compiler,reflect: fix NumMethods for Interface type

Author: frenkel26

compiler/interface.go

@@ -124,16 +124,19 @@ func (c *compilerContext) pkgPathPtr(pkgpath string) llvm.Value {
 func (c *compilerContext) getTypeCode(typ types.Type) llvm.Value {
 	ms := c.program.MethodSets.MethodSet(typ)
 	hasMethodSet := ms.Len() != 0
-	if _, ok := typ.Underlying().(*types.Interface); ok {
+	_, isInterface := typ.Underlying().(*types.Interface)
+	if isInterface {
 		hasMethodSet = false
 	}
 
+	// As defined in https://pkg.go.dev/reflect#Type:
+	// NumMethod returns the number of methods accessible using Method.
+	// For a non-interface type, it returns the number of exported methods.
+	// For an interface type, it returns the number of exported and unexported methods.
 	var numMethods int
-	if hasMethodSet {
-		for i := 0; i < ms.Len(); i++ {
-			if ms.At(i).Obj().Exported() {
-				numMethods++
-			}
+	for i := 0; i < ms.Len(); i++ {
+		if isInterface || ms.At(i).Obj().Exported() {
+			numMethods++
 		}
 	}
 

compiler/testdata/interface.ll

@@ -9,7 +9,7 @@ target triple = "wasm32-unknown-wasi"
 @"reflect/types.type:basic:int" = linkonce_odr constant { i8, ptr } { i8 -62, ptr @"reflect/types.type:pointer:basic:int" }, align 4
 @"reflect/types.type:pointer:basic:int" = linkonce_odr constant { i8, i16, ptr } { i8 -43, i16 0, ptr @"reflect/types.type:basic:int" }, align 4
 @"reflect/types.type:pointer:named:error" = linkonce_odr constant { i8, i16, ptr } { i8 -43, i16 0, ptr @"reflect/types.type:named:error" }, align 4
-@"reflect/types.type:named:error" = linkonce_odr constant { i8, i16, ptr, ptr, ptr, [7 x i8] } { i8 116, i16 0, ptr @"reflect/types.type:pointer:named:error", ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}", ptr @"reflect/types.type.pkgpath.empty", [7 x i8] c".error\00" }, align 4
+@"reflect/types.type:named:error" = linkonce_odr constant { i8, i16, ptr, ptr, ptr, [7 x i8] } { i8 116, i16 1, ptr @"reflect/types.type:pointer:named:error", ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}", ptr @"reflect/types.type.pkgpath.empty", [7 x i8] c".error\00" }, align 4
 @"reflect/types.type.pkgpath.empty" = linkonce_odr unnamed_addr constant [1 x i8] zeroinitializer, align 1
 @"reflect/types.type:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant { i8, ptr } { i8 84, ptr @"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}" }, align 4
 @"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant { i8, i16, ptr } { i8 -43, i16 0, ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}" }, align 4

testdata/reflect.go

@@ -456,6 +456,7 @@ func showValue(rv reflect.Value, indent string) {
 	case reflect.Interface:
 		println(indent + "  interface")
 		println(indent+"  nil:", rv.IsNil())
+		println(indent+"  NumMethod:", rv.NumMethod())
 		if !rv.IsNil() {
 			showValue(rv.Elem(), indent+"  ")
 		}

testdata/reflect.txt

@@ -80,6 +80,7 @@ reflect type: ptr
   reflect type: interface settable=true addrable=true
     interface
     nil: true
+    NumMethod: 1
 reflect type: ptr
   pointer: true int
   nil: false
@@ -240,6 +241,7 @@ reflect type: struct
   reflect type: interface caninterface=false
     interface
     nil: true
+    NumMethod: 1
 reflect type: struct
   struct: 3
   field: 0 a
@@ -371,12 +373,14 @@ reflect type: slice comparable=false
   reflect type: interface settable=true addrable=true
     interface
     nil: false
+    NumMethod: 0
     reflect type: int
       int: 3
   indexing: 1
   reflect type: interface settable=true addrable=true
     interface
     nil: false
+    NumMethod: 0
     reflect type: string
       string: str 3
       reflect type: uint8
@@ -389,6 +393,7 @@ reflect type: slice comparable=false
   reflect type: interface settable=true addrable=true
     interface
     nil: false
+    NumMethod: 0
     reflect type: complex128
       complex: (-4.000000e+000+2.500000e+000i)
 reflect type: ptr