Commit Graph

3 Commits

Author SHA1 Message Date
Alex Crichton
29c7de7340 Update wasm-tools dependencies (#4970)
* Update wasm-tools dependencies

This update brings in a number of features such as:

* The component model binary format and AST has been slightly adjusted
  in a few locations. Names are dropped from parameters/results now in
  the internal representation since they were not used anyway. At this
  time the ability to bind a multi-return function has not been exposed.

* The `wasmparser` validator pass will now share allocations with prior
  functions, providing what's probably a very minor speedup for Wasmtime
  itself.

* The text format for many component-related tests now requires named
  parameters.

* Some new relaxed-simd instructions are updated to be ignored.

I hope to have a follow-up to expose the multi-return ability to the
embedding API of components.

* Update audit information for new crates
2022-09-27 13:12:34 -05:00
Alex Crichton
57dca934ad Upgrade wasm-tools crates, namely the component model (#4715)
* Upgrade wasm-tools crates, namely the component model

This commit pulls in the latest versions of all of the `wasm-tools`
family of crates. There were two major changes that happened in
`wasm-tools` in the meantime:

* bytecodealliance/wasm-tools#697 - this commit introduced a new API for
  more efficiently reading binary operators from a wasm binary. The old
  `Operator`-based reading was left in place, however, and continues to
  be what Wasmtime uses. I hope to update Wasmtime in a future PR to use
  this new API, but for now the biggest change is...

* bytecodealliance/wasm-tools#703 - this commit was a major update to
  the component model AST. This commit almost entirely deals with the
  fallout of this change.

The changes made to the component model were:

1. The `unit` type no longer exists. This was generally a simple change
   where the `Unit` case in a few different locations were all removed.
2. The `expected` type was renamed to `result`. This similarly was
   relatively lightweight and mostly just a renaming on the surface. I
   took this opportunity to rename `val::Result` to `val::ResultVal` and
   `types::Result` to `types::ResultType` to avoid clashing with the
   standard library types. The `Option`-based types were handled with
   this as well.
3. The payload type of `variant` and `result` types are now optional.
   This affected many locations that calculate flat type
   representations, ABI information, etc. The `#[derive(ComponentType)]`
   macro now specifically handles Rust-defined `enum` types which have
   no payload to the equivalent in the component model.
4. Functions can now return multiple parameters. This changed the
   signature of invoking component functions because the return value is
   now bound by `ComponentNamedList` (renamed from `ComponentParams`).
   This had a large effect in the tests, fuzz test case generation, etc.
5. Function types with 2-or-more parameters/results must uniquely name
   all parameters/results. This mostly affected the text format used
   throughout the tests.

I haven't added specifically new tests for multi-return but I changed a
number of tests to use it. Additionally I've updated the fuzzers to all
exercise multi-return as well so I think we should get some good
coverage with that.

* Update version numbers

* Use crates.io
2022-08-17 16:17:34 +00:00
Alex Crichton
651f40855f Add support for nested components (#4285)
* Add support for nested components

This commit is an implementation of a number of features of the
component model including:

* Defining nested components
* Outer aliases to components and modules
* Instantiating nested components

The implementation here is intended to be a foundational pillar of
Wasmtime's component model support since recursion and nested components
are the bread-and-butter of the component model. At a high level the
intention for the component model implementation in Wasmtime has long
been that the recursive nature of components is "erased" at compile time
to something that's more optimized and efficient to process. This commit
ended up exemplifying this quite well where the vast majority of the
internal changes here are in the "compilation" phase of a component
rather than the runtime instantiation phase. The support in the
`wasmtime` crate, the runtime instantiation support, only had minor
updates here while the internals of translation have seen heavy updates.

The `translate` module was greatly refactored here in this commit.
Previously it would, as a component is parsed, create a final
`Component` to hand off to trampoline compilation and get persisted at
runtime. Instead now it's a thin layer over `wasmparser` which simply
records a list of `LocalInitializer` entries for how to instantiate the
component and its index spaces are built. This internal representation
of the instantiation of a component is pretty close to the binary format
intentionally.

Instead of performing dataflow legwork the `translate` phase of a
component is now responsible for two primary tasks:

1. All components and modules are discovered within a component. They're
   assigned `Static{Component,Module}Index` depending on where they're
   found and a `{Module,}Translation` is prepared for each one. This
   "flattens" the recursive structure of the binary into an indexed list
   processable later.

2. The lexical scope of components is managed here to implement outer
   module and component aliases. This is a significant design
   implementation because when closing over an outer component or module
   that item may actually be imported or something like the result of a
   previous instantiation. This means that the capture of
   modules and components is both a lexical concern as well as a runtime
   concern. The handling of the "runtime" bits are handled in the next
   phase of compilation.

The next and currently final phase of compilation is a new pass where
much of the historical code in `translate.rs` has been moved to (but
heavily refactored). The goal of compilation is to produce one "flat"
list of initializers for a component (as happens prior to this PR) and
to achieve this an "inliner" phase runs which runs through the
instantiation process at compile time to produce a list of initializers.
This `inline` module is the main addition as part of this PR and is now
the workhorse for dataflow analysis and tracking what's actually
referring to what.

During the `inline` phase the local initializers recorded in the
`translate` phase are processed, in sequence, to instantiate a
component. Definitions of items are tracked to correspond to their root
definition which allows seeing across instantiation argument boundaries
and such. Handling "upvars" for component outer aliases is handled in
the `inline` phase as well by creating state for a component whenever a
component is defined as was recorded during the `translate` phase.
Finally this phase is chiefly responsible for doing all string-based
name resolution at compile time that it can. This means that at runtime
no string maps will need to be consulted for item exports and such.
The final result of inlining is a list of "global initializers" which is
a flat list processed during instantiation time. These are almost
identical to the initializers that were processed prior to this PR.

There are certainly still more gaps of the component model to implement
but this should be a major leg up in terms of functionality that
Wasmtime implements. This commit, however leaves behind a "hole" which
is not intended to be filled in at this time, namely importing and
exporting components at the "root" level from and to the host. This is
tracked and explained in more detail as part of #4283.

cc #4185 as this completes a number of items there

* Tweak code to work on stable without warning

* Review comments
2022-06-21 13:48:56 -05:00