Re: static linking

Daniel Andrzejewski wrote:
> Hi all,
> 
> I have a problem with gcj. I have read couple threads here, but I still 
> have no idea how to fix my problem. Usually people say that this is hard 
> but doable, but they don't give much directions.
> 
> I'm trying to do it for a system where there's no shared libraries, so I 
> must not even dynamically link libc.

One might ask the question: Why?

> 
> I successfully build gcc 4.3.0 with --disable-shared option. I can 
> successfully compile a java program, but the executable is still 
> dynamically linked.
> 
> /scratch/daniel> ldd ./HelloWorld
>         libz.so.1 => /lib64/libz.so.1 (0x00002adcd28dd000)
>         libpthread.so.0 => /lib64/tls/libpthread.so.0 (0x00002adcd29f0000)
>         libc.so.6 => /lib64/tls/libc.so.6 (0x00002adcd2b04000)
>         libm.so.6 => /lib64/tls/libm.so.6 (0x00002adcd2d26000)
>         libdl.so.2 => /lib64/libdl.so.2 (0x00002adcd2e7d000)
>         librt.so.1 => /lib64/tls/librt.so.1 (0x00002adcd2f80000)
>         /lib64/ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 
> (0x00002adcd27c6000)
> 
> When I use -static flag while compiling I get some warnings, but the 
> executable gets compiled.
> 
> /scratch/daniel> gcj --main=HelloWorld -o HelloWorld -static 
> HelloWorld.java
> ...
> warnings
> ...

Do you know a priori that the content of the warnings is not relevant to this problem?  If not, please include them.

First start with only -static-libgcj to isolate C library problems from libgcj problems.


> /scratch/daniel> file HelloWorld
> HelloWorld: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for 
> GNU/Linux 2.4.1, statically linked, not stripped
> 
> 
> And the problem is at the runtime:
> 
> /scratch/daniel> ./HelloWorld
> Aborted
> 

That is not too helpful.  You need to run the thing under gdb and at a minimum see where it is failing (put a breakpoint on abort()). 


> 
> Has anyone solved this issue yet?
> 

I have not used a static glibc, but I successfully do static linking of libgcj.  Most problems come down to missing classes due to the linker not linking classes that are only referred to dynamically.

I put the following into my main code to force some necessary classes to be linked:

extern int _ZN3gnu4java6locale8Calendar6class$E;
int *dummy1 = &_ZN3gnu4java6locale8Calendar6class$E;

extern int _ZN3gnu4java6locale17LocaleInformation6class$E;
int *dummy2 = &_ZN3gnu4java6locale17LocaleInformation6class$E;

extern int _ZN3gnu3gcj7convert12Output_ASCII6class$E;
int *dummy3 = &_ZN3gnu3gcj7convert12Output_ASCII6class$E;

extern int _ZN3gnu3gcj7convert11Output_UTF86class$E;
int *dummy5 = &_ZN3gnu3gcj7convert11Output_UTF86class$E;

#ifdef STATIC_LIBGCJ_4_3
extern int _ZGr32_java$Sutil$Siso4217$_properties;
int *dummy6 = &_ZGr32_java$Sutil$Siso4217$_properties;

extern int _ZN3gnu3xml8aelfred29XmlParser6class$E;
int *dummy7 = &_ZN3gnu3xml8aelfred29XmlParser6class$E;

#endif


Note that either fewer or more classes may be needed by your application.