lto gimple types and debug info

[Mark Mitchell]

Daniel Berlin wrote:

> Then again, I also don't see what the big deal about adding a debug
> info parser is.

OK, yes, we may need to read debug info back in.

I don't see it as a big deal, either -- and I also don't see it as 
locking us into DWARF2.  We can presumably read in any formats we are 
about, so if we want to add a stabs reader, we can do that to support 
stabs platforms.  And, until we have a stabs reader, we can just drop 
debug info on those platforms when doing LTO.  So, we just have to 
design LTO with some abstraction over debug info in mind.

In fact, we could probably treat DWARF as canonical, and have a 
STABS->DWARF input filter and DWARF->STABS output filter, if we like.

I'm not hung up on the exact implementation; all I'm trying to do is 
address the idea that somehow we're going to make it impossible for LTO 
to work with non-DWARF debug info.  As long as it we design it 
carefully, there's no reason we should have that limitation.

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713