buffer_cache: Implement a generic buffer cache

Implements a templated class with a similar approach to our current
generic texture cache. It is designed to be compatible with Vulkan and
OpenGL,

2 files changed, 301 insertions, 0 deletions

diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index 7aefd4035..8753383b8 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_library(video_core STATIC
+    buffer_cache.h
     dma_pusher.cpp
     dma_pusher.h
     debug_utils/debug_utils.cpp
diff --git a/src/video_core/buffer_cache.h b/src/video_core/buffer_cache.h
new file mode 100644
index 000000000..eb0ec45c2
--- /dev/null
+++ b/src/video_core/buffer_cache.h
@@ -0,0 +1,300 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <memory>
+#include <mutex>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+#include <vector>
+
+#include "common/alignment.h"
+#include "common/common_types.h"
+#include "core/core.h"
+#include "video_core/memory_manager.h"
+#include "video_core/rasterizer_cache.h"
+
+namespace VideoCore {
+class RasterizerInterface;
+}
+
+namespace VideoCommon {
+
+template <typename BufferStorageType>
+class CachedBuffer final : public RasterizerCacheObject {
+public:
+    explicit CachedBuffer(VAddr cpu_addr, u8* host_ptr)
+        : RasterizerCacheObject{host_ptr}, host_ptr{host_ptr}, cpu_addr{cpu_addr} {}
+    ~CachedBuffer() override = default;
+
+    VAddr GetCpuAddr() const override {
+        return cpu_addr;
+    }
+
+    std::size_t GetSizeInBytes() const override {
+        return size;
+    }
+
+    u8* GetWritableHostPtr() const {
+        return host_ptr;
+    }
+
+    std::size_t GetSize() const {
+        return size;
+    }
+
+    std::size_t GetCapacity() const {
+        return capacity;
+    }
+
+    bool IsInternalized() const {
+        return is_internal;
+    }
+
+    const BufferStorageType& GetBuffer() const {
+        return buffer;
+    }
+
+    void SetSize(std::size_t new_size) {
+        size = new_size;
+    }
+
+    void SetInternalState(bool is_internal_) {
+        is_internal = is_internal_;
+    }
+
+    BufferStorageType ExchangeBuffer(BufferStorageType buffer_, std::size_t new_capacity) {
+        capacity = new_capacity;
+        std::swap(buffer, buffer_);
+        return buffer_;
+    }
+
+private:
+    u8* host_ptr{};
+    VAddr cpu_addr{};
+    std::size_t size{};
+    std::size_t capacity{};
+    bool is_internal{};
+    BufferStorageType buffer;
+};
+
+template <typename BufferStorageType, typename BufferType, typename StreamBuffer>
+class BufferCache : public RasterizerCache<std::shared_ptr<CachedBuffer<BufferStorageType>>> {
+public:
+    using Buffer = std::shared_ptr<CachedBuffer<BufferStorageType>>;
+    using BufferInfo = std::pair<const BufferType*, u64>;
+
+    explicit BufferCache(VideoCore::RasterizerInterface& rasterizer, Core::System& system,
+                         std::unique_ptr<StreamBuffer> stream_buffer)
+        : RasterizerCache<Buffer>{rasterizer}, system{system},
+          stream_buffer{std::move(stream_buffer)}, stream_buffer_handle{
+                                                       this->stream_buffer->GetHandle()} {}
+    ~BufferCache() = default;
+
+    void Unregister(const Buffer& entry) override {
+        std::lock_guard lock{RasterizerCache<Buffer>::mutex};
+        if (entry->IsInternalized()) {
+            internalized_entries.erase(entry->GetCacheAddr());
+        }
+        ReserveBuffer(entry);
+        RasterizerCache<Buffer>::Unregister(entry);
+    }
+
+    void TickFrame() {
+        marked_for_destruction_index =
+            (marked_for_destruction_index + 1) % marked_for_destruction_ring_buffer.size();
+        MarkedForDestruction().clear();
+    }
+
+    [[nodiscard]] BufferInfo UploadMemory(GPUVAddr gpu_addr, std::size_t size,
+                                          std::size_t alignment = 4, bool internalize = false,
+                                          bool is_written = false) {
+        std::lock_guard lock{RasterizerCache<Buffer>::mutex};
+
+        auto& memory_manager = system.GPU().MemoryManager();
+        const auto host_ptr = memory_manager.GetPointer(gpu_addr);
+        if (!host_ptr) {
+            return {GetEmptyBuffer(size), 0};
+        }
+        const auto cache_addr = ToCacheAddr(host_ptr);
+
+        // Cache management is a big overhead, so only cache entries with a given size.
+        // TODO: Figure out which size is the best for given games.
+        constexpr std::size_t max_stream_size = 0x800;
+        if (!internalize && size < max_stream_size &&
+            internalized_entries.find(cache_addr) == internalized_entries.end()) {
+            return StreamBufferUpload(host_ptr, size, alignment);
+        }
+
+        auto entry = RasterizerCache<Buffer>::TryGet(cache_addr);
+        if (!entry) {
+            return FixedBufferUpload(gpu_addr, host_ptr, size, internalize, is_written);
+        }
+
+        if (entry->GetSize() < size) {
+            IncreaseBufferSize(entry, size);
+        }
+        if (is_written) {
+            entry->MarkAsModified(true, *this);
+        }
+        return {ToHandle(entry->GetBuffer()), 0};
+    }
+
+    /// Uploads from a host memory. Returns the OpenGL buffer where it's located and its offset.
+    [[nodiscard]] BufferInfo UploadHostMemory(const void* raw_pointer, std::size_t size,
+                                              std::size_t alignment = 4) {
+        std::lock_guard lock{RasterizerCache<Buffer>::mutex};
+        return StreamBufferUpload(raw_pointer, size, alignment);
+    }
+
+    void Map(std::size_t max_size) {
+        std::tie(buffer_ptr, buffer_offset_base, invalidated) = stream_buffer->Map(max_size, 4);
+        buffer_offset = buffer_offset_base;
+    }
+
+    /// Finishes the upload stream, returns true on bindings invalidation.
+    bool Unmap() {
+        stream_buffer->Unmap(buffer_offset - buffer_offset_base);
+        return std::exchange(invalidated, false);
+    }
+
+protected:
+    void FlushObjectInner(const Buffer& entry) override {
+        DownloadBufferData(entry->GetBuffer(), 0, entry->GetSize(), entry->GetWritableHostPtr());
+    }
+
+    virtual BufferStorageType CreateBuffer(std::size_t size) = 0;
+
+    virtual const BufferType* ToHandle(const BufferStorageType& storage) = 0;
+
+    virtual const BufferType* GetEmptyBuffer(std::size_t size) = 0;
+
+    virtual void UploadBufferData(const BufferStorageType& buffer, std::size_t offset,
+                                  std::size_t size, const u8* data) = 0;
+
+    virtual void DownloadBufferData(const BufferStorageType& buffer, std::size_t offset,
+                                    std::size_t size, u8* data) = 0;
+
+    virtual void CopyBufferData(const BufferStorageType& src, const BufferStorageType& dst,
+                                std::size_t src_offset, std::size_t dst_offset,
+                                std::size_t size) = 0;
+
+private:
+    BufferInfo StreamBufferUpload(const void* raw_pointer, std::size_t size,
+                                  std::size_t alignment) {
+        AlignBuffer(alignment);
+        const std::size_t uploaded_offset = buffer_offset;
+        std::memcpy(buffer_ptr, raw_pointer, size);
+
+        buffer_ptr += size;
+        buffer_offset += size;
+        return {&stream_buffer_handle, uploaded_offset};
+    }
+
+    BufferInfo FixedBufferUpload(GPUVAddr gpu_addr, u8* host_ptr, std::size_t size,
+                                 bool internalize, bool is_written) {
+        auto& memory_manager = Core::System::GetInstance().GPU().MemoryManager();
+        const auto cpu_addr = memory_manager.GpuToCpuAddress(gpu_addr);
+        ASSERT(cpu_addr);
+
+        auto entry = GetUncachedBuffer(*cpu_addr, host_ptr);
+        entry->SetSize(size);
+        entry->SetInternalState(internalize);
+        RasterizerCache<Buffer>::Register(entry);
+
+        if (internalize) {
+            internalized_entries.emplace(ToCacheAddr(host_ptr));
+        }
+        if (is_written) {
+            entry->MarkAsModified(true, *this);
+        }
+
+        if (entry->GetCapacity() < size) {
+            MarkedForDestruction().push_back(entry->ExchangeBuffer(CreateBuffer(size), size));
+        }
+
+        UploadBufferData(entry->GetBuffer(), 0, size, host_ptr);
+        return {ToHandle(entry->GetBuffer()), 0};
+    }
+
+    void IncreaseBufferSize(Buffer& entry, std::size_t new_size) {
+        const std::size_t old_size = entry->GetSize();
+        if (entry->GetCapacity() < new_size) {
+            const auto& old_buffer = entry->GetBuffer();
+            auto new_buffer = CreateBuffer(new_size);
+
+            // Copy bits from the old buffer to the new buffer.
+            CopyBufferData(old_buffer, new_buffer, 0, 0, old_size);
+            MarkedForDestruction().push_back(
+                entry->ExchangeBuffer(std::move(new_buffer), new_size));
+
+            // This buffer could have been used
+            invalidated = true;
+        }
+        // Upload the new bits.
+        const std::size_t size_diff = new_size - old_size;
+        UploadBufferData(entry->GetBuffer(), old_size, size_diff, entry->GetHostPtr() + old_size);
+
+        // Update entry's size in the object and in the cache.
+        Unregister(entry);
+
+        entry->SetSize(new_size);
+        RasterizerCache<Buffer>::Register(entry);
+    }
+
+    Buffer GetUncachedBuffer(VAddr cpu_addr, u8* host_ptr) {
+        if (auto entry = TryGetReservedBuffer(host_ptr)) {
+            return entry;
+        }
+        return std::make_shared<Buffer::element_type>(cpu_addr, host_ptr);
+    }
+
+    Buffer TryGetReservedBuffer(u8* host_ptr) {
+        const auto it = buffer_reserve.find(ToCacheAddr(host_ptr));
+        if (it == buffer_reserve.end()) {
+            return {};
+        }
+        auto& reserve = it->second;
+        auto entry = reserve.back();
+        reserve.pop_back();
+        return entry;
+    }
+
+    void ReserveBuffer(Buffer entry) {
+        buffer_reserve[entry->GetCacheAddr()].push_back(std::move(entry));
+    }
+
+    void AlignBuffer(std::size_t alignment) {
+        // Align the offset, not the mapped pointer
+        const std::size_t offset_aligned = Common::AlignUp(buffer_offset, alignment);
+        buffer_ptr += offset_aligned - buffer_offset;
+        buffer_offset = offset_aligned;
+    }
+
+    std::vector<BufferStorageType>& MarkedForDestruction() {
+        return marked_for_destruction_ring_buffer[marked_for_destruction_index];
+    }
+
+    Core::System& system;
+
+    std::unique_ptr<StreamBuffer> stream_buffer;
+    BufferType stream_buffer_handle{};
+
+    bool invalidated = false;
+
+    u8* buffer_ptr = nullptr;
+    u64 buffer_offset = 0;
+    u64 buffer_offset_base = 0;
+
+    std::size_t marked_for_destruction_index = 0;
+    std::array<std::vector<BufferStorageType>, 4> marked_for_destruction_ring_buffer;
+
+    std::unordered_set<CacheAddr> internalized_entries;
+    std::unordered_map<CacheAddr, std::vector<Buffer>> buffer_reserve;
+};
+
+} // namespace VideoCommon