interp: allow externref params for calls to/from guest modules

Signed-off-by: deadprogram <[email protected]>

interp/tester/instance.go

@@ -2,10 +2,16 @@ package tester
 
 import (
 	"testing"
+	"unsafe"
 
 	"github.com/hybridgroup/mechanoid/engine"
 )
 
+type testingType struct {
+	val1 string
+	val2 string
+}
+
 func InstanceTest(t *testing.T, i engine.Interpreter) {
 	if err := i.Init(); err != nil {
 		t.Errorf("Interpreter.Init() failed: %v", err)
@@ -45,7 +51,7 @@ func InstanceTest(t *testing.T, i engine.Interpreter) {
 		if err != nil {
 			t.Errorf("Instance.Call() failed: %v", err)
 		}
-		if int64(results.(int32)) != int64(3) {
+		if int64(results.(int64)) != int64(3) {
 			t.Errorf("Instance.Call() failed: %v", results)
 		}
 	})
@@ -55,7 +61,7 @@ func InstanceTest(t *testing.T, i engine.Interpreter) {
 		if err != nil {
 			t.Errorf("Instance.Call() failed: %v", err)
 		}
-		if uint64(results.(int32)) != uint64(3) {
+		if uint64(results.(int64)) != uint64(3) {
 			t.Errorf("Instance.Call() failed: %v", results)
 		}
 	})
@@ -79,4 +85,21 @@ func InstanceTest(t *testing.T, i engine.Interpreter) {
 			t.Errorf("Instance.Call() failed: %v", results)
 		}
 	})
+
+	t.Run("Call externref", func(t *testing.T) {
+		thing := testingType{val1: "hello", val2: "world"}
+
+		// This is a hack to get the pointer value as an int32
+		// Externelref is an opaque type, so we can't do anything with it
+		// We just want to make sure that the pointer value is passed through correctly
+		ptr := uintptr(unsafe.Pointer(&thing)) & 0xFFFFFFFF
+
+		results, err := inst.Call("test_externref", ptr)
+		if err != nil {
+			t.Errorf("Instance.Call() failed: %v", err)
+		}
+		if uintptr(results.(int32)) != ptr {
+			t.Errorf("Instance.Call() incorrect: %v %v", ptr, results)
+		}
+	})
 }

interp/wasman/instance.go

@@ -64,6 +64,8 @@ func encodeArg(arg any) uint64 {
 		return uint64(val)
 	case uint64:
 		return uint64(val)
+	case uintptr:
+		return uint64(val)
 	}
 	panic("bad arg type")
 }
@@ -86,7 +88,9 @@ func decodeResult(result uint64, vtype types.ValueType) any {
 	case types.ValueTypeI32:
 		return int32(result)
 	case types.ValueTypeI64:
-		return int32(result)
+		return int64(result)
+	case types.ValueTypeExternref:
+		return uintptr(result)
 	}
 	panic("unreachable")
 }

interp/wazero/instance.go

@@ -53,6 +53,8 @@ func encodeArg(arg any) uint64 {
 		return api.EncodeU32(val)
 	case uint64:
 		return uint64(val)
+	case uintptr:
+		return api.EncodeExternref(val)
 	}
 	panic("bad arg type")
 }
@@ -75,7 +77,9 @@ func decodeResult(result uint64, vtype api.ValueType) any {
 	case api.ValueTypeI32:
 		return api.DecodeI32(result)
 	case api.ValueTypeI64:
-		return api.DecodeI32(result)
+		return int64(result)
+	case api.ValueTypeExternref:
+		return api.DecodeExternref(result)
 	}
 	panic("unreachable")
 }