4be3e95284
The Offload and Flang-RT had the ability to compile GTest themselves. But in bootstrapping builds, LLVM_LIBRARY_OUTPUT_INTDIR points to the same location as the stage1 build. If both are building GTest, they everwrite each others `libllvm_gtest.a` and `libllvm_test_main.a` which causes #143134. This PR removes the ability for the Offload/Flang-RT runtimes to build their own GTest and instead relies on the stage1 build of GTest. This was already the case with LLVM_INSTALL_GTEST=ON configurations. For LLVM_INSTALL_GTEST=OFF configurations, we now also export gtest into the buildtree configuration. Ultimately, this reduces combinatorial explosion of configurations in which unittests could be built (LLVM_INSTALL_GTEST=ON, GTest built by Offload, GTest built by Flang-RT, GTest built by Offload and also used by Flang-RT). GTest and therefore Offload/Runtime unittests will not be available if the runtimes are configured against an LLVM install tree. Since llvm-lit isn't available in the install tree either, it doesn't matter. Note that compiler-rt and libc also use GTest in non-default configrations. libc also depends on LLVM's GTest build (and would error-out if unavailable), but compiler-rt builds it completely different. Fixes #143134
The LLVM/Offload Subproject
The Offload subproject aims at providing tooling, runtimes, and APIs that allow users to execute code on accelerators or other "co-processors" that may or may not match the architecture of their "host". In the long run, all kinds of targets are in scope of this effort, including but not limited to: CPUs, GPUs, FPGAs, AI/ML accelerators, distributed resources, etc.
For OpenMP offload users, the project is ready and fully usable. The final API design is still under development. More content will show up here and on our webpage soon. In the meantime, people are encouraged to participate in our meetings (see below) and check our development board as well as the discussions on Discourse.
Meetings
Every second Wednesday, 7:00 - 8:00am PT, starting Jan 24, 2024. Alternates with the OpenMP in LLVM meeting. invite.ics Meeting Minutes and Agenda