[llvm-dev] LLVM bc converter from LLVM 3.9 to LLVM 3.1

Hongbin Zheng via llvm-dev llvm-dev at lists.llvm.org
Tue Aug 2 16:53:30 PDT 2016

Thanks Jakub. Looks Like I didn't rely all.

I also have a look at the code, looks like it directly parse the bitcode
and build in memory representation in a different LLVM version than the
bitcode. Is this correct?

According to your description, I guess the BitCodeWriter should be the one
to do the bitcode version downgrade, right?

Does this took work on LLVM 3.9svn?

And could you give some hints about how you test the bitcode translator?


On Tue, Aug 2, 2016 at 3:25 PM, Jakub Kuderski <kubakuderski+llvm at gmail.com>

> I'm not sure if it was intended, but I think that you responded only to me
> (not to the list).
> Anyway, RenderScript currently uses llvm 3.2 IR as binary
> representation/exchangeable format, but the llvm version is higher
> internally. Essentially, there it reads old bitcode and operates on the
> newer one in memory. When it's done, it's also able to output bitcode in
> the old format. The corresponding classes should be something like
> BitCodeReader and BitCodeWriter.
> The reader/writer is maintained to work with Android's llvm version, which
> follows upstream llvm version.
> I haven't worked on it myself, but if you have some specific questions, I
> should be able to point you to appropriate people.
> Regards
> On 2 August 2016 at 15:17, Hongbin Zheng <etherzhhb at gmail.com> wrote:
>> Hi Jakub,
>> Thanks a lot. Do you have any document about this tool? or could you gave
>> me a rough idea what it do?
>> Thanks
>> Hongbin
>> On Tue, Aug 2, 2016 at 3:06 PM, Jakub Kuderski <
>> kubakuderski+llvm at gmail.com> wrote:
>>> Hi Hongbin,
>>> Android's RenderScript uses a tool like that. You can find the sources
>>> here:
>>> https://android.googlesource.com/platform/frameworks/compile/libbcc/+/master/bcinfo/
>>>  .
>>> Best,
>>> Jakub
>>> On 2 August 2016 at 11:10, Hongbin Zheng via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>> Hi mailing list,
>>>> I has been working on a large project that is based on LLVM 3.1.
>>>> Recently we are thinking to introduce an LLVM bc converter from LLVM 3.9 to
>>>> LLVM 3.1, such that we can introduce some of the newest LLVM analyses and
>>>> optimizations to our  LLVM 3.1 based project.
>>>> Have you worked on similar things that converting LLVM bc downward and
>>>> has anything to share?
>>>> Thanks
>>>> Hongbin
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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