runtime type injection implemented #10

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());
+	}
+}