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| // bun_alloc is the T0 foundation crate that bun_threading and bun_collections
// depend on; importing either to satisfy the disallowed-types lint would create
// a dependency cycle.
#![allow(clippy::disallowed_types)]
#![feature(arbitrary_self_types_pointers)]
#![feature(allocator_api)]
// `#[thread_local]` (vs the `thread_local!` macro) compiles to a bare
// `__thread` slot — single `mov reg, fs:[OFFSET]` access, no `LocalKey`
// `__getit()` wrapper, no lazy-init flag check, no dtor-registration probe.
// Used for the per-allocation hot-path TLS in `ast_alloc::AST_ALLOC`.
#![feature(thread_local)]
use core::fmt::Write as _;
use core::mem::{MaybeUninit, size_of};
use core::ptr::{NonNull, addr_of_mut};
use core::sync::atomic::{AtomicU16, AtomicU32, Ordering};
use std::collections::HashMap;
// ──────────────────────────────────────────────────────────────────────────
// Re-exports
// ──────────────────────────────────────────────────────────────────────────
pub use bun_mimalloc_sys::mimalloc;
pub mod c_thunks;
// ── Allocator vtable ───────────────────────────────────────────────────────
#[repr(transparent)]
#[derive(Clone, Copy, PartialEq, Eq)]
pub struct Alignment(pub u8); // log2 of byte alignment
impl Alignment {
#[inline]
pub(crate) const fn to_byte_units(self) -> usize {
1usize << self.0
}
#[inline]
pub(crate) const fn from_byte_units(b: usize) -> Self {
Self(b.trailing_zeros() as u8)
}
}
// ── `max_align_t` alignment ────────────────────────────────────────────────
// The `libc` crate does not expose `max_align_t` on every target Bun ships
// (missing on Windows MSVC and on FreeBSD aarch64), so those targets carry a
// local mirror of `max_align_t`. Remaining non-Windows targets keep
// `libc::max_align_t` (which carries `long double`, align 16 on x86_64/aarch64;
// the {f64,i64,*const ()} fallback would silently downgrade to 8).
#[cfg(windows)]
#[repr(C)]
struct MaxAlignT {
_f: f64,
_i: i64,
_p: *const (),
}
#[cfg(windows)]
pub(crate) const MAX_ALIGN_T: usize = core::mem::align_of::<MaxAlignT>();
// On AArch64
// AAPCS64 `long double` is IEEE binary128, 16-byte aligned. The `libc` crate
// only defines `max_align_t` for FreeBSD on x86_64, so hardcode the ABI value
// for the aarch64 port.
#[cfg(all(target_os = "freebsd", target_arch = "aarch64"))]
pub(crate) const MAX_ALIGN_T: usize = 16;
#[cfg(not(any(windows, all(target_os = "freebsd", target_arch = "aarch64"))))]
pub(crate) const MAX_ALIGN_T: usize = core::mem::align_of::<libc::max_align_t>();
pub struct AllocatorVTable {
pub alloc: unsafe fn(*mut core::ffi::c_void, usize, Alignment, usize) -> *mut u8,
pub resize: unsafe fn(*mut core::ffi::c_void, &mut [u8], Alignment, usize, usize) -> bool,
pub remap: unsafe fn(*mut core::ffi::c_void, &mut [u8], Alignment, usize, usize) -> *mut u8,
pub free: unsafe fn(*mut core::ffi::c_void, &mut [u8], Alignment, usize),
}
impl AllocatorVTable {
/// `alloc` impl that always fails. For vtables that only ever `free` an
/// externally-produced buffer (mmap region, plugin-owned memory, refcounted
/// foreign string) and never allocate or grow it.
pub(crate) const NO_ALLOC: unsafe fn(
*mut core::ffi::c_void,
usize,
Alignment,
usize,
) -> *mut u8 = |_, _, _, _| core::ptr::null_mut();
pub(crate) const NO_RESIZE: unsafe fn(
*mut core::ffi::c_void,
&mut [u8],
Alignment,
usize,
usize,
) -> bool = |_, _, _, _, _| false;
pub(crate) const NO_REMAP: unsafe fn(
*mut core::ffi::c_void,
&mut [u8],
Alignment,
usize,
usize,
) -> *mut u8 = |_, _, _, _, _| core::ptr::null_mut();
/// Build a "free-only" vtable: `alloc`/`resize`/`remap` all no-op/fail and
/// only `free` is meaningful. Each call site still gets its own `static`
/// (vtable address is an identity tag for `is_instance`).
pub const fn free_only(
free: unsafe fn(*mut core::ffi::c_void, &mut [u8], Alignment, usize),
) -> Self {
Self {
alloc: Self::NO_ALLOC,
resize: Self::NO_RESIZE,
remap: Self::NO_REMAP,
free,
}
}
}
/// Fat allocator handle (ptr + vtable). Distinct from the `Allocator` trait below.
#[derive(Clone, Copy)]
pub struct StdAllocator {
pub ptr: *mut core::ffi::c_void,
pub vtable: &'static AllocatorVTable,
}
// SAFETY: `ptr` is an opaque tag/context handle; the vtable is `&'static`.
// Thread-safety of dispatch is the implementor's concern (mimalloc is
// thread-safe).
unsafe impl Send for StdAllocator {}
// SAFETY: see the `Send` impl directly above.
unsafe impl Sync for StdAllocator {}
impl Default for StdAllocator {
/// The mimalloc-backed `c_allocator`.
#[inline]
fn default() -> Self {
basic::C_ALLOCATOR
}
}
impl StdAllocator {
#[inline]
pub(crate) fn raw_free(&self, buf: &mut [u8], alignment: Alignment, ra: usize) {
// SAFETY: vtable invariant — `free` callee respects the (ptr, buf, alignment, ra) contract.
unsafe { (self.vtable.free)(self.ptr, buf, alignment, ra) }
}
/// `raw_free` with `ret_addr = 0`, byte-aligned.
#[inline]
pub fn free(&self, bytes: &[u8]) {
if bytes.is_empty() {
return;
}
// SAFETY: `bytes` is reborrowed mutably only for the vtable signature; the
// callee treats it as opaque.
let buf =
unsafe { core::slice::from_raw_parts_mut(bytes.as_ptr().cast_mut(), bytes.len()) };
self.raw_free(buf, Alignment::from_byte_units(1), 0);
}
}
// PORTING.md §Allocators: AST crates thread an `Arena`; non-AST use Vec/Box
// (global mimalloc). `Arena` is the real per-heap `MimallocArena` — unlike
// `bumpalo::Bump`, it supports per-allocation free + realloc, so `ArenaVec`
// no longer leaks on grow.
pub use mimalloc_arena::MimallocArena;
pub type Arena = MimallocArena;
mod baby_vec;
pub use baby_vec::BabyVec;
/// Arena-backed `Vec` with `u32` length/capacity.
/// 24 B (vs 32 B for `Vec<T, &'a MimallocArena>`); the
/// allocator handle is kept inline for lifetime checking. Growth/free route
/// through `<&MimallocArena as Allocator>` (= `mi_heap_realloc_aligned` /
/// `mi_free`); reclaimed on arena `reset`/`Drop`.
pub type ArenaVec<'a, T> = BabyVec<'a, T>;
pub use mimalloc_arena::{ArenaString, ArenaVecExt};
/// `bumpalo::collections::Vec::from_iter_in` parity for [`ArenaVec`].
#[inline]
pub fn vec_from_iter_in<'a, T, I>(iter: I, arena: &'a MimallocArena) -> ArenaVec<'a, T>
where
I: IntoIterator<Item = T>,
{
let iter = iter.into_iter();
let (lo, _) = iter.size_hint();
let mut v = ArenaVec::with_capacity_in(lo, arena);
v.extend(iter);
v
}
/// Re-tag an [`ArenaVec`]'s allocator handle to `dst` without copying data.
///
/// Sound because `<&MimallocArena as Allocator>` is heap-agnostic on the
/// existing buffer:
/// - `deallocate` → `mi_free(ptr)`: looks up the owning heap from the pointer's
/// page metadata; works from any thread on any heap's allocation.
/// - `grow`/`shrink` → `mi_heap_realloc_aligned(dst, ptr, ..)`: returns `ptr`
/// in-place if it fits (read-only `mi_usable_size`), else allocs on `dst`,
/// `memcpy`s, then `mi_free(ptr)`.
///
/// The original arena is never `mi_heap_malloc`-ed from again via this `Vec`,
/// so the [`MimallocArena`] single-thread-alloc contract is preserved.
#[inline]
pub fn transfer_arena<'a, T>(v: &mut ArenaVec<'a, T>, dst: &'a MimallocArena) {
v.set_allocator(dst);
}
/// `bumpalo::format!` parity — `arena_format!(in arena, "...", ..)` →
/// [`ArenaString`].
#[macro_export]
macro_rules! arena_format {
(in $arena:expr, $($arg:tt)*) => {{
let mut __s = $crate::ArenaString::new_in($arena);
::core::fmt::Write::write_fmt(&mut __s, ::core::format_args!($($arg)*))
.expect("ArenaString::write_fmt is infallible");
__s
}};
}
/// `bun.use_mimalloc` — false under ASAN, where the global allocator is `std::alloc::System`.
pub const USE_MIMALLOC: bool = cfg!(not(bun_asan));
// ── Allocator-vtable modules: per-module disposition (PORTING.md §Allocators) ──
//
// MimallocArena → prefer `bun_alloc::Arena` (= bumpalo::Bump)
// MaxHeapAllocator → debug-only cap (single-allocation arena)
// heap_breakdown → macOS malloc_zone_* per-tag heaps (debug builds)
// basic → `impl GlobalAlloc for Mimalloc` above is the canonical impl
//
// LinuxMemFdAllocator, MimallocArena (the vtable impl)
// import bun_core/sys/runtime/collections and so live in
// `bun_runtime::allocators`; callers import from
// there directly.
//
#[path = "MaxHeapAllocator.rs"]
pub mod max_heap_allocator;
pub mod stack_fallback;
/// Raw alloc/free matching the `#[global_allocator]` (`mi_*` normally, libc under ASAN).
pub mod default_alloc {
use core::ffi::c_void;
#[inline]
pub fn malloc(size: usize) -> *mut c_void {
if cfg!(bun_asan) {
// SAFETY: `libc::malloc` has no input preconditions; null on failure.
unsafe { libc::malloc(size) }
} else {
crate::mimalloc::mi_malloc(size)
}
}
/// # Safety
/// `ptr` must be null or a live allocation from the default allocator.
#[inline]
pub unsafe fn realloc(ptr: *mut c_void, new_size: usize) -> *mut c_void {
if cfg!(bun_asan) {
// SAFETY: caller guarantees `ptr` is null or a live libc allocation
// (the default allocator under ASAN).
unsafe { libc::realloc(ptr, new_size) }
} else {
// SAFETY: caller guarantees `ptr` is null or a live mimalloc allocation.
unsafe { crate::mimalloc::mi_realloc(ptr, new_size) }
}
}
/// # Safety
/// `ptr` must be null or a live allocation from the default allocator.
#[inline]
pub unsafe fn free(ptr: *mut c_void) {
if cfg!(bun_asan) {
// SAFETY: caller guarantees `ptr` is null or a live libc allocation
// (the default allocator under ASAN).
unsafe { libc::free(ptr) }
} else {
// SAFETY: caller guarantees `ptr` is null or a live mimalloc allocation.
unsafe { crate::mimalloc::mi_free(ptr) }
}
}
/// # Safety
/// `ptr` must be null or a live allocation from the default allocator.
#[inline]
pub unsafe fn usable_size(ptr: *const c_void) -> usize {
if ptr.is_null() {
return 0;
}
// Under `bun_asan` the global allocator is `std::alloc::System`, so the
// size must come from libc, not mimalloc — and the symbol differs per
// OS (`malloc_usable_size` on Linux, `malloc_size` on macOS). `bun_asan`
// is only ever set on Linux or macOS, so the catch-all (non-asan, every
// `check-all` target including Windows) stays on mimalloc.
#[cfg(all(bun_asan, target_os = "linux"))]
return unsafe { libc::malloc_usable_size(ptr.cast_mut()) };
#[cfg(all(bun_asan, target_os = "macos"))]
return unsafe { libc::malloc_size(ptr) };
// SAFETY: caller guarantees `ptr` is a live mimalloc allocation (the
// non-null check above already handled null).
#[cfg(not(any(all(bun_asan, target_os = "linux"), all(bun_asan, target_os = "macos"))))]
return unsafe { crate::mimalloc::mi_usable_size(ptr) };
}
// The aligned variants are `#[cfg]`-split (not `if cfg!()`) because the
// posix_memalign/malloc_usable_size symbols don't exist on Windows.
#[cfg(not(bun_asan))]
#[inline]
pub(crate) fn malloc_aligned(size: usize, align: usize) -> *mut c_void {
crate::mimalloc::mi_malloc_auto_align(size, align)
}
#[cfg(bun_asan)]
#[inline]
pub(crate) fn malloc_aligned(size: usize, align: usize) -> *mut c_void {
if align <= crate::MAX_ALIGN_T {
return unsafe { libc::malloc(size) };
}
let mut p: *mut c_void = core::ptr::null_mut();
let align = align.max(core::mem::size_of::<*mut c_void>());
if unsafe { libc::posix_memalign(&mut p, align, size) } != 0 {
return core::ptr::null_mut();
}
p
}
/// # Safety
/// `ptr` must be null or a live allocation from the default allocator with the given `align`.
#[cfg(not(bun_asan))]
#[inline]
pub(crate) unsafe fn realloc_aligned(
ptr: *mut c_void,
new_size: usize,
align: usize,
) -> *mut c_void {
// SAFETY: caller guarantees `ptr` is null or a live mimalloc allocation
// with alignment `align`.
unsafe { crate::mimalloc::mi_realloc_aligned(ptr, new_size, align) }
}
/// # Safety
/// `ptr` must be null or a live allocation from the default allocator with the given `align`.
#[cfg(bun_asan)]
#[inline]
pub(crate) unsafe fn realloc_aligned(
ptr: *mut c_void,
new_size: usize,
align: usize,
) -> *mut c_void {
if align <= crate::MAX_ALIGN_T {
return unsafe { libc::realloc(ptr, new_size) };
}
let new_ptr = malloc_aligned(new_size, align);
if new_ptr.is_null() {
return core::ptr::null_mut();
}
if !ptr.is_null() {
unsafe {
let copy = usable_size(ptr).min(new_size);
core::ptr::copy_nonoverlapping(ptr.cast::<u8>(), new_ptr.cast::<u8>(), copy);
libc::free(ptr);
}
}
new_ptr
}
}
pub use max_heap_allocator::MaxHeapAllocator;
pub use stack_fallback::ArenaPtr;
#[path = "MimallocArena.rs"]
pub mod mimalloc_arena;
pub mod ast_alloc;
pub use ast_alloc::{AstAlloc, AstBox, AstVec, ast_box};
mod hashbrown_bridge;
/// Re-export so `bun_collections` can name the polyfill trait in
/// `StringHashMap`'s `A` bound without taking its own direct dep on
/// `allocator-api2`.
pub use allocator_api2::alloc::Allocator as HashbrownAllocator;
// ── tier-0 local primitives ───────────────────────────────────────────────
// Real, self-contained helpers used by the BSS containers below. These are the
// canonical tier-0 definitions, re-exported by higher tiers (`bun_paths::SEP_STR`,
// `bun_core::strings::trim_right`, `bun_core::strings::trim_right`).
/// `"\\"` on Windows, `"/"` elsewhere.
/// Canonical tier-0 definition; re-exported by `bun_paths::SEP_STR`.
pub const SEP_STR: &str = if cfg!(windows) { "\\" } else { "/" };
/// `b'\\'` on Windows, `b'/'` elsewhere.
/// Canonical tier-0 definition; re-exported by `bun_paths::SEP` / `bun_core::SEP`.
pub const SEP: u8 = if cfg!(windows) { b'\\' } else { b'/' };
/// Canonical tier-0 definition; re-exported by `bun_core::strings::trim_right`.
#[inline]
pub fn trim_right<'a>(s: &'a [u8], chars: &[u8]) -> &'a [u8] {
let mut end = s.len();
while end > 0 && chars.contains(&s[end - 1]) {
end -= 1;
}
&s[..end]
}
/// Canonical tier-0 definition; re-exported by `bun_core::strings::trim_left`.
#[inline]
pub fn trim_left<'a>(s: &'a [u8], chars: &[u8]) -> &'a [u8] {
let mut begin = 0usize;
while begin < s.len() && chars.contains(&s[begin]) {
begin += 1;
}
&s[begin..]
}
/// Strip `chars` from both ends.
/// Canonical tier-0 definition; re-exported by `bun_core::strings::trim`.
#[inline]
pub fn trim<'a>(s: &'a [u8], chars: &[u8]) -> &'a [u8] {
trim_right(trim_left(s, chars), chars)
}
// ─── ascii-lowercase helpers ──────────────────────────────────────────────
// Sunk from bun_core::strings so bun_alloc::BSSList::append_lower_case can call
// them without a dep cycle (bun_core → bun_alloc, not the reverse).
// `bun_core::strings` re-exports `copy_lowercase` and `ascii_lowercase_buf`.
/// ASCII-lowercase
/// `in_` into `out` (which must be at least `in_.len()`), returning the
/// written prefix. Memcpy-runs + per-uppercase-byte fixup; identical output
/// to a byte-at-a-time `to_ascii_lowercase` zip.
pub fn copy_lowercase<'a>(in_: &[u8], out: &'a mut [u8]) -> &'a [u8] {
let mut in_slice = in_;
// Reshaped for borrowck — track output offset instead of reslicing &mut.
let mut out_off: usize = 0;
'begin: loop {
for (i, &c) in in_slice.iter().enumerate() {
if let b'A'..=b'Z' = c {
out[out_off..out_off + i].copy_from_slice(&in_slice[0..i]);
out[out_off + i] = c.to_ascii_lowercase();
let end = i + 1;
in_slice = &in_slice[end..];
out_off += end;
continue 'begin;
}
}
out[out_off..out_off + in_slice.len()].copy_from_slice(in_slice);
break;
}
&out[0..in_.len()]
}
/// Lowercase `input` into a fresh `[u8; N]` stack buffer, returning
/// `Some((buf, input.len()))` or `None` if `input.len() > N`. The unused tail
/// of `buf` is zero-filled. Covers the ubiquitous "lowercase a short key into
/// a stack buffer, then look it up in a length-gated map" pattern.
#[inline]
pub fn ascii_lowercase_buf<const N: usize>(input: &[u8]) -> Option<([u8; N], usize)> {
if input.len() > N {
return None;
}
let mut buf = [0u8; N];
copy_lowercase(input, &mut buf[..input.len()]);
Some((buf, input.len()))
}
/// Wrap a raw allocator pointer in the `Result<NonNull<[u8]>, AllocError>`
/// shape `core::alloc::Allocator` wants. Null → `Err(AllocError)`. Generic
/// over the pointee so mimalloc's `*mut c_void` returns pass straight in.
#[inline(always)]
pub(crate) fn alloc_result<T>(
p: *mut T,
size: usize,
) -> core::result::Result<NonNull<[u8]>, core::alloc::AllocError> {
NonNull::new(p.cast::<u8>())
.map(|p| NonNull::slice_from_raw_parts(p, size))
.ok_or(core::alloc::AllocError)
}
/// Number of bytes the formatted args would produce.
///
/// Drives a discarding `fmt::Write` that only sums `s.len()` — no allocation,
/// no UTF-8 validation beyond what the formatter already did. Lives here in
/// T0 so higher tiers (`bun_core::fmt::count` re-exports this) and `bun_alloc`
/// itself can share the single implementation.
#[inline]
pub fn fmt_count(args: core::fmt::Arguments<'_>) -> usize {
struct Discarding(usize);
impl core::fmt::Write for Discarding {
#[inline]
fn write_str(&mut self, s: &str) -> core::fmt::Result {
self.0 += s.len();
Ok(())
}
}
let mut w = Discarding(0);
// Infallible: our `write_str` never errors.
let _ = core::fmt::write(&mut w, args);
w.0
}
/// `core::fmt::Write` adapter over a borrowed `&mut [u8]` — the engine behind
/// [`buf_print`] / [`buf_print_len`] (and `bun_core::fmt::buf_print_z`).
///
/// Lives at T0 so `bun_alloc` itself can use it (`BSSStringList::print`); T1
/// `bun_core::fmt` re-exports it and adds an `io::Write` impl for write-only
/// sites.
pub struct SliceCursor<'a> {
pub buf: &'a mut [u8],
pub at: usize,
}
impl<'a> SliceCursor<'a> {
#[inline]
pub fn new(buf: &'a mut [u8]) -> Self {
Self { buf, at: 0 }
}
}
impl core::fmt::Write for SliceCursor<'_> {
#[inline]
fn write_str(&mut self, s: &str) -> core::fmt::Result {
let bytes = s.as_bytes();
let end = self.at + bytes.len();
if end > self.buf.len() {
return Err(core::fmt::Error);
}
self.buf[self.at..end].copy_from_slice(bytes);
self.at = end;
Ok(())
}
}
/// Render the formatted args into `buf`, returning the written sub-slice.
/// Fails (`fmt::Error`) when `buf` is too short.
pub fn buf_print<'a>(
buf: &'a mut [u8],
args: core::fmt::Arguments<'_>,
) -> core::result::Result<&'a [u8], core::fmt::Error> {
let mut c = SliceCursor { buf, at: 0 };
core::fmt::write(&mut c, args)?;
let len = c.at;
Ok(&c.buf[..len])
}
} |
Bun passe à la version 1.4 et marque les esprits via une migration controversée de son code de Zig vers Rust
L'acquisition d'un outil d'infrastructure open source par une entreprise d'IA dont c'est l'usage interne constitue-t-elle une garantie de pérennité ou un risque de capture ? Où se situe le point de bascule ?
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