Re: [Xen-devel] [PATCH v2 1/5] Remove hardcoded strict -Werror checking

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 20/12/2016 20:06, Doug Goldstein wrote:
> On 12/20/16 1:46 PM, Alistair Francis wrote:
>> Signed-off-by: Alistair Francis <alistair.francis@xxxxxxxxxx>
>> ---
>>  Config.mk                      | 2 +-
>>  tools/blktap2/drivers/Makefile | 1 -
>>  tools/libxl/Makefile           | 2 +-
>>  tools/xentrace/Makefile        | 2 --
>>  4 files changed, 2 insertions(+), 5 deletions(-)
>>
>> diff --git a/Config.mk b/Config.mk
>> index 3ec7367..e3cda81 100644
>> --- a/Config.mk
>> +++ b/Config.mk
>> @@ -34,7 +34,7 @@ CONFIG_$(XEN_OS) := y
>>  SHELL     ?= /bin/sh
>>  
>>  # Tools to run on system hosting the build
>> -HOSTCFLAGS  = -Wall -Werror -Wstrict-prototypes -O2 -fomit-frame-pointer
>> +HOSTCFLAGS  = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
>>  HOSTCFLAGS += -fno-strict-aliasing
>>  
>>  DISTDIR     ?= $(XEN_ROOT)/dist
>> diff --git a/tools/blktap2/drivers/Makefile b/tools/blktap2/drivers/Makefile
>> index 5328c40..7a62a3f 100644
>> --- a/tools/blktap2/drivers/Makefile
>> +++ b/tools/blktap2/drivers/Makefile
>> @@ -9,7 +9,6 @@ QCOW_UTIL  = img2qcow qcow-create qcow2raw
>>  LOCK_UTIL  = lock-util
>>  INST_DIR   = $(sbindir)
>>  
>> -CFLAGS    += -Werror
>>  CFLAGS    += -Wno-unused
>>  CFLAGS    += -fno-strict-aliasing
>>  CFLAGS    += -I$(BLKTAP_ROOT)/include -I$(BLKTAP_ROOT)/drivers
>> diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
>> index 91e2f97..e8a37ef 100644
>> --- a/tools/libxl/Makefile
>> +++ b/tools/libxl/Makefile
>> @@ -11,7 +11,7 @@ MINOR = 0
>>  XLUMAJOR = 4.9
>>  XLUMINOR = 0
>>  
>> -CFLAGS += -Werror -Wno-format-zero-length -Wmissing-declarations \
>> +CFLAGS += -Wno-format-zero-length -Wmissing-declarations \
>>      -Wno-declaration-after-statement -Wformat-nonliteral
>>  CFLAGS += -I. -fPIC
>>  
>> diff --git a/tools/xentrace/Makefile b/tools/xentrace/Makefile
>> index c8c36a8..ac5c534 100644
>> --- a/tools/xentrace/Makefile
>> +++ b/tools/xentrace/Makefile
>> @@ -1,8 +1,6 @@
>>  XEN_ROOT=$(CURDIR)/../..
>>  include $(XEN_ROOT)/tools/Rules.mk
>>  
>> -CFLAGS += -Werror
>> -
>>  CFLAGS += $(CFLAGS_libxenevtchn)
>>  CFLAGS += $(CFLAGS_libxenctrl)
>>  LDLIBS += $(LDLIBS_libxenevtchn)
>>
> Can you pass -Wno-error in EXTRA_CFLAGS from 2/5? Wish I could take
> credit for the idea but it was all Andrew Cooper's.

The point is that, especially with kernel-level development, almost all
warnings are relevant to correctness.  I have only seen 2? false
positives in 5 years, and have lost count of how many issues -Werror has
caught before the code actually got committed.

~Andrew


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