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globalize ALIGN_CELL/ALIGN, fix compute_pstr_size

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This commit is contained in:
Mark Thom
2025-02-24 19:54:35 -08:00
committed by Mark Thom
parent 15f1320d05
commit 3c85ef2724
1 changed files with 7 additions and 16 deletions
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23
src/machine/heap.rs
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@@ -15,6 +15,8 @@ use super::MachineState;
use bitvec::prelude::*;
use bitvec::slice::BitSlice;
const ALIGN: usize = Heap::heap_cell_alignment();
#[derive(Debug)]
pub struct Heap {
inner: InnerHeap,
@@ -94,10 +96,9 @@ static RESOURCE_ERROR_OFFSET_INIT: Once = Once::new();
fn scan_slice_to_str(orig_ptr: *const u8, pstr_vec: &BitSlice) -> (&str, usize) {
unsafe {
debug_assert_eq!(pstr_vec[0], true);
const ALIGN_CELL: usize = Heap::heap_cell_alignment();
let tail_cell_offset = pstr_vec[0..].first_zero().unwrap();
let offset = (ALIGN_CELL - orig_ptr.align_offset(ALIGN_CELL)) % 8;
let offset = (ALIGN - orig_ptr.align_offset(ALIGN)) % 8;
let buf_len = heap_index!(tail_cell_offset) - offset;
let slice = std::slice::from_raw_parts(orig_ptr, buf_len);
@@ -342,8 +343,6 @@ impl<'a> ReservedHeapSection<'a> {
let cells_written;
let str_byte_len = src.len();
const ALIGN_CELL: usize = Heap::heap_cell_alignment();
unsafe {
ptr::copy_nonoverlapping(
src.as_ptr(),
@@ -477,8 +476,6 @@ impl<'a> Index<usize> for ReservedHeapSection<'a> {
/// with zeroes, such that `chunk_len + pstr_sentinel_length(chunk_len)` is a
/// multiple of `Heap::heap_cell_alignement()`.
fn pstr_sentinel_length(chunk_len: usize) -> usize {
const ALIGN: usize = Heap::heap_cell_alignment();
let res = chunk_len.next_multiple_of(ALIGN) - chunk_len;
// No bytes available in last chunk
@@ -924,8 +921,7 @@ impl Heap {
// takes a byte offset into the Heap ptr.
#[inline(always)]
pub(crate) const fn neighboring_cell_offset(offset: usize) -> usize {
const ALIGN_CELL: usize = Heap::heap_cell_alignment();
cell_index!((offset & !(ALIGN_CELL - 1)) + ALIGN_CELL)
cell_index!((offset & !(ALIGN - 1)) + ALIGN)
}
#[inline]
@@ -978,10 +974,7 @@ impl Heap {
let (s, tail_loc) = self.scan_slice_to_str(pstr_loc);
let s_len = s.len();
const ALIGN_CELL: usize = Heap::heap_cell_alignment();
let align_offset = pstr_sentinel_length(s_len);
let copy_size = s_len + align_offset;
unsafe {
@@ -1044,10 +1037,8 @@ impl Heap {
}
/// Returns the number of bytes needed to store `src` as a `PStr`.
/// Assumes the string will be allocated on a ALIGN_CELL-byte boundary.
/// Assumes the string will be allocated on a ALIGN-byte boundary.
pub(crate) fn compute_pstr_size(src: &str) -> usize {
const ALIGN_CELL: usize = Heap::heap_cell_alignment();
if src.is_empty() {
return 0;
}
@@ -1066,9 +1057,9 @@ impl Heap {
null_idx += 1;
}
byte_size += null_idx.next_multiple_of(ALIGN_CELL);
byte_size += null_idx + pstr_sentinel_length(null_idx);
if (null_idx + 1) % ALIGN_CELL == 0 {
if (null_idx + 1) % ALIGN == 0 {
byte_size += 2 * mem::size_of::<HeapCellValue>();
} else {
byte_size += mem::size_of::<HeapCellValue>();