kernel: use custom GC marking for T_FUNCTION

Not all slots of a T_FUNCTION bag are filled with bag refs, yet when
marking the slots of such a bag during garbage collection, we still used
MarkAllSubBags. This is usually no problem with GASMAN, as it detects if
a pointer isn't a master pointer, and can then simply ignore it. But
other garbage collections can't as easily verify master pointers. So
let's try to be accurate about what we mark as a bag and what not: skip
the first eight slots of every T_FUNCTION bag for marking (they contain
pointers to C functions), and also ensure that the rest of any
T_FUNCTION bag only contains bag refs.

Also fix a bug in saving/restoring operations, where the 'enabled' field
was stored as an UInt, even though it now is an Obj (though we currently
only store immediate ints in it, hence there was no functional problem).

src/calls.c

@@ -957,6 +957,7 @@ Obj NewFunctionT (
     SET_NAME_FUNC(func, ConvImmString(name));
     SET_NARG_FUNC(func, narg);
     SET_NAMS_FUNC(func, nams);
+    SET_NLOC_FUNC(func, 0);
     if (nams) MakeBagPublic(nams);
     CHANGED_BAG(func);
 
@@ -1547,6 +1548,7 @@ Obj FuncPROFILE_FUNC(
         SET_NARG_FUNC(copy,   NARG_FUNC(func));
         SET_NAMS_FUNC(copy,   NAMS_FUNC(func));
         SET_PROF_FUNC(copy,   PROF_FUNC(func));
+        SET_NLOC_FUNC(copy,   NLOC_FUNC(func));
         SET_HDLR_FUNC(func,0, DoProf0args);
         SET_HDLR_FUNC(func,1, DoProf1args);
         SET_HDLR_FUNC(func,2, DoProf2args);
@@ -1730,14 +1732,14 @@ static ObjFunc LoadHandler( void )
 */
 void SaveFunction ( Obj func )
 {
-  FuncBag * header = FUNC(func);
+  const FuncBag * header = CONST_FUNC(func);
   for (UInt i = 0; i <= 7; i++)
     SaveHandler(header->handlers[i]);
   SaveSubObj(header->name);
-  SaveUInt(header->nargs);
+  SaveSubObj(header->nargs);
   SaveSubObj(header->namesOfLocals);
   SaveSubObj(header->prof);
-  SaveUInt(header->nloc);
+  SaveSubObj(header->nloc);
   SaveSubObj(header->body);
   SaveSubObj(header->envi);
   SaveSubObj(header->fexs);
@@ -1756,10 +1758,10 @@ void LoadFunction ( Obj func )
   for (UInt i = 0; i <= 7; i++)
     header->handlers[i] = LoadHandler();
   header->name = LoadSubObj();
-  header->nargs = LoadUInt();
+  header->nargs = LoadSubObj();
   header->namesOfLocals = LoadSubObj();
   header->prof = LoadSubObj();
-  header->nloc = LoadUInt();
+  header->nloc = LoadSubObj();
   header->body = LoadSubObj();
   header->envi = LoadSubObj();
   header->fexs = LoadSubObj();
@@ -1769,6 +1771,21 @@ void LoadFunction ( Obj func )
 
 #endif
 
+/****************************************************************************
+**
+*F  MarkFunctionSubBags( <bag> ) . . . . . . . marking function for functions
+**
+**  'MarkFunctionSubBags' is the marking function for bags of type 'T_FUNCTION'.
+*/
+void MarkFunctionSubBags(Obj func)
+{
+    // the first eight slots are pointers to C functions, so we need
+    // to skip those for marking
+    UInt size = SIZE_BAG(func) / sizeof(Obj) - 8;
+    const Bag * data = CONST_PTR_BAG(func) + 8;
+    MarkArrayOfBags(data, size);
+}
+
 
 /****************************************************************************
 **
@@ -1836,7 +1853,7 @@ static Int InitKernel (
 
     /* install the marking functions                                       */
     InfoBags[ T_FUNCTION ].name = "function";
-    InitMarkFuncBags( T_FUNCTION , MarkAllSubBags );
+    InitMarkFuncBags(T_FUNCTION, MarkFunctionSubBags);
 
     /* Allocate functions in the public region */
     MakeBagTypePublic(T_FUNCTION);

src/calls.h

@@ -107,10 +107,10 @@ typedef Obj (* ObjFunc_6ARGS) (Obj self, Obj a1, Obj a2, Obj a3, Obj a4, Obj a5,
 typedef struct {
     ObjFunc handlers[8];
     Obj name;
-    Int nargs;
+    Obj nargs;
     Obj namesOfLocals;
     Obj prof;
-    UInt nloc;
+    Obj nloc;
     Obj body;
     Obj envi;
     Obj fexs;
@@ -146,7 +146,7 @@ static inline Obj NAME_FUNC(Obj func)
 
 static inline Int NARG_FUNC(Obj func)
 {
-    return CONST_FUNC(func)->nargs;
+    return INT_INTOBJ(CONST_FUNC(func)->nargs);
 }
 
 static inline Obj NAMS_FUNC(Obj func)
@@ -163,7 +163,7 @@ static inline Obj PROF_FUNC(Obj func)
 
 static inline UInt NLOC_FUNC(Obj func)
 {
-    return CONST_FUNC(func)->nloc;
+    return INT_INTOBJ(CONST_FUNC(func)->nloc);
 }
 
 static inline Obj BODY_FUNC(Obj func)
@@ -199,7 +199,7 @@ extern void SET_NAME_FUNC(Obj func, Obj name);
 
 static inline void SET_NARG_FUNC(Obj func, Int nargs)
 {
-    FUNC(func)->nargs = nargs;
+    FUNC(func)->nargs = INTOBJ_INT(nargs);
 }
 
 static inline void SET_NAMS_FUNC(Obj func, Obj namesOfLocals)
@@ -214,7 +214,7 @@ static inline void SET_PROF_FUNC(Obj func, Obj prof)
 
 static inline void SET_NLOC_FUNC(Obj func, UInt nloc)
 {
-    FUNC(func)->nloc = nloc;
+    FUNC(func)->nloc = INTOBJ_INT(nloc);
 }
 
 static inline void SET_BODY_FUNC(Obj func, Obj body)

src/opers.c

@@ -3313,22 +3313,22 @@ void InstallGlobalFunction (
 void SaveOperationExtras (
     Obj         oper )
 {
-    UInt        i;
-
-    SaveSubObj(FLAG1_FILT(oper));
-    SaveSubObj(FLAG2_FILT(oper));
-    SaveSubObj(FLAGS_FILT(oper));
-    SaveSubObj(SETTR_FILT(oper));
-    SaveSubObj(TESTR_FILT(oper));
-    SaveUInt(ENABLED_ATTR(oper));
-    for (i = 0; i <= 7; i++)
-        SaveSubObj(METHS_OPER(oper,i));
+    const OperBag * header = CONST_OPER(oper);
+
+    SaveSubObj(header->flag1);
+    SaveSubObj(header->flag2);
+    SaveSubObj(header->flags);
+    SaveSubObj(header->setter);
+    SaveSubObj(header->tester);
+    SaveSubObj(header->enabled);
+    for (UInt i = 0; i <= 7; i++)
+        SaveSubObj(header->methods[i]);
 #ifdef HPCGAP
     // FIXME: We probably don't want to save/restore the cache?
     // (and that would include "normal" GAP, too...)
 #else
-    for (i = 0; i <= 7; i++)
-        SaveSubObj(CACHE_OPER(oper,i));
+    for (UInt i = 0; i <= 7; i++)
+        SaveSubObj(header->cache[i]);
 #endif
 }
 
@@ -3344,23 +3344,22 @@ void SaveOperationExtras (
 void LoadOperationExtras (
     Obj         oper )
 {
-    UInt        i;
-
-    SET_FLAG1_FILT(oper, LoadSubObj());
-    SET_FLAG2_FILT(oper, LoadSubObj());
-    SET_FLAGS_FILT(oper, LoadSubObj());
-    SET_SETTR_FILT(oper, LoadSubObj());
-    SET_TESTR_FILT(oper, LoadSubObj());
-    i = LoadUInt();
-    SET_ENABLED_ATTR(oper,i);
-    for (i = 0; i <= 7; i++)
-        SET_METHS_OPER(oper, i, LoadSubObj());
+    OperBag * header = OPER(oper);
+
+    header->flag1 = LoadSubObj();
+    header->flag2 = LoadSubObj();
+    header->flags = LoadSubObj();
+    header->setter = LoadSubObj();
+    header->tester = LoadSubObj();
+    header->enabled = LoadSubObj();
+    for (UInt i = 0; i <= 7; i++)
+        header->methods[i] = LoadSubObj();
 #ifdef HPCGAP
     // FIXME: We probably don't want to save/restore the cache?
     // (and that would include "normal" GAP, too...)
 #else
-    for (i = 0; i <= 7; i++)
-        SET_CACHE_OPER(oper, i, LoadSubObj());
+    for (UInt i = 0; i <= 7; i++)
+        header->cache[i] = LoadSubObj();
 #endif
 }