Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 2 Nov 2017 11:53:53 -0700 | Subject | Re: [GIT PULL] License cleanup: add SPDX license identifiers to some kernel files |
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On Thu, Nov 2, 2017 at 11:21 AM, Thomas Gleixner <tglx@linutronix.de> wrote: > > The wreckage is with the *.lds.S ones which are used to generate .lds with > some gcc preprocessor magic. And then ld falls flat on its nose with the // > comment.
The cpp phase should just get rid of them.
But we actually explicitly use "cpp -C" for the lds file to keep comments around. Which makes no sense to me, but there it is.
That is *completely* crazy. I wonder why we do that brain-damage.
Literally just removing that -C fixes the problem:
- cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \ + cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
and there is no reason to keep them that I can possibly see.
Seriously, we should fix that regardless, but if it actually keeps us from having C++ style comments in header files that might be included in lds.S files, we should _definitely_ fix it.
It seems to be a historical oddity. The "-C" was added in 51b563fc93c8 ("arm, cris, mips, sparc, powerpc, um, xtensa: fix build with bash 4.0"), but it came from our old
export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH)
which predates the git history.
Hmm.. Digging down, long long ago we used to do
arch/$(ARCH)/vmlinux.lds.s: arch/$(ARCH)/vmlinux.lds.S $(CPP) $(CPPFLAGS) $(CPPFLAGS_$@) -P -C -U$(ARCH) $< -o $@
and that's where the -C comes from. And *that* came from MIPS, ia64 and sh doing so back in 2002.
But they used to use "-traditional" too.
So I'm pretty sure that the whole stupid "-C" is just a bogus result of history that should have been gotten rid of long long long ago.
Linus
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