OSX: Compiling a shared library with `rdmd` points to `name.dylib.tmp` instead of `name.dylib`

[dlang-bugzilla-migration]

Transferred from: https://issues.dlang.org/show_bug.cgi?id=17216

User @timotheecour reported (2017-Feb-21 05:06:39):

v2.072.2 rdmd build 20170108

fun.d:whatever

rdmd -v --force --build-only -shared -oflibfun.dylib fun.d

creates libfun.dylib

otool -L libfun.dylib
libfun.dylib:
        libfun.dylib.tmp (compatibility version 0.0.0, current version 0.0.0)

libfun.dylib.tmp is wrong, and will cause errors when linking via -lfun, eg: dyld: Library not loaded: libfun.dylib.tmp

This used to work on OSX (and works on linux)

User @timotheecour responded (2017-Feb-21 05:17:26):

same with latest: DMD64 D Compiler v2.073.1 rdmd build 20170220

User @timotheecour responded (2017-Feb-21 05:33:14):

workaround: -L-install_name -Llibfun.dylib

User @cqexbesd responded (2017-May-07 13:44:23):

This is still occurring in HEAD.

When rdmd calls dmd it gives an output name that ends with ".tmp" (https://github.com/dlang/tools/blob/master/rdmd.d#L483-L488) and that is what dmd passes to clang (used for linking under OSX). As the install_name arg isn't given thats what ends up being the install_name of the dylib and hence this problem.

There are two obvious ways of fixing it - get dmd to call clang with install_name or run install_name_tool after building.

Neither seem obviously great - IIUC rdmd doesn't know its building a shared library so doesn't know install_name is important. dmd does know but isn't aware that rdmd has passed it a dummy output name that will later get mv'ed to the final name.

I don't yet know if rdmd needs to use the .tmp then mv trick but I'm guessing its there to cope with some sort of error on some platform - if that could be avoided the problem would disappear. Anything else seems to require rdmd learning about shared libraries under OSX or dmd having more awareness of rdmd.

User @cqexbesd responded (2017-May-07 13:49:35):

OK .tmp is added at https://github.com/dlang/tools/commit/085dc5d000b828be9a3c2dc79548352f63b52db4 to work around a Windows problem so removing it without an alternative wouldn't be good.

User @cqexbesd responded (2017-May-07 14:29:52):

I now have a fix at https://github.com/cqexbesd/tools/tree/dlang_17216.

It's not great - it just makes the windows work around only happen under Windows.

Given https://github.com/cqexbesd/tools/blob/d27bcc1228863ba0a3b0ae5cf47a8d3a409bda45/rdmd.d#L461-L481 however I'm not sure that the windows workaround should still be needed. The rm code didn't exist when the workaround was added AFAIK. I might try removing the workaround and finding a windows user who can test it.

User @cqexbesd responded (2017-May-07 14:37:38):

Second proposed fix (removing the use of .tmp altogether) is at https://github.com/cqexbesd/tools/tree/dlang_17216_v2. I don't have a copy of Windows so it needs testing - but it works under OSX.