feat: move allocator and slots into codegen folder

include/codegen/slot.hpp

@@ -0,0 +1,48 @@
+#pragma once
+#include "prelude/string.hpp"
+
+namespace IR
+{
+
+struct IRSlot
+{
+    enum class Type
+    {
+        UNKNOWN = 0,
+        STACK,
+        REGISTRY,
+    };
+public:
+    IRSlot(StringView addr, unsigned int slot, Type slotType) : m_addr(addr), m_slot(slot), m_slotType(slotType) {}
+    IRSlot() = default;
+public:
+    Type GetType() const { return m_slotType; }
+    const StringView& GetAddr() const { return m_addr; }
+    unsigned int GetSlot() const { return m_slot; }
+public:
+    StringView Format() const {
+        StringBuilder sb;
+        switch(GetType())
+        {
+        case Type::REGISTRY:
+            sb << "r" << GetSlot();
+            break;
+        case Type::STACK:
+            sb << "s[" << GetSlot() << "]";
+            break;
+        default:
+            sb << "(UNKNOWN_SLOT_TYPE)";
+            break;
+        }
+        return sb.view();
+    }
+private:
+    StringView m_addr;
+    unsigned int m_slot;
+    Type m_slotType;
+};
+
+using IRSlotBuilder = Builder<IRSlot>;
+using IRSlotView = View<IRSlot>;
+
+} // namespace IR