2f5771c8ec
Fixes #211135. `openmp/module/CMakeLists.txt:29` gates the GPU-only Fortran compile options on `"^amdgcn|^nvptx"`, while `openmp/CMakeLists.txt:176-177` selects host-vs-device layout for the same build using `"^amdgpu|^amdgcn|^nvptx|^spirv64"` against both `LLVM_DEFAULT_TARGET_TRIPLE` and `CMAKE_CXX_COMPILER_TARGET`. All four offload cache files use the triple `amdgpu-amd-amdhsa`, which `^amdgcn` does not match, so `-nogpulib -flto` are silently not applied to `libomp-mod` in the recommended AMDGPU offload configurations. Compute the test once as `LIBOMP_TARGET_IS_GPU` in `openmp/CMakeLists.txt` and use it at both sites, rather than duplicating a widened regex. The conditions differ, not just the patterns: copying the regex alone would leave a build that sets `CMAKE_CXX_COMPILER_TARGET` without `LLVM_DEFAULT_TARGET_TRIPLE` still taking the device path in `openmp/` while `libomp-mod` misses the flags. `libomp-mod` compiles Fortran, so `CMAKE_Fortran_COMPILER_TARGET` is also consulted; neither site did before. Evaluated with CMake's regex engine: | triple | before | after | |---|---|---| | `amdgpu-amd-amdhsa` | 0 | 1 | | `amdgcn-amd-amdhsa` | 1 | 1 | | `nvptx64-nvidia-cuda` | 1 | 1 | | `spirv64-amd-amdhsa` | 0 | 1 | | `x86_64-unknown-linux-gnu` | 0 | 0 | `^spirv64` only brings `module/` in line with `openmp/CMakeLists.txt:176`, which already routes spirv64 to `device/`. Host builds are unaffected. Roughly five other sites carry the same `amdgcn`-only pattern (`offload/CMakeLists.txt:30`, `flang-rt/CMakeLists.txt:126`, `flang-rt/lib/runtime/CMakeLists.txt:317`, `flang-rt/cmake/modules/AddFlangRT.cmake:298`, `cmake/Modules/GetToolchainDirs.cmake:118`) and are left for a follow-up. No test: configure-time logic, no test mechanism exists in `openmp/`. This affects performance-critical applications on large AMD GPU supercomputers, including [MFC](https://github.com/MFlowCode/MFC). All numbers above come from the validated reproducers included with this report and are independently reproducible; they stand on their own. This was found and root-caused with the assistance of AI tools.
53 lines
2 KiB
CMake
53 lines
2 KiB
CMake
#//===----------------------------------------------------------------------===//
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#//
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#// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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#// See https://llvm.org/LICENSE.txt for license information.
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#// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#//
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#//===----------------------------------------------------------------------===//
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# Build the module files if a Fortran compiler is available.
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configure_file(omp_lib.F90.var "${CMAKE_CURRENT_BINARY_DIR}/omp_lib.F90" @ONLY)
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configure_file(omp_lib.h.var "${RUNTIMES_OUTPUT_RESOURCE_MOD_DIR}/omp_lib.h" @ONLY)
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# One compilation step creates both, omp_lib.mod and omp_lib_kinds.mod. Only
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# these files are used, the object file itself can be discarded.
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# TODO: Adding it to libomp ($<TARGET_OBJECTS:libomp-mod>) would allow implementing Fortran API in Fortran
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add_library(libomp-mod OBJECT
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"${CMAKE_CURRENT_BINARY_DIR}/omp_lib.F90"
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)
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set_target_properties(libomp-mod PROPERTIES FOLDER "OpenMP/Fortran Modules")
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# The following requests explicit building of the Fortran module files
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# Workaround for gfortran to build modules with the
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# omp_sched_monotonic integer parameter
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if (CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
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target_compile_options(libomp-mod PRIVATE -fno-range-check)
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endif ()
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if (LIBOMP_TARGET_IS_GPU)
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target_compile_options(libomp-mod PRIVATE
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$<$<COMPILE_LANGUAGE:Fortran>:-nogpulib -flto>
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)
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endif ()
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flang_module_target(libomp-mod PUBLIC)
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install(FILES
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"${RUNTIMES_OUTPUT_RESOURCE_MOD_DIR}/omp_lib.h"
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DESTINATION "${RUNTIMES_INSTALL_RESOURCE_MOD_PATH}"
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COMPONENT libomp-mod
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EXCLUDE_FROM_ALL
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)
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if (NOT CMAKE_CONFIGURATION_TYPES)
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add_custom_target(install-libomp-mod
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DEPENDS libomp-mod
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COMMAND "${CMAKE_COMMAND}" --install "${CMAKE_BINARY_DIR}"
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--component libomp-mod)
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add_custom_target(install-libomp-mod-stripped
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DEPENDS libomp-mod
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COMMAND "${CMAKE_COMMAND}" --install "${CMAKE_BINARY_DIR}"
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--component libomp-mod --strip)
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endif ()
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