Installing gprof on Mac
If you run brew install -v binutils, you will see this output flying by:

*** This configuration is not supported in the following subdirectories:
     ld gas gprof
     (Any other directories should still work fine.)


In configure.ac there is

*-*-darwin*)
  noconfigdirs="$noconfigdirs ld gas gdb gprof"
  noconfigdirs="$noconfigdirs sim target-rda"
  ;;


So, gprof is not supported on OS X.

I think the preferred profiling tool is DTrace.