Fixes the main issue in PR41693
When both modes are used, two functions are created:
sancov.module_ctor, sancov.module_ctor.$LastUnique, where
$LastUnique is the current LastUnique counter that may be different in
sancov.module_ctor.$LastUnique belongs to the comdat group of the same
name (due to the non-null third field of the ctor in llvm.global_ctors).
COMDAT group section [ 9] `.group' [sancov.module_ctor] contains 6 sections: [Index] Name [ 10] .text.sancov.module_ctor [ 11] .rela.text.sancov.module_ctor [ 12] .text.sancov.module_ctor.6 [ 13] .rela.text.sancov.module_ctor.6 [ 23] .init_array.2 [ 24] .rela.init_array.2 # 2 problems: # 1) If sancov.module_ctor in this module is discarded, this group # has a relocation to a discarded section. ld.bfd and gold will # error. (Another issue: it is silently accepted by lld) # 2) The comdat group has an unstable name that may be different in # another translation unit. Even if the linker allows the dangling relocation # (with --noinhibit-exec), there will be many undesired .init_array entries COMDAT group section [ 25] `.group' [sancov.module_ctor.6] contains 2 sections: [Index] Name [ 26] .init_array.2 [ 27] .rela.init_array.2
By using different module ctor names, the associated comdat group names
will also be different and thus stable across modules.