Rollup of 5 pull requests

library/alloc/src/collections/btree/map.rs

@@ -2921,7 +2921,7 @@ impl<'a, K, V> Cursor<'a, K, V> {
     /// Returns a reference to the key and value of the next element without
     /// moving the cursor.
     ///
-    /// If the cursor is at the end of the map then `None` is returned
+    /// If the cursor is at the end of the map then `None` is returned.
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn peek_next(&self) -> Option<(&'a K, &'a V)> {
         self.clone().next()
@@ -2963,7 +2963,7 @@ impl<'a, K, V, A> CursorMut<'a, K, V, A> {
     /// Returns a reference to the key and value of the next element without
     /// moving the cursor.
     ///
-    /// If the cursor is at the end of the map then `None` is returned
+    /// If the cursor is at the end of the map then `None` is returned.
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn peek_next(&mut self) -> Option<(&K, &mut V)> {
         let (k, v) = self.inner.peek_next()?;
@@ -3061,7 +3061,7 @@ impl<'a, K, V, A> CursorMutKey<'a, K, V, A> {
     /// Returns a reference to the key and value of the next element without
     /// moving the cursor.
     ///
-    /// If the cursor is at the end of the map then `None` is returned
+    /// If the cursor is at the end of the map then `None` is returned.
     #[unstable(feature = "btree_cursors", issue = "107540")]
     pub fn peek_next(&mut self) -> Option<(&mut K, &mut V)> {
         let current = self.current.as_mut()?;

library/std/src/io/cursor.rs

@@ -209,55 +209,60 @@ impl<T> Cursor<T>
 where
     T: AsRef<[u8]>,
 {
-    /// Returns the remaining slice.
+    /// Splits the underlying slice at the cursor position and returns them.
     ///
     /// # Examples
     ///
     /// ```
-    /// #![feature(cursor_remaining)]
+    /// #![feature(cursor_split)]
     /// use std::io::Cursor;
     ///
     /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
     ///
-    /// assert_eq!(buff.remaining_slice(), &[1, 2, 3, 4, 5]);
+    /// assert_eq!(buff.split(), ([].as_slice(), [1, 2, 3, 4, 5].as_slice()));
     ///
     /// buff.set_position(2);
-    /// assert_eq!(buff.remaining_slice(), &[3, 4, 5]);
-    ///
-    /// buff.set_position(4);
-    /// assert_eq!(buff.remaining_slice(), &[5]);
+    /// assert_eq!(buff.split(), ([1, 2].as_slice(), [3, 4, 5].as_slice()));
     ///
     /// buff.set_position(6);
-    /// assert_eq!(buff.remaining_slice(), &[]);
+    /// assert_eq!(buff.split(), ([1, 2, 3, 4, 5].as_slice(), [].as_slice()));
     /// ```
-    #[unstable(feature = "cursor_remaining", issue = "86369")]
-    pub fn remaining_slice(&self) -> &[u8] {
-        let len = self.pos.min(self.inner.as_ref().len() as u64);
-        &self.inner.as_ref()[(len as usize)..]
+    #[unstable(feature = "cursor_split", issue = "86369")]
+    pub fn split(&self) -> (&[u8], &[u8]) {
+        let slice = self.inner.as_ref();
+        let pos = self.pos.min(slice.len() as u64);
+        slice.split_at(pos as usize)
     }
+}
 
-    /// Returns `true` if the remaining slice is empty.
+impl<T> Cursor<T>
+where
+    T: AsMut<[u8]>,
+{
+    /// Splits the underlying slice at the cursor position and returns them
+    /// mutably.
     ///
     /// # Examples
     ///
     /// ```
-    /// #![feature(cursor_remaining)]
+    /// #![feature(cursor_split)]
     /// use std::io::Cursor;
     ///
     /// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
     ///
-    /// buff.set_position(2);
-    /// assert!(!buff.is_empty());
+    /// assert_eq!(buff.split_mut(), ([].as_mut_slice(), [1, 2, 3, 4, 5].as_mut_slice()));
     ///
-    /// buff.set_position(5);
-    /// assert!(buff.is_empty());
+    /// buff.set_position(2);
+    /// assert_eq!(buff.split_mut(), ([1, 2].as_mut_slice(), [3, 4, 5].as_mut_slice()));
     ///
-    /// buff.set_position(10);
-    /// assert!(buff.is_empty());
+    /// buff.set_position(6);
+    /// assert_eq!(buff.split_mut(), ([1, 2, 3, 4, 5].as_mut_slice(), [].as_mut_slice()));
     /// ```
-    #[unstable(feature = "cursor_remaining", issue = "86369")]
-    pub fn is_empty(&self) -> bool {
-        self.pos >= self.inner.as_ref().len() as u64
+    #[unstable(feature = "cursor_split", issue = "86369")]
+    pub fn split_mut(&mut self) -> (&mut [u8], &mut [u8]) {
+        let slice = self.inner.as_mut();
+        let pos = self.pos.min(slice.len() as u64);
+        slice.split_at_mut(pos as usize)
     }
 }
 
@@ -319,15 +324,15 @@ where
     T: AsRef<[u8]>,
 {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let n = Read::read(&mut self.remaining_slice(), buf)?;
+        let n = Read::read(&mut Cursor::split(self).1, buf)?;
         self.pos += n as u64;
         Ok(n)
     }
 
     fn read_buf(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
         let prev_written = cursor.written();
 
-        Read::read_buf(&mut self.remaining_slice(), cursor.reborrow())?;
+        Read::read_buf(&mut Cursor::split(self).1, cursor.reborrow())?;
 
         self.pos += (cursor.written() - prev_written) as u64;
 
@@ -351,7 +356,7 @@ where
     }
 
     fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
-        let result = Read::read_exact(&mut self.remaining_slice(), buf);
+        let result = Read::read_exact(&mut Cursor::split(self).1, buf);
 
         match result {
             Ok(_) => self.pos += buf.len() as u64,
@@ -365,14 +370,14 @@ where
     fn read_buf_exact(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
         let prev_written = cursor.written();
 
-        let result = Read::read_buf_exact(&mut self.remaining_slice(), cursor.reborrow());
+        let result = Read::read_buf_exact(&mut Cursor::split(self).1, cursor.reborrow());
         self.pos += (cursor.written() - prev_written) as u64;
 
         result
     }
 
     fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
-        let content = self.remaining_slice();
+        let content = Cursor::split(self).1;
         let len = content.len();
         buf.try_reserve(len)?;
         buf.extend_from_slice(content);
@@ -383,7 +388,7 @@ where
 
     fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
         let content =
-            crate::str::from_utf8(self.remaining_slice()).map_err(|_| io::Error::INVALID_UTF8)?;
+            crate::str::from_utf8(Cursor::split(self).1).map_err(|_| io::Error::INVALID_UTF8)?;
         let len = content.len();
         buf.try_reserve(len)?;
         buf.push_str(content);
@@ -399,7 +404,7 @@ where
     T: AsRef<[u8]>,
 {
     fn fill_buf(&mut self) -> io::Result<&[u8]> {
-        Ok(self.remaining_slice())
+        Ok(Cursor::split(self).1)
     }
     fn consume(&mut self, amt: usize) {
         self.pos += amt as u64;

library/std/src/io/tests.rs

@@ -676,13 +676,13 @@ fn cursor_read_exact_eof() {
 
     let mut r = slice.clone();
     assert!(r.read_exact(&mut [0; 10]).is_err());
-    assert!(r.is_empty());
+    assert!(Cursor::split(&r).1.is_empty());
 
     let mut r = slice;
     let buf = &mut [0; 10];
     let mut buf = BorrowedBuf::from(buf.as_mut_slice());
     assert!(r.read_buf_exact(buf.unfilled()).is_err());
-    assert!(r.is_empty());
+    assert!(Cursor::split(&r).1.is_empty());
     assert_eq!(buf.filled(), b"123456");
 }
 

library/std/src/sys/personality/dwarf/eh.rs

@@ -70,45 +70,51 @@ pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>) -> Result
 
     let func_start = context.func_start;
     let mut reader = DwarfReader::new(lsda);
-
-    let start_encoding = reader.read::<u8>();
-    // base address for landing pad offsets
-    let lpad_base = if start_encoding != DW_EH_PE_omit {
-        read_encoded_pointer(&mut reader, context, start_encoding)?
-    } else {
-        func_start
+    let lpad_base = unsafe {
+        let start_encoding = reader.read::<u8>();
+        // base address for landing pad offsets
+        if start_encoding != DW_EH_PE_omit {
+            read_encoded_pointer(&mut reader, context, start_encoding)?
+        } else {
+            func_start
+        }
     };
+    let call_site_encoding = unsafe {
+        let ttype_encoding = reader.read::<u8>();
+        if ttype_encoding != DW_EH_PE_omit {
+            // Rust doesn't analyze exception types, so we don't care about the type table
+            reader.read_uleb128();
+        }
 
-    let ttype_encoding = reader.read::<u8>();
-    if ttype_encoding != DW_EH_PE_omit {
-        // Rust doesn't analyze exception types, so we don't care about the type table
-        reader.read_uleb128();
-    }
-
-    let call_site_encoding = reader.read::<u8>();
-    let call_site_table_length = reader.read_uleb128();
-    let action_table = reader.ptr.add(call_site_table_length as usize);
+        reader.read::<u8>()
+    };
+    let action_table = unsafe {
+        let call_site_table_length = reader.read_uleb128();
+        reader.ptr.add(call_site_table_length as usize)
+    };
     let ip = context.ip;
 
     if !USING_SJLJ_EXCEPTIONS {
         // read the callsite table
         while reader.ptr < action_table {
-            // these are offsets rather than pointers;
-            let cs_start = read_encoded_offset(&mut reader, call_site_encoding)?;
-            let cs_len = read_encoded_offset(&mut reader, call_site_encoding)?;
-            let cs_lpad = read_encoded_offset(&mut reader, call_site_encoding)?;
-            let cs_action_entry = reader.read_uleb128();
-            // Callsite table is sorted by cs_start, so if we've passed the ip, we
-            // may stop searching.
-            if ip < func_start.wrapping_add(cs_start) {
-                break;
-            }
-            if ip < func_start.wrapping_add(cs_start + cs_len) {
-                if cs_lpad == 0 {
-                    return Ok(EHAction::None);
-                } else {
-                    let lpad = lpad_base.wrapping_add(cs_lpad);
-                    return Ok(interpret_cs_action(action_table, cs_action_entry, lpad));
+            unsafe {
+                // these are offsets rather than pointers;
+                let cs_start = read_encoded_offset(&mut reader, call_site_encoding)?;
+                let cs_len = read_encoded_offset(&mut reader, call_site_encoding)?;
+                let cs_lpad = read_encoded_offset(&mut reader, call_site_encoding)?;
+                let cs_action_entry = reader.read_uleb128();
+                // Callsite table is sorted by cs_start, so if we've passed the ip, we
+                // may stop searching.
+                if ip < func_start.wrapping_add(cs_start) {
+                    break;
+                }
+                if ip < func_start.wrapping_add(cs_start + cs_len) {
+                    if cs_lpad == 0 {
+                        return Ok(EHAction::None);
+                    } else {
+                        let lpad = lpad_base.wrapping_add(cs_lpad);
+                        return Ok(interpret_cs_action(action_table, cs_action_entry, lpad));
+                    }
                 }
             }
         }
@@ -125,15 +131,15 @@ pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>) -> Result
         }
         let mut idx = ip.addr();
         loop {
-            let cs_lpad = reader.read_uleb128();
-            let cs_action_entry = reader.read_uleb128();
+            let cs_lpad = unsafe { reader.read_uleb128() };
+            let cs_action_entry = unsafe { reader.read_uleb128() };
             idx -= 1;
             if idx == 0 {
                 // Can never have null landing pad for sjlj -- that would have
                 // been indicated by a -1 call site index.
                 // FIXME(strict provenance)
                 let lpad = ptr::with_exposed_provenance((cs_lpad + 1) as usize);
-                return Ok(interpret_cs_action(action_table, cs_action_entry, lpad));
+                return Ok(unsafe { interpret_cs_action(action_table, cs_action_entry, lpad) });
             }
         }
     }
@@ -151,9 +157,9 @@ unsafe fn interpret_cs_action(
     } else {
         // If lpad != 0 and cs_action_entry != 0, we have to check ttype_index.
         // If ttype_index == 0 under the condition, we take cleanup action.
-        let action_record = action_table.offset(cs_action_entry as isize - 1);
+        let action_record = unsafe { action_table.offset(cs_action_entry as isize - 1) };
         let mut action_reader = DwarfReader::new(action_record);
-        let ttype_index = action_reader.read_sleb128();
+        let ttype_index = unsafe { action_reader.read_sleb128() };
         if ttype_index == 0 {
             EHAction::Cleanup(lpad)
         } else if ttype_index > 0 {
@@ -186,18 +192,20 @@ unsafe fn read_encoded_offset(reader: &mut DwarfReader, encoding: u8) -> Result<
     if encoding == DW_EH_PE_omit || encoding & 0xF0 != 0 {
         return Err(());
     }
-    let result = match encoding & 0x0F {
-        // despite the name, LLVM also uses absptr for offsets instead of pointers
-        DW_EH_PE_absptr => reader.read::<usize>(),
-        DW_EH_PE_uleb128 => reader.read_uleb128() as usize,
-        DW_EH_PE_udata2 => reader.read::<u16>() as usize,
-        DW_EH_PE_udata4 => reader.read::<u32>() as usize,
-        DW_EH_PE_udata8 => reader.read::<u64>() as usize,
-        DW_EH_PE_sleb128 => reader.read_sleb128() as usize,
-        DW_EH_PE_sdata2 => reader.read::<i16>() as usize,
-        DW_EH_PE_sdata4 => reader.read::<i32>() as usize,
-        DW_EH_PE_sdata8 => reader.read::<i64>() as usize,
-        _ => return Err(()),
+    let result = unsafe {
+        match encoding & 0x0F {
+            // despite the name, LLVM also uses absptr for offsets instead of pointers
+            DW_EH_PE_absptr => reader.read::<usize>(),
+            DW_EH_PE_uleb128 => reader.read_uleb128() as usize,
+            DW_EH_PE_udata2 => reader.read::<u16>() as usize,
+            DW_EH_PE_udata4 => reader.read::<u32>() as usize,
+            DW_EH_PE_udata8 => reader.read::<u64>() as usize,
+            DW_EH_PE_sleb128 => reader.read_sleb128() as usize,
+            DW_EH_PE_sdata2 => reader.read::<i16>() as usize,
+            DW_EH_PE_sdata4 => reader.read::<i32>() as usize,
+            DW_EH_PE_sdata8 => reader.read::<i64>() as usize,
+            _ => return Err(()),
+        }
     };
     Ok(result)
 }
@@ -250,14 +258,14 @@ unsafe fn read_encoded_pointer(
         if encoding & 0x0F != DW_EH_PE_absptr {
             return Err(());
         }
-        reader.read::<*const u8>()
+        unsafe { reader.read::<*const u8>() }
     } else {
-        let offset = read_encoded_offset(reader, encoding & 0x0F)?;
+        let offset = unsafe { read_encoded_offset(reader, encoding & 0x0F)? };
         base_ptr.wrapping_add(offset)
     };
 
     if encoding & DW_EH_PE_indirect != 0 {
-        ptr = *(ptr.cast::<*const u8>());
+        ptr = unsafe { *(ptr.cast::<*const u8>()) };
     }
 
     Ok(ptr)

library/std/src/sys/personality/dwarf/mod.rs

@@ -5,6 +5,7 @@
 // This module is used only by x86_64-pc-windows-gnu for now, but we
 // are compiling it everywhere to avoid regressions.
 #![allow(unused)]
+#![forbid(unsafe_op_in_unsafe_fn)]
 
 #[cfg(test)]
 mod tests;
@@ -17,7 +18,6 @@ pub struct DwarfReader {
     pub ptr: *const u8,
 }
 
-#[forbid(unsafe_op_in_unsafe_fn)]
 impl DwarfReader {
     pub fn new(ptr: *const u8) -> DwarfReader {
         DwarfReader { ptr }

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

@@ -12,16 +12,6 @@ use crate::core::builder::{
 use crate::core::config::TargetSelection;
 use crate::{Compiler, Mode, Subcommand};
 
-pub fn cargo_subcommand(kind: Kind) -> &'static str {
-    match kind {
-        Kind::Check
-        // We ensure check steps for both std and rustc from build_steps/clippy, so handle `Kind::Clippy` as well.
-        | Kind::Clippy => "check",
-        Kind::Fix => "fix",
-        _ => unreachable!(),
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Std {
     pub target: TargetSelection,
@@ -31,11 +21,22 @@ pub struct Std {
     ///
     /// [`compile::Rustc`]: crate::core::build_steps::compile::Rustc
     crates: Vec<String>,
+    /// Override `Builder::kind` on cargo invocations.
+    ///
+    /// By default, `Builder::kind` is propagated as the subcommand to the cargo invocations.
+    /// However, there are cases when this is not desirable. For example, when running `x clippy $tool_name`,
+    /// passing `Builder::kind` to cargo invocations would run clippy on the entire compiler and library,
+    /// which is not useful if we only want to lint a few crates with specific rules.
+    override_build_kind: Option<Kind>,
 }
 
 impl Std {
     pub fn new(target: TargetSelection) -> Self {
-        Self { target, crates: vec![] }
+        Self::new_with_build_kind(target, None)
+    }
+
+    pub fn new_with_build_kind(target: TargetSelection, kind: Option<Kind>) -> Self {
+        Self { target, crates: vec![], override_build_kind: kind }
     }
 }
 
@@ -49,7 +50,7 @@ impl Step for Std {
 
     fn make_run(run: RunConfig<'_>) {
         let crates = run.make_run_crates(Alias::Library);
-        run.builder.ensure(Std { target: run.target, crates });
+        run.builder.ensure(Std { target: run.target, crates, override_build_kind: None });
     }
 
     fn run(self, builder: &Builder<'_>) {
@@ -64,7 +65,7 @@ impl Step for Std {
             Mode::Std,
             SourceType::InTree,
             target,
-            cargo_subcommand(builder.kind),
+            self.override_build_kind.unwrap_or(builder.kind),
         );
 
         std_cargo(builder, target, compiler.stage, &mut cargo);
@@ -118,7 +119,7 @@ impl Step for Std {
             Mode::Std,
             SourceType::InTree,
             target,
-            cargo_subcommand(builder.kind),
+            self.override_build_kind.unwrap_or(builder.kind),
         );
 
         // If we're not in stage 0, tests and examples will fail to compile
@@ -159,16 +160,31 @@ pub struct Rustc {
     ///
     /// [`compile::Rustc`]: crate::core::build_steps::compile::Rustc
     crates: Vec<String>,
+    /// Override `Builder::kind` on cargo invocations.
+    ///
+    /// By default, `Builder::kind` is propagated as the subcommand to the cargo invocations.
+    /// However, there are cases when this is not desirable. For example, when running `x clippy $tool_name`,
+    /// passing `Builder::kind` to cargo invocations would run clippy on the entire compiler and library,
+    /// which is not useful if we only want to lint a few crates with specific rules.
+    override_build_kind: Option<Kind>,
 }
 
 impl Rustc {
     pub fn new(target: TargetSelection, builder: &Builder<'_>) -> Self {
+        Self::new_with_build_kind(target, builder, None)
+    }
+
+    pub fn new_with_build_kind(
+        target: TargetSelection,
+        builder: &Builder<'_>,
+        kind: Option<Kind>,
+    ) -> Self {
         let crates = builder
             .in_tree_crates("rustc-main", Some(target))
             .into_iter()
             .map(|krate| krate.name.to_string())
             .collect();
-        Self { target, crates }
+        Self { target, crates, override_build_kind: kind }
     }
 }
 
@@ -183,7 +199,7 @@ impl Step for Rustc {
 
     fn make_run(run: RunConfig<'_>) {
         let crates = run.make_run_crates(Alias::Compiler);
-        run.builder.ensure(Rustc { target: run.target, crates });
+        run.builder.ensure(Rustc { target: run.target, crates, override_build_kind: None });
     }
 
     /// Builds the compiler.
@@ -204,7 +220,7 @@ impl Step for Rustc {
             builder.ensure(crate::core::build_steps::compile::Std::new(compiler, compiler.host));
             builder.ensure(crate::core::build_steps::compile::Std::new(compiler, target));
         } else {
-            builder.ensure(Std::new(target));
+            builder.ensure(Std::new_with_build_kind(target, self.override_build_kind));
         }
 
         let mut cargo = builder::Cargo::new(
@@ -213,7 +229,7 @@ impl Step for Rustc {
             Mode::Rustc,
             SourceType::InTree,
             target,
-            cargo_subcommand(builder.kind),
+            self.override_build_kind.unwrap_or(builder.kind),
         );
 
         rustc_cargo(builder, &mut cargo, target, &compiler);
@@ -291,7 +307,7 @@ impl Step for CodegenBackend {
             Mode::Codegen,
             SourceType::InTree,
             target,
-            cargo_subcommand(builder.kind),
+            builder.kind,
         );
 
         cargo
@@ -349,7 +365,7 @@ impl Step for RustAnalyzer {
             compiler,
             Mode::ToolRustc,
             target,
-            cargo_subcommand(builder.kind),
+            builder.kind,
             "src/tools/rust-analyzer",
             SourceType::InTree,
             &["in-rust-tree".to_owned()],
@@ -417,7 +433,7 @@ macro_rules! tool_check_step {
                     compiler,
                     Mode::ToolRustc,
                     target,
-                    cargo_subcommand(builder.kind),
+                    builder.kind,
                     $path,
                     $source_type,
                     &[],

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

@@ -11,7 +11,7 @@ use std::path::Path;
 
 use crate::core::builder::{crate_description, Builder, RunConfig, ShouldRun, Step};
 use crate::utils::helpers::t;
-use crate::{Build, Compiler, Mode, Subcommand};
+use crate::{Build, Compiler, Kind, Mode, Subcommand};
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct CleanAll {}
@@ -66,7 +66,7 @@ macro_rules! clean_crate_tree {
             fn run(self, builder: &Builder<'_>) -> Self::Output {
                 let compiler = self.compiler;
                 let target = compiler.host;
-                let mut cargo = builder.bare_cargo(compiler, $mode, target, "clean");
+                let mut cargo = builder.bare_cargo(compiler, $mode, target, Kind::Clean);
 
                 // Since https://github.com/rust-lang/rust/pull/111076 enables
                 // unstable cargo feature (`public-dependency`), we need to ensure

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

@@ -116,8 +116,14 @@ impl Step for Std {
         let target = self.target;
         let compiler = builder.compiler(builder.top_stage, builder.config.build);
 
-        let mut cargo =
-            builder::Cargo::new(builder, compiler, Mode::Std, SourceType::InTree, target, "clippy");
+        let mut cargo = builder::Cargo::new(
+            builder,
+            compiler,
+            Mode::Std,
+            SourceType::InTree,
+            target,
+            Kind::Clippy,
+        );
 
         std_cargo(builder, target, compiler.stage, &mut cargo);
 
@@ -178,7 +184,7 @@ impl Step for Rustc {
             builder.ensure(compile::Std::new(compiler, compiler.host));
             builder.ensure(compile::Std::new(compiler, target));
         } else {
-            builder.ensure(check::Std::new(target));
+            builder.ensure(check::Std::new_with_build_kind(target, Some(Kind::Check)));
         }
 
         let mut cargo = builder::Cargo::new(
@@ -187,7 +193,7 @@ impl Step for Rustc {
             Mode::Rustc,
             SourceType::InTree,
             target,
-            "clippy",
+            Kind::Clippy,
         );
 
         rustc_cargo(builder, &mut cargo, target, &compiler);
@@ -245,14 +251,14 @@ macro_rules! lint_any {
                 let compiler = builder.compiler(builder.top_stage, builder.config.build);
                 let target = self.target;
 
-                builder.ensure(check::Rustc::new(target, builder));
+                builder.ensure(check::Rustc::new_with_build_kind(target, builder, Some(Kind::Check)));
 
                 let cargo = prepare_tool_cargo(
                     builder,
                     compiler,
                     Mode::ToolRustc,
                     target,
-                    "clippy",
+                    Kind::Clippy,
                     $path,
                     SourceType::InTree,
                     &[],

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

@@ -247,7 +247,7 @@ impl Step for Std {
                 Mode::Std,
                 SourceType::InTree,
                 target,
-                "check",
+                Kind::Check,
             );
             cargo.rustflag("-Zalways-encode-mir");
             cargo.arg("--manifest-path").arg(builder.src.join("library/sysroot/Cargo.toml"));
@@ -259,7 +259,7 @@ impl Step for Std {
                 Mode::Std,
                 SourceType::InTree,
                 target,
-                "build",
+                Kind::Build,
             );
             std_cargo(builder, target, compiler.stage, &mut cargo);
             for krate in &*self.crates {
@@ -919,7 +919,7 @@ impl Step for Rustc {
             Mode::Rustc,
             SourceType::InTree,
             target,
-            "build",
+            Kind::Build,
         );
 
         rustc_cargo(builder, &mut cargo, target, &compiler);
@@ -1359,7 +1359,7 @@ impl Step for CodegenBackend {
             Mode::Codegen,
             SourceType::InTree,
             target,
-            "build",
+            Kind::Build,
         );
         cargo
             .arg("--manifest-path")

src/bootstrap/src/core/build_steps/doc.rs

@@ -714,7 +714,7 @@ fn doc_std(
     let out_dir = target_dir.join(target.triple).join("doc");
 
     let mut cargo =
-        builder::Cargo::new(builder, compiler, Mode::Std, SourceType::InTree, target, "doc");
+        builder::Cargo::new(builder, compiler, Mode::Std, SourceType::InTree, target, Kind::Doc);
 
     compile::std_cargo(builder, target, compiler.stage, &mut cargo);
     cargo
@@ -816,8 +816,14 @@ impl Step for Rustc {
         );
 
         // Build cargo command.
-        let mut cargo =
-            builder::Cargo::new(builder, compiler, Mode::Rustc, SourceType::InTree, target, "doc");
+        let mut cargo = builder::Cargo::new(
+            builder,
+            compiler,
+            Mode::Rustc,
+            SourceType::InTree,
+            target,
+            Kind::Doc,
+        );
 
         cargo.rustdocflag("--document-private-items");
         // Since we always pass --document-private-items, there's no need to warn about linking to private items.
@@ -964,7 +970,7 @@ macro_rules! tool_doc {
                     compiler,
                     Mode::ToolRustc,
                     target,
-                    "doc",
+                    Kind::Doc,
                     $path,
                     source_type,
                     &[],

src/bootstrap/src/core/build_steps/run.rs

@@ -8,7 +8,7 @@ use std::path::PathBuf;
 use crate::core::build_steps::dist::distdir;
 use crate::core::build_steps::test;
 use crate::core::build_steps::tool::{self, SourceType, Tool};
-use crate::core::builder::{Builder, RunConfig, ShouldRun, Step};
+use crate::core::builder::{Builder, Kind, RunConfig, ShouldRun, Step};
 use crate::core::config::flags::get_completion;
 use crate::core::config::TargetSelection;
 use crate::utils::exec::command;
@@ -142,7 +142,7 @@ impl Step for Miri {
             host_compiler,
             Mode::ToolRustc,
             host,
-            "run",
+            Kind::Run,
             "src/tools/miri",
             SourceType::InTree,
             &[],

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

@@ -68,7 +68,7 @@ impl Step for CrateBootstrap {
             compiler,
             Mode::ToolBootstrap,
             bootstrap_host,
-            "test",
+            Kind::Test,
             path,
             SourceType::InTree,
             &[],
@@ -119,7 +119,7 @@ You can skip linkcheck with --skip src/tools/linkchecker"
             compiler,
             Mode::ToolBootstrap,
             bootstrap_host,
-            "test",
+            Kind::Test,
             "src/tools/linkchecker",
             SourceType::InTree,
             &[],
@@ -284,7 +284,7 @@ impl Step for Cargo {
             compiler,
             Mode::ToolRustc,
             self.host,
-            "test",
+            Kind::Test,
             "src/tools/cargo",
             SourceType::Submodule,
             &[],
@@ -355,7 +355,7 @@ impl Step for RustAnalyzer {
             compiler,
             Mode::ToolRustc,
             host,
-            "test",
+            Kind::Test,
             crate_path,
             SourceType::InTree,
             &["in-rust-tree".to_owned()],
@@ -407,7 +407,7 @@ impl Step for Rustfmt {
             compiler,
             Mode::ToolRustc,
             host,
-            "test",
+            Kind::Test,
             "src/tools/rustfmt",
             SourceType::InTree,
             &[],
@@ -442,7 +442,7 @@ impl Miri {
             Mode::Std,
             SourceType::Submodule,
             target,
-            "miri-setup",
+            Kind::MiriSetup,
         );
 
         // Tell `cargo miri setup` where to find the sources.
@@ -527,7 +527,7 @@ impl Step for Miri {
             host_compiler,
             Mode::ToolRustc,
             host,
-            "test",
+            Kind::Test,
             "src/tools/miri",
             SourceType::InTree,
             &[],
@@ -617,7 +617,7 @@ impl Step for CargoMiri {
             compiler,
             Mode::ToolStd, // it's unclear what to use here, we're not building anything just doing a smoke test!
             target,
-            "miri-test",
+            Kind::MiriTest,
             "src/tools/miri/test-cargo-miri",
             SourceType::Submodule,
             &[],
@@ -677,7 +677,7 @@ impl Step for CompiletestTest {
             // when std sources change.
             Mode::ToolStd,
             host,
-            "test",
+            Kind::Test,
             "src/tools/compiletest",
             SourceType::InTree,
             &[],
@@ -727,7 +727,7 @@ impl Step for Clippy {
             compiler,
             Mode::ToolRustc,
             host,
-            "test",
+            Kind::Test,
             "src/tools/clippy",
             SourceType::InTree,
             &[],
@@ -1277,7 +1277,7 @@ impl Step for RunMakeSupport {
             self.compiler,
             Mode::ToolStd,
             self.target,
-            "build",
+            Kind::Build,
             "src/tools/run-make-support",
             SourceType::InTree,
             &[],
@@ -1321,7 +1321,7 @@ impl Step for CrateRunMakeSupport {
             compiler,
             Mode::ToolBootstrap,
             host,
-            "test",
+            Kind::Test,
             "src/tools/run-make-support",
             SourceType::InTree,
             &[],
@@ -1367,7 +1367,7 @@ impl Step for CrateBuildHelper {
             compiler,
             Mode::ToolBootstrap,
             host,
-            "test",
+            Kind::Test,
             "src/tools/build_helper",
             SourceType::InTree,
             &[],
@@ -2631,7 +2631,7 @@ impl Step for Crate {
                 mode,
                 SourceType::InTree,
                 target,
-                "miri-test",
+                Kind::MiriTest,
             );
             // This hack helps bootstrap run standard library tests in Miri. The issue is as
             // follows: when running `cargo miri test` on libcore, cargo builds a local copy of core
@@ -2654,14 +2654,7 @@ impl Step for Crate {
             }
 
             // Build `cargo test` command
-            builder::Cargo::new(
-                builder,
-                compiler,
-                mode,
-                SourceType::InTree,
-                target,
-                builder.kind.as_str(),
-            )
+            builder::Cargo::new(builder, compiler, mode, SourceType::InTree, target, builder.kind)
         };
 
         match mode {
@@ -2753,7 +2746,7 @@ impl Step for CrateRustdoc {
             compiler,
             Mode::ToolRustc,
             target,
-            builder.kind.as_str(),
+            builder.kind,
             "src/tools/rustdoc",
             SourceType::InTree,
             &[],
@@ -2845,7 +2838,7 @@ impl Step for CrateRustdocJsonTypes {
             compiler,
             Mode::ToolRustc,
             target,
-            builder.kind.as_str(),
+            builder.kind,
             "src/rustdoc-json-types",
             SourceType::InTree,
             &[],
@@ -3079,7 +3072,7 @@ impl Step for TierCheck {
             self.compiler,
             Mode::ToolStd,
             self.compiler.host,
-            "run",
+            Kind::Run,
             "src/tools/tier-check",
             SourceType::InTree,
             &[],
@@ -3151,7 +3144,7 @@ impl Step for RustInstaller {
             compiler,
             Mode::ToolBootstrap,
             bootstrap_host,
-            "test",
+            Kind::Test,
             "src/tools/rust-installer",
             SourceType::InTree,
             &[],
@@ -3321,7 +3314,7 @@ impl Step for CodegenCranelift {
                 Mode::Codegen, // Must be codegen to ensure dlopen on compiled dylibs works
                 SourceType::InTree,
                 target,
-                "run",
+                Kind::Run,
             );
 
             cargo.current_dir(&builder.src.join("compiler/rustc_codegen_cranelift"));
@@ -3453,7 +3446,7 @@ impl Step for CodegenGCC {
                 Mode::Codegen, // Must be codegen to ensure dlopen on compiled dylibs works
                 SourceType::InTree,
                 target,
-                "run",
+                Kind::Run,
             );
 
             cargo.current_dir(&builder.src.join("compiler/rustc_codegen_gcc"));
@@ -3541,7 +3534,7 @@ impl Step for TestFloatParse {
             compiler,
             Mode::ToolStd,
             bootstrap_host,
-            "test",
+            Kind::Test,
             path,
             SourceType::InTree,
             &[],
@@ -3564,7 +3557,7 @@ impl Step for TestFloatParse {
             compiler,
             Mode::ToolStd,
             bootstrap_host,
-            "run",
+            Kind::Run,
             path,
             SourceType::InTree,
             &[],

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

@@ -90,7 +90,7 @@ impl Step for ToolBuild {
             compiler,
             self.mode,
             target,
-            "build",
+            Kind::Build,
             path,
             self.source_type,
             &self.extra_features,
@@ -136,12 +136,12 @@ pub fn prepare_tool_cargo(
     compiler: Compiler,
     mode: Mode,
     target: TargetSelection,
-    command: &'static str,
+    cmd_kind: Kind,
     path: &str,
     source_type: SourceType,
     extra_features: &[String],
 ) -> CargoCommand {
-    let mut cargo = builder::Cargo::new(builder, compiler, mode, source_type, target, command);
+    let mut cargo = builder::Cargo::new(builder, compiler, mode, source_type, target, cmd_kind);
 
     let dir = builder.src.join(path);
     cargo.arg("--manifest-path").arg(dir.join("Cargo.toml"));
@@ -646,7 +646,7 @@ impl Step for Rustdoc {
             build_compiler,
             Mode::ToolRustc,
             target,
-            "build",
+            Kind::Build,
             "src/tools/rustdoc",
             SourceType::InTree,
             features.as_slice(),
@@ -905,7 +905,7 @@ impl Step for LlvmBitcodeLinker {
             self.compiler,
             Mode::ToolRustc,
             self.target,
-            "build",
+            Kind::Build,
             "src/tools/llvm-bitcode-linker",
             SourceType::InTree,
             &self.extra_features,

src/bootstrap/src/core/builder.rs

@@ -689,7 +689,7 @@ impl<'a> ShouldRun<'a> {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum)]
+#[derive(Debug, Copy, Clone, Eq, Hash, PartialEq, PartialOrd, Ord, ValueEnum)]
 pub enum Kind {
     #[value(alias = "b")]
     Build,
@@ -701,6 +701,8 @@ pub enum Kind {
     #[value(alias = "t")]
     Test,
     Miri,
+    MiriSetup,
+    MiriTest,
     Bench,
     #[value(alias = "d")]
     Doc,
@@ -725,6 +727,8 @@ impl Kind {
             Kind::Format => "fmt",
             Kind::Test => "test",
             Kind::Miri => "miri",
+            Kind::MiriSetup => panic!("`as_str` is not supported for `Kind::MiriSetup`."),
+            Kind::MiriTest => panic!("`as_str` is not supported for `Kind::MiriTest`."),
             Kind::Bench => "bench",
             Kind::Doc => "doc",
             Kind::Clean => "clean",
@@ -1000,6 +1004,7 @@ impl<'a> Builder<'a> {
             Kind::Vendor => describe!(vendor::Vendor),
             // special-cased in Build::build()
             Kind::Format | Kind::Suggest | Kind::Perf => vec![],
+            Kind::MiriTest | Kind::MiriSetup => unreachable!(),
         }
     }
 
@@ -1386,23 +1391,30 @@ impl<'a> Builder<'a> {
         compiler: Compiler,
         mode: Mode,
         target: TargetSelection,
-        cmd: &str, // FIXME make this properly typed
+        cmd_kind: Kind,
     ) -> BootstrapCommand {
-        let mut cargo;
-        if cmd == "clippy" {
-            cargo = self.cargo_clippy_cmd(compiler);
-            cargo.arg(cmd);
-        } else if let Some(subcmd) = cmd.strip_prefix("miri") {
-            // Command must be "miri-X".
-            let subcmd = subcmd
-                .strip_prefix('-')
-                .unwrap_or_else(|| panic!("expected `miri-$subcommand`, but got {}", cmd));
-            cargo = self.cargo_miri_cmd(compiler);
-            cargo.arg("miri").arg(subcmd);
-        } else {
-            cargo = command(&self.initial_cargo);
-            cargo.arg(cmd);
-        }
+        let mut cargo = match cmd_kind {
+            Kind::Clippy => {
+                let mut cargo = self.cargo_clippy_cmd(compiler);
+                cargo.arg(cmd_kind.as_str());
+                cargo
+            }
+            Kind::MiriSetup => {
+                let mut cargo = self.cargo_miri_cmd(compiler);
+                cargo.arg("miri").arg("setup");
+                cargo
+            }
+            Kind::MiriTest => {
+                let mut cargo = self.cargo_miri_cmd(compiler);
+                cargo.arg("miri").arg("test");
+                cargo
+            }
+            _ => {
+                let mut cargo = command(&self.initial_cargo);
+                cargo.arg(cmd_kind.as_str());
+                cargo
+            }
+        };
 
         // Run cargo from the source root so it can find .cargo/config.
         // This matters when using vendoring and the working directory is outside the repository.
@@ -1431,7 +1443,7 @@ impl<'a> Builder<'a> {
             Color::Auto => {} // nothing to do
         }
 
-        if cmd != "install" {
+        if cmd_kind != Kind::Install {
             cargo.arg("--target").arg(target.rustc_target_arg());
         } else {
             assert_eq!(target, compiler.host);
@@ -1440,8 +1452,11 @@ impl<'a> Builder<'a> {
         if self.config.rust_optimize.is_release() {
             // FIXME: cargo bench/install do not accept `--release`
             // and miri doesn't want it
-            if cmd != "bench" && cmd != "install" && !cmd.starts_with("miri-") {
-                cargo.arg("--release");
+            match cmd_kind {
+                Kind::Bench | Kind::Install | Kind::Miri | Kind::MiriSetup | Kind::MiriTest => {}
+                _ => {
+                    cargo.arg("--release");
+                }
             }
         }
 
@@ -1464,9 +1479,9 @@ impl<'a> Builder<'a> {
         mode: Mode,
         source_type: SourceType,
         target: TargetSelection,
-        cmd: &str, // FIXME make this properly typed
+        cmd_kind: Kind,
     ) -> Cargo {
-        let mut cargo = self.bare_cargo(compiler, mode, target, cmd);
+        let mut cargo = self.bare_cargo(compiler, mode, target, cmd_kind);
         let out_dir = self.stage_out(compiler, mode);
 
         let mut hostflags = HostFlags::default();
@@ -1477,7 +1492,7 @@ impl<'a> Builder<'a> {
             self.clear_if_dirty(&out_dir, &backend);
         }
 
-        if cmd == "doc" || cmd == "rustdoc" {
+        if cmd_kind == Kind::Doc {
             let my_out = match mode {
                 // This is the intended out directory for compiler documentation.
                 Mode::Rustc | Mode::ToolRustc => self.compiler_doc_out(target),
@@ -1508,7 +1523,7 @@ impl<'a> Builder<'a> {
 
         // Set a flag for `check`/`clippy`/`fix`, so that certain build
         // scripts can do less work (i.e. not building/requiring LLVM).
-        if cmd == "check" || cmd == "clippy" || cmd == "fix" {
+        if matches!(cmd_kind, Kind::Check | Kind::Clippy | Kind::Fix) {
             // If we've not yet built LLVM, or it's stale, then bust
             // the rustc_llvm cache. That will always work, even though it
             // may mean that on the next non-check build we'll need to rebuild
@@ -1558,7 +1573,7 @@ impl<'a> Builder<'a> {
             rustflags.arg("--cfg=bootstrap");
         }
 
-        if cmd == "clippy" {
+        if cmd_kind == Kind::Clippy {
             // clippy overwrites sysroot if we pass it to cargo.
             // Pass it directly to clippy instead.
             // NOTE: this can't be fixed in clippy because we explicitly don't set `RUSTC`,
@@ -1654,7 +1669,7 @@ impl<'a> Builder<'a> {
             Mode::Std | Mode::ToolBootstrap | Mode::ToolStd => {}
             Mode::Rustc | Mode::Codegen | Mode::ToolRustc => {
                 // Build proc macros both for the host and the target
-                if target != compiler.host && cmd != "check" {
+                if target != compiler.host && cmd_kind != Kind::Check {
                     cargo.arg("-Zdual-proc-macros");
                     rustflags.arg("-Zdual-proc-macros");
                 }
@@ -1739,7 +1754,7 @@ impl<'a> Builder<'a> {
         }
         cargo.env("__CARGO_DEFAULT_LIB_METADATA", &metadata);
 
-        if cmd == "clippy" {
+        if cmd_kind == Kind::Clippy {
             rustflags.arg("-Zforce-unstable-if-unmarked");
         }
 
@@ -1755,10 +1770,15 @@ impl<'a> Builder<'a> {
         //
         // Only clear out the directory if we're compiling std; otherwise, we
         // should let Cargo take care of things for us (via depdep info)
-        if !self.config.dry_run() && mode == Mode::Std && cmd == "build" {
+        if !self.config.dry_run() && mode == Mode::Std && cmd_kind == Kind::Build {
             self.clear_if_dirty(&out_dir, &self.rustc(compiler));
         }
 
+        let rustdoc_path = match cmd_kind {
+            Kind::Doc | Kind::Test | Kind::MiriTest => self.rustdoc(compiler),
+            _ => PathBuf::from("/path/to/nowhere/rustdoc/not/required"),
+        };
+
         // Customize the compiler we're running. Specify the compiler to cargo
         // as our shim and then pass it some various options used to configure
         // how the actual compiler itself is called.
@@ -1772,15 +1792,7 @@ impl<'a> Builder<'a> {
             .env("RUSTC_SYSROOT", sysroot)
             .env("RUSTC_LIBDIR", libdir)
             .env("RUSTDOC", self.bootstrap_out.join("rustdoc"))
-            .env(
-                "RUSTDOC_REAL",
-                // Make sure to handle both `test` and `miri-test` commands.
-                if cmd == "doc" || cmd == "rustdoc" || (cmd.ends_with("test") && want_rustdoc) {
-                    self.rustdoc(compiler)
-                } else {
-                    PathBuf::from("/path/to/nowhere/rustdoc/not/required")
-                },
-            )
+            .env("RUSTDOC_REAL", rustdoc_path)
             .env("RUSTC_ERROR_METADATA_DST", self.extended_error_dir())
             .env("RUSTC_BREAK_ON_ICE", "1");
 
@@ -1799,7 +1811,7 @@ impl<'a> Builder<'a> {
         }
 
         // If this is for `miri-test`, prepare the sysroots.
-        if cmd == "miri-test" {
+        if cmd_kind == Kind::MiriTest {
             self.ensure(compile::Std::new(compiler, compiler.host));
             let host_sysroot = self.sysroot(compiler);
             let miri_sysroot = test::Miri::build_miri_sysroot(self, compiler, target);
@@ -1813,7 +1825,8 @@ impl<'a> Builder<'a> {
             rustflags.arg(&format!("-Zstack-protector={stack_protector}"));
         }
 
-        if !(["build", "check", "clippy", "fix", "rustc"].contains(&cmd)) && want_rustdoc {
+        if !matches!(cmd_kind, Kind::Build | Kind::Check | Kind::Clippy | Kind::Fix) && want_rustdoc
+        {
             cargo.env("RUSTDOC_LIBDIR", self.rustc_libdir(compiler));
         }
 
@@ -2430,9 +2443,9 @@ impl Cargo {
         mode: Mode,
         source_type: SourceType,
         target: TargetSelection,
-        cmd: &str, // FIXME make this properly typed
+        cmd_kind: Kind,
     ) -> Cargo {
-        let mut cargo = builder.cargo(compiler, mode, source_type, target, cmd);
+        let mut cargo = builder.cargo(compiler, mode, source_type, target, cmd_kind);
         cargo.configure_linker(builder);
         cargo
     }
@@ -2448,9 +2461,9 @@ impl Cargo {
         mode: Mode,
         source_type: SourceType,
         target: TargetSelection,
-        cmd: &str, // FIXME make this properly typed
+        cmd_kind: Kind,
     ) -> Cargo {
-        builder.cargo(compiler, mode, source_type, target, cmd)
+        builder.cargo(compiler, mode, source_type, target, cmd_kind)
     }
 
     pub fn rustdocflag(&mut self, arg: &str) -> &mut Cargo {