Refactor baseline and optimized runtimes (bytecodealliance#168)

This patch modularises the optimized runtime in the same manner as the
baseline runtime already was. It factors out the `StackChain` logic into
a separate module `stack_chain`, which is needed to add support for
backtraces to the baseline implementation (yet to be done!).

Author: dhil

.github/workflows/main.yml

@@ -647,7 +647,7 @@ jobs:
 
     # Test baseline implementation
     - name: Baseline implementation
-      run: cargo test --features=default,typed_continuations_baseline_implementation
+      run: cargo test --features=default,wasmfx_baseline
       env:
         RUST_BACKTRACE: 1
 

Cargo.toml

@@ -410,9 +410,9 @@ unsafe_disable_continuation_linearity_check = [
 ]
 
 # The following toggles the baseline implementation of typed continuations.
-typed_continuations_baseline_implementation = [
-  "wasmtime-cranelift/typed_continuations_baseline_implementation",
-  "wasmtime/typed_continuations_baseline_implementation"
+wasmfx_baseline = [
+  "wasmtime-cranelift/wasmfx_baseline",
+  "wasmtime/wasmfx_baseline"
 ]
 
 # CLI subcommands for the `wasmtime` executable. See `wasmtime $cmd --help`

crates/cranelift/Cargo.toml

@@ -39,6 +39,6 @@ component-model = ["wasmtime-environ/component-model"]
 incremental-cache = ["cranelift-codegen/incremental-cache"]
 wmemcheck = []
 unsafe_disable_continuation_linearity_check = []
-typed_continuations_baseline_implementation = []
+wasmfx_baseline = []
 gc = ["wasmtime-environ/gc"]
 threads = ["wasmtime-environ/threads"]

crates/cranelift/src/func_environ.rs

@@ -24,7 +24,7 @@ use wasmtime_environ::{
 use wasmtime_environ::{FUNCREF_INIT_BIT, FUNCREF_MASK};
 
 cfg_if::cfg_if! {
-    if #[cfg(feature = "typed_continuations_baseline_implementation")] {
+    if #[cfg(feature = "wasmfx_baseline")] {
         use crate::wasmfx::baseline as wasmfx_impl;
     } else {
         use crate::wasmfx::optimized as wasmfx_impl;

crates/cranelift/src/wasmfx/mod.rs

@@ -7,14 +7,8 @@
 /// implementations.
 mod shared;
 
-#[cfg_attr(
-    not(feature = "typed_continuations_baseline_implementation"),
-    allow(dead_code)
-)]
+#[cfg_attr(not(feature = "wasmfx_baseline"), allow(dead_code))]
 pub(crate) mod baseline;
 
-#[cfg_attr(
-    feature = "typed_continuations_baseline_implementation",
-    allow(dead_code)
-)]
+#[cfg_attr(feature = "wasmfx_baseline", allow(dead_code))]
 pub(crate) mod optimized;

crates/wasmtime/Cargo.toml

@@ -270,4 +270,4 @@ std = [
 unsafe_disable_continuation_linearity_check = []
 
 # Toggle the baseline implementation of WasmFX
-typed_continuations_baseline_implementation = ["async"]
+wasmfx_baseline = ["async"]

crates/wasmtime/src/runtime/store.rs

@@ -80,7 +80,7 @@ use crate::instance::InstanceData;
 use crate::linker::Definition;
 use crate::module::{BareModuleInfo, RegisteredModuleId};
 use crate::prelude::*;
-use crate::runtime::vm::continuation::{StackChain, StackChainCell, StackLimits};
+use crate::runtime::vm::continuation::stack_chain::{StackChain, StackChainCell, StackLimits};
 use crate::runtime::vm::mpk::{self, ProtectionKey, ProtectionMask};
 use crate::runtime::vm::{
     Backtrace, ExportGlobal, GcHeapAllocationIndex, GcRootsList, GcStore,

crates/wasmtime/src/runtime/vm.rs

@@ -5,7 +5,7 @@
 
 use alloc::sync::Arc;
 use anyhow::{Error, Result};
-use continuation::StackChainCell;
+use continuation::stack_chain::StackChainCell;
 use core::fmt;
 use core::ptr::NonNull;
 use core::sync::atomic::{AtomicU64, AtomicUsize, Ordering};