On Mon, Mar 26, 2018 at 10:29 PM, Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote: > Now, we got a basic ability to test compiler capability in Kconfig. > > config CC_HAS_STACKPROTECTOR > def_bool $(shell (($CC -Werror -fstack-protector -c -x c /dev/null -o /dev/null) && echo y) || echo n) > > This works, but it is ugly to repeat this long boilerplate. > > We want to describe like this: > > config CC_HAS_STACKPROTECTOR > bool > default $(cc-option -fstack-protector) > > It is straight-forward to add a new function, but I do not like to > hard-code specialized functions like this. Hence, here is another > feature to add functions from Kconfig files. > > A user-defined function is defined with a special keyword 'macro'. > It can be referenced in the same way as built-in functions. This > feature was also inspired by Makefile where user-defined functions > are referenced by $(call func-name, args...), but I omitted the 'call' > to makes it shorter. > > The macro definition can contain $(1), $(2), ... which will be replaced > with arguments from the caller. The macro works just as a textual > shorthand, which is also expanded in the lexer phase. > > [Example Code] > > macro success $(shell ($(1) && echo y) || echo n) > > config TRUE > bool "true" > default $(success true) > > config FALSE > bool "false" > default $(success false) > > [Result] > > $ make -s alldefconfig > $ tail -n 2 .config > CONFIG_TRUE=y > # CONFIG_FALSE is not set > > [Example Code] > > macro success $(shell ($(1) && echo y) || echo n) > > macro cc-option $(success $CC -Werror $(1) -c -x c /dev/null -o /dev/null) > > config CC_HAS_STACKPROTECTOR > def_bool $(cc-option -fstack-protector) > > [Result] > $ make -s alldefconfig > $ tail -n 1 .config > CONFIG_CC_HAS_STACKPROTECTOR=y > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Cool, I like this "macro" idea for keeping this clean. > --- > > Reminder for myself: > Update Documentation/kbuild/kconfig-language.txt Yes please. :) Otherwise, looks good! -Kees -- Kees Cook Pixel Security -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
