[llvm] [Offload] Add MPI Plugin (PR #90890)

[Joseph Huber via llvm-commits]

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@@ -0,0 +1,110 @@
+##===----------------------------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+##===----------------------------------------------------------------------===##
+#
+# Build a plugin for a MPI machine if available.
+#
+##===----------------------------------------------------------------------===##
+if (NOT(CMAKE_SYSTEM_PROCESSOR MATCHES "(x86_64)|(ppc64le)$" AND CMAKE_SYSTEM_NAME MATCHES "Linux"))
+  libomptarget_say("Not building MPI offloading plugin: only support MPI in Linux x86_64 or ppc64le hosts.")
+  return()
+elseif (NOT LIBOMPTARGET_DEP_LIBFFI_FOUND)
+  libomptarget_say("Not building MPI offloading plugin: libffi dependency not found.")
+  return()
+elseif(NOT LIBOMPTARGET_DEP_MPI_FOUND)
+  libomptarget_say("Not building MPI offloading plugin: MPI not found in system.")
+  return()
+endif()
+
+libomptarget_say("Building MPI NextGen offloading plugin.")
+
+# Create the library and add the default arguments.
+add_target_library(omptarget.rtl.mpi MPI)
+
+target_sources(omptarget.rtl.mpi PRIVATE
+  src/EventSystem.cpp
+  src/rtl.cpp
+)
+
+if(FFI_STATIC_LIBRARIES)
----------------
jhuber6 wrote:

I really want to be rid of `libffi` https://github.com/llvm/llvm-project/issues/88738. I ran into a snag doing it but I think it's better to just hack around what I have and try to improve it later.

https://github.com/llvm/llvm-project/pull/90890