cmd/go: many improvements

* correct dependency calculations
* comment meaning of action fields
* new alias "std" like "all" but standard packages only
* add -o flag to 'go build'
* set up for parallel build (still serial)
* understand that import "C" depends on cgo, runtime/cgo

R=golang-dev, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/5502055

src/cmd/go/help.go

@@ -27,6 +27,9 @@ The special import path "all" expands to all package directories
 found in all the GOPATH trees.  For example, 'go list all' 
 lists all the packages on the local system.
 
+The special import path "std" is like all but expands to just the
+packages in the standard Go library.
+
 An import path can also name a package to be downloaded from
 a remote repository.  Run 'go help remote' for details.
 

src/cmd/go/list.go

@@ -33,6 +33,7 @@ being passed to the template is:
         ImportPath string // import path of package in dir
         Dir        string // directory containing package sources
         Version    string // version of installed package (TODO)
+        Stale      bool   // would 'go install' do anything for this package?
 
         // Source files
         GoFiles  []string // .go source files (excluding CgoFiles)

src/cmd/go/main.go

@@ -185,8 +185,10 @@ func help(args []string) {
 
 // importPaths returns the import paths to use for the given command line.
 func importPaths(args []string) []string {
-	if len(args) == 1 && args[0] == "all" {
-		return allPackages()
+	if len(args) == 1 {
+		if args[0] == "all" || args[0] == "std" {
+			return allPackages(args[0])
+		}
 	}
 	if len(args) == 0 {
 		return []string{"."}
@@ -236,10 +238,13 @@ func run(cmdline ...string) {
 
 // allPackages returns all the packages that can be found
 // under the $GOPATH directories and $GOROOT.
-func allPackages() []string {
+func allPackages(what string) []string {
 	have := map[string]bool{
 		"builtin": true, // ignore pseudo-package that exists only for documentation
 	}
+	if !build.DefaultContext.CgoEnabled {
+		have["runtime/cgo"] = true // ignore during walk
+	}
 	var pkgs []string
 
 	// Commands
@@ -270,6 +275,9 @@ func allPackages() []string {
 	})
 
 	for _, t := range build.Path {
+		if what == "std" && !t.Goroot {
+			continue
+		}
 		src := t.SrcDir() + string(filepath.Separator)
 		filepath.Walk(src, func(path string, fi os.FileInfo, err error) error {
 			if err != nil || !fi.IsDir() {
@@ -281,15 +289,21 @@ func allPackages() []string {
 				return filepath.SkipDir
 			}
 
+			name := filepath.ToSlash(path[len(src):])
+			if what == "std" && strings.Contains(name, ".") {
+				return filepath.SkipDir
+			}
+			if have[name] {
+				return nil
+			}
+
 			_, err = build.ScanDir(path)
 			if err != nil {
 				return nil
 			}
-			name := filepath.ToSlash(path[len(src):])
-			if !have[name] {
+
 			pkgs = append(pkgs, name)
 			have[name] = true
-			}
 
 			// Avoid go/build test data.
 			// TODO: Move it into a testdata directory.

src/cmd/go/run.go

@@ -33,7 +33,7 @@ func runRun(cmd *Command, args []string) {
 	var b builder
 	b.init(*runA, *runN, *runX)
 	p := goFilesPackage(args, "")
-	p.targ = "" // force rebuild - no up-to-date copy anywhere
+	p.target = "" // must build - not up to date
 	a1 := b.action(modeBuild, modeBuild, p)
 	a := &action{f: (*builder).runProgram, deps: []*action{a1}}
 	b.do(a)
@@ -42,6 +42,6 @@ func runRun(cmd *Command, args []string) {
 // runProgram is the action for running a binary that has already
 // been compiled.  We ignore exit status.
 func (b *builder) runProgram(a *action) error {
-	run(a.deps[0].pkgbin)
+	run(a.deps[0].target)
 	return nil
 }

src/cmd/go/test.go

@@ -228,10 +228,6 @@ func runTest(cmd *Command, args []string) {
 			errorf("%s: %s", p, err)
 			continue
 		}
-		if buildTest == nil {
-			// no test at all
-			continue
-		}
 		builds = append(builds, buildTest)
 		runs = append(runs, runTest)
 	}
@@ -254,7 +250,9 @@ func runTest(cmd *Command, args []string) {
 
 func (b *builder) test(p *Package) (buildAction, runAction *action, err error) {
 	if len(p.info.TestGoFiles)+len(p.info.XTestGoFiles) == 0 {
-		return &action{p: p}, &action{f: (*builder).notest, p: p}, nil
+		build := &action{p: p}
+		run := &action{f: (*builder).notest, p: p, deps: []*action{build}}
+		return build, run, nil
 	}
 
 	// Build Package structs describing:
@@ -292,6 +290,7 @@ func (b *builder) test(p *Package) (buildAction, runAction *action, err error) {
 	// $WORK/unicode/utf8/_test/unicode/utf8_test.a.
 	testDir := filepath.Join(b.work, filepath.FromSlash(p.ImportPath+"/_test"))
 	ptestObj := filepath.Join(testDir, filepath.FromSlash(p.ImportPath+".a"))
+	pxtestObj := filepath.Join(testDir, filepath.FromSlash(p.ImportPath+"_test.a"))
 
 	// Create the directory for the .a files.
 	ptestDir, _ := filepath.Split(ptestObj)
@@ -309,10 +308,15 @@ func (b *builder) test(p *Package) (buildAction, runAction *action, err error) {
 		ptest.GoFiles = nil
 		ptest.GoFiles = append(ptest.GoFiles, p.GoFiles...)
 		ptest.GoFiles = append(ptest.GoFiles, p.info.TestGoFiles...)
-		ptest.targ = "" // must rebuild
+		ptest.target = ""
 		ptest.Imports = append(append([]string{}, p.info.Imports...), p.info.TestImports...)
 		ptest.imports = append(append([]*Package{}, p.imports...), imports...)
 		ptest.pkgdir = testDir
+		a := b.action(modeBuild, modeBuild, ptest)
+		a.objdir = testDir + string(filepath.Separator)
+		a.objpkg = ptestObj
+		a.target = ptestObj
+		a.link = false
 	} else {
 		ptest = p
 	}
@@ -330,6 +334,11 @@ func (b *builder) test(p *Package) (buildAction, runAction *action, err error) {
 			imports:    imports,
 			pkgdir:     testDir,
 		}
+		pxtest.imports = append(pxtest.imports, ptest)
+		a := b.action(modeBuild, modeBuild, pxtest)
+		a.objdir = testDir + string(filepath.Separator)
+		a.objpkg = pxtestObj
+		a.target = pxtestObj
 	}
 
 	// Action for building test.out.
@@ -344,16 +353,19 @@ func (b *builder) test(p *Package) (buildAction, runAction *action, err error) {
 	if pxtest != nil {
 		pmain.imports = append(pmain.imports, pxtest)
 	}
-	pmainAction := b.action(modeBuild, modeBuild, pmain)
-	pmainAction.pkgbin = filepath.Join(testDir, "test.out")
+	a := b.action(modeBuild, modeBuild, pmain)
+	a.objdir = testDir + string(filepath.Separator)
+	a.objpkg = filepath.Join(testDir, "main.a")
+	a.target = filepath.Join(testDir, "test.out") + b.exe
+	pmainAction := a
 
 	if testC {
 		// -c flag: create action to copy binary to ./test.out.
-		pmain.targ = "test.out"
 		runAction = &action{
 			f:      (*builder).install,
 			deps:   []*action{pmainAction},
 			p:      pmain,
+			target: "test.out" + b.exe,
 		}
 	} else {
 		// run test
@@ -372,8 +384,11 @@ var pass = []byte("\nPASS\n")
 
 // runTest is the action for running a test binary.
 func (b *builder) runTest(a *action) error {
+	args := []string{a.deps[0].target}
+	args = append(args, testArgs...)
+
 	if b.nflag || b.xflag {
-		b.showcmd("%s", strings.Join(append([]string{a.deps[0].pkgbin}, testArgs...), " "))
+		b.showcmd("", "%s", strings.Join(args, " "))
 		if b.nflag {
 			return nil
 		}
@@ -387,7 +402,7 @@ func (b *builder) runTest(a *action) error {
 		return nil
 	}
 
-	cmd := exec.Command(a.deps[0].pkgbin, testArgs...)
+	cmd := exec.Command(args[0], args[1:]...)
 	cmd.Dir = a.p.Dir
 	out, err := cmd.CombinedOutput()
 	if err == nil && (bytes.Equal(out, pass[1:]) || bytes.HasSuffix(out, pass)) {