[chc4]

Have you read the Copy-and-patch compilation paper? It seems broadly similar to what you're describing, and Deegen. They use GHC's calling convention for it's snippets which has only caller-saved registers and all arguments passed in registers in order to optimize stitching the snippets together (via JIT templating in it, but with tailcalls in your case would probably also be the same design space).

[sillycross]

The copy-and-patch paper is also written by me. Deegen a follow-up work of copy-and-patch, and it will use copy-and-patch as a tool to build its JIT tiers in the future.

[chc4]

Haha, woops! I didn't realize that :)