/*

* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers

* Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.

* Copyright (c) 1998 by Silicon Graphics. All rights reserved.

* Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.

*

* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED

* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.

*

* Permission is hereby granted to use or copy this program

* for any purpose, provided the above notices are retained on all copies.

* Permission to modify the code and to distribute modified code is granted,

* provided the above notices are retained, and a notice that the code was

* modified is included with the above copyright notice.

*

*/

# include "gc_priv.h"

# include <stdio.h>

# ifndef MACOS

# include <signal.h>

# include <sys/types.h>

# endif

/*

* Separate free lists are maintained for different sized objects

* up to MAXOBJSZ.

* The call GC_allocobj(i,k) ensures that the freelist for

* kind k objects of size i points to a non-empty

* free list. It returns a pointer to the first entry on the free list.

* In a single-threaded world, GC_allocobj may be called to allocate

* an object of (small) size i as follows:

*

* opp = &(GC_objfreelist[i]);

* if (*opp == 0) GC_allocobj(i, NORMAL);

* ptr = *opp;

* *opp = obj_link(ptr);

*

* Note that this is very fast if the free list is non-empty; it should

* only involve the execution of 4 or 5 simple instructions.

* All composite objects on freelists are cleared, except for

* their first word.

*/

/*

* The allocator uses GC_allochblk to allocate large chunks of objects.

* These chunks all start on addresses which are multiples of

* HBLKSZ. Each allocated chunk has an associated header,

* which can be located quickly based on the address of the chunk.

* (See headers.c for details.)

* This makes it possible to check quickly whether an

* arbitrary address corresponds to an object administered by the

* allocator.

*/

word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */

word GC_gc_no = 0;

#ifndef SMALL_CONFIG

int GC_incremental = 0; /* By default, stop the world. */

#endif

int GC_full_freq = 19; /* Every 20th collection is a full */

/* collection, whether we need it */

/* or not. */

GC_bool GC_need_full_gc = FALSE;

/* Need full GC do to heap growth. */

word GC_used_heap_size_after_full = 0;

char * GC_copyright[] =

{"Copyright 1988,1989 Hans-J. Boehm and Alan J. Demers ",

"Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",

"Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",

"THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",

" EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",

"See source code for details." };

# include "version.h"

/* some more variables */

extern signed_word GC_mem_found; /* Number of reclaimed longwords */

/* after garbage collection */

GC_bool GC_dont_expand = 0;

word GC_free_space_divisor = 3;

extern GC_bool GC_collection_in_progress();

/* Collection is in progress, or was abandoned. */

int GC_never_stop_func GC_PROTO((void)) { return(0); }

CLOCK_TYPE GC_start_time; /* Time at which we stopped world. */

/* used only in GC_timeout_stop_func. */

int GC_n_attempts = 0; /* Number of attempts at finishing */

/* collection within TIME_LIMIT */

#ifdef SMALL_CONFIG

# define GC_timeout_stop_func GC_never_stop_func

#else

int GC_timeout_stop_func GC_PROTO((void))

{

CLOCK_TYPE current_time;

static unsigned count = 0;

unsigned long time_diff;

if ((count++ & 3) != 0) return(0);

GET_TIME(current_time);

time_diff = MS_TIME_DIFF(current_time,GC_start_time);

if (time_diff >= TIME_LIMIT) {

# ifdef PRINTSTATS

GC_printf0("Abandoning stopped marking after ");

GC_printf1("%lu msecs", (unsigned long)time_diff);

GC_printf1("(attempt %d)\n", (unsigned long) GC_n_attempts);

# endif

return(1);

}

return(0);

}

#endif /* !SMALL_CONFIG */

/* Return the minimum number of words that must be allocated between */

/* collections to amortize the collection cost. */

static word min_words_allocd()

{

# ifdef THREADS

/* We punt, for now. */

register signed_word stack_size = 10000;

# else

int dummy;

register signed_word stack_size = (ptr_t)(&dummy) - GC_stackbottom;

# endif

word total_root_size; /* includes double stack size, */

/* since the stack is expensive */

/* to scan. */

word scan_size; /* Estimate of memory to be scanned */

/* during normal GC. */

if (stack_size < 0) stack_size = -stack_size;

total_root_size = 2 * stack_size + GC_root_size;

scan_size = BYTES_TO_WORDS(GC_heapsize - GC_large_free_bytes

+ (GC_large_free_bytes >> 2)

/* use a bit more of large empty heap */

+ total_root_size);

if (GC_incremental) {

return scan_size / (2 * GC_free_space_divisor);

} else {

return scan_size / GC_free_space_divisor;

}

}

/* Return the number of words allocated, adjusted for explicit storage */

/* management, etc.. This number is used in deciding when to trigger */

/* collections. */

word GC_adj_words_allocd()

{

register signed_word result;

register signed_word expl_managed =

BYTES_TO_WORDS((long)GC_non_gc_bytes

- (long)GC_non_gc_bytes_at_gc);

/* Don't count what was explicitly freed, or newly allocated for */

/* explicit management. Note that deallocating an explicitly */

/* managed object should not alter result, assuming the client */

/* is playing by the rules. */

result = (signed_word)GC_words_allocd

- (signed_word)GC_mem_freed - expl_managed;

if (result > (signed_word)GC_words_allocd) {

result = GC_words_allocd;

/* probably client bug or unfortunate scheduling */

}

result += GC_words_finalized;

/* We count objects enqueued for finalization as though they */

/* had been reallocated this round. Finalization is user */

/* visible progress. And if we don't count this, we have */

/* stability problems for programs that finalize all objects. */

result += GC_words_wasted;

/* This doesn't reflect useful work. But if there is lots of */

/* new fragmentation, the same is probably true of the heap, */

/* and the collection will be correspondingly cheaper. */

if (result < (signed_word)(GC_words_allocd >> 3)) {

/* Always count at least 1/8 of the allocations. We don't want */

/* to collect too infrequently, since that would inhibit */

/* coalescing of free storage blocks. */

/* This also makes us partially robust against client bugs. */

return(GC_words_allocd >> 3);

} else {

return(result);

}

}

/* Clear up a few frames worth of garbage left at the top of the stack. */

/* This is used to prevent us from accidentally treating garbade left */

/* on the stack by other parts of the collector as roots. This */

/* differs from the code in misc.c, which actually tries to keep the */

/* stack clear of long-lived, client-generated garbage. */

void GC_clear_a_few_frames()

{

# define NWORDS 64

word frames[NWORDS];

register int i;

for (i = 0; i < NWORDS; i++) frames[i] = 0;

}

/* Have we allocated enough to amortize a collection? */

GC_bool GC_should_collect()

{

return(GC_adj_words_allocd() >= min_words_allocd());

}

void GC_notify_full_gc()

{

if (GC_start_call_back != (void (*)())0) {

(*GC_start_call_back)();

}

}

GC_bool GC_is_full_gc = FALSE;

/*

* Initiate a garbage collection if appropriate.

* Choose judiciously

* between partial, full, and stop-world collections.

* Assumes lock held, signals disabled.

*/

void GC_maybe_gc()

{

static int n_partial_gcs = 0;

if (GC_should_collect()) {

if (!GC_incremental) {

GC_notify_full_gc();

GC_gcollect_inner();

n_partial_gcs = 0;

return;

} else if (GC_need_full_gc || n_partial_gcs >= GC_full_freq) {

# ifdef PRINTSTATS

GC_printf2(

"***>Full mark for collection %lu after %ld allocd bytes\n",

(unsigned long) GC_gc_no+1,

(long)WORDS_TO_BYTES(GC_words_allocd));

# endif

GC_promote_black_lists();

(void)GC_reclaim_all((GC_stop_func)0, TRUE);

GC_clear_marks();

n_partial_gcs = 0;

GC_notify_full_gc();

GC_is_full_gc = TRUE;

} else {

n_partial_gcs++;

}

/* We try to mark with the world stopped. */

/* If we run out of time, this turns into */

/* incremental marking. */

GET_TIME(GC_start_time);

if (GC_stopped_mark(GC_timeout_stop_func)) {

# ifdef SAVE_CALL_CHAIN

GC_save_callers(GC_last_stack);

# endif

GC_finish_collection();

} else {

if (!GC_is_full_gc) {

/* Count this as the first attempt */

GC_n_attempts++;

}

}

}

}

/*

* Stop the world garbage collection. Assumes lock held, signals disabled.

* If stop_func is not GC_never_stop_func, then abort if stop_func returns TRUE.

*/

GC_bool GC_try_to_collect_inner(stop_func)

GC_stop_func stop_func;

{

if (GC_incremental && GC_collection_in_progress()) {

# ifdef PRINTSTATS

GC_printf0(

"GC_try_to_collect_inner: finishing collection in progress\n");

# endif /* PRINTSTATS */

/* Just finish collection already in progress. */

while(GC_collection_in_progress()) {

if (stop_func()) return(FALSE);

GC_collect_a_little_inner(1);

}

}

# ifdef PRINTSTATS

GC_printf2(

"Initiating full world-stop collection %lu after %ld allocd bytes\n",

(unsigned long) GC_gc_no+1,

(long)WORDS_TO_BYTES(GC_words_allocd));

# endif

GC_promote_black_lists();

/* Make sure all blocks have been reclaimed, so sweep routines */

/* don't see cleared mark bits. */

/* If we're guaranteed to finish, then this is unnecessary. */

if (stop_func != GC_never_stop_func

&& !GC_reclaim_all(stop_func, FALSE)) {

/* Aborted. So far everything is still consistent. */

return(FALSE);

}

GC_invalidate_mark_state(); /* Flush mark stack. */

GC_clear_marks();

# ifdef SAVE_CALL_CHAIN

GC_save_callers(GC_last_stack);

# endif

GC_is_full_gc = TRUE;

if (!GC_stopped_mark(stop_func)) {

if (!GC_incremental) {

/* We're partially done and have no way to complete or use */

/* current work. Reestablish invariants as cheaply as */

/* possible. */

GC_invalidate_mark_state();

GC_unpromote_black_lists();

} /* else we claim the world is already still consistent. We'll */

/* finish incrementally. */

return(FALSE);

}

GC_finish_collection();

return(TRUE);

}

/*

* Perform n units of garbage collection work. A unit is intended to touch

* roughly GC_RATE pages. Every once in a while, we do more than that.

* This needa to be a fairly large number with our current incremental

* GC strategy, since otherwise we allocate too much during GC, and the

* cleanup gets expensive.

*/

# define GC_RATE 10

# define MAX_PRIOR_ATTEMPTS 1

/* Maximum number of prior attempts at world stop marking */

/* A value of 1 means that we finish the seconf time, no matter */

/* how long it takes. Doesn't count the initial root scan */

/* for a full GC. */

int GC_deficit = 0; /* The number of extra calls to GC_mark_some */

/* that we have made. */

void GC_collect_a_little_inner(n)

int n;

{

register int i;

if (GC_incremental && GC_collection_in_progress()) {

for (i = GC_deficit; i < GC_RATE*n; i++) {

if (GC_mark_some((ptr_t)0)) {

/* Need to finish a collection */

# ifdef SAVE_CALL_CHAIN

GC_save_callers(GC_last_stack);

# endif

if (GC_n_attempts < MAX_PRIOR_ATTEMPTS) {

GET_TIME(GC_start_time);

if (!GC_stopped_mark(GC_timeout_stop_func)) {

GC_n_attempts++;

break;

}

} else {

(void)GC_stopped_mark(GC_never_stop_func);

}

GC_finish_collection();

break;

}

}

if (GC_deficit > 0) GC_deficit -= GC_RATE*n;

if (GC_deficit < 0) GC_deficit = 0;

} else {

GC_maybe_gc();

}

}

int GC_collect_a_little GC_PROTO(())

{

int result;

DCL_LOCK_STATE;

DISABLE_SIGNALS();

LOCK();

GC_collect_a_little_inner(1);

result = (int)GC_collection_in_progress();

UNLOCK();

ENABLE_SIGNALS();

return(result);

}

/*

* Assumes lock is held, signals are disabled.

* We stop the world.

* If stop_func() ever returns TRUE, we may fail and return FALSE.

* Increment GC_gc_no if we succeed.

*/

GC_bool GC_stopped_mark(stop_func)

GC_stop_func stop_func;

{

register int i;

int dummy;

# ifdef PRINTSTATS

CLOCK_TYPE start_time, current_time;

# endif

STOP_WORLD();

# ifdef PRINTSTATS

GET_TIME(start_time);

GC_printf1("--> Marking for collection %lu ",

(unsigned long) GC_gc_no + 1);

GC_printf2("after %lu allocd bytes + %lu wasted bytes\n",

(unsigned long) WORDS_TO_BYTES(GC_words_allocd),

(unsigned long) WORDS_TO_BYTES(GC_words_wasted));

# endif

/* Mark from all roots. */

/* Minimize junk left in my registers and on the stack */

GC_clear_a_few_frames();

GC_noop(0,0,0,0,0,0);

GC_initiate_gc();

for(i = 0;;i++) {

if ((*stop_func)()) {

# ifdef PRINTSTATS

GC_printf0("Abandoned stopped marking after ");

GC_printf1("%lu iterations\n",

(unsigned long)i);

# endif

GC_deficit = i; /* Give the mutator a chance. */

START_WORLD();

return(FALSE);

}

if (GC_mark_some((ptr_t)(&dummy))) break;

}

GC_gc_no++;

# ifdef PRINTSTATS

GC_printf2("Collection %lu reclaimed %ld bytes",

(unsigned long) GC_gc_no - 1,

(long)WORDS_TO_BYTES(GC_mem_found));

GC_printf1(" ---> heapsize = %lu bytes\n",

(unsigned long) GC_heapsize);

/* Printf arguments may be pushed in funny places. Clear the */

/* space. */

GC_printf0("");

# endif

/* Check all debugged objects for consistency */

if (GC_debugging_started) {

(*GC_check_heap)();

}

# ifdef PRINTTIMES

GET_TIME(current_time);

GC_printf1("World-stopped marking took %lu msecs\n",

MS_TIME_DIFF(current_time,start_time));

# endif

START_WORLD();

return(TRUE);

}

/* Finish up a collection. Assumes lock is held, signals are disabled, */

/* but the world is otherwise running. */

void GC_finish_collection()

{

# ifdef PRINTTIMES

CLOCK_TYPE start_time;

CLOCK_TYPE finalize_time;

CLOCK_TYPE done_time;

GET_TIME(start_time);

finalize_time = start_time;

# endif

# ifdef GATHERSTATS

GC_mem_found = 0;

# endif

if (GC_find_leak) {

/* Mark all objects on the free list. All objects should be */

/* marked when we're done. */

{

register word size; /* current object size */

register ptr_t p; /* pointer to current object */

register struct hblk * h; /* pointer to block containing *p */

register hdr * hhdr;

register int word_no; /* "index" of *p in *q */

int kind;

for (kind = 0; kind < GC_n_kinds; kind++) {

for (size = 1; size <= MAXOBJSZ; size++) {

for (p= GC_obj_kinds[kind].ok_freelist[size];

p != 0; p=obj_link(p)){

h = HBLKPTR(p);

hhdr = HDR(h);

word_no = (((word *)p) - ((word *)h));

set_mark_bit_from_hdr(hhdr, word_no);

}

}

}

}

GC_start_reclaim(TRUE);

/* The above just checks; it doesn't really reclaim anything. */

}

GC_finalize();

# ifdef STUBBORN_ALLOC

GC_clean_changing_list();

# endif

# ifdef PRINTTIMES

GET_TIME(finalize_time);

# endif

/* Clear free list mark bits, in case they got accidentally marked */

/* Note: HBLKPTR(p) == pointer to head of block containing *p */

/* (or GC_find_leak is set and they were intentionally marked.) */

/* Also subtract memory remaining from GC_mem_found count. */

/* Note that composite objects on free list are cleared. */

/* Thus accidentally marking a free list is not a problem; only */

/* objects on the list itself will be marked, and that's fixed here. */

{

register word size; /* current object size */

register ptr_t p; /* pointer to current object */

register struct hblk * h; /* pointer to block containing *p */

register hdr * hhdr;

register int word_no; /* "index" of *p in *q */

int kind;

for (kind = 0; kind < GC_n_kinds; kind++) {

for (size = 1; size <= MAXOBJSZ; size++) {

for (p= GC_obj_kinds[kind].ok_freelist[size];

p != 0; p=obj_link(p)){

h = HBLKPTR(p);

hhdr = HDR(h);

word_no = (((word *)p) - ((word *)h));

clear_mark_bit_from_hdr(hhdr, word_no);

# ifdef GATHERSTATS

GC_mem_found -= size;

# endif

}

}

}

}

# ifdef PRINTSTATS

GC_printf1("Bytes recovered before sweep - f.l. count = %ld\n",

(long)WORDS_TO_BYTES(GC_mem_found));

# endif

/* Reconstruct free lists to contain everything not marked */

GC_start_reclaim(FALSE);

if (GC_is_full_gc) {

GC_used_heap_size_after_full = USED_HEAP_SIZE;

GC_need_full_gc = FALSE;

} else {

GC_need_full_gc =

BYTES_TO_WORDS(USED_HEAP_SIZE - GC_used_heap_size_after_full)

> min_words_allocd();

}

# ifdef PRINTSTATS

GC_printf2(

"Immediately reclaimed %ld bytes in heap of size %lu bytes",

(long)WORDS_TO_BYTES(GC_mem_found),

(unsigned long)GC_heapsize);

# ifdef USE_MUNMAP

GC_printf1("(%lu unmapped)", GC_unmapped_bytes);

# endif

GC_printf2(

"\n%lu (atomic) + %lu (composite) collectable bytes in use\n",

(unsigned long)WORDS_TO_BYTES(GC_atomic_in_use),

(unsigned long)WORDS_TO_BYTES(GC_composite_in_use));

# endif

GC_n_attempts = 0;

GC_is_full_gc = FALSE;

/* Reset or increment counters for next cycle */

GC_words_allocd_before_gc += GC_words_allocd;

GC_non_gc_bytes_at_gc = GC_non_gc_bytes;

GC_words_allocd = 0;

GC_words_wasted = 0;

GC_mem_freed = 0;

# ifdef USE_MUNMAP

GC_unmap_old();

# endif

# ifdef PRINTTIMES

GET_TIME(done_time);

GC_printf2("Finalize + initiate sweep took %lu + %lu msecs\n",

MS_TIME_DIFF(finalize_time,start_time),

MS_TIME_DIFF(done_time,finalize_time));

# endif

}

/* Externally callable routine to invoke full, stop-world collection */

# if defined(__STDC__) || defined(__cplusplus)

int GC_try_to_collect(GC_stop_func stop_func)

# else

int GC_try_to_collect(stop_func)

GC_stop_func stop_func;

# endif

{

int result;

DCL_LOCK_STATE;

GC_INVOKE_FINALIZERS();

DISABLE_SIGNALS();

LOCK();

ENTER_GC();

if (!GC_is_initialized) GC_init_inner();

/* Minimize junk left in my registers */

GC_noop(0,0,0,0,0,0);

result = (int)GC_try_to_collect_inner(stop_func);

EXIT_GC();

UNLOCK();

ENABLE_SIGNALS();

if(result) GC_INVOKE_FINALIZERS();

return(result);

}

void GC_gcollect GC_PROTO(())

{

GC_notify_full_gc();

(void)GC_try_to_collect(GC_never_stop_func);

}

word GC_n_heap_sects = 0; /* Number of sections currently in heap. */

/*

* Use the chunk of memory starting at p of size bytes as part of the heap.

* Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE.

*/

void GC_add_to_heap(p, bytes)

struct hblk *p;

word bytes;

{

word words;

hdr * phdr;

if (GC_n_heap_sects >= MAX_HEAP_SECTS) {

ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS");

}

phdr = GC_install_header(p);

if (0 == phdr) {

/* This is extremely unlikely. Can't add it. This will */

/* almost certainly result in a 0 return from the allocator, */

/* which is entirely appropriate. */

return;

}

GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p;

GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes;

GC_n_heap_sects++;

words = BYTES_TO_WORDS(bytes - HDR_BYTES);

phdr -> hb_sz = words;

phdr -> hb_map = (char *)1; /* A value != GC_invalid_map */

phdr -> hb_flags = 0;

GC_freehblk(p);

GC_heapsize += bytes;

if ((ptr_t)p <= GC_least_plausible_heap_addr

|| GC_least_plausible_heap_addr == 0) {

GC_least_plausible_heap_addr = (ptr_t)p - sizeof(word);

/* Making it a little smaller than necessary prevents */

/* us from getting a false hit from the variable */

/* itself. There's some unintentional reflection */

/* here. */

}

if ((ptr_t)p + bytes >= GC_greatest_plausible_heap_addr) {

GC_greatest_plausible_heap_addr = (ptr_t)p + bytes;

}

}

# if !defined(NO_DEBUGGING)

void GC_print_heap_sects()

{

register unsigned i;

GC_printf1("Total heap size: %lu\n", (unsigned long) GC_heapsize);

for (i = 0; i < GC_n_heap_sects; i++) {

unsigned long start = (unsigned long) GC_heap_sects[i].hs_start;

unsigned long len = (unsigned long) GC_heap_sects[i].hs_bytes;

struct hblk *h;

unsigned nbl = 0;

GC_printf3("Section %ld from 0x%lx to 0x%lx ", (unsigned long)i,

start, (unsigned long)(start + len));

for (h = (struct hblk *)start; h < (struct hblk *)(start + len); h++) {

if (GC_is_black_listed(h, HBLKSIZE)) nbl++;

}

GC_printf2("%lu/%lu blacklisted\n", (unsigned long)nbl,

(unsigned long)(len/HBLKSIZE));

}

}

# endif

ptr_t GC_least_plausible_heap_addr = (ptr_t)ONES;

ptr_t GC_greatest_plausible_heap_addr = 0;

ptr_t GC_max(x,y)

ptr_t x, y;

{

return(x > y? x : y);

}

ptr_t GC_min(x,y)

ptr_t x, y;

{

return(x < y? x : y);

}

# if defined(__STDC__) || defined(__cplusplus)

void GC_set_max_heap_size(GC_word n)

# else

void GC_set_max_heap_size(n)

GC_word n;

# endif

{

GC_max_heapsize = n;

}

GC_word GC_max_retries = 0;

/*

* this explicitly increases the size of the heap. It is used

* internally, but may also be invoked from GC_expand_hp by the user.

* The argument is in units of HBLKSIZE.

* Tiny values of n are rounded up.

* Returns FALSE on failure.

*/

GC_bool GC_expand_hp_inner(n)

word n;

{

word bytes;

struct hblk * space;

word expansion_slop; /* Number of bytes by which we expect the */

/* heap to expand soon. */

if (n < MINHINCR) n = MINHINCR;

bytes = n * HBLKSIZE;

/* Make sure bytes is a multiple of GC_page_size */

{

word mask = GC_page_size - 1;

bytes += mask;

bytes &= ~mask;

}

if (GC_max_heapsize != 0 && GC_heapsize + bytes > GC_max_heapsize) {

/* Exceeded self-imposed limit */

return(FALSE);

}

space = GET_MEM(bytes);

if( space == 0 ) {

return(FALSE);

}

# ifdef PRINTSTATS

GC_printf2("Increasing heap size by %lu after %lu allocated bytes\n",

(unsigned long)bytes,

(unsigned long)WORDS_TO_BYTES(GC_words_allocd));

# ifdef UNDEFINED

GC_printf1("Root size = %lu\n", GC_root_size);

GC_print_block_list(); GC_print_hblkfreelist();

GC_printf0("\n");

# endif

# endif

expansion_slop = 8 * WORDS_TO_BYTES(min_words_allocd());

if (5 * HBLKSIZE * MAXHINCR > expansion_slop) {

expansion_slop = 5 * HBLKSIZE * MAXHINCR;

}

if (GC_last_heap_addr == 0 && !((word)space & SIGNB)

|| GC_last_heap_addr != 0 && GC_last_heap_addr < (ptr_t)space) {

/* Assume the heap is growing up */

GC_greatest_plausible_heap_addr =

GC_max(GC_greatest_plausible_heap_addr,

(ptr_t)space + bytes + expansion_slop);

} else {

/* Heap is growing down */

GC_least_plausible_heap_addr =

GC_min(GC_least_plausible_heap_addr,

(ptr_t)space - expansion_slop);

}

GC_prev_heap_addr = GC_last_heap_addr;

GC_last_heap_addr = (ptr_t)space;

GC_add_to_heap(space, bytes);

return(TRUE);

}

/* Really returns a bool, but it's externally visible, so that's clumsy. */

/* Arguments is in bytes. */

# if defined(__STDC__) || defined(__cplusplus)

int GC_expand_hp(size_t bytes)

# else

int GC_expand_hp(bytes)

size_t bytes;

# endif

{

int result;

DCL_LOCK_STATE;

DISABLE_SIGNALS();

LOCK();

if (!GC_is_initialized) GC_init_inner();

result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes));

if (result) GC_requested_heapsize += bytes;

UNLOCK();

ENABLE_SIGNALS();

return(result);

}

unsigned GC_fail_count = 0;

/* How many consecutive GC/expansion failures? */

/* Reset by GC_allochblk. */

GC_bool GC_collect_or_expand(needed_blocks, ignore_off_page)

word needed_blocks;

GC_bool ignore_off_page;

{

if (!GC_incremental && !GC_dont_gc &&

(GC_dont_expand && GC_words_allocd > 0 || GC_should_collect())) {

GC_notify_full_gc();

GC_gcollect_inner();

} else {

word blocks_to_get = GC_heapsize/(HBLKSIZE*GC_free_space_divisor)

+ needed_blocks;

if (blocks_to_get > MAXHINCR) {

word slop;

if (ignore_off_page) {

slop = 4;

} else {

slop = 2*divHBLKSZ(BL_LIMIT);

if (slop > needed_blocks) slop = needed_blocks;

}

if (needed_blocks + slop > MAXHINCR) {

blocks_to_get = needed_blocks + slop;

} else {

blocks_to_get = MAXHINCR;

}

}

if (!GC_expand_hp_inner(blocks_to_get)

&& !GC_expand_hp_inner(needed_blocks)) {

if (GC_fail_count++ < GC_max_retries) {

WARN("Out of Memory! Trying to continue ...\n", 0);

GC_notify_full_gc();

GC_gcollect_inner();

} else {

WARN("Out of Memory! Returning NIL!\n", 0);

return(FALSE);

}

} else {

# ifdef PRINTSTATS

if (GC_fail_count) {

GC_printf0("Memory available again ...\n");

}

# endif

}

}

return(TRUE);

}

/*

* Make sure the object free list for sz is not empty.

* Return a pointer to the first object on the free list.

* The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER.

* Assumes we hold the allocator lock and signals are disabled.

*

*/

ptr_t GC_allocobj(sz, kind)

word sz;

int kind;

{

register ptr_t * flh = &(GC_obj_kinds[kind].ok_freelist[sz]);

if (sz == 0) return(0);

while (*flh == 0) {

ENTER_GC();

/* Do our share of marking work */

if(GC_incremental && !GC_dont_gc) GC_collect_a_little_inner(1);

/* Sweep blocks for objects of this size */

GC_continue_reclaim(sz, kind);

EXIT_GC();

if (*flh == 0) {

GC_new_hblk(sz, kind);

}

if (*flh == 0) {

ENTER_GC();

if (!GC_collect_or_expand((word)1,FALSE)) {

EXIT_GC();

return(0);

}

EXIT_GC();

}

}

return(*flh);

}