From 6ea97833a636247bc137ee6d24efd0ac7a68111d Mon Sep 17 00:00:00 2001
From: Shrek Shao <[email protected]>
Date: Wed, 20 May 2026 11:06:10 -0700
Subject: [PATCH] Remove the optimization of a clearing buffer in BlitTextureToBuffer

This optimization is temporarily removed because we cannot mark
the buffer as initialized until the command buffer is submitted.

FIXED: 513631768
Change-Id: Ie6f539e07139c5eefef9ddf87231af346d7a9e28
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/309588
Auto-Submit: Shrek Shao <[email protected]>
Reviewed-by: Loko Kung <[email protected]>
Commit-Queue: Shrek Shao <[email protected]>
---

diff --git a/src/dawn/native/BlitTextureToBuffer.cpp b/src/dawn/native/BlitTextureToBuffer.cpp
index 22fa7f2..b663bfc 100644
--- a/src/dawn/native/BlitTextureToBuffer.cpp
+++ b/src/dawn/native/BlitTextureToBuffer.cpp
@@ -1354,8 +1354,11 @@
                                                          UsageValidationMode::Internal));
     }
 
-    // Skip clearing the buffer if this is full size copy.
-    dst.buffer->SetInitialized(fullSizeCopy || dst.buffer->IsInitialized());
+    // TODO(b/513631768): Skip clearing the buffer if this is full size copy.
+    // dst.buffer->SetInitialized(fullSizeCopy || dst.buffer->IsInitialized());
+    //
+    // This optimization is temporarily removed because we cannot mark the buffer as initialized
+    // until the command buffer is submitted.
 
     Ref<ComputePassEncoder> pass = commandEncoder->BeginComputePass();
     pass->APISetPipeline(pipeline.Get());
diff --git a/src/dawn/tests/end2end/BufferZeroInitTests.cpp b/src/dawn/tests/end2end/BufferZeroInitTests.cpp
index 6d86a10..625446a 100644
--- a/src/dawn/tests/end2end/BufferZeroInitTests.cpp
+++ b/src/dawn/tests/end2end/BufferZeroInitTests.cpp
@@ -145,7 +145,14 @@
         wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
         encoder.CopyTextureToBuffer(&texelCopyTextureInfo, &texelCopyBufferInfo, &spec.textureSize);
         wgpu::CommandBuffer commandBuffer = encoder.Finish();
-        EXPECT_LAZY_CLEAR(spec.lazyClearCount, queue.Submit(1, &commandBuffer));
+
+        // TODO(b/513631768): SetInitialized is now skipped for use_blit_for_t2b path.
+        uint32_t expectedLazyClearCount = spec.lazyClearCount;
+        if (expectedLazyClearCount == 0u && (HasToggleEnabled("use_blit_for_t2b"))) {
+            expectedLazyClearCount = 1u;
+        }
+
+        EXPECT_LAZY_CLEAR(expectedLazyClearCount, queue.Submit(1, &commandBuffer));
 
         const uint64_t expectedValueCount = bufferSize / sizeof(float);
         std::vector<float> expectedValues(expectedValueCount, 0.f);
@@ -1153,6 +1160,10 @@
     // TODO(crbug.com/473593119): [Capture] size not multiple of 4.
     DAWN_SUPPRESS_TEST_IF(IsCaptureReplayCheckingEnabled());
 
+    // TODO(crbug.com/513631768): Skip D3D11 as they may use intermediate buffer for blit
+    // path and fail for EXPECT_LAZY_CLEAR.
+    DAWN_SUPPRESS_TEST_IF(IsD3D11());
+
     constexpr wgpu::TextureFormat kColorAttachmentFormat = wgpu::TextureFormat::RGBA8Unorm;
     // A small sub-4-byte format means a single vertex can fit entirely within the padded buffer,
     // touching some of the padding. Test a small format, as well as larger formats.
@@ -1222,7 +1233,13 @@
                     encoder.CopyTextureToBuffer(&zeroTextureSrc, &dst, &extent);
 
                     wgpu::CommandBuffer commandBuffer = encoder.Finish();
-                    EXPECT_LAZY_CLEAR(0u, queue.Submit(1, &commandBuffer));
+
+                    // TODO(b/513631768): SetInitialized is now skipped for use_blit_for_t2b path.
+                    uint32_t expectedLazyClearCount = 0u;
+                    if (HasToggleEnabled("use_blit_for_t2b")) {
+                        expectedLazyClearCount = 1u;
+                    }
+                    EXPECT_LAZY_CLEAR(expectedLazyClearCount, queue.Submit(1, &commandBuffer));
                 }
 
                 wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
diff --git a/src/dawn/tests/end2end/CopyTests.cpp b/src/dawn/tests/end2end/CopyTests.cpp
index 64da8d2..baad726 100644
--- a/src/dawn/tests/end2end/CopyTests.cpp
+++ b/src/dawn/tests/end2end/CopyTests.cpp
@@ -4302,5 +4302,65 @@
                           // clang-format on
                       }));
 
+class BlitTextureToBufferTest : public DawnTest {};
+
+// Test that encoding a CopyTextureToBuffer but not submitting it doesn't mark the buffer as
+// initialized.
+TEST_P(BlitTextureToBufferTest, NoSubmitDoesNotMarkInitialized) {
+    DAWN_TEST_UNSUPPORTED_IF(UsesWire());
+
+    // Create a buffer that we will use as the destination of a CopyTextureToBuffer.
+    wgpu::BufferDescriptor bufferDesc;
+    bufferDesc.size = 256;
+    bufferDesc.usage = wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::CopyDst;
+    wgpu::Buffer buffer = device.CreateBuffer(&bufferDesc);
+
+    // Create a source texture.
+    wgpu::TextureDescriptor textureDesc;
+    textureDesc.size = {64, 1, 1};
+    textureDesc.format = wgpu::TextureFormat::R32Float;
+    textureDesc.usage = wgpu::TextureUsage::CopySrc;
+    wgpu::Texture texture = device.CreateTexture(&textureDesc);
+
+    wgpu::TexelCopyTextureInfo src = utils::CreateTexelCopyTextureInfo(texture, 0, {0, 0, 0});
+    wgpu::TexelCopyBufferInfo dst = utils::CreateTexelCopyBufferInfo(buffer, 0, 256, 1);
+    wgpu::Extent3D copySize = {64, 1, 1};
+
+    // Encode the CopyTextureToBuffer.
+    wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
+    encoder.CopyTextureToBuffer(&src, &dst, &copySize);
+    // Finish the encoder, but do NOT submit the command buffer.
+    encoder.Finish();
+
+    // Now, if we use the buffer in a way that requires initialization (e.g., as a source of a
+    // copy), it should be lazy-cleared because the previous CopyTextureToBuffer was never
+    // submitted.
+    wgpu::BufferDescriptor dstBufferDesc;
+    dstBufferDesc.size = 256;
+    dstBufferDesc.usage = wgpu::BufferUsage::CopyDst | wgpu::BufferUsage::CopySrc;
+    wgpu::Buffer dstBuffer = device.CreateBuffer(&dstBufferDesc);
+
+    wgpu::CommandEncoder encoder2 = device.CreateCommandEncoder();
+    encoder2.CopyBufferToBuffer(buffer, 0, dstBuffer, 0, 256);
+    wgpu::CommandBuffer cb = encoder2.Finish();
+
+    size_t lazyClearsBefore = native::GetLazyClearCountForTesting(device.Get());
+    queue.Submit(1, &cb);
+    size_t lazyClearsAfter = native::GetLazyClearCountForTesting(device.Get());
+
+    // If the buffer was incorrectly marked as initialized during encoding of the first command,
+    // lazyClearsAfter - lazyClearsBefore will be 0.
+    // Otherwise, it should be 1.
+    EXPECT_EQ(lazyClearsAfter - lazyClearsBefore, 1u);
+}
+
+DAWN_INSTANTIATE_TEST(BlitTextureToBufferTest,
+                      D3D11Backend({"use_blit_for_t2b"}),
+                      D3D12Backend({"use_blit_for_t2b"}),
+                      MetalBackend({"use_blit_for_t2b"}),
+                      OpenGLBackend({"use_blit_for_t2b"}),
+                      OpenGLESBackend({"use_blit_for_t2b"}),
+                      VulkanBackend({"use_blit_for_t2b"}));
+
 }  // anonymous namespace
 }  // namespace dawn
diff --git a/src/dawn/tests/end2end/TextureZeroInitTests.cpp b/src/dawn/tests/end2end/TextureZeroInitTests.cpp
index 7f6f0d7..97a5481 100644
--- a/src/dawn/tests/end2end/TextureZeroInitTests.cpp
+++ b/src/dawn/tests/end2end/TextureZeroInitTests.cpp
@@ -311,7 +311,14 @@
     wgpu::CommandBuffer commandBuffer = encoder.Finish();
 
     // Expect texture to be lazy initialized.
-    EXPECT_LAZY_CLEAR(1u, queue.Submit(1, &commandBuffer));
+    // TODO(b/513631768): SetInitialized is now skipped for use_blit_for_t2b path.
+    // If blit is used for T2B, the destination buffer is NOT marked as initialized during encoding,
+    // so it will also be lazy cleared during the first usage (which is the blit itself).
+    uint32_t expectedLazyClearCount = 1u;
+    if (HasToggleEnabled("use_blit_for_t2b")) {
+        expectedLazyClearCount++;
+    }
+    EXPECT_LAZY_CLEAR(expectedLazyClearCount, queue.Submit(1, &commandBuffer));
 
     // Expect texture subresource initialized to be true
     EXPECT_TRUE(native::IsTextureSubresourceInitialized(texture.Get(), 0, 1, 0, kArrayLayers));

diff --git a/src/dawn/tests/end2end/BufferZeroInitTests.cpp b/src/dawn/tests/end2end/BufferZeroInitTests.cpp
index 6d86a10..625446a 100644
--- a/src/dawn/tests/end2end/BufferZeroInitTests.cpp
+++ b/src/dawn/tests/end2end/BufferZeroInitTests.cpp
@@ -145,7 +145,14 @@
         wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
         encoder.CopyTextureToBuffer(&texelCopyTextureInfo, &texelCopyBufferInfo, &spec.textureSize);
         wgpu::CommandBuffer commandBuffer = encoder.Finish();
-        EXPECT_LAZY_CLEAR(spec.lazyClearCount, queue.Submit(1, &commandBuffer));
+
+        // TODO(b/513631768): SetInitialized is now skipped for use_blit_for_t2b path.
+        uint32_t expectedLazyClearCount = spec.lazyClearCount;
+        if (expectedLazyClearCount == 0u && (HasToggleEnabled("use_blit_for_t2b"))) {
+            expectedLazyClearCount = 1u;
+        }
+
+        EXPECT_LAZY_CLEAR(expectedLazyClearCount, queue.Submit(1, &commandBuffer));
 
         const uint64_t expectedValueCount = bufferSize / sizeof(float);
         std::vector<float> expectedValues(expectedValueCount, 0.f);
@@ -1153,6 +1160,10 @@
     // TODO(crbug.com/473593119): [Capture] size not multiple of 4.
     DAWN_SUPPRESS_TEST_IF(IsCaptureReplayCheckingEnabled());
 
+    // TODO(crbug.com/513631768): Skip D3D11 as they may use intermediate buffer for blit
+    // path and fail for EXPECT_LAZY_CLEAR.
+    DAWN_SUPPRESS_TEST_IF(IsD3D11());
+
     constexpr wgpu::TextureFormat kColorAttachmentFormat = wgpu::TextureFormat::RGBA8Unorm;
     // A small sub-4-byte format means a single vertex can fit entirely within the padded buffer,
     // touching some of the padding. Test a small format, as well as larger formats.
@@ -1222,7 +1233,13 @@
                     encoder.CopyTextureToBuffer(&zeroTextureSrc, &dst, &extent);
 
                     wgpu::CommandBuffer commandBuffer = encoder.Finish();
-                    EXPECT_LAZY_CLEAR(0u, queue.Submit(1, &commandBuffer));
+
+                    // TODO(b/513631768): SetInitialized is now skipped for use_blit_for_t2b path.
+                    uint32_t expectedLazyClearCount = 0u;
+                    if (HasToggleEnabled("use_blit_for_t2b")) {
+                        expectedLazyClearCount = 1u;
+                    }
+                    EXPECT_LAZY_CLEAR(expectedLazyClearCount, queue.Submit(1, &commandBuffer));
                 }
 
                 wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
diff --git a/src/dawn/tests/end2end/CopyTests.cpp b/src/dawn/tests/end2end/CopyTests.cpp
index 64da8d2..baad726 100644
--- a/src/dawn/tests/end2end/CopyTests.cpp
+++ b/src/dawn/tests/end2end/CopyTests.cpp
@@ -4302,5 +4302,65 @@
                           // clang-format on
                       }));
 
+class BlitTextureToBufferTest : public DawnTest {};
+
+// Test that encoding a CopyTextureToBuffer but not submitting it doesn't mark the buffer as
+// initialized.
+TEST_P(BlitTextureToBufferTest, NoSubmitDoesNotMarkInitialized) {
+    DAWN_TEST_UNSUPPORTED_IF(UsesWire());
+
+    // Create a buffer that we will use as the destination of a CopyTextureToBuffer.
+    wgpu::BufferDescriptor bufferDesc;
+    bufferDesc.size = 256;
+    bufferDesc.usage = wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::CopyDst;
+    wgpu::Buffer buffer = device.CreateBuffer(&bufferDesc);
+
+    // Create a source texture.
+    wgpu::TextureDescriptor textureDesc;
+    textureDesc.size = {64, 1, 1};
+    textureDesc.format = wgpu::TextureFormat::R32Float;
+    textureDesc.usage = wgpu::TextureUsage::CopySrc;
+    wgpu::Texture texture = device.CreateTexture(&textureDesc);
+
+    wgpu::TexelCopyTextureInfo src = utils::CreateTexelCopyTextureInfo(texture, 0, {0, 0, 0});
+    wgpu::TexelCopyBufferInfo dst = utils::CreateTexelCopyBufferInfo(buffer, 0, 256, 1);
+    wgpu::Extent3D copySize = {64, 1, 1};
+
+    // Encode the CopyTextureToBuffer.
+    wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
+    encoder.CopyTextureToBuffer(&src, &dst, &copySize);
+    // Finish the encoder, but do NOT submit the command buffer.
+    encoder.Finish();
+
+    // Now, if we use the buffer in a way that requires initialization (e.g., as a source of a
+    // copy), it should be lazy-cleared because the previous CopyTextureToBuffer was never
+    // submitted.
+    wgpu::BufferDescriptor dstBufferDesc;
+    dstBufferDesc.size = 256;
+    dstBufferDesc.usage = wgpu::BufferUsage::CopyDst | wgpu::BufferUsage::CopySrc;
+    wgpu::Buffer dstBuffer = device.CreateBuffer(&dstBufferDesc);
+
+    wgpu::CommandEncoder encoder2 = device.CreateCommandEncoder();
+    encoder2.CopyBufferToBuffer(buffer, 0, dstBuffer, 0, 256);
+    wgpu::CommandBuffer cb = encoder2.Finish();
+
+    size_t lazyClearsBefore = native::GetLazyClearCountForTesting(device.Get());
+    queue.Submit(1, &cb);
+    size_t lazyClearsAfter = native::GetLazyClearCountForTesting(device.Get());
+
+    // If the buffer was incorrectly marked as initialized during encoding of the first command,
+    // lazyClearsAfter - lazyClearsBefore will be 0.
+    // Otherwise, it should be 1.
+    EXPECT_EQ(lazyClearsAfter - lazyClearsBefore, 1u);
+}
+
+DAWN_INSTANTIATE_TEST(BlitTextureToBufferTest,
+                      D3D11Backend({"use_blit_for_t2b"}),
+                      D3D12Backend({"use_blit_for_t2b"}),
+                      MetalBackend({"use_blit_for_t2b"}),
+                      OpenGLBackend({"use_blit_for_t2b"}),
+                      OpenGLESBackend({"use_blit_for_t2b"}),
+                      VulkanBackend({"use_blit_for_t2b"}));
+
 }  // anonymous namespace
 }  // namespace dawn
diff --git a/src/dawn/tests/end2end/TextureZeroInitTests.cpp b/src/dawn/tests/end2end/TextureZeroInitTests.cpp
index 7f6f0d7..97a5481 100644
--- a/src/dawn/tests/end2end/TextureZeroInitTests.cpp
+++ b/src/dawn/tests/end2end/TextureZeroInitTests.cpp
@@ -311,7 +311,14 @@
     wgpu::CommandBuffer commandBuffer = encoder.Finish();
 
     // Expect texture to be lazy initialized.
-    EXPECT_LAZY_CLEAR(1u, queue.Submit(1, &commandBuffer));
+    // TODO(b/513631768): SetInitialized is now skipped for use_blit_for_t2b path.
+    // If blit is used for T2B, the destination buffer is NOT marked as initialized during encoding,
+    // so it will also be lazy cleared during the first usage (which is the blit itself).
+    uint32_t expectedLazyClearCount = 1u;
+    if (HasToggleEnabled("use_blit_for_t2b")) {
+        expectedLazyClearCount++;
+    }
+    EXPECT_LAZY_CLEAR(expectedLazyClearCount, queue.Submit(1, &commandBuffer));
 
     // Expect texture subresource initialized to be true
     EXPECT_TRUE(native::IsTextureSubresourceInitialized(texture.Get(), 0, 1, 0, kArrayLayers));