Auto merge of #96253 - Dylan-DPC:rollup-87hpds5, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #93313 (Check if call return type is visibly uninhabited when building MIR)
 - #96160 (Miri/interpreter debugging tweaks)
 - #96167 (Replace sys/unix/weak AtomicUsize with AtomicPtr)
 - #96168 (Improve AddrParseError description)
 - #96206 (Use sys::unix::locks::futex* on wasm+atomics.)
 - #96234 (remove_dir_all_recursive: treat ELOOP the same as ENOTDIR)

Failed merges:

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

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -679,7 +679,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         return_place: Option<&PlaceTy<'tcx, M::PointerTag>>,
         return_to_block: StackPopCleanup,
     ) -> InterpResult<'tcx> {
-        debug!("body: {:#?}", body);
+        trace!("body: {:#?}", body);
         // first push a stack frame so we have access to the local substs
         let pre_frame = Frame {
             body,
@@ -836,7 +836,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             return Ok(());
         }
 
-        debug!("locals: {:#?}", frame.locals);
+        trace!("locals: {:#?}", frame.locals);
 
         // Cleanup: deallocate all locals that are backed by an allocation.
         for local in &frame.locals {

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -870,9 +870,17 @@ impl<'tcx, 'a, Tag: Provenance, Extra> AllocRefMut<'a, 'tcx, Tag, Extra> {
         range: AllocRange,
         val: ScalarMaybeUninit<Tag>,
     ) -> InterpResult<'tcx> {
+        let range = self.range.subrange(range);
+        debug!(
+            "write_scalar in {} at {:#x}, size {}: {:?}",
+            self.alloc_id,
+            range.start.bytes(),
+            range.size.bytes(),
+            val
+        );
         Ok(self
             .alloc
-            .write_scalar(&self.tcx, self.range.subrange(range), val)
+            .write_scalar(&self.tcx, range, val)
             .map_err(|e| e.to_interp_error(self.alloc_id))?)
     }
 
@@ -895,10 +903,19 @@ impl<'tcx, 'a, Tag: Provenance, Extra> AllocRefMut<'a, 'tcx, Tag, Extra> {
 
 impl<'tcx, 'a, Tag: Provenance, Extra> AllocRef<'a, 'tcx, Tag, Extra> {
     pub fn read_scalar(&self, range: AllocRange) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {
-        Ok(self
+        let range = self.range.subrange(range);
+        let res = self
             .alloc
-            .read_scalar(&self.tcx, self.range.subrange(range))
-            .map_err(|e| e.to_interp_error(self.alloc_id))?)
+            .read_scalar(&self.tcx, range)
+            .map_err(|e| e.to_interp_error(self.alloc_id))?;
+        debug!(
+            "read_scalar in {} at {:#x}, size {}: {:?}",
+            self.alloc_id,
+            range.start.bytes(),
+            range.size.bytes(),
+            res
+        );
+        Ok(res)
     }
 
     pub fn read_ptr_sized(&self, offset: Size) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -515,6 +515,9 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
             if Tag::ERR_ON_PARTIAL_PTR_OVERWRITE {
                 return Err(AllocError::PartialPointerOverwrite(first));
             }
+            warn!(
+                "Partial pointer overwrite! De-initializing memory at offsets {first:?}..{start:?}."
+            );
             self.init_mask.set_range(first, start, false);
         }
         if last > end {
@@ -523,10 +526,15 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
                     last - cx.data_layout().pointer_size,
                 ));
             }
+            warn!(
+                "Partial pointer overwrite! De-initializing memory at offsets {end:?}..{last:?}."
+            );
             self.init_mask.set_range(end, last, false);
         }
 
         // Forget all the relocations.
+        // Since relocations do not overlap, we know that removing until `last` (exclusive) is fine,
+        // i.e., this will not remove any other relocations just after the ones we care about.
         self.relocations.0.remove_range(first..last);
 
         Ok(())

compiler/rustc_mir_build/src/build/expr/into.rs

@@ -255,10 +255,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         func: fun,
                         args,
                         cleanup: None,
-                        // FIXME(varkor): replace this with an uninhabitedness-based check.
-                        // This requires getting access to the current module to call
-                        // `tcx.is_ty_uninhabited_from`, which is currently tricky to do.
-                        destination: if expr.ty.is_never() {
+                        // The presence or absence of a return edge affects control-flow sensitive
+                        // MIR checks and ultimately whether code is accepted or not. We can only
+                        // omit the return edge if a return type is visibly uninhabited to a module
+                        // that makes the call.
+                        destination: if this.tcx.is_ty_uninhabited_from(
+                            this.parent_module,
+                            expr.ty,
+                            this.param_env,
+                        ) {
                             None
                         } else {
                             Some((destination, success))

compiler/rustc_mir_build/src/build/mod.rs

@@ -350,6 +350,7 @@ struct Builder<'a, 'tcx> {
 
     def_id: DefId,
     hir_id: hir::HirId,
+    parent_module: DefId,
     check_overflow: bool,
     fn_span: Span,
     arg_count: usize,
@@ -807,15 +808,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         );
 
         let lint_level = LintLevel::Explicit(hir_id);
+        let param_env = tcx.param_env(def.did);
         let mut builder = Builder {
             thir,
             tcx,
             infcx,
             typeck_results: tcx.typeck_opt_const_arg(def),
             region_scope_tree: tcx.region_scope_tree(def.did),
-            param_env: tcx.param_env(def.did),
+            param_env,
             def_id: def.did.to_def_id(),
             hir_id,
+            parent_module: tcx.parent_module(hir_id).to_def_id(),
             check_overflow,
             cfg: CFG { basic_blocks: IndexVec::new() },
             fn_span: span,

library/std/src/net/parser.rs

@@ -59,12 +59,12 @@ impl<'a> Parser<'a> {
 
     /// Run a parser, but fail if the entire input wasn't consumed.
     /// Doesn't run atomically.
-    fn parse_with<T, F>(&mut self, inner: F) -> Result<T, AddrParseError>
+    fn parse_with<T, F>(&mut self, inner: F, kind: AddrKind) -> Result<T, AddrParseError>
     where
         F: FnOnce(&mut Parser<'_>) -> Option<T>,
     {
         let result = inner(self);
-        if self.state.is_empty() { result } else { None }.ok_or(AddrParseError(()))
+        if self.state.is_empty() { result } else { None }.ok_or(AddrParseError(kind))
     }
 
     /// Peek the next character from the input
@@ -278,7 +278,7 @@ impl<'a> Parser<'a> {
 impl FromStr for IpAddr {
     type Err = AddrParseError;
     fn from_str(s: &str) -> Result<IpAddr, AddrParseError> {
-        Parser::new(s).parse_with(|p| p.read_ip_addr())
+        Parser::new(s).parse_with(|p| p.read_ip_addr(), AddrKind::Ip)
     }
 }
 
@@ -288,9 +288,9 @@ impl FromStr for Ipv4Addr {
     fn from_str(s: &str) -> Result<Ipv4Addr, AddrParseError> {
         // don't try to parse if too long
         if s.len() > 15 {
-            Err(AddrParseError(()))
+            Err(AddrParseError(AddrKind::Ipv4))
         } else {
-            Parser::new(s).parse_with(|p| p.read_ipv4_addr())
+            Parser::new(s).parse_with(|p| p.read_ipv4_addr(), AddrKind::Ipv4)
         }
     }
 }
@@ -299,34 +299,44 @@ impl FromStr for Ipv4Addr {
 impl FromStr for Ipv6Addr {
     type Err = AddrParseError;
     fn from_str(s: &str) -> Result<Ipv6Addr, AddrParseError> {
-        Parser::new(s).parse_with(|p| p.read_ipv6_addr())
+        Parser::new(s).parse_with(|p| p.read_ipv6_addr(), AddrKind::Ipv6)
     }
 }
 
 #[stable(feature = "socket_addr_from_str", since = "1.5.0")]
 impl FromStr for SocketAddrV4 {
     type Err = AddrParseError;
     fn from_str(s: &str) -> Result<SocketAddrV4, AddrParseError> {
-        Parser::new(s).parse_with(|p| p.read_socket_addr_v4())
+        Parser::new(s).parse_with(|p| p.read_socket_addr_v4(), AddrKind::SocketV4)
     }
 }
 
 #[stable(feature = "socket_addr_from_str", since = "1.5.0")]
 impl FromStr for SocketAddrV6 {
     type Err = AddrParseError;
     fn from_str(s: &str) -> Result<SocketAddrV6, AddrParseError> {
-        Parser::new(s).parse_with(|p| p.read_socket_addr_v6())
+        Parser::new(s).parse_with(|p| p.read_socket_addr_v6(), AddrKind::SocketV6)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl FromStr for SocketAddr {
     type Err = AddrParseError;
     fn from_str(s: &str) -> Result<SocketAddr, AddrParseError> {
-        Parser::new(s).parse_with(|p| p.read_socket_addr())
+        Parser::new(s).parse_with(|p| p.read_socket_addr(), AddrKind::Socket)
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+enum AddrKind {
+    Ip,
+    Ipv4,
+    Ipv6,
+    Socket,
+    SocketV4,
+    SocketV6,
+}
+
 /// An error which can be returned when parsing an IP address or a socket address.
 ///
 /// This error is used as the error type for the [`FromStr`] implementation for
@@ -353,7 +363,7 @@ impl FromStr for SocketAddr {
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct AddrParseError(());
+pub struct AddrParseError(AddrKind);
 
 #[stable(feature = "addr_parse_error_error", since = "1.4.0")]
 impl fmt::Display for AddrParseError {
@@ -367,6 +377,13 @@ impl fmt::Display for AddrParseError {
 impl Error for AddrParseError {
     #[allow(deprecated)]
     fn description(&self) -> &str {
-        "invalid IP address syntax"
+        match self.0 {
+            AddrKind::Ip => "invalid IP address syntax",
+            AddrKind::Ipv4 => "invalid IPv4 address syntax",
+            AddrKind::Ipv6 => "invalid IPv6 address syntax",
+            AddrKind::Socket => "invalid socket address syntax",
+            AddrKind::SocketV4 => "invalid IPv4 socket address syntax",
+            AddrKind::SocketV6 => "invalid IPv6 socket address syntax",
+        }
     }
 }

library/std/src/sys/unix/fs.rs

@@ -1647,8 +1647,9 @@ mod remove_dir_impl {
     fn remove_dir_all_recursive(parent_fd: Option<RawFd>, path: &CStr) -> io::Result<()> {
         // try opening as directory
         let fd = match openat_nofollow_dironly(parent_fd, &path) {
-            Err(err) if err.raw_os_error() == Some(libc::ENOTDIR) => {
+            Err(err) if matches!(err.raw_os_error(), Some(libc::ENOTDIR | libc::ELOOP)) => {
                 // not a directory - don't traverse further
+                // (for symlinks, older Linux kernels may return ELOOP instead of ENOTDIR)
                 return match parent_fd {
                     // unlink...
                     Some(parent_fd) => {

library/std/src/sys/unix/weak.rs

@@ -25,7 +25,8 @@
 use crate::ffi::CStr;
 use crate::marker::PhantomData;
 use crate::mem;
-use crate::sync::atomic::{self, AtomicUsize, Ordering};
+use crate::ptr;
+use crate::sync::atomic::{self, AtomicPtr, Ordering};
 
 // We can use true weak linkage on ELF targets.
 #[cfg(not(any(target_os = "macos", target_os = "ios")))]
@@ -83,25 +84,25 @@ pub(crate) macro dlsym {
 }
 pub(crate) struct DlsymWeak<F> {
     name: &'static str,
-    addr: AtomicUsize,
+    func: AtomicPtr<libc::c_void>,
     _marker: PhantomData<F>,
 }
 
 impl<F> DlsymWeak<F> {
     pub(crate) const fn new(name: &'static str) -> Self {
-        DlsymWeak { name, addr: AtomicUsize::new(1), _marker: PhantomData }
+        DlsymWeak { name, func: AtomicPtr::new(ptr::invalid_mut(1)), _marker: PhantomData }
     }
 
     #[inline]
     pub(crate) fn get(&self) -> Option<F> {
         unsafe {
             // Relaxed is fine here because we fence before reading through the
             // pointer (see the comment below).
-            match self.addr.load(Ordering::Relaxed) {
-                1 => self.initialize(),
-                0 => None,
-                addr => {
-                    let func = mem::transmute_copy::<usize, F>(&addr);
+            match self.func.load(Ordering::Relaxed) {
+                func if func.addr() == 1 => self.initialize(),
+                func if func.is_null() => None,
+                func => {
+                    let func = mem::transmute_copy::<*mut libc::c_void, F>(&func);
                     // The caller is presumably going to read through this value
                     // (by calling the function we've dlsymed). This means we'd
                     // need to have loaded it with at least C11's consume
@@ -129,25 +130,22 @@ impl<F> DlsymWeak<F> {
     // Cold because it should only happen during first-time initialization.
     #[cold]
     unsafe fn initialize(&self) -> Option<F> {
-        assert_eq!(mem::size_of::<F>(), mem::size_of::<usize>());
+        assert_eq!(mem::size_of::<F>(), mem::size_of::<*mut libc::c_void>());
 
         let val = fetch(self.name);
         // This synchronizes with the acquire fence in `get`.
-        self.addr.store(val, Ordering::Release);
+        self.func.store(val, Ordering::Release);
 
-        match val {
-            0 => None,
-            addr => Some(mem::transmute_copy::<usize, F>(&addr)),
-        }
+        if val.is_null() { None } else { Some(mem::transmute_copy::<*mut libc::c_void, F>(&val)) }
     }
 }
 
-unsafe fn fetch(name: &str) -> usize {
+unsafe fn fetch(name: &str) -> *mut libc::c_void {
     let name = match CStr::from_bytes_with_nul(name.as_bytes()) {
         Ok(cstr) => cstr,
-        Err(..) => return 0,
+        Err(..) => return ptr::null_mut(),
     };
-    libc::dlsym(libc::RTLD_DEFAULT, name.as_ptr()) as usize
+    libc::dlsym(libc::RTLD_DEFAULT, name.as_ptr())
 }
 
 #[cfg(not(any(target_os = "linux", target_os = "android")))]