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
