gprof output is empty

Question

Using gprof 2.28 and gcc 6.3.0 in Ubuntu 17.04 on a variety of sample programs I get empty output for every category. If I run gprof -i on one example program I get:

1 histogram record
2 call-graph records
0 basic-block count records

My compilation looks something like this:

cc -g -c sem_test.c -pg
cc -o sem_test sem_test.o -lpthread -pg

Or this:

gcc -g3 -O0 -Wall -std=gnu99 -pg -fprofile-arcs -fno-inline -fno-reorder-functions sem_test.c -o sem_test -lpthread -pg

Both have the same results.

I notice that my gmon.out file is only 687 bytes which seems low.

Answer 1

This is a glibc bug/limitation:

• -pg -pie doesn't work

If you cannot install a fixed glibc, you can link with -no-pie to disable PIE. Your toolchain probably enables PIE automatically.