compiler: replace few consts arrays with statics to remove const dupes by klensy · Pull Request #136191 · rust-lang/rust

klensy · 2025-01-28T14:56:05Z

Locally on x86_64-pc-windows-msvc -100kb for rustc_driver.dll

rustbot · 2025-01-28T14:56:15Z

rustbot has assigned @SparrowLii.
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rustbot · 2025-01-28T14:56:17Z

These commits modify compiler targets.
(See the Target Tier Policy.)

compiler-errors · 2025-01-28T15:31:52Z

probably no perf implications?

@bors try @rust-timer queue

bors · 2025-01-28T15:33:13Z

⌛ Trying commit dc62b8f with merge 3e5336e...

compiler: replace few consts arrays with statics to remove const dupes Locally on `x86_64-pc-windows-msvc` -100kb for `rustc_driver.dll`

bors · 2025-01-28T17:25:13Z

☀️ Try build successful - checks-actions
Build commit: 3e5336e (3e5336e798a13f3872d2da1cc374610b260b877e)

rust-timer · 2025-01-28T19:49:06Z

Finished benchmarking commit (3e5336e): comparison URL.

Overall result: ❌✅ regressions and improvements - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.3%	[0.2%, 0.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary -0.9%, secondary 1.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.1%	[1.0%, 3.4%]	4
Improvements ✅ (primary)	-0.9%	[-0.9%, -0.9%]	1
Improvements ✅ (secondary)	-1.1%	[-1.6%, -0.6%]	2
All ❌✅ (primary)	-0.9%	[-0.9%, -0.9%]	1

Cycles

Results (primary 3.0%, secondary -0.2%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.0%	[3.0%, 3.0%]	1
Regressions ❌ (secondary)	2.6%	[2.6%, 2.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-3.0%, -3.0%]	1
All ❌✅ (primary)	3.0%	[3.0%, 3.0%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 773.088s -> 773.417s (0.04%)
Artifact size: 328.30 MiB -> 326.30 MiB (-0.61%)

klensy · 2025-01-31T09:28:14Z

Less effect on linux target, about ~50kb, until next size increase, when alignment will strike back.

@rustbot ready

compiler-errors · 2025-02-06T18:03:47Z

@bors r+ rollup

bors · 2025-02-06T18:03:50Z

📌 Commit dc62b8f has been approved by compiler-errors

It is now in the queue for this repository.

compiler: replace few consts arrays with statics to remove const dupes Locally on `x86_64-pc-windows-msvc` -100kb for `rustc_driver.dll`

…iaskrgr Rollup of 9 pull requests Successful merges: - rust-lang#135973 (fix tail call checks wrt `#[track_caller]`) - rust-lang#136191 (compiler: replace few consts arrays with statics to remove const dupes) - rust-lang#136565 (compiler: Clean up weird `rustc_abi` reexports) - rust-lang#136582 (Revert "CI: build FreeBSD artifacts on FreeBSD 13.4") - rust-lang#136592 (Make sure we don't overrun the stack in canonicalizer) - rust-lang#136627 (MIR validation: add comment explaining the limitations of CfgChecker) - rust-lang#136634 (Stabilise `Cursor::{get_mut, set_position}` in `const` scenarios.) - rust-lang#136643 (ping me for attribute-related changes) - rust-lang#136644 (Add `rustc_hir_pretty::item_to_string` function) r? `@ghost` `@rustbot` modify labels: rollup

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#135973 (fix tail call checks wrt `#[track_caller]`) - rust-lang#136191 (compiler: replace few consts arrays with statics to remove const dupes) - rust-lang#136565 (compiler: Clean up weird `rustc_abi` reexports) - rust-lang#136582 (Revert "CI: build FreeBSD artifacts on FreeBSD 13.4") - rust-lang#136627 (MIR validation: add comment explaining the limitations of CfgChecker) - rust-lang#136634 (Stabilise `Cursor::{get_mut, set_position}` in `const` scenarios.) - rust-lang#136643 (ping me for attribute-related changes) - rust-lang#136644 (Add `rustc_hir_pretty::item_to_string` function) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#136191 - klensy:const_a, r=compiler-errors compiler: replace few consts arrays with statics to remove const dupes Locally on `x86_64-pc-windows-msvc` -100kb for `rustc_driver.dll`

RalfJung · 2025-06-12T12:34:55Z

compiler/rustc_target/src/target_features.rs

So randomly about half the arrays in this file are now const and the other half is static. And there's no comment explaining the reason behind this, or what one should do when adding more elements to one of these arrays, or when adding a new array. I am quite confused...

Any subjectively "big" arrays become statics, while short ones with few elements left as they was. They still can be converted into statics, but at time of this pr, it wasn't worth it.

replaces few consts with statics to reduce readonly section

dc62b8f

rustbot assigned SparrowLii Jan 28, 2025

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jan 28, 2025

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 28, 2025

compiler-errors assigned compiler-errors and unassigned SparrowLii Jan 28, 2025

bors added a commit to rust-lang-ci/rust that referenced this pull request Jan 28, 2025

Auto merge of rust-lang#136191 - klensy:const_a, r=<try>

3e5336e

compiler: replace few consts arrays with statics to remove const dupes Locally on `x86_64-pc-windows-msvc` -100kb for `rustc_driver.dll`

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 28, 2025

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 6, 2025

matthiaskrgr mentioned this pull request Feb 6, 2025

Rollup of 9 pull requests #136655

Closed

matthiaskrgr mentioned this pull request Feb 7, 2025

Rollup of 8 pull requests #136684

Merged

bors merged commit 3ce7d9c into rust-lang:master Feb 7, 2025
7 checks passed

rustbot added this to the 1.86.0 milestone Feb 7, 2025

RalfJung reviewed Jun 12, 2025

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klensy commented Jan 28, 2025

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rust-timer commented Jan 28, 2025

Overall result: ❌✅ regressions and improvements - no action needed

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Cycles

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klensy commented Jan 31, 2025

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compiler-errors commented Feb 6, 2025

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