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623637646/Swift内存规律

Created May 7, 2020 06:24
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Swift中，一个类实例的内存布局是有规律的.
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Swift内存规律
Swift中，一个类实例的内存布局是有规律的：
1. 32位机器上，类前面有4+8个字节存储meta信息，64位机器上，有8+8个字节；
2. 内存中，字段从前往后有序排列；
3. 如果该类继承自某一个类，那么父类的字段在前；
4. Optional会增加一个字节来存储.None/.Some信息；
5. 每个字段需要考虑内存对齐；
这方面尚未从官方的资料找到参考，上述规律一些是从网上其他大神的总结中收集，一些从Clang的一些说明文档中挖掘，加上自己的反复验证得到。
Refer to: https://www.jianshu.com/p/eac4a92b44ef
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