Hi Chris,> Devang and I wrote up a description of this new LLVM 2.7 feature here: > http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.htmlThat's useful but it would be great if you could include programming idioms/examples showing to attach metadata and how to query it later. For example, it wasn't obvious to me that you can't attach an MDString to an instruction but should wrap it in an MDNode first... Cheers, Anton.