This generates an executable compiled with g++ with
gprof profiling enabled

to build enter
make
at the command prompt

This builds a gcc executable with
coverage analysis switched on, which might be some help here.  Takes a
long while to compile, but seems to run not too much more slowly than
the standard version.  

The runs generate a load of files with ".gcda" extension , which build
up stats for all subsequent runs until they are deleted (so one could
look at coverage for the whole test suite).  

"make reset" will remove all these statistics files.

"make analyze" runs "gcov" itself, sending the coverage statistics for
all the routines calls (a lot of text...) to "coverage", and
generating ".gcov" files in the subdirectory which give line-by-line
execution counts.  It uses this output to print some basic coverage
statistics.

The following are useful for analysing the output from gprof
    grep "^ *-: *[1-9]" *.gcov | wc
    grep "^ *#" *.gcov | wc
    grep "^ *[1-9]" *.gcov | wc