[PATCH] IR: Add specialized debug info metadata nodes
Adrian Prantl
aprantl at apple.com
Mon Feb 9 15:20:42 PST 2015
> On Feb 6, 2015, at 3:37 PM, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>
>
>> On 2015-Feb-04, at 17:17, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>>
>>
>>> On 2015-Feb-04, at 16:44, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>>>
>>>>
>>>> On 2015-Feb-04, at 16:17, Adrian Prantl <aprantl at apple.com> wrote:
>>>>
>>>>
>>>>> On Feb 4, 2015, at 3:53 PM, Frédéric Riss <friss at apple.com> wrote:
>>>>>
>>>>>
>>>>>> On Feb 4, 2015, at 3:46 PM, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>>>>>>
>>>>>>
>>>>>>> On 2015-Feb-04, at 15:37, Frédéric Riss <friss at apple.com> wrote:
>>>>>>>
>>>>>>>>>
>>>>>>>>> - The word 'context' is overloaded: `MDNode::getContext()` already
>>>>>>>>> exists, and returns an `LLVMContext&`; `DIDescriptor` uses 'context'
>>>>>>>>> to mean "the node that this one is defined inside". I chose the
>>>>>>>>> word 'parent' instead of 'context' here. Is this word okay? If
>>>>>>>>> not, what about 'scope'? This will be reflected in the assembly
>>>>>>>>> changes to come (I'd like the C++ names to match the assembly names,
>>>>>>>>> although technically it's not necessary).
>>>>>>>>>
>>>>>>>>> I'd /probably/ go with scope (we already have scope in the MDLocations, so that seems consistent), but fairly on-the-fence.
>>>>>>>>>
>>>>>>>>
>>>>>>>> Weirdly, I didn't even notice that :). In that case I like 'scope'
>>>>>>>> better too. I'll update to that before commit.
>>>>>>>
>>>>>>> Seems most natural. Can the futur getScope() return something that doesn’t derive from MDScope?
>>>>>>
>>>>>> I don't think so.
>>>>>
>>>>> That was my impression also, and it makes it even more appropriate IMHO.
>>>>>
>>>>
>>>> Just a few general remarks to throw into the discussion:
>>>>
>>>> - Would it make sense to use something like tablegen to generate the repetitive parts? I’m slightly worried about copy&paste bugs, moderately worried about refactoring it in the future.
>>>>
>>>
>>> `tablegen` might make sense here, I'm not sure. Frankly, I've never used
>>> it before, and it's not clear to me whether it would actually reduce the
>>> amount of code in this case vs. shifting it over to utils/tablegen (given
>>> the macro usage).
>>>
>>> I think the way the APIs are written, the only real danger is a mismatch
>>> between `MDNodeKeyImpl<>` and the current fields in the class (I believe
>>> other mismatches would be caught by the compiler). As long as the unit
>>> tests are updated along with any refactoring that happens I think the
>>> danger even there is fairly low.
>>>
>>> I'm open to it if there's definite value, though. Maybe as a follow-up?
>>>
>>> @dblaikie: I've seen you poking around tablegen internals a fair bit; any
>>> thoughts on this one?
>>>
>>>> <classllvm_1_1DIScope__inherit__graph.png>
>>>>
>>>> As for scopes, there are several things that bug me about the current class hierarchy that we could fix now:
>>>> - DIFile should not be a scope (the concept of files is IMO orthogonal to scoping and there is always something more appropriate to put a node into: compile unit, module, namespace)
>>>> - DIBasicType should not be scope
>>>> - It’s questionable whether a DICompositetype should be a DIDerivedType
>>>> - A DISubroutineType should be neither a DIDerivedType nor DIScope
>>>> - Using DIDerivedTypes for CV qualifiers is a bit wasteful but it does map nicely to DWARF
>>>>
>>>
>>> Definitely want to get to those :). I think most of those are marked
>>> in the code as `TODO`s (except for the CV-qualifier comment). But I'm
>>> planning to change the schema itself separately from the infrastructure
>>> for it to simplify the triage of any problems that come up (see comments
>>> in PR22264).
>>>
>>>> otherwise, thanks for doing this!
>>>> -- adrian
>>>
>>
>> Here's an updated patch using "scope" instead of "parent" (and updated
>> to match r228242, from David's review of r228212).
>>
>
> *ping*
>
> (While the discussion about the final structure of the class hierarchy
> and scopes/types/etc. is a good one, it's somewhat independent of the
> patch in question.)
>
> This is a fast ping, but I'm just about blocked on this, and with all the
> discussion about the future I'm afraid everyone forgot to sign off on
> this step forward.
>
>
> <0001-IR-Add-specialized-debug-info-metadata-nodes.patch>
This is fine as far as I am concerned.
-- adrian
More information about the llvm-commits
mailing list