On Tue, Jul 6, 2021 at 5:47 PM Martin Sebor via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > Ping: https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573349.html
+ if (TREE_CODE (axstype) != UNION_TYPE) what about QUAL_UNION_TYPE? (why constrain union type accesses here - note you don't seem to constrain accesses of union members here) + if (tree access_size = TYPE_SIZE_UNIT (axstype)) + /* The byte size of the array has already been determined above + based on a pointer ARG. Set ELTSIZE to the size of the type + it points to and REFTYPE to the array with the size, rounded + down as necessary. */ + if (POINTER_TYPE_P (reftype)) + reftype = TREE_TYPE (reftype); + if (TREE_CODE (reftype) == ARRAY_TYPE) + reftype = TREE_TYPE (reftype); + if (tree refsize = TYPE_SIZE_UNIT (reftype)) + if (TREE_CODE (refsize) == INTEGER_CST) + eltsize = wi::to_offset (refsize); probably pre-existing but the pointer indirection is definitely confusing me again and again given the variable is named 'reftype' - obviously an access to a pointer does not have any element size. Possibly the paths arriving here ensure somehow that the only case is when reftype is not the access type but a pointer to the accessed memory. "jump-threading" the source might help me avoiding to trip over this again and again ... The patch removes a lot of odd code, I like that. You know this code best and it's hard to spot errors. So OK, you'll deal with the fallout. Thanks, Richard. > On 6/28/21 1:33 PM, Martin Sebor wrote: > > Ping: https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573349.html > > > > On 6/21/21 4:25 PM, Martin Sebor wrote: > >> -Warray-bounds relies on similar logic as -Wstringop-overflow et al., > >> but using its own algorithm, including its own bugs such as PR 100137. > >> The attached patch takes the first step toward unifying the logic > >> between the warnings. It changes a subset of -Warray-bounds to call > >> compute_objsize() to detect out-of-bounds indices. Besides fixing > >> the bug this also nicely simplifies the code and improves > >> the consistency between the informational messages printed by both > >> classes of warnings. > >> > >> The changes to the test suite are extensive mainly because of > >> the different format of the diagnostics resulting from slightly > >> tighter bounds of offsets computed by the new algorithm, and in > >> smaller part because the change lets -Warray-bounds diagnose some > >> problems it previously missed due to the limitations of its own > >> solution. > >> > >> The false positive reported in PR 100137 is a 10/11/12 regression > >> but this change is too intrusive to backport. I have a smaller > >> and more targeted patch I plan to backport in its stead. > >> > >> Tested on x86_64-linux. > >> > >> Martin > > >
