Explicitly pass desired backend to emulator

src/backend-selection/CMakeLists.txt

@@ -0,0 +1,23 @@
+file(GLOB_RECURSE SRC_FILES CONFIGURE_DEPENDS
+  *.cpp
+  *.hpp
+  *.rc
+)
+
+list(SORT SRC_FILES)
+
+add_library(backend-selection ${SRC_FILES})
+
+momo_assign_source_group(${SRC_FILES})
+
+target_include_directories(backend-selection INTERFACE "${CMAKE_CURRENT_LIST_DIR}")
+
+target_link_libraries(backend-selection PRIVATE
+  unicorn-emulator
+)
+
+if (MOMO_ENABLE_RUST_CODE)
+  target_link_libraries(backend-selection PRIVATE
+    icicle-emulator
+  )
+endif()

src/backend-selection/backend_selection.cpp

@@ -0,0 +1,23 @@
+#include "backend_selection.hpp"
+
+#include <string_view>
+#include <unicorn_x86_64_emulator.hpp>
+
+#if MOMO_ENABLE_RUST_CODE
+#include <icicle_x86_64_emulator.hpp>
+#endif
+
+using namespace std::literals;
+
+std::unique_ptr<x86_64_emulator> create_x86_64_emulator()
+{
+#if MOMO_ENABLE_RUST_CODE
+    const auto* env = getenv("EMULATOR_ICICLE");
+    if (env && (env == "1"sv || env == "true"sv))
+    {
+        return icicle::create_x86_64_emulator();
+    }
+#endif
+
+    return unicorn::create_x86_64_emulator();
+}

src/backend-selection/backend_selection.hpp

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <memory>
+#include <arch_emulator.hpp>
+
+std::unique_ptr<x86_64_emulator> create_x86_64_emulator();