Removed panics on missing memory

core/executor/src/wasm_executor.rs

@@ -636,13 +636,20 @@ impl WasmExecutor {
 		method: &str,
 		data: &[u8],
 		) -> Result<Vec<u8>> {
-		let module = ::wasmi::Module::from_buffer(code)
-			.expect("all modules compiled with rustc are valid wasm code; qed");
-		let module = self.prepare_module(ext, heap_pages, &module)
-			.expect("all modules compiled with rustc are valid wasm code; qed");
+		let module = ::wasmi::Module::from_buffer(code)?;
+		let module = self.prepare_module(ext, heap_pages, &module)?;
 		self.call_in_wasm_module(ext, &module, method, data)
 	}
 
+	fn get_mem_instance(module: &ModuleRef) -> Result<MemoryRef> {
+		Ok(module
+			.export_by_name("memory")
+			.ok_or_else(|| Error::from(ErrorKind::InvalidMemoryReference))?
+			.as_memory()
+			.ok_or_else(|| Error::from(ErrorKind::InvalidMemoryReference))?
+			.clone())
+	}
+
 	/// Call a given method in the given wasm-module runtime.
 	pub fn call_in_wasm_module<E: Externalities<Blake2Hasher>>(
 		&self,
@@ -653,14 +660,7 @@ impl WasmExecutor {
 	) -> Result<Vec<u8>> {
 		// extract a reference to a linear memory, optional reference to a table
 		// and then initialize FunctionExecutor.
-		let memory = module_instance
-			.export_by_name("memory")
-			// TODO: with code coming from the blockchain it isn't strictly been compiled with rustc anymore.
-			// these assumptions are probably not true anymore
-			.expect("all modules compiled with rustc should have an export named 'memory'; qed")
-			.as_memory()
-			.expect("in module generated by rustc export named 'memory' should be a memory; qed")
-			.clone();
+		let memory = Self::get_mem_instance(module_instance)?;
 		let table: Option<TableRef> = module_instance
 			.export_by_name("__indirect_function_table")
 			.and_then(|e| e.as_table().cloned());
@@ -721,15 +721,7 @@ impl WasmExecutor {
 
 		// extract a reference to a linear memory, optional reference to a table
 		// and then initialize FunctionExecutor.
-		let memory = intermediate_instance
-			.not_started_instance()
-			.export_by_name("memory")
-			// TODO: with code coming from the blockchain it isn't strictly been compiled with rustc anymore.
-			// these assumptions are probably not true anymore
-			.expect("all modules compiled with rustc should have an export named 'memory'; qed")
-			.as_memory()
-			.expect("in module generated by rustc export named 'memory' should be a memory; qed")
-			.clone();
+		let memory = Self::get_mem_instance(intermediate_instance.not_started_instance())?;
 		memory.grow(Pages(heap_pages)).map_err(|_| Error::from(ErrorKind::Runtime))?;
 		let table: Option<TableRef> = intermediate_instance
 			.not_started_instance()