DREDD Ignores False #if Directives, Potentially Resulting In Invalid Code During Compilation

[JonathanFoo0523]

Steps To Reproduce:

int main() {
    int foo;
    foo = 1
    #if BAR
        | 19
    #endif
        ;
}

After running DREDD on the above file(named baz.c), compiling with clang baz.c -DBAR results in syntax error.

[afd]

This is actually expected behaviour. At mutation time, Dredd accepts a compilation database, specifying which compiler options - such as -D and -I options - should be used to process the source file. It processes the source file in the context of those options, and thus mutates for one particular set of preprocessor symbols.

You cannot later compile the mutated code with different preprocessor symbols.

This is a good post on compilation databases:

https://eli.thegreenplace.net/2014/05/21/compilation-databases-for-clang-based-tools