How to fix "hidden symbol `__gcov_init' in ../libgcov.a(_gcov.o) is referenced by DSO"

Problem

When we introduced Gocv to build my project for code coverage, I encountered the following error message:

error 1

g++     -m64 -z muldefs -L/lib64 -L/usr/lib64 -lglib-2.0 -m64 -DUV_64PORT -DU2_64_BUILD -fPIC -g  DU_starter.o
NFA_msghandle.o NFA_svr_exit.o du_err_printf.o  -L/workspace/code/myproject/src/home/x64debug/bin/
-L/workspace/code/myproject/src/home/x64debug/bin/lib/ -lundata -lutcallc_nfasvr
-Wl,-rpath=/workspace/code/myproject/src/home/x64debug/bin/ -Wl,-rpath=/.dulibs28  -Wl,--enable-new-dtags
-L/.dulibs28 -lodbc  -lm -lncurses -lrt -lcrypt -lgdbm -ldl -lpam -lpthread  -ldl -lglib-2.0
-lstdc++ -lnsl -lrt -lgcov -o /workspace/code/myproject/src/home/x64debug/objs/du/share/dutsvr
/usr/bin/ld: /workspace/code/myproject/src/home/x64debug/objs/du/share/dutsvr:
hidden symbol `__gcov_init' in /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcov.a(_gcov.o) is referenced by DSO

error 2

It may also be such an error

/home/p7539c/cutest/CuTest.c:379: undefined reference to `__gcov_init'
CuTest.o:(.data+0x184): undefined reference to `__gcov_merge_add'

Positioning problem

Let’s take the error 1.

From the error message, I noticed -lundata -lutcallc_nfasvr are all the linked libraries (-llibrary)

I checked libraries undata and utcallc_nfasvr one by one, and found it displayed U __gcov_init and U means undefined symbols.

Use the find command to search the library and the nm command to list symbols in the library.

-sh-4.2$ find -name *utcallc_nfasvr*
./bin/libutcallc_nfasvr.so
./objs/du/work/libutcallc_nfasvr.so
-sh-4.2$ nm ./bin/libutcallc_nfasvr.so | grep __gcov_init
                 U __gcov_init

How to fix

In my case, I just added the following code LIB_1_LIBS := -lgcov to allow the utcallc_nfasvr library to call gcov.

LIB_1 := utcallc_nfasvr
# added below code to my makefile
LIB_1_LIBS := -lgcov

Rebuild, the error is gone, then checked library, it displayed t __gcov_init this time, it means symbol value exists not hidden.

-sh-4.2$ nm ./bin/libutcallc_nfasvr.so | grep __gcov_init
                 t __gcov_init

Or in your case may build a shared library like so, similarly, just add the compile parameter -lgcov

g++   -shared -o libMyLib.so src_a.o src_b.o src_c.o -lgcov

Summary

I have encountered the following problems many times

undefined reference to `__gcov_init'

undefined reference to `__gcov_merge_add'

`hidden symbol `__gcov_init' in /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcov.a(_gcov.o) is referenced by DSO`

Each time I can fix it by adding -glcov then recompile. the error has gone after rebuild. (you use the nm command to double-check whether the symbol has been added successfully.)

Hopes it can help you.