Re: debugging info considered harmful to lto.

[Jason Merrill <jason at redhat dot com>]

Jan Hubicka wrote:
> Thanks for explanation - the space optimization seems relatively
> chalenging to implement, in particular because the variables in scope
> might change in between the time abstract copy is output and the time
> the block referencing to the block via abstract pointer is output.

The block is a lexical thing, optimizations don't change that.

> We have origin pointers in declarations and origin pointers in blocks.
> I guess optimization willing to know all variables same from user POV
> (for lets say setting watchpoint on something in inline function)
> probably cares about origins of declarations rather than blocks. 
>
> At what time the blocks actually matters?

So the debugger knows which declarations are in scope at a particular PC.

> For example if I have block that contians just single block and declare
> no new variables, can I simply remove it and replace it by the inner
> block?

Yes.

Jason