/// Recursively walk into the given formal index type, expanding tuples,
/// in order to form the arguments to a subscript accessor.
static void translateIndices(SILGenFunction &gen, SILLocation loc,
AbstractionPattern pattern, CanType formalType,
ArrayRef<ManagedValue> &sourceIndices,
RValue &result) {
// Expand if the pattern was a tuple.
if (pattern.isTuple()) {
auto formalTupleType = cast<TupleType>(formalType);
for (auto i : indices(formalTupleType.getElementTypes())) {
translateIndices(gen, loc, pattern.getTupleElementType(i),
formalTupleType.getElementType(i),
sourceIndices, result);
}
return;
}
assert(!sourceIndices.empty() && "ran out of elements in index!");
ManagedValue value = sourceIndices.front();
sourceIndices = sourceIndices.slice(1);
// We're going to build an RValue here, so make sure we translate
// indirect arguments to be scalar if we have a loadable type.
if (value.getType().isAddress()) {
auto &valueTL = gen.getTypeLowering(value.getType());
if (!valueTL.isAddressOnly()) {
value = gen.emitLoad(loc, value.forward(gen), valueTL,
SGFContext(), IsTake);
}
}
// Reabstract the subscripts from the requirement pattern to the
// formal type.
value = gen.emitOrigToSubstValue(loc, value, pattern, formalType);
// Invoking the accessor will expect a value of the formal type, so
// don't reabstract to that here.
// Add that to the result, further expanding if necessary.
result.addElement(gen, value, formalType, loc);
}
