diff options
author | Robert Griesemer <gri@golang.org> | 2018-02-26 17:35:29 -0800 |
---|---|---|
committer | Robert Griesemer <gri@golang.org> | 2018-02-28 03:51:23 +0000 |
commit | 0c884d0810285ffec6ed6290dc64f2fa34248a19 (patch) | |
tree | c716a862891d556041f481e7be6ed145f4bf72c9 /src/cmd/compile/internal/syntax/pos.go | |
parent | b5bd5bfbc731c033955a0d4777ca34a9ac71020c (diff) | |
download | go-0c884d0810285ffec6ed6290dc64f2fa34248a19.tar.gz go-0c884d0810285ffec6ed6290dc64f2fa34248a19.zip |
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>
Diffstat (limited to 'src/cmd/compile/internal/syntax/pos.go')
-rw-r--r-- | src/cmd/compile/internal/syntax/pos.go | 63 |
1 files changed, 55 insertions, 8 deletions
diff --git a/src/cmd/compile/internal/syntax/pos.go b/src/cmd/compile/internal/syntax/pos.go index 00e603e8d3..c683c7fcfc 100644 --- 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 |