perf(mangler): avoid ToString allocations

[camc314]

[camc314]

• perf(mangler): optimize slot assignment with pre-computed ancestor sets #17379 : 2 dependent PRs (#17381 , #17382 )
• feat(allocator/bitset): add clear method to reset all bits #17380
• perf(mangler): avoid ToString allocations #17378 👈 (View in Graphite)
• main

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[codspeed-hq]

CodSpeed Performance Report

Merging #17378 will not alter performance

_{Comparing c/12-26-perf_mangler_avoid_tostring_allocations (5d3eb53) with main (d2abc78)¹}

Summary

✅ 38 untouched
⏩ 7 skipped²

Footnotes

1. No successful run was found on main (5988dfa) during the generation of this report, so d2abc78 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 7 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. ↩

[Copilot]

Pull request overview

This PR optimizes the mangler by eliminating unnecessary ToString allocations when counting private class members. The optimization replaces a filter_map that converted element names to strings (only to discard them) with a simpler filter that only checks the is_private flag.

Key Changes:

• Simplified the private member counting logic to avoid allocating strings that are immediately discarded
• Reduced allocations by 302 for pdf.mjs benchmark (from 20495 to 20193)

Reviewed changes

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

File	Description
crates/oxc_mangler/src/lib.rs	Refactored private member counting to use filter instead of filter_map with to_string(), avoiding unnecessary string allocations
tasks/track_memory_allocations/allocs_minifier.snap	Updated allocation benchmark showing reduction from 20495 to 20193 allocations for pdf.mjs

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[graphite-app]

Merge activity

• Dec 27, 5:44 AM UTC: Boshen added this pull request to the Graphite merge queue.
• Dec 27, 5:51 AM UTC: Merged by the Graphite merge queue.