vm/data_heap_checker.cpp

   1 #include "master.hpp"
   2
   3 /* A tool to debug write barriers. Call check_data_heap() to ensure that all
   4 cards that should be marked are actually marked. */
   5
   6 namespace factor
   7 {
   8
   9 enum generation {
  10         nursery_generation,
  11         aging_generation,
  12         tenured_generation
  13 };
  14
  15 inline generation generation_of(factor_vm *parent, object *obj)
  16 {
  17         if(parent->data->nursery->contains_p(obj))
  18                 return nursery_generation;
  19         else if(parent->data->aging->contains_p(obj))
  20                 return aging_generation;
  21         else if(parent->data->tenured->contains_p(obj))
  22                 return tenured_generation;
  23         else
  24         {
  25                 critical_error("Bad object",(cell)obj);
  26                 return (generation)-1;
  27         }
  28 }
  29
  30 struct slot_checker {
  31         factor_vm *parent;
  32         object *obj;
  33         generation gen;
  34
  35         explicit slot_checker(factor_vm *parent_, object *obj_, generation gen_) :
  36                 parent(parent_), obj(obj_), gen(gen_) {}
  37
  38         void check_write_barrier(cell *slot_ptr, generation target, char mask)
  39         {
  40                 cell object_card_pointer = parent->cards_offset + ((cell)obj >> card_bits);
  41                 cell slot_card_pointer = parent->cards_offset + ((cell)slot_ptr >> card_bits);
  42                 char slot_card_value = *(char *)slot_card_pointer;
  43                 if((slot_card_value & mask) != mask)
  44                 {
  45                         printf("card not marked\n");
  46                         printf("source generation: %d\n",gen);
  47                         printf("target generation: %d\n",target);
  48                         printf("object: 0x%lx\n",(cell)obj);
  49                         printf("object type: %ld\n",obj->type());
  50                         printf("slot pointer: 0x%lx\n",(cell)slot_ptr);
  51                         printf("slot value: 0x%lx\n",*slot_ptr);
  52                         printf("card of object: 0x%lx\n",object_card_pointer);
  53                         printf("card of slot: 0x%lx\n",slot_card_pointer);
  54                         printf("\n");
  55                         parent->factorbug();
  56                 }
  57         }
  58
  59         void operator()(cell *slot_ptr)
  60         {
  61                 if(!immediate_p(*slot_ptr))
  62                 {
  63                         generation target = generation_of(parent,untag<object>(*slot_ptr));
  64                         switch(gen)
  65                         {
  66                         case nursery_generation:
  67                                 break;
  68                         case aging_generation:
  69                                 if(target == nursery_generation)
  70                                         check_write_barrier(slot_ptr,target,card_points_to_nursery);
  71                                 break;
  72                         case tenured_generation:
  73                                 if(target == nursery_generation)
  74                                         check_write_barrier(slot_ptr,target,card_points_to_nursery);
  75                                 else if(target == aging_generation)
  76                                         check_write_barrier(slot_ptr,target,card_points_to_aging);
  77                                 break;
  78                         }
  79                 }
  80         }
  81 };
  82
  83 struct object_checker {
  84         factor_vm *parent;
  85
  86         explicit object_checker(factor_vm *parent_) : parent(parent_) {}
  87
  88         void operator()(object *obj)
  89         {
  90                 slot_checker checker(parent,obj,generation_of(parent,obj));
  91                 obj->each_slot(checker);
  92         }
  93 };
  94
  95 void factor_vm::check_data_heap()
  96 {
  97         object_checker checker(this);
  98         each_object(checker);
  99 }
 100
 101 }