private_typeinfo: propagate static flags in vmi search_above_dst method

[rprichard]

Summary

Propagate the found_our_static_ptr and found_any_static_type flags from __vmi_class_type_info::search_above_dst to its caller.

Fixes PR33425 and PR33487

[rprichard]

See https://reviews.llvm.org/D36449 for a set of regression tests.

[EricWF]

Could you please include the tests for this change in this review?

[rprichard]

Consolidate the regression test with the bugfix.

[rprichard]

Use arcanist and see if context shows properly on Phabricator.

[EricWF]

Sorry for the delay. This LGTM.

[EricWF]

Committed in r332763.

libcxxabi/trunk/src/private_typeinfo.cpp

else
         //    3.  We can prove that there is no public path to (static_ptr, static_type)
         //        above here.
         const Iter e = __base_info + __base_count;
         Iter p = __base_info;
         // Zero out found flags
         info->found_our_static_ptr = false;
         info->found_any_static_type = false;
         p->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
+        found_our_static_ptr |= info->found_our_static_ptr;
+        found_any_static_type |= info->found_any_static_type;
         if (++p < e)
         {
             do
             {
                 if (info->search_done)
                     break;
                 if (info->found_our_static_ptr)
                 {
else
                     //    then stop looking.
                     if (!(__flags & __non_diamond_repeat_mask))
                         break;
                 }
                 // Zero out found flags
                 info->found_our_static_ptr = false;
                 info->found_any_static_type = false;
                 p->search_above_dst(info, dst_ptr, current_ptr, path_below, use_strcmp);
+                found_our_static_ptr |= info->found_our_static_ptr;
+                found_any_static_type |= info->found_any_static_type;
             } while (++p < e);
         }
         // Restore flags
         info->found_our_static_ptr = found_our_static_ptr;
         info->found_any_static_type = found_any_static_type;
     }
 }
 

test/dynamic_cast.pass.cpp

+//===------------------------- dynamic_cast.pass.cpp ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include <cassert>
+
+// This test explicitly tests dynamic cast with types that have inaccessible
+// bases.
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Winaccessible-base"
+#endif
+
+typedef char Pad1[43981];
+typedef char Pad2[34981];
+typedef char Pad3[93481];
+typedef char Pad4[13489];
+typedef char Pad5[81349];
+typedef char Pad6[34819];
+typedef char Pad7[3489];
+
+namespace t1
+{
+
+// PR33425
+struct C3 { virtual ~C3() {} Pad1 _; };
+struct C5 : protected virtual C3 { Pad2 _; };
+struct C6 : virtual C5 { Pad3 _; };
+struct C7 : virtual C3 { Pad4 _; };
+struct C9 : C6, C7 { Pad5 _; };
+
+C9 c9;
+C3 *c3 = &c9;
+
+void test()
+{
+    assert(dynamic_cast<C3*>(c3) == static_cast<C3*>(&c9));
+    assert(dynamic_cast<C5*>(c3) == static_cast<C5*>(&c9));
+    assert(dynamic_cast<C6*>(c3) == static_cast<C6*>(&c9));
+    assert(dynamic_cast<C7*>(c3) == static_cast<C7*>(&c9));
+    assert(dynamic_cast<C9*>(c3) == static_cast<C9*>(&c9));
+}
+
+}  // t1
+
+namespace t2
+{
+
+// PR33425
+struct Src { virtual ~Src() {} Pad1 _; };
+struct Mask : protected virtual Src { Pad2 _; };
+struct Dest : Mask { Pad3 _; };
+struct Root : Dest, virtual Src { Pad4 _; };
+
+Root root;
+Src *src = &root;
+
+void test()
+{
+    assert(dynamic_cast<Src*>(src) == static_cast<Src*>(&root));
+    assert(dynamic_cast<Mask*>(src) == static_cast<Mask*>(&root));
+    assert(dynamic_cast<Dest*>(src) == static_cast<Dest*>(&root));
+    assert(dynamic_cast<Root*>(src) == static_cast<Root*>(&root));
+}
+
+}  // t2
+
+namespace t3
+{
+
+// PR33487
+struct Class1 { virtual ~Class1() {} Pad1 _; };
+struct Shared : virtual Class1 { Pad2 _; };
+struct Class6 : virtual Shared { Pad3 _; };
+struct Left : Class6 { Pad4 _; };
+struct Right : Class6 { Pad5 _; };
+struct Main : Left, Right { Pad6 _; };
+
+Main m;
+Class1 *c1 = &m;
+
+void test()
+{
+    assert(dynamic_cast<Class1*>(c1) == static_cast<Class1*>(&m));
+    assert(dynamic_cast<Shared*>(c1) == static_cast<Shared*>(&m));
+    assert(dynamic_cast<Class6*>(c1) == 0);
+    assert(dynamic_cast<Left*>(c1) == static_cast<Left*>(&m));
+    assert(dynamic_cast<Right*>(c1) == static_cast<Right*>(&m));
+    assert(dynamic_cast<Main*>(c1) == static_cast<Main*>(&m));
+}
+
+}  // t3
+
+int main()
+{
+    t1::test();
+    t2::test();
+    t3::test();
+}