in helpers/trace_helpers.c [604:615]
static int dso__load_sym_table(struct dso *dso)
{
if (dso->type == UNKNOWN)
return -1;
if (dso->type == PERF_MAP)
return dso__load_sym_table_from_perf_map(dso);
if (dso->type == EXEC || dso->type == DYN)
return dso__load_sym_table_from_elf(dso, 0);
if (dso->type == VDSO)
return dso__load_sym_table_from_vdso_image(dso);
return -1;
}