diff --git a/.gitignore b/.gitignore
index 0f95955b..6f874262 100644
--- a/.gitignore
+++ b/.gitignore
@@ -64,6 +64,12 @@ cmake-build-release/
 .DS_Store
 Thumbs.db
 
+# =========================
+# Local-only (not for grader)
+# =========================
+include
+third_party/antlr4-runtime-4.13.2/runtime/
+
 # =========================
 # Project outputs
 # =========================
diff --git a/CMakeLists.txt b/CMakeLists.txt
index df0a85fc..13c90ff3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,7 +24,6 @@ target_include_directories(build_options INTERFACE
   "${PROJECT_SOURCE_DIR}/src/include"
   "${PROJECT_SOURCE_DIR}/src"
   "${ANTLR4_GENERATED_DIR}"
-  # 兼容未使用 -Xexact-output-dir 时 ANTLR 可能生成到的子目录结构
   "${ANTLR4_GENERATED_DIR}/src/antlr4"
 )
 
@@ -39,11 +38,32 @@ endif()
 
 option(COMPILER_PARSE_ONLY "Build only the frontend parser pipeline" OFF)
 
-# 仅链接系统线程库，antlr4 库将在链接阶段通过 -lantlr4-runtime 参数链接
-# 评测平台会提供必要的第三方库（如antlr4）
 find_package(Threads REQUIRED)
 
-# 设置 ANTLR4 运行时目标（评测平台通过 -lantlr4-runtime 提供）
-set(ANTLR4_RUNTIME_TARGET "antlr4-runtime")
+set(ANTLR4_RUNTIME_LOCAL_DIR "${PROJECT_SOURCE_DIR}/third_party/antlr4-runtime-4.13.2/runtime/src")
+if(EXISTS "${ANTLR4_RUNTIME_LOCAL_DIR}/antlr4-runtime.h")
+  set(ANTLR4_RUNTIME_SRC_DIR "${ANTLR4_RUNTIME_LOCAL_DIR}")
+  add_library(antlr4_runtime STATIC)
+  target_compile_features(antlr4_runtime PUBLIC cxx_std_17)
+  target_include_directories(antlr4_runtime PUBLIC
+    "${ANTLR4_RUNTIME_SRC_DIR}"
+    "${ANTLR4_RUNTIME_SRC_DIR}/atn"
+    "${ANTLR4_RUNTIME_SRC_DIR}/dfa"
+    "${ANTLR4_RUNTIME_SRC_DIR}/internal"
+    "${ANTLR4_RUNTIME_SRC_DIR}/misc"
+    "${ANTLR4_RUNTIME_SRC_DIR}/support"
+    "${ANTLR4_RUNTIME_SRC_DIR}/tree"
+    "${ANTLR4_RUNTIME_SRC_DIR}/tree/pattern"
+    "${ANTLR4_RUNTIME_SRC_DIR}/tree/xpath"
+  )
+  file(GLOB_RECURSE ANTLR4_RUNTIME_SOURCES CONFIGURE_DEPENDS
+    "${ANTLR4_RUNTIME_SRC_DIR}/*.cpp"
+  )
+  target_sources(antlr4_runtime PRIVATE ${ANTLR4_RUNTIME_SOURCES})
+  target_link_libraries(antlr4_runtime PUBLIC Threads::Threads)
+  set(ANTLR4_RUNTIME_TARGET antlr4_runtime)
+else()
+  set(ANTLR4_RUNTIME_TARGET "antlr4-runtime")
+endif()
 
 add_subdirectory(src)
\ No newline at end of file