replace bootstrap-self-test feature flag with cfg(test)

src/bootstrap/Cargo.toml

@@ -7,7 +7,6 @@ default-run = "bootstrap"
 
 [features]
 build-metrics = ["sysinfo"]
-bootstrap-self-test = [] # enabled in the bootstrap unit tests
 
 [lib]
 path = "src/lib.rs"

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

@@ -417,7 +417,7 @@ fn copy_self_contained_objects(
 /// Resolves standard library crates for `Std::run_make` for any build kind (like check, build, clippy, etc.).
 pub fn std_crates_for_run_make(run: &RunConfig<'_>) -> Vec<String> {
     // FIXME: Extend builder tests to cover the `crates` field of `Std` instances.
-    if cfg!(feature = "bootstrap-self-test") {
+    if cfg!(test) {
         return vec![];
     }
 

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

@@ -3148,9 +3148,8 @@ impl Step for Bootstrap {
 
         let mut cmd = command(&builder.initial_cargo);
         cmd.arg("test")
-            .args(["--features", "bootstrap-self-test"])
             .current_dir(builder.src.join("src/bootstrap"))
-            .env("RUSTFLAGS", "-Cdebuginfo=2")
+            .env("RUSTFLAGS", "--cfg test -Cdebuginfo=2")
             .env("CARGO_TARGET_DIR", builder.out.join("bootstrap"))
             .env("RUSTC_BOOTSTRAP", "1")
             .env("RUSTDOC", builder.rustdoc(compiler))

src/bootstrap/src/core/config/config.rs

@@ -1441,7 +1441,7 @@ impl Config {
         // Give a hard error if `--config` or `RUST_BOOTSTRAP_CONFIG` are set to a missing path,
         // but not if `config.toml` hasn't been created.
         let mut toml = if !using_default_path || toml_path.exists() {
-            config.config = Some(if cfg!(not(feature = "bootstrap-self-test")) {
+            config.config = Some(if cfg!(not(test)) {
                 toml_path.canonicalize().unwrap()
             } else {
                 toml_path.clone()
@@ -2793,11 +2793,11 @@ impl Config {
         }
     }
 
-    #[cfg(feature = "bootstrap-self-test")]
+    #[cfg(test)]
     pub fn check_stage0_version(&self, _program_path: &Path, _component_name: &'static str) {}
 
     /// check rustc/cargo version is same or lower with 1 apart from the building one
-    #[cfg(not(feature = "bootstrap-self-test"))]
+    #[cfg(not(test))]
     pub fn check_stage0_version(&self, program_path: &Path, component_name: &'static str) {
         use build_helper::util::fail;
 
@@ -2939,7 +2939,7 @@ impl Config {
             }
 
             // Fetching the LLVM submodule is unnecessary for self-tests.
-            #[cfg(not(feature = "bootstrap-self-test"))]
+            #[cfg(not(test))]
             self.update_submodule("src/llvm-project");
 
             // Check for untracked changes in `src/llvm-project`.
@@ -3014,7 +3014,7 @@ impl Config {
 
 /// Compares the current `Llvm` options against those in the CI LLVM builder and detects any incompatible options.
 /// It does this by destructuring the `Llvm` instance to make sure every `Llvm` field is covered and not missing.
-#[cfg(not(feature = "bootstrap-self-test"))]
+#[cfg(not(test))]
 pub(crate) fn check_incompatible_options_for_ci_llvm(
     current_config_toml: TomlConfig,
     ci_config_toml: TomlConfig,

src/bootstrap/src/core/download.rs

@@ -444,14 +444,14 @@ impl Config {
         cargo_clippy
     }
 
-    #[cfg(feature = "bootstrap-self-test")]
+    #[cfg(test)]
     pub(crate) fn maybe_download_rustfmt(&self) -> Option<PathBuf> {
         None
     }
 
     /// NOTE: rustfmt is a completely different toolchain than the bootstrap compiler, so it can't
     /// reuse target directories or artifacts
-    #[cfg(not(feature = "bootstrap-self-test"))]
+    #[cfg(not(test))]
     pub(crate) fn maybe_download_rustfmt(&self) -> Option<PathBuf> {
         use build_helper::stage0_parser::VersionMetadata;
 
@@ -534,10 +534,10 @@ impl Config {
         );
     }
 
-    #[cfg(feature = "bootstrap-self-test")]
+    #[cfg(test)]
     pub(crate) fn download_beta_toolchain(&self) {}
 
-    #[cfg(not(feature = "bootstrap-self-test"))]
+    #[cfg(not(test))]
     pub(crate) fn download_beta_toolchain(&self) {
         self.verbose(|| println!("downloading stage0 beta artifacts"));
 
@@ -714,10 +714,10 @@ download-rustc = false
         self.unpack(&tarball, &bin_root, prefix);
     }
 
-    #[cfg(feature = "bootstrap-self-test")]
+    #[cfg(test)]
     pub(crate) fn maybe_download_ci_llvm(&self) {}
 
-    #[cfg(not(feature = "bootstrap-self-test"))]
+    #[cfg(not(test))]
     pub(crate) fn maybe_download_ci_llvm(&self) {
         use build_helper::exit;
 
@@ -789,7 +789,7 @@ download-rustc = false
         };
     }
 
-    #[cfg(not(feature = "bootstrap-self-test"))]
+    #[cfg(not(test))]
     fn download_ci_llvm(&self, llvm_sha: &str) {
         let llvm_assertions = self.llvm_assertions;
 

src/bootstrap/src/core/sanity.rs

@@ -14,10 +14,10 @@ use std::path::PathBuf;
 use std::{env, fs};
 
 use crate::Build;
-#[cfg(not(feature = "bootstrap-self-test"))]
+#[cfg(not(test))]
 use crate::builder::Builder;
 use crate::builder::Kind;
-#[cfg(not(feature = "bootstrap-self-test"))]
+#[cfg(not(test))]
 use crate::core::build_steps::tool;
 use crate::core::config::Target;
 use crate::utils::exec::command;
@@ -38,7 +38,7 @@ const STAGE0_MISSING_TARGETS: &[&str] = &[
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM
 /// from CI (with`llvm.download-ci-llvm` option).
-#[cfg(not(feature = "bootstrap-self-test"))]
+#[cfg(not(test))]
 const LIBSTDCXX_MIN_VERSION_THRESHOLD: usize = 8;
 
 impl Finder {
@@ -106,7 +106,7 @@ 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(feature = "bootstrap-self-test"))]
+    #[cfg(not(test))]
     if !build.config.dry_run() && !build.build.is_msvc() && build.config.llvm_from_ci {
         let builder = Builder::new(build);
         let libcxx_version = builder.ensure(tool::LibcxxVersionTool { target: build.build });
@@ -226,8 +226,7 @@ than building it.
         }
 
         // Ignore fake targets that are only used for unit tests in bootstrap.
-        if cfg!(not(feature = "bootstrap-self-test")) && !skip_target_sanity && !build.local_rebuild
-        {
+        if cfg!(not(test)) && !skip_target_sanity && !build.local_rebuild {
             let mut has_target = false;
             let target_str = target.to_string();