diff options
Diffstat (limited to 'lua/lgc.h')
| -rw-r--r-- | lua/lgc.h | 145 |
1 files changed, 87 insertions, 58 deletions
@@ -1,5 +1,5 @@ /* -** $Id: lgc.h,v 2.15.1.1 2007/12/27 13:02:25 roberto Exp $ +** $Id: lgc.h,v 2.52 2011/10/03 17:54:25 roberto Exp $ ** Garbage Collector ** See Copyright Notice in lua.h */ @@ -9,65 +9,89 @@ #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 GCSpause 0 -#define GCSpropagate 1 +#define GCSpropagate 0 +#define GCSatomic 1 #define GCSsweepstring 2 -#define GCSsweep 3 -#define GCSfinalize 4 +#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) + /* -** some userful bit tricks +** 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 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))) -#define test2bits(x,b1,b2) testbits(x, (bit2mask(b1, b2))) - +#define keepinvariant(g) (isgenerational(g) || g->gcstate <= GCSatomic) /* -** Layout for bit use in `marked' field: -** bit 0 - object is white (type 0) -** bit 1 - object is white (type 1) -** bit 2 - object is black -** bit 3 - for userdata: has been finalized -** bit 3 - for tables: has weak keys -** bit 4 - for tables: has weak values -** bit 5 - object is fixed (should not be collected) -** bit 6 - object is "super" fixed (only the main thread) +** 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 WHITE0BIT 0 -#define WHITE1BIT 1 -#define BLACKBIT 2 -#define FINALIZEDBIT 3 -#define KEYWEAKBIT 3 -#define VALUEWEAKBIT 4 -#define FIXEDBIT 5 -#define SFIXEDBIT 6 #define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT) -#define iswhite(x) test2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT) +#define iswhite(x) testbits((x)->gch.marked, WHITEBITS) #define isblack(x) testbit((x)->gch.marked, BLACKBIT) -#define isgray(x) (!isblack(x) && !iswhite(x)) +#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 isdead(g,v) ((v)->gch.marked & otherwhite(g) & 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) @@ -77,34 +101,39 @@ #define luaC_white(g) cast(lu_byte, (g)->currentwhite & WHITEBITS) -#define luaC_checkGC(L) { \ - condhardstacktests(luaD_reallocstack(L, L->stacksize - EXTRA_STACK - 1)); \ - if (G(L)->totalbytes >= G(L)->GCthreshold) \ - luaC_step(L); } +#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_barrierf(L,obj2gco(p),gcvalue(v)); } + luaC_barrier_(L,obj2gco(p),gcvalue(v)); } -#define luaC_barriert(L,t,v) { if (valiswhite(v) && isblack(obj2gco(t))) \ - luaC_barrierback(L,t); } +#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_barrierf(L,obj2gco(p),obj2gco(o)); } + luaC_barrier_(L,obj2gco(p),obj2gco(o)); } -#define luaC_objbarriert(L,t,o) \ - { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) luaC_barrierback(L,t); } +#define luaC_objbarrierback(L,p,o) \ + { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) luaC_barrierback_(L,p); } -LUAI_FUNC size_t luaC_separateudata (lua_State *L, int all); -LUAI_FUNC void luaC_callGCTM (lua_State *L); -LUAI_FUNC void luaC_freeall (lua_State *L); -LUAI_FUNC void luaC_step (lua_State *L); -LUAI_FUNC void luaC_fullgc (lua_State *L); -LUAI_FUNC void luaC_link (lua_State *L, GCObject *o, lu_byte tt); -LUAI_FUNC void luaC_linkupval (lua_State *L, UpVal *uv); -LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v); -LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t); +#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 |