Windows on ARM is always thumb, and contrary to ELF, there's no per-symbol flag to indicate arm vs thumb mode. Therefore, the linkers both Microsoft's link.exe and lld) sets the thumb bit in all relocations pointing to code sections.
In ELF, the thumb bit is only set for symbols marked as %function, that is, it isn't set in local labels used when constructing the dwarf debug info and line tables.
As the windows linkers sets the thumb bit in all code addresses, we'd have to cope with this and strip out the lowest bit from all code addresses if the architecture is ARM/Thumb.
There's already predecent for this in DWARFCallFrameInfo::GetFDEIndex, this extends the same concept to DWARF debug info and line tables. I'm not sure if I managed to get all spots covered here, but I tried to look for all cases of DW_AT_low_pc/DW_AT_high_pc and find the best place to handle it, where it would have to be handled in as few places as possible.
This is admittedly not very pretty, improvement suggestions are welcome.