Summary:
Currently, a linker option must be used to control the backend
parallelism of ThinLTO. The linker option varies depending on the
linker (e.g. gold vs ld64). Add a new clang option -flto-jobs=N
to control this.
I've added in the wiring to pass this to the gold plugin. I also
added in the logic to pass this down in the form I understand that
ld64 uses on MacOS, for the darwin target.
Reviewers: mehdi_amini, dexonsmith
Subscribers: mehdi_amini, cfe-commits
Differential Revision: https://reviews.llvm.org/D24826
llvm-svn: 282291