* cranelift-wasm: replace `WasmTypesMap` with `ModuleTranslationState`
The `ModuleTranslationState` contains information decoded from the Wasm module
that must be referenced during each Wasm function's translation.
This is only for data that is maintained by `cranelift-wasm` itself, as opposed
to being maintained by the embedder. Data that is maintained by the embedder is
represented with `ModuleEnvironment`.
A `ModuleTranslationState` is returned by `translate_module`, and can then be
used when translating functions from that module.
* cranelift-wasm: rename `TranslationState` to `FuncTranslationState`
To disambiguate a bit with the new `ModuleTranslationState`.
* cranelift-wasm: Reorganize the internal `state` module into submodules
One module for the `ModuleTranslationState` and another for the
`FuncTranslationState`.
* cranelift-wasm: replace `FuncTranslator` with methods on `ModuleTranslationState`
`FuncTranslator` was two methods that always took ownership of `self`, so it
didn't really make sense as an object as opposed to two different functions, or
in this case methods on the object that actually persists for a longer time.
I think this improves ergonomics nicely.
Before:
```rust
let module_translation = translate_module(...)?;
for body in func_bodies {
let mut translator = FuncTranslator::new();
translator.translate(body, ...)?;
}
```
After:
```rust
let module_translation = translate_module(...)?;
for body in func_bodies {
module_translation.translate_func(body, ...)?;
}
```
Note that this commit does not remove `FuncTranslator`. It still exists, but is
just a wrapper over the `ModuleTranslationState` methods, and it is marked
deprecated, so that downstream users get a heads up. This should make the
transition easier.
* Revert "cranelift-wasm: replace `FuncTranslator` with methods on `ModuleTranslationState`"
This reverts commit 075f9ae933bcaae39348b61287c8f78a4009340d.
This commit introduces initial support for multi-value Wasm. Wasm blocks and
calls can now take and return an arbitrary number of values.
The encoding for multi-value blocks means that we need to keep the contents of
the "Types" section around when translating function bodies. To do this, we
introduce a `WasmTypesMap` type that maps the type indices to their parameters
and returns, construct it when parsing the "Types" section, and shepherd it
through a bunch of functions and methods when translating function bodies.
This patch restricts the `Err(..)` return from `blocktype_to_type` to be
`Err(..)` only in the case where it really is an error to continue. The three
use points of `blocktype_to_type` are changed to check for an `Err(..)` rather
than silently ignoring it. There are also cosmetic changes to `type_to_type`
and `tabletype_to_type`.
When compiling wasm_lua_binarytrees, this reduces the number of blocks
allocated by CL by 1.9%. Instruction count falls by 0.1%.
Details:
* `type_to_type` and `tabletype_to_type`:
- Added the function name in the failure message
- No functional change for non-error cases
- Push the `Ok(..)` to expression leaves, where it really applies. This
corrects the misleading impression that, in the case of an unsupported
type, the function returns `Ok` wrapped around whatever
`wasm_unsupported` returns. It doesn't do that, but it certainly reads
like that. This assumes that the LLVM backend will do tail merging, so
the generated code will be unchanged.
* `blocktype_to_type`:
- Change return type from `WasmResult<ir::Type>` to `WasmResult<Option<ir::Type>>`
- Manually inline the call to `type_to_type`, to make this function easier
to read.
- For the non-error case: map `TypeOrFuncType::Type(Type::EmptyBlockType)`
to `Ok(None)` rather than `Err(..)`, since that's what all the call sites
expect - For the error cases, add the function name in the failure
messages
* cranelift-wasm/src/code_translator.rs
- For the three uses of `blocktype_to_type`, use `?` to detect failures and
drop out immediately, meaning that the code will no longer silently ignore
errors.
* [wasm] return a WasmResult from `declare_table_elements`
This method in particular needs to accommodate failure because any table index other than zero is
currently invalid.
* [wasm] additional failure handling improvements
- Adds `WasmResult<()>` as the return type for most of the `ModuleEnvironment` methods that
previously returned nothing.
- Replaces some panics with `WasmError::Unsupported` now that the methods can return a result.
- Adds a `wasm_unsupported!()` macro for early returns with a formatted unsupported message.
