Rollup of 10 pull requests

compiler/rustc_abi/src/layout/ty.rs

@@ -172,6 +172,8 @@ pub trait TyAbiInterface<'a, C>: Sized + std::fmt::Debug {
     fn is_tuple(this: TyAndLayout<'a, Self>) -> bool;
     fn is_unit(this: TyAndLayout<'a, Self>) -> bool;
     fn is_transparent(this: TyAndLayout<'a, Self>) -> bool;
+    /// See [`TyAndLayout::pass_indirectly_in_non_rustic_abis`] for details.
+    fn is_pass_indirectly_in_non_rustic_abis_flag_set(this: TyAndLayout<'a, Self>) -> bool;
 }
 
 impl<'a, Ty> TyAndLayout<'a, Ty> {
@@ -269,6 +271,30 @@ impl<'a, Ty> TyAndLayout<'a, Ty> {
         Ty::is_transparent(self)
     }
 
+    /// If this method returns `true`, then this type should always have a `PassMode` of
+    /// `Indirect { on_stack: false, .. }` when being used as the argument type of a function with a
+    /// non-Rustic ABI (this is true for structs annotated with the
+    /// `#[rustc_pass_indirectly_in_non_rustic_abis]` attribute).
+    ///
+    /// This is used to replicate some of the behaviour of C array-to-pointer decay; however unlike
+    /// C any changes the caller makes to the passed value will not be reflected in the callee, so
+    /// the attribute is only useful for types where observing the value in the caller after the
+    /// function call isn't allowed (a.k.a. `va_list`).
+    ///
+    /// This function handles transparent types automatically.
+    pub fn pass_indirectly_in_non_rustic_abis<C>(mut self, cx: &C) -> bool
+    where
+        Ty: TyAbiInterface<'a, C> + Copy,
+    {
+        while self.is_transparent()
+            && let Some((_, field)) = self.non_1zst_field(cx)
+        {
+            self = field;
+        }
+
+        Ty::is_pass_indirectly_in_non_rustic_abis_flag_set(self)
+    }
+
     /// Finds the one field that is not a 1-ZST.
     /// Returns `None` if there are multiple non-1-ZST fields or only 1-ZST-fields.
     pub fn non_1zst_field<C>(&self, cx: &C) -> Option<(FieldIdx, Self)>

compiler/rustc_abi/src/lib.rs

@@ -88,14 +88,17 @@ bitflags! {
         const IS_C               = 1 << 0;
         const IS_SIMD            = 1 << 1;
         const IS_TRANSPARENT     = 1 << 2;
-        // Internal only for now. If true, don't reorder fields.
-        // On its own it does not prevent ABI optimizations.
+        /// Internal only for now. If true, don't reorder fields.
+        /// On its own it does not prevent ABI optimizations.
         const IS_LINEAR          = 1 << 3;
-        // If true, the type's crate has opted into layout randomization.
-        // Other flags can still inhibit reordering and thus randomization.
-        // The seed stored in `ReprOptions.field_shuffle_seed`.
+        /// If true, the type's crate has opted into layout randomization.
+        /// Other flags can still inhibit reordering and thus randomization.
+        /// The seed stored in `ReprOptions.field_shuffle_seed`.
         const RANDOMIZE_LAYOUT   = 1 << 4;
-        // Any of these flags being set prevent field reordering optimisation.
+        /// If true, the type is always passed indirectly by non-Rustic ABIs.
+        /// See [`TyAndLayout::pass_indirectly_in_non_rustic_abis`] for details.
+        const PASS_INDIRECTLY_IN_NON_RUSTIC_ABIS = 1 << 5;
+        /// Any of these flags being set prevent field reordering optimisation.
         const FIELD_ORDER_UNOPTIMIZABLE   = ReprFlags::IS_C.bits()
                                  | ReprFlags::IS_SIMD.bits()
                                  | ReprFlags::IS_LINEAR.bits();

compiler/rustc_attr_parsing/src/attributes/codegen_attrs.rs

@@ -676,3 +676,12 @@ impl<S: Stage> SingleAttributeParser<S> for SanitizeParser {
         Some(AttributeKind::Sanitize { on_set, off_set, span: cx.attr_span })
     }
 }
+
+pub(crate) struct RustcPassIndirectlyInNonRusticAbisParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for RustcPassIndirectlyInNonRusticAbisParser {
+    const PATH: &[Symbol] = &[sym::rustc_pass_indirectly_in_non_rustic_abis];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Error;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Struct)]);
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::RustcPassIndirectlyInNonRusticAbis;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -20,8 +20,9 @@ use crate::attributes::allow_unstable::{
 use crate::attributes::body::CoroutineParser;
 use crate::attributes::codegen_attrs::{
     ColdParser, CoverageParser, ExportNameParser, ForceTargetFeatureParser, NakedParser,
-    NoMangleParser, ObjcClassParser, ObjcSelectorParser, OptimizeParser, SanitizeParser,
-    TargetFeatureParser, TrackCallerParser, UsedParser,
+    NoMangleParser, ObjcClassParser, ObjcSelectorParser, OptimizeParser,
+    RustcPassIndirectlyInNonRusticAbisParser, SanitizeParser, TargetFeatureParser,
+    TrackCallerParser, UsedParser,
 };
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::crate_level::{
@@ -241,6 +242,7 @@ attribute_parsers!(
         Single<WithoutArgs<PubTransparentParser>>,
         Single<WithoutArgs<RustcCoherenceIsCoreParser>>,
         Single<WithoutArgs<RustcMainParser>>,
+        Single<WithoutArgs<RustcPassIndirectlyInNonRusticAbisParser>>,
         Single<WithoutArgs<SpecializationTraitParser>>,
         Single<WithoutArgs<StdInternalSymbolParser>>,
         Single<WithoutArgs<TrackCallerParser>>,

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -150,8 +150,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     }
                 }
             }
-            PlaceRef { local: _, projection: [proj_base @ .., ProjectionElem::Deref] } => {
-                if the_place_err.local == ty::CAPTURE_STRUCT_LOCAL
+            PlaceRef { local, projection: [proj_base @ .., ProjectionElem::Deref] } => {
+                if local == ty::CAPTURE_STRUCT_LOCAL
                     && proj_base.is_empty()
                     && !self.upvars.is_empty()
                 {
@@ -165,10 +165,8 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         ", as `Fn` closures cannot mutate their captured variables".to_string()
                     }
                 } else {
-                    let source = self.borrowed_content_source(PlaceRef {
-                        local: the_place_err.local,
-                        projection: proj_base,
-                    });
+                    let source =
+                        self.borrowed_content_source(PlaceRef { local, projection: proj_base });
                     let pointer_type = source.describe_for_immutable_place(self.infcx.tcx);
                     opt_source = Some(source);
                     if let Some(desc) = self.describe_place(access_place.as_ref()) {
@@ -532,6 +530,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             PlaceRef { local, projection: [ProjectionElem::Deref] }
                 if local == ty::CAPTURE_STRUCT_LOCAL && !self.upvars.is_empty() =>
             {
+                self.point_at_binding_outside_closure(&mut err, local, access_place);
                 self.expected_fn_found_fn_mut_call(&mut err, span, act);
             }
 
@@ -950,6 +949,50 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         }
     }
 
+    /// When modifying a binding from inside of an `Fn` closure, point at the binding definition.
+    fn point_at_binding_outside_closure(
+        &self,
+        err: &mut Diag<'_>,
+        local: Local,
+        access_place: Place<'tcx>,
+    ) {
+        let place = access_place.as_ref();
+        for (index, elem) in place.projection.into_iter().enumerate() {
+            if let ProjectionElem::Deref = elem {
+                if index == 0 {
+                    if self.body.local_decls[local].is_ref_for_guard() {
+                        continue;
+                    }
+                    if let LocalInfo::StaticRef { .. } = *self.body.local_decls[local].local_info()
+                    {
+                        continue;
+                    }
+                }
+                if let Some(field) = self.is_upvar_field_projection(PlaceRef {
+                    local,
+                    projection: place.projection.split_at(index + 1).0,
+                }) {
+                    let var_index = field.index();
+                    let upvar = self.upvars[var_index];
+                    if let Some(hir_id) = upvar.info.capture_kind_expr_id {
+                        let node = self.infcx.tcx.hir_node(hir_id);
+                        if let hir::Node::Expr(expr) = node
+                            && let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind
+                            && let hir::def::Res::Local(hir_id) = path.res
+                            && let hir::Node::Pat(pat) = self.infcx.tcx.hir_node(hir_id)
+                        {
+                            let name = upvar.to_string(self.infcx.tcx);
+                            err.span_label(
+                                pat.span,
+                                format!("`{name}` declared here, outside the closure"),
+                            );
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+    }
     /// Targeted error when encountering an `FnMut` closure where an `Fn` closure was expected.
     fn expected_fn_found_fn_mut_call(&self, err: &mut Diag<'_>, sp: Span, act: &str) {
         err.span_label(sp, format!("cannot {act}"));
@@ -962,6 +1005,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let def_id = tcx.hir_enclosing_body_owner(fn_call_id);
         let mut look_at_return = true;
 
+        err.span_label(closure_span, "in this closure");
         // If the HIR node is a function or method call, get the DefId
         // of the callee function or method, the span, and args of the call expr
         let get_call_details = || {
@@ -1032,7 +1076,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             if let Some(span) = arg {
                 err.span_label(span, "change this to accept `FnMut` instead of `Fn`");
                 err.span_label(call_span, "expects `Fn` instead of `FnMut`");
-                err.span_label(closure_span, "in this closure");
                 look_at_return = false;
             }
         }
@@ -1059,7 +1102,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         sig.decl.output.span(),
                         "change this to return `FnMut` instead of `Fn`",
                     );
-                    err.span_label(closure_span, "in this closure");
                 }
                 _ => {}
             }

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -229,7 +229,7 @@ fn instrument_function_attr<'ll>(
 }
 
 fn nojumptables_attr<'ll>(cx: &SimpleCx<'ll>, sess: &Session) -> Option<&'ll Attribute> {
-    if !sess.opts.unstable_opts.no_jump_tables {
+    if sess.opts.cg.jump_tables {
         return None;
     }
 

compiler/rustc_feature/src/builtin_attrs.rs

@@ -657,6 +657,12 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         template!(Word, "https://doc.rust-lang.org/reference/attributes/codegen.html#the-naked-attribute"),
         WarnFollowing, EncodeCrossCrate::No
     ),
+    // See `TyAndLayout::pass_indirectly_in_non_rustic_abis` for details.
+    rustc_attr!(
+        rustc_pass_indirectly_in_non_rustic_abis, Normal, template!(Word), ErrorFollowing,
+        EncodeCrossCrate::No,
+        "types marked with `#[rustc_pass_indirectly_in_non_rustic_abis]` are always passed indirectly by non-Rustic abis."
+    ),
 
     // Limits:
     ungated!(

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -679,6 +679,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_object_lifetime_default]`.
     RustcObjectLifetimeDefault,
 
+    /// Represents `#[rustc_pass_indirectly_in_non_rustic_abis]`
+    RustcPassIndirectlyInNonRusticAbis(Span),
+
     /// Represents `#[rustc_simd_monomorphize_lane_limit = "N"]`.
     RustcSimdMonomorphizeLaneLimit(Limit),
 

compiler/rustc_hir/src/attrs/encode_cross_crate.rs

@@ -91,6 +91,7 @@ impl AttributeKind {
             RustcLayoutScalarValidRangeStart(..) => Yes,
             RustcMain => No,
             RustcObjectLifetimeDefault => No,
+            RustcPassIndirectlyInNonRusticAbis(..) => No,
             RustcSimdMonomorphizeLaneLimit(..) => Yes, // Affects layout computation, which needs to work cross-crate
             Sanitize { .. } => No,
             ShouldPanic { .. } => No,

compiler/rustc_hir/src/lib.rs

@@ -3,9 +3,9 @@
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(debug_closure_helpers))]
 #![feature(associated_type_defaults)]
 #![feature(closure_track_caller)]
-#![feature(debug_closure_helpers)]
 #![feature(exhaustive_patterns)]
 #![feature(never_type)]
 #![feature(variant_count)]

compiler/rustc_hir_analysis/src/lib.rs

@@ -59,10 +59,10 @@ This API is completely unstable and subject to change.
 #![allow(internal_features)]
 #![allow(rustc::diagnostic_outside_of_impl)]
 #![allow(rustc::untranslatable_diagnostic)]
+#![cfg_attr(bootstrap, feature(debug_closure_helpers))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
-#![feature(debug_closure_helpers)]
 #![feature(gen_blocks)]
 #![feature(if_let_guard)]
 #![feature(iter_intersperse)]

compiler/rustc_interface/src/tests.rs

@@ -620,6 +620,7 @@ fn test_codegen_options_tracking_hash() {
     tracked!(force_frame_pointers, FramePointer::Always);
     tracked!(force_unwind_tables, Some(true));
     tracked!(instrument_coverage, InstrumentCoverage::Yes);
+    tracked!(jump_tables, false);
     tracked!(link_dead_code, Some(true));
     tracked!(linker_plugin_lto, LinkerPluginLto::LinkerPluginAuto);
     tracked!(llvm_args, vec![String::from("1"), String::from("2")]);
@@ -831,7 +832,6 @@ fn test_unstable_options_tracking_hash() {
     tracked!(mutable_noalias, false);
     tracked!(next_solver, NextSolverConfig { coherence: true, globally: true });
     tracked!(no_generate_arange_section, true);
-    tracked!(no_jump_tables, true);
     tracked!(no_link, true);
     tracked!(no_profiler_runtime, true);
     tracked!(no_trait_vptr, true);

compiler/rustc_lint/src/builtin.rs

@@ -2875,6 +2875,71 @@ enum AsmLabelKind {
     Binary,
 }
 
+/// Checks if a potential label is actually a Hexagon register span notation.
+///
+/// Hexagon assembly uses register span notation like `r1:0`, `V5:4.w`, `p1:0` etc.
+/// These follow the pattern: `[letter][digit(s)]:[digit(s)][optional_suffix]`
+///
+/// Returns `true` if the string matches a valid Hexagon register span pattern.
+pub fn is_hexagon_register_span(possible_label: &str) -> bool {
+    // Extract the full register span from the context
+    if let Some(colon_idx) = possible_label.find(':') {
+        let after_colon = &possible_label[colon_idx + 1..];
+        is_hexagon_register_span_impl(&possible_label[..colon_idx], after_colon)
+    } else {
+        false
+    }
+}
+
+/// Helper function for use within the lint when we have statement context.
+fn is_hexagon_register_span_context(
+    possible_label: &str,
+    statement: &str,
+    colon_idx: usize,
+) -> bool {
+    // Extract what comes after the colon in the statement
+    let after_colon_start = colon_idx + 1;
+    if after_colon_start >= statement.len() {
+        return false;
+    }
+
+    // Get the part after the colon, up to the next whitespace or special character
+    let after_colon_full = &statement[after_colon_start..];
+    let after_colon = after_colon_full
+        .chars()
+        .take_while(|&c| c.is_ascii_alphanumeric() || c == '.')
+        .collect::<String>();
+
+    is_hexagon_register_span_impl(possible_label, &after_colon)
+}
+
+/// Core implementation for checking hexagon register spans.
+fn is_hexagon_register_span_impl(before_colon: &str, after_colon: &str) -> bool {
+    if before_colon.len() < 1 || after_colon.is_empty() {
+        return false;
+    }
+
+    let mut chars = before_colon.chars();
+    let start = chars.next().unwrap();
+
+    // Must start with a letter (r, V, p, etc.)
+    if !start.is_ascii_alphabetic() {
+        return false;
+    }
+
+    let rest = &before_colon[1..];
+
+    // Check if the part after the first letter is all digits and non-empty
+    if rest.is_empty() || !rest.chars().all(|c| c.is_ascii_digit()) {
+        return false;
+    }
+
+    // Check if after colon starts with digits (may have suffix like .w, .h)
+    let digits_after = after_colon.chars().take_while(|c| c.is_ascii_digit()).collect::<String>();
+
+    !digits_after.is_empty()
+}
+
 impl<'tcx> LateLintPass<'tcx> for AsmLabels {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
         if let hir::Expr {
@@ -2957,6 +3022,14 @@ impl<'tcx> LateLintPass<'tcx> for AsmLabels {
                             break 'label_loop;
                         }
 
+                        // Check for Hexagon register span notation (e.g., "r1:0", "V5:4", "V3:2.w")
+                        // This is valid Hexagon assembly syntax, not a label
+                        if matches!(cx.tcx.sess.asm_arch, Some(InlineAsmArch::Hexagon))
+                            && is_hexagon_register_span_context(possible_label, statement, idx)
+                        {
+                            break 'label_loop;
+                        }
+
                         for c in chars {
                             // Inside a template format arg, any character is permitted for the
                             // purposes of label detection because we assume that it can be