[dev.inline] cmd/internal/src: replace src.Pos with syntax.Pos

This replaces the src.Pos LineHist-based position tracking with
the syntax.Pos implementation and updates all uses.

The LineHist table is not used anymore - the respective code is still
there but should be removed eventually. CL forthcoming.

Passes toolstash -cmp when comparing to the master repo (with the
exception of a couple of swapped assembly instructions, likely due
to different instruction scheduling because the line-based sorting
has changed; though this is won't affect correctness).

The sizes of various important compiler data structures have increased
significantly (see the various sizes_test.go files); this is probably
the reason for an increase of compilation times (to be addressed). Here
are the results of compilebench -count 5, run on a "quiet" machine (no
apps running besides a terminal):

name       old time/op     new time/op     delta
Template       256ms ± 1%      280ms ±15%  +9.54%          (p=0.008 n=5+5)
Unicode        132ms ± 1%      132ms ± 1%    ~             (p=0.690 n=5+5)
GoTypes        891ms ± 1%      917ms ± 2%  +2.88%          (p=0.008 n=5+5)
Compiler       3.84s ± 2%      3.99s ± 2%  +3.95%          (p=0.016 n=5+5)
MakeBash       47.1s ± 1%      47.2s ± 2%    ~             (p=0.841 n=5+5)

name       old user-ns/op  new user-ns/op  delta
Template        309M ± 1%       326M ± 2%  +5.18%          (p=0.008 n=5+5)
Unicode         165M ± 1%       168M ± 4%    ~             (p=0.421 n=5+5)
GoTypes        1.14G ± 2%      1.18G ± 1%  +3.47%          (p=0.008 n=5+5)
Compiler       5.00G ± 1%      5.16G ± 1%  +3.12%          (p=0.008 n=5+5)

Change-Id: I241c4246cdff627d7ecb95cac23060b38f9775ec
Reviewed-on: https://go-review.googlesource.com/34273
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/src/cmd/compile/internal/syntax/parser_test.go b/src/cmd/compile/internal/syntax/parser_test.go
index 23fed3b105..da56168957 100644
--- a/src/cmd/compile/internal/syntax/parser_test.go
+++ b/src/cmd/compile/internal/syntax/parser_test.go
@@ -6,6 +6,7 @@ package syntax
 
 import (
 	"bytes"
+	"cmd/internal/src"
 	"flag"
 	"fmt"
 	"io/ioutil"
@@ -18,11 +19,11 @@ import (
 )
 
 var fast = flag.Bool("fast", false, "parse package files in parallel")
-var src = flag.String("src", "parser.go", "source file to parse")
+var src_ = flag.String("src", "parser.go", "source file to parse")
 var verify = flag.Bool("verify", false, "verify idempotent printing")
 
 func TestParse(t *testing.T) {
-	_, err := ParseFile(*src, nil, nil, 0)
+	_, err := ParseFile(*src_, nil, nil, 0)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -133,7 +134,7 @@ func verifyPrint(filename string, ast1 *File) {
 		panic(err)
 	}
 
-	ast2, err := ParseBytes(filename, buf1.Bytes(), nil, nil, 0)
+	ast2, err := ParseBytes(src.NewFileBase(filename, filename), buf1.Bytes(), nil, nil, 0)
 	if err != nil {
 		panic(err)
 	}
@@ -157,7 +158,7 @@ func verifyPrint(filename string, ast1 *File) {
 }
 
 func TestIssue17697(t *testing.T) {
-	_, err := ParseBytes("", nil, nil, nil, 0) // return with parser error, don't panic
+	_, err := ParseBytes(nil, nil, nil, nil, 0) // return with parser error, don't panic
 	if err == nil {
 		t.Errorf("no error reported")
 	}
@@ -202,7 +203,7 @@ func TestLineDirectives(t *testing.T) {
 		{"//line foo:123\n   foo", "syntax error: package statement must be first", "foo", 123, 3},
 		{"//line foo:123\n//line bar:345\nfoo", "syntax error: package statement must be first", "bar", 345, 0},
 	} {
-		_, err := ParseBytes("", []byte(test.src), nil, nil, 0)
+		_, err := ParseBytes(nil, []byte(test.src), nil, nil, 0)
 		if err == nil {
 			t.Errorf("%s: no error reported", test.src)
 			continue