+++ /dev/null
-/*
- * Copyright (c) 2010 Apple Inc. All Rights Reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-
-#include "objc-private.h"
-
-#include <malloc/malloc.h>
-#include <assert.h>
-#include "runtime.h"
-#include "objc-os.h"
-#include "message.h"
-#if SUPPORT_GC
-#include "auto_zone.h"
-#endif
-
-enum {
- // external references to data segment objects all use this type
- OBJC_XREF_TYPE_STATIC = 3,
-
- OBJC_XREF_TYPE_MASK = 3
-};
-
-// Macros to encode/decode reference values and types.
-#define encode_pointer_and_type(pointer, type) (~((uintptr_t)(pointer) | type))
-#define decode_pointer(encoded) ((id)((~(encoded)) & (~OBJC_XREF_TYPE_MASK)))
-#define decode_type(encoded) ((~(encoded)) & OBJC_XREF_TYPE_MASK)
-#define encode_index_and_type(index, type) (~((index<<3) | type))
-#define decode_index(encoded) ((~encoded)>>3)
-
-#if SUPPORT_GC
-
-typedef struct {
- objc_xref_type_t _type; // type of list.
- dispatch_queue_t _synchronizer; // a reader/write lock
- __strong void **_buffer; // a retained all pointers block
- size_t _size; // number of pointers that fit in _list (buffer size)
- size_t _count; // count of pointers in _list (in use count)
- size_t _search; // lowest index in list which *might* be unused
-} external_ref_list;
-
-static external_ref_list _xref_lists[2];
-
-#define is_strong(list) (list->_type == OBJC_XREF_STRONG)
-#define is_weak(list) (list->_type == OBJC_XREF_WEAK)
-
-inline static size_t _index_for_type(objc_xref_type_t ref_type) {
- assert(ref_type == OBJC_XREF_STRONG || ref_type == OBJC_XREF_WEAK);
- return (ref_type - 1);
-}
-
-static void _initialize_gc() {
- static dispatch_once_t init_guard;
- dispatch_once(&init_guard, ^{
- external_ref_list *_strong_list = &_xref_lists[_index_for_type(OBJC_XREF_STRONG)];
- _strong_list->_type = OBJC_XREF_STRONG;
- _strong_list->_synchronizer = dispatch_queue_create("OBJC_XREF_STRONG synchronizer", DISPATCH_QUEUE_CONCURRENT);
-
- external_ref_list *_weak_list = &_xref_lists[_index_for_type(OBJC_XREF_WEAK)];
- _weak_list->_type = OBJC_XREF_WEAK;
- _weak_list->_synchronizer = dispatch_queue_create("OBJC_XREF_WEAK synchronizer", DISPATCH_QUEUE_CONCURRENT);
- });
-}
-
-#define EMPTY_SLOT ((void*)0x1)
-
-// grow the buffer by one page
-static bool _grow_list(external_ref_list *list) {
- auto_memory_type_t memory_type = (is_strong(list) ? AUTO_MEMORY_ALL_POINTERS : AUTO_MEMORY_ALL_WEAK_POINTERS);
- size_t new_size = list->_size + PAGE_MAX_SIZE / sizeof(void *);
- // auto_realloc() has been enhanced to handle strong and weak memory.
- void **new_list = (void **)(list->_buffer ? malloc_zone_realloc(gc_zone, list->_buffer, new_size * sizeof(void *)) : auto_zone_allocate_object(gc_zone, new_size * sizeof(void *), memory_type, false, false));
- if (!new_list) _objc_fatal("unable to allocate, size = %ld\n", new_size);
-
- list->_search = list->_size;
- // Fill the newly allocated space with empty slot tokens.
- for (size_t index = list->_size; index < new_size; ++index)
- new_list[index] = EMPTY_SLOT;
- list->_size = new_size;
- auto_zone_root_write_barrier(gc_zone, &list->_buffer, new_list);
- return true;
-}
-
-
-// find an unused slot in the list, growing the list if necessary
-static size_t _find_unused_index(external_ref_list *list) {
- size_t index;
- if (list->_size == list->_count) {
- _grow_list(list);
- }
- // find the lowest unused index in _list
- index = list->_search;
- while (list->_buffer[index] != EMPTY_SLOT)
- index++;
- // mark the slot as no longer empty, good form for weak slots.
- list->_buffer[index] = NULL;
- return index;
-}
-
-
-// return the strong or weak list
-inline static external_ref_list *_list_for_type(objc_xref_type_t ref_type) {
- return &_xref_lists[_index_for_type(ref_type)];
-}
-
-
-// create a GC external reference
-objc_xref_t _object_addExternalReference_gc(id obj, objc_xref_type_t ref_type) {
- _initialize_gc();
- __block size_t index;
- objc_xref_t xref;
-
- if (auto_zone_is_valid_pointer(gc_zone, obj)) {
- external_ref_list *list = _list_for_type(ref_type);
-
- // writer lock
- dispatch_barrier_sync(list->_synchronizer, (dispatch_block_t)^{
- index = _find_unused_index(list);
- if (ref_type == OBJC_XREF_STRONG) {
- auto_zone_set_write_barrier(gc_zone, &list->_buffer[index], obj);
- } else {
- auto_assign_weak_reference(gc_zone, obj, (const void **)&list->_buffer[index], NULL);
- }
- list->_count++;
- });
- xref = encode_index_and_type(index, ref_type);
- } else {
- // data segment object
- xref = encode_pointer_and_type(obj, OBJC_XREF_TYPE_STATIC);
- }
- return xref;
-}
-
-
-id _object_readExternalReference_gc(objc_xref_t ref) {
- _initialize_gc();
- __block id result;
- objc_xref_type_t ref_type = decode_type(ref);
- if (ref_type != OBJC_XREF_TYPE_STATIC) {
- size_t index = decode_index(ref);
- external_ref_list *list = _list_for_type(ref_type);
-
- dispatch_sync(list->_synchronizer, ^{
- if (index >= list->_size) {
- _objc_fatal("attempted to resolve invalid external reference\n");
- }
- if (ref_type == OBJC_XREF_STRONG)
- result = (id)list->_buffer[index];
- else
- result = (id)auto_read_weak_reference(gc_zone, &list->_buffer[index]);
- if (result == (id)EMPTY_SLOT)
- _objc_fatal("attempted to resolve unallocated external reference\n");
- });
- } else {
- // data segment object
- result = decode_pointer(ref);
- }
- return result;
-}
-
-
-void _object_removeExternalReference_gc(objc_xref_t ref) {
- _initialize_gc();
- objc_xref_type_t ref_type = decode_type(ref);
- if (ref_type != OBJC_XREF_TYPE_STATIC) {
- size_t index = decode_index(ref);
- external_ref_list *list = _list_for_type(ref_type);
-
- dispatch_barrier_sync(list->_synchronizer, ^{
- if (index >= list->_size) {
- _objc_fatal("attempted to destroy invalid external reference\n");
- }
- id old_value;
- if (ref_type == OBJC_XREF_STRONG) {
- old_value = (id)list->_buffer[index];
- } else {
- old_value = (id)auto_read_weak_reference(gc_zone, &list->_buffer[index]);
- auto_assign_weak_reference(gc_zone, NULL, (const void **)&list->_buffer[index], NULL);
- }
- list->_buffer[index] = EMPTY_SLOT;
- if (old_value == (id)EMPTY_SLOT)
- _objc_fatal("attempted to destroy unallocated external reference\n");
- list->_count--;
- if (list->_search > index)
- list->_search = index;
- });
- } else {
- // nothing for data segment object
- }
-}
-
-
-// SUPPORT_GC
-#endif
-
-
-objc_xref_t _object_addExternalReference_non_gc(id obj, objc_xref_type_t ref_type) {
- switch (ref_type) {
- case OBJC_XREF_STRONG:
- ((id(*)(id, SEL))objc_msgSend)(obj, SEL_retain);
- break;
- case OBJC_XREF_WEAK:
- break;
- default:
- _objc_fatal("invalid external reference type: %d", (int)ref_type);
- break;
- }
- return encode_pointer_and_type(obj, ref_type);
-}
-
-
-id _object_readExternalReference_non_gc(objc_xref_t ref) {
- id obj = decode_pointer(ref);
- return obj;
-}
-
-
-void _object_removeExternalReference_non_gc(objc_xref_t ref) {
- id obj = decode_pointer(ref);
- objc_xref_type_t ref_type = decode_type(ref);
- switch (ref_type) {
- case OBJC_XREF_STRONG:
- ((void(*)(id, SEL))objc_msgSend)(obj, SEL_release);
- break;
- case OBJC_XREF_WEAK:
- break;
- default:
- _objc_fatal("invalid external reference type: %d", (int)ref_type);
- break;
- }
-}
-
-
-uintptr_t _object_getExternalHash(id object) {
- return (uintptr_t)object;
-}
-
-
-#if SUPPORT_GC
-
-// These functions are resolver functions in objc-auto.mm.
-
-#else
-
-objc_xref_t
-_object_addExternalReference(id obj, objc_xref_t type)
-{
- return _object_addExternalReference_non_gc(obj, type);
-}
-
-
-id
-_object_readExternalReference(objc_xref_t ref)
-{
- return _object_readExternalReference_non_gc(ref);
-}
-
-
-void
-_object_removeExternalReference(objc_xref_t ref)
-{
- _object_removeExternalReference_non_gc(ref);
-}
-
-#endif
projects / apple / objc4.git / blobdiff