static CXXDynamicCastExpr *CreateEmpty(ASTContext &Context,
unsigned pathSize);
+ bool isAlwaysNull() const;
+
static bool classof(const Stmt *T) {
return T->getStmtClass() == CXXDynamicCastExprClass;
}
return new (Buffer) CXXDynamicCastExpr(EmptyShell(), PathSize);
}
+/// isAlwaysNull - Return whether the result of the dynamic_cast is proven
+/// to always be null. For example:
+///
+/// struct A { };
+/// struct B final : A { };
+/// struct C { };
+///
+/// C *f(B* b) { return dynamic_cast<C*>(b); }
+bool CXXDynamicCastExpr::isAlwaysNull() const
+{
+ QualType SrcType = getSubExpr()->getType();
+ QualType DestType = getType();
+
+ if (const PointerType *SrcPTy = SrcType->getAs<PointerType>()) {
+ SrcType = SrcPTy->getPointeeType();
+ DestType = DestType->castAs<PointerType>()->getPointeeType();
+ }
+
+ const CXXRecordDecl *SrcRD =
+ cast<CXXRecordDecl>(SrcType->castAs<RecordType>()->getDecl());
+
+ if (!SrcRD->hasAttr<FinalAttr>())
+ return false;
+
+ const CXXRecordDecl *DestRD =
+ cast<CXXRecordDecl>(DestType->castAs<RecordType>()->getDecl());
+
+ return !DestRD->isDerivedFrom(SrcRD);
+}
+
CXXReinterpretCastExpr *
CXXReinterpretCastExpr::Create(ASTContext &C, QualType T, ExprValueKind VK,
CastKind K, Expr *Op,