[dpdk-dev] [PATCH v2 1/2] ixgbe: fix build with gcc 4.4

[Thomas Monjalon]

With GCC 4.4.7 from CentOS 6.5, the following errors arise:

lib/librte_pmd_ixgbe/ixgbe_rxtx.c: In function ‘ixgbe_dev_rx_queue_setup’:
lib/librte_pmd_ixgbe/ixgbe_rxtx.c:2509: error: missing initializer
lib/librte_pmd_ixgbe/ixgbe_rxtx.c:2509: error: (near initialization for ‘dev_info.driver_name’)

lib/librte_pmd_ixgbe/ixgbe_rxtx.c: In function ‘ixgbe_set_rsc’:
lib/librte_pmd_ixgbe/ixgbe_rxtx.c:4072: error: missing initializer
lib/librte_pmd_ixgbe/ixgbe_rxtx.c:4072: error: (near initialization for ‘dev_info.driver_name’)

lib/librte_pmd_ixgbe/ixgbe_rxtx.c: In function ‘ixgbe_recv_pkts_lro_single_alloc’:
lib/librte_pmd_ixgbe/ixgbe_rxtx.c:1479: error: ‘next_rsc_entry’ may be used uninitialized in this function
lib/librte_pmd_ixgbe/ixgbe_rxtx.c:1480: error: ‘next_rxe’ may be used uninitialized in this function

The "missing initializer" warning is a GCC bug which seems fixed in 4.7.
The "may be used uninitialized" warning seems to be another GCC bug and is
workarounded with NULL initialization.

Fixes: 8eecb3295aed ("ixgbe: add LRO support")

Signed-off-by: Thomas Monjalon <thomas.monjalon at 6wind.com>
---
changes in v2:
- option -Wno-missing-field-initializers for old GCC instead of code workaround

 lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 4 ++--
 mk/toolchain/gcc/rte.vars.mk      | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
index f1da9ec..6475c44 100644
--- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
+++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
@@ -1476,8 +1476,8 @@ ixgbe_recv_pkts_lro(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts,
 		bool eop;
 		struct ixgbe_rx_entry *rxe;
 		struct ixgbe_rsc_entry *rsc_entry;
-		struct ixgbe_rsc_entry *next_rsc_entry;
-		struct ixgbe_rx_entry *next_rxe;
+		struct ixgbe_rsc_entry *next_rsc_entry = NULL;
+		struct ixgbe_rx_entry *next_rxe = NULL;
 		struct rte_mbuf *first_seg;
 		struct rte_mbuf *rxm;
 		struct rte_mbuf *nmb;
diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
index 88f235c..208cddd 100644
--- a/mk/toolchain/gcc/rte.vars.mk
+++ b/mk/toolchain/gcc/rte.vars.mk
@@ -80,5 +80,10 @@ WERROR_FLAGS += -Wundef -Wwrite-strings
 # process cpu flags
 include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
 
+# workaround GCC bug with warning "missing initializer" for "= {0}"
+ifeq ($(shell test $(GCC_VERSION) -lt 47 && echo 1), 1)
+WERROR_FLAGS += -Wno-missing-field-initializers
+endif
+
 export CC AS AR LD OBJCOPY OBJDUMP STRIP READELF
 export TOOLCHAIN_CFLAGS TOOLCHAIN_LDFLAGS TOOLCHAIN_ASFLAGS
-- 
2.2.2