[DON'T MERGE] Port #[cfg] and #[cfg_attr] trace attributes to the new attribute parsers

[JonathanBrouwer]

Code is still very ugly in places, no need to review yet. Made the PR for perf

[JonathanBrouwer]

@bors try @rust-timer queue

[JonathanBrouwer]

@bors try cancel

[rust-bors]

Try build cancelled. Cancelled workflows:

• https://github.com/rust-lang/rust/actions/runs/20303060187

[JonathanBrouwer]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 42e640c (42e640c5f0c710e5113f19d4652388db81a0cff9, parent: 58b270bebef86316f70174d5a1ea4eb19ef91b62)

[rust-timer]

Finished benchmarking commit (42e640c): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@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)	0.3%	[0.1%, 0.7%]	11
Regressions ❌ (secondary)	0.2%	[0.1%, 0.3%]	4
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.2%]	1
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.1%]	9
All ❌✅ (primary)	0.3%	[-0.2%, 0.7%]	12

Max RSS (memory usage)

Results (primary 1.1%, 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)	3.1%	[3.1%, 3.1%]	1
Regressions ❌ (secondary)	2.9%	[1.0%, 4.9%]	2
Improvements ✅ (primary)	-0.8%	[-0.8%, -0.8%]	1
Improvements ✅ (secondary)	-0.8%	[-0.8%, -0.8%]	1
All ❌✅ (primary)	1.1%	[-0.8%, 3.1%]	2

Cycles

Results (primary -2.0%, secondary -2.0%)

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)	4.0%	[4.0%, 4.0%]	1
Improvements ✅ (primary)	-2.0%	[-2.0%, -2.0%]	1
Improvements ✅ (secondary)	-3.2%	[-3.8%, -2.7%]	5
All ❌✅ (primary)	-2.0%	[-2.0%, -2.0%]	1

Binary size

Results (primary -0.5%, secondary -0.2%)

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
Improvements ✅ (primary)	-0.5%	[-1.7%, -0.0%]	48
Improvements ✅ (secondary)	-0.2%	[-0.7%, -0.0%]	14
All ❌✅ (primary)	-0.5%	[-1.7%, -0.0%]	48

Bootstrap: 483.187s -> 484.445s (0.26%)
Artifact size: 390.55 MiB -> 390.58 MiB (0.01%)