Using the llvm D-bindings

[Manuel König]

Am Wed, 06 Oct 2010 16:27:11 +0400
schrieb "Denis Koroskin" <2korden at gmail.com>:

> On Wed, 06 Oct 2010 16:20:41 +0400, Manuel König <manuelk89 at gmx.net>
> wrote:
> 
> > Hi,
> >
> > did anyone have success using the llvm-2.7 D-bindings from the
> > bindings project http://www.dsource.org/projects/bindings on x86_64
> > linux? I tried so far with ldc, but the compiler chokes about a
> > mere 3570 lines of unresolved symbols when linking with ldc,
> > compiling works fine.
> >
> > Short version:
> > ==============
> >
> > I think the question boils down to "How do I create a D library and
> > link it into a c++ program on x86_64 linux using ldc (or gdc or
> > <any_other_D_compiler>)".
> >
> > Long version:
> > =============
> > Here's a snip of the linker error messages I get from ldc:
> >
> > // -- file main.d
> > import llvm.c.Core;
> >
> > void main()
> > {
> >     auto context = LLVMGetGlobalContext();
> > }
> > // --
> >
> > $ ldc -I=/path/to/llvm-2.7 \
> > -L=/usr/local/lib/libLLVM{Core,Support,System}.a main.d
> > /usr/local/lib/libLLVMCore.a(Core.o): In function
> > `LLVMContextCreate': Core.cpp:(.text+0x57): undefined reference to
> > `operator new(unsigned long)'
> > /usr/local/lib/libLLVMCore.a(Core.o): In function
> > `LLVMModuleCreateWithName':
> > Core.cpp:(.text+0x13a): undefined reference to `operator
> > new(unsigned long)'
> > /usr/local/lib/libLLVMCore.a(Core.o): In function
> > `LLVMModuleCreateWithNameInContext':
> > Core.cpp:(.text+0x195): undefined reference to `operator
> > new(unsigned long)'
> > /usr/local/lib/libLLVMCore.a(Core.o): In function
> > `LLVMSetDataLayout': Core.cpp:(.text+0x240): undefined reference to
> > `std::basic_string<char, std::char_traits<char>,
> > std::allocator<char> >::basic_string(char const*, unsigned long,
> > std::allocator<char> const&)' Core.cpp:(.text+0x24f): undefined
> > reference to `std::basic_string<char, std::char_traits<char>,
> > std::allocator<char>
> >> ::assign(std::basic_string<char, std::char_traits<char>,
> >> std::allocator<char> > const&)'
> > Core.cpp:(.text+0x25e): undefined reference to
> > `std::basic_string<char, std::char_traits<char>,
> > std::allocator<char>
> >> ::_Rep::_S_empty_rep_storage'
> > Core.cpp:(.text+0x294): undefined reference to
> > `std::basic_string<char, std::char_traits<char>,
> > std::allocator<char>
> >> ::_Rep::_M_destroy(std::allocator<char> const&)'
> >> [...]
> >
> > After scanning over the error messages, I think it's only operator,
> > delete and std::* symbols that are missing. I also get the same
> > error messages when I try to compile an equivalent C program that
> > uses the llvm-c/* headers with gcc, but it works with g++, so I'm
> > quite sure the problem is the missing c++ runtime, which is
> > nonexistent in ldc.
> >
> > I think there are only two ways to solve this:
> >
> > (1) link the c++ runtime to ldc (I have no clue how to do that or if
> >     it's possible)
> > (2) Write a D library using the llvm D-bindings, define a semi-main
> >     function as extern(C), and write a c++ wrapper program that
> > links to the D library and does nothing more than calling the
> > semi-main function. The llvm symbols and c++ runtime will then be
> > linked in using g++.
> >
> > Option (2) seems easy, but ldc does not seem to have a linker swith
> > to build libraries, and doing
> >
> > ldc -c myprog.d # produces myprog.o
> > ar -cq myprog.a myprog.o
> >
> > to generate a library from the object file doesn't work because
> > there are still undefined symbols to the main function or the
> > module ctors in there, even when myprog.d doesn't define a main
> > function. I could try to hack those missing functions back in by
> > defining them in the C program, but there must be some simpler way
> > to generate libraries, or am I at a loosing front here?
> >
> > I also consider using other compilers than ldc as an option, but
> > afaik the only other usable compiler might be gdc (is that stable
> > by now?).
> 
> You should probably ask LDC guys (irc://irc.freenode.net/ldc)

Thanks, I'll try. But I think the development of LDC was put on hold
due to lack of time and interest, let's see if I can find someone
there :)