[SR-3933] Compact Mangling: Investigate mangling based on a known overload set for non-resilient functions

[ematejska]

Previous ID	SR-3933
Radar	rdar://problem/31411222
Original Reporter	@ematejska
Type	Bug
Status	Resolved
Resolution	Won't Do

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, AffectsABI
Assignee	None
Priority	Medium

md5: 165ca59af797880aa304710d5acacfc3

Issue Description:

Ahead of ABI Stability, investigate mangling based on a known overload set for non-resilient functions.

[bob-wilson]

@swift-ci create

[bob-wilson]

There were some discussions about this possibility, but at this point, we are not planning to pursue it. This would be a fairly disruptive change, since you would no longer be able to mangle/demangle a symbol in isolation and the mangling for a function could change when new overloaded functions are added. After the mangling changes in Swift 4.0, the length of our mangled symbol names is looking pretty good and we don't need to attempt heroic measures to shrink them further.