666c2554ea
* Run the GC smoketest with epoch support enabled as well. * Handle safepoints in cold blocks properly. Currently, the way that we find safepoint slots for a given instruction relies on the instruction index order in the safepoint list matching the order of instruction emission. Previous to the introduction of cold-block support, this was trivially satisfied by sorting the safepoint list: we emit instructions 0, 1, 2, 3, 4, ..., and so if we have safepoints at instructions 1 and 4, we will encounter them in that order. However, cold blocks are supported by swizzling the emission order at the last moment (to avoid having to renumber instructions partway through the compilation pipeline), so we actually emit instructions out of index order when cold blocks are present. Reference-type support in Wasm in particular uses cold blocks for slowpaths, and has live refs and safepoints in these slowpaths, so we can reliably "skip" a safepoint (not emit any metadata for it) in the presence of reftype usage. This PR fixes the emission code by building a map from instruction index to safepoint index first, then doing lookups through this map, rather than following along in-order as it emits instructions.
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.