go subr 源码
golang subr 代码
文件路径：/src/cmd/compile/internal/typecheck/subr.go
// 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 typecheck
import (
"bytes"
"fmt"
"sort"
"strings"
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/types"
"cmd/internal/objabi"
"cmd/internal/src"
)
func AssignConv(n ir.Node, t *types.Type, context string) ir.Node {
return assignconvfn(n, t, func() string { return context })
}
// LookupNum returns types.LocalPkg.LookupNum(prefix, n).
func LookupNum(prefix string, n int) *types.Sym {
return types.LocalPkg.LookupNum(prefix, n)
}
// Given funarg struct list, return list of fn args.
func NewFuncParams(tl *types.Type, mustname bool) []*ir.Field {
var args []*ir.Field
gen := 0
for _, t := range tl.Fields().Slice() {
s := t.Sym
if mustname && (s == nil || s.Name == "_") {
// invent a name so that we can refer to it in the trampoline
s = LookupNum(".anon", gen)
gen++
} else if s != nil && s.Pkg != types.LocalPkg {
// TODO(mdempsky): Preserve original position, name, and package.
s = Lookup(s.Name)
}
a := ir.NewField(base.Pos, s, t.Type)
a.Pos = t.Pos
a.IsDDD = t.IsDDD()
args = append(args, a)
}
return args
}
// newname returns a new ONAME Node associated with symbol s.
func NewName(s *types.Sym) *ir.Name {
n := ir.NewNameAt(base.Pos, s)
n.Curfn = ir.CurFunc
return n
}
// NodAddr returns a node representing &n at base.Pos.
func NodAddr(n ir.Node) *ir.AddrExpr {
return NodAddrAt(base.Pos, n)
}
// nodAddrPos returns a node representing &n at position pos.
func NodAddrAt(pos src.XPos, n ir.Node) *ir.AddrExpr {
n = markAddrOf(n)
return ir.NewAddrExpr(pos, n)
}
func markAddrOf(n ir.Node) ir.Node {
if IncrementalAddrtaken {
// We can only do incremental addrtaken computation when it is ok
// to typecheck the argument of the OADDR. That's only safe after the
// main typecheck has completed, and not loading the inlined body.
// The argument to OADDR needs to be typechecked because &x[i] takes
// the address of x if x is an array, but not if x is a slice.
// Note: OuterValue doesn't work correctly until n is typechecked.
n = typecheck(n, ctxExpr)
if x := ir.OuterValue(n); x.Op() == ir.ONAME {
x.Name().SetAddrtaken(true)
}
} else {
// Remember that we built an OADDR without computing the Addrtaken bit for
// its argument. We'll do that later in bulk using computeAddrtaken.
DirtyAddrtaken = true
}
return n
}
// If IncrementalAddrtaken is false, we do not compute Addrtaken for an OADDR Node
// when it is built. The Addrtaken bits are set in bulk by computeAddrtaken.
// If IncrementalAddrtaken is true, then when an OADDR Node is built the Addrtaken
// field of its argument is updated immediately.
var IncrementalAddrtaken = false
// If DirtyAddrtaken is true, then there are OADDR whose corresponding arguments
// have not yet been marked as Addrtaken.
var DirtyAddrtaken = false
func ComputeAddrtaken(top []ir.Node) {
for _, n := range top {
var doVisit func(n ir.Node)
doVisit = func(n ir.Node) {
if n.Op() == ir.OADDR {
if x := ir.OuterValue(n.(*ir.AddrExpr).X); x.Op() == ir.ONAME {
x.Name().SetAddrtaken(true)
if x.Name().IsClosureVar() {
// Mark the original variable as Addrtaken so that capturevars
// knows not to pass it by value.
x.Name().Defn.Name().SetAddrtaken(true)
}
}
}
if n.Op() == ir.OCLOSURE {
ir.VisitList(n.(*ir.ClosureExpr).Func.Body, doVisit)
}
}
ir.Visit(n, doVisit)
}
}
func NodNil() ir.Node {
n := ir.NewNilExpr(base.Pos)
n.SetType(types.Types[types.TNIL])
return n
}
// AddImplicitDots finds missing fields in obj.field that
// will give the shortest unique addressing and
// modifies the tree with missing field names.
func AddImplicitDots(n *ir.SelectorExpr) *ir.SelectorExpr {
n.X = typecheck(n.X, ctxType|ctxExpr)
t := n.X.Type()
if t == nil {
return n
}
if n.X.Op() == ir.OTYPE {
return n
}
s := n.Sel
if s == nil {
return n
}
switch path, ambig := dotpath(s, t, nil, false); {
case path != nil:
// rebuild elided dots
for c := len(path) - 1; c >= 0; c-- {
dot := ir.NewSelectorExpr(n.Pos(), ir.ODOT, n.X, path[c].field.Sym)
dot.SetImplicit(true)
dot.SetType(path[c].field.Type)
n.X = dot
}
case ambig:
base.Errorf("ambiguous selector %v", n)
n.X = nil
}
return n
}
// CalcMethods calculates all the methods (including embedding) of a non-interface
// type t.
func CalcMethods(t *types.Type) {
if t == nil || t.AllMethods().Len() != 0 {
return
}
// mark top-level method symbols
// so that expand1 doesn't consider them.
for _, f := range t.Methods().Slice() {
f.Sym.SetUniq(true)
}
// generate all reachable methods
slist = slist[:0]
expand1(t, true)
// check each method to be uniquely reachable
var ms []*types.Field
for i, sl := range slist {
slist[i].field = nil
sl.field.Sym.SetUniq(false)
var f *types.Field
path, _ := dotpath(sl.field.Sym, t, &f, false)
if path == nil {
continue
}
// dotpath may have dug out arbitrary fields, we only want methods.
if !f.IsMethod() {
continue
}
// add it to the base type method list
f = f.Copy()
f.Embedded = 1 // needs a trampoline
for _, d := range path {
if d.field.Type.IsPtr() {
f.Embedded = 2
break
}
}
ms = append(ms, f)
}
for _, f := range t.Methods().Slice() {
f.Sym.SetUniq(false)
}
ms = append(ms, t.Methods().Slice()...)
sort.Sort(types.MethodsByName(ms))
t.SetAllMethods(ms)
}
// adddot1 returns the number of fields or methods named s at depth d in Type t.
// If exactly one exists, it will be returned in *save (if save is not nil),
// and dotlist will contain the path of embedded fields traversed to find it,
// in reverse order. If none exist, more will indicate whether t contains any
// embedded fields at depth d, so callers can decide whether to retry at
// a greater depth.
func adddot1(s *types.Sym, t *types.Type, d int, save **types.Field, ignorecase bool) (c int, more bool) {
if t.Recur() {
return
}
t.SetRecur(true)
defer t.SetRecur(false)
var u *types.Type
d--
if d < 0 {
// We've reached our target depth. If t has any fields/methods
// named s, then we're done. Otherwise, we still need to check
// below for embedded fields.
c = lookdot0(s, t, save, ignorecase)
if c != 0 {
return c, false
}
}
u = t
if u.IsPtr() {
u = u.Elem()
}
if !u.IsStruct() && !u.IsInterface() {
return c, false
}
var fields *types.Fields
if u.IsStruct() {
fields = u.Fields()
} else {
fields = u.AllMethods()
}
for _, f := range fields.Slice() {
if f.Embedded == 0 || f.Sym == nil {
continue
}
if d < 0 {
// Found an embedded field at target depth.
return c, true
}
a, more1 := adddot1(s, f.Type, d, save, ignorecase)
if a != 0 && c == 0 {
dotlist[d].field = f
}
c += a
if more1 {
more = true
}
}
return c, more
}
// dotlist is used by adddot1 to record the path of embedded fields
// used to access a target field or method.
// Must be non-nil so that dotpath returns a non-nil slice even if d is zero.
var dotlist = make([]dlist, 10)
// Convert node n for assignment to type t.
func assignconvfn(n ir.Node, t *types.Type, context func() string) ir.Node {
if n == nil || n.Type() == nil {
return n
}
if t.Kind() == types.TBLANK && n.Type().Kind() == types.TNIL {
base.Errorf("use of untyped nil")
}
n = convlit1(n, t, false, context)
if n.Type() == nil {
return n
}
if t.Kind() == types.TBLANK {
return n
}
// Convert ideal bool from comparison to plain bool
// if the next step is non-bool (like interface{}).
if n.Type() == types.UntypedBool && !t.IsBoolean() {
if n.Op() == ir.ONAME || n.Op() == ir.OLITERAL {
r := ir.NewConvExpr(base.Pos, ir.OCONVNOP, nil, n)
r.SetType(types.Types[types.TBOOL])
r.SetTypecheck(1)
r.SetImplicit(true)
n = r
}
}
if types.Identical(n.Type(), t) {
return n
}
op, why := Assignop(n.Type(), t)
if op == ir.OXXX {
base.Errorf("cannot use %L as type %v in %s%s", n, t, context(), why)
op = ir.OCONV
}
r := ir.NewConvExpr(base.Pos, op, t, n)
r.SetTypecheck(1)
r.SetImplicit(true)
return r
}
// Is type src assignment compatible to type dst?
// If so, return op code to use in conversion.
// If not, return OXXX. In this case, the string return parameter may
// hold a reason why. In all other cases, it'll be the empty string.
func Assignop(src, dst *types.Type) (ir.Op, string) {
if src == dst {
return ir.OCONVNOP, ""
}
if src == nil || dst == nil || src.Kind() == types.TFORW || dst.Kind() == types.TFORW || src.Underlying() == nil || dst.Underlying() == nil {
return ir.OXXX, ""
}
// 1. src type is identical to dst.
if types.Identical(src, dst) {
return ir.OCONVNOP, ""
}
return Assignop1(src, dst)
}
func Assignop1(src, dst *types.Type) (ir.Op, string) {
// 2. src and dst have identical underlying types and
// a. either src or dst is not a named type, or
// b. both are empty interface types, or
// c. at least one is a gcshape type.
// For assignable but different non-empty interface types,
// we want to recompute the itab. Recomputing the itab ensures
// that itabs are unique (thus an interface with a compile-time
// type I has an itab with interface type I).
if types.Identical(src.Underlying(), dst.Underlying()) {
if src.IsEmptyInterface() {
// Conversion between two empty interfaces
// requires no code.
return ir.OCONVNOP, ""
}
if (src.Sym() == nil || dst.Sym() == nil) && !src.IsInterface() {
// Conversion between two types, at least one unnamed,
// needs no conversion. The exception is nonempty interfaces
// which need to have their itab updated.
return ir.OCONVNOP, ""
}
if src.IsShape() || dst.IsShape() {
// Conversion between a shape type and one of the types
// it represents also needs no conversion.
return ir.OCONVNOP, ""
}
}
// 3. dst is an interface type and src implements dst.
if dst.IsInterface() && src.Kind() != types.TNIL {
var missing, have *types.Field
var ptr int
if src.IsShape() {
// Shape types implement things they have already
// been typechecked to implement, even if they
// don't have the methods for them.
return ir.OCONVIFACE, ""
}
if implements(src, dst, &missing, &have, &ptr) {
return ir.OCONVIFACE, ""
}
var why string
if isptrto(src, types.TINTER) {
why = fmt.Sprintf(":\n\t%v is pointer to interface, not interface", src)
} else if have != nil && have.Sym == missing.Sym && have.Nointerface() {
why = fmt.Sprintf(":\n\t%v does not implement %v (%v method is marked 'nointerface')", src, dst, missing.Sym)
} else if have != nil && have.Sym == missing.Sym {
why = fmt.Sprintf(":\n\t%v does not implement %v (wrong type for %v method)\n"+
"\t\thave %v%S\n\t\twant %v%S", src, dst, missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
} else if ptr != 0 {
why = fmt.Sprintf(":\n\t%v does not implement %v (%v method has pointer receiver)", src, dst, missing.Sym)
} else if have != nil {
why = fmt.Sprintf(":\n\t%v does not implement %v (missing %v method)\n"+
"\t\thave %v%S\n\t\twant %v%S", src, dst, missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
} else {
why = fmt.Sprintf(":\n\t%v does not implement %v (missing %v method)", src, dst, missing.Sym)
}
return ir.OXXX, why
}
if isptrto(dst, types.TINTER) {
why := fmt.Sprintf(":\n\t%v is pointer to interface, not interface", dst)
return ir.OXXX, why
}
if src.IsInterface() && dst.Kind() != types.TBLANK {
var missing, have *types.Field
var ptr int
var why string
if implements(dst, src, &missing, &have, &ptr) {
why = ": need type assertion"
}
return ir.OXXX, why
}
// 4. src is a bidirectional channel value, dst is a channel type,
// src and dst have identical element types, and
// either src or dst is not a named type.
if src.IsChan() && src.ChanDir() == types.Cboth && dst.IsChan() {
if types.Identical(src.Elem(), dst.Elem()) && (src.Sym() == nil || dst.Sym() == nil) {
return ir.OCONVNOP, ""
}
}
// 5. src is the predeclared identifier nil and dst is a nillable type.
if src.Kind() == types.TNIL {
switch dst.Kind() {
case types.TPTR,
types.TFUNC,
types.TMAP,
types.TCHAN,
types.TINTER,
types.TSLICE:
return ir.OCONVNOP, ""
}
}
// 6. rule about untyped constants - already converted by DefaultLit.
// 7. Any typed value can be assigned to the blank identifier.
if dst.Kind() == types.TBLANK {
return ir.OCONVNOP, ""
}
return ir.OXXX, ""
}
// Can we convert a value of type src to a value of type dst?
// If so, return op code to use in conversion (maybe OCONVNOP).
// If not, return OXXX. In this case, the string return parameter may
// hold a reason why. In all other cases, it'll be the empty string.
// srcConstant indicates whether the value of type src is a constant.
func Convertop(srcConstant bool, src, dst *types.Type) (ir.Op, string) {
if src == dst {
return ir.OCONVNOP, ""
}
if src == nil || dst == nil {
return ir.OXXX, ""
}
// Conversions from regular to go:notinheap are not allowed
// (unless it's unsafe.Pointer). These are runtime-specific
// rules.
// (a) Disallow (*T) to (*U) where T is go:notinheap but U isn't.
if src.IsPtr() && dst.IsPtr() && dst.Elem().NotInHeap() && !src.Elem().NotInHeap() {
why := fmt.Sprintf(":\n\t%v is incomplete (or unallocatable), but %v is not", dst.Elem(), src.Elem())
return ir.OXXX, why
}
// (b) Disallow string to []T where T is go:notinheap.
if src.IsString() && dst.IsSlice() && dst.Elem().NotInHeap() && (dst.Elem().Kind() == types.ByteType.Kind() || dst.Elem().Kind() == types.RuneType.Kind()) {
why := fmt.Sprintf(":\n\t%v is incomplete (or unallocatable)", dst.Elem())
return ir.OXXX, why
}
// 1. src can be assigned to dst.
op, why := Assignop(src, dst)
if op != ir.OXXX {
return op, why
}
// The rules for interfaces are no different in conversions
// than assignments. If interfaces are involved, stop now
// with the good message from assignop.
// Otherwise clear the error.
if src.IsInterface() || dst.IsInterface() {
return ir.OXXX, why
}
// 2. Ignoring struct tags, src and dst have identical underlying types.
if types.IdenticalIgnoreTags(src.Underlying(), dst.Underlying()) {
return ir.OCONVNOP, ""
}
// 3. src and dst are unnamed pointer types and, ignoring struct tags,
// their base types have identical underlying types.
if src.IsPtr() && dst.IsPtr() && src.Sym() == nil && dst.Sym() == nil {
if types.IdenticalIgnoreTags(src.Elem().Underlying(), dst.Elem().Underlying()) {
return ir.OCONVNOP, ""
}
}
// 4. src and dst are both integer or floating point types.
if (src.IsInteger() || src.IsFloat()) && (dst.IsInteger() || dst.IsFloat()) {
if types.SimType[src.Kind()] == types.SimType[dst.Kind()] {
return ir.OCONVNOP, ""
}
return ir.OCONV, ""
}
// 5. src and dst are both complex types.
if src.IsComplex() && dst.IsComplex() {
if types.SimType[src.Kind()] == types.SimType[dst.Kind()] {
return ir.OCONVNOP, ""
}
return ir.OCONV, ""
}
// Special case for constant conversions: any numeric
// conversion is potentially okay. We'll validate further
// within evconst. See #38117.
if srcConstant && (src.IsInteger() || src.IsFloat() || src.IsComplex()) && (dst.IsInteger() || dst.IsFloat() || dst.IsComplex()) {
return ir.OCONV, ""
}
// 6. src is an integer or has type []byte or []rune
// and dst is a string type.
if src.IsInteger() && dst.IsString() {
return ir.ORUNESTR, ""
}
if src.IsSlice() && dst.IsString() {
if src.Elem().Kind() == types.ByteType.Kind() {
return ir.OBYTES2STR, ""
}
if src.Elem().Kind() == types.RuneType.Kind() {
return ir.ORUNES2STR, ""
}
}
// 7. src is a string and dst is []byte or []rune.
// String to slice.
if src.IsString() && dst.IsSlice() {
if dst.Elem().Kind() == types.ByteType.Kind() {
return ir.OSTR2BYTES, ""
}
if dst.Elem().Kind() == types.RuneType.Kind() {
return ir.OSTR2RUNES, ""
}
}
// 8. src is a pointer or uintptr and dst is unsafe.Pointer.
if (src.IsPtr() || src.IsUintptr()) && dst.IsUnsafePtr() {
return ir.OCONVNOP, ""
}
// 9. src is unsafe.Pointer and dst is a pointer or uintptr.
if src.IsUnsafePtr() && (dst.IsPtr() || dst.IsUintptr()) {
return ir.OCONVNOP, ""
}
// 10. src is map and dst is a pointer to corresponding hmap.
// This rule is needed for the implementation detail that
// go gc maps are implemented as a pointer to a hmap struct.
if src.Kind() == types.TMAP && dst.IsPtr() &&
src.MapType().Hmap == dst.Elem() {
return ir.OCONVNOP, ""
}
// 11. src is a slice and dst is a pointer-to-array.
// They must have same element type.
if src.IsSlice() && dst.IsPtr() && dst.Elem().IsArray() &&
types.Identical(src.Elem(), dst.Elem().Elem()) {
return ir.OSLICE2ARRPTR, ""
}
return ir.OXXX, ""
}
// Code to resolve elided DOTs in embedded types.
// A dlist stores a pointer to a TFIELD Type embedded within
// a TSTRUCT or TINTER Type.
type dlist struct {
field *types.Field
}
// dotpath computes the unique shortest explicit selector path to fully qualify
// a selection expression x.f, where x is of type t and f is the symbol s.
// If no such path exists, dotpath returns nil.
// If there are multiple shortest paths to the same depth, ambig is true.
func dotpath(s *types.Sym, t *types.Type, save **types.Field, ignorecase bool) (path []dlist, ambig bool) {
// The embedding of types within structs imposes a tree structure onto
// types: structs parent the types they embed, and types parent their
// fields or methods. Our goal here is to find the shortest path to
// a field or method named s in the subtree rooted at t. To accomplish
// that, we iteratively perform depth-first searches of increasing depth
// until we either find the named field/method or exhaust the tree.
for d := 0; ; d++ {
if d > len(dotlist) {
dotlist = append(dotlist, dlist{})
}
if c, more := adddot1(s, t, d, save, ignorecase); c == 1 {
return dotlist[:d], false
} else if c > 1 {
return nil, true
} else if !more {
return nil, false
}
}
}
func expand0(t *types.Type) {
u := t
if u.IsPtr() {
u = u.Elem()
}
if u.IsInterface() {
for _, f := range u.AllMethods().Slice() {
if f.Sym.Uniq() {
continue
}
f.Sym.SetUniq(true)
slist = append(slist, symlink{field: f})
}
return
}
u = types.ReceiverBaseType(t)
if u != nil {
for _, f := range u.Methods().Slice() {
if f.Sym.Uniq() {
continue
}
f.Sym.SetUniq(true)
slist = append(slist, symlink{field: f})
}
}
}
func expand1(t *types.Type, top bool) {
if t.Recur() {
return
}
t.SetRecur(true)
if !top {
expand0(t)
}
u := t
if u.IsPtr() {
u = u.Elem()
}
if u.IsStruct() || u.IsInterface() {
var fields *types.Fields
if u.IsStruct() {
fields = u.Fields()
} else {
fields = u.AllMethods()
}
for _, f := range fields.Slice() {
if f.Embedded == 0 {
continue
}
if f.Sym == nil {
continue
}
expand1(f.Type, false)
}
}
t.SetRecur(false)
}
func ifacelookdot(s *types.Sym, t *types.Type, ignorecase bool) (m *types.Field, followptr bool) {
if t == nil {
return nil, false
}
path, ambig := dotpath(s, t, &m, ignorecase)
if path == nil {
if ambig {
base.Errorf("%v.%v is ambiguous", t, s)
}
return nil, false
}
for _, d := range path {
if d.field.Type.IsPtr() {
followptr = true
break
}
}
if !m.IsMethod() {
base.Errorf("%v.%v is a field, not a method", t, s)
return nil, followptr
}
return m, followptr
}
// implements reports whether t implements the interface iface. t can be
// an interface, a type parameter, or a concrete type. If implements returns
// false, it stores a method of iface that is not implemented in *m. If the
// method name matches but the type is wrong, it additionally stores the type
// of the method (on t) in *samename.
func implements(t, iface *types.Type, m, samename **types.Field, ptr *int) bool {
t0 := t
if t == nil {
return false
}
if t.IsInterface() || t.IsTypeParam() {
if t.IsTypeParam() {
// If t is a simple type parameter T, its type and underlying is the same.
// If t is a type definition:'type P[T any] T', its type is P[T] and its
// underlying is T. Therefore we use 't.Underlying() != t' to distinguish them.
if t.Underlying() != t {
CalcMethods(t)
} else {
// A typeparam satisfies an interface if its type bound
// has all the methods of that interface.
t = t.Bound()
}
}
i := 0
tms := t.AllMethods().Slice()
for _, im := range iface.AllMethods().Slice() {
for i < len(tms) && tms[i].Sym != im.Sym {
i++
}
if i == len(tms) {
*m = im
*samename = nil
*ptr = 0
return false
}
tm := tms[i]
if !types.Identical(tm.Type, im.Type) {
*m = im
*samename = tm
*ptr = 0
return false
}
}
return true
}
t = types.ReceiverBaseType(t)
var tms []*types.Field
if t != nil {
CalcMethods(t)
tms = t.AllMethods().Slice()
}
i := 0
for _, im := range iface.AllMethods().Slice() {
for i < len(tms) && tms[i].Sym != im.Sym {
i++
}
if i == len(tms) {
*m = im
*samename, _ = ifacelookdot(im.Sym, t, true)
*ptr = 0
return false
}
tm := tms[i]
if tm.Nointerface() || !types.Identical(tm.Type, im.Type) {
*m = im
*samename = tm
*ptr = 0
return false
}
followptr := tm.Embedded == 2
// if pointer receiver in method,
// the method does not exist for value types.
rcvr := tm.Type.Recv().Type
if rcvr.IsPtr() && !t0.IsPtr() && !followptr && !types.IsInterfaceMethod(tm.Type) {
if false && base.Flag.LowerR != 0 {
base.Errorf("interface pointer mismatch")
}
*m = im
*samename = nil
*ptr = 1
return false
}
}
return true
}
func isptrto(t *types.Type, et types.Kind) bool {
if t == nil {
return false
}
if !t.IsPtr() {
return false
}
t = t.Elem()
if t == nil {
return false
}
if t.Kind() != et {
return false
}
return true
}
// lookdot0 returns the number of fields or methods named s associated
// with Type t. If exactly one exists, it will be returned in *save
// (if save is not nil).
func lookdot0(s *types.Sym, t *types.Type, save **types.Field, ignorecase bool) int {
u := t
if u.IsPtr() {
u = u.Elem()
}
c := 0
if u.IsStruct() || u.IsInterface() {
var fields *types.Fields
if u.IsStruct() {
fields = u.Fields()
} else {
fields = u.AllMethods()
}
for _, f := range fields.Slice() {
if f.Sym == s || (ignorecase && f.IsMethod() && strings.EqualFold(f.Sym.Name, s.Name)) {
if save != nil {
*save = f
}
c++
}
}
}
u = t
if t.Sym() != nil && t.IsPtr() && !t.Elem().IsPtr() {
// If t is a defined pointer type, then x.m is shorthand for (*x).m.
u = t.Elem()
}
u = types.ReceiverBaseType(u)
if u != nil {
for _, f := range u.Methods().Slice() {
if f.Embedded == 0 && (f.Sym == s || (ignorecase && strings.EqualFold(f.Sym.Name, s.Name))) {
if save != nil {
*save = f
}
c++
}
}
}
return c
}
var slist []symlink
// Code to help generate trampoline functions for methods on embedded
// types. These are approx the same as the corresponding AddImplicitDots
// routines except that they expect to be called with unique tasks and
// they return the actual methods.
type symlink struct {
field *types.Field
}
// TypesOf converts a list of nodes to a list
// of types of those nodes.
func TypesOf(x []ir.Ntype) []*types.Type {
r := make([]*types.Type, len(x))
for i, n := range x {
r[i] = n.Type()
}
return r
}
// addTargs writes out the targs to buffer b as a comma-separated list enclosed by
// brackets.
func addTargs(b *bytes.Buffer, targs []*types.Type) {
b.WriteByte('[')
for i, targ := range targs {
if i > 0 {
b.WriteByte(',')
}
// Make sure that type arguments (including type params), are
// uniquely specified. LinkString() eliminates all spaces
// and includes the package path (local package path is "" before
// linker substitution).
tstring := targ.LinkString()
b.WriteString(tstring)
}
b.WriteString("]")
}
// InstTypeName creates a name for an instantiated type, based on the name of the
// generic type and the type args.
func InstTypeName(name string, targs []*types.Type) string {
b := bytes.NewBufferString(name)
addTargs(b, targs)
return b.String()
}
// makeInstName1 returns the name of the generic function instantiated with the
// given types, which can have type params or shapes, or be concrete types. name is
// the name of the generic function or method.
func makeInstName1(name string, targs []*types.Type, hasBrackets bool) string {
b := bytes.NewBufferString("")
i := strings.Index(name, "[")
assert(hasBrackets == (i >= 0))
if i >= 0 {
b.WriteString(name[0:i])
} else {
b.WriteString(name)
}
addTargs(b, targs)
if i >= 0 {
i2 := strings.LastIndex(name[i:], "]")
assert(i2 >= 0)
b.WriteString(name[i+i2+1:])
}
return b.String()
}
// MakeFuncInstSym makes the unique sym for a stenciled generic function or method,
// based on the name of the function gf and the targs. It replaces any
// existing bracket type list in the name. MakeInstName asserts that gf has
// brackets in its name if and only if hasBrackets is true.
//
// Names of declared generic functions have no brackets originally, so hasBrackets
// should be false. Names of generic methods already have brackets, since the new
// type parameter is specified in the generic type of the receiver (e.g. func
// (func (v *value[T]).set(...) { ... } has the original name (*value[T]).set.
//
// The standard naming is something like: 'genFn[int,bool]' for functions and
// '(*genType[int,bool]).methodName' for methods
//
// isMethodNode specifies if the name of a method node is being generated (as opposed
// to a name of an instantiation of generic function or name of the shape-based
// function that helps implement a method of an instantiated type). For method nodes
// on shape types, we prepend "nofunc.", because method nodes for shape types will
// have no body, and we want to avoid a name conflict with the shape-based function
// that helps implement the same method for fully-instantiated types. Function names
// are also created at the end of (*Tsubster).typ1, so we append "nofunc" there as
// well, as needed.
func MakeFuncInstSym(gf *types.Sym, targs []*types.Type, isMethodNode, hasBrackets bool) *types.Sym {
nm := makeInstName1(gf.Name, targs, hasBrackets)
if targs[0].HasShape() && isMethodNode {
nm = "nofunc." + nm
}
return gf.Pkg.Lookup(nm)
}
func MakeDictSym(gf *types.Sym, targs []*types.Type, hasBrackets bool) *types.Sym {
for _, targ := range targs {
if targ.HasTParam() {
fmt.Printf("FUNCTION %s\n", gf.Name)
for _, targ := range targs {
fmt.Printf(" PARAM %+v\n", targ)
}
panic("dictionary should always have concrete type args")
}
}
name := makeInstName1(gf.Name, targs, hasBrackets)
name = fmt.Sprintf("%s.%s", objabi.GlobalDictPrefix, name)
return gf.Pkg.Lookup(name)
}
func assert(p bool) {
base.Assert(p)
}
// List of newly fully-instantiated types who should have their methods generated.
var instTypeList []*types.Type
// NeedInstType adds a new fully-instantiated type to instTypeList.
func NeedInstType(t *types.Type) {
instTypeList = append(instTypeList, t)
}
// GetInstTypeList returns the current contents of instTypeList.
func GetInstTypeList() []*types.Type {
r := instTypeList
return r
}
// ClearInstTypeList clears the contents of instTypeList.
func ClearInstTypeList() {
instTypeList = nil
}
// General type substituter, for replacing typeparams with type args.
type Tsubster struct {
Tparams []*types.Type
Targs []*types.Type
// If non-nil, the substitution map from name nodes in the generic function to the
// name nodes in the new stenciled function.
Vars map[*ir.Name]*ir.Name
// If non-nil, function to substitute an incomplete (TFORW) type.
SubstForwFunc func(*types.Type) *types.Type
// Prevent endless recursion on functions. See #51832.
Funcs map[*types.Type]bool
}
// Typ computes the type obtained by substituting any type parameter or shape in t
// that appears in subst.Tparams with the corresponding type argument in subst.Targs.
// If t contains no type parameters, the result is t; otherwise the result is a new
// type. It deals with recursive types by using TFORW types and finding partially or
// fully created types via sym.Def.
func (ts *Tsubster) Typ(t *types.Type) *types.Type {
// Defer the CheckSize calls until we have fully-defined
// (possibly-recursive) top-level type.
types.DeferCheckSize()
r := ts.typ1(t)
types.ResumeCheckSize()
return r
}
func (ts *Tsubster) typ1(t *types.Type) *types.Type {
hasParamOrShape := t.HasTParam() || t.HasShape()
if !hasParamOrShape && t.Kind() != types.TFUNC {
// Note: function types need to be copied regardless, as the
// types of closures may contain declarations that need
// to be copied. See #45738.
return t
}
if t.IsTypeParam() || t.IsShape() {
for i, tp := range ts.Tparams {
if tp == t {
return ts.Targs[i]
}
}
// If t is a simple typeparam T, then t has the name/symbol 'T'
// and t.Underlying() == t.
//
// However, consider the type definition: 'type P[T any] T'. We
// might use this definition so we can have a variant of type T
// that we can add new methods to. Suppose t is a reference to
// P[T]. t has the name 'P[T]', but its kind is TTYPEPARAM,
// because P[T] is defined as T. If we look at t.Underlying(), it
// is different, because the name of t.Underlying() is 'T' rather
// than 'P[T]'. But the kind of t.Underlying() is also TTYPEPARAM.
// In this case, we do the needed recursive substitution in the
// case statement below.
if t.Underlying() == t {
// t is a simple typeparam that didn't match anything in tparam
return t
}
// t is a more complex typeparam (e.g. P[T], as above, whose
// definition is just T).
assert(t.Sym() != nil)
}
var newsym *types.Sym
var neededTargs []*types.Type
var targsChanged bool // == are there any substitutions from this
var forw *types.Type
if t.Sym() != nil && hasParamOrShape {
// Need to test for t.HasTParam() again because of special TFUNC case above.
// Translate the type params for this type according to
// the tparam/targs mapping from subst.
neededTargs = make([]*types.Type, len(t.RParams()))
for i, rparam := range t.RParams() {
neededTargs[i] = ts.typ1(rparam)
if !types.IdenticalStrict(neededTargs[i], rparam) {
targsChanged = true
}
}
// For a named (defined) type, we have to change the name of the
// type as well. We do this first, so we can look up if we've
// already seen this type during this substitution or other
// definitions/substitutions.
genName := genericTypeName(t.Sym())
newsym = t.Sym().Pkg.Lookup(InstTypeName(genName, neededTargs))
if newsym.Def != nil {
// We've already created this instantiated defined type.
return newsym.Def.Type()
}
// In order to deal with recursive generic types, create a TFORW
// type initially and set the Def field of its sym, so it can be
// found if this type appears recursively within the type.
forw = NewIncompleteNamedType(t.Pos(), newsym)
//println("Creating new type by sub", newsym.Name, forw.HasTParam())
forw.SetRParams(neededTargs)
// Copy the OrigType from the re-instantiated type (which is the sym of
// the base generic type).
assert(t.OrigType() != nil)
forw.SetOrigType(t.OrigType())
}
var newt *types.Type
switch t.Kind() {
case types.TTYPEPARAM:
if t.Sym() == newsym && !targsChanged {
// The substitution did not change the type.
return t
}
// Substitute the underlying typeparam (e.g. T in P[T], see
// the example describing type P[T] above).
newt = ts.typ1(t.Underlying())
assert(newt != t)
case types.TARRAY:
elem := t.Elem()
newelem := ts.typ1(elem)
if newelem != elem || targsChanged {
newt = types.NewArray(newelem, t.NumElem())
}
case types.TPTR:
elem := t.Elem()
newelem := ts.typ1(elem)
if newelem != elem || targsChanged {
newt = types.NewPtr(newelem)
}
case types.TSLICE:
elem := t.Elem()
newelem := ts.typ1(elem)
if newelem != elem || targsChanged {
newt = types.NewSlice(newelem)
}
case types.TSTRUCT:
newt = ts.tstruct(t, targsChanged)
if newt == t {
newt = nil
}
case types.TFUNC:
// watch out for endless recursion on plain function types that mention themselves, e.g. "type T func() T"
if !hasParamOrShape {
if ts.Funcs[t] { // Visit such function types only once.
return t
}
if ts.Funcs == nil {
// allocate lazily
ts.Funcs = make(map[*types.Type]bool)
}
ts.Funcs[t] = true
}
newrecvs := ts.tstruct(t.Recvs(), false)
newparams := ts.tstruct(t.Params(), false)
newresults := ts.tstruct(t.Results(), false)
// Translate the tparams of a signature.
newtparams := ts.tstruct(t.TParams(), false)
if newrecvs != t.Recvs() || newparams != t.Params() ||
newresults != t.Results() || newtparams != t.TParams() || targsChanged {
// If any types have changed, then the all the fields of
// of recv, params, and results must be copied, because they have
// offset fields that are dependent, and so must have an
// independent copy for each new signature.
var newrecv *types.Field
if newrecvs.NumFields() > 0 {
if newrecvs == t.Recvs() {
newrecvs = ts.tstruct(t.Recvs(), true)
}
newrecv = newrecvs.Field(0)
}
if newparams == t.Params() {
newparams = ts.tstruct(t.Params(), true)
}
if newresults == t.Results() {
newresults = ts.tstruct(t.Results(), true)
}
var tparamfields []*types.Field
if newtparams.HasTParam() {
tparamfields = newtparams.FieldSlice()
} else {
// Completely remove the tparams from the resulting
// signature, if the tparams are now concrete types.
tparamfields = nil
}
newt = types.NewSignature(t.Pkg(), newrecv, tparamfields,
newparams.FieldSlice(), newresults.FieldSlice())
}
if !hasParamOrShape {
delete(ts.Funcs, t)
}
case types.TINTER:
newt = ts.tinter(t, targsChanged)
if newt == t {
newt = nil
}
case types.TMAP:
newkey := ts.typ1(t.Key())
newval := ts.typ1(t.Elem())
if newkey != t.Key() || newval != t.Elem() || targsChanged {
newt = types.NewMap(newkey, newval)
}
case types.TCHAN:
elem := t.Elem()
newelem := ts.typ1(elem)
if newelem != elem || targsChanged {
newt = types.NewChan(newelem, t.ChanDir())
}
case types.TFORW:
if ts.SubstForwFunc != nil {
return ts.SubstForwFunc(forw)
} else {
assert(false)
}
case types.TINT, types.TINT8, types.TINT16, types.TINT32, types.TINT64,
types.TUINT, types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64,
types.TUINTPTR, types.TBOOL, types.TSTRING, types.TFLOAT32, types.TFLOAT64, types.TCOMPLEX64, types.TCOMPLEX128, types.TUNSAFEPTR:
newt = t.Underlying()
case types.TUNION:
nt := t.NumTerms()
newterms := make([]*types.Type, nt)
tildes := make([]bool, nt)
changed := false
for i := 0; i < nt; i++ {
term, tilde := t.Term(i)
tildes[i] = tilde
newterms[i] = ts.typ1(term)
if newterms[i] != term {
changed = true
}
}
if changed {
newt = types.NewUnion(newterms, tildes)
}
default:
panic(fmt.Sprintf("Bad type in (*TSubster).Typ: %v", t.Kind()))
}
if newt == nil {
// Even though there were typeparams in the type, there may be no
// change if this is a function type for a function call (which will
// have its own tparams/targs in the function instantiation).
return t
}
if forw != nil {
forw.SetUnderlying(newt)
newt = forw
}
if !newt.HasTParam() && !newt.IsFuncArgStruct() {
// Calculate the size of any new types created. These will be
// deferred until the top-level ts.Typ() or g.typ() (if this is
// called from g.fillinMethods()).
types.CheckSize(newt)
}
if t.Kind() != types.TINTER && t.Methods().Len() > 0 {
// Fill in the method info for the new type.
var newfields []*types.Field
newfields = make([]*types.Field, t.Methods().Len())
for i, f := range t.Methods().Slice() {
t2 := ts.typ1(f.Type)
oldsym := f.Nname.Sym()
// Use the name of the substituted receiver to create the
// method name, since the receiver name may have many levels
// of nesting (brackets) with type names to be substituted.
recvType := t2.Recv().Type
var nm string
if recvType.IsPtr() {
recvType = recvType.Elem()
nm = "(*" + recvType.Sym().Name + ")." + f.Sym.Name
} else {
nm = recvType.Sym().Name + "." + f.Sym.Name
}
if recvType.RParams()[0].HasShape() {
// We add "nofunc" to methods of shape type to avoid
// conflict with the name of the shape-based helper
// function. See header comment of MakeFuncInstSym.
nm = "nofunc." + nm
}
newsym := oldsym.Pkg.Lookup(nm)
var nname *ir.Name
if newsym.Def != nil {
nname = newsym.Def.(*ir.Name)
} else {
nname = ir.NewNameAt(f.Pos, newsym)
nname.SetType(t2)
ir.MarkFunc(nname)
newsym.Def = nname
}
newfields[i] = types.NewField(f.Pos, f.Sym, t2)
newfields[i].Nname = nname
}
newt.Methods().Set(newfields)
if !newt.HasTParam() && !newt.HasShape() {
// Generate all the methods for a new fully-instantiated type.
NeedInstType(newt)
}
}
return newt
}
// tstruct substitutes type params in types of the fields of a structure type. For
// each field, tstruct copies the Nname, and translates it if Nname is in
// ts.vars. To always force the creation of a new (top-level) struct,
// regardless of whether anything changed with the types or names of the struct's
// fields, set force to true.
func (ts *Tsubster) tstruct(t *types.Type, force bool) *types.Type {
if t.NumFields() == 0 {
if t.HasTParam() || t.HasShape() {
// For an empty struct, we need to return a new type, if
// substituting from a generic type or shape type, since it
// will change HasTParam/HasShape flags.
return types.NewStruct(t.Pkg(), nil)
}
return t
}
var newfields []*types.Field
if force {
newfields = make([]*types.Field, t.NumFields())
}
for i, f := range t.Fields().Slice() {
t2 := ts.typ1(f.Type)
if (t2 != f.Type || f.Nname != nil) && newfields == nil {
newfields = make([]*types.Field, t.NumFields())
for j := 0; j < i; j++ {
newfields[j] = t.Field(j)
}
}
if newfields != nil {
newfields[i] = types.NewField(f.Pos, f.Sym, t2)
newfields[i].Embedded = f.Embedded
newfields[i].Note = f.Note
if f.IsDDD() {
newfields[i].SetIsDDD(true)
}
if f.Nointerface() {
newfields[i].SetNointerface(true)
}
if f.Nname != nil && ts.Vars != nil {
v := ts.Vars[f.Nname.(*ir.Name)]
if v != nil {
// This is the case where we are
// translating the type of the function we
// are substituting, so its dcls are in
// the subst.ts.vars table, and we want to
// change to reference the new dcl.
newfields[i].Nname = v
} else {
// This is the case where we are
// translating the type of a function
// reference inside the function we are
// substituting, so we leave the Nname
// value as is.
newfields[i].Nname = f.Nname
}
}
}
}
if newfields != nil {
news := types.NewStruct(t.Pkg(), newfields)
news.StructType().Funarg = t.StructType().Funarg
return news
}
return t
}
// tinter substitutes type params in types of the methods of an interface type.
func (ts *Tsubster) tinter(t *types.Type, force bool) *types.Type {
if t.Methods().Len() == 0 {
if t.HasTParam() || t.HasShape() {
// For an empty interface, we need to return a new type, if
// substituting from a generic type or shape type, since
// since it will change HasTParam/HasShape flags.
return types.NewInterface(t.Pkg(), nil, false)
}
return t
}
var newfields []*types.Field
if force {
newfields = make([]*types.Field, t.Methods().Len())
}
for i, f := range t.Methods().Slice() {
t2 := ts.typ1(f.Type)
if (t2 != f.Type || f.Nname != nil) && newfields == nil {
newfields = make([]*types.Field, t.Methods().Len())
for j := 0; j < i; j++ {
newfields[j] = t.Methods().Index(j)
}
}
if newfields != nil {
newfields[i] = types.NewField(f.Pos, f.Sym, t2)
}
}
if newfields != nil {
return types.NewInterface(t.Pkg(), newfields, t.IsImplicit())
}
return t
}
// genericSym returns the name of the base generic type for the type named by
// sym. It simply returns the name obtained by removing everything after the
// first bracket ("[").
func genericTypeName(sym *types.Sym) string {
return sym.Name[0:strings.Index(sym.Name, "[")]
}
// getShapes appends the list of the shape types that are used within type t to
// listp. The type traversal is simplified for two reasons: (1) we can always stop a
// type traversal when t.HasShape() is false; and (2) shape types can't appear inside
// a named type, except for the type args of a generic type. So, the traversal will
// always stop before we have to deal with recursive types.
func getShapes(t *types.Type, listp *[]*types.Type) {
if !t.HasShape() {
return
}
if t.IsShape() {
*listp = append(*listp, t)
return
}
if t.Sym() != nil {
// A named type can't have shapes in it, except for type args of a
// generic type. We will have to deal with this differently once we
// alloc local types in generic functions (#47631).
for _, rparam := range t.RParams() {
getShapes(rparam, listp)
}
return
}
switch t.Kind() {
case types.TARRAY, types.TPTR, types.TSLICE, types.TCHAN:
getShapes(t.Elem(), listp)
case types.TSTRUCT:
for _, f := range t.FieldSlice() {
getShapes(f.Type, listp)
}
case types.TFUNC:
for _, f := range t.Recvs().FieldSlice() {
getShapes(f.Type, listp)
}
for _, f := range t.Params().FieldSlice() {
getShapes(f.Type, listp)
}
for _, f := range t.Results().FieldSlice() {
getShapes(f.Type, listp)
}
for _, f := range t.TParams().FieldSlice() {
getShapes(f.Type, listp)
}
case types.TINTER:
for _, f := range t.Methods().Slice() {
getShapes(f.Type, listp)
}
case types.TMAP:
getShapes(t.Key(), listp)
getShapes(t.Elem(), listp)
default:
panic(fmt.Sprintf("Bad type in getShapes: %v", t.Kind()))
}
}
// Shapify takes a concrete type and a type param index, and returns a GCshape type that can
// be used in place of the input type and still generate identical code.
// No methods are added - all methods calls directly on a shape should
// be done by converting to an interface using the dictionary.
//
// For now, we only consider two types to have the same shape, if they have exactly
// the same underlying type or they are both pointer types.
//
// tparam is the associated typeparam - it must be TTYPEPARAM type. If there is a
// structural type for the associated type param (not common), then a pointer type t
// is mapped to its underlying type, rather than being merged with other pointers.
//
// Shape types are also distinguished by the index of the type in a type param/arg
// list. We need to do this so we can distinguish and substitute properly for two
// type params in the same function that have the same shape for a particular
// instantiation.
func Shapify(t *types.Type, index int, tparam *types.Type) *types.Type {
assert(!t.IsShape())
if t.HasShape() {
// We are sometimes dealing with types from a shape instantiation
// that were constructed from existing shape types, so t may
// sometimes have shape types inside it. In that case, we find all
// those shape types with getShapes() and replace them with their
// underlying type.
//
// If we don't do this, we may create extra unneeded shape types that
// have these other shape types embedded in them. This may lead to
// generating extra shape instantiations, and a mismatch between the
// instantiations that we used in generating dictionaries and the
// instantations that are actually called. (#51303).
list := []*types.Type{}
getShapes(t, &list)
list2 := make([]*types.Type, len(list))
for i, shape := range list {
list2[i] = shape.Underlying()
}
ts := Tsubster{
Tparams: list,
Targs: list2,
}
t = ts.Typ(t)
}
// Map all types with the same underlying type to the same shape.
u := t.Underlying()
// All pointers have the same shape.
// TODO: Make unsafe.Pointer the same shape as normal pointers.
// Note: pointers to arrays are special because of slice-to-array-pointer
// conversions. See issue 49295.
if u.Kind() == types.TPTR && u.Elem().Kind() != types.TARRAY &&
tparam.Bound().StructuralType() == nil && !u.Elem().NotInHeap() {
u = types.Types[types.TUINT8].PtrTo()
}
submap := shapeMap[index]
if submap == nil {
submap = map[*types.Type]*types.Type{}
shapeMap[index] = submap
}
if s := submap[u]; s != nil {
return s
}
// LinkString specifies the type uniquely, but has no spaces.
nm := fmt.Sprintf("%s_%d", u.LinkString(), index)
sym := types.ShapePkg.Lookup(nm)
if sym.Def != nil {
// Use any existing type with the same name
submap[u] = sym.Def.Type()
return submap[u]
}
name := ir.NewDeclNameAt(u.Pos(), ir.OTYPE, sym)
s := types.NewNamed(name)
sym.Def = name
s.SetUnderlying(u)
s.SetIsShape(true)
s.SetHasShape(true)
types.CalcSize(s)
name.SetType(s)
name.SetTypecheck(1)
submap[u] = s
return s
}
var shapeMap = map[int]map[*types.Type]*types.Type{}
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