X-Git-Url: https://git.saurik.com/apple/objc4.git/blobdiff_plain/7c0e6487d7b67b6bf6c632300ee4b74e8950b051..7af964d1562d70f51a8e9aca24215ac3d83d0624:/runtime/objc-sel.mm diff --git a/runtime/objc-sel.mm b/runtime/objc-sel.mm new file mode 100644 index 0000000..4b5e207 --- /dev/null +++ b/runtime/objc-sel.mm @@ -0,0 +1,362 @@ +/* + * 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 ""; +#endif + return sel ? (const char *)sel : ""; +} + + +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