loader: load packages using Go modules

This commit replaces the existing ad-hoc package loader with a package
loader that uses the x/tools/go/packages package to find all
to-be-loaded packages.

compiler/compiler.go

@@ -156,6 +156,7 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 			Compiler:    "gc", // must be one of the recognized compilers
 			BuildTags:   c.BuildTags(),
 		},
+		Tests: c.TestConfig.CompileTestBinary,
 		TypeChecker: types.Config{
 			Sizes: &stdSizes{
 				IntSize:  int64(c.targetData.TypeAllocSize(c.intType)),
@@ -169,33 +170,17 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 		ClangHeaders: c.ClangHeaders,
 	}
 
-	if strings.HasSuffix(pkgName, ".go") {
+	err = lprogram.Load(pkgName)
-		_, err = lprogram.ImportFile(pkgName)
-		if err != nil {
-			return c.mod, nil, []error{err}
-		}
-	} else {
-		_, err = lprogram.Import(pkgName, wd, token.Position{
-			Filename: "build command-line-arguments",
-		})
-		if err != nil {
-			return c.mod, nil, []error{err}
-		}
-	}
-
-	_, err = lprogram.Import("runtime", "", token.Position{
-		Filename: "build default import",
-	})
 	if err != nil {
 		return c.mod, nil, []error{err}
 	}
 
-	err = lprogram.Parse(c.TestConfig.CompileTestBinary)
+	err = lprogram.Parse()
 	if err != nil {
 		return c.mod, nil, []error{err}
 	}
 
-	c.ir = ir.NewProgram(lprogram, pkgName)
+	c.ir = ir.NewProgram(lprogram)
 
 	// Run a simple dead code elimination pass.
 	err = c.ir.SimpleDCE()
@@ -339,8 +324,11 @@ func Compile(pkgName string, machine llvm.TargetMachine, config *compileopts.Con
 	// Gather the list of (C) file paths that should be included in the build.
 	var extraFiles []string
 	for _, pkg := range c.ir.LoaderProgram.Sorted() {
-		for _, file := range pkg.CFiles {
+		for _, file := range pkg.OtherFiles {
-			extraFiles = append(extraFiles, filepath.Join(pkg.Package.Dir, file))
+			switch strings.ToLower(filepath.Ext(file)) {
+			case ".c":
+				extraFiles = append(extraFiles, file)
+			}
 		}
 	}
 

ir/ir.go

@@ -63,23 +63,13 @@ const (
 )
 
 // Create and initialize a new *Program from a *ssa.Program.
-func NewProgram(lprogram *loader.Program, mainPath string) *Program {
+func NewProgram(lprogram *loader.Program) *Program {
 	program := lprogram.LoadSSA()
 	program.Build()
 
 	// Find the main package, which is a bit difficult when running a .go file
 	// directly.
-	mainPkg := program.ImportedPackage(mainPath)
+	mainPkg := program.ImportedPackage(lprogram.MainPkg.PkgPath)
-	if mainPkg == nil {
-		for _, pkgInfo := range program.AllPackages() {
-			if pkgInfo.Pkg.Name() == "main" {
-				if mainPkg != nil {
-					panic("more than one main package found")
-				}
-				mainPkg = pkgInfo
-			}
-		}
-	}
 	if mainPkg == nil {
 		panic("could not find main package")
 	}
@@ -87,21 +77,10 @@ func NewProgram(lprogram *loader.Program, mainPath string) *Program {
 	// Make a list of packages in import order.
 	packageList := []*ssa.Package{}
 	packageSet := map[string]struct{}{}
-	worklist := []string{"runtime", mainPath}
+	worklist := []string{"runtime", lprogram.MainPkg.PkgPath}
 	for len(worklist) != 0 {
 		pkgPath := worklist[0]
-		var pkg *ssa.Package
+		pkg := program.ImportedPackage(pkgPath)
-		if pkgPath == mainPath {
-			pkg = mainPkg // necessary for compiling individual .go files
-		} else {
-			pkg = program.ImportedPackage(pkgPath)
-		}
-		if pkg == nil {
-			// Non-SSA package (e.g. cgo).
-			packageSet[pkgPath] = struct{}{}
-			worklist = worklist[1:]
-			continue
-		}
 		if _, ok := packageSet[pkgPath]; ok {
 			// Package already in the final package list.
 			worklist = worklist[1:]

loader/errors.go

@@ -1,10 +1,5 @@
 package loader
 
-import (
-	"go/token"
-	"strings"
-)
-
 // Errors contains a list of parser errors or a list of typechecker errors for
 // the given package.
 type Errors struct {
@@ -15,25 +10,3 @@ type Errors struct {
 func (e Errors) Error() string {
 	return "could not compile: " + e.Errs[0].Error()
 }
-
-// ImportCycleErrors is returned when encountering an import cycle. The list of
-// packages is a list from the root package to the leaf package that imports one
-// of the packages in the list.
-type ImportCycleError struct {
-	Packages        []string
-	ImportPositions []token.Position
-}
-
-func (e *ImportCycleError) Error() string {
-	var msg strings.Builder
-	msg.WriteString("import cycle:\n\t")
-	msg.WriteString(strings.Join(e.Packages, "\n\t"))
-	msg.WriteString("\n at ")
-	for i, pos := range e.ImportPositions {
-		if i > 0 {
-			msg.WriteString(", ")
-		}
-		msg.WriteString(pos.String())
-	}
-	return msg.String()
-}

loader/goroot.go

@@ -10,8 +10,10 @@ import (
 	"io/ioutil"
 	"math/rand"
 	"os"
+	"os/exec"
 	"path"
 	"path/filepath"
+	"runtime"
 	"strconv"
 
 	"github.com/tinygo-org/tinygo/compileopts"
@@ -58,8 +60,12 @@ func GetCachedGoroot(config *compileopts.Config) (string, error) {
 		return "", err
 	}
 
+	// Remove the temporary directory if it wasn't moved to the right place
+	// (for example, when there was an error).
+	defer os.RemoveAll(tmpgoroot)
+
 	for _, name := range []string{"bin", "lib", "pkg"} {
-		err = os.Symlink(filepath.Join(goroot, name), filepath.Join(tmpgoroot, name))
+		err = symlink(filepath.Join(goroot, name), filepath.Join(tmpgoroot, name))
 		if err != nil {
 			return "", err
 		}
@@ -72,8 +78,8 @@ func GetCachedGoroot(config *compileopts.Config) (string, error) {
 	if err != nil {
 		if os.IsExist(err) {
 			// Another invocation of TinyGo also seems to have created a GOROOT.
-			// Use that one instead and delete ours.
+			// Use that one instead. Our new GOROOT will be automatically
-			os.RemoveAll(tmpgoroot)
+			// deleted by the defer above.
 			return cachedgoroot, nil
 		}
 		return "", err
@@ -91,7 +97,7 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 			// root, so simply make a symlink.
 			newname := filepath.Join(tmpgoroot, "src", importPath)
 			oldname := filepath.Join(tinygoroot, "src", importPath)
-			return os.Symlink(oldname, newname)
+			return symlink(oldname, newname)
 		}
 
 		// Merge subdirectories. Start by making the directory to merge.
@@ -117,7 +123,7 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 				// A file, so symlink this.
 				newname := filepath.Join(tmpgoroot, "src", importPath, e.Name())
 				oldname := filepath.Join(tinygoroot, "src", importPath, e.Name())
-				err := os.Symlink(oldname, newname)
+				err := symlink(oldname, newname)
 				if err != nil {
 					return err
 				}
@@ -143,7 +149,7 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 			}
 			newname := filepath.Join(tmpgoroot, "src", importPath, e.Name())
 			oldname := filepath.Join(goroot, "src", importPath, e.Name())
-			err := os.Symlink(oldname, newname)
+			err := symlink(oldname, newname)
 			if err != nil {
 				return err
 			}
@@ -174,3 +180,46 @@ func pathsToOverride(needsSyscallPackage bool) map[string]bool {
 	}
 	return paths
 }
+
+// symlink creates a symlink or something similar. On Unix-like systems, it
+// always creates a symlink. On Windows, it tries to create a symlink and if
+// that fails, creates a hardlink or directory junction instead.
+//
+// Note that while Windows 10 does support symlinks and allows them to be
+// created using os.Symlink, it requires developer mode to be enabled.
+// Therefore provide a fallback for when symlinking is not possible.
+// Unfortunately this fallback only works when TinyGo is installed on the same
+// filesystem as the TinyGo cache and the Go installation (which is usually the
+// C drive).
+func symlink(oldname, newname string) error {
+	symlinkErr := os.Symlink(oldname, newname)
+	if runtime.GOOS == "windows" && symlinkErr != nil {
+		// Fallback for when developer mode is disabled.
+		// Note that we return the symlink error even if something else fails
+		// later on. This is because symlinks are the easiest to support
+		// (they're also used on Linux and MacOS) and enabling them is easy:
+		// just enable developer mode.
+		st, err := os.Stat(oldname)
+		if err != nil {
+			return symlinkErr
+		}
+		if st.IsDir() {
+			// Make a directory junction. There may be a way to do this
+			// programmatically, but it involves a lot of magic. Use the mklink
+			// command built into cmd instead (mklink is a builtin, not an
+			// external command).
+			err := exec.Command("cmd", "/k", "mklink", "/J", newname, oldname).Run()
+			if err != nil {
+				return symlinkErr
+			}
+		} else {
+			// Make a hard link.
+			err := os.Link(oldname, newname)
+			if err != nil {
+				return symlinkErr
+			}
+		}
+		return nil // success
+	}
+	return symlinkErr
+}

loader/loader.go

@@ -3,10 +3,10 @@ package loader
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"go/ast"
 	"go/build"
 	"go/parser"
-	"go/scanner"
 	"go/token"
 	"go/types"
 	"os"
@@ -16,13 +16,16 @@ import (
 	"text/template"
 
 	"github.com/tinygo-org/tinygo/cgo"
+	"github.com/tinygo-org/tinygo/goenv"
+	"golang.org/x/tools/go/packages"
 )
 
 // Program holds all packages and some metadata about the program as a whole.
 type Program struct {
-	mainPkg      string
 	Build        *build.Context
+	Tests        bool
 	Packages     map[string]*Package
+	MainPkg      *Package
 	sorted       []*Package
 	fset         *token.FileSet
 	TypeChecker  types.Config
@@ -35,85 +38,114 @@ type Program struct {
 // Package holds a loaded package, its imports, and its parsed files.
 type Package struct {
 	*Program
-	*build.Package
+	*packages.Package
-	Imports   map[string]*Package
+	Files []*ast.File
-	Importing bool
+	Pkg   *types.Package
-	Files     []*ast.File
-	Pkg       *types.Package
 	types.Info
 }
 
-// Import loads the given package relative to srcDir (for the vendor directory).
+// Load loads the given package with all dependencies (including the runtime
-// It only loads the current package without recursion.
+// package). Call .Parse() afterwards to parse all Go files (including CGo
-func (p *Program) Import(path, srcDir string, pos token.Position) (*Package, error) {
+// processing, if necessary).
+func (p *Program) Load(importPath string) error {
 	if p.Packages == nil {
 		p.Packages = make(map[string]*Package)
 	}
 
-	// Load this package.
+	err := p.loadPackage(importPath)
-	ctx := p.Build
-	buildPkg, err := ctx.Import(path, srcDir, build.ImportComment)
 	if err != nil {
-		return nil, scanner.Error{
+		return err
-			Pos: pos,
-			Msg: err.Error(), // TODO: define a new error type that will wrap the inner error
-		}
 	}
-	if existingPkg, ok := p.Packages[buildPkg.ImportPath]; ok {
+	p.MainPkg = p.sorted[len(p.sorted)-1]
-		// Already imported, or at least started the import.
+	if _, ok := p.Packages["runtime"]; !ok {
-		return existingPkg, nil
+		// The runtime package wasn't loaded. Although `go list -deps` seems to
+		// return the full dependency list, there is no way to get those
+		// packages from the go/packages package. Therefore load the runtime
+		// manually and add it to the list of to-be-compiled packages
+		// (duplicates are already filtered).
+		return p.loadPackage("runtime")
 	}
-	p.sorted = nil // invalidate the sorted order of packages
+	return nil
-	pkg := p.newPackage(buildPkg)
-	p.Packages[buildPkg.ImportPath] = pkg
-
-	if p.mainPkg == "" {
-		p.mainPkg = buildPkg.ImportPath
-	}
-
-	return pkg, nil
 }
 
-// ImportFile loads and parses the import statements in the given path and
+func (p *Program) loadPackage(importPath string) error {
-// creates a pseudo-package out of it.
+	cgoEnabled := "0"
-func (p *Program) ImportFile(path string) (*Package, error) {
+	if p.Build.CgoEnabled {
-	if p.Packages == nil {
+		cgoEnabled = "1"
-		p.Packages = make(map[string]*Package)
 	}
-	if _, ok := p.Packages[path]; ok {
+	pkgs, err := packages.Load(&packages.Config{
-		// unlikely
+		Mode:       packages.NeedName | packages.NeedFiles | packages.NeedImports | packages.NeedDeps,
-		return nil, errors.New("loader: cannot import file that is already imported as package: " + path)
+		Env:        append(os.Environ(), "GOROOT="+p.Build.GOROOT, "GOOS="+p.Build.GOOS, "GOARCH="+p.Build.GOARCH, "CGO_ENABLED="+cgoEnabled),
-	}
+		BuildFlags: []string{"-tags", strings.Join(p.Build.BuildTags, " ")},
-
+		Tests:      p.Tests,
-	file, err := p.parseFile(path, parser.ImportsOnly)
+	}, importPath)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	buildPkg := &build.Package{
+	var pkg *packages.Package
-		Dir:        filepath.Dir(path),
+	if p.Tests {
-		ImportPath: path,
+		// We need the second package. Quoting from the docs:
-		GoFiles:    []string{filepath.Base(path)},
+		// > For example, when using the go command, loading "fmt" with Tests=true
+		// > returns four packages, with IDs "fmt" (the standard package),
+		// > "fmt [fmt.test]" (the package as compiled for the test),
+		// > "fmt_test" (the test functions from source files in package fmt_test),
+		// > and "fmt.test" (the test binary).
+		pkg = pkgs[1]
+	} else {
+		if len(pkgs) != 1 {
+			return fmt.Errorf("expected exactly one package while importing %s, got %d", importPath, len(pkgs))
+		}
+		pkg = pkgs[0]
 	}
-	for _, importSpec := range file.Imports {
+	var importError *Errors
-		buildPkg.Imports = append(buildPkg.Imports, importSpec.Path.Value[1:len(importSpec.Path.Value)-1])
+	var addPackages func(pkg *packages.Package)
-	}
+	addPackages = func(pkg *packages.Package) {
-	p.sorted = nil // invalidate the sorted order of packages
+		if _, ok := p.Packages[pkg.PkgPath]; ok {
-	pkg := p.newPackage(buildPkg)
+			return
-	p.Packages[buildPkg.ImportPath] = pkg
+		}
+		pkg2 := p.newPackage(pkg)
+		p.Packages[pkg.PkgPath] = pkg2
+		if len(pkg.Errors) != 0 {
+			if importError != nil {
+				// There was another error reported already. Do not report
+				// errors from multiple packages at once.
+				return
+			}
+			importError = &Errors{
+				Pkg: pkg2,
+			}
+			for _, err := range pkg.Errors {
+				importError.Errs = append(importError.Errs, err)
+			}
+			return
+		}
 
-	if p.mainPkg == "" {
+		// Get the list of imports (sorted alphabetically).
-		p.mainPkg = buildPkg.ImportPath
+		names := make([]string, 0, len(pkg.Imports))
-	}
+		for name := range pkg.Imports {
+			names = append(names, name)
+		}
+		sort.Strings(names)
 
-	return pkg, nil
+		// Add all the imports.
+		for _, name := range names {
+			addPackages(pkg.Imports[name])
+		}
+
+		p.sorted = append(p.sorted, pkg2)
+	}
+	addPackages(pkg)
+	if importError != nil {
+		return importError
+	}
+	return nil
 }
 
 // newPackage instantiates a new *Package object with initialized members.
-func (p *Program) newPackage(pkg *build.Package) *Package {
+func (p *Program) newPackage(pkg *packages.Package) *Package {
 	return &Package{
 		Program: p,
 		Package: pkg,
-		Imports: make(map[string]*Package, len(pkg.Imports)),
 		Info: types.Info{
 			Types:      make(map[ast.Expr]types.TypeAndValue),
 			Defs:       make(map[*ast.Ident]types.Object),
@@ -128,87 +160,25 @@ func (p *Program) newPackage(pkg *build.Package) *Package {
 // Sorted returns a list of all packages, sorted in a way that no packages come
 // before the packages they depend upon.
 func (p *Program) Sorted() []*Package {
-	if p.sorted == nil {
-		p.sort()
-	}
 	return p.sorted
 }
 
-func (p *Program) sort() {
+// Parse parses all packages and typechecks them.
-	p.sorted = nil
-	packageList := make([]*Package, 0, len(p.Packages))
-	packageSet := make(map[string]struct{}, len(p.Packages))
-	worklist := make([]string, 0, len(p.Packages))
-	for path := range p.Packages {
-		worklist = append(worklist, path)
-	}
-	sort.Strings(worklist)
-	for len(worklist) != 0 {
-		pkgPath := worklist[0]
-		pkg := p.Packages[pkgPath]
-
-		if _, ok := packageSet[pkgPath]; ok {
-			// Package already in the final package list.
-			worklist = worklist[1:]
-			continue
-		}
-
-		unsatisfiedImports := make([]string, 0)
-		for _, pkg := range pkg.Imports {
-			if _, ok := packageSet[pkg.ImportPath]; ok {
-				continue
-			}
-			unsatisfiedImports = append(unsatisfiedImports, pkg.ImportPath)
-		}
-		sort.Strings(unsatisfiedImports)
-		if len(unsatisfiedImports) == 0 {
-			// All dependencies of this package are satisfied, so add this
-			// package to the list.
-			packageList = append(packageList, pkg)
-			packageSet[pkgPath] = struct{}{}
-			worklist = worklist[1:]
-		} else {
-			// Prepend all dependencies to the worklist and reconsider this
-			// package (by not removing it from the worklist). At that point, it
-			// must be possible to add it to packageList.
-			worklist = append(unsatisfiedImports, worklist...)
-		}
-	}
-
-	p.sorted = packageList
-}
-
-// Parse recursively imports all packages, parses them, and typechecks them.
 //
 // The returned error may be an Errors error, which contains a list of errors.
 //
 // Idempotent.
-func (p *Program) Parse(compileTestBinary bool) error {
+func (p *Program) Parse() error {
-	includeTests := compileTestBinary
-
-	// Load all imports
-	for _, pkg := range p.Sorted() {
-		err := pkg.importRecursively(includeTests)
-		if err != nil {
-			if err, ok := err.(*ImportCycleError); ok {
-				if pkg.ImportPath != err.Packages[0] {
-					err.Packages = append([]string{pkg.ImportPath}, err.Packages...)
-				}
-			}
-			return err
-		}
-	}
-
 	// Parse all packages.
 	for _, pkg := range p.Sorted() {
-		err := pkg.Parse(includeTests)
+		err := pkg.Parse()
 		if err != nil {
 			return err
 		}
 	}
 
-	if compileTestBinary {
+	if p.Tests {
-		err := p.SwapTestMain()
+		err := p.swapTestMain()
 		if err != nil {
 			return err
 		}
@@ -225,7 +195,7 @@ func (p *Program) Parse(compileTestBinary bool) error {
 	return nil
 }
 
-func (p *Program) SwapTestMain() error {
+func (p *Program) swapTestMain() error {
 	var tests []string
 
 	isTestFunc := func(f *ast.FuncDecl) bool {
@@ -235,8 +205,7 @@ func (p *Program) SwapTestMain() error {
 		}
 		return false
 	}
-	mainPkg := p.Packages[p.mainPkg]
+	for _, f := range p.MainPkg.Files {
-	for _, f := range mainPkg.Files {
 		for i, d := range f.Decls {
 			switch v := d.(type) {
 			case *ast.FuncDecl:
@@ -287,7 +256,7 @@ func main () {
 	if err != nil {
 		return err
 	}
-	path := filepath.Join(p.mainPkg, "$testmain.go")
+	path := filepath.Join(p.MainPkg.Dir, "$testmain.go")
 
 	if p.fset == nil {
 		p.fset = token.NewFileSet()
@@ -297,7 +266,7 @@ func main () {
 	if err != nil {
 		return err
 	}
-	mainPkg.Files = append(mainPkg.Files, newMain)
+	p.MainPkg.Files = append(p.MainPkg.Files, newMain)
 
 	return nil
 }
@@ -313,34 +282,41 @@ func (p *Program) parseFile(path string, mode parser.Mode) (*ast.File, error) {
 		return nil, err
 	}
 	defer rd.Close()
-	relpath := path
+	diagnosticPath := path
-	if filepath.IsAbs(path) {
+	if strings.HasPrefix(path, p.Build.GOROOT+string(filepath.Separator)) {
-		rp, err := filepath.Rel(p.Dir, path)
+		// If this file is part of the synthetic GOROOT, try to infer the
-		if err == nil {
+		// original path.
-			relpath = rp
+		relpath := path[len(p.Build.GOROOT)+1:]
+		tinygoPath := filepath.Join(p.TINYGOROOT, relpath)
+		if _, err := os.Stat(tinygoPath); err == nil {
+			diagnosticPath = tinygoPath
+		}
+		realgorootPath := filepath.Join(goenv.Get("GOROOT"), relpath)
+		if _, err := os.Stat(realgorootPath); err == nil {
+			diagnosticPath = realgorootPath
 		}
 	}
-	return parser.ParseFile(p.fset, relpath, rd, mode)
+	return parser.ParseFile(p.fset, diagnosticPath, rd, mode)
 }
 
 // Parse parses and typechecks this package.
 //
 // Idempotent.
-func (p *Package) Parse(includeTests bool) error {
+func (p *Package) Parse() error {
 	if len(p.Files) != 0 {
 		return nil
 	}
 
 	// Load the AST.
 	// TODO: do this in parallel.
-	if p.ImportPath == "unsafe" {
+	if p.PkgPath == "unsafe" {
 		// Special case for the unsafe package. Don't even bother loading
 		// the files.
 		p.Pkg = types.Unsafe
 		return nil
 	}
 
-	files, err := p.parseFiles(includeTests)
+	files, err := p.parseFiles()
 	if err != nil {
 		return err
 	}
@@ -367,7 +343,7 @@ func (p *Package) Check() error {
 	// Do typechecking of the package.
 	checker.Importer = p
 
-	typesPkg, err := checker.Check(p.ImportPath, p.fset, p.Files, &p.Info)
+	typesPkg, err := checker.Check(p.PkgPath, p.fset, p.Files, &p.Info)
 	if err != nil {
 		if err, ok := err.(Errors); ok {
 			return err
@@ -379,22 +355,14 @@ func (p *Package) Check() error {
 }
 
 // parseFiles parses the loaded list of files and returns this list.
-func (p *Package) parseFiles(includeTests bool) ([]*ast.File, error) {
+func (p *Package) parseFiles() ([]*ast.File, error) {
 	// TODO: do this concurrently.
 	var files []*ast.File
 	var fileErrs []error
 
-	var gofiles []string
+	var cgoFiles []*ast.File
-	if includeTests {
+	for _, file := range p.GoFiles {
-		gofiles = make([]string, 0, len(p.GoFiles)+len(p.TestGoFiles))
+		f, err := p.parseFile(file, parser.ParseComments)
-		gofiles = append(gofiles, p.GoFiles...)
-		gofiles = append(gofiles, p.TestGoFiles...)
-	} else {
-		gofiles = p.GoFiles
-	}
-
-	for _, file := range gofiles {
-		f, err := p.parseFile(filepath.Join(p.Package.Dir, file), parser.ParseComments)
 		if err != nil {
 			fileErrs = append(fileErrs, err)
 			continue
@@ -403,19 +371,15 @@ func (p *Package) parseFiles(includeTests bool) ([]*ast.File, error) {
 			fileErrs = append(fileErrs, err)
 			continue
 		}
+		for _, importSpec := range f.Imports {
+			if importSpec.Path.Value == `"C"` {
+				cgoFiles = append(cgoFiles, f)
+			}
+		}
 		files = append(files, f)
 	}
-	for _, file := range p.CgoFiles {
+	if len(cgoFiles) != 0 {
-		path := filepath.Join(p.Package.Dir, file)
+		cflags := append(p.CFlags, "-I"+filepath.Dir(p.GoFiles[0]))
-		f, err := p.parseFile(path, parser.ParseComments)
-		if err != nil {
-			fileErrs = append(fileErrs, err)
-			continue
-		}
-		files = append(files, f)
-	}
-	if len(p.CgoFiles) != 0 {
-		cflags := append(p.CFlags, "-I"+p.Package.Dir)
 		if p.ClangHeaders != "" {
 			cflags = append(cflags, "-Xclang", "-internal-isystem", "-Xclang", p.ClangHeaders)
 		}
@@ -439,58 +403,8 @@ func (p *Package) Import(to string) (*types.Package, error) {
 		return types.Unsafe, nil
 	}
 	if _, ok := p.Imports[to]; ok {
-		return p.Imports[to].Pkg, nil
+		return p.Packages[p.Imports[to].PkgPath].Pkg, nil
 	} else {
 		return nil, errors.New("package not imported: " + to)
 	}
 }
-
-// importRecursively calls Program.Import() on all imported packages, and calls
-// importRecursively() on the imported packages as well.
-//
-// Idempotent.
-func (p *Package) importRecursively(includeTests bool) error {
-	p.Importing = true
-
-	imports := p.Package.Imports
-	if includeTests {
-		imports = append(imports, p.Package.TestImports...)
-	}
-
-	for _, to := range imports {
-		if to == "C" {
-			// Do CGo processing in a later stage.
-			continue
-		}
-		if _, ok := p.Imports[to]; ok {
-			continue
-		}
-		// Find error location.
-		var pos token.Position
-		if len(p.Package.ImportPos[to]) > 0 {
-			pos = p.Package.ImportPos[to][0]
-		} else {
-			pos = token.Position{Filename: p.Package.ImportPath}
-		}
-		importedPkg, err := p.Program.Import(to, p.Package.Dir, pos)
-		if err != nil {
-			if err, ok := err.(*ImportCycleError); ok {
-				err.Packages = append([]string{p.ImportPath}, err.Packages...)
-			}
-			return err
-		}
-		if importedPkg.Importing {
-			return &ImportCycleError{[]string{p.ImportPath, importedPkg.ImportPath}, p.ImportPos[to]}
-		}
-		err = importedPkg.importRecursively(false)
-		if err != nil {
-			if err, ok := err.(*ImportCycleError); ok {
-				err.Packages = append([]string{p.ImportPath}, err.Packages...)
-			}
-			return err
-		}
-		p.Imports[to] = importedPkg
-	}
-	p.Importing = false
-	return nil
-}

main.go

@@ -714,7 +714,7 @@ func printCompilerError(logln func(...interface{}), err error) {
 			}
 		}
 	case loader.Errors:
-		logln("#", err.Pkg.ImportPath)
+		logln("#", err.Pkg.PkgPath)
 		for _, err := range err.Errs {
 			logln(err)
 		}