rustc_target/spec/base/apple/mod.rs
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use std::borrow::Cow;
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,
};
#[cfg(test)]
mod tests;
use Arch::*;
#[allow(non_camel_case_types)]
#[derive(Copy, Clone, PartialEq)]
pub(crate) enum Arch {
Armv7k,
Armv7s,
Arm64,
Arm64e,
Arm64_32,
I386,
I686,
X86_64,
X86_64h,
}
impl Arch {
fn target_name(self) -> &'static str {
match self {
Armv7k => "armv7k",
Armv7s => "armv7s",
Arm64 => "arm64",
Arm64e => "arm64e",
Arm64_32 => "arm64_32",
I386 => "i386",
I686 => "i686",
X86_64 => "x86_64",
X86_64h => "x86_64h",
}
}
/// 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",
Arm64 | Arm64e | Arm64_32 => "aarch64",
I386 | I686 => "x86",
X86_64 | X86_64h => "x86_64",
})
}
fn target_cpu(self, abi: TargetAbi) -> &'static str {
match self {
Armv7k => "cortex-a8",
Armv7s => "swift", // iOS 10 is only supported on iPhone 5 or higher.
Arm64 => match abi {
TargetAbi::Normal => "apple-a7",
TargetAbi::Simulator => "apple-a12",
TargetAbi::MacCatalyst => "apple-a12",
},
Arm64e => "apple-a12",
Arm64_32 => "apple-s4",
// Only macOS 10.12+ is supported, which means
// all x86_64/x86 CPUs must be running at least penryn
// https://github.com/llvm/llvm-project/blob/01f924d0e37a5deae51df0d77e10a15b63aa0c0f/clang/lib/Driver/ToolChains/Arch/X86.cpp#L79-L82
I386 | I686 => "penryn",
X86_64 => "penryn",
// Note: `core-avx2` is slightly more advanced than `x86_64h`, see
// comments (and disabled features) in `x86_64h_apple_darwin` for
// details. It is a higher baseline then `penryn` however.
X86_64h => "core-avx2",
}
}
fn stack_probes(self) -> StackProbeType {
match self {
Armv7k | Armv7s => StackProbeType::None,
Arm64 | Arm64e | Arm64_32 | I386 | I686 | X86_64 | X86_64h => StackProbeType::Inline,
}
}
}
#[derive(Copy, Clone, PartialEq)]
pub(crate) enum TargetAbi {
Normal,
Simulator,
MacCatalyst,
}
impl TargetAbi {
fn target_abi(self) -> &'static str {
match self {
Self::Normal => "",
Self::MacCatalyst => "macabi",
Self::Simulator => "sim",
}
}
}
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.
pub(crate) fn base(
os: &'static str,
arch: Arch,
abi: TargetAbi,
) -> (TargetOptions, StaticCow<str>, StaticCow<str>) {
let opts = TargetOptions {
abi: abi.target_abi().into(),
os: os.into(),
cpu: arch.target_cpu(abi).into(),
link_env_remove: link_env_remove(os),
vendor: "apple".into(),
linker_flavor: LinkerFlavor::Darwin(Cc::Yes, Lld::No),
// 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
// to v4, so we do the same.
// https://github.com/llvm/llvm-project/blob/378778a0d10c2f8d5df8ceff81f95b6002984a4b/clang/lib/Driver/ToolChains/Darwin.cpp#L1203
default_dwarf_version: 4,
frame_pointer: FramePointer::Always,
has_rpath: true,
dll_suffix: ".dylib".into(),
archive_format: "darwin".into(),
// Thread locals became available with iOS 8 and macOS 10.7,
// and both are far below our minimum.
has_thread_local: true,
abi_return_struct_as_int: true,
emit_debug_gdb_scripts: false,
eh_frame_header: false,
stack_probes: arch.stack_probes(),
debuginfo_kind: DebuginfoKind::DwarfDsym,
// The historical default for macOS targets is to run `dsymutil` which
// generates a packed version of debuginfo split from the main file.
split_debuginfo: SplitDebuginfo::Packed,
supported_split_debuginfo: Cow::Borrowed(&[
SplitDebuginfo::Packed,
SplitDebuginfo::Unpacked,
SplitDebuginfo::Off,
]),
// This environment variable is pretty magical but is intended for
// producing deterministic builds. This was first discovered to be used
// by the `ar` tool as a way to control whether or not mtime entries in
// the archive headers were set to zero or not. It appears that
// eventually the linker got updated to do the same thing and now reads
// this environment variable too in recent versions.
//
// For some more info see the commentary on #47086
link_env: Cow::Borrowed(&[(Cow::Borrowed("ZERO_AR_DATE"), Cow::Borrowed("1"))]),
..Default::default()
};
(opts, llvm_target(os, arch, abi), arch.target_arch())
}
pub fn sdk_version(platform: u32) -> Option<(u16, u8)> {
// NOTE: These values are from an arbitrary point in time but shouldn't make it into the final
// binary since the final link command will have the current SDK version passed to it.
match platform {
object::macho::PLATFORM_MACOS => Some((13, 1)),
object::macho::PLATFORM_IOS
| object::macho::PLATFORM_IOSSIMULATOR
| object::macho::PLATFORM_TVOS
| object::macho::PLATFORM_TVOSSIMULATOR
| object::macho::PLATFORM_MACCATALYST => Some((16, 2)),
object::macho::PLATFORM_WATCHOS | object::macho::PLATFORM_WATCHOSSIMULATOR => Some((9, 1)),
// FIXME: Upgrade to `object-rs` 0.33+ implementation with visionOS platform definition
11 | 12 => Some((1, 0)),
_ => None,
}
}
pub fn platform(target: &Target) -> Option<u32> {
Some(match (&*target.os, &*target.abi) {
("macos", _) => object::macho::PLATFORM_MACOS,
("ios", "macabi") => object::macho::PLATFORM_MACCATALYST,
("ios", "sim") => object::macho::PLATFORM_IOSSIMULATOR,
("ios", _) => object::macho::PLATFORM_IOS,
("watchos", "sim") => object::macho::PLATFORM_WATCHOSSIMULATOR,
("watchos", _) => object::macho::PLATFORM_WATCHOS,
("tvos", "sim") => object::macho::PLATFORM_TVOSSIMULATOR,
("tvos", _) => object::macho::PLATFORM_TVOS,
// FIXME: Upgrade to `object-rs` 0.33+ implementation with visionOS platform definition
("visionos", "sim") => 12,
("visionos", _) => 11,
_ => return None,
})
}
/// Hack for calling `deployment_target` outside of this module.
pub fn deployment_target_for_target(target: &Target) -> (u16, u8, u8) {
let arch = if target.llvm_target.starts_with("arm64e") {
Arch::Arm64e
} else if target.arch == "aarch64" {
Arch::Arm64
} else {
// Dummy architecture, only used by `deployment_target` anyhow
Arch::X86_64
};
let abi = match &*target.abi {
"macabi" => TargetAbi::MacCatalyst,
"sim" => TargetAbi::Simulator,
"" => TargetAbi::Normal,
abi => unreachable!("invalid abi '{abi}' for Apple target"),
};
deployment_target(&target.os, arch, abi)
}
/// Get the deployment target based on the standard environment variables, or
/// fall back to a sane default.
fn deployment_target(os: &str, arch: Arch, abi: TargetAbi) -> (u16, u8, u8) {
// When bumping a version in here, remember to update the platform-support
// docs too.
//
// NOTE: If you are looking for the default deployment target, prefer
// `rustc --print deployment-target`, as the default here may change in
// future `rustc` versions.
// Minimum operating system versions currently supported by `rustc`.
let os_min = match os {
"macos" => (10, 12, 0),
"ios" => (10, 0, 0),
"tvos" => (10, 0, 0),
"watchos" => (5, 0, 0),
"visionos" => (1, 0, 0),
_ => unreachable!("tried to get deployment target for non-Apple platform"),
};
// On certain targets it makes sense to raise the minimum OS version.
//
// This matches what LLVM does, see:
// <https://github.com/llvm/llvm-project/blob/llvmorg-18.1.8/llvm/lib/TargetParser/Triple.cpp#L1900-L1932>
let min = match (os, arch, abi) {
("macos", Arch::Arm64 | Arch::Arm64e, _) => (11, 0, 0),
("ios", Arch::Arm64 | Arch::Arm64e, TargetAbi::MacCatalyst) => (14, 0, 0),
("ios", Arch::Arm64 | Arch::Arm64e, TargetAbi::Simulator) => (14, 0, 0),
("ios", Arch::Arm64e, TargetAbi::Normal) => (14, 0, 0),
// Mac Catalyst defaults to 13.1 in Clang.
("ios", _, TargetAbi::MacCatalyst) => (13, 1, 0),
("tvos", Arch::Arm64 | Arch::Arm64e, TargetAbi::Simulator) => (14, 0, 0),
("watchos", Arch::Arm64 | Arch::Arm64e, TargetAbi::Simulator) => (7, 0, 0),
_ => os_min,
};
// The environment variable used to fetch the deployment target.
let env_var = match os {
"macos" => "MACOSX_DEPLOYMENT_TARGET",
"ios" => "IPHONEOS_DEPLOYMENT_TARGET",
"watchos" => "WATCHOS_DEPLOYMENT_TARGET",
"tvos" => "TVOS_DEPLOYMENT_TARGET",
"visionos" => "XROS_DEPLOYMENT_TARGET",
_ => unreachable!("tried to get deployment target env var for non-Apple platform"),
};
if let Ok(deployment_target) = env::var(env_var) {
match parse_version(&deployment_target) {
// It is common that the deployment target is set too low, e.g. on
// macOS Aarch64 to also target older x86_64, the user may set a
// lower deployment target than supported.
//
// To avoid such issues, we silently raise the deployment target
// here.
// FIXME: We want to show a warning when `version < os_min`.
Ok(version) => version.max(min),
// FIXME: Report erroneous environment variable to user.
Err(_) => min,
}
} else {
min
}
}
/// Generate the target triple that we need to pass to LLVM and/or Clang.
fn llvm_target(os: &str, arch: Arch, abi: TargetAbi) -> StaticCow<str> {
// The target triple depends on the deployment target, and is required to
// enable features such as cross-language LTO, and for picking the right
// Mach-O commands.
//
// Certain optimizations also depend on the deployment target.
let (major, minor, patch) = deployment_target(os, arch, abi);
let arch = arch.target_name();
// Convert to the "canonical" OS name used by LLVM:
// https://github.com/llvm/llvm-project/blob/llvmorg-18.1.8/llvm/lib/TargetParser/Triple.cpp#L236-L282
let os = match os {
"macos" => "macosx",
"ios" => "ios",
"watchos" => "watchos",
"tvos" => "tvos",
"visionos" => "xros",
_ => unreachable!("tried to get LLVM target OS for non-Apple platform"),
};
let environment = match abi {
TargetAbi::Normal => "",
TargetAbi::MacCatalyst => "-macabi",
TargetAbi::Simulator => "-simulator",
};
format!("{arch}-apple-{os}{major}.{minor}.{patch}{environment}").into()
}
fn link_env_remove(os: &'static str) -> StaticCow<[StaticCow<str>]> {
// Apple platforms only officially support macOS as a host for any compilation.
//
// If building for macOS, we go ahead and remove any erroneous environment state
// that's only applicable to cross-OS compilation. Always leave anything for the
// host OS alone though.
if os == "macos" {
let mut env_remove = Vec::with_capacity(2);
// Remove the `SDKROOT` environment variable if it's clearly set for the wrong platform, which
// may occur when we're linking a custom build script while targeting iOS for example.
if let Ok(sdkroot) = env::var("SDKROOT") {
if sdkroot.contains("iPhoneOS.platform")
|| sdkroot.contains("iPhoneSimulator.platform")
|| sdkroot.contains("AppleTVOS.platform")
|| sdkroot.contains("AppleTVSimulator.platform")
|| sdkroot.contains("WatchOS.platform")
|| sdkroot.contains("WatchSimulator.platform")
|| sdkroot.contains("XROS.platform")
|| sdkroot.contains("XRSimulator.platform")
{
env_remove.push("SDKROOT".into())
}
}
// Additionally, `IPHONEOS_DEPLOYMENT_TARGET` must not be set when using the Xcode linker at
// "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld",
// although this is apparently ignored when using the linker at "/usr/bin/ld".
env_remove.push("IPHONEOS_DEPLOYMENT_TARGET".into());
env_remove.push("TVOS_DEPLOYMENT_TARGET".into());
env_remove.push("XROS_DEPLOYMENT_TARGET".into());
env_remove.into()
} else {
// Otherwise if cross-compiling for a different OS/SDK (including Mac Catalyst), remove any part
// of the linking environment that's wrong and reversed.
cvs!["MACOSX_DEPLOYMENT_TARGET"]
}
}
/// Parse an OS version triple (SDK version or deployment target).
///
/// The size of the returned numbers here are limited by Mach-O's
/// `LC_BUILD_VERSION`.
fn parse_version(version: &str) -> Result<(u16, u8, u8), ParseIntError> {
if let Some((major, minor)) = version.split_once('.') {
let major = major.parse()?;
if let Some((minor, patch)) = minor.split_once('.') {
Ok((major, minor.parse()?, patch.parse()?))
} else {
Ok((major, minor.parse()?, 0))
}
} else {
Ok((version.parse()?, 0, 0))
}
}