Link with default MACOSX_DEPLOYMENT_TARGET if not otherwise specified.

compiler/rustc_target/src/spec/aarch64_apple_darwin.rs

@@ -9,19 +9,19 @@ pub fn target() -> Target {
     base.supported_sanitizers = SanitizerSet::ADDRESS | SanitizerSet::CFI | SanitizerSet::THREAD;
 
     base.pre_link_args.insert(LinkerFlavor::Gcc, vec!["-arch".to_string(), "arm64".to_string()]);
+    base.link_env.extend(super::apple_base::macos_link_env("arm64"));
     base.link_env_remove.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 arch = "aarch64";
-    let llvm_target = super::apple_base::macos_llvm_target(&arch);
+    let llvm_target = super::apple_base::macos_llvm_target("arm64");
 
     Target {
         llvm_target,
         pointer_width: 64,
         data_layout: "e-m:o-i64:64-i128:128-n32:64-S128".to_string(),
-        arch: arch.to_string(),
+        arch: "aarch64".to_string(),
         options: TargetOptions {
             mcount: "\u{1}mcount".to_string(),
             frame_pointer: FramePointer::NonLeaf,

compiler/rustc_target/src/spec/apple_base.rs

@@ -13,8 +13,10 @@ pub fn opts(os: &str) -> TargetOptions {
     // warnings about the usage of ELF TLS.
     //
     // Here we detect what version is being requested, defaulting to 10.7. ELF
-    // TLS is flagged as enabled if it looks to be supported.
-    let version = macos_deployment_target();
+    // TLS is flagged as enabled if it looks to be supported. The architecture
+    // only matters for default deployment target which is 11.0 for ARM64 and
+    // 10.7 for everything else.
+    let has_elf_tls = macos_deployment_target("x86_64") >= (10, 7);
 
     TargetOptions {
         os: os.to_string(),
@@ -31,7 +33,7 @@ pub fn opts(os: &str) -> TargetOptions {
         has_rpath: true,
         dll_suffix: ".dylib".to_string(),
         archive_format: "darwin".to_string(),
-        has_elf_tls: version >= (10, 7),
+        has_elf_tls,
         abi_return_struct_as_int: true,
         emit_debug_gdb_scripts: false,
         eh_frame_header: false,
@@ -63,15 +65,32 @@ fn deployment_target(var_name: &str) -> Option<(u32, u32)> {
         .and_then(|(a, b)| a.parse::<u32>().and_then(|a| b.parse::<u32>().map(|b| (a, b))).ok())
 }
 
-fn macos_deployment_target() -> (u32, u32) {
-    deployment_target("MACOSX_DEPLOYMENT_TARGET").unwrap_or((10, 7))
+fn macos_default_deployment_target(arch: &str) -> (u32, u32) {
+    if arch == "arm64" { (11, 0) } else { (10, 7) }
+}
+
+fn macos_deployment_target(arch: &str) -> (u32, u32) {
+    deployment_target("MACOSX_DEPLOYMENT_TARGET")
+        .unwrap_or_else(|| macos_default_deployment_target(arch))
 }
 
 pub fn macos_llvm_target(arch: &str) -> String {
-    let (major, minor) = macos_deployment_target();
+    let (major, minor) = macos_deployment_target(arch);
     format!("{}-apple-macosx{}.{}.0", arch, major, minor)
 }
 
+pub fn macos_link_env(arch: &str) -> Vec<(String, String)> {
+    // Use the default deployment target for linking just as with the LLVM target if not
+    // specified via MACOSX_DEPLOYMENT_TARGET, otherwise the system linker would use its
+    // default which varies with Xcode version.
+    if env::var("MACOSX_DEPLOYMENT_TARGET").is_err() {
+        let default = macos_default_deployment_target(arch);
+        vec![("MACOSX_DEPLOYMENT_TARGET".to_string(), format!("{}.{}", default.0, default.1))]
+    } else {
+        vec![]
+    }
+}
+
 pub fn macos_link_env_remove() -> Vec<String> {
     let mut env_remove = Vec::with_capacity(2);
     // Remove the `SDKROOT` environment variable if it's clearly set for the wrong platform, which

compiler/rustc_target/src/spec/i686_apple_darwin.rs

@@ -5,6 +5,7 @@ pub fn target() -> Target {
     base.cpu = "yonah".to_string();
     base.max_atomic_width = Some(64);
     base.pre_link_args.insert(LinkerFlavor::Gcc, vec!["-m32".to_string()]);
+    base.link_env.extend(super::apple_base::macos_link_env("i686"));
     base.link_env_remove.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;

compiler/rustc_target/src/spec/x86_64_apple_darwin.rs

@@ -10,6 +10,7 @@ pub fn target() -> Target {
         LinkerFlavor::Gcc,
         vec!["-m64".to_string(), "-arch".to_string(), "x86_64".to_string()],
     );
+    base.link_env.extend(super::apple_base::macos_link_env("x86_64"));
     base.link_env_remove.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;