external/mit/lua/dist/src/lgc.h

   1 /*      $NetBSD: lgc.h,v 1.1.1.2 2012/03/15 00:08:10 alnsn Exp $        */
   2
   3 /*
   4 ** $Id: lgc.h,v 1.1.1.2 2012/03/15 00:08:10 alnsn Exp $
   5 ** Garbage Collector
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9 #ifndef lgc_h
  10 #define lgc_h
  11
  12
  13 #include "lobject.h"
  14
  15
  16 /*
  17 ** Possible states of the Garbage Collector
  18 */
  19 #define GCSpause        0
  20 #define GCSpropagate    1
  21 #define GCSsweepstring  2
  22 #define GCSsweep        3
  23 #define GCSfinalize     4
  24
  25
  26 /*
  27 ** some userful bit tricks
  28 */
  29 #define resetbits(x,m)  ((x) &= cast(lu_byte, ~(m)))
  30 #define setbits(x,m)    ((x) |= (m))
  31 #define testbits(x,m)   ((x) & (m))
  32 #define bitmask(b)      (1<<(b))
  33 #define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2))
  34 #define l_setbit(x,b)   setbits(x, bitmask(b))
  35 #define resetbit(x,b)   resetbits(x, bitmask(b))
  36 #define testbit(x,b)    testbits(x, bitmask(b))
  37 #define set2bits(x,b1,b2)       setbits(x, (bit2mask(b1, b2)))
  38 #define reset2bits(x,b1,b2)     resetbits(x, (bit2mask(b1, b2)))
  39 #define test2bits(x,b1,b2)      testbits(x, (bit2mask(b1, b2)))
  40
  41
  42
  43 /*
  44 ** Layout for bit use in `marked' field:
  45 ** bit 0 - object is white (type 0)
  46 ** bit 1 - object is white (type 1)
  47 ** bit 2 - object is black
  48 ** bit 3 - for userdata: has been finalized
  49 ** bit 3 - for tables: has weak keys
  50 ** bit 4 - for tables: has weak values
  51 ** bit 5 - object is fixed (should not be collected)
  52 ** bit 6 - object is "super" fixed (only the main thread)
  53 */
  54
  55
  56 #define WHITE0BIT       0
  57 #define WHITE1BIT       1
  58 #define BLACKBIT        2
  59 #define FINALIZEDBIT    3
  60 #define KEYWEAKBIT      3
  61 #define VALUEWEAKBIT    4
  62 #define FIXEDBIT        5
  63 #define SFIXEDBIT       6
  64 #define WHITEBITS       bit2mask(WHITE0BIT, WHITE1BIT)
  65
  66
  67 #define iswhite(x)      test2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
  68 #define isblack(x)      testbit((x)->gch.marked, BLACKBIT)
  69 #define isgray(x)       (!isblack(x) && !iswhite(x))
  70
  71 #define otherwhite(g)   (g->currentwhite ^ WHITEBITS)
  72 #define isdead(g,v)     ((v)->gch.marked & otherwhite(g) & WHITEBITS)
  73
  74 #define changewhite(x)  ((x)->gch.marked ^= WHITEBITS)
  75 #define gray2black(x)   l_setbit((x)->gch.marked, BLACKBIT)
  76
  77 #define valiswhite(x)   (iscollectable(x) && iswhite(gcvalue(x)))
  78
  79 #define luaC_white(g)   cast(lu_byte, (g)->currentwhite & WHITEBITS)
  80
  81
  82 #define luaC_checkGC(L) { \
  83   condhardstacktests(luaD_reallocstack(L, L->stacksize - EXTRA_STACK - 1)); \
  84   if (G(L)->totalbytes >= G(L)->GCthreshold) \
  85         luaC_step(L); }
  86
  87
  88 #define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p)))  \
  89         luaC_barrierf(L,obj2gco(p),gcvalue(v)); }
  90
  91 #define luaC_barriert(L,t,v) { if (valiswhite(v) && isblack(obj2gco(t)))  \
  92         luaC_barrierback(L,t); }
  93
  94 #define luaC_objbarrier(L,p,o)  \
  95         { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
  96                 luaC_barrierf(L,obj2gco(p),obj2gco(o)); }
  97
  98 #define luaC_objbarriert(L,t,o)  \
  99    { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) luaC_barrierback(L,t); }
 100
 101 LUAI_FUNC size_t luaC_separateudata (lua_State *L, int all);
 102 LUAI_FUNC void luaC_callGCTM (lua_State *L);
 103 LUAI_FUNC void luaC_freeall (lua_State *L);
 104 LUAI_FUNC void luaC_step (lua_State *L);
 105 LUAI_FUNC void luaC_fullgc (lua_State *L);
 106 LUAI_FUNC void luaC_link (lua_State *L, GCObject *o, lu_byte tt);
 107 LUAI_FUNC void luaC_linkupval (lua_State *L, UpVal *uv);
 108 LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v);
 109 LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t);
 110
 111
 112 #endif