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;  /* Unknown. */
  51   SEL        refs;            /* Unknown. */
  52   unsigned short cls_def_cnt; /* Number of classes compiled (defined)
  53                                  in the module. */
  54   unsigned short cat_def_cnt; /* Number of categories compiled
  55                                  (defined) in the module. */
  56   void      *defs[1];         /* Variable array of pointers.
  57                                  cls_def_cnt of type Class followed by
  58                                  cat_def_cnt of type Category_t,
  59                                  followed by a NULL terminated array
  60                                  of objc_static_instances. */
  61 };
  62
  63 /* The compiler generates one of these structures for each module that
  64    composes the executable (eg main.m).
  65
  66    This data structure is the root of the definition tree for the
  67    module.
  68
  69    A collect program runs between ld stages and creates a ObjC ctor
  70    array.  That array holds a pointer to each module structure of the
  71    executable.  */
  72 struct objc_module
  73 {
  74   unsigned long version;      /* Version of the Module data
  75                                  structure.  */
  76   unsigned long size;         /* sizeof(Module) according to the
  77                                  compiler - only used to sanity check
  78                                  that it matches sizeof(Module)
  79                                  according to the runtime.  */
  80   const char* name;           /* Name of the file used to compile the
  81                                  module - not set by modern compilers
  82                                  for security reasons.  */
  83   struct objc_symtab *symtab; /* Pointer to the Symtab of the module.
  84                                  The Symtab holds an array of pointers
  85                                  to the classes and categories defined
  86                                  in the module. */
  87 };
  88
  89 /* The compiler generates one of these structures for a class that has
  90    instance variables defined in its specification.  */
  91 struct objc_ivar
  92 {
  93   const char* ivar_name;  /* Name of the instance variable as entered
  94                              in the class definition. */
  95   const char* ivar_type;  /* Description of the Ivar's type.  Useful
  96                              for debuggers. */
  97   int        ivar_offset; /* Byte offset from the base address of the
  98                              instance structure to the variable. */
  99 };
 100
 101 struct objc_ivar_list
 102 {
 103   int   ivar_count;              /* Number of structures (Ivar)
 104                                     contained in the list.  One
 105                                     structure per instance variable
 106                                     defined in the class. */
 107   struct objc_ivar ivar_list[1]; /* Variable length structure. */
 108 };
 109
 110 /* The compiler generates one (or more) of these structures for a
 111    class that has methods defined in its specification.
 112
 113    The implementation of a class can be broken into separate pieces in
 114    a file and categories can break them across modules. To handle this
 115    problem is a singly linked list of methods.  */
 116 struct objc_method
 117 {
 118   SEL         method_name;  /* This variable is the method's name.
 119                                The compiler puts a char* here, and
 120                                it's replaced by a real SEL at runtime
 121                                when the method is registered.  */
 122   const char* method_types; /* Description of the method's parameter
 123                                list.  Used when registering the
 124                                selector with the runtime.  When that
 125                                happens, method_name will contain the
 126                                method's parameter list.  */
 127   IMP         method_imp;   /* Address of the method in the
 128                                executable. */
 129 };
 130
 131 struct objc_method_list
 132 {
 133   struct objc_method_list*  method_next; /* This variable is used to
 134                                             link a method list to
 135                                             another.  It is a singly
 136                                             linked list. */
 137   int            method_count;            /* Number of methods defined
 138                                              in this structure. */
 139   struct objc_method method_list[1];      /* Variable length
 140                                              structure. */
 141 };
 142
 143 /* Currently defined in Protocol.m (that definition should go away
 144    once we include this file).  Note that a 'struct
 145    objc_method_description' as embedded inside a Protocol uses the
 146    same trick as a 'struct objc_method': the method_name is a 'char *'
 147    according to the compiler, who puts the method name as a string in
 148    there.  At runtime, the selectors need to be registered, and the
 149    method_name then becomes a SEL.  */
 150 struct objc_method_description_list
 151 {
 152   int count;
 153   struct objc_method_description list[1];
 154 };
 155
 156 /* Currently defined by objc/objc.h.  */
 157 /*
 158 struct objc_protocol {
 159   struct objc_class* class_pointer;
 160   char *protocol_name;
 161   struct objc_protocol_list *protocol_list;
 162   struct objc_method_description_list *instance_methods, *class_methods;
 163 };
 164 */
 165
 166 struct objc_protocol_list
 167 {
 168   struct objc_protocol_list *next;
 169   size_t count;
 170   Protocol *list[1];
 171 };
 172
 173 /*
 174   The compiler generates one of these structures for each class.
 175
 176   This structure is the definition for classes.
 177
 178   This structure is generated by the compiler in the executable and
 179   used by the run-time during normal messaging operations.  Therefore
 180   some members change type. The compiler generates "char* const" and
 181   places a string in the following member variables: super_class.
 182 */
 183 #ifndef __objc_STRUCT_OBJC_CLASS_defined
 184 struct objc_class {
 185   struct objc_class*  class_pointer;    /* Pointer to the class's meta
 186                                            class. */
 187   struct objc_class*  super_class;      /* Pointer to the super
 188                                            class. NULL for class
 189                                            Object. */
 190   const char*         name;             /* Name of the class. */
 191   long                version;          /* Unknown. */
 192   unsigned long       info;             /* Bit mask.  See class masks
 193                                            defined below. */
 194   long                instance_size;    /* Size in bytes of the class.
 195                                            The sum of the class
 196                                            definition and all super
 197                                            class definitions. */
 198 #ifdef _WIN64
 199   /* We pad the structure manually to prevent warning when -Wpadded is
 200      used.  The compiler automatically pads the structures that it
 201      generates, so this manually padded structure still matches the
 202      one generated by the compiler, but if we don't pad manually,
 203      -Wpadded detects that padding is being added and generates
 204      annoying warnings.  This hack is necessary as on LLP64 targets
 205      sizeof (long) isn't equal to sizeof (void *).  */
 206   long pad;
 207 #endif
 208   struct objc_ivar_list* ivars;         /* Pointer to a structure that
 209                                            describes the instance
 210                                            variables in the class
 211                                            definition.  NULL indicates
 212                                            no instance variables.
 213                                            Does not include super
 214                                            class variables. */
 215   struct objc_method_list*  methods;    /* Linked list of instance
 216                                            methods defined for the
 217                                            class. */
 218   struct sarray *    dtable;            /* Pointer to instance method
 219                                            dispatch table. */
 220   struct objc_class* subclass_list;     /* Subclasses */
 221   struct objc_class* sibling_class;
 222
 223   struct objc_protocol_list *protocols; /* Protocols conformed to */
 224   void* gc_object_type;
 225 };
 226 #endif /* __objc_STRUCT_OBJC_CLASS_defined */
 227
 228 /* This is used to assure consistent access to the info field of
 229    classes.  */
 230 #ifndef HOST_BITS_PER_LONG
 231 # define HOST_BITS_PER_LONG  (sizeof(long)*8)
 232 #endif
 233
 234 #define __CLS_INFO(cls) ((cls)->info)
 235 #define __CLS_ISINFO(cls, mask) ((__CLS_INFO(cls)&mask)==mask)
 236 #define __CLS_SETINFO(cls, mask) (__CLS_INFO(cls) |= mask)
 237 #define __CLS_SETNOTINFO(cls, mask) (__CLS_INFO(cls) &= ~mask)
 238
 239 /* The structure is of type MetaClass */
 240 #define _CLS_META 0x2L
 241 #define CLS_ISMETA(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_META))
 242
 243 /* The structure is of type Class */
 244 #define _CLS_CLASS 0x1L
 245 #define CLS_ISCLASS(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_CLASS))
 246
 247 /* The class is initialized within the runtime.  This means that it
 248    has had correct super and sublinks assigned.  */
 249 #define _CLS_RESOLV 0x8L
 250 #define CLS_ISRESOLV(cls) __CLS_ISINFO(cls, _CLS_RESOLV)
 251 #define CLS_SETRESOLV(cls) __CLS_SETINFO(cls, _CLS_RESOLV)
 252
 253 /* The class has been send a +initialize message or a such is not
 254    defined for this class.  */
 255 #define _CLS_INITIALIZED 0x04L
 256 #define CLS_ISINITIALIZED(cls) __CLS_ISINFO(cls, _CLS_INITIALIZED)
 257 #define CLS_SETINITIALIZED(cls) __CLS_SETINFO(cls, _CLS_INITIALIZED)
 258
 259 /* The class is being constructed; it has been allocated using
 260    objc_allocateClassPair(), but has not been registered yet by using
 261    objc_registerClassPair().  This means it is possible to freely add
 262    instance variables to the class, but it can't be used for anything
 263    yet.  */
 264 #define _CLS_IN_CONSTRUCTION 0x10L
 265 #define CLS_IS_IN_CONSTRUCTION(cls) __CLS_ISINFO(cls, _CLS_IN_CONSTRUCTION)
 266 #define CLS_SET_IN_CONSTRUCTION(cls) __CLS_SETINFO(cls, _CLS_IN_CONSTRUCTION)
 267 #define CLS_SET_NOT_IN_CONSTRUCTION(cls) __CLS_SETNOTINFO(cls, _CLS_IN_CONSTRUCTION)
 268
 269 /* The class number of this class.  This must be the same for both the
 270    class and its meta class object.  */
 271 #define CLS_GETNUMBER(cls) (__CLS_INFO(cls) >> (HOST_BITS_PER_LONG/2))
 272 #define CLS_SETNUMBER(cls, num) \
 273   ({ (cls)->info <<= (HOST_BITS_PER_LONG/2); \
 274      (cls)->info >>= (HOST_BITS_PER_LONG/2); \
 275      __CLS_SETINFO(cls, (((unsigned long)num) << (HOST_BITS_PER_LONG/2))); })
 276
 277
 278 /* The compiler generates one of these structures for each category.
 279    A class may have many categories and contain both instance and
 280    factory methods.  */
 281 struct objc_category
 282 {
 283   const char*   category_name;                /* Name of the category.
 284                                                  Name contained in the
 285                                                  () of the category
 286                                                  definition.  */
 287   const char*   class_name;                   /* Name of the class to
 288                                                  which the category
 289                                                  belongs.  */
 290   struct objc_method_list  *instance_methods; /* Linked list of
 291                                                  instance methods
 292                                                  defined in the
 293                                                  category. NULL
 294                                                  indicates no instance
 295                                                  methods defined.  */
 296   struct objc_method_list *class_methods;     /* Linked list of
 297                                                  factory methods
 298                                                  defined in the
 299                                                  category.  NULL
 300                                                  indicates no class
 301                                                  methods defined.  */
 302   struct objc_protocol_list *protocols;       /* List of Protocols
 303                                                  conformed to.  */
 304 };
 305
 306 #endif /* __objc_private_module_abi_8_INCLUDE_GNU */