Document --dynamic-list-data option for --coverage usage.

2018-02-05  Martin Liska  <mliska@suse.cz>

	PR gcov-profile/83879
	* doc/gcov.texi: Document necessity of --dynamic-list-data when
	using dlopen functionality.

From-SVN: r257383

gcc/ChangeLog

+2018-02-05  Martin Liska  <mliska@suse.cz>
+
+	PR gcov-profile/83879
+	* doc/gcov.texi: Document necessity of --dynamic-list-data when
+	using dlopen functionality.
+
 2018-02-05  Olga Makhotina  <olga.makhotina@intel.com>
 
 	* config/i386/avx512dqintrin.h (_mm_mask_range_sd, _mm_maskz_range_sd,

gcc/doc/gcov.texi

@@ -788,6 +788,8 @@ Instrumented applications use a static destructor with priority 99
 to invoke the @code{__gcov_dump} function. Thus @code{__gcov_dump}
 is executed after all user defined static destructors,
 as well as handlers registered with @code{atexit}.
+If an executable loads a dynamic shared object via dlopen functionality,
+@option{-Wl,--dynamic-list-data} is needed to dump all profile data.
 
 @c man end