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git.zerfleddert.de Git - proxmark3-svn/blob - liblua/lgc.h
2 ** $Id: lgc.h,v 2.58 2012/09/11 12:53:08 roberto Exp $
4 ** See Copyright Notice in lua.h
15 ** Collectable objects may have one of three colors: white, which
16 ** means the object is not marked; gray, which means the
17 ** object is marked, but its references may be not marked; and
18 ** black, which means that the object and all its references are marked.
19 ** The main invariant of the garbage collector, while marking objects,
20 ** is that a black object can never point to a white one. Moreover,
21 ** any gray object must be in a "gray list" (gray, grayagain, weak,
22 ** allweak, ephemeron) so that it can be visited again before finishing
23 ** the collection cycle. These lists have no meaning when the invariant
24 ** is not being enforced (e.g., sweep phase).
29 /* how much to allocate before next GC step */
30 #if !defined(GCSTEPSIZE)
31 /* ~100 small strings */
32 #define GCSTEPSIZE (cast_int(100 * sizeof(TString)))
37 ** Possible states of the Garbage Collector
39 #define GCSpropagate 0
41 #define GCSsweepstring 2
42 #define GCSsweepudata 3
47 #define issweepphase(g) \
48 (GCSsweepstring <= (g)->gcstate && (g)->gcstate <= GCSsweep)
50 #define isgenerational(g) ((g)->gckind == KGC_GEN)
53 ** macros to tell when main invariant (white objects cannot point to black
54 ** ones) must be kept. During a non-generational collection, the sweep
55 ** phase may break the invariant, as objects turned white may point to
56 ** still-black objects. The invariant is restored when sweep ends and
57 ** all objects are white again. During a generational collection, the
58 ** invariant must be kept all times.
61 #define keepinvariant(g) (isgenerational(g) || g->gcstate <= GCSatomic)
65 ** Outside the collector, the state in generational mode is kept in
66 ** 'propagate', so 'keepinvariant' is always true.
68 #define keepinvariantout(g) \
69 check_exp(g->gcstate == GCSpropagate || !isgenerational(g), \
70 g->gcstate <= GCSatomic)
74 ** some useful bit tricks
76 #define resetbits(x,m) ((x) &= cast(lu_byte, ~(m)))
77 #define setbits(x,m) ((x) |= (m))
78 #define testbits(x,m) ((x) & (m))
79 #define bitmask(b) (1<<(b))
80 #define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2))
81 #define l_setbit(x,b) setbits(x, bitmask(b))
82 #define resetbit(x,b) resetbits(x, bitmask(b))
83 #define testbit(x,b) testbits(x, bitmask(b))
86 /* Layout for bit use in `marked' field: */
87 #define WHITE0BIT 0 /* object is white (type 0) */
88 #define WHITE1BIT 1 /* object is white (type 1) */
89 #define BLACKBIT 2 /* object is black */
90 #define FINALIZEDBIT 3 /* object has been separated for finalization */
91 #define SEPARATED 4 /* object is in 'finobj' list or in 'tobefnz' */
92 #define FIXEDBIT 5 /* object is fixed (should not be collected) */
93 #define OLDBIT 6 /* object is old (only in generational mode) */
94 /* bit 7 is currently used by tests (luaL_checkmemory) */
96 #define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT)
99 #define iswhite(x) testbits((x)->gch.marked, WHITEBITS)
100 #define isblack(x) testbit((x)->gch.marked, BLACKBIT)
101 #define isgray(x) /* neither white nor black */ \
102 (!testbits((x)->gch.marked, WHITEBITS | bitmask(BLACKBIT)))
104 #define isold(x) testbit((x)->gch.marked, OLDBIT)
106 /* MOVE OLD rule: whenever an object is moved to the beginning of
107 a GC list, its old bit must be cleared */
108 #define resetoldbit(o) resetbit((o)->gch.marked, OLDBIT)
110 #define otherwhite(g) (g->currentwhite ^ WHITEBITS)
111 #define isdeadm(ow,m) (!(((m) ^ WHITEBITS) & (ow)))
112 #define isdead(g,v) isdeadm(otherwhite(g), (v)->gch.marked)
114 #define changewhite(x) ((x)->gch.marked ^= WHITEBITS)
115 #define gray2black(x) l_setbit((x)->gch.marked, BLACKBIT)
117 #define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x)))
119 #define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS)
122 #define luaC_condGC(L,c) \
123 {if (G(L)->GCdebt > 0) {c;}; condchangemem(L);}
124 #define luaC_checkGC(L) luaC_condGC(L, luaC_step(L);)
127 #define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \
128 luaC_barrier_(L,obj2gco(p),gcvalue(v)); }
130 #define luaC_barrierback(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \
131 luaC_barrierback_(L,p); }
133 #define luaC_objbarrier(L,p,o) \
134 { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
135 luaC_barrier_(L,obj2gco(p),obj2gco(o)); }
137 #define luaC_objbarrierback(L,p,o) \
138 { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) luaC_barrierback_(L,p); }
140 #define luaC_barrierproto(L,p,c) \
141 { if (isblack(obj2gco(p))) luaC_barrierproto_(L,p,c); }
143 LUAI_FUNC
void luaC_freeallobjects (lua_State
*L
);
144 LUAI_FUNC
void luaC_step (lua_State
*L
);
145 LUAI_FUNC
void luaC_forcestep (lua_State
*L
);
146 LUAI_FUNC
void luaC_runtilstate (lua_State
*L
, int statesmask
);
147 LUAI_FUNC
void luaC_fullgc (lua_State
*L
, int isemergency
);
148 LUAI_FUNC GCObject
*luaC_newobj (lua_State
*L
, int tt
, size_t sz
,
149 GCObject
**list
, int offset
);
150 LUAI_FUNC
void luaC_barrier_ (lua_State
*L
, GCObject
*o
, GCObject
*v
);
151 LUAI_FUNC
void luaC_barrierback_ (lua_State
*L
, GCObject
*o
);
152 LUAI_FUNC
void luaC_barrierproto_ (lua_State
*L
, Proto
*p
, Closure
*c
);
153 LUAI_FUNC
void luaC_checkfinalizer (lua_State
*L
, GCObject
*o
, Table
*mt
);
154 LUAI_FUNC
void luaC_checkupvalcolor (global_State
*g
, UpVal
*uv
);
155 LUAI_FUNC
void luaC_changemode (lua_State
*L
, int mode
);