Use u64 for incr comp allocation offsets

[saethlin]

Fixes #76037
Fixes #95780
Fixes #111613

These issues are all reporting ICEs caused by using u32 to store offsets to allocations in the incremental compilation cache. This PR aims to lift that limitation by changing the offset type in question to u64.

There are two perf runs in this PR. The first reports a regression, and the second does not. The changes are the same in both. I rebased the PR then did the second perf run because I noticed that the primary regression in it was very commonly seen in spurious regression reports.

I do not know what the perf run will report when this is merged. I would not be surprised to see regression or neutral, but the cachegrind diffs for the regression point at try_mark_previous_green which is a common source of inexplicable regressions and I don't think should be perturbed by this PR.

I'm not opposed to adding a regression test such as

fn main() {
    println!("{}", [37; 1 << 30].len());
}

But that program takes 1 minute to compile and consumes 4.6 GB of memory then writes that much to disk. Is that a concerning amount of resource use for a test?

r? @nnethercote

[saethlin]

@bors try @rust-timer queue

[bors]

⌛ Trying commit c157ed5ebb2c7a774fe4e33032261f4ec5335dad with merge 95e855e355817d2ab0983eae1b0c1c2bc192b552...

[bors]

☀️ Try build successful - checks-actions
Build commit: 95e855e355817d2ab0983eae1b0c1c2bc192b552 (95e855e355817d2ab0983eae1b0c1c2bc192b552)

[rust-timer]

Finished benchmarking commit (95e855e355817d2ab0983eae1b0c1c2bc192b552): comparison URL.

Overall result: ❌ regressions - 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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

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

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.5%, 1.2%]	36
Regressions ❌ (secondary)	0.7%	[0.4%, 0.8%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.8%	[0.5%, 1.2%]	36

Max RSS (memory usage)

Results

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)	4.7%	[4.7%, 4.7%]	1
Improvements ✅ (primary)	-1.0%	[-1.0%, -1.0%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.0%	[-1.0%, -1.0%]	1

Cycles

Results

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)	3.4%	[1.2%, 5.0%]	8
Regressions ❌ (secondary)	2.5%	[2.5%, 2.5%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.4%	[1.2%, 5.0%]	8

Binary size

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

Bootstrap: 656.708s -> 657.823s (0.17%)

[saethlin]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 752f2857bf8e77932ff8f05d8194f36494714949 with merge 895ebafae6f9467924efe5ea4721c573424631c0...

[bors]

☀️ Try build successful - checks-actions
Build commit: 895ebafae6f9467924efe5ea4721c573424631c0 (895ebafae6f9467924efe5ea4721c573424631c0)

[rust-timer]

Finished benchmarking commit (895ebafae6f9467924efe5ea4721c573424631c0): comparison URL.

Overall result: no relevant changes - 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 benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

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)	2.4%	[2.4%, 2.4%]	1
Regressions ❌ (secondary)	6.1%	[6.1%, 6.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-3.3%, -2.6%]	4
All ❌✅ (primary)	2.4%	[2.4%, 2.4%]	1

Cycles

Results

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)	-	-	0
Improvements ✅ (primary)	-2.5%	[-2.7%, -2.3%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.5%	[-2.7%, -2.3%]	2

Binary size

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

Bootstrap: 658.555s -> 658.567s (0.00%)

[rustbot]

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

[oli-obk]

But that program takes 1 minute to compile and consumes 4.6 GB of memory then writes that much to disk. Is that a concerning amount of resource use for a test?

Yea that seems not great. But I also don't think it's too useful a test, as it is hard to regress again

[RalfJung]

Should there be a comment somewhere explaining why u64 is needed?

[nnethercote]

Should there be a comment somewhere explaining why u64 is needed?

Indeed, there are no comments in the commit and no explanation in the PR. What's the motivation here?

[nnethercote]

@bors r+

[bors]

📌 Commit 4e117a9 has been approved by nnethercote

It is now in the queue for this repository.

[bors]

⌛ Testing commit 4e117a9 with merge 6f65ef5...

[bors]

☀️ Test successful - checks-actions
Approved by: nnethercote
Pushing 6f65ef5 to master...

[rust-timer]

Finished benchmarking commit (6f65ef5): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results

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)	0.7%	[0.7%, 0.7%]	1
Improvements ✅ (primary)	-3.5%	[-3.5%, -3.5%]	1
Improvements ✅ (secondary)	-2.0%	[-2.0%, -2.0%]	1
All ❌✅ (primary)	-3.5%	[-3.5%, -3.5%]	1

Binary size

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

Bootstrap: 657.644s -> 656.437s (-0.18%)