BlockSharedMemStMemberMasterSync.hpp

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/* Copyright 2022 Benjamin Worpitz, Erik Zenker, Matthias Werner, René Widera
 * SPDX-License-Identifier: MPL-2.0
 */
 
#pragma once
 
#include "alpaka/block/shared/st/Traits.hpp"
#include "alpaka/block/shared/st/detail/BlockSharedMemStMemberImpl.hpp"
#include "alpaka/core/AlignedAlloc.hpp"
#include "alpaka/core/Common.hpp"
#include "alpaka/core/Vectorize.hpp"
 
#include <functional>
#include <memory>
#include <utility>
#include <vector>
 
namespace alpaka
{
    template<std::size_t TDataAlignBytes = core::vectorization::defaultAlignment>
    class BlockSharedMemStMemberMasterSync
        : public detail::BlockSharedMemStMemberImpl<TDataAlignBytes>
        , public interface::Implements<ConceptBlockSharedSt, BlockSharedMemStMemberMasterSync<TDataAlignBytes>>
    {
    public:
        BlockSharedMemStMemberMasterSync(
            uint8_t* mem,
            std::size_t capacity,
            std::function<void()> fnSync,
            std::function<bool()> fnIsMasterThread)
            : detail::BlockSharedMemStMemberImpl<TDataAlignBytes>(mem, capacity)
            , m_syncFn(std::move(fnSync))
            , m_isMasterThreadFn(std::move(fnIsMasterThread))
        {
        }
 
        std::function<void()> m_syncFn;
        std::function<bool()> m_isMasterThreadFn;
    };
 
    namespace trait
    {
#if BOOST_COMP_GNUC
#    pragma GCC diagnostic push
#    pragma GCC diagnostic ignored                                                                                    \
        "-Wcast-align" // "cast from 'unsigned char*' to 'unsigned int*' increases required alignment of target type"
#endif
        template<typename T, std::size_t TDataAlignBytes, std::size_t TuniqueId>
        struct DeclareSharedVar<T, TuniqueId, BlockSharedMemStMemberMasterSync<TDataAlignBytes>>
        {
            ALPAKA_FN_HOST static auto declareVar(
                BlockSharedMemStMemberMasterSync<TDataAlignBytes> const& blockSharedMemSt) -> T&
            {
                auto* data = blockSharedMemSt.template getVarPtr<T>(TuniqueId);
 
                if(!data)
                {
                    // Assure that all threads have executed the return of the last allocBlockSharedArr function (if
                    // there was one before).
                    blockSharedMemSt.m_syncFn();
                    if(blockSharedMemSt.m_isMasterThreadFn())
                    {
                        blockSharedMemSt.template alloc<T>(TuniqueId);
                    }
 
                    blockSharedMemSt.m_syncFn();
                    // lookup for the data chunk allocated by the master thread
                    data = blockSharedMemSt.template getLatestVarPtr<T>();
                }
                ALPAKA_ASSERT(data != nullptr);
                return *data;
            }
        };
#if BOOST_COMP_GNUC
#    pragma GCC diagnostic pop
#endif
        template<std::size_t TDataAlignBytes>
        struct FreeSharedVars<BlockSharedMemStMemberMasterSync<TDataAlignBytes>>
        {
            ALPAKA_FN_HOST static auto freeVars(BlockSharedMemStMemberMasterSync<TDataAlignBytes> const&) -> void
            {
                // shared memory block data will be reused
            }
        };
    } // namespace trait
} // namespace alpaka