[LLVMdev] creating new Metadata

[Oksana Tkachuk]

Hello,
we figured out our problem: we were not grabbing the right context.
Here is a snippet of code that works for us, in case somebody would like to
know:

  //iterate over instructions

  ConstantInt *CI = ConstantInt::get(getGlobalContext(), APInt(8, n));
  SmallVector<Value*, 1> V;
  V.push_back(CI);
  MDNode *Node = MDNode::get(Ins->getContext(), V.data(), V.size());

  Inst->setMetadata("mydata", Node);

Cheers,
Oksana

On Thu, Dec 22, 2011 at 8:14 AM, John Criswell <criswell at illinois.edu>wrote:

>  On 12/21/11 11:24 PM, Oksana Tkachuk wrote:
>
> Hello,
> Thank you very much for the pointers.
> I am are able to create new MDNodes, filled with some constants, and
> attach them
> to llvm instructions. However, the metadata map is not getting updated as
> expected.
> For example, instead of the expected new entry
>
>
> If you look at PoolMDPass::runOnModule(), you'll see that the MDNodes are
> stored in a container (ValueToPoolNodes) and that they are added as
> operands to a NamedMDNode.  I think you have to make your MDNodes operands
> of a NamedMDNode in order to get them to work properly.
>
> -- John T.
>
>
> !n = metadata !{some values}
>
> we are getting
>
> !n = metadata !{null}
>
> Do you know what might be wrong? Do we need to enter the MDNodes into the
> map explicitly?
>
> Thank you,
> Oksana
>
>
> On Tue, Dec 20, 2011 at 7:25 PM, 陳韋任 <chenwj at iis.sinica.edu.tw> wrote:
>
>>  > Dear llvm-ers,
>> > I am trying to attach a customized metadata to llvm instructions.
>> > Let's say, I want to attach some number to each instruction.
>> > I am trying to use
>> >
>> > void Instruction::setMetadata(unsigned KindID, MDNode* Node)
>> >
>> > but I am not sure how to create a brand new instance of an MDNode.
>> > Do you have any code samples demonstrating how to do that?
>> >
>> > Due to some tool dependencies, I am using LLVM 2.7
>>
>>   `grep -r MDNode` in $LLVM_SOURCE may give you some examples.  I don't
>> know if
>> there is a doxygen for LLVM 2.7, but you can see include/llvm/Metadata.h
>> and
>> unittests/VMCore/MetadataTest.cpp to know how to create a MDNode. Below
>> is code
>> snipt taken form MetadataTest.cpp.
>>
>> ---
>>  MDString *s1 = MDString::get(Context, StringRef(&x[0], 3));
>>  MDString *s2 = MDString::get(Context, StringRef(&y[0], 3));
>>  ConstantInt *CI = ConstantInt::get(getGlobalContext(), APInt(8, 0));
>>
>>  std::vector<Value *> V;
>>  V.push_back(s1);
>>  V.push_back(CI);
>>  V.push_back(s2);
>>
>>  MDNode *n1 = MDNode::get(Context, &V[0], 3);
>> ---
>>
>> HTH,
>> chenwj
>>
>> --
>> Wei-Ren Chen (陳韋任)
>> Computer Systems Lab, Institute of Information Science,
>> Academia Sinica, Taiwan (R.O.C.)
>> Tel:886-2-2788-3799 #1667
>> Homepage: http://people.cs.nctu.edu.tw/~chenwj
>>
>
>
>
> _______________________________________________
> LLVM Developers mailing listLLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.eduhttp://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20111223/c683df33/attachment.html>