gcov support for glibc

[Palleti, Avinash Reddy]

Hi,

We are trying to get coverage analysis for glibc test cases, we tried below command to enable gcov support while building glibc.

CFLAGS="-ftest-coverage -fprofile-arcs -O2 -U_FORTIFY_SOURCE" CXXFLAGS="-ftest-coverage -fprofile-arcs" LD_FLAGS="-fprofile-arcs" ../configure --prefix=/opt/ --disable-werror  libc_cv_ctors_header=yes libc_cv_c_cleanup=yes

With this configure line, "make tests" was giving segmentation fault with not much information in coredump. Then we realized that there is no support for gcov in glibc (https://sourceware.org/ml/libc-help/2017-09/msg00031.html)
There are suggestions to use oprofile  but that just gives functional coverage, we are looking for line coverage.
Does anyone tried supporting gcov for glibc, if yes, please share the patches or give us pointers to work on the same.

Thanks,
Avinash