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use rustc::hir::def_id::DefId;
use rustc::mir::*;
use rustc::ty::TyCtxt;
use transform::{MirPass, MirSource};
use util::patch::MirPatch;
use util;
pub struct AddMovesForPackedDrops;
impl MirPass for AddMovesForPackedDrops {
fn run_pass<'a, 'tcx>(&self,
tcx: TyCtxt<'a, 'tcx, 'tcx>,
src: MirSource,
mir: &mut Mir<'tcx>)
{
debug!("add_moves_for_packed_drops({:?} @ {:?})", src, mir.span);
add_moves_for_packed_drops(tcx, mir, src.def_id);
}
}
pub fn add_moves_for_packed_drops<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
mir: &mut Mir<'tcx>,
def_id: DefId)
{
let patch = add_moves_for_packed_drops_patch(tcx, mir, def_id);
patch.apply(mir);
}
fn add_moves_for_packed_drops_patch<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
mir: &Mir<'tcx>,
def_id: DefId)
-> MirPatch<'tcx>
{
let mut patch = MirPatch::new(mir);
let param_env = tcx.param_env(def_id);
for (bb, data) in mir.basic_blocks().iter_enumerated() {
let loc = Location { block: bb, statement_index: data.statements.len() };
let terminator = data.terminator();
match terminator.kind {
TerminatorKind::Drop { ref location, .. }
if util::is_disaligned(tcx, mir, param_env, location) =>
{
add_move_for_packed_drop(tcx, mir, &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<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
mir: &Mir<'tcx>,
patch: &mut MirPatch<'tcx>,
terminator: &Terminator<'tcx>,
loc: Location,
is_cleanup: bool)
{
debug!("add_move_for_packed_drop({:?} @ {:?})", terminator, loc);
let (location, target, unwind) = match terminator.kind {
TerminatorKind::Drop { ref location, target, unwind } =>
(location, target, unwind),
_ => unreachable!()
};
let source_info = terminator.source_info;
let ty = location.ty(mir, tcx).to_ty(tcx);
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::Local(temp),
Rvalue::Use(Operand::Move(location.clone())));
patch.patch_terminator(loc.block, TerminatorKind::Drop {
location: Place::Local(temp),
target: storage_dead_block,
unwind
});
}