Merge pull request #21143 from rust-lang/rustc-pull

minor: sync from downstream

Author: lnicola

Cargo.lock

@@ -708,6 +708,12 @@
 # desired in distributions, for example.
 #rust.rpath = true
 
+# Additional flags to pass to `rustc`.
+# Takes precedence over bootstrap's own flags but not over per target rustflags nor env. vars. like RUSTFLAGS.
+# Applies to all stages and targets.
+#
+#rust.rustflags = []
+
 # Indicates whether symbols should be stripped using `-Cstrip=symbols`.
 #rust.strip = false
 
@@ -1013,6 +1019,12 @@
 # and will override the same option under [rust] section. It only works on Unix platforms
 #rpath = rust.rpath (bool)
 
+# Additional flags to pass to `rustc`.
+# Takes precedence over bootstrap's own flags and `rust.rustflags` but not over env. vars. like RUSTFLAGS.
+# Applies to all stages.
+#
+#rustflags = rust.rustflags
+
 # Force static or dynamic linkage of the standard library for this target. If
 # this target is a host for rustc, this will also affect the linkage of the
 # compiler itself. This is useful for building rustc on targets that normally

bootstrap.example.toml

@@ -20,17 +20,25 @@ rustc_public = { path = "../rustc_public" }
 rustc_public_bridge = { path = "../rustc_public_bridge" }
 # tidy-alphabetical-end
 
+# Pin these to avoid pulling in a package with a binary blob
+# <https://github.com/rust-lang/rust/pull/136395#issuecomment-2692769062>
+[target.'cfg(target_os = "wasi")'.dependencies]
+getrandom = "=0.3.3"
+wasi = "=0.14.2"
+
+
 [dependencies.tikv-jemalloc-sys]
-version = "0.6.0"
+version = "0.6.1"
 optional = true
-features = ['unprefixed_malloc_on_supported_platforms']
+features = ['override_allocator_on_supported_platforms']
 
 [features]
 # tidy-alphabetical-start
 check_only = ['rustc_driver_impl/check_only']
 jemalloc = ['dep:tikv-jemalloc-sys']
 llvm = ['rustc_driver_impl/llvm']
 llvm_enzyme = ['rustc_driver_impl/llvm_enzyme']
+llvm_offload = ['rustc_driver_impl/llvm_offload']
 max_level_info = ['rustc_driver_impl/max_level_info']
 rustc_randomized_layouts = ['rustc_driver_impl/rustc_randomized_layouts']
 # tidy-alphabetical-end

compiler/rustc/Cargo.toml

@@ -7,26 +7,25 @@
 // distribution. The obvious way to do this is with the `#[global_allocator]`
 // mechanism. However, for complicated reasons (see
 // https://github.com/rust-lang/rust/pull/81782#issuecomment-784438001 for some
-// details) that mechanism doesn't work here. Also, we must use a consistent
-// allocator across the rustc <-> llvm boundary, and `#[global_allocator]`
-// wouldn't provide that.
+// details) that mechanism doesn't work here. Also, we'd like to use a
+// consistent allocator across the rustc <-> llvm boundary, and
+// `#[global_allocator]` wouldn't provide that.
 //
-// Instead, we use a lower-level mechanism. rustc is linked with jemalloc in a
-// way such that jemalloc's implementation of `malloc`, `free`, etc., override
-// the libc allocator's implementation. This means that Rust's `System`
-// allocator, which calls `libc::malloc()` et al., is actually calling into
-// jemalloc.
+// Instead, we use a lower-level mechanism, namely the
+// `"override_allocator_on_supported_platforms"` Cargo feature of jemalloc-sys.
+//
+// This makes jemalloc-sys override the libc/system allocator's implementation
+// of `malloc`, `free`, etc.. This means that Rust's `System` allocator, which
+// calls `libc::malloc()` et al., is actually calling into jemalloc.
 //
 // A consequence of not using `GlobalAlloc` (and the `tikv-jemallocator` crate
 // provides an impl of that trait, which is called `Jemalloc`) is that we
 // cannot use the sized deallocation APIs (`sdallocx`) that jemalloc provides.
 // It's unclear how much performance is lost because of this.
 //
-// As for the symbol overrides in `main` below: we're pulling in a static copy
-// of jemalloc. We need to actually reference its symbols for it to get linked.
-// The two crates we link to here, `std` and `rustc_driver`, are both dynamic
-// libraries. So we must reference jemalloc symbols one way or another, because
-// this file is the only object code in the rustc executable.
+// NOTE: Even though Cargo passes `--extern` with `tikv_jemalloc_sys`, we still need to `use` the
+// crate for the compiler to see the `#[used]`, see https://github.com/rust-lang/rust/issues/64402.
+// This is similarly required if we used a crate with `#[global_allocator]`.
 //
 // NOTE: if you are reading this comment because you want to set a custom `global_allocator` for
 // benchmarking, consider using the benchmarks in the `rustc-perf` collector suite instead:
@@ -36,43 +35,9 @@
 // to compare their performance, see
 // https://github.com/rust-lang/rust/commit/b90cfc887c31c3e7a9e6d462e2464db1fe506175#diff-43914724af6e464c1da2171e4a9b6c7e607d5bc1203fa95c0ab85be4122605ef
 // for an example of how to do so.
+#[cfg(feature = "jemalloc")]
+use tikv_jemalloc_sys as _;
 
 fn main() {
-    // See the comment at the top of this file for an explanation of this.
-    #[cfg(feature = "jemalloc")]
-    {
-        use std::os::raw::{c_int, c_void};
-
-        use tikv_jemalloc_sys as jemalloc_sys;
-
-        #[used]
-        static _F1: unsafe extern "C" fn(usize, usize) -> *mut c_void = jemalloc_sys::calloc;
-        #[used]
-        static _F2: unsafe extern "C" fn(*mut *mut c_void, usize, usize) -> c_int =
-            jemalloc_sys::posix_memalign;
-        #[used]
-        static _F3: unsafe extern "C" fn(usize, usize) -> *mut c_void = jemalloc_sys::aligned_alloc;
-        #[used]
-        static _F4: unsafe extern "C" fn(usize) -> *mut c_void = jemalloc_sys::malloc;
-        #[used]
-        static _F5: unsafe extern "C" fn(*mut c_void, usize) -> *mut c_void = jemalloc_sys::realloc;
-        #[used]
-        static _F6: unsafe extern "C" fn(*mut c_void) = jemalloc_sys::free;
-
-        // On OSX, jemalloc doesn't directly override malloc/free, but instead
-        // registers itself with the allocator's zone APIs in a ctor. However,
-        // the linker doesn't seem to consider ctors as "used" when statically
-        // linking, so we need to explicitly depend on the function.
-        #[cfg(target_os = "macos")]
-        {
-            unsafe extern "C" {
-                fn _rjem_je_zone_register();
-            }
-
-            #[used]
-            static _F7: unsafe extern "C" fn() = _rjem_je_zone_register;
-        }
-    }
-
     rustc_driver::main()
 }

compiler/rustc/src/main.rs

@@ -857,15 +857,15 @@ impl BindingMode {
     }
 }
 
-#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
+#[derive(Clone, Copy, Encodable, Decodable, Debug, Walkable)]
 pub enum RangeEnd {
     /// `..=` or `...`
     Included(RangeSyntax),
     /// `..`
     Excluded,
 }
 
-#[derive(Clone, Encodable, Decodable, Debug, Walkable)]
+#[derive(Clone, Copy, Encodable, Decodable, Debug, Walkable)]
 pub enum RangeSyntax {
     /// `...`
     DotDotDot,
@@ -1915,7 +1915,7 @@ pub enum ForLoopKind {
 }
 
 /// Used to differentiate between `async {}` blocks and `gen {}` blocks.
-#[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq, Walkable)]
+#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq, Eq, Walkable)]
 pub enum GenBlockKind {
     Async,
     Gen,

compiler/rustc_ast/src/ast.rs

@@ -37,9 +37,10 @@ ast_passes_assoc_type_without_body =
     .suggestion = provide a definition for the type
 
 ast_passes_async_fn_in_const_trait_or_trait_impl =
-    async functions are not allowed in `const` {$in_impl ->
-        [true] trait impls
-        *[false] traits
+    async functions are not allowed in `const` {$context ->
+        [trait_impl] trait impls
+        [impl] impls
+        *[trait] traits
     }
     .label = associated functions of `const` cannot be declared `async`
 
@@ -88,6 +89,9 @@ ast_passes_const_and_coroutine = functions cannot be both `const` and `{$corouti
     .coroutine = `{$coroutine_kind}` because of this
     .label = {""}
 
+ast_passes_const_auto_trait = auto traits cannot be const
+    .help = remove the `const` keyword
+
 ast_passes_const_bound_trait_object = const trait bounds are not allowed in trait object types
 
 ast_passes_const_without_body =

compiler/rustc_ast_passes/messages.ftl

@@ -312,9 +312,15 @@ impl<'a> AstValidator<'a> {
             return;
         };
 
+        let context = match parent {
+            TraitOrImpl::Trait { .. } => "trait",
+            TraitOrImpl::TraitImpl { .. } => "trait_impl",
+            TraitOrImpl::Impl { .. } => "impl",
+        };
+
         self.dcx().emit_err(errors::AsyncFnInConstTraitOrTraitImpl {
             async_keyword,
-            in_impl: matches!(parent, TraitOrImpl::TraitImpl { .. }),
+            context,
             const_keyword,
         });
     }
@@ -814,6 +820,12 @@ impl<'a> AstValidator<'a> {
         self.dcx().emit_err(errors::ModuleNonAscii { span: ident.span, name: ident.name });
     }
 
+    fn deny_const_auto_traits(&self, constness: Const) {
+        if let Const::Yes(span) = constness {
+            self.dcx().emit_err(errors::ConstAutoTrait { span });
+        }
+    }
+
     fn deny_generic_params(&self, generics: &Generics, ident_span: Span) {
         if !generics.params.is_empty() {
             self.dcx()
@@ -1251,6 +1263,8 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             }) => {
                 self.visit_attrs_vis_ident(&item.attrs, &item.vis, ident);
                 if *is_auto == IsAuto::Yes {
+                    // For why we reject `const auto trait`, see rust-lang/rust#149285.
+                    self.deny_const_auto_traits(*constness);
                     // Auto traits cannot have generics, super traits nor contain items.
                     self.deny_generic_params(generics, ident.span);
                     self.deny_super_traits(bounds, ident.span);
@@ -1714,9 +1728,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     self.check_async_fn_in_const_trait_or_impl(sig, parent);
                 }
             }
-            Some(TraitOrImpl::Impl { constness }) => {
+            Some(parent @ TraitOrImpl::Impl { constness }) => {
                 if let AssocItemKind::Fn(box Fn { sig, .. }) = &item.kind {
                     self.check_impl_fn_not_const(sig.header.constness, *constness);
+                    self.check_async_fn_in_const_trait_or_impl(sig, parent);
                 }
             }
             None => {}

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -76,7 +76,7 @@ pub(crate) struct TraitFnConst {
 pub(crate) struct AsyncFnInConstTraitOrTraitImpl {
     #[primary_span]
     pub async_keyword: Span,
-    pub in_impl: bool,
+    pub context: &'static str,
     #[label]
     pub const_keyword: Span,
 }
@@ -429,6 +429,14 @@ pub(crate) struct AutoTraitItems {
     pub ident: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(ast_passes_const_auto_trait)]
+#[help]
+pub(crate) struct ConstAutoTrait {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(ast_passes_generic_before_constraints)]
 pub(crate) struct ArgsBeforeConstraint {

compiler/rustc_ast_passes/src/errors.rs

@@ -82,7 +82,8 @@ pub fn parse_cfg_entry<S: Stage>(
                 }
             },
             a @ (ArgParser::NoArgs | ArgParser::NameValue(_)) => {
-                let Some(name) = meta.path().word_sym() else {
+                let Some(name) = meta.path().word_sym().filter(|s| !s.is_path_segment_keyword())
+                else {
                     return Err(cx.expected_identifier(meta.path().span()));
                 };
                 parse_name_value(name, meta.path().span(), a.name_value(), meta.span(), cx)?
@@ -158,7 +159,7 @@ fn parse_cfg_entry_target<S: Stage>(
         };
 
         // Then, parse it as a name-value item
-        let Some(name) = sub_item.path().word_sym() else {
+        let Some(name) = sub_item.path().word_sym().filter(|s| !s.is_path_segment_keyword()) else {
             return Err(cx.expected_identifier(sub_item.path().span()));
         };
         let name = Symbol::intern(&format!("target_{name}"));

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -220,7 +220,10 @@ pub fn eval_condition(
                 }
             }
         }
-        MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
+        MetaItemKind::Word | MetaItemKind::NameValue(..)
+            if cfg.path.segments.len() != 1
+                || cfg.path.segments[0].ident.is_path_segment_keyword() =>
+        {
             dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span });
             true
         }