From: David Chase <drchase@google.com>
Date: Fri, 14 Apr 2023 18:09:12 +0000 (-0400)
Subject: internal/reflectlite, runtime: move more constants and types into internal/abi
X-Git-Tag: go1.21rc1~600
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=639957eb661c0c99c000bfc2e79bc750b02abd1a;p=gostls13.git

internal/reflectlite, runtime: move more constants and types into internal/abi

Change-Id: If5da1057ead34eb3e4c7f42bbe6ad3d350b97725
Reviewed-on: https://go-review.googlesource.com/c/go/+/484856
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
---

diff --git a/src/internal/reflectlite/all_test.go b/src/internal/reflectlite/all_test.go
index bb3cad470c..820b4aeaf8 100644
--- a/src/internal/reflectlite/all_test.go
+++ b/src/internal/reflectlite/all_test.go
@@ -7,6 +7,7 @@ package reflectlite_test
 import (
 	"encoding/base64"
 	"fmt"
+	"internal/abi"
 	. "internal/reflectlite"
 	"math"
 	"reflect"
@@ -240,37 +241,37 @@ func TestSetValue(t *testing.T) {
 	for i, tt := range valueTests {
 		v := ValueOf(tt.i).Elem()
 		switch v.Kind() {
-		case Int:
+		case abi.Int:
 			v.Set(ValueOf(int(132)))
-		case Int8:
+		case abi.Int8:
 			v.Set(ValueOf(int8(8)))
-		case Int16:
+		case abi.Int16:
 			v.Set(ValueOf(int16(16)))
-		case Int32:
+		case abi.Int32:
 			v.Set(ValueOf(int32(32)))
-		case Int64:
+		case abi.Int64:
 			v.Set(ValueOf(int64(64)))
-		case Uint:
+		case abi.Uint:
 			v.Set(ValueOf(uint(132)))
-		case Uint8:
+		case abi.Uint8:
 			v.Set(ValueOf(uint8(8)))
-		case Uint16:
+		case abi.Uint16:
 			v.Set(ValueOf(uint16(16)))
-		case Uint32:
+		case abi.Uint32:
 			v.Set(ValueOf(uint32(32)))
-		case Uint64:
+		case abi.Uint64:
 			v.Set(ValueOf(uint64(64)))
-		case Float32:
+		case abi.Float32:
 			v.Set(ValueOf(float32(256.25)))
-		case Float64:
+		case abi.Float64:
 			v.Set(ValueOf(512.125))
-		case Complex64:
+		case abi.Complex64:
 			v.Set(ValueOf(complex64(532.125 + 10i)))
-		case Complex128:
+		case abi.Complex128:
 			v.Set(ValueOf(complex128(564.25 + 1i)))
-		case String:
+		case abi.String:
 			v.Set(ValueOf("stringy cheese"))
-		case Bool:
+		case abi.Bool:
 			v.Set(ValueOf(true))
 		}
 		s := valueToString(v)
@@ -946,7 +947,7 @@ func TestInvalid(t *testing.T) {
 		t.Errorf("field: IsValid=%v, Kind=%v, want true, Interface", v.IsValid(), v.Kind())
 	}
 	v = v.Elem()
-	if v.IsValid() != false || v.Kind() != Invalid {
+	if v.IsValid() != false || v.Kind() != abi.Invalid {
 		t.Errorf("field elem: IsValid=%v, Kind=%v, want false, Invalid", v.IsValid(), v.Kind())
 	}
 }
diff --git a/src/internal/reflectlite/reflect_mirror_test.go b/src/internal/reflectlite/reflect_mirror_test.go
index 9b28b13550..dd13ab782a 100644
--- a/src/internal/reflectlite/reflect_mirror_test.go
+++ b/src/internal/reflectlite/reflect_mirror_test.go
@@ -19,7 +19,6 @@ import (
 )
 
 var typeNames = []string{
-	"rtype",
 	"uncommonType",
 	"arrayType",
 	"chanType",
@@ -115,7 +114,7 @@ func TestMirrorWithReflect(t *testing.T) {
 	wg.Wait()
 
 	if len(rl.m) != len(r.m) {
-		t.Fatalf("number of types mismatch, reflect: %d, reflectlite: %d", len(r.m), len(rl.m))
+		t.Fatalf("number of types mismatch, reflect: %d, reflectlite: %d (%+v, %+v)", len(r.m), len(rl.m), r.m, rl.m)
 	}
 
 	for typName := range r.m {
diff --git a/src/internal/reflectlite/type.go b/src/internal/reflectlite/type.go
index 5796b8f168..d562cbe874 100644
--- a/src/internal/reflectlite/type.go
+++ b/src/internal/reflectlite/type.go
@@ -75,45 +75,25 @@ type Type interface {
 
 // A Kind represents the specific kind of type that a Type represents.
 // The zero Kind is not a valid kind.
-type Kind uint
+type Kind = abi.Kind
+
+const Ptr = abi.Pointer
 
 const (
-	Invalid Kind = iota
-	Bool
-	Int
-	Int8
-	Int16
-	Int32
-	Int64
-	Uint
-	Uint8
-	Uint16
-	Uint32
-	Uint64
-	Uintptr
-	Float32
-	Float64
-	Complex64
-	Complex128
-	Array
-	Chan
-	Func
-	Interface
-	Map
-	Pointer
-	Slice
-	String
-	Struct
-	UnsafePointer
+	// Import-and-export these constants as necessary
+	Interface = abi.Interface
+	Slice     = abi.Slice
+	String    = abi.String
+	Struct    = abi.Struct
 )
 
-const Ptr = Pointer
-
 type nameOff = abi.NameOff
 type typeOff = abi.TypeOff
 type textOff = abi.TextOff
 
-type rtype abi.Type
+type rtype struct {
+	abi.Type
+}
 
 // uncommonType is present only for defined types or types with methods
 // (if T is a defined type, the uncommonTypes for T and *T have methods).
@@ -304,50 +284,6 @@ func (n name) pkgPath() string {
  * The compiler does not know about the data structures and methods below.
  */
 
-const (
-	kindDirectIface = 1 << 5
-	kindGCProg      = 1 << 6 // Type.gc points to GC program
-	kindMask        = (1 << 5) - 1
-)
-
-// String returns the name of k.
-func (k Kind) String() string {
-	if int(k) < len(kindNames) {
-		return kindNames[k]
-	}
-	return kindNames[0]
-}
-
-var kindNames = []string{
-	Invalid:       "invalid",
-	Bool:          "bool",
-	Int:           "int",
-	Int8:          "int8",
-	Int16:         "int16",
-	Int32:         "int32",
-	Int64:         "int64",
-	Uint:          "uint",
-	Uint8:         "uint8",
-	Uint16:        "uint16",
-	Uint32:        "uint32",
-	Uint64:        "uint64",
-	Uintptr:       "uintptr",
-	Float32:       "float32",
-	Float64:       "float64",
-	Complex64:     "complex64",
-	Complex128:    "complex128",
-	Array:         "array",
-	Chan:          "chan",
-	Func:          "func",
-	Interface:     "interface",
-	Map:           "map",
-	Ptr:           "ptr",
-	Slice:         "slice",
-	String:        "string",
-	Struct:        "struct",
-	UnsafePointer: "unsafe.Pointer",
-}
-
 // resolveNameOff resolves a name offset from a base pointer.
 // The (*rtype).nameOff method is a convenience wrapper for this function.
 // Implemented in the runtime package.
@@ -367,61 +303,7 @@ func (t *rtype) typeOff(off typeOff) *rtype {
 }
 
 func (t *rtype) uncommon() *uncommonType {
-	if t.TFlag&abi.TFlagUncommon == 0 {
-		return nil
-	}
-	switch t.Kind() {
-	case Struct:
-		return &(*structTypeUncommon)(unsafe.Pointer(t)).u
-	case Ptr:
-		type u struct {
-			ptrType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case Func:
-		type u struct {
-			funcType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case Slice:
-		type u struct {
-			sliceType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case Array:
-		type u struct {
-			arrayType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case Chan:
-		type u struct {
-			chanType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case Map:
-		type u struct {
-			mapType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case Interface:
-		type u struct {
-			interfaceType
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	default:
-		type u struct {
-			rtype
-			u uncommonType
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	}
+	return t.Uncommon()
 }
 
 func (t *rtype) String() string {
@@ -432,10 +314,6 @@ func (t *rtype) String() string {
 	return s
 }
 
-func (t *rtype) Size() uintptr { return t.Size_ }
-
-func (t *rtype) Kind() Kind { return Kind(t.Kind_ & kindMask) }
-
 func (t *rtype) pointers() bool { return t.PtrBytes != 0 }
 
 func (t *rtype) common() *rtype { return t }
@@ -491,28 +369,32 @@ func (t *rtype) Name() string {
 }
 
 func (t *rtype) chanDir() chanDir {
-	if t.Kind() != Chan {
+	if t.Kind() != abi.Chan {
 		panic("reflect: chanDir of non-chan type")
 	}
 	tt := (*chanType)(unsafe.Pointer(t))
 	return chanDir(tt.dir)
 }
 
+func toRType(t *abi.Type) *rtype {
+	return (*rtype)(unsafe.Pointer(t))
+}
+
 func (t *rtype) Elem() Type {
 	switch t.Kind() {
-	case Array:
+	case abi.Array:
 		tt := (*arrayType)(unsafe.Pointer(t))
-		return toType((*rtype)(tt.Elem))
-	case Chan:
+		return toType(toRType(tt.Elem))
+	case abi.Chan:
 		tt := (*chanType)(unsafe.Pointer(t))
 		return toType(tt.elem)
-	case Map:
+	case abi.Map:
 		tt := (*mapType)(unsafe.Pointer(t))
 		return toType(tt.elem)
-	case Ptr:
+	case abi.Pointer:
 		tt := (*ptrType)(unsafe.Pointer(t))
 		return toType(tt.elem)
-	case Slice:
+	case abi.Slice:
 		tt := (*sliceType)(unsafe.Pointer(t))
 		return toType(tt.elem)
 	}
@@ -520,7 +402,7 @@ func (t *rtype) Elem() Type {
 }
 
 func (t *rtype) In(i int) Type {
-	if t.Kind() != Func {
+	if t.Kind() != abi.Func {
 		panic("reflect: In of non-func type")
 	}
 	tt := (*funcType)(unsafe.Pointer(t))
@@ -528,7 +410,7 @@ func (t *rtype) In(i int) Type {
 }
 
 func (t *rtype) Key() Type {
-	if t.Kind() != Map {
+	if t.Kind() != abi.Map {
 		panic("reflect: Key of non-map type")
 	}
 	tt := (*mapType)(unsafe.Pointer(t))
@@ -536,7 +418,7 @@ func (t *rtype) Key() Type {
 }
 
 func (t *rtype) Len() int {
-	if t.Kind() != Array {
+	if t.Kind() != abi.Array {
 		panic("reflect: Len of non-array type")
 	}
 	tt := (*arrayType)(unsafe.Pointer(t))
@@ -544,7 +426,7 @@ func (t *rtype) Len() int {
 }
 
 func (t *rtype) NumField() int {
-	if t.Kind() != Struct {
+	if t.Kind() != abi.Struct {
 		panic("reflect: NumField of non-struct type")
 	}
 	tt := (*structType)(unsafe.Pointer(t))
@@ -552,7 +434,7 @@ func (t *rtype) NumField() int {
 }
 
 func (t *rtype) NumIn() int {
-	if t.Kind() != Func {
+	if t.Kind() != abi.Func {
 		panic("reflect: NumIn of non-func type")
 	}
 	tt := (*funcType)(unsafe.Pointer(t))
@@ -560,7 +442,7 @@ func (t *rtype) NumIn() int {
 }
 
 func (t *rtype) NumOut() int {
-	if t.Kind() != Func {
+	if t.Kind() != abi.Func {
 		panic("reflect: NumOut of non-func type")
 	}
 	tt := (*funcType)(unsafe.Pointer(t))
@@ -568,7 +450,7 @@ func (t *rtype) NumOut() int {
 }
 
 func (t *rtype) Out(i int) Type {
-	if t.Kind() != Func {
+	if t.Kind() != abi.Func {
 		panic("reflect: Out of non-func type")
 	}
 	tt := (*funcType)(unsafe.Pointer(t))
@@ -771,16 +653,16 @@ func haveIdenticalUnderlyingType(T, V *rtype, cmpTags bool) bool {
 
 	// Non-composite types of equal kind have same underlying type
 	// (the predefined instance of the type).
-	if Bool <= kind && kind <= Complex128 || kind == String || kind == UnsafePointer {
+	if abi.Bool <= kind && kind <= abi.Complex128 || kind == abi.String || kind == abi.UnsafePointer {
 		return true
 	}
 
 	// Composite types.
 	switch kind {
-	case Array:
+	case abi.Array:
 		return T.Len() == V.Len() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
 
-	case Chan:
+	case abi.Chan:
 		// Special case:
 		// x is a bidirectional channel value, T is a channel type,
 		// and x's type V and T have identical element types.
@@ -791,7 +673,7 @@ func haveIdenticalUnderlyingType(T, V *rtype, cmpTags bool) bool {
 		// Otherwise continue test for identical underlying type.
 		return V.chanDir() == T.chanDir() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
 
-	case Func:
+	case abi.Func:
 		t := (*funcType)(unsafe.Pointer(T))
 		v := (*funcType)(unsafe.Pointer(V))
 		if t.outCount != v.outCount || t.inCount != v.inCount {
@@ -819,13 +701,13 @@ func haveIdenticalUnderlyingType(T, V *rtype, cmpTags bool) bool {
 		// need a run time conversion.
 		return false
 
-	case Map:
+	case abi.Map:
 		return haveIdenticalType(T.Key(), V.Key(), cmpTags) && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
 
-	case Ptr, Slice:
+	case Ptr, abi.Slice:
 		return haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
 
-	case Struct:
+	case abi.Struct:
 		t := (*structType)(unsafe.Pointer(T))
 		v := (*structType)(unsafe.Pointer(V))
 		if len(t.fields) != len(v.fields) {
@@ -878,5 +760,5 @@ func toType(t *rtype) Type {
 
 // ifaceIndir reports whether t is stored indirectly in an interface value.
 func ifaceIndir(t *rtype) bool {
-	return t.Kind_&kindDirectIface == 0
+	return t.Kind_&abi.KindDirectIface == 0
 }
diff --git a/src/internal/reflectlite/value.go b/src/internal/reflectlite/value.go
index c5b9596617..c14ed7c102 100644
--- a/src/internal/reflectlite/value.go
+++ b/src/internal/reflectlite/value.go
@@ -5,6 +5,7 @@
 package reflectlite
 
 import (
+	"internal/abi"
 	"internal/goarch"
 	"internal/unsafeheader"
 	"runtime"
@@ -89,7 +90,7 @@ func (f flag) ro() flag {
 // pointer returns the underlying pointer represented by v.
 // v.Kind() must be Pointer, Map, Chan, Func, or UnsafePointer
 func (v Value) pointer() unsafe.Pointer {
-	if v.typ.Size_ != goarch.PtrSize || !v.typ.pointers() {
+	if v.typ.Size() != goarch.PtrSize || !v.typ.pointers() {
 		panic("can't call pointer on a non-pointer Value")
 	}
 	if v.flag&flagIndir != 0 {
@@ -198,7 +199,7 @@ func (f flag) mustBeExported() {
 // or it is not addressable.
 func (f flag) mustBeAssignable() {
 	if f == 0 {
-		panic(&ValueError{methodName(), Invalid})
+		panic(&ValueError{methodName(), abi.Invalid})
 	}
 	// Assignable if addressable and not read-only.
 	if f&flagRO != 0 {
@@ -225,7 +226,7 @@ func (v Value) CanSet() bool {
 func (v Value) Elem() Value {
 	k := v.kind()
 	switch k {
-	case Interface:
+	case abi.Interface:
 		var eface any
 		if v.typ.NumMethod() == 0 {
 			eface = *(*any)(v.ptr)
@@ -239,7 +240,7 @@ func (v Value) Elem() Value {
 			x.flag |= v.flag.ro()
 		}
 		return x
-	case Pointer:
+	case abi.Pointer:
 		ptr := v.ptr
 		if v.flag&flagIndir != 0 {
 			ptr = *(*unsafe.Pointer)(ptr)
@@ -262,7 +263,7 @@ func valueInterface(v Value) any {
 		panic(&ValueError{"reflectlite.Value.Interface", 0})
 	}
 
-	if v.kind() == Interface {
+	if v.kind() == abi.Interface {
 		// Special case: return the element inside the interface.
 		// Empty interface has one layout, all interfaces with
 		// methods have a second layout.
@@ -288,7 +289,7 @@ func valueInterface(v Value) any {
 func (v Value) IsNil() bool {
 	k := v.kind()
 	switch k {
-	case Chan, Func, Map, Pointer, UnsafePointer:
+	case abi.Chan, abi.Func, abi.Map, abi.Pointer, abi.UnsafePointer:
 		// if v.flag&flagMethod != 0 {
 		// 	return false
 		// }
@@ -297,7 +298,7 @@ func (v Value) IsNil() bool {
 			ptr = *(*unsafe.Pointer)(ptr)
 		}
 		return ptr == nil
-	case Interface, Slice:
+	case abi.Interface, abi.Slice:
 		// Both interface and slice are nil if first word is 0.
 		// Both are always bigger than a word; assume flagIndir.
 		return *(*unsafe.Pointer)(v.ptr) == nil
@@ -329,17 +330,17 @@ func maplen(unsafe.Pointer) int
 func (v Value) Len() int {
 	k := v.kind()
 	switch k {
-	case Array:
+	case abi.Array:
 		tt := (*arrayType)(unsafe.Pointer(v.typ))
 		return int(tt.Len)
-	case Chan:
+	case abi.Chan:
 		return chanlen(v.pointer())
-	case Map:
+	case abi.Map:
 		return maplen(v.pointer())
-	case Slice:
+	case abi.Slice:
 		// Slice is bigger than a word; assume flagIndir.
 		return (*unsafeheader.Slice)(v.ptr).Len
-	case String:
+	case abi.String:
 		// String is bigger than a word; assume flagIndir.
 		return (*unsafeheader.String)(v.ptr).Len
 	}
@@ -349,7 +350,7 @@ func (v Value) Len() int {
 // NumMethod returns the number of exported methods in the value's method set.
 func (v Value) numMethod() int {
 	if v.typ == nil {
-		panic(&ValueError{"reflectlite.Value.NumMethod", Invalid})
+		panic(&ValueError{"reflectlite.Value.NumMethod", abi.Invalid})
 	}
 	return v.typ.NumMethod()
 }
@@ -361,7 +362,7 @@ func (v Value) Set(x Value) {
 	v.mustBeAssignable()
 	x.mustBeExported() // do not let unexported x leak
 	var target unsafe.Pointer
-	if v.kind() == Interface {
+	if v.kind() == abi.Interface {
 		target = v.ptr
 	}
 	x = x.assignTo("reflectlite.Set", v.typ, target)
@@ -376,7 +377,7 @@ func (v Value) Set(x Value) {
 func (v Value) Type() Type {
 	f := v.flag
 	if f == 0 {
-		panic(&ValueError{"reflectlite.Value.Type", Invalid})
+		panic(&ValueError{"reflectlite.Value.Type", abi.Invalid})
 	}
 	// Method values not supported.
 	return v.typ
@@ -425,11 +426,11 @@ func (v Value) assignTo(context string, dst *rtype, target unsafe.Pointer) Value
 		if target == nil {
 			target = unsafe_New(dst)
 		}
-		if v.Kind() == Interface && v.IsNil() {
+		if v.Kind() == abi.Interface && v.IsNil() {
 			// A nil ReadWriter passed to nil Reader is OK,
 			// but using ifaceE2I below will panic.
 			// Avoid the panic by returning a nil dst (e.g., Reader) explicitly.
-			return Value{dst, nil, flag(Interface)}
+			return Value{dst, nil, flag(abi.Interface)}
 		}
 		x := valueInterface(v)
 		if dst.NumMethod() == 0 {
@@ -437,7 +438,7 @@ func (v Value) assignTo(context string, dst *rtype, target unsafe.Pointer) Value
 		} else {
 			ifaceE2I(dst, x, target)
 		}
-		return Value{dst, target, flagIndir | flag(Interface)}
+		return Value{dst, target, flagIndir | flag(abi.Interface)}
 	}
 
 	// Failed.
diff --git a/src/runtime/alg.go b/src/runtime/alg.go
index 4619abf4f5..e40eb9b47b 100644
--- a/src/runtime/alg.go
+++ b/src/runtime/alg.go
@@ -174,7 +174,7 @@ func typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr {
 	case kindArray:
 		a := (*arraytype)(unsafe.Pointer(t))
 		for i := uintptr(0); i < a.Len; i++ {
-			h = typehash((*_type)(a.Elem), add(p, i*a.Elem.Size_), h)
+			h = typehash(toType(a.Elem), add(p, i*a.Elem.Size_), h)
 		}
 		return h
 	case kindStruct:
diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go
index e92b7e4fed..e2e37284a2 100644
--- a/src/runtime/cgocall.go
+++ b/src/runtime/cgocall.go
@@ -466,11 +466,11 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 			if at.Len != 1 {
 				throw("can't happen")
 			}
-			cgoCheckArg((*_type)(at.Elem), p, at.Elem.Kind_&kindDirectIface == 0, top, msg)
+			cgoCheckArg(toType(at.Elem), p, at.Elem.Kind_&kindDirectIface == 0, top, msg)
 			return
 		}
 		for i := uintptr(0); i < at.Len; i++ {
-			cgoCheckArg((*_type)(at.Elem), p, true, top, msg)
+			cgoCheckArg(toType(at.Elem), p, true, top, msg)
 			p = add(p, at.Elem.Size_)
 		}
 	case kindChan, kindMap:
diff --git a/src/runtime/cgocheck.go b/src/runtime/cgocheck.go
index cc11ef0469..1acf0f9233 100644
--- a/src/runtime/cgocheck.go
+++ b/src/runtime/cgocheck.go
@@ -249,7 +249,7 @@ func cgoCheckUsingType(typ *_type, src unsafe.Pointer, off, size uintptr) {
 		at := (*arraytype)(unsafe.Pointer(typ))
 		for i := uintptr(0); i < at.Len; i++ {
 			if off < at.Elem.Size_ {
-				cgoCheckUsingType((*_type)(at.Elem), src, off, size)
+				cgoCheckUsingType(toType(at.Elem), src, off, size)
 			}
 			src = add(src, at.Elem.Size_)
 			skipped := off
diff --git a/src/runtime/syscall_windows.go b/src/runtime/syscall_windows.go
index 5177f614c8..37f86d0d7f 100644
--- a/src/runtime/syscall_windows.go
+++ b/src/runtime/syscall_windows.go
@@ -186,7 +186,7 @@ func (p *abiDesc) tryRegAssignArg(t *_type, offset uintptr) bool {
 	case kindArray:
 		at := (*arraytype)(unsafe.Pointer(t))
 		if at.Len == 1 {
-			return p.tryRegAssignArg((*_type)(at.Elem), offset)
+			return p.tryRegAssignArg((*_type)(unsafe.Pointer(at.Elem)), offset) // TODO fix when runtime is fully commoned up w/ abi.Type
 		}
 	case kindStruct:
 		st := (*structtype)(unsafe.Pointer(t))
diff --git a/src/runtime/type.go b/src/runtime/type.go
index 85d576379c..bc8ded2821 100644
--- a/src/runtime/type.go
+++ b/src/runtime/type.go
@@ -19,7 +19,9 @@ type textOff = abi.TextOff
 // ../cmd/compile/internal/reflectdata/reflect.go:/^func.dcommontype and
 // ../reflect/type.go:/^type.rtype.
 // ../internal/reflectlite/type.go:/^type.rtype.
-type _type abi.Type
+type _type struct {
+	abi.Type
+}
 
 func (t *_type) string() string {
 	s := t.nameOff(t.Str).name()
@@ -30,65 +32,7 @@ func (t *_type) string() string {
 }
 
 func (t *_type) uncommon() *uncommontype {
-	if t.TFlag&abi.TFlagUncommon == 0 {
-		return nil
-	}
-	switch t.Kind_ & kindMask {
-	case kindStruct:
-		type u struct {
-			structtype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindPtr:
-		type u struct {
-			ptrtype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindFunc:
-		type u struct {
-			functype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindSlice:
-		type u struct {
-			slicetype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindArray:
-		type u struct {
-			arraytype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindChan:
-		type u struct {
-			chantype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindMap:
-		type u struct {
-			maptype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	case kindInterface:
-		type u struct {
-			interfacetype
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	default:
-		type u struct {
-			_type
-			u uncommontype
-		}
-		return &(*u)(unsafe.Pointer(t)).u
-	}
+	return t.Uncommon()
 }
 
 func (t *_type) name() string {
@@ -500,6 +444,10 @@ type _typePair struct {
 	t2 *_type
 }
 
+func toType(t *abi.Type) *_type {
+	return (*_type)(unsafe.Pointer(t))
+}
+
 // typesEqual reports whether two types are equal.
 //
 // Everywhere in the runtime and reflect packages, it is assumed that
@@ -554,7 +502,7 @@ func typesEqual(t, v *_type, seen map[_typePair]struct{}) bool {
 	case kindArray:
 		at := (*arraytype)(unsafe.Pointer(t))
 		av := (*arraytype)(unsafe.Pointer(v))
-		return typesEqual((*_type)(at.Elem), (*_type)(av.Elem), seen) && at.Len == av.Len
+		return typesEqual(toType(at.Elem), toType(av.Elem), seen) && at.Len == av.Len
 	case kindChan:
 		ct := (*chantype)(unsafe.Pointer(t))
 		cv := (*chantype)(unsafe.Pointer(v))