Re: [PATCH 3/3] kbuild: remove AS variable

[Masahiro Yamada]

Hi Nick,


On Wed, Mar 25, 2020 at 4:59 AM Nick Desaulniers
<ndesaulniers@xxxxxxxxxx> wrote:
>
> On Tue, Mar 24, 2020 at 12:38 PM Nick Desaulniers
> <ndesaulniers@xxxxxxxxxx> wrote:
> > consistent in this regard (and not using the compiler as the driver),
>
> Ah, the preprocessor; we need to preprocess the .S files, .s files are
> fine (though we have .lds.S files that are not `-x
> assembler-with-cpp`)


Right, there is no '*.s' source file in the kernel tree.

If we want to de-couple $(AS), we must the compilation
before the assemble stage   ( $(CC) -S ), but
doing so does not buy us.

So, $(CC) always works as the front-end
for compiling both .c and .S files.


You can see the internal database by
'make --print-data-base'.

I see the following for  *.S -> *.o rule.

# default
COMPILE.S = $(CC) $(ASFLAGS) $(CPPFLAGS) $(TARGET_MACH) -c


So, using $(CC) is the right thing.


Even if we keep AS, we cannot do like AS=llvm-as
since llvm-as is a different kind of tool
that processes LLVM assembly (.ll) .


-- 
Best Regards
Masahiro Yamada