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 /* Runtime startup. */
  47
  48 // Old static initializer. Used by old crt1.o and old bug workarounds.
  49 OBJC_EXPORT void
  50 _objcInit(void)
  51     OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
  52
  53 /* Images */
  54
  55 // Description of an Objective-C image.
  56 // __DATA,__objc_imageinfo stores one of these.
  57 typedef struct objc_image_info {
  58     uint32_t version; // currently 0
  59     uint32_t flags;
  60
  61 #if __cplusplus >= 201103L
  62   private:
  63     enum : uint32_t {
  64         IsReplacement       = 1<<0,  // used for Fix&Continue, now ignored
  65         SupportsGC          = 1<<1,  // image supports GC
  66         RequiresGC          = 1<<2,  // image requires GC
  67         OptimizedByDyld     = 1<<3,  // image is from an optimized shared cache
  68         CorrectedSynthesize = 1<<4,  // used for an old workaround, now ignored
  69         IsSimulated         = 1<<5,  // image compiled for a simulator platform
  70         HasCategoryClassProperties  = 1<<6,  // class properties in category_t
  71
  72         SwiftVersionMaskShift = 8,
  73         SwiftVersionMask    = 0xff << SwiftVersionMaskShift  // Swift ABI version
  74
  75     };
  76    public:
  77     enum : uint32_t {
  78         SwiftVersion1   = 1,
  79         SwiftVersion1_2 = 2,
  80         SwiftVersion2   = 3,
  81         SwiftVersion3   = 4
  82     };
  83
  84   public:
  85     bool isReplacement()   const { return flags & IsReplacement; }
  86     bool supportsGC()      const { return flags & SupportsGC; }
  87     bool requiresGC()      const { return flags & RequiresGC; }
  88     bool optimizedByDyld() const { return flags & OptimizedByDyld; }
  89     bool hasCategoryClassProperties() const { return flags & HasCategoryClassProperties; }
  90     bool containsSwift()   const { return (flags & SwiftVersionMask) != 0; }
  91     uint32_t swiftVersion() const { return (flags & SwiftVersionMask) >> SwiftVersionMaskShift; }
  92 #endif
  93 } objc_image_info;
  94
  95 /*
  96 IsReplacement:
  97    Once used for Fix&Continue in old OS X object files (not final linked images)
  98    Not currently used.
  99
 100 SupportsGC:
 101    App: GC is required. Framework: GC is supported but not required.
 102
 103 RequiresGC:
 104    Framework: GC is required.
 105
 106 OptimizedByDyld:
 107    Assorted metadata precooked in the dyld shared cache.
 108    Never set for images outside the shared cache file itself.
 109
 110 CorrectedSynthesize:
 111    Once used on old iOS to mark images that did not have a particular
 112    miscompile. Not used by the runtime.
 113
 114 IsSimulated:
 115    Image was compiled for a simulator platform. Not used by the runtime.
 116
 117 HasClassProperties:
 118    New ABI: category_t.classProperties fields are present.
 119    Old ABI: Set by some compilers. Not used by the runtime.
 120 */
 121
 122
 123 /* Properties */
 124
 125 // Read or write an object property. Not all object properties use these.
 126 OBJC_EXPORT id _Nullable
 127 objc_getProperty(id _Nullable self, SEL _Nonnull _cmd,
 128                  ptrdiff_t offset, BOOL atomic)
 129     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 130
 131 OBJC_EXPORT void
 132 objc_setProperty(id _Nullable self, SEL _Nonnull _cmd, ptrdiff_t offset,
 133                  id _Nullable newValue, BOOL atomic, signed char shouldCopy)
 134     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 135
 136 OBJC_EXPORT void
 137 objc_setProperty_atomic(id _Nullable self, SEL _Nonnull _cmd,
 138                         id _Nullable newValue, ptrdiff_t offset)
 139     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 140
 141 OBJC_EXPORT void
 142 objc_setProperty_nonatomic(id _Nullable self, SEL _Nonnull _cmd,
 143                            id _Nullable newValue, ptrdiff_t offset)
 144     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 145
 146 OBJC_EXPORT void
 147 objc_setProperty_atomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 148                              id _Nullable newValue, ptrdiff_t offset)
 149     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 150
 151 OBJC_EXPORT void
 152 objc_setProperty_nonatomic_copy(id _Nullable self, SEL _Nonnull _cmd,
 153                                 id _Nullable newValue, ptrdiff_t offset)
 154     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 155
 156
 157 // Read or write a non-object property. Not all uses are C structs,
 158 // and not all C struct properties use this.
 159 OBJC_EXPORT void
 160 objc_copyStruct(void * _Nonnull dest, const void * _Nonnull src,
 161                 ptrdiff_t size, BOOL atomic, BOOL hasStrong)
 162     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 163
 164 // Perform a copy of a C++ object using striped locks. Used by non-POD C++ typed atomic properties.
 165 OBJC_EXPORT void
 166 objc_copyCppObjectAtomic(void * _Nonnull dest, const void * _Nonnull src,
 167                          void (* _Nonnull copyHelper)
 168                            (void * _Nonnull dest, const void * _Nonnull source))
 169     OBJC_AVAILABLE(10.8, 6.0, 9.0, 1.0, 2.0);
 170
 171 /* Classes. */
 172 #if __OBJC2__
 173 OBJC_EXPORT IMP _Nonnull _objc_empty_vtable
 174     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 175 #endif
 176 OBJC_EXPORT struct objc_cache _objc_empty_cache
 177     OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
 178
 179
 180 /* Messages */
 181
 182 #if __OBJC2__
 183 // objc_msgSendSuper2() takes the current search class, not its superclass.
 184 OBJC_EXPORT id _Nullable
 185 objc_msgSendSuper2(struct objc_super * _Nonnull super, SEL _Nonnull op, ...)
 186     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0);
 187
 188 OBJC_EXPORT void
 189 objc_msgSendSuper2_stret(struct objc_super * _Nonnull super,
 190                          SEL _Nonnull op,...)
 191     OBJC_AVAILABLE(10.6, 2.0, 9.0, 1.0, 2.0)
 192     OBJC_ARM64_UNAVAILABLE;
 193
 194 // objc_msgSend_noarg() may be faster for methods with no additional arguments.
 195 OBJC_EXPORT id _Nullable
 196 objc_msgSend_noarg(id _Nullable self, SEL _Nonnull _cmd)
 197     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 198 #endif
 199
 200 #if __OBJC2__
 201 // Debug messengers. Messengers used by the compiler have a debug flavor that
 202 // may perform extra sanity checking.
 203 // Old objc_msgSendSuper() does not have a debug version; this is OBJC2 only.
 204 // *_fixup() do not have debug versions; use non-fixup only for debug mode.
 205 OBJC_EXPORT id _Nullable
 206 objc_msgSend_debug(id _Nullable self, SEL _Nonnull op, ...)
 207     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 208
 209 OBJC_EXPORT id _Nullable
 210 objc_msgSendSuper2_debug(struct objc_super * _Nonnull super,
 211                          SEL _Nonnull op, ...)
 212     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 213
 214 OBJC_EXPORT void
 215 objc_msgSend_stret_debug(id _Nullable self, SEL _Nonnull op, ...)
 216     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 217     OBJC_ARM64_UNAVAILABLE;
 218
 219 OBJC_EXPORT void
 220 objc_msgSendSuper2_stret_debug(struct objc_super * _Nonnull super,
 221                                SEL _Nonnull op,...)
 222     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0)
 223     OBJC_ARM64_UNAVAILABLE;
 224
 225 # if defined(__i386__)
 226 OBJC_EXPORT double
 227 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 228     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 229 # elif defined(__x86_64__)
 230 OBJC_EXPORT long double
 231 objc_msgSend_fpret_debug(id _Nullable self, SEL _Nonnull op, ...)
 232     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 233 #  if __STDC_VERSION__ >= 199901L
 234 OBJC_EXPORT _Complex long double
 235 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 236     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 237 #  else
 238 OBJC_EXPORT void
 239 objc_msgSend_fp2ret_debug(id _Nullable self, SEL _Nonnull op, ...)
 240     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 241 #  endif
 242 # endif
 243
 244 #endif
 245
 246 #if __OBJC2__
 247 // Lookup messengers.
 248 // These are not callable C functions. Do not call them directly.
 249 // The caller should set the method parameters, call objc_msgLookup(),
 250 // then immediately call the returned IMP.
 251 //
 252 // Generic ABI:
 253 // - Callee-saved registers are preserved.
 254 // - Receiver and selector registers may be modified. These values must
 255 //   be passed to the called IMP. Other parameter registers are preserved.
 256 // - Caller-saved non-parameter registers are not preserved. Some of
 257 //   these registers are used to pass data from objc_msgLookup() to
 258 //   the called IMP and must not be disturbed by the caller.
 259 // - Red zone is not preserved.
 260 // See each architecture's implementation for details.
 261
 262 OBJC_EXPORT void
 263 objc_msgLookup(void)
 264     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 265
 266 OBJC_EXPORT void
 267 objc_msgLookupSuper2(void)
 268     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 269
 270 OBJC_EXPORT void
 271 objc_msgLookup_stret(void)
 272     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 273     OBJC_ARM64_UNAVAILABLE;
 274
 275 OBJC_EXPORT void
 276 objc_msgLookupSuper2_stret(void)
 277     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0)
 278     OBJC_ARM64_UNAVAILABLE;
 279
 280 # if defined(__i386__)
 281 OBJC_EXPORT void
 282 objc_msgLookup_fpret(void)
 283     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 284
 285 # elif defined(__x86_64__)
 286 OBJC_EXPORT void
 287 objc_msgLookup_fpret(void)
 288     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 289
 290 OBJC_EXPORT void
 291 objc_msgLookup_fp2ret(void)
 292     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 293 # endif
 294
 295 #endif
 296
 297 #if TARGET_OS_OSX  &&  defined(__x86_64__)
 298 // objc_msgSend_fixup() is used for vtable-dispatchable call sites.
 299 OBJC_EXPORT void
 300 objc_msgSend_fixup(void)
 301     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized")
 302     __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 303     __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE;
 304
 305 OBJC_EXPORT void
 306 objc_msgSend_stret_fixup(void)
 307     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized")
 308     __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 309     __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE;
 310
 311 OBJC_EXPORT void
 312 objc_msgSendSuper2_fixup(void)
 313     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized")
 314     __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 315     __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE;
 316
 317 OBJC_EXPORT void
 318 objc_msgSendSuper2_stret_fixup(void)
 319     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized")
 320     __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 321     __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE;
 322
 323 OBJC_EXPORT void
 324 objc_msgSend_fpret_fixup(void)
 325     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized")
 326     __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 327     __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE;
 328
 329 OBJC_EXPORT void
 330 objc_msgSend_fp2ret_fixup(void)
 331     __OSX_DEPRECATED(10.5, 10.8, "fixup dispatch is no longer optimized")
 332     __IOS_UNAVAILABLE __TVOS_UNAVAILABLE
 333     __WATCHOS_UNAVAILABLE __BRIDGEOS_UNAVAILABLE;
 334 #endif
 335
 336 /* C++-compatible exception handling. */
 337 #if __OBJC2__
 338
 339 // fixme these conflict with C++ compiler's internal definitions
 340 #if !defined(__cplusplus)
 341
 342 // Vtable for C++ exception typeinfo for Objective-C types.
 343 OBJC_EXPORT const void * _Nullableobjc_ehtype_vtable[]
 344     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 345
 346 // C++ exception typeinfo for type `id`.
 347 OBJC_EXPORT struct objc_typeinfo OBJC_EHTYPE_id
 348     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 349
 350 #endif
 351
 352 // Exception personality function for Objective-C and Objective-C++ code.
 353 struct _Unwind_Exception;
 354 struct _Unwind_Context;
 355 OBJC_EXPORT int
 356 __objc_personality_v0(int version,
 357                       int actions,
 358                       uint64_t exceptionClass,
 359                       struct _Unwind_Exception * _Nonnull exceptionObject,
 360                       struct _Unwind_Context * _Nonnull context)
 361     OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
 362
 363 #endif
 364
 365 /* ARC */
 366
 367 OBJC_EXPORT id _Nullable
 368 objc_retainBlock(id _Nullable)
 369     OBJC_AVAILABLE(10.7, 5.0, 9.0, 1.0, 2.0);
 370
 371
 372 /* Non-pointer isa */
 373
 374 #if __OBJC2__
 375
 376 // Extract class pointer from an isa field.
 377
 378 #if  TARGET_OS_SIMULATOR
 379     // No simulators use nonpointer isa yet.
 380
 381 #elif __LP64__
 382 #   define OBJC_HAVE_NONPOINTER_ISA 1
 383 #   define OBJC_HAVE_PACKED_NONPOINTER_ISA 1
 384
 385 // Packed-isa version. This one is used directly by Swift code.
 386 // (Class)(isa & (uintptr_t)&objc_absolute_packed_isa_class_mask) == class ptr
 387 OBJC_EXPORT const struct { char c; } objc_absolute_packed_isa_class_mask
 388     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 389
 390 #elif __ARM_ARCH_7K__ >= 2
 391 #   define OBJC_HAVE_NONPOINTER_ISA 1
 392 #   define OBJC_HAVE_INDEXED_NONPOINTER_ISA 1
 393
 394 // Indexed-isa version.
 395 // if (isa & (uintptr_t)&objc_absolute_indexed_isa_magic_mask == (uintptr_t)&objc_absolute_indexed_isa_magic_value) {
 396 //     uintptr_t index = (isa & (uintptr_t)&objc_absolute_indexed_isa_index_mask) >> (uintptr_t)&objc_absolute_indexed_isa_index_shift;
 397 //     cls = objc_indexed_classes[index];
 398 // } else
 399 //     cls = (Class)isa;
 400 // }
 401 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_mask
 402     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 403 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_magic_value
 404     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 405 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_mask
 406     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 407 OBJC_EXPORT const struct { char c; } objc_absolute_indexed_isa_index_shift
 408     OBJC_AVAILABLE(10.12, 10.0, 10.0, 3.0, 2.0);
 409
 410 #endif
 411
 412 // OBJC2
 413 #endif
 414
 415 // _OBJC_ABI_H
 416 #endif