1*dfc11533SChris Williamson /* 2*dfc11533SChris Williamson ** $Id: lgc.h,v 2.58.1.1 2013/04/12 18:48:47 roberto Exp $ 3*dfc11533SChris Williamson ** Garbage Collector 4*dfc11533SChris Williamson ** See Copyright Notice in lua.h 5*dfc11533SChris Williamson */ 6*dfc11533SChris Williamson 7*dfc11533SChris Williamson #ifndef lgc_h 8*dfc11533SChris Williamson #define lgc_h 9*dfc11533SChris Williamson 10*dfc11533SChris Williamson 11*dfc11533SChris Williamson #include "lobject.h" 12*dfc11533SChris Williamson #include "lstate.h" 13*dfc11533SChris Williamson 14*dfc11533SChris Williamson /* 15*dfc11533SChris Williamson ** Collectable objects may have one of three colors: white, which 16*dfc11533SChris Williamson ** means the object is not marked; gray, which means the 17*dfc11533SChris Williamson ** object is marked, but its references may be not marked; and 18*dfc11533SChris Williamson ** black, which means that the object and all its references are marked. 19*dfc11533SChris Williamson ** The main invariant of the garbage collector, while marking objects, 20*dfc11533SChris Williamson ** is that a black object can never point to a white one. Moreover, 21*dfc11533SChris Williamson ** any gray object must be in a "gray list" (gray, grayagain, weak, 22*dfc11533SChris Williamson ** allweak, ephemeron) so that it can be visited again before finishing 23*dfc11533SChris Williamson ** the collection cycle. These lists have no meaning when the invariant 24*dfc11533SChris Williamson ** is not being enforced (e.g., sweep phase). 25*dfc11533SChris Williamson */ 26*dfc11533SChris Williamson 27*dfc11533SChris Williamson 28*dfc11533SChris Williamson 29*dfc11533SChris Williamson /* how much to allocate before next GC step */ 30*dfc11533SChris Williamson #if !defined(GCSTEPSIZE) 31*dfc11533SChris Williamson /* ~100 small strings */ 32*dfc11533SChris Williamson #define GCSTEPSIZE (cast_int(100 * sizeof(TString))) 33*dfc11533SChris Williamson #endif 34*dfc11533SChris Williamson 35*dfc11533SChris Williamson 36*dfc11533SChris Williamson /* 37*dfc11533SChris Williamson ** Possible states of the Garbage Collector 38*dfc11533SChris Williamson */ 39*dfc11533SChris Williamson #define GCSpropagate 0 40*dfc11533SChris Williamson #define GCSatomic 1 41*dfc11533SChris Williamson #define GCSsweepstring 2 42*dfc11533SChris Williamson #define GCSsweepudata 3 43*dfc11533SChris Williamson #define GCSsweep 4 44*dfc11533SChris Williamson #define GCSpause 5 45*dfc11533SChris Williamson 46*dfc11533SChris Williamson 47*dfc11533SChris Williamson #define issweepphase(g) \ 48*dfc11533SChris Williamson (GCSsweepstring <= (g)->gcstate && (g)->gcstate <= GCSsweep) 49*dfc11533SChris Williamson 50*dfc11533SChris Williamson #define isgenerational(g) ((g)->gckind == KGC_GEN) 51*dfc11533SChris Williamson 52*dfc11533SChris Williamson /* 53*dfc11533SChris Williamson ** macros to tell when main invariant (white objects cannot point to black 54*dfc11533SChris Williamson ** ones) must be kept. During a non-generational collection, the sweep 55*dfc11533SChris Williamson ** phase may break the invariant, as objects turned white may point to 56*dfc11533SChris Williamson ** still-black objects. The invariant is restored when sweep ends and 57*dfc11533SChris Williamson ** all objects are white again. During a generational collection, the 58*dfc11533SChris Williamson ** invariant must be kept all times. 59*dfc11533SChris Williamson */ 60*dfc11533SChris Williamson 61*dfc11533SChris Williamson #define keepinvariant(g) (isgenerational(g) || g->gcstate <= GCSatomic) 62*dfc11533SChris Williamson 63*dfc11533SChris Williamson 64*dfc11533SChris Williamson /* 65*dfc11533SChris Williamson ** Outside the collector, the state in generational mode is kept in 66*dfc11533SChris Williamson ** 'propagate', so 'keepinvariant' is always true. 67*dfc11533SChris Williamson */ 68*dfc11533SChris Williamson #define keepinvariantout(g) \ 69*dfc11533SChris Williamson check_exp(g->gcstate == GCSpropagate || !isgenerational(g), \ 70*dfc11533SChris Williamson g->gcstate <= GCSatomic) 71*dfc11533SChris Williamson 72*dfc11533SChris Williamson 73*dfc11533SChris Williamson /* 74*dfc11533SChris Williamson ** some useful bit tricks 75*dfc11533SChris Williamson */ 76*dfc11533SChris Williamson #define resetbits(x,m) ((x) &= cast(lu_byte, ~(m))) 77*dfc11533SChris Williamson #define setbits(x,m) ((x) |= (m)) 78*dfc11533SChris Williamson #define testbits(x,m) ((x) & (m)) 79*dfc11533SChris Williamson #define bitmask(b) (1<<(b)) 80*dfc11533SChris Williamson #define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2)) 81*dfc11533SChris Williamson #define l_setbit(x,b) setbits(x, bitmask(b)) 82*dfc11533SChris Williamson #define resetbit(x,b) resetbits(x, bitmask(b)) 83*dfc11533SChris Williamson #define testbit(x,b) testbits(x, bitmask(b)) 84*dfc11533SChris Williamson 85*dfc11533SChris Williamson 86*dfc11533SChris Williamson /* Layout for bit use in `marked' field: */ 87*dfc11533SChris Williamson #define WHITE0BIT 0 /* object is white (type 0) */ 88*dfc11533SChris Williamson #define WHITE1BIT 1 /* object is white (type 1) */ 89*dfc11533SChris Williamson #define BLACKBIT 2 /* object is black */ 90*dfc11533SChris Williamson #define FINALIZEDBIT 3 /* object has been separated for finalization */ 91*dfc11533SChris Williamson #define SEPARATED 4 /* object is in 'finobj' list or in 'tobefnz' */ 92*dfc11533SChris Williamson #define FIXEDBIT 5 /* object is fixed (should not be collected) */ 93*dfc11533SChris Williamson #define OLDBIT 6 /* object is old (only in generational mode) */ 94*dfc11533SChris Williamson /* bit 7 is currently used by tests (luaL_checkmemory) */ 95*dfc11533SChris Williamson 96*dfc11533SChris Williamson #define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT) 97*dfc11533SChris Williamson 98*dfc11533SChris Williamson 99*dfc11533SChris Williamson #define iswhite(x) testbits((x)->gch.marked, WHITEBITS) 100*dfc11533SChris Williamson #define isblack(x) testbit((x)->gch.marked, BLACKBIT) 101*dfc11533SChris Williamson #define isgray(x) /* neither white nor black */ \ 102*dfc11533SChris Williamson (!testbits((x)->gch.marked, WHITEBITS | bitmask(BLACKBIT))) 103*dfc11533SChris Williamson 104*dfc11533SChris Williamson #define isold(x) testbit((x)->gch.marked, OLDBIT) 105*dfc11533SChris Williamson 106*dfc11533SChris Williamson /* MOVE OLD rule: whenever an object is moved to the beginning of 107*dfc11533SChris Williamson a GC list, its old bit must be cleared */ 108*dfc11533SChris Williamson #define resetoldbit(o) resetbit((o)->gch.marked, OLDBIT) 109*dfc11533SChris Williamson 110*dfc11533SChris Williamson #define otherwhite(g) (g->currentwhite ^ WHITEBITS) 111*dfc11533SChris Williamson #define isdeadm(ow,m) (!(((m) ^ WHITEBITS) & (ow))) 112*dfc11533SChris Williamson #define isdead(g,v) isdeadm(otherwhite(g), (v)->gch.marked) 113*dfc11533SChris Williamson 114*dfc11533SChris Williamson #define changewhite(x) ((x)->gch.marked ^= WHITEBITS) 115*dfc11533SChris Williamson #define gray2black(x) l_setbit((x)->gch.marked, BLACKBIT) 116*dfc11533SChris Williamson 117*dfc11533SChris Williamson #define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x))) 118*dfc11533SChris Williamson 119*dfc11533SChris Williamson #define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS) 120*dfc11533SChris Williamson 121*dfc11533SChris Williamson 122*dfc11533SChris Williamson #define luaC_condGC(L,c) \ 123*dfc11533SChris Williamson {if (G(L)->GCdebt > 0) {c;}; condchangemem(L);} 124*dfc11533SChris Williamson #define luaC_checkGC(L) luaC_condGC(L, luaC_step(L);) 125*dfc11533SChris Williamson 126*dfc11533SChris Williamson 127*dfc11533SChris Williamson #define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \ 128*dfc11533SChris Williamson luaC_barrier_(L,obj2gco(p),gcvalue(v)); } 129*dfc11533SChris Williamson 130*dfc11533SChris Williamson #define luaC_barrierback(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \ 131*dfc11533SChris Williamson luaC_barrierback_(L,p); } 132*dfc11533SChris Williamson 133*dfc11533SChris Williamson #define luaC_objbarrier(L,p,o) \ 134*dfc11533SChris Williamson { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \ 135*dfc11533SChris Williamson luaC_barrier_(L,obj2gco(p),obj2gco(o)); } 136*dfc11533SChris Williamson 137*dfc11533SChris Williamson #define luaC_objbarrierback(L,p,o) \ 138*dfc11533SChris Williamson { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) luaC_barrierback_(L,p); } 139*dfc11533SChris Williamson 140*dfc11533SChris Williamson #define luaC_barrierproto(L,p,c) \ 141*dfc11533SChris Williamson { if (isblack(obj2gco(p))) luaC_barrierproto_(L,p,c); } 142*dfc11533SChris Williamson 143*dfc11533SChris Williamson LUAI_FUNC void luaC_freeallobjects (lua_State *L); 144*dfc11533SChris Williamson LUAI_FUNC void luaC_step (lua_State *L); 145*dfc11533SChris Williamson LUAI_FUNC void luaC_forcestep (lua_State *L); 146*dfc11533SChris Williamson LUAI_FUNC void luaC_runtilstate (lua_State *L, int statesmask); 147*dfc11533SChris Williamson LUAI_FUNC void luaC_fullgc (lua_State *L, int isemergency); 148*dfc11533SChris Williamson LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz, 149*dfc11533SChris Williamson GCObject **list, int offset); 150*dfc11533SChris Williamson LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v); 151*dfc11533SChris Williamson LUAI_FUNC void luaC_barrierback_ (lua_State *L, GCObject *o); 152*dfc11533SChris Williamson LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c); 153*dfc11533SChris Williamson LUAI_FUNC void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt); 154*dfc11533SChris Williamson LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv); 155*dfc11533SChris Williamson LUAI_FUNC void luaC_changemode (lua_State *L, int mode); 156*dfc11533SChris Williamson 157*dfc11533SChris Williamson #endif 158