llvm dev - Jun 2006 - [LLVMdev] Compiling natively vsftp with LLVM

Hi,
I am using LLVM to compile vsftp to native x86 ELF code.
One of it's object file (sysdeputil) contains inline asm so cannot be
compiled by gcc-3.4 frontend.
So I decided to firstly link together the llvm objects and libcrtend and compile
it to native .o file and then link it with sysdeputil.o .

The Makefile is sth like this:

vsftpd: $(OBJS)
	gccld -r -native  -o vsftpd.o $(OBJS)
-L/home/xianai/my_projects/llvm/cfrontend/x86/llvm-gcc/lib/ -lcrtend
        gcc -o vsftpd vsftpd.o sysdeputil.o `./vsf_findlibs.sh`


But the gcc/ld still cannot find the reference to __main.
Do I have to compile crtend to native to solve this problem? 

-- 
Regards,
Nai

On Fri, 2 Jun 2006, Nai Xia wrote:
> The Makefile is sth like this:
>
> vsftpd: $(OBJS)
> 	gccld -r -native  -o vsftpd.o $(OBJS)
-L/home/xianai/my_projects/llvm/cfrontend/x86/llvm-gcc/lib/ -lcrtend
>        gcc -o vsftpd vsftpd.o sysdeputil.o `./vsf_findlibs.sh`
>
>
> But the gcc/ld still cannot find the reference to __main.
> Do I have to compile crtend to native to solve this problem?
gccld -r doesn't work with -native.  Also, you do need to link in crtend, 
which doesn't happen with -r, only "producing an executable mode"
links in
libraries.

-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

Hi, I have tried another way:

ar rcs libsysdeputil.a sysdeputil.o

gccld seems to recognize the file type. However, it stills find unresoved
symbols
which are actually the functions in sysdeputil.o (can be find out with `nm
libsysdeputil.a`)

The problem disappears if native gcc/ld tool chain is used.

As another test, main.c:
-----------------
extern void foo();
int main()
{
  foo();
  return 0;
}
----------------

foo.c 
---------------
#include <stdio.h.
void foo()
{
  printf("hello\n");
  return;
}
----------------

And the command lines:

llvm-gcc -c -o main.o main.c
gcc -o foo.o foo.c
ar rcs libfoo.a foo.o
llvm-gcc -Wl,-native main.o -L. -lfoo

It's *OK*

Thanks in advance for solving my problem. :)
And I personally think it may possiblely puzzle other users,
maybe it deserves its place in FAQ or in man page for LLVM.  


On Friday 02 June 2006 13:13, Chris Lattner wrote:
> On Fri, 2 Jun 2006, Nai Xia wrote:
> > The Makefile is sth like this:
> >
> > vsftpd: $(OBJS)
> > 	gccld -r -native  -o vsftpd.o $(OBJS)
-L/home/xianai/my_projects/llvm/cfrontend/x86/llvm-gcc/lib/ -lcrtend
> >        gcc -o vsftpd vsftpd.o sysdeputil.o `./vsf_findlibs.sh`
> >
> >
> > But the gcc/ld still cannot find the reference to __main.
> > Do I have to compile crtend to native to solve this problem?
> 
> gccld -r doesn't work with -native.  Also, you do need to link in
crtend,
> which doesn't happen with -r, only "producing an executable
mode" links in
> libraries.
> 
> -Chris
> 
-- 
Regards,
Nai