On 01/15, Jakub Kicinski wrote:
> On Tue, 15 Jan 2019 11:59:53 -0800, Stanislav Fomichev wrote:
> > On some platforms, in order to link against libbfd, we need to
> > link against liberty and even possibly libz. Account for that
> > in the bpftool Makefile. We now have proper feature detection
> > for each case, so handle each one separately.
> >
> > See recent commit 14541b1e7e72 ("perf build: Don't unconditionally link the
> > libbfd feature test to -liberty and -lz") where I fixed feature
> > detection.
> >
> > Fixes: 29a9c10e4110 ("bpftool: make libbfd optional")
> > Signed-off-by: Stanislav Fomichev <s...@google.com>
>
> Minor nits below, in any case:
>
> Acked-by: Jakub Kicinski <jakub.kicin...@netronome.com>
>
> Thanks for making bpftool build! :)
>
> > diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> > index 492f0f24e2d3..af9a25bf480d 100644
> > --- a/tools/bpf/bpftool/Makefile
> > +++ b/tools/bpf/bpftool/Makefile
> > @@ -92,10 +92,21 @@ BFD_SRCS = jit_disasm.c
> >
> > SRCS = $(filter-out $(BFD_SRCS),$(wildcard *.c))
> >
> > -ifeq ($(feature-libbfd),1)
> > +ifeq ($(feature-libbfd), 1)
>
> nit: no space there is more common
>
> $ git grep 'ifeq' | grep ',[^ ]' | wc -l
> 482
> $ git grep 'ifeq' | grep ', ' | wc -l
> 136
>
>
> > +LIBS += -lbfd -ldl -lopcodes
>
> nit: should this be indented?
>
> > +else
> > + ifeq ($(feature-libbfd-liberty), 1)
> > + LIBS += -lbfd -ldl -lopcodes -liberty
> > + else
> > + ifeq ($(feature-libbfd-liberty-z), 1)
> > + LIBS += -lbfd -ldl -lopcodes -liberty -lz
> > + endif
>
> Would this syntax:
>
> ifeq ($(feature-libbfd),1)
> LIBS += ..
> else ifeq ($(feature-libbfd-liberty),1)
> LIBS += ..
> else ifeq ($(feature-libbfd-liberty-z),1)
> LIBS += ..
> endif
>
> Not work?
I does seem to work :-) This is the first time I see it being written that
way. (but your link indeed shows that this syntax is supported)
I'll post v2 shortly with all the nits addressed. Thanks for a quick
review!
>
> https://www.gnu.org/software/make/manual/html_node/Conditional-Syntax.html
>
> I don't think I've ever tried, but looks more concise..
>
> > + endif
> > +endif
> > +
> > +ifneq ($(filter -lbfd,$(EXTLIBS)),)
> > CFLAGS += -DHAVE_LIBBFD_SUPPORT
> > SRCS += $(BFD_SRCS)
> > -LIBS += -lbfd -lopcodes
> > endif
> >
> > OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
>
