/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: agc.c *
* Last rev: *
* mods: *
* comments: reclaim unused atoms and functors *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "@(#)agc.c 1.3 3/15/90";
#endif
#include "absmi.h"
#include "alloc.h"
#include "yapio.h"
#ifdef DEBUG
/* #define DEBUG_RESTORE2 1 */
#define errout Yap_stderr
#endif
STATIC_PROTO(void RestoreEntries, (PropEntry *));
STATIC_PROTO(void ConvDBList, (Term, char *,CELL));
static int agc_calls;
static Int agc_collected;
static Int tot_agc_time = 0; /* total time spent in GC */
static Int tot_agc_recovered = 0; /* number of heap objects in all garbage collections */
#define AtomMarkedBit 1
static inline void
MarkAtomEntry(AtomEntry *ae)
{
CELL c = (CELL)(ae->NextOfAE);
c |= AtomMarkedBit;
ae->NextOfAE = (Atom)c;
}
static inline int
AtomResetMark(AtomEntry *ae)
{
CELL c = (CELL)(ae->NextOfAE);
if (c & AtomMarkedBit) {
c &= ~AtomMarkedBit;
ae->NextOfAE = (Atom)c;
return (TRUE);
}
return (FALSE);
}
static inline Atom
CleanAtomMarkedBit(Atom a)
{
CELL c = (CELL)a;
c &= ~AtomMarkedBit;
return((Atom)c);
}
static inline Functor
FuncAdjust(Functor f)
{
AtomEntry *ae = RepAtom(NameOfFunctor(f));
MarkAtomEntry(ae);
return(f);
}
static inline Term
AtomTermAdjust(Term t)
{
AtomEntry *ae = RepAtom(AtomOfTerm(t));
MarkAtomEntry(ae);
return(t);
}
static inline Atom
AtomAdjust(Atom a)
{
AtomEntry *ae;
if (a == NIL) return(a);
ae = RepAtom(a);
MarkAtomEntry(ae);
return(a);
}
#define HDiff TRUE
#define OldHeapTop HeapTop
#define IsOldCode(P) FALSE
#define IsOldCodeCellPtr(P) FALSE
#define IsOldDelay(P) FALSE
#define IsOldDelayPtr(P) FALSE
#define IsOldLocalInTR(P) FALSE
#define IsOldLocalInTRPtr(P) FALSE
#define IsOldGlobal(P) FALSE
#define IsOldGlobalPtr(P) FALSE
#define IsOldTrail(P) FALSE
#define IsOldTrailPtr(P) FALSE
#define CharP(X) ((char *)(X))
#define AddrAdjust(P) (P)
#define AtomEntryAdjust(P) (P)
#define BlobTermAdjust(P) (P)
#define CellPtoHeapAdjust(P) (P)
#define CellPtoHeapCellAdjust(P) (P)
#define CellPtoTRAdjust(P) (P)
#define CodeAddrAdjust(P) (P)
#define ConsultObjAdjust(P) (P)
#define DelayAddrAdjust(P) (P)
#define DBRefAdjust(P) (P)
#define DBRefPAdjust(P) (P)
#define LocalAddrAdjust(P) (P)
#define GlobalAddrAdjust(P) (P)
#define PtoArrayEAdjust(P) (P)
#define PtoDelayAdjust(P) (P)
#define PtoGloAdjust(P) (P)
#define PtoLocAdjust(P) (P)
#define PtoHeapCellAdjust(P) (P)
#define PtoOpAdjust(P) (P)
#define PtoPredAdjust(P) (P)
#define PropAdjust(P) (P)
#define TrailAddrAdjust(P) (P)
#define XAdjust(P) (P)
#define YAdjust(P) (P)
static void
recompute_mask(DBRef dbr)
{
return;
}
static void
rehash(CELL *oldcode, int NOfE, int KindOfEntries)
{
}
#include "rheap.h"
/*
* This is the really tough part, to restore the whole of the heap
*/
static void
mark_atoms(void)
{
AtomHashEntry *HashPtr = HashChain;
register int i;
Atom atm;
AtomEntry *at;
restore_codes();
for (i = 0; i < MaxHash; ++i) {
atm = HashPtr->Entry;
if (atm) {
at = RepAtom(atm);
do {
#ifdef DEBUG_RESTORE2 /* useful during debug */
fprintf(errout, "Restoring %s\n", at->StrOfAE);
#endif
RestoreEntries(RepProp(at->PropsOfAE));
atm = at->NextOfAE;
at = RepAtom(CleanAtomMarkedBit(atm));
} while (!EndOfPAEntr(at));
}
HashPtr++;
}
atm = INVISIBLECHAIN.Entry;
at = RepAtom(atm);
if (EndOfPAEntr(at)) {
return;
}
do {
#ifdef DEBUG_RESTORE2 /* useful during debug */
fprintf(errout, "Restoring %s\n", at->StrOfAE);
if (strcmp(at->StrOfAE,"$module_expansion") == 0) {
printf("oops\n");
}
#endif
RestoreEntries(RepProp(at->PropsOfAE));
atm = at->NextOfAE;
at = RepAtom(CleanAtomMarkedBit(atm));
} while (!EndOfPAEntr(at));
}
static void
mark_trail(void)
{
register CELL *pt;
pt = (CELL *)TR;
/* moving the trail is simple */
while (pt != (CELL *)Yap_TrailBase) {
register CELL reg = pt[-1];
pt--;
if (!IsVarTerm(reg)) {
if (IsAtomTerm(reg)) {
MarkAtomEntry(RepAtom(AtomOfTerm(reg)));
}
}
}
}
static void
mark_local(void)
{
register CELL *pt;
/* Adjusting the local */
pt = LCL0;
/* moving the trail is simple */
while (pt > ASP) {
CELL reg = *--pt;
if (!IsVarTerm(reg)) {
if (IsAtomTerm(reg)) {
MarkAtomEntry(RepAtom(AtomOfTerm(reg)));
}
}
}
}
static void
mark_global(void)
{
register CELL *pt;
/*
* to clean the global now that functors are just variables pointing to
* the code
*/
pt = CellPtr(Yap_GlobalBase);
while (pt < H) {
register CELL reg;
reg = *pt;
if (IsVarTerm(reg)) {
pt++;
continue;
} else if (IsAtomTerm(reg)) {
MarkAtomEntry(RepAtom(AtomOfTerm(reg)));
} else if (IsApplTerm(reg)) {
Functor f = FunctorOfTerm(reg);
if (f <= FunctorDouble && f >= FunctorLongInt) {
/* skip bitmaps */
switch((CELL)f) {
case (CELL)FunctorDouble:
#if SIZEOF_DOUBLE == 2*SIZEOF_LONG_INT
pt += 3;
#else
pt += 2;
#endif
break;
#if USE_GMP
case (CELL)FunctorBigInt:
{
Int sz = 1+
sizeof(MP_INT)+
(((MP_INT *)(pt+1))->_mp_alloc*sizeof(mp_limb_t));
pt += sz;
}
break;
#endif
case (CELL)FunctorLongInt:
default:
pt += 2;
break;
}
}
}
pt++;
}
}
static void
mark_stacks(void)
{
mark_trail();
mark_local();
mark_global();
}
/*
* This is the really tough part, to restore the whole of the heap
*/
static void
clean_atoms(void)
{
AtomHashEntry *HashPtr = HashChain;
register int i;
Atom atm;
Atom *patm;
AtomEntry *at;
for (i = 0; i < MaxHash; ++i) {
atm = HashPtr->Entry;
patm = &(HashPtr->Entry);
while (atm != NIL) {
at = RepAtom(CleanAtomMarkedBit(atm));
if (AtomResetMark(at) || (AGCHook != NULL && !AGCHook(atm))) {
patm = &(at->NextOfAE);
atm = at->NextOfAE;
} else {
#ifdef DEBUG_RESTORE2
fprintf(stderr, "Purged %s\n", at->StrOfAE);
#endif
*patm = at->NextOfAE;
atm = at->NextOfAE;
agc_collected += Yap_SizeOfBlock((CODEADDR)at);
Yap_FreeCodeSpace((char *)at);
}
}
HashPtr++;
}
patm = &(INVISIBLECHAIN.Entry);
atm = INVISIBLECHAIN.Entry;
while (atm != NIL) {
at = RepAtom(CleanAtomMarkedBit(atm));
if (AtomResetMark(at) || (AGCHook != NULL && !AGCHook(atm))) {
patm = &(atm->NextOfAE);
atm = at->NextOfAE;
} else {
#ifdef DEBUG_RESTORE2
fprintf(stderr, "Purged %s\n", at->StrOfAE);
#endif
*patm = at->NextOfAE;
atm = at->NextOfAE;
agc_collected += Yap_SizeOfBlock((CODEADDR)at);
Yap_FreeCodeSpace((char *)at);
}
}
}
static void
atom_gc(void)
{
int gc_verbose = Yap_is_gc_verbose();
int gc_trace = 0;
Int time_start, agc_time;
if (Yap_GetValue(AtomGcTrace) != TermNil)
gc_trace = 1;
agc_calls++;
agc_collected = 0;
if (gc_trace) {
fprintf(Yap_stderr, "[agc]\n");
} else if (gc_verbose) {
fprintf(Yap_stderr, "[AGC] Start of atom garbage collection %d:\n", agc_calls);
}
time_start = Yap_cputime();
/* get the number of active registers */
YAPEnterCriticalSection();
mark_stacks();
mark_atoms();
clean_atoms();
YAPLeaveCriticalSection();
agc_time = Yap_cputime()-time_start;
tot_agc_time += agc_time;
tot_agc_recovered += agc_collected;
if (gc_verbose) {
fprintf(Yap_stderr, "[AGC] collected %d bytes.\n", agc_collected);
fprintf(Yap_stderr, "[AGC] GC %d took %g sec, total of %g sec doing GC so far.\n", agc_calls, (double)agc_time/1000, (double)tot_agc_time/1000);
}
}
void
Yap_atom_gc(void)
{
atom_gc();
}
static Int
p_atom_gc(void)
{
#ifndef FIXED_STACKS
atom_gc();
#endif /* FIXED_STACKS */
return(TRUE);
}
static Int
p_inform_agc(void)
{
Term tn = MkIntegerTerm(tot_agc_time);
Term tt = MkIntegerTerm(agc_calls);
Term ts = MkIntegerTerm(tot_agc_recovered);
return(Yap_unify(tn, ARG2) && Yap_unify(tt, ARG1) && Yap_unify(ts, ARG3));
}
void
Yap_init_agc(void)
{
Yap_InitCPred("$atom_gc", 0, p_atom_gc, 0);
Yap_InitCPred("$inform_agc", 3, p_inform_agc, 0);
}