Method DetectAsyncHazard

layers/sync/sync_access_state.cpp:273–295

Asynchronous Hazards occur between subpasses with no connection through the DAG

// Asynchronous Hazards occur between subpasses with no connection through the DAG
HazardResult AccessState::DetectAsyncHazard(const SyncAccessInfo& usage_info, const ResourceUsageTag start_tag,
                                            QueueId queue_id) const {
    // Async checks need to not go back further than the start of the subpass, as we only want to find hazards between the async
    // subpasses.  Anything older than that should have been checked at the start of each subpass, taking into account all of
    // the raster ordering rules.
    if (IsRead(usage_info.access_index)) {
        if (last_write.has_value() && last_write->queue == queue_id && (last_write->tag >= start_tag)) {
            return HazardResult::HazardVsPriorWrite(this, usage_info, READ_RACING_WRITE, *last_write);
        }
    } else {
        if (last_write.has_value() && last_write->queue == queue_id && (last_write->tag >= start_tag)) {
            return HazardResult::HazardVsPriorWrite(this, usage_info, WRITE_RACING_WRITE, *last_write);
        } else if (HasReads()) {
            // Any reads during the other subpass will conflict with this write, so we need to check them all.
            for (const auto& read_access : GetReads()) {
                if (read_access.queue == queue_id && read_access.tag >= start_tag) {
                    return HazardResult::HazardVsPriorRead(this, usage_info, WRITE_RACING_READ, read_access);
                }
            }
        }
    }
    return {};
}

HazardResult AccessState::DetectAsyncHazard(const AccessState& recorded_use, const ResourceUsageRange& tag_range,
                                            ResourceUsageTag start_tag, QueueId queue_id) const {