mikepaul-LuaJIT/src/lj_gc.h

/*
** Garbage collector.
** Copyright (C) 2005-2010 Mike Pall. See Copyright Notice in luajit.h
*/

#ifndef _LJ_GC_H
#define _LJ_GC_H

#include "lj_obj.h"

/* Garbage collector states. Order matters. */
enum {
  GCSpause, GCSpropagate, GCSatomic, GCSsweepstring, GCSsweep, GCSfinalize
};

/* Bitmasks for marked field of GCobj. */
#define LJ_GC_WHITE0	0x01
#define LJ_GC_WHITE1	0x02
#define LJ_GC_BLACK	0x04
#define LJ_GC_FINALIZED	0x08
#define LJ_GC_WEAKKEY	0x08
#define LJ_GC_WEAKVAL	0x10
#define LJ_GC_FIXED	0x20
#define LJ_GC_SFIXED	0x40

#define LJ_GC_WHITES	(LJ_GC_WHITE0 | LJ_GC_WHITE1)
#define LJ_GC_COLORS	(LJ_GC_WHITES | LJ_GC_BLACK)
#define LJ_GC_WEAK	(LJ_GC_WEAKKEY | LJ_GC_WEAKVAL)

/* Macros to test and set GCobj colors. */
#define iswhite(x)	((x)->gch.marked & LJ_GC_WHITES)
#define isblack(x)	((x)->gch.marked & LJ_GC_BLACK)
#define isgray(x)	(!((x)->gch.marked & (LJ_GC_BLACK|LJ_GC_WHITES)))
#define tviswhite(x)	(tvisgcv(x) && iswhite(gcV(x)))
#define otherwhite(g)	(g->gc.currentwhite ^ LJ_GC_WHITES)
#define isdead(g, v)	((v)->gch.marked & otherwhite(g) & LJ_GC_WHITES)

#define curwhite(g)	((g)->gc.currentwhite & LJ_GC_WHITES)
#define newwhite(g, x)	(obj2gco(x)->gch.marked = (uint8_t)curwhite(g))
#define flipwhite(x)	((x)->gch.marked ^= LJ_GC_WHITES)
#define fixstring(s)	((s)->marked |= LJ_GC_FIXED)

/* Collector. */
LJ_FUNC size_t lj_gc_separateudata(global_State *g, int all);
LJ_FUNC void lj_gc_finalizeudata(lua_State *L);
LJ_FUNC void lj_gc_freeall(global_State *g);
LJ_FUNCA int LJ_FASTCALL lj_gc_step(lua_State *L);
LJ_FUNCA void LJ_FASTCALL lj_gc_step_fixtop(lua_State *L);
#if LJ_HASJIT
LJ_FUNC void LJ_FASTCALL lj_gc_step_jit(lua_State *L, MSize steps);
#endif
LJ_FUNC void lj_gc_fullgc(lua_State *L);

/* GC check: drive collector forward if the GC threshold has been reached. */
#define lj_gc_check(L) \
  { if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) \
      lj_gc_step(L); }
#define lj_gc_check_fixtop(L) \
  { if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) \
      lj_gc_step_fixtop(L); }

/* Write barriers. */
LJ_FUNC void lj_gc_barrierback(global_State *g, GCtab *t);
LJ_FUNC void lj_gc_barrierf(global_State *g, GCobj *o, GCobj *v);
LJ_FUNCA void LJ_FASTCALL lj_gc_barrieruv(global_State *g, TValue *tv);
LJ_FUNC void lj_gc_closeuv(global_State *g, GCupval *uv);
#if LJ_HASJIT
LJ_FUNC void lj_gc_barriertrace(global_State *g, void *T);
#endif

/* Barrier for stores to table objects. TValue and GCobj variant. */
#define lj_gc_barriert(L, t, tv) \
  { if (tviswhite(tv) && isblack(obj2gco(t))) \
      lj_gc_barrierback(G(L), (t)); }
#define lj_gc_objbarriert(L, t, o)  \
  { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) \
      lj_gc_barrierback(G(L), (t)); }

/* Barrier for stores to any other object. TValue and GCobj variant. */
#define lj_gc_barrier(L, p, tv) \
  { if (tviswhite(tv) && isblack(obj2gco(p))) \
      lj_gc_barrierf(G(L), obj2gco(p), gcV(tv)); }
#define lj_gc_objbarrier(L, p, o) \
  { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
      lj_gc_barrierf(G(L), obj2gco(p), obj2gco(o)); }

/* Allocator. */
LJ_FUNC void *lj_mem_realloc(lua_State *L, void *p, MSize osz, MSize nsz);
LJ_FUNC void *lj_mem_newgco(lua_State *L, MSize size);
LJ_FUNC void *lj_mem_grow(lua_State *L, void *p,
			  MSize *szp, MSize lim, MSize esz);

#define lj_mem_new(L, s)	lj_mem_realloc(L, NULL, 0, (s))
#define lj_mem_free(g, p, osize) \
  (g->gc.total -= (MSize)(osize), g->allocf(g->allocd, (p), (osize), 0))

#define lj_mem_newvec(L, n, t)	((t *)lj_mem_new(L, (MSize)((n)*sizeof(t))))
#define lj_mem_reallocvec(L, p, on, n, t) \
  ((p) = (t *)lj_mem_realloc(L, p, (on)*sizeof(t), (MSize)((n)*sizeof(t))))
#define lj_mem_growvec(L, p, n, m, t) \
  ((p) = (t *)lj_mem_grow(L, (p), &(n), (m), (MSize)sizeof(t)))
#define lj_mem_freevec(g, p, n, t)	lj_mem_free(g, (p), (n)*sizeof(t))

#define lj_mem_newobj(L, t)	((t *)lj_mem_newgco(L, sizeof(t)))
#define lj_mem_newt(L, s, t)	((t *)lj_mem_new(L, (s)))
#define lj_mem_freet(g, p)	lj_mem_free(g, (p), sizeof(*(p)))

#endif