Re: [dpdk-dev] [PATCH] Don't combine '-r' and '--export-dynamic' linker options

[Rafael Avila de Espindola <espindola@scylladb.com>]

Hi Thomas,

Are you the right maintainer fer reviewing this patch?

Thanks,
Rafael

Rafael Ávila de Espíndola <espindola@scylladb.com> writes:

> Running ld with '-r' switches the linker to a very special mode where
> some other linker options don't make sense.
>
> In particular, '--export-dynamic' normally requires that all global
> symbols be included in the dynamic symbol table, but a .o file doesn't
> even have a dynamic symbol table.
>
> When given both options it looks like the gnu linker just ignores
> '--export-dynamic'.
>
> Unfortunately some versions of lld (https://lld.llvm.org/) have a bug
> that causes it to try to create a dynamic symbol table in the output
> .o file and ends up corrupting it
> (https://bugs.llvm.org/show_bug.cgi?id=43552). Current (git) version
> of lld now issues an error.
>
> This patch drops $(LDFLAGS) when using -r. With this patch I can build
> dpdk with lld.
>
> Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
> ---
>  mk/internal/rte.compile-pre.mk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mk/internal/rte.compile-pre.mk b/mk/internal/rte.compile-pre.mk
> index 0cf3791b4..6cd7e559a 100644
> --- a/mk/internal/rte.compile-pre.mk
> +++ b/mk/internal/rte.compile-pre.mk
> @@ -61,7 +61,7 @@ CHECK_EXPERIMENTAL = $(EXPERIMENTAL_CHECK) $(SRCDIR)/$(EXPORT_MAP) $@
>  
>  PMDINFO_GEN = $(RTE_SDK_BIN)/app/dpdk-pmdinfogen $@ $@.pmd.c
>  PMDINFO_CC = $(CC) $(CPPFLAGS) $(CFLAGS) $(EXTRA_CFLAGS) -c -o $@.pmd.o $@.pmd.c
> -PMDINFO_LD = $(CROSS)ld $(LDFLAGS) -r -o $@.o $@.pmd.o $@
> +PMDINFO_LD = $(CROSS)ld -r -o $@.o $@.pmd.o $@
>  PMDINFO_TO_O = if grep -q 'RTE_PMD_REGISTER_.*(.*)' $<; then \
>  	echo "$(if $V,$(PMDINFO_GEN),  PMDINFO $@.pmd.c)" && \
>  	$(PMDINFO_GEN) && \
> -- 
> 2.21.0