Prepare tests to run on WASIp3 (#1688)

* Prepare tests to run on WASIp3

This commit updates various bits/pieces of infrastructure/tests to
ensure that all tests can run on WASIp3 targets in addition to WASIp2
targets. This isn't yet added to CI because toolchains aren't published
quite just yet, but everything's been tested locally for now. The
changes here are:

* The wit-component/wasm-tools dependencies are updated.
* Task state in Rust bindings is now stored in a TLS variable for wasip3
  instead of a context slot like in wasip2. This is because context
  slots are taken in wasip3 for ABI details (stack pointer and TLS
  base).
* Task state management in TLS on no-std builds requires an auxiliary C
  file to store the actual thread local.
* Tests in C using context slots have a similar change where for wasip2
  they use the context slot but for wasip3 they're now using a TLS variable.
* Tests in Rust using TLS and relying on that being global are updated
  to use `static` variables instead as on wasip3 targets TLS is
  per-task, not global.

* Fix C++ compat in tests

Author: alexcrichton

Cargo.lock

@@ -48,13 +48,13 @@ syn = { version = "2.0.89", features = ["printing"] }
 futures = "0.3.31"
 macro-string = "0.2.0"
 
-wat = "1.254.0"
-wasmparser = "0.254.0"
-wasm-encoder = "0.254.0"
-wasm-metadata = { version = "0.254.0", default-features = false }
-wit-parser = "0.254.0"
-wit-component = "0.254.0"
-wasm-compose = "0.254.0"
+wat = "1.257.0"
+wasmparser = "0.257.0"
+wasm-encoder = "0.257.0"
+wasm-metadata = { version = "0.257.0", default-features = false }
+wit-parser = "0.257.0"
+wit-component = "0.257.0"
+wasm-compose = "0.257.0"
 
 wit-bindgen-core = { path = 'crates/core', version = '0.60.0' }
 wit-bindgen-c = { path = 'crates/c', version = '0.60.0' }

Cargo.toml

@@ -42,6 +42,8 @@ set -ex
 version=$(./ci/print-current-version.sh | sed 's/\./_/g')
 
 realloc=cabi_realloc_wit_bindgen_$version
+wasip3_get=wit_bindgen_${version}_get_task_context
+wasip3_set=wit_bindgen_${version}_set_task_context
 
 rm -f crates/guest-rust/src/rt/wit_bindgen_*.{rs,o,c}
 rm -f crates/guest-rust/src/rt/libwit_bindgen_cabi.a
@@ -60,6 +62,17 @@ pub unsafe extern "C" fn $realloc(
 }
 EOF
 
+cat >./crates/guest-rust/src/rt/async_support/wasip3_context.rs <<-EOF
+// This file is generated by $0
+
+unsafe extern "C" {
+    #[link_name = "$wasip3_get"]
+    pub fn get() -> *mut u8;
+    #[link_name = "$wasip3_set"]
+    pub fn set(ptr: *mut u8);
+}
+EOF
+
 cat >./crates/guest-rust/src/rt/wit_bindgen_cabi_realloc.c <<-EOF
 // This file is generated by $0
 
@@ -86,6 +99,16 @@ void *wasip3_task_set(void *ptr) {
   WASIP3_TASK = ptr;
   return ret;
 }
+
+static _Thread_local void *task_context = NULL;
+
+void *$wasip3_get(void) {
+  return task_context;
+}
+
+void $wasip3_set(void *ptr) {
+  task_context = ptr;
+}
 EOF
 
 build() {