Add reference chain cycle detection.

diff --git a/libdw/c++/dwarf_output b/libdw/c++/dwarf_output
index 7b948310122d4d342e1f3ca8b5e950697c9e57d5..d2cc7f6d0c09f6e43e3f24ad2e9184d8c91df685 100644 (file)
--- a/libdw/c++/dwarf_output
+++ b/libdw/c++/dwarf_output
@@ -1382,7 +1382,7 @@ namespace elfutils
       typedef typename final_children_getter::
       template copy<debug_info_entry::children_type> get_final_children;
 
-      inline size_t get_reference_hash () const
+      inline size_t get_reference_hash (std::vector<const entry *> &stack) const
       {
        assert (_m_info != NULL);
 
@@ -1401,7 +1401,7 @@ namespace elfutils
            const entry *ref
              = dynamic_cast<const entry *> (it->second._m_value);
            if (ref != NULL)
-             attr_rhashes ^= ref->get_reference_hash ();
+             attr_rhashes ^= ref->get_reference_hash (stack);
           }
        subr::hash_combine (rhash, attr_rhashes);
 
@@ -1720,7 +1720,9 @@ namespace elfutils
         already.  At this point all entries are still pending.  */
       inline void setup_reference_hash () const
       {
-       _m_pending->_m_info->_m_reference_hash = get_reference_hash ();
+       std::vector<const entry *> stack;
+       _m_pending->_m_info->_m_reference_hash = get_reference_hash (stack);
+       assert (stack.empty ());
 
         for (typename std::vector<entry *>::const_iterator it
                = _m_pending->_m_children.begin ();
@@ -1729,11 +1731,30 @@ namespace elfutils
          (*it)->setup_reference_hash ();
       }
 
-      inline size_t get_reference_hash () const
+      inline size_t get_reference_hash (std::vector<const entry *> &stack) const
       {
-       // XXX Need some recursion detection to assert we aren't
-       // running in circles. Probably just pass in stack of entries.
-       return _m_pending->get_reference_hash ();
+       if (std::find (stack.begin (), stack.end (), this) != stack.end ())
+         {
+           std::cout << "Reference chain cycle detected\n"
+                     << "offset=[0x" << std::hex << _m_offset << std::dec
+                     << "] already on the reference chain stack\n";
+           typename std::vector<const entry *>::iterator it;
+           for (it = stack.begin ();
+                it != stack.end ();
+                it++)
+             {
+               std::cout << "offset=[0x" << std::hex << (*it)->_m_offset
+                         << std::dec << "] "
+                         << dwarf::tags::name ((*it)->_m_pending->_m_tag)
+                         << "\n";
+             }
+           abort ();
+         }
+
+       stack.push_back (this);
+       size_t res = _m_pending->get_reference_hash (stack);
+       stack.pop_back ();
+       return res;
       }
 
       // Attempt to turn the pending entry into a final entry.