--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/luajit/src/lj_tab.c	Thu Jan 22 20:10:30 2026 -0800
@@ -0,0 +1,693 @@
+/*
+** Table handling.
+** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
+**
+** Major portions taken verbatim or adapted from the Lua interpreter.
+** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
+*/
+
+#define lj_tab_c
+#define LUA_CORE
+
+#include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_err.h"
+#include "lj_tab.h"
+
+/* -- Object hashing ------------------------------------------------------ */
+
+/* Hash an arbitrary key and return its anchor position in the hash table. */
+static Node *hashkey(const GCtab *t, cTValue *key)
+{
+  lj_assertX(!tvisint(key), "attempt to hash integer");
+  if (tvisstr(key))
+    return hashstr(t, strV(key));
+  else if (tvisnum(key))
+    return hashnum(t, key);
+  else if (tvisbool(key))
+    return hashmask(t, boolV(key));
+  else
+    return hashgcref(t, key->gcr);
+  /* Only hash 32 bits of lightuserdata on a 64 bit CPU. Good enough? */
+}
+
+/* -- Table creation and destruction -------------------------------------- */
+
+/* Create new hash part for table. */
+static LJ_AINLINE void newhpart(lua_State *L, GCtab *t, uint32_t hbits)
+{
+  uint32_t hsize;
+  Node *node;
+  lj_assertL(hbits != 0, "zero hash size");
+  if (hbits > LJ_MAX_HBITS)
+    lj_err_msg(L, LJ_ERR_TABOV);
+  hsize = 1u << hbits;
+  node = lj_mem_newvec(L, hsize, Node);
+  setmref(t->node, node);
+  setfreetop(t, node, &node[hsize]);
+  t->hmask = hsize-1;
+}
+
+/*
+** Q: Why all of these copies of t->hmask, t->node etc. to local variables?
+** A: Because alias analysis for C is _really_ tough.
+**    Even state-of-the-art C compilers won't produce good code without this.
+*/
+
+/* Clear hash part of table. */
+static LJ_AINLINE void clearhpart(GCtab *t)
+{
+  uint32_t i, hmask = t->hmask;
+  Node *node = noderef(t->node);
+  lj_assertX(t->hmask != 0, "empty hash part");
+  for (i = 0; i <= hmask; i++) {
+    Node *n = &node[i];
+    setmref(n->next, NULL);
+    setnilV(&n->key);
+    setnilV(&n->val);
+  }
+}
+
+/* Clear array part of table. */
+static LJ_AINLINE void clearapart(GCtab *t)
+{
+  uint32_t i, asize = t->asize;
+  TValue *array = tvref(t->array);
+  for (i = 0; i < asize; i++)
+    setnilV(&array[i]);
+}
+
+/* Create a new table. Note: the slots are not initialized (yet). */
+static GCtab *newtab(lua_State *L, uint32_t asize, uint32_t hbits)
+{
+  GCtab *t;
+  /* First try to colocate the array part. */
+  if (LJ_MAX_COLOSIZE != 0 && asize > 0 && asize <= LJ_MAX_COLOSIZE) {
+    Node *nilnode;
+    lj_assertL((sizeof(GCtab) & 7) == 0, "bad GCtab size");
+    t = (GCtab *)lj_mem_newgco(L, sizetabcolo(asize));
+    t->gct = ~LJ_TTAB;
+    t->nomm = (uint8_t)~0;
+    t->colo = (int8_t)asize;
+    setmref(t->array, (TValue *)((char *)t + sizeof(GCtab)));
+    setgcrefnull(t->metatable);
+    t->asize = asize;
+    t->hmask = 0;
+    nilnode = &G(L)->nilnode;
+    setmref(t->node, nilnode);
+#if LJ_GC64
+    setmref(t->freetop, nilnode);
+#endif
+  } else {  /* Otherwise separately allocate the array part. */
+    Node *nilnode;
+    t = lj_mem_newobj(L, GCtab);
+    t->gct = ~LJ_TTAB;
+    t->nomm = (uint8_t)~0;
+    t->colo = 0;
+    setmref(t->array, NULL);
+    setgcrefnull(t->metatable);
+    t->asize = 0;  /* In case the array allocation fails. */
+    t->hmask = 0;
+    nilnode = &G(L)->nilnode;
+    setmref(t->node, nilnode);
+#if LJ_GC64
+    setmref(t->freetop, nilnode);
+#endif
+    if (asize > 0) {
+      if (asize > LJ_MAX_ASIZE)
+	lj_err_msg(L, LJ_ERR_TABOV);
+      setmref(t->array, lj_mem_newvec(L, asize, TValue));
+      t->asize = asize;
+    }
+  }
+  if (hbits)
+    newhpart(L, t, hbits);
+  return t;
+}
+
+/* Create a new table.
+**
+** IMPORTANT NOTE: The API differs from lua_createtable()!
+**
+** The array size is non-inclusive. E.g. asize=128 creates array slots
+** for 0..127, but not for 128. If you need slots 1..128, pass asize=129
+** (slot 0 is wasted in this case).
+**
+** The hash size is given in hash bits. hbits=0 means no hash part.
+** hbits=1 creates 2 hash slots, hbits=2 creates 4 hash slots and so on.
+*/
+GCtab *lj_tab_new(lua_State *L, uint32_t asize, uint32_t hbits)
+{
+  GCtab *t = newtab(L, asize, hbits);
+  clearapart(t);
+  if (t->hmask > 0) clearhpart(t);
+  return t;
+}
+
+/* The API of this function conforms to lua_createtable(). */
+GCtab *lj_tab_new_ah(lua_State *L, int32_t a, int32_t h)
+{
+  return lj_tab_new(L, (uint32_t)(a > 0 ? a+1 : 0), hsize2hbits(h));
+}
+
+#if LJ_HASJIT
+GCtab * LJ_FASTCALL lj_tab_new1(lua_State *L, uint32_t ahsize)
+{
+  GCtab *t = newtab(L, ahsize & 0xffffff, ahsize >> 24);
+  clearapart(t);
+  if (t->hmask > 0) clearhpart(t);
+  return t;
+}
+#endif
+
+/* Duplicate a table. */
+GCtab * LJ_FASTCALL lj_tab_dup(lua_State *L, const GCtab *kt)
+{
+  GCtab *t;
+  uint32_t asize, hmask;
+  t = newtab(L, kt->asize, kt->hmask > 0 ? lj_fls(kt->hmask)+1 : 0);
+  lj_assertL(kt->asize == t->asize && kt->hmask == t->hmask,
+	     "mismatched size of table and template");
+  t->nomm = 0;  /* Keys with metamethod names may be present. */
+  asize = kt->asize;
+  if (asize > 0) {
+    TValue *array = tvref(t->array);
+    TValue *karray = tvref(kt->array);
+    if (asize < 64) {  /* An inlined loop beats memcpy for < 512 bytes. */
+      uint32_t i;
+      for (i = 0; i < asize; i++)
+	copyTV(L, &array[i], &karray[i]);
+    } else {
+      memcpy(array, karray, asize*sizeof(TValue));
+    }
+  }
+  hmask = kt->hmask;
+  if (hmask > 0) {
+    uint32_t i;
+    Node *node = noderef(t->node);
+    Node *knode = noderef(kt->node);
+    ptrdiff_t d = (char *)node - (char *)knode;
+    setfreetop(t, node, (Node *)((char *)getfreetop(kt, knode) + d));
+    for (i = 0; i <= hmask; i++) {
+      Node *kn = &knode[i];
+      Node *n = &node[i];
+      Node *next = nextnode(kn);
+      /* Don't use copyTV here, since it asserts on a copy of a dead key. */
+      n->val = kn->val; n->key = kn->key;
+      setmref(n->next, next == NULL? next : (Node *)((char *)next + d));
+    }
+  }
+  return t;
+}
+
+/* Clear a table. */
+void LJ_FASTCALL lj_tab_clear(GCtab *t)
+{
+  clearapart(t);
+  if (t->hmask > 0) {
+    Node *node = noderef(t->node);
+    setfreetop(t, node, &node[t->hmask+1]);
+    clearhpart(t);
+  }
+}
+
+/* Free a table. */
+void LJ_FASTCALL lj_tab_free(global_State *g, GCtab *t)
+{
+  if (t->hmask > 0)
+    lj_mem_freevec(g, noderef(t->node), t->hmask+1, Node);
+  if (t->asize > 0 && LJ_MAX_COLOSIZE != 0 && t->colo <= 0)
+    lj_mem_freevec(g, tvref(t->array), t->asize, TValue);
+  if (LJ_MAX_COLOSIZE != 0 && t->colo)
+    lj_mem_free(g, t, sizetabcolo((uint32_t)t->colo & 0x7f));
+  else
+    lj_mem_freet(g, t);
+}
+
+/* -- Table resizing ------------------------------------------------------ */
+
+/* Resize a table to fit the new array/hash part sizes. */
+void lj_tab_resize(lua_State *L, GCtab *t, uint32_t asize, uint32_t hbits)
+{
+  Node *oldnode = noderef(t->node);
+  uint32_t oldasize = t->asize;
+  uint32_t oldhmask = t->hmask;
+  if (asize > oldasize) {  /* Array part grows? */
+    TValue *array;
+    uint32_t i;
+    if (asize > LJ_MAX_ASIZE)
+      lj_err_msg(L, LJ_ERR_TABOV);
+    if (LJ_MAX_COLOSIZE != 0 && t->colo > 0) {
+      /* A colocated array must be separated and copied. */
+      TValue *oarray = tvref(t->array);
+      array = lj_mem_newvec(L, asize, TValue);
+      t->colo = (int8_t)(t->colo | 0x80);  /* Mark as separated (colo < 0). */
+      for (i = 0; i < oldasize; i++)
+	copyTV(L, &array[i], &oarray[i]);
+    } else {
+      array = (TValue *)lj_mem_realloc(L, tvref(t->array),
+			  oldasize*sizeof(TValue), asize*sizeof(TValue));
+    }
+    setmref(t->array, array);
+    t->asize = asize;
+    for (i = oldasize; i < asize; i++)  /* Clear newly allocated slots. */
+      setnilV(&array[i]);
+  }
+  /* Create new (empty) hash part. */
+  if (hbits) {
+    newhpart(L, t, hbits);
+    clearhpart(t);
+  } else {
+    global_State *g = G(L);
+    setmref(t->node, &g->nilnode);
+#if LJ_GC64
+    setmref(t->freetop, &g->nilnode);
+#endif
+    t->hmask = 0;
+  }
+  if (asize < oldasize) {  /* Array part shrinks? */
+    TValue *array = tvref(t->array);
+    uint32_t i;
+    t->asize = asize;  /* Note: This 'shrinks' even colocated arrays. */
+    for (i = asize; i < oldasize; i++)  /* Reinsert old array values. */
+      if (!tvisnil(&array[i]))
+	copyTV(L, lj_tab_setinth(L, t, (int32_t)i), &array[i]);
+    /* Physically shrink only separated arrays. */
+    if (LJ_MAX_COLOSIZE != 0 && t->colo <= 0)
+      setmref(t->array, lj_mem_realloc(L, array,
+	      oldasize*sizeof(TValue), asize*sizeof(TValue)));
+  }
+  if (oldhmask > 0) {  /* Reinsert pairs from old hash part. */
+    global_State *g;
+    uint32_t i;
+    for (i = 0; i <= oldhmask; i++) {
+      Node *n = &oldnode[i];
+      if (!tvisnil(&n->val))
+	copyTV(L, lj_tab_set(L, t, &n->key), &n->val);
+    }
+    g = G(L);
+    lj_mem_freevec(g, oldnode, oldhmask+1, Node);
+  }
+}
+
+static uint32_t countint(cTValue *key, uint32_t *bins)
+{
+  lj_assertX(!tvisint(key), "bad integer key");
+  if (tvisnum(key)) {
+    lua_Number nk = numV(key);
+    int32_t k = lj_num2int(nk);
+    if ((uint32_t)k < LJ_MAX_ASIZE && nk == (lua_Number)k) {
+      bins[(k > 2 ? lj_fls((uint32_t)(k-1)) : 0)]++;
+      return 1;
+    }
+  }
+  return 0;
+}
+
+static uint32_t countarray(const GCtab *t, uint32_t *bins)
+{
+  uint32_t na, b, i;
+  if (t->asize == 0) return 0;
+  for (na = i = b = 0; b < LJ_MAX_ABITS; b++) {
+    uint32_t n, top = 2u << b;
+    TValue *array;
+    if (top >= t->asize) {
+      top = t->asize-1;
+      if (i > top)
+	break;
+    }
+    array = tvref(t->array);
+    for (n = 0; i <= top; i++)
+      if (!tvisnil(&array[i]))
+	n++;
+    bins[b] += n;
+    na += n;
+  }
+  return na;
+}
+
+static uint32_t counthash(const GCtab *t, uint32_t *bins, uint32_t *narray)
+{
+  uint32_t total, na, i, hmask = t->hmask;
+  Node *node = noderef(t->node);
+  for (total = na = 0, i = 0; i <= hmask; i++) {
+    Node *n = &node[i];
+    if (!tvisnil(&n->val)) {
+      na += countint(&n->key, bins);
+      total++;
+    }
+  }
+  *narray += na;
+  return total;
+}
+
+static uint32_t bestasize(uint32_t bins[], uint32_t *narray)
+{
+  uint32_t b, sum, na = 0, sz = 0, nn = *narray;
+  for (b = 0, sum = 0; 2*nn > (1u<<b) && sum != nn; b++)
+    if (bins[b] > 0 && 2*(sum += bins[b]) > (1u<<b)) {
+      sz = (2u<<b)+1;
+      na = sum;
+    }
+  *narray = sz;
+  return na;
+}
+
+static void rehashtab(lua_State *L, GCtab *t, cTValue *ek)
+{
+  uint32_t bins[LJ_MAX_ABITS];
+  uint32_t total, asize, na, i;
+  for (i = 0; i < LJ_MAX_ABITS; i++) bins[i] = 0;
+  asize = countarray(t, bins);
+  total = 1 + asize;
+  total += counthash(t, bins, &asize);
+  asize += countint(ek, bins);
+  na = bestasize(bins, &asize);
+  total -= na;
+  lj_tab_resize(L, t, asize, hsize2hbits(total));
+}
+
+#if LJ_HASFFI
+void lj_tab_rehash(lua_State *L, GCtab *t)
+{
+  rehashtab(L, t, niltv(L));
+}
+#endif
+
+void lj_tab_reasize(lua_State *L, GCtab *t, uint32_t nasize)
+{
+  lj_tab_resize(L, t, nasize+1, t->hmask > 0 ? lj_fls(t->hmask)+1 : 0);
+}
+
+/* -- Table getters ------------------------------------------------------- */
+
+cTValue * LJ_FASTCALL lj_tab_getinth(GCtab *t, int32_t key)
+{
+  TValue k;
+  Node *n;
+  k.n = (lua_Number)key;
+  n = hashnum(t, &k);
+  do {
+    if (tvisnum(&n->key) && n->key.n == k.n)
+      return &n->val;
+  } while ((n = nextnode(n)));
+  return NULL;
+}
+
+cTValue *lj_tab_getstr(GCtab *t, const GCstr *key)
+{
+  Node *n = hashstr(t, key);
+  do {
+    if (tvisstr(&n->key) && strV(&n->key) == key)
+      return &n->val;
+  } while ((n = nextnode(n)));
+  return NULL;
+}
+
+cTValue *lj_tab_get(lua_State *L, GCtab *t, cTValue *key)
+{
+  if (tvisstr(key)) {
+    cTValue *tv = lj_tab_getstr(t, strV(key));
+    if (tv)
+      return tv;
+  } else if (tvisint(key)) {
+    cTValue *tv = lj_tab_getint(t, intV(key));
+    if (tv)
+      return tv;
+  } else if (tvisnum(key)) {
+    lua_Number nk = numV(key);
+    int32_t k = lj_num2int(nk);
+    if (nk == (lua_Number)k) {
+      cTValue *tv = lj_tab_getint(t, k);
+      if (tv)
+	return tv;
+    } else {
+      goto genlookup;  /* Else use the generic lookup. */
+    }
+  } else if (!tvisnil(key)) {
+    Node *n;
+  genlookup:
+    n = hashkey(t, key);
+    do {
+      if (lj_obj_equal(&n->key, key))
+	return &n->val;
+    } while ((n = nextnode(n)));
+  }
+  return niltv(L);
+}
+
+/* -- Table setters ------------------------------------------------------- */
+
+/* Insert new key. Use Brent's variation to optimize the chain length. */
+TValue *lj_tab_newkey(lua_State *L, GCtab *t, cTValue *key)
+{
+  Node *n = hashkey(t, key);
+  if (!tvisnil(&n->val) || t->hmask == 0) {
+    Node *nodebase = noderef(t->node);
+    Node *collide, *freenode = getfreetop(t, nodebase);
+    lj_assertL(freenode >= nodebase && freenode <= nodebase+t->hmask+1,
+	       "bad freenode");
+    do {
+      if (freenode == nodebase) {  /* No free node found? */
+	rehashtab(L, t, key);  /* Rehash table. */
+	return lj_tab_set(L, t, key);  /* Retry key insertion. */
+      }
+    } while (!tvisnil(&(--freenode)->key));
+    setfreetop(t, nodebase, freenode);
+    lj_assertL(freenode != &G(L)->nilnode, "store to fallback hash");
+    collide = hashkey(t, &n->key);
+    if (collide != n) {  /* Colliding node not the main node? */
+      while (noderef(collide->next) != n)  /* Find predecessor. */
+	collide = nextnode(collide);
+      setmref(collide->next, freenode);  /* Relink chain. */
+      /* Copy colliding node into free node and free main node. */
+      freenode->val = n->val;
+      freenode->key = n->key;
+      freenode->next = n->next;
+      setmref(n->next, NULL);
+      setnilV(&n->val);
+      /* Rechain pseudo-resurrected string keys with colliding hashes. */
+      while (nextnode(freenode)) {
+	Node *nn = nextnode(freenode);
+	if (!tvisnil(&nn->val) && hashkey(t, &nn->key) == n) {
+	  freenode->next = nn->next;
+	  nn->next = n->next;
+	  setmref(n->next, nn);
+	  /*
+	  ** Rechaining a resurrected string key creates a new dilemma:
+	  ** Another string key may have originally been resurrected via
+	  ** _any_ of the previous nodes as a chain anchor. Including
+	  ** a node that had to be moved, which makes them unreachable.
+	  ** It's not feasible to check for all previous nodes, so rechain
+	  ** any string key that's currently in a non-main positions.
+	  */
+	  while ((nn = nextnode(freenode))) {
+	    if (!tvisnil(&nn->val)) {
+	      Node *mn = hashkey(t, &nn->key);
+	      if (mn != freenode && mn != nn) {
+		freenode->next = nn->next;
+		nn->next = mn->next;
+		setmref(mn->next, nn);
+	      } else {
+		freenode = nn;
+	      }
+	    } else {
+	      freenode = nn;
+	    }
+	  }
+	  break;
+	} else {
+	  freenode = nn;
+	}
+      }
+    } else {  /* Otherwise use free node. */
+      setmrefr(freenode->next, n->next);  /* Insert into chain. */
+      setmref(n->next, freenode);
+      n = freenode;
+    }
+  }
+  n->key.u64 = key->u64;
+  if (LJ_UNLIKELY(tvismzero(&n->key)))
+    n->key.u64 = 0;
+  lj_gc_anybarriert(L, t);
+  lj_assertL(tvisnil(&n->val), "new hash slot is not empty");
+  return &n->val;
+}
+
+TValue *lj_tab_setinth(lua_State *L, GCtab *t, int32_t key)
+{
+  TValue k;
+  Node *n;
+  k.n = (lua_Number)key;
+  n = hashnum(t, &k);
+  do {
+    if (tvisnum(&n->key) && n->key.n == k.n)
+      return &n->val;
+  } while ((n = nextnode(n)));
+  return lj_tab_newkey(L, t, &k);
+}
+
+TValue *lj_tab_setstr(lua_State *L, GCtab *t, const GCstr *key)
+{
+  TValue k;
+  Node *n = hashstr(t, key);
+  do {
+    if (tvisstr(&n->key) && strV(&n->key) == key)
+      return &n->val;
+  } while ((n = nextnode(n)));
+  setstrV(L, &k, key);
+  return lj_tab_newkey(L, t, &k);
+}
+
+TValue *lj_tab_set(lua_State *L, GCtab *t, cTValue *key)
+{
+  Node *n;
+  t->nomm = 0;  /* Invalidate negative metamethod cache. */
+  if (tvisstr(key)) {
+    return lj_tab_setstr(L, t, strV(key));
+  } else if (tvisint(key)) {
+    return lj_tab_setint(L, t, intV(key));
+  } else if (tvisnum(key)) {
+    lua_Number nk = numV(key);
+    int32_t k = lj_num2int(nk);
+    if (nk == (lua_Number)k)
+      return lj_tab_setint(L, t, k);
+    if (tvisnan(key))
+      lj_err_msg(L, LJ_ERR_NANIDX);
+    /* Else use the generic lookup. */
+  } else if (tvisnil(key)) {
+    lj_err_msg(L, LJ_ERR_NILIDX);
+  }
+  n = hashkey(t, key);
+  do {
+    if (lj_obj_equal(&n->key, key))
+      return &n->val;
+  } while ((n = nextnode(n)));
+  return lj_tab_newkey(L, t, key);
+}
+
+/* -- Table traversal ----------------------------------------------------- */
+
+/* Table traversal indexes:
+**
+** Array key index: [0 .. t->asize-1]
+** Hash key index:  [t->asize .. t->asize+t->hmask]
+** Invalid key:     ~0
+*/
+
+/* Get the successor traversal index of a key. */
+uint32_t LJ_FASTCALL lj_tab_keyindex(GCtab *t, cTValue *key)
+{
+  TValue tmp;
+  if (tvisint(key)) {
+    int32_t k = intV(key);
+    if ((uint32_t)k < t->asize)
+      return (uint32_t)k + 1;
+    setnumV(&tmp, (lua_Number)k);
+    key = &tmp;
+  } else if (tvisnum(key)) {
+    lua_Number nk = numV(key);
+    int32_t k = lj_num2int(nk);
+    if ((uint32_t)k < t->asize && nk == (lua_Number)k)
+      return (uint32_t)k + 1;
+  }
+  if (!tvisnil(key)) {
+    Node *n = hashkey(t, key);
+    do {
+      if (lj_obj_equal(&n->key, key))
+	return t->asize + (uint32_t)((n+1) - noderef(t->node));
+    } while ((n = nextnode(n)));
+    if (key->u32.hi == LJ_KEYINDEX)  /* Despecialized ITERN while running. */
+      return key->u32.lo;
+    return ~0u;  /* Invalid key to next. */
+  }
+  return 0;  /* A nil key starts the traversal. */
+}
+
+/* Get the next key/value pair of a table traversal. */
+int lj_tab_next(GCtab *t, cTValue *key, TValue *o)
+{
+  uint32_t idx = lj_tab_keyindex(t, key);  /* Find successor index of key. */
+  /* First traverse the array part. */
+  for (; idx < t->asize; idx++) {
+    cTValue *a = arrayslot(t, idx);
+    if (LJ_LIKELY(!tvisnil(a))) {
+      setintV(o, idx);
+      o[1] = *a;
+      return 1;
+    }
+  }
+  idx -= t->asize;
+  /* Then traverse the hash part. */
+  for (; idx <= t->hmask; idx++) {
+    Node *n = &noderef(t->node)[idx];
+    if (!tvisnil(&n->val)) {
+      o[0] = n->key;
+      o[1] = n->val;
+      return 1;
+    }
+  }
+  return (int32_t)idx < 0 ? -1 : 0;  /* Invalid key or end of traversal. */
+}
+
+/* -- Table length calculation -------------------------------------------- */
+
+/* Compute table length. Slow path with mixed array/hash lookups. */
+LJ_NOINLINE static MSize tab_len_slow(GCtab *t, size_t hi)
+{
+  cTValue *tv;
+  size_t lo = hi;
+  hi++;
+  /* Widening search for an upper bound. */
+  while ((tv = lj_tab_getint(t, (int32_t)hi)) && !tvisnil(tv)) {
+    lo = hi;
+    hi += hi;
+    if (hi > (size_t)(INT_MAX-2)) {  /* Punt and do a linear search. */
+      lo = 1;
+      while ((tv = lj_tab_getint(t, (int32_t)lo)) && !tvisnil(tv)) lo++;
+      return (MSize)(lo - 1);
+    }
+  }
+  /* Binary search to find a non-nil to nil transition. */
+  while (hi - lo > 1) {
+    size_t mid = (lo+hi) >> 1;
+    cTValue *tvb = lj_tab_getint(t, (int32_t)mid);
+    if (tvb && !tvisnil(tvb)) lo = mid; else hi = mid;
+  }
+  return (MSize)lo;
+}
+
+/* Compute table length. Fast path. */
+MSize LJ_FASTCALL lj_tab_len(GCtab *t)
+{
+  size_t hi = (size_t)t->asize;
+  if (hi) hi--;
+  /* In a growing array the last array element is very likely nil. */
+  if (hi > 0 && LJ_LIKELY(tvisnil(arrayslot(t, hi)))) {
+    /* Binary search to find a non-nil to nil transition in the array. */
+    size_t lo = 0;
+    while (hi - lo > 1) {
+      size_t mid = (lo+hi) >> 1;
+      if (tvisnil(arrayslot(t, mid))) hi = mid; else lo = mid;
+    }
+    return (MSize)lo;
+  }
+  /* Without a hash part, there's an implicit nil after the last element. */
+  return t->hmask ? tab_len_slow(t, hi) : (MSize)hi;
+}
+
+#if LJ_HASJIT
+/* Verify hinted table length or compute it. */
+MSize LJ_FASTCALL lj_tab_len_hint(GCtab *t, size_t hint)
+{
+  size_t asize = (size_t)t->asize;
+  cTValue *tv = arrayslot(t, hint);
+  if (LJ_LIKELY(hint+1 < asize)) {
+    if (LJ_LIKELY(!tvisnil(tv) && tvisnil(tv+1))) return (MSize)hint;
+  } else if (hint+1 <= asize && LJ_LIKELY(t->hmask == 0) && !tvisnil(tv)) {
+    return (MSize)hint;
+  }
+  return lj_tab_len(t);
+}
+#endif
+