This is part of a set of patches implementing OMPT target callback support and has been split out of the originally submitted https://reviews.llvm.org/D113728. The overall design can be found in https://rice.app.box.com/s/pf3gix2hs4d4o1aatwir1set05xmjljc
The purpose of this patch is to provide a way to register tool-provided callbacks into libomp when libomptarget is loaded.
Introduced a cmake variable LIBOMPTARGET_OMPT_SUPPORT that can be used to control OMPT target support. It follows host OMPT support, controlled by LIBOMP_HAVE_OMPT_SUPPORT.
Added a connector that can be used to communicate between OMPT implementations in libomp and libomptarget or libomptarget and a plugin.
Added a global constructor in libomptarget that uses the connector to force registration of tool-provided callbacks in libomp. A pair of init and fini functions are provided to libomp as part of the connect process which will be used to register the tool-provided callbacks in libomptarget.
Patch from John Mellor-Crummey <firstname.lastname@example.org>
(With contributions from Dhruva Chakrabarti <Dhruva.Chakrabarti@amd.com>)