* Introduce a `TargetFrontendConfig` type.
`TargetFrontendConfig` is information specific to the target which is
provided to frontends to allow them to produce Cranelift IR for the
target. Currently this includes the pointer size and the default calling
convention.
The default calling convention is now inferred from the target, rather
than being a setting. cranelift-native is now just a provider of target
information, rather than also being a provider of settings, which gives
it a clearer role.
And instead of having cranelift-frontend routines require the whole
`TargetIsa`, just require the `TargetFrontendConfig`, and add a way to
get the `TargetFrontendConfig` from a `Module`.
Fixes#529.
Fixes#555.
* Move `return_at_end` out of Settings and into the wasm FuncEnvironment.
The `return_at_end` flag supports users that want to append a custom
epilogue to Cranelift-produced functions. It arranges for functions to
always return via a single return statement at the end, and users are
expected to remove this return to append their code.
This patch makes two changes:
- First, introduce a `fallthrough_return` instruction and use that
instead of adding a `return` at the end. That's simpler than having
users remove the `return` themselves.
- Second, move this setting out of the Settings and into the wasm
FuncEnvironment. This flag isn't something the code generator uses,
it's something that the wasm translator uses. The code generator
needs to preserve the property, however we can give the
`fallthrough_return` instruction properties to ensure this as needed,
such as marking it non-cloneable.
* Add 'jump_table_entry' and 'indirect_jump' instructions.
* Update CodeSink to keep track of code size. Pretty up clif-util's disassembly output.
* Only disassemble the machine portion of output. Pretty print the read-only data after it.
* Update switch frontend code to use new br_table instruction w/ default.
