video_core: Initial implementation of pipeline cache (#3816)

* Initial implementation

* Fix for crash caused by stale stages data; cosmetics applied

* Someone mentioned the assert

* Async blob writer

* Fix for memory leak

* Remain stuff

* Async changed to `packaged_task`

src/shader_recompiler/ir/passes/srt.h

@@ -7,9 +7,14 @@
 #include <boost/container/small_vector.hpp>
 #include "common/types.h"
 
+namespace Serialization {
+struct Archive;
+}
+
 namespace Shader {
 
 using PFN_SrtWalker = void PS4_SYSV_ABI (*)(const u32* /*user_data*/, u32* /*flat_dst*/);
+PFN_SrtWalker RegisterWalkerCode(const u8* ptr, size_t size);
 
 struct PersistentSrtInfo {
     // Special case when fetch shader uses step rates.
@@ -20,7 +25,11 @@ struct PersistentSrtInfo {
     };
 
     PFN_SrtWalker walker_func{};
+    size_t walker_func_size{};
     u32 flattened_bufsize_dw = 16; // NumUserDataRegs
+
+    void Serialize(Serialization::Archive& ar) const;
+    bool Deserialize(Serialization::Archive& ar);
 };
 
 } // namespace Shader