cppcheck/man/chapters/09-speedup.md

Speeding up Cppcheck

It is possible to speed up Cppcheck analysis in a few different ways.

Preprocessor configurations

Imagine this source code:

void foo()
{
    int x;
#ifdef __GNUC__
    x = 0;
#endif
#ifdef _MSC_VER
    x = 1;
#endif
    return x;
}

By default Cppcheck will try to check all the configurations. There are 3 important configurations here:

• Neither __GNUC__ nor _MSC_VER is defined
• __GNUC__ is defined
• _MSC_VER is defined

When you run Cppcheck, the output will be something like:

$ cppcheck test.c
Checking test.c ...
[test.c:10]: (error) Uninitialized variable: x
Checking test.c: __GNUC__...
Checking test.c: _MSC_VER...

Now if you want you can limit the analysis. You probably know what the target compiler is. If -D is supplied and you do not specify --force then Cppcheck will only check the configuration you give.

$ cppcheck -D __GNUC__ test.c
Checking test.c ...
Checking test.c: __GNUC__=1...

Unused templates

If you think Cppcheck is slow and you are using templates, then you should try how it works to remove unused templates.

Imagine this code:

template <class T> struct Foo {
    T x = 100;
};

template <class T> struct Bar {
    T x = 200 / 0;
};

int main() {
    Foo<int> foo;
    return 0;
}

Cppcheck says:

$ cppcheck test.cpp
Checking test.cpp ...
[test.cpp:7]: (error) Division by zero.

It complains about division by zero in Bar even though Bar is not instantiated.

You can use the option --remove-unused-templates to remove unused templates from Cppcheck analysis.

Example:

$ cppcheck --remove-unused-templates test.cpp
Checking test.cpp ...

This lost message is in theory not critical, since Bar is not instantiated the division by zero should not occur in your real program.

The speedup you get can be remarkable.

Check headers

TBD