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use rustc_middle::mir::*;
use rustc_middle::ty::TyCtxt;
use crate::util;
use crate::MirPass;
use rustc_middle::mir::patch::MirPatch;
pub struct AddMovesForPackedDrops;
impl<'tcx> MirPass<'tcx> for AddMovesForPackedDrops {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
debug!("add_moves_for_packed_drops({:?} @ {:?})", body.source, body.span);
add_moves_for_packed_drops(tcx, body);
}
}
pub fn add_moves_for_packed_drops<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let patch = add_moves_for_packed_drops_patch(tcx, body);
patch.apply(body);
}
fn add_moves_for_packed_drops_patch<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>) -> MirPatch<'tcx> {
let def_id = body.source.def_id();
let mut patch = MirPatch::new(body);
let param_env = tcx.param_env(def_id);
for (bb, data) in body.basic_blocks.iter_enumerated() {
let loc = Location { block: bb, statement_index: data.statements.len() };
let terminator = data.terminator();
match terminator.kind {
TerminatorKind::Drop { place, .. }
if util::is_disaligned(tcx, body, param_env, place) =>
{
add_move_for_packed_drop(tcx, body, &mut patch, terminator, loc, data.is_cleanup);
}
TerminatorKind::DropAndReplace { .. } => {
span_bug!(terminator.source_info.span, "replace in AddMovesForPackedDrops");
}
_ => {}
}
}
patch
}
fn add_move_for_packed_drop<'tcx>(
tcx: TyCtxt<'tcx>,
body: &Body<'tcx>,
patch: &mut MirPatch<'tcx>,
terminator: &Terminator<'tcx>,
loc: Location,
is_cleanup: bool,
) {
debug!("add_move_for_packed_drop({:?} @ {:?})", terminator, loc);
let TerminatorKind::Drop { ref place, target, unwind } = terminator.kind else {
unreachable!();
};
let source_info = terminator.source_info;
let ty = place.ty(body, tcx).ty;
let temp = patch.new_temp(ty, terminator.source_info.span);
let storage_dead_block = patch.new_block(BasicBlockData {
statements: vec![Statement { source_info, kind: StatementKind::StorageDead(temp) }],
terminator: Some(Terminator { source_info, kind: TerminatorKind::Goto { target } }),
is_cleanup,
});
patch.add_statement(loc, StatementKind::StorageLive(temp));
patch.add_assign(loc, Place::from(temp), Rvalue::Use(Operand::Move(*place)));
patch.patch_terminator(
loc.block,
TerminatorKind::Drop { place: Place::from(temp), target: storage_dead_block, unwind },
);
}