Bytecode build failure

[code-ghalib]

I'm trying to build an empty dune project depending on owl, created using dune init proj test --libs owl, and I get this error:

$ dune build
Info: Creating file dune-project with this contents:
| (lang dune 2.7)
| (name test)
File "_none_", line 1:
Error: Error on dynamically loaded library: /home/me/.opam/4.11.1/lib/stublibs/dlleigen_cpp_stubs.so: /home/me/.opam/4.11.1/lib/stublibs/dlleigen_cpp_stubs.so: undefined symbol: _ZTVN10__cxxabiv117__class_type_infoE
Done: 37/41 (jobs: 1)

My system information is:

$ uname -srvimo
Linux 5.8.18-1-MANJARO #1 SMP PREEMPT Sun Nov 1 14:10:04 UTC 2020 x86_64 unknown GNU/Linux

Additionally, CC, CXX, LD_LIBRARY_PATH are all unset in my environment.
ldd shows this:

$ ldd /home/me/.opam/4.11.1/lib/stublibs/dlleigen_cpp_stubs.so
	linux-vdso.so.1 (0x00007ffea1dc6000)
	libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f63b0c21000)
	libc.so.6 => /usr/lib/libc.so.6 (0x00007f63b0a58000)
	/usr/lib64/ld-linux-x86-64.so.2 (0x00007f63b0ed2000)

Looks like libstdc++ is not there which seems surprising considering these are cpp stubs. Am I doing something wrong? Read some of the other issues that seemed related - is there a workaround short of attempting to build from source? I'm also not sure how to build from source and have it replaced inside the opam directory (not a heavy opam user). There doesn't seem to be a dockerfile for arch-linux here - is this platform not supported? Any help would be appreciated - thanks.

[code-ghalib]

Update: the problem is only with bytecode build, updating dune rules to only build native mode works.
e.g.

(test
 (name test)
 (libraries owl)
 (modes native))

Not sure if it is a platform-specific issue.

[kkirstein]

I get the same error when installing owl-zoo (on Ubuntu 20.04). It looks like -lstdc++ has been (accidentely?) removed for dlleigen_cpp_stubs (commit) and (re-)added for eigen lib itself (commit). I think it should be the other way around, as it was before.

[ryanrhymes]

#24 @mseri @kkirstein

[mseri]

foreign_library does not support c_library_flags, that has to go in the library using the stubs. Looks like we have two issues which are mutually breaking with things as they are now.

@nojb do you know if there is an alternative way for the fix from #27? I am pinging also the relative dune thread: ocaml/dune#3908

[nojb]

Did you try adding a (flags -lstdc++) field to the foreign_library stanza? If it works, I think you could remove the (c_library_flags ...) field.

[mseri]

I am doing that locally in a branch, seems to work but still testing. But then I am quite confused by the difference between the compiler/preprocessor flags and the link flags

[kkirstein]

@ryanrhymes @mseri thanks for your hints. That explains the „movement“ of linking flags. I will also test the fix on Windows when merged.

[nojb]

For info, in the future dune will do the right thing with respect to -lstdc++ it won't be necessary to add it explicitly. But the PR has not yet been merged ocaml/dune#3802. It should happen soon, though.

[mseri]

Thanks!

[mseri]

I am going to keep this open until we move to a dune with the new feature.
@kkirstein @nilsbecker can you check if the master branch of eigen works for you? If so, I am going to make a new release