Rollup merge of #136767 - onur-ozkan:is-host-target, r=albertlarsan68,jieyouxu

improve host/cross target checking

Using an invalid equality operator on `builder.config.build !=/==` can be hard to detect in reviews (which is quite dangerous). Replaced them with `is_host_target`, which is much clearer as it explicitly states what it does.

Author: GuillaumeGomez

src/bootstrap/src/core/build_steps/compile.rs

@@ -191,7 +191,7 @@ impl Step for Std {
         // The LLD wrappers and `rust-lld` are self-contained linking components that can be
         // necessary to link the stdlib on some targets. We'll also need to copy these binaries to
         // the `stage0-sysroot` to ensure the linker is found when bootstrapping on such a target.
-        if compiler.stage == 0 && compiler.host == builder.config.build {
+        if compiler.stage == 0 && builder.is_builder_target(&compiler.host) {
             // We want to copy the host `bin` folder within the `rustlib` folder in the sysroot.
             let src_sysroot_bin = builder
                 .rustc_snapshot_sysroot()
@@ -2310,7 +2310,8 @@ pub fn strip_debug(builder: &Builder<'_>, target: TargetSelection, path: &Path)
     // FIXME: to make things simpler for now, limit this to the host and target where we know
     // `strip -g` is both available and will fix the issue, i.e. on a x64 linux host that is not
     // cross-compiling. Expand this to other appropriate targets in the future.
-    if target != "x86_64-unknown-linux-gnu" || target != builder.config.build || !path.exists() {
+    if target != "x86_64-unknown-linux-gnu" || !builder.is_builder_target(&target) || !path.exists()
+    {
         return;
     }
 

src/bootstrap/src/core/build_steps/dist.rs

@@ -582,7 +582,7 @@ impl Step for DebuggerScripts {
 fn skip_host_target_lib(builder: &Builder<'_>, compiler: Compiler) -> bool {
     // The only true set of target libraries came from the build triple, so
     // let's reduce redundant work by only producing archives from that host.
-    if compiler.host != builder.config.build {
+    if !builder.is_builder_target(&compiler.host) {
         builder.info("\tskipping, not a build host");
         true
     } else {
@@ -637,7 +637,7 @@ fn copy_target_libs(
     for (path, dependency_type) in builder.read_stamp_file(stamp) {
         if dependency_type == DependencyType::TargetSelfContained {
             builder.copy_link(&path, &self_contained_dst.join(path.file_name().unwrap()));
-        } else if dependency_type == DependencyType::Target || builder.config.build == target {
+        } else if dependency_type == DependencyType::Target || builder.is_builder_target(&target) {
             builder.copy_link(&path, &dst.join(path.file_name().unwrap()));
         }
     }
@@ -786,7 +786,7 @@ impl Step for Analysis {
     fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
         let compiler = self.compiler;
         let target = self.target;
-        if compiler.host != builder.config.build {
+        if !builder.is_builder_target(&compiler.host) {
             return None;
         }
 

src/bootstrap/src/core/build_steps/llvm.rs

@@ -516,7 +516,7 @@ impl Step for Llvm {
         }
 
         // https://llvm.org/docs/HowToCrossCompileLLVM.html
-        if target != builder.config.build {
+        if !builder.is_builder_target(&target) {
             let LlvmResult { llvm_config, .. } =
                 builder.ensure(Llvm { target: builder.config.build });
             if !builder.config.dry_run() {
@@ -661,7 +661,7 @@ fn configure_cmake(
     }
     cfg.target(&target.triple).host(&builder.config.build.triple);
 
-    if target != builder.config.build {
+    if !builder.is_builder_target(&target) {
         cfg.define("CMAKE_CROSSCOMPILING", "True");
 
         if target.contains("netbsd") {
@@ -1111,7 +1111,7 @@ impl Step for Lld {
             .define("LLVM_CMAKE_DIR", llvm_cmake_dir)
             .define("LLVM_INCLUDE_TESTS", "OFF");
 
-        if target != builder.config.build {
+        if !builder.is_builder_target(&target) {
             // Use the host llvm-tblgen binary.
             cfg.define(
                 "LLVM_TABLEGEN_EXE",

src/bootstrap/src/core/build_steps/test.rs

@@ -2742,7 +2742,7 @@ impl Step for Crate {
             cargo
         } else {
             // Also prepare a sysroot for the target.
-            if builder.config.build != target {
+            if !builder.is_builder_target(&target) {
                 builder.ensure(compile::Std::new(compiler, target).force_recompile(true));
                 builder.ensure(RemoteCopyLibs { compiler, target });
             }

src/bootstrap/src/core/builder/tests.rs

@@ -1065,3 +1065,19 @@ fn test_prebuilt_llvm_config_path_resolution() {
         .join(exe("llvm-config", builder.config.build));
     assert_eq!(expected, actual);
 }
+
+#[test]
+fn test_is_builder_target() {
+    let target1 = TargetSelection::from_user(TEST_TRIPLE_1);
+    let target2 = TargetSelection::from_user(TEST_TRIPLE_2);
+
+    for (target1, target2) in [(target1, target2), (target2, target1)] {
+        let mut config = configure("build", &[], &[]);
+        config.build = target1;
+        let build = Build::new(config);
+        let builder = Builder::new(&build);
+
+        assert!(builder.is_builder_target(&target1));
+        assert!(!builder.is_builder_target(&target2));
+    }
+}

src/bootstrap/src/core/sanity.rs

@@ -329,7 +329,7 @@ than building it.
         if target.contains("musl") && !target.contains("unikraft") {
             // If this is a native target (host is also musl) and no musl-root is given,
             // fall back to the system toolchain in /usr before giving up
-            if build.musl_root(*target).is_none() && build.config.build == *target {
+            if build.musl_root(*target).is_none() && build.is_builder_target(target) {
                 let target = build.config.target_config.entry(*target).or_default();
                 target.musl_root = Some("/usr".into());
             }

src/bootstrap/src/lib.rs

@@ -739,7 +739,7 @@ impl Build {
     /// Note that if LLVM is configured externally then the directory returned
     /// will likely be empty.
     fn llvm_out(&self, target: TargetSelection) -> PathBuf {
-        if self.config.llvm_from_ci && self.config.build == target {
+        if self.config.llvm_from_ci && self.is_builder_target(&target) {
             self.config.ci_llvm_root()
         } else {
             self.out.join(target).join("llvm")
@@ -789,7 +789,7 @@ impl Build {
     fn is_system_llvm(&self, target: TargetSelection) -> bool {
         match self.config.target_config.get(&target) {
             Some(Target { llvm_config: Some(_), .. }) => {
-                let ci_llvm = self.config.llvm_from_ci && target == self.config.build;
+                let ci_llvm = self.config.llvm_from_ci && self.is_builder_target(&target);
                 !ci_llvm
             }
             // We're building from the in-tree src/llvm-project sources.
@@ -1274,7 +1274,7 @@ Executed at: {executed_at}"#,
             // need to use CXX compiler as linker to resolve the exception functions
             // that are only existed in CXX libraries
             Some(self.cxx.borrow()[&target].path().into())
-        } else if target != self.config.build
+        } else if !self.is_builder_target(&target)
             && helpers::use_host_linker(target)
             && !target.is_msvc()
         {
@@ -1925,6 +1925,11 @@ to download LLVM rather than building it.
         stream.reset().unwrap();
         result
     }
+
+    /// Checks if the given target is the same as the builder target.
+    fn is_builder_target(&self, target: &TargetSelection) -> bool {
+        &self.config.build == target
+    }
 }
 
 #[cfg(unix)]