diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa')
| -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_codegen_ssa/src/back/symbol_export.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/codegen_attrs.rs | 21 |
5 files changed, 101 insertions, 32 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_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs index 7e124f65324..0494666bda9 100644 --- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs +++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs @@ -569,7 +569,7 @@ fn symbol_export_level(tcx: TyCtxt<'_>, sym_def_id: DefId) -> SymbolExportLevel // core/std/allocators/etc. For example symbols used to hook up allocation // are not considered for export let codegen_fn_attrs = tcx.codegen_fn_attrs(sym_def_id); - let is_extern = codegen_fn_attrs.contains_extern_indicator(); + let is_extern = codegen_fn_attrs.contains_extern_indicator(tcx, sym_def_id); let std_internal = codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL); diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs index 7f54a47327a..287787eb3d1 100644 --- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs +++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs @@ -443,6 +443,27 @@ fn apply_overrides(tcx: TyCtxt<'_>, did: LocalDefId, codegen_fn_attrs: &mut Code if tcx.should_inherit_track_caller(did) { codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; } + + // Foreign items by default use no mangling for their symbol name. + if tcx.is_foreign_item(did) { + // There's a few exceptions to this rule though: + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) { + // * `#[rustc_std_internal_symbol]` mangles the symbol name in a special way + // both for exports and imports through foreign items. This is handled further, + // during symbol mangling logic. + } else if codegen_fn_attrs.link_name.is_some() { + // * This can be overridden with the `#[link_name]` attribute + } else { + // NOTE: there's one more exception that we cannot apply here. On wasm, + // some items cannot be `no_mangle`. + // However, we don't have enough information here to determine that. + // As such, no_mangle foreign items on wasm that have the same defid as some + // import will *still* be mangled despite this. + // + // if none of the exceptions apply; apply no_mangle + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE; + } + } } fn check_result( |