cmd/dist: cross-compiling fixes

This CL makes it possible to run make.bash with
GOOS and GOARCH set to something other than
the native host GOOS and GOARCH.

As part of the CL, the tool directory moves from bin/tool/
to pkg/tool/goos_goarch where goos and goarch are
the values for the host system (running the build), not
the target.  pkg/ is not technically appropriate, but C objects
are there now tool (pkg/obj/) so this puts all the generated
binaries in one place (rm -rf $GOROOT/pkg cleans everything).
Including goos_goarch in the name allows different systems
to share a single $GOROOT on a shared file system.

Fixes #2920.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5645093

src/all.bash

@@ -9,5 +9,5 @@ if [ ! -f make.bash ]; then
 	exit 1
 fi
 . ./make.bash --no-banner
-bash run.bash --no-rebuild
+bash run.bash --no-rebuild --banner
-../bin/tool/dist banner  # print build info
+$GOTOOLDIR/dist banner  # print build info

src/cmd/dist/a.h

@@ -72,7 +72,9 @@ extern char *goroot;
 extern char *goroot_final;
 extern char *goversion;
 extern char *workdir;
+extern char *tooldir;
 extern char *slash;
+extern bool rebuildall;
 
 int	find(char*, char**, int);
 void	init(void);

src/cmd/dist/build.c

@@ -13,15 +13,19 @@
 char *goarch;
 char *gobin;
 char *gohostarch;
+char *gohostchar;
 char *gohostos;
 char *goos;
 char *goroot = GOROOT_FINAL;
 char *goroot_final = GOROOT_FINAL;
 char *workdir;
+char	*tooldir;
 char *gochar;
 char *goversion;
 char *slash;	// / for unix, \ for windows
 
+bool	rebuildall = 0;
+
 static bool shouldbuild(char*, char*);
 static void copy(char*, char*);
 static char *findgoversion(void);
@@ -99,14 +103,18 @@ init(void)
 	if(b.len > 0)
 		gohostarch = btake(&b);
 
-	if(find(gohostarch, okgoarch, nelem(okgoarch)) < 0)
+	i = find(gohostarch, okgoarch, nelem(okgoarch));
+	if(i < 0)
 		fatal("unknown $GOHOSTARCH %s", gohostarch);
+	bprintf(&b, "%c", gochars[i]);
+	gohostchar = btake(&b);
 
 	xgetenv(&b, "GOARCH");
 	if(b.len == 0)
 		bwritestr(&b, gohostarch);
 	goarch = btake(&b);
-	if((i=find(goarch, okgoarch, nelem(okgoarch))) < 0)
+	i = find(goarch, okgoarch, nelem(okgoarch));
+	if(i < 0)
 		fatal("unknown $GOARCH %s", goarch);
 	bprintf(&b, "%c", gochars[i]);
 	gochar = btake(&b);
@@ -124,6 +132,9 @@ init(void)
 	workdir = xworkdir();
 	xatexit(rmworkdir);
 
+	bpathf(&b, "%s/pkg/tool/%s_%s", goroot, gohostos, gohostarch);
+	tooldir = btake(&b);
+
 	bfree(&b);
 }
 
@@ -256,6 +267,7 @@ static char *oldtool[] = {
 	"8a", "8c", "8g", "8l",
 	"6cov",
 	"6nm",
+	"6prof",
 	"cgo",
 	"ebnflint",
 	"goapi",
@@ -281,11 +293,8 @@ setup(void)
 
 	binit(&b);
 
-	// Create tool directory.
+	// Create bin directory.
 	p = bpathf(&b, "%s/bin", goroot);
-	if(!isdir(p))
-		xmkdir(p);
-	p = bpathf(&b, "%s/bin/tool", goroot);
 	if(!isdir(p))
 		xmkdir(p);
 
@@ -293,20 +302,41 @@ setup(void)
 	p = bpathf(&b, "%s/pkg", goroot);
 	if(!isdir(p))
 		xmkdir(p);
-	p = bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch);
+	p = bpathf(&b, "%s/pkg/%s_%s", goroot, gohostos, gohostarch);
+	if(rebuildall)
 		xremoveall(p);
 	xmkdir(p);
+	if(!streq(goos, gohostos) || !streq(goarch, gohostarch)) {
+		p = bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch);
+		if(rebuildall)
+			xremoveall(p);
+		xmkdir(p);
+	}
 	
 	// Create object directory.
 	// We keep it in pkg/ so that all the generated binaries
-	// are in one tree.
+	// are in one tree.  If pkg/obj/libgc.a exists, it is a dreg from
-	p = bpathf(&b, "%s/pkg/obj", goroot);
+	// before we used subdirectories of obj.  Delete all of obj
+	// to clean up.
+	bpathf(&b, "%s/pkg/obj/libgc.a", goroot);
+	if(isfile(bstr(&b)))
+		xremoveall(bpathf(&b, "%s/pkg/obj", goroot));
+	p = bpathf(&b, "%s/pkg/obj/%s_%s", goroot, gohostos, gohostarch);
+	if(rebuildall)
 		xremoveall(p);
-	xmkdir(p);
+	xmkdirall(p);
+
+	// Create tool directory.
+	// We keep it in pkg/, just like the object directory above.
+	xremoveall(tooldir);
+	xmkdirall(tooldir);
+
+	// Remove tool binaries from before the tool/gohostos_gohostarch
+	xremoveall(bpathf(&b, "%s/bin/tool", goroot));
 
 	// Remove old pre-tool binaries.
 	for(i=0; i<nelem(oldtool); i++)
-		xremove(bprintf(&b, "%s%s%s%s%s", goroot, slash, "bin", slash, oldtool[i]));
+		xremove(bpathf(&b, "%s/bin/%s", goroot, oldtool[i]));
 
 	// If $GOBIN is set and has a Go compiler, it must be cleaned.
 	for(i=0; gochars[i]; i++) {
@@ -390,37 +420,37 @@ static struct {
 		"../cc/pgen.c",
 		"../cc/pswt.c",
 		"../5l/enam.c",
-		"$GOROOT/pkg/obj/libcc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libcc.a",
 	}},
 	{"cmd/6c", {
 		"../cc/pgen.c",
 		"../cc/pswt.c",
 		"../6l/enam.c",
-		"$GOROOT/pkg/obj/libcc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libcc.a",
 	}},
 	{"cmd/8c", {
 		"../cc/pgen.c",
 		"../cc/pswt.c",
 		"../8l/enam.c",
-		"$GOROOT/pkg/obj/libcc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libcc.a",
 	}},
 	{"cmd/5g", {
 		"../gc/cplx.c",
 		"../gc/pgen.c",
 		"../5l/enam.c",
-		"$GOROOT/pkg/obj/libgc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/6g", {
 		"../gc/cplx.c",
 		"../gc/pgen.c",
 		"../6l/enam.c",
-		"$GOROOT/pkg/obj/libgc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/8g", {
 		"../gc/cplx.c",
 		"../gc/pgen.c",
 		"../8l/enam.c",
-		"$GOROOT/pkg/obj/libgc.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libgc.a",
 	}},
 	{"cmd/5l", {
 		"../ld/data.c",
@@ -442,9 +472,9 @@ static struct {
 		"enam.c",
 	}},
 	{"cmd/", {
-		"$GOROOT/pkg/obj/libmach.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libmach.a",
-		"$GOROOT/pkg/obj/libbio.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/libbio.a",
-		"$GOROOT/pkg/obj/lib9.a",
+		"$GOROOT/pkg/obj/$GOOS_$GOARCH/lib9.a",
 	}},
 	{"pkg/runtime", {
 		"zasm_$GOOS_$GOARCH.h",
@@ -490,8 +520,12 @@ install(char *dir)
 	Time ttarg, t;
 	int i, j, k, n, doclean;
 
-	if(vflag)
+	if(vflag) {
+		if(!streq(goos, gohostos) || !streq(goarch, gohostarch))
+			xprintf("%s (%s/%s)\n", dir, goos, goarch);
+		else
 			xprintf("%s\n", dir);
+	}
 
 	binit(&b);
 	binit(&b1);
@@ -521,7 +555,7 @@ install(char *dir)
 
 	islib = hasprefix(dir, "lib") || streq(dir, "cmd/cc") || streq(dir, "cmd/gc");
 	ispkg = hasprefix(dir, "pkg");
-	isgo = ispkg || streq(dir, "cmd/go");
+	isgo = ispkg || streq(dir, "cmd/go") || streq(dir, "cmd/cgo");
 
 	exe = "";
 	if(streq(gohostos, "windows"))
@@ -536,27 +570,30 @@ install(char *dir)
 		prefix = "";
 		if(!hasprefix(name, "lib"))
 			prefix = "lib";
-		vadd(&link, bpathf(&b, "%s/pkg/obj/%s%s.a", goroot, prefix, name));
+		vadd(&link, bpathf(&b, "%s/pkg/obj/%s_%s/%s%s.a", goroot, gohostos, gohostarch, prefix, name));
 	} else if(ispkg) {
 		// Go library (package).
-		vadd(&link, bpathf(&b, "%s/bin/tool/pack", goroot));
+		vadd(&link, bpathf(&b, "%s/pack", tooldir));
 		vadd(&link, "grc");
-		p = bprintf(&b, "%s/pkg/%s_%s/%s", goroot, goos, goarch, dir+4);
+		p = bprintf(&b, "%s/pkg/%s_%s/%s", goroot, gohostos, gohostarch, dir+4);
 		*xstrrchr(p, '/') = '\0';
 		xmkdirall(p);
-		vadd(&link, bpathf(&b, "%s/pkg/%s_%s/%s.a", goroot, goos, goarch, dir+4));
+		vadd(&link, bpathf(&b, "%s/pkg/%s_%s/%s.a", goroot, gohostos, gohostarch, dir+4));
-	} else if(streq(dir, "cmd/go")) {
+	} else if(streq(dir, "cmd/go") || streq(dir, "cmd/cgo")) {
 		// Go command.
-		vadd(&link, bpathf(&b, "%s/bin/tool/%sl", goroot, gochar));
+		vadd(&link, bpathf(&b, "%s/%sl", tooldir, gochar));
 		vadd(&link, "-o");
-		vadd(&link, bpathf(&b, "%s/bin/tool/go_bootstrap%s", goroot, exe));
+		elem = name;
+		if(streq(elem, "go"))
+			elem = "go_bootstrap";
+		vadd(&link, bpathf(&b, "%s/%s%s", tooldir, elem, exe));
 	} else {
 		// C command.
 		// Use gccargs, but ensure that link.p[2] is output file,
 		// as noted above.
 		vadd(&link, gccargs.p[0]);
 		vadd(&link, "-o");
-		vadd(&link, bpathf(&b, "%s/bin/tool/%s%s", goroot, name, exe));
+		vadd(&link, bpathf(&b, "%s/%s%s", tooldir, name, exe));
 		vcopy(&link, gccargs.p+1, gccargs.len-1);
 		if(streq(gohostarch, "amd64"))
 			vadd(&link, "-m64");
@@ -636,7 +673,7 @@ install(char *dir)
 	}
 
 	// Is the target up-to-date?
-	stale = 1;  // TODO: Decide when 0 is okay.
+	stale = rebuildall;
 	n = 0;
 	for(i=0; i<files.len; i++) {
 		p = files.p[i];
@@ -683,12 +720,6 @@ install(char *dir)
 			bpathf(&b1, "%s/signals_%s.h", bstr(&path), goos));
 	}
 
-	// For cmd/prof, copy pprof into the tool directory.
-	if(streq(dir, "cmd/prof")) {
-		copy(bpathf(&b, "%s/bin/tool/pprof", goroot),
-			bpathf(&b1, "%s/src/cmd/prof/pprof", goroot));
-	}
-
 	// Generate any missing files; regenerate existing ones.
 	for(i=0; i<files.len; i++) {
 		p = files.p[i];
@@ -738,6 +769,13 @@ install(char *dir)
 		vuniq(&files);
 	}
 	
+	if(!streq(goos, gohostos) || !streq(goarch, gohostarch)) {
+		// We've generated the right files; the go command can do the build.
+		if(vflag > 1)
+			xprintf("skip build for cross-compile %s\n", dir);
+		goto nobuild;
+	}
+
 	// Compile the files.
 	for(i=0; i<files.len; i++) {
 		if(!hassuffix(files.p[i], ".c") && !hassuffix(files.p[i], ".s"))
@@ -762,7 +800,7 @@ install(char *dir)
 			vadd(&compile, "-I");
 			vadd(&compile, bstr(&path));
 	
-			// runtime/goos.c gets the default constants hard-coded.
+			// lib9/goos.c gets the default constants hard-coded.
 			if(streq(name, "goos.c")) {
 				vadd(&compile, bprintf(&b, "-DGOOS=\"%s\"", goos));
 				vadd(&compile, bprintf(&b, "-DGOARCH=\"%s\"", goarch));
@@ -780,9 +818,9 @@ install(char *dir)
 		} else {
 			// Supporting files for a Go package.
 			if(hassuffix(files.p[i], ".s"))
-				vadd(&compile, bpathf(&b, "%s/bin/tool/%sa", goroot, gochar));
+				vadd(&compile, bpathf(&b, "%s/%sa", tooldir, gochar));
 			else {
-				vadd(&compile, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+				vadd(&compile, bpathf(&b, "%s/%sc", tooldir, gochar));
 				vadd(&compile, "-FVw");
 			}
 			vadd(&compile, "-I");
@@ -820,7 +858,7 @@ install(char *dir)
 		// The last loop was compiling individual files.
 		// Hand the Go files to the compiler en masse.
 		vreset(&compile);
-		vadd(&compile, bpathf(&b, "%s/bin/tool/%sg", goroot, gochar));
+		vadd(&compile, bpathf(&b, "%s/%sg", tooldir, gochar));
 
 		bpathf(&b, "%s/_go_.%s", workdir, gochar);
 		vadd(&compile, "-o");
@@ -853,6 +891,7 @@ install(char *dir)
 
 	runv(nil, nil, CheckExit, &link);
 
+nobuild:
 	// In package runtime, we install runtime.h and cgocall.h too,
 	// for use by cgo compilation.
 	if(streq(dir, "pkg/runtime")) {
@@ -921,6 +960,8 @@ shouldbuild(char *file, char *dir)
 	// so special case that file.
 	if(hassuffix(file, "cmd/go/doc.go") || hassuffix(file, "cmd\\go\\doc.go"))
 		return 0;
+	if(hassuffix(file, "cmd/cgo/doc.go") || hassuffix(file, "cmd\\cgo\\doc.go"))
+		return 0;
 
 	// Check file contents for // +build lines.
 	binit(&b);
@@ -940,7 +981,7 @@ shouldbuild(char *file, char *dir)
 			ret = 0;
 			goto out;
 		}
-		if(contains(p, "package main") && !streq(dir, "cmd/go")) {
+		if(contains(p, "package main") && !streq(dir, "cmd/go") && !streq(dir, "cmd/cgo")) {
 			ret = 0;
 			goto out;
 		}
@@ -1044,7 +1085,6 @@ static char *buildorder[] = {
 	"pkg/net/url",
 	"pkg/text/template/parse",
 	"pkg/text/template",
-
 	"cmd/go",
 };
 
@@ -1140,15 +1180,18 @@ clean(void)
 			xremove(bpathf(&b, "%s/%s", bstr(&path), cleantab[i]+4));
 	}
 
+	if(rebuildall) {
 		// Remove object tree.
-	xremoveall(bpathf(&b, "%s/pkg/obj", goroot));
+		xremoveall(bpathf(&b, "%s/pkg/obj/%s_%s", goroot, gohostos, gohostarch));
 	
 		// Remove installed packages and tools.
+		xremoveall(bpathf(&b, "%s/pkg/%s_%s", goroot, gohostos, gohostarch));
 		xremoveall(bpathf(&b, "%s/pkg/%s_%s", goroot, goos, goarch));
-	xremove(bpathf(&b, "%s/bin/tool", goroot));
+		xremoveall(tooldir);
 
 		// Remove cached version info.
 		xremove(bpathf(&b, "%s/VERSION.cache", goroot));
+	}
 
 	bfree(&b);
 	bfree(&path);
@@ -1212,7 +1255,11 @@ cmdenv(int argc, char **argv)
 	xprintf(format, "GOBIN", gobin);
 	xprintf(format, "GOARCH", goarch);
 	xprintf(format, "GOOS", goos);
+	xprintf(format, "GOHOSTARCH", gohostarch);
+	xprintf(format, "GOHOSTOS", gohostos);
+	xprintf(format, "GOTOOLDIR", tooldir);
 	xprintf(format, "GOCHAR", gochar);
+
 	if(pflag) {
 		sep = ":";
 		if(streq(gohostos, "windows"))
@@ -1233,8 +1280,14 @@ cmdbootstrap(int argc, char **argv)
 {
 	int i;
 	Buf b;
+	char *oldgoos, *oldgoarch, *oldgochar;
+
+	binit(&b);
 
 	ARGBEGIN{
+	case 'a':
+		rebuildall = 1;
+		break;
 	case 'v':
 		vflag++;
 		break;
@@ -1249,9 +1302,32 @@ cmdbootstrap(int argc, char **argv)
 	goversion = findgoversion();
 	setup();
 	
-	binit(&b);
+	// For the main bootstrap, building for host os/arch.
-	for(i=0; i<nelem(buildorder); i++)
+	oldgoos = goos;
-		install(bprintf(&b, buildorder[i], gochar));
+	oldgoarch = goarch;
+	oldgochar = gochar;
+	goos = gohostos;
+	goarch = gohostarch;
+	gochar = gohostchar;
+	xsetenv("GOARCH", goarch);
+	xsetenv("GOOS", goos);
+	
+	for(i=0; i<nelem(buildorder); i++) {
+		install(bprintf(&b, buildorder[i], gohostchar));
+		if(!streq(oldgochar, gohostchar) && xstrstr(buildorder[i], "%s"))
+			install(bprintf(&b, buildorder[i], oldgochar));
+	}
+
+	goos = oldgoos;
+	goarch = oldgoarch;
+	gochar = oldgochar;
+	xsetenv("GOARCH", goarch);
+	xsetenv("GOOS", goos);
+
+	// Build pkg/runtime for actual goos/goarch too.
+	if(!streq(goos, gohostos) || !streq(goarch, gohostarch))
+		install("pkg/runtime");
+
 	bfree(&b);
 }
 

src/cmd/dist/buildruntime.c

@@ -191,7 +191,7 @@ ok:
 	// Run 6c -DGOOS_goos -DGOARCH_goarch -Iworkdir -a proc.c
 	// to get acid [sic] output.
 	vreset(&argv);
-	vadd(&argv, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+	vadd(&argv, bpathf(&b, "%s/%sc", tooldir, gochar));
 	vadd(&argv, bprintf(&b, "-DGOOS_%s", goos));
 	vadd(&argv, bprintf(&b, "-DGOARCH_%s", goarch));
 	vadd(&argv, bprintf(&b, "-I%s", workdir));
@@ -287,7 +287,7 @@ mkzruntimedefs(char *dir, char *file)
 	
 	// Run 6c -DGOOS_goos -DGOARCH_goarch -Iworkdir -q
 	// on each of the runtimedefs C files.
-	vadd(&argv, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+	vadd(&argv, bpathf(&b, "%s/%sc", tooldir, gochar));
 	vadd(&argv, bprintf(&b, "-DGOOS_%s", goos));
 	vadd(&argv, bprintf(&b, "-DGOARCH_%s", goarch));
 	vadd(&argv, bprintf(&b, "-I%s", workdir));

src/cmd/dist/goc2c.c

@@ -709,15 +709,23 @@ goc2c(char *goc, char *c)
 
 	// TODO: set gcc=1 when using gcc
 
-	if(!gcc && streq(goarch, "amd64")) {
+	if(!gcc) {
+		if(streq(goarch, "amd64")) {
 			type_table[Uintptr].size = 8;
 			type_table[String].size = 16;
 			type_table[Slice].size = 8+4+4;
 			type_table[Eface].size = 8+8;
 			structround = 8;
+		} else {
+			type_table[Uintptr].size = 4;
+			type_table[String].size = 8;
+			type_table[Slice].size = 16;
+			type_table[Eface].size = 4+4;
+			structround = 4;
+		}
 	}
 
-	bprintf(&out, "// auto generated by go tool dist\n\n");
+	bprintf(&out, "// auto generated by go tool dist\n// goos=%s goarch=%s\n\n", goos, goarch);
 	input = bstr(&in);
 	output = &out;
 

src/cmd/dist/unix.c

@@ -145,6 +145,7 @@ static struct {
 	int pid;
 	int mode;
 	char *cmd;
+	Buf *b;
 } bg[MAXBG];
 static int nbg;
 static int maxnbg = nelem(bg);
@@ -219,6 +220,7 @@ genrun(Buf *b, char *dir, int mode, Vec *argv, int wait)
 	bg[nbg].pid = pid;
 	bg[nbg].mode = mode;
 	bg[nbg].cmd = btake(&cmd);
+	bg[nbg].b = b;
 	nbg++;
 	
 	if(wait)
@@ -233,6 +235,7 @@ bgwait1(void)
 {
 	int i, pid, status, mode;
 	char *cmd;
+	Buf *b;
 
 	errno = 0;
 	while((pid = wait(&status)) < 0) {
@@ -248,9 +251,13 @@ ok:
 	cmd = bg[i].cmd;
 	mode = bg[i].mode;
 	bg[i].pid = 0;
+	b = bg[i].b;
+	bg[i].b = nil;
 	bg[i] = bg[--nbg];
 	
 	if(mode == CheckExit && (!WIFEXITED(status) || WEXITSTATUS(status) != 0)) {
+		if(b != nil)
+			xprintf("%s\n", bstr(b));
 		fatal("FAILED: %s", cmd);
 	}
 	xfree(cmd);

src/cmd/go/build.go

@@ -347,7 +347,13 @@ func (b *builder) action(mode buildMode, depMode buildMode, p *Package) *action
 		a.deps = append(a.deps, b.action(depMode, depMode, p1))
 	}
 
-	if len(p.CgoFiles) > 0 {
+	// If we are not doing a cross-build, then record the binary we'll
+	// generate for cgo as a dependency of the build of any package
+	// using cgo, to make sure we do not overwrite the binary while
+	// a package is using it.  If this is a cross-build, then the cgo we
+	// are writing is not the cgo we need to use.
+	if b.goos == runtime.GOOS && b.goarch == runtime.GOARCH {
+		if len(p.CgoFiles) > 0 || p.Standard && p.ImportPath == "runtime/cgo" {
 			var stk importStack
 			p1 := loadPackage("cmd/cgo", &stk)
 			if p1.Error != nil {
@@ -356,6 +362,7 @@ func (b *builder) action(mode buildMode, depMode buildMode, p *Package) *action
 			a.cgo = b.action(depMode, depMode, p1)
 			a.deps = append(a.deps, a.cgo)
 		}
+	}
 
 	if p.Standard {
 		switch p.ImportPath {
@@ -567,7 +574,11 @@ func (b *builder) build(a *action) error {
 			sfiles = nil
 		}
 
-		outGo, outObj, err := b.cgo(a.p, a.cgo.target, obj, gccfiles)
+		cgoExe := tool("cgo")
+		if a.cgo != nil {
+			cgoExe = a.cgo.target
+		}
+		outGo, outObj, err := b.cgo(a.p, cgoExe, obj, gccfiles)
 		if err != nil {
 			return err
 		}

src/cmd/go/pkg.go

@@ -295,13 +295,14 @@ func scanPackage(ctxt *build.Context, t *build.Tree, arg, importPath, dir string
 
 	if info.Package == "main" {
 		_, elem := filepath.Split(importPath)
+		full := ctxt.GOOS + "_" + ctxt.GOARCH + "/" + elem
+		if t.Goroot && isGoTool[p.ImportPath] {
+			p.target = filepath.Join(t.Path, "pkg/tool", full)
+		} else {
 			if ctxt.GOOS != toolGOOS || ctxt.GOARCH != toolGOARCH {
 				// Install cross-compiled binaries to subdirectories of bin.
-			elem = ctxt.GOOS + "_" + ctxt.GOARCH + "/" + elem
+				elem = full
 			}
-		if t.Goroot && isGoTool[p.ImportPath] {
-			p.target = filepath.Join(t.Path, "bin/tool", elem)
-		} else {
 			p.target = filepath.Join(t.BinDir(), elem)
 		}
 		if ctxt.GOOS == "windows" {

src/cmd/go/tool.go

@@ -31,7 +31,7 @@ var (
 	toolGOOS      = runtime.GOOS
 	toolGOARCH    = runtime.GOARCH
 	toolIsWindows = toolGOOS == "windows"
-	toolDir       = filepath.Join(build.Path[0].Path, "bin", "tool")
+	toolDir       = build.ToolDir
 )
 
 const toolWindowsExtension = ".exe"
@@ -97,6 +97,7 @@ func listTools() {
 		setExitStatus(2)
 		return
 	}
+
 	sort.Strings(names)
 	for _, name := range names {
 		// Unify presentation by going to lower case.

src/make.bash

@@ -61,24 +61,36 @@ mkdir -p ../bin/tool
 export GOROOT="$(cd .. && pwd)"
 GOROOT_FINAL="${GOROOT_FINAL:-$GOROOT}"
 DEFGOROOT='-DGOROOT_FINAL="'"$GOROOT_FINAL"'"'
-gcc -O2 -Wall -Werror -o ../bin/tool/dist -Icmd/dist "$DEFGOROOT" cmd/dist/*.c
+gcc -O2 -Wall -Werror -ggdb -o cmd/dist/dist -Icmd/dist "$DEFGOROOT" cmd/dist/*.c
+eval $(./cmd/dist/dist env)
 echo
 
 if [ "$1" = "--dist-tool" ]; then
 	# Stop after building dist tool.
+	mv cmd/dist/dist $GOTOOLDIR/dist
 	exit 0
 fi
 
-echo '# Building compilers and Go bootstrap tool.'
+echo "# Building compilers and Go bootstrap tool for host, $GOHOSTOS/$GOHOSTARCH."
-../bin/tool/dist bootstrap -v # builds go_bootstrap
+./cmd/dist/dist bootstrap -a -v # builds go_bootstrap
+# Delay move of dist tool to now, because bootstrap cleared tool directory.
+mv cmd/dist/dist $GOTOOLDIR/dist
+$GOTOOLDIR/go_bootstrap clean -i std
 echo
 
-echo '# Building packages and commands.'
+if [ "$GOHOSTARCH" != "$GOARCH" -o "$GOHOSTOS" != "$GOOS" ]; then
-../bin/tool/go_bootstrap clean std
+	echo "# Building packages and commands for host, $GOHOSTOS/$GOHOSTARCH."
-../bin/tool/go_bootstrap install -a -v std
+	GOOS=$GOHOSTOS GOARCH=$GOHOSTARCH \
-rm -f ../bin/tool/go_bootstrap
+		$GOTOOLDIR/go_bootstrap install -v std
 	echo
+fi
+
+echo "# Building packages and commands for $GOOS/$GOARCH."
+$GOTOOLDIR/go_bootstrap install -v std
+echo
+
+rm -f $GOTOOLDIR/go_bootstrap
 
 if [ "$1" != "--no-banner" ]; then
-	../bin/tool/dist banner
+	$GOTOOLDIR/dist banner
 fi

src/make.bat

@@ -25,26 +25,48 @@ echo # Building C bootstrap tool.
 echo cmd/dist
 if not exist ..\bin\tool mkdir ..\bin\tool
 :: Windows has no glob expansion, so spell out cmd/dist/*.c.
-gcc -O2 -Wall -Werror -o ../bin/tool/dist.exe -Icmd/dist %DEFGOROOT% cmd/dist/buf.c cmd/dist/build.c cmd/dist/buildgc.c cmd/dist/buildruntime.c cmd/dist/goc2c.c cmd/dist/main.c cmd/dist/windows.c
+gcc -O2 -Wall -Werror -o cmd/dist/dist.exe -Icmd/dist %DEFGOROOT% cmd/dist/buf.c cmd/dist/build.c cmd/dist/buildgc.c cmd/dist/buildruntime.c cmd/dist/goc2c.c cmd/dist/main.c cmd/dist/windows.c
 if errorlevel 1 goto fail
+.\cmd\dist\dist env -wp >env.bat
+if errorlevel 1 goto fail
+call env.bat
+del env.bat
 :: Echo with no arguments prints whether echo is turned on, so echo dot.
 echo .
 
 echo # Building compilers and Go bootstrap tool.
-..\bin\tool\dist bootstrap -v
+.\cmd\dist\dist bootstrap -a -v
+if errorlevel 1 goto fail
+:: Delay move of dist tool to now, because bootstrap cleared tool directory.
+move .\cmd\dist\dist.exe %GOTOOLDIR%\dist.exe
+%GOTOOLDIR%\go_bootstrap clean -i std
+echo .
+
+if not %GOHOSTARCH% == %GOARCH% goto localbuild
+if not %GOHOSTOS% == %GOOS% goto localbuild
+goto mainbuild
+
+:localbuild
+echo # Building tools for local system. %GOHOSTOS%/%GOHOSTARCH%
+set oldGOOS=%GOOS%
+set oldGOARCH=%GOARCH%
+set GOOS=%GOHOSTOS%
+set GOARCH=%GOHOSTARCH%
+%GOTOOLDIR%\go_bootstrap install -v std
+set GOOS=%oldGOOS%
+set GOARCH=%oldGOARCH%
 if errorlevel 1 goto fail
 echo .
 
+:mainbuild
 echo # Building packages and commands.
-..\bin\tool\go_bootstrap clean std
+%GOTOOLDIR%\go_bootstrap install -a -v std
 if errorlevel 1 goto fail
-..\bin\tool\go_bootstrap install -a -v std
+del %GOTOOLDIR%\go_bootstrap.exe
-if errorlevel 1 goto fail
-del ..\bin\tool\go_bootstrap.exe
 echo .
 
 if "x%1"=="x--no-banner" goto nobanner
-..\bin\tool\dist banner
+%GOTOOLDIR%\dist banner
 :nobanner
 
 goto end

src/pkg/exp/types/gcimporter_test.go

@@ -6,7 +6,9 @@ package types
 
 import (
 	"go/ast"
+	"go/build"
 	"io/ioutil"
+	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
@@ -31,7 +33,7 @@ func init() {
 		gcPath = gcName
 		return
 	}
-	gcPath = filepath.Join(runtime.GOROOT(), "/bin/tool/", gcName)
+	gcPath = filepath.Join(build.ToolDir, gcName)
 }
 
 func compile(t *testing.T, dirname, filename string) {
@@ -90,6 +92,13 @@ func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
 }
 
 func TestGcImport(t *testing.T) {
+	// On cross-compile builds, the path will not exist.
+	// Need to use GOHOSTOS, which is not available.
+	if _, err := os.Stat(gcPath); err != nil {
+		t.Logf("skipping test: %v", err)
+		return
+	}
+
 	compile(t, "testdata", "exports.go")
 
 	nimports := 0

src/pkg/go/build/path.go

@@ -12,6 +12,9 @@ import (
 	"runtime"
 )
 
+// ToolDir is the directory containing build tools.
+var ToolDir = filepath.Join(runtime.GOROOT(), "pkg/tool/"+runtime.GOOS+"_"+runtime.GOARCH)
+
 // Path is a validated list of Trees derived from $GOROOT and $GOPATH at init.
 var Path []*Tree
 

src/run.bash

@@ -5,7 +5,7 @@
 
 set -e
 
-eval $(../bin/tool/dist env -p)
+eval $(go tool dist env)
 
 unset CDPATH	# in case user has it set
 

test/fixedbugs/bug302.go

@@ -1,4 +1,4 @@
-// $G $D/bug302.dir/p.go && "$GOROOT"/bin/tool/pack grc pp.a p.$A && $G $D/bug302.dir/main.go
+// $G $D/bug302.dir/p.go && pack grc pp.a p.$A && $G $D/bug302.dir/main.go
 
 // Copyright 2010 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style

test/run

@@ -3,7 +3,7 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-eval $(../bin/tool/dist env)
+eval $(go tool dist env)
 export GOARCH GOOS GOROOT
 export E=
 
@@ -34,7 +34,7 @@ failed=0
 PATH=${GOBIN:-$GOROOT/bin}:`pwd`:/bin:/usr/bin:/usr/local/bin
 
 # TODO: We add the tool directory to the PATH to avoid thinking about a better way.
-PATH="$GOROOT/bin/tool":$PATH
+PATH="$GOTOOLDIR:$PATH"
 
 RUNFILE="/tmp/gorun-$$-$USER"
 TMP1FILE="/tmp/gotest1-$$-$USER"