[midend]重构了src目录

src/frontend/CMakeLists.txt

@@ -0,0 +1,17 @@
+# src/frontend/CMakeLists.txt
+add_library(frontend_lib STATIC
+    SysYBaseVisitor.cpp
+    SysY.g4
+    SysYLexer.cpp
+    SysYParser.cpp
+    SysYVisitor.cpp
+)
+
+# 包含前端模块所需的头文件路径
+target_include_directories(frontend_lib PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}/../include/frontend # 前端头文件
+    ${ANTLR_RUNTIME}/runtime/src                    # ANTLR 运行时头文件
+)
+
+# 链接 ANTLR 运行时库
+target_link_libraries(frontend_lib PRIVATE antlr4_shared)