[clang] [analyzer] Switch to PostStmt callbacks in ArrayBoundV2 (PR #72107)

[Balázs Kéri via cfe-commits]

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@@ -350,17 +383,38 @@ void ArrayBoundCheckerV2::checkLocation(SVal Location, bool IsLoad,
     if (ExceedsUpperBound) {
       if (!WithinUpperBound) {
         // We know that the index definitely exceeds the upper bound.
-        std::string RegName = getRegionName(Reg);
-        std::string Msg = getExceedsMsg(C.getASTContext(), RegName, ByteOffset,
-                                        *KnownSize, Location);
-        reportOOB(C, ExceedsUpperBound, OOB_Exceeds, ByteOffset, RegName, Msg);
+        if (isa<ArraySubscriptExpr>(E) && isInAddressOf(E, C.getASTContext())) {
+          // ...but this is within an addressof expression, so we need to check
+          // for the exceptional case that `&array[size]` is valid.
+          auto [EqualsToThreshold, NotEqualToThreshold] =
+              compareValueToThreshold(ExceedsUpperBound, ByteOffset, *KnownSize,
+                                      SVB, /*CheckEquality=*/true);
+          if (EqualsToThreshold && !NotEqualToThreshold) {
+            // We are definitely in the exceptional case, so return early
+            // instead of reporting a bug.
+            C.addTransition(EqualsToThreshold);
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balazske wrote:

Is this transition needed? This checker should not add assumptions to the state, only check for conditions and add only error transitions. `EqualsToThreshold` probably does not contain new information compared to `State`.

https://github.com/llvm/llvm-project/pull/72107