[clang] [analyzer] Suppress out of bounds reports after weak loop assumptions (PR #109804)

[Donát Nagy via cfe-commits]

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@@ -212,6 +212,25 @@ typedef llvm::ImmutableMap<const LocationContext *, unsigned>
 REGISTER_TRAIT_WITH_PROGRAMSTATE(PendingArrayDestruction,
                                  PendingArrayDestructionMap)
 
+// This trait is used to heuristically filter out results produced from
+// execution paths that took "weak" assumptions within a loop.
+REGISTER_TRAIT_WITH_PROGRAMSTATE(SeenWeakLoopAssumption, bool)
+
+ProgramStateRef clang::ento::recordWeakLoopAssumption(ProgramStateRef State) {
+  return State->set<SeenWeakLoopAssumption>(true);
+}
+
+bool clang::ento::seenWeakLoopAssumption(ProgramStateRef State) {
+  return State->get<SeenWeakLoopAssumption>();
+}
+
+// This trait points to the last expression (logical operator) where an eager
+// assumption introduced a state split (i.e. both cases were feasible). This is
+// used by the WeakLoopAssumption heuristic to find situations where the an
+// eager assumption introduces a state split within the evaluation of a loop
+// condition.
+REGISTER_TRAIT_WITH_PROGRAMSTATE(LastEagerlyAssumeAssumptionAt, const Expr *)
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NagyDonat wrote:

I tried to emphasize that I'm only marking the `EagerlyAssume` checks that _did assume something new_ (i.e. they introduce a state split). I'll probably rename this to `LastEagerAssumptionStateSplitAt` or something similar.

https://github.com/llvm/llvm-project/pull/109804