Update exchange_malloc to take Alignment too

[scottmcm]

#152605 updated the shim (__rust_alloc and friends), but not the special one that box uses. So do that one too.

This is split out from #152641 in hopes of simplifying things.

r? @cjgillot

[cjgillot]

r=me if perf is ok

[scottmcm]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: ee4b7f6 (ee4b7f6be1ff7c54d2f794480518f9e5528e5034, parent: 139651428df86cf88443295542c12ea617cbb587)

[rust-timer]

Finished benchmarking commit (ee4b7f6): 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
Regressions ❌ (secondary)	0.9%	[0.5%, 1.6%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.9%	[-2.9%, -0.5%]	8
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary -6.2%)

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)	-6.2%	[-10.2%, -3.8%]	3
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-6.2%	[-10.2%, -3.8%]	3

Cycles

Results (primary -2.6%, 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)	3.1%	[2.4%, 4.0%]	3
Improvements ✅ (primary)	-2.6%	[-3.0%, -2.2%]	2
Improvements ✅ (secondary)	-2.8%	[-3.5%, -2.3%]	3
All ❌✅ (primary)	-2.6%	[-3.0%, -2.2%]	2

Binary size

Results (primary 0.8%, secondary -1.2%)

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.2%	[-2.0%, -0.4%]	11
All ❌✅ (primary)	0.8%	[0.8%, 0.8%]	1

Bootstrap: 482.657s -> 482.787s (0.03%)
Artifact size: 397.96 MiB -> 397.99 MiB (0.01%)

[scottmcm]

No changes in primary. Secondary is mixed, but overall green.

@bors r=cjgillot

[rust-bors]

📌 Commit 20b897d has been approved by cjgillot

It is now in the queue for this repository.

[RalfJung]

Ah, more conflicts for the box_new PR :/

[scottmcm]

Is that one just deleting exchange_malloc, Ralf? If so, feel free to r- this since it looks like it just got r='d.

I see the note in that one that

I'd suggest we can try passing a Layout in a future, separate PR.

so I could just change this one to be that change.

[scottmcm]

Oh, yeah, looking at compiler/rustc_mir_build/src/builder/expr/as_rvalue.rs in that PR I'll just

@bors r-

[RalfJung]

Yeah it removes the lang item, though a similar helper gets added as a regular function.

[scottmcm]

As a regular function is great! I never wanted to touch mir-build to do this :)

[rust-bors]

☔ The latest upstream changes (presumably #148190) made this pull request unmergeable. Please resolve the merge conflicts.

[scottmcm]

Closed in favour of #152737