Vulkan: Optimize Attribute Change Perf (3/5)

This patch series optimizes programs that use the pattern:

for (;;) {
  glVertexAttribPointer(...)
  glDraw(...)
}

Change 3: Use FastUnorderedSet for RP XFB buffers.

Most of the time this list is empty. This speeds up the count check for
empty and non-empty sets considerably.

In total the patch series reduces test iteration time by 25%.

Test: DrawCallPerfBenchmark.Run/vulkan_attrib_change
Bug: angleproject:5045
Bug: b/168493024
Change-Id: Ia43eb11bdd62aa3bf425069b591f9318f519fd4c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2409175
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -3460,7 +3460,7 @@ angle::Result ContextVk::onBeginTransformFeedback(
     for (size_t bufferIndex = 0; bufferIndex < bufferCount; ++bufferIndex)
     {
         const vk::BufferHelper *buffer = buffers[bufferIndex];
-        if (mCurrentTransformFeedbackBuffers.count(buffer) != 0 ||
+        if (mCurrentTransformFeedbackBuffers.contains(buffer) ||
             mRenderPassCommands->usesBuffer(*buffer))
         {
             ANGLE_TRY(flushCommandsAndEndRenderPass());
@@ -3484,7 +3484,11 @@ void ContextVk::populateTransformFeedbackBufferSet(
 {
     for (size_t bufferIndex = 0; bufferIndex < bufferCount; ++bufferIndex)
     {
-        mCurrentTransformFeedbackBuffers.insert(buffers[bufferIndex]);
+        vk::BufferHelper *buffer = buffers[bufferIndex];
+        if (!mCurrentTransformFeedbackBuffers.contains(buffer))
+        {
+            mCurrentTransformFeedbackBuffers.insert(buffer);
+        }
     }
 }
 

src/libANGLE/renderer/vulkan/ContextVk.h

@@ -1063,7 +1063,9 @@ class ContextVk : public ContextImpl, public vk::Context
     bool mHasPrimaryCommands;
 
     // Transform feedback buffers.
-    std::unordered_set<const vk::BufferHelper *> mCurrentTransformFeedbackBuffers;
+    angle::FastUnorderedSet<const vk::BufferHelper *,
+                            gl::IMPLEMENTATION_MAX_TRANSFORM_FEEDBACK_BUFFERS>
+        mCurrentTransformFeedbackBuffers;
 
     // Internal shader library.
     vk::ShaderLibrary mShaderLibrary;
@@ -1131,7 +1133,7 @@ class ContextVk : public ContextImpl, public vk::Context
 ANGLE_INLINE angle::Result ContextVk::endRenderPassIfTransformFeedbackBuffer(
     const vk::BufferHelper *buffer)
 {
-    if (!buffer || mCurrentTransformFeedbackBuffers.count(buffer) == 0)
+    if (!buffer || !mCurrentTransformFeedbackBuffers.contains(buffer))
     {
         return angle::Result::Continue;
     }