FuncInstances hold WeakRef

src/func.rs

@@ -1,4 +1,4 @@
-use std::rc::Rc;
+use std::rc::{Rc, Weak};
 use std::fmt;
 use std::collections::HashMap;
 use std::borrow::Cow;
@@ -7,7 +7,7 @@ use {Error, Signature};
 use host::Externals;
 use runner::{prepare_function_args, FunctionContext, Interpreter};
 use value::RuntimeValue;
-use module::ModuleRef;
+use module::ModuleInstance;
 use common::stack::StackWithLimit;
 use common::{DEFAULT_FRAME_STACK_LIMIT, DEFAULT_VALUE_STACK_LIMIT};
 
@@ -36,7 +36,7 @@ impl FuncRef {
 pub(crate) enum FuncInstance {
 	Internal {
 		signature: Rc<Signature>,
-		module: ModuleRef,
+		module: Weak<ModuleInstance>,
 		body: Rc<FuncBody>,
 	},
 	Host {
@@ -69,7 +69,7 @@ impl fmt::Debug for FuncInstance {
 
 impl FuncInstance {
 	pub(crate) fn alloc_internal(
-		module: ModuleRef,
+		module: Weak<ModuleInstance>,
 		signature: Rc<Signature>,
 		body: FuncBody,
 	) -> FuncRef {

src/module.rs

@@ -15,7 +15,7 @@ use common::{DEFAULT_MEMORY_INDEX, DEFAULT_TABLE_INDEX};
 use types::{GlobalDescriptor, TableDescriptor, MemoryDescriptor};
 
 #[derive(Clone, Debug)]
-pub struct ModuleRef(Rc<ModuleInstance>);
+pub struct ModuleRef(pub(crate) Rc<ModuleInstance>);
 
 impl ::std::ops::Deref for ModuleRef {
 	type Target = ModuleInstance;
@@ -253,7 +253,7 @@ impl ModuleInstance {
 					labels: labels,
 				};
 				let func_instance =
-					FuncInstance::alloc_internal(instance.clone(), signature, func_body);
+					FuncInstance::alloc_internal(Rc::downgrade(&instance.0), signature, func_body);
 				instance.push_func(func_instance);
 			}
 		}

src/runner.rs

@@ -1008,13 +1008,13 @@ impl<'a, E: Externals> Interpreter<'a, E> {
 impl FunctionContext {
 	pub fn new<'store>(function: FuncRef, value_stack_limit: usize, frame_stack_limit: usize, signature: &Signature, args: Vec<RuntimeValue>) -> Self {
 		let module = match *function.as_instance() {
-			FuncInstance::Internal { ref module, .. } => module.clone(),
+			FuncInstance::Internal { ref module, .. } => module.upgrade().expect("module deallocated"),
 			FuncInstance::Host { .. } => panic!("Host functions can't be called as internally defined functions; Thus FunctionContext can be created only with internally defined functions; qed"),
 		};
 		FunctionContext {
 			is_initialized: false,
 			function: function,
-			module: module,
+			module: ModuleRef(module),
 			return_type: signature.return_type().map(|vt| BlockType::Value(vt.into_elements())).unwrap_or(BlockType::NoResult),
 			value_stack: StackWithLimit::with_limit(value_stack_limit),
 			frame_stack: StackWithLimit::with_limit(frame_stack_limit),
@@ -1026,7 +1026,7 @@ impl FunctionContext {
 	pub fn nested(&mut self, function: FuncRef) -> Result<Self, Error> {
 		let (function_locals, module, function_return_type) = {
 			let module = match *function.as_instance() {
-				FuncInstance::Internal { ref module, .. } => module.clone(),
+				FuncInstance::Internal { ref module, .. } => module.upgrade().expect("module deallocated"),
 				FuncInstance::Host { .. } => panic!("Host functions can't be called as internally defined functions; Thus FunctionContext can be created only with internally defined functions; qed"),
 			};
 			let function_type = function.signature();
@@ -1038,7 +1038,7 @@ impl FunctionContext {
 		Ok(FunctionContext {
 			is_initialized: false,
 			function: function,
-			module: module,
+			module: ModuleRef(module),
 			return_type: function_return_type,
 			value_stack: StackWithLimit::with_limit(self.value_stack.limit() - self.value_stack.len()),
 			frame_stack: StackWithLimit::with_limit(self.frame_stack.limit() - self.frame_stack.len()),