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Apple: Refactor deployment target version parsing

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- Merge minimum OS version list into one function (makes it easier to
  see the logic in it).
- Parse patch deployment target versions.
- Consistently specify deployment target in LLVM target (previously
  omitted on `aarch64-apple-watchos`).
This commit is contained in:
Mads Marquart 2024-09-05 06:45:02 +02:00
parent 23cdb50e4f
commit 5b51331abe
28 changed files with 323 additions and 364 deletions
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33
compiler/rustc_codegen_ssa/src/back/metadata.rs
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@ -372,27 +372,42 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
Some(file)
}
/// Since Xcode 15 Apple's LD requires object files to contain information about what they were
/// built for (LC_BUILD_VERSION): the platform (macOS/watchOS etc), minimum OS version, and SDK
/// version. This returns a `MachOBuildVersion` for the target.
/// Mach-O files contain information about:
/// - The platform/OS they were built for (macOS/watchOS/Mac Catalyst/iOS simulator etc).
/// - The minimum OS version / deployment target.
/// - The version of the SDK they were targetting.
///
/// In the past, this was accomplished using the LC_VERSION_MIN_MACOSX, LC_VERSION_MIN_IPHONEOS,
/// LC_VERSION_MIN_TVOS or LC_VERSION_MIN_WATCHOS load commands, which each contain information
/// about the deployment target and SDK version, and implicitly, by their presence, which OS they
/// target. Simulator targets were determined if the architecture was x86_64, but there was e.g. a
/// LC_VERSION_MIN_IPHONEOS present.
///
/// This is of course brittle and limited, so modern tooling emit the LC_BUILD_VERSION load
/// command (which contains all three pieces of information in one) when the deployment target is
/// high enough, or the target is something that wouldn't be encodable with the old load commands
/// (such as Mac Catalyst, or Aarch64 iOS simulator).
///
/// Since Xcode 15, Apple's LD apparently requires object files to use this load command, so this
/// returns the `MachOBuildVersion` for the target to do so.
fn macho_object_build_version_for_target(target: &Target) -> object::write::MachOBuildVersion {
/// The `object` crate demands "X.Y.Z encoded in nibbles as xxxx.yy.zz"
/// e.g. minOS 14.0 = 0x000E0000, or SDK 16.2 = 0x00100200
fn pack_version((major, minor): (u32, u32)) -> u32 {
(major << 16) | (minor << 8)
fn pack_version((major, minor, patch): (u16, u8, u8)) -> u32 {
let (major, minor, patch) = (major as u32, minor as u32, patch as u32);
(major << 16) | (minor << 8) | patch
}
let platform =
rustc_target::spec::current_apple_platform(target).expect("unknown Apple target OS");
let min_os = rustc_target::spec::current_apple_deployment_target(target)
.expect("unknown Apple target OS");
let sdk =
let min_os = rustc_target::spec::current_apple_deployment_target(target);
let (sdk_major, sdk_minor) =
rustc_target::spec::current_apple_sdk_version(platform).expect("unknown Apple target OS");
let mut build_version = object::write::MachOBuildVersion::default();
build_version.platform = platform;
build_version.minos = pack_version(min_os);
build_version.sdk = pack_version(sdk);
build_version.sdk = pack_version((sdk_major, sdk_minor, 0));
build_version
}