Messages in this thread | | | From | Masahiro Yamada <> | Date | Wed, 21 Feb 2018 16:38:25 +0900 | Subject | Re: [PATCH 00/23] kconfig: move compiler capability tests to Kconfig |
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2018-02-20 0:18 GMT+09:00 Ulf Magnusson <ulfalizer@gmail.com>:
>> >> I'm not happy that we in one context can reference CONFIG variables >> directly, but inside the $(call ...) and $(shell ...) needs the $ prefix. >> But I could not come up with something un-ambigious where this could be avoided. > > I think we should be careful about allowing references to config > symbols. It mixes up the parsing and evaluation phases, since $() is > expanded during parsing (which I consider a feature and think is > needed to retain sanity). > > Patch 06/23 removes the last existing instance of symbol references in > strings by getting rid of 'option env'. That's an improvement to me. > We shouldn't add it back.
This is really important design decision, so I'd like to hear a little more from experts.
For example, x86 allows users to choose sub-arch, either 'i386' or 'x86_64'.
https://github.com/torvalds/linux/blob/v4.16-rc2/arch/x86/Kconfig#L4
If the user toggles CONFIG_64BIT, the bi-arch compiler will work in a slightly different mode (at least, back-end parts)
So, my question is, is there a case,
$(cc-option, -m32 -foo) is y, but $(cc-option, -m64 -foo) is n ? (or vice versa)
If the answer is yes, $(cc-option -foo) would have to be re-calculated every time CONFIG_64BIT is toggled.
This is what I'd like to avoid, though.
-- Best Regards Masahiro Yamada
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