[PATCH 1/3] lib/raid6/test/Makefile: Use `$(pound)` instead of `\#` for Make 4.3

[Song Liu]

Hi Paul,

Sorry for the delayed reply.

On Wed, Jan 26, 2022 at 3:42 AM Paul Menzel <pmenzel at molgen.mpg.de> wrote:
>
> Buidling `raid6test` on Ubuntu 21.10 (ppc64le) with GNU Make 4.3 shows the
> errors below:

Please do not use `xxx` in the commit log (and subject).

>
>     $ cd lib/raid6/test/
>     $ make
>     <stdin>:1:1: error: stray ‘\’ in program
>     <stdin>:1:2: error: stray ‘#’ in program
>     <stdin>:1:11: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘<’ token
>     cp -f ../int.uc int.uc
>     awk -f ../unroll.awk -vN=1 < int.uc > int1.c
>     gcc -I.. -I ../../../include -g -O2                      -c -o int1.o int1.c
>     awk -f ../unroll.awk -vN=2 < int.uc > int2.c
>     gcc -I.. -I ../../../include -g -O2                      -c -o int2.o int2.c
>     awk -f ../unroll.awk -vN=4 < int.uc > int4.c
>     gcc -I.. -I ../../../include -g -O2                      -c -o int4.o int4.c
>     awk -f ../unroll.awk -vN=8 < int.uc > int8.c
>     gcc -I.. -I ../../../include -g -O2                      -c -o int8.o int8.c
>     awk -f ../unroll.awk -vN=16 < int.uc > int16.c
>     gcc -I.. -I ../../../include -g -O2                      -c -o int16.o int16.c
>     awk -f ../unroll.awk -vN=32 < int.uc > int32.c
>     gcc -I.. -I ../../../include -g -O2                      -c -o int32.o int32.c
>     rm -f raid6.a
>     ar cq raid6.a int1.o int2.o int4.o int8.o int16.o int32.o recov.o algos.o tables.o
>     ranlib raid6.a
>     gcc -I.. -I ../../../include -g -O2                      -o raid6test test.c raid6.a
>     /usr/bin/ld: raid6.a(algos.o):/dev/shm/linux/lib/raid6/test/algos.c:28: multiple definition of `raid6_call'; /scratch/local/ccIJjN8s.o:/dev/shm/linux/lib/raid6/test/test.c:22: first defined here
>     collect2: error: ld returned 1 exit status
>     make: *** [Makefile:72: raid6test] Error 1
>
> The errors come from the `HAS_ALTIVEC` test, which fails, and the POWER
> optimized versions are not built. That’s also reason nobody noticed on the
> other architectures.
>
> GNU Make 4.3 does not remove the backslash anymore. From the 4.3 release
> announcment:
>
> > * WARNING: Backward-incompatibility!
> >   Number signs (#) appearing inside a macro reference or function invocation
> >   no longer introduce comments and should not be escaped with backslashes:
> >   thus a call such as:
> >     foo := $(shell echo '#')
> >   is legal.  Previously the number sign needed to be escaped, for example:
> >     foo := $(shell echo '\#')
> >   Now this latter will resolve to "\#".  If you want to write makefiles
> >   portable to both versions, assign the number sign to a variable:
> >     H := \#
> >     foo := $(shell echo '$H')
> >   This was claimed to be fixed in 3.81, but wasn't, for some reason.
> >   To detect this change search for 'nocomment' in the .FEATURES variable.
>
> So, do the same as commit 9564a8cf422d (Kbuild: fix # escaping in .cmd
> files for future Make) and commit 929bef467771 (bpf: Use $(pound) instead
> of \# in Makefiles) and define and use a `$(pound)` variable.

Please run ./scripts/checkpatch.pl against the patch files, and fix
errors/warnings
as much as possible.

Thanks,
Song

>
> Reference for the change in make:
> https://git.savannah.gnu.org/cgit/make.git/commit/?id=c6966b323811c37acedff05b57
>
> Cc: Matt Brown <matthew.brown.dev at gmail.com>
> Signed-off-by: Paul Menzel <pmenzel at molgen.mpg.de>
> ---
>  lib/raid6/test/Makefile | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile
> index a4c7cd74cff5..4fb7700a741b 100644
> --- a/lib/raid6/test/Makefile
> +++ b/lib/raid6/test/Makefile
> @@ -4,6 +4,8 @@
>  # from userspace.
>  #
>
> +pound := \#
> +
>  CC      = gcc
>  OPTFLAGS = -O2                 # Adjust as desired
>  CFLAGS  = -I.. -I ../../../include -g $(OPTFLAGS)
> @@ -42,7 +44,7 @@ else ifeq ($(HAS_NEON),yes)
>          OBJS   += neon.o neon1.o neon2.o neon4.o neon8.o recov_neon.o recov_neon_inner.o
>          CFLAGS += -DCONFIG_KERNEL_MODE_NEON=1
>  else
> -        HAS_ALTIVEC := $(shell printf '\#include <altivec.h>\nvector int a;\n' |\
> +        HAS_ALTIVEC := $(shell printf '$(pound)include <altivec.h>\nvector int a;\n' |\
>                           gcc -c -x c - >/dev/null && rm ./-.o && echo yes)
>          ifeq ($(HAS_ALTIVEC),yes)
>                  CFLAGS += -I../../../arch/powerpc/include
> --
> 2.34.1
>