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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1993 by Xerox Corporation. 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 copy this garbage collector for any purpose,
* provided the above notices are retained on all copies.
*/
#define DEBUG /* Some run-time consistency checks */
#undef DEBUG
#define VERBOSE
#undef VERBOSE
#include <stdio.h>
#include <signal.h>
#define I_HIDE_POINTERS /* To make GC_call_with_alloc_lock visible */
#include "gc_private.h"
# ifdef THREADS
# ifdef PCR
# include "pcr/il/PCR_IL.h"
struct PCR_Th_MLRep GC_allocate_ml;
# else
--> declare allocator lock here
# endif
# endif
struct _GC_arrays GC_arrays = { 0 };
/* Initialize GC_obj_kinds properly and standard free lists properly. */
/* This must be done statically since they may be accessed before */
/* GC_init is called. */
struct obj_kind GC_obj_kinds[MAXOBJKINDS] = {
/* PTRFREE */ { &GC_aobjfreelist[0], &GC_areclaim_list[0],
GC_no_mark_proc, FALSE },
/* NORMAL */ { &GC_objfreelist[0], &GC_reclaim_list[0],
GC_normal_mark_proc, TRUE },
/* UNCOLLECTABLE */
{ &GC_uobjfreelist[0], &GC_ureclaim_list[0],
GC_normal_mark_proc, TRUE },
# ifdef STUBBORN_ALLOC
/*STUBBORN*/ { &GC_sobjfreelist[0], &GC_sreclaim_list[0],
GC_normal_mark_proc, TRUE },
# endif
};
# ifdef STUBBORN_ALLOC
int GC_n_kinds = 4;
# else
int GC_n_kinds = 3;
# endif
bool GC_debugging_started = FALSE;
/* defined here so we don't have to load debug_malloc.o */
void (*GC_check_heap)() = (void (*)())0;
ptr_t GC_stackbottom = 0;
word GC_hincr;
bool GC_dont_gc = 0;
bool GC_quiet = 0;
extern signed_word GC_mem_found;
# ifdef MERGE_SIZES
/* Set things up so that GC_size_map[i] >= words(i), */
/* but not too much bigger */
/* and so that size_map contains relatively few distinct entries */
/* This is stolen from Russ Atkinson's Cedar quantization */
/* alogrithm (but we precompute it). */
void GC_init_size_map()
{
register unsigned i;
register unsigned sz_rounded_up = 0;
/* Map size 0 to 1. This avoids problems at lower levels. */
GC_size_map[0] = 1;
/* One word objects don't have to be 2 word aligned. */
for (i = 1; i < sizeof(word); i++) {
GC_size_map[i] = 1;
}
GC_size_map[sizeof(word)] = ROUNDED_UP_WORDS(sizeof(word));
for (i = sizeof(word) + 1; i <= 8 * sizeof(word); i++) {
# ifdef ALIGN_DOUBLE
GC_size_map[i] = (ROUNDED_UP_WORDS(i) + 1) & (~1);
# else
GC_size_map[i] = ROUNDED_UP_WORDS(i);
# endif
}
for (i = 8*sizeof(word)+1; i <= WORDS_TO_BYTES(MAXOBJSZ); i++) {
if (sz_rounded_up < ROUNDED_UP_WORDS(i)) {
register int size = ROUNDED_UP_WORDS(i);
register unsigned m = 0;
while (size > 7) {
m += 1;
size += 1;
size >>= 1;
}
sz_rounded_up = size << m;
if (sz_rounded_up > MAXOBJSZ) {
sz_rounded_up = MAXOBJSZ;
}
}
GC_size_map[i] = sz_rounded_up;
}
}
# endif
/*
* The following is a gross hack to deal with a problem that can occur
* on machines that are sloppy about stack frame sizes, notably SPARC.
* Bogus pointers may be written to the stack and not cleared for
* a LONG time, because they always fall into holes in stack frames
* that are not written. We partially address this by randomly clearing
* sections of the stack whenever we get control.
*/
word GC_stack_last_cleared = 0; /* GC_no when we last did this */
# define CLEAR_SIZE 213
# define CLEAR_THRESHOLD 10000
# define DEGRADE_RATE 50
ptr_t GC_min_sp; /* Coolest stack pointer value from which we've */
/* already cleared the stack. */
# ifdef STACK_GROWS_DOWN
# define COOLER_THAN >
# define HOTTER_THAN <
# define MAKE_COOLER(x,y) if ((word)(x)+(y) > (word)(x)) {(x) += (y);} \
else {(x) = (ptr_t)ONES;}
# define MAKE_HOTTER(x,y) (x) -= (y)
# else
# define COOLER_THAN <
# define HOTTER_THAN >
# define MAKE_COOLER(x,y) if ((word)(x)-(y) < (word)(x)) {(x) -= (y);} else {(x) = 0;}
# define MAKE_HOTTER(x,y) (x) += (y)
# endif
ptr_t GC_high_water;
/* "hottest" stack pointer value we have seen */
/* recently. Degrades over time. */
/*ARGSUSED*/
void GC_clear_stack_inner(d)
word *d;
{
word dummy[CLEAR_SIZE];
bzero((char *)dummy, (int)(CLEAR_SIZE*sizeof(word)));
# ifdef THREADS
GC_noop(dummy);
# else
if ((ptr_t)(dummy) COOLER_THAN GC_min_sp) {
GC_clear_stack_inner(dummy);
}
# endif
}
void GC_clear_stack()
{
word dummy;
# ifdef THREADS
GC_clear_stack_inner(&dummy);
# else
if (GC_gc_no > GC_stack_last_cleared) {
/* Start things over, so we clear the entire stack again */
if (GC_stack_last_cleared == 0) GC_high_water = GC_stackbottom;
GC_min_sp = GC_high_water;
GC_stack_last_cleared = GC_gc_no;
}
/* Adjust GC_high_water */
MAKE_COOLER(GC_high_water, WORDS_TO_BYTES(DEGRADE_RATE));
if ((word)(&dummy) HOTTER_THAN (word)GC_high_water) {
GC_high_water = (ptr_t)(&dummy);
}
if ((word)(&dummy) COOLER_THAN (word)GC_min_sp) {
GC_clear_stack_inner(&dummy);
GC_min_sp = (ptr_t)(&dummy);
}
# endif
}
/* Return a pointer to the base address of p, given a pointer to a */
/* an address within an object. Return 0 o.w. */
# ifdef __STDC__
extern_ptr_t GC_base(extern_ptr_t p)
# else
extern_ptr_t GC_base(p)
extern_ptr_t p;
# endif
{
register word r;
register struct hblk *h;
register hdr *candidate_hdr;
r = (word)p;
h = HBLKPTR(r);
candidate_hdr = HDR(r);
if (candidate_hdr == 0) return(0);
/* If it's a pointer to the middle of a large object, move it */
/* to the beginning. */
while (IS_FORWARDING_ADDR_OR_NIL(candidate_hdr)) {
h = h - (int)candidate_hdr;
r = (word)h + HDR_BYTES;
candidate_hdr = HDR(h);
}
if (candidate_hdr -> hb_map == GC_invalid_map) return(0);
/* Make sure r points to the beginning of the object */
r &= ~(WORDS_TO_BYTES(1) - 1);
{
register int offset =
(word *)r - (word *)(HBLKPTR(r)) - HDR_WORDS;
register signed_word sz = candidate_hdr -> hb_sz;
register int correction;
correction = offset % sz;
r -= (WORDS_TO_BYTES(correction));
if (((word *)r + sz) > (word *)(h + 1)
&& sz <= BYTES_TO_WORDS(HBLKSIZE) - HDR_WORDS) {
return(0);
}
}
return((extern_ptr_t)r);
}
/* Return the size of an object, given a pointer to its base. */
/* (For small obects this also happens to work from interior pointers, */
/* but that shouldn't be relied upon.) */
# ifdef __STDC__
size_t GC_size(extern_ptr_t p)
# else
size_t GC_size(p)
extern_ptr_t p;
# endif
{
register int sz;
register hdr * hhdr = HDR(p);
sz = WORDS_TO_BYTES(hhdr -> hb_sz);
if (sz < 0) {
return(-sz);
} else {
return(sz);
}
}
bool GC_is_initialized = FALSE;
void GC_init()
{
DCL_LOCK_STATE;
DISABLE_SIGNALS();
LOCK();
GC_init_inner();
UNLOCK();
ENABLE_SIGNALS();
}
void GC_init_inner()
{
word dummy;
if (GC_is_initialized) return;
GC_is_initialized = TRUE;
# ifndef THREADS
if (GC_stackbottom == 0) {
GC_stackbottom = GC_get_stack_base();
}
# endif
if (sizeof (ptr_t) != sizeof(word)) {
GC_err_printf0("sizeof (ptr_t) != sizeof(word)\n");
ABORT("sizeof (ptr_t) != sizeof(word)\n");
}
if (sizeof (signed_word) != sizeof(word)) {
GC_err_printf0("sizeof (signed_word) != sizeof(word)\n");
ABORT("sizeof (signed_word) != sizeof(word)\n");
}
if (sizeof (struct hblk) != HBLKSIZE) {
GC_err_printf0("sizeof (struct hblk) != HBLKSIZE\n");
ABORT("sizeof (struct hblk) != HBLKSIZE\n");
}
# ifndef THREADS
# if defined(STACK_GROWS_UP) && defined(STACK_GROWS_DOWN)
GC_err_printf0(
"Only one of STACK_GROWS_UP and STACK_GROWS_DOWN should be defd\n");
ABORT("stack direction 1\n");
# endif
# if !defined(STACK_GROWS_UP) && !defined(STACK_GROWS_DOWN)
GC_err_printf0(
"One of STACK_GROWS_UP and STACK_GROWS_DOWN should be defd\n");
ABORT("stack direction 2\n");
# endif
# ifdef STACK_GROWS_DOWN
if ((word)(&dummy) > (word)GC_stackbottom) {
GC_err_printf0(
"STACK_GROWS_DOWN is defd, but stack appears to grow up\n");
GC_err_printf2("sp = 0x%lx, GC_stackbottom = 0x%lx\n",
(unsigned long) (&dummy),
(unsigned long) GC_stackbottom);
ABORT("stack direction 3\n");
}
# else
if ((word)(&dummy) < (word)GC_stackbottom) {
GC_err_printf0(
"STACK_GROWS_UP is defd, but stack appears to grow down\n");
GC_err_printf2("sp = 0x%lx, GC_stackbottom = 0x%lx\n",
(unsigned long) (&dummy),
(unsigned long) GC_stackbottom);
ABORT("stack direction 4");
}
# endif
# endif
# if !defined(_AUX_SOURCE) || defined(__GNUC__)
if ((word)(-1) < (word)0) {
GC_err_printf0("The type word should be an unsigned integer type\n");
GC_err_printf0("It appears to be signed\n");
ABORT("word");
}
# endif
if ((signed_word)(-1) >= (signed_word)0) {
GC_err_printf0(
"The type signed_word should be a signed integer type\n");
GC_err_printf0("It appears to be unsigned\n");
ABORT("signed_word");
}
GC_hincr = HINCR;
GC_init_headers();
GC_bl_init();
GC_mark_init();
if (!GC_expand_hp_inner(GC_hincr)) {
GC_err_printf0("Can't start up: not enough memory\n");
EXIT();
}
/* Preallocate large object map. It's otherwise inconvenient to */
/* deal with failure. */
if (!GC_add_map_entry((word)0)) {
GC_err_printf0("Can't start up: not enough memory\n");
EXIT();
}
GC_register_displacement_inner(0L);
# ifdef MERGE_SIZES
GC_init_size_map();
# endif
/* Add initial guess of root sets */
GC_register_data_segments();
# ifdef PCR
PCR_IL_Lock(PCR_Bool_false, PCR_allSigsBlocked, PCR_waitForever);
PCR_IL_Unlock();
GC_pcr_install();
# endif
/* Get black list set up */
GC_gcollect_inner();
# ifdef STUBBORN_ALLOC
GC_stubborn_init();
# endif
/* Convince lint that some things are used */
# ifdef LINT
{
extern char * GC_copyright[];
extern GC_read();
GC_noop(GC_copyright, GC_find_header, GC_print_block_list,
GC_push_one, GC_call_with_alloc_lock, GC_read,
GC_print_hblkfreelist, GC_dont_expand);
}
# endif
}
void GC_enable_incremental()
{
# ifndef FIND_LEAK
DISABLE_SIGNALS();
LOCK();
if (!GC_is_initialized) {
GC_init_inner();
}
if (GC_words_allocd > 0) {
/* There may be unmarked reachable objects */
GC_gcollect_inner();
} /* else we're OK in assumeing everything's */
/* clean since nothing can point to an */
/* unmarked object. */
GC_dirty_init();
GC_read_dirty();
GC_incremental = TRUE;
UNLOCK();
ENABLE_SIGNALS();
# endif
}
/* A version of printf that is unlikely to call malloc, and is thus safer */
/* to call from the collector in case malloc has been bound to GC_malloc. */
/* Assumes that no more than 1023 characters are written at once. */
/* Assumes that all arguments have been converted to something of the */
/* same size as long, and that the format conversions expect something */
/* of that size. */
void GC_printf(format, a, b, c, d, e, f)
char * format;
long a, b, c, d, e, f;
{
char buf[1025];
if (GC_quiet) return;
buf[1024] = 0x15;
(void) sprintf(buf, format, a, b, c, d, e, f);
if (buf[1024] != 0x15) ABORT("GC_printf clobbered stack");
# ifdef OS2
/* We hope this doesn't allocate */
if (fwrite(buf, 1, strlen(buf), stdout) != strlen(buf))
ABORT("write to stdout failed");
# else
if (write(1, buf, strlen(buf)) < 0) ABORT("write to stdout failed");
# endif
}
void GC_err_printf(format, a, b, c, d, e, f)
char * format;
long a, b, c, d, e, f;
{
char buf[1025];
buf[1024] = 0x15;
(void) sprintf(buf, format, a, b, c, d, e, f);
if (buf[1024] != 0x15) ABORT("GC_err_printf clobbered stack");
# ifdef OS2
/* We hope this doesn't allocate */
if (fwrite(buf, 1, strlen(buf), stderr) != strlen(buf))
ABORT("write to stderr failed");
# else
if (write(2, buf, strlen(buf)) < 0) ABORT("write to stderr failed");
# endif
}
void GC_err_puts(s)
char *s;
{
# ifdef OS2
/* We hope this doesn't allocate */
if (fwrite(s, 1, strlen(s), stderr) != strlen(s))
ABORT("write to stderr failed");
# else
if (write(2, s, strlen(s)) < 0) ABORT("write to stderr failed");
# endif
}
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