Clean up runtime exports

[brson]

Right now the interface presented by the runtime is very sloppy. There should basically be three categories of function:

• rust_* - runtime services for use by core/std
• upcall_* - runtime services for use by the compiler
• rust_client_* - runtime services for use by external C libraries (these don't exist yet Create and export rust C API from the runtime #1682)

[graydon]

Agreed. I'd also vaguely like to rename the term upcall to something more obvious.

[brson]

While we're changing upcall let's also put it into the rust_ namespace. What word do you suggest to replace upcall?

[jamorton]

has a word been chosen yet? I could clean this up

[brson]

No, a word has not been chosen. In the interest of making a nice embedding API I think the naming we should use is:

• rust_* - the public embedding API - there are no existing functions in this namespace
• rust_builtin_* - the API used by core - this is the majority of the existing functions
• rust_dbg_* - debug / test APIs
• rust_upcall_* - or whatever the new word for 'upcall' is

@graydon what's the new word for 'upcall'?

[brson]

Though builtin is a pretty long word, maybe there's a shorter synonym

[bblum]

This only affects libs, so is not a backwards-compatibility issue. Renominating for feature-complete.

Most of this will become irrelevant with the new runtime, and the rust runtime's internal interface to C library functions can probably be unstandardized. But we might still want to think about the rust interface to the rest of the stdlib.

[graydon]

just a bug, removing milestone/nomination.

[graydon]

See also #3922

[catamorphism]

Could somebody ( @brson or @bblum ?) summarize what remains to be done here?

[thestinger]

The old runtime support is being removed, so cleaning it up isn't necessary anymore.