src/st-heap-object.h

   1 /*
   2  * st-heap-object.c
   3  *
   4  * Copyright (C) 2008 Vincent Geddes
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23 */
  24
  25 #ifndef __ST_HEAP_OBJECT_H__
  26 #define __ST_HEAP_OBJECT_H__
  27
  28 #include <st-types.h>
  29 #include <st-utils.h>
  30 #include <st-descriptor.h>
  31 #include <st-small-integer.h>
  32
  33 /* Every heap-allocated object starts with this layout */
  34 /* format of mark oop
  35  * [ unused: 9 | mark: 1 | format: 6 | tag: 2 ]
  36  *
  37  * format:      object format
  38  * mark:        object contains a forwarding pointer
  39  * unused:      not used yet (haven't implemented GC)
  40  *
  41  */
  42
  43 struct st_header
  44 {
  45     st_oop header;
  46     st_smi hash;
  47     st_oop class;
  48
  49     st_oop fields[];
  50 };
  51
  52 struct st_arrayed_object
  53 {
  54     struct st_header header;
  55     st_oop   size;
  56 };
  57
  58 extern int st_current_hash;
  59
  60 enum
  61 {
  62     st_unused_bits     = 25,
  63     st_mark_bits       = 1,
  64     st_format_bits     = 6,
  65     st_tag_bits        = 2,
  66
  67     st_tag_shift       = 0,
  68     st_format_shift    = st_tag_bits + st_tag_shift,
  69     st_mark_shift      = st_format_bits + st_format_shift,
  70     st_unused_shift    = st_mark_bits + st_mark_shift,
  71
  72     st_format_mask              = ST_NTH_MASK (st_format_bits),
  73     st_format_mask_in_place     = st_format_mask << st_format_shift,
  74     st_mark_mask                = ST_NTH_MASK (st_mark_bits),
  75     st_mark_mask_in_place       = st_mark_mask << st_mark_shift,
  76     st_unused_mask              = ST_NTH_MASK (st_unused_bits),
  77     st_unused_mask_in_place     = st_unused_mask << st_unused_shift,
  78 };
  79
  80 #define  st_heap_object_class(oop)  (ST_POINTER (oop)->class)
  81 #define  st_heap_object_body(oop)   (ST_POINTER (oop)->fields)
  82
  83 #define  ST_ARRAYED_OBJECT(oop)           ((struct st_arrayed_object *) ST_POINTER (oop))
  84
  85 void     st_heap_object_initialize_header (st_oop object, st_oop class);
  86 void     st_heap_object_initialize_body   (st_oop object, st_smi instance_size);
  87 st_uint  st_heap_object_hash              (st_oop object);
  88 void     st_heap_object_set_hash          (st_oop object, int hash);
  89 void       st_heap_object_set_format        (st_oop object, st_uint format);
  90 st_uint  st_heap_object_format           (st_oop object);
  91 bool     st_heap_object_marked          (st_oop object);
  92 void     st_heap_object_set_marked      (st_oop object, bool mark);
  93
  94
  95 void st_object_verify (st_oop object);
  96
  97 void     st_heap_object_install_forwarding_pointer (st_oop object, st_oop pointer);
  98 st_oop   st_heap_object_forwarding_pointer         (st_oop object);
  99
 100 st_descriptor *st_heap_object_descriptor (void);
 101
 102
 103 static inline st_oop
 104 st_arrayed_object_size (st_oop object)
 105 {
 106     return ST_ARRAYED_OBJECT (object)->size;
 107 }
 108
 109 static inline st_descriptor *
 110 st_heap_object_descriptor_for_object (st_oop object)
 111 {
 112     return st_descriptors[st_heap_object_format (object)];
 113 }
 114
 115 #endif /* __ST_HEAP_OBJECT_H__ */