Don't use floating-point environment methods from openlibm.

[maleadt]

Fixes #38427, see JuliaMath/openlibm#219

[maleadt]

Kicked-off a build with USE_BINARYBUILDER_OPENLIBM=false DEPS_GIT=openlibm here: https://build.julialang.org/#/builders/47/builds/1

[maleadt]

Fails to build on Windows because we don't seem to have floating-point functions there. Presumable this used to work, https://github.com/JuliaLang/julia/pull/36588/files#diff-b93461e172b1a09513b591004c100b10a2a3fcf407d51fc19e6be1cb73c246d4, because we were linking openlibm before.

@vtjnash You mentioned, #38427 (comment), we should have functions like fenv available on Windows, however ccall(:fegetenv, Cint, (Ptr{Cvoid},), C_NULL) (and the build here) fails. Do you have any insights?

Checking the libraries that are part of x86_64-w64-mingw32, listing only the ones that have something fesetenv-like:

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libmingwex.a
lib64_libmingwex_a-fesetenv.o:
0000000000000000 T fesetenv
                 U fesetenv

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libmsvcr120.a
0000000000000000 I __imp_fesetenv
0000000000000000 T fesetenv

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libmsvcr120_app.a
0000000000000000 I __imp_fesetenv
0000000000000000 T fesetenv

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libmsvcr120d.a
0000000000000000 I __imp_fesetenv
0000000000000000 T fesetenv

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libucrt.a
0000000000000000 I __imp_fesetenv

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libucrtapp.a
0000000000000000 I __imp_fesetenv

/usr/x86_64-w64-mingw32/sys-root/mingw/lib/libucrtbase.a
0000000000000000 I __imp_fesetenv

[vtjnash]

It looks like a .a library, so you need to force link it.

[maleadt]

I guess these functions are only in the ucrt, and not the msvcrt.dll we're using:

julia> crt = Libdl.dlopen("msvcrt.dll")
Ptr{Nothing} @0x00007ffbb0920000

julia> Libdl.dlsym(crt, "ferror")
Ptr{Nothing} @0x00007ffbb096cad0

julia> Libdl.dlsym(crt, "fegetenv")
ERROR: could not load symbol "fegetenv":
The specified procedure could not be found.

julia> crt = Libdl.dlopen("ucrtbase.dll")
Ptr{Nothing} @0x00007ffbaee70000

julia> Libdl.dlsym(crt, "fegetenv")
Ptr{Nothing} @0x00007ffbaee768d0

Switching to the ucrt seems quite an large change. Alternatively, we could ship libmingwex and use that?

[maleadt]

It looks like a .a library, so you need to force link it.

No, that results in lots of multiple definition errors. Looks like mingwex gets automatically linked already, presumably for C99 support when using msvcrt. So I'm trying to get it to export the fegetround/fesetround defs from that static library, is there a clean way to do that other than introducing a 'fake' use somewhere in julia or libjulia?

Also, any thoughts about this:

Tim@DESKTOP-1NUTSID ~/julia
$ nm -g usr/bin/libjulia.dll | grep feget
0000000065471370 T fegetround

Tim@DESKTOP-1NUTSID ~/julia
$ ./julia.bat -q
julia> using Libdl

julia> lib = Libdl.dlopen("usr/bin/libjulia.dll")
Ptr{Nothing} @0x00000000028f0000

julia> Libdl.dlsym(lib, "fegetround")
ERROR: could not load symbol "fegetround":
The specified procedure could not be found.

[vtjnash]

--require-defined=fesetround

Though to re-export it, I think you may need to mark it during the build, as exported symbols have a different name mangling

[maleadt]

Thanks, I'll try that. Alternatively, we do an if Sys.iswindows() for these calls and have them use openlibm there, but that would require some reordering of the bootstrap includes.

[maleadt]

Couldn't get it to work; nm and objdump were lying to/confusing me as the symbols weren't visible in Dependencies.
Anyway, decided to take the simpler option of introducing jl_fegetround/jl_fesetround.
Kicked off another build to use openlibm from master here: https://build.julialang.org/#/builders/47/builds/2

[vtjnash]

Could also just add another special case to the jitlayers file. I know we already have a few there.

[maleadt]

Could also just add another special case to the jitlayers file.

Ah, yes. This seems like a simpler solution though, and does the job as well.

CI failures unrelated (happen on master too), and the manual build using openlibm#master, https://build.julialang.org/#/buildersj/47/builds/2, successfully builds and tests on all platforms too. Let's generate new binaries now.

[nico202]

I'm trying to build julia#110f1256ac with openlibm 0.7.3 and it's failing with

LoadError("sysimg.jl", 3, LoadErjuliaor("Base.jl", 269, LoadError("floatfuncs.jl", 345, ErrorException("could not load symbol \"fesetround\":\n/tmp/guix-build-julia-1.5.3-git.drv-0/source/usr/bin/../lib/libopenlibm.so: undefined symbol: fesetround"))))

Is this related?
Thanks

[maleadt]

Yes, how come you are using openlibm 0.7.3 already? It needs this PR.

@staticfloat Looks like the x86_64-apple-darwin build has dropped its '14' tag. What do I need to change here, or in Yggdrasil?
EDIT: I renamed the asset 🙈

[nico202]

I'm preparing the next package for guix, just saw the new tagged openlibm release and updated it (we use USE_SYSTEM_OPENLIBM=1).
I'll try with 0.7.2 in the meanwhile, thanks

[maleadt]

Should be good to go now.