[dpdk-dev] Make -Werror optional

On 02/12/2015 02:08 PM, Bruce Richardson wrote:
> On Thu, Feb 12, 2015 at 02:02:19PM +0200, Panu Matilainen wrote:
>> On 02/12/2015 01:25 PM, Bruce Richardson wrote:
>>> On Thu, Feb 12, 2015 at 01:13:22PM +0200, Panu Matilainen wrote:
>>>> This adds new CONFIG_RTE_ERROR_ON_WARNING config option to enable
>>>> fail-on-warning compile behavior, defaulting to off.
>>>>
>>>> Failing build on warnings is a useful developer tool but its bad
>>>> for release tarballs which can and do get built with newer
>>>> compilers than what was used/available during development. Compilers
>>>> routinely add new warnings so code which built silently with cc X
>>>> might no longer do so with X+1. This doesn't make the existing code
>>>> any more buggier and failing the build in this case does not help
>>>> not help improve code quality of an already released version either.
>>>
>>> This can already be achieve by passing EXTRA_CFLAGS='-Wno-error' into the
>>> build command. I don't like changing the default option here. Better to
>>> instead document how to disable the warning flags if necessary.
>>
>> Well, optimally it would only default to off in released versions, which is
>> where the Werror behavior is just annoying without being useful.
>
> This I can agree with.

Ok, would something to this tune be more acceptable?

(non-gcc toolchains are missing and whitespace probably broken due to 
copy-paste, this is not a suggested patch but just an RFC for the approach)


	- Panu -
  

On Thu, Feb 12, 2015 at 03:58:07PM +0200, Panu Matilainen wrote:
> On 02/12/2015 02:08 PM, Bruce Richardson wrote:
> >On Thu, Feb 12, 2015 at 02:02:19PM +0200, Panu Matilainen wrote:
> >>On 02/12/2015 01:25 PM, Bruce Richardson wrote:
> >>>On Thu, Feb 12, 2015 at 01:13:22PM +0200, Panu Matilainen wrote:
> >>>>This adds new CONFIG_RTE_ERROR_ON_WARNING config option to enable
> >>>>fail-on-warning compile behavior, defaulting to off.
> >>>>
> >>>>Failing build on warnings is a useful developer tool but its bad
> >>>>for release tarballs which can and do get built with newer
> >>>>compilers than what was used/available during development. Compilers
> >>>>routinely add new warnings so code which built silently with cc X
> >>>>might no longer do so with X+1. This doesn't make the existing code
> >>>>any more buggier and failing the build in this case does not help
> >>>>not help improve code quality of an already released version either.
> >>>
> >>>This can already be achieve by passing EXTRA_CFLAGS='-Wno-error' into the
> >>>build command. I don't like changing the default option here. Better to
> >>>instead document how to disable the warning flags if necessary.
> >>
> >>Well, optimally it would only default to off in released versions, which is
> >>where the Werror behavior is just annoying without being useful.
> >
> >This I can agree with.
> 
> Ok, would something to this tune be more acceptable?
> 
> diff --git a/mk/rte.vars.mk b/mk/rte.vars.mk
> index d5b36be..2ad969b 100644
> --- a/mk/rte.vars.mk
> +++ b/mk/rte.vars.mk
> @@ -71,6 +71,10 @@ ifneq ($(BUILDING_RTE_SDK),)
>    ifeq ($(RTE_BUILD_COMBINE_LIBS),)
>      RTE_BUILD_COMBINE_LIBS := n
>    endif
> +  # see if we're building from git
> +  ifneq ($(wildcard $(RTE_SDK)/.git),)
> +    DEVEL_BUILD := y
> +  endif
>  endif
> 
>  RTE_LIBNAME := $(CONFIG_RTE_LIBNAME:"%"=%)
> diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
> index 88f235c..a14ae44 100644
> --- a/mk/toolchain/gcc/rte.vars.mk
> +++ b/mk/toolchain/gcc/rte.vars.mk
> @@ -71,12 +71,16 @@ ifeq (,$(findstring -O0,$(EXTRA_CFLAGS)))
>  endif
>  endif
> 
> -WERROR_FLAGS := -W -Wall -Werror -Wstrict-prototypes -Wmissing-prototypes
> +WERROR_FLAGS := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
>  WERROR_FLAGS += -Wmissing-declarations -Wold-style-definition
> -Wpointer-arith
>  WERROR_FLAGS += -Wcast-align -Wnested-externs -Wcast-qual
>  WERROR_FLAGS += -Wformat-nonliteral -Wformat-security
>  WERROR_FLAGS += -Wundef -Wwrite-strings
> 
> +ifeq ($(DEVEL_BUILD),y)
> +WERROR_FLAGS += -Werror
> +endif
> +
>  # process cpu flags
>  include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
> 
> (non-gcc toolchains are missing and whitespace probably broken due to
> copy-paste, this is not a suggested patch but just an RFC for the approach)
> 
> 
> 	- Panu -
> 
Looks ok to me.
/Bruce
  

2015-02-12 15:58, Panu Matilainen:
> +  # see if we're building from git
> +  ifneq ($(wildcard $(RTE_SDK)/.git),)
> +    DEVEL_BUILD := y
> +  endif

Yes it allows to force DEVEL_BUILD to any value on command line.
But please use RTE_ prefix.