On Fri, 2015-12-25 at 17:21 -0800, Mark Millard wrote: > In my view "-mno-unaligned-access" is an even bigger hammer than I > used. I find no clang statement about what its ABI consequences would > be, unlike for what I did: What mix of more padding for alignment vs. > more but smaller accesses? But as I remember I've seen "-mno > -unaligned-access" in use in ports and the like so its consequences > may be familiar material for some folks. > > Absent any questions about ABI consequences "-mno-unaligned-access" > does well mark the expected SCTLR bit[1] status, far better than what > I did. Again: I was covering my ignorance while making any > significant investigation/debugging as unlikely as I could.
After reading the docs more carefully, I think -mno-unaligned-access isn't a bigger hammer, it's just a different tool that addresses a different problem than the one you ran into, and it's one we need. In particular, it prevents alignment-required accesses to potentially unaligned fields in a struct marked as 'packed', which is something we rely on (it's why we mark some structs as packed). -- Ian _______________________________________________ freebsd-toolchain@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-toolchain To unsubscribe, send any mail to "freebsd-toolchain-unsubscr...@freebsd.org"
