Hi Gage, +CC Thomas, Bruce
On Mon, Oct 02, 2017 at 08:48:29PM +0000, Eads, Gage wrote: > I believe I've spotted an issue in the way inter-PMD dependencies are handled > when building shared libraries. The depdirs_rule in mk/rte.subdir.mk relies > on DEPDIRS-xyz containing the names of subdirectories that xyz depends on. In > mk/rte.lib.mk, these DEPDIRS are converted into LDLIBS. This works when the > subdirectory names match the library names (i.e. any of the libraries under > lib/). However when the dependency is on a PMD, the subdirectory and library > names don't match. > > This is a problem, for example, in a patch for the net/octeontx PMD, which > has a dependency on the event/octeontx PMD: > http://dpdk.org/ml/archives/dev/2017-August/073983.html > > I've reproduced this with a contrived example, by making the failsafe PMD > depend on the NULL PMD in drivers/net/Makefile: > -DEPDIRS-failsafe = $(core-libs) > +DEPDIRS-failsafe = $(core-libs) librte_pmd_null > > You can reproduce the build failure by running this command: > ./devtools/test-build.sh > x86_64-native-linuxapp-gcc+CONFIG_RTE_BUILD_SHARED_LIB > > I'm no expert on DPDK's dependency handling code, but one option is to modify > rte.lib.mk like so: > -LDLIBS += $(subst lib,-l,$(_LDDIRS)) > +LDLIBS += $(subst lib,-l,$(filter lib%,$(_LDDIRS))) > > Then you could put the PMD's directory name in DEPDIRs, and specify the > depended-on library in the PMD's LDLIBS (as is done in the aforementioned > net/octeontx PMD). > > Thoughts? Thanks for spotting this. Indeed, generating the "-l lib" LDFLAG from DEPDIR doesn't work for PMDs. Here is the list of libraries whose directory name is different than library name: $ git grep "LIB = " | while read line; do dir=$(basename ${line%/Makefile*}); lib=${line#*= }; lib=${lib%*.a}; if [ "$dir" != "$lib" ]; then echo "${dir} ${lib}"; fi; done fslmc librte_bus_fslmc aesni_gcm librte_pmd_aesni_gcm aesni_mb librte_pmd_aesni_mb armv8 librte_pmd_armv8 dpaa2_sec librte_pmd_dpaa2_sec kasumi librte_pmd_kasumi null librte_pmd_null_crypto openssl librte_pmd_openssl qat librte_pmd_qat scheduler librte_pmd_crypto_scheduler snow3g librte_pmd_snow3g zuc librte_pmd_zuc dpaa2 librte_pmd_dpaa2_event octeontx librte_pmd_octeontx_ssovf skeleton librte_pmd_skeleton_event sw librte_pmd_sw_event dpaa2 librte_mempool_dpaa2 ring librte_mempool_ring stack librte_mempool_stack af_packet librte_pmd_af_packet ark librte_pmd_ark avp librte_pmd_avp bnx2x librte_pmd_bnx2x bnxt librte_pmd_bnxt bonding librte_pmd_bond cxgbe librte_pmd_cxgbe dpaa2 librte_pmd_dpaa2 e1000 librte_pmd_e1000 ena librte_pmd_ena enic librte_pmd_enic failsafe librte_pmd_failsafe fm10k librte_pmd_fm10k i40e librte_pmd_i40e ixgbe librte_pmd_ixgbe kni librte_pmd_kni liquidio librte_pmd_lio mlx4 librte_pmd_mlx4 mlx5 librte_pmd_mlx5 nfp librte_pmd_nfp null librte_pmd_null pcap librte_pmd_pcap qede librte_pmd_qede ring librte_pmd_ring sfc librte_pmd_sfc_efx szedata2 librte_pmd_szedata2 tap librte_pmd_tap thunderx librte_pmd_thunderx_nicvf vhost librte_pmd_vhost virtio librte_pmd_virtio vmxnet3 librte_pmd_vmxnet3_uio xenvirt librte_pmd_xenvirt lib librte_ethtool eal librte_eal librte_ether librte_ethdev If we don't consider the ones where we can add "librte_pmd_", the list is smaller, but there are still many: $ git grep "LIB = " | while read line; do dir=$(basename ${line%/Makefile*}); lib=${line#*= }; lib=${lib%*.a}; if [ "$dir" != "$lib" -a "librte_pmd_$dir" != "$lib" ]; then echo "${dir} ${lib}"; fi; done fslmc librte_bus_fslmc null librte_pmd_null_crypto scheduler librte_pmd_crypto_scheduler dpaa2 librte_pmd_dpaa2_event octeontx librte_pmd_octeontx_ssovf skeleton librte_pmd_skeleton_event sw librte_pmd_sw_event dpaa2 librte_mempool_dpaa2 ring librte_mempool_ring stack librte_mempool_stack bonding librte_pmd_bond liquidio librte_pmd_lio sfc librte_pmd_sfc_efx thunderx librte_pmd_thunderx_nicvf vmxnet3 librte_pmd_vmxnet3_uio lib librte_ethtool eal librte_eal librte_ether librte_ethdev To solve this, we can either: 1- do additional fixes of the "dir name -> lib name" conversion in lib.mk for all this list above, as we are doing for eal or ethdev. This looks feasible, but quite ugly. 2- rename all directories to match the libname (ex: drivers/net/null becomes drivers/net/librte_pmd_null). Looks to be a bad idea ;) 3- stop to generate the list of libraries from depdirs: DEPDIRS is kept for directory dependency at build, and the list of libraries is advertised in LDLIBS variable, in each Makefile. My vote would go for option 3.
