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mallocx.c
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mallocx.c
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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996 by Silicon Graphics. All rights reserved.
* Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved.
* Copyright (c) 2009-2022 Ivan Maidanski
*
* 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 "private/gc_priv.h"
/*
* These are extra allocation routines which are likely to be less
* frequently used than those in malloc.c. They are separate in the
* hope that the .o file will be excluded from statically linked
* executables. We should probably break this up further.
*/
#include <string.h>
#ifndef MSWINCE
# include <errno.h>
#endif
/* Some externally visible but unadvertised variables to allow access to */
/* free lists from inlined allocators without including gc_priv.h */
/* or introducing dependencies on internal data structure layouts. */
#include "private/gc_alloc_ptrs.h"
void ** const GC_objfreelist_ptr = GC_objfreelist;
void ** const GC_aobjfreelist_ptr = GC_aobjfreelist;
void ** const GC_uobjfreelist_ptr = GC_uobjfreelist;
# ifdef GC_ATOMIC_UNCOLLECTABLE
void ** const GC_auobjfreelist_ptr = GC_auobjfreelist;
# endif
GC_API int GC_CALL GC_get_kind_and_size(const void * p, size_t * psize)
{
const hdr *hhdr = HDR(p);
if (psize != NULL) {
*psize = hhdr -> hb_sz;
}
return hhdr -> hb_obj_kind;
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_generic_or_special_malloc(size_t lb,
int k)
{
switch (k) {
case PTRFREE:
case NORMAL:
return GC_malloc_kind(lb, k);
case UNCOLLECTABLE:
# ifdef GC_ATOMIC_UNCOLLECTABLE
case AUNCOLLECTABLE:
# endif
return GC_generic_malloc_uncollectable(lb, k);
default:
return GC_generic_malloc_aligned(lb, k, 0 /* flags */, 0);
}
}
/* Change the size of the block pointed to by p to contain at least */
/* lb bytes. The object may be (and quite likely will be) moved. */
/* The kind (e.g. atomic) is the same as that of the old. */
/* Shrinking of large blocks is not implemented well. */
GC_API void * GC_CALL GC_realloc(void * p, size_t lb)
{
hdr * hhdr;
void * result;
# if defined(_FORTIFY_SOURCE) && defined(__GNUC__) && !defined(__clang__)
/* Use cleared_p instead of p as a workaround to avoid */
/* passing alloc_size(lb) attribute associated with p to */
/* memset (including a memset call inside GC_free). */
volatile GC_uintptr_t cleared_p = (GC_uintptr_t)p;
# else
# define cleared_p p
# endif
size_t sz; /* Current size in bytes */
size_t orig_sz; /* Original sz in bytes */
int obj_kind;
if (NULL == p) return GC_malloc(lb); /* Required by ANSI */
if (0 == lb) /* and p != NULL */ {
# ifndef IGNORE_FREE
GC_free(p);
# endif
return NULL;
}
hhdr = HDR(HBLKPTR(p));
sz = hhdr -> hb_sz;
obj_kind = hhdr -> hb_obj_kind;
orig_sz = sz;
if (sz > MAXOBJBYTES) {
const struct obj_kind * ok = &GC_obj_kinds[obj_kind];
word descr = ok -> ok_descriptor;
/* Round it up to the next whole heap block. */
sz = (sz + HBLKSIZE-1) & ~(HBLKSIZE-1);
# if ALIGNMENT > GC_DS_TAGS
/* An extra byte is not added in case of ignore-off-page */
/* allocated objects not smaller than HBLKSIZE. */
GC_ASSERT(sz >= HBLKSIZE);
if (EXTRA_BYTES != 0 && (hhdr -> hb_flags & IGNORE_OFF_PAGE) != 0
&& obj_kind == NORMAL)
descr += ALIGNMENT; /* or set to 0 */
# endif
if (ok -> ok_relocate_descr)
descr += sz;
/* GC_realloc might be changing the block size while */
/* GC_reclaim_block or GC_clear_hdr_marks is examining it. */
/* The change to the size field is benign, in that GC_reclaim */
/* (and GC_clear_hdr_marks) would work correctly with either */
/* value, since we are not changing the number of objects in */
/* the block. But seeing a half-updated value (though unlikely */
/* to occur in practice) could be probably bad. */
/* Using unordered atomic accesses on the size and hb_descr */
/* fields would solve the issue. (The alternate solution might */
/* be to initially overallocate large objects, so we do not */
/* have to adjust the size in GC_realloc, if they still fit. */
/* But that is probably more expensive, since we may end up */
/* scanning a bunch of zeros during GC.) */
# ifdef AO_HAVE_store
AO_store(&(hhdr -> hb_sz), sz);
AO_store((AO_t *)&(hhdr -> hb_descr), descr);
# else
{
LOCK();
hhdr -> hb_sz = sz;
hhdr -> hb_descr = descr;
UNLOCK();
}
# endif
# ifdef MARK_BIT_PER_OBJ
GC_ASSERT(hhdr -> hb_inv_sz == LARGE_INV_SZ);
# else
GC_ASSERT((hhdr -> hb_flags & LARGE_BLOCK) != 0
&& hhdr -> hb_map[ANY_INDEX] == 1);
# endif
if (IS_UNCOLLECTABLE(obj_kind)) GC_non_gc_bytes += (sz - orig_sz);
/* Extra area is already cleared by GC_alloc_large_and_clear. */
}
if (ADD_EXTRA_BYTES(lb) <= sz) {
if (lb >= (sz >> 1)) {
if (orig_sz > lb) {
/* Clear unneeded part of object to avoid bogus pointer */
/* tracing. */
BZERO((ptr_t)cleared_p + lb, orig_sz - lb);
}
return p;
}
/* shrink */
sz = lb;
}
result = GC_generic_or_special_malloc((word)lb, obj_kind);
if (EXPECT(result != NULL, TRUE)) {
/* In case of shrink, it could also return original object. */
/* But this gives the client warning of imminent disaster. */
BCOPY(p, result, sz);
# ifndef IGNORE_FREE
GC_free((ptr_t)cleared_p);
# endif
}
return result;
# undef cleared_p
}
# if defined(REDIRECT_MALLOC) && !defined(REDIRECT_REALLOC)
# define REDIRECT_REALLOC GC_realloc
# endif
# ifdef REDIRECT_REALLOC
/* As with malloc, avoid two levels of extra calls here. */
# define GC_debug_realloc_replacement(p, lb) \
GC_debug_realloc(p, lb, GC_DBG_EXTRAS)
# if !defined(REDIRECT_MALLOC_IN_HEADER)
void * realloc(void * p, size_t lb)
{
return REDIRECT_REALLOC(p, lb);
}
# endif
# undef GC_debug_realloc_replacement
# endif /* REDIRECT_REALLOC */
/* Allocate memory such that only pointers to near the beginning of */
/* the object are considered. We avoid holding the allocator lock */
/* while we clear the memory. */
GC_API GC_ATTR_MALLOC void * GC_CALL
GC_generic_malloc_ignore_off_page(size_t lb, int k)
{
return GC_generic_malloc_aligned(lb, k, IGNORE_OFF_PAGE, 0 /* align_m1 */);
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_ignore_off_page(size_t lb)
{
return GC_generic_malloc_aligned(lb, NORMAL, IGNORE_OFF_PAGE, 0);
}
GC_API GC_ATTR_MALLOC void * GC_CALL
GC_malloc_atomic_ignore_off_page(size_t lb)
{
return GC_generic_malloc_aligned(lb, PTRFREE, IGNORE_OFF_PAGE, 0);
}
/* Increment GC_bytes_allocd from code that doesn't have direct access */
/* to GC_arrays. */
void GC_CALL GC_incr_bytes_allocd(size_t n)
{
GC_bytes_allocd += n;
}
/* The same for GC_bytes_freed. */
void GC_CALL GC_incr_bytes_freed(size_t n)
{
GC_bytes_freed += n;
}
GC_API size_t GC_CALL GC_get_expl_freed_bytes_since_gc(void)
{
return (size_t)GC_bytes_freed;
}
# ifdef PARALLEL_MARK
/* Number of bytes of memory allocated since we released the */
/* allocator lock. Instead of reacquiring the allocator lock just */
/* to add this in, we add it in the next time we reacquire the */
/* allocator lock. (Atomically adding it does not work, since we */
/* would have to atomically update it in GC_malloc, which is too */
/* expensive.) */
STATIC volatile AO_t GC_bytes_allocd_tmp = 0;
# endif /* PARALLEL_MARK */
GC_API void GC_CALL GC_generic_malloc_many(size_t lb_adjusted, int k,
void **result)
{
void *op;
void *p;
void **opp;
size_t lg; /* lb_adjusted value converted to granules */
word my_bytes_allocd = 0;
struct obj_kind *ok;
struct hblk **rlh;
GC_ASSERT(lb_adjusted != 0 && (lb_adjusted & (GC_GRANULE_BYTES-1)) == 0);
/* Currently a single object is always allocated if manual VDB. */
/* TODO: GC_dirty should be called for each linked object (but */
/* the last one) to support multiple objects allocation. */
if (!EXPECT(lb_adjusted <= MAXOBJBYTES, TRUE) || GC_manual_vdb) {
op = GC_generic_malloc_aligned(lb_adjusted - EXTRA_BYTES, k,
0 /* flags */, 0 /* align_m1 */);
if (EXPECT(op != NULL, TRUE))
obj_link(op) = NULL;
*result = op;
# ifndef NO_MANUAL_VDB
if (GC_manual_vdb && GC_is_heap_ptr(result)) {
GC_dirty_inner(result);
REACHABLE_AFTER_DIRTY(op);
}
# endif
return;
}
GC_ASSERT(k < MAXOBJKINDS);
lg = BYTES_TO_GRANULES(lb_adjusted);
if (EXPECT(get_have_errors(), FALSE))
GC_print_all_errors();
GC_INVOKE_FINALIZERS();
GC_DBG_COLLECT_AT_MALLOC(lb_adjusted - EXTRA_BYTES);
if (!EXPECT(GC_is_initialized, TRUE)) GC_init();
LOCK();
/* Do our share of marking work */
if (GC_incremental && !GC_dont_gc) {
ENTER_GC();
GC_collect_a_little_inner(1);
EXIT_GC();
}
/* First see if we can reclaim a page of objects waiting to be */
/* reclaimed. */
ok = &GC_obj_kinds[k];
rlh = ok -> ok_reclaim_list;
if (rlh != NULL) {
struct hblk * hbp;
hdr * hhdr;
while ((hbp = rlh[lg]) != NULL) {
hhdr = HDR(hbp);
rlh[lg] = hhdr -> hb_next;
GC_ASSERT(hhdr -> hb_sz == lb_adjusted);
hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
# ifdef PARALLEL_MARK
if (GC_parallel) {
signed_word my_bytes_allocd_tmp =
(signed_word)AO_load(&GC_bytes_allocd_tmp);
GC_ASSERT(my_bytes_allocd_tmp >= 0);
/* We only decrement it while holding the allocator */
/* lock. Thus, we cannot accidentally adjust it down */
/* in more than one thread simultaneously. */
if (my_bytes_allocd_tmp != 0) {
(void)AO_fetch_and_add(&GC_bytes_allocd_tmp,
(AO_t)(-my_bytes_allocd_tmp));
GC_bytes_allocd += (word)my_bytes_allocd_tmp;
}
GC_acquire_mark_lock();
++GC_fl_builder_count;
UNLOCK();
GC_release_mark_lock();
}
# endif
op = GC_reclaim_generic(hbp, hhdr, lb_adjusted,
ok -> ok_init, 0, &my_bytes_allocd);
if (op != 0) {
# ifdef PARALLEL_MARK
if (GC_parallel) {
*result = op;
(void)AO_fetch_and_add(&GC_bytes_allocd_tmp,
(AO_t)my_bytes_allocd);
GC_acquire_mark_lock();
--GC_fl_builder_count;
if (GC_fl_builder_count == 0) GC_notify_all_builder();
# ifdef THREAD_SANITIZER
GC_release_mark_lock();
LOCK();
GC_bytes_found += (signed_word)my_bytes_allocd;
UNLOCK();
# else
GC_bytes_found += (signed_word)my_bytes_allocd;
/* The result may be inaccurate. */
GC_release_mark_lock();
# endif
(void)GC_clear_stack(0);
return;
}
# endif
/* We also reclaimed memory, so we need to adjust */
/* that count. */
GC_bytes_found += (signed_word)my_bytes_allocd;
GC_bytes_allocd += my_bytes_allocd;
goto out;
}
# ifdef PARALLEL_MARK
if (GC_parallel) {
GC_acquire_mark_lock();
--GC_fl_builder_count;
if (GC_fl_builder_count == 0) GC_notify_all_builder();
GC_release_mark_lock();
LOCK();
/* The allocator lock is needed for access to the */
/* reclaim list. We must decrement fl_builder_count */
/* before reacquiring the allocator lock. Hopefully */
/* this path is rare. */
rlh = ok -> ok_reclaim_list; /* reload rlh after locking */
if (NULL == rlh) break;
}
# endif
}
}
/* Next try to use prefix of global free list if there is one. */
/* We don't refill it, but we need to use it up before allocating */
/* a new block ourselves. */
opp = &(ok -> ok_freelist[lg]);
if ((op = *opp) != NULL) {
*opp = NULL;
my_bytes_allocd = 0;
for (p = op; p != NULL; p = obj_link(p)) {
my_bytes_allocd += lb_adjusted;
if ((word)my_bytes_allocd >= HBLKSIZE) {
*opp = obj_link(p);
obj_link(p) = NULL;
break;
}
}
GC_bytes_allocd += my_bytes_allocd;
goto out;
}
/* Next try to allocate a new block worth of objects of this size. */
{
struct hblk *h = GC_allochblk(lb_adjusted, k, 0 /* flags */,
0 /* align_m1 */);
if (h /* != NULL */) { /* CPPCHECK */
if (IS_UNCOLLECTABLE(k)) GC_set_hdr_marks(HDR(h));
GC_bytes_allocd += HBLKSIZE - (HBLKSIZE % lb_adjusted);
# ifdef PARALLEL_MARK
if (GC_parallel) {
GC_acquire_mark_lock();
++GC_fl_builder_count;
UNLOCK();
GC_release_mark_lock();
op = GC_build_fl(h, NULL, lg,
ok -> ok_init || GC_debugging_started);
*result = op;
GC_acquire_mark_lock();
--GC_fl_builder_count;
if (GC_fl_builder_count == 0) GC_notify_all_builder();
GC_release_mark_lock();
(void)GC_clear_stack(0);
return;
}
# endif
op = GC_build_fl(h, NULL, lg, ok -> ok_init || GC_debugging_started);
goto out;
}
}
/* As a last attempt, try allocating a single object. Note that */
/* this may trigger a collection or expand the heap. */
op = GC_generic_malloc_inner(lb_adjusted - EXTRA_BYTES, k, 0 /* flags */);
if (op != NULL) obj_link(op) = NULL;
out:
*result = op;
UNLOCK();
(void)GC_clear_stack(0);
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_many(size_t lb)
{
void *result;
size_t lg, lb_adjusted;
if (EXPECT(0 == lb, FALSE)) lb = 1;
lg = ALLOC_REQUEST_GRANS(lb);
lb_adjusted = GRANULES_TO_BYTES(lg);
GC_generic_malloc_many(lb_adjusted, NORMAL, &result);
return result;
}
/* TODO: The debugging version of GC_memalign and friends is tricky */
/* and currently missing. The major difficulty is: */
/* - store_debug_info() should return the pointer of the object with */
/* the requested alignment (unlike the object header). */
GC_API GC_ATTR_MALLOC void * GC_CALL GC_memalign(size_t align, size_t lb)
{
size_t align_m1 = align - 1;
/* Check the alignment argument. */
if (EXPECT(0 == align || (align & align_m1) != 0, FALSE)) return NULL;
/* TODO: use thread-local allocation */
if (align <= GC_GRANULE_BYTES) return GC_malloc(lb);
return GC_malloc_kind_aligned_global(lb, NORMAL, align_m1);
}
/* This one exists largely to redirect posix_memalign for leaks finding. */
GC_API int GC_CALL GC_posix_memalign(void **memptr, size_t align, size_t lb)
{
void *p;
size_t align_minus_one = align - 1; /* to workaround a cppcheck warning */
/* Check alignment properly. */
if (EXPECT(align < sizeof(void *)
|| (align_minus_one & align) != 0, FALSE)) {
# ifdef MSWINCE
return ERROR_INVALID_PARAMETER;
# else
return EINVAL;
# endif
}
p = GC_memalign(align, lb);
if (EXPECT(NULL == p, FALSE)) {
# ifdef MSWINCE
return ERROR_NOT_ENOUGH_MEMORY;
# else
return ENOMEM;
# endif
}
*memptr = p;
return 0; /* success */
}
#ifndef GC_NO_VALLOC
GC_API GC_ATTR_MALLOC void * GC_CALL GC_valloc(size_t lb)
{
if (!EXPECT(GC_is_initialized, TRUE)) GC_init();
GC_ASSERT(GC_real_page_size != 0);
return GC_memalign(GC_real_page_size, lb);
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_pvalloc(size_t lb)
{
if (!EXPECT(GC_is_initialized, TRUE)) GC_init();
GC_ASSERT(GC_real_page_size != 0);
lb = SIZET_SAT_ADD(lb, GC_real_page_size - 1) & ~(GC_real_page_size - 1);
return GC_memalign(GC_real_page_size, lb);
}
#endif /* !GC_NO_VALLOC */
/* Provide a version of strdup() that uses the collector to allocate */
/* the copy of the string. */
GC_API GC_ATTR_MALLOC char * GC_CALL GC_strdup(const char *s)
{
char *copy;
size_t lb;
if (s == NULL) return NULL;
lb = strlen(s) + 1;
copy = (char *)GC_malloc_atomic(lb);
if (EXPECT(NULL == copy, FALSE)) {
# ifndef MSWINCE
errno = ENOMEM;
# endif
return NULL;
}
BCOPY(s, copy, lb);
return copy;
}
GC_API GC_ATTR_MALLOC char * GC_CALL GC_strndup(const char *str, size_t size)
{
char *copy;
size_t len = strlen(str); /* str is expected to be non-NULL */
if (EXPECT(len > size, FALSE))
len = size;
copy = (char *)GC_malloc_atomic(len + 1);
if (EXPECT(NULL == copy, FALSE)) {
# ifndef MSWINCE
errno = ENOMEM;
# endif
return NULL;
}
if (EXPECT(len > 0, TRUE))
BCOPY(str, copy, len);
copy[len] = '\0';
return copy;
}
#ifdef GC_REQUIRE_WCSDUP
# include <wchar.h> /* for wcslen() */
GC_API GC_ATTR_MALLOC wchar_t * GC_CALL GC_wcsdup(const wchar_t *str)
{
size_t lb = (wcslen(str) + 1) * sizeof(wchar_t);
wchar_t *copy = (wchar_t *)GC_malloc_atomic(lb);
if (EXPECT(NULL == copy, FALSE)) {
# ifndef MSWINCE
errno = ENOMEM;
# endif
return NULL;
}
BCOPY(str, copy, lb);
return copy;
}
#endif /* GC_REQUIRE_WCSDUP */
#ifndef CPPCHECK
GC_API void * GC_CALL GC_malloc_stubborn(size_t lb)
{
return GC_malloc(lb);
}
GC_API void GC_CALL GC_change_stubborn(const void *p)
{
UNUSED_ARG(p);
}
#endif /* !CPPCHECK */
GC_API void GC_CALL GC_end_stubborn_change(const void *p)
{
GC_dirty(p); /* entire object */
}
GC_API void GC_CALL GC_ptr_store_and_dirty(void *p, const void *q)
{
*(const void **)p = q;
GC_dirty(p);
REACHABLE_AFTER_DIRTY(q);
}