Introduce WriteBuffer command

This command copies data from host memory into a GPU buffer. It's
analogous to Queue::WriteBuffer, but executed in the context of a
command buffer, sequenced with other encoded commands. This is useful
for supporting a notion of a shared scratch buffer, with a single
allocation whose contents may need to be overwritten with new data
before each pass that uses it.

Bug: dawn:809
Change-Id: If58d49c52a41127e2980dd626fd687eb1c91fe28
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/64001
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>

src/tests/unittests/validation/WriteBufferTests.cpp

@@ -0,0 +1,104 @@
+// 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/unittests/validation/ValidationTest.h"
+
+#include "utils/ComboRenderPipelineDescriptor.h"
+#include "utils/WGPUHelpers.h"
+
+namespace {
+
+    class WriteBufferTest : public ValidationTest {
+      public:
+        wgpu::Buffer CreateWritableBuffer(uint64_t size) {
+            wgpu::BufferDescriptor desc;
+            desc.usage = wgpu::BufferUsage::CopyDst;
+            desc.size = size;
+            return device.CreateBuffer(&desc);
+        }
+
+        wgpu::CommandBuffer EncodeWriteBuffer(wgpu::Buffer buffer,
+                                              uint64_t bufferOffset,
+                                              uint64_t size) {
+            std::vector<uint8_t> data(size);
+            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
+            encoder.WriteBuffer(buffer, bufferOffset, data.data(), size);
+            return encoder.Finish();
+        }
+    };
+
+    // Tests that the buffer offset is validated to be a multiple of 4 bytes.
+    TEST_F(WriteBufferTest, OffsetAlignment) {
+        wgpu::Buffer buffer = CreateWritableBuffer(64);
+        EncodeWriteBuffer(buffer, 0, 4);
+        EncodeWriteBuffer(buffer, 4, 4);
+        EncodeWriteBuffer(buffer, 60, 4);
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 1, 4));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 2, 4));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 3, 4));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 5, 4));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 11, 4));
+    }
+
+    // Tests that the buffer size is validated to be a multiple of 4 bytes.
+    TEST_F(WriteBufferTest, SizeAlignment) {
+        wgpu::Buffer buffer = CreateWritableBuffer(64);
+        EncodeWriteBuffer(buffer, 0, 64);
+        EncodeWriteBuffer(buffer, 4, 60);
+        EncodeWriteBuffer(buffer, 40, 24);
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 0, 63));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 4, 1));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 4, 2));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 40, 23));
+    }
+
+    // Tests that the buffer size and offset are validated to fit within the bounds of the buffer.
+    TEST_F(WriteBufferTest, BufferBounds) {
+        wgpu::Buffer buffer = CreateWritableBuffer(64);
+        EncodeWriteBuffer(buffer, 0, 64);
+        EncodeWriteBuffer(buffer, 4, 60);
+        EncodeWriteBuffer(buffer, 40, 24);
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 0, 68));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 4, 64));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 60, 8));
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 64, 4));
+    }
+
+    // Tests that the destination buffer's usage is validated to contain CopyDst.
+    TEST_F(WriteBufferTest, RequireCopyDstUsage) {
+        wgpu::BufferDescriptor desc;
+        desc.usage = wgpu::BufferUsage::CopySrc;
+        desc.size = 64;
+        wgpu::Buffer buffer = device.CreateBuffer(&desc);
+
+        ASSERT_DEVICE_ERROR(EncodeWriteBuffer(buffer, 0, 64));
+    }
+
+    // Tests that the destination buffer's state is validated at submission.
+    TEST_F(WriteBufferTest, ValidBufferState) {
+        wgpu::BufferDescriptor desc;
+        desc.usage = wgpu::BufferUsage::CopyDst;
+        desc.size = 64;
+        desc.mappedAtCreation = true;
+        wgpu::Buffer buffer = device.CreateBuffer(&desc);
+
+        wgpu::CommandBuffer commands = EncodeWriteBuffer(buffer, 0, 64);
+        ASSERT_DEVICE_ERROR(device.GetQueue().Submit(1, &commands));
+
+        commands = EncodeWriteBuffer(buffer, 0, 64);
+        buffer.Unmap();
+        device.GetQueue().Submit(1, &commands);
+    }
+
+}  // namespace