From 0e54d2be365ec77cb455e0d0f3c5c6f9efa6e04c Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 15 Sep 2004 17:38:15 -0300
Subject: [PATCH] bug: barrier was wrong for generational phase

---
 lgc.c | 18 +++++++++++-------
 lgc.h |  6 +++++-
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/lgc.c b/lgc.c
index 6beaa55b..1273d58d 100644
--- a/lgc.c
+++ b/lgc.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 2.10 2004/08/30 13:44:44 roberto Exp roberto $
+** $Id: lgc.c,v 2.11 2004/09/08 14:23:09 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -499,7 +499,7 @@ void luaC_freeall (lua_State *L) {
 /* mark root set */
 static void markroot (lua_State *L) {
   global_State *g = G(L);
-  lua_assert(g->gray == NULL);
+  g->gray = NULL;
   g->grayagain = NULL;
   g->weak = NULL;
   markobject(g, g->mainthread);
@@ -513,6 +513,7 @@ static void markroot (lua_State *L) {
 static void remarkupvals (global_State *g) {
   GCObject *o;
   for (o = obj2gco(g->mainthread); o; o = o->gch.next) {
+    lua_assert(!isblack(o));
     if (iswhite(o)) {
       GCObject *curr;
       for (curr = gco2th(o)->openupval; curr != NULL; curr = curr->gch.next) {
@@ -529,7 +530,8 @@ static void remarkupvals (global_State *g) {
 static void atomic (lua_State *L) {
   global_State *g = G(L);
   int aux;
-  lua_assert(g->gray == NULL);
+  /* remark objects cautch by write barrier */
+  propagateall(g);
   /* remark occasional upvalues of (maybe) dead threads */
   remarkupvals(g);
   /* remark weak tables */
@@ -669,10 +671,12 @@ void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v) {
   global_State *g = G(L);
   lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
   lua_assert(g->gcgenerational || g->gcstate != GCSfinalize);
-  if (g->gcstate != GCSpropagate)  /* sweeping phases? */
-    black2gray(o);  /* just mark as gray to avoid other barriers */
-  else  /* breaking invariant! */
-    reallymarkobject(g, v);  /* restore it */
+  lua_assert(ttype(&o->gch) != LUA_TTABLE);
+  /* must keep invariant? */
+  if (g->gcstate == GCSpropagate || g->gcgenerational)
+    reallymarkobject(g, v);  /* restore invariant */
+  else  /* don't mind */
+    makewhite(g, o);  /* mark as white just to avoid other barriers */
 }
 
 
diff --git a/lgc.h b/lgc.h
index b4097b05..f8a18782 100644
--- a/lgc.h
+++ b/lgc.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.h,v 2.7 2004/08/24 20:12:06 roberto Exp roberto $
+** $Id: lgc.h,v 2.8 2004/08/30 13:44:44 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -86,6 +86,10 @@
 	{ if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
 		luaC_barrierf(L,obj2gco(p),obj2gco(o)); }
 
+#define luaC_objbarriert(L,p,o)  \
+	{ if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
+		luaC_barrierback(L,obj2gco(p),obj2gco(o)); }
+
 size_t luaC_separateudata (lua_State *L, int all);
 void luaC_callGCTM (lua_State *L);
 void luaC_freeall (lua_State *L);