On 02/12/2015 04:38 PM, Stephen Hemminger wrote:
> On Thu, 12 Feb 2015 13:13:22 +0200
> Panu Matilainen <pmatilai at redhat.com> 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.
>> ---
>> config/common_bsdapp | 1 +
>> config/common_linuxapp | 1 +
>> mk/toolchain/clang/rte.vars.mk | 5 ++++-
>> mk/toolchain/gcc/rte.vars.mk | 5 ++++-
>> mk/toolchain/icc/rte.vars.mk | 6 +++++-
>> 5 files changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/config/common_bsdapp b/config/common_bsdapp
>> index 57bacb8..a5687b3 100644
>> --- a/config/common_bsdapp
>> +++ b/config/common_bsdapp
>> @@ -362,6 +362,7 @@ CONFIG_RTE_KNI_VHOST_DEBUG_TX=n
>> # Enable warning directives
>> #
>> CONFIG_RTE_INSECURE_FUNCTION_WARNING=n
>> +CONFIG_RTE_ERROR_ON_WARNING=n
>>
>> #
>> # Compile the test application
>> diff --git a/config/common_linuxapp b/config/common_linuxapp
>> index d428f84..0762f99 100644
>> --- a/config/common_linuxapp
>> +++ b/config/common_linuxapp
>> @@ -383,6 +383,7 @@ CONFIG_RTE_LIBRTE_XEN_DOM0=n
>> # Enable warning directives
>> #
>> CONFIG_RTE_INSECURE_FUNCTION_WARNING=n
>> +CONFIG_RTE_ERROR_ON_WARNING=n
>>
>> #
>> # Compile the test application
>> diff --git a/mk/toolchain/clang/rte.vars.mk b/mk/toolchain/clang/rte.vars.mk
>> index 40cb389..12726e7 100644
>> --- a/mk/toolchain/clang/rte.vars.mk
>> +++ b/mk/toolchain/clang/rte.vars.mk
>> @@ -63,11 +63,14 @@ TOOLCHAIN_ASFLAGS =
>> TOOLCHAIN_CFLAGS =
>> TOOLCHAIN_LDFLAGS =
>>
>> -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 += -Wnested-externs -Wcast-qual
>> WERROR_FLAGS += -Wformat-nonliteral -Wformat-security
>> WERROR_FLAGS += -Wundef -Wwrite-strings
>> +ifeq ($(CONFIG_RTE_ERROR_ON_WARNING),y)
>> +WERROR_FLAGS += -Werror
>> +endif
>>
>> # process cpu flags
>> include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
>> diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
>> index 88f235c..bbd3c85 100644
>> --- a/mk/toolchain/gcc/rte.vars.mk
>> +++ b/mk/toolchain/gcc/rte.vars.mk
>> @@ -71,11 +71,14 @@ 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 ($(CONFIG_RTE_ERROR_ON_WARNING),y)
>> +WERROR_FLAGS += -Werror
>> +endif
>>
>> # process cpu flags
>> include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
>> diff --git a/mk/toolchain/icc/rte.vars.mk b/mk/toolchain/icc/rte.vars.mk
>> index e39d710..652cca8 100644
>> --- a/mk/toolchain/icc/rte.vars.mk
>> +++ b/mk/toolchain/icc/rte.vars.mk
>> @@ -69,8 +69,12 @@ TOOLCHAIN_ASFLAGS =
>> # error #13368: loop was not vectorized with "vector always assert"
>> # error #15527: loop was not vectorized: function call to fprintf cannot
>> be vectorize
>> # was declared "deprecated"
>> -WERROR_FLAGS := -Wall -Werror-all -w2 -diag-disable 271 -diag-warning 1478
>> +WERROR_FLAGS := -Wall -w2 -diag-disable 271 -diag-warning 1478
>> WERROR_FLAGS += -diag-disable 13368 -diag-disable 15527
>> +ifeq ($(CONFIG_RTE_ERROR_ON_WARNING),y)
>> +WERROR_FLAGS += -Werror-all
>> +endif
>> +
>>
>> # process cpu flags
>> include $(RTE_SDK)/mk/toolchain/$(RTE_TOOLCHAIN)/rte.toolchain-compat.mk
>
> The -Werror is a real feature. Having dealt with legacy code where
> there are lots of bugs which were already warnings being ignored, having
> a big hard stop when errors are found is really good.
>
> The default should be on but I understand why you may want to turn it
> off, but it should require some effort to do.
I wholeheartedly agree with all that, when applied the developers of the
codebase. I spent the last 7+ years of my life working on a piece of
software that emitted well over six hundred "harmless" warnings on build
when I started with it, trust me I have very little tolerance for
introducing new compiler warnings.
But placing that burden to users trying to compile a released version of
the software does good to nobody.
- Panu -
