Struct ConstPropState 

pub struct ConstPropState {
    pub values: HashMap<String, Option<i64>>,
}

A simple constant propagation state: maps variables to known constant values or marks them as non-constant (⊤).

Fields

values: HashMap<String, Option<i64>>

None = unknown/non-constant (⊤); Some(v) = definitely v.

Implementations

impl ConstPropState

pub fn new() -> Self

Create a new state.

pub fn set_const(&mut self, var: impl Into<String>, val: i64)

Define a variable as a known constant.

pub fn set_top(&mut self, var: impl Into<String>)

Mark a variable as non-constant.

pub fn get(&self, var: &str) -> Option<i64>

Get the constant value of a variable, if known.

pub fn join(&self, other: &ConstPropState) -> ConstPropState

Join two states (meet of constant info: agree ⇒ keep, disagree ⇒ top).

pub fn fold_add(&self, lhs: &str, rhs: &str) -> Option<i64>

Attempt constant folding of a binary add expression.

Trait Implementations

impl Clone for ConstPropState

fn clone(&self) -> ConstPropState

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ConstPropState

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

Formats the value using the given formatter.

impl Default for ConstPropState

fn default() -> ConstPropState

Returns the “default value” for a type.