[Dwarf-Discuss] debug_names - what should go in ?

[David Blaikie]

That's good to know - thanks Jim!

Pavel, for unnamed using directives/declarations - why would you need to
add the name to the index, shouldn't it already be in the index (if the
index contains unqualified names) from its original location/definition?

On Tue, Apr 10, 2018 at 10:44 AM Jim Ingham via Dwarf-Discuss <
dwarf-discuss at lists.dwarfstd.org> wrote:

> This is certainly how lldb treats the Apple names and types indexes.  If
> present, we don't do any indexing of DWARF, we just use the indexes, and of
> course any local context.
>
> Enums have been a long-standing problem with this approach, the Apple
> indices only mention the enum type, so you can't use them in expressions in
> they way you would type them in code.  It would be nice to fix that.
>
> Jim
>
>
> > On Apr 10, 2018, at 10:37 AM, Eric Christopher via Dwarf-Discuss <
> dwarf-discuss at lists.dwarfstd.org> wrote:
> >
> > I have nothing to add to what Paul just said :)
> >
> > This is definitely the intent and what we should do.
> >
> > -eric
> >
> > On Tue, Apr 10, 2018 at 10:26 AM Paul Robinson via Dwarf-Discuss <
> dwarf-discuss at lists.dwarfstd.org> wrote:
> > The intent of the index is given pretty plainly in the non-normative
> text at the bottom of p.137; you should be able to look up any unqualified
> name in the index.  If the normative text doesn't accomplish that, we have
> an opportunity to improve the spec. J
> >
> >
> >
> > FWIW here's my take:
> >
> >
> >
> > Enumerations are a bit unusual in that the enumerators are children of
> the enumeration type, but the enumerator names are not qualified by the
> type name (usually?a C++ enum-class should not put enumerators into the
> index, I think).  But you need some rule that excludes enumerations that
> are not otherwise "global" (e.g., they are contained in a class or local to
> a function).
> >
> >
> >
> > For imported entities, I'd say if the imported entity would have
> satisfied the criteria for inclusion in the index if it had been "inlined"
> at the point where it was imported, then it ought to be in the index.
> >
> > --paulr
> >
> >
> >
> >
> >
> > From: Dwarf-Discuss [mailto:dwarf-discuss-bounces at lists.dwarfstd.org]
> On Behalf Of David Blaikie via Dwarf-Discuss
> > Sent: Tuesday, April 10, 2018 12:30 PM
> > To: Pavel Labath
> > Cc: dwarf-discuss at lists.dwarfstd.org
> > Subject: Re: [Dwarf-Discuss] debug_names - what should go in ?
> >
> >
> >
> > Yep - sounds like it to me.
> >
> > I suppose, arguably, one could say that successful name lookups of
> things in the index can be fast, while lookups that fail, or find names not
> in the index may be slow - but that seems unacceptable to me (in many cases
> "slow" would be "prohibitively slow" especially the first time - since it'd
> amount to the non-index case: the consumer having to build its own index
> from scratch)
> >
> > Maybe Adrian or Eric can talk to how the Apple indexes worked in these
> cases.
> >
> >
> >
> > On Tue, Apr 10, 2018 at 9:24 AM Pavel Labath <labath at google.com> wrote:
> >
> > On Tue, 10 Apr 2018 at 16:44, David Blaikie <dblaikie at gmail.com> wrote:
> >
> > I'd say any case where a consumer couldn't actually rely on the table to
> do name resolution would be a bug - or at least something that needs to be
> seriously considered/discussed/figured out how the name table can be used
> in those situations.
> >
> >
> >
> > Agreed.
> >
> >
> >
> > This question can be demonstrated on a simple c++ program
> >
> > ============
> >
> > namespace namesp1 { int var; }
> >
> > namespace namesp2 = namesp1; // DW_TAG_imported_declaration
> >
> >
> >
> > enum enum_type { enumerator }; // DW_TAG_enumeration_type,
> DW_TAG_enumerator
> >
> >
> >
> > int main() {
> >
> >   return namesp2::var + enumerator;
> >
> > }
> >
> > ============
> >
> >
> >
> > Debugging with gdb (without any indexes), the following 4 expressions
> succeed
> >
> > 1) namesp1::var
> >
> > 2) namesp2::var
> >
> > 3) (enum_type)0
> >
> > 4) enumerator
> >
> >
> >
> > The question is how should an index-aware debugger find the entities
> referenced by expressions 2 and 4 if they are not present in the index?
> >
> >
> >
> > They way I see it -- it can't. Which would be a bug in the spec by your
> definition.
> >
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