make symbol live only if region is live

Author: balazske

clang/lib/StaticAnalyzer/Core/DynamicExtent.cpp

@@ -131,7 +131,8 @@ ProgramStateRef setDynamicExtent(ProgramStateRef State, const MemRegion *MR,
 void markAllDynamicExtentLive(ProgramStateRef State, SymbolReaper &SymReaper) {
   for (const auto &I : State->get<DynamicExtentMap>())
     if (SymbolRef Sym = I.second.getAsSymbol())
-      SymReaper.markLive(Sym);
+      if (SymReaper.isLiveRegion(I.first))
+        SymReaper.markLive(Sym);
 }
 
 } // namespace ento

clang/lib/StaticAnalyzer/Core/ExprEngine.cpp

@@ -1064,8 +1064,6 @@ void ExprEngine::removeDead(ExplodedNode *Pred, ExplodedNodeSet &Out,
       SymReaper.markLive(MR);
   }
 
-  markAllDynamicExtentLive(CleanedState, SymReaper);
-
   getCheckerManager().runCheckersForLiveSymbols(CleanedState, SymReaper);
 
   // Create a state in which dead bindings are removed from the environment
@@ -1081,6 +1079,11 @@ void ExprEngine::removeDead(ExplodedNode *Pred, ExplodedNodeSet &Out,
   getCheckerManager().runCheckersForDeadSymbols(CheckedSet, Pred, SymReaper,
                                                 DiagnosticStmt, *this, K);
 
+  // Extend lifetime of symbols used for dynamic extent while the parent region
+  // is live. In this way size information about memory allocations is not lost
+  // if the region remains live.
+  markAllDynamicExtentLive(CleanedState, SymReaper);
+
   // For each node in CheckedSet, generate CleanedNodes that have the
   // environment, the store, and the constraints cleaned up but have the
   // user-supplied states as the predecessors.