rust: alloc: remove our fork of the `alloc` crate

It is not used anymore as `VecExt` now provides the functionality we
depend on.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-5-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 0 insertions, 452 deletions

diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
deleted file mode 100644
index b1204f87227b..000000000000
--- a/rust/alloc/alloc.rs
+++ /dev/null
@@ -1,452 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0 OR MIT
-
-//! Memory allocation APIs
-
-#![stable(feature = "alloc_module", since = "1.28.0")]
-
-#[cfg(not(test))]
-use core::hint;
-
-#[cfg(not(test))]
-use core::ptr::{self, NonNull};
-
-#[stable(feature = "alloc_module", since = "1.28.0")]
-#[doc(inline)]
-pub use core::alloc::*;
-
-#[cfg(test)]
-mod tests;
-
-extern "Rust" {
-    // These are the magic symbols to call the global allocator. rustc generates
-    // them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute
-    // (the code expanding that attribute macro generates those functions), or to call
-    // the default implementations in std (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
-    // otherwise.
-    // The rustc fork of LLVM 14 and earlier also special-cases these function names to be able to optimize them
-    // like `malloc`, `realloc`, and `free`, respectively.
-    #[rustc_allocator]
-    #[rustc_nounwind]
-    fn __rust_alloc(size: usize, align: usize) -> *mut u8;
-    #[rustc_deallocator]
-    #[rustc_nounwind]
-    fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
-    #[rustc_reallocator]
-    #[rustc_nounwind]
-    fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
-    #[rustc_allocator_zeroed]
-    #[rustc_nounwind]
-    fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
-
-    static __rust_no_alloc_shim_is_unstable: u8;
-}
-
-/// The global memory allocator.
-///
-/// This type implements the [`Allocator`] trait by forwarding calls
-/// to the allocator registered with the `#[global_allocator]` attribute
-/// if there is one, or the `std` crate’s default.
-///
-/// Note: while this type is unstable, the functionality it provides can be
-/// accessed through the [free functions in `alloc`](self#functions).
-#[unstable(feature = "allocator_api", issue = "32838")]
-#[derive(Copy, Clone, Default, Debug)]
-#[cfg(not(test))]
-pub struct Global;
-
-#[cfg(test)]
-pub use std::alloc::Global;
-
-/// Allocate memory with the global allocator.
-///
-/// This function forwards calls to the [`GlobalAlloc::alloc`] method
-/// of the allocator registered with the `#[global_allocator]` attribute
-/// if there is one, or the `std` crate’s default.
-///
-/// This function is expected to be deprecated in favor of the `alloc` method
-/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
-///
-/// # Safety
-///
-/// See [`GlobalAlloc::alloc`].
-///
-/// # Examples
-///
-/// ```
-/// use std::alloc::{alloc, dealloc, handle_alloc_error, Layout};
-///
-/// unsafe {
-///     let layout = Layout::new::<u16>();
-///     let ptr = alloc(layout);
-///     if ptr.is_null() {
-///         handle_alloc_error(layout);
-///     }
-///
-///     *(ptr as *mut u16) = 42;
-///     assert_eq!(*(ptr as *mut u16), 42);
-///
-///     dealloc(ptr, layout);
-/// }
-/// ```
-#[stable(feature = "global_alloc", since = "1.28.0")]
-#[must_use = "losing the pointer will leak memory"]
-#[inline]
-pub unsafe fn alloc(layout: Layout) -> *mut u8 {
-    unsafe {
-        // Make sure we don't accidentally allow omitting the allocator shim in
-        // stable code until it is actually stabilized.
-        core::ptr::read_volatile(&__rust_no_alloc_shim_is_unstable);
-
-        __rust_alloc(layout.size(), layout.align())
-    }
-}
-
-/// Deallocate memory with the global allocator.
-///
-/// This function forwards calls to the [`GlobalAlloc::dealloc`] method
-/// of the allocator registered with the `#[global_allocator]` attribute
-/// if there is one, or the `std` crate’s default.
-///
-/// This function is expected to be deprecated in favor of the `dealloc` method
-/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
-///
-/// # Safety
-///
-/// See [`GlobalAlloc::dealloc`].
-#[stable(feature = "global_alloc", since = "1.28.0")]
-#[inline]
-pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
-    unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
-}
-
-/// Reallocate memory with the global allocator.
-///
-/// This function forwards calls to the [`GlobalAlloc::realloc`] method
-/// of the allocator registered with the `#[global_allocator]` attribute
-/// if there is one, or the `std` crate’s default.
-///
-/// This function is expected to be deprecated in favor of the `realloc` method
-/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
-///
-/// # Safety
-///
-/// See [`GlobalAlloc::realloc`].
-#[stable(feature = "global_alloc", since = "1.28.0")]
-#[must_use = "losing the pointer will leak memory"]
-#[inline]
-pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
-    unsafe { __rust_realloc(ptr, layout.size(), layout.align(), new_size) }
-}
-
-/// Allocate zero-initialized memory with the global allocator.
-///
-/// This function forwards calls to the [`GlobalAlloc::alloc_zeroed`] method
-/// of the allocator registered with the `#[global_allocator]` attribute
-/// if there is one, or the `std` crate’s default.
-///
-/// This function is expected to be deprecated in favor of the `alloc_zeroed` method
-/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
-///
-/// # Safety
-///
-/// See [`GlobalAlloc::alloc_zeroed`].
-///
-/// # Examples
-///
-/// ```
-/// use std::alloc::{alloc_zeroed, dealloc, Layout};
-///
-/// unsafe {
-///     let layout = Layout::new::<u16>();
-///     let ptr = alloc_zeroed(layout);
-///
-///     assert_eq!(*(ptr as *mut u16), 0);
-///
-///     dealloc(ptr, layout);
-/// }
-/// ```
-#[stable(feature = "global_alloc", since = "1.28.0")]
-#[must_use = "losing the pointer will leak memory"]
-#[inline]
-pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
-    unsafe { __rust_alloc_zeroed(layout.size(), layout.align()) }
-}
-
-#[cfg(not(test))]
-impl Global {
-    #[inline]
-    fn alloc_impl(&self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocError> {
-        match layout.size() {
-            0 => Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0)),
-            // SAFETY: `layout` is non-zero in size,
-            size => unsafe {
-                let raw_ptr = if zeroed { alloc_zeroed(layout) } else { alloc(layout) };
-                let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
-                Ok(NonNull::slice_from_raw_parts(ptr, size))
-            },
-        }
-    }
-
-    // SAFETY: Same as `Allocator::grow`
-    #[inline]
-    unsafe fn grow_impl(
-        &self,
-        ptr: NonNull<u8>,
-        old_layout: Layout,
-        new_layout: Layout,
-        zeroed: bool,
-    ) -> Result<NonNull<[u8]>, AllocError> {
-        debug_assert!(
-            new_layout.size() >= old_layout.size(),
-            "`new_layout.size()` must be greater than or equal to `old_layout.size()`"
-        );
-
-        match old_layout.size() {
-            0 => self.alloc_impl(new_layout, zeroed),
-
-            // SAFETY: `new_size` is non-zero as `old_size` is greater than or equal to `new_size`
-            // as required by safety conditions. Other conditions must be upheld by the caller
-            old_size if old_layout.align() == new_layout.align() => unsafe {
-                let new_size = new_layout.size();
-
-                // `realloc` probably checks for `new_size >= old_layout.size()` or something similar.
-                hint::assert_unchecked(new_size >= old_layout.size());
-
-                let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
-                let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
-                if zeroed {
-                    raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
-                }
-                Ok(NonNull::slice_from_raw_parts(ptr, new_size))
-            },
-
-            // SAFETY: because `new_layout.size()` must be greater than or equal to `old_size`,
-            // both the old and new memory allocation are valid for reads and writes for `old_size`
-            // bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
-            // `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
-            // for `dealloc` must be upheld by the caller.
-            old_size => unsafe {
-                let new_ptr = self.alloc_impl(new_layout, zeroed)?;
-                ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), old_size);
-                self.deallocate(ptr, old_layout);
-                Ok(new_ptr)
-            },
-        }
-    }
-}
-
-#[unstable(feature = "allocator_api", issue = "32838")]
-#[cfg(not(test))]
-unsafe impl Allocator for Global {
-    #[inline]
-    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
-        self.alloc_impl(layout, false)
-    }
-
-    #[inline]
-    fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
-        self.alloc_impl(layout, true)
-    }
-
-    #[inline]
-    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
-        if layout.size() != 0 {
-            // SAFETY: `layout` is non-zero in size,
-            // other conditions must be upheld by the caller
-            unsafe { dealloc(ptr.as_ptr(), layout) }
-        }
-    }
-
-    #[inline]
-    unsafe fn grow(
-        &self,
-        ptr: NonNull<u8>,
-        old_layout: Layout,
-        new_layout: Layout,
-    ) -> Result<NonNull<[u8]>, AllocError> {
-        // SAFETY: all conditions must be upheld by the caller
-        unsafe { self.grow_impl(ptr, old_layout, new_layout, false) }
-    }
-
-    #[inline]
-    unsafe fn grow_zeroed(
-        &self,
-        ptr: NonNull<u8>,
-        old_layout: Layout,
-        new_layout: Layout,
-    ) -> Result<NonNull<[u8]>, AllocError> {
-        // SAFETY: all conditions must be upheld by the caller
-        unsafe { self.grow_impl(ptr, old_layout, new_layout, true) }
-    }
-
-    #[inline]
-    unsafe fn shrink(
-        &self,
-        ptr: NonNull<u8>,
-        old_layout: Layout,
-        new_layout: Layout,
-    ) -> Result<NonNull<[u8]>, AllocError> {
-        debug_assert!(
-            new_layout.size() <= old_layout.size(),
-            "`new_layout.size()` must be smaller than or equal to `old_layout.size()`"
-        );
-
-        match new_layout.size() {
-            // SAFETY: conditions must be upheld by the caller
-            0 => unsafe {
-                self.deallocate(ptr, old_layout);
-                Ok(NonNull::slice_from_raw_parts(new_layout.dangling(), 0))
-            },
-
-            // SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
-            new_size if old_layout.align() == new_layout.align() => unsafe {
-                // `realloc` probably checks for `new_size <= old_layout.size()` or something similar.
-                hint::assert_unchecked(new_size <= old_layout.size());
-
-                let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
-                let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
-                Ok(NonNull::slice_from_raw_parts(ptr, new_size))
-            },
-
-            // SAFETY: because `new_size` must be smaller than or equal to `old_layout.size()`,
-            // both the old and new memory allocation are valid for reads and writes for `new_size`
-            // bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
-            // `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
-            // for `dealloc` must be upheld by the caller.
-            new_size => unsafe {
-                let new_ptr = self.allocate(new_layout)?;
-                ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), new_size);
-                self.deallocate(ptr, old_layout);
-                Ok(new_ptr)
-            },
-        }
-    }
-}
-
-/// The allocator for unique pointers.
-#[cfg(all(not(no_global_oom_handling), not(test)))]
-#[lang = "exchange_malloc"]
-#[inline]
-unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
-    let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
-    match Global.allocate(layout) {
-        Ok(ptr) => ptr.as_mut_ptr(),
-        Err(_) => handle_alloc_error(layout),
-    }
-}
-
-// # Allocation error handler
-
-#[cfg(not(no_global_oom_handling))]
-extern "Rust" {
-    // This is the magic symbol to call the global alloc error handler. rustc generates
-    // it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
-    // default implementations below (`__rdl_oom`) otherwise.
-    fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
-}
-
-/// Signal a memory allocation error.
-///
-/// Callers of memory allocation APIs wishing to cease execution
-/// in response to an allocation error are encouraged to call this function,
-/// rather than directly invoking [`panic!`] or similar.
-///
-/// This function is guaranteed to diverge (not return normally with a value), but depending on
-/// global configuration, it may either panic (resulting in unwinding or aborting as per
-/// configuration for all panics), or abort the process (with no unwinding).
-///
-/// The default behavior is:
-///
-///  * If the binary links against `std` (typically the case), then
-///   print a message to standard error and abort the process.
-///   This behavior can be replaced with [`set_alloc_error_hook`] and [`take_alloc_error_hook`].
-///   Future versions of Rust may panic by default instead.
-///
-/// * If the binary does not link against `std` (all of its crates are marked
-///   [`#![no_std]`][no_std]), then call [`panic!`] with a message.
-///   [The panic handler] applies as to any panic.
-///
-/// [`set_alloc_error_hook`]: ../../std/alloc/fn.set_alloc_error_hook.html
-/// [`take_alloc_error_hook`]: ../../std/alloc/fn.take_alloc_error_hook.html
-/// [The panic handler]: https://doc.rust-lang.org/reference/runtime.html#the-panic_handler-attribute
-/// [no_std]: https://doc.rust-lang.org/reference/names/preludes.html#the-no_std-attribute
-#[stable(feature = "global_alloc", since = "1.28.0")]
-#[rustc_const_unstable(feature = "const_alloc_error", issue = "92523")]
-#[cfg(all(not(no_global_oom_handling), not(test)))]
-#[cold]
-pub const fn handle_alloc_error(layout: Layout) -> ! {
-    const fn ct_error(_: Layout) -> ! {
-        panic!("allocation failed");
-    }
-
-    #[inline]
-    fn rt_error(layout: Layout) -> ! {
-        unsafe {
-            __rust_alloc_error_handler(layout.size(), layout.align());
-        }
-    }
-
-    #[cfg(not(feature = "panic_immediate_abort"))]
-    unsafe {
-        core::intrinsics::const_eval_select((layout,), ct_error, rt_error)
-    }
-
-    #[cfg(feature = "panic_immediate_abort")]
-    ct_error(layout)
-}
-
-// For alloc test `std::alloc::handle_alloc_error` can be used directly.
-#[cfg(all(not(no_global_oom_handling), test))]
-pub use std::alloc::handle_alloc_error;
-
-#[cfg(all(not(no_global_oom_handling), not(test)))]
-#[doc(hidden)]
-#[allow(unused_attributes)]
-#[unstable(feature = "alloc_internals", issue = "none")]
-pub mod __alloc_error_handler {
-    // called via generated `__rust_alloc_error_handler` if there is no
-    // `#[alloc_error_handler]`.
-    #[rustc_std_internal_symbol]
-    pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
-        extern "Rust" {
-            // This symbol is emitted by rustc next to __rust_alloc_error_handler.
-            // Its value depends on the -Zoom={panic,abort} compiler option.
-            static __rust_alloc_error_handler_should_panic: u8;
-        }
-
-        if unsafe { __rust_alloc_error_handler_should_panic != 0 } {
-            panic!("memory allocation of {size} bytes failed")
-        } else {
-            core::panicking::panic_nounwind_fmt(
-                format_args!("memory allocation of {size} bytes failed"),
-                /* force_no_backtrace */ false,
-            )
-        }
-    }
-}
-
-#[cfg(not(no_global_oom_handling))]
-/// Specialize clones into pre-allocated, uninitialized memory.
-/// Used by `Box::clone` and `Rc`/`Arc::make_mut`.
-pub(crate) trait WriteCloneIntoRaw: Sized {
-    unsafe fn write_clone_into_raw(&self, target: *mut Self);
-}
-
-#[cfg(not(no_global_oom_handling))]
-impl<T: Clone> WriteCloneIntoRaw for T {
-    #[inline]
-    default unsafe fn write_clone_into_raw(&self, target: *mut Self) {
-        // Having allocated *first* may allow the optimizer to create
-        // the cloned value in-place, skipping the local and move.
-        unsafe { target.write(self.clone()) };
-    }
-}
-
-#[cfg(not(no_global_oom_handling))]
-impl<T: Copy> WriteCloneIntoRaw for T {
-    #[inline]
-    unsafe fn write_clone_into_raw(&self, target: *mut Self) {
-        // We can always copy in-place, without ever involving a local value.
-        unsafe { target.copy_from_nonoverlapping(self, 1) };
-    }
-}