src/cmd/compile/internal/typecheck/dcl.go - toolchain/go - Git at Google

 // 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 (
 	"fmt"
 	"internal/types/errors"
 	"sync"

 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 )

 var DeclContext ir.Class = ir.PEXTERN // PEXTERN/PAUTO

 func DeclFunc(sym *types.Sym, recv *ir.Field, params, results []*ir.Field) *ir.Func {
 	fn := ir.NewFunc(base.Pos)
 	fn.Nname = ir.NewNameAt(base.Pos, sym)
 	fn.Nname.Func = fn
 	fn.Nname.Defn = fn
 	ir.MarkFunc(fn.Nname)
 	StartFuncBody(fn)

 	var recv1 *types.Field
 	if recv != nil {
 		recv1 = declareParam(ir.PPARAM, -1, recv)
 	}

 	typ := types.NewSignature(recv1, declareParams(ir.PPARAM, params), declareParams(ir.PPARAMOUT, results))
 	checkdupfields("argument", typ.Recvs().FieldSlice(), typ.Params().FieldSlice(), typ.Results().FieldSlice())
 	fn.Nname.SetType(typ)
 	fn.Nname.SetTypecheck(1)

 	return fn
 }

 // Declare records that Node n declares symbol n.Sym in the specified
 // declaration context.
 func Declare(n *ir.Name, ctxt ir.Class) {
 	if ir.IsBlank(n) {
 		return
 	}

 	s := n.Sym()

 	// kludgy: TypecheckAllowed means we're past parsing. Eg reflectdata.methodWrapper may declare out of package names later.
 	if !inimport && !TypecheckAllowed && s.Pkg != types.LocalPkg {
 		base.ErrorfAt(n.Pos(), 0, "cannot declare name %v", s)
 	}

 	if ctxt == ir.PEXTERN {
 		if s.Name == "init" {
 			base.ErrorfAt(n.Pos(), errors.InvalidInitDecl, "cannot declare init - must be func")
 		}
 		if s.Name == "main" && s.Pkg.Name == "main" {
 			base.ErrorfAt(n.Pos(), errors.InvalidMainDecl, "cannot declare main - must be func")
 		}
 		Target.Externs = append(Target.Externs, n)
 		s.Def = n
 	} else {
 		if ir.CurFunc == nil && ctxt == ir.PAUTO {
 			base.Pos = n.Pos()
 			base.Fatalf("automatic outside function")
 		}
 		if ir.CurFunc != nil && ctxt != ir.PFUNC && n.Op() == ir.ONAME {
 			ir.CurFunc.Dcl = append(ir.CurFunc.Dcl, n)
 		}
 		n.Curfn = ir.CurFunc
 	}

 	if ctxt == ir.PAUTO {
 		n.SetFrameOffset(0)
 	}

 	n.Class = ctxt
 	if ctxt == ir.PFUNC {
 		n.Sym().SetFunc(true)
 	}

 	autoexport(n, ctxt)
 }

 // Export marks n for export (or reexport).
 func Export(n *ir.Name) {
 	if n.Sym().OnExportList() {
 		return
 	}
 	n.Sym().SetOnExportList(true)

 	if base.Flag.E != 0 {
 		fmt.Printf("export symbol %v\n", n.Sym())
 	}

 	Target.Exports = append(Target.Exports, n)
 }

 // declare the function proper
 // and declare the arguments.
 // called in extern-declaration context
 // returns in auto-declaration context.
 func StartFuncBody(fn *ir.Func) {
 	// change the declaration context from extern to auto
 	funcStack = append(funcStack, funcStackEnt{ir.CurFunc, DeclContext})
 	ir.CurFunc = fn
 	DeclContext = ir.PAUTO
 }

 // finish the body.
 // called in auto-declaration context.
 // returns in extern-declaration context.
 func FinishFuncBody() {
 	// change the declaration context from auto to previous context
 	var e funcStackEnt
 	funcStack, e = funcStack[:len(funcStack)-1], funcStack[len(funcStack)-1]
 	ir.CurFunc, DeclContext = e.curfn, e.dclcontext
 }

 func CheckFuncStack() {
 	if len(funcStack) != 0 {
 		base.Fatalf("funcStack is non-empty: %v", len(funcStack))
 	}
 }

 func autoexport(n *ir.Name, ctxt ir.Class) {
 	if n.Sym().Pkg != types.LocalPkg {
 		return
 	}
 	if (ctxt != ir.PEXTERN && ctxt != ir.PFUNC) || DeclContext != ir.PEXTERN {
 		return
 	}
 	if n.Type() != nil && n.Type().IsKind(types.TFUNC) && ir.IsMethod(n) {
 		return
 	}

 	if types.IsExported(n.Sym().Name) || n.Sym().Name == "init" {
 		Export(n)
 	}
 	if base.Flag.AsmHdr != "" && !n.Sym().Asm() {
 		n.Sym().SetAsm(true)
 		Target.Asms = append(Target.Asms, n)
 	}
 }

 // checkdupfields emits errors for duplicately named fields or methods in
 // a list of struct or interface types.
 func checkdupfields(what string, fss ...[]*types.Field) {
 	seen := make(map[*types.Sym]bool)
 	for _, fs := range fss {
 		for _, f := range fs {
 			if f.Sym == nil || f.Sym.IsBlank() {
 				continue
 			}
 			if seen[f.Sym] {
 				base.ErrorfAt(f.Pos, errors.DuplicateFieldAndMethod, "duplicate %s %s", what, f.Sym.Name)
 				continue
 			}
 			seen[f.Sym] = true
 		}
 	}
 }

 // structs, functions, and methods.
 // they don't belong here, but where do they belong?
 func checkembeddedtype(t *types.Type) {
 	if t == nil {
 		return
 	}

 	if t.Sym() == nil && t.IsPtr() {
 		t = t.Elem()
 		if t.IsInterface() {
 			base.Errorf("embedded type cannot be a pointer to interface")
 		}
 	}

 	if t.IsPtr() || t.IsUnsafePtr() {
 		base.Errorf("embedded type cannot be a pointer")
 	} else if t.Kind() == types.TFORW && !t.ForwardType().Embedlineno.IsKnown() {
 		t.ForwardType().Embedlineno = base.Pos
 	}
 }

 var funcStack []funcStackEnt // stack of previous values of ir.CurFunc/DeclContext

 type funcStackEnt struct {
 	curfn      *ir.Func
 	dclcontext ir.Class
 }

 func declareParams(ctxt ir.Class, l []*ir.Field) []*types.Field {
 	fields := make([]*types.Field, len(l))
 	for i, n := range l {
 		fields[i] = declareParam(ctxt, i, n)
 	}
 	return fields
 }

 func declareParam(ctxt ir.Class, i int, param *ir.Field) *types.Field {
 	f := types.NewField(param.Pos, param.Sym, param.Type)
 	f.SetIsDDD(param.IsDDD)

 	sym := param.Sym
 	if ctxt == ir.PPARAMOUT {
 		if sym == nil {
 			// Name so that escape analysis can track it. ~r stands for 'result'.
 			sym = LookupNum("~r", i)
 		} else if sym.IsBlank() {
 			// Give it a name so we can assign to it during return. ~b stands for 'blank'.
 			// The name must be different from ~r above because if you have
 			//	func f() (_ int)
 			//	func g() int
 			// f is allowed to use a plain 'return' with no arguments, while g is not.
 			// So the two cases must be distinguished.
 			sym = LookupNum("~b", i)
 		}
 	}

 	if sym != nil {
 		name := ir.NewNameAt(param.Pos, sym)
 		name.SetType(f.Type)
 		name.SetTypecheck(1)
 		Declare(name, ctxt)

 		f.Nname = name
 	}

 	return f
 }

 func Temp(t *types.Type) *ir.Name {
 	return TempAt(base.Pos, ir.CurFunc, t)
 }

 // make a new Node off the books.
 func TempAt(pos src.XPos, curfn *ir.Func, t *types.Type) *ir.Name {
 	if curfn == nil {
 		base.Fatalf("no curfn for TempAt")
 	}
 	if curfn.Op() == ir.OCLOSURE {
 		ir.Dump("TempAt", curfn)
 		base.Fatalf("adding TempAt to wrong closure function")
 	}
 	if t == nil {
 		base.Fatalf("TempAt called with nil type")
 	}
 	if t.Kind() == types.TFUNC && t.Recv() != nil {
 		base.Fatalf("misuse of method type: %v", t)
 	}

 	s := &types.Sym{
 		Name: autotmpname(len(curfn.Dcl)),
 		Pkg:  types.LocalPkg,
 	}
 	n := ir.NewNameAt(pos, s)
 	s.Def = n
 	n.SetType(t)
 	n.SetTypecheck(1)
 	n.Class = ir.PAUTO
 	n.SetEsc(ir.EscNever)
 	n.Curfn = curfn
 	n.SetUsed(true)
 	n.SetAutoTemp(true)
 	curfn.Dcl = append(curfn.Dcl, n)

 	types.CalcSize(t)

 	return n
 }

 var (
 	autotmpnamesmu sync.Mutex
 	autotmpnames   []string
 )

 // autotmpname returns the name for an autotmp variable numbered n.
 func autotmpname(n int) string {
 	autotmpnamesmu.Lock()
 	defer autotmpnamesmu.Unlock()

 	// Grow autotmpnames, if needed.
 	if n >= len(autotmpnames) {
 		autotmpnames = append(autotmpnames, make([]string, n+1-len(autotmpnames))...)
 		autotmpnames = autotmpnames[:cap(autotmpnames)]
 	}

 	s := autotmpnames[n]
 	if s == "" {
 		// Give each tmp a different name so that they can be registerized.
 		// Add a preceding . to avoid clashing with legal names.
 		prefix := ".autotmp_%d"

 		s = fmt.Sprintf(prefix, n)
 		autotmpnames[n] = s
 	}
 	return s
 }

 // f is method type, with receiver.
 // return function type, receiver as first argument (or not).
 func NewMethodType(sig *types.Type, recv *types.Type) *types.Type {
 	nrecvs := 0
 	if recv != nil {
 		nrecvs++
 	}

 	// TODO(mdempsky): Move this function to types.
 	// TODO(mdempsky): Preserve positions, names, and package from sig+recv.

 	params := make([]*types.Field, nrecvs+sig.Params().Fields().Len())
 	if recv != nil {
 		params[0] = types.NewField(base.Pos, nil, recv)
 	}
 	for i, param := range sig.Params().Fields().Slice() {
 		d := types.NewField(base.Pos, nil, param.Type)
 		d.SetIsDDD(param.IsDDD())
 		params[nrecvs+i] = d
 	}

 	results := make([]*types.Field, sig.Results().Fields().Len())
 	for i, t := range sig.Results().Fields().Slice() {
 		results[i] = types.NewField(base.Pos, nil, t.Type)
 	}

 	return types.NewSignature(nil, params, results)
 }
	// 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 (
	"fmt"
	"internal/types/errors"
	"sync"

	"cmd/compile/internal/base"
	"cmd/compile/internal/ir"
	"cmd/compile/internal/types"
	"cmd/internal/src"
	)

	var DeclContext ir.Class = ir.PEXTERN // PEXTERN/PAUTO

	func DeclFunc(sym types.Sym, recv ir.Field, params, results []ir.Field) ir.Func {
	fn := ir.NewFunc(base.Pos)
	fn.Nname = ir.NewNameAt(base.Pos, sym)
	fn.Nname.Func = fn
	fn.Nname.Defn = fn
	ir.MarkFunc(fn.Nname)
	StartFuncBody(fn)

	var recv1 *types.Field
	if recv != nil {
	recv1 = declareParam(ir.PPARAM, -1, recv)
	}

	typ := types.NewSignature(recv1, declareParams(ir.PPARAM, params), declareParams(ir.PPARAMOUT, results))
	checkdupfields("argument", typ.Recvs().FieldSlice(), typ.Params().FieldSlice(), typ.Results().FieldSlice())
	fn.Nname.SetType(typ)
	fn.Nname.SetTypecheck(1)

	return fn
	}

	// Declare records that Node n declares symbol n.Sym in the specified
	// declaration context.
	func Declare(n *ir.Name, ctxt ir.Class) {
	if ir.IsBlank(n) {
	return
	}

	s := n.Sym()

	// kludgy: TypecheckAllowed means we're past parsing. Eg reflectdata.methodWrapper may declare out of package names later.
	if !inimport && !TypecheckAllowed && s.Pkg != types.LocalPkg {
	base.ErrorfAt(n.Pos(), 0, "cannot declare name %v", s)
	}

	if ctxt == ir.PEXTERN {
	if s.Name == "init" {
	base.ErrorfAt(n.Pos(), errors.InvalidInitDecl, "cannot declare init - must be func")
	}
	if s.Name == "main" && s.Pkg.Name == "main" {
	base.ErrorfAt(n.Pos(), errors.InvalidMainDecl, "cannot declare main - must be func")
	}
	Target.Externs = append(Target.Externs, n)
	s.Def = n
	} else {
	if ir.CurFunc == nil && ctxt == ir.PAUTO {
	base.Pos = n.Pos()
	base.Fatalf("automatic outside function")
	}
	if ir.CurFunc != nil && ctxt != ir.PFUNC && n.Op() == ir.ONAME {
	ir.CurFunc.Dcl = append(ir.CurFunc.Dcl, n)
	}
	n.Curfn = ir.CurFunc
	}

	if ctxt == ir.PAUTO {
	n.SetFrameOffset(0)
	}

	n.Class = ctxt
	if ctxt == ir.PFUNC {
	n.Sym().SetFunc(true)
	}

	autoexport(n, ctxt)
	}

	// Export marks n for export (or reexport).
	func Export(n *ir.Name) {
	if n.Sym().OnExportList() {
	return
	}
	n.Sym().SetOnExportList(true)

	if base.Flag.E != 0 {
	fmt.Printf("export symbol %v\n", n.Sym())
	}

	Target.Exports = append(Target.Exports, n)
	}

	// declare the function proper
	// and declare the arguments.
	// called in extern-declaration context
	// returns in auto-declaration context.
	func StartFuncBody(fn *ir.Func) {
	// change the declaration context from extern to auto
	funcStack = append(funcStack, funcStackEnt{ir.CurFunc, DeclContext})
	ir.CurFunc = fn
	DeclContext = ir.PAUTO
	}

	// finish the body.
	// called in auto-declaration context.
	// returns in extern-declaration context.
	func FinishFuncBody() {
	// change the declaration context from auto to previous context
	var e funcStackEnt
	funcStack, e = funcStack[:len(funcStack)-1], funcStack[len(funcStack)-1]
	ir.CurFunc, DeclContext = e.curfn, e.dclcontext
	}

	func CheckFuncStack() {
	if len(funcStack) != 0 {
	base.Fatalf("funcStack is non-empty: %v", len(funcStack))
	}
	}

	func autoexport(n *ir.Name, ctxt ir.Class) {
	if n.Sym().Pkg != types.LocalPkg {
	return
	}
	if (ctxt != ir.PEXTERN && ctxt != ir.PFUNC) \|\| DeclContext != ir.PEXTERN {
	return
	}
	if n.Type() != nil && n.Type().IsKind(types.TFUNC) && ir.IsMethod(n) {
	return
	}

	if types.IsExported(n.Sym().Name) \|\| n.Sym().Name == "init" {
	Export(n)
	}
	if base.Flag.AsmHdr != "" && !n.Sym().Asm() {
	n.Sym().SetAsm(true)
	Target.Asms = append(Target.Asms, n)
	}
	}

	// checkdupfields emits errors for duplicately named fields or methods in
	// a list of struct or interface types.
	func checkdupfields(what string, fss ...[]*types.Field) {
	seen := make(map[*types.Sym]bool)
	for _, fs := range fss {
	for _, f := range fs {
	if f.Sym == nil \|\| f.Sym.IsBlank() {
	continue
	}
	if seen[f.Sym] {
	base.ErrorfAt(f.Pos, errors.DuplicateFieldAndMethod, "duplicate %s %s", what, f.Sym.Name)
	continue
	}
	seen[f.Sym] = true
	}
	}
	}

	// structs, functions, and methods.
	// they don't belong here, but where do they belong?
	func checkembeddedtype(t *types.Type) {
	if t == nil {
	return
	}

	if t.Sym() == nil && t.IsPtr() {
	t = t.Elem()
	if t.IsInterface() {
	base.Errorf("embedded type cannot be a pointer to interface")
	}
	}

	if t.IsPtr() \|\| t.IsUnsafePtr() {
	base.Errorf("embedded type cannot be a pointer")
	} else if t.Kind() == types.TFORW && !t.ForwardType().Embedlineno.IsKnown() {
	t.ForwardType().Embedlineno = base.Pos
	}
	}

	var funcStack []funcStackEnt // stack of previous values of ir.CurFunc/DeclContext

	type funcStackEnt struct {
	curfn *ir.Func
	dclcontext ir.Class
	}

	func declareParams(ctxt ir.Class, l []ir.Field) []types.Field {
	fields := make([]*types.Field, len(l))
	for i, n := range l {
	fields[i] = declareParam(ctxt, i, n)
	}
	return fields
	}

	func declareParam(ctxt ir.Class, i int, param ir.Field) types.Field {
	f := types.NewField(param.Pos, param.Sym, param.Type)
	f.SetIsDDD(param.IsDDD)

	sym := param.Sym
	if ctxt == ir.PPARAMOUT {
	if sym == nil {
	// Name so that escape analysis can track it. ~r stands for 'result'.
	sym = LookupNum("~r", i)
	} else if sym.IsBlank() {
	// Give it a name so we can assign to it during return. ~b stands for 'blank'.
	// The name must be different from ~r above because if you have
	// func f() (_ int)
	// func g() int
	// f is allowed to use a plain 'return' with no arguments, while g is not.
	// So the two cases must be distinguished.
	sym = LookupNum("~b", i)
	}
	}

	if sym != nil {
	name := ir.NewNameAt(param.Pos, sym)
	name.SetType(f.Type)
	name.SetTypecheck(1)
	Declare(name, ctxt)

	f.Nname = name
	}

	return f
	}

	func Temp(t types.Type) ir.Name {
	return TempAt(base.Pos, ir.CurFunc, t)
	}

	// make a new Node off the books.
	func TempAt(pos src.XPos, curfn ir.Func, t types.Type) *ir.Name {
	if curfn == nil {
	base.Fatalf("no curfn for TempAt")
	}
	if curfn.Op() == ir.OCLOSURE {
	ir.Dump("TempAt", curfn)
	base.Fatalf("adding TempAt to wrong closure function")
	}
	if t == nil {
	base.Fatalf("TempAt called with nil type")
	}
	if t.Kind() == types.TFUNC && t.Recv() != nil {
	base.Fatalf("misuse of method type: %v", t)
	}

	s := &types.Sym{
	Name: autotmpname(len(curfn.Dcl)),
	Pkg: types.LocalPkg,
	}
	n := ir.NewNameAt(pos, s)
	s.Def = n
	n.SetType(t)
	n.SetTypecheck(1)
	n.Class = ir.PAUTO
	n.SetEsc(ir.EscNever)
	n.Curfn = curfn
	n.SetUsed(true)
	n.SetAutoTemp(true)
	curfn.Dcl = append(curfn.Dcl, n)

	types.CalcSize(t)

	return n
	}

	var (
	autotmpnamesmu sync.Mutex
	autotmpnames []string
	)

	// autotmpname returns the name for an autotmp variable numbered n.
	func autotmpname(n int) string {
	autotmpnamesmu.Lock()
	defer autotmpnamesmu.Unlock()

	// Grow autotmpnames, if needed.
	if n >= len(autotmpnames) {
	autotmpnames = append(autotmpnames, make([]string, n+1-len(autotmpnames))...)
	autotmpnames = autotmpnames[:cap(autotmpnames)]
	}

	s := autotmpnames[n]
	if s == "" {
	// Give each tmp a different name so that they can be registerized.
	// Add a preceding . to avoid clashing with legal names.
	prefix := ".autotmp_%d"

	s = fmt.Sprintf(prefix, n)
	autotmpnames[n] = s
	}
	return s
	}

	// f is method type, with receiver.
	// return function type, receiver as first argument (or not).
	func NewMethodType(sig types.Type, recv types.Type) *types.Type {
	nrecvs := 0
	if recv != nil {
	nrecvs++
	}

	// TODO(mdempsky): Move this function to types.
	// TODO(mdempsky): Preserve positions, names, and package from sig+recv.

	params := make([]*types.Field, nrecvs+sig.Params().Fields().Len())
	if recv != nil {
	params[0] = types.NewField(base.Pos, nil, recv)
	}
	for i, param := range sig.Params().Fields().Slice() {
	d := types.NewField(base.Pos, nil, param.Type)
	d.SetIsDDD(param.IsDDD())
	params[nrecvs+i] = d
	}

	results := make([]*types.Field, sig.Results().Fields().Len())
	for i, t := range sig.Results().Fields().Slice() {
	results[i] = types.NewField(base.Pos, nil, t.Type)
	}

	return types.NewSignature(nil, params, results)
	}