static-analysis

静态分析

目的

指导 Agent 为 C/C++ 选择、运行和分类处理静态分析工具——clang-tidy、cppcheck 和 scan-build，包括抑制策略和 CI 集成。

触发条件

• “如何在我的项目上运行 clang-tidy？”
• “应该启用哪些 clang-tidy 检查？”
• “cppcheck 报告了误报——我该如何抑制它们？”
• “如何设置 scan-build 以进行更深入的分析？”
• “我的构建输出了大量静态分析警告”
• “如何为 clang-tidy 生成 compile_commands.json？”

工作流

1. 生成 compile_commands.json

clang-tidy 需要编译数据库：

# CMake (preferred)
cmake -S . -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
ln -s build/compile_commands.json .

# Bear (for Make-based projects)
bear -- make

# compiledb (alternative for Make)
pip install compiledb
compiledb make

2. 运行 clang-tidy

# Single file
clang-tidy src/foo.c -- -std=c11 -I include/

# Whole project via compile_commands.json
run-clang-tidy -p build/ -j$(nproc)

# With specific checks enabled
clang-tidy -checks='bugprone-*,modernize-*,performance-*' src/foo.cpp

# Apply auto-fixes
clang-tidy -checks='modernize-use-nullptr' -fix src/foo.cpp

3. 查看类别决策树

Goal?
├── Find real bugs            → bugprone-*, clang-analyzer-*
├── Modernise C++ code        → modernize-*
├── Follow core guidelines    → cppcoreguidelines-*
├── Catch performance issues  → performance-*
├── Security hardening        → cert-*, hicpp-*
└── Readability / style       → readability-*, llvm-*

类别	关键检查项	检查内容
bugprone-*	use-after-move、integer-division、suspicious-memset-usage	可能存在的错误
modernize-*	use-nullptr、use-override、use-auto	C++11/14/17 惯用法
cppcoreguidelines-*	avoid-goto、pro-bounds-*、no-malloc	C++ Core Guidelines
performance-*	unnecessary-copy-initialization、avoid-endl	性能回退
clang-analyzer-*	core.*、unix.*、security.*	路径敏感型错误
cert-*	err34-c、str51-cpp	CERT 编码标准

4. .clang-tidy 配置文件

# .clang-tidy — place at project root
Checks: >
  bugprone-*,
  modernize-*,
  performance-*,
  -modernize-use-trailing-return-type,
  -bugprone-easily-swappable-parameters
WarningsAsErrors: 'bugprone-*,clang-analyzer-*'
HeaderFilterRegex: '^(src|include)/.*'
CheckOptions:
  - key: modernize-loop-convert.MinConfidence
    value: reasonable
  - key: readability-identifier-naming.VariableCase
    value: camelCase

5. 抑制误报

// Suppress a single line
int result = riskyOp(); // NOLINT(bugprone-signed-char-misuse)

// Suppress a block
// NOLINTNEXTLINE(cppcoreguidelines-avoid-magic-numbers)
constexpr int BUFFER_SIZE = 4096;

// Suppress whole function
[[clang::suppress("bugprone-*")]]
void legacy_code() { /* ... */ }

或者在 .clang-tidy 中：

# Exclude third-party directories
HeaderFilterRegex: '^(src|include)/.*'
# Disable specific checks
Checks: '-bugprone-easily-swappable-parameters'

6. 运行 cppcheck

# Basic run
cppcheck --enable=all --std=c11 src/

# With compile_commands.json
cppcheck --project=build/compile_commands.json

# Include specific checks and suppress noise
cppcheck --enable=warning,performance,portability \
         --suppress=missingIncludeSystem \
         --suppress=unmatchedSuppression \
         --error-exitcode=1 \
         src/

# Generate XML report for CI
cppcheck --xml --xml-version=2 src/ 2> cppcheck-report.xml

--enable= 值	检查内容
warning	未定义行为、不良实践
performance	冗余操作、低效模式
portability	不具可移植性的构造
information	配置和使用说明
all	以上所有内容

7. 使用 scan-build 进行路径敏感分析

# Intercept a Make build
scan-build make

# Intercept CMake build
scan-build cmake --build build/

# Show HTML report
scan-view /tmp/scan-build-*/

# With specific checkers
scan-build -enable-checker security.insecureAPI.gets \
           -enable-checker alpha.unix.cstring.BufferOverlap \
           make

scan-build 能发现比 clang-tidy 更深层的问题：跨函数的释放后使用、逻辑错误导致的无效存储，以及复杂路径上的空指针解引用。

8. CI 集成

# GitHub Actions
- name: Static analysis
  run: |
    cmake -S . -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
    run-clang-tidy -p build -j$(nproc) -warnings-as-errors '*'

- name: cppcheck
  run: |
    cppcheck --enable=warning,performance \
             --suppress=missingIncludeSystem \
             --error-exitcode=1 \
             src/

有关 clang-tidy 检查项的详细信息，请参阅 references/clang-tidy-checks.md。

相关技能

• 使用 skills/compilers/clang 了解 Clang 工具链和诊断标志
• 使用 skills/compilers/gcc 将 GCC 警告作为补充分析
• 使用 skills/runtimes/sanitizers 配合静态分析检测运行时错误
• 使用 skills/build-systems/cmake 设置 CMAKE_EXPORT_COMPILE_COMMANDS