[llvmlinux] [PATCH] kbuild: clang: remove crufty HOSTCFLAGS
segher at kernel.crashing.org
Sun Oct 1 00:38:53 UTC 2017
On Sat, Sep 30, 2017 at 04:14:50PM -0700, Nick Desaulniers wrote:
> On Thu, Sep 28, 2017 at 07:52:35PM +0900, Masahiro Yamada wrote:
> > 2017-09-26 11:28 GMT+09:00 Nick Desaulniers <nick.desaulniers at gmail.com>:
> > > HOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 \
> > > + $(call hostcc-option,-fno-delete-null-pointer-checks) \
> > > -fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS)
> > You call hostcc-option
> > before Kbuild.include is included around line 341.
> > So, $(call hostcc-option, ...) returns always an empty string here
> > whether the compiler supports the option or not.
> So calling a yet-to-be defined variable results in an empty string
> rather than a loud failure? Chalk that up there with language features
> no one ever asked for. That kind of implicit conversion gets languages
> own implicit type conversions/promotions) in a lot of hot water.
(and it warns all over the place during a kernel build -- having undefined
variables expand to the empty string is a useful feature, too, not just a
trap for the unwary).
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