (Dunqing) - 2f7b210 codegen: Emit pife-arrow/function leading comments inside the wrap (#22720) (Dunqing) - e184f74 parser: Improve invalid `import` property access diagnostic (#22693) (camc314) - 7baed9c transformer/private-method: Clear inherited strict flags (#22508) (camc314) - a9ad27e parser: Keep annotation comments leading without preceding newline (#22711) (Dunqing) - 9ea4d64 minifier: Re-evaluate pure/no-side-effects flags after peephole inlining (#22595) (Dunqing) - 07afbb6 minifier: Drop empty-body IIFE wrapper when called with arguments (#22589) (Dunqing) - fa7c463 semantic: Correct TS enum member symbol spans (#22689) (camc314) - 26b9396 semantic: Resolve parameter decorators outside parameter scope (#22623) (camc314) - b284045 parser: Switch to module goal eagerly on `export` (#22684) (Boshen) - dfa931d semantic: Propagate unresolved auto-increment enum value instead of defaulting to 0 (#22646) (Dunqing) - 69a6ba6 transformer/legacy-decorator: Emit Array for ReadonlyArray<T> in decorator metadata (#22265) (Kyle Cannon) - e421ef0 transformer/legacy-decorator: Return runtime binding for design:type (#22640) (Dunqing) - d61e1d7 codegen: Preserve verbatim text of pure/no-side-effects comments (#22525) (Dunqing) - 702b14e minifier: Preserve IIFE structure in DCE-only mode (#22547) (Dunqing) - 917da24 parser: Apply PURE comment through member-access chains (#22566) (Dunqing) - a069b1c codegen: Preserve quotes for cjs-module-lexer equality strings (#22551) (Dunqing) ### ⚡ Performance - 2f623b0 semantic: Skip unresolved checks for re-exports (#22660) (camc314) - 0d9553d semantic: Early-exit `check_object_expression` for objects with <2 properties (#22668) (Dunqing) - d721ad9 semantic: Use direct grandparent lookup for TS type parameters (#22658) (camc314) - 0aff288 semantic: Reorder numeric literal strict mode checks (#22657) (camc314) - 4d5ddb1 semantic: Reorder binding identifier checks (#22656) (camc314) - e32acd8 semantic: Reorder identifier ambient binding check (#22653) (camc314) - 09fe178 semantic: Reorder ident reference strict mode check (#22652) (camc314) - 4b6add2 semantic: Avoid duplicate ident clone for bindings (#22663) (camc314) - 82f9662 parser: Check identifier kind before context flag (#22662) (camc314) - d7cd951 parser: Fast path identifier parsing and inline operator helpers (#22650) (Boshen) - 7b84314 semantic: Use direct byte access for numeric leading-zero check (#22642) (camc314) - 0345a31 semantic: Pre-size class elements hash map (#22618) (camc314) - 04d3065 minifier: Drop per-call buffers in try_fold_concat (#22596) (Dunqing) - 4f289f1 semantic: Resolve_references_for_current_scope without a temp Vec (#22599) (Dunqing) - e862c15 semantic: Avoid heap alloc for var hoist scope ids (#22603) (Dunqing) - 8ff8674 semantic: Early return if `excess` is `0` in `Stats::increase_by` (#22616) (camc314) - 7a4120e semantic: Pre-reserve unresolved_references using Stats::references (#22580) (Dunqing) Co-authored-by: Dunqing <29533304+Dunqing@users.noreply.github.com>
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Summary
Two small but compounding hot-path wins in the parser:
parse_identifier_kindfast path — for unescaped identifiers (the common case), slice directly from source text viatoken_sourceinstead of going throughlexer.get_string(), which dispatches onKind. This is the same approach as Cam's earlier branch (03-31-perf_parser_fast_path_in_parse_identifier_kind...) that never landed.#[inline]on operator helpers —kind_to_precedence,map_binary_operator,map_logical_operator,map_unary_operator,map_update_operator,map_assignment_operator. They're called from the Pratt loop inparse_binary_expression_restbut lived in a sibling module where rustc wouldn't auto-inline them.Benchmarks
Criterion medians (baseline → patched, lower is better):
parser/binder.tsparser/kitchen-sink.tsxparser/cal.com.tsxestree_tokens/checker.tsestree/checker.tsIdentifier-dense TypeScript benefits the most, as expected —
binder.tsis mostly identifiers.Notes
cargo allocssnapshot unchanged).cargo coverage -- parserstill 100% on test262 (47115/47115 positive, 4588/4588 negative).cargo test -p oxc_parser,cargo clippy,just fmtall clean.🤖 Generated with Claude Code