Struct CallIndirectHost

pub struct CallIndirectHost {
    pub id: u8,
}

A special opcode to halt interpreter execution and yield control back to the host.

This opcode results in DoneReason::CallIndirectHost where the id here is shepherded along to the embedder. It’s up to the embedder to determine what to do with the id and the current state of registers and the stack.

In Wasmtime this is used to implement interpreter-to-host calls. This is modeled as a call instruction where the first parameter is the native function pointer to invoke and all remaining parameters for the native function are in following parameter positions (e.g. x1, x2, …). The results of the host call are then store in x0.

Handling this in Wasmtime is done through a “relocation” which is resolved at link-time when raw bytecode from Cranelift is assembled into the final object that Wasmtime will interpret.

Fields

id: u8

Implementations

impl CallIndirectHost

pub fn encode<E>(&self, into: &mut E)

where E: Extend<u8>,

Available on crate feature encode only.

Encode this CallIndirectHost op into the given sink.

Trait Implementations

impl<'arbitrary> Arbitrary<'arbitrary> for CallIndirectHost

fn arbitrary(u: &mut Unstructured<'arbitrary>) -> Result<Self>

Generate an arbitrary value of Self from the given unstructured data.

fn arbitrary_take_rest(u: Unstructured<'arbitrary>) -> Result<Self>

Generate an arbitrary value of Self from the entirety of the given unstructured data.

fn size_hint(depth: usize) -> (usize, Option<usize>)

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

fn try_size_hint( depth: usize, ) -> Result<(usize, Option<usize>), MaxRecursionReached>

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

impl Clone for CallIndirectHost

fn clone(&self) -> CallIndirectHost

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CallIndirectHost

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

Formats the value using the given formatter.

impl Encode for CallIndirectHost

Available on crate feature encode only.

const WIDTH: u8 = 4u8

The encoded width of this instruction.

fn encode<E>(&self, sink: &mut E)

where E: Extend<u8>,

Encodes this operand or instruction into the provided sink.

impl From<CallIndirectHost> for ExtendedOp

fn from(op: CallIndirectHost) -> Self

Converts to this type from the input type.

impl From<CallIndirectHost> for Op

fn from(op: CallIndirectHost) -> Self

Converts to this type from the input type.

impl PartialEq for CallIndirectHost

fn eq(&self, other: &CallIndirectHost) -> 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 Copy for CallIndirectHost

impl Eq for CallIndirectHost

impl StructuralPartialEq for CallIndirectHost