Add target_env = "macabi" and target_env = "sim"

2 files changed, 25 insertions, 0 deletions

diff --git a/src/doc/rustc/src/platform-support/apple-ios-macabi.md b/src/doc/rustc/src/platform-support/apple-ios-macabi.md
index d4b71dbd4f4..c6f68f7a1e8 100644
--- a/src/doc/rustc/src/platform-support/apple-ios-macabi.md
+++ b/src/doc/rustc/src/platform-support/apple-ios-macabi.md
@@ -56,6 +56,17 @@ Rust programs can be built for these targets by specifying `--target`, if
 $ rustc --target aarch64-apple-ios-macabi your-code.rs
 ```
 
+The target can be differentiated from the iOS targets with the
+`target_env = "macabi"` cfg (or `target_abi = "macabi"` before Rust CURRENT_RUSTC_VERSION).
+
+```rust
+if cfg!(target_env = "macabi") {
+    // Do something only on Mac Catalyst.
+}
+```
+
+This is similar to the `TARGET_OS_MACCATALYST` define in C code.
+
 ## Testing
 
 Mac Catalyst binaries can be run directly on macOS 10.15 Catalina or newer.
diff --git a/src/doc/rustc/src/platform-support/apple-ios.md b/src/doc/rustc/src/platform-support/apple-ios.md
index 64325554ab6..586afa65226 100644
--- a/src/doc/rustc/src/platform-support/apple-ios.md
+++ b/src/doc/rustc/src/platform-support/apple-ios.md
@@ -66,6 +66,20 @@ Rust programs can be built for these targets by specifying `--target`, if
 $ rustc --target aarch64-apple-ios your-code.rs
 ```
 
+The simulator variants can be differentiated from the variants running
+on-device with the `target_env = "sim"` cfg (or `target_abi = "sim"` before
+Rust CURRENT_RUSTC_VERSION).
+
+```rust
+if cfg!(all(target_vendor = "apple", target_env = "sim")) {
+    // Do something on the iOS/tvOS/visionOS/watchOS Simulator.
+} {
+    // Everything else, like Windows and non-Simulator iOS.
+}
+```
+
+This is similar to the `TARGET_OS_SIMULATOR` define in C code.
+
 ## Testing
 
 There is no support for running the Rust or standard library testsuite at the