Auto merge of #3210 - rust-lang:rustup-2023-12-05, r=RalfJung

Automatic Rustup

Author: bors

rust-version

@@ -1 +1 @@
-c9808f87028e16d134438787cab3d4cc16d05fe2
+317d14a56cb8c748bf0e2f2afff89c2249ab4423

tests/fail/stacked_borrows/zst_slice.rs

@@ -1,11 +1,10 @@
 //@compile-flags: -Zmiri-strict-provenance
-//@error-in-other-file: /retag .* tag does not exist in the borrow stack/
 
 fn main() {
     unsafe {
         let a = [1, 2, 3];
         let s = &a[0..0];
         assert_eq!(s.len(), 0);
-        assert_eq!(*s.get_unchecked(1), 2);
+        assert_eq!(*s.as_ptr().add(1), 2); //~ ERROR: /retag .* tag does not exist in the borrow stack/
     }
 }

tests/fail/stacked_borrows/zst_slice.stderr

@@ -1,26 +1,22 @@
 error: Undefined Behavior: trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
-  --> RUSTLIB/core/src/slice/mod.rs:LL:CC
+  --> $DIR/zst_slice.rs:LL:CC
    |
-LL |         unsafe { &*index.get_unchecked(self) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |                  |
-   |                  trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
-   |                  this error occurs as part of retag at ALLOC[0x4..0x8]
+LL |         assert_eq!(*s.as_ptr().add(1), 2);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         |
+   |         trying to retag from <TAG> for SharedReadOnly permission at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
+   |         this error occurs as part of retag at ALLOC[0x4..0x8]
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> would have been created here, but this is a zero-size retag ([0x0..0x0]) so the tag in question does not exist anywhere
   --> $DIR/zst_slice.rs:LL:CC
    |
-LL |         assert_eq!(*s.get_unchecked(1), 2);
-   |                     ^^^^^^^^^^^^^^^^^^
+LL |         assert_eq!(*s.as_ptr().add(1), 2);
+   |                     ^^^^^^^^^^
    = note: BACKTRACE (of the first span):
-   = note: inside `core::slice::<impl [i32]>::get_unchecked::<usize>` at RUSTLIB/core/src/slice/mod.rs:LL:CC
-note: inside `main`
-  --> $DIR/zst_slice.rs:LL:CC
-   |
-LL |         assert_eq!(*s.get_unchecked(1), 2);
-   |                     ^^^^^^^^^^^^^^^^^^
+   = note: inside `main` at RUSTLIB/core/src/macros/mod.rs:LL:CC
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

tests/fail/uninit/uninit_byte_read.rs

@@ -1,7 +1,7 @@
 //@compile-flags: -Zmiri-disable-stacked-borrows
 fn main() {
     let v: Vec<u8> = Vec::with_capacity(10);
-    let undef = unsafe { *v.get_unchecked(5) }; //~ ERROR: uninitialized
+    let undef = unsafe { *v.as_ptr().add(5) }; //~ ERROR: uninitialized
     let x = undef + 1;
     panic!("this should never print: {}", x);
 }

tests/fail/uninit/uninit_byte_read.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
   --> $DIR/uninit_byte_read.rs:LL:CC
    |
-LL |     let undef = unsafe { *v.get_unchecked(5) };
-   |                          ^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+LL |     let undef = unsafe { *v.as_ptr().add(5) };
+   |                          ^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

tests/pass/float_nan.rs

@@ -20,8 +20,8 @@ use NaNKind::*;
 #[track_caller]
 fn check_all_outcomes<T: Eq + Hash + fmt::Display>(expected: HashSet<T>, generate: impl Fn() -> T) {
     let mut seen = HashSet::new();
-    // Let's give it 8x as many tries as we are expecting values.
-    let tries = expected.len() * 8;
+    // Let's give it sixteen times as many tries as we are expecting values.
+    let tries = expected.len() * 16;
     for _ in 0..tries {
         let val = generate();
         assert!(expected.contains(&val), "got an unexpected value: {val}");

tests/pass/issues/issue-3200-packed-field-offset.rs

@@ -0,0 +1,37 @@
+#![feature(layout_for_ptr)]
+use std::mem;
+
+#[repr(packed, C)]
+struct PackedSized {
+    f: u8,
+    d: [u32; 4],
+}
+
+#[repr(packed, C)]
+struct PackedUnsized {
+    f: u8,
+    d: [u32],
+}
+
+impl PackedSized {
+    fn unsize(&self) -> &PackedUnsized {
+        // We can't unsize via a generic type since then we get the error
+        // that packed structs with unsized tail don't work if the tail
+        // might need dropping.
+        let len = 4usize;
+        unsafe { mem::transmute((self, len)) }
+    }
+}
+
+fn main() {
+    unsafe {
+        let p = PackedSized { f: 0, d: [1, 2, 3, 4] };
+        let p = p.unsize() as *const PackedUnsized;
+        // Make sure the size computation does *not* think there is
+        // any padding in front of the `d` field.
+        assert_eq!(mem::size_of_val_raw(p), 1 + 4 * 4);
+        // And likewise for the offset computation.
+        let d = std::ptr::addr_of!((*p).d);
+        assert_eq!(d.cast::<u32>().read_unaligned(), 1);
+    }
+}

tests/pass/issues/issue-3200-packed2-field-offset.rs

@@ -0,0 +1,40 @@
+#![feature(layout_for_ptr)]
+use std::mem;
+
+#[repr(packed(4))]
+struct Slice([u32]);
+
+#[repr(packed(2), C)]
+struct PackedSized {
+    f: u8,
+    d: [u32; 4],
+}
+
+#[repr(packed(2), C)]
+struct PackedUnsized {
+    f: u8,
+    d: Slice,
+}
+
+impl PackedSized {
+    fn unsize(&self) -> &PackedUnsized {
+        // We can't unsize via a generic type since then we get the error
+        // that packed structs with unsized tail don't work if the tail
+        // might need dropping.
+        let len = 4usize;
+        unsafe { mem::transmute((self, len)) }
+    }
+}
+
+fn main() {
+    unsafe {
+        let p = PackedSized { f: 0, d: [1, 2, 3, 4] };
+        let p = p.unsize() as *const PackedUnsized;
+        // Make sure the size computation correctly adds exact 1 byte of padding
+        // in front of the `d` field.
+        assert_eq!(mem::size_of_val_raw(p), 1 + 1 + 4 * 4);
+        // And likewise for the offset computation.
+        let d = std::ptr::addr_of!((*p).d);
+        assert_eq!(d.cast::<u32>().read_unaligned(), 1);
+    }
+}