Re: [RFC v3 6/8] build: mark exported symbols

[David Marchand <david.marchand@redhat.com>]

On Thu, Mar 13, 2025 at 6:31 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> On Tue, Mar 11, 2025 at 10:56:04AM +0100, David Marchand wrote:
> > Annotate symbols with newly introduced export macros.
> >
> > For code not compiled by lib/meson.build or drivers/meson.build (like AVX
> > separate libraries, or sources in /base/ drivers), the exported symbols
> > are added in some file listed in the sources so they get caught by
> > lib/meson.build or drivers/meson.build.
> >
> > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > ---
>
> Just checking: for the AVX2 and similar instruction-set-specific functions,
> we don't get errors if those are not present in the actual link phase, e.g.
> when building on non-x86 platforms? We don't need to put an #ifdef around
> the exports?

We are not there yet, but it is likely MSVC linker will complain, indeed.

#ifdef around the exports won't work, we would need a precompiler pass
(and exclude rte_exports.h inclusion).

Another option would be to provide stubs for those symbols when the
additional AVX512 (for example) libraries are not compiled.

But I think the simpler is to let a driver/library provide a set of
sources to parse for exports... maybe via an extra variable?
WDYT?

Something like:

diff --git a/drivers/meson.build b/drivers/meson.build
index 2b0fcd4ef0..6828067fd1 100644
--- a/drivers/meson.build
+++ b/drivers/meson.build
@@ -269,7 +268,7 @@ foreach subpath:subdirs
         endif
         version_map = custom_target(lib_name + '_map',
                 command: [gen_version_map, link_mode,
abi_version_file, '@OUTPUT@', '@INPUT@'],
-                input: sources,
+                input: sources + exported_symbol_sources,
                 output: '_'.join(class, name, 'exports.map'))
         lk_deps = [version_map]
 diff --git a/drivers/net/intel/idpf/idpf_common_rxtx.c
b/drivers/net/intel/idpf/idpf_common_rxtx.c
index 5764bd0e9b..b468e1cd57 100644
--- a/drivers/net/intel/idpf/idpf_common_rxtx.c
+++ b/drivers/net/intel/idpf/idpf_common_rxtx.c
@@ -1647,12 +1647,3 @@ idpf_qc_splitq_rx_vec_setup(struct idpf_rx_queue *rxq)
        rxq->bufq2->ops = &def_rx_ops_vec;
        return idpf_rxq_vec_setup_default(rxq->bufq2);
 }
-
-/* Export all AVX* symbols */
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_recv_pkts_avx2)
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_xmit_pkts_avx2)
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_recv_pkts_avx512)
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_splitq_recv_pkts_avx512)
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_xmit_pkts_avx512)
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_splitq_xmit_pkts_avx512)
-RTE_EXPORT_INTERNAL_SYMBOL(idpf_qc_tx_vec_avx512_setup)
diff --git a/drivers/net/intel/idpf/idpf_common_rxtx_avx2.c
b/drivers/net/intel/idpf/idpf_common_rxtx_avx2.c
index 43a95466ae..3ff70955c8 100644
--- a/drivers/net/intel/idpf/idpf_common_rxtx_avx2.c
+++ b/drivers/net/intel/idpf/idpf_common_rxtx_avx2.c
@@ -473,6 +473,7 @@ _idpf_singleq_recv_raw_pkts_vec_avx2(struct
idpf_rx_queue *rxq, struct rte_mbuf
  * Notice:
  * - nb_pkts < IDPF_DESCS_PER_LOOP, just return no packet
  */
+RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_recv_pkts_avx2)
 uint16_t
 idpf_dp_singleq_recv_pkts_avx2(void *rx_queue, struct rte_mbuf
**rx_pkts, uint16_t nb_pkts)
 {
@@ -682,6 +683,7 @@ idpf_singleq_xmit_fixed_burst_vec_avx2(void
*tx_queue, struct rte_mbuf **tx_pkts
        return nb_pkts;
 }

+RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_xmit_pkts_avx2)
 uint16_t
 idpf_dp_singleq_xmit_pkts_avx2(void *tx_queue, struct rte_mbuf **tx_pkts,
                               uint16_t nb_pkts)
diff --git a/drivers/net/intel/idpf/idpf_common_rxtx_avx512.c
b/drivers/net/intel/idpf/idpf_common_rxtx_avx512.c
index b630d1fcd9..e8bf8149e1 100644
--- a/drivers/net/intel/idpf/idpf_common_rxtx_avx512.c
+++ b/drivers/net/intel/idpf/idpf_common_rxtx_avx512.c
@@ -530,6 +530,7 @@ _idpf_singleq_recv_raw_pkts_avx512(struct
idpf_rx_queue *rxq,
  * Notice:
  * - nb_pkts < IDPF_DESCS_PER_LOOP, just return no packet
  */
+RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_recv_pkts_avx512)
 uint16_t
 idpf_dp_singleq_recv_pkts_avx512(void *rx_queue, struct rte_mbuf **rx_pkts,
                                 uint16_t nb_pkts)
@@ -987,6 +988,7 @@ _idpf_splitq_recv_raw_pkts_avx512(struct idpf_rx_queue *rxq,
 }

 /* only bufq2 can receive pkts */
+RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_splitq_recv_pkts_avx512)
 uint16_t
 idpf_dp_splitq_recv_pkts_avx512(void *rx_queue, struct rte_mbuf **rx_pkts,
                             uint16_t nb_pkts)
@@ -1281,6 +1283,7 @@ idpf_singleq_xmit_pkts_vec_avx512_cmn(void
*tx_queue, struct rte_mbuf **tx_pkts,
        return nb_tx;
 }

+RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_singleq_xmit_pkts_avx512)
 uint16_t
 idpf_dp_singleq_xmit_pkts_avx512(void *tx_queue, struct rte_mbuf **tx_pkts,
                                 uint16_t nb_pkts)
@@ -1584,6 +1587,7 @@ idpf_splitq_xmit_pkts_vec_avx512_cmn(void
*tx_queue, struct rte_mbuf **tx_pkts,
        return nb_tx;
 }

+RTE_EXPORT_INTERNAL_SYMBOL(idpf_dp_splitq_xmit_pkts_avx512)
 uint16_t
 idpf_dp_splitq_xmit_pkts_avx512(void *tx_queue, struct rte_mbuf **tx_pkts,
                                uint16_t nb_pkts)
@@ -1619,6 +1623,7 @@ static const struct idpf_txq_ops avx512_tx_vec_ops = {
        .release_mbufs = idpf_tx_release_mbufs_avx512,
 };

+RTE_EXPORT_INTERNAL_SYMBOL(idpf_qc_tx_vec_avx512_setup)
 int __rte_cold
 idpf_qc_tx_vec_avx512_setup(struct idpf_tx_queue *txq)
 {
diff --git a/drivers/net/intel/idpf/meson.build
b/drivers/net/intel/idpf/meson.build
index 4b272d02b1..47f6f8736e 100644
--- a/drivers/net/intel/idpf/meson.build
+++ b/drivers/net/intel/idpf/meson.build
@@ -25,6 +25,7 @@ if arch_subdir == 'x86' and
dpdk_conf.get('RTE_IOVA_IN_MBUF') == 1
         include_directories: includes,
         c_args: [cflags, cc_avx2_flags])
     objs += idpf_avx2_lib.extract_objects('idpf_common_rxtx_avx2.c')
+    exported_symbol_sources += files('idpf_common_rxtx_avx2.c')

     if cc_has_avx512
         cflags += ['-DCC_AVX512_SUPPORT']
@@ -41,6 +42,7 @@ if arch_subdir == 'x86' and
dpdk_conf.get('RTE_IOVA_IN_MBUF') == 1
                 include_directories: includes,
                 c_args: avx512_args)
         objs +=
idpf_common_avx512_lib.extract_objects('idpf_common_rxtx_avx512.c')
+        exported_symbol_sources += files('idpf_common_rxtx_avx512.c')
     endif
 endif



-- 
David Marchand