Vulkan: Add DS ReadOnly mode to Framebuffer/RP caches.

src/libANGLE/renderer/vulkan/FramebufferVk.cpp

@@ -1695,7 +1695,8 @@ void FramebufferVk::updateRenderPassDesc()
     if (depthStencilRenderTarget)
     {
         mRenderPassDesc.packDepthStencilAttachment(
-            depthStencilRenderTarget->getImageForRenderPass().getFormat().intendedFormatID);
+            depthStencilRenderTarget->getImageForRenderPass().getFormat().intendedFormatID,
+            vk::ResourceAccess::Write);
     }
 }
 

src/libANGLE/renderer/vulkan/vk_cache_utils.cpp

@@ -291,6 +291,7 @@ angle::Result InitializeRenderPassFromDesc(vk::Context *context,
     // Pack depth/stencil attachment, if any
     if (desc.hasDepthStencilAttachment())
     {
+        ResourceAccess dsAccess      = desc.getDepthStencilAccess();
         uint32_t depthStencilIndex   = static_cast<uint32_t>(desc.depthStencilAttachmentIndex());
         uint32_t depthStencilIndexVk = colorAttachmentCount;
 
@@ -299,7 +300,18 @@ angle::Result InitializeRenderPassFromDesc(vk::Context *context,
         const vk::Format &format = context->getRenderer()->getFormat(formatID);
 
         depthStencilAttachmentRef.attachment = depthStencilIndexVk;
-        depthStencilAttachmentRef.layout     = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
+
+        switch (dsAccess)
+        {
+            case ResourceAccess::ReadOnly:
+                depthStencilAttachmentRef.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL;
+                break;
+            case ResourceAccess::Write:
+                depthStencilAttachmentRef.layout = VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL;
+                break;
+            default:
+                UNREACHABLE();
+        }
 
         UnpackAttachmentDesc(&attachmentDescs[depthStencilIndexVk], format, desc.samples(),
                              ops[depthStencilIndexVk]);
@@ -466,13 +478,44 @@ void RenderPassDesc::setSamples(GLint samples)
     SetBitField(mLogSamples, PackSampleCount(samples));
 }
 
+// We can use a bit packing trick to combine two states into a smaller number of bits. The first
+// state is the "depth stencil access" mode which can be Unused/ReadOnly/Write. Naively the DS
+// access would take 2 bits. The color attachment count state can have 9 values: no attachments +
+// 1-8 attachments. Naively this would take 4 bits. So our total bit count naively would be 6. We
+// can pack into 5 bits simply by treating the combination of the 9*3 values as an enum with 27
+// values. 5 bits gives us 32 possible values. Mod and divide allow us to access the two different
+// state components of the enum.
+enum PackedAttachmentCount : uint8_t
+{
+    NoColor                   = 0,
+    ColorMax                  = NoColor + gl::IMPLEMENTATION_MAX_DRAW_BUFFERS,
+    NoColorDepthStencilRead   = ColorMax + 1,
+    ColorMaxDepthStencilRead  = NoColorDepthStencilRead + gl::IMPLEMENTATION_MAX_DRAW_BUFFERS,
+    NoColorDepthStencilWrite  = ColorMaxDepthStencilRead + 1,
+    ColorMaxDepthStencilWrite = NoColorDepthStencilWrite + gl::IMPLEMENTATION_MAX_DRAW_BUFFERS,
+    EnumCount,
+};
+
+static_assert(PackedAttachmentCount::EnumCount < angle::Bit<uint8_t>(5), "Bit overflow");
+
+size_t RenderPassDesc::colorAttachmentRange() const
+{
+    return mPackedColorAttachmentRangeAndDSAccess % (PackedAttachmentCount::ColorMax + 1);
+}
+
+ResourceAccess RenderPassDesc::getDepthStencilAccess() const
+{
+    return static_cast<ResourceAccess>(mPackedColorAttachmentRangeAndDSAccess /
+                                       (PackedAttachmentCount::ColorMax + 1));
+}
+
 void RenderPassDesc::packColorAttachment(size_t colorIndexGL, angle::FormatID formatID)
 {
     ASSERT(colorIndexGL < mAttachmentFormats.size());
     static_assert(angle::kNumANGLEFormats < std::numeric_limits<uint8_t>::max(),
                   "Too many ANGLE formats to fit in uint8_t");
     // Force the user to pack the depth/stencil attachment last.
-    ASSERT(mHasDepthStencilAttachment == false);
+    ASSERT(!hasDepthStencilAttachment());
     // This function should only be called for enabled GL color attachments.
     ASSERT(formatID != angle::FormatID::NONE);
 
@@ -481,7 +524,8 @@ void RenderPassDesc::packColorAttachment(size_t colorIndexGL, angle::FormatID fo
 
     // Set color attachment range such that it covers the range from index 0 through last
     // active index.  This is the reason why we need depth/stencil to be packed last.
-    SetBitField(mColorAttachmentRange, std::max<size_t>(mColorAttachmentRange, colorIndexGL + 1));
+    SetBitField(mPackedColorAttachmentRangeAndDSAccess,
+                std::max<size_t>(mPackedColorAttachmentRangeAndDSAccess, colorIndexGL + 1));
 }
 
 void RenderPassDesc::packColorAttachmentGap(size_t colorIndexGL)
@@ -490,17 +534,17 @@ void RenderPassDesc::packColorAttachmentGap(size_t colorIndexGL)
     static_assert(angle::kNumANGLEFormats < std::numeric_limits<uint8_t>::max(),
                   "Too many ANGLE formats to fit in uint8_t");
     // Force the user to pack the depth/stencil attachment last.
-    ASSERT(mHasDepthStencilAttachment == false);
+    ASSERT(!hasDepthStencilAttachment());
 
     // Use NONE as a flag for gaps in GL color attachments.
     uint8_t &packedFormat = mAttachmentFormats[colorIndexGL];
     SetBitField(packedFormat, angle::FormatID::NONE);
 }
 
-void RenderPassDesc::packDepthStencilAttachment(angle::FormatID formatID)
+void RenderPassDesc::packDepthStencilAttachment(angle::FormatID formatID, ResourceAccess access)
 {
-    // Though written as Count, there is only ever a single depth/stencil attachment.
-    ASSERT(mHasDepthStencilAttachment == false);
+    ASSERT(access != ResourceAccess::Unused);
+    ASSERT(!hasDepthStencilAttachment());
 
     size_t index = depthStencilAttachmentIndex();
     ASSERT(index < mAttachmentFormats.size());
@@ -508,7 +552,10 @@ void RenderPassDesc::packDepthStencilAttachment(angle::FormatID formatID)
     uint8_t &packedFormat = mAttachmentFormats[index];
     SetBitField(packedFormat, formatID);
 
-    mHasDepthStencilAttachment = true;
+    size_t colorRange = colorAttachmentRange();
+    size_t offset =
+        access == ResourceAccess::ReadOnly ? NoColorDepthStencilRead : NoColorDepthStencilWrite;
+    SetBitField(mPackedColorAttachmentRangeAndDSAccess, colorRange + offset);
 }
 
 void RenderPassDesc::packColorResolveAttachment(size_t colorIndexGL)
@@ -538,14 +585,16 @@ bool RenderPassDesc::isColorAttachmentEnabled(size_t colorIndexGL) const
 size_t RenderPassDesc::attachmentCount() const
 {
     size_t colorAttachmentCount = 0;
-    for (size_t i = 0; i < mColorAttachmentRange; ++i)
+    size_t colorRange           = colorAttachmentRange();
+    for (size_t i = 0; i < colorRange; ++i)
     {
         colorAttachmentCount += isColorAttachmentEnabled(i);
     }
 
     // Note that there are no gaps in depth/stencil attachments.  In fact there is a maximum of 1 of
     // it.
-    return colorAttachmentCount + mColorResolveAttachmentMask.count() + mHasDepthStencilAttachment;
+    size_t depthStencilCount = hasDepthStencilAttachment() ? 1 : 0;
+    return colorAttachmentCount + mColorResolveAttachmentMask.count() + depthStencilCount;
 }
 
 bool operator==(const RenderPassDesc &lhs, const RenderPassDesc &rhs)
@@ -1812,7 +1861,7 @@ void FramebufferDesc::update(uint32_t index, ImageViewSubresourceSerial serial)
     mSerials[index] = serial;
     if (serial.imageViewSerial.valid())
     {
-        mMaxIndex = std::max(mMaxIndex, index + 1);
+        mMaxIndex = std::max(mMaxIndex, static_cast<uint16_t>(index + 1));
     }
 }
 
@@ -1831,6 +1880,11 @@ void FramebufferDesc::updateDepthStencil(ImageViewSubresourceSerial serial)
     update(kFramebufferDescDepthStencilIndex, serial);
 }
 
+void FramebufferDesc::updateReadOnlyDepth(bool readOnlyDepth)
+{
+    mReadOnlyDepth = readOnlyDepth;
+}
+
 size_t FramebufferDesc::hash() const
 {
     return angle::ComputeGenericHash(&mSerials, sizeof(mSerials[0]) * (mMaxIndex + 1));
@@ -1838,7 +1892,8 @@ size_t FramebufferDesc::hash() const
 
 void FramebufferDesc::reset()
 {
-    mMaxIndex = 0;
+    mMaxIndex      = 0;
+    mReadOnlyDepth = false;
     memset(&mSerials, 0, sizeof(mSerials));
 }
 
@@ -1849,6 +1904,11 @@ bool FramebufferDesc::operator==(const FramebufferDesc &other) const
         return false;
     }
 
+    if (mReadOnlyDepth != other.mReadOnlyDepth)
+    {
+        return false;
+    }
+
     size_t validRegionSize = sizeof(mSerials[0]) * mMaxIndex;
     return memcmp(&mSerials, &other.mSerials, validRegionSize) == 0;
 }
@@ -2090,9 +2150,20 @@ angle::Result RenderPassCache::addRenderPass(ContextVk *contextVk,
 
     if (desc.hasDepthStencilAttachment())
     {
+        vk::ResourceAccess dsAccess = desc.getDepthStencilAccess();
+        vk::ImageLayout imageLayout;
+        if (dsAccess == vk::ResourceAccess::ReadOnly)
+        {
+            imageLayout = vk::ImageLayout::DepthStencilReadOnly;
+        }
+        else
+        {
+            ASSERT(dsAccess == vk::ResourceAccess::Write);
+            imageLayout = vk::ImageLayout::DepthStencilAttachment;
+        }
+
         uint32_t depthStencilIndexVk = colorAttachmentCount;
-        ops.initWithLoadStore(depthStencilIndexVk, vk::ImageLayout::DepthStencilAttachment,
-                              vk::ImageLayout::DepthStencilAttachment);
+        ops.initWithLoadStore(depthStencilIndexVk, imageLayout, imageLayout);
     }
 
     return getRenderPassWithOps(contextVk, serial, desc, ops, renderPassOut);

src/libANGLE/renderer/vulkan/vk_cache_utils.h

@@ -59,6 +59,13 @@ using RefCountedSamplerYcbcrConversion = RefCounted<SamplerYcbcrConversion>;
 // Enable struct padding warnings for the code below since it is used in caches.
 ANGLE_ENABLE_STRUCT_PADDING_WARNINGS
 
+enum ResourceAccess
+{
+    Unused,
+    ReadOnly,
+    Write,
+};
+
 class alignas(4) RenderPassDesc final
 {
   public:
@@ -73,18 +80,22 @@ class alignas(4) RenderPassDesc final
     void packColorAttachmentGap(size_t colorIndexGL);
     // The caller must pack the depth/stencil attachment last, which is packed right after the color
     // attachments (including gaps), i.e. with an index starting from |colorAttachmentRange()|.
-    void packDepthStencilAttachment(angle::FormatID angleFormatID);
+    void packDepthStencilAttachment(angle::FormatID angleFormatID, ResourceAccess access);
     // Indicate that a color attachment should have a corresponding resolve attachment.
     void packColorResolveAttachment(size_t colorIndexGL);
 
     size_t hash() const;
 
     // Color attachments are in [0, colorAttachmentRange()), with possible gaps.
-    size_t colorAttachmentRange() const { return mColorAttachmentRange; }
+    size_t colorAttachmentRange() const;
     size_t depthStencilAttachmentIndex() const { return colorAttachmentRange(); }
 
     bool isColorAttachmentEnabled(size_t colorIndexGL) const;
-    bool hasDepthStencilAttachment() const { return mHasDepthStencilAttachment; }
+    bool hasDepthStencilAttachment() const
+    {
+        return getDepthStencilAccess() != ResourceAccess::Unused;
+    }
+    ResourceAccess getDepthStencilAccess() const;
     bool hasColorResolveAttachment(size_t colorIndexGL) const
     {
         return mColorResolveAttachmentMask.test(colorIndexGL);
@@ -107,8 +118,12 @@ class alignas(4) RenderPassDesc final
   private:
     // Store log(samples), to be able to store it in 3 bits.
     uint8_t mLogSamples : 3;
-    uint8_t mColorAttachmentRange : 4;
-    uint8_t mHasDepthStencilAttachment : 1;
+
+    // Color attachment count has 9 values: from 0-8 valid attachments. The depths/stencil
+    // attachment can have 3 values: no depth stencil, read only, and writable depth/stencil.
+    // We can pack these 9*3 = 27 possible values in 5 bits.
+    uint8_t mPackedColorAttachmentRangeAndDSAccess : 5;
+
     // Whether each color attachment has a corresponding resolve attachment.  Color resolve
     // attachments can be used to optimize resolve through glBlitFramebuffer() as well as support
     // GL_EXT_multisampled_render_to_texture and GL_EXT_multisampled_render_to_texture2.
@@ -900,6 +915,7 @@ class FramebufferDesc
     void updateColor(uint32_t index, ImageViewSubresourceSerial serial);
     void updateColorResolve(uint32_t index, ImageViewSubresourceSerial serial);
     void updateDepthStencil(ImageViewSubresourceSerial serial);
+    void updateReadOnlyDepth(bool readOnlyDepth);
     size_t hash() const;
     void reset();
 
@@ -911,7 +927,8 @@ class FramebufferDesc
     void update(uint32_t index, ImageViewSubresourceSerial serial);
 
     // Note: this is an exclusive index. If there is one index it will be "1".
-    uint32_t mMaxIndex;
+    uint16_t mMaxIndex;
+    uint16_t mReadOnlyDepth;
     FramebufferAttachmentArray<ImageViewSubresourceSerial> mSerials;
 };
 

src/libANGLE/renderer/vulkan/vk_helpers.cpp

@@ -344,6 +344,20 @@ constexpr angle::PackedEnumMap<ImageLayout, ImageMemoryBarrierData> kImageMemory
         },
     },
     {
+        ImageLayout::DepthStencilReadOnly,
+        {
+            VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL,
+            kAllShadersPipelineStageFlags | VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT,
+            kAllShadersPipelineStageFlags | VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT,
+            // Transition to: all reads and writes must happen after barrier.
+            VK_ACCESS_SHADER_READ_BIT | VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT,
+            // Transition from: all writes must finish before barrier.
+            0,
+            BarrierType::ReadOnly,
+            PipelineStage::EarlyFragmentTest,
+        },
+    },
+    {
         ImageLayout::DepthStencilAttachment,
         {
             VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL,
@@ -902,7 +916,7 @@ void CommandBufferHelper::addCommandDiagnostics(ContextVk *contextVk)
     if (mIsRenderPassCommandBuffer)
     {
         size_t attachmentCount             = mRenderPassDesc.attachmentCount();
-        size_t depthStencilAttachmentCount = mRenderPassDesc.hasDepthStencilAttachment();
+        size_t depthStencilAttachmentCount = mRenderPassDesc.hasDepthStencilAttachment() ? 1 : 0;
         size_t colorAttachmentCount        = attachmentCount - depthStencilAttachmentCount;
 
         std::string loadOps, storeOps;

src/libANGLE/renderer/vulkan/vk_helpers.h

@@ -1074,6 +1074,7 @@ enum class ImageLayout
     AllGraphicsShadersReadOnly,
     AllGraphicsShadersWrite,
     ColorAttachment,
+    DepthStencilReadOnly,
     DepthStencilAttachment,
     Present,