Using the llvm D-bindings

[Denis Koroskin]

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)