void Visit(Exp *lval)
{
// match any access which uses a GC thing type as an rvalue,
// including those where the thing is not actually dereferenced.
// we are watching not just for direct accesses to the thing,
// but to places where it is copied to arguments, a return value,
// a variable or heap location. any use of an GC thing pointer
// not protected against GC is considered to be an error, and adding
// these asserts aggressively lets us discharge reports easier and
// generate reports close to the site of the actual problem.
if (!lval->IsDrf())
return;
ExpDrf *nlval = lval->AsDrf();
Type *type = nlval->GetType();
if (type && type->IsCSU() && TypeIsGCThing(type->AsCSU())) {
AssertInfo info;
info.kind = ASK_GCSafe;
info.cls = ASC_Check;
info.point = point;
Exp *target = nlval->GetTarget();
if (target->IsFld() &&
BlockSummary::FieldIsGCSafe(target->AsFld()->GetField())) {
info.bit = Bit::MakeConstant(true);
} else {
Exp *gcsafe = Exp::MakeGCSafe(nlval->GetTarget(), false);
info.bit = Bit::MakeVar(gcsafe);
}
asserts.PushBack(info);
}
}
