0,0 → 1,139 |
/* |
** $Id: lgc.h,v 2.52 2011/10/03 17:54:25 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). |
*/ |
|
|
/* |
** 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) |
|
|
/* |
** 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 |