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[dev.inline] cmd/compile/internal/syntax: use syntax.Pos for all external positions

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- use syntax.Pos in syntax.Error (rather than line, col)
- use syntax.Pos in syntax.PragmaHandler (rather than just line)
- update uses
- better documentation in various places

Also:
- make Pos methods use Pos receiver (rather than *Pos)

Reviewed in and cherry-picked from https://go-review.googlesource.com/#/c/33891/.
With minor adjustments to noder.go to make merge compile.

Change-Id: I5507cea6c2be46a7677087c1aeb69382d31033eb
Reviewed-on: https://go-review.googlesource.com/34236
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer 2016-12-02 10:44:34 -08:00
parent 54ef0447fe
commit 3d5df64b3f
8 changed files with 93 additions and 64 deletions
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1
src/cmd/compile/fmt_test.go
View file

@ -650,6 +650,7 @@ var knownFormats = map[string]string{
"cmd/compile/internal/syntax.Node %T": "",
"cmd/compile/internal/syntax.Operator %d": "",
"cmd/compile/internal/syntax.Operator %s": "",
"cmd/compile/internal/syntax.Pos %s": "",
"cmd/compile/internal/syntax.token %d": "",
"cmd/compile/internal/syntax.token %q": "",
"cmd/compile/internal/syntax.token %s": "",

18
src/cmd/compile/internal/gc/noder.go
View file

@ -28,8 +28,8 @@ func parseFile(filename string) {
p.file(file)
if !imported_unsafe {
for _, x := range p.linknames {
p.error(syntax.Error{Line: x, Msg: "//go:linkname only allowed in Go files that import \"unsafe\""})
for _, pos := range p.linknames {
p.error(syntax.Error{Pos: pos, Msg: "//go:linkname only allowed in Go files that import \"unsafe\""})
}
}
@ -41,7 +41,7 @@ func parseFile(filename string) {
// noder transforms package syntax's AST into a Nod tree.
type noder struct {
baseline int32
linknames []uint // tracks //go:linkname lines
linknames []syntax.Pos // tracks //go:linkname positions
}
func (p *noder) file(file *syntax.File) {
@ -1011,7 +1011,7 @@ func (p *noder) error(err error) {
line := p.baseline
var msg string
if err, ok := err.(syntax.Error); ok {
line += int32(err.Line) - 1
line += int32(err.Pos.Line()) - 1
msg = err.Msg
} else {
msg = err.Error()
@ -1019,7 +1019,7 @@ func (p *noder) error(err error) {
yyerrorl(src.MakePos(line), "%s", msg)
}
func (p *noder) pragma(line uint, text string) syntax.Pragma {
func (p *noder) pragma(pos syntax.Pos, text string) syntax.Pragma {
switch {
case strings.HasPrefix(text, "line "):
// Want to use LastIndexByte below but it's not defined in Go1.4 and bootstrap fails.
@ -1033,23 +1033,23 @@ func (p *noder) pragma(line uint, text string) syntax.Pragma {
break
}
if n > 1e8 {
p.error(syntax.Error{Line: line, Msg: "line number out of range"})
p.error(syntax.Error{Pos: pos, Msg: "line number out of range"})
errorexit()
}
if n <= 0 {
break
}
lexlineno = src.MakePos(p.baseline + int32(line))
lexlineno = src.MakePos(p.baseline + int32(pos.Line()))
linehistupdate(text[5:i], n)
case strings.HasPrefix(text, "go:linkname "):
// Record line number so we can emit an error later if
// the file doesn't import package unsafe.
p.linknames = append(p.linknames, line)
p.linknames = append(p.linknames, pos)
f := strings.Fields(text)
if len(f) != 3 {
p.error(syntax.Error{Line: line, Msg: "usage: //go:linkname localname linkname"})
p.error(syntax.Error{Pos: pos, Msg: "usage: //go:linkname localname linkname"})
break
}
lookup(f[1]).Linkname = f[2]

9
src/cmd/compile/internal/syntax/nodes.go
View file

@ -8,7 +8,7 @@ package syntax
// Nodes
type Node interface {
Pos() *Pos
Pos() Pos
aNode()
init(p *parser)
}
@ -19,14 +19,15 @@ type node struct {
pos Pos
}
func (n *node) Pos() *Pos {
return &n.pos
func (n *node) Pos() Pos {
return n.pos
}
func (*node) aNode() {}
// TODO(gri) we may be able to get rid of init here and in Node
func (n *node) init(p *parser) {
n.pos = MakePos(p.base, p.line, p.col)
n.pos = p.pos()
}
// ----------------------------------------------------------------------------

78
src/cmd/compile/internal/syntax/parser.go
View file

@ -35,14 +35,26 @@ type parser struct {
func (p *parser) init(filename string, src io.Reader, errh ErrorHandler, pragh PragmaHandler) {
p.base = NewFileBase(filename)
p.errh = errh
p.scanner.init(src, p.error_at, func(line, col uint, text string) {
if strings.HasPrefix(text, "line ") {
p.updateBase(line, col, text[5:])
}
if pragh != nil {
p.pragma |= pragh(line, text)
}
}, gcCompat)
p.scanner.init(
src,
// Error and pragma handlers for scanner.
// Because the (line, col) positions passed to these
// handlers are always at or after the current reading
// position, it is save to use the most recent position
// base to compute the corresponding Pos value.
func(line, col uint, msg string) {
p.error_at(p.pos_at(line, col), msg)
},
func(line, col uint, text string) {
if strings.HasPrefix(text, "line ") {
p.updateBase(line, col, text[5:])
}
if pragh != nil {
p.pragma |= pragh(p.pos_at(line, col), text)
}
},
gcCompat,
)
p.first = nil
p.pragma = 0
@ -61,7 +73,7 @@ func (p *parser) updateBase(line, col uint, text string) {
nstr := text[i+1:]
n, err := strconv.Atoi(nstr)
if err != nil || n <= 0 || n > lineMax {
p.error_at(line, col+uint(i+1), "invalid line number: "+nstr)
p.error_at(p.pos_at(line, col+uint(i+1)), "invalid line number: "+nstr)
return
}
p.base = NewLinePragmaBase(MakePos(p.base.Pos().Base(), line, col), text[:i], uint(n))
@ -85,9 +97,14 @@ func (p *parser) want(tok token) {
// ----------------------------------------------------------------------------
// Error handling
// pos_at returns the Pos value for (line, col) and the current position base.
func (p *parser) pos_at(line, col uint) Pos {
return MakePos(p.base, line, col)
}
// error reports an error at the given position.
func (p *parser) error_at(line, col uint, msg string) {
err := Error{line, col, msg}
func (p *parser) error_at(pos Pos, msg string) {
err := Error{pos, msg}
if p.first == nil {
p.first = err
}
@ -97,13 +114,8 @@ func (p *parser) error_at(line, col uint, msg string) {
p.errh(err)
}
// error reports a (non-syntax) error at the current token position.
func (p *parser) error(msg string) {
p.error_at(p.line, p.col, msg)
}
// syntax_error_at reports a syntax error at the given position.
func (p *parser) syntax_error_at(line, col uint, msg string) {
func (p *parser) syntax_error_at(pos Pos, msg string) {
if trace {
defer p.trace("syntax_error (" + msg + ")")()
}
@ -122,7 +134,7 @@ func (p *parser) syntax_error_at(line, col uint, msg string) {
msg = ", " + msg
default:
// plain error - we don't care about current token
p.error_at(line, col, "syntax error: "+msg)
p.error_at(pos, "syntax error: "+msg)
return
}
@ -144,13 +156,13 @@ func (p *parser) syntax_error_at(line, col uint, msg string) {
tok = tokstring(p.tok)
}
p.error_at(line, col, "syntax error: unexpected "+tok+msg)
p.error_at(pos, "syntax error: unexpected "+tok+msg)
}
// syntax_error reports a syntax error at the current token position.
func (p *parser) syntax_error(msg string) {
p.syntax_error_at(p.line, p.col, msg)
}
// Convenience methods using the current token position.
func (p *parser) pos() Pos { return p.pos_at(p.line, p.col) }
func (p *parser) error(msg string) { p.error_at(p.pos(), msg) }
func (p *parser) syntax_error(msg string) { p.syntax_error_at(p.pos(), msg) }
// The stopset contains keywords that start a statement.
// They are good synchronization points in case of syntax
@ -1247,7 +1259,7 @@ func (p *parser) fieldDecl(styp *StructType) {
p.want(_Rparen)
tag := p.oliteral()
p.addField(styp, nil, typ, tag)
p.error("cannot parenthesize embedded type")
p.syntax_error("cannot parenthesize embedded type")
} else {
// '(' embed ')' oliteral
@ -1255,7 +1267,7 @@ func (p *parser) fieldDecl(styp *StructType) {
p.want(_Rparen)
tag := p.oliteral()
p.addField(styp, nil, typ, tag)
p.error("cannot parenthesize embedded type")
p.syntax_error("cannot parenthesize embedded type")
}
case _Star:
@ -1266,7 +1278,7 @@ func (p *parser) fieldDecl(styp *StructType) {
p.want(_Rparen)
tag := p.oliteral()
p.addField(styp, nil, typ, tag)
p.error("cannot parenthesize embedded type")
p.syntax_error("cannot parenthesize embedded type")
} else {
// '*' embed oliteral
@ -1334,7 +1346,7 @@ func (p *parser) methodDecl() *Field {
f.init(p)
f.Type = p.qualifiedName(nil)
p.want(_Rparen)
p.error("cannot parenthesize embedded type")
p.syntax_error("cannot parenthesize embedded type")
return f
default:
@ -1401,7 +1413,7 @@ func (p *parser) dotsType() *DotsType {
p.want(_DotDotDot)
t.Elem = p.tryType()
if t.Elem == nil {
p.error("final argument in variadic function missing type")
p.syntax_error("final argument in variadic function missing type")
}
return t
@ -1612,7 +1624,7 @@ func (p *parser) labeledStmt(label *Name) Stmt {
s.Stmt = p.stmt()
if s.Stmt == missing_stmt {
// report error at line of ':' token
p.syntax_error_at(label.Pos().Line(), label.Pos().Col(), "missing statement after label")
p.syntax_error_at(label.Pos(), "missing statement after label")
// we are already at the end of the labeled statement - no need to advance
return missing_stmt
}
@ -1695,7 +1707,7 @@ func (p *parser) header(forStmt bool) (init SimpleStmt, cond Expr, post SimpleSt
if p.tok != _Semi {
// accept potential varDecl but complain
if forStmt && p.got(_Var) {
p.error("var declaration not allowed in for initializer")
p.syntax_error("var declaration not allowed in for initializer")
}
init = p.simpleStmt(nil, forStmt)
// If we have a range clause, we are done.
@ -1748,7 +1760,7 @@ func (p *parser) ifStmt() *IfStmt {
p.want(_If)
s.Init, s.Cond, _ = p.header(false)
if s.Cond == nil {
p.error("missing condition in if statement")
p.syntax_error("missing condition in if statement")
}
if gcCompat {
@ -1764,7 +1776,7 @@ func (p *parser) ifStmt() *IfStmt {
case _Lbrace:
s.Else = p.blockStmt()
default:
p.error("else must be followed by if or statement block")
p.syntax_error("else must be followed by if or statement block")
p.advance(_Name, _Rbrace)
}
}
@ -2137,7 +2149,7 @@ func (p *parser) exprList() Expr {
list = append(list, p.expr())
}
t := new(ListExpr)
t.init(p) // TODO(gri) what is the correct thing here?
t.pos = x.Pos()
t.ElemList = list
x = t
}

10
src/cmd/compile/internal/syntax/pos.go
View file

@ -34,18 +34,18 @@ func MakePos(base *PosBase, line, col uint) Pos {
}
// Filename returns the name of the actual file containing this position.
func (p *Pos) Filename() string { return p.base.Pos().RelFilename() }
func (p Pos) Filename() string { return p.base.Pos().RelFilename() }
// Base returns the position base.
func (p *Pos) Base() *PosBase { return p.base }
func (p Pos) Base() *PosBase { return p.base }
// RelFilename returns the filename recorded with the position's base.
func (p *Pos) RelFilename() string { return p.base.Filename() }
func (p Pos) RelFilename() string { return p.base.Filename() }
// RelLine returns the line number relative to the positions's base.
func (p *Pos) RelLine() uint { b := p.base; return b.Line() + p.Line() - b.Pos().Line() }
func (p Pos) RelLine() uint { b := p.base; return b.Line() + p.Line() - b.Pos().Line() }
func (p *Pos) String() string {
func (p Pos) String() string {
b := p.base
if b == b.Pos().base {

12
src/cmd/compile/internal/syntax/scanner.go
View file

@ -41,6 +41,18 @@ func (s *scanner) init(src io.Reader, errh, pragh func(line, col uint, msg strin
s.nlsemi = false
}
// next advances the scanner by reading the next token.
//
// If a read, source encoding, or lexical error occurs, next
// calls the error handler installed with init. The handler
// must exist.
//
// If a //line or //go: directive is encountered, next
// calls the pragma handler installed with init, if not nil.
//
// The (line, col) position passed to the error and pragma
// handler is always at or after the current source reading
// position.
func (s *scanner) next() {
nlsemi := s.nlsemi
s.nlsemi = false

10
src/cmd/compile/internal/syntax/source.go
View file

@ -77,9 +77,13 @@ func (s *source) error(msg string) {
}
// getr reads and returns the next rune.
// If an error occurs, the error handler provided to init
// is called with position (line and column) information
// and error message before getr returns.
//
// If a read or source encoding error occurs, getr
// calls the error handler installed with init.
// The handler must exist.
//
// The (line, col) position passed to the error handler
// is always at the current source reading position.
func (s *source) getr() rune {
redo:
s.r0, s.line0, s.col0 = s.r, s.line, s.col

19
src/cmd/compile/internal/syntax/syntax.go
View file

@ -15,13 +15,12 @@ type Mode uint
// Error describes a syntax error. Error implements the error interface.
type Error struct {
// TODO(gri) Line, Col should be replaced with Pos, eventually.
Line, Col uint
Msg string
Pos Pos
Msg string
}
func (err Error) Error() string {
return fmt.Sprintf("%d: %s", err.Line, err.Msg)
return fmt.Sprintf("%s: %s", err.Pos, err.Msg)
}
var _ error = Error{} // verify that Error implements error
@ -37,11 +36,11 @@ type Pragma uint16
// A PragmaHandler is used to process //line and //go: directives as
// they're scanned. The returned Pragma value will be unioned into the
// next FuncDecl node.
type PragmaHandler func(line uint, text string) Pragma
type PragmaHandler func(pos Pos, text string) Pragma
// Parse parses a single Go source file from src and returns the corresponding
// syntax tree. If there are syntax errors, Parse will return the first error
// encountered. The filename is only used for position information.
// syntax tree. If there are errors, Parse will return the first error found.
// The filename is only used for position information.
//
// If errh != nil, it is called with each error encountered, and Parse will
// process as much source as possible. If errh is nil, Parse will terminate
@ -50,11 +49,11 @@ type PragmaHandler func(line uint, text string) Pragma
// If a PragmaHandler is provided, it is called with each pragma encountered.
//
// The Mode argument is currently ignored.
func Parse(filename string, src io.Reader, errh ErrorHandler, pragh PragmaHandler, mode Mode) (_ *File, err error) {
func Parse(filename string, src io.Reader, errh ErrorHandler, pragh PragmaHandler, mode Mode) (_ *File, first error) {
defer func() {
if p := recover(); p != nil {
var ok bool
if err, ok = p.(Error); ok {
if err, ok := p.(Error); ok {
first = err
return
}
panic(p)