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401 lines
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C

#include <stdlib.h>
#include <assert.h>
#include "objc/runtime.h"
#include "objc/objc-auto.h"
#include "objc/objc-arc.h"
#include "lock.h"
#include "loader.h"
#include "visibility.h"
#include "legacy.h"
#ifdef ENABLE_GC
#include <gc/gc.h>
#endif
#include <stdio.h>
#include <string.h>
/**
* Runtime lock. This is exposed in
*/
PRIVATE mutex_t runtime_mutex;
LEGACY void *__objc_runtime_mutex = &runtime_mutex;
void init_alias_table(void);
void init_arc(void);
void init_class_tables(void);
void init_dispatch_tables(void);
void init_gc(void);
void init_protocol_table(void);
void init_selector_tables(void);
void init_trampolines(void);
void init_early_blocks(void);
void objc_send_load_message(Class class);
void log_selector_memory_usage(void);
static void log_memory_stats(void)
{
log_selector_memory_usage();
}
/* Number of threads that are alive. */
int __objc_runtime_threads_alive = 1; /* !T:MUTEX */
// libdispatch hooks for registering threads
__attribute__((weak)) void (*dispatch_begin_thread_4GC)(void);
__attribute__((weak)) void (*dispatch_end_thread_4GC)(void);
__attribute__((weak)) void *(*_dispatch_begin_NSAutoReleasePool)(void);
__attribute__((weak)) void (*_dispatch_end_NSAutoReleasePool)(void *);
__attribute__((used))
static void link_protos(void)
{
link_protocol_classes();
}
static void init_runtime(void)
{
static BOOL first_run = YES;
if (first_run)
{
#if ENABLE_GC
init_gc();
#endif
// Create the main runtime lock. This is not safe in theory, but in
// practice the first time that this function is called will be in the
// loader, from the main thread. Future loaders may run concurrently,
// but that is likely to break the semantics of a lot of languages, so
// we don't have to worry about it for a long time.
//
// The only case when this can potentially go badly wrong is when a
// pure-C main() function spawns two threads which then, concurrently,
// call dlopen() or equivalent, and the platform's implementation of
// this does not perform any synchronization.
INIT_LOCK(runtime_mutex);
// Create the various tables that the runtime needs.
init_selector_tables();
init_dispatch_tables();
init_protocol_table();
init_class_tables();
init_alias_table();
init_early_blocks();
init_arc();
init_trampolines();
first_run = NO;
if (getenv("LIBOBJC_MEMORY_PROFILE"))
{
atexit(log_memory_stats);
}
if (dispatch_begin_thread_4GC != 0) {
dispatch_begin_thread_4GC = objc_registerThreadWithCollector;
}
if (dispatch_end_thread_4GC != 0) {
dispatch_end_thread_4GC = objc_unregisterThreadWithCollector;
}
if (_dispatch_begin_NSAutoReleasePool != 0) {
_dispatch_begin_NSAutoReleasePool = objc_autoreleasePoolPush;
}
if (_dispatch_end_NSAutoReleasePool != 0) {
_dispatch_end_NSAutoReleasePool = objc_autoreleasePoolPop;
}
}
}
/**
* Structure for a class alias.
*/
struct objc_alias
{
/**
* The name by which this class is referenced.
*/
const char *alias_name;
/**
* A pointer to the indirection variable for this class.
*/
Class *alias;
};
/**
* Type of the NSConstantString structure.
*/
struct nsstr
{
/** Class pointer. */
id isa;
/**
* Flags. Low 2 bits store the encoding:
* 0: ASCII
* 1: UTF-8
* 2: UTF-16
* 3: UTF-32
*
* Low 16 bits are reserved for the compiler, high 32 bits are reserved for
* the Foundation framework.
*/
uint32_t flags;
/**
* Number of UTF-16 code units in the string.
*/
uint32_t length;
/**
* Number of bytes in the string.
*/
uint32_t size;
/**
* Hash (Foundation framework defines the hash algorithm).
*/
uint32_t hash;
/**
* Character data.
*/
const char *data;
};
// begin: objc_init
struct objc_init
{
uint64_t version;
SEL sel_begin;
SEL sel_end;
Class *cls_begin;
Class *cls_end;
Class *cls_ref_begin;
Class *cls_ref_end;
struct objc_category *cat_begin;
struct objc_category *cat_end;
struct objc_protocol *proto_begin;
struct objc_protocol *proto_end;
struct objc_protocol **proto_ref_begin;
struct objc_protocol **proto_ref_end;
struct objc_alias *alias_begin;
struct objc_alias *alias_end;
struct nsstr *strings_begin;
struct nsstr *strings_end;
};
// end: objc_init
#ifdef DEBUG_LOADING
#include <dlfcn.h>
#endif
static enum {
LegacyABI,
NewABI,
UnknownABI
} CurrentABI = UnknownABI;
void registerProtocol(Protocol *proto);
OBJC_PUBLIC void __objc_load(struct objc_init *init)
{
init_runtime();
#ifdef DEBUG_LOADING
Dl_info info;
if (dladdr(init, &info))
{
fprintf(stderr, "Loading %p from object: %s (%p)\n", init, info.dli_fname, __builtin_return_address(0));
}
else
{
fprintf(stderr, "Loading %p from unknown object\n", init);
}
#endif
LOCK_RUNTIME_FOR_SCOPE();
BOOL isFirstLoad = NO;
switch (CurrentABI)
{
case LegacyABI:
fprintf(stderr, "Version 2 Objective-C ABI may not be mixed with earlier versions.\n");
abort();
case UnknownABI:
isFirstLoad = YES;
CurrentABI = NewABI;
break;
case NewABI:
break;
}
// If we've already loaded this module, don't load it again.
if (init->version == ULONG_MAX)
{
return;
}
assert(init->version == 0);
assert((((uintptr_t)init->sel_end-(uintptr_t)init->sel_begin) % sizeof(*init->sel_begin)) == 0);
assert((((uintptr_t)init->cls_end-(uintptr_t)init->cls_begin) % sizeof(*init->cls_begin)) == 0);
assert((((uintptr_t)init->cat_end-(uintptr_t)init->cat_begin) % sizeof(*init->cat_begin)) == 0);
for (SEL sel = init->sel_begin ; sel < init->sel_end ; sel++)
{
if (sel->name == 0)
{
continue;
}
objc_register_selector(sel);
}
for (struct objc_protocol *proto = init->proto_begin ; proto < init->proto_end ;
proto++)
{
if (proto->name == NULL)
{
continue;
}
registerProtocol((struct objc_protocol*)proto);
}
for (struct objc_protocol **proto = init->proto_ref_begin ; proto < init->proto_ref_end ;
proto++)
{
if (*proto == NULL)
{
continue;
}
struct objc_protocol *p = objc_getProtocol((*proto)->name);
assert(p);
*proto = p;
}
for (Class *cls = init->cls_begin ; cls < init->cls_end ; cls++)
{
if (*cls == NULL)
{
continue;
}
// As a special case, allow using legacy ABI code with a new runtime.
if (isFirstLoad && (strcmp((*cls)->name, "Protocol") == 0))
{
CurrentABI = UnknownABI;
}
#ifdef DEBUG_LOADING
fprintf(stderr, "Loading class %s\n", (*cls)->name);
#endif
objc_load_class(*cls);
}
#if 0
// We currently don't do anything with these pointers. They exist to
// provide a level of indirection that will permit us to completely change
// the `objc_class` struct without breaking the ABI (again)
for (Class *cls = init->cls_ref_begin ; cls < init->cls_ref_end ; cls++)
{
}
#endif
for (struct objc_category *cat = init->cat_begin ; cat < init->cat_end ;
cat++)
{
if ((cat == NULL) || (cat->class_name == NULL))
{
continue;
}
objc_try_load_category(cat);
#ifdef DEBUG_LOADING
fprintf(stderr, "Loading category %s (%s)\n", cat->class_name, cat->name);
#endif
}
// Load categories and statics that were deferred.
objc_load_buffered_categories();
// Fix up the class links for loaded classes.
objc_resolve_class_links();
for (struct objc_category *cat = init->cat_begin ; cat < init->cat_end ;
cat++)
{
Class class = (Class)objc_getClass(cat->class_name);
if ((Nil != class) &&
objc_test_class_flag(class, objc_class_flag_resolved))
{
objc_send_load_message(class);
}
}
// Register aliases
for (struct objc_alias *alias = init->alias_begin ; alias < init->alias_end ;
alias++)
{
if (alias->alias_name)
{
class_registerAlias_np(*alias->alias, alias->alias_name);
}
}
#if 0
// If future versions of the ABI need to do anything with constant strings,
// they may do so here.
for (struct nsstr *string = init->strings_begin ; string < init->strings_end ;
string++)
{
if (string->isa)
{
}
}
#endif
init->version = ULONG_MAX;
}
#ifdef OLDABI_COMPAT
OBJC_PUBLIC void __objc_exec_class(struct objc_module_abi_8 *module)
{
init_runtime();
switch (CurrentABI)
{
case UnknownABI:
CurrentABI = LegacyABI;
break;
case LegacyABI:
break;
case NewABI:
fprintf(stderr, "Version 2 Objective-C ABI may not be mixed with earlier versions.\n");
abort();
}
// Check that this module uses an ABI version that we recognise.
// In future, we should pass the ABI version to the class / category load
// functions so that we can change various structures more easily.
assert(objc_check_abi_version(module));
// The runtime mutex is held for the entire duration of a load. It does
// not need to be acquired or released in any of the called load functions.
LOCK_RUNTIME_FOR_SCOPE();
struct objc_symbol_table_abi_8 *symbols = module->symbol_table;
// Register all of the selectors used in this module.
if (symbols->selectors)
{
objc_register_selector_array(symbols->selectors,
symbols->selector_count);
}
unsigned short defs = 0;
// Load the classes from this module
for (unsigned short i=0 ; i<symbols->class_count ; i++)
{
objc_load_class(objc_upgrade_class(symbols->definitions[defs++]));
}
unsigned int category_start = defs;
// Load the categories from this module
for (unsigned short i=0 ; i<symbols->category_count; i++)
{
objc_try_load_category(objc_upgrade_category(symbols->definitions[defs++]));
}
// Load the static instances
struct objc_static_instance_list **statics = (void*)symbols->definitions[defs];
while (NULL != statics && NULL != *statics)
{
objc_init_statics(*(statics++));
}
// Load categories and statics that were deferred.
objc_load_buffered_categories();
objc_init_buffered_statics();
// Fix up the class links for loaded classes.
objc_resolve_class_links();
for (unsigned short i=0 ; i<symbols->category_count; i++)
{
struct objc_category *cat = (struct objc_category*)
symbols->definitions[category_start++];
Class class = (Class)objc_getClass(cat->class_name);
if ((Nil != class) &&
objc_test_class_flag(class, objc_class_flag_resolved))
{
objc_send_load_message(class);
}
}
}
#endif