1eda14cbcSMatt Macy /* 2eda14cbcSMatt Macy ** $Id: lgc.h,v 2.58.1.1 2013/04/12 18:48:47 roberto Exp $ 3eda14cbcSMatt Macy ** Garbage Collector 4eda14cbcSMatt Macy ** See Copyright Notice in lua.h 5eda14cbcSMatt Macy */ 6eda14cbcSMatt Macy 7eda14cbcSMatt Macy #ifndef lgc_h 8eda14cbcSMatt Macy #define lgc_h 9eda14cbcSMatt Macy 10eda14cbcSMatt Macy 11eda14cbcSMatt Macy #include "lobject.h" 12eda14cbcSMatt Macy #include "lstate.h" 13eda14cbcSMatt Macy 14eda14cbcSMatt Macy /* 15eda14cbcSMatt Macy ** Collectable objects may have one of three colors: white, which 16eda14cbcSMatt Macy ** means the object is not marked; gray, which means the 17eda14cbcSMatt Macy ** object is marked, but its references may be not marked; and 18eda14cbcSMatt Macy ** black, which means that the object and all its references are marked. 19eda14cbcSMatt Macy ** The main invariant of the garbage collector, while marking objects, 20eda14cbcSMatt Macy ** is that a black object can never point to a white one. Moreover, 21eda14cbcSMatt Macy ** any gray object must be in a "gray list" (gray, grayagain, weak, 22eda14cbcSMatt Macy ** allweak, ephemeron) so that it can be visited again before finishing 23eda14cbcSMatt Macy ** the collection cycle. These lists have no meaning when the invariant 24eda14cbcSMatt Macy ** is not being enforced (e.g., sweep phase). 25eda14cbcSMatt Macy */ 26eda14cbcSMatt Macy 27eda14cbcSMatt Macy 28eda14cbcSMatt Macy 29eda14cbcSMatt Macy /* how much to allocate before next GC step */ 30eda14cbcSMatt Macy #if !defined(GCSTEPSIZE) 31eda14cbcSMatt Macy /* ~100 small strings */ 32eda14cbcSMatt Macy #define GCSTEPSIZE (cast_int(100 * sizeof(TString))) 33eda14cbcSMatt Macy #endif 34eda14cbcSMatt Macy 35eda14cbcSMatt Macy 36eda14cbcSMatt Macy /* 37eda14cbcSMatt Macy ** Possible states of the Garbage Collector 38eda14cbcSMatt Macy */ 39eda14cbcSMatt Macy #define GCSpropagate 0 40eda14cbcSMatt Macy #define GCSatomic 1 41eda14cbcSMatt Macy #define GCSsweepstring 2 42eda14cbcSMatt Macy #define GCSsweepudata 3 43eda14cbcSMatt Macy #define GCSsweep 4 44eda14cbcSMatt Macy #define GCSpause 5 45eda14cbcSMatt Macy 46eda14cbcSMatt Macy 47eda14cbcSMatt Macy #define issweepphase(g) \ 48eda14cbcSMatt Macy (GCSsweepstring <= (g)->gcstate && (g)->gcstate <= GCSsweep) 49eda14cbcSMatt Macy 50eda14cbcSMatt Macy #define isgenerational(g) ((g)->gckind == KGC_GEN) 51eda14cbcSMatt Macy 52eda14cbcSMatt Macy /* 53eda14cbcSMatt Macy ** macros to tell when main invariant (white objects cannot point to black 54eda14cbcSMatt Macy ** ones) must be kept. During a non-generational collection, the sweep 55eda14cbcSMatt Macy ** phase may break the invariant, as objects turned white may point to 56eda14cbcSMatt Macy ** still-black objects. The invariant is restored when sweep ends and 57eda14cbcSMatt Macy ** all objects are white again. During a generational collection, the 58eda14cbcSMatt Macy ** invariant must be kept all times. 59eda14cbcSMatt Macy */ 60eda14cbcSMatt Macy 61eda14cbcSMatt Macy #define keepinvariant(g) (isgenerational(g) || g->gcstate <= GCSatomic) 62eda14cbcSMatt Macy 63eda14cbcSMatt Macy 64eda14cbcSMatt Macy /* 65eda14cbcSMatt Macy ** Outside the collector, the state in generational mode is kept in 66eda14cbcSMatt Macy ** 'propagate', so 'keepinvariant' is always true. 67eda14cbcSMatt Macy */ 68eda14cbcSMatt Macy #define keepinvariantout(g) \ 69eda14cbcSMatt Macy check_exp(g->gcstate == GCSpropagate || !isgenerational(g), \ 70eda14cbcSMatt Macy g->gcstate <= GCSatomic) 71eda14cbcSMatt Macy 72eda14cbcSMatt Macy 73eda14cbcSMatt Macy /* 74eda14cbcSMatt Macy ** some useful bit tricks 75eda14cbcSMatt Macy */ 76eda14cbcSMatt Macy #define resetbits(x,m) ((x) &= cast(lu_byte, ~(m))) 77eda14cbcSMatt Macy #define setbits(x,m) ((x) |= (m)) 78eda14cbcSMatt Macy #define testbits(x,m) ((x) & (m)) 79eda14cbcSMatt Macy #define bitmask(b) (1<<(b)) 80eda14cbcSMatt Macy #define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2)) 81eda14cbcSMatt Macy #define l_setbit(x,b) setbits(x, bitmask(b)) 82eda14cbcSMatt Macy #define resetbit(x,b) resetbits(x, bitmask(b)) 83eda14cbcSMatt Macy #define testbit(x,b) testbits(x, bitmask(b)) 84eda14cbcSMatt Macy 85eda14cbcSMatt Macy 86eda14cbcSMatt Macy /* Layout for bit use in `marked' field: */ 87eda14cbcSMatt Macy #define WHITE0BIT 0 /* object is white (type 0) */ 88eda14cbcSMatt Macy #define WHITE1BIT 1 /* object is white (type 1) */ 89eda14cbcSMatt Macy #define BLACKBIT 2 /* object is black */ 90eda14cbcSMatt Macy #define FINALIZEDBIT 3 /* object has been separated for finalization */ 91eda14cbcSMatt Macy #define SEPARATED 4 /* object is in 'finobj' list or in 'tobefnz' */ 92eda14cbcSMatt Macy #define FIXEDBIT 5 /* object is fixed (should not be collected) */ 93eda14cbcSMatt Macy #define OLDBIT 6 /* object is old (only in generational mode) */ 94eda14cbcSMatt Macy /* bit 7 is currently used by tests (luaL_checkmemory) */ 95eda14cbcSMatt Macy 96eda14cbcSMatt Macy #define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT) 97eda14cbcSMatt Macy 98eda14cbcSMatt Macy 99eda14cbcSMatt Macy #define iswhite(x) testbits((x)->gch.marked, WHITEBITS) 100eda14cbcSMatt Macy #define isblack(x) testbit((x)->gch.marked, BLACKBIT) 101eda14cbcSMatt Macy #define isgray(x) /* neither white nor black */ \ 102eda14cbcSMatt Macy (!testbits((x)->gch.marked, WHITEBITS | bitmask(BLACKBIT))) 103eda14cbcSMatt Macy 104eda14cbcSMatt Macy #define isold(x) testbit((x)->gch.marked, OLDBIT) 105eda14cbcSMatt Macy 106eda14cbcSMatt Macy /* MOVE OLD rule: whenever an object is moved to the beginning of 107eda14cbcSMatt Macy a GC list, its old bit must be cleared */ 108eda14cbcSMatt Macy #define resetoldbit(o) resetbit((o)->gch.marked, OLDBIT) 109eda14cbcSMatt Macy 110eda14cbcSMatt Macy #define otherwhite(g) (g->currentwhite ^ WHITEBITS) 111eda14cbcSMatt Macy #define isdeadm(ow,m) (!(((m) ^ WHITEBITS) & (ow))) 112eda14cbcSMatt Macy #define isdead(g,v) isdeadm(otherwhite(g), (v)->gch.marked) 113eda14cbcSMatt Macy 114eda14cbcSMatt Macy #define changewhite(x) ((x)->gch.marked ^= WHITEBITS) 115eda14cbcSMatt Macy #define gray2black(x) l_setbit((x)->gch.marked, BLACKBIT) 116eda14cbcSMatt Macy 117eda14cbcSMatt Macy #define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x))) 118eda14cbcSMatt Macy 119eda14cbcSMatt Macy #define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS) 120eda14cbcSMatt Macy 121eda14cbcSMatt Macy 122eda14cbcSMatt Macy #define luaC_condGC(L,c) \ 123*15f0b8c3SMartin Matuska {if (G(L)->GCdebt > 0) {c;} condchangemem(L);} 124eda14cbcSMatt Macy #define luaC_checkGC(L) luaC_condGC(L, luaC_step(L);) 125eda14cbcSMatt Macy 126eda14cbcSMatt Macy 127eda14cbcSMatt Macy #define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \ 128eda14cbcSMatt Macy luaC_barrier_(L,obj2gco(p),gcvalue(v)); } 129eda14cbcSMatt Macy 130eda14cbcSMatt Macy #define luaC_barrierback(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \ 131eda14cbcSMatt Macy luaC_barrierback_(L,p); } 132eda14cbcSMatt Macy 133eda14cbcSMatt Macy #define luaC_objbarrier(L,p,o) \ 134eda14cbcSMatt Macy { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \ 135eda14cbcSMatt Macy luaC_barrier_(L,obj2gco(p),obj2gco(o)); } 136eda14cbcSMatt Macy 137eda14cbcSMatt Macy #define luaC_objbarrierback(L,p,o) \ 138eda14cbcSMatt Macy { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) luaC_barrierback_(L,p); } 139eda14cbcSMatt Macy 140eda14cbcSMatt Macy #define luaC_barrierproto(L,p,c) \ 141eda14cbcSMatt Macy { if (isblack(obj2gco(p))) luaC_barrierproto_(L,p,c); } 142eda14cbcSMatt Macy 143eda14cbcSMatt Macy LUAI_FUNC void luaC_freeallobjects (lua_State *L); 144eda14cbcSMatt Macy LUAI_FUNC void luaC_step (lua_State *L); 145eda14cbcSMatt Macy LUAI_FUNC void luaC_forcestep (lua_State *L); 146eda14cbcSMatt Macy LUAI_FUNC void luaC_runtilstate (lua_State *L, int statesmask); 147eda14cbcSMatt Macy LUAI_FUNC void luaC_fullgc (lua_State *L, int isemergency); 148eda14cbcSMatt Macy LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz, 149eda14cbcSMatt Macy GCObject **list, int offset); 150eda14cbcSMatt Macy LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v); 151eda14cbcSMatt Macy LUAI_FUNC void luaC_barrierback_ (lua_State *L, GCObject *o); 152eda14cbcSMatt Macy LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c); 153eda14cbcSMatt Macy LUAI_FUNC void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt); 154eda14cbcSMatt Macy LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv); 155eda14cbcSMatt Macy LUAI_FUNC void luaC_changemode (lua_State *L, int mode); 156eda14cbcSMatt Macy 157eda14cbcSMatt Macy #endif 158