[dev.regabi] cmd/compile: split out package reflectdata [generated]

[git-generate]

cd src/cmd/compile/internal/gc
rf '
	ex {
		import "cmd/compile/internal/base"
		thearch.LinkArch.Name -> base.Ctxt.Arch.Name
	}

	# Move out of reflect.go a few functions that should stay.
	mv addsignats obj.go
	mv deferstruct ssa.go

	# Export reflectdata API.
	mv zerosize ZeroSize
	mv hmap MapType
	mv bmap MapBucketType
	mv hiter MapIterType
	mv addsignat NeedRuntimeType
	mv typename TypePtr
	mv typenamesym TypeSym
	mv typesymprefix TypeSymPrefix
	mv itabsym ITabSym
	mv tracksym TrackSym
	mv zeroaddr ZeroAddr
	mv itabname ITabAddr
	mv ifaceMethodOffset InterfaceMethodOffset
	mv peekitabs CompileITabs
	mv addptabs CollectPTabs
	mv algtype AlgType
	mv dtypesym WriteType
	mv dumpbasictypes WriteBasicTypes
	mv dumpimportstrings WriteImportStrings
	mv dumpsignats WriteRuntimeTypes
	mv dumptabs WriteTabs
	mv eqinterface EqInterface
	mv eqstring EqString

	mv GCProg gcProg
	mv EqCanPanic eqCanPanic
	mv IsRegularMemory isRegularMemory
	mv Sig typeSig

	mv hashmem alg.go
	mv CollectPTabs genwrapper ZeroSize reflect.go
	mv alg.go reflect.go cmd/compile/internal/reflectdata
'

Change-Id: Iaae9da9e9fad5f772f5216004823ccff2ea8f139
Reviewed-on: https://go-review.googlesource.com/c/go/+/279475
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

1 files changed, 1836 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/reflectdata/reflect.go b/src/cmd/compile/internal/reflectdata/reflect.go
new file mode 100644
index 0000000000..a5e2fb407a
--- /dev/null
+++ b/src/cmd/compile/internal/reflectdata/reflect.go
@@ -0,0 +1,1836 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package reflectdata
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+	"sync"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/bitvec"
+	"cmd/compile/internal/escape"
+	"cmd/compile/internal/inline"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/liveness"
+	"cmd/compile/internal/objw"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/internal/gcprog"
+	"cmd/internal/obj"
+	"cmd/internal/objabi"
+	"cmd/internal/src"
+)
+
+type itabEntry struct {
+	t, itype *types.Type
+	lsym     *obj.LSym // symbol of the itab itself
+
+	// symbols of each method in
+	// the itab, sorted by byte offset;
+	// filled in by peekitabs
+	entries []*obj.LSym
+}
+
+type ptabEntry struct {
+	s *types.Sym
+	t *types.Type
+}
+
+func CountTabs() (numPTabs, numITabs int) {
+	return len(ptabs), len(itabs)
+}
+
+// runtime interface and reflection data structures
+var (
+	signatmu    sync.Mutex // protects signatset and signatslice
+	signatset   = make(map[*types.Type]struct{})
+	signatslice []*types.Type
+
+	itabs []itabEntry
+	ptabs []ptabEntry
+)
+
+type typeSig struct {
+	name  *types.Sym
+	isym  *types.Sym
+	tsym  *types.Sym
+	type_ *types.Type
+	mtype *types.Type
+}
+
+// Builds a type representing a Bucket structure for
+// the given map type. This type is not visible to users -
+// we include only enough information to generate a correct GC
+// program for it.
+// Make sure this stays in sync with runtime/map.go.
+const (
+	BUCKETSIZE  = 8
+	MAXKEYSIZE  = 128
+	MAXELEMSIZE = 128
+)
+
+func structfieldSize() int { return 3 * types.PtrSize }       // Sizeof(runtime.structfield{})
+func imethodSize() int     { return 4 + 4 }                   // Sizeof(runtime.imethod{})
+func commonSize() int      { return 4*types.PtrSize + 8 + 8 } // Sizeof(runtime._type{})
+
+func uncommonSize(t *types.Type) int { // Sizeof(runtime.uncommontype{})
+	if t.Sym() == nil && len(methods(t)) == 0 {
+		return 0
+	}
+	return 4 + 2 + 2 + 4 + 4
+}
+
+func makefield(name string, t *types.Type) *types.Field {
+	sym := (*types.Pkg)(nil).Lookup(name)
+	return types.NewField(src.NoXPos, sym, t)
+}
+
+// MapBucketType makes the map bucket type given the type of the map.
+func MapBucketType(t *types.Type) *types.Type {
+	if t.MapType().Bucket != nil {
+		return t.MapType().Bucket
+	}
+
+	keytype := t.Key()
+	elemtype := t.Elem()
+	types.CalcSize(keytype)
+	types.CalcSize(elemtype)
+	if keytype.Width > MAXKEYSIZE {
+		keytype = types.NewPtr(keytype)
+	}
+	if elemtype.Width > MAXELEMSIZE {
+		elemtype = types.NewPtr(elemtype)
+	}
+
+	field := make([]*types.Field, 0, 5)
+
+	// The first field is: uint8 topbits[BUCKETSIZE].
+	arr := types.NewArray(types.Types[types.TUINT8], BUCKETSIZE)
+	field = append(field, makefield("topbits", arr))
+
+	arr = types.NewArray(keytype, BUCKETSIZE)
+	arr.SetNoalg(true)
+	keys := makefield("keys", arr)
+	field = append(field, keys)
+
+	arr = types.NewArray(elemtype, BUCKETSIZE)
+	arr.SetNoalg(true)
+	elems := makefield("elems", arr)
+	field = append(field, elems)
+
+	// If keys and elems have no pointers, the map implementation
+	// can keep a list of overflow pointers on the side so that
+	// buckets can be marked as having no pointers.
+	// Arrange for the bucket to have no pointers by changing
+	// the type of the overflow field to uintptr in this case.
+	// See comment on hmap.overflow in runtime/map.go.
+	otyp := types.Types[types.TUNSAFEPTR]
+	if !elemtype.HasPointers() && !keytype.HasPointers() {
+		otyp = types.Types[types.TUINTPTR]
+	}
+	overflow := makefield("overflow", otyp)
+	field = append(field, overflow)
+
+	// link up fields
+	bucket := types.NewStruct(types.NoPkg, field[:])
+	bucket.SetNoalg(true)
+	types.CalcSize(bucket)
+
+	// Check invariants that map code depends on.
+	if !types.IsComparable(t.Key()) {
+		base.Fatalf("unsupported map key type for %v", t)
+	}
+	if BUCKETSIZE < 8 {
+		base.Fatalf("bucket size too small for proper alignment")
+	}
+	if keytype.Align > BUCKETSIZE {
+		base.Fatalf("key align too big for %v", t)
+	}
+	if elemtype.Align > BUCKETSIZE {
+		base.Fatalf("elem align too big for %v", t)
+	}
+	if keytype.Width > MAXKEYSIZE {
+		base.Fatalf("key size to large for %v", t)
+	}
+	if elemtype.Width > MAXELEMSIZE {
+		base.Fatalf("elem size to large for %v", t)
+	}
+	if t.Key().Width > MAXKEYSIZE && !keytype.IsPtr() {
+		base.Fatalf("key indirect incorrect for %v", t)
+	}
+	if t.Elem().Width > MAXELEMSIZE && !elemtype.IsPtr() {
+		base.Fatalf("elem indirect incorrect for %v", t)
+	}
+	if keytype.Width%int64(keytype.Align) != 0 {
+		base.Fatalf("key size not a multiple of key align for %v", t)
+	}
+	if elemtype.Width%int64(elemtype.Align) != 0 {
+		base.Fatalf("elem size not a multiple of elem align for %v", t)
+	}
+	if bucket.Align%keytype.Align != 0 {
+		base.Fatalf("bucket align not multiple of key align %v", t)
+	}
+	if bucket.Align%elemtype.Align != 0 {
+		base.Fatalf("bucket align not multiple of elem align %v", t)
+	}
+	if keys.Offset%int64(keytype.Align) != 0 {
+		base.Fatalf("bad alignment of keys in bmap for %v", t)
+	}
+	if elems.Offset%int64(elemtype.Align) != 0 {
+		base.Fatalf("bad alignment of elems in bmap for %v", t)
+	}
+
+	// Double-check that overflow field is final memory in struct,
+	// with no padding at end.
+	if overflow.Offset != bucket.Width-int64(types.PtrSize) {
+		base.Fatalf("bad offset of overflow in bmap for %v", t)
+	}
+
+	t.MapType().Bucket = bucket
+
+	bucket.StructType().Map = t
+	return bucket
+}
+
+// MapType builds a type representing a Hmap structure for the given map type.
+// Make sure this stays in sync with runtime/map.go.
+func MapType(t *types.Type) *types.Type {
+	if t.MapType().Hmap != nil {
+		return t.MapType().Hmap
+	}
+
+	bmap := MapBucketType(t)
+
+	// build a struct:
+	// type hmap struct {
+	//    count      int
+	//    flags      uint8
+	//    B          uint8
+	//    noverflow  uint16
+	//    hash0      uint32
+	//    buckets    *bmap
+	//    oldbuckets *bmap
+	//    nevacuate  uintptr
+	//    extra      unsafe.Pointer // *mapextra
+	// }
+	// must match runtime/map.go:hmap.
+	fields := []*types.Field{
+		makefield("count", types.Types[types.TINT]),
+		makefield("flags", types.Types[types.TUINT8]),
+		makefield("B", types.Types[types.TUINT8]),
+		makefield("noverflow", types.Types[types.TUINT16]),
+		makefield("hash0", types.Types[types.TUINT32]), // Used in walk.go for OMAKEMAP.
+		makefield("buckets", types.NewPtr(bmap)),       // Used in walk.go for OMAKEMAP.
+		makefield("oldbuckets", types.NewPtr(bmap)),
+		makefield("nevacuate", types.Types[types.TUINTPTR]),
+		makefield("extra", types.Types[types.TUNSAFEPTR]),
+	}
+
+	hmap := types.NewStruct(types.NoPkg, fields)
+	hmap.SetNoalg(true)
+	types.CalcSize(hmap)
+
+	// The size of hmap should be 48 bytes on 64 bit
+	// and 28 bytes on 32 bit platforms.
+	if size := int64(8 + 5*types.PtrSize); hmap.Width != size {
+		base.Fatalf("hmap size not correct: got %d, want %d", hmap.Width, size)
+	}
+
+	t.MapType().Hmap = hmap
+	hmap.StructType().Map = t
+	return hmap
+}
+
+// MapIterType builds a type representing an Hiter structure for the given map type.
+// Make sure this stays in sync with runtime/map.go.
+func MapIterType(t *types.Type) *types.Type {
+	if t.MapType().Hiter != nil {
+		return t.MapType().Hiter
+	}
+
+	hmap := MapType(t)
+	bmap := MapBucketType(t)
+
+	// build a struct:
+	// type hiter struct {
+	//    key         *Key
+	//    elem        *Elem
+	//    t           unsafe.Pointer // *MapType
+	//    h           *hmap
+	//    buckets     *bmap
+	//    bptr        *bmap
+	//    overflow    unsafe.Pointer // *[]*bmap
+	//    oldoverflow unsafe.Pointer // *[]*bmap
+	//    startBucket uintptr
+	//    offset      uint8
+	//    wrapped     bool
+	//    B           uint8
+	//    i           uint8
+	//    bucket      uintptr
+	//    checkBucket uintptr
+	// }
+	// must match runtime/map.go:hiter.
+	fields := []*types.Field{
+		makefield("key", types.NewPtr(t.Key())),   // Used in range.go for TMAP.
+		makefield("elem", types.NewPtr(t.Elem())), // Used in range.go for TMAP.
+		makefield("t", types.Types[types.TUNSAFEPTR]),
+		makefield("h", types.NewPtr(hmap)),
+		makefield("buckets", types.NewPtr(bmap)),
+		makefield("bptr", types.NewPtr(bmap)),
+		makefield("overflow", types.Types[types.TUNSAFEPTR]),
+		makefield("oldoverflow", types.Types[types.TUNSAFEPTR]),
+		makefield("startBucket", types.Types[types.TUINTPTR]),
+		makefield("offset", types.Types[types.TUINT8]),
+		makefield("wrapped", types.Types[types.TBOOL]),
+		makefield("B", types.Types[types.TUINT8]),
+		makefield("i", types.Types[types.TUINT8]),
+		makefield("bucket", types.Types[types.TUINTPTR]),
+		makefield("checkBucket", types.Types[types.TUINTPTR]),
+	}
+
+	// build iterator struct holding the above fields
+	hiter := types.NewStruct(types.NoPkg, fields)
+	hiter.SetNoalg(true)
+	types.CalcSize(hiter)
+	if hiter.Width != int64(12*types.PtrSize) {
+		base.Fatalf("hash_iter size not correct %d %d", hiter.Width, 12*types.PtrSize)
+	}
+	t.MapType().Hiter = hiter
+	hiter.StructType().Map = t
+	return hiter
+}
+
+// methods returns the methods of the non-interface type t, sorted by name.
+// Generates stub functions as needed.
+func methods(t *types.Type) []*typeSig {
+	// method type
+	mt := types.ReceiverBaseType(t)
+
+	if mt == nil {
+		return nil
+	}
+	typecheck.CalcMethods(mt)
+
+	// type stored in interface word
+	it := t
+
+	if !types.IsDirectIface(it) {
+		it = types.NewPtr(t)
+	}
+
+	// make list of methods for t,
+	// generating code if necessary.
+	var ms []*typeSig
+	for _, f := range mt.AllMethods().Slice() {
+		if !f.IsMethod() {
+			base.Fatalf("non-method on %v method %v %v\n", mt, f.Sym, f)
+		}
+		if f.Type.Recv() == nil {
+			base.Fatalf("receiver with no type on %v method %v %v\n", mt, f.Sym, f)
+		}
+		if f.Nointerface() {
+			continue
+		}
+
+		method := f.Sym
+		if method == nil {
+			break
+		}
+
+		// get receiver type for this particular method.
+		// if pointer receiver but non-pointer t and
+		// this is not an embedded pointer inside a struct,
+		// method does not apply.
+		if !types.IsMethodApplicable(t, f) {
+			continue
+		}
+
+		sig := &typeSig{
+			name:  method,
+			isym:  ir.MethodSym(it, method),
+			tsym:  ir.MethodSym(t, method),
+			type_: typecheck.NewMethodType(f.Type, t),
+			mtype: typecheck.NewMethodType(f.Type, nil),
+		}
+		ms = append(ms, sig)
+
+		this := f.Type.Recv().Type
+
+		if !sig.isym.Siggen() {
+			sig.isym.SetSiggen(true)
+			if !types.Identical(this, it) {
+				genwrapper(it, f, sig.isym)
+			}
+		}
+
+		if !sig.tsym.Siggen() {
+			sig.tsym.SetSiggen(true)
+			if !types.Identical(this, t) {
+				genwrapper(t, f, sig.tsym)
+			}
+		}
+	}
+
+	return ms
+}
+
+// imethods returns the methods of the interface type t, sorted by name.
+func imethods(t *types.Type) []*typeSig {
+	var methods []*typeSig
+	for _, f := range t.Fields().Slice() {
+		if f.Type.Kind() != types.TFUNC || f.Sym == nil {
+			continue
+		}
+		if f.Sym.IsBlank() {
+			base.Fatalf("unexpected blank symbol in interface method set")
+		}
+		if n := len(methods); n > 0 {
+			last := methods[n-1]
+			if !last.name.Less(f.Sym) {
+				base.Fatalf("sigcmp vs sortinter %v %v", last.name, f.Sym)
+			}
+		}
+
+		sig := &typeSig{
+			name:  f.Sym,
+			mtype: f.Type,
+			type_: typecheck.NewMethodType(f.Type, nil),
+		}
+		methods = append(methods, sig)
+
+		// NOTE(rsc): Perhaps an oversight that
+		// IfaceType.Method is not in the reflect data.
+		// Generate the method body, so that compiled
+		// code can refer to it.
+		isym := ir.MethodSym(t, f.Sym)
+		if !isym.Siggen() {
+			isym.SetSiggen(true)
+			genwrapper(t, f, isym)
+		}
+	}
+
+	return methods
+}
+
+func dimportpath(p *types.Pkg) {
+	if p.Pathsym != nil {
+		return
+	}
+
+	// If we are compiling the runtime package, there are two runtime packages around
+	// -- localpkg and Runtimepkg. We don't want to produce import path symbols for
+	// both of them, so just produce one for localpkg.
+	if base.Ctxt.Pkgpath == "runtime" && p == ir.Pkgs.Runtime {
+		return
+	}
+
+	str := p.Path
+	if p == types.LocalPkg {
+		// Note: myimportpath != "", or else dgopkgpath won't call dimportpath.
+		str = base.Ctxt.Pkgpath
+	}
+
+	s := base.Ctxt.Lookup("type..importpath." + p.Prefix + ".")
+	ot := dnameData(s, 0, str, "", nil, false)
+	objw.Global(s, int32(ot), obj.DUPOK|obj.RODATA)
+	s.Set(obj.AttrContentAddressable, true)
+	p.Pathsym = s
+}
+
+func dgopkgpath(s *obj.LSym, ot int, pkg *types.Pkg) int {
+	if pkg == nil {
+		return objw.Uintptr(s, ot, 0)
+	}
+
+	if pkg == types.LocalPkg && base.Ctxt.Pkgpath == "" {
+		// If we don't know the full import path of the package being compiled
+		// (i.e. -p was not passed on the compiler command line), emit a reference to
+		// type..importpath.""., which the linker will rewrite using the correct import path.
+		// Every package that imports this one directly defines the symbol.
+		// See also https://groups.google.com/forum/#!topic/golang-dev/myb9s53HxGQ.
+		ns := base.Ctxt.Lookup(`type..importpath."".`)
+		return objw.SymPtr(s, ot, ns, 0)
+	}
+
+	dimportpath(pkg)
+	return objw.SymPtr(s, ot, pkg.Pathsym, 0)
+}
+
+// dgopkgpathOff writes an offset relocation in s at offset ot to the pkg path symbol.
+func dgopkgpathOff(s *obj.LSym, ot int, pkg *types.Pkg) int {
+	if pkg == nil {
+		return objw.Uint32(s, ot, 0)
+	}
+	if pkg == types.LocalPkg && base.Ctxt.Pkgpath == "" {
+		// If we don't know the full import path of the package being compiled
+		// (i.e. -p was not passed on the compiler command line), emit a reference to
+		// type..importpath.""., which the linker will rewrite using the correct import path.
+		// Every package that imports this one directly defines the symbol.
+		// See also https://groups.google.com/forum/#!topic/golang-dev/myb9s53HxGQ.
+		ns := base.Ctxt.Lookup(`type..importpath."".`)
+		return objw.SymPtrOff(s, ot, ns)
+	}
+
+	dimportpath(pkg)
+	return objw.SymPtrOff(s, ot, pkg.Pathsym)
+}
+
+// dnameField dumps a reflect.name for a struct field.
+func dnameField(lsym *obj.LSym, ot int, spkg *types.Pkg, ft *types.Field) int {
+	if !types.IsExported(ft.Sym.Name) && ft.Sym.Pkg != spkg {
+		base.Fatalf("package mismatch for %v", ft.Sym)
+	}
+	nsym := dname(ft.Sym.Name, ft.Note, nil, types.IsExported(ft.Sym.Name))
+	return objw.SymPtr(lsym, ot, nsym, 0)
+}
+
+// dnameData writes the contents of a reflect.name into s at offset ot.
+func dnameData(s *obj.LSym, ot int, name, tag string, pkg *types.Pkg, exported bool) int {
+	if len(name) > 1<<16-1 {
+		base.Fatalf("name too long: %s", name)
+	}
+	if len(tag) > 1<<16-1 {
+		base.Fatalf("tag too long: %s", tag)
+	}
+
+	// Encode name and tag. See reflect/type.go for details.
+	var bits byte
+	l := 1 + 2 + len(name)
+	if exported {
+		bits |= 1 << 0
+	}
+	if len(tag) > 0 {
+		l += 2 + len(tag)
+		bits |= 1 << 1
+	}
+	if pkg != nil {
+		bits |= 1 << 2
+	}
+	b := make([]byte, l)
+	b[0] = bits
+	b[1] = uint8(len(name) >> 8)
+	b[2] = uint8(len(name))
+	copy(b[3:], name)
+	if len(tag) > 0 {
+		tb := b[3+len(name):]
+		tb[0] = uint8(len(tag) >> 8)
+		tb[1] = uint8(len(tag))
+		copy(tb[2:], tag)
+	}
+
+	ot = int(s.WriteBytes(base.Ctxt, int64(ot), b))
+
+	if pkg != nil {
+		ot = dgopkgpathOff(s, ot, pkg)
+	}
+
+	return ot
+}
+
+var dnameCount int
+
+// dname creates a reflect.name for a struct field or method.
+func dname(name, tag string, pkg *types.Pkg, exported bool) *obj.LSym {
+	// Write out data as "type.." to signal two things to the
+	// linker, first that when dynamically linking, the symbol
+	// should be moved to a relro section, and second that the
+	// contents should not be decoded as a type.
+	sname := "type..namedata."
+	if pkg == nil {
+		// In the common case, share data with other packages.
+		if name == "" {
+			if exported {
+				sname += "-noname-exported." + tag
+			} else {
+				sname += "-noname-unexported." + tag
+			}
+		} else {
+			if exported {
+				sname += name + "." + tag
+			} else {
+				sname += name + "-" + tag
+			}
+		}
+	} else {
+		sname = fmt.Sprintf(`%s"".%d`, sname, dnameCount)
+		dnameCount++
+	}
+	s := base.Ctxt.Lookup(sname)
+	if len(s.P) > 0 {
+		return s
+	}
+	ot := dnameData(s, 0, name, tag, pkg, exported)
+	objw.Global(s, int32(ot), obj.DUPOK|obj.RODATA)
+	s.Set(obj.AttrContentAddressable, true)
+	return s
+}
+
+// dextratype dumps the fields of a runtime.uncommontype.
+// dataAdd is the offset in bytes after the header where the
+// backing array of the []method field is written (by dextratypeData).
+func dextratype(lsym *obj.LSym, ot int, t *types.Type, dataAdd int) int {
+	m := methods(t)
+	if t.Sym() == nil && len(m) == 0 {
+		return ot
+	}
+	noff := int(types.Rnd(int64(ot), int64(types.PtrSize)))
+	if noff != ot {
+		base.Fatalf("unexpected alignment in dextratype for %v", t)
+	}
+
+	for _, a := range m {
+		WriteType(a.type_)
+	}
+
+	ot = dgopkgpathOff(lsym, ot, typePkg(t))
+
+	dataAdd += uncommonSize(t)
+	mcount := len(m)
+	if mcount != int(uint16(mcount)) {
+		base.Fatalf("too many methods on %v: %d", t, mcount)
+	}
+	xcount := sort.Search(mcount, func(i int) bool { return !types.IsExported(m[i].name.Name) })
+	if dataAdd != int(uint32(dataAdd)) {
+		base.Fatalf("methods are too far away on %v: %d", t, dataAdd)
+	}
+
+	ot = objw.Uint16(lsym, ot, uint16(mcount))
+	ot = objw.Uint16(lsym, ot, uint16(xcount))
+	ot = objw.Uint32(lsym, ot, uint32(dataAdd))
+	ot = objw.Uint32(lsym, ot, 0)
+	return ot
+}
+
+func typePkg(t *types.Type) *types.Pkg {
+	tsym := t.Sym()
+	if tsym == nil {
+		switch t.Kind() {
+		case types.TARRAY, types.TSLICE, types.TPTR, types.TCHAN:
+			if t.Elem() != nil {
+				tsym = t.Elem().Sym()
+			}
+		}
+	}
+	if tsym != nil && t != types.Types[t.Kind()] && t != types.ErrorType {
+		return tsym.Pkg
+	}
+	return nil
+}
+
+// dextratypeData dumps the backing array for the []method field of
+// runtime.uncommontype.
+func dextratypeData(lsym *obj.LSym, ot int, t *types.Type) int {
+	for _, a := range methods(t) {
+		// ../../../../runtime/type.go:/method
+		exported := types.IsExported(a.name.Name)
+		var pkg *types.Pkg
+		if !exported && a.name.Pkg != typePkg(t) {
+			pkg = a.name.Pkg
+		}
+		nsym := dname(a.name.Name, "", pkg, exported)
+
+		ot = objw.SymPtrOff(lsym, ot, nsym)
+		ot = dmethodptrOff(lsym, ot, WriteType(a.mtype))
+		ot = dmethodptrOff(lsym, ot, a.isym.Linksym())
+		ot = dmethodptrOff(lsym, ot, a.tsym.Linksym())
+	}
+	return ot
+}
+
+func dmethodptrOff(s *obj.LSym, ot int, x *obj.LSym) int {
+	objw.Uint32(s, ot, 0)
+	r := obj.Addrel(s)
+	r.Off = int32(ot)
+	r.Siz = 4
+	r.Sym = x
+	r.Type = objabi.R_METHODOFF
+	return ot + 4
+}
+
+var kinds = []int{
+	types.TINT:        objabi.KindInt,
+	types.TUINT:       objabi.KindUint,
+	types.TINT8:       objabi.KindInt8,
+	types.TUINT8:      objabi.KindUint8,
+	types.TINT16:      objabi.KindInt16,
+	types.TUINT16:     objabi.KindUint16,
+	types.TINT32:      objabi.KindInt32,
+	types.TUINT32:     objabi.KindUint32,
+	types.TINT64:      objabi.KindInt64,
+	types.TUINT64:     objabi.KindUint64,
+	types.TUINTPTR:    objabi.KindUintptr,
+	types.TFLOAT32:    objabi.KindFloat32,
+	types.TFLOAT64:    objabi.KindFloat64,
+	types.TBOOL:       objabi.KindBool,
+	types.TSTRING:     objabi.KindString,
+	types.TPTR:        objabi.KindPtr,
+	types.TSTRUCT:     objabi.KindStruct,
+	types.TINTER:      objabi.KindInterface,
+	types.TCHAN:       objabi.KindChan,
+	types.TMAP:        objabi.KindMap,
+	types.TARRAY:      objabi.KindArray,
+	types.TSLICE:      objabi.KindSlice,
+	types.TFUNC:       objabi.KindFunc,
+	types.TCOMPLEX64:  objabi.KindComplex64,
+	types.TCOMPLEX128: objabi.KindComplex128,
+	types.TUNSAFEPTR:  objabi.KindUnsafePointer,
+}
+
+// tflag is documented in reflect/type.go.
+//
+// tflag values must be kept in sync with copies in:
+//	cmd/compile/internal/gc/reflect.go
+//	cmd/link/internal/ld/decodesym.go
+//	reflect/type.go
+//	runtime/type.go
+const (
+	tflagUncommon      = 1 << 0
+	tflagExtraStar     = 1 << 1
+	tflagNamed         = 1 << 2
+	tflagRegularMemory = 1 << 3
+)
+
+var (
+	memhashvarlen  *obj.LSym
+	memequalvarlen *obj.LSym
+)
+
+// dcommontype dumps the contents of a reflect.rtype (runtime._type).
+func dcommontype(lsym *obj.LSym, t *types.Type) int {
+	types.CalcSize(t)
+	eqfunc := geneq(t)
+
+	sptrWeak := true
+	var sptr *obj.LSym
+	if !t.IsPtr() || t.IsPtrElem() {
+		tptr := types.NewPtr(t)
+		if t.Sym() != nil || methods(tptr) != nil {
+			sptrWeak = false
+		}
+		sptr = WriteType(tptr)
+	}
+
+	gcsym, useGCProg, ptrdata := dgcsym(t)
+
+	// ../../../../reflect/type.go:/^type.rtype
+	// actual type structure
+	//	type rtype struct {
+	//		size          uintptr
+	//		ptrdata       uintptr
+	//		hash          uint32
+	//		tflag         tflag
+	//		align         uint8
+	//		fieldAlign    uint8
+	//		kind          uint8
+	//		equal         func(unsafe.Pointer, unsafe.Pointer) bool
+	//		gcdata        *byte
+	//		str           nameOff
+	//		ptrToThis     typeOff
+	//	}
+	ot := 0
+	ot = objw.Uintptr(lsym, ot, uint64(t.Width))
+	ot = objw.Uintptr(lsym, ot, uint64(ptrdata))
+	ot = objw.Uint32(lsym, ot, types.TypeHash(t))
+
+	var tflag uint8
+	if uncommonSize(t) != 0 {
+		tflag |= tflagUncommon
+	}
+	if t.Sym() != nil && t.Sym().Name != "" {
+		tflag |= tflagNamed
+	}
+	if isRegularMemory(t) {
+		tflag |= tflagRegularMemory
+	}
+
+	exported := false
+	p := t.LongString()
+	// If we're writing out type T,
+	// we are very likely to write out type *T as well.
+	// Use the string "*T"[1:] for "T", so that the two
+	// share storage. This is a cheap way to reduce the
+	// amount of space taken up by reflect strings.
+	if !strings.HasPrefix(p, "*") {
+		p = "*" + p
+		tflag |= tflagExtraStar
+		if t.Sym() != nil {
+			exported = types.IsExported(t.Sym().Name)
+		}
+	} else {
+		if t.Elem() != nil && t.Elem().Sym() != nil {
+			exported = types.IsExported(t.Elem().Sym().Name)
+		}
+	}
+
+	ot = objw.Uint8(lsym, ot, tflag)
+
+	// runtime (and common sense) expects alignment to be a power of two.
+	i := int(t.Align)
+
+	if i == 0 {
+		i = 1
+	}
+	if i&(i-1) != 0 {
+		base.Fatalf("invalid alignment %d for %v", t.Align, t)
+	}
+	ot = objw.Uint8(lsym, ot, t.Align) // align
+	ot = objw.Uint8(lsym, ot, t.Align) // fieldAlign
+
+	i = kinds[t.Kind()]
+	if types.IsDirectIface(t) {
+		i |= objabi.KindDirectIface
+	}
+	if useGCProg {
+		i |= objabi.KindGCProg
+	}
+	ot = objw.Uint8(lsym, ot, uint8(i)) // kind
+	if eqfunc != nil {
+		ot = objw.SymPtr(lsym, ot, eqfunc, 0) // equality function
+	} else {
+		ot = objw.Uintptr(lsym, ot, 0) // type we can't do == with
+	}
+	ot = objw.SymPtr(lsym, ot, gcsym, 0) // gcdata
+
+	nsym := dname(p, "", nil, exported)
+	ot = objw.SymPtrOff(lsym, ot, nsym) // str
+	// ptrToThis
+	if sptr == nil {
+		ot = objw.Uint32(lsym, ot, 0)
+	} else if sptrWeak {
+		ot = objw.SymPtrWeakOff(lsym, ot, sptr)
+	} else {
+		ot = objw.SymPtrOff(lsym, ot, sptr)
+	}
+
+	return ot
+}
+
+// TrackSym returns the symbol for tracking use of field/method f, assumed
+// to be a member of struct/interface type t.
+func TrackSym(t *types.Type, f *types.Field) *types.Sym {
+	return ir.Pkgs.Track.Lookup(t.ShortString() + "." + f.Sym.Name)
+}
+
+func TypeSymPrefix(prefix string, t *types.Type) *types.Sym {
+	p := prefix + "." + t.ShortString()
+	s := types.TypeSymLookup(p)
+
+	// This function is for looking up type-related generated functions
+	// (e.g. eq and hash). Make sure they are indeed generated.
+	signatmu.Lock()
+	NeedRuntimeType(t)
+	signatmu.Unlock()
+
+	//print("algsym: %s -> %+S\n", p, s);
+
+	return s
+}
+
+func TypeSym(t *types.Type) *types.Sym {
+	if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() {
+		base.Fatalf("typenamesym %v", t)
+	}
+	s := types.TypeSym(t)
+	signatmu.Lock()
+	NeedRuntimeType(t)
+	signatmu.Unlock()
+	return s
+}
+
+func TypePtr(t *types.Type) *ir.AddrExpr {
+	s := TypeSym(t)
+	if s.Def == nil {
+		n := ir.NewNameAt(src.NoXPos, s)
+		n.SetType(types.Types[types.TUINT8])
+		n.Class_ = ir.PEXTERN
+		n.SetTypecheck(1)
+		s.Def = n
+	}
+
+	n := typecheck.NodAddr(ir.AsNode(s.Def))
+	n.SetType(types.NewPtr(s.Def.Type()))
+	n.SetTypecheck(1)
+	return n
+}
+
+func ITabAddr(t, itype *types.Type) *ir.AddrExpr {
+	if t == nil || (t.IsPtr() && t.Elem() == nil) || t.IsUntyped() || !itype.IsInterface() || itype.IsEmptyInterface() {
+		base.Fatalf("itabname(%v, %v)", t, itype)
+	}
+	s := ir.Pkgs.Itab.Lookup(t.ShortString() + "," + itype.ShortString())
+	if s.Def == nil {
+		n := typecheck.NewName(s)
+		n.SetType(types.Types[types.TUINT8])
+		n.Class_ = ir.PEXTERN
+		n.SetTypecheck(1)
+		s.Def = n
+		itabs = append(itabs, itabEntry{t: t, itype: itype, lsym: s.Linksym()})
+	}
+
+	n := typecheck.NodAddr(ir.AsNode(s.Def))
+	n.SetType(types.NewPtr(s.Def.Type()))
+	n.SetTypecheck(1)
+	return n
+}
+
+// needkeyupdate reports whether map updates with t as a key
+// need the key to be updated.
+func needkeyupdate(t *types.Type) bool {
+	switch t.Kind() {
+	case types.TBOOL, types.TINT, types.TUINT, types.TINT8, types.TUINT8, types.TINT16, types.TUINT16, types.TINT32, types.TUINT32,
+		types.TINT64, types.TUINT64, types.TUINTPTR, types.TPTR, types.TUNSAFEPTR, types.TCHAN:
+		return false
+
+	case types.TFLOAT32, types.TFLOAT64, types.TCOMPLEX64, types.TCOMPLEX128, // floats and complex can be +0/-0
+		types.TINTER,
+		types.TSTRING: // strings might have smaller backing stores
+		return true
+
+	case types.TARRAY:
+		return needkeyupdate(t.Elem())
+
+	case types.TSTRUCT:
+		for _, t1 := range t.Fields().Slice() {
+			if needkeyupdate(t1.Type) {
+				return true
+			}
+		}
+		return false
+
+	default:
+		base.Fatalf("bad type for map key: %v", t)
+		return true
+	}
+}
+
+// hashMightPanic reports whether the hash of a map key of type t might panic.
+func hashMightPanic(t *types.Type) bool {
+	switch t.Kind() {
+	case types.TINTER:
+		return true
+
+	case types.TARRAY:
+		return hashMightPanic(t.Elem())
+
+	case types.TSTRUCT:
+		for _, t1 := range t.Fields().Slice() {
+			if hashMightPanic(t1.Type) {
+				return true
+			}
+		}
+		return false
+
+	default:
+		return false
+	}
+}
+
+// formalType replaces byte and rune aliases with real types.
+// They've been separate internally to make error messages
+// better, but we have to merge them in the reflect tables.
+func formalType(t *types.Type) *types.Type {
+	if t == types.ByteType || t == types.RuneType {
+		return types.Types[t.Kind()]
+	}
+	return t
+}
+
+func WriteType(t *types.Type) *obj.LSym {
+	t = formalType(t)
+	if t.IsUntyped() {
+		base.Fatalf("dtypesym %v", t)
+	}
+
+	s := types.TypeSym(t)
+	lsym := s.Linksym()
+	if s.Siggen() {
+		return lsym
+	}
+	s.SetSiggen(true)
+
+	// special case (look for runtime below):
+	// when compiling package runtime,
+	// emit the type structures for int, float, etc.
+	tbase := t
+
+	if t.IsPtr() && t.Sym() == nil && t.Elem().Sym() != nil {
+		tbase = t.Elem()
+	}
+	dupok := 0
+	if tbase.Sym() == nil {
+		dupok = obj.DUPOK
+	}
+
+	if base.Ctxt.Pkgpath != "runtime" || (tbase != types.Types[tbase.Kind()] && tbase != types.ByteType && tbase != types.RuneType && tbase != types.ErrorType) { // int, float, etc
+		// named types from other files are defined only by those files
+		if tbase.Sym() != nil && tbase.Sym().Pkg != types.LocalPkg {
+			if i := typecheck.BaseTypeIndex(t); i >= 0 {
+				lsym.Pkg = tbase.Sym().Pkg.Prefix
+				lsym.SymIdx = int32(i)
+				lsym.Set(obj.AttrIndexed, true)
+			}
+			return lsym
+		}
+		// TODO(mdempsky): Investigate whether this can happen.
+		if tbase.Kind() == types.TFORW {
+			return lsym
+		}
+	}
+
+	ot := 0
+	switch t.Kind() {
+	default:
+		ot = dcommontype(lsym, t)
+		ot = dextratype(lsym, ot, t, 0)
+
+	case types.TARRAY:
+		// ../../../../runtime/type.go:/arrayType
+		s1 := WriteType(t.Elem())
+		t2 := types.NewSlice(t.Elem())
+		s2 := WriteType(t2)
+		ot = dcommontype(lsym, t)
+		ot = objw.SymPtr(lsym, ot, s1, 0)
+		ot = objw.SymPtr(lsym, ot, s2, 0)
+		ot = objw.Uintptr(lsym, ot, uint64(t.NumElem()))
+		ot = dextratype(lsym, ot, t, 0)
+
+	case types.TSLICE:
+		// ../../../../runtime/type.go:/sliceType
+		s1 := WriteType(t.Elem())
+		ot = dcommontype(lsym, t)
+		ot = objw.SymPtr(lsym, ot, s1, 0)
+		ot = dextratype(lsym, ot, t, 0)
+
+	case types.TCHAN:
+		// ../../../../runtime/type.go:/chanType
+		s1 := WriteType(t.Elem())
+		ot = dcommontype(lsym, t)
+		ot = objw.SymPtr(lsym, ot, s1, 0)
+		ot = objw.Uintptr(lsym, ot, uint64(t.ChanDir()))
+		ot = dextratype(lsym, ot, t, 0)
+
+	case types.TFUNC:
+		for _, t1 := range t.Recvs().Fields().Slice() {
+			WriteType(t1.Type)
+		}
+		isddd := false
+		for _, t1 := range t.Params().Fields().Slice() {
+			isddd = t1.IsDDD()
+			WriteType(t1.Type)
+		}
+		for _, t1 := range t.Results().Fields().Slice() {
+			WriteType(t1.Type)
+		}
+
+		ot = dcommontype(lsym, t)
+		inCount := t.NumRecvs() + t.NumParams()
+		outCount := t.NumResults()
+		if isddd {
+			outCount |= 1 << 15
+		}
+		ot = objw.Uint16(lsym, ot, uint16(inCount))
+		ot = objw.Uint16(lsym, ot, uint16(outCount))
+		if types.PtrSize == 8 {
+			ot += 4 // align for *rtype
+		}
+
+		dataAdd := (inCount + t.NumResults()) * types.PtrSize
+		ot = dextratype(lsym, ot, t, dataAdd)
+
+		// Array of rtype pointers follows funcType.
+		for _, t1 := range t.Recvs().Fields().Slice() {
+			ot = objw.SymPtr(lsym, ot, WriteType(t1.Type), 0)
+		}
+		for _, t1 := range t.Params().Fields().Slice() {
+			ot = objw.SymPtr(lsym, ot, WriteType(t1.Type), 0)
+		}
+		for _, t1 := range t.Results().Fields().Slice() {
+			ot = objw.SymPtr(lsym, ot, WriteType(t1.Type), 0)
+		}
+
+	case types.TINTER:
+		m := imethods(t)
+		n := len(m)
+		for _, a := range m {
+			WriteType(a.type_)
+		}
+
+		// ../../../../runtime/type.go:/interfaceType
+		ot = dcommontype(lsym, t)
+
+		var tpkg *types.Pkg
+		if t.Sym() != nil && t != types.Types[t.Kind()] && t != types.ErrorType {
+			tpkg = t.Sym().Pkg
+		}
+		ot = dgopkgpath(lsym, ot, tpkg)
+
+		ot = objw.SymPtr(lsym, ot, lsym, ot+3*types.PtrSize+uncommonSize(t))
+		ot = objw.Uintptr(lsym, ot, uint64(n))
+		ot = objw.Uintptr(lsym, ot, uint64(n))
+		dataAdd := imethodSize() * n
+		ot = dextratype(lsym, ot, t, dataAdd)
+
+		for _, a := range m {
+			// ../../../../runtime/type.go:/imethod
+			exported := types.IsExported(a.name.Name)
+			var pkg *types.Pkg
+			if !exported && a.name.Pkg != tpkg {
+				pkg = a.name.Pkg
+			}
+			nsym := dname(a.name.Name, "", pkg, exported)
+
+			ot = objw.SymPtrOff(lsym, ot, nsym)
+			ot = objw.SymPtrOff(lsym, ot, WriteType(a.type_))
+		}
+
+	// ../../../../runtime/type.go:/mapType
+	case types.TMAP:
+		s1 := WriteType(t.Key())
+		s2 := WriteType(t.Elem())
+		s3 := WriteType(MapBucketType(t))
+		hasher := genhash(t.Key())
+
+		ot = dcommontype(lsym, t)
+		ot = objw.SymPtr(lsym, ot, s1, 0)
+		ot = objw.SymPtr(lsym, ot, s2, 0)
+		ot = objw.SymPtr(lsym, ot, s3, 0)
+		ot = objw.SymPtr(lsym, ot, hasher, 0)
+		var flags uint32
+		// Note: flags must match maptype accessors in ../../../../runtime/type.go
+		// and maptype builder in ../../../../reflect/type.go:MapOf.
+		if t.Key().Width > MAXKEYSIZE {
+			ot = objw.Uint8(lsym, ot, uint8(types.PtrSize))
+			flags |= 1 // indirect key
+		} else {
+			ot = objw.Uint8(lsym, ot, uint8(t.Key().Width))
+		}
+
+		if t.Elem().Width > MAXELEMSIZE {
+			ot = objw.Uint8(lsym, ot, uint8(types.PtrSize))
+			flags |= 2 // indirect value
+		} else {
+			ot = objw.Uint8(lsym, ot, uint8(t.Elem().Width))
+		}
+		ot = objw.Uint16(lsym, ot, uint16(MapBucketType(t).Width))
+		if types.IsReflexive(t.Key()) {
+			flags |= 4 // reflexive key
+		}
+		if needkeyupdate(t.Key()) {
+			flags |= 8 // need key update
+		}
+		if hashMightPanic(t.Key()) {
+			flags |= 16 // hash might panic
+		}
+		ot = objw.Uint32(lsym, ot, flags)
+		ot = dextratype(lsym, ot, t, 0)
+
+	case types.TPTR:
+		if t.Elem().Kind() == types.TANY {
+			// ../../../../runtime/type.go:/UnsafePointerType
+			ot = dcommontype(lsym, t)
+			ot = dextratype(lsym, ot, t, 0)
+
+			break
+		}
+
+		// ../../../../runtime/type.go:/ptrType
+		s1 := WriteType(t.Elem())
+
+		ot = dcommontype(lsym, t)
+		ot = objw.SymPtr(lsym, ot, s1, 0)
+		ot = dextratype(lsym, ot, t, 0)
+
+	// ../../../../runtime/type.go:/structType
+	// for security, only the exported fields.
+	case types.TSTRUCT:
+		fields := t.Fields().Slice()
+		for _, t1 := range fields {
+			WriteType(t1.Type)
+		}
+
+		// All non-exported struct field names within a struct
+		// type must originate from a single package. By
+		// identifying and recording that package within the
+		// struct type descriptor, we can omit that
+		// information from the field descriptors.
+		var spkg *types.Pkg
+		for _, f := range fields {
+			if !types.IsExported(f.Sym.Name) {
+				spkg = f.Sym.Pkg
+				break
+			}
+		}
+
+		ot = dcommontype(lsym, t)
+		ot = dgopkgpath(lsym, ot, spkg)
+		ot = objw.SymPtr(lsym, ot, lsym, ot+3*types.PtrSize+uncommonSize(t))
+		ot = objw.Uintptr(lsym, ot, uint64(len(fields)))
+		ot = objw.Uintptr(lsym, ot, uint64(len(fields)))
+
+		dataAdd := len(fields) * structfieldSize()
+		ot = dextratype(lsym, ot, t, dataAdd)
+
+		for _, f := range fields {
+			// ../../../../runtime/type.go:/structField
+			ot = dnameField(lsym, ot, spkg, f)
+			ot = objw.SymPtr(lsym, ot, WriteType(f.Type), 0)
+			offsetAnon := uint64(f.Offset) << 1
+			if offsetAnon>>1 != uint64(f.Offset) {
+				base.Fatalf("%v: bad field offset for %s", t, f.Sym.Name)
+			}
+			if f.Embedded != 0 {
+				offsetAnon |= 1
+			}
+			ot = objw.Uintptr(lsym, ot, offsetAnon)
+		}
+	}
+
+	ot = dextratypeData(lsym, ot, t)
+	objw.Global(lsym, int32(ot), int16(dupok|obj.RODATA))
+
+	// The linker will leave a table of all the typelinks for
+	// types in the binary, so the runtime can find them.
+	//
+	// When buildmode=shared, all types are in typelinks so the
+	// runtime can deduplicate type pointers.
+	keep := base.Ctxt.Flag_dynlink
+	if !keep && t.Sym() == nil {
+		// For an unnamed type, we only need the link if the type can
+		// be created at run time by reflect.PtrTo and similar
+		// functions. If the type exists in the program, those
+		// functions must return the existing type structure rather
+		// than creating a new one.
+		switch t.Kind() {
+		case types.TPTR, types.TARRAY, types.TCHAN, types.TFUNC, types.TMAP, types.TSLICE, types.TSTRUCT:
+			keep = true
+		}
+	}
+	// Do not put Noalg types in typelinks.  See issue #22605.
+	if types.TypeHasNoAlg(t) {
+		keep = false
+	}
+	lsym.Set(obj.AttrMakeTypelink, keep)
+
+	return lsym
+}
+
+// InterfaceMethodOffset returns the offset of the i-th method in the interface
+// type descriptor, ityp.
+func InterfaceMethodOffset(ityp *types.Type, i int64) int64 {
+	// interface type descriptor layout is struct {
+	//   _type        // commonSize
+	//   pkgpath      // 1 word
+	//   []imethod    // 3 words (pointing to [...]imethod below)
+	//   uncommontype // uncommonSize
+	//   [...]imethod
+	// }
+	// The size of imethod is 8.
+	return int64(commonSize()+4*types.PtrSize+uncommonSize(ityp)) + i*8
+}
+
+// for each itabEntry, gather the methods on
+// the concrete type that implement the interface
+func CompileITabs() {
+	for i := range itabs {
+		tab := &itabs[i]
+		methods := genfun(tab.t, tab.itype)
+		if len(methods) == 0 {
+			continue
+		}
+		tab.entries = methods
+	}
+}
+
+// for the given concrete type and interface
+// type, return the (sorted) set of methods
+// on the concrete type that implement the interface
+func genfun(t, it *types.Type) []*obj.LSym {
+	if t == nil || it == nil {
+		return nil
+	}
+	sigs := imethods(it)
+	methods := methods(t)
+	out := make([]*obj.LSym, 0, len(sigs))
+	// TODO(mdempsky): Short circuit before calling methods(t)?
+	// See discussion on CL 105039.
+	if len(sigs) == 0 {
+		return nil
+	}
+
+	// both sigs and methods are sorted by name,
+	// so we can find the intersect in a single pass
+	for _, m := range methods {
+		if m.name == sigs[0].name {
+			out = append(out, m.isym.Linksym())
+			sigs = sigs[1:]
+			if len(sigs) == 0 {
+				break
+			}
+		}
+	}
+
+	if len(sigs) != 0 {
+		base.Fatalf("incomplete itab")
+	}
+
+	return out
+}
+
+// ITabSym uses the information gathered in
+// peekitabs to de-virtualize interface methods.
+// Since this is called by the SSA backend, it shouldn't
+// generate additional Nodes, Syms, etc.
+func ITabSym(it *obj.LSym, offset int64) *obj.LSym {
+	var syms []*obj.LSym
+	if it == nil {
+		return nil
+	}
+
+	for i := range itabs {
+		e := &itabs[i]
+		if e.lsym == it {
+			syms = e.entries
+			break
+		}
+	}
+	if syms == nil {
+		return nil
+	}
+
+	// keep this arithmetic in sync with *itab layout
+	methodnum := int((offset - 2*int64(types.PtrSize) - 8) / int64(types.PtrSize))
+	if methodnum >= len(syms) {
+		return nil
+	}
+	return syms[methodnum]
+}
+
+// NeedRuntimeType ensures that a runtime type descriptor is emitted for t.
+func NeedRuntimeType(t *types.Type) {
+	if _, ok := signatset[t]; !ok {
+		signatset[t] = struct{}{}
+		signatslice = append(signatslice, t)
+	}
+}
+
+func WriteRuntimeTypes() {
+	// Process signatset. Use a loop, as dtypesym adds
+	// entries to signatset while it is being processed.
+	signats := make([]typeAndStr, len(signatslice))
+	for len(signatslice) > 0 {
+		signats = signats[:0]
+		// Transfer entries to a slice and sort, for reproducible builds.
+		for _, t := range signatslice {
+			signats = append(signats, typeAndStr{t: t, short: types.TypeSymName(t), regular: t.String()})
+			delete(signatset, t)
+		}
+		signatslice = signatslice[:0]
+		sort.Sort(typesByString(signats))
+		for _, ts := range signats {
+			t := ts.t
+			WriteType(t)
+			if t.Sym() != nil {
+				WriteType(types.NewPtr(t))
+			}
+		}
+	}
+}
+
+func WriteTabs() {
+	// process itabs
+	for _, i := range itabs {
+		// dump empty itab symbol into i.sym
+		// type itab struct {
+		//   inter  *interfacetype
+		//   _type  *_type
+		//   hash   uint32
+		//   _      [4]byte
+		//   fun    [1]uintptr // variable sized
+		// }
+		o := objw.SymPtr(i.lsym, 0, WriteType(i.itype), 0)
+		o = objw.SymPtr(i.lsym, o, WriteType(i.t), 0)
+		o = objw.Uint32(i.lsym, o, types.TypeHash(i.t)) // copy of type hash
+		o += 4                                          // skip unused field
+		for _, fn := range genfun(i.t, i.itype) {
+			o = objw.SymPtr(i.lsym, o, fn, 0) // method pointer for each method
+		}
+		// Nothing writes static itabs, so they are read only.
+		objw.Global(i.lsym, int32(o), int16(obj.DUPOK|obj.RODATA))
+		i.lsym.Set(obj.AttrContentAddressable, true)
+	}
+
+	// process ptabs
+	if types.LocalPkg.Name == "main" && len(ptabs) > 0 {
+		ot := 0
+		s := base.Ctxt.Lookup("go.plugin.tabs")
+		for _, p := range ptabs {
+			// Dump ptab symbol into go.pluginsym package.
+			//
+			// type ptab struct {
+			//	name nameOff
+			//	typ  typeOff // pointer to symbol
+			// }
+			nsym := dname(p.s.Name, "", nil, true)
+			tsym := WriteType(p.t)
+			ot = objw.SymPtrOff(s, ot, nsym)
+			ot = objw.SymPtrOff(s, ot, tsym)
+			// Plugin exports symbols as interfaces. Mark their types
+			// as UsedInIface.
+			tsym.Set(obj.AttrUsedInIface, true)
+		}
+		objw.Global(s, int32(ot), int16(obj.RODATA))
+
+		ot = 0
+		s = base.Ctxt.Lookup("go.plugin.exports")
+		for _, p := range ptabs {
+			ot = objw.SymPtr(s, ot, p.s.Linksym(), 0)
+		}
+		objw.Global(s, int32(ot), int16(obj.RODATA))
+	}
+}
+
+func WriteImportStrings() {
+	// generate import strings for imported packages
+	for _, p := range types.ImportedPkgList() {
+		dimportpath(p)
+	}
+}
+
+func WriteBasicTypes() {
+	// do basic types if compiling package runtime.
+	// they have to be in at least one package,
+	// and runtime is always loaded implicitly,
+	// so this is as good as any.
+	// another possible choice would be package main,
+	// but using runtime means fewer copies in object files.
+	if base.Ctxt.Pkgpath == "runtime" {
+		for i := types.Kind(1); i <= types.TBOOL; i++ {
+			WriteType(types.NewPtr(types.Types[i]))
+		}
+		WriteType(types.NewPtr(types.Types[types.TSTRING]))
+		WriteType(types.NewPtr(types.Types[types.TUNSAFEPTR]))
+
+		// emit type structs for error and func(error) string.
+		// The latter is the type of an auto-generated wrapper.
+		WriteType(types.NewPtr(types.ErrorType))
+
+		WriteType(typecheck.NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.ErrorType)}, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.Types[types.TSTRING])}))
+
+		// add paths for runtime and main, which 6l imports implicitly.
+		dimportpath(ir.Pkgs.Runtime)
+
+		if base.Flag.Race {
+			dimportpath(ir.Pkgs.Race)
+		}
+		if base.Flag.MSan {
+			dimportpath(ir.Pkgs.Msan)
+		}
+		dimportpath(types.NewPkg("main", ""))
+	}
+}
+
+type typeAndStr struct {
+	t       *types.Type
+	short   string
+	regular string
+}
+
+type typesByString []typeAndStr
+
+func (a typesByString) Len() int { return len(a) }
+func (a typesByString) Less(i, j int) bool {
+	if a[i].short != a[j].short {
+		return a[i].short < a[j].short
+	}
+	// When the only difference between the types is whether
+	// they refer to byte or uint8, such as **byte vs **uint8,
+	// the types' ShortStrings can be identical.
+	// To preserve deterministic sort ordering, sort these by String().
+	if a[i].regular != a[j].regular {
+		return a[i].regular < a[j].regular
+	}
+	// Identical anonymous interfaces defined in different locations
+	// will be equal for the above checks, but different in DWARF output.
+	// Sort by source position to ensure deterministic order.
+	// See issues 27013 and 30202.
+	if a[i].t.Kind() == types.TINTER && a[i].t.Methods().Len() > 0 {
+		return a[i].t.Methods().Index(0).Pos.Before(a[j].t.Methods().Index(0).Pos)
+	}
+	return false
+}
+func (a typesByString) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+
+// maxPtrmaskBytes is the maximum length of a GC ptrmask bitmap,
+// which holds 1-bit entries describing where pointers are in a given type.
+// Above this length, the GC information is recorded as a GC program,
+// which can express repetition compactly. In either form, the
+// information is used by the runtime to initialize the heap bitmap,
+// and for large types (like 128 or more words), they are roughly the
+// same speed. GC programs are never much larger and often more
+// compact. (If large arrays are involved, they can be arbitrarily
+// more compact.)
+//
+// The cutoff must be large enough that any allocation large enough to
+// use a GC program is large enough that it does not share heap bitmap
+// bytes with any other objects, allowing the GC program execution to
+// assume an aligned start and not use atomic operations. In the current
+// runtime, this means all malloc size classes larger than the cutoff must
+// be multiples of four words. On 32-bit systems that's 16 bytes, and
+// all size classes >= 16 bytes are 16-byte aligned, so no real constraint.
+// On 64-bit systems, that's 32 bytes, and 32-byte alignment is guaranteed
+// for size classes >= 256 bytes. On a 64-bit system, 256 bytes allocated
+// is 32 pointers, the bits for which fit in 4 bytes. So maxPtrmaskBytes
+// must be >= 4.
+//
+// We used to use 16 because the GC programs do have some constant overhead
+// to get started, and processing 128 pointers seems to be enough to
+// amortize that overhead well.
+//
+// To make sure that the runtime's chansend can call typeBitsBulkBarrier,
+// we raised the limit to 2048, so that even 32-bit systems are guaranteed to
+// use bitmaps for objects up to 64 kB in size.
+//
+// Also known to reflect/type.go.
+//
+const maxPtrmaskBytes = 2048
+
+// dgcsym emits and returns a data symbol containing GC information for type t,
+// along with a boolean reporting whether the UseGCProg bit should be set in
+// the type kind, and the ptrdata field to record in the reflect type information.
+func dgcsym(t *types.Type) (lsym *obj.LSym, useGCProg bool, ptrdata int64) {
+	ptrdata = types.PtrDataSize(t)
+	if ptrdata/int64(types.PtrSize) <= maxPtrmaskBytes*8 {
+		lsym = dgcptrmask(t)
+		return
+	}
+
+	useGCProg = true
+	lsym, ptrdata = dgcprog(t)
+	return
+}
+
+// dgcptrmask emits and returns the symbol containing a pointer mask for type t.
+func dgcptrmask(t *types.Type) *obj.LSym {
+	ptrmask := make([]byte, (types.PtrDataSize(t)/int64(types.PtrSize)+7)/8)
+	fillptrmask(t, ptrmask)
+	p := fmt.Sprintf("gcbits.%x", ptrmask)
+
+	sym := ir.Pkgs.Runtime.Lookup(p)
+	lsym := sym.Linksym()
+	if !sym.Uniq() {
+		sym.SetUniq(true)
+		for i, x := range ptrmask {
+			objw.Uint8(lsym, i, x)
+		}
+		objw.Global(lsym, int32(len(ptrmask)), obj.DUPOK|obj.RODATA|obj.LOCAL)
+		lsym.Set(obj.AttrContentAddressable, true)
+	}
+	return lsym
+}
+
+// fillptrmask fills in ptrmask with 1s corresponding to the
+// word offsets in t that hold pointers.
+// ptrmask is assumed to fit at least typeptrdata(t)/Widthptr bits.
+func fillptrmask(t *types.Type, ptrmask []byte) {
+	for i := range ptrmask {
+		ptrmask[i] = 0
+	}
+	if !t.HasPointers() {
+		return
+	}
+
+	vec := bitvec.New(8 * int32(len(ptrmask)))
+	liveness.SetTypeBits(t, 0, vec)
+
+	nptr := types.PtrDataSize(t) / int64(types.PtrSize)
+	for i := int64(0); i < nptr; i++ {
+		if vec.Get(int32(i)) {
+			ptrmask[i/8] |= 1 << (uint(i) % 8)
+		}
+	}
+}
+
+// dgcprog emits and returns the symbol containing a GC program for type t
+// along with the size of the data described by the program (in the range [typeptrdata(t), t.Width]).
+// In practice, the size is typeptrdata(t) except for non-trivial arrays.
+// For non-trivial arrays, the program describes the full t.Width size.
+func dgcprog(t *types.Type) (*obj.LSym, int64) {
+	types.CalcSize(t)
+	if t.Width == types.BADWIDTH {
+		base.Fatalf("dgcprog: %v badwidth", t)
+	}
+	lsym := TypeSymPrefix(".gcprog", t).Linksym()
+	var p gcProg
+	p.init(lsym)
+	p.emit(t, 0)
+	offset := p.w.BitIndex() * int64(types.PtrSize)
+	p.end()
+	if ptrdata := types.PtrDataSize(t); offset < ptrdata || offset > t.Width {
+		base.Fatalf("dgcprog: %v: offset=%d but ptrdata=%d size=%d", t, offset, ptrdata, t.Width)
+	}
+	return lsym, offset
+}
+
+type gcProg struct {
+	lsym   *obj.LSym
+	symoff int
+	w      gcprog.Writer
+}
+
+func (p *gcProg) init(lsym *obj.LSym) {
+	p.lsym = lsym
+	p.symoff = 4 // first 4 bytes hold program length
+	p.w.Init(p.writeByte)
+	if base.Debug.GCProg > 0 {
+		fmt.Fprintf(os.Stderr, "compile: start GCProg for %v\n", lsym)
+		p.w.Debug(os.Stderr)
+	}
+}
+
+func (p *gcProg) writeByte(x byte) {
+	p.symoff = objw.Uint8(p.lsym, p.symoff, x)
+}
+
+func (p *gcProg) end() {
+	p.w.End()
+	objw.Uint32(p.lsym, 0, uint32(p.symoff-4))
+	objw.Global(p.lsym, int32(p.symoff), obj.DUPOK|obj.RODATA|obj.LOCAL)
+	if base.Debug.GCProg > 0 {
+		fmt.Fprintf(os.Stderr, "compile: end GCProg for %v\n", p.lsym)
+	}
+}
+
+func (p *gcProg) emit(t *types.Type, offset int64) {
+	types.CalcSize(t)
+	if !t.HasPointers() {
+		return
+	}
+	if t.Width == int64(types.PtrSize) {
+		p.w.Ptr(offset / int64(types.PtrSize))
+		return
+	}
+	switch t.Kind() {
+	default:
+		base.Fatalf("GCProg.emit: unexpected type %v", t)
+
+	case types.TSTRING:
+		p.w.Ptr(offset / int64(types.PtrSize))
+
+	case types.TINTER:
+		// Note: the first word isn't a pointer. See comment in plive.go:onebitwalktype1.
+		p.w.Ptr(offset/int64(types.PtrSize) + 1)
+
+	case types.TSLICE:
+		p.w.Ptr(offset / int64(types.PtrSize))
+
+	case types.TARRAY:
+		if t.NumElem() == 0 {
+			// should have been handled by haspointers check above
+			base.Fatalf("GCProg.emit: empty array")
+		}
+
+		// Flatten array-of-array-of-array to just a big array by multiplying counts.
+		count := t.NumElem()
+		elem := t.Elem()
+		for elem.IsArray() {
+			count *= elem.NumElem()
+			elem = elem.Elem()
+		}
+
+		if !p.w.ShouldRepeat(elem.Width/int64(types.PtrSize), count) {
+			// Cheaper to just emit the bits.
+			for i := int64(0); i < count; i++ {
+				p.emit(elem, offset+i*elem.Width)
+			}
+			return
+		}
+		p.emit(elem, offset)
+		p.w.ZeroUntil((offset + elem.Width) / int64(types.PtrSize))
+		p.w.Repeat(elem.Width/int64(types.PtrSize), count-1)
+
+	case types.TSTRUCT:
+		for _, t1 := range t.Fields().Slice() {
+			p.emit(t1.Type, offset+t1.Offset)
+		}
+	}
+}
+
+// ZeroAddr returns the address of a symbol with at least
+// size bytes of zeros.
+func ZeroAddr(size int64) ir.Node {
+	if size >= 1<<31 {
+		base.Fatalf("map elem too big %d", size)
+	}
+	if ZeroSize < size {
+		ZeroSize = size
+	}
+	s := ir.Pkgs.Map.Lookup("zero")
+	if s.Def == nil {
+		x := typecheck.NewName(s)
+		x.SetType(types.Types[types.TUINT8])
+		x.Class_ = ir.PEXTERN
+		x.SetTypecheck(1)
+		s.Def = x
+	}
+	z := typecheck.NodAddr(ir.AsNode(s.Def))
+	z.SetType(types.NewPtr(types.Types[types.TUINT8]))
+	z.SetTypecheck(1)
+	return z
+}
+
+func CollectPTabs() {
+	if !base.Ctxt.Flag_dynlink || types.LocalPkg.Name != "main" {
+		return
+	}
+	for _, exportn := range typecheck.Target.Exports {
+		s := exportn.Sym()
+		nn := ir.AsNode(s.Def)
+		if nn == nil {
+			continue
+		}
+		if nn.Op() != ir.ONAME {
+			continue
+		}
+		n := nn.(*ir.Name)
+		if !types.IsExported(s.Name) {
+			continue
+		}
+		if s.Pkg.Name != "main" {
+			continue
+		}
+		if n.Type().Kind() == types.TFUNC && n.Class_ == ir.PFUNC {
+			// function
+			ptabs = append(ptabs, ptabEntry{s: s, t: s.Def.Type()})
+		} else {
+			// variable
+			ptabs = append(ptabs, ptabEntry{s: s, t: types.NewPtr(s.Def.Type())})
+		}
+	}
+}
+
+// Generate a wrapper function to convert from
+// a receiver of type T to a receiver of type U.
+// That is,
+//
+//	func (t T) M() {
+//		...
+//	}
+//
+// already exists; this function generates
+//
+//	func (u U) M() {
+//		u.M()
+//	}
+//
+// where the types T and U are such that u.M() is valid
+// and calls the T.M method.
+// The resulting function is for use in method tables.
+//
+//	rcvr - U
+//	method - M func (t T)(), a TFIELD type struct
+//	newnam - the eventual mangled name of this function
+func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
+	if false && base.Flag.LowerR != 0 {
+		fmt.Printf("genwrapper rcvrtype=%v method=%v newnam=%v\n", rcvr, method, newnam)
+	}
+
+	// Only generate (*T).M wrappers for T.M in T's own package.
+	if rcvr.IsPtr() && rcvr.Elem() == method.Type.Recv().Type &&
+		rcvr.Elem().Sym() != nil && rcvr.Elem().Sym().Pkg != types.LocalPkg {
+		return
+	}
+
+	// Only generate I.M wrappers for I in I's own package
+	// but keep doing it for error.Error (was issue #29304).
+	if rcvr.IsInterface() && rcvr.Sym() != nil && rcvr.Sym().Pkg != types.LocalPkg && rcvr != types.ErrorType {
+		return
+	}
+
+	base.Pos = base.AutogeneratedPos
+	typecheck.DeclContext = ir.PEXTERN
+
+	tfn := ir.NewFuncType(base.Pos,
+		ir.NewField(base.Pos, typecheck.Lookup(".this"), nil, rcvr),
+		typecheck.NewFuncParams(method.Type.Params(), true),
+		typecheck.NewFuncParams(method.Type.Results(), false))
+
+	fn := typecheck.DeclFunc(newnam, tfn)
+	fn.SetDupok(true)
+
+	nthis := ir.AsNode(tfn.Type().Recv().Nname)
+
+	methodrcvr := method.Type.Recv().Type
+
+	// generate nil pointer check for better error
+	if rcvr.IsPtr() && rcvr.Elem() == methodrcvr {
+		// generating wrapper from *T to T.
+		n := ir.NewIfStmt(base.Pos, nil, nil, nil)
+		n.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, nthis, typecheck.NodNil())
+		call := ir.NewCallExpr(base.Pos, ir.OCALL, typecheck.LookupRuntime("panicwrap"), nil)
+		n.Body = []ir.Node{call}
+		fn.Body.Append(n)
+	}
+
+	dot := typecheck.AddImplicitDots(ir.NewSelectorExpr(base.Pos, ir.OXDOT, nthis, method.Sym))
+
+	// generate call
+	// It's not possible to use a tail call when dynamic linking on ppc64le. The
+	// bad scenario is when a local call is made to the wrapper: the wrapper will
+	// call the implementation, which might be in a different module and so set
+	// the TOC to the appropriate value for that module. But if it returns
+	// directly to the wrapper's caller, nothing will reset it to the correct
+	// value for that function.
+	if !base.Flag.Cfg.Instrumenting && rcvr.IsPtr() && methodrcvr.IsPtr() && method.Embedded != 0 && !types.IsInterfaceMethod(method.Type) && !(base.Ctxt.Arch.Name == "ppc64le" && base.Ctxt.Flag_dynlink) {
+		// generate tail call: adjust pointer receiver and jump to embedded method.
+		left := dot.X // skip final .M
+		if !left.Type().IsPtr() {
+			left = typecheck.NodAddr(left)
+		}
+		as := ir.NewAssignStmt(base.Pos, nthis, typecheck.ConvNop(left, rcvr))
+		fn.Body.Append(as)
+		fn.Body.Append(ir.NewBranchStmt(base.Pos, ir.ORETJMP, ir.MethodSym(methodrcvr, method.Sym)))
+	} else {
+		fn.SetWrapper(true) // ignore frame for panic+recover matching
+		call := ir.NewCallExpr(base.Pos, ir.OCALL, dot, nil)
+		call.Args.Set(ir.ParamNames(tfn.Type()))
+		call.IsDDD = tfn.Type().IsVariadic()
+		if method.Type.NumResults() > 0 {
+			ret := ir.NewReturnStmt(base.Pos, nil)
+			ret.Results = []ir.Node{call}
+			fn.Body.Append(ret)
+		} else {
+			fn.Body.Append(call)
+		}
+	}
+
+	if false && base.Flag.LowerR != 0 {
+		ir.DumpList("genwrapper body", fn.Body)
+	}
+
+	typecheck.FinishFuncBody()
+	if base.Debug.DclStack != 0 {
+		types.CheckDclstack()
+	}
+
+	typecheck.Func(fn)
+	ir.CurFunc = fn
+	typecheck.Stmts(fn.Body)
+
+	// Inline calls within (*T).M wrappers. This is safe because we only
+	// generate those wrappers within the same compilation unit as (T).M.
+	// TODO(mdempsky): Investigate why we can't enable this more generally.
+	if rcvr.IsPtr() && rcvr.Elem() == method.Type.Recv().Type && rcvr.Elem().Sym() != nil {
+		inline.InlineCalls(fn)
+	}
+	escape.Batch([]*ir.Func{fn}, false)
+
+	ir.CurFunc = nil
+	typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
+}
+
+var ZeroSize int64