Vulkan: Optimize resource tracking in CommandBufferHelper.

src/common/FastVector.h

@@ -212,9 +212,8 @@ ANGLE_INLINE typename FastVector<T, N, Storage>::reference FastVector<T, N, Stor
 }
 
 template <class T, size_t N, class Storage>
-ANGLE_INLINE
-    typename FastVector<T, N, Storage>::const_reference FastVector<T, N, Storage>::operator[](
-        size_type pos) const
+ANGLE_INLINE typename FastVector<T, N, Storage>::const_reference
+FastVector<T, N, Storage>::operator[](size_type pos) const
 {
     ASSERT(pos < mSize);
     return mData[pos];
@@ -427,6 +426,54 @@ void FastVector<T, N, Storage>::ensure_capacity(size_t capacity)
         mReservedSize = newSize;
     }
 }
+
+template <class Key, class Value, size_t N>
+class FastUnorderedMap final
+{
+  public:
+    using Pair = std::pair<Key, Value>;
+
+    FastUnorderedMap() {}
+    ~FastUnorderedMap() {}
+
+    void insert(Key key, Value value)
+    {
+        ASSERT(!contains(key));
+        mData.push_back(Pair(key, value));
+    }
+
+    bool contains(Key key) const
+    {
+        for (size_t index = 0; index < mData.size(); ++index)
+        {
+            if (mData[index].first == key)
+                return true;
+        }
+        return false;
+    }
+
+    void clear() { mData.clear(); }
+
+    bool get(Key key, Value *value) const
+    {
+        for (size_t index = 0; index < mData.size(); ++index)
+        {
+            const Pair &item = mData[index];
+            if (item.first == key)
+            {
+                *value = item.second;
+                return true;
+            }
+        }
+        return false;
+    }
+
+    bool empty() const { return mData.empty(); }
+
+  private:
+    FastVector<Pair, N> mData;
+};
+
 }  // namespace angle
 
 #endif  // COMMON_FASTVECTOR_H_

src/common/FastVector_unittest.cpp

@@ -233,4 +233,35 @@ TEST(FastVector, NonCopyable)
     EXPECT_EQ(1u, copy.size());
     EXPECT_EQ(3, copy[0].x);
 }
+
+// Basic functionality for FastUnorderedMap
+TEST(FastUnorderedMap, BasicUsage)
+{
+    FastUnorderedMap<int, bool, 3> testMap;
+    EXPECT_TRUE(testMap.empty());
+
+    testMap.insert(5, true);
+    EXPECT_TRUE(testMap.contains(5));
+
+    bool value = false;
+    EXPECT_TRUE(testMap.get(5, &value));
+    EXPECT_TRUE(value);
+    EXPECT_FALSE(testMap.get(6, &value));
+
+    EXPECT_FALSE(testMap.empty());
+    testMap.clear();
+    EXPECT_TRUE(testMap.empty());
+
+    for (int i = 0; i < 10; ++i)
+    {
+        testMap.insert(i, false);
+    }
+
+    for (int i = 0; i < 10; ++i)
+    {
+        EXPECT_TRUE(testMap.contains(i));
+        EXPECT_TRUE(testMap.get(i, &value));
+        EXPECT_FALSE(value);
+    }
+}
 }  // namespace angle

src/libANGLE/renderer/vulkan/vk_helpers.cpp

@@ -569,13 +569,17 @@ void CommandBufferHelper::initialize(bool isRenderPassCommandBuffer, bool mergeB
 
 bool CommandBufferHelper::usesBuffer(const BufferHelper &buffer) const
 {
-    return mUsedBuffers.count(buffer.getBufferSerial()) > 0;
+    return mUsedBuffers.contains(buffer.getBufferSerial());
 }
 
 bool CommandBufferHelper::usesBufferForWrite(const BufferHelper &buffer) const
 {
-    auto iter = mUsedBuffers.find(buffer.getBufferSerial());
-    return iter != mUsedBuffers.end() && iter->second == BufferAccess::Write;
+    BufferAccess access;
+    if (!mUsedBuffers.get(buffer.getBufferSerial(), &access))
+    {
+        return false;
+    }
+    return access == BufferAccess::Write;
 }
 
 void CommandBufferHelper::bufferRead(ResourceUseList *resourceUseList,
@@ -591,7 +595,10 @@ void CommandBufferHelper::bufferRead(ResourceUseList *resourceUseList,
     }
 
     ASSERT(!usesBufferForWrite(*buffer));
-    mUsedBuffers[buffer->getBufferSerial()] = BufferAccess::Read;
+    if (!mUsedBuffers.contains(buffer->getBufferSerial()))
+    {
+        mUsedBuffers.insert(buffer->getBufferSerial(), BufferAccess::Read);
+    }
 }
 
 void CommandBufferHelper::bufferWrite(ResourceUseList *resourceUseList,
@@ -614,7 +621,7 @@ void CommandBufferHelper::bufferWrite(ResourceUseList *resourceUseList,
     if (aliasingMode == BufferAliasingMode::Disallowed)
     {
         ASSERT(!usesBuffer(*buffer));
-        mUsedBuffers[buffer->getBufferSerial()] = BufferAccess::Write;
+        mUsedBuffers.insert(buffer->getBufferSerial(), BufferAccess::Write);
     }
 }
 

src/libANGLE/renderer/vulkan/vk_helpers.h

@@ -1011,7 +1011,8 @@ struct CommandBufferHelper : angle::NonCopyable
     uint32_t mDepthStencilAttachmentIndex;
 
     // Tracks resources used in the command buffer.
-    std::unordered_map<BufferSerial, BufferAccess> mUsedBuffers;
+    static constexpr uint32_t kFastMapSize = 8;
+    angle::FastUnorderedMap<BufferSerial, BufferAccess, kFastMapSize> mUsedBuffers;
 };
 
 static constexpr uint32_t kInvalidAttachmentIndex = -1;