diff --git a/src/frontend/AntlrDriver.cpp b/src/frontend/AntlrDriver.cpp
index 6a93e90..ee3c98c 100644
--- a/src/frontend/AntlrDriver.cpp
+++ b/src/frontend/AntlrDriver.cpp
@@ -9,20 +9,17 @@
 #include "SysYLexer.h"
 #include "SysYParser.h"
 #include "antlr4-runtime.h"
+#include "utils/Log.h"
 
 namespace {
 
-bool HasParsePrefix(const std::string& msg) {
-  return msg.rfind("[parse]", 0) == 0;
-}
-
 class ParseErrorListener : public antlr4::BaseErrorListener {
  public:
   void syntaxError(antlr4::Recognizer* /*recognizer*/, antlr4::Token* /*offendingSymbol*/,
                    size_t line, size_t charPositionInLine,
                    const std::string& msg, std::exception_ptr /*e*/) override {
-    throw std::runtime_error("[parse] 暂不支持的语法/词法 @" + std::to_string(line) + ":" +
-                             std::to_string(charPositionInLine) + " - " + msg);
+    throw std::runtime_error(FormatErrorAt("parse", line, charPositionInLine,
+                                           "暂不支持的语法/词法 - " + msg));
   }
 };
 
@@ -31,7 +28,7 @@ class ParseErrorListener : public antlr4::BaseErrorListener {
 AntlrResult ParseFileWithAntlr(const std::string& path) {
   std::ifstream fin(path);
   if (!fin.is_open()) {
-    throw std::runtime_error("[parse] 无法打开输入文件: " + path);
+    throw std::runtime_error(FormatError("parse", "无法打开输入文件: " + path));
   }
   std::ostringstream ss;
   ss << fin.rdbuf();
@@ -53,18 +50,18 @@ AntlrResult ParseFileWithAntlr(const std::string& path) {
   } catch (const std::exception& ex) {
     const std::string msg = ex.what();
     if (!msg.empty()) {
-      if (HasParsePrefix(msg)) {
+      if (HasErrorPrefix(msg, "parse")) {
         throw;
       }
-      throw std::runtime_error("[parse] 暂不支持的语法/词法 - " + msg);
+      throw std::runtime_error(
+          FormatError("parse", "暂不支持的语法/词法 - " + msg));
     }
     if (auto* tok = parser->getCurrentToken()) {
-      throw std::runtime_error("[parse] 暂不支持的语法/词法 @" +
-                               std::to_string(tok->getLine()) + ":" +
-                               std::to_string(tok->getCharPositionInLine()) +
-                               " near token '" + tok->getText() + "'");
+      throw std::runtime_error(
+          FormatErrorAt("parse", tok->getLine(), tok->getCharPositionInLine(),
+                        "暂不支持的语法/词法 near token '" + tok->getText() + "'"));
     }
-    throw std::runtime_error("[parse] 暂不支持的语法/词法");
+    throw std::runtime_error(FormatError("parse", "暂不支持的语法/词法"));
   }
 
   AntlrResult result;
diff --git a/src/main.cpp b/src/main.cpp
index da355f6..fafc646 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -52,7 +52,7 @@ int main(int argc, char** argv) {
       mir::PrintAsm(*machine_func, std::cout);
     }
   } catch (const std::exception& ex) {
-    std::cerr << "error: " << ex.what() << "\n";
+    PrintException(std::cerr, ex);
     return 1;
   }
   return 0;
diff --git a/src/utils/CLI.cpp b/src/utils/CLI.cpp
index 571750e..da8c2ba 100644
--- a/src/utils/CLI.cpp
+++ b/src/utils/CLI.cpp
@@ -5,17 +5,20 @@
 
 #include "utils/CLI.h"
 
+#include <cstring>
 #include <stdexcept>
 #include <string>
-#include <cstring>
+
+#include "utils/Log.h"
 
 CLIOptions ParseCLI(int argc, char** argv) {
   CLIOptions opt;
   bool explicit_emit = false;
 
   if (argc <= 1) {
-    throw std::runtime_error(
-        "用法: compiler [--help] [--emit-parse-tree] [--emit-ir] [--emit-asm] <input.sy>");
+    throw std::runtime_error(FormatError(
+        "cli",
+        "用法: compiler [--help] [--emit-parse-tree] [--emit-ir] [--emit-asm] <input.sy>"));
   }
 
   for (int i = 1; i < argc; ++i) {
@@ -59,23 +62,25 @@ CLIOptions ParseCLI(int argc, char** argv) {
     }
 
     if (arg[0] == '-') {
-      throw std::runtime_error(std::string("未知参数: ") + arg +
-                               "（使用 --help 查看用法）");
+      throw std::runtime_error(
+          FormatError("cli", std::string("未知参数: ") + arg +
+                                 "（使用 --help 查看用法）"));
     }
 
     if (!opt.input.empty()) {
-      throw std::runtime_error(
-          "参数过多：当前只支持 1 个输入文件（使用 --help 查看用法）");
+      throw std::runtime_error(FormatError(
+          "cli", "参数过多：当前只支持 1 个输入文件（使用 --help 查看用法）"));
     }
     opt.input = arg;
   }
 
   if (opt.input.empty() && !opt.show_help) {
-    throw std::runtime_error("缺少输入文件：请提供 <input.sy>（使用 --help 查看用法）");
+    throw std::runtime_error(
+        FormatError("cli", "缺少输入文件：请提供 <input.sy>（使用 --help 查看用法）"));
   }
   if (!opt.emit_parse_tree && !opt.emit_ir && !opt.emit_asm) {
-    throw std::runtime_error(
-        "未选择任何输出：请使用 --emit-parse-tree / --emit-ir / --emit-asm");
+    throw std::runtime_error(FormatError(
+        "cli", "未选择任何输出：请使用 --emit-parse-tree / --emit-ir / --emit-asm"));
   }
   return opt;
 }
diff --git a/src/utils/Log.cpp b/src/utils/Log.cpp
index 6f32e80..f5852f8 100644
--- a/src/utils/Log.cpp
+++ b/src/utils/Log.cpp
@@ -5,6 +5,48 @@
 #include "utils/Log.h"
 
 #include <ostream>
+#include <string>
+
+namespace {
+
+bool IsCLIError(const std::string_view msg) {
+  return HasErrorPrefix(msg, "cli");
+}
+
+}  // namespace
+
+void LogInfo(const std::string_view msg, std::ostream& os) {
+  os << "[info] " << msg << "\n";
+}
+
+void LogError(const std::string_view msg, std::ostream& os) {
+  os << "[error] " << msg << "\n";
+}
+
+std::string FormatError(const std::string_view stage,
+                        const std::string_view msg) {
+  return "[" + std::string(stage) + "] " + std::string(msg);
+}
+
+std::string FormatErrorAt(const std::string_view stage, const std::size_t line,
+                          const std::size_t column,
+                          const std::string_view msg) {
+  return "[" + std::string(stage) + "] @" + std::to_string(line) + ":" +
+         std::to_string(column) + " - " + std::string(msg);
+}
+
+bool HasErrorPrefix(const std::string_view msg, const std::string_view stage) {
+  const std::string prefix = "[" + std::string(stage) + "]";
+  return msg.rfind(prefix, 0) == 0;
+}
+
+void PrintException(std::ostream& os, const std::exception& ex) {
+  LogError(ex.what(), os);
+  if (IsCLIError(ex.what())) {
+    os << "\n";
+    PrintHelp(os);
+  }
+}
 
 void PrintHelp(std::ostream& os) {
   os << "SysY Compiler (课程实验最小可运行示例)\n"
diff --git a/src/utils/Log.h b/src/utils/Log.h
index ac15b2c..303f1a1 100644
--- a/src/utils/Log.h
+++ b/src/utils/Log.h
@@ -1,11 +1,20 @@
 // 轻量日志接口。
 #pragma once
 
+#include <cstddef>
+#include <exception>
 #include <iosfwd>
-#include <iostream>
+#include <string>
+#include <string_view>
 
-#define LOG_INFO(msg) std::cerr << "[info] " << msg << "\n"
-#define LOG_ERROR(msg) std::cerr << "[error] " << msg << "\n"
+void LogInfo(std::string_view msg, std::ostream& os);
+void LogError(std::string_view msg, std::ostream& os);
+
+std::string FormatError(std::string_view stage, std::string_view msg);
+std::string FormatErrorAt(std::string_view stage, std::size_t line,
+                          std::size_t column, std::string_view msg);
+bool HasErrorPrefix(std::string_view msg, std::string_view stage);
+void PrintException(std::ostream& os, const std::exception& ex);
 
 // 打印命令行帮助信息（用于 `compiler --help`）。
 void PrintHelp(std::ostream& os);