From c3457cf8bb2d4c1e5c9dc1a0974ae98e803bd487 Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Wed, 16 Jun 2021 15:03:51 +0100
Subject: [PATCH 01/10] [watchos] add target specs for watchos armv7k and
 arm64_32

[watchos] Add spec for x86_64-apple-watchos-sim
---
 compiler/rustc_codegen_llvm/src/back/write.rs |  3 +-
 compiler/rustc_target/src/spec/apple_base.rs  |  9 +++++
 .../rustc_target/src/spec/apple_sdk_base.rs   |  6 +++-
 .../src/spec/arm64_32_apple_watchos.rs        | 29 ++++++++++++++++
 .../src/spec/armv7k_apple_watchos.rs          | 18 ++++++++++
 compiler/rustc_target/src/spec/mod.rs         |  4 +++
 .../src/spec/x86_64_apple_watchos_sim.rs      | 34 +++++++++++++++++++
 library/panic_unwind/src/dwarf/eh.rs          |  3 +-
 library/panic_unwind/src/gcc.rs               |  2 +-
 library/std/build.rs                          |  1 +
 library/unwind/src/libunwind.rs               |  8 ++---
 11 files changed, 109 insertions(+), 8 deletions(-)
 create mode 100644 compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs
 create mode 100644 compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
 create mode 100644 compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs

diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index c18719d4ad739..e7d6bbb30273b 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -1035,7 +1035,8 @@ unsafe fn embed_bitcode(
     // reason (see issue #90326 for historical background).
     let is_apple = cgcx.opts.target_triple.triple().contains("-ios")
         || cgcx.opts.target_triple.triple().contains("-darwin")
-        || cgcx.opts.target_triple.triple().contains("-tvos");
+        || cgcx.opts.target_triple.triple().contains("-tvos")
+        || cgcx.opts.target_triple.triple().contains("-watchos");
     if is_apple
         || cgcx.opts.target_triple.triple().starts_with("wasm")
         || cgcx.opts.target_triple.triple().starts_with("asmjs")
diff --git a/compiler/rustc_target/src/spec/apple_base.rs b/compiler/rustc_target/src/spec/apple_base.rs
index a4488f695f210..8ca5284eb2a0e 100644
--- a/compiler/rustc_target/src/spec/apple_base.rs
+++ b/compiler/rustc_target/src/spec/apple_base.rs
@@ -114,3 +114,12 @@ pub fn ios_sim_llvm_target(arch: &str) -> String {
     let (major, minor) = ios_deployment_target();
     format!("{}-apple-ios{}.{}.0-simulator", arch, major, minor)
 }
+
+fn watchos_deployment_target() -> (u32, u32) {
+    deployment_target("WATCHOS_DEPLOYMENT_TARGET").unwrap_or((5, 0))
+}
+
+pub fn watchos_sim_llvm_target(arch: &str) -> String {
+    let (major, minor) = watchos_deployment_target();
+    format!("{}-apple-watchos{}.{}.0-simulator", arch, major, minor)
+}
diff --git a/compiler/rustc_target/src/spec/apple_sdk_base.rs b/compiler/rustc_target/src/spec/apple_sdk_base.rs
index 874e9b56aaa1e..0bcccf1df2d93 100644
--- a/compiler/rustc_target/src/spec/apple_sdk_base.rs
+++ b/compiler/rustc_target/src/spec/apple_sdk_base.rs
@@ -5,8 +5,10 @@ use Arch::*;
 #[derive(Copy, Clone)]
 pub enum Arch {
     Armv7,
+    Armv7k,
     Armv7s,
     Arm64,
+    Arm64_32,
     I386,
     X86_64,
     X86_64_macabi,
@@ -26,8 +28,10 @@ fn target_abi(arch: Arch) -> String {
 fn target_cpu(arch: Arch) -> String {
     match arch {
         Armv7 => "cortex-a8", // iOS7 is supported on iPhone 4 and higher
+        Armv7k => "cortex-a8",
         Armv7s => "cortex-a9",
         Arm64 => "apple-a7",
+        Arm64_32 => "apple-s4",
         I386 => "yonah",
         X86_64 => "core2",
         X86_64_macabi => "core2",
@@ -39,7 +43,7 @@ fn target_cpu(arch: Arch) -> String {
 
 fn link_env_remove(arch: Arch) -> Vec<String> {
     match arch {
-        Armv7 | Armv7s | Arm64 | I386 | X86_64 | Arm64_sim => {
+        Armv7 | Armv7k | Armv7s | Arm64 | Arm64_32 | I386 | X86_64 | Arm64_sim => {
             vec!["MACOSX_DEPLOYMENT_TARGET".to_string()]
         }
         X86_64_macabi | Arm64_macabi => vec!["IPHONEOS_DEPLOYMENT_TARGET".to_string()],
diff --git a/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs b/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs
new file mode 100644
index 0000000000000..504bcd63052c7
--- /dev/null
+++ b/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs
@@ -0,0 +1,29 @@
+use super::apple_sdk_base::{opts, Arch};
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    let base = opts("watchos", Arch::Arm64_32);
+    Target {
+        llvm_target: "arm64_32-apple-watchos".to_string(),
+        pointer_width: 32,
+        data_layout: "e-m:o-p:32:32-i64:64-i128:128-n32:64-S128".to_string(),
+        arch: "aarch64".to_string(),
+        options: TargetOptions {
+            features: "+neon,+fp-armv8,+apple-a7".to_string(),
+            max_atomic_width: Some(64),
+            unsupported_abis: super::arm_base::unsupported_abis(),
+            forces_embed_bitcode: true,
+            // These arguments are not actually invoked - they just have
+            // to look right to pass App Store validation.
+            bitcode_llvm_cmdline: "-triple\0\
+                arm64_32-apple-watchos5.0.0\0\
+                -emit-obj\0\
+                -disable-llvm-passes\0\
+                -target-abi\0\
+                darwinpcs\0\
+                -Os\0"
+                .to_string(),
+            ..base
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
new file mode 100644
index 0000000000000..14092b9949457
--- /dev/null
+++ b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
@@ -0,0 +1,18 @@
+use super::apple_sdk_base::{opts, Arch};
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    let base = opts("watchos", Arch::Armv7k);
+    Target {
+        llvm_target: "armv7k-apple-watchos".to_string(),
+        pointer_width: 32,
+        data_layout: "e-m:o-p:32:32-Fi8-i64:64-a:0:32-n32-S128".to_string(),
+        arch: "arm".to_string(),
+        options: TargetOptions {
+            features: "+v7".to_string(),
+            max_atomic_width: Some(64),
+            unsupported_abis: super::arm_base::unsupported_abis(),
+            ..base
+        },
+    }
+}
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 4f0c3bec1eecc..a07d61686b6e9 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -923,6 +923,10 @@ supported_targets! {
     ("aarch64-apple-tvos", aarch64_apple_tvos),
     ("x86_64-apple-tvos", x86_64_apple_tvos),
 
+    ("armv7k-apple-watchos", armv7k_apple_watchos),
+    ("arm64_32-apple-watchos", arm64_32_apple_watchos),
+    ("x86_64-apple-watchos-sim", x86_64_apple_watchos_sim),
+
     ("armebv7r-none-eabi", armebv7r_none_eabi),
     ("armebv7r-none-eabihf", armebv7r_none_eabihf),
     ("armv7r-none-eabi", armv7r_none_eabi),
diff --git a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
new file mode 100644
index 0000000000000..638f36a8bcba1
--- /dev/null
+++ b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
@@ -0,0 +1,34 @@
+use super::apple_sdk_base::{opts, Arch};
+use crate::spec::{StackProbeType, Target, TargetOptions};
+
+pub fn target() -> Target {
+    let base = opts("watchos", Arch::X86_64);
+
+    let arch = "x86_64";
+    let llvm_target = super::apple_base::watchos_sim_llvm_target(arch);
+
+    Target {
+        llvm_target: llvm_target,
+        pointer_width: 64,
+        data_layout: "e-m:o-i64:64-f80:128-n8:16:32:64-S128".to_string(),
+        arch: "x86_64".to_string(),
+        options: TargetOptions {
+            max_atomic_width: Some(64),
+            // don't use probe-stack=inline-asm until rust#83139 and rust#84667 are resolved
+            stack_probes: StackProbeType::Call,
+            forces_embed_bitcode: true,
+            // 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\
+                x86_64-apple-watchos5.0-simulator\0\
+                -emit-obj\0\
+                -disable-llvm-passes\0\
+                -target-abi\0\
+                darwinpcs\0\
+                -Os\0"
+                .to_string(),
+            ..base
+        },
+    }
+}
diff --git a/library/panic_unwind/src/dwarf/eh.rs b/library/panic_unwind/src/dwarf/eh.rs
index 7394feab82f22..44086cd141e59 100644
--- a/library/panic_unwind/src/dwarf/eh.rs
+++ b/library/panic_unwind/src/dwarf/eh.rs
@@ -49,7 +49,8 @@ pub enum EHAction {
     Terminate,
 }
 
-pub const USING_SJLJ_EXCEPTIONS: bool = cfg!(all(target_os = "ios", target_arch = "arm"));
+pub const USING_SJLJ_EXCEPTIONS: bool =
+    cfg!(all(any(target_os = "ios", target_os = "watchos"), target_arch = "arm"));
 
 pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>) -> Result<EHAction, ()> {
     if lsda.is_null() {
diff --git a/library/panic_unwind/src/gcc.rs b/library/panic_unwind/src/gcc.rs
index a0297b4b2f524..057e47bfdd18a 100644
--- a/library/panic_unwind/src/gcc.rs
+++ b/library/panic_unwind/src/gcc.rs
@@ -131,7 +131,7 @@ const UNWIND_DATA_REG: (i32, i32) = (10, 11); // x10, x11
 // https://github.com/gcc-mirror/gcc/blob/trunk/libgcc/unwind-c.c
 
 cfg_if::cfg_if! {
-    if #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(target_os = "netbsd")))] {
+    if #[cfg(all(target_arch = "arm", not(target_os = "ios"), not(target_os = "watchos"), not(target_os = "netbsd")))] {
         // ARM EHABI personality routine.
         // https://infocenter.arm.com/help/topic/com.arm.doc.ihi0038b/IHI0038B_ehabi.pdf
         //
diff --git a/library/std/build.rs b/library/std/build.rs
index 43168e77296ab..a6fdf500b63ca 100644
--- a/library/std/build.rs
+++ b/library/std/build.rs
@@ -15,6 +15,7 @@ fn main() {
         || target.contains("illumos")
         || target.contains("apple-darwin")
         || target.contains("apple-ios")
+        || target.contains("apple-watchos")
         || target.contains("uwp")
         || target.contains("windows")
         || target.contains("fuchsia")
diff --git a/library/unwind/src/libunwind.rs b/library/unwind/src/libunwind.rs
index 432628613f586..380d8ec6838e0 100644
--- a/library/unwind/src/libunwind.rs
+++ b/library/unwind/src/libunwind.rs
@@ -30,10 +30,10 @@ pub const unwinder_private_data_size: usize = 5;
 #[cfg(target_arch = "x86_64")]
 pub const unwinder_private_data_size: usize = 6;
 
-#[cfg(all(target_arch = "arm", not(target_os = "ios")))]
+#[cfg(all(target_arch = "arm", not(any(target_os = "ios", target_os = "watchos"))))]
 pub const unwinder_private_data_size: usize = 20;
 
-#[cfg(all(target_arch = "arm", target_os = "ios"))]
+#[cfg(all(target_arch = "arm", any(target_os = "ios", target_os = "watchos")))]
 pub const unwinder_private_data_size: usize = 5;
 
 #[cfg(all(target_arch = "aarch64", target_pointer_width = "64"))]
@@ -105,7 +105,7 @@ extern "C" {
 }
 
 cfg_if::cfg_if! {
-if #[cfg(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm")))] {
+if #[cfg(any(target_os = "ios", target_os = "watchos", target_os = "netbsd", not(target_arch = "arm")))] {
     // Not ARM EHABI
     #[repr(C)]
     #[derive(Copy, Clone, PartialEq)]
@@ -240,7 +240,7 @@ if #[cfg(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm")))
 } // cfg_if!
 
 cfg_if::cfg_if! {
-if #[cfg(not(all(target_os = "ios", target_arch = "arm")))] {
+if #[cfg(not(all(any(target_os = "ios", target_os = "watchos"), target_arch = "arm")))] {
     // Not 32-bit iOS
     #[cfg_attr(
         all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),

From 08a7e59b3ddf1e96b28c4625ae48cb6988877554 Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Thu, 17 Jun 2021 09:31:50 +0100
Subject: [PATCH 02/10] [watch_os] add stdlib (match ios)

[watch_os] misc fixes

[watch_os] fix target builds
---
 Cargo.toml                                    |   2 +
 compiler/rustc_codegen_ssa/src/back/link.rs   |  13 +-
 .../src/spec/armv7k_apple_watchos.rs          |   2 +-
 library/panic_abort/Cargo.toml                |   4 +-
 library/std/src/os/mod.rs                     |   2 +
 library/std/src/os/unix/mod.rs                |   3 +
 library/std/src/os/unix/net/stream.rs         |   3 +
 library/std/src/os/unix/ucred.rs              |   4 +-
 library/std/src/os/unix/ucred/tests.rs        |   3 +-
 library/std/src/os/watchos/fs.rs              | 142 ++++++++++++++++++
 library/std/src/os/watchos/mod.rs             |   6 +
 library/std/src/os/watchos/raw.rs             |  83 ++++++++++
 library/std/src/sys/unix/args.rs              |   4 +-
 library/std/src/sys/unix/env.rs               |  11 ++
 library/std/src/sys/unix/fd.rs                |   2 +
 library/std/src/sys/unix/fs.rs                |  20 ++-
 .../std/src/sys/unix/locks/pthread_condvar.rs |   6 +
 library/std/src/sys/unix/mod.rs               |   5 +-
 library/std/src/sys/unix/os.rs                |   6 +-
 library/std/src/sys/unix/rand.rs              |   3 +-
 library/std/src/sys/unix/thread.rs            |   2 +-
 library/std/src/sys/unix/time.rs              |   4 +-
 library/std/src/sys_common/net.rs             |   2 +-
 src/bootstrap/native.rs                       |   5 +-
 src/tools/compiletest/src/raise_fd_limit.rs   |   2 +-
 src/tools/compiletest/src/util.rs             |   1 +
 26 files changed, 312 insertions(+), 28 deletions(-)
 create mode 100644 library/std/src/os/watchos/fs.rs
 create mode 100644 library/std/src/os/watchos/mod.rs
 create mode 100644 library/std/src/os/watchos/raw.rs

diff --git a/Cargo.toml b/Cargo.toml
index 4e78399606445..0ec3f510ea81f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -125,6 +125,8 @@ rustfmt-nightly = { path = "src/tools/rustfmt" }
 # See comments in `src/tools/rustc-workspace-hack/README.md` for what's going on
 # here
 rustc-workspace-hack = { path = 'src/tools/rustc-workspace-hack' }
+cc = { git = "https://github.com/vladimir-ea/cc-rs", branch = "watch_os" }
+libc = { git = "https://github.com/vladimir-ea/libc", branch = "watch_os" }
 
 # See comments in `library/rustc-std-workspace-core/README.md` for what's going on
 # here
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 9cc06ac031969..5d188e304dc38 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -2457,7 +2457,7 @@ 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_str(), "ios" | "tvos")
+        || !matches!(os.as_str(), "ios" | "tvos" | "watchos")
         || flavor != LinkerFlavor::Gcc
     {
         return;
@@ -2472,6 +2472,10 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         ("x86", "ios") => "iphonesimulator",
         ("x86_64", "ios") if llvm_target.contains("macabi") => "macosx",
         ("x86_64", "ios") => "iphonesimulator",
+        ("x86_64", "watchos") => "watchsimulator",
+        ("arm64_32", "watchos") => "watchos",
+        ("aarch64", "watchos") => "watchos",
+        ("armv7k", "watchos") => "watchos",
         _ => {
             sess.err(&format!("unsupported arch `{}` for os `{}`", arch, os));
             return;
@@ -2518,13 +2522,18 @@ fn get_apple_sdk_root(sdk_name: &str) -> Result<String, String> {
             "macosx10.15"
                 if sdkroot.contains("iPhoneOS.platform")
                     || sdkroot.contains("iPhoneSimulator.platform") => {}
+            "watchos"
+                if sdkroot.contains("WatchSimulator.platform")
+                    || sdkroot.contains("MacOSX.platform") => {}
+            "watchsimulator"
+                if sdkroot.contains("WatchOS.platform") || sdkroot.contains("MacOSX.platform") => {}
             // Ignore `SDKROOT` if it's not a valid path.
             _ if !p.is_absolute() || p == Path::new("/") || !p.exists() => {}
             _ => return Ok(sdkroot),
         }
     }
     let res =
-        Command::new("xcrun").arg("--show-sdk-path").arg("-sdk").arg(sdk_name).output().and_then(
+        Command::new("xcrunp").arg("--show-sdk-path").arg("-sdk").arg(sdk_name).output().and_then(
             |output| {
                 if output.status.success() {
                     Ok(String::from_utf8(output.stdout).unwrap())
diff --git a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
index 14092b9949457..5fe07264d095b 100644
--- a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
+++ b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
@@ -9,7 +9,7 @@ pub fn target() -> Target {
         data_layout: "e-m:o-p:32:32-Fi8-i64:64-a:0:32-n32-S128".to_string(),
         arch: "arm".to_string(),
         options: TargetOptions {
-            features: "+v7".to_string(),
+            features: "+v7,+vfp4,+neon".to_string(),
             max_atomic_width: Some(64),
             unsupported_abis: super::arm_base::unsupported_abis(),
             ..base
diff --git a/library/panic_abort/Cargo.toml b/library/panic_abort/Cargo.toml
index 46183d1ad0066..ea1c36d16be96 100644
--- a/library/panic_abort/Cargo.toml
+++ b/library/panic_abort/Cargo.toml
@@ -15,5 +15,5 @@ doc = false
 alloc = { path = "../alloc" }
 cfg-if = { version = "0.1.8", features = ['rustc-dep-of-std'] }
 core = { path = "../core" }
-libc = { version = "0.2", default-features = false }
-compiler_builtins = "0.1.0"
+libc = { version = "*", default-features = false }
+compiler_builtins = "*"
diff --git a/library/std/src/os/mod.rs b/library/std/src/os/mod.rs
index 029f131c40be0..6182c5ad1c87b 100644
--- a/library/std/src/os/mod.rs
+++ b/library/std/src/os/mod.rs
@@ -129,6 +129,8 @@ pub mod illumos;
 pub mod ios;
 #[cfg(target_os = "l4re")]
 pub mod l4re;
+#[cfg(target_os = "watchos")]
+pub mod watchos;
 #[cfg(target_os = "macos")]
 pub mod macos;
 #[cfg(target_os = "netbsd")]
diff --git a/library/std/src/os/unix/mod.rs b/library/std/src/os/unix/mod.rs
index 7b8ca79eeb846..6a3b9bc8d5f1c 100644
--- a/library/std/src/os/unix/mod.rs
+++ b/library/std/src/os/unix/mod.rs
@@ -71,6 +71,8 @@ mod platform {
     pub use crate::os::solaris::*;
     #[cfg(target_os = "vxworks")]
     pub use crate::os::vxworks::*;
+    #[cfg(target_os = "watchos")]
+    pub use crate::os::watchos::*;
 }
 
 pub mod ffi;
@@ -88,6 +90,7 @@ pub mod thread;
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "watchos",
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd"
diff --git a/library/std/src/os/unix/net/stream.rs b/library/std/src/os/unix/net/stream.rs
index 3943b4fed0949..a97474055e574 100644
--- a/library/std/src/os/unix/net/stream.rs
+++ b/library/std/src/os/unix/net/stream.rs
@@ -20,6 +20,7 @@ use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, Owned
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "watchos",
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd"
@@ -38,6 +39,7 @@ use crate::time::Duration;
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "watchos",
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd"
@@ -246,6 +248,7 @@ impl UnixStream {
         target_os = "dragonfly",
         target_os = "freebsd",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "macos",
         target_os = "netbsd",
         target_os = "openbsd"
diff --git a/library/std/src/os/unix/ucred.rs b/library/std/src/os/unix/ucred.rs
index 32e6430d3f627..382d425c1a814 100644
--- a/library/std/src/os/unix/ucred.rs
+++ b/library/std/src/os/unix/ucred.rs
@@ -36,7 +36,7 @@ pub use self::impl_linux::peer_cred;
 ))]
 pub use self::impl_bsd::peer_cred;
 
-#[cfg(any(target_os = "macos", target_os = "ios",))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos",))]
 pub use self::impl_mac::peer_cred;
 
 #[cfg(any(target_os = "linux", target_os = "android"))]
@@ -97,7 +97,7 @@ pub mod impl_bsd {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios",))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos",))]
 pub mod impl_mac {
     use super::UCred;
     use crate::os::unix::io::AsRawFd;
diff --git a/library/std/src/os/unix/ucred/tests.rs b/library/std/src/os/unix/ucred/tests.rs
index 42d79418cf78f..3d9f4d8f3ad3f 100644
--- a/library/std/src/os/unix/ucred/tests.rs
+++ b/library/std/src/os/unix/ucred/tests.rs
@@ -8,6 +8,7 @@ use libc::{getegid, geteuid, getpid};
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "watchos",
     target_os = "macos",
     target_os = "openbsd"
 ))]
@@ -25,7 +26,7 @@ fn test_socket_pair() {
 }
 
 #[test]
-#[cfg(any(target_os = "linux", target_os = "ios", target_os = "macos",))]
+#[cfg(any(target_os = "linux", target_os = "ios", target_os = "macos", target_os = "watchos",))]
 fn test_socket_pair_pids(arg: Type) -> RetType {
     // Create two connected sockets and get their peer credentials.
     let (sock_a, sock_b) = UnixStream::pair().unwrap();
diff --git a/library/std/src/os/watchos/fs.rs b/library/std/src/os/watchos/fs.rs
new file mode 100644
index 0000000000000..3cf3d4a4521d5
--- /dev/null
+++ b/library/std/src/os/watchos/fs.rs
@@ -0,0 +1,142 @@
+#![stable(feature = "metadata_ext", since = "1.1.0")]
+
+use crate::fs::Metadata;
+use crate::sys_common::AsInner;
+
+#[allow(deprecated)]
+use crate::os::watchos::raw;
+
+/// OS-specific extensions to [`fs::Metadata`].
+///
+/// [`fs::Metadata`]: crate::fs::Metadata
+#[stable(feature = "metadata_ext", since = "1.1.0")]
+pub trait MetadataExt {
+    /// Gain a reference to the underlying `stat` structure which contains
+    /// the raw information returned by the OS.
+    ///
+    /// The contents of the returned `stat` are **not** consistent across
+    /// Unix platforms. The `os::unix::fs::MetadataExt` trait contains the
+    /// cross-Unix abstractions contained within the raw stat.
+    #[stable(feature = "metadata_ext", since = "1.1.0")]
+    #[rustc_deprecated(
+        since = "1.8.0",
+        reason = "deprecated in favor of the accessor \
+                  methods of this trait"
+    )]
+    #[allow(deprecated)]
+    fn as_raw_stat(&self) -> &raw::stat;
+
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_dev(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ino(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mode(&self) -> u32;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_nlink(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_uid(&self) -> u32;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_gid(&self) -> u32;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_rdev(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_size(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_atime(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_atime_nsec(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mtime(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mtime_nsec(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ctime(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ctime_nsec(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_birthtime(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_birthtime_nsec(&self) -> i64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_blksize(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_blocks(&self) -> u64;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_flags(&self) -> u32;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_gen(&self) -> u32;
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_lspare(&self) -> u32;
+}
+
+#[stable(feature = "metadata_ext", since = "1.1.0")]
+impl MetadataExt for Metadata {
+    #[allow(deprecated)]
+    fn as_raw_stat(&self) -> &raw::stat {
+        unsafe { &*(self.as_inner().as_inner() as *const libc::stat as *const raw::stat) }
+    }
+    fn st_dev(&self) -> u64 {
+        self.as_inner().as_inner().st_dev as u64
+    }
+    fn st_ino(&self) -> u64 {
+        self.as_inner().as_inner().st_ino as u64
+    }
+    fn st_mode(&self) -> u32 {
+        self.as_inner().as_inner().st_mode as u32
+    }
+    fn st_nlink(&self) -> u64 {
+        self.as_inner().as_inner().st_nlink as u64
+    }
+    fn st_uid(&self) -> u32 {
+        self.as_inner().as_inner().st_uid as u32
+    }
+    fn st_gid(&self) -> u32 {
+        self.as_inner().as_inner().st_gid as u32
+    }
+    fn st_rdev(&self) -> u64 {
+        self.as_inner().as_inner().st_rdev as u64
+    }
+    fn st_size(&self) -> u64 {
+        self.as_inner().as_inner().st_size as u64
+    }
+    fn st_atime(&self) -> i64 {
+        self.as_inner().as_inner().st_atime as i64
+    }
+    fn st_atime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_atime_nsec as i64
+    }
+    fn st_mtime(&self) -> i64 {
+        self.as_inner().as_inner().st_mtime as i64
+    }
+    fn st_mtime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_mtime_nsec as i64
+    }
+    fn st_ctime(&self) -> i64 {
+        self.as_inner().as_inner().st_ctime as i64
+    }
+    fn st_ctime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_ctime_nsec as i64
+    }
+    fn st_birthtime(&self) -> i64 {
+        self.as_inner().as_inner().st_birthtime as i64
+    }
+    fn st_birthtime_nsec(&self) -> i64 {
+        self.as_inner().as_inner().st_birthtime_nsec as i64
+    }
+    fn st_blksize(&self) -> u64 {
+        self.as_inner().as_inner().st_blksize as u64
+    }
+    fn st_blocks(&self) -> u64 {
+        self.as_inner().as_inner().st_blocks as u64
+    }
+    fn st_gen(&self) -> u32 {
+        self.as_inner().as_inner().st_gen as u32
+    }
+    fn st_flags(&self) -> u32 {
+        self.as_inner().as_inner().st_flags as u32
+    }
+    fn st_lspare(&self) -> u32 {
+        self.as_inner().as_inner().st_lspare as u32
+    }
+}
diff --git a/library/std/src/os/watchos/mod.rs b/library/std/src/os/watchos/mod.rs
new file mode 100644
index 0000000000000..cd6454ebbf99b
--- /dev/null
+++ b/library/std/src/os/watchos/mod.rs
@@ -0,0 +1,6 @@
+//! watchOS-specific definitions
+
+#![stable(feature = "raw_ext", since = "1.1.0")]
+
+pub mod fs;
+pub mod raw;
diff --git a/library/std/src/os/watchos/raw.rs b/library/std/src/os/watchos/raw.rs
new file mode 100644
index 0000000000000..d9d9995a5ac7f
--- /dev/null
+++ b/library/std/src/os/watchos/raw.rs
@@ -0,0 +1,83 @@
+//! watchOS-specific raw type definitions
+
+#![stable(feature = "raw_ext", since = "1.1.0")]
+#![rustc_deprecated(
+    since = "1.8.0",
+    reason = "these type aliases are no longer supported by \
+              the standard library, the `libc` crate on \
+              crates.io should be used instead for the correct \
+              definitions"
+)]
+#![allow(deprecated)]
+
+use crate::os::raw::c_long;
+
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type blkcnt_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type blksize_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type dev_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type ino_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type mode_t = u32;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type nlink_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type off_t = u64;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type time_t = i64;
+
+#[stable(feature = "pthread_t", since = "1.8.0")]
+pub type pthread_t = usize;
+
+#[repr(C)]
+#[derive(Clone)]
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub struct stat {
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_dev: i32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_mode: u16,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_nlink: u16,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_ino: u64,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_uid: u32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_gid: u32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_rdev: i32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_atime: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_atime_nsec: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_mtime: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_mtime_nsec: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_ctime: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_ctime_nsec: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_birthtime: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_birthtime_nsec: c_long,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_size: i64,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_blocks: i64,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_blksize: i32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_flags: u32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_gen: u32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_lspare: i32,
+    #[stable(feature = "raw_ext", since = "1.1.0")]
+    pub st_qspare: [i64; 2],
+}
diff --git a/library/std/src/sys/unix/args.rs b/library/std/src/sys/unix/args.rs
index ee5e3983ac26a..662b7d144006c 100644
--- a/library/std/src/sys/unix/args.rs
+++ b/library/std/src/sys/unix/args.rs
@@ -150,7 +150,7 @@ mod imp {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
 mod imp {
     use super::Args;
     use crate::ffi::CStr;
@@ -191,7 +191,7 @@ mod imp {
     // for i in (0..[args count])
     //      res.push([args objectAtIndex:i])
     // res
-    #[cfg(target_os = "ios")]
+    #[cfg(any(target_os = "ios", target_os = "watchos"))]
     pub fn args() -> Args {
         use crate::ffi::OsString;
         use crate::mem;
diff --git a/library/std/src/sys/unix/env.rs b/library/std/src/sys/unix/env.rs
index 60551aeb3e73e..63c5f99974fdb 100644
--- a/library/std/src/sys/unix/env.rs
+++ b/library/std/src/sys/unix/env.rs
@@ -31,6 +31,17 @@ pub mod os {
     pub const EXE_EXTENSION: &str = "";
 }
 
+#[cfg(target_os = "watchos")]
+pub mod os {
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "watchos";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".dylib";
+    pub const DLL_EXTENSION: &str = "dylib";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
+}
+
 #[cfg(target_os = "freebsd")]
 pub mod os {
     pub const FAMILY: &str = "unix";
diff --git a/library/std/src/sys/unix/fd.rs b/library/std/src/sys/unix/fd.rs
index 3de7c68a6866d..c957b69934d93 100644
--- a/library/std/src/sys/unix/fd.rs
+++ b/library/std/src/sys/unix/fd.rs
@@ -31,6 +31,7 @@ const READ_LIMIT: usize = libc::ssize_t::MAX as usize;
     target_os = "dragonfly",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "watchos",
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd",
@@ -50,6 +51,7 @@ const fn max_iov() -> usize {
     target_os = "emscripten",
     target_os = "freebsd",
     target_os = "ios",
+    target_os = "watchos",
     target_os = "linux",
     target_os = "macos",
     target_os = "netbsd",
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index b93a3d677711f..8230fb9b76e78 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -394,7 +394,8 @@ impl FileAttr {
         target_os = "freebsd",
         target_os = "openbsd",
         target_os = "macos",
-        target_os = "ios"
+        target_os = "ios",
+        target_os = "watchos"
     ))]
     pub fn created(&self) -> io::Result<SystemTime> {
         Ok(SystemTime::from(libc::timespec {
@@ -407,7 +408,8 @@ impl FileAttr {
         target_os = "freebsd",
         target_os = "openbsd",
         target_os = "macos",
-        target_os = "ios"
+        target_os = "ios",
+        target_os = "watchos"
     )))]
     pub fn created(&self) -> io::Result<SystemTime> {
         cfg_has_statx! {
@@ -664,6 +666,7 @@ impl DirEntry {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "linux",
         target_os = "emscripten",
         target_os = "android",
@@ -693,6 +696,7 @@ impl DirEntry {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "netbsd",
         target_os = "openbsd",
         target_os = "freebsd",
@@ -867,11 +871,11 @@ impl File {
         cvt_r(|| unsafe { os_fsync(self.as_raw_fd()) })?;
         return Ok(());
 
-        #[cfg(any(target_os = "macos", target_os = "ios"))]
+        #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
         unsafe fn os_fsync(fd: c_int) -> c_int {
             libc::fcntl(fd, libc::F_FULLFSYNC)
         }
-        #[cfg(not(any(target_os = "macos", target_os = "ios")))]
+        #[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "watchos")))]
         unsafe fn os_fsync(fd: c_int) -> c_int {
             libc::fsync(fd)
         }
@@ -881,7 +885,7 @@ impl File {
         cvt_r(|| unsafe { os_datasync(self.as_raw_fd()) })?;
         return Ok(());
 
-        #[cfg(any(target_os = "macos", target_os = "ios"))]
+        #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
         unsafe fn os_datasync(fd: c_int) -> c_int {
             libc::fcntl(fd, libc::F_FULLFSYNC)
         }
@@ -899,6 +903,7 @@ impl File {
             target_os = "android",
             target_os = "freebsd",
             target_os = "ios",
+            target_os = "watchos",
             target_os = "linux",
             target_os = "macos",
             target_os = "netbsd",
@@ -1353,7 +1358,8 @@ fn open_to_and_set_permissions(
     target_os = "linux",
     target_os = "android",
     target_os = "macos",
-    target_os = "ios"
+    target_os = "ios",
+    target_os = "watchos"
 )))]
 pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
     let (mut reader, reader_metadata) = open_from(from)?;
@@ -1380,7 +1386,7 @@ pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
 pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
     use crate::sync::atomic::{AtomicBool, Ordering};
 
diff --git a/library/std/src/sys/unix/locks/pthread_condvar.rs b/library/std/src/sys/unix/locks/pthread_condvar.rs
index 099aa68706fa3..210b41fb45e97 100644
--- a/library/std/src/sys/unix/locks/pthread_condvar.rs
+++ b/library/std/src/sys/unix/locks/pthread_condvar.rs
@@ -28,6 +28,7 @@ impl Condvar {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "l4re",
         target_os = "android",
         target_os = "redox"
@@ -47,6 +48,7 @@ impl Condvar {
     #[cfg(not(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "l4re",
         target_os = "android",
         target_os = "redox",
@@ -90,8 +92,10 @@ impl Condvar {
     #[cfg(not(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "android",
         target_os = "espidf"
+        target_os = "android",
     )))]
     pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
         use crate::mem;
@@ -122,8 +126,10 @@ impl Condvar {
     #[cfg(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "android",
         target_os = "espidf"
+        target_os = "android",
     ))]
     pub unsafe fn wait_timeout(&self, mutex: &Mutex, mut dur: Duration) -> bool {
         use crate::ptr;
diff --git a/library/std/src/sys/unix/mod.rs b/library/std/src/sys/unix/mod.rs
index e65c11b6d09fa..fb1313f2b7237 100644
--- a/library/std/src/sys/unix/mod.rs
+++ b/library/std/src/sys/unix/mod.rs
@@ -77,6 +77,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8) {
                 // The poll on Darwin doesn't set POLLNVAL for closed fds.
                 target_os = "macos",
                 target_os = "ios",
+                target_os = "watchos",
                 target_os = "redox",
                 target_os = "l4re",
             )))] {
@@ -104,7 +105,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8) {
                         libc::abort();
                     }
                 }
-            } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "redox"))] {
+            } else if #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos", target_os = "redox"))] {
                 use crate::sys::os::errno;
                 for fd in 0..3 {
                     if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
@@ -295,7 +296,7 @@ cfg_if::cfg_if! {
         // See #41582 and https://blog.achernya.com/2013/03/os-x-has-silly-libsystem.html
         #[link(name = "resolv")]
         extern "C" {}
-    } else if #[cfg(target_os = "ios")] {
+    } else if #[cfg(any(target_os = "ios", target_os = "watchos"))] {
         #[link(name = "System")]
         #[link(name = "objc")]
         #[link(name = "Security", kind = "framework")]
diff --git a/library/std/src/sys/unix/os.rs b/library/std/src/sys/unix/os.rs
index 0b6cdb923bd6a..44797b420ecae 100644
--- a/library/std/src/sys/unix/os.rs
+++ b/library/std/src/sys/unix/os.rs
@@ -61,7 +61,7 @@ extern "C" {
     )]
     #[cfg_attr(any(target_os = "solaris", target_os = "illumos"), link_name = "___errno")]
     #[cfg_attr(
-        any(target_os = "macos", target_os = "ios", target_os = "freebsd"),
+        any(target_os = "macos", target_os = "ios", target_os = "watchos", target_os = "freebsd"),
         link_name = "__error"
     )]
     #[cfg_attr(target_os = "haiku", link_name = "_errnop")]
@@ -361,7 +361,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
 pub fn current_exe() -> io::Result<PathBuf> {
     unsafe {
         let mut sz: u32 = 0;
@@ -578,6 +578,7 @@ pub fn home_dir() -> Option<PathBuf> {
     #[cfg(any(
         target_os = "android",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "emscripten",
         target_os = "redox",
         target_os = "vxworks",
@@ -589,6 +590,7 @@ pub fn home_dir() -> Option<PathBuf> {
     #[cfg(not(any(
         target_os = "android",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "emscripten",
         target_os = "redox",
         target_os = "vxworks",
diff --git a/library/std/src/sys/unix/rand.rs b/library/std/src/sys/unix/rand.rs
index 17e8efbe097ce..6ecb8546d48f8 100644
--- a/library/std/src/sys/unix/rand.rs
+++ b/library/std/src/sys/unix/rand.rs
@@ -14,6 +14,7 @@ pub fn hashmap_random_keys() -> (u64, u64) {
     unix,
     not(target_os = "macos"),
     not(target_os = "ios"),
+    not(target_os = "watchos"),
     not(target_os = "openbsd"),
     not(target_os = "freebsd"),
     not(target_os = "netbsd"),
@@ -170,7 +171,7 @@ mod imp {
 // once per thread in `hashmap_random_keys`. Therefore `SecRandomCopyBytes` is
 // only used on iOS where direct access to `/dev/urandom` is blocked by the
 // sandbox.
-#[cfg(target_os = "ios")]
+#[cfg(any(target_os = "ios", target_os = "watchos"))]
 mod imp {
     use crate::io;
     use crate::ptr;
diff --git a/library/std/src/sys/unix/thread.rs b/library/std/src/sys/unix/thread.rs
index 2d5d306ed62bb..f121f5045e41c 100644
--- a/library/std/src/sys/unix/thread.rs
+++ b/library/std/src/sys/unix/thread.rs
@@ -133,7 +133,7 @@ impl Thread {
         }
     }
 
-    #[cfg(any(target_os = "macos", target_os = "ios"))]
+    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
     pub fn set_name(name: &CStr) {
         unsafe {
             libc::pthread_setname_np(name.as_ptr());
diff --git a/library/std/src/sys/unix/time.rs b/library/std/src/sys/unix/time.rs
index 59ddd1aa92f81..c594ec9e7192b 100644
--- a/library/std/src/sys/unix/time.rs
+++ b/library/std/src/sys/unix/time.rs
@@ -114,7 +114,7 @@ impl Hash for Timespec {
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
 mod inner {
     use crate::fmt;
     use crate::sync::atomic::{AtomicU64, Ordering};
@@ -263,7 +263,7 @@ mod inner {
     }
 }
 
-#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+#[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "watchos")))]
 mod inner {
     use crate::fmt;
     use crate::sys::cvt;
diff --git a/library/std/src/sys_common/net.rs b/library/std/src/sys_common/net.rs
index 3b7cdd55a081c..c3b6ba9a6e4e6 100644
--- a/library/std/src/sys_common/net.rs
+++ b/library/std/src/sys_common/net.rs
@@ -19,7 +19,7 @@ use libc::{c_int, c_void};
 cfg_if::cfg_if! {
     if #[cfg(any(
         target_os = "dragonfly", target_os = "freebsd",
-        target_os = "ios", target_os = "macos",
+        target_os = "ios", target_os = "macos", target_os = "watchos",
         target_os = "openbsd", target_os = "netbsd", target_os = "illumos",
         target_os = "solaris", target_os = "haiku", target_os = "l4re"))] {
         use crate::sys::net::netc::IPV6_JOIN_GROUP as IPV6_ADD_MEMBERSHIP;
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index a810a57feb7bb..256059b43760b 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -231,7 +231,10 @@ impl Step for Llvm {
         }
 
         // Are we compiling for iOS/tvOS?
-        if target.contains("apple-ios") || target.contains("apple-tvos") {
+        if target.contains("apple-ios")
+            || target.contains("apple-tvos")
+            || target.contains("apple-watchos")
+        {
             // These two defines prevent CMake from automatically trying to add a MacOSX sysroot, which leads to a compiler error.
             cfg.define("CMAKE_OSX_SYSROOT", "/");
             cfg.define("CMAKE_OSX_DEPLOYMENT_TARGET", "");
diff --git a/src/tools/compiletest/src/raise_fd_limit.rs b/src/tools/compiletest/src/raise_fd_limit.rs
index faded7c802483..a76df2bd7368b 100644
--- a/src/tools/compiletest/src/raise_fd_limit.rs
+++ b/src/tools/compiletest/src/raise_fd_limit.rs
@@ -50,5 +50,5 @@ pub unsafe fn raise_fd_limit() {
     }
 }
 
-#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+#[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "watchos")))]
 pub unsafe fn raise_fd_limit() {}
diff --git a/src/tools/compiletest/src/util.rs b/src/tools/compiletest/src/util.rs
index bed509d77be77..bbcd81a74e438 100644
--- a/src/tools/compiletest/src/util.rs
+++ b/src/tools/compiletest/src/util.rs
@@ -22,6 +22,7 @@ const OS_TABLE: &[(&str, &str)] = &[
     ("hermit", "hermit"),
     ("illumos", "illumos"),
     ("ios", "ios"),
+    ("watchos", "watchos"),
     ("l4re", "l4re"),
     ("linux", "linux"),
     ("mingw32", "windows"),

From 5aee29bb997bba377c4c265dd22a7b66a43857e6 Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Sun, 20 Jun 2021 08:43:53 +0100
Subject: [PATCH 03/10] [watchos] Add bitcode for armv7k, fix unwind for armv7k

---
 .../rustc_target/src/spec/armv7k_apple_watchos.rs     | 11 +++++++++++
 library/panic_unwind/src/dwarf/eh.rs                  |  2 +-
 library/unwind/src/libunwind.rs                       |  2 +-
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
index 5fe07264d095b..2f672ae06533d 100644
--- a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
+++ b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
@@ -12,6 +12,17 @@ pub fn target() -> Target {
             features: "+v7,+vfp4,+neon".to_string(),
             max_atomic_width: Some(64),
             unsupported_abis: super::arm_base::unsupported_abis(),
+            forces_embed_bitcode: true,
+            // These arguments are not actually invoked - they just have
+            // to look right to pass App Store validation.
+            bitcode_llvm_cmdline: "-triple\0\
+                armv7k-apple-watchos3.0.0\0\
+                -emit-obj\0\
+                -disable-llvm-passes\0\
+                -target-abi\0\
+                darwinpcs\0\
+                -Os\0"
+                .to_string(),
             ..base
         },
     }
diff --git a/library/panic_unwind/src/dwarf/eh.rs b/library/panic_unwind/src/dwarf/eh.rs
index 44086cd141e59..8d59fa43ad996 100644
--- a/library/panic_unwind/src/dwarf/eh.rs
+++ b/library/panic_unwind/src/dwarf/eh.rs
@@ -50,7 +50,7 @@ pub enum EHAction {
 }
 
 pub const USING_SJLJ_EXCEPTIONS: bool =
-    cfg!(all(any(target_os = "ios", target_os = "watchos"), target_arch = "arm"));
+    cfg!(all(target_os = "ios", target_arch = "arm"));
 
 pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>) -> Result<EHAction, ()> {
     if lsda.is_null() {
diff --git a/library/unwind/src/libunwind.rs b/library/unwind/src/libunwind.rs
index 380d8ec6838e0..cfe4290ca9953 100644
--- a/library/unwind/src/libunwind.rs
+++ b/library/unwind/src/libunwind.rs
@@ -240,7 +240,7 @@ if #[cfg(any(target_os = "ios", target_os = "watchos", target_os = "netbsd", not
 } // cfg_if!
 
 cfg_if::cfg_if! {
-if #[cfg(not(all(any(target_os = "ios", target_os = "watchos"), target_arch = "arm")))] {
+if #[cfg(not(all(target_os = "ios", target_arch = "arm")))] {
     // Not 32-bit iOS
     #[cfg_attr(
         all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),

From de13bd335bfd537faf4c7bcad85f611e361c981e Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 14:18:53 +0000
Subject: [PATCH 04/10] [watchos] Update WatchOs support - add to supported
 platforms

---
 Cargo.lock                                          | 13 +++++--------
 Cargo.toml                                          |  7 +++++--
 compiler/rustc_codegen_ssa/src/back/link.rs         |  4 ++--
 compiler/rustc_target/src/spec/apple_sdk_base.rs    |  2 +-
 .../rustc_target/src/spec/arm64_32_apple_watchos.rs |  1 -
 .../rustc_target/src/spec/armv7k_apple_watchos.rs   |  1 -
 .../src/spec/x86_64_apple_watchos_sim.rs            |  6 +++---
 library/std/src/sys/unix/fs.rs                      |  3 +++
 library/std/src/sys/unix/locks/pthread_condvar.rs   |  2 --
 library/unwind/src/libunwind.rs                     |  2 +-
 src/doc/rustc/src/platform-support.md               |  3 +++
 11 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 48518008b7d45..62c35678d54e9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -490,9 +490,8 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.0.69"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e70cc2f62c6ce1868963827bd677764c62d07c3d9a3e1fb1177ee1a9ab199eb2"
+version = "1.0.73"
+source = "git+https://github.com/alexcrichton/cc-rs?rev=refs/pull/662/head#73f8fe4b5c0024d855398e4fa4ae68b5b82221f2"
 dependencies = [
  "jobserver",
 ]
@@ -734,8 +733,7 @@ dependencies = [
 [[package]]
 name = "compiler_builtins"
 version = "0.1.70"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80873f979f0a344a4ade87c2f70d9ccf5720b83b10c97ec7cd745895d021e85a"
+source = "git+https://github.com/rust-lang/compiler-builtins?rev=refs/pull/456/head#eb68e3a2f2a0bd4ea625e4287c2eb2069d1c4fa2"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",
@@ -1965,9 +1963,8 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.116"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "565dbd88872dbe4cc8a46e527f26483c1d1f7afa6b884a3bd6cd893d4f98da74"
+version = "0.2.119"
+source = "git+https://github.com/rust-lang/libc?rev=refs/pull/2717/head#f073685f728891f104bf2125f1bcb9f123cf5d3b"
 dependencies = [
  "rustc-std-workspace-core",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 0ec3f510ea81f..938510f0eef6c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -125,8 +125,11 @@ rustfmt-nightly = { path = "src/tools/rustfmt" }
 # See comments in `src/tools/rustc-workspace-hack/README.md` for what's going on
 # here
 rustc-workspace-hack = { path = 'src/tools/rustc-workspace-hack' }
-cc = { git = "https://github.com/vladimir-ea/cc-rs", branch = "watch_os" }
-libc = { git = "https://github.com/vladimir-ea/libc", branch = "watch_os" }
+
+# TODO prerequisite changes
+compiler_builtins =  { git = "https://github.com/rust-lang/compiler-builtins", rev = "refs/pull/456/head" }
+cc = { git = "https://github.com/alexcrichton/cc-rs", rev = "refs/pull/662/head" }
+libc = { git = "https://github.com/rust-lang/libc", rev = "refs/pull/2717/head" }
 
 # See comments in `library/rustc-std-workspace-core/README.md` for what's going on
 # here
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 5d188e304dc38..845091eae0d7e 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -2475,7 +2475,7 @@ fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
         ("x86_64", "watchos") => "watchsimulator",
         ("arm64_32", "watchos") => "watchos",
         ("aarch64", "watchos") => "watchos",
-        ("armv7k", "watchos") => "watchos",
+        ("arm", "watchos") => "watchos",
         _ => {
             sess.err(&format!("unsupported arch `{}` for os `{}`", arch, os));
             return;
@@ -2533,7 +2533,7 @@ fn get_apple_sdk_root(sdk_name: &str) -> Result<String, String> {
         }
     }
     let res =
-        Command::new("xcrunp").arg("--show-sdk-path").arg("-sdk").arg(sdk_name).output().and_then(
+        Command::new("xcrun").arg("--show-sdk-path").arg("-sdk").arg(sdk_name).output().and_then(
             |output| {
                 if output.status.success() {
                     Ok(String::from_utf8(output.stdout).unwrap())
diff --git a/compiler/rustc_target/src/spec/apple_sdk_base.rs b/compiler/rustc_target/src/spec/apple_sdk_base.rs
index 0bcccf1df2d93..dae782169168f 100644
--- a/compiler/rustc_target/src/spec/apple_sdk_base.rs
+++ b/compiler/rustc_target/src/spec/apple_sdk_base.rs
@@ -18,7 +18,7 @@ pub enum Arch {
 
 fn target_abi(arch: Arch) -> String {
     match arch {
-        Armv7 | Armv7s | Arm64 | I386 | X86_64 => "",
+        Armv7 | Armv7k | Armv7s | Arm64 | Arm64_32 | I386 | X86_64 => "",
         X86_64_macabi | Arm64_macabi => "macabi",
         Arm64_sim => "sim",
     }
diff --git a/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs b/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs
index 504bcd63052c7..54bb8c93ab9df 100644
--- a/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs
+++ b/compiler/rustc_target/src/spec/arm64_32_apple_watchos.rs
@@ -11,7 +11,6 @@ pub fn target() -> Target {
         options: TargetOptions {
             features: "+neon,+fp-armv8,+apple-a7".to_string(),
             max_atomic_width: Some(64),
-            unsupported_abis: super::arm_base::unsupported_abis(),
             forces_embed_bitcode: true,
             // These arguments are not actually invoked - they just have
             // to look right to pass App Store validation.
diff --git a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
index 2f672ae06533d..fef027e999f69 100644
--- a/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
+++ b/compiler/rustc_target/src/spec/armv7k_apple_watchos.rs
@@ -11,7 +11,6 @@ pub fn target() -> Target {
         options: TargetOptions {
             features: "+v7,+vfp4,+neon".to_string(),
             max_atomic_width: Some(64),
-            unsupported_abis: super::arm_base::unsupported_abis(),
             forces_embed_bitcode: true,
             // These arguments are not actually invoked - they just have
             // to look right to pass App Store validation.
diff --git a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
index 638f36a8bcba1..e52156876d948 100644
--- a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
+++ b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
@@ -1,5 +1,5 @@
 use super::apple_sdk_base::{opts, Arch};
-use crate::spec::{StackProbeType, Target, TargetOptions};
+use crate::spec::{StackProbeType, Target, TargetOptions, LinkerFlavor, LldFlavor};
 
 pub fn target() -> Target {
     let base = opts("watchos", Arch::X86_64);
@@ -8,9 +8,9 @@ pub fn target() -> Target {
     let llvm_target = super::apple_base::watchos_sim_llvm_target(arch);
 
     Target {
-        llvm_target: llvm_target,
+        llvm_target,
         pointer_width: 64,
-        data_layout: "e-m:o-i64:64-f80:128-n8:16:32:64-S128".to_string(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128".to_string(),
         arch: "x86_64".to_string(),
         options: TargetOptions {
             max_atomic_width: Some(64),
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index 8230fb9b76e78..e9b039c467828 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -17,6 +17,7 @@ use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
     all(target_os = "linux", target_env = "gnu"),
     target_os = "macos",
     target_os = "ios",
+    target_os = "watchos",
 ))]
 use crate::sys::weak::syscall;
 #[cfg(target_os = "macos")]
@@ -27,6 +28,7 @@ use libc::{c_int, mode_t};
 #[cfg(any(
     target_os = "macos",
     target_os = "ios",
+    target_os = "watchos",
     all(target_os = "linux", target_env = "gnu")
 ))]
 use libc::c_char;
@@ -714,6 +716,7 @@ impl DirEntry {
     #[cfg(not(any(
         target_os = "macos",
         target_os = "ios",
+        target_os = "watchos",
         target_os = "netbsd",
         target_os = "openbsd",
         target_os = "freebsd",
diff --git a/library/std/src/sys/unix/locks/pthread_condvar.rs b/library/std/src/sys/unix/locks/pthread_condvar.rs
index 210b41fb45e97..6b14d55e8433e 100644
--- a/library/std/src/sys/unix/locks/pthread_condvar.rs
+++ b/library/std/src/sys/unix/locks/pthread_condvar.rs
@@ -95,7 +95,6 @@ impl Condvar {
         target_os = "watchos",
         target_os = "android",
         target_os = "espidf"
-        target_os = "android",
     )))]
     pub unsafe fn wait_timeout(&self, mutex: &Mutex, dur: Duration) -> bool {
         use crate::mem;
@@ -129,7 +128,6 @@ impl Condvar {
         target_os = "watchos",
         target_os = "android",
         target_os = "espidf"
-        target_os = "android",
     ))]
     pub unsafe fn wait_timeout(&self, mutex: &Mutex, mut dur: Duration) -> bool {
         use crate::ptr;
diff --git a/library/unwind/src/libunwind.rs b/library/unwind/src/libunwind.rs
index cfe4290ca9953..25e96d2ad398e 100644
--- a/library/unwind/src/libunwind.rs
+++ b/library/unwind/src/libunwind.rs
@@ -33,7 +33,7 @@ pub const unwinder_private_data_size: usize = 6;
 #[cfg(all(target_arch = "arm", not(any(target_os = "ios", target_os = "watchos"))))]
 pub const unwinder_private_data_size: usize = 20;
 
-#[cfg(all(target_arch = "arm", any(target_os = "ios", target_os = "watchos")))]
+#[cfg(all(any(target_arch = "arm", target_arch="arm64_32"), any(target_os = "ios", target_os = "watchos")))]
 pub const unwinder_private_data_size: usize = 5;
 
 #[cfg(all(target_arch = "aarch64", target_pointer_width = "64"))]
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index cc92d273ed1c5..a1675828cd594 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -217,6 +217,7 @@ target | std | host | notes
 `aarch64-wrs-vxworks` | ? |  |
 `aarch64_be-unknown-linux-gnu_ilp32` | ✓ | ✓ | ARM64 Linux (big-endian, ILP32 ABI)
 `aarch64_be-unknown-linux-gnu` | ✓ | ✓ | ARM64 Linux (big-endian)
+`arm64_32-apple-watchos` | ✓ | | ARM Apple WatchOS 64-bit with 32-bit pointers
 `armv4t-unknown-linux-gnueabi` | ? |  |
 `armv5te-unknown-linux-uclibceabi` | ? |  | ARMv5TE Linux with uClibc
 `armv6-unknown-freebsd` | ✓ | ✓ | ARMv6 FreeBSD
@@ -231,6 +232,7 @@ target | std | host | notes
 [`armv7a-kmc-solid_asp3-eabi`](platform-support/kmc-solid.md) | ✓ |  | ARM SOLID with TOPPERS/ASP3
 [`armv7a-kmc-solid_asp3-eabihf`](platform-support/kmc-solid.md) | ✓ |  | ARM SOLID with TOPPERS/ASP3, hardfloat
 `armv7a-none-eabihf` | * | | ARM Cortex-A, hardfloat
+`armv7k-apple-watchos` | ✓ | | ARM Apple WatchOS
 `armv7s-apple-ios` | ✓ |  |
 `avr-unknown-gnu-atmega328` | * |  | AVR. Requires `-Z build-std=core`
 `bpfeb-unknown-none` | * |  | BPF (big endian)
@@ -286,6 +288,7 @@ target | std | host | notes
 [`wasm64-unknown-unknown`](platform-support/wasm64-unknown-unknown.md) | ? |  | WebAssembly
 `x86_64-apple-ios-macabi` | ✓ |  | Apple Catalyst on x86_64
 `x86_64-apple-tvos` | * | | x86 64-bit tvOS
+`x86_64-apple-watchos-sim` | ✓ | | x86 64-bit Apple WatchOS simulator
 `x86_64-pc-windows-msvc` | * |  | 64-bit Windows XP support
 `x86_64-sun-solaris` | ? |  | Deprecated target for 64-bit Solaris 10/11, illumos
 `x86_64-unknown-dragonfly` | ✓ | ✓ | 64-bit DragonFlyBSD

From 5fbf86938065c0e9ec51c69bd731a049f7fa8e5a Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 14:39:35 +0000
Subject: [PATCH 05/10] [watchos] Remove unused imports in spec

---
 compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
index e52156876d948..878ece8bcd628 100644
--- a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
+++ b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
@@ -1,5 +1,5 @@
 use super::apple_sdk_base::{opts, Arch};
-use crate::spec::{StackProbeType, Target, TargetOptions, LinkerFlavor, LldFlavor};
+use crate::spec::{StackProbeType, Target, TargetOptions};
 
 pub fn target() -> Target {
     let base = opts("watchos", Arch::X86_64);

From 29c4c8bb3b481bdad76854ee55caca4464d592ff Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 15:04:52 +0000
Subject: [PATCH 06/10] [watchos] remove crate patches

---
 Cargo.lock | 9 ++++++---
 Cargo.toml | 5 -----
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 62c35678d54e9..6ea32af3dea62 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -491,7 +491,8 @@ version = "0.1.0"
 [[package]]
 name = "cc"
 version = "1.0.73"
-source = "git+https://github.com/alexcrichton/cc-rs?rev=refs/pull/662/head#73f8fe4b5c0024d855398e4fa4ae68b5b82221f2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
 dependencies = [
  "jobserver",
 ]
@@ -733,7 +734,8 @@ dependencies = [
 [[package]]
 name = "compiler_builtins"
 version = "0.1.70"
-source = "git+https://github.com/rust-lang/compiler-builtins?rev=refs/pull/456/head#eb68e3a2f2a0bd4ea625e4287c2eb2069d1c4fa2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "80873f979f0a344a4ade87c2f70d9ccf5720b83b10c97ec7cd745895d021e85a"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",
@@ -1964,7 +1966,8 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 [[package]]
 name = "libc"
 version = "0.2.119"
-source = "git+https://github.com/rust-lang/libc?rev=refs/pull/2717/head#f073685f728891f104bf2125f1bcb9f123cf5d3b"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bf2e165bb3457c8e098ea76f3e3bc9db55f87aa90d52d0e6be741470916aaa4"
 dependencies = [
  "rustc-std-workspace-core",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 938510f0eef6c..4e78399606445 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -126,11 +126,6 @@ rustfmt-nightly = { path = "src/tools/rustfmt" }
 # here
 rustc-workspace-hack = { path = 'src/tools/rustc-workspace-hack' }
 
-# TODO prerequisite changes
-compiler_builtins =  { git = "https://github.com/rust-lang/compiler-builtins", rev = "refs/pull/456/head" }
-cc = { git = "https://github.com/alexcrichton/cc-rs", rev = "refs/pull/662/head" }
-libc = { git = "https://github.com/rust-lang/libc", rev = "refs/pull/2717/head" }
-
 # See comments in `library/rustc-std-workspace-core/README.md` for what's going on
 # here
 rustc-std-workspace-core = { path = 'library/rustc-std-workspace-core' }

From a92030ad19c0ed76e4fd3d23b372a5e85109e8e4 Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 15:23:53 +0000
Subject: [PATCH 07/10] [watchos] fix format

---
 library/panic_unwind/src/dwarf/eh.rs | 3 +--
 library/std/src/os/mod.rs            | 5 ++---
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/library/panic_unwind/src/dwarf/eh.rs b/library/panic_unwind/src/dwarf/eh.rs
index 8d59fa43ad996..7394feab82f22 100644
--- a/library/panic_unwind/src/dwarf/eh.rs
+++ b/library/panic_unwind/src/dwarf/eh.rs
@@ -49,8 +49,7 @@ pub enum EHAction {
     Terminate,
 }
 
-pub const USING_SJLJ_EXCEPTIONS: bool =
-    cfg!(all(target_os = "ios", target_arch = "arm"));
+pub const USING_SJLJ_EXCEPTIONS: bool = cfg!(all(target_os = "ios", target_arch = "arm"));
 
 pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>) -> Result<EHAction, ()> {
     if lsda.is_null() {
diff --git a/library/std/src/os/mod.rs b/library/std/src/os/mod.rs
index 6182c5ad1c87b..241ee4cfe5c1a 100644
--- a/library/std/src/os/mod.rs
+++ b/library/std/src/os/mod.rs
@@ -129,8 +129,6 @@ pub mod illumos;
 pub mod ios;
 #[cfg(target_os = "l4re")]
 pub mod l4re;
-#[cfg(target_os = "watchos")]
-pub mod watchos;
 #[cfg(target_os = "macos")]
 pub mod macos;
 #[cfg(target_os = "netbsd")]
@@ -141,11 +139,12 @@ pub mod openbsd;
 pub mod redox;
 #[cfg(target_os = "solaris")]
 pub mod solaris;
-
 #[cfg(target_os = "solid_asp3")]
 pub mod solid;
 #[cfg(target_os = "vxworks")]
 pub mod vxworks;
+#[cfg(target_os = "watchos")]
+pub mod watchos;
 
 #[cfg(any(unix, target_os = "wasi", doc))]
 mod fd;

From e57296d6650d3e5685fabb00d59c37bfe22adf8c Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 15:38:23 +0000
Subject: [PATCH 08/10] [watchos] more format fix

---
 library/unwind/src/libunwind.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/library/unwind/src/libunwind.rs b/library/unwind/src/libunwind.rs
index 25e96d2ad398e..4b9df5d4fd768 100644
--- a/library/unwind/src/libunwind.rs
+++ b/library/unwind/src/libunwind.rs
@@ -33,7 +33,10 @@ pub const unwinder_private_data_size: usize = 6;
 #[cfg(all(target_arch = "arm", not(any(target_os = "ios", target_os = "watchos"))))]
 pub const unwinder_private_data_size: usize = 20;
 
-#[cfg(all(any(target_arch = "arm", target_arch="arm64_32"), any(target_os = "ios", target_os = "watchos")))]
+#[cfg(all(
+    any(target_arch = "arm", target_arch = "arm64_32"),
+    any(target_os = "ios", target_os = "watchos")
+))]
 pub const unwinder_private_data_size: usize = 5;
 
 #[cfg(all(target_arch = "aarch64", target_pointer_width = "64"))]

From 44cb1417833b19aecdb8ed2c5bd9941d1e65b20c Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 16:06:15 +0000
Subject: [PATCH 09/10] [watchos] fix formatting

---
 compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
index 878ece8bcd628..77dc7938e0873 100644
--- a/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
+++ b/compiler/rustc_target/src/spec/x86_64_apple_watchos_sim.rs
@@ -10,7 +10,8 @@ pub fn target() -> Target {
     Target {
         llvm_target,
         pointer_width: 64,
-        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128".to_string(),
+        data_layout: "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+            .to_string(),
         arch: "x86_64".to_string(),
         options: TargetOptions {
             max_atomic_width: Some(64),

From 71711b9961af8c9c0a1b62a5b5ba0441de0ccb5a Mon Sep 17 00:00:00 2001
From: Vladimir Michael Eatwell <dimir@fb.com>
Date: Tue, 8 Mar 2022 16:41:26 +0000
Subject: [PATCH 10/10] [watchos] Update expected cfg-check output to include
 watchos

---
 src/test/ui/check-cfg/well-known-values.stderr | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/ui/check-cfg/well-known-values.stderr b/src/test/ui/check-cfg/well-known-values.stderr
index 8b04c770fb505..4364d630b586f 100644
--- a/src/test/ui/check-cfg/well-known-values.stderr
+++ b/src/test/ui/check-cfg/well-known-values.stderr
@@ -7,7 +7,7 @@ LL | #[cfg(target_os = "linuz")]
    |                   help: did you mean: `"linux"`
    |
    = note: `#[warn(unexpected_cfgs)]` on by default
-   = note: expected values for `target_os` are: android, cuda, dragonfly, emscripten, espidf, freebsd, fuchsia, haiku, hermit, horizon, illumos, ios, l4re, linux, macos, netbsd, none, openbsd, psp, redox, solaris, solid_asp3, tvos, uefi, unknown, vxworks, wasi, windows
+   = note: expected values for `target_os` are: android, cuda, dragonfly, emscripten, espidf, freebsd, fuchsia, haiku, hermit, horizon, illumos, ios, l4re, linux, macos, netbsd, none, openbsd, psp, redox, solaris, solid_asp3, tvos, uefi, unknown, vxworks, wasi, watchos, windows
 
 warning: unexpected `cfg` condition value
   --> $DIR/well-known-values.rs:14:7