[clang] [analyzer] MallocChecker – Fix false positive leak for smart pointers in temporary objects (PR #152751)

[Balazs Benics via cfe-commits]

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@@ -1096,6 +1098,47 @@ class StopTrackingCallback final : public SymbolVisitor {
     return true;
   }
 };
+
+/// EscapeTrackedCallback - A SymbolVisitor that marks allocated symbols as
+/// escaped.
+///
+/// This visitor is used to suppress false positive leak reports when smart
+/// pointers are nested in temporary objects passed by value to functions. When
+/// the analyzer can't see the destructor calls for temporary objects, it may
+/// incorrectly report leaks for memory that will be properly freed by the smart
+/// pointer destructors.
+///
+/// The visitor traverses reachable symbols from a given set of memory regions
+/// (typically smart pointer field regions) and marks any allocated symbols as
+/// escaped. Escaped symbols are not reported as leaks by checkDeadSymbols.
+class EscapeTrackedCallback final : public SymbolVisitor {
+  ProgramStateRef State;
+
+  explicit EscapeTrackedCallback(ProgramStateRef S) : State(std::move(S)) {}
+
+public:
+  /// Escape tracked regions reachable from the given roots.
+  static ProgramStateRef
+  EscapeTrackedRegionsReachableFrom(ArrayRef<const MemRegion *> Roots,
+                                    ProgramStateRef State) {
+    EscapeTrackedCallback Visitor(State);
+    for (const MemRegion *R : Roots) {
+      State->scanReachableSymbols(loc::MemRegionVal(R), Visitor);
+    }
+    return Visitor.getState();
+  }
+
+  ProgramStateRef getState() const { return State; }
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steakhal wrote:

I suppose we no longer need this.

https://github.com/llvm/llvm-project/pull/152751