Auto merge of #150028 - matthiaskrgr:rollup-6mq2ms9, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #148756 (Warn on codegen attributes on required trait methods)
 - #148790 (Add new Tier-3 target: riscv64im-unknown-none-elf)
 - #149271 (feat: dlopen Enzyme)
 - #149354 (Bootstrap config: libgccjit libs dir)
 - #149459 (std: sys: fs: uefi: Implement set_times and set_perm)
 - #149950 (Simplify how inline asm handles `MaybeUninit`)
 - #150000 (Port `#[rustc_legacy_const_generics]` to use attribute parser )
 - #150014 (Metadata loader cleanups)
 - #150021 (document that mpmc channels deliver an item to (at most) one receiver)

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

Author: bors

Cargo.lock

@@ -3613,6 +3613,7 @@ dependencies = [
  "gimli 0.31.1",
  "itertools",
  "libc",
+ "libloading 0.9.0",
  "measureme",
  "object 0.37.3",
  "rustc-demangle",

bootstrap.example.toml

@@ -191,6 +191,31 @@
 # Currently, this is only supported for the `x86_64-unknown-linux-gnu` target.
 #gcc.download-ci-gcc = false
 
+# Provide a directory of prebuilt libgccjit.so dylibs for given (host, target) compilation pairs.
+# This is useful when you want to cross-compile `rustc` to another target since GCC is not a
+# multi-target compiler.
+# You have to use a directory structure that looks like this:
+# `<libgccjit-libs-dir>/<host>/<target>/libgccjit.so`.
+# For example:
+#
+# ```
+# <libgccjit-libs-dir>
+# ├── m68k-unknown-linux-gnu
+# │   └── m68k-unknown-linux-gnu
+# │       └── libgccjit.so
+# └── x86_64-unknown-linux-gnu
+#     ├── m68k-unknown-linux-gnu
+#     │   └── libgccjit.so
+#     └── x86_64-unknown-linux-gnu
+#         └── libgccjit.so
+# ```
+# The directory above would allow you to cross-compile rustc from x64 to m68k
+#
+# Note that this option has priority over `gcc.download-ci-gcc`.
+# If you set both, bootstrap will first try to load libgccjit.so from this directory.
+# Only if it isn't found, it will try to download it from CI or build it locally.
+#gcc.libgccjit-libs-dir = "/path/to/libgccjit-libs-dir"
+
 # =============================================================================
 # General build configuration options
 # =============================================================================

compiler/rustc_ast_lowering/src/lib.rs

@@ -237,25 +237,27 @@ impl SpanLowerer {
 #[extension(trait ResolverAstLoweringExt)]
 impl ResolverAstLowering {
     fn legacy_const_generic_args(&self, expr: &Expr) -> Option<Vec<usize>> {
-        if let ExprKind::Path(None, path) = &expr.kind {
-            // Don't perform legacy const generics rewriting if the path already
-            // has generic arguments.
-            if path.segments.last().unwrap().args.is_some() {
-                return None;
-            }
+        let ExprKind::Path(None, path) = &expr.kind else {
+            return None;
+        };
 
-            if let Res::Def(DefKind::Fn, def_id) = self.partial_res_map.get(&expr.id)?.full_res()? {
-                // We only support cross-crate argument rewriting. Uses
-                // within the same crate should be updated to use the new
-                // const generics style.
-                if def_id.is_local() {
-                    return None;
-                }
+        // Don't perform legacy const generics rewriting if the path already
+        // has generic arguments.
+        if path.segments.last().unwrap().args.is_some() {
+            return None;
+        }
 
-                if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
-                    return v.clone();
-                }
-            }
+        let def_id = self.partial_res_map.get(&expr.id)?.full_res()?.opt_def_id()?;
+
+        // We only support cross-crate argument rewriting. Uses
+        // within the same crate should be updated to use the new
+        // const generics style.
+        if def_id.is_local() {
+            return None;
+        }
+
+        if let Some(v) = self.legacy_const_generic_args.get(&def_id) {
+            return v.clone();
         }
 
         None

compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs

@@ -61,7 +61,6 @@ impl<S: Stage> CombineAttributeParser<S> for AllowConstFnUnstableParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
     ]);

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -57,7 +57,6 @@ impl<S: Stage> NoArgsAttributeParser<S> for ColdParser {
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::ForeignFn),
         Allow(Target::Closure),
@@ -343,7 +342,7 @@ impl<S: Stage> NoArgsAttributeParser<S> for TrackCallerParser {
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
+        Allow(Target::Method(MethodKind::Trait { body: false })), // `#[track_caller]` is inherited from trait methods
         Allow(Target::ForeignFn),
         Allow(Target::Closure),
         Warn(Target::MacroDef),

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -469,7 +469,6 @@ impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
         Allow(Target::Static),
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
     ]);
@@ -587,12 +586,12 @@ impl<S: Stage> SingleAttributeParser<S> for LinkageParser {
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[
         Allow(Target::Fn),
         Allow(Target::Method(MethodKind::Inherent)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
         Allow(Target::Static),
         Allow(Target::ForeignStatic),
         Allow(Target::ForeignFn),
+        Warn(Target::Method(MethodKind::Trait { body: false })), // Not inherited
     ]);
 
     const TEMPLATE: AttributeTemplate = template!(NameValueStr: [

compiler/rustc_attr_parsing/src/attributes/repr.rs

@@ -315,7 +315,7 @@ impl<S: Stage> AttributeParser<S> for AlignParser {
         Allow(Target::Method(MethodKind::Inherent)),
         Allow(Target::Method(MethodKind::Trait { body: true })),
         Allow(Target::Method(MethodKind::TraitImpl)),
-        Allow(Target::Method(MethodKind::Trait { body: false })),
+        Allow(Target::Method(MethodKind::Trait { body: false })), // `#[align]` is inherited from trait methods
         Allow(Target::ForeignFn),
     ]);
 

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -1,3 +1,5 @@
+use rustc_ast::{LitIntType, LitKind, MetaItemLit};
+
 use super::prelude::*;
 use super::util::parse_single_integer;
 
@@ -76,3 +78,47 @@ impl<S: Stage> SingleAttributeParser<S> for RustcSimdMonomorphizeLaneLimitParser
         Some(AttributeKind::RustcSimdMonomorphizeLaneLimit(cx.parse_limit_int(nv)?))
     }
 }
+
+pub(crate) struct RustcLegacyConstGenericsParser;
+
+impl<S: Stage> SingleAttributeParser<S> for RustcLegacyConstGenericsParser {
+    const PATH: &[Symbol] = &[sym::rustc_legacy_const_generics];
+    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepInnermost;
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Fn)]);
+    const TEMPLATE: AttributeTemplate = template!(List: &["N"]);
+
+    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<AttributeKind> {
+        let ArgParser::List(meta_items) = args else {
+            cx.expected_list(cx.attr_span, args);
+            return None;
+        };
+
+        let mut parsed_indexes = ThinVec::new();
+        let mut errored = false;
+
+        for possible_index in meta_items.mixed() {
+            if let MetaItemOrLitParser::Lit(MetaItemLit {
+                kind: LitKind::Int(index, LitIntType::Unsuffixed),
+                ..
+            }) = possible_index
+            {
+                parsed_indexes.push((index.0 as usize, possible_index.span()));
+            } else {
+                cx.expected_integer_literal(possible_index.span());
+                errored = true;
+            }
+        }
+        if errored {
+            return None;
+        } else if parsed_indexes.is_empty() {
+            cx.expected_at_least_one_argument(args.span()?);
+            return None;
+        }
+
+        Some(AttributeKind::RustcLegacyConstGenerics {
+            fn_indexes: parsed_indexes,
+            attr_span: cx.attr_span,
+        })
+    }
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -59,8 +59,9 @@ use crate::attributes::proc_macro_attrs::{
 use crate::attributes::prototype::CustomMirParser;
 use crate::attributes::repr::{AlignParser, AlignStaticParser, ReprParser};
 use crate::attributes::rustc_internal::{
-    RustcLayoutScalarValidRangeEndParser, RustcLayoutScalarValidRangeStartParser, RustcMainParser,
-    RustcObjectLifetimeDefaultParser, RustcSimdMonomorphizeLaneLimitParser,
+    RustcLayoutScalarValidRangeEndParser, RustcLayoutScalarValidRangeStartParser,
+    RustcLegacyConstGenericsParser, RustcMainParser, RustcObjectLifetimeDefaultParser,
+    RustcSimdMonomorphizeLaneLimitParser,
 };
 use crate::attributes::semantics::MayDangleParser;
 use crate::attributes::stability::{
@@ -208,6 +209,7 @@ attribute_parsers!(
         Single<RustcForceInlineParser>,
         Single<RustcLayoutScalarValidRangeEndParser>,
         Single<RustcLayoutScalarValidRangeStartParser>,
+        Single<RustcLegacyConstGenericsParser>,
         Single<RustcObjectLifetimeDefaultParser>,
         Single<RustcSimdMonomorphizeLaneLimitParser>,
         Single<SanitizeParser>,

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -857,19 +857,9 @@ fn call_inline_asm<'tcx>(
 
 fn asm_clif_type<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> Option<types::Type> {
     match ty.kind() {
-        // Adapted from https://github.com/rust-lang/rust/blob/f3c66088610c1b80110297c2d9a8b5f9265b013f/compiler/rustc_hir_analysis/src/check/intrinsicck.rs#L136-L151
+        // Adapted from https://github.com/rust-lang/rust/blob/df44a57fd29fca899ce473f85ed64efd0708dd7c/compiler/rustc_hir_typeck/src/inline_asm.rs#L180-L183
         ty::Adt(adt, args) if fx.tcx.is_lang_item(adt.did(), LangItem::MaybeUninit) => {
-            let fields = &adt.non_enum_variant().fields;
-            let ty = fields[FieldIdx::ONE].ty(fx.tcx, args);
-            let ty::Adt(ty, args) = ty.kind() else {
-                unreachable!("expected first field of `MaybeUninit` to be an ADT")
-            };
-            assert!(
-                ty.is_manually_drop(),
-                "expected first field of `MaybeUninit` to be `ManuallyDrop`"
-            );
-            let fields = &ty.non_enum_variant().fields;
-            let ty = fields[FieldIdx::ZERO].ty(fx.tcx, args);
+            let ty = args.type_at(0);
             fx.clif_type(ty)
         }
         _ => fx.clif_type(ty),