[do not merge] CI experiments

README.md

@@ -21,6 +21,8 @@ standard library, and documentation.
 
 ## Why Rust?
 
+PERF! PERF! PERF!
+
 - **Performance:** Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrated with other languages.
 
 - **Reliability:** Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.

src/bootstrap/src/core/build_steps/check.rs

@@ -116,7 +116,7 @@ impl Step for Std {
         );
 
         let stamp = build_stamp::libstd_stamp(builder, compiler, target).with_prefix("check");
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
 
         // We skip populating the sysroot in non-zero stage because that'll lead
         // to rlib/rmeta conflicts if std gets built during this session.
@@ -165,7 +165,7 @@ impl Step for Std {
 
         let stamp = build_stamp::libstd_stamp(builder, compiler, target).with_prefix("check-test");
         let _guard = builder.msg_check("library test/bench/example targets", target, Some(stage));
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
     }
 }
 
@@ -252,7 +252,7 @@ impl Step for Rustc {
 
         let stamp = build_stamp::librustc_stamp(builder, compiler, target).with_prefix("check");
 
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
 
         let libdir = builder.sysroot_target_libdir(compiler, target);
         let hostdir = builder.sysroot_target_libdir(compiler, compiler.host);
@@ -313,7 +313,7 @@ impl Step for CodegenBackend {
         let stamp = build_stamp::codegen_backend_stamp(builder, compiler, target, backend)
             .with_prefix("check");
 
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
     }
 }
 
@@ -371,7 +371,7 @@ impl Step for RustAnalyzer {
             .with_prefix("rust-analyzer-check");
 
         let _guard = builder.msg_check("rust-analyzer artifacts", target, None);
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
     }
 }
 
@@ -430,7 +430,7 @@ impl Step for Compiletest {
             .with_prefix("compiletest-check");
 
         let _guard = builder.msg_check("compiletest artifacts", self.target, None);
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
     }
 }
 
@@ -504,7 +504,7 @@ fn run_tool_check_step(
         .with_prefix(&format!("{}-check", step_type_name.to_lowercase()));
 
     let _guard = builder.msg_check(format!("{display_name} artifacts"), target, None);
-    run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+    run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
 }
 
 tool_check_step!(Rustdoc { path: "src/tools/rustdoc", alt_path: "src/librustdoc" });
@@ -589,6 +589,6 @@ impl Step for CoverageDump {
             &compiler.host,
             &target,
         );
-        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
+        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], false);
     }
 }

src/bootstrap/src/core/build_steps/clippy.rs

@@ -168,7 +168,6 @@ impl Step for Std {
             lint_args(builder, &self.config, IGNORED_RULES_FOR_STD_AND_RUSTC),
             &build_stamp::libstd_stamp(builder, compiler, target),
             vec![],
-            true,
             false,
         );
     }
@@ -246,7 +245,6 @@ impl Step for Rustc {
             lint_args(builder, &self.config, IGNORED_RULES_FOR_STD_AND_RUSTC),
             &build_stamp::librustc_stamp(builder, compiler, target),
             vec![],
-            true,
             false,
         );
     }
@@ -320,7 +318,6 @@ macro_rules! lint_any {
                     lint_args(builder, &self.config, &[]),
                     &stamp,
                     vec![],
-                    true,
                     false,
                 );
             }

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

@@ -295,7 +295,6 @@ impl Step for Std {
             vec![],
             &build_stamp::libstd_stamp(builder, compiler, target),
             target_deps,
-            self.is_for_mir_opt_tests, // is_check
             false,
         );
 
@@ -609,6 +608,8 @@ pub fn std_cargo(builder: &Builder<'_>, target: TargetSelection, stage: u32, car
         features += "compiler-builtins-no-f16-f128 ";
     }
 
+    cargo.arg("-Zno-embed-metadata");
+
     if builder.no_std(target) == Some(true) {
         features += " compiler-builtins-mem";
         if !target.starts_with("bpf") {
@@ -1154,7 +1155,6 @@ impl Step for Rustc {
             vec![],
             &stamp,
             vec![],
-            false,
             true, // Only ship rustc_driver.so and .rmeta files, not all intermediate .rlib files.
         );
 
@@ -1208,6 +1208,7 @@ pub fn rustc_cargo(
         .arg(builder.src.join("compiler/rustc/Cargo.toml"));
 
     cargo.rustdocflag("-Zcrate-attr=warn(rust_2018_idioms)");
+    cargo.arg("-Zno-embed-metadata");
 
     // If the rustc output is piped to e.g. `head -n1` we want the process to be killed, rather than
     // having an error bubble up and cause a panic.
@@ -1691,7 +1692,7 @@ impl Step for CodegenBackend {
         let tmp_stamp = BuildStamp::new(&out_dir).with_prefix("tmp");
 
         let _guard = builder.msg_build(compiler, format_args!("codegen backend {backend}"), target);
-        let files = run_cargo(builder, cargo, vec![], &tmp_stamp, vec![], false, false);
+        let files = run_cargo(builder, cargo, vec![], &tmp_stamp, vec![], false);
         if builder.config.dry_run() {
             return;
         }
@@ -2341,7 +2342,6 @@ pub fn run_cargo(
     tail_args: Vec<String>,
     stamp: &BuildStamp,
     additional_target_deps: Vec<(PathBuf, DependencyType)>,
-    is_check: bool,
     rlib_only_metadata: bool,
 ) -> Vec<PathBuf> {
     // `target_root_dir` looks like $dir/$target/release
@@ -2381,7 +2381,7 @@ pub fn run_cargo(
                 // Always keep native libraries, rust dylibs and debuginfo
                 keep = true;
             }
-            if is_check && filename.ends_with(".rmeta") {
+            if filename.ends_with(".rmeta") {
                 // During check builds we need to keep crate metadata
                 keep = true;
             } else if rlib_only_metadata {

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

@@ -2227,7 +2227,7 @@ impl BookTest {
                 let stamp = BuildStamp::new(&builder.cargo_out(compiler, mode, target))
                     .with_prefix(PathBuf::from(dep).file_name().and_then(|v| v.to_str()).unwrap());
 
-                let output_paths = run_cargo(builder, cargo, vec![], &stamp, vec![], false, false);
+                let output_paths = run_cargo(builder, cargo, vec![], &stamp, vec![], false);
                 let directories = output_paths
                     .into_iter()
                     .filter_map(|p| p.parent().map(ToOwned::to_owned))