[llvm-dev] [LLVM][DISubprogram][LL format updation query] Question regarding moving DISubprogram DIFlags to DISPFlag.

Chirag Patel via llvm-dev
Thu, 20 Feb 2020 08:57:23 -0000

Yes, removing the support for isLocal, isDefinition fields completely from ll
files, currently the LLParser still parses it. I want to remove it and update
the all the ll files which still uses it.
Also the metadata read will support old format, no changes in that.

so if ll file has isLocal and isDefinition it will result in parser error. But
the bitcode read will work as usual.

- Chirag.

-----Original Message-----
From: Djordje Todorovic <djordje.todorovic at rt-rk.com>
Sent: 20 February 2020 14:16
To: Chirag Patel <Chirag at raincode.com>; llvm-dev at lists.llvm.org
Subject: Re: [llvm-dev] [LLVM][DISubprogram][LL format updation query] Question
regarding moving DISubprogram DIFlags to DISPFlag.

Hi Chirag,

On 20.2.20. 07:51, Chirag Patel via llvm-dev wrote:
> Hello,
>
>
>
> In regard to the review request https://reviews.llvm.org/D74470,
>
> I am trying to move five of the DIFlags to DISPFlag for the moment namely
DIFlagExplicit, DIFlagPrototyped, DIFlagNoReturn, DIFlagThunk,
DIFlagAllCallsDescribed.
>
> The llvm ir format for DISubprogram currently has backword compatibility
where the isLocal, isDefinition, virtuality, isOptimized and SPFlags are
mutually exclusive.
>
> My question is,
>
> is it a good idea to remove the booleans support'(isLocal,
isDefinition) and move most of it to spflags and flags in llvm ir?

But it was already "done", we currently have the
'DISPFlagLocalToUnit' and 'DISPFlagDefinition' (please take a
look into the https://reviews.llvm.org/D54755 and
https://reviews.llvm.org/D59288).

The llvm ir backward compatibility does not list the clear requirements on
documentations page. This change affects more then 750 ll
files.
>

I am not sure what change will take 750 ll files? Removing the 'isLocal'
and 'isDefinition'? I think the role of LLVM IR backward compatibility
is to support interpretation of the old metadata in terms of the newest one.
Therefore, if there is an 'isDefinition' metadata field, that should be
interpreted as 'DISPFlagDefinition'.