commit 9eff921f8fe689794308cdb3fa7bb214604f75d3
parent 8e6b7ef9ab226b9184d300ad1b14c3812a6e86d8
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 19 Aug 2013 11:18:18 -0300
"barrier" for link prototype->cache changed to be consistent with
GC behavior (link is cleared to preserve invariant)
Diffstat:
| M | lgc.c | | | 24 | +----------------------- |
| M | lgc.h | | | 5 | +---- |
| M | lvm.c | | | 12 | ++++++------ |
3 files changed, 8 insertions(+), 33 deletions(-)
diff --git a/lgc.c b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 2.145 2013/08/13 17:36:44 roberto Exp roberto $
+** $Id: lgc.c,v 2.146 2013/08/16 18:55:49 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -172,28 +172,6 @@ void luaC_barrierback_ (lua_State *L, GCObject *o) {
/*
-** barrier for prototypes. When creating first closure (cache is
-** NULL), use a forward barrier; this may be the only closure of the
-** prototype (if it is a "regular" function, with a single instance)
-** and the prototype may be big, so it is better to avoid traversing
-** it again. Otherwise, use a backward barrier, to avoid marking all
-** possible instances.
-*/
-LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c) {
- global_State *g = G(L);
- lua_assert(isblack(obj2gco(p)));
- if (p->cache == NULL) { /* first time? */
- luaC_objbarrier(L, p, c);
- }
- else { /* use a backward barrier */
- black2gray(obj2gco(p)); /* make prototype gray (again) */
- p->gclist = g->grayagain;
- g->grayagain = obj2gco(p);
- }
-}
-
-
-/*
** check color (and invariants) for an upvalue that is being closed,
** i.e., moved into the 'allgc' list
*/
diff --git a/lgc.h b/lgc.h
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.h,v 2.60 2013/08/13 17:36:44 roberto Exp roberto $
+** $Id: lgc.h,v 2.61 2013/08/16 18:55:49 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -128,9 +128,6 @@
{ if (nolocal(obj2gco(o)), isblack(obj2gco(p)) && iswhite(obj2gco(o))) \
luaC_barrierback_(L,p); }
-#define luaC_barrierproto(L,p,c) \
- { if (nolocal(obj2gco(c)), isblack(obj2gco(p))) luaC_barrierproto_(L,p,c); }
-
LUAI_FUNC void luaC_freeallobjects (lua_State *L);
LUAI_FUNC void luaC_step (lua_State *L);
LUAI_FUNC void luaC_forcestep (lua_State *L);
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.176 2013/07/10 17:15:12 roberto Exp roberto $
+** $Id: lvm.c,v 2.177 2013/08/16 18:55:49 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -399,9 +399,9 @@ static Closure *getcached (Proto *p, UpVal **encup, StkId base) {
/*
** create a new Lua closure, push it in the stack, and initialize
-** its upvalues. Note that the call to 'luaC_barrierproto' must come
-** before the assignment to 'p->cache', as the function needs the
-** original value of that field.
+** its upvalues. Note that the closure is not cached if prototype is
+** already black (which means that 'cache' was already cleared by the
+** GC).
*/
static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
StkId ra) {
@@ -418,8 +418,8 @@ static void pushclosure (lua_State *L, Proto *p, UpVal **encup, StkId base,
ncl->l.upvals[i] = encup[uv[i].idx];
/* new closure is white and local, so we do not need a barrier here */
}
- luaC_barrierproto(L, p, ncl);
- p->cache = ncl; /* save it on cache for reuse */
+ if (!isblack(obj2gco(p))) /* cache will not break GC invariant? */
+ p->cache = ncl; /* save it on cache for reuse */
}
