Question

tldr;＆GT;如何在clang-tidy中隐藏系统标题中的警告？

我有以下最小的示例源文件，它会在系统标题中触发一个铿锵的警告：

#include <future>

int main() {
  std::promise<int> p;
  p.set_value(3);
}

在Ubuntu 17.04上使用clang-tidy 4.0.0使用libstdc ++ 7.0.1调用它：

$ clang-tidy main.cpp -extra-arg=-std=c++14

产量

Running without flags.
1 warning generated.
/usr/lib/gcc/x86_64-linux-gnu/7.0.1/../../../../include/c++/7.0.1/mutex:693:5: warning: Address of stack memory associated with local variable '__callable' is still referred to by the global variable '__once_callable' upon returning to the caller.  This will be a dangling reference [clang-analyzer-core.StackAddressEscape]
    }
    ^
/home/user/main.cpp:5:3: note: Calling 'promise::set_value'
  p.set_value(3);
  ^
/usr/lib/gcc/x86_64-linux-gnu/7.0.1/../../../../include/c++/7.0.1/future:1094:9: note: Calling '_State_baseV2::_M_set_result'
      { _M_future->_M_set_result(_State::__setter(this, std::move(__r))); }
        ^
/usr/lib/gcc/x86_64-linux-gnu/7.0.1/../../../../include/c++/7.0.1/future:401:2: note: Calling 'call_once'
        call_once(_M_once, &_State_baseV2::_M_do_set, this,
        ^
/usr/lib/gcc/x86_64-linux-gnu/7.0.1/../../../../include/c++/7.0.1/mutex:691:11: note: Assuming '__e' is 0
      if (__e)
          ^
/usr/lib/gcc/x86_64-linux-gnu/7.0.1/../../../../include/c++/7.0.1/mutex:691:7: note: Taking false branch
      if (__e)
      ^
/usr/lib/gcc/x86_64-linux-gnu/7.0.1/../../../../include/c++/7.0.1/mutex:693:5: note: Address of stack memory associated with local variable '__callable' is still referred to by the global variable '__once_callable' upon returning to the caller.  This will be a dangling reference
    }

我想在系统标头中隐藏警告。我尝试了以下方法：

$ clang-tidy -extra-arg=-std=c++14 main.cpp -header-filter=$(realpath .) -system-headers=0

但警告仍显示。

Answer 1

我最初得出的结论是这是不可能的，但是我有一个非常接近的黑客。

编译时，我使用CMAKE_EXPORT_COMPILE_COMMANDS = ON生成一个compile_commands.json文件，该文件显示了每个编译的cpp文件传递给编译器的命令。运行clang-tidy时，我给它提供-p选项，使其指向包含该文件的目录。

此文件中的典型条目如下所示：

{
  "directory": "/project/build/package1",
  "command": "/usr/bin/clang++-9 -I/opt/thirdparty/include -isystem /usr/include . . . /project/src/package1/src/foo.cpp",
  "file": "/project/src/package1/src/foo.cpp"
},

如果我重新编写此文件，以使-I/opt/thirdparty/include成为-isystem /opt/thirdparty/include，则/ opt / third-party / include中以前有问题的标头将被忽略，因为clang-tidy会将其视为系统标头。 / p>

我使用sed重写文件

# Trick clang-tidy into thinking anything in /opt/thirdparty/include is a system header
sed -i 's|-I/opt/thirdparty/include|-isystem /opt/thirdparty/include|g' build/compile_commands.json
# Run clang-tidy using the run-clang-tidy python wrapper
run-clang-tidy.py -p build -header-filter .* $(find src -iname "*.cpp")

Answer 2

我也遇到了这个问题，并且花了一些时间试图解决这个问题，但我找不到在铿锵声中禁用此类警告的方法。

从阅读this discussion on the LLVM issue tracker regarding a similar issue开始，我得到的印象是问题是从clang-tidy的角度来看，警告实际上位于main.cpp，因为set_value的调用来自那里

我的解决方法是在clang-tidy中禁用静态分析检查，并使用scan-build utility运行clang的静态分析，这似乎可以避免这些问题。例如，使用您的main.cpp：

$ scan-build-3.9 clang++ -std=c++14 main.cpp 
scan-build: Using '/usr/lib/llvm-3.9/bin/clang' for static analysis
In file included from main.cpp:1:
In file included from /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/future:39:
/usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/mutex:621:11: warning: Address of stack memory associated with local variable '__callable' is still referred to by the global variable '__once_callable' upon returning to the caller.  This will be a dangling reference
      if (__e)
          ^~~
1 warning generated.
scan-build: Removing directory '/tmp/scan-build-2017-12-02-112018-13035-1' because it contains no reports.
scan-build: No bugs found.

分析器在系统头中发现相同的错误，但它足够聪明，不能将其包含在最终报告中。（“没有发现错误”）

如果您对样式指南类型警告感兴趣，例如modernize-*或readability-*，您仍然需要单独运行clang-tidy。

在clang-tidy中忽略系统头

2 个答案: