[PATCH] D36993: [llvm-dwarfdump] Print type names in DW_AT_type DIEs

[David Blaikie via llvm-commits]

On Fri, Sep 1, 2017 at 1:41 PM Adrian Prantl <aprantl at apple.com> wrote:

> On Sep 1, 2017, at 1:36 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
> Could we get reasonable test cases for them up-front, to see where things
> are?
>
>
> You mean for the cases that do work as expected? That seems reasonable.
>

All the cases, actually - so we can see what they are, whether they need
improvement, track what those improvements are, etc.


>
> -- adrian
>
>
> (I still find it a bit weird to get const/volatile falling out through
> this process, but yeah, if there's a whole bunch of other cases that fall
> through this way for now, guess it makes  sense)
>
> On Fri, Sep 1, 2017 at 1:24 PM Adrian Prantl via Phabricator <
> reviews at reviews.llvm.org> wrote:
>
>> aprantl added a comment.
>>
>> In https://reviews.llvm.org/D36993#859034, @dblaikie wrote:
>>
>> > In https://reviews.llvm.org/D36993#858768, @JDevlieghere wrote:
>> >
>> > > In https://reviews.llvm.org/D36993#858121, @dblaikie wrote:
>> > >
>> > > > In https://reviews.llvm.org/D36993#858093, @JDevlieghere wrote:
>> > > >
>> > > > > David, apologies for missing your e-mail. I really hate that it
>> doesn't automatically show up in Phabricator! 🙁
>> > > > >
>> > > > > If the tag doesn't have a name attribute, everything will go
>> through this function except: `DW_TAG_pointer_type`,
>> `DW_TAG_ptr_to_member_type`, `DW_TAG_reference_type`,
>> `DW_TAG_rvalue_reference_type`. The first part explains why `class` and
>> `struct` don't show up. I prefer this approach because it's guaranteed to
>> be robust. Every `DW_TAG_*_type` encountered without a name will have
>> something meaningful printed.
>> > > > >
>> > > > > IIRC, the original switch had between 20 and 25 cases.
>> > > >
>> > > >
>> > > > I'm curious what those 20-25 cases were - do you have a
>> copy/roughly describe their contents? Because while 'const' does print
>> nicely, (& volatile would be similar) I'm not sure what the other 10 or so
>> cases might be and whether that's a reasonable way to print them.
>> > >
>> > >
>> > > Here's the list of cases I had originally:
>> > >
>> > >   case DW_TAG_array_type:
>> > >   case DW_TAG_base_type:
>> > >   case DW_TAG_class_type:
>> > >   case DW_TAG_const_type:
>> > >   case DW_TAG_enumeration_type:
>> > >   case DW_TAG_file_type:
>> > >   case DW_TAG_interface_type:
>> > >   case DW_TAG_packed_type:
>> > >   case DW_TAG_pointer_type:
>> > >   case DW_TAG_ptr_to_member_type:
>> > >   case DW_TAG_reference_type:
>> > >   case DW_TAG_restrict_type:
>> > >   case DW_TAG_set_type:
>> > >   case DW_TAG_shared_type:
>> > >   case DW_TAG_string_type
>> > >   case DW_TAG_structure_type:
>> > >   case DW_TAG_subrange_type:
>> > >   case DW_TAG_subroutine_type:
>> > >   case DW_TAG_thrown_type:
>> > >   case DW_TAG_union_type:
>> > >   case DW_TAG_unspecified_type:
>> > >   case DW_TAG_volatile_type:
>> > >
>> >
>> >
>> > Ah, thanks!
>> >
>> > I feel like maybe this should be examined more closely (an example of
>> how each of these would be printed would be ideal, though that might be a
>> bit much) - for example I don't think it makes sense to print out
>> subroutine types like "int subroutine" (rather than "int(float, double)",
>> say) which I /think/ is how they might look based on the current code)
>>
>>
>> Generally agreed, but I think it might make sense to improve this in
>> separate follow-on patches on a case-by-case basis. Getting the
>> pretty-printing entirely right would mean that we would have to implement
>> different pretty-printers for each DW_LANG_foo, since e.g., a C function
>> type would have to be rendered very differently from the same DWARF
>> type-representation in an. e.g., Swift or Fortran context. And even if we
>> choose to always render types as C types it is unclear what to do with
>> types such as DW_TAG_set_type.
>>
>>
>> Repository:
>>   rL LLVM
>>
>> https://reviews.llvm.org/D36993
>>
>>
>>
>>
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