| /* |
| ** $Id: lgc.h,v 2.43 2010/06/07 16:55:34 roberto Exp roberto $ |
| ** Garbage Collector |
| ** See Copyright Notice in lua.h |
| */ |
| |
| #ifndef lgc_h |
| #define lgc_h |
| |
| |
| #include "lobject.h" |
| #include "lstate.h" |
| |
| /* |
| ** Collectable objects may have one of three colors: white, which |
| ** means the object is not marked; gray, which means the |
| ** object is marked, but its references may be not marked; and |
| ** black, which means that the object and all its references are marked. |
| ** The main invariant of the garbage collector, while marking objects, |
| ** is that a black object can never point to a white one. Moreover, |
| ** any gray object must be in a "gray list" (gray, grayagain, weak, |
| ** allweak, ephemeron) so that it can be visited again before finishing |
| ** the collection cycle. These lists have no meaning when the invariant |
| ** is not being enforced (e.g., sweep phase). |
| */ |
| |
| |
| /* |
| ** Possible states of the Garbage Collector |
| */ |
| #define GCSpropagate 0 |
| #define GCSatomic 1 |
| #define GCSsweepstring 2 |
| #define GCSsweepudata 3 |
| #define GCSsweep 4 |
| #define GCSpause 5 |
| |
| |
| #define issweepphase(g) \ |
| (GCSsweepstring <= (g)->gcstate && (g)->gcstate <= GCSsweep) |
| |
| #define isgenerational(g) ((g)->gckind == KGC_GEN) |
| |
| /* |
| ** macro to tell when main invariant (white objects cannot point to black |
| ** ones) must be kept. During a non-generational collection, the sweep |
| ** phase may break the invariant, as objects turned white may point to |
| ** still-black objects. The invariant is restored when sweep ends and |
| ** all objects are white again. During a generational collection, the |
| ** invariant must be kept all times. |
| */ |
| #define keepinvariant(g) (isgenerational(g) || g->gcstate <= GCSatomic) |
| |
| |
| #define gcstopped(g) ((g)->GCdebt == MIN_LMEM) |
| #define stopgc(g) ((g)->GCdebt = MIN_LMEM) |
| |
| |
| /* |
| ** some useful bit tricks |
| */ |
| #define resetbits(x,m) ((x) &= cast(lu_byte, ~(m))) |
| #define setbits(x,m) ((x) |= (m)) |
| #define testbits(x,m) ((x) & (m)) |
| #define bitmask(b) (1<<(b)) |
| #define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2)) |
| #define l_setbit(x,b) setbits(x, bitmask(b)) |
| #define resetbit(x,b) resetbits(x, bitmask(b)) |
| #define testbit(x,b) testbits(x, bitmask(b)) |
| #define set2bits(x,b1,b2) setbits(x, (bit2mask(b1, b2))) |
| #define reset2bits(x,b1,b2) resetbits(x, (bit2mask(b1, b2))) |
| |
| |
| |
| /* Layout for bit use in `marked' field: */ |
| #define WHITE0BIT 0 /* object is white (type 0) */ |
| #define WHITE1BIT 1 /* object is white (type 1) */ |
| #define BLACKBIT 2 /* object is black */ |
| #define FINALIZEDBIT 3 /* for userdata: has been finalized */ |
| #define SEPARATED 4 /* " ": it's in 'udgc' list or in 'tobefnz' */ |
| #define FIXEDBIT 5 /* object is fixed (should not be collected) */ |
| #define OLDBIT 6 /* object is old (only in generational mode) */ |
| /* bit 7 is currently used by tests (luaL_checkmemory) */ |
| |
| #define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT) |
| |
| |
| #define iswhite(x) testbits((x)->gch.marked, WHITEBITS) |
| #define isblack(x) testbit((x)->gch.marked, BLACKBIT) |
| #define isgray(x) /* neither white nor black */ \ |
| (!testbits((x)->gch.marked, WHITEBITS | bitmask(BLACKBIT))) |
| |
| #define isold(x) testbit((x)->gch.marked, OLDBIT) |
| |
| /* MOVE OLD rule: whenever an object is moved to the beginning of |
| a GC list, its old bit must be cleared */ |
| #define resetoldbit(o) resetbit((o)->gch.marked, OLDBIT) |
| |
| #define otherwhite(g) (g->currentwhite ^ WHITEBITS) |
| #define isdeadm(ow,m) (!(((m) ^ WHITEBITS) & (ow))) |
| #define isdead(g,v) isdeadm(otherwhite(g), (v)->gch.marked) |
| |
| #define changewhite(x) ((x)->gch.marked ^= WHITEBITS) |
| #define gray2black(x) l_setbit((x)->gch.marked, BLACKBIT) |
| |
| #define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x))) |
| |
| #define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS) |
| |
| |
| #define luaC_checkGC(L) {condchangemem(L); if (G(L)->GCdebt > 0) luaC_step(L);} |
| |
| |
| #define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \ |
| luaC_barrier_(L,obj2gco(p),gcvalue(v)); } |
| |
| #define luaC_barrierback(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p))) \ |
| luaC_barrierback_(L,p); } |
| |
| #define luaC_objbarrier(L,p,o) \ |
| { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \ |
| luaC_barrier_(L,obj2gco(p),obj2gco(o)); } |
| |
| #define luaC_objbarrierback(L,p,o) \ |
| { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) luaC_barrierback_(L,p); } |
| |
| #define luaC_barrierproto(L,p,c) \ |
| { if (isblack(obj2gco(p))) luaC_barrierproto_(L,p,c); } |
| |
| LUAI_FUNC void luaC_separateudata (lua_State *L, int all); |
| LUAI_FUNC void luaC_freeallobjects (lua_State *L); |
| LUAI_FUNC void luaC_step (lua_State *L); |
| LUAI_FUNC void luaC_runtilstate (lua_State *L, int statesmask); |
| LUAI_FUNC void luaC_fullgc (lua_State *L, int isemergency); |
| LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz, |
| GCObject **list, int offset); |
| LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v); |
| LUAI_FUNC void luaC_barrierback_ (lua_State *L, GCObject *o); |
| LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c); |
| LUAI_FUNC void luaC_checkfinalizer (lua_State *L, Udata *u); |
| LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv); |
| LUAI_FUNC void luaC_changemode (lua_State *L, int mode); |
| |
| #endif |