perf(core): optimize create module hashes

[LingyuCoder]

Summary

• avoid constructing a temporary RuntimeSpec when filtering a singleton runtime
• lazily allocate the exports-info cycle-detection set only when nested exports are traversed
• keep concatenated module hash inputs as RspackHashDigest values instead of converting them to owned strings
• preserve generated output while reducing allocation and hashing overhead in create module hashes

Callgrind measurement on the React 10k production fixture without minification reduced the create module hashes stage from 705,923,691 IR to 557,307,083 IR, a 21.05% reduction. The baseline and optimized builds produced byte-identical output across all 19 emitted files.

Related links

N/A

Verification

• cargo fmt --all -- --check
• pnpm run build:binding:dev
• pnpm run test:unit
• byte-for-byte comparison of the React 10k production output

Checklist

• Tests updated (not required; existing unit coverage and output comparison verify the behavior).
• Documentation updated (not required; no user-facing behavior changes).

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-30T07:24:29.434945Z	90f2db7	PR opened

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[github-actions]

📦 Binary Size-limit

Comparing 90f2db7 to perf(ids): optimize deterministic module id assignment (#15393) by harpsealjs

❌ Size increased by 4.00KB from 68.30MB to 68.30MB (⬆️0.01%)

[github-actions]

Rsdoctor Bundle Diff Analysis

Found 5 projects in monorepo, 0 projects with changes.

📊 Quick Summary

Project	Total Size	Gzip Size	Change	Gzip Change
popular-libs	1.7 MB	556.5 KB	0	0
react-10k	5.6 MB	1.3 MB	0	0
react-1k	823.1 KB	218.4 KB	0	0
react-5k	2.7 MB	669.3 KB	0	0
ui-components	4.9 MB	1.4 MB	0	0

Generated by Rsdoctor GitHub Action

[codspeed-hq]

Merging this PR will improve performance by 14.91%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 49 untouched benchmarks
⏩ 47 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	rust@create_module_hashes	8.4 ms	7.3 ms	+14.91%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing seal/optimize-create-module-hashes (90f2db7) with main (f281cc9)}

Footnotes

1. 47 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. ↩