RD-10562 Implement OSR for iterators

[alexzerntev]

• Updated aggregations to use OSR
• Updated lists to use OSR
• Updated joins to use OSR
• Updated iterables to use OSR
• Updated Json list reader to use OSR
• RecordObject now extends Dynamic Truffle object

[bgaidioz]

A question about the design. It felt to me like the implementation doesn't use the RepeatingNode correctly. But I only found a specific example to compare this to.

[bgaidioz]

The doc of executeRepeatingWithValue says: "return a value v satisfying shouldContinue(v) == true if the method should be executed again to complete the loop and any other value if it must not." (That last part I interpret as "any other value that doesn' t satisfy shouldContinue.)

I see shouldContinue's code is comparing its parameter to initialLoopStatus, which is a status, an object like CONTINUE_LOOP_STATUS. But with executeRepeatingWithValue returning the result array, it will perform the same test with that array. I understand that will evaluate to false and only the check on currentIdx is going to matter. But that feels like not the intention, to spend the whole loop execution comparing the array to the "enum".

I interpret the OptimizedOSRLoopNode logic as if the return value of the node is a status value (and can be custom if using the withValue version: BREAK, TOOK_TOO_LONG, INTERRUPTED, etc.) and the way a loop would return an actual result would be either as a side-effect (by updating a mutable object passed as a parameter) or by exposing a getResult() method that returns an object it would have allocated internally. e.g. all these OSR...Node classes would compute the result internally, and inherit an abstract class (which itself inherits RepeatingNode), that would require a getResult() method. Which is called after execute?

Node existNode = new ExistNode();
existNode.execute(); // returns the status, in our case `true/false`, no need for a custom status?
return existNode.getResult();

I looked in TruffleScheme code a bit everywhere to find how loop-nodes that return a value are implemented. Scheme has plenty, like length, map, etc. All the expected ones in fact work with regular for loops instead of using RepeatingNode (they probably didn't fix them yet..?). There's one place I found the TailRecursiveLoop (which is a RepeatingNode) called, and it goes with calling execute (ignoring its result) and picking the result from elsewhere. In that specific case, the node returning a value through execute (TailRecursiveRootNode) is initialized with an index where to write the result too, and the looping node (TailRecursiveLoopNode) is getting it as a parameter. Internally, it writes in that index, while looping with a regular status implementation. Which is quite like it would be initialized with a mutable object and update it as the loop runs.

[alexzerntev]

todo, remove the if

[alexzerntev]

To be closed, will be merged through #379