Enum ArgumentPurpose

pub enum ArgumentPurpose {
    Normal,
    StructArgument(u32),
    StructReturn,
    VMContext,
}

The special purpose of a function argument.

Function arguments and return values are used to pass user program values between functions, but they are also used to represent special registers with significance to the ABI such as frame pointers and callee-saved registers.

The argument purpose is used to indicate any special meaning of an argument or return value.

Variants

Normal

A normal user program value passed to or from a function.

StructArgument(u32)

A C struct passed as argument.

Note that this should only be used when interacting with code following a C ABI which is expecting a struct passed by value.

Tuple Fields

0: u32

The size, in bytes, of the struct.

StructReturn

Struct return pointer.

When a function needs to return more data than will fit in registers, the caller passes a pointer to a memory location where the return value can be written. In some ABIs, this struct return pointer is passed in a specific register.

This argument kind can also appear as a return value for ABIs that require a function with a StructReturn pointer argument to also return that pointer in a register.

VMContext

A VM context pointer.

This is a pointer to a context struct containing details about the current sandbox. It is used as a base pointer for vmctx global values.

Trait Implementations

impl Clone for ArgumentPurpose

fn clone(&self) -> ArgumentPurpose

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ArgumentPurpose

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

Formats the value using the given formatter.

impl Display for ArgumentPurpose

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

Formats the value using the given formatter.

impl FromStr for ArgumentPurpose

type Err = ()

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, ()>

Parses a string s to return a value of this type.

impl Hash for ArgumentPurpose

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for ArgumentPurpose

fn eq(&self, other: &ArgumentPurpose) -> 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 ArgumentPurpose

impl Eq for ArgumentPurpose

impl StructuralPartialEq for ArgumentPurpose