Change manual dependency on wasm-gc executable to an automatic cargo dependency. (#3854)

Improves user experience.

substrate/core/utils/wasm-builder/src/lib.rs

@@ -75,7 +75,6 @@
 //! WASM builder requires the following prerequisities for building the WASM binary:
 //!
 //! - rust nightly + `wasm32-unknown-unknown` toolchain
-//! - wasm-gc
 //!
 
 use std::{env, fs, path::PathBuf, process::{Command, Stdio, self}};

substrate/core/utils/wasm-builder/src/prerequisites.rs

@@ -14,9 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::{process::{Command, Stdio}, fs};
-
-use std::env;
+use std::{env, fs};
 use tempfile::tempdir;
 
 /// Checks that all prerequisites are installed.
@@ -28,15 +26,6 @@ pub fn check() -> Option<&'static str> {
 		return Some("Rust nightly not installed, please install it!")
 	}
 
-	if Command::new("wasm-gc")
-		.stdout(Stdio::null())
-		.stderr(Stdio::null())
-		.status()
-		.map(|s| !s.success()).unwrap_or(true)
-	{
-		return Some("`wasm-gc` not installed, please install it!")
-	}
-
 	check_wasm_toolchain_installed()
 }
 

substrate/core/utils/wasm-builder/src/wasm_project.rs

@@ -16,7 +16,7 @@
 
 use crate::write_file_if_changed;
 
-use std::{fs, path::{Path, PathBuf}, borrow::ToOwned, process::{Command, self}, env};
+use std::{fs, path::{Path, PathBuf}, borrow::ToOwned, process, env};
 
 use toml::value::Table;
 
@@ -352,15 +352,8 @@ fn compact_wasm_file(
 		.join(format!("{}.wasm", wasm_binary));
 	let wasm_compact_file = project.join(format!("{}.compact.wasm", wasm_binary));
 
-	let res = Command::new("wasm-gc")
-		.arg(&wasm_file)
-		.arg(&wasm_compact_file)
-		.status()
-		.map(|s| s.success());
-
-	if !res.unwrap_or(false) {
-		panic!("Failed to compact generated WASM binary.");
-	}
+	wasm_gc::garbage_collect_file(&wasm_file, &wasm_compact_file)
+		.expect("Failed to compact generated WASM binary.");
 
 	(WasmBinary(wasm_compact_file), WasmBinaryBloaty(wasm_file))
 }