Auto merge of #120309 - fmease:rollup-kr7wqy6, r=fmease

Rollup of 9 pull requests

Successful merges:

 - #114764 ([style edition 2024] Combine all delimited exprs as last argument)
 - #118326 (Add `NonZero*::count_ones`)
 - #119460 (coverage: Never emit improperly-ordered coverage regions)
 - #119616 (Add a new `wasm32-wasi-preview2` target)
 - #120185 (coverage: Don't instrument `#[automatically_derived]` functions)
 - #120265 (Remove no-system-llvm)
 - #120284 (privacy: Refactor top-level visiting in `TypePrivacyVisitor`)
 - #120285 (Remove extra # from url in suggestion)
 - #120299 (Add mw to review rotation and add some owner assignments)

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

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -329,7 +329,7 @@ fn make_code_region(
     start_line = source_map.doctest_offset_line(&file.name, start_line);
     end_line = source_map.doctest_offset_line(&file.name, end_line);
 
-    Some(CodeRegion {
+    check_code_region(CodeRegion {
         file_name,
         start_line: start_line as u32,
         start_col: start_col as u32,
@@ -338,6 +338,39 @@ fn make_code_region(
     })
 }
 
+/// If `llvm-cov` sees a code region that is improperly ordered (end < start),
+/// it will immediately exit with a fatal error. To prevent that from happening,
+/// discard regions that are improperly ordered, or might be interpreted in a
+/// way that makes them improperly ordered.
+fn check_code_region(code_region: CodeRegion) -> Option<CodeRegion> {
+    let CodeRegion { file_name: _, start_line, start_col, end_line, end_col } = code_region;
+
+    // Line/column coordinates are supposed to be 1-based. If we ever emit
+    // coordinates of 0, `llvm-cov` might misinterpret them.
+    let all_nonzero = [start_line, start_col, end_line, end_col].into_iter().all(|x| x != 0);
+    // Coverage mappings use the high bit of `end_col` to indicate that a
+    // region is actually a "gap" region, so make sure it's unset.
+    let end_col_has_high_bit_unset = (end_col & (1 << 31)) == 0;
+    // If a region is improperly ordered (end < start), `llvm-cov` will exit
+    // with a fatal error, which is inconvenient for users and hard to debug.
+    let is_ordered = (start_line, start_col) <= (end_line, end_col);
+
+    if all_nonzero && end_col_has_high_bit_unset && is_ordered {
+        Some(code_region)
+    } else {
+        debug!(
+            ?code_region,
+            ?all_nonzero,
+            ?end_col_has_high_bit_unset,
+            ?is_ordered,
+            "Skipping code region that would be misinterpreted or rejected by LLVM"
+        );
+        // If this happens in a debug build, ICE to make it easier to notice.
+        debug_assert!(false, "Improper code region: {code_region:?}");
+        None
+    }
+}
+
 fn is_eligible_for_coverage(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
     // Only instrument functions, methods, and closures (not constants since they are evaluated
     // at compile time by Miri).
@@ -351,7 +384,18 @@ fn is_eligible_for_coverage(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
         return false;
     }
 
+    // Don't instrument functions with `#[automatically_derived]` on their
+    // enclosing impl block, on the assumption that most users won't care about
+    // coverage for derived impls.
+    if let Some(impl_of) = tcx.impl_of_method(def_id.to_def_id())
+        && tcx.is_automatically_derived(impl_of)
+    {
+        trace!("InstrumentCoverage skipped for {def_id:?} (automatically derived)");
+        return false;
+    }
+
     if tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::NO_COVERAGE) {
+        trace!("InstrumentCoverage skipped for {def_id:?} (`#[coverage(off)]`)");
         return false;
     }
 

compiler/rustc_privacy/src/lib.rs

@@ -24,13 +24,13 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId, CRATE_DEF_ID};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{AssocItemKind, ForeignItemKind, ItemId, PatKind};
-use rustc_middle::bug;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::privacy::{EffectiveVisibilities, EffectiveVisibility, Level};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::GenericArgs;
 use rustc_middle::ty::{self, Const, GenericParamDefKind};
 use rustc_middle::ty::{TraitRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor};
+use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
 use rustc_span::hygiene::Transparency;
 use rustc_span::symbol::{kw, sym, Ident};
@@ -1064,29 +1064,22 @@ impl<'tcx> Visitor<'tcx> for NamePrivacyVisitor<'tcx> {
 
 struct TypePrivacyVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
+    module_def_id: LocalModDefId,
     maybe_typeck_results: Option<&'tcx ty::TypeckResults<'tcx>>,
-    current_item: LocalDefId,
     span: Span,
 }
 
 impl<'tcx> TypePrivacyVisitor<'tcx> {
-    /// Gets the type-checking results for the current body.
-    /// As this will ICE if called outside bodies, only call when working with
-    /// `Expr` or `Pat` nodes (they are guaranteed to be found only in bodies).
-    #[track_caller]
-    fn typeck_results(&self) -> &'tcx ty::TypeckResults<'tcx> {
-        self.maybe_typeck_results
-            .expect("`TypePrivacyVisitor::typeck_results` called outside of body")
-    }
-
     fn item_is_accessible(&self, did: DefId) -> bool {
-        self.tcx.visibility(did).is_accessible_from(self.current_item, self.tcx)
+        self.tcx.visibility(did).is_accessible_from(self.module_def_id, self.tcx)
     }
 
     // Take node-id of an expression or pattern and check its type for privacy.
     fn check_expr_pat_type(&mut self, id: hir::HirId, span: Span) -> bool {
         self.span = span;
-        let typeck_results = self.typeck_results();
+        let typeck_results = self
+            .maybe_typeck_results
+            .unwrap_or_else(|| span_bug!(span, "`hir::Expr` or `hir::Pat` outside of a body"));
         let result: ControlFlow<()> = try {
             self.visit(typeck_results.node_type(id))?;
             self.visit(typeck_results.node_args(id))?;
@@ -1107,35 +1100,13 @@ impl<'tcx> TypePrivacyVisitor<'tcx> {
 }
 
 impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
-    type NestedFilter = nested_filter::All;
-
-    /// We want to visit items in the context of their containing
-    /// module and so forth, so supply a crate for doing a deep walk.
-    fn nested_visit_map(&mut self) -> Self::Map {
-        self.tcx.hir()
-    }
-
-    fn visit_mod(&mut self, _m: &'tcx hir::Mod<'tcx>, _s: Span, _n: hir::HirId) {
-        // Don't visit nested modules, since we run a separate visitor walk
-        // for each module in `effective_visibilities`
-    }
-
-    fn visit_nested_body(&mut self, body: hir::BodyId) {
+    fn visit_nested_body(&mut self, body_id: hir::BodyId) {
         let old_maybe_typeck_results =
-            self.maybe_typeck_results.replace(self.tcx.typeck_body(body));
-        let body = self.tcx.hir().body(body);
-        self.visit_body(body);
+            self.maybe_typeck_results.replace(self.tcx.typeck_body(body_id));
+        self.visit_body(self.tcx.hir().body(body_id));
         self.maybe_typeck_results = old_maybe_typeck_results;
     }
 
-    fn visit_generic_arg(&mut self, generic_arg: &'tcx hir::GenericArg<'tcx>) {
-        match generic_arg {
-            hir::GenericArg::Type(t) => self.visit_ty(t),
-            hir::GenericArg::Infer(inf) => self.visit_infer(inf),
-            hir::GenericArg::Lifetime(_) | hir::GenericArg::Const(_) => {}
-        }
-    }
-
     fn visit_ty(&mut self, hir_ty: &'tcx hir::Ty<'tcx>) {
         self.span = hir_ty.span;
         if let Some(typeck_results) = self.maybe_typeck_results {
@@ -1163,19 +1134,19 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
                     return;
                 }
             } else {
-                // We don't do anything for const infers here.
+                // FIXME: check types of const infers here.
             }
         } else {
-            bug!("visit_infer without typeck_results");
+            span_bug!(self.span, "`hir::InferArg` outside of a body");
         }
         intravisit::walk_inf(self, inf);
     }
 
     fn visit_trait_ref(&mut self, trait_ref: &'tcx hir::TraitRef<'tcx>) {
         self.span = trait_ref.path.span;
-        if self.maybe_typeck_results.is_none() {
-            // Avoid calling `hir_trait_to_predicates` in bodies, it will ICE.
-            // The traits' privacy in bodies is already checked as a part of trait object types.
+        if self.maybe_typeck_results.is_some() {
+            // Privacy of traits in bodies is checked as a part of trait object types.
+        } else {
             let bounds = rustc_hir_analysis::hir_trait_to_predicates(
                 self.tcx,
                 trait_ref,
@@ -1223,7 +1194,10 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
             hir::ExprKind::MethodCall(segment, ..) => {
                 // Method calls have to be checked specially.
                 self.span = segment.ident.span;
-                if let Some(def_id) = self.typeck_results().type_dependent_def_id(expr.hir_id) {
+                let typeck_results = self
+                    .maybe_typeck_results
+                    .unwrap_or_else(|| span_bug!(self.span, "`hir::Expr` outside of a body"));
+                if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
                     if self.visit(self.tcx.type_of(def_id).instantiate_identity()).is_break() {
                         return;
                     }
@@ -1251,9 +1225,13 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
                 Res::Def(kind, def_id) => Some((kind, def_id)),
                 _ => None,
             },
-            hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => self
-                .maybe_typeck_results
-                .and_then(|typeck_results| typeck_results.type_dependent_def(id)),
+            hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => {
+                match self.maybe_typeck_results {
+                    Some(typeck_results) => typeck_results.type_dependent_def(id),
+                    // FIXME: Check type-relative associated types in signatures.
+                    None => None,
+                }
+            }
         };
         let def = def.filter(|(kind, _)| {
             matches!(
@@ -1307,15 +1285,6 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
 
         intravisit::walk_local(self, local);
     }
-
-    // Check types in item interfaces.
-    fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
-        let orig_current_item = mem::replace(&mut self.current_item, item.owner_id.def_id);
-        let old_maybe_typeck_results = self.maybe_typeck_results.take();
-        intravisit::walk_item(self, item);
-        self.maybe_typeck_results = old_maybe_typeck_results;
-        self.current_item = orig_current_item;
-    }
 }
 
 impl<'tcx> DefIdVisitor<'tcx> for TypePrivacyVisitor<'tcx> {
@@ -1785,13 +1754,8 @@ fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
 
     // Check privacy of explicitly written types and traits as well as
     // inferred types of expressions and patterns.
-    let mut visitor = TypePrivacyVisitor {
-        tcx,
-        maybe_typeck_results: None,
-        current_item: module_def_id.to_local_def_id(),
-        span,
-    };
-    intravisit::walk_mod(&mut visitor, module, hir_id);
+    let mut visitor = TypePrivacyVisitor { tcx, module_def_id, maybe_typeck_results: None, span };
+    tcx.hir().visit_item_likes_in_module(module_def_id, &mut visitor);
 }
 
 fn effective_visibilities(tcx: TyCtxt<'_>, (): ()) -> &EffectiveVisibilities {

compiler/rustc_span/src/symbol.rs

@@ -1793,6 +1793,7 @@ symbols! {
         warn,
         wasm_abi,
         wasm_import_module,
+        wasm_preview2,
         wasm_target_feature,
         while_let,
         windows,

compiler/rustc_target/src/spec/mod.rs

@@ -1574,6 +1574,7 @@ supported_targets! {
     ("wasm32-unknown-emscripten", wasm32_unknown_emscripten),
     ("wasm32-unknown-unknown", wasm32_unknown_unknown),
     ("wasm32-wasi", wasm32_wasi),
+    ("wasm32-wasi-preview2", wasm32_wasi_preview2),
     ("wasm32-wasi-preview1-threads", wasm32_wasi_preview1_threads),
     ("wasm64-unknown-unknown", wasm64_unknown_unknown),
 

compiler/rustc_target/src/spec/targets/wasm32_wasi_preview1_threads.rs

@@ -72,11 +72,12 @@
 //! best we can with this target. Don't start relying on too much here unless
 //! you know what you're getting in to!
 
-use crate::spec::{base, crt_objects, Cc, LinkSelfContainedDefault, LinkerFlavor, Target};
+use crate::spec::{base, crt_objects, cvs, Cc, LinkSelfContainedDefault, LinkerFlavor, Target};
 
 pub fn target() -> Target {
     let mut options = base::wasm::options();
 
+    options.families = cvs!["wasm", "wasi"];
     options.os = "wasi".into();
 
     options.add_pre_link_args(

compiler/rustc_target/src/spec/targets/wasm32_wasi_preview2.rs

@@ -0,0 +1,64 @@
+//! The `wasm32-wasi-preview2` target is the next evolution of the
+//! wasm32-wasi target. While the wasi specification is still under
+//! active development, the {review 2 iteration is considered an "island
+//! of stability" that should allow users to rely on it indefinitely.
+//!
+//! The `wasi` target is a proposal to define a standardized set of WebAssembly
+//! component imports that allow it to interoperate with the host system in a
+//! standardized way. This set of imports is intended to empower WebAssembly
+//! binaries with host capabilities such as filesystem access, network access, etc.
+//!
+//! Wasi Preview 2 relies on the WebAssembly component model which is an extension of
+//! the core WebAssembly specification which allows interoperability between WebAssembly
+//! modules (known as "components") through high-level, shared-nothing APIs instead of the
+//! low-level, shared-everything linear memory model of the core WebAssembly specification.
+//!
+//! You can see more about wasi at <https://wasi.dev> and the component model at
+//! <https://github.com/WebAssembly/component-model>.
+
+use crate::spec::crt_objects;
+use crate::spec::LinkSelfContainedDefault;
+use crate::spec::{base, Target};
+
+pub fn target() -> Target {
+    let mut options = base::wasm::options();
+
+    options.os = "wasi".into();
+    options.env = "preview2".into();
+    options.linker = Some("wasm-component-ld".into());
+
+    options.pre_link_objects_self_contained = crt_objects::pre_wasi_self_contained();
+    options.post_link_objects_self_contained = crt_objects::post_wasi_self_contained();
+
+    // FIXME: Figure out cases in which WASM needs to link with a native toolchain.
+    options.link_self_contained = LinkSelfContainedDefault::True;
+
+    // Right now this is a bit of a workaround but we're currently saying that
+    // the target by default has a static crt which we're taking as a signal
+    // for "use the bundled crt". If that's turned off then the system's crt
+    // will be used, but this means that default usage of this target doesn't
+    // need an external compiler but it's still interoperable with an external
+    // compiler if configured correctly.
+    options.crt_static_default = true;
+    options.crt_static_respected = true;
+
+    // Allow `+crt-static` to create a "cdylib" output which is just a wasm file
+    // without a main function.
+    options.crt_static_allows_dylibs = true;
+
+    // WASI's `sys::args::init` function ignores its arguments; instead,
+    // `args::args()` makes the WASI API calls itself.
+    options.main_needs_argc_argv = false;
+
+    // And, WASI mangles the name of "main" to distinguish between different
+    // signatures.
+    options.entry_name = "__main_void".into();
+
+    Target {
+        llvm_target: "wasm32-unknown-unknown".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20".into(),
+        arch: "wasm32".into(),
+        options,
+    }
+}

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -3155,7 +3155,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 } else {
                     // FIXME: we may suggest array::repeat instead
                     err.help("consider using `core::array::from_fn` to initialize the array");
-                    err.help("see https://doc.rust-lang.org/stable/std/array/fn.from_fn.html# for more information");
+                    err.help("see https://doc.rust-lang.org/stable/std/array/fn.from_fn.html for more information");
                 }
 
                 if self.tcx.sess.is_nightly_build()

library/core/src/num/nonzero.rs

@@ -288,6 +288,43 @@ macro_rules! nonzero_integer {
                 unsafe { intrinsics::cttz_nonzero(self.get() as $UnsignedPrimitive) as u32 }
             }
 
+            /// Returns the number of ones in the binary representation of `self`.
+            ///
+            /// # Examples
+            ///
+            /// Basic usage:
+            ///
+            /// ```
+            /// #![feature(non_zero_count_ones)]
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("# use std::num::{self, ", stringify!($Ty), "};")]
+            ///
+            /// let one = num::NonZeroU32::new(1)?;
+            /// let three = num::NonZeroU32::new(3)?;
+            #[doc = concat!("let a = ", stringify!($Ty), "::new(0b100_0000)?;")]
+            #[doc = concat!("let b = ", stringify!($Ty), "::new(0b100_0011)?;")]
+            ///
+            /// assert_eq!(a.count_ones(), one);
+            /// assert_eq!(b.count_ones(), three);
+            /// # Some(())
+            /// # }
+            /// ```
+            ///
+            #[unstable(feature = "non_zero_count_ones", issue = "120287")]
+            #[rustc_const_unstable(feature = "non_zero_count_ones", issue = "120287")]
+            #[doc(alias = "popcount")]
+            #[doc(alias = "popcnt")]
+            #[must_use = "this returns the result of the operation, \
+                        without modifying the original"]
+            #[inline(always)]
+            pub const fn count_ones(self) -> NonZeroU32 {
+                // SAFETY:
+                // `self` is non-zero, which means it has at least one bit set, which means
+                // that the result of `count_ones` is non-zero.
+                unsafe { NonZeroU32::new_unchecked(self.get().count_ones()) }
+            }
+
             nonzero_integer_signedness_dependent_methods! {
                 Self = $Ty,
                 Primitive = $signedness $Int,