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php-src/Zend/zend_gc.c

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/*
+----------------------------------------------------------------------+
| Zend Engine |
+----------------------------------------------------------------------+
| Copyright (c) 1998-2014 Zend Technologies Ltd. (http://www.zend.com) |
+----------------------------------------------------------------------+
| This source file is subject to version 2.00 of the Zend license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.zend.com/license/2_00.txt. |
| If you did not receive a copy of the Zend license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@zend.com so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: David Wang <planetbeing@gmail.com> |
| Dmitry Stogov <dmitry@zend.com> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include "zend.h"
#include "zend_API.h"
/* one (0) is reserved */
#define GC_ROOT_BUFFER_MAX_ENTRIES 10001
#ifdef ZTS
ZEND_API int gc_globals_id;
#else
ZEND_API zend_gc_globals gc_globals;
#endif
#define GC_REMOVE_FROM_ROOTS(current) \
gc_remove_from_roots((current) TSRMLS_CC)
static zend_always_inline void gc_remove_from_roots(gc_root_buffer *root TSRMLS_DC)
{
root->next->prev = root->prev;
root->prev->next = root->next;
root->prev = GC_G(unused);
GC_G(unused) = root;
GC_BENCH_DEC(root_buf_length);
}
static void root_buffer_dtor(zend_gc_globals *gc_globals TSRMLS_DC)
{
if (gc_globals->buf) {
free(gc_globals->buf);
gc_globals->buf = NULL;
}
}
static void gc_globals_ctor_ex(zend_gc_globals *gc_globals TSRMLS_DC)
{
gc_globals->gc_enabled = 0;
gc_globals->gc_active = 0;
gc_globals->buf = NULL;
gc_globals->roots.next = &gc_globals->roots;
gc_globals->roots.prev = &gc_globals->roots;
gc_globals->unused = NULL;
gc_globals->next_to_free = NULL;
gc_globals->to_free.next = &gc_globals->to_free;
gc_globals->to_free.prev = &gc_globals->to_free;
gc_globals->gc_runs = 0;
gc_globals->collected = 0;
#if GC_BENCH
gc_globals->root_buf_length = 0;
gc_globals->root_buf_peak = 0;
gc_globals->zval_possible_root = 0;
gc_globals->zval_buffered = 0;
gc_globals->zval_remove_from_buffer = 0;
gc_globals->zval_marked_grey = 0;
#endif
}
ZEND_API void gc_globals_ctor(TSRMLS_D)
{
#ifdef ZTS
ts_allocate_id(&gc_globals_id, sizeof(zend_gc_globals), (ts_allocate_ctor) gc_globals_ctor_ex, (ts_allocate_dtor) root_buffer_dtor);
#else
gc_globals_ctor_ex(&gc_globals);
#endif
}
ZEND_API void gc_globals_dtor(TSRMLS_D)
{
#ifndef ZTS
root_buffer_dtor(&gc_globals TSRMLS_DC);
#endif
}
ZEND_API void gc_reset(TSRMLS_D)
{
GC_G(gc_runs) = 0;
GC_G(collected) = 0;
#if GC_BENCH
GC_G(root_buf_length) = 0;
GC_G(root_buf_peak) = 0;
GC_G(zval_possible_root) = 0;
GC_G(zval_buffered) = 0;
GC_G(zval_remove_from_buffer) = 0;
GC_G(zval_marked_grey) = 0;
#endif
GC_G(roots).next = &GC_G(roots);
GC_G(roots).prev = &GC_G(roots);
GC_G(to_free).next = &GC_G(to_free);
GC_G(to_free).prev = &GC_G(to_free);
if (GC_G(buf)) {
GC_G(unused) = NULL;
GC_G(first_unused) = GC_G(buf) + 1;
} else {
GC_G(unused) = NULL;
GC_G(first_unused) = NULL;
GC_G(last_unused) = NULL;
}
}
ZEND_API void gc_init(TSRMLS_D)
{
if (GC_G(buf) == NULL && GC_G(gc_enabled)) {
GC_G(buf) = (gc_root_buffer*) malloc(sizeof(gc_root_buffer) * GC_ROOT_BUFFER_MAX_ENTRIES);
GC_G(last_unused) = &GC_G(buf)[GC_ROOT_BUFFER_MAX_ENTRIES];
gc_reset(TSRMLS_C);
}
}
ZEND_API void gc_possible_root(zend_refcounted *ref TSRMLS_DC)
{
if (UNEXPECTED(GC_ADDRESS(ref->u.v.gc_info) &&
GC_GET_COLOR(ref->u.v.gc_info) == GC_BLACK &&
GC_ADDRESS(ref->u.v.gc_info) >= GC_G(last_unused) - GC_G(buf))) {
/* The given zval is a garbage that is going to be deleted by
* currently running GC */
return;
}
GC_BENCH_INC(zval_possible_root);
if (GC_GET_COLOR(ref->u.v.gc_info) == GC_BLACK) {
GC_SET_PURPLE(ref->u.v.gc_info);
if (!GC_ADDRESS(ref->u.v.gc_info)) {
gc_root_buffer *newRoot = GC_G(unused);
if (newRoot) {
GC_G(unused) = newRoot->prev;
} else if (GC_G(first_unused) != GC_G(last_unused)) {
newRoot = GC_G(first_unused);
GC_G(first_unused)++;
} else {
if (!GC_G(gc_enabled)) {
GC_SET_BLACK(ref->u.v.gc_info);
return;
}
ref->refcount++;
gc_collect_cycles(TSRMLS_C);
ref->refcount--;
newRoot = GC_G(unused);
if (!newRoot) {
return;
}
GC_SET_PURPLE(ref->u.v.gc_info);
GC_G(unused) = newRoot->prev;
}
newRoot->next = GC_G(roots).next;
newRoot->prev = &GC_G(roots);
GC_G(roots).next->prev = newRoot;
GC_G(roots).next = newRoot;
GC_SET_ADDRESS(ref->u.v.gc_info, newRoot - GC_G(buf));
newRoot->ref = ref;
GC_BENCH_INC(zval_buffered);
GC_BENCH_INC(root_buf_length);
GC_BENCH_PEAK(root_buf_peak, root_buf_length);
}
}
}
ZEND_API void gc_remove_from_buffer(zend_refcounted *ref TSRMLS_DC)
{
gc_root_buffer *root;
if (UNEXPECTED(GC_ADDRESS(ref->u.v.gc_info) &&
GC_GET_COLOR(ref->u.v.gc_info) == GC_BLACK &&
GC_ADDRESS(ref->u.v.gc_info) >= GC_G(last_unused) - GC_G(buf))) {
/* The given zval is a garbage that is going to be deleted by
* currently running GC */
return;
}
root = GC_G(buf) + GC_ADDRESS(ref->u.v.gc_info);
GC_BENCH_INC(zval_remove_from_buffer);
GC_REMOVE_FROM_ROOTS(root);
ref->u.v.gc_info = 0;
/* updete next root that is going to be freed */
if (GC_G(next_to_free) == root) {
GC_G(next_to_free) = root->next;
}
}
static void gc_scan_black(zend_refcounted *ref TSRMLS_DC)
{
HashTable *ht;
uint idx;
Bucket *p;
tail_call:
ht = NULL;
GC_SET_BLACK(ref->u.v.gc_info);
if (ref->u.v.type == IS_OBJECT && EG(objects_store).object_buckets) {
zend_object_get_gc_t get_gc;
zend_object *obj = (zend_object*)ref;
if (EXPECTED(IS_VALID(EG(objects_store).object_buckets[obj->handle]) &&
(get_gc = obj->handlers->get_gc) != NULL)) {
int i, n;
zval *table;
zval tmp;
HashTable *props;
ZVAL_OBJ(&tmp, obj);
props = get_gc(&tmp, &table, &n TSRMLS_CC);
while (n > 0 && !Z_REFCOUNTED(table[n-1])) n--;
for (i = 0; i < n; i++) {
if (Z_REFCOUNTED(table[i])) {
ref = Z_COUNTED(table[i]);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount++;
}
if (GC_GET_COLOR(ref->u.v.gc_info) != GC_BLACK) {
if (!props && i == n - 1) {
goto tail_call;
} else {
gc_scan_black(ref TSRMLS_CC);
}
}
}
}
if (!props) {
return;
}
ht = props;
}
} else if (ref->u.v.type == IS_ARRAY) {
if ((zend_array*)ref != &EG(symbol_table)) {
ht = &((zend_array*)ref)->ht;
}
} else if (ref->u.v.type == IS_REFERENCE) {
if (Z_REFCOUNTED(((zend_reference*)ref)->val)) {
if (UNEXPECTED(!EG(objects_store).object_buckets) &&
Z_TYPE(((zend_reference*)ref)->val) == IS_OBJECT) {
return;
}
ref = Z_COUNTED(((zend_reference*)ref)->val);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount++;
}
if (GC_GET_COLOR(ref->u.v.gc_info) != GC_BLACK) {
goto tail_call;
}
}
return;
}
if (!ht) return;
for (idx = 0; idx < ht->nNumUsed; idx++) {
p = ht->arData + idx;
if (!Z_REFCOUNTED(p->val)) continue;
ref = Z_COUNTED(p->val);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount++;
}
if (GC_GET_COLOR(ref->u.v.gc_info) != GC_BLACK) {
if (idx == ht->nNumUsed-1) {
goto tail_call;
} else {
gc_scan_black(ref TSRMLS_CC);
}
}
}
}
static void gc_mark_grey(zend_refcounted *ref TSRMLS_DC)
{
HashTable *ht;
uint idx;
Bucket *p;
tail_call:
if (GC_GET_COLOR(ref->u.v.gc_info) != GC_GREY) {
ht = NULL;
GC_BENCH_INC(zval_marked_grey);
GC_SET_COLOR(ref->u.v.gc_info, GC_GREY);
if (ref->u.v.type == IS_OBJECT && EG(objects_store).object_buckets) {
zend_object_get_gc_t get_gc;
zend_object *obj = (zend_object*)ref;
if (EXPECTED(IS_VALID(EG(objects_store).object_buckets[obj->handle]) &&
(get_gc = obj->handlers->get_gc) != NULL)) {
int i, n;
zval *table;
zval tmp;
ZVAL_OBJ(&tmp, obj);
HashTable *props = get_gc(&tmp, &table, &n TSRMLS_CC);
while (n > 0 && !Z_REFCOUNTED(table[n-1])) n--;
for (i = 0; i < n; i++) {
if (Z_REFCOUNTED(table[i])) {
ref = Z_COUNTED(table[i]);
if (ref->u.v.type != IS_ARRAY || ((zend_array*)ref) != &EG(symbol_table)) {
ref->refcount--;
}
if (!props && i == n - 1) {
goto tail_call;
} else {
gc_mark_grey(ref TSRMLS_CC);
}
}
}
if (!props) {
return;
}
ht = props;
}
} else if (ref->u.v.type == IS_ARRAY) {
if (((zend_array*)ref) == &EG(symbol_table)) {
GC_SET_BLACK(ref->u.v.gc_info);
} else {
ht = &((zend_array*)ref)->ht;
}
} else if (ref->u.v.type == IS_REFERENCE) {
if (Z_REFCOUNTED(((zend_reference*)ref)->val)) {
if (UNEXPECTED(!EG(objects_store).object_buckets) &&
Z_TYPE(((zend_reference*)ref)->val) == IS_OBJECT) {
return;
}
ref = Z_COUNTED(((zend_reference*)ref)->val);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount--;
}
goto tail_call;
}
return;
}
if (!ht) return;
for (idx = 0; idx < ht->nNumUsed; idx++) {
p = ht->arData + idx;
if (!Z_REFCOUNTED(p->val)) continue;
ref = Z_COUNTED(p->val);
if (ref->u.v.type != IS_ARRAY || ((zend_array*)ref) != &EG(symbol_table)) {
ref->refcount--;
}
if (idx == ht->nNumUsed-1) {
goto tail_call;
} else {
gc_mark_grey(ref TSRMLS_CC);
}
}
}
}
static void gc_mark_roots(TSRMLS_D)
{
gc_root_buffer *current = GC_G(roots).next;
while (current != &GC_G(roots)) {
if (GC_GET_COLOR(current->ref->u.v.gc_info) == GC_PURPLE) {
gc_mark_grey(current->ref TSRMLS_CC);
//??? } else {
//??? GC_SET_ADDRESS(current->ref->u.v.gc_info, 0);
//??? GC_REMOVE_FROM_ROOTS(current);
}
current = current->next;
}
}
static void gc_scan(zend_refcounted *ref TSRMLS_DC)
{
HashTable *ht;
uint idx;
Bucket *p;
tail_call:
if (GC_GET_COLOR(ref->u.v.gc_info) == GC_GREY) {
ht = NULL;
if (ref->refcount > 0) {
gc_scan_black(ref TSRMLS_CC);
} else {
GC_SET_COLOR(ref->u.v.gc_info, GC_WHITE);
if (ref->u.v.type == IS_OBJECT && EG(objects_store).object_buckets) {
zend_object_get_gc_t get_gc;
zend_object *obj = (zend_object*)ref;
if (EXPECTED(IS_VALID(EG(objects_store).object_buckets[obj->handle]) &&
(get_gc = obj->handlers->get_gc) != NULL)) {
int i, n;
zval *table;
zval tmp;
HashTable *props;
ZVAL_OBJ(&tmp, obj);
props = get_gc(&tmp, &table, &n TSRMLS_CC);
while (n > 0 && !Z_REFCOUNTED(table[n-1])) n--;
for (i = 0; i < n; i++) {
if (Z_REFCOUNTED(table[i])) {
ref = Z_COUNTED(table[i]);
if (!props && i == n - 1) {
goto tail_call;
} else {
gc_scan(ref TSRMLS_CC);
}
}
}
if (!props) {
return;
}
ht = props;
}
} else if (ref->u.v.type == IS_ARRAY) {
if ((zend_array*)ref == &EG(symbol_table)) {
GC_SET_BLACK(ref->u.v.gc_info);
} else {
ht = &((zend_array*)ref)->ht;
}
} else if (ref->u.v.type == IS_REFERENCE) {
if (Z_REFCOUNTED(((zend_reference*)ref)->val)) {
if (UNEXPECTED(!EG(objects_store).object_buckets) &&
Z_TYPE(((zend_reference*)ref)->val) == IS_OBJECT) {
return;
}
ref = Z_COUNTED(((zend_reference*)ref)->val);
goto tail_call;
}
return;
}
}
if (!ht) return;
for (idx = 0; idx < ht->nNumUsed; idx++) {
p = ht->arData + idx;
if (!Z_REFCOUNTED(p->val)) continue;
ref = Z_COUNTED(p->val);
if (idx == ht->nNumUsed-1) {
goto tail_call;
} else {
gc_scan(ref TSRMLS_CC);
}
}
}
}
static void gc_scan_roots(TSRMLS_D)
{
gc_root_buffer *current = GC_G(roots).next;
while (current != &GC_G(roots)) {
gc_scan(current->ref TSRMLS_CC);
current = current->next;
}
}
static int gc_collect_white(zend_refcounted *ref TSRMLS_DC)
{
int count = 0;
HashTable *ht;
uint idx;
Bucket *p;
tail_call:
if (ref->u.v.gc_info == GC_WHITE) {
ht = NULL;
GC_SET_BLACK(ref->u.v.gc_info);
/* don't count references for compatibilty ??? */
if (ref->u.v.type != IS_REFERENCE) {
count++;
}
if (ref->u.v.type == IS_OBJECT && EG(objects_store).object_buckets) {
zend_object_get_gc_t get_gc;
zend_object *obj = (zend_object*)ref;
/* PURPLE instead of BLACK to prevent buffering in nested gc calls */
//??? GC_SET_PURPLE(obj->gc.u.v.gc_info);
if (EXPECTED(IS_VALID(EG(objects_store).object_buckets[obj->handle]) &&
(get_gc = obj->handlers->get_gc) != NULL)) {
int i, n;
zval *table;
zval tmp;
HashTable *props;
ZVAL_OBJ(&tmp, obj);
props = get_gc(&tmp, &table, &n TSRMLS_CC);
while (n > 0 && !Z_REFCOUNTED(table[n-1])) {
/* count non-refcounted for compatibilty ??? */
if (Z_TYPE(table[n-1]) != IS_UNDEF) {
count++;
}
n--;
}
for (i = 0; i < n; i++) {
if (Z_REFCOUNTED(table[i])) {
ref = Z_COUNTED(table[i]);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount++;
}
if (!props && i == n - 1) {
goto tail_call;
} else {
count += gc_collect_white(ref TSRMLS_CC);
}
/* count non-refcounted for compatibilty ??? */
} else if (Z_TYPE(table[i]) != IS_UNDEF) {
count++;
}
}
if (!props) {
return count;
}
ht = props;
}
} else if (ref->u.v.type == IS_ARRAY) {
ht = &((zend_array*)ref)->ht;
} else if (ref->u.v.type == IS_REFERENCE) {
if (Z_REFCOUNTED(((zend_reference*)ref)->val)) {
if (UNEXPECTED(!EG(objects_store).object_buckets) &&
Z_TYPE(((zend_reference*)ref)->val) == IS_OBJECT) {
return count;
}
ref = Z_COUNTED(((zend_reference*)ref)->val);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount++;
}
goto tail_call;
}
return count;
}
if (!ht) return count;
for (idx = 0; idx < ht->nNumUsed; idx++) {
p = ht->arData + idx;
if (!Z_REFCOUNTED(p->val)) {
/* count non-refcounted for compatibilty ??? */
if (Z_TYPE(p->val) != IS_UNDEF) {
count++;
}
continue;
}
ref = Z_COUNTED(p->val);
if (ref->u.v.type != IS_ARRAY || (zend_array*)ref != &EG(symbol_table)) {
ref->refcount++;
}
if (idx == ht->nNumUsed-1) {
goto tail_call;
} else {
count += gc_collect_white(ref TSRMLS_CC);
}
}
}
return count;
}
static int gc_collect_roots(TSRMLS_D)
{
int count = 0;
gc_root_buffer *current = GC_G(roots).next;
while (current != &GC_G(roots)) {
GC_SET_ADDRESS(current->ref->u.v.gc_info, 0);
if (current->ref->u.v.gc_info == GC_WHITE) {
count += gc_collect_white(current->ref TSRMLS_CC);
GC_SET_ADDRESS(current->ref->u.v.gc_info, current - GC_G(buf));
} else {
GC_REMOVE_FROM_ROOTS(current);
}
current = current->next;
}
/* relink remaining roots into list to free */
if (GC_G(roots).next != &GC_G(roots)) {
if (GC_G(to_free).next == &GC_G(to_free)) {
/* move roots into list to free */
GC_G(to_free).next = GC_G(roots).next;
GC_G(to_free).prev = GC_G(roots).prev;
GC_G(to_free).next->prev = &GC_G(to_free);
GC_G(to_free).prev->next = &GC_G(to_free);
} else {
/* add roots into list to free */
GC_G(to_free).prev->next = GC_G(roots).next;
GC_G(roots).next->prev = GC_G(to_free).prev;
GC_G(roots).prev->next = &GC_G(to_free);
GC_G(to_free).prev = GC_G(roots).prev;
}
GC_G(roots).next = &GC_G(roots);
GC_G(roots).prev = &GC_G(roots);
}
return count;
}
ZEND_API int gc_collect_cycles(TSRMLS_D)
{
int count = 0;
if (GC_G(roots).next != &GC_G(roots)) {
gc_root_buffer *current, *orig_next_to_free;
zend_refcounted *p;
if (GC_G(gc_active)) {
return 0;
}
GC_G(gc_runs)++;
GC_G(gc_active) = 1;
gc_mark_roots(TSRMLS_C);
gc_scan_roots(TSRMLS_C);
count = gc_collect_roots(TSRMLS_C);
orig_next_to_free = GC_G(next_to_free);
GC_G(gc_active) = 0;
/* First call destructors */
current = GC_G(to_free).next;
while (current != &GC_G(to_free)) {
p = current->ref;
GC_G(next_to_free) = current->next;
if (p->u.v.type == IS_OBJECT) {
zend_object *obj = (zend_object*)p;
if (EG(objects_store).object_buckets &&
obj->handlers->dtor_obj &&
IS_VALID(EG(objects_store).object_buckets[obj->handle]) &&
!(obj->gc.u.v.flags & IS_OBJ_DESTRUCTOR_CALLED)) {
obj->gc.u.v.flags |= IS_OBJ_DESTRUCTOR_CALLED;
obj->gc.refcount++;
obj->handlers->dtor_obj(obj TSRMLS_CC);
obj->gc.refcount--;
}
}
current = GC_G(next_to_free);
}
/* Destroy zvals */
current = GC_G(to_free).next;
while (current != &GC_G(to_free)) {
p = current->ref;
GC_G(next_to_free) = current->next;
if (p->u.v.type == IS_OBJECT) {
zend_object *obj = (zend_object*)p;
if (EG(objects_store).object_buckets &&
IS_VALID(EG(objects_store).object_buckets[obj->handle])) {
obj->gc.u.v.type = IS_NULL;
zend_objects_store_free(obj TSRMLS_CC);
}
} else if (p->u.v.type == IS_ARRAY) {
zend_array *arr = (zend_array*)p;
arr->gc.u.v.type = IS_NULL;
zend_hash_destroy(&arr->ht);
GC_REMOVE_FROM_BUFFER(arr);
efree(arr);
} else if (p->u.v.type == IS_REFERENCE) {
zend_reference *ref = (zend_reference*)p;
ref->gc.u.v.type = IS_NULL;
if (EXPECTED(EG(objects_store).object_buckets != NULL) ||
Z_TYPE(ref->val) != IS_OBJECT) {
zval_dtor(&ref->val);
}
GC_REMOVE_FROM_BUFFER(ref);
efree(ref);
}
current = GC_G(next_to_free);
}
GC_G(collected) += count;
GC_G(next_to_free) = orig_next_to_free;
}
return count;
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* indent-tabs-mode: t
* End:
*/
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