tvOS simulator support on Apple Silicon for rustc

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2871,6 +2871,7 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
     }
 
     let sdk_name = match (arch.as_ref(), os.as_ref()) {
+        ("aarch64", "tvos") if llvm_target.ends_with("-simulator") => "appletvsimulator",
         ("aarch64", "tvos") => "appletvos",
         ("x86_64", "tvos") => "appletvsimulator",
         ("arm", "ios") => "iphoneos",

compiler/rustc_target/src/spec/aarch64_apple_tvos_sim.rs

@@ -0,0 +1,31 @@
+use super::apple_base::{opts, tvos_sim_llvm_target, Arch};
+use crate::spec::{FramePointer, Target, TargetOptions};
+
+pub fn target() -> Target {
+    let arch = Arch::Arm64_sim;
+    Target {
+        llvm_target: tvos_sim_llvm_target(arch).into(),
+        pointer_width: 64,
+        data_layout: "e-m:o-i64:64-i128:128-n32:64-S128".into(),
+        arch: arch.target_arch(),
+        options: TargetOptions {
+            features: "+neon,+fp-armv8,+apple-a7".into(),
+            max_atomic_width: Some(128),
+            forces_embed_bitcode: true,
+            frame_pointer: FramePointer::NonLeaf,
+            // Taken from (and slightly modified) the aarch64-apple-ios-sim spec which says:
+            // Taken from a clang build on Xcode 11.4.1.
+            // These arguments are not actually invoked - they just have
+            // to look right to pass App Store validation.
+            bitcode_llvm_cmdline: "-triple\0\
+                arm64-apple-tvos15.0-simulator\0\
+                -emit-obj\0\
+                -disable-llvm-passes\0\
+                -target-abi\0\
+                darwinpcs\0\
+                -Os\0"
+                .into(),
+            ..opts("tvos", arch)
+        },
+    }
+}

compiler/rustc_target/src/spec/mod.rs

@@ -1399,6 +1399,7 @@ supported_targets! {
     ("aarch64-apple-ios-macabi", aarch64_apple_ios_macabi),
     ("aarch64-apple-ios-sim", aarch64_apple_ios_sim),
     ("aarch64-apple-tvos", aarch64_apple_tvos),
+    ("aarch64-apple-tvos-sim", aarch64_apple_tvos_sim),
     ("x86_64-apple-tvos", x86_64_apple_tvos),
 
     ("armv7k-apple-watchos", armv7k_apple_watchos),

src/doc/rustc/src/platform-support.md

@@ -225,6 +225,7 @@ target | std | host | notes
 -------|:---:|:----:|-------
 `aarch64-apple-ios-macabi` | ? |  | Apple Catalyst on ARM64
 [`aarch64-apple-tvos`](platform-support/apple-tvos.md) | ? |  | ARM64 tvOS
+[`aarch64-apple-tvos-sim`](platform-support/apple-tvos.md) | ? |  | ARM64 tvOS Simulator
 [`aarch64-apple-watchos-sim`](platform-support/apple-watchos.md) | ✓ |  | ARM64 Apple WatchOS Simulator
 [`aarch64-kmc-solid_asp3`](platform-support/kmc-solid.md) | ✓ |  | ARM64 SOLID with TOPPERS/ASP3
 [`aarch64-nintendo-switch-freestanding`](platform-support/aarch64-nintendo-switch-freestanding.md) | * |  | ARM64 Nintendo Switch, Horizon

src/doc/rustc/src/platform-support/apple-tvos.md

@@ -52,7 +52,7 @@ The targets can be built by enabling them for a `rustc` build in `config.toml`,
 ```toml
 [build]
 build-stage = 1
-target = ["aarch64-apple-tvos", "x86_64-apple-tvos"]
+target = ["aarch64-apple-tvos", "x86_64-apple-tvos", "aarch64-apple-tvos-sim"]
 ```
 
 It's possible that cargo under `-Zbuild-std` may also be used to target them.
@@ -67,6 +67,8 @@ Rust programs can be built for these targets
 $ rustc --target aarch64-apple-tvos your-code.rs
 ...
 $ rustc --target x86_64-apple-tvos your-code.rs
+...
+$ rustc --target aarch64-apple-tvos-sim your-code.rs
 ```
 
 ## Testing