1 files changed, 103 insertions, 56 deletions

diff --git a/apps/plugins/lua/lgc.h b/apps/plugins/lua/lgc.h
index 5123ccb479..84bb1cdf99 100644
--- a/apps/plugins/lua/lgc.h
+++ b/apps/plugins/lua/lgc.h
@@ -1,5 +1,5 @@
 /*
-** $Id$
+** $Id: lgc.h,v 2.58.1.1 2013/04/12 18:48:47 roberto Exp $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -9,65 +9,107 @@
 
 
 #include "lobject.h"
+#include "lstate.h"
+
+/*
+** Collectable objects may have one of three colors: white, which
+** means the object is not marked; gray, which means the
+** object is marked, but its references may be not marked; and
+** black, which means that the object and all its references are marked.
+** The main invariant of the garbage collector, while marking objects,
+** is that a black object can never point to a white one. Moreover,
+** any gray object must be in a "gray list" (gray, grayagain, weak,
+** allweak, ephemeron) so that it can be visited again before finishing
+** the collection cycle. These lists have no meaning when the invariant
+** is not being enforced (e.g., sweep phase).
+*/
+
+
+
+/* how much to allocate before next GC step */
+#if !defined(GCSTEPSIZE)
+/* ~100 small strings */
+#define GCSTEPSIZE      (cast_int(100 * sizeof(TString)))
+#endif
 
 
 /*
 ** Possible states of the Garbage Collector
 */
-#define GCSpause        0
-#define GCSpropagate    1
+#define GCSpropagate    0
+#define GCSatomic       1
 #define GCSsweepstring  2
-#define GCSsweep        3
-#define GCSfinalize     4
+#define GCSsweepudata   3
+#define GCSsweep        4
+#define GCSpause        5
+
 
+#define issweepphase(g)  \
+        (GCSsweepstring <= (g)->gcstate && (g)->gcstate <= GCSsweep)
+
+#define isgenerational(g)       ((g)->gckind == KGC_GEN)
 
 /*
-** some userful bit tricks
+** macros to tell when main invariant (white objects cannot point to black
+** ones) must be kept. During a non-generational collection, the sweep
+** phase may break the invariant, as objects turned white may point to
+** still-black objects. The invariant is restored when sweep ends and
+** all objects are white again. During a generational collection, the
+** invariant must be kept all times.
 */
-#define resetbits(x,m)  ((x) &= cast(lu_byte, ~(m)))
-#define setbits(x,m)    ((x) |= (m))
-#define testbits(x,m)   ((x) & (m))
-#define bitmask(b)      (1<<(b))
-#define bit2mask(b1,b2) (bitmask(b1) | bitmask(b2))
-#define l_setbit(x,b)   setbits(x, bitmask(b))
-#define resetbit(x,b)   resetbits(x, bitmask(b))
-#define testbit(x,b)    testbits(x, bitmask(b))
-#define set2bits(x,b1,b2)       setbits(x, (bit2mask(b1, b2)))
-#define reset2bits(x,b1,b2)     resetbits(x, (bit2mask(b1, b2)))
-#define test2bits(x,b1,b2)      testbits(x, (bit2mask(b1, b2)))
 
+#define keepinvariant(g)        (isgenerational(g) || g->gcstate <= GCSatomic)
 
 
 /*
-** Layout for bit use in `marked' field:
-** bit 0 - object is white (type 0)
-** bit 1 - object is white (type 1)
-** bit 2 - object is black
-** bit 3 - for userdata: has been finalized
-** bit 3 - for tables: has weak keys
-** bit 4 - for tables: has weak values
-** bit 5 - object is fixed (should not be collected)
-** bit 6 - object is "super" fixed (only the main thread)
+** Outside the collector, the state in generational mode is kept in
+** 'propagate', so 'keepinvariant' is always true.
 */
+#define keepinvariantout(g)  \
+  check_exp(g->gcstate == GCSpropagate || !isgenerational(g),  \
+            g->gcstate <= GCSatomic)
+
 
+/*
+** some useful bit tricks
+*/
+#define resetbits(x,m)          ((x) &= cast(lu_byte, ~(m)))
+#define setbits(x,m)            ((x) |= (m))
+#define testbits(x,m)           ((x) & (m))
+#define bitmask(b)              (1<<(b))
+#define bit2mask(b1,b2)         (bitmask(b1) | bitmask(b2))
+#define l_setbit(x,b)           setbits(x, bitmask(b))
+#define resetbit(x,b)           resetbits(x, bitmask(b))
+#define testbit(x,b)            testbits(x, bitmask(b))
+
+
+/* Layout for bit use in `marked' field: */
+#define WHITE0BIT       0  /* object is white (type 0) */
+#define WHITE1BIT       1  /* object is white (type 1) */
+#define BLACKBIT        2  /* object is black */
+#define FINALIZEDBIT    3  /* object has been separated for finalization */
+#define SEPARATED       4  /* object is in 'finobj' list or in 'tobefnz' */
+#define FIXEDBIT        5  /* object is fixed (should not be collected) */
+#define OLDBIT          6  /* object is old (only in generational mode) */
+/* bit 7 is currently used by tests (luaL_checkmemory) */
 
-#define WHITE0BIT       0
-#define WHITE1BIT       1
-#define BLACKBIT        2
-#define FINALIZEDBIT    3
-#define KEYWEAKBIT      3
-#define VALUEWEAKBIT    4
-#define FIXEDBIT        5
-#define SFIXEDBIT       6
 #define WHITEBITS       bit2mask(WHITE0BIT, WHITE1BIT)
 
 
-#define iswhite(x)      test2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
+#define iswhite(x)      testbits((x)->gch.marked, WHITEBITS)
 #define isblack(x)      testbit((x)->gch.marked, BLACKBIT)
-#define isgray(x)       (!isblack(x) && !iswhite(x))
+#define isgray(x)  /* neither white nor black */  \
+        (!testbits((x)->gch.marked, WHITEBITS | bitmask(BLACKBIT)))
+
+#define isold(x)        testbit((x)->gch.marked, OLDBIT)
+
+/* MOVE OLD rule: whenever an object is moved to the beginning of
+   a GC list, its old bit must be cleared */
+#define resetoldbit(o)  resetbit((o)->gch.marked, OLDBIT)
 
 #define otherwhite(g)   (g->currentwhite ^ WHITEBITS)
-#define isdead(g,v)     ((v)->gch.marked & otherwhite(g) & WHITEBITS)
+#define isdeadm(ow,m)   (!(((m) ^ WHITEBITS) & (ow)))
+#define isdead(g,v)     isdeadm(otherwhite(g), (v)->gch.marked)
 
 #define changewhite(x)  ((x)->gch.marked ^= WHITEBITS)
 #define gray2black(x)   l_setbit((x)->gch.marked, BLACKBIT)
@@ -77,34 +119,39 @@
 #define luaC_white(g)   cast(lu_byte, (g)->currentwhite & WHITEBITS)
 
 
-#define luaC_checkGC(L) { \
-  condhardstacktests(luaD_reallocstack(L, L->stacksize - EXTRA_STACK - 1)); \
-  if (G(L)->totalbytes >= G(L)->GCthreshold) \
-        luaC_step(L); }
+#define luaC_condGC(L,c) \
+        {if (G(L)->GCdebt > 0) {c;}; condchangemem(L);}
+#define luaC_checkGC(L)         luaC_condGC(L, luaC_step(L);)
 
 
 #define luaC_barrier(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p)))  \
-        luaC_barrierf(L,obj2gco(p),gcvalue(v)); }
+        luaC_barrier_(L,obj2gco(p),gcvalue(v)); }
 
-#define luaC_barriert(L,t,v) { if (valiswhite(v) && isblack(obj2gco(t)))  \
-        luaC_barrierback(L,t); }
+#define luaC_barrierback(L,p,v) { if (valiswhite(v) && isblack(obj2gco(p)))  \
+        luaC_barrierback_(L,p); }
 
 #define luaC_objbarrier(L,p,o)  \
         { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
-                luaC_barrierf(L,obj2gco(p),obj2gco(o)); }
+                luaC_barrier_(L,obj2gco(p),obj2gco(o)); }
 
-#define luaC_objbarriert(L,t,o)  \
-   { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) luaC_barrierback(L,t); }
+#define luaC_objbarrierback(L,p,o)  \
+   { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) luaC_barrierback_(L,p); }
 
-LUAI_FUNC size_t luaC_separateudata (lua_State *L, int all);
-LUAI_FUNC void luaC_callGCTM (lua_State *L);
-LUAI_FUNC void luaC_freeall (lua_State *L);
-LUAI_FUNC void luaC_step (lua_State *L);
-LUAI_FUNC void luaC_fullgc (lua_State *L);
-LUAI_FUNC void luaC_link (lua_State *L, GCObject *o, lu_byte tt);
-LUAI_FUNC void luaC_linkupval (lua_State *L, UpVal *uv);
-LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v);
-LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t);
+#define luaC_barrierproto(L,p,c) \
+   { if (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);
+LUAI_FUNC void luaC_runtilstate (lua_State *L, int statesmask);
+LUAI_FUNC void luaC_fullgc (lua_State *L, int isemergency);
+LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz,
+                                 GCObject **list, int offset);
+LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v);
+LUAI_FUNC void luaC_barrierback_ (lua_State *L, GCObject *o);
+LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c);
+LUAI_FUNC void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt);
+LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv);
+LUAI_FUNC void luaC_changemode (lua_State *L, int mode);
 
 #endif