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         IsReplacement       = 1<<0,  // used for Fix&Continue, now ignored
 104         SupportsGC          = 1<<1,  // image supports GC
 105         RequiresGC          = 1<<2,  // image requires GC
 106         OptimizedByDyld     = 1<<3,  // image is from an optimized shared cache
 107         CorrectedSynthesize = 1<<4,  // used for an old workaround, now ignored
 108         IsSimulated         = 1<<5,  // image compiled for a simulator platform
 109         HasCategoryClassProperties  = 1<<6,  // class properties in category_t
 110
 111         SwiftVersionMaskShift = 8,
 112         SwiftVersionMask    = 0xff << SwiftVersionMaskShift  // Swift ABI version
 113
 114     };
 115    public:
 116     enum : uint32_t {
 117         SwiftVersion1   = 1,
 118         SwiftVersion1_2 = 2,
 119         SwiftVersion2   = 3,
 120         SwiftVersion3   = 4
 121     };
 122
 123   public:
 124     bool isReplacement()   const { return flags & IsReplacement; }
 125     bool supportsGC()      const { return flags & SupportsGC; }
 126     bool requiresGC()      const { return flags & RequiresGC; }
 127     bool optimizedByDyld() const { return flags & OptimizedByDyld; }
 128     bool hasCategoryClassProperties() const { return flags & HasCategoryClassProperties; }
 129     bool containsSwift()   const { return (flags & SwiftVersionMask) != 0; }
 130     uint32_t swiftVersion() const { return (flags & SwiftVersionMask) >> SwiftVersionMaskShift; }
 131 #endif
 132 } objc_image_info;
 133
 134 /*
 135 IsReplacement:
 136    Once used for Fix&Continue in old OS X object files (not final linked images)
 137    Not currently used.
 138
 139 SupportsGC:
 140    App: GC is required. Framework: GC is supported but not required.
 141
 142 RequiresGC:
 143    Framework: GC is required.
 144
 145 OptimizedByDyld:
 146    Assorted metadata precooked in the dyld shared cache.
 147    Never set for images outside the shared cache file itself.
 148
 149 CorrectedSynthesize:
 150    Once used on old iOS to mark images that did not have a particular
 151    miscompile. Not used by the runtime.
 152
 153 IsSimulated:
 154    Image was compiled for a simulator platform. Not used by the runtime.
 155
 156 HasClassProperties:
 157    New ABI: category_t.classProperties fields are present.
 158    Old ABI: Set by some compilers. Not used by the runtime.
 159 */
 160
 161
 162 /* Properties */
 163
 164 // Read or write an object property. Not all object properties use these.
 165 OBJC_EXPORT id _Nullable
 166 objc_getProperty(id _Nullable self, SEL _Nonnull _cmd,
 167                  ptrdiff_t offset, BOOL atomic)
 168     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 169
 170 OBJC_EXPORT void
 171 objc_setProperty(id _Nullable self, SEL _Nonnull _cmd, ptrdiff_t offset,
 172                  id _Nullable newValue, BOOL atomic, signed char shouldCopy)
 173     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 174
 175 OBJC_EXPORT void
 176 objc_setProperty_atomic(id _Nullable self, SEL _Nonnull _cmd,
 177                         id _Nullable newValue, ptrdiff_t offset)
 178     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 179
 180 OBJC_EXPORT void
 181 objc_setProperty_nonatomic(id _Nullable self, SEL _Nonnull _cmd,
 182                            id _Nullable newValue, ptrdiff_t offset)
 183     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 184
 185 OBJC_EXPORT void
 186 objc_setProperty_atomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 187                              id _Nullable newValue, ptrdiff_t offset)
 188     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 189
 190 OBJC_EXPORT void
 191 objc_setProperty_nonatomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 192                                 id _Nullable newValue, ptrdiff_t offset)
 193     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 194
 195
 196 // Read or write a non-object property. Not all uses are C structs,
 197 // and not all C struct properties use this.
 198 OBJC_EXPORT void
 199 objc_copyStruct(void * _Nonnull dest, const void * _Nonnull src,
 200                 ptrdiff_t size, BOOL atomic, BOOL hasStrong)
 201     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 202
 203 // Perform a copy of a C++ object using striped locks. Used by non-POD C++ typed atomic properties.
 204 OBJC_EXPORT void
 205 objc_copyCppObjectAtomic(void * _Nonnull dest, const void * _Nonnull src,
 206                          void (* _Nonnull copyHelper)
 207                            (void * _Nonnull dest, const void * _Nonnull source))
 208     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 209
 210 /* Classes. */
 211 #if __OBJC2__
 212 OBJC_EXPORT IMP _Nonnull _objc_empty_vtable
 213     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 214 #endif
 215 OBJC_EXPORT struct objc_cache _objc_empty_cache
 216     OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
 217
 218
 219 /* Messages */
 220
 221 #if __OBJC2__
 222 // objc_msgSendSuper2() takes the current search class, not its superclass.
 223 OBJC_EXPORT id _Nullable
 224 objc_msgSendSuper2(struct objc_super * _Nonnull super, SEL _Nonnull op, ...)
 225     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0);
 226
 227 OBJC_EXPORT void
 228 objc_msgSendSuper2_stret(struct objc_super * _Nonnull super,
 229                          SEL _Nonnull op,...)
 230     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0)
 231     OBJC_ARM64_UNAVAILABLE;
 232
 233 // objc_msgSend_noarg() may be faster for methods with no additional arguments.
 234 OBJC_EXPORT id _Nullable
 235 objc_msgSend_noarg(id _Nullable self, SEL _Nonnull _cmd)
 236     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 237 #endif
 238
 239 #if __OBJC2__
 240 // Debug messengers. Messengers used by the compiler have a debug flavor that
 241 // may perform extra sanity checking.
 242 // Old objc_msgSendSuper() does not have a debug version; this is OBJC2 only.
 243 // *_fixup() do not have debug versions; use non-fixup only for debug mode.
 244 OBJC_EXPORT id _Nullable
 245 objc_msgSend_debug(id _Nullable self, SEL _Nonnull op, ...)
 246     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 247
 248 OBJC_EXPORT id _Nullable
 249 objc_msgSendSuper2_debug(struct objc_super * _Nonnull super,
 250                          SEL _Nonnull op, ...)
 251     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 252
 253 OBJC_EXPORT void
 254 objc_msgSend_stret_debug(id _Nullable self, SEL _Nonnull op, ...)
 255     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 256     OBJC_ARM64_UNAVAILABLE;
 257
 258 OBJC_EXPORT void
 259 objc_msgSendSuper2_stret_debug(struct objc_super * _Nonnull super,
 260                                SEL _Nonnull op,...)
 261     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 262     OBJC_ARM64_UNAVAILABLE;
 263
 264 # if defined(__i386__)
 265 OBJC_EXPORT double
 266 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 267     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 268 # elif defined(__x86_64__)
 269 OBJC_EXPORT long double
 270 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 271     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 272 #  if __STDC_VERSION__ >= 199901L
 273 OBJC_EXPORT _Complex long double
 274 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 275     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 276 #  else
 277 OBJC_EXPORT void
 278 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 279     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 280 #  endif
 281 # endif
 282
 283 #endif
 284
 285 #if __OBJC2__
 286 // Lookup messengers.
 287 // These are not callable C functions. Do not call them directly.
 288 // The caller should set the method parameters, call objc_msgLookup(),
 289 // then immediately call the returned IMP.
 290 //
 291 // Generic ABI:
 292 // - Callee-saved registers are preserved.
 293 // - Receiver and selector registers may be modified. These values must
 294 //   be passed to the called IMP. Other parameter registers are preserved.
 295 // - Caller-saved non-parameter registers are not preserved. Some of
 296 //   these registers are used to pass data from objc_msgLookup() to
 297 //   the called IMP and must not be disturbed by the caller.
 298 // - Red zone is not preserved.
 299 // See each architecture's implementation for details.
 300
 301 OBJC_EXPORT void
 302 objc_msgLookup(void)
 303     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 304
 305 OBJC_EXPORT void
 306 objc_msgLookupSuper2(void)
 307     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 308
 309 OBJC_EXPORT void
 310 objc_msgLookup_stret(void)
 311     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 312     OBJC_ARM64_UNAVAILABLE;
 313
 314 OBJC_EXPORT void
 315 objc_msgLookupSuper2_stret(void)
 316     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 317     OBJC_ARM64_UNAVAILABLE;
 318
 319 # if defined(__i386__)
 320 OBJC_EXPORT void
 321 objc_msgLookup_fpret(void)
 322     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 323
 324 # elif defined(__x86_64__)
 325 OBJC_EXPORT void
 326 objc_msgLookup_fpret(void)
 327     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 328
 329 OBJC_EXPORT void
 330 objc_msgLookup_fp2ret(void)
 331     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 332 # endif
 333
 334 #endif
 335
 336 #if (TARGET_OS_OSX || TARGET_OS_SIMULATOR)  &&  defined(__x86_64__)
 337 // objc_msgSend_fixup() was used for vtable-dispatchable call sites.
 338 // The symbols remain exported on macOS for binary compatibility.
 339 // The symbols can probably be removed from iOS simulator but we haven't tried.
 340 OBJC_EXPORT void
 341 objc_msgSend_fixup(void)
 342     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 343
 344 OBJC_EXPORT void
 345 objc_msgSend_stret_fixup(void)
 346     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 347
 348 OBJC_EXPORT void
 349 objc_msgSendSuper2_fixup(void)
 350     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 351
 352 OBJC_EXPORT void
 353 objc_msgSendSuper2_stret_fixup(void)
 354     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 355
 356 OBJC_EXPORT void
 357 objc_msgSend_fpret_fixup(void)
 358     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 359
 360 OBJC_EXPORT void
 361 objc_msgSend_fp2ret_fixup(void)
 362     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized");
 363 #endif
 364
 365 /* C++-compatible exception handling. */
 366 #if __OBJC2__
 367
 368 // Vtable for C++ exception typeinfo for Objective-C types.
 369 OBJC_EXPORT const void * _Nullable objc_ehtype_vtable[]
 370     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 371
 372 // C++ exception typeinfo for type `id`.
 373 OBJC_EXPORT struct objc_typeinfo OBJC_EHTYPE_id
 374     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 375
 376 // Exception personality function for Objective-C and Objective-C++ code.
 377 struct _Unwind_Exception;
 378 struct _Unwind_Context;
 379 OBJC_EXPORT int
 380 __objc_personality_v0(int version,
 381                       int actions,
 382                       uint64_t exceptionClass,
 383                       struct _Unwind_Exception * _Nonnull exceptionObject,
 384                       struct _Unwind_Context * _Nonnull context)
 385     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 386
 387 #endif
 388
 389 /* ARC */
 390
 391 OBJC_EXPORT id _Nullable
 392 objc_retainBlock(id _Nullable)
 393     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 394
 395
 396 /* Non-pointer isa */
 397
 398 #if __OBJC2__
 399
 400 // Extract class pointer from an isa field.
 401
 402 #if TARGET_OS_SIMULATOR && !TARGET_OS_IOSMAC
 403     // No simulators use nonpointer isa yet.
 404
 405 #elif __LP64__
 406 #   define OBJC_HAVE_NONPOINTER_ISA 1
 407 #   define OBJC_HAVE_PACKED_NONPOINTER_ISA 1
 408
 409 // Packed-isa version. This one is used directly by Swift code.
 410 // (Class)(isa & (uintptr_t)&objc_absolute_packed_isa_class_mask) == class ptr
 411 OBJC_EXPORT const struct { char c; } objc_absolute_packed_isa_class_mask
 412     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 413
 414 #elif (__ARM_ARCH_7K__ >= 2  ||  (__arm64__ && !__LP64__))
 415 #   define OBJC_HAVE_NONPOINTER_ISA 1
 416 #   define OBJC_HAVE_INDEXED_NONPOINTER_ISA 1
 417
 418 // Indexed-isa version.
 419 // if (isa & (uintptr_t)&objc_absolute_indexed_isa_magic_mask == (uintptr_t)&objc_absolute_indexed_isa_magic_value) {
 420 //     uintptr_t index = (isa & (uintptr_t)&objc_absolute_indexed_isa_index_mask) >> (uintptr_t)&objc_absolute_indexed_isa_index_shift;
 421 //     cls = objc_indexed_classes[index];
 422 // } else
 423 //     cls = (Class)isa;
 424 // }
 425 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_mask
 426     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 427 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_value
 428     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 429 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_mask
 430     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 431 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_shift
 432     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 433
 434 #endif
 435
 436 #endif
 437
 438
 439 /* Object class */
 440
 441 // This symbol might be required for binary compatibility, so we
 442 // declare it here where TAPI will see it.
 443 #if __OBJC__  &&  __OBJC2__
 444 #pragma clang diagnostic push
 445 #pragma clang diagnostic ignored "-Wobjc-interface-ivars"
 446 #if !defined(OBJC_DECLARE_SYMBOLS)
 447 __OSX_AVAILABLE(10.0)
 448 __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 449 __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE
 450 #endif
 451 OBJC_ROOT_CLASS
 452 @interface Object {
 453     Class isa;
 454 }
 455 @end
 456 #pragma clang diagnostic pop
 457 #endif
 458
 459
 460 // _OBJC_ABI_H
 461 #endif