[llvm-dev] ld.lld on MacOS question

[Andrew Kelley via llvm-dev]

Zig author here in the same boat. Looks like I'm going to have to disable
cross compiling for MacOS and when compiling native for MacOS add a
dependency on the system linker. Really looking forward to Mach-O support
in LLD, because at that point my users will be able to cross compile for
any OS out of the box.

On Thu, May 11, 2017 at 1:37 PM, Peter Kriens via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Thanks for the answer. However, this means I need a different linker for
> MacOS as for Windows/Linux?
>
> I guess it is a not a major thing but I was hoping to set up a cross
> compile env. where only the header files and shared libraries differed :-(
> I guess we’re not there yet … :-)
>
> Kind regards,
>
> Peter Kriens
>
> On 6 May 2017, at 19:57, Lang Hames <lhames at gmail.com> wrote:
>
> LLD work on Darwin is stalled out at the moment. Patches are welcome (and
> I'll try to find time to review them), but I'd recommend ld64 for any
> real-world linking.
>
> - Lang.
>
>
> On Thu, Apr 27, 2017 at 11:06 AM, Rui Ueyama <ruiu at google.com> wrote:
>
>> Cc'ing people who are working on macOS.
>>
>> On Thu, Apr 27, 2017 at 9:05 AM, Peter Kriens via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Hopefully the right list … otherwise pointers appreciated (I’ve spent
>>> days trying to find a solution but could not find sufficient documentation,
>>> could not find a proper list of -flavor darwin commands)
>>>
>>> I am setting up an environment for cross compiling shared libraries
>>> using LLVM. Overall this works perfectly for many unix like environments
>>> but MacOS is a pain in the ass despite that I am running on MacOS. (I’ve
>>> not tried windows yet.)
>>>
>>> I seem to be able to compile with clang a proper mach object file for a
>>> hello function. However, when I link this function into a shared library I
>>> (surprisingly for a shared lib?) get undefined symbols like _printf, stub
>>> runtime: dyld_stub_binder, _main, etc. Using the flag
>>>
>>> -undefined dynamic_lookup
>>>
>>> I get no errors or warnings but then when I try to link the shared
>>> library to a main program I get the error:
>>>
>>> ld: malformed dylib has MH_NO_REEXPORTED_DYLIBS flag
>>> but no LC_REEXPORT_DYLIB load commands: ./libhello.dylib file
>>> './libhello.dylib'
>>>
>>> I’ve included the shell file that makes the hello shared lib and the
>>> command that I use to link the file.
>>>
>>> Thanks for any help, this looks like an amazing solution if it can get
>>> to work on all supported platforms.
>>>
>>> Kind regards,
>>>
>>> Peter Kriens
>>>
>>> $ /usr/local/Cellar/llvm/4.0.0_1/bin/clang \
>>> -target x86_64-apple-darwin16.5.0 \
>>> -Ienvs/x86_64/apple/macos/darwin/16.5.0/include  \
>>> -v \
>>> -nostdinc \
>>> -fPIC \
>>> -c \
>>> -Wno-nullability-completeness \
>>> hello.c x.c
>>>
>>> $ file hello.o
>>> hello.o: Mach-O 64-bit object x86_64
>>>
>>> $ /usr/local/Cellar/llvm/4.0.0_1/bin/ld.lld \
>>> -flavor darwin \
>>> -v \
>>> -sdk_version 10.5.0 \
>>> -demangle \
>>> -arch x86_64 \
>>> -undefined dynamic_lookup \
>>> -dylib \
>>> -dynamic \
>>> -o libhello.dylib \
>>> hello.o
>>>
>>> $ file libhello.dylib
>>> libhello.dylib: Mach-O 64-bit dynamically linked shared library x86_64
>>>
>>> $ gcc x.c -L. -lhello
>>> ld: malformed dylib has MH_NO_REEXPORTED_DYLIBS flag but no
>>> LC_REEXPORT_DYLIB load commands: ./libhello.dylib file ‘./libhello.dylib'
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>
>
>
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