From 22ef84b6c8d980eb869f414610f8ff5f25568ca7 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Sat, 13 Mar 2010 12:55:42 -0300
Subject: [PATCH] '_ENV' name permanently stored in global state for easier
 access

---
 ldebug.c  | 4 ++--
 llex.h    | 3 +--
 lparser.c | 9 +++------
 lstate.c  | 4 +++-
 lstate.h  | 3 ++-
 5 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/ldebug.c b/ldebug.c
index 898efe53..08560acd 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 2.65 2010/03/05 14:01:29 roberto Exp roberto $
+** $Id: ldebug.c,v 2.66 2010/03/12 19:14:06 roberto Exp roberto $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -304,7 +304,7 @@ static const char *getobjname (lua_State *L, CallInfo *ci, int reg,
                                 ? luaF_getlocalname(p, t + 1, pc)
                                 : getstr(p->upvalues[t].name);
           kname(p, k, a, what, name);
-          what = (tabname && strcmp(tabname, "_ENV") == 0) ? "global" : "field";
+          what = (tabname == getstr(G(L)->envn)) ? "global" : "field";
         }
         break;
       }
diff --git a/llex.h b/llex.h
index 7eb2f274..276802e0 100644
--- a/llex.h
+++ b/llex.h
@@ -1,5 +1,5 @@
 /*
-** $Id: llex.h,v 1.62 2009/10/11 20:02:19 roberto Exp roberto $
+** $Id: llex.h,v 1.63 2010/03/08 16:55:52 roberto Exp roberto $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
@@ -60,7 +60,6 @@ typedef struct LexState {
   Mbuffer *buff;  /* buffer for tokens */
   struct Varlist *varl;  /* list of all active local variables */
   TString *source;  /* current source name */
-  TString *envn;  /* name of environment variable */
   char decpoint;  /* locale decimal point */
 } LexState;
 
diff --git a/lparser.c b/lparser.c
index 6ce0bdbf..12978acb 100644
--- a/lparser.c
+++ b/lparser.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 2.78 2010/03/08 16:55:52 roberto Exp roberto $
+** $Id: lparser.c,v 2.79 2010/03/12 19:14:06 roberto Exp roberto $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -288,7 +288,7 @@ static void singlevar (LexState *ls, expdesc *var) {
   FuncState *fs = ls->fs;
   if (singlevaraux(fs, varname, var, 1) == VVOID) {  /* global name? */
     expdesc key;
-    singlevaraux(fs, ls->envn, var, 1);  /* get _ENV variable */
+    singlevaraux(fs, G(ls->L)->envn, var, 1);  /* get _ENV variable */
     lua_assert(var->k == VLOCAL || var->k == VUPVAL);
     codestring(ls, &key, varname);  /* key is variable name */
     luaK_indexed(fs, var, &key);  /* env[varname] */
@@ -433,11 +433,8 @@ static void open_mainfunc (lua_State *L, LexState *ls, FuncState *fs) {
   expdesc v;
   open_func(ls, fs);
   fs->f->is_vararg = 1;  /* main function is always vararg */
-  ls->envn = luaS_new(L, "_ENV");  /* create '_ENV' string */
-  setsvalue2s(L, L->top++, ls->envn);  /* anchor it */
   init_exp(&v, VLOCAL, 0);
-  newupvalue(fs, ls->envn, &v);  /* create '_ENV' upvalue */
-  L->top--;  /* now string is anchored as an upvalue name */
+  newupvalue(fs, G(L)->envn, &v);  /* create '_ENV' upvalue */
 }
 
 
diff --git a/lstate.c b/lstate.c
index 2fc282e7..9685f2a5 100644
--- a/lstate.c
+++ b/lstate.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.c,v 2.67 2009/12/17 12:26:09 roberto Exp roberto $
+** $Id: lstate.c,v 2.68 2009/12/22 15:32:50 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -161,6 +161,8 @@ static void f_luaopen (lua_State *L, void *ud) {
   luaS_resize(L, MINSTRTABSIZE);  /* initial size of string table */
   luaT_init(L);
   luaX_init(L);
+  g->envn = luaS_new(L, "_ENV");
+  luaS_fix(g->envn);  /* never collect this name */
   luaS_fix(luaS_newliteral(L, MEMERRMSG));
   g->GCthreshold = 4*g->totalbytes;
 }
diff --git a/lstate.h b/lstate.h
index a6ea5546..eb0068fe 100644
--- a/lstate.h
+++ b/lstate.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.h,v 2.52 2009/12/22 15:32:50 roberto Exp roberto $
+** $Id: lstate.h,v 2.53 2010/02/09 11:55:37 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -144,6 +144,7 @@ typedef struct global_State {
   const lua_Number *version;  /* pointer to version number */
   struct Table *mt[NUM_TAGS];  /* metatables for basic types */
   TString *tmname[TM_N];  /* array with tag-method names */
+  TString *envn;  /* environment variable name */
 } global_State;