Re: OFFTOPIC: binary modules, bad idea!

Theodore Y. Ts'o (tytso@MIT.EDU)
Fri, 19 Dec 1997 18:16:17 -0500

Date: Fri, 19 Dec 1997 17:00:38 -0600
From: Michael Elizabeth Chastain <>

I want separate compilation.

Right now, if drivers/net/foo.o has an external symbol for kmalloc, it
depends on include/modules/slab.ver, which is generated from mm/slab.c.
So changes in mm/slab.c cause all modules to be rebuilt because type
information from mm/slab.c goes into all module files.

OK, so you're worried about the make dependencies problem, and not
needlessly forcing a module to get recompiled when it doesn't need to

However, storing the information in a separate ELF section doesn't solve
this, unless you actually have GCC generate the hash code. (If you store
the hash code in slab.ver, you'd still have the same problem.) In fact,
if you have GCC generate the hash code, it'd solve this problem whether
the hash code is stored as part of the symbol name, or in a separate ELF

The problem with this, of course, is that we'd be dependent on a
specially hacked version of GCC --- unless you can get these changes
into the FSF's GCC mainline, which can sometimes be a trick. (Just ask
the egcc people! :-)

- Ted