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

Message ID	1429130956-17828-1-git-send-email-thomas.monjalon@6wind.com (mailing list archive)
State	Superseded, archived
Headers	From: Thomas Monjalon <thomas.monjalon@6wind.com> To: dev@dpdk.org Date: Wed, 15 Apr 2015 22:49:15 +0200 Message-Id: <1429130956-17828-1-git-send-email-thomas.monjalon@6wind.com> In-Reply-To: <1958525.YbKd0lDtje@xps13> References: <1958525.YbKd0lDtje@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH v2 1/2] ixgbe: fix build with gcc 4.4 Precedence: list Errors-To: dev-bounces@dpdk.org Sender: "dev" <dev-bounces@dpdk.org>

Message ID

1429130956-17828-1-git-send-email-thomas.monjalon@6wind.com (mailing list archive)

State

Superseded, archived

Headers

From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: dev@dpdk.org
Date: Wed, 15 Apr 2015 22:49:15 +0200
Message-Id: <1429130956-17828-1-git-send-email-thomas.monjalon@6wind.com>
In-Reply-To: <1958525.YbKd0lDtje@xps13>
References: <1958525.YbKd0lDtje@xps13>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Subject: [dpdk-dev] [PATCH v2 1/2] ixgbe: fix build with gcc 4.4
Precedence: list
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

Commit Message

Thomas Monjalon April 15, 2015, 8:49 p.m. UTC

  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@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(-)

Comments

Zhang, Helin April 16, 2015, 7:26 a.m. UTC | #1

> -----Original Message-----

> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]

> Sent: Thursday, April 16, 2015 4:49 AM

> To: dev@dpdk.org

> Cc: Vlad Zolotarov; Ananyev, Konstantin; Zhang, Helin

> Subject: [PATCH v2 1/2] ixgbe: fix build with gcc 4.4

> 

> 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@6wind.com>

Acked-by: Helin Zhang <helin.zhang@intel.com>

Vladislav Zolotarov April 16, 2015, 9:14 a.m. UTC | #2

On 04/15/15 23:49, Thomas Monjalon wrote:
> 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@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;

-Wno-maybe-uninitialized ?

>   		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

Thomas Monjalon April 16, 2015, 9:18 a.m. UTC | #3

2015-04-16 12:14, Vlad Zolotarov:
> On 04/15/15 23:49, Thomas Monjalon wrote:
> > The "may be used uninitialized" warning seems to be another GCC bug and is
> > workarounded with NULL initialization.
> > --- 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;
> 
> -Wno-maybe-uninitialized ?

I prefer avoiding this flag for 2 reasons:
	- It's not supported in every GCC versions (need special handling)
	- NULL assigment doesn't hurt

Vladislav Zolotarov April 16, 2015, 9:35 a.m. UTC | #4

On 04/16/15 12:18, Thomas Monjalon wrote:
> 2015-04-16 12:14, Vlad Zolotarov:
>> On 04/15/15 23:49, Thomas Monjalon wrote:
>>> The "may be used uninitialized" warning seems to be another GCC bug and is
>>> workarounded with NULL initialization.
>>> --- 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;
>> -Wno-maybe-uninitialized ?
> I prefer avoiding this flag for 2 reasons:
> 	- It's not supported in every GCC versions (need special handling)

Is it supported for 4.4? U don't have to support all ever existed gcc 
versions. ;)

> 	- NULL assigment doesn't hurt

Right, but still it's ugly since it's clear that it's a workaround - 
right above the patched ones there are variables that are not 
initialized and this discloses the workaround... ;)

>

diff mbox

Patch

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