2 files changed, 496 insertions, 0 deletions

diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index f7b9d7f86..c3d0f4c31 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_subdirectory(host_shaders)
 
 add_library(video_core STATIC
+    buffer_cache/buffer_base.h
     buffer_cache/buffer_block.h
     buffer_cache/buffer_cache.h
     buffer_cache/map_interval.cpp
diff --git a/src/video_core/buffer_cache/buffer_base.h b/src/video_core/buffer_cache/buffer_base.h
new file mode 100644
index 000000000..fd740c2c1
--- /dev/null
+++ b/src/video_core/buffer_cache/buffer_base.h
@@ -0,0 +1,495 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <algorithm>
+#include <bit>
+#include <limits>
+#include <utility>
+
+#include "common/alignment.h"
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+#include "common/div_ceil.h"
+#include "core/memory.h"
+
+namespace VideoCommon {
+
+enum class BufferFlagBits {
+    Picked = 1 << 0,
+};
+DECLARE_ENUM_FLAG_OPERATORS(BufferFlagBits)
+
+/// Tag for creating null buffers with no storage or size
+struct NullBufferParams {};
+
+/**
+ * Range tracking buffer container.
+ *
+ * It keeps track of the modified CPU and GPU ranges on a CPU page granularity, notifying the given
+ * rasterizer about state changes in the tracking behavior of the buffer.
+ *
+ * The buffer size and address is forcefully aligned to CPU page boundaries.
+ */
+template <class RasterizerInterface>
+class BufferBase {
+    static constexpr u64 PAGES_PER_WORD = 64;
+    static constexpr u64 BYTES_PER_PAGE = Core::Memory::PAGE_SIZE;
+    static constexpr u64 BYTES_PER_WORD = PAGES_PER_WORD * BYTES_PER_PAGE;
+
+    /// Vector tracking modified pages tightly packed with small vector optimization
+    union WrittenWords {
+        /// Returns the pointer to the words state
+        [[nodiscard]] const u64* Pointer(bool is_short) const noexcept {
+            return is_short ? &stack : heap;
+        }
+
+        /// Returns the pointer to the words state
+        [[nodiscard]] u64* Pointer(bool is_short) noexcept {
+            return is_short ? &stack : heap;
+        }
+
+        u64 stack = 0; ///< Small buffers storage
+        u64* heap;     ///< Not-small buffers pointer to the storage
+    };
+
+    struct GpuCpuWords {
+        explicit GpuCpuWords() = default;
+        explicit GpuCpuWords(u64 size_bytes_) : size_bytes{size_bytes_} {
+            if (IsShort()) {
+                cpu.stack = ~u64{0};
+                gpu.stack = 0;
+            } else {
+                // Share allocation between CPU and GPU pages and set their default values
+                const size_t num_words = NumWords();
+                u64* const alloc = new u64[num_words * 2];
+                cpu.heap = alloc;
+                gpu.heap = alloc + num_words;
+                std::fill_n(cpu.heap, num_words, ~u64{0});
+                std::fill_n(gpu.heap, num_words, 0);
+            }
+            // Clean up tailing bits
+            const u64 last_local_page =
+                Common::DivCeil(size_bytes % BYTES_PER_WORD, BYTES_PER_PAGE);
+            const u64 shift = (PAGES_PER_WORD - last_local_page) % PAGES_PER_WORD;
+            u64& last_word = cpu.Pointer(IsShort())[NumWords() - 1];
+            last_word = (last_word << shift) >> shift;
+        }
+
+        ~GpuCpuWords() {
+            Release();
+        }
+
+        GpuCpuWords& operator=(GpuCpuWords&& rhs) noexcept {
+            Release();
+            size_bytes = rhs.size_bytes;
+            cpu = rhs.cpu;
+            gpu = rhs.gpu;
+            rhs.cpu.heap = nullptr;
+            return *this;
+        }
+
+        GpuCpuWords(GpuCpuWords&& rhs) noexcept
+            : size_bytes{rhs.size_bytes}, cpu{rhs.cpu}, gpu{rhs.gpu} {
+            rhs.cpu.heap = nullptr;
+        }
+
+        GpuCpuWords& operator=(const GpuCpuWords&) = delete;
+        GpuCpuWords(const GpuCpuWords&) = delete;
+
+        /// Returns true when the buffer fits in the small vector optimization
+        [[nodiscard]] bool IsShort() const noexcept {
+            return size_bytes <= BYTES_PER_WORD;
+        }
+
+        /// Returns the number of words of the buffer
+        [[nodiscard]] size_t NumWords() const noexcept {
+            return Common::DivCeil(size_bytes, BYTES_PER_WORD);
+        }
+
+        /// Release buffer resources
+        void Release() {
+            if (!IsShort()) {
+                // CPU written words is the base for the heap allocation
+                delete[] cpu.heap;
+            }
+        }
+
+        u64 size_bytes = 0;
+        WrittenWords cpu;
+        WrittenWords gpu;
+    };
+
+public:
+    explicit BufferBase(RasterizerInterface& rasterizer_, VAddr cpu_addr_, u64 size_bytes)
+        : rasterizer{&rasterizer_}, cpu_addr{Common::AlignDown(cpu_addr_, BYTES_PER_PAGE)},
+          words(Common::AlignUp(size_bytes + (cpu_addr_ - cpu_addr), BYTES_PER_PAGE)) {}
+
+    explicit BufferBase(NullBufferParams) {}
+
+    BufferBase& operator=(const BufferBase&) = delete;
+    BufferBase(const BufferBase&) = delete;
+
+    /// Returns the inclusive CPU modified range in a begin end pair
+    [[nodiscard]] std::pair<u64, u64> ModifiedCpuRegion(VAddr query_cpu_addr,
+                                                        u64 query_size) const noexcept {
+        const u64 offset = query_cpu_addr - cpu_addr;
+        return ModifiedRegion<false>(offset, query_size);
+    }
+
+    /// Returns the inclusive GPU modified range in a begin end pair
+    [[nodiscard]] std::pair<u64, u64> ModifiedGpuRegion(VAddr query_cpu_addr,
+                                                        u64 query_size) const noexcept {
+        const u64 offset = query_cpu_addr - cpu_addr;
+        return ModifiedRegion<true>(offset, query_size);
+    }
+
+    /// Returns true if a region has been modified from the CPU
+    [[nodiscard]] bool IsRegionCpuModified(VAddr query_cpu_addr, u64 query_size) const noexcept {
+        const u64 offset = query_cpu_addr - cpu_addr;
+        return IsRegionModified<false>(offset, query_size);
+    }
+
+    /// Returns true if a region has been modified from the GPU
+    [[nodiscard]] bool IsRegionGpuModified(VAddr query_cpu_addr, u64 query_size) const noexcept {
+        const u64 offset = query_cpu_addr - cpu_addr;
+        return IsRegionModified<true>(offset, query_size);
+    }
+
+    /// Mark region as CPU modified, notifying the rasterizer about this change
+    void MarkRegionAsCpuModified(VAddr dirty_cpu_addr, u64 size) {
+        ChangeRegionState<true, true>(words.cpu, dirty_cpu_addr, size);
+    }
+
+    /// Unmark region as CPU modified, notifying the rasterizer about this change
+    void UnmarkRegionAsCpuModified(VAddr dirty_cpu_addr, u64 size) {
+        ChangeRegionState<false, true>(words.cpu, dirty_cpu_addr, size);
+    }
+
+    /// Mark region as modified from the host GPU
+    void MarkRegionAsGpuModified(VAddr dirty_cpu_addr, u64 size) noexcept {
+        ChangeRegionState<true, false>(words.gpu, dirty_cpu_addr, size);
+    }
+
+    /// Unmark region as modified from the host GPU
+    void UnmarkRegionAsGpuModified(VAddr dirty_cpu_addr, u64 size) noexcept {
+        ChangeRegionState<false, false>(words.gpu, dirty_cpu_addr, size);
+    }
+
+    /// Call 'func' for each CPU modified range and unmark those pages as CPU modified
+    template <typename Func>
+    void ForEachUploadRange(VAddr query_cpu_range, u64 size, Func&& func) {
+        ForEachModifiedRange<false, true>(query_cpu_range, size, func);
+    }
+
+    /// Call 'func' for each GPU modified range and unmark those pages as GPU modified
+    template <typename Func>
+    void ForEachDownloadRange(VAddr query_cpu_range, u64 size, Func&& func) {
+        ForEachModifiedRange<true, false>(query_cpu_range, size, func);
+    }
+
+    /// Call 'func' for each GPU modified range and unmark those pages as GPU modified
+    template <typename Func>
+    void ForEachDownloadRange(Func&& func) {
+        ForEachModifiedRange<true, false>(cpu_addr, SizeBytes(), func);
+    }
+
+    /// Mark buffer as picked
+    void Pick() noexcept {
+        flags |= BufferFlagBits::Picked;
+    }
+
+    /// Unmark buffer as picked
+    void Unpick() noexcept {
+        flags &= ~BufferFlagBits::Picked;
+    }
+
+    /// Returns true when vaddr -> vaddr+size is fully contained in the buffer
+    [[nodiscard]] bool IsInBounds(VAddr addr, u64 size) const noexcept {
+        return addr >= cpu_addr && addr + size <= cpu_addr + SizeBytes();
+    }
+
+    /// Returns true if the buffer has been marked as picked
+    [[nodiscard]] bool IsPicked() const noexcept {
+        return True(flags & BufferFlagBits::Picked);
+    }
+
+    /// Returns the base CPU address of the buffer
+    [[nodiscard]] VAddr CpuAddr() const noexcept {
+        return cpu_addr;
+    }
+
+    /// Returns the offset relative to the given CPU address
+    /// @pre IsInBounds returns true
+    [[nodiscard]] u32 Offset(VAddr other_cpu_addr) const noexcept {
+        return static_cast<u32>(other_cpu_addr - cpu_addr);
+    }
+
+    /// Returns the size in bytes of the buffer
+    [[nodiscard]] u64 SizeBytes() const noexcept {
+        return words.size_bytes;
+    }
+
+private:
+    /**
+     * Change the state of a range of pages
+     *
+     * @param written_words Pages to be marked or unmarked as modified
+     * @param dirty_addr    Base address to mark or unmark as modified
+     * @param size          Size in bytes to mark or unmark as modified
+     *
+     * @tparam enable            True when the bits will be set to one, false for zero
+     * @tparam notify_rasterizer True when the rasterizer has to be notified about the changes
+     */
+    template <bool enable, bool notify_rasterizer>
+    void ChangeRegionState(WrittenWords& written_words, u64 dirty_addr,
+                           s64 size) noexcept(!notify_rasterizer) {
+        const s64 difference = dirty_addr - cpu_addr;
+        const u64 offset = std::max<s64>(difference, 0);
+        size += std::min<s64>(difference, 0);
+        if (offset >= SizeBytes() || size < 0) {
+            return;
+        }
+        u64* const state_words = written_words.Pointer(IsShort());
+        const u64 offset_end = std::min(offset + size, SizeBytes());
+        const u64 begin_page_index = offset / BYTES_PER_PAGE;
+        const u64 begin_word_index = begin_page_index / PAGES_PER_WORD;
+        const u64 end_page_index = Common::DivCeil(offset_end, BYTES_PER_PAGE);
+        const u64 end_word_index = Common::DivCeil(end_page_index, PAGES_PER_WORD);
+        u64 page_index = begin_page_index % PAGES_PER_WORD;
+        u64 word_index = begin_word_index;
+        while (word_index < end_word_index) {
+            const u64 next_word_first_page = (word_index + 1) * PAGES_PER_WORD;
+            const u64 left_offset =
+                std::min(next_word_first_page - end_page_index, PAGES_PER_WORD) % PAGES_PER_WORD;
+            const u64 right_offset = page_index;
+            u64 bits = ~u64{0};
+            bits = (bits >> right_offset) << right_offset;
+            bits = (bits << left_offset) >> left_offset;
+            if constexpr (notify_rasterizer) {
+                NotifyRasterizer<!enable>(word_index, state_words[word_index], bits);
+            }
+            if constexpr (enable) {
+                state_words[word_index] |= bits;
+            } else {
+                state_words[word_index] &= ~bits;
+            }
+            page_index = 0;
+            ++word_index;
+        }
+    }
+
+    /**
+     * Notify rasterizer about changes in the CPU tracking state of a word in the buffer
+     *
+     * @param word_index   Index to the word to notify to the rasterizer
+     * @param current_bits Current state of the word
+     * @param new_bits     New state of the word
+     *
+     * @tparam add_to_rasterizer True when the rasterizer should start tracking the new pages
+     */
+    template <bool add_to_rasterizer>
+    void NotifyRasterizer(u64 word_index, u64 current_bits, u64 new_bits) {
+        u64 changed_bits = (add_to_rasterizer ? current_bits : ~current_bits) & new_bits;
+        VAddr addr = cpu_addr + word_index * BYTES_PER_WORD;
+        while (changed_bits != 0) {
+            const int empty_bits = std::countr_zero(changed_bits);
+            addr += empty_bits * BYTES_PER_PAGE;
+            changed_bits >>= empty_bits;
+
+            const u32 continuous_bits = std::countr_one(changed_bits);
+            const u64 size = continuous_bits * BYTES_PER_PAGE;
+            const VAddr begin_addr = addr;
+            addr += size;
+            changed_bits = continuous_bits < PAGES_PER_WORD ? (changed_bits >> continuous_bits) : 0;
+            rasterizer->UpdatePagesCachedCount(begin_addr, size, add_to_rasterizer ? 1 : -1);
+        }
+    }
+
+    /**
+     * Loop over each page in the given range, turn off those bits and notify the rasterizer if
+     * needed. Call the given function on each turned off range.
+     *
+     * @param query_cpu_range Base CPU address to loop over
+     * @param size            Size in bytes of the CPU range to loop over
+     * @param func            Function to call for each turned off region
+     *
+     * @tparam gpu               True for host GPU pages, false for CPU pages
+     * @tparam notify_rasterizer True when the rasterizer should be notified about state changes
+     */
+    template <bool gpu, bool notify_rasterizer, typename Func>
+    void ForEachModifiedRange(VAddr query_cpu_range, s64 size, Func&& func) {
+        const s64 difference = query_cpu_range - cpu_addr;
+        const u64 query_begin = std::max<s64>(difference, 0);
+        size += std::min<s64>(difference, 0);
+        if (query_begin >= SizeBytes() || size < 0) {
+            return;
+        }
+        const u64* const cpu_words = words.cpu.Pointer(IsShort());
+        const u64 query_end = query_begin + std::min(static_cast<u64>(size), SizeBytes());
+        u64* const state_words = (gpu ? words.gpu : words.cpu).Pointer(IsShort());
+        u64* const words_begin = state_words + query_begin / BYTES_PER_WORD;
+        u64* const words_end = state_words + Common::DivCeil(query_end, BYTES_PER_WORD);
+
+        const auto modified = [](u64 word) { return word != 0; };
+        const auto first_modified_word = std::find_if(words_begin, words_end, modified);
+        if (first_modified_word == words_end) {
+            // Exit early when the buffer is not modified
+            return;
+        }
+        const auto last_modified_word = std::find_if_not(first_modified_word, words_end, modified);
+
+        const u64 word_index_begin = std::distance(state_words, first_modified_word);
+        const u64 word_index_end = std::distance(state_words, last_modified_word);
+
+        const unsigned local_page_begin = std::countr_zero(*first_modified_word);
+        const unsigned local_page_end = PAGES_PER_WORD - std::countl_zero(last_modified_word[-1]);
+        const u64 word_page_begin = word_index_begin * PAGES_PER_WORD;
+        const u64 word_page_end = (word_index_end - 1) * PAGES_PER_WORD;
+        const u64 query_page_begin = query_begin / BYTES_PER_PAGE;
+        const u64 query_page_end = Common::DivCeil(query_end, BYTES_PER_PAGE);
+        const u64 page_index_begin = std::max(word_page_begin + local_page_begin, query_page_begin);
+        const u64 page_index_end = std::min(word_page_end + local_page_end, query_page_end);
+        const u64 first_word_page_begin = page_index_begin % PAGES_PER_WORD;
+        const u64 last_word_page_end = (page_index_end - 1) % PAGES_PER_WORD + 1;
+
+        u64 page_begin = first_word_page_begin;
+        u64 current_base = 0;
+        u64 current_size = 0;
+        bool on_going = false;
+        for (u64 word_index = word_index_begin; word_index < word_index_end; ++word_index) {
+            const bool is_last_word = word_index + 1 == word_index_end;
+            const u64 page_end = is_last_word ? last_word_page_end : PAGES_PER_WORD;
+            const u64 right_offset = page_begin;
+            const u64 left_offset = PAGES_PER_WORD - page_end;
+            u64 bits = ~u64{0};
+            bits = (bits >> right_offset) << right_offset;
+            bits = (bits << left_offset) >> left_offset;
+
+            const u64 current_word = state_words[word_index] & bits;
+            state_words[word_index] &= ~bits;
+
+            // Exclude CPU modified pages when visiting GPU pages
+            const u64 word = current_word & ~(gpu ? cpu_words[word_index] : 0);
+            if constexpr (notify_rasterizer) {
+                NotifyRasterizer<true>(word_index, word, ~u64{0});
+            }
+            u64 page = page_begin;
+            page_begin = 0;
+
+            while (page < page_end) {
+                const int empty_bits = std::countr_zero(word >> page);
+                if (on_going && empty_bits != 0) {
+                    InvokeModifiedRange(func, current_size, current_base);
+                    current_size = 0;
+                    on_going = false;
+                }
+                page += empty_bits;
+
+                const int continuous_bits = std::countr_one(word >> page);
+                if (!on_going && continuous_bits != 0) {
+                    current_base = word_index * PAGES_PER_WORD + page;
+                    on_going = true;
+                }
+                current_size += continuous_bits;
+                page += continuous_bits;
+            }
+        }
+        if (on_going && current_size > 0) {
+            InvokeModifiedRange(func, current_size, current_base);
+        }
+    }
+
+    template <typename Func>
+    void InvokeModifiedRange(Func&& func, u64 current_size, u64 current_base) {
+        const u64 current_size_bytes = current_size * BYTES_PER_PAGE;
+        const u64 offset_begin = current_base * BYTES_PER_PAGE;
+        const u64 offset_end = std::min(offset_begin + current_size_bytes, SizeBytes());
+        func(offset_begin, offset_end - offset_begin);
+    }
+
+    /**
+     * Returns true when a region has been modified
+     *
+     * @param offset Offset in bytes from the start of the buffer
+     * @param size   Size in bytes of the region to query for modifications
+     */
+    template <bool gpu>
+    [[nodiscard]] bool IsRegionModified(u64 offset, u64 size) const noexcept {
+        const u64* const cpu_words = words.cpu.Pointer(IsShort());
+        const u64* const state_words = (gpu ? words.gpu : words.cpu).Pointer(IsShort());
+        const u64 num_query_words = size / BYTES_PER_WORD + 1;
+        const u64 word_begin = offset / BYTES_PER_WORD;
+        const u64 word_end = std::min(word_begin + num_query_words, NumWords());
+        const u64 page_limit = Common::DivCeil(offset + size, BYTES_PER_PAGE);
+        u64 page_index = (offset / BYTES_PER_PAGE) % PAGES_PER_WORD;
+        for (u64 word_index = word_begin; word_index < word_end; ++word_index, page_index = 0) {
+            const u64 word = state_words[word_index] & ~(gpu ? cpu_words[word_index] : 0);
+            if (word == 0) {
+                continue;
+            }
+            const u64 page_end = std::min((word_index + 1) * PAGES_PER_WORD, page_limit);
+            const u64 local_page_end = page_end % PAGES_PER_WORD;
+            const u64 page_end_shift = (PAGES_PER_WORD - local_page_end) % PAGES_PER_WORD;
+            if (((word >> page_index) << page_index) << page_end_shift != 0) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns a begin end pair with the inclusive modified region
+     *
+     * @param offset Offset in bytes from the start of the buffer
+     * @param size   Size in bytes of the region to query for modifications
+     *
+     * @tparam True to query GPU modified pages, false for CPU pages
+     */
+    template <bool gpu>
+    [[nodiscard]] std::pair<u64, u64> ModifiedRegion(u64 offset, u64 size) const noexcept {
+        const u64* const cpu_words = words.cpu.Pointer(IsShort());
+        const u64* const state_words = (gpu ? words.gpu : words.cpu).Pointer(IsShort());
+        const u64 num_query_words = size / BYTES_PER_WORD + 1;
+        const u64 word_begin = offset / BYTES_PER_WORD;
+        const u64 word_end = std::min(word_begin + num_query_words, NumWords());
+        const u64 page_base = offset / BYTES_PER_PAGE;
+        const u64 page_limit = Common::DivCeil(offset + size, BYTES_PER_PAGE);
+        u64 begin = std::numeric_limits<u64>::max();
+        u64 end = 0;
+        for (u64 word_index = word_begin; word_index < word_end; ++word_index) {
+            const u64 word = state_words[word_index] & ~(gpu ? cpu_words[word_index] : 0);
+            if (word == 0) {
+                continue;
+            }
+            const u64 local_page_begin = std::countr_zero(word);
+            const u64 local_page_end = PAGES_PER_WORD - std::countl_zero(word);
+            const u64 page_index = word_index * PAGES_PER_WORD;
+            const u64 page_begin = std::max(page_index + local_page_begin, page_base);
+            const u64 page_end = std::min(page_index + local_page_end, page_limit);
+            begin = std::min(begin, page_begin);
+            end = std::max(end, page_end);
+        }
+        static constexpr std::pair<u64, u64> EMPTY{0, 0};
+        return begin < end ? std::make_pair(begin * BYTES_PER_PAGE, end * BYTES_PER_PAGE) : EMPTY;
+    }
+
+    /// Returns the number of words of the buffer
+    [[nodiscard]] size_t NumWords() const noexcept {
+        return words.NumWords();
+    }
+
+    /// Returns true when the buffer fits in the small vector optimization
+    [[nodiscard]] bool IsShort() const noexcept {
+        return words.IsShort();
+    }
+
+    RasterizerInterface* rasterizer = nullptr;
+    VAddr cpu_addr = 0;
+    GpuCpuWords words;
+    BufferFlagBits flags{};
+};
+
+} // namespace VideoCommon