more and better tools (assertions & inspectors) to check incremental GC

author: Roberto Ierusalimschy <roberto@inf.puc-rio.br> 2004-02-16 16:09:52 -0300
committer: Roberto Ierusalimschy <roberto@inf.puc-rio.br> 2004-02-16 16:09:52 -0300
commit: 2aaf7394ad17180565423ce360d5faffb60f4e4f (patch)
tree: 32caa2d7b0079b4bc9b0ac392d216c5094a6433d /lgc.c
parent: b3ce4505296253e6da1fa780c23e7ed012efc88e (diff)
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1 files changed, 39 insertions, 22 deletions
diff --git a/lgc.c b/lgc.c
index fe6461c0..ae5cd686 100644
--- a/lgc.c
+++ b/lgc.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 2.1 2003/12/10 12:13:36 roberto Exp roberto $
+** $Id: lgc.c,v 2.2 2003/12/12 18:29:34 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -60,6 +60,7 @@
 /*
 ** computes the size of a collectible object
 */
@@ -152,7 +153,7 @@ static void marktmu (global_State *g) {
 /* move `dead' udata that need finalization to list `tmudata' */
-size_t luaC_separateudata (lua_State *L) {
+size_t luaC_separateudata (lua_State *L, int all) {
  size_t deadmem = 0;
  GCObject **p = &G(L)->firstudata;
  GCObject *curr;
@@ -160,7 +161,7 @@ size_t luaC_separateudata (lua_State *L) {
  GCObject **lastcollected = &collected;
  while ((curr = *p) != NULL) {
    lua_assert(curr->gch.tt == LUA_TUSERDATA);
-    if (!iswhite(curr) || isfinalized(gco2u(curr)))
+    if (!(iswhite(curr) || all) || isfinalized(gco2u(curr)))
      p = &curr->gch.next;  /* don't bother with them */
    else if (fasttm(L, gco2u(curr)->metatable, TM_GC) == NULL) {
      markfinalized(gco2u(curr));  /* don't need finalization */
@@ -182,7 +183,7 @@ size_t luaC_separateudata (lua_State *L) {
 }
-static void traversetable (global_State *g, Table *h) {
+static int traversetable (global_State *g, Table *h) {
  int i;
  int weakkey = 0;
  int weakvalue = 0;
@@ -202,7 +203,7 @@ static void traversetable (global_State *g, Table *h) {
      g->weak = obj2gco(h);  /* ... so put in the appropriate list */
    }
  }
-  if (weakkey && weakvalue) return;
+  if (weakkey && weakvalue) return 1;
  if (!weakvalue) {
    i = h->sizearray;
    while (i--)
@@ -217,6 +218,7 @@ static void traversetable (global_State *g, Table *h) {
      condmarkobject(g, gval(n), !weakvalue);
    }
  }
+  return weakkey || weakvalue;
 }
@@ -227,10 +229,8 @@ static void traversetable (global_State *g, Table *h) {
 static void traverseproto (global_State *g, Proto *f) {
  int i;
  if (f->source) stringmark(f->source);
-  for (i=0; i<f->sizek; i++) {  /* mark literal strings */
+  for (i=0; i<f->sizek; i++)  /* mark literals */
-    if (ttisstring(f->k+i))
+    markvalue(g, &f->k[i]);
-      stringmark(rawtsvalue(f->k+i));
-  }
  for (i=0; i<f->sizeupvalues; i++) {  /* mark upvalue names */
    if (f->upvalues[i])
      stringmark(f->upvalues[i]);
@@ -258,9 +258,8 @@ static void traverseclosure (global_State *g, Closure *cl) {
    lua_assert(cl->l.nupvalues == cl->l.p->nups);
    markobject(g, hvalue(&cl->l.g));
    markobject(g, cl->l.p);
-    for (i=0; i<cl->l.nupvalues; i++) {  /* mark its upvalues */
+    for (i=0; i<cl->l.nupvalues; i++)  /* mark its upvalues */
      markobject(g, cl->l.upvals[i]);
-    }
  }
 }
@@ -307,7 +306,8 @@ static l_mem propagatemarks (global_State *g, l_mem lim) {
      case LUA_TTABLE: {
        Table *h = gco2h(o);
        g->gray = h->gclist;
-        traversetable(g, h);
+        if (traversetable(g, h))  /* table is weak? */
+          black2gray(o);  /* keep it gray */
        break;
      }
      case LUA_TFUNCTION: {
@@ -339,7 +339,8 @@ static l_mem propagatemarks (global_State *g, l_mem lim) {
          g->grayagain = o;
          black2gray(o);
        }
-        markvalue(g, &uv->value);
+        else
+          markvalue(g, &uv->value);
        break;
      }
      default: lua_assert(0);
@@ -428,6 +429,13 @@ static void freeobj (lua_State *L, GCObject *o) {
 }
+static void sweepupvalues (global_State *g, lua_State *L1) {
+  GCObject *curr;
+  for (curr = L1->openupval; curr != NULL; curr = curr->gch.next)
+    makewhite(g, curr);
+}
 static GCObject **sweeplist (lua_State *L, GCObject **p, int all,
                             l_mem *plim) {
  GCObject *curr;
@@ -439,10 +447,14 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, int all,
    lim -= objsize(curr);
    if (!all && (!(mark & dead) || testbit(mark, FIXEDBIT))) {
      makewhite(g, curr);
+      if (curr->gch.tt == LUA_TTHREAD)
+        sweepupvalues(g, gco2th(curr));
      p = &curr->gch.next;
    }
    else {
      *p = curr->gch.next;
+      if (curr == g->rootgc)  /* is the first element of the list? */
+        g->rootgc = curr->gch.next;  /* adjust first */
      freeobj(L, curr);
    }
    if (lim <= 0) break;
@@ -537,7 +549,8 @@ void luaC_sweepall (lua_State *L) {
 /* mark root set */
 static void markroot (lua_State *L) {
  global_State *g = G(L);
-  lua_assert(g->gray == NULL && g->grayagain == NULL);
+  lua_assert(g->gray == NULL);
+  g->grayagain = NULL;
  g->weak = NULL;
  makewhite(g, obj2gco(g->mainthread));
  markobject(g, g->mainthread);
@@ -550,28 +563,30 @@ static void markroot (lua_State *L) {
 static void atomic (lua_State *L) {
  global_State *g = G(L);
  lua_assert(g->gray == NULL);
+  /* remark weak tables */
+  g->gray = g->weak;
+  g->weak = NULL;
+  propagatemarks(g, MAXLMEM);
+  /* remark gray again */
  g->gray = g->grayagain;
  g->grayagain = NULL;
  propagatemarks(g, MAXLMEM);
-  luaC_separateudata(L);  /* separate userdata to be preserved */
+  luaC_separateudata(L, 0);  /* separate userdata to be preserved */
  marktmu(g);  /* mark `preserved' userdata */
  propagatemarks(g, MAXLMEM);  /* remark, to propagate `preserveness' */
  cleartable(g->weak);  /* remove collected objects from weak tables */
  /* flip current white */
  g->currentwhite = otherwhite(g);
-  /* first element of root list will be used as temporary head for sweep
+  g->sweepgc = &g->rootgc;
-     phase, so it won't be swept */
-  makewhite(g, g->rootgc);
-  g->sweepgc = &g->rootgc->gch.next;
  g->sweepstrgc = 0;
  g->gcstate = GCSsweepstring;
-  g->grayagain = NULL;
 }
 void luaC_step (lua_State *L) {
  global_State *g = G(L);
  l_mem lim = (g->nblocks - (g->GCthreshold - GCSTEPSIZE)) * 2;
+luaC_checkall(L);
  switch (g->gcstate) {
    case GCSpropagate: {
      if (g->gray)
@@ -593,8 +608,9 @@ void luaC_step (lua_State *L) {
    case GCSsweep: {
      g->sweepgc = sweeplist(L, g->sweepgc, 0, &lim);
      if (*g->sweepgc == NULL) {  /* nothing more to sweep? */
-        g->gcstate = GCSfinalize;  /* end sweep phase */
        checkSizes(L);
+        sweepupvalues(g, g->mainthread);
+        g->gcstate = GCSfinalize;  /* end sweep phase */
      }
      break;
    }
@@ -610,13 +626,14 @@ void luaC_step (lua_State *L) {
    default: lua_assert(0);
  }
  g->GCthreshold = g->nblocks + GCSTEPSIZE - lim/2;
+luaC_checkall(L);
 }
 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));
-  if (g->gcstate >= GCSsweepstring)  /* sweeping phases? */
+  if (g->gcstate != GCSpropagate)  /* sweeping phases? */
    black2gray(o);  /* just mark as gray to avoid other barriers */
  else  /* breaking invariant! */
    reallymarkobject(g, v);  /* restore it */
author	Roberto Ierusalimschy <roberto@inf.puc-rio.br>	2004-02-16 16:09:52 -0300
committer	Roberto Ierusalimschy <roberto@inf.puc-rio.br>	2004-02-16 16:09:52 -0300
commit	2aaf7394ad17180565423ce360d5faffb60f4e4f (patch)
tree	32caa2d7b0079b4bc9b0ac392d216c5094a6433d /lgc.c
parent	b3ce4505296253e6da1fa780c23e7ed012efc88e (diff)
download	lua-2aaf7394ad17180565423ce360d5faffb60f4e4f.tar.gz lua-2aaf7394ad17180565423ce360d5faffb60f4e4f.tar.bz2 lua-2aaf7394ad17180565423ce360d5faffb60f4e4f.zip