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. > Oh my understanding of the consensus was to move flex array related diagnosis > from -Warray-bounds to -Wstring-flex-arrays as Qing has done. If only the > former exists then instead of removing the flex array related statement in the > documentation as Richard suggested, we need to enhance it to say that > behaviour of -Warray-bounds will depend on -fstrict-flex-arrays. > > -Warray-bounds does diagnosis beyond just flexible arrays, in case that's the > confusion. 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)
