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Move Apple linker args from rustc_target to rustc_codegen_ssa

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They are dependent on the deployment target and SDK version, but having
these in `rustc_target` makes it hard to introduce that dependency.
This commit is contained in:
Mads Marquart 2024-09-14 21:17:50 +02:00
parent f2becdff04
commit fb10eeb42b
2 changed files with 134 additions and 121 deletions
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122
compiler/rustc_target/src/spec/base/apple/mod.rs
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@ -3,8 +3,8 @@ use std::env;
use std::num::ParseIntError;
use crate::spec::{
Cc, DebuginfoKind, FramePointer, LinkArgs, LinkerFlavor, Lld, SplitDebuginfo, StackProbeType,
StaticCow, Target, TargetOptions, add_link_args, add_link_args_iter, cvs,
Cc, DebuginfoKind, FramePointer, LinkerFlavor, Lld, SplitDebuginfo, StackProbeType, StaticCow,
Target, TargetOptions, cvs,
};
#[cfg(test)]
@ -40,25 +40,6 @@ impl Arch {
}
}
/// The architecture name to forward to the linker.
fn ld_arch(self) -> &'static str {
// Supported architecture names can be found in the source:
// https://github.com/apple-oss-distributions/ld64/blob/ld64-951.9/src/abstraction/MachOFileAbstraction.hpp#L578-L648
match self {
Armv7k => "armv7k",
Armv7s => "armv7s",
Arm64 => "arm64",
Arm64e => "arm64e",
Arm64_32 => "arm64_32",
// ld64 doesn't understand i686, so fall back to i386 instead
//
// Same story when linking with cc, since that ends up invoking ld64.
I386 | I686 => "i386",
X86_64 => "x86_64",
X86_64h => "x86_64h",
}
}
pub(crate) fn target_arch(self) -> Cow<'static, str> {
Cow::Borrowed(match self {
Armv7k | Armv7s => "arm",
@ -116,104 +97,6 @@ impl TargetAbi {
}
}
fn pre_link_args(os: &'static str, arch: Arch, abi: TargetAbi) -> LinkArgs {
// From the man page for ld64 (`man ld`):
// > The linker accepts universal (multiple-architecture) input files,
// > but always creates a "thin" (single-architecture), standard Mach-O
// > output file. The architecture for the output file is specified using
// > the -arch option.
//
// The linker has heuristics to determine the desired architecture, but to
// be safe, and to avoid a warning, we set the architecture explicitly.
let mut args =
TargetOptions::link_args(LinkerFlavor::Darwin(Cc::No, Lld::No), &["-arch", arch.ld_arch()]);
// From the man page for ld64 (`man ld`):
// > This is set to indicate the platform, oldest supported version of
// > that platform that output is to be used on, and the SDK that the
// > output was built against. platform [...] may be one of the following
// > strings:
// > - macos
// > - ios
// > - tvos
// > - watchos
// > - bridgeos
// > - visionos
// > - xros
// > - mac-catalyst
// > - ios-simulator
// > - tvos-simulator
// > - watchos-simulator
// > - visionos-simulator
// > - xros-simulator
// > - driverkit
//
// Like with `-arch`, the linker can figure out the platform versions
// itself from the binaries being linked, but to be safe, we specify the
// desired versions here explicitly.
let platform_name: StaticCow<str> = match abi {
TargetAbi::Normal => os.into(),
TargetAbi::Simulator => format!("{os}-simulator").into(),
TargetAbi::MacCatalyst => "mac-catalyst".into(),
};
let min_version: StaticCow<str> = {
let (major, minor, patch) = deployment_target(os, arch, abi);
format!("{major}.{minor}.{patch}").into()
};
// Lie about the SDK version, we don't know it here
let sdk_version = min_version.clone();
add_link_args_iter(
&mut args,
LinkerFlavor::Darwin(Cc::No, Lld::No),
["-platform_version".into(), platform_name, min_version, sdk_version].into_iter(),
);
// We need to communicate four things to the C compiler to be able to link:
// - The architecture.
// - The operating system (and that it's an Apple platform).
// - The deployment target.
// - The environment / ABI.
//
// We'd like to use `-target` everywhere, since that can uniquely
// communicate all of these, but that doesn't work on GCC, and since we
// don't know whether the `cc` compiler is Clang, GCC, or something else,
// we fall back to other options that also work on GCC when compiling for
// macOS.
//
// Targets other than macOS are ill-supported by GCC (it doesn't even
// support e.g. `-miphoneos-version-min`), so in those cases we can fairly
// safely use `-target`. See also the following, where it is made explicit
// that the recommendation by LLVM developers is to use `-target`:
// <https://github.com/llvm/llvm-project/issues/88271>
if os == "macos" {
// `-arch` communicates the architecture.
//
// CC forwards the `-arch` to the linker, so we use the same value
// here intentionally.
add_link_args(&mut args, LinkerFlavor::Darwin(Cc::Yes, Lld::No), &[
"-arch",
arch.ld_arch(),
]);
// The presence of `-mmacosx-version-min` makes CC default to macOS,
// and it sets the deployment target.
let (major, minor, patch) = deployment_target(os, arch, abi);
let opt = format!("-mmacosx-version-min={major}.{minor}.{patch}").into();
add_link_args_iter(&mut args, LinkerFlavor::Darwin(Cc::Yes, Lld::No), [opt].into_iter());
// macOS has no environment, so with these two, we've told CC all the
// desired parameters.
//
// We avoid `-m32`/`-m64`, as this is already encoded by `-arch`.
} else {
add_link_args_iter(
&mut args,
LinkerFlavor::Darwin(Cc::Yes, Lld::No),
["-target".into(), llvm_target(os, arch, abi)].into_iter(),
);
}
args
}
/// Get the base target options, LLVM target and `target_arch` from the three
/// things that uniquely identify Rust's Apple targets: The OS, the
/// architecture, and the ABI.
@ -232,7 +115,6 @@ pub(crate) fn base(
// macOS has -dead_strip, which doesn't rely on function_sections
function_sections: false,
dynamic_linking: true,
pre_link_args: pre_link_args(os, arch, abi),
families: cvs!["unix"],
is_like_osx: true,
// LLVM notes that macOS 10.11+ and iOS 9+ default