From 07c7fdb9df82c7fc4ae501e21262f781df4ae5e5 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 29 Jul 2014 13:22:24 -0300
Subject: [PATCH] simpler definition for 'setobj' (trust the compiler for the
 assignment)

---
 lgc.c     |  4 ++--
 lobject.h | 12 +++++++++---
 ltable.c  |  9 +++++----
 ltable.h  |  9 +++++++--
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/lgc.c b/lgc.c
index 0fe426e8..a4059d34 100644
--- a/lgc.c
+++ b/lgc.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 2.190 2014/07/19 15:09:37 roberto Exp roberto $
+** $Id: lgc.c,v 2.191 2014/07/19 15:14:46 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -112,7 +112,7 @@ static void reallymarkobject (global_State *g, GCObject *o);
 static void removeentry (Node *n) {
   lua_assert(ttisnil(gval(n)));
   if (valiswhite(gkey(n)))
-    setdeadvalue(gkey(n));  /* unused and unmarked key; remove it */
+    setdeadvalue(wgkey(n));  /* unused and unmarked key; remove it */
 }
 
 
diff --git a/lobject.h b/lobject.h
index a5827f84..93356dd2 100644
--- a/lobject.h
+++ b/lobject.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.h,v 2.98 2014/07/18 13:36:14 roberto Exp roberto $
+** $Id: lobject.h,v 2.99 2014/07/18 14:46:47 roberto Exp roberto $
 ** Type definitions for Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -241,8 +241,7 @@ typedef struct lua_TValue TValue;
 
 
 #define setobj(L,obj1,obj2) \
-	{ const TValue *io2=(obj2); TValue *io1=(obj1); \
-	  io1->value_ = io2->value_; io1->tt_ = io2->tt_; \
+	{ TValue *io1=(obj1); *io1 = *(obj2); \
 	  (void)L; checkliveness(G(L),io1); }
 
 
@@ -471,6 +470,13 @@ typedef union TKey {
 } TKey;
 
 
+/* copy a value into a key without messing up field 'next' */
+#define setkey(L,key,obj) \
+	{ TKey *k_=(key); const TValue *io_=(obj); \
+	  k_->nk.value_ = io_->value_; k_->nk.tt_ = io_->tt_; \
+	  (void)L; checkliveness(G(L),io_); }
+
+
 typedef struct Node {
   TValue i_val;
   TKey i_key;
diff --git a/ltable.c b/ltable.c
index a234bebb..543c34df 100644
--- a/ltable.c
+++ b/ltable.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltable.c,v 2.91 2014/06/26 16:17:35 roberto Exp roberto $
+** $Id: ltable.c,v 2.92 2014/07/18 13:36:14 roberto Exp roberto $
 ** Lua tables (hash)
 ** See Copyright Notice in lua.h
 */
@@ -309,7 +309,7 @@ static void setnodevector (lua_State *L, Table *t, int size) {
     for (i=0; i<size; i++) {
       Node *n = gnode(t, i);
       gnext(n) = 0;
-      setnilvalue(gkey(n));
+      setnilvalue(wgkey(n));
       setnilvalue(gval(n));
     }
   }
@@ -466,7 +466,7 @@ TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
       mp = f;
     }
   }
-  setobj2t(L, gkey(mp), key);
+  setkey(L, &mp->i_key, key);
   luaC_barrierback(L, t, key);
   lua_assert(ttisnil(gval(mp)));
   return gval(mp);
@@ -503,7 +503,8 @@ const TValue *luaH_getstr (Table *t, TString *key) {
   Node *n = hashstr(t, key);
   lua_assert(key->tt == LUA_TSHRSTR);
   for (;;) {  /* check whether `key' is somewhere in the chain */
-    if (ttisshrstring(gkey(n)) && eqshrstr(tsvalue(gkey(n)), key))
+    const TValue *k = gkey(n);
+    if (ttisshrstring(k) && eqshrstr(tsvalue(k), key))
       return gval(n);  /* that's it */
     else {
       int nx = gnext(n);
diff --git a/ltable.h b/ltable.h
index f377c009..a4570d9d 100644
--- a/ltable.h
+++ b/ltable.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ltable.h,v 2.17 2013/04/26 15:39:25 roberto Exp roberto $
+** $Id: ltable.h,v 2.18 2013/08/30 16:01:37 roberto Exp roberto $
 ** Lua tables (hash)
 ** See Copyright Notice in lua.h
 */
@@ -11,10 +11,15 @@
 
 
 #define gnode(t,i)	(&(t)->node[i])
-#define gkey(n)		(&(n)->i_key.tvk)
 #define gval(n)		(&(n)->i_val)
 #define gnext(n)	((n)->i_key.nk.next)
 
+
+/* 'const' to avoid wrong writings that can mess up field 'next' */ 
+#define gkey(n)		cast(const TValue*, (&(n)->i_key.tvk))
+
+#define wgkey(n)		(&(n)->i_key.nk)
+
 #define invalidateTMcache(t)	((t)->flags = 0)