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fix(allocator): fix FixedSizeAllocator pointer maths #12299

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Merged
graphite-app merged 1 commit into from
Jul 15, 2025
Merged

fix(allocator): fix FixedSizeAllocator pointer maths #12299

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3 changes: 2 additions & 1 deletion crates/oxc_allocator/src/fixed_size.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ use crate::{
};

const TWO_GIB: usize = 1 << 31;
const FOUR_GIB: usize = 1 << 32;

// What we ideally want is an allocation 2 GiB in size, aligned on 4 GiB.
// But system allocator on Mac OS refuses allocations with 4 GiB alignment.
Expand Down Expand Up @@ -68,7 +69,7 @@ impl FixedSizeAllocator {
// SAFETY: `offset` is either 0 or `TWO_GIB`.
// We allocated 4 GiB of memory, so adding `offset` to `alloc_ptr` is in bounds.
let chunk_ptr = unsafe {
let offset = alloc_ptr.as_ptr() as usize % ALLOC_SIZE;
let offset = alloc_ptr.as_ptr() as usize % FOUR_GIB;
alloc_ptr.add(offset)
};

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