Right now, I am using
TargetMachine::``[addPassesToEmitFile](http://llvm.org/docs/doxygen/html/classllvm_1_1LLVMTargetMachine.html#a356929c1f0d202e4a9d3202aff1dbb05)
to write the output of a backend to a file. How can I tell LLVM to write into a memory buffer instead?