[analyzer] Enforce super-region classes for various memory regions.

We now check the type of the super-region pointer for most SubRegion classes
in compile time; some checks are run-time though.

This is an API-breaking change (we now require explicit casts to specific region
sub-classes), but in practice very few checkers are affected.

Differential Revision: https://reviews.llvm.org/D26838

llvm-svn: 300189

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
index ca2e2424b23..03e0095d0e8 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
@@ -512,7 +512,8 @@ void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
   if (CNE->isArray()) {
     // FIXME: allocating an array requires simulating the constructors.
     // For now, just return a symbolicated region.
-    const MemRegion *NewReg = symVal.castAs<loc::MemRegionVal>().getRegion();
+    const SubRegion *NewReg =
+        symVal.castAs<loc::MemRegionVal>().getRegionAs<SubRegion>();
     QualType ObjTy = CNE->getType()->getAs<PointerType>()->getPointeeType();
     const ElementRegion *EleReg =
       getStoreManager().GetElementZeroRegion(NewReg, ObjTy);