cmd/internal: remove duplicate pathToPrefix function

goobj.importPathToPrefix is 3x faster than gc.pathToPrefix so rename and
move it to cmd/internal/objabi which is already imported by both goobj and
gc.

Change-Id: I10eda5bce95ef6d5d888818c5c47258c2833ea45
Reviewed-on: https://go-review.googlesource.com/40875
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/fmt_test.go

@@ -606,7 +606,6 @@ var knownFormats = map[string]string{
 	"[]cmd/compile/internal/ssa.ID %v":                "",
 	"[]string %v":                                     "",
 	"bool %v":                                         "",
-	"byte %02x":                                       "",
 	"byte %08b":                                       "",
 	"byte %c":                                         "",
 	"cmd/compile/internal/arm.shift %d":               "",

src/cmd/compile/internal/gc/subr.go

@@ -5,7 +5,6 @@
 package gc
 
 import (
-	"bytes"
 	"cmd/compile/internal/types"
 	"cmd/internal/objabi"
 	"cmd/internal/src"
@@ -1958,33 +1957,6 @@ func ngotype(n *Node) *types.Sym {
 	return nil
 }
 
-// Convert raw string to the prefix that will be used in the symbol
-// table. All control characters, space, '%' and '"', as well as
-// non-7-bit clean bytes turn into %xx. The period needs escaping
-// only in the last segment of the path, and it makes for happier
-// users if we escape that as little as possible.
-//
-// If you edit this, edit ../../debug/goobj/read.go:/importPathToPrefix too.
-func pathtoprefix(s string) string {
-	slash := strings.LastIndex(s, "/")
-	for i := 0; i < len(s); i++ {
-		c := s[i]
-		if c <= ' ' || i >= slash && c == '.' || c == '%' || c == '"' || c >= 0x7F {
-			var buf bytes.Buffer
-			for i := 0; i < len(s); i++ {
-				c := s[i]
-				if c <= ' ' || i >= slash && c == '.' || c == '%' || c == '"' || c >= 0x7F {
-					fmt.Fprintf(&buf, "%%%02x", c)
-					continue
-				}
-				buf.WriteByte(c)
-			}
-			return buf.String()
-		}
-	}
-	return s
-}
-
 var pkgMap = make(map[string]*types.Pkg)
 var pkgs []*types.Pkg
 
@@ -1995,7 +1967,7 @@ func mkpkg(path string) *types.Pkg {
 
 	p := new(types.Pkg)
 	p.Path = path
-	p.Prefix = pathtoprefix(path)
+	p.Prefix = objabi.PathToPrefix(path)
 	p.Syms = make(map[string]*types.Sym)
 	pkgMap[path] = p
 	pkgs = append(pkgs, p)

src/cmd/internal/goobj/read.go

@@ -159,45 +159,6 @@ type objReader struct {
 	pkgprefix  string
 }
 
-// importPathToPrefix returns the prefix that will be used in the
-// final symbol table for the given import path.
-// We escape '%', '"', all control characters and non-ASCII bytes,
-// and any '.' after the final slash.
-//
-// See ../../../cmd/ld/lib.c:/^pathtoprefix and
-// ../../../cmd/gc/subr.c:/^pathtoprefix.
-func importPathToPrefix(s string) string {
-	// find index of last slash, if any, or else -1.
-	// used for determining whether an index is after the last slash.
-	slash := strings.LastIndex(s, "/")
-
-	// check for chars that need escaping
-	n := 0
-	for r := 0; r < len(s); r++ {
-		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
-			n++
-		}
-	}
-
-	// quick exit
-	if n == 0 {
-		return s
-	}
-
-	// escape
-	const hex = "0123456789abcdef"
-	p := make([]byte, 0, len(s)+2*n)
-	for r := 0; r < len(s); r++ {
-		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
-			p = append(p, '%', hex[c>>4], hex[c&0xF])
-		} else {
-			p = append(p, c)
-		}
-	}
-
-	return string(p)
-}
-
 // init initializes r to read package p from f.
 func (r *objReader) init(f io.ReadSeeker, p *Package) {
 	r.f = f
@@ -206,7 +167,7 @@ func (r *objReader) init(f io.ReadSeeker, p *Package) {
 	r.limit, _ = f.Seek(0, io.SeekEnd)
 	f.Seek(r.offset, io.SeekStart)
 	r.b = bufio.NewReader(f)
-	r.pkgprefix = importPathToPrefix(p.ImportPath) + "."
+	r.pkgprefix = objabi.PathToPrefix(p.ImportPath) + "."
 }
 
 // error records that an error occurred.

src/cmd/internal/goobj/read_test.go

@@ -1,28 +0,0 @@
-// Copyright 2013 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.
-
-package goobj
-
-import "testing"
-
-var importPathToPrefixTests = []struct {
-	in  string
-	out string
-}{
-	{"runtime", "runtime"},
-	{"sync/atomic", "sync/atomic"},
-	{"golang.org/x/tools/godoc", "golang.org/x/tools/godoc"},
-	{"foo.bar/baz.quux", "foo.bar/baz%2equux"},
-	{"", ""},
-	{"%foo%bar", "%25foo%25bar"},
-	{"\x01\x00\x7F☺", "%01%00%7f%e2%98%ba"},
-}
-
-func TestImportPathToPrefix(t *testing.T) {
-	for _, tt := range importPathToPrefixTests {
-		if out := importPathToPrefix(tt.in); out != tt.out {
-			t.Errorf("importPathToPrefix(%q) = %q, want %q", tt.in, out, tt.out)
-		}
-	}
-}

src/cmd/internal/objabi/path.go

@@ -0,0 +1,41 @@
+// Copyright 2017 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.
+
+package objabi
+
+import "strings"
+
+// PathToPrefix converts raw string to the prefix that will be used in the
+// symbol table. All control characters, space, '%' and '"', as well as
+// non-7-bit clean bytes turn into %xx. The period needs escaping only in the
+// last segment of the path, and it makes for happier users if we escape that as
+// little as possible.
+func PathToPrefix(s string) string {
+	slash := strings.LastIndex(s, "/")
+	// check for chars that need escaping
+	n := 0
+	for r := 0; r < len(s); r++ {
+		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
+			n++
+		}
+	}
+
+	// quick exit
+	if n == 0 {
+		return s
+	}
+
+	// escape
+	const hex = "0123456789abcdef"
+	p := make([]byte, 0, len(s)+2*n)
+	for r := 0; r < len(s); r++ {
+		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
+			p = append(p, '%', hex[c>>4], hex[c&0xF])
+		} else {
+			p = append(p, c)
+		}
+	}
+
+	return string(p)
+}

src/cmd/internal/objabi/path_test.go

@@ -0,0 +1,33 @@
+// Copyright 2017 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.
+
+package objabi
+
+import "testing"
+
+func TestPathToPrefix(t *testing.T) {
+	tests := []struct {
+		Path     string
+		Expected string
+	}{{"foo/bar/v1", "foo/bar/v1"},
+		{"foo/bar/v.1", "foo/bar/v%2e1"},
+		{"f.o.o/b.a.r/v1", "f.o.o/b.a.r/v1"},
+		{"f.o.o/b.a.r/v.1", "f.o.o/b.a.r/v%2e1"},
+		{"f.o.o/b.a.r/v..1", "f.o.o/b.a.r/v%2e%2e1"},
+		{"f.o.o/b.a.r/v..1.", "f.o.o/b.a.r/v%2e%2e1%2e"},
+		{"f.o.o/b.a.r/v%1", "f.o.o/b.a.r/v%251"},
+		{"runtime", "runtime"},
+		{"sync/atomic", "sync/atomic"},
+		{"golang.org/x/tools/godoc", "golang.org/x/tools/godoc"},
+		{"foo.bar/baz.quux", "foo.bar/baz%2equux"},
+		{"", ""},
+		{"%foo%bar", "%25foo%25bar"},
+		{"\x01\x00\x7F☺", "%01%00%7f%e2%98%ba"},
+	}
+	for _, tc := range tests {
+		if got := PathToPrefix(tc.Path); got != tc.Expected {
+			t.Errorf("expected PathToPrefix(%s) = %s, got %s", tc.Path, tc.Expected, got)
+		}
+	}
+}

src/cmd/link/internal/ld/data.go

@@ -1059,7 +1059,7 @@ func addstrdata1(ctxt *Link, arg string) {
 	if eq < 0 || dot < 0 {
 		Exitf("-X flag requires argument of the form importpath.name=value")
 	}
-	addstrdata(ctxt, pathtoprefix(arg[:dot])+arg[dot:eq], arg[eq+1:])
+	addstrdata(ctxt, objabi.PathToPrefix(arg[:dot])+arg[dot:eq], arg[eq+1:])
 }
 
 func addstrdata(ctxt *Link, name string, value string) {

src/cmd/link/internal/ld/lib.go

@@ -651,7 +651,7 @@ func (ctxt *Link) loadlib() {
 					// first containing package that the linker loads). canonicalize
 					// it here to the package with which it will be laid down
 					// in text.
-					s.File = pathtoprefix(lib.Pkg)
+					s.File = objabi.PathToPrefix(lib.Pkg)
 				}
 			}
 		}
@@ -752,7 +752,7 @@ func genhash(ctxt *Link, lib *Library) {
 }
 
 func objfile(ctxt *Link, lib *Library) {
-	pkg := pathtoprefix(lib.Pkg)
+	pkg := objabi.PathToPrefix(lib.Pkg)
 
 	if ctxt.Debugvlog > 1 {
 		ctxt.Logf("%5.2f ldobj: %s (%s)\n", Cputime(), lib.File, pkg)
@@ -1312,7 +1312,7 @@ func hostlinkArchArgs() []string {
 // compiled by a non-Go compiler) it returns the Hostobj pointer. If
 // it is a Go object, it returns nil.
 func ldobj(ctxt *Link, f *bio.Reader, lib *Library, length int64, pn string, file string, whence int) *Hostobj {
-	pkg := pathtoprefix(lib.Pkg)
+	pkg := objabi.PathToPrefix(lib.Pkg)
 
 	eof := f.Offset() + length
 	start := f.Offset()
@@ -1572,35 +1572,6 @@ func ldshlibsyms(ctxt *Link, shlib string) {
 	ctxt.Shlibs = append(ctxt.Shlibs, Shlib{Path: libpath, Hash: hash, Deps: deps, File: f, gcdataAddresses: gcdataAddresses})
 }
 
-// Copied from ../gc/subr.c:/^pathtoprefix; must stay in sync.
-/*
- * Convert raw string to the prefix that will be used in the symbol table.
- * Invalid bytes turn into %xx.	 Right now the only bytes that need
- * escaping are %, ., and ", but we escape all control characters too.
- *
- * If you edit this, edit ../gc/subr.c:/^pathtoprefix too.
- * If you edit this, edit ../../debug/goobj/read.go:/importPathToPrefix too.
- */
-func pathtoprefix(s string) string {
-	slash := strings.LastIndex(s, "/")
-	for i := 0; i < len(s); i++ {
-		c := s[i]
-		if c <= ' ' || i >= slash && c == '.' || c == '%' || c == '"' || c >= 0x7F {
-			var buf bytes.Buffer
-			for i := 0; i < len(s); i++ {
-				c := s[i]
-				if c <= ' ' || i >= slash && c == '.' || c == '%' || c == '"' || c >= 0x7F {
-					fmt.Fprintf(&buf, "%%%02x", c)
-					continue
-				}
-				buf.WriteByte(c)
-			}
-			return buf.String()
-		}
-	}
-	return s
-}
-
 func addsection(seg *Segment, name string, rwx int) *Section {
 	sect := new(Section)
 	sect.Rwx = uint8(rwx)

src/cmd/link/internal/ld/objfile.go

@@ -68,7 +68,7 @@ func LoadObjFile(ctxt *Link, f *bio.Reader, lib *Library, length int64, pn strin
 }
 
 func (r *objReader) loadObjFile() {
-	pkg := pathtoprefix(r.lib.Pkg)
+	pkg := objabi.PathToPrefix(r.lib.Pkg)
 
 	// Magic header
 	var buf [8]uint8
@@ -168,7 +168,7 @@ func (r *objReader) readSym() {
 	typ := r.readSymIndex()
 	data := r.readData()
 	nreloc := r.readInt()
-	pkg := pathtoprefix(r.lib.Pkg)
+	pkg := objabi.PathToPrefix(r.lib.Pkg)
 	isdup := false
 
 	var dup *Symbol
@@ -345,7 +345,7 @@ func (r *objReader) patchDWARFName(s *Symbol) {
 	if p == -1 {
 		return
 	}
-	pkgprefix := []byte(pathtoprefix(r.lib.Pkg) + ".")
+	pkgprefix := []byte(objabi.PathToPrefix(r.lib.Pkg) + ".")
 	patched := bytes.Replace(s.P[:e], emptyPkg, pkgprefix, -1)
 
 	s.P = append(patched, s.P[e:]...)
@@ -478,7 +478,7 @@ func (r *objReader) readData() []byte {
 
 // readSymName reads a symbol name, replacing all "". with pkg.
 func (r *objReader) readSymName() string {
-	pkg := pathtoprefix(r.lib.Pkg)
+	pkg := objabi.PathToPrefix(r.lib.Pkg)
 	n := r.readInt()
 	if n == 0 {
 		r.readInt64()