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
You could check for references to function
mcount (or possibly
__mcount according to Implementation of Profiling). This function is necessary for profiling to work, and should be absent for non-profiled binaries.
$ readelf -s someprog | egrep "\s(_+)?mcount\b" && echo "Profiling is on for someprog"
The above works on a quick test here.
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
Adding more to the answers:
To check for instrumentation, grep for mcount/gmon:
$ readelf -s <binary> | egrep "gmon|mcount" 20: 0000000000401160 63 FUNC GLOBAL DEFAULT 12 __gmon_start__ 28: 0000000000000000 0 FUNC GLOBAL DEFAULT UND mcount@GLIBC_2.2.5 (2) 36: 0000000000000000 0 FILE LOCAL DEFAULT ABS gmon-start.c 39: 00000000004011a0 0 FUNC LOCAL DEFAULT 12 call_gmon_start 100: 0000000000401160 63 FUNC GLOBAL DEFAULT 12 __gmon_start__ 114: 0000000000000000 0 FUNC GLOBAL DEFAULT UND mcount@@GLIBC_2.2.5
One needs to compile as well as link with
gmon.outwill not be generated. stackoverflow link.
I found that the binary on which I was running gprof didn't generate any
gmon.outfile, despite compiling/linking with
-pgflag. The reason being - I was killing my application, it wasn't a clean exit.
gprofgenerates output only when the program exits normally. stackoverflow link