Golang程序
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2098行
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47.66 KB
// 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 gc
import (
"cmd/compile/internal/types"
"cmd/internal/objabi"
"cmd/internal/src"
"crypto/md5"
"encoding/binary"
"fmt"
"os"
"runtime/debug"
"sort"
"strconv"
"strings"
"sync"
"unicode"
"unicode/utf8"
)
type Error struct {
pos src.XPos
msg string
}
var errors []Error
var (
largeStackFramesMu sync.Mutex // protects largeStackFrames
largeStackFrames []src.XPos // positions of functions whose stack frames are too large (rare)
)
func errorexit() {
flusherrors()
if outfile != "" {
os.Remove(outfile)
}
os.Exit(2)
}
func adderrorname(n *Node) {
if n.Op != ODOT {
return
}
old := fmt.Sprintf("%v: undefined: %v\n", n.Line(), n.Left)
if len(errors) > 0 && errors[len(errors)-1].pos.Line() == n.Pos.Line() && errors[len(errors)-1].msg == old {
errors[len(errors)-1].msg = fmt.Sprintf("%v: undefined: %v in %v\n", n.Line(), n.Left, n)
}
}
func adderr(pos src.XPos, format string, args ...interface{}) {
errors = append(errors, Error{
pos: pos,
msg: fmt.Sprintf("%v: %s\n", linestr(pos), fmt.Sprintf(format, args...)),
})
}
// byPos sorts errors by source position.
type byPos []Error
func (x byPos) Len() int { return len(x) }
func (x byPos) Less(i, j int) bool { return x[i].pos.Before(x[j].pos) }
func (x byPos) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
// flusherrors sorts errors seen so far by line number, prints them to stdout,
// and empties the errors array.
func flusherrors() {
Ctxt.Bso.Flush()
if len(errors) == 0 {
return
}
sort.Stable(byPos(errors))
for i := 0; i < len(errors); i++ {
if i == 0 || errors[i].msg != errors[i-1].msg {
fmt.Printf("%s", errors[i].msg)
}
}
errors = errors[:0]
}
func hcrash() {
if Debug['h'] != 0 {
flusherrors()
if outfile != "" {
os.Remove(outfile)
}
var x *int
*x = 0
}
}
func linestr(pos src.XPos) string {
return Ctxt.OutermostPos(pos).Format(Debug['C'] == 0, Debug['L'] == 1)
}
// lasterror keeps track of the most recently issued error.
// It is used to avoid multiple error messages on the same
// line.
var lasterror struct {
syntax src.XPos // source position of last syntax error
other src.XPos // source position of last non-syntax error
msg string // error message of last non-syntax error
}
// sameline reports whether two positions a, b are on the same line.
func sameline(a, b src.XPos) bool {
p := Ctxt.PosTable.Pos(a)
q := Ctxt.PosTable.Pos(b)
return p.Base() == q.Base() && p.Line() == q.Line()
}
func yyerrorl(pos src.XPos, format string, args ...interface{}) {
msg := fmt.Sprintf(format, args...)
if strings.HasPrefix(msg, "syntax error") {
nsyntaxerrors++
// only one syntax error per line, no matter what error
if sameline(lasterror.syntax, pos) {
return
}
lasterror.syntax = pos
} else {
// only one of multiple equal non-syntax errors per line
// (flusherrors shows only one of them, so we filter them
// here as best as we can (they may not appear in order)
// so that we don't count them here and exit early, and
// then have nothing to show for.)
if sameline(lasterror.other, pos) && lasterror.msg == msg {
return
}
lasterror.other = pos
lasterror.msg = msg
}
adderr(pos, "%s", msg)
hcrash()
nerrors++
if nsavederrors+nerrors >= 10 && Debug['e'] == 0 {
flusherrors()
fmt.Printf("%v: too many errors\n", linestr(pos))
errorexit()
}
}
func yyerror(format string, args ...interface{}) {
yyerrorl(lineno, format, args...)
}
func Warn(fmt_ string, args ...interface{}) {
adderr(lineno, fmt_, args...)
hcrash()
}
func Warnl(line src.XPos, fmt_ string, args ...interface{}) {
adderr(line, fmt_, args...)
if Debug['m'] != 0 {
flusherrors()
}
}
func Fatalf(fmt_ string, args ...interface{}) {
flusherrors()
if Debug_panic != 0 || nsavederrors+nerrors == 0 {
fmt.Printf("%v: internal compiler error: ", linestr(lineno))
fmt.Printf(fmt_, args...)
fmt.Printf("\n")
// If this is a released compiler version, ask for a bug report.
if strings.HasPrefix(objabi.Version, "go") {
fmt.Printf("\n")
fmt.Printf("Please file a bug report including a short program that triggers the error.\n")
fmt.Printf("https://golang.org/issue/new\n")
} else {
// Not a release; dump a stack trace, too.
fmt.Println()
os.Stdout.Write(debug.Stack())
fmt.Println()
}
}
hcrash()
errorexit()
}
func setlineno(n *Node) src.XPos {
lno := lineno
if n != nil {
switch n.Op {
case ONAME, OPACK:
break
case OLITERAL, OTYPE:
if n.Sym != nil {
break
}
fallthrough
default:
lineno = n.Pos
if !lineno.IsKnown() {
if Debug['K'] != 0 {
Warn("setlineno: unknown position (line 0)")
}
lineno = lno
}
}
}
return lno
}
func lookup(name string) *types.Sym {
return localpkg.Lookup(name)
}
// lookupN looks up the symbol starting with prefix and ending with
// the decimal n. If prefix is too long, lookupN panics.
func lookupN(prefix string, n int) *types.Sym {
var buf [20]byte // plenty long enough for all current users
copy(buf[:], prefix)
b := strconv.AppendInt(buf[:len(prefix)], int64(n), 10)
return localpkg.LookupBytes(b)
}
// autolabel generates a new Name node for use with
// an automatically generated label.
// prefix is a short mnemonic (e.g. ".s" for switch)
// to help with debugging.
// It should begin with "." to avoid conflicts with
// user labels.
func autolabel(prefix string) *Node {
if prefix[0] != '.' {
Fatalf("autolabel prefix must start with '.', have %q", prefix)
}
fn := Curfn
if Curfn == nil {
Fatalf("autolabel outside function")
}
n := fn.Func.Label
fn.Func.Label++
return newname(lookupN(prefix, int(n)))
}
func restrictlookup(name string, pkg *types.Pkg) *types.Sym {
if !exportname(name) && pkg != localpkg {
yyerror("cannot refer to unexported name %s.%s", pkg.Name, name)
}
return pkg.Lookup(name)
}
// find all the exported symbols in package opkg
// and make them available in the current package
func importdot(opkg *types.Pkg, pack *Node) {
n := 0
for _, s := range opkg.Syms {
if s.Def == nil {
continue
}
if !exportname(s.Name) || strings.ContainsRune(s.Name, 0xb7) { // 0xb7 = center dot
continue
}
s1 := lookup(s.Name)
if s1.Def != nil {
pkgerror := fmt.Sprintf("during import %q", opkg.Path)
redeclare(s1, pkgerror)
continue
}
s1.Def = s.Def
s1.Block = s.Block
if asNode(s1.Def).Name == nil {
Dump("s1def", asNode(s1.Def))
Fatalf("missing Name")
}
asNode(s1.Def).Name.Pack = pack
s1.Origpkg = opkg
n++
}
if n == 0 {
// can't possibly be used - there were no symbols
yyerrorl(pack.Pos, "imported and not used: %q", opkg.Path)
}
}
func nod(op Op, nleft, nright *Node) *Node {
return nodl(lineno, op, nleft, nright)
}
func nodl(pos src.XPos, op Op, nleft, nright *Node) *Node {
var n *Node
switch op {
case OCLOSURE, ODCLFUNC:
var x struct {
Node
Func
}
n = &x.Node
n.Func = &x.Func
case ONAME:
Fatalf("use newname instead")
case OLABEL, OPACK:
var x struct {
Node
Name
}
n = &x.Node
n.Name = &x.Name
default:
n = new(Node)
}
n.Op = op
n.Left = nleft
n.Right = nright
n.Pos = pos
n.Xoffset = BADWIDTH
n.Orig = n
return n
}
// newname returns a new ONAME Node associated with symbol s.
func newname(s *types.Sym) *Node {
n := newnamel(lineno, s)
n.Name.Curfn = Curfn
return n
}
// newname returns a new ONAME Node associated with symbol s at position pos.
// The caller is responsible for setting n.Name.Curfn.
func newnamel(pos src.XPos, s *types.Sym) *Node {
if s == nil {
Fatalf("newnamel nil")
}
var x struct {
Node
Name
Param
}
n := &x.Node
n.Name = &x.Name
n.Name.Param = &x.Param
n.Op = ONAME
n.Pos = pos
n.Orig = n
n.Sym = s
n.SetAddable(true)
return n
}
// nodSym makes a Node with Op op and with the Left field set to left
// and the Sym field set to sym. This is for ODOT and friends.
func nodSym(op Op, left *Node, sym *types.Sym) *Node {
n := nod(op, left, nil)
n.Sym = sym
return n
}
func saveorignode(n *Node) {
if n.Orig != nil {
return
}
norig := nod(n.Op, nil, nil)
*norig = *n
n.Orig = norig
}
// methcmp sorts by symbol, then by package path for unexported symbols.
type methcmp []*types.Field
func (x methcmp) Len() int { return len(x) }
func (x methcmp) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
func (x methcmp) Less(i, j int) bool {
a := x[i]
b := x[j]
if a.Sym == nil && b.Sym == nil {
return false
}
if a.Sym == nil {
return true
}
if b.Sym == nil {
return false
}
if a.Sym.Name != b.Sym.Name {
return a.Sym.Name < b.Sym.Name
}
if !exportname(a.Sym.Name) {
if a.Sym.Pkg.Path != b.Sym.Pkg.Path {
return a.Sym.Pkg.Path < b.Sym.Pkg.Path
}
}
return false
}
func nodintconst(v int64) *Node {
c := nod(OLITERAL, nil, nil)
c.SetAddable(true)
c.SetVal(Val{new(Mpint)})
c.Val().U.(*Mpint).SetInt64(v)
c.Type = types.Types[TIDEAL]
return c
}
func nodfltconst(v *Mpflt) *Node {
c := nod(OLITERAL, nil, nil)
c.SetAddable(true)
c.SetVal(Val{newMpflt()})
c.Val().U.(*Mpflt).Set(v)
c.Type = types.Types[TIDEAL]
return c
}
func nodconst(n *Node, t *types.Type, v int64) {
*n = Node{}
n.Op = OLITERAL
n.SetAddable(true)
n.SetVal(Val{new(Mpint)})
n.Val().U.(*Mpint).SetInt64(v)
n.Type = t
if t.IsFloat() {
Fatalf("nodconst: bad type %v", t)
}
}
func nodnil() *Node {
c := nodintconst(0)
c.SetVal(Val{new(NilVal)})
c.Type = types.Types[TNIL]
return c
}
func nodbool(b bool) *Node {
c := nodintconst(0)
c.SetVal(Val{b})
c.Type = types.Idealbool
return c
}
func nodstr(s string) *Node {
return nodlit(Val{s})
}
// treecopy recursively copies n, with the exception of
// ONAME, OLITERAL, OTYPE, and non-iota ONONAME leaves.
// Copies of iota ONONAME nodes are assigned the current
// value of iota_. If pos.IsKnown(), it sets the source
// position of newly allocated nodes to pos.
func treecopy(n *Node, pos src.XPos) *Node {
if n == nil {
return nil
}
switch n.Op {
default:
m := *n
m.Orig = &m
m.Left = treecopy(n.Left, pos)
m.Right = treecopy(n.Right, pos)
m.List.Set(listtreecopy(n.List.Slice(), pos))
if pos.IsKnown() {
m.Pos = pos
}
if m.Name != nil && n.Op != ODCLFIELD {
Dump("treecopy", n)
Fatalf("treecopy Name")
}
return &m
case OPACK:
// OPACK nodes are never valid in const value declarations,
// but allow them like any other declared symbol to avoid
// crashing (golang.org/issue/11361).
fallthrough
case ONAME, ONONAME, OLITERAL, OTYPE:
return n
}
}
// isnil reports whether n represents the universal untyped zero value "nil".
func isnil(n *Node) bool {
// Check n.Orig because constant propagation may produce typed nil constants,
// which don't exist in the Go spec.
return Isconst(n.Orig, CTNIL)
}
func isptrto(t *types.Type, et types.EType) bool {
if t == nil {
return false
}
if !t.IsPtr() {
return false
}
t = t.Elem()
if t == nil {
return false
}
if t.Etype != et {
return false
}
return true
}
func isblank(n *Node) bool {
if n == nil {
return false
}
return n.Sym.IsBlank()
}
// methtype returns the underlying type, if any,
// that owns methods with receiver parameter t.
// The result is either a named type or an anonymous struct.
func methtype(t *types.Type) *types.Type {
if t == nil {
return nil
}
// Strip away pointer if it's there.
if t.IsPtr() {
if t.Sym != nil {
return nil
}
t = t.Elem()
if t == nil {
return nil
}
}
// Must be a named type or anonymous struct.
if t.Sym == nil && !t.IsStruct() {
return nil
}
// Check types.
if issimple[t.Etype] {
return t
}
switch t.Etype {
case TARRAY, TCHAN, TFUNC, TMAP, TSLICE, TSTRING, TSTRUCT:
return t
}
return nil
}
// eqtype reports whether t1 and t2 are identical, following the spec rules.
//
// Any cyclic type must go through a named type, and if one is
// named, it is only identical to the other if they are the same
// pointer (t1 == t2), so there's no chance of chasing cycles
// ad infinitum, so no need for a depth counter.
func eqtype(t1, t2 *types.Type) bool {
return eqtype1(t1, t2, true, nil)
}
// eqtypeIgnoreTags is like eqtype but it ignores struct tags for struct identity.
func eqtypeIgnoreTags(t1, t2 *types.Type) bool {
return eqtype1(t1, t2, false, nil)
}
type typePair struct {
t1 *types.Type
t2 *types.Type
}
func eqtype1(t1, t2 *types.Type, cmpTags bool, assumedEqual map[typePair]struct{}) bool {
if t1 == t2 {
return true
}
if t1 == nil || t2 == nil || t1.Etype != t2.Etype || t1.Broke() || t2.Broke() {
return false
}
if t1.Sym != nil || t2.Sym != nil {
// Special case: we keep byte/uint8 and rune/int32
// separate for error messages. Treat them as equal.
switch t1.Etype {
case TUINT8:
return (t1 == types.Types[TUINT8] || t1 == types.Bytetype) && (t2 == types.Types[TUINT8] || t2 == types.Bytetype)
case TINT32:
return (t1 == types.Types[TINT32] || t1 == types.Runetype) && (t2 == types.Types[TINT32] || t2 == types.Runetype)
default:
return false
}
}
if assumedEqual == nil {
assumedEqual = make(map[typePair]struct{})
} else if _, ok := assumedEqual[typePair{t1, t2}]; ok {
return true
}
assumedEqual[typePair{t1, t2}] = struct{}{}
switch t1.Etype {
case TINTER:
if t1.NumFields() != t2.NumFields() {
return false
}
for i, f1 := range t1.FieldSlice() {
f2 := t2.Field(i)
if f1.Sym != f2.Sym || !eqtype1(f1.Type, f2.Type, cmpTags, assumedEqual) {
return false
}
}
return true
case TSTRUCT:
if t1.NumFields() != t2.NumFields() {
return false
}
for i, f1 := range t1.FieldSlice() {
f2 := t2.Field(i)
if f1.Sym != f2.Sym || f1.Embedded != f2.Embedded || !eqtype1(f1.Type, f2.Type, cmpTags, assumedEqual) {
return false
}
if cmpTags && f1.Note != f2.Note {
return false
}
}
return true
case TFUNC:
// Check parameters and result parameters for type equality.
// We intentionally ignore receiver parameters for type
// equality, because they're never relevant.
for _, f := range types.ParamsResults {
// Loop over fields in structs, ignoring argument names.
fs1, fs2 := f(t1).FieldSlice(), f(t2).FieldSlice()
if len(fs1) != len(fs2) {
return false
}
for i, f1 := range fs1 {
f2 := fs2[i]
if f1.Isddd() != f2.Isddd() || !eqtype1(f1.Type, f2.Type, cmpTags, assumedEqual) {
return false
}
}
}
return true
case TARRAY:
if t1.NumElem() != t2.NumElem() {
return false
}
case TCHAN:
if t1.ChanDir() != t2.ChanDir() {
return false
}
case TMAP:
if !eqtype1(t1.Key(), t2.Key(), cmpTags, assumedEqual) {
return false
}
return eqtype1(t1.Val(), t2.Val(), cmpTags, assumedEqual)
}
return eqtype1(t1.Elem(), t2.Elem(), cmpTags, assumedEqual)
}
// Are t1 and t2 equal struct types when field names are ignored?
// For deciding whether the result struct from g can be copied
// directly when compiling f(g()).
func eqtypenoname(t1 *types.Type, t2 *types.Type) bool {
if t1 == nil || t2 == nil || !t1.IsStruct() || !t2.IsStruct() {
return false
}
if t1.NumFields() != t2.NumFields() {
return false
}
for i, f1 := range t1.FieldSlice() {
f2 := t2.Field(i)
if !eqtype(f1.Type, f2.Type) {
return false
}
}
return true
}
// Is type src assignment compatible to type dst?
// If so, return op code to use in conversion.
// If not, return 0.
func assignop(src *types.Type, dst *types.Type, why *string) Op {
if why != nil {
*why = ""
}
// TODO(rsc,lvd): This behaves poorly in the presence of inlining.
// https://golang.org/issue/2795
if safemode && !inimport && src != nil && src.Etype == TUNSAFEPTR {
yyerror("cannot use unsafe.Pointer")
errorexit()
}
if src == dst {
return OCONVNOP
}
if src == nil || dst == nil || src.Etype == TFORW || dst.Etype == TFORW || src.Orig == nil || dst.Orig == nil {
return 0
}
// 1. src type is identical to dst.
if eqtype(src, dst) {
return OCONVNOP
}
// 2. src and dst have identical underlying types
// and either src or dst is not a named type or
// both are empty interface types.
// 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 eqtype(src.Orig, dst.Orig) {
if src.IsEmptyInterface() {
// Conversion between two empty interfaces
// requires no code.
return 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 OCONVNOP
}
}
// 3. dst is an interface type and src implements dst.
if dst.IsInterface() && src.Etype != TNIL {
var missing, have *types.Field
var ptr int
if implements(src, dst, &missing, &have, &ptr) {
return OCONVIFACE
}
// we'll have complained about this method anyway, suppress spurious messages.
if have != nil && have.Sym == missing.Sym && (have.Type.Broke() || missing.Type.Broke()) {
return OCONVIFACE
}
if why != nil {
if isptrto(src, 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%0S\n\t\twant %v%0S", 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%0S\n\t\twant %v%0S", 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 0
}
if isptrto(dst, TINTER) {
if why != nil {
*why = fmt.Sprintf(":\n\t%v is pointer to interface, not interface", dst)
}
return 0
}
if src.IsInterface() && dst.Etype != TBLANK {
var missing, have *types.Field
var ptr int
if why != nil && implements(dst, src, &missing, &have, &ptr) {
*why = ": need type assertion"
}
return 0
}
// 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 eqtype(src.Elem(), dst.Elem()) && (src.Sym == nil || dst.Sym == nil) {
return OCONVNOP
}
}
// 5. src is the predeclared identifier nil and dst is a nillable type.
if src.Etype == TNIL {
switch dst.Etype {
case TPTR32,
TPTR64,
TFUNC,
TMAP,
TCHAN,
TINTER,
TSLICE:
return OCONVNOP
}
}
// 6. rule about untyped constants - already converted by defaultlit.
// 7. Any typed value can be assigned to the blank identifier.
if dst.Etype == TBLANK {
return OCONVNOP
}
return 0
}
// 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 0.
func convertop(src *types.Type, dst *types.Type, why *string) Op {
if why != nil {
*why = ""
}
if src == dst {
return OCONVNOP
}
if src == nil || dst == nil {
return 0
}
// Conversions from regular to go:notinheap are not allowed
// (unless it's unsafe.Pointer). This is a runtime-specific
// rule.
if src.IsPtr() && dst.IsPtr() && dst.Elem().NotInHeap() && !src.Elem().NotInHeap() {
if why != nil {
*why = fmt.Sprintf(":\n\t%v is go:notinheap, but %v is not", dst.Elem(), src.Elem())
}
return 0
}
// 1. src can be assigned to dst.
op := assignop(src, dst, why)
if op != 0 {
return op
}
// 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 0
}
if why != nil {
*why = ""
}
// 2. Ignoring struct tags, src and dst have identical underlying types.
if eqtypeIgnoreTags(src.Orig, dst.Orig) {
return 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 eqtypeIgnoreTags(src.Elem().Orig, dst.Elem().Orig) {
return OCONVNOP
}
}
// 4. src and dst are both integer or floating point types.
if (src.IsInteger() || src.IsFloat()) && (dst.IsInteger() || dst.IsFloat()) {
if simtype[src.Etype] == simtype[dst.Etype] {
return OCONVNOP
}
return OCONV
}
// 5. src and dst are both complex types.
if src.IsComplex() && dst.IsComplex() {
if simtype[src.Etype] == simtype[dst.Etype] {
return OCONVNOP
}
return OCONV
}
// 6. src is an integer or has type []byte or []rune
// and dst is a string type.
if src.IsInteger() && dst.IsString() {
return ORUNESTR
}
if src.IsSlice() && dst.IsString() {
if src.Elem().Etype == types.Bytetype.Etype {
return OARRAYBYTESTR
}
if src.Elem().Etype == types.Runetype.Etype {
return OARRAYRUNESTR
}
}
// 7. src is a string and dst is []byte or []rune.
// String to slice.
if src.IsString() && dst.IsSlice() {
if dst.Elem().Etype == types.Bytetype.Etype {
return OSTRARRAYBYTE
}
if dst.Elem().Etype == types.Runetype.Etype {
return OSTRARRAYRUNE
}
}
// 8. src is a pointer or uintptr and dst is unsafe.Pointer.
if (src.IsPtr() || src.Etype == TUINTPTR) && dst.Etype == TUNSAFEPTR {
return OCONVNOP
}
// 9. src is unsafe.Pointer and dst is a pointer or uintptr.
if src.Etype == TUNSAFEPTR && (dst.IsPtr() || dst.Etype == TUINTPTR) {
return OCONVNOP
}
// 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.Etype == TMAP && dst.IsPtr() &&
src.MapType().Hmap == dst.Elem() {
return OCONVNOP
}
return 0
}
func assignconv(n *Node, t *types.Type, context string) *Node {
return assignconvfn(n, t, func() string { return context })
}
// Convert node n for assignment to type t.
func assignconvfn(n *Node, t *types.Type, context func() string) *Node {
if n == nil || n.Type == nil || n.Type.Broke() {
return n
}
if t.Etype == TBLANK && n.Type.Etype == TNIL {
yyerror("use of untyped nil")
}
old := n
od := old.Diag()
old.SetDiag(true) // silence errors about n; we'll issue one below
n = defaultlit(n, t)
old.SetDiag(od)
if t.Etype == TBLANK {
return n
}
// Convert ideal bool from comparison to plain bool
// if the next step is non-bool (like interface{}).
if n.Type == types.Idealbool && !t.IsBoolean() {
if n.Op == ONAME || n.Op == OLITERAL {
r := nod(OCONVNOP, n, nil)
r.Type = types.Types[TBOOL]
r.SetTypecheck(1)
r.SetImplicit(true)
n = r
}
}
if eqtype(n.Type, t) {
return n
}
var why string
op := assignop(n.Type, t, &why)
if op == 0 {
if !old.Diag() {
yyerror("cannot use %L as type %v in %s%s", n, t, context(), why)
}
op = OCONV
}
r := nod(op, n, nil)
r.Type = t
r.SetTypecheck(1)
r.SetImplicit(true)
r.Orig = n.Orig
return r
}
// IsMethod reports whether n is a method.
// n must be a function or a method.
func (n *Node) IsMethod() bool {
return n.Type.Recv() != nil
}
// SliceBounds returns n's slice bounds: low, high, and max in expr[low:high:max].
// n must be a slice expression. max is nil if n is a simple slice expression.
func (n *Node) SliceBounds() (low, high, max *Node) {
if n.List.Len() == 0 {
return nil, nil, nil
}
switch n.Op {
case OSLICE, OSLICEARR, OSLICESTR:
s := n.List.Slice()
return s[0], s[1], nil
case OSLICE3, OSLICE3ARR:
s := n.List.Slice()
return s[0], s[1], s[2]
}
Fatalf("SliceBounds op %v: %v", n.Op, n)
return nil, nil, nil
}
// SetSliceBounds sets n's slice bounds, where n is a slice expression.
// n must be a slice expression. If max is non-nil, n must be a full slice expression.
func (n *Node) SetSliceBounds(low, high, max *Node) {
switch n.Op {
case OSLICE, OSLICEARR, OSLICESTR:
if max != nil {
Fatalf("SetSliceBounds %v given three bounds", n.Op)
}
s := n.List.Slice()
if s == nil {
if low == nil && high == nil {
return
}
n.List.Set2(low, high)
return
}
s[0] = low
s[1] = high
return
case OSLICE3, OSLICE3ARR:
s := n.List.Slice()
if s == nil {
if low == nil && high == nil && max == nil {
return
}
n.List.Set3(low, high, max)
return
}
s[0] = low
s[1] = high
s[2] = max
return
}
Fatalf("SetSliceBounds op %v: %v", n.Op, n)
}
// IsSlice3 reports whether o is a slice3 op (OSLICE3, OSLICE3ARR).
// o must be a slicing op.
func (o Op) IsSlice3() bool {
switch o {
case OSLICE, OSLICEARR, OSLICESTR:
return false
case OSLICE3, OSLICE3ARR:
return true
}
Fatalf("IsSlice3 op %v", o)
return false
}
// labeledControl returns the control flow Node (for, switch, select)
// associated with the label n, if any.
func (n *Node) labeledControl() *Node {
if n.Op != OLABEL {
Fatalf("labeledControl %v", n.Op)
}
ctl := n.Name.Defn
if ctl == nil {
return nil
}
switch ctl.Op {
case OFOR, OFORUNTIL, OSWITCH, OSELECT:
return ctl
}
return nil
}
func syslook(name string) *Node {
s := Runtimepkg.Lookup(name)
if s == nil || s.Def == nil {
Fatalf("syslook: can't find runtime.%s", name)
}
return asNode(s.Def)
}
// typehash computes a hash value for type t to use in type switch statements.
func typehash(t *types.Type) uint32 {
p := t.LongString()
// Using MD5 is overkill, but reduces accidental collisions.
h := md5.Sum([]byte(p))
return binary.LittleEndian.Uint32(h[:4])
}
func frame(context int) {
if context != 0 {
fmt.Printf("--- external frame ---\n")
for _, n := range externdcl {
printframenode(n)
}
return
}
if Curfn != nil {
fmt.Printf("--- %v frame ---\n", Curfn.Func.Nname.Sym)
for _, ln := range Curfn.Func.Dcl {
printframenode(ln)
}
}
}
func printframenode(n *Node) {
w := int64(-1)
if n.Type != nil {
w = n.Type.Width
}
switch n.Op {
case ONAME:
fmt.Printf("%v %v G%d %v width=%d\n", n.Op, n.Sym, n.Name.Vargen, n.Type, w)
case OTYPE:
fmt.Printf("%v %v width=%d\n", n.Op, n.Type, w)
}
}
// updateHasCall checks whether expression n contains any function
// calls and sets the n.HasCall flag if so.
func updateHasCall(n *Node) {
if n == nil {
return
}
n.SetHasCall(calcHasCall(n))
}
func calcHasCall(n *Node) bool {
if n.Ninit.Len() != 0 {
// TODO(mdempsky): This seems overly conservative.
return true
}
switch n.Op {
case OLITERAL, ONAME, OTYPE:
if n.HasCall() {
Fatalf("OLITERAL/ONAME/OTYPE should never have calls: %+v", n)
}
return false
case OCALL, OCALLFUNC, OCALLMETH, OCALLINTER:
return true
case OANDAND, OOROR:
// hard with instrumented code
if instrumenting {
return true
}
case OINDEX, OSLICE, OSLICEARR, OSLICE3, OSLICE3ARR, OSLICESTR,
OIND, ODOTPTR, ODOTTYPE, ODIV, OMOD:
// These ops might panic, make sure they are done
// before we start marshaling args for a call. See issue 16760.
return true
// When using soft-float, these ops might be rewritten to function calls
// so we ensure they are evaluated first.
case OADD, OSUB, OMINUS:
if thearch.SoftFloat && (isFloat[n.Type.Etype] || isComplex[n.Type.Etype]) {
return true
}
case OLT, OEQ, ONE, OLE, OGE, OGT:
if thearch.SoftFloat && (isFloat[n.Left.Type.Etype] || isComplex[n.Left.Type.Etype]) {
return true
}
case OCONV:
if thearch.SoftFloat && ((isFloat[n.Type.Etype] || isComplex[n.Type.Etype]) || (isFloat[n.Left.Type.Etype] || isComplex[n.Left.Type.Etype])) {
return true
}
}
if n.Left != nil && n.Left.HasCall() {
return true
}
if n.Right != nil && n.Right.HasCall() {
return true
}
return false
}
func badtype(op Op, tl *types.Type, tr *types.Type) {
fmt_ := ""
if tl != nil {
fmt_ += fmt.Sprintf("\n\t%v", tl)
}
if tr != nil {
fmt_ += fmt.Sprintf("\n\t%v", tr)
}
// common mistake: *struct and *interface.
if tl != nil && tr != nil && tl.IsPtr() && tr.IsPtr() {
if tl.Elem().IsStruct() && tr.Elem().IsInterface() {
fmt_ += "\n\t(*struct vs *interface)"
} else if tl.Elem().IsInterface() && tr.Elem().IsStruct() {
fmt_ += "\n\t(*interface vs *struct)"
}
}
s := fmt_
yyerror("illegal types for operand: %v%s", op, s)
}
// brcom returns !(op).
// For example, brcom(==) is !=.
func brcom(op Op) Op {
switch op {
case OEQ:
return ONE
case ONE:
return OEQ
case OLT:
return OGE
case OGT:
return OLE
case OLE:
return OGT
case OGE:
return OLT
}
Fatalf("brcom: no com for %v\n", op)
return op
}
// brrev returns reverse(op).
// For example, Brrev(<) is >.
func brrev(op Op) Op {
switch op {
case OEQ:
return OEQ
case ONE:
return ONE
case OLT:
return OGT
case OGT:
return OLT
case OLE:
return OGE
case OGE:
return OLE
}
Fatalf("brrev: no rev for %v\n", op)
return op
}
// return side effect-free n, appending side effects to init.
// result is assignable if n is.
func safeexpr(n *Node, init *Nodes) *Node {
if n == nil {
return nil
}
if n.Ninit.Len() != 0 {
walkstmtlist(n.Ninit.Slice())
init.AppendNodes(&n.Ninit)
}
switch n.Op {
case ONAME, OLITERAL:
return n
case ODOT, OLEN, OCAP:
l := safeexpr(n.Left, init)
if l == n.Left {
return n
}
r := nod(OXXX, nil, nil)
*r = *n
r.Left = l
r = typecheck(r, Erv)
r = walkexpr(r, init)
return r
case ODOTPTR, OIND:
l := safeexpr(n.Left, init)
if l == n.Left {
return n
}
a := nod(OXXX, nil, nil)
*a = *n
a.Left = l
a = walkexpr(a, init)
return a
case OINDEX, OINDEXMAP:
l := safeexpr(n.Left, init)
r := safeexpr(n.Right, init)
if l == n.Left && r == n.Right {
return n
}
a := nod(OXXX, nil, nil)
*a = *n
a.Left = l
a.Right = r
a = walkexpr(a, init)
return a
case OSTRUCTLIT, OARRAYLIT, OSLICELIT:
if isStaticCompositeLiteral(n) {
return n
}
}
// make a copy; must not be used as an lvalue
if islvalue(n) {
Fatalf("missing lvalue case in safeexpr: %v", n)
}
return cheapexpr(n, init)
}
func copyexpr(n *Node, t *types.Type, init *Nodes) *Node {
l := temp(t)
a := nod(OAS, l, n)
a = typecheck(a, Etop)
a = walkexpr(a, init)
init.Append(a)
return l
}
// return side-effect free and cheap n, appending side effects to init.
// result may not be assignable.
func cheapexpr(n *Node, init *Nodes) *Node {
switch n.Op {
case ONAME, OLITERAL:
return n
}
return copyexpr(n, n.Type, init)
}
// 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
}
// 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)
// 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() {
for _, f := range u.Fields().Slice() {
if f.Sym == s || (ignorecase && f.Type.Etype == TFUNC && f.Type.Recv() != nil && strings.EqualFold(f.Sym.Name, s.Name)) {
if save != nil {
*save = f
}
c++
}
}
}
u = methtype(t)
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
}
// 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
}
for _, f := range u.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
}
// 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
}
}
}
// in T.field
// find missing fields that
// will give shortest unique addressing.
// modify the tree with missing type names.
func adddot(n *Node) *Node {
n.Left = typecheck(n.Left, Etype|Erv)
if n.Left.Diag() {
n.SetDiag(true)
}
t := n.Left.Type
if t == nil {
return n
}
if n.Left.Op == OTYPE {
return n
}
s := n.Sym
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-- {
n.Left = nodSym(ODOT, n.Left, path[c].field.Sym)
n.Left.SetImplicit(true)
}
case ambig:
yyerror("ambiguous selector %v", n)
n.Left = nil
}
return n
}
// code to help generate trampoline
// functions for methods on embedded
// subtypes.
// these are approx the same as
// the corresponding adddot routines
// except that they expect to be called
// with unique tasks and they return
// the actual methods.
type Symlink struct {
field *types.Field
followptr bool
}
var slist []Symlink
func expand0(t *types.Type, followptr bool) {
u := t
if u.IsPtr() {
followptr = true
u = u.Elem()
}
if u.IsInterface() {
for _, f := range u.Fields().Slice() {
if f.Sym.Uniq() {
continue
}
f.Sym.SetUniq(true)
slist = append(slist, Symlink{field: f, followptr: followptr})
}
return
}
u = methtype(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, followptr: followptr})
}
}
}
func expand1(t *types.Type, top, followptr bool) {
if t.Recur() {
return
}
t.SetRecur(true)
if !top {
expand0(t, followptr)
}
u := t
if u.IsPtr() {
followptr = true
u = u.Elem()
}
if u.IsStruct() || u.IsInterface() {
for _, f := range u.Fields().Slice() {
if f.Embedded == 0 {
continue
}
if f.Sym == nil {
continue
}
expand1(f.Type, false, followptr)
}
}
t.SetRecur(false)
}
func expandmeth(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, false)
// 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
if path, _ := dotpath(sl.field.Sym, t, &f, false); path == nil {
continue
}
// dotpath may have dug out arbitrary fields, we only want methods.
if f.Type.Etype != TFUNC || f.Type.Recv() == nil {
continue
}
// add it to the base type method list
f = f.Copy()
f.Embedded = 1 // needs a trampoline
if sl.followptr {
f.Embedded = 2
}
ms = append(ms, f)
}
for _, f := range t.Methods().Slice() {
f.Sym.SetUniq(false)
}
ms = append(ms, t.Methods().Slice()...)
t.AllMethods().Set(ms)
}
// Given funarg struct list, return list of ODCLFIELD Node fn args.
func structargs(tl *types.Type, mustname bool) []*Node {
var args []*Node
gen := 0
for _, t := range tl.Fields().Slice() {
var n *Node
if mustname && (t.Sym == nil || t.Sym.Name == "_") {
// invent a name so that we can refer to it in the trampoline
buf := fmt.Sprintf(".anon%d", gen)
gen++
n = newname(lookup(buf))
} else if t.Sym != nil {
n = newname(t.Sym)
}
a := nod(ODCLFIELD, n, typenod(t.Type))
a.SetIsddd(t.Isddd())
if n != nil {
n.SetIsddd(t.Isddd())
}
args = append(args, a)
}
return args
}
// 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, iface bool) {
if false && Debug['r'] != 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 != localpkg {
return
}
lineno = autogeneratedPos
dclcontext = PEXTERN
types.Markdcl()
this := namedfield(".this", rcvr)
this.Left.Name.Param.Ntype = this.Right
in := structargs(method.Type.Params(), true)
out := structargs(method.Type.Results(), false)
t := nod(OTFUNC, nil, nil)
l := []*Node{this}
if iface && rcvr.Width < int64(Widthptr) {
// Building method for interface table and receiver
// is smaller than the single pointer-sized word
// that the interface call will pass in.
// Add a dummy padding argument after the
// receiver to make up the difference.
tpad := types.NewArray(types.Types[TUINT8], int64(Widthptr)-rcvr.Width)
pad := namedfield(".pad", tpad)
l = append(l, pad)
}
t.List.Set(append(l, in...))
t.Rlist.Set(out)
fn := dclfunc(newnam, t)
fn.Func.SetDupok(true)
fn.Func.Nname.Sym.SetExported(true) // prevent export; see closure.go
// arg list
var args []*Node
isddd := false
for _, n := range in {
args = append(args, n.Left)
isddd = n.Left.Isddd()
}
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 := nod(OIF, nil, nil)
n.Left = nod(OEQ, this.Left, nodnil())
call := nod(OCALL, syslook("panicwrap"), nil)
n.Nbody.Set1(call)
fn.Nbody.Append(n)
}
dot := adddot(nodSym(OXDOT, this.Left, 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 !instrumenting && rcvr.IsPtr() && methodrcvr.IsPtr() && method.Embedded != 0 && !isifacemethod(method.Type) && !(thearch.LinkArch.Name == "ppc64le" && Ctxt.Flag_dynlink) {
// generate tail call: adjust pointer receiver and jump to embedded method.
dot = dot.Left // skip final .M
// TODO(mdempsky): Remove dependency on dotlist.
if !dotlist[0].field.Type.IsPtr() {
dot = nod(OADDR, dot, nil)
}
as := nod(OAS, this.Left, nod(OCONVNOP, dot, nil))
as.Right.Type = rcvr
fn.Nbody.Append(as)
fn.Nbody.Append(nodSym(ORETJMP, nil, methodsym(method.Sym, methodrcvr, false)))
// When tail-calling, we can't use a frame pointer.
fn.Func.SetNoFramePointer(true)
} else {
fn.Func.SetWrapper(true) // ignore frame for panic+recover matching
call := nod(OCALL, dot, nil)
call.List.Set(args)
call.SetIsddd(isddd)
if method.Type.NumResults() > 0 {
n := nod(ORETURN, nil, nil)
n.List.Set1(call)
call = n
}
fn.Nbody.Append(call)
}
if false && Debug['r'] != 0 {
dumplist("genwrapper body", fn.Nbody)
}
funcbody()
Curfn = fn
types.Popdcl()
if debug_dclstack != 0 {
testdclstack()
}
// wrappers where T is anonymous (struct or interface) can be duplicated.
if rcvr.IsStruct() || rcvr.IsInterface() || rcvr.IsPtr() && rcvr.Elem().IsStruct() {
fn.Func.SetDupok(true)
}
fn = typecheck(fn, Etop)
typecheckslice(fn.Nbody.Slice(), Etop)
inlcalls(fn)
escAnalyze([]*Node{fn}, false)
Curfn = nil
funccompile(fn)
}
func hashmem(t *types.Type) *Node {
sym := Runtimepkg.Lookup("memhash")
n := newname(sym)
n.SetClass(PFUNC)
tfn := nod(OTFUNC, nil, nil)
tfn.List.Append(anonfield(types.NewPtr(t)))
tfn.List.Append(anonfield(types.Types[TUINTPTR]))
tfn.List.Append(anonfield(types.Types[TUINTPTR]))
tfn.Rlist.Append(anonfield(types.Types[TUINTPTR]))
tfn = typecheck(tfn, Etype)
n.Type = tfn.Type
return n
}
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 {
yyerror("%v.%v is ambiguous", t, s)
}
return nil, false
}
for _, d := range path {
if d.field.Type.IsPtr() {
followptr = true
break
}
}
if m.Type.Etype != TFUNC || m.Type.Recv() == nil {
yyerror("%v.%v is a field, not a method", t, s)
return nil, followptr
}
return m, followptr
}
func implements(t, iface *types.Type, m, samename **types.Field, ptr *int) bool {
t0 := t
if t == nil {
return false
}
// if this is too slow,
// could sort these first
// and then do one loop.
if t.IsInterface() {
Outer:
for _, im := range iface.Fields().Slice() {
for _, tm := range t.Fields().Slice() {
if tm.Sym == im.Sym {
if eqtype(tm.Type, im.Type) {
continue Outer
}
*m = im
*samename = tm
*ptr = 0
return false
}
}
*m = im
*samename = nil
*ptr = 0
return false
}
return true
}
t = methtype(t)
if t != nil {
expandmeth(t)
}
for _, im := range iface.Fields().Slice() {
if im.Broke() {
continue
}
tm, followptr := ifacelookdot(im.Sym, t, false)
if tm == nil || tm.Nointerface() || !eqtype(tm.Type, im.Type) {
if tm == nil {
tm, followptr = ifacelookdot(im.Sym, t, true)
}
*m = im
*samename = tm
*ptr = 0
return false
}
// if pointer receiver in method,
// the method does not exist for value types.
rcvr := tm.Type.Recv().Type
if rcvr.IsPtr() && !t0.IsPtr() && !followptr && !isifacemethod(tm.Type) {
if false && Debug['r'] != 0 {
yyerror("interface pointer mismatch")
}
*m = im
*samename = nil
*ptr = 1
return false
}
}
// We're going to emit an OCONVIFACE.
// Call itabname so that (t, iface)
// gets added to itabs early, which allows
// us to de-virtualize calls through this
// type/interface pair later. See peekitabs in reflect.go
if isdirectiface(t0) && !iface.IsEmptyInterface() {
itabname(t0, iface)
}
return true
}
func listtreecopy(l []*Node, pos src.XPos) []*Node {
var out []*Node
for _, n := range l {
out = append(out, treecopy(n, pos))
}
return out
}
func liststmt(l []*Node) *Node {
n := nod(OBLOCK, nil, nil)
n.List.Set(l)
if len(l) != 0 {
n.Pos = l[0].Pos
}
return n
}
func (l Nodes) asblock() *Node {
n := nod(OBLOCK, nil, nil)
n.List = l
if l.Len() != 0 {
n.Pos = l.First().Pos
}
return n
}
func ngotype(n *Node) *types.Sym {
if n.Type != nil {
return typenamesym(n.Type)
}
return nil
}
// The result of addinit MUST be assigned back to n, e.g.
// n.Left = addinit(n.Left, init)
func addinit(n *Node, init []*Node) *Node {
if len(init) == 0 {
return n
}
if n.mayBeShared() {
// Introduce OCONVNOP to hold init list.
n = nod(OCONVNOP, n, nil)
n.Type = n.Left.Type
n.SetTypecheck(1)
}
n.Ninit.Prepend(init...)
n.SetHasCall(true)
return n
}
// The linker uses the magic symbol prefixes "go." and "type."
// Avoid potential confusion between import paths and symbols
// by rejecting these reserved imports for now. Also, people
// "can do weird things in GOPATH and we'd prefer they didn't
// do _that_ weird thing" (per rsc). See also #4257.
var reservedimports = []string{
"go",
"type",
}
func isbadimport(path string, allowSpace bool) bool {
if strings.Contains(path, "\x00") {
yyerror("import path contains NUL")
return true
}
for _, ri := range reservedimports {
if path == ri {
yyerror("import path %q is reserved and cannot be used", path)
return true
}
}
for _, r := range path {
if r == utf8.RuneError {
yyerror("import path contains invalid UTF-8 sequence: %q", path)
return true
}
if r < 0x20 || r == 0x7f {
yyerror("import path contains control character: %q", path)
return true
}
if r == '\\' {
yyerror("import path contains backslash; use slash: %q", path)
return true
}
if !allowSpace && unicode.IsSpace(r) {
yyerror("import path contains space character: %q", path)
return true
}
if strings.ContainsRune("!\"#$%&'()*,:;<=>?[]^`{|}", r) {
yyerror("import path contains invalid character '%c': %q", r, path)
return true
}
}
return false
}
func checknil(x *Node, init *Nodes) {
x = walkexpr(x, nil) // caller has not done this yet
if x.Type.IsInterface() {
x = nod(OITAB, x, nil)
x = typecheck(x, Erv)
}
n := nod(OCHECKNIL, x, nil)
n.SetTypecheck(1)
init.Append(n)
}
// Can this type be stored directly in an interface word?
// Yes, if the representation is a single pointer.
func isdirectiface(t *types.Type) bool {
if t.Broke() {
return false
}
switch t.Etype {
case TPTR32,
TPTR64,
TCHAN,
TMAP,
TFUNC,
TUNSAFEPTR:
return true
case TARRAY:
// Array of 1 direct iface type can be direct.
return t.NumElem() == 1 && isdirectiface(t.Elem())
case TSTRUCT:
// Struct with 1 field of direct iface type can be direct.
return t.NumFields() == 1 && isdirectiface(t.Field(0).Type)
}
return false
}
// itabType loads the _type field from a runtime.itab struct.
func itabType(itab *Node) *Node {
typ := nodSym(ODOTPTR, itab, nil)
typ.Type = types.NewPtr(types.Types[TUINT8])
typ.SetTypecheck(1)
typ.Xoffset = int64(Widthptr) // offset of _type in runtime.itab
typ.SetBounded(true) // guaranteed not to fault
return typ
}
// ifaceData loads the data field from an interface.
// The concrete type must be known to have type t.
// It follows the pointer if !isdirectiface(t).
func ifaceData(n *Node, t *types.Type) *Node {
ptr := nodSym(OIDATA, n, nil)
if isdirectiface(t) {
ptr.Type = t
ptr.SetTypecheck(1)
return ptr
}
ptr.Type = types.NewPtr(t)
ptr.SetBounded(true)
ptr.SetTypecheck(1)
ind := nod(OIND, ptr, nil)
ind.Type = t
ind.SetTypecheck(1)
return ind
}