Detect if an ELF binary was built with gprof instrumentation?

Question

Is it possible to check if given program was compiled with GNU gprof instrumentation, i.e. with '-pg' flag passed to both compiler and linker, without running it to check if it would generate a gmon.out file?

Answer 1

You could check for references to function mcount (or possibly _mcount or __mcount according to Implementation of Profiling). This function is necessary for profiling to work, and should be absent for non-profiled binaries.

Something like:

$ readelf -s someprog | egrep "\s(_+)?mcount\b" && echo "Profiling is on for someprog"

The above works on a quick test here.

Answer 2

The regular expression in the answer above doesn't always work...but the general idea of grepping for "mcount" in the output of 'readelf -s [binary]' is correct, I think