diff --git a/src/bootstrap/src/core/build_steps/check.rs b/src/bootstrap/src/core/build_steps/check.rs
index 911a51b0e161b..f47873590a17b 100644
--- a/src/bootstrap/src/core/build_steps/check.rs
+++ b/src/bootstrap/src/core/build_steps/check.rs
@@ -89,7 +89,7 @@ impl Step for Std {
         let stage = self.custom_stage.unwrap_or(builder.top_stage);
 
         let target = self.target;
-        let compiler = builder.compiler(stage, builder.config.build);
+        let compiler = builder.compiler(stage, builder.config.host_target);
 
         if stage == 0 {
             let mut is_explicitly_called =
@@ -244,7 +244,7 @@ impl Step for Rustc {
     /// the `compiler` targeting the `target` architecture. The artifacts
     /// created will also be linked into the sysroot directory.
     fn run(self, builder: &Builder<'_>) {
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
         let target = self.target;
 
         if compiler.stage != 0 {
@@ -327,7 +327,7 @@ impl Step for CodegenBackend {
             return;
         }
 
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
         let target = self.target;
         let backend = self.backend;
 
@@ -382,7 +382,7 @@ impl Step for RustAnalyzer {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
         let target = self.target;
 
         builder.ensure(Rustc::new(target, builder));
@@ -448,7 +448,7 @@ impl Step for Compiletest {
 
         let compiler = builder.compiler(
             if mode == Mode::ToolBootstrap { 0 } else { builder.top_stage },
-            builder.config.build,
+            builder.config.host_target,
         );
 
         if mode != Mode::ToolBootstrap {
@@ -527,7 +527,7 @@ fn run_tool_check_step(
     path: &str,
 ) {
     let display_name = path.rsplit('/').next().unwrap();
-    let compiler = builder.compiler(builder.top_stage, builder.config.build);
+    let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
 
     builder.ensure(Rustc::new(target, builder));
 
@@ -614,7 +614,7 @@ impl Step for CoverageDump {
         // Make sure we haven't forgotten any fields, if there are any.
         let Self {} = self;
         let display_name = "coverage-dump";
-        let host = builder.config.build;
+        let host = builder.config.host_target;
         let target = host;
         let mode = Mode::ToolBootstrap;
 
diff --git a/src/bootstrap/src/core/build_steps/clippy.rs b/src/bootstrap/src/core/build_steps/clippy.rs
index 0652c08ff496e..788a3b9601d9d 100644
--- a/src/bootstrap/src/core/build_steps/clippy.rs
+++ b/src/bootstrap/src/core/build_steps/clippy.rs
@@ -144,7 +144,7 @@ impl Step for Std {
         builder.require_submodule("library/stdarch", None);
 
         let target = self.target;
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
 
         let mut cargo = builder::Cargo::new(
             builder,
@@ -204,7 +204,7 @@ impl Step for Rustc {
     /// This will lint the compiler for a particular stage of the build using
     /// the `compiler` targeting the `target` architecture.
     fn run(self, builder: &Builder<'_>) {
-        let compiler = builder.compiler(builder.top_stage, builder.config.build);
+        let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
         let target = self.target;
 
         if !builder.download_rustc() {
@@ -285,7 +285,7 @@ macro_rules! lint_any {
             }
 
             fn run(self, builder: &Builder<'_>) -> Self::Output {
-                let compiler = builder.compiler(builder.top_stage, builder.config.build);
+                let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
                 let target = self.target;
 
                 if !builder.download_rustc() {
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index 5ecce31fe1562..560925abba6a9 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -35,6 +35,7 @@ use crate::utils::helpers::{
 };
 use crate::{CLang, Compiler, DependencyType, FileType, GitRepo, LLVM_TOOLS, Mode, debug, trace};
 
+/// Build a standard library for the given `target` using the given `compiler`.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Std {
     pub target: TargetSelection,
@@ -159,7 +160,7 @@ impl Step for Std {
         let compiler = if builder.download_rustc() && self.force_recompile {
             // When there are changes in the library tree with CI-rustc, we want to build
             // the stageN library and that requires using stageN-1 compiler.
-            builder.compiler(self.compiler.stage.saturating_sub(1), builder.config.build)
+            builder.compiler(self.compiler.stage.saturating_sub(1), builder.config.host_target)
         } else {
             self.compiler
         };
@@ -301,7 +302,7 @@ impl Step for Std {
 
         builder.ensure(StdLink::from_std(
             self,
-            builder.compiler(compiler.stage, builder.config.build),
+            builder.compiler(compiler.stage, builder.config.host_target),
         ));
     }
 }
@@ -960,11 +961,18 @@ fn cp_rustc_component_to_ci_sysroot(builder: &Builder<'_>, sysroot: &Path, conte
     }
 }
 
+/// Build rustc using the passed `build_compiler`.
+///
+/// - Makes sure that `build_compiler` has a standard library prepared for its host target,
+///   so that it can compile build scripts and proc macros when building this `rustc`.
+/// - Makes sure that `build_compiler` has a standard library prepared for `target`,
+///   so that the built `rustc` can *link to it* and use it at runtime.
 #[derive(Debug, PartialOrd, Ord, Clone, PartialEq, Eq, Hash)]
 pub struct Rustc {
+    /// The target on which rustc will run (its host).
     pub target: TargetSelection,
-    /// The **previous** compiler used to compile this compiler.
-    pub compiler: Compiler,
+    /// The **previous** compiler used to compile this rustc.
+    pub build_compiler: Compiler,
     /// Whether to build a subset of crates, rather than the whole compiler.
     ///
     /// This should only be requested by the user, not used within bootstrap itself.
@@ -974,8 +982,8 @@ pub struct Rustc {
 }
 
 impl Rustc {
-    pub fn new(compiler: Compiler, target: TargetSelection) -> Self {
-        Self { target, compiler, crates: Default::default() }
+    pub fn new(build_compiler: Compiler, target: TargetSelection) -> Self {
+        Self { target, build_compiler, crates: Default::default() }
     }
 }
 
@@ -1007,7 +1015,7 @@ impl Step for Rustc {
     fn make_run(run: RunConfig<'_>) {
         let crates = run.cargo_crates_in_set();
         run.builder.ensure(Rustc {
-            compiler: run
+            build_compiler: run
                 .builder
                 .compiler(run.builder.top_stage.saturating_sub(1), run.build_triple()),
             target: run.target,
@@ -1018,7 +1026,7 @@ impl Step for Rustc {
     /// Builds the compiler.
     ///
     /// This will build the compiler for a particular stage of the build using
-    /// the `compiler` targeting the `target` architecture. The artifacts
+    /// the `build_compiler` targeting the `target` architecture. The artifacts
     /// created will also be linked into the sysroot directory.
     #[cfg_attr(
         feature = "tracing",
@@ -1026,54 +1034,58 @@ impl Step for Rustc {
             level = "debug",
             name = "Rustc::run",
             skip_all,
-            fields(previous_compiler = ?self.compiler, target = ?self.target),
+            fields(previous_compiler = ?self.build_compiler, target = ?self.target),
         ),
     )]
     fn run(self, builder: &Builder<'_>) -> u32 {
-        let compiler = self.compiler;
+        let build_compiler = self.build_compiler;
         let target = self.target;
 
         // NOTE: the ABI of the stage0 compiler is different from the ABI of the downloaded compiler,
         // so its artifacts can't be reused.
-        if builder.download_rustc() && compiler.stage != 0 {
-            trace!(stage = compiler.stage, "`download_rustc` requested");
+        if builder.download_rustc() && build_compiler.stage != 0 {
+            trace!(stage = build_compiler.stage, "`download_rustc` requested");
 
-            let sysroot = builder.ensure(Sysroot { compiler, force_recompile: false });
+            let sysroot =
+                builder.ensure(Sysroot { compiler: build_compiler, force_recompile: false });
             cp_rustc_component_to_ci_sysroot(
                 builder,
                 &sysroot,
                 builder.config.ci_rustc_dev_contents(),
             );
-            return compiler.stage;
+            return build_compiler.stage;
         }
 
-        builder.ensure(Std::new(compiler, target));
+        // Build a standard library for `target` using the `build_compiler`.
+        // This will be the standard library that the rustc which we build *links to*.
+        builder.ensure(Std::new(build_compiler, target));
 
-        if builder.config.keep_stage.contains(&compiler.stage) {
-            trace!(stage = compiler.stage, "`keep-stage` requested");
+        if builder.config.keep_stage.contains(&build_compiler.stage) {
+            trace!(stage = build_compiler.stage, "`keep-stage` requested");
 
             builder.info("WARNING: Using a potentially old librustc. This may not behave well.");
             builder.info("WARNING: Use `--keep-stage-std` if you want to rebuild the compiler when it changes");
-            builder.ensure(RustcLink::from_rustc(self, compiler));
+            builder.ensure(RustcLink::from_rustc(self, build_compiler));
 
-            return compiler.stage;
+            return build_compiler.stage;
         }
 
-        let compiler_to_use = builder.compiler_for(compiler.stage, compiler.host, target);
-        if compiler_to_use != compiler {
+        let compiler_to_use =
+            builder.compiler_for(build_compiler.stage, build_compiler.host, target);
+        if compiler_to_use != build_compiler {
             builder.ensure(Rustc::new(compiler_to_use, target));
             let msg = if compiler_to_use.host == target {
                 format!(
                     "Uplifting rustc (stage{} -> stage{})",
                     compiler_to_use.stage,
-                    compiler.stage + 1
+                    build_compiler.stage + 1
                 )
             } else {
                 format!(
                     "Uplifting rustc (stage{}:{} -> stage{}:{})",
                     compiler_to_use.stage,
                     compiler_to_use.host,
-                    compiler.stage + 1,
+                    build_compiler.stage + 1,
                     target
                 )
             };
@@ -1082,22 +1094,26 @@ impl Step for Rustc {
             return compiler_to_use.stage;
         }
 
-        // Ensure that build scripts and proc macros have a std / libproc_macro to link against.
+        // Build a standard library for the current host target using the `build_compiler`.
+        // This standard library will be used when building `rustc` for compiling
+        // build scripts and proc macros.
+        // If we are not cross-compiling, the Std build above will be the same one as the one we
+        // prepare here.
         builder.ensure(Std::new(
-            builder.compiler(self.compiler.stage, builder.config.build),
-            builder.config.build,
+            builder.compiler(self.build_compiler.stage, builder.config.host_target),
+            builder.config.host_target,
         ));
 
         let mut cargo = builder::Cargo::new(
             builder,
-            compiler,
+            build_compiler,
             Mode::Rustc,
             SourceType::InTree,
             target,
             Kind::Build,
         );
 
-        rustc_cargo(builder, &mut cargo, target, &compiler, &self.crates);
+        rustc_cargo(builder, &mut cargo, target, &build_compiler, &self.crates);
 
         // NB: all RUSTFLAGS should be added to `rustc_cargo()` so they will be
         // consistently applied by check/doc/test modes too.
@@ -1106,19 +1122,19 @@ impl Step for Rustc {
             cargo.arg("-p").arg(krate);
         }
 
-        if builder.build.config.enable_bolt_settings && compiler.stage == 1 {
+        if builder.build.config.enable_bolt_settings && build_compiler.stage == 1 {
             // Relocations are required for BOLT to work.
             cargo.env("RUSTC_BOLT_LINK_FLAGS", "1");
         }
 
         let _guard = builder.msg_sysroot_tool(
             Kind::Build,
-            compiler.stage,
+            build_compiler.stage,
             format_args!("compiler artifacts{}", crate_description(&self.crates)),
-            compiler.host,
+            build_compiler.host,
             target,
         );
-        let stamp = build_stamp::librustc_stamp(builder, compiler, target);
+        let stamp = build_stamp::librustc_stamp(builder, build_compiler, target);
         run_cargo(
             builder,
             cargo,
@@ -1150,10 +1166,10 @@ impl Step for Rustc {
 
         builder.ensure(RustcLink::from_rustc(
             self,
-            builder.compiler(compiler.stage, builder.config.build),
+            builder.compiler(build_compiler.stage, builder.config.host_target),
         ));
 
-        compiler.stage
+        build_compiler.stage
     }
 }
 
@@ -1161,7 +1177,7 @@ pub fn rustc_cargo(
     builder: &Builder<'_>,
     cargo: &mut Cargo,
     target: TargetSelection,
-    compiler: &Compiler,
+    build_compiler: &Compiler,
     crates: &[String],
 ) {
     cargo
@@ -1190,11 +1206,11 @@ pub fn rustc_cargo(
     // We want to link against registerEnzyme and in the future we want to use additional
     // functionality from Enzyme core. For that we need to link against Enzyme.
     if builder.config.llvm_enzyme {
-        let arch = builder.build.build;
+        let arch = builder.build.host_target;
         let enzyme_dir = builder.build.out.join(arch).join("enzyme").join("lib");
         cargo.rustflag("-L").rustflag(enzyme_dir.to_str().expect("Invalid path"));
 
-        if let Some(llvm_config) = builder.llvm_config(builder.config.build) {
+        if let Some(llvm_config) = builder.llvm_config(builder.config.host_target) {
             let llvm_version_major = llvm::get_llvm_version_major(builder, &llvm_config);
             cargo.rustflag("-l").rustflag(&format!("Enzyme-{llvm_version_major}"));
         }
@@ -1208,7 +1224,7 @@ pub fn rustc_cargo(
         cargo.rustflag("-Zdefault-visibility=protected");
     }
 
-    if is_lto_stage(compiler) {
+    if is_lto_stage(build_compiler) {
         match builder.config.rust_lto {
             RustcLto::Thin | RustcLto::Fat => {
                 // Since using LTO for optimizing dylibs is currently experimental,
@@ -1241,7 +1257,7 @@ pub fn rustc_cargo(
     // is already on by default in MSVC optimized builds, which is interpreted as --icf=all:
     // https://github.com/llvm/llvm-project/blob/3329cec2f79185bafd678f310fafadba2a8c76d2/lld/COFF/Driver.cpp#L1746
     // https://github.com/rust-lang/rust/blob/f22819bcce4abaff7d1246a56eec493418f9f4ee/compiler/rustc_codegen_ssa/src/back/linker.rs#L827
-    if builder.config.lld_mode.is_used() && !compiler.host.is_msvc() {
+    if builder.config.lld_mode.is_used() && !build_compiler.host.is_msvc() {
         cargo.rustflag("-Clink-args=-Wl,--icf=all");
     }
 
@@ -1249,7 +1265,7 @@ pub fn rustc_cargo(
         panic!("Cannot use and generate PGO profiles at the same time");
     }
     let is_collecting = if let Some(path) = &builder.config.rust_profile_generate {
-        if compiler.stage == 1 {
+        if build_compiler.stage == 1 {
             cargo.rustflag(&format!("-Cprofile-generate={path}"));
             // Apparently necessary to avoid overflowing the counters during
             // a Cargo build profile
@@ -1259,7 +1275,7 @@ pub fn rustc_cargo(
             false
         }
     } else if let Some(path) = &builder.config.rust_profile_use {
-        if compiler.stage == 1 {
+        if build_compiler.stage == 1 {
             cargo.rustflag(&format!("-Cprofile-use={path}"));
             if builder.is_verbose() {
                 cargo.rustflag("-Cllvm-args=-pgo-warn-missing-function");
@@ -1284,20 +1300,20 @@ pub fn rustc_cargo(
     // useful.
     // This is only performed for non-incremental builds, as ccache cannot deal with these.
     if let Some(ref ccache) = builder.config.ccache
-        && compiler.stage == 0
+        && build_compiler.stage == 0
         && !builder.config.incremental
     {
         cargo.env("RUSTC_WRAPPER", ccache);
     }
 
-    rustc_cargo_env(builder, cargo, target, compiler.stage);
+    rustc_cargo_env(builder, cargo, target, build_compiler.stage);
 }
 
 pub fn rustc_cargo_env(
     builder: &Builder<'_>,
     cargo: &mut Cargo,
     target: TargetSelection,
-    stage: u32,
+    build_stage: u32,
 ) {
     // Set some configuration variables picked up by build scripts and
     // the compiler alike
@@ -1364,7 +1380,7 @@ pub fn rustc_cargo_env(
             crate::core::build_steps::llvm::prebuilt_llvm_config(builder, target, false)
                 .should_build();
         // `top_stage == stage` might be false for `check --stage 1`, if we are building the stage 1 compiler
-        let can_skip_build = builder.kind == Kind::Check && builder.top_stage == stage;
+        let can_skip_build = builder.kind == Kind::Check && builder.top_stage == build_stage;
         let should_skip_build = building_is_expensive && can_skip_build;
         if !should_skip_build {
             rustc_llvm_env(builder, cargo, target)
@@ -1475,7 +1491,7 @@ impl RustcLink {
     fn from_rustc(rustc: Rustc, host_compiler: Compiler) -> Self {
         Self {
             compiler: host_compiler,
-            previous_stage_compiler: rustc.compiler,
+            previous_stage_compiler: rustc.build_compiler,
             target: rustc.target,
             crates: rustc.crates,
         }
@@ -1813,7 +1829,7 @@ impl Step for Sysroot {
         // If we're downloading a compiler from CI, we can use the same compiler for all stages other than 0.
         if builder.download_rustc() && compiler.stage != 0 {
             assert_eq!(
-                builder.config.build, compiler.host,
+                builder.config.host_target, compiler.host,
                 "Cross-compiling is not yet supported with `download-rustc`",
             );
 
@@ -1967,7 +1983,7 @@ impl Step for Assemble {
         if target_compiler.stage == 0 {
             trace!("stage 0 build compiler is always available, simply returning");
             assert_eq!(
-                builder.config.build, target_compiler.host,
+                builder.config.host_target, target_compiler.host,
                 "Cannot obtain compiler for non-native build triple at stage 0"
             );
             // The stage 0 compiler for the build triple is always pre-built.
@@ -2080,15 +2096,16 @@ impl Step for Assemble {
         debug!(
             "ensuring build compiler is available: compiler(stage = {}, host = {:?})",
             target_compiler.stage - 1,
-            builder.config.build,
+            builder.config.host_target,
         );
-        let mut build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
+        let mut build_compiler =
+            builder.compiler(target_compiler.stage - 1, builder.config.host_target);
 
         // Build enzyme
         if builder.config.llvm_enzyme && !builder.config.dry_run() {
             debug!("`llvm_enzyme` requested");
             let enzyme_install = builder.ensure(llvm::Enzyme { target: build_compiler.host });
-            let llvm_config = builder.llvm_config(builder.config.build).unwrap();
+            let llvm_config = builder.llvm_config(builder.config.host_target).unwrap();
             let llvm_version_major = llvm::get_llvm_version_major(builder, &llvm_config);
             let lib_ext = std::env::consts::DLL_EXTENSION;
             let libenzyme = format!("libEnzyme-{llvm_version_major}");
diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
index 587fca8037469..4ee7f691a43c8 100644
--- a/src/bootstrap/src/core/build_steps/dist.rs
+++ b/src/bootstrap/src/core/build_steps/dist.rs
@@ -422,7 +422,7 @@ impl Step for Rustc {
             }
 
             let ra_proc_macro_srv_compiler =
-                builder.compiler_for(compiler.stage, builder.config.build, compiler.host);
+                builder.compiler_for(compiler.stage, builder.config.host_target, compiler.host);
             builder.ensure(compile::Rustc::new(ra_proc_macro_srv_compiler, compiler.host));
 
             if let Some(ra_proc_macro_srv) = builder.ensure_if_default(
@@ -696,7 +696,7 @@ impl Step for Std {
         run.builder.ensure(Std {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -748,7 +748,7 @@ impl Step for RustcDev {
         run.builder.ensure(RustcDev {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -815,7 +815,7 @@ impl Step for Analysis {
             // through the sysroot uplifting.
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -1168,7 +1168,7 @@ impl Step for Cargo {
         run.builder.ensure(Cargo {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -1224,7 +1224,7 @@ impl Step for RustAnalyzer {
         run.builder.ensure(RustAnalyzer {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -1268,7 +1268,7 @@ impl Step for Clippy {
         run.builder.ensure(Clippy {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -1317,7 +1317,7 @@ impl Step for Miri {
         run.builder.ensure(Miri {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -1462,7 +1462,7 @@ impl Step for Rustfmt {
         run.builder.ensure(Rustfmt {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
@@ -1507,7 +1507,7 @@ impl Step for Extended {
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Extended {
             stage: run.builder.top_stage,
-            host: run.builder.config.build,
+            host: run.builder.config.host_target,
             target: run.target,
         });
     }
@@ -2156,7 +2156,7 @@ fn maybe_install_llvm(
         cmd.arg("--libfiles");
         builder.verbose(|| println!("running {cmd:?}"));
         let files = cmd.run_capture_stdout(builder).stdout();
-        let build_llvm_out = &builder.llvm_out(builder.config.build);
+        let build_llvm_out = &builder.llvm_out(builder.config.host_target);
         let target_llvm_out = &builder.llvm_out(target);
         for file in files.trim_end().split(' ') {
             // If we're not using a custom LLVM, make sure we package for the target.
@@ -2340,7 +2340,7 @@ impl Step for LlvmBitcodeLinker {
         run.builder.ensure(LlvmBitcodeLinker {
             compiler: run.builder.compiler_for(
                 run.builder.top_stage,
-                run.builder.config.build,
+                run.builder.config.host_target,
                 run.target,
             ),
             target: run.target,
diff --git a/src/bootstrap/src/core/build_steps/doc.rs b/src/bootstrap/src/core/build_steps/doc.rs
index 7fccf85a0ea9f..215c155651a23 100644
--- a/src/bootstrap/src/core/build_steps/doc.rs
+++ b/src/bootstrap/src/core/build_steps/doc.rs
@@ -209,7 +209,7 @@ impl Step for TheBook {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(TheBook {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -329,7 +329,7 @@ impl Step for Standalone {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Standalone {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -431,7 +431,7 @@ impl Step for Releases {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Releases {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -449,7 +449,7 @@ impl Step for Releases {
         t!(fs::create_dir_all(&out));
 
         builder.ensure(Standalone {
-            compiler: builder.compiler(builder.top_stage, builder.config.build),
+            compiler: builder.compiler(builder.top_stage, builder.config.host_target),
             target,
         });
 
@@ -700,7 +700,7 @@ fn doc_std(
     extra_args: &[&str],
     requested_crates: &[String],
 ) {
-    let compiler = builder.compiler(stage, builder.config.build);
+    let compiler = builder.compiler(stage, builder.config.host_target);
 
     let target_doc_dir_name = if format == DocumentationFormat::Json { "json-doc" } else { "doc" };
     let target_dir = builder.stage_out(compiler, Mode::Std).join(target).join(target_doc_dir_name);
@@ -803,8 +803,8 @@ impl Step for Rustc {
 
         // Build the standard library, so that proc-macros can use it.
         // (Normally, only the metadata would be necessary, but proc-macros are special since they run at compile-time.)
-        let compiler = builder.compiler(stage, builder.config.build);
-        builder.ensure(compile::Std::new(compiler, builder.config.build));
+        let compiler = builder.compiler(stage, builder.config.host_target);
+        builder.ensure(compile::Std::new(compiler, builder.config.host_target));
 
         let _guard = builder.msg_sysroot_tool(
             Kind::Doc,
@@ -946,7 +946,7 @@ macro_rules! tool_doc {
                 let out = builder.compiler_doc_out(target);
                 t!(fs::create_dir_all(&out));
 
-                let compiler = builder.compiler(stage, builder.config.build);
+                let compiler = builder.compiler(stage, builder.config.host_target);
                 builder.ensure(compile::Std::new(compiler, target));
 
                 if true $(&& $rustc_tool)? {
@@ -1174,7 +1174,7 @@ impl Step for RustcBook {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(RustcBook {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
             validate: false,
         });
@@ -1261,7 +1261,7 @@ impl Step for Reference {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Reference {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -1272,7 +1272,7 @@ impl Step for Reference {
 
         // This is needed for generating links to the standard library using
         // the mdbook-spec plugin.
-        builder.ensure(compile::Std::new(self.compiler, builder.config.build));
+        builder.ensure(compile::Std::new(self.compiler, builder.config.host_target));
 
         // Run rustbook/mdbook to generate the HTML pages.
         builder.ensure(RustbookSrc {
diff --git a/src/bootstrap/src/core/build_steps/gcc.rs b/src/bootstrap/src/core/build_steps/gcc.rs
index ee8bd8286daec..899e3fd9a45a8 100644
--- a/src/bootstrap/src/core/build_steps/gcc.rs
+++ b/src/bootstrap/src/core/build_steps/gcc.rs
@@ -285,7 +285,7 @@ pub fn add_cg_gcc_cargo_flags(cargo: &mut Cargo, gcc: &GccOutput) {
 /// The absolute path to the downloaded GCC artifacts.
 #[cfg(not(test))]
 fn ci_gcc_root(config: &crate::Config) -> PathBuf {
-    config.out.join(config.build).join("ci-gcc")
+    config.out.join(config.host_target).join("ci-gcc")
 }
 
 /// Detect whether GCC sources have been modified locally or not.
diff --git a/src/bootstrap/src/core/build_steps/install.rs b/src/bootstrap/src/core/build_steps/install.rs
index 5419540aa2e08..4434d6658eb24 100644
--- a/src/bootstrap/src/core/build_steps/install.rs
+++ b/src/bootstrap/src/core/build_steps/install.rs
@@ -73,7 +73,7 @@ fn install_sh(
     let prefix = default_path(&builder.config.prefix, "/usr/local");
     let sysconfdir = prefix.join(default_path(&builder.config.sysconfdir, "/etc"));
     let destdir_env = env::var_os("DESTDIR").map(PathBuf::from);
-    let is_cygwin = builder.config.build.is_cygwin();
+    let is_cygwin = builder.config.host_target.is_cygwin();
 
     // Sanity checks on the write access of user.
     //
@@ -187,7 +187,7 @@ macro_rules! install {
 
             fn make_run(run: RunConfig<'_>) {
                 run.builder.ensure($name {
-                    compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+                    compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
                     target: run.target,
                 });
             }
@@ -246,7 +246,7 @@ install!((self, builder, _config),
             );
         }
     };
-    LlvmTools, alias = "llvm-tools", _config.llvm_tools_enabled && _config.llvm_enabled(_config.build), only_hosts: true, {
+    LlvmTools, alias = "llvm-tools", _config.llvm_tools_enabled && _config.llvm_enabled(_config.host_target), only_hosts: true, {
         if let Some(tarball) = builder.ensure(dist::LlvmTools { target: self.target }) {
             install_sh(builder, "llvm-tools", self.compiler.stage, Some(self.target), &tarball);
         } else {
diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
index 2b7703000cbff..8f2f143c352f0 100644
--- a/src/bootstrap/src/core/build_steps/llvm.rs
+++ b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -132,14 +132,14 @@ pub fn prebuilt_llvm_config(
     let build_llvm_config = if let Some(build_llvm_config) = builder
         .config
         .target_config
-        .get(&builder.config.build)
+        .get(&builder.config.host_target)
         .and_then(|config| config.llvm_config.clone())
     {
         build_llvm_config
     } else {
-        let mut llvm_config_ret_dir = builder.llvm_out(builder.config.build);
+        let mut llvm_config_ret_dir = builder.llvm_out(builder.config.host_target);
         llvm_config_ret_dir.push("bin");
-        llvm_config_ret_dir.join(exe("llvm-config", builder.config.build))
+        llvm_config_ret_dir.join(exe("llvm-config", builder.config.host_target))
     };
 
     let llvm_cmake_dir = out_dir.join("lib/cmake/llvm");
@@ -235,8 +235,8 @@ pub(crate) fn is_ci_llvm_available_for_target(config: &Config, asserts: bool) ->
         ("x86_64-unknown-netbsd", false),
     ];
 
-    if !supported_platforms.contains(&(&*config.build.triple, asserts))
-        && (asserts || !supported_platforms.contains(&(&*config.build.triple, true)))
+    if !supported_platforms.contains(&(&*config.host_target.triple, asserts))
+        && (asserts || !supported_platforms.contains(&(&*config.host_target.triple, true)))
     {
         return false;
     }
@@ -480,7 +480,7 @@ impl Step for Llvm {
         // https://llvm.org/docs/HowToCrossCompileLLVM.html
         if !builder.config.is_host_target(target) {
             let LlvmResult { llvm_config, .. } =
-                builder.ensure(Llvm { target: builder.config.build });
+                builder.ensure(Llvm { target: builder.config.host_target });
             if !builder.config.dry_run() {
                 let llvm_bindir =
                     command(&llvm_config).arg("--bindir").run_capture_stdout(builder).stdout();
@@ -494,7 +494,8 @@ impl Step for Llvm {
             }
             cfg.define("LLVM_CONFIG_PATH", llvm_config);
             if builder.config.llvm_clang {
-                let build_bin = builder.llvm_out(builder.config.build).join("build").join("bin");
+                let build_bin =
+                    builder.llvm_out(builder.config.host_target).join("build").join("bin");
                 let clang_tblgen = build_bin.join("clang-tblgen").with_extension(EXE_EXTENSION);
                 if !builder.config.dry_run() && !clang_tblgen.exists() {
                     panic!("unable to find {}", clang_tblgen.display());
@@ -628,7 +629,7 @@ fn configure_cmake(
     if builder.ninja() {
         cfg.generator("Ninja");
     }
-    cfg.target(&target.triple).host(&builder.config.build.triple);
+    cfg.target(&target.triple).host(&builder.config.host_target.triple);
 
     if !builder.config.is_host_target(target) {
         cfg.define("CMAKE_CROSSCOMPILING", "True");
@@ -813,7 +814,7 @@ fn configure_cmake(
         ldflags.push_all(flags);
     }
 
-    if let Some(flags) = get_var("LDFLAGS", &builder.config.build.triple, &target.triple) {
+    if let Some(flags) = get_var("LDFLAGS", &builder.config.host_target.triple, &target.triple) {
         ldflags.push_all(&flags);
     }
 
@@ -1135,7 +1136,8 @@ impl Step for Sanitizers {
             return runtimes;
         }
 
-        let LlvmResult { llvm_config, .. } = builder.ensure(Llvm { target: builder.config.build });
+        let LlvmResult { llvm_config, .. } =
+            builder.ensure(Llvm { target: builder.config.host_target });
 
         static STAMP_HASH_MEMO: OnceLock<String> = OnceLock::new();
         let smart_stamp_hash = STAMP_HASH_MEMO.get_or_init(|| {
@@ -1345,7 +1347,7 @@ impl Step for CrtBeginEnd {
         cfg.cargo_metadata(false)
             .out_dir(&out_dir)
             .target(&self.target.triple)
-            .host(&builder.config.build.triple)
+            .host(&builder.config.host_target.triple)
             .warnings(false)
             .debug(false)
             .opt_level(3)
@@ -1424,7 +1426,7 @@ impl Step for Libunwind {
                 cfg.archiver(ar);
             }
             cfg.target(&self.target.triple);
-            cfg.host(&builder.config.build.triple);
+            cfg.host(&builder.config.host_target.triple);
             cfg.warnings(false);
             cfg.debug(false);
             // get_compiler() need set opt_level first.
diff --git a/src/bootstrap/src/core/build_steps/perf.rs b/src/bootstrap/src/core/build_steps/perf.rs
index 14c7b7cf5e983..c43043b48f4d8 100644
--- a/src/bootstrap/src/core/build_steps/perf.rs
+++ b/src/bootstrap/src/core/build_steps/perf.rs
@@ -136,8 +136,8 @@ impl Display for Scenario {
 /// Performs profiling using `rustc-perf` on a built version of the compiler.
 pub fn perf(builder: &Builder<'_>, args: &PerfArgs) {
     let collector = builder.ensure(RustcPerf {
-        compiler: builder.compiler(0, builder.config.build),
-        target: builder.config.build,
+        compiler: builder.compiler(0, builder.config.host_target),
+        target: builder.config.host_target,
     });
 
     let is_profiling = match &args.cmd {
@@ -151,8 +151,8 @@ pub fn perf(builder: &Builder<'_>, args: &PerfArgs) {
 Consider setting `rust.debuginfo-level = 1` in `bootstrap.toml`."#);
     }
 
-    let compiler = builder.compiler(builder.top_stage, builder.config.build);
-    builder.ensure(Std::new(compiler, builder.config.build));
+    let compiler = builder.compiler(builder.top_stage, builder.config.host_target);
+    builder.ensure(Std::new(compiler, builder.config.host_target));
 
     if let Some(opts) = args.cmd.shared_opts()
         && opts.profiles.contains(&Profile::Doc)
diff --git a/src/bootstrap/src/core/build_steps/run.rs b/src/bootstrap/src/core/build_steps/run.rs
index 6ef1b13abcde0..b3104ae05e884 100644
--- a/src/bootstrap/src/core/build_steps/run.rs
+++ b/src/bootstrap/src/core/build_steps/run.rs
@@ -116,7 +116,7 @@ impl Step for Miri {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let host = builder.build.build;
+        let host = builder.build.host_target;
         let target = self.target;
 
         // `x run` uses stage 0 by default but miri does not work well with stage 0.
@@ -448,7 +448,7 @@ impl Step for Rustfmt {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let host = builder.build.build;
+        let host = builder.build.host_target;
 
         // `x run` uses stage 0 by default but rustfmt does not work well with stage 0.
         // Change the stage to 1 if it's not set explicitly.
diff --git a/src/bootstrap/src/core/build_steps/setup.rs b/src/bootstrap/src/core/build_steps/setup.rs
index 25adfdf160157..86b7456d7b4e9 100644
--- a/src/bootstrap/src/core/build_steps/setup.rs
+++ b/src/bootstrap/src/core/build_steps/setup.rs
@@ -260,7 +260,7 @@ impl Step for Link {
         }
 
         let stage_path =
-            ["build", config.build.rustc_target_arg(), "stage1"].join(MAIN_SEPARATOR_STR);
+            ["build", config.host_target.rustc_target_arg(), "stage1"].join(MAIN_SEPARATOR_STR);
 
         if stage_dir_exists(&stage_path[..]) && !config.dry_run() {
             attempt_toolchain_link(builder, &stage_path[..]);
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index dddce8fe05d1d..ebb926d81cef4 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -70,7 +70,7 @@ impl Step for CrateBootstrap {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let bootstrap_host = builder.config.build;
+        let bootstrap_host = builder.config.host_target;
         let compiler = builder.compiler(0, bootstrap_host);
         let mut path = self.path.to_str().unwrap();
 
@@ -128,7 +128,7 @@ You can skip linkcheck with --skip src/tools/linkchecker"
         builder.info(&format!("Linkcheck ({host})"));
 
         // Test the linkchecker itself.
-        let bootstrap_host = builder.config.build;
+        let bootstrap_host = builder.config.host_target;
         let compiler = builder.compiler(0, bootstrap_host);
 
         let cargo = tool::prepare_tool_cargo(
@@ -525,7 +525,7 @@ impl Step for Miri {
 
     /// Runs `cargo test` for miri.
     fn run(self, builder: &Builder<'_>) {
-        let host = builder.build.build;
+        let host = builder.build.host_target;
         let target = self.target;
         let stage = builder.top_stage;
         if stage == 0 {
@@ -637,7 +637,7 @@ impl Step for CargoMiri {
 
     /// Tests `cargo miri test`.
     fn run(self, builder: &Builder<'_>) {
-        let host = builder.build.build;
+        let host = builder.build.host_target;
         let target = self.target;
         let stage = builder.top_stage;
         if stage == 0 {
@@ -915,7 +915,7 @@ impl Step for RustdocJSStd {
             Kind::Test,
             builder.top_stage,
             "rustdoc-js-std",
-            builder.config.build,
+            builder.config.host_target,
             self.target,
         );
         command.run(builder);
@@ -1607,7 +1607,7 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
             // At stage 0 (stage - 1) we are using the stage0 compiler. Using `self.target` can lead
             // finding an incorrect compiler path on cross-targets, as the stage 0 is always equal to
             // `build.build` in the configuration.
-            let build = builder.build.build;
+            let build = builder.build.host_target;
             compiler = builder.compiler(compiler.stage - 1, build);
             let test_stage = compiler.stage + 1;
             (test_stage, format!("stage{test_stage}-{build}"))
@@ -1729,7 +1729,7 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         cmd.arg("--mode").arg(mode);
         cmd.arg("--target").arg(target.rustc_target_arg());
         cmd.arg("--host").arg(&*compiler.host.triple);
-        cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.build));
+        cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.host_target));
 
         if builder.build.config.llvm_enzyme {
             cmd.arg("--has-enzyme");
@@ -1900,7 +1900,7 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         let mut copts_passed = false;
         if builder.config.llvm_enabled(compiler.host) {
             let llvm::LlvmResult { llvm_config, .. } =
-                builder.ensure(llvm::Llvm { target: builder.config.build });
+                builder.ensure(llvm::Llvm { target: builder.config.host_target });
             if !builder.config.dry_run() {
                 let llvm_version = get_llvm_version(builder, &llvm_config);
                 let llvm_components =
@@ -1947,7 +1947,7 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
                 // If LLD is available, add it to the PATH
                 if builder.config.lld_enabled {
                     let lld_install_root =
-                        builder.ensure(llvm::Lld { target: builder.config.build });
+                        builder.ensure(llvm::Lld { target: builder.config.host_target });
 
                     let lld_bin_path = lld_install_root.join("bin");
 
@@ -2202,7 +2202,7 @@ impl BookTest {
             let mut lib_paths = vec![];
             for dep in self.dependencies {
                 let mode = Mode::ToolRustc;
-                let target = builder.config.build;
+                let target = builder.config.host_target;
                 let cargo = tool::prepare_tool_cargo(
                     builder,
                     compiler,
@@ -2384,7 +2384,7 @@ impl Step for ErrorIndex {
         // error_index_generator depends on librustdoc. Use the compiler that
         // is normally used to build rustdoc for other tests (like compiletest
         // tests in tests/rustdoc) so that it shares the same artifacts.
-        let compiler = run.builder.compiler(run.builder.top_stage, run.builder.config.build);
+        let compiler = run.builder.compiler(run.builder.top_stage, run.builder.config.host_target);
         run.builder.ensure(ErrorIndex { compiler });
     }
 
@@ -2983,7 +2983,7 @@ impl Step for Distcheck {
             .arg("--enable-vendor")
             .current_dir(&dir)
             .run(builder);
-        command(helpers::make(&builder.config.build.triple))
+        command(helpers::make(&builder.config.host_target.triple))
             .arg("check")
             .current_dir(&dir)
             .run(builder);
@@ -3024,7 +3024,7 @@ impl Step for Bootstrap {
 
     /// Tests the build system itself.
     fn run(self, builder: &Builder<'_>) {
-        let host = builder.config.build;
+        let host = builder.config.host_target;
         let compiler = builder.compiler(0, host);
         let _guard = builder.msg(Kind::Test, 0, "bootstrap", host, host);
 
@@ -3035,7 +3035,7 @@ impl Step for Bootstrap {
         check_bootstrap
             .args(["-m", "unittest", "bootstrap_test.py"])
             .env("BUILD_DIR", &builder.out)
-            .env("BUILD_PLATFORM", builder.build.build.triple)
+            .env("BUILD_PLATFORM", builder.build.host_target.triple)
             .env("BOOTSTRAP_TEST_RUSTC_BIN", &builder.initial_rustc)
             .env("BOOTSTRAP_TEST_CARGO_BIN", &builder.initial_cargo)
             .current_dir(builder.src.join("src/bootstrap/"));
@@ -3090,8 +3090,11 @@ impl Step for TierCheck {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        let compiler =
-            run.builder.compiler_for(run.builder.top_stage, run.builder.build.build, run.target);
+        let compiler = run.builder.compiler_for(
+            run.builder.top_stage,
+            run.builder.build.host_target,
+            run.target,
+        );
         run.builder.ensure(TierCheck { compiler });
     }
 
@@ -3142,7 +3145,7 @@ impl Step for LintDocs {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(LintDocs {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -3168,7 +3171,7 @@ impl Step for RustInstaller {
 
     /// Ensure the version placeholder replacement tool builds
     fn run(self, builder: &Builder<'_>) {
-        let bootstrap_host = builder.config.build;
+        let bootstrap_host = builder.config.host_target;
         let compiler = builder.compiler(0, bootstrap_host);
         let cargo = tool::prepare_tool_cargo(
             builder,
@@ -3270,7 +3273,7 @@ impl Step for TestHelpers {
         cfg.cargo_metadata(false)
             .out_dir(&dst)
             .target(&target.triple)
-            .host(&builder.config.build.triple)
+            .host(&builder.config.host_target.triple)
             .opt_level(0)
             .warnings(false)
             .debug(false)
@@ -3560,7 +3563,7 @@ impl Step for TestFloatParse {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let bootstrap_host = builder.config.build;
+        let bootstrap_host = builder.config.host_target;
         let compiler = builder.compiler(builder.top_stage, bootstrap_host);
         let path = self.path.to_str().unwrap();
         let crate_name = self.path.iter().next_back().unwrap().to_str().unwrap();
diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
index 9861637d8c822..00df289720728 100644
--- a/src/bootstrap/src/core/build_steps/tool.rs
+++ b/src/bootstrap/src/core/build_steps/tool.rs
@@ -342,14 +342,14 @@ pub(crate) fn get_tool_rustc_compiler(
 
     if builder.download_rustc() && target_compiler.stage == 1 {
         // We shouldn't drop to stage0 compiler when using CI rustc.
-        return builder.compiler(1, builder.config.build);
+        return builder.compiler(1, builder.config.host_target);
     }
 
     // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
     // we'd have stageN/bin/rustc and stageN/bin/$rustc_tool be effectively different stage
     // compilers, which isn't what we want. Rustc tools should be linked in the same way as the
     // compiler it's paired with, so it must be built with the previous stage compiler.
-    builder.compiler(target_compiler.stage.saturating_sub(1), builder.config.build)
+    builder.compiler(target_compiler.stage.saturating_sub(1), builder.config.host_target)
 }
 
 /// Links a built tool binary with the given `name` from the build directory to the
@@ -390,8 +390,8 @@ macro_rules! bootstrap_tool {
                 match tool {
                     $(Tool::$name =>
                         self.ensure($name {
-                            compiler: self.compiler(0, self.config.build),
-                            target: self.config.build,
+                            compiler: self.compiler(0, self.config.host_target),
+                            target: self.config.host_target,
                         }).tool_path,
                     )+
                 }
@@ -415,7 +415,7 @@ macro_rules! bootstrap_tool {
             fn make_run(run: RunConfig<'_>) {
                 run.builder.ensure($name {
                     // snapshot compiler
-                    compiler: run.builder.compiler(0, run.builder.config.build),
+                    compiler: run.builder.compiler(0, run.builder.config.host_target),
                     target: run.target,
                 });
             }
@@ -532,7 +532,7 @@ impl Step for RustcPerf {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(RustcPerf {
-            compiler: run.builder.compiler(0, run.builder.config.build),
+            compiler: run.builder.compiler(0, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -573,7 +573,7 @@ impl ErrorIndex {
     pub fn command(builder: &Builder<'_>) -> BootstrapCommand {
         // Error-index-generator links with the rustdoc library, so we need to add `rustc_lib_paths`
         // for rustc_private and libLLVM.so, and `sysroot_lib` for libstd, etc.
-        let host = builder.config.build;
+        let host = builder.config.host_target;
         let compiler = builder.compiler_for(builder.top_stage, host, host);
         let mut cmd = command(builder.ensure(ErrorIndex { compiler }).tool_path);
         let mut dylib_paths = builder.rustc_lib_paths(compiler);
@@ -596,7 +596,7 @@ impl Step for ErrorIndex {
         // src/tools/error-index-generator` which almost nobody does.
         // Normally, `x.py test` or `x.py doc` will use the
         // `ErrorIndex::command` function instead.
-        let compiler = run.builder.compiler(run.builder.top_stage, run.builder.config.build);
+        let compiler = run.builder.compiler(run.builder.top_stage, run.builder.config.host_target);
         run.builder.ensure(ErrorIndex { compiler });
     }
 
@@ -631,7 +631,7 @@ impl Step for RemoteTestServer {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(RemoteTestServer {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -788,7 +788,7 @@ impl Step for Cargo {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(Cargo {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -906,7 +906,7 @@ impl Step for RustAnalyzer {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(RustAnalyzer {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -951,7 +951,7 @@ impl Step for RustAnalyzerProcMacroSrv {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(RustAnalyzerProcMacroSrv {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             target: run.target,
         });
     }
@@ -1004,7 +1004,7 @@ impl Step for LlvmBitcodeLinker {
 
     fn make_run(run: RunConfig<'_>) {
         run.builder.ensure(LlvmBitcodeLinker {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
             extra_features: Vec::new(),
             target: run.target,
         });
@@ -1142,7 +1142,7 @@ macro_rules! tool_extended {
 
             fn make_run(run: RunConfig<'_>) {
                 run.builder.ensure($name {
-                    compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+                    compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.host_target),
                     target: run.target,
                 });
             }
@@ -1284,7 +1284,7 @@ impl Step for TestFloatParse {
     }
 
     fn run(self, builder: &Builder<'_>) -> ToolBuildResult {
-        let bootstrap_host = builder.config.build;
+        let bootstrap_host = builder.config.host_target;
         let compiler = builder.compiler(builder.top_stage, bootstrap_host);
 
         builder.ensure(ToolBuild {
@@ -1307,7 +1307,7 @@ impl Builder<'_> {
     /// `host`.
     pub fn tool_cmd(&self, tool: Tool) -> BootstrapCommand {
         let mut cmd = command(self.tool_exe(tool));
-        let compiler = self.compiler(0, self.config.build);
+        let compiler = self.compiler(0, self.config.host_target);
         let host = &compiler.host;
         // Prepares the `cmd` provided to be able to run the `compiler` provided.
         //
diff --git a/src/bootstrap/src/core/builder/mod.rs b/src/bootstrap/src/core/builder/mod.rs
index 19b79bfe818c2..9564a5985bba4 100644
--- a/src/bootstrap/src/core/builder/mod.rs
+++ b/src/bootstrap/src/core/builder/mod.rs
@@ -136,7 +136,7 @@ pub struct RunConfig<'a> {
 
 impl RunConfig<'_> {
     pub fn build_triple(&self) -> TargetSelection {
-        self.builder.build.build
+        self.builder.build.host_target
     }
 
     /// Return a list of crate names selected by `run.paths`.
@@ -1294,10 +1294,10 @@ impl<'a> Builder<'a> {
     ) -> Compiler {
         let mut resolved_compiler = if self.build.force_use_stage2(stage) {
             trace!(target: "COMPILER_FOR", ?stage, "force_use_stage2");
-            self.compiler(2, self.config.build)
+            self.compiler(2, self.config.host_target)
         } else if self.build.force_use_stage1(stage, target) {
             trace!(target: "COMPILER_FOR", ?stage, "force_use_stage1");
-            self.compiler(1, self.config.build)
+            self.compiler(1, self.config.host_target)
         } else {
             trace!(target: "COMPILER_FOR", ?stage, ?host, "no force, fallback to `compiler()`");
             self.compiler(stage, host)
@@ -1355,7 +1355,7 @@ impl<'a> Builder<'a> {
     /// Windows.
     pub fn libdir_relative(&self, compiler: Compiler) -> &Path {
         if compiler.is_snapshot(self) {
-            libdir(self.config.build).as_ref()
+            libdir(self.config.host_target).as_ref()
         } else {
             match self.config.libdir_relative() {
                 Some(relative_libdir) if compiler.stage >= 1 => relative_libdir,
@@ -1436,9 +1436,10 @@ impl<'a> Builder<'a> {
             return cmd;
         }
 
-        let _ = self.ensure(tool::Clippy { compiler: run_compiler, target: self.build.build });
-        let cargo_clippy =
-            self.ensure(tool::CargoClippy { compiler: run_compiler, target: self.build.build });
+        let _ =
+            self.ensure(tool::Clippy { compiler: run_compiler, target: self.build.host_target });
+        let cargo_clippy = self
+            .ensure(tool::CargoClippy { compiler: run_compiler, target: self.build.host_target });
         let mut dylib_path = helpers::dylib_path();
         dylib_path.insert(0, self.sysroot(run_compiler).join("lib"));
 
@@ -1451,9 +1452,10 @@ impl<'a> Builder<'a> {
     pub fn cargo_miri_cmd(&self, run_compiler: Compiler) -> BootstrapCommand {
         assert!(run_compiler.stage > 0, "miri can not be invoked at stage 0");
         // Prepare the tools
-        let miri = self.ensure(tool::Miri { compiler: run_compiler, target: self.build.build });
+        let miri =
+            self.ensure(tool::Miri { compiler: run_compiler, target: self.build.host_target });
         let cargo_miri =
-            self.ensure(tool::CargoMiri { compiler: run_compiler, target: self.build.build });
+            self.ensure(tool::CargoMiri { compiler: run_compiler, target: self.build.host_target });
         // Invoke cargo-miri, make sure it can find miri and cargo.
         let mut cmd = command(cargo_miri.tool_path);
         cmd.env("MIRI", &miri.tool_path);
diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index baa22fc7f72af..12faf304fcc82 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -46,7 +46,7 @@ fn configure_with_args(cmd: &[String], host: &[&str], target: &[&str]) -> Config
         .join(&thread::current().name().unwrap_or("unknown").replace(":", "-"));
     t!(fs::create_dir_all(&dir));
     config.out = dir;
-    config.build = TargetSelection::from_user(TEST_TRIPLE_1);
+    config.host_target = TargetSelection::from_user(TEST_TRIPLE_1);
     config.hosts = host.iter().map(|s| TargetSelection::from_user(s)).collect();
     config.targets = target.iter().map(|s| TargetSelection::from_user(s)).collect();
     config
@@ -1102,7 +1102,7 @@ fn test_prebuilt_llvm_config_path_resolution() {
     let actual = drop_win_disk_prefix_if_present(actual);
     assert_eq!(expected, actual);
 
-    let actual = prebuilt_llvm_config(&builder, builder.config.build, false)
+    let actual = prebuilt_llvm_config(&builder, builder.config.host_target, false)
         .llvm_result()
         .llvm_config
         .clone();
@@ -1120,15 +1120,15 @@ fn test_prebuilt_llvm_config_path_resolution() {
     let build = Build::new(config.clone());
     let builder = Builder::new(&build);
 
-    let actual = prebuilt_llvm_config(&builder, builder.config.build, false)
+    let actual = prebuilt_llvm_config(&builder, builder.config.host_target, false)
         .llvm_result()
         .llvm_config
         .clone();
     let expected = builder
         .out
-        .join(builder.config.build)
+        .join(builder.config.host_target)
         .join("llvm/bin")
-        .join(exe("llvm-config", builder.config.build));
+        .join(exe("llvm-config", builder.config.host_target));
     assert_eq!(expected, actual);
 
     let config = configure(
@@ -1143,15 +1143,15 @@ fn test_prebuilt_llvm_config_path_resolution() {
         let build = Build::new(config.clone());
         let builder = Builder::new(&build);
 
-        let actual = prebuilt_llvm_config(&builder, builder.config.build, false)
+        let actual = prebuilt_llvm_config(&builder, builder.config.host_target, false)
             .llvm_result()
             .llvm_config
             .clone();
         let expected = builder
             .out
-            .join(builder.config.build)
+            .join(builder.config.host_target)
             .join("ci-llvm/bin")
-            .join(exe("llvm-config", builder.config.build));
+            .join(exe("llvm-config", builder.config.host_target));
         assert_eq!(expected, actual);
     }
 }
@@ -1163,7 +1163,7 @@ fn test_is_builder_target() {
 
     for (target1, target2) in [(target1, target2), (target2, target1)] {
         let mut config = configure("build", &[], &[]);
-        config.build = target1;
+        config.host_target = target1;
         let build = Build::new(config);
         let builder = Builder::new(&build);
 
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 824b159c3263e..f0403427a9b5b 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -233,7 +233,7 @@ pub struct Config {
 
     pub reproducible_artifacts: Vec<String>,
 
-    pub build: TargetSelection,
+    pub host_target: TargetSelection,
     pub hosts: Vec<TargetSelection>,
     pub targets: Vec<TargetSelection>,
     pub local_rebuild: bool,
@@ -356,7 +356,7 @@ impl Config {
             stderr_is_tty: std::io::stderr().is_terminal(),
 
             // set by build.rs
-            build: TargetSelection::from_user(env!("BUILD_TRIPLE")),
+            host_target: TargetSelection::from_user(env!("BUILD_TRIPLE")),
 
             src: {
                 let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
@@ -729,7 +729,7 @@ impl Config {
         config.jobs = Some(threads_from_config(flags.jobs.unwrap_or(jobs.unwrap_or(0))));
 
         if let Some(file_build) = build {
-            config.build = TargetSelection::from_user(&file_build);
+            config.host_target = TargetSelection::from_user(&file_build);
         };
 
         set(&mut config.out, flags.build_dir.or_else(|| build_dir.map(PathBuf::from)));
@@ -755,10 +755,10 @@ impl Config {
             config.download_beta_toolchain();
             config
                 .out
-                .join(config.build)
+                .join(config.host_target)
                 .join("stage0")
                 .join("bin")
-                .join(exe("rustc", config.build))
+                .join(exe("rustc", config.host_target))
         };
 
         config.initial_sysroot = t!(PathBuf::from_str(
@@ -774,7 +774,7 @@ impl Config {
             cargo
         } else {
             config.download_beta_toolchain();
-            config.initial_sysroot.join("bin").join(exe("cargo", config.build))
+            config.initial_sysroot.join("bin").join(exe("cargo", config.host_target))
         };
 
         // NOTE: it's important this comes *after* we set `initial_rustc` just above.
@@ -789,7 +789,7 @@ impl Config {
         } else if let Some(file_host) = host {
             file_host.iter().map(|h| TargetSelection::from_user(h)).collect()
         } else {
-            vec![config.build]
+            vec![config.host_target]
         };
         config.targets = if let Some(TargetSelectionList(arg_target)) = flags.target {
             arg_target
@@ -921,17 +921,19 @@ impl Config {
         }
 
         if config.llvm_from_ci {
-            let triple = &config.build.triple;
+            let triple = &config.host_target.triple;
             let ci_llvm_bin = config.ci_llvm_root().join("bin");
             let build_target = config
                 .target_config
-                .entry(config.build)
+                .entry(config.host_target)
                 .or_insert_with(|| Target::from_triple(triple));
 
             check_ci_llvm!(build_target.llvm_config);
             check_ci_llvm!(build_target.llvm_filecheck);
-            build_target.llvm_config = Some(ci_llvm_bin.join(exe("llvm-config", config.build)));
-            build_target.llvm_filecheck = Some(ci_llvm_bin.join(exe("FileCheck", config.build)));
+            build_target.llvm_config =
+                Some(ci_llvm_bin.join(exe("llvm-config", config.host_target)));
+            build_target.llvm_filecheck =
+                Some(ci_llvm_bin.join(exe("FileCheck", config.host_target)));
         }
 
         config.apply_dist_config(toml.dist);
@@ -948,7 +950,7 @@ impl Config {
             );
         }
 
-        if config.lld_enabled && config.is_system_llvm(config.build) {
+        if config.lld_enabled && config.is_system_llvm(config.host_target) {
             eprintln!(
                 "Warning: LLD is enabled when using external llvm-config. LLD will not be built and copied to the sysroot."
             );
@@ -1157,13 +1159,13 @@ impl Config {
     /// The absolute path to the downloaded LLVM artifacts.
     pub(crate) fn ci_llvm_root(&self) -> PathBuf {
         assert!(self.llvm_from_ci);
-        self.out.join(self.build).join("ci-llvm")
+        self.out.join(self.host_target).join("ci-llvm")
     }
 
     /// Directory where the extracted `rustc-dev` component is stored.
     pub(crate) fn ci_rustc_dir(&self) -> PathBuf {
         assert!(self.download_rustc());
-        self.out.join(self.build).join("ci-rustc")
+        self.out.join(self.host_target).join("ci-rustc")
     }
 
     /// Determine whether llvm should be linked dynamically.
@@ -1247,7 +1249,7 @@ impl Config {
                         // Check the config compatibility
                         // FIXME: this doesn't cover `--set` flags yet.
                         let res = check_incompatible_options_for_ci_rustc(
-                            self.build,
+                            self.host_target,
                             current_config_toml,
                             ci_config_toml,
                         );
@@ -1485,7 +1487,7 @@ impl Config {
         debug_assertions_requested: bool,
         llvm_assertions: bool,
     ) -> Option<String> {
-        if !is_download_ci_available(&self.build.triple, llvm_assertions) {
+        if !is_download_ci_available(&self.host_target.triple, llvm_assertions) {
             return None;
         }
 
@@ -1721,7 +1723,7 @@ impl Config {
 
     /// Checks if the given target is the same as the host target.
     pub fn is_host_target(&self, target: TargetSelection) -> bool {
-        self.build == target
+        self.host_target == target
     }
 
     /// Returns `true` if this is an external version of LLVM not managed by bootstrap.
diff --git a/src/bootstrap/src/core/config/flags.rs b/src/bootstrap/src/core/config/flags.rs
index 30617f58d4306..7947cbf1ae20f 100644
--- a/src/bootstrap/src/core/config/flags.rs
+++ b/src/bootstrap/src/core/config/flags.rs
@@ -59,7 +59,7 @@ pub struct Flags {
     pub build_dir: Option<PathBuf>,
 
     #[arg(global = true, long, value_hint = clap::ValueHint::Other, value_name = "BUILD")]
-    /// build target of the stage0 compiler
+    /// host target of the stage0 compiler
     pub build: Option<String>,
 
     #[arg(global = true, long, value_hint = clap::ValueHint::Other, value_name = "HOST", value_parser = target_selection_list)]
diff --git a/src/bootstrap/src/core/config/toml/mod.rs b/src/bootstrap/src/core/config/toml/mod.rs
index ac4e249e5802d..01eb243159cea 100644
--- a/src/bootstrap/src/core/config/toml/mod.rs
+++ b/src/bootstrap/src/core/config/toml/mod.rs
@@ -147,7 +147,7 @@ impl Config {
         }
 
         let builder_config_path =
-            self.out.join(self.build.triple).join(build_name).join(BUILDER_CONFIG_FILENAME);
+            self.out.join(self.host_target.triple).join(build_name).join(BUILDER_CONFIG_FILENAME);
         Self::get_toml(&builder_config_path)
     }
 
diff --git a/src/bootstrap/src/core/config/toml/rust.rs b/src/bootstrap/src/core/config/toml/rust.rs
index 81f95f356a56b..d1c5c0c8eb3a7 100644
--- a/src/bootstrap/src/core/config/toml/rust.rs
+++ b/src/bootstrap/src/core/config/toml/rust.rs
@@ -622,13 +622,13 @@ impl Config {
         //   thus, disabled
         // - similarly, lld will not be built nor used by default when explicitly asked not to, e.g.
         //   when the config sets `rust.lld = false`
-        if self.build.triple == "x86_64-unknown-linux-gnu"
-            && self.hosts == [self.build]
+        if self.host_target.triple == "x86_64-unknown-linux-gnu"
+            && self.hosts == [self.host_target]
             && (self.channel == "dev" || self.channel == "nightly")
         {
             let no_llvm_config = self
                 .target_config
-                .get(&self.build)
+                .get(&self.host_target)
                 .is_some_and(|target_config| target_config.llvm_config.is_none());
             let enable_lld = self.llvm_from_ci || no_llvm_config;
             // Prefer the config setting in case an explicit opt-out is needed.
diff --git a/src/bootstrap/src/core/config/toml/target.rs b/src/bootstrap/src/core/config/toml/target.rs
index 7f074d1b25e08..81add8f2d16e3 100644
--- a/src/bootstrap/src/core/config/toml/target.rs
+++ b/src/bootstrap/src/core/config/toml/target.rs
@@ -101,7 +101,7 @@ impl Config {
                 let mut target = Target::from_triple(&triple);
 
                 if let Some(ref s) = cfg.llvm_config {
-                    if self.download_rustc_commit.is_some() && triple == *self.build.triple {
+                    if self.download_rustc_commit.is_some() && triple == *self.host_target.triple {
                         panic!(
                             "setting llvm_config for the host is incompatible with download-rustc"
                         );
diff --git a/src/bootstrap/src/core/download.rs b/src/bootstrap/src/core/download.rs
index ba00b405c61d3..868f505b43e1f 100644
--- a/src/bootstrap/src/core/download.rs
+++ b/src/bootstrap/src/core/download.rs
@@ -272,7 +272,7 @@ impl Config {
         }
         curl.arg(url);
         if !self.check_run(&mut curl) {
-            if self.build.contains("windows-msvc") {
+            if self.host_target.contains("windows-msvc") {
                 eprintln!("Fallback to PowerShell");
                 for _ in 0..3 {
                     if try_run(self, Command::new("PowerShell.exe").args([
@@ -424,7 +424,7 @@ impl Config {
 
         let date = &self.stage0_metadata.compiler.date;
         let version = &self.stage0_metadata.compiler.version;
-        let host = self.build;
+        let host = self.host_target;
 
         let clippy_stamp =
             BuildStamp::new(&self.initial_sysroot).with_prefix("clippy").add_stamp(date);
@@ -462,7 +462,7 @@ impl Config {
         let VersionMetadata { date, version } = self.stage0_metadata.rustfmt.as_ref()?;
         let channel = format!("{version}-{date}");
 
-        let host = self.build;
+        let host = self.host_target;
         let bin_root = self.out.join(host).join("rustfmt");
         let rustfmt_path = bin_root.join("bin").join(exe("rustfmt", host));
         let rustfmt_stamp = BuildStamp::new(&bin_root).with_prefix("rustfmt").add_stamp(channel);
@@ -570,11 +570,11 @@ impl Config {
         extra_components: &[&str],
         download_component: fn(&Config, String, &str, &str),
     ) {
-        let host = self.build.triple;
+        let host = self.host_target.triple;
         let bin_root = self.out.join(host).join(sysroot);
         let rustc_stamp = BuildStamp::new(&bin_root).with_prefix("rustc").add_stamp(stamp_key);
 
-        if !bin_root.join("bin").join(exe("rustc", self.build)).exists()
+        if !bin_root.join("bin").join(exe("rustc", self.host_target)).exists()
             || !rustc_stamp.is_up_to_date()
         {
             if bin_root.exists() {
@@ -643,7 +643,7 @@ impl Config {
             t!(fs::create_dir_all(&cache_dir));
         }
 
-        let bin_root = self.out.join(self.build).join(destination);
+        let bin_root = self.out.join(self.host_target).join(destination);
         let tarball = cache_dir.join(&filename);
         let (base_url, url, should_verify) = match mode {
             DownloadSource::CI => {
@@ -772,7 +772,7 @@ download-rustc = false
             let now = std::time::SystemTime::now();
             let file_times = fs::FileTimes::new().set_accessed(now).set_modified(now);
 
-            let llvm_config = llvm_root.join("bin").join(exe("llvm-config", self.build));
+            let llvm_config = llvm_root.join("bin").join(exe("llvm-config", self.host_target));
             t!(crate::utils::helpers::set_file_times(llvm_config, file_times));
 
             if self.should_fix_bins_and_dylibs() {
@@ -827,7 +827,7 @@ download-rustc = false
             &self.stage0_metadata.config.artifacts_server
         };
         let version = self.artifact_version_part(llvm_sha);
-        let filename = format!("rust-dev-{}-{}.tar.xz", version, self.build.triple);
+        let filename = format!("rust-dev-{}-{}.tar.xz", version, self.host_target.triple);
         let tarball = rustc_cache.join(&filename);
         if !tarball.exists() {
             let help_on_error = "ERROR: failed to download llvm from ci
@@ -857,7 +857,7 @@ download-rustc = false
         }
         let base = &self.stage0_metadata.config.artifacts_server;
         let version = self.artifact_version_part(gcc_sha);
-        let filename = format!("gcc-{version}-{}.tar.xz", self.build.triple);
+        let filename = format!("gcc-{version}-{}.tar.xz", self.host_target.triple);
         let tarball = gcc_cache.join(&filename);
         if !tarball.exists() {
             let help_on_error = "ERROR: failed to download gcc from ci
diff --git a/src/bootstrap/src/core/sanity.rs b/src/bootstrap/src/core/sanity.rs
index 59ae303e21e81..1ecc5aa6fc56e 100644
--- a/src/bootstrap/src/core/sanity.rs
+++ b/src/bootstrap/src/core/sanity.rs
@@ -109,9 +109,9 @@ pub fn check(build: &mut Build) {
 
     // Ensure that a compatible version of libstdc++ is available on the system when using `llvm.download-ci-llvm`.
     #[cfg(not(test))]
-    if !build.config.dry_run() && !build.build.is_msvc() && build.config.llvm_from_ci {
+    if !build.config.dry_run() && !build.host_target.is_msvc() && build.config.llvm_from_ci {
         let builder = Builder::new(build);
-        let libcxx_version = builder.ensure(tool::LibcxxVersionTool { target: build.build });
+        let libcxx_version = builder.ensure(tool::LibcxxVersionTool { target: build.host_target });
 
         match libcxx_version {
             tool::LibcxxVersion::Gnu(version) => {
@@ -237,7 +237,7 @@ than building it.
         }
 
         // skip check for cross-targets
-        if skip_target_sanity && target != &build.build {
+        if skip_target_sanity && target != &build.host_target {
             continue;
         }
 
@@ -308,7 +308,7 @@ than building it.
 
             if build.config.llvm_enabled(*host) {
                 // Externally configured LLVM requires FileCheck to exist
-                let filecheck = build.llvm_filecheck(build.build);
+                let filecheck = build.llvm_filecheck(build.host_target);
                 if !filecheck.starts_with(&build.out)
                     && !filecheck.exists()
                     && build.config.codegen_tests
@@ -333,7 +333,7 @@ than building it.
         }
 
         // skip check for cross-targets
-        if skip_target_sanity && target != &build.build {
+        if skip_target_sanity && target != &build.host_target {
             continue;
         }
 
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 7db57889009e9..8e26a4529f34e 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -174,7 +174,7 @@ pub struct Build {
     verbosity: usize,
 
     /// Build triple for the pre-compiled snapshot compiler.
-    build: TargetSelection,
+    host_target: TargetSelection,
     /// Which triples to produce a compiler toolchain for.
     hosts: Vec<TargetSelection>,
     /// Which triples to build libraries (core/alloc/std/test/proc_macro) for.
@@ -420,7 +420,7 @@ impl Build {
         if bootstrap_out.ends_with("deps") {
             bootstrap_out.pop();
         }
-        if !bootstrap_out.join(exe("rustc", config.build)).exists() && !cfg!(test) {
+        if !bootstrap_out.join(exe("rustc", config.host_target)).exists() && !cfg!(test) {
             // this restriction can be lifted whenever https://github.com/rust-lang/rfcs/pull/3028 is implemented
             panic!(
                 "`rustc` not found in {}, run `cargo build --bins` before `cargo run`",
@@ -436,7 +436,9 @@ impl Build {
             initial_lld,
             initial_relative_libdir,
             initial_rustc: config.initial_rustc.clone(),
-            initial_rustdoc: config.initial_rustc.with_file_name(exe("rustdoc", config.build)),
+            initial_rustdoc: config
+                .initial_rustc
+                .with_file_name(exe("rustdoc", config.host_target)),
             initial_cargo: config.initial_cargo.clone(),
             initial_sysroot: config.initial_sysroot.clone(),
             local_rebuild: config.local_rebuild,
@@ -444,7 +446,7 @@ impl Build {
             doc_tests: config.cmd.doc_tests(),
             verbosity: config.verbose,
 
-            build: config.build,
+            host_target: config.host_target,
             hosts: config.hosts.clone(),
             targets: config.targets.clone(),
 
@@ -522,7 +524,7 @@ impl Build {
         }
 
         // Create symbolic link to use host sysroot from a consistent path (e.g., in the rust-analyzer config file).
-        let build_triple = build.out.join(build.build);
+        let build_triple = build.out.join(build.host_target);
         t!(fs::create_dir_all(&build_triple));
         let host = build.out.join("host");
         if host.is_symlink() {
@@ -940,7 +942,7 @@ impl Build {
 
     /// Returns the libdir of the snapshot compiler.
     fn rustc_snapshot_libdir(&self) -> PathBuf {
-        self.rustc_snapshot_sysroot().join(libdir(self.config.build))
+        self.rustc_snapshot_sysroot().join(libdir(self.config.host_target))
     }
 
     /// Returns the sysroot of the snapshot compiler.
@@ -1108,7 +1110,7 @@ Executed at: {executed_at}"#,
         what: impl Display,
         target: impl Into<Option<TargetSelection>>,
     ) -> Option<gha::Group> {
-        self.msg(Kind::Clippy, self.config.stage, what, self.config.build, target)
+        self.msg(Kind::Clippy, self.config.stage, what, self.config.host_target, target)
     }
 
     #[must_use = "Groups should not be dropped until the Step finishes running"]
@@ -1123,7 +1125,7 @@ Executed at: {executed_at}"#,
             Kind::Check,
             custom_stage.unwrap_or(self.config.stage),
             what,
-            self.config.build,
+            self.config.host_target,
             target,
         )
     }
@@ -1381,7 +1383,7 @@ Executed at: {executed_at}"#,
             Some(self.cc(target))
         } else if self.config.lld_mode.is_used()
             && self.is_lld_direct_linker(target)
-            && self.build == target
+            && self.host_target == target
         {
             match self.config.lld_mode {
                 LldMode::SelfContained => Some(self.initial_lld.clone()),
@@ -1535,7 +1537,7 @@ Executed at: {executed_at}"#,
 
     /// Path to the python interpreter to use
     fn python(&self) -> &Path {
-        if self.config.build.ends_with("apple-darwin") {
+        if self.config.host_target.ends_with("apple-darwin") {
             // Force /usr/bin/python3 on macOS for LLDB tests because we're loading the
             // LLDB plugin's compiled module which only works with the system python
             // (namely not Homebrew-installed python)
@@ -1575,7 +1577,7 @@ Executed at: {executed_at}"#,
         !self.config.full_bootstrap
             && !self.config.download_rustc()
             && stage >= 2
-            && (self.hosts.contains(&target) || target == self.build)
+            && (self.hosts.contains(&target) || target == self.host_target)
     }
 
     /// Checks whether the `compiler` compiling for `target` should be forced to
@@ -2012,7 +2014,7 @@ to download LLVM rather than building it.
         // In these cases we automatically enable Ninja if we find it in the
         // environment.
         if !self.config.ninja_in_file
-            && self.config.build.is_msvc()
+            && self.config.host_target.is_msvc()
             && cmd_finder.maybe_have("ninja").is_some()
         {
             return true;
@@ -2071,7 +2073,7 @@ impl Compiler {
 
     /// Returns `true` if this is a snapshot compiler for `build`'s configuration
     pub fn is_snapshot(&self, build: &Build) -> bool {
-        self.stage == 0 && self.host == build.build
+        self.stage == 0 && self.host == build.host_target
     }
 
     /// Indicates whether the compiler was forced to use a specific stage.
diff --git a/src/bootstrap/src/utils/cc_detect.rs b/src/bootstrap/src/utils/cc_detect.rs
index 5c9e30706ee0d..851bb38074ef7 100644
--- a/src/bootstrap/src/utils/cc_detect.rs
+++ b/src/bootstrap/src/utils/cc_detect.rs
@@ -39,7 +39,7 @@ fn new_cc_build(build: &Build, target: TargetSelection) -> cc::Build {
         // Compress debuginfo
         .flag_if_supported("-gz")
         .target(&target.triple)
-        .host(&build.build.triple);
+        .host(&build.host_target.triple);
     match build.crt_static(target) {
         Some(a) => {
             cfg.static_crt(a);
@@ -70,7 +70,7 @@ pub fn find(build: &Build) {
         | crate::Subcommand::Suggest { .. }
         | crate::Subcommand::Format { .. }
         | crate::Subcommand::Setup { .. } => {
-            build.hosts.iter().cloned().chain(iter::once(build.build)).collect()
+            build.hosts.iter().cloned().chain(iter::once(build.host_target)).collect()
         }
 
         _ => {
@@ -81,7 +81,7 @@ pub fn find(build: &Build) {
                 .iter()
                 .chain(&build.hosts)
                 .cloned()
-                .chain(iter::once(build.build))
+                .chain(iter::once(build.host_target))
                 .collect()
         }
     };
diff --git a/src/bootstrap/src/utils/cc_detect/tests.rs b/src/bootstrap/src/utils/cc_detect/tests.rs
index 225fb7619b55a..1f50738959fbb 100644
--- a/src/bootstrap/src/utils/cc_detect/tests.rs
+++ b/src/bootstrap/src/utils/cc_detect/tests.rs
@@ -155,7 +155,7 @@ fn test_find() {
     build.targets.push(target1.clone());
     build.hosts.push(target2.clone());
     find(&build);
-    for t in build.hosts.iter().chain(build.targets.iter()).chain(iter::once(&build.build)) {
+    for t in build.hosts.iter().chain(build.targets.iter()).chain(iter::once(&build.host_target)) {
         assert!(build.cc.borrow().contains_key(t), "CC not set for target {}", t.triple);
     }
 }
diff --git a/src/etc/completions/x.fish b/src/etc/completions/x.fish
index 10a4e684e3394..a030f45830ea2 100644
--- a/src/etc/completions/x.fish
+++ b/src/etc/completions/x.fish
@@ -26,7 +26,7 @@ end
 
 complete -c x -n "__fish_x_needs_command" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_needs_command" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_needs_command" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_needs_command" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_needs_command" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_needs_command" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_needs_command" -l exclude -d 'build paths to exclude' -r -F
@@ -78,7 +78,7 @@ complete -c x -n "__fish_x_needs_command" -a "vendor" -d 'Vendor dependencies'
 complete -c x -n "__fish_x_needs_command" -a "perf" -d 'Perform profiling and benchmarking of the compiler using `rustc-perf`'
 complete -c x -n "__fish_x_using_subcommand build" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand build" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand build" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand build" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand build" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand build" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand build" -l exclude -d 'build paths to exclude' -r -F
@@ -113,7 +113,7 @@ complete -c x -n "__fish_x_using_subcommand build" -l skip-std-check-if-no-downl
 complete -c x -n "__fish_x_using_subcommand build" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand check" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand check" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand check" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand check" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand check" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand check" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand check" -l exclude -d 'build paths to exclude' -r -F
@@ -153,7 +153,7 @@ complete -c x -n "__fish_x_using_subcommand clippy" -s W -d 'clippy lints to war
 complete -c x -n "__fish_x_using_subcommand clippy" -s F -d 'clippy lints to forbid' -r
 complete -c x -n "__fish_x_using_subcommand clippy" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand clippy" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand clippy" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand clippy" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand clippy" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand clippy" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand clippy" -l exclude -d 'build paths to exclude' -r -F
@@ -191,7 +191,7 @@ complete -c x -n "__fish_x_using_subcommand clippy" -l skip-std-check-if-no-down
 complete -c x -n "__fish_x_using_subcommand clippy" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand fix" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand fix" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand fix" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand fix" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand fix" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand fix" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand fix" -l exclude -d 'build paths to exclude' -r -F
@@ -226,7 +226,7 @@ complete -c x -n "__fish_x_using_subcommand fix" -l skip-std-check-if-no-downloa
 complete -c x -n "__fish_x_using_subcommand fix" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand fmt" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand fmt" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand fmt" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand fmt" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand fmt" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand fmt" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand fmt" -l exclude -d 'build paths to exclude' -r -F
@@ -263,7 +263,7 @@ complete -c x -n "__fish_x_using_subcommand fmt" -l skip-std-check-if-no-downloa
 complete -c x -n "__fish_x_using_subcommand fmt" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand doc" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand doc" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand doc" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand doc" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand doc" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand doc" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand doc" -l exclude -d 'build paths to exclude' -r -F
@@ -306,7 +306,7 @@ complete -c x -n "__fish_x_using_subcommand test" -l pass -d 'force {check,build
 complete -c x -n "__fish_x_using_subcommand test" -l run -d 'whether to execute run-* tests' -r
 complete -c x -n "__fish_x_using_subcommand test" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand test" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand test" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand test" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand test" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand test" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand test" -l exclude -d 'build paths to exclude' -r -F
@@ -350,7 +350,7 @@ complete -c x -n "__fish_x_using_subcommand test" -s h -l help -d 'Print help (s
 complete -c x -n "__fish_x_using_subcommand miri" -l test-args -d 'extra arguments to be passed for the test tool being used (e.g. libtest, compiletest or rustdoc)' -r
 complete -c x -n "__fish_x_using_subcommand miri" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand miri" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand miri" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand miri" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand miri" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand miri" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand miri" -l exclude -d 'build paths to exclude' -r -F
@@ -389,7 +389,7 @@ complete -c x -n "__fish_x_using_subcommand miri" -s h -l help -d 'Print help (s
 complete -c x -n "__fish_x_using_subcommand bench" -l test-args -r
 complete -c x -n "__fish_x_using_subcommand bench" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand bench" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand bench" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand bench" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand bench" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand bench" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand bench" -l exclude -d 'build paths to exclude' -r -F
@@ -425,7 +425,7 @@ complete -c x -n "__fish_x_using_subcommand bench" -s h -l help -d 'Print help (
 complete -c x -n "__fish_x_using_subcommand clean" -l stage -d 'Clean a specific stage without touching other artifacts. By default, every stage is cleaned if this option is not used' -r
 complete -c x -n "__fish_x_using_subcommand clean" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand clean" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand clean" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand clean" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand clean" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand clean" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand clean" -l exclude -d 'build paths to exclude' -r -F
@@ -460,7 +460,7 @@ complete -c x -n "__fish_x_using_subcommand clean" -l skip-std-check-if-no-downl
 complete -c x -n "__fish_x_using_subcommand clean" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand dist" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand dist" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand dist" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand dist" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand dist" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand dist" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand dist" -l exclude -d 'build paths to exclude' -r -F
@@ -495,7 +495,7 @@ complete -c x -n "__fish_x_using_subcommand dist" -l skip-std-check-if-no-downlo
 complete -c x -n "__fish_x_using_subcommand dist" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand install" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand install" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand install" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand install" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand install" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand install" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand install" -l exclude -d 'build paths to exclude' -r -F
@@ -531,7 +531,7 @@ complete -c x -n "__fish_x_using_subcommand install" -s h -l help -d 'Print help
 complete -c x -n "__fish_x_using_subcommand run" -l args -d 'arguments for the tool' -r
 complete -c x -n "__fish_x_using_subcommand run" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand run" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand run" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand run" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand run" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand run" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand run" -l exclude -d 'build paths to exclude' -r -F
@@ -566,7 +566,7 @@ complete -c x -n "__fish_x_using_subcommand run" -l skip-std-check-if-no-downloa
 complete -c x -n "__fish_x_using_subcommand run" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand setup" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand setup" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand setup" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand setup" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand setup" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand setup" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand setup" -l exclude -d 'build paths to exclude' -r -F
@@ -601,7 +601,7 @@ complete -c x -n "__fish_x_using_subcommand setup" -l skip-std-check-if-no-downl
 complete -c x -n "__fish_x_using_subcommand setup" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand suggest" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand suggest" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand suggest" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand suggest" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand suggest" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand suggest" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand suggest" -l exclude -d 'build paths to exclude' -r -F
@@ -638,7 +638,7 @@ complete -c x -n "__fish_x_using_subcommand suggest" -s h -l help -d 'Print help
 complete -c x -n "__fish_x_using_subcommand vendor" -l sync -d 'Additional `Cargo.toml` to sync and vendor' -r -F
 complete -c x -n "__fish_x_using_subcommand vendor" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand vendor" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand vendor" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand vendor" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand vendor" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand vendor" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand vendor" -l exclude -d 'build paths to exclude' -r -F
@@ -674,7 +674,7 @@ complete -c x -n "__fish_x_using_subcommand vendor" -l skip-std-check-if-no-down
 complete -c x -n "__fish_x_using_subcommand vendor" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l exclude -d 'build paths to exclude' -r -F
@@ -718,7 +718,7 @@ complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_fro
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l skip -d 'build paths to skip' -r -F
@@ -756,7 +756,7 @@ complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_fro
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from samply" -l skip -d 'build paths to skip' -r -F
@@ -794,7 +794,7 @@ complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_fro
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l skip -d 'build paths to skip' -r -F
@@ -832,7 +832,7 @@ complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_fro
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l skip -d 'build paths to skip' -r -F
@@ -866,7 +866,7 @@ complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_fro
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l host -d 'host targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l target -d 'target targets to build' -r -f
 complete -c x -n "__fish_x_using_subcommand perf; and __fish_seen_subcommand_from compare" -l exclude -d 'build paths to exclude' -r -F
diff --git a/src/etc/completions/x.ps1 b/src/etc/completions/x.ps1
index 23d8fe0cdd3e7..a891a9db33211 100644
--- a/src/etc/completions/x.ps1
+++ b/src/etc/completions/x.ps1
@@ -23,7 +23,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -82,7 +82,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;build' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -124,7 +124,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;check' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -171,7 +171,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('-F', '-F ', [CompletionResultType]::ParameterName, 'clippy lints to forbid')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -216,7 +216,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;fix' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -258,7 +258,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;fmt' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -302,7 +302,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;doc' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -352,7 +352,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--run', '--run', [CompletionResultType]::ParameterName, 'whether to execute run-* tests')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -403,7 +403,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--test-args', '--test-args', [CompletionResultType]::ParameterName, 'extra arguments to be passed for the test tool being used (e.g. libtest, compiletest or rustdoc)')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -449,7 +449,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--test-args', '--test-args', [CompletionResultType]::ParameterName, 'test-args')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -492,7 +492,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--stage', '--stage', [CompletionResultType]::ParameterName, 'Clean a specific stage without touching other artifacts. By default, every stage is cleaned if this option is not used')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -534,7 +534,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;dist' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -576,7 +576,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;install' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -619,7 +619,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--args', '--args', [CompletionResultType]::ParameterName, 'arguments for the tool')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -661,7 +661,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;setup' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -703,7 +703,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;suggest' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -747,7 +747,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--sync', '--sync', [CompletionResultType]::ParameterName, 'Additional `Cargo.toml` to sync and vendor')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -790,7 +790,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;perf' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -841,7 +841,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -886,7 +886,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -931,7 +931,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -976,7 +976,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -1017,7 +1017,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
         'x;perf;compare' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
diff --git a/src/etc/completions/x.py.fish b/src/etc/completions/x.py.fish
index 1fc5bb12cfb17..e6326fcb0bb82 100644
--- a/src/etc/completions/x.py.fish
+++ b/src/etc/completions/x.py.fish
@@ -26,7 +26,7 @@ end
 
 complete -c x.py -n "__fish_x.py_needs_command" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_needs_command" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_needs_command" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_needs_command" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_needs_command" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_needs_command" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_needs_command" -l exclude -d 'build paths to exclude' -r -F
@@ -78,7 +78,7 @@ complete -c x.py -n "__fish_x.py_needs_command" -a "vendor" -d 'Vendor dependenc
 complete -c x.py -n "__fish_x.py_needs_command" -a "perf" -d 'Perform profiling and benchmarking of the compiler using `rustc-perf`'
 complete -c x.py -n "__fish_x.py_using_subcommand build" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand build" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand build" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand build" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand build" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand build" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand build" -l exclude -d 'build paths to exclude' -r -F
@@ -113,7 +113,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand build" -l skip-std-check-if-no
 complete -c x.py -n "__fish_x.py_using_subcommand build" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand check" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand check" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand check" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand check" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand check" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand check" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand check" -l exclude -d 'build paths to exclude' -r -F
@@ -153,7 +153,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand clippy" -s W -d 'clippy lints
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -s F -d 'clippy lints to forbid' -r
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l exclude -d 'build paths to exclude' -r -F
@@ -191,7 +191,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand clippy" -l skip-std-check-if-n
 complete -c x.py -n "__fish_x.py_using_subcommand clippy" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand fix" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand fix" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand fix" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand fix" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand fix" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand fix" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand fix" -l exclude -d 'build paths to exclude' -r -F
@@ -226,7 +226,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand fix" -l skip-std-check-if-no-d
 complete -c x.py -n "__fish_x.py_using_subcommand fix" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l exclude -d 'build paths to exclude' -r -F
@@ -263,7 +263,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand fmt" -l skip-std-check-if-no-d
 complete -c x.py -n "__fish_x.py_using_subcommand fmt" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand doc" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand doc" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand doc" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand doc" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand doc" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand doc" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand doc" -l exclude -d 'build paths to exclude' -r -F
@@ -306,7 +306,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand test" -l pass -d 'force {check
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l run -d 'whether to execute run-* tests' -r
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand test" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand test" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l exclude -d 'build paths to exclude' -r -F
@@ -350,7 +350,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand test" -s h -l help -d 'Print h
 complete -c x.py -n "__fish_x.py_using_subcommand miri" -l test-args -d 'extra arguments to be passed for the test tool being used (e.g. libtest, compiletest or rustdoc)' -r
 complete -c x.py -n "__fish_x.py_using_subcommand miri" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand miri" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand miri" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand miri" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand miri" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand miri" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand miri" -l exclude -d 'build paths to exclude' -r -F
@@ -389,7 +389,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand miri" -s h -l help -d 'Print h
 complete -c x.py -n "__fish_x.py_using_subcommand bench" -l test-args -r
 complete -c x.py -n "__fish_x.py_using_subcommand bench" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand bench" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand bench" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand bench" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand bench" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand bench" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand bench" -l exclude -d 'build paths to exclude' -r -F
@@ -425,7 +425,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand bench" -s h -l help -d 'Print
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -l stage -d 'Clean a specific stage without touching other artifacts. By default, every stage is cleaned if this option is not used' -r
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand clean" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand clean" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -l exclude -d 'build paths to exclude' -r -F
@@ -460,7 +460,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand clean" -l skip-std-check-if-no
 complete -c x.py -n "__fish_x.py_using_subcommand clean" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand dist" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand dist" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand dist" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand dist" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand dist" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand dist" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand dist" -l exclude -d 'build paths to exclude' -r -F
@@ -495,7 +495,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand dist" -l skip-std-check-if-no-
 complete -c x.py -n "__fish_x.py_using_subcommand dist" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand install" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand install" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand install" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand install" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand install" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand install" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand install" -l exclude -d 'build paths to exclude' -r -F
@@ -531,7 +531,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand install" -s h -l help -d 'Prin
 complete -c x.py -n "__fish_x.py_using_subcommand run" -l args -d 'arguments for the tool' -r
 complete -c x.py -n "__fish_x.py_using_subcommand run" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand run" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand run" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand run" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand run" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand run" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand run" -l exclude -d 'build paths to exclude' -r -F
@@ -566,7 +566,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand run" -l skip-std-check-if-no-d
 complete -c x.py -n "__fish_x.py_using_subcommand run" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand setup" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand setup" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand setup" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand setup" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand setup" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand setup" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand setup" -l exclude -d 'build paths to exclude' -r -F
@@ -601,7 +601,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand setup" -l skip-std-check-if-no
 complete -c x.py -n "__fish_x.py_using_subcommand setup" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand suggest" -l exclude -d 'build paths to exclude' -r -F
@@ -638,7 +638,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand suggest" -s h -l help -d 'Prin
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l sync -d 'Additional `Cargo.toml` to sync and vendor' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l exclude -d 'build paths to exclude' -r -F
@@ -674,7 +674,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand vendor" -l skip-std-check-if-n
 complete -c x.py -n "__fish_x.py_using_subcommand vendor" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and not __fish_seen_subcommand_from eprintln samply cachegrind benchmark compare" -l exclude -d 'build paths to exclude' -r -F
@@ -718,7 +718,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcomma
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from eprintln" -l skip -d 'build paths to skip' -r -F
@@ -756,7 +756,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcomma
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from samply" -l skip -d 'build paths to skip' -r -F
@@ -794,7 +794,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcomma
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from cachegrind" -l skip -d 'build paths to skip' -r -F
@@ -832,7 +832,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcomma
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l profiles -d 'Select the profiles that should be benchmarked' -r -f -a "{Check\t'',Debug\t'',Doc\t'',Opt\t'',Clippy\t''}"
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -l skip -d 'build paths to skip' -r -F
@@ -866,7 +866,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcomma
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from benchmark" -s h -l help -d 'Print help (see more with \'--help\')'
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
-complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l build -d 'build target of the stage0 compiler' -r -f
+complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l build -d 'host target of the stage0 compiler' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l host -d 'host targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l target -d 'target targets to build' -r -f
 complete -c x.py -n "__fish_x.py_using_subcommand perf; and __fish_seen_subcommand_from compare" -l exclude -d 'build paths to exclude' -r -F
diff --git a/src/etc/completions/x.py.ps1 b/src/etc/completions/x.py.ps1
index 5d224ac6df4ad..ee3373b9e75b0 100644
--- a/src/etc/completions/x.py.ps1
+++ b/src/etc/completions/x.py.ps1
@@ -23,7 +23,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -82,7 +82,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;build' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -124,7 +124,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;check' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -171,7 +171,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('-F', '-F ', [CompletionResultType]::ParameterName, 'clippy lints to forbid')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -216,7 +216,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;fix' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -258,7 +258,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;fmt' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -302,7 +302,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;doc' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -352,7 +352,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--run', '--run', [CompletionResultType]::ParameterName, 'whether to execute run-* tests')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -403,7 +403,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--test-args', '--test-args', [CompletionResultType]::ParameterName, 'extra arguments to be passed for the test tool being used (e.g. libtest, compiletest or rustdoc)')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -449,7 +449,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--test-args', '--test-args', [CompletionResultType]::ParameterName, 'test-args')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -492,7 +492,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--stage', '--stage', [CompletionResultType]::ParameterName, 'Clean a specific stage without touching other artifacts. By default, every stage is cleaned if this option is not used')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -534,7 +534,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;dist' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -576,7 +576,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;install' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -619,7 +619,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--args', '--args', [CompletionResultType]::ParameterName, 'arguments for the tool')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -661,7 +661,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;setup' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -703,7 +703,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;suggest' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -747,7 +747,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--sync', '--sync', [CompletionResultType]::ParameterName, 'Additional `Cargo.toml` to sync and vendor')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -790,7 +790,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;perf' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
@@ -841,7 +841,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -886,7 +886,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -931,7 +931,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -976,7 +976,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--profiles', '--profiles', [CompletionResultType]::ParameterName, 'Select the profiles that should be benchmarked')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--skip', '--skip', [CompletionResultType]::ParameterName, 'build paths to skip')
@@ -1017,7 +1017,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
         'x.py;perf;compare' {
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
-            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'build target of the stage0 compiler')
+            [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
             [CompletionResult]::new('--host', '--host', [CompletionResultType]::ParameterName, 'host targets to build')
             [CompletionResult]::new('--target', '--target', [CompletionResultType]::ParameterName, 'target targets to build')
             [CompletionResult]::new('--exclude', '--exclude', [CompletionResultType]::ParameterName, 'build paths to exclude')
diff --git a/src/etc/completions/x.py.zsh b/src/etc/completions/x.py.zsh
index bc55280d03894..6dc0570819950 100644
--- a/src/etc/completions/x.py.zsh
+++ b/src/etc/completions/x.py.zsh
@@ -17,7 +17,7 @@ _x.py() {
     _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -69,7 +69,7 @@ _x.py() {
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -113,7 +113,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -162,7 +162,7 @@ _arguments "${_arguments_options[@]}" : \
 '*-F+[clippy lints to forbid]:LINT:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -209,7 +209,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -253,7 +253,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -299,7 +299,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -351,7 +351,7 @@ _arguments "${_arguments_options[@]}" : \
 '--run=[whether to execute run-* tests]:auto | always | never:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -404,7 +404,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--test-args=[extra arguments to be passed for the test tool being used (e.g. libtest, compiletest or rustdoc)]:ARGS:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -452,7 +452,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--test-args=[]:TEST_ARGS:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -497,7 +497,7 @@ _arguments "${_arguments_options[@]}" : \
 '--stage=[Clean a specific stage without touching other artifacts. By default, every stage is cleaned if this option is not used]:N:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -541,7 +541,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -585,7 +585,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -630,7 +630,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--args=[arguments for the tool]:ARGS:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -674,7 +674,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -719,7 +719,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -765,7 +765,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--sync=[Additional \`Cargo.toml\` to sync and vendor]:SYNC:_files' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -810,7 +810,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -867,7 +867,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -914,7 +914,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -961,7 +961,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -1008,7 +1008,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -1052,7 +1052,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
diff --git a/src/etc/completions/x.zsh b/src/etc/completions/x.zsh
index 2e3094fc379d0..869884bf1dcd2 100644
--- a/src/etc/completions/x.zsh
+++ b/src/etc/completions/x.zsh
@@ -17,7 +17,7 @@ _x() {
     _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -69,7 +69,7 @@ _x() {
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -113,7 +113,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -162,7 +162,7 @@ _arguments "${_arguments_options[@]}" : \
 '*-F+[clippy lints to forbid]:LINT:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -209,7 +209,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -253,7 +253,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -299,7 +299,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -351,7 +351,7 @@ _arguments "${_arguments_options[@]}" : \
 '--run=[whether to execute run-* tests]:auto | always | never:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -404,7 +404,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--test-args=[extra arguments to be passed for the test tool being used (e.g. libtest, compiletest or rustdoc)]:ARGS:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -452,7 +452,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--test-args=[]:TEST_ARGS:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -497,7 +497,7 @@ _arguments "${_arguments_options[@]}" : \
 '--stage=[Clean a specific stage without touching other artifacts. By default, every stage is cleaned if this option is not used]:N:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -541,7 +541,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -585,7 +585,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -630,7 +630,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--args=[arguments for the tool]:ARGS:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -674,7 +674,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -719,7 +719,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -765,7 +765,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--sync=[Additional \`Cargo.toml\` to sync and vendor]:SYNC:_files' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -810,7 +810,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \
@@ -867,7 +867,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -914,7 +914,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -961,7 +961,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -1008,7 +1008,7 @@ _arguments "${_arguments_options[@]}" : \
 '*--profiles=[Select the profiles that should be benchmarked]:PROFILES:(Check Debug Doc Opt Clippy)' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--skip=[build paths to skip]:PATH:_files' \
@@ -1052,7 +1052,7 @@ _arguments "${_arguments_options[@]}" : \
 _arguments "${_arguments_options[@]}" : \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
-'--build=[build target of the stage0 compiler]:BUILD:' \
+'--build=[host target of the stage0 compiler]:BUILD:' \
 '--host=[host targets to build]:HOST:' \
 '--target=[target targets to build]:TARGET:' \
 '*--exclude=[build paths to exclude]:PATH:_files' \