Fix a bug with D3D12 buffer alignment computation
We should use D3D12_CONSTANT_BUFFER_DATA_PLACEMENT_ALIGNMENT
if the usage *contains* Uniform usage, not if it is exactly
equal.
Fixed: dawn:1085
Change-Id: I540081e550c9e88efeb08169cecdc40b68d36d14
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/62242
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/dawn_native/DawnNative.cpp b/src/dawn_native/DawnNative.cpp
index 15fd697..b5e1ba40 100644
--- a/src/dawn_native/DawnNative.cpp
+++ b/src/dawn_native/DawnNative.cpp
@@ -13,6 +13,8 @@
// limitations under the License.
#include "dawn_native/DawnNative.h"
+
+#include "dawn_native/Buffer.h"
#include "dawn_native/Device.h"
#include "dawn_native/Instance.h"
#include "dawn_native/Texture.h"
@@ -230,4 +232,8 @@
return object->GetLabel().c_str();
}
+ uint64_t GetAllocatedSizeForTesting(WGPUBuffer buffer) {
+ return reinterpret_cast<const BufferBase*>(buffer)->GetAllocatedSize();
+ }
+
} // namespace dawn_native
diff --git a/src/dawn_native/d3d12/BindGroupD3D12.cpp b/src/dawn_native/d3d12/BindGroupD3D12.cpp
index 4832cdd..47c501a 100644
--- a/src/dawn_native/d3d12/BindGroupD3D12.cpp
+++ b/src/dawn_native/d3d12/BindGroupD3D12.cpp
@@ -69,7 +69,8 @@
switch (bindingInfo.buffer.type) {
case wgpu::BufferBindingType::Uniform: {
D3D12_CONSTANT_BUFFER_VIEW_DESC desc;
- desc.SizeInBytes = Align(binding.size, 256);
+ desc.SizeInBytes =
+ Align(binding.size, D3D12_CONSTANT_BUFFER_DATA_PLACEMENT_ALIGNMENT);
desc.BufferLocation =
ToBackend(binding.buffer)->GetVA() + binding.offset;
diff --git a/src/dawn_native/d3d12/BufferD3D12.cpp b/src/dawn_native/d3d12/BufferD3D12.cpp
index 67ebc47..39fcb83 100644
--- a/src/dawn_native/d3d12/BufferD3D12.cpp
+++ b/src/dawn_native/d3d12/BufferD3D12.cpp
@@ -82,12 +82,16 @@
}
size_t D3D12BufferSizeAlignment(wgpu::BufferUsage usage) {
- switch (usage) {
- case wgpu::BufferUsage::Uniform:
- return D3D12_CONSTANT_BUFFER_DATA_PLACEMENT_ALIGNMENT;
- default:
- return 1;
+ if ((usage & wgpu::BufferUsage::Uniform) != 0) {
+ // D3D buffers are always resource size aligned to 64KB. However, D3D12's validation
+ // forbids binding a CBV to an unaligned size. To prevent, one can always safely
+ // align the buffer size to the CBV data alignment as other buffer usages
+ // ignore it (no size check). The validation will still enforce bound checks with
+ // the unaligned size returned by GetSize().
+ // https://docs.microsoft.com/en-us/windows/win32/direct3d12/uploading-resources#buffer-alignment
+ return D3D12_CONSTANT_BUFFER_DATA_PLACEMENT_ALIGNMENT;
}
+ return 1;
}
} // namespace
@@ -103,12 +107,6 @@
}
MaybeError Buffer::Initialize(bool mappedAtCreation) {
- // D3D buffers are always resource size aligned to 64KB. However, D3D12's validation forbids
- // binding a CBV to an unaligned size. To prevent, one can always safely align the buffer
- // desc size to the CBV data alignment as other buffer usages ignore it (no size check).
- // The validation will still enforce bound checks with the unaligned size returned by
- // GetSize().
- // https://docs.microsoft.com/en-us/windows/win32/direct3d12/uploading-resources#buffer-alignment
// Allocate at least 4 bytes so clamped accesses are always in bounds.
uint64_t size = std::max(GetSize(), uint64_t(4u));
size_t alignment = D3D12BufferSizeAlignment(GetUsage());
diff --git a/src/include/dawn_native/DawnNative.h b/src/include/dawn_native/DawnNative.h
index a0a6229..4281e05 100644
--- a/src/include/dawn_native/DawnNative.h
+++ b/src/include/dawn_native/DawnNative.h
@@ -250,6 +250,8 @@
DAWN_NATIVE_EXPORT const char* GetObjectLabelForTesting(void* objectHandle);
+ DAWN_NATIVE_EXPORT uint64_t GetAllocatedSizeForTesting(WGPUBuffer buffer);
+
} // namespace dawn_native
#endif // DAWNNATIVE_DAWNNATIVE_H_
diff --git a/src/tests/BUILD.gn b/src/tests/BUILD.gn
index 8aa80f8..0c5964c 100644
--- a/src/tests/BUILD.gn
+++ b/src/tests/BUILD.gn
@@ -439,6 +439,7 @@
}
sources += [
+ "white_box/BufferAllocatedSizeTests.cpp",
"white_box/InternalResourceUsageTests.cpp",
"white_box/InternalStorageBufferBindingTests.cpp",
"white_box/QueryInternalShaderTests.cpp",
diff --git a/src/tests/white_box/BufferAllocatedSizeTests.cpp b/src/tests/white_box/BufferAllocatedSizeTests.cpp
new file mode 100644
index 0000000..15c1437
--- /dev/null
+++ b/src/tests/white_box/BufferAllocatedSizeTests.cpp
@@ -0,0 +1,85 @@
+// Copyright 2021 The Dawn Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "tests/DawnTest.h"
+
+#include "common/Math.h"
+#include "dawn_native/DawnNative.h"
+
+#include <algorithm>
+
+class BufferAllocatedSizeTests : public DawnTest {
+ protected:
+ wgpu::Buffer CreateBuffer(wgpu::BufferUsage usage, uint64_t size) {
+ wgpu::BufferDescriptor desc = {};
+ desc.usage = usage;
+ desc.size = size;
+ return device.CreateBuffer(&desc);
+ }
+
+ void SetUp() override {
+ DawnTest::SetUp();
+ DAWN_TEST_UNSUPPORTED_IF(UsesWire());
+ }
+};
+
+// Test expected allocated size for buffers with uniform usage
+TEST_P(BufferAllocatedSizeTests, UniformUsage) {
+ // Some backends have a minimum buffer size, so make sure
+ // we allocate above that.
+ constexpr uint32_t kMinBufferSize = 4u;
+
+ uint32_t requiredBufferAlignment = 1u;
+ if (IsD3D12()) {
+ requiredBufferAlignment = 256u;
+ } else if (IsMetal()) {
+ requiredBufferAlignment = 16u;
+ } else if (IsVulkan()) {
+ requiredBufferAlignment = 4u;
+ }
+
+ // Test uniform usage
+ {
+ const uint32_t bufferSize = kMinBufferSize;
+ wgpu::Buffer buffer = CreateBuffer(wgpu::BufferUsage::Uniform, bufferSize);
+ EXPECT_EQ(dawn_native::GetAllocatedSizeForTesting(buffer.Get()),
+ Align(bufferSize, requiredBufferAlignment));
+ }
+
+ // Test uniform usage and with size just above requiredBufferAlignment allocates to the next
+ // multiple of |requiredBufferAlignment|
+ {
+ const uint32_t bufferSize = std::max(1u + requiredBufferAlignment, kMinBufferSize);
+ wgpu::Buffer buffer =
+ CreateBuffer(wgpu::BufferUsage::Uniform | wgpu::BufferUsage::Storage, bufferSize);
+ EXPECT_EQ(dawn_native::GetAllocatedSizeForTesting(buffer.Get()),
+ Align(bufferSize, requiredBufferAlignment));
+ }
+
+ // Test uniform usage and another usage
+ {
+ const uint32_t bufferSize = kMinBufferSize;
+ wgpu::Buffer buffer =
+ CreateBuffer(wgpu::BufferUsage::Uniform | wgpu::BufferUsage::Storage, bufferSize);
+ EXPECT_EQ(dawn_native::GetAllocatedSizeForTesting(buffer.Get()),
+ Align(bufferSize, requiredBufferAlignment));
+ }
+}
+
+DAWN_INSTANTIATE_TEST(BufferAllocatedSizeTests,
+ D3D12Backend(),
+ MetalBackend(),
+ OpenGLBackend(),
+ OpenGLESBackend(),
+ VulkanBackend());
