[jcranmer]

> Debuggers already have a terrible user experience when stepping through functions in an optimized executable ; I doubt that reverse-engineered debugging data would be any better.

Actually, I suspect it could be a world of difference. The main failures of optimized debugging are that code motion makes line number tables more of a suggestion, the source code values may disappear in favor of other related values (e.g., SROA or changing A[i] to p++), live ranges of variables may shrink, and debugging information may only support variables in stack slot or other specific locations. If you generating debugging based on decompiled code, you can control the output code to make the first two problems more or less go away, and so you only really have to worry about narrow live ranges (can't do much about that) or debuggers not supporting the features you need (which, given DWARF, is a very real possibility).