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use flowgraph::ControlFlowGraph;
use ir::entities::AnyEntity;
use ir::{ExpandedProgramPoint, Function, Inst, ProgramOrder, ProgramPoint, Value};
use isa::TargetIsa;
use regalloc::liveness::Liveness;
use regalloc::liverange::LiveRange;
use std::cmp::Ordering;
use timing;
use verifier::VerifierResult;
pub fn verify_liveness(
isa: &TargetIsa,
func: &Function,
cfg: &ControlFlowGraph,
liveness: &Liveness,
) -> VerifierResult<()> {
let _tt = timing::verify_liveness();
let verifier = LivenessVerifier {
isa,
func,
cfg,
liveness,
};
verifier.check_ebbs()?;
verifier.check_insts()?;
Ok(())
}
struct LivenessVerifier<'a> {
isa: &'a TargetIsa,
func: &'a Function,
cfg: &'a ControlFlowGraph,
liveness: &'a Liveness,
}
impl<'a> LivenessVerifier<'a> {
fn check_ebbs(&self) -> VerifierResult<()> {
for ebb in self.func.layout.ebbs() {
for &val in self.func.dfg.ebb_params(ebb) {
let lr = match self.liveness.get(val) {
Some(lr) => lr,
None => return err!(ebb, "EBB arg {} has no live range", val),
};
self.check_lr(ebb.into(), val, lr)?;
}
}
Ok(())
}
fn check_insts(&self) -> VerifierResult<()> {
for ebb in self.func.layout.ebbs() {
for inst in self.func.layout.ebb_insts(ebb) {
let encoding = self.func.encodings[inst];
for &val in self.func.dfg.inst_results(inst) {
let lr = match self.liveness.get(val) {
Some(lr) => lr,
None => return err!(inst, "{} has no live range", val),
};
self.check_lr(inst.into(), val, lr)?;
if encoding.is_legal() {
if lr.affinity.is_unassigned() {
return err!(
inst,
"{} is a ghost value defined by a real [{}] instruction",
val,
self.isa.encoding_info().display(encoding)
);
}
} else if !lr.affinity.is_unassigned() {
return err!(
inst,
"{} is a real {} value defined by a ghost instruction",
val,
lr.affinity.display(&self.isa.register_info())
);
}
}
for &val in self.func.dfg.inst_args(inst) {
let lr = match self.liveness.get(val) {
Some(lr) => lr,
None => return err!(inst, "{} has no live range", val),
};
if !self.live_at_use(lr, inst) {
return err!(inst, "{} is not live at this use", val);
}
if encoding.is_legal() && lr.affinity.is_unassigned() {
return err!(
inst,
"{} is a ghost value used by a real [{}] instruction",
val,
self.isa.encoding_info().display(encoding)
);
}
}
}
}
Ok(())
}
fn live_at_use(&self, lr: &LiveRange, inst: Inst) -> bool {
let ctx = self.liveness.context(&self.func.layout);
if ctx.order.cmp(lr.def(), inst) == Ordering::Less
&& ctx.order.cmp(inst, lr.def_local_end()) != Ordering::Greater
{
return true;
}
match lr.livein_local_end(ctx.order.inst_ebb(inst).unwrap(), ctx) {
Some(end) => ctx.order.cmp(inst, end) != Ordering::Greater,
None => false,
}
}
fn check_lr(&self, def: ProgramPoint, val: Value, lr: &LiveRange) -> VerifierResult<()> {
let l = &self.func.layout;
let loc: AnyEntity = match def.into() {
ExpandedProgramPoint::Ebb(e) => e.into(),
ExpandedProgramPoint::Inst(i) => i.into(),
};
if lr.def() != def {
return err!(loc, "Wrong live range def ({}) for {}", lr.def(), val);
}
if lr.is_dead() {
if !lr.is_local() {
return err!(loc, "Dead live range {} should be local", val);
} else {
return Ok(());
}
}
let def_ebb = match def.into() {
ExpandedProgramPoint::Ebb(e) => e,
ExpandedProgramPoint::Inst(i) => l.inst_ebb(i).unwrap(),
};
match lr.def_local_end().into() {
ExpandedProgramPoint::Ebb(e) => {
return err!(loc, "Def local range for {} can't end at {}", val, e)
}
ExpandedProgramPoint::Inst(i) => {
if self.func.layout.inst_ebb(i) != Some(def_ebb) {
return err!(loc, "Def local end for {} in wrong ebb", val);
}
}
}
for (mut ebb, end) in lr.liveins(self.liveness.context(l)) {
if !l.is_ebb_inserted(ebb) {
return err!(loc, "{} livein at {} which is not in the layout", val, ebb);
}
let end_ebb = match l.inst_ebb(end) {
Some(e) => e,
None => {
return err!(
loc,
"{} livein for {} ends at {} which is not in the layout",
val,
ebb,
end
)
}
};
loop {
for (_, pred) in self.cfg.pred_iter(ebb) {
if !self.live_at_use(lr, pred) {
return err!(
pred,
"{} is live in to {} but not live at predecessor",
val,
ebb
);
}
}
if ebb == end_ebb {
break;
}
ebb = match l.next_ebb(ebb) {
Some(e) => e,
None => return err!(loc, "end of {} livein ({}) never reached", val, end_ebb),
};
}
}
Ok(())
}
}