Struct wasmtime_environ::ConstExpr

pub struct ConstExpr { /* private fields */ }

A constant expression.

These are used to initialize globals, table elements, etc…

Implementations

impl ConstExpr

pub fn new(ops: impl IntoIterator<Item = ConstOp>) -> ConstExpr

Create a new const expression from the given opcodes.

Does not do any validation that the const expression is well-typed.

Panics if given zero opcodes.

pub fn from_wasmparser( expr: ConstExpr<'_>, ) -> Result<(ConstExpr, SmallVec<[FuncIndex; 1]>), WasmError>

Create a new const expression from a wasmparser const expression.

Returns the new const expression as well as the escaping function indices that appeared in ref.func instructions, if any.

pub fn ops(&self) -> &[ConstOp]

Get the opcodes that make up this const expression.

pub fn provably_nonzero_i32(&self) -> bool

Is this ConstExpr a provably nonzero integer value?

This must be conservative: if the expression might be zero, it must return false. It is always allowed to return false for some expression kind that we don’t support. However, if it returns true, the expression must be actually nonzero.

We use this for certain table optimizations that rely on knowing for sure that index 0 is not referenced.

Trait Implementations

impl Clone for ConstExpr

fn clone(&self) -> ConstExpr

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ConstExpr

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ConstExpr

fn deserialize<__D>( __deserializer: __D, ) -> Result<ConstExpr, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for ConstExpr

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

where __H: Hasher,

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 ConstExpr

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

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for ConstExpr

impl StructuralPartialEq for ConstExpr