Struct HeapHeader 

#[repr(C)]
pub struct HeapHeader {
    pub refcount: AtomicU32,
    pub kind: u16,
    pub flags: u8,
    pub _pad: u8,
}

8-byte header for all v2 heap-allocated objects. Refcount at offset 0 for fastest access.

Fields

refcount: AtomicU32

Atomic reference count (offset 0, 4 bytes).

kind: u16

Object kind for GC/debug/serialization (offset 4, 2 bytes). Never used for hot-path type dispatch — compiled code knows the concrete type.

flags: u8

Bitfield flags: FLAG_MARKED, FLAG_PINNED, FLAG_READONLY (offset 6, 1 byte).

_pad: u8

Padding to 8 bytes (offset 7, 1 byte).

Implementations

impl HeapHeader

pub const OFFSET_REFCOUNT: usize = 0

Byte offset constants for JIT codegen.

pub const OFFSET_KIND: usize = 4

pub const OFFSET_FLAGS: usize = 6

pub fn new(kind: u16) -> Self

Create a new HeapHeader with the given kind, refcount initialized to 1.

pub fn kind(&self) -> u16

Get the kind field.

pub fn flags(&self) -> u8

Get the flags field.

pub fn has_flag(&self, flag: u8) -> bool

Check if a flag is set.

pub fn set_flag(&mut self, flag: u8)

Set a flag.

pub fn clear_flag(&mut self, flag: u8)

Clear a flag.

pub fn retain(&self)

Increment the reference count.

pub fn release(&self) -> bool

Decrement the reference count. Returns true if the count reached zero (caller must deallocate).

pub fn get_refcount(&self) -> u32

Get the current reference count (for debugging/testing).

Trait Implementations

impl Debug for HeapHeader

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.