llvmbot
commented
3 months ago @llvm/issue-subscribers-openmp
Author: Martin Valgur (valgur)
When building OpenMP as a standalone with MSVC, `libomp.dll.lib` gets built as the import library, but CMake tries to install `libomp.lib` and fails.
OS: Windows 11
Compiler: Visual Studio 2022 / MSVC 19.38
CMake: both 3.21 and 3.29 fail
Configuration: x64 Release
Source version: openmp-18.1.3.src.tar.xz and cmake-18.1.3.src.tar.xz, but fails with v17 as well and older ones fail due to other reasons
Abbreviated build log (the full one can be seen here https://gist.github.com/valgur/cc65918157c6e9835492cb19ab160e6a):
```
$ cmake -B build src -G "Visual Studio 17 2022" -DCMAKE_TOOLCHAIN_FILE="build/generators/conan_toolchain.cmake" -DCMAKE_POLICY_DEFAULT_CMP0091=NEW
$ cmake --build build --config Release
MSBuild version 17.8.3+195e7f5a3 for .NET Framework
Generating libomp.def
Creating library build/runtime/src/Release/libomp.dll.lib and object build/runtime/src/Release/libomp.dll.exp
omp.vcxproj -> build\runtime\src\Release\libomp.dll
Generating libomp.imp.def
$ cmake --install build --config Release --prefix package
-- Installing: package/bin/libomp.dll
CMake Error at runtime/src/cmake_install.cmake:51 (file):
file INSTALL cannot find
"build/runtime/src/Release/libomp.lib":
File exists.
```
`cmake_toolchain.cmake`:
```cmake
set(BUILD_SHARED_LIBS ON)
set(OPENMP_STANDALONE_BUILD ON)
set(LIBOMP_ENABLE_SHARED ON)
set(LIBOMP_INSTALL_ALIASES OFF)
set(LIBOMP_OMPT_SUPPORT OFF)
set(OPENMP_ENABLE_LIBOMPTARGET OFF)
set(OPENMP_MSVC_NAME_SCHEME ON) # Fails with ON as well
```
Related to this PR on Conan Center Index: https://github.com/conan-io/conan-center-index/pull/22353
I wonder what I'm doing wrong since it seems unlikely for such a basic error to have persisted for so many versions? I did not find any similar issues or PRs either.
----
There are two potential fixes that I can suggest.
1. Keep the `.dll.lib` suffix and fix the installed file name:
https://github.com/llvm/llvm-project/blob/llvmorg-18.1.3/openmp/runtime/src/CMakeLists.txt#L306
```patch
--- openmp/runtime/src/CMakeLists.txt
+++ openmp/runtime/src/CMakeLists.txt
@@ -315,7 +315,7 @@
# making it a .txt which CMAKE will filter out from the librarian (a .cpp will make lib.exe punt trying to resolve the .def symbols)
add_library(${LIBOMP_IMP_LIB_TARGET} STATIC kmp_dummy.txt)
set_target_properties(${LIBOMP_IMP_LIB_TARGET} PROPERTIES
- PREFIX "" SUFFIX "" OUTPUT_NAME "${LIBOMP_IMP_LIB_FILE}" LINKER_LANGUAGE ${LIBOMP_LINKER_LANGUAGE}
+ PREFIX "" SUFFIX "" OUTPUT_NAME "${LIBOMP_GENERATED_IMP_LIB_FILENAME}" LINKER_LANGUAGE ${LIBOMP_LINKER_LANGUAGE}
STATIC_LIBRARY_OPTIONS "${CMAKE_LINK_DEF_FILE_FLAG}${CMAKE_CURRENT_BINARY_DIR}/${LIBOMPIMP_GENERATED_DEF_FILE}")
add_dependencies(${LIBOMP_IMP_LIB_TARGET} libompimp-needed-def-file)
add_dependencies(omp ${LIBOMP_IMP_LIB_TARGET})
```
2. Change the suffix to `.lib` to match the installed file name:
https://github.com/llvm/llvm-project/blob/llvmorg-18.1.3/openmp/runtime/src/CMakeLists.txt#L267
```patch
--- openmp/runtime/src/CMakeLists.txt
+++ openmp/runtime/src/CMakeLists.txt
@@ -276,7 +276,7 @@
endif()
else()
set(LIBOMP_IMP_LIB_FILE ${LIBOMP_LIB_NAME}${CMAKE_IMPORT_LIBRARY_SUFFIX})
- set(LIBOMP_GENERATED_IMP_LIB_FILENAME ${LIBOMP_LIB_FILE}${CMAKE_STATIC_LIBRARY_SUFFIX})
+ set(LIBOMP_GENERATED_IMP_LIB_FILENAME ${LIBOMP_LIB_NAME}${CMAKE_STATIC_LIBRARY_SUFFIX})
endif()
set_target_properties(omp PROPERTIES
VERSION ${LIBOMP_VERSION_MAJOR}.${LIBOMP_VERSION_MINOR} # uses /version flag
```
When building OpenMP as a standalone with MSVC,
libomp.dll.libgets built as the import library, but CMake tries to installlibomp.liband fails.OS: Windows 11 Compiler: Visual Studio 2022 / MSVC 19.38 CMake: both 3.21 and 3.29 fail Configuration: x64 Release Source version: openmp-18.1.3.src.tar.xz and cmake-18.1.3.src.tar.xz, but fails with v17 as well and older ones fail due to other reasons
Abbreviated build log (the full one can be seen here https://gist.github.com/valgur/cc65918157c6e9835492cb19ab160e6a):
cmake_toolchain.cmake:Related to this PR on Conan Center Index: https://github.com/conan-io/conan-center-index/pull/22353
I wonder what I'm doing wrong since it seems unlikely for such a basic error to have persisted for so many versions? I did not find any similar issues or PRs either.
There are two potential fixes that I can suggest.
.dll.libsuffix and fix the installed file name: https://github.com/llvm/llvm-project/blob/llvmorg-18.1.3/openmp/runtime/src/CMakeLists.txt#L306.libto match the installed file name: https://github.com/llvm/llvm-project/blob/llvmorg-18.1.3/openmp/runtime/src/CMakeLists.txt#L267