debug/gosym: Remove Makefile, rewrite test using go tool.

Update #2573.

R=r
CC=golang-dev
https://golang.org/cl/5656071

src/pkg/debug/gosym/Makefile

@@ -1,19 +0,0 @@
-# Copyright 2009 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.
-
-include ../../../Make.inc
-
-TARG=debug/gosym
-GOFILES=\
-	pclntab.go\
-	symtab.go\
-
-include ../../../Make.pkg
-
-test: make-pclinetest
-
-testshort: make-pclinetest
-
-make-pclinetest:
-	@if [ "`uname`-`uname -m`" = Linux-x86_64 -a $(GOARCH) = amd64 ]; then mkdir -p _test && $(AS) pclinetest.s && $(LD) -E main -o _test/pclinetest pclinetest.$O; fi

src/pkg/debug/gosym/pclinetest.asm

@@ -1,5 +1,3 @@
-// +build ignore
-
 TEXT linefrompc(SB),7,$0	// Each byte stores its line delta
 BYTE $2;
 BYTE $1;

src/pkg/debug/gosym/pclntab_test.go

@@ -7,14 +7,31 @@ package gosym
 import (
 	"debug/elf"
 	"os"
+	"os/exec"
 	"runtime"
+	"strings"
 	"testing"
 )
 
+var pclinetestBinary string
+
 func dotest() bool {
 	// For now, only works on ELF platforms.
-	// TODO: convert to work with new go tool
-	return false && runtime.GOOS == "linux" && runtime.GOARCH == "amd64"
+	if runtime.GOOS != "linux" || runtime.GOARCH != "amd64" {
+		return false
+	}
+	if pclinetestBinary != "" {
+		return true
+	}
+	// This command builds pclinetest from pclinetest.asm;
+	// the resulting binary looks like it was built from pclinetest.s,
+	// but we have renamed it to keep it away from the go tool.
+	pclinetestBinary = os.TempDir() + "/pclinetest"
+	cmd := exec.Command("sh", "-c", "go tool 6a pclinetest.asm && go tool 6l -E main -o "+pclinetestBinary+" pclinetest.6")
+	if err := cmd.Run(); err != nil {
+		panic(err)
+	}
+	return true
 }
 
 func getTable(t *testing.T) *Table {
@@ -149,7 +166,7 @@ func TestPCLine(t *testing.T) {
 		return
 	}
 
-	f, tab := crack("_test/pclinetest", t)
+	f, tab := crack(pclinetestBinary, t)
 	text := f.Section(".text")
 	textdat, err := text.Data()
 	if err != nil {
@@ -163,10 +180,13 @@ func TestPCLine(t *testing.T) {
 		file, line, fn := tab.PCToLine(pc)
 		off := pc - text.Addr // TODO(rsc): should not need off; bug in 8g
 		wantLine += int(textdat[off])
+		t.Logf("off is %d", off)
 		if fn == nil {
 			t.Errorf("failed to get line of PC %#x", pc)
-		} else if len(file) < 12 || file[len(file)-12:] != "pclinetest.s" || line != wantLine || fn != sym {
-			t.Errorf("expected %s:%d (%s) at PC %#x, got %s:%d (%s)", "pclinetest.s", wantLine, sym.Name, pc, file, line, fn.Name)
+		} else if !strings.HasSuffix(file, "pclinetest.s") {
+			t.Errorf("expected %s (%s) at PC %#x, got %s (%s)", "pclinetest.s", sym.Name, pc, file, fn.Name)
+		} else if line != wantLine || fn != sym {
+			t.Errorf("expected :%d (%s) at PC %#x, got :%d (%s)", wantLine, sym.Name, pc, line, fn.Name)
 		}
 	}