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cmd/compile/internal/syntax: permit /*line file:line:col*/ directives

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R=go1.11

This implements parsing of /*line file:line*/ and /*line file:line:col*/
directives and also extends the optional column format to regular //line
directives, per #22662.

For a line directive to be recognized, its comment text must start with
the prefix "line " which is followed by one of the following:

:line
:line:col
filename:line
filename:line:col

with at least one : present. The line and col values must be unsigned
decimal integers; everything before is considered part of the filename.

Valid line directives are:

//line :123
//line :123:8
//line foo.go:123
//line C:foo.go:123	(filename is "C:foo.go")
//line C:foo.go:123:8	(filename is "C:foo.go")
/*line ::123*/		(filename is ":")

No matter the comment format, at the moment all directives act as if
they were in //line comments, and column information is ignored.
To be addressed in subsequent CLs.

For #22662.

Change-Id: I1a2dc54bacc94bc6cdedc5229ee13278971f314e
Reviewed-on: https://go-review.googlesource.com/86037
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer 2018-01-03 15:52:22 -08:00
parent e87f2a1b70
commit ac45cb9aa0
4 changed files with 170 additions and 37 deletions
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54
src/cmd/compile/internal/syntax/parser.go
View File

@ -47,8 +47,9 @@ func (p *parser) init(base *src.PosBase, r io.Reader, errh ErrorHandler, pragh P
p.error_at(p.pos_at(line, col), msg)
},
func(line, col uint, text string) {
if strings.HasPrefix(text, "line ") {
p.updateBase(line, col+5, text[5:])
const prefix = "line "
if strings.HasPrefix(text, prefix) {
p.updateBase(line, col+uint(len(prefix)), text[len(prefix):])
return
}
if pragh != nil {
@ -69,23 +70,54 @@ func (p *parser) init(base *src.PosBase, r io.Reader, errh ErrorHandler, pragh P
const lineMax = 1<<24 - 1 // TODO(gri) this limit is defined for src.Pos - fix
func (p *parser) updateBase(line, col uint, text string) {
// Want to use LastIndexByte below but it's not defined in Go1.4 and bootstrap fails.
i := strings.LastIndex(text, ":") // look from right (Windows filenames may contain ':')
if i < 0 {
i, n, ok := trailingDigits(text)
if i == 0 {
return // ignore (not a line directive)
}
nstr := text[i+1:]
n, err := strconv.Atoi(nstr)
if err != nil || n <= 0 || n > lineMax {
p.error_at(p.pos_at(line, col+uint(i+1)), "invalid line number: "+nstr)
// i > 0
if !ok {
// text has a suffix :xxx but xxx is not a number
p.error_at(p.pos_at(line, col+i), "invalid line number: "+text[i:])
return
}
filename := text[:i]
i2, n2, ok2 := trailingDigits(text[:i-1])
if ok2 {
//line filename:line:col
i, i2 = i2, i
n, n2 = n2, n
if n2 == 0 {
p.error_at(p.pos_at(line, col+i2), "invalid column number: "+text[i2:])
return
}
text = text[:i2-1] // lop off :col
}
if n == 0 || n > lineMax {
p.error_at(p.pos_at(line, col+i), "invalid line number: "+text[i:])
return
}
filename := text[:i-1] // lop off :line
absFilename := filename
if p.fileh != nil {
absFilename = p.fileh(filename)
}
p.base = src.NewLinePragmaBase(src.MakePos(p.base.Pos().Base(), line, col), filename, absFilename, uint(n))
// TODO(gri) pass column n2 to NewLinePragmaBase
p.base = src.NewLinePragmaBase(src.MakePos(p.base.Pos().Base(), line, col), filename, absFilename, uint(n) /*uint(n2)*/)
}
func trailingDigits(text string) (uint, uint, bool) {
// Want to use LastIndexByte below but it's not defined in Go1.4 and bootstrap fails.
i := strings.LastIndex(text, ":") // look from right (Windows filenames may contain ':')
if i < 0 {
return 0, 0, false // no ":"
}
// i >= 0
n, err := strconv.ParseUint(text[i+1:], 10, 0)
return uint(i + 1), uint(n), err == nil
}
func (p *parser) got(tok token) bool {

106
src/cmd/compile/internal/syntax/parser_test.go
View File

@ -182,25 +182,99 @@ func TestParseFile(t *testing.T) {
}
func TestLineDirectives(t *testing.T) {
// valid line directives lead to a syntax error after them
const valid = "syntax error: package statement must be first"
for _, test := range []struct {
src, msg string
filename string
line, col uint // 0-based
}{
// test validity of //line directive
{`//line :`, "invalid line number: ", "", 0, 8},
{`//line :x`, "invalid line number: x", "", 0, 8},
{`//line foo :`, "invalid line number: ", "", 0, 12},
{`//line foo:123abc`, "invalid line number: 123abc", "", 0, 11},
{`/**///line foo:x`, "syntax error: package statement must be first", "", 0, 16}, //line directive not at start of line - ignored
{`//line foo:0`, "invalid line number: 0", "", 0, 11},
{fmt.Sprintf(`//line foo:%d`, lineMax+1), fmt.Sprintf("invalid line number: %d", lineMax+1), "", 0, 11},
// ignored //line directives
{"//\n", valid, "", 2 - linebase, 0}, // no directive
{"//line\n", valid, "", 2 - linebase, 0}, // missing colon
{"//line foo\n", valid, "", 2 - linebase, 0}, // missing colon
{" //line foo:\n", valid, "", 2 - linebase, 0}, // not a line start
{"// line foo:\n", valid, "", 2 - linebase, 0}, // space between // and line
// test effect of //line directive on (relative) position information
{"//line foo:123\n foo", "syntax error: package statement must be first", "foo", 123 - linebase, 3},
{"//line foo:123\n//line bar:345\nfoo", "syntax error: package statement must be first", "bar", 345 - linebase, 0},
// invalid //line directives with one colon
{"//line :\n", "invalid line number: ", "", 0, 8},
{"//line :x\n", "invalid line number: x", "", 0, 8},
{"//line foo :\n", "invalid line number: ", "", 0, 12},
{"//line foo:x\n", "invalid line number: x", "", 0, 11},
{"//line foo:0\n", "invalid line number: 0", "", 0, 11},
{"//line foo:1 \n", "invalid line number: 1 ", "", 0, 11},
{"//line foo:-12\n", "invalid line number: -12", "", 0, 11},
{"//line C:foo:0\n", "invalid line number: 0", "", 0, 13},
{fmt.Sprintf("//line foo:%d\n", lineMax+1), fmt.Sprintf("invalid line number: %d", lineMax+1), "", 0, 11},
{"//line " + runtime.GOROOT() + "/src/a/a.go:123\n foo", "syntax error: package statement must be first", "$GOROOT/src/a/a.go", 123 - linebase, 3},
// invalid //line directives with two colons
{"//line ::\n", "invalid line number: ", "", 0, 9},
{"//line ::x\n", "invalid line number: x", "", 0, 9},
{"//line foo::123abc\n", "invalid line number: 123abc", "", 0, 12},
{"//line foo::0\n", "invalid line number: 0", "", 0, 12},
{"//line foo:0:1\n", "invalid line number: 0", "", 0, 11},
{"//line :123:0\n", "invalid column number: 0", "", 0, 12},
{"//line foo:123:0\n", "invalid column number: 0", "", 0, 15},
// effect of valid //line directives on positions
{"//line foo:123\n foo", valid, "foo", 123 - linebase, 3},
{"//line foo:123\n foo", valid, " foo", 123 - linebase, 3},
{"//line foo:123\n//line bar:345\nfoo", valid, "bar", 345 - linebase, 0},
{"//line C:foo:123\n", valid, "C:foo", 123 - linebase, 0},
{"//line " + runtime.GOROOT() + "/src/a/a.go:123\n foo", valid, "$GOROOT/src/a/a.go", 123 - linebase, 3},
{"//line :x:1\n", valid, ":x", 0, 0},
{"//line foo ::1\n", valid, "foo :", 0, 0},
{"//line foo:123abc:1\n", valid, "foo:123abc", 0, 0},
{"//line foo :123:1\n", valid, "foo ", 123 - linebase, 0},
{"//line ::123\n", valid, ":", 123 - linebase, 0},
// TODO(gri) add tests to verify correct column changes, once implemented
// ignored /*line directives
{"/**/", valid, "", 1 - linebase, 4}, // no directive
{"/*line*/", valid, "", 1 - linebase, 8}, // missing colon
{"/*line foo*/", valid, "", 1 - linebase, 12}, // missing colon
{" //line foo:*/", valid, "", 1 - linebase, 15}, // not a line start
{"/* line foo:*/", valid, "", 1 - linebase, 15}, // space between // and line
// invalid /*line directives with one colon
{"/*line :*/", "invalid line number: ", "", 0, 8},
{"/*line :x*/", "invalid line number: x", "", 0, 8},
{"/*line foo :*/", "invalid line number: ", "", 0, 12},
{"/*line foo:x*/", "invalid line number: x", "", 0, 11},
{"/*line foo:0*/", "invalid line number: 0", "", 0, 11},
{"/*line foo:1 */", "invalid line number: 1 ", "", 0, 11},
{"/*line C:foo:0*/", "invalid line number: 0", "", 0, 13},
{fmt.Sprintf("/*line foo:%d*/", lineMax+1), fmt.Sprintf("invalid line number: %d", lineMax+1), "", 0, 11},
// invalid /*line directives with two colons
{"/*line ::*/", "invalid line number: ", "", 0, 9},
{"/*line ::x*/", "invalid line number: x", "", 0, 9},
{"/*line foo::123abc*/", "invalid line number: 123abc", "", 0, 12},
{"/*line foo::0*/", "invalid line number: 0", "", 0, 12},
{"/*line foo:0:1*/", "invalid line number: 0", "", 0, 11},
{"/*line :123:0*/", "invalid column number: 0", "", 0, 12},
{"/*line foo:123:0*/", "invalid column number: 0", "", 0, 15},
// effect of valid /*line directives on positions
// TODO(gri) remove \n after directives once line number is computed correctly
{"/*line foo:123*/\n foo", valid, "foo", 123 - linebase, 3},
{"/*line foo:123*/\n//line bar:345\nfoo", valid, "bar", 345 - linebase, 0},
{"/*line C:foo:123*/\n", valid, "C:foo", 123 - linebase, 0},
{"/*line " + runtime.GOROOT() + "/src/a/a.go:123*/\n foo", valid, "$GOROOT/src/a/a.go", 123 - linebase, 3},
{"/*line :x:1*/\n", valid, ":x", 1 - linebase, 0},
{"/*line foo ::1*/\n", valid, "foo :", 1 - linebase, 0},
{"/*line foo:123abc:1*/\n", valid, "foo:123abc", 1 - linebase, 0},
{"/*line foo :123:1*/\n", valid, "foo ", 123 - linebase, 0},
{"/*line ::123*/\n", valid, ":", 123 - linebase, 0},
// test effect of /*line directive on (relative) position information for this line
// TODO(gri) add these tests
// TODO(gri) add tests to verify correct column changes, once implemented
} {
fileh := func(name string) string {
if strings.HasPrefix(name, runtime.GOROOT()) {
@ -224,11 +298,11 @@ func TestLineDirectives(t *testing.T) {
if filename := perr.Pos.AbsFilename(); filename != test.filename {
t.Errorf("%s: got filename = %q; want %q", test.src, filename, test.filename)
}
if line := perr.Pos.RelLine(); line != test.line+linebase {
t.Errorf("%s: got line = %d; want %d", test.src, line, test.line+linebase)
if line := perr.Pos.RelLine(); line-linebase != test.line {
t.Errorf("%s: got line = %d; want %d", test.src, line-linebase, test.line)
}
if col := perr.Pos.Col(); col != test.col+colbase {
t.Errorf("%s: got col = %d; want %d", test.src, col, test.col+colbase)
if col := perr.Pos.Col(); col-colbase != test.col {
t.Errorf("%s: got col = %d; want %d", test.src, col-colbase, test.col)
}
}
}

38
src/cmd/compile/internal/syntax/scanner.go
View File

@ -577,6 +577,7 @@ func (s *scanner) skipLine(r rune) {
func (s *scanner) lineComment() {
r := s.getr()
// directives must start at the beginning of the line (s.col == colbase)
if s.col != colbase || s.pragh == nil || (r != 'g' && r != 'l') {
s.skipLine(r)
@ -608,20 +609,47 @@ func (s *scanner) lineComment() {
s.pragh(s.line, s.col+2, prefix+string(text)) // +2 since directive text starts after //
}
func (s *scanner) fullComment() {
for {
r := s.getr()
func (s *scanner) skipComment(r rune) {
for r >= 0 {
for r == '*' {
r = s.getr()
if r == '/' {
return
}
}
if r < 0 {
s.errh(s.line, s.col, "comment not terminated")
r = s.getr()
}
s.errh(s.line, s.col, "comment not terminated")
}
func (s *scanner) fullComment() {
r := s.getr()
if s.pragh == nil || r != 'l' {
s.skipComment(r)
return
}
// s.pragh != nil && r == 'l'
// recognize line directive
const prefix = "line "
for _, m := range prefix {
if r != m {
s.skipComment(r)
return
}
r = s.getr()
}
// directive text without comment ending
s.startLit()
s.skipComment(r)
text := s.stopLit()
if i := len(text) - 2; i >= 0 && text[i] == '*' && text[i+1] == '/' {
text = text[:i]
}
s.pragh(s.line, s.col+2, prefix+string(text)) // +2 since directive text starts after /*
}
func (s *scanner) escape(quote rune) bool {

9
src/cmd/compile/internal/syntax/scanner_test.go
View File

@ -45,10 +45,10 @@ func TestTokens(t *testing.T) {
// make source
var buf bytes.Buffer
for i, s := range sampleTokens {
buf.WriteString("\t\t\t\t"[:i&3]) // leading indentation
buf.WriteString(s.src) // token
buf.WriteString(" "[:i&7]) // trailing spaces
buf.WriteString("/* foo */ // bar\n") // comments
buf.WriteString("\t\t\t\t"[:i&3]) // leading indentation
buf.WriteString(s.src) // token
buf.WriteString(" "[:i&7]) // trailing spaces
buf.WriteString("/*line foo:1 */ // bar\n") // comments (don't crash w/o directive handler)
}
// scan source
@ -314,7 +314,6 @@ func TestScanErrors(t *testing.T) {
{"`foo", "string not terminated", 0, 0},
{"/*/", "comment not terminated", 0, 0},
{"/*\n\nfoo", "comment not terminated", 0, 0},
{"/*\n\nfoo", "comment not terminated", 0, 0},
{`"\`, "string not terminated", 0, 0},
{`"\"`, "string not terminated", 0, 0},
{`"\x`, "string not terminated", 0, 0},