MJXin

附录-OC源码-Runtime：探究源码中的宏

  • Jul 01, 2020
  • 0 views
  • __ARM_ARCH_7K__ : 0 ( iPhone 64 真机推测值)
    参考文章,未证实的出处: 浅尝 objc_msgSend </mark> :iBlog
    ARM 7k 架构 CPU 的代码中的标志宏 
    // ARM.cpp  
// Unfortunately, __ARM_ARCH_7K__ is now more of an ABI descriptor. The CPU  
// happens to be Cortex-A7 though, so it should still get __ARM_ARCH_7A__.  
if (getTriple().isWatchABI())  
Builder.defineMacro("__ARM_ARCH_7K__", "2");

    影响:

    • objc-config.h - SUPPORT_INDEXED_ISA

  • __arm64__ : 1 ( iPhone 64 真机运行值)
    参考文章, 未查源码出处
    ARM 64 架构宏
    影响:
    • objc-config.h - SUPPORT_INDEXED_ISA

  • __LP64__ : 1 ( iPhone 64 真机运行值)
    参考文章, 未查源码出处 编译器中和64位编程有关的预定义宏_liangbch的专栏-CSDN博客
    Linux 64 位宏,代表 long 和 pointer 为 64 位
    影响:
    • objc-config.h - SUPPORT_INDEXED_ISA

  • SUPPORT_INDEXED_ISA : 0 ( iPhone 64 推测值) 
    // objc-object.h  
#if __ARM_ARCH_7K__ >= 2  ||  (__arm64__ && !__LP64__)  
#   define SUPPORT_INDEXED_ISA 1  
#else  
#   define SUPPORT_INDEXED_ISA 0  
#endif

    影响:

    • objc-object.h - objc_object<mark>ISA()

  • SUPPORT_PACKED_ISA : 1 ( iPhone 64 推测值)
    • TARGET_OS_WIN32, TARGET_OS_SIMULATOR 打印都是 0, 直面意思理解,不细究 
      // objc-object.h  
#if (!__LP64__  ||  TARGET_OS_WIN32  ||  \  
   (TARGET_OS_SIMULATOR && !TARGET_OS_IOSMAC))  
#   define SUPPORT_PACKED_ISA 0  
#else  
#   define SUPPORT_PACKED_ISA 1  
#endif


  • SUPPORT_NONPOINTER_ISA : 1 ( iPhone 64 推测值) 
    // objc-object.h  
#if !SUPPORT_INDEXED_ISA  &&  !SUPPORT_PACKED_ISA  
#   define SUPPORT_NONPOINTER_ISA 0  
#else  
#   define SUPPORT_NONPOINTER_ISA 1  
#endif

    影响: struct objc_object中诸多函数的真正实现

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