[llvm-commits] [cfe-commits] [Patch] Move TargetData from Target to Support/VMCore

[Jim Grosbach]

Lang,

If I recall correctly, you looked at something similar to this before. Can you elaborate a bit on the obstacles you encountered?

-Jim

On Sep 27, 2012, at 9:42 AM, "Villmow, Micah" <Micah.Villmow at amd.com> wrote:

> 
> 
>> -----Original Message-----
>> From: Hal Finkel [mailto:hfinkel at anl.gov]
>> Sent: Wednesday, September 26, 2012 9:40 PM
>> To: Evan Cheng
>> Cc: Villmow, Micah; llvm-commits at cs.uiuc.edu LLVM; Nadav Rotem; cfe-
>> commits at cs.uiuc.edu cfe; Christopher Lattner
>> Subject: Re: [cfe-commits] [llvm-commits] [Patch] Move TargetData from
>> Target to Support/VMCore
>> 
>> On Wed, 26 Sep 2012 21:18:24 -0700
>> Evan Cheng <evan.cheng at apple.com> wrote:
>> 
>>> 
>>> 
>>> On Sep 26, 2012, at 11:07 AM, Hal Finkel <hfinkel at anl.gov> wrote:
>>> 
>>>> On Tue, 25 Sep 2012 16:16:22 -0700
>>>> Evan Cheng <evan.cheng at apple.com> wrote:
>>>> 
>>>>> Sorry, I understand why you are requesting this but I thinking
>>>>> moving TargetData to support is conceptually dirty.
>>>> 
>>>> Can you please explain this? I think that the opposite is true:
>>>> Having TargetData in Target is conceptually dirty. TargetData
>>>> represents 'target information that is available to frontends and
>>>> IR-level passes without linking to the target descriptions'.
>>> 
>>> Agreed.
>>> 
>>>> As a result, I feel
>>>> that TargetData does not belong with the target-description
>>>> infrastructure, and so it should be moved out of Target so that
>>>> everyone can use it.
>>> 
>>> I agree it should be moved out but at least it's target related.
>>> Polluting Support / VMCore with it is just worse. They have nothing to
>>> do with target data conceptually.
>> 
>> Good point. On the other hand, TargetData is specified along with the
>> core IR language reference. Perhaps the problem really is that auto-
>> upgrade support is in VMCore, and auto-upgrade is full of logic that
>> deals with target-specific intrinsics (and, maybe soon, pointer size
>> information). Maybe making a libTargetData would be better?
> [Villmow, Micah] Targetdata itself is just an in memory representation of
> the target string that is stored in the module. So the information is in
> VMCore, why not the way to access that information?
>> 
>> -Hal
>> 
>>> This is all a matter of taste.
>>> I'll let Chris make the decision.
>>> 
>>> Evan
>>> 
>>>> 
>>>>> Nadav is going to
>>>>> propose a BOF at the DevMeeting to talk about designing an
>>>>> abstraction to expose target information to LLVM ir.
>>>> 
>>>> Great!
>>>> 
>>>> Thanks again,
>>>> Hal
>>>> 
>>>>> Can we hold off
>>>>> this kind of change for now?
>>>>> 
>>>>> Losing the ability to verify isn't a strong enough argument for an
>>>>> immediate change. I don't follow the auto-upgrade argument. Can you
>>>>> elaborate?
>>>>> 
>>>>> Thanks,
>>>>> 
>>>>> Evan
>>>>> 
>>>>> On Sep 21, 2012, at 4:08 PM, "Villmow, Micah"
>>>>> <Micah.Villmow at amd.com> wrote:
>>>>> 
>>>>>> This time with the actual patch
>>>>>> 
>>>>>> From: Villmow, Micah
>>>>>> Sent: Friday, September 21, 2012 4:08 PM
>>>>>> To: llvm-commits at cs.uiuc.edu; cfe-commits at cs.uiuc.edu
>>>>>> Subject: [Patch] Move TargetData from Target to Support/VMCore
>>>>>> 
>>>>>> I have attached a patch which moves TargetData from Target to
>>>>>> Support/VMCore. The reason why I would like to have this change
>>>>>> can be read about in more detail in message [1][2], which in turn
>>>>>> is required for [3]. In short, I need the capability of querying,
>>>>>> if available, target specific information in the bitcode during
>>>>>> verifier and the auto-upgrade mechanism. Because TargetData is in
>>>>>> the target directory, a circular dependency is created when the
>>>>>> verifier and auto-upgrade mechanism utilize the information.
>>>>>> Please let me know what you think and if this approach isn't good,
>>>>>> possible alternate solutions, Micah
>>>>>> 
>>>>>> [1]
>>>>>> http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-September/053277.h
>>>>>> tml
>>>>>> [2]
>>>>>> http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-September/053166.h
>>>>>> tml
>>>>>> [3]
>>>>>> http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-August/052639.html
>>>>>> <move_target_data_to_support_vmcore.txt>__________________________
>>>>>> _____________________ llvm-commits mailing list
>>>>>> llvm-commits at cs.uiuc.edu
>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> --
>>>> Hal Finkel
>>>> Postdoctoral Appointee
>>>> Leadership Computing Facility
>>>> Argonne National Laboratory
>> 
>> 
>> 
>> --
>> Hal Finkel
>> Postdoctoral Appointee
>> Leadership Computing Facility
>> Argonne National Laboratory
> 
> 
> 
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