mirror of
https://github.com/lua/lua
synced 2024-11-22 12:51:30 +03:00
f849885a4b
- Macro 'gray2black' was renamed 'nw2black' (Non-White to black), as it was already being used on objects that could be already black. - Macros 'white2gray' and 'black2gray' were unified in 'set2gray'; no reason to have two macros when one will do and, again, 'black2gray' was already being used on objects that could be already gray. Moreover, macros 'maskcolors' and 'maskgcbits' were negated to have ones in the described bits, instead of zeros. (This naming seems more intuitive.)
190 lines
5.9 KiB
C
190 lines
5.9 KiB
C
/*
|
|
** $Id: lgc.h $
|
|
** 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. (Open
|
|
** upvalues are an exception to this rule.) 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 GCSenteratomic 1
|
|
#define GCSatomic 2
|
|
#define GCSswpallgc 3
|
|
#define GCSswpfinobj 4
|
|
#define GCSswptobefnz 5
|
|
#define GCSswpend 6
|
|
#define GCScallfin 7
|
|
#define GCSpause 8
|
|
|
|
|
|
#define issweepphase(g) \
|
|
(GCSswpallgc <= (g)->gcstate && (g)->gcstate <= GCSswpend)
|
|
|
|
|
|
/*
|
|
** macro to tell when main invariant (white objects cannot point to black
|
|
** ones) must be kept. During a 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.
|
|
*/
|
|
|
|
#define keepinvariant(g) ((g)->gcstate <= GCSatomic)
|
|
|
|
|
|
/*
|
|
** some useful bit tricks
|
|
*/
|
|
#define resetbits(x,m) ((x) &= cast_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. First three bits are
|
|
** used for object "age" in generational mode. Last bit is used
|
|
** by tests.
|
|
*/
|
|
#define WHITE0BIT 3 /* object is white (type 0) */
|
|
#define WHITE1BIT 4 /* object is white (type 1) */
|
|
#define BLACKBIT 5 /* object is black */
|
|
#define FINALIZEDBIT 6 /* object has been marked for finalization */
|
|
|
|
#define TESTBIT 7
|
|
|
|
|
|
|
|
#define WHITEBITS bit2mask(WHITE0BIT, WHITE1BIT)
|
|
|
|
|
|
#define iswhite(x) testbits((x)->marked, WHITEBITS)
|
|
#define isblack(x) testbit((x)->marked, BLACKBIT)
|
|
#define isgray(x) /* neither white nor black */ \
|
|
(!testbits((x)->marked, WHITEBITS | bitmask(BLACKBIT)))
|
|
|
|
#define tofinalize(x) testbit((x)->marked, FINALIZEDBIT)
|
|
|
|
#define otherwhite(g) ((g)->currentwhite ^ WHITEBITS)
|
|
#define isdeadm(ow,m) ((m) & (ow))
|
|
#define isdead(g,v) isdeadm(otherwhite(g), (v)->marked)
|
|
|
|
#define changewhite(x) ((x)->marked ^= WHITEBITS)
|
|
#define nw2black(x) \
|
|
check_exp(!iswhite(x), l_setbit((x)->marked, BLACKBIT))
|
|
|
|
#define luaC_white(g) cast_byte((g)->currentwhite & WHITEBITS)
|
|
|
|
|
|
/* object age in generational mode */
|
|
#define G_NEW 0 /* created in current cycle */
|
|
#define G_SURVIVAL 1 /* created in previous cycle */
|
|
#define G_OLD0 2 /* marked old by frw. barrier in this cycle */
|
|
#define G_OLD1 3 /* first full cycle as old */
|
|
#define G_OLD 4 /* really old object (not to be visited) */
|
|
#define G_TOUCHED1 5 /* old object touched this cycle */
|
|
#define G_TOUCHED2 6 /* old object touched in previous cycle */
|
|
|
|
#define AGEBITS 7 /* all age bits (111) */
|
|
|
|
#define getage(o) ((o)->marked & AGEBITS)
|
|
#define setage(o,a) ((o)->marked = cast_byte(((o)->marked & (~AGEBITS)) | a))
|
|
#define isold(o) (getage(o) > G_SURVIVAL)
|
|
|
|
#define changeage(o,f,t) \
|
|
check_exp(getage(o) == (f), (o)->marked ^= ((f)^(t)))
|
|
|
|
|
|
/* Default Values for GC parameters */
|
|
#define LUAI_GENMAJORMUL 100
|
|
#define LUAI_GENMINORMUL 20
|
|
|
|
/* wait memory to double before starting new cycle */
|
|
#define LUAI_GCPAUSE 200
|
|
|
|
/*
|
|
** some gc parameters are stored divided by 4 to allow a maximum value
|
|
** up to 1023 in a 'lu_byte'.
|
|
*/
|
|
#define getgcparam(p) ((p) * 4)
|
|
#define setgcparam(p,v) ((p) = (v) / 4)
|
|
|
|
#define LUAI_GCMUL 100
|
|
|
|
/* how much to allocate before next GC step (log2) */
|
|
#define LUAI_GCSTEPSIZE 13 /* 8 KB */
|
|
|
|
|
|
/*
|
|
** Check whether the declared GC mode is generational. While in
|
|
** generational mode, the collector can go temporarily to incremental
|
|
** mode to improve performance. This is signaled by 'g->lastatomic != 0'.
|
|
*/
|
|
#define isdecGCmodegen(g) (g->gckind == KGC_GEN || g->lastatomic != 0)
|
|
|
|
/*
|
|
** Does one step of collection when debt becomes positive. 'pre'/'pos'
|
|
** allows some adjustments to be done only when needed. macro
|
|
** 'condchangemem' is used only for heavy tests (forcing a full
|
|
** GC cycle on every opportunity)
|
|
*/
|
|
#define luaC_condGC(L,pre,pos) \
|
|
{ if (G(L)->GCdebt > 0) { pre; luaC_step(L); pos;}; \
|
|
condchangemem(L,pre,pos); }
|
|
|
|
/* more often than not, 'pre'/'pos' are empty */
|
|
#define luaC_checkGC(L) luaC_condGC(L,(void)0,(void)0)
|
|
|
|
|
|
#define luaC_barrier(L,p,v) ( \
|
|
(iscollectable(v) && isblack(p) && iswhite(gcvalue(v))) ? \
|
|
luaC_barrier_(L,obj2gco(p),gcvalue(v)) : cast_void(0))
|
|
|
|
#define luaC_barrierback(L,p,v) ( \
|
|
(iscollectable(v) && isblack(p) && iswhite(gcvalue(v))) ? \
|
|
luaC_barrierback_(L,p) : cast_void(0))
|
|
|
|
#define luaC_objbarrier(L,p,o) ( \
|
|
(isblack(p) && iswhite(o)) ? \
|
|
luaC_barrier_(L,obj2gco(p),obj2gco(o)) : cast_void(0))
|
|
|
|
LUAI_FUNC void luaC_fix (lua_State *L, GCObject *o);
|
|
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);
|
|
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_checkfinalizer (lua_State *L, GCObject *o, Table *mt);
|
|
LUAI_FUNC void luaC_changemode (lua_State *L, int newmode);
|
|
|
|
|
|
#endif
|