3 files changed, 25 insertions, 4 deletions
diff --git a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
index 52613186677..bd47e897c34 100644
--- a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -552,7 +552,7 @@ void CXXInstanceCall::getInitialStackFrameContents(
 
       // FIXME: CallEvent maybe shouldn't be directly accessing StoreManager.
       bool Failed;
-      ThisVal = StateMgr.getStoreManager().evalDynamicCast(ThisVal, Ty, Failed);
+      ThisVal = StateMgr.getStoreManager().attemptDownCast(ThisVal, Ty, Failed);
       assert(!Failed && "Calling an incorrectly devirtualized method");
     }
 
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index 542399d4bcb..0f40739e1fc 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -386,7 +386,7 @@ void ExprEngine::VisitCast(const CastExpr *CastE, const Expr *Ex,
           Failed = true;
         // Else, evaluate the cast.
         else
-          val = getStoreManager().evalDynamicCast(val, T, Failed);
+          val = getStoreManager().attemptDownCast(val, T, Failed);
 
         if (Failed) {
           if (T->isReferenceType()) {
@@ -412,6 +412,28 @@ void ExprEngine::VisitCast(const CastExpr *CastE, const Expr *Ex,
         Bldr.generateNode(CastE, Pred, state);
         continue;
       }
+      case CK_BaseToDerived: {
+        SVal val = state->getSVal(Ex, LCtx);
+        QualType resultType = CastE->getType();
+        if (CastE->isGLValue())
+          resultType = getContext().getPointerType(resultType);
+
+        bool Failed = false;
+
+        if (!val.isConstant()) {
+          val = getStoreManager().attemptDownCast(val, T, Failed);
+        }
+
+        // Failed to cast or the result is unknown, fall back to conservative.
+        if (Failed || val.isUnknown()) {
+          val =
+            svalBuilder.conjureSymbolVal(nullptr, CastE, LCtx, resultType,
+                                         currBldrCtx->blockCount());
+        }
+        state = state->BindExpr(CastE, LCtx, val);
+        Bldr.generateNode(CastE, Pred, state);
+        continue;
+      }
       case CK_NullToMemberPointer: {
         // FIXME: For now, member pointers are represented by void *.
         SVal V = svalBuilder.makeNull();
@@ -421,7 +443,6 @@ void ExprEngine::VisitCast(const CastExpr *CastE, const Expr *Ex,
       }
       // Various C++ casts that are not handled yet.
       case CK_ToUnion:
-      case CK_BaseToDerived:
       case CK_BaseToDerivedMemberPointer:
       case CK_DerivedToBaseMemberPointer:
       case CK_ReinterpretMemberPointer:
diff --git a/clang/lib/StaticAnalyzer/Core/Store.cpp b/clang/lib/StaticAnalyzer/Core/Store.cpp
index de29f0eedd1..aca6e3b6255 100644
--- a/clang/lib/StaticAnalyzer/Core/Store.cpp
+++ b/clang/lib/StaticAnalyzer/Core/Store.cpp
@@ -292,7 +292,7 @@ static const CXXRecordDecl *getCXXRecordType(const MemRegion *MR) {
   return nullptr;
 }
 
-SVal StoreManager::evalDynamicCast(SVal Base, QualType TargetType,
+SVal StoreManager::attemptDownCast(SVal Base, QualType TargetType,
                                    bool &Failed) {
   Failed = false;