Auto merge of #144773 - RalfJung:rollup-uif2yyj, r=RalfJung

Rollup of 6 pull requests Successful merges: - rust-lang/rust#144397 (`tests/ui/issues/`: The Issues Strike Back [2/N]) - rust-lang/rust#144410 (Make tier 3 musl targets link dynamically by default) - rust-lang/rust#144708 (Add tracing to step.rs and friends) - rust-lang/rust#144730 (Create a typed wrapper for codegen backends in bootstrap) - rust-lang/rust#144771 (Remove some noisy triagebot pings for myself) - rust-lang/rust#144772 (add unsupported_calling_conventions to lint list) r? `@ghost` `@rustbot` modify labels: rollup
2026-04-27 18:57:42 +03:00 · 2025-08-01 10:20:07 +00:00
parent e3ee7f7aea 21140a5111
commit 924a5a4b7f
76 changed files with 359 additions and 173 deletions
@@ -11,6 +11,7 @@
 use rustc_middle::{bug, mir, span_bug};
 use rustc_span::sym;
 use rustc_target::callconv::{ArgAbi, FnAbi, PassMode};
+use tracing::field::Empty;
 use tracing::{info, instrument, trace};

 use super::{
@@ -18,7 +19,8 @@
    Projectable, Provenance, ReturnAction, ReturnContinuation, Scalar, StackPopInfo, interp_ok,
    throw_ub, throw_ub_custom, throw_unsup_format,
 };
-use crate::fluent_generated as fluent;
+use crate::interpret::EnteredTraceSpan;
+use crate::{enter_trace_span, fluent_generated as fluent};

 /// An argument passed to a function.
 #[derive(Clone, Debug)]
@@ -344,6 +346,8 @@ pub fn init_stack_frame(
        destination: &PlaceTy<'tcx, M::Provenance>,
        mut cont: ReturnContinuation,
    ) -> InterpResult<'tcx> {
+        let _span = enter_trace_span!(M, step::init_stack_frame, %instance, tracing_separate_thread = Empty);
+
        // Compute callee information.
        // FIXME: for variadic support, do we have to somehow determine callee's extra_args?
        let callee_fn_abi = self.fn_abi_of_instance(instance, ty::List::empty())?;
@@ -523,7 +527,9 @@ pub(super) fn init_fn_call(
        target: Option<mir::BasicBlock>,
        unwind: mir::UnwindAction,
    ) -> InterpResult<'tcx> {
-        trace!("init_fn_call: {:#?}", fn_val);
+        let _span =
+            enter_trace_span!(M, step::init_fn_call, tracing_separate_thread = Empty, ?fn_val)
+                .or_if_tracing_disabled(|| trace!("init_fn_call: {:#?}", fn_val));

        let instance = match fn_val {
            FnVal::Instance(instance) => instance,
@@ -13,6 +13,7 @@
 use rustc_middle::ty::{ConstInt, ScalarInt, Ty, TyCtxt};
 use rustc_middle::{bug, mir, span_bug, ty};
 use rustc_span::DUMMY_SP;
+use tracing::field::Empty;
 use tracing::trace;

 use super::{
@@ -20,6 +21,7 @@
    OffsetMode, PlaceTy, Pointer, Projectable, Provenance, Scalar, alloc_range, err_ub,
    from_known_layout, interp_ok, mir_assign_valid_types, throw_ub,
 };
+use crate::enter_trace_span;

 /// An `Immediate` represents a single immediate self-contained Rust value.
 ///
@@ -770,6 +772,13 @@ pub fn eval_place_to_op(
        mir_place: mir::Place<'tcx>,
        layout: Option<TyAndLayout<'tcx>>,
    ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
+        let _span = enter_trace_span!(
+            M,
+            step::eval_place_to_op,
+            ?mir_place,
+            tracing_separate_thread = Empty
+        );
+
        // Do not use the layout passed in as argument if the base we are looking at
        // here is not the entire place.
        let layout = if mir_place.projection.is_empty() { layout } else { None };
@@ -813,6 +822,9 @@ pub fn eval_operand(
        mir_op: &mir::Operand<'tcx>,
        layout: Option<TyAndLayout<'tcx>>,
    ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
+        let _span =
+            enter_trace_span!(M, step::eval_operand, ?mir_op, tracing_separate_thread = Empty);
+
        use rustc_middle::mir::Operand::*;
        let op = match mir_op {
            // FIXME: do some more logic on `move` to invalidate the old location
@@ -9,6 +9,7 @@
 use rustc_middle::ty::Ty;
 use rustc_middle::ty::layout::TyAndLayout;
 use rustc_middle::{bug, mir, span_bug};
+use tracing::field::Empty;
 use tracing::{instrument, trace};

 use super::{
@@ -16,6 +17,7 @@
    InterpResult, Machine, MemoryKind, Misalignment, OffsetMode, OpTy, Operand, Pointer,
    Projectable, Provenance, Scalar, alloc_range, interp_ok, mir_assign_valid_types,
 };
+use crate::enter_trace_span;

 #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
 /// Information required for the sound usage of a `MemPlace`.
@@ -524,6 +526,9 @@ pub fn eval_place(
        &self,
        mir_place: mir::Place<'tcx>,
    ) -> InterpResult<'tcx, PlaceTy<'tcx, M::Provenance>> {
+        let _span =
+            enter_trace_span!(M, step::eval_place, ?mir_place, tracing_separate_thread = Empty);
+
        let mut place = self.local_to_place(mir_place.local)?;
        // Using `try_fold` turned out to be bad for performance, hence the loop.
        for elem in mir_place.projection.iter() {
@@ -9,13 +9,15 @@
 use rustc_middle::{bug, mir, span_bug};
 use rustc_span::source_map::Spanned;
 use rustc_target::callconv::FnAbi;
+use tracing::field::Empty;
 use tracing::{info, instrument, trace};

 use super::{
    FnArg, FnVal, ImmTy, Immediate, InterpCx, InterpResult, Machine, MemPlaceMeta, PlaceTy,
    Projectable, Scalar, interp_ok, throw_ub, throw_unsup_format,
 };
-use crate::util;
+use crate::interpret::EnteredTraceSpan;
+use crate::{enter_trace_span, util};

 struct EvaluatedCalleeAndArgs<'tcx, M: Machine<'tcx>> {
    callee: FnVal<'tcx, M::ExtraFnVal>,
@@ -74,7 +76,14 @@ pub fn step(&mut self) -> InterpResult<'tcx, bool> {
    ///
    /// This does NOT move the statement counter forward, the caller has to do that!
    pub fn eval_statement(&mut self, stmt: &mir::Statement<'tcx>) -> InterpResult<'tcx> {
-        info!("{:?}", stmt);
+        let _span = enter_trace_span!(
+            M,
+            step::eval_statement,
+            stmt = ?stmt.kind,
+            span = ?stmt.source_info.span,
+            tracing_separate_thread = Empty,
+        )
+        .or_if_tracing_disabled(|| info!(stmt = ?stmt.kind));

        use rustc_middle::mir::StatementKind::*;

@@ -456,7 +465,14 @@ fn eval_callee_and_args(
    }

    fn eval_terminator(&mut self, terminator: &mir::Terminator<'tcx>) -> InterpResult<'tcx> {
-        info!("{:?}", terminator.kind);
+        let _span = enter_trace_span!(
+            M,
+            step::eval_terminator,
+            terminator = ?terminator.kind,
+            span = ?terminator.source_info.span,
+            tracing_separate_thread = Empty,
+        )
+        .or_if_tracing_disabled(|| info!(terminator = ?terminator.kind));

        use rustc_middle::mir::TerminatorKind::*;
        match terminator.kind {
@@ -48,10 +48,24 @@ pub(crate) fn create_static_alloc<'tcx>(

 /// A marker trait returned by [crate::interpret::Machine::enter_trace_span], identifying either a
 /// real [tracing::span::EnteredSpan] in case tracing is enabled, or the dummy type `()` when
-/// tracing is disabled.
-pub trait EnteredTraceSpan {}
-impl EnteredTraceSpan for () {}
-impl EnteredTraceSpan for tracing::span::EnteredSpan {}
+/// tracing is disabled. Also see [crate::enter_trace_span!] below.
+pub trait EnteredTraceSpan {
+    /// Allows executing an alternative function when tracing is disabled. Useful for example if you
+    /// want to open a trace span when tracing is enabled, and alternatively just log a line when
+    /// tracing is disabled.
+    fn or_if_tracing_disabled(self, f: impl FnOnce()) -> Self;
+}
+impl EnteredTraceSpan for () {
+    fn or_if_tracing_disabled(self, f: impl FnOnce()) -> Self {
+        f(); // tracing is disabled, execute the function
+        self
+    }
+}
+impl EnteredTraceSpan for tracing::span::EnteredSpan {
+    fn or_if_tracing_disabled(self, _f: impl FnOnce()) -> Self {
+        self // tracing is enabled, don't execute anything
+    }
+}

 /// Shortand for calling [crate::interpret::Machine::enter_trace_span] on a [tracing::info_span!].
 /// This is supposed to be compiled out when [crate::interpret::Machine::enter_trace_span] has the
@@ -112,6 +126,19 @@ impl EnteredTraceSpan for tracing::span::EnteredSpan {}
 /// # type M = rustc_const_eval::const_eval::CompileTimeMachine<'static>;
 /// let _span = enter_trace_span!(M, step::eval_statement, tracing_separate_thread = tracing::field::Empty);
 /// ```
+///
+/// ### Executing something else when tracing is disabled
+///
+/// [crate::interpret::Machine::enter_trace_span] returns [EnteredTraceSpan], on which you can call
+/// [EnteredTraceSpan::or_if_tracing_disabled], to e.g. log a line as an alternative to the tracing
+/// span for when tracing is disabled. For example:
+/// ```rust
+/// # use rustc_const_eval::enter_trace_span;
+/// # use rustc_const_eval::interpret::EnteredTraceSpan;
+/// # type M = rustc_const_eval::const_eval::CompileTimeMachine<'static>;
+/// let _span = enter_trace_span!(M, step::eval_statement)
+///     .or_if_tracing_disabled(|| tracing::info!("eval_statement"));
+/// ```
 #[macro_export]
 macro_rules! enter_trace_span {
    ($machine:ty, $name:ident :: $subname:ident $($tt:tt)*) => {
@@ -125,6 +125,7 @@
        UNSAFE_OP_IN_UNSAFE_FN,
        UNSTABLE_NAME_COLLISIONS,
        UNSTABLE_SYNTAX_PRE_EXPANSION,
+        UNSUPPORTED_CALLING_CONVENTIONS,
        UNUSED_ASSIGNMENTS,
        UNUSED_ASSOCIATED_TYPE_BOUNDS,
        UNUSED_ATTRIBUTES,
@@ -7,7 +7,6 @@ pub(crate) fn target() -> Target {
    // FIXME: HVX length defaults are per-CPU
    base.features = "-small-data,+hvx-length128b".into();

-    base.crt_static_default = false;
    base.has_rpath = true;
    base.linker_flavor = LinkerFlavor::Unix(Cc::Yes);

@@ -23,8 +23,6 @@ pub(crate) fn target() -> Target {
            abi: "abi64".into(),
            endian: Endian::Big,
            mcount: "_mcount".into(),
-            // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-            crt_static_default: true,
            llvm_abiname: "n64".into(),
            ..base
        },
@@ -10,8 +10,6 @@ pub(crate) fn target() -> Target {
    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m64"]);
    base.max_atomic_width = Some(64);
    base.stack_probes = StackProbeType::Inline;
-    // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-    base.crt_static_default = true;
    base.abi = "elfv2".into();
    base.llvm_abiname = "elfv2".into();

@@ -9,8 +9,6 @@ pub(crate) fn target() -> Target {
    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);
    base.max_atomic_width = Some(32);
    base.stack_probes = StackProbeType::Inline;
-    // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-    base.crt_static_default = true;

    Target {
        llvm_target: "powerpc-unknown-linux-musl".into(),
@@ -9,8 +9,6 @@ pub(crate) fn target() -> Target {
    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-mspe"]);
    base.max_atomic_width = Some(32);
    base.stack_probes = StackProbeType::Inline;
-    // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-    base.crt_static_default = true;

    Target {
        llvm_target: "powerpc-unknown-linux-muslspe".into(),
@@ -23,8 +23,6 @@ pub(crate) fn target() -> Target {
            llvm_abiname: "ilp32d".into(),
            max_atomic_width: Some(32),
            supported_split_debuginfo: Cow::Borrowed(&[SplitDebuginfo::Off]),
-            // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-            crt_static_default: true,
            ..base::linux_musl::opts()
        },
    }
@@ -13,8 +13,6 @@ pub(crate) fn target() -> Target {
    base.stack_probes = StackProbeType::Inline;
    base.supported_sanitizers =
        SanitizerSet::ADDRESS | SanitizerSet::LEAK | SanitizerSet::MEMORY | SanitizerSet::THREAD;
-    // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-    base.crt_static_default = true;

    Target {
        llvm_target: "s390x-unknown-linux-musl".into(),
@@ -27,8 +27,6 @@ pub(crate) fn target() -> Target {
            features: "+v7,+thumb-mode,+thumb2,+vfp3,+neon".into(),
            max_atomic_width: Some(64),
            mcount: "\u{1}mcount".into(),
-            // FIXME(compiler-team#422): musl targets should be dynamically linked by default.
-            crt_static_default: true,
            ..base::linux_musl::opts()
        },
    }
@@ -13,7 +13,7 @@
 };
 use crate::core::config::TargetSelection;
 use crate::utils::build_stamp::{self, BuildStamp};
-use crate::{Compiler, Mode, Subcommand};
+use crate::{CodegenBackendKind, Compiler, Mode, Subcommand};

 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Std {
@@ -312,7 +312,7 @@ fn prepare_compiler_for_check(
 pub struct CodegenBackend {
    pub build_compiler: Compiler,
    pub target: TargetSelection,
-    pub backend: &'static str,
+    pub backend: CodegenBackendKind,
 }

 impl Step for CodegenBackend {
@@ -327,14 +327,14 @@ fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
    fn make_run(run: RunConfig<'_>) {
        // FIXME: only check the backend(s) that were actually selected in run.paths
        let build_compiler = prepare_compiler_for_check(run.builder, run.target, Mode::Codegen);
-        for &backend in &["cranelift", "gcc"] {
+        for backend in [CodegenBackendKind::Cranelift, CodegenBackendKind::Gcc] {
            run.builder.ensure(CodegenBackend { build_compiler, target: run.target, backend });
        }
    }

    fn run(self, builder: &Builder<'_>) {
        // FIXME: remove once https://github.com/rust-lang/rust/issues/112393 is resolved
-        if builder.build.config.vendor && self.backend == "gcc" {
+        if builder.build.config.vendor && self.backend.is_gcc() {
            println!("Skipping checking of `rustc_codegen_gcc` with vendoring enabled.");
            return;
        }
@@ -354,19 +354,22 @@ fn run(self, builder: &Builder<'_>) {

        cargo
            .arg("--manifest-path")
-            .arg(builder.src.join(format!("compiler/rustc_codegen_{backend}/Cargo.toml")));
+            .arg(builder.src.join(format!("compiler/{}/Cargo.toml", backend.crate_name())));
        rustc_cargo_env(builder, &mut cargo, target);

-        let _guard = builder.msg_check(format!("rustc_codegen_{backend}"), target, None);
+        let _guard = builder.msg_check(backend.crate_name(), target, None);

-        let stamp = build_stamp::codegen_backend_stamp(builder, build_compiler, target, backend)
+        let stamp = build_stamp::codegen_backend_stamp(builder, build_compiler, target, &backend)
            .with_prefix("check");

        run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
    }

    fn metadata(&self) -> Option<StepMetadata> {
-        Some(StepMetadata::check(self.backend, self.target).built_by(self.build_compiler))
+        Some(
+            StepMetadata::check(&self.backend.crate_name(), self.target)
+                .built_by(self.build_compiler),
+        )
    }
 }

@@ -33,7 +33,10 @@
 use crate::utils::helpers::{
    exe, get_clang_cl_resource_dir, is_debug_info, is_dylib, symlink_dir, t, up_to_date,
 };
-use crate::{CLang, Compiler, DependencyType, FileType, GitRepo, LLVM_TOOLS, Mode, debug, trace};
+use crate::{
+    CLang, CodegenBackendKind, 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)]
@@ -1330,7 +1333,7 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetS
    }

    if let Some(backend) = builder.config.default_codegen_backend(target) {
-        cargo.env("CFG_DEFAULT_CODEGEN_BACKEND", backend);
+        cargo.env("CFG_DEFAULT_CODEGEN_BACKEND", backend.name());
    }

    let libdir_relative = builder.config.libdir_relative().unwrap_or_else(|| Path::new("lib"));
@@ -1543,7 +1546,7 @@ fn run(self, builder: &Builder<'_>) {
 pub struct CodegenBackend {
    pub target: TargetSelection,
    pub compiler: Compiler,
-    pub backend: String,
+    pub backend: CodegenBackendKind,
 }

 fn needs_codegen_config(run: &RunConfig<'_>) -> bool {
@@ -1568,7 +1571,7 @@ fn is_codegen_cfg_needed(path: &TaskPath, run: &RunConfig<'_>) -> bool {
    if path.contains(CODEGEN_BACKEND_PREFIX) {
        let mut needs_codegen_backend_config = true;
        for backend in run.builder.config.codegen_backends(run.target) {
-            if path.ends_with(&(CODEGEN_BACKEND_PREFIX.to_owned() + backend)) {
+            if path.ends_with(&(CODEGEN_BACKEND_PREFIX.to_owned() + backend.name())) {
                needs_codegen_backend_config = false;
            }
        }
@@ -1602,7 +1605,7 @@ fn make_run(run: RunConfig<'_>) {
        }

        for backend in run.builder.config.codegen_backends(run.target) {
-            if backend == "llvm" {
+            if backend.is_llvm() {
                continue; // Already built as part of rustc
            }

@@ -1663,20 +1666,21 @@ fn run(self, builder: &Builder<'_>) {
        );
        cargo
            .arg("--manifest-path")
-            .arg(builder.src.join(format!("compiler/rustc_codegen_{backend}/Cargo.toml")));
+            .arg(builder.src.join(format!("compiler/{}/Cargo.toml", backend.crate_name())));
        rustc_cargo_env(builder, &mut cargo, target);

        // Ideally, we'd have a separate step for the individual codegen backends,
        // like we have in tests (test::CodegenGCC) but that would require a lot of restructuring.
        // If the logic gets more complicated, it should probably be done.
-        if backend == "gcc" {
+        if backend.is_gcc() {
            let gcc = builder.ensure(Gcc { target });
            add_cg_gcc_cargo_flags(&mut cargo, &gcc);
        }

        let tmp_stamp = BuildStamp::new(&out_dir).with_prefix("tmp");

-        let _guard = builder.msg_build(compiler, format_args!("codegen backend {backend}"), target);
+        let _guard =
+            builder.msg_build(compiler, format_args!("codegen backend {}", backend.name()), target);
        let files = run_cargo(builder, cargo, vec![], &tmp_stamp, vec![], false, false);
        if builder.config.dry_run() {
            return;
@@ -1731,7 +1735,7 @@ fn copy_codegen_backends_to_sysroot(
    }

    for backend in builder.config.codegen_backends(target) {
-        if backend == "llvm" {
+        if backend.is_llvm() {
            continue; // Already built as part of rustc
        }

@@ -2161,7 +2165,7 @@ fn run(self, builder: &Builder<'_>) -> Compiler {
        let _codegen_backend_span =
            span!(tracing::Level::DEBUG, "building requested codegen backends").entered();
        for backend in builder.config.codegen_backends(target_compiler.host) {
-            if backend == "llvm" {
+            if backend.is_llvm() {
                debug!("llvm codegen backend is already built as part of rustc");
                continue; // Already built as part of rustc
            }
@@ -32,7 +32,7 @@
    exe, is_dylib, move_file, t, target_supports_cranelift_backend, timeit,
 };
 use crate::utils::tarball::{GeneratedTarball, OverlayKind, Tarball};
-use crate::{Compiler, DependencyType, FileType, LLVM_TOOLS, Mode, trace};
+use crate::{CodegenBackendKind, Compiler, DependencyType, FileType, LLVM_TOOLS, Mode, trace};

 pub fn pkgname(builder: &Builder<'_>, component: &str) -> String {
    format!("{}-{}", component, builder.rust_package_vers())
@@ -1372,10 +1372,10 @@ fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
    }
 }

-#[derive(Debug, PartialOrd, Ord, Clone, Hash, PartialEq, Eq)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct CodegenBackend {
    pub compiler: Compiler,
-    pub backend: String,
+    pub backend: CodegenBackendKind,
 }

 impl Step for CodegenBackend {
@@ -1389,7 +1389,7 @@ fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {

    fn make_run(run: RunConfig<'_>) {
        for backend in run.builder.config.codegen_backends(run.target) {
-            if backend == "llvm" {
+            if backend.is_llvm() {
                continue; // Already built as part of rustc
            }

@@ -1412,12 +1412,11 @@ fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
            return None;
        }

-        if !builder.config.codegen_backends(self.compiler.host).contains(&self.backend.to_string())
-        {
+        if !builder.config.codegen_backends(self.compiler.host).contains(&self.backend) {
            return None;
        }

-        if self.backend == "cranelift" && !target_supports_cranelift_backend(self.compiler.host) {
+        if self.backend.is_cranelift() && !target_supports_cranelift_backend(self.compiler.host) {
            builder.info("target not supported by rustc_codegen_cranelift. skipping");
            return None;
        }
@@ -1425,15 +1424,18 @@ fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
        let compiler = self.compiler;
        let backend = self.backend;

-        let mut tarball =
-            Tarball::new(builder, &format!("rustc-codegen-{backend}"), &compiler.host.triple);
-        if backend == "cranelift" {
+        let mut tarball = Tarball::new(
+            builder,
+            &format!("rustc-codegen-{}", backend.name()),
+            &compiler.host.triple,
+        );
+        if backend.is_cranelift() {
            tarball.set_overlay(OverlayKind::RustcCodegenCranelift);
        } else {
-            panic!("Unknown backend rustc_codegen_{backend}");
+            panic!("Unknown codegen backend {}", backend.name());
        }
        tarball.is_preview(true);
-        tarball.add_legal_and_readme_to(format!("share/doc/rustc_codegen_{backend}"));
+        tarball.add_legal_and_readme_to(format!("share/doc/{}", backend.crate_name()));

        let src = builder.sysroot(compiler);
        let backends_src = builder.sysroot_codegen_backends(compiler);
@@ -1445,7 +1447,7 @@ fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
        // Don't use custom libdir here because ^lib/ will be resolved again with installer
        let backends_dst = PathBuf::from("lib").join(backends_rel);

-        let backend_name = format!("rustc_codegen_{backend}");
+        let backend_name = backend.crate_name();
        let mut found_backend = false;
        for backend in fs::read_dir(&backends_src).unwrap() {
            let file_name = backend.unwrap().file_name();
@@ -1575,7 +1577,7 @@ macro_rules! add_component {
        add_component!("analysis" => Analysis { compiler, target });
        add_component!("rustc-codegen-cranelift" => CodegenBackend {
            compiler: builder.compiler(stage, target),
-            backend: "cranelift".to_string(),
+            backend: CodegenBackendKind::Cranelift,
        });
        add_component!("llvm-bitcode-linker" => LlvmBitcodeLinker {
            build_compiler: compiler,
@@ -12,7 +12,7 @@
 use crate::utils::exec::command;
 use crate::utils::helpers::t;
 use crate::utils::tarball::GeneratedTarball;
-use crate::{Compiler, Kind};
+use crate::{CodegenBackendKind, Compiler, Kind};

 #[cfg(target_os = "illumos")]
 const SHELL: &str = "bash";
@@ -276,7 +276,7 @@ fn run($sel, $builder: &Builder<'_>) {
    RustcCodegenCranelift, alias = "rustc-codegen-cranelift", Self::should_build(_config), only_hosts: true, {
        if let Some(tarball) = builder.ensure(dist::CodegenBackend {
            compiler: self.compiler,
-            backend: "cranelift".to_string(),
+            backend: CodegenBackendKind::Cranelift,
        }) {
            install_sh(builder, "rustc-codegen-cranelift", self.compiler.stage, Some(self.target), &tarball);
        } else {
@@ -33,7 +33,7 @@
    linker_flags, t, target_supports_cranelift_backend, up_to_date,
 };
 use crate::utils::render_tests::{add_flags_and_try_run_tests, try_run_tests};
-use crate::{CLang, DocTests, GitRepo, Mode, PathSet, debug, envify};
+use crate::{CLang, CodegenBackendKind, DocTests, GitRepo, Mode, PathSet, debug, envify};

 const ADB_TEST_DIR: &str = "/data/local/tmp/work";

@@ -1786,7 +1786,9 @@ fn run(self, builder: &Builder<'_>) {
        cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.host_target));

        if let Some(codegen_backend) = builder.config.default_codegen_backend(compiler.host) {
-            cmd.arg("--codegen-backend").arg(&codegen_backend);
+            // Tells compiletest which codegen backend is used by default by the compiler.
+            // It is used to e.g. ignore tests that don't support that codegen backend.
+            cmd.arg("--codegen-backend").arg(codegen_backend.name());
        }

        if builder.build.config.llvm_enzyme {
@@ -3406,7 +3408,7 @@ fn make_run(run: RunConfig<'_>) {
            return;
        }

-        if !builder.config.codegen_backends(run.target).contains(&"cranelift".to_owned()) {
+        if !builder.config.codegen_backends(run.target).contains(&CodegenBackendKind::Cranelift) {
            builder.info("cranelift not in rust.codegen-backends. skipping");
            return;
        }
@@ -3533,7 +3535,7 @@ fn make_run(run: RunConfig<'_>) {
            return;
        }

-        if !builder.config.codegen_backends(run.target).contains(&"gcc".to_owned()) {
+        if !builder.config.codegen_backends(run.target).contains(&CodegenBackendKind::Gcc) {
            builder.info("gcc not in rust.codegen-backends. skipping");
            return;
        }
@@ -1286,7 +1286,7 @@ fn cargo(

            if let Some(limit) = limit
                && (build_compiler_stage == 0
-                    || self.config.default_codegen_backend(target).unwrap_or_default() == "llvm")
+                    || self.config.default_codegen_backend(target).unwrap_or_default().is_llvm())
            {
                rustflags.arg(&format!("-Cllvm-args=-import-instr-limit={limit}"));
            }
@@ -141,7 +141,7 @@ fn metadata(&self) -> Option<StepMetadata> {
 #[allow(unused)]
 #[derive(Debug, PartialEq, Eq)]
 pub struct StepMetadata {
-    name: &'static str,
+    name: String,
    kind: Kind,
    target: TargetSelection,
    built_by: Option<Compiler>,
@@ -151,28 +151,28 @@ pub struct StepMetadata {
 }

 impl StepMetadata {
-    pub fn build(name: &'static str, target: TargetSelection) -> Self {
+    pub fn build(name: &str, target: TargetSelection) -> Self {
        Self::new(name, target, Kind::Build)
    }

-    pub fn check(name: &'static str, target: TargetSelection) -> Self {
+    pub fn check(name: &str, target: TargetSelection) -> Self {
        Self::new(name, target, Kind::Check)
    }

-    pub fn doc(name: &'static str, target: TargetSelection) -> Self {
+    pub fn doc(name: &str, target: TargetSelection) -> Self {
        Self::new(name, target, Kind::Doc)
    }

-    pub fn dist(name: &'static str, target: TargetSelection) -> Self {
+    pub fn dist(name: &str, target: TargetSelection) -> Self {
        Self::new(name, target, Kind::Dist)
    }

-    pub fn test(name: &'static str, target: TargetSelection) -> Self {
+    pub fn test(name: &str, target: TargetSelection) -> Self {
        Self::new(name, target, Kind::Test)
    }

-    fn new(name: &'static str, target: TargetSelection, kind: Kind) -> Self {
-        Self { name, kind, target, built_by: None, stage: None, metadata: None }
+    fn new(name: &str, target: TargetSelection, kind: Kind) -> Self {
+        Self { name: name.to_string(), kind, target, built_by: None, stage: None, metadata: None }
    }

    pub fn built_by(mut self, compiler: Compiler) -> Self {
@@ -1309,8 +1309,8 @@ fn check_compiler_no_explicit_stage() {
                .path("compiler")
                .render_steps(), @r"
        [check] rustc 0 <host> -> rustc 1 <host>
-        [check] rustc 0 <host> -> cranelift 1 <host>
-        [check] rustc 0 <host> -> gcc 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_cranelift 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_gcc 1 <host>
        ");
    }

@@ -1341,8 +1341,8 @@ fn check_compiler_stage_1() {
                .stage(1)
                .render_steps(), @r"
        [check] rustc 0 <host> -> rustc 1 <host>
-        [check] rustc 0 <host> -> cranelift 1 <host>
-        [check] rustc 0 <host> -> gcc 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_cranelift 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_gcc 1 <host>
        ");
    }

@@ -1358,8 +1358,8 @@ fn check_compiler_stage_2() {
        [build] rustc 0 <host> -> rustc 1 <host>
        [build] rustc 1 <host> -> std 1 <host>
        [check] rustc 1 <host> -> rustc 2 <host>
-        [check] rustc 1 <host> -> cranelift 2 <host>
-        [check] rustc 1 <host> -> gcc 2 <host>
+        [check] rustc 1 <host> -> rustc_codegen_cranelift 2 <host>
+        [check] rustc 1 <host> -> rustc_codegen_gcc 2 <host>
        ");
    }

@@ -1377,8 +1377,8 @@ fn check_cross_compile() {
        [build] rustc 1 <host> -> std 1 <target1>
        [check] rustc 1 <host> -> rustc 2 <target1>
        [check] rustc 1 <host> -> Rustdoc 2 <target1>
-        [check] rustc 1 <host> -> cranelift 2 <target1>
-        [check] rustc 1 <host> -> gcc 2 <target1>
+        [check] rustc 1 <host> -> rustc_codegen_cranelift 2 <target1>
+        [check] rustc 1 <host> -> rustc_codegen_gcc 2 <target1>
        [check] rustc 1 <host> -> Clippy 2 <target1>
        [check] rustc 1 <host> -> Miri 2 <target1>
        [check] rustc 1 <host> -> CargoMiri 2 <target1>
@@ -1472,8 +1472,8 @@ fn check_library_skip_without_download_rustc() {
                .args(&args)
                .render_steps(), @r"
        [check] rustc 0 <host> -> rustc 1 <host>
-        [check] rustc 0 <host> -> cranelift 1 <host>
-        [check] rustc 0 <host> -> gcc 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_cranelift 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_gcc 1 <host>
        ");
    }

@@ -1557,8 +1557,8 @@ fn check_codegen() {
                .path("rustc_codegen_cranelift")
                .render_steps(), @r"
        [check] rustc 0 <host> -> rustc 1 <host>
-        [check] rustc 0 <host> -> cranelift 1 <host>
-        [check] rustc 0 <host> -> gcc 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_cranelift 1 <host>
+        [check] rustc 0 <host> -> rustc_codegen_gcc 1 <host>
        ");
    }

@@ -51,7 +51,7 @@
 use crate::utils::channel;
 use crate::utils::exec::{ExecutionContext, command};
 use crate::utils::helpers::{exe, get_host_target};
-use crate::{GitInfo, OnceLock, TargetSelection, check_ci_llvm, helpers, t};
+use crate::{CodegenBackendKind, GitInfo, OnceLock, TargetSelection, check_ci_llvm, helpers, t};

 /// Each path in this list is considered "allowed" in the `download-rustc="if-unchanged"` logic.
 /// This means they can be modified and changes to these paths should never trigger a compiler build
@@ -208,7 +208,7 @@ pub struct Config {
    pub rustc_default_linker: Option<String>,
    pub rust_optimize_tests: bool,
    pub rust_dist_src: bool,
-    pub rust_codegen_backends: Vec<String>,
+    pub rust_codegen_backends: Vec<CodegenBackendKind>,
    pub rust_verify_llvm_ir: bool,
    pub rust_thin_lto_import_instr_limit: Option<u32>,
    pub rust_randomize_layout: bool,
@@ -350,7 +350,7 @@ pub fn default_opts() -> Config {
            channel: "dev".to_string(),
            codegen_tests: true,
            rust_dist_src: true,
-            rust_codegen_backends: vec!["llvm".to_owned()],
+            rust_codegen_backends: vec![CodegenBackendKind::Llvm],
            deny_warnings: true,
            bindir: "bin".into(),
            dist_include_mingw_linker: true,
@@ -1747,7 +1747,7 @@ pub fn profiler_enabled(&self, target: TargetSelection) -> bool {
            .unwrap_or(self.profiler)
    }

-    pub fn codegen_backends(&self, target: TargetSelection) -> &[String] {
+    pub fn codegen_backends(&self, target: TargetSelection) -> &[CodegenBackendKind] {
        self.target_config
            .get(&target)
            .and_then(|cfg| cfg.codegen_backends.as_deref())
@@ -1758,7 +1758,7 @@ pub fn jemalloc(&self, target: TargetSelection) -> bool {
        self.target_config.get(&target).and_then(|cfg| cfg.jemalloc).unwrap_or(self.jemalloc)
    }

-    pub fn default_codegen_backend(&self, target: TargetSelection) -> Option<String> {
+    pub fn default_codegen_backend(&self, target: TargetSelection) -> Option<CodegenBackendKind> {
        self.codegen_backends(target).first().cloned()
    }

@@ -1774,7 +1774,7 @@ pub fn optimized_compiler_builtins(&self, target: TargetSelection) -> bool {
    }

    pub fn llvm_enabled(&self, target: TargetSelection) -> bool {
-        self.codegen_backends(target).contains(&"llvm".to_owned())
+        self.codegen_backends(target).contains(&CodegenBackendKind::Llvm)
    }

    pub fn llvm_libunwind(&self, target: TargetSelection) -> LlvmLibunwind {
@@ -11,7 +11,9 @@
    DebuginfoLevel, Merge, ReplaceOpt, RustcLto, StringOrBool, set, threads_from_config,
 };
 use crate::flags::Warnings;
-use crate::{BTreeSet, Config, HashSet, PathBuf, TargetSelection, define_config, exit};
+use crate::{
+    BTreeSet, CodegenBackendKind, Config, HashSet, PathBuf, TargetSelection, define_config, exit,
+};

 define_config! {
    /// TOML representation of how the Rust build is configured.
@@ -389,9 +391,13 @@ macro_rules! warn {
    Ok(())
 }

-pub(crate) const VALID_CODEGEN_BACKENDS: &[&str] = &["llvm", "cranelift", "gcc"];
+pub(crate) const BUILTIN_CODEGEN_BACKENDS: &[&str] = &["llvm", "cranelift", "gcc"];

-pub(crate) fn validate_codegen_backends(backends: Vec<String>, section: &str) -> Vec<String> {
+pub(crate) fn parse_codegen_backends(
+    backends: Vec<String>,
+    section: &str,
+) -> Vec<CodegenBackendKind> {
+    let mut found_backends = vec![];
    for backend in &backends {
        if let Some(stripped) = backend.strip_prefix(CODEGEN_BACKEND_PREFIX) {
            panic!(
@@ -400,14 +406,21 @@ pub(crate) fn validate_codegen_backends(backends: Vec<String>, section: &str) ->
                Please, use '{stripped}' instead."
            )
        }
-        if !VALID_CODEGEN_BACKENDS.contains(&backend.as_str()) {
+        if !BUILTIN_CODEGEN_BACKENDS.contains(&backend.as_str()) {
            println!(
                "HELP: '{backend}' for '{section}.codegen-backends' might fail. \
-                List of known good values: {VALID_CODEGEN_BACKENDS:?}"
+                List of known codegen backends: {BUILTIN_CODEGEN_BACKENDS:?}"
            );
        }
+        let backend = match backend.as_str() {
+            "llvm" => CodegenBackendKind::Llvm,
+            "cranelift" => CodegenBackendKind::Cranelift,
+            "gcc" => CodegenBackendKind::Gcc,
+            backend => CodegenBackendKind::Custom(backend.to_string()),
+        };
+        found_backends.push(backend);
    }
-    backends
+    found_backends
 }

 #[cfg(not(test))]
@@ -609,7 +622,7 @@ pub fn apply_rust_config(&mut self, toml_rust: Option<Rust>, warnings: Warnings)
                llvm_libunwind.map(|v| v.parse().expect("failed to parse rust.llvm-libunwind"));
            set(
                &mut self.rust_codegen_backends,
-                codegen_backends.map(|backends| validate_codegen_backends(backends, "rust")),
+                codegen_backends.map(|backends| parse_codegen_backends(backends, "rust")),
            );

            self.rust_codegen_units = codegen_units.map(threads_from_config);
@@ -16,9 +16,9 @@

 use serde::{Deserialize, Deserializer};

-use crate::core::config::toml::rust::validate_codegen_backends;
+use crate::core::config::toml::rust::parse_codegen_backends;
 use crate::core::config::{LlvmLibunwind, Merge, ReplaceOpt, SplitDebuginfo, StringOrBool};
-use crate::{Config, HashSet, PathBuf, TargetSelection, define_config, exit};
+use crate::{CodegenBackendKind, Config, HashSet, PathBuf, TargetSelection, define_config, exit};

 define_config! {
    /// TOML representation of how each build target is configured.
@@ -76,7 +76,7 @@ pub struct Target {
    pub qemu_rootfs: Option<PathBuf>,
    pub runner: Option<String>,
    pub no_std: bool,
-    pub codegen_backends: Option<Vec<String>>,
+    pub codegen_backends: Option<Vec<CodegenBackendKind>>,
    pub optimized_compiler_builtins: Option<bool>,
    pub jemalloc: Option<bool>,
 }
@@ -144,7 +144,7 @@ pub fn apply_target_config(&mut self, toml_target: Option<HashMap<String, TomlTa
                target.jemalloc = cfg.jemalloc;
                if let Some(backends) = cfg.codegen_backends {
                    target.codegen_backends =
-                        Some(validate_codegen_backends(backends, &format!("target.{triple}")))
+                        Some(parse_codegen_backends(backends, &format!("target.{triple}")))
                }

                target.split_debuginfo = cfg.split_debuginfo.as_ref().map(|v| {
@@ -123,6 +123,46 @@ fn eq(&self, other: &Self) -> bool {
    }
 }

+/// Represents a codegen backend.
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Default)]
+pub enum CodegenBackendKind {
+    #[default]
+    Llvm,
+    Cranelift,
+    Gcc,
+    Custom(String),
+}
+
+impl CodegenBackendKind {
+    /// Name of the codegen backend, as identified in the `compiler` directory
+    /// (`rustc_codegen_<name>`).
+    pub fn name(&self) -> &str {
+        match self {
+            CodegenBackendKind::Llvm => "llvm",
+            CodegenBackendKind::Cranelift => "cranelift",
+            CodegenBackendKind::Gcc => "gcc",
+            CodegenBackendKind::Custom(name) => name,
+        }
+    }
+
+    /// Name of the codegen backend's crate, e.g. `rustc_codegen_cranelift`.
+    pub fn crate_name(&self) -> String {
+        format!("rustc_codegen_{}", self.name())
+    }
+
+    pub fn is_llvm(&self) -> bool {
+        matches!(self, Self::Llvm)
+    }
+
+    pub fn is_cranelift(&self) -> bool {
+        matches!(self, Self::Cranelift)
+    }
+
+    pub fn is_gcc(&self) -> bool {
+        matches!(self, Self::Gcc)
+    }
+}
+
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
 pub enum DocTests {
    /// Run normal tests and doc tests (default).
@@ -10,7 +10,7 @@
 use crate::core::builder::Builder;
 use crate::core::config::TargetSelection;
 use crate::utils::helpers::{hex_encode, mtime};
-use crate::{Compiler, Mode, helpers, t};
+use crate::{CodegenBackendKind, Compiler, Mode, helpers, t};

 #[cfg(test)]
 mod tests;
@@ -129,10 +129,10 @@ pub fn codegen_backend_stamp(
    builder: &Builder<'_>,
    compiler: Compiler,
    target: TargetSelection,
-    backend: &str,
+    backend: &CodegenBackendKind,
 ) -> BuildStamp {
    BuildStamp::new(&builder.cargo_out(compiler, Mode::Codegen, target))
-        .with_prefix(&format!("librustc_codegen_{backend}"))
+        .with_prefix(&format!("lib{}", backend.crate_name()))
 }

 /// Cargo's output path for the standard library in a given stage, compiled
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13264
+
 //@ run-pass
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11709
+
 //@ run-pass
 #![allow(dead_code)]

@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12041
+
 use std::sync::mpsc::channel;
 use std::thread;

@@ -1,5 +1,5 @@
 error[E0382]: use of moved value: `tx`
-  --> $DIR/issue-12041.rs:8:22
+  --> $DIR/moved-value-in-thread-loop-12041.rs:10:22
   |
 LL |             let tx = tx;
   |                      ^^ value moved here, in previous iteration of loop
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12033
+
 //@ run-pass
 use std::cell::RefCell;

@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11869
+
 //@ check-pass
 #![allow(dead_code)]

@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12127
+
 #![feature(unboxed_closures, tuple_trait)]

 fn to_fn_once<A:std::marker::Tuple,F:FnOnce<A>>(f: F) -> F { f }
@@ -1,5 +1,5 @@
 error[E0382]: use of moved value: `f`
-  --> $DIR/issue-12127.rs:11:9
+  --> $DIR/fnonce-moved-twice-12127.rs:13:9
   |
 LL |         f();
   |         --- `f` moved due to this call
@@ -7,11 +7,11 @@ LL |         f();
   |         ^ value used here after move
   |
 note: this value implements `FnOnce`, which causes it to be moved when called
-  --> $DIR/issue-12127.rs:10:9
+  --> $DIR/fnonce-moved-twice-12127.rs:12:9
   |
 LL |         f();
   |         ^
-   = note: move occurs because `f` has type `{closure@$DIR/issue-12127.rs:8:24: 8:30}`, which does not implement the `Copy` trait
+   = note: move occurs because `f` has type `{closure@$DIR/fnonce-moved-twice-12127.rs:10:24: 10:30}`, which does not implement the `Copy` trait

 error: aborting due to 1 previous error

@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11958
+
 //@ run-pass

 // We shouldn't need to rebind a moved upvar as mut if it's already
@@ -1,5 +1,5 @@
 warning: value assigned to `x` is never read
-  --> $DIR/issue-11958.rs:8:36
+  --> $DIR/moved-upvar-mut-rebind-11958.rs:10:36
   |
 LL |     let _thunk = Box::new(move|| { x = 2; });
   |                                    ^
@@ -8,7 +8,7 @@ LL |     let _thunk = Box::new(move|| { x = 2; });
   = note: `#[warn(unused_assignments)]` on by default

 warning: unused variable: `x`
-  --> $DIR/issue-11958.rs:8:36
+  --> $DIR/moved-upvar-mut-rebind-11958.rs:10:36
   |
 LL |     let _thunk = Box::new(move|| { x = 2; });
   |                                    ^
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12744
+
 //@ run-pass
 fn main() {
    fn test() -> Box<dyn std::any::Any + 'static> { Box::new(1) }
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12860
+
 //@ run-pass
 use std::collections::HashSet;

@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13446
+
 // Used to cause ICE

 static VEC: [u32; 256] = vec![];
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-13446.rs:3:26
+  --> $DIR/vec-macro-in-static-array.rs:5:26
   |
 LL | static VEC: [u32; 256] = vec![];
   |                          ^^^^^^ expected `[u32; 256]`, found `Vec<_>`
@@ -0,0 +1,49 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13259
+
+//@ run-pass
+
+#[cfg(windows)]
+mod imp {
+    type LPVOID = *mut u8;
+    type DWORD = u32;
+    type LPWSTR = *mut u16;
+
+    extern "system" {
+        fn FormatMessageW(
+            flags: DWORD,
+            lpSrc: LPVOID,
+            msgId: DWORD,
+            langId: DWORD,
+            buf: LPWSTR,
+            nsize: DWORD,
+            args: *const u8,
+        ) -> DWORD;
+    }
+
+    pub fn test() {
+        let mut buf: [u16; 50] = [0; 50];
+        let ret = unsafe {
+            FormatMessageW(
+                0x1000,
+                core::ptr::null_mut(),
+                1,
+                0x400,
+                buf.as_mut_ptr(),
+                buf.len() as u32,
+                core::ptr::null(),
+            )
+        };
+        // On some 32-bit Windowses (Win7-8 at least) this will panic with segmented
+        // stacks taking control of pvArbitrary
+        assert!(ret != 0);
+    }
+}
+
+#[cfg(not(windows))]
+mod imp {
+    pub fn test() {}
+}
+
+fn main() {
+    imp::test()
+}
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13105
+
 //@ edition: 2015
 //@ check-pass

@@ -1,39 +0,0 @@
-//@ run-pass
-
-#[cfg(windows)]
-mod imp {
-    type LPVOID = *mut u8;
-    type DWORD = u32;
-    type LPWSTR = *mut u16;
-
-    extern "system" {
-        fn FormatMessageW(flags: DWORD,
-                          lpSrc: LPVOID,
-                          msgId: DWORD,
-                          langId: DWORD,
-                          buf: LPWSTR,
-                          nsize: DWORD,
-                          args: *const u8)
-                          -> DWORD;
-    }
-
-    pub fn test() {
-        let mut buf: [u16; 50] = [0; 50];
-        let ret = unsafe {
-            FormatMessageW(0x1000, core::ptr::null_mut(), 1, 0x400,
-                           buf.as_mut_ptr(), buf.len() as u32, core::ptr::null())
-        };
-        // On some 32-bit Windowses (Win7-8 at least) this will panic with segmented
-        // stacks taking control of pvArbitrary
-        assert!(ret != 0);
-    }
-}
-
-#[cfg(not(windows))]
-mod imp {
-    pub fn test() { }
-}
-
-fn main() {
-    imp::test()
-}
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12677
+
 //@ run-pass

 fn main() {
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13058
+
 use std::ops::Range;

 trait Itble<'r, T, I: Iterator<Item=T>> { fn iter(&'r self) -> I; }
@@ -1,5 +1,5 @@
 error[E0621]: explicit lifetime required in the type of `cont`
-  --> $DIR/issue-13058.rs:14:21
+  --> $DIR/iterator-trait-lifetime-error-13058.rs:16:21
   |
 LL |     let cont_iter = cont.iter();
   |                     ^^^^^^^^^^^ lifetime `'r` required
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13167
+
 //@ check-pass
 //@ revisions: current next
 //@ ignore-compare-mode-next-solver (explicit revisions)
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13323
+
 //@ run-pass

 struct StrWrap {
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13405
+
 //@ check-pass
 #![allow(dead_code)]
 #![allow(unused_variables)]
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11740
+
 //@ check-pass

 struct Attr {
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11844
+
 fn main() {
    let a = Some(Box::new(1));
    match a {
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-11844.rs:4:9
+  --> $DIR/option-result-mismatch-11844.rs:6:9
   |
 LL |     match a {
   |           - this expression has type `Option<Box<{integer}>>`
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13466
+
 // Regression test for #13466

 //@ dont-require-annotations: NOTE
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-13466.rs:10:9
+  --> $DIR/option-result-type-param-mismatch-13466.rs:12:9
   |
 LL |     let _x: usize = match Some(1) {
   |                           ------- this expression has type `Option<{integer}>`
@@ -10,7 +10,7 @@ LL |         Ok(u) => u,
              found enum `Result<_, _>`

 error[E0308]: mismatched types
-  --> $DIR/issue-13466.rs:16:9
+  --> $DIR/option-result-type-param-mismatch-13466.rs:18:9
   |
 LL |     let _x: usize = match Some(1) {
   |                           ------- this expression has type `Option<{integer}>`
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13027
+
 //@ run-pass

 // Tests that match expression handles overlapped literal and range
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12567
+
 fn match_vecs<'a, T>(l1: &'a [T], l2: &'a [T]) {
    match (l1, l2) {
    //~^ ERROR: cannot move out of type `[T]`, a non-copy slice
@@ -1,5 +1,5 @@
 error[E0508]: cannot move out of type `[T]`, a non-copy slice
-  --> $DIR/issue-12567.rs:2:11
+  --> $DIR/slice-move-out-error-12567.rs:4:11
   |
 LL |     match (l1, l2) {
   |           ^^^^^^^^ cannot move out of here
@@ -23,7 +23,7 @@ LL +         (&[hd1, ..], [hd2, ..])
   |

 error[E0508]: cannot move out of type `[T]`, a non-copy slice
-  --> $DIR/issue-12567.rs:2:11
+  --> $DIR/slice-move-out-error-12567.rs:4:11
   |
 LL |     match (l1, l2) {
   |           ^^^^^^^^ cannot move out of here
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12285
+
 //@ run-pass

 struct S;
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12920
+
 //@ run-fail
 //@ error-pattern:explicit panic
 //@ needs-subprocess
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13407
+
 mod A {
    struct C;
 }
@@ -1,17 +1,17 @@
 error[E0603]: unit struct `C` is private
-  --> $DIR/issue-13407.rs:6:8
+  --> $DIR/private-unit-struct-assignment.rs:8:8
   |
 LL |     A::C = 1;
   |        ^ private unit struct
   |
 note: the unit struct `C` is defined here
-  --> $DIR/issue-13407.rs:2:5
+  --> $DIR/private-unit-struct-assignment.rs:4:5
   |
 LL |     struct C;
   |     ^^^^^^^^^

 error[E0308]: mismatched types
-  --> $DIR/issue-13407.rs:6:5
+  --> $DIR/private-unit-struct-assignment.rs:8:5
   |
 LL |     struct C;
   |     -------- unit struct defined here
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12729
+
 //@ edition: 2015
 //@ check-pass
 #![allow(dead_code)]
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11820
+
 //@ run-pass

 #![allow(noop_method_call)]
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13214
+
 //@ build-pass
 #![allow(dead_code)]
 // defining static with struct that contains enum
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13204
+
 //@ run-pass
 #![allow(unused_mut)]
 // Test that when instantiating trait default methods, typeck handles
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13434
+
 //@ run-pass
 #[derive(Debug)]
 struct MyStruct;
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12909
+
 //@ run-pass
 #![allow(unused_variables)]

@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/12863
+
 mod foo { pub fn bar() {} }

 fn main() {
@@ -1,5 +1,5 @@
 error[E0532]: expected unit struct, unit variant or constant, found function `foo::bar`
-  --> $DIR/issue-12863.rs:5:9
+  --> $DIR/function-in-pattern-error-12863.rs:7:9
   |
 LL |         foo::bar => {}
   |         ^^^^^^^^ not a unit struct, unit variant or constant
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13359
+
 //@ dont-require-annotations: NOTE

 fn foo(_s: i16) { }
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-13359.rs:8:9
+  --> $DIR/isize-usize-mismatch-error.rs:10:9
   |
 LL |     foo(1*(1 as isize));
   |     --- ^^^^^^^^^^^^^^ expected `i16`, found `isize`
@@ -7,7 +7,7 @@ LL |     foo(1*(1 as isize));
   |     arguments to this function are incorrect
   |
 note: function defined here
-  --> $DIR/issue-13359.rs:3:4
+  --> $DIR/isize-usize-mismatch-error.rs:5:4
   |
 LL | fn foo(_s: i16) { }
   |    ^^^ -------
@@ -17,7 +17,7 @@ LL |     foo((1*(1 as isize)).try_into().unwrap());
   |         +              +++++++++++++++++++++

 error[E0308]: mismatched types
-  --> $DIR/issue-13359.rs:12:9
+  --> $DIR/isize-usize-mismatch-error.rs:14:9
   |
 LL |     bar(1*(1 as usize));
   |     --- ^^^^^^^^^^^^^^ expected `u32`, found `usize`
@@ -25,7 +25,7 @@ LL |     bar(1*(1 as usize));
   |     arguments to this function are incorrect
   |
 note: function defined here
-  --> $DIR/issue-13359.rs:5:4
+  --> $DIR/isize-usize-mismatch-error.rs:7:4
   |
 LL | fn bar(_s: u32) { }
   |    ^^^ -------
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/11771
+
 fn main() {
    let x = ();
    1 +
@@ -1,5 +1,5 @@
 error[E0277]: cannot add `()` to `{integer}`
-  --> $DIR/issue-11771.rs:3:7
+  --> $DIR/unit-type-add-error-11771.rs:5:7
   |
 LL |     1 +
   |       ^ no implementation for `{integer} + ()`
@@ -17,7 +17,7 @@ LL |     1 +
           and 56 others

 error[E0277]: cannot add `()` to `{integer}`
-  --> $DIR/issue-11771.rs:8:7
+  --> $DIR/unit-type-add-error-11771.rs:10:7
   |
 LL |     1 +
   |       ^ no implementation for `{integer} + ()`
@@ -1,3 +1,5 @@
+//! Regression test for https://github.com/rust-lang/rust/issues/13202
+
 //@ run-fail
 //@ error-pattern:bad input
 //@ needs-subprocess
@@ -1007,10 +1007,6 @@ cc = [
 message = "Some changes occurred in GUI tests."
 cc = ["@GuillaumeGomez"]

-[mentions."tests/run-make/"]
-message = "This PR modifies `run-make` tests."
-cc = ["@jieyouxu"]
-
 [mentions."tests/auxiliary/minicore.rs"]
 message = "This PR modifies `tests/auxiliary/minicore.rs`."
 cc = ["@jieyouxu"]
@@ -1113,10 +1109,6 @@ Otherwise, you can ignore this comment.
 [mentions."src/tools/x"]
 message = "`src/tools/x` was changed. Bump version of Cargo.toml in `src/tools/x` so tidy will suggest installing the new version."

-[mentions."src/tools/tidy"]
-message = "There are changes to the `tidy` tool."
-cc = ["@jieyouxu"]
-
 [mentions."src/tools/tidy/src/deps.rs"]
 message = "The list of allowed third-party dependencies may have been modified! You must ensure that any new dependencies have compatible licenses before merging."
 cc = ["@davidtwco", "@wesleywiser"]