go/scanner: report illegal escape sequences

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/1636043

diff --git a/src/cmd/gofmt/test.sh b/src/cmd/gofmt/test.sh
index f21f3609a9819f8654dbd5c8be31f4d42d9cd7d9..bed46532b87c39bc72ccc607b5adae704e37f394 100755 (executable)
--- a/src/cmd/gofmt/test.sh
+++ b/src/cmd/gofmt/test.sh
@@ -36,7 +36,7 @@ apply1() {
        # the following files are skipped because they are test cases
        # for syntax errors and thus won't parse in the first place:
        case `basename "$F"` in
-       func3.go | const2.go | \
+       func3.go | const2.go | char_lit1.go | \
        bug014.go | bug050.go |  bug068.go |  bug083.go | bug088.go | \
        bug106.go | bug121.go | bug125.go | bug133.go | bug160.go | \
        bug163.go | bug166.go | bug169.go | bug217.go | bug222.go | \

diff --git a/src/pkg/go/scanner/scanner.go b/src/pkg/go/scanner/scanner.go
index 576b95a2896f919b15094dcc8f86772df1cafd90..e5ac9d7729c15ffc4cd1cbce68c20ba6ba65fd99 100644 (file)
--- a/src/pkg/go/scanner/scanner.go
+++ b/src/pkg/go/scanner/scanner.go
@@ -345,34 +345,43 @@ exit:
 }
 
 
-func (S *Scanner) scanDigits(base, length int) {
-       for length > 0 && digitVal(S.ch) < base {
-               S.next()
-               length--
-       }
-       if length > 0 {
-               S.error(S.pos, "illegal char escape")
-       }
-}
-
-
 func (S *Scanner) scanEscape(quote int) {
        pos := S.pos
-       ch := S.ch
-       S.next()
-       switch ch {
+
+       var i, base, max uint32
+       switch S.ch {
        case 'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', quote:
-       // nothing to do
+               S.next()
+               return
        case '0', '1', '2', '3', '4', '5', '6', '7':
-               S.scanDigits(8, 3-1) // 1 char read already
+               i, base, max = 3, 8, 255
        case 'x':
-               S.scanDigits(16, 2)
+               S.next()
+               i, base, max = 2, 16, 255
        case 'u':
-               S.scanDigits(16, 4)
+               S.next()
+               i, base, max = 4, 16, unicode.MaxRune
        case 'U':
-               S.scanDigits(16, 8)
+               S.next()
+               i, base, max = 8, 16, unicode.MaxRune
        default:
-               S.error(pos, "illegal char escape")
+               S.next() // always make progress
+               S.error(pos, "unknown escape sequence")
+               return
+       }
+
+       var x uint32
+       for ; i > 0; i-- {
+               d := uint32(digitVal(S.ch))
+               if d > base {
+                       S.error(S.pos, "illegal character in escape sequence")
+                       return
+               }
+               x = x*base + d
+               S.next()
+       }
+       if x > max || 0xd800 <= x && x < 0xe000 {
+               S.error(pos, "escape sequence is invalid Unicode code point")
        }
 }