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make LiveBorrows Clone
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@b-naber
b-naber committed Jun 29, 2023
1 parent 0b39afe commit 2208981
Showing 1 changed file with 56 additions and 55 deletions.
111 changes: 56 additions & 55 deletions compiler/rustc_mir_dataflow/src/impls/live_borrows.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -778,9 +778,7 @@ impl<'a, 'tcx> Visitor<'tcx> for BorrowDependencies<'a, 'tcx> {
Rvalue::Ref(_, borrow_kind, borrowed_place) => {
let mutbl = match borrow_kind {
BorrowKind::Mut { .. } => Mutability::Mut,
BorrowKind::Shallow | BorrowKind::Shared | BorrowKind::Unique => {
Mutability::Not
}
BorrowKind::Shallow | BorrowKind::Shared => Mutability::Not,
};

self.handle_rvalue_ref_or_ptr(borrowed_place, mutbl)
Expand Down Expand Up @@ -923,8 +921,8 @@ where
MaybeBorrowedLocals,
&'a Results<'tcx, MaybeBorrowedLocals>,
>,
dep_graph: BorrowDepGraph,
) -> Self {
let dep_graph = &borrows_analysis_results.analysis.borrow_deps.dep_graph;
let borrowed_local_to_locals_to_keep_alive = Self::get_locals_to_keep_alive_map(dep_graph);
Self {
borrows_analysis_results,
Expand All @@ -938,14 +936,14 @@ where
/// Uses the dependency graph to find all locals that we need to keep live for a given
/// `Node` (or more specically the `Local` corresponding to that `Node`).
#[instrument(skip(dep_graph), level = "debug")]
fn get_locals_to_keep_alive_map<'b>(
dep_graph: &'b BorrowDepGraph,
fn get_locals_to_keep_alive_map(
dep_graph: BorrowDepGraph,
) -> FxHashMap<Local, FxHashSet<Local>> {
let mut borrows_to_locals: FxHashMap<Local, FxHashSet<Local>> = Default::default();
let mut memoization_map: FxHashMap<NodeIndex, FxHashSet<Local>> = Default::default();

// create SCCs for dependency graph and map each local to its SCC.
let sccs: Sccs<NodeIndex, NodeIndex> = Sccs::new(dep_graph);
let sccs: Sccs<NodeIndex, NodeIndex> = Sccs::new(&dep_graph);

// Contains the Locals to keep alive for each scc.
let mut scc_to_locals_to_keep_alive: FxHashMap<NodeIndex, FxHashSet<Local>> =
Expand Down Expand Up @@ -1096,11 +1094,28 @@ pub fn get_borrowed_locals_results<'a, 'mir, 'tcx>(
}
}

let live_borrows = LiveBorrows::new(body, tcx, borrow_deps);
let results =
let reborrows_map = borrow_deps.reborrows_map;
let local_to_nodekind = borrow_deps
.dep_graph
.all_nodes()
.iter()
.map(|node| {
let nodekind = node.data;
let local = nodekind.get_local();

(local, nodekind)
})
.collect::<FxHashMap<Local, NodeKind>>();

let live_borrows = LiveBorrows::new(body, tcx, local_to_nodekind, reborrows_map);
let live_borrows_results =
live_borrows.into_engine(tcx, body).pass_name("borrowed_locals").iterate_to_fixpoint();

BorrowedLocalsResults::new(results, maybe_borrowed_locals_cursor)
BorrowedLocalsResults::new(
live_borrows_results,
maybe_borrowed_locals_cursor,
borrow_deps.dep_graph,
)
}

/// The `ResultsCursor` equivalent for the borrowed locals analysis. Since this analysis doesn't
Expand Down Expand Up @@ -1178,19 +1193,22 @@ impl<'a, 'mir, 'tcx> BorrowedLocalsResultsCursor<'a, 'mir, 'tcx> {
/// Performs a liveness analysis for borrows and raw pointers. This analysis also tracks `Local`s
/// corresponding to `Node`s of kind `NodeKind::LocalWithRefs`, as these could potentially refer to
/// or include references, pointers or exposed pointers.
#[derive(Clone)]
pub struct LiveBorrows<'mir, 'tcx> {
body: &'mir Body<'tcx>,
tcx: TyCtxt<'tcx>,
borrow_deps: BorrowDependencies<'mir, 'tcx>,
local_to_nodekind: FxHashMap<Local, NodeKind>,
reborrows_map: FxHashMap<Local, Local>,
}

impl<'mir, 'tcx> LiveBorrows<'mir, 'tcx> {
fn new(
body: &'mir Body<'tcx>,
tcx: TyCtxt<'tcx>,
borrow_deps: BorrowDependencies<'mir, 'tcx>,
local_to_nodekind: FxHashMap<Local, NodeKind>,
reborrows_map: FxHashMap<Local, Local>,
) -> Self {
LiveBorrows { body, tcx, borrow_deps }
LiveBorrows { body, tcx, local_to_nodekind, reborrows_map }
}

fn transfer_function<'b, T>(
Expand All @@ -1201,11 +1219,18 @@ impl<'mir, 'tcx> LiveBorrows<'mir, 'tcx> {
body: self.body,
tcx: self.tcx,
_trans: trans,
borrow_deps: &self.borrow_deps,
local_to_nodekind: &self.local_to_nodekind,
reborrows_map: &self.reborrows_map,
}
}
}

impl<'mir, 'tcx> crate::CloneAnalysis for LiveBorrows<'mir, 'tcx> {
fn clone_analysis(&self) -> Self {
self.clone()
}
}

impl<'a, 'tcx> AnalysisDomain<'tcx> for LiveBorrows<'a, 'tcx> {
type Domain = BitSet<Local>;
type Direction = Backward;
Expand Down Expand Up @@ -1258,7 +1283,8 @@ struct TransferFunction<'a, 'b, 'c, 'tcx, T> {
body: &'a Body<'tcx>,
tcx: TyCtxt<'tcx>,
_trans: &'b mut T,
borrow_deps: &'c BorrowDependencies<'a, 'tcx>,
local_to_nodekind: &'c FxHashMap<Local, NodeKind>,
reborrows_map: &'c FxHashMap<Local, Local>,
}

impl<'a, 'b, 'c, 'tcx, T> TransferFunction<'a, 'b, 'c, 'tcx, T>
Expand All @@ -1267,21 +1293,21 @@ where
{
fn gen(&mut self, local: Local) {
debug!("gen {:?}", local);
if let Some(reborrowed_local) = self.borrow_deps.reborrows_map.get(&local) {
if let Some(reborrowed_local) = self.reborrows_map.get(&local) {
self._trans.gen(*reborrowed_local);
} else {
if self.borrow_deps.dep_graph.locals_to_node_indexes.get(&local).is_some() {
if self.local_to_nodekind.get(&local).is_some() {
self._trans.gen(local)
}
}
}

fn kill(&mut self, local: Local) {
debug!("killing {:?}", local);
if let Some(reborrowed_local) = self.borrow_deps.reborrows_map.get(&local) {
if let Some(reborrowed_local) = self.reborrows_map.get(&local) {
self._trans.kill(*reborrowed_local);
} else {
if self.borrow_deps.dep_graph.locals_to_node_indexes.get(&local).is_some() {
if self.local_to_nodekind.get(&local).is_some() {
self._trans.kill(local)
}
}
Expand Down Expand Up @@ -1312,16 +1338,10 @@ where
self.visit_rvalue(&assign.1, location);
}
_ => {
if let Some(node_idx) = self
.borrow_deps
.dep_graph
.locals_to_node_indexes
.get(&lhs_place.local)
if let Some(NodeKind::LocalWithRefs(_)) =
self.local_to_nodekind.get(&lhs_place.local)
{
let node = self.borrow_deps.dep_graph.node(*node_idx);
if let NodeKind::LocalWithRefs(_) = node.data {
self.kill(lhs_place.local);
}
self.kill(lhs_place.local);
}
self.super_assign(&assign.0, &assign.1, location);
}
Expand Down Expand Up @@ -1357,13 +1377,8 @@ where
self.gen(local);
}
_ => {
if let Some(node_idx) =
self.borrow_deps.dep_graph.locals_to_node_indexes.get(&local)
{
let node = self.borrow_deps.dep_graph.node(*node_idx);
if matches!(node.data, NodeKind::LocalWithRefs(_)) {
self.gen(local);
}
if let Some(NodeKind::LocalWithRefs(_)) = self.local_to_nodekind.get(&local) {
self.gen(local);
}
}
}
Expand Down Expand Up @@ -1392,20 +1407,13 @@ where
for arg in args {
match arg {
Operand::Copy(place) | Operand::Move(place) => {
if let Some(node_idx) = self
.borrow_deps
.dep_graph
.locals_to_node_indexes
.get(&place.local)
if let Some(NodeKind::LocalWithRefs(_)) =
self.local_to_nodekind.get(&place.local)
{
let node = self.borrow_deps.dep_graph.node(*node_idx);

// these are `Local`s that contain references/pointers or are raw pointers
// that were assigned to raw pointers, which were cast to usize. Since the
// function call is free to use these in any form, we need to gen them here.
if let NodeKind::LocalWithRefs(_) = node.data {
self.gen(place.local);
}
self.gen(place.local);
} else {
self.super_operand(arg, location)
}
Expand All @@ -1424,20 +1432,13 @@ where

match value {
Operand::Copy(place) | Operand::Move(place) => {
if let Some(node_idx) = self
.borrow_deps
.dep_graph
.locals_to_node_indexes
.get(&place.local)
if let Some(NodeKind::LocalWithRefs(_)) =
self.local_to_nodekind.get(&place.local)
{
let node = self.borrow_deps.dep_graph.node(*node_idx);

// these are `Local`s that contain references/pointers or are raw pointers
// that were assigned to raw pointers, which were cast to usize. Since the
// function call is free to use these in any form, we need to gen them here.
if let NodeKind::LocalWithRefs(_) = node.data {
self.gen(place.local);
}
self.gen(place.local);
} else {
self.super_operand(value, location)
}
Expand Down

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