perf(mangler): use BitSet for exported symbols set by sapphi-red · Pull Request #19023 · oxc-project/oxc

sapphi-red · 2026-02-06T05:22:50Z

Similar to #19028, use BitSet for exported symbols set.

sapphi-red · 2026-02-06T05:23:05Z

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codspeed-hq · 2026-02-06T05:28:31Z

Merging this PR will improve performance by 9.93%

⚡ 2 improved benchmarks
✅ 45 untouched benchmarks
⏩ 3 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
⚡	Simulation	`mangler[RadixUIAdoptionSection.jsx_keep_names]`	21.2 µs	20.4 µs	+4.05%
⚡	Simulation	`mangler[RadixUIAdoptionSection.jsx]`	16.1 µs	14.6 µs	+9.93%

_{Comparing 02-06-perf_mangler_use_bitset_for_exported_symbols_set (297d5c6) with main (4823b58)²}

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. ↩
No successful run was found on main (87a920d) during the generation of this report, so 4823b58 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

Boshen · 2026-02-06T07:19:55Z

Merge activity

Feb 6, 7:19 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
Feb 6, 7:20 AM UTC: Boshen added this pull request to the Graphite merge queue.
Feb 6, 7:28 AM UTC: The Graphite merge queue removed this pull request due to downstack failures on PR #18278.
Feb 6, 12:48 PM UTC: sapphi-red added this pull request to the Graphite merge queue.
Feb 6, 12:56 PM UTC: The Graphite merge queue couldn't merge this PR because it had merge conflicts.
Feb 6, 1:19 PM UTC: sapphi-red added this pull request to the Graphite merge queue.
Feb 6, 1:44 PM UTC: Merged by the Graphite merge queue.

Copilot

Pull request overview

This PR optimizes the mangler's performance by replacing FxHashSet<SymbolId> with BitSet for tracking exported symbols, similar to PR #19028 which did the same for keep_names symbols. This reduces memory allocations and eliminates hashing overhead when checking if symbols are exported.

Changes:

Replaced FxHashSet<SymbolId> with Option<BitSet> for exported symbol tracking
Refactored collect_exported_symbols to use arena-allocated HashSet and BitSet
Updated tally_slot_frequencies to accept Option<&BitSet> instead of &FxHashSet<SymbolId>

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
`tasks/track_memory_allocations/allocs_minifier.snap`	Updated memory allocation benchmarks showing net reduction of ~21 system allocations across test files
`crates/oxc_mangler/src/lib.rs`	Refactored exported symbols tracking from `FxHashSet` to `BitSet`, updated function signatures and logic to use bit operations instead of hash lookups

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Similar to #19028, use BitSet for exported symbols set.

### 💥 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]>

### 💥 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]>

Similar to oxc-project#19028, use BitSet for exported symbols set.

### 💥 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]>

sapphi-red mentioned this pull request Feb 6, 2026

feat(mangler)!: enable top_level by default for modules and commonjs #18278

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github-actions bot added the C-performance Category - Solution not expected to change functional behavior, only performance label Feb 6, 2026

sapphi-red force-pushed the 02-06-perf_mangler_use_bitset_for_exported_symbols_set branch 3 times, most recently from 7fd2b5b to 1a4c151 Compare February 6, 2026 06:35

sapphi-red force-pushed the 01-20-feat_mangler_enable_top_level_by_default_for_modules_and_commonjs branch from fc97159 to e6fad00 Compare February 6, 2026 06:35

This was referenced Feb 6, 2026

feat(tasks/benchmark): add mangler keep_names case #19026

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feat(allocator/bitset): add Ones iterator to BitSet #19027

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perf(mangler): use BitSet for keep_names symbols set #19028

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sapphi-red force-pushed the 02-06-perf_mangler_use_bitset_for_exported_symbols_set branch 2 times, most recently from eaf9933 to ef89a6a Compare February 6, 2026 06:45

sapphi-red force-pushed the 01-20-feat_mangler_enable_top_level_by_default_for_modules_and_commonjs branch from e6fad00 to b2e095e Compare February 6, 2026 06:45

sapphi-red marked this pull request as ready for review February 6, 2026 07:04

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graphite-app bot changed the base branch from 01-20-feat_mangler_enable_top_level_by_default_for_modules_and_commonjs to graphite-base/19023 February 6, 2026 08:35

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sapphi-red force-pushed the 02-06-perf_mangler_use_bitset_for_exported_symbols_set branch from ef89a6a to cc556f7 Compare February 6, 2026 09:24

sapphi-red changed the base branch from graphite-base/19023 to 01-20-feat_mangler_enable_top_level_by_default_for_modules_and_commonjs February 6, 2026 09:24

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graphite-app bot changed the base branch from 01-20-feat_mangler_enable_top_level_by_default_for_modules_and_commonjs to graphite-base/19023 February 6, 2026 12:48

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Boshen added the 0-merge Merge with Graphite Merge Queue label Feb 6, 2026

perf(mangler): use BitSet for exported symbols set (#19023)

e7595d1

Similar to #19028, use BitSet for exported symbols set.

graphite-app bot force-pushed the 02-06-perf_mangler_use_bitset_for_exported_symbols_set branch from 297d5c6 to e7595d1 Compare February 6, 2026 13:37

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This was referenced Feb 9, 2026

release(crates): oxc v0.113.0 #19167

Closed

release(crates): oxc v0.113.0 #19210

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Boshen mentioned this pull request Feb 10, 2026

release(crates): oxc v0.113.0 #19215

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OskarLebuda pushed a commit to OskarLebuda/oxc that referenced this pull request Feb 17, 2026

perf(mangler): use BitSet for exported symbols set (oxc-project#19023)

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Similar to oxc-project#19028, use BitSet for exported symbols set.

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perf(mangler): use BitSet for exported symbols set#19023

perf(mangler): use BitSet for exported symbols set#19023
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Merging this PR will improve performance by 9.93%

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