On 2017-Apr-14, at 2:35 PM, Dimitry Andric <dimitry at andric.com> wrote:
> On 14 Apr 2017, at 22:40, Mark Millard <markmi at dsl-only.net> wrote: >> >> man src.conf (from -r315914 ) reports: >> >> WITH_LLD_IS_LD >> Set to use LLVM's LLD as the system linker, instead of GNU >> binutils ld. >> >> This is a default setting on arm64/aarch64. When set, these >> options are also in effect: >> >> WITHOUT_SYSTEM_COMPILER (unless WITH_SYSTEM_COMPILER is set >> explicitly) >> >> I'm curious about: >> >> A) Why there is a bias to avoid the system compiler? > > These are just the defaults, detected by the script that generates > src.conf.5. The setting of MK_SYSTEM_COMPILER is actually dependent on > the host, so it's technically incorrect to have src.conf.5 mention that > it is off by default. Ahh. I took the mention of WITH_LLD_IS_LD and WITHOUT_SYSTEM_COMPILER as it was written as something that was being specially enforced, implying some form of lack of full independence. I wondered about what contexts trying WITH_SYSTEM_COMPILER might be broken when WITH_LLD_IS_LD was also in use. >> and by contrast: >> >> B) What sort of context justifies explicitly setting >> WITH_SYSTEM_COMPILER when WITH_LLD_IS_LD is in use? > > The settings are mostly orthogonal. MK_SYSTEM_COMPILER was created to > avoid building a bootstrap compiler, if the system (host) compiler is > new enough. I'm familiar with the WITH_SYSTEM_COMPILER vintage material have have been using it and other such things right along. My worry for my knowledge-base would be the "mostly" part of "mostly orthogonal": When is there a lack of independence? (Presuming system-clang 4.0 instead of system-gcc 4.2.1.) > At some point you could also image a MK_SYSTEM_LINKER setting, which > would avoid building the bootstrap linker, if the system linker is new > enough. Yep. So it sounds like I can freely mix WITH_LLD_IS_LD and WITH_SYSTEM_COMPILER in any system-clang 4.0 based system build context, no actual problem cases, even if the existing system build used a binutils ld (for example). Thanks for the information. === Mark Millard markmi at dsl-only.net _______________________________________________ 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"
