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
  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
 175 /* Properties */
 176
 177 // Read or write an object property. Not all object properties use these.
 178 OBJC_EXPORT id _Nullable
 179 objc_getProperty(id _Nullable self, SEL _Nonnull _cmd,
 180                  ptrdiff_t offset, BOOL atomic)
 181     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 182
 183 OBJC_EXPORT void
 184 objc_setProperty(id _Nullable self, SEL _Nonnull _cmd, ptrdiff_t offset,
 185                  id _Nullable newValue, BOOL atomic, signed char shouldCopy)
 186     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 187
 188 OBJC_EXPORT void
 189 objc_setProperty_atomic(id _Nullable self, SEL _Nonnull _cmd,
 190                         id _Nullable newValue, ptrdiff_t offset)
 191     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 192
 193 OBJC_EXPORT void
 194 objc_setProperty_nonatomic(id _Nullable self, SEL _Nonnull _cmd,
 195                            id _Nullable newValue, ptrdiff_t offset)
 196     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 197
 198 OBJC_EXPORT void
 199 objc_setProperty_atomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 200                              id _Nullable newValue, ptrdiff_t offset)
 201     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 202
 203 OBJC_EXPORT void
 204 objc_setProperty_nonatomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 205                                 id _Nullable newValue, ptrdiff_t offset)
 206     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 207
 208
 209 // Read or write a non-object property. Not all uses are C structs,
 210 // and not all C struct properties use this.
 211 OBJC_EXPORT void
 212 objc_copyStruct(void * _Nonnull dest, const void * _Nonnull src,
 213                 ptrdiff_t size, BOOL atomic, BOOL hasStrong)
 214     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 215
 216 // Perform a copy of a C++ object using striped locks. Used by non-POD C++ typed atomic properties.
 217 OBJC_EXPORT void
 218 objc_copyCppObjectAtomic(void * _Nonnull dest, const void * _Nonnull src,
 219                          void (* _Nonnull copyHelper)
 220                            (void * _Nonnull dest, const void * _Nonnull source))
 221     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 222
 223 /* Classes. */
 224 #if __OBJC2__
 225 OBJC_EXPORT IMP _Nonnull _objc_empty_vtable
 226     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 227 #endif
 228 OBJC_EXPORT struct objc_cache _objc_empty_cache
 229     OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
 230
 231
 232 /* Messages */
 233
 234 #if __OBJC2__
 235 // objc_msgSendSuper2() takes the current search class, not its superclass.
 236 OBJC_EXPORT id _Nullable
 237 objc_msgSendSuper2(struct objc_super * _Nonnull super, SEL _Nonnull op, ...)
 238     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0);
 239
 240 OBJC_EXPORT void
 241 objc_msgSendSuper2_stret(struct objc_super * _Nonnull super,
 242                          SEL _Nonnull op,...)
 243     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0)
 244     OBJC_ARM64_UNAVAILABLE;
 245
 246 // objc_msgSend_noarg() may be faster for methods with no additional arguments.
 247 OBJC_EXPORT id _Nullable
 248 objc_msgSend_noarg(id _Nullable self, SEL _Nonnull _cmd)
 249     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 250 #endif
 251
 252 #if __OBJC2__
 253 // Debug messengers. Messengers used by the compiler have a debug flavor that
 254 // may perform extra sanity checking.
 255 // Old objc_msgSendSuper() does not have a debug version; this is OBJC2 only.
 256 // *_fixup() do not have debug versions; use non-fixup only for debug mode.
 257 OBJC_EXPORT id _Nullable
 258 objc_msgSend_debug(id _Nullable self, SEL _Nonnull op, ...)
 259     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 260
 261 OBJC_EXPORT id _Nullable
 262 objc_msgSendSuper2_debug(struct objc_super * _Nonnull super,
 263                          SEL _Nonnull op, ...)
 264     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 265
 266 OBJC_EXPORT void
 267 objc_msgSend_stret_debug(id _Nullable self, SEL _Nonnull op, ...)
 268     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 269     OBJC_ARM64_UNAVAILABLE;
 270
 271 OBJC_EXPORT void
 272 objc_msgSendSuper2_stret_debug(struct objc_super * _Nonnull super,
 273                                SEL _Nonnull op,...)
 274     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 275     OBJC_ARM64_UNAVAILABLE;
 276
 277 # if defined(__i386__)
 278 OBJC_EXPORT double
 279 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 280     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 281 # elif defined(__x86_64__)
 282 OBJC_EXPORT long double
 283 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 284     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 285 #  if __STDC_VERSION__ >= 199901L
 286 OBJC_EXPORT _Complex long double
 287 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 288     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 289 #  else
 290 OBJC_EXPORT void
 291 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 292     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 293 #  endif
 294 # endif
 295
 296 #endif
 297
 298 #if __OBJC2__
 299 // Lookup messengers.
 300 // These are not callable C functions. Do not call them directly.
 301 // The caller should set the method parameters, call objc_msgLookup(),
 302 // then immediately call the returned IMP.
 303 //
 304 // Generic ABI:
 305 // - Callee-saved registers are preserved.
 306 // - Receiver and selector registers may be modified. These values must
 307 //   be passed to the called IMP. Other parameter registers are preserved.
 308 // - Caller-saved non-parameter registers are not preserved. Some of
 309 //   these registers are used to pass data from objc_msgLookup() to
 310 //   the called IMP and must not be disturbed by the caller.
 311 // - Red zone is not preserved.
 312 // See each architecture's implementation for details.
 313
 314 OBJC_EXPORT void
 315 objc_msgLookup(void)
 316     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 317
 318 OBJC_EXPORT void
 319 objc_msgLookupSuper2(void)
 320     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 321
 322 OBJC_EXPORT void
 323 objc_msgLookup_stret(void)
 324     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 325     OBJC_ARM64_UNAVAILABLE;
 326
 327 OBJC_EXPORT void
 328 objc_msgLookupSuper2_stret(void)
 329     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 330     OBJC_ARM64_UNAVAILABLE;
 331
 332 # if defined(__i386__)
 333 OBJC_EXPORT void
 334 objc_msgLookup_fpret(void)
 335     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 336
 337 # elif defined(__x86_64__)
 338 OBJC_EXPORT void
 339 objc_msgLookup_fpret(void)
 340     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 341
 342 OBJC_EXPORT void
 343 objc_msgLookup_fp2ret(void)
 344     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 345 # endif
 346
 347 #endif
 348
 349 #if (TARGET_OS_OSX || TARGET_OS_SIMULATOR)  &&  defined(__x86_64__)
 350 // objc_msgSend_fixup() was used for vtable-dispatchable call sites.
 351 // The symbols remain exported on macOS for binary compatibility.
 352 // The symbols can probably be removed from iOS simulator but we haven't tried.
 353 OBJC_EXPORT void
 354 objc_msgSend_fixup(void)
 355     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 356
 357 OBJC_EXPORT void
 358 objc_msgSend_stret_fixup(void)
 359     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 360
 361 OBJC_EXPORT void
 362 objc_msgSendSuper2_fixup(void)
 363     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 364
 365 OBJC_EXPORT void
 366 objc_msgSendSuper2_stret_fixup(void)
 367     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 368
 369 OBJC_EXPORT void
 370 objc_msgSend_fpret_fixup(void)
 371     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 372
 373 OBJC_EXPORT void
 374 objc_msgSend_fp2ret_fixup(void)
 375     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 376 #endif
 377
 378 /* C++-compatible exception handling. */
 379 #if __OBJC2__
 380
 381 // Vtable for C++ exception typeinfo for Objective-C types.
 382 OBJC_EXPORT const void * _Nullable objc_ehtype_vtable[]
 383     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 384
 385 // C++ exception typeinfo for type `id`.
 386 OBJC_EXPORT struct objc_typeinfo OBJC_EHTYPE_id
 387     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 388
 389 // Exception personality function for Objective-C and Objective-C++ code.
 390 struct _Unwind_Exception;
 391 struct _Unwind_Context;
 392 OBJC_EXPORT int
 393 __objc_personality_v0(int version,
 394                       int actions,
 395                       uint64_t exceptionClass,
 396                       struct _Unwind_Exception * _Nonnull exceptionObject,
 397                       struct _Unwind_Context * _Nonnull context)
 398     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 399
 400 #endif
 401
 402 /* ARC */
 403
 404 OBJC_EXPORT id _Nullable
 405 objc_retainBlock(id _Nullable)
 406     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 407
 408
 409 /* Non-pointer isa */
 410
 411 #if __OBJC2__
 412
 413 // Extract class pointer from an isa field.
 414
 415 #if TARGET_OS_SIMULATOR && !TARGET_OS_IOSMAC
 416     // No simulators use nonpointer isa yet.
 417
 418 #elif __LP64__
 419 #   define OBJC_HAVE_NONPOINTER_ISA 1
 420 #   define OBJC_HAVE_PACKED_NONPOINTER_ISA 1
 421
 422 // Packed-isa version. This one is used directly by Swift code.
 423 // (Class)(isa & (uintptr_t)&objc_absolute_packed_isa_class_mask) == class ptr
 424 OBJC_EXPORT const struct { char c; } objc_absolute_packed_isa_class_mask
 425     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 426
 427 #elif (__ARM_ARCH_7K__ >= 2  ||  (__arm64__ && !__LP64__))
 428 #   define OBJC_HAVE_NONPOINTER_ISA 1
 429 #   define OBJC_HAVE_INDEXED_NONPOINTER_ISA 1
 430
 431 // Indexed-isa version.
 432 // if (isa & (uintptr_t)&objc_absolute_indexed_isa_magic_mask == (uintptr_t)&objc_absolute_indexed_isa_magic_value) {
 433 //     uintptr_t index = (isa & (uintptr_t)&objc_absolute_indexed_isa_index_mask) >> (uintptr_t)&objc_absolute_indexed_isa_index_shift;
 434 //     cls = objc_indexed_classes[index];
 435 // } else
 436 //     cls = (Class)isa;
 437 // }
 438 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_mask
 439     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 440 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_value
 441     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 442 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_mask
 443     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 444 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_shift
 445     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 446
 447 #endif
 448
 449 #endif
 450
 451
 452 /* Object class */
 453
 454 // This symbol might be required for binary compatibility, so we
 455 // declare it here where TAPI will see it.
 456 #if __OBJC__  &&  __OBJC2__
 457 #pragma clang diagnostic push
 458 #pragma clang diagnostic ignored "-Wobjc-interface-ivars"
 459 #if !defined(OBJC_DECLARE_SYMBOLS)
 460 __OSX_AVAILABLE(10.0)
 461 __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 462 __WATCHOS_UNAVAILABLE
 463 #   ifndef __APPLE_BLEACH_SDK__
 464 __BRIDGEOS_UNAVAILABLE
 465 #   endif
 466 #endif
 467 OBJC_ROOT_CLASS
 468 @interface Object {
 469     Class isa;
 470 }
 471 @end
 472 #pragma clang diagnostic pop
 473 #endif
 474
 475
 476 // _OBJC_ABI_H
 477 #endif