Re: [dpdk-dev] [PATCH] Make -Werror optional

[Panu Matilainen <pmatilai@redhat.com>]

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 -