libobjc/objc-private/module-abi-8.h

   1 /* Definitions of Module Structures used by ABI version 8
   2    Copyright (C) 1993, 1995, 1996, 1997, 2001, 2002, 2003, 2004, 2005,
   3    2007, 2009, 2010 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under the
   8 terms of the GNU General Public License as published by the Free Software
   9 Foundation; either version 3, or (at your option) any later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13 FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  14 details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #ifndef __objc_private_module_abi_8_INCLUDE_GNU
  26 #define __objc_private_module_abi_8_INCLUDE_GNU
  27
  28 /* For every class which happens to have statically allocated instances in
  29    this module, one OBJC_STATIC_INSTANCES is allocated by the compiler.
  30    INSTANCES is NULL terminated and points to all statically allocated
  31    instances of this class.  */
  32 struct objc_static_instances
  33 {
  34   char *class_name;
  35 #ifdef __cplusplus
  36   id instances[1];
  37 #else
  38   id instances[0];
  39 #endif
  40 };
  41
  42 /* Whereas a Module (defined further down) is the root (typically) of a file,
  43    a Symtab is the root of the class and category definitions within the
  44    module.
  45
  46    A Symtab contains a variable length array of pointers to classes and
  47    categories  defined in the module.   */
  48 struct objc_symtab
  49 {
  50   unsigned long sel_ref_cnt;  /* Unused (always set to 0). */
  51   struct objc_selector *refs; /* The table of selectors referenced in
  52                                  this module.  This is terminated by a
  53                                  selector with NULL sel_id and NULL
  54                                  sel_types.  Note that we use the type
  55                                  'struct objc_selector *' and not
  56                                  'SEL' (which is 'const struct
  57                                  objc_selector *') because the sel_id
  58                                  of these selectors is patched up by
  59                                  the runtime when the module is
  60                                  loaded.  */
  61   unsigned short cls_def_cnt; /* Number of classes compiled (defined)
  62                                  in the module. */
  63   unsigned short cat_def_cnt; /* Number of categories compiled
  64                                  (defined) in the module. */
  65   void      *defs[1];         /* Variable array of pointers.
  66                                  cls_def_cnt of type Class followed by
  67                                  cat_def_cnt of type Category_t,
  68                                  followed by a NULL terminated array
  69                                  of objc_static_instances. */
  70 };
  71
  72 /* The compiler generates one of these structures for each module that
  73    composes the executable (eg main.m).
  74
  75    This data structure is the root of the definition tree for the
  76    module.
  77
  78    A collect program runs between ld stages and creates a ObjC ctor
  79    array.  That array holds a pointer to each module structure of the
  80    executable.  */
  81 struct objc_module
  82 {
  83   unsigned long version;      /* Version of the Module data
  84                                  structure.  */
  85   unsigned long size;         /* sizeof(Module) according to the
  86                                  compiler - only used to sanity check
  87                                  that it matches sizeof(Module)
  88                                  according to the runtime.  */
  89   const char* name;           /* Name of the file used to compile the
  90                                  module - not set by modern compilers
  91                                  for security reasons.  */
  92   struct objc_symtab *symtab; /* Pointer to the Symtab of the module.
  93                                  The Symtab holds an array of pointers
  94                                  to the classes and categories defined
  95                                  in the module. */
  96 };
  97
  98 /* The compiler generates one of these structures for a class that has
  99    instance variables defined in its specification.  */
 100 struct objc_ivar
 101 {
 102   const char* ivar_name;  /* Name of the instance variable as entered
 103                              in the class definition. */
 104   const char* ivar_type;  /* Description of the Ivar's type.  Useful
 105                              for debuggers. */
 106   int        ivar_offset; /* Byte offset from the base address of the
 107                              instance structure to the variable. */
 108 };
 109
 110 struct objc_ivar_list
 111 {
 112   int   ivar_count;              /* Number of structures (Ivar)
 113                                     contained in the list.  One
 114                                     structure per instance variable
 115                                     defined in the class. */
 116   struct objc_ivar ivar_list[1]; /* Variable length structure. */
 117 };
 118
 119 /* The compiler generates one (or more) of these structures for a
 120    class that has methods defined in its specification.
 121
 122    The implementation of a class can be broken into separate pieces in
 123    a file and categories can break them across modules. To handle this
 124    problem is a singly linked list of methods.  */
 125 struct objc_method
 126 {
 127   SEL         method_name;  /* This variable is the method's name.
 128                                The compiler puts a char* here, and
 129                                it's replaced by a real SEL at runtime
 130                                when the method is registered.  */
 131   const char* method_types; /* Description of the method's parameter
 132                                list.  Used when registering the
 133                                selector with the runtime.  When that
 134                                happens, method_name will contain the
 135                                method's parameter list.  */
 136   IMP         method_imp;   /* Address of the method in the
 137                                executable. */
 138 };
 139
 140 struct objc_method_list
 141 {
 142   struct objc_method_list*  method_next; /* This variable is used to
 143                                             link a method list to
 144                                             another.  It is a singly
 145                                             linked list. */
 146   int            method_count;            /* Number of methods defined
 147                                              in this structure. */
 148   struct objc_method method_list[1];      /* Variable length
 149                                              structure. */
 150 };
 151
 152 /* Note that a 'struct objc_method_description' as embedded inside a
 153    Protocol uses the same trick as a 'struct objc_method': the
 154    method_name is a 'char *' according to the compiler, who puts the
 155    method name as a string in there.  At runtime, the selectors need
 156    to be registered, and the method_name then becomes a SEL.  */
 157 struct objc_method_description_list
 158 {
 159   int count;
 160   struct objc_method_description list[1];
 161 };
 162
 163 struct objc_protocol {
 164   struct objc_class* class_pointer;
 165   char *protocol_name;
 166   struct objc_protocol_list *protocol_list;
 167   struct objc_method_description_list *instance_methods, *class_methods;
 168 };
 169
 170
 171 struct objc_protocol_list
 172 {
 173   struct objc_protocol_list *next;
 174   size_t count;
 175   struct objc_protocol *list[1];
 176 };
 177
 178 /*
 179   The compiler generates one of these structures for each class.
 180
 181   This structure is the definition for classes.
 182
 183   This structure is generated by the compiler in the executable and
 184   used by the run-time during normal messaging operations.  Therefore
 185   some members change type. The compiler generates "char* const" and
 186   places a string in the following member variables: super_class.
 187 */
 188 struct objc_class {
 189   struct objc_class*  class_pointer;    /* Pointer to the class's meta
 190                                            class. */
 191   struct objc_class*  super_class;      /* Pointer to the super
 192                                            class. NULL for class
 193                                            Object. */
 194   const char*         name;             /* Name of the class. */
 195   long                version;          /* Unknown. */
 196   unsigned long       info;             /* Bit mask.  See class masks
 197                                            defined below. */
 198   long                instance_size;    /* Size in bytes of the class.
 199                                            The sum of the class
 200                                            definition and all super
 201                                            class definitions. */
 202 #ifdef _WIN64
 203   /* We pad the structure manually to prevent warning when -Wpadded is
 204      used.  The compiler automatically pads the structures that it
 205      generates, so this manually padded structure still matches the
 206      one generated by the compiler, but if we don't pad manually,
 207      -Wpadded detects that padding is being added and generates
 208      annoying warnings.  This hack is necessary as on LLP64 targets
 209      sizeof (long) isn't equal to sizeof (void *).  */
 210   long pad;
 211 #endif
 212   struct objc_ivar_list* ivars;         /* Pointer to a structure that
 213                                            describes the instance
 214                                            variables in the class
 215                                            definition.  NULL indicates
 216                                            no instance variables.
 217                                            Does not include super
 218                                            class variables. */
 219   struct objc_method_list*  methods;    /* Linked list of instance
 220                                            methods defined for the
 221                                            class. */
 222   struct sarray *    dtable;            /* Pointer to instance method
 223                                            dispatch table. */
 224   struct objc_class* subclass_list;     /* Subclasses */
 225   struct objc_class* sibling_class;
 226
 227   struct objc_protocol_list *protocols; /* Protocols conformed to */
 228   void* gc_object_type;
 229 };
 230
 231 /* This is used to assure consistent access to the info field of
 232    classes.  */
 233 #ifndef HOST_BITS_PER_LONG
 234 # define HOST_BITS_PER_LONG  (sizeof(long)*8)
 235 #endif
 236
 237 #define __CLS_INFO(cls) ((cls)->info)
 238 #define __CLS_ISINFO(cls, mask) ((__CLS_INFO(cls)&mask)==mask)
 239 #define __CLS_SETINFO(cls, mask) (__CLS_INFO(cls) |= mask)
 240 #define __CLS_SETNOTINFO(cls, mask) (__CLS_INFO(cls) &= ~mask)
 241
 242 /* The structure is of type MetaClass */
 243 #define _CLS_META 0x2L
 244 #define CLS_ISMETA(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_META))
 245
 246 /* The structure is of type Class */
 247 #define _CLS_CLASS 0x1L
 248 #define CLS_ISCLASS(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_CLASS))
 249
 250 /* The class is initialized within the runtime.  This means that it
 251    has had correct super and sublinks assigned.  */
 252 #define _CLS_RESOLV 0x8L
 253 #define CLS_ISRESOLV(cls) __CLS_ISINFO(cls, _CLS_RESOLV)
 254 #define CLS_SETRESOLV(cls) __CLS_SETINFO(cls, _CLS_RESOLV)
 255
 256 /* The class has been send a +initialize message or a such is not
 257    defined for this class.  */
 258 #define _CLS_INITIALIZED 0x04L
 259 #define CLS_ISINITIALIZED(cls) __CLS_ISINFO(cls, _CLS_INITIALIZED)
 260 #define CLS_SETINITIALIZED(cls) __CLS_SETINFO(cls, _CLS_INITIALIZED)
 261
 262 /* The class is being constructed; it has been allocated using
 263    objc_allocateClassPair(), but has not been registered yet by using
 264    objc_registerClassPair().  This means it is possible to freely add
 265    instance variables to the class, but it can't be used for anything
 266    yet.  */
 267 #define _CLS_IN_CONSTRUCTION 0x10L
 268 #define CLS_IS_IN_CONSTRUCTION(cls) __CLS_ISINFO(cls, _CLS_IN_CONSTRUCTION)
 269 #define CLS_SET_IN_CONSTRUCTION(cls) __CLS_SETINFO(cls, _CLS_IN_CONSTRUCTION)
 270 #define CLS_SET_NOT_IN_CONSTRUCTION(cls) __CLS_SETNOTINFO(cls, _CLS_IN_CONSTRUCTION)
 271
 272 /* The class number of this class.  This must be the same for both the
 273    class and its meta class object.  */
 274 #define CLS_GETNUMBER(cls) (__CLS_INFO(cls) >> (HOST_BITS_PER_LONG/2))
 275 #define CLS_SETNUMBER(cls, num) \
 276   ({ (cls)->info <<= (HOST_BITS_PER_LONG/2); \
 277      (cls)->info >>= (HOST_BITS_PER_LONG/2); \
 278      __CLS_SETINFO(cls, (((unsigned long)num) << (HOST_BITS_PER_LONG/2))); })
 279
 280 /* The compiler generates one of these structures for each category.
 281    A class may have many categories and contain both instance and
 282    factory methods.  */
 283 struct objc_category
 284 {
 285   const char*   category_name;                /* Name of the category.
 286                                                  Name contained in the
 287                                                  () of the category
 288                                                  definition.  */
 289   const char*   class_name;                   /* Name of the class to
 290                                                  which the category
 291                                                  belongs.  */
 292   struct objc_method_list  *instance_methods; /* Linked list of
 293                                                  instance methods
 294                                                  defined in the
 295                                                  category. NULL
 296                                                  indicates no instance
 297                                                  methods defined.  */
 298   struct objc_method_list *class_methods;     /* Linked list of
 299                                                  factory methods
 300                                                  defined in the
 301                                                  category.  NULL
 302                                                  indicates no class
 303                                                  methods defined.  */
 304   struct objc_protocol_list *protocols;       /* List of Protocols
 305                                                  conformed to.  */
 306 };
 307
 308 #endif /* __objc_private_module_abi_8_INCLUDE_GNU */