[Openmp-commits] [PATCH] D94573: [OpenMP] Drop the static library libomptarget-nvptx

[Shilei Tian via Phabricator via Openmp-commits]

tianshilei1992 created this revision.
tianshilei1992 added reviewers: jdoerfert, JonChesterfield, ABataev, grokos.
Herald added subscribers: guansong, yaxunl, mgorny.
tianshilei1992 requested review of this revision.
Herald added subscribers: openmp-commits, sstefan1.
Herald added a project: OpenMP.

For NVPTX target, OpenMP provides a static library `libomptarget-nvptx`
built by NVCC, and another bitcode `libomptarget-nvptx-sm_{$sm}.bc` generated by
Clang. When compiling an OpenMP program, the `.bc` file will be fed to `clang`
in the second run on the program that compiles the target part. Then the generated
PTX file will be fed to `ptxas` to generate the object file, and finally the driver
invokes `nvlink` to generate the binary, where the static library will be appened
to `nvlink`.

One question is, why do we need two libraries? The only difference is, the static
library contains `omp_data.cu` and the bitcode library doesn't. It's unclear why
they were implemented in this way, but per D94565 <https://reviews.llvm.org/D94565>, there is no issue if we also
include the file into the bitcode library. Therefore, we can safely drop the
static library.

This patch is about the change in OpenMP. The driver will be updated as well if
this patch is accepted.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94573

Files:
  openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt


Index: openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
===================================================================
--- openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
+++ openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
@@ -56,6 +56,7 @@
       ${devicertl_common_directory}/src/data_sharing.cu
       ${devicertl_common_directory}/src/libcall.cu
       ${devicertl_common_directory}/src/loop.cu
+      ${devicertl_common_directory}/src/omp_data.cu
       ${devicertl_common_directory}/src/omptarget.cu
       ${devicertl_common_directory}/src/parallel.cu
       ${devicertl_common_directory}/src/reduction.cu
@@ -65,8 +66,6 @@
       src/target_impl.cu
   )
 
-  set(omp_data_objects ${devicertl_common_directory}/src/omp_data.cu)
-
   # Build library support for the highest compute capability the system supports
   # and always build support for sm_35 by default
   if (${LIBOMPTARGET_DEP_CUDA_ARCH} EQUAL 35)
@@ -95,24 +94,6 @@
   # Activate RTL message dumps if requested by the user.
   set(LIBOMPTARGET_NVPTX_DEBUG FALSE CACHE BOOL
     "Activate NVPTX device RTL debug messages.")
-  if(${LIBOMPTARGET_NVPTX_DEBUG})
-    set(CUDA_DEBUG -DOMPTARGET_NVPTX_DEBUG=-1 -g --ptxas-options=-v)
-  endif()
-
-  # NVPTX runtime library has to be statically linked. Dynamic linking is not
-  # yet supported by the CUDA toolchain on the device.
-  set(BUILD_SHARED_LIBS OFF)
-  set(CUDA_SEPARABLE_COMPILATION ON)
-  list(APPEND CUDA_NVCC_FLAGS -I${devicertl_base_directory}
-                              -I${devicertl_nvptx_directory}/src)
-  cuda_add_library(omptarget-nvptx STATIC ${cuda_src_files} ${omp_data_objects}
-      OPTIONS ${CUDA_ARCH} ${CUDA_DEBUG} ${MAX_SM_DEFINITION})
-
-  # Install device RTL under the lib destination folder.
-  install(TARGETS omptarget-nvptx ARCHIVE DESTINATION "${OPENMP_INSTALL_LIBDIR}")
-
-  target_link_libraries(omptarget-nvptx ${CUDA_LIBRARIES})
-
 
   # Check if we can create an LLVM bitcode implementation of the runtime library
   # that could be inlined in the user application. For that we need to find
@@ -196,7 +177,7 @@
       # Copy library to destination.
       add_custom_command(TARGET omptarget-nvptx-${sm}-bc POST_BUILD
                          COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/libomptarget-nvptx-sm_${sm}.bc
-                         $<TARGET_FILE_DIR:omptarget-nvptx>)
+                         ${LIBOMPTARGET_LIBRARY_DIR})
 
       # Install bitcode library under the lib destination folder.
       install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libomptarget-nvptx-sm_${sm}.bc DESTINATION "${OPENMP_INSTALL_LIBDIR}")


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D94573.316297.patch
Type: text/x-patch
Size: 2622 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/openmp-commits/attachments/20210113/37116f93/attachment-0001.bin>