[dxvk] Always pre-compile compute shaders

We didn't initially do this because the pipeline library code
unconditionally used pNext chains to pass shader code. However,
shader module creation has since been refactored, and now there
is no good reason not to compile compute shaders immediately.

Also fix the stat counter while we're at it.

src/dxvk/dxvk_compute.cpp

@@ -35,18 +35,20 @@ namespace dxvk {
   
   VkPipeline DxvkComputePipeline::getPipelineHandle(
     const DxvkComputePipelineStateInfo& state) {
-    if (m_library) {
-      // For compute pipelines that can be precompiled, we can use that
-      // pipeline variant unconditionally since there is no state for us
-      // to worry about other than specialization constants
-      if (unlikely(!m_libraryHandle)) {
-        m_libraryHandle = m_library->getPipelineHandle(
-          DxvkShaderPipelineLibraryCompileArgs());
-        m_stats->numComputePipelines += 1;
-      }
+    if (m_libraryHandle) {
+      // Compute pipelines without spec constants are always
+      // pre-compiled, so we'll almost always hit this path
+      return m_libraryHandle;
+    } else if (m_library) {
+      // Retrieve actual pipeline handle on first use. This
+      // may wait for an ongoing compile job to finish, or
+      // compile the pipeline immediately on the calling thread.
+      m_libraryHandle = m_library->getPipelineHandle(
+        DxvkShaderPipelineLibraryCompileArgs());
 
       return m_libraryHandle;
     } else {
+      // Slow path for compute shaders that do use spec constants
       DxvkComputePipelineInstance* instance = this->findInstance(state);
 
       if (unlikely(!instance)) {

src/dxvk/dxvk_pipemanager.cpp

@@ -280,7 +280,7 @@ namespace dxvk {
   
   void DxvkPipelineManager::registerShader(
     const Rc<DxvkShader>&         shader) {
-    if (m_device->canUseGraphicsPipelineLibrary() && shader->canUsePipelineLibrary()) {
+    if (canPrecompileShader(shader)) {
       auto library = createPipelineLibrary(shader);
       m_workers.compilePipelineLibrary(library);
     }
@@ -380,5 +380,17 @@ namespace dxvk {
 
     return &pair->second;
   }
-  
+
+
+  bool DxvkPipelineManager::canPrecompileShader(
+    const Rc<DxvkShader>&     shader) const {
+    if (!shader->canUsePipelineLibrary())
+      return false;
+
+    if (shader->info().stage == VK_SHADER_STAGE_COMPUTE_BIT)
+      return true;
+
+    return m_device->canUseGraphicsPipelineLibrary();
+  }
+
 }

src/dxvk/dxvk_pipemanager.h

@@ -276,6 +276,9 @@ namespace dxvk {
     DxvkShaderPipelineLibrary* findPipelineLibrary(
       const Rc<DxvkShader>&     shader);
 
+    bool canPrecompileShader(
+      const Rc<DxvkShader>&     shader) const;
+
   };
   
 }

src/dxvk/dxvk_shader.cpp

@@ -502,17 +502,28 @@ namespace dxvk {
     if (pipeline)
       return pipeline;
 
+    bool usesDefaultArgs = (args == DxvkShaderPipelineLibraryCompileArgs());
+
     switch (stage) {
       case VK_SHADER_STAGE_VERTEX_BIT:
         pipeline = compileVertexShaderPipeline(args);
+
+        if (usesDefaultArgs)
+          m_stats->numGraphicsLibraries += 1;
         break;
 
       case VK_SHADER_STAGE_FRAGMENT_BIT:
         pipeline = compileFragmentShaderPipeline();
+
+        if (usesDefaultArgs)
+          m_stats->numGraphicsLibraries += 1;
         break;
 
       case VK_SHADER_STAGE_COMPUTE_BIT:
         pipeline = compileComputeShaderPipeline();
+
+        if (usesDefaultArgs)
+          m_stats->numComputePipelines += 1;
         break;
 
       default:
@@ -520,9 +531,6 @@ namespace dxvk {
         return VK_NULL_HANDLE;
     }
 
-    if (args == DxvkShaderPipelineLibraryCompileArgs())
-      m_stats->numGraphicsLibraries += 1;
-
     return pipeline;
   }