src/lj_udata.c

   1 /*
   2 ** Userdata handling.
   3 ** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
   4 */
   5
   6 #define lj_udata_c
   7 #define LUA_CORE
   8
   9 #include "lj_obj.h"
  10 #include "lj_gc.h"
  11 #include "lj_err.h"
  12 #include "lj_udata.h"
  13
  14 GCudata *lj_udata_new(lua_State *L, MSize sz, GCtab *env)
  15 {
  16   GCudata *ud = lj_mem_newt(L, sizeof(GCudata) + sz, GCudata);
  17   global_State *g = G(L);
  18   newwhite(g, ud);  /* Not finalized. */
  19   ud->gct = ~LJ_TUDATA;
  20   ud->udtype = UDTYPE_USERDATA;
  21   ud->len = sz;
  22   /* NOBARRIER: The GCudata is new (marked white). */
  23   setgcrefnull(ud->metatable);
  24   setgcref(ud->env, obj2gco(env));
  25   /* Chain to userdata list (after main thread). */
  26   setgcrefr(ud->nextgc, mainthread(g)->nextgc);
  27   setgcref(mainthread(g)->nextgc, obj2gco(ud));
  28   return ud;
  29 }
  30
  31 void LJ_FASTCALL lj_udata_free(global_State *g, GCudata *ud)
  32 {
  33   lj_mem_free(g, ud, sizeudata(ud));
  34 }
  35
  36 #if LJ_64
  37 void *lj_lightud_intern(lua_State *L, void *p)
  38 {
  39   global_State *g = G(L);
  40   uint64_t u = (uint64_t)p;
  41   uint32_t up = lightudup(u);
  42   uint32_t *segmap = mref(g->gc.lightudseg, uint32_t);
  43   MSize segnum = g->gc.lightudnum;
  44   if (segmap) {
  45     MSize seg;
  46     for (seg = 0; seg <= segnum; seg++)
  47       if (segmap[seg] == up)  /* Fast path. */
  48         return (void *)(((uint64_t)seg << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
  49     segnum++;
  50     /* Leave last segment unused to avoid clash with ITERN key. */
  51     if (segnum >= (1 << LJ_LIGHTUD_BITS_SEG)-1) lj_err_msg(L, LJ_ERR_BADLU);
  52   }
  53   if (!((segnum-1) & segnum) && segnum != 1) {
  54     lj_mem_reallocvec(L, segmap, segnum, segnum ? 2*segnum : 2u, uint32_t);
  55     setmref(g->gc.lightudseg, segmap);
  56   }
  57   g->gc.lightudnum = segnum;
  58   segmap[segnum] = up;
  59   return (void *)(((uint64_t)segnum << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
  60 }
  61 #endif
  62