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Now, we got a basic ability to test compiler capability in Kconfig. config CC_HAS_STACKPROTECTOR def_bool $(shell,($(CC) -Werror -fstack-protector -E -x c /dev/null -o /dev/null 2>/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 that. Hence, here is another feature, user-defined function. This works as a textual shorthand with parameterization. A user-defined function is defined by using the = operator, and can be referenced in the same way as built-in functions. A user-defined function in Make is referenced like $(call my-func,arg1,arg2), but I omitted the 'call' to make the syntax shorter. The definition of a user-defined function contains $(1), $(2), etc. in its body to reference the parameters. It is grammatically valid to pass more or fewer arguments when calling it. We already exploit this feature in our makefiles; scripts/Kbuild.include defines cc-option which takes two arguments at most, but most of the callers pass only one argument. By the way, a variable is supported as a subset of this feature since a variable is "a user-defined function with zero argument". In this context, I mean "variable" as recursively expanded variable. I will add a different flavored variable in the next commit. The code above can be written as follows: [Example Code] success = $(shell,($(1)) >/dev/null 2>&1 && echo y || echo n) cc-option = $(success,$(CC) -Werror $(1) -E -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@socionext.com> |
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.. | ||
lxdialog | ||
tests | ||
.gitignore | ||
conf.c | ||
confdata.c | ||
expr.c | ||
expr.h | ||
gconf-cfg.sh | ||
gconf.c | ||
gconf.glade | ||
images.c | ||
kconf_id.c | ||
list.h | ||
lkc.h | ||
lkc_proto.h | ||
Makefile | ||
mconf-cfg.sh | ||
mconf.c | ||
menu.c | ||
merge_config.sh | ||
nconf-cfg.sh | ||
nconf.c | ||
nconf.gui.c | ||
nconf.h | ||
preprocess.c | ||
qconf-cfg.sh | ||
qconf.cc | ||
qconf.h | ||
streamline_config.pl | ||
symbol.c | ||
util.c | ||
zconf.l | ||
zconf.y |