使用 string_view 编译 cpp 代码时 Coverity 报告错误

Question

我编译了一个简单的程序如下：

#include <iostream>
#include <string>
#include <string_view>

using namespace std;

int main(){

    char s[30] = "Hey there!";
    string_view sv(s, 7);

    cout<<"s: "<<s<<endl;
    cout<<"sv: "<<sv<<endl;
    return 0;
}

使用以下命令编译：

cov-build --dir idir --config /home/d3v/cov-analysis-linux64/config/coverity_config.xml g++ --std=c++17 dev.cpp -o dev

控制台上的结果：

Coverity Build Capture (64-bit) version 8.7.1 on Linux 3.10.0-514.21.1.el7.x86_64 x86_64
Internal version numbers: a59584cec3 p-lodi1-push-28091.44.570


[WARNING] Emitted 0 C/C++ compilation units (0%) successfully

0 C/C++ compilation units (0%) are ready for analysis
 For more details, please look at: 
    /home/d3v/d3v/idir/build-log.txt

build-log.txt 文件的尾部：

2020-09-14T11:34:00.997198Z|cov-build|19858|info|> Build time (cov-build overall): 00:00:02.288773
2020-09-14T11:34:00.997198Z|cov-build|19858|info|> 
2020-09-14T11:34:00.997678Z|cov-build|19858|info|> Build time (C/C++ emits total): 00:00:00.903396
2020-09-14T11:34:00.997678Z|cov-build|19858|info|> 
2020-09-14T11:34:00.997678Z|cov-build|19858|info|> 
2020-09-14T11:34:00.997725Z|cov-build|19858|info|> [WARNING] Emitted 0 C/C++ compilation units (0%) successfully
2020-09-14T11:34:00.997725Z|cov-build|19858|info|> 
2020-09-14T11:34:00.997725Z|cov-build|19858|info|> 0 C/C++ compilation units (0%) are ready for analysis
2020-09-14T11:34:00.997725Z|cov-build|19858|info|>  For more details, please look at: 
2020-09-14T11:34:00.997725Z|cov-build|19858|info|>     /home/d3v/d3v/idir/build-log.txt

构建错误-log.txt 文件：

[STATUS] Compiling dev.cpp
/home/d3v/cov-analysis-linux64/bin/cov-emit --dir=/home/d3v/d3v/idir --ignore_path=/tmp/cov-d3v/891bff16bbd88b7b80d27daaef3e5a81/cov-configure --ignore_path=/tmp/cov-d3v/891bff16bbd88b7b80d27daaef3e5a81/cov-d3v/2d94633aecadf2b164c84654240d09d0 --add_type_modifier=__coverity___fpreg --add_type_modifier=__coverity_decimal --no_predefined_feature_test_macros --no_stdarg_builtin --incompat_proto --no_predefined_cplusplus -w --no_predefines --comp_ver 8.3.1 --char_bit_size=8 --gnu_carriage_return_line_terminator --wchar_t_keyword --no_multiline_string --no_trigraphs --ignore_calling_convention --enable_80bit_float --enable_128bit_float --macro_stack_pragmas --exceptions --arg_dependent_overload --no_predefines --pre_preinclude /home/d3v/d3v/idir/emit/a7f5e15a0c55/config/988f58815e9372b14b5ed84fa4afe3d5/g++-config-0/coverity-macro-compat.h --pre_preinclude /home/d3v/d3v/idir/emit/a7f5e15a0c55/config/988f58815e9372b14b5ed84fa4afe3d5/g++-config-0/coverity-compiler-compat.h --preinclude /home/d3v/cov-analysis-linux64/config/template-g++-config-3/../user_nodefs.h --c++ --allow_incompat_throw --new_array_args --type_traits_helpers --c++14 --gnu_version 80301 --no_trigraphs --sys_include /opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../include/c++/8 --sys_include /opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../include/c++/8/x86_64-redhat-linux --sys_include /opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../include/c++/8/backward --sys_include /opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/include --sys_include /usr/local/include --sys_include /opt/rh/devtoolset-8/root/usr/include --sys_include /usr/include -D__NO_INLINE__ --type_sizes=e16Pdlx8fiw4s2 --type_alignments=e16Pdlx8fiw4s2 --size_t_type=m --ptrdiff_t_type=l dev.cpp
"/opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../includ
          e/c++/8/type_traits", line 1049: error #255: type name is not allowed
        : public __bool_constant<__is_assignable(_Tp, _Up)>
                                                 ^

"/opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../includ
          e/c++/8/type_traits", line 1049: error #255: type name is not allowed
        : public __bool_constant<__is_assignable(_Tp, _Up)>
                                                      ^

"/opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../includ
          e/c++/8/type_traits", line 1049: error #20: identifier
          "__is_assignable" is undefined
        : public __bool_constant<__is_assignable(_Tp, _Up)>
                                 ^

"/opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../includ
          e/c++/8/type_traits", line 2929: error #255: type name is not allowed
        remove_cv_t<remove_all_extents_t<_Tp>>
        ^

"/opt/rh/devtoolset-8/root/usr/lib/gcc/x86_64-redhat-linux/8/../../../../includ
          e/c++/8/type_traits", line 2928: error #20: identifier
          "__has_unique_object_representations" is undefined
      : bool_constant<__has_unique_object_representations(
                      ^

Emit for file '/home/d3v/d3v/dev.cpp' complete.
[ERROR] 5 errors detected in the compilation of "dev.cpp".
WARNING: cov-emit returned with code 1

生成了二进制文件，但我无法理解为什么 Coverity 报告错误并且 cov-emit 返回 1。请帮我解决这个问题。

OS: 分OS 7
gcc 版本：8.3.1

Answer 1

此类错误表明 Coverity 工具存在问题。 Coverity 编译器 cov-emit 无法编译本机编译器（在本例中为 GCC）接受的源代码。因此，它具有某种意想不到的不兼容性。

在这种情况下，我认为主要问题是 Coverity 版本比编译器旧，因此缺乏对它的支持。 GCC 8.3 was released in February 2019, while Coverity 8.7 was released in January 2017。对于每个新的受支持编译器版本，Coverity 团队可能需要针对该编译器及其捆绑的头文件进行特定调整。 Coverity 文档准确列出了支持的编译器版本。

因此，这提出了两种可能的解决方案：

使用更新的 Coverity 版本。
使用较旧的编译器，该编译器已在 Coverity 8.7 发布时正式支持。

协会免责声明：我曾经为Coverity/Synopsys工作。

使用 string_view 编译 cpp 代码时 Coverity 报告错误

Coverity reports error when compiling cpp code with string_view

c++

coverity

c++17