uucore: name hardware features after the CPU instructions

[ChihweiLHBird]

Summary

HardwareFeature::PclMul and HardwareFeature::Vmull take their names from the two CRC paths that cksum --debug reports as pclmul and vmull. But they detect CPU instructions: is_x86_feature_detected!("pclmulqdq") and is_aarch64_feature_detected!("pmull"). The distinction matters because a path needs more than its instruction. For example, the pclmul path also needs AVX, so a check such as has_pclmul() && has_avx() (in a follow up PR) reads as if pclmul needs more than pclmul.

This PR renames the variants to Pclmulqdq and Pmull, with has_pclmulqdq(), has_pmull() and the detect_* functions to match. Now the enum names the instruction and cksum names the path. Behavior does not change: cksum --debug still prints pclmul and vmull, and the GLIBC_TUNABLES names and wc --debug labels stay the same but may be updated in the follow up PRs to align with GNU behaviors.

No behavior change is intended in this PR.

[Copilot]

🟢 Approval recommended

The rename is complete and preserves existing detection and output behavior.

0 open findings

What changed in this PR

Renames hardware feature APIs to match the detected CPU instructions without changing user-visible debug labels or behavior.

Changes:

• Renames PCLMULQDQ and PMULL feature variants, methods, and detectors.
• Updates cksum and wc call sites while preserving output labels.

File	Description
src/​uucore/​src/​lib/​features/​hardware.rs	Renames hardware feature APIs.
src/​uu/​cksum/​src/​cksum.rs	Uses the renamed detection methods.
src/​uu/​wc/​src/​wc.rs	Updates variants while retaining existing labels.

🧠 Review effort: Balanced

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[codspeed]

Merging this PR will degrade performance by 31.01%

⚠️ 123 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• du_all_wide_tree[(5000, 500)]
• sort_reverse_utf8_locale
• sort_mixed_utf8_locale
• sort_unique_utf8_locale
• cksum_raw_output
• sort_very_long_lines_utf8_locale
• cksum_crc
• cksum_default
• cksum_sysv
• du_wide_tree[(5000, 500)]
• …and 113 more

ℹ️ 1 benchmark has no flame graph

The flamegraph could not be generated because too much time was spent in runtime internals, making the visualization not useful for performance analysis.

• sort_dictionary_order[500000]

⚠️ 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

⚡ 2 improved benchmarks
❌ 2 regressed benchmarks
✅ 397 untouched benchmarks
⏩ 70 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	factor_three_39_bit_primes	321.7 ms	1,267.3 ms	-74.61%
❌	Simulation	factor_five_38_bit_primes	1.5 s	1.9 s	-16.92%
⚡ ⚠️	Simulation	du_all_wide_tree[(5000, 500)]	35.7 ms	34.3 ms	+4.17%
⚡	Memory	du_all_wide_tree[(5000, 500)]	1,041.8 KB	1,010.5 KB	+3.1%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing ChihweiLHBird:zhiwei/hardware-feature-names (556b621) with main (1747ba1)}

Footnotes

1. 70 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]

🟢 Approval recommended

The rename is complete and consistent, with no unresolved references or behavior changes.

0 open findings

🧠 Review effort: Balanced

[sylvestre]

with the new names, "PMULL" => Pclmulqdq looks wrong, is that intended?

[ChihweiLHBird]

Yes, it's intended to keep this as a non-behavior-change PR and avoid a large hard-to-review diff. But I do have a plan to change them later after fixing another bug it's relying on for preventing regressions.

A sample of such regression of we make the change now for the keys here:

With GLIBC_TUNABLES=glibc.cpu.hwcaps=-PMULL

GNU:           cksum: pclmul support not detected
main:          cksum: pclmul support not detected
keys changed:  cksum: using pclmul hardware support

[Copilot]

🟢 Approval recommended

The rename is complete and preserves existing behavior across all affected call sites.

0 open findings

🧠 Review effort: Balanced