Auto merge of #124084 - matthiaskrgr:rollup-h42psbx, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #116957 (meta: notify #t-rustdoc Zulip stream on backport nominations)
 - #122201 (Document overrides of `clone_from()` in core/std)
 - #122723 (Use same file permissions for ar_archive_writer as the LLVM archive writer)
 - #124030 (interpret: pass MemoryKind to adjust_alloc_base_pointer)
 - #124037 (Don't ascend into parent bodies when collecting stmts for possible return suggestion)
 - #124049 (Stabilize `const_io_structs`)
 - #124062 (Add another expression to weird-exprs.rs)
 - #124066 (Don't error on subtyping of equal types)
 - #124073 (Remove libc from rust_get_test_int uses)

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

Author: bors

compiler/rustc_codegen_ssa/src/back/archive.rs

@@ -13,7 +13,7 @@ use object::read::macho::FatArch;
 use tempfile::Builder as TempFileBuilder;
 
 use std::error::Error;
-use std::fs::File;
+use std::fs::{self, File};
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
 
@@ -280,22 +280,33 @@ impl<'a> ArArchiveBuilder<'a> {
         // This prevents programs (including rustc) from attempting to read a partial archive.
         // It also enables writing an archive with the same filename as a dependency on Windows as
         // required by a test.
-        let mut archive_tmpfile = TempFileBuilder::new()
+        // The tempfile crate currently uses 0o600 as mode for the temporary files and directories
+        // it creates. We need it to be the default mode for back compat reasons however. (See
+        // #107495) To handle this we are telling tempfile to create a temporary directory instead
+        // and then inside this directory create a file using File::create.
+        let archive_tmpdir = TempFileBuilder::new()
             .suffix(".temp-archive")
-            .tempfile_in(output.parent().unwrap_or_else(|| Path::new("")))
-            .map_err(|err| io_error_context("couldn't create a temp file", err))?;
+            .tempdir_in(output.parent().unwrap_or_else(|| Path::new("")))
+            .map_err(|err| {
+                io_error_context("couldn't create a directory for the temp file", err)
+            })?;
+        let archive_tmpfile_path = archive_tmpdir.path().join("tmp.a");
+        let mut archive_tmpfile = File::create_new(&archive_tmpfile_path)
+            .map_err(|err| io_error_context("couldn't create the temp file", err))?;
 
-        write_archive_to_stream(archive_tmpfile.as_file_mut(), &entries, archive_kind, false)?;
+        write_archive_to_stream(&mut archive_tmpfile, &entries, archive_kind, false)?;
 
         let any_entries = !entries.is_empty();
         drop(entries);
         // Drop src_archives to unmap all input archives, which is necessary if we want to write the
         // output archive to the same location as an input archive on Windows.
         drop(self.src_archives);
 
-        archive_tmpfile
-            .persist(output)
-            .map_err(|err| io_error_context("failed to rename archive file", err.error))?;
+        fs::rename(archive_tmpfile_path, output)
+            .map_err(|err| io_error_context("failed to rename archive file", err))?;
+        archive_tmpdir
+            .close()
+            .map_err(|err| io_error_context("failed to remove temporary directory", err))?;
 
         Ok(any_entries)
     }

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -288,28 +288,19 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
     }
 
     /// Return the `AllocId` for the given thread-local static in the current thread.
-    fn thread_local_static_base_pointer(
+    fn thread_local_static_pointer(
         _ecx: &mut InterpCx<'mir, 'tcx, Self>,
         def_id: DefId,
     ) -> InterpResult<'tcx, Pointer<Self::Provenance>> {
         throw_unsup!(ThreadLocalStatic(def_id))
     }
 
-    /// Return the root pointer for the given `extern static`.
-    fn extern_static_base_pointer(
+    /// Return the `AllocId` for the given `extern static`.
+    fn extern_static_pointer(
         ecx: &InterpCx<'mir, 'tcx, Self>,
         def_id: DefId,
     ) -> InterpResult<'tcx, Pointer<Self::Provenance>>;
 
-    /// Return a "base" pointer for the given allocation: the one that is used for direct
-    /// accesses to this static/const/fn allocation, or the one returned from the heap allocator.
-    ///
-    /// Not called on `extern` or thread-local statics (those use the methods above).
-    fn adjust_alloc_base_pointer(
-        ecx: &InterpCx<'mir, 'tcx, Self>,
-        ptr: Pointer,
-    ) -> InterpResult<'tcx, Pointer<Self::Provenance>>;
-
     /// "Int-to-pointer cast"
     fn ptr_from_addr_cast(
         ecx: &InterpCx<'mir, 'tcx, Self>,
@@ -336,6 +327,8 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
 
     /// Called to adjust allocations to the Provenance and AllocExtra of this machine.
     ///
+    /// If `alloc` contains pointers, then they are all pointing to globals.
+    ///
     /// The way we construct allocations is to always first construct it without extra and then add
     /// the extra. This keeps uniform code paths for handling both allocations created by CTFE for
     /// globals, and allocations created by Miri during evaluation.
@@ -354,6 +347,19 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
         kind: Option<MemoryKind<Self::MemoryKind>>,
     ) -> InterpResult<'tcx, Cow<'b, Allocation<Self::Provenance, Self::AllocExtra, Self::Bytes>>>;
 
+    /// Return a "root" pointer for the given allocation: the one that is used for direct
+    /// accesses to this static/const/fn allocation, or the one returned from the heap allocator.
+    ///
+    /// Not called on `extern` or thread-local statics (those use the methods above).
+    ///
+    /// `kind` is the kind of the allocation the pointer points to; it can be `None` when
+    /// it's a global and `GLOBAL_KIND` is `None`.
+    fn adjust_alloc_root_pointer(
+        ecx: &InterpCx<'mir, 'tcx, Self>,
+        ptr: Pointer,
+        kind: Option<MemoryKind<Self::MemoryKind>>,
+    ) -> InterpResult<'tcx, Pointer<Self::Provenance>>;
+
     /// Evaluate the inline assembly.
     ///
     /// This should take care of jumping to the next block (one of `targets`) when asm goto
@@ -592,7 +598,7 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
         Ok(alloc)
     }
 
-    fn extern_static_base_pointer(
+    fn extern_static_pointer(
         ecx: &InterpCx<$mir, $tcx, Self>,
         def_id: DefId,
     ) -> InterpResult<$tcx, Pointer> {
@@ -601,9 +607,10 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
     }
 
     #[inline(always)]
-    fn adjust_alloc_base_pointer(
+    fn adjust_alloc_root_pointer(
         _ecx: &InterpCx<$mir, $tcx, Self>,
         ptr: Pointer<CtfeProvenance>,
+        _kind: Option<MemoryKind<Self::MemoryKind>>,
     ) -> InterpResult<$tcx, Pointer<CtfeProvenance>> {
         Ok(ptr)
     }

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -165,7 +165,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ///
     /// This function can fail only if `ptr` points to an `extern static`.
     #[inline]
-    pub fn global_base_pointer(
+    pub fn global_root_pointer(
         &self,
         ptr: Pointer<CtfeProvenance>,
     ) -> InterpResult<'tcx, Pointer<M::Provenance>> {
@@ -178,12 +178,18 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 bug!("global memory cannot point to thread-local static")
             }
             Some(GlobalAlloc::Static(def_id)) if self.tcx.is_foreign_item(def_id) => {
-                return M::extern_static_base_pointer(self, def_id);
+                return M::extern_static_pointer(self, def_id);
+            }
+            None => {
+                assert!(
+                    self.memory.extra_fn_ptr_map.contains_key(&alloc_id),
+                    "{alloc_id:?} is neither global nor a function pointer"
+                );
             }
             _ => {}
         }
         // And we need to get the provenance.
-        M::adjust_alloc_base_pointer(self, ptr)
+        M::adjust_alloc_root_pointer(self, ptr, M::GLOBAL_KIND.map(MemoryKind::Machine))
     }
 
     pub fn fn_ptr(&mut self, fn_val: FnVal<'tcx, M::ExtraFnVal>) -> Pointer<M::Provenance> {
@@ -197,9 +203,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 id
             }
         };
-        // Functions are global allocations, so make sure we get the right base pointer.
+        // Functions are global allocations, so make sure we get the right root pointer.
         // We know this is not an `extern static` so this cannot fail.
-        self.global_base_pointer(Pointer::from(id)).unwrap()
+        self.global_root_pointer(Pointer::from(id)).unwrap()
     }
 
     pub fn allocate_ptr(
@@ -240,7 +246,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         );
         let alloc = M::adjust_allocation(self, id, Cow::Owned(alloc), Some(kind))?;
         self.memory.alloc_map.insert(id, (kind, alloc.into_owned()));
-        M::adjust_alloc_base_pointer(self, Pointer::from(id))
+        M::adjust_alloc_root_pointer(self, Pointer::from(id), Some(kind))
     }
 
     pub fn reallocate_ptr(

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -764,15 +764,15 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // Other cases need layout.
         let adjust_scalar = |scalar| -> InterpResult<'tcx, _> {
             Ok(match scalar {
-                Scalar::Ptr(ptr, size) => Scalar::Ptr(self.global_base_pointer(ptr)?, size),
+                Scalar::Ptr(ptr, size) => Scalar::Ptr(self.global_root_pointer(ptr)?, size),
                 Scalar::Int(int) => Scalar::Int(int),
             })
         };
         let layout = from_known_layout(self.tcx, self.param_env, layout, || self.layout_of(ty))?;
         let imm = match val_val {
             mir::ConstValue::Indirect { alloc_id, offset } => {
                 // This is const data, no mutation allowed.
-                let ptr = self.global_base_pointer(Pointer::new(
+                let ptr = self.global_root_pointer(Pointer::new(
                     CtfeProvenance::from(alloc_id).as_immutable(),
                     offset,
                 ))?;
@@ -784,7 +784,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 // This is const data, no mutation allowed.
                 let alloc_id = self.tcx.reserve_and_set_memory_alloc(data);
                 let ptr = Pointer::new(CtfeProvenance::from(alloc_id).as_immutable(), Size::ZERO);
-                Immediate::new_slice(self.global_base_pointer(ptr)?.into(), meta, self)
+                Immediate::new_slice(self.global_root_pointer(ptr)?.into(), meta, self)
             }
         };
         Ok(OpTy { op: Operand::Immediate(imm), layout })

compiler/rustc_const_eval/src/interpret/place.rs

@@ -1010,7 +1010,7 @@ where
     ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {
         // This must be an allocation in `tcx`
         let _ = self.tcx.global_alloc(raw.alloc_id);
-        let ptr = self.global_base_pointer(Pointer::from(raw.alloc_id))?;
+        let ptr = self.global_root_pointer(Pointer::from(raw.alloc_id))?;
         let layout = self.layout_of(raw.ty)?;
         Ok(self.ptr_to_mplace(ptr.into(), layout))
     }

compiler/rustc_const_eval/src/interpret/step.rs

@@ -144,7 +144,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         use rustc_middle::mir::Rvalue::*;
         match *rvalue {
             ThreadLocalRef(did) => {
-                let ptr = M::thread_local_static_base_pointer(self, did)?;
+                let ptr = M::thread_local_static_pointer(self, did)?;
                 self.write_pointer(ptr, &dest)?;
             }
 

compiler/rustc_const_eval/src/interpret/traits.rs

@@ -28,7 +28,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         ensure_monomorphic_enough(*self.tcx, poly_trait_ref)?;
 
         let vtable_symbolic_allocation = self.tcx.reserve_and_set_vtable_alloc(ty, poly_trait_ref);
-        let vtable_ptr = self.global_base_pointer(Pointer::from(vtable_symbolic_allocation))?;
+        let vtable_ptr = self.global_root_pointer(Pointer::from(vtable_symbolic_allocation))?;
         Ok(vtable_ptr.into())
     }
 

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -2011,12 +2011,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         for (span, code) in errors_causecode {
             self.dcx().try_steal_modify_and_emit_err(span, StashKey::MaybeForgetReturn, |err| {
                 if let Some(fn_sig) = self.body_fn_sig()
-                    && let ExprBindingObligation(_, _, hir_id, ..) = code
+                    && let ExprBindingObligation(_, _, binding_hir_id, ..) = code
                     && !fn_sig.output().is_unit()
                 {
                     let mut block_num = 0;
                     let mut found_semi = false;
-                    for (_, node) in self.tcx.hir().parent_iter(hir_id) {
+                    for (hir_id, node) in self.tcx.hir().parent_iter(binding_hir_id) {
+                        // Don't proceed into parent bodies
+                        if hir_id.owner != binding_hir_id.owner {
+                            break;
+                        }
                         match node {
                             hir::Node::Stmt(stmt) => {
                                 if let hir::StmtKind::Semi(expr) = stmt.kind {

compiler/rustc_infer/src/infer/mod.rs

@@ -952,7 +952,7 @@ impl<'tcx> InferCtxt<'tcx> {
             // a test for it.
             (_, ty::Infer(ty::TyVar(_))) => {}
             (ty::Infer(ty::TyVar(_)), _) => {}
-            _ if (r_a, r_b).has_opaque_types() => {
+            _ if r_a != r_b && (r_a, r_b).has_opaque_types() => {
                 span_bug!(
                     cause.span(),
                     "opaque types got hidden types registered from within subtype predicate: {r_a:?} vs {r_b:?}"

library/alloc/src/boxed.rs

@@ -2088,11 +2088,29 @@ impl<T: Clone, A: Allocator + Clone> Clone for Box<[T], A> {
         self.to_vec_in(alloc).into_boxed_slice()
     }
 
-    fn clone_from(&mut self, other: &Self) {
-        if self.len() == other.len() {
-            self.clone_from_slice(&other);
+    /// Copies `source`'s contents into `self` without creating a new allocation,
+    /// so long as the two are of the same length.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x = Box::new([5, 6, 7]);
+    /// let mut y = Box::new([8, 9, 10]);
+    /// let yp: *const [i32] = &*y;
+    ///
+    /// y.clone_from(&x);
+    ///
+    /// // The value is the same
+    /// assert_eq!(x, y);
+    ///
+    /// // And no allocation occurred
+    /// assert_eq!(yp, &*y);
+    /// ```
+    fn clone_from(&mut self, source: &Self) {
+        if self.len() == source.len() {
+            self.clone_from_slice(&source);
         } else {
-            *self = other.clone();
+            *self = source.clone();
         }
     }
 }

library/alloc/src/collections/binary_heap/mod.rs

@@ -385,6 +385,12 @@ impl<T: Clone, A: Allocator + Clone> Clone for BinaryHeap<T, A> {
         BinaryHeap { data: self.data.clone() }
     }
 
+    /// Overwrites the contents of `self` with a clone of the contents of `source`.
+    ///
+    /// This method is preferred over simply assigning `source.clone()` to `self`,
+    /// as it avoids reallocation if possible.
+    ///
+    /// See [`Vec::clone_from()`] for more details.
     fn clone_from(&mut self, source: &Self) {
         self.data.clone_from(&source.data);
     }

library/alloc/src/collections/btree/set.rs

@@ -116,8 +116,8 @@ impl<T: Clone, A: Allocator + Clone> Clone for BTreeSet<T, A> {
         BTreeSet { map: self.map.clone() }
     }
 
-    fn clone_from(&mut self, other: &Self) {
-        self.map.clone_from(&other.map);
+    fn clone_from(&mut self, source: &Self) {
+        self.map.clone_from(&source.map);
     }
 }
 

library/alloc/src/collections/linked_list.rs

@@ -2126,16 +2126,22 @@ impl<T: Clone, A: Allocator + Clone> Clone for LinkedList<T, A> {
         list
     }
 
-    fn clone_from(&mut self, other: &Self) {
-        let mut iter_other = other.iter();
-        if self.len() > other.len() {
-            self.split_off(other.len());
+    /// Overwrites the contents of `self` with a clone of the contents of `source`.
+    ///
+    /// This method is preferred over simply assigning `source.clone()` to `self`,
+    /// as it avoids reallocation of the nodes of the linked list. Additionally,
+    /// if the element type `T` overrides `clone_from()`, this will reuse the
+    /// resources of `self`'s elements as well.
+    fn clone_from(&mut self, source: &Self) {
+        let mut source_iter = source.iter();
+        if self.len() > source.len() {
+            self.split_off(source.len());
         }
-        for (elem, elem_other) in self.iter_mut().zip(&mut iter_other) {
-            elem.clone_from(elem_other);
+        for (elem, source_elem) in self.iter_mut().zip(&mut source_iter) {
+            elem.clone_from(source_elem);
         }
-        if !iter_other.is_empty() {
-            self.extend(iter_other.cloned());
+        if !source_iter.is_empty() {
+            self.extend(source_iter.cloned());
         }
     }
 }

library/alloc/src/collections/vec_deque/mod.rs

@@ -113,9 +113,13 @@ impl<T: Clone, A: Allocator + Clone> Clone for VecDeque<T, A> {
         deq
     }
 
-    fn clone_from(&mut self, other: &Self) {
+    /// Overwrites the contents of `self` with a clone of the contents of `source`.
+    ///
+    /// This method is preferred over simply assigning `source.clone()` to `self`,
+    /// as it avoids reallocation if possible.
+    fn clone_from(&mut self, source: &Self) {
         self.clear();
-        self.extend(other.iter().cloned());
+        self.extend(source.iter().cloned());
     }
 }
 

library/alloc/src/string.rs

@@ -2097,6 +2097,10 @@ impl Clone for String {
         String { vec: self.vec.clone() }
     }
 
+    /// Clones the contents of `source` into `self`.
+    ///
+    /// This method is preferred over simply assigning `source.clone()` to `self`,
+    /// as it avoids reallocation if possible.
     fn clone_from(&mut self, source: &Self) {
         self.vec.clone_from(&source.vec);
     }