Merge pull request #20 from paritytech/runtime-type-build

Runtime type injection implemention

Cargo.toml

@@ -10,6 +10,7 @@ env_logger = "0.4"
 lazy_static = "0.2"
 clap = "2.24"
 glob = "0.2"
+byteorder = "1"
 
 [lib]
 

build/src/main.rs

@@ -76,6 +76,14 @@ fn main() {
 		.arg(Arg::with_name("skip_alloc")
 			.help("Skip allocator externalizer step producing final wasm")
 			.long("skip-externalize"))
+		.arg(Arg::with_name("runtime_type")
+			.help("Injects RUNTIME_TYPE global export")
+			.takes_value(true)
+			.long("runtime-type"))
+		.arg(Arg::with_name("runtime_version")
+			.help("Injects RUNTIME_VERSION global export")
+			.takes_value(true)
+			.long("runtime-version"))
 		.get_matches();
 
     let target_dir = matches.value_of("target").expect("is required; qed");
@@ -98,5 +106,15 @@ fn main() {
 		wasm_utils::optimize(&mut module, vec!["_call", "setTempRet0"]).expect("Optimizer to finish without errors");
 	}
 
+	if let Some(runtime_type) = matches.value_of("runtime_type") {
+		let runtime_type: &[u8] = runtime_type.as_bytes();
+		if runtime_type.len() != 4 {
+			panic!("--runtime-type should be equal to 4 bytes");
+		}
+		let runtime_version: u32 = matches.value_of("runtime_version").unwrap_or("1").parse()
+			.expect("--runtime-version should be a positive integer");
+		module = wasm_utils::inject_runtime_type(module, &runtime_type, runtime_version);
+	}
+
 	parity_wasm::serialize_to_file(&path, module).unwrap();
-}
+}

src/lib.rs

@@ -1,5 +1,6 @@
 extern crate parity_wasm;
 extern crate env_logger;
+extern crate byteorder;
 #[macro_use] extern crate log;
 #[macro_use] extern crate lazy_static;
 
@@ -12,6 +13,7 @@ mod logger;
 mod ext;
 mod pack;
 mod nondeterminism_check;
+mod runtime_type;
 
 pub use optimizer::{optimize, Error as OptimizerError};
 pub use gas::inject_gas_counter;
@@ -19,3 +21,4 @@ pub use logger::init_log;
 pub use ext::externalize;
 pub use pack::pack_instance;
 pub use nondeterminism_check::is_deterministic;
+pub use runtime_type::inject_runtime_type;

src/nondeterminism_check.rs

@@ -120,7 +120,7 @@ mod tests {
 	#[test]
 	fn nondeterminism_not() {
 		let module = builder::module()
-			.function().signature().return_type().f32().build()
+			.function().signature().return_type().i32().build()
 			.body()
 				.with_opcodes(elements::Opcodes::new(
 					vec![

src/runtime_type.rs

@@ -0,0 +1,43 @@
+use parity_wasm::{elements, builder};
+use self::elements::{ Module, GlobalEntry, External, ExportEntry, GlobalType, ValueType, InitExpr, Opcode, Internal };
+use byteorder::{ LittleEndian, ByteOrder };
+
+pub fn inject_runtime_type(module: Module, runtime_type: &[u8], runtime_version: u32) -> Module {
+	let runtime_type: u32 = LittleEndian::read_u32(&runtime_type);
+	let globals_count: u32 = match module.global_section() {
+		Some(ref section) => section.entries().len() as u32,
+		None => 0
+	};
+	let imported_globals_count: u32 = match module.import_section() {
+		Some(ref section) => section.entries().iter().filter(|e| match *e.external() {
+			External::Global(ref _a) => true,
+			_ => false
+		}).count() as u32,
+		None => 0
+	};
+	let total_globals_count: u32 = globals_count + imported_globals_count;
+
+	builder::from_module(module)
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const(runtime_type as i32), Opcode::End])))
+		.with_export(ExportEntry::new("RUNTIME_TYPE".into(), Internal::Global(total_globals_count)))
+		.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const(runtime_version as i32), Opcode::End])))
+		.with_export(ExportEntry::new("RUNTIME_VERSION".into(), Internal::Global(total_globals_count + 1)))
+	.build()
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	#[test]
+	fn it_injects() {
+		let mut module = builder::module()
+			.with_global(GlobalEntry::new(GlobalType::new(ValueType::I32, false), InitExpr::new(vec![Opcode::I32Const(42 as i32)])))
+		.build();
+		module = inject_runtime_type(module, b"emcc", 1);
+		let global_section = module.global_section().expect("Global section expected");
+		assert_eq!(3, global_section.entries().len());
+		let export_section = module.export_section().expect("Export section expected");
+		assert!(export_section.entries().iter().find(|e| e.field() == "RUNTIME_TYPE" ).is_some());
+		assert!(export_section.entries().iter().find(|e| e.field() == "RUNTIME_VERSION" ).is_some());
+	}
+}