Fix linking Mac Catalyst by including LC_BUILD_VERSION in object files

[bmisiak]

Hello.

Issue #106021 prevents Rust code from being linked into Mac Catalyst applications. Apple's LD has started requiring object files to contain version information about the platform they were built for, such as:

• the "deployment target" (minimum supported OS version),
• the SDK version
• the type of the platform (macOS/iOS/catalyst/tvOS/watchOS all have a different number).

This is currently only enforced when building for Mac Catalyst.

Rust uses the object crate which added support for including this information starting with 0.31.0. I upgraded it along with thorin-dwp so that everything depends on 0.31.
Apparently 0.31 pulls in ruzstd due to a new ELF standard because its compression feature is enabled by thorin. If you find this objectionable, let me know what the best way to avoid pulling in those dependencies might be.

(object upgraded in #111413)

I then added two commits:

• The first one adds very basic, hard-coded support for calling set_macho_build_version for -macabi (Catalyst) targets, where it claims deployment target of Catalyst 14.0 and SDK of 16.2.
• The second weaves the versioning through rust_target::spec::TargetOptions, so that we can stick to specifying all target-related info in one place.

Kudos to @ara4n for writing this gist.

[rustbot]

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[rustbot]

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

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
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[workingjubilee]

It would be best to also bump object in rustc_codegen_llvm as otherwise rustc will be using two different versions of the object crate during compilation which could have unfortunate effects.

It is not necessary to change std's dependencies here because std needs backtrace to be updated first.

I have opened #111413 which does this but otherwise has some conflicting changes with your PR, so I'm quite happy to drop mine.

[petrochenkov]

Blocked on #111413.

[bmisiak]

@workingjubilee I did bump it here as well, happy to proceed either way. 👌

[workingjubilee]

typo

[ara4n]

(thanks for picking up my gist @bmisiak!)

[bmisiak]

Rebased on top of #111413 and removed the dependency changes except for the bump of ar_archive_writer, which already resolved to 0.1.4.

Two commits remain: the first one is a more basic support of injecting BUILD_VERSION for -macabi targets, the second one adds more complex changes to the Catalyst targets so that versioning can be specified in them.

@rustbot label -S-blocked +S-waiting-on-review

[petrochenkov]

Thanks!
@bors r+ rollup

[bors]

📌 Commit d816b8b has been approved by petrochenkov

It is now in the queue for this repository.

[bmisiak]

@petrochenkov Hmmm I'm finding that my std fails to link for Catalyst when llvm_target does not specify ios14.0 instead of just ios. Not quite sure why yet.

It chokes on addr2line:

Building stage1 library artifacts (aarch64-apple-darwin -> aarch64-apple-ios-macabi)
   Compiling addr2line v0.19.0
error: linking with `clang` failed: exit status: 1
 note: ld: building for Mac Catalyst, but linking in object file built for , file '/Users/bm/code/compiler-rust/build/aarch64-apple-darwin/stage1-std/aarch64-apple-ios-macabi/release/deps/std-b3e24de59aa9f617.17s2hqx9bqxs3ar4.rcgu.o' for architecture arm64
          clang: error: linker command failed with exit code 1 (use -v to see invocation)
error: could not compile `std` (lib) due to previous error

But works fine when llvm_target is arm64-apple-ios14.0-macabi.

#106925 removed the version from llvm_target because newer clang dropped support for the 13.0 catalyst target.

I might add it back in, bumping it from 13.0 to 14.0. We do specify the target when building for iOS as well.

[bmisiak]

@rustbot label -S-waiting-on-bors +S-waiting-on-review

[petrochenkov]

@bors r+

[bors]

📌 Commit a61f026 has been approved by petrochenkov

It is now in the queue for this repository.