debug info for pre-compiled code

[JeffBezanson]

The static compilation process doesn't save all of our debug info. I hope in the near future we will handle this using the DWARF data, but for now we could just dump our table of line numbers and offsets.

For example:

julia> include("notfound")
ERROR: could not open file /home/jeff/src/julia2/julia/notfound

julia> 

After removing sys.so:

julia> include("notfound")
ERROR: could not open file /home/jeff/src/julia2/julia/notfound
 in include at boot.jl:240

julia> 

[jiahao]

Keno/DWARF.jl@b59079a

[ivarne]

This also breaks the helpful message for DomainError for sqrt(-1), because the backtrace does not contain the address of the sqrt function.

[vtjnash]

Presumably, the sys.bc file (and therefore the sys.so file) could contain the file/line number information without doing anything special?

[Keno]

I'm actually not sure why it doesn't. The module still has it just before emitting it. Are we actively stripping debug info somewhere?

[JeffBezanson]

We look for line number info in our own map built by a JIT event listener.

[Keno]

Fair enough, but that doesn't explain why sys.bc doesn't contain any debug info, even though it's in the source module.

[Keno]

I'll have a look at what LLVM gives us.

[vtjnash]

I thought this was already fixed (see for example #5502)

[Keno]

We still don't do it for our own backtraces. We still need to read in the DWARF info.

[ihnorton]

What should be done with the reloaded info? It seems awkward - but possible - to put it back into the JITEvent_EmittedFunctionDetails::LineStart / DebugLoc format. Any other ideas?

[ihnorton]

This is fixed for mac and linux in c77e098. Tabled for now on Windows, see discussion in 6490.