GSoC Project: NCI and Stack Frame Improvements

My Google Summer of Code (2010) objectives are to integrate libffi into the NCI framework and to build a new Stack Frame builder that takes advantage of the llvm.

NCI Framework – The current NCI system has a few limitations which I am going to try to alleviate. I don’t know if I will be able to remove all of the limitations, but I will try to add all of the capabilities of the libffi library to the core of Parrot. This includes being able to define structures as data types for calling functions, adding a few new data types on systems that support them (this would be 64 bit integers on systems that have 64 bit integers, and etc.), as well as adding improvements for calling functions in foreign libraries. The current NCI system in Parrot is not capable of defining a structure for instance, or int64 types. I plan on implementing all of the supported data types in libffi as parts of the modified NCI system. I do plan on retaining the current functionality of the NCI system for people without libffi. I don’t think parrot currently bundles any third party libraries with parrot, but I do know python, for example, bundles libffi with its source code and builds its by default if you don’t make it use your system libffi.

Stack Frame Builder – There are a number of places for integrating the llvm into parrot. One obvious place to start is with the stack frame builder. Translating the stack frame into llvm-ir and running some of the llvm optimization passes over the resulting code could provide parrot with both a JIT system and some speed ups of the generated code. It could also be possible to dump the llvm-ir code to a file, so you end up with a sort of pbc to llvm-ir translation. The resulting llvm-ir can also be compiled into a native binary or dynamic library, which would also be useful because that could cut out some of the overhead for libraries.

The current plans for the stack frame builder are still being mapped out, but for now I am focusing on the NCI system, and I am hoping to have that knocked out relatively quickly so I can move on to the work with the llvm.

John Harrison
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GSoC Student Project, NCI improvements and an llvm based stack frame builder.