forked from M-Labs/nac3
nac3core/typecheck: start implementing escape analysis
This commit is contained in:
parent
4f66bdeda9
commit
10c4544553
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@ -0,0 +1,276 @@
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use std::cell::RefCell;
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use std::collections::{HashMap, HashSet};
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use std::rc::Rc;
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use crate::typecheck::unification_table::{UnificationKey, UnificationTable};
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use itertools::Itertools;
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use nac3parser::ast::StrRef;
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// change this to enum, only local needs unification key
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pub type Lifetime = UnificationKey;
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#[derive(Copy, Debug, Clone, PartialEq, Eq, Hash)]
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pub enum LifetimeKind {
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// can be assigned to fields of anything
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// can be returned
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// lifetime of static values
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Global,
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// can only be assigned to fields of objects with local lifetime
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// can be returned
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// lifetime of parameters
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NonLocal,
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// can only be assigned to fields of objects with local lifetime
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// cannot be returned
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// lifetime of constructor return values
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Local,
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// can only be assigned to fields of objects with local lifetime
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// cannot be returned
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// lifetime of function return values
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Unknown,
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}
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impl std::ops::BitAnd for LifetimeKind {
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type Output = Self;
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fn bitand(self, other: Self) -> Self {
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use LifetimeKind::*;
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match (self, other) {
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(x, y) if x == y => x,
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(Global, NonLocal) | (NonLocal, Global) => NonLocal,
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_ => Unknown,
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}
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}
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}
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impl std::cmp::PartialOrd for LifetimeKind {
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fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
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use LifetimeKind::*;
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match (*self, *other) {
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(x, y) if x == y => Some(std::cmp::Ordering::Equal),
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(Local, _) | (_, Global) => Some(std::cmp::Ordering::Less),
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(_, Local) | (Global, _) => Some(std::cmp::Ordering::Greater),
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_ => None,
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}
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}
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}
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pub struct BlockLifetimeContext {
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mapping: Vec<(Option<Lifetime>, Lifetime)>,
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}
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impl BlockLifetimeContext {
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pub fn new() -> Self {
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BlockLifetimeContext { mapping: Vec::new() }
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}
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pub fn add_fresh(&mut self, lifetime: Lifetime) {
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self.mapping.push((None, lifetime));
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}
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}
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struct LifetimeEntry {
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kind: LifetimeKind,
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fields: RefCell<HashMap<StrRef, Lifetime>>,
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}
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pub struct LifetimeTable {
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table: UnificationTable<Rc<LifetimeEntry>>,
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cache: HashSet<(Lifetime, Lifetime)>,
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}
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impl LifetimeTable {
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pub fn new() -> Self {
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let mut zelf = Self { table: UnificationTable::new(), cache: Default::default() };
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zelf.table.new_key(Rc::new(LifetimeEntry {
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kind: LifetimeKind::Unknown,
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fields: Default::default(),
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}));
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zelf
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}
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pub fn add_lifetime(&mut self, kind: LifetimeKind) -> Lifetime {
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self.table.new_key(Rc::new(LifetimeEntry { kind, fields: Default::default() }))
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}
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pub fn unify(&mut self, a: Lifetime, b: Lifetime, ctx: &mut BlockLifetimeContext) {
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self.cache.clear();
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self.unify_impl(a, b, ctx);
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}
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fn get_scoped<const N: usize>(
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&mut self,
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mut lifetimes: [Lifetime; N],
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ctx: &mut BlockLifetimeContext,
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) -> [Lifetime; N] {
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for l in lifetimes.iter_mut() {
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let mut result = None;
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for (k, v) in ctx.mapping.iter() {
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if self.table.unioned(*v, *l) || k.map_or(false, |k| self.table.unioned(k, *l)) {
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// already fresh
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result = Some(*v);
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break;
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}
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}
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if let Some(result) = result {
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*l = result;
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} else {
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let lifetime = self.table.probe_value(*l).clone();
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*l = if lifetime.kind == LifetimeKind::Unknown {
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UnificationKey(0)
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} else {
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let k = self.table.new_key(lifetime);
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ctx.mapping.push((Some(*l), k));
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k
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}
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}
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}
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lifetimes
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}
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fn unify_impl(&mut self, a: Lifetime, b: Lifetime, ctx: &mut BlockLifetimeContext) {
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use LifetimeKind::*;
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let [a, b] = self.get_scoped([a, b], ctx);
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let a = self.table.get_representative(a);
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let b = self.table.get_representative(b);
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if a == b || self.cache.contains(&(a, b)) || self.cache.contains(&(b, a)) {
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return;
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}
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self.cache.insert((a, b));
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let v_a = self.table.probe_value(a).clone();
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let v_b = self.table.probe_value(b).clone();
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let result_kind = v_a.kind & v_b.kind;
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let fields = if result_kind == Local {
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// we only need to track fields lifetime for objects with local lifetime
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let fields = v_a.fields.clone();
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{
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let mut fields_ref = fields.borrow_mut();
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for (k, v) in v_b.fields.borrow().iter() {
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if let Some(old) = fields_ref.insert(k.clone(), *v) {
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self.unify_impl(old, *v, ctx);
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}
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}
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}
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fields
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} else {
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Default::default()
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};
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self.table.unify(a, b);
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self.table.set_value(a, Rc::new(LifetimeEntry { kind: result_kind, fields }));
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}
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pub fn get_field_lifetime(
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&mut self,
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lifetime: Lifetime,
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field: StrRef,
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ctx: &mut BlockLifetimeContext,
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) -> Lifetime {
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use LifetimeKind::*;
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let [lifetime] = self.get_scoped([lifetime], ctx);
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if let LifetimeEntry { kind: Local, fields } = &*self.table.probe_value(lifetime).clone() {
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if let Some(lifetime) = fields.borrow().get(&field) {
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*lifetime
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} else {
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// unknown lifetime
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// we can reuse this lifetime because it will never be unified to something else
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UnificationKey(0)
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}
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} else {
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lifetime
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}
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}
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pub fn set_field_lifetime(
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&mut self,
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obj: Lifetime,
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field: StrRef,
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lifetime: Lifetime,
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is_strong_update: bool,
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ctx: &mut BlockLifetimeContext,
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) -> Result<(), String> {
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let [obj, lifetime] = self.get_scoped([obj, lifetime], ctx);
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let obj_lifetime = self.table.probe_value(obj).clone();
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let field_lifetime = self.table.probe_value(lifetime).clone();
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if !(obj_lifetime.kind <= field_lifetime.kind) {
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return Err("lifetime error".to_string());
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}
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let mut fields = obj_lifetime.fields.borrow_mut();
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if is_strong_update {
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fields.insert(field, lifetime);
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} else {
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if let Some(old) = fields.insert(field, lifetime) {
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self.unify(old, lifetime, ctx);
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}
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}
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Ok(())
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}
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pub fn get_lifetime_kind(
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&mut self,
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lifetime: Lifetime,
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ctx: &mut BlockLifetimeContext,
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) -> LifetimeKind {
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let [lifetime] = self.get_scoped([lifetime], ctx);
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self.table.probe_value(lifetime).kind
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}
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pub fn set_function_params(&mut self, lifetime: Lifetime, ctx: &mut BlockLifetimeContext) {
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use LifetimeKind::*;
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// unify each field with global
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let [lifetime] = self.get_scoped([lifetime], ctx);
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let lifetime = self.table.probe_value(lifetime).clone();
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let mut worklist = lifetime.fields.borrow().values().copied().collect_vec();
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while let Some(item) = worklist.pop() {
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let [item] = self.get_scoped([item], ctx);
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let lifetime = self.table.probe_value(item).clone();
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if lifetime.kind == Unknown || lifetime.kind == Global {
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continue;
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}
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let fields = lifetime.fields.borrow().clone();
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for (_, v) in fields.iter() {
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worklist.push(*v);
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}
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self.table.set_value(
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item,
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Rc::new(LifetimeEntry {
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kind: lifetime.kind & Global,
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fields: RefCell::new(fields),
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}),
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);
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}
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}
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pub fn get_unknown_lifetime(&self) -> Lifetime {
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UnificationKey(0)
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}
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pub fn equiv(&mut self, a: Lifetime, b: Lifetime, ctx: &mut BlockLifetimeContext) -> bool {
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use LifetimeKind::Local;
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let [a, b] = self.get_scoped([a, b], ctx);
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if self.table.unioned(a, b) {
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return true;
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}
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let lifetime_a = self.table.probe_value(a).clone();
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let lifetime_b = self.table.probe_value(b).clone();
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if lifetime_a.kind == Local && lifetime_b.kind == Local {
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let fields_a = lifetime_a.fields.borrow();
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let fields_b = lifetime_b.fields.borrow();
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for (k, v) in fields_a.iter() {
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if fields_b.get(k).map(|v1| self.equiv(*v, *v1, ctx)) != Some(true) {
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return false;
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}
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}
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// they are just equivalent
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// this can avoid infinite recursion
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self.table.unify(a, b);
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true
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} else {
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lifetime_a.kind == lifetime_b.kind
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}
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}
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}
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@ -0,0 +1,317 @@
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use std::{collections::HashMap, sync::Arc};
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use nac3parser::ast::{Constant, Expr, ExprKind, StrRef};
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use crate::{
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symbol_resolver::SymbolResolver,
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toplevel::{TopLevelContext, TopLevelDef},
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};
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use self::lifetime::{BlockLifetimeContext, Lifetime, LifetimeTable};
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use super::{
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type_inferencer::PrimitiveStore,
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typedef::{Type, TypeEnum, Unifier},
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};
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pub mod lifetime;
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struct LifetimeContext<'a> {
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variable_mapping: HashMap<StrRef, (Lifetime, bool)>,
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scope_ctx: BlockLifetimeContext,
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lifetime_table: LifetimeTable,
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primitive_store: PrimitiveStore,
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unifier: &'a mut Unifier,
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resolver: Arc<dyn SymbolResolver + Send + Sync>,
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top_level: &'a TopLevelContext,
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}
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impl<'a> LifetimeContext<'a> {
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pub fn new(
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unifier: &'a mut Unifier,
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primitive_store: PrimitiveStore,
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resolver: Arc<dyn SymbolResolver + Send + Sync>,
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top_level: &'a TopLevelContext,
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) -> LifetimeContext<'a> {
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LifetimeContext {
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variable_mapping: HashMap::new(),
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scope_ctx: BlockLifetimeContext::new(),
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lifetime_table: LifetimeTable::new(),
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primitive_store,
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unifier,
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resolver,
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top_level,
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}
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}
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fn get_expr_lifetime(
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&mut self,
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expr: &Expr<Option<Type>>,
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) -> Result<Option<(Lifetime, bool)>, String> {
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let ty = expr.custom.unwrap();
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let is_primitive = self.unifier.unioned(ty, self.primitive_store.int32)
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|| self.unifier.unioned(ty, self.primitive_store.int64)
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|| self.unifier.unioned(ty, self.primitive_store.uint32)
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|| self.unifier.unioned(ty, self.primitive_store.uint64)
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|| self.unifier.unioned(ty, self.primitive_store.float)
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|| self.unifier.unioned(ty, self.primitive_store.bool)
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|| self.unifier.unioned(ty, self.primitive_store.none)
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|| self.unifier.unioned(ty, self.primitive_store.range);
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Ok(match &expr.node {
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ExprKind::Name { id, .. } => {
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if let Some(lifetime) = self.variable_mapping.get(id) {
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Some(*lifetime)
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} else {
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if is_primitive {
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None
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} else {
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let lifetime =
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self.lifetime_table.add_lifetime(lifetime::LifetimeKind::Global);
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self.variable_mapping.insert(id.clone(), (lifetime, false));
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Some((lifetime, false))
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}
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}
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}
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ExprKind::Attribute { value, attr, .. } => {
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if is_primitive {
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self.get_expr_lifetime(value)?;
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None
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} else {
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self.get_expr_lifetime(value)?.map(|lifetime| {
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(
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self.lifetime_table.get_field_lifetime(
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lifetime.0,
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*attr,
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&mut self.scope_ctx,
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),
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false, // not sure if it is strong update for now...
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)
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})
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}
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}
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ExprKind::Constant { .. } => {
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if is_primitive {
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None
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} else {
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Some((self.lifetime_table.add_lifetime(lifetime::LifetimeKind::Global), false))
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}
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}
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ExprKind::List { elts, .. } => {
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let elems =
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elts.iter()
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.map(|expr| self.get_expr_lifetime(expr))
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.collect::<Result<Vec<_>, _>>()?;
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let elem = elems.into_iter().reduce(|prev, next| {
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if prev.is_some() {
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self.lifetime_table.unify(
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prev.unwrap().0,
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next.unwrap().0,
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&mut self.scope_ctx,
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);
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}
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prev
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});
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let list_lifetime = self.lifetime_table.add_lifetime(lifetime::LifetimeKind::Local);
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if let Some(Some(elem)) = elem {
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self.lifetime_table
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.set_field_lifetime(
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list_lifetime,
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"elem".into(),
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elem.0,
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true,
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&mut self.scope_ctx,
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)
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.unwrap();
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}
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Some((list_lifetime, true))
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}
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ExprKind::Subscript { value, slice, .. } => {
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// value must be a list, so lifetime cannot be None
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let (value_lifetime, _) = self.get_expr_lifetime(value)?.unwrap();
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match &slice.node {
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ExprKind::Slice { lower, upper, step } => {
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for expr in [lower, upper, step].iter().filter_map(|x| x.as_ref()) {
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// account for side effects when computing the slice
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self.get_expr_lifetime(expr)?;
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}
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Some((
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self.lifetime_table.add_lifetime(lifetime::LifetimeKind::Local),
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true,
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))
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}
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ExprKind::Constant { value: Constant::Int(v), .. } => {
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if is_primitive {
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None
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} else if let TypeEnum::TList { .. } =
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&*self.unifier.get_ty(value.custom.unwrap())
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{
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Some((
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self.lifetime_table.get_field_lifetime(
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value_lifetime,
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"elem".into(),
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&mut self.scope_ctx,
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),
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false,
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))
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} else {
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// tuple
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Some((
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self.lifetime_table.get_field_lifetime(
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value_lifetime,
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format!("elem{}", v).into(),
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&mut self.scope_ctx,
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),
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false,
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))
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}
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}
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_ => {
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// account for side effects when computing the index
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self.get_expr_lifetime(slice)?;
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if is_primitive {
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None
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} else {
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Some((
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self.lifetime_table.get_field_lifetime(
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value_lifetime,
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"elem".into(),
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&mut self.scope_ctx,
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),
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false,
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))
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}
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}
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}
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}
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ExprKind::Tuple { elts, .. } => {
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let elems =
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elts.iter()
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.map(|expr| self.get_expr_lifetime(expr))
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.collect::<Result<Vec<_>, _>>()?;
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let tuple_lifetime =
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self.lifetime_table.add_lifetime(lifetime::LifetimeKind::Local);
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for (i, lifetime) in elems.into_iter().enumerate() {
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if let Some((lifetime, _)) = lifetime {
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self.lifetime_table
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.set_field_lifetime(
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tuple_lifetime,
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format!("elem{}", i).into(),
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lifetime,
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true,
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&mut self.scope_ctx,
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)
|
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.unwrap();
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}
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}
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Some((tuple_lifetime, true))
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}
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ExprKind::Call { func, args, keywords } => {
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let mut lifetimes = Vec::new();
|
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for arg in args.iter() {
|
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if let Some(lifetime) = self.get_expr_lifetime(arg)? {
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||||
lifetimes.push(lifetime.0);
|
||||
}
|
||||
}
|
||||
for keyword in keywords.iter() {
|
||||
if let Some(lifetime) = self.get_expr_lifetime(&keyword.node.value)? {
|
||||
lifetimes.push(lifetime.0);
|
||||
}
|
||||
}
|
||||
match &func.node {
|
||||
ExprKind::Name { id, .. } => {
|
||||
for lifetime in lifetimes.into_iter() {
|
||||
self.lifetime_table.set_function_params(lifetime, &mut self.scope_ctx);
|
||||
}
|
||||
if is_primitive {
|
||||
None
|
||||
} else {
|
||||
let id = self
|
||||
.resolver
|
||||
.get_identifier_def(*id)
|
||||
.map_err(|e| format!("{} (at {})", e, func.location))?;
|
||||
// constructors
|
||||
if let TopLevelDef::Class { .. } =
|
||||
&*self.top_level.definitions.read()[id.0].read()
|
||||
{
|
||||
Some((
|
||||
self.lifetime_table.add_lifetime(lifetime::LifetimeKind::Local),
|
||||
true,
|
||||
))
|
||||
} else {
|
||||
Some((self.lifetime_table.get_unknown_lifetime(), false))
|
||||
}
|
||||
}
|
||||
}
|
||||
ExprKind::Attribute { value, .. } => {
|
||||
if let Some(lifetime) = self.get_expr_lifetime(value)? {
|
||||
lifetimes.push(lifetime.0);
|
||||
}
|
||||
for lifetime in lifetimes.into_iter() {
|
||||
self.lifetime_table.set_function_params(lifetime, &mut self.scope_ctx);
|
||||
}
|
||||
if is_primitive {
|
||||
None
|
||||
} else {
|
||||
Some((self.lifetime_table.get_unknown_lifetime(), false))
|
||||
}
|
||||
}
|
||||
_ => unimplemented!(),
|
||||
}
|
||||
}
|
||||
ExprKind::BinOp { left, right, .. } => {
|
||||
let mut lifetimes = Vec::new();
|
||||
if let Some(l) = self.get_expr_lifetime(left)? {
|
||||
lifetimes.push(l.0);
|
||||
}
|
||||
if let Some(l) = self.get_expr_lifetime(right)? {
|
||||
lifetimes.push(l.0);
|
||||
}
|
||||
for lifetime in lifetimes.into_iter() {
|
||||
self.lifetime_table.set_function_params(lifetime, &mut self.scope_ctx);
|
||||
}
|
||||
if is_primitive {
|
||||
None
|
||||
} else {
|
||||
Some((self.lifetime_table.get_unknown_lifetime(), false))
|
||||
}
|
||||
}
|
||||
ExprKind::BoolOp { values, .. } => {
|
||||
for v in values {
|
||||
self.get_expr_lifetime(v)?;
|
||||
}
|
||||
None
|
||||
}
|
||||
ExprKind::UnaryOp { operand, .. } => {
|
||||
if let Some(l) = self.get_expr_lifetime(operand)? {
|
||||
self.lifetime_table.set_function_params(l.0, &mut self.scope_ctx);
|
||||
}
|
||||
if is_primitive {
|
||||
None
|
||||
} else {
|
||||
Some((self.lifetime_table.get_unknown_lifetime(), false))
|
||||
}
|
||||
}
|
||||
ExprKind::Compare { left, comparators, .. } => {
|
||||
let mut lifetimes = Vec::new();
|
||||
if let Some(l) = self.get_expr_lifetime(left)? {
|
||||
lifetimes.push(l.0);
|
||||
}
|
||||
for c in comparators {
|
||||
if let Some(l) = self.get_expr_lifetime(c)? {
|
||||
lifetimes.push(l.0);
|
||||
}
|
||||
}
|
||||
for lifetime in lifetimes.into_iter() {
|
||||
self.lifetime_table.set_function_params(lifetime, &mut self.scope_ctx);
|
||||
}
|
||||
// compare should give bool output, which does not have lifetime
|
||||
None
|
||||
}
|
||||
// TODO: listcomp, ifexpr
|
||||
_ => unimplemented!(),
|
||||
})
|
||||
|
||||
}
|
||||
}
|
||||
|
|
@ -4,3 +4,4 @@ pub mod type_error;
|
|||
pub mod type_inferencer;
|
||||
pub mod typedef;
|
||||
mod unification_table;
|
||||
pub mod escape_analysis;
|
||||
|
|
|
|||
|
|
@ -3,7 +3,7 @@ use std::rc::Rc;
|
|||
use itertools::izip;
|
||||
|
||||
#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
|
||||
pub struct UnificationKey(usize);
|
||||
pub struct UnificationKey(pub(crate) usize);
|
||||
|
||||
#[derive(Clone)]
|
||||
pub struct UnificationTable<V> {
|
||||
|
|
@ -44,6 +44,12 @@ impl<V> UnificationTable<V> {
|
|||
UnificationTable { parents: Vec::new(), ranks: Vec::new(), values: Vec::new(), log: Vec::new(), generation: 0 }
|
||||
}
|
||||
|
||||
fn log_action(&mut self, action: Action<V>) {
|
||||
if !self.log.is_empty() {
|
||||
self.log.push(action);
|
||||
}
|
||||
}
|
||||
|
||||
pub fn new_key(&mut self, v: V) -> UnificationKey {
|
||||
let index = self.parents.len();
|
||||
self.parents.push(index);
|
||||
|
|
@ -61,10 +67,10 @@ impl<V> UnificationTable<V> {
|
|||
if self.ranks[a] < self.ranks[b] {
|
||||
std::mem::swap(&mut a, &mut b);
|
||||
}
|
||||
self.log.push(Action::Parent { key: b, original_parent: self.parents[b] });
|
||||
self.log_action(Action::Parent { key: b, original_parent: self.parents[b] });
|
||||
self.parents[b] = a;
|
||||
if self.ranks[a] == self.ranks[b] {
|
||||
self.log.push(Action::Rank { key: a, original_rank: self.ranks[a] });
|
||||
self.log_action(Action::Rank { key: a, original_rank: self.ranks[a] });
|
||||
self.ranks[a] += 1;
|
||||
}
|
||||
}
|
||||
|
|
@ -88,7 +94,7 @@ impl<V> UnificationTable<V> {
|
|||
pub fn set_value(&mut self, a: UnificationKey, v: V) {
|
||||
let index = self.find(a);
|
||||
let original_value = self.values[index].replace(v);
|
||||
self.log.push(Action::Value { key: index, original_value });
|
||||
self.log_action(Action::Value { key: index, original_value });
|
||||
}
|
||||
|
||||
pub fn unioned(&mut self, a: UnificationKey, b: UnificationKey) -> bool {
|
||||
|
|
@ -106,7 +112,7 @@ impl<V> UnificationTable<V> {
|
|||
// a = parent.parent
|
||||
let a = self.parents[parent];
|
||||
// root.parent = parent.parent
|
||||
self.log.push(Action::Parent { key: root, original_parent: self.parents[root] });
|
||||
self.log_action(Action::Parent { key: root, original_parent: self.parents[root] });
|
||||
self.parents[root] = a;
|
||||
root = parent;
|
||||
// parent = root.parent
|
||||
|
|
|
|||
Loading…
Reference in New Issue