================
@@ -44,24 +44,30 @@ void PointerSubChecker::checkPreStmt(const BinaryOperator
*B,
const MemRegion *LR = LV.getAsRegion();
const MemRegion *RR = RV.getAsRegion();
-
- if (!(LR && RR))
- return;
-
- const MemRegion *BaseLR = LR->getBaseRegion();
- const MemRegion *BaseRR = RR->getBaseRegion();
-
- if (BaseLR == BaseRR)
+ if (!LR || !RR)
return;
- // Allow arithmetic on different symbolic regions.
- if (isa<SymbolicRegion>(BaseLR) || isa<SymbolicRegion>(BaseRR))
- return;
+ const auto *ElemLR = dyn_cast<ElementRegion>(LR);
+ const auto *ElemRR = dyn_cast<ElementRegion>(RR);
+ // FIXME: We want to verify that these are elements of an array.
+ // Because behavior of ElementRegion it may be confused with a cast.
+ // There is not a simple way to distinguish it from array element (check the
+ // types?). Because this missing check a warning is missing in the rare case
+ // when two casted pointers to the same region (variable) are subtracted.
----------------
NagyDonat wrote:
If two pointers point to the same variable, it's valid to subtract them.
By the way, it's also valid to declare a `long long` variable, point a `char *`
pointer at it (`char *` may point anywhere) and use it to iterate over the
memory region of the `long long` as if it was a `char[8]`. (By the way in this
case you have `ElementRegion`s and your code behaves correctly.)
https://github.com/llvm/llvm-project/pull/93676
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
