1 files changed, 464 insertions, 50 deletions

diff --git a/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp b/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
index bcc7d4103c1c..6ee7bd9252b3 100644
--- a/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
+++ b/contrib/llvm-project/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
@@ -15,24 +15,31 @@
 #include "SmartPtr.h"
 
 #include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclarationName.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/Type.h"
+#include "clang/Basic/LLVM.h"
 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
 #include "clang/StaticAnalyzer/Core/Checker.h"
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
+#include <string>
 
 using namespace clang;
 using namespace ento;
 
 namespace {
-class SmartPtrModeling : public Checker<eval::Call, check::DeadSymbols> {
+class SmartPtrModeling
+    : public Checker<eval::Call, check::DeadSymbols, check::RegionChanges,
+                     check::LiveSymbols> {
 
-  bool isNullAfterMoveMethod(const CallEvent &Call) const;
+  bool isBoolConversionMethod(const CallEvent &Call) const;
 
 public:
   // Whether the checker should model for null dereferences of smart pointers.
@@ -40,20 +47,35 @@ public:
   bool evalCall(const CallEvent &Call, CheckerContext &C) const;
   void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
   void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
+  ProgramStateRef
+  checkRegionChanges(ProgramStateRef State,
+                     const InvalidatedSymbols *Invalidated,
+                     ArrayRef<const MemRegion *> ExplicitRegions,
+                     ArrayRef<const MemRegion *> Regions,
+                     const LocationContext *LCtx, const CallEvent *Call) const;
+  void printState(raw_ostream &Out, ProgramStateRef State, const char *NL,
+                  const char *Sep) const override;
+  void checkLiveSymbols(ProgramStateRef State, SymbolReaper &SR) const;
 
 private:
-  ProgramStateRef updateTrackedRegion(const CallEvent &Call, CheckerContext &C,
-                                      const MemRegion *ThisValRegion) const;
   void handleReset(const CallEvent &Call, CheckerContext &C) const;
   void handleRelease(const CallEvent &Call, CheckerContext &C) const;
   void handleSwap(const CallEvent &Call, CheckerContext &C) const;
+  void handleGet(const CallEvent &Call, CheckerContext &C) const;
+  bool handleAssignOp(const CallEvent &Call, CheckerContext &C) const;
+  bool handleMoveCtr(const CallEvent &Call, CheckerContext &C,
+                     const MemRegion *ThisRegion) const;
+  bool updateMovedSmartPointers(CheckerContext &C, const MemRegion *ThisRegion,
+                                const MemRegion *OtherSmartPtrRegion) const;
+  void handleBoolConversion(const CallEvent &Call, CheckerContext &C) const;
 
   using SmartPtrMethodHandlerFn =
       void (SmartPtrModeling::*)(const CallEvent &Call, CheckerContext &) const;
   CallDescriptionMap<SmartPtrMethodHandlerFn> SmartPtrMethodHandlers{
       {{"reset"}, &SmartPtrModeling::handleReset},
       {{"release"}, &SmartPtrModeling::handleRelease},
-      {{"swap", 1}, &SmartPtrModeling::handleSwap}};
+      {{"swap", 1}, &SmartPtrModeling::handleSwap},
+      {{"get"}, &SmartPtrModeling::handleGet}};
 };
 } // end of anonymous namespace
 
@@ -81,13 +103,70 @@ bool isStdSmartPtrCall(const CallEvent &Call) {
 
 bool isNullSmartPtr(const ProgramStateRef State, const MemRegion *ThisRegion) {
   const auto *InnerPointVal = State->get<TrackedRegionMap>(ThisRegion);
-  return InnerPointVal && InnerPointVal->isZeroConstant();
+  return InnerPointVal &&
+         !State->assume(InnerPointVal->castAs<DefinedOrUnknownSVal>(), true);
 }
 } // namespace smartptr
 } // namespace ento
 } // namespace clang
 
-bool SmartPtrModeling::isNullAfterMoveMethod(const CallEvent &Call) const {
+// If a region is removed all of the subregions need to be removed too.
+static TrackedRegionMapTy
+removeTrackedSubregions(TrackedRegionMapTy RegionMap,
+                        TrackedRegionMapTy::Factory &RegionMapFactory,
+                        const MemRegion *Region) {
+  if (!Region)
+    return RegionMap;
+  for (const auto &E : RegionMap) {
+    if (E.first->isSubRegionOf(Region))
+      RegionMap = RegionMapFactory.remove(RegionMap, E.first);
+  }
+  return RegionMap;
+}
+
+static ProgramStateRef updateSwappedRegion(ProgramStateRef State,
+                                           const MemRegion *Region,
+                                           const SVal *RegionInnerPointerVal) {
+  if (RegionInnerPointerVal) {
+    State = State->set<TrackedRegionMap>(Region, *RegionInnerPointerVal);
+  } else {
+    State = State->remove<TrackedRegionMap>(Region);
+  }
+  return State;
+}
+
+// Helper method to get the inner pointer type of specialized smart pointer
+// Returns empty type if not found valid inner pointer type.
+static QualType getInnerPointerType(const CallEvent &Call, CheckerContext &C) {
+  const auto *MethodDecl = dyn_cast_or_null<CXXMethodDecl>(Call.getDecl());
+  if (!MethodDecl || !MethodDecl->getParent())
+    return {};
+
+  const auto *RecordDecl = MethodDecl->getParent();
+  if (!RecordDecl || !RecordDecl->isInStdNamespace())
+    return {};
+
+  const auto *TSD = dyn_cast<ClassTemplateSpecializationDecl>(RecordDecl);
+  if (!TSD)
+    return {};
+
+  auto TemplateArgs = TSD->getTemplateArgs().asArray();
+  if (TemplateArgs.size() == 0)
+    return {};
+  auto InnerValueType = TemplateArgs[0].getAsType();
+  return C.getASTContext().getPointerType(InnerValueType.getCanonicalType());
+}
+
+// Helper method to pretty print region and avoid extra spacing.
+static void checkAndPrettyPrintRegion(llvm::raw_ostream &OS,
+                                      const MemRegion *Region) {
+  if (Region->canPrintPretty()) {
+    OS << " ";
+    Region->printPretty(OS);
+  }
+}
+
+bool SmartPtrModeling::isBoolConversionMethod(const CallEvent &Call) const {
   // TODO: Update CallDescription to support anonymous calls?
   // TODO: Handle other methods, such as .get() or .release().
   // But once we do, we'd need a visitor to explain null dereferences
@@ -98,43 +177,93 @@ bool SmartPtrModeling::isNullAfterMoveMethod(const CallEvent &Call) const {
 
 bool SmartPtrModeling::evalCall(const CallEvent &Call,
                                 CheckerContext &C) const {
-
+  ProgramStateRef State = C.getState();
   if (!smartptr::isStdSmartPtrCall(Call))
     return false;
 
-  if (isNullAfterMoveMethod(Call)) {
-    ProgramStateRef State = C.getState();
+  if (isBoolConversionMethod(Call)) {
     const MemRegion *ThisR =
         cast<CXXInstanceCall>(&Call)->getCXXThisVal().getAsRegion();
 
-    if (!move::isMovedFrom(State, ThisR)) {
-      // TODO: Model this case as well. At least, avoid invalidation of globals.
-      return false;
+    if (ModelSmartPtrDereference) {
+      // The check for the region is moved is duplicated in handleBoolOperation
+      // method.
+      // FIXME: Once we model std::move for smart pointers clean up this and use
+      // that modeling.
+      handleBoolConversion(Call, C);
+      return true;
+    } else {
+      if (!move::isMovedFrom(State, ThisR)) {
+        // TODO: Model this case as well. At least, avoid invalidation of
+        // globals.
+        return false;
+      }
+
+      // TODO: Add a note to bug reports describing this decision.
+      C.addTransition(State->BindExpr(
+          Call.getOriginExpr(), C.getLocationContext(),
+          C.getSValBuilder().makeZeroVal(Call.getResultType())));
+
+      return true;
     }
-
-    // TODO: Add a note to bug reports describing this decision.
-    C.addTransition(
-        State->BindExpr(Call.getOriginExpr(), C.getLocationContext(),
-                        C.getSValBuilder().makeZeroVal(Call.getResultType())));
-    return true;
   }
 
   if (!ModelSmartPtrDereference)
     return false;
 
   if (const auto *CC = dyn_cast<CXXConstructorCall>(&Call)) {
-    if (CC->getDecl()->isCopyOrMoveConstructor())
+    if (CC->getDecl()->isCopyConstructor())
       return false;
 
-    const MemRegion *ThisValRegion = CC->getCXXThisVal().getAsRegion();
-    if (!ThisValRegion)
+    const MemRegion *ThisRegion = CC->getCXXThisVal().getAsRegion();
+    if (!ThisRegion)
       return false;
 
-    auto State = updateTrackedRegion(Call, C, ThisValRegion);
-    C.addTransition(State);
+    if (CC->getDecl()->isMoveConstructor())
+      return handleMoveCtr(Call, C, ThisRegion);
+
+    if (Call.getNumArgs() == 0) {
+      auto NullVal = C.getSValBuilder().makeNull();
+      State = State->set<TrackedRegionMap>(ThisRegion, NullVal);
+
+      C.addTransition(
+          State, C.getNoteTag([ThisRegion](PathSensitiveBugReport &BR,
+                                           llvm::raw_ostream &OS) {
+            if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+                !BR.isInteresting(ThisRegion))
+              return;
+            OS << "Default constructed smart pointer";
+            checkAndPrettyPrintRegion(OS, ThisRegion);
+            OS << " is null";
+          }));
+    } else {
+      const auto *TrackingExpr = Call.getArgExpr(0);
+      assert(TrackingExpr->getType()->isPointerType() &&
+             "Adding a non pointer value to TrackedRegionMap");
+      auto ArgVal = Call.getArgSVal(0);
+      State = State->set<TrackedRegionMap>(ThisRegion, ArgVal);
+
+      C.addTransition(State, C.getNoteTag([ThisRegion, TrackingExpr,
+                                           ArgVal](PathSensitiveBugReport &BR,
+                                                   llvm::raw_ostream &OS) {
+        if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+            !BR.isInteresting(ThisRegion))
+          return;
+        bugreporter::trackExpressionValue(BR.getErrorNode(), TrackingExpr, BR);
+        OS << "Smart pointer";
+        checkAndPrettyPrintRegion(OS, ThisRegion);
+        if (ArgVal.isZeroConstant())
+          OS << " is constructed using a null value";
+        else
+          OS << " is constructed";
+      }));
+    }
     return true;
   }
 
+  if (handleAssignOp(Call, C))
+    return true;
+
   const SmartPtrMethodHandlerFn *Handler = SmartPtrMethodHandlers.lookup(Call);
   if (!Handler)
     return false;
@@ -158,66 +287,351 @@ void SmartPtrModeling::checkDeadSymbols(SymbolReaper &SymReaper,
   C.addTransition(State);
 }
 
+void SmartPtrModeling::printState(raw_ostream &Out, ProgramStateRef State,
+                                  const char *NL, const char *Sep) const {
+  TrackedRegionMapTy RS = State->get<TrackedRegionMap>();
+
+  if (!RS.isEmpty()) {
+    Out << Sep << "Smart ptr regions :" << NL;
+    for (auto I : RS) {
+      I.first->dumpToStream(Out);
+      if (smartptr::isNullSmartPtr(State, I.first))
+        Out << ": Null";
+      else
+        Out << ": Non Null";
+      Out << NL;
+    }
+  }
+}
+
+ProgramStateRef SmartPtrModeling::checkRegionChanges(
+    ProgramStateRef State, const InvalidatedSymbols *Invalidated,
+    ArrayRef<const MemRegion *> ExplicitRegions,
+    ArrayRef<const MemRegion *> Regions, const LocationContext *LCtx,
+    const CallEvent *Call) const {
+  TrackedRegionMapTy RegionMap = State->get<TrackedRegionMap>();
+  TrackedRegionMapTy::Factory &RegionMapFactory =
+      State->get_context<TrackedRegionMap>();
+  for (const auto *Region : Regions)
+    RegionMap = removeTrackedSubregions(RegionMap, RegionMapFactory,
+                                        Region->getBaseRegion());
+  return State->set<TrackedRegionMap>(RegionMap);
+}
+
+void SmartPtrModeling::checkLiveSymbols(ProgramStateRef State,
+                                        SymbolReaper &SR) const {
+  // Marking tracked symbols alive
+  TrackedRegionMapTy TrackedRegions = State->get<TrackedRegionMap>();
+  for (auto I = TrackedRegions.begin(), E = TrackedRegions.end(); I != E; ++I) {
+    SVal Val = I->second;
+    for (auto si = Val.symbol_begin(), se = Val.symbol_end(); si != se; ++si) {
+      SR.markLive(*si);
+    }
+  }
+}
+
 void SmartPtrModeling::handleReset(const CallEvent &Call,
                                    CheckerContext &C) const {
+  ProgramStateRef State = C.getState();
   const auto *IC = dyn_cast<CXXInstanceCall>(&Call);
   if (!IC)
     return;
 
-  const MemRegion *ThisValRegion = IC->getCXXThisVal().getAsRegion();
-  if (!ThisValRegion)
+  const MemRegion *ThisRegion = IC->getCXXThisVal().getAsRegion();
+  if (!ThisRegion)
     return;
-  auto State = updateTrackedRegion(Call, C, ThisValRegion);
-  C.addTransition(State);
-  // TODO: Make sure to ivalidate the the region in the Store if we don't have
+
+  assert(Call.getArgExpr(0)->getType()->isPointerType() &&
+         "Adding a non pointer value to TrackedRegionMap");
+  State = State->set<TrackedRegionMap>(ThisRegion, Call.getArgSVal(0));
+  const auto *TrackingExpr = Call.getArgExpr(0);
+  C.addTransition(
+      State, C.getNoteTag([ThisRegion, TrackingExpr](PathSensitiveBugReport &BR,
+                                                     llvm::raw_ostream &OS) {
+        if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+            !BR.isInteresting(ThisRegion))
+          return;
+        bugreporter::trackExpressionValue(BR.getErrorNode(), TrackingExpr, BR);
+        OS << "Smart pointer";
+        checkAndPrettyPrintRegion(OS, ThisRegion);
+        OS << " reset using a null value";
+      }));
+  // TODO: Make sure to ivalidate the region in the Store if we don't have
   // time to model all methods.
 }
 
 void SmartPtrModeling::handleRelease(const CallEvent &Call,
                                      CheckerContext &C) const {
+  ProgramStateRef State = C.getState();
   const auto *IC = dyn_cast<CXXInstanceCall>(&Call);
   if (!IC)
     return;
 
-  const MemRegion *ThisValRegion = IC->getCXXThisVal().getAsRegion();
-  if (!ThisValRegion)
+  const MemRegion *ThisRegion = IC->getCXXThisVal().getAsRegion();
+  if (!ThisRegion)
     return;
 
-  auto State = updateTrackedRegion(Call, C, ThisValRegion);
+  const auto *InnerPointVal = State->get<TrackedRegionMap>(ThisRegion);
 
-  const auto *InnerPointVal = State->get<TrackedRegionMap>(ThisValRegion);
   if (InnerPointVal) {
     State = State->BindExpr(Call.getOriginExpr(), C.getLocationContext(),
                             *InnerPointVal);
   }
-  C.addTransition(State);
+
+  auto ValueToUpdate = C.getSValBuilder().makeNull();
+  State = State->set<TrackedRegionMap>(ThisRegion, ValueToUpdate);
+
+  C.addTransition(State, C.getNoteTag([ThisRegion](PathSensitiveBugReport &BR,
+                                                   llvm::raw_ostream &OS) {
+    if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+        !BR.isInteresting(ThisRegion))
+      return;
+
+    OS << "Smart pointer";
+    checkAndPrettyPrintRegion(OS, ThisRegion);
+    OS << " is released and set to null";
+  }));
   // TODO: Add support to enable MallocChecker to start tracking the raw
   // pointer.
 }
 
 void SmartPtrModeling::handleSwap(const CallEvent &Call,
                                   CheckerContext &C) const {
-  // TODO: Add support to handle swap method.
+  // To model unique_ptr::swap() method.
+  const auto *IC = dyn_cast<CXXInstanceCall>(&Call);
+  if (!IC)
+    return;
+
+  const MemRegion *ThisRegion = IC->getCXXThisVal().getAsRegion();
+  if (!ThisRegion)
+    return;
+
+  const auto *ArgRegion = Call.getArgSVal(0).getAsRegion();
+  if (!ArgRegion)
+    return;
+
+  auto State = C.getState();
+  const auto *ThisRegionInnerPointerVal =
+      State->get<TrackedRegionMap>(ThisRegion);
+  const auto *ArgRegionInnerPointerVal =
+      State->get<TrackedRegionMap>(ArgRegion);
+
+  // Swap the tracked region values.
+  State = updateSwappedRegion(State, ThisRegion, ArgRegionInnerPointerVal);
+  State = updateSwappedRegion(State, ArgRegion, ThisRegionInnerPointerVal);
+
+  C.addTransition(
+      State, C.getNoteTag([ThisRegion, ArgRegion](PathSensitiveBugReport &BR,
+                                                  llvm::raw_ostream &OS) {
+        if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+            !BR.isInteresting(ThisRegion))
+          return;
+        BR.markInteresting(ArgRegion);
+        OS << "Swapped null smart pointer";
+        checkAndPrettyPrintRegion(OS, ArgRegion);
+        OS << " with smart pointer";
+        checkAndPrettyPrintRegion(OS, ThisRegion);
+      }));
 }
 
-ProgramStateRef
-SmartPtrModeling::updateTrackedRegion(const CallEvent &Call, CheckerContext &C,
-                                      const MemRegion *ThisValRegion) const {
-  // TODO: Refactor and clean up handling too many things.
+void SmartPtrModeling::handleGet(const CallEvent &Call,
+                                 CheckerContext &C) const {
   ProgramStateRef State = C.getState();
-  auto NumArgs = Call.getNumArgs();
-
-  if (NumArgs == 0) {
-    auto NullSVal = C.getSValBuilder().makeNull();
-    State = State->set<TrackedRegionMap>(ThisValRegion, NullSVal);
-  } else if (NumArgs == 1) {
-    auto ArgVal = Call.getArgSVal(0);
-    assert(Call.getArgExpr(0)->getType()->isPointerType() &&
-           "Adding a non pointer value to TrackedRegionMap");
-    State = State->set<TrackedRegionMap>(ThisValRegion, ArgVal);
+  const auto *IC = dyn_cast<CXXInstanceCall>(&Call);
+  if (!IC)
+    return;
+
+  const MemRegion *ThisRegion = IC->getCXXThisVal().getAsRegion();
+  if (!ThisRegion)
+    return;
+
+  SVal InnerPointerVal;
+  if (const auto *InnerValPtr = State->get<TrackedRegionMap>(ThisRegion)) {
+    InnerPointerVal = *InnerValPtr;
+  } else {
+    const auto *CallExpr = Call.getOriginExpr();
+    InnerPointerVal = C.getSValBuilder().conjureSymbolVal(
+        CallExpr, C.getLocationContext(), Call.getResultType(), C.blockCount());
+    State = State->set<TrackedRegionMap>(ThisRegion, InnerPointerVal);
   }
 
-  return State;
+  State = State->BindExpr(Call.getOriginExpr(), C.getLocationContext(),
+                          InnerPointerVal);
+  // TODO: Add NoteTag, for how the raw pointer got using 'get' method.
+  C.addTransition(State);
+}
+
+bool SmartPtrModeling::handleAssignOp(const CallEvent &Call,
+                                      CheckerContext &C) const {
+  ProgramStateRef State = C.getState();
+  const auto *OC = dyn_cast<CXXMemberOperatorCall>(&Call);
+  if (!OC)
+    return false;
+  OverloadedOperatorKind OOK = OC->getOverloadedOperator();
+  if (OOK != OO_Equal)
+    return false;
+  const MemRegion *ThisRegion = OC->getCXXThisVal().getAsRegion();
+  if (!ThisRegion)
+    return false;
+
+  const MemRegion *OtherSmartPtrRegion = OC->getArgSVal(0).getAsRegion();
+  // In case of 'nullptr' or '0' assigned
+  if (!OtherSmartPtrRegion) {
+    bool AssignedNull = Call.getArgSVal(0).isZeroConstant();
+    if (!AssignedNull)
+      return false;
+    auto NullVal = C.getSValBuilder().makeNull();
+    State = State->set<TrackedRegionMap>(ThisRegion, NullVal);
+    C.addTransition(State, C.getNoteTag([ThisRegion](PathSensitiveBugReport &BR,
+                                                     llvm::raw_ostream &OS) {
+      if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+          !BR.isInteresting(ThisRegion))
+        return;
+      OS << "Smart pointer";
+      checkAndPrettyPrintRegion(OS, ThisRegion);
+      OS << " is assigned to null";
+    }));
+    return true;
+  }
+
+  return updateMovedSmartPointers(C, ThisRegion, OtherSmartPtrRegion);
+}
+
+bool SmartPtrModeling::handleMoveCtr(const CallEvent &Call, CheckerContext &C,
+                                     const MemRegion *ThisRegion) const {
+  const auto *OtherSmartPtrRegion = Call.getArgSVal(0).getAsRegion();
+  if (!OtherSmartPtrRegion)
+    return false;
+
+  return updateMovedSmartPointers(C, ThisRegion, OtherSmartPtrRegion);
+}
+
+bool SmartPtrModeling::updateMovedSmartPointers(
+    CheckerContext &C, const MemRegion *ThisRegion,
+    const MemRegion *OtherSmartPtrRegion) const {
+  ProgramStateRef State = C.getState();
+  const auto *OtherInnerPtr = State->get<TrackedRegionMap>(OtherSmartPtrRegion);
+  if (OtherInnerPtr) {
+    State = State->set<TrackedRegionMap>(ThisRegion, *OtherInnerPtr);
+    auto NullVal = C.getSValBuilder().makeNull();
+    State = State->set<TrackedRegionMap>(OtherSmartPtrRegion, NullVal);
+    bool IsArgValNull = OtherInnerPtr->isZeroConstant();
+
+    C.addTransition(
+        State,
+        C.getNoteTag([ThisRegion, OtherSmartPtrRegion, IsArgValNull](
+                         PathSensitiveBugReport &BR, llvm::raw_ostream &OS) {
+          if (&BR.getBugType() != smartptr::getNullDereferenceBugType())
+            return;
+          if (BR.isInteresting(OtherSmartPtrRegion)) {
+            OS << "Smart pointer";
+            checkAndPrettyPrintRegion(OS, OtherSmartPtrRegion);
+            OS << " is null after being moved to";
+            checkAndPrettyPrintRegion(OS, ThisRegion);
+          }
+          if (BR.isInteresting(ThisRegion) && IsArgValNull) {
+            OS << "A null pointer value is moved to";
+            checkAndPrettyPrintRegion(OS, ThisRegion);
+            BR.markInteresting(OtherSmartPtrRegion);
+          }
+        }));
+    return true;
+  } else {
+    // In case we dont know anything about value we are moving from
+    // remove the entry from map for which smart pointer got moved to.
+    auto NullVal = C.getSValBuilder().makeNull();
+    State = State->remove<TrackedRegionMap>(ThisRegion);
+    State = State->set<TrackedRegionMap>(OtherSmartPtrRegion, NullVal);
+    C.addTransition(State, C.getNoteTag([OtherSmartPtrRegion,
+                                         ThisRegion](PathSensitiveBugReport &BR,
+                                                     llvm::raw_ostream &OS) {
+      if (&BR.getBugType() != smartptr::getNullDereferenceBugType() ||
+          !BR.isInteresting(OtherSmartPtrRegion))
+        return;
+      OS << "Smart pointer";
+      checkAndPrettyPrintRegion(OS, OtherSmartPtrRegion);
+      OS << " is null after; previous value moved to";
+      checkAndPrettyPrintRegion(OS, ThisRegion);
+    }));
+    return true;
+  }
+  return false;
+}
+
+void SmartPtrModeling::handleBoolConversion(const CallEvent &Call,
+                                            CheckerContext &C) const {
+  // To model unique_ptr::operator bool
+  ProgramStateRef State = C.getState();
+  const Expr *CallExpr = Call.getOriginExpr();
+  const MemRegion *ThisRegion =
+      cast<CXXInstanceCall>(&Call)->getCXXThisVal().getAsRegion();
+
+  SVal InnerPointerVal;
+  if (const auto *InnerValPtr = State->get<TrackedRegionMap>(ThisRegion)) {
+    InnerPointerVal = *InnerValPtr;
+  } else {
+    // In case of inner pointer SVal is not available we create
+    // conjureSymbolVal for inner pointer value.
+    auto InnerPointerType = getInnerPointerType(Call, C);
+    if (InnerPointerType.isNull())
+      return;
+
+    const LocationContext *LC = C.getLocationContext();
+    InnerPointerVal = C.getSValBuilder().conjureSymbolVal(
+        CallExpr, LC, InnerPointerType, C.blockCount());
+    State = State->set<TrackedRegionMap>(ThisRegion, InnerPointerVal);
+  }
+
+  if (State->isNull(InnerPointerVal).isConstrainedTrue()) {
+    State = State->BindExpr(CallExpr, C.getLocationContext(),
+                            C.getSValBuilder().makeTruthVal(false));
+
+    C.addTransition(State);
+    return;
+  } else if (State->isNonNull(InnerPointerVal).isConstrainedTrue()) {
+    State = State->BindExpr(CallExpr, C.getLocationContext(),
+                            C.getSValBuilder().makeTruthVal(true));
+
+    C.addTransition(State);
+    return;
+  } else if (move::isMovedFrom(State, ThisRegion)) {
+    C.addTransition(
+        State->BindExpr(CallExpr, C.getLocationContext(),
+                        C.getSValBuilder().makeZeroVal(Call.getResultType())));
+    return;
+  } else {
+    ProgramStateRef NotNullState, NullState;
+    std::tie(NotNullState, NullState) =
+        State->assume(InnerPointerVal.castAs<DefinedOrUnknownSVal>());
+
+    auto NullVal = C.getSValBuilder().makeNull();
+    // Explicitly tracking the region as null.
+    NullState = NullState->set<TrackedRegionMap>(ThisRegion, NullVal);
+
+    NullState = NullState->BindExpr(CallExpr, C.getLocationContext(),
+                                    C.getSValBuilder().makeTruthVal(false));
+    C.addTransition(NullState, C.getNoteTag(
+                                   [ThisRegion](PathSensitiveBugReport &BR,
+                                                llvm::raw_ostream &OS) {
+                                     OS << "Assuming smart pointer";
+                                     checkAndPrettyPrintRegion(OS, ThisRegion);
+                                     OS << " is null";
+                                   },
+                                   /*IsPrunable=*/true));
+    NotNullState =
+        NotNullState->BindExpr(CallExpr, C.getLocationContext(),
+                               C.getSValBuilder().makeTruthVal(true));
+    C.addTransition(
+        NotNullState,
+        C.getNoteTag(
+            [ThisRegion](PathSensitiveBugReport &BR, llvm::raw_ostream &OS) {
+              OS << "Assuming smart pointer";
+              checkAndPrettyPrintRegion(OS, ThisRegion);
+              OS << " is non-null";
+            },
+            /*IsPrunable=*/true));
+    return;
+  }
 }
 
 void ento::registerSmartPtrModeling(CheckerManager &Mgr) {