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@xxxxxxxxx>: > > 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, $(call hostcc-option, ...) returns always an empty string here > whether the compiler supports the option or not. So calling a yet-to-be defined variable results in an empty string rather than a loud failure? Chalk that up there with language features no one ever asked for. That kind of implicit conversion gets languages like JavaScript (with its loose type system, not that C is without its own implicit type conversions/promotions) in a lot of hot water. If that's the case, why are includes not at the top of Makefiles, if silent failure is a possibility? Is there a reason the include is so far into the Makefile? Is your sugguestion to raise the include or lower the HOSTCFLAGS definition? > > -ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1) > > -HOSTCFLAGS += -Wno-unused-value -Wno-unused-parameter \ > > - -Wno-missing-field-initializers -fno-delete-null-pointer-checks > > -endif > > The logic is very strange in the first place. > > Even very old GCC supports -fno-delete-null-pointer-checks, > but clang does not. > > Here, -fno-delete-null-pointer-checks is added only when > we are using clang for HOSTCC. This is opposite. > > I guess we can remove all of them > unless somebody can explain the rationale. +llvm-linux I suppose maybe different ARCH's have different host binaries made during the build? I tested x86_64 and arm64. The commit message that added them missed any context or justification. -- 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
