src/cmd/compile/internal/noder/decl.go - go - Git at Google

 // Copyright 2021 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 noder

 import (
 	"go/constant"

 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/syntax"
 	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/compile/internal/types2"
 )

 // TODO(mdempsky): Skip blank declarations? Probably only safe
 // for declarations without pragmas.

 func (g *irgen) decls(res *ir.Nodes, decls []syntax.Decl) {
 	for _, decl := range decls {
 		switch decl := decl.(type) {
 		case *syntax.ConstDecl:
 			g.constDecl(res, decl)
 		case *syntax.FuncDecl:
 			g.funcDecl(res, decl)
 		case *syntax.TypeDecl:
 			if ir.CurFunc == nil {
 				continue // already handled in irgen.generate
 			}
 			g.typeDecl(res, decl)
 		case *syntax.VarDecl:
 			g.varDecl(res, decl)
 		default:
 			g.unhandled("declaration", decl)
 		}
 	}
 }

 func (g *irgen) importDecl(p *noder, decl *syntax.ImportDecl) {
 	g.pragmaFlags(decl.Pragma, 0)

 	// Get the imported package's path, as resolved already by types2
 	// and gcimporter. This is the same path as would be computed by
 	// parseImportPath.
 	switch pkgNameOf(g.info, decl).Imported().Path() {
 	case "unsafe":
 		p.importedUnsafe = true
 	case "embed":
 		p.importedEmbed = true
 	}
 }

 // pkgNameOf returns the PkgName associated with the given ImportDecl.
 func pkgNameOf(info *types2.Info, decl *syntax.ImportDecl) *types2.PkgName {
 	if name := decl.LocalPkgName; name != nil {
 		return info.Defs[name].(*types2.PkgName)
 	}
 	return info.Implicits[decl].(*types2.PkgName)
 }

 func (g *irgen) constDecl(out *ir.Nodes, decl *syntax.ConstDecl) {
 	g.pragmaFlags(decl.Pragma, 0)

 	for _, name := range decl.NameList {
 		name, obj := g.def(name)

 		// For untyped numeric constants, make sure the value
 		// representation matches what the rest of the
 		// compiler (really just iexport) expects.
 		// TODO(mdempsky): Revisit after #43891 is resolved.
 		val := obj.(*types2.Const).Val()
 		switch name.Type() {
 		case types.UntypedInt, types.UntypedRune:
 			val = constant.ToInt(val)
 		case types.UntypedFloat:
 			val = constant.ToFloat(val)
 		case types.UntypedComplex:
 			val = constant.ToComplex(val)
 		}
 		name.SetVal(val)

 		out.Append(ir.NewDecl(g.pos(decl), ir.ODCLCONST, name))
 	}
 }

 func (g *irgen) funcDecl(out *ir.Nodes, decl *syntax.FuncDecl) {
 	fn := ir.NewFunc(g.pos(decl))
 	fn.Nname, _ = g.def(decl.Name)
 	fn.Nname.Func = fn
 	fn.Nname.Defn = fn

 	fn.Pragma = g.pragmaFlags(decl.Pragma, funcPragmas)
 	if fn.Pragma&ir.Systemstack != 0 && fn.Pragma&ir.Nosplit != 0 {
 		base.ErrorfAt(fn.Pos(), "go:nosplit and go:systemstack cannot be combined")
 	}
 	if fn.Pragma&ir.Nointerface != 0 {
 		// Propagate //go:nointerface from Func.Pragma to Field.Nointerface.
 		// This is a bit roundabout, but this is the earliest point where we've
 		// processed the function's pragma flags, and we've also already created
 		// the Fields to represent the receiver's method set.
 		if recv := fn.Type().Recv(); recv != nil {
 			typ := types.ReceiverBaseType(recv.Type)
 			if typ.OrigSym() != nil {
 				// For a generic method, we mark the methods on the
 				// base generic type, since those are the methods
 				// that will be stenciled.
 				typ = typ.OrigSym().Def.Type()
 			}
 			meth := typecheck.Lookdot1(fn, typecheck.Lookup(decl.Name.Value), typ, typ.Methods(), 0)
 			meth.SetNointerface(true)
 		}
 	}

 	if decl.Body != nil && fn.Pragma&ir.Noescape != 0 {
 		base.ErrorfAt(fn.Pos(), "can only use //go:noescape with external func implementations")
 	}

 	if decl.Name.Value == "init" && decl.Recv == nil {
 		g.target.Inits = append(g.target.Inits, fn)
 	}

 	g.later(func() {
 		if fn.Type().HasTParam() {
 			g.topFuncIsGeneric = true
 		}
 		g.funcBody(fn, decl.Recv, decl.Type, decl.Body)
 		g.topFuncIsGeneric = false
 		if fn.Type().HasTParam() && fn.Body != nil {
 			// Set pointers to the dcls/body of a generic function/method in
 			// the Inl struct, so it is marked for export, is available for
 			// stenciling, and works with Inline_Flood().
 			fn.Inl = &ir.Inline{
 				Cost: 1,
 				Dcl:  fn.Dcl,
 				Body: fn.Body,
 			}
 		}

 		out.Append(fn)
 	})
 }

 func (g *irgen) typeDecl(out *ir.Nodes, decl *syntax.TypeDecl) {
 	if decl.Alias {
 		name, _ := g.def(decl.Name)
 		g.pragmaFlags(decl.Pragma, 0)
 		assert(name.Alias()) // should be set by irgen.obj

 		out.Append(ir.NewDecl(g.pos(decl), ir.ODCLTYPE, name))
 		return
 	}

 	// Prevent size calculations until we set the underlying type.
 	types.DeferCheckSize()

 	name, obj := g.def(decl.Name)
 	ntyp, otyp := name.Type(), obj.Type()
 	if ir.CurFunc != nil {
 		ntyp.SetVargen()
 	}

 	pragmas := g.pragmaFlags(decl.Pragma, typePragmas)
 	name.SetPragma(pragmas) // TODO(mdempsky): Is this still needed?

 	if pragmas&ir.NotInHeap != 0 {
 		ntyp.SetNotInHeap(true)
 	}

 	// We need to use g.typeExpr(decl.Type) here to ensure that for
 	// chained, defined-type declarations like:
 	//
 	//	type T U
 	//
 	//	//go:notinheap
 	//	type U struct { … }
 	//
 	// we mark both T and U as NotInHeap. If we instead used just
 	// g.typ(otyp.Underlying()), then we'd instead set T's underlying
 	// type directly to the struct type (which is not marked NotInHeap)
 	// and fail to mark T as NotInHeap.
 	//
 	// Also, we rely here on Type.SetUnderlying allowing passing a
 	// defined type and handling forward references like from T to U
 	// above. Contrast with go/types's Named.SetUnderlying, which
 	// disallows this.
 	//
 	// [mdempsky: Subtleties like these are why I always vehemently
 	// object to new type pragmas.]
 	ntyp.SetUnderlying(g.typeExpr(decl.Type))

 	tparams := otyp.(*types2.Named).TypeParams()
 	if n := tparams.Len(); n > 0 {
 		rparams := make([]*types.Type, n)
 		for i := range rparams {
 			rparams[i] = g.typ(tparams.At(i))
 		}
 		// This will set hasTParam flag if any rparams are not concrete types.
 		ntyp.SetRParams(rparams)
 	}
 	types.ResumeCheckSize()

 	if otyp, ok := otyp.(*types2.Named); ok && otyp.NumMethods() != 0 {
 		methods := make([]*types.Field, otyp.NumMethods())
 		for i := range methods {
 			m := otyp.Method(i)
 			meth := g.obj(m)
 			methods[i] = types.NewField(meth.Pos(), g.selector(m), meth.Type())
 			methods[i].Nname = meth
 		}
 		ntyp.Methods().Set(methods)
 	}

 	out.Append(ir.NewDecl(g.pos(decl), ir.ODCLTYPE, name))
 }

 func (g *irgen) varDecl(out *ir.Nodes, decl *syntax.VarDecl) {
 	pos := g.pos(decl)
 	names := make([]*ir.Name, len(decl.NameList))
 	for i, name := range decl.NameList {
 		names[i], _ = g.def(name)
 	}

 	if decl.Pragma != nil {
 		pragma := decl.Pragma.(*pragmas)
 		// TODO(mdempsky): Plumb noder.importedEmbed through to here.
 		varEmbed(g.makeXPos, names[0], decl, pragma, true)
 		g.reportUnused(pragma)
 	}

 	do := func() {
 		values := g.exprList(decl.Values)

 		var as2 *ir.AssignListStmt
 		if len(values) != 0 && len(names) != len(values) {
 			as2 = ir.NewAssignListStmt(pos, ir.OAS2, make([]ir.Node, len(names)), values)
 		}

 		for i, name := range names {
 			if ir.CurFunc != nil {
 				out.Append(ir.NewDecl(pos, ir.ODCL, name))
 			}
 			if as2 != nil {
 				as2.Lhs[i] = name
 				name.Defn = as2
 			} else {
 				as := ir.NewAssignStmt(pos, name, nil)
 				if len(values) != 0 {
 					as.Y = values[i]
 					name.Defn = as
 				} else if ir.CurFunc == nil {
 					name.Defn = as
 				}
 				lhs := []ir.Node{as.X}
 				rhs := []ir.Node{}
 				if as.Y != nil {
 					rhs = []ir.Node{as.Y}
 				}
 				transformAssign(as, lhs, rhs)
 				as.X = lhs[0]
 				if as.Y != nil {
 					as.Y = rhs[0]
 				}
 				as.SetTypecheck(1)
 				out.Append(as)
 			}
 		}
 		if as2 != nil {
 			transformAssign(as2, as2.Lhs, as2.Rhs)
 			as2.SetTypecheck(1)
 			out.Append(as2)
 		}
 	}

 	// If we're within a function, we need to process the assignment
 	// part of the variable declaration right away. Otherwise, we leave
 	// it to be handled after all top-level declarations are processed.
 	if ir.CurFunc != nil {
 		do()
 	} else {
 		g.later(do)
 	}
 }

 // pragmaFlags returns any specified pragma flags included in allowed,
 // and reports errors about any other, unexpected pragmas.
 func (g *irgen) pragmaFlags(pragma syntax.Pragma, allowed ir.PragmaFlag) ir.PragmaFlag {
 	if pragma == nil {
 		return 0
 	}
 	p := pragma.(*pragmas)
 	present := p.Flag & allowed
 	p.Flag &^= allowed
 	g.reportUnused(p)
 	return present
 }

 // reportUnused reports errors about any unused pragmas.
 func (g *irgen) reportUnused(pragma *pragmas) {
 	for _, pos := range pragma.Pos {
 		if pos.Flag&pragma.Flag != 0 {
 			base.ErrorfAt(g.makeXPos(pos.Pos), "misplaced compiler directive")
 		}
 	}
 	if len(pragma.Embeds) > 0 {
 		for _, e := range pragma.Embeds {
 			base.ErrorfAt(g.makeXPos(e.Pos), "misplaced go:embed directive")
 		}
 	}
 }
	// Copyright 2021 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 noder

	import (
	"go/constant"

	"cmd/compile/internal/base"
	"cmd/compile/internal/ir"
	"cmd/compile/internal/syntax"
	"cmd/compile/internal/typecheck"
	"cmd/compile/internal/types"
	"cmd/compile/internal/types2"
	)

	// TODO(mdempsky): Skip blank declarations? Probably only safe
	// for declarations without pragmas.

	func (g irgen) decls(res ir.Nodes, decls []syntax.Decl) {
	for _, decl := range decls {
	switch decl := decl.(type) {
	case *syntax.ConstDecl:
	g.constDecl(res, decl)
	case *syntax.FuncDecl:
	g.funcDecl(res, decl)
	case *syntax.TypeDecl:
	if ir.CurFunc == nil {
	continue // already handled in irgen.generate
	}
	g.typeDecl(res, decl)
	case *syntax.VarDecl:
	g.varDecl(res, decl)
	default:
	g.unhandled("declaration", decl)
	}
	}
	}

	func (g irgen) importDecl(p noder, decl *syntax.ImportDecl) {
	g.pragmaFlags(decl.Pragma, 0)

	// Get the imported package's path, as resolved already by types2
	// and gcimporter. This is the same path as would be computed by
	// parseImportPath.
	switch pkgNameOf(g.info, decl).Imported().Path() {
	case "unsafe":
	p.importedUnsafe = true
	case "embed":
	p.importedEmbed = true
	}
	}

	// pkgNameOf returns the PkgName associated with the given ImportDecl.
	func pkgNameOf(info types2.Info, decl syntax.ImportDecl) *types2.PkgName {
	if name := decl.LocalPkgName; name != nil {
	return info.Defs[name].(*types2.PkgName)
	}
	return info.Implicits[decl].(*types2.PkgName)
	}

	func (g irgen) constDecl(out ir.Nodes, decl *syntax.ConstDecl) {
	g.pragmaFlags(decl.Pragma, 0)

	for _, name := range decl.NameList {
	name, obj := g.def(name)

	// For untyped numeric constants, make sure the value
	// representation matches what the rest of the
	// compiler (really just iexport) expects.
	// TODO(mdempsky): Revisit after #43891 is resolved.
	val := obj.(*types2.Const).Val()
	switch name.Type() {
	case types.UntypedInt, types.UntypedRune:
	val = constant.ToInt(val)
	case types.UntypedFloat:
	val = constant.ToFloat(val)
	case types.UntypedComplex:
	val = constant.ToComplex(val)
	}
	name.SetVal(val)

	out.Append(ir.NewDecl(g.pos(decl), ir.ODCLCONST, name))
	}
	}

	func (g irgen) funcDecl(out ir.Nodes, decl *syntax.FuncDecl) {
	fn := ir.NewFunc(g.pos(decl))
	fn.Nname, _ = g.def(decl.Name)
	fn.Nname.Func = fn
	fn.Nname.Defn = fn

	fn.Pragma = g.pragmaFlags(decl.Pragma, funcPragmas)
	if fn.Pragma&ir.Systemstack != 0 && fn.Pragma&ir.Nosplit != 0 {
	base.ErrorfAt(fn.Pos(), "go:nosplit and go:systemstack cannot be combined")
	}
	if fn.Pragma&ir.Nointerface != 0 {
	// Propagate //go:nointerface from Func.Pragma to Field.Nointerface.
	// This is a bit roundabout, but this is the earliest point where we've
	// processed the function's pragma flags, and we've also already created
	// the Fields to represent the receiver's method set.
	if recv := fn.Type().Recv(); recv != nil {
	typ := types.ReceiverBaseType(recv.Type)
	if typ.OrigSym() != nil {
	// For a generic method, we mark the methods on the
	// base generic type, since those are the methods
	// that will be stenciled.
	typ = typ.OrigSym().Def.Type()
	}
	meth := typecheck.Lookdot1(fn, typecheck.Lookup(decl.Name.Value), typ, typ.Methods(), 0)
	meth.SetNointerface(true)
	}
	}

	if decl.Body != nil && fn.Pragma&ir.Noescape != 0 {
	base.ErrorfAt(fn.Pos(), "can only use //go:noescape with external func implementations")
	}

	if decl.Name.Value == "init" && decl.Recv == nil {
	g.target.Inits = append(g.target.Inits, fn)
	}

	g.later(func() {
	if fn.Type().HasTParam() {
	g.topFuncIsGeneric = true
	}
	g.funcBody(fn, decl.Recv, decl.Type, decl.Body)
	g.topFuncIsGeneric = false
	if fn.Type().HasTParam() && fn.Body != nil {
	// Set pointers to the dcls/body of a generic function/method in
	// the Inl struct, so it is marked for export, is available for
	// stenciling, and works with Inline_Flood().
	fn.Inl = &ir.Inline{
	Cost: 1,
	Dcl: fn.Dcl,
	Body: fn.Body,
	}
	}

	out.Append(fn)
	})
	}

	func (g irgen) typeDecl(out ir.Nodes, decl *syntax.TypeDecl) {
	if decl.Alias {
	name, _ := g.def(decl.Name)
	g.pragmaFlags(decl.Pragma, 0)
	assert(name.Alias()) // should be set by irgen.obj

	out.Append(ir.NewDecl(g.pos(decl), ir.ODCLTYPE, name))
	return
	}

	// Prevent size calculations until we set the underlying type.
	types.DeferCheckSize()

	name, obj := g.def(decl.Name)
	ntyp, otyp := name.Type(), obj.Type()
	if ir.CurFunc != nil {
	ntyp.SetVargen()
	}

	pragmas := g.pragmaFlags(decl.Pragma, typePragmas)
	name.SetPragma(pragmas) // TODO(mdempsky): Is this still needed?

	if pragmas&ir.NotInHeap != 0 {
	ntyp.SetNotInHeap(true)
	}

	// We need to use g.typeExpr(decl.Type) here to ensure that for
	// chained, defined-type declarations like:
	//
	// type T U
	//
	// //go:notinheap
	// type U struct { … }
	//
	// we mark both T and U as NotInHeap. If we instead used just
	// g.typ(otyp.Underlying()), then we'd instead set T's underlying
	// type directly to the struct type (which is not marked NotInHeap)
	// and fail to mark T as NotInHeap.
	//
	// Also, we rely here on Type.SetUnderlying allowing passing a
	// defined type and handling forward references like from T to U
	// above. Contrast with go/types's Named.SetUnderlying, which
	// disallows this.
	//
	// [mdempsky: Subtleties like these are why I always vehemently
	// object to new type pragmas.]
	ntyp.SetUnderlying(g.typeExpr(decl.Type))

	tparams := otyp.(*types2.Named).TypeParams()
	if n := tparams.Len(); n > 0 {
	rparams := make([]*types.Type, n)
	for i := range rparams {
	rparams[i] = g.typ(tparams.At(i))
	}
	// This will set hasTParam flag if any rparams are not concrete types.
	ntyp.SetRParams(rparams)
	}
	types.ResumeCheckSize()

	if otyp, ok := otyp.(*types2.Named); ok && otyp.NumMethods() != 0 {
	methods := make([]*types.Field, otyp.NumMethods())
	for i := range methods {
	m := otyp.Method(i)
	meth := g.obj(m)
	methods[i] = types.NewField(meth.Pos(), g.selector(m), meth.Type())
	methods[i].Nname = meth
	}
	ntyp.Methods().Set(methods)
	}

	out.Append(ir.NewDecl(g.pos(decl), ir.ODCLTYPE, name))
	}

	func (g irgen) varDecl(out ir.Nodes, decl *syntax.VarDecl) {
	pos := g.pos(decl)
	names := make([]*ir.Name, len(decl.NameList))
	for i, name := range decl.NameList {
	names[i], _ = g.def(name)
	}

	if decl.Pragma != nil {
	pragma := decl.Pragma.(*pragmas)
	// TODO(mdempsky): Plumb noder.importedEmbed through to here.
	varEmbed(g.makeXPos, names[0], decl, pragma, true)
	g.reportUnused(pragma)
	}

	do := func() {
	values := g.exprList(decl.Values)

	var as2 *ir.AssignListStmt
	if len(values) != 0 && len(names) != len(values) {
	as2 = ir.NewAssignListStmt(pos, ir.OAS2, make([]ir.Node, len(names)), values)
	}

	for i, name := range names {
	if ir.CurFunc != nil {
	out.Append(ir.NewDecl(pos, ir.ODCL, name))
	}
	if as2 != nil {
	as2.Lhs[i] = name
	name.Defn = as2
	} else {
	as := ir.NewAssignStmt(pos, name, nil)
	if len(values) != 0 {
	as.Y = values[i]
	name.Defn = as
	} else if ir.CurFunc == nil {
	name.Defn = as
	}
	lhs := []ir.Node{as.X}
	rhs := []ir.Node{}
	if as.Y != nil {
	rhs = []ir.Node{as.Y}
	}
	transformAssign(as, lhs, rhs)
	as.X = lhs[0]
	if as.Y != nil {
	as.Y = rhs[0]
	}
	as.SetTypecheck(1)
	out.Append(as)
	}
	}
	if as2 != nil {
	transformAssign(as2, as2.Lhs, as2.Rhs)
	as2.SetTypecheck(1)
	out.Append(as2)
	}
	}

	// If we're within a function, we need to process the assignment
	// part of the variable declaration right away. Otherwise, we leave
	// it to be handled after all top-level declarations are processed.
	if ir.CurFunc != nil {
	do()
	} else {
	g.later(do)
	}
	}

	// pragmaFlags returns any specified pragma flags included in allowed,
	// and reports errors about any other, unexpected pragmas.
	func (g *irgen) pragmaFlags(pragma syntax.Pragma, allowed ir.PragmaFlag) ir.PragmaFlag {
	if pragma == nil {
	return 0
	}
	p := pragma.(*pragmas)
	present := p.Flag & allowed
	p.Flag &^= allowed
	g.reportUnused(p)
	return present
	}

	// reportUnused reports errors about any unused pragmas.
	func (g irgen) reportUnused(pragma pragmas) {
	for _, pos := range pragma.Pos {
	if pos.Flag&pragma.Flag != 0 {
	base.ErrorfAt(g.makeXPos(pos.Pos), "misplaced compiler directive")
	}
	}
	if len(pragma.Embeds) > 0 {
	for _, e := range pragma.Embeds {
	base.ErrorfAt(g.makeXPos(e.Pos), "misplaced go:embed directive")
	}
	}
	}