llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-driver Author: Joseph Huber (jhuber6) <details> <summary>Changes</summary> Summary: Currently, we build a single `libomptarget.devicertl.a` which is a fatbinary. It is a host object file that contains the embedded archive files for both the NVIDIA and AMDGPU targets. This was done primarily as a convenience due to naming conflicts. Now that the clang driver for the GPU targets can appropriate link via the per-target runtime-dir, we can just make two separate static libraries and remove the indirection. This patch creates two new static libraries that get installed into ``` /lib/amdgcn-amd-amdhsa/libomp.a /lib/nvptx64-nvidia-cuda/libomp.a ``` for AMDGPU and NVPTX respectively. The link job created by the linker wrapper now simply needs to do `-lomp` and it will search those directories and link those static libraries. This requires far less special handling. This patch is a precursor to changing the build system entirely to be a runtimes based one. Soon this target will be a standard `add_library` and done through the GPU runtime targets. NOTE that this actually does remove an additional optimization step. Previously we merged all of the files into a single bitcode object and forcibly internalized some definitions. This, instead, just treats them like a normal static library. This may possibly affect performance for some files, but I think it's better overall to use static library semantics because it allows us to have an 'include-what-you-use' relationship with the library. Performance testing will be required. If we really need the merged blob then we can simply pack that into a new static library. --- Full diff: https://github.com/llvm/llvm-project/pull/126143.diff 4 Files Affected: - (modified) clang/lib/Driver/ToolChains/Clang.cpp (+4) - (modified) clang/lib/Driver/ToolChains/CommonArgs.cpp (-3) - (modified) offload/DeviceRTL/CMakeLists.txt (+30-103) - (modified) offload/test/lit.cfg (+4-4) ``````````diff diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index c0891d46b0a62cd..fd690ab11c1c2c3 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -9209,6 +9209,10 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA, A->render(Args, LinkerArgs); } + // If this is OpenMP the device linker will need `-lomp`. + if (Kind == Action::OFK_OpenMP && !Args.hasArg(OPT_nogpulib)) + LinkerArgs.emplace_back("-lomp"); + // Forward all of these to the appropriate toolchain. for (StringRef Arg : CompilerArgs) CmdArgs.push_back(Args.MakeArgString( diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp index 699aadec86dcba9..93031d2f5302386 100644 --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp @@ -1289,9 +1289,6 @@ bool tools::addOpenMPRuntime(const Compilation &C, ArgStringList &CmdArgs, if (IsOffloadingHost) CmdArgs.push_back("-lomptarget"); - if (IsOffloadingHost && !Args.hasArg(options::OPT_nogpulib)) - CmdArgs.push_back("-lomptarget.devicertl"); - addArchSpecificRPath(TC, Args, CmdArgs); addOpenMPRuntimeLibraryPath(TC, Args, CmdArgs); diff --git a/offload/DeviceRTL/CMakeLists.txt b/offload/DeviceRTL/CMakeLists.txt index 8f2a1fd01fabcc8..b3dd4a1997d80d0 100644 --- a/offload/DeviceRTL/CMakeLists.txt +++ b/offload/DeviceRTL/CMakeLists.txt @@ -107,15 +107,15 @@ set(bc_flags -c -flto -std=c++17 -fvisibility=hidden ) # first create an object target -add_library(omptarget.devicertl.all_objs OBJECT IMPORTED) function(compileDeviceRTLLibrary target_name target_triple) set(target_bc_flags ${ARGN}) set(bc_files "") + add_library(omp.${target_name}.all_objs OBJECT IMPORTED) foreach(src ${src_files}) get_filename_component(infile ${src} ABSOLUTE) get_filename_component(outfile ${src} NAME) - set(outfile "${outfile}-${target_name}.bc") + set(outfile "${outfile}-${target_name}.o") set(depfile "${outfile}.d") # Passing an empty CPU to -march= suppressed target specific metadata. @@ -142,99 +142,36 @@ function(compileDeviceRTLLibrary target_name target_triple) endif() set_property(DIRECTORY APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES ${outfile}) - list(APPEND bc_files ${outfile}) + list(APPEND obj_files ${CMAKE_CURRENT_BINARY_DIR}/${outfile}) endforeach() - - set(bclib_name "libomptarget-${target_name}.bc") - - # Link to a bitcode library. - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/linked_${bclib_name} - COMMAND ${LINK_TOOL} - -o ${CMAKE_CURRENT_BINARY_DIR}/linked_${bclib_name} ${bc_files} - DEPENDS ${bc_files} - COMMENT "Linking LLVM bitcode ${bclib_name}" - ) - - if(TARGET llvm-link) - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/linked_${bclib_name} - DEPENDS llvm-link - APPEND) - endif() - - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/internalized_${bclib_name} - COMMAND ${OPT_TOOL} ${link_export_flag} ${CMAKE_CURRENT_BINARY_DIR}/linked_${bclib_name} - -o ${CMAKE_CURRENT_BINARY_DIR}/internalized_${bclib_name} - DEPENDS ${source_directory}/exports ${CMAKE_CURRENT_BINARY_DIR}/linked_${bclib_name} - COMMENT "Internalizing LLVM bitcode ${bclib_name}" - ) - if(TARGET opt) - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/internalized_${bclib_name} - DEPENDS opt - APPEND) - endif() - - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name} - COMMAND ${OPT_TOOL} ${link_opt_flags} ${CMAKE_CURRENT_BINARY_DIR}/internalized_${bclib_name} - -o ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name} - DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/internalized_${bclib_name} - COMMENT "Optimizing LLVM bitcode ${bclib_name}" - ) - if(TARGET opt) - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name} - DEPENDS opt - APPEND) - endif() - - set(bclib_target_name "omptarget-${target_name}-bc") - add_custom_target(${bclib_target_name} DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name}) - - # Copy library to destination. - add_custom_command(TARGET ${bclib_target_name} POST_BUILD - COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name} - ${LIBOMPTARGET_LIBRARY_DIR}) - add_dependencies(omptarget.devicertl.${target_name} ${bclib_target_name}) - - set_property(DIRECTORY APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES ${bclib_name} ${LIBOMPTARGET_LIBRARY_DIR}/${bclib_name}) - - # Install bitcode library under the lib destination folder. - install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name} DESTINATION "${OFFLOAD_INSTALL_LIBDIR}") - - set(target_feature "") - if("${target_triple}" STREQUAL "nvptx64-nvidia-cuda") - set(target_feature "feature=+ptx63") - endif() - - # Package the bitcode in the bitcode and embed it in an ELF for the static library - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/packaged_${bclib_name} - COMMAND ${PACKAGER_TOOL} -o ${CMAKE_CURRENT_BINARY_DIR}/packaged_${bclib_name} - "--image=file=${CMAKE_CURRENT_BINARY_DIR}/${bclib_name},${target_feature},triple=${target_triple},arch=generic,kind=openmp" - DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${bclib_name} - COMMENT "Packaging LLVM offloading binary ${bclib_name}.out" + set_property(TARGET omp.${target_name}.all_objs + APPEND PROPERTY IMPORTED_OBJECTS ${obj_files}) + + # Archive all the object files generated above into a static library + add_library(omp.${target_name} STATIC) + set_target_properties(omp.${target_name} PROPERTIES + ARCHIVE_OUTPUT_DIRECTORY "${LIBOMPTARGET_LLVM_LIBRARY_INTDIR}/${target_triple}" + ARCHIVE_OUTPUT_NAME omp + LINKER_LANGUAGE CXX ) - if(TARGET clang-offload-packager) - add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/packaged_${bclib_name} - DEPENDS clang-offload-packager - APPEND) - endif() - - set(output_name "${CMAKE_CURRENT_BINARY_DIR}/devicertl-${target_name}.o") - add_custom_command(OUTPUT ${output_name} - COMMAND ${CLANG_TOOL} --std=c++17 -c -nostdlib - -Xclang -fembed-offload-object=${CMAKE_CURRENT_BINARY_DIR}/packaged_${bclib_name} - -o ${output_name} - ${source_directory}/Stub.cpp - DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/packaged_${bclib_name} ${source_directory}/Stub.cpp - COMMENT "Embedding LLVM offloading binary in devicertl-${target_name}.o" - VERBATIM - ) - if(TARGET clang) - add_custom_command(OUTPUT ${output_name} - DEPENDS clang - APPEND) - endif() - - set_property(DIRECTORY APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES ${output_name}) - set_property(TARGET omptarget.devicertl.all_objs APPEND PROPERTY IMPORTED_OBJECTS ${output_name}) + target_link_libraries(omp.${target_name} PRIVATE omp.${target_name}.all_objs) + + install(TARGETS omp.${target_name} + ARCHIVE DESTINATION "lib${LLVM_LIBDIR_SUFFIX}/${target_triple}") + + # Trick to combine these into a bitcode file via the linker's LTO pass. This + # is used to provide the legacy `libomptarget-<name>.bc` files. + add_executable(libomptarget-${target_name} ${obj_files}) + set_target_properties(libomptarget-${target_name} PROPERTIES + RUNTIME_OUTPUT_DIRECTORY ${LIBOMPTARGET_LLVM_LIBRARY_INTDIR} + LINKER_LANGUAGE CXX + RUNTIME_OUTPUT_NAME libomptarget-${target_name}.bc) + target_compile_options(libomptarget-${target_name} PRIVATE "--target=${target_triple}") + target_link_options(libomptarget-${target_name} PRIVATE "--target=${target_triple}" + "-r" "-nostdlib" "-flto" "-Wl,--lto-emit-llvm") + install(TARGETS libomptarget-${target_name} + PERMISSIONS OWNER_WRITE OWNER_READ GROUP_READ WORLD_READ + DESTINATION ${OFFLOAD_INSTALL_LIBDIR}) if (CMAKE_EXPORT_COMPILE_COMMANDS) set(ide_target_name omptarget-ide-${target_name}) @@ -259,13 +196,3 @@ compileDeviceRTLLibrary(amdgpu amdgcn-amd-amdhsa -Xclang -mcode-object-version=n add_custom_target(omptarget.devicertl.nvptx) compileDeviceRTLLibrary(nvptx nvptx64-nvidia-cuda --cuda-feature=+ptx63) - -# Archive all the object files generated above into a static library -add_library(omptarget.devicertl STATIC) -set_target_properties(omptarget.devicertl PROPERTIES - ARCHIVE_OUTPUT_DIRECTORY "${LIBOMPTARGET_LLVM_LIBRARY_INTDIR}" - LINKER_LANGUAGE CXX -) -target_link_libraries(omptarget.devicertl PRIVATE omptarget.devicertl.all_objs) - -install(TARGETS omptarget.devicertl ARCHIVE DESTINATION ${OFFLOAD_INSTALL_LIBDIR}) diff --git a/offload/test/lit.cfg b/offload/test/lit.cfg index 658ae5f9653ba90..565edc3e7faeb9d 100644 --- a/offload/test/lit.cfg +++ b/offload/test/lit.cfg @@ -183,11 +183,11 @@ def remove_suffix_if_present(name): def add_libraries(source): if config.libomptarget_has_libc: - return source + " -Xoffload-linker " + "-lc " + \ - "-Xoffload-linker " + "-lm " + \ - config.llvm_library_intdir + "/libomptarget.devicertl.a" + return source + " -Xoffload-linker -lc " + \ + "-Xoffload-linker -lm " + \ + "-Xoffload-linker -lomp " else: - return source + " " + config.llvm_library_intdir + "/libomptarget.devicertl.a" + return source + " " + "-Xoffload-lnker -lomp" # Add platform targets host_targets = [ `````````` </details> https://github.com/llvm/llvm-project/pull/126143 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
