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[dev.inline] cmd/compile/internal/syntax: introduce general position info for nodes

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Reviewed in and cherry-picked from https://go-review.googlesource.com/#/c/33758/.
Minor adjustments in noder.go to fix merge.

Change-Id: Ibe429e327c7f8554f8ac205c61ce3738013aed98
Reviewed-on: https://go-review.googlesource.com/34231
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer 2016-11-29 16:13:09 -08:00
parent eaca0e0529
commit 8d20b25779
11 changed files with 380 additions and 111 deletions
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37
src/cmd/compile/internal/syntax/source.go
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@ -2,6 +2,12 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file implements source, a buffered rune reader
// which is specialized for the needs of the Go scanner:
// Contiguous sequences of runes (literals) are extracted
// directly as []byte without the need to re-encode the
// runes in UTF-8 (as would be necessary with bufio.Reader).
package syntax
import (
@ -23,7 +29,8 @@ type source struct {
buf [4 << 10]byte
offs int // source offset of buf
r0, r, w int // previous/current read and write buf positions, excluding sentinel
line0, line int // previous/current line
line0, line uint // previous/current line
col0, col uint // previous/current column
err error // pending io error
// literal buffer
@ -40,6 +47,7 @@ func (s *source) init(src io.Reader, errh ErrorHandler) {
s.offs = 0
s.r0, s.r, s.w = 0, 0, 0
s.line0, s.line = 1, 1
s.col0, s.col = 1, 1
s.err = nil
s.lit = s.lit[:0]
@ -47,11 +55,11 @@ func (s *source) init(src io.Reader, errh ErrorHandler) {
}
func (s *source) error(msg string) {
s.error_at(s.pos0(), s.line0, msg)
s.error_at(s.line0, s.col0, msg)
}
func (s *source) error_at(pos, line int, msg string) {
err := Error{pos, line, msg}
func (s *source) error_at(line, col uint, msg string) {
err := Error{line, col, msg}
if s.first == nil {
s.first = err
}
@ -61,18 +69,24 @@ func (s *source) error_at(pos, line int, msg string) {
s.errh(err)
}
// pos0 returns the byte position of the last character read.
func (s *source) pos0() int {
return s.offs + s.r0
// ungetr ungets the most recently read rune.
func (s *source) ungetr() {
s.r, s.line, s.col = s.r0, s.line0, s.col0
}
func (s *source) ungetr() {
s.r, s.line = s.r0, s.line0
// ungetr2 is like ungetr but enables a 2nd ungetr.
// It must not be called if one of the runes seen
// was a newline.
func (s *source) ungetr2() {
s.ungetr()
// line must not have changed
s.r0--
s.col0--
}
func (s *source) getr() rune {
redo:
s.r0, s.line0 = s.r, s.line
s.r0, s.line0, s.col0 = s.r, s.line, s.col
// We could avoid at least one test that is always taken in the
// for loop below by duplicating the common case code (ASCII)
@ -88,12 +102,14 @@ redo:
// (invariant: s.buf[s.w] == utf8.RuneSelf)
if b := s.buf[s.r]; b < utf8.RuneSelf {
s.r++
s.col++
if b == 0 {
s.error("invalid NUL character")
goto redo
}
if b == '\n' {
s.line++
s.col = 1
}
return rune(b)
}
@ -109,6 +125,7 @@ redo:
// uncommon case: not ASCII
r, w := utf8.DecodeRune(s.buf[s.r:s.w])
s.r += w
s.col++
if r == utf8.RuneError && w == 1 {
s.error("invalid UTF-8 encoding")