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perf(syntax): pack ASCII identifier tables into single bitflag table#19088

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perf/pack-ascii-id-flags
Feb 7, 2026
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perf(syntax): pack ASCII identifier tables into single bitflag table#19088
graphite-app[bot] merged 1 commit intomainfrom
perf/pack-ascii-id-flags

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@Boshen Boshen commented Feb 7, 2026

Summary

  • Replace two [bool; 128] tables (ASCII_START, ASCII_CONTINUE — 256 bytes, 4 cache lines) with one [u8; 128] bitflag table (ASCII_ID_FLAGS — 128 bytes, 2 cache lines)
  • Each byte packs ID_START (bit 0) and ID_CONTINUE (bit 1), so both is_identifier_start_ascii and is_identifier_part_ascii hit the same cache line for any given character
  • Remove unsafe { assert_unchecked! } calls in the bulk is_identifier_name by indexing the flags table directly with byte values

🤖 Generated with Claude Code

Copilot AI review requested due to automatic review settings February 7, 2026 01:14
@github-actions github-actions bot added the C-performance Category - Solution not expected to change functional behavior, only performance label Feb 7, 2026
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Pull request overview

This PR optimizes ASCII identifier classification in oxc_syntax by packing identifier start/continue information into a single cache-friendly bitflag table and simplifying the ASCII fast path in is_identifier_name.

Changes:

  • Replaced ASCII_START / ASCII_CONTINUE boolean tables with a single ASCII_ID_FLAGS bitflag table.
  • Updated ASCII identifier checks to use ID_START / ID_CONTINUE bitmasks.
  • Removed assert_unchecked! usage in the ASCII bulk scan within is_identifier_name.

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codspeed-hq bot commented Feb 7, 2026

CodSpeed Performance Report

Merging this PR will not alter performance

Comparing perf/pack-ascii-id-flags (2dc3dc3) with main (65c6c33)

Summary

✅ 47 untouched benchmarks
⏩ 3 skipped benchmarks1

Footnotes

  1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

@Boshen Boshen added the 0-merge Merge with Graphite Merge Queue label Feb 7, 2026
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Boshen commented Feb 7, 2026 •
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@Boshen
perf(syntax): pack ASCII identifier tables into single bitflag table (#…
9eb16b3 
…19088)

## Summary

- Replace two `[bool; 128]` tables (`ASCII_START`, `ASCII_CONTINUE` — 256 bytes, 4 cache lines) with one `[u8; 128]` bitflag table (`ASCII_ID_FLAGS` — 128 bytes, 2 cache lines)
- Each byte packs `ID_START` (bit 0) and `ID_CONTINUE` (bit 1), so both `is_identifier_start_ascii` and `is_identifier_part_ascii` hit the same cache line for any given character
- Remove `unsafe { assert_unchecked! }` calls in the bulk `is_identifier_name` by indexing the flags table directly with byte values

🤖 Generated with [Claude Code](https://claude.com/claude-code)
@graphite-app graphite-app bot force-pushed the perf/pack-ascii-id-flags branch from 2dc3dc3 to 9eb16b3 Compare February 7, 2026 01:28
@graphite-app graphite-app bot merged commit 9eb16b3 into main Feb 7, 2026
22 checks passed
@graphite-app graphite-app bot deleted the perf/pack-ascii-id-flags branch February 7, 2026 01:35
@graphite-app graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Feb 7, 2026
This was referenced Feb 9, 2026
Closed
Merged
camc314 added a commit that referenced this pull request Feb 10, 2026
@Boshen @camc314
release(crates): oxc v0.113.0 (#19210)
acdb40e 
### 💥 BREAKING CHANGES

- 2bf7293 mangler: [**BREAKING**] Enable `top_level` by default for
modules and commonjs (#18278) (sapphi-red)
- 48b0542 span: [**BREAKING**] SourceType::ts should set module to
unambigious (#18873) (Boshen)

### 🚀 Features

- 500d071 minifier: Local traverse ctx and generated minifier traverse
(#19106) (Boshen)
- 142a1be parser: Detect binary files with TS1490 error (#19047)
(Boshen)
- e316857 allocator/bitset: Add `Ones` iterator to `BitSet` (#19027)
(sapphi-red)
- 742ad3f minifier: Default `invalid_import_side_effects` to `false`
(#18916) (sapphi-red)
- 0eff6be parser: Error JSX-like type assertions and generics in
`.mts`/`.cts` (#18910) (Boshen)
- 18320c6 span: Store file extension in `SourceType` (#18893) (Boshen)

### 🐛 Bug Fixes

- a7514e4 isolated-declarations: Preserve const context in literal type
inference (#19178) (camc314)
- 312e756 isolated-declarations: Preserve readonly literal initializers
(#19177) (camc314)
- d0ca8d0 isolated-declarations: Skip parenthesis when inferring type
(#19176) (camc314)
- 110c300 oxc_ecmascript: `+[false]` and `+[true]` should evaluate to
`NaN` (#19174) (copilot-swe-agent)
- f32ea19 semantic: Report redeclaration error for import bindings
conflicting with value declarations (#19068) (Boshen)
- 3aeba7a semantic: Report redeclaration error for `function a() {} var
a` in module mode (#19041) (Boshen)
- 35e32c6 coverage: Match Babel's options.json inheritance for test
fixtures (#19002) (Boshen)
- 463d60d semantic: Skip TS2391 for standalone computed-name class
methods (#19025) (Boshen)
- 56c086b parser: Add modifier ordering validation (TS1029) (#19024)
(Boshen)
- 6067a49 linter/jsdoc: False positive in `check-tag-names` for `@` in
email addresses and npm scopes (#19021) (Boshen)
- b13bb70 semantic/jsdoc: Inline tags like `{@link}` break jsdoc parsing
(#19019) (Boshen)
- e3609e3 regular_expression: Preserve UnicodeEscape CharacterKind in
string literals (#18998) (Boshen)
- 57917ee parser: Parse decorators on rest parameters (#18938) (Boshen)
- 487601b napi: Disable mimalloc on Windows to fix worker_threads crash
(#18923) (Boshen)
- 1f6b193 parser: Validate TypeScript import type options (#18889)
(Boshen)
- 1663184 parser: Allow conditional types in function type parameters
(#18886) (Boshen)
- 5758046 parser: Error on property access after instantiation
expression (#18887) (Boshen)
- 5eb4a94 parser: Handle `<<` as two `<` tokens in type argument
contexts (#18885) (Boshen)

### ⚡ Performance

- ed8c054 oxc_str: Add precomputed hash to Ident for fast HashMap
lookups (#19143) (Boshen)
- d4a0867 transformer_plugins: Switch ReplaceGlobalDefines from Traverse
to VisitMut (#19146) (Boshen)
- 9eb16b3 syntax: Pack ASCII identifier tables into single bitflag table
(#19088) (Boshen)
- e7595d1 mangler: Use BitSet for exported symbols set (#19023)
(sapphi-red)
- 2537924 semantic: Optimize scope resolution with fast paths and
inlining (#19029) (Boshen)
- 69a8d85 mangler: Use BitSet for keep_names symbols set (#19028)
(sapphi-red)
- f78c525 parser: Try hybrid parsing for jsx children and closing
element/fragments (#18789) (camchenry)

Co-authored-by: camc314 <[email protected]>
@Boshen Boshen mentioned this pull request Feb 10, 2026
Closed
owjs3901 pushed a commit to owjs3901/oxc that referenced this pull request Feb 11, 2026
@Boshen @camc314 @owjs3901
release(crates): oxc v0.113.0 (oxc-project#19210)
68e76fb 
### 💥 BREAKING CHANGES

- 2bf7293 mangler: [**BREAKING**] Enable `top_level` by default for
modules and commonjs (oxc-project#18278) (sapphi-red)
- 48b0542 span: [**BREAKING**] SourceType::ts should set module to
unambigious (oxc-project#18873) (Boshen)

### 🚀 Features

- 500d071 minifier: Local traverse ctx and generated minifier traverse
(oxc-project#19106) (Boshen)
- 142a1be parser: Detect binary files with TS1490 error (oxc-project#19047)
(Boshen)
- e316857 allocator/bitset: Add `Ones` iterator to `BitSet` (oxc-project#19027)
(sapphi-red)
- 742ad3f minifier: Default `invalid_import_side_effects` to `false`
(oxc-project#18916) (sapphi-red)
- 0eff6be parser: Error JSX-like type assertions and generics in
`.mts`/`.cts` (oxc-project#18910) (Boshen)
- 18320c6 span: Store file extension in `SourceType` (oxc-project#18893) (Boshen)

### 🐛 Bug Fixes

- a7514e4 isolated-declarations: Preserve const context in literal type
inference (oxc-project#19178) (camc314)
- 312e756 isolated-declarations: Preserve readonly literal initializers
(oxc-project#19177) (camc314)
- d0ca8d0 isolated-declarations: Skip parenthesis when inferring type
(oxc-project#19176) (camc314)
- 110c300 oxc_ecmascript: `+[false]` and `+[true]` should evaluate to
`NaN` (oxc-project#19174) (copilot-swe-agent)
- f32ea19 semantic: Report redeclaration error for import bindings
conflicting with value declarations (oxc-project#19068) (Boshen)
- 3aeba7a semantic: Report redeclaration error for `function a() {} var
a` in module mode (oxc-project#19041) (Boshen)
- 35e32c6 coverage: Match Babel's options.json inheritance for test
fixtures (oxc-project#19002) (Boshen)
- 463d60d semantic: Skip TS2391 for standalone computed-name class
methods (oxc-project#19025) (Boshen)
- 56c086b parser: Add modifier ordering validation (TS1029) (oxc-project#19024)
(Boshen)
- 6067a49 linter/jsdoc: False positive in `check-tag-names` for `@` in
email addresses and npm scopes (oxc-project#19021) (Boshen)
- b13bb70 semantic/jsdoc: Inline tags like `{@link}` break jsdoc parsing
(oxc-project#19019) (Boshen)
- e3609e3 regular_expression: Preserve UnicodeEscape CharacterKind in
string literals (oxc-project#18998) (Boshen)
- 57917ee parser: Parse decorators on rest parameters (oxc-project#18938) (Boshen)
- 487601b napi: Disable mimalloc on Windows to fix worker_threads crash
(oxc-project#18923) (Boshen)
- 1f6b193 parser: Validate TypeScript import type options (oxc-project#18889)
(Boshen)
- 1663184 parser: Allow conditional types in function type parameters
(oxc-project#18886) (Boshen)
- 5758046 parser: Error on property access after instantiation
expression (oxc-project#18887) (Boshen)
- 5eb4a94 parser: Handle `<<` as two `<` tokens in type argument
contexts (oxc-project#18885) (Boshen)

### ⚡ Performance

- ed8c054 oxc_str: Add precomputed hash to Ident for fast HashMap
lookups (oxc-project#19143) (Boshen)
- d4a0867 transformer_plugins: Switch ReplaceGlobalDefines from Traverse
to VisitMut (oxc-project#19146) (Boshen)
- 9eb16b3 syntax: Pack ASCII identifier tables into single bitflag table
(oxc-project#19088) (Boshen)
- e7595d1 mangler: Use BitSet for exported symbols set (oxc-project#19023)
(sapphi-red)
- 2537924 semantic: Optimize scope resolution with fast paths and
inlining (oxc-project#19029) (Boshen)
- 69a8d85 mangler: Use BitSet for keep_names symbols set (oxc-project#19028)
(sapphi-red)
- f78c525 parser: Try hybrid parsing for jsx children and closing
element/fragments (oxc-project#18789) (camchenry)

Co-authored-by: camc314 <[email protected]>
OskarLebuda pushed a commit to OskarLebuda/oxc that referenced this pull request Feb 17, 2026
@Boshen @OskarLebuda
perf(syntax): pack ASCII identifier tables into single bitflag table (o…
33be77e 
…xc-project#19088)

## Summary

- Replace two `[bool; 128]` tables (`ASCII_START`, `ASCII_CONTINUE` — 256 bytes, 4 cache lines) with one `[u8; 128]` bitflag table (`ASCII_ID_FLAGS` — 128 bytes, 2 cache lines)
- Each byte packs `ID_START` (bit 0) and `ID_CONTINUE` (bit 1), so both `is_identifier_start_ascii` and `is_identifier_part_ascii` hit the same cache line for any given character
- Remove `unsafe { assert_unchecked! }` calls in the bulk `is_identifier_name` by indexing the flags table directly with byte values

🤖 Generated with [Claude Code](https://claude.com/claude-code)
OskarLebuda pushed a commit to OskarLebuda/oxc that referenced this pull request Feb 17, 2026
@Boshen @camc314 @OskarLebuda
release(crates): oxc v0.113.0 (oxc-project#19210)
ea5f1e2 
### 💥 BREAKING CHANGES

- 2bf7293 mangler: [**BREAKING**] Enable `top_level` by default for
modules and commonjs (oxc-project#18278) (sapphi-red)
- 48b0542 span: [**BREAKING**] SourceType::ts should set module to
unambigious (oxc-project#18873) (Boshen)

### 🚀 Features

- 500d071 minifier: Local traverse ctx and generated minifier traverse
(oxc-project#19106) (Boshen)
- 142a1be parser: Detect binary files with TS1490 error (oxc-project#19047)
(Boshen)
- e316857 allocator/bitset: Add `Ones` iterator to `BitSet` (oxc-project#19027)
(sapphi-red)
- 742ad3f minifier: Default `invalid_import_side_effects` to `false`
(oxc-project#18916) (sapphi-red)
- 0eff6be parser: Error JSX-like type assertions and generics in
`.mts`/`.cts` (oxc-project#18910) (Boshen)
- 18320c6 span: Store file extension in `SourceType` (oxc-project#18893) (Boshen)

### 🐛 Bug Fixes

- a7514e4 isolated-declarations: Preserve const context in literal type
inference (oxc-project#19178) (camc314)
- 312e756 isolated-declarations: Preserve readonly literal initializers
(oxc-project#19177) (camc314)
- d0ca8d0 isolated-declarations: Skip parenthesis when inferring type
(oxc-project#19176) (camc314)
- 110c300 oxc_ecmascript: `+[false]` and `+[true]` should evaluate to
`NaN` (oxc-project#19174) (copilot-swe-agent)
- f32ea19 semantic: Report redeclaration error for import bindings
conflicting with value declarations (oxc-project#19068) (Boshen)
- 3aeba7a semantic: Report redeclaration error for `function a() {} var
a` in module mode (oxc-project#19041) (Boshen)
- 35e32c6 coverage: Match Babel's options.json inheritance for test
fixtures (oxc-project#19002) (Boshen)
- 463d60d semantic: Skip TS2391 for standalone computed-name class
methods (oxc-project#19025) (Boshen)
- 56c086b parser: Add modifier ordering validation (TS1029) (oxc-project#19024)
(Boshen)
- 6067a49 linter/jsdoc: False positive in `check-tag-names` for `@` in
email addresses and npm scopes (oxc-project#19021) (Boshen)
- b13bb70 semantic/jsdoc: Inline tags like `{@link}` break jsdoc parsing
(oxc-project#19019) (Boshen)
- e3609e3 regular_expression: Preserve UnicodeEscape CharacterKind in
string literals (oxc-project#18998) (Boshen)
- 57917ee parser: Parse decorators on rest parameters (oxc-project#18938) (Boshen)
- 487601b napi: Disable mimalloc on Windows to fix worker_threads crash
(oxc-project#18923) (Boshen)
- 1f6b193 parser: Validate TypeScript import type options (oxc-project#18889)
(Boshen)
- 1663184 parser: Allow conditional types in function type parameters
(oxc-project#18886) (Boshen)
- 5758046 parser: Error on property access after instantiation
expression (oxc-project#18887) (Boshen)
- 5eb4a94 parser: Handle `<<` as two `<` tokens in type argument
contexts (oxc-project#18885) (Boshen)

### ⚡ Performance

- ed8c054 oxc_str: Add precomputed hash to Ident for fast HashMap
lookups (oxc-project#19143) (Boshen)
- d4a0867 transformer_plugins: Switch ReplaceGlobalDefines from Traverse
to VisitMut (oxc-project#19146) (Boshen)
- 9eb16b3 syntax: Pack ASCII identifier tables into single bitflag table
(oxc-project#19088) (Boshen)
- e7595d1 mangler: Use BitSet for exported symbols set (oxc-project#19023)
(sapphi-red)
- 2537924 semantic: Optimize scope resolution with fast paths and
inlining (oxc-project#19029) (Boshen)
- 69a8d85 mangler: Use BitSet for keep_names symbols set (oxc-project#19028)
(sapphi-red)
- f78c525 parser: Try hybrid parsing for jsx children and closing
element/fragments (oxc-project#18789) (camchenry)

Co-authored-by: camc314 <[email protected]>
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