shader: Add pools and rename files

src/shader_recompiler/object_pool.h

@@ -0,0 +1,89 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <type_traits>
+
+namespace Shader {
+
+template <typename T, size_t chunk_size = 8192>
+requires std::is_destructible_v<T> class ObjectPool {
+public:
+    ~ObjectPool() {
+        std::unique_ptr<Chunk> tree_owner;
+        Chunk* chunk{&root};
+        while (chunk) {
+            for (size_t obj_id = chunk->free_objects; obj_id < chunk_size; ++obj_id) {
+                chunk->storage[obj_id].object.~T();
+            }
+            tree_owner = std::move(chunk->next);
+            chunk = tree_owner.get();
+        }
+    }
+
+    template <typename... Args>
+    requires std::is_constructible_v<T, Args...> [[nodiscard]] T* Create(Args&&... args) {
+        return std::construct_at(Memory(), std::forward<Args>(args)...);
+    }
+
+    void ReleaseContents() {
+        Chunk* chunk{&root};
+        if (chunk) {
+            const size_t free_objects{chunk->free_objects};
+            if (free_objects == chunk_size) {
+                break;
+            }
+            chunk->free_objects = chunk_size;
+            for (size_t obj_id = free_objects; obj_id < chunk_size; ++obj_id) {
+                chunk->storage[obj_id].object.~T();
+            }
+            chunk = chunk->next.get();
+        }
+        node = &root;
+    }
+
+private:
+    struct NonTrivialDummy {
+        NonTrivialDummy() noexcept {}
+    };
+
+    union Storage {
+        Storage() noexcept {}
+        ~Storage() noexcept {}
+
+        NonTrivialDummy dummy{};
+        T object;
+    };
+
+    struct Chunk {
+        size_t free_objects = chunk_size;
+        std::array<Storage, chunk_size> storage;
+        std::unique_ptr<Chunk> next;
+    };
+
+    [[nodiscard]] T* Memory() {
+        Chunk* const chunk{FreeChunk()};
+        return &chunk->storage[--chunk->free_objects].object;
+    }
+
+    [[nodiscard]] Chunk* FreeChunk() {
+        if (node->free_objects > 0) {
+            return node;
+        }
+        if (node->next) {
+            node = node->next.get();
+            return node;
+        }
+        node->next = std::make_unique<Chunk>();
+        node = node->next.get();
+        return node;
+    }
+
+    Chunk* node{&root};
+    Chunk root;
+};
+
+} // namespace Shader