tree 779f9a7bec7205fbf877dcc03d19b01193e1c52f
parent abec145b0403af013e5176b0d8b2972d03d00fa4
author David 'Digit' Turner <digit@google.com> 1568026328 +0000
committer Commit Bot service account <commit-bot@chromium.org> 1568026328 +0000

Enable Vulkan for Chromium Fuchsia build.

Enable the Vulkan backend when building Dawn with
the Chromium build system for Fuchsia. To make this
work properly the following is required:

- Modify VulkanInfo.cpp and BackendVk.cpp to correctly probe
  the Fuchsia swapchain layer and its layer extension, as well
  as enabling them when creating a new VkInstance.

- Modify VulkanFunctions.cpp to load the Fuchsia swapchain
  related extension for this platform only.

- Provide a small mock GLFW library for Fuchsia under
  src/utils/Glfw3Fuchsia.cpp, since the upstream project
  does not support this platform at all. Its purpose is
  only to allow the creation of the right VulkanBinding
  instance, which depends on the creation of a display
  surface for latter swapchain creation.

- Add //third_party/fuchsia-sdk:vulkan_base and
  //third_party/fuchsia-sdk:vulkan_validation as
  data_deps of the libdawn_native_sources target in
  order to ensure that the Fuchsia package created by
  the build system will include the correct Vulkan
  libraries (loader and validation layers).

This builds correctly, and both dawn_unittests and
dawn_end2end_tests will run on a real Fuchsia device
or inside the Fuchsia emulator, using either GPU
virtualization or a software-based renderer.

Note: dawn_unittests will also run inside QEMU, but
not dawn_end2end_tests, since the latter requires
proper GPU emulation which is not available in this
environment.

NOTE: All end2end tests pass using a device with
      an "Intel HD Graphics 615 (Kaby Lake GT2)"
      adapter. However:

       - For some reason, a single test takes up
         to 129 seconds to pass
	 (BufferSetSubDataTests.ManySetSubData/Vulkan).

       - The test process crashes inside VkDestroyInstance(),
         apparently inside the Fuchsia-specific imagepipe
	 layer (which implements swapchain support).
	 This is likely a bug in the layer itself, and
	 not Dawn.

    Also, may end2end tests will crash when run inside
    the Fuchsia emulator (which uses GPU virtualization
    to talk to the host GPU). The crashes happen inside
    libvulkan-goldfish.so, the emulator-specific Vulkan
    ICD on this sytem. Not a Dawn bug either.

Bug=dawn:221
Change-Id: Id3598b673e8c6393f24db728b8da49fdde3cac76
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/8963
Commit-Queue: David Turner <digit@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>