Re: [PATCH 2/2] Ada: Remove debug line number for DECL_IGNORED_P functions

[Richard Biener <rguenther@suse.de>]

On Mon, 9 Aug 2021, Eric Botcazou wrote:

> > But it is okay that we can set a breakpoint on defs__struct1IP,
> > in the test case of PR 101598.
> > And the debugger shall only show assembler here.
> > Right?
> 
> The defs__struct1IP procedure should be totally transparent for the user, so 
> setting a breakpoint in it is not supposed to come into play.
> 
> > Do you have an example where this location information is used in the
> > compiler itself for debugging?
> 
> That's useful when you compile the code with -gnatD, i.e when you debug the 
> intermediate code generated by the front-end.
> 
> > I assume You would agree that having the location for Test2 is better
> > than no debug info at all?
> 
> But we want no debug info at all for these IP functions.
> 
> > What do you think?
> 
> I guess I still don't understand why DECL_IGNORED_P was changed.

ISTR it was changed because at least with location info generated
by gas there's no way to have "no location" for a portion of code.
Instead the assigned location will be that of the previous .loc
directive which results in random and confusing results for the
pc range of the DECL_INGORED_P function.

I guess we should really revisit the decision to rely on gas
to produce line info.  What's the advantage of doing so (apart
from "nice" annotated assembly)?

Richard.