// their declared shapes for computations. Must be non-empty.
    std::vector<XlaShapeLayoutHelpers::ShapeDeterminationFns>
        shape_determination_fns;

    // If padded_shape_fn is empty, a default implementation that returns
    // the logical on-device shape without padding is used.
    PaddedShapeFn padded_shape_fn;

    // Set of devices to use. This controls which of the devices on the given

///
/// Hashable TaggedValues overload `AbslHashValue`. Non-hashable structures
/// return 0.
template <>
struct TaggedValueHash<TaggedValue> {
  size_t operator()(const TaggedValue& v) const;
};

/// @brief Hash implementation for TaggedValue Tuples.
template <>
struct TaggedValueHash<Tuple> {
  size_t operator()(const Tuple& t) const;
};

/// @brief The basic `TaggedValue` tagged union type.
///

TF_CAPI_EXPORT extern void TFE_HostAddressSpace(TFE_Context* ctx,
                                                TF_Buffer* buf);

// APIs for generically dealing with op attributes (e.g. when forwarding them
// through custom device implementations).
//
// TODO(allenl): Currently these are black boxes, but we should have some way to
// inspect values. This would let people e.g. copy over most attributes and then
// modify some based on their values.