bjoernager/rust
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Make SROA expand assignments.

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This commit is contained in:
Camille GILLOT 2023-02-05 09:31:27 +00:00
parent 0843acbea6
commit dc4fe8e295
6 changed files with 188 additions and 32 deletions
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88
compiler/rustc_mir_transform/src/sroa.rs
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@ -78,10 +78,15 @@ fn escaping_locals(body: &Body<'_>) -> BitSet<Local> {
rvalue: &Rvalue<'tcx>,
location: Location,
) {
if lvalue.as_local().is_some() && let Rvalue::Aggregate(..) = rvalue {
// Aggregate assignments are expanded in run_pass.
self.visit_rvalue(rvalue, location);
return;
if lvalue.as_local().is_some() {
match rvalue {
// Aggregate assignments are expanded in run_pass.
Rvalue::Aggregate(..) | Rvalue::Use(..) => {
self.visit_rvalue(rvalue, location);
return;
}
_ => {}
}
}
self.super_assign(lvalue, rvalue, location)
}
@ -195,10 +200,9 @@ fn replace_flattened_locals<'tcx>(
return;
}
let mut fragments = IndexVec::new();
let mut fragments = IndexVec::<_, Option<Vec<_>>>::from_elem(None, &body.local_decls);
for (k, v) in &replacements.fields {
fragments.ensure_contains_elem(k.local, || Vec::new());
fragments[k.local].push((k.projection, *v));
fragments[k.local].get_or_insert_default().push((k.projection, *v));
}
debug!(?fragments);
@ -235,7 +239,7 @@ struct ReplacementVisitor<'tcx, 'll> {
all_dead_locals: BitSet<Local>,
/// Pre-computed list of all "new" locals for each "old" local. This is used to expand storage
/// and deinit statement and debuginfo.
fragments: IndexVec<Local, Vec<(&'tcx [PlaceElem<'tcx>], Local)>>,
fragments: IndexVec<Local, Option<Vec<(&'tcx [PlaceElem<'tcx>], Local)>>>,
patch: MirPatch<'tcx>,
}
@ -243,9 +247,9 @@ impl<'tcx, 'll> ReplacementVisitor<'tcx, 'll> {
fn gather_debug_info_fragments(
&self,
place: PlaceRef<'tcx>,
) -> Vec<VarDebugInfoFragment<'tcx>> {
) -> Option<Vec<VarDebugInfoFragment<'tcx>>> {
let mut fragments = Vec::new();
let parts = &self.fragments[place.local];
let Some(parts) = &self.fragments[place.local] else { return None };
for (proj, replacement_local) in parts {
if proj.starts_with(place.projection) {
fragments.push(VarDebugInfoFragment {
@ -254,7 +258,7 @@ impl<'tcx, 'll> ReplacementVisitor<'tcx, 'll> {
});
}
}
fragments
Some(fragments)
}
fn replace_place(&self, place: PlaceRef<'tcx>) -> Option<Place<'tcx>> {
@ -276,8 +280,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
match statement.kind {
StatementKind::StorageLive(l) => {
if self.all_dead_locals.contains(l) {
let final_locals = &self.fragments[l];
if let Some(final_locals) = &self.fragments[l] {
for &(_, fl) in final_locals {
self.patch.add_statement(location, StatementKind::StorageLive(fl));
}
@ -286,8 +289,7 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
return;
}
StatementKind::StorageDead(l) => {
if self.all_dead_locals.contains(l) {
let final_locals = &self.fragments[l];
if let Some(final_locals) = &self.fragments[l] {
for &(_, fl) in final_locals {
self.patch.add_statement(location, StatementKind::StorageDead(fl));
}
@ -297,9 +299,8 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
}
StatementKind::Deinit(box ref place) => {
if let Some(local) = place.as_local()
&& self.all_dead_locals.contains(local)
&& let Some(final_locals) = &self.fragments[local]
{
let final_locals = &self.fragments[local];
for &(_, fl) in final_locals {
self.patch.add_statement(
location,
@ -313,9 +314,8 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
StatementKind::Assign(box (ref place, Rvalue::Aggregate(_, ref operands))) => {
if let Some(local) = place.as_local()
&& self.all_dead_locals.contains(local)
&& let Some(final_locals) = &self.fragments[local]
{
let final_locals = &self.fragments[local];
for &(projection, fl) in final_locals {
let &[PlaceElem::Field(index, _)] = projection else { bug!() };
let index = index.as_usize();
@ -330,6 +330,48 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
}
}
StatementKind::Assign(box (ref place, Rvalue::Use(Operand::Constant(_)))) => {
if let Some(local) = place.as_local()
&& let Some(final_locals) = &self.fragments[local]
{
for &(projection, fl) in final_locals {
let rvalue = Rvalue::Use(Operand::Move(place.project_deeper(projection, self.tcx)));
self.patch.add_statement(
location,
StatementKind::Assign(Box::new((fl.into(), rvalue))),
);
}
self.all_dead_locals.remove(local);
return;
}
}
StatementKind::Assign(box (ref lhs, Rvalue::Use(ref op))) => {
let (rplace, copy) = match op {
Operand::Copy(rplace) => (rplace, true),
Operand::Move(rplace) => (rplace, false),
Operand::Constant(_) => bug!(),
};
if let Some(local) = lhs.as_local()
&& let Some(final_locals) = &self.fragments[local]
{
for &(projection, fl) in final_locals {
let rplace = rplace.project_deeper(projection, self.tcx);
let rvalue = if copy {
Rvalue::Use(Operand::Copy(rplace))
} else {
Rvalue::Use(Operand::Move(rplace))
};
self.patch.add_statement(
location,
StatementKind::Assign(Box::new((fl.into(), rvalue))),
);
}
statement.make_nop();
return;
}
}
_ => {}
}
self.super_statement(statement, location)
@ -348,9 +390,8 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
VarDebugInfoContents::Place(ref mut place) => {
if let Some(repl) = self.replace_place(place.as_ref()) {
*place = repl;
} else if self.all_dead_locals.contains(place.local) {
} else if let Some(fragments) = self.gather_debug_info_fragments(place.as_ref()) {
let ty = place.ty(self.local_decls, self.tcx).ty;
let fragments = self.gather_debug_info_fragments(place.as_ref());
var_debug_info.value = VarDebugInfoContents::Composite { ty, fragments };
}
}
@ -361,8 +402,9 @@ impl<'tcx, 'll> MutVisitor<'tcx> for ReplacementVisitor<'tcx, 'll> {
if let Some(repl) = self.replace_place(fragment.contents.as_ref()) {
fragment.contents = repl;
true
} else if self.all_dead_locals.contains(fragment.contents.local) {
let frg = self.gather_debug_info_fragments(fragment.contents.as_ref());
} else if let Some(frg) =
self.gather_debug_info_fragments(fragment.contents.as_ref())
{
new_fragments.extend(frg.into_iter().map(|mut f| {
f.projection.splice(0..0, fragment.projection.iter().copied());
f