runtime: delete Type and implementations (use reflect instead)

unsafe: delete Typeof, Reflect, Unreflect, New, NewArray

Part of issue 2955 and issue 2968.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5650069

src/cmd/gc/go.h

@@ -764,6 +764,7 @@ EXTERN	Pkg*	gostringpkg;	// fake pkg for Go strings
 EXTERN	Pkg*	runtimepkg;	// package runtime
 EXTERN	Pkg*	stringpkg;	// fake package for C strings
 EXTERN	Pkg*	typepkg;	// fake package for runtime type info
+EXTERN	Pkg*	weaktypepkg;	// weak references to runtime type info
 EXTERN	Pkg*	unsafepkg;	// package unsafe
 EXTERN	Pkg*	phash[128];
 EXTERN	int	tptr;		// either TPTR32 or TPTR64

src/cmd/gc/lex.c

@@ -209,6 +209,10 @@ main(int argc, char *argv[])
 	typepkg = mkpkg(strlit("type"));
 	typepkg->name = "type";
 
+	weaktypepkg = mkpkg(strlit("weak.type"));
+	weaktypepkg->name = "weak.type";
+	weaktypepkg->prefix = "weak.type";  // not weak%2etype
+
 	unsafepkg = mkpkg(strlit("unsafe"));
 	unsafepkg->name = "unsafe";
 

src/cmd/gc/reflect.c

@@ -454,54 +454,17 @@ kinds[] =
 	[TUNSAFEPTR]	= KindUnsafePointer,
 };
 
-static char*
-structnames[] =
-{
-	[TINT]		= "*runtime.IntType",
-	[TUINT]		= "*runtime.UintType",
-	[TINT8]		= "*runtime.IntType",
-	[TUINT8]	= "*runtime.UintType",
-	[TINT16]	= "*runtime.IntType",
-	[TUINT16]	= "*runtime.UintType",
-	[TINT32]	= "*runtime.IntType",
-	[TUINT32]	= "*runtime.UintType",
-	[TINT64]	= "*runtime.IntType",
-	[TUINT64]	= "*runtime.UintType",
-	[TUINTPTR]	= "*runtime.UintType",
-	[TCOMPLEX64]	= "*runtime.ComplexType",
-	[TCOMPLEX128]	= "*runtime.ComplexType",
-	[TFLOAT32]	= "*runtime.FloatType",
-	[TFLOAT64]	= "*runtime.FloatType",
-	[TBOOL]		= "*runtime.BoolType",
-	[TSTRING]	= "*runtime.StringType",
-	[TUNSAFEPTR] =	"*runtime.UnsafePointerType",
-
-	[TPTR32]	= "*runtime.PtrType",
-	[TPTR64]	= "*runtime.PtrType",
-	[TSTRUCT]	= "*runtime.StructType",
-	[TINTER]	= "*runtime.InterfaceType",
-	[TCHAN]		= "*runtime.ChanType",
-	[TMAP]		= "*runtime.MapType",
-	[TARRAY]	= "*runtime.ArrayType",
-	[TFUNC]		= "*runtime.FuncType",
-};
-
 static Sym*
 typestruct(Type *t)
 {
-	char *name;
-	int et;
-
-	et = t->etype;
-	if(et < 0 || et >= nelem(structnames) || (name = structnames[et]) == nil) {
-		fatal("typestruct %lT", t);
-		return nil;	// silence gcc
-	}
-
-	if(isslice(t))
-		name = "*runtime.SliceType";
-
-	return pkglookup(name, typepkg);
+	// We use a weak reference to the reflect type
+	// to avoid requiring package reflect in every binary.
+	// If package reflect is available, the interface{} holding
+	// a runtime type will contain a *reflect.commonType.
+	// Otherwise it will use a nil type word but still be usable
+	// by package runtime (because we always use the memory
+	// after the interface value, not the interface value itself).
+	return pkglookup("*reflect.commonType", weaktypepkg);
 }
 
 int
@@ -580,7 +543,7 @@ dcommontype(Sym *s, int ot, Type *t)
 	ot = dsymptr(s, ot, typestruct(t), 0);
 	ot = dsymptr(s, ot, s, 2*widthptr);
 
-	// ../../pkg/runtime/type.go:/commonType
+	// ../../pkg/reflect/type.go:/^type.commonType
 	// actual type structure
 	//	type commonType struct {
 	//		size uintptr;
@@ -683,16 +646,9 @@ weaktypesym(Type *t)
 {
 	char *p;
 	Sym *s;
-	static Pkg *weak;
-	
-	if(weak == nil) {
-		weak = mkpkg(strlit("weak.type"));
-		weak->name = "weak.type";
-		weak->prefix = "weak.type";  // not weak%2etype
-	}
-	
+
 	p = smprint("%-T", t);
-	s = pkglookup(p, weak);
+	s = pkglookup(p, weaktypepkg);
 	//print("weaktypesym: %s -> %+S\n", p, s);
 	free(p);
 	return s;

src/cmd/ld/dwarf.c

@@ -2317,7 +2317,7 @@ dwarfemitdebugsections(void)
 
 	// Needed by the prettyprinter code for interface inspection.
 	defgotype(lookup_or_diag("type.runtime.commonType"));
-	defgotype(lookup_or_diag("type.runtime.InterfaceType"));
+	defgotype(lookup_or_diag("type.runtime.interfaceType"));
 	defgotype(lookup_or_diag("type.runtime.itab"));
 
 	genasmsym(defdwsymb);

src/pkg/encoding/gob/decode.go

@@ -456,7 +456,7 @@ func allocate(rtyp reflect.Type, p uintptr, indir int) uintptr {
 	}
 	if *(*unsafe.Pointer)(up) == nil {
 		// Allocate object.
-		*(*unsafe.Pointer)(up) = unsafe.New(rtyp)
+		*(*unsafe.Pointer)(up) = unsafe.Pointer(reflect.New(rtyp).Pointer())
 	}
 	return *(*uintptr)(up)
 }
@@ -609,7 +609,7 @@ func (dec *Decoder) decodeMap(mtyp reflect.Type, state *decoderState, p uintptr,
 	// Maps cannot be accessed by moving addresses around the way
 	// that slices etc. can.  We must recover a full reflection value for
 	// the iteration.
-	v := reflect.ValueOf(unsafe.Unreflect(mtyp, unsafe.Pointer(p)))
+	v := reflect.NewAt(mtyp, unsafe.Pointer(p)).Elem()
 	n := int(state.decodeUint())
 	for i := 0; i < n; i++ {
 		key := decodeIntoValue(state, keyOp, keyIndir, allocValue(mtyp.Key()), ovfl)
@@ -662,7 +662,7 @@ func (dec *Decoder) decodeSlice(atyp reflect.Type, state *decoderState, p uintpt
 	// Always write a header at p.
 	hdrp := (*reflect.SliceHeader)(unsafe.Pointer(p))
 	if hdrp.Cap < n {
-		hdrp.Data = uintptr(unsafe.NewArray(atyp.Elem(), n))
+		hdrp.Data = reflect.MakeSlice(atyp, n, n).Pointer()
 		hdrp.Cap = n
 	}
 	hdrp.Len = n
@@ -969,16 +969,16 @@ func (dec *Decoder) gobDecodeOpFor(ut *userTypeInfo) (*decOp, int) {
 		// Caller has gotten us to within one indirection of our value.
 		if i.indir > 0 {
 			if *(*unsafe.Pointer)(p) == nil {
-				*(*unsafe.Pointer)(p) = unsafe.New(ut.base)
+				*(*unsafe.Pointer)(p) = unsafe.Pointer(reflect.New(ut.base).Pointer())
 			}
 		}
 		// Now p is a pointer to the base type.  Do we need to climb out to
 		// get to the receiver type?
 		var v reflect.Value
 		if ut.decIndir == -1 {
-			v = reflect.ValueOf(unsafe.Unreflect(rcvrType, unsafe.Pointer(&p)))
+			v = reflect.NewAt(rcvrType, unsafe.Pointer(&p)).Elem()
 		} else {
-			v = reflect.ValueOf(unsafe.Unreflect(rcvrType, p))
+			v = reflect.NewAt(rcvrType, p).Elem()
 		}
 		state.dec.decodeGobDecoder(state, v)
 	}

src/pkg/encoding/gob/encode.go

@@ -590,7 +590,7 @@ func (enc *Encoder) encOpFor(rt reflect.Type, inProgress map[reflect.Type]*encOp
 				// Maps cannot be accessed by moving addresses around the way
 				// that slices etc. can.  We must recover a full reflection value for
 				// the iteration.
-				v := reflect.ValueOf(unsafe.Unreflect(t, unsafe.Pointer(p)))
+				v := reflect.NewAt(t, unsafe.Pointer(p)).Elem()
 				mv := reflect.Indirect(v)
 				// We send zero-length (but non-nil) maps because the
 				// receiver might want to use the map.  (Maps don't use append.)
@@ -613,7 +613,7 @@ func (enc *Encoder) encOpFor(rt reflect.Type, inProgress map[reflect.Type]*encOp
 			op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
 				// Interfaces transmit the name and contents of the concrete
 				// value they contain.
-				v := reflect.ValueOf(unsafe.Unreflect(t, unsafe.Pointer(p)))
+				v := reflect.NewAt(t, unsafe.Pointer(p)).Elem()
 				iv := reflect.Indirect(v)
 				if !state.sendZero && (!iv.IsValid() || iv.IsNil()) {
 					return
@@ -645,9 +645,9 @@ func (enc *Encoder) gobEncodeOpFor(ut *userTypeInfo) (*encOp, int) {
 		var v reflect.Value
 		if ut.encIndir == -1 {
 			// Need to climb up one level to turn value into pointer.
-			v = reflect.ValueOf(unsafe.Unreflect(rt, unsafe.Pointer(&p)))
+			v = reflect.NewAt(rt, unsafe.Pointer(&p)).Elem()
 		} else {
-			v = reflect.ValueOf(unsafe.Unreflect(rt, p))
+			v = reflect.NewAt(rt, p).Elem()
 		}
 		if !state.sendZero && isZero(v) {
 			return

src/pkg/reflect/type.go

@@ -16,7 +16,6 @@
 package reflect
 
 import (
-	"runtime"
 	"strconv"
 	"sync"
 	"unsafe"
@@ -181,7 +180,7 @@ type Type interface {
 	// It panics if i is not in the range [0, NumOut()).
 	Out(i int) Type
 
-	runtimeType() *runtime.Type
+	runtimeType() *runtimeType
 	common() *commonType
 	uncommon() *uncommonType
 }
@@ -221,128 +220,131 @@ const (
 )
 
 /*
- * Copy of data structures from ../runtime/type.go.
- * For comments, see the ones in that file.
- *
- * These data structures are known to the compiler and the runtime.
- *
- * Putting these types in runtime instead of reflect means that
- * reflect doesn't need to be autolinked into every binary, which
- * simplifies bootstrapping and package dependencies.
- * Unfortunately, it also means that reflect needs its own
- * copy in order to access the private fields.
+ * These data structures are known to the compiler (../../cmd/gc/reflect.c).
+ * A few are known to ../runtime/type.go to convey to debuggers.
  */
 
+// The compiler can only construct empty interface values at
+// compile time; non-empty interface values get created
+// during initialization.  Type is an empty interface
+// so that the compiler can lay out references as data.
+// The underlying type is *reflect.ArrayType and so on.
+type runtimeType interface{}
+
 // commonType is the common implementation of most values.
 // It is embedded in other, public struct types, but always
 // with a unique tag like `reflect:"array"` or `reflect:"ptr"`
 // so that code cannot convert from, say, *arrayType to *ptrType.
-
 type commonType struct {
-	size       uintptr
-	hash       uint32
-	_          uint8
-	align      uint8
-	fieldAlign uint8
-	kind       uint8
-	alg        *uintptr
-	string     *string
-	*uncommonType
-	ptrToThis *runtime.Type
-}
-
+	size          uintptr      // size in bytes
+	hash          uint32       // hash of type; avoids computation in hash tables
+	_             uint8        // unused/padding
+	align         uint8        // alignment of variable with this type
+	fieldAlign    uint8        // alignment of struct field with this type
+	kind          uint8        // enumeration for C
+	alg           *uintptr     // algorithm table (../runtime/runtime.h:/Alg)
+	string        *string      // string form; unnecessary  but undeniably useful
+	*uncommonType              // (relatively) uncommon fields
+	ptrToThis     *runtimeType // pointer to this type, if used in binary or has methods
+}
+
+// Method on non-interface type
 type method struct {
-	name    *string
-	pkgPath *string
-	mtyp    *runtime.Type
-	typ     *runtime.Type
-	ifn     unsafe.Pointer
-	tfn     unsafe.Pointer
-}
-
+	name    *string        // name of method
+	pkgPath *string        // nil for exported Names; otherwise import path
+	mtyp    *runtimeType   // method type (without receiver)
+	typ     *runtimeType   // .(*FuncType) underneath (with receiver)
+	ifn     unsafe.Pointer // fn used in interface call (one-word receiver)
+	tfn     unsafe.Pointer // fn used for normal method call
+}
+
+// uncommonType is present only for types with names or methods
+// (if T is a named type, the uncommonTypes for T and *T have methods).
+// Using a pointer to this struct reduces the overall size required
+// to describe an unnamed type with no methods.
 type uncommonType struct {
-	name    *string
-	pkgPath *string
-	methods []method
+	name    *string  // name of type
+	pkgPath *string  // import path; nil for built-in types like int, string
+	methods []method // methods associated with type
 }
 
 // ChanDir represents a channel type's direction.
 type ChanDir int
 
 const (
-	RecvDir ChanDir = 1 << iota
-	SendDir
-	BothDir = RecvDir | SendDir
+	RecvDir ChanDir             = 1 << iota // <-chan
+	SendDir                                 // chan<-
+	BothDir = RecvDir | SendDir             // chan
 )
 
 // arrayType represents a fixed array type.
 type arrayType struct {
 	commonType `reflect:"array"`
-	elem       *runtime.Type
-	slice      *runtime.Type
+	elem       *runtimeType // array element type
+	slice      *runtimeType // slice type
 	len        uintptr
 }
 
 // chanType represents a channel type.
 type chanType struct {
 	commonType `reflect:"chan"`
-	elem       *runtime.Type
-	dir        uintptr
+	elem       *runtimeType // channel element type
+	dir        uintptr      // channel direction (ChanDir)
 }
 
 // funcType represents a function type.
 type funcType struct {
 	commonType `reflect:"func"`
-	dotdotdot  bool
-	in         []*runtime.Type
-	out        []*runtime.Type
+	dotdotdot  bool           // last input parameter is ...
+	in         []*runtimeType // input parameter types
+	out        []*runtimeType // output parameter types
 }
 
 // imethod represents a method on an interface type
 type imethod struct {
-	name    *string
-	pkgPath *string
-	typ     *runtime.Type
+	name    *string      // name of method
+	pkgPath *string      // nil for exported Names; otherwise import path
+	typ     *runtimeType // .(*FuncType) underneath
 }
 
 // interfaceType represents an interface type.
 type interfaceType struct {
 	commonType `reflect:"interface"`
-	methods    []imethod
+	methods    []imethod // sorted by hash
 }
 
 // mapType represents a map type.
 type mapType struct {
 	commonType `reflect:"map"`
-	key        *runtime.Type
-	elem       *runtime.Type
+	key        *runtimeType // map key type
+	elem       *runtimeType // map element (value) type
 }
 
 // ptrType represents a pointer type.
 type ptrType struct {
 	commonType `reflect:"ptr"`
-	elem       *runtime.Type
+	elem       *runtimeType // pointer element (pointed at) type
 }
 
 // sliceType represents a slice type.
 type sliceType struct {
 	commonType `reflect:"slice"`
-	elem       *runtime.Type
+	elem       *runtimeType // slice element type
 }
 
 // Struct field
 type structField struct {
-	name    *string
-	pkgPath *string
-	typ     *runtime.Type
-	tag     *string
-	offset  uintptr
+	name    *string      // nil for embedded fields
+	pkgPath *string      // nil for exported Names; otherwise import path
+	typ     *runtimeType // type of field
+	tag     *string      // nil if no tag
+	offset  uintptr      // byte offset of field within struct
 }
 
 // structType represents a struct type.
 type structType struct {
 	commonType `reflect:"struct"`
-	fields     []structField
+	fields     []structField // sorted by offset
 }
 
 /*
@@ -909,23 +911,18 @@ func (t *structType) FieldByNameFunc(match func(string) bool) (f StructField, pr
 }
 
 // Convert runtime type to reflect type.
-func toCommonType(p *runtime.Type) *commonType {
+func toCommonType(p *runtimeType) *commonType {
 	if p == nil {
 		return nil
 	}
-	type hdr struct {
-		x interface{}
-		t commonType
-	}
-	x := unsafe.Pointer(p)
-	return &(*hdr)(x).t
+	return (*p).(*commonType)
 }
 
-func toType(p *runtime.Type) Type {
+func toType(p *runtimeType) Type {
 	if p == nil {
 		return nil
 	}
-	return toCommonType(p).toType()
+	return (*p).(*commonType)
 }
 
 // TypeOf returns the reflection Type of the value in the interface{}.
@@ -940,14 +937,14 @@ var ptrMap struct {
 	m map[*commonType]*ptrType
 }
 
-func (t *commonType) runtimeType() *runtime.Type {
-	// The runtime.Type always precedes the commonType in memory.
+func (t *commonType) runtimeType() *runtimeType {
+	// The runtimeType always precedes the commonType in memory.
 	// Adjust pointer to find it.
 	var rt struct {
-		i  runtime.Type
+		i  runtimeType
 		ct commonType
 	}
-	return (*runtime.Type)(unsafe.Pointer(uintptr(unsafe.Pointer(t)) - unsafe.Offsetof(rt.ct)))
+	return (*runtimeType)(unsafe.Pointer(uintptr(unsafe.Pointer(t)) - unsafe.Offsetof(rt.ct)))
 }
 
 // PtrTo returns the pointer type with element t.
@@ -986,16 +983,15 @@ func (ct *commonType) ptrTo() *commonType {
 	}
 
 	var rt struct {
-		i runtime.Type
+		i runtimeType
 		ptrType
 	}
-	rt.i = (*runtime.PtrType)(unsafe.Pointer(&rt.ptrType))
+	rt.i = &rt.commonType
 
 	// initialize p using *byte's ptrType as a prototype.
-	// have to do assignment as ptrType, not runtime.PtrType,
-	// in order to write to unexported fields.
 	p = &rt.ptrType
-	bp := (*ptrType)(unsafe.Pointer(unsafe.Typeof((*byte)(nil)).(*runtime.PtrType)))
+	var ibyte interface{} = (*byte)(nil)
+	bp := (*ptrType)(unsafe.Pointer((**(**runtimeType)(unsafe.Pointer(&ibyte))).(*commonType)))
 	*p = *bp
 
 	s := "*" + *ct.string
@@ -1010,7 +1006,7 @@ func (ct *commonType) ptrTo() *commonType {
 
 	p.uncommonType = nil
 	p.ptrToThis = nil
-	p.elem = (*runtime.Type)(unsafe.Pointer(uintptr(unsafe.Pointer(ct)) - unsafe.Offsetof(rt.ptrType)))
+	p.elem = (*runtimeType)(unsafe.Pointer(uintptr(unsafe.Pointer(ct)) - unsafe.Offsetof(rt.ptrType)))
 
 	ptrMap.m[ct] = p
 	ptrMap.Unlock()

src/pkg/reflect/value.go

@@ -207,7 +207,7 @@ func storeIword(p unsafe.Pointer, w iword, n uintptr) {
 
 // emptyInterface is the header for an interface{} value.
 type emptyInterface struct {
-	typ  *runtime.Type
+	typ  *runtimeType
 	word iword
 }
 
@@ -215,8 +215,8 @@ type emptyInterface struct {
 type nonEmptyInterface struct {
 	// see ../runtime/iface.c:/Itab
 	itab *struct {
-		ityp   *runtime.Type // static interface type
-		typ    *runtime.Type // dynamic concrete type
+		ityp   *runtimeType // static interface type
+		typ    *runtimeType // dynamic concrete type
 		link   unsafe.Pointer
 		bad    int32
 		unused int32
@@ -1606,6 +1606,10 @@ func Copy(dst, src Value) int {
  * constructors
  */
 
+// implemented in package runtime
+func unsafe_New(Type) unsafe.Pointer
+func unsafe_NewArray(Type, int) unsafe.Pointer
+
 // MakeSlice creates a new zero-initialized slice value
 // for the specified slice type, length, and capacity.
 func MakeSlice(typ Type, len, cap int) Value {
@@ -1618,7 +1622,7 @@ func MakeSlice(typ Type, len, cap int) Value {
 
 	// Reinterpret as *SliceHeader to edit.
 	s := (*SliceHeader)(unsafe.Pointer(&x))
-	s.Data = uintptr(unsafe.NewArray(typ.Elem(), cap))
+	s.Data = uintptr(unsafe_NewArray(typ.Elem(), cap))
 	s.Len = len
 	s.Cap = cap
 
@@ -1697,7 +1701,7 @@ func Zero(typ Type) Value {
 	if t.size <= ptrSize {
 		return Value{t, nil, fl}
 	}
-	return Value{t, unsafe.New(typ), fl | flagIndir}
+	return Value{t, unsafe_New(typ), fl | flagIndir}
 }
 
 // New returns a Value representing a pointer to a new zero value
@@ -1706,11 +1710,18 @@ func New(typ Type) Value {
 	if typ == nil {
 		panic("reflect: New(nil)")
 	}
-	ptr := unsafe.New(typ)
+	ptr := unsafe_New(typ)
 	fl := flag(Ptr) << flagKindShift
 	return Value{typ.common().ptrTo(), ptr, fl}
 }
 
+// NewAt returns a Value representing a pointer to a value of the
+// specified type, using p as that pointer.
+func NewAt(typ Type, p unsafe.Pointer) Value {
+	fl := flag(Ptr) << flagKindShift
+	return Value{typ.common().ptrTo(), p, fl}
+}
+
 // assignTo returns a value v that can be assigned directly to typ.
 // It panics if v is not assignable to typ.
 // For a conversion to an interface type, target is a suggested scratch space to use.
@@ -1749,20 +1760,20 @@ func (v Value) assignTo(context string, dst *commonType, target *interface{}) Va
 func chancap(ch iword) int32
 func chanclose(ch iword)
 func chanlen(ch iword) int32
-func chanrecv(t *runtime.Type, ch iword, nb bool) (val iword, selected, received bool)
-func chansend(t *runtime.Type, ch iword, val iword, nb bool) bool
-
-func makechan(typ *runtime.Type, size uint32) (ch iword)
-func makemap(t *runtime.Type) (m iword)
-func mapaccess(t *runtime.Type, m iword, key iword) (val iword, ok bool)
-func mapassign(t *runtime.Type, m iword, key, val iword, ok bool)
-func mapiterinit(t *runtime.Type, m iword) *byte
+func chanrecv(t *runtimeType, ch iword, nb bool) (val iword, selected, received bool)
+func chansend(t *runtimeType, ch iword, val iword, nb bool) bool
+
+func makechan(typ *runtimeType, size uint32) (ch iword)
+func makemap(t *runtimeType) (m iword)
+func mapaccess(t *runtimeType, m iword, key iword) (val iword, ok bool)
+func mapassign(t *runtimeType, m iword, key, val iword, ok bool)
+func mapiterinit(t *runtimeType, m iword) *byte
 func mapiterkey(it *byte) (key iword, ok bool)
 func mapiternext(it *byte)
 func maplen(m iword) int32
 
 func call(fn, arg unsafe.Pointer, n uint32)
-func ifaceE2I(t *runtime.Type, src interface{}, dst unsafe.Pointer)
+func ifaceE2I(t *runtimeType, src interface{}, dst unsafe.Pointer)
 
 // Dummy annotation marking that the value x escapes,
 // for use in cases where the reflect code is so clever that

src/pkg/runtime/error.go

@@ -17,9 +17,6 @@ type Error interface {
 
 // A TypeAssertionError explains a failed type assertion.
 type TypeAssertionError struct {
-	interfaceType   Type // interface had this type
-	concreteType    Type // concrete value had this type
-	assertedType    Type // asserted type
 	interfaceString string
 	concreteString  string
 	assertedString  string
@@ -33,7 +30,7 @@ func (e *TypeAssertionError) Error() string {
 	if inter == "" {
 		inter = "interface"
 	}
-	if e.concreteType == nil {
+	if e.concreteString == "" {
 		return "interface conversion: " + inter + " is nil, not " + e.assertedString
 	}
 	if e.missingMethod == "" {
@@ -44,40 +41,10 @@ func (e *TypeAssertionError) Error() string {
 		": missing method " + e.missingMethod
 }
 
-// Concrete returns the type of the concrete value in the failed type assertion.
-// If the interface value was nil, Concrete returns nil.
-func (e *TypeAssertionError) Concrete() Type {
-	return e.concreteType
-}
-
-// Asserted returns the type incorrectly asserted by the type assertion.
-func (e *TypeAssertionError) Asserted() Type {
-	return e.assertedType
-}
-
-// If the type assertion is to an interface type, MissingMethod returns the
-// name of a method needed to satisfy that interface type but not implemented
-// by Concrete.  If there are multiple such methods,
-// MissingMethod returns one; which one is unspecified.
-// If the type assertion is not to an interface type, MissingMethod returns an empty string.
-func (e *TypeAssertionError) MissingMethod() string {
-	return e.missingMethod
-}
-
 // For calling from C.
-func newTypeAssertionError(pt1, pt2, pt3 *Type, ps1, ps2, ps3 *string, pmeth *string, ret *interface{}) {
-	var t1, t2, t3 Type
+func newTypeAssertionError(ps1, ps2, ps3 *string, pmeth *string, ret *interface{}) {
 	var s1, s2, s3, meth string
 
-	if pt1 != nil {
-		t1 = *pt1
-	}
-	if pt2 != nil {
-		t2 = *pt2
-	}
-	if pt3 != nil {
-		t3 = *pt3
-	}
 	if ps1 != nil {
 		s1 = *ps1
 	}
@@ -90,7 +57,7 @@ func newTypeAssertionError(pt1, pt2, pt3 *Type, ps1, ps2, ps3 *string, pmeth *st
 	if pmeth != nil {
 		meth = *pmeth
 	}
-	*ret = &TypeAssertionError{t1, t2, t3, s1, s2, s3, meth}
+	*ret = &TypeAssertionError{s1, s2, s3, meth}
 }
 
 // An errorString represents a runtime error described by a single string.

src/pkg/runtime/iface.c

@@ -7,14 +7,6 @@
 #include "type.h"
 #include "malloc.h"
 
-enum 
-{
-	// If an empty interface has these bits set in its type
-	// pointer, it was copied from a reflect.Value and is
-	// not a valid empty interface.
-	reflectFlags = 3,
-};
-
 void
 runtime·printiface(Iface i)
 {
@@ -127,7 +119,7 @@ search:
 				if(!canfail) {
 				throw:
 					// didn't find method
-					runtime·newTypeAssertionError(nil, type, inter,
+					runtime·newTypeAssertionError(
 						nil, type->string, inter->string,
 						iname, &err);
 					if(locked)
@@ -243,13 +235,13 @@ assertI2Tret(Type *t, Iface i, byte *ret)
 
 	tab = i.tab;
 	if(tab == nil) {
-		runtime·newTypeAssertionError(nil, nil, t,
+		runtime·newTypeAssertionError(
 			nil, nil, t->string,
 			nil, &err);
 		runtime·panic(err);
 	}
 	if(tab->type != t) {
-		runtime·newTypeAssertionError(tab->inter, tab->type, t,
+		runtime·newTypeAssertionError(
 			tab->inter->string, tab->type->string, t->string,
 			nil, &err);
 		runtime·panic(err);
@@ -289,8 +281,6 @@ runtime·assertE2T(Type *t, Eface e, ...)
 {
 	byte *ret;
 
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	ret = (byte*)(&e+1);
 	assertE2Tret(t, e, ret);
 }
@@ -300,16 +290,14 @@ assertE2Tret(Type *t, Eface e, byte *ret)
 {
 	Eface err;
 
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	if(e.type == nil) {
-		runtime·newTypeAssertionError(nil, nil, t,
+		runtime·newTypeAssertionError(
 			nil, nil, t->string,
 			nil, &err);
 		runtime·panic(err);
 	}
 	if(e.type != t) {
-		runtime·newTypeAssertionError(nil, e.type, t,
+		runtime·newTypeAssertionError(
 			nil, e.type->string, t->string,
 			nil, &err);
 		runtime·panic(err);
@@ -326,8 +314,6 @@ runtime·assertE2T2(Type *t, Eface e, ...)
 	bool *ok;
 	int32 wid;
 
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	ret = (byte*)(&e+1);
 	wid = t->size;
 	ok = (bool*)(ret + wid);
@@ -366,7 +352,7 @@ runtime·assertI2E(InterfaceType* inter, Iface i, Eface ret)
 	tab = i.tab;
 	if(tab == nil) {
 		// explicit conversions require non-nil interface value.
-		runtime·newTypeAssertionError(nil, nil, inter,
+		runtime·newTypeAssertionError(
 			nil, nil, inter->string,
 			nil, &err);
 		runtime·panic(err);
@@ -421,7 +407,7 @@ runtime·ifaceI2I(InterfaceType *inter, Iface i, Iface *ret)
 	tab = i.tab;
 	if(tab == nil) {
 		// explicit conversions require non-nil interface value.
-		runtime·newTypeAssertionError(nil, nil, inter,
+		runtime·newTypeAssertionError(
 			nil, nil, inter->string,
 			nil, &err);
 		runtime·panic(err);
@@ -463,12 +449,10 @@ runtime·ifaceE2I(InterfaceType *inter, Eface e, Iface *ret)
 	Type *t;
 	Eface err;
 
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	t = e.type;
 	if(t == nil) {
 		// explicit conversions require non-nil interface value.
-		runtime·newTypeAssertionError(nil, nil, inter,
+		runtime·newTypeAssertionError(
 			nil, nil, inter->string,
 			nil, &err);
 		runtime·panic(err);
@@ -496,8 +480,6 @@ runtime·assertE2I(InterfaceType* inter, Eface e, Iface ret)
 void
 runtime·assertE2I2(InterfaceType *inter, Eface e, Iface ret, bool ok)
 {
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	if(e.type == nil) {
 		ok = 0;
 		ret.data = nil;
@@ -520,12 +502,10 @@ runtime·assertE2E(InterfaceType* inter, Eface e, Eface ret)
 	Type *t;
 	Eface err;
 
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	t = e.type;
 	if(t == nil) {
 		// explicit conversions require non-nil interface value.
-		runtime·newTypeAssertionError(nil, nil, inter,
+		runtime·newTypeAssertionError(
 			nil, nil, inter->string,
 			nil, &err);
 		runtime·panic(err);
@@ -538,8 +518,6 @@ runtime·assertE2E(InterfaceType* inter, Eface e, Eface ret)
 void
 runtime·assertE2E2(InterfaceType* inter, Eface e, Eface ret, bool ok)
 {
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	USED(inter);
 	ret = e;
 	ok = e.type != nil;
@@ -626,10 +604,6 @@ runtime·ifaceeq_c(Iface i1, Iface i2)
 bool
 runtime·efaceeq_c(Eface e1, Eface e2)
 {
-	if(((uintptr)e1.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
-	if(((uintptr)e2.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	if(e1.type != e2.type)
 		return false;
 	if(e1.type == nil)
@@ -672,8 +646,6 @@ runtime·efacethash(Eface e1, uint32 ret)
 {
 	Type *t;
 
-	if(((uintptr)e1.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	ret = 0;
 	t = e1.type;
 	if(t != nil)
@@ -682,10 +654,8 @@ runtime·efacethash(Eface e1, uint32 ret)
 }
 
 void
-unsafe·Typeof(Eface e, Eface ret)
+reflect·unsafe_Typeof(Eface e, Eface ret)
 {
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
 	if(e.type == nil) {
 		ret.type = nil;
 		ret.data = nil;
@@ -696,73 +666,10 @@ unsafe·Typeof(Eface e, Eface ret)
 }
 
 void
-unsafe·Reflect(Eface e, Eface rettype, void *retaddr)
-{
-	uintptr *p;
-	uintptr x;
-
-	if(((uintptr)e.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
-	if(e.type == nil) {
-		rettype.type = nil;
-		rettype.data = nil;
-		retaddr = 0;
-	} else {
-		rettype = *(Eface*)e.type;
-		if(e.type->size <= sizeof(uintptr)) {
-			// Copy data into x ...
-			x = 0;
-			e.type->alg->copy(e.type->size, &x, &e.data);
-
-			// but then build pointer to x so that Reflect
-			// always returns pointer to data.
-			p = runtime·mal(sizeof(uintptr));
-			*p = x;
-		} else {
-			// Already a pointer, but still make a copy,
-			// to preserve value semantics for interface data.
-			p = runtime·mal(e.type->size);
-			e.type->alg->copy(e.type->size, p, e.data);
-		}
-		retaddr = p;
-	}
-	FLUSH(&rettype);
-	FLUSH(&retaddr);
-}
-
-void
-unsafe·Unreflect(Eface typ, void *addr, Eface e)
-{
-	if(((uintptr)typ.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
-
-	// Reflect library has reinterpreted typ
-	// as its own kind of type structure.
-	// We know that the pointer to the original
-	// type structure sits before the data pointer.
-	e.type = (Type*)((Eface*)typ.data-1);
-
-	// Interface holds either pointer to data
-	// or copy of original data.
-	if(e.type->size <= sizeof(uintptr))
-		e.type->alg->copy(e.type->size, &e.data, addr);
-	else {
-		// Easier: already a pointer to data.
-		// TODO(rsc): Should this make a copy?
-		e.data = addr;
-	}
-
-	FLUSH(&e);
-}
-
-void
-unsafe·New(Eface typ, void *ret)
+reflect·unsafe_New(Eface typ, void *ret)
 {
 	Type *t;
 
-	if(((uintptr)typ.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
-
 	// Reflect library has reinterpreted typ
 	// as its own kind of type structure.
 	// We know that the pointer to the original
@@ -777,14 +684,11 @@ unsafe·New(Eface typ, void *ret)
 }
 
 void
-unsafe·NewArray(Eface typ, uint32 n, void *ret)
+reflect·unsafe_NewArray(Eface typ, uint32 n, void *ret)
 {
 	uint64 size;
 	Type *t;
 
-	if(((uintptr)typ.type&reflectFlags) != 0)
-		runtime·throw("invalid interface value");
-
 	// Reflect library has reinterpreted typ
 	// as its own kind of type structure.
 	// We know that the pointer to the original

src/pkg/runtime/runtime.h

@@ -674,7 +674,7 @@ void	runtime·panicslice(void);
  */
 void	runtime·newError(String, Eface*);
 void	runtime·printany(Eface);
-void	runtime·newTypeAssertionError(Type*, Type*, Type*, String*, String*, String*, String*, Eface*);
+void	runtime·newTypeAssertionError(String*, String*, String*, String*, Eface*);
 void	runtime·newErrorString(String, Eface*);
 void	runtime·fadd64c(uint64, uint64, uint64*);
 void	runtime·fsub64c(uint64, uint64, uint64*);

src/pkg/runtime/type.go

@@ -4,206 +4,51 @@
 
 /*
  * Runtime type representation.
- *
- * The following files know the exact layout of these
- * data structures and must be kept in sync with this file:
- *
- *	../../cmd/gc/reflect.c
- *	../../cmd/ld/dwarf.c decodetype_*
- *	../reflect/type.go
- *	type.h
+ * This file exists only to provide types that 6l can turn into
+ * DWARF information for use by gdb.  Nothing else uses these.
+ * They should match the same types in ../reflect/type.go.
+ * For comments see ../reflect/type.go.
  */
 
 package runtime
 
 import "unsafe"
 
-// The compiler can only construct empty interface values at
-// compile time; non-empty interface values get created
-// during initialization.  Type is an empty interface
-// so that the compiler can lay out references as data.
-type Type interface{}
-
-// All types begin with a few common fields needed for
-// the interface runtime.
 type commonType struct {
-	size          uintptr  // size in bytes
-	hash          uint32   // hash of type; avoids computation in hash tables
-	_             uint8    // unused
-	align         uint8    // alignment of variable with this type
-	fieldAlign    uint8    // alignment of struct field with this type
-	kind          uint8    // enumeration for C
-	alg           *uintptr // algorithm table (../runtime/runtime.h:/Alg)
-	string        *string  // string form; unnecessary  but undeniably useful
-	*uncommonType          // (relatively) uncommon fields
-	ptrToThis     *Type    // pointer to this type, if used in binary or has methods
-}
-
-// Values for commonType.kind.
-const (
-	kindBool = 1 + iota
-	kindInt
-	kindInt8
-	kindInt16
-	kindInt32
-	kindInt64
-	kindUint
-	kindUint8
-	kindUint16
-	kindUint32
-	kindUint64
-	kindUintptr
-	kindFloat32
-	kindFloat64
-	kindComplex64
-	kindComplex128
-	kindArray
-	kindChan
-	kindFunc
-	kindInterface
-	kindMap
-	kindPtr
-	kindSlice
-	kindString
-	kindStruct
-	kindUnsafePointer
-
-	kindNoPointers = 1 << 7 // OR'ed into kind
-)
-
-// Method on non-interface type
-type _method struct { // underscore is to avoid collision with C
-	name    *string        // name of method
-	pkgPath *string        // nil for exported Names; otherwise import path
-	mtyp    *Type          // method type (without receiver)
-	typ     *Type          // .(*FuncType) underneath (with receiver)
-	ifn     unsafe.Pointer // fn used in interface call (one-word receiver)
-	tfn     unsafe.Pointer // fn used for normal method call
+	size       uintptr
+	hash       uint32
+	_          uint8
+	align      uint8
+	fieldAlign uint8
+	kind       uint8
+	alg        *uintptr
+	string     *string
+	*uncommonType
+	ptrToThis *interface{}
+}
+
+type _method struct {
+	name    *string
+	pkgPath *string
+	mtyp    *interface{}
+	typ     *interface{}
+	ifn     unsafe.Pointer
+	tfn     unsafe.Pointer
 }
 
-// uncommonType is present only for types with names or methods
-// (if T is a named type, the uncommonTypes for T and *T have methods).
-// Using a pointer to this struct reduces the overall size required
-// to describe an unnamed type with no methods.
 type uncommonType struct {
-	name    *string   // name of type
-	pkgPath *string   // import path; nil for built-in types like int, string
-	methods []_method // methods associated with type
-}
-
-// BoolType represents a boolean type.
-type BoolType commonType
-
-// FloatType represents a float type.
-type FloatType commonType
-
-// ComplexType represents a complex type.
-type ComplexType commonType
-
-// IntType represents an int type.
-type IntType commonType
-
-// UintType represents a uint type.
-type UintType commonType
-
-// StringType represents a string type.
-type StringType commonType
-
-// UintptrType represents a uintptr type.
-type UintptrType commonType
-
-// UnsafePointerType represents an unsafe.Pointer type.
-type UnsafePointerType commonType
-
-// ArrayType represents a fixed array type.
-type ArrayType struct {
-	commonType
-	elem  *Type // array element type
-	slice *Type // slice type
-	len   uintptr
-}
-
-// SliceType represents a slice type.
-type SliceType struct {
-	commonType
-	elem *Type // slice element type
-}
-
-// ChanDir represents a channel type's direction.
-type ChanDir int
-
-const (
-	RecvDir ChanDir             = 1 << iota // <-chan
-	SendDir                                 // chan<-
-	BothDir = RecvDir | SendDir             // chan
-)
-
-// ChanType represents a channel type.
-type ChanType struct {
-	commonType
-	elem *Type   // channel element type
-	dir  uintptr // channel direction (ChanDir)
-}
-
-// FuncType represents a function type.
-type FuncType struct {
-	commonType
-	dotdotdot bool    // last input parameter is ...
-	in        []*Type // input parameter types
-	out       []*Type // output parameter types
+	name    *string
+	pkgPath *string
+	methods []_method
 }
 
-// Method on interface type
-type _imethod struct { // underscore is to avoid collision with C
-	name    *string // name of method
-	pkgPath *string // nil for exported Names; otherwise import path
-	typ     *Type   // .(*FuncType) underneath
+type _imethod struct {
+	name    *string
+	pkgPath *string
+	typ     *interface{}
 }
 
-// InterfaceType represents an interface type.
-type InterfaceType struct {
+type interfaceType struct {
 	commonType
-	methods []_imethod // sorted by hash
-}
-
-// MapType represents a map type.
-type MapType struct {
-	commonType
-	key  *Type // map key type
-	elem *Type // map element (value) type
-}
-
-// PtrType represents a pointer type.
-type PtrType struct {
-	commonType
-	elem *Type // pointer element (pointed at) type
-}
-
-// Struct field
-type structField struct {
-	name    *string // nil for embedded fields
-	pkgPath *string // nil for exported Names; otherwise import path
-	typ     *Type   // type of field
-	tag     *string // nil if no tag
-	offset  uintptr // byte offset of field within struct
-}
-
-// StructType represents a struct type.
-type StructType struct {
-	commonType
-	fields []structField // sorted by offset
-}
-
-/*
- * Must match iface.c:/Itab and compilers.
- * NOTE: this is the version used by the reflection code, there is another
- * one in iface_defs.go that is closer to the original C version.
- */
-type Itable struct {
-	Itype  *Type // (*tab.inter).(*InterfaceType) is the interface type
-	Type   *Type
-	link   *Itable
-	bad    int32
-	unused int32
-	Fn     [100000]uintptr // bigger than we'll ever see
+	methods []_imethod
 }

src/pkg/unsafe/unsafe.go

@@ -35,27 +35,3 @@ func Offsetof(v ArbitraryType) uintptr
 // that the address of a variable with the type of v will always always be zero mod m.
 // If v is of the form structValue.field, it returns the alignment of field f within struct object obj.
 func Alignof(v ArbitraryType) uintptr
-
-// Typeof returns the type of an interface value, a runtime.Type.
-func Typeof(i interface{}) (typ interface{})
-
-// Reflect unpacks an interface value into its type and the address of a copy of the
-// internal value.
-func Reflect(i interface{}) (typ interface{}, addr Pointer)
-
-// Unreflect inverts Reflect: Given a type and a pointer to a value, it returns an
-// empty interface value with contents the type and the value (not the pointer to
-// the value).  The typ is assumed to contain a pointer to a runtime type; the type
-// information in the interface{} is ignored, so that, for example, both
-// *reflect.structType and *runtime.StructType can be passed for typ.
-func Unreflect(typ interface{}, addr Pointer) (ret interface{})
-
-// New allocates and returns a pointer to memory for a new value of the given type.
-// The typ is assumed to hold a pointer to a runtime type.
-// Callers should use reflect.New or reflect.Zero instead of invoking unsafe.New directly.
-func New(typ interface{}) Pointer
-
-// NewArray allocates and returns a pointer to an array of n elements of the given type.
-// The typ is assumed to hold a pointer to a runtime type.
-// Callers should use reflect.MakeSlice instead of invoking unsafe.NewArray directly.
-func NewArray(typ interface{}, n int) Pointer