src/share/vm/opto/parse1.cpp

rev 7602 : 8055530: assert(_exits.control()->is_top() || !_gvn.type(ret_phi)->empty()) failed: return value must be well defined
Summary: concurrent class loading causes return phi to become top
Reviewed-by:

*** 984,994 ****
    }
  
    if (tf()->range()->cnt() > TypeFunc::Parms) {
      const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
      Node*       ret_phi  = _gvn.transform( _exits.argument(0) );
!     assert(_exits.control()->is_top() || !_gvn.type(ret_phi)->empty(), "return value must be well defined");
      _exits.push_node(ret_type->basic_type(), ret_phi);
    }
  
    // Note:  Logic for creating and optimizing the ReturnNode is in Compile.
  
--- 984,1003 ----
    }
  
    if (tf()->range()->cnt() > TypeFunc::Parms) {
      const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
      Node*       ret_phi  = _gvn.transform( _exits.argument(0) );
! #ifdef ASSERT 
!     {
!       // In case of concurrent class loading, the type we set for the
!       // ret_phi in build_exits() may have been too optimistic and the
!       // ret_phi may be top now.
!       MutexLockerEx ml(Compile_lock, Mutex::_no_safepoint_check_flag);
!       assert(_exits.control()->is_top() || !_gvn.type(ret_phi)->empty() ||
!              (ret_type->isa_ptr() && C->env()->system_dictionary_modification_counter_changed()), "return value must be well defined");
!     }
! #endif
      _exits.push_node(ret_type->basic_type(), ret_phi);
    }
  
    // Note:  Logic for creating and optimizing the ReturnNode is in Compile.