From: David Marchand <david.marchand@redhat.com>
To: Reshma Pattan <reshma.pattan@intel.com>
Cc: dev <dev@dpdk.org>, Bruce Richardson <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH v2] mk: report address of packed member as warning
Date: Thu, 2 May 2019 16:24:37 +0200 [thread overview]
Message-ID: <CAJFAV8xoYMUWDCEqKHAggPixF4XAQQ8Xwca7wNMnT-xVAw433A@mail.gmail.com> (raw)
In-Reply-To: <20190502141316.25907-1-reshma.pattan@intel.com>
On Thu, May 2, 2019 at 4:13 PM Reshma Pattan <reshma.pattan@intel.com>
wrote:
> gcc 9 on Fedora 30 gives an error
> "taking address of packed member may result in an
> unaligned pointer value" for -Waddress-of-packed-member.
>
> Report it as warning instead of error to fix the build.
>
> Snippet of build before fix
> ...lib/librte_eal/linux/eal/eal_memalloc.c: In function ‘alloc_seg_walk’:
> ...lib/librte_eal/linux/eal/eal_memalloc.c:768:12: error: taking address
> of packed member of ‘struct rte_mem_config’ may result in an unaligned
> pointer value [-Werror=address-of-packed-member]
> 768 | cur_msl = &mcfg->memsegs[msl_idx];
> | ^~~~~~~~~~~~~~~~~~~~~~~
>
> Snippet of build after fix
> ..lib/librte_eal/linux/eal/eal_memory.c: In function ‘remap_segment’:
> ..lib/librte_eal/linux/eal/eal_memory.c:685:9: warning: taking address
> of packed member of ‘struct rte_mem_config’ may result in an unaligned
> pointer value [-Waddress-of-packed-member]
> 685 | msl = &mcfg->memsegs[msl_idx];
>
> Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
> ---
> mk/toolchain/gcc/rte.vars.mk | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
> index d8b99faf6..61032bbbc 100644
> --- a/mk/toolchain/gcc/rte.vars.mk
> +++ b/mk/toolchain/gcc/rte.vars.mk
> @@ -87,5 +87,9 @@ WERROR_FLAGS += -Wimplicit-fallthrough=2
> WERROR_FLAGS += -Wno-format-truncation
> endif
>
> +#Report "taking address of packed member may result
> +#in an unaligned pointer value" issues as warnings.
> +WERROR_FLAGS += -Wno-error=address-of-packed-member
> +
> export CC AS AR LD OBJCOPY OBJDUMP STRIP READELF
> export TOOLCHAIN_CFLAGS TOOLCHAIN_LDFLAGS TOOLCHAIN_ASFLAGS
> --
> 2.21.0
>
>
No, you can't do this unconditionally.
Looked at clang (in make build system) and meson (globally) and those
completely disable the warning.
$ git grep address-of-packed-member origin/master --
origin/master:config/meson.build: '-Wno-address-of-packed-member'
origin/master:mk/toolchain/clang/rte.vars.mk:WERROR_FLAGS +=
-Wno-address-of-packed-member
It should be something like (untested):
@@ -87,5 +87,10 @@ WERROR_FLAGS += -Wimplicit-fallthrough=2
WERROR_FLAGS += -Wno-format-truncation
endif
+# disable packed member unalign warnings
+ifeq ($(shell test $(GCC_VERSION) -ge 90 && echo 1), 1)
+WERROR_FLAGS += -Wno-address-of-packed-member
+endif
+
export CC AS AR LD OBJCOPY OBJDUMP STRIP READELF
export TOOLCHAIN_CFLAGS TOOLCHAIN_LDFLAGS TOOLCHAIN_ASFLAGS
--
David Marchand
next prev parent reply other threads:[~2019-05-02 14:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-02 9:33 [dpdk-dev] [PATCH] mk: disable warning with gcc 9 on Fedora 30 Reshma Pattan
2019-05-02 9:33 ` Reshma Pattan
2019-05-02 10:07 ` David Marchand
2019-05-02 10:07 ` David Marchand
2019-05-02 13:26 ` Bruce Richardson
2019-05-02 13:26 ` Bruce Richardson
2019-05-02 13:30 ` David Marchand
2019-05-02 13:30 ` David Marchand
2019-05-02 13:35 ` Pattan, Reshma
2019-05-02 13:35 ` Pattan, Reshma
2019-05-02 14:13 ` [dpdk-dev] [PATCH v2] mk: report address of packed member as warning Reshma Pattan
2019-05-02 14:13 ` Reshma Pattan
2019-05-02 14:24 ` David Marchand [this message]
2019-05-02 14:24 ` David Marchand
2019-05-02 14:41 ` Bruce Richardson
2019-05-02 14:41 ` Bruce Richardson
2019-05-02 14:48 ` David Marchand
2019-05-02 14:48 ` David Marchand
2019-05-02 15:53 ` Burakov, Anatoly
2019-05-02 15:53 ` Burakov, Anatoly
2019-05-02 18:54 ` Stephen Hemminger
2019-05-02 18:54 ` Stephen Hemminger
2019-05-03 7:56 ` Burakov, Anatoly
2019-05-03 7:56 ` Burakov, Anatoly
2019-05-02 15:00 ` [dpdk-dev] [PATCH] mk: disable warning with gcc 9 on Fedora 30 David Marchand
2019-05-02 15:00 ` David Marchand
2019-05-02 15:56 ` Thomas Monjalon
2019-05-02 15:56 ` Thomas Monjalon
2019-05-03 16:01 ` Jerin Jacob Kollanukkaran
2019-05-03 16:01 ` Jerin Jacob Kollanukkaran
2019-05-03 16:25 ` Bruce Richardson
2019-05-03 16:25 ` Bruce Richardson
2019-05-03 16:28 ` Richardson, Bruce
2019-05-03 16:28 ` Richardson, Bruce
2019-05-03 17:24 ` [dpdk-dev] [EXT] " Jerin Jacob Kollanukkaran
2019-05-03 17:24 ` Jerin Jacob Kollanukkaran
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