Hacking the Go compiler to efficiently map IPv4 to IPv6
7 relevance
Score Breakdown
technical depth 9
novelty 8
actionability 5
community 5
strategic 5
personal 7
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Deep technical hack on Go compiler for network mapping, relevant to infrastructure.
Summary
netip.Addr features an Unmap() method returning the unwrapped IPv4 contained in an IPv4-mapped IPv6 address : from ::ffff:203.0.113.10 or ::ffff:cb00:710a , it returns 203.0.113.10 . 1 There is no Map() or To6() method for the reverse direction. Such a method is trivial to implement, but Go maintainers have rejected it on the grounds that users should write netip.AddrFrom16(ip.As16()) and let the compiler optimize it. 2 Today, this pattern is eight times slower than a native method. How can we teach the compiler to optimize this sequence?
Author
Vincent Bernat