+/*
+ * Copyright (c) 1999-2007 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@
+ */
+
+/*
+ * Utilities for registering and looking up selectors. The sole
+ * purpose of the selector tables is a registry whereby there is
+ * exactly one address (selector) associated with a given string
+ * (method name).
+ */
+
+#include "objc.h"
+#include "objc-private.h"
+#include "objc-auto.h"
+#include "objc-sel-set.h"
+
+#ifndef NO_BUILTINS
+#include "objc-selopt.h"
+#endif
+
+__BEGIN_DECLS
+
+#ifndef NO_BUILTINS
+// builtins: the actual table used at runtime
+// _objc_selopt_data: the usual builtin table, possibly rewritten by dyld
+// empty_selopt_data: an empty table to use if DisablePreopt is set
+using namespace objc_selopt;
+static const objc_selopt_t *builtins = NULL;
+extern const objc_selopt_t _objc_selopt_data; // in __TEXT, __objc_selopt
+static const uint32_t empty_selopt_data[] = SELOPT_INITIALIZER;
+#endif
+
+
+#define NUM_NONBUILTIN_SELS 3500
+// objc_sel_set grows at 3571, 5778, 9349.
+// Most apps use 2000..7000 extra sels. Most apps will grow zero to two times.
+
+static const char *_objc_empty_selector = "";
+static struct __objc_sel_set *_objc_selectors = NULL;
+
+
+#ifndef NO_GC
+static inline int ignore_selector(const char *sel)
+{
+ // force retain/release/autorelease to be a constant value when GC is on
+ // note that the selectors for "Protocol" are registered before we can
+ // see the executable image header that sets _WantsGC, so we can't cache
+ // this result (sigh).
+ return (UseGC &&
+ ( (sel[0] == 'r' && sel[1] == 'e' &&
+ (_objc_strcmp(&sel[2], "lease") == 0 ||
+ _objc_strcmp(&sel[2], "tain") == 0 ||
+ _objc_strcmp(&sel[2], "tainCount") == 0 ))
+ ||
+ (_objc_strcmp(sel, "dealloc") == 0)
+ ||
+ (sel[0] == 'a' && sel[1] == 'u' &&
+ _objc_strcmp(&sel[2], "torelease") == 0)));
+}
+#endif
+
+
+#ifndef NO_BUILTINS
+__private_extern__ void dump_builtins(void)
+{
+ if (builtins->version != VERSION) {
+ _objc_inform("BUILTIN SELECTORS: unknown version %d (want %d)",
+ builtins->version, VERSION);
+ return;
+ }
+
+ uint32_t occupied = builtins->occupied;
+ uint32_t capacity = builtins->capacity;
+
+ const int32_t *offsets = builtins->offsets();
+ uint32_t i;
+ for (i = 0; i < capacity; i++) {
+ if (offsets[i] != offsetof(objc_selopt_t, zero)) {
+ const char *str = (const char *)builtins + offsets[i];
+ _objc_inform("BUILTIN SELECTORS: %6d: %+8d %s",
+ i, offsets[i], str);
+ } else {
+ _objc_inform("BUILTIN SELECTORS: %6d: ", i);
+ }
+ }
+
+ _objc_inform("BUILTIN SELECTORS: %d selectors", occupied);
+ _objc_inform("BUILTIN SELECTORS: %d/%d (%d%%) hash table occupancy",
+ occupied, capacity, (int)(occupied/(double)capacity * 100));
+ _objc_inform("BUILTIN SELECTORS: using __TEXT,__objc_selopt at %p",
+ builtins);
+ _objc_inform("BUILTIN SELECTORS: version: %u", builtins->version);
+ _objc_inform("BUILTIN SELECTORS: capacity: %u", builtins->capacity);
+ _objc_inform("BUILTIN SELECTORS: occupied: %u", builtins->occupied);
+ _objc_inform("BUILTIN SELECTORS: shift: %u", builtins->shift);
+ _objc_inform("BUILTIN SELECTORS: mask: 0x%x", builtins->mask);
+ _objc_inform("BUILTIN SELECTORS: zero: %u", builtins->zero);
+ _objc_inform("BUILTIN SELECTORS: salt: 0x%llx", builtins->salt);
+ _objc_inform("BUILTIN SELECTORS: base: 0x%llx", builtins->base);
+}
+#endif
+
+
+static SEL _objc_search_builtins(const char *key)
+{
+#if defined(DUMP_SELECTORS)
+ if (NULL != key) printf("\t\"%s\",\n", key);
+#endif
+
+ if (!key) return (SEL)0;
+#ifndef NO_GC
+ if ((uintptr_t)key == kIgnore) return (SEL)kIgnore;
+ if (ignore_selector(key)) return (SEL)kIgnore;
+#endif
+ if ('\0' == *key) return (SEL)_objc_empty_selector;
+
+#ifndef NO_BUILTINS
+ return (SEL)builtins->get(key);
+#endif
+
+ return (SEL)0;
+}
+
+
+const char *sel_getName(SEL sel) {
+#ifndef NO_GC
+ if ((uintptr_t)sel == kIgnore) return "<ignored selector>";
+#endif
+ return sel ? (const char *)sel : "<null selector>";
+}
+
+
+BOOL sel_isMapped(SEL name)
+{
+ SEL result;
+
+ if (!name) return NO;
+ if ((uintptr_t)name == kIgnore) return YES;
+
+ result = _objc_search_builtins((const char *)name);
+ if (result) return YES;
+
+ rwlock_read(&selLock);
+ if (_objc_selectors) {
+ result = __objc_sel_set_get(_objc_selectors, name);
+ }
+ rwlock_unlock_read(&selLock);
+ return result ? YES : NO;
+}
+
+static SEL __sel_registerName(const char *name, int lock, int copy)
+{
+ SEL result = 0;
+
+ if (lock) rwlock_assert_unlocked(&selLock);
+ else rwlock_assert_writing(&selLock);
+
+ if (!name) return (SEL)0;
+ result = _objc_search_builtins(name);
+ if (result) return result;
+
+ if (lock) rwlock_read(&selLock);
+ if (_objc_selectors) {
+ result = __objc_sel_set_get(_objc_selectors, (SEL)name);
+ }
+ if (lock) rwlock_unlock_read(&selLock);
+ if (result) return result;
+
+ // No match. Insert.
+
+ if (lock) rwlock_write(&selLock);
+
+ if (!_objc_selectors) {
+ _objc_selectors = __objc_sel_set_create(NUM_NONBUILTIN_SELS);
+ }
+ if (lock) {
+ // Rescan in case it was added while we dropped the lock
+ result = __objc_sel_set_get(_objc_selectors, (SEL)name);
+ }
+ if (!result) {
+ result = (SEL)(copy ? _strdup_internal(name) : name);
+ __objc_sel_set_add(_objc_selectors, result);
+#if defined(DUMP_UNKNOWN_SELECTORS)
+ printf("\t\"%s\",\n", name);
+#endif
+ }
+
+ if (lock) rwlock_unlock_write(&selLock);
+ return result;
+}
+
+
+SEL sel_registerName(const char *name) {
+ return __sel_registerName(name, 1, 1); // YES lock, YES copy
+}
+
+__private_extern__ SEL sel_registerNameNoLock(const char *name, BOOL copy) {
+ return __sel_registerName(name, 0, copy); // NO lock, maybe copy
+}
+
+__private_extern__ void sel_lock(void)
+{
+ rwlock_write(&selLock);
+}
+
+__private_extern__ void sel_unlock(void)
+{
+ rwlock_unlock_write(&selLock);
+}
+
+
+// 2001/1/24
+// the majority of uses of this function (which used to return NULL if not found)
+// did not check for NULL, so, in fact, never return NULL
+//
+SEL sel_getUid(const char *name) {
+ return __sel_registerName(name, 2, 1); // YES lock, YES copy
+}
+
+
+BOOL sel_isEqual(SEL lhs, SEL rhs)
+{
+ return (lhs == rhs) ? YES : NO;
+}
+
+
+/***********************************************************************
+* sel_preoptimizationValid
+* Return YES if this image's selector fixups are valid courtesy
+* of the dyld shared cache.
+**********************************************************************/
+__private_extern__ BOOL sel_preoptimizationValid(const header_info *hi)
+{
+#ifdef NO_BUILTINS
+
+ return NO;
+
+#else
+
+# ifndef NO_GC
+ // shared cache can't fix ignored selectors
+ if (UseGC) return NO;
+# endif
+
+ // image not from shared cache, or not fixed inside shared cache
+ if (!_objcHeaderOptimizedByDyld(hi)) return NO;
+
+ // libobjc not from shared cache, or from shared cache but slid
+ if (builtins->base != (uintptr_t)builtins) return NO;
+
+ return YES;
+
+#endif
+}
+
+
+/***********************************************************************
+* sel_init
+* Initialize selector tables and register selectors used internally.
+**********************************************************************/
+__private_extern__ void sel_init(BOOL wantsGC)
+{
+#ifdef NO_BUILTINS
+
+ disableSelectorPreoptimization();
+
+#else
+ // not set at compile time in order to detect too-early selector operations
+ builtins = &_objc_selopt_data;
+
+ // Check selector table (possibly built by dyld shared cache)
+ if (builtins->base == (uintptr_t)builtins && !UseGC && !DisablePreopt) {
+ // Valid selector table written by dyld shared cache
+ if (PrintPreopt) {
+ _objc_inform("PREOPTIMIZATION: selector preoptimization ENABLED "
+ "(version %d)", builtins->version);
+ }
+ }
+ else {
+ // Selector table written by dyld shared cache, but slid
+ // OR selector table not written by dyld shared cache
+ // OR gc is on which renames ignored selectors
+ // OR disabled by environment variable
+ // All preoptimized selector references are invalid.
+
+ // But keep the builtins table itself unless disabled by environment
+ if (DisablePreopt) builtins = (objc_selopt_t *)empty_selopt_data;
+
+ disableSelectorPreoptimization();
+
+ if (PrintPreopt) {
+ const char *why;
+ if (DisablePreopt) why = "(by OBJC_DISABLE_PREOPTIMIZATION)";
+ else if (UseGC) why = "(GC is on)";
+ else why = "(dyld shared cache is absent or out of date)";
+ _objc_inform("PREOPTIMIZATION: selector preoptimization DISABLED %s", why);
+ }
+ }
+
+ // Die if the table looks bad.
+ // We should always end up with a good dyld table,
+ // or the compiled-in table, or the compiled-in empty table.
+ // Failure probably means you forgot to update the compiled-in table data.
+ // Don't do this before checking DisablePreopt.
+ if (builtins->version != VERSION) {
+ _objc_fatal("bad objc selector table (want %d, got %d)",
+ VERSION, builtins->version);
+ }
+
+#endif
+
+ // Register selectors used by libobjc
+
+ if (wantsGC) {
+ // Registering retain/release/autorelease requires GC decision first.
+ // sel_init doesn't actually need the wantsGC parameter, it just
+ // helps enforce the initialization order.
+ }
+
+#define s(x) SEL_##x = sel_registerNameNoLock(#x, NO)
+#define t(x,y) SEL_##y = sel_registerNameNoLock(#x, NO)
+
+ sel_lock();
+
+ s(load);
+ s(initialize);
+ t(resolveInstanceMethod:, resolveInstanceMethod);
+ t(resolveClassMethod:, resolveClassMethod);
+ t(.cxx_construct, cxx_construct);
+ t(.cxx_destruct, cxx_destruct);
+ s(retain);
+ s(release);
+ s(autorelease);
+ s(copy);
+ s(finalize);
+
+ sel_unlock();
+
+#undef s
+#undef t
+}
+
+__END_DECLS
projects / apple / objc4.git / blobdiff