Struct FrameDescriptor 

pub struct FrameDescriptor {
    pub slots: Vec<SlotKind>,
    pub return_kind: SlotKind,
}

Typed frame layout metadata.

A FrameDescriptor describes the storage layout for every local slot (parameters + locals) in a single function or top-level frame. The JIT and VM use this to allocate registers / stack space with correct widths and to skip NaN-boxing for slots whose type is statically known.

This is the canonical replacement for the loose Vec<StorageHint> arrays that were previously threaded through BytecodeProgram and Function.

Fields

slots: Vec<SlotKind>

One entry per local slot (index 0 = first param or local). A Boxed entry means the slot stores a generic NaN-boxed value.

return_kind: SlotKind

Return type kind for the function.

When present and not Unknown, the JIT boundary ABI uses this to unmarshal the return value from JIT-compiled code back into the correct ValueWord representation.

Implementations

impl FrameDescriptor

pub fn new() -> Self

Create an empty descriptor (all slots will be Boxed by default).

pub fn with_unknown_slots(n: usize) -> Self

Create a descriptor with n slots, all initialised to SlotKind::Unknown.

pub fn from_slots(slots: Vec<SlotKind>) -> Self

Build a descriptor from an existing Vec<SlotKind> (or Vec<StorageHint>).

pub fn len(&self) -> usize

Number of slots described.

pub fn is_empty(&self) -> bool

Whether the descriptor is empty.

pub fn slot(&self, index: usize) -> SlotKind

Get the kind of a specific slot. Returns Boxed for out-of-range indices.

pub fn is_all_unknown(&self) -> bool

Returns true if every slot is Unknown (i.e. no specialization).

Trait Implementations

impl Clone for FrameDescriptor

fn clone(&self) -> FrameDescriptor

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FrameDescriptor

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

Formats the value using the given formatter.

impl Default for FrameDescriptor

fn default() -> FrameDescriptor

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for FrameDescriptor

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for FrameDescriptor

fn eq(&self, other: &FrameDescriptor) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for FrameDescriptor

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for FrameDescriptor

impl StructuralPartialEq for FrameDescriptor