runtime/objc-private.h

   1 /*
   2  * Copyright (c) 1999-2007 Apple Inc.  All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  *    objc-private.h
  25  *    Copyright 1988-1996, NeXT Software, Inc.
  26  */
  27
  28 #ifndef _OBJC_PRIVATE_H_
  29 #define _OBJC_PRIVATE_H_
  30
  31 #include "objc-config.h"
  32
  33 /* Isolate ourselves from the definitions of id and Class in the compiler
  34  * and public headers.
  35  */
  36
  37 #ifdef _OBJC_OBJC_H_
  38 #error include objc-private.h before other headers
  39 #endif
  40
  41 #define OBJC_TYPES_DEFINED 1
  42 #undef OBJC_OLD_DISPATCH_PROTOTYPES
  43 #define OBJC_OLD_DISPATCH_PROTOTYPES 0
  44
  45 #include <cstddef>  // for nullptr_t
  46 #include <stdint.h>
  47 #include <assert.h>
  48
  49 // An assert that's disabled for release builds but still ensures the expression compiles.
  50 #ifdef NDEBUG
  51 #define ASSERT(x) (void)sizeof(!(x))
  52 #else
  53 #define ASSERT(x) assert(x)
  54 #endif
  55
  56 struct objc_class;
  57 struct objc_object;
  58
  59 typedef struct objc_class *Class;
  60 typedef struct objc_object *id;
  61
  62 namespace {
  63     struct SideTable;
  64 };
  65
  66 #include "isa.h"
  67
  68 union isa_t {
  69     isa_t() { }
  70     isa_t(uintptr_t value) : bits(value) { }
  71
  72     Class cls;
  73     uintptr_t bits;
  74 #if defined(ISA_BITFIELD)
  75     struct {
  76         ISA_BITFIELD;  // defined in isa.h
  77     };
  78 #endif
  79 };
  80
  81
  82 struct objc_object {
  83 private:
  84     isa_t isa;
  85
  86 public:
  87
  88     // ISA() assumes this is NOT a tagged pointer object
  89     Class ISA();
  90
  91     // rawISA() assumes this is NOT a tagged pointer object or a non pointer ISA
  92     Class rawISA();
  93
  94     // getIsa() allows this to be a tagged pointer object
  95     Class getIsa();
  96
  97     uintptr_t isaBits() const;
  98
  99     // initIsa() should be used to init the isa of new objects only.
 100     // If this object already has an isa, use changeIsa() for correctness.
 101     // initInstanceIsa(): objects with no custom RR/AWZ
 102     // initClassIsa(): class objects
 103     // initProtocolIsa(): protocol objects
 104     // initIsa(): other objects
 105     void initIsa(Class cls /*nonpointer=false*/);
 106     void initClassIsa(Class cls /*nonpointer=maybe*/);
 107     void initProtocolIsa(Class cls /*nonpointer=maybe*/);
 108     void initInstanceIsa(Class cls, bool hasCxxDtor);
 109
 110     // changeIsa() should be used to change the isa of existing objects.
 111     // If this is a new object, use initIsa() for performance.
 112     Class changeIsa(Class newCls);
 113
 114     bool hasNonpointerIsa();
 115     bool isTaggedPointer();
 116     bool isBasicTaggedPointer();
 117     bool isExtTaggedPointer();
 118     bool isClass();
 119
 120     // object may have associated objects?
 121     bool hasAssociatedObjects();
 122     void setHasAssociatedObjects();
 123
 124     // object may be weakly referenced?
 125     bool isWeaklyReferenced();
 126     void setWeaklyReferenced_nolock();
 127
 128     // object may have -.cxx_destruct implementation?
 129     bool hasCxxDtor();
 130
 131     // Optimized calls to retain/release methods
 132     id retain();
 133     void release();
 134     id autorelease();
 135
 136     // Implementations of retain/release methods
 137     id rootRetain();
 138     bool rootRelease();
 139     id rootAutorelease();
 140     bool rootTryRetain();
 141     bool rootReleaseShouldDealloc();
 142     uintptr_t rootRetainCount();
 143
 144     // Implementation of dealloc methods
 145     bool rootIsDeallocating();
 146     void clearDeallocating();
 147     void rootDealloc();
 148
 149 private:
 150     void initIsa(Class newCls, bool nonpointer, bool hasCxxDtor);
 151
 152     // Slow paths for inline control
 153     id rootAutorelease2();
 154     uintptr_t overrelease_error();
 155
 156 #if SUPPORT_NONPOINTER_ISA
 157     // Unified retain count manipulation for nonpointer isa
 158     id rootRetain(bool tryRetain, bool handleOverflow);
 159     bool rootRelease(bool performDealloc, bool handleUnderflow);
 160     id rootRetain_overflow(bool tryRetain);
 161     uintptr_t rootRelease_underflow(bool performDealloc);
 162
 163     void clearDeallocating_slow();
 164
 165     // Side table retain count overflow for nonpointer isa
 166     void sidetable_lock();
 167     void sidetable_unlock();
 168
 169     void sidetable_moveExtraRC_nolock(size_t extra_rc, bool isDeallocating, bool weaklyReferenced);
 170     bool sidetable_addExtraRC_nolock(size_t delta_rc);
 171     size_t sidetable_subExtraRC_nolock(size_t delta_rc);
 172     size_t sidetable_getExtraRC_nolock();
 173 #endif
 174
 175     // Side-table-only retain count
 176     bool sidetable_isDeallocating();
 177     void sidetable_clearDeallocating();
 178
 179     bool sidetable_isWeaklyReferenced();
 180     void sidetable_setWeaklyReferenced_nolock();
 181
 182     id sidetable_retain();
 183     id sidetable_retain_slow(SideTable& table);
 184
 185     uintptr_t sidetable_release(bool performDealloc = true);
 186     uintptr_t sidetable_release_slow(SideTable& table, bool performDealloc = true);
 187
 188     bool sidetable_tryRetain();
 189
 190     uintptr_t sidetable_retainCount();
 191 #if DEBUG
 192     bool sidetable_present();
 193 #endif
 194 };
 195
 196
 197 #if __OBJC2__
 198 typedef struct method_t *Method;
 199 typedef struct ivar_t *Ivar;
 200 typedef struct category_t *Category;
 201 typedef struct property_t *objc_property_t;
 202 #else
 203 typedef struct old_method *Method;
 204 typedef struct old_ivar *Ivar;
 205 typedef struct old_category *Category;
 206 typedef struct old_property *objc_property_t;
 207 #endif
 208
 209 // Public headers
 210
 211 #include "objc.h"
 212 #include "runtime.h"
 213 #include "objc-os.h"
 214 #include "objc-abi.h"
 215 #include "objc-api.h"
 216 #include "objc-config.h"
 217 #include "objc-internal.h"
 218 #include "maptable.h"
 219 #include "hashtable2.h"
 220
 221 /* Do not include message.h here. */
 222 /* #include "message.h" */
 223
 224 #define __APPLE_API_PRIVATE
 225 #include "objc-gdb.h"
 226 #undef __APPLE_API_PRIVATE
 227
 228
 229 // Private headers
 230
 231 #include "objc-ptrauth.h"
 232
 233 #if __OBJC2__
 234 #include "objc-runtime-new.h"
 235 #else
 236 #include "objc-runtime-old.h"
 237 #endif
 238
 239 #include "objc-references.h"
 240 #include "objc-initialize.h"
 241 #include "objc-loadmethod.h"
 242
 243
 244 #if SUPPORT_PREOPT  &&  __cplusplus
 245 #include <objc-shared-cache.h>
 246 using objc_selopt_t = const objc_opt::objc_selopt_t;
 247 #else
 248 struct objc_selopt_t;
 249 #endif
 250
 251
 252 #define STRINGIFY(x) #x
 253 #define STRINGIFY2(x) STRINGIFY(x)
 254
 255 __BEGIN_DECLS
 256
 257 namespace objc {
 258
 259 struct SafeRanges {
 260 private:
 261     struct Range {
 262         uintptr_t start;
 263         uintptr_t end;
 264
 265         inline bool contains(uintptr_t ptr) const {
 266             uintptr_t m_start, m_end;
 267 #if __arm64__
 268             // <rdar://problem/48304934> Force the compiler to use ldp
 269             // we really don't want 2 loads and 2 jumps.
 270             __asm__(
 271 # if __LP64__
 272                     "ldp %x[one], %x[two], [%x[src]]"
 273 # else
 274                     "ldp %w[one], %w[two], [%x[src]]"
 275 # endif
 276                     : [one] "=r" (m_start), [two] "=r" (m_end)
 277                     : [src] "r" (this)
 278             );
 279 #else
 280             m_start = start;
 281             m_end = end;
 282 #endif
 283             return m_start <= ptr && ptr < m_end;
 284         }
 285     };
 286
 287     struct Range *ranges;
 288     uint32_t count;
 289     uint32_t size : 31;
 290     uint32_t sorted : 1;
 291
 292 public:
 293     inline bool contains(uint16_t witness, uintptr_t ptr) const {
 294         return witness < count && ranges[witness].contains(ptr);
 295     }
 296
 297     bool find(uintptr_t ptr, uint32_t &pos);
 298     void add(uintptr_t start, uintptr_t end);
 299     void remove(uintptr_t start, uintptr_t end);
 300 };
 301
 302 extern struct SafeRanges dataSegmentsRanges;
 303
 304 } // objc
 305
 306 struct header_info;
 307
 308 // Split out the rw data from header info.  For now put it in a huge array
 309 // that more than exceeds the space needed.  In future we'll just allocate
 310 // this in the shared cache builder.
 311 typedef struct header_info_rw {
 312
 313     bool getLoaded() const {
 314         return isLoaded;
 315     }
 316
 317     void setLoaded(bool v) {
 318         isLoaded = v ? 1: 0;
 319     }
 320
 321     bool getAllClassesRealized() const {
 322         return allClassesRealized;
 323     }
 324
 325     void setAllClassesRealized(bool v) {
 326         allClassesRealized = v ? 1: 0;
 327     }
 328
 329     header_info *getNext() const {
 330         return (header_info *)(next << 2);
 331     }
 332
 333     void setNext(header_info *v) {
 334         next = ((uintptr_t)v) >> 2;
 335     }
 336
 337 private:
 338 #ifdef __LP64__
 339     uintptr_t isLoaded              : 1;
 340     uintptr_t allClassesRealized    : 1;
 341     uintptr_t next                  : 62;
 342 #else
 343     uintptr_t isLoaded              : 1;
 344     uintptr_t allClassesRealized    : 1;
 345     uintptr_t next                  : 30;
 346 #endif
 347 } header_info_rw;
 348
 349 struct header_info_rw* getPreoptimizedHeaderRW(const struct header_info *const hdr);
 350
 351 typedef struct header_info {
 352 private:
 353     // Note, this is no longer a pointer, but instead an offset to a pointer
 354     // from this location.
 355     intptr_t mhdr_offset;
 356
 357     // Note, this is no longer a pointer, but instead an offset to a pointer
 358     // from this location.
 359     intptr_t info_offset;
 360
 361     // Do not add fields without editing ObjCModernAbstraction.hpp
 362 public:
 363
 364     header_info_rw *getHeaderInfoRW() {
 365         header_info_rw *preopt =
 366             isPreoptimized() ? getPreoptimizedHeaderRW(this) : nil;
 367         if (preopt) return preopt;
 368         else return &rw_data[0];
 369     }
 370
 371     const headerType *mhdr() const {
 372         return (const headerType *)(((intptr_t)&mhdr_offset) + mhdr_offset);
 373     }
 374
 375     void setmhdr(const headerType *mhdr) {
 376         mhdr_offset = (intptr_t)mhdr - (intptr_t)&mhdr_offset;
 377     }
 378
 379     const objc_image_info *info() const {
 380         return (const objc_image_info *)(((intptr_t)&info_offset) + info_offset);
 381     }
 382
 383     void setinfo(const objc_image_info *info) {
 384         info_offset = (intptr_t)info - (intptr_t)&info_offset;
 385     }
 386
 387     bool isLoaded() {
 388         return getHeaderInfoRW()->getLoaded();
 389     }
 390
 391     void setLoaded(bool v) {
 392         getHeaderInfoRW()->setLoaded(v);
 393     }
 394
 395     bool areAllClassesRealized() {
 396         return getHeaderInfoRW()->getAllClassesRealized();
 397     }
 398
 399     void setAllClassesRealized(bool v) {
 400         getHeaderInfoRW()->setAllClassesRealized(v);
 401     }
 402
 403     header_info *getNext() {
 404         return getHeaderInfoRW()->getNext();
 405     }
 406
 407     void setNext(header_info *v) {
 408         getHeaderInfoRW()->setNext(v);
 409     }
 410
 411     bool isBundle() {
 412         return mhdr()->filetype == MH_BUNDLE;
 413     }
 414
 415     const char *fname() const {
 416         return dyld_image_path_containing_address(mhdr());
 417     }
 418
 419     bool isPreoptimized() const;
 420
 421     bool hasPreoptimizedSelectors() const;
 422
 423     bool hasPreoptimizedClasses() const;
 424
 425     bool hasPreoptimizedProtocols() const;
 426
 427 #if !__OBJC2__
 428     struct old_protocol **proto_refs;
 429     struct objc_module *mod_ptr;
 430     size_t              mod_count;
 431 # if TARGET_OS_WIN32
 432     struct objc_module **modules;
 433     size_t moduleCount;
 434     struct old_protocol **protocols;
 435     size_t protocolCount;
 436     void *imageinfo;
 437     size_t imageinfoBytes;
 438     SEL *selrefs;
 439     size_t selrefCount;
 440     struct objc_class **clsrefs;
 441     size_t clsrefCount;
 442     TCHAR *moduleName;
 443 # endif
 444 #endif
 445
 446 private:
 447     // Images in the shared cache will have an empty array here while those
 448     // allocated at run time will allocate a single entry.
 449     header_info_rw rw_data[];
 450 } header_info;
 451
 452 extern header_info *FirstHeader;
 453 extern header_info *LastHeader;
 454
 455 extern void appendHeader(header_info *hi);
 456 extern void removeHeader(header_info *hi);
 457
 458 extern objc_image_info *_getObjcImageInfo(const headerType *head, size_t *size);
 459 extern bool _hasObjcContents(const header_info *hi);
 460
 461
 462 // Mach-O segment and section names are 16 bytes and may be un-terminated.
 463
 464 static inline bool segnameEquals(const char *lhs, const char *rhs) {
 465     return 0 == strncmp(lhs, rhs, 16);
 466 }
 467
 468 static inline bool segnameStartsWith(const char *segname, const char *prefix) {
 469     return 0 == strncmp(segname, prefix, strlen(prefix));
 470 }
 471
 472 static inline bool sectnameEquals(const char *lhs, const char *rhs) {
 473     return segnameEquals(lhs, rhs);
 474 }
 475
 476 static inline bool sectnameStartsWith(const char *sectname, const char *prefix){
 477     return segnameStartsWith(sectname, prefix);
 478 }
 479
 480
 481 /* selectors */
 482 extern void sel_init(size_t selrefCount);
 483 extern SEL sel_registerNameNoLock(const char *str, bool copy);
 484
 485 extern SEL SEL_cxx_construct;
 486 extern SEL SEL_cxx_destruct;
 487
 488 /* preoptimization */
 489 extern void preopt_init(void);
 490 extern void disableSharedCacheOptimizations(void);
 491 extern bool isPreoptimized(void);
 492 extern bool noMissingWeakSuperclasses(void);
 493 extern header_info *preoptimizedHinfoForHeader(const headerType *mhdr);
 494
 495 extern objc_selopt_t *preoptimizedSelectors(void);
 496
 497 extern bool sharedCacheSupportsProtocolRoots(void);
 498 extern Protocol *getPreoptimizedProtocol(const char *name);
 499 extern Protocol *getSharedCachePreoptimizedProtocol(const char *name);
 500
 501 extern unsigned getPreoptimizedClassUnreasonableCount();
 502 extern Class getPreoptimizedClass(const char *name);
 503 extern Class* copyPreoptimizedClasses(const char *name, int *outCount);
 504
 505 extern Class _calloc_class(size_t size);
 506
 507 /* method lookup */
 508 enum {
 509     LOOKUP_INITIALIZE = 1,
 510     LOOKUP_RESOLVER = 2,
 511     LOOKUP_CACHE = 4,
 512     LOOKUP_NIL = 8,
 513 };
 514 extern IMP lookUpImpOrForward(id obj, SEL, Class cls, int behavior);
 515
 516 static inline IMP
 517 lookUpImpOrNil(id obj, SEL sel, Class cls, int behavior = 0)
 518 {
 519     return lookUpImpOrForward(obj, sel, cls, behavior | LOOKUP_CACHE | LOOKUP_NIL);
 520 }
 521
 522 extern IMP lookupMethodInClassAndLoadCache(Class cls, SEL sel);
 523 extern BOOL class_respondsToSelector_inst(id inst, SEL sel, Class cls);
 524 extern Class class_initialize(Class cls, id inst);
 525
 526 extern bool objcMsgLogEnabled;
 527 extern bool logMessageSend(bool isClassMethod,
 528                     const char *objectsClass,
 529                     const char *implementingClass,
 530                     SEL selector);
 531
 532 /* message dispatcher */
 533
 534 #if !OBJC_OLD_DISPATCH_PROTOTYPES
 535 extern void _objc_msgForward_impcache(void);
 536 #else
 537 extern id _objc_msgForward_impcache(id, SEL, ...);
 538 #endif
 539
 540 /* errors */
 541 extern id(*badAllocHandler)(Class);
 542 extern id _objc_callBadAllocHandler(Class cls) __attribute__((cold, noinline));
 543 extern void __objc_error(id, const char *, ...) __attribute__((cold, format (printf, 2, 3), noreturn));
 544 extern void _objc_inform(const char *fmt, ...) __attribute__((cold, format(printf, 1, 2)));
 545 extern void _objc_inform_on_crash(const char *fmt, ...) __attribute__((cold, format (printf, 1, 2)));
 546 extern void _objc_inform_now_and_on_crash(const char *fmt, ...) __attribute__((cold, format (printf, 1, 2)));
 547 extern void _objc_inform_deprecated(const char *oldname, const char *newname) __attribute__((cold, noinline));
 548 extern void inform_duplicate(const char *name, Class oldCls, Class cls);
 549
 550 /* magic */
 551 extern Class _objc_getFreedObjectClass (void);
 552
 553 /* map table additions */
 554 extern void *NXMapKeyCopyingInsert(NXMapTable *table, const void *key, const void *value);
 555 extern void *NXMapKeyFreeingRemove(NXMapTable *table, const void *key);
 556
 557 /* hash table additions */
 558 extern unsigned _NXHashCapacity(NXHashTable *table);
 559 extern void _NXHashRehashToCapacity(NXHashTable *table, unsigned newCapacity);
 560
 561 /* property attribute parsing */
 562 extern const char *copyPropertyAttributeString(const objc_property_attribute_t *attrs, unsigned int count);
 563 extern objc_property_attribute_t *copyPropertyAttributeList(const char *attrs, unsigned int *outCount);
 564 extern char *copyPropertyAttributeValue(const char *attrs, const char *name);
 565
 566 /* locking */
 567
 568 class monitor_locker_t : nocopy_t {
 569     monitor_t& lock;
 570   public:
 571     monitor_locker_t(monitor_t& newLock) : lock(newLock) { lock.enter(); }
 572     ~monitor_locker_t() { lock.leave(); }
 573 };
 574
 575 class recursive_mutex_locker_t : nocopy_t {
 576     recursive_mutex_t& lock;
 577   public:
 578     recursive_mutex_locker_t(recursive_mutex_t& newLock)
 579         : lock(newLock) { lock.lock(); }
 580     ~recursive_mutex_locker_t() { lock.unlock(); }
 581 };
 582
 583
 584 /* Exceptions */
 585 struct alt_handler_list;
 586 extern void exception_init(void);
 587 extern void _destroyAltHandlerList(struct alt_handler_list *list);
 588
 589 /* Class change notifications (gdb only for now) */
 590 #define OBJC_CLASS_ADDED (1<<0)
 591 #define OBJC_CLASS_REMOVED (1<<1)
 592 #define OBJC_CLASS_IVARS_CHANGED (1<<2)
 593 #define OBJC_CLASS_METHODS_CHANGED (1<<3)
 594 extern void gdb_objc_class_changed(Class cls, unsigned long changes, const char *classname)
 595     __attribute__((noinline));
 596
 597
 598 // Settings from environment variables
 599 #define OPTION(var, env, help) extern bool var;
 600 #include "objc-env.h"
 601 #undef OPTION
 602
 603 extern void environ_init(void);
 604 extern void runtime_init(void);
 605
 606 extern void logReplacedMethod(const char *className, SEL s, bool isMeta, const char *catName, IMP oldImp, IMP newImp);
 607
 608
 609 // objc per-thread storage
 610 typedef struct {
 611     struct _objc_initializing_classes *initializingClasses; // for +initialize
 612     struct SyncCache *syncCache;  // for @synchronize
 613     struct alt_handler_list *handlerList;  // for exception alt handlers
 614     char *printableNames[4];  // temporary demangled names for logging
 615     const char **classNameLookups;  // for objc_getClass() hooks
 616     unsigned classNameLookupsAllocated;
 617     unsigned classNameLookupsUsed;
 618
 619     // If you add new fields here, don't forget to update
 620     // _objc_pthread_destroyspecific()
 621
 622 } _objc_pthread_data;
 623
 624 extern _objc_pthread_data *_objc_fetch_pthread_data(bool create);
 625 extern void tls_init(void);
 626
 627 // encoding.h
 628 extern unsigned int encoding_getNumberOfArguments(const char *typedesc);
 629 extern unsigned int encoding_getSizeOfArguments(const char *typedesc);
 630 extern unsigned int encoding_getArgumentInfo(const char *typedesc, unsigned int arg, const char **type, int *offset);
 631 extern void encoding_getReturnType(const char *t, char *dst, size_t dst_len);
 632 extern char * encoding_copyReturnType(const char *t);
 633 extern void encoding_getArgumentType(const char *t, unsigned int index, char *dst, size_t dst_len);
 634 extern char *encoding_copyArgumentType(const char *t, unsigned int index);
 635
 636 // sync.h
 637 extern void _destroySyncCache(struct SyncCache *cache);
 638
 639 // arr
 640 extern void arr_init(void);
 641 extern id objc_autoreleaseReturnValue(id obj);
 642
 643 // block trampolines
 644 extern void _imp_implementationWithBlock_init(void);
 645 extern IMP _imp_implementationWithBlockNoCopy(id block);
 646
 647 // layout.h
 648 typedef struct {
 649     uint8_t *bits;
 650     size_t bitCount;
 651     size_t bitsAllocated;
 652     bool weak;
 653 } layout_bitmap;
 654 extern layout_bitmap layout_bitmap_create(const unsigned char *layout_string, size_t layoutStringInstanceSize, size_t instanceSize, bool weak);
 655 extern layout_bitmap layout_bitmap_create_empty(size_t instanceSize, bool weak);
 656 extern void layout_bitmap_free(layout_bitmap bits);
 657 extern const unsigned char *layout_string_create(layout_bitmap bits);
 658 extern void layout_bitmap_set_ivar(layout_bitmap bits, const char *type, size_t offset);
 659 extern void layout_bitmap_grow(layout_bitmap *bits, size_t newCount);
 660 extern void layout_bitmap_slide(layout_bitmap *bits, size_t oldPos, size_t newPos);
 661 extern void layout_bitmap_slide_anywhere(layout_bitmap *bits, size_t oldPos, size_t newPos);
 662 extern bool layout_bitmap_splat(layout_bitmap dst, layout_bitmap src,
 663                                 size_t oldSrcInstanceSize);
 664 extern bool layout_bitmap_or(layout_bitmap dst, layout_bitmap src, const char *msg);
 665 extern bool layout_bitmap_clear(layout_bitmap dst, layout_bitmap src, const char *msg);
 666 extern void layout_bitmap_print(layout_bitmap bits);
 667
 668
 669 // fixme runtime
 670 extern bool MultithreadedForkChild;
 671 extern id objc_noop_imp(id self, SEL _cmd);
 672 extern Class look_up_class(const char *aClassName, bool includeUnconnected, bool includeClassHandler);
 673 extern "C" void map_images(unsigned count, const char * const paths[],
 674                            const struct mach_header * const mhdrs[]);
 675 extern void map_images_nolock(unsigned count, const char * const paths[],
 676                               const struct mach_header * const mhdrs[]);
 677 extern void load_images(const char *path, const struct mach_header *mh);
 678 extern void unmap_image(const char *path, const struct mach_header *mh);
 679 extern void unmap_image_nolock(const struct mach_header *mh);
 680 extern void _read_images(header_info **hList, uint32_t hCount, int totalClasses, int unoptimizedTotalClass);
 681 extern void _unload_image(header_info *hi);
 682
 683 extern const header_info *_headerForClass(Class cls);
 684
 685 extern Class _class_remap(Class cls);
 686 extern Ivar _class_getVariable(Class cls, const char *name);
 687
 688 extern unsigned _class_createInstancesFromZone(Class cls, size_t extraBytes, void *zone, id *results, unsigned num_requested);
 689
 690 extern const char *_category_getName(Category cat);
 691 extern const char *_category_getClassName(Category cat);
 692 extern Class _category_getClass(Category cat);
 693 extern IMP _category_getLoadMethod(Category cat);
 694
 695 enum {
 696     OBJECT_CONSTRUCT_NONE = 0,
 697     OBJECT_CONSTRUCT_FREE_ONFAILURE = 1,
 698     OBJECT_CONSTRUCT_CALL_BADALLOC = 2,
 699 };
 700 extern id object_cxxConstructFromClass(id obj, Class cls, int flags);
 701 extern void object_cxxDestruct(id obj);
 702
 703 extern void fixupCopiedIvars(id newObject, id oldObject);
 704 extern Class _class_getClassForIvar(Class cls, Ivar ivar);
 705
 706
 707 #define OBJC_WARN_DEPRECATED \
 708     do { \
 709         static int warned = 0; \
 710         if (!warned) { \
 711             warned = 1; \
 712             _objc_inform_deprecated(__FUNCTION__, NULL); \
 713         } \
 714     } while (0) \
 715
 716 __END_DECLS
 717
 718
 719 #ifndef STATIC_ASSERT
 720 #   define STATIC_ASSERT(x) _STATIC_ASSERT2(x, __LINE__)
 721 #   define _STATIC_ASSERT2(x, line) _STATIC_ASSERT3(x, line)
 722 #   define _STATIC_ASSERT3(x, line)                                     \
 723         typedef struct {                                                \
 724             int _static_assert[(x) ? 0 : -1];                           \
 725         } _static_assert_ ## line __attribute__((unavailable))
 726 #endif
 727
 728 #define countof(arr) (sizeof(arr) / sizeof((arr)[0]))
 729
 730
 731 static __inline uint32_t _objc_strhash(const char *s) {
 732     uint32_t hash = 0;
 733     for (;;) {
 734     int a = *s++;
 735     if (0 == a) break;
 736     hash += (hash << 8) + a;
 737     }
 738     return hash;
 739 }
 740
 741 #if __cplusplus
 742
 743 template <typename T>
 744 static inline T log2u(T x) {
 745     return (x<2) ? 0 : log2u(x>>1)+1;
 746 }
 747
 748 template <typename T>
 749 static inline T exp2u(T x) {
 750     return (1 << x);
 751 }
 752
 753 template <typename T>
 754 static T exp2m1u(T x) {
 755     return (1 << x) - 1;
 756 }
 757
 758 #endif
 759
 760 // Misalignment-safe integer types
 761 __attribute__((aligned(1))) typedef uintptr_t unaligned_uintptr_t;
 762 __attribute__((aligned(1))) typedef  intptr_t unaligned_intptr_t;
 763 __attribute__((aligned(1))) typedef  uint64_t unaligned_uint64_t;
 764 __attribute__((aligned(1))) typedef   int64_t unaligned_int64_t;
 765 __attribute__((aligned(1))) typedef  uint32_t unaligned_uint32_t;
 766 __attribute__((aligned(1))) typedef   int32_t unaligned_int32_t;
 767 __attribute__((aligned(1))) typedef  uint16_t unaligned_uint16_t;
 768 __attribute__((aligned(1))) typedef   int16_t unaligned_int16_t;
 769
 770
 771 // Global operator new and delete. We must not use any app overrides.
 772 // This ALSO REQUIRES each of these be in libobjc's unexported symbol list.
 773 #if __cplusplus
 774 #pragma clang diagnostic push
 775 #pragma clang diagnostic ignored "-Winline-new-delete"
 776 #include <new>
 777 inline void* operator new(std::size_t size) throw (std::bad_alloc) { return malloc(size); }
 778 inline void* operator new[](std::size_t size) throw (std::bad_alloc) { return malloc(size); }
 779 inline void* operator new(std::size_t size, const std::nothrow_t&) throw() { return malloc(size); }
 780 inline void* operator new[](std::size_t size, const std::nothrow_t&) throw() { return malloc(size); }
 781 inline void operator delete(void* p) throw() { free(p); }
 782 inline void operator delete[](void* p) throw() { free(p); }
 783 inline void operator delete(void* p, const std::nothrow_t&) throw() { free(p); }
 784 inline void operator delete[](void* p, const std::nothrow_t&) throw() { free(p); }
 785 #pragma clang diagnostic pop
 786 #endif
 787
 788
 789 class TimeLogger {
 790     uint64_t mStart;
 791     bool mRecord;
 792  public:
 793     TimeLogger(bool record = true)
 794      : mStart(nanoseconds())
 795      , mRecord(record)
 796     { }
 797
 798     void log(const char *msg) {
 799         if (mRecord) {
 800             uint64_t end = nanoseconds();
 801             _objc_inform("%.2f ms: %s", (end - mStart) / 1000000.0, msg);
 802             mStart = nanoseconds();
 803         }
 804     }
 805 };
 806
 807 enum { CacheLineSize = 64 };
 808
 809 // StripedMap<T> is a map of void* -> T, sized appropriately
 810 // for cache-friendly lock striping.
 811 // For example, this may be used as StripedMap<spinlock_t>
 812 // or as StripedMap<SomeStruct> where SomeStruct stores a spin lock.
 813 template<typename T>
 814 class StripedMap {
 815 #if TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
 816     enum { StripeCount = 8 };
 817 #else
 818     enum { StripeCount = 64 };
 819 #endif
 820
 821     struct PaddedT {
 822         T value alignas(CacheLineSize);
 823     };
 824
 825     PaddedT array[StripeCount];
 826
 827     static unsigned int indexForPointer(const void *p) {
 828         uintptr_t addr = reinterpret_cast<uintptr_t>(p);
 829         return ((addr >> 4) ^ (addr >> 9)) % StripeCount;
 830     }
 831
 832  public:
 833     T& operator[] (const void *p) {
 834         return array[indexForPointer(p)].value;
 835     }
 836     const T& operator[] (const void *p) const {
 837         return const_cast<StripedMap<T>>(this)[p];
 838     }
 839
 840     // Shortcuts for StripedMaps of locks.
 841     void lockAll() {
 842         for (unsigned int i = 0; i < StripeCount; i++) {
 843             array[i].value.lock();
 844         }
 845     }
 846
 847     void unlockAll() {
 848         for (unsigned int i = 0; i < StripeCount; i++) {
 849             array[i].value.unlock();
 850         }
 851     }
 852
 853     void forceResetAll() {
 854         for (unsigned int i = 0; i < StripeCount; i++) {
 855             array[i].value.forceReset();
 856         }
 857     }
 858
 859     void defineLockOrder() {
 860         for (unsigned int i = 1; i < StripeCount; i++) {
 861             lockdebug_lock_precedes_lock(&array[i-1].value, &array[i].value);
 862         }
 863     }
 864
 865     void precedeLock(const void *newlock) {
 866         // assumes defineLockOrder is also called
 867         lockdebug_lock_precedes_lock(&array[StripeCount-1].value, newlock);
 868     }
 869
 870     void succeedLock(const void *oldlock) {
 871         // assumes defineLockOrder is also called
 872         lockdebug_lock_precedes_lock(oldlock, &array[0].value);
 873     }
 874
 875     const void *getLock(int i) {
 876         if (i < StripeCount) return &array[i].value;
 877         else return nil;
 878     }
 879
 880 #if DEBUG
 881     StripedMap() {
 882         // Verify alignment expectations.
 883         uintptr_t base = (uintptr_t)&array[0].value;
 884         uintptr_t delta = (uintptr_t)&array[1].value - base;
 885         ASSERT(delta % CacheLineSize == 0);
 886         ASSERT(base % CacheLineSize == 0);
 887     }
 888 #else
 889     constexpr StripedMap() {}
 890 #endif
 891 };
 892
 893
 894 // DisguisedPtr<T> acts like pointer type T*, except the
 895 // stored value is disguised to hide it from tools like `leaks`.
 896 // nil is disguised as itself so zero-filled memory works as expected,
 897 // which means 0x80..00 is also disguised as itself but we don't care.
 898 // Note that weak_entry_t knows about this encoding.
 899 template <typename T>
 900 class DisguisedPtr {
 901     uintptr_t value;
 902
 903     static uintptr_t disguise(T* ptr) {
 904         return -(uintptr_t)ptr;
 905     }
 906
 907     static T* undisguise(uintptr_t val) {
 908         return (T*)-val;
 909     }
 910
 911  public:
 912     DisguisedPtr() { }
 913     DisguisedPtr(T* ptr)
 914         : value(disguise(ptr)) { }
 915     DisguisedPtr(const DisguisedPtr<T>& ptr)
 916         : value(ptr.value) { }
 917
 918     DisguisedPtr<T>& operator = (T* rhs) {
 919         value = disguise(rhs);
 920         return *this;
 921     }
 922     DisguisedPtr<T>& operator = (const DisguisedPtr<T>& rhs) {
 923         value = rhs.value;
 924         return *this;
 925     }
 926
 927     operator T* () const {
 928         return undisguise(value);
 929     }
 930     T* operator -> () const {
 931         return undisguise(value);
 932     }
 933     T& operator * () const {
 934         return *undisguise(value);
 935     }
 936     T& operator [] (size_t i) const {
 937         return undisguise(value)[i];
 938     }
 939
 940     // pointer arithmetic operators omitted
 941     // because we don't currently use them anywhere
 942 };
 943
 944 // fixme type id is weird and not identical to objc_object*
 945 static inline bool operator == (DisguisedPtr<objc_object> lhs, id rhs) {
 946     return lhs == (objc_object *)rhs;
 947 }
 948 static inline bool operator != (DisguisedPtr<objc_object> lhs, id rhs) {
 949     return lhs != (objc_object *)rhs;
 950 }
 951
 952
 953 // Storage for a thread-safe chained hook function.
 954 // get() returns the value for calling.
 955 // set() installs a new function and returns the old one for chaining.
 956 // More precisely, set() writes the old value to a variable supplied by
 957 // the caller. get() and set() use appropriate barriers so that the
 958 // old value is safely written to the variable before the new value is
 959 // called to use it.
 960 //
 961 // T1: store to old variable; store-release to hook variable
 962 // T2: load-acquire from hook variable; call it; called hook loads old variable
 963
 964 template <typename Fn>
 965 class ChainedHookFunction {
 966     std::atomic<Fn> hook{nil};
 967
 968 public:
 969     ChainedHookFunction(Fn f) : hook{f} { };
 970
 971     Fn get() {
 972         return hook.load(std::memory_order_acquire);
 973     }
 974
 975     void set(Fn newValue, Fn *oldVariable)
 976     {
 977         Fn oldValue = hook.load(std::memory_order_relaxed);
 978         do {
 979             *oldVariable = oldValue;
 980         } while (!hook.compare_exchange_weak(oldValue, newValue,
 981                                              std::memory_order_release,
 982                                              std::memory_order_relaxed));
 983     }
 984 };
 985
 986
 987 // A small vector for use as a global variable. Only supports appending and
 988 // iteration. Stores a single element inline, and multiple elements in a heap
 989 // allocation. There is no attempt to amortize reallocation cost; this is
 990 // intended to be used in situation where zero or one element is common, two
 991 // might happen, and three or more is very rare.
 992 //
 993 // This does not clean up its allocation, and thus cannot be used as a local
 994 // variable or member of something with limited lifetime.
 995
 996 template <typename T, unsigned InlineCount>
 997 class GlobalSmallVector {
 998     static_assert(std::is_pod<T>::value, "SmallVector requires POD types");
 999
1000 protected:
1001     unsigned count{0};
1002     union {
1003         T inlineElements[InlineCount];
1004         T *elements;
1005     };
1006
1007 public:
1008     void append(const T &val) {
1009         if (count < InlineCount) {
1010             // We have space. Store the new value inline.
1011             inlineElements[count] = val;
1012         } else if (count == InlineCount) {
1013             // Inline storage is full. Switch to a heap allocation.
1014             T *newElements = (T *)malloc((count + 1) * sizeof(T));
1015             memcpy(newElements, inlineElements, count * sizeof(T));
1016             newElements[count] = val;
1017             elements = newElements;
1018         } else {
1019             // Resize the heap allocation and append.
1020             elements = (T *)realloc(elements, (count + 1) * sizeof(T));
1021             elements[count] = val;
1022         }
1023         count++;
1024     }
1025
1026     const T *begin() const {
1027         return count <= InlineCount ? inlineElements : elements;
1028     }
1029
1030     const T *end() const {
1031         return begin() + count;
1032     }
1033 };
1034
1035 // A small vector that cleans up its internal memory allocation when destroyed.
1036 template <typename T, unsigned InlineCount>
1037 class SmallVector: public GlobalSmallVector<T, InlineCount> {
1038 public:
1039     ~SmallVector() {
1040         if (this->count > InlineCount)
1041             free(this->elements);
1042     }
1043
1044     template <unsigned OtherCount>
1045     void initFrom(const GlobalSmallVector<T, OtherCount> &other) {
1046         ASSERT(this->count == 0);
1047         this->count = (unsigned)(other.end() - other.begin());
1048         if (this->count > InlineCount) {
1049             this->elements = (T *)memdup(other.begin(), this->count * sizeof(T));
1050         } else {
1051             memcpy(this->inlineElements, other.begin(), this->count * sizeof(T));
1052         }
1053     }
1054 };
1055
1056 // Pointer hash function.
1057 // This is not a terrific hash, but it is fast
1058 // and not outrageously flawed for our purposes.
1059
1060 // Based on principles from http://locklessinc.com/articles/fast_hash/
1061 // and evaluation ideas from http://floodyberry.com/noncryptohashzoo/
1062 #if __LP64__
1063 static inline uint32_t ptr_hash(uint64_t key)
1064 {
1065     key ^= key >> 4;
1066     key *= 0x8a970be7488fda55;
1067     key ^= __builtin_bswap64(key);
1068     return (uint32_t)key;
1069 }
1070 #else
1071 static inline uint32_t ptr_hash(uint32_t key)
1072 {
1073     key ^= key >> 4;
1074     key *= 0x5052acdb;
1075     key ^= __builtin_bswap32(key);
1076     return key;
1077 }
1078 #endif
1079
1080 /*
1081   Higher-quality hash function. This is measurably slower in some workloads.
1082 #if __LP64__
1083  uint32_t ptr_hash(uint64_t key)
1084 {
1085     key -= __builtin_bswap64(key);
1086     key *= 0x8a970be7488fda55;
1087     key ^= __builtin_bswap64(key);
1088     key *= 0x8a970be7488fda55;
1089     key ^= __builtin_bswap64(key);
1090     return (uint32_t)key;
1091 }
1092 #else
1093 static uint32_t ptr_hash(uint32_t key)
1094 {
1095     key -= __builtin_bswap32(key);
1096     key *= 0x5052acdb;
1097     key ^= __builtin_bswap32(key);
1098     key *= 0x5052acdb;
1099     key ^= __builtin_bswap32(key);
1100     return key;
1101 }
1102 #endif
1103 */
1104
1105
1106
1107 // Lock declarations
1108 #include "objc-locks.h"
1109
1110 // Inlined parts of objc_object's implementation
1111 #include "objc-object.h"
1112
1113 #endif /* _OBJC_PRIVATE_H_ */
1114