Re: next tasks

[Petr Machata <pmachata at redhat dot com>]

Roland McGrath wrote:
> My sense of the priority order of our tasks at large granularity is this:
> 
> 1. basic writer data structure building (designed for the eventual fancy plans)

What are these "fancy plans"?  DWARF compression (as in zlib) was 
mentioned a couple times, so that might be one (although that would need 
reader support, too, wouldn't it?), anything else?  I expect that the 
"semantic compression" will be built on top of this, as an application 
rather than intrinsic feature of the library.

Also, what level do you want to write the writer on?  C?  There is "C++ 
interface for writer" item on your list of tasks, but it's not clear 
whether C++ is the place where the writer will be implemented, or rather 
a place where it would be wrapped.

I'm thinking that .debug_abbrev is one approach to compression that 
isn't currently held back by absence of reference equality component. 
To do it, one needs to be able to write/modify .debug_info, and that in 
turn requires writing of/modifying .debug_loc, .debug_pub*, and 
.debug_aranges.  A hack that would recompute .debug_aranges and 
.debug_pub* and write them to disk would be sufficient for starters, and 
and I don't think I've seen any DW_OP_call_ref in any of our binaries at 
all.  So we could in fact have something in hand soonish...

PM

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