--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_gc.h	Thu Jan 22 20:10:30 2026 -0800
@@ -0,0 +1,136 @@
+/*
+** Garbage collector.
+** Copyright (C) 2005-2023 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_CDATA_FIN	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 makewhite(g, x) \
+  ((x)->gch.marked = ((x)->gch.marked & (uint8_t)~LJ_GC_COLORS) | curwhite(g))
+#define flipwhite(x)	((x)->gch.marked ^= LJ_GC_WHITES)
+#define black2gray(x)	((x)->gch.marked &= (uint8_t)~LJ_GC_BLACK)
+#define fixstring(s)	((s)->marked |= LJ_GC_FIXED)
+#define markfinalized(x)	((x)->gch.marked |= LJ_GC_FINALIZED)
+
+/* Collector. */
+LJ_FUNC size_t lj_gc_separateudata(global_State *g, int all);
+LJ_FUNC void lj_gc_finalize_udata(lua_State *L);
+#if LJ_HASFFI
+LJ_FUNC void lj_gc_finalize_cdata(lua_State *L);
+#else
+#define lj_gc_finalize_cdata(L)		UNUSED(L)
+#endif
+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 int LJ_FASTCALL lj_gc_step_jit(global_State *g, 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_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, uint32_t traceno);
+#endif
+
+/* Move the GC propagation frontier back for tables (make it gray again). */
+static LJ_AINLINE void lj_gc_barrierback(global_State *g, GCtab *t)
+{
+  GCobj *o = obj2gco(t);
+  lj_assertG(isblack(o) && !isdead(g, o),
+	     "bad object states for backward barrier");
+  lj_assertG(g->gc.state != GCSfinalize && g->gc.state != GCSpause,
+	     "bad GC state");
+  black2gray(o);
+  setgcrefr(t->gclist, g->gc.grayagain);
+  setgcref(g->gc.grayagain, o);
+}
+
+/* Barrier for stores to table objects. TValue and GCobj variant. */
+#define lj_gc_anybarriert(L, t)  \
+  { if (LJ_UNLIKELY(isblack(obj2gco(t)))) lj_gc_barrierback(G(L), (t)); }
+#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, GCSize osz, GCSize nsz);
+LJ_FUNC void * LJ_FASTCALL lj_mem_newgco(lua_State *L, GCSize 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))
+
+static LJ_AINLINE void lj_mem_free(global_State *g, void *p, size_t osize)
+{
+  g->gc.total -= (GCSize)osize;
+  g->allocf(g->allocd, p, osize, 0);
+}
+
+#define lj_mem_newvec(L, n, t)	((t *)lj_mem_new(L, (GCSize)((n)*sizeof(t))))
+#define lj_mem_reallocvec(L, p, on, n, t) \
+  ((p) = (t *)lj_mem_realloc(L, p, (on)*sizeof(t), (GCSize)((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