cmd/compile, cmd/compile/internal/syntax: print relative column info

This change enables printing of relative column information if a
prior line directive specified a valid column. If there was no
line directive, or the line directive didn't specify a column
(or the -C flag is specified), no column information is shown in
file positions.

Implementation: Column values (and line values, for that matter)
that are zero are interpreted as "unknown". A line directive that
doesn't specify a column records that as a zero column in the
respective PosBase data structure. When computing relative columns,
a relative value is zero of the base's column value is zero.
When formatting a position, a zero column value is not printed.

To make this work without special cases, the PosBase for a file
is given a concrete (non-0:0) position 1:1 with the PosBase's
line and column also being 1:1. In other words, at the position
1:1 of a file, it's relative positions are starting with 1:1 as
one would expect.

In the package syntax, this requires self-recursive PosBases for
file bases, matching what cmd/internal/src.PosBase was already
doing. In src.PosBase, file and inlining bases also need to be
based at 1:1 to indicate "known" positions.

This change completes the cmd/compiler part of the issue below.

Fixes #22662.

Change-Id: I6c3d2dee26709581fba0d0261b1d12e93f1cba1a
Reviewed-on: https://go-review.googlesource.com/97375
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index 78655502934b4ef6e8340e5e5a258ae332593710..e911ac6e423c35c64b260b66ca49030f04fe5982 100644 (file)
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -78,13 +78,13 @@ func (p *noder) makeSrcPosBase(b0 *syntax.PosBase) *src.PosBase {
        b1, ok := p.basemap[b0]
        if !ok {
                fn := b0.Filename()
-               if p0 := b0.Pos(); p0.IsKnown() {
+               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())
-               } else {
-                       // file base
-                       b1 = src.NewFileBase(fn, absFilename(fn))
                }
                p.basemap[b0] = b1
        }

diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go
index 3bed97b31cb7c1a3aeae11eec13be271570ff007..db0fb39c8c0e45a82c5a0d973a76b7db2140f4dd 100644 (file)
--- a/src/cmd/compile/internal/syntax/parser.go
+++ b/src/cmd/compile/internal/syntax/parser.go
@@ -85,8 +85,8 @@ func (p *parser) init(file *PosBase, r io.Reader, errh ErrorHandler, pragh Pragm
 
 // updateBase sets the current position base to a new line base at pos.
 // The base's filename, line, and column values are extracted from text
-// which is positioned at (line, col) (only needed for error messages).
-func (p *parser) updateBase(pos Pos, line, col uint, text string) {
+// which is positioned at (tline, tcol) (only needed for error messages).
+func (p *parser) updateBase(pos Pos, tline, tcol uint, text string) {
        i, n, ok := trailingDigits(text)
        if i == 0 {
                return // ignore (not a line directive)
@@ -95,38 +95,39 @@ func (p *parser) updateBase(pos Pos, line, col uint, text string) {
 
        if !ok {
                // text has a suffix :xxx but xxx is not a number
-               p.errorAt(p.posAt(line, col+i), "invalid line number: "+text[i:])
+               p.errorAt(p.posAt(tline, tcol+i), "invalid line number: "+text[i:])
                return
        }
 
+       var line, col uint
        i2, n2, ok2 := trailingDigits(text[:i-1])
        if ok2 {
                //line filename:line:col
                i, i2 = i2, i
-               n, n2 = n2, n
-               if n2 == 0 || n2 > PosMax {
-                       p.errorAt(p.posAt(line, col+i2), "invalid column number: "+text[i2:])
+               line, col = n2, n
+               if col == 0 || col > PosMax {
+                       p.errorAt(p.posAt(tline, tcol+i2), "invalid column number: "+text[i2:])
                        return
                }
-               text = text[:i2-1] // lop off :col
+               text = text[:i2-1] // lop off ":col"
        } else {
                //line filename:line
-               n2 = colbase // use start of line for column
+               line = n
        }
 
-       if n == 0 || n > PosMax {
-               p.errorAt(p.posAt(line, col+i), "invalid line number: "+text[i:])
+       if line == 0 || line > PosMax {
+               p.errorAt(p.posAt(tline, tcol+i), "invalid line number: "+text[i:])
                return
        }
 
        // If we have a column (//line filename:line:col form),
        // an empty filename means to use the previous filename.
-       filename := text[:i-1] // lop off :line
+       filename := text[:i-1] // lop off ":line"
        if filename == "" && ok2 {
                filename = p.base.Filename()
        }
 
-       p.base = NewLineBase(pos, filename, n, n2)
+       p.base = NewLineBase(pos, filename, line, col)
 }
 
 func commentText(s string) string {

diff --git a/src/cmd/compile/internal/syntax/parser_test.go b/src/cmd/compile/internal/syntax/parser_test.go
index c253a5c345a83dd890f6a17c6162a339622d4d9f..3cf55defc774dc2147d2b665343c8456866e8c95 100644 (file)
--- a/src/cmd/compile/internal/syntax/parser_test.go
+++ b/src/cmd/compile/internal/syntax/parser_test.go
@@ -193,113 +193,113 @@ func TestLineDirectives(t *testing.T) {
        for _, test := range []struct {
                src, msg  string
                filename  string
-               line, col uint // 0-based
+               line, col uint // 1-based; 0 means unknown
        }{
                // ignored //line directives
-               {"//\n", valid, filename, 1, 0},            // no directive
-               {"//line\n", valid, filename, 1, 0},        // missing colon
-               {"//line foo\n", valid, filename, 1, 0},    // missing colon
-               {"  //line foo:\n", valid, filename, 1, 0}, // not a line start
-               {"//  line foo:\n", valid, filename, 1, 0}, // space between // and line
+               {"//\n", valid, filename, 2, 1},            // no directive
+               {"//line\n", valid, filename, 2, 1},        // missing colon
+               {"//line foo\n", valid, filename, 2, 1},    // missing colon
+               {"  //line foo:\n", valid, filename, 2, 1}, // not a line start
+               {"//  line foo:\n", valid, filename, 2, 1}, // space between // and line
 
                // invalid //line directives with one colon
-               {"//line :\n", "invalid line number: ", filename, 0, 8},
-               {"//line :x\n", "invalid line number: x", filename, 0, 8},
-               {"//line foo :\n", "invalid line number: ", filename, 0, 12},
-               {"//line foo:x\n", "invalid line number: x", filename, 0, 11},
-               {"//line foo:0\n", "invalid line number: 0", filename, 0, 11},
-               {"//line foo:1 \n", "invalid line number: 1 ", filename, 0, 11},
-               {"//line foo:-12\n", "invalid line number: -12", filename, 0, 11},
-               {"//line C:foo:0\n", "invalid line number: 0", filename, 0, 13},
-               {fmt.Sprintf("//line foo:%d\n", tooLarge), fmt.Sprintf("invalid line number: %d", tooLarge), filename, 0, 11},
+               {"//line :\n", "invalid line number: ", filename, 1, 9},
+               {"//line :x\n", "invalid line number: x", filename, 1, 9},
+               {"//line foo :\n", "invalid line number: ", filename, 1, 13},
+               {"//line foo:x\n", "invalid line number: x", filename, 1, 12},
+               {"//line foo:0\n", "invalid line number: 0", filename, 1, 12},
+               {"//line foo:1 \n", "invalid line number: 1 ", filename, 1, 12},
+               {"//line foo:-12\n", "invalid line number: -12", filename, 1, 12},
+               {"//line C:foo:0\n", "invalid line number: 0", filename, 1, 14},
+               {fmt.Sprintf("//line foo:%d\n", tooLarge), fmt.Sprintf("invalid line number: %d", tooLarge), filename, 1, 12},
 
                // invalid //line directives with two colons
-               {"//line ::\n", "invalid line number: ", filename, 0, 9},
-               {"//line ::x\n", "invalid line number: x", filename, 0, 9},
-               {"//line foo::123abc\n", "invalid line number: 123abc", filename, 0, 12},
-               {"//line foo::0\n", "invalid line number: 0", filename, 0, 12},
-               {"//line foo:0:1\n", "invalid line number: 0", filename, 0, 11},
+               {"//line ::\n", "invalid line number: ", filename, 1, 10},
+               {"//line ::x\n", "invalid line number: x", filename, 1, 10},
+               {"//line foo::123abc\n", "invalid line number: 123abc", filename, 1, 13},
+               {"//line foo::0\n", "invalid line number: 0", filename, 1, 13},
+               {"//line foo:0:1\n", "invalid line number: 0", filename, 1, 12},
 
-               {"//line :123:0\n", "invalid column number: 0", filename, 0, 12},
-               {"//line foo:123:0\n", "invalid column number: 0", filename, 0, 15},
-               {fmt.Sprintf("//line foo:10:%d\n", tooLarge), fmt.Sprintf("invalid column number: %d", tooLarge), filename, 0, 14},
+               {"//line :123:0\n", "invalid column number: 0", filename, 1, 13},
+               {"//line foo:123:0\n", "invalid column number: 0", filename, 1, 16},
+               {fmt.Sprintf("//line foo:10:%d\n", tooLarge), fmt.Sprintf("invalid column number: %d", tooLarge), filename, 1, 15},
 
                // effect of valid //line directives on lines
-               {"//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 /src/a/a.go:123\n   foo", valid, "/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", 0, 0},
-               {"//line foo :123:1\n", valid, "foo ", 123 - linebase, 0},
-               {"//line ::123\n", valid, ":", 123 - linebase, 0},
+               {"//line foo:123\n   foo", valid, "foo", 123, 0},
+               {"//line  foo:123\n   foo", valid, " foo", 123, 0},
+               {"//line foo:123\n//line bar:345\nfoo", valid, "bar", 345, 0},
+               {"//line C:foo:123\n", valid, "C:foo", 123, 0},
+               {"//line /src/a/a.go:123\n   foo", valid, "/src/a/a.go", 123, 0},
+               {"//line :x:1\n", valid, ":x", 1, 0},
+               {"//line foo ::1\n", valid, "foo :", 1, 0},
+               {"//line foo:123abc:1\n", valid, "foo:123abc", 1, 0},
+               {"//line foo :123:1\n", valid, "foo ", 123, 1},
+               {"//line ::123\n", valid, ":", 123, 0},
 
                // effect of valid //line directives on columns
-               {"//line :x:1:10\n", valid, ":x", 1 - linebase, 10 - colbase},
-               {"//line foo ::1:2\n", valid, "foo :", 1 - linebase, 2 - colbase},
-               {"//line foo:123abc:1:1000\n", valid, "foo:123abc", 1 - linebase, 1000 - colbase},
-               {"//line foo :123:1000\n\n", valid, "foo ", 124 - linebase, 0},
-               {"//line ::123:1234\n", valid, ":", 123 - linebase, 1234 - colbase},
+               {"//line :x:1:10\n", valid, ":x", 1, 10},
+               {"//line foo ::1:2\n", valid, "foo :", 1, 2},
+               {"//line foo:123abc:1:1000\n", valid, "foo:123abc", 1, 1000},
+               {"//line foo :123:1000\n\n", valid, "foo ", 124, 1},
+               {"//line ::123:1234\n", valid, ":", 123, 1234},
 
                // //line directives with omitted filenames lead to empty filenames
-               {"//line :10\n", valid, "", 10 - linebase, 0},
-               {"//line :10:20\n", valid, filename, 10 - linebase, 20 - colbase},
-               {"//line bar:1\n//line :10\n", valid, "", 10 - linebase, 0},
-               {"//line bar:1\n//line :10:20\n", valid, "bar", 10 - linebase, 20 - colbase},
+               {"//line :10\n", valid, "", 10, 0},
+               {"//line :10:20\n", valid, filename, 10, 20},
+               {"//line bar:1\n//line :10\n", valid, "", 10, 0},
+               {"//line bar:1\n//line :10:20\n", valid, "bar", 10, 20},
 
                // ignored /*line directives
-               {"/**/", valid, filename, 0, 4},             // no directive
-               {"/*line*/", valid, filename, 0, 8},         // missing colon
-               {"/*line foo*/", valid, filename, 0, 12},    // missing colon
-               {"  //line foo:*/", valid, filename, 0, 15}, // not a line start
-               {"/*  line foo:*/", valid, filename, 0, 15}, // space between // and line
+               {"/**/", valid, filename, 1, 5},             // no directive
+               {"/*line*/", valid, filename, 1, 9},         // missing colon
+               {"/*line foo*/", valid, filename, 1, 13},    // missing colon
+               {"  //line foo:*/", valid, filename, 1, 16}, // not a line start
+               {"/*  line foo:*/", valid, filename, 1, 16}, // space between // and line
 
                // invalid /*line directives with one colon
-               {"/*line :*/", "invalid line number: ", filename, 0, 8},
-               {"/*line :x*/", "invalid line number: x", filename, 0, 8},
-               {"/*line foo :*/", "invalid line number: ", filename, 0, 12},
-               {"/*line foo:x*/", "invalid line number: x", filename, 0, 11},
-               {"/*line foo:0*/", "invalid line number: 0", filename, 0, 11},
-               {"/*line foo:1 */", "invalid line number: 1 ", filename, 0, 11},
-               {"/*line C:foo:0*/", "invalid line number: 0", filename, 0, 13},
-               {fmt.Sprintf("/*line foo:%d*/", tooLarge), fmt.Sprintf("invalid line number: %d", tooLarge), filename, 0, 11},
+               {"/*line :*/", "invalid line number: ", filename, 1, 9},
+               {"/*line :x*/", "invalid line number: x", filename, 1, 9},
+               {"/*line foo :*/", "invalid line number: ", filename, 1, 13},
+               {"/*line foo:x*/", "invalid line number: x", filename, 1, 12},
+               {"/*line foo:0*/", "invalid line number: 0", filename, 1, 12},
+               {"/*line foo:1 */", "invalid line number: 1 ", filename, 1, 12},
+               {"/*line C:foo:0*/", "invalid line number: 0", filename, 1, 14},
+               {fmt.Sprintf("/*line foo:%d*/", tooLarge), fmt.Sprintf("invalid line number: %d", tooLarge), filename, 1, 12},
 
                // invalid /*line directives with two colons
-               {"/*line ::*/", "invalid line number: ", filename, 0, 9},
-               {"/*line ::x*/", "invalid line number: x", filename, 0, 9},
-               {"/*line foo::123abc*/", "invalid line number: 123abc", filename, 0, 12},
-               {"/*line foo::0*/", "invalid line number: 0", filename, 0, 12},
-               {"/*line foo:0:1*/", "invalid line number: 0", filename, 0, 11},
+               {"/*line ::*/", "invalid line number: ", filename, 1, 10},
+               {"/*line ::x*/", "invalid line number: x", filename, 1, 10},
+               {"/*line foo::123abc*/", "invalid line number: 123abc", filename, 1, 13},
+               {"/*line foo::0*/", "invalid line number: 0", filename, 1, 13},
+               {"/*line foo:0:1*/", "invalid line number: 0", filename, 1, 12},
 
-               {"/*line :123:0*/", "invalid column number: 0", filename, 0, 12},
-               {"/*line foo:123:0*/", "invalid column number: 0", filename, 0, 15},
-               {fmt.Sprintf("/*line foo:10:%d*/", tooLarge), fmt.Sprintf("invalid column number: %d", tooLarge), filename, 0, 14},
+               {"/*line :123:0*/", "invalid column number: 0", filename, 1, 13},
+               {"/*line foo:123:0*/", "invalid column number: 0", filename, 1, 16},
+               {fmt.Sprintf("/*line foo:10:%d*/", tooLarge), fmt.Sprintf("invalid column number: %d", tooLarge), filename, 1, 15},
 
                // effect of valid /*line directives on lines
-               {"/*line foo:123*/   foo", valid, "foo", 123 - linebase, 3},
-               {"/*line foo:123*/\n//line bar:345\nfoo", valid, "bar", 345 - linebase, 0},
-               {"/*line C:foo:123*/", valid, "C:foo", 123 - linebase, 0},
-               {"/*line /src/a/a.go:123*/   foo", valid, "/src/a/a.go", 123 - linebase, 3},
-               {"/*line :x:1*/", valid, ":x", 1 - linebase, 0},
-               {"/*line foo ::1*/", valid, "foo :", 1 - linebase, 0},
-               {"/*line foo:123abc:1*/", valid, "foo:123abc", 1 - linebase, 0},
-               {"/*line foo :123:10*/", valid, "foo ", 123 - linebase, 10 - colbase},
-               {"/*line ::123*/", valid, ":", 123 - linebase, 0},
+               {"/*line foo:123*/   foo", valid, "foo", 123, 0},
+               {"/*line foo:123*/\n//line bar:345\nfoo", valid, "bar", 345, 0},
+               {"/*line C:foo:123*/", valid, "C:foo", 123, 0},
+               {"/*line /src/a/a.go:123*/   foo", valid, "/src/a/a.go", 123, 0},
+               {"/*line :x:1*/", valid, ":x", 1, 0},
+               {"/*line foo ::1*/", valid, "foo :", 1, 0},
+               {"/*line foo:123abc:1*/", valid, "foo:123abc", 1, 0},
+               {"/*line foo :123:10*/", valid, "foo ", 123, 10},
+               {"/*line ::123*/", valid, ":", 123, 0},
 
                // effect of valid /*line directives on columns
-               {"/*line :x:1:10*/", valid, ":x", 1 - linebase, 10 - colbase},
-               {"/*line foo ::1:2*/", valid, "foo :", 1 - linebase, 2 - colbase},
-               {"/*line foo:123abc:1:1000*/", valid, "foo:123abc", 1 - linebase, 1000 - colbase},
-               {"/*line foo :123:1000*/\n", valid, "foo ", 124 - linebase, 0},
-               {"/*line ::123:1234*/", valid, ":", 123 - linebase, 1234 - colbase},
+               {"/*line :x:1:10*/", valid, ":x", 1, 10},
+               {"/*line foo ::1:2*/", valid, "foo :", 1, 2},
+               {"/*line foo:123abc:1:1000*/", valid, "foo:123abc", 1, 1000},
+               {"/*line foo :123:1000*/\n", valid, "foo ", 124, 1},
+               {"/*line ::123:1234*/", valid, ":", 123, 1234},
 
                // /*line directives with omitted filenames lead to the previously used filenames
-               {"/*line :10*/", valid, "", 10 - linebase, 0},
-               {"/*line :10:20*/", valid, filename, 10 - linebase, 20 - colbase},
-               {"//line bar:1\n/*line :10*/", valid, "", 10 - linebase, 0},
-               {"//line bar:1\n/*line :10:20*/", valid, "bar", 10 - linebase, 20 - colbase},
+               {"/*line :10*/", valid, "", 10, 0},
+               {"/*line :10:20*/", valid, filename, 10, 20},
+               {"//line bar:1\n/*line :10*/", valid, "", 10, 0},
+               {"//line bar:1\n/*line :10:20*/", valid, "bar", 10, 20},
        } {
                base := NewFileBase(filename)
                _, err := Parse(base, strings.NewReader(test.src), nil, nil, 0)
@@ -320,11 +320,11 @@ func TestLineDirectives(t *testing.T) {
                if filename := pos.RelFilename(); filename != test.filename {
                        t.Errorf("%s: got filename = %q; want %q", test.src, filename, test.filename)
                }
-               if line := pos.RelLine(); line != test.line+linebase {
-                       t.Errorf("%s: got line = %d; want %d", test.src, line, test.line+linebase)
+               if line := pos.RelLine(); line != test.line {
+                       t.Errorf("%s: got line = %d; want %d", test.src, line, test.line)
                }
-               if col := pos.RelCol(); col != test.col+colbase {
-                       t.Errorf("%s: got col = %d; want %d", test.src, col, test.col+colbase)
+               if col := pos.RelCol(); col != test.col {
+                       t.Errorf("%s: got col = %d; want %d", test.src, col, test.col)
                }
        }
 }

diff --git a/src/cmd/compile/internal/syntax/pos.go b/src/cmd/compile/internal/syntax/pos.go
index 00e603e8d3bf181400baf42faac9c59a3e7083b9..c683c7fcfc1fbde013bb5f14f5220c2ac1cca9af 100644 (file)
--- a/src/cmd/compile/internal/syntax/pos.go
+++ b/src/cmd/compile/internal/syntax/pos.go
@@ -31,10 +31,26 @@ func (pos Pos) Base() *PosBase { return pos.base }
 func (pos Pos) Line() uint     { return uint(pos.line) }
 func (pos Pos) Col() uint      { return uint(pos.col) }
 
-func (pos Pos) RelFilename() string { b := pos.Base(); return b.Filename() }
-func (pos Pos) RelLine() uint       { b := pos.Base(); return b.Line() + (pos.Line() - b.Pos().Line()) }
+func (pos Pos) RelFilename() string { return pos.base.Filename() }
+
+func (pos Pos) RelLine() uint {
+       b := pos.base
+       if b.Line() == 0 {
+               // base line is unknown => relative line is unknown
+               return 0
+       }
+       return b.Line() + (pos.Line() - b.Pos().Line())
+}
+
 func (pos Pos) RelCol() uint {
-       b := pos.Base()
+       b := pos.base
+       if b.Col() == 0 {
+               // base column is unknown => relative column is unknown
+               // (the current specification for line directives requires
+               // this to apply until the next PosBase/line directive,
+               // not just until the new newline)
+               return 0
+       }
        if pos.Line() == b.Pos().Line() {
                // pos on same line as pos base => column is relative to pos base
                return b.Col() + (pos.Col() - b.Pos().Col())
@@ -43,13 +59,34 @@ func (pos Pos) RelCol() uint {
 }
 
 func (pos Pos) String() string {
-       s := fmt.Sprintf("%s:%d:%d", pos.RelFilename(), pos.RelLine(), pos.RelCol())
-       if bpos := pos.Base().Pos(); bpos.IsKnown() {
-               s += fmt.Sprintf("[%s:%d:%d]", bpos.RelFilename(), pos.Line(), pos.Col())
+       rel := position_{pos.RelFilename(), pos.RelLine(), pos.RelCol()}
+       abs := position_{pos.Base().Pos().RelFilename(), pos.Line(), pos.Col()}
+       s := rel.String()
+       if rel != abs {
+               s += "[" + abs.String() + "]"
        }
        return s
 }
 
+// TODO(gri) cleanup: find better name, avoid conflict with position in error_test.go
+type position_ struct {
+       filename  string
+       line, col uint
+}
+
+func (p position_) String() string {
+       if p.line == 0 {
+               if p.filename == "" {
+                       return "<unknown position>"
+               }
+               return p.filename
+       }
+       if p.col == 0 {
+               return fmt.Sprintf("%s:%d", p.filename, p.line)
+       }
+       return fmt.Sprintf("%s:%d:%d", p.filename, p.line, p.col)
+}
+
 // A PosBase represents the base for relative position information:
 // At position pos, the relative position is filename:line:col.
 type PosBase struct {
@@ -59,9 +96,12 @@ type PosBase struct {
 }
 
 // NewFileBase returns a new PosBase for the given filename.
-// The PosBase position is unknown in this case.
+// A file PosBase's position is relative to itself, with the
+// position being filename:1:1.
 func NewFileBase(filename string) *PosBase {
-       return &PosBase{filename: filename}
+       base := &PosBase{MakePos(nil, linebase, colbase), filename, linebase, colbase}
+       base.pos.base = base
+       return base
 }
 
 // NewLineBase returns a new PosBase for a line directive "line filename:line:col"
@@ -73,6 +113,13 @@ func NewLineBase(pos Pos, filename string, line, col uint) *PosBase {
        return &PosBase{pos, filename, sat32(line), sat32(col)}
 }
 
+func (base *PosBase) IsFileBase() bool {
+       if base == nil {
+               return false
+       }
+       return base.pos.base == base
+}
+
 func (base *PosBase) Pos() (_ Pos) {
        if base == nil {
                return

diff --git a/src/cmd/internal/src/pos.go b/src/cmd/internal/src/pos.go
index ca7a10e955e47182e995a7c8eee4913b7590d312..c7b9a8069d187234b90653390c5e7761d47adbbd 100644 (file)
--- a/src/cmd/internal/src/pos.go
+++ b/src/cmd/internal/src/pos.go
@@ -69,14 +69,28 @@ func (p *Pos) SetBase(base *PosBase) { p.base = base }
 func (p Pos) RelFilename() string { return p.base.Filename() }
 
 // RelLine returns the line number relative to the position'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
+       if b.Line() == 0 {
+               // base line is unknown => relative line is unknown
+               return 0
+       }
+       return b.Line() + (p.Line() - b.Pos().Line())
+}
 
 // RelCol returns the column number relative to the position's base.
 func (p Pos) RelCol() uint {
-       b := p.Base()
+       b := p.base
+       if b.Col() == 0 {
+               // base column is unknown => relative column is unknown
+               // (the current specification for line directives requires
+               // this to apply until the next PosBase/line directive,
+               // not just until the new newline)
+               return 0
+       }
        if p.Line() == b.Pos().Line() {
                // p on same line as p's base => column is relative to p's base
-               return b.Col() + p.Col() - b.Pos().Col()
+               return b.Col() + (p.Col() - b.Pos().Col())
        }
        return p.Col()
 }
@@ -93,10 +107,10 @@ func (p Pos) String() string {
 }
 
 // Format formats a position as "filename:line" or "filename:line:column",
-// controlled by the showCol flag. A position relative to a line directive
-// is always formatted without column information. In that case, if showOrig
-// is set, the original position (again controlled by showCol) is appended
-// in square brackets: "filename:line[origfile:origline:origcolumn]".
+// controlled by the showCol flag and if the column is known (!= 0).
+// For positions relative to line directives, the original position is
+// shown as well, as in "filename:line[origfile:origline:origcolumn] if
+// showOrig is set.
 func (p Pos) Format(showCol, showOrig bool) string {
        if !p.IsKnown() {
                return "<unknown line number>"
@@ -107,9 +121,6 @@ func (p Pos) Format(showCol, showOrig bool) string {
                return format(p.Filename(), p.Line(), p.Col(), showCol)
        }
 
-       // TODO(gri): Column information should be printed if a line
-       // directive explicitly specified a column, per issue #22662.
-
        // base is relative
        // Print the column only for the original position since the
        // relative position's column information may be bogus (it's
@@ -118,7 +129,7 @@ func (p Pos) Format(showCol, showOrig bool) string {
        // that's provided via a line directive).
        // TODO(gri) This may not be true if we have an inlining base.
        // We may want to differentiate at some point.
-       s := format(p.RelFilename(), p.RelLine(), 0, false)
+       s := format(p.RelFilename(), p.RelLine(), p.RelCol(), showCol)
        if showOrig {
                s += "[" + format(p.Filename(), p.Line(), p.Col(), showCol) + "]"
        }
@@ -126,11 +137,11 @@ func (p Pos) Format(showCol, showOrig bool) string {
 }
 
 // format formats a (filename, line, col) tuple as "filename:line" (showCol
-// is false) or "filename:line:column" (showCol is true).
+// is false or col == 0) or "filename:line:column" (showCol is true and col != 0).
 func format(filename string, line, col uint, showCol bool) string {
        s := filename + ":" + strconv.FormatUint(uint64(line), 10)
-       // col == colMax is interpreted as unknown column value
-       if showCol && col < colMax {
+       // col == 0 and col == colMax are interpreted as unknown column values
+       if showCol && 0 < col && col < colMax {
                s += ":" + strconv.FormatUint(uint64(col), 10)
        }
        return s
@@ -141,8 +152,6 @@ func format(filename string, line, col uint, showCol bool) string {
 
 // A PosBase encodes a filename and base position.
 // Typically, each file and line directive introduce a PosBase.
-// A nil *PosBase is a ready to use file PosBase for an unnamed
-// file with line numbers starting at 1.
 type PosBase struct {
        pos         Pos    // position at which the relative position is (line, col)
        filename    string // file name used to open source file, for error messages
@@ -155,17 +164,16 @@ type PosBase struct {
 // NewFileBase returns a new *PosBase for a file with the given (relative and
 // absolute) filenames.
 func NewFileBase(filename, absFilename string) *PosBase {
-       if filename != "" {
-               base := &PosBase{
-                       filename:    filename,
-                       absFilename: absFilename,
-                       symFilename: FileSymPrefix + absFilename,
-                       inl:         -1,
-               }
-               base.pos = MakePos(base, 0, 0)
-               return base
+       base := &PosBase{
+               filename:    filename,
+               absFilename: absFilename,
+               symFilename: FileSymPrefix + absFilename,
+               line:        1,
+               col:         1,
+               inl:         -1,
        }
-       return nil
+       base.pos = MakePos(base, 1, 1)
+       return base
 }
 
 // NewLinePragmaBase returns a new *PosBase for a line directive of the form
@@ -180,8 +188,8 @@ func NewLinePragmaBase(pos Pos, filename, absFilename string, line, col uint) *P
 // index. If old == nil, the resulting PosBase has no filename.
 func NewInliningBase(old *PosBase, inlTreeIndex int) *PosBase {
        if old == nil {
-               base := &PosBase{inl: inlTreeIndex}
-               base.pos = MakePos(base, 0, 0)
+               base := &PosBase{line: 1, col: 1, inl: inlTreeIndex}
+               base.pos = MakePos(base, 1, 1)
                return base
        }
        copy := *old

diff --git a/src/cmd/internal/src/pos_test.go b/src/cmd/internal/src/pos_test.go
index 1cebf6f0f66efe7769f018e39a7a362968cf4f25..3fea45c11672981400801efda587981e9a6b4dd3 100644 (file)
--- a/src/cmd/internal/src/pos_test.go
+++ b/src/cmd/internal/src/pos_test.go
@@ -39,23 +39,23 @@ func TestPos(t *testing.T) {
                relLine, relCol uint
        }{
                {Pos{}, "<unknown line number>", "", 0, 0, "", 0, 0},
-               {MakePos(nil, 2, 3), ":2:3", "", 2, 3, "", 2, 3},
+               {MakePos(nil, 2, 3), ":2:3", "", 2, 3, "", 0, 0},
                {MakePos(f0, 2, 3), ":2:3", "", 2, 3, "", 2, 3},
                {MakePos(f1, 1, 1), "f1:1:1", "f1", 1, 1, "f1", 1, 1},
-               {MakePos(f2, 7, 10), "f2:17[:7:10]", "", 7, 10, "f2", 17, 10},
-               {MakePos(f3, 12, 7), "f3:102[f1:12:7]", "f1", 12, 7, "f3", 102, 7},
-               {MakePos(f4, 25, 1), "f4:115[f3:25:1]", "f3", 25, 1, "f4", 115, 1},
+               {MakePos(f2, 7, 10), "f2:17[:7:10]", "", 7, 10, "f2", 17, 0 /* line base doesn't specify a column */},
+               {MakePos(f3, 12, 7), "f3:102:7[f1:12:7]", "f1", 12, 7, "f3", 102, 7},
+               {MakePos(f4, 25, 1), "f4:115:1[f3:25:1]", "f3", 25, 1, "f4", 115, 1},
 
                // line directives with non-1 columns
-               {MakePos(f5, 5, 5), "f5:10[f1:5:5]", "f1", 5, 5, "f5", 10, 1},
-               {MakePos(f5, 5, 10), "f5:10[f1:5:10]", "f1", 5, 10, "f5", 10, 6},
-               {MakePos(f5, 6, 10), "f5:11[f1:6:10]", "f1", 6, 10, "f5", 11, 10},
+               {MakePos(f5, 5, 5), "f5:10:1[f1:5:5]", "f1", 5, 5, "f5", 10, 1},
+               {MakePos(f5, 5, 10), "f5:10:6[f1:5:10]", "f1", 5, 10, "f5", 10, 6},
+               {MakePos(f5, 6, 10), "f5:11:10[f1:6:10]", "f1", 6, 10, "f5", 11, 10},
 
                // positions from issue #19392
-               {MakePos(fc, 4, 1), "c.go:10[p.go:4:1]", "p.go", 4, 1, "c.go", 10, 1},
-               {MakePos(ft, 7, 1), "t.go:20[p.go:7:1]", "p.go", 7, 1, "t.go", 20, 1},
-               {MakePos(fv, 10, 1), "v.go:30[p.go:10:1]", "p.go", 10, 1, "v.go", 30, 1},
-               {MakePos(ff, 13, 1), "f.go:40[p.go:13:1]", "p.go", 13, 1, "f.go", 40, 1},
+               {MakePos(fc, 4, 1), "c.go:10:1[p.go:4:1]", "p.go", 4, 1, "c.go", 10, 1},
+               {MakePos(ft, 7, 1), "t.go:20:1[p.go:7:1]", "p.go", 7, 1, "t.go", 20, 1},
+               {MakePos(fv, 10, 1), "v.go:30:1[p.go:10:1]", "p.go", 10, 1, "v.go", 30, 1},
+               {MakePos(ff, 13, 1), "f.go:40:1[p.go:13:1]", "p.go", 13, 1, "f.go", 40, 1},
        } {
                pos := test.pos
                if got := pos.String(); got != test.string {
@@ -134,10 +134,10 @@ func TestLico(t *testing.T) {
                string    string
                line, col uint
        }{
-               {0, ":0:0", 0, 0},
-               {makeLico(0, 0), ":0:0", 0, 0},
+               {0, ":0", 0, 0},
+               {makeLico(0, 0), ":0", 0, 0},
                {makeLico(0, 1), ":0:1", 0, 1},
-               {makeLico(1, 0), ":1:0", 1, 0},
+               {makeLico(1, 0), ":1", 1, 0},
                {makeLico(1, 1), ":1:1", 1, 1},
                {makeLico(2, 3), ":2:3", 2, 3},
                {makeLico(lineMax, 1), fmt.Sprintf(":%d:1", lineMax), lineMax, 1},

diff --git a/test/fixedbugs/issue22662b.go b/test/fixedbugs/issue22662b.go
new file mode 100644 (file)
index 0000000..42c2a80
--- /dev/null
+++ b/test/fixedbugs/issue22662b.go
@@ -0,0 +1,65 @@
+// run
+
+// Copyright 2018 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.
+
+// Verify the impact of line directives on error positions and position formatting.
+
+package main
+
+import (
+       "io/ioutil"
+       "log"
+       "os"
+       "os/exec"
+       "runtime"
+       "strings"
+)
+
+// Each of these tests is expected to fail (missing package clause)
+// at the position determined by the preceeding line directive.
+var tests = []struct {
+       src, pos string
+}{
+       {"//line :10\n", ":10:"},                   // no filename means no filename
+       {"//line :10:4\n", "filename:10:4"},        // no filename means use existing filename
+       {"//line foo.go:10\n", "foo.go:10:"},       // no column means don't print a column
+       {"//line foo.go:10:4\n", "foo.go:10:4:"},   // column means print a column
+       {"//line foo.go:10:4\n\n", "foo.go:11:1:"}, // relative columns start at 1 after newline
+
+       {"/*line :10*/", ":10:"},
+       {"/*line :10:4*/", "filename:10:4"},
+       {"/*line foo.go:10*/", "foo.go:10:"},
+       {"/*line foo.go:10:4*/", "foo.go:10:4:"},
+       {"/*line foo.go:10:4*/\n", "foo.go:11:1:"},
+}
+
+func main() {
+       if runtime.GOOS == "nacl" {
+               return // no file system available on builders
+       }
+
+       f, err := ioutil.TempFile("", "issue22662b.go")
+       if err != nil {
+               log.Fatal(err)
+       }
+       f.Close()
+       defer os.Remove(f.Name())
+
+       for _, test := range tests {
+               if err := ioutil.WriteFile(f.Name(), []byte(test.src), 0660); err != nil {
+                       log.Fatal(err)
+               }
+
+               out, err := exec.Command("go", "tool", "compile", f.Name()).CombinedOutput()
+               if err == nil {
+                       log.Fatalf("expected compiling\n---\n%s\n---\nto fail", test.src)
+               }
+
+               errmsg := strings.Replace(string(out), f.Name(), "filename", -1) // use "filename" instead of actual (long) filename
+               if !strings.HasPrefix(errmsg, test.pos) {
+                       log.Fatalf("%q: got %q; want position %q", test.src, errmsg, test.pos)
+               }
+       }
+}