runtime/objc-abi.h

   1 /*
   2  * Copyright (c) 2009 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
  25 #ifndef _OBJC_ABI_H
  26 #define _OBJC_ABI_H
  27
  28 /*
  29  * WARNING  DANGER  HAZARD  BEWARE  EEK
  30  *
  31  * Everything in this file is for Apple Internal use only.
  32  * These will change in arbitrary OS updates and in unpredictable ways.
  33  * When your program breaks, you get to keep both pieces.
  34  */
  35
  36 /*
  37  * objc-abi.h: Declarations for functions used by compiler codegen.
  38  */
  39
  40 #include <malloc/malloc.h>
  41 #include <TargetConditionals.h>
  42 #include <objc/objc.h>
  43 #include <objc/runtime.h>
  44 #include <objc/message.h>
  45
  46 /* Linker metadata symbols */
  47
  48 // NSObject was in Foundation/CF on macOS < 10.8.
  49 #if TARGET_OS_OSX && (__x86_64__ || __i386__)
  50 #if __OBJC2__
  51
  52 OBJC_EXPORT const char __objc_nsobject_class_10_5
  53     __asm__("$ld$hide$os10.5$_OBJC_CLASS_$_NSObject");
  54 OBJC_EXPORT const char __objc_nsobject_class_10_6
  55     __asm__("$ld$hide$os10.6$_OBJC_CLASS_$_NSObject");
  56 OBJC_EXPORT const char __objc_nsobject_class_10_7
  57     __asm__("$ld$hide$os10.7$_OBJC_CLASS_$_NSObject");
  58
  59 OBJC_EXPORT const char __objc_nsobject_metaclass_10_5
  60     __asm__("$ld$hide$os10.5$_OBJC_METACLASS_$_NSObject");
  61 OBJC_EXPORT const char __objc_nsobject_metaclass_10_6
  62     __asm__("$ld$hide$os10.6$_OBJC_METACLASS_$_NSObject");
  63 OBJC_EXPORT const char __objc_nsobject_metaclass_10_7
  64     __asm__("$ld$hide$os10.7$_OBJC_METACLASS_$_NSObject");
  65
  66 OBJC_EXPORT const char __objc_nsobject_isa_10_5
  67     __asm__("$ld$hide$os10.5$_OBJC_IVAR_$_NSObject.isa");
  68 OBJC_EXPORT const char __objc_nsobject_isa_10_6
  69     __asm__("$ld$hide$os10.6$_OBJC_IVAR_$_NSObject.isa");
  70 OBJC_EXPORT const char __objc_nsobject_isa_10_7
  71     __asm__("$ld$hide$os10.7$_OBJC_IVAR_$_NSObject.isa");
  72
  73 #else
  74
  75 OBJC_EXPORT const char __objc_nsobject_class_10_5
  76     __asm__("$ld$hide$os10.5$.objc_class_name_NSObject");
  77 OBJC_EXPORT const char __objc_nsobject_class_10_6
  78     __asm__("$ld$hide$os10.6$.objc_class_name_NSObject");
  79 OBJC_EXPORT const char __objc_nsobject_class_10_7
  80     __asm__("$ld$hide$os10.7$.objc_class_name_NSObject");
  81
  82 #endif
  83 #endif
  84
  85 /* Runtime startup. */
  86
  87 // Old static initializer. Used by old crt1.o and old bug workarounds.
  88 OBJC_EXPORT void
  89 _objcInit(void)
  90     OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
  91
  92 /* Images */
  93
  94 // Description of an Objective-C image.
  95 // __DATA,__objc_imageinfo stores one of these.
  96 typedef struct objc_image_info {
  97     uint32_t version; // currently 0
  98     uint32_t flags;
  99
 100 #if __cplusplus >= 201103L
 101   private:
 102     enum : uint32_t {
 103         // 1 byte assorted flags
 104         IsReplacement       = 1<<0,  // used for Fix&Continue, now ignored
 105         SupportsGC          = 1<<1,  // image supports GC
 106         RequiresGC          = 1<<2,  // image requires GC
 107         OptimizedByDyld     = 1<<3,  // image is from an optimized shared cache
 108         CorrectedSynthesize = 1<<4,  // used for an old workaround, now ignored
 109         IsSimulated         = 1<<5,  // image compiled for a simulator platform
 110         HasCategoryClassProperties  = 1<<6,  // class properties in category_t
 111         OptimizedByDyldClosure = 1 << 7, // dyld (not the shared cache) optimized this.
 112
 113         // 1 byte Swift unstable ABI version number
 114         SwiftUnstableVersionMaskShift = 8,
 115         SwiftUnstableVersionMask = 0xff << SwiftUnstableVersionMaskShift,
 116
 117         // 2 byte Swift stable ABI version number
 118         SwiftStableVersionMaskShift = 16,
 119         SwiftStableVersionMask = 0xffffUL << SwiftStableVersionMaskShift
 120     };
 121   public:
 122     enum : uint32_t {
 123         // Values for SwiftUnstableVersion
 124         // All stable ABIs store SwiftVersion5 here.
 125         SwiftVersion1   = 1,
 126         SwiftVersion1_2 = 2,
 127         SwiftVersion2   = 3,
 128         SwiftVersion3   = 4,
 129         SwiftVersion4   = 5,
 130         SwiftVersion4_1 = 6,
 131         SwiftVersion4_2 = 6,  // [sic]
 132         SwiftVersion5   = 7
 133     };
 134
 135   public:
 136     bool isReplacement()   const { return flags & IsReplacement; }
 137     bool supportsGC()      const { return flags & SupportsGC; }
 138     bool requiresGC()      const { return flags & RequiresGC; }
 139     bool optimizedByDyld() const { return flags & OptimizedByDyld; }
 140     bool hasCategoryClassProperties() const { return flags & HasCategoryClassProperties; }
 141     bool optimizedByDyldClosure() const { return flags & OptimizedByDyldClosure; }
 142     bool containsSwift()   const { return (flags & SwiftUnstableVersionMask) != 0; }
 143     uint32_t swiftUnstableVersion() const { return (flags & SwiftUnstableVersionMask) >> SwiftUnstableVersionMaskShift; }
 144 #endif
 145 } objc_image_info;
 146
 147 /*
 148 IsReplacement:
 149    Once used for Fix&Continue in old OS X object files (not final linked images)
 150    Not currently used.
 151
 152 SupportsGC:
 153    App: GC is required. Framework: GC is supported but not required.
 154
 155 RequiresGC:
 156    Framework: GC is required.
 157
 158 OptimizedByDyld:
 159    Assorted metadata precooked in the dyld shared cache.
 160    Never set for images outside the shared cache file itself.
 161
 162 CorrectedSynthesize:
 163    Once used on old iOS to mark images that did not have a particular
 164    miscompile. Not used by the runtime.
 165
 166 IsSimulated:
 167    Image was compiled for a simulator platform. Not used by the runtime.
 168
 169 HasClassProperties:
 170    New ABI: category_t.classProperties fields are present.
 171    Old ABI: Set by some compilers. Not used by the runtime.
 172 */
 173
 174 // Description of an expected duplicate class name.
 175 // __DATA,__objc_dupclass stores one of these. Only the main image is
 176 // consulted for these purposes.
 177 typedef struct _objc_duplicate_class {
 178     uint32_t version;
 179     uint32_t flags;
 180     const char name[64];
 181 } objc_duplicate_class;
 182 #define OBJC_HAS_DUPLICATE_CLASS 1
 183
 184 /* Properties */
 185
 186 // Read or write an object property. Not all object properties use these.
 187 OBJC_EXPORT id _Nullable
 188 objc_getProperty(id _Nullable self, SEL _Nonnull _cmd,
 189                  ptrdiff_t offset, BOOL atomic)
 190     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 191
 192 OBJC_EXPORT void
 193 objc_setProperty(id _Nullable self, SEL _Nonnull _cmd, ptrdiff_t offset,
 194                  id _Nullable newValue, BOOL atomic, signed char shouldCopy)
 195     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 196
 197 OBJC_EXPORT void
 198 objc_setProperty_atomic(id _Nullable self, SEL _Nonnull _cmd,
 199                         id _Nullable newValue, ptrdiff_t offset)
 200     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 201
 202 OBJC_EXPORT void
 203 objc_setProperty_nonatomic(id _Nullable self, SEL _Nonnull _cmd,
 204                            id _Nullable newValue, ptrdiff_t offset)
 205     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 206
 207 OBJC_EXPORT void
 208 objc_setProperty_atomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 209                              id _Nullable newValue, ptrdiff_t offset)
 210     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 211
 212 OBJC_EXPORT void
 213 objc_setProperty_nonatomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 214                                 id _Nullable newValue, ptrdiff_t offset)
 215     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 216
 217
 218 // Read or write a non-object property. Not all uses are C structs,
 219 // and not all C struct properties use this.
 220 OBJC_EXPORT void
 221 objc_copyStruct(void * _Nonnull dest, const void * _Nonnull src,
 222                 ptrdiff_t size, BOOL atomic, BOOL hasStrong)
 223     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 224
 225 // Perform a copy of a C++ object using striped locks. Used by non-POD C++ typed atomic properties.
 226 OBJC_EXPORT void
 227 objc_copyCppObjectAtomic(void * _Nonnull dest, const void * _Nonnull src,
 228                          void (* _Nonnull copyHelper)
 229                            (void * _Nonnull dest, const void * _Nonnull source))
 230     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 231
 232 /* Classes. */
 233 #if __OBJC2__
 234 OBJC_EXPORT IMP _Nonnull _objc_empty_vtable
 235     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 236 #endif
 237 OBJC_EXPORT struct objc_cache _objc_empty_cache
 238     OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
 239
 240
 241 /* Messages */
 242
 243 #if __OBJC2__
 244 // objc_msgSendSuper2() takes the current search class, not its superclass.
 245 OBJC_EXPORT id _Nullable
 246 objc_msgSendSuper2(struct objc_super * _Nonnull super, SEL _Nonnull op, ...)
 247     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0);
 248
 249 OBJC_EXPORT void
 250 objc_msgSendSuper2_stret(struct objc_super * _Nonnull super,
 251                          SEL _Nonnull op,...)
 252     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0)
 253     OBJC_ARM64_UNAVAILABLE;
 254
 255 // objc_msgSend_noarg() may be faster for methods with no additional arguments.
 256 OBJC_EXPORT id _Nullable
 257 objc_msgSend_noarg(id _Nullable self, SEL _Nonnull _cmd)
 258     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 259 #endif
 260
 261 #if __OBJC2__
 262 // Debug messengers. Messengers used by the compiler have a debug flavor that
 263 // may perform extra sanity checking.
 264 // Old objc_msgSendSuper() does not have a debug version; this is OBJC2 only.
 265 // *_fixup() do not have debug versions; use non-fixup only for debug mode.
 266 OBJC_EXPORT id _Nullable
 267 objc_msgSend_debug(id _Nullable self, SEL _Nonnull op, ...)
 268     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 269
 270 OBJC_EXPORT id _Nullable
 271 objc_msgSendSuper2_debug(struct objc_super * _Nonnull super,
 272                          SEL _Nonnull op, ...)
 273     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 274
 275 OBJC_EXPORT void
 276 objc_msgSend_stret_debug(id _Nullable self, SEL _Nonnull op, ...)
 277     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 278     OBJC_ARM64_UNAVAILABLE;
 279
 280 OBJC_EXPORT void
 281 objc_msgSendSuper2_stret_debug(struct objc_super * _Nonnull super,
 282                                SEL _Nonnull op,...)
 283     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 284     OBJC_ARM64_UNAVAILABLE;
 285
 286 # if defined(__i386__)
 287 OBJC_EXPORT double
 288 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 289     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 290 # elif defined(__x86_64__)
 291 OBJC_EXPORT long double
 292 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 293     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 294 #  if __STDC_VERSION__ >= 199901L
 295 OBJC_EXPORT _Complex long double
 296 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 297     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 298 #  else
 299 OBJC_EXPORT void
 300 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 301     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 302 #  endif
 303 # endif
 304
 305 #endif
 306
 307 #if __OBJC2__
 308 // Lookup messengers.
 309 // These are not callable C functions. Do not call them directly.
 310 // The caller should set the method parameters, call objc_msgLookup(),
 311 // then immediately call the returned IMP.
 312 //
 313 // Generic ABI:
 314 // - Callee-saved registers are preserved.
 315 // - Receiver and selector registers may be modified. These values must
 316 //   be passed to the called IMP. Other parameter registers are preserved.
 317 // - Caller-saved non-parameter registers are not preserved. Some of
 318 //   these registers are used to pass data from objc_msgLookup() to
 319 //   the called IMP and must not be disturbed by the caller.
 320 // - Red zone is not preserved.
 321 // See each architecture's implementation for details.
 322
 323 OBJC_EXPORT void
 324 objc_msgLookup(void)
 325     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 326
 327 OBJC_EXPORT void
 328 objc_msgLookupSuper2(void)
 329     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 330
 331 OBJC_EXPORT void
 332 objc_msgLookup_stret(void)
 333     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 334     OBJC_ARM64_UNAVAILABLE;
 335
 336 OBJC_EXPORT void
 337 objc_msgLookupSuper2_stret(void)
 338     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 339     OBJC_ARM64_UNAVAILABLE;
 340
 341 # if defined(__i386__)
 342 OBJC_EXPORT void
 343 objc_msgLookup_fpret(void)
 344     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 345
 346 # elif defined(__x86_64__)
 347 OBJC_EXPORT void
 348 objc_msgLookup_fpret(void)
 349     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 350
 351 OBJC_EXPORT void
 352 objc_msgLookup_fp2ret(void)
 353     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 354 # endif
 355
 356 #endif
 357
 358 #if (TARGET_OS_OSX || TARGET_OS_SIMULATOR)  &&  defined(__x86_64__)
 359 // objc_msgSend_fixup() was used for vtable-dispatchable call sites.
 360 // The symbols remain exported on macOS for binary compatibility.
 361 // The symbols can probably be removed from iOS simulator but we haven't tried.
 362 OBJC_EXPORT void
 363 objc_msgSend_fixup(void)
 364     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 365
 366 OBJC_EXPORT void
 367 objc_msgSend_stret_fixup(void)
 368     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 369
 370 OBJC_EXPORT void
 371 objc_msgSendSuper2_fixup(void)
 372     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 373
 374 OBJC_EXPORT void
 375 objc_msgSendSuper2_stret_fixup(void)
 376     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 377
 378 OBJC_EXPORT void
 379 objc_msgSend_fpret_fixup(void)
 380     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 381
 382 OBJC_EXPORT void
 383 objc_msgSend_fp2ret_fixup(void)
 384     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 385 #endif
 386
 387 /* C++-compatible exception handling. */
 388 #if __OBJC2__
 389
 390 // Vtable for C++ exception typeinfo for Objective-C types.
 391 OBJC_EXPORT const void * _Nullable objc_ehtype_vtable[]
 392     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 393
 394 // C++ exception typeinfo for type `id`.
 395 OBJC_EXPORT struct objc_typeinfo OBJC_EHTYPE_id
 396     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 397
 398 // Exception personality function for Objective-C and Objective-C++ code.
 399 struct _Unwind_Exception;
 400 struct _Unwind_Context;
 401 OBJC_EXPORT int
 402 __objc_personality_v0(int version,
 403                       int actions,
 404                       uint64_t exceptionClass,
 405                       struct _Unwind_Exception * _Nonnull exceptionObject,
 406                       struct _Unwind_Context * _Nonnull context)
 407     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 408
 409 #endif
 410
 411 /* ARC */
 412
 413 OBJC_EXPORT id _Nullable
 414 objc_retainBlock(id _Nullable)
 415     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 416
 417
 418 /* Non-pointer isa */
 419
 420 #if __OBJC2__
 421
 422 // Extract class pointer from an isa field.
 423
 424 #if TARGET_OS_SIMULATOR && !TARGET_OS_MACCATALYST && !__arm64__
 425     // No simulators use nonpointer isa yet.
 426
 427 #elif __LP64__
 428 #   define OBJC_HAVE_NONPOINTER_ISA 1
 429 #   define OBJC_HAVE_PACKED_NONPOINTER_ISA 1
 430
 431 // Packed-isa version. This one is used directly by Swift code.
 432 // (Class)(isa & (uintptr_t)&objc_absolute_packed_isa_class_mask) == class ptr
 433 OBJC_EXPORT const struct { char c; } objc_absolute_packed_isa_class_mask
 434     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 435
 436 #elif (__ARM_ARCH_7K__ >= 2  ||  (__arm64__ && !__LP64__))
 437 #   define OBJC_HAVE_NONPOINTER_ISA 1
 438 #   define OBJC_HAVE_INDEXED_NONPOINTER_ISA 1
 439
 440 // Indexed-isa version.
 441 // if (isa & (uintptr_t)&objc_absolute_indexed_isa_magic_mask == (uintptr_t)&objc_absolute_indexed_isa_magic_value) {
 442 //     uintptr_t index = (isa & (uintptr_t)&objc_absolute_indexed_isa_index_mask) >> (uintptr_t)&objc_absolute_indexed_isa_index_shift;
 443 //     cls = objc_indexed_classes[index];
 444 // } else
 445 //     cls = (Class)isa;
 446 // }
 447 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_mask
 448     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 449 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_value
 450     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 451 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_mask
 452     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 453 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_shift
 454     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 455
 456 #endif
 457
 458 #endif
 459
 460
 461 /* Object class */
 462
 463 // This symbol might be required for binary compatibility, so we
 464 // declare it here where TAPI will see it.
 465 #if __OBJC__  &&  __OBJC2__
 466 #pragma clang diagnostic push
 467 #pragma clang diagnostic ignored "-Wobjc-interface-ivars"
 468 #if !defined(OBJC_DECLARE_SYMBOLS)
 469 __OSX_AVAILABLE(10.0)
 470 __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 471 __WATCHOS_UNAVAILABLE
 472 #   ifndef __APPLE_BLEACH_SDK__
 473 __BRIDGEOS_UNAVAILABLE
 474 #   endif
 475 #endif
 476 OBJC_ROOT_CLASS
 477 @interface Object {
 478     Class isa;
 479 }
 480 @end
 481 #pragma clang diagnostic pop
 482 #endif
 483
 484
 485 // _OBJC_ABI_H
 486 #endif