Question

Let’s say I have a program made of several “basic” algorithms on integral variables, such as :

if(a<b)
   a += c;

Is there a tool that would allow me to automatically log all the changes made to the different variables at run time?

For instance it would display in that case in a log file:

 "condition passed because 5=a < b=10
     a += 10; because c=10"

or some equivalent.

I am aware that I could manually log each operation but that would be much too complex.
Is there any tool that would allow me to do something like that? I don’t care about refactoring / recompiling as long as it’s not totally manual.

Answer 1

You can write your own integer class that overloads the operators accordingly (with automatic logging). If the class also provides implicit conversion (a constructor from int and a conversion operator to int), then you “only” need to change the types of variables and parameters to have your automatic logging of values. But instead of names you could only log addresses (or something derived from it like var20). With the help of a #define you could easily switch between raw ints (without logging) or your integer class with logging.

To get also the names of the variables into the logging one would either have to rewrite the operators with macros like

if (LESS(a,b))
    INC(a,c)

or have a parser that automatically transforms your code into something like this. But I am not aware of any existing tool providing this.