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digitalmars.D - Dynamic loading of shared libraries.

reply Steve Teale <steve.teale britseyeview.com> writes:
Can DMD D2/Linux do this yet?
Jun 12 2011
next sibling parent Adam D. Ruppe <destructionator gmail.com> writes:
AFAIK, the situation is the same as when you asked last time. Still
on the list.
Jun 12 2011
prev sibling next sibling parent reply Jens Mueller <jens.k.mueller gmx.de> writes:
Content-Disposition: inline

Steve Teale wrote:

 Can DMD D2/Linux do this yet?


dmd can't do it yet. But if all you want is to link a against a shared
library you can try the following:

1. Create a shared library
$ gcc -m64 -fPIC -shared shared.c -o libshared.so

2. Building (without linking using dmd)
$ dmd -m64 -c dynamic.d -ofdynamic.o

3. Use gcc as linker
$ gcc -m64 dynamic.o /path/to//libphobos2.a -L. -lshared -lrt -o dynamic

4. Execute
$ ./dynamic
Hello from shared

I attached the files shared.c and dynamic.d, if you want to try
yourself.

Jens
Jun 13 2011
parent reply Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:
On 6/13/11 4:27 AM, Jens Mueller wrote:

 Steve Teale wrote:

 Can DMD D2/Linux do this yet?


 dmd can't do it yet. But if all you want is to link a against a shared
 library you can try the following:

 1. Create a shared library
 $ gcc -m64 -fPIC -shared shared.c -o libshared.so

 2. Building (without linking using dmd)
 $ dmd -m64 -c dynamic.d -ofdynamic.o

 3. Use gcc as linker
 $ gcc -m64 dynamic.o /path/to//libphobos2.a -L. -lshared -lrt -o dynamic

 4. Execute
 $ ./dynamic
 Hello from shared

 I attached the files shared.c and dynamic.d, if you want to try
 yourself.

 Jens


Jens,


Two questions - first, what steps do we need to take to convince the 
linker call from within dmd to work as above?

Second, how about the converse - loading a shared library from a program 
written in either C or D?


Thanks,

Andrei
Jun 13 2011
next sibling parent reply Robert Clipsham <robert octarineparrot.com> writes:
On 13/06/2011 14:32, Andrei Alexandrescu wrote:

 Two questions - first, what steps do we need to take to convince the
 linker call from within dmd to work as above?

 Second, how about the converse - loading a shared library from a program
 written in either C or D?


I was under the impression that dmd couldn't produce shared libraries in 
its current state - doesn't its output clobber the PIC register or 
something when compiling with -fPIC?

http://d.puremagic.com/issues/show_bug.cgi?id=4583


 Thanks,

 Andrei



-- 
Robert
http://octarineparrot.com/
Jun 13 2011
parent Jacob Carlborg <doob me.com> writes:
On 2011-06-13 16:19, Robert Clipsham wrote:

 On 13/06/2011 14:32, Andrei Alexandrescu wrote:

 Two questions - first, what steps do we need to take to convince the
 linker call from within dmd to work as above?

 Second, how about the converse - loading a shared library from a program
 written in either C or D?


 I was under the impression that dmd couldn't produce shared libraries in
 its current state - doesn't its output clobber the PIC register or
 something when compiling with -fPIC?

 http://d.puremagic.com/issues/show_bug.cgi?id=4583


 Thanks,

 Andrei




That's correct. And the runtime also will need a couple of changes as 
well. Like initializing module info, i.e. module constructors, exception 
handling tables and so on.

-- 
/Jacob Carlborg
Jun 17 2011
prev sibling parent reply Jens Mueller <jens.k.mueller gmx.de> writes:
Andrei Alexandrescu wrote:

 On 6/13/11 4:27 AM, Jens Mueller wrote:

Steve Teale wrote:

Can DMD D2/Linux do this yet?


dmd can't do it yet. But if all you want is to link a against a shared
library you can try the following:

1. Create a shared library
$ gcc -m64 -fPIC -shared shared.c -o libshared.so

2. Building (without linking using dmd)
$ dmd -m64 -c dynamic.d -ofdynamic.o

3. Use gcc as linker
$ gcc -m64 dynamic.o /path/to//libphobos2.a -L. -lshared -lrt -o dynamic

4. Execute
$ ./dynamic
Hello from shared

I attached the files shared.c and dynamic.d, if you want to try
yourself.

Jens


 
 Jens,
 
 
 Two questions - first, what steps do we need to take to convince the
 linker call from within dmd to work as above?


Never thought about that. Just tried.
$ dmd -m64 dynamic.o /path/to/libphobos2.a -L-L. -L-lshared -L-lrt -ofdynamic
works.


 Second, how about the converse - loading a shared library from a
 program written in either C or D?


Don't know exactly what you mean. As far as I know dmd is not able to
generate shared libraries. Is that your question?

Jens
Jun 13 2011
parent reply Andrei Alexandrescu <SeeWebsiteForEmail erdani.org> writes:
On 6/13/11 10:33 AM, Jens Mueller wrote:

 Andrei Alexandrescu wrote:

 On 6/13/11 4:27 AM, Jens Mueller wrote:

 Steve Teale wrote:

 Can DMD D2/Linux do this yet?


 dmd can't do it yet. But if all you want is to link a against a shared
 library you can try the following:

 1. Create a shared library
 $ gcc -m64 -fPIC -shared shared.c -o libshared.so

 2. Building (without linking using dmd)
 $ dmd -m64 -c dynamic.d -ofdynamic.o

 3. Use gcc as linker
 $ gcc -m64 dynamic.o /path/to//libphobos2.a -L. -lshared -lrt -o dynamic

 4. Execute
 $ ./dynamic
 Hello from shared

 I attached the files shared.c and dynamic.d, if you want to try
 yourself.

 Jens


 Jens,


 Two questions - first, what steps do we need to take to convince the
 linker call from within dmd to work as above?


 Never thought about that. Just tried.
 $ dmd -m64 dynamic.o /path/to/libphobos2.a -L-L. -L-lshared -L-lrt -ofdynamic
 works.


Great. Wonder why the path to Phobos is still needed - does using -L 
preclude all implicit uses of it?


 Second, how about the converse - loading a shared library from a
 program written in either C or D?


 Don't know exactly what you mean. As far as I know dmd is not able to
 generate shared libraries. Is that your question?


Yah, I was wondering if it's just PIC generation or something extra.


Andrei
Jun 13 2011
next sibling parent Jens Mueller <jens.k.mueller gmx.de> writes:
Andrei Alexandrescu wrote:

 On 6/13/11 10:33 AM, Jens Mueller wrote:

Andrei Alexandrescu wrote:

On 6/13/11 4:27 AM, Jens Mueller wrote:

Steve Teale wrote:

Can DMD D2/Linux do this yet?


dmd can't do it yet. But if all you want is to link a against a shared
library you can try the following:

1. Create a shared library
$ gcc -m64 -fPIC -shared shared.c -o libshared.so

2. Building (without linking using dmd)
$ dmd -m64 -c dynamic.d -ofdynamic.o

3. Use gcc as linker
$ gcc -m64 dynamic.o /path/to//libphobos2.a -L. -lshared -lrt -o dynamic

4. Execute
$ ./dynamic
Hello from shared

I attached the files shared.c and dynamic.d, if you want to try
yourself.

Jens


Jens,


Two questions - first, what steps do we need to take to convince the
linker call from within dmd to work as above?


Never thought about that. Just tried.
$ dmd -m64 dynamic.o /path/to/libphobos2.a -L-L. -L-lshared -L-lrt -ofdynamic
works.


 
 Great. Wonder why the path to Phobos is still needed - does using -L
 preclude all implicit uses of it?


No. You're right. It works without the path to Phobos.


Second, how about the converse - loading a shared library from a
program written in either C or D?


Don't know exactly what you mean. As far as I know dmd is not able to
generate shared libraries. Is that your question?


 
 Yah, I was wondering if it's just PIC generation or something extra.


There have been some posts regarding support for shared libraries. On
top of my head there we're at least 5 things that need to be done to get
it working.
$ dmd -m64 -L-shared shared.d -oflibshared.so
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o:
relocation R_X86_64_32S against `__libc_csu_fini' can not be used when making a
shared object; recompile with -fPIC
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o: could not read
symbols: Bad value
collect2: ld returned 1 exit status
--- errorlevel 1

I do not fully understand the error. But I believe there is something
wrong with dmd generating PIC.

Jens
Jun 13 2011
prev sibling next sibling parent Brad Roberts <braddr puremagic.com> writes:
On Mon, 13 Jun 2011, Jens Mueller wrote:


 There have been some posts regarding support for shared libraries. On
 top of my head there we're at least 5 things that need to be done to get
 it working.
 $ dmd -m64 -L-shared shared.d -oflibshared.so
 /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o:
relocation R_X86_64_32S against `__libc_csu_fini' can not be used when making a
shared object; recompile with -fPIC
 /usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o: could not read
symbols: Bad value
 collect2: ld returned 1 exit status
 --- errorlevel 1
 
 I do not fully understand the error. But I believe there is something
 wrong with dmd generating PIC.
 
 Jens


When building a shared library, you must build with -fPIC.  That's likely 
not sufficient to get it actually fully working with dmd.

so:  dmd -m64 -fPIC -L-shared shared.d -oflibshared.so

That said, combining not-well-tested .so support with 64 bit is a good way 
to discover new bugs, so go for it! :)

Later,
Brad
Jun 13 2011
prev sibling next sibling parent Jens Mueller <jens.k.mueller gmx.de> writes:
Brad Roberts wrote:

 On Mon, 13 Jun 2011, Jens Mueller wrote:
 

 There have been some posts regarding support for shared libraries. On
 top of my head there we're at least 5 things that need to be done to get
 it working.
 $ dmd -m64 -L-shared shared.d -oflibshared.so
 /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o:
relocation R_X86_64_32S against `__libc_csu_fini' can not be used when making a
shared object; recompile with -fPIC
 /usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o: could not read
symbols: Bad value
 collect2: ld returned 1 exit status
 --- errorlevel 1
 
 I do not fully understand the error. But I believe there is something
 wrong with dmd generating PIC.
 
 Jens


 
 When building a shared library, you must build with -fPIC.  That's likely 
 not sufficient to get it actually fully working with dmd.
 
 so:  dmd -m64 -fPIC -L-shared shared.d -oflibshared.so


Yes. I actually built using -fPIC but pasted the wrong line. Anyway both
lines result in the same above error.


 That said, combining not-well-tested .so support with 64 bit is a good way 
 to discover new bugs, so go for it! :)


You say not-well-tested .so support. I thought it's still under
construction. I'm on dmd 2.053.

Jens
Jun 13 2011
prev sibling parent Jacob Carlborg <doob me.com> writes:
On 2011-06-13 18:19, Andrei Alexandrescu wrote:

 On 6/13/11 10:33 AM, Jens Mueller wrote:

 Andrei Alexandrescu wrote:

 On 6/13/11 4:27 AM, Jens Mueller wrote:

 Steve Teale wrote:

 Can DMD D2/Linux do this yet?


 dmd can't do it yet. But if all you want is to link a against a shared
 library you can try the following:

 1. Create a shared library
 $ gcc -m64 -fPIC -shared shared.c -o libshared.so

 2. Building (without linking using dmd)
 $ dmd -m64 -c dynamic.d -ofdynamic.o

 3. Use gcc as linker
 $ gcc -m64 dynamic.o /path/to//libphobos2.a -L. -lshared -lrt -o
 dynamic

 4. Execute
 $ ./dynamic
 Hello from shared

 I attached the files shared.c and dynamic.d, if you want to try
 yourself.

 Jens


 Jens,


 Two questions - first, what steps do we need to take to convince the
 linker call from within dmd to work as above?


 Never thought about that. Just tried.
 $ dmd -m64 dynamic.o /path/to/libphobos2.a -L-L. -L-lshared -L-lrt
 -ofdynamic
 works.


 Great. Wonder why the path to Phobos is still needed - does using -L
 preclude all implicit uses of it?


 Second, how about the converse - loading a shared library from a
 program written in either C or D?


 Don't know exactly what you mean. As far as I know dmd is not able to
 generate shared libraries. Is that your question?


 Yah, I was wondering if it's just PIC generation or something extra.


 Andrei


The runtime needs a couple of changes as well, for example module info, 
i.e. module constructors, exception handling tables and so on.

-- 
/Jacob Carlborg
Jun 17 2011
prev sibling parent Kai Meyer <kai unixlords.com> writes:
On 06/12/2011 07:44 AM, Steve Teale wrote:

 Can DMD D2/Linux do this yet?


Sure, why not? Just use libdl. I've attached a zip file that should work 
like this:
$ unzip libdl_example.zip
$ ./build_run.sh
printer1(0)
Valx=5
printer1(0)
Valx=5
Jun 13 2011