[dxvk] Ignore spec constants that are not used by the current pipeline

May reduce the number of pipeline permutations.

src/dxvk/dxvk_compute.h

@@ -90,6 +90,17 @@ namespace dxvk {
     DxvkBindingLayoutObjects* getBindings() const {
       return m_bindings;
     }
+
+    /**
+     * \brief Queries spec constant mask
+     *
+     * This only includes user spec constants.
+     * \returns Bit mask of used spec constants
+     */
+    uint32_t getSpecConstantMask() const {
+      constexpr uint32_t globalMask = (1u << MaxNumSpecConstants) - 1;
+      return m_shaders.cs->getSpecConstantMask() & globalMask;
+    }
     
     /**
      * \brief Retrieves pipeline handle

src/dxvk/dxvk_context.cpp

@@ -2524,24 +2524,6 @@ namespace dxvk {
   }
 
 
-  void DxvkContext::setSpecConstant(
-          VkPipelineBindPoint pipeline,
-          uint32_t            index,
-          uint32_t            value) {
-    auto& specConst = pipeline == VK_PIPELINE_BIND_POINT_GRAPHICS
-      ? m_state.gp.state.sc.specConstants[index]
-      : m_state.cp.state.sc.specConstants[index];
-    
-    if (specConst != value) {
-      specConst = value;
-
-      m_flags.set(pipeline == VK_PIPELINE_BIND_POINT_GRAPHICS
-        ? DxvkContextFlag::GpDirtyPipelineState
-        : DxvkContextFlag::CpDirtyPipelineState);
-    }
-  }
-  
-  
   void DxvkContext::setBarrierControl(DxvkBarrierControlFlags control) {
     m_barrierControl = control;
   }
@@ -4493,6 +4475,12 @@ namespace dxvk {
     if (unlikely(!newPipeline))
       return false;
 
+    if (unlikely(newPipeline->getSpecConstantMask() != m_state.cp.constants.mask))
+      this->resetSpecConstants<VK_PIPELINE_BIND_POINT_COMPUTE>(newPipeline->getSpecConstantMask());
+
+    if (m_flags.test(DxvkContextFlag::CpDirtySpecConstants))
+      this->updateSpecConstants<VK_PIPELINE_BIND_POINT_COMPUTE>();
+
     // Look up Vulkan pipeline handle for the given compute state
     auto pipelineHandle = newPipeline->getPipelineHandle(m_state.cp.state);
     
@@ -4545,6 +4533,9 @@ namespace dxvk {
       return false;
     }
 
+    if (unlikely(newPipeline->getSpecConstantMask() != m_state.gp.constants.mask))
+      this->resetSpecConstants<VK_PIPELINE_BIND_POINT_GRAPHICS>(newPipeline->getSpecConstantMask());
+
     if (m_state.gp.flags != newPipeline->flags()) {
       m_state.gp.flags = newPipeline->flags();
 
@@ -4656,6 +4647,49 @@ namespace dxvk {
   }
 
 
+  template<VkPipelineBindPoint BindPoint>
+  void DxvkContext::resetSpecConstants(
+          uint32_t                newMask) {
+    auto& scInfo  = BindPoint == VK_PIPELINE_BIND_POINT_GRAPHICS ? m_state.gp.state.sc  : m_state.cp.state.sc;
+    auto& scState = BindPoint == VK_PIPELINE_BIND_POINT_GRAPHICS ? m_state.gp.constants : m_state.cp.constants;
+
+    // Set all constants to 0 that were used by the previous pipeline
+    // but are not used by the old one. Any stale data could otherwise
+    // lead to unnecessary pipeline variants being created.
+    for (auto i : bit::BitMask(scState.mask & ~newMask))
+      scInfo.specConstants[i] = 0;
+
+    scState.mask = newMask;
+
+    auto flag = BindPoint == VK_PIPELINE_BIND_POINT_GRAPHICS
+      ? DxvkContextFlag::GpDirtySpecConstants
+      : DxvkContextFlag::CpDirtySpecConstants;
+
+    if (newMask)
+      m_flags.set(flag);
+    else
+      m_flags.clr(flag);
+  }
+
+
+  template<VkPipelineBindPoint BindPoint>
+  void DxvkContext::updateSpecConstants() {
+    auto& scInfo  = BindPoint == VK_PIPELINE_BIND_POINT_GRAPHICS ? m_state.gp.state.sc  : m_state.cp.state.sc;
+    auto& scState = BindPoint == VK_PIPELINE_BIND_POINT_GRAPHICS ? m_state.gp.constants : m_state.cp.constants;
+
+    for (auto i : bit::BitMask(scState.mask))
+      scInfo.specConstants[i] = scState.data[i];
+
+    if (BindPoint == VK_PIPELINE_BIND_POINT_GRAPHICS) {
+      m_flags.clr(DxvkContextFlag::GpDirtySpecConstants);
+      m_flags.set(DxvkContextFlag::GpDirtyPipelineState);
+    } else {
+      m_flags.clr(DxvkContextFlag::CpDirtySpecConstants);
+      m_flags.set(DxvkContextFlag::CpDirtyPipelineState);
+    }
+  }
+
+
   void DxvkContext::invalidateState() {
     this->unbindComputePipeline();
     this->unbindGraphicsPipeline();
@@ -5348,7 +5382,9 @@ namespace dxvk {
   bool DxvkContext::commitComputeState() {
     this->spillRenderPass(false);
 
-    if (m_flags.test(DxvkContextFlag::CpDirtyPipelineState)) {
+    if (m_flags.any(
+      DxvkContextFlag::CpDirtyPipelineState,
+      DxvkContextFlag::CpDirtySpecConstants)) {
       if (unlikely(!this->updateComputePipelineState()))
         return false;
     }
@@ -5397,6 +5433,9 @@ namespace dxvk {
     if (m_flags.test(DxvkContextFlag::GpDirtyVertexBuffers))
       this->updateVertexBufferBindings();
     
+    if (m_flags.test(DxvkContextFlag::GpDirtySpecConstants))
+      this->updateSpecConstants<VK_PIPELINE_BIND_POINT_GRAPHICS>();
+
     if (m_flags.test(DxvkContextFlag::GpDirtyPipelineState)) {
       DxvkGlobalPipelineBarrier barrier = { };
 

src/dxvk/dxvk_context.h

@@ -1033,7 +1033,20 @@ namespace dxvk {
     void setSpecConstant(
             VkPipelineBindPoint pipeline,
             uint32_t            index,
-            uint32_t            value);
+            uint32_t            value) {
+      auto& scState = pipeline == VK_PIPELINE_BIND_POINT_GRAPHICS
+        ? m_state.gp.constants : m_state.cp.constants;
+      
+      if (scState.data[index] != value) {
+        scState.data[index] = value;
+
+        if (scState.mask & (1u << index)) {
+          m_flags.set(pipeline == VK_PIPELINE_BIND_POINT_GRAPHICS
+            ? DxvkContextFlag::GpDirtySpecConstants
+            : DxvkContextFlag::CpDirtySpecConstants);
+        }
+      }
+    }
     
     /**
      * \brief Sets barrier control flags
@@ -1347,7 +1360,14 @@ namespace dxvk {
     void unbindGraphicsPipeline();
     bool updateGraphicsPipeline();
     bool updateGraphicsPipelineState(DxvkGlobalPipelineBarrier srcBarrier);
-    
+
+    template<VkPipelineBindPoint BindPoint>
+    void resetSpecConstants(
+            uint32_t                newMask);
+
+    template<VkPipelineBindPoint BindPoint>
+    void updateSpecConstants();
+
     void invalidateState();
 
     template<VkPipelineBindPoint BindPoint>

src/dxvk/dxvk_context_state.h

@@ -37,6 +37,7 @@ namespace dxvk {
     GpDirtyStencilRef,          ///< Stencil reference has changed
     GpDirtyRasterizerState,     ///< Cull mode and front face have changed
     GpDirtyViewport,            ///< Viewport state has changed
+    GpDirtySpecConstants,       ///< Graphics spec constants are out of date
     GpDynamicBlendConstants,    ///< Blend constants are dynamic
     GpDynamicDepthStencilState, ///< Depth-stencil state is dynamic
     GpDynamicDepthBias,         ///< Depth bias is dynamic
@@ -47,6 +48,7 @@ namespace dxvk {
     GpIndependentSets,          ///< Graphics pipeline layout was created with independent sets
     
     CpDirtyPipelineState,       ///< Compute pipeline is out of date
+    CpDirtySpecConstants,       ///< Compute spec constants are out of date
     
     DirtyDrawBuffer,            ///< Indirect argument buffer is dirty
     DirtyPushConstants,         ///< Push constant data has changed
@@ -120,11 +122,18 @@ namespace dxvk {
   };
   
   
+  struct DxvkSpecConstantState {
+    uint32_t                                  mask = 0;
+    std::array<uint32_t, MaxNumSpecConstants> data = { };
+  };
+  
+  
   struct DxvkGraphicsPipelineState {
     DxvkGraphicsPipelineShaders   shaders;
     DxvkGraphicsPipelineStateInfo state;
     DxvkGraphicsPipelineFlags     flags;
     DxvkGraphicsPipeline*         pipeline = nullptr;
+    DxvkSpecConstantState         constants;
   };
   
   
@@ -132,6 +141,7 @@ namespace dxvk {
     DxvkComputePipelineShaders    shaders;
     DxvkComputePipelineStateInfo  state;
     DxvkComputePipeline*          pipeline = nullptr;
+    DxvkSpecConstantState         constants;
   };
 
 

src/dxvk/dxvk_graphics.h

@@ -343,6 +343,17 @@ namespace dxvk {
       return m_bindings;
     }
 
+    /**
+     * \brief Queries spec constant mask
+     *
+     * This only includes user spec constants.
+     * \returns Bit mask of used spec constants
+     */
+    uint32_t getSpecConstantMask() const {
+      constexpr uint32_t globalMask = (1u << MaxNumSpecConstants) - 1;
+      return m_specConstantMask & globalMask;
+    }
+
     /**
      * \brief Queries global resource barrier
      *