Is an ExitBlock a BasicBlock?

[cqc-alec]

In the current implementation, there are two kinds of BasicBlock: Block and Exit. In the spec, BasicBlock and ExitBlock are distinguished:

All children except the second are BasicBlock-nodes, the first is the entry block. The second child is an ExitBlock node

Which is the more natural approach?

[ss2165]

I think this is a misaligned usage of "BasicBlock" in the spec and the implementation.
Essentially BasicBlock(Spec) = BasicBlock::Block(Implementation).

I think the implementation one is nicer. But "Block::Block" isn't very nice.
How about converging on "Basic::{Block, Exit}" ?
I.e. Block and Exit are both Basic, CFG nodes have only Basic children. The second child must be Exit, all others are Block.

[cqc-alec]

Sounds good to me; I guess you mean "CFG nodes can have only Basic children".

[ss2165]

yes, edited

[cqc-alec]

Was about to convert this to an Issue, but then thought, feels a bit of a cop-out; "Basic" is an adjective and it would be better to have a noun for the node type. But it's hard to think of one that covers both "basic block" and "exit node".

We could stick with what we have in the implementation but rename the "Block" subtype to "Process": so "BasicBlock::{Process, Exit}"?

[ss2165]

What about BasicBlock::DFB for "Dataflow Block"

[cqc-alec]

That works.

[cqc-alec]

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