1.12

[changkun]

动机

目前已经发布了 1.12 的 beta1 版本，考虑到 1.12 版本对运行时作出了较多改进，应该
开始准备对内容进行适配。

需求说明

• 1.12 Release Note: https://tip.golang.org/doc/go1.12

• 1.12 Issue tracker: https://github.com/golang/go/milestone/65

• 1.12 vs 1.11 变化对比: https://github.com/changkun/go/pull/4/files

• 相对重要的改进

  • 抢占式调度：runtime: non-cooperative goroutine preemption golang/go#24543
    • 设计文档： https://github.com/golang/proposal/blob/master/design/24543-non-cooperative-preemption.md
  • 并发 GC：runtime: eliminate stack rescanning golang/go#17503
    • 设计文档：https://github.com/golang/proposal/blob/master/design/17503-eliminate-rescan.md
  • 并发 GC：runtime: simplify mark termination and eliminate mark 2 golang/go#26903
    • 设计文档：https://github.com/golang/proposal/blob/master/design/26903-simplify-mark-termination.md
  • Go 程序 ABI : proposal: runtime: make the ABI undefined as a step toward changing it golang/go#27539
    • 设计文档：https://github.com/golang/proposal/blob/master/design/27539-internal-abi.md

• 比较重要的 bug:

  • 并发 GC 的问题：runtime: error message: P has cached GC work at end of mark termination golang/go#27993
  • 编译器残留内存：cmd/compile: compiler can unexpectedly preserve memory golang/go#22350
    • 设计文档：https://docs.google.com/document/d/1un-Jn47yByHL7I0aVIP_uVCMxjdM5mpelJhiKlIqxkE/edit#

[changkun]

目前已经完成的正文与对应代码均已同步到 go1.12beta2，故可将剩余的写作任务转移到 #1 中，关闭此 issue。