1 files changed, 28 insertions, 0 deletions

diff --git a/src/lj_udata.c b/src/lj_udata.c
index 7dada848..ee4a145d 100644
--- a/src/lj_udata.c
+++ b/src/lj_udata.c
@@ -8,6 +8,7 @@
 
 #include "lj_obj.h"
 #include "lj_gc.h"
+#include "lj_err.h"
 #include "lj_udata.h"
 
 GCudata *lj_udata_new(lua_State *L, MSize sz, GCtab *env)
@@ -32,3 +33,30 @@ void LJ_FASTCALL lj_udata_free(global_State *g, GCudata *ud)
   lj_mem_free(g, ud, sizeudata(ud));
 }
 
+#if LJ_64
+void *lj_lightud_intern(lua_State *L, void *p)
+{
+  global_State *g = G(L);
+  uint64_t u = (uint64_t)p;
+  uint32_t up = lightudup(u);
+  uint32_t *segmap = mref(g->gc.lightudseg, uint32_t);
+  MSize segnum = g->gc.lightudnum;
+  if (segmap) {
+    MSize seg;
+    for (seg = 0; seg <= segnum; seg++)
+      if (segmap[seg] == up)  /* Fast path. */
+        return (void *)(((uint64_t)seg << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
+    segnum++;
+    /* Leave last segment unused to avoid clash with ITERN key. */
+    if (segnum >= (1 << LJ_LIGHTUD_BITS_SEG)-1) lj_err_msg(L, LJ_ERR_BADLU);
+  }
+  if (!((segnum-1) & segnum) && segnum != 1) {
+    lj_mem_reallocvec(L, segmap, segnum, segnum ? 2*segnum : 2u, uint32_t);
+    setmref(g->gc.lightudseg, segmap);
+  }
+  g->gc.lightudnum = segnum;
+  segmap[segnum] = up;
+  return (void *)(((uint64_t)segnum << LJ_LIGHTUD_BITS_LO) | lightudlo(u));
+}
+#endif
+