Struct rustc_passes::liveness::rwu_table::RWUTable

pub(super) struct RWUTable {
    live_nodes: usize,
    vars: usize,
    words: Vec<u8>,
    live_node_words: usize,
}

Conceptually, this is like a Vec<Vec<RWU>>. But the number of RWU’s can get very large, so it uses a more compact representation.

Fields

live_nodes: usize

Total number of live nodes.

vars: usize

Total number of variables.

words: Vec<u8>

A compressed representation of RWUs.

Each word represents 2 different RWUs packed together. Each packed RWU is stored in 4 bits: a reader bit, a writer bit, a used bit and a padding bit.

The data for each live node is contiguous and starts at a word boundary, so there might be an unused space left.

live_node_words: usize

Number of words per each live node.

Implementations

impl RWUTable

const RWU_READER: u8 = 1u8

const RWU_WRITER: u8 = 2u8

const RWU_USED: u8 = 4u8

const RWU_MASK: u8 = 15u8

const RWU_BITS: usize = 4usize

Size of packed RWU in bits.

const WORD_BITS: usize = 8usize

Size of a word in bits.

const WORD_RWU_COUNT: usize = 2usize

Number of packed RWUs that fit into a single word.

pub(super) fn new(live_nodes: usize, vars: usize) -> RWUTable

fn word_and_shift(&self, ln: LiveNode, var: Variable) -> (usize, u32)

fn pick2_rows_mut(&mut self, a: LiveNode, b: LiveNode) -> (&mut [u8], &mut [u8])

pub(super) fn copy(&mut self, dst: LiveNode, src: LiveNode)

pub(super) fn union(&mut self, dst: LiveNode, src: LiveNode) -> bool

Sets dst to the union of dst and src, returns true if dst was changed.

pub(super) fn get_reader(&self, ln: LiveNode, var: Variable) -> bool

pub(super) fn get_writer(&self, ln: LiveNode, var: Variable) -> bool

pub(super) fn get_used(&self, ln: LiveNode, var: Variable) -> bool

pub(super) fn get(&self, ln: LiveNode, var: Variable) -> RWU

pub(super) fn set(&mut self, ln: LiveNode, var: Variable, rwu: RWU)

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 48 bytes