简介

OC的一个主要特性Runtime运行时特性，在日常开发中我们使用到的都是不可见的，还好官方提供了 Runtime（objc4） 源码供开发者研究，我是 ZJ，下面就开始迈出源码探索的第一步，源码编译。

下载objc4-781

进入源码区

打开源码链接

选择 macOS ，搜索 objc4- ，然后下载到桌面

首先编译 target objc

unable to find sdk ‘macosx.internal’

解决办法：

PROJECTS –> objc –> Build Settings, 将 Base SDK 改成 macOS

TARGETS –> objc –> Build Settings, 将 Base SDK 改成 macOS

‘sys/reason.h’ file not found

解决办法：

还是在 macOS 目录下，下载 xnu-8020.101.41, 把 xnu-8020.101.41/bsd/sys/reason.h 文件复制到桌面创建的新文件夹 comm_ifl/sys 目录下

将文件 ZJCommon 放在工程根目录下，并在工程设置文件的索引路径

target -> objc -> Build Settings -> Header Search Paths -> 添加 $(SRCROOT)/ZJCommon

注释错误可以最后再弄

Unknown type name ‘uint32_t’

添加 #include <stdint.h>

‘mach-o/dyld_priv.h’ file not found

原理同上，下载 dyld-960 文件，将 dyld_priv.h 文件，拷贝到 comm_ifl/mach-o/dyld_priv.h 下

‘os/lock_private.h’ file not found

原理同上，下载 libplatform-273.100.5 文件，将 libplatform-273.100.5/private/os/lock_private.h 中 lock_private.h 文件，拷贝到 comm_ifl/os/lock_private.h 下

extern dyld_platform_t dyld_get_active_platform(void) __API_AVAILABLE(macos(10.14), ios(12.0), watchos(5.0), tvos(12.0), bridgeos(3.0)); —- 报错 Expected ‘,’

由于调试主要基于 macos，删除 , bridgeos(3.0)
批量同上均删除 , bridgeos(3.0)

bridgeos(4.0) 问题

去除 , bridgeos(4.0)

‘os/base_private.h’ file not found

在 xnu-8020.101.41/libken/os/base_private.h 中，把 base_private.h 文件，拷贝到 comm_ifl/os/base_private.h

‘pthread/tsd_private.h’ file not found

下载 libpthread-libpthread-486.100.11 文件，将 libpthread-libpthread-486.100.11/private/pthread/tsd_private.h 拷贝到 comm_ifl/pthread/tsd_private.h

‘os/feature_private.h’ file not found

注释掉

‘os/variant_private.h’ file not found

拷贝 Libc-Libc-1507.100.9/os/variant_private.h 至 comm_ifl/os/variant_private.h

‘os/tsd.h’ file not found

拷贝 xnu-xnu-8020.101.4/libsyscall/os/tsd.h 至 comm_ifl/os/tsd.h

‘pthread/spinlock_private.h’ file not found

拷贝 libpthread-libpthread-486.100.11/private/pthread/spinlock_private.h 至 comm_ifl/pthread/spinlock_private.h

Expected function body after function declarator

‘System/pthread_machdep.h’ file not found

‘System/pthread_machdep.h’文件只有在Libc-825.40.1及以下版本才有

在 https://opensource.apple.com/source/Libc/Libc-583/pthreads/ 上下载 pthread_machdep.h，拷贝 pthread_machdep.h 至 comm_ifl/System/pthread_machdep.h

‘CrashReporterClient.h’ file not found

在这里下载拷贝 CrashReporterClient.h 至 comm_ifl/CrashReporterClient.h

#include_next<CrashReporterClient.h> 改为
#include <CrashReporterClient.h>

依然报错：在 Build Settings -> Preprocessor Macros 中加入: LIBC_NO_LIBCRASHREPORTERCLIENT

Typedef redefinition with different types (‘int’ vs ‘volatile OSSpinLock’ (aka ‘volatile int’))

注释掉

Unexpected character <U+1F92F>

注释掉

Use of undeclared identifier ‘dyld_platform_version_macOS_10_13’

注释掉

‘os/reason_private.h’ file not found

拷贝 xnu-xnu-8020.101.4/libkern/os/reason_private.h 至 comm_ifl/os/reason_private.h

‘os/bsd.h’ file not found

直接注释

‘objc-shared-cache.h’ file not found

拷贝 dyld-dyld-960/include/objc-shared-cache.h 至 comm_ifl/objc-shared-cache.h

‘os/linker_set.h’ file not found

拷贝 Libc-Libc-1507.100.9/os/linker_set.h 至 comm_ifl/os/linker_set.h

‘_simple.h’ file not found

全局搜索 _simple.h 拷贝至 comm_ifl/_simple.h

Use of undeclared identifier ‘dyld_fall_2020_os_versions’

注释掉

Use of undeclared identifier ‘objc4’

注释掉

Use of undeclared identifier ‘preoptimizedCaches’

注释掉

Use of undeclared identifier ‘CRGetCrashLogMessage’

注释掉

‘Cambria/Traps.h’ file not found 和 ‘Cambria/Cambria.h’ file not found

注释掉

Use of undeclared identifier ‘objc_thread_get_rip’

‘kern/restartable.h’ file not found

xnu-xnu-8020.101.4/osfmk/kern/restartable.h 拷贝到 comm_ifl/kern/restartable.h

Use of undeclared identifier ‘oah_is_current_process_translated’

注释掉

‘Block_private.h’ file not found

libclosure-libclosure-79.1/Block_private.h 拷贝到 comm_ifl/Block_private.h

Use of undeclared identifier ‘os_parse_boot_arg_string’

注释掉

Use of undeclared identifier ‘dyld_platform_version_macOS_10_11’

注释掉

Use of undeclared identifier ‘dyld_fall_2018_os_versions’

Use of undeclared identifier ‘dyld_platform_version_macOS_10_12’

‘_static_assert’ declared as an array with a negative size

注释掉

最后这几步很重要

在 dyld_priv.h 文件顶部加入宏

#define DYLD_MACOSX_VERSION_10_11 0x000A0B00
#define DYLD_MACOSX_VERSION_10_12 0x000A0C00
#define DYLD_MACOSX_VERSION_10_13 0x000A0D00
#define DYLD_MACOSX_VERSION_10_14 0x000A0E00

OC底层原理02：Objc4源码编译

简介