Jakob Degen fe40240e4d Clarify which kinds of MIR are allowed during which phases.
This enhances documentation with these details and extends the validator to check these requirements
more thoroughly. As a part of this, we add a new `Deaggregated` phase, and rename other phases so
that their names more naturally correspond to what they represent.
2022-03-23 18:34:08 -04:00

51 lines
1.7 KiB
Rust

use crate::util::expand_aggregate;
use crate::MirPass;
use rustc_middle::mir::*;
use rustc_middle::ty::TyCtxt;
pub struct Deaggregator;
impl<'tcx> MirPass<'tcx> for Deaggregator {
fn phase_change(&self) -> Option<MirPhase> {
Some(MirPhase::Deaggregated)
}
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let (basic_blocks, local_decls) = body.basic_blocks_and_local_decls_mut();
let local_decls = &*local_decls;
for bb in basic_blocks {
bb.expand_statements(|stmt| {
// FIXME(eddyb) don't match twice on `stmt.kind` (post-NLL).
match stmt.kind {
// FIXME(#48193) Deaggregate arrays when it's cheaper to do so.
StatementKind::Assign(box (
_,
Rvalue::Aggregate(box AggregateKind::Array(_), _),
)) => {
return None;
}
StatementKind::Assign(box (_, Rvalue::Aggregate(_, _))) => {}
_ => return None,
}
let stmt = stmt.replace_nop();
let source_info = stmt.source_info;
let StatementKind::Assign(box (lhs, Rvalue::Aggregate(kind, operands))) = stmt.kind else {
bug!();
};
Some(expand_aggregate(
lhs,
operands.into_iter().map(|op| {
let ty = op.ty(local_decls, tcx);
(op, ty)
}),
*kind,
source_info,
tcx,
))
});
}
}
}