Offset from vptr to the start of most-derived object can actually
be positive in some virtual base class vtables.
Patch by Stephan Bergmann!
llvm-svn: 244101
struct VtablePrefix {
/// The offset from the vptr to the start of the most-derived object.
- /// This should never be greater than zero, and will usually be exactly
- /// zero.
+ /// This will only be greater than zero in some virtual base class vtables
+ /// used during object con-/destruction, and will usually be exactly zero.
sptr Offset;
/// The type_info object describing the most-derived class type.
std::type_info *TypeInfo;
if (!Vptr)
return 0;
VtablePrefix *Prefix = Vptr - 1;
- if (Prefix->Offset > 0 || !Prefix->TypeInfo)
+ if (!Prefix->TypeInfo)
// This can't possibly be a valid vtable.
return 0;
return Prefix;
--- /dev/null
+// RUN: %clangxx -frtti -fsanitize=vptr -fno-sanitize-recover=vptr %s -o %t
+// RUN: %run %t
+
+// REQUIRES: cxxabi
+
+int volatile n;
+
+struct A { virtual ~A() {} };
+struct B: virtual A {};
+struct C: virtual A { ~C() { n = 0; } };
+struct D: virtual B, virtual C {};
+
+int main() { delete new D; }