rustc_codegen_ssa::back::apple

Function xcrun_show_sdk_path

Source 
fn xcrun_show_sdk_path(
    sdk_name: &'static str,
    verbose: bool,
) -> Result<(PathBuf, String), XcrunError>
Expand description

Invoke xcrun --sdk $sdk_name --show-sdk-path to get the SDK path.

The exact logic that xcrun uses is unspecified (see man xcrun for a few details), and may change between macOS and Xcode versions, but it roughly boils down to finding the active developer directory, and then invoking xcodebuild -sdk $sdk_name -version to get the SDK details.

Finding the developer directory is roughly done by looking at, in order:

  • The DEVELOPER_DIR environment variable.
  • The /var/db/xcode_select_link symlink (set by xcode-select --switch).
  • /Applications/Xcode.app (hardcoded fallback path).
  • /Library/Developer/CommandLineTools (hardcoded fallback path).

Note that xcrun caches its result, but with a cold cache this whole operation can be quite slow, especially so the first time it’s run after a reboot.