[llvm-dev] ld.lld on MacOS question

[Peter Kriens via llvm-dev]

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'



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