How to use gcov with gcc without the optimization?

Question

I have a test code like this:

int diff21(int n)
{
    if (n <= 21)
    {
        return 21 - n;
    }
    else
    {
        return (n - 21) * 2;
    }
}

and I added the compile flags: -fprofile-arcs -ftest-coverage to provide coverage data.

I wrote the test code like this:

CU_ASSERT(diff21(19) == 2);

and I used lcov to generate a html report, and it said the else branch's return (n - 21) * 2 is excuted, so I got a 100% line coverage. This is not true

I googled and found that is because of this --- the gcc optimization can eliminate some simple code lines by combining them with other lines, but how should I generate the coverage data if I'm not supposed to use the -fprofile-arcs -ftest-coverage flag?

btw I'm using netbeans and cygwin to do unit tests, I don't think manually calling gcov in a makefile or script is good for me.

just for your information, I'm using lcov like this:

#!/bin/bash

rm -rf coverage_report
rm -f app.info

lcov -b . -d . -c -o app.info
mkdir coverage_report
genhtml --legend --highlight -o coverage_report app.info
rm -f app.info
lcov -d . -z

How to use gcov with gcc without the optimization?

0 Answers0