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-rw-r--r--rust/alloc/alloc.rs55
1 files changed, 30 insertions, 25 deletions
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index ca224a541770..acf22d45e6f2 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -22,21 +22,24 @@ use core::marker::Destruct;
mod tests;
extern "Rust" {
- // These are the magic symbols to call the global allocator. rustc generates
+ // 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 libstd (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
+ // the default implementations in std (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
// otherwise.
- // The rustc fork of LLVM also special-cases these function names to be able to optimize them
+ // 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_allocator_nounwind]
+ #[rustc_nounwind]
fn __rust_alloc(size: usize, align: usize) -> *mut u8;
- #[rustc_allocator_nounwind]
+ #[rustc_deallocator]
+ #[rustc_nounwind]
fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
- #[rustc_allocator_nounwind]
+ #[rustc_reallocator]
+ #[rustc_nounwind]
fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
- #[rustc_allocator_nounwind]
+ #[rustc_allocator_zeroed]
+ #[rustc_nounwind]
fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
}
@@ -72,11 +75,14 @@ pub use std::alloc::Global;
/// # Examples
///
/// ```
-/// use std::alloc::{alloc, dealloc, Layout};
+/// 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);
@@ -349,7 +355,7 @@ pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Dest
#[cfg(not(no_global_oom_handling))]
extern "Rust" {
- // This is the magic symbol to call the global alloc error handler. rustc generates
+ // 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) -> !;
@@ -394,25 +400,24 @@ pub use std::alloc::handle_alloc_error;
#[allow(unused_attributes)]
#[unstable(feature = "alloc_internals", issue = "none")]
pub mod __alloc_error_handler {
- use crate::alloc::Layout;
-
- // called via generated `__rust_alloc_error_handler`
-
- // if there is no `#[alloc_error_handler]`
+ // called via generated `__rust_alloc_error_handler` if there is no
+ // `#[alloc_error_handler]`.
#[rustc_std_internal_symbol]
- pub unsafe extern "C-unwind" fn __rdl_oom(size: usize, _align: usize) -> ! {
- panic!("memory allocation of {size} bytes failed")
- }
-
- // if there is an `#[alloc_error_handler]`
- #[rustc_std_internal_symbol]
- pub unsafe extern "C-unwind" fn __rg_oom(size: usize, align: usize) -> ! {
- let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
+ pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
extern "Rust" {
- #[lang = "oom"]
- fn oom_impl(layout: Layout) -> !;
+ // 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;
+ }
+
+ #[allow(unused_unsafe)]
+ 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"
+ ))
}
- unsafe { oom_impl(layout) }
}
}