Add fast path to bypass upcall_require on crate cache hit.

cba0b5e
Opened by Graydon Hoare at 2011-01-27 00:59:14

We always do one upcall_import to access the crate-cache, even though on a cache hit the upcall is not doing anything more complex than a couple indexed-load-and-compare checks and a return.

This is not necessary: we can emit those load/compare checks as a fast(er) hit path that stays in the stub, and only upcall on miss.

Deferring for now because it's still not a big cost at the moment, and there's more work to do around the stubs anyways in terms of refcounting.

  1. WONTFIX (not required for bootstrapping, also obsolete in rustc linkage scheme)

    Graydon Hoare at 2011-01-27 00:59:14