On Wed, Aug 26, 2009 at 04:56:49PM +0900, Magnus Damm wrote: > Hi Simon! > > On Wed, Aug 26, 2009 at 3:31 PM, Simon Horman<horms at verge.net.au> wrote: > > On Thu, Aug 20, 2009 at 10:14:19PM +0900, Magnus Damm wrote: > >> Kexec-tools 2.0.1 seems to build only with optimization enabled. If I > >> set CFLAGS before calling configure and remove the "-O2" then the code > >> won't link properly. I found it while cross compiling for SuperH, but > >> it's most likely an issue on other platforms as well. Have a look at > >> the "-O0" below: > >> > >> ?$ AR=_ar CC=_gcc CFLAGS="-O0" LDFLAGS="-static" ./configure > >> --prefix=/ --host="sh3-linux" --without-zlib --without-xen > > [snip] > > >> This issue is most likely related to get_unaligned() and > >> put_unaligned() having bad_unaligned_access_length() in their default > >> case that never gets optimized away. > >> > >> Anyway, not very important. But at least you know now. =) > > > > Hi Magnus, > > > > I'm some what dubious about this, but it appears to be intentional that > > get_unaligned() doesn't exist: > > > > ---- From kexec/kexec.h ---- > > > > /* > > ?* This function doesn't actually exist. ?The idea is that when someone > > ?* uses the macros below with an unsupported size (datatype), the linker > > ?* will alert us to the problem via an unresolved reference error. > > ?*/ > > Yes, I understand the purpose of the code and it makes sense. But the > data size in this case _is_ correct. The issue here seems to be that > the compiler is not optimizing away the default case reference unless > optimization is enabled. I'd suggest moving away from automatic type > size detection to have separate functions for each size. That would > make it possible to comple the code both with and without optimization > enabled. > > Or may I'm misunderstanding the issue? =) I think you are understanding it right, that the current code fails with no optimisation enabled because the unused function isn't optimised away. Is there a reason you need -O0? It seems that fixing this is probably more effort than its worth.
