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da817ebbe5
yap-6.3/C/heapgc.c

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This commit was generated by cvs2svn to compensate for changes in r4, which included commits to RCS files with non-trunk default branches. git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@5 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
2001-04-09 20:54:03 +01:00
/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: heapgc.c *
* Last rev: *
* mods: *
* comments: Global Stack garbage collector *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif /* SCCS */
#include "absmi.h"
#include "yapio.h"
/* #define SIMPLE_SHUNTING 1 */
#ifdef MULTI_ASSIGNMENT_VARIABLES
/*
Based in opt.mavar.h. This is a set of routines to find out if a
ma trail entry has appeared before in the same trail segment. All ma
entries for the same cell are then linked. At the end of mark_trail() only
one will remain.
*/
#define GC_MAVARS_HASH_SIZE 512
typedef struct gc_ma_h_entry {
CELL* addr;
tr_fr_ptr trptr;
struct gc_ma_h_entry* ma_list;
struct gc_ma_h_entry *next;
} gc_ma_h_inner_struct;
extern struct gc_ma_h_entry *live_list;
typedef struct {
UInt timestmp;
struct gc_ma_h_entry val;
} gc_ma_hash_entry;
static gc_ma_hash_entry gc_ma_hash_table[GC_MAVARS_HASH_SIZE];
static UInt timestamp; /* an unsigned int */
static inline unsigned int
GC_MAVAR_HASH(CELL *addr) {
#if SIZEOF_INT_P==8
return((((unsigned int)((CELL)(addr)))>>3)%GC_MAVARS_HASH_SIZE);
#else
return((((unsigned int)((CELL)(addr)))>>2)%GC_MAVARS_HASH_SIZE);
#endif
}
gc_ma_h_inner_struct *gc_ma_h_top;
static inline struct gc_ma_h_entry *
GC_ALLOC_NEW_MASPACE(void)
{
gc_ma_h_inner_struct *new = gc_ma_h_top;
if ((char *)gc_ma_h_top > TrailTop-1024)
growtrail(64 * 1024L);
gc_ma_h_top++;
return(new);
}
static inline tr_fr_ptr*
gc_lookup_ma_var(CELL *addr, tr_fr_ptr trp) {
unsigned int i = GC_MAVAR_HASH(addr);
struct gc_ma_h_entry *nptr, *optr;
if (gc_ma_hash_table[i].timestmp != timestamp) {
gc_ma_hash_table[i].timestmp = timestamp;
gc_ma_hash_table[i].val.addr = addr;
gc_ma_hash_table[i].val.next = NULL;
gc_ma_hash_table[i].val.trptr = trp;
gc_ma_hash_table[i].val.ma_list = live_list;
live_list = &(gc_ma_hash_table[i].val);
return(NULL);
}
if (gc_ma_hash_table[i].val.addr == addr)
return(&(gc_ma_hash_table[i].val.trptr));
optr = &(gc_ma_hash_table[i].val);
nptr = gc_ma_hash_table[i].val.next;
while (nptr != NULL) {
if (nptr->addr == addr) {
return(&(nptr->trptr));
}
optr = nptr;
nptr = nptr->next;
}
nptr = GC_ALLOC_NEW_MASPACE();
nptr->addr = addr;
nptr->next = optr;
nptr->trptr = trp;
nptr->ma_list = live_list;
live_list = nptr;
return(NULL);
}
static inline void
GC_NEW_MAHASH(gc_ma_h_inner_struct *top) {
UInt time = ++timestamp;
if (time == 0) {
unsigned int i;
/* damn, we overflowed */
for (i = 0; i < GC_MAVARS_HASH_SIZE; i++)
gc_ma_hash_table[i].timestmp = 0;
time = ++timestamp;
}
gc_ma_h_top = top;
live_list = NULL;
}
#endif
/* #define DB_SEARCH_METHOD 1 */
/* global variables for garbage collection */
#ifndef DEBUG
static
#endif
unsigned int gc_calls = 0; /* number of times GC has been called */
static CELL tot_gc_time = 0; /* total time spent in GC */
/* in a single gc */
UInt total_marked; /* number of heap objects marked */
struct gc_ma_h_entry *live_list;
STATIC_PROTO(Int p_inform_gc, (void));
STATIC_PROTO(Int p_gc, (void));
#ifndef FIXED_STACKS
#ifdef SIMPLE_SHUNTING
static choiceptr current_B;
#endif
STATIC_PROTO(void push_registers, (Int, yamop *));
STATIC_PROTO(void marking_phase, (tr_fr_ptr, CELL *, yamop *, CELL *));
STATIC_PROTO(void compaction_phase, (tr_fr_ptr, CELL *, yamop *, CELL *));
STATIC_PROTO(void pop_registers, (Int, yamop *));
#if DB_SEARCH_METHOD
#else
STATIC_PROTO(void store_ref_in_dbtable, (DBRef));
STATIC_PROTO(DBRef find_ref_in_dbtable, (DBRef));
#endif
STATIC_PROTO(void init_dbtable, (tr_fr_ptr));
STATIC_PROTO(void mark_db_fixed, (CELL *));
STATIC_PROTO(void mark_regs, (tr_fr_ptr));
STATIC_PROTO(void mark_trail, (tr_fr_ptr, tr_fr_ptr, CELL *, choiceptr));
STATIC_PROTO(void mark_environments, (CELL *, OPREG, CELL *));
STATIC_PROTO(void mark_choicepoints, (choiceptr, tr_fr_ptr));
STATIC_PROTO(void into_relocation_chain, (CELL *, CELL *));
STATIC_PROTO(void sweep_trail, (choiceptr, tr_fr_ptr));
STATIC_PROTO(void sweep_environments, (CELL *, OPREG, CELL *));
STATIC_PROTO(void sweep_choicepoints, (choiceptr));
STATIC_PROTO(choiceptr update_B_H, (choiceptr, CELL *, CELL *, CELL *));
STATIC_PROTO(void compact_heap, (void));
STATIC_PROTO(void update_relocation_chain, (CELL *, CELL *));
static Int tot_gc_recovered = 0; /* number of heap objects in all garbage collections */
#include "heapgc.h"
static int discard_trail_entries = 0;
/* find all accessible objects on the heap and squeeze out all the rest */
/* push the active registers onto the trail for inclusion during gc */
static void
push_registers(Int num_regs, yamop *nextop)
{
int i;
#ifdef COROUTINING
TrailTerm(TR) = WokenGoals;
TrailTerm(TR+1) = MutableList;
TrailTerm(TR+2) = AttsMutableList;
TrailTerm(TR+3) = DelayedVars;
TR += 4;
#endif
for (i = 1; i <= num_regs; i++)
TrailTerm(TR++) = (CELL) XREGS[i];
/* push any live registers we might have hanging around */
if (nextop->opc == opcode(_move_back) ||
nextop->opc == opcode(_skip)) {
CELL *lab = (CELL *)(nextop->u.l.l);
CELL max = lab[0];
Int curr = lab[1];
lab += 2;
if (max) {
CELL i;
for (i=0L; i <= max; i++) {
if (i == 8*CellSize) {
curr = lab[0];
lab++;
}
if (curr & 1) {
TrailTerm(TR++) = XREGS[i];
}
curr >>= 1;
}
}
}
}
/* pop the corrected register values from the trail and update the registers */
static void
pop_registers(Int num_regs, yamop *nextop)
{
int i;
tr_fr_ptr ptr = TR;
#ifdef COROUTINING
#ifdef MULTI_ASSIGNMENT_VARIABLES
WokenGoals = TrailTerm(ptr++);
MutableList = TrailTerm(ptr++);
AttsMutableList = TrailTerm(ptr++);
DelayedVars = TrailTerm(ptr++);
#endif
#endif
for (i = 1; i <= num_regs; i++)
XREGS[i] = TrailTerm(ptr++);
/* pop any live registers we might have hanging around */
if (nextop->opc == opcode(_move_back) ||
nextop->opc == opcode(_skip)) {
CELL *lab = (CELL *)(nextop->u.l.l);
CELL max = lab[0];
Int curr = lab[1];
lab += 2;
if (max) {
CELL i;
for (i=0L; i <= max; i++) {
if (i == 8*CellSize) {
curr = lab[0];
lab++;
}
if (curr & 1) {
XREGS[i] = TrailTerm(ptr++);
}
curr >>= 1;
}
}
}
}
#ifdef DEBUG
static int
count_cells_marked(void)
{
CELL *current;
int found_marked = 0;
for (current = H - 1; current >= H0; current--) {
if (MARKED(*current)) {
found_marked++;
}
}
return(found_marked);
}
#endif
#if DB_SEARCH_METHOD
/* In this method we store first pointers to the DB, and when we find an entry
in the trail we go and see if anyone is pointing at it. We try to be efficient
space-wise, by removing entries to code that does not need them
*/
typedef struct DB_entry {
CELL *addr;
struct DB_entry *next;
} *dbentry;
#define MAX_DB_ENTRIES 1024
static dbentry db_vec, free_entries;
static dbentry dbtable[MAX_DB_ENTRIES];
static int dbscale;
static CODEADDR MyHpBase;
static int
dbslot(CELL *ptr)
{
return((Addr(ptr)-Addr(MyHpBase))/dbscale);
}
static dbentry
new_dbvec_entry(void)
{
dbentry val;
if (free_entries != NULL) {
val = free_entries;
free_entries = free_entries->next;
return(val);
}
val = db_vec;
db_vec++;
return(val);
}
static void
add_new_dbuse(CELL *ptr)
{
int off = dbslot(ptr);
dbentry prev = NULL;
dbentry curr = dbtable[off];
while (curr != NULL && curr->addr < ptr) {
prev = curr;
curr = curr->next;
}
if (curr == NULL) {
dbentry db_entry = new_dbvec_entry();
db_entry->addr = ptr;
db_entry->next = NULL;
dbtable[off] = db_entry;
return;
} else if (curr->addr > ptr) {
dbentry db_entry = new_dbvec_entry();
db_entry->addr = ptr;
db_entry->next = curr;
if (prev == NULL) {
dbtable[off] = db_entry;
} else {
prev->next = db_entry;
}
}
}
static void
mark_db_fixed(CELL *trail_ptr) {
add_new_dbuse(trail_ptr);
}
/* there are two cases: either off0 == offf or offf > off0 */
static int
found_dbentries(CELL *beg, CELL *end)
{
int off0 = dbslot(beg);
int offf = dbslot(end);
int off = off0;
int found = FALSE;
dbentry prev = NULL;
dbentry curr = dbtable[off];
while (curr != NULL && curr->addr < beg) {
prev = curr;
curr = curr->next;
}
do {
while (curr != NULL) {
if (curr->addr > end) {
return(found);
} else {
dbentry nexte = curr->next;
found = TRUE;
if (prev == NULL)
dbtable[off] = nexte;
else
prev->next = nexte;
curr->next = free_entries;
free_entries = curr;
curr = nexte;
}
}
if (off < offf) {
off++;
prev = NULL;
curr = dbtable[off];
} else
return(found);
} while (TRUE);
}
#else
/* straightforward binary tree scheme that, given a key, finds a
matching dbref */
typedef struct db_entry {
DBRef val;
struct db_entry *left;
CELL *lim;
struct db_entry *right;
} *dbentry;
static dbentry db_vec, db_vec0;
/* init the table */
static void
store_ref_in_dbtable(DBRef entry)
{
dbentry parent = db_vec0;
dbentry new = db_vec;
if ((ADDR)new > TrailTop-1024)
growtrail(64 * 1024L);
new->val = entry;
new->lim = entry->Contents+entry->NOfCells;
new->left = new->right = NULL;
if (db_vec == db_vec0) {
db_vec++;
return;
}
db_vec++;
parent = db_vec0;
beg:
if (entry < parent->val) {
if (parent->right == NULL) {
parent->right = new;
} else {
parent = parent->right;
goto beg;
}
} else {
if (parent->left == NULL) {
parent->left = new;
} else {
parent = parent->left;
goto beg;
}
}
}
/* find an element in the dbentries table */
static DBRef
find_ref_in_dbtable(DBRef entry)
{
dbentry current = db_vec0;
while (current != NULL) {
if (current->val < entry && current->lim > (CELL *)entry)
return(current->val);
if (entry < current->val)
current = current->right;
else
current = current->left;
}
return(NULL);
}
static void
mark_db_fixed(CELL *ptr) {
DBRef el;
el = find_ref_in_dbtable((DBRef)ptr);
if (el != NULL)
el->Flags |= GcFoundMask;
}
#endif
static void
init_dbtable(tr_fr_ptr trail_ptr) {
#if DB_SEARCH_METHOD
MyHpBase = HeapBase;
db_vec = (dbentry)TR;
free_entries = NULL;
dbscale = ((Addr(HeapTop)-Addr(MyHpBase))+MAX_DB_ENTRIES-1)/MAX_DB_ENTRIES;
#else
db_vec0 = db_vec = (dbentry)TR;
while (trail_ptr > (tr_fr_ptr)TrailBase) {
register CELL trail_cell;
trail_ptr--;
trail_cell = TrailTerm(trail_ptr);
if (!IsVarTerm(trail_cell) && IsPairTerm(trail_cell)) {
CELL *pt0 = RepPair(trail_cell);
/* DB pointer */
CELL flags;
#ifdef FROZEN_REGS /* TRAIL */
/* avoid frozen segments */
if (
#ifdef SBA
(ADDR) pt0 >= HeapTop
#else
(ADDR) pt0 >= TrailBase
#endif
) {
continue;
}
#endif /* FROZEN_REGS */
flags = Flags((CELL)pt0);
/* for the moment, if all references to the term in the stacks
are only pointers, reset the flag */
if (FlagOn(DBClMask, flags) && !FlagOn(LogUpdMask, flags)) {
if (FlagOn(DBNoVars, flags)) {
CODEADDR entry = ((CODEADDR)pt0 - (CELL) &(((DBRef) NIL)->Flags));
store_ref_in_dbtable((DBRef)entry);
}
}
}
}
if (db_vec == db_vec0) {
/* could not find any entries: probably using LOG UPD semantics */
db_vec0 = NULL;
}
#endif
}
#ifdef DEBUG
#define INSTRUMENT_GC 1
#ifdef INSTRUMENT_GC
typedef enum {
gc_var,
gc_ref,
gc_atom,
gc_int,
gc_num,
gc_list,
gc_appl,
gc_func,
gc_susp
} gc_types;
unsigned long chain[16];
unsigned long env_vars;
unsigned long vars[gc_susp+1];
unsigned long num_bs;
unsigned long old_vars, new_vars;
static CELL *TrueHB;
static void
inc_vars_of_type(CELL *curr,gc_types val) {
if (curr >= H0 && curr < TrueHB) {
old_vars++;
} else if (curr >= TrueHB && curr < H) {
new_vars++;
} else {
return;
}
vars[val]++;
}
static void
put_type_info(unsigned long total)
{
YP_fprintf(YP_stderr,"[GC] type info for %lu cells\n", total);
YP_fprintf(YP_stderr,"[GC] %lu vars\n", vars[gc_var]);
YP_fprintf(YP_stderr,"[GC] %lu refs\n", vars[gc_ref]);
YP_fprintf(YP_stderr,"[GC] %lu references from env\n", env_vars);
YP_fprintf(YP_stderr,"[GC] %lu atoms\n", vars[gc_atom]);
YP_fprintf(YP_stderr,"[GC] %lu small ints\n", vars[gc_int]);
YP_fprintf(YP_stderr,"[GC] %lu other numbers\n", vars[gc_num]);
YP_fprintf(YP_stderr,"[GC] %lu lists\n", vars[gc_list]);
YP_fprintf(YP_stderr,"[GC] %lu compound terms\n", vars[gc_appl]);
YP_fprintf(YP_stderr,"[GC] %lu functors\n", vars[gc_func]);
YP_fprintf(YP_stderr,"[GC] %lu suspensions\n", vars[gc_susp]);
}
static void
inc_var(CELL *current, CELL *next)
{
int len = 1;
CELL *mynext=next;
if (ONHEAP(current)) {
if (next == current) {
inc_vars_of_type(current,gc_var);
chain[0]++;
} else {
inc_vars_of_type(current,gc_ref);
while(ONHEAP(mynext) && IsVarTerm(*mynext)) {
CELL *prox = GET_NEXT(*mynext);
if (prox == mynext) {
chain[0]++;
break;
}
len++;
mynext = prox;
}
if (len>=15)
(chain[15])++;
else
(chain[len])++;
}
}
}
#endif /* INSTRUMENT_GC */
int STD_PROTO(vsc_stop,(void));
int
vsc_stop(void) {
return(1);
}
static void
check_global(void) {
CELL *current;
#ifdef INSTRUMENT_GC
vars[gc_var] = 0;
vars[gc_ref] = 0;
vars[gc_atom] = 0;
vars[gc_int] = 0;
vars[gc_num] = 0;
vars[gc_list] = 0;
vars[gc_appl] = 0;
vars[gc_func] = 0;
vars[gc_susp] = 0;
#endif
for (current = H - 1; current >= H0; current--) {
CELL ccurr = *current;
if (MARKED(ccurr)) {
CELL ccell = UNMARK_CELL(ccurr);
if (ccell < (CELL)AtomBase && ccell > EndSpecials && IsVarTerm(ccell)) {
/* oops, we found a blob */
int nofcells = (UNMARK_CELL(*current)-EndSpecials) / sizeof(CELL);
CELL *ptr = current - nofcells ;
current = ptr;
ccurr = *current;
/* process the functor next */
}
if (MARKED(ccurr)) {
printf("Oops, found marked cell at %p\n", current);
break;
}
}
#if INSTRUMENT_GC
if (IsVarTerm(ccurr)) {
if (IsBlobFunctor((Functor)ccurr)) vars[gc_num]++;
else if (ccurr != 0 && ccurr < (CELL)HeapTop) vars[gc_func]++;
else if (IsUnboundVar((CELL)current)) vars[gc_var]++;
else vars[gc_ref]++;
} else if (IsApplTerm(ccurr)) {
vars[gc_appl]++;
} else if (IsPairTerm(ccurr)) {
vars[gc_list]++;
} else if (IsAtomTerm(ccurr)) {
vars[gc_atom]++;
} else if (IsIntTerm(ccurr)) {
vars[gc_int]++;
}
#endif
}
#if INSTRUMENT_GC
put_type_info(H-H0);
vars[gc_var] = 0;
vars[gc_ref] = 0;
vars[gc_atom] = 0;
vars[gc_int] = 0;
vars[gc_num] = 0;
vars[gc_list] = 0;
vars[gc_appl] = 0;
vars[gc_func] = 0;
vars[gc_susp] = 0;
#endif
}
#endif
/* mark a heap object and all heap objects accessible from it */
void
mark_variable(CELL_PTR current)
{
CELL_PTR next;
register CELL ccur;
unsigned int arity;
unsigned int i;
begin:
ccur = *current;
if (MARKED(ccur))
return;
MARK(current);
total_marked++;
next = GET_NEXT(ccur);
if (IsVarTerm(ccur)) {
if (ONHEAP(next)) {
#ifdef SIMPLE_SHUNTING
CELL cnext;
/* do variable shunting between variables in the global */
if (!MARKED((cnext = *next))) {
if (IsVarTerm(cnext) && (CELL)next == cnext) {
/* new global variable to new global variable */
if (current < H && current >= HB && next >= HB) {
#ifdef INSTRUMENT_GC
inc_var(current, current);
#endif
*next = (CELL)current;
*current = MARK_CELL((CELL)current);
return;
} else {
/* can't help here */
#ifdef INSTRUMENT_GC
inc_var(current, next);
#endif
current = next;
}
} else {
/* binding to a determinate reference */
if (next >= HB) {
*current = cnext;
total_marked--;
} else {
#ifdef INSTRUMENT_GC
inc_var(current, next);
#endif
current = next;
}
}
} else
#endif
/* what I'd do without variable shunting */
{
#ifdef INSTRUMENT_GC
inc_var(current, next);
#endif
current = next;
}
goto begin;
}
#ifdef DEBUG
else if (next < (CELL *)AtomBase)
YP_fprintf(YP_stderr, "ooops while marking %lx, %p at %p\n", (unsigned long int)ccur, current, next);
#endif
#ifdef INSTRUMENT_GC
else
inc_var(current, next);
#endif
return;
} else if (IsPairTerm(ccur)) {
#ifdef INSTRUMENT_GC
inc_vars_of_type(current,gc_list);
#endif
if (ONHEAP(next)) {
mark_variable(next);
current = next + 1;
goto begin;
} else if (ONCODE(next)) {
mark_db_fixed(RepPair(ccur));
}
return;
} else if (IsApplTerm(ccur)) {
register CELL cnext = *next;
#ifdef INSTRUMENT_GC
if (!IsExtensionFunctor((Functor)cnext))
inc_vars_of_type(current,gc_appl);
else
inc_vars_of_type(current,gc_num);
#endif
if (ONCODE(next)) {
if ((Functor)cnext == FunctorDBRef) {
DBRef tref = DBRefOfTerm(ccur);
/* make sure the reference is marked as in use */
tref->Flags |= GcFoundMask;
} else {
mark_db_fixed(next);
}
return;
}
if ( MARKED(cnext) || !ONHEAP(next) )
return;
if (next < H0) return;
if (IsExtensionFunctor((Functor)cnext)) {
switch (cnext) {
case (CELL)FunctorLongInt:
MARK(next);
total_marked += 3;
return;
case (CELL)FunctorDouble:
MARK(next);
total_marked += 2+SIZEOF_DOUBLE/SIZEOF_LONG_INT;
return;
#ifdef USE_GMP
case (CELL)FunctorBigInt:
MARK(next);
/* size is given by functor + friends */
total_marked += 2+
(sizeof(MP_INT)+
(((MP_INT *)(next+1))->_mp_alloc*sizeof(mp_limb_t)))/CellSize;
return;
#endif
default:
return;
}
}
#ifdef INSTRUMENT_GC
inc_vars_of_type(next,gc_func);
#endif
arity = ArityOfFunctor((Functor)(cnext));
MARK(next);
++total_marked;
for (i = 1; i < arity; ++i)
mark_variable(next + i);
current = next + arity;
goto begin;
}
#ifdef INSTRUMENT_GC
else if (IsAtomTerm(ccur))
inc_vars_of_type(current,gc_atom);
else
inc_vars_of_type(current, gc_int);
#endif
}
void
mark_external_reference(CELL *ptr) {
CELL reg = *ptr;
/* first, mark variables in environments */
if (IsVarTerm(reg)) {
if (ONHEAP(reg)) {
mark_variable(ptr);
total_marked--;
} else {
MARK(ptr);
}
} else if (IsApplTerm(reg)) {
CELL *next = RepAppl(reg);
if (ONHEAP(next)) {
mark_variable(ptr);
total_marked--;
} else {
MARK(ptr);
if (ONCODE(next)) {
if ((Functor)(*next) == FunctorDBRef) {
DBRef tref = DBRefOfTerm(reg);
/* make sure the reference is marked as in use */
tref->Flags |= GcFoundMask;
} else {
mark_db_fixed(next);
}
}
}
} else if (IsPairTerm(reg)) {
CELL *next = RepPair(reg);
if (ONHEAP(next)) {
mark_variable(ptr);
total_marked--;
} else {
MARK(ptr);
if (ONCODE(next)) {
mark_db_fixed(next);
}
}
} else {
/* atom or integer */
MARK(ptr);
}
}
/*
* mark all heap objects accessible from the trail (which includes the active
* general purpose registers)
*/
static void
mark_regs(tr_fr_ptr old_TR)
{
tr_fr_ptr trail_ptr;
/* first, whatever we dumped on the trail. Easier just to do
the registers separately? */
for (trail_ptr = old_TR; trail_ptr < TR; trail_ptr++)
mark_external_reference(&TrailTerm(trail_ptr));
}
#ifdef COROUTINING
static void
mark_delays(CELL *max)
{
CELL *ptr = (CELL *)GlobalBase;
for (; ptr < max; ptr++) {
mark_external_reference(ptr);
}
}
#endif
/* mark all heap objects accessible from a chain of environments */
static void
mark_environments(CELL_PTR gc_ENV, OPREG size, CELL *pvbmap)
{
CELL_PTR saved_var;
while (gc_ENV != NULL) { /* no more environments */
Int bmap = 0;
int currv = 0;
#ifdef DEBUG
if (size < 0 || size > 512)
YP_fprintf(YP_stderr,"Oops, env size %ld\n", (unsigned long int)size);
#endif
/* for each saved variable */
if (size > EnvSizeInCells) {
int tsize = size - EnvSizeInCells;
currv = sizeof(CELL)*8-tsize%(sizeof(CELL)*8);
pvbmap += tsize/(sizeof(CELL)*8);
bmap = *pvbmap;
bmap = (Int)(((CELL)bmap) << currv);
}
for (saved_var = gc_ENV - size; saved_var < gc_ENV - EnvSizeInCells; saved_var++) {
if (currv == sizeof(CELL)*8) {
pvbmap--;
bmap = *pvbmap;
currv = 0;
}
/* we may have already been here */
if (bmap < 0 && !MARKED(*saved_var)) {
#ifdef INSTRUMENT_GC
Term ccur = *saved_var;
if (IsVarTerm(ccur)) {
int len = 1;
CELL *mynext= GET_NEXT(ccur);
if (ONHEAP(mynext)) {
env_vars++;
while(ONHEAP(mynext) && IsVarTerm(*mynext)) {
CELL *prox = GET_NEXT(*mynext);
if (prox == mynext) {
chain[0]++;
break;
}
len++;
mynext = prox;
}
if (len>=15)
(chain[15])++;
else
(chain[len])++;
}
}
#endif
mark_external_reference(saved_var);
}
bmap <<= 1;
currv++;
}
/* have we met this environment before?? */
/* we use the B field in the environment to tell whether we have
been here before or not.
We do it at the end because we don't want to lose any variables
that would have been trimmed at the first environment visit.
*/
if (MARKED(gc_ENV[E_CB]))
return;
MARK(gc_ENV+E_CB);
size = EnvSize((CELL_PTR) (gc_ENV[E_CP])); /* size = EnvSize(CP) */
pvbmap = EnvBMap((CELL_PTR) (gc_ENV[E_CP]));
gc_ENV = (CELL_PTR) gc_ENV[E_E]; /* link to prev
* environment */
}
}
/*
Cleaning the trail should be quick and simple, right? Well, not
really :-(. The problem is that the trail includes a dumping ground
of the WAM registers and of extra choice-point fields, which need
to be cleaned from somewhere.
And cleaning the trail itself is not easy. The problem is that we
may not have cleaned the trail after cuts. If we naively followed
these pointers, we could have direct references to the global
stack! A solution is to verify whether we are poiting at a
legitimate trail entry. Unfortunately this requires some extra work
following choice-points.
*/
static void
mark_trail(tr_fr_ptr trail_ptr, tr_fr_ptr trail_base, CELL *gc_H, choiceptr gc_B)
{
GC_NEW_MAHASH((gc_ma_h_inner_struct *)db_vec);
while (trail_ptr > trail_base) {
register CELL trail_cell;
trail_ptr--;
trail_cell = TrailTerm(trail_ptr);
if (IsVarTerm(trail_cell)) {
CELL *hp = (CELL *)trail_cell;
/* if a variable older than the current CP has not been marked yet,
than its new binding is not accessible and we can reset it. Note
we must use gc_H to avoid trouble with dangling variables
in the heap */
if (((hp < gc_H && hp >= H0) || (hp > (CELL *)gc_B && hp < LCL0) ) && !MARKED(*hp)) {
/* reset to be a variable */
RESET_VARIABLE(hp);
discard_trail_entries++;
RESET_VARIABLE(&TrailTerm(trail_ptr));
#ifdef FROZEN_REGS
RESET_VARIABLE(&TrailVal(trail_ptr));
#endif
} else {
if (hp < (CELL *)HeapTop) {
/* I decided to allow pointers from the Heap back into the trail.
The point of doing so is to have dynamic arrays */
mark_external_reference(hp);
}
#ifdef FROZEN_REGS
mark_external_reference(&TrailVal(trail_ptr));
#endif
}
} else if (IsPairTerm(trail_cell)) {
#if DB_SEARCH_METHOD
CELL *pt0 = RepPair(trail_cell);
#ifdef FROZEN_REGS /* TRAIL */
/* avoid frozen segments */
if (
#ifdef SBA
(ADDR) pt0 >= HeapTop
#else
(ADDR) pt0 >= TrailBase
#endif
) {
trail_ptr = (tr_fr_ptr) pt0;
continue;
}
#endif /* FROZEN_REGS */
/* DB pointer */
CELL flags = Flags((CELL)pt0);
/* for the moment, if all references to the term in the stacks
are only pointers, reset the flag */
if (FlagOn(DBClMask, flags) && !FlagOn(LogUpdMask, flags)) {
if (FlagOn(DBNoVars, flags)) {
DBRef entry = (DBRef) ((CODEADDR)pt0 - (CELL) &(((DBRef) NIL)->Flags));
if (found_dbentries(entry->Contents,
entry->Contents+entry->NOfCells))
entry->Flags |= GcFoundMask;
}
}
#endif
}
#if MULTI_ASSIGNMENT_VARIABLES
else {
tr_fr_ptr *lkp;
/* This is a bit complex. The idea is that we may have several
trailings for the same mavar in the same trail segment. Essentially,
the problem arises because of !. What we want is to ignore all but
the last entry, or in this case, all but the first entry with the last
value.
Problem: we can only mark when we know it is the *last*.
Solution: we keep a list of all found entries and search in the end
*/
if (!(lkp = gc_lookup_ma_var(RepAppl(trail_cell), trail_ptr))) {
if (HEAP_PTR(trail_cell)) {
/* fool the gc into thinking this is a variable */
TrailTerm(trail_ptr) = (CELL)RepAppl(trail_cell);
mark_external_reference(&(TrailTerm(trail_ptr)));
/* reset the gc to believe the original tag */
TrailTerm(trail_ptr) = AbsAppl((CELL *)TrailTerm(trail_ptr));
#ifdef FROZEN_REGS
mark_external_reference(&TrailVal(trail_ptr));
#endif
}
trail_ptr --;
} else {
tr_fr_ptr trp = (*lkp)-1;
TrailTerm(trp) = TrailTerm(trail_ptr-1);
/* we can safely ignore this little monster */
discard_trail_entries += 2;
RESET_VARIABLE(&TrailTerm(trail_ptr));
#ifdef FROZEN_REGS
RESET_VARIABLE(&TrailVal(trail_ptr));
#endif
trail_ptr--;
RESET_VARIABLE(&TrailTerm(trail_ptr));
#ifdef FROZEN_REGS
RESET_VARIABLE(&TrailVal(trail_ptr));
#endif
}
}
#endif
}
#if MULTI_ASSIGNMENT_VARIABLES
while (live_list != NULL) {
CELL trail_cell = TrailTerm(live_list->trptr-1);
if (HEAP_PTR(trail_cell)) {
mark_external_reference(&TrailTerm(live_list->trptr-1));
}
live_list = live_list->ma_list;
}
#endif
}
/*
* mark all heap objects accessible from each choicepoint & its chain of
* environments
*/
#ifdef TABLING
#ifdef TABLING_BATCHED_SCHEDULING
#define init_substitution_pointer(GCB, SUBS_PTR, DEP_FR) \
SUBS_PTR = (CELL *) (CONS_CP(GCB) + 1)
#else /* TABLING_LOCAL_SCHEDULING */
#define init_substitution_pointer(GCB, SUBS_PTR, DEP_FR) \
SUBS_PTR = (CELL *) (CONS_CP(GCB) + 1); \
if (DepFr_leader_cp(DEP_FR) == GCB) \
SUBS_PTR += SgFr_arity(GEN_CP_SG_FR(GCB))
#endif /* TABLING_SCHEDULING */
#endif
/* #define CHECK_CHOICEPOINTS 1*/
static void
mark_choicepoints(register choiceptr gc_B, tr_fr_ptr saved_TR)
{
while (gc_B != NULL) {
op_numbers opnum;
register OPCODE op;
yamop *rtp = gc_B->cp_ap;
#ifdef SIMPLE_SHUNTING
current_B = gc_B;
#endif
HB = gc_B->cp_h;
#ifdef INSTRUMENT_GC
num_bs++;
#endif
#ifdef TABLING
/* ignore empty choicepoints */
if (rtp == NULL) {
gc_B = gc_B->cp_b;
continue;
}
#endif
op = rtp->opc;
opnum = op_from_opcode(op);
#ifdef CHECK_CHOICEPOINTS
switch (opnum) {
case _or_else:
case _or_last:
case _Nstop:
case _switch_last:
case _switch_l_list:
case _retry_c:
case _retry_userc:
case _trust_logical_pred:
case _retry_profiled:
printf("B %p (%s) with %d\n", gc_B, op_names[opnum], total_marked);
break;
#ifdef TABLING
case _table_completion:
case _table_answer_resolution:
{
PredEntry *pe = ENV_ToP(gc_B->cp_cp);
op_numbers caller_op = op_from_opcode(ENV_ToOp(gc_B->cp_cp));
/* first condition checks if this was a meta-call */
if ((caller_op != _call && caller_op != _fcall) || pe == NULL) {
printf("B %p (%s) with %d\n", gc_B, op_names[opnum], total_marked);
} else if (pe->ArityOfPE)
printf("B %p (%s for %s/%d) with %d\n", gc_B, op_names[opnum], RepAtom(NameOfFunctor(pe->FunctorOfPred))->StrOfAE, pe->ArityOfPE, total_marked);
else
printf("B %p (%s for %s/0) with %d\n", gc_B, op_names[opnum], RepAtom((Atom)(pe->FunctorOfPred))->StrOfAE, total_marked);
}
break;
#endif
default:
{
PredEntry *pe = (PredEntry *)gc_B->cp_ap->u.ld.p;
if (pe == NULL) {
printf("B %p (%s) with %d\n", gc_B, op_names[opnum], total_marked);
} else if (pe->ArityOfPE)
printf("B %p (%s for %s/%d) with %d\n", gc_B, op_names[opnum], RepAtom(NameOfFunctor(pe->FunctorOfPred))->StrOfAE, pe->ArityOfPE, total_marked);
else
printf("B %p (%s for %s/0) with %d\n", gc_B, op_names[opnum], RepAtom((Atom)(pe->FunctorOfPred))->StrOfAE, total_marked);
}
}
#endif /* CHECK_CHOICEPOINTS */
mark_trail(saved_TR, gc_B->cp_tr, gc_B->cp_h, gc_B);
saved_TR = gc_B->cp_tr;
restart_cp:
if (opnum == _or_else || opnum == _or_last) {
/* ; choice point */
mark_environments((CELL_PTR) (gc_B->cp_a1),
#ifdef YAPOR
-gc_B->cp_cp->u.ldl.s / ((OPREG)sizeof(CELL)),
EnvBMapOffset((CELL *)(gc_B->cp_cp->u.ldl.bl))
#else
-gc_B->cp_cp->u.sla.s / ((OPREG)sizeof(CELL)),
EnvBMapOffset((CELL *)(gc_B->cp_cp->u.sla.l2))
#endif
);
} else {
/* choicepoint with arguments */
register CELL_PTR saved_reg;
OPREG nargs;
if (opnum == _Nstop)
mark_environments((CELL_PTR) gc_B->cp_env,
EnvSizeInCells,
NULL);
else
#ifdef TABLING
if (opnum != _table_completion)
#endif
mark_environments((CELL_PTR) gc_B->cp_env,
EnvSize((CELL_PTR) (gc_B->cp_cp)),
EnvBMap((CELL_PTR) (gc_B->cp_cp)));
/* extended choice point */
switch (opnum) {
case _Nstop:
if (gc_B->cp_b != NULL) {
nargs = IntOfTerm(gc_B->cp_a1);
break;
} else {
/* this is the last choice point, the work is done ;-) */
return;
}
case _switch_last:
case _switch_l_list:
nargs = rtp->u.slll.s;
break;
case _retry_c:
case _retry_userc:
if (gc_B->cp_ap == RETRY_C_RECORDED_CODE
|| gc_B->cp_ap == RETRY_C_RECORDED_K_CODE
|| gc_B->cp_ap == RETRY_C_DRECORDED_CODE
|| gc_B->cp_ap == RETRY_C_RECORDEDP_CODE) {
/* we have a reference from the choice-point stack to a term */
choiceptr old_b = B;
DBRef ref;
B = gc_B;
ref = (DBRef)EXTRA_CBACK_ARG(3,1);
if (IsVarTerm((CELL)ref))
ref->Flags |= GcFoundMask;
else {
if (ONCODE((CELL)ref)) {
mark_db_fixed(RepAppl((CELL)ref));
}
}
B = old_b;
}
nargs = rtp->u.lds.s+rtp->u.lds.extra;
break;
case _trust_logical_pred:
case _retry_profiled:
rtp = NEXTOP(rtp,l);
op = rtp->opc;
opnum = op_from_opcode(op);
goto restart_cp;
#ifdef TABLING
case _table_answer_resolution:
{
CELL *answ_fr;
CELL vars;
/* fetch the solution */
init_substitution_pointer(gc_B, answ_fr, CONS_CP(gc_B)->ccp_dep_fr);
vars = *answ_fr++;
while (vars--) {
mark_external_reference(answ_fr);
answ_fr++;
}
nargs = 0;
}
break;
case _table_completion:
{
register gen_cp_ptr gcp = GEN_CP(gc_B);
#ifdef TABLING_BATCHED_SCHEDULING
nargs = gcp->gcp_sg_fr->subgoal_arity;
#else
nargs = gcp->gcp_dep_fr->subgoal_frame->subgoal_arity;
#endif
saved_reg = (CELL *)(gcp+1)+nargs;
nargs = *saved_reg++;
while (nargs--) {
mark_external_reference(saved_reg);
saved_reg++;
}
}
break;
case _table_retry_me:
case _table_trust_me:
{
register gen_cp_ptr gcp = GEN_CP(gc_B);
nargs = rtp->u.ld.s;
/* for each saved register */
for (saved_reg = (CELL *)(gcp+1);
/* assumes we can count registers in CP this
way */
saved_reg < (CELL *)(gcp+1) + nargs;
saved_reg++) {
mark_external_reference(saved_reg);
}
nargs = *saved_reg++;
while (nargs--) {
mark_external_reference(saved_reg);
saved_reg++;
}
}
break;
#endif
#ifdef DEBUG
case _retry_me:
case _trust_me:
case _profiled_retry_me:
case _profiled_trust_me:
case _retry_me0:
case _trust_me0:
case _retry_me1:
case _trust_me1:
case _retry_me2:
case _trust_me2:
case _retry_me3:
case _trust_me3:
case _retry_me4:
case _trust_me4:
case _retry_and_mark:
case _profiled_retry_and_mark:
case _retry:
case _trust_in:
case _trust:
case _retry_first:
case _trust_first_in:
case _trust_first:
case _retry_tail:
case _trust_tail_in:
case _trust_tail:
case _retry_head:
case _trust_head_in:
case _trust_head:
nargs = rtp->u.ld.s;
break;
default:
YP_fprintf(YP_stderr, "OOps in GC: Unexpected opcode: %d\n", opnum);
nargs = 0;
#else
default:
nargs = rtp->u.ld.s;
#endif
}
/* for each saved register */
for (saved_reg = &gc_B->cp_a1;
/* assumes we can count registers in CP this
way */
saved_reg < &gc_B->cp_a1 + nargs;
saved_reg++) {
mark_external_reference(saved_reg);
}
}
gc_B = gc_B->cp_b;
}
}
/*
* insert a cell which points to a heap object into relocation chain of that
* object
*/
static void
into_relocation_chain(CELL_PTR current, CELL_PTR next)
{
#ifdef TAGS_FAST_OPS
register CELL ccur = *current, cnext = *next;
if (IsVarTerm(ccur)) {
*current = ( MARKED(ccur) ? MARK_CELL(UNMARKED(cnext)) :
UNMARKED(cnext) );
*next = (MARKED(cnext) ? MBIT : 0) | RBIT | (Int) current;
} else if (IsPairTerm(ccur)) {
*current = ( MARKED(ccur) ? MARK_CELL(UNMARKED(cnext)) :
UNMARKED(cnext) );
*next = AbsPair((CELL *)
((MARKED(cnext) ? MBIT : 0) | RBIT | (Int) current));
} else if (IsApplTerm(ccur)) {
*current = ( MARKED(ccur) ? MARK_CELL(UNMARKED(cnext)) :
UNMARKED(cnext) );
*next = AbsAppl((CELL *)
((MARKED(cnext) ? MBIT : 0) | RBIT | (Int) current));
} else {
YP_fprintf(YP_stderr," OH MY GOD !!!!!!!!!!!!\n");
}
#else
CELL current_tag;
current_tag = TAG(*current);
*current = (*current & MBIT) | (*next & ~MBIT);
#if INVERT_RBIT
*next = ((*next & MBIT) | (CELL) current | current_tag) & ~RBIT;
#else
*next = (*next & MBIT) | RBIT | (CELL) current | current_tag;
#endif
#endif
}
/* insert trail cells which point to heap objects into relocation chains */
static void
sweep_trail(choiceptr gc_B, tr_fr_ptr old_TR)
{
tr_fr_ptr trail_ptr;
CELL *cp_H = gc_B->cp_h;
Int OldHeapUsed = HeapUsed;
#ifdef DEBUG
Int hp_entrs = 0, hp_erased = 0, hp_not_in_use = 0,
hp_in_use_erased = 0, code_entries = 0;
#endif
#if DB_SEARCH_METHOD
#if DEBUG
{
int i;
for (i=0; i<MAX_DB_ENTRIES; i++)
if (dbtable[i] != NULL)
fprintf(YP_stderr, "oops at entry %d: %p\n", i, dbtable[i]->addr);
}
#endif
#endif
/* first, whatever we dumped on the trail. Easier just to do
the registers separately? */
for (trail_ptr = old_TR; trail_ptr < TR; trail_ptr++) {
if (MARKED(TrailTerm(trail_ptr))) {
UNMARK(&TrailTerm(trail_ptr));
if (HEAP_PTR(TrailTerm(trail_ptr))) {
into_relocation_chain(&TrailTerm(trail_ptr), GET_NEXT(TrailTerm(trail_ptr)));
}
}
}
/* next, follows the real trail entries */
trail_ptr = old_TR;
while (trail_ptr > (tr_fr_ptr)TrailBase) {
register CELL trail_cell;
trail_ptr--;
trail_cell = TrailTerm(trail_ptr);
if (gc_B && trail_ptr < gc_B->cp_tr) {
do {
gc_B = gc_B->cp_b;
} while (gc_B && trail_ptr < gc_B->cp_tr);
cp_H = gc_B->cp_h;
}
if (IsVarTerm(trail_cell)) {
/* we need to check whether this is a honest to god trail entry */
if ((CELL *)trail_cell < cp_H && MARKED(*(CELL *)trail_cell) && (CELL *)trail_cell >= H0) {
if (HEAP_PTR(trail_cell)) {
into_relocation_chain(&TrailTerm(trail_ptr), GET_NEXT(trail_cell));
}
} else if ((CELL *)trail_cell < (CELL *)HeapTop) {
/* we may have pointers from the heap back into the cell */
UNMARK(CellPtr(trail_cell));
if (HEAP_PTR(trail_cell)) {
into_relocation_chain(CellPtr(trail_cell), GET_NEXT(*(CELL *)trail_cell));
}
} else {
/* clean the trail, avoid dangling pointers! */
if ((CELL *)trail_cell < (CELL *)gc_B && (CELL *)trail_cell >= H0) {
RESET_VARIABLE(&TrailTerm(trail_ptr));
#ifdef FROZEN_REGS
RESET_VARIABLE(&TrailVal(trail_ptr));
#endif
discard_trail_entries++;
}
}
#ifdef FROZEN_REGS
if (MARKED(TrailVal(trail_ptr))) {
UNMARK(&TrailVal(trail_ptr));
if (HEAP_PTR(TrailVal(trail_ptr))) {
into_relocation_chain(&TrailVal(trail_ptr), GET_NEXT(TrailVal(trail_ptr)));
}
}
#endif
} else if (IsPairTerm(trail_cell)) {
CELL *pt0 = RepPair(trail_cell);
CELL flags;
#ifdef FROZEN_REGS /* TRAIL */
/* process all segments */
if (
#ifdef SBA
(ADDR) pt0 >= HeapTop
#else
(ADDR) pt0 >= TrailBase
#endif
) {
continue;
}
#endif /* FROZEN_REGS */
flags = Flags((CELL)pt0);
#ifdef DEBUG
if (FlagOn(DBClMask, flags) && !FlagOn(LogUpdMask, flags)) {
hp_entrs++;
if (!FlagOn(GcFoundMask, flags)) {
hp_not_in_use++;
if (FlagOn(ErasedMask, flags)) {
hp_erased++;
}
} else {
if (FlagOn(ErasedMask, flags)) {
hp_in_use_erased++;
}
}
} else {
code_entries++;
}
#endif
if (!FlagOn(GcFoundMask, flags)) {
if (FlagOn(DBClMask, flags) && !FlagOn(LogUpdMask, flags)) {
Flags((CELL)pt0) = ResetFlag(InUseMask, flags);
if (FlagOn(ErasedMask, flags)) {
ErDBE((DBRef) ((CELL)pt0 - (CELL) &(((DBRef) NIL)->Flags)));
}
RESET_VARIABLE(trail_ptr);
discard_trail_entries++;
}
} else {
Flags((CELL)pt0) = ResetFlag(GcFoundMask, flags);
}
#if MULTI_ASSIGNMENT_VARIABLES
} else {
CELL *old_value_ptr = (CELL *)trail_ptr;
if (MARKED(trail_cell)) {
UNMARK(&TrailTerm(trail_ptr));
if (HEAP_PTR(TrailTerm(trail_ptr))) {
into_relocation_chain(&TrailTerm(trail_ptr), GET_NEXT(trail_cell));
}
}
trail_cell = old_value_ptr[-1];
#ifdef FROZEN_REGS
if (MARKED(TrailVal(trail_ptr))) {
UNMARK(&TrailVal(trail_ptr));
if (HEAP_PTR(TrailVal(trail_ptr))) {
into_relocation_chain(&TrailVal(trail_ptr), GET_NEXT(TrailTerm(trail_ptr)));
}
}
#endif
old_value_ptr--;
if (MARKED(trail_cell)) {
UNMARK(old_value_ptr);
if (HEAP_PTR(trail_cell)) {
into_relocation_chain(old_value_ptr, GET_NEXT(trail_cell));
}
}
trail_ptr = (tr_fr_ptr)old_value_ptr;
#endif
}
}
if (is_gc_verbose()) {
YP_fprintf(YP_stderr,
"[GC] Trail: discarded %d (%ld%%) cells out of %ld\n",
discard_trail_entries,
(unsigned long int)(discard_trail_entries*100/(old_TR-(tr_fr_ptr)TrailBase)),
(unsigned long int)(old_TR-(tr_fr_ptr)TrailBase));
#ifdef DEBUG
if (hp_entrs > 0)
YP_fprintf(YP_stderr,
"[GC] Trail: unmarked %ld dbentries (%ld%%) out of %ld\n",
(long int)hp_not_in_use,
(long int)(hp_not_in_use*100/hp_entrs),
(long int)hp_entrs);
if (hp_in_use_erased > 0 && hp_erased > 0)
YP_fprintf(YP_stderr,
"[GC] Trail: deleted %ld dbentries (%ld%%) out of %ld\n",
(long int)hp_erased,
(long int)(hp_erased*100/(hp_erased+hp_in_use_erased)),
(long int)(hp_erased+hp_in_use_erased));
#endif
YP_fprintf(YP_stderr,
"[GC] Heap: recovered %ld bytes (%ld%%) out of %ld\n",
(unsigned long int)(OldHeapUsed-HeapUsed),
(unsigned long int)((OldHeapUsed-HeapUsed)/(OldHeapUsed/100)),
(unsigned long int)OldHeapUsed);
}
}
/*
* insert cells of a chain of environments which point to heap objects into
* relocation chains
*/
static void
sweep_environments(CELL_PTR gc_ENV, OPREG size, CELL *pvbmap)
{
CELL_PTR saved_var;
while (gc_ENV != NULL) { /* no more environments */
Int bmap = 0;
int currv = 0;
/* for each saved variable */
if (size > EnvSizeInCells) {
int tsize = size - EnvSizeInCells;
currv = sizeof(CELL)*8-tsize%(sizeof(CELL)*8);
pvbmap += tsize/(sizeof(CELL)*8);
bmap = *pvbmap;
bmap = (Int)(((CELL)bmap) << currv);
}
for (saved_var = gc_ENV - size; saved_var < gc_ENV - EnvSizeInCells; saved_var++) {
if (currv == sizeof(CELL)*8) {
pvbmap--;
bmap = *pvbmap;
currv = 0;
}
if (bmap < 0) {
CELL env_cell = *saved_var;
if (MARKED(env_cell)) {
UNMARK(saved_var);
if (HEAP_PTR(env_cell)) {
into_relocation_chain(saved_var, GET_NEXT(env_cell));
}
}
}
bmap <<= 1;
currv++;
}
/* have we met this environment before?? */
/* we use the B field in the environment to tell whether we have
been here before or not
*/
if (!MARKED(gc_ENV[E_CB]))
return;
UNMARK(gc_ENV+E_CB);
size = EnvSize((CELL_PTR) (gc_ENV[E_CP])); /* size = EnvSize(CP) */
pvbmap = EnvBMap((CELL_PTR) (gc_ENV[E_CP]));
gc_ENV = (CELL_PTR) gc_ENV[E_E]; /* link to prev
* environment */
}
}
/*
* insert cells of each choicepoint & its chain of environments which point
* to heap objects into relocation chains
*/
static void
sweep_choicepoints(choiceptr gc_B)
{
while(gc_B != NULL) {
yamop *rtp = gc_B->cp_ap;
register OPCODE op;
op_numbers opnum;
#ifdef TABLING
/* ignore empty choicepoints */
if (rtp == NULL) {
gc_B = gc_B->cp_b;
continue;
}
#endif
op = rtp->opc;
opnum = op_from_opcode(op);
restart_cp:
/*
* YP_fprintf(YP_stderr,"sweeping cps: %x, %x, %x\n",
* *gc_B,CP_Extra(gc_B),CP_Nargs(gc_B));
*/
/* any choice point */
switch (opnum) {
case _Nstop:
/* end of the road, say bye bye! */
sweep_environments(gc_B->cp_env,
EnvSizeInCells,
NULL);
if (gc_B->cp_b != NULL) {
register CELL_PTR saved_reg;
/* for each saved register */
for (saved_reg = &gc_B->cp_a1;
saved_reg < &gc_B->cp_a1 + IntOfTerm(gc_B->cp_a1);
saved_reg++) {
CELL cp_cell = *saved_reg;
if (MARKED(cp_cell)) {
UNMARK(saved_reg);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(saved_reg, GET_NEXT(cp_cell));
}
}
}
break;
} else
return;
case _or_else:
case _or_last:
sweep_environments((CELL_PTR)(gc_B->cp_a1),
#ifdef YAPOR
-gc_B->cp_cp->u.ldl.s / ((OPREG)sizeof(CELL)),
EnvBMapOffset((CELL *)(gc_B->cp_cp->u.ldl.bl))
#else
-gc_B->cp_cp->u.sla.s / ((OPREG)sizeof(CELL)),
EnvBMapOffset((CELL *)(gc_B->cp_cp->u.sla.l2))
#endif
);
break;
case _trust_logical_pred:
case _retry_profiled:
rtp = NEXTOP(rtp,l);
op = rtp->opc;
opnum = op_from_opcode(op);
goto restart_cp;
#ifdef TABLING
case _table_answer_resolution:
{
CELL *answ_fr;
CELL vars;
sweep_environments(gc_B->cp_env,
EnvSize((CELL_PTR) (gc_B->cp_cp)),
EnvBMap((CELL_PTR) (gc_B->cp_cp)));
/* fetch the solution */
init_substitution_pointer(gc_B, answ_fr, CONS_CP(gc_B)->ccp_dep_fr);
vars = *answ_fr++;
while (vars--) {
CELL cp_cell = *answ_fr;
if (MARKED(cp_cell)) {
UNMARK(answ_fr);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(answ_fr, GET_NEXT(cp_cell));
}
}
}
}
break;
case _table_completion:
{
register gen_cp_ptr gcp = GEN_CP(gc_B);
#ifdef TABLING_BATCHED_SCHEDULING
int nargs = gcp->gcp_sg_fr->subgoal_arity;
#else
int nargs = gcp->gcp_dep_fr->subgoal_frame->subgoal_arity;
#endif
CELL *saved_reg;
saved_reg = (CELL *)(gcp+1)+nargs;
nargs = *saved_reg++;
while (nargs--) {
CELL cp_cell = *saved_reg;
if (MARKED(cp_cell)) {
UNMARK(saved_reg);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(saved_reg, GET_NEXT(cp_cell));
}
}
saved_reg++;
}
}
break;
case _table_retry_me:
case _table_trust_me:
{
register gen_cp_ptr gcp = GEN_CP(gc_B);
int nargs;
CELL *saved_reg;
sweep_environments(gc_B->cp_env,
EnvSize((CELL_PTR) (gc_B->cp_cp)),
EnvBMap((CELL_PTR) (gc_B->cp_cp)));
nargs = rtp->u.ld.s;
/* for each saved register */
for (saved_reg = (CELL *)(gcp+1);
/* assumes we can count registers in CP this
way */
saved_reg < (CELL *)(gcp+1) + nargs;
saved_reg++) {
CELL cp_cell = *saved_reg;
if (MARKED(cp_cell)) {
UNMARK(saved_reg);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(saved_reg, GET_NEXT(cp_cell));
}
}
}
saved_reg = (CELL *)(gcp+1) + nargs;
nargs = *saved_reg++;
while (nargs--) {
CELL cp_cell = *saved_reg;
if (MARKED(cp_cell)) {
UNMARK(saved_reg);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(saved_reg, GET_NEXT(cp_cell));
}
}
saved_reg++;
}
}
break;
#endif
case _retry_c:
case _retry_userc:
{
register CELL_PTR saved_reg;
/* for each extra saved register */
for (saved_reg = &(gc_B->cp_a1)+rtp->u.lds.s;
saved_reg < &(gc_B->cp_a1)+rtp->u.lds.s+rtp->u.lds.extra;
saved_reg++) {
CELL cp_cell = *saved_reg;
if (MARKED(cp_cell)) {
UNMARK(saved_reg);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(saved_reg, GET_NEXT(cp_cell));
}
}
}
}
/* continue to clean environments and arguments */
default:
{
register CELL_PTR saved_reg;
sweep_environments(gc_B->cp_env,
EnvSize((CELL_PTR) (gc_B->cp_cp)),
EnvBMap((CELL_PTR) (gc_B->cp_cp)));
/* for each saved register */
for (saved_reg = &gc_B->cp_a1;
saved_reg < &gc_B->cp_a1 + rtp->u.ld.s;
saved_reg++) {
CELL cp_cell = *saved_reg;
if (MARKED(cp_cell)) {
UNMARK(saved_reg);
if (HEAP_PTR(cp_cell)) {
into_relocation_chain(saved_reg, GET_NEXT(cp_cell));
}
}
}
}
}
/* link to prev choicepoint */
gc_B = gc_B->cp_b;
}
}
/* update a relocation chain to point all its cells to new location of object */
static void
update_relocation_chain(CELL_PTR current, CELL_PTR dest)
{
CELL_PTR next;
CELL ccur = *current;
#ifdef TAGS_FAST_OPS
while (RMARKED(ccur)) {
register CELL cnext;
next = GET_NEXT(ccur);
cnext = *next;
if (IsVarTerm(ccur)) {
ccur = *current = (MARKED_VAR(ccur) ?
ENSURE_MARKED(cnext) :
UNMARKED(cnext) );
*next = (MARKED(cnext) ? MBIT : 0) | (Int) dest;
} else if (IsPairTerm(ccur)) {
ccur = *current = (MARKED_COMP(ccur) ?
ENSURE_MARKED(cnext) :
UNMARKED(cnext) );
*next = AbsPair((CELL *)
((MARKED(cnext) ? MBIT : 0) |
(Int) dest));
} else if (IsApplTerm(ccur)) {
ccur = *current = (MARKED_COMP(ccur) ?
ENSURE_MARKED(cnext) :
UNMARKED(cnext) );
*next = AbsAppl((CELL *)
((MARKED(cnext) ? MBIT : 0) |
(Int) dest));
}
#ifdef DEBUG
else {
Abort("[GC] ATOMIC in relocation chain");
}
#endif
}
#else /* TAGS_FAST_OPS */
while (RMARKED(ccur)) {
CELL current_tag;
next = GET_NEXT(ccur);
current_tag = TAG(ccur);
ccur = *current = (ccur & MBIT) | (*next & ~MBIT);
#if INVERT_RBIT
*next = (*next & MBIT) | (CELL) dest | current_tag | RBIT;
#else
*next = (*next & MBIT) | (CELL) dest | current_tag;
#endif
}
#endif /* TAGS_FAST_OPS */
}
static inline choiceptr
update_B_H( choiceptr gc_B, CELL *current, CELL *dest, CELL *odest) {
/* also make the value of H in a choicepoint
coherent with the new global
*/
while (gc_B && current <= gc_B->cp_h) {
if (gc_B->cp_h == current) {
gc_B->cp_h = dest;
} else {
gc_B->cp_h = odest;
}
gc_B = gc_B->cp_b;
}
return(gc_B);
}
/*
* move marked objects on the heap upwards over unmarked objects, and reset
* all pointers to point to new locations
*/
static void
compact_heap(void)
{
CELL_PTR dest, current, next;
#ifdef DEBUG
Int found_marked = 0;
#endif /* DEBUG */
choiceptr gc_B = B;
int in_garbage = 0;
/*
* upward phase - scan heap from high to low, setting marked upward
* ptrs to point to what will be the new locations of the
* objects pointed to
*/
dest = (CELL_PTR) H0 + total_marked - 1;
for (current = H - 1; current >= H0; current--) {
if (MARKED(*current)) {
CELL ccell = UNMARK_CELL(*current);
if (ccell < (CELL)AtomBase && ccell > EndSpecials && IsVarTerm(ccell)
) {
/* oops, we found a blob */
int nofcells = (UNMARK_CELL(*current)-EndSpecials) / sizeof(CELL);
CELL *ptr = current - nofcells ;
CELL func = ptr[0];
if (MARKED(func)) {
#ifdef DEBUG
found_marked+=nofcells;
#endif /* DEBUG */
gc_B = update_B_H(gc_B, current, dest, dest+1);
/* this one's being used */
/* first swap the tag so that it will be seen by the next step */
{
CELL tmp = current[0];
current[0] = ptr[1];
ptr[1] = tmp;
}
if (in_garbage > 0) {
current[1] = in_garbage;
in_garbage = 0;
}
dest -= nofcells;
current = ptr;
/* process the functor next */
} else {
/* skip the term */
in_garbage += nofcells+1;
current = ptr;
continue;
}
} else{
gc_B = update_B_H(gc_B, current, dest, dest+1);
}
if (in_garbage > 0) {
current[1] = in_garbage;
in_garbage = 0;
}
#ifdef DEBUG
found_marked++;
#endif /* DEBUG */
update_relocation_chain(current, dest);
if (HEAP_PTR(*current)) {
next = GET_NEXT(*current);
if (next < current) /* push into reloc.
* chain */
into_relocation_chain(current, next);
else if (current == next) /* cell pointing to
* itself */
*current = (*current & MBIT) | (CELL) dest; /* no tag */
}
dest--;
} else {
in_garbage++;
}
}
if (in_garbage)
H0[0] = in_garbage;
#ifdef DEBUG
if (total_marked != found_marked)
YP_fprintf(YP_stderr,"[GC] Upward (%d): %ld total against %ld found\n",
gc_calls,
(unsigned long int)total_marked,
(unsigned long int)found_marked);
found_marked = 0;
#endif
/*
* downward phase - scan heap from low to high, moving marked objects
* to their new locations & setting downward pointers to pt to new
* locations
*/
dest = (CELL_PTR) H0;
for (current = H0; current < H; current++) {
CELL ccur = *current;
if (MARKED(ccur)) {
CELL uccur = UNMARK_CELL(ccur);
if (uccur < (CELL)AtomBase && uccur > EndSpecials && IsVarTerm(uccur)) {
/* oops, we found a blob */
int nofcells = (uccur-EndSpecials) / sizeof(CELL) , i;
*dest++ = current[nofcells-1];
current ++;
for (i = 0; i < nofcells-2; i++) {
*dest++ = *current++;
}
*dest++ = ccur;
#ifdef DEBUG
found_marked += nofcells;
#endif
continue;
}
#ifdef DEBUG
found_marked++;
#endif
update_relocation_chain(current, dest);
ccur = *current;
next = GET_NEXT(ccur);
if (HEAP_PTR(ccur) && /* move current cell &
* push */
next > current) { /* into relocation chain */
*dest = ccur;
into_relocation_chain(dest, next);
UNMARK(dest);
} else {
/* just move current cell */
*dest = ccur = UNMARK_CELL(ccur);
}
/* next cell, please */
dest++;
} else {
current += (ccur-1);
}
}
#ifdef DEBUG
if (total_marked != found_marked)
YP_fprintf(YP_stderr,"[GC] Downward (%d): %ld total against %ld found\n",
gc_calls,
(unsigned long int)total_marked,
(unsigned long int)found_marked);
#endif
H = dest; /* reset H */
HB = B->cp_h;
#ifdef TABLING
if (B_FZ == (choiceptr)LCL0)
H_FZ = H0;
else
H_FZ = B_FZ->cp_h;
#endif
}
/*
* mark all objects on the heap that are accessible from active registers,
* the trail, environments, and choicepoints
*/
static void
marking_phase(tr_fr_ptr old_TR, CELL *current_env, yamop *curp, CELL *max)
{
#ifdef SIMPLE_SHUNTING
current_B = B;
#endif
init_dbtable(old_TR);
/* These two must be marked first so that our trail optimisation won't lose
values */
mark_regs(old_TR); /* active registers & trail */
#ifdef COROUTINING
mark_delays(max);
#endif
/* active environments */
mark_environments(current_env, EnvSize(curp), EnvBMap((CELL *)curp));
mark_choicepoints(B, old_TR); /* choicepoints, and environs */
}
#ifdef COROUTINING
static void
sweep_delays(CELL *max)
{
CELL *ptr = (CELL *)GlobalBase;
while (ptr < max) {
if (MARKED(*ptr)) {
UNMARK(ptr);
if (HEAP_PTR(*ptr)) {
into_relocation_chain(ptr, GET_NEXT(*ptr));
}
}
ptr++;
}
}
#endif
/*
* move marked heap objects upwards over unmarked objects, and reset all
* pointers to point to new locations
*/
static void
compaction_phase(tr_fr_ptr old_TR, CELL *current_env, yamop *curp, CELL *max)
{
#ifdef COROUTINING
sweep_delays(max);
#endif
sweep_environments(current_env, EnvSize(curp), EnvBMap((CELL *)curp));
sweep_choicepoints(B);
sweep_trail(B, old_TR);
compact_heap();
}
static Int
do_gc(Int predarity, CELL *current_env, yamop *nextop)
{
Int heap_cells = H-H0;
int gc_verbose = is_gc_verbose();
tr_fr_ptr old_TR;
Int m_time, c_time, time_start, gc_time;
#ifdef COROUTINING
CELL *max = (CELL *)ReadTimedVar(DelayedVars);
#else
CELL *max = NULL;
#endif
Int effectiveness = 0;
int gc_trace = FALSE;
#ifdef INSTRUMENT_GC
{
int i;
for (i=0; i<16; i++)
chain[i]=0;
vars[gc_var] = 0;
vars[gc_ref] = 0;
vars[gc_atom] = 0;
vars[gc_int] = 0;
vars[gc_num] = 0;
vars[gc_list] = 0;
vars[gc_appl] = 0;
vars[gc_func] = 0;
vars[gc_susp] = 0;
env_vars = 0;
old_vars = new_vars = 0;
TrueHB = HB;
num_bs = 0;
}
#endif
#ifdef DEBUG
check_global();
#endif
if (GetValue(AtomGcTrace) != TermNil)
gc_trace = 1;
gc_calls++;
if (gc_trace) {
YP_fprintf(YP_stderr, "[gc]\n");
} else if (gc_verbose) {
YP_fprintf(YP_stderr, "[GC] Start of garbage collection %d:\n", gc_calls);
YP_fprintf(YP_stderr, "[GC] Global: %8ld cells (%p-%p)\n", (long int)heap_cells,H0,H);
YP_fprintf(YP_stderr, "[GC] Local:%8ld cells (%p-%p)\n", (unsigned long int)(LCL0-ASP),LCL0,ASP);
YP_fprintf(YP_stderr, "[GC] Trail:%8ld cells (%p-%p)\n",
(unsigned long int)(TR-(tr_fr_ptr)TrailBase),TrailBase,TR);
}
time_start = cputime();
total_marked = 0;
discard_trail_entries = 0;
/* get the number of active registers */
YAPEnterCriticalSection();
old_TR = TR;
push_registers(predarity, nextop);
marking_phase(old_TR, current_env, nextop, max);
m_time = cputime();
gc_time = m_time-time_start;
if (heap_cells)
effectiveness = ((heap_cells-total_marked)*100)/heap_cells;
else
effectiveness = 0;
if (gc_verbose) {
YP_fprintf(YP_stderr, "[GC] Mark: Recovered %ld cells of %ld (%ld%%) in %g sec\n",
(long int)(heap_cells-total_marked), (long int)heap_cells, (long int)effectiveness, (double)(m_time-time_start)/1000);
#ifdef INSTRUMENT_GC
{
int i;
for (i=0; i<16; i++) {
if (chain[i]) {
YP_fprintf(YP_stderr, "[GC] chain[%d]=%lu\n", i, chain[i]);
}
}
put_type_info((unsigned long int)total_marked);
YP_fprintf(YP_stderr,"[GC] %lu/%ld before and %lu/%ld after\n", old_vars, (unsigned long int)(B->cp_h-H0), new_vars, (unsigned long int)(H-B->cp_h));
YP_fprintf(YP_stderr,"[GC] %ld choicepoints\n", num_bs);
}
#endif
}
time_start = m_time;
compaction_phase(old_TR, current_env, nextop, max);
TR = old_TR;
pop_registers(predarity, nextop);
c_time = cputime();
YAPLeaveCriticalSection();
if (gc_verbose) {
YP_fprintf(YP_stderr, "[GC] Compress: took %g sec\n", (double)(c_time-time_start)/1000);
}
gc_time += (c_time-time_start);
tot_gc_time += gc_time;
tot_gc_recovered += (H-H0)-total_marked;
if (gc_verbose) {
YP_fprintf(YP_stderr, "[GC] GC %d took %g sec, total of %g sec doing GC so far.\n", gc_calls, (double)gc_time/1000, (double)tot_gc_time/1000);
YP_fprintf(YP_stderr, "[GC] Left %ld cells free in stacks.\n",
(unsigned long int)(ASP-H));
}
#ifdef DEBUG
check_global();
#endif
return(effectiveness);
}
#endif /* FIXED_STACKS */
int
is_gc_verbose(void)
{
return(GetValue(AtomGcVerbose) != TermNil);
}
Int total_gc_time(void)
{
return(tot_gc_time);
}
static Int
p_inform_gc(void)
{
Term tn = MkIntegerTerm(tot_gc_time);
Term tt = MkIntTerm(gc_calls);
Term ts = MkIntTerm((total_marked*sizeof(CELL)));
return(unify(tn, ARG2) && unify(tt, ARG1) && unify(ts, ARG3));
}
int
gc(Int predarity, CELL *current_env, yamop *nextop)
{
#ifdef FIXED_STACKS
abort_optyap("garbage collection");
#else /* FIXED_STACKS */
Int gc_margin = 128;
Term Tgc_margin;
Int effectiveness = 0;
int gc_on = FALSE;
if (GetValue(AtomGc) != TermNil)
gc_on = TRUE;
if (IsIntTerm(Tgc_margin = GetValue(AtomGcMargin)))
gc_margin = IntOfTerm(Tgc_margin);
else {
if (gc_calls < 8)
gc_margin <<= gc_calls;
else
gc_margin <<= 8;
}
if (gc_margin < 0 || gc_margin > 4000)
gc_margin = (LCL0 - H0) >> 9;
gc_margin = gc_margin << 8;
if (gc_on)
effectiveness = do_gc(predarity, current_env, nextop);
/* expand the stak if effectiveness is less than 20 % */
if (ASP - H < gc_margin || !gc_on || effectiveness < 20) {
if (ASP-H > gc_margin)
gc_margin = (ASP-H)+MinStackGap*(stack_overflows+1);
else
gc_margin = 8 * (gc_margin - (ASP - H));
gc_margin = ((gc_margin >> 16) + 1) << 16;
if (gc_margin < MinStackGap)
gc_margin = MinStackGap;
while (gc_margin >= MinStackGap && !growstack(gc_margin))
gc_margin = gc_margin/2;
#ifdef DEBUG
check_global();
#endif
return(gc_margin >= MinStackGap);
}
/*
* debug for(save_total=1; save_total<=N; ++save_total)
* plwrite(XREGS[save_total],DebugPutc,0);
*/
#endif /* FIXED_STACKS */
return ( TRUE );
}
static Int
p_gc(void)
{
#ifndef FIXED_STACKS
do_gc(0, ENV, CP);
#endif /* FIXED_STACKS */
return(TRUE);
}
void
init_gc(void)
{
InitCPred("$gc", 0, p_gc, 0);
InitCPred("$inform_gc", 3, p_inform_gc, 0);
}
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