/*
* 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"
#if SUPPORT_BUILTINS
#include "objc-selopt.h"
#endif
__BEGIN_DECLS
#if SUPPORT_BUILTINS
// opt: the actual opt used at runtime
// builtins: the actual selector table used at runtime
// _objc_opt_data: opt data possibly written by dyld
// empty_opt_data: empty data to use if dyld didn't cooperate or DisablePreopt
using namespace objc_opt;
static const objc_selopt_t *builtins = NULL;
static const objc_opt_t *opt = NULL;
static BOOL preoptimized;
extern const objc_opt_t _objc_opt_data; // in __TEXT, __objc_selopt
static const uint32_t empty_opt_data[] = OPT_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;
#if SUPPORT_BUILTINS
PRIVATE_EXTERN void dump_builtins(void)
{
uint32_t occupied = builtins->occupied;
uint32_t capacity = builtins->capacity;
_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: 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);
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);
}
}
}
#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;
#if SUPPORT_IGNORED_SELECTOR_CONSTANT
if ((uintptr_t)key == kIgnore) return (SEL)kIgnore;
if (ignoreSelectorNamed(key)) return (SEL)kIgnore;
#endif
if ('\0' == *key) return (SEL)_objc_empty_selector;
#if SUPPORT_BUILTINS
return (SEL)builtins->get(key);
#endif
return (SEL)0;
}
const char *sel_getName(SEL sel) {
#if SUPPORT_IGNORED_SELECTOR_CONSTANT
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 SUPPORT_IGNORED_SELECTOR_CONSTANT
if ((uintptr_t)name == kIgnore) return YES;
#endif
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)
{
#if !SUPPORT_BUILTINS
return NO;
#else
# if SUPPORT_IGNORED_SELECTOR_CONSTANT
// shared cache can't fix constant ignored selectors
if (UseGC) return NO;
# endif
// preoptimization disabled for some reason
if (!preoptimized) return NO;
// image not from shared cache, or not fixed inside shared cache
if (!_objcHeaderOptimizedByDyld(hi)) return NO;
return YES;
#endif
}
/***********************************************************************
* sel_init
* Initialize selector tables and register selectors used internally.
**********************************************************************/
PRIVATE_EXTERN void sel_init(BOOL wantsGC)
{
#if !SUPPORT_BUILTINS
disableSharedCacheOptimizations();
#else
// not set at compile time in order to detect too-early selector operations
const char *failure = NULL;
opt = &_objc_opt_data;
if (DisablePreopt) {
// OBJC_DISABLE_PREOPTIMIZATION is set
// If opt->version != VERSION then you continue at your own risk.
failure = "(by OBJC_DISABLE_PREOPTIMIZATION)";
}
else if (opt->version != objc_opt::VERSION) {
// This shouldn't happen. You probably forgot to
// change OPT_INITIALIZER and objc-sel-table.s.
// If dyld really did write the wrong optimization version,
// then we must halt because we don't know what bits dyld twiddled.
_objc_fatal("bad objc opt version (want %d, got %d)",
objc_opt::VERSION, opt->version);
}
else if (!opt->selopt()) {
// No selector table. dyld must not have written one.
failure = "(dyld shared cache is absent or out of date)";
}
#if SUPPORT_IGNORED_SELECTOR_CONSTANT
else if (UseGC) {
// GC is on, which renames some selectors
// Non-selector optimizations are still valid, but we don't have
// any of those yet
failure = "(GC is on)";
}
#endif
if (failure) {
// All preoptimized selector references are invalid.
preoptimized = NO;
opt = (objc_opt_t *)empty_opt_data;
builtins = opt->selopt();
disableSharedCacheOptimizations();
if (PrintPreopt) {
_objc_inform("PREOPTIMIZATION: is DISABLED %s", failure);
}
}
else {
// Valid optimization data written by dyld shared cache
preoptimized = YES;
builtins = opt->selopt();
if (PrintPreopt) {
_objc_inform("PREOPTIMIZATION: is ENABLED "
"(version %d)", opt->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(retainCount);
s(alloc);
s(copy);
s(new);
s(finalize);
t(forwardInvocation:, forwardInvocation);
sel_unlock();
#undef s
#undef t
}
__END_DECLS