llvm dev - Oct 2016 - RFC: Removing the DataStreamer and MemoryObject interfaces

Hi all,

BitstreamReader is the only in-tree client of the DataStreamer and
MemoryObject interfaces. In practice when using user-facing LLVM tools, the
bitcode will normally either be in memory or in a file, so the best way to
access it is through memory, either directly or memory mapped.

As part of some refactorings I am making to BitstreamReader, I would like
to simplify it by changing it to use a memory buffer directly and then
removing the DataStreamer and MemoryObject interfaces.

My understanding that the only significant user of that interface as
designed (for network streaming) is PNaCl, however it looks like removing
this interface would not impose a significant burden on that project; they
are already maintaining a couple of forks of BitstreamReader [1] so it
would appear that the only change necessary on their side would be to also
fork the interfaces.

If you are aware of any other significant users, please speak up!

Thanks,
-- 
-- 
Peter

[1] https://chromium.googlesource.com/native_client/pnacl-llvm/+/master/
include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
https://chromium.googlesource.com/native_client/pnacl-subzero/+/master/pnacl-llvm/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
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And on a separate thread [0] Derek indicated he'd be fine with removing it.
I'll leave this thread open until end of Monday to receive any other
opinions, then proceed to remove it.

Peter

[0]
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161024/400754.html

On Fri, Oct 28, 2016 at 10:08 AM, Peter Collingbourne <peter at pcc.me.uk>
wrote:
> Hi all,
>
> BitstreamReader is the only in-tree client of the DataStreamer and
> MemoryObject interfaces. In practice when using user-facing LLVM tools, the
> bitcode will normally either be in memory or in a file, so the best way to
> access it is through memory, either directly or memory mapped.
>
> As part of some refactorings I am making to BitstreamReader, I would like
> to simplify it by changing it to use a memory buffer directly and then
> removing the DataStreamer and MemoryObject interfaces.
>
> My understanding that the only significant user of that interface as
> designed (for network streaming) is PNaCl, however it looks like removing
> this interface would not impose a significant burden on that project; they
> are already maintaining a couple of forks of BitstreamReader [1] so it
> would appear that the only change necessary on their side would be to also
> fork the interfaces.
>
> If you are aware of any other significant users, please speak up!
>
> Thanks,
> --
> --
> Peter
>
> [1] https://chromium.googlesource.com/native_client/pnacl-
> llvm/+/master/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
> https://chromium.googlesource.com/native_client/pnacl-subzero/+/master/
> pnacl-llvm/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
>


-- 
-- 
Peter
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Awesome!

Thanks,
Rafael


On 28 October 2016 at 13:14, Peter Collingbourne <peter at pcc.me.uk>
wrote:
> And on a separate thread [0] Derek indicated he'd be fine with removing
it.
> I'll leave this thread open until end of Monday to receive any other
> opinions, then proceed to remove it.
>
> Peter
>
> [0]
>
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161024/400754.html
>
> On Fri, Oct 28, 2016 at 10:08 AM, Peter Collingbourne <peter at
pcc.me.uk>
> wrote:
>>
>> Hi all,
>>
>> BitstreamReader is the only in-tree client of the DataStreamer and
>> MemoryObject interfaces. In practice when using user-facing LLVM tools,
the
>> bitcode will normally either be in memory or in a file, so the best way
to
>> access it is through memory, either directly or memory mapped.
>>
>> As part of some refactorings I am making to BitstreamReader, I would
like
>> to simplify it by changing it to use a memory buffer directly and then
>> removing the DataStreamer and MemoryObject interfaces.
>>
>> My understanding that the only significant user of that interface as
>> designed (for network streaming) is PNaCl, however it looks like
removing
>> this interface would not impose a significant burden on that project;
they
>> are already maintaining a couple of forks of BitstreamReader [1] so it
would
>> appear that the only change necessary on their side would be to also
fork
>> the interfaces.
>>
>> If you are aware of any other significant users, please speak up!
>>
>> Thanks,
>> --
>> --
>> Peter
>>
>> [1]
>>
https://chromium.googlesource.com/native_client/pnacl-llvm/+/master/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
>>
https://chromium.googlesource.com/native_client/pnacl-subzero/+/master/pnacl-llvm/include/llvm/Bitcode/NaCl/NaClBitstreamReader.h
>
>
>
>
> --
> --
> Peter