According to what you have said that you've done, you might be missing the actual coverage part. To the other linker flags item you need to add -lgcov, and similar to the flow_arcs flag, you need the GCC_GENERATE_TEST_COVERAGE_FILES flag to be yes, so that you can get your .gcov output file. I'm assuming you know where the file should be, but just for completeness it should be here:
${PROJECT_DIR}/build/${PRODUCT_NAME}.build/${CONFIGURATION}-${PLATFORM_NAME}/${PRODUCT_NAME}.build/Objects-normal
I have found http://www.cubiclemuses.com/cm/articles/2009/05/14/coverstory-on-the-iphone/ to be a useful resource here.
I'm just getting into this stuff also, so, anyone, feel free to add to my answer.
TahoeWolverine
2009-07-31 03:05:33