cmd/llgo-build: Add -test flag creating a test binary. For go-llvm#48.

This is able to create a binary for some packages, although I'm
having issues actually running them. Will comment in go-llvm#48 with more
details.

This PR depends on having merged the others first.

cmd/llgo-build/build.go

@@ -134,6 +134,20 @@ func getPackage(pkgpath string) (pkg *build.Package, err error) {
 			}
 			pkg.GoFiles[i] = path.Join(pkgdir, filename)
 		}
+		for i, filename := range pkg.TestGoFiles {
+			pkgdir := pkg.Dir
+			if overlayentries[filename] {
+				pkgdir = overlaypkg.Dir
+			}
+			pkg.TestGoFiles[i] = path.Join(pkgdir, filename)
+		}
+		for i, filename := range pkg.XTestGoFiles {
+			pkgdir := pkg.Dir
+			if overlayentries[filename] {
+				pkgdir = overlaypkg.Dir
+			}
+			pkg.XTestGoFiles[i] = path.Join(pkgdir, filename)
+		}
 		for i, filename := range pkg.CFiles {
 			pkgdir := pkg.Dir
 			if overlayentries[filename] {
@@ -191,7 +205,7 @@ func buildPackages(pkgpaths []string) error {
 func buildPackage(pkg *build.Package, output string) error {
 	args := []string{"-c", "-triple", triple}
 	dir, file := path.Split(pkg.ImportPath)
-	if pkg.IsCommand() {
+	if pkg.IsCommand() || test {
 		if output == "" {
 			output = file
 		}
@@ -211,6 +225,9 @@ func buildPackage(pkg *build.Package, output string) error {
 	tempfile := path.Join(workdir, file+".bc")
 	args = append(args, "-o", tempfile)
 	args = append(args, pkg.GoFiles...)
+	if test {
+		args = append(args, pkg.TestGoFiles...)
+	}
 	cmd := exec.Command("llgo", args...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
@@ -271,6 +288,10 @@ func buildPackage(pkg *build.Package, output string) error {
 		if err != nil {
 			return err
 		}
+	} else if test {
+		if err = linktest(pkg, tempfile); err != nil {
+			return err
+		}
 	}
 	return moveFile(tempfile, output)
 }

cmd/llgo-build/link.go

@@ -19,16 +19,16 @@ func linkdeps(pkg *build.Package, output string) error {
 	deps["runtime"] = true
 	deps["unsafe"] = true
 
-	var mkdeps func(pkg *build.Package) error
-	mkdeps = func(pkg *build.Package) error {
-		for _, path := range pkg.Imports {
+	var mkdeps func(pkg *build.Package, imports []string) error
+	mkdeps = func(pkg *build.Package, imports []string) error {
+		for _, path := range imports {
 			if !deps[path] {
 				deps[path] = true
 				pkg, err := build.Import(path, "", 0)
 				if err != nil {
 					return err
 				}
-				if err = mkdeps(pkg); err != nil {
+				if err = mkdeps(pkg, pkg.Imports); err != nil {
 					return err
 				}
 				depslist = append(depslist, path)
@@ -37,10 +37,18 @@ func linkdeps(pkg *build.Package, output string) error {
 		return nil
 	}
 
-	err := mkdeps(pkg)
+	err := mkdeps(pkg, pkg.Imports)
 	if err != nil {
 		return err
 	}
+	if test {
+		if err = mkdeps(pkg, pkg.TestImports); err != nil {
+			return err
+		}
+		if err = mkdeps(pkg, pkg.XTestImports); err != nil {
+			return err
+		}
+	}
 
 	for i := 0; i < len(depslist)/2; i++ {
 		j := len(depslist) - i - 1
@@ -50,6 +58,9 @@ func linkdeps(pkg *build.Package, output string) error {
 	llvmlink := filepath.Join(llvmbindir, "llvm-link")
 	args := []string{"-o", output, output}
 	for _, path := range depslist {
+		if path == pkg.ImportPath {
+			continue
+		}
 		bcfile := filepath.Join(pkgroot, path+".bc")
 		if buildDeps {
 			if _, err := os.Stat(bcfile); err != nil {

cmd/llgo-build/main.go

@@ -6,6 +6,7 @@ package main
 
 import (
 	"flag"
+	"fmt"
 	llgobuild "github.com/axw/llgo/build"
 	"go/build"
 	"io/ioutil"
@@ -28,6 +29,7 @@ var (
 	emitllvm      bool
 	buildctx      *build.Context
 	workdir       string
+	test          bool
 	buildDeps     bool = true
 )
 
@@ -37,6 +39,7 @@ func init() {
 	flag.StringVar(&output, "o", "", "Output file")
 	flag.BoolVar(&emitllvm, "emit-llvm", false, "Emit LLVM bitcode instead of a native binary")
 	flag.BoolVar(&printcommands, "x", false, "Print the commands")
+	flag.BoolVar(&test, "test", test, "When specified, the created output binary will be similar to what's output of \"go test -c\"")
 	flag.BoolVar(&buildDeps, "build-deps", buildDeps, "Whether to also build dependency packages or not")
 }
 
@@ -71,7 +74,16 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = buildPackages(flag.Args())
+	args := flag.Args()
+	if test {
+		if len(args) > 1 {
+			err = fmt.Errorf("Multiple files/packages can not be specified when building a test binary")
+		} else {
+			err = buildPackageTests(args[0])
+		}
+	} else {
+		err = buildPackages(flag.Args())
+	}
 	os.RemoveAll(workdir)
 	if err != nil {
 		log.Fatal(err)