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use crate::bitset::BitSet;
use crate::ir;
use crate::isa::TargetIsa;
use alloc::vec::Vec;
type Num = u32;
const NUM_BITS: usize = core::mem::size_of::<Num>() * 8;
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "enable-serde", derive(serde::Deserialize, serde::Serialize))]
pub struct StackMap {
bitmap: Vec<BitSet<Num>>,
mapped_words: u32,
}
impl StackMap {
pub fn from_values(
args: &[ir::entities::Value],
func: &ir::Function,
isa: &dyn TargetIsa,
) -> Self {
let loc = &func.locations;
let mut live_ref_in_stack_slot = crate::HashSet::new();
for val in args {
if let Some(value_loc) = loc.get(*val) {
match *value_loc {
ir::ValueLoc::Stack(stack_slot) => {
live_ref_in_stack_slot.insert(stack_slot);
}
_ => {}
}
}
}
let stack = &func.stack_slots;
let info = func.stack_slots.layout_info.unwrap();
let map_size = (info.frame_size + info.inbound_args_size) as usize;
let word_size = isa.pointer_bytes() as usize;
let num_words = map_size / word_size;
let mut vec = alloc::vec::Vec::with_capacity(num_words);
vec.resize(num_words, false);
for (ss, ssd) in stack.iter() {
if !live_ref_in_stack_slot.contains(&ss)
|| ssd.kind == ir::stackslot::StackSlotKind::OutgoingArg
{
continue;
}
debug_assert!(ssd.size as usize == word_size);
let bytes_from_bottom = info.frame_size as i32 + ssd.offset.unwrap();
let words_from_bottom = (bytes_from_bottom as usize) / word_size;
vec[words_from_bottom] = true;
}
Self::from_slice(&vec)
}
pub fn from_slice(vec: &[bool]) -> Self {
let len = vec.len();
let num_word = len / NUM_BITS + (len % NUM_BITS != 0) as usize;
let mut bitmap = Vec::with_capacity(num_word);
for segment in vec.chunks(NUM_BITS) {
let mut curr_word = 0;
for (i, set) in segment.iter().enumerate() {
if *set {
curr_word |= 1 << i;
}
}
bitmap.push(BitSet(curr_word));
}
Self {
mapped_words: len as u32,
bitmap,
}
}
pub fn get_bit(&self, bit_index: usize) -> bool {
assert!(bit_index < NUM_BITS * self.bitmap.len());
let word_index = bit_index / NUM_BITS;
let word_offset = (bit_index % NUM_BITS) as u8;
self.bitmap[word_index].contains(word_offset)
}
pub fn as_slice(&self) -> &[BitSet<u32>] {
&self.bitmap
}
pub fn mapped_words(&self) -> u32 {
self.mapped_words
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn stack_maps() {
let vec: Vec<bool> = Vec::new();
assert!(StackMap::from_slice(&vec).bitmap.is_empty());
let mut vec: [bool; NUM_BITS] = Default::default();
let set_true_idx = [5, 7, 24, 31];
for &idx in &set_true_idx {
vec[idx] = true;
}
let mut vec = vec.to_vec();
assert_eq!(
vec![BitSet::<Num>(2164261024)],
StackMap::from_slice(&vec).bitmap
);
vec.push(false);
vec.push(true);
let res = StackMap::from_slice(&vec);
assert_eq!(
vec![BitSet::<Num>(2164261024), BitSet::<Num>(2)],
res.bitmap
);
assert!(res.get_bit(5));
assert!(res.get_bit(31));
assert!(res.get_bit(33));
assert!(!res.get_bit(1));
}
}