compiler: add munmap finalizer on cache hits to avoid memory leak

Signed-off-by: Val Packett <[email protected]>

internal/engine/compiler/engine.go

@@ -523,7 +523,9 @@ func (e *engine) Close() (err error) {
 
 // CompileModule implements the same method as documented on wasm.Engine.
 func (e *engine) CompileModule(_ context.Context, module *wasm.Module, listeners []experimental.FunctionListener, ensureTermination bool) error {
-	if _, ok, err := e.getCompiledModule(module, listeners); ok { // cache hit!
+	if cm, ok, err := e.getCompiledModule(module, listeners); ok { // cache hit!
+		// As this uses mmap, we need to munmap on the compiled machine code when it's GCed.
+		e.setFinalizer(cm, releaseCompiledModule)
 		return nil
 	} else if err != nil {
 		return err