[fpc-devel] Autogenerated names for internal RecordDefs

[Sven Barth]

Am 01.12.2019 um 11:02 schrieb Blaise at blaise.ru:
> On 30.11.2019 20:47, Sven Barth via fpc-devel wrote:
>> Am 30.11.2019 um 13:27 schrieb Blaise at blaise.ru:
>>> { This is a resubmission of 
>>> https://lists.freepascal.org/pipermail/fpc-devel/2019-August/041915.html 
>>> }
>>> trecorddef.create_global_internal generates internal RecordDef names as
>>>     '$InternalRec'+tostr(current_module.deflist.count)
>>> However, since such internal RecordDefs are not necessarily 
>>> registered afterwards (i.e. deflist.count is not going to be 
>>> bumped), such names do not contain actual DefIDs, and thus are not 
>>> unique within a module.
>>> 1) So, what is the point of that misleading numerical suffix? I 
>>> propose that it be dropped.
>>> 2) My understanding is that a name should never be autogenerated for 
>>> an internal RecordDef that is going to be registered with a DefID. I 
>>> propose that this be asserted (two variants are offered).
>>
>> I've fixed this now in r43616 by using the correct way to generate a 
>> unique ID string.
>
> You are invoking unique_id_str before the inherited constructor sets 
> defid:=defid_not_registered. Before that, defid is 0, so the 
> aforementioned test case shows:
>> TRUE    $vmtdef$C
>> FALSE   $rttidef$INIT_$U_$$_C
>> FALSE   $InternalRec00000000
>> FALSE   $InternalRec00000000
>> FALSE   $rttidef$RTTI_$U_$$_C
>> FALSE   $InternalRec00000000
>> FALSE   $InternalRec00000000
>> FALSE   $InternalRec00000000
>> FALSE   $InternalRec00000000
>> FALSE   $InternalRec00000000
> At the very least:
>     defid:=defid_not_registered;
>     name:='$InternalRec'+unique_id_str;
> which I find hacky.
>
>  The LLVM backend makes use of anonymous record defs and I don't know 
> whether your patch would break that.
>
> Presumably, if such duplicate internal names were breaking LLVM, it 
> would have been noticed already?
> Maybe Jonas could weigh in?
>

Fixed in r43624 and r43625. I've decided to keep the unique names, 
because they are useful when debugging. More useful then say the Self value.

Regards,
Sven