Panama Updates

[Tobi Ajila]

Last time we spoke we talked about clarifying some of the basic layout
concepts. If I recall correctly there was general consensus on the concepts
but the terminology differed. Here is what I have from our previous
discussions:

Layout - Describes how the data is organized.

LayoutType - Combines a Layout and Java carrier type information and
facilitates the translation between the two.

MemoryRegion - Describes where the data is located. A contiguous range of
memory located on/off-heap, RDMA, etc.

Scope - Memory allocator. Manages the life time of allocated memory,
responsible for freeing memory.

Native Type - Types used by the native language

Carrier Type - Java representation of the native type

Pointer & Reference - Combines a MemoryRegion and LayoutType. My
understanding is that Pointer simply points at the data (you must
dereference it to touch the fields) whereas Reference lets you grab the
fields

Does that look right to you?

Where would 'Layout Descriptor' fit in the list above? Also, you mentioned
concepts like Type and TypeDescriptor, are those just synonyms for Layout
and LayoutDescriptor?

We should begin to sketch out a spec describing the core concepts
(previously mentioned concepts as well as things like bit-fields, alignment
and atomicity) based on what we know so far. At the very least this would
help iron out the terminology and expose areas that require further work.

Along the same lines, it would be good to formalize a list of objectives
for the first release of Panama. i.e. Support C function calling, on/off
heap data access, etc.

What do you think about these propositions?

On our end we've been experimenting with the OpenJDK Panama builds. At this
point we have native C function calling working with primitives as well as
struct types. Minimal changes required to get this up and running.

I've taken a look and John's C++ observations but I don't have much to
contribute on that topic right now as we have not spent much time
investigating it. I hope to have some feedback as we start doing some C++
prototyping.

Hope to hear your updates.

Regards,
--Tobi