Remove legacy bitcode defaults from all Apple specs

[BlackHoleFox]

Xcode 14 deprecated bitcode with warnings and now Xcode 15 has dropped it completely. rustc should follow what the platform tooling is doing as well since it just increases binary sizes for no gain at this point.

cc made a similar change last month.

Two things show this should have minimal impact:

• Apple has stopped accepting apps built with versions of Xcode (<14) that generate bitcode
• The app store has been stripping bitcode off IPA releases for over 2 years now.

I didn't nuke all the bitcode changes added in #71970 since maybe another target in the future could need mandatory bitcode embedding.

Staticlibs built for iOS still link correctly with XCode 15 against a test app when using a compiler built from this branch.

cc @thomcc @keith

[rustbot]

r? @TaKO8Ki

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[rustbot]

These commits modify compiler targets.
(See the Target Tier Policy.)

[BlackHoleFox]

One open question: Should the Apple-specific bitcode_section_name logic be removed here too? I don't know if other uses/tools for bitcode outside of App Store distribution need the Apple-specific name or just the generic LLVM bitcode section name.

[keith]

awesome cleanup!

[keith]

One open question: Should the Apple-specific bitcode_section_name logic be removed here too? I don't know if other uses/tools for bitcode outside of App Store distribution need the Apple-specific name or just the generic LLVM bitcode section name.

I don't think that's safe to remove unless the embed_bitcode logic can be removed entirely. If a Mach-O object ever has embedded bitcode I do think it has to be in the apple specific section.

[TaKO8Ki]

It's better to re-roll it r? compiler

[BlackHoleFox]

Rebased to remove conflicts.

[davidtwco]

LGTM, if there are more parts that you can remove and that were only used by these targets, then I think you should feel free to do so - they can always be resurrected from the Git history if reqd - but I'll approve and merge this for now and that can be for a follow-up.

[davidtwco]

@bors r+ rollup

[bors]

📌 Commit b27c3b7 has been approved by davidtwco

It is now in the queue for this repository.

[bors]

⌛ Testing commit b27c3b7 with merge 7d0e1bc...

[bors]

☀️ Test successful - checks-actions
Approved by: davidtwco
Pushing 7d0e1bc to master...

[rust-timer]

Finished benchmarking commit (7d0e1bc): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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
Regressions ❌ (secondary)	0.4%	[0.4%, 0.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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)	2.8%	[2.8%, 2.8%]	1
Regressions ❌ (secondary)	4.3%	[4.3%, 4.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.4%	[-4.4%, -4.4%]	1
All ❌✅ (primary)	2.8%	[2.8%, 2.8%]	1

Cycles

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

Binary size

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

Bootstrap: 675.196s -> 674.69s (-0.07%)
Artifact size: 313.81 MiB -> 313.81 MiB (-0.00%)