commit 65d2294454ab68d164154c7ce05caa50bd97d143
author Roberto Ierusalimschy <roberto@inf.puc-rio.br> Thu Nov 26 18:23:40 2020 -0300
committer Roberto Ierusalimschy <roberto@inf.puc-rio.br> Thu Nov 26 18:23:40 2020 -0300
tree 6cd1a6d00eaf7156d1537d165de26abf82787782
parent 131e3fd814a6e818b412407a222186aab08f3525

Changed access to global table in the registry

The global table is always in the array part of the registry; we can
use this fact to make its access slightly more efficient.

lapi.c

diff --git a/lapi.c b/lapi.c
index c824da2..9fffcc1 100644
--- a/lapi.c
+++ b/lapi.c
@@ -629,11 +629,21 @@
 }
 
 
+/*
+** Get the global table in the registry. Since all predefined
+** indices in the registry were inserted right when the registry
+** was created and never removed, they must always be in the array
+** part of the registry.
+*/
+#define getGtable(L)  \
+	(&hvalue(&G(L)->l_registry)->array[LUA_RIDX_GLOBALS - 1])
+
+
 LUA_API int lua_getglobal (lua_State *L, const char *name) {
-  Table *reg;
+  const TValue *G;
   lua_lock(L);
-  reg = hvalue(&G(L)->l_registry);
-  return auxgetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
+  G = getGtable(L);
+  return auxgetstr(L, G, name);
 }
 
 
@@ -811,10 +821,10 @@
 
 
 LUA_API void lua_setglobal (lua_State *L, const char *name) {
-  Table *reg;
+  const TValue *G;
   lua_lock(L);  /* unlock done in 'auxsetstr' */
-  reg = hvalue(&G(L)->l_registry);
-  auxsetstr(L, luaH_getint(reg, LUA_RIDX_GLOBALS), name);
+  G = getGtable(L);
+  auxsetstr(L, G, name);
 }
 
 
@@ -1063,8 +1073,7 @@
     LClosure *f = clLvalue(s2v(L->top - 1));  /* get newly created function */
     if (f->nupvalues >= 1) {  /* does it have an upvalue? */
       /* get global table from registry */
-      Table *reg = hvalue(&G(L)->l_registry);
-      const TValue *gt = luaH_getint(reg, LUA_RIDX_GLOBALS);
+      const TValue *gt = getGtable(L);
       /* set global table as 1st upvalue of 'f' (may be LUA_ENV) */
       setobj(L, f->upvals[0]->v, gt);
       luaC_barrier(L, f->upvals[0], gt);

lstate.c

diff --git a/lstate.c b/lstate.c
index 1c7b879..1596b51 100644
--- a/lstate.c
+++ b/lstate.c
@@ -213,17 +213,14 @@
 ** Create registry table and its predefined values
 */
 static void init_registry (lua_State *L, global_State *g) {
-  TValue temp;
   /* create registry */
   Table *registry = luaH_new(L);
   sethvalue(L, &g->l_registry, registry);
   luaH_resize(L, registry, LUA_RIDX_LAST, 0);
   /* registry[LUA_RIDX_MAINTHREAD] = L */
-  setthvalue(L, &temp, L);  /* temp = L */
-  luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &temp);
-  /* registry[LUA_RIDX_GLOBALS] = table of globals */
-  sethvalue(L, &temp, luaH_new(L));  /* temp = new table (global table) */
-  luaH_setint(L, registry, LUA_RIDX_GLOBALS, &temp);
+  setthvalue(L, &registry->array[LUA_RIDX_MAINTHREAD - 1], L);
+  /* registry[LUA_RIDX_GLOBALS] = new table (table of globals) */
+  sethvalue(L, &registry->array[LUA_RIDX_GLOBALS - 1], luaH_new(L));
 }