Building with VS2017 fails

[joa-quim]

First error was that it insisted in requiring gfortran so I tricked it my making a symlink with flang.exe.
Next error, which I could not solve is this:

(C:\programs\Miniconda3) V:\openblas\build>cmake --build . --config Release
ninja: error: 'openblas.def', needed by 'lib/liblibopenblas.dll', missing and no known rule to make it

apparently openblas.def should have been generated in previous step, but it wasn't

[isuruf]

Are you using latest master of OpenBLAS? What is the cmake generator and the options you used?

[joa-quim]

Yes, 0.2.20 and I'm following the instructions of point 1 of

https://github.com/xianyi/OpenBLAS/wiki/How-to-use-OpenBLAS-in-Microsoft-Visual-Studio

[isuruf]

You need to use openblas git version for that.

[joa-quim]

Well, then perhaps change the entry sentence.

As of OpenBLAS v0.2.15, we support MinGW and Visual Studio (using CMake to generate visual studio solution files) to build OpenBLAS on Windows.

[joa-quim]

Hmm, not better

-- The Fortran compiler identification is unknown
flang.exe: warning: argument unused during compilation: '-E' [-Wunused-command-line-argument]
flang.exe: error: linker command failed with exit code 1120 (use -v to see invocation)
-- Check for working Fortran compiler: C:/programs/Miniconda3/Library/bin/flang.exe
CMake Error: Error required internal CMake variable not set, cmake may not be built correctly.
Missing variable is:
CMAKE_Fortran_PREPROCESS_SOURCE
CMake Error at C:/programs/CMake/share/cmake-3.8/Modules/CMakeTestFortranCompiler.cmake:30 (try_compile):
  Failed to generate test project build system.
Call Stack (most recent call first):
  cmake/f_check.cmake:24 (enable_language)
  cmake/prebuild.cmake:84 (include)
  cmake/system.cmake:118 (include)
  CMakeLists.txt:44 (include)

[brada4]

flang detection is only with development version

[joa-quim]

This was with development version.

[martin-frbg]

Your version of CMAKE is too old to recognize flang - it seems that the relevant definitions were added to cmake in August as https://gitlab.kitware.com/cmake/cmake/commit/2f3a07a9 so you would need at least CMAKE 3.10.0

[isuruf]

Actually for recognizing flang on windows, you need the development version of cmake. (Or use the cmake from conda)

[joa-quim]

Thanks, updated cmake and advanced quite a bit ... but it stops with hundreds of errors like

flang.exe: error: no such file or directory: 'CMakeFileslibopenblas.dirlapack-netlibLAPACKEutilslapacke_z_nancheck.c.obj'
flang.exe: error: no such file or directory: 'CMakeFileslibopenblas.dirlapack-netlibLAPACKEutilslapacke_ztr_trans.c.obj'
flang.exe: error: no input files
ninja: build stopped: subcommand failed.

A missing slash separator apparently because, for example, the lapacke_ztr_trans.c.obj file exists in

V:\openblas\build\CMakeFiles\libopenblas.dir\lapack-netlib\LAPACKE\utils

[joa-quim]

One more try. I hand edited the build.ninja file and changed all \ by / and the above errors went way, but now

[2/3] Linking Fortran shared library lib/libopenblas.dll
FAILED: lib/libopenblas.dll lib/libopenblas.lib
cmd.exe /C "cd . && C:\programs\Miniconda3\Library\bin\flang.exe  -Wall  /machine:x64 /debug /INCREMENTAL /DEF:V:/openblas/build/openblas.def  /DEF:openblas.def -shared  -o lib/libopenblas.dll @CMakeFiles/libopenblas.rsp  && cd ."
flang.exe: error: no such file or directory: '/machine:x64'
flang.exe: error: no such file or directory: '/debug'
flang.exe: error: no such file or directory: '/INCREMENTAL'
flang.exe: error: no such file or directory: '/DEF:V:/openblas/build/openblas.def'
flang.exe: error: no such file or directory: '/DEF:openblas.def'
ninja: build stopped: subcommand failed.

[isuruf]

Did you clean the build directory after changing cmake version?

[joa-quim]

No, I hadn't but it makes no difference. Same errors.

[joa-quim]

Sorry, cleaned the build dir of another project. Redoing it now.

[joa-quim]

but again, no difference. Still errors.

[vakonovalov]

I was able to build OpenBLAS (recent commit c7b55b6 from develop branch) on Windows. I used VS2015, i don't know if it would work with VS2017.
The problem with CMAKE_Fortran_PREPROCESS_SOURCE is indeed solved by installing a new version of CMake. I used 3.10.2.

Then, however, there were errors with linking:

[2/3] Linking Fortran shared library lib\openblas.dll
FAILED: lib/openblas.dll lib/Release/openblas.lib
cmd.exe /C "cd . && <PATH_TO_CONDA>\Library\bin\flang.exe    /machine:x64 /INCREMENTAL:NO /DEBUG /OPT:REF /OPT:ICF /DEF:<PATH_TO_OPENBLAS>\OpenBLAS-develop\build\openblas.def  /DEF:openblas.def -shared  -o lib\openblas.dll @CMakeFiles/openblas.rsp  && cd ."
ninja: build stopped: subcommand failed.

Using build.ninja i determined that Fortran_SHARED_LIBRARY_LINKER__openblas is responsible for incorrect formation of this command.
In rules.ninja i changed

rule Fortran_SHARED_LIBRARY_LINKER__openblas
  command = cmd.exe /C "$PRE_LINK && <PATH_TO_CONDA>\Library\bin\flang.exe  $LANGUAGE_COMPILE_FLAGS $ARCH_FLAGS $LINK_FLAGS -shared $SONAME_FLAG$SONAME -o $TARGET_FILE @$RSP_FILE  && $POST_BUILD"

to

rule Fortran_SHARED_LIBRARY_LINKER__openblas
  command = cmd.exe /C "$PRE_LINK && link  $LANGUAGE_COMPILE_FLAGS $ARCH_FLAGS $LINK_FLAGS /DLL /OUT:$TARGET_FILE @$RSP_FILE  && $POST_BUILD"

But that was not all. There was another small bug:

[3/3] Linking C executable utest\openblas_utest.exe
FAILED: utest/openblas_utest.exe
.....
LINK : fatal error LNK1181: cannot open input file "lib\Release\openblas.lib"
ninja: build stopped: subcommand failed.

This problem was solved by manually copying openblas.lib from lib to lib\Release
After these fixes, the build was finally completed.

[isuruf]

@vakonovalov, can you remove your changes and try with cmake-3.11.0 and see if it succeeds or not?

[vakonovalov]

I tried to build OpenBLAS using CMake 3.11.0. The build was successful, there was no need for my intervention in the process.

I noticed that the rule Fortran_SHARED_LIBRARY_LINKER__openblas have changed to

rule Fortran_SHARED_LIBRARY_LINKER__openblas
  command = cmd.exe /C "$PRE_LINK && D:\Programs\CMake\bin\cmake.exe -E vs_link_dll --intdir=$OBJECT_DIR --manifests $MANIFESTS -- D:\Programs\MICROS~1.0\VC\bin\amd64\link.exe /nologo @$RSP_FILE  /out:$TARGET_FILE /implib:$TARGET_IMPLIB /pdb:$TARGET_PDB /dll /version:0.3 $LINK_FLAGS   && $POST_BUILD"

Now it works correctly. Also, there was no need to manually copy openblas.lib from lib to lib\Release.

So, with CMake 3.11.0 it seems that everything works fine.

[martin-frbg]

According to #1521, building with VS2017 should work as well with current conda/cmake/ninja/flang