Auto merge of #93854 - matthiaskrgr:rollup-bh2a85j, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #92670 (add kernel target for RustyHermit)
 - #93756 (Support custom options for LLVM build)
 - #93802 (fix oversight in the `min_const_generics` checks)
 - #93808 (Remove first headings indent)
 - #93824 (Stabilize cfg_target_has_atomic)
 - #93830 (Refactor sidebar printing code)
 - #93843 (kmc-solid: Fix wait queue manipulation errors in the `Condvar` implementation)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_feature/src/accepted.rs

@@ -72,6 +72,8 @@ declare_features! (
     (accepted, cfg_doctest, "1.40.0", Some(62210), None),
     /// Allows `cfg(target_feature = "...")`.
     (accepted, cfg_target_feature, "1.27.0", Some(29717), None),
+    /// Allows `cfg(target_has_atomic = "...")`.
+    (accepted, cfg_target_has_atomic, "1.60.0", Some(32976), None),
     /// Allows `cfg(target_vendor = "...")`.
     (accepted, cfg_target_vendor, "1.33.0", Some(29718), None),
     /// Allows implementing `Clone` for closures where possible (RFC 2132).

compiler/rustc_feature/src/active.rs

@@ -309,8 +309,8 @@ declare_features! (
     (active, cfg_sanitize, "1.41.0", Some(39699), None),
     /// Allows `cfg(target_abi = "...")`.
     (active, cfg_target_abi, "1.55.0", Some(80970), None),
-    /// Allows `cfg(target_has_atomic = "...")`.
-    (active, cfg_target_has_atomic, "1.9.0", Some(32976), None),
+    /// Allows `cfg(target_has_atomic_equal_alignment = "...")`.
+    (active, cfg_target_has_atomic_equal_alignment, "1.60.0", Some(93822), None),
     /// Allows `cfg(target_thread_local)`.
     (active, cfg_target_thread_local, "1.7.0", Some(29594), None),
     /// Allow conditional compilation depending on rust version

compiler/rustc_feature/src/builtin_attrs.rs

@@ -26,12 +26,10 @@ const GATED_CFGS: &[GatedCfg] = &[
     // (name in cfg, feature, function to check if the feature is enabled)
     (sym::target_abi, sym::cfg_target_abi, cfg_fn!(cfg_target_abi)),
     (sym::target_thread_local, sym::cfg_target_thread_local, cfg_fn!(cfg_target_thread_local)),
-    (sym::target_has_atomic, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
-    (sym::target_has_atomic_load_store, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
     (
         sym::target_has_atomic_equal_alignment,
-        sym::cfg_target_has_atomic,
-        cfg_fn!(cfg_target_has_atomic),
+        sym::cfg_target_has_atomic_equal_alignment,
+        cfg_fn!(cfg_target_has_atomic_equal_alignment),
     ),
     (sym::sanitize, sym::cfg_sanitize, cfg_fn!(cfg_sanitize)),
     (sym::version, sym::cfg_version, cfg_fn!(cfg_version)),

compiler/rustc_span/src/symbol.rs

@@ -421,6 +421,7 @@ symbols! {
         cfg_target_abi,
         cfg_target_feature,
         cfg_target_has_atomic,
+        cfg_target_has_atomic_equal_alignment,
         cfg_target_thread_local,
         cfg_target_vendor,
         cfg_version,

compiler/rustc_target/src/spec/aarch64_unknown_hermit.rs

@@ -3,6 +3,7 @@ use crate::spec::Target;
 pub fn target() -> Target {
     let mut base = super::hermit_base::opts();
     base.max_atomic_width = Some(128);
+    base.features = "+strict-align,+neon,+fp-armv8".to_string();
 
     Target {
         llvm_target: "aarch64-unknown-hermit".to_string(),

compiler/rustc_target/src/spec/aarch64_unknown_none_hermitkernel.rs

@@ -0,0 +1,16 @@
+use crate::spec::Target;
+
+pub fn target() -> Target {
+    let mut base = super::hermit_kernel_base::opts();
+    base.max_atomic_width = Some(128);
+    base.abi = "softfloat".to_string();
+    base.features = "+strict-align,-neon,-fp-armv8".to_string();
+
+    Target {
+        llvm_target: "aarch64-unknown-hermit".to_string(),
+        pointer_width: 64,
+        data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
+        arch: "aarch64".to_string(),
+        options: base,
+    }
+}

compiler/rustc_target/src/spec/mod.rs

@@ -964,6 +964,7 @@ supported_targets! {
     ("aarch64-unknown-hermit", aarch64_unknown_hermit),
     ("x86_64-unknown-hermit", x86_64_unknown_hermit),
 
+    ("aarch64-unknown-none-hermitkernel", aarch64_unknown_none_hermitkernel),
     ("x86_64-unknown-none-hermitkernel", x86_64_unknown_none_hermitkernel),
 
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),

compiler/rustc_typeck/src/astconv/mod.rs

@@ -2281,8 +2281,27 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 assert_eq!(opt_self_ty, None);
                 self.prohibit_generics(path.segments);
                 // Try to evaluate any array length constants.
-                let normalized_ty = self.normalize_ty(span, tcx.at(span).type_of(def_id));
-                if forbid_generic && normalized_ty.needs_subst() {
+                let ty = tcx.at(span).type_of(def_id);
+                // HACK(min_const_generics): Forbid generic `Self` types
+                // here as we can't easily do that during nameres.
+                //
+                // We do this before normalization as we otherwise allow
+                // ```rust
+                // trait AlwaysApplicable { type Assoc; }
+                // impl<T: ?Sized> AlwaysApplicable for T { type Assoc = usize; }
+                //
+                // trait BindsParam<T> {
+                //     type ArrayTy;
+                // }
+                // impl<T> BindsParam<T> for <T as AlwaysApplicable>::Assoc {
+                //    type ArrayTy = [u8; Self::MAX];
+                // }
+                // ```
+                // Note that the normalization happens in the param env of
+                // the anon const, which is empty. This is why the
+                // `AlwaysApplicable` impl needs a `T: ?Sized` bound for
+                // this to compile if we were to normalize here.
+                if forbid_generic && ty.needs_subst() {
                     let mut err = tcx.sess.struct_span_err(
                         path.span,
                         "generic `Self` types are currently not permitted in anonymous constants",
@@ -2297,7 +2316,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     err.emit();
                     tcx.ty_error()
                 } else {
-                    normalized_ty
+                    self.normalize_ty(span, ty)
                 }
             }
             Res::Def(DefKind::AssocTy, def_id) => {

config.toml.example

@@ -157,6 +157,9 @@ changelog-seen = 2
 # Whether to build the clang compiler.
 #clang = false
 
+# Custom CMake defines to set when building LLVM.
+#build-config = {}
+
 # =============================================================================
 # General build configuration options
 # =============================================================================

library/alloc/src/lib.rs

@@ -140,7 +140,7 @@
 #![feature(associated_type_bounds)]
 #![feature(box_syntax)]
 #![feature(cfg_sanitize)]
-#![feature(cfg_target_has_atomic)]
+#![cfg_attr(bootstrap, feature(cfg_target_has_atomic))]
 #![feature(const_deref)]
 #![feature(const_fn_trait_bound)]
 #![feature(const_mut_refs)]

library/core/src/lib.rs

@@ -155,7 +155,8 @@
 #![feature(allow_internal_unstable)]
 #![feature(associated_type_bounds)]
 #![feature(auto_traits)]
-#![feature(cfg_target_has_atomic)]
+#![cfg_attr(bootstrap, feature(cfg_target_has_atomic))]
+#![cfg_attr(not(bootstrap), feature(cfg_target_has_atomic_equal_alignment))]
 #![feature(const_fn_floating_point_arithmetic)]
 #![feature(const_fn_fn_ptr_basics)]
 #![feature(const_fn_trait_bound)]

library/core/tests/lib.rs

@@ -7,7 +7,7 @@
 #![feature(box_syntax)]
 #![feature(cell_update)]
 #![feature(cfg_panic)]
-#![feature(cfg_target_has_atomic)]
+#![cfg_attr(bootstrap, feature(cfg_target_has_atomic))]
 #![feature(const_assume)]
 #![feature(const_black_box)]
 #![feature(const_bool_to_option)]

library/std/src/lib.rs

@@ -242,7 +242,7 @@
 #![feature(c_variadic)]
 #![feature(cfg_accessible)]
 #![feature(cfg_eval)]
-#![feature(cfg_target_has_atomic)]
+#![cfg_attr(bootstrap, feature(cfg_target_has_atomic))]
 #![feature(cfg_target_thread_local)]
 #![feature(char_error_internals)]
 #![feature(char_internals)]

library/std/src/sys/itron/condvar.rs

@@ -15,10 +15,12 @@ unsafe impl Sync for Condvar {}
 pub type MovableCondvar = Condvar;
 
 impl Condvar {
+    #[inline]
     pub const fn new() -> Condvar {
         Condvar { waiters: SpinMutex::new(waiter_queue::WaiterQueue::new()) }
     }
 
+    #[inline]
     pub unsafe fn init(&mut self) {}
 
     pub unsafe fn notify_one(&self) {
@@ -190,7 +192,7 @@ mod waiter_queue {
                     let insert_after = {
                         let mut cursor = head.last;
                         loop {
-                            if waiter.priority <= cursor.as_ref().priority {
+                            if waiter.priority >= cursor.as_ref().priority {
                                 // `cursor` and all previous waiters have the same or higher
                                 // priority than `current_task_priority`. Insert the new
                                 // waiter right after `cursor`.
@@ -206,14 +208,16 @@ mod waiter_queue {
 
                     if let Some(mut insert_after) = insert_after {
                         // Insert `waiter` after `insert_after`
-                        let insert_before = insert_after.as_ref().prev;
+                        let insert_before = insert_after.as_ref().next;
 
                         waiter.prev = Some(insert_after);
                         insert_after.as_mut().next = Some(waiter_ptr);
 
                         waiter.next = insert_before;
                         if let Some(mut insert_before) = insert_before {
                             insert_before.as_mut().prev = Some(waiter_ptr);
+                        } else {
+                            head.last = waiter_ptr;
                         }
                     } else {
                         // Insert `waiter` to the front
@@ -240,11 +244,11 @@ mod waiter_queue {
                     match (waiter.prev, waiter.next) {
                         (Some(mut prev), Some(mut next)) => {
                             prev.as_mut().next = Some(next);
-                            next.as_mut().next = Some(prev);
+                            next.as_mut().prev = Some(prev);
                         }
                         (None, Some(mut next)) => {
                             head.first = next;
-                            next.as_mut().next = None;
+                            next.as_mut().prev = None;
                         }
                         (Some(mut prev), None) => {
                             prev.as_mut().next = None;
@@ -271,6 +275,7 @@ mod waiter_queue {
             unsafe { waiter.as_ref().task != 0 }
         }
 
+        #[inline]
         pub fn pop_front(&mut self) -> Option<abi::ID> {
             unsafe {
                 let head = self.head.as_mut()?;

src/bootstrap/config.rs

@@ -108,6 +108,7 @@ pub struct Config {
     pub llvm_polly: bool,
     pub llvm_clang: bool,
     pub llvm_from_ci: bool,
+    pub llvm_build_config: HashMap<String, String>,
 
     pub use_lld: bool,
     pub lld_enabled: bool,
@@ -477,6 +478,7 @@ derive_merge! {
         polly: Option<bool>,
         clang: Option<bool>,
         download_ci_llvm: Option<StringOrBool>,
+        build_config: Option<HashMap<String, String>>,
     }
 }
 
@@ -807,6 +809,7 @@ impl Config {
             config.llvm_allow_old_toolchain = llvm.allow_old_toolchain.unwrap_or(false);
             config.llvm_polly = llvm.polly.unwrap_or(false);
             config.llvm_clang = llvm.clang.unwrap_or(false);
+            config.llvm_build_config = llvm.build_config.clone().unwrap_or(Default::default());
             config.llvm_from_ci = match llvm.download_ci_llvm {
                 Some(StringOrBool::String(s)) => {
                     assert!(s == "if-available", "unknown option `{}` for download-ci-llvm", s);
@@ -876,6 +879,7 @@ impl Config {
                 check_ci_llvm!(llvm.allow_old_toolchain);
                 check_ci_llvm!(llvm.polly);
                 check_ci_llvm!(llvm.clang);
+                check_ci_llvm!(llvm.build_config);
                 check_ci_llvm!(llvm.plugins);
 
                 // CI-built LLVM can be either dynamic or static.

src/bootstrap/native.rs

@@ -353,6 +353,10 @@ impl Step for Llvm {
 
         configure_cmake(builder, target, &mut cfg, true);
 
+        for (key, val) in &builder.config.llvm_build_config {
+            cfg.define(key, val);
+        }
+
         // FIXME: we don't actually need to build all LLVM tools and all LLVM
         //        libraries here, e.g., we just want a few components and a few
         //        tools. Figure out how to filter them down and only build the right

src/doc/rustc/src/SUMMARY.md

@@ -17,6 +17,7 @@
     - [aarch64-apple-ios-sim](platform-support/aarch64-apple-ios-sim.md)
     - [armv7-unknown-linux-uclibceabi](platform-support/armv7-unknown-linux-uclibceabi.md)
     - [armv7-unknown-linux-uclibceabihf](platform-support/armv7-unknown-linux-uclibceabihf.md)
+    - [aarch64-unknown-none-hermitkernel](platform-support/aarch64-unknown-none-hermitkernel.md)
     - [\*-kmc-solid_\*](platform-support/kmc-solid.md)
     - [*-unknown-openbsd](platform-support/openbsd.md)
     - [x86_64-unknown-none](platform-support/x86_64-unknown-none.md)

src/doc/rustc/src/platform-support.md

@@ -204,7 +204,8 @@ target | std | host | notes
 `aarch64-apple-tvos` | * |  | ARM64 tvOS
 [`aarch64-kmc-solid_asp3`](platform-support/kmc-solid.md) | ✓ |  | ARM64 SOLID with TOPPERS/ASP3
 `aarch64-unknown-freebsd` | ✓ | ✓ | ARM64 FreeBSD
-`aarch64-unknown-hermit` | ? |  |
+`aarch64-unknown-hermit` | ✓ |  | ARM64 HermitCore
+[`aarch64-unknown-none-hermitkernel`](platform-support/aarch64-unknown-none-hermitkernel.md) | * |  | ARM64 HermitCore kernel
 `aarch64-unknown-uefi` | * |  | ARM64 UEFI
 `aarch64-unknown-linux-gnu_ilp32` | ✓ | ✓ | ARM64 Linux (ILP32 ABI)
 `aarch64-unknown-netbsd` | ✓ | ✓ |
@@ -286,10 +287,10 @@ target | std | host | notes
 `x86_64-sun-solaris` | ? |  | Deprecated target for 64-bit Solaris 10/11, illumos
 `x86_64-unknown-dragonfly` | ✓ | ✓ | 64-bit DragonFlyBSD
 `x86_64-unknown-haiku` | ✓ | ✓ | 64-bit Haiku
-`x86_64-unknown-hermit` | ? |  |
+`x86_64-unknown-hermit` | ✓ |  | HermitCore
 `x86_64-unknown-l4re-uclibc` | ? |  |
 [`x86_64-unknown-none`](platform-support/x86_64-unknown-none.md) | * |  | Freestanding/bare-metal x86_64, softfloat
-`x86_64-unknown-none-hermitkernel` | ? |  | HermitCore kernel
+`x86_64-unknown-none-hermitkernel` | * |  | HermitCore kernel
 `x86_64-unknown-none-linuxkernel` | * |  | Linux kernel modules
 [`x86_64-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 64-bit OpenBSD
 `x86_64-unknown-uefi` | * |  | 64-bit UEFI

src/doc/rustc/src/platform-support/aarch64-unknown-none-hermitkernel.md

@@ -0,0 +1,77 @@
+# `aarch64-unknown-none-hermitkernel`
+
+**Tier: 3**
+
+Required to build the kernel for [HermitCore](https://github.com/hermitcore/hermit-playground)
+or [RustyHermit](https://github.com/hermitcore/rusty-hermit).
+The result is a bare-metal aarch64 binary in ELF format.
+
+## Target maintainers
+
+- Stefan Lankes, https://github.com/stlankes
+
+## Requirements
+
+This target is cross-compiled. There is no support for `std`, but the
+library operating system provides a simple allocator to use `alloc`.
+
+By default, Rust code generated for this target does not use any vector or
+floating-point registers. This allows the generated code to build the library
+operaring system, which may need to avoid the use of such
+registers or which may have special considerations about the use of such
+registers (e.g. saving and restoring them to avoid breaking userspace code
+using the same registers). In contrast to `aarch64-unknown-none-softfloat`,
+the target is completly relocatable, which is a required feature of RustyHermit.
+
+By default, code generated with this target should run on any `aarch64`
+hardware; enabling additional target features may raise this baseline.
+On `aarch64-unknown-none-hermitkernel`, `extern "C"` uses the [standard System V calling
+convention](https://github.com/ARM-software/abi-aa/releases/download/2021Q3/sysvabi64.pdf),
+without red zones.
+
+This target generated binaries in the ELF format.
+
+## Building the target
+
+Typical you should not use the target directly. The target `aarch64-unknown-hermit`
+builds the _user space_ of RustyHermit and supports red zones and floating-point
+operations.
+To build and link the kernel to the application, the crate
+[hermit-sys](https://github.com/hermitcore/rusty-hermit/tree/master/hermit-sys)
+should be used by adding the following lines to the `Cargo.toml` file of
+your application.
+
+```toml
+[target.'cfg(target_os = "hermit")'.dependencies]
+hermit-sys = "0.1.*"
+```
+
+The crate `hermit-sys` uses the target `aarch64-unknown-none-hermitkernel`
+to build the kernel.
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for this target. To compile for
+this target, you need to build the crate `hermit-sys` (see
+"Building the target" above).
+
+## Testing
+
+As `aarch64-unknown-none-hermitkernel` does not support `std`
+and does not support running any Rust testsuite.
+
+## Cross-compilation toolchains and C code
+
+If you want to compile C code along with Rust you will need an
+appropriate `aarch64` toolchain.
+
+Rust *may* be able to use an `aarch64-linux-gnu-` toolchain with appropriate
+standalone flags to build for this toolchain (depending on the assumptions of
+that toolchain, see below), or you may wish to use a separate
+`aarch64-unknown-none` (or `aarch64-elf-`) toolchain.
+
+On some `aarch64` hosts that use ELF binaries, you *may* be able to use the host
+C toolchain, if it does not introduce assumptions about the host environment
+that don't match the expectations of a standalone environment. Otherwise, you
+may need a separate toolchain for standalone/freestanding development, just as
+when cross-compiling from a non-`aarch64` platform.

src/librustdoc/html/markdown.rs

@@ -565,7 +565,7 @@ impl<'a, 'b, 'ids, I: Iterator<Item = SpannedEvent<'a>>> Iterator
             self.buf.push_back((Event::Html(format!("</a></h{}>", level).into()), 0..0));
 
             let start_tags = format!(
-                "<h{level} id=\"{id}\" class=\"section-header\">\
+                "<h{level} id=\"{id}\">\
                     <a href=\"#{id}\">",
                 id = id,
                 level = level