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go/src/cmd/compile/internal/gc/noder.go
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// Copyright 2016 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 ( | |
"fmt" | |
"os" | |
"path/filepath" | |
"runtime" | |
"strconv" | |
"strings" | |
"unicode/utf8" | |
"cmd/compile/internal/syntax" | |
"cmd/compile/internal/types" | |
"cmd/internal/obj" | |
"cmd/internal/objabi" | |
"cmd/internal/src" | |
) | |
// parseFiles concurrently parses files into *syntax.File structures. | |
// Each declaration in every *syntax.File is converted to a syntax tree | |
// and its root represented by *Node is appended to xtop. | |
// Returns the total count of parsed lines. | |
func parseFiles(filenames []string) uint { | |
noders := make([]*noder, 0, len(filenames)) | |
// Limit the number of simultaneously open files. | |
sem := make(chan struct{}, runtime.GOMAXPROCS(0)+10) | |
for _, filename := range filenames { | |
p := &noder{ | |
basemap: make(map[*syntax.PosBase]*src.PosBase), | |
err: make(chan syntax.Error), | |
} | |
noders = append(noders, p) | |
go func(filename string) { | |
sem <- struct{}{} | |
defer func() { <-sem }() | |
defer close(p.err) | |
base := syntax.NewFileBase(filename) | |
f, err := os.Open(filename) | |
if err != nil { | |
p.error(syntax.Error{Msg: err.Error()}) | |
return | |
} | |
defer f.Close() | |
p.file, _ = syntax.Parse(base, f, p.error, p.pragma, syntax.CheckBranches) // errors are tracked via p.error | |
}(filename) | |
} | |
var lines uint | |
for _, p := range noders { | |
for e := range p.err { | |
p.yyerrorpos(e.Pos, "%s", e.Msg) | |
} | |
p.node() | |
lines += p.file.Lines | |
p.file = nil // release memory | |
if nsyntaxerrors != 0 { | |
errorexit() | |
} | |
// Always run testdclstack here, even when debug_dclstack is not set, as a sanity measure. | |
testdclstack() | |
} | |
localpkg.Height = myheight | |
return lines | |
} | |
// makeSrcPosBase translates from a *syntax.PosBase to a *src.PosBase. | |
func (p *noder) makeSrcPosBase(b0 *syntax.PosBase) *src.PosBase { | |
// fast path: most likely PosBase hasn't changed | |
if p.basecache.last == b0 { | |
return p.basecache.base | |
} | |
b1, ok := p.basemap[b0] | |
if !ok { | |
fn := b0.Filename() | |
if b0.IsFileBase() { | |
b1 = src.NewFileBase(fn, absFilename(fn)) | |
} else { | |
// line directive base | |
p0 := b0.Pos() | |
p1 := src.MakePos(p.makeSrcPosBase(p0.Base()), p0.Line(), p0.Col()) | |
b1 = src.NewLinePragmaBase(p1, fn, fileh(fn), b0.Line(), b0.Col()) | |
} | |
p.basemap[b0] = b1 | |
} | |
// update cache | |
p.basecache.last = b0 | |
p.basecache.base = b1 | |
return b1 | |
} | |
func (p *noder) makeXPos(pos syntax.Pos) (_ src.XPos) { | |
return Ctxt.PosTable.XPos(src.MakePos(p.makeSrcPosBase(pos.Base()), pos.Line(), pos.Col())) | |
} | |
func (p *noder) yyerrorpos(pos syntax.Pos, format string, args ...interface{}) { | |
yyerrorl(p.makeXPos(pos), format, args...) | |
} | |
var pathPrefix string | |
// TODO(gri) Can we eliminate fileh in favor of absFilename? | |
func fileh(name string) string { | |
return objabi.AbsFile("", name, pathPrefix) | |
} | |
func absFilename(name string) string { | |
return objabi.AbsFile(Ctxt.Pathname, name, pathPrefix) | |
} | |
// noder transforms package syntax's AST into a Node tree. | |
type noder struct { | |
basemap map[*syntax.PosBase]*src.PosBase | |
basecache struct { | |
last *syntax.PosBase | |
base *src.PosBase | |
} | |
file *syntax.File | |
linknames []linkname | |
pragcgobuf [][]string | |
err chan syntax.Error | |
scope ScopeID | |
// scopeVars is a stack tracking the number of variables declared in the | |
// current function at the moment each open scope was opened. | |
scopeVars []int | |
lastCloseScopePos syntax.Pos | |
} | |
func (p *noder) funcBody(fn *Node, block *syntax.BlockStmt) { | |
oldScope := p.scope | |
p.scope = 0 | |
funchdr(fn) | |
if block != nil { | |
body := p.stmts(block.List) | |
if body == nil { | |
body = []*Node{nod(OEMPTY, nil, nil)} | |
} | |
fn.Nbody.Set(body) | |
lineno = p.makeXPos(block.Rbrace) | |
fn.Func.Endlineno = lineno | |
} | |
funcbody() | |
p.scope = oldScope | |
} | |
func (p *noder) openScope(pos syntax.Pos) { | |
types.Markdcl() | |
if trackScopes { | |
Curfn.Func.Parents = append(Curfn.Func.Parents, p.scope) | |
p.scopeVars = append(p.scopeVars, len(Curfn.Func.Dcl)) | |
p.scope = ScopeID(len(Curfn.Func.Parents)) | |
p.markScope(pos) | |
} | |
} | |
func (p *noder) closeScope(pos syntax.Pos) { | |
p.lastCloseScopePos = pos | |
types.Popdcl() | |
if trackScopes { | |
scopeVars := p.scopeVars[len(p.scopeVars)-1] | |
p.scopeVars = p.scopeVars[:len(p.scopeVars)-1] | |
if scopeVars == len(Curfn.Func.Dcl) { | |
// no variables were declared in this scope, so we can retract it. | |
if int(p.scope) != len(Curfn.Func.Parents) { | |
Fatalf("scope tracking inconsistency, no variables declared but scopes were not retracted") | |
} | |
p.scope = Curfn.Func.Parents[p.scope-1] | |
Curfn.Func.Parents = Curfn.Func.Parents[:len(Curfn.Func.Parents)-1] | |
nmarks := len(Curfn.Func.Marks) | |
Curfn.Func.Marks[nmarks-1].Scope = p.scope | |
prevScope := ScopeID(0) | |
if nmarks >= 2 { | |
prevScope = Curfn.Func.Marks[nmarks-2].Scope | |
} | |
if Curfn.Func.Marks[nmarks-1].Scope == prevScope { | |
Curfn.Func.Marks = Curfn.Func.Marks[:nmarks-1] | |
} | |
return | |
} | |
p.scope = Curfn.Func.Parents[p.scope-1] | |
p.markScope(pos) | |
} | |
} | |
func (p *noder) markScope(pos syntax.Pos) { | |
xpos := p.makeXPos(pos) | |
if i := len(Curfn.Func.Marks); i > 0 && Curfn.Func.Marks[i-1].Pos == xpos { | |
Curfn.Func.Marks[i-1].Scope = p.scope | |
} else { | |
Curfn.Func.Marks = append(Curfn.Func.Marks, Mark{xpos, p.scope}) | |
} | |
} | |
// closeAnotherScope is like closeScope, but it reuses the same mark | |
// position as the last closeScope call. This is useful for "for" and | |
// "if" statements, as their implicit blocks always end at the same | |
// position as an explicit block. | |
func (p *noder) closeAnotherScope() { | |
p.closeScope(p.lastCloseScopePos) | |
} | |
// linkname records a //go:linkname directive. | |
type linkname struct { | |
pos syntax.Pos | |
local string | |
remote string | |
} | |
func (p *noder) node() { | |
types.Block = 1 | |
imported_unsafe = false | |
p.setlineno(p.file.PkgName) | |
mkpackage(p.file.PkgName.Value) | |
if pragma, ok := p.file.Pragma.(*Pragma); ok { | |
p.checkUnused(pragma) | |
} | |
xtop = append(xtop, p.decls(p.file.DeclList)...) | |
for _, n := range p.linknames { | |
if !imported_unsafe { | |
p.yyerrorpos(n.pos, "//go:linkname only allowed in Go files that import \"unsafe\"") | |
continue | |
} | |
s := lookup(n.local) | |
if n.remote != "" { | |
s.Linkname = n.remote | |
} else { | |
// Use the default object symbol name if the | |
// user didn't provide one. | |
if myimportpath == "" { | |
p.yyerrorpos(n.pos, "//go:linkname requires linkname argument or -p compiler flag") | |
} else { | |
s.Linkname = objabi.PathToPrefix(myimportpath) + "." + n.local | |
} | |
} | |
} | |
// The linker expects an ABI0 wrapper for all cgo-exported | |
// functions. | |
for _, prag := range p.pragcgobuf { | |
switch prag[0] { | |
case "cgo_export_static", "cgo_export_dynamic": | |
if symabiRefs == nil { | |
symabiRefs = make(map[string]obj.ABI) | |
} | |
symabiRefs[prag[1]] = obj.ABI0 | |
} | |
} | |
pragcgobuf = append(pragcgobuf, p.pragcgobuf...) | |
lineno = src.NoXPos | |
clearImports() | |
} | |
func (p *noder) decls(decls []syntax.Decl) (l []*Node) { | |
var cs constState | |
for _, decl := range decls { | |
p.setlineno(decl) | |
switch decl := decl.(type) { | |
case *syntax.ImportDecl: | |
p.importDecl(decl) | |
case *syntax.VarDecl: | |
l = append(l, p.varDecl(decl)...) | |
case *syntax.ConstDecl: | |
l = append(l, p.constDecl(decl, &cs)...) | |
case *syntax.TypeDecl: | |
l = append(l, p.typeDecl(decl)) | |
case *syntax.FuncDecl: | |
l = append(l, p.funcDecl(decl)) | |
default: | |
panic("unhandled Decl") | |
} | |
} | |
return | |
} | |
func (p *noder) importDecl(imp *syntax.ImportDecl) { | |
if imp.Path.Bad { | |
return // avoid follow-on errors if there was a syntax error | |
} | |
if pragma, ok := imp.Pragma.(*Pragma); ok { | |
p.checkUnused(pragma) | |
} | |
val := p.basicLit(imp.Path) | |
ipkg := importfile(&val) | |
if ipkg == nil { | |
if nerrors == 0 { | |
Fatalf("phase error in import") | |
} | |
return | |
} | |
ipkg.Direct = true | |
var my *types.Sym | |
if imp.LocalPkgName != nil { | |
my = p.name(imp.LocalPkgName) | |
} else { | |
my = lookup(ipkg.Name) | |
} | |
pack := p.nod(imp, OPACK, nil, nil) | |
pack.Sym = my | |
pack.Name.Pkg = ipkg | |
switch my.Name { | |
case ".": | |
importdot(ipkg, pack) | |
return | |
case "init": | |
yyerrorl(pack.Pos, "cannot import package as init - init must be a func") | |
return | |
case "_": | |
return | |
} | |
if my.Def != nil { | |
redeclare(pack.Pos, my, "as imported package name") | |
} | |
my.Def = asTypesNode(pack) | |
my.Lastlineno = pack.Pos | |
my.Block = 1 // at top level | |
} | |
func (p *noder) varDecl(decl *syntax.VarDecl) []*Node { | |
names := p.declNames(decl.NameList) | |
typ := p.typeExprOrNil(decl.Type) | |
var exprs []*Node | |
if decl.Values != nil { | |
exprs = p.exprList(decl.Values) | |
} | |
if pragma, ok := decl.Pragma.(*Pragma); ok { | |
p.checkUnused(pragma) | |
} | |
p.setlineno(decl) | |
return variter(names, typ, exprs) | |
} | |
// constState tracks state between constant specifiers within a | |
// declaration group. This state is kept separate from noder so nested | |
// constant declarations are handled correctly (e.g., issue 15550). | |
type constState struct { | |
group *syntax.Group | |
typ *Node | |
values []*Node | |
iota int64 | |
} | |
func (p *noder) constDecl(decl *syntax.ConstDecl, cs *constState) []*Node { | |
if decl.Group == nil || decl.Group != cs.group { | |
*cs = constState{ | |
group: decl.Group, | |
} | |
} | |
if pragma, ok := decl.Pragma.(*Pragma); ok { | |
p.checkUnused(pragma) | |
} | |
names := p.declNames(decl.NameList) | |
typ := p.typeExprOrNil(decl.Type) | |
var values []*Node | |
if decl.Values != nil { | |
values = p.exprList(decl.Values) | |
cs.typ, cs.values = typ, values | |
} else { | |
if typ != nil { | |
yyerror("const declaration cannot have type without expression") | |
} | |
typ, values = cs.typ, cs.values | |
} | |
nn := make([]*Node, 0, len(names)) | |
for i, n := range names { | |
if i >= len(values) { | |
yyerror("missing value in const declaration") | |
break | |
} | |
v := values[i] | |
if decl.Values == nil { | |
v = treecopy(v, n.Pos) | |
} | |
n.Op = OLITERAL | |
declare(n, dclcontext) | |
n.Name.Param.Ntype = typ | |
n.Name.Defn = v | |
n.SetIota(cs.iota) | |
nn = append(nn, p.nod(decl, ODCLCONST, n, nil)) | |
} | |
if len(values) > len(names) { | |
yyerror("extra expression in const declaration") | |
} | |
cs.iota++ | |
return nn | |
} | |
func (p *noder) typeDecl(decl *syntax.TypeDecl) *Node { | |
n := p.declName(decl.Name) | |
n.Op = OTYPE | |
declare(n, dclcontext) | |
// decl.Type may be nil but in that case we got a syntax error during parsing | |
typ := p.typeExprOrNil(decl.Type) | |
param := n.Name.Param | |
param.Ntype = typ | |
param.Alias = decl.Alias | |
if pragma, ok := decl.Pragma.(*Pragma); ok { | |
if !decl.Alias { | |
param.Pragma = pragma.Flag & TypePragmas | |
pragma.Flag &^= TypePragmas | |
} | |
p.checkUnused(pragma) | |
} | |
nod := p.nod(decl, ODCLTYPE, n, nil) | |
if param.Alias && !langSupported(1, 9, localpkg) { | |
yyerrorl(nod.Pos, "type aliases only supported as of -lang=go1.9") | |
} | |
return nod | |
} | |
func (p *noder) declNames(names []*syntax.Name) []*Node { | |
nodes := make([]*Node, 0, len(names)) | |
for _, name := range names { | |
nodes = append(nodes, p.declName(name)) | |
} | |
return nodes | |
} | |
func (p *noder) declName(name *syntax.Name) *Node { | |
n := dclname(p.name(name)) | |
n.Pos = p.pos(name) | |
return n | |
} | |
func (p *noder) funcDecl(fun *syntax.FuncDecl) *Node { | |
name := p.name(fun.Name) | |
t := p.signature(fun.Recv, fun.Type) | |
f := p.nod(fun, ODCLFUNC, nil, nil) | |
if fun.Recv == nil { | |
if name.Name == "init" { | |
name = renameinit() | |
if t.List.Len() > 0 || t.Rlist.Len() > 0 { | |
yyerrorl(f.Pos, "func init must have no arguments and no return values") | |
} | |
} | |
if localpkg.Name == "main" && name.Name == "main" { | |
if t.List.Len() > 0 || t.Rlist.Len() > 0 { | |
yyerrorl(f.Pos, "func main must have no arguments and no return values") | |
} | |
} | |
} else { | |
f.Func.Shortname = name | |
name = nblank.Sym // filled in by typecheckfunc | |
} | |
f.Func.Nname = newfuncnamel(p.pos(fun.Name), name) | |
f.Func.Nname.Name.Defn = f | |
f.Func.Nname.Name.Param.Ntype = t | |
if pragma, ok := fun.Pragma.(*Pragma); ok { | |
f.Func.Pragma = pragma.Flag & FuncPragmas | |
if pragma.Flag&Systemstack != 0 && pragma.Flag&Nosplit != 0 { | |
yyerrorl(f.Pos, "go:nosplit and go:systemstack cannot be combined") | |
} | |
pragma.Flag &^= FuncPragmas | |
p.checkUnused(pragma) | |
} | |
if fun.Recv == nil { | |
declare(f.Func.Nname, PFUNC) | |
} | |
p.funcBody(f, fun.Body) | |
if fun.Body != nil { | |
if f.Func.Pragma&Noescape != 0 { | |
yyerrorl(f.Pos, "can only use //go:noescape with external func implementations") | |
} | |
} else { | |
if pure_go || strings.HasPrefix(f.funcname(), "init.") { | |
// Linknamed functions are allowed to have no body. Hopefully | |
// the linkname target has a body. See issue 23311. | |
isLinknamed := false | |
for _, n := range p.linknames { | |
if f.funcname() == n.local { | |
isLinknamed = true | |
break | |
} | |
} | |
if !isLinknamed { | |
yyerrorl(f.Pos, "missing function body") | |
} | |
} | |
} | |
return f | |
} | |
func (p *noder) signature(recv *syntax.Field, typ *syntax.FuncType) *Node { | |
n := p.nod(typ, OTFUNC, nil, nil) | |
if recv != nil { | |
n.Left = p.param(recv, false, false) | |
} | |
n.List.Set(p.params(typ.ParamList, true)) | |
n.Rlist.Set(p.params(typ.ResultList, false)) | |
return n | |
} | |
func (p *noder) params(params []*syntax.Field, dddOk bool) []*Node { | |
nodes := make([]*Node, 0, len(params)) | |
for i, param := range params { | |
p.setlineno(param) | |
nodes = append(nodes, p.param(param, dddOk, i+1 == len(params))) | |
} | |
return nodes | |
} | |
func (p *noder) param(param *syntax.Field, dddOk, final bool) *Node { | |
var name *types.Sym | |
if param.Name != nil { | |
name = p.name(param.Name) | |
} | |
typ := p.typeExpr(param.Type) | |
n := p.nodSym(param, ODCLFIELD, typ, name) | |
// rewrite ...T parameter | |
if typ.Op == ODDD { | |
if !dddOk { | |
// We mark these as syntax errors to get automatic elimination | |
// of multiple such errors per line (see yyerrorl in subr.go). | |
yyerror("syntax error: cannot use ... in receiver or result parameter list") | |
} else if !final { | |
if param.Name == nil { | |
yyerror("syntax error: cannot use ... with non-final parameter") | |
} else { | |
p.yyerrorpos(param.Name.Pos(), "syntax error: cannot use ... with non-final parameter %s", param.Name.Value) | |
} | |
} | |
typ.Op = OTARRAY | |
typ.Right = typ.Left | |
typ.Left = nil | |
n.SetIsDDD(true) | |
if n.Left != nil { | |
n.Left.SetIsDDD(true) | |
} | |
} | |
return n | |
} | |
func (p *noder) exprList(expr syntax.Expr) []*Node { | |
if list, ok := expr.(*syntax.ListExpr); ok { | |
return p.exprs(list.ElemList) | |
} | |
return []*Node{p.expr(expr)} | |
} | |
func (p *noder) exprs(exprs []syntax.Expr) []*Node { | |
nodes := make([]*Node, 0, len(exprs)) | |
for _, expr := range exprs { | |
nodes = append(nodes, p.expr(expr)) | |
} | |
return nodes | |
} | |
func (p *noder) expr(expr syntax.Expr) *Node { | |
p.setlineno(expr) | |
switch expr := expr.(type) { | |
case nil, *syntax.BadExpr: | |
return nil | |
case *syntax.Name: | |
return p.mkname(expr) | |
case *syntax.BasicLit: | |
n := nodlit(p.basicLit(expr)) | |
n.SetDiag(expr.Bad) // avoid follow-on errors if there was a syntax error | |
return n | |
case *syntax.CompositeLit: | |
n := p.nod(expr, OCOMPLIT, nil, nil) | |
if expr.Type != nil { | |
n.Right = p.expr(expr.Type) | |
} | |
l := p.exprs(expr.ElemList) | |
for i, e := range l { | |
l[i] = p.wrapname(expr.ElemList[i], e) | |
} | |
n.List.Set(l) | |
lineno = p.makeXPos(expr.Rbrace) | |
return n | |
case *syntax.KeyValueExpr: | |
// use position of expr.Key rather than of expr (which has position of ':') | |
return p.nod(expr.Key, OKEY, p.expr(expr.Key), p.wrapname(expr.Value, p.expr(expr.Value))) | |
case *syntax.FuncLit: | |
return p.funcLit(expr) | |
case *syntax.ParenExpr: | |
return p.nod(expr, OPAREN, p.expr(expr.X), nil) | |
case *syntax.SelectorExpr: | |
// parser.new_dotname | |
obj := p.expr(expr.X) | |
if obj.Op == OPACK { | |
obj.Name.SetUsed(true) | |
return oldname(restrictlookup(expr.Sel.Value, obj.Name.Pkg)) | |
} | |
n := nodSym(OXDOT, obj, p.name(expr.Sel)) | |
n.Pos = p.pos(expr) // lineno may have been changed by p.expr(expr.X) | |
return n | |
case *syntax.IndexExpr: | |
return p.nod(expr, OINDEX, p.expr(expr.X), p.expr(expr.Index)) | |
case *syntax.SliceExpr: | |
op := OSLICE | |
if expr.Full { | |
op = OSLICE3 | |
} | |
n := p.nod(expr, op, p.expr(expr.X), nil) | |
var index [3]*Node | |
for i, x := range &expr.Index { | |
if x != nil { | |
index[i] = p.expr(x) | |
} | |
} | |
n.SetSliceBounds(index[0], index[1], index[2]) | |
return n | |
case *syntax.AssertExpr: | |
return p.nod(expr, ODOTTYPE, p.expr(expr.X), p.typeExpr(expr.Type)) | |
case *syntax.Operation: | |
if expr.Op == syntax.Add && expr.Y != nil { | |
return p.sum(expr) | |
} | |
x := p.expr(expr.X) | |
if expr.Y == nil { | |
return p.nod(expr, p.unOp(expr.Op), x, nil) | |
} | |
return p.nod(expr, p.binOp(expr.Op), x, p.expr(expr.Y)) | |
case *syntax.CallExpr: | |
n := p.nod(expr, OCALL, p.expr(expr.Fun), nil) | |
n.List.Set(p.exprs(expr.ArgList)) | |
n.SetIsDDD(expr.HasDots) | |
return n | |
case *syntax.ArrayType: | |
var len *Node | |
if expr.Len != nil { | |
len = p.expr(expr.Len) | |
} else { | |
len = p.nod(expr, ODDD, nil, nil) | |
} | |
return p.nod(expr, OTARRAY, len, p.typeExpr(expr.Elem)) | |
case *syntax.SliceType: | |
return p.nod(expr, OTARRAY, nil, p.typeExpr(expr.Elem)) | |
case *syntax.DotsType: | |
return p.nod(expr, ODDD, p.typeExpr(expr.Elem), nil) | |
case *syntax.StructType: | |
return p.structType(expr) | |
case *syntax.InterfaceType: | |
return p.interfaceType(expr) | |
case *syntax.FuncType: | |
return p.signature(nil, expr) | |
case *syntax.MapType: | |
return p.nod(expr, OTMAP, p.typeExpr(expr.Key), p.typeExpr(expr.Value)) | |
case *syntax.ChanType: | |
n := p.nod(expr, OTCHAN, p.typeExpr(expr.Elem), nil) | |
n.SetTChanDir(p.chanDir(expr.Dir)) | |
return n | |
case *syntax.TypeSwitchGuard: | |
n := p.nod(expr, OTYPESW, nil, p.expr(expr.X)) | |
if expr.Lhs != nil { | |
n.Left = p.declName(expr.Lhs) | |
if n.Left.isBlank() { | |
yyerror("invalid variable name %v in type switch", n.Left) | |
} | |
} | |
return n | |
} | |
panic("unhandled Expr") | |
} | |
// sum efficiently handles very large summation expressions (such as | |
// in issue #16394). In particular, it avoids left recursion and | |
// collapses string literals. | |
func (p *noder) sum(x syntax.Expr) *Node { | |
// While we need to handle long sums with asymptotic | |
// efficiency, the vast majority of sums are very small: ~95% | |
// have only 2 or 3 operands, and ~99% of string literals are | |
// never concatenated. | |
adds := make([]*syntax.Operation, 0, 2) | |
for { | |
add, ok := x.(*syntax.Operation) | |
if !ok || add.Op != syntax.Add || add.Y == nil { | |
break | |
} | |
adds = append(adds, add) | |
x = add.X | |
} | |
// nstr is the current rightmost string literal in the | |
// summation (if any), and chunks holds its accumulated | |
// substrings. | |
// | |
// Consider the expression x + "a" + "b" + "c" + y. When we | |
// reach the string literal "a", we assign nstr to point to | |
// its corresponding Node and initialize chunks to {"a"}. | |
// Visiting the subsequent string literals "b" and "c", we | |
// simply append their values to chunks. Finally, when we | |
// reach the non-constant operand y, we'll join chunks to form | |
// "abc" and reassign the "a" string literal's value. | |
// | |
// N.B., we need to be careful about named string constants | |
// (indicated by Sym != nil) because 1) we can't modify their | |
// value, as doing so would affect other uses of the string | |
// constant, and 2) they may have types, which we need to | |
// handle correctly. For now, we avoid these problems by | |
// treating named string constants the same as non-constant | |
// operands. | |
var nstr *Node | |
chunks := make([]string, 0, 1) | |
n := p.expr(x) | |
if Isconst(n, CTSTR) && n.Sym == nil { | |
nstr = n | |
chunks = append(chunks, strlit(nstr)) | |
} | |
for i := len(adds) - 1; i >= 0; i-- { | |
add := adds[i] | |
r := p.expr(add.Y) | |
if Isconst(r, CTSTR) && r.Sym == nil { | |
if nstr != nil { | |
// Collapse r into nstr instead of adding to n. | |
chunks = append(chunks, strlit(r)) | |
continue | |
} | |
nstr = r | |
chunks = append(chunks, strlit(nstr)) | |
} else { | |
if len(chunks) > 1 { | |
nstr.SetVal(Val{U: strings.Join(chunks, "")}) | |
} | |
nstr = nil | |
chunks = chunks[:0] | |
} | |
n = p.nod(add, OADD, n, r) | |
} | |
if len(chunks) > 1 { | |
nstr.SetVal(Val{U: strings.Join(chunks, "")}) | |
} | |
return n | |
} | |
func (p *noder) typeExpr(typ syntax.Expr) *Node { | |
// TODO(mdempsky): Be stricter? typecheck should handle errors anyway. | |
return p.expr(typ) | |
} | |
func (p *noder) typeExprOrNil(typ syntax.Expr) *Node { | |
if typ != nil { | |
return p.expr(typ) | |
} | |
return nil | |
} | |
func (p *noder) chanDir(dir syntax.ChanDir) types.ChanDir { | |
switch dir { | |
case 0: | |
return types.Cboth | |
case syntax.SendOnly: | |
return types.Csend | |
case syntax.RecvOnly: | |
return types.Crecv | |
} | |
panic("unhandled ChanDir") | |
} | |
func (p *noder) structType(expr *syntax.StructType) *Node { | |
l := make([]*Node, 0, len(expr.FieldList)) | |
for i, field := range expr.FieldList { | |
p.setlineno(field) | |
var n *Node | |
if field.Name == nil { | |
n = p.embedded(field.Type) | |
} else { | |
n = p.nodSym(field, ODCLFIELD, p.typeExpr(field.Type), p.name(field.Name)) | |
} | |
if i < len(expr.TagList) && expr.TagList[i] != nil { | |
n.SetVal(p.basicLit(expr.TagList[i])) | |
} | |
l = append(l, n) | |
} | |
p.setlineno(expr) | |
n := p.nod(expr, OTSTRUCT, nil, nil) | |
n.List.Set(l) | |
return n | |
} | |
func (p *noder) interfaceType(expr *syntax.InterfaceType) *Node { | |
l := make([]*Node, 0, len(expr.MethodList)) | |
for _, method := range expr.MethodList { | |
p.setlineno(method) | |
var n *Node | |
if method.Name == nil { | |
n = p.nodSym(method, ODCLFIELD, oldname(p.packname(method.Type)), nil) | |
} else { | |
mname := p.name(method.Name) | |
sig := p.typeExpr(method.Type) | |
sig.Left = fakeRecv() | |
n = p.nodSym(method, ODCLFIELD, sig, mname) | |
ifacedcl(n) | |
} | |
l = append(l, n) | |
} | |
n := p.nod(expr, OTINTER, nil, nil) | |
n.List.Set(l) | |
return n | |
} | |
func (p *noder) packname(expr syntax.Expr) *types.Sym { | |
switch expr := expr.(type) { | |
case *syntax.Name: | |
name := p.name(expr) | |
if n := oldname(name); n.Name != nil && n.Name.Pack != nil { | |
n.Name.Pack.Name.SetUsed(true) | |
} | |
return name | |
case *syntax.SelectorExpr: | |
name := p.name(expr.X.(*syntax.Name)) | |
def := asNode(name.Def) | |
if def == nil { | |
yyerror("undefined: %v", name) | |
return name | |
} | |
var pkg *types.Pkg | |
if def.Op != OPACK { | |
yyerror("%v is not a package", name) | |
pkg = localpkg | |
} else { | |
def.Name.SetUsed(true) | |
pkg = def.Name.Pkg | |
} | |
return restrictlookup(expr.Sel.Value, pkg) | |
} | |
panic(fmt.Sprintf("unexpected packname: %#v", expr)) | |
} | |
func (p *noder) embedded(typ syntax.Expr) *Node { | |
op, isStar := typ.(*syntax.Operation) | |
if isStar { | |
if op.Op != syntax.Mul || op.Y != nil { | |
panic("unexpected Operation") | |
} | |
typ = op.X | |
} | |
sym := p.packname(typ) | |
n := p.nodSym(typ, ODCLFIELD, oldname(sym), lookup(sym.Name)) | |
n.SetEmbedded(true) | |
if isStar { | |
n.Left = p.nod(op, ODEREF, n.Left, nil) | |
} | |
return n | |
} | |
func (p *noder) stmts(stmts []syntax.Stmt) []*Node { | |
return p.stmtsFall(stmts, false) | |
} | |
func (p *noder) stmtsFall(stmts []syntax.Stmt, fallOK bool) []*Node { | |
var nodes []*Node | |
for i, stmt := range stmts { | |
s := p.stmtFall(stmt, fallOK && i+1 == len(stmts)) | |
if s == nil { | |
} else if s.Op == OBLOCK && s.Ninit.Len() == 0 { | |
nodes = append(nodes, s.List.Slice()...) | |
} else { | |
nodes = append(nodes, s) | |
} | |
} | |
return nodes | |
} | |
func (p *noder) stmt(stmt syntax.Stmt) *Node { | |
return p.stmtFall(stmt, false) | |
} | |
func (p *noder) stmtFall(stmt syntax.Stmt, fallOK bool) *Node { | |
p.setlineno(stmt) | |
switch stmt := stmt.(type) { | |
case *syntax.EmptyStmt: | |
return nil | |
case *syntax.LabeledStmt: | |
return p.labeledStmt(stmt, fallOK) | |
case *syntax.BlockStmt: | |
l := p.blockStmt(stmt) | |
if len(l) == 0 { | |
// TODO(mdempsky): Line number? | |
return nod(OEMPTY, nil, nil) | |
} | |
return liststmt(l) | |
case *syntax.ExprStmt: | |
return p.wrapname(stmt, p.expr(stmt.X)) | |
case *syntax.SendStmt: | |
return p.nod(stmt, OSEND, p.expr(stmt.Chan), p.expr(stmt.Value)) | |
case *syntax.DeclStmt: | |
return liststmt(p.decls(stmt.DeclList)) | |
case *syntax.AssignStmt: | |
if stmt.Op != 0 && stmt.Op != syntax.Def { | |
n := p.nod(stmt, OASOP, p.expr(stmt.Lhs), p.expr(stmt.Rhs)) | |
n.SetImplicit(stmt.Rhs == syntax.ImplicitOne) | |
n.SetSubOp(p.binOp(stmt.Op)) | |
return n | |
} | |
n := p.nod(stmt, OAS, nil, nil) // assume common case | |
rhs := p.exprList(stmt.Rhs) | |
lhs := p.assignList(stmt.Lhs, n, stmt.Op == syntax.Def) | |
if len(lhs) == 1 && len(rhs) == 1 { | |
// common case | |
n.Left = lhs[0] | |
n.Right = rhs[0] | |
} else { | |
n.Op = OAS2 | |
n.List.Set(lhs) | |
n.Rlist.Set(rhs) | |
} | |
return n | |
case *syntax.BranchStmt: | |
var op Op | |
switch stmt.Tok { | |
case syntax.Break: | |
op = OBREAK | |
case syntax.Continue: | |
op = OCONTINUE | |
case syntax.Fallthrough: | |
if !fallOK { | |
yyerror("fallthrough statement out of place") | |
} | |
op = OFALL | |
case syntax.Goto: | |
op = OGOTO | |
default: | |
panic("unhandled BranchStmt") | |
} | |
n := p.nod(stmt, op, nil, nil) | |
if stmt.Label != nil { | |
n.Sym = p.name(stmt.Label) | |
} | |
return n | |
case *syntax.CallStmt: | |
var op Op | |
switch stmt.Tok { | |
case syntax.Defer: | |
op = ODEFER | |
case syntax.Go: | |
op = OGO | |
default: | |
panic("unhandled CallStmt") | |
} | |
return p.nod(stmt, op, p.expr(stmt.Call), nil) | |
case *syntax.ReturnStmt: | |
var results []*Node | |
if stmt.Results != nil { | |
results = p.exprList(stmt.Results) | |
} | |
n := p.nod(stmt, ORETURN, nil, nil) | |
n.List.Set(results) | |
if n.List.Len() == 0 && Curfn != nil { | |
for _, ln := range Curfn.Func.Dcl { | |
if ln.Class() == PPARAM { | |
continue | |
} | |
if ln.Class() != PPARAMOUT { | |
break | |
} | |
if asNode(ln.Sym.Def) != ln { | |
yyerror("%s is shadowed during return", ln.Sym.Name) | |
} | |
} | |
} | |
return n | |
case *syntax.IfStmt: | |
return p.ifStmt(stmt) | |
case *syntax.ForStmt: | |
return p.forStmt(stmt) | |
case *syntax.SwitchStmt: | |
return p.switchStmt(stmt) | |
case *syntax.SelectStmt: | |
return p.selectStmt(stmt) | |
} | |
panic("unhandled Stmt") | |
} | |
func (p *noder) assignList(expr syntax.Expr, defn *Node, colas bool) []*Node { | |
if !colas { | |
return p.exprList(expr) | |
} | |
defn.SetColas(true) | |
var exprs []syntax.Expr | |
if list, ok := expr.(*syntax.ListExpr); ok { | |
exprs = list.ElemList | |
} else { | |
exprs = []syntax.Expr{expr} | |
} | |
res := make([]*Node, len(exprs)) | |
seen := make(map[*types.Sym]bool, len(exprs)) | |
newOrErr := false | |
for i, expr := range exprs { | |
p.setlineno(expr) | |
res[i] = nblank | |
name, ok := expr.(*syntax.Name) | |
if !ok { | |
p.yyerrorpos(expr.Pos(), "non-name %v on left side of :=", p.expr(expr)) | |
newOrErr = true | |
continue | |
} | |
sym := p.name(name) | |
if sym.IsBlank() { | |
continue | |
} | |
if seen[sym] { | |
p.yyerrorpos(expr.Pos(), "%v repeated on left side of :=", sym) | |
newOrErr = true | |
continue | |
} | |
seen[sym] = true | |
if sym.Block == types.Block { | |
res[i] = oldname(sym) | |
continue | |
} | |
newOrErr = true | |
n := newname(sym) | |
declare(n, dclcontext) | |
n.Name.Defn = defn | |
defn.Ninit.Append(nod(ODCL, n, nil)) | |
res[i] = n | |
} | |
if !newOrErr { | |
yyerrorl(defn.Pos, "no new variables on left side of :=") | |
} | |
return res | |
} | |
func (p *noder) blockStmt(stmt *syntax.BlockStmt) []*Node { | |
p.openScope(stmt.Pos()) | |
nodes := p.stmts(stmt.List) | |
p.closeScope(stmt.Rbrace) | |
return nodes | |
} | |
func (p *noder) ifStmt(stmt *syntax.IfStmt) *Node { | |
p.openScope(stmt.Pos()) | |
n := p.nod(stmt, OIF, nil, nil) | |
if stmt.Init != nil { | |
n.Ninit.Set1(p.stmt(stmt.Init)) | |
} | |
if stmt.Cond != nil { | |
n.Left = p.expr(stmt.Cond) | |
} | |
n.Nbody.Set(p.blockStmt(stmt.Then)) | |
if stmt.Else != nil { | |
e := p.stmt(stmt.Else) | |
if e.Op == OBLOCK && e.Ninit.Len() == 0 { | |
n.Rlist.Set(e.List.Slice()) | |
} else { | |
n.Rlist.Set1(e) | |
} | |
} | |
p.closeAnotherScope() | |
return n | |
} | |
func (p *noder) forStmt(stmt *syntax.ForStmt) *Node { | |
p.openScope(stmt.Pos()) | |
var n *Node | |
if r, ok := stmt.Init.(*syntax.RangeClause); ok { | |
if stmt.Cond != nil || stmt.Post != nil { | |
panic("unexpected RangeClause") | |
} | |
n = p.nod(r, ORANGE, nil, p.expr(r.X)) | |
if r.Lhs != nil { | |
n.List.Set(p.assignList(r.Lhs, n, r.Def)) | |
} | |
} else { | |
n = p.nod(stmt, OFOR, nil, nil) | |
if stmt.Init != nil { | |
n.Ninit.Set1(p.stmt(stmt.Init)) | |
} | |
if stmt.Cond != nil { | |
n.Left = p.expr(stmt.Cond) | |
} | |
if stmt.Post != nil { | |
n.Right = p.stmt(stmt.Post) | |
} | |
} | |
n.Nbody.Set(p.blockStmt(stmt.Body)) | |
p.closeAnotherScope() | |
return n | |
} | |
func (p *noder) switchStmt(stmt *syntax.SwitchStmt) *Node { | |
p.openScope(stmt.Pos()) | |
n := p.nod(stmt, OSWITCH, nil, nil) | |
if stmt.Init != nil { | |
n.Ninit.Set1(p.stmt(stmt.Init)) | |
} | |
if stmt.Tag != nil { | |
n.Left = p.expr(stmt.Tag) | |
} | |
tswitch := n.Left | |
if tswitch != nil && tswitch.Op != OTYPESW { | |
tswitch = nil | |
} | |
n.List.Set(p.caseClauses(stmt.Body, tswitch, stmt.Rbrace)) | |
p.closeScope(stmt.Rbrace) | |
return n | |
} | |
func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *Node, rbrace syntax.Pos) []*Node { | |
nodes := make([]*Node, 0, len(clauses)) | |
for i, clause := range clauses { | |
p.setlineno(clause) | |
if i > 0 { | |
p.closeScope(clause.Pos()) | |
} | |
p.openScope(clause.Pos()) | |
n := p.nod(clause, OCASE, nil, nil) | |
if clause.Cases != nil { | |
n.List.Set(p.exprList(clause.Cases)) | |
} | |
if tswitch != nil && tswitch.Left != nil { | |
nn := newname(tswitch.Left.Sym) | |
declare(nn, dclcontext) | |
n.Rlist.Set1(nn) | |
// keep track of the instances for reporting unused | |
nn.Name.Defn = tswitch | |
} | |
// Trim trailing empty statements. We omit them from | |
// the Node AST anyway, and it's easier to identify | |
// out-of-place fallthrough statements without them. | |
body := clause.Body | |
for len(body) > 0 { | |
if _, ok := body[len(body)-1].(*syntax.EmptyStmt); !ok { | |
break | |
} | |
body = body[:len(body)-1] | |
} | |
n.Nbody.Set(p.stmtsFall(body, true)) | |
if l := n.Nbody.Len(); l > 0 && n.Nbody.Index(l-1).Op == OFALL { | |
if tswitch != nil { | |
yyerror("cannot fallthrough in type switch") | |
} | |
if i+1 == len(clauses) { | |
yyerror("cannot fallthrough final case in switch") | |
} | |
} | |
nodes = append(nodes, n) | |
} | |
if len(clauses) > 0 { | |
p.closeScope(rbrace) | |
} | |
return nodes | |
} | |
func (p *noder) selectStmt(stmt *syntax.SelectStmt) *Node { | |
n := p.nod(stmt, OSELECT, nil, nil) | |
n.List.Set(p.commClauses(stmt.Body, stmt.Rbrace)) | |
return n | |
} | |
func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []*Node { | |
nodes := make([]*Node, 0, len(clauses)) | |
for i, clause := range clauses { | |
p.setlineno(clause) | |
if i > 0 { | |
p.closeScope(clause.Pos()) | |
} | |
p.openScope(clause.Pos()) | |
n := p.nod(clause, OCASE, nil, nil) | |
if clause.Comm != nil { | |
n.List.Set1(p.stmt(clause.Comm)) | |
} | |
n.Nbody.Set(p.stmts(clause.Body)) | |
nodes = append(nodes, n) | |
} | |
if len(clauses) > 0 { | |
p.closeScope(rbrace) | |
} | |
return nodes | |
} | |
func (p *noder) labeledStmt(label *syntax.LabeledStmt, fallOK bool) *Node { | |
lhs := p.nodSym(label, OLABEL, nil, p.name(label.Label)) | |
var ls *Node | |
if label.Stmt != nil { // TODO(mdempsky): Should always be present. | |
ls = p.stmtFall(label.Stmt, fallOK) | |
} | |
lhs.Name.Defn = ls | |
l := []*Node{lhs} | |
if ls != nil { | |
if ls.Op == OBLOCK && ls.Ninit.Len() == 0 { | |
l = append(l, ls.List.Slice()...) | |
} else { | |
l = append(l, ls) | |
} | |
} | |
return liststmt(l) | |
} | |
var unOps = [...]Op{ | |
syntax.Recv: ORECV, | |
syntax.Mul: ODEREF, | |
syntax.And: OADDR, | |
syntax.Not: ONOT, | |
syntax.Xor: OBITNOT, | |
syntax.Add: OPLUS, | |
syntax.Sub: ONEG, | |
} | |
func (p *noder) unOp(op syntax.Operator) Op { | |
if uint64(op) >= uint64(len(unOps)) || unOps[op] == 0 { | |
panic("invalid Operator") | |
} | |
return unOps[op] | |
} | |
var binOps = [...]Op{ | |
syntax.OrOr: OOROR, | |
syntax.AndAnd: OANDAND, | |
syntax.Eql: OEQ, | |
syntax.Neq: ONE, | |
syntax.Lss: OLT, | |
syntax.Leq: OLE, | |
syntax.Gtr: OGT, | |
syntax.Geq: OGE, | |
syntax.Add: OADD, | |
syntax.Sub: OSUB, | |
syntax.Or: OOR, | |
syntax.Xor: OXOR, | |
syntax.Mul: OMUL, | |
syntax.Div: ODIV, | |
syntax.Rem: OMOD, | |
syntax.And: OAND, | |
syntax.AndNot: OANDNOT, | |
syntax.Shl: OLSH, | |
syntax.Shr: ORSH, | |
} | |
func (p *noder) binOp(op syntax.Operator) Op { | |
if uint64(op) >= uint64(len(binOps)) || binOps[op] == 0 { | |
panic("invalid Operator") | |
} | |
return binOps[op] | |
} | |
// checkLangCompat reports an error if the representation of a numeric | |
// literal is not compatible with the current language version. | |
func checkLangCompat(lit *syntax.BasicLit) { | |
s := lit.Value | |
if len(s) <= 2 || langSupported(1, 13, localpkg) { | |
return | |
} | |
// len(s) > 2 | |
if strings.Contains(s, "_") { | |
yyerrorv("go1.13", "underscores in numeric literals") | |
return | |
} | |
if s[0] != '0' { | |
return | |
} | |
base := s[1] | |
if base == 'b' || base == 'B' { | |
yyerrorv("go1.13", "binary literals") | |
return | |
} | |
if base == 'o' || base == 'O' { | |
yyerrorv("go1.13", "0o/0O-style octal literals") | |
return | |
} | |
if lit.Kind != syntax.IntLit && (base == 'x' || base == 'X') { | |
yyerrorv("go1.13", "hexadecimal floating-point literals") | |
} | |
} | |
func (p *noder) basicLit(lit *syntax.BasicLit) Val { | |
// We don't use the errors of the conversion routines to determine | |
// if a literal string is valid because the conversion routines may | |
// accept a wider syntax than the language permits. Rely on lit.Bad | |
// instead. | |
switch s := lit.Value; lit.Kind { | |
case syntax.IntLit: | |
checkLangCompat(lit) | |
x := new(Mpint) | |
if !lit.Bad { | |
x.SetString(s) | |
} | |
return Val{U: x} | |
case syntax.FloatLit: | |
checkLangCompat(lit) | |
x := newMpflt() | |
if !lit.Bad { | |
x.SetString(s) | |
} | |
return Val{U: x} | |
case syntax.ImagLit: | |
checkLangCompat(lit) | |
x := newMpcmplx() | |
if !lit.Bad { | |
x.Imag.SetString(strings.TrimSuffix(s, "i")) | |
} | |
return Val{U: x} | |
case syntax.RuneLit: | |
x := new(Mpint) | |
x.Rune = true | |
if !lit.Bad { | |
u, _ := strconv.Unquote(s) | |
var r rune | |
if len(u) == 1 { | |
r = rune(u[0]) | |
} else { | |
r, _ = utf8.DecodeRuneInString(u) | |
} | |
x.SetInt64(int64(r)) | |
} | |
return Val{U: x} | |
case syntax.StringLit: | |
var x string | |
if !lit.Bad { | |
if len(s) > 0 && s[0] == '`' { | |
// strip carriage returns from raw string | |
s = strings.Replace(s, "\r", "", -1) | |
} | |
x, _ = strconv.Unquote(s) | |
} | |
return Val{U: x} | |
default: | |
panic("unhandled BasicLit kind") | |
} | |
} | |
func (p *noder) name(name *syntax.Name) *types.Sym { | |
return lookup(name.Value) | |
} | |
func (p *noder) mkname(name *syntax.Name) *Node { | |
// TODO(mdempsky): Set line number? | |
return mkname(p.name(name)) | |
} | |
func (p *noder) newname(name *syntax.Name) *Node { | |
// TODO(mdempsky): Set line number? | |
return newname(p.name(name)) | |
} | |
func (p *noder) wrapname(n syntax.Node, x *Node) *Node { | |
// These nodes do not carry line numbers. | |
// Introduce a wrapper node to give them the correct line. | |
switch x.Op { | |
case OTYPE, OLITERAL: | |
if x.Sym == nil { | |
break | |
} | |
fallthrough | |
case ONAME, ONONAME, OPACK: | |
x = p.nod(n, OPAREN, x, nil) | |
x.SetImplicit(true) | |
} | |
return x | |
} | |
func (p *noder) nod(orig syntax.Node, op Op, left, right *Node) *Node { | |
return nodl(p.pos(orig), op, left, right) | |
} | |
func (p *noder) nodSym(orig syntax.Node, op Op, left *Node, sym *types.Sym) *Node { | |
n := nodSym(op, left, sym) | |
n.Pos = p.pos(orig) | |
return n | |
} | |
func (p *noder) pos(n syntax.Node) src.XPos { | |
// TODO(gri): orig.Pos() should always be known - fix package syntax | |
xpos := lineno | |
if pos := n.Pos(); pos.IsKnown() { | |
xpos = p.makeXPos(pos) | |
} | |
return xpos | |
} | |
func (p *noder) setlineno(n syntax.Node) { | |
if n != nil { | |
lineno = p.pos(n) | |
} | |
} | |
// error is called concurrently if files are parsed concurrently. | |
func (p *noder) error(err error) { | |
p.err <- err.(syntax.Error) | |
} | |
// pragmas that are allowed in the std lib, but don't have | |
// a syntax.Pragma value (see lex.go) associated with them. | |
var allowedStdPragmas = map[string]bool{ | |
"go:cgo_export_static": true, | |
"go:cgo_export_dynamic": true, | |
"go:cgo_import_static": true, | |
"go:cgo_import_dynamic": true, | |
"go:cgo_ldflag": true, | |
"go:cgo_dynamic_linker": true, | |
"go:generate": true, | |
} | |
// *Pragma is the value stored in a syntax.Pragma during parsing. | |
type Pragma struct { | |
Flag PragmaFlag // collected bits | |
Pos []PragmaPos // position of each individual flag | |
} | |
type PragmaPos struct { | |
Flag PragmaFlag | |
Pos syntax.Pos | |
} | |
func (p *noder) checkUnused(pragma *Pragma) { | |
for _, pos := range pragma.Pos { | |
if pos.Flag&pragma.Flag != 0 { | |
p.yyerrorpos(pos.Pos, "misplaced compiler directive") | |
} | |
} | |
} | |
func (p *noder) checkUnusedDuringParse(pragma *Pragma) { | |
for _, pos := range pragma.Pos { | |
if pos.Flag&pragma.Flag != 0 { | |
p.error(syntax.Error{Pos: pos.Pos, Msg: "misplaced compiler directive"}) | |
} | |
} | |
} | |
// pragma is called concurrently if files are parsed concurrently. | |
func (p *noder) pragma(pos syntax.Pos, blankLine bool, text string, old syntax.Pragma) syntax.Pragma { | |
pragma, _ := old.(*Pragma) | |
if pragma == nil { | |
pragma = new(Pragma) | |
} | |
if text == "" { | |
// unused pragma; only called with old != nil. | |
p.checkUnusedDuringParse(pragma) | |
return nil | |
} | |
if strings.HasPrefix(text, "line ") { | |
// line directives are handled by syntax package | |
panic("unreachable") | |
} | |
if !blankLine { | |
// directive must be on line by itself | |
p.error(syntax.Error{Pos: pos, Msg: "misplaced compiler directive"}) | |
return pragma | |
} | |
switch { | |
case strings.HasPrefix(text, "go:linkname "): | |
f := strings.Fields(text) | |
if !(2 <= len(f) && len(f) <= 3) { | |
p.error(syntax.Error{Pos: pos, Msg: "usage: //go:linkname localname [linkname]"}) | |
break | |
} | |
// The second argument is optional. If omitted, we use | |
// the default object symbol name for this and | |
// linkname only serves to mark this symbol as | |
// something that may be referenced via the object | |
// symbol name from another package. | |
var target string | |
if len(f) == 3 { | |
target = f[2] | |
} | |
p.linknames = append(p.linknames, linkname{pos, f[1], target}) | |
case strings.HasPrefix(text, "go:cgo_import_dynamic "): | |
// This is permitted for general use because Solaris | |
// code relies on it in golang.org/x/sys/unix and others. | |
fields := pragmaFields(text) | |
if len(fields) >= 4 { | |
lib := strings.Trim(fields[3], `"`) | |
if lib != "" && !safeArg(lib) && !isCgoGeneratedFile(pos) { | |
p.error(syntax.Error{Pos: pos, Msg: fmt.Sprintf("invalid library name %q in cgo_import_dynamic directive", lib)}) | |
} | |
p.pragcgo(pos, text) | |
pragma.Flag |= pragmaFlag("go:cgo_import_dynamic") | |
break | |
} | |
fallthrough | |
case strings.HasPrefix(text, "go:cgo_"): | |
// For security, we disallow //go:cgo_* directives other | |
// than cgo_import_dynamic outside cgo-generated files. | |
// Exception: they are allowed in the standard library, for runtime and syscall. | |
if !isCgoGeneratedFile(pos) && !compiling_std { | |
p.error(syntax.Error{Pos: pos, Msg: fmt.Sprintf("//%s only allowed in cgo-generated code", text)}) | |
} | |
p.pragcgo(pos, text) | |
fallthrough // because of //go:cgo_unsafe_args | |
default: | |
verb := text | |
if i := strings.Index(text, " "); i >= 0 { | |
verb = verb[:i] | |
} | |
flag := pragmaFlag(verb) | |
const runtimePragmas = Systemstack | Nowritebarrier | Nowritebarrierrec | Yeswritebarrierrec | |
if !compiling_runtime && flag&runtimePragmas != 0 { | |
p.error(syntax.Error{Pos: pos, Msg: fmt.Sprintf("//%s only allowed in runtime", verb)}) | |
} | |
if flag == 0 && !allowedStdPragmas[verb] && compiling_std { | |
p.error(syntax.Error{Pos: pos, Msg: fmt.Sprintf("//%s is not allowed in the standard library", verb)}) | |
} | |
pragma.Flag |= flag | |
pragma.Pos = append(pragma.Pos, PragmaPos{flag, pos}) | |
} | |
return pragma | |
} | |
// isCgoGeneratedFile reports whether pos is in a file | |
// generated by cgo, which is to say a file with name | |
// beginning with "_cgo_". Such files are allowed to | |
// contain cgo directives, and for security reasons | |
// (primarily misuse of linker flags), other files are not. | |
// See golang.org/issue/23672. | |
func isCgoGeneratedFile(pos syntax.Pos) bool { | |
return strings.HasPrefix(filepath.Base(filepath.Clean(fileh(pos.Base().Filename()))), "_cgo_") | |
} | |
// safeArg reports whether arg is a "safe" command-line argument, | |
// meaning that when it appears in a command-line, it probably | |
// doesn't have some special meaning other than its own name. | |
// This is copied from SafeArg in cmd/go/internal/load/pkg.go. | |
func safeArg(name string) bool { | |
if name == "" { | |
return false | |
} | |
c := name[0] | |
return '0' <= c && c <= '9' || 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || c == '.' || c == '_' || c == '/' || c >= utf8.RuneSelf | |
} | |
func mkname(sym *types.Sym) *Node { | |
n := oldname(sym) | |
if n.Name != nil && n.Name.Pack != nil { | |
n.Name.Pack.Name.SetUsed(true) | |
} | |
return n | |
} | |
func unparen(x *Node) *Node { | |
for x.Op == OPAREN { | |
x = x.Left | |
} | |
return x | |
} |