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typd_mlc.c
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typd_mlc.c
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/*
* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
* Copyright (c) 1999-2000 by Hewlett-Packard Company. All rights reserved.
* Copyright (c) 2008-2022 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_pmark.h"
/*
* Some simple primitives for allocation with explicit type information.
* Simple objects are allocated such that they contain a GC_descr at the
* end (in the last allocated word). This descriptor may be a procedure
* which then examines an extended descriptor passed as its environment.
*
* Arrays are treated as simple objects if they have sufficiently simple
* structure. Otherwise they are allocated from an array kind that supplies
* a special mark procedure. These arrays contain a pointer to a
* complex_descriptor as their last "pointer-sized" word.
* This is done because the environment field is too small, and the collector
* must trace the complex_descriptor.
*
* Note that descriptors inside objects may appear cleared, if we encounter
* a false reference to an object on a free list. In the case of a simple
* object, this is OK, since a zero descriptor corresponds to examining no
* fields. In the complex_descriptor case, we explicitly check for that case.
*
* MAJOR PARTS OF THIS CODE HAVE NOT BEEN TESTED AT ALL and are not testable,
* since they are not accessible through the current interface.
*/
#include "gc/gc_typed.h"
STATIC int GC_explicit_kind = 0;
/* Object kind for objects with indirect */
/* (possibly extended) descriptors. */
STATIC int GC_array_kind = 0;
/* Object kind for objects with complex */
/* descriptors and GC_array_mark_proc. */
#define ED_INITIAL_SIZE 100
STATIC unsigned GC_typed_mark_proc_index = 0; /* Indices of the typed */
STATIC unsigned GC_array_mark_proc_index = 0; /* mark procedures. */
STATIC void GC_push_typed_structures_proc(void)
{
GC_PUSH_ALL_SYM(GC_ext_descriptors);
}
/* Add a multi-word bitmap to GC_ext_descriptors arrays. */
/* Returns starting index on success, -1 otherwise. */
STATIC signed_word GC_add_ext_descriptor(const word * bm, size_t nbits)
{
signed_word result;
size_t i;
size_t nwords = divWORDSZ(nbits + CPP_WORDSZ-1);
LOCK();
while (EXPECT(GC_avail_descr + nwords >= GC_ed_size, FALSE)) {
typed_ext_descr_t *newExtD;
size_t new_size;
size_t ed_size = GC_ed_size;
if (0 == ed_size) {
GC_ASSERT(ADDR(&GC_ext_descriptors) % sizeof(ptr_t) == 0);
GC_push_typed_structures = GC_push_typed_structures_proc;
UNLOCK();
new_size = ED_INITIAL_SIZE;
} else {
UNLOCK();
new_size = 2 * ed_size;
if (new_size > MAX_ENV) return -1;
}
newExtD = (typed_ext_descr_t*)GC_malloc_atomic(new_size
* sizeof(typed_ext_descr_t));
if (NULL == newExtD)
return -1;
LOCK();
if (ed_size == GC_ed_size) {
if (GC_avail_descr != 0) {
BCOPY(GC_ext_descriptors, newExtD,
GC_avail_descr * sizeof(typed_ext_descr_t));
}
GC_ed_size = new_size;
GC_ext_descriptors = newExtD;
} /* else another thread already resized it in the meantime */
}
result = (signed_word)GC_avail_descr;
for (i = 0; i < nwords - 1; i++) {
GC_ext_descriptors[(size_t)result + i].ed_bitmap = bm[i];
GC_ext_descriptors[(size_t)result + i].ed_continued = TRUE;
}
/* Clear irrelevant (highest) bits for the last element. */
GC_ext_descriptors[(size_t)result + i].ed_bitmap =
bm[i] & (GC_WORD_MAX >> (nwords * CPP_WORDSZ - nbits));
GC_ext_descriptors[(size_t)result + i].ed_continued = FALSE;
GC_avail_descr += nwords;
GC_ASSERT(result >= 0);
UNLOCK();
return result;
}
/* Table of bitmap descriptors for n pointer-long all-pointer objects. */
STATIC GC_descr GC_bm_table[CPP_WORDSZ / 2];
/* Return a descriptor for the concatenation of 2 objects, each one is */
/* lpw pointers long and described by descriptor d. The result is */
/* known to be short enough to fit into a bitmap descriptor. */
/* d is a GC_DS_LENGTH or GC_DS_BITMAP descriptor. */
STATIC GC_descr GC_double_descr(GC_descr d, size_t lpw)
{
GC_ASSERT(GC_bm_table[0] == GC_DS_BITMAP); /* bm table is initialized */
if ((d & GC_DS_TAGS) == GC_DS_LENGTH) {
d = GC_bm_table[BYTES_TO_PTRS(d)];
}
d |= (d & ~(GC_descr)GC_DS_TAGS) >> lpw;
return d;
}
STATIC mse *GC_CALLBACK GC_typed_mark_proc(word *addr, mse *mark_stack_top,
mse *mark_stack_limit, word env);
STATIC mse *GC_CALLBACK GC_array_mark_proc(word *addr, mse *mark_stack_top,
mse *mark_stack_limit, word env);
STATIC void GC_init_explicit_typing(void)
{
unsigned i;
/* Set up object kind with simple indirect descriptor. */
/* Descriptor is in the last word of the object. */
GC_typed_mark_proc_index = GC_new_proc_inner(GC_typed_mark_proc);
GC_explicit_kind = (int)GC_new_kind_inner(GC_new_free_list_inner(),
(PTRS_TO_BYTES(GC_WORD_MAX) | GC_DS_PER_OBJECT),
TRUE, TRUE);
/* Set up object kind with array descriptor. */
GC_array_mark_proc_index = GC_new_proc_inner(GC_array_mark_proc);
GC_array_kind = (int)GC_new_kind_inner(GC_new_free_list_inner(),
GC_MAKE_PROC(GC_array_mark_proc_index, 0),
FALSE, TRUE);
GC_bm_table[0] = GC_DS_BITMAP;
for (i = 1; i < CPP_WORDSZ / 2; i++) {
GC_bm_table[i] = (GC_WORD_MAX << (CPP_WORDSZ - i)) | GC_DS_BITMAP;
}
}
STATIC mse *GC_CALLBACK GC_typed_mark_proc(word *addr, mse *mark_stack_top,
mse *mark_stack_limit, word env)
{
word bm;
ptr_t current_p = (ptr_t)addr;
ptr_t greatest_ha = (ptr_t)GC_greatest_plausible_heap_addr;
ptr_t least_ha = (ptr_t)GC_least_plausible_heap_addr;
DECLARE_HDR_CACHE;
/* The allocator lock is held by the collection initiating thread. */
GC_ASSERT(GC_get_parallel() || I_HOLD_LOCK());
bm = GC_ext_descriptors[env].ed_bitmap;
INIT_HDR_CACHE;
for (; bm != 0; bm >>= 1, current_p += sizeof(ptr_t)) {
if (bm & 1) {
ptr_t q;
LOAD_PTR_OR_CONTINUE(q, current_p);
FIXUP_POINTER(q);
if (ADDR_LT(least_ha, q) && ADDR_LT(q, greatest_ha)) {
PUSH_CONTENTS(q, mark_stack_top, mark_stack_limit, current_p);
}
}
}
if (GC_ext_descriptors[env].ed_continued) {
/* Push an entry with the rest of the descriptor back onto the */
/* stack. Thus we never do too much work at once. Note that */
/* we also can't overflow the mark stack unless we actually */
/* mark something. */
mark_stack_top = GC_custom_push_proc(
GC_MAKE_PROC(GC_typed_mark_proc_index, env + 1),
(ptr_t *)addr + CPP_WORDSZ, mark_stack_top,
mark_stack_limit);
}
return mark_stack_top;
}
GC_API GC_descr GC_CALL GC_make_descriptor(const GC_word * bm, size_t len)
{
signed_word last_set_bit = (signed_word)len - 1;
GC_descr d;
# if defined(AO_HAVE_load_acquire) && defined(AO_HAVE_store_release)
if (!EXPECT(AO_load_acquire(&GC_explicit_typing_initialized), TRUE)) {
LOCK();
if (!GC_explicit_typing_initialized) {
GC_init_explicit_typing();
AO_store_release(&GC_explicit_typing_initialized, TRUE);
}
UNLOCK();
}
# else
LOCK();
if (!EXPECT(GC_explicit_typing_initialized, TRUE)) {
GC_init_explicit_typing();
GC_explicit_typing_initialized = TRUE;
}
UNLOCK();
# endif
while (last_set_bit >= 0 && !GC_get_bit(bm, (word)last_set_bit))
last_set_bit--;
if (last_set_bit < 0) return 0; /* no pointers */
# if ALIGNMENT == CPP_PTRSZ / 8
{
signed_word i;
for (i = 0; i < last_set_bit; i++) {
if (!GC_get_bit(bm, (word)i))
break;
}
if (i == last_set_bit) {
/* The initial section contains all pointers; use the */
/* length descriptor. */
return PTRS_TO_BYTES((word)last_set_bit + 1) | GC_DS_LENGTH;
}
}
# endif
if (last_set_bit < BITMAP_BITS) {
signed_word i;
/* Hopefully the common case. Build the bitmap descriptor */
/* (with the bits reversed). */
d = SIGNB;
for (i = last_set_bit - 1; i >= 0; i--) {
d >>= 1;
if (GC_get_bit(bm, (word)i)) d |= SIGNB;
}
d |= GC_DS_BITMAP;
} else {
signed_word index = GC_add_ext_descriptor(bm,
(size_t)last_set_bit + 1);
if (EXPECT(index < 0, FALSE)) {
/* Out of memory: use a conservative approximation. */
return PTRS_TO_BYTES((word)last_set_bit + 1) | GC_DS_LENGTH;
}
# ifdef LINT2
if ((word)index > MAX_ENV)
ABORT("GC_add_ext_descriptor() result cannot exceed MAX_ENV");
# endif
d = GC_MAKE_PROC(GC_typed_mark_proc_index, index);
}
return d;
}
static void set_obj_descr(ptr_t op, GC_descr d)
{
size_t sz;
if (EXPECT(NULL == op, FALSE)) return;
/* It is not safe to use GC_size_map[] here as the table might be */
/* updated asynchronously. */
sz = GC_size(op);
GC_ASSERT((sz & (GC_GRANULE_BYTES-1)) == 0 && sz > sizeof(GC_descr));
# ifdef AO_HAVE_store_release
AO_store_release((volatile AO_t *)&op[sz - sizeof(GC_descr)], d);
# else
*(GC_descr *)&op[sz - sizeof(GC_descr)] = d;
# endif
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_explicitly_typed(size_t lb,
GC_descr d)
{
ptr_t op;
GC_ASSERT(GC_explicit_typing_initialized);
if (EXPECT(lb < sizeof(ptr_t) - sizeof(GC_descr) + 1, FALSE)) {
/* Ensure the descriptor does not occupy the first pointer place. */
lb = sizeof(ptr_t) - sizeof(GC_descr) + 1;
}
op = (ptr_t)GC_malloc_kind(
SIZET_SAT_ADD(lb, sizeof(GC_descr) - EXTRA_BYTES),
GC_explicit_kind);
set_obj_descr(op, d);
return op;
}
GC_API GC_ATTR_MALLOC void * GC_CALL
GC_malloc_explicitly_typed_ignore_off_page(size_t lb, GC_descr d)
{
ptr_t op;
if (lb < HBLKSIZE - sizeof(GC_descr))
return GC_malloc_explicitly_typed(lb, d);
GC_ASSERT(GC_explicit_typing_initialized);
/* Note that ignore-off-page objects with the requested size */
/* of at least HBLKSIZE do not have EXTRA_BYTES added by */
/* GC_generic_malloc_aligned(). */
op = (ptr_t)GC_clear_stack(GC_generic_malloc_aligned(
SIZET_SAT_ADD(lb, sizeof(GC_descr)),
GC_explicit_kind, IGNORE_OFF_PAGE, 0));
set_obj_descr(op, d);
return op;
}
/* Array descriptors. GC_array_mark_proc understands these. */
/* We may eventually need to add provisions for headers and */
/* trailers. Hence we provide for tree structured descriptors, */
/* though we don't really use them currently. */
struct LeafDescriptor { /* Describes simple array. */
word ld_tag;
# define LEAF_TAG 1
size_t ld_size; /* Bytes per element; non-zero, */
/* multiple of ALIGNMENT. */
size_t ld_nelements; /* Number of elements. */
GC_descr ld_descriptor; /* A simple length, bitmap, */
/* or procedure descriptor. */
};
struct ComplexArrayDescriptor {
word ad_tag;
# define ARRAY_TAG 2
size_t ad_nelements;
union ComplexDescriptor *ad_element_descr;
};
struct SequenceDescriptor {
word sd_tag;
# define SEQUENCE_TAG 3
union ComplexDescriptor *sd_first;
union ComplexDescriptor *sd_second;
};
typedef union ComplexDescriptor {
struct LeafDescriptor ld;
struct ComplexArrayDescriptor ad;
struct SequenceDescriptor sd;
} complex_descriptor;
STATIC complex_descriptor *GC_make_leaf_descriptor(size_t size,
size_t nelements,
GC_descr d)
{
complex_descriptor *result = (complex_descriptor *)
GC_malloc_atomic(sizeof(struct LeafDescriptor));
GC_ASSERT(size != 0);
if (EXPECT(NULL == result, FALSE)) return NULL;
result -> ld.ld_tag = LEAF_TAG;
result -> ld.ld_size = size;
result -> ld.ld_nelements = nelements;
result -> ld.ld_descriptor = d;
return result;
}
STATIC complex_descriptor *GC_make_sequence_descriptor(
complex_descriptor *first,
complex_descriptor *second)
{
struct SequenceDescriptor *result = (struct SequenceDescriptor *)
GC_malloc(sizeof(struct SequenceDescriptor));
/* Note: for a reason, the sanitizer runtime complains */
/* of insufficient space for complex_descriptor if the */
/* pointer type of result variable is changed to. */
if (EXPECT(NULL == result, FALSE)) return NULL;
/* Can't result in overly conservative marking, since tags are */
/* very small integers. Probably faster than maintaining type info. */
result -> sd_tag = SEQUENCE_TAG;
result -> sd_first = first;
result -> sd_second = second;
GC_dirty(result);
REACHABLE_AFTER_DIRTY(first);
REACHABLE_AFTER_DIRTY(second);
return (complex_descriptor *)result;
}
#define NO_MEM (-1)
#define SIMPLE 0
#define LEAF 1
#define COMPLEX 2
/* Build a descriptor for an array with nelements elements, each of */
/* which can be described by a simple descriptor d. We try to optimize */
/* some common cases. If the result is COMPLEX, a complex_descriptor* */
/* value is returned in *pcomplex_d. If the result is LEAF, then a */
/* LeafDescriptor value is built in the structure pointed to by pleaf. */
/* The tag in the *pleaf structure is not set. If the result is */
/* SIMPLE, then a GC_descr value is returned in *psimple_d. If the */
/* result is NO_MEM, then we failed to allocate the descriptor. */
/* The implementation assumes GC_DS_LENGTH is 0. *pleaf, *pcomplex_d */
/* and *psimple_d may be used as temporaries during the construction. */
STATIC int GC_make_array_descriptor(size_t nelements, size_t size,
GC_descr d, GC_descr *psimple_d,
complex_descriptor **pcomplex_d,
struct LeafDescriptor *pleaf)
{
# define OPT_THRESHOLD 50
/* For larger arrays, we try to combine descriptors of adjacent */
/* descriptors to speed up marking, and to reduce the amount */
/* of space needed on the mark stack. */
GC_ASSERT(size != 0);
if ((d & GC_DS_TAGS) == GC_DS_LENGTH) {
if (d == (GC_descr)size) {
*psimple_d = nelements * d; /* no overflow guaranteed by caller */
return SIMPLE;
} else if (0 == d) {
*psimple_d = 0;
return SIMPLE;
}
}
if (nelements <= OPT_THRESHOLD) {
if (nelements <= 1) {
*psimple_d = nelements == 1 ? d : 0;
return SIMPLE;
}
} else if (size <= BITMAP_BITS / 2
&& (d & GC_DS_TAGS) != GC_DS_PROC
&& (size & (sizeof(ptr_t)-1)) == 0) {
complex_descriptor *one_element, *beginning;
int result = GC_make_array_descriptor(nelements / 2, 2 * size,
GC_double_descr(d, BYTES_TO_PTRS(size)),
psimple_d, pcomplex_d, pleaf);
if ((nelements & 1) == 0 || EXPECT(NO_MEM == result, FALSE))
return result;
one_element = GC_make_leaf_descriptor(size, 1, d);
if (EXPECT(NULL == one_element, FALSE)) return NO_MEM;
if (COMPLEX == result) {
beginning = *pcomplex_d;
} else {
beginning = SIMPLE == result
? GC_make_leaf_descriptor(size, 1, *psimple_d)
: GC_make_leaf_descriptor(pleaf -> ld_size,
pleaf -> ld_nelements,
pleaf -> ld_descriptor);
if (EXPECT(NULL == beginning, FALSE)) return NO_MEM;
}
*pcomplex_d = GC_make_sequence_descriptor(beginning, one_element);
if (EXPECT(NULL == *pcomplex_d, FALSE)) return NO_MEM;
return COMPLEX;
}
pleaf -> ld_size = size;
pleaf -> ld_nelements = nelements;
pleaf -> ld_descriptor = d;
return LEAF;
}
struct GC_calloc_typed_descr_s {
complex_descriptor *complex_d; /* the first field, the only pointer */
struct LeafDescriptor leaf;
GC_descr simple_d;
word alloc_lb; /* size_t actually */
signed_word descr_type; /* int actually */
};
GC_API int GC_CALL GC_calloc_prepare_explicitly_typed(
struct GC_calloc_typed_descr_s *pctd,
size_t ctd_sz,
size_t n, size_t lb, GC_descr d)
{
GC_STATIC_ASSERT(sizeof(struct GC_calloc_typed_descr_s)
== GC_CALLOC_TYPED_DESCR_PTRS * sizeof(ptr_t)
+ (GC_CALLOC_TYPED_DESCR_WORDS - GC_CALLOC_TYPED_DESCR_PTRS)
* sizeof(word));
GC_ASSERT(GC_explicit_typing_initialized);
GC_ASSERT(sizeof(struct GC_calloc_typed_descr_s) == ctd_sz);
(void)ctd_sz; /* unused currently */
if (EXPECT(0 == lb || 0 == n, FALSE)) lb = n = 1;
if (EXPECT((lb | n) > GC_SQRT_SIZE_MAX, FALSE) /* fast initial check */
&& n > GC_SIZE_MAX / lb) {
pctd -> alloc_lb = GC_SIZE_MAX; /* n*lb overflow */
pctd -> descr_type = NO_MEM;
/* The rest of the fields are unset. */
return 0; /* failure */
}
pctd -> descr_type = GC_make_array_descriptor(n, lb, d,
&(pctd -> simple_d),
&(pctd -> complex_d),
&(pctd -> leaf));
switch (pctd -> descr_type) {
case NO_MEM:
case SIMPLE:
pctd -> alloc_lb = (word)lb * n;
break;
case LEAF:
pctd -> alloc_lb
= SIZET_SAT_ADD(lb * n,
(BYTES_TO_PTRS_ROUNDUP(sizeof(struct LeafDescriptor))
+ 1) * sizeof(ptr_t) - EXTRA_BYTES);
break;
case COMPLEX:
pctd -> alloc_lb = SIZET_SAT_ADD(lb * n, sizeof(ptr_t) - EXTRA_BYTES);
break;
}
return 1; /* success */
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_calloc_do_explicitly_typed(
const struct GC_calloc_typed_descr_s *pctd,
size_t ctd_sz)
{
void *op;
size_t lpw_m1;
GC_ASSERT(sizeof(struct GC_calloc_typed_descr_s) == ctd_sz);
(void)ctd_sz; /* unused currently */
switch (pctd -> descr_type) {
case NO_MEM:
return (*GC_get_oom_fn())((size_t)(pctd -> alloc_lb));
case SIMPLE:
return GC_malloc_explicitly_typed((size_t)(pctd -> alloc_lb),
pctd -> simple_d);
case LEAF:
case COMPLEX:
break;
default:
ABORT_RET("Bad descriptor type");
return NULL;
}
op = GC_malloc_kind((size_t)(pctd -> alloc_lb), GC_array_kind);
if (EXPECT(NULL == op, FALSE))
return NULL;
lpw_m1 = BYTES_TO_PTRS(GC_size(op)) - 1;
if (pctd -> descr_type == LEAF) {
/* Set up the descriptor inside the object itself. */
struct LeafDescriptor *lp
= (struct LeafDescriptor *)((ptr_t *)op + lpw_m1
- BYTES_TO_PTRS_ROUNDUP(sizeof(struct LeafDescriptor)));
lp -> ld_tag = LEAF_TAG;
lp -> ld_size = pctd -> leaf.ld_size;
lp -> ld_nelements = pctd -> leaf.ld_nelements;
lp -> ld_descriptor = pctd -> leaf.ld_descriptor;
/* Hold the allocator lock (in the reader mode which should be */
/* enough) while writing the descriptor word to the object to */
/* ensure that the descriptor contents are seen by */
/* GC_array_mark_proc as expected. */
/* TODO: It should be possible to replace locking with the atomic */
/* operations (with the release barrier here) but, in this case, */
/* avoiding the acquire barrier in GC_array_mark_proc seems to */
/* be tricky as GC_mark_some might be invoked with the world */
/* running. */
READER_LOCK();
((struct LeafDescriptor **)op)[lpw_m1] = lp;
READER_UNLOCK_RELEASE();
} else {
# ifndef GC_NO_FINALIZATION
READER_LOCK();
((complex_descriptor **)op)[lpw_m1] = pctd -> complex_d;
READER_UNLOCK_RELEASE();
GC_dirty((ptr_t *)op + lpw_m1);
REACHABLE_AFTER_DIRTY(pctd -> complex_d);
/* Make sure the descriptor is cleared once there is any danger */
/* it may have been collected. */
if (EXPECT(GC_general_register_disappearing_link(
(void **)op + lpw_m1, op) == GC_NO_MEMORY, FALSE))
# endif
{
/* Couldn't register it due to lack of memory. Punt. */
return (*GC_get_oom_fn())((size_t)(pctd -> alloc_lb));
}
}
return op;
}
GC_API GC_ATTR_MALLOC void * GC_CALL GC_calloc_explicitly_typed(size_t n,
size_t lb,
GC_descr d)
{
struct GC_calloc_typed_descr_s ctd;
(void)GC_calloc_prepare_explicitly_typed(&ctd, sizeof(ctd), n, lb, d);
return GC_calloc_do_explicitly_typed(&ctd, sizeof(ctd));
}
/* Return the size of the object described by complex_d. It would be */
/* faster to store this directly, or to compute it as part of */
/* GC_push_complex_descriptor, but hopefully it does not matter. */
STATIC size_t GC_descr_obj_size(complex_descriptor *complex_d)
{
switch (complex_d -> ad.ad_tag) {
case LEAF_TAG:
return complex_d -> ld.ld_nelements * complex_d -> ld.ld_size;
case ARRAY_TAG:
return complex_d -> ad.ad_nelements
* GC_descr_obj_size(complex_d -> ad.ad_element_descr);
case SEQUENCE_TAG:
return GC_descr_obj_size(complex_d -> sd.sd_first)
+ GC_descr_obj_size(complex_d -> sd.sd_second);
default:
ABORT_RET("Bad complex descriptor");
return 0;
}
}
/* Push descriptors for the object with complex descriptor onto the */
/* mark stack. Return NULL if the mark stack overflowed. */
STATIC mse *GC_push_complex_descriptor(ptr_t current,
complex_descriptor *complex_d,
mse *msp, mse *msl)
{
size_t i, nelements;
size_t sz;
GC_descr d;
complex_descriptor *element_descr;
switch (complex_d -> ad.ad_tag) {
case LEAF_TAG:
d = complex_d -> ld.ld_descriptor;
nelements = complex_d -> ld.ld_nelements;
sz = complex_d -> ld.ld_size;
if (EXPECT(msl - msp <= (signed_word)nelements, FALSE)) return NULL;
GC_ASSERT(sz != 0);
for (i = 0; i < nelements; i++) {
msp++;
msp -> mse_start = current;
msp -> mse_descr = d;
current += sz;
}
break;
case ARRAY_TAG:
element_descr = complex_d -> ad.ad_element_descr;
nelements = complex_d -> ad.ad_nelements;
sz = GC_descr_obj_size(element_descr);
GC_ASSERT(sz != 0 || 0 == nelements);
for (i = 0; i < nelements; i++) {
msp = GC_push_complex_descriptor(current, element_descr, msp, msl);
if (EXPECT(NULL == msp, FALSE)) return NULL;
current += sz;
}
break;
case SEQUENCE_TAG:
sz = GC_descr_obj_size(complex_d -> sd.sd_first);
msp = GC_push_complex_descriptor(current, complex_d -> sd.sd_first,
msp, msl);
if (EXPECT(NULL == msp, FALSE)) return NULL;
GC_ASSERT(sz != 0);
current += sz;
msp = GC_push_complex_descriptor(current, complex_d -> sd.sd_second,
msp, msl);
break;
default:
ABORT("Bad complex descriptor");
}
return msp;
}
GC_ATTR_NO_SANITIZE_THREAD
static complex_descriptor *get_complex_descr(ptr_t *p, size_t lpw)
{
return (complex_descriptor *)p[lpw - 1];
}
/* Used by GC_calloc_do_explicitly_typed via GC_array_kind. */
STATIC mse *GC_CALLBACK GC_array_mark_proc(word *addr, mse *mark_stack_top,
mse *mark_stack_limit, word env)
{
size_t sz = HDR(addr) -> hb_sz;
size_t lpw = BYTES_TO_PTRS(sz);
complex_descriptor *complex_d = get_complex_descr((ptr_t *)addr, lpw);
mse *orig_mark_stack_top = mark_stack_top;
mse *new_mark_stack_top;
UNUSED_ARG(env);
if (NULL == complex_d) {
/* Found a reference to a free-list entry. Ignore it. */
return orig_mark_stack_top;
}
/* In use counts were already updated when array descriptor was */
/* pushed. Here we only replace it by subobject descriptors, so */
/* no update is necessary. */
new_mark_stack_top = GC_push_complex_descriptor((ptr_t)addr, complex_d,
mark_stack_top,
mark_stack_limit - 1);
if (NULL == new_mark_stack_top) {
/* Explicitly instruct Clang Static Analyzer that ptr is non-null. */
if (NULL == mark_stack_top) ABORT("Bad mark_stack_top");
/* Does not fit. Conservatively push the whole array as a unit and */
/* request a mark stack expansion. This cannot cause a mark stack */
/* overflow, since it replaces the original array entry. */
# ifdef PARALLEL_MARK
/* We might be using a local_mark_stack in parallel mode. */
if (GC_mark_stack + GC_mark_stack_size == mark_stack_limit)
# endif
{
GC_mark_stack_too_small = TRUE;
}
new_mark_stack_top = orig_mark_stack_top + 1;
new_mark_stack_top -> mse_start = (ptr_t)addr;
new_mark_stack_top -> mse_descr = sz | GC_DS_LENGTH;
} else {
/* Push descriptor itself. */
new_mark_stack_top++;
new_mark_stack_top -> mse_start = (ptr_t)((ptr_t *)addr + lpw - 1);
new_mark_stack_top -> mse_descr = sizeof(ptr_t) | GC_DS_LENGTH;
}
return new_mark_stack_top;
}