[Ecls-list] Missing symbols when embedding a static lib into a FAS file

Maciek Pasternacki maciekp at japhy.fnord.org
Tue Mar 14 10:33:01 UTC 2006

On Pungenday, Chaos 73, 3172 YOLD, Juan Jose Garcia Ripoll wrote:

> On Mon, 2006-03-13 at 14:15 +0100, Goffioul Michael wrote:
>> I'm facing a linkage problem when trying to build our framework on Linux
>> (it works OK under Windows). The problem is the following:
>> 1) several LISP files are compiled and linked into a static lib with
>> c::build-static-lib
>> 	-> (c::build-static-library "mylib" :lisp-files '(<my objects>))
>> => libmylib.a
>> 2) a FAS file is generated using this static lib, with c::build-fasl
>> 	-> (c::build-fasl "myfas" :lisp-files '(mylib)) => myfas.fas
>> Step 1 will generate a static lib containing the symbol init_MYLIB to
>> initialize the module. Step 2 will generate a dynamic lib containing the symbol
>> init_CODE, which in turn calls init_MYLIB. Now, this function call is indirect, as
>> init_MYLIB symbol is searched by name using ecl_library_symbol. As the symbol init_MYLIB do
>> not actually appear in the init_CODE function of the fas file, the linker will NOT
>> embed the corresponding code in the generated FAS file. The result is that loading
>> the resulting FAS file just segfaults (indeed, ecl_library_symbol will return NULL)
>> Is there a workaround for this problem?
> Would this be solved if you join steps 1) and 2) ? I mean passing the
> list of object files to build-fasl instead of the library.
> I suspect this is not a solution. I remember that this change was
> introduced by Maciek to solve some name collisions in Linux, as shown in
> the log:
> revision 1.79
> date: 2005/05/26 22:46:34;  author: japhie;  state: Exp;  lines: +6 -3
> When linking a fasl, find individual objects' entry function in the
> same fasl only by ecl_library_symbol instead of relying on dynamic
> linker (avoids filename/entry-function-name conflicts).
> But now I have problems remembering what caused these conflicts.
> Probably similar function names from different FASL files and the
> current dll pulling the name out of a different FASL when one compiles
> direct calls. Maybe he can remind us :-)

Conflicts was caused by loading different FASL files with the same
name (and, maybe, by renaming fasl files).  I'm not tracking ecls
project actively at the moment and feel free to fix your problems in
any way you feel suitable; when I get back to my ecls project (not
soon), I'll check if it creates any problems (there will probably be
some more incompatibilities...).


__    Maciek Pasternacki <maciekp at japhy.fnord.org> [ http://japhy.fnord.org/ ]
`| _   |_\  / { Razors pain you; rivers are damp; acids stain you; and drugs
,|{-}|}| }\/ cause cramp.  Guns aren't lawful; nooses give; gas smells awful;
\/   |____/ you might as well live.               }  (  Dorothy Parker )  -><-

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