Auto merge of rust-lang#117272 - matthiaskrgr:rollup-upg122z, r=matth…

…iaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#114998 (feat(docs): add cargo-pgo to PGO documentation 📝)
 - rust-lang#116868 (Tweak suggestion span for outer attr and point at item following invalid inner attr)
 - rust-lang#117240 (Fix documentation typo in std::iter::Iterator::collect_into)
 - rust-lang#117241 (Stash and cancel cycle errors for auto trait leakage in opaques)
 - rust-lang#117262 (Create a new ConstantKind variant (ZeroSized) for StableMIR)
 - rust-lang#117266 (replace transmute by raw pointer cast)

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

compiler/rustc_errors/src/lib.rs

@@ -508,6 +508,8 @@ pub enum StashKey {
     TraitMissingMethod,
     OpaqueHiddenTypeMismatch,
     MaybeForgetReturn,
+    /// Query cycle detected, stashing in favor of a better error.
+    Cycle,
 }
 
 fn default_track_diagnostic(d: &mut Diagnostic, f: &mut dyn FnMut(&mut Diagnostic)) {

compiler/rustc_macros/src/query.rs

@@ -97,6 +97,9 @@ struct QueryModifiers {
     /// A cycle error results in a delay_bug call
     cycle_delay_bug: Option<Ident>,
 
+    /// A cycle error results in a stashed cycle error that can be unstashed and canceled later
+    cycle_stash: Option<Ident>,
+
     /// Don't hash the result, instead just mark a query red if it runs
     no_hash: Option<Ident>,
 
@@ -127,6 +130,7 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
     let mut desc = None;
     let mut fatal_cycle = None;
     let mut cycle_delay_bug = None;
+    let mut cycle_stash = None;
     let mut no_hash = None;
     let mut anon = None;
     let mut eval_always = None;
@@ -181,6 +185,8 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
             try_insert!(fatal_cycle = modifier);
         } else if modifier == "cycle_delay_bug" {
             try_insert!(cycle_delay_bug = modifier);
+        } else if modifier == "cycle_stash" {
+            try_insert!(cycle_stash = modifier);
         } else if modifier == "no_hash" {
             try_insert!(no_hash = modifier);
         } else if modifier == "anon" {
@@ -208,6 +214,7 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
         desc,
         fatal_cycle,
         cycle_delay_bug,
+        cycle_stash,
         no_hash,
         anon,
         eval_always,
@@ -329,6 +336,7 @@ pub fn rustc_queries(input: TokenStream) -> TokenStream {
             fatal_cycle,
             arena_cache,
             cycle_delay_bug,
+            cycle_stash,
             no_hash,
             anon,
             eval_always,

compiler/rustc_middle/src/query/mod.rs

@@ -251,6 +251,7 @@ rustc_queries! {
             "computing type of opaque `{path}`",
             path = tcx.def_path_str(key),
         }
+        cycle_stash
     }
 
     query type_alias_is_lazy(key: DefId) -> bool {

compiler/rustc_passes/messages.ftl

@@ -393,6 +393,9 @@ passes_invalid_attr_at_crate_level =
     `{$name}` attribute cannot be used at crate level
     .suggestion = perhaps you meant to use an outer attribute
 
+passes_invalid_attr_at_crate_level_item =
+    the inner attribute doesn't annotate this {$kind}
+
 passes_invalid_deprecation_version =
     invalid deprecation version found
     .label = invalid deprecation version

compiler/rustc_passes/src/check_attr.rs

@@ -2534,10 +2534,30 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
         if attr.style == AttrStyle::Inner {
             for attr_to_check in ATTRS_TO_CHECK {
                 if attr.has_name(*attr_to_check) {
+                    let item = tcx
+                        .hir()
+                        .items()
+                        .map(|id| tcx.hir().item(id))
+                        .find(|item| !item.span.is_dummy()) // Skip prelude `use`s
+                        .map(|item| errors::ItemFollowingInnerAttr {
+                            span: item.ident.span,
+                            kind: item.kind.descr(),
+                        });
                     tcx.sess.emit_err(errors::InvalidAttrAtCrateLevel {
                         span: attr.span,
-                        snippet: tcx.sess.source_map().span_to_snippet(attr.span).ok(),
+                        sugg_span: tcx
+                            .sess
+                            .source_map()
+                            .span_to_snippet(attr.span)
+                            .ok()
+                            .filter(|src| src.starts_with("#!["))
+                            .map(|_| {
+                                attr.span
+                                    .with_lo(attr.span.lo() + BytePos(1))
+                                    .with_hi(attr.span.lo() + BytePos(2))
+                            }),
                         name: *attr_to_check,
+                        item,
                     });
                 }
             }

compiler/rustc_passes/src/errors.rs

@@ -856,8 +856,15 @@ pub struct UnknownLangItem {
 
 pub struct InvalidAttrAtCrateLevel {
     pub span: Span,
-    pub snippet: Option<String>,
+    pub sugg_span: Option<Span>,
     pub name: Symbol,
+    pub item: Option<ItemFollowingInnerAttr>,
+}
+
+#[derive(Clone, Copy)]
+pub struct ItemFollowingInnerAttr {
+    pub span: Span,
+    pub kind: &'static str,
 }
 
 impl IntoDiagnostic<'_> for InvalidAttrAtCrateLevel {
@@ -871,15 +878,18 @@ impl IntoDiagnostic<'_> for InvalidAttrAtCrateLevel {
         diag.set_arg("name", self.name);
         // Only emit an error with a suggestion if we can create a string out
         // of the attribute span
-        if let Some(src) = self.snippet {
-            let replacement = src.replace("#!", "#");
+        if let Some(span) = self.sugg_span {
             diag.span_suggestion_verbose(
-                self.span,
+                span,
                 fluent::passes_suggestion,
-                replacement,
+                String::new(),
                 rustc_errors::Applicability::MachineApplicable,
             );
         }
+        if let Some(item) = self.item {
+            diag.set_arg("kind", item.kind);
+            diag.span_label(item.span, fluent::passes_invalid_attr_at_crate_level_item);
+        }
         diag
     }
 }

compiler/rustc_query_impl/src/plumbing.rs

@@ -197,6 +197,9 @@ macro_rules! handle_cycle_error {
     ([(fatal_cycle) $($rest:tt)*]) => {{
         rustc_query_system::HandleCycleError::Fatal
     }};
+    ([(cycle_stash) $($rest:tt)*]) => {{
+        rustc_query_system::HandleCycleError::Stash
+    }};
     ([(cycle_delay_bug) $($rest:tt)*]) => {{
         rustc_query_system::HandleCycleError::DelayBug
     }};

compiler/rustc_query_system/src/error.rs

@@ -15,6 +15,7 @@ pub enum HandleCycleError {
     Error,
     Fatal,
     DelayBug,
+    Stash,
 }
 
 #[derive(Subdiagnostic)]

compiler/rustc_query_system/src/query/plumbing.rs

@@ -19,7 +19,7 @@ use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::sync::Lock;
 #[cfg(parallel_compiler)]
 use rustc_data_structures::{outline, sync};
-use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, FatalError};
+use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, FatalError, StashKey};
 use rustc_span::{Span, DUMMY_SP};
 use std::cell::Cell;
 use std::collections::hash_map::Entry;
@@ -133,6 +133,17 @@ where
             let guar = error.delay_as_bug();
             query.value_from_cycle_error(*qcx.dep_context(), &cycle_error.cycle, guar)
         }
+        Stash => {
+            let guar = if let Some(root) = cycle_error.cycle.first()
+                && let Some(span) = root.query.span
+            {
+                error.stash(span, StashKey::Cycle);
+                qcx.dep_context().sess().delay_span_bug(span, "delayed cycle error")
+            } else {
+                error.emit()
+            };
+            query.value_from_cycle_error(*qcx.dep_context(), &cycle_error.cycle, guar)
+        }
     }
 }
 

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -1283,11 +1283,15 @@ impl<'tcx> Stable<'tcx> for ty::Const<'tcx> {
         let kind = match self.kind() {
             ty::Value(val) => {
                 let const_val = tables.tcx.valtree_to_const_val((self.ty(), val));
-                stable_mir::ty::ConstantKind::Allocated(alloc::new_allocation(
-                    self.ty(),
-                    const_val,
-                    tables,
-                ))
+                if matches!(const_val, mir::ConstValue::ZeroSized) {
+                    ConstantKind::ZeroSized
+                } else {
+                    stable_mir::ty::ConstantKind::Allocated(alloc::new_allocation(
+                        self.ty(),
+                        const_val,
+                        tables,
+                    ))
+                }
             }
             ty::ParamCt(param) => stable_mir::ty::ConstantKind::Param(param.stable(tables)),
             ty::ErrorCt(_) => unreachable!(),
@@ -1401,6 +1405,11 @@ impl<'tcx> Stable<'tcx> for rustc_middle::mir::Const<'tcx> {
                 let id = tables.intern_const(*self);
                 Const::new(kind, ty, id)
             }
+            mir::Const::Val(val, ty) if matches!(val, mir::ConstValue::ZeroSized) => {
+                let ty = ty.stable(tables);
+                let id = tables.intern_const(*self);
+                Const::new(ConstantKind::ZeroSized, ty, id)
+            }
             mir::Const::Val(val, ty) => {
                 let kind = ConstantKind::Allocated(alloc::new_allocation(ty, val, tables));
                 let ty = ty.stable(tables);

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

@@ -3104,6 +3104,13 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 );
             }
         };
+
+        if let Some(diag) =
+            self.tcx.sess.diagnostic().steal_diagnostic(self.tcx.def_span(def_id), StashKey::Cycle)
+        {
+            diag.cancel();
+        }
+
         err
     }
 

compiler/stable_mir/src/ty.rs

@@ -444,6 +444,9 @@ pub enum ConstantKind {
     Allocated(Allocation),
     Unevaluated(UnevaluatedConst),
     Param(ParamConst),
+    /// Store ZST constants.
+    /// We have to special handle these constants since its type might be generic.
+    ZeroSized,
 }
 
 #[derive(Clone, Debug)]

compiler/stable_mir/src/visitor.rs

@@ -50,7 +50,7 @@ impl Visitable for Const {
         match &self.kind() {
             super::ty::ConstantKind::Allocated(alloc) => alloc.visit(visitor)?,
             super::ty::ConstantKind::Unevaluated(uv) => uv.visit(visitor)?,
-            super::ty::ConstantKind::Param(_) => {}
+            super::ty::ConstantKind::Param(_) | super::ty::ConstantKind::ZeroSized => {}
         }
         self.ty().visit(visitor)
     }

library/core/src/iter/traits/iterator.rs

@@ -2142,7 +2142,7 @@ pub trait Iterator {
     /// passed collection. The collection is then returned, so the call chain
     /// can be continued.
     ///
-    /// This is useful when you already have a collection and wants to add
+    /// This is useful when you already have a collection and want to add
     /// the iterator items to it.
     ///
     /// This method is a convenience method to call [Extend::extend](trait.Extend.html),

library/std/src/thread/mod.rs

@@ -545,6 +545,13 @@ impl Builder {
             scope_data.increment_num_running_threads();
         }
 
+        let main = Box::new(main);
+        #[cfg(bootstrap)]
+        let main =
+            unsafe { mem::transmute::<Box<dyn FnOnce() + 'a>, Box<dyn FnOnce() + 'static>>(main) };
+        #[cfg(not(bootstrap))]
+        let main = unsafe { Box::from_raw(Box::into_raw(main) as *mut (dyn FnOnce() + 'static)) };
+
         Ok(JoinInner {
             // SAFETY:
             //
@@ -559,14 +566,7 @@ impl Builder {
             // Similarly, the `sys` implementation must guarantee that no references to the closure
             // exist after the thread has terminated, which is signaled by `Thread::join`
             // returning.
-            native: unsafe {
-                imp::Thread::new(
-                    stack_size,
-                    mem::transmute::<Box<dyn FnOnce() + 'a>, Box<dyn FnOnce() + 'static>>(
-                        Box::new(main),
-                    ),
-                )?
-            },
+            native: unsafe { imp::Thread::new(stack_size, main)? },
             thread: my_thread,
             packet: my_packet,
         })

src/doc/rustc/src/profile-guided-optimization.md

@@ -145,3 +145,26 @@ in Clang's documentation is therefore an interesting read for anyone who wants
 to use PGO with Rust.
 
 [clang-pgo]: https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization
+
+## Community Maintained Tools
+
+As an alternative to directly using the compiler for Profile-Guided Optimization,
+you may choose to go with `cargo-pgo`, which has an intuitive command-line API
+and saves you the trouble of doing all the manual work. You can read more about
+it in their repository accessible from this link: https://github.com/Kobzol/cargo-pgo
+
+For the sake of completeness, here are the corresponding steps using `cargo-pgo`:
+
+```bash
+# Install if you haven't already
+cargo install cargo-pgo
+
+cargo pgo build
+cargo pgo optimize
+```
+
+These steps will do the following just as before:
+
+1. Build an instrumented binary from the source code.
+2. Run the instrumented binary to gather PGO profiles.
+3. Use the gathered PGO profiles from the last step to build an optimized binary.

tests/ui/attributes/unix_sigpipe/unix_sigpipe-crate.stderr

@@ -3,11 +3,15 @@ error: `unix_sigpipe` attribute cannot be used at crate level
    |
 LL | #![unix_sigpipe = "inherit"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | fn main() {}
+   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
-LL | #[unix_sigpipe = "inherit"]
-   | ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+LL - #![unix_sigpipe = "inherit"]
+LL + #[unix_sigpipe = "inherit"]
+   |
 
 error: aborting due to previous error