[Bug debug/68771] Darwin: Profile guided optimisation with cold sections and invalid symbol redefinition

[zerolo at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68771

--- Comment #10 from Daniel Vollmer <zerolo at gmail dot com> ---
Created attachment 46036
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46036&action=edit
Example triggering "This was likely caused by different translation units being
compiled with different visibility settings."

Generates (w/ g++-7.4 on Darwin)

ld: warning: direct access in function '__GLOBAL__sub_I_65535_0_test.cpp' from
file
'/var/folders/02/yl3m8d4d0397mk6dxn6dpcqw0000gp/T//ccuYv6qu.ltrans0.ltrans.o'
to global weak symbol '__ZGVZ19BroadcastFromMasterImEvPT_mE4bufs' from file
'/var/folders/02/yl3m8d4d0397mk6dxn6dpcqw0000gp/T//ccuYv6qu.ltrans0.ltrans.o'
means the weak symbol cannot be overridden at runtime. This was likely caused
by different translation units being compiled with different visibility
settings.