From: Thomas Monjalon <firstname.lastname@example.org> To: "Phil Yang (Arm Technology China)" <Phil.Yang@arm.com> Cc: email@example.com, Bruce Richardson <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, "email@example.com" <firstname.lastname@example.org>, Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>, "Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>, "Joyce Kong (Arm Technology China)" <Joyce.Kong@arm.com>, nd <email@example.com>, "firstname.lastname@example.org" <email@example.com> Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH 1/2] mk: fix unsupported flag error on armhf architercture Date: Tue, 26 Nov 2019 18:01:38 +0100 Message-ID: <5285313.iaM3IdUqkp@xps> (raw) In-Reply-To: <VE1PR08MB464033DA8BABF30633D41653E9770@VE1PR08MB4640.eurprd08.prod.outlook.com> 12/11/2019 07:40, Phil Yang (Arm Technology China): > > -----Original Message----- > > From: Thomas Monjalon <firstname.lastname@example.org> > > Sent: Tuesday, November 12, 2019 2:03 PM > > To: Phil Yang (Arm Technology China) <Phil.Yang@arm.com> > > Cc: Bruce Richardson <email@example.com>; firstname.lastname@example.org; > > email@example.com; firstname.lastname@example.org; Honnappa Nagarahalli > > <Honnappa.Nagarahalli@arm.com>; Gavin Hu (Arm Technology China) > > <Gavin.Hu@arm.com>; Joyce Kong (Arm Technology China) > > <Joyce.Kong@arm.com>; nd <email@example.com>; firstname.lastname@example.org > > Subject: Re: [dpdk-dev] [PATCH 1/2] mk: fix unsupported flag error on armhf > > architercture > > > > 12/11/2019 06:25, Phil Yang (Arm Technology China): > > > From: Bruce Richardson <email@example.com> > > > > On Mon, Nov 11, 2019 at 06:34:20PM +0800, Phil Yang wrote: > > > > > The older version (e.g. version 7.4.0 ) of GNU C compiler for the armhf > > > > > architecture doesn't support the flag '-Wno-address-of-packed- > > member', > > > > > so remove this flag for aarch32. > > > > > > > > > > Fixes: a385972c3675 ("mk: disable warning for packed member pointer") > > > > > Cc: firstname.lastname@example.org > > > > > > > > > > Signed-off-by: Phil Yang <email@example.com> > > > > > Reviewed-by: Gavin Hu <firstname.lastname@example.org> > > > > > Tested-by: Joyce Kong <email@example.com> > > > > > > > > > > --- > > > > > mk/toolchain/gcc/rte.vars.mk | 2 ++ > > > > > 1 file changed, 2 insertions(+) > > > > > > > > > > diff --git a/mk/toolchain/gcc/rte.vars.mk > > b/mk/toolchain/gcc/rte.vars.mk > > > > > index 9fc7041..ec0cbbf 100644 > > > > > --- a/mk/toolchain/gcc/rte.vars.mk > > > > > +++ b/mk/toolchain/gcc/rte.vars.mk > > > > > @@ -100,7 +100,9 @@ WERROR_FLAGS += -Wno-format-truncation > > > > > endif > > > > > > > > > > # disable packed member unalign warnings > > > > > +ifneq ($(CONFIG_RTE_ARCH_ARM), y) > > > > > WERROR_FLAGS += -Wno-address-of-packed-member > > > > > +endif > > > > > > > > > You don't need to do this, as gcc will not complain about this unknown > > flag > > > > unless you have other issues in your code. I think it's better to keep > > the > > > > code clean in this case, otherwise we'll have the code littered with > > > > conditionals for various flags. > > > > > > > > /Bruce > > > > > > > >  https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html > > > > "When an unrecognized warning option is requested (e.g., > > > > -Wunknown-warning), GCC emits a diagnostic stating that the option is > > not > > > > recognized. However, if the -Wno- form is used, the behavior is slightly > > > > different: no diagnostic is produced for -Wno-unknown-warning unless > > other > > > > diagnostics are being produced. This allows the use of new -Wno- options > > > > with old compilers, but if something goes wrong, the compiler warns that > > an > > > > unrecognized option is present." > > > > > > Thanks, Bruce. > > > > > > There are thousands of warnings with alignment when compiling for > > ARMv7 (ARMv7 supports unaligned memory access). > > > Without this new flag, the build system works fine for ARMv7. So I add this > > conditional for ARMv7 only. > > > I agree with you we should clean up the code, but it needs a lot of effort to > > achieve that. > > > This patch is going to make the ARMv7 target build successfully during this > > period. > > > > I would go the opposite direction. > > I think we should remove all warnings disablement like "-Wno-something", > > and clean the code. > > Thanks, Thomas. > > I think it is a compiler issue rather than a code defect in this case, as It cannot recognize the '-Waddress-of-packed-member' flag. > "arm-linux-gnueabihf-gcc: error: unrecognized command line option '-Waddress-of-packed-member'" > > > > > If you want to allow building ARMv7, you can just allow warnings as not > > errors. > > So we will still see something is wrong but it won't prevent from building. > > Yes. We did this already, all the alignment issues are emitted as warnings on ARMv7. > Please see these two commits: > 79fa5c2a9992 ("mk: ignore alignment errors for ARMv7") > 6433c19105e8 ("mk: generalize strict alignment warning handling") I don't know what to do with this patch. I think it is not how it should work, but you say your compiler has a real bug. Can you confirm which compiler is it? Does it prevent to compile even with -Wno-error ? Any other opinion?
next prev parent reply other threads:[~2019-11-26 17:01 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-11 10:34 [dpdk-stable] " Phil Yang 2019-11-11 10:34 ` [dpdk-stable] [PATCH 2/2] doc: add aarch32 build guidance Phil Yang 2020-05-24 21:21 ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon 2020-05-25 3:20 ` Phil Yang 2020-05-27 8:28 ` Ruifeng Wang 2020-07-02 5:37 ` Phil Yang 2020-07-02 8:01 ` Jerin Jacob 2019-11-11 10:47 ` [dpdk-stable] [dpdk-dev] [PATCH 1/2] mk: fix unsupported flag error on armhf architercture Bruce Richardson 2019-11-12 5:25 ` Phil Yang (Arm Technology China) 2019-11-12 6:03 ` Thomas Monjalon 2019-11-12 6:40 ` Phil Yang (Arm Technology China) 2019-11-26 17:01 ` Thomas Monjalon [this message] 2019-11-27 8:09 ` Phil Yang (Arm Technology China) 2019-11-27 9:29 ` Bruce Richardson 2019-11-27 10:00 ` Phil Yang (Arm Technology China) 2019-11-27 10:32 ` Thomas Monjalon
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