Reduce AttributeKind from 40 to 32 bytes

[mejrs]

@bors try @rust-timer queue

[rust-log-analyzer]

The job tidy failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

fmt check
Diff in /checkout/compiler/rustc_passes/src/stability.rs:217:
     }
 
     let const_stable_indirect = find_attr!(tcx, def_id, RustcConstStableIndirect);
-    let const_stab =
-        find_attr!(tcx, def_id, RustcConstStability { stability } => *stability);
+    let const_stab = find_attr!(tcx, def_id, RustcConstStability { stability } => *stability);
 
     // After checking the immediate attributes, get rid of the span and compute implied
     // const stability: inherit feature gate from regular stability.
Diff in /checkout/compiler/rustc_passes/src/stability.rs:387:
         if let Some(fn_sig) = fn_sig
             && !fn_sig.header.is_const()
             && const_stab.is_some()
-            && find_attr!(attrs, RustcConstStability{..})
+            && find_attr!(attrs, RustcConstStability { .. })
         {
             self.tcx.dcx().emit_err(errors::MissingConstErr { fn_sig_span: fn_sig.span });
         }
Diff in /checkout/compiler/rustc_passes/src/stability.rs:397:
             && let Some(fn_sig) = fn_sig
             && const_stab.is_const_stable()
             && !stab.is_some_and(|s| s.is_stable())
-            && find_attr!( attrs, RustcConstStability {..})
+            && find_attr!(attrs, RustcConstStability { .. })
         {
-            self.tcx
-                .dcx()
-                .emit_err(errors::ConstStableNotStable { fn_sig_span: fn_sig.span });
+            self.tcx.dcx().emit_err(errors::ConstStableNotStable { fn_sig_span: fn_sig.span });
         }
 
         if let Some(stab) = &const_stab
Diff in /checkout/compiler/rustc_passes/src/stability.rs:408:
             && stab.is_const_stable()
             && stab.const_stable_indirect
-            && find_attr!(attrs, RustcConstStability {..})
+            && find_attr!(attrs, RustcConstStability { .. })
         {
-            self.tcx.dcx().emit_err(errors::RustcConstStableIndirectPairing { span: rustc_span::DUMMY_SP });
+            self.tcx
+                .dcx()
+                .emit_err(errors::RustcConstStableIndirectPairing { span: rustc_span::DUMMY_SP });
         }
     }
 
fmt: checked 6819 files
Bootstrap failed while executing `test src/tools/tidy tidyselftest --extra-checks=py,cpp,js,spellcheck`

[JonathanBrouwer]

Fyi I tried this a while ago both with size 24 and 32, and both were perf regressions, which really surprised me.
But it's always a good idea to re-check :)

[JonathanBrouwer]

See #151507

[JonathanBrouwer]

Hmm your diff is a lot smaller so this might have some potential

[mejrs]

I have another commit lined up that does it without boxing anything, by removing deprecated's Span.

The only user facing place where we need its span is in check_attr, where it lints for USELESS_DEPRECATED. Maybe we can move that to parsing. The other uses are in this lint pass with the stability attributes, where I don't care about nice spans.

We should probably do a pass and see which spans are actually still used. They won't matter for AttributeKind's size though.

[rust-bors]

☀️ Try build successful (CI)
Build commit: 7f7461f (7f7461f22d1b2f465da5284d319e2a32dbd1b4a5, parent: fb76025f2fe6a1c8ce03fe0931f941c8077a2c34)

[JonathanBrouwer]

@rust-timer build 7f7461f

It doesn't listen to pr descriptions :)

[rust-timer]

Finished benchmarking commit (7f7461f): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.1%, 0.2%]	3
Regressions ❌ (secondary)	0.2%	[0.2%, 0.3%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.1%, 0.2%]	3

Max RSS (memory usage)

Results (primary -0.6%, secondary 1.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.8%, 0.8%]	1
Regressions ❌ (secondary)	4.4%	[0.7%, 6.5%]	4
Improvements ✅ (primary)	-2.0%	[-2.0%, -2.0%]	1
Improvements ✅ (secondary)	-1.9%	[-2.7%, -1.0%]	3
All ❌✅ (primary)	-0.6%	[-2.0%, 0.8%]	2

Cycles

Results (secondary 6.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	6.8%	[3.3%, 10.3%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

Results (secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Bootstrap: 487.131s -> 488.874s (0.36%)
Artifact size: 394.07 MiB -> 394.17 MiB (0.03%)