cli: CLI option for running Substrate with compiled Wasm execution.

Cargo.toml

@@ -133,3 +133,9 @@ is-it-maintained-open-issues = { repository = "paritytech/substrate" }
 [profile.release]
 # Substrate runtime requires unwinding.
 panic = "unwind"
+
+[features]
+wasmtime = [
+    "cli/wasmtime",
+]
+

core/cli/Cargo.toml

@@ -38,3 +38,8 @@ rpassword = "4.0.1"
 
 [dev-dependencies]
 tempdir = "0.3.7"
+
+[features]
+wasmtime = [
+    "service/wasmtime",
+]

core/cli/src/params.rs

@@ -50,13 +50,32 @@ arg_enum! {
 	pub enum WasmExecutionMethod {
 		// Uses an interpreter.
 		Interpreted,
+		// Uses a compiled runtime.
+		Compiled,
+	}
+}
+
+impl WasmExecutionMethod {
+	/// Returns list of variants that are not disabled by feature flags.
+	fn enabled_variants() -> Vec<&'static str> {
+		Self::variants()
+			.iter()
+			.cloned()
+			.filter(|&name| cfg!(feature = "wasmtime") || name != "Compiled")
+			.collect()
 	}
 }
 
 impl Into<service::config::WasmExecutionMethod> for WasmExecutionMethod {
 	fn into(self) -> service::config::WasmExecutionMethod {
 		match self {
 			WasmExecutionMethod::Interpreted => service::config::WasmExecutionMethod::Interpreted,
+			#[cfg(feature = "wasmtime")]
+			WasmExecutionMethod::Compiled => service::config::WasmExecutionMethod::Compiled,
+			#[cfg(not(feature = "wasmtime"))]
+			WasmExecutionMethod::Compiled => panic!(
+				"Substrate must be compiled with \"wasmtime\" feature for compiled Wasm execution"
+			),
 		}
 	}
 }
@@ -407,7 +426,7 @@ pub struct RunCmd {
 	#[structopt(
 		long = "wasm-execution",
 		value_name = "METHOD",
-		possible_values = &WasmExecutionMethod::variants(),
+		possible_values = &WasmExecutionMethod::enabled_variants(),
 		case_insensitive = true,
 		default_value = "Interpreted"
 	)]

core/service/Cargo.toml

@@ -48,3 +48,8 @@ babe-primitives = { package = "substrate-consensus-babe-primitives", path = "../
 grandpa = { package = "substrate-finality-grandpa", path = "../../core/finality-grandpa" }
 grandpa-primitives = { package = "substrate-finality-grandpa-primitives", path = "../../core/finality-grandpa/primitives" }
 tokio = "0.1"
+
+[features]
+wasmtime = [
+    "substrate-executor/wasmtime",
+]

node/cli/Cargo.toml

@@ -63,3 +63,10 @@ tempfile = "3.1.0"
 [build-dependencies]
 cli = { package = "substrate-cli", path = "../../core/cli" }
 structopt = "0.3.3"
+
+[features]
+wasmtime = [
+    "cli/wasmtime",
+    "node-executor/wasmtime",
+    "substrate-service/wasmtime",
+]