[libomptarget] Change nvcc compilation to use a unity build

JonChesterfield · JonChesterfield · commit e9f9dfab82bb · 2019-10-31T01:58:51.000Z
Summary: [libomptarget] Change nvcc compilation to use a unity build This allows nvcc to inline functions between what would otherwise be distinct translation units, which in turn removes any runtime cost from implementing functions in source files (as opposed to inline in headers). This will then allow the circular dependencies in deviceRTL to be readily broken and individual components more easily shared between architectures. Reviewers: ABataev, jdoerfert, grokos, RaviNarayanaswamy, hfinkel, ronlieb, gregrodgers Reviewed By: jdoerfert Subscribers: mgorny, openmp-commits Tags: #openmp Differential Revision: https://reviews.llvm.org/D69489
diff --git a/openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt b/openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
@@ -88,7 +88,7 @@ if(LIBOMPTARGET_DEP_CUDA_FOUND)
   set(BUILD_SHARED_LIBS OFF)
   set(CUDA_SEPARABLE_COMPILATION ON)
   list(APPEND CUDA_NVCC_FLAGS -I${devicertl_base_directory})
-  cuda_add_library(omptarget-nvptx STATIC ${cuda_src_files} ${omp_data_objects}
+  cuda_add_library(omptarget-nvptx STATIC unity.cu
       OPTIONS ${CUDA_ARCH} ${CUDA_DEBUG})
 
   # Install device RTL under the lib destination folder.
diff --git a/openmp/libomptarget/deviceRTLs/nvptx/unity.cu b/openmp/libomptarget/deviceRTLs/nvptx/unity.cu
@@ -0,0 +1,25 @@
+//===------ unity.cu - Unity build of NVPTX deviceRTL ------------ CUDA -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Support compilers, specifically NVCC, which have not implemented link time
+// optimisation. This removes the runtime cost of moving inline functions into
+// source files in exchange for preventing efficient incremental builds.
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/cancel.cu"
+#include "src/critical.cu"
+#include "src/data_sharing.cu"
+#include "src/libcall.cu"
+#include "src/loop.cu"
+#include "src/omp_data.cu"
+#include "src/omptarget-nvptx.cu"
+#include "src/parallel.cu"
+#include "src/reduction.cu"
+#include "src/sync.cu"
+#include "src/task.cu"
