Steven Bosscher <[EMAIL PROTECTED]> writes: > I haven't really been following the whole LTO thing much, but if I understand > correctly, the goal is to reconstruct information about declarations from > DWARF information that we write out for those declarations. If that's the > case, I wonder how LTO will handle artificial "variables" and formal argument > lists.
I think it is a mistake to focus on DWARF details too much. We simply need some mechanism to write trees into an object file and to read them back in. That mechanism can be anything. We are using DWARF on the theory that it will be simpler because DWARF readers and writers already exist (I don't buy that argument myself, but, whatever). But it is clearly impossible to represent everything we need to represent in DWARF. So we need to extend DWARF as necessary to represent all the tree details. That is, we are not going to write out DWARF. We can't, because DWARF is not designed to represent all the details which the compiler needs to represent. What we are going to write out is a superset of DWARF. And in fact, if it helps, I think that we shouldn't hesitate to write out something which is similar to but incompatible with DWARF. In general reading and writing trees is far from the hardest part of the LTO effort. I think it is a mistake for us to get too tied up in the details of how to represent things in DWARF. (I also think that we could probably do better by defining our own bytecode language, one optimized for our purposes, but it's not an issue worth fighting over.) Ian
