compiler, reflect, runtime: Implement method values in reflect.

From-SVN: r205913

gcc/go/gofrontend/types.cc

@@ -2261,26 +2261,9 @@ Type::method_constructor(Gogo*, Type* method_type,
 
   ++p;
   go_assert(p->is_field_name("typ"));
-  if (!only_value_methods && m->is_value_method())
-    {
-      // This is a value method on a pointer type.  Change the type of
-      // the method to use a pointer receiver.  The implementation
-      // always uses a pointer receiver anyhow.
-      Type* rtype = mtype->receiver()->type();
-      Type* prtype = Type::make_pointer_type(rtype);
-      Typed_identifier* receiver =
-	new Typed_identifier(mtype->receiver()->name(), prtype,
-			     mtype->receiver()->location());
-      mtype = Type::make_function_type(receiver,
-				       (mtype->parameters() == NULL
-					? NULL
-					: mtype->parameters()->copy()),
-				       (mtype->results() == NULL
-					? NULL
-					: mtype->results()->copy()),
-				       mtype->location());
-    }
-  vals->push_back(Expression::make_type_descriptor(mtype, bloc));
+  bool want_pointer_receiver = !only_value_methods && m->is_value_method();
+  nonmethod_type = mtype->copy_with_receiver_as_param(want_pointer_receiver);
+  vals->push_back(Expression::make_type_descriptor(nonmethod_type, bloc));
 
   ++p;
   go_assert(p->is_field_name("tfn"));
@@ -4008,6 +3991,32 @@ Function_type::copy_with_receiver(Type* receiver_type) const
   return ret;
 }
 
+// Make a copy of a function type with the receiver as the first
+// parameter.
+
+Function_type*
+Function_type::copy_with_receiver_as_param(bool want_pointer_receiver) const
+{
+  go_assert(this->is_method());
+  Typed_identifier_list* new_params = new Typed_identifier_list();
+  Type* rtype = this->receiver_->type();
+  if (want_pointer_receiver)
+    rtype = Type::make_pointer_type(rtype);
+  Typed_identifier receiver(this->receiver_->name(), rtype,
+			    this->receiver_->location());
+  new_params->push_back(receiver);
+  const Typed_identifier_list* orig_params = this->parameters_;
+  if (orig_params != NULL && !orig_params->empty())
+    {
+      for (Typed_identifier_list::const_iterator p = orig_params->begin();
+	   p != orig_params->end();
+	   ++p)
+	new_params->push_back(*p);
+    }
+  return Type::make_function_type(NULL, new_params, this->results_,
+				  this->location_);
+}
+
 // Make a copy of a function type ignoring any receiver and adding a
 // closure parameter.
 

gcc/go/gofrontend/types.h

@@ -1797,6 +1797,12 @@ class Function_type : public Type
   Function_type*
   copy_with_receiver(Type*) const;
 
+  // Return a copy of this type with the receiver treated as the first
+  // parameter.  If WANT_POINTER_RECEIVER is true, the receiver is
+  // forced to be a pointer.
+  Function_type*
+  copy_with_receiver_as_param(bool want_pointer_receiver) const;
+
   // Return a copy of this type ignoring any receiver and using dummy
   // names for all parameters.  This is used for thunks for method
   // values.

libgo/go/reflect/all_test.go

@@ -1631,9 +1631,13 @@ func TestMethod(t *testing.T) {
 	}
 }
 
-/* Not yet implemented for gccgo
-
 func TestMethodValue(t *testing.T) {
+	switch runtime.GOARCH {
+	case "amd64", "386":
+	default:
+		t.Skip("reflect method values not implemented for " + runtime.GOARCH)
+	}
+
 	p := Point{3, 4}
 	var i int64
 
@@ -1721,8 +1725,6 @@ func TestMethodValue(t *testing.T) {
 	}
 }
 
-*/
-
 // Reflect version of $GOROOT/test/method5.go
 
 // Concrete types implementing M method.
@@ -1807,14 +1809,18 @@ type Tm4 struct {
 func (t4 Tm4) M(x int, b byte) (byte, int) { return b, x + 40 }
 
 func TestMethod5(t *testing.T) {
-	/* Not yet used for gccgo
+	switch runtime.GOARCH {
+	case "amd64", "386":
+	default:
+		t.Skip("reflect method values not implemented for " + runtime.GOARCH)
+	}
+
 	CheckF := func(name string, f func(int, byte) (byte, int), inc int) {
 		b, x := f(1000, 99)
 		if b != 99 || x != 1000+inc {
 			t.Errorf("%s(1000, 99) = %v, %v, want 99, %v", name, b, x, 1000+inc)
 		}
 	}
-	*/
 
 	CheckV := func(name string, i Value, inc int) {
 		bx := i.Method(0).Call([]Value{ValueOf(1000), ValueOf(byte(99))})
@@ -1824,9 +1830,7 @@ func TestMethod5(t *testing.T) {
 			t.Errorf("direct %s.M(1000, 99) = %v, %v, want 99, %v", name, b, x, 1000+inc)
 		}
 
-		/* Not yet implemented for gccgo
 		CheckF(name+".M", i.Method(0).Interface().(func(int, byte) (byte, int)), inc)
-		*/
 	}
 
 	var TinterType = TypeOf(new(Tinter)).Elem()

libgo/go/reflect/makefunc.go

@@ -17,6 +17,11 @@ type makeFuncImpl struct {
 	code uintptr
 	typ  *funcType
 	fn   func([]Value) []Value
+
+	// For gccgo we use the same entry point for functions and for
+	// method values.
+	method int
+	rcvr   Value
 }
 
 // MakeFunc returns a new function of the given Type
@@ -61,7 +66,7 @@ func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value {
 	dummy := makeFuncStub
 	code := **(**uintptr)(unsafe.Pointer(&dummy))
 
-	impl := &makeFuncImpl{code: code, typ: ftyp, fn: fn}
+	impl := &makeFuncImpl{code: code, typ: ftyp, fn: fn, method: -1}
 
 	return Value{t, unsafe.Pointer(&impl), flag(Func<<flagKindShift) | flagIndir}
 }
@@ -85,15 +90,94 @@ func makeMethodValue(op string, v Value) Value {
 		panic("reflect: internal error: invalid use of makePartialFunc")
 	}
 
+	switch runtime.GOARCH {
+	case "amd64", "386":
+	default:
+		panic("reflect.makeMethodValue not implemented for " + runtime.GOARCH)
+	}
+
 	// Ignoring the flagMethod bit, v describes the receiver, not the method type.
 	fl := v.flag & (flagRO | flagAddr | flagIndir)
 	fl |= flag(v.typ.Kind()) << flagKindShift
 	rcvr := Value{v.typ, v.val, fl}
 
+	// v.Type returns the actual type of the method value.
+	ft := v.Type().(*rtype)
+
+	// Indirect Go func value (dummy) to obtain
+	// actual code address. (A Go func value is a pointer
+	// to a C function pointer. http://golang.org/s/go11func.)
+	dummy := makeFuncStub
+	code := **(**uintptr)(unsafe.Pointer(&dummy))
+
 	// Cause panic if method is not appropriate.
 	// The panic would still happen during the call if we omit this,
 	// but we want Interface() and other operations to fail early.
-	methodReceiver(op, rcvr, int(v.flag)>>flagMethodShift)
+	t, _, _ := methodReceiver(op, rcvr, int(v.flag)>>flagMethodShift)
 
-	panic("reflect makeMethodValue not implemented")
+	fv := &makeFuncImpl{
+		code:   code,
+		typ:    (*funcType)(unsafe.Pointer(t)),
+		method: int(v.flag) >> flagMethodShift,
+		rcvr:   rcvr,
+	}
+
+	return Value{ft, unsafe.Pointer(&fv), v.flag&flagRO | flag(Func)<<flagKindShift | flagIndir}
+}
+
+// makeValueMethod takes a method function and returns a function that
+// takes a value receiver and calls the real method with a pointer to
+// it.
+func makeValueMethod(v Value) Value {
+	typ := v.typ
+	if typ.Kind() != Func {
+		panic("reflect: call of makeValueMethod with non-Func type")
+	}
+	if v.flag&flagMethodFn == 0 {
+		panic("reflect: call of makeValueMethod with non-MethodFn")
+	}
+
+	switch runtime.GOARCH {
+	case "amd64", "386":
+	default:
+		panic("reflect.makeValueMethod not implemented for " + runtime.GOARCH)
+	}
+
+	t := typ.common()
+	ftyp := (*funcType)(unsafe.Pointer(t))
+
+	// Indirect Go func value (dummy) to obtain
+	// actual code address. (A Go func value is a pointer
+	// to a C function pointer. http://golang.org/s/go11func.)
+	dummy := makeFuncStub
+	code := **(**uintptr)(unsafe.Pointer(&dummy))
+
+	impl := &makeFuncImpl{
+		code:   code,
+		typ:    ftyp,
+		method: -2,
+		rcvr:   v,
+	}
+
+	return Value{t, unsafe.Pointer(&impl), flag(Func<<flagKindShift) | flagIndir}
+}
+
+// Call the function represented by a makeFuncImpl.
+func (c *makeFuncImpl) call(in []Value) []Value {
+	if c.method == -1 {
+		return c.fn(in)
+	} else if c.method == -2 {
+		if c.typ.IsVariadic() {
+			return c.rcvr.CallSlice(in)
+		} else {
+			return c.rcvr.Call(in)
+		}
+	} else {
+		m := c.rcvr.Method(c.method)
+		if c.typ.IsVariadic() {
+			return m.CallSlice(in)
+		} else {
+			return m.Call(in)
+		}
+	}
 }

libgo/go/reflect/makefuncgo_386.go

@@ -80,7 +80,7 @@ func MakeFuncStubGo(regs *i386Regs, c *makeFuncImpl) {
 
 	// Call the real function.
 
-	out := c.fn(in)
+	out := c.call(in)
 
 	if len(out) != len(ftyp.out) {
 		panic("reflect: wrong return count from function created by MakeFunc")

libgo/go/reflect/makefuncgo_amd64.go

@@ -319,7 +319,7 @@ argloop:
 	// All the real arguments have been found and turned into
 	// Value's.  Call the real function.
 
-	out := c.fn(in)
+	out := c.call(in)
 
 	if len(out) != len(ftyp.out) {
 		panic("reflect: wrong return count from function created by MakeFunc")

libgo/go/reflect/type.go

@@ -517,7 +517,7 @@ func (t *uncommonType) Method(i int) (m Method) {
 	m.Type = toType(mt)
 	x := new(unsafe.Pointer)
 	*x = unsafe.Pointer(&p.tfn)
-	m.Func = Value{mt, unsafe.Pointer(x), fl | flagIndir}
+	m.Func = Value{mt, unsafe.Pointer(x), fl | flagIndir | flagMethodFn}
 	m.Index = i
 	return
 }

libgo/go/reflect/value.go

@@ -98,6 +98,7 @@ const (
 	flagIndir
 	flagAddr
 	flagMethod
+	flagMethodFn         // gccgo: first fn parameter is always pointer
 	flagKindShift        = iota
 	flagKindWidth        = 5 // there are 27 kinds
 	flagKindMask    flag = 1<<flagKindWidth - 1
@@ -433,7 +434,7 @@ func (v Value) call(op string, in []Value) []Value {
 	if v.flag&flagMethod != 0 {
 		nin++
 	}
-	firstPointer := len(in) > 0 && t.In(0).Kind() != Ptr && v.flag&flagMethod == 0 && isMethod(v.typ)
+	firstPointer := len(in) > 0 && t.In(0).Kind() != Ptr && v.flag&flagMethodFn != 0
 	params := make([]unsafe.Pointer, nin)
 	off := 0
 	if v.flag&flagMethod != 0 {
@@ -484,33 +485,6 @@ func (v Value) call(op string, in []Value) []Value {
 	return ret
 }
 
-// gccgo specific test to see if typ is a method.  We can tell by
-// looking at the string to see if there is a receiver.  We need this
-// because for gccgo all methods take pointer receivers.
-func isMethod(t *rtype) bool {
-	if Kind(t.kind) != Func {
-		return false
-	}
-	s := *t.string
-	parens := 0
-	params := 0
-	sawRet := false
-	for i, c := range s {
-		if c == '(' {
-			if parens == 0 {
-				params++
-			}
-			parens++
-		} else if c == ')' {
-			parens--
-		} else if parens == 0 && c == ' ' && s[i+1] != '(' && !sawRet {
-			params++
-			sawRet = true
-		}
-	}
-	return params > 2
-}
-
 // methodReceiver returns information about the receiver
 // described by v. The Value v may or may not have the
 // flagMethod bit set, so the kind cached in v.flag should
@@ -873,6 +847,16 @@ func valueInterface(v Value, safe bool) interface{} {
 		v = makeMethodValue("Interface", v)
 	}
 
+	if v.flag&flagMethodFn != 0 {
+		if v.typ.Kind() != Func {
+			panic("reflect: MethodFn of non-Func")
+		}
+		ft := (*funcType)(unsafe.Pointer(v.typ))
+		if ft.in[0].Kind() != Ptr {
+			v = makeValueMethod(v)
+		}
+	}
+
 	k := v.kind()
 	if k == Interface {
 		// Special case: return the element inside the interface.
@@ -1187,8 +1171,7 @@ func (v Value) Pointer() uintptr {
 			// created via reflect have the same underlying code pointer,
 			// so their Pointers are equal. The function used here must
 			// match the one used in makeMethodValue.
-			// This is not properly implemented for gccgo.
-			f := Zero
+			f := makeFuncStub
 			return **(**uintptr)(unsafe.Pointer(&f))
 		}
 		p := v.val

libgo/runtime/go-recover.c

@@ -84,6 +84,11 @@ __go_can_recover (const void *retaddr)
   if (name[0] == 'f' && name[1] == 'f' && name[2] == 'i' && name[3] == '_')
     return 1;
 
+  /* We may also be called by reflect.makeFuncImpl.call, for a
+     function created by reflect.MakeFunc.  */
+  if (__builtin_strstr ((const char *) name, "makeFuncImpl") != NULL)
+    return 1;
+
   return 0;
 }