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add as_ptr to trait AllocBytes, fix 2 impls; add pub fn get_bytes_unchecked_raw in allocation.rs; add pub fn get_alloc_bytes_unchecked_raw[_mut] in memory.rs

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This commit is contained in:
Strophox 2024-06-21 12:47:04 +02:00
parent e32ea4822b
commit b512bf6f77
3 changed files with 44 additions and 3 deletions
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26
compiler/rustc_middle/src/mir/interpret/allocation.rs
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@ -40,9 +40,16 @@ pub trait AllocBytes: Clone + fmt::Debug + Deref<Target = [u8]> + DerefMut<Targe
/// Gives direct access to the raw underlying storage.
///
/// Crucially this pointer is compatible with:
/// - other pointers retunred by this method, and
/// - other pointers returned by this method, and
/// - references returned from `deref()`, as long as there was no write.
fn as_mut_ptr(&mut self) -> *mut u8;
/// Gives direct access to the raw underlying storage.
///
/// Crucially this pointer is compatible with:
/// - other pointers returned by this method, and
/// - references returned from `deref()`, as long as there was no write.
fn as_ptr(&self) -> *const u8;
}
/// Default `bytes` for `Allocation` is a `Box<u8>`.
@ -62,6 +69,11 @@ impl AllocBytes for Box<[u8]> {
// Carefully avoiding any intermediate references.
ptr::addr_of_mut!(**self).cast()
}
fn as_ptr(&self) -> *const u8 {
// Carefully avoiding any intermediate references.
ptr::addr_of!(**self).cast()
}
}
/// This type represents an Allocation in the Miri/CTFE core engine.
@ -490,19 +502,27 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
self.provenance.clear(range, cx)?;
assert!(range.end().bytes_usize() <= self.bytes.len()); // need to do our own bounds-check
// Cruciall, we go via `AllocBytes::as_mut_ptr`, not `AllocBytes::deref_mut`.
// Crucially, we go via `AllocBytes::as_mut_ptr`, not `AllocBytes::deref_mut`.
let begin_ptr = self.bytes.as_mut_ptr().wrapping_add(range.start.bytes_usize());
let len = range.end().bytes_usize() - range.start.bytes_usize();
Ok(ptr::slice_from_raw_parts_mut(begin_ptr, len))
}
/// This gives direct mutable access to the entire buffer, just exposing their internal state
/// without reseting anything. Directly exposes `AllocBytes::as_mut_ptr`. Only works if
/// without resetting anything. Directly exposes `AllocBytes::as_mut_ptr`. Only works if
/// `OFFSET_IS_ADDR` is true.
pub fn get_bytes_unchecked_raw_mut(&mut self) -> *mut u8 {
assert!(Prov::OFFSET_IS_ADDR);
self.bytes.as_mut_ptr()
}
/// This gives direct immutable access to the entire buffer, just exposing their internal state
/// without resetting anything. Directly exposes `AllocBytes::as_ptr`. Only works if
/// `OFFSET_IS_ADDR` is true.
pub fn get_bytes_unchecked_raw(&self) -> *const u8 {
assert!(Prov::OFFSET_IS_ADDR);
self.bytes.as_ptr()
}
}
/// Reading and writing.