Reimplement wac-parser on wac-graph.

This commit is a complete reimplementation of `wac-parser`'s resolution to be
based on `wac-graph`.

It also contains an overhaul of the `wac-graph` API to facilitate its use from
`wac-parser`:

* Reimplements `CompositionGraph` on top of `petgraph::StableDiGraph`, which
  eliminates needing to keep track of nodes internally to `CompositionGraph`.
* Packages now populate their type information into the graph's types
  collection rather than having their own collections.
* Splits the `Error` enum into discrete error types for each graph operation;
  this allows the AST resolver to properly attach span information to errors.
* Add type dependency edges for defined types, ensuring topological ordering.
* Fix encoding of defined type aliases so that each encoded alias refers to the
  export index of the previously encoded type.
* Added a debug formatter for `CompositionGraph` that outputs a DOT
  representation (used in resolution tests as well).
* Graph encoding now includes an optional producers custom section.
* Fixed toposort to be in ascending node index order for independent nodes.

The subtype checker implementation was reverted to the previous implementation,
where `invert` and `revert` are called at specific points to change the type of
check being performed; the newer implementation did not give the correct
"expected, found" error messages for AST resolution.

`wac resolve` now outputs a DOT representation of the resolved composition
graph instead of JSON.

Most of the deleted code comes from code that has already moved into
`wac-types` and `wac-graph`.

Closes #79.
Fixes #78.
Fixes #76.

Author: peterhuene

Cargo.lock

@@ -19,6 +19,8 @@ keywords = ["webassembly", "wasm", "components", "component-model"]
 repository = "https://github.com/bytecodealliance/wac"
 
 [dependencies]
+wac-types = { workspace = true }
+wac-graph = { workspace = true }
 wac-resolver = { workspace = true, default-features = false }
 wac-parser = { workspace = true, default-features = false }
 anyhow = { workspace = true }
@@ -30,7 +32,6 @@ owo-colors = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 wat = { workspace = true }
-wasmparser = { workspace = true }
 wasmprinter = { workspace = true }
 thiserror = { workspace = true }
 indexmap = { workspace = true }

Cargo.toml

@@ -21,6 +21,7 @@ semver = { workspace = true }
 serde = { workspace = true, optional = true }
 wasm-encoder = { workspace = true }
 log = { workspace = true }
+wasm-metadata = { workspace = true }
 
 [dev-dependencies]
 pretty_assertions = { workspace = true }

crates/wac-graph/Cargo.toml

@@ -1,5 +1,6 @@
-use crate::{NodeId, PackageId};
+use crate::PackageId;
 use indexmap::IndexMap;
+use petgraph::graph::NodeIndex;
 use std::collections::HashMap;
 use wac_types::{
     CoreExtern, DefinedType, DefinedTypeId, Enum, Flags, FuncResult, FuncTypeId, InterfaceId,
@@ -116,11 +117,11 @@ pub struct State {
     /// The current encoding scope.
     pub current: Scope,
     /// A map of nodes in the graph to their encoded indexes.
-    pub node_indexes: HashMap<NodeId, u32>,
+    pub node_indexes: HashMap<NodeIndex, u32>,
     /// The map of package identifiers to encoded components (either imported or defined).
     pub packages: HashMap<PackageId, u32>,
     /// A map of instantiation nodes to a list of their encoded implicitly imported arguments.
-    pub implicit_args: HashMap<NodeId, Vec<(String, ComponentExportKind, u32)>>,
+    pub implicit_args: HashMap<NodeIndex, Vec<(String, ComponentExportKind, u32)>>,
 }
 
 impl State {