Re: [Dwarf Fission] Implement Fission Proposal (issue6305113)

[Jason Merrill <jason at redhat dot com>]

On 10/10/2012 08:41 PM, Cary Coutant wrote:
> I'm working on a follow-up patch to eliminate the duplicate references
> to ".LVL" symbols by keeping a direct-lookup table in
> dwarf2out_var_location. That will eliminate 310,266 of the 312,061
> duplicates (99.4%) without using a hash table. With that patch, we'll
> have only a 22% overhead due to duplicate entries.

That's certainly a big improvement, but 22% still seems worth addressing.

> I'm trying to eliminate all .debug_addr entries that could be replaced
> by an offset relative to either another .debug_addr entry or an
> address in a range list.

Sounds good.

> We use force_direct when we're adding an attribute to a DIE in a
> skeleton compile unit or type unit (which will be in the .o file).
> It's false everywhere else (i.e., when the DIE is going into the .dwo
> file).

Right, so I was thinking that you could distinguish at output time 
between output going to .o vs .dwo and choose the appropriate addressing 
form then.

Jason