[clang] [SSAF][UnsafeBufferAnalysis] Filter out type-constrained pointers from reachable unsafe pointers (PR #209354)

[Balázs Benics via cfe-commits]

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@@ -233,6 +237,65 @@ class UnsafeBufferReachableAnalysis
 
       updateReachablesWithOutgoings(Node, Worklist);
     }
+  }
+
+  /// \return a lazy range over the pointers in \p UnsafePtrs whose entity is
+  /// NOT type-constrained (per \p TypeConstraints).
+  auto filterNonConstrainedPointers(
+      const EntityPointerLevelSet &UnsafePtrs,
+      const TypeConstrainedPointersAnalysisResult &TypeConstraints) {
+    return llvm::make_filter_range(
+        UnsafePtrs, [&TypeConstraints](const EntityPointerLevel &EPL) {
+          return !TypeConstraints.contains(EPL.getEntity());
+        });
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steakhal wrote:

I've not checked the call-sites but this is potentially dangerous.
If anyone would pass a temporary `TypeConstraints` object, then the view we return would dangle after the semicolon of the call-site.

https://github.com/llvm/llvm-project/pull/209354