static linking

Thu Aug 14 19:47:00 GMT 2008

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.