Rollup merge of #100286 - Thog:rust-lld-macosx-target, r=petrochenkov

Add support for link-flavor rust-lld for macOS

Also refactor iOS, watchOS and tvOS common code.

The ``-arch`` argument was moved to the ``apple_base`` module instead of the target definitions for macOS.
As ld64 requires ``-syslibroot`` to be passed, ``add_apple_sdk`` was modified accordingly.

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2674,11 +2674,16 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
     let os = &sess.target.os;
     let llvm_target = &sess.target.llvm_target;
     if sess.target.vendor != "apple"
-        || !matches!(os.as_ref(), "ios" | "tvos" | "watchos")
+        || !matches!(os.as_ref(), "ios" | "tvos" | "watchos" | "macos")
         || (flavor != LinkerFlavor::Gcc && flavor != LinkerFlavor::Lld(LldFlavor::Ld64))
     {
         return;
     }
+
+    if os == "macos" && flavor != LinkerFlavor::Lld(LldFlavor::Ld64) {
+        return;
+    }
+
     let sdk_name = match (arch.as_ref(), os.as_ref()) {
         ("aarch64", "tvos") => "appletvos",
         ("x86_64", "tvos") => "appletvsimulator",
@@ -2694,6 +2699,7 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         ("aarch64", "watchos") if llvm_target.ends_with("-simulator") => "watchsimulator",
         ("aarch64", "watchos") => "watchos",
         ("arm", "watchos") => "watchos",
+        (_, "macos") => "macosx",
         _ => {
             sess.err(&format!("unsupported arch `{}` for os `{}`", arch, os));
             return;

compiler/rustc_target/src/spec/aarch64_apple_darwin.rs

@@ -1,20 +1,20 @@
-use crate::spec::{FramePointer, LinkerFlavor, SanitizerSet, Target, TargetOptions};
+use crate::spec::{FramePointer, SanitizerSet, Target, TargetOptions};
 
 pub fn target() -> Target {
-    let mut base = super::apple_base::opts("macos");
+    let arch = "arm64";
+    let mut base = super::apple_base::opts("macos", arch, "");
     base.cpu = "apple-a14".into();
     base.max_atomic_width = Some(128);
 
     // FIXME: The leak sanitizer currently fails the tests, see #88132.
     base.supported_sanitizers = SanitizerSet::ADDRESS | SanitizerSet::CFI | SanitizerSet::THREAD;
 
-    base.add_pre_link_args(LinkerFlavor::Gcc, &["-arch", "arm64"]);
     base.link_env_remove.to_mut().extend(super::apple_base::macos_link_env_remove());
 
     // Clang automatically chooses a more specific target based on
     // MACOSX_DEPLOYMENT_TARGET.  To enable cross-language LTO to work
     // correctly, we do too.
-    let llvm_target = super::apple_base::macos_llvm_target("arm64");
+    let llvm_target = super::apple_base::macos_llvm_target(arch);
 
     Target {
         llvm_target: llvm_target.into(),

compiler/rustc_target/src/spec/apple_base.rs

@@ -1,8 +1,45 @@
 use std::{borrow::Cow, env};
 
-use crate::spec::{cvs, FramePointer, LldFlavor, SplitDebuginfo, TargetOptions};
+use crate::spec::{cvs, FramePointer, SplitDebuginfo, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor};
 
-pub fn opts(os: &'static str) -> TargetOptions {
+fn pre_link_args(os: &'static str, arch: &'static str, abi: &'static str) -> LinkArgs {
+    let mut args = LinkArgs::new();
+
+    let platform_name = match abi {
+        "sim" => format!("{}-simulator", os),
+        "macabi" => "mac-catalyst".to_string(),
+        _ => os.to_string(),
+    };
+
+    let platform_version = match os.as_ref() {
+        "ios" => ios_lld_platform_version(),
+        "tvos" => tvos_lld_platform_version(),
+        "watchos" => watchos_lld_platform_version(),
+        "macos" => macos_lld_platform_version(arch),
+        _ => unreachable!(),
+    };
+
+    if abi != "macabi" {
+        args.insert(LinkerFlavor::Gcc, vec!["-arch".into(), arch.into()]);
+    }
+
+    args.insert(
+        LinkerFlavor::Lld(LldFlavor::Ld64),
+        vec![
+            "-arch".into(),
+            arch.into(),
+            "-platform_version".into(),
+            platform_name.into(),
+            platform_version.clone().into(),
+            platform_version.into(),
+        ],
+    );
+
+    args
+}
+
+pub fn opts(os: &'static str, arch: &'static str, abi: &'static str) -> TargetOptions {
     // ELF TLS is only available in macOS 10.7+. If you try to compile for 10.6
     // either the linker will complain if it is used or the binary will end up
     // segfaulting at runtime when run on 10.6. Rust by default supports macOS
@@ -24,6 +61,7 @@ pub fn opts(os: &'static str) -> TargetOptions {
         // 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),
         linker_is_gnu: false,
         families: cvs!["unix"],
         is_like_osx: true,
@@ -73,6 +111,11 @@ fn macos_deployment_target(arch: &str) -> (u32, u32) {
         .unwrap_or_else(|| macos_default_deployment_target(arch))
 }
 
+fn macos_lld_platform_version(arch: &str) -> String {
+    let (major, minor) = macos_deployment_target(arch);
+    format!("{}.{}", major, minor)
+}
+
 pub fn macos_llvm_target(arch: &str) -> String {
     let (major, minor) = macos_deployment_target(arch);
     format!("{}-apple-macosx{}.{}.0", arch, major, minor)
@@ -109,7 +152,7 @@ pub fn ios_llvm_target(arch: &str) -> String {
     format!("{}-apple-ios{}.{}.0", arch, major, minor)
 }
 
-pub fn ios_lld_platform_version() -> String {
+fn ios_lld_platform_version() -> String {
     let (major, minor) = ios_deployment_target();
     format!("{}.{}", major, minor)
 }
@@ -123,7 +166,7 @@ fn tvos_deployment_target() -> (u32, u32) {
     deployment_target("TVOS_DEPLOYMENT_TARGET").unwrap_or((7, 0))
 }
 
-pub fn tvos_lld_platform_version() -> String {
+fn tvos_lld_platform_version() -> String {
     let (major, minor) = tvos_deployment_target();
     format!("{}.{}", major, minor)
 }
@@ -132,7 +175,7 @@ fn watchos_deployment_target() -> (u32, u32) {
     deployment_target("WATCHOS_DEPLOYMENT_TARGET").unwrap_or((5, 0))
 }
 
-pub fn watchos_lld_platform_version() -> String {
+fn watchos_lld_platform_version() -> String {
     let (major, minor) = watchos_deployment_target();
     format!("{}.{}", major, minor)
 }

compiler/rustc_target/src/spec/apple_sdk_base.rs

@@ -1,4 +1,4 @@
-use crate::spec::{cvs, LinkArgs, LinkerFlavor, LldFlavor, TargetOptions};
+use crate::spec::{cvs, TargetOptions};
 use std::borrow::Cow;
 
 use Arch::*;
@@ -61,53 +61,13 @@ fn link_env_remove(arch: Arch) -> Cow<'static, [Cow<'static, str>]> {
     }
 }
 
-fn pre_link_args(os: &'static str, arch: Arch) -> LinkArgs {
-    let mut args = LinkArgs::new();
-
-    let target_abi = target_abi(arch);
-
-    let platform_name = match target_abi {
-        "sim" => format!("{}-simulator", os),
-        "macabi" => "mac-catalyst".to_string(),
-        _ => os.to_string(),
-    };
-
-    let platform_version = match os.as_ref() {
-        "ios" => super::apple_base::ios_lld_platform_version(),
-        "tvos" => super::apple_base::tvos_lld_platform_version(),
-        "watchos" => super::apple_base::watchos_lld_platform_version(),
-        _ => unreachable!(),
-    };
-
-    let arch_str = target_arch_name(arch);
-
-    if target_abi != "macabi" {
-        args.insert(LinkerFlavor::Gcc, vec!["-arch".into(), arch_str.into()]);
-    }
-
-    args.insert(
-        LinkerFlavor::Lld(LldFlavor::Ld64),
-        vec![
-            "-arch".into(),
-            arch_str.into(),
-            "-platform_version".into(),
-            platform_name.into(),
-            platform_version.clone().into(),
-            platform_version.into(),
-        ],
-    );
-
-    args
-}
-
 pub fn opts(os: &'static str, arch: Arch) -> TargetOptions {
     TargetOptions {
         abi: target_abi(arch).into(),
         cpu: target_cpu(arch).into(),
         dynamic_linking: false,
-        pre_link_args: pre_link_args(os, arch),
         link_env_remove: link_env_remove(arch),
         has_thread_local: false,
-        ..super::apple_base::opts(os)
+        ..super::apple_base::opts(os, target_arch_name(arch), target_abi(arch))
     }
 }

compiler/rustc_target/src/spec/i686_apple_darwin.rs

@@ -1,7 +1,8 @@
 use crate::spec::{FramePointer, LinkerFlavor, StackProbeType, Target, TargetOptions};
 
 pub fn target() -> Target {
-    let mut base = super::apple_base::opts("macos");
+    // ld64 only understand i386 and not i686
+    let mut base = super::apple_base::opts("macos", "i386", "");
     base.cpu = "yonah".into();
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gcc, &["-m32"]);

compiler/rustc_target/src/spec/x86_64_apple_darwin.rs

@@ -2,11 +2,12 @@ use crate::spec::TargetOptions;
 use crate::spec::{FramePointer, LinkerFlavor, SanitizerSet, StackProbeType, Target};
 
 pub fn target() -> Target {
-    let mut base = super::apple_base::opts("macos");
+    let arch = "x86_64";
+    let mut base = super::apple_base::opts("macos", arch, "");
     base.cpu = "core2".into();
     base.max_atomic_width = Some(128); // core2 support cmpxchg16b
     base.frame_pointer = FramePointer::Always;
-    base.add_pre_link_args(LinkerFlavor::Gcc, &["-m64", "-arch", "x86_64"]);
+    base.add_pre_link_args(LinkerFlavor::Gcc, &["-m64"]);
     base.link_env_remove.to_mut().extend(super::apple_base::macos_link_env_remove());
     // don't use probe-stack=inline-asm until rust#83139 and rust#84667 are resolved
     base.stack_probes = StackProbeType::Call;
@@ -16,7 +17,6 @@ pub fn target() -> Target {
     // Clang automatically chooses a more specific target based on
     // MACOSX_DEPLOYMENT_TARGET.  To enable cross-language LTO to work
     // correctly, we do too.
-    let arch = "x86_64";
     let llvm_target = super::apple_base::macos_llvm_target(&arch);
 
     Target {