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Diffstat (limited to 'module/lua/lgc.h')
| -rw-r--r-- | module/lua/lgc.h | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/module/lua/lgc.h b/module/lua/lgc.h new file mode 100644 index 000000000..34097a45e --- /dev/null +++ b/module/lua/lgc.h @@ -0,0 +1,159 @@ +/* BEGIN CSTYLED */ +/* +** $Id: lgc.h,v 2.58.1.1 2013/04/12 18:48:47 roberto Exp $ +** 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). +*/ + + + +/* how much to allocate before next GC step */ +#if !defined(GCSTEPSIZE) +/* ~100 small strings */ +#define GCSTEPSIZE (cast_int(100 * sizeof(TString))) +#endif + + +/* +** 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) + +/* +** macros 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) + + +/* +** Outside the collector, the state in generational mode is kept in +** 'propagate', so 'keepinvariant' is always true. +*/ +#define keepinvariantout(g) \ + check_exp(g->gcstate == GCSpropagate || !isgenerational(g), \ + g->gcstate <= GCSatomic) + + +/* +** 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)) + + +/* 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 /* object has been separated for finalization */ +#define SEPARATED 4 /* object is in 'finobj' 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_condGC(L,c) \ + {if (G(L)->GCdebt > 0) {c;}; condchangemem(L);} +#define luaC_checkGC(L) luaC_condGC(L, 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_freeallobjects (lua_State *L); +LUAI_FUNC void luaC_step (lua_State *L); +LUAI_FUNC void luaC_forcestep (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, GCObject *o, Table *mt); +LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv); +LUAI_FUNC void luaC_changemode (lua_State *L, int mode); + +#endif +/* END CSTYLED */ |