* Cranelift: Introduce the `tail` calling convention
This is an unstable-ABI calling convention that we will eventually use to
support Wasm tail calls.
Co-Authored-By: Jamey Sharp <jsharp@fastly.com>
* Cranelift: Introduce the `return_call` and `return_call_indirect` instructions
These will be used to implement tail calls for Wasm and any other language
targeting CLIF. The `return_call_indirect` instruction differs from the Wasm
instruction of the same name by taking a native address callee rather than a
Wasm function index.
Co-Authored-By: Jamey Sharp <jsharp@fastly.com>
* Cranelift: Implement verification rules for `return_call[_indirect]`
They must:
* have the same return types between the caller and callee,
* have the same calling convention between caller and callee,
* and that calling convention must support tail calls.
Co-Authored-By: Jamey Sharp <jsharp@fastly.com>
* cargo fmt
---------
Co-authored-by: Jamey Sharp <jsharp@fastly.com>
bdfb746548