Dear Albert ARIBAUD,
Am 08.01.2011 um 13:18 schrieb Albert ARIBAUD:
Le 08/01/2011 11:49, Albert ARIBAUD a écrit :
In my investigations for 'NULL fixup' (-> see http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/89864/focus=89906) pointed out that only symbols in 'absolute fixup' loop could be 'NULL' if there is a not aliased/empty weakly linked symbol.
BTW: is such a situation normal? IIUC, it means there is a weakly linked symbol without *any* defintion, *and* it is referenced in the code.
Yes you may have a weakly linked symbol which was declared but nowhere implemented. See http://patchwork.ozlabs.org/patch/73647, this fixed such a situation for arm920t/at91 style SoC.
BTW: Without the mentioned patch there was another issue with linking (-> see http://patchwork.ozlabs.org/patch/73563). The linker introduced a .plt section which could not be placed and lead to a segfault of linker.
Granted, maybe it is checked before it is referenced, but we may want to check for and report at build time if possible. Would that be useful?
AFAIR there was a statement to remove those 'undefined weakly linked symbols' from code. So it would be useful to have a tool to detect those symbols at build time.
regards
Andreas Bießmann