diff options
| -rw-r--r-- | compiler/rustc_codegen_ssa/messages.ftl | 3 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/apple.rs | 24 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/link.rs | 83 | ||||
| -rw-r--r-- | compiler/rustc_target/src/spec/base/apple/mod.rs | 24 | ||||
| -rw-r--r-- | src/doc/unstable-book/src/compiler-environment-variables/SDKROOT.md | 2 | ||||
| -rw-r--r-- | tests/run-make/link-under-xcode/foo.rs | 1 | ||||
| -rw-r--r-- | tests/run-make/link-under-xcode/rmake.rs | 32 |
7 files changed, 115 insertions, 54 deletions
diff --git a/compiler/rustc_codegen_ssa/messages.ftl b/compiler/rustc_codegen_ssa/messages.ftl index 3ca070acc9d..b6cfea88363 100644 --- a/compiler/rustc_codegen_ssa/messages.ftl +++ b/compiler/rustc_codegen_ssa/messages.ftl @@ -401,6 +401,9 @@ codegen_ssa_version_script_write_failure = failed to write version script: {$err codegen_ssa_visual_studio_not_installed = you may need to install Visual Studio build tools with the "C++ build tools" workload +codegen_ssa_xcrun_about = + the SDK is needed by the linker to know where to find symbols in system libraries and for embedding the SDK version in the final object file + codegen_ssa_xcrun_command_line_tools_insufficient = when compiling for iOS, tvOS, visionOS or watchOS, you need a full installation of Xcode diff --git a/compiler/rustc_codegen_ssa/src/back/apple.rs b/compiler/rustc_codegen_ssa/src/back/apple.rs index 2f68bad1695..2274450e20e 100644 --- a/compiler/rustc_codegen_ssa/src/back/apple.rs +++ b/compiler/rustc_codegen_ssa/src/back/apple.rs @@ -160,6 +160,10 @@ pub(super) fn add_version_to_llvm_target( pub(super) fn get_sdk_root(sess: &Session) -> Option<PathBuf> { let sdk_name = sdk_name(&sess.target); + // Attempt to invoke `xcrun` to find the SDK. + // + // Note that when cross-compiling from e.g. Linux, the `xcrun` binary may sometimes be provided + // as a shim by a cross-compilation helper tool. It usually isn't, but we still try nonetheless. match xcrun_show_sdk_path(sdk_name, sess.verbose_internals()) { Ok((path, stderr)) => { // Emit extra stderr, such as if `-verbose` was passed, or if `xcrun` emitted a warning. @@ -169,7 +173,19 @@ pub(super) fn get_sdk_root(sess: &Session) -> Option<PathBuf> { Some(path) } Err(err) => { - let mut diag = sess.dcx().create_err(err); + // Failure to find the SDK is not a hard error, since the user might have specified it + // in a manner unknown to us (moreso if cross-compiling): + // - A compiler driver like `zig cc` which links using an internally bundled SDK. + // - Extra linker arguments (`-Clink-arg=-syslibroot`). + // - A custom linker or custom compiler driver. + // + // Though we still warn, since such cases are uncommon, and it is very hard to debug if + // you do not know the details. + // + // FIXME(madsmtm): Make this a lint, to allow deny warnings to work. + // (Or fix <https://github.com/rust-lang/rust/issues/21204>). + let mut diag = sess.dcx().create_warn(err); + diag.note(fluent::codegen_ssa_xcrun_about); // Recognize common error cases, and give more Rust-specific error messages for those. if let Some(developer_dir) = xcode_select_developer_dir() { @@ -209,6 +225,8 @@ fn xcrun_show_sdk_path( sdk_name: &'static str, verbose: bool, ) -> Result<(PathBuf, String), XcrunError> { + // Intentionally invoke the `xcrun` in PATH, since e.g. nixpkgs provide an `xcrun` shim, so we + // don't want to require `/usr/bin/xcrun`. let mut cmd = Command::new("xcrun"); if verbose { cmd.arg("--verbose"); @@ -280,7 +298,7 @@ fn stdout_to_path(mut stdout: Vec<u8>) -> PathBuf { } #[cfg(unix)] let path = <OsString as std::os::unix::ffi::OsStringExt>::from_vec(stdout); - #[cfg(not(unix))] // Unimportant, this is only used on macOS - let path = OsString::from(String::from_utf8(stdout).unwrap()); + #[cfg(not(unix))] // Not so important, this is mostly used on macOS + let path = OsString::from(String::from_utf8(stdout).expect("stdout must be UTF-8")); PathBuf::from(path) } diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs index 3ec0d900994..4ebe59dc2a7 100644 --- a/compiler/rustc_codegen_ssa/src/back/link.rs +++ b/compiler/rustc_codegen_ssa/src/back/link.rs @@ -3194,39 +3194,60 @@ fn add_apple_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavo } fn add_apple_sdk(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) -> Option<PathBuf> { - let os = &sess.target.os; - if sess.target.vendor != "apple" - || !matches!(os.as_ref(), "ios" | "tvos" | "watchos" | "visionos" | "macos") - || !matches!(flavor, LinkerFlavor::Darwin(..)) - { + if !sess.target.is_like_darwin { return None; } - - if os == "macos" && !matches!(flavor, LinkerFlavor::Darwin(Cc::No, _)) { + let LinkerFlavor::Darwin(cc, _) = flavor else { return None; - } - - let sdk_root = sess.time("get_apple_sdk_root", || get_apple_sdk_root(sess))?; + }; - match flavor { - LinkerFlavor::Darwin(Cc::Yes, _) => { - // Use `-isysroot` instead of `--sysroot`, as only the former - // makes Clang treat it as a platform SDK. - // - // This is admittedly a bit strange, as on most targets - // `-isysroot` only applies to include header files, but on Apple - // targets this also applies to libraries and frameworks. - cmd.cc_arg("-isysroot"); - cmd.cc_arg(&sdk_root); - } - LinkerFlavor::Darwin(Cc::No, _) => { - cmd.link_arg("-syslibroot"); - cmd.link_arg(&sdk_root); - } - _ => unreachable!(), + // The default compiler driver on macOS is at `/usr/bin/cc`. This is a trampoline binary that + // effectively invokes `xcrun cc` internally to look up both the compiler binary and the SDK + // root from the current Xcode installation. When cross-compiling, when `rustc` is invoked + // inside Xcode, or when invoking the linker directly, this default logic is unsuitable, so + // instead we invoke `xcrun` manually. + // + // (Note that this doesn't mean we get a duplicate lookup here - passing `SDKROOT` below will + // cause the trampoline binary to skip looking up the SDK itself). + let sdkroot = sess.time("get_apple_sdk_root", || get_apple_sdk_root(sess))?; + + if cc == Cc::Yes { + // There are a few options to pass the SDK root when linking with a C/C++ compiler: + // - The `--sysroot` flag. + // - The `-isysroot` flag. + // - The `SDKROOT` environment variable. + // + // `--sysroot` isn't actually enough to get Clang to treat it as a platform SDK, you need + // to specify `-isysroot`. This is admittedly a bit strange, as on most targets `-isysroot` + // only applies to include header files, but on Apple targets it also applies to libraries + // and frameworks. + // + // This leaves the choice between `-isysroot` and `SDKROOT`. Both are supported by Clang and + // GCC, though they may not be supported by all compiler drivers. We choose `SDKROOT`, + // primarily because that is the same interface that is used when invoking the tool under + // `xcrun -sdk macosx $tool`. + // + // In that sense, if a given compiler driver does not support `SDKROOT`, the blame is fairly + // clearly in the tool in question, since they also don't support being run under `xcrun`. + // + // Additionally, `SDKROOT` is an environment variable and thus optional. It also has lower + // precedence than `-isysroot`, so a custom compiler driver that does not support it and + // instead figures out the SDK on their own can easily do so by using `-isysroot`. + // + // (This in particular affects Clang built with the `DEFAULT_SYSROOT` CMake flag, such as + // the one provided by some versions of Homebrew's `llvm` package. Those will end up + // ignoring the value we set here, and instead use their built-in sysroot). + cmd.cmd().env("SDKROOT", &sdkroot); + } else { + // When invoking the linker directly, we use the `-syslibroot` parameter. `SDKROOT` is not + // read by the linker, so it's really the only option. + // + // This is also what Clang does. + cmd.link_arg("-syslibroot"); + cmd.link_arg(&sdkroot); } - Some(sdk_root) + Some(sdkroot) } fn get_apple_sdk_root(sess: &Session) -> Option<PathBuf> { @@ -3255,7 +3276,13 @@ fn get_apple_sdk_root(sess: &Session) -> Option<PathBuf> { } "macosx" if sdkroot.contains("iPhoneOS.platform") - || sdkroot.contains("iPhoneSimulator.platform") => {} + || sdkroot.contains("iPhoneSimulator.platform") + || sdkroot.contains("AppleTVOS.platform") + || sdkroot.contains("AppleTVSimulator.platform") + || sdkroot.contains("WatchOS.platform") + || sdkroot.contains("WatchSimulator.platform") + || sdkroot.contains("XROS.platform") + || sdkroot.contains("XRSimulator.platform") => {} "watchos" if sdkroot.contains("WatchSimulator.platform") || sdkroot.contains("MacOSX.platform") => {} diff --git a/compiler/rustc_target/src/spec/base/apple/mod.rs b/compiler/rustc_target/src/spec/base/apple/mod.rs index da9f96ce37d..ecc74264160 100644 --- a/compiler/rustc_target/src/spec/base/apple/mod.rs +++ b/compiler/rustc_target/src/spec/base/apple/mod.rs @@ -1,5 +1,4 @@ use std::borrow::Cow; -use std::env; use std::fmt::{Display, from_fn}; use std::num::ParseIntError; use std::str::FromStr; @@ -209,29 +208,10 @@ fn link_env_remove(os: &'static str) -> StaticCow<[StaticCow<str>]> { // that's only applicable to cross-OS compilation. Always leave anything for the // host OS alone though. if os == "macos" { - let mut env_remove = Vec::with_capacity(2); - // Remove the `SDKROOT` environment variable if it's clearly set for the wrong platform, which - // may occur when we're linking a custom build script while targeting iOS for example. - if let Ok(sdkroot) = env::var("SDKROOT") { - if sdkroot.contains("iPhoneOS.platform") - || sdkroot.contains("iPhoneSimulator.platform") - || sdkroot.contains("AppleTVOS.platform") - || sdkroot.contains("AppleTVSimulator.platform") - || sdkroot.contains("WatchOS.platform") - || sdkroot.contains("WatchSimulator.platform") - || sdkroot.contains("XROS.platform") - || sdkroot.contains("XRSimulator.platform") - { - env_remove.push("SDKROOT".into()) - } - } - // Additionally, `IPHONEOS_DEPLOYMENT_TARGET` must not be set when using the Xcode linker at + // `IPHONEOS_DEPLOYMENT_TARGET` must not be set when using the Xcode linker at // "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld", // although this is apparently ignored when using the linker at "/usr/bin/ld". - env_remove.push("IPHONEOS_DEPLOYMENT_TARGET".into()); - env_remove.push("TVOS_DEPLOYMENT_TARGET".into()); - env_remove.push("XROS_DEPLOYMENT_TARGET".into()); - env_remove.into() + cvs!["IPHONEOS_DEPLOYMENT_TARGET", "TVOS_DEPLOYMENT_TARGET", "XROS_DEPLOYMENT_TARGET"] } else { // Otherwise if cross-compiling for a different OS/SDK (including Mac Catalyst), remove any part // of the linking environment that's wrong and reversed. diff --git a/src/doc/unstable-book/src/compiler-environment-variables/SDKROOT.md b/src/doc/unstable-book/src/compiler-environment-variables/SDKROOT.md index be9ed02f54d..6d371ae289f 100644 --- a/src/doc/unstable-book/src/compiler-environment-variables/SDKROOT.md +++ b/src/doc/unstable-book/src/compiler-environment-variables/SDKROOT.md @@ -1,6 +1,6 @@ # `SDKROOT` This environment variable is used on Apple targets. -It is passed through to the linker (currently either as `-isysroot` or `-syslibroot`). +It is passed through to the linker (currently either directly or via the `-syslibroot` flag). Note that this variable is not always respected. When the SDKROOT is clearly wrong (e.g. when the platform of the SDK does not match the `--target` used by rustc), this is ignored and rustc does its own detection. diff --git a/tests/run-make/link-under-xcode/foo.rs b/tests/run-make/link-under-xcode/foo.rs new file mode 100644 index 00000000000..f328e4d9d04 --- /dev/null +++ b/tests/run-make/link-under-xcode/foo.rs @@ -0,0 +1 @@ +fn main() {} diff --git a/tests/run-make/link-under-xcode/rmake.rs b/tests/run-make/link-under-xcode/rmake.rs new file mode 100644 index 00000000000..c9394feb000 --- /dev/null +++ b/tests/run-make/link-under-xcode/rmake.rs @@ -0,0 +1,32 @@ +//! Test that linking works under an environment similar to what Xcode sets up. +//! +//! Regression test for https://github.com/rust-lang/rust/issues/80817. + +//@ only-apple + +use run_make_support::{cmd, rustc, target}; + +fn main() { + // Fetch toolchain `/usr/bin` directory. Usually: + // /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin + let clang_bin = cmd("xcrun").arg("--find").arg("clang").run().stdout_utf8(); + let toolchain_bin = clang_bin.trim().strip_suffix("/clang").unwrap(); + + // Put toolchain directory at the front of PATH. + let path = format!("{}:{}", toolchain_bin, std::env::var("PATH").unwrap()); + + // Check that compiling and linking still works. + // + // Removing `SDKROOT` is necessary for the test to excercise what we want, since bootstrap runs + // under `/usr/bin/python3`, which will set SDKROOT for us. + rustc().target(target()).env_remove("SDKROOT").env("PATH", &path).input("foo.rs").run(); + + // Also check linking directly with the system linker. + rustc() + .target(target()) + .env_remove("SDKROOT") + .env("PATH", &path) + .input("foo.rs") + .arg("-Clinker-flavor=ld") + .run(); +} |