libgo: update to Go 1.8 release candidate 1

    
    Compiler changes:
      * Change map assignment to use mapassign and assign value directly.
      * Change string iteration to use decoderune, faster for ASCII strings.
      * Change makeslice to take int, and use makeslice64 for larger values.
      * Add new noverflow field to hmap struct used for maps.
    
    Unresolved problems, to be fixed later:
      * Commented out test in go/types/sizes_test.go that doesn't compile.
      * Commented out reflect.TestStructOf test for padding after zero-sized field.
    
    Reviewed-on: https://go-review.googlesource.com/35231

gotools/:
	Updates for Go 1.8rc1.
	* Makefile.am (go_cmd_go_files): Add bug.go.
	(s-zdefaultcc): Write defaultPkgConfig.
	* Makefile.in: Rebuild.

From-SVN: r244456

1 files changed, 95 insertions, 34 deletions

diff --git a/libgo/go/encoding/json/decode.go b/libgo/go/encoding/json/decode.go
index 2eda875..77fc460 100644
--- a/libgo/go/encoding/json/decode.go
+++ b/libgo/go/encoding/json/decode.go
@@ -34,6 +34,13 @@ import (
 // the value pointed at by the pointer. If the pointer is nil, Unmarshal
 // allocates a new value for it to point to.
 //
+// To unmarshal JSON into a value implementing the Unmarshaler interface,
+// Unmarshal calls that value's UnmarshalJSON method, including
+// when the input is a JSON null.
+// Otherwise, if the value implements encoding.TextUnmarshaler
+// and the input is a JSON quoted string, Unmarshal calls that value's
+// UnmarshalText method with the unquoted form of the string.
+//
 // To unmarshal JSON into a struct, Unmarshal matches incoming object
 // keys to the keys used by Marshal (either the struct field name or its tag),
 // preferring an exact match but also accepting a case-insensitive match.
@@ -63,8 +70,8 @@ import (
 //
 // To unmarshal a JSON object into a map, Unmarshal first establishes a map to
 // use. If the map is nil, Unmarshal allocates a new map. Otherwise Unmarshal
-// reuses the existing map, keeping existing entries. Unmarshal then stores key-
-// value pairs from the JSON object into the map. The map's key type must
+// reuses the existing map, keeping existing entries. Unmarshal then stores
+// key-value pairs from the JSON object into the map. The map's key type must
 // either be a string, an integer, or implement encoding.TextUnmarshaler.
 //
 // If a JSON value is not appropriate for a given target type,
@@ -102,6 +109,9 @@ func Unmarshal(data []byte, v interface{}) error {
 // The input can be assumed to be a valid encoding of
 // a JSON value. UnmarshalJSON must copy the JSON data
 // if it wishes to retain the data after returning.
+//
+// By convention, to approximate the behavior of Unmarshal itself,
+// Unmarshalers implement UnmarshalJSON([]byte("null")) as a no-op.
 type Unmarshaler interface {
 	UnmarshalJSON([]byte) error
 }
@@ -112,9 +122,14 @@ type UnmarshalTypeError struct {
 	Value  string       // description of JSON value - "bool", "array", "number -5"
 	Type   reflect.Type // type of Go value it could not be assigned to
 	Offset int64        // error occurred after reading Offset bytes
+	Struct string       // name of the struct type containing the field
+	Field  string       // name of the field holding the Go value
 }
 
 func (e *UnmarshalTypeError) Error() string {
+	if e.Struct != "" || e.Field != "" {
+		return "json: cannot unmarshal " + e.Value + " into Go struct field " + e.Struct + "." + e.Field + " of type " + e.Type.String()
+	}
 	return "json: cannot unmarshal " + e.Value + " into Go value of type " + e.Type.String()
 }
 
@@ -248,10 +263,14 @@ func isValidNumber(s string) bool {
 
 // decodeState represents the state while decoding a JSON value.
 type decodeState struct {
-	data       []byte
-	off        int // read offset in data
-	scan       scanner
-	nextscan   scanner // for calls to nextValue
+	data         []byte
+	off          int // read offset in data
+	scan         scanner
+	nextscan     scanner  // for calls to nextValue
+	errorContext struct { // provides context for type errors
+		Struct string
+		Field  string
+	}
 	savedError error
 	useNumber  bool
 }
@@ -265,22 +284,37 @@ func (d *decodeState) init(data []byte) *decodeState {
 	d.data = data
 	d.off = 0
 	d.savedError = nil
+	d.errorContext.Struct = ""
+	d.errorContext.Field = ""
 	return d
 }
 
 // error aborts the decoding by panicking with err.
 func (d *decodeState) error(err error) {
-	panic(err)
+	panic(d.addErrorContext(err))
 }
 
 // saveError saves the first err it is called with,
 // for reporting at the end of the unmarshal.
 func (d *decodeState) saveError(err error) {
 	if d.savedError == nil {
-		d.savedError = err
+		d.savedError = d.addErrorContext(err)
 	}
 }
 
+// addErrorContext returns a new error enhanced with information from d.errorContext
+func (d *decodeState) addErrorContext(err error) error {
+	if d.errorContext.Struct != "" || d.errorContext.Field != "" {
+		switch err := err.(type) {
+		case *UnmarshalTypeError:
+			err.Struct = d.errorContext.Struct
+			err.Field = d.errorContext.Field
+			return err
+		}
+	}
+	return err
+}
+
 // next cuts off and returns the next full JSON value in d.data[d.off:].
 // The next value is known to be an object or array, not a literal.
 func (d *decodeState) next() []byte {
@@ -434,8 +468,10 @@ func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler,
 			if u, ok := v.Interface().(Unmarshaler); ok {
 				return u, nil, reflect.Value{}
 			}
-			if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
-				return nil, u, reflect.Value{}
+			if !decodingNull {
+				if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
+					return nil, u, reflect.Value{}
+				}
 			}
 		}
 		v = v.Elem()
@@ -457,7 +493,7 @@ func (d *decodeState) array(v reflect.Value) {
 		return
 	}
 	if ut != nil {
-		d.saveError(&UnmarshalTypeError{"array", v.Type(), int64(d.off)})
+		d.saveError(&UnmarshalTypeError{Value: "array", Type: v.Type(), Offset: int64(d.off)})
 		d.off--
 		d.next()
 		return
@@ -476,7 +512,7 @@ func (d *decodeState) array(v reflect.Value) {
 		// Otherwise it's invalid.
 		fallthrough
 	default:
-		d.saveError(&UnmarshalTypeError{"array", v.Type(), int64(d.off)})
+		d.saveError(&UnmarshalTypeError{Value: "array", Type: v.Type(), Offset: int64(d.off)})
 		d.off--
 		d.next()
 		return
@@ -566,7 +602,7 @@ func (d *decodeState) object(v reflect.Value) {
 		return
 	}
 	if ut != nil {
-		d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+		d.saveError(&UnmarshalTypeError{Value: "object", Type: v.Type(), Offset: int64(d.off)})
 		d.off--
 		d.next() // skip over { } in input
 		return
@@ -594,7 +630,7 @@ func (d *decodeState) object(v reflect.Value) {
 			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 		default:
 			if !reflect.PtrTo(t.Key()).Implements(textUnmarshalerType) {
-				d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "object", Type: v.Type(), Offset: int64(d.off)})
 				d.off--
 				d.next() // skip over { } in input
 				return
@@ -604,9 +640,9 @@ func (d *decodeState) object(v reflect.Value) {
 			v.Set(reflect.MakeMap(t))
 		}
 	case reflect.Struct:
-
+		// ok
 	default:
-		d.saveError(&UnmarshalTypeError{"object", v.Type(), int64(d.off)})
+		d.saveError(&UnmarshalTypeError{Value: "object", Type: v.Type(), Offset: int64(d.off)})
 		d.off--
 		d.next() // skip over { } in input
 		return
@@ -671,6 +707,8 @@ func (d *decodeState) object(v reflect.Value) {
 					}
 					subv = subv.Field(i)
 				}
+				d.errorContext.Field = f.name
+				d.errorContext.Struct = v.Type().Name()
 			}
 		}
 
@@ -682,7 +720,6 @@ func (d *decodeState) object(v reflect.Value) {
 			d.error(errPhase)
 		}
 
-		// Read value.
 		if destring {
 			switch qv := d.valueQuoted().(type) {
 			case nil:
@@ -714,7 +751,7 @@ func (d *decodeState) object(v reflect.Value) {
 					s := string(key)
 					n, err := strconv.ParseInt(s, 10, 64)
 					if err != nil || reflect.Zero(kt).OverflowInt(n) {
-						d.saveError(&UnmarshalTypeError{"number " + s, kt, int64(start + 1)})
+						d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
 						return
 					}
 					kv = reflect.ValueOf(n).Convert(kt)
@@ -722,7 +759,7 @@ func (d *decodeState) object(v reflect.Value) {
 					s := string(key)
 					n, err := strconv.ParseUint(s, 10, 64)
 					if err != nil || reflect.Zero(kt).OverflowUint(n) {
-						d.saveError(&UnmarshalTypeError{"number " + s, kt, int64(start + 1)})
+						d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: kt, Offset: int64(start + 1)})
 						return
 					}
 					kv = reflect.ValueOf(n).Convert(kt)
@@ -741,6 +778,9 @@ func (d *decodeState) object(v reflect.Value) {
 		if op != scanObjectValue {
 			d.error(errPhase)
 		}
+
+		d.errorContext.Struct = ""
+		d.errorContext.Field = ""
 	}
 }
 
@@ -767,7 +807,7 @@ func (d *decodeState) convertNumber(s string) (interface{}, error) {
 	}
 	f, err := strconv.ParseFloat(s, 64)
 	if err != nil {
-		return nil, &UnmarshalTypeError{"number " + s, reflect.TypeOf(0.0), int64(d.off)}
+		return nil, &UnmarshalTypeError{Value: "number " + s, Type: reflect.TypeOf(0.0), Offset: int64(d.off)}
 	}
 	return f, nil
 }
@@ -786,8 +826,8 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
 		return
 	}
-	wantptr := item[0] == 'n' // null
-	u, ut, pv := d.indirect(v, wantptr)
+	isNull := item[0] == 'n' // null
+	u, ut, pv := d.indirect(v, isNull)
 	if u != nil {
 		err := u.UnmarshalJSON(item)
 		if err != nil {
@@ -800,7 +840,16 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			if fromQuoted {
 				d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
 			} else {
-				d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+				var val string
+				switch item[0] {
+				case 'n':
+					val = "null"
+				case 't', 'f':
+					val = "bool"
+				default:
+					val = "number"
+				}
+				d.saveError(&UnmarshalTypeError{Value: val, Type: v.Type(), Offset: int64(d.off)})
 			}
 			return
 		}
@@ -823,19 +872,31 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 
 	switch c := item[0]; c {
 	case 'n': // null
+		// The main parser checks that only true and false can reach here,
+		// but if this was a quoted string input, it could be anything.
+		if fromQuoted && string(item) != "null" {
+			d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+			break
+		}
 		switch v.Kind() {
 		case reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
 			v.Set(reflect.Zero(v.Type()))
 			// otherwise, ignore null for primitives/string
 		}
 	case 't', 'f': // true, false
-		value := c == 't'
+		value := item[0] == 't'
+		// The main parser checks that only true and false can reach here,
+		// but if this was a quoted string input, it could be anything.
+		if fromQuoted && string(item) != "true" && string(item) != "false" {
+			d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
+			break
+		}
 		switch v.Kind() {
 		default:
 			if fromQuoted {
 				d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
 			} else {
-				d.saveError(&UnmarshalTypeError{"bool", v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "bool", Type: v.Type(), Offset: int64(d.off)})
 			}
 		case reflect.Bool:
 			v.SetBool(value)
@@ -843,7 +904,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			if v.NumMethod() == 0 {
 				v.Set(reflect.ValueOf(value))
 			} else {
-				d.saveError(&UnmarshalTypeError{"bool", v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "bool", Type: v.Type(), Offset: int64(d.off)})
 			}
 		}
 
@@ -858,10 +919,10 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		}
 		switch v.Kind() {
 		default:
-			d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+			d.saveError(&UnmarshalTypeError{Value: "string", Type: v.Type(), Offset: int64(d.off)})
 		case reflect.Slice:
 			if v.Type().Elem().Kind() != reflect.Uint8 {
-				d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "string", Type: v.Type(), Offset: int64(d.off)})
 				break
 			}
 			b := make([]byte, base64.StdEncoding.DecodedLen(len(s)))
@@ -877,7 +938,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			if v.NumMethod() == 0 {
 				v.Set(reflect.ValueOf(string(s)))
 			} else {
-				d.saveError(&UnmarshalTypeError{"string", v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "string", Type: v.Type(), Offset: int64(d.off)})
 			}
 		}
 
@@ -902,7 +963,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			if fromQuoted {
 				d.error(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
 			} else {
-				d.error(&UnmarshalTypeError{"number", v.Type(), int64(d.off)})
+				d.error(&UnmarshalTypeError{Value: "number", Type: v.Type(), Offset: int64(d.off)})
 			}
 		case reflect.Interface:
 			n, err := d.convertNumber(s)
@@ -911,7 +972,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 				break
 			}
 			if v.NumMethod() != 0 {
-				d.saveError(&UnmarshalTypeError{"number", v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "number", Type: v.Type(), Offset: int64(d.off)})
 				break
 			}
 			v.Set(reflect.ValueOf(n))
@@ -919,7 +980,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 			n, err := strconv.ParseInt(s, 10, 64)
 			if err != nil || v.OverflowInt(n) {
-				d.saveError(&UnmarshalTypeError{"number " + s, v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.off)})
 				break
 			}
 			v.SetInt(n)
@@ -927,7 +988,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 			n, err := strconv.ParseUint(s, 10, 64)
 			if err != nil || v.OverflowUint(n) {
-				d.saveError(&UnmarshalTypeError{"number " + s, v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.off)})
 				break
 			}
 			v.SetUint(n)
@@ -935,7 +996,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		case reflect.Float32, reflect.Float64:
 			n, err := strconv.ParseFloat(s, v.Type().Bits())
 			if err != nil || v.OverflowFloat(n) {
-				d.saveError(&UnmarshalTypeError{"number " + s, v.Type(), int64(d.off)})
+				d.saveError(&UnmarshalTypeError{Value: "number " + s, Type: v.Type(), Offset: int64(d.off)})
 				break
 			}
 			v.SetFloat(n)