On Fri, 2 Dec 2022, Qing Zhao wrote: > > > > On Dec 2, 2022, at 2:20 AM, Richard Biener <rguent...@suse.de> wrote: > > > > On Fri, 2 Dec 2022, Richard Biener wrote: > > > >> On Thu, 1 Dec 2022, Siddhesh Poyarekar wrote: > >> > >>> 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 to > >>>>> 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=LEVEL'. > >>>>> > >>>>> This option is effective only when LEVEL is bigger than 0. > >>>>> Otherwise, it will be ignored with a warning. > >>>>> > >>>>> when LEVEL=1, 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. > >>>>> > >>>>> when LEVEL=2, in addition to LEVEL=1, additional warnings will be > >>>>> issued for a trailing one-element array reference of a structure if > >>>>> the array is referenced as a flexible array member. > >>>>> > >>>>> when LEVEL=3, in addition to LEVEL=2, additional warnings will be > >>>>> issued for a trailing zero-length array reference of a structure if > >>>>> the array is referenced as a flexible array member. > >>>>> > >>>>> At the same time, -Warray-bounds is updated: > >>>> > >>>> Why is there both -Wstrict-flex-arrays and -Warray-bounds? I thought > >>>> only the latter was going to exist? > >> > >> Sorry for appearantly not being clear - I was requesting > >> -Wstrict-flex-arrays to be dropped and instead adjusting -Warray-bounds > >> to adhere to -fstrict-flex-arrays in both =1 and =2 where then =2 > >> would only add the intermediate pointer results verification. > >> > >> 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. > > > > Btw, your patch seems to implement the above plus adds > > -Wstrict-flex-arrays. It seems it could be split into two, doing > > the -Warray-bounds adjustment as first and the -Wstrict-flex-arrays > > addition as second. > > Yes, implementation should be very easy to be adjusted to drop the new > -Wstrict-flex-arrays option. > But I still feel the new -Wstrict-flex-arrays option is good to add.
Can you split the patch and re-post? I'll quickly approve the first part and will think harder on the second. Thanks, Richard. > Qing > > We do all seem to agree on the first so it's easy > > to go forward with that? > > > > Thanks, > > Richard. > > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; HRB 36809 (AG Nuernberg)
