VideoCommon: add method to async shader compiler to clear pending/completed work (used on shutdown), this will in turn clear up any resources that the worker items may have held onto

Source/Core/VideoCommon/AsyncShaderCompiler.cpp

@@ -68,6 +68,19 @@ bool AsyncShaderCompiler::HasCompletedWork()
   return !m_completed_work.empty();
 }
 
+void AsyncShaderCompiler::ClearAllWork()
+{
+  {
+    std::lock_guard<std::mutex> guard(m_pending_work_lock);
+    m_pending_work.clear();
+  }
+
+  {
+    std::lock_guard<std::mutex> guard(m_completed_work_lock);
+    m_completed_work.clear();
+  }
+}
+
 bool AsyncShaderCompiler::WaitUntilCompletion(
     const std::function<void(size_t, size_t)>& progress_callback)
 {

Source/Core/VideoCommon/AsyncShaderCompiler.h

@@ -49,6 +49,9 @@ public:
   bool HasPendingWork();
   bool HasCompletedWork();
 
+  // Clears both pending and completed work
+  void ClearAllWork();
+
   // Calls progress_callback periodically, with completed_items, and total_items.
   // Returns false if interrupted.
   bool WaitUntilCompletion(const std::function<void(size_t, size_t)>& progress_callback);

Source/Core/VideoCommon/GraphicsModSystem/Runtime/CustomShaderCache.cpp

@@ -24,10 +24,16 @@ CustomShaderCache::CustomShaderCache()
 CustomShaderCache::~CustomShaderCache()
 {
   if (m_async_shader_compiler)
+  {
     m_async_shader_compiler->StopWorkerThreads();
+    m_async_shader_compiler->ClearAllWork();
+  }
 
   if (m_async_uber_shader_compiler)
+  {
     m_async_uber_shader_compiler->StopWorkerThreads();
+    m_async_uber_shader_compiler->ClearAllWork();
+  }
 }
 
 void CustomShaderCache::RetrieveAsyncShaders()

Source/Core/VideoCommon/ShaderCache.cpp

@@ -109,7 +109,10 @@ void ShaderCache::Shutdown()
   // This may leave shaders uncommitted to the cache, but it's better than blocking shutdown
   // until everything has finished compiling.
   if (m_async_shader_compiler)
+  {
     m_async_shader_compiler->StopWorkerThreads();
+    m_async_shader_compiler->ClearAllWork();
+  }
 
   ClosePipelineUIDCache();
 }