Consolidate stage directories and group logs in bootstrap

src/bootstrap/src/bin/rustc.rs

@@ -258,7 +258,7 @@ fn main() {
         eprintln!("{prefix} libdir: {libdir:?}");
     }
 
-    maybe_dump(format!("stage{stage}-rustc"), &cmd);
+    maybe_dump(format!("stage{}-rustc", stage + 1), &cmd);
 
     let start = Instant::now();
     let (child, status) = {

src/bootstrap/src/bin/rustdoc.rs

@@ -56,11 +56,11 @@ fn main() {
     // Thus, if we are on stage 0, we explicitly set `--cfg=bootstrap`.
     // We also declare that the flag is expected, which we need to do to not
     // get warnings about it being unexpected.
-    if stage == "0" {
+    if stage == 0 {
         cmd.arg("--cfg=bootstrap");
     }
 
-    maybe_dump(format!("stage{stage}-rustdoc"), &cmd);
+    maybe_dump(format!("stage{}-rustdoc", stage + 1), &cmd);
 
     if verbose > 1 {
         eprintln!(

src/bootstrap/src/core/build_steps/clean.rs

@@ -129,7 +129,7 @@ fn clean_specific_stage(build: &Build, stage: u32) {
 
         for entry in entries {
             let entry = t!(entry);
-            let stage_prefix = format!("stage{stage}");
+            let stage_prefix = format!("stage{}", stage + 1);
 
             // if current entry is not related with the target stage, continue
             if !entry.file_name().to_str().unwrap_or("").contains(&stage_prefix) {

src/bootstrap/src/core/build_steps/tool.rs

@@ -380,13 +380,13 @@ pub(crate) fn get_tool_target_compiler(
 /// tools directory.
 fn copy_link_tool_bin(
     builder: &Builder<'_>,
-    compiler: Compiler,
+    build_compiler: Compiler,
     target: TargetSelection,
     mode: Mode,
     name: &str,
 ) -> PathBuf {
-    let cargo_out = builder.cargo_out(compiler, mode, target).join(exe(name, target));
-    let bin = builder.tools_dir(compiler).join(exe(name, target));
+    let cargo_out = builder.cargo_out(build_compiler, mode, target).join(exe(name, target));
+    let bin = builder.tools_dir(build_compiler).join(exe(name, target));
     builder.copy_link(&cargo_out, &bin, FileType::Executable);
     bin
 }

src/bootstrap/src/lib.rs

@@ -859,14 +859,17 @@ impl Build {
         if self.config.rust_optimize.is_release() { "release" } else { "debug" }
     }
 
-    fn tools_dir(&self, compiler: Compiler) -> PathBuf {
-        let out = self.out.join(compiler.host).join(format!("stage{}-tools-bin", compiler.stage));
+    fn tools_dir(&self, build_compiler: Compiler) -> PathBuf {
+        let out = self
+            .out
+            .join(build_compiler.host)
+            .join(format!("stage{}-tools-bin", build_compiler.stage + 1));
         t!(fs::create_dir_all(&out));
         out
     }
 
     /// Returns the root directory for all output generated in a particular
-    /// stage when running with a particular host compiler.
+    /// stage when being built with a particular build compiler.
     ///
     /// The mode indicates what the root directory is for.
     fn stage_out(&self, build_compiler: Compiler, mode: Mode) -> PathBuf {
@@ -876,15 +879,17 @@ impl Build {
             (None, "bootstrap-tools")
         }
         fn staged_tool(build_compiler: Compiler) -> (Option<u32>, &'static str) {
-            (Some(build_compiler.stage), "tools")
+            (Some(build_compiler.stage + 1), "tools")
         }
 
         let (stage, suffix) = match mode {
+            // Std is special, stage N std is built with stage N rustc
             Mode::Std => (Some(build_compiler.stage), "std"),
-            Mode::Rustc => (Some(build_compiler.stage), "rustc"),
-            Mode::Codegen => (Some(build_compiler.stage), "codegen"),
+            // The rest of things are built with stage N-1 rustc
+            Mode::Rustc => (Some(build_compiler.stage + 1), "rustc"),
+            Mode::Codegen => (Some(build_compiler.stage + 1), "codegen"),
             Mode::ToolBootstrap => bootstrap_tool(),
-            Mode::ToolStd | Mode::ToolRustc => (Some(build_compiler.stage), "tools"),
+            Mode::ToolStd | Mode::ToolRustc => (Some(build_compiler.stage + 1), "tools"),
             Mode::ToolTarget => {
                 // If we're not cross-compiling (the common case), share the target directory with
                 // bootstrap tools to reuse the build cache.
@@ -907,8 +912,8 @@ impl Build {
     /// Returns the root output directory for all Cargo output in a given stage,
     /// running a particular compiler, whether or not we're building the
     /// standard library, and targeting the specified architecture.
-    fn cargo_out(&self, compiler: Compiler, mode: Mode, target: TargetSelection) -> PathBuf {
-        self.stage_out(compiler, mode).join(target).join(self.cargo_dir())
+    fn cargo_out(&self, build_compiler: Compiler, mode: Mode, target: TargetSelection) -> PathBuf {
+        self.stage_out(build_compiler, mode).join(target).join(self.cargo_dir())
     }
 
     /// Root output directory of LLVM for `target`

src/bootstrap/src/utils/shared_helpers.rs

@@ -81,10 +81,11 @@ pub fn parse_rustc_verbose() -> usize {
 }
 
 /// Parses the value of the "RUSTC_STAGE" environment variable and returns it as a `String`.
+/// This is the stage of the *build compiler*, which we are wrapping using a rustc/rustdoc wrapper.
 ///
 /// If "RUSTC_STAGE" was not set, the program will be terminated with 101.
-pub fn parse_rustc_stage() -> String {
-    env::var("RUSTC_STAGE").unwrap_or_else(|_| {
+pub fn parse_rustc_stage() -> u32 {
+    env::var("RUSTC_STAGE").ok().and_then(|v| v.parse().ok()).unwrap_or_else(|| {
         // Don't panic here; it's reasonable to try and run these shims directly. Give a helpful error instead.
         eprintln!("rustc shim: FATAL: RUSTC_STAGE was not set");
         eprintln!("rustc shim: NOTE: use `x.py build -vvv` to see all environment variables set by bootstrap");