Vulkan: fix undefined right shift in GetMask

Bug: chromium:1137170
Change-Id: I95efdc7888e44f2b4227f9c0d892b9102cead0bb
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2469616
Reviewed-by: Jamie Madill <[email protected]>
Reviewed-by: Shahbaz Youssefi <[email protected]>
Commit-Queue: Jamie Madill <[email protected]>

Author: lexaknyazev

src/libANGLE/angletypes.h

@@ -432,6 +432,7 @@ class BlendStateExt final
 
         static constexpr Type GetMask(const size_t drawBuffers)
         {
+            ASSERT(drawBuffers > 0);
             ASSERT(drawBuffers <= IMPLEMENTATION_MAX_DRAW_BUFFERS);
             return static_cast<Type>(0xFFFFFFFFFFFFFFFFull >> (64 - drawBuffers * kBits));
         }

src/libANGLE/renderer/vulkan/ContextVk.cpp

@@ -123,10 +123,6 @@ constexpr gl::ShaderMap<vk::ImageLayout> kShaderWriteImageLayouts = {
     {gl::ShaderType::Geometry, vk::ImageLayout::GeometryShaderWrite},
     {gl::ShaderType::Compute, vk::ImageLayout::ComputeShaderWrite}};
 
-constexpr VkColorComponentFlags kAllColorChannelsMask =
-    (VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT |
-     VK_COLOR_COMPONENT_A_BIT);
-
 constexpr VkBufferUsageFlags kVertexBufferUsage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
 constexpr size_t kDefaultValueSize              = sizeof(gl::VertexAttribCurrentValueData::Values);
 constexpr size_t kDefaultBufferSize             = kDefaultValueSize * 16;
@@ -648,6 +644,7 @@ ContextVk::ContextVk(const gl::State &state, gl::ErrorSet *errorSet, RendererVk
       mCurrentDrawElementsType(gl::DrawElementsType::InvalidEnum),
       mXfbBaseVertex(0),
       mXfbVertexCountPerInstance(0),
+      mClearColorMasks(0),
       mFlipYForCurrentSurface(false),
       mIsAnyHostVisibleBufferWritten(false),
       mEmulateSeamfulCubeMapSampling(false),
@@ -669,10 +666,6 @@ ContextVk::ContextVk(const gl::State &state, gl::ErrorSet *errorSet, RendererVk
     memset(&mClearColorValue, 0, sizeof(mClearColorValue));
     memset(&mClearDepthStencilValue, 0, sizeof(mClearDepthStencilValue));
 
-    mClearColorMasks = gl::BlendStateExt::ColorMaskStorage::GetReplicatedValue(
-        kAllColorChannelsMask,
-        gl::BlendStateExt::ColorMaskStorage::GetMask(getCaps().maxDrawBuffers));
-
     mNonIndexedDirtyBitsMask.set();
     mNonIndexedDirtyBitsMask.reset(DIRTY_BIT_INDEX_BUFFER);