cmd/compile: enable mid-stack inlining

[davidlazar]

Design doc: https://golang.org/design/19348-midstack-inlining

[gopherbot]

CL https://golang.org/cl/37231 mentions this issue.

[gopherbot]

CL https://golang.org/cl/37233 mentions this issue.

[JayNakrani]

This is awesome.

I probably missed some discussion, but is there a design doc or proposal doc I can look at?

Out of curiosity, is there a plan to emit this information as part of DWARF? It would be a nice feature if debuggers can access the InlTree info (right now they can't print correct backtraces for inlined calls; I confirmed with 781fd39).

[davidlazar]

There is an outdated proposal doc. I'll update and publish it this week. In the meantime, these slides give an overview of the approach: https://golang.org/s/go19inliningtalk

I haven't looked at the DWARF yet, but the plan is to add inlining info to the DWARF tables before we turn on mid-stack inlining for 1.9.

[gopherbot]

CL https://golang.org/cl/37854 mentions this issue.

[gopherbot]

CL https://golang.org/cl/38090 mentions this issue.

[rsc]

It seems clear we're going to do this, assuming the right tuning (not yet done!). The tuning itself doesn't have to go through the proposal process. Accepting proposal.