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Thread-Topic: [V2][PATCH 1/1] Add a new warning option -Wstrict-flex-arrays. 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charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: CH2PR10MB4344.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2b6b6cbc-8cfc-4974-d6c3-08dad473919e X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Dec 2022 14:43:25.5154 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: ScgTLKP4viYwzGnq5XaBX0W8XrmNtpYuwKyI+E0oi3P5z9rByu7zFyijIuDuIUD46pum/jI8qZaojkswMht+ZA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR10MB5168 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-02_07,2022-12-01_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 suspectscore=0 bulkscore=0 adultscore=0 mlxlogscore=896 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2212020114 X-Proofpoint-GUID: QZdm42tbMMNcqdgMlMlzdwPh7ZOd_SEJ X-Proofpoint-ORIG-GUID: QZdm42tbMMNcqdgMlMlzdwPh7ZOd_SEJ X-Spam-Status: No, score=-5.3 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > On Dec 2, 2022, at 2:20 AM, Richard Biener wrote: >=20 > On Fri, 2 Dec 2022, Richard Biener wrote: >=20 >> On Thu, 1 Dec 2022, Siddhesh Poyarekar wrote: >>=20 >>> On 2022-12-01 11:42, Kees Cook wrote: >>>> On Wed, Nov 30, 2022 at 02:25:56PM +0000, Qing Zhao wrote: >>>>> '-Wstrict-flex-arrays' >>>>> Warn about inproper usages of flexible array members according t= o >>>>> the LEVEL of the 'strict_flex_array (LEVEL)' attribute attached = to >>>>> the trailing array field of a structure if it's available, >>>>> otherwise according to the LEVEL of the option >>>>> '-fstrict-flex-arrays=3DLEVEL'. >>>>>=20 >>>>> This option is effective only when LEVEL is bigger than 0. >>>>> Otherwise, it will be ignored with a warning. >>>>>=20 >>>>> when LEVEL=3D1, warnings will be issued for a trailing array >>>>> reference of a structure that have 2 or more elements if the >>>>> trailing array is referenced as a flexible array member. >>>>>=20 >>>>> when LEVEL=3D2, in addition to LEVEL=3D1, additional warnings wi= ll be >>>>> issued for a trailing one-element array reference of a structure= if >>>>> the array is referenced as a flexible array member. >>>>>=20 >>>>> when LEVEL=3D3, in addition to LEVEL=3D2, additional warnings wi= ll be >>>>> issued for a trailing zero-length array reference of a structure= if >>>>> the array is referenced as a flexible array member. >>>>>=20 >>>>> At the same time, -Warray-bounds is updated: >>>>=20 >>>> Why is there both -Wstrict-flex-arrays and -Warray-bounds? I thought >>>> only the latter was going to exist? >>=20 >> Sorry for appearantly not being clear - I was requesting=20 >> -Wstrict-flex-arrays to be dropped and instead adjusting -Warray-bounds >> to adhere to -fstrict-flex-arrays in both =3D1 and =3D2 where then =3D2 >> would only add the intermediate pointer results verification. >>=20 >> I think that's reasonable if documented since the default behavior >> with -Wall will not change then unless the -fstrict-flex-arrays >> default is altered. >=20 > Btw, your patch seems to implement the above plus adds=20 > -Wstrict-flex-arrays. It seems it could be split into two, doing > the -Warray-bounds adjustment as first and the -Wstrict-flex-arrays=20 > addition as second. Yes, implementation should be very easy to be adjusted to drop the new -Wst= rict-flex-arrays option. But I still feel the new -Wstrict-flex-arrays option is good to add. Qing > We do all seem to agree on the first so it's easy > to go forward with that? >=20 > Thanks, > Richard.