/***********************************************************************
* _objc_init
* Bootstrap initialization. Registers our image notifier with dyld.
* Called by libSystem BEFORE library initialization time
**********************************************************************/
➜ RyukieDevGitBook git:(master) ✗ export OBJC_HELP=1
objc[57485]: Objective-C runtime debugging. Set variable=YES to enable.
objc[57485]: OBJC_HELP: describe available environment variables
objc[57485]: OBJC_PRINT_OPTIONS: list which options are set
objc[57485]: OBJC_PRINT_IMAGES: log image and library names as they are loaded
objc[57485]: OBJC_PRINT_IMAGE_TIMES: measure duration of image loading steps
objc[57485]: OBJC_PRINT_LOAD_METHODS: log calls to class and category +load methods
objc[57485]: OBJC_PRINT_INITIALIZE_METHODS: log calls to class +initialize methods
...
三、 static_init
调用全局静态C++构造函数
执行全局静态 C++构造函数
libc在 dyld 调用构造函数之前 调用_objc_init()
所以我们要自己处理
/***********************************************************************
* static_init
* Run C++ static constructor functions.
* libc calls _objc_init() before dyld would call our static constructors,
* so we have to do it ourselves.
**********************************************************************/
static void static_init()
{
size_t count;
auto inits = getLibobjcInitializers(&_mh_dylib_header, &count);
for (size_t i = 0; i < count; i++) {
inits[i]();
}
auto offsets = getLibobjcInitializerOffsets(&_mh_dylib_header, &count);
for (size_t i = 0; i < count; i++) {
UnsignedInitializer init(offsets[i]);
init();
}
}
/***********************************************************************
* allocatedClasses
* A table of all classes (and metaclasses) which have been allocated
* with objc_allocateClassPair.
**********************************************************************/
namespace objc {
static ExplicitInitDenseSet<Class> allocatedClasses;
}
