Vulkan: Improve copy buffer self-dependency

src/libANGLE/renderer/vulkan/BufferVk.cpp

@@ -156,16 +156,28 @@ angle::Result BufferVk::copySubData(const gl::Context *context,
     auto *sourceBuffer   = GetAs<BufferVk>(source);
 
     vk::CommandBuffer *commandBuffer = nullptr;
-    ANGLE_TRY(mBuffer.recordCommands(contextVk, &commandBuffer));
+
+    // Handle self-dependency especially.
+    if (sourceBuffer->mBuffer.getBuffer().getHandle() == mBuffer.getBuffer().getHandle())
+    {
+        mBuffer.onSelfReadWrite(contextVk, VK_ACCESS_TRANSFER_READ_BIT,
+                                VK_ACCESS_TRANSFER_WRITE_BIT);
+
+        ANGLE_TRY(mBuffer.recordCommands(contextVk, &commandBuffer));
+    }
+    else
+    {
+        ANGLE_TRY(mBuffer.recordCommands(contextVk, &commandBuffer));
+
+        sourceBuffer->mBuffer.onRead(&mBuffer, VK_ACCESS_TRANSFER_READ_BIT);
+        mBuffer.onWrite(contextVk, VK_ACCESS_TRANSFER_WRITE_BIT);
+    }
 
     // Enqueue a copy command on the GPU.
     VkBufferCopy copyRegion = {static_cast<VkDeviceSize>(sourceOffset),
                                static_cast<VkDeviceSize>(destOffset),
                                static_cast<VkDeviceSize>(size)};
 
-    sourceBuffer->mBuffer.onRead(&mBuffer, VK_ACCESS_TRANSFER_READ_BIT);
-    mBuffer.onWrite(contextVk, VK_ACCESS_TRANSFER_WRITE_BIT);
-
     commandBuffer->copyBuffer(sourceBuffer->getBuffer().getBuffer(), mBuffer.getBuffer(), 1,
                               &copyRegion);
 

src/libANGLE/renderer/vulkan/CommandGraph.cpp

@@ -275,7 +275,7 @@ void CommandGraphResource::addReadDependency(CommandGraphResource *readingResour
     CommandGraphNode *readingNode = readingResource->mCurrentWritingNode;
     ASSERT(readingNode);
 
-    if (mCurrentWritingNode && (mCurrentWritingNode != readingNode))
+    if (mCurrentWritingNode)
     {
         // Ensure 'readingNode' happens after the current writing node.
         CommandGraphNode::SetHappensBeforeDependency(mCurrentWritingNode, readingNode);

src/libANGLE/renderer/vulkan/vk_helpers.cpp

@@ -1237,6 +1237,21 @@ void BufferHelper::onWrite(ContextVk *contextVk, VkAccessFlags writeAccessType)
     }
 }
 
+void BufferHelper::onSelfReadWrite(ContextVk *contextVk,
+                                   VkAccessFlags readAccessType,
+                                   VkAccessFlags writeAccessType)
+{
+    if (mCurrentReadAccess || mCurrentWriteAccess)
+    {
+        finishCurrentCommands(contextVk);
+        addGlobalMemoryBarrier(mCurrentReadAccess | mCurrentWriteAccess,
+                               readAccessType | writeAccessType);
+    }
+
+    mCurrentReadAccess  = readAccessType;
+    mCurrentWriteAccess = writeAccessType;
+}
+
 angle::Result BufferHelper::copyFromBuffer(ContextVk *contextVk,
                                            const Buffer &buffer,
                                            VkAccessFlags bufferAccessType,

src/libANGLE/renderer/vulkan/vk_helpers.h

@@ -446,6 +446,9 @@ class BufferHelper final : public CommandGraphResource
     }
 
     void onWrite(ContextVk *contextVk, VkAccessFlags writeAccessType);
+    void onSelfReadWrite(ContextVk *contextVk,
+                         VkAccessFlags readAccessType,
+                         VkAccessFlags writeAccessType);
 
     // Also implicitly sets up the correct barriers.
     angle::Result copyFromBuffer(ContextVk *contextVk,