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/* Definitions of Module Structures used by ABI version 8
Copyright (C) 1993-2021 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<>. */
#ifndef __objc_private_module_abi_8_INCLUDE_GNU
#define __objc_private_module_abi_8_INCLUDE_GNU
/* For every class which happens to have statically allocated instances in
this module, one OBJC_STATIC_INSTANCES is allocated by the compiler.
INSTANCES is NULL terminated and points to all statically allocated
instances of this class. */
struct objc_static_instances
char *class_name;
#ifdef __cplusplus
id instances[1];
id instances[0];
/* Whereas a Module (defined further down) is the root (typically) of a file,
a Symtab is the root of the class and category definitions within the
A Symtab contains a variable length array of pointers to classes and
categories defined in the module. */
struct objc_symtab
unsigned long sel_ref_cnt; /* Unused (always set to 0). */
struct objc_selector *refs; /* The table of selectors referenced in
this module. This is terminated by a
selector with NULL sel_id and NULL
sel_types. Note that we use the type
'struct objc_selector *' and not
'SEL' (which is 'const struct
objc_selector *') because the sel_id
of these selectors is patched up by
the runtime when the module is
loaded. */
unsigned short cls_def_cnt; /* Number of classes compiled (defined)
in the module. */
unsigned short cat_def_cnt; /* Number of categories compiled
(defined) in the module. */
void *defs[1]; /* Variable array of pointers.
cls_def_cnt of type Class followed by
cat_def_cnt of type Category_t,
followed by a NULL terminated array
of objc_static_instances. */
/* The compiler generates one of these structures for each module that
composes the executable (eg main.m).
This data structure is the root of the definition tree for the
A collect program runs between ld stages and creates a ObjC ctor
array. That array holds a pointer to each module structure of the
executable. */
struct objc_module
unsigned long version; /* Version of the Module data
structure. */
unsigned long size; /* sizeof(Module) according to the
compiler - only used to sanity check
that it matches sizeof(Module)
according to the runtime. */
const char* name; /* Name of the file used to compile the
module - not set by modern compilers
for security reasons. */
struct objc_symtab *symtab; /* Pointer to the Symtab of the module.
The Symtab holds an array of pointers
to the classes and categories defined
in the module. */
/* The compiler generates one of these structures for a class that has
instance variables defined in its specification. */
struct objc_ivar
const char* ivar_name; /* Name of the instance variable as entered
in the class definition. */
const char* ivar_type; /* Description of the Ivar's type. Useful
for debuggers. */
int ivar_offset; /* Byte offset from the base address of the
instance structure to the variable. */
struct objc_ivar_list
int ivar_count; /* Number of structures (Ivar)
contained in the list. One
structure per instance variable
defined in the class. */
struct objc_ivar ivar_list[1]; /* Variable length structure. */
/* The compiler generates one (or more) of these structures for a
class that has methods defined in its specification.
The implementation of a class can be broken into separate pieces in
a file and categories can break them across modules. To handle this
problem is a singly linked list of methods. */
struct objc_method
SEL method_name; /* This variable is the method's name.
The compiler puts a char* here, and
it's replaced by a real SEL at runtime
when the method is registered. */
const char* method_types; /* Description of the method's parameter
list. Used when registering the
selector with the runtime. When that
happens, method_name will contain the
method's parameter list. */
IMP method_imp; /* Address of the method in the
executable. */
struct objc_method_list
struct objc_method_list* method_next; /* This variable is used to
link a method list to
another. It is a singly
linked list. */
int method_count; /* Number of methods defined
in this structure. */
struct objc_method method_list[1]; /* Variable length
structure. */
/* Note that a 'struct objc_method_description' as embedded inside a
Protocol uses the same trick as a 'struct objc_method': the
method_name is a 'char *' according to the compiler, who puts the
method name as a string in there. At runtime, the selectors need
to be registered, and the method_name then becomes a SEL. */
struct objc_method_description_list
int count;
struct objc_method_description list[1];
struct objc_protocol {
struct objc_class* class_pointer;
char *protocol_name;
struct objc_protocol_list *protocol_list;
struct objc_method_description_list *instance_methods, *class_methods;
struct objc_protocol_list
struct objc_protocol_list *next;
size_t count;
struct objc_protocol *list[1];
The compiler generates one of these structures for each class.
This structure is the definition for classes.
This structure is generated by the compiler in the executable and
used by the run-time during normal messaging operations. Therefore
some members change type. The compiler generates "char* const" and
places a string in the following member variables: super_class.
struct objc_class {
struct objc_class* class_pointer; /* Pointer to the class's meta
class. */
struct objc_class* super_class; /* Pointer to the super
class. NULL for class
Object. */
const char* name; /* Name of the class. */
long version; /* Unknown. */
unsigned long info; /* Bit mask. See class masks
defined below. */
long instance_size; /* Size in bytes of the class.
The sum of the class
definition and all super
class definitions. */
#ifdef _WIN64
/* We pad the structure manually to prevent warning when -Wpadded is
used. The compiler automatically pads the structures that it
generates, so this manually padded structure still matches the
one generated by the compiler, but if we don't pad manually,
-Wpadded detects that padding is being added and generates
annoying warnings. This hack is necessary as on LLP64 targets
sizeof (long) isn't equal to sizeof (void *). */
long pad;
struct objc_ivar_list* ivars; /* Pointer to a structure that
describes the instance
variables in the class
definition. NULL indicates
no instance variables.
Does not include super
class variables. */
struct objc_method_list* methods; /* Linked list of instance
methods defined for the
class. */
struct sarray * dtable; /* Pointer to instance method
dispatch table. */
struct objc_class* subclass_list; /* Subclasses */
struct objc_class* sibling_class;
struct objc_protocol_list *protocols; /* Protocols conformed to */
void* gc_object_type;
/* This is used to assure consistent access to the info field of
classes. */
# define HOST_BITS_PER_LONG (sizeof(long)*8)
#define __CLS_INFO(cls) ((cls)->info)
#define __CLS_ISINFO(cls, mask) ((__CLS_INFO(cls)&mask)==mask)
#define __CLS_SETINFO(cls, mask) (__CLS_INFO(cls) |= mask)
#define __CLS_SETNOTINFO(cls, mask) (__CLS_INFO(cls) &= ~mask)
/* The structure is of type MetaClass */
#define _CLS_META 0x2L
#define CLS_ISMETA(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_META))
/* The structure is of type Class */
#define _CLS_CLASS 0x1L
#define CLS_ISCLASS(cls) ((cls)&&__CLS_ISINFO(cls, _CLS_CLASS))
/* The class is initialized within the runtime. This means that it
has had correct super and sublinks assigned. */
#define _CLS_RESOLV 0x8L
/* The class has been send a +initialize message or a such is not
defined for this class. */
#define _CLS_INITIALIZED 0x04L
/* The class is being constructed; it has been allocated using
objc_allocateClassPair(), but has not been registered yet by using
objc_registerClassPair(). This means it is possible to freely add
instance variables to the class, but it can't be used for anything
yet. */
/* The class number of this class. This must be the same for both the
class and its meta class object. */
#define CLS_GETNUMBER(cls) (__CLS_INFO(cls) >> (HOST_BITS_PER_LONG/2))
#define CLS_SETNUMBER(cls, num) \
({ (cls)->info <<= (HOST_BITS_PER_LONG/2); \
(cls)->info >>= (HOST_BITS_PER_LONG/2); \
__CLS_SETINFO(cls, (((unsigned long)num) << (HOST_BITS_PER_LONG/2))); })
/* The compiler generates one of these structures for each category.
A class may have many categories and contain both instance and
factory methods. */
struct objc_category
const char* category_name; /* Name of the category.
Name contained in the
() of the category
definition. */
const char* class_name; /* Name of the class to
which the category
belongs. */
struct objc_method_list *instance_methods; /* Linked list of
instance methods
defined in the
category. NULL
indicates no instance
methods defined. */
struct objc_method_list *class_methods; /* Linked list of
factory methods
defined in the
category. NULL
indicates no class
methods defined. */
struct objc_protocol_list *protocols; /* List of Protocols
conformed to. */
#endif /* __objc_private_module_abi_8_INCLUDE_GNU */