Print regions in type_name.

[nnethercote]

Currently they are skipped, which is a bit weird, and it sometimes causes malformed output like Foo<> and dyn Bar<, A = u32>.

Most regions are erased by the time type_name does its work. So all regions are now printed as '_ in non-optional places. Not perfect, but better than the status quo.

c_name is updated to trim lifetimes from MIR pass names, so that the PASS_NAMES sanity check still works. It is also renamed as simplify_pass_type_name and made non-const, because it doesn't need to be const and the non-const implementation is much shorter.

The commit also renames should_print_region as should_print_optional_region, which makes it clearer that it only applies to some regions.

Fixes #145168.

r? @lcnr

[rustbot]

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[nnethercote]

@lcnr: new code is up. Quite a bit has changed.

@rustbot ready

[nnethercote]

I updated again. c_name is now non-const, which is much nicer, and renamed as simplify_pass_type_name.

@rustbot ready

[lcnr]

I updated again. c_name is now non-const, which is much nicer, and renamed as simplify_pass_type_name.

@rustbot ready

i would expect that we've done it in a const block for 👻 perf 👻 reasons? 🤔

@bors2 try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: fc05a4f (fc05a4f44af11286e3ae4b0ab02b85685f709d2b, parent: 1553adfe6884a8f6c28f5a673d3e605535ee0113)

[rust-timer]

Finished benchmarking commit (fc05a4f): 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)	1.0%	[0.2%, 4.3%]	70
Regressions ❌ (secondary)	1.2%	[0.1%, 5.3%]	57
Improvements ✅ (primary)	-1.4%	[-1.4%, -1.4%]	1
Improvements ✅ (secondary)	-0.5%	[-1.4%, -0.0%]	3
All ❌✅ (primary)	0.9%	[-1.4%, 4.3%]	71

Max RSS (memory usage)

Results (secondary 4.2%)

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)	4.2%	[1.7%, 5.6%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 3.0%)

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%	[3.0%, 6.0%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-5.8%	[-5.8%, -5.8%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 464.093s -> 466.402s (0.50%)
Artifact size: 377.76 MiB -> 377.46 MiB (-0.08%)

[bors]

☔ The latest upstream changes (presumably #145366) made this pull request unmergeable. Please resolve the merge conflicts.

[rust-timer]

Finished benchmarking commit (28ae7e3): comparison URL.

Overall result: ❌ regressions - 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%	[0.2%, 0.5%]	12
Regressions ❌ (secondary)	0.5%	[0.2%, 2.0%]	17
Improvements ✅ (primary)	-0.7%	[-0.7%, -0.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-0.7%, 0.5%]	13

Max RSS (memory usage)

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

Cycles

Results (secondary -0.9%)

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)	1.6%	[1.6%, 1.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.3%	[-3.3%, -3.3%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.1%, 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)	0.9%	[0.9%, 0.9%]	1
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.1%]	3
Improvements ✅ (secondary)	-0.4%	[-0.7%, -0.1%]	6
All ❌✅ (primary)	-0.1%	[-0.1%, -0.1%]	3

Bootstrap: 468.653s -> 469.476s (0.18%)
Artifact size: 377.36 MiB -> 377.32 MiB (-0.01%)

[nnethercote]

Thanks for the review comments! This one needed a lot of work.

@bors r=lcnr

[bors]

📌 Commit 75552ef has been approved by lcnr

It is now in the queue for this repository.

[theemathas]

I assume that this type_name output is acceptable?

use std::any::type_name;

macro_rules! t {
    ($ty:ty, $str:literal) => {
        assert_eq!(type_name::<$ty>(), $str);
    };
}

trait Trait<'a> {}
#[allow(dead_code)]
struct Thing<'a>(&'a i32);

fn main() {
    t!(dyn for<'a> Trait<'a>, "dyn foo::Trait<'_>");
    t!(dyn Trait<'static>, "dyn foo::Trait<'_>");
    t!(fn(Thing<'static>), "fn(foo::Thing<'_>)");
    t!(for<'a> fn(Thing<'a>), "fn(foo::Thing<'_>)");
}

[lcnr]

are the remaining regressions spurious? It looks like it's still perf negative 🤔 :x

[lcnr]

@bors r-

[lcnr]

I assume that this type_name output is acceptable?

use std::any::type_name;

macro_rules! t {
    ($ty:ty, $str:literal) => {
        assert_eq!(type_name::<$ty>(), $str);
    };
}

trait Trait<'a> {}
#[allow(dead_code)]
struct Thing<'a>(&'a i32);

fn main() {
    t!(dyn for<'a> Trait<'a>, "dyn foo::Trait<'_>");
    t!(dyn Trait<'static>, "dyn foo::Trait<'_>");
    t!(fn(Thing<'static>), "fn(foo::Thing<'_>)");
    t!(for<'a> fn(Thing<'a>), "fn(foo::Thing<'_>)");
}

yeah, not ideal, but better than the status quo at lesat 😁

[nnethercote]

I reinstated the MirLint const.

@bors r=lcnr

[bors]

📌 Commit 00492e3 has been approved by lcnr

It is now in the queue for this repository.

[nnethercote]

@bors r-

[rustbot]

⚠️ Warning ⚠️

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  Please move them to the PR description, to avoid spamming the issues with references to the commit, and so this bot can automatically canonicalize them to avoid issues with subtree.
  • 8296ad0

[nnethercote]

I fixed the submodules. Maybe this time it'll be ok? :)

@bors r=lcnr

[bors]

📌 Commit 8296ad0 has been approved by lcnr

It is now in the queue for this repository.