>> I want to remind that question is *not* about removing run-time switch >> as concept, but rather about distinguishing pre-ARMv7 and ARMv>=7. I.e. >> NEON/cryto switch will stay, the only question if it's worth imposing it >> on pre-ARMv7 builds [assuming that such binaries will be executed even >> on ARMv>=7 systems]. > > Yes, that is perfectly clear. So we can target armv4 on the compiler > command line, and still get crypto instructions when executing the > resulting binary on a v8 system. > >>> So I would vote for #1, but with the .arch/.fpu declarations moved to >>> the asm files. >> This is undesired, because we don't want to make assumption that every >> assembler actually supports these directives and required values. It's >> safe to assume for big distro vendors, but there are people struggling >> with exotic toolchains. >> > > Well, in that case, will they be able to assemble the file in the > first place, even with some -Wa, switch added?
Yes, but developer would have the *freedom* to specify -Wa that matches specific environment. > I know we deal with that using #ifdef's now, but those should be dropped imo. I'd like to drop them too, but I don't see it as question of liking, at least not for now :-( > Perhaps we should introduce MIN_ARCH and MAX_ARCH variables, That's exactly what I meant by "convey the missing information by other means, by additional -D option." It looks like specifying maximum would be sufficient. I mean minimum would be controlled by -march to compiler and then -Wa -DMAX could complement it. > where the > defaults are v4 and v8 respectively, and we can add Configure targets > that narrow this down for targets like these? Right now there is only one linux-armv4, and there is no architecture-specific flag there. This implies that you either rely on compiler default or pass specific flag explicitly at configuration stage. ./config actually does exactly this by adding -march=armv7-a if executed on armv7 system. So as alternative to this you'd pass -march=armvmin -Wa,-march=armvmax -D*MAX*=max, thus putting all controls to users' hands. > ... #1 has my preference regardless. Got it. ______________________________________________________________________ OpenSSL Project http://www.openssl.org Development Mailing List openssl-dev@openssl.org Automated List Manager majord...@openssl.org
