libgo: Add sources for go, cgo, and gofmt commands.

The new commands are not yet built.  That will be done
separately.

Also include a few changes to go/build to support them.

From-SVN: r219272

libgo/Makefile.am

@@ -26,6 +26,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibgo_toolexecdir)
 toolexeclibdir = $(glibgo_toolexeclibdir)
 toolexeclibgodir = $(nover_glibgo_toolexeclibdir)/go/$(gcc_version)/$(target_alias)
+libexecsubdir = $(libexecdir)/gcc/$(target_alias)/$(gcc_version)
 
 LIBFFI = @LIBFFI@
 LIBFFIINCS = @LIBFFIINCS@
@@ -1007,6 +1008,7 @@ s-version: Makefile
 	echo 'const theVersion = "'`$(GOC) --version | sed 1q`'"' >> version.go.tmp
 	echo 'const theGoarch = "'$(GOARCH)'"' >> version.go.tmp
 	echo 'const theGoos = "'$(GOOS)'"' >> version.go.tmp
+	echo 'const theGccgoToolDir = "$(libexecsubdir)"' >> version.go.tmp
 	$(SHELL) $(srcdir)/mvifdiff.sh version.go.tmp version.go
 	$(STAMP) $@
 

libgo/Makefile.in

@@ -454,6 +454,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibgo_toolexecdir)
 toolexeclibdir = $(glibgo_toolexeclibdir)
 toolexeclibgodir = $(nover_glibgo_toolexeclibdir)/go/$(gcc_version)/$(target_alias)
+libexecsubdir = $(libexecdir)/gcc/$(target_alias)/$(gcc_version)
 WARN_CFLAGS = $(WARN_FLAGS) $(WERROR)
 
 # -I/-D flags to pass when compiling.
@@ -4392,6 +4393,7 @@ s-version: Makefile
 	echo 'const theVersion = "'`$(GOC) --version | sed 1q`'"' >> version.go.tmp
 	echo 'const theGoarch = "'$(GOARCH)'"' >> version.go.tmp
 	echo 'const theGoos = "'$(GOOS)'"' >> version.go.tmp
+	echo 'const theGccgoToolDir = "$(libexecsubdir)"' >> version.go.tmp
 	$(SHELL) $(srcdir)/mvifdiff.sh version.go.tmp version.go
 	$(STAMP) $@
 

libgo/go/cmd/cgo/ast.go

@@ -0,0 +1,460 @@
+// 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.
+
+// Parse input AST and prepare Prog structure.
+
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/scanner"
+	"go/token"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func parse(name string, flags parser.Mode) *ast.File {
+	ast1, err := parser.ParseFile(fset, name, nil, flags)
+	if err != nil {
+		if list, ok := err.(scanner.ErrorList); ok {
+			// If err is a scanner.ErrorList, its String will print just
+			// the first error and then (+n more errors).
+			// Instead, turn it into a new Error that will return
+			// details for all the errors.
+			for _, e := range list {
+				fmt.Fprintln(os.Stderr, e)
+			}
+			os.Exit(2)
+		}
+		fatalf("parsing %s: %s", name, err)
+	}
+	return ast1
+}
+
+func sourceLine(n ast.Node) int {
+	return fset.Position(n.Pos()).Line
+}
+
+// ReadGo populates f with information learned from reading the
+// Go source file with the given file name.  It gathers the C preamble
+// attached to the import "C" comment, a list of references to C.xxx,
+// a list of exported functions, and the actual AST, to be rewritten and
+// printed.
+func (f *File) ReadGo(name string) {
+	// Create absolute path for file, so that it will be used in error
+	// messages and recorded in debug line number information.
+	// This matches the rest of the toolchain. See golang.org/issue/5122.
+	if aname, err := filepath.Abs(name); err == nil {
+		name = aname
+	}
+
+	// Two different parses: once with comments, once without.
+	// The printer is not good enough at printing comments in the
+	// right place when we start editing the AST behind its back,
+	// so we use ast1 to look for the doc comments on import "C"
+	// and on exported functions, and we use ast2 for translating
+	// and reprinting.
+	ast1 := parse(name, parser.ParseComments)
+	ast2 := parse(name, 0)
+
+	f.Package = ast1.Name.Name
+	f.Name = make(map[string]*Name)
+
+	// In ast1, find the import "C" line and get any extra C preamble.
+	sawC := false
+	for _, decl := range ast1.Decls {
+		d, ok := decl.(*ast.GenDecl)
+		if !ok {
+			continue
+		}
+		for _, spec := range d.Specs {
+			s, ok := spec.(*ast.ImportSpec)
+			if !ok || string(s.Path.Value) != `"C"` {
+				continue
+			}
+			sawC = true
+			if s.Name != nil {
+				error_(s.Path.Pos(), `cannot rename import "C"`)
+			}
+			cg := s.Doc
+			if cg == nil && len(d.Specs) == 1 {
+				cg = d.Doc
+			}
+			if cg != nil {
+				f.Preamble += fmt.Sprintf("#line %d %q\n", sourceLine(cg), name)
+				f.Preamble += commentText(cg) + "\n"
+			}
+		}
+	}
+	if !sawC {
+		error_(token.NoPos, `cannot find import "C"`)
+	}
+
+	// In ast2, strip the import "C" line.
+	w := 0
+	for _, decl := range ast2.Decls {
+		d, ok := decl.(*ast.GenDecl)
+		if !ok {
+			ast2.Decls[w] = decl
+			w++
+			continue
+		}
+		ws := 0
+		for _, spec := range d.Specs {
+			s, ok := spec.(*ast.ImportSpec)
+			if !ok || string(s.Path.Value) != `"C"` {
+				d.Specs[ws] = spec
+				ws++
+			}
+		}
+		if ws == 0 {
+			continue
+		}
+		d.Specs = d.Specs[0:ws]
+		ast2.Decls[w] = d
+		w++
+	}
+	ast2.Decls = ast2.Decls[0:w]
+
+	// Accumulate pointers to uses of C.x.
+	if f.Ref == nil {
+		f.Ref = make([]*Ref, 0, 8)
+	}
+	f.walk(ast2, "prog", (*File).saveRef)
+
+	// Accumulate exported functions.
+	// The comments are only on ast1 but we need to
+	// save the function bodies from ast2.
+	// The first walk fills in ExpFunc, and the
+	// second walk changes the entries to
+	// refer to ast2 instead.
+	f.walk(ast1, "prog", (*File).saveExport)
+	f.walk(ast2, "prog", (*File).saveExport2)
+
+	f.Comments = ast1.Comments
+	f.AST = ast2
+}
+
+// Like ast.CommentGroup's Text method but preserves
+// leading blank lines, so that line numbers line up.
+func commentText(g *ast.CommentGroup) string {
+	if g == nil {
+		return ""
+	}
+	var pieces []string
+	for _, com := range g.List {
+		c := string(com.Text)
+		// Remove comment markers.
+		// The parser has given us exactly the comment text.
+		switch c[1] {
+		case '/':
+			//-style comment (no newline at the end)
+			c = c[2:] + "\n"
+		case '*':
+			/*-style comment */
+			c = c[2 : len(c)-2]
+		}
+		pieces = append(pieces, c)
+	}
+	return strings.Join(pieces, "")
+}
+
+// Save references to C.xxx for later processing.
+func (f *File) saveRef(x interface{}, context string) {
+	n, ok := x.(*ast.Expr)
+	if !ok {
+		return
+	}
+	if sel, ok := (*n).(*ast.SelectorExpr); ok {
+		// For now, assume that the only instance of capital C is
+		// when used as the imported package identifier.
+		// The parser should take care of scoping in the future,
+		// so that we will be able to distinguish a "top-level C"
+		// from a local C.
+		if l, ok := sel.X.(*ast.Ident); ok && l.Name == "C" {
+			if context == "as2" {
+				context = "expr"
+			}
+			if context == "embed-type" {
+				error_(sel.Pos(), "cannot embed C type")
+			}
+			goname := sel.Sel.Name
+			if goname == "errno" {
+				error_(sel.Pos(), "cannot refer to errno directly; see documentation")
+				return
+			}
+			if goname == "_CMalloc" {
+				error_(sel.Pos(), "cannot refer to C._CMalloc; use C.malloc")
+				return
+			}
+			if goname == "malloc" {
+				goname = "_CMalloc"
+			}
+			name := f.Name[goname]
+			if name == nil {
+				name = &Name{
+					Go: goname,
+				}
+				f.Name[goname] = name
+			}
+			f.Ref = append(f.Ref, &Ref{
+				Name:    name,
+				Expr:    n,
+				Context: context,
+			})
+			return
+		}
+	}
+}
+
+// If a function should be exported add it to ExpFunc.
+func (f *File) saveExport(x interface{}, context string) {
+	n, ok := x.(*ast.FuncDecl)
+	if !ok {
+		return
+	}
+
+	if n.Doc == nil {
+		return
+	}
+	for _, c := range n.Doc.List {
+		if !strings.HasPrefix(string(c.Text), "//export ") {
+			continue
+		}
+
+		name := strings.TrimSpace(string(c.Text[9:]))
+		if name == "" {
+			error_(c.Pos(), "export missing name")
+		}
+
+		if name != n.Name.Name {
+			error_(c.Pos(), "export comment has wrong name %q, want %q", name, n.Name.Name)
+		}
+
+		f.ExpFunc = append(f.ExpFunc, &ExpFunc{
+			Func:    n,
+			ExpName: name,
+		})
+		break
+	}
+}
+
+// Make f.ExpFunc[i] point at the Func from this AST instead of the other one.
+func (f *File) saveExport2(x interface{}, context string) {
+	n, ok := x.(*ast.FuncDecl)
+	if !ok {
+		return
+	}
+
+	for _, exp := range f.ExpFunc {
+		if exp.Func.Name.Name == n.Name.Name {
+			exp.Func = n
+			break
+		}
+	}
+}
+
+// walk walks the AST x, calling visit(f, x, context) for each node.
+func (f *File) walk(x interface{}, context string, visit func(*File, interface{}, string)) {
+	visit(f, x, context)
+	switch n := x.(type) {
+	case *ast.Expr:
+		f.walk(*n, context, visit)
+
+	// everything else just recurs
+	default:
+		error_(token.NoPos, "unexpected type %T in walk", x, visit)
+		panic("unexpected type")
+
+	case nil:
+
+	// These are ordered and grouped to match ../../pkg/go/ast/ast.go
+	case *ast.Field:
+		if len(n.Names) == 0 && context == "field" {
+			f.walk(&n.Type, "embed-type", visit)
+		} else {
+			f.walk(&n.Type, "type", visit)
+		}
+	case *ast.FieldList:
+		for _, field := range n.List {
+			f.walk(field, context, visit)
+		}
+	case *ast.BadExpr:
+	case *ast.Ident:
+	case *ast.Ellipsis:
+	case *ast.BasicLit:
+	case *ast.FuncLit:
+		f.walk(n.Type, "type", visit)
+		f.walk(n.Body, "stmt", visit)
+	case *ast.CompositeLit:
+		f.walk(&n.Type, "type", visit)
+		f.walk(n.Elts, "expr", visit)
+	case *ast.ParenExpr:
+		f.walk(&n.X, context, visit)
+	case *ast.SelectorExpr:
+		f.walk(&n.X, "selector", visit)
+	case *ast.IndexExpr:
+		f.walk(&n.X, "expr", visit)
+		f.walk(&n.Index, "expr", visit)
+	case *ast.SliceExpr:
+		f.walk(&n.X, "expr", visit)
+		if n.Low != nil {
+			f.walk(&n.Low, "expr", visit)
+		}
+		if n.High != nil {
+			f.walk(&n.High, "expr", visit)
+		}
+	case *ast.TypeAssertExpr:
+		f.walk(&n.X, "expr", visit)
+		f.walk(&n.Type, "type", visit)
+	case *ast.CallExpr:
+		if context == "as2" {
+			f.walk(&n.Fun, "call2", visit)
+		} else {
+			f.walk(&n.Fun, "call", visit)
+		}
+		f.walk(n.Args, "expr", visit)
+	case *ast.StarExpr:
+		f.walk(&n.X, context, visit)
+	case *ast.UnaryExpr:
+		f.walk(&n.X, "expr", visit)
+	case *ast.BinaryExpr:
+		f.walk(&n.X, "expr", visit)
+		f.walk(&n.Y, "expr", visit)
+	case *ast.KeyValueExpr:
+		f.walk(&n.Key, "expr", visit)
+		f.walk(&n.Value, "expr", visit)
+
+	case *ast.ArrayType:
+		f.walk(&n.Len, "expr", visit)
+		f.walk(&n.Elt, "type", visit)
+	case *ast.StructType:
+		f.walk(n.Fields, "field", visit)
+	case *ast.FuncType:
+		f.walk(n.Params, "param", visit)
+		if n.Results != nil {
+			f.walk(n.Results, "param", visit)
+		}
+	case *ast.InterfaceType:
+		f.walk(n.Methods, "field", visit)
+	case *ast.MapType:
+		f.walk(&n.Key, "type", visit)
+		f.walk(&n.Value, "type", visit)
+	case *ast.ChanType:
+		f.walk(&n.Value, "type", visit)
+
+	case *ast.BadStmt:
+	case *ast.DeclStmt:
+		f.walk(n.Decl, "decl", visit)
+	case *ast.EmptyStmt:
+	case *ast.LabeledStmt:
+		f.walk(n.Stmt, "stmt", visit)
+	case *ast.ExprStmt:
+		f.walk(&n.X, "expr", visit)
+	case *ast.SendStmt:
+		f.walk(&n.Chan, "expr", visit)
+		f.walk(&n.Value, "expr", visit)
+	case *ast.IncDecStmt:
+		f.walk(&n.X, "expr", visit)
+	case *ast.AssignStmt:
+		f.walk(n.Lhs, "expr", visit)
+		if len(n.Lhs) == 2 && len(n.Rhs) == 1 {
+			f.walk(n.Rhs, "as2", visit)
+		} else {
+			f.walk(n.Rhs, "expr", visit)
+		}
+	case *ast.GoStmt:
+		f.walk(n.Call, "expr", visit)
+	case *ast.DeferStmt:
+		f.walk(n.Call, "expr", visit)
+	case *ast.ReturnStmt:
+		f.walk(n.Results, "expr", visit)
+	case *ast.BranchStmt:
+	case *ast.BlockStmt:
+		f.walk(n.List, context, visit)
+	case *ast.IfStmt:
+		f.walk(n.Init, "stmt", visit)
+		f.walk(&n.Cond, "expr", visit)
+		f.walk(n.Body, "stmt", visit)
+		f.walk(n.Else, "stmt", visit)
+	case *ast.CaseClause:
+		if context == "typeswitch" {
+			context = "type"
+		} else {
+			context = "expr"
+		}
+		f.walk(n.List, context, visit)
+		f.walk(n.Body, "stmt", visit)
+	case *ast.SwitchStmt:
+		f.walk(n.Init, "stmt", visit)
+		f.walk(&n.Tag, "expr", visit)
+		f.walk(n.Body, "switch", visit)
+	case *ast.TypeSwitchStmt:
+		f.walk(n.Init, "stmt", visit)
+		f.walk(n.Assign, "stmt", visit)
+		f.walk(n.Body, "typeswitch", visit)
+	case *ast.CommClause:
+		f.walk(n.Comm, "stmt", visit)
+		f.walk(n.Body, "stmt", visit)
+	case *ast.SelectStmt:
+		f.walk(n.Body, "stmt", visit)
+	case *ast.ForStmt:
+		f.walk(n.Init, "stmt", visit)
+		f.walk(&n.Cond, "expr", visit)
+		f.walk(n.Post, "stmt", visit)
+		f.walk(n.Body, "stmt", visit)
+	case *ast.RangeStmt:
+		f.walk(&n.Key, "expr", visit)
+		f.walk(&n.Value, "expr", visit)
+		f.walk(&n.X, "expr", visit)
+		f.walk(n.Body, "stmt", visit)
+
+	case *ast.ImportSpec:
+	case *ast.ValueSpec:
+		f.walk(&n.Type, "type", visit)
+		f.walk(n.Values, "expr", visit)
+	case *ast.TypeSpec:
+		f.walk(&n.Type, "type", visit)
+
+	case *ast.BadDecl:
+	case *ast.GenDecl:
+		f.walk(n.Specs, "spec", visit)
+	case *ast.FuncDecl:
+		if n.Recv != nil {
+			f.walk(n.Recv, "param", visit)
+		}
+		f.walk(n.Type, "type", visit)
+		if n.Body != nil {
+			f.walk(n.Body, "stmt", visit)
+		}
+
+	case *ast.File:
+		f.walk(n.Decls, "decl", visit)
+
+	case *ast.Package:
+		for _, file := range n.Files {
+			f.walk(file, "file", visit)
+		}
+
+	case []ast.Decl:
+		for _, d := range n {
+			f.walk(d, context, visit)
+		}
+	case []ast.Expr:
+		for i := range n {
+			f.walk(&n[i], context, visit)
+		}
+	case []ast.Stmt:
+		for _, s := range n {
+			f.walk(s, context, visit)
+		}
+	case []ast.Spec:
+		for _, s := range n {
+			f.walk(s, context, visit)
+		}
+	}
+}

libgo/go/cmd/cgo/doc.go

@@ -0,0 +1,748 @@
+// 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.
+
+/*
+
+Cgo enables the creation of Go packages that call C code.
+
+Using cgo with the go command
+
+To use cgo write normal Go code that imports a pseudo-package "C".
+The Go code can then refer to types such as C.size_t, variables such
+as C.stdout, or functions such as C.putchar.
+
+If the import of "C" is immediately preceded by a comment, that
+comment, called the preamble, is used as a header when compiling
+the C parts of the package.  For example:
+
+	// #include <stdio.h>
+	// #include <errno.h>
+	import "C"
+
+See $GOROOT/misc/cgo/stdio and $GOROOT/misc/cgo/gmp for examples.  See
+"C? Go? Cgo!" for an introduction to using cgo:
+http://golang.org/doc/articles/c_go_cgo.html.
+
+CFLAGS, CPPFLAGS, CXXFLAGS and LDFLAGS may be defined with pseudo #cgo
+directives within these comments to tweak the behavior of the C or C++
+compiler.  Values defined in multiple directives are concatenated
+together.  The directive can include a list of build constraints limiting its
+effect to systems satisfying one of the constraints
+(see http://golang.org/pkg/go/build/#hdr-Build_Constraints for details about the constraint syntax).
+For example:
+
+	// #cgo CFLAGS: -DPNG_DEBUG=1
+	// #cgo amd64 386 CFLAGS: -DX86=1
+	// #cgo LDFLAGS: -lpng
+	// #include <png.h>
+	import "C"
+
+Alternatively, CPPFLAGS and LDFLAGS may be obtained via the pkg-config
+tool using a '#cgo pkg-config:' directive followed by the package names.
+For example:
+
+	// #cgo pkg-config: png cairo
+	// #include <png.h>
+	import "C"
+
+When building, the CGO_CFLAGS, CGO_CPPFLAGS, CGO_CXXFLAGS and
+CGO_LDFLAGS environment variables are added to the flags derived from
+these directives.  Package-specific flags should be set using the
+directives, not the environment variables, so that builds work in
+unmodified environments.
+
+All the cgo CPPFLAGS and CFLAGS directives in a package are concatenated and
+used to compile C files in that package.  All the CPPFLAGS and CXXFLAGS
+directives in a package are concatenated and used to compile C++ files in that
+package.  All the LDFLAGS directives in any package in the program are
+concatenated and used at link time.  All the pkg-config directives are
+concatenated and sent to pkg-config simultaneously to add to each appropriate
+set of command-line flags.
+
+When the Go tool sees that one or more Go files use the special import
+"C", it will look for other non-Go files in the directory and compile
+them as part of the Go package.  Any .c, .s, or .S files will be
+compiled with the C compiler.  Any .cc, .cpp, or .cxx files will be
+compiled with the C++ compiler.  Any .h, .hh, .hpp, or .hxx files will
+not be compiled separately, but, if these header files are changed,
+the C and C++ files will be recompiled.  The default C and C++
+compilers may be changed by the CC and CXX environment variables,
+respectively; those environment variables may include command line
+options.
+
+To enable cgo during cross compiling builds, set the CGO_ENABLED
+environment variable to 1 when building the Go tools with make.bash.
+Also, set CC_FOR_TARGET to the C cross compiler for the target.  CC will
+be used for compiling for the host.
+
+After the Go tools are built, when running the go command, CC_FOR_TARGET is
+ignored.  The value of CC_FOR_TARGET when running make.bash is the default
+compiler.  However, you can set the environment variable CC, not CC_FOR_TARGET,
+to control the compiler when running the go tool.
+
+CXX_FOR_TARGET works in a similar way for C++ code.
+
+Go references to C
+
+Within the Go file, C's struct field names that are keywords in Go
+can be accessed by prefixing them with an underscore: if x points at a C
+struct with a field named "type", x._type accesses the field.
+C struct fields that cannot be expressed in Go, such as bit fields
+or misaligned data, are omitted in the Go struct, replaced by
+appropriate padding to reach the next field or the end of the struct.
+
+The standard C numeric types are available under the names
+C.char, C.schar (signed char), C.uchar (unsigned char),
+C.short, C.ushort (unsigned short), C.int, C.uint (unsigned int),
+C.long, C.ulong (unsigned long), C.longlong (long long),
+C.ulonglong (unsigned long long), C.float, C.double.
+The C type void* is represented by Go's unsafe.Pointer.
+
+To access a struct, union, or enum type directly, prefix it with
+struct_, union_, or enum_, as in C.struct_stat.
+
+As Go doesn't have support for C's union type in the general case,
+C's union types are represented as a Go byte array with the same length.
+
+Go structs cannot embed fields with C types.
+
+Cgo translates C types into equivalent unexported Go types.
+Because the translations are unexported, a Go package should not
+expose C types in its exported API: a C type used in one Go package
+is different from the same C type used in another.
+
+Any C function (even void functions) may be called in a multiple
+assignment context to retrieve both the return value (if any) and the
+C errno variable as an error (use _ to skip the result value if the
+function returns void).  For example:
+
+	n, err := C.sqrt(-1)
+	_, err := C.voidFunc()
+
+Calling C function pointers is currently not supported, however you can
+declare Go variables which hold C function pointers and pass them
+back and forth between Go and C. C code may call function pointers
+received from Go. For example:
+
+	package main
+
+	// typedef int (*intFunc) ();
+	//
+	// int
+	// bridge_int_func(intFunc f)
+	// {
+	//		return f();
+	// }
+	//
+	// int fortytwo()
+	// {
+	//	    return 42;
+	// }
+	import "C"
+	import "fmt"
+
+	func main() {
+		f := C.intFunc(C.fortytwo)
+		fmt.Println(int(C.bridge_int_func(f)))
+		// Output: 42
+	}
+
+In C, a function argument written as a fixed size array
+actually requires a pointer to the first element of the array.
+C compilers are aware of this calling convention and adjust
+the call accordingly, but Go cannot.  In Go, you must pass
+the pointer to the first element explicitly: C.f(&x[0]).
+
+A few special functions convert between Go and C types
+by making copies of the data.  In pseudo-Go definitions:
+
+	// Go string to C string
+	// The C string is allocated in the C heap using malloc.
+	// It is the caller's responsibility to arrange for it to be
+	// freed, such as by calling C.free (be sure to include stdlib.h
+	// if C.free is needed).
+	func C.CString(string) *C.char
+
+	// C string to Go string
+	func C.GoString(*C.char) string
+
+	// C string, length to Go string
+	func C.GoStringN(*C.char, C.int) string
+
+	// C pointer, length to Go []byte
+	func C.GoBytes(unsafe.Pointer, C.int) []byte
+
+C references to Go
+
+Go functions can be exported for use by C code in the following way:
+
+	//export MyFunction
+	func MyFunction(arg1, arg2 int, arg3 string) int64 {...}
+
+	//export MyFunction2
+	func MyFunction2(arg1, arg2 int, arg3 string) (int64, *C.char) {...}
+
+They will be available in the C code as:
+
+	extern int64 MyFunction(int arg1, int arg2, GoString arg3);
+	extern struct MyFunction2_return MyFunction2(int arg1, int arg2, GoString arg3);
+
+found in the _cgo_export.h generated header, after any preambles
+copied from the cgo input files. Functions with multiple
+return values are mapped to functions returning a struct.
+Not all Go types can be mapped to C types in a useful way.
+
+Using //export in a file places a restriction on the preamble:
+since it is copied into two different C output files, it must not
+contain any definitions, only declarations. Definitions must be
+placed in preambles in other files, or in C source files.
+
+Using cgo directly
+
+Usage:
+	go tool cgo [cgo options] [-- compiler options] file.go
+
+Cgo transforms the input file.go into four output files: two Go source
+files, a C file for 6c (or 8c or 5c), and a C file for gcc.
+
+The compiler options are passed through uninterpreted when
+invoking the C compiler to compile the C parts of the package.
+
+The following options are available when running cgo directly:
+
+	-dynimport file
+		Write list of symbols imported by file. Write to
+		-dynout argument or to standard output. Used by go
+		build when building a cgo package.
+	-dynout file
+		Write -dynimport output to file.
+	-dynlinker
+		Write dynamic linker as part of -dynimport output.
+	-godefs
+		Write out input file in Go syntax replacing C package
+		names with real values. Used to generate files in the
+		syscall package when bootstrapping a new target.
+	-cdefs
+		Like -godefs, but write file in C syntax.
+		Used to generate files in the runtime package when
+		bootstrapping a new target.
+	-objdir directory
+		Put all generated files in directory.
+	-gccgo
+		Generate output for the gccgo compiler rather than the
+		gc compiler.
+	-gccgoprefix prefix
+		The -fgo-prefix option to be used with gccgo.
+	-gccgopkgpath path
+		The -fgo-pkgpath option to be used with gccgo.
+	-import_runtime_cgo
+		If set (which it is by default) import runtime/cgo in
+		generated output.
+	-import_syscall
+		If set (which it is by default) import syscall in
+		generated output.
+	-debug-define
+		Debugging option. Print #defines.
+	-debug-gcc
+		Debugging option. Trace C compiler execution and output.
+*/
+package main
+
+/*
+Implementation details.
+
+Cgo provides a way for Go programs to call C code linked into the same
+address space. This comment explains the operation of cgo.
+
+Cgo reads a set of Go source files and looks for statements saying
+import "C". If the import has a doc comment, that comment is
+taken as literal C code to be used as a preamble to any C code
+generated by cgo. A typical preamble #includes necessary definitions:
+
+	// #include <stdio.h>
+	import "C"
+
+For more details about the usage of cgo, see the documentation
+comment at the top of this file.
+
+Understanding C
+
+Cgo scans the Go source files that import "C" for uses of that
+package, such as C.puts. It collects all such identifiers. The next
+step is to determine each kind of name. In C.xxx the xxx might refer
+to a type, a function, a constant, or a global variable. Cgo must
+decide which.
+
+The obvious thing for cgo to do is to process the preamble, expanding
+#includes and processing the corresponding C code. That would require
+a full C parser and type checker that was also aware of any extensions
+known to the system compiler (for example, all the GNU C extensions) as
+well as the system-specific header locations and system-specific
+pre-#defined macros. This is certainly possible to do, but it is an
+enormous amount of work.
+
+Cgo takes a different approach. It determines the meaning of C
+identifiers not by parsing C code but by feeding carefully constructed
+programs into the system C compiler and interpreting the generated
+error messages, debug information, and object files. In practice,
+parsing these is significantly less work and more robust than parsing
+C source.
+
+Cgo first invokes gcc -E -dM on the preamble, in order to find out
+about simple #defines for constants and the like. These are recorded
+for later use.
+
+Next, cgo needs to identify the kinds for each identifier. For the
+identifiers C.foo and C.bar, cgo generates this C program:
+
+	<preamble>
+	#line 1 "not-declared"
+	void __cgo_f_xxx_1(void) { __typeof__(foo) *__cgo_undefined__; }
+	#line 1 "not-type"
+	void __cgo_f_xxx_2(void) { foo *__cgo_undefined__; }
+	#line 1 "not-const"
+	void __cgo_f_xxx_3(void) { enum { __cgo_undefined__ = (foo)*1 }; }
+	#line 2 "not-declared"
+	void __cgo_f_xxx_1(void) { __typeof__(bar) *__cgo_undefined__; }
+	#line 2 "not-type"
+	void __cgo_f_xxx_2(void) { bar *__cgo_undefined__; }
+	#line 2 "not-const"
+	void __cgo_f_xxx_3(void) { enum { __cgo_undefined__ = (bar)*1 }; }
+
+This program will not compile, but cgo can use the presence or absence
+of an error message on a given line to deduce the information it
+needs. The program is syntactically valid regardless of whether each
+name is a type or an ordinary identifier, so there will be no syntax
+errors that might stop parsing early.
+
+An error on not-declared:1 indicates that foo is undeclared.
+An error on not-type:1 indicates that foo is not a type (if declared at all, it is an identifier).
+An error on not-const:1 indicates that foo is not an integer constant.
+
+The line number specifies the name involved. In the example, 1 is foo and 2 is bar.
+
+Next, cgo must learn the details of each type, variable, function, or
+constant. It can do this by reading object files. If cgo has decided
+that t1 is a type, v2 and v3 are variables or functions, and c4, c5,
+and c6 are constants, it generates:
+
+	<preamble>
+	__typeof__(t1) *__cgo__1;
+	__typeof__(v2) *__cgo__2;
+	__typeof__(v3) *__cgo__3;
+	__typeof__(c4) *__cgo__4;
+	enum { __cgo_enum__4 = c4 };
+	__typeof__(c5) *__cgo__5;
+	enum { __cgo_enum__5 = c5 };
+	__typeof__(c6) *__cgo__6;
+	enum { __cgo_enum__6 = c6 };
+
+	long long __cgo_debug_data[] = {
+		0, // t1
+		0, // v2
+		0, // v3
+		c4,
+		c5,
+		c6,
+		1
+	};
+
+and again invokes the system C compiler, to produce an object file
+containing debug information. Cgo parses the DWARF debug information
+for __cgo__N to learn the type of each identifier. (The types also
+distinguish functions from global variables.) If using a standard gcc,
+cgo can parse the DWARF debug information for the __cgo_enum__N to
+learn the identifier's value. The LLVM-based gcc on OS X emits
+incomplete DWARF information for enums; in that case cgo reads the
+constant values from the __cgo_debug_data from the object file's data
+segment.
+
+At this point cgo knows the meaning of each C.xxx well enough to start
+the translation process.
+
+Translating Go
+
+[The rest of this comment refers to 6g and 6c, the Go and C compilers
+that are part of the amd64 port of the gc Go toolchain. Everything here
+applies to another architecture's compilers as well.]
+
+Given the input Go files x.go and y.go, cgo generates these source
+files:
+
+	x.cgo1.go       # for 6g
+	y.cgo1.go       # for 6g
+	_cgo_gotypes.go # for 6g
+	_cgo_defun.c    # for 6c
+	x.cgo2.c        # for gcc
+	y.cgo2.c        # for gcc
+	_cgo_export.c   # for gcc
+	_cgo_main.c     # for gcc
+
+The file x.cgo1.go is a copy of x.go with the import "C" removed and
+references to C.xxx replaced with names like _Cfunc_xxx or _Ctype_xxx.
+The definitions of those identifiers, written as Go functions, types,
+or variables, are provided in _cgo_gotypes.go.
+
+Here is a _cgo_gotypes.go containing definitions for C.flush (provided
+in the preamble) and C.puts (from stdio):
+
+	type _Ctype_char int8
+	type _Ctype_int int32
+	type _Ctype_void [0]byte
+
+	func _Cfunc_CString(string) *_Ctype_char
+	func _Cfunc_flush() _Ctype_void
+	func _Cfunc_puts(*_Ctype_char) _Ctype_int
+
+For functions, cgo only writes an external declaration in the Go
+output. The implementation is in a combination of C for 6c (meaning
+any gc-toolchain compiler) and C for gcc.
+
+The 6c file contains the definitions of the functions. They all have
+similar bodies that invoke runtime·cgocall to make a switch from the
+Go runtime world to the system C (GCC-based) world.
+
+For example, here is the definition of _Cfunc_puts:
+
+	void _cgo_be59f0f25121_Cfunc_puts(void*);
+
+	void
+	·_Cfunc_puts(struct{uint8 x[1];}p)
+	{
+		runtime·cgocall(_cgo_be59f0f25121_Cfunc_puts, &p);
+	}
+
+The hexadecimal number is a hash of cgo's input, chosen to be
+deterministic yet unlikely to collide with other uses. The actual
+function _cgo_be59f0f25121_Cfunc_puts is implemented in a C source
+file compiled by gcc, the file x.cgo2.c:
+
+	void
+	_cgo_be59f0f25121_Cfunc_puts(void *v)
+	{
+		struct {
+			char* p0;
+			int r;
+			char __pad12[4];
+		} __attribute__((__packed__, __gcc_struct__)) *a = v;
+		a->r = puts((void*)a->p0);
+	}
+
+It extracts the arguments from the pointer to _Cfunc_puts's argument
+frame, invokes the system C function (in this case, puts), stores the
+result in the frame, and returns.
+
+Linking
+
+Once the _cgo_export.c and *.cgo2.c files have been compiled with gcc,
+they need to be linked into the final binary, along with the libraries
+they might depend on (in the case of puts, stdio). 6l has been
+extended to understand basic ELF files, but it does not understand ELF
+in the full complexity that modern C libraries embrace, so it cannot
+in general generate direct references to the system libraries.
+
+Instead, the build process generates an object file using dynamic
+linkage to the desired libraries. The main function is provided by
+_cgo_main.c:
+
+	int main() { return 0; }
+	void crosscall2(void(*fn)(void*, int), void *a, int c) { }
+	void _cgo_allocate(void *a, int c) { }
+	void _cgo_panic(void *a, int c) { }
+
+The extra functions here are stubs to satisfy the references in the C
+code generated for gcc. The build process links this stub, along with
+_cgo_export.c and *.cgo2.c, into a dynamic executable and then lets
+cgo examine the executable. Cgo records the list of shared library
+references and resolved names and writes them into a new file
+_cgo_import.c, which looks like:
+
+	#pragma cgo_dynamic_linker "/lib64/ld-linux-x86-64.so.2"
+	#pragma cgo_import_dynamic puts puts#GLIBC_2.2.5 "libc.so.6"
+	#pragma cgo_import_dynamic __libc_start_main __libc_start_main#GLIBC_2.2.5 "libc.so.6"
+	#pragma cgo_import_dynamic stdout stdout#GLIBC_2.2.5 "libc.so.6"
+	#pragma cgo_import_dynamic fflush fflush#GLIBC_2.2.5 "libc.so.6"
+	#pragma cgo_import_dynamic _ _ "libpthread.so.0"
+	#pragma cgo_import_dynamic _ _ "libc.so.6"
+
+In the end, the compiled Go package, which will eventually be
+presented to 6l as part of a larger program, contains:
+
+	_go_.6        # 6g-compiled object for _cgo_gotypes.go *.cgo1.go
+	_cgo_defun.6  # 6c-compiled object for _cgo_defun.c
+	_all.o        # gcc-compiled object for _cgo_export.c, *.cgo2.c
+	_cgo_import.6 # 6c-compiled object for _cgo_import.c
+
+The final program will be a dynamic executable, so that 6l can avoid
+needing to process arbitrary .o files. It only needs to process the .o
+files generated from C files that cgo writes, and those are much more
+limited in the ELF or other features that they use.
+
+In essence, the _cgo_import.6 file includes the extra linking
+directives that 6l is not sophisticated enough to derive from _all.o
+on its own. Similarly, the _all.o uses dynamic references to real
+system object code because 6l is not sophisticated enough to process
+the real code.
+
+The main benefits of this system are that 6l remains relatively simple
+(it does not need to implement a complete ELF and Mach-O linker) and
+that gcc is not needed after the package is compiled. For example,
+package net uses cgo for access to name resolution functions provided
+by libc. Although gcc is needed to compile package net, gcc is not
+needed to link programs that import package net.
+
+Runtime
+
+When using cgo, Go must not assume that it owns all details of the
+process. In particular it needs to coordinate with C in the use of
+threads and thread-local storage. The runtime package, in its own
+(6c-compiled) C code, declares a few uninitialized (default bss)
+variables:
+
+	bool	runtime·iscgo;
+	void	(*libcgo_thread_start)(void*);
+	void	(*initcgo)(G*);
+
+Any package using cgo imports "runtime/cgo", which provides
+initializations for these variables. It sets iscgo to 1, initcgo to a
+gcc-compiled function that can be called early during program startup,
+and libcgo_thread_start to a gcc-compiled function that can be used to
+create a new thread, in place of the runtime's usual direct system
+calls.
+
+Internal and External Linking
+
+The text above describes "internal" linking, in which 6l parses and
+links host object files (ELF, Mach-O, PE, and so on) into the final
+executable itself. Keeping 6l simple means we cannot possibly
+implement the full semantics of the host linker, so the kinds of
+objects that can be linked directly into the binary is limited (other
+code can only be used as a dynamic library). On the other hand, when
+using internal linking, 6l can generate Go binaries by itself.
+
+In order to allow linking arbitrary object files without requiring
+dynamic libraries, cgo will soon support an "external" linking mode
+too. In external linking mode, 6l does not process any host object
+files. Instead, it collects all the Go code and writes a single go.o
+object file containing it. Then it invokes the host linker (usually
+gcc) to combine the go.o object file and any supporting non-Go code
+into a final executable. External linking avoids the dynamic library
+requirement but introduces a requirement that the host linker be
+present to create such a binary.
+
+Most builds both compile source code and invoke the linker to create a
+binary. When cgo is involved, the compile step already requires gcc, so
+it is not problematic for the link step to require gcc too.
+
+An important exception is builds using a pre-compiled copy of the
+standard library. In particular, package net uses cgo on most systems,
+and we want to preserve the ability to compile pure Go code that
+imports net without requiring gcc to be present at link time. (In this
+case, the dynamic library requirement is less significant, because the
+only library involved is libc.so, which can usually be assumed
+present.)
+
+This conflict between functionality and the gcc requirement means we
+must support both internal and external linking, depending on the
+circumstances: if net is the only cgo-using package, then internal
+linking is probably fine, but if other packages are involved, so that there
+are dependencies on libraries beyond libc, external linking is likely
+to work better. The compilation of a package records the relevant
+information to support both linking modes, leaving the decision
+to be made when linking the final binary.
+
+Linking Directives
+
+In either linking mode, package-specific directives must be passed
+through to 6l. These are communicated by writing #pragma directives
+in a C source file compiled by 6c. The directives are copied into the .6 object file
+and then processed by the linker.
+
+The directives are:
+
+#pragma cgo_import_dynamic <local> [<remote> ["<library>"]]
+
+	In internal linking mode, allow an unresolved reference to
+	<local>, assuming it will be resolved by a dynamic library
+	symbol. The optional <remote> specifies the symbol's name and
+	possibly version in the dynamic library, and the optional "<library>"
+	names the specific library where the symbol should be found.
+
+	In the <remote>, # or @ can be used to introduce a symbol version.
+
+	Examples:
+	#pragma cgo_import_dynamic puts
+	#pragma cgo_import_dynamic puts puts#GLIBC_2.2.5
+	#pragma cgo_import_dynamic puts puts#GLIBC_2.2.5 "libc.so.6"
+
+	A side effect of the cgo_import_dynamic directive with a
+	library is to make the final binary depend on that dynamic
+	library. To get the dependency without importing any specific
+	symbols, use _ for local and remote.
+
+	Example:
+	#pragma cgo_import_dynamic _ _ "libc.so.6"
+
+	For compatibility with current versions of SWIG,
+	#pragma dynimport is an alias for #pragma cgo_import_dynamic.
+
+#pragma cgo_dynamic_linker "<path>"
+
+	In internal linking mode, use "<path>" as the dynamic linker
+	in the final binary. This directive is only needed from one
+	package when constructing a binary; by convention it is
+	supplied by runtime/cgo.
+
+	Example:
+	#pragma cgo_dynamic_linker "/lib/ld-linux.so.2"
+
+#pragma cgo_export_dynamic <local> <remote>
+
+	In internal linking mode, put the Go symbol
+	named <local> into the program's exported symbol table as
+	<remote>, so that C code can refer to it by that name. This
+	mechanism makes it possible for C code to call back into Go or
+	to share Go's data.
+
+	For compatibility with current versions of SWIG,
+	#pragma dynexport is an alias for #pragma cgo_export_dynamic.
+
+#pragma cgo_import_static <local>
+
+	In external linking mode, allow unresolved references to
+	<local> in the go.o object file prepared for the host linker,
+	under the assumption that <local> will be supplied by the
+	other object files that will be linked with go.o.
+
+	Example:
+	#pragma cgo_import_static puts_wrapper
+
+#pragma cgo_export_static <local> <remote>
+
+	In external linking mode, put the Go symbol
+	named <local> into the program's exported symbol table as
+	<remote>, so that C code can refer to it by that name. This
+	mechanism makes it possible for C code to call back into Go or
+	to share Go's data.
+
+#pragma cgo_ldflag "<arg>"
+
+	In external linking mode, invoke the host linker (usually gcc)
+	with "<arg>" as a command-line argument following the .o files.
+	Note that the arguments are for "gcc", not "ld".
+
+	Example:
+	#pragma cgo_ldflag "-lpthread"
+	#pragma cgo_ldflag "-L/usr/local/sqlite3/lib"
+
+A package compiled with cgo will include directives for both
+internal and external linking; the linker will select the appropriate
+subset for the chosen linking mode.
+
+Example
+
+As a simple example, consider a package that uses cgo to call C.sin.
+The following code will be generated by cgo:
+
+	// compiled by 6g
+
+	type _Ctype_double float64
+	func _Cfunc_sin(_Ctype_double) _Ctype_double
+
+	// compiled by 6c
+
+	#pragma cgo_import_dynamic sin sin#GLIBC_2.2.5 "libm.so.6"
+
+	#pragma cgo_import_static _cgo_gcc_Cfunc_sin
+	#pragma cgo_ldflag "-lm"
+
+	void _cgo_gcc_Cfunc_sin(void*);
+
+	void
+	·_Cfunc_sin(struct{uint8 x[16];}p)
+	{
+		runtime·cgocall(_cgo_gcc_Cfunc_sin, &p);
+	}
+
+	// compiled by gcc, into foo.cgo2.o
+
+	void
+	_cgo_gcc_Cfunc_sin(void *v)
+	{
+		struct {
+			double p0;
+			double r;
+		} __attribute__((__packed__)) *a = v;
+		a->r = sin(a->p0);
+	}
+
+What happens at link time depends on whether the final binary is linked
+using the internal or external mode. If other packages are compiled in
+"external only" mode, then the final link will be an external one.
+Otherwise the link will be an internal one.
+
+The directives in the 6c-compiled file are used according to the kind
+of final link used.
+
+In internal mode, 6l itself processes all the host object files, in
+particular foo.cgo2.o. To do so, it uses the cgo_import_dynamic and
+cgo_dynamic_linker directives to learn that the otherwise undefined
+reference to sin in foo.cgo2.o should be rewritten to refer to the
+symbol sin with version GLIBC_2.2.5 from the dynamic library
+"libm.so.6", and the binary should request "/lib/ld-linux.so.2" as its
+runtime dynamic linker.
+
+In external mode, 6l does not process any host object files, in
+particular foo.cgo2.o. It links together the 6g- and 6c-generated
+object files, along with any other Go code, into a go.o file. While
+doing that, 6l will discover that there is no definition for
+_cgo_gcc_Cfunc_sin, referred to by the 6c-compiled source file. This
+is okay, because 6l also processes the cgo_import_static directive and
+knows that _cgo_gcc_Cfunc_sin is expected to be supplied by a host
+object file, so 6l does not treat the missing symbol as an error when
+creating go.o. Indeed, the definition for _cgo_gcc_Cfunc_sin will be
+provided to the host linker by foo2.cgo.o, which in turn will need the
+symbol 'sin'. 6l also processes the cgo_ldflag directives, so that it
+knows that the eventual host link command must include the -lm
+argument, so that the host linker will be able to find 'sin' in the
+math library.
+
+6l Command Line Interface
+
+The go command and any other Go-aware build systems invoke 6l
+to link a collection of packages into a single binary. By default, 6l will
+present the same interface it does today:
+
+	6l main.a
+
+produces a file named 6.out, even if 6l does so by invoking the host
+linker in external linking mode.
+
+By default, 6l will decide the linking mode as follows: if the only
+packages using cgo are those on a whitelist of standard library
+packages (net, os/user, runtime/cgo), 6l will use internal linking
+mode. Otherwise, there are non-standard cgo packages involved, and 6l
+will use external linking mode. The first rule means that a build of
+the godoc binary, which uses net but no other cgo, can run without
+needing gcc available. The second rule means that a build of a
+cgo-wrapped library like sqlite3 can generate a standalone executable
+instead of needing to refer to a dynamic library. The specific choice
+can be overridden using a command line flag: 6l -linkmode=internal or
+6l -linkmode=external.
+
+In an external link, 6l will create a temporary directory, write any
+host object files found in package archives to that directory (renamed
+to avoid conflicts), write the go.o file to that directory, and invoke
+the host linker. The default value for the host linker is $CC, split
+into fields, or else "gcc". The specific host linker command line can
+be overridden using command line flags: 6l -extld=clang
+-extldflags='-ggdb -O3'.  If any package in a build includes a .cc or
+other file compiled by the C++ compiler, the go tool will use the
+-extld option to set the host linker to the C++ compiler.
+
+These defaults mean that Go-aware build systems can ignore the linking
+changes and keep running plain '6l' and get reasonable results, but
+they can also control the linking details if desired.
+
+*/

libgo/go/cmd/cgo/godefs.go

@@ -0,0 +1,294 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/printer"
+	"go/token"
+	"os"
+	"strings"
+)
+
+// godefs returns the output for -godefs mode.
+func (p *Package) godefs(f *File, srcfile string) string {
+	var buf bytes.Buffer
+
+	fmt.Fprintf(&buf, "// Created by cgo -godefs - DO NOT EDIT\n")
+	fmt.Fprintf(&buf, "// %s\n", strings.Join(os.Args, " "))
+	fmt.Fprintf(&buf, "\n")
+
+	override := make(map[string]string)
+
+	// Allow source file to specify override mappings.
+	// For example, the socket data structures refer
+	// to in_addr and in_addr6 structs but we want to be
+	// able to treat them as byte arrays, so the godefs
+	// inputs in package syscall say
+	//
+	//	// +godefs map struct_in_addr [4]byte
+	//	// +godefs map struct_in_addr6 [16]byte
+	//
+	for _, g := range f.Comments {
+		for _, c := range g.List {
+			i := strings.Index(c.Text, "+godefs map")
+			if i < 0 {
+				continue
+			}
+			s := strings.TrimSpace(c.Text[i+len("+godefs map"):])
+			i = strings.Index(s, " ")
+			if i < 0 {
+				fmt.Fprintf(os.Stderr, "invalid +godefs map comment: %s\n", c.Text)
+				continue
+			}
+			override["_Ctype_"+strings.TrimSpace(s[:i])] = strings.TrimSpace(s[i:])
+		}
+	}
+	for _, n := range f.Name {
+		if s := override[n.Go]; s != "" {
+			override[n.Mangle] = s
+		}
+	}
+
+	// Otherwise, if the source file says type T C.whatever,
+	// use "T" as the mangling of C.whatever,
+	// except in the definition (handled at end of function).
+	refName := make(map[*ast.Expr]*Name)
+	for _, r := range f.Ref {
+		refName[r.Expr] = r.Name
+	}
+	for _, d := range f.AST.Decls {
+		d, ok := d.(*ast.GenDecl)
+		if !ok || d.Tok != token.TYPE {
+			continue
+		}
+		for _, s := range d.Specs {
+			s := s.(*ast.TypeSpec)
+			n := refName[&s.Type]
+			if n != nil && n.Mangle != "" {
+				override[n.Mangle] = s.Name.Name
+			}
+		}
+	}
+
+	// Extend overrides using typedefs:
+	// If we know that C.xxx should format as T
+	// and xxx is a typedef for yyy, make C.yyy format as T.
+	for typ, def := range typedef {
+		if new := override[typ]; new != "" {
+			if id, ok := def.Go.(*ast.Ident); ok {
+				override[id.Name] = new
+			}
+		}
+	}
+
+	// Apply overrides.
+	for old, new := range override {
+		if id := goIdent[old]; id != nil {
+			id.Name = new
+		}
+	}
+
+	// Any names still using the _C syntax are not going to compile,
+	// although in general we don't know whether they all made it
+	// into the file, so we can't warn here.
+	//
+	// The most common case is union types, which begin with
+	// _Ctype_union and for which typedef[name] is a Go byte
+	// array of the appropriate size (such as [4]byte).
+	// Substitute those union types with byte arrays.
+	for name, id := range goIdent {
+		if id.Name == name && strings.Contains(name, "_Ctype_union") {
+			if def := typedef[name]; def != nil {
+				id.Name = gofmt(def)
+			}
+		}
+	}
+
+	conf.Fprint(&buf, fset, f.AST)
+
+	return buf.String()
+}
+
+// cdefs returns the output for -cdefs mode.
+// The easiest way to do this is to translate the godefs Go to C.
+func (p *Package) cdefs(f *File, srcfile string) string {
+	godefsOutput := p.godefs(f, srcfile)
+
+	lines := strings.Split(godefsOutput, "\n")
+	lines[0] = "// Created by cgo -cdefs - DO NOT EDIT"
+
+	for i, line := range lines {
+		lines[i] = strings.TrimSpace(line)
+	}
+
+	var out bytes.Buffer
+	printf := func(format string, args ...interface{}) { fmt.Fprintf(&out, format, args...) }
+
+	didTypedef := false
+	for i := 0; i < len(lines); i++ {
+		line := lines[i]
+
+		// Delete
+		//	package x
+		if strings.HasPrefix(line, "package ") {
+			continue
+		}
+
+		// Convert
+		//	const (
+		//		A = 1
+		//		B = 2
+		//	)
+		//
+		// to
+		//
+		//	enum {
+		//		A = 1,
+		//		B = 2,
+		//	};
+		if line == "const (" {
+			printf("enum {\n")
+			for i++; i < len(lines) && lines[i] != ")"; i++ {
+				line = lines[i]
+				if line != "" {
+					printf("\t%s,", line)
+				}
+				printf("\n")
+			}
+			printf("};\n")
+			continue
+		}
+
+		// Convert
+		//	const A = 1
+		// to
+		//	enum { A = 1 };
+		if strings.HasPrefix(line, "const ") {
+			printf("enum { %s };\n", line[len("const "):])
+			continue
+		}
+
+		// On first type definition, typedef all the structs
+		// in case there are dependencies between them.
+		if !didTypedef && strings.HasPrefix(line, "type ") {
+			didTypedef = true
+			for _, line := range lines {
+				line = strings.TrimSpace(line)
+				if strings.HasPrefix(line, "type ") && strings.HasSuffix(line, " struct {") {
+					s := strings.TrimSuffix(strings.TrimPrefix(line, "type "), " struct {")
+					printf("typedef struct %s %s;\n", s, s)
+				}
+			}
+			printf("\n")
+			printf("#pragma pack on\n")
+			printf("\n")
+		}
+
+		// Convert
+		//	type T struct {
+		//		X int64
+		//		Y *int32
+		//		Z [4]byte
+		//	}
+		//
+		// to
+		//
+		//	struct T {
+		//		int64 X;
+		//		int32 *Y;
+		//		byte Z[4];
+		//	}
+		if strings.HasPrefix(line, "type ") && strings.HasSuffix(line, " struct {") {
+			if len(lines) > i+1 && lines[i+1] == "}" {
+				// do not output empty struct
+				i++
+				continue
+			}
+			s := line[len("type ") : len(line)-len(" struct {")]
+			printf("struct %s {\n", s)
+			for i++; i < len(lines) && lines[i] != "}"; i++ {
+				line := lines[i]
+				if line != "" {
+					f := strings.Fields(line)
+					if len(f) != 2 {
+						fmt.Fprintf(os.Stderr, "cgo: cannot parse struct field: %s\n", line)
+						nerrors++
+						continue
+					}
+					printf("\t%s;", cdecl(f[0], f[1]))
+				}
+				printf("\n")
+			}
+			printf("};\n")
+			continue
+		}
+
+		// Convert
+		//	type T int
+		// to
+		//	typedef int T;
+		if strings.HasPrefix(line, "type ") {
+			f := strings.Fields(line[len("type "):])
+			if len(f) != 2 {
+				fmt.Fprintf(os.Stderr, "cgo: cannot parse type definition: %s\n", line)
+				nerrors++
+				continue
+			}
+			printf("typedef\t%s;\n", cdecl(f[0], f[1]))
+			continue
+		}
+
+		printf("%s\n", line)
+	}
+
+	if didTypedef {
+		printf("\n")
+		printf("#pragma pack off\n")
+	}
+
+	return out.String()
+}
+
+// cdecl returns the C declaration for the given Go name and type.
+// It only handles the specific cases necessary for converting godefs output.
+func cdecl(name, typ string) string {
+	// X *[0]byte -> X *void
+	if strings.HasPrefix(typ, "*[0]") {
+		typ = "*void"
+	}
+	// X [4]byte -> X[4] byte
+	for strings.HasPrefix(typ, "[") {
+		i := strings.Index(typ, "]") + 1
+		name = name + typ[:i]
+		typ = typ[i:]
+	}
+	// X *byte -> *X byte
+	for strings.HasPrefix(typ, "*") {
+		name = "*" + name
+		typ = typ[1:]
+	}
+	// X T -> T X
+	// Handle the special case: 'unsafe.Pointer' is 'void *'
+	if typ == "unsafe.Pointer" {
+		typ = "void"
+		name = "*" + name
+	}
+	return typ + "\t" + name
+}
+
+var gofmtBuf bytes.Buffer
+
+// gofmt returns the gofmt-formatted string for an AST node.
+func gofmt(n interface{}) string {
+	gofmtBuf.Reset()
+	err := printer.Fprint(&gofmtBuf, fset, n)
+	if err != nil {
+		return "<" + err.Error() + ">"
+	}
+	return gofmtBuf.String()
+}

libgo/go/cmd/cgo/main.go

@@ -0,0 +1,360 @@
+// 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.
+
+// Cgo; see gmp.go for an overview.
+
+// TODO(rsc):
+//	Emit correct line number annotations.
+//	Make 6g understand the annotations.
+
+package main
+
+import (
+	"crypto/md5"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/printer"
+	"go/token"
+	"io"
+	"os"
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"sort"
+	"strings"
+)
+
+// A Package collects information about the package we're going to write.
+type Package struct {
+	PackageName string // name of package
+	PackagePath string
+	PtrSize     int64
+	IntSize     int64
+	GccOptions  []string
+	CgoFlags    map[string][]string // #cgo flags (CFLAGS, LDFLAGS)
+	Written     map[string]bool
+	Name        map[string]*Name // accumulated Name from Files
+	ExpFunc     []*ExpFunc       // accumulated ExpFunc from Files
+	Decl        []ast.Decl
+	GoFiles     []string // list of Go files
+	GccFiles    []string // list of gcc output files
+	Preamble    string   // collected preamble for _cgo_export.h
+}
+
+// A File collects information about a single Go input file.
+type File struct {
+	AST      *ast.File           // parsed AST
+	Comments []*ast.CommentGroup // comments from file
+	Package  string              // Package name
+	Preamble string              // C preamble (doc comment on import "C")
+	Ref      []*Ref              // all references to C.xxx in AST
+	ExpFunc  []*ExpFunc          // exported functions for this file
+	Name     map[string]*Name    // map from Go name to Name
+}
+
+func nameKeys(m map[string]*Name) []string {
+	var ks []string
+	for k := range m {
+		ks = append(ks, k)
+	}
+	sort.Strings(ks)
+	return ks
+}
+
+// A Ref refers to an expression of the form C.xxx in the AST.
+type Ref struct {
+	Name    *Name
+	Expr    *ast.Expr
+	Context string // "type", "expr", "call", or "call2"
+}
+
+func (r *Ref) Pos() token.Pos {
+	return (*r.Expr).Pos()
+}
+
+// A Name collects information about C.xxx.
+type Name struct {
+	Go       string // name used in Go referring to package C
+	Mangle   string // name used in generated Go
+	C        string // name used in C
+	Define   string // #define expansion
+	Kind     string // "const", "type", "var", "fpvar", "func", "not-type"
+	Type     *Type  // the type of xxx
+	FuncType *FuncType
+	AddError bool
+	Const    string // constant definition
+}
+
+// IsVar returns true if Kind is either "var" or "fpvar"
+func (n *Name) IsVar() bool {
+	return n.Kind == "var" || n.Kind == "fpvar"
+}
+
+// A ExpFunc is an exported function, callable from C.
+// Such functions are identified in the Go input file
+// by doc comments containing the line //export ExpName
+type ExpFunc struct {
+	Func    *ast.FuncDecl
+	ExpName string // name to use from C
+}
+
+// A TypeRepr contains the string representation of a type.
+type TypeRepr struct {
+	Repr       string
+	FormatArgs []interface{}
+}
+
+// A Type collects information about a type in both the C and Go worlds.
+type Type struct {
+	Size       int64
+	Align      int64
+	C          *TypeRepr
+	Go         ast.Expr
+	EnumValues map[string]int64
+	Typedef    string
+}
+
+// A FuncType collects information about a function type in both the C and Go worlds.
+type FuncType struct {
+	Params []*Type
+	Result *Type
+	Go     *ast.FuncType
+}
+
+func usage() {
+	fmt.Fprint(os.Stderr, "usage: cgo -- [compiler options] file.go ...\n")
+	flag.PrintDefaults()
+	os.Exit(2)
+}
+
+var ptrSizeMap = map[string]int64{
+	"386":   4,
+	"amd64": 8,
+	"arm":   4,
+	"ppc64": 8,
+	"ppc64le": 8,
+	"s390x": 8,
+}
+
+var intSizeMap = map[string]int64{
+	"386":   4,
+	"amd64": 8,
+	"arm":   4,
+	"ppc64": 8,
+	"ppc64le": 8,
+	"s390x": 8,
+}
+
+var cPrefix string
+
+var fset = token.NewFileSet()
+
+var dynobj = flag.String("dynimport", "", "if non-empty, print dynamic import data for that file")
+var dynout = flag.String("dynout", "", "write -dynobj output to this file")
+var dynlinker = flag.Bool("dynlinker", false, "record dynamic linker information in dynimport mode")
+
+// These flags are for bootstrapping a new Go implementation,
+// to generate Go and C headers that match the data layout and
+// constant values used in the host's C libraries and system calls.
+var godefs = flag.Bool("godefs", false, "for bootstrap: write Go definitions for C file to standard output")
+var cdefs = flag.Bool("cdefs", false, "for bootstrap: write C definitions for C file to standard output")
+var objDir = flag.String("objdir", "", "object directory")
+
+var gccgo = flag.Bool("gccgo", false, "generate files for use with gccgo")
+var gccgoprefix = flag.String("gccgoprefix", "", "-fgo-prefix option used with gccgo")
+var gccgopkgpath = flag.String("gccgopkgpath", "", "-fgo-pkgpath option used with gccgo")
+var importRuntimeCgo = flag.Bool("import_runtime_cgo", true, "import runtime/cgo in generated code")
+var importSyscall = flag.Bool("import_syscall", true, "import syscall in generated code")
+var goarch, goos string
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+
+	if *dynobj != "" {
+		// cgo -dynimport is essentially a separate helper command
+		// built into the cgo binary.  It scans a gcc-produced executable
+		// and dumps information about the imported symbols and the
+		// imported libraries.  The 'go build' rules for cgo prepare an
+		// appropriate executable and then use its import information
+		// instead of needing to make the linkers duplicate all the
+		// specialized knowledge gcc has about where to look for imported
+		// symbols and which ones to use.
+		dynimport(*dynobj)
+		return
+	}
+
+	if *godefs && *cdefs {
+		fmt.Fprintf(os.Stderr, "cgo: cannot use -cdefs and -godefs together\n")
+		os.Exit(2)
+	}
+
+	if *godefs || *cdefs {
+		// Generating definitions pulled from header files,
+		// to be checked into Go repositories.
+		// Line numbers are just noise.
+		conf.Mode &^= printer.SourcePos
+	}
+
+	args := flag.Args()
+	if len(args) < 1 {
+		usage()
+	}
+
+	// Find first arg that looks like a go file and assume everything before
+	// that are options to pass to gcc.
+	var i int
+	for i = len(args); i > 0; i-- {
+		if !strings.HasSuffix(args[i-1], ".go") {
+			break
+		}
+	}
+	if i == len(args) {
+		usage()
+	}
+
+	goFiles := args[i:]
+
+	p := newPackage(args[:i])
+
+	// Record CGO_LDFLAGS from the environment for external linking.
+	if ldflags := os.Getenv("CGO_LDFLAGS"); ldflags != "" {
+		args, err := splitQuoted(ldflags)
+		if err != nil {
+			fatalf("bad CGO_LDFLAGS: %q (%s)", ldflags, err)
+		}
+		p.addToFlag("LDFLAGS", args)
+	}
+
+	// Need a unique prefix for the global C symbols that
+	// we use to coordinate between gcc and ourselves.
+	// We already put _cgo_ at the beginning, so the main
+	// concern is other cgo wrappers for the same functions.
+	// Use the beginning of the md5 of the input to disambiguate.
+	h := md5.New()
+	for _, input := range goFiles {
+		f, err := os.Open(input)
+		if err != nil {
+			fatalf("%s", err)
+		}
+		io.Copy(h, f)
+		f.Close()
+	}
+	cPrefix = fmt.Sprintf("_%x", h.Sum(nil)[0:6])
+
+	fs := make([]*File, len(goFiles))
+	for i, input := range goFiles {
+		f := new(File)
+		f.ReadGo(input)
+		f.DiscardCgoDirectives()
+		fs[i] = f
+	}
+
+	if *objDir == "" {
+		// make sure that _obj directory exists, so that we can write
+		// all the output files there.
+		os.Mkdir("_obj", 0777)
+		*objDir = "_obj"
+	}
+	*objDir += string(filepath.Separator)
+
+	for i, input := range goFiles {
+		f := fs[i]
+		p.Translate(f)
+		for _, cref := range f.Ref {
+			switch cref.Context {
+			case "call", "call2":
+				if cref.Name.Kind != "type" {
+					break
+				}
+				*cref.Expr = cref.Name.Type.Go
+			}
+		}
+		if nerrors > 0 {
+			os.Exit(2)
+		}
+		pkg := f.Package
+		if dir := os.Getenv("CGOPKGPATH"); dir != "" {
+			pkg = filepath.Join(dir, pkg)
+		}
+		p.PackagePath = pkg
+		p.Record(f)
+		if *godefs {
+			os.Stdout.WriteString(p.godefs(f, input))
+		} else if *cdefs {
+			os.Stdout.WriteString(p.cdefs(f, input))
+		} else {
+			p.writeOutput(f, input)
+		}
+	}
+
+	if !*godefs && !*cdefs {
+		p.writeDefs()
+	}
+	if nerrors > 0 {
+		os.Exit(2)
+	}
+}
+
+// newPackage returns a new Package that will invoke
+// gcc with the additional arguments specified in args.
+func newPackage(args []string) *Package {
+	goarch = runtime.GOARCH
+	if s := os.Getenv("GOARCH"); s != "" {
+		goarch = s
+	}
+	goos = runtime.GOOS
+	if s := os.Getenv("GOOS"); s != "" {
+		goos = s
+	}
+	ptrSize := ptrSizeMap[goarch]
+	if ptrSize == 0 {
+		fatalf("unknown ptrSize for $GOARCH %q", goarch)
+	}
+	intSize := intSizeMap[goarch]
+	if intSize == 0 {
+		fatalf("unknown intSize for $GOARCH %q", goarch)
+	}
+
+	// Reset locale variables so gcc emits English errors [sic].
+	os.Setenv("LANG", "en_US.UTF-8")
+	os.Setenv("LC_ALL", "C")
+
+	p := &Package{
+		PtrSize:  ptrSize,
+		IntSize:  intSize,
+		CgoFlags: make(map[string][]string),
+		Written:  make(map[string]bool),
+	}
+	p.addToFlag("CFLAGS", args)
+	return p
+}
+
+// Record what needs to be recorded about f.
+func (p *Package) Record(f *File) {
+	if p.PackageName == "" {
+		p.PackageName = f.Package
+	} else if p.PackageName != f.Package {
+		error_(token.NoPos, "inconsistent package names: %s, %s", p.PackageName, f.Package)
+	}
+
+	if p.Name == nil {
+		p.Name = f.Name
+	} else {
+		for k, v := range f.Name {
+			if p.Name[k] == nil {
+				p.Name[k] = v
+			} else if !reflect.DeepEqual(p.Name[k], v) {
+				error_(token.NoPos, "inconsistent definitions for C.%s", fixGo(k))
+			}
+		}
+	}
+
+	if f.ExpFunc != nil {
+		p.ExpFunc = append(p.ExpFunc, f.ExpFunc...)
+		p.Preamble += "\n" + f.Preamble
+	}
+	p.Decl = append(p.Decl, f.AST.Decls...)
+}

libgo/go/cmd/cgo/util.go

@@ -0,0 +1,84 @@
+// 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.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/token"
+	"os"
+	"os/exec"
+)
+
+// run runs the command argv, feeding in stdin on standard input.
+// It returns the output to standard output and standard error.
+// ok indicates whether the command exited successfully.
+func run(stdin []byte, argv []string) (stdout, stderr []byte, ok bool) {
+	p := exec.Command(argv[0], argv[1:]...)
+	p.Stdin = bytes.NewReader(stdin)
+	var bout, berr bytes.Buffer
+	p.Stdout = &bout
+	p.Stderr = &berr
+	err := p.Run()
+	if _, ok := err.(*exec.ExitError); err != nil && !ok {
+		fatalf("%s", err)
+	}
+	ok = p.ProcessState.Success()
+	stdout, stderr = bout.Bytes(), berr.Bytes()
+	return
+}
+
+func lineno(pos token.Pos) string {
+	return fset.Position(pos).String()
+}
+
+// Die with an error message.
+func fatalf(msg string, args ...interface{}) {
+	// If we've already printed other errors, they might have
+	// caused the fatal condition.  Assume they're enough.
+	if nerrors == 0 {
+		fmt.Fprintf(os.Stderr, msg+"\n", args...)
+	}
+	os.Exit(2)
+}
+
+var nerrors int
+
+func error_(pos token.Pos, msg string, args ...interface{}) {
+	nerrors++
+	if pos.IsValid() {
+		fmt.Fprintf(os.Stderr, "%s: ", fset.Position(pos).String())
+	}
+	fmt.Fprintf(os.Stderr, msg, args...)
+	fmt.Fprintf(os.Stderr, "\n")
+}
+
+// isName returns true if s is a valid C identifier
+func isName(s string) bool {
+	for i, v := range s {
+		if v != '_' && (v < 'A' || v > 'Z') && (v < 'a' || v > 'z') && (v < '0' || v > '9') {
+			return false
+		}
+		if i == 0 && '0' <= v && v <= '9' {
+			return false
+		}
+	}
+	return s != ""
+}
+
+func creat(name string) *os.File {
+	f, err := os.Create(name)
+	if err != nil {
+		fatalf("%s", err)
+	}
+	return f
+}
+
+func slashToUnderscore(c rune) rune {
+	if c == '/' || c == '\\' || c == ':' {
+		c = '_'
+	}
+	return c
+}

libgo/go/cmd/go/bootstrap.go

@@ -0,0 +1,30 @@
+// Copyright 2012 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.
+
+// +build cmd_go_bootstrap
+
+// This code is compiled only into the bootstrap 'go' binary.
+// These stubs avoid importing packages with large dependency
+// trees, like the use of "net/http" in vcs.go.
+
+package main
+
+import (
+	"errors"
+	"io"
+)
+
+var errHTTP = errors.New("no http in bootstrap go command")
+
+func httpGET(url string) ([]byte, error) {
+	return nil, errHTTP
+}
+
+func httpsOrHTTP(importPath string) (string, io.ReadCloser, error) {
+	return "", nil, errHTTP
+}
+
+func parseMetaGoImports(r io.Reader) ([]metaImport, error) {
+	panic("unreachable")
+}

libgo/go/cmd/go/clean.go

@@ -0,0 +1,248 @@
+// Copyright 2012 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.
+
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var cmdClean = &Command{
+	UsageLine: "clean [-i] [-r] [-n] [-x] [build flags] [packages]",
+	Short:     "remove object files",
+	Long: `
+Clean removes object files from package source directories.
+The go command builds most objects in a temporary directory,
+so go clean is mainly concerned with object files left by other
+tools or by manual invocations of go build.
+
+Specifically, clean removes the following files from each of the
+source directories corresponding to the import paths:
+
+	_obj/            old object directory, left from Makefiles
+	_test/           old test directory, left from Makefiles
+	_testmain.go     old gotest file, left from Makefiles
+	test.out         old test log, left from Makefiles
+	build.out        old test log, left from Makefiles
+	*.[568ao]        object files, left from Makefiles
+
+	DIR(.exe)        from go build
+	DIR.test(.exe)   from go test -c
+	MAINFILE(.exe)   from go build MAINFILE.go
+	*.so             from SWIG
+
+In the list, DIR represents the final path element of the
+directory, and MAINFILE is the base name of any Go source
+file in the directory that is not included when building
+the package.
+
+The -i flag causes clean to remove the corresponding installed
+archive or binary (what 'go install' would create).
+
+The -n flag causes clean to print the remove commands it would execute,
+but not run them.
+
+The -r flag causes clean to be applied recursively to all the
+dependencies of the packages named by the import paths.
+
+The -x flag causes clean to print remove commands as it executes them.
+
+For more about build flags, see 'go help build'.
+
+For more about specifying packages, see 'go help packages'.
+	`,
+}
+
+var cleanI bool // clean -i flag
+var cleanR bool // clean -r flag
+
+func init() {
+	// break init cycle
+	cmdClean.Run = runClean
+
+	cmdClean.Flag.BoolVar(&cleanI, "i", false, "")
+	cmdClean.Flag.BoolVar(&cleanR, "r", false, "")
+	// -n and -x are important enough to be
+	// mentioned explicitly in the docs but they
+	// are part of the build flags.
+
+	addBuildFlags(cmdClean)
+}
+
+func runClean(cmd *Command, args []string) {
+	for _, pkg := range packagesAndErrors(args) {
+		clean(pkg)
+	}
+}
+
+var cleaned = map[*Package]bool{}
+
+// TODO: These are dregs left by Makefile-based builds.
+// Eventually, can stop deleting these.
+var cleanDir = map[string]bool{
+	"_test": true,
+	"_obj":  true,
+}
+
+var cleanFile = map[string]bool{
+	"_testmain.go": true,
+	"test.out":     true,
+	"build.out":    true,
+	"a.out":        true,
+}
+
+var cleanExt = map[string]bool{
+	".5":  true,
+	".6":  true,
+	".8":  true,
+	".a":  true,
+	".o":  true,
+	".so": true,
+}
+
+func clean(p *Package) {
+	if cleaned[p] {
+		return
+	}
+	cleaned[p] = true
+
+	if p.Dir == "" {
+		errorf("can't load package: %v", p.Error)
+		return
+	}
+	dirs, err := ioutil.ReadDir(p.Dir)
+	if err != nil {
+		errorf("go clean %s: %v", p.Dir, err)
+		return
+	}
+
+	var b builder
+	b.print = fmt.Print
+
+	packageFile := map[string]bool{}
+	if p.Name != "main" {
+		// Record which files are not in package main.
+		// The others are.
+		keep := func(list []string) {
+			for _, f := range list {
+				packageFile[f] = true
+			}
+		}
+		keep(p.GoFiles)
+		keep(p.CgoFiles)
+		keep(p.TestGoFiles)
+		keep(p.XTestGoFiles)
+	}
+
+	_, elem := filepath.Split(p.Dir)
+	var allRemove []string
+
+	// Remove dir-named executable only if this is package main.
+	if p.Name == "main" {
+		allRemove = append(allRemove,
+			elem,
+			elem+".exe",
+		)
+	}
+
+	// Remove package test executables.
+	allRemove = append(allRemove,
+		elem+".test",
+		elem+".test.exe",
+	)
+
+	// Remove a potential executable for each .go file in the directory that
+	// is not part of the directory's package.
+	for _, dir := range dirs {
+		name := dir.Name()
+		if packageFile[name] {
+			continue
+		}
+		if !dir.IsDir() && strings.HasSuffix(name, ".go") {
+			// TODO(adg,rsc): check that this .go file is actually
+			// in "package main", and therefore capable of building
+			// to an executable file.
+			base := name[:len(name)-len(".go")]
+			allRemove = append(allRemove, base, base+".exe")
+		}
+	}
+
+	if buildN || buildX {
+		b.showcmd(p.Dir, "rm -f %s", strings.Join(allRemove, " "))
+	}
+
+	toRemove := map[string]bool{}
+	for _, name := range allRemove {
+		toRemove[name] = true
+	}
+	for _, dir := range dirs {
+		name := dir.Name()
+		if dir.IsDir() {
+			// TODO: Remove once Makefiles are forgotten.
+			if cleanDir[name] {
+				if buildN || buildX {
+					b.showcmd(p.Dir, "rm -r %s", name)
+					if buildN {
+						continue
+					}
+				}
+				if err := os.RemoveAll(filepath.Join(p.Dir, name)); err != nil {
+					errorf("go clean: %v", err)
+				}
+			}
+			continue
+		}
+
+		if buildN {
+			continue
+		}
+
+		if cleanFile[name] || cleanExt[filepath.Ext(name)] || toRemove[name] {
+			removeFile(filepath.Join(p.Dir, name))
+		}
+	}
+
+	if cleanI && p.target != "" {
+		if buildN || buildX {
+			b.showcmd("", "rm -f %s", p.target)
+		}
+		if !buildN {
+			removeFile(p.target)
+		}
+	}
+
+	if cleanR {
+		for _, p1 := range p.imports {
+			clean(p1)
+		}
+	}
+}
+
+// removeFile tries to remove file f, if error other than file doesn't exist
+// occurs, it will report the error.
+func removeFile(f string) {
+	err := os.Remove(f)
+	if err == nil || os.IsNotExist(err) {
+		return
+	}
+	// Windows does not allow deletion of a binary file while it is executing.
+	if toolIsWindows {
+		// Remove lingering ~ file from last attempt.
+		if _, err2 := os.Stat(f + "~"); err2 == nil {
+			os.Remove(f + "~")
+		}
+		// Try to move it out of the way. If the move fails,
+		// which is likely, we'll try again the
+		// next time we do an install of this binary.
+		if err2 := os.Rename(f, f+"~"); err2 == nil {
+			os.Remove(f + "~")
+			return
+		}
+	}
+	errorf("go clean: %v", err)
+}

libgo/go/cmd/go/context.go

@@ -0,0 +1,36 @@
+// Copyright 2014 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.
+
+package main
+
+import (
+	"go/build"
+)
+
+type Context struct {
+	GOARCH        string   `json:",omitempty"` // target architecture
+	GOOS          string   `json:",omitempty"` // target operating system
+	GOROOT        string   `json:",omitempty"` // Go root
+	GOPATH        string   `json:",omitempty"` // Go path
+	CgoEnabled    bool     `json:",omitempty"` // whether cgo can be used
+	UseAllFiles   bool     `json:",omitempty"` // use files regardless of +build lines, file names
+	Compiler      string   `json:",omitempty"` // compiler to assume when computing target paths
+	BuildTags     []string `json:",omitempty"` // build constraints to match in +build lines
+	ReleaseTags   []string `json:",omitempty"` // releases the current release is compatible with
+	InstallSuffix string   `json:",omitempty"` // suffix to use in the name of the install dir
+}
+
+func newContext(c *build.Context) *Context {
+	return &Context{
+		GOARCH:        c.GOARCH,
+		GOOS:          c.GOOS,
+		GOROOT:        c.GOROOT,
+		CgoEnabled:    c.CgoEnabled,
+		UseAllFiles:   c.UseAllFiles,
+		Compiler:      c.Compiler,
+		BuildTags:     c.BuildTags,
+		ReleaseTags:   c.ReleaseTags,
+		InstallSuffix: c.InstallSuffix,
+	}
+}

libgo/go/cmd/go/discovery.go

@@ -0,0 +1,83 @@
+// Copyright 2012 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.
+
+// +build !cmd_go_bootstrap
+
+// This code is compiled into the real 'go' binary, but it is not
+// compiled into the binary that is built during all.bash, so as
+// to avoid needing to build net (and thus use cgo) during the
+// bootstrap process.
+
+package main
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// charsetReader returns a reader for the given charset. Currently
+// it only supports UTF-8 and ASCII. Otherwise, it returns a meaningful
+// error which is printed by go get, so the user can find why the package
+// wasn't downloaded if the encoding is not supported. Note that, in
+// order to reduce potential errors, ASCII is treated as UTF-8 (i.e. characters
+// greater than 0x7f are not rejected).
+func charsetReader(charset string, input io.Reader) (io.Reader, error) {
+	switch strings.ToLower(charset) {
+	case "ascii":
+		return input, nil
+	default:
+		return nil, fmt.Errorf("can't decode XML document using charset %q", charset)
+	}
+}
+
+// parseMetaGoImports returns meta imports from the HTML in r.
+// Parsing ends at the end of the <head> section or the beginning of the <body>.
+func parseMetaGoImports(r io.Reader) (imports []metaImport, err error) {
+	d := xml.NewDecoder(r)
+	d.CharsetReader = charsetReader
+	d.Strict = false
+	var t xml.Token
+	for {
+		t, err = d.Token()
+		if err != nil {
+			if err == io.EOF {
+				err = nil
+			}
+			return
+		}
+		if e, ok := t.(xml.StartElement); ok && strings.EqualFold(e.Name.Local, "body") {
+			return
+		}
+		if e, ok := t.(xml.EndElement); ok && strings.EqualFold(e.Name.Local, "head") {
+			return
+		}
+		e, ok := t.(xml.StartElement)
+		if !ok || !strings.EqualFold(e.Name.Local, "meta") {
+			continue
+		}
+		if attrValue(e.Attr, "name") != "go-import" {
+			continue
+		}
+		if f := strings.Fields(attrValue(e.Attr, "content")); len(f) == 3 {
+			imports = append(imports, metaImport{
+				Prefix:   f[0],
+				VCS:      f[1],
+				RepoRoot: f[2],
+			})
+		}
+	}
+}
+
+// attrValue returns the attribute value for the case-insensitive key
+// `name', or the empty string if nothing is found.
+func attrValue(attrs []xml.Attr, name string) string {
+	for _, a := range attrs {
+		if strings.EqualFold(a.Name.Local, name) {
+			return a.Value
+		}
+	}
+	return ""
+}

libgo/go/cmd/go/doc.go

@@ -0,0 +1,990 @@
+// Copyright 2011 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.
+
+// DO NOT EDIT THIS FILE. GENERATED BY mkdoc.sh.
+// Edit the documentation in other files and rerun mkdoc.sh to generate this one.
+
+/*
+Go is a tool for managing Go source code.
+
+Usage:
+
+	go command [arguments]
+
+The commands are:
+
+    build       compile packages and dependencies
+    clean       remove object files
+    env         print Go environment information
+    fix         run go tool fix on packages
+    fmt         run gofmt on package sources
+    get         download and install packages and dependencies
+    install     compile and install packages and dependencies
+    list        list packages
+    run         compile and run Go program
+    test        test packages
+    tool        run specified go tool
+    version     print Go version
+    vet         run go tool vet on packages
+
+Use "go help [command]" for more information about a command.
+
+Additional help topics:
+
+    c           calling between Go and C
+    filetype    file types
+    gopath      GOPATH environment variable
+    importpath  import path syntax
+    packages    description of package lists
+    testflag    description of testing flags
+    testfunc    description of testing functions
+
+Use "go help [topic]" for more information about that topic.
+
+
+Compile packages and dependencies
+
+Usage:
+
+	go build [-o output] [-i] [build flags] [packages]
+
+Build compiles the packages named by the import paths,
+along with their dependencies, but it does not install the results.
+
+If the arguments are a list of .go files, build treats them as a list
+of source files specifying a single package.
+
+When the command line specifies a single main package,
+build writes the resulting executable to output.
+Otherwise build compiles the packages but discards the results,
+serving only as a check that the packages can be built.
+
+The -o flag specifies the output file name. If not specified, the
+output file name depends on the arguments and derives from the name
+of the package, such as p.a for package p, unless p is 'main'. If
+the package is main and file names are provided, the file name
+derives from the first file name mentioned, such as f1 for 'go build
+f1.go f2.go'; with no files provided ('go build'), the output file
+name is the base name of the containing directory.
+
+The -i flag installs the packages that are dependencies of the target.
+
+The build flags are shared by the build, clean, get, install, list, run,
+and test commands:
+
+	-a
+		force rebuilding of packages that are already up-to-date.
+	-n
+		print the commands but do not run them.
+	-p n
+		the number of builds that can be run in parallel.
+		The default is the number of CPUs available.
+	-race
+		enable data race detection.
+		Supported only on linux/amd64, darwin/amd64 and windows/amd64.
+	-v
+		print the names of packages as they are compiled.
+	-work
+		print the name of the temporary work directory and
+		do not delete it when exiting.
+	-x
+		print the commands.
+
+	-ccflags 'arg list'
+		arguments to pass on each 5c, 6c, or 8c compiler invocation.
+	-compiler name
+		name of compiler to use, as in runtime.Compiler (gccgo or gc).
+	-gccgoflags 'arg list'
+		arguments to pass on each gccgo compiler/linker invocation.
+	-gcflags 'arg list'
+		arguments to pass on each 5g, 6g, or 8g compiler invocation.
+	-installsuffix suffix
+		a suffix to use in the name of the package installation directory,
+		in order to keep output separate from default builds.
+		If using the -race flag, the install suffix is automatically set to race
+		or, if set explicitly, has _race appended to it.
+	-ldflags 'flag list'
+		arguments to pass on each 5l, 6l, or 8l linker invocation.
+	-tags 'tag list'
+		a list of build tags to consider satisfied during the build.
+		For more information about build tags, see the description of
+		build constraints in the documentation for the go/build package.
+
+The list flags accept a space-separated list of strings. To embed spaces
+in an element in the list, surround it with either single or double quotes.
+
+For more about specifying packages, see 'go help packages'.
+For more about where packages and binaries are installed,
+run 'go help gopath'.  For more about calling between Go and C/C++,
+run 'go help c'.
+
+See also: go install, go get, go clean.
+
+
+Remove object files
+
+Usage:
+
+	go clean [-i] [-r] [-n] [-x] [build flags] [packages]
+
+Clean removes object files from package source directories.
+The go command builds most objects in a temporary directory,
+so go clean is mainly concerned with object files left by other
+tools or by manual invocations of go build.
+
+Specifically, clean removes the following files from each of the
+source directories corresponding to the import paths:
+
+	_obj/            old object directory, left from Makefiles
+	_test/           old test directory, left from Makefiles
+	_testmain.go     old gotest file, left from Makefiles
+	test.out         old test log, left from Makefiles
+	build.out        old test log, left from Makefiles
+	*.[568ao]        object files, left from Makefiles
+
+	DIR(.exe)        from go build
+	DIR.test(.exe)   from go test -c
+	MAINFILE(.exe)   from go build MAINFILE.go
+	*.so             from SWIG
+
+In the list, DIR represents the final path element of the
+directory, and MAINFILE is the base name of any Go source
+file in the directory that is not included when building
+the package.
+
+The -i flag causes clean to remove the corresponding installed
+archive or binary (what 'go install' would create).
+
+The -n flag causes clean to print the remove commands it would execute,
+but not run them.
+
+The -r flag causes clean to be applied recursively to all the
+dependencies of the packages named by the import paths.
+
+The -x flag causes clean to print remove commands as it executes them.
+
+For more about build flags, see 'go help build'.
+
+For more about specifying packages, see 'go help packages'.
+
+
+Print Go environment information
+
+Usage:
+
+	go env [var ...]
+
+Env prints Go environment information.
+
+By default env prints information as a shell script
+(on Windows, a batch file).  If one or more variable
+names is given as arguments,  env prints the value of
+each named variable on its own line.
+
+
+Run go tool fix on packages
+
+Usage:
+
+	go fix [packages]
+
+Fix runs the Go fix command on the packages named by the import paths.
+
+For more about fix, see 'godoc fix'.
+For more about specifying packages, see 'go help packages'.
+
+To run fix with specific options, run 'go tool fix'.
+
+See also: go fmt, go vet.
+
+
+Run gofmt on package sources
+
+Usage:
+
+	go fmt [-n] [-x] [packages]
+
+Fmt runs the command 'gofmt -l -w' on the packages named
+by the import paths.  It prints the names of the files that are modified.
+
+For more about gofmt, see 'godoc gofmt'.
+For more about specifying packages, see 'go help packages'.
+
+The -n flag prints commands that would be executed.
+The -x flag prints commands as they are executed.
+
+To run gofmt with specific options, run gofmt itself.
+
+See also: go fix, go vet.
+
+
+Download and install packages and dependencies
+
+Usage:
+
+	go get [-d] [-fix] [-t] [-u] [build flags] [packages]
+
+Get downloads and installs the packages named by the import paths,
+along with their dependencies.
+
+The -d flag instructs get to stop after downloading the packages; that is,
+it instructs get not to install the packages.
+
+The -fix flag instructs get to run the fix tool on the downloaded packages
+before resolving dependencies or building the code.
+
+The -t flag instructs get to also download the packages required to build
+the tests for the specified packages.
+
+The -u flag instructs get to use the network to update the named packages
+and their dependencies.  By default, get uses the network to check out
+missing packages but does not use it to look for updates to existing packages.
+
+Get also accepts build flags to control the installation. See 'go help build'.
+
+When checking out or updating a package, get looks for a branch or tag
+that matches the locally installed version of Go. The most important
+rule is that if the local installation is running version "go1", get
+searches for a branch or tag named "go1". If no such version exists it
+retrieves the most recent version of the package.
+
+For more about specifying packages, see 'go help packages'.
+
+For more about how 'go get' finds source code to
+download, see 'go help importpath'.
+
+See also: go build, go install, go clean.
+
+
+Compile and install packages and dependencies
+
+Usage:
+
+	go install [build flags] [packages]
+
+Install compiles and installs the packages named by the import paths,
+along with their dependencies.
+
+For more about the build flags, see 'go help build'.
+For more about specifying packages, see 'go help packages'.
+
+See also: go build, go get, go clean.
+
+
+List packages
+
+Usage:
+
+	go list [-e] [-f format] [-json] [build flags] [packages]
+
+List lists the packages named by the import paths, one per line.
+
+The default output shows the package import path:
+
+    code.google.com/p/google-api-go-client/books/v1
+    code.google.com/p/goauth2/oauth
+    code.google.com/p/sqlite
+
+The -f flag specifies an alternate format for the list, using the
+syntax of package template.  The default output is equivalent to -f
+'{{.ImportPath}}'. The struct being passed to the template is:
+
+    type Package struct {
+        Dir        string // directory containing package sources
+        ImportPath string // import path of package in dir
+        Name       string // package name
+        Doc        string // package documentation string
+        Target     string // install path
+        Goroot     bool   // is this package in the Go root?
+        Standard   bool   // is this package part of the standard Go library?
+        Stale      bool   // would 'go install' do anything for this package?
+        Root       string // Go root or Go path dir containing this package
+
+        // Source files
+        GoFiles  []string       // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+        CgoFiles []string       // .go sources files that import "C"
+        IgnoredGoFiles []string // .go sources ignored due to build constraints
+        CFiles   []string       // .c source files
+        CXXFiles []string       // .cc, .cxx and .cpp source files
+        MFiles   []string       // .m source files
+        HFiles   []string       // .h, .hh, .hpp and .hxx source files
+        SFiles   []string       // .s source files
+        SwigFiles []string      // .swig files
+        SwigCXXFiles []string   // .swigcxx files
+        SysoFiles []string      // .syso object files to add to archive
+
+        // Cgo directives
+        CgoCFLAGS    []string // cgo: flags for C compiler
+        CgoCPPFLAGS  []string // cgo: flags for C preprocessor
+        CgoCXXFLAGS  []string // cgo: flags for C++ compiler
+        CgoLDFLAGS   []string // cgo: flags for linker
+        CgoPkgConfig []string // cgo: pkg-config names
+
+        // Dependency information
+        Imports []string // import paths used by this package
+        Deps    []string // all (recursively) imported dependencies
+
+        // Error information
+        Incomplete bool            // this package or a dependency has an error
+        Error      *PackageError   // error loading package
+        DepsErrors []*PackageError // errors loading dependencies
+
+        TestGoFiles  []string // _test.go files in package
+        TestImports  []string // imports from TestGoFiles
+        XTestGoFiles []string // _test.go files outside package
+        XTestImports []string // imports from XTestGoFiles
+    }
+
+The template function "join" calls strings.Join.
+
+The template function "context" returns the build context, defined as:
+
+	type Context struct {
+		GOARCH        string   // target architecture
+		GOOS          string   // target operating system
+		GOROOT        string   // Go root
+		GOPATH        string   // Go path
+		CgoEnabled    bool     // whether cgo can be used
+		UseAllFiles   bool     // use files regardless of +build lines, file names
+		Compiler      string   // compiler to assume when computing target paths
+		BuildTags     []string // build constraints to match in +build lines
+		ReleaseTags   []string // releases the current release is compatible with
+		InstallSuffix string   // suffix to use in the name of the install dir
+	}
+
+For more information about the meaning of these fields see the documentation
+for the go/build package's Context type.
+
+The -json flag causes the package data to be printed in JSON format
+instead of using the template format.
+
+The -e flag changes the handling of erroneous packages, those that
+cannot be found or are malformed.  By default, the list command
+prints an error to standard error for each erroneous package and
+omits the packages from consideration during the usual printing.
+With the -e flag, the list command never prints errors to standard
+error and instead processes the erroneous packages with the usual
+printing.  Erroneous packages will have a non-empty ImportPath and
+a non-nil Error field; other information may or may not be missing
+(zeroed).
+
+For more about build flags, see 'go help build'.
+
+For more about specifying packages, see 'go help packages'.
+
+
+Compile and run Go program
+
+Usage:
+
+	go run [build flags] [-exec xprog] gofiles... [arguments...]
+
+Run compiles and runs the main package comprising the named Go source files.
+A Go source file is defined to be a file ending in a literal ".go" suffix.
+
+By default, 'go run' runs the compiled binary directly: 'a.out arguments...'.
+If the -exec flag is given, 'go run' invokes the binary using xprog: 'xprog a.out arguments...'.
+If the -exec flag is not given, GOOS or GOARCH is different from the system
+default, and a program named go_$GOOS_$GOARCH_exec can be found
+on the current search path, 'go run' invokes the binary using that program,
+for example 'go_nacl_386_exec a.out arguments...'. This allows execution of
+cross-compiled programs when a simulator or other execution method is
+available.
+
+For more about build flags, see 'go help build'.
+
+See also: go build.
+
+
+Test packages
+
+Usage:
+
+	go test [-c] [-i] [build and test flags] [packages] [flags for test binary]
+
+'Go test' automates testing the packages named by the import paths.
+It prints a summary of the test results in the format:
+
+	ok   archive/tar   0.011s
+	FAIL archive/zip   0.022s
+	ok   compress/gzip 0.033s
+	...
+
+followed by detailed output for each failed package.
+
+'Go test' recompiles each package along with any files with names matching
+the file pattern "*_test.go".
+Files whose names begin with "_" (including "_test.go") or "." are ignored.
+These additional files can contain test functions, benchmark functions, and
+example functions.  See 'go help testfunc' for more.
+Each listed package causes the execution of a separate test binary.
+
+Test files that declare a package with the suffix "_test" will be compiled as a
+separate package, and then linked and run with the main test binary.
+
+By default, go test needs no arguments.  It compiles and tests the package
+with source in the current directory, including tests, and runs the tests.
+
+The package is built in a temporary directory so it does not interfere with the
+non-test installation.
+
+In addition to the build flags, the flags handled by 'go test' itself are:
+
+	-c  Compile the test binary to pkg.test but do not run it.
+	    (Where pkg is the last element of the package's import path.)
+
+	-i
+	    Install packages that are dependencies of the test.
+	    Do not run the test.
+
+	-exec xprog
+	    Run the test binary using xprog. The behavior is the same as
+	    in 'go run'. See 'go help run' for details.
+
+The test binary also accepts flags that control execution of the test; these
+flags are also accessible by 'go test'.  See 'go help testflag' for details.
+
+If the test binary needs any other flags, they should be presented after the
+package names. The go tool treats as a flag the first argument that begins with
+a minus sign that it does not recognize itself; that argument and all subsequent
+arguments are passed as arguments to the test binary.
+
+For more about build flags, see 'go help build'.
+For more about specifying packages, see 'go help packages'.
+
+See also: go build, go vet.
+
+
+Run specified go tool
+
+Usage:
+
+	go tool [-n] command [args...]
+
+Tool runs the go tool command identified by the arguments.
+With no arguments it prints the list of known tools.
+
+The -n flag causes tool to print the command that would be
+executed but not execute it.
+
+For more about each tool command, see 'go tool command -h'.
+
+
+Print Go version
+
+Usage:
+
+	go version
+
+Version prints the Go version, as reported by runtime.Version.
+
+
+Run go tool vet on packages
+
+Usage:
+
+	go vet [-n] [-x] [packages]
+
+Vet runs the Go vet command on the packages named by the import paths.
+
+For more about vet, see 'godoc code.google.com/p/go.tools/cmd/vet'.
+For more about specifying packages, see 'go help packages'.
+
+To run the vet tool with specific options, run 'go tool vet'.
+
+The -n flag prints commands that would be executed.
+The -x flag prints commands as they are executed.
+
+See also: go fmt, go fix.
+
+
+Calling between Go and C
+
+There are two different ways to call between Go and C/C++ code.
+
+The first is the cgo tool, which is part of the Go distribution.  For
+information on how to use it see the cgo documentation (godoc cmd/cgo).
+
+The second is the SWIG program, which is a general tool for
+interfacing between languages.  For information on SWIG see
+http://swig.org/.  When running go build, any file with a .swig
+extension will be passed to SWIG.  Any file with a .swigcxx extension
+will be passed to SWIG with the -c++ option.
+
+When either cgo or SWIG is used, go build will pass any .c, .m, .s,
+or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++
+compiler.  The CC or CXX environment variables may be set to determine
+the C or C++ compiler, respectively, to use.
+
+
+File types
+
+The go command examines the contents of a restricted set of files
+in each directory. It identifies which files to examine based on
+the extension of the file name. These extensions are:
+
+	.go
+		Go source files.
+	.c, .h
+		C source files.
+		If the package uses cgo, these will be compiled with the
+		OS-native compiler (typically gcc); otherwise they will be
+		compiled with the Go-specific support compiler,
+		5c, 6c, or 8c, etc. as appropriate.
+	.cc, .cpp, .cxx, .hh, .hpp, .hxx
+		C++ source files. Only useful with cgo or SWIG, and always
+		compiled with the OS-native compiler.
+	.m
+		Objective-C source files. Only useful with cgo, and always
+		compiled with the OS-native compiler.
+	.s, .S
+		Assembler source files.
+		If the package uses cgo, these will be assembled with the
+		OS-native assembler (typically gcc (sic)); otherwise they
+		will be assembled with the Go-specific support assembler,
+		5a, 6a, or 8a, etc., as appropriate.
+	.swig, .swigcxx
+		SWIG definition files.
+	.syso
+		System object files.
+
+Files of each of these types except .syso may contain build
+constraints, but the go command stops scanning for build constraints
+at the first item in the file that is not a blank line or //-style
+line comment.
+
+
+GOPATH environment variable
+
+The Go path is used to resolve import statements.
+It is implemented by and documented in the go/build package.
+
+The GOPATH environment variable lists places to look for Go code.
+On Unix, the value is a colon-separated string.
+On Windows, the value is a semicolon-separated string.
+On Plan 9, the value is a list.
+
+GOPATH must be set to get, build and install packages outside the
+standard Go tree.
+
+Each directory listed in GOPATH must have a prescribed structure:
+
+The src/ directory holds source code.  The path below 'src'
+determines the import path or executable name.
+
+The pkg/ directory holds installed package objects.
+As in the Go tree, each target operating system and
+architecture pair has its own subdirectory of pkg
+(pkg/GOOS_GOARCH).
+
+If DIR is a directory listed in the GOPATH, a package with
+source in DIR/src/foo/bar can be imported as "foo/bar" and
+has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a".
+
+The bin/ directory holds compiled commands.
+Each command is named for its source directory, but only
+the final element, not the entire path.  That is, the
+command with source in DIR/src/foo/quux is installed into
+DIR/bin/quux, not DIR/bin/foo/quux.  The foo/ is stripped
+so that you can add DIR/bin to your PATH to get at the
+installed commands.  If the GOBIN environment variable is
+set, commands are installed to the directory it names instead
+of DIR/bin.
+
+Here's an example directory layout:
+
+    GOPATH=/home/user/gocode
+
+    /home/user/gocode/
+        src/
+            foo/
+                bar/               (go code in package bar)
+                    x.go
+                quux/              (go code in package main)
+                    y.go
+        bin/
+            quux                   (installed command)
+        pkg/
+            linux_amd64/
+                foo/
+                    bar.a          (installed package object)
+
+Go searches each directory listed in GOPATH to find source code,
+but new packages are always downloaded into the first directory
+in the list.
+
+
+Import path syntax
+
+An import path (see 'go help packages') denotes a package
+stored in the local file system.  In general, an import path denotes
+either a standard package (such as "unicode/utf8") or a package
+found in one of the work spaces (see 'go help gopath').
+
+Relative import paths
+
+An import path beginning with ./ or ../ is called a relative path.
+The toolchain supports relative import paths as a shortcut in two ways.
+
+First, a relative path can be used as a shorthand on the command line.
+If you are working in the directory containing the code imported as
+"unicode" and want to run the tests for "unicode/utf8", you can type
+"go test ./utf8" instead of needing to specify the full path.
+Similarly, in the reverse situation, "go test .." will test "unicode" from
+the "unicode/utf8" directory. Relative patterns are also allowed, like
+"go test ./..." to test all subdirectories. See 'go help packages' for details
+on the pattern syntax.
+
+Second, if you are compiling a Go program not in a work space,
+you can use a relative path in an import statement in that program
+to refer to nearby code also not in a work space.
+This makes it easy to experiment with small multipackage programs
+outside of the usual work spaces, but such programs cannot be
+installed with "go install" (there is no work space in which to install them),
+so they are rebuilt from scratch each time they are built.
+To avoid ambiguity, Go programs cannot use relative import paths
+within a work space.
+
+Remote import paths
+
+Certain import paths also
+describe how to obtain the source code for the package using
+a revision control system.
+
+A few common code hosting sites have special syntax:
+
+	Bitbucket (Git, Mercurial)
+
+		import "bitbucket.org/user/project"
+		import "bitbucket.org/user/project/sub/directory"
+
+	GitHub (Git)
+
+		import "github.com/user/project"
+		import "github.com/user/project/sub/directory"
+
+	Google Code Project Hosting (Git, Mercurial, Subversion)
+
+		import "code.google.com/p/project"
+		import "code.google.com/p/project/sub/directory"
+
+		import "code.google.com/p/project.subrepository"
+		import "code.google.com/p/project.subrepository/sub/directory"
+
+	Launchpad (Bazaar)
+
+		import "launchpad.net/project"
+		import "launchpad.net/project/series"
+		import "launchpad.net/project/series/sub/directory"
+
+		import "launchpad.net/~user/project/branch"
+		import "launchpad.net/~user/project/branch/sub/directory"
+
+For code hosted on other servers, import paths may either be qualified
+with the version control type, or the go tool can dynamically fetch
+the import path over https/http and discover where the code resides
+from a <meta> tag in the HTML.
+
+To declare the code location, an import path of the form
+
+	repository.vcs/path
+
+specifies the given repository, with or without the .vcs suffix,
+using the named version control system, and then the path inside
+that repository.  The supported version control systems are:
+
+	Bazaar      .bzr
+	Git         .git
+	Mercurial   .hg
+	Subversion  .svn
+
+For example,
+
+	import "example.org/user/foo.hg"
+
+denotes the root directory of the Mercurial repository at
+example.org/user/foo or foo.hg, and
+
+	import "example.org/repo.git/foo/bar"
+
+denotes the foo/bar directory of the Git repository at
+example.org/repo or repo.git.
+
+When a version control system supports multiple protocols,
+each is tried in turn when downloading.  For example, a Git
+download tries git://, then https://, then http://.
+
+If the import path is not a known code hosting site and also lacks a
+version control qualifier, the go tool attempts to fetch the import
+over https/http and looks for a <meta> tag in the document's HTML
+<head>.
+
+The meta tag has the form:
+
+	<meta name="go-import" content="import-prefix vcs repo-root">
+
+The import-prefix is the import path corresponding to the repository
+root. It must be a prefix or an exact match of the package being
+fetched with "go get". If it's not an exact match, another http
+request is made at the prefix to verify the <meta> tags match.
+
+The vcs is one of "git", "hg", "svn", etc,
+
+The repo-root is the root of the version control system
+containing a scheme and not containing a .vcs qualifier.
+
+For example,
+
+	import "example.org/pkg/foo"
+
+will result in the following request(s):
+
+	https://example.org/pkg/foo?go-get=1 (preferred)
+	http://example.org/pkg/foo?go-get=1  (fallback)
+
+If that page contains the meta tag
+
+	<meta name="go-import" content="example.org git https://code.org/r/p/exproj">
+
+the go tool will verify that https://example.org/?go-get=1 contains the
+same meta tag and then git clone https://code.org/r/p/exproj into
+GOPATH/src/example.org.
+
+New downloaded packages are written to the first directory
+listed in the GOPATH environment variable (see 'go help gopath').
+
+The go command attempts to download the version of the
+package appropriate for the Go release being used.
+Run 'go help install' for more.
+
+
+Description of package lists
+
+Many commands apply to a set of packages:
+
+	go action [packages]
+
+Usually, [packages] is a list of import paths.
+
+An import path that is a rooted path or that begins with
+a . or .. element is interpreted as a file system path and
+denotes the package in that directory.
+
+Otherwise, the import path P denotes the package found in
+the directory DIR/src/P for some DIR listed in the GOPATH
+environment variable (see 'go help gopath').
+
+If no import paths are given, the action applies to the
+package in the current directory.
+
+There are three reserved names for paths that should not be used
+for packages to be built with the go tool:
+
+- "main" denotes the top-level package in a stand-alone executable.
+
+- "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.
+
+- "std" is like all but expands to just the packages in the standard
+Go library.
+
+An import path is a pattern if it includes one or more "..." wildcards,
+each of which can match any string, including the empty string and
+strings containing slashes.  Such a pattern expands to all package
+directories found in the GOPATH trees with names matching the
+patterns.  As a special case, x/... matches x as well as x's subdirectories.
+For example, net/... expands to net and packages in its subdirectories.
+
+An import path can also name a package to be downloaded from
+a remote repository.  Run 'go help importpath' for details.
+
+Every package in a program must have a unique import path.
+By convention, this is arranged by starting each path with a
+unique prefix that belongs to you.  For example, paths used
+internally at Google all begin with 'google', and paths
+denoting remote repositories begin with the path to the code,
+such as 'code.google.com/p/project'.
+
+As a special case, if the package list is a list of .go files from a
+single directory, the command is applied to a single synthesized
+package made up of exactly those files, ignoring any build constraints
+in those files and ignoring any other files in the directory.
+
+File names that begin with "." or "_" are ignored by the go tool.
+
+
+Description of testing flags
+
+The 'go test' command takes both flags that apply to 'go test' itself
+and flags that apply to the resulting test binary.
+
+Several of the flags control profiling and write an execution profile
+suitable for "go tool pprof"; run "go tool pprof help" for more
+information.  The --alloc_space, --alloc_objects, and --show_bytes
+options of pprof control how the information is presented.
+
+The following flags are recognized by the 'go test' command and
+control the execution of any test:
+
+	-bench regexp
+	    Run benchmarks matching the regular expression.
+	    By default, no benchmarks run. To run all benchmarks,
+	    use '-bench .' or '-bench=.'.
+
+	-benchmem
+	    Print memory allocation statistics for benchmarks.
+
+	-benchtime t
+	    Run enough iterations of each benchmark to take t, specified
+	    as a time.Duration (for example, -benchtime 1h30s).
+	    The default is 1 second (1s).
+
+	-blockprofile block.out
+	    Write a goroutine blocking profile to the specified file
+	    when all tests are complete.
+
+	-blockprofilerate n
+	    Control the detail provided in goroutine blocking profiles by
+	    calling runtime.SetBlockProfileRate with n.
+	    See 'godoc runtime SetBlockProfileRate'.
+	    The profiler aims to sample, on average, one blocking event every
+	    n nanoseconds the program spends blocked.  By default,
+	    if -test.blockprofile is set without this flag, all blocking events
+	    are recorded, equivalent to -test.blockprofilerate=1.
+
+	-cover
+	    Enable coverage analysis.
+
+	-covermode set,count,atomic
+	    Set the mode for coverage analysis for the package[s]
+	    being tested. The default is "set" unless -race is enabled,
+	    in which case it is "atomic".
+	    The values:
+		set: bool: does this statement run?
+		count: int: how many times does this statement run?
+		atomic: int: count, but correct in multithreaded tests;
+			significantly more expensive.
+	    Sets -cover.
+
+	-coverpkg pkg1,pkg2,pkg3
+	    Apply coverage analysis in each test to the given list of packages.
+	    The default is for each test to analyze only the package being tested.
+	    Packages are specified as import paths.
+	    Sets -cover.
+
+	-coverprofile cover.out
+	    Write a coverage profile to the specified file after all tests
+	    have passed.
+	    Sets -cover.
+
+	-cpu 1,2,4
+	    Specify a list of GOMAXPROCS values for which the tests or
+	    benchmarks should be executed.  The default is the current value
+	    of GOMAXPROCS.
+
+	-cpuprofile cpu.out
+	    Write a CPU profile to the specified file before exiting.
+
+	-memprofile mem.out
+	    Write a memory profile to the specified file after all tests
+	    have passed.
+
+	-memprofilerate n
+	    Enable more precise (and expensive) memory profiles by setting
+	    runtime.MemProfileRate.  See 'godoc runtime MemProfileRate'.
+	    To profile all memory allocations, use -test.memprofilerate=1
+	    and pass --alloc_space flag to the pprof tool.
+
+	-outputdir directory
+	    Place output files from profiling in the specified directory,
+	    by default the directory in which "go test" is running.
+
+	-parallel n
+	    Allow parallel execution of test functions that call t.Parallel.
+	    The value of this flag is the maximum number of tests to run
+	    simultaneously; by default, it is set to the value of GOMAXPROCS.
+
+	-run regexp
+	    Run only those tests and examples matching the regular
+	    expression.
+
+	-short
+	    Tell long-running tests to shorten their run time.
+	    It is off by default but set during all.bash so that installing
+	    the Go tree can run a sanity check but not spend time running
+	    exhaustive tests.
+
+	-timeout t
+	    If a test runs longer than t, panic.
+
+	-v
+	    Verbose output: log all tests as they are run. Also print all
+	    text from Log and Logf calls even if the test succeeds.
+
+The test binary, called pkg.test where pkg is the name of the
+directory containing the package sources, can be invoked directly
+after building it with 'go test -c'. When invoking the test binary
+directly, each of the standard flag names must be prefixed with 'test.',
+as in -test.run=TestMyFunc or -test.v.
+
+When running 'go test', flags not listed above are passed through
+unaltered. For instance, the command
+
+	go test -x -v -cpuprofile=prof.out -dir=testdata -update
+
+will compile the test binary and then run it as
+
+	pkg.test -test.v -test.cpuprofile=prof.out -dir=testdata -update
+
+The test flags that generate profiles (other than for coverage) also
+leave the test binary in pkg.test for use when analyzing the profiles.
+
+Flags not recognized by 'go test' must be placed after any specified packages.
+
+
+Description of testing functions
+
+The 'go test' command expects to find test, benchmark, and example functions
+in the "*_test.go" files corresponding to the package under test.
+
+A test function is one named TestXXX (where XXX is any alphanumeric string
+not starting with a lower case letter) and should have the signature,
+
+	func TestXXX(t *testing.T) { ... }
+
+A benchmark function is one named BenchmarkXXX and should have the signature,
+
+	func BenchmarkXXX(b *testing.B) { ... }
+
+An example function is similar to a test function but, instead of using
+*testing.T to report success or failure, prints output to os.Stdout.
+That output is compared against the function's "Output:" comment, which
+must be the last comment in the function body (see example below). An
+example with no such comment, or with no text after "Output:" is compiled
+but not executed.
+
+Godoc displays the body of ExampleXXX to demonstrate the use
+of the function, constant, or variable XXX.  An example of a method M with
+receiver type T or *T is named ExampleT_M.  There may be multiple examples
+for a given function, constant, or variable, distinguished by a trailing _xxx,
+where xxx is a suffix not beginning with an upper case letter.
+
+Here is an example of an example:
+
+	func ExamplePrintln() {
+		Println("The output of\nthis example.")
+		// Output: The output of
+		// this example.
+	}
+
+The entire test file is presented as the example when it contains a single
+example function, at least one other function, type, variable, or constant
+declaration, and no test or benchmark functions.
+
+See the documentation of the testing package for more information.
+
+
+*/
+package main

libgo/go/cmd/go/env.go

@@ -0,0 +1,112 @@
+// Copyright 2012 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.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"strings"
+)
+
+var cmdEnv = &Command{
+	Run:       runEnv,
+	UsageLine: "env [var ...]",
+	Short:     "print Go environment information",
+	Long: `
+Env prints Go environment information.
+
+By default env prints information as a shell script
+(on Windows, a batch file).  If one or more variable
+names is given as arguments,  env prints the value of
+each named variable on its own line.
+	`,
+}
+
+type envVar struct {
+	name, value string
+}
+
+func mkEnv() []envVar {
+	var b builder
+	b.init()
+
+	env := []envVar{
+		{"GOARCH", goarch},
+		{"GOBIN", gobin},
+		{"GOCHAR", archChar},
+		{"GOEXE", exeSuffix},
+		{"GOHOSTARCH", runtime.GOARCH},
+		{"GOHOSTOS", runtime.GOOS},
+		{"GOOS", goos},
+		{"GOPATH", os.Getenv("GOPATH")},
+		{"GORACE", os.Getenv("GORACE")},
+		{"GOROOT", goroot},
+		{"GOTOOLDIR", toolDir},
+
+		// disable escape codes in clang errors
+		{"TERM", "dumb"},
+	}
+
+	if goos != "plan9" {
+		cmd := b.gccCmd(".")
+		env = append(env, envVar{"CC", cmd[0]})
+		env = append(env, envVar{"GOGCCFLAGS", strings.Join(cmd[3:], " ")})
+		cmd = b.gxxCmd(".")
+		env = append(env, envVar{"CXX", cmd[0]})
+	}
+
+	if buildContext.CgoEnabled {
+		env = append(env, envVar{"CGO_ENABLED", "1"})
+	} else {
+		env = append(env, envVar{"CGO_ENABLED", "0"})
+	}
+
+	return env
+}
+
+func findEnv(env []envVar, name string) string {
+	for _, e := range env {
+		if e.name == name {
+			return e.value
+		}
+	}
+	return ""
+}
+
+func runEnv(cmd *Command, args []string) {
+	env := mkEnv()
+	if len(args) > 0 {
+		for _, name := range args {
+			fmt.Printf("%s\n", findEnv(env, name))
+		}
+		return
+	}
+
+	for _, e := range env {
+		if e.name != "TERM" {
+			switch runtime.GOOS {
+			default:
+				fmt.Printf("%s=\"%s\"\n", e.name, e.value)
+			case "plan9":
+				if strings.IndexByte(e.value, '\x00') < 0 {
+					fmt.Printf("%s='%s'\n", e.name, strings.Replace(e.value, "'", "''", -1))
+				} else {
+					v := strings.Split(e.value, "\x00")
+					fmt.Printf("%s=(", e.name)
+					for x, s := range v {
+						if x > 0 {
+							fmt.Printf(" ")
+						}
+						fmt.Printf("%s", s)
+					}
+					fmt.Printf(")\n")
+				}
+			case "windows":
+				fmt.Printf("set %s=%s\n", e.name, e.value)
+			}
+		}
+	}
+}

libgo/go/cmd/go/fix.go

@@ -0,0 +1,30 @@
+// Copyright 2011 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.
+
+package main
+
+var cmdFix = &Command{
+	Run:       runFix,
+	UsageLine: "fix [packages]",
+	Short:     "run go tool fix on packages",
+	Long: `
+Fix runs the Go fix command on the packages named by the import paths.
+
+For more about fix, see 'godoc fix'.
+For more about specifying packages, see 'go help packages'.
+
+To run fix with specific options, run 'go tool fix'.
+
+See also: go fmt, go vet.
+	`,
+}
+
+func runFix(cmd *Command, args []string) {
+	for _, pkg := range packages(args) {
+		// Use pkg.gofiles instead of pkg.Dir so that
+		// the command only applies to this package,
+		// not to packages in subdirectories.
+		run(stringList(tool("fix"), relPaths(pkg.allgofiles)))
+	}
+}

libgo/go/cmd/go/fmt.go

@@ -0,0 +1,38 @@
+// Copyright 2011 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.
+
+package main
+
+func init() {
+	addBuildFlagsNX(cmdFmt)
+}
+
+var cmdFmt = &Command{
+	Run:       runFmt,
+	UsageLine: "fmt [-n] [-x] [packages]",
+	Short:     "run gofmt on package sources",
+	Long: `
+Fmt runs the command 'gofmt -l -w' on the packages named
+by the import paths.  It prints the names of the files that are modified.
+
+For more about gofmt, see 'godoc gofmt'.
+For more about specifying packages, see 'go help packages'.
+
+The -n flag prints commands that would be executed.
+The -x flag prints commands as they are executed.
+
+To run gofmt with specific options, run gofmt itself.
+
+See also: go fix, go vet.
+	`,
+}
+
+func runFmt(cmd *Command, args []string) {
+	for _, pkg := range packages(args) {
+		// Use pkg.gofiles instead of pkg.Dir so that
+		// the command only applies to this package,
+		// not to packages in subdirectories.
+		run(stringList("gofmt", "-l", "-w", relPaths(pkg.allgofiles)))
+	}
+}

libgo/go/cmd/go/get.go

@@ -0,0 +1,429 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"fmt"
+	"go/build"
+	"os"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+)
+
+var cmdGet = &Command{
+	UsageLine: "get [-d] [-fix] [-t] [-u] [build flags] [packages]",
+	Short:     "download and install packages and dependencies",
+	Long: `
+Get downloads and installs the packages named by the import paths,
+along with their dependencies.
+
+The -d flag instructs get to stop after downloading the packages; that is,
+it instructs get not to install the packages.
+
+The -fix flag instructs get to run the fix tool on the downloaded packages
+before resolving dependencies or building the code.
+
+The -t flag instructs get to also download the packages required to build
+the tests for the specified packages.
+
+The -u flag instructs get to use the network to update the named packages
+and their dependencies.  By default, get uses the network to check out
+missing packages but does not use it to look for updates to existing packages.
+
+Get also accepts build flags to control the installation. See 'go help build'.
+
+When checking out or updating a package, get looks for a branch or tag
+that matches the locally installed version of Go. The most important
+rule is that if the local installation is running version "go1", get
+searches for a branch or tag named "go1". If no such version exists it
+retrieves the most recent version of the package.
+
+For more about specifying packages, see 'go help packages'.
+
+For more about how 'go get' finds source code to
+download, see 'go help importpath'.
+
+See also: go build, go install, go clean.
+	`,
+}
+
+var getD = cmdGet.Flag.Bool("d", false, "")
+var getT = cmdGet.Flag.Bool("t", false, "")
+var getU = cmdGet.Flag.Bool("u", false, "")
+var getFix = cmdGet.Flag.Bool("fix", false, "")
+
+func init() {
+	addBuildFlags(cmdGet)
+	cmdGet.Run = runGet // break init loop
+}
+
+func runGet(cmd *Command, args []string) {
+	// Phase 1.  Download/update.
+	var stk importStack
+	for _, arg := range downloadPaths(args) {
+		download(arg, &stk, *getT)
+	}
+	exitIfErrors()
+
+	// Phase 2. Rescan packages and re-evaluate args list.
+
+	// Code we downloaded and all code that depends on it
+	// needs to be evicted from the package cache so that
+	// the information will be recomputed.  Instead of keeping
+	// track of the reverse dependency information, evict
+	// everything.
+	for name := range packageCache {
+		delete(packageCache, name)
+	}
+
+	args = importPaths(args)
+
+	// Phase 3.  Install.
+	if *getD {
+		// Download only.
+		// Check delayed until now so that importPaths
+		// has a chance to print errors.
+		return
+	}
+
+	runInstall(cmd, args)
+}
+
+// downloadPaths prepares the list of paths to pass to download.
+// It expands ... patterns that can be expanded.  If there is no match
+// for a particular pattern, downloadPaths leaves it in the result list,
+// in the hope that we can figure out the repository from the
+// initial ...-free prefix.
+func downloadPaths(args []string) []string {
+	args = importPathsNoDotExpansion(args)
+	var out []string
+	for _, a := range args {
+		if strings.Contains(a, "...") {
+			var expand []string
+			// Use matchPackagesInFS to avoid printing
+			// warnings.  They will be printed by the
+			// eventual call to importPaths instead.
+			if build.IsLocalImport(a) {
+				expand = matchPackagesInFS(a)
+			} else {
+				expand = matchPackages(a)
+			}
+			if len(expand) > 0 {
+				out = append(out, expand...)
+				continue
+			}
+		}
+		out = append(out, a)
+	}
+	return out
+}
+
+// downloadCache records the import paths we have already
+// considered during the download, to avoid duplicate work when
+// there is more than one dependency sequence leading to
+// a particular package.
+var downloadCache = map[string]bool{}
+
+// downloadRootCache records the version control repository
+// root directories we have already considered during the download.
+// For example, all the packages in the code.google.com/p/codesearch repo
+// share the same root (the directory for that path), and we only need
+// to run the hg commands to consider each repository once.
+var downloadRootCache = map[string]bool{}
+
+// download runs the download half of the get command
+// for the package named by the argument.
+func download(arg string, stk *importStack, getTestDeps bool) {
+	p := loadPackage(arg, stk)
+	if p.Error != nil && p.Error.hard {
+		errorf("%s", p.Error)
+		return
+	}
+
+	// There's nothing to do if this is a package in the standard library.
+	if p.Standard {
+		return
+	}
+
+	// Only process each package once.
+	if downloadCache[arg] {
+		return
+	}
+	downloadCache[arg] = true
+
+	pkgs := []*Package{p}
+	wildcardOkay := len(*stk) == 0
+	isWildcard := false
+
+	// Download if the package is missing, or update if we're using -u.
+	if p.Dir == "" || *getU {
+		// The actual download.
+		stk.push(p.ImportPath)
+		err := downloadPackage(p)
+		if err != nil {
+			errorf("%s", &PackageError{ImportStack: stk.copy(), Err: err.Error()})
+			stk.pop()
+			return
+		}
+
+		args := []string{arg}
+		// If the argument has a wildcard in it, re-evaluate the wildcard.
+		// We delay this until after reloadPackage so that the old entry
+		// for p has been replaced in the package cache.
+		if wildcardOkay && strings.Contains(arg, "...") {
+			if build.IsLocalImport(arg) {
+				args = matchPackagesInFS(arg)
+			} else {
+				args = matchPackages(arg)
+			}
+			isWildcard = true
+		}
+
+		// Clear all relevant package cache entries before
+		// doing any new loads.
+		for _, arg := range args {
+			p := packageCache[arg]
+			if p != nil {
+				delete(packageCache, p.Dir)
+				delete(packageCache, p.ImportPath)
+			}
+		}
+
+		pkgs = pkgs[:0]
+		for _, arg := range args {
+			stk.push(arg)
+			p := loadPackage(arg, stk)
+			stk.pop()
+			if p.Error != nil {
+				errorf("%s", p.Error)
+				continue
+			}
+			pkgs = append(pkgs, p)
+		}
+	}
+
+	// Process package, which might now be multiple packages
+	// due to wildcard expansion.
+	for _, p := range pkgs {
+		if *getFix {
+			run(stringList(tool("fix"), relPaths(p.allgofiles)))
+
+			// The imports might have changed, so reload again.
+			p = reloadPackage(arg, stk)
+			if p.Error != nil {
+				errorf("%s", p.Error)
+				return
+			}
+		}
+
+		if isWildcard {
+			// Report both the real package and the
+			// wildcard in any error message.
+			stk.push(p.ImportPath)
+		}
+
+		// Process dependencies, now that we know what they are.
+		for _, dep := range p.deps {
+			// Don't get test dependencies recursively.
+			download(dep.ImportPath, stk, false)
+		}
+		if getTestDeps {
+			// Process test dependencies when -t is specified.
+			// (Don't get test dependencies for test dependencies.)
+			for _, path := range p.TestImports {
+				download(path, stk, false)
+			}
+			for _, path := range p.XTestImports {
+				download(path, stk, false)
+			}
+		}
+
+		if isWildcard {
+			stk.pop()
+		}
+	}
+}
+
+// downloadPackage runs the create or download command
+// to make the first copy of or update a copy of the given package.
+func downloadPackage(p *Package) error {
+	var (
+		vcs            *vcsCmd
+		repo, rootPath string
+		err            error
+	)
+	if p.build.SrcRoot != "" {
+		// Directory exists.  Look for checkout along path to src.
+		vcs, rootPath, err = vcsForDir(p)
+		if err != nil {
+			return err
+		}
+		repo = "<local>" // should be unused; make distinctive
+	} else {
+		// Analyze the import path to determine the version control system,
+		// repository, and the import path for the root of the repository.
+		rr, err := repoRootForImportPath(p.ImportPath)
+		if err != nil {
+			return err
+		}
+		vcs, repo, rootPath = rr.vcs, rr.repo, rr.root
+	}
+
+	if p.build.SrcRoot == "" {
+		// Package not found.  Put in first directory of $GOPATH.
+		list := filepath.SplitList(buildContext.GOPATH)
+		if len(list) == 0 {
+			return fmt.Errorf("cannot download, $GOPATH not set. For more details see: go help gopath")
+		}
+		// Guard against people setting GOPATH=$GOROOT.
+		if list[0] == goroot {
+			return fmt.Errorf("cannot download, $GOPATH must not be set to $GOROOT. For more details see: go help gopath")
+		}
+		p.build.SrcRoot = filepath.Join(list[0], "src")
+		p.build.PkgRoot = filepath.Join(list[0], "pkg")
+	}
+	root := filepath.Join(p.build.SrcRoot, rootPath)
+	// If we've considered this repository already, don't do it again.
+	if downloadRootCache[root] {
+		return nil
+	}
+	downloadRootCache[root] = true
+
+	if buildV {
+		fmt.Fprintf(os.Stderr, "%s (download)\n", rootPath)
+	}
+
+	// Check that this is an appropriate place for the repo to be checked out.
+	// The target directory must either not exist or have a repo checked out already.
+	meta := filepath.Join(root, "."+vcs.cmd)
+	st, err := os.Stat(meta)
+	if err == nil && !st.IsDir() {
+		return fmt.Errorf("%s exists but is not a directory", meta)
+	}
+	if err != nil {
+		// Metadata directory does not exist.  Prepare to checkout new copy.
+		// Some version control tools require the target directory not to exist.
+		// We require that too, just to avoid stepping on existing work.
+		if _, err := os.Stat(root); err == nil {
+			return fmt.Errorf("%s exists but %s does not - stale checkout?", root, meta)
+		}
+		// Some version control tools require the parent of the target to exist.
+		parent, _ := filepath.Split(root)
+		if err = os.MkdirAll(parent, 0777); err != nil {
+			return err
+		}
+		if err = vcs.create(root, repo); err != nil {
+			return err
+		}
+	} else {
+		// Metadata directory does exist; download incremental updates.
+		if err = vcs.download(root); err != nil {
+			return err
+		}
+	}
+
+	if buildN {
+		// Do not show tag sync in -n; it's noise more than anything,
+		// and since we're not running commands, no tag will be found.
+		// But avoid printing nothing.
+		fmt.Fprintf(os.Stderr, "# cd %s; %s sync/update\n", root, vcs.cmd)
+		return nil
+	}
+
+	// Select and sync to appropriate version of the repository.
+	tags, err := vcs.tags(root)
+	if err != nil {
+		return err
+	}
+	vers := runtime.Version()
+	if i := strings.Index(vers, " "); i >= 0 {
+		vers = vers[:i]
+	}
+	if err := vcs.tagSync(root, selectTag(vers, tags)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// goTag matches go release tags such as go1 and go1.2.3.
+// The numbers involved must be small (at most 4 digits),
+// have no unnecessary leading zeros, and the version cannot
+// end in .0 - it is go1, not go1.0 or go1.0.0.
+var goTag = regexp.MustCompile(
+	`^go((0|[1-9][0-9]{0,3})\.)*([1-9][0-9]{0,3})$`,
+)
+
+// selectTag returns the closest matching tag for a given version.
+// Closest means the latest one that is not after the current release.
+// Version "goX" (or "goX.Y" or "goX.Y.Z") matches tags of the same form.
+// Version "release.rN" matches tags of the form "go.rN" (N being a floating-point number).
+// Version "weekly.YYYY-MM-DD" matches tags like "go.weekly.YYYY-MM-DD".
+//
+// NOTE(rsc): Eventually we will need to decide on some logic here.
+// For now, there is only "go1".  This matches the docs in go help get.
+func selectTag(goVersion string, tags []string) (match string) {
+	for _, t := range tags {
+		if t == "go1" {
+			return "go1"
+		}
+	}
+	return ""
+
+	/*
+		if goTag.MatchString(goVersion) {
+			v := goVersion
+			for _, t := range tags {
+				if !goTag.MatchString(t) {
+					continue
+				}
+				if cmpGoVersion(match, t) < 0 && cmpGoVersion(t, v) <= 0 {
+					match = t
+				}
+			}
+		}
+
+		return match
+	*/
+}
+
+// cmpGoVersion returns -1, 0, +1 reporting whether
+// x < y, x == y, or x > y.
+func cmpGoVersion(x, y string) int {
+	// Malformed strings compare less than well-formed strings.
+	if !goTag.MatchString(x) {
+		return -1
+	}
+	if !goTag.MatchString(y) {
+		return +1
+	}
+
+	// Compare numbers in sequence.
+	xx := strings.Split(x[len("go"):], ".")
+	yy := strings.Split(y[len("go"):], ".")
+
+	for i := 0; i < len(xx) && i < len(yy); i++ {
+		// The Atoi are guaranteed to succeed
+		// because the versions match goTag.
+		xi, _ := strconv.Atoi(xx[i])
+		yi, _ := strconv.Atoi(yy[i])
+		if xi < yi {
+			return -1
+		} else if xi > yi {
+			return +1
+		}
+	}
+
+	if len(xx) < len(yy) {
+		return -1
+	}
+	if len(xx) > len(yy) {
+		return +1
+	}
+	return 0
+}

libgo/go/cmd/go/go11.go

@@ -0,0 +1,10 @@
+// Copyright 2013 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.
+
+// +build go1.1
+
+package main
+
+// Test that go1.1 tag above is included in builds. main.go refers to this definition.
+const go11tag = true

libgo/go/cmd/go/help.go

@@ -0,0 +1,337 @@
+// Copyright 2011 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.
+
+package main
+
+var helpC = &Command{
+	UsageLine: "c",
+	Short:     "calling between Go and C",
+	Long: `
+There are two different ways to call between Go and C/C++ code.
+
+The first is the cgo tool, which is part of the Go distribution.  For
+information on how to use it see the cgo documentation (godoc cmd/cgo).
+
+The second is the SWIG program, which is a general tool for
+interfacing between languages.  For information on SWIG see
+http://swig.org/.  When running go build, any file with a .swig
+extension will be passed to SWIG.  Any file with a .swigcxx extension
+will be passed to SWIG with the -c++ option.
+
+When either cgo or SWIG is used, go build will pass any .c, .m, .s,
+or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++
+compiler.  The CC or CXX environment variables may be set to determine
+the C or C++ compiler, respectively, to use.
+	`,
+}
+
+var helpPackages = &Command{
+	UsageLine: "packages",
+	Short:     "description of package lists",
+	Long: `
+Many commands apply to a set of packages:
+
+	go action [packages]
+
+Usually, [packages] is a list of import paths.
+
+An import path that is a rooted path or that begins with
+a . or .. element is interpreted as a file system path and
+denotes the package in that directory.
+
+Otherwise, the import path P denotes the package found in
+the directory DIR/src/P for some DIR listed in the GOPATH
+environment variable (see 'go help gopath').
+
+If no import paths are given, the action applies to the
+package in the current directory.
+
+There are three reserved names for paths that should not be used
+for packages to be built with the go tool:
+
+- "main" denotes the top-level package in a stand-alone executable.
+
+- "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.
+
+- "std" is like all but expands to just the packages in the standard
+Go library.
+
+An import path is a pattern if it includes one or more "..." wildcards,
+each of which can match any string, including the empty string and
+strings containing slashes.  Such a pattern expands to all package
+directories found in the GOPATH trees with names matching the
+patterns.  As a special case, x/... matches x as well as x's subdirectories.
+For example, net/... expands to net and packages in its subdirectories.
+
+An import path can also name a package to be downloaded from
+a remote repository.  Run 'go help importpath' for details.
+
+Every package in a program must have a unique import path.
+By convention, this is arranged by starting each path with a
+unique prefix that belongs to you.  For example, paths used
+internally at Google all begin with 'google', and paths
+denoting remote repositories begin with the path to the code,
+such as 'code.google.com/p/project'.
+
+As a special case, if the package list is a list of .go files from a
+single directory, the command is applied to a single synthesized
+package made up of exactly those files, ignoring any build constraints
+in those files and ignoring any other files in the directory.
+
+File names that begin with "." or "_" are ignored by the go tool.
+	`,
+}
+
+var helpImportPath = &Command{
+	UsageLine: "importpath",
+	Short:     "import path syntax",
+	Long: `
+
+An import path (see 'go help packages') denotes a package
+stored in the local file system.  In general, an import path denotes
+either a standard package (such as "unicode/utf8") or a package
+found in one of the work spaces (see 'go help gopath').
+
+Relative import paths
+
+An import path beginning with ./ or ../ is called a relative path.
+The toolchain supports relative import paths as a shortcut in two ways.
+
+First, a relative path can be used as a shorthand on the command line.
+If you are working in the directory containing the code imported as
+"unicode" and want to run the tests for "unicode/utf8", you can type
+"go test ./utf8" instead of needing to specify the full path.
+Similarly, in the reverse situation, "go test .." will test "unicode" from
+the "unicode/utf8" directory. Relative patterns are also allowed, like
+"go test ./..." to test all subdirectories. See 'go help packages' for details
+on the pattern syntax.
+
+Second, if you are compiling a Go program not in a work space,
+you can use a relative path in an import statement in that program
+to refer to nearby code also not in a work space.
+This makes it easy to experiment with small multipackage programs
+outside of the usual work spaces, but such programs cannot be
+installed with "go install" (there is no work space in which to install them),
+so they are rebuilt from scratch each time they are built.
+To avoid ambiguity, Go programs cannot use relative import paths
+within a work space.
+
+Remote import paths
+
+Certain import paths also
+describe how to obtain the source code for the package using
+a revision control system.
+
+A few common code hosting sites have special syntax:
+
+	Bitbucket (Git, Mercurial)
+
+		import "bitbucket.org/user/project"
+		import "bitbucket.org/user/project/sub/directory"
+
+	GitHub (Git)
+
+		import "github.com/user/project"
+		import "github.com/user/project/sub/directory"
+
+	Google Code Project Hosting (Git, Mercurial, Subversion)
+
+		import "code.google.com/p/project"
+		import "code.google.com/p/project/sub/directory"
+
+		import "code.google.com/p/project.subrepository"
+		import "code.google.com/p/project.subrepository/sub/directory"
+
+	Launchpad (Bazaar)
+
+		import "launchpad.net/project"
+		import "launchpad.net/project/series"
+		import "launchpad.net/project/series/sub/directory"
+
+		import "launchpad.net/~user/project/branch"
+		import "launchpad.net/~user/project/branch/sub/directory"
+
+For code hosted on other servers, import paths may either be qualified
+with the version control type, or the go tool can dynamically fetch
+the import path over https/http and discover where the code resides
+from a <meta> tag in the HTML.
+
+To declare the code location, an import path of the form
+
+	repository.vcs/path
+
+specifies the given repository, with or without the .vcs suffix,
+using the named version control system, and then the path inside
+that repository.  The supported version control systems are:
+
+	Bazaar      .bzr
+	Git         .git
+	Mercurial   .hg
+	Subversion  .svn
+
+For example,
+
+	import "example.org/user/foo.hg"
+
+denotes the root directory of the Mercurial repository at
+example.org/user/foo or foo.hg, and
+
+	import "example.org/repo.git/foo/bar"
+
+denotes the foo/bar directory of the Git repository at
+example.org/repo or repo.git.
+
+When a version control system supports multiple protocols,
+each is tried in turn when downloading.  For example, a Git
+download tries git://, then https://, then http://.
+
+If the import path is not a known code hosting site and also lacks a
+version control qualifier, the go tool attempts to fetch the import
+over https/http and looks for a <meta> tag in the document's HTML
+<head>.
+
+The meta tag has the form:
+
+	<meta name="go-import" content="import-prefix vcs repo-root">
+
+The import-prefix is the import path corresponding to the repository
+root. It must be a prefix or an exact match of the package being
+fetched with "go get". If it's not an exact match, another http
+request is made at the prefix to verify the <meta> tags match.
+
+The vcs is one of "git", "hg", "svn", etc,
+
+The repo-root is the root of the version control system
+containing a scheme and not containing a .vcs qualifier.
+
+For example,
+
+	import "example.org/pkg/foo"
+
+will result in the following request(s):
+
+	https://example.org/pkg/foo?go-get=1 (preferred)
+	http://example.org/pkg/foo?go-get=1  (fallback)
+
+If that page contains the meta tag
+
+	<meta name="go-import" content="example.org git https://code.org/r/p/exproj">
+
+the go tool will verify that https://example.org/?go-get=1 contains the
+same meta tag and then git clone https://code.org/r/p/exproj into
+GOPATH/src/example.org.
+
+New downloaded packages are written to the first directory
+listed in the GOPATH environment variable (see 'go help gopath').
+
+The go command attempts to download the version of the
+package appropriate for the Go release being used.
+Run 'go help install' for more.
+	`,
+}
+
+var helpGopath = &Command{
+	UsageLine: "gopath",
+	Short:     "GOPATH environment variable",
+	Long: `
+The Go path is used to resolve import statements.
+It is implemented by and documented in the go/build package.
+
+The GOPATH environment variable lists places to look for Go code.
+On Unix, the value is a colon-separated string.
+On Windows, the value is a semicolon-separated string.
+On Plan 9, the value is a list.
+
+GOPATH must be set to get, build and install packages outside the
+standard Go tree.
+
+Each directory listed in GOPATH must have a prescribed structure:
+
+The src/ directory holds source code.  The path below 'src'
+determines the import path or executable name.
+
+The pkg/ directory holds installed package objects.
+As in the Go tree, each target operating system and
+architecture pair has its own subdirectory of pkg
+(pkg/GOOS_GOARCH).
+
+If DIR is a directory listed in the GOPATH, a package with
+source in DIR/src/foo/bar can be imported as "foo/bar" and
+has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a".
+
+The bin/ directory holds compiled commands.
+Each command is named for its source directory, but only
+the final element, not the entire path.  That is, the
+command with source in DIR/src/foo/quux is installed into
+DIR/bin/quux, not DIR/bin/foo/quux.  The foo/ is stripped
+so that you can add DIR/bin to your PATH to get at the
+installed commands.  If the GOBIN environment variable is
+set, commands are installed to the directory it names instead
+of DIR/bin.
+
+Here's an example directory layout:
+
+    GOPATH=/home/user/gocode
+
+    /home/user/gocode/
+        src/
+            foo/
+                bar/               (go code in package bar)
+                    x.go
+                quux/              (go code in package main)
+                    y.go
+        bin/
+            quux                   (installed command)
+        pkg/
+            linux_amd64/
+                foo/
+                    bar.a          (installed package object)
+
+Go searches each directory listed in GOPATH to find source code,
+but new packages are always downloaded into the first directory
+in the list.
+	`,
+}
+
+var helpFileType = &Command{
+	UsageLine: "filetype",
+	Short:     "file types",
+	Long: `
+The go command examines the contents of a restricted set of files
+in each directory. It identifies which files to examine based on
+the extension of the file name. These extensions are:
+
+	.go
+		Go source files.
+	.c, .h
+		C source files.
+		If the package uses cgo, these will be compiled with the
+		OS-native compiler (typically gcc); otherwise they will be
+		compiled with the Go-specific support compiler,
+		5c, 6c, or 8c, etc. as appropriate.
+	.cc, .cpp, .cxx, .hh, .hpp, .hxx
+		C++ source files. Only useful with cgo or SWIG, and always
+		compiled with the OS-native compiler.
+	.m
+		Objective-C source files. Only useful with cgo, and always
+		compiled with the OS-native compiler.
+	.s, .S
+		Assembler source files.
+		If the package uses cgo, these will be assembled with the
+		OS-native assembler (typically gcc (sic)); otherwise they
+		will be assembled with the Go-specific support assembler,
+		5a, 6a, or 8a, etc., as appropriate.
+	.swig, .swigcxx
+		SWIG definition files.
+	.syso
+		System object files.
+
+Files of each of these types except .syso may contain build
+constraints, but the go command stops scanning for build constraints
+at the first item in the file that is not a blank line or //-style
+line comment.
+	`,
+}

libgo/go/cmd/go/http.go

@@ -0,0 +1,87 @@
+// Copyright 2012 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.
+
+// +build !cmd_go_bootstrap
+
+// This code is compiled into the real 'go' binary, but it is not
+// compiled into the binary that is built during all.bash, so as
+// to avoid needing to build net (and thus use cgo) during the
+// bootstrap process.
+
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/url"
+)
+
+// httpClient is the default HTTP client, but a variable so it can be
+// changed by tests, without modifying http.DefaultClient.
+var httpClient = http.DefaultClient
+
+// httpGET returns the data from an HTTP GET request for the given URL.
+func httpGET(url string) ([]byte, error) {
+	resp, err := httpClient.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("%s: %s", url, resp.Status)
+	}
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %v", url, err)
+	}
+	return b, nil
+}
+
+// httpsOrHTTP returns the body of either the importPath's
+// https resource or, if unavailable, the http resource.
+func httpsOrHTTP(importPath string) (urlStr string, body io.ReadCloser, err error) {
+	fetch := func(scheme string) (urlStr string, res *http.Response, err error) {
+		u, err := url.Parse(scheme + "://" + importPath)
+		if err != nil {
+			return "", nil, err
+		}
+		u.RawQuery = "go-get=1"
+		urlStr = u.String()
+		if buildV {
+			log.Printf("Fetching %s", urlStr)
+		}
+		res, err = httpClient.Get(urlStr)
+		return
+	}
+	closeBody := func(res *http.Response) {
+		if res != nil {
+			res.Body.Close()
+		}
+	}
+	urlStr, res, err := fetch("https")
+	if err != nil || res.StatusCode != 200 {
+		if buildV {
+			if err != nil {
+				log.Printf("https fetch failed.")
+			} else {
+				log.Printf("ignoring https fetch with status code %d", res.StatusCode)
+			}
+		}
+		closeBody(res)
+		urlStr, res, err = fetch("http")
+	}
+	if err != nil {
+		closeBody(res)
+		return "", nil, err
+	}
+	// Note: accepting a non-200 OK here, so people can serve a
+	// meta import in their http 404 page.
+	if buildV {
+		log.Printf("Parsing meta tags from %s (status code %d)", urlStr, res.StatusCode)
+	}
+	return urlStr, res.Body, nil
+}

libgo/go/cmd/go/list.go

@@ -0,0 +1,208 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"bufio"
+	"encoding/json"
+	"io"
+	"os"
+	"strings"
+	"text/template"
+)
+
+var cmdList = &Command{
+	UsageLine: "list [-e] [-f format] [-json] [build flags] [packages]",
+	Short:     "list packages",
+	Long: `
+List lists the packages named by the import paths, one per line.
+
+The default output shows the package import path:
+
+    code.google.com/p/google-api-go-client/books/v1
+    code.google.com/p/goauth2/oauth
+    code.google.com/p/sqlite
+
+The -f flag specifies an alternate format for the list, using the
+syntax of package template.  The default output is equivalent to -f
+'{{.ImportPath}}'. The struct being passed to the template is:
+
+    type Package struct {
+        Dir        string // directory containing package sources
+        ImportPath string // import path of package in dir
+        Name       string // package name
+        Doc        string // package documentation string
+        Target     string // install path
+        Goroot     bool   // is this package in the Go root?
+        Standard   bool   // is this package part of the standard Go library?
+        Stale      bool   // would 'go install' do anything for this package?
+        Root       string // Go root or Go path dir containing this package
+
+        // Source files
+        GoFiles  []string       // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+        CgoFiles []string       // .go sources files that import "C"
+        IgnoredGoFiles []string // .go sources ignored due to build constraints
+        CFiles   []string       // .c source files
+        CXXFiles []string       // .cc, .cxx and .cpp source files
+        MFiles   []string       // .m source files
+        HFiles   []string       // .h, .hh, .hpp and .hxx source files
+        SFiles   []string       // .s source files
+        SwigFiles []string      // .swig files
+        SwigCXXFiles []string   // .swigcxx files
+        SysoFiles []string      // .syso object files to add to archive
+
+        // Cgo directives
+        CgoCFLAGS    []string // cgo: flags for C compiler
+        CgoCPPFLAGS  []string // cgo: flags for C preprocessor
+        CgoCXXFLAGS  []string // cgo: flags for C++ compiler
+        CgoLDFLAGS   []string // cgo: flags for linker
+        CgoPkgConfig []string // cgo: pkg-config names
+
+        // Dependency information
+        Imports []string // import paths used by this package
+        Deps    []string // all (recursively) imported dependencies
+
+        // Error information
+        Incomplete bool            // this package or a dependency has an error
+        Error      *PackageError   // error loading package
+        DepsErrors []*PackageError // errors loading dependencies
+
+        TestGoFiles  []string // _test.go files in package
+        TestImports  []string // imports from TestGoFiles
+        XTestGoFiles []string // _test.go files outside package
+        XTestImports []string // imports from XTestGoFiles
+    }
+
+The template function "join" calls strings.Join.
+
+The template function "context" returns the build context, defined as:
+
+	type Context struct {
+		GOARCH        string   // target architecture
+		GOOS          string   // target operating system
+		GOROOT        string   // Go root
+		GOPATH        string   // Go path
+		CgoEnabled    bool     // whether cgo can be used
+		UseAllFiles   bool     // use files regardless of +build lines, file names
+		Compiler      string   // compiler to assume when computing target paths
+		BuildTags     []string // build constraints to match in +build lines
+		ReleaseTags   []string // releases the current release is compatible with
+		InstallSuffix string   // suffix to use in the name of the install dir
+	}
+
+For more information about the meaning of these fields see the documentation
+for the go/build package's Context type.
+
+The -json flag causes the package data to be printed in JSON format
+instead of using the template format.
+
+The -e flag changes the handling of erroneous packages, those that
+cannot be found or are malformed.  By default, the list command
+prints an error to standard error for each erroneous package and
+omits the packages from consideration during the usual printing.
+With the -e flag, the list command never prints errors to standard
+error and instead processes the erroneous packages with the usual
+printing.  Erroneous packages will have a non-empty ImportPath and
+a non-nil Error field; other information may or may not be missing
+(zeroed).
+
+For more about build flags, see 'go help build'.
+
+For more about specifying packages, see 'go help packages'.
+	`,
+}
+
+func init() {
+	cmdList.Run = runList // break init cycle
+	addBuildFlags(cmdList)
+}
+
+var listE = cmdList.Flag.Bool("e", false, "")
+var listFmt = cmdList.Flag.String("f", "{{.ImportPath}}", "")
+var listJson = cmdList.Flag.Bool("json", false, "")
+var nl = []byte{'\n'}
+
+func runList(cmd *Command, args []string) {
+	out := newTrackingWriter(os.Stdout)
+	defer out.w.Flush()
+
+	var do func(*Package)
+	if *listJson {
+		do = func(p *Package) {
+			b, err := json.MarshalIndent(p, "", "\t")
+			if err != nil {
+				out.Flush()
+				fatalf("%s", err)
+			}
+			out.Write(b)
+			out.Write(nl)
+		}
+	} else {
+		var cachedCtxt *Context
+		context := func() *Context {
+			if cachedCtxt == nil {
+				cachedCtxt = newContext(&buildContext)
+			}
+			return cachedCtxt
+		}
+		fm := template.FuncMap{
+			"join":    strings.Join,
+			"context": context,
+		}
+		tmpl, err := template.New("main").Funcs(fm).Parse(*listFmt)
+		if err != nil {
+			fatalf("%s", err)
+		}
+		do = func(p *Package) {
+			if err := tmpl.Execute(out, p); err != nil {
+				out.Flush()
+				fatalf("%s", err)
+			}
+			if out.NeedNL() {
+				out.Write(nl)
+			}
+		}
+	}
+
+	load := packages
+	if *listE {
+		load = packagesAndErrors
+	}
+
+	for _, pkg := range load(args) {
+		do(pkg)
+	}
+}
+
+// TrackingWriter tracks the last byte written on every write so
+// we can avoid printing a newline if one was already written or
+// if there is no output at all.
+type TrackingWriter struct {
+	w    *bufio.Writer
+	last byte
+}
+
+func newTrackingWriter(w io.Writer) *TrackingWriter {
+	return &TrackingWriter{
+		w:    bufio.NewWriter(w),
+		last: '\n',
+	}
+}
+
+func (t *TrackingWriter) Write(p []byte) (n int, err error) {
+	n, err = t.w.Write(p)
+	if n > 0 {
+		t.last = p[n-1]
+	}
+	return
+}
+
+func (t *TrackingWriter) Flush() {
+	t.w.Flush()
+}
+
+func (t *TrackingWriter) NeedNL() bool {
+	return t.last != '\n'
+}

libgo/go/cmd/go/main.go

@@ -0,0 +1,722 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/build"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+	"sync"
+	"text/template"
+	"unicode"
+	"unicode/utf8"
+)
+
+// A Command is an implementation of a go command
+// like go build or go fix.
+type Command struct {
+	// Run runs the command.
+	// The args are the arguments after the command name.
+	Run func(cmd *Command, args []string)
+
+	// UsageLine is the one-line usage message.
+	// The first word in the line is taken to be the command name.
+	UsageLine string
+
+	// Short is the short description shown in the 'go help' output.
+	Short string
+
+	// Long is the long message shown in the 'go help <this-command>' output.
+	Long string
+
+	// Flag is a set of flags specific to this command.
+	Flag flag.FlagSet
+
+	// CustomFlags indicates that the command will do its own
+	// flag parsing.
+	CustomFlags bool
+}
+
+// Name returns the command's name: the first word in the usage line.
+func (c *Command) Name() string {
+	name := c.UsageLine
+	i := strings.Index(name, " ")
+	if i >= 0 {
+		name = name[:i]
+	}
+	return name
+}
+
+func (c *Command) Usage() {
+	fmt.Fprintf(os.Stderr, "usage: %s\n\n", c.UsageLine)
+	fmt.Fprintf(os.Stderr, "%s\n", strings.TrimSpace(c.Long))
+	os.Exit(2)
+}
+
+// Runnable reports whether the command can be run; otherwise
+// it is a documentation pseudo-command such as importpath.
+func (c *Command) Runnable() bool {
+	return c.Run != nil
+}
+
+// Commands lists the available commands and help topics.
+// The order here is the order in which they are printed by 'go help'.
+var commands = []*Command{
+	cmdBuild,
+	cmdClean,
+	cmdEnv,
+	cmdFix,
+	cmdFmt,
+	cmdGet,
+	cmdInstall,
+	cmdList,
+	cmdRun,
+	cmdTest,
+	cmdTool,
+	cmdVersion,
+	cmdVet,
+
+	helpC,
+	helpFileType,
+	helpGopath,
+	helpImportPath,
+	helpPackages,
+	helpTestflag,
+	helpTestfunc,
+}
+
+var exitStatus = 0
+var exitMu sync.Mutex
+
+func setExitStatus(n int) {
+	exitMu.Lock()
+	if exitStatus < n {
+		exitStatus = n
+	}
+	exitMu.Unlock()
+}
+
+func main() {
+	_ = go11tag
+	flag.Usage = usage
+	flag.Parse()
+	log.SetFlags(0)
+
+	args := flag.Args()
+	if len(args) < 1 {
+		usage()
+	}
+
+	if args[0] == "help" {
+		help(args[1:])
+		return
+	}
+
+	// Diagnose common mistake: GOPATH==GOROOT.
+	// This setting is equivalent to not setting GOPATH at all,
+	// which is not what most people want when they do it.
+	if gopath := os.Getenv("GOPATH"); gopath == runtime.GOROOT() {
+		fmt.Fprintf(os.Stderr, "warning: GOPATH set to GOROOT (%s) has no effect\n", gopath)
+	} else {
+		for _, p := range filepath.SplitList(gopath) {
+			// Note: using HasPrefix instead of Contains because a ~ can appear
+			// in the middle of directory elements, such as /tmp/git-1.8.2~rc3
+			// or C:\PROGRA~1. Only ~ as a path prefix has meaning to the shell.
+			if strings.HasPrefix(p, "~") {
+				fmt.Fprintf(os.Stderr, "go: GOPATH entry cannot start with shell metacharacter '~': %q\n", p)
+				os.Exit(2)
+			}
+			if build.IsLocalImport(p) {
+				fmt.Fprintf(os.Stderr, "go: GOPATH entry is relative; must be absolute path: %q.\nRun 'go help gopath' for usage.\n", p)
+				os.Exit(2)
+			}
+		}
+	}
+
+	if fi, err := os.Stat(goroot); err != nil || !fi.IsDir() {
+		fmt.Fprintf(os.Stderr, "go: cannot find GOROOT directory: %v\n", goroot)
+		os.Exit(2)
+	}
+
+	for _, cmd := range commands {
+		if cmd.Name() == args[0] && cmd.Run != nil {
+			cmd.Flag.Usage = func() { cmd.Usage() }
+			if cmd.CustomFlags {
+				args = args[1:]
+			} else {
+				cmd.Flag.Parse(args[1:])
+				args = cmd.Flag.Args()
+			}
+			cmd.Run(cmd, args)
+			exit()
+			return
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "go: unknown subcommand %q\nRun 'go help' for usage.\n", args[0])
+	setExitStatus(2)
+	exit()
+}
+
+var usageTemplate = `Go is a tool for managing Go source code.
+
+Usage:
+
+	go command [arguments]
+
+The commands are:
+{{range .}}{{if .Runnable}}
+    {{.Name | printf "%-11s"}} {{.Short}}{{end}}{{end}}
+
+Use "go help [command]" for more information about a command.
+
+Additional help topics:
+{{range .}}{{if not .Runnable}}
+    {{.Name | printf "%-11s"}} {{.Short}}{{end}}{{end}}
+
+Use "go help [topic]" for more information about that topic.
+
+`
+
+var helpTemplate = `{{if .Runnable}}usage: go {{.UsageLine}}
+
+{{end}}{{.Long | trim}}
+`
+
+var documentationTemplate = `// Copyright 2011 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.
+
+// DO NOT EDIT THIS FILE. GENERATED BY mkdoc.sh.
+// Edit the documentation in other files and rerun mkdoc.sh to generate this one.
+
+/*
+{{range .}}{{if .Short}}{{.Short | capitalize}}
+
+{{end}}{{if .Runnable}}Usage:
+
+	go {{.UsageLine}}
+
+{{end}}{{.Long | trim}}
+
+
+{{end}}*/
+package main
+`
+
+// tmpl executes the given template text on data, writing the result to w.
+func tmpl(w io.Writer, text string, data interface{}) {
+	t := template.New("top")
+	t.Funcs(template.FuncMap{"trim": strings.TrimSpace, "capitalize": capitalize})
+	template.Must(t.Parse(text))
+	if err := t.Execute(w, data); err != nil {
+		panic(err)
+	}
+}
+
+func capitalize(s string) string {
+	if s == "" {
+		return s
+	}
+	r, n := utf8.DecodeRuneInString(s)
+	return string(unicode.ToTitle(r)) + s[n:]
+}
+
+func printUsage(w io.Writer) {
+	tmpl(w, usageTemplate, commands)
+}
+
+func usage() {
+	// special case "go test -h"
+	if len(os.Args) > 1 && os.Args[1] == "test" {
+		help([]string{"testflag"})
+		os.Exit(2)
+	}
+	printUsage(os.Stderr)
+	os.Exit(2)
+}
+
+// help implements the 'help' command.
+func help(args []string) {
+	if len(args) == 0 {
+		printUsage(os.Stdout)
+		// not exit 2: succeeded at 'go help'.
+		return
+	}
+	if len(args) != 1 {
+		fmt.Fprintf(os.Stderr, "usage: go help command\n\nToo many arguments given.\n")
+		os.Exit(2) // failed at 'go help'
+	}
+
+	arg := args[0]
+
+	// 'go help documentation' generates doc.go.
+	if arg == "documentation" {
+		buf := new(bytes.Buffer)
+		printUsage(buf)
+		usage := &Command{Long: buf.String()}
+		tmpl(os.Stdout, documentationTemplate, append([]*Command{usage}, commands...))
+		return
+	}
+
+	for _, cmd := range commands {
+		if cmd.Name() == arg {
+			tmpl(os.Stdout, helpTemplate, cmd)
+			// not exit 2: succeeded at 'go help cmd'.
+			return
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "Unknown help topic %#q.  Run 'go help'.\n", arg)
+	os.Exit(2) // failed at 'go help cmd'
+}
+
+// importPathsNoDotExpansion returns the import paths to use for the given
+// command line, but it does no ... expansion.
+func importPathsNoDotExpansion(args []string) []string {
+	if len(args) == 0 {
+		return []string{"."}
+	}
+	var out []string
+	for _, a := range args {
+		// Arguments are supposed to be import paths, but
+		// as a courtesy to Windows developers, rewrite \ to /
+		// in command-line arguments.  Handles .\... and so on.
+		if filepath.Separator == '\\' {
+			a = strings.Replace(a, `\`, `/`, -1)
+		}
+
+		// Put argument in canonical form, but preserve leading ./.
+		if strings.HasPrefix(a, "./") {
+			a = "./" + path.Clean(a)
+			if a == "./." {
+				a = "."
+			}
+		} else {
+			a = path.Clean(a)
+		}
+		if a == "all" || a == "std" {
+			out = append(out, allPackages(a)...)
+			continue
+		}
+		out = append(out, a)
+	}
+	return out
+}
+
+// importPaths returns the import paths to use for the given command line.
+func importPaths(args []string) []string {
+	args = importPathsNoDotExpansion(args)
+	var out []string
+	for _, a := range args {
+		if strings.Contains(a, "...") {
+			if build.IsLocalImport(a) {
+				out = append(out, allPackagesInFS(a)...)
+			} else {
+				out = append(out, allPackages(a)...)
+			}
+			continue
+		}
+		out = append(out, a)
+	}
+	return out
+}
+
+var atexitFuncs []func()
+
+func atexit(f func()) {
+	atexitFuncs = append(atexitFuncs, f)
+}
+
+func exit() {
+	for _, f := range atexitFuncs {
+		f()
+	}
+	os.Exit(exitStatus)
+}
+
+func fatalf(format string, args ...interface{}) {
+	errorf(format, args...)
+	exit()
+}
+
+func errorf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+	setExitStatus(1)
+}
+
+var logf = log.Printf
+
+func exitIfErrors() {
+	if exitStatus != 0 {
+		exit()
+	}
+}
+
+func run(cmdargs ...interface{}) {
+	cmdline := stringList(cmdargs...)
+	if buildN || buildX {
+		fmt.Printf("%s\n", strings.Join(cmdline, " "))
+		if buildN {
+			return
+		}
+	}
+
+	cmd := exec.Command(cmdline[0], cmdline[1:]...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		errorf("%v", err)
+	}
+}
+
+func runOut(dir string, cmdargs ...interface{}) []byte {
+	cmdline := stringList(cmdargs...)
+	cmd := exec.Command(cmdline[0], cmdline[1:]...)
+	cmd.Dir = dir
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		os.Stderr.Write(out)
+		errorf("%v", err)
+		out = nil
+	}
+	return out
+}
+
+// envForDir returns a copy of the environment
+// suitable for running in the given directory.
+// The environment is the current process's environment
+// but with an updated $PWD, so that an os.Getwd in the
+// child will be faster.
+func envForDir(dir string) []string {
+	env := os.Environ()
+	// Internally we only use rooted paths, so dir is rooted.
+	// Even if dir is not rooted, no harm done.
+	return mergeEnvLists([]string{"PWD=" + dir}, env)
+}
+
+// mergeEnvLists merges the two environment lists such that
+// variables with the same name in "in" replace those in "out".
+func mergeEnvLists(in, out []string) []string {
+NextVar:
+	for _, inkv := range in {
+		k := strings.SplitAfterN(inkv, "=", 2)[0]
+		for i, outkv := range out {
+			if strings.HasPrefix(outkv, k) {
+				out[i] = inkv
+				continue NextVar
+			}
+		}
+		out = append(out, inkv)
+	}
+	return out
+}
+
+// matchPattern(pattern)(name) reports whether
+// name matches pattern.  Pattern is a limited glob
+// pattern in which '...' means 'any string' and there
+// is no other special syntax.
+func matchPattern(pattern string) func(name string) bool {
+	re := regexp.QuoteMeta(pattern)
+	re = strings.Replace(re, `\.\.\.`, `.*`, -1)
+	// Special case: foo/... matches foo too.
+	if strings.HasSuffix(re, `/.*`) {
+		re = re[:len(re)-len(`/.*`)] + `(/.*)?`
+	}
+	reg := regexp.MustCompile(`^` + re + `$`)
+	return func(name string) bool {
+		return reg.MatchString(name)
+	}
+}
+
+// hasPathPrefix reports whether the path s begins with the
+// elements in prefix.
+func hasPathPrefix(s, prefix string) bool {
+	switch {
+	default:
+		return false
+	case len(s) == len(prefix):
+		return s == prefix
+	case len(s) > len(prefix):
+		if prefix != "" && prefix[len(prefix)-1] == '/' {
+			return strings.HasPrefix(s, prefix)
+		}
+		return s[len(prefix)] == '/' && s[:len(prefix)] == prefix
+	}
+}
+
+// treeCanMatchPattern(pattern)(name) reports whether
+// name or children of name can possibly match pattern.
+// Pattern is the same limited glob accepted by matchPattern.
+func treeCanMatchPattern(pattern string) func(name string) bool {
+	wildCard := false
+	if i := strings.Index(pattern, "..."); i >= 0 {
+		wildCard = true
+		pattern = pattern[:i]
+	}
+	return func(name string) bool {
+		return len(name) <= len(pattern) && hasPathPrefix(pattern, name) ||
+			wildCard && strings.HasPrefix(name, pattern)
+	}
+}
+
+// allPackages returns all the packages that can be found
+// under the $GOPATH directories and $GOROOT matching pattern.
+// The pattern is either "all" (all packages), "std" (standard packages)
+// or a path including "...".
+func allPackages(pattern string) []string {
+	pkgs := matchPackages(pattern)
+	if len(pkgs) == 0 {
+		fmt.Fprintf(os.Stderr, "warning: %q matched no packages\n", pattern)
+	}
+	return pkgs
+}
+
+func matchPackages(pattern string) []string {
+	match := func(string) bool { return true }
+	treeCanMatch := func(string) bool { return true }
+	if pattern != "all" && pattern != "std" {
+		match = matchPattern(pattern)
+		treeCanMatch = treeCanMatchPattern(pattern)
+	}
+
+	have := map[string]bool{
+		"builtin": true, // ignore pseudo-package that exists only for documentation
+	}
+	if !buildContext.CgoEnabled {
+		have["runtime/cgo"] = true // ignore during walk
+	}
+	var pkgs []string
+
+	// Commands
+	cmd := filepath.Join(goroot, "src/cmd") + string(filepath.Separator)
+	filepath.Walk(cmd, func(path string, fi os.FileInfo, err error) error {
+		if err != nil || !fi.IsDir() || path == cmd {
+			return nil
+		}
+		name := path[len(cmd):]
+		if !treeCanMatch(name) {
+			return filepath.SkipDir
+		}
+		// Commands are all in cmd/, not in subdirectories.
+		if strings.Contains(name, string(filepath.Separator)) {
+			return filepath.SkipDir
+		}
+
+		// We use, e.g., cmd/gofmt as the pseudo import path for gofmt.
+		name = "cmd/" + name
+		if have[name] {
+			return nil
+		}
+		have[name] = true
+		if !match(name) {
+			return nil
+		}
+		_, err = buildContext.ImportDir(path, 0)
+		if err != nil {
+			if _, noGo := err.(*build.NoGoError); !noGo {
+				log.Print(err)
+			}
+			return nil
+		}
+		pkgs = append(pkgs, name)
+		return nil
+	})
+
+	for _, src := range buildContext.SrcDirs() {
+		if pattern == "std" && src != gorootSrcPkg {
+			continue
+		}
+		src = filepath.Clean(src) + string(filepath.Separator)
+		filepath.Walk(src, func(path string, fi os.FileInfo, err error) error {
+			if err != nil || !fi.IsDir() || path == src {
+				return nil
+			}
+
+			// Avoid .foo, _foo, and testdata directory trees.
+			_, elem := filepath.Split(path)
+			if strings.HasPrefix(elem, ".") || strings.HasPrefix(elem, "_") || elem == "testdata" {
+				return filepath.SkipDir
+			}
+
+			name := filepath.ToSlash(path[len(src):])
+			if pattern == "std" && strings.Contains(name, ".") {
+				return filepath.SkipDir
+			}
+			if !treeCanMatch(name) {
+				return filepath.SkipDir
+			}
+			if have[name] {
+				return nil
+			}
+			have[name] = true
+			if !match(name) {
+				return nil
+			}
+			_, err = buildContext.ImportDir(path, 0)
+			if err != nil {
+				if _, noGo := err.(*build.NoGoError); noGo {
+					return nil
+				}
+			}
+			pkgs = append(pkgs, name)
+			return nil
+		})
+	}
+	return pkgs
+}
+
+// allPackagesInFS is like allPackages but is passed a pattern
+// beginning ./ or ../, meaning it should scan the tree rooted
+// at the given directory.  There are ... in the pattern too.
+func allPackagesInFS(pattern string) []string {
+	pkgs := matchPackagesInFS(pattern)
+	if len(pkgs) == 0 {
+		fmt.Fprintf(os.Stderr, "warning: %q matched no packages\n", pattern)
+	}
+	return pkgs
+}
+
+func matchPackagesInFS(pattern string) []string {
+	// Find directory to begin the scan.
+	// Could be smarter but this one optimization
+	// is enough for now, since ... is usually at the
+	// end of a path.
+	i := strings.Index(pattern, "...")
+	dir, _ := path.Split(pattern[:i])
+
+	// pattern begins with ./ or ../.
+	// path.Clean will discard the ./ but not the ../.
+	// We need to preserve the ./ for pattern matching
+	// and in the returned import paths.
+	prefix := ""
+	if strings.HasPrefix(pattern, "./") {
+		prefix = "./"
+	}
+	match := matchPattern(pattern)
+
+	var pkgs []string
+	filepath.Walk(dir, func(path string, fi os.FileInfo, err error) error {
+		if err != nil || !fi.IsDir() {
+			return nil
+		}
+		if path == dir {
+			// filepath.Walk starts at dir and recurses. For the recursive case,
+			// the path is the result of filepath.Join, which calls filepath.Clean.
+			// The initial case is not Cleaned, though, so we do this explicitly.
+			//
+			// This converts a path like "./io/" to "io". Without this step, running
+			// "cd $GOROOT/src/pkg; go list ./io/..." would incorrectly skip the io
+			// package, because prepending the prefix "./" to the unclean path would
+			// result in "././io", and match("././io") returns false.
+			path = filepath.Clean(path)
+		}
+
+		// Avoid .foo, _foo, and testdata directory trees, but do not avoid "." or "..".
+		_, elem := filepath.Split(path)
+		dot := strings.HasPrefix(elem, ".") && elem != "." && elem != ".."
+		if dot || strings.HasPrefix(elem, "_") || elem == "testdata" {
+			return filepath.SkipDir
+		}
+
+		name := prefix + filepath.ToSlash(path)
+		if !match(name) {
+			return nil
+		}
+		if _, err = build.ImportDir(path, 0); err != nil {
+			if _, noGo := err.(*build.NoGoError); !noGo {
+				log.Print(err)
+			}
+			return nil
+		}
+		pkgs = append(pkgs, name)
+		return nil
+	})
+	return pkgs
+}
+
+// stringList's arguments should be a sequence of string or []string values.
+// stringList flattens them into a single []string.
+func stringList(args ...interface{}) []string {
+	var x []string
+	for _, arg := range args {
+		switch arg := arg.(type) {
+		case []string:
+			x = append(x, arg...)
+		case string:
+			x = append(x, arg)
+		default:
+			panic("stringList: invalid argument")
+		}
+	}
+	return x
+}
+
+// toFold returns a string with the property that
+//	strings.EqualFold(s, t) iff toFold(s) == toFold(t)
+// This lets us test a large set of strings for fold-equivalent
+// duplicates without making a quadratic number of calls
+// to EqualFold. Note that strings.ToUpper and strings.ToLower
+// have the desired property in some corner cases.
+func toFold(s string) string {
+	// Fast path: all ASCII, no upper case.
+	// Most paths look like this already.
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if c >= utf8.RuneSelf || 'A' <= c && c <= 'Z' {
+			goto Slow
+		}
+	}
+	return s
+
+Slow:
+	var buf bytes.Buffer
+	for _, r := range s {
+		// SimpleFold(x) cycles to the next equivalent rune > x
+		// or wraps around to smaller values. Iterate until it wraps,
+		// and we've found the minimum value.
+		for {
+			r0 := r
+			r = unicode.SimpleFold(r0)
+			if r <= r0 {
+				break
+			}
+		}
+		// Exception to allow fast path above: A-Z => a-z
+		if 'A' <= r && r <= 'Z' {
+			r += 'a' - 'A'
+		}
+		buf.WriteRune(r)
+	}
+	return buf.String()
+}
+
+// foldDup reports a pair of strings from the list that are
+// equal according to strings.EqualFold.
+// It returns "", "" if there are no such strings.
+func foldDup(list []string) (string, string) {
+	clash := map[string]string{}
+	for _, s := range list {
+		fold := toFold(s)
+		if t := clash[fold]; t != "" {
+			if s > t {
+				s, t = t, s
+			}
+			return s, t
+		}
+		clash[fold] = s
+	}
+	return "", ""
+}

libgo/go/cmd/go/match_test.go

@@ -0,0 +1,88 @@
+// Copyright 2012 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.
+
+package main
+
+import "testing"
+
+var matchPatternTests = []stringPairTest{
+	{"...", "foo", true},
+	{"net", "net", true},
+	{"net", "net/http", false},
+	{"net/http", "net", false},
+	{"net/http", "net/http", true},
+	{"net...", "netchan", true},
+	{"net...", "net", true},
+	{"net...", "net/http", true},
+	{"net...", "not/http", false},
+	{"net/...", "netchan", false},
+	{"net/...", "net", true},
+	{"net/...", "net/http", true},
+	{"net/...", "not/http", false},
+}
+
+func TestMatchPattern(t *testing.T) {
+	testStringPairs(t, "matchPattern", matchPatternTests, func(pattern, name string) bool {
+		return matchPattern(pattern)(name)
+	})
+}
+
+var treeCanMatchPatternTests = []stringPairTest{
+	{"...", "foo", true},
+	{"net", "net", true},
+	{"net", "net/http", false},
+	{"net/http", "net", true},
+	{"net/http", "net/http", true},
+	{"net...", "netchan", true},
+	{"net...", "net", true},
+	{"net...", "net/http", true},
+	{"net...", "not/http", false},
+	{"net/...", "netchan", false},
+	{"net/...", "net", true},
+	{"net/...", "net/http", true},
+	{"net/...", "not/http", false},
+	{"abc.../def", "abcxyz", true},
+	{"abc.../def", "xyxabc", false},
+	{"x/y/z/...", "x", true},
+	{"x/y/z/...", "x/y", true},
+	{"x/y/z/...", "x/y/z", true},
+	{"x/y/z/...", "x/y/z/w", true},
+	{"x/y/z", "x", true},
+	{"x/y/z", "x/y", true},
+	{"x/y/z", "x/y/z", true},
+	{"x/y/z", "x/y/z/w", false},
+	{"x/.../y/z", "x/a/b/c", true},
+	{"x/.../y/z", "y/x/a/b/c", false},
+}
+
+func TestChildrenCanMatchPattern(t *testing.T) {
+	testStringPairs(t, "treeCanMatchPattern", treeCanMatchPatternTests, func(pattern, name string) bool {
+		return treeCanMatchPattern(pattern)(name)
+	})
+}
+
+var hasPathPrefixTests = []stringPairTest{
+	{"abc", "a", false},
+	{"a/bc", "a", true},
+	{"a", "a", true},
+	{"a/bc", "a/", true},
+}
+
+func TestHasPathPrefix(t *testing.T) {
+	testStringPairs(t, "hasPathPrefix", hasPathPrefixTests, hasPathPrefix)
+}
+
+type stringPairTest struct {
+	in1 string
+	in2 string
+	out bool
+}
+
+func testStringPairs(t *testing.T, name string, tests []stringPairTest, f func(string, string) bool) {
+	for _, tt := range tests {
+		if out := f(tt.in1, tt.in2); out != tt.out {
+			t.Errorf("%s(%q, %q) = %v, want %v", name, tt.in1, tt.in2, out, tt.out)
+		}
+	}
+}

libgo/go/cmd/go/mkdoc.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+# Copyright 2012 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.
+
+go install # So the next line will produce updated documentation.
+go help documentation > doc.go
+gofmt -w doc.go
+

libgo/go/cmd/go/pkg.go

@@ -0,0 +1,856 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"go/build"
+	"go/scanner"
+	"go/token"
+	"os"
+	pathpkg "path"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+	"unicode"
+)
+
+// A Package describes a single package found in a directory.
+type Package struct {
+	// Note: These fields are part of the go command's public API.
+	// See list.go.  It is okay to add fields, but not to change or
+	// remove existing ones.  Keep in sync with list.go
+	Dir         string `json:",omitempty"` // directory containing package sources
+	ImportPath  string `json:",omitempty"` // import path of package in dir
+	Name        string `json:",omitempty"` // package name
+	Doc         string `json:",omitempty"` // package documentation string
+	Target      string `json:",omitempty"` // install path
+	Goroot      bool   `json:",omitempty"` // is this package found in the Go root?
+	Standard    bool   `json:",omitempty"` // is this package part of the standard Go library?
+	Stale       bool   `json:",omitempty"` // would 'go install' do anything for this package?
+	Root        string `json:",omitempty"` // Go root or Go path dir containing this package
+	ConflictDir string `json:",omitempty"` // Dir is hidden by this other directory
+
+	// Source files
+	GoFiles        []string `json:",omitempty"` // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+	CgoFiles       []string `json:",omitempty"` // .go sources files that import "C"
+	IgnoredGoFiles []string `json:",omitempty"` // .go sources ignored due to build constraints
+	CFiles         []string `json:",omitempty"` // .c source files
+	CXXFiles       []string `json:",omitempty"` // .cc, .cpp and .cxx source files
+	MFiles         []string `json:",omitempty"` // .m source files
+	HFiles         []string `json:",omitempty"` // .h, .hh, .hpp and .hxx source files
+	SFiles         []string `json:",omitempty"` // .s source files
+	SwigFiles      []string `json:",omitempty"` // .swig files
+	SwigCXXFiles   []string `json:",omitempty"` // .swigcxx files
+	SysoFiles      []string `json:",omitempty"` // .syso system object files added to package
+
+	// Cgo directives
+	CgoCFLAGS    []string `json:",omitempty"` // cgo: flags for C compiler
+	CgoCPPFLAGS  []string `json:",omitempty"` // cgo: flags for C preprocessor
+	CgoCXXFLAGS  []string `json:",omitempty"` // cgo: flags for C++ compiler
+	CgoLDFLAGS   []string `json:",omitempty"` // cgo: flags for linker
+	CgoPkgConfig []string `json:",omitempty"` // cgo: pkg-config names
+
+	// Dependency information
+	Imports []string `json:",omitempty"` // import paths used by this package
+	Deps    []string `json:",omitempty"` // all (recursively) imported dependencies
+
+	// Error information
+	Incomplete bool            `json:",omitempty"` // was there an error loading this package or dependencies?
+	Error      *PackageError   `json:",omitempty"` // error loading this package (not dependencies)
+	DepsErrors []*PackageError `json:",omitempty"` // errors loading dependencies
+
+	// Test information
+	TestGoFiles  []string `json:",omitempty"` // _test.go files in package
+	TestImports  []string `json:",omitempty"` // imports from TestGoFiles
+	XTestGoFiles []string `json:",omitempty"` // _test.go files outside package
+	XTestImports []string `json:",omitempty"` // imports from XTestGoFiles
+
+	// Unexported fields are not part of the public API.
+	build        *build.Package
+	pkgdir       string // overrides build.PkgDir
+	imports      []*Package
+	deps         []*Package
+	gofiles      []string // GoFiles+CgoFiles+TestGoFiles+XTestGoFiles files, absolute paths
+	sfiles       []string
+	allgofiles   []string             // gofiles + IgnoredGoFiles, absolute paths
+	target       string               // installed file for this package (may be executable)
+	fake         bool                 // synthesized package
+	forceBuild   bool                 // this package must be rebuilt
+	forceLibrary bool                 // this package is a library (even if named "main")
+	cmdline      bool                 // defined by files listed on command line
+	local        bool                 // imported via local path (./ or ../)
+	localPrefix  string               // interpret ./ and ../ imports relative to this prefix
+	exeName      string               // desired name for temporary executable
+	coverMode    string               // preprocess Go source files with the coverage tool in this mode
+	coverVars    map[string]*CoverVar // variables created by coverage analysis
+	omitDWARF    bool                 // tell linker not to write DWARF information
+}
+
+// CoverVar holds the name of the generated coverage variables targeting the named file.
+type CoverVar struct {
+	File string // local file name
+	Var  string // name of count struct
+}
+
+func (p *Package) copyBuild(pp *build.Package) {
+	p.build = pp
+
+	p.Dir = pp.Dir
+	p.ImportPath = pp.ImportPath
+	p.Name = pp.Name
+	p.Doc = pp.Doc
+	p.Root = pp.Root
+	p.ConflictDir = pp.ConflictDir
+	// TODO? Target
+	p.Goroot = pp.Goroot
+	p.Standard = p.Goroot && p.ImportPath != "" && !strings.Contains(p.ImportPath, ".")
+	p.GoFiles = pp.GoFiles
+	p.CgoFiles = pp.CgoFiles
+	p.IgnoredGoFiles = pp.IgnoredGoFiles
+	p.CFiles = pp.CFiles
+	p.CXXFiles = pp.CXXFiles
+	p.MFiles = pp.MFiles
+	p.HFiles = pp.HFiles
+	p.SFiles = pp.SFiles
+	p.SwigFiles = pp.SwigFiles
+	p.SwigCXXFiles = pp.SwigCXXFiles
+	p.SysoFiles = pp.SysoFiles
+	p.CgoCFLAGS = pp.CgoCFLAGS
+	p.CgoCPPFLAGS = pp.CgoCPPFLAGS
+	p.CgoCXXFLAGS = pp.CgoCXXFLAGS
+	p.CgoLDFLAGS = pp.CgoLDFLAGS
+	p.CgoPkgConfig = pp.CgoPkgConfig
+	p.Imports = pp.Imports
+	p.TestGoFiles = pp.TestGoFiles
+	p.TestImports = pp.TestImports
+	p.XTestGoFiles = pp.XTestGoFiles
+	p.XTestImports = pp.XTestImports
+}
+
+// A PackageError describes an error loading information about a package.
+type PackageError struct {
+	ImportStack   []string // shortest path from package named on command line to this one
+	Pos           string   // position of error
+	Err           string   // the error itself
+	isImportCycle bool     // the error is an import cycle
+	hard          bool     // whether the error is soft or hard; soft errors are ignored in some places
+}
+
+func (p *PackageError) Error() string {
+	// Import cycles deserve special treatment.
+	if p.isImportCycle {
+		return fmt.Sprintf("%s\npackage %s\n", p.Err, strings.Join(p.ImportStack, "\n\timports "))
+	}
+	if p.Pos != "" {
+		// Omit import stack.  The full path to the file where the error
+		// is the most important thing.
+		return p.Pos + ": " + p.Err
+	}
+	if len(p.ImportStack) == 0 {
+		return p.Err
+	}
+	return "package " + strings.Join(p.ImportStack, "\n\timports ") + ": " + p.Err
+}
+
+// An importStack is a stack of import paths.
+type importStack []string
+
+func (s *importStack) push(p string) {
+	*s = append(*s, p)
+}
+
+func (s *importStack) pop() {
+	*s = (*s)[0 : len(*s)-1]
+}
+
+func (s *importStack) copy() []string {
+	return append([]string{}, *s...)
+}
+
+// shorterThan returns true if sp is shorter than t.
+// We use this to record the shortest import sequence
+// that leads to a particular package.
+func (sp *importStack) shorterThan(t []string) bool {
+	s := *sp
+	if len(s) != len(t) {
+		return len(s) < len(t)
+	}
+	// If they are the same length, settle ties using string ordering.
+	for i := range s {
+		if s[i] != t[i] {
+			return s[i] < t[i]
+		}
+	}
+	return false // they are equal
+}
+
+// packageCache is a lookup cache for loadPackage,
+// so that if we look up a package multiple times
+// we return the same pointer each time.
+var packageCache = map[string]*Package{}
+
+// reloadPackage is like loadPackage but makes sure
+// not to use the package cache.
+func reloadPackage(arg string, stk *importStack) *Package {
+	p := packageCache[arg]
+	if p != nil {
+		delete(packageCache, p.Dir)
+		delete(packageCache, p.ImportPath)
+	}
+	return loadPackage(arg, stk)
+}
+
+// dirToImportPath returns the pseudo-import path we use for a package
+// outside the Go path.  It begins with _/ and then contains the full path
+// to the directory.  If the package lives in c:\home\gopher\my\pkg then
+// the pseudo-import path is _/c_/home/gopher/my/pkg.
+// Using a pseudo-import path like this makes the ./ imports no longer
+// a special case, so that all the code to deal with ordinary imports works
+// automatically.
+func dirToImportPath(dir string) string {
+	return pathpkg.Join("_", strings.Map(makeImportValid, filepath.ToSlash(dir)))
+}
+
+func makeImportValid(r rune) rune {
+	// Should match Go spec, compilers, and ../../pkg/go/parser/parser.go:/isValidImport.
+	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
+	if !unicode.IsGraphic(r) || unicode.IsSpace(r) || strings.ContainsRune(illegalChars, r) {
+		return '_'
+	}
+	return r
+}
+
+// loadImport scans the directory named by path, which must be an import path,
+// but possibly a local import path (an absolute file system path or one beginning
+// with ./ or ../).  A local relative path is interpreted relative to srcDir.
+// It returns a *Package describing the package found in that directory.
+func loadImport(path string, srcDir string, stk *importStack, importPos []token.Position) *Package {
+	stk.push(path)
+	defer stk.pop()
+
+	// Determine canonical identifier for this package.
+	// For a local import the identifier is the pseudo-import path
+	// we create from the full directory to the package.
+	// Otherwise it is the usual import path.
+	importPath := path
+	isLocal := build.IsLocalImport(path)
+	if isLocal {
+		importPath = dirToImportPath(filepath.Join(srcDir, path))
+	}
+	if p := packageCache[importPath]; p != nil {
+		return reusePackage(p, stk)
+	}
+
+	p := new(Package)
+	p.local = isLocal
+	p.ImportPath = importPath
+	packageCache[importPath] = p
+
+	// Load package.
+	// Import always returns bp != nil, even if an error occurs,
+	// in order to return partial information.
+	//
+	// TODO: After Go 1, decide when to pass build.AllowBinary here.
+	// See issue 3268 for mistakes to avoid.
+	bp, err := buildContext.Import(path, srcDir, 0)
+	bp.ImportPath = importPath
+	if gobin != "" {
+		bp.BinDir = gobin
+	}
+	p.load(stk, bp, err)
+	if p.Error != nil && len(importPos) > 0 {
+		pos := importPos[0]
+		pos.Filename = shortPath(pos.Filename)
+		p.Error.Pos = pos.String()
+	}
+
+	return p
+}
+
+// reusePackage reuses package p to satisfy the import at the top
+// of the import stack stk.  If this use causes an import loop,
+// reusePackage updates p's error information to record the loop.
+func reusePackage(p *Package, stk *importStack) *Package {
+	// We use p.imports==nil to detect a package that
+	// is in the midst of its own loadPackage call
+	// (all the recursion below happens before p.imports gets set).
+	if p.imports == nil {
+		if p.Error == nil {
+			p.Error = &PackageError{
+				ImportStack:   stk.copy(),
+				Err:           "import cycle not allowed",
+				isImportCycle: true,
+			}
+		}
+		p.Incomplete = true
+	}
+	// Don't rewrite the import stack in the error if we have an import cycle.
+	// If we do, we'll lose the path that describes the cycle.
+	if p.Error != nil && !p.Error.isImportCycle && stk.shorterThan(p.Error.ImportStack) {
+		p.Error.ImportStack = stk.copy()
+	}
+	return p
+}
+
+type targetDir int
+
+const (
+	toRoot targetDir = iota // to bin dir inside package root (default)
+	toTool                  // GOROOT/pkg/tool
+	toBin                   // GOROOT/bin
+)
+
+// goTools is a map of Go program import path to install target directory.
+var goTools = map[string]targetDir{
+	"cmd/addr2line":                        toTool,
+	"cmd/api":                              toTool,
+	"cmd/cgo":                              toTool,
+	"cmd/fix":                              toTool,
+	"cmd/link":                             toTool,
+	"cmd/nm":                               toTool,
+	"cmd/objdump":                          toTool,
+	"cmd/pack":                             toTool,
+	"cmd/yacc":                             toTool,
+	"code.google.com/p/go.tools/cmd/cover": toTool,
+	"code.google.com/p/go.tools/cmd/godoc": toBin,
+	"code.google.com/p/go.tools/cmd/vet":   toTool,
+}
+
+// expandScanner expands a scanner.List error into all the errors in the list.
+// The default Error method only shows the first error.
+func expandScanner(err error) error {
+	// Look for parser errors.
+	if err, ok := err.(scanner.ErrorList); ok {
+		// Prepare error with \n before each message.
+		// When printed in something like context: %v
+		// this will put the leading file positions each on
+		// its own line.  It will also show all the errors
+		// instead of just the first, as err.Error does.
+		var buf bytes.Buffer
+		for _, e := range err {
+			e.Pos.Filename = shortPath(e.Pos.Filename)
+			buf.WriteString("\n")
+			buf.WriteString(e.Error())
+		}
+		return errors.New(buf.String())
+	}
+	return err
+}
+
+var raceExclude = map[string]bool{
+	"runtime/race": true,
+	"runtime/cgo":  true,
+	"cmd/cgo":      true,
+	"syscall":      true,
+	"errors":       true,
+}
+
+var cgoExclude = map[string]bool{
+	"runtime/cgo": true,
+}
+
+var cgoSyscallExclude = map[string]bool{
+	"runtime/cgo":  true,
+	"runtime/race": true,
+}
+
+// load populates p using information from bp, err, which should
+// be the result of calling build.Context.Import.
+func (p *Package) load(stk *importStack, bp *build.Package, err error) *Package {
+	p.copyBuild(bp)
+
+	// The localPrefix is the path we interpret ./ imports relative to.
+	// Synthesized main packages sometimes override this.
+	p.localPrefix = dirToImportPath(p.Dir)
+
+	if err != nil {
+		p.Incomplete = true
+		err = expandScanner(err)
+		p.Error = &PackageError{
+			ImportStack: stk.copy(),
+			Err:         err.Error(),
+		}
+		return p
+	}
+
+	if p.Name == "main" {
+		_, elem := filepath.Split(p.Dir)
+		full := buildContext.GOOS + "_" + buildContext.GOARCH + "/" + elem
+		if buildContext.GOOS != toolGOOS || buildContext.GOARCH != toolGOARCH {
+			// Install cross-compiled binaries to subdirectories of bin.
+			elem = full
+		}
+		if p.build.BinDir != gobin && goTools[p.ImportPath] == toBin {
+			// Override BinDir.
+			// This is from a subrepo but installs to $GOROOT/bin
+			// by default anyway (like godoc).
+			p.target = filepath.Join(gorootBin, elem)
+		} else if p.build.BinDir != "" {
+			// Install to GOBIN or bin of GOPATH entry.
+			p.target = filepath.Join(p.build.BinDir, elem)
+		}
+		if goTools[p.ImportPath] == toTool {
+			// This is for 'go tool'.
+			// Override all the usual logic and force it into the tool directory.
+			p.target = filepath.Join(gorootPkg, "tool", full)
+		}
+		if p.target != "" && buildContext.GOOS == "windows" {
+			p.target += ".exe"
+		}
+	} else if p.local {
+		// Local import turned into absolute path.
+		// No permanent install target.
+		p.target = ""
+	} else {
+		p.target = p.build.PkgObj
+	}
+
+	importPaths := p.Imports
+	// Packages that use cgo import runtime/cgo implicitly.
+	// Packages that use cgo also import syscall implicitly,
+	// to wrap errno.
+	// Exclude certain packages to avoid circular dependencies.
+	if len(p.CgoFiles) > 0 && (!p.Standard || !cgoExclude[p.ImportPath]) {
+		importPaths = append(importPaths, "runtime/cgo")
+	}
+	if len(p.CgoFiles) > 0 && (!p.Standard || !cgoSyscallExclude[p.ImportPath]) {
+		importPaths = append(importPaths, "syscall")
+	}
+	// Everything depends on runtime, except runtime and unsafe.
+	if !p.Standard || (p.ImportPath != "runtime" && p.ImportPath != "unsafe") {
+		importPaths = append(importPaths, "runtime")
+		// When race detection enabled everything depends on runtime/race.
+		// Exclude certain packages to avoid circular dependencies.
+		if buildRace && (!p.Standard || !raceExclude[p.ImportPath]) {
+			importPaths = append(importPaths, "runtime/race")
+		}
+	}
+
+	// Build list of full paths to all Go files in the package,
+	// for use by commands like go fmt.
+	p.gofiles = stringList(p.GoFiles, p.CgoFiles, p.TestGoFiles, p.XTestGoFiles)
+	for i := range p.gofiles {
+		p.gofiles[i] = filepath.Join(p.Dir, p.gofiles[i])
+	}
+	sort.Strings(p.gofiles)
+
+	p.sfiles = stringList(p.SFiles)
+	for i := range p.sfiles {
+		p.sfiles[i] = filepath.Join(p.Dir, p.sfiles[i])
+	}
+	sort.Strings(p.sfiles)
+
+	p.allgofiles = stringList(p.IgnoredGoFiles)
+	for i := range p.allgofiles {
+		p.allgofiles[i] = filepath.Join(p.Dir, p.allgofiles[i])
+	}
+	p.allgofiles = append(p.allgofiles, p.gofiles...)
+	sort.Strings(p.allgofiles)
+
+	// Check for case-insensitive collision of input files.
+	// To avoid problems on case-insensitive files, we reject any package
+	// where two different input files have equal names under a case-insensitive
+	// comparison.
+	f1, f2 := foldDup(stringList(
+		p.GoFiles,
+		p.CgoFiles,
+		p.IgnoredGoFiles,
+		p.CFiles,
+		p.CXXFiles,
+		p.MFiles,
+		p.HFiles,
+		p.SFiles,
+		p.SysoFiles,
+		p.SwigFiles,
+		p.SwigCXXFiles,
+		p.TestGoFiles,
+		p.XTestGoFiles,
+	))
+	if f1 != "" {
+		p.Error = &PackageError{
+			ImportStack: stk.copy(),
+			Err:         fmt.Sprintf("case-insensitive file name collision: %q and %q", f1, f2),
+		}
+		return p
+	}
+
+	// Build list of imported packages and full dependency list.
+	imports := make([]*Package, 0, len(p.Imports))
+	deps := make(map[string]bool)
+	for i, path := range importPaths {
+		if path == "C" {
+			continue
+		}
+		p1 := loadImport(path, p.Dir, stk, p.build.ImportPos[path])
+		if !reqPkgSrc && p1.Root == "" {
+			continue
+		}
+		if p1.local {
+			if !p.local && p.Error == nil {
+				p.Error = &PackageError{
+					ImportStack: stk.copy(),
+					Err:         fmt.Sprintf("local import %q in non-local package", path),
+				}
+				pos := p.build.ImportPos[path]
+				if len(pos) > 0 {
+					p.Error.Pos = pos[0].String()
+				}
+			}
+			path = p1.ImportPath
+			importPaths[i] = path
+		}
+		deps[path] = true
+		imports = append(imports, p1)
+		for _, dep := range p1.Deps {
+			deps[dep] = true
+		}
+		if p1.Incomplete {
+			p.Incomplete = true
+		}
+	}
+	p.imports = imports
+
+	p.Deps = make([]string, 0, len(deps))
+	for dep := range deps {
+		p.Deps = append(p.Deps, dep)
+	}
+	sort.Strings(p.Deps)
+	for _, dep := range p.Deps {
+		p1 := packageCache[dep]
+		if p1 == nil {
+			panic("impossible: missing entry in package cache for " + dep + " imported by " + p.ImportPath)
+		}
+		p.deps = append(p.deps, p1)
+		if p1.Error != nil {
+			p.DepsErrors = append(p.DepsErrors, p1.Error)
+		}
+	}
+
+	// unsafe is a fake package.
+	if p.Standard && (p.ImportPath == "unsafe" || buildContext.Compiler == "gccgo") {
+		p.target = ""
+	}
+	p.Target = p.target
+
+	// In the absence of errors lower in the dependency tree,
+	// check for case-insensitive collisions of import paths.
+	if len(p.DepsErrors) == 0 {
+		dep1, dep2 := foldDup(p.Deps)
+		if dep1 != "" {
+			p.Error = &PackageError{
+				ImportStack: stk.copy(),
+				Err:         fmt.Sprintf("case-insensitive import collision: %q and %q", dep1, dep2),
+			}
+			return p
+		}
+	}
+
+	return p
+}
+
+// usesSwig reports whether the package needs to run SWIG.
+func (p *Package) usesSwig() bool {
+	return len(p.SwigFiles) > 0 || len(p.SwigCXXFiles) > 0
+}
+
+// usesCgo reports whether the package needs to run cgo
+func (p *Package) usesCgo() bool {
+	return len(p.CgoFiles) > 0
+}
+
+// packageList returns the list of packages in the dag rooted at roots
+// as visited in a depth-first post-order traversal.
+func packageList(roots []*Package) []*Package {
+	seen := map[*Package]bool{}
+	all := []*Package{}
+	var walk func(*Package)
+	walk = func(p *Package) {
+		if seen[p] {
+			return
+		}
+		seen[p] = true
+		for _, p1 := range p.imports {
+			walk(p1)
+		}
+		all = append(all, p)
+	}
+	for _, root := range roots {
+		walk(root)
+	}
+	return all
+}
+
+// computeStale computes the Stale flag in the package dag that starts
+// at the named pkgs (command-line arguments).
+func computeStale(pkgs ...*Package) {
+	topRoot := map[string]bool{}
+	for _, p := range pkgs {
+		topRoot[p.Root] = true
+	}
+
+	for _, p := range packageList(pkgs) {
+		p.Stale = isStale(p, topRoot)
+	}
+}
+
+// isStale reports whether package p needs to be rebuilt.
+func isStale(p *Package, topRoot map[string]bool) bool {
+	if p.Standard && (p.ImportPath == "unsafe" || buildContext.Compiler == "gccgo") {
+		// fake, builtin package
+		return false
+	}
+	if p.Error != nil {
+		return true
+	}
+
+	// A package without Go sources means we only found
+	// the installed .a file.  Since we don't know how to rebuild
+	// it, it can't be stale, even if -a is set.  This enables binary-only
+	// distributions of Go packages, although such binaries are
+	// only useful with the specific version of the toolchain that
+	// created them.
+	if len(p.gofiles) == 0 && !p.usesSwig() {
+		return false
+	}
+
+	if buildA || p.target == "" || p.Stale {
+		return true
+	}
+
+	// Package is stale if completely unbuilt.
+	var built time.Time
+	if fi, err := os.Stat(p.target); err == nil {
+		built = fi.ModTime()
+	}
+	if built.IsZero() {
+		return true
+	}
+
+	olderThan := func(file string) bool {
+		fi, err := os.Stat(file)
+		return err != nil || fi.ModTime().After(built)
+	}
+
+	// Package is stale if a dependency is, or if a dependency is newer.
+	for _, p1 := range p.deps {
+		if p1.Stale || p1.target != "" && olderThan(p1.target) {
+			return true
+		}
+	}
+
+	// As a courtesy to developers installing new versions of the compiler
+	// frequently, define that packages are stale if they are
+	// older than the compiler, and commands if they are older than
+	// the linker.  This heuristic will not work if the binaries are
+	// back-dated, as some binary distributions may do, but it does handle
+	// a very common case.
+	// See issue 3036.
+	// Assume code in $GOROOT is up to date, since it may not be writeable.
+	// See issue 4106.
+	if p.Root != goroot {
+		if olderThan(buildToolchain.compiler()) {
+			return true
+		}
+		if p.build.IsCommand() && olderThan(buildToolchain.linker()) {
+			return true
+		}
+	}
+
+	// Have installed copy, probably built using current compilers,
+	// and built after its imported packages.  The only reason now
+	// that we'd have to rebuild it is if the sources were newer than
+	// the package.   If a package p is not in the same tree as any
+	// package named on the command-line, assume it is up-to-date
+	// no matter what the modification times on the source files indicate.
+	// This avoids rebuilding $GOROOT packages when people are
+	// working outside the Go root, and it effectively makes each tree
+	// listed in $GOPATH a separate compilation world.
+	// See issue 3149.
+	if p.Root != "" && !topRoot[p.Root] {
+		return false
+	}
+
+	srcs := stringList(p.GoFiles, p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.SFiles, p.CgoFiles, p.SysoFiles, p.SwigFiles, p.SwigCXXFiles)
+	for _, src := range srcs {
+		if olderThan(filepath.Join(p.Dir, src)) {
+			return true
+		}
+	}
+
+	return false
+}
+
+var cwd, _ = os.Getwd()
+
+var cmdCache = map[string]*Package{}
+
+// loadPackage is like loadImport but is used for command-line arguments,
+// not for paths found in import statements.  In addition to ordinary import paths,
+// loadPackage accepts pseudo-paths beginning with cmd/ to denote commands
+// in the Go command directory, as well as paths to those directories.
+func loadPackage(arg string, stk *importStack) *Package {
+	if build.IsLocalImport(arg) {
+		dir := arg
+		if !filepath.IsAbs(dir) {
+			if abs, err := filepath.Abs(dir); err == nil {
+				// interpret relative to current directory
+				dir = abs
+			}
+		}
+		if sub, ok := hasSubdir(gorootSrc, dir); ok && strings.HasPrefix(sub, "cmd/") && !strings.Contains(sub[4:], "/") {
+			arg = sub
+		}
+	}
+	if strings.HasPrefix(arg, "cmd/") {
+		if p := cmdCache[arg]; p != nil {
+			return p
+		}
+		stk.push(arg)
+		defer stk.pop()
+
+		if strings.Contains(arg[4:], "/") {
+			p := &Package{
+				Error: &PackageError{
+					ImportStack: stk.copy(),
+					Err:         fmt.Sprintf("invalid import path: cmd/... is reserved for Go commands"),
+					hard:        true,
+				},
+			}
+			return p
+		}
+
+		bp, err := buildContext.ImportDir(filepath.Join(gorootSrc, arg), 0)
+		bp.ImportPath = arg
+		bp.Goroot = true
+		bp.BinDir = gorootBin
+		if gobin != "" {
+			bp.BinDir = gobin
+		}
+		bp.Root = goroot
+		bp.SrcRoot = gorootSrc
+		p := new(Package)
+		cmdCache[arg] = p
+		p.load(stk, bp, err)
+		if p.Error == nil && p.Name != "main" {
+			p.Error = &PackageError{
+				ImportStack: stk.copy(),
+				Err:         fmt.Sprintf("expected package main but found package %s in %s", p.Name, p.Dir),
+			}
+		}
+		return p
+	}
+
+	// Wasn't a command; must be a package.
+	// If it is a local import path but names a standard package,
+	// we treat it as if the user specified the standard package.
+	// This lets you run go test ./ioutil in package io and be
+	// referring to io/ioutil rather than a hypothetical import of
+	// "./ioutil".
+	if build.IsLocalImport(arg) {
+		bp, _ := buildContext.ImportDir(filepath.Join(cwd, arg), build.FindOnly)
+		if bp.ImportPath != "" && bp.ImportPath != "." {
+			arg = bp.ImportPath
+		}
+	}
+
+	return loadImport(arg, cwd, stk, nil)
+}
+
+// packages returns the packages named by the
+// command line arguments 'args'.  If a named package
+// cannot be loaded at all (for example, if the directory does not exist),
+// then packages prints an error and does not include that
+// package in the results.  However, if errors occur trying
+// to load dependencies of a named package, the named
+// package is still returned, with p.Incomplete = true
+// and details in p.DepsErrors.
+func packages(args []string) []*Package {
+	var pkgs []*Package
+	for _, pkg := range packagesAndErrors(args) {
+		if pkg.Error != nil {
+			errorf("can't load package: %s", pkg.Error)
+			continue
+		}
+		pkgs = append(pkgs, pkg)
+	}
+	return pkgs
+}
+
+// packagesAndErrors is like 'packages' but returns a
+// *Package for every argument, even the ones that
+// cannot be loaded at all.
+// The packages that fail to load will have p.Error != nil.
+func packagesAndErrors(args []string) []*Package {
+	if len(args) > 0 && strings.HasSuffix(args[0], ".go") {
+		return []*Package{goFilesPackage(args)}
+	}
+
+	args = importPaths(args)
+	var pkgs []*Package
+	var stk importStack
+	var set = make(map[string]bool)
+
+	for _, arg := range args {
+		if !set[arg] {
+			pkgs = append(pkgs, loadPackage(arg, &stk))
+			set[arg] = true
+		}
+	}
+	computeStale(pkgs...)
+
+	return pkgs
+}
+
+// packagesForBuild is like 'packages' but fails if any of
+// the packages or their dependencies have errors
+// (cannot be built).
+func packagesForBuild(args []string) []*Package {
+	pkgs := packagesAndErrors(args)
+	printed := map[*PackageError]bool{}
+	for _, pkg := range pkgs {
+		if pkg.Error != nil {
+			errorf("can't load package: %s", pkg.Error)
+		}
+		for _, err := range pkg.DepsErrors {
+			// Since these are errors in dependencies,
+			// the same error might show up multiple times,
+			// once in each package that depends on it.
+			// Only print each once.
+			if !printed[err] {
+				printed[err] = true
+				errorf("%s", err)
+			}
+		}
+	}
+	exitIfErrors()
+	return pkgs
+}
+
+// hasSubdir reports whether dir is a subdirectory of
+// (possibly multiple levels below) root.
+// If so, it sets rel to the path fragment that must be
+// appended to root to reach dir.
+func hasSubdir(root, dir string) (rel string, ok bool) {
+	if p, err := filepath.EvalSymlinks(root); err == nil {
+		root = p
+	}
+	if p, err := filepath.EvalSymlinks(dir); err == nil {
+		dir = p
+	}
+	const sep = string(filepath.Separator)
+	root = filepath.Clean(root)
+	if !strings.HasSuffix(root, sep) {
+		root += sep
+	}
+	dir = filepath.Clean(dir)
+	if !strings.HasPrefix(dir, root) {
+		return "", false
+	}
+	return filepath.ToSlash(dir[len(root):]), true
+}

libgo/go/cmd/go/pkg_test.go

@@ -0,0 +1,73 @@
+// Copyright 2014 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.
+
+package main
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+var foldDupTests = []struct {
+	list   []string
+	f1, f2 string
+}{
+	{stringList("math/rand", "math/big"), "", ""},
+	{stringList("math", "strings"), "", ""},
+	{stringList("strings"), "", ""},
+	{stringList("strings", "strings"), "strings", "strings"},
+	{stringList("Rand", "rand", "math", "math/rand", "math/Rand"), "Rand", "rand"},
+}
+
+func TestFoldDup(t *testing.T) {
+	for _, tt := range foldDupTests {
+		f1, f2 := foldDup(tt.list)
+		if f1 != tt.f1 || f2 != tt.f2 {
+			t.Errorf("foldDup(%q) = %q, %q, want %q, %q", tt.list, f1, f2, tt.f1, tt.f2)
+		}
+	}
+}
+
+var parseMetaGoImportsTests = []struct {
+	in  string
+	out []metaImport
+}{
+	{
+		`<meta name="go-import" content="foo/bar git https://github.com/rsc/foo/bar">`,
+		[]metaImport{{"foo/bar", "git", "https://github.com/rsc/foo/bar"}},
+	},
+	{
+		`<meta name="go-import" content="foo/bar git https://github.com/rsc/foo/bar">
+		<meta name="go-import" content="baz/quux git http://github.com/rsc/baz/quux">`,
+		[]metaImport{
+			{"foo/bar", "git", "https://github.com/rsc/foo/bar"},
+			{"baz/quux", "git", "http://github.com/rsc/baz/quux"},
+		},
+	},
+	{
+		`<head>
+		<meta name="go-import" content="foo/bar git https://github.com/rsc/foo/bar">
+		</head>`,
+		[]metaImport{{"foo/bar", "git", "https://github.com/rsc/foo/bar"}},
+	},
+	{
+		`<meta name="go-import" content="foo/bar git https://github.com/rsc/foo/bar">
+		<body>`,
+		[]metaImport{{"foo/bar", "git", "https://github.com/rsc/foo/bar"}},
+	},
+}
+
+func TestParseMetaGoImports(t *testing.T) {
+	for i, tt := range parseMetaGoImportsTests {
+		out, err := parseMetaGoImports(strings.NewReader(tt.in))
+		if err != nil {
+			t.Errorf("test#%d: %v", i, err)
+			continue
+		}
+		if !reflect.DeepEqual(out, tt.out) {
+			t.Errorf("test#%d:\n\thave %q\n\twant %q", i, out, tt.out)
+		}
+	}
+}

libgo/go/cmd/go/run.go

@@ -0,0 +1,143 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"runtime"
+	"strings"
+)
+
+var execCmd []string // -exec flag, for run and test
+
+func findExecCmd() []string {
+	if execCmd != nil {
+		return execCmd
+	}
+	execCmd = []string{} // avoid work the second time
+	if goos == runtime.GOOS && goarch == runtime.GOARCH {
+		return execCmd
+	}
+	path, err := exec.LookPath(fmt.Sprintf("go_%s_%s_exec", goos, goarch))
+	if err == nil {
+		execCmd = []string{path}
+	}
+	return execCmd
+}
+
+var cmdRun = &Command{
+	UsageLine: "run [build flags] [-exec xprog] gofiles... [arguments...]",
+	Short:     "compile and run Go program",
+	Long: `
+Run compiles and runs the main package comprising the named Go source files.
+A Go source file is defined to be a file ending in a literal ".go" suffix.
+
+By default, 'go run' runs the compiled binary directly: 'a.out arguments...'.
+If the -exec flag is given, 'go run' invokes the binary using xprog: 'xprog a.out arguments...'.
+If the -exec flag is not given, GOOS or GOARCH is different from the system
+default, and a program named go_$GOOS_$GOARCH_exec can be found
+on the current search path, 'go run' invokes the binary using that program,
+for example 'go_nacl_386_exec a.out arguments...'. This allows execution of
+cross-compiled programs when a simulator or other execution method is
+available.
+
+For more about build flags, see 'go help build'.
+
+See also: go build.
+	`,
+}
+
+func init() {
+	cmdRun.Run = runRun // break init loop
+
+	addBuildFlags(cmdRun)
+	cmdRun.Flag.Var((*stringsFlag)(&execCmd), "exec", "")
+}
+
+func printStderr(args ...interface{}) (int, error) {
+	return fmt.Fprint(os.Stderr, args...)
+}
+
+func runRun(cmd *Command, args []string) {
+	raceInit()
+	var b builder
+	b.init()
+	b.print = printStderr
+	i := 0
+	for i < len(args) && strings.HasSuffix(args[i], ".go") {
+		i++
+	}
+	files, cmdArgs := args[:i], args[i:]
+	if len(files) == 0 {
+		fatalf("go run: no go files listed")
+	}
+	for _, file := range files {
+		if strings.HasSuffix(file, "_test.go") {
+			// goFilesPackage is going to assign this to TestGoFiles.
+			// Reject since it won't be part of the build.
+			fatalf("go run: cannot run *_test.go files (%s)", file)
+		}
+	}
+	p := goFilesPackage(files)
+	if p.Error != nil {
+		fatalf("%s", p.Error)
+	}
+	p.omitDWARF = true
+	for _, err := range p.DepsErrors {
+		errorf("%s", err)
+	}
+	exitIfErrors()
+	if p.Name != "main" {
+		fatalf("go run: cannot run non-main package")
+	}
+	p.target = "" // must build - not up to date
+	var src string
+	if len(p.GoFiles) > 0 {
+		src = p.GoFiles[0]
+	} else if len(p.CgoFiles) > 0 {
+		src = p.CgoFiles[0]
+	} else {
+		// this case could only happen if the provided source uses cgo
+		// while cgo is disabled.
+		hint := ""
+		if !buildContext.CgoEnabled {
+			hint = " (cgo is disabled)"
+		}
+		fatalf("go run: no suitable source files%s", hint)
+	}
+	p.exeName = src[:len(src)-len(".go")] // name temporary executable for first go file
+	a1 := b.action(modeBuild, modeBuild, p)
+	a := &action{f: (*builder).runProgram, args: cmdArgs, deps: []*action{a1}}
+	b.do(a)
+}
+
+// runProgram is the action for running a binary that has already
+// been compiled.  We ignore exit status.
+func (b *builder) runProgram(a *action) error {
+	cmdline := stringList(findExecCmd(), a.deps[0].target, a.args)
+	if buildN || buildX {
+		b.showcmd("", "%s", strings.Join(cmdline, " "))
+		if buildN {
+			return nil
+		}
+	}
+
+	runStdin(cmdline)
+	return nil
+}
+
+// runStdin is like run, but connects Stdin.
+func runStdin(cmdline []string) {
+	cmd := exec.Command(cmdline[0], cmdline[1:]...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	startSigHandlers()
+	if err := cmd.Run(); err != nil {
+		errorf("%v", err)
+	}
+}

libgo/go/cmd/go/script

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+x() {
+	echo '--- ' "$@"
+	"$@"
+	echo '---'
+	echo
+}
+
+x go help
+x go help build
+x go help clean
+x go help install
+x go help fix
+x go help fmt
+x go help get
+x go help list
+x go help test
+x go help version
+x go help vet
+x go help gopath
+x go help importpath
+x go help remote

libgo/go/cmd/go/script.txt

@@ -0,0 +1,352 @@
+---  go help
+usage: go command [arguments]
+
+go manages Go source code.
+
+The commands are:
+
+    build       compile and install packages and dependencies
+    clean       remove intermediate objects
+    fix         run gofix on packages
+    fmt         run gofmt -w on packages
+    get         download and install packages and dependencies
+    install     install packages and dependencies
+    list        list packages
+    test        test packages
+    version     print Go version
+    vet         run govet on packages
+
+Use "go help [command]" for more information about a command.
+
+Additional help topics:
+
+    gopath      GOPATH environment variable
+    importpath  description of import paths
+    remote      remote import path syntax
+
+Use "go help [topic]" for more information about that topic.
+
+---
+
+---  go help build
+usage: go build [-n] [-v] [importpath...]
+
+Build compiles the packages named by the import paths,
+along with their dependencies, but it does not install the results.
+
+The -n flag prints the commands but does not run them.
+The -v flag prints the commands.
+
+For more about import paths, see 'go help importpath'.
+
+See also: go install, go get, go clean.
+---
+
+---  go help clean
+usage: go clean [-nuke] [importpath...]
+
+Clean removes intermediate object files generated during
+the compilation of the packages named by the import paths,
+but by default it does not remove the installed package binaries.
+
+The -nuke flag causes clean to remove the installed package binaries too.
+
+TODO: Clean does not clean dependencies of the packages.
+
+For more about import paths, see 'go help importpath'.
+---
+
+---  go help install
+usage: go install [-n] [-v] [importpath...]
+
+Install compiles and installs the packages named by the import paths,
+along with their dependencies.
+
+The -n flag prints the commands but does not run them.
+The -v flag prints the commands.
+
+For more about import paths, see 'go help importpath'.
+
+See also: go build, go get, go clean.
+---
+
+---  go help fix
+usage: go fix [importpath...]
+
+Fix runs the gofix command on the packages named by the import paths.
+
+For more about gofix, see 'godoc gofix'.
+For more about import paths, see 'go help importpath'.
+
+To run gofix with specific options, run gofix itself.
+
+See also: go fmt, go vet.
+---
+
+---  go help fmt
+usage: go fmt [importpath...]
+
+Fmt runs the command 'gofmt -w' on the packages named by the import paths.
+
+For more about gofmt, see 'godoc gofmt'.
+For more about import paths, see 'go help importpath'.
+
+To run gofmt with specific options, run gofmt itself.
+
+See also: go fix, go vet.
+---
+
+---  go help get
+usage: go get [importpath...]
+
+Get downloads and installs the packages named by the import paths,
+along with their dependencies.
+
+After downloading the code, 'go get' looks for a tag beginning
+with "go." that corresponds to the local Go version.
+For Go "release.r58" it looks for a tag named "go.r58".
+For "weekly.2011-06-03" it looks for "go.weekly.2011-06-03".
+If the specific "go.X" tag is not found, it uses the latest earlier
+version it can find.  Otherwise, it uses the default version for
+the version control system: HEAD for git, tip for Mercurial,
+and so on.
+
+TODO: Explain versions better.
+
+For more about import paths, see 'go help importpath'.
+
+For more about how 'go get' finds source code to
+download, see 'go help remote'.
+
+See also: go build, go install, go clean.
+---
+
+---  go help list
+usage: go list [-f format] [-json] [importpath...]
+
+List lists the packages named by the import paths.
+
+The default output shows the package name and file system location:
+
+    books /home/you/src/google-api-go-client.googlecode.com/hg/books/v1
+    oauth /home/you/src/goauth2.googlecode.com/hg/oauth
+    sqlite /home/you/src/gosqlite.googlecode.com/hg/sqlite
+
+The -f flag specifies an alternate format for the list,
+using the syntax of package template.  The default output
+is equivalent to -f '{{.Name}} {{.Dir}}'  The struct
+being passed to the template is:
+
+    type Package struct {
+        Name string         // package name
+        Doc string          // package documentation string
+        GoFiles []string    // names of Go source files in package
+        ImportPath string   // import path denoting package
+        Imports []string    // import paths used by this package
+        Deps []string       // all (recursively) imported dependencies
+        Dir string          // directory containing package sources
+        Version string      // version of installed package
+    }
+
+The -json flag causes the package data to be printed in JSON format.
+
+For more about import paths, see 'go help importpath'.
+---
+
+---  go help test
+usage: go test [importpath...]
+
+Test runs gotest to test the packages named by the import paths.
+It prints a summary of the test results in the format:
+
+	test archive/tar
+	FAIL archive/zip
+	test compress/gzip
+	...
+
+followed by gotest output for each failed package.
+
+For more about import paths, see 'go help importpath'.
+
+See also: go build, go compile, go vet.
+---
+
+---  go help version
+usage: go version
+
+Version prints the Go version, as reported by runtime.Version.
+---
+
+---  go help vet
+usage: go vet [importpath...]
+
+Vet runs the govet command on the packages named by the import paths.
+
+For more about govet, see 'godoc govet'.
+For more about import paths, see 'go help importpath'.
+
+To run govet with specific options, run govet itself.
+
+See also: go fmt, go fix.
+---
+
+---  go help gopath
+The GOPATH environment variable lists places to look for Go code.
+On Unix, the value is a colon-separated string.
+On Windows, the value is a semicolon-separated string.
+On Plan 9, the value is a list.
+
+GOPATH must be set to build and install packages outside the
+standard Go tree.
+
+Each directory listed in GOPATH must have a prescribed structure:
+
+The src/ directory holds source code.  The path below 'src'
+determines the import path or executable name.
+
+The pkg/ directory holds installed package objects.
+As in the Go tree, each target operating system and
+architecture pair has its own subdirectory of pkg
+(pkg/GOOS_GOARCH).
+
+If DIR is a directory listed in the GOPATH, a package with
+source in DIR/src/foo/bar can be imported as "foo/bar" and
+has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a".
+
+The bin/ directory holds compiled commands.
+Each command is named for its source directory, but only
+the final element, not the entire path.  That is, the
+command with source in DIR/src/foo/quux is installed into
+DIR/bin/quux, not DIR/bin/foo/quux.  The foo/ is stripped
+so that you can add DIR/bin to your PATH to get at the
+installed commands.
+
+Here's an example directory layout:
+
+    GOPATH=/home/user/gocode
+
+    /home/user/gocode/
+        src/
+            foo/
+                bar/               (go code in package bar)
+                    x.go
+                quux/              (go code in package main)
+                    y.go
+        bin/
+            quux                   (installed command)
+		pkg/
+		    linux_amd64/
+		        foo/
+		            bar.a          (installed package object)
+
+Go searches each directory listed in GOPATH to find source code,
+but new packages are always downloaded into the first directory 
+in the list.
+---
+
+---  go help importpath
+Many commands apply to a set of packages named by import paths:
+
+	go action [importpath...]
+
+An import path that is a rooted path or that begins with
+a . or .. element is interpreted as a file system path and
+denotes the package in that directory.
+
+Otherwise, the import path P denotes the package found in
+the directory DIR/src/P for some DIR listed in the GOPATH
+environment variable (see 'go help gopath'). 
+
+If no import paths are given, the action applies to the
+package in the current directory.
+
+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.
+
+An import path can also name a package to be downloaded from
+a remote repository.  Run 'go help remote' for details.
+
+Every package in a program must have a unique import path.
+By convention, this is arranged by starting each path with a
+unique prefix that belongs to you.  For example, paths used
+internally at Google all begin with 'google', and paths
+denoting remote repositories begin with the path to the code,
+such as 'project.googlecode.com/'.
+---
+
+---  go help remote
+An import path (see 'go help importpath') denotes a package
+stored in the local file system.  Certain import paths also
+describe how to obtain the source code for the package using
+a revision control system.
+
+A few common code hosting sites have special syntax:
+
+	BitBucket (Mercurial)
+
+		import "bitbucket.org/user/project"
+		import "bitbucket.org/user/project/sub/directory"
+
+	GitHub (Git)
+
+		import "github.com/user/project"
+		import "github.com/user/project/sub/directory"
+
+	Google Code Project Hosting (Git, Mercurial, Subversion)
+
+		import "project.googlecode.com/git"
+		import "project.googlecode.com/git/sub/directory"
+
+		import "project.googlecode.com/hg"
+		import "project.googlecode.com/hg/sub/directory"
+
+		import "project.googlecode.com/svn/trunk"
+		import "project.googlecode.com/svn/trunk/sub/directory"
+
+	Launchpad (Bazaar)
+
+		import "launchpad.net/project"
+		import "launchpad.net/project/series"
+		import "launchpad.net/project/series/sub/directory"
+
+		import "launchpad.net/~user/project/branch"
+		import "launchpad.net/~user/project/branch/sub/directory"
+
+For code hosted on other servers, an import path of the form
+
+	repository.vcs/path
+
+specifies the given repository, with or without the .vcs suffix,
+using the named version control system, and then the path inside
+that repository.  The supported version control systems are:
+
+	Bazaar      .bzr
+	Git         .git
+	Mercurial   .hg
+	Subversion  .svn
+
+For example,
+
+	import "example.org/user/foo.hg"
+
+denotes the root directory of the Mercurial repository at
+example.org/user/foo or foo.hg, and
+
+	import "example.org/repo.git/foo/bar"
+
+denotes the foo/bar directory of the Git repository at
+example.com/repo or repo.git.
+
+When a version control system supports multiple protocols,
+each is tried in turn when downloading.  For example, a Git
+download tries git://, then https://, then http://.
+
+New downloaded packages are written to the first directory
+listed in the GOPATH environment variable (see 'go help gopath').
+
+The go command attempts to download the version of the
+package appropriate for the Go release being used.
+Run 'go help install' for more.
+---
+

libgo/go/cmd/go/signal.go

@@ -0,0 +1,31 @@
+// Copyright 2012 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.
+
+package main
+
+import (
+	"os"
+	"os/signal"
+	"sync"
+)
+
+// interrupted is closed, if go process is interrupted.
+var interrupted = make(chan struct{})
+
+// processSignals setups signal handler.
+func processSignals() {
+	sig := make(chan os.Signal)
+	signal.Notify(sig, signalsToIgnore...)
+	go func() {
+		<-sig
+		close(interrupted)
+	}()
+}
+
+var onceProcessSignals sync.Once
+
+// startSigHandlers start signal handlers.
+func startSigHandlers() {
+	onceProcessSignals.Do(processSignals)
+}

libgo/go/cmd/go/signal_notunix.go

@@ -0,0 +1,17 @@
+// Copyright 2012 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.
+
+// +build plan9 windows
+
+package main
+
+import (
+	"os"
+)
+
+var signalsToIgnore = []os.Signal{os.Interrupt}
+
+// signalTrace is the signal to send to make a Go program
+// crash with a stack trace.
+var signalTrace os.Signal = nil

libgo/go/cmd/go/signal_unix.go

@@ -0,0 +1,18 @@
+// Copyright 2012 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.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+
+package main
+
+import (
+	"os"
+	"syscall"
+)
+
+var signalsToIgnore = []os.Signal{os.Interrupt, syscall.SIGQUIT}
+
+// signalTrace is the signal to send to make a Go program
+// crash with a stack trace.
+var signalTrace os.Signal = syscall.SIGQUIT

libgo/go/cmd/go/tag_test.go

@@ -0,0 +1,100 @@
+// Copyright 2011 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.
+
+package main
+
+import "testing"
+
+var selectTagTestTags = []string{
+	"go.r58",
+	"go.r58.1",
+	"go.r59",
+	"go.r59.1",
+	"go.r61",
+	"go.r61.1",
+	"go.weekly.2010-01-02",
+	"go.weekly.2011-10-12",
+	"go.weekly.2011-10-12.1",
+	"go.weekly.2011-10-14",
+	"go.weekly.2011-11-01",
+	"go1",
+	"go1.0.1",
+	"go1.999",
+	"go1.9.2",
+	"go5",
+
+	// these should be ignored:
+	"release.r59",
+	"release.r59.1",
+	"release",
+	"weekly.2011-10-12",
+	"weekly.2011-10-12.1",
+	"weekly",
+	"foo",
+	"bar",
+	"go.f00",
+	"go!r60",
+	"go.1999-01-01",
+	"go.2x",
+	"go.20000000000000",
+	"go.2.",
+	"go.2.0",
+	"go2x",
+	"go20000000000000",
+	"go2.",
+	"go2.0",
+}
+
+var selectTagTests = []struct {
+	version  string
+	selected string
+}{
+	/*
+		{"release.r57", ""},
+		{"release.r58.2", "go.r58.1"},
+		{"release.r59", "go.r59"},
+		{"release.r59.1", "go.r59.1"},
+		{"release.r60", "go.r59.1"},
+		{"release.r60.1", "go.r59.1"},
+		{"release.r61", "go.r61"},
+		{"release.r66", "go.r61.1"},
+		{"weekly.2010-01-01", ""},
+		{"weekly.2010-01-02", "go.weekly.2010-01-02"},
+		{"weekly.2010-01-02.1", "go.weekly.2010-01-02"},
+		{"weekly.2010-01-03", "go.weekly.2010-01-02"},
+		{"weekly.2011-10-12", "go.weekly.2011-10-12"},
+		{"weekly.2011-10-12.1", "go.weekly.2011-10-12.1"},
+		{"weekly.2011-10-13", "go.weekly.2011-10-12.1"},
+		{"weekly.2011-10-14", "go.weekly.2011-10-14"},
+		{"weekly.2011-10-14.1", "go.weekly.2011-10-14"},
+		{"weekly.2011-11-01", "go.weekly.2011-11-01"},
+		{"weekly.2014-01-01", "go.weekly.2011-11-01"},
+		{"weekly.3000-01-01", "go.weekly.2011-11-01"},
+		{"go1", "go1"},
+		{"go1.1", "go1.0.1"},
+		{"go1.998", "go1.9.2"},
+		{"go1.1000", "go1.999"},
+		{"go6", "go5"},
+
+		// faulty versions:
+		{"release.f00", ""},
+		{"weekly.1999-01-01", ""},
+		{"junk", ""},
+		{"", ""},
+		{"go2x", ""},
+		{"go200000000000", ""},
+		{"go2.", ""},
+		{"go2.0", ""},
+	*/
+	{"anything", "go1"},
+}
+
+func TestSelectTag(t *testing.T) {
+	for _, c := range selectTagTests {
+		selected := selectTag(c.version, selectTagTestTags)
+		if selected != c.selected {
+			t.Errorf("selectTag(%q) = %q, want %q", c.version, selected, c.selected)
+		}
+	}
+}

libgo/go/cmd/go/test.bash

@@ -0,0 +1,820 @@
+#!/bin/bash
+# Copyright 2012 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.
+
+set -e
+go build -o testgo
+go() {
+	echo TEST ERROR: ran go, not testgo: go "$@" >&2
+	exit 2
+}
+
+started=false
+TEST() {
+	if $started; then
+		stop
+	fi
+	echo TEST: "$@"
+	started=true
+	ok=true
+}
+stop() {
+	if ! $started; then
+		echo TEST ERROR: stop missing start >&2
+		exit 2
+	fi
+	started=false
+	if $ok; then
+		echo PASS
+	else
+		echo FAIL
+		allok=false
+	fi
+}
+
+ok=true
+allok=true
+
+unset GOBIN
+unset GOPATH
+unset GOROOT
+
+TEST 'file:line in error messages'
+# Test that error messages have file:line information at beginning of
+# the line. Also test issue 4917: that the error is on stderr.
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+fn=$d/err.go
+echo "package main" > $fn
+echo 'import "bar"' >> $fn
+./testgo run $fn 2>$d/err.out || true
+if ! grep -q "^$fn:" $d/err.out; then
+	echo "missing file:line in error message"
+	cat $d/err.out
+	ok=false
+fi
+rm -r $d
+
+# Test local (./) imports.
+testlocal() {
+	local="$1"
+	TEST local imports $2 '(easy)'
+	./testgo build -o hello "testdata/$local/easy.go"
+	./hello >hello.out
+	if ! grep -q '^easysub\.Hello' hello.out; then
+		echo "testdata/$local/easy.go did not generate expected output"
+		cat hello.out
+		ok=false
+	fi
+	
+	TEST local imports $2 '(easysub)'
+	./testgo build -o hello "testdata/$local/easysub/main.go"
+	./hello >hello.out
+	if ! grep -q '^easysub\.Hello' hello.out; then
+		echo "testdata/$local/easysub/main.go did not generate expected output"
+		cat hello.out
+		ok=false
+	fi
+	
+	TEST local imports $2 '(hard)'
+	./testgo build -o hello "testdata/$local/hard.go"
+	./hello >hello.out
+	if ! grep -q '^sub\.Hello' hello.out || ! grep -q '^subsub\.Hello' hello.out ; then
+		echo "testdata/$local/hard.go did not generate expected output"
+		cat hello.out
+		ok=false
+	fi
+	
+	rm -f hello.out hello
+	
+	# Test that go install x.go fails.
+	TEST local imports $2 '(go install should fail)'
+	if ./testgo install "testdata/$local/easy.go" >/dev/null 2>&1; then
+		echo "go install testdata/$local/easy.go succeeded"
+		ok=false
+	fi
+}
+
+# Test local imports
+testlocal local ''
+
+# Test local imports again, with bad characters in the directory name.
+bad='#$%:, &()*;<=>?\^{}'
+rm -rf "testdata/$bad"
+cp -R testdata/local "testdata/$bad"
+testlocal "$bad" 'with bad characters in path'
+rm -rf "testdata/$bad"
+
+TEST error message for syntax error in test go file says FAIL
+export GOPATH=$(pwd)/testdata
+if ./testgo test syntaxerror 2>testdata/err; then
+	echo 'go test syntaxerror succeeded'
+	ok=false
+elif ! grep FAIL testdata/err >/dev/null; then
+	echo 'go test did not say FAIL:'
+	cat testdata/err
+	ok=false
+fi
+rm -f ./testdata/err
+unset GOPATH
+
+TEST wildcards do not look in useless directories
+export GOPATH=$(pwd)/testdata
+if ./testgo list ... >testdata/err 2>&1; then
+	echo "go list ... succeeded"
+	ok=false
+elif ! grep badpkg testdata/err >/dev/null; then
+	echo "go list ... failure does not mention badpkg"
+	cat testdata/err
+	ok=false
+elif ! ./testgo list m... >testdata/err 2>&1; then
+	echo "go list m... failed"
+	ok=false
+fi
+rm -rf ./testdata/err
+unset GOPATH
+
+# Test tests with relative imports.
+TEST relative imports '(go test)'
+if ! ./testgo test ./testdata/testimport; then
+	echo "go test ./testdata/testimport failed"
+	ok=false
+fi
+
+# Test installation with relative imports.
+TEST relative imports '(go test -i)'
+if ! ./testgo test -i ./testdata/testimport; then
+    echo "go test -i ./testdata/testimport failed"
+    ok=false
+fi
+
+# Test tests with relative imports in packages synthesized
+# from Go files named on the command line.
+TEST relative imports in command-line package
+if ! ./testgo test ./testdata/testimport/*.go; then
+	echo "go test ./testdata/testimport/*.go failed"
+	ok=false
+fi
+
+TEST version control error message includes correct directory
+export GOPATH=$(pwd)/testdata/shadow/root1
+if ./testgo get -u foo 2>testdata/err; then
+	echo "go get -u foo succeeded unexpectedly"
+	ok=false
+elif ! grep testdata/shadow/root1/src/foo testdata/err >/dev/null; then
+	echo "go get -u error does not mention shadow/root1/src/foo:"
+	cat testdata/err
+	ok=false
+fi
+unset GOPATH
+
+TEST go install fails with no buildable files
+export GOPATH=$(pwd)/testdata
+export CGO_ENABLED=0
+if ./testgo install cgotest 2>testdata/err; then
+	echo "go install cgotest succeeded unexpectedly"
+elif ! grep 'no buildable Go source files' testdata/err >/dev/null; then
+	echo "go install cgotest did not report 'no buildable Go source files'"
+	cat testdata/err
+	ok=false
+fi
+unset CGO_ENABLED
+unset GOPATH
+
+# Test that without $GOBIN set, binaries get installed
+# into the GOPATH bin directory.
+TEST install into GOPATH
+rm -rf testdata/bin
+if ! GOPATH=$(pwd)/testdata ./testgo install go-cmd-test; then
+	echo "go install go-cmd-test failed"
+	ok=false
+elif ! test -x testdata/bin/go-cmd-test; then
+	echo "go install go-cmd-test did not write to testdata/bin/go-cmd-test"
+	ok=false
+fi
+
+TEST package main_test imports archive not binary
+export GOBIN=$(pwd)/testdata/bin
+mkdir -p $GOBIN
+export GOPATH=$(pwd)/testdata
+touch ./testdata/src/main_test/m.go
+if ! ./testgo test main_test; then
+	echo "go test main_test failed without install"
+	ok=false
+elif ! ./testgo install main_test; then
+	echo "go test main_test failed"
+	ok=false
+elif [ "$(./testgo list -f '{{.Stale}}' main_test)" != false ]; then
+	echo "after go install, main listed as stale"
+	ok=false
+elif ! ./testgo test main_test; then
+	echo "go test main_test failed after install"
+	ok=false
+fi
+rm -rf $GOBIN
+unset GOBIN
+
+# And with $GOBIN set, binaries get installed to $GOBIN.
+TEST install into GOBIN
+if ! GOBIN=$(pwd)/testdata/bin1 GOPATH=$(pwd)/testdata ./testgo install go-cmd-test; then
+	echo "go install go-cmd-test failed"
+	ok=false
+elif ! test -x testdata/bin1/go-cmd-test; then
+	echo "go install go-cmd-test did not write to testdata/bin1/go-cmd-test"
+	ok=false
+fi
+
+# Without $GOBIN set, installing a program outside $GOPATH should fail
+# (there is nowhere to install it).
+TEST install without destination fails
+if ./testgo install testdata/src/go-cmd-test/helloworld.go 2>testdata/err; then
+	echo "go install testdata/src/go-cmd-test/helloworld.go should have failed, did not"
+	ok=false
+elif ! grep 'no install location for .go files listed on command line' testdata/err; then
+	echo "wrong error:"
+	cat testdata/err
+	ok=false
+fi
+rm -f testdata/err
+
+# With $GOBIN set, should install there.
+TEST install to GOBIN '(command-line package)'
+if ! GOBIN=$(pwd)/testdata/bin1 ./testgo install testdata/src/go-cmd-test/helloworld.go; then
+	echo "go install testdata/src/go-cmd-test/helloworld.go failed"
+	ok=false
+elif ! test -x testdata/bin1/helloworld; then
+	echo "go install testdata/src/go-cmd-test/helloworld.go did not write testdata/bin1/helloworld"
+	ok=false
+fi
+
+TEST godoc installs into GOBIN
+d=$(mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir $d/gobin
+GOBIN=$d/gobin ./testgo get code.google.com/p/go.tools/cmd/godoc
+if [ ! -x $d/gobin/godoc ]; then
+	echo did not install godoc to '$GOBIN'
+	GOBIN=$d/gobin ./testgo list -f 'Target: {{.Target}}' code.google.com/p/go.tools/cmd/godoc
+	ok=false
+fi
+
+TEST godoc installs into GOROOT
+GOROOT=$(./testgo env GOROOT)
+rm -f $GOROOT/bin/godoc
+./testgo install code.google.com/p/go.tools/cmd/godoc
+if [ ! -x $GOROOT/bin/godoc ]; then
+	echo did not install godoc to '$GOROOT/bin'
+	./testgo list -f 'Target: {{.Target}}' code.google.com/p/go.tools/cmd/godoc
+	ok=false
+fi
+
+TEST cmd/fix installs into tool
+GOOS=$(./testgo env GOOS)
+GOARCH=$(./testgo env GOARCH)
+rm -f $GOROOT/pkg/tool/${GOOS}_${GOARCH}/fix
+./testgo install cmd/fix
+if [ ! -x $GOROOT/pkg/tool/${GOOS}_${GOARCH}/fix ]; then
+	echo 'did not install cmd/fix to $GOROOT/pkg/tool'
+	GOBIN=$d/gobin ./testgo list -f 'Target: {{.Target}}' cmd/fix
+	ok=false
+fi
+rm -f $GOROOT/pkg/tool/${GOOS}_${GOARCH}/fix
+GOBIN=$d/gobin ./testgo install cmd/fix
+if [ ! -x $GOROOT/pkg/tool/${GOOS}_${GOARCH}/fix ]; then
+	echo 'did not install cmd/fix to $GOROOT/pkg/tool with $GOBIN set'
+	GOBIN=$d/gobin ./testgo list -f 'Target: {{.Target}}' cmd/fix
+	ok=false
+fi
+
+TEST gopath program installs into GOBIN
+mkdir $d/src/progname
+echo 'package main; func main() {}' >$d/src/progname/p.go
+GOBIN=$d/gobin ./testgo install progname
+if [ ! -x $d/gobin/progname ]; then
+	echo 'did not install progname to $GOBIN/progname'
+	./testgo list -f 'Target: {{.Target}}' cmd/api
+	ok=false
+fi
+rm -f $d/gobin/progname $d/bin/progname
+
+TEST gopath program installs into GOPATH/bin
+./testgo install progname
+if [ ! -x $d/bin/progname ]; then
+	echo 'did not install progname to $GOPATH/bin/progname'
+	./testgo list -f 'Target: {{.Target}}' progname
+	ok=false
+fi
+
+unset GOPATH
+rm -rf $d
+
+# Reject relative paths in GOPATH.
+TEST reject relative paths in GOPATH '(command-line package)'
+if GOPATH=. ./testgo build testdata/src/go-cmd-test/helloworld.go; then
+    echo 'GOPATH="." go build should have failed, did not'
+    ok=false
+fi
+
+TEST reject relative paths in GOPATH 
+if GOPATH=:$(pwd)/testdata:. ./testgo build go-cmd-test; then
+    echo 'GOPATH=":$(pwd)/testdata:." go build should have failed, did not'
+    ok=false
+fi
+
+# issue 4104
+TEST go test with package listed multiple times
+if [ $(./testgo test fmt fmt fmt fmt fmt | wc -l) -ne 1 ] ; then
+    echo 'go test fmt fmt fmt fmt fmt tested the same package multiple times'
+    ok=false
+fi
+
+# ensure that output of 'go list' is consistent between runs
+TEST go list is consistent
+./testgo list std > test_std.list
+if ! ./testgo list std | cmp -s test_std.list - ; then
+	echo "go list std ordering is inconsistent"
+	ok=false
+fi
+rm -f test_std.list
+
+# issue 4096. Validate the output of unsuccessful go install foo/quxx 
+TEST unsuccessful go install should mention missing package
+if [ $(./testgo install 'foo/quxx' 2>&1 | grep -c 'cannot find package "foo/quxx" in any of') -ne 1 ] ; then
+	echo 'go install foo/quxx expected error: .*cannot find package "foo/quxx" in any of'
+	ok=false
+fi 
+# test GOROOT search failure is reported
+TEST GOROOT search failure reporting
+if [ $(./testgo install 'foo/quxx' 2>&1 | egrep -c 'foo/quxx \(from \$GOROOT\)$') -ne 1 ] ; then
+        echo 'go install foo/quxx expected error: .*foo/quxx (from $GOROOT)'
+        ok=false
+fi
+# test multiple GOPATH entries are reported separately
+TEST multiple GOPATH entries reported separately
+if [ $(GOPATH=$(pwd)/testdata/a:$(pwd)/testdata/b ./testgo install 'foo/quxx' 2>&1 | egrep -c 'testdata/./src/foo/quxx') -ne 2 ] ; then
+        echo 'go install foo/quxx expected error: .*testdata/a/src/foo/quxx (from $GOPATH)\n.*testdata/b/src/foo/quxx'
+        ok=false
+fi
+# test (from $GOPATH) annotation is reported for the first GOPATH entry
+TEST mention GOPATH in first GOPATH entry
+if [ $(GOPATH=$(pwd)/testdata/a:$(pwd)/testdata/b ./testgo install 'foo/quxx' 2>&1 | egrep -c 'testdata/a/src/foo/quxx \(from \$GOPATH\)$') -ne 1 ] ; then
+        echo 'go install foo/quxx expected error: .*testdata/a/src/foo/quxx (from $GOPATH)'
+        ok=false
+fi
+# but not on the second
+TEST but not the second entry
+if [ $(GOPATH=$(pwd)/testdata/a:$(pwd)/testdata/b ./testgo install 'foo/quxx' 2>&1 | egrep -c 'testdata/b/src/foo/quxx$') -ne 1 ] ; then
+        echo 'go install foo/quxx expected error: .*testdata/b/src/foo/quxx'
+        ok=false
+fi
+# test missing GOPATH is reported
+TEST missing GOPATH is reported
+if [ $(GOPATH= ./testgo install 'foo/quxx' 2>&1 | egrep -c '\(\$GOPATH not set\)$') -ne 1 ] ; then
+        echo 'go install foo/quxx expected error: ($GOPATH not set)'
+        ok=false
+fi
+
+# issue 4186. go get cannot be used to download packages to $GOROOT
+# Test that without GOPATH set, go get should fail
+TEST without GOPATH, go get fails
+d=$(mktemp -d -t testgoXXX)
+mkdir -p $d/src/pkg
+if GOPATH= GOROOT=$d ./testgo get -d code.google.com/p/go.codereview/cmd/hgpatch ; then 
+	echo 'go get code.google.com/p/go.codereview/cmd/hgpatch should not succeed with $GOPATH unset'
+	ok=false
+fi	
+rm -rf $d
+
+# Test that with GOPATH=$GOROOT, go get should fail
+TEST with GOPATH=GOROOT, go get fails
+d=$(mktemp -d -t testgoXXX)
+mkdir -p $d/src/pkg
+if GOPATH=$d GOROOT=$d ./testgo get -d code.google.com/p/go.codereview/cmd/hgpatch ; then
+        echo 'go get code.google.com/p/go.codereview/cmd/hgpatch should not succeed with GOPATH=$GOROOT'
+        ok=false
+fi
+rm -rf $d
+
+TEST ldflags arguments with spaces '(issue 3941)'
+d=$(mktemp -d -t testgoXXX)
+cat >$d/main.go<<EOF
+package main
+var extern string
+func main() {
+	println(extern)
+}
+EOF
+./testgo run -ldflags '-X main.extern "hello world"' $d/main.go 2>hello.out
+if ! grep -q '^hello world' hello.out; then
+	echo "ldflags -X main.extern 'hello world' failed. Output:"
+	cat hello.out
+	ok=false
+fi
+rm -rf $d hello.out
+
+TEST go test -cpuprofile leaves binary behind
+./testgo test -cpuprofile strings.prof strings || ok=false
+if [ ! -x strings.test ]; then
+	echo "go test -cpuprofile did not create strings.test"
+	ok=false
+fi
+rm -f strings.prof strings.test
+
+TEST symlinks do not confuse go list '(issue 4568)'
+old=$(pwd)
+tmp=$(cd /tmp && pwd -P)
+d=$(TMPDIR=$tmp mktemp -d -t testgoXXX)
+mkdir -p $d/src
+(
+	ln -s $d $d/src/dir1
+	cd $d/src
+	echo package p >dir1/p.go
+	export GOPATH=$d
+	if [ "$($old/testgo list -f '{{.Root}}' dir1)" != "$d" ]; then
+		echo Confused by symlinks.
+		echo "Package in current directory $(pwd) should have Root $d"
+		env|grep WD
+		$old/testgo list -json . dir1
+		touch $d/failed
+	fi		
+)
+if [ -f $d/failed ]; then
+	ok=false
+fi
+rm -rf $d
+
+TEST 'install with tags (issue 4515)'
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+mkdir -p $d/src/example/a $d/src/example/b $d/bin
+cat >$d/src/example/a/main.go <<EOF
+package main
+func main() {}
+EOF
+cat >$d/src/example/b/main.go <<EOF
+// +build mytag
+
+package main
+func main() {}
+EOF
+GOPATH=$d ./testgo install -tags mytag example/a example/b || ok=false
+if [ ! -x $d/bin/a -o ! -x $d/bin/b ]; then
+	echo go install example/a example/b did not install binaries
+	ok=false
+fi
+rm -f $d/bin/*
+GOPATH=$d ./testgo install -tags mytag example/... || ok=false
+if [ ! -x $d/bin/a -o ! -x $d/bin/b ]; then
+	echo go install example/... did not install binaries
+	ok=false
+fi
+rm -f $d/bin/*go
+export GOPATH=$d
+if [ "$(./testgo list -tags mytag example/b...)" != "example/b" ]; then
+	echo go list example/b did not find example/b
+	ok=false
+fi
+unset GOPATH
+rm -rf $d
+
+TEST case collisions '(issue 4773)'
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir -p $d/src/example/{a/pkg,a/Pkg,b}
+cat >$d/src/example/a/a.go <<EOF
+package p
+import (
+	_ "example/a/pkg"
+	_ "example/a/Pkg"
+)
+EOF
+cat >$d/src/example/a/pkg/pkg.go <<EOF
+package pkg
+EOF
+cat >$d/src/example/a/Pkg/pkg.go <<EOF
+package pkg
+EOF
+if ./testgo list example/a 2>$d/out; then
+	echo go list example/a should have failed, did not.
+	ok=false
+elif ! grep "case-insensitive import collision" $d/out >/dev/null; then
+	echo go list example/a did not report import collision.
+	ok=false
+fi
+cat >$d/src/example/b/file.go <<EOF
+package b
+EOF
+cat >$d/src/example/b/FILE.go <<EOF
+package b
+EOF
+if [ $(ls $d/src/example/b | wc -l) = 2 ]; then
+	# case-sensitive file system, let directory read find both files
+	args="example/b"
+else
+	# case-insensitive file system, list files explicitly on command line.
+	args="$d/src/example/b/file.go $d/src/example/b/FILE.go"
+fi
+if ./testgo list $args 2>$d/out; then
+	echo go list example/b should have failed, did not.
+	ok=false
+elif ! grep "case-insensitive file name collision" $d/out >/dev/null; then
+	echo go list example/b did not report file name collision.
+	ok=false
+fi
+
+TEST go get cover
+./testgo get code.google.com/p/go.tools/cmd/cover || ok=false
+
+unset GOPATH
+rm -rf $d
+
+TEST shadowing logic
+export GOPATH=$(pwd)/testdata/shadow/root1:$(pwd)/testdata/shadow/root2
+
+# The math in root1 is not "math" because the standard math is.
+cdir=$(./testgo list -f '({{.ImportPath}}) ({{.ConflictDir}})' ./testdata/shadow/root1/src/math)
+if [ "$cdir" != "(_$(pwd)/testdata/shadow/root1/src/math) ($GOROOT/src/pkg/math)" ]; then
+	echo shadowed math is not shadowed: "$cdir"
+	ok=false
+fi
+
+# The foo in root1 is "foo".
+cdir=$(./testgo list -f '({{.ImportPath}}) ({{.ConflictDir}})' ./testdata/shadow/root1/src/foo)
+if [ "$cdir" != "(foo) ()" ]; then
+	echo unshadowed foo is shadowed: "$cdir"
+	ok=false
+fi
+
+# The foo in root2 is not "foo" because the foo in root1 got there first.
+cdir=$(./testgo list -f '({{.ImportPath}}) ({{.ConflictDir}})' ./testdata/shadow/root2/src/foo)
+if [ "$cdir" != "(_$(pwd)/testdata/shadow/root2/src/foo) ($(pwd)/testdata/shadow/root1/src/foo)" ]; then
+	echo shadowed foo is not shadowed: "$cdir"
+	ok=false
+fi
+
+# The error for go install should mention the conflicting directory.
+err=$(! ./testgo install ./testdata/shadow/root2/src/foo 2>&1)
+if [ "$err" != "go install: no install location for $(pwd)/testdata/shadow/root2/src/foo: hidden by $(pwd)/testdata/shadow/root1/src/foo" ]; then
+	echo wrong shadowed install error: "$err"
+	ok=false
+fi
+
+# Only succeeds if source order is preserved.
+TEST source file name order preserved
+./testgo test testdata/example[12]_test.go || ok=false
+
+# Check that coverage analysis works at all.
+# Don't worry about the exact numbers but require not 0.0%.
+checkcoverage() {
+	if grep '[^0-9]0\.0%' testdata/cover.txt >/dev/null; then
+		echo 'some coverage results are 0.0%'
+		ok=false
+	fi
+	cat testdata/cover.txt
+	rm -f testdata/cover.txt
+}
+	
+TEST coverage runs
+./testgo test -short -coverpkg=strings strings regexp >testdata/cover.txt 2>&1 || ok=false
+./testgo test -short -cover strings math regexp >>testdata/cover.txt 2>&1 || ok=false
+checkcoverage
+
+# Check that coverage analysis uses set mode.
+TEST coverage uses set mode
+if ./testgo test -short -cover encoding/binary -coverprofile=testdata/cover.out >testdata/cover.txt 2>&1; then
+	if ! grep -q 'mode: set' testdata/cover.out; then
+		ok=false
+	fi
+	checkcoverage
+else
+	ok=false
+fi
+rm -f testdata/cover.out testdata/cover.txt
+
+TEST coverage uses atomic mode for -race.
+if ./testgo test -short -race -cover encoding/binary -coverprofile=testdata/cover.out >testdata/cover.txt 2>&1; then
+	if ! grep -q 'mode: atomic' testdata/cover.out; then
+		ok=false
+	fi
+	checkcoverage
+else
+	ok=false
+fi
+rm -f testdata/cover.out
+
+TEST coverage uses actual setting to override even for -race.
+if ./testgo test -short -race -cover encoding/binary -covermode=count -coverprofile=testdata/cover.out >testdata/cover.txt 2>&1; then
+	if ! grep -q 'mode: count' testdata/cover.out; then
+		ok=false
+	fi
+	checkcoverage
+else
+	ok=false
+fi
+rm -f testdata/cover.out
+
+TEST coverage with cgo
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+./testgo test -short -cover ./testdata/cgocover >testdata/cover.txt 2>&1 || ok=false
+checkcoverage
+
+TEST cgo depends on syscall
+rm -rf $GOROOT/pkg/*_race
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir -p $d/src/foo
+echo '
+package foo
+//#include <stdio.h>
+import "C"
+' >$d/src/foo/foo.go
+./testgo build -race foo || ok=false
+rm -rf $d
+unset GOPATH
+
+TEST cgo shows full path names
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir -p $d/src/x/y/dirname
+echo '
+package foo
+import "C"
+func f() {
+' >$d/src/x/y/dirname/foo.go
+if ./testgo build x/y/dirname >$d/err 2>&1; then
+	echo build succeeded unexpectedly.
+	ok=false
+elif ! grep x/y/dirname $d/err >/dev/null; then
+	echo error did not use full path.
+	cat $d/err
+	ok=false
+fi
+rm -rf $d
+unset GOPATH
+
+TEST 'cgo handles -Wl,$ORIGIN'
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir -p $d/src/origin
+echo '
+package origin
+// #cgo !darwin LDFLAGS: -Wl,-rpath -Wl,$ORIGIN
+// void f(void) {}
+import "C"
+
+func f() { C.f() }
+' >$d/src/origin/origin.go
+if ! ./testgo build origin; then
+	echo build failed
+	ok=false
+fi
+rm -rf $d
+unset GOPATH
+
+TEST 'Issue 6480: "go test -c -test.bench=XXX fmt" should not hang'
+if ! ./testgo test -c -test.bench=XXX fmt; then
+	echo build test failed
+	ok=false
+fi
+rm -f fmt.test
+
+TEST 'Issue 7573: cmd/cgo: undefined reference when linking a C-library using gccgo'
+d=$(mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir -p $d/src/cgoref
+ldflags="-L alibpath -lalib"
+echo "
+package main
+// #cgo LDFLAGS: $ldflags
+// void f(void) {}
+import \"C\"
+
+func main() { C.f() }
+" >$d/src/cgoref/cgoref.go
+go_cmds="$(./testgo build -n -compiler gccgo cgoref 2>&1 1>/dev/null)"
+ldflags_count="$(echo "$go_cmds" | egrep -c "^gccgo.*$(echo $ldflags | sed -e 's/-/\\-/g')" || true)"
+if [ "$ldflags_count" -lt 1 ]; then
+	echo "No Go-inline "#cgo LDFLAGS:" (\"$ldflags\") passed to gccgo linking stage."
+	ok=false
+fi
+rm -rf $d
+unset ldflags_count
+unset go_cmds
+unset ldflags
+unset GOPATH
+
+TEST list template can use context function
+if ! ./testgo list -f "GOARCH: {{context.GOARCH}}"; then 
+	echo unable to use context in list template
+	ok=false
+fi
+
+TEST 'Issue 7108: cmd/go: "go test" should fail if package does not build'
+export GOPATH=$(pwd)/testdata
+if ./testgo test notest >/dev/null 2>&1; then
+	echo 'go test notest succeeded, but should fail'
+	ok=false
+fi
+unset GOPATH
+
+TEST 'Issue 6844: cmd/go: go test -a foo does not rebuild regexp'
+if ! ./testgo test -x -a -c testdata/dep_test.go 2>deplist; then
+	echo "go test -x -a -c testdata/dep_test.go failed"
+	ok=false
+elif ! grep -q regexp deplist; then
+	echo "go test -x -a -c testdata/dep_test.go did not rebuild regexp"
+	ok=false
+fi
+rm -f deplist
+rm -f deps.test
+
+TEST list template can use context function
+if ! ./testgo list -f "GOARCH: {{context.GOARCH}}"; then 
+	echo unable to use context in list template
+	ok=false
+fi
+
+TEST build -i installs dependencies
+d=$(TMPDIR=/var/tmp mktemp -d -t testgoXXX)
+export GOPATH=$d
+mkdir -p $d/src/x/y/foo $d/src/x/y/bar
+echo '
+package foo
+func F() {}
+' >$d/src/x/y/foo/foo.go
+echo '
+package bar
+import "x/y/foo"
+func F() { foo.F() }
+' >$d/src/x/y/bar/bar.go
+if ! ./testgo build -v -i x/y/bar &> $d/err; then
+	echo build -i failed
+	cat $d/err
+	ok=false
+elif ! grep x/y/foo $d/err >/dev/null; then
+	echo first build -i did not build x/y/foo
+	cat $d/err
+	ok=false
+fi
+if ! ./testgo build -v -i x/y/bar &> $d/err; then
+	echo second build -i failed
+	cat $d/err
+	ok=false
+elif grep x/y/foo $d/err >/dev/null; then
+	echo second build -i built x/y/foo
+	cat $d/err
+	ok=false
+fi
+rm -rf $d
+unset GOPATH
+
+TEST 'go build in test-only directory fails with a good error'
+if ./testgo build ./testdata/testonly 2>testdata/err.out; then
+	echo "go build ./testdata/testonly succeeded, should have failed"
+	ok=false
+elif ! grep 'no buildable Go' testdata/err.out >/dev/null; then
+	echo "go build ./testdata/testonly produced unexpected error:"
+	cat testdata/err.out
+	ok=false
+fi
+rm -f testdata/err.out
+
+TEST 'go test detects test-only import cycles'
+export GOPATH=$(pwd)/testdata
+if ./testgo test -c testcycle/p3 2>testdata/err.out; then
+	echo "go test testcycle/p3 succeeded, should have failed"
+	ok=false
+elif ! grep 'import cycle not allowed in test' testdata/err.out >/dev/null; then
+	echo "go test testcycle/p3 produced unexpected error:"
+	cat testdata/err.out
+	ok=false
+fi
+rm -f testdata/err.out
+unset GOPATH
+
+TEST 'go test foo_test.go works'
+if ! ./testgo test testdata/standalone_test.go; then
+	echo "go test testdata/standalone_test.go failed"
+	ok=false
+fi
+
+TEST 'go test xtestonly works'
+export GOPATH=$(pwd)/testdata
+./testgo clean -i xtestonly
+if ! ./testgo test xtestonly >/dev/null; then
+	echo "go test xtestonly failed"
+	ok=false
+fi
+unset GOPATH
+
+
+# clean up
+if $started; then stop; fi
+rm -rf testdata/bin testdata/bin1
+rm -f testgo
+
+if $allok; then
+	echo PASS
+else
+	echo FAIL
+	exit 1
+fi

libgo/go/cmd/go/testdata/cgocover/p.go

@@ -0,0 +1,19 @@
+package p
+
+/*
+void
+f(void)
+{
+}
+*/
+import "C"
+
+var b bool
+
+func F() {
+	if b {
+		for {
+		}
+	}
+	C.f()
+}

libgo/go/cmd/go/testdata/cgocover/p_test.go

@@ -0,0 +1,7 @@
+package p
+
+import "testing"
+
+func TestF(t *testing.T) {
+	F()
+}

libgo/go/cmd/go/testdata/dep_test.go

@@ -0,0 +1,7 @@
+// Copyright 2014 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.
+
+package deps
+
+import _ "testing"

libgo/go/cmd/go/testdata/example1_test.go

@@ -0,0 +1,23 @@
+// Copyright 2013 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.
+
+// Make sure that go test runs Example_Z before Example_A, preserving source order.
+
+package p
+
+import "fmt"
+
+var n int
+
+func Example_Z() {
+	n++
+	fmt.Println(n)
+	// Output: 1
+}
+
+func Example_A() {
+	n++
+	fmt.Println(n)
+	// Output: 2
+}

libgo/go/cmd/go/testdata/example2_test.go

@@ -0,0 +1,21 @@
+// Copyright 2013 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.
+
+// Make sure that go test runs Example_Y before Example_B, preserving source order.
+
+package p
+
+import "fmt"
+
+func Example_Y() {
+	n++
+	fmt.Println(n)
+	// Output: 3
+}
+
+func Example_B() {
+	n++
+	fmt.Println(n)
+	// Output: 4
+}

libgo/go/cmd/go/testdata/local/easy.go

@@ -0,0 +1,7 @@
+package main
+
+import "./easysub"
+
+func main() {
+	easysub.Hello()
+}

libgo/go/cmd/go/testdata/local/easysub/easysub.go

@@ -0,0 +1,7 @@
+package easysub
+
+import "fmt"
+
+func Hello() {
+	fmt.Println("easysub.Hello")
+}

libgo/go/cmd/go/testdata/local/easysub/main.go

@@ -0,0 +1,9 @@
+// +build ignore
+
+package main
+
+import "."
+
+func main() {
+	easysub.Hello()
+}

libgo/go/cmd/go/testdata/local/hard.go

@@ -0,0 +1,7 @@
+package main
+
+import "./sub"
+
+func main() {
+	sub.Hello()
+}

libgo/go/cmd/go/testdata/local/sub/sub.go

@@ -0,0 +1,12 @@
+package sub
+
+import (
+	"fmt"
+
+	subsub "./sub"
+)
+
+func Hello() {
+	fmt.Println("sub.Hello")
+	subsub.Hello()
+}

libgo/go/cmd/go/testdata/local/sub/sub/subsub.go

@@ -0,0 +1,7 @@
+package subsub
+
+import "fmt"
+
+func Hello() {
+	fmt.Println("subsub.Hello")
+}

libgo/go/cmd/go/testdata/shadow/root1/src/foo/foo.go

@@ -0,0 +1 @@
+package foo

libgo/go/cmd/go/testdata/shadow/root1/src/math/math.go

@@ -0,0 +1 @@
+package math

libgo/go/cmd/go/testdata/shadow/root2/src/foo/foo.go

@@ -0,0 +1 @@
+package foo

libgo/go/cmd/go/testdata/src/badpkg/x.go

@@ -0,0 +1 @@
+pkg badpkg

libgo/go/cmd/go/testdata/src/cgotest/m.go

@@ -0,0 +1,5 @@
+package cgotest
+
+import "C"
+
+var _ C.int

libgo/go/cmd/go/testdata/src/go-cmd-test/helloworld.go

@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	println("hello world")
+}

libgo/go/cmd/go/testdata/src/main_test/m.go

@@ -0,0 +1,4 @@
+package main
+
+func F()    {}
+func main() {}

libgo/go/cmd/go/testdata/src/main_test/m_test.go

@@ -0,0 +1,10 @@
+package main_test
+
+import (
+	. "main_test"
+	"testing"
+)
+
+func Test1(t *testing.T) {
+	F()
+}

libgo/go/cmd/go/testdata/src/notest/hello.go

@@ -0,0 +1,6 @@
+package notest
+
+func hello() {
+	println("hello world")
+}
+Hello world

libgo/go/cmd/go/testdata/src/syntaxerror/x.go

@@ -0,0 +1 @@
+package p

libgo/go/cmd/go/testdata/src/syntaxerror/x_test.go

@@ -0,0 +1,4 @@
+package p
+
+func f() (x.y, z int) {
+}

libgo/go/cmd/go/testdata/src/testcycle/p1/p1.go

@@ -0,0 +1,7 @@
+package p1
+
+import _ "testcycle/p2"
+
+func init() {
+	println("p1 init")
+}

libgo/go/cmd/go/testdata/src/testcycle/p1/p1_test.go

@@ -0,0 +1,6 @@
+package p1
+
+import "testing"
+
+func Test(t *testing.T) {
+}

libgo/go/cmd/go/testdata/src/testcycle/p2/p2.go

@@ -0,0 +1,7 @@
+package p2
+
+import _ "testcycle/p3"
+
+func init() {
+	println("p2 init")
+}

libgo/go/cmd/go/testdata/src/testcycle/p3/p3.go

@@ -0,0 +1,5 @@
+package p3
+
+func init() {
+	println("p3 init")
+}

libgo/go/cmd/go/testdata/src/testcycle/p3/p3_test.go

@@ -0,0 +1,10 @@
+package p3
+
+import (
+	"testing"
+
+	_ "testcycle/p1"
+)
+
+func Test(t *testing.T) {
+}

libgo/go/cmd/go/testdata/src/xtestonly/f.go

@@ -0,0 +1,3 @@
+package xtestonly
+
+func F() int { return 42 }

libgo/go/cmd/go/testdata/src/xtestonly/f_test.go

@@ -0,0 +1,12 @@
+package xtestonly_test
+
+import (
+	"testing"
+	"xtestonly"
+)
+
+func TestF(t *testing.T) {
+	if x := xtestonly.F(); x != 42 {
+		t.Errorf("f.F() = %d, want 42", x)
+	}
+}

libgo/go/cmd/go/testdata/standalone_test.go

@@ -0,0 +1,6 @@
+package standalone_test
+
+import "testing"
+
+func Test(t *testing.T) {
+}

libgo/go/cmd/go/testdata/testimport/p.go

@@ -0,0 +1,3 @@
+package p
+
+func F() int { return 1 }

libgo/go/cmd/go/testdata/testimport/p1/p1.go

@@ -0,0 +1,3 @@
+package p1
+
+func F() int { return 1 }

libgo/go/cmd/go/testdata/testimport/p2/p2.go

@@ -0,0 +1,3 @@
+package p2
+
+func F() int { return 1 }

libgo/go/cmd/go/testdata/testimport/p_test.go

@@ -0,0 +1,13 @@
+package p
+
+import (
+	"./p1"
+
+	"testing"
+)
+
+func TestF(t *testing.T) {
+	if F() != p1.F() {
+		t.Fatal(F())
+	}
+}

libgo/go/cmd/go/testdata/testimport/x_test.go

@@ -0,0 +1,15 @@
+package p_test
+
+import (
+	. "../testimport"
+
+	"./p2"
+
+	"testing"
+)
+
+func TestF1(t *testing.T) {
+	if F() != p2.F() {
+		t.Fatal(F())
+	}
+}

libgo/go/cmd/go/testdata/testonly/p_test.go

@@ -0,0 +1 @@
+package p

libgo/go/cmd/go/testflag.go

@@ -0,0 +1,318 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// The flag handling part of go test is large and distracting.
+// We can't use the flag package because some of the flags from
+// our command line are for us, and some are for 6.out, and
+// some are for both.
+
+var usageMessage = `Usage of go test:
+  -c=false: compile but do not run the test binary
+  -file=file_test.go: specify file to use for tests;
+      use multiple times for multiple files
+  -p=n: build and test up to n packages in parallel
+  -x=false: print command lines as they are executed
+
+  // These flags can be passed with or without a "test." prefix: -v or -test.v.
+  -bench="": passes -test.bench to test
+  -benchmem=false: print memory allocation statistics for benchmarks
+  -benchtime=1s: passes -test.benchtime to test
+  -cover=false: enable coverage analysis
+  -covermode="set": specifies mode for coverage analysis
+  -coverpkg="": comma-separated list of packages for coverage analysis
+  -coverprofile="": passes -test.coverprofile to test if -cover
+  -cpu="": passes -test.cpu to test
+  -cpuprofile="": passes -test.cpuprofile to test
+  -memprofile="": passes -test.memprofile to test
+  -memprofilerate=0: passes -test.memprofilerate to test
+  -blockprofile="": pases -test.blockprofile to test
+  -blockprofilerate=0: passes -test.blockprofilerate to test
+  -outputdir=$PWD: passes -test.outputdir to test
+  -parallel=0: passes -test.parallel to test
+  -run="": passes -test.run to test
+  -short=false: passes -test.short to test
+  -timeout=0: passes -test.timeout to test
+  -v=false: passes -test.v to test
+`
+
+// usage prints a usage message and exits.
+func testUsage() {
+	fmt.Fprint(os.Stderr, usageMessage)
+	setExitStatus(2)
+	exit()
+}
+
+// testFlagSpec defines a flag we know about.
+type testFlagSpec struct {
+	name       string
+	boolVar    *bool
+	passToTest bool // pass to Test
+	multiOK    bool // OK to have multiple instances
+	present    bool // flag has been seen
+}
+
+// testFlagDefn is the set of flags we process.
+var testFlagDefn = []*testFlagSpec{
+	// local.
+	{name: "c", boolVar: &testC},
+	{name: "file", multiOK: true},
+	{name: "cover", boolVar: &testCover},
+	{name: "coverpkg"},
+
+	// build flags.
+	{name: "a", boolVar: &buildA},
+	{name: "n", boolVar: &buildN},
+	{name: "p"},
+	{name: "x", boolVar: &buildX},
+	{name: "i", boolVar: &buildI},
+	{name: "work", boolVar: &buildWork},
+	{name: "ccflags"},
+	{name: "gcflags"},
+	{name: "exec"},
+	{name: "ldflags"},
+	{name: "gccgoflags"},
+	{name: "tags"},
+	{name: "compiler"},
+	{name: "race", boolVar: &buildRace},
+	{name: "installsuffix"},
+
+	// passed to 6.out, adding a "test." prefix to the name if necessary: -v becomes -test.v.
+	{name: "bench", passToTest: true},
+	{name: "benchmem", boolVar: new(bool), passToTest: true},
+	{name: "benchtime", passToTest: true},
+	{name: "covermode"},
+	{name: "coverprofile", passToTest: true},
+	{name: "cpu", passToTest: true},
+	{name: "cpuprofile", passToTest: true},
+	{name: "memprofile", passToTest: true},
+	{name: "memprofilerate", passToTest: true},
+	{name: "blockprofile", passToTest: true},
+	{name: "blockprofilerate", passToTest: true},
+	{name: "outputdir", passToTest: true},
+	{name: "parallel", passToTest: true},
+	{name: "run", passToTest: true},
+	{name: "short", boolVar: new(bool), passToTest: true},
+	{name: "timeout", passToTest: true},
+	{name: "v", boolVar: &testV, passToTest: true},
+}
+
+// testFlags processes the command line, grabbing -x and -c, rewriting known flags
+// to have "test" before them, and reading the command line for the 6.out.
+// Unfortunately for us, we need to do our own flag processing because go test
+// grabs some flags but otherwise its command line is just a holding place for
+// pkg.test's arguments.
+// We allow known flags both before and after the package name list,
+// to allow both
+//	go test fmt -custom-flag-for-fmt-test
+//	go test -x math
+func testFlags(args []string) (packageNames, passToTest []string) {
+	inPkg := false
+	outputDir := ""
+	for i := 0; i < len(args); i++ {
+		if !strings.HasPrefix(args[i], "-") {
+			if !inPkg && packageNames == nil {
+				// First package name we've seen.
+				inPkg = true
+			}
+			if inPkg {
+				packageNames = append(packageNames, args[i])
+				continue
+			}
+		}
+
+		if inPkg {
+			// Found an argument beginning with "-"; end of package list.
+			inPkg = false
+		}
+
+		f, value, extraWord := testFlag(args, i)
+		if f == nil {
+			// This is a flag we do not know; we must assume
+			// that any args we see after this might be flag
+			// arguments, not package names.
+			inPkg = false
+			if packageNames == nil {
+				// make non-nil: we have seen the empty package list
+				packageNames = []string{}
+			}
+			passToTest = append(passToTest, args[i])
+			continue
+		}
+		var err error
+		switch f.name {
+		// bool flags.
+		case "a", "c", "i", "n", "x", "v", "race", "cover", "work":
+			setBoolFlag(f.boolVar, value)
+		case "p":
+			setIntFlag(&buildP, value)
+		case "exec":
+			execCmd, err = splitQuotedFields(value)
+			if err != nil {
+				fatalf("invalid flag argument for -%s: %v", f.name, err)
+			}
+		case "ccflags":
+			buildCcflags, err = splitQuotedFields(value)
+			if err != nil {
+				fatalf("invalid flag argument for -%s: %v", f.name, err)
+			}
+		case "gcflags":
+			buildGcflags, err = splitQuotedFields(value)
+			if err != nil {
+				fatalf("invalid flag argument for -%s: %v", f.name, err)
+			}
+		case "ldflags":
+			buildLdflags, err = splitQuotedFields(value)
+			if err != nil {
+				fatalf("invalid flag argument for -%s: %v", f.name, err)
+			}
+		case "gccgoflags":
+			buildGccgoflags, err = splitQuotedFields(value)
+			if err != nil {
+				fatalf("invalid flag argument for -%s: %v", f.name, err)
+			}
+		case "tags":
+			buildContext.BuildTags = strings.Fields(value)
+		case "compiler":
+			buildCompiler{}.Set(value)
+		case "file":
+			testFiles = append(testFiles, value)
+		case "bench":
+			// record that we saw the flag; don't care about the value
+			testBench = true
+		case "timeout":
+			testTimeout = value
+		case "blockprofile", "cpuprofile", "memprofile":
+			testProfile = true
+			testNeedBinary = true
+		case "coverpkg":
+			testCover = true
+			if value == "" {
+				testCoverPaths = nil
+			} else {
+				testCoverPaths = strings.Split(value, ",")
+			}
+		case "coverprofile":
+			testCover = true
+			testProfile = true
+		case "covermode":
+			switch value {
+			case "set", "count", "atomic":
+				testCoverMode = value
+			default:
+				fatalf("invalid flag argument for -cover: %q", value)
+			}
+			testCover = true
+		case "outputdir":
+			outputDir = value
+		}
+		if extraWord {
+			i++
+		}
+		if f.passToTest {
+			passToTest = append(passToTest, "-test."+f.name+"="+value)
+		}
+	}
+
+	if testCoverMode == "" {
+		testCoverMode = "set"
+		if buildRace {
+			// Default coverage mode is atomic when -race is set.
+			testCoverMode = "atomic"
+		}
+	}
+
+	// Tell the test what directory we're running in, so it can write the profiles there.
+	if testProfile && outputDir == "" {
+		dir, err := os.Getwd()
+		if err != nil {
+			fatalf("error from os.Getwd: %s", err)
+		}
+		passToTest = append(passToTest, "-test.outputdir", dir)
+	}
+	return
+}
+
+// testFlag sees if argument i is a known flag and returns its definition, value, and whether it consumed an extra word.
+func testFlag(args []string, i int) (f *testFlagSpec, value string, extra bool) {
+	arg := args[i]
+	if strings.HasPrefix(arg, "--") { // reduce two minuses to one
+		arg = arg[1:]
+	}
+	switch arg {
+	case "-?", "-h", "-help":
+		usage()
+	}
+	if arg == "" || arg[0] != '-' {
+		return
+	}
+	name := arg[1:]
+	// If there's already "test.", drop it for now.
+	name = strings.TrimPrefix(name, "test.")
+	equals := strings.Index(name, "=")
+	if equals >= 0 {
+		value = name[equals+1:]
+		name = name[:equals]
+	}
+	for _, f = range testFlagDefn {
+		if name == f.name {
+			// Booleans are special because they have modes -x, -x=true, -x=false.
+			if f.boolVar != nil {
+				if equals < 0 { // otherwise, it's been set and will be verified in setBoolFlag
+					value = "true"
+				} else {
+					// verify it parses
+					setBoolFlag(new(bool), value)
+				}
+			} else { // Non-booleans must have a value.
+				extra = equals < 0
+				if extra {
+					if i+1 >= len(args) {
+						testSyntaxError("missing argument for flag " + f.name)
+					}
+					value = args[i+1]
+				}
+			}
+			if f.present && !f.multiOK {
+				testSyntaxError(f.name + " flag may be set only once")
+			}
+			f.present = true
+			return
+		}
+	}
+	f = nil
+	return
+}
+
+// setBoolFlag sets the addressed boolean to the value.
+func setBoolFlag(flag *bool, value string) {
+	x, err := strconv.ParseBool(value)
+	if err != nil {
+		testSyntaxError("illegal bool flag value " + value)
+	}
+	*flag = x
+}
+
+// setIntFlag sets the addressed integer to the value.
+func setIntFlag(flag *int, value string) {
+	x, err := strconv.Atoi(value)
+	if err != nil {
+		testSyntaxError("illegal int flag value " + value)
+	}
+	*flag = x
+}
+
+func testSyntaxError(msg string) {
+	fmt.Fprintf(os.Stderr, "go test: %s\n", msg)
+	fmt.Fprintf(os.Stderr, `run "go help test" or "go help testflag" for more information`+"\n")
+	os.Exit(2)
+}

libgo/go/cmd/go/tool.go

@@ -0,0 +1,156 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"fmt"
+	"go/build"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+)
+
+var cmdTool = &Command{
+	Run:       runTool,
+	UsageLine: "tool [-n] command [args...]",
+	Short:     "run specified go tool",
+	Long: `
+Tool runs the go tool command identified by the arguments.
+With no arguments it prints the list of known tools.
+
+The -n flag causes tool to print the command that would be
+executed but not execute it.
+
+For more about each tool command, see 'go tool command -h'.
+`,
+}
+
+var (
+	toolGOOS      = runtime.GOOS
+	toolGOARCH    = runtime.GOARCH
+	toolIsWindows = toolGOOS == "windows"
+	toolDir       = build.ToolDir
+
+	toolN bool
+)
+
+func init() {
+	cmdTool.Flag.BoolVar(&toolN, "n", false, "")
+}
+
+const toolWindowsExtension = ".exe"
+
+func tool(toolName string) string {
+	toolPath := filepath.Join(toolDir, toolName)
+	if toolIsWindows && toolName != "pprof" {
+		toolPath += toolWindowsExtension
+	}
+	// Give a nice message if there is no tool with that name.
+	if _, err := os.Stat(toolPath); err != nil {
+		if isInGoToolsRepo(toolName) {
+			fmt.Fprintf(os.Stderr, "go tool: no such tool %q; to install:\n\tgo get code.google.com/p/go.tools/cmd/%s\n", toolName, toolName)
+		} else {
+			fmt.Fprintf(os.Stderr, "go tool: no such tool %q\n", toolName)
+		}
+		setExitStatus(3)
+		exit()
+	}
+	return toolPath
+}
+
+func isInGoToolsRepo(toolName string) bool {
+	switch toolName {
+	case "cover", "vet":
+		return true
+	}
+	return false
+}
+
+func runTool(cmd *Command, args []string) {
+	if len(args) == 0 {
+		listTools()
+		return
+	}
+	toolName := args[0]
+	// The tool name must be lower-case letters, numbers or underscores.
+	for _, c := range toolName {
+		switch {
+		case 'a' <= c && c <= 'z', '0' <= c && c <= '9', c == '_':
+		default:
+			fmt.Fprintf(os.Stderr, "go tool: bad tool name %q\n", toolName)
+			setExitStatus(2)
+			return
+		}
+	}
+	toolPath := tool(toolName)
+	if toolPath == "" {
+		return
+	}
+	if toolIsWindows && toolName == "pprof" {
+		args = append([]string{"perl", toolPath}, args[1:]...)
+		var err error
+		toolPath, err = exec.LookPath("perl")
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "go tool: perl not found\n")
+			setExitStatus(3)
+			return
+		}
+	}
+	if toolN {
+		fmt.Printf("%s %s\n", toolPath, strings.Join(args[1:], " "))
+		return
+	}
+	toolCmd := &exec.Cmd{
+		Path:   toolPath,
+		Args:   args,
+		Stdin:  os.Stdin,
+		Stdout: os.Stdout,
+		Stderr: os.Stderr,
+	}
+	err := toolCmd.Run()
+	if err != nil {
+		// Only print about the exit status if the command
+		// didn't even run (not an ExitError) or it didn't exit cleanly
+		// or we're printing command lines too (-x mode).
+		// Assume if command exited cleanly (even with non-zero status)
+		// it printed any messages it wanted to print.
+		if e, ok := err.(*exec.ExitError); !ok || !e.Exited() || buildX {
+			fmt.Fprintf(os.Stderr, "go tool %s: %s\n", toolName, err)
+		}
+		setExitStatus(1)
+		return
+	}
+}
+
+// listTools prints a list of the available tools in the tools directory.
+func listTools() {
+	f, err := os.Open(toolDir)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: no tool directory: %s\n", err)
+		setExitStatus(2)
+		return
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(-1)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: can't read directory: %s\n", err)
+		setExitStatus(2)
+		return
+	}
+
+	sort.Strings(names)
+	for _, name := range names {
+		// Unify presentation by going to lower case.
+		name = strings.ToLower(name)
+		// If it's windows, don't show the .exe suffix.
+		if toolIsWindows && strings.HasSuffix(name, toolWindowsExtension) {
+			name = name[:len(name)-len(toolWindowsExtension)]
+		}
+		fmt.Println(name)
+	}
+}

libgo/go/cmd/go/vcs.go

@@ -0,0 +1,728 @@
+// Copyright 2012 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.
+
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+// A vcsCmd describes how to use a version control system
+// like Mercurial, Git, or Subversion.
+type vcsCmd struct {
+	name string
+	cmd  string // name of binary to invoke command
+
+	createCmd   string // command to download a fresh copy of a repository
+	downloadCmd string // command to download updates into an existing repository
+
+	tagCmd         []tagCmd // commands to list tags
+	tagLookupCmd   []tagCmd // commands to lookup tags before running tagSyncCmd
+	tagSyncCmd     string   // command to sync to specific tag
+	tagSyncDefault string   // command to sync to default tag
+
+	scheme  []string
+	pingCmd string
+}
+
+// A tagCmd describes a command to list available tags
+// that can be passed to tagSyncCmd.
+type tagCmd struct {
+	cmd     string // command to list tags
+	pattern string // regexp to extract tags from list
+}
+
+// vcsList lists the known version control systems
+var vcsList = []*vcsCmd{
+	vcsHg,
+	vcsGit,
+	vcsSvn,
+	vcsBzr,
+}
+
+// vcsByCmd returns the version control system for the given
+// command name (hg, git, svn, bzr).
+func vcsByCmd(cmd string) *vcsCmd {
+	for _, vcs := range vcsList {
+		if vcs.cmd == cmd {
+			return vcs
+		}
+	}
+	return nil
+}
+
+// vcsHg describes how to use Mercurial.
+var vcsHg = &vcsCmd{
+	name: "Mercurial",
+	cmd:  "hg",
+
+	createCmd:   "clone -U {repo} {dir}",
+	downloadCmd: "pull",
+
+	// We allow both tag and branch names as 'tags'
+	// for selecting a version.  This lets people have
+	// a go.release.r60 branch and a go1 branch
+	// and make changes in both, without constantly
+	// editing .hgtags.
+	tagCmd: []tagCmd{
+		{"tags", `^(\S+)`},
+		{"branches", `^(\S+)`},
+	},
+	tagSyncCmd:     "update -r {tag}",
+	tagSyncDefault: "update default",
+
+	scheme:  []string{"https", "http", "ssh"},
+	pingCmd: "identify {scheme}://{repo}",
+}
+
+// vcsGit describes how to use Git.
+var vcsGit = &vcsCmd{
+	name: "Git",
+	cmd:  "git",
+
+	createCmd:   "clone {repo} {dir}",
+	downloadCmd: "pull --ff-only",
+
+	tagCmd: []tagCmd{
+		// tags/xxx matches a git tag named xxx
+		// origin/xxx matches a git branch named xxx on the default remote repository
+		{"show-ref", `(?:tags|origin)/(\S+)$`},
+	},
+	tagLookupCmd: []tagCmd{
+		{"show-ref tags/{tag} origin/{tag}", `((?:tags|origin)/\S+)$`},
+	},
+	tagSyncCmd:     "checkout {tag}",
+	tagSyncDefault: "checkout master",
+
+	scheme:  []string{"git", "https", "http", "git+ssh"},
+	pingCmd: "ls-remote {scheme}://{repo}",
+}
+
+// vcsBzr describes how to use Bazaar.
+var vcsBzr = &vcsCmd{
+	name: "Bazaar",
+	cmd:  "bzr",
+
+	createCmd: "branch {repo} {dir}",
+
+	// Without --overwrite bzr will not pull tags that changed.
+	// Replace by --overwrite-tags after http://pad.lv/681792 goes in.
+	downloadCmd: "pull --overwrite",
+
+	tagCmd:         []tagCmd{{"tags", `^(\S+)`}},
+	tagSyncCmd:     "update -r {tag}",
+	tagSyncDefault: "update -r revno:-1",
+
+	scheme:  []string{"https", "http", "bzr", "bzr+ssh"},
+	pingCmd: "info {scheme}://{repo}",
+}
+
+// vcsSvn describes how to use Subversion.
+var vcsSvn = &vcsCmd{
+	name: "Subversion",
+	cmd:  "svn",
+
+	createCmd:   "checkout {repo} {dir}",
+	downloadCmd: "update",
+
+	// There is no tag command in subversion.
+	// The branch information is all in the path names.
+
+	scheme:  []string{"https", "http", "svn", "svn+ssh"},
+	pingCmd: "info {scheme}://{repo}",
+}
+
+func (v *vcsCmd) String() string {
+	return v.name
+}
+
+// run runs the command line cmd in the given directory.
+// keyval is a list of key, value pairs.  run expands
+// instances of {key} in cmd into value, but only after
+// splitting cmd into individual arguments.
+// If an error occurs, run prints the command line and the
+// command's combined stdout+stderr to standard error.
+// Otherwise run discards the command's output.
+func (v *vcsCmd) run(dir string, cmd string, keyval ...string) error {
+	_, err := v.run1(dir, cmd, keyval, true)
+	return err
+}
+
+// runVerboseOnly is like run but only generates error output to standard error in verbose mode.
+func (v *vcsCmd) runVerboseOnly(dir string, cmd string, keyval ...string) error {
+	_, err := v.run1(dir, cmd, keyval, false)
+	return err
+}
+
+// runOutput is like run but returns the output of the command.
+func (v *vcsCmd) runOutput(dir string, cmd string, keyval ...string) ([]byte, error) {
+	return v.run1(dir, cmd, keyval, true)
+}
+
+// run1 is the generalized implementation of run and runOutput.
+func (v *vcsCmd) run1(dir string, cmdline string, keyval []string, verbose bool) ([]byte, error) {
+	m := make(map[string]string)
+	for i := 0; i < len(keyval); i += 2 {
+		m[keyval[i]] = keyval[i+1]
+	}
+	args := strings.Fields(cmdline)
+	for i, arg := range args {
+		args[i] = expand(m, arg)
+	}
+
+	_, err := exec.LookPath(v.cmd)
+	if err != nil {
+		fmt.Fprintf(os.Stderr,
+			"go: missing %s command. See http://golang.org/s/gogetcmd\n",
+			v.name)
+		return nil, err
+	}
+
+	cmd := exec.Command(v.cmd, args...)
+	cmd.Dir = dir
+	cmd.Env = envForDir(cmd.Dir)
+	if buildX {
+		fmt.Printf("cd %s\n", dir)
+		fmt.Printf("%s %s\n", v.cmd, strings.Join(args, " "))
+	}
+	var buf bytes.Buffer
+	cmd.Stdout = &buf
+	cmd.Stderr = &buf
+	err = cmd.Run()
+	out := buf.Bytes()
+	if err != nil {
+		if verbose || buildV {
+			fmt.Fprintf(os.Stderr, "# cd %s; %s %s\n", dir, v.cmd, strings.Join(args, " "))
+			os.Stderr.Write(out)
+		}
+		return nil, err
+	}
+	return out, nil
+}
+
+// ping pings to determine scheme to use.
+func (v *vcsCmd) ping(scheme, repo string) error {
+	return v.runVerboseOnly(".", v.pingCmd, "scheme", scheme, "repo", repo)
+}
+
+// create creates a new copy of repo in dir.
+// The parent of dir must exist; dir must not.
+func (v *vcsCmd) create(dir, repo string) error {
+	return v.run(".", v.createCmd, "dir", dir, "repo", repo)
+}
+
+// download downloads any new changes for the repo in dir.
+func (v *vcsCmd) download(dir string) error {
+	if err := v.fixDetachedHead(dir); err != nil {
+		return err
+	}
+	return v.run(dir, v.downloadCmd)
+}
+
+// fixDetachedHead switches a Git repository in dir from a detached head to the master branch.
+// Go versions before 1.2 downloaded Git repositories in an unfortunate way
+// that resulted in the working tree state being on a detached head.
+// That meant the repository was not usable for normal Git operations.
+// Go 1.2 fixed that, but we can't pull into a detached head, so if this is
+// a Git repository we check for being on a detached head and switch to the
+// real branch, almost always called "master".
+// TODO(dsymonds): Consider removing this for Go 1.3.
+func (v *vcsCmd) fixDetachedHead(dir string) error {
+	if v != vcsGit {
+		return nil
+	}
+
+	// "git symbolic-ref HEAD" succeeds iff we are not on a detached head.
+	if err := v.runVerboseOnly(dir, "symbolic-ref HEAD"); err == nil {
+		// not on a detached head
+		return nil
+	}
+	if buildV {
+		log.Printf("%s on detached head; repairing", dir)
+	}
+	return v.run(dir, "checkout master")
+}
+
+// tags returns the list of available tags for the repo in dir.
+func (v *vcsCmd) tags(dir string) ([]string, error) {
+	var tags []string
+	for _, tc := range v.tagCmd {
+		out, err := v.runOutput(dir, tc.cmd)
+		if err != nil {
+			return nil, err
+		}
+		re := regexp.MustCompile(`(?m-s)` + tc.pattern)
+		for _, m := range re.FindAllStringSubmatch(string(out), -1) {
+			tags = append(tags, m[1])
+		}
+	}
+	return tags, nil
+}
+
+// tagSync syncs the repo in dir to the named tag,
+// which either is a tag returned by tags or is v.tagDefault.
+func (v *vcsCmd) tagSync(dir, tag string) error {
+	if v.tagSyncCmd == "" {
+		return nil
+	}
+	if tag != "" {
+		for _, tc := range v.tagLookupCmd {
+			out, err := v.runOutput(dir, tc.cmd, "tag", tag)
+			if err != nil {
+				return err
+			}
+			re := regexp.MustCompile(`(?m-s)` + tc.pattern)
+			m := re.FindStringSubmatch(string(out))
+			if len(m) > 1 {
+				tag = m[1]
+				break
+			}
+		}
+	}
+	if tag == "" && v.tagSyncDefault != "" {
+		return v.run(dir, v.tagSyncDefault)
+	}
+	return v.run(dir, v.tagSyncCmd, "tag", tag)
+}
+
+// A vcsPath describes how to convert an import path into a
+// version control system and repository name.
+type vcsPath struct {
+	prefix string                              // prefix this description applies to
+	re     string                              // pattern for import path
+	repo   string                              // repository to use (expand with match of re)
+	vcs    string                              // version control system to use (expand with match of re)
+	check  func(match map[string]string) error // additional checks
+	ping   bool                                // ping for scheme to use to download repo
+
+	regexp *regexp.Regexp // cached compiled form of re
+}
+
+// vcsForDir inspects dir and its parents to determine the
+// version control system and code repository to use.
+// On return, root is the import path
+// corresponding to the root of the repository
+// (thus root is a prefix of importPath).
+func vcsForDir(p *Package) (vcs *vcsCmd, root string, err error) {
+	// Clean and double-check that dir is in (a subdirectory of) srcRoot.
+	dir := filepath.Clean(p.Dir)
+	srcRoot := filepath.Clean(p.build.SrcRoot)
+	if len(dir) <= len(srcRoot) || dir[len(srcRoot)] != filepath.Separator {
+		return nil, "", fmt.Errorf("directory %q is outside source root %q", dir, srcRoot)
+	}
+
+	origDir := dir
+	for len(dir) > len(srcRoot) {
+		for _, vcs := range vcsList {
+			if fi, err := os.Stat(filepath.Join(dir, "."+vcs.cmd)); err == nil && fi.IsDir() {
+				return vcs, dir[len(srcRoot)+1:], nil
+			}
+		}
+
+		// Move to parent.
+		ndir := filepath.Dir(dir)
+		if len(ndir) >= len(dir) {
+			// Shouldn't happen, but just in case, stop.
+			break
+		}
+		dir = ndir
+	}
+
+	return nil, "", fmt.Errorf("directory %q is not using a known version control system", origDir)
+}
+
+// repoRoot represents a version control system, a repo, and a root of
+// where to put it on disk.
+type repoRoot struct {
+	vcs *vcsCmd
+
+	// repo is the repository URL, including scheme
+	repo string
+
+	// root is the import path corresponding to the root of the
+	// repository
+	root string
+}
+
+var httpPrefixRE = regexp.MustCompile(`^https?:`)
+
+// repoRootForImportPath analyzes importPath to determine the
+// version control system, and code repository to use.
+func repoRootForImportPath(importPath string) (*repoRoot, error) {
+	rr, err := repoRootForImportPathStatic(importPath, "")
+	if err == errUnknownSite {
+		rr, err = repoRootForImportDynamic(importPath)
+
+		// repoRootForImportDynamic returns error detail
+		// that is irrelevant if the user didn't intend to use a
+		// dynamic import in the first place.
+		// Squelch it.
+		if err != nil {
+			if buildV {
+				log.Printf("import %q: %v", importPath, err)
+			}
+			err = fmt.Errorf("unrecognized import path %q", importPath)
+		}
+	}
+
+	if err == nil && strings.Contains(importPath, "...") && strings.Contains(rr.root, "...") {
+		// Do not allow wildcards in the repo root.
+		rr = nil
+		err = fmt.Errorf("cannot expand ... in %q", importPath)
+	}
+	return rr, err
+}
+
+var errUnknownSite = errors.New("dynamic lookup required to find mapping")
+
+// repoRootForImportPathStatic attempts to map importPath to a
+// repoRoot using the commonly-used VCS hosting sites in vcsPaths
+// (github.com/user/dir), or from a fully-qualified importPath already
+// containing its VCS type (foo.com/repo.git/dir)
+//
+// If scheme is non-empty, that scheme is forced.
+func repoRootForImportPathStatic(importPath, scheme string) (*repoRoot, error) {
+	// A common error is to use https://packagepath because that's what
+	// hg and git require. Diagnose this helpfully.
+	if loc := httpPrefixRE.FindStringIndex(importPath); loc != nil {
+		// The importPath has been cleaned, so has only one slash. The pattern
+		// ignores the slashes; the error message puts them back on the RHS at least.
+		return nil, fmt.Errorf("%q not allowed in import path", importPath[loc[0]:loc[1]]+"//")
+	}
+	for _, srv := range vcsPaths {
+		if !strings.HasPrefix(importPath, srv.prefix) {
+			continue
+		}
+		m := srv.regexp.FindStringSubmatch(importPath)
+		if m == nil {
+			if srv.prefix != "" {
+				return nil, fmt.Errorf("invalid %s import path %q", srv.prefix, importPath)
+			}
+			continue
+		}
+
+		// Build map of named subexpression matches for expand.
+		match := map[string]string{
+			"prefix": srv.prefix,
+			"import": importPath,
+		}
+		for i, name := range srv.regexp.SubexpNames() {
+			if name != "" && match[name] == "" {
+				match[name] = m[i]
+			}
+		}
+		if srv.vcs != "" {
+			match["vcs"] = expand(match, srv.vcs)
+		}
+		if srv.repo != "" {
+			match["repo"] = expand(match, srv.repo)
+		}
+		if srv.check != nil {
+			if err := srv.check(match); err != nil {
+				return nil, err
+			}
+		}
+		vcs := vcsByCmd(match["vcs"])
+		if vcs == nil {
+			return nil, fmt.Errorf("unknown version control system %q", match["vcs"])
+		}
+		if srv.ping {
+			if scheme != "" {
+				match["repo"] = scheme + "://" + match["repo"]
+			} else {
+				for _, scheme := range vcs.scheme {
+					if vcs.ping(scheme, match["repo"]) == nil {
+						match["repo"] = scheme + "://" + match["repo"]
+						break
+					}
+				}
+			}
+		}
+		rr := &repoRoot{
+			vcs:  vcs,
+			repo: match["repo"],
+			root: match["root"],
+		}
+		return rr, nil
+	}
+	return nil, errUnknownSite
+}
+
+// repoRootForImportDynamic finds a *repoRoot for a custom domain that's not
+// statically known by repoRootForImportPathStatic.
+//
+// This handles "vanity import paths" like "name.tld/pkg/foo".
+func repoRootForImportDynamic(importPath string) (*repoRoot, error) {
+	slash := strings.Index(importPath, "/")
+	if slash < 0 {
+		return nil, errors.New("import path doesn't contain a slash")
+	}
+	host := importPath[:slash]
+	if !strings.Contains(host, ".") {
+		return nil, errors.New("import path doesn't contain a hostname")
+	}
+	urlStr, body, err := httpsOrHTTP(importPath)
+	if err != nil {
+		return nil, fmt.Errorf("http/https fetch: %v", err)
+	}
+	defer body.Close()
+	imports, err := parseMetaGoImports(body)
+	if err != nil {
+		return nil, fmt.Errorf("parsing %s: %v", importPath, err)
+	}
+	metaImport, err := matchGoImport(imports, importPath)
+	if err != nil {
+		if err != errNoMatch {
+			return nil, fmt.Errorf("parse %s: %v", urlStr, err)
+		}
+		return nil, fmt.Errorf("parse %s: no go-import meta tags", urlStr)
+	}
+	if buildV {
+		log.Printf("get %q: found meta tag %#v at %s", importPath, metaImport, urlStr)
+	}
+	// If the import was "uni.edu/bob/project", which said the
+	// prefix was "uni.edu" and the RepoRoot was "evilroot.com",
+	// make sure we don't trust Bob and check out evilroot.com to
+	// "uni.edu" yet (possibly overwriting/preempting another
+	// non-evil student).  Instead, first verify the root and see
+	// if it matches Bob's claim.
+	if metaImport.Prefix != importPath {
+		if buildV {
+			log.Printf("get %q: verifying non-authoritative meta tag", importPath)
+		}
+		urlStr0 := urlStr
+		urlStr, body, err = httpsOrHTTP(metaImport.Prefix)
+		if err != nil {
+			return nil, fmt.Errorf("fetch %s: %v", urlStr, err)
+		}
+		imports, err := parseMetaGoImports(body)
+		if err != nil {
+			return nil, fmt.Errorf("parsing %s: %v", importPath, err)
+		}
+		if len(imports) == 0 {
+			return nil, fmt.Errorf("fetch %s: no go-import meta tag", urlStr)
+		}
+		metaImport2, err := matchGoImport(imports, importPath)
+		if err != nil || metaImport != metaImport2 {
+			return nil, fmt.Errorf("%s and %s disagree about go-import for %s", urlStr0, urlStr, metaImport.Prefix)
+		}
+	}
+
+	if !strings.Contains(metaImport.RepoRoot, "://") {
+		return nil, fmt.Errorf("%s: invalid repo root %q; no scheme", urlStr, metaImport.RepoRoot)
+	}
+	rr := &repoRoot{
+		vcs:  vcsByCmd(metaImport.VCS),
+		repo: metaImport.RepoRoot,
+		root: metaImport.Prefix,
+	}
+	if rr.vcs == nil {
+		return nil, fmt.Errorf("%s: unknown vcs %q", urlStr, metaImport.VCS)
+	}
+	return rr, nil
+}
+
+// metaImport represents the parsed <meta name="go-import"
+// content="prefix vcs reporoot" /> tags from HTML files.
+type metaImport struct {
+	Prefix, VCS, RepoRoot string
+}
+
+// errNoMatch is returned from matchGoImport when there's no applicable match.
+var errNoMatch = errors.New("no import match")
+
+// matchGoImport returns the metaImport from imports matching importPath.
+// An error is returned if there are multiple matches.
+// errNoMatch is returned if none match.
+func matchGoImport(imports []metaImport, importPath string) (_ metaImport, err error) {
+	match := -1
+	for i, im := range imports {
+		if !strings.HasPrefix(importPath, im.Prefix) {
+			continue
+		}
+		if match != -1 {
+			err = fmt.Errorf("multiple meta tags match import path %q", importPath)
+			return
+		}
+		match = i
+	}
+	if match == -1 {
+		err = errNoMatch
+		return
+	}
+	return imports[match], nil
+}
+
+// expand rewrites s to replace {k} with match[k] for each key k in match.
+func expand(match map[string]string, s string) string {
+	for k, v := range match {
+		s = strings.Replace(s, "{"+k+"}", v, -1)
+	}
+	return s
+}
+
+// vcsPaths lists the known vcs paths.
+var vcsPaths = []*vcsPath{
+	// Google Code - new syntax
+	{
+		prefix: "code.google.com/",
+		re:     `^(?P<root>code\.google\.com/p/(?P<project>[a-z0-9\-]+)(\.(?P<subrepo>[a-z0-9\-]+))?)(/[A-Za-z0-9_.\-]+)*$`,
+		repo:   "https://{root}",
+		check:  googleCodeVCS,
+	},
+
+	// Google Code - old syntax
+	{
+		re:    `^(?P<project>[a-z0-9_\-.]+)\.googlecode\.com/(git|hg|svn)(?P<path>/.*)?$`,
+		check: oldGoogleCode,
+	},
+
+	// Github
+	{
+		prefix: "github.com/",
+		re:     `^(?P<root>github\.com/[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+)(/[A-Za-z0-9_.\-]+)*$`,
+		vcs:    "git",
+		repo:   "https://{root}",
+		check:  noVCSSuffix,
+	},
+
+	// Bitbucket
+	{
+		prefix: "bitbucket.org/",
+		re:     `^(?P<root>bitbucket\.org/(?P<bitname>[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+))(/[A-Za-z0-9_.\-]+)*$`,
+		repo:   "https://{root}",
+		check:  bitbucketVCS,
+	},
+
+	// Launchpad
+	{
+		prefix: "launchpad.net/",
+		re:     `^(?P<root>launchpad\.net/((?P<project>[A-Za-z0-9_.\-]+)(?P<series>/[A-Za-z0-9_.\-]+)?|~[A-Za-z0-9_.\-]+/(\+junk|[A-Za-z0-9_.\-]+)/[A-Za-z0-9_.\-]+))(/[A-Za-z0-9_.\-]+)*$`,
+		vcs:    "bzr",
+		repo:   "https://{root}",
+		check:  launchpadVCS,
+	},
+
+	// General syntax for any server.
+	{
+		re:   `^(?P<root>(?P<repo>([a-z0-9.\-]+\.)+[a-z0-9.\-]+(:[0-9]+)?/[A-Za-z0-9_.\-/]*?)\.(?P<vcs>bzr|git|hg|svn))(/[A-Za-z0-9_.\-]+)*$`,
+		ping: true,
+	},
+}
+
+func init() {
+	// fill in cached regexps.
+	// Doing this eagerly discovers invalid regexp syntax
+	// without having to run a command that needs that regexp.
+	for _, srv := range vcsPaths {
+		srv.regexp = regexp.MustCompile(srv.re)
+	}
+}
+
+// noVCSSuffix checks that the repository name does not
+// end in .foo for any version control system foo.
+// The usual culprit is ".git".
+func noVCSSuffix(match map[string]string) error {
+	repo := match["repo"]
+	for _, vcs := range vcsList {
+		if strings.HasSuffix(repo, "."+vcs.cmd) {
+			return fmt.Errorf("invalid version control suffix in %s path", match["prefix"])
+		}
+	}
+	return nil
+}
+
+var googleCheckout = regexp.MustCompile(`id="checkoutcmd">(hg|git|svn)`)
+
+// googleCodeVCS determines the version control system for
+// a code.google.com repository, by scraping the project's
+// /source/checkout page.
+func googleCodeVCS(match map[string]string) error {
+	if err := noVCSSuffix(match); err != nil {
+		return err
+	}
+	data, err := httpGET(expand(match, "https://code.google.com/p/{project}/source/checkout?repo={subrepo}"))
+	if err != nil {
+		return err
+	}
+
+	if m := googleCheckout.FindSubmatch(data); m != nil {
+		if vcs := vcsByCmd(string(m[1])); vcs != nil {
+			// Subversion requires the old URLs.
+			// TODO: Test.
+			if vcs == vcsSvn {
+				if match["subrepo"] != "" {
+					return fmt.Errorf("sub-repositories not supported in Google Code Subversion projects")
+				}
+				match["repo"] = expand(match, "https://{project}.googlecode.com/svn")
+			}
+			match["vcs"] = vcs.cmd
+			return nil
+		}
+	}
+
+	return fmt.Errorf("unable to detect version control system for code.google.com/ path")
+}
+
+// oldGoogleCode is invoked for old-style foo.googlecode.com paths.
+// It prints an error giving the equivalent new path.
+func oldGoogleCode(match map[string]string) error {
+	return fmt.Errorf("invalid Google Code import path: use %s instead",
+		expand(match, "code.google.com/p/{project}{path}"))
+}
+
+// bitbucketVCS determines the version control system for a
+// Bitbucket repository, by using the Bitbucket API.
+func bitbucketVCS(match map[string]string) error {
+	if err := noVCSSuffix(match); err != nil {
+		return err
+	}
+
+	var resp struct {
+		SCM string `json:"scm"`
+	}
+	url := expand(match, "https://api.bitbucket.org/1.0/repositories/{bitname}")
+	data, err := httpGET(url)
+	if err != nil {
+		return err
+	}
+	if err := json.Unmarshal(data, &resp); err != nil {
+		return fmt.Errorf("decoding %s: %v", url, err)
+	}
+
+	if vcsByCmd(resp.SCM) != nil {
+		match["vcs"] = resp.SCM
+		if resp.SCM == "git" {
+			match["repo"] += ".git"
+		}
+		return nil
+	}
+
+	return fmt.Errorf("unable to detect version control system for bitbucket.org/ path")
+}
+
+// launchpadVCS solves the ambiguity for "lp.net/project/foo". In this case,
+// "foo" could be a series name registered in Launchpad with its own branch,
+// and it could also be the name of a directory within the main project
+// branch one level up.
+func launchpadVCS(match map[string]string) error {
+	if match["project"] == "" || match["series"] == "" {
+		return nil
+	}
+	_, err := httpGET(expand(match, "https://code.launchpad.net/{project}{series}/.bzr/branch-format"))
+	if err != nil {
+		match["root"] = expand(match, "launchpad.net/{project}")
+		match["repo"] = expand(match, "https://{root}")
+	}
+	return nil
+}

libgo/go/cmd/go/version.go

@@ -0,0 +1,25 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+)
+
+var cmdVersion = &Command{
+	Run:       runVersion,
+	UsageLine: "version",
+	Short:     "print Go version",
+	Long:      `Version prints the Go version, as reported by runtime.Version.`,
+}
+
+func runVersion(cmd *Command, args []string) {
+	if len(args) != 0 {
+		cmd.Usage()
+	}
+
+	fmt.Printf("go version %s %s/%s\n", runtime.Version(), runtime.GOOS, runtime.GOARCH)
+}

libgo/go/cmd/go/vet.go

@@ -0,0 +1,37 @@
+// Copyright 2011 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.
+
+package main
+
+func init() {
+	addBuildFlagsNX(cmdVet)
+}
+
+var cmdVet = &Command{
+	Run:       runVet,
+	UsageLine: "vet [-n] [-x] [packages]",
+	Short:     "run go tool vet on packages",
+	Long: `
+Vet runs the Go vet command on the packages named by the import paths.
+
+For more about vet, see 'godoc code.google.com/p/go.tools/cmd/vet'.
+For more about specifying packages, see 'go help packages'.
+
+To run the vet tool with specific options, run 'go tool vet'.
+
+The -n flag prints commands that would be executed.
+The -x flag prints commands as they are executed.
+
+See also: go fmt, go fix.
+	`,
+}
+
+func runVet(cmd *Command, args []string) {
+	for _, pkg := range packages(args) {
+		// Use pkg.gofiles instead of pkg.Dir so that
+		// the command only applies to this package,
+		// not to packages in subdirectories.
+		run(tool("vet"), relPaths(stringList(pkg.gofiles, pkg.sfiles)))
+	}
+}

libgo/go/cmd/gofmt/doc.go

@@ -0,0 +1,93 @@
+// 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.
+
+/*
+Gofmt formats Go programs.
+It uses tabs (width = 8) for indentation and blanks for alignment.
+
+Without an explicit path, it processes the standard input.  Given a file,
+it operates on that file; given a directory, it operates on all .go files in
+that directory, recursively.  (Files starting with a period are ignored.)
+By default, gofmt prints the reformatted sources to standard output.
+
+Usage:
+	gofmt [flags] [path ...]
+
+The flags are:
+	-d
+		Do not print reformatted sources to standard output.
+		If a file's formatting is different than gofmt's, print diffs
+		to standard output.
+	-e
+		Print all (including spurious) errors.
+	-l
+		Do not print reformatted sources to standard output.
+		If a file's formatting is different from gofmt's, print its name
+		to standard output.
+	-r rule
+		Apply the rewrite rule to the source before reformatting.
+	-s
+		Try to simplify code (after applying the rewrite rule, if any).
+	-w
+		Do not print reformatted sources to standard output.
+		If a file's formatting is different from gofmt's, overwrite it
+		with gofmt's version.
+
+Debugging support:
+	-cpuprofile filename
+		Write cpu profile to the specified file.
+
+
+The rewrite rule specified with the -r flag must be a string of the form:
+
+	pattern -> replacement
+
+Both pattern and replacement must be valid Go expressions.
+In the pattern, single-character lowercase identifiers serve as
+wildcards matching arbitrary sub-expressions; those expressions
+will be substituted for the same identifiers in the replacement.
+
+When gofmt reads from standard input, it accepts either a full Go program
+or a program fragment.  A program fragment must be a syntactically
+valid declaration list, statement list, or expression.  When formatting
+such a fragment, gofmt preserves leading indentation as well as leading
+and trailing spaces, so that individual sections of a Go program can be
+formatted by piping them through gofmt.
+
+Examples
+
+To check files for unnecessary parentheses:
+
+	gofmt -r '(a) -> a' -l *.go
+
+To remove the parentheses:
+
+	gofmt -r '(a) -> a' -w *.go
+
+To convert the package tree from explicit slice upper bounds to implicit ones:
+
+	gofmt -r 'α[β:len(α)] -> α[β:]' -w $GOROOT/src/pkg
+
+The simplify command
+
+When invoked with -s gofmt will make the following source transformations where possible.
+
+	An array, slice, or map composite literal of the form:
+		[]T{T{}, T{}}
+	will be simplified to:
+		[]T{{}, {}}
+
+	A slice expression of the form:
+		s[a:len(s)]
+	will be simplified to:
+		s[a:]
+
+	A range of the form:
+		for x, _ = range v {...}
+	will be simplified to:
+		for x = range v {...}
+*/
+package main
+
+// BUG(rsc): The implementation of -r is a bit slow.

libgo/go/cmd/gofmt/gofmt.go

@@ -0,0 +1,344 @@
+// 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.
+
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/printer"
+	"go/scanner"
+	"go/token"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime/pprof"
+	"strings"
+)
+
+var (
+	// main operation modes
+	list        = flag.Bool("l", false, "list files whose formatting differs from gofmt's")
+	write       = flag.Bool("w", false, "write result to (source) file instead of stdout")
+	rewriteRule = flag.String("r", "", "rewrite rule (e.g., 'a[b:len(a)] -> a[b:]')")
+	simplifyAST = flag.Bool("s", false, "simplify code")
+	doDiff      = flag.Bool("d", false, "display diffs instead of rewriting files")
+	allErrors   = flag.Bool("e", false, "report all errors (not just the first 10 on different lines)")
+
+	// debugging
+	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file")
+)
+
+const (
+	tabWidth    = 8
+	printerMode = printer.UseSpaces | printer.TabIndent
+)
+
+var (
+	fileSet    = token.NewFileSet() // per process FileSet
+	exitCode   = 0
+	rewrite    func(*ast.File) *ast.File
+	parserMode parser.Mode
+)
+
+func report(err error) {
+	scanner.PrintError(os.Stderr, err)
+	exitCode = 2
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: gofmt [flags] [path ...]\n")
+	flag.PrintDefaults()
+	os.Exit(2)
+}
+
+func initParserMode() {
+	parserMode = parser.ParseComments
+	if *allErrors {
+		parserMode |= parser.AllErrors
+	}
+}
+
+func isGoFile(f os.FileInfo) bool {
+	// ignore non-Go files
+	name := f.Name()
+	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
+}
+
+// If in == nil, the source is the contents of the file with the given filename.
+func processFile(filename string, in io.Reader, out io.Writer, stdin bool) error {
+	if in == nil {
+		f, err := os.Open(filename)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		in = f
+	}
+
+	src, err := ioutil.ReadAll(in)
+	if err != nil {
+		return err
+	}
+
+	file, adjust, err := parse(fileSet, filename, src, stdin)
+	if err != nil {
+		return err
+	}
+
+	if rewrite != nil {
+		if adjust == nil {
+			file = rewrite(file)
+		} else {
+			fmt.Fprintf(os.Stderr, "warning: rewrite ignored for incomplete programs\n")
+		}
+	}
+
+	ast.SortImports(fileSet, file)
+
+	if *simplifyAST {
+		simplify(file)
+	}
+
+	var buf bytes.Buffer
+	err = (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(&buf, fileSet, file)
+	if err != nil {
+		return err
+	}
+	res := buf.Bytes()
+	if adjust != nil {
+		res = adjust(src, res)
+	}
+
+	if !bytes.Equal(src, res) {
+		// formatting has changed
+		if *list {
+			fmt.Fprintln(out, filename)
+		}
+		if *write {
+			err = ioutil.WriteFile(filename, res, 0)
+			if err != nil {
+				return err
+			}
+		}
+		if *doDiff {
+			data, err := diff(src, res)
+			if err != nil {
+				return fmt.Errorf("computing diff: %s", err)
+			}
+			fmt.Printf("diff %s gofmt/%s\n", filename, filename)
+			out.Write(data)
+		}
+	}
+
+	if !*list && !*write && !*doDiff {
+		_, err = out.Write(res)
+	}
+
+	return err
+}
+
+func visitFile(path string, f os.FileInfo, err error) error {
+	if err == nil && isGoFile(f) {
+		err = processFile(path, nil, os.Stdout, false)
+	}
+	if err != nil {
+		report(err)
+	}
+	return nil
+}
+
+func walkDir(path string) {
+	filepath.Walk(path, visitFile)
+}
+
+func main() {
+	// call gofmtMain in a separate function
+	// so that it can use defer and have them
+	// run before the exit.
+	gofmtMain()
+	os.Exit(exitCode)
+}
+
+func gofmtMain() {
+	flag.Usage = usage
+	flag.Parse()
+
+	if *cpuprofile != "" {
+		f, err := os.Create(*cpuprofile)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "creating cpu profile: %s\n", err)
+			exitCode = 2
+			return
+		}
+		defer f.Close()
+		pprof.StartCPUProfile(f)
+		defer pprof.StopCPUProfile()
+	}
+
+	initParserMode()
+	initRewrite()
+
+	if flag.NArg() == 0 {
+		if err := processFile("<standard input>", os.Stdin, os.Stdout, true); err != nil {
+			report(err)
+		}
+		return
+	}
+
+	for i := 0; i < flag.NArg(); i++ {
+		path := flag.Arg(i)
+		switch dir, err := os.Stat(path); {
+		case err != nil:
+			report(err)
+		case dir.IsDir():
+			walkDir(path)
+		default:
+			if err := processFile(path, nil, os.Stdout, false); err != nil {
+				report(err)
+			}
+		}
+	}
+}
+
+func diff(b1, b2 []byte) (data []byte, err error) {
+	f1, err := ioutil.TempFile("", "gofmt")
+	if err != nil {
+		return
+	}
+	defer os.Remove(f1.Name())
+	defer f1.Close()
+
+	f2, err := ioutil.TempFile("", "gofmt")
+	if err != nil {
+		return
+	}
+	defer os.Remove(f2.Name())
+	defer f2.Close()
+
+	f1.Write(b1)
+	f2.Write(b2)
+
+	data, err = exec.Command("diff", "-u", f1.Name(), f2.Name()).CombinedOutput()
+	if len(data) > 0 {
+		// diff exits with a non-zero status when the files don't match.
+		// Ignore that failure as long as we get output.
+		err = nil
+	}
+	return
+
+}
+
+// parse parses src, which was read from filename,
+// as a Go source file or statement list.
+func parse(fset *token.FileSet, filename string, src []byte, stdin bool) (*ast.File, func(orig, src []byte) []byte, error) {
+	// Try as whole source file.
+	file, err := parser.ParseFile(fset, filename, src, parserMode)
+	if err == nil {
+		return file, nil, nil
+	}
+	// If the error is that the source file didn't begin with a
+	// package line and this is standard input, fall through to
+	// try as a source fragment.  Stop and return on any other error.
+	if !stdin || !strings.Contains(err.Error(), "expected 'package'") {
+		return nil, nil, err
+	}
+
+	// If this is a declaration list, make it a source file
+	// by inserting a package clause.
+	// Insert using a ;, not a newline, so that the line numbers
+	// in psrc match the ones in src.
+	psrc := append([]byte("package p;"), src...)
+	file, err = parser.ParseFile(fset, filename, psrc, parserMode)
+	if err == nil {
+		adjust := func(orig, src []byte) []byte {
+			// Remove the package clause.
+			// Gofmt has turned the ; into a \n.
+			src = src[len("package p\n"):]
+			return matchSpace(orig, src)
+		}
+		return file, adjust, nil
+	}
+	// If the error is that the source file didn't begin with a
+	// declaration, fall through to try as a statement list.
+	// Stop and return on any other error.
+	if !strings.Contains(err.Error(), "expected declaration") {
+		return nil, nil, err
+	}
+
+	// If this is a statement list, make it a source file
+	// by inserting a package clause and turning the list
+	// into a function body.  This handles expressions too.
+	// Insert using a ;, not a newline, so that the line numbers
+	// in fsrc match the ones in src.
+	fsrc := append(append([]byte("package p; func _() {"), src...), '}')
+	file, err = parser.ParseFile(fset, filename, fsrc, parserMode)
+	if err == nil {
+		adjust := func(orig, src []byte) []byte {
+			// Remove the wrapping.
+			// Gofmt has turned the ; into a \n\n.
+			src = src[len("package p\n\nfunc _() {"):]
+			src = src[:len(src)-len("}\n")]
+			// Gofmt has also indented the function body one level.
+			// Remove that indent.
+			src = bytes.Replace(src, []byte("\n\t"), []byte("\n"), -1)
+			return matchSpace(orig, src)
+		}
+		return file, adjust, nil
+	}
+
+	// Failed, and out of options.
+	return nil, nil, err
+}
+
+func cutSpace(b []byte) (before, middle, after []byte) {
+	i := 0
+	for i < len(b) && (b[i] == ' ' || b[i] == '\t' || b[i] == '\n') {
+		i++
+	}
+	j := len(b)
+	for j > 0 && (b[j-1] == ' ' || b[j-1] == '\t' || b[j-1] == '\n') {
+		j--
+	}
+	if i <= j {
+		return b[:i], b[i:j], b[j:]
+	}
+	return nil, nil, b[j:]
+}
+
+// matchSpace reformats src to use the same space context as orig.
+// 1) If orig begins with blank lines, matchSpace inserts them at the beginning of src.
+// 2) matchSpace copies the indentation of the first non-blank line in orig
+//    to every non-blank line in src.
+// 3) matchSpace copies the trailing space from orig and uses it in place
+//   of src's trailing space.
+func matchSpace(orig []byte, src []byte) []byte {
+	before, _, after := cutSpace(orig)
+	i := bytes.LastIndex(before, []byte{'\n'})
+	before, indent := before[:i+1], before[i+1:]
+
+	_, src, _ = cutSpace(src)
+
+	var b bytes.Buffer
+	b.Write(before)
+	for len(src) > 0 {
+		line := src
+		if i := bytes.IndexByte(line, '\n'); i >= 0 {
+			line, src = line[:i+1], line[i+1:]
+		} else {
+			src = nil
+		}
+		if len(line) > 0 && line[0] != '\n' { // not blank
+			b.Write(indent)
+		}
+		b.Write(line)
+	}
+	b.Write(after)
+	return b.Bytes()
+}

libgo/go/cmd/gofmt/gofmt_test.go

@@ -0,0 +1,134 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"bytes"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func runTest(t *testing.T, in, out, flags string) {
+	// process flags
+	*simplifyAST = false
+	*rewriteRule = ""
+	stdin := false
+	for _, flag := range strings.Split(flags, " ") {
+		elts := strings.SplitN(flag, "=", 2)
+		name := elts[0]
+		value := ""
+		if len(elts) == 2 {
+			value = elts[1]
+		}
+		switch name {
+		case "":
+			// no flags
+		case "-r":
+			*rewriteRule = value
+		case "-s":
+			*simplifyAST = true
+		case "-stdin":
+			// fake flag - pretend input is from stdin
+			stdin = true
+		default:
+			t.Errorf("unrecognized flag name: %s", name)
+		}
+	}
+
+	initParserMode()
+	initRewrite()
+
+	var buf bytes.Buffer
+	err := processFile(in, nil, &buf, stdin)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	expected, err := ioutil.ReadFile(out)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if got := buf.Bytes(); !bytes.Equal(got, expected) {
+		t.Errorf("(gofmt %s) != %s (see %s.gofmt)", in, out, in)
+		d, err := diff(expected, got)
+		if err == nil {
+			t.Errorf("%s", d)
+		}
+		if err := ioutil.WriteFile(in+".gofmt", got, 0666); err != nil {
+			t.Error(err)
+		}
+	}
+}
+
+var tests = []struct {
+	in, flags string
+}{
+	{"gofmt.go", ""},
+	{"gofmt_test.go", ""},
+	{"testdata/composites.input", "-s"},
+	{"testdata/slices1.input", "-s"},
+	{"testdata/slices2.input", "-s"},
+	{"testdata/old.input", ""},
+	{"testdata/rewrite1.input", "-r=Foo->Bar"},
+	{"testdata/rewrite2.input", "-r=int->bool"},
+	{"testdata/rewrite3.input", "-r=x->x"},
+	{"testdata/rewrite4.input", "-r=(x)->x"},
+	{"testdata/rewrite5.input", "-r=x+x->2*x"},
+	{"testdata/rewrite6.input", "-r=fun(x)->Fun(x)"},
+	{"testdata/rewrite7.input", "-r=fun(x...)->Fun(x)"},
+	{"testdata/rewrite8.input", "-r=interface{}->int"},
+	{"testdata/stdin*.input", "-stdin"},
+	{"testdata/comments.input", ""},
+	{"testdata/import.input", ""},
+	{"testdata/crlf.input", ""},       // test case for issue 3961; see also TestCRLF
+	{"testdata/typeswitch.input", ""}, // test case for issue 4470
+}
+
+func TestRewrite(t *testing.T) {
+	for _, test := range tests {
+		match, err := filepath.Glob(test.in)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		for _, in := range match {
+			out := in
+			if strings.HasSuffix(in, ".input") {
+				out = in[:len(in)-len(".input")] + ".golden"
+			}
+			runTest(t, in, out, test.flags)
+			if in != out {
+				// Check idempotence.
+				runTest(t, out, out, test.flags)
+			}
+		}
+	}
+}
+
+func TestCRLF(t *testing.T) {
+	const input = "testdata/crlf.input"   // must contain CR/LF's
+	const golden = "testdata/crlf.golden" // must not contain any CR's
+
+	data, err := ioutil.ReadFile(input)
+	if err != nil {
+		t.Error(err)
+	}
+	if bytes.Index(data, []byte("\r\n")) < 0 {
+		t.Errorf("%s contains no CR/LF's", input)
+	}
+
+	data, err = ioutil.ReadFile(golden)
+	if err != nil {
+		t.Error(err)
+	}
+	if bytes.Index(data, []byte("\r")) >= 0 {
+		t.Errorf("%s contains CR's", golden)
+	}
+}

libgo/go/cmd/gofmt/long_test.go

@@ -0,0 +1,159 @@
+// Copyright 2011 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.
+
+// This test applies gofmt to all Go files under -root.
+// To test specific files provide a list of comma-separated
+// filenames via the -files flag: go test -files=gofmt.go .
+
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/printer"
+	"go/token"
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+var (
+	root    = flag.String("root", runtime.GOROOT(), "test root directory")
+	files   = flag.String("files", "", "comma-separated list of files to test")
+	ngo     = flag.Int("n", runtime.NumCPU(), "number of goroutines used")
+	verbose = flag.Bool("verbose", false, "verbose mode")
+	nfiles  int // number of files processed
+)
+
+func gofmt(fset *token.FileSet, filename string, src *bytes.Buffer) error {
+	f, _, err := parse(fset, filename, src.Bytes(), false)
+	if err != nil {
+		return err
+	}
+	ast.SortImports(fset, f)
+	src.Reset()
+	return (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(src, fset, f)
+}
+
+func testFile(t *testing.T, b1, b2 *bytes.Buffer, filename string) {
+	// open file
+	f, err := os.Open(filename)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	// read file
+	b1.Reset()
+	_, err = io.Copy(b1, f)
+	f.Close()
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	// exclude files w/ syntax errors (typically test cases)
+	fset := token.NewFileSet()
+	if _, _, err = parse(fset, filename, b1.Bytes(), false); err != nil {
+		if *verbose {
+			fmt.Fprintf(os.Stderr, "ignoring %s\n", err)
+		}
+		return
+	}
+
+	// gofmt file
+	if err = gofmt(fset, filename, b1); err != nil {
+		t.Errorf("1st gofmt failed: %v", err)
+		return
+	}
+
+	// make a copy of the result
+	b2.Reset()
+	b2.Write(b1.Bytes())
+
+	// gofmt result again
+	if err = gofmt(fset, filename, b2); err != nil {
+		t.Errorf("2nd gofmt failed: %v", err)
+		return
+	}
+
+	// the first and 2nd result should be identical
+	if !bytes.Equal(b1.Bytes(), b2.Bytes()) {
+		t.Errorf("gofmt %s not idempotent", filename)
+	}
+}
+
+func testFiles(t *testing.T, filenames <-chan string, done chan<- int) {
+	b1 := new(bytes.Buffer)
+	b2 := new(bytes.Buffer)
+	for filename := range filenames {
+		testFile(t, b1, b2, filename)
+	}
+	done <- 0
+}
+
+func genFilenames(t *testing.T, filenames chan<- string) {
+	defer close(filenames)
+
+	handleFile := func(filename string, fi os.FileInfo, err error) error {
+		if err != nil {
+			t.Error(err)
+			return nil
+		}
+		if isGoFile(fi) {
+			filenames <- filename
+			nfiles++
+		}
+		return nil
+	}
+
+	// test Go files provided via -files, if any
+	if *files != "" {
+		for _, filename := range strings.Split(*files, ",") {
+			fi, err := os.Stat(filename)
+			handleFile(filename, fi, err)
+		}
+		return // ignore files under -root
+	}
+
+	// otherwise, test all Go files under *root
+	filepath.Walk(*root, handleFile)
+}
+
+func TestAll(t *testing.T) {
+	if testing.Short() {
+		return
+	}
+
+	if *ngo < 1 {
+		*ngo = 1 // make sure test is run
+	}
+	if *verbose {
+		fmt.Printf("running test using %d goroutines\n", *ngo)
+	}
+
+	// generate filenames
+	filenames := make(chan string, 32)
+	go genFilenames(t, filenames)
+
+	// launch test goroutines
+	done := make(chan int)
+	for i := 0; i < *ngo; i++ {
+		go testFiles(t, filenames, done)
+	}
+
+	// wait for all test goroutines to complete
+	for i := 0; i < *ngo; i++ {
+		<-done
+	}
+
+	if *verbose {
+		fmt.Printf("processed %d files\n", nfiles)
+	}
+}

libgo/go/cmd/gofmt/rewrite.go

@@ -0,0 +1,306 @@
+// 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.
+
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"reflect"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+func initRewrite() {
+	if *rewriteRule == "" {
+		rewrite = nil // disable any previous rewrite
+		return
+	}
+	f := strings.Split(*rewriteRule, "->")
+	if len(f) != 2 {
+		fmt.Fprintf(os.Stderr, "rewrite rule must be of the form 'pattern -> replacement'\n")
+		os.Exit(2)
+	}
+	pattern := parseExpr(f[0], "pattern")
+	replace := parseExpr(f[1], "replacement")
+	rewrite = func(p *ast.File) *ast.File { return rewriteFile(pattern, replace, p) }
+}
+
+// parseExpr parses s as an expression.
+// It might make sense to expand this to allow statement patterns,
+// but there are problems with preserving formatting and also
+// with what a wildcard for a statement looks like.
+func parseExpr(s, what string) ast.Expr {
+	x, err := parser.ParseExpr(s)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "parsing %s %s at %s\n", what, s, err)
+		os.Exit(2)
+	}
+	return x
+}
+
+// Keep this function for debugging.
+/*
+func dump(msg string, val reflect.Value) {
+	fmt.Printf("%s:\n", msg)
+	ast.Print(fileSet, val.Interface())
+	fmt.Println()
+}
+*/
+
+// rewriteFile applies the rewrite rule 'pattern -> replace' to an entire file.
+func rewriteFile(pattern, replace ast.Expr, p *ast.File) *ast.File {
+	cmap := ast.NewCommentMap(fileSet, p, p.Comments)
+	m := make(map[string]reflect.Value)
+	pat := reflect.ValueOf(pattern)
+	repl := reflect.ValueOf(replace)
+
+	var rewriteVal func(val reflect.Value) reflect.Value
+	rewriteVal = func(val reflect.Value) reflect.Value {
+		// don't bother if val is invalid to start with
+		if !val.IsValid() {
+			return reflect.Value{}
+		}
+		for k := range m {
+			delete(m, k)
+		}
+		val = apply(rewriteVal, val)
+		if match(m, pat, val) {
+			val = subst(m, repl, reflect.ValueOf(val.Interface().(ast.Node).Pos()))
+		}
+		return val
+	}
+
+	r := apply(rewriteVal, reflect.ValueOf(p)).Interface().(*ast.File)
+	r.Comments = cmap.Filter(r).Comments() // recreate comments list
+	return r
+}
+
+// set is a wrapper for x.Set(y); it protects the caller from panics if x cannot be changed to y.
+func set(x, y reflect.Value) {
+	// don't bother if x cannot be set or y is invalid
+	if !x.CanSet() || !y.IsValid() {
+		return
+	}
+	defer func() {
+		if x := recover(); x != nil {
+			if s, ok := x.(string); ok &&
+				(strings.Contains(s, "type mismatch") || strings.Contains(s, "not assignable")) {
+				// x cannot be set to y - ignore this rewrite
+				return
+			}
+			panic(x)
+		}
+	}()
+	x.Set(y)
+}
+
+// Values/types for special cases.
+var (
+	objectPtrNil = reflect.ValueOf((*ast.Object)(nil))
+	scopePtrNil  = reflect.ValueOf((*ast.Scope)(nil))
+
+	identType     = reflect.TypeOf((*ast.Ident)(nil))
+	objectPtrType = reflect.TypeOf((*ast.Object)(nil))
+	positionType  = reflect.TypeOf(token.NoPos)
+	callExprType  = reflect.TypeOf((*ast.CallExpr)(nil))
+	scopePtrType  = reflect.TypeOf((*ast.Scope)(nil))
+)
+
+// apply replaces each AST field x in val with f(x), returning val.
+// To avoid extra conversions, f operates on the reflect.Value form.
+func apply(f func(reflect.Value) reflect.Value, val reflect.Value) reflect.Value {
+	if !val.IsValid() {
+		return reflect.Value{}
+	}
+
+	// *ast.Objects introduce cycles and are likely incorrect after
+	// rewrite; don't follow them but replace with nil instead
+	if val.Type() == objectPtrType {
+		return objectPtrNil
+	}
+
+	// similarly for scopes: they are likely incorrect after a rewrite;
+	// replace them with nil
+	if val.Type() == scopePtrType {
+		return scopePtrNil
+	}
+
+	switch v := reflect.Indirect(val); v.Kind() {
+	case reflect.Slice:
+		for i := 0; i < v.Len(); i++ {
+			e := v.Index(i)
+			set(e, f(e))
+		}
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			e := v.Field(i)
+			set(e, f(e))
+		}
+	case reflect.Interface:
+		e := v.Elem()
+		set(v, f(e))
+	}
+	return val
+}
+
+func isWildcard(s string) bool {
+	rune, size := utf8.DecodeRuneInString(s)
+	return size == len(s) && unicode.IsLower(rune)
+}
+
+// match returns true if pattern matches val,
+// recording wildcard submatches in m.
+// If m == nil, match checks whether pattern == val.
+func match(m map[string]reflect.Value, pattern, val reflect.Value) bool {
+	// Wildcard matches any expression.  If it appears multiple
+	// times in the pattern, it must match the same expression
+	// each time.
+	if m != nil && pattern.IsValid() && pattern.Type() == identType {
+		name := pattern.Interface().(*ast.Ident).Name
+		if isWildcard(name) && val.IsValid() {
+			// wildcards only match valid (non-nil) expressions.
+			if _, ok := val.Interface().(ast.Expr); ok && !val.IsNil() {
+				if old, ok := m[name]; ok {
+					return match(nil, old, val)
+				}
+				m[name] = val
+				return true
+			}
+		}
+	}
+
+	// Otherwise, pattern and val must match recursively.
+	if !pattern.IsValid() || !val.IsValid() {
+		return !pattern.IsValid() && !val.IsValid()
+	}
+	if pattern.Type() != val.Type() {
+		return false
+	}
+
+	// Special cases.
+	switch pattern.Type() {
+	case identType:
+		// For identifiers, only the names need to match
+		// (and none of the other *ast.Object information).
+		// This is a common case, handle it all here instead
+		// of recursing down any further via reflection.
+		p := pattern.Interface().(*ast.Ident)
+		v := val.Interface().(*ast.Ident)
+		return p == nil && v == nil || p != nil && v != nil && p.Name == v.Name
+	case objectPtrType, positionType:
+		// object pointers and token positions always match
+		return true
+	case callExprType:
+		// For calls, the Ellipsis fields (token.Position) must
+		// match since that is how f(x) and f(x...) are different.
+		// Check them here but fall through for the remaining fields.
+		p := pattern.Interface().(*ast.CallExpr)
+		v := val.Interface().(*ast.CallExpr)
+		if p.Ellipsis.IsValid() != v.Ellipsis.IsValid() {
+			return false
+		}
+	}
+
+	p := reflect.Indirect(pattern)
+	v := reflect.Indirect(val)
+	if !p.IsValid() || !v.IsValid() {
+		return !p.IsValid() && !v.IsValid()
+	}
+
+	switch p.Kind() {
+	case reflect.Slice:
+		if p.Len() != v.Len() {
+			return false
+		}
+		for i := 0; i < p.Len(); i++ {
+			if !match(m, p.Index(i), v.Index(i)) {
+				return false
+			}
+		}
+		return true
+
+	case reflect.Struct:
+		if p.NumField() != v.NumField() {
+			return false
+		}
+		for i := 0; i < p.NumField(); i++ {
+			if !match(m, p.Field(i), v.Field(i)) {
+				return false
+			}
+		}
+		return true
+
+	case reflect.Interface:
+		return match(m, p.Elem(), v.Elem())
+	}
+
+	// Handle token integers, etc.
+	return p.Interface() == v.Interface()
+}
+
+// subst returns a copy of pattern with values from m substituted in place
+// of wildcards and pos used as the position of tokens from the pattern.
+// if m == nil, subst returns a copy of pattern and doesn't change the line
+// number information.
+func subst(m map[string]reflect.Value, pattern reflect.Value, pos reflect.Value) reflect.Value {
+	if !pattern.IsValid() {
+		return reflect.Value{}
+	}
+
+	// Wildcard gets replaced with map value.
+	if m != nil && pattern.Type() == identType {
+		name := pattern.Interface().(*ast.Ident).Name
+		if isWildcard(name) {
+			if old, ok := m[name]; ok {
+				return subst(nil, old, reflect.Value{})
+			}
+		}
+	}
+
+	if pos.IsValid() && pattern.Type() == positionType {
+		// use new position only if old position was valid in the first place
+		if old := pattern.Interface().(token.Pos); !old.IsValid() {
+			return pattern
+		}
+		return pos
+	}
+
+	// Otherwise copy.
+	switch p := pattern; p.Kind() {
+	case reflect.Slice:
+		v := reflect.MakeSlice(p.Type(), p.Len(), p.Len())
+		for i := 0; i < p.Len(); i++ {
+			v.Index(i).Set(subst(m, p.Index(i), pos))
+		}
+		return v
+
+	case reflect.Struct:
+		v := reflect.New(p.Type()).Elem()
+		for i := 0; i < p.NumField(); i++ {
+			v.Field(i).Set(subst(m, p.Field(i), pos))
+		}
+		return v
+
+	case reflect.Ptr:
+		v := reflect.New(p.Type()).Elem()
+		if elem := p.Elem(); elem.IsValid() {
+			v.Set(subst(m, elem, pos).Addr())
+		}
+		return v
+
+	case reflect.Interface:
+		v := reflect.New(p.Type()).Elem()
+		if elem := p.Elem(); elem.IsValid() {
+			v.Set(subst(m, elem, pos))
+		}
+		return v
+	}
+
+	return pattern
+}

libgo/go/cmd/gofmt/simplify.go

@@ -0,0 +1,121 @@
+// Copyright 2010 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.
+
+package main
+
+import (
+	"go/ast"
+	"go/token"
+	"reflect"
+)
+
+type simplifier struct {
+	hasDotImport bool // package file contains: import . "some/import/path"
+}
+
+func (s *simplifier) Visit(node ast.Node) ast.Visitor {
+	switch n := node.(type) {
+	case *ast.CompositeLit:
+		// array, slice, and map composite literals may be simplified
+		outer := n
+		var eltType ast.Expr
+		switch typ := outer.Type.(type) {
+		case *ast.ArrayType:
+			eltType = typ.Elt
+		case *ast.MapType:
+			eltType = typ.Value
+		}
+
+		if eltType != nil {
+			typ := reflect.ValueOf(eltType)
+			for i, x := range outer.Elts {
+				px := &outer.Elts[i]
+				// look at value of indexed/named elements
+				if t, ok := x.(*ast.KeyValueExpr); ok {
+					x = t.Value
+					px = &t.Value
+				}
+				ast.Walk(s, x) // simplify x
+				// if the element is a composite literal and its literal type
+				// matches the outer literal's element type exactly, the inner
+				// literal type may be omitted
+				if inner, ok := x.(*ast.CompositeLit); ok {
+					if match(nil, typ, reflect.ValueOf(inner.Type)) {
+						inner.Type = nil
+					}
+				}
+				// if the outer literal's element type is a pointer type *T
+				// and the element is & of a composite literal of type T,
+				// the inner &T may be omitted.
+				if ptr, ok := eltType.(*ast.StarExpr); ok {
+					if addr, ok := x.(*ast.UnaryExpr); ok && addr.Op == token.AND {
+						if inner, ok := addr.X.(*ast.CompositeLit); ok {
+							if match(nil, reflect.ValueOf(ptr.X), reflect.ValueOf(inner.Type)) {
+								inner.Type = nil // drop T
+								*px = inner      // drop &
+							}
+						}
+					}
+				}
+			}
+
+			// node was simplified - stop walk (there are no subnodes to simplify)
+			return nil
+		}
+
+	case *ast.SliceExpr:
+		// a slice expression of the form: s[a:len(s)]
+		// can be simplified to: s[a:]
+		// if s is "simple enough" (for now we only accept identifiers)
+		if s.hasDotImport {
+			// if dot imports are present, we cannot be certain that an
+			// unresolved "len" identifier refers to the predefined len()
+			break
+		}
+		if s, _ := n.X.(*ast.Ident); s != nil && s.Obj != nil {
+			// the array/slice object is a single, resolved identifier
+			if call, _ := n.High.(*ast.CallExpr); call != nil && len(call.Args) == 1 && !call.Ellipsis.IsValid() {
+				// the high expression is a function call with a single argument
+				if fun, _ := call.Fun.(*ast.Ident); fun != nil && fun.Name == "len" && fun.Obj == nil {
+					// the function called is "len" and it is not locally defined; and
+					// because we don't have dot imports, it must be the predefined len()
+					if arg, _ := call.Args[0].(*ast.Ident); arg != nil && arg.Obj == s.Obj {
+						// the len argument is the array/slice object
+						n.High = nil
+					}
+				}
+			}
+		}
+		// Note: We could also simplify slice expressions of the form s[0:b] to s[:b]
+		//       but we leave them as is since sometimes we want to be very explicit
+		//       about the lower bound.
+		// An example where the 0 helps:
+		//       x, y, z := b[0:2], b[2:4], b[4:6]
+		// An example where it does not:
+		//       x, y := b[:n], b[n:]
+
+	case *ast.RangeStmt:
+		// a range of the form: for x, _ = range v {...}
+		// can be simplified to: for x = range v {...}
+		if ident, _ := n.Value.(*ast.Ident); ident != nil && ident.Name == "_" {
+			n.Value = nil
+		}
+	}
+
+	return s
+}
+
+func simplify(f *ast.File) {
+	var s simplifier
+
+	// determine if f contains dot imports
+	for _, imp := range f.Imports {
+		if imp.Name != nil && imp.Name.Name == "." {
+			s.hasDotImport = true
+			break
+		}
+	}
+
+	ast.Walk(&s, f)
+}

libgo/go/cmd/gofmt/testdata/comments.golden

@@ -0,0 +1,9 @@
+package main
+
+func main() {}
+
+// comment here
+
+func f() {}
+
+//line foo.go:1

libgo/go/cmd/gofmt/testdata/comments.input

@@ -0,0 +1,9 @@
+package main
+
+func main() {}
+
+// comment here
+
+func f() {}
+
+//line foo.go:1

libgo/go/cmd/gofmt/testdata/composites.golden

@@ -0,0 +1,202 @@
+package P
+
+type T struct {
+	x, y int
+}
+
+var _ = [42]T{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = [...]T{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = []T{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = []T{
+	{},
+	10: {1, 2},
+	20: {3, 4},
+}
+
+var _ = []struct {
+	x, y int
+}{
+	{},
+	10: {1, 2},
+	20: {3, 4},
+}
+
+var _ = []interface{}{
+	T{},
+	10: T{1, 2},
+	20: T{3, 4},
+}
+
+var _ = [][]int{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = [][]int{
+	([]int{}),
+	([]int{1, 2}),
+	{3, 4},
+}
+
+var _ = [][][]int{
+	{},
+	{
+		{},
+		{0, 1, 2, 3},
+		{4, 5},
+	},
+}
+
+var _ = map[string]T{
+	"foo": {},
+	"bar": {1, 2},
+	"bal": {3, 4},
+}
+
+var _ = map[string]struct {
+	x, y int
+}{
+	"foo": {},
+	"bar": {1, 2},
+	"bal": {3, 4},
+}
+
+var _ = map[string]interface{}{
+	"foo": T{},
+	"bar": T{1, 2},
+	"bal": T{3, 4},
+}
+
+var _ = map[string][]int{
+	"foo": {},
+	"bar": {1, 2},
+	"bal": {3, 4},
+}
+
+var _ = map[string][]int{
+	"foo": ([]int{}),
+	"bar": ([]int{1, 2}),
+	"bal": {3, 4},
+}
+
+// from exp/4s/data.go
+var pieces4 = []Piece{
+	{0, 0, Point{4, 1}, []Point{{0, 0}, {1, 0}, {1, 0}, {1, 0}}, nil, nil},
+	{1, 0, Point{1, 4}, []Point{{0, 0}, {0, 1}, {0, 1}, {0, 1}}, nil, nil},
+	{2, 0, Point{4, 1}, []Point{{0, 0}, {1, 0}, {1, 0}, {1, 0}}, nil, nil},
+	{3, 0, Point{1, 4}, []Point{{0, 0}, {0, 1}, {0, 1}, {0, 1}}, nil, nil},
+}
+
+var _ = [42]*T{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = [...]*T{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = []*T{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = []*T{
+	{},
+	10: {1, 2},
+	20: {3, 4},
+}
+
+var _ = []*struct {
+	x, y int
+}{
+	{},
+	10: {1, 2},
+	20: {3, 4},
+}
+
+var _ = []interface{}{
+	&T{},
+	10: &T{1, 2},
+	20: &T{3, 4},
+}
+
+var _ = []*[]int{
+	{},
+	{1, 2},
+	{3, 4},
+}
+
+var _ = []*[]int{
+	(&[]int{}),
+	(&[]int{1, 2}),
+	{3, 4},
+}
+
+var _ = []*[]*[]int{
+	{},
+	{
+		{},
+		{0, 1, 2, 3},
+		{4, 5},
+	},
+}
+
+var _ = map[string]*T{
+	"foo": {},
+	"bar": {1, 2},
+	"bal": {3, 4},
+}
+
+var _ = map[string]*struct {
+	x, y int
+}{
+	"foo": {},
+	"bar": {1, 2},
+	"bal": {3, 4},
+}
+
+var _ = map[string]interface{}{
+	"foo": &T{},
+	"bar": &T{1, 2},
+	"bal": &T{3, 4},
+}
+
+var _ = map[string]*[]int{
+	"foo": {},
+	"bar": {1, 2},
+	"bal": {3, 4},
+}
+
+var _ = map[string]*[]int{
+	"foo": (&[]int{}),
+	"bar": (&[]int{1, 2}),
+	"bal": {3, 4},
+}
+
+var pieces4 = []*Piece{
+	{0, 0, Point{4, 1}, []Point{{0, 0}, {1, 0}, {1, 0}, {1, 0}}, nil, nil},
+	{1, 0, Point{1, 4}, []Point{{0, 0}, {0, 1}, {0, 1}, {0, 1}}, nil, nil},
+	{2, 0, Point{4, 1}, []Point{{0, 0}, {1, 0}, {1, 0}, {1, 0}}, nil, nil},
+	{3, 0, Point{1, 4}, []Point{{0, 0}, {0, 1}, {0, 1}, {0, 1}}, nil, nil},
+}

libgo/go/cmd/gofmt/testdata/composites.input

@@ -0,0 +1,202 @@
+package P
+
+type T struct {
+	x, y int
+}
+
+var _ = [42]T{
+	T{},
+	T{1, 2},
+	T{3, 4},
+}
+
+var _ = [...]T{
+	T{},
+	T{1, 2},
+	T{3, 4},
+}
+
+var _ = []T{
+	T{},
+	T{1, 2},
+	T{3, 4},
+}
+
+var _ = []T{
+	T{},
+	10: T{1, 2},
+	20: T{3, 4},
+}
+
+var _ = []struct {
+	x, y int
+}{
+	struct{ x, y int }{},
+	10: struct{ x, y int }{1, 2},
+	20: struct{ x, y int }{3, 4},
+}
+
+var _ = []interface{}{
+	T{},
+	10: T{1, 2},
+	20: T{3, 4},
+}
+
+var _ = [][]int{
+	[]int{},
+	[]int{1, 2},
+	[]int{3, 4},
+}
+
+var _ = [][]int{
+	([]int{}),
+	([]int{1, 2}),
+	[]int{3, 4},
+}
+
+var _ = [][][]int{
+	[][]int{},
+	[][]int{
+		[]int{},
+		[]int{0, 1, 2, 3},
+		[]int{4, 5},
+	},
+}
+
+var _ = map[string]T{
+	"foo": T{},
+	"bar": T{1, 2},
+	"bal": T{3, 4},
+}
+
+var _ = map[string]struct {
+	x, y int
+}{
+	"foo": struct{ x, y int }{},
+	"bar": struct{ x, y int }{1, 2},
+	"bal": struct{ x, y int }{3, 4},
+}
+
+var _ = map[string]interface{}{
+	"foo": T{},
+	"bar": T{1, 2},
+	"bal": T{3, 4},
+}
+
+var _ = map[string][]int{
+	"foo": []int{},
+	"bar": []int{1, 2},
+	"bal": []int{3, 4},
+}
+
+var _ = map[string][]int{
+	"foo": ([]int{}),
+	"bar": ([]int{1, 2}),
+	"bal": []int{3, 4},
+}
+
+// from exp/4s/data.go
+var pieces4 = []Piece{
+	Piece{0, 0, Point{4, 1}, []Point{Point{0, 0}, Point{1, 0}, Point{1, 0}, Point{1, 0}}, nil, nil},
+	Piece{1, 0, Point{1, 4}, []Point{Point{0, 0}, Point{0, 1}, Point{0, 1}, Point{0, 1}}, nil, nil},
+	Piece{2, 0, Point{4, 1}, []Point{Point{0, 0}, Point{1, 0}, Point{1, 0}, Point{1, 0}}, nil, nil},
+	Piece{3, 0, Point{1, 4}, []Point{Point{0, 0}, Point{0, 1}, Point{0, 1}, Point{0, 1}}, nil, nil},
+}
+
+var _ = [42]*T{
+	&T{},
+	&T{1, 2},
+	&T{3, 4},
+}
+
+var _ = [...]*T{
+	&T{},
+	&T{1, 2},
+	&T{3, 4},
+}
+
+var _ = []*T{
+	&T{},
+	&T{1, 2},
+	&T{3, 4},
+}
+
+var _ = []*T{
+	&T{},
+	10: &T{1, 2},
+	20: &T{3, 4},
+}
+
+var _ = []*struct {
+	x, y int
+}{
+	&struct{ x, y int }{},
+	10: &struct{ x, y int }{1, 2},
+	20: &struct{ x, y int }{3, 4},
+}
+
+var _ = []interface{}{
+	&T{},
+	10: &T{1, 2},
+	20: &T{3, 4},
+}
+
+var _ = []*[]int{
+	&[]int{},
+	&[]int{1, 2},
+	&[]int{3, 4},
+}
+
+var _ = []*[]int{
+	(&[]int{}),
+	(&[]int{1, 2}),
+	&[]int{3, 4},
+}
+
+var _ = []*[]*[]int{
+	&[]*[]int{},
+	&[]*[]int{
+		&[]int{},
+		&[]int{0, 1, 2, 3},
+		&[]int{4, 5},
+	},
+}
+
+var _ = map[string]*T{
+	"foo": &T{},
+	"bar": &T{1, 2},
+	"bal": &T{3, 4},
+}
+
+var _ = map[string]*struct {
+	x, y int
+}{
+	"foo": &struct{ x, y int }{},
+	"bar": &struct{ x, y int }{1, 2},
+	"bal": &struct{ x, y int }{3, 4},
+}
+
+var _ = map[string]interface{}{
+	"foo": &T{},
+	"bar": &T{1, 2},
+	"bal": &T{3, 4},
+}
+
+var _ = map[string]*[]int{
+	"foo": &[]int{},
+	"bar": &[]int{1, 2},
+	"bal": &[]int{3, 4},
+}
+
+var _ = map[string]*[]int{
+	"foo": (&[]int{}),
+	"bar": (&[]int{1, 2}),
+	"bal": &[]int{3, 4},
+}
+
+var pieces4 = []*Piece{
+	&Piece{0, 0, Point{4, 1}, []Point{Point{0, 0}, Point{1, 0}, Point{1, 0}, Point{1, 0}}, nil, nil},
+	&Piece{1, 0, Point{1, 4}, []Point{Point{0, 0}, Point{0, 1}, Point{0, 1}, Point{0, 1}}, nil, nil},
+	&Piece{2, 0, Point{4, 1}, []Point{Point{0, 0}, Point{1, 0}, Point{1, 0}, Point{1, 0}}, nil, nil},
+	&Piece{3, 0, Point{1, 4}, []Point{Point{0, 0}, Point{0, 1}, Point{0, 1}, Point{0, 1}}, nil, nil},
+}

libgo/go/cmd/gofmt/testdata/crlf.golden

@@ -0,0 +1,12 @@
+/*
+	Source containing CR/LF line endings.
+	The gofmt'ed output must only have LF
+	line endings.
+*/
+package main
+
+func main() {
+	// line comment
+	println("hello, world!") // another line comment
+	println()
+}

libgo/go/cmd/gofmt/testdata/crlf.input

@@ -0,0 +1,12 @@
+/*
+	Source containing CR/LF line endings.
+	The gofmt'ed output must only have LF
+	line endings.
+*/
+package main
+
+func main() {
+	// line comment
+	println("hello, world!") // another line comment
+	println()
+}

libgo/go/cmd/gofmt/testdata/import.golden

@@ -0,0 +1,126 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"math"
+)
+
+import (
+	"fmt"
+
+	"math"
+
+	"log"
+
+	"errors"
+
+	"io"
+)
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"math"
+
+	"fmt"
+
+	"math"
+
+	"log"
+
+	"errors"
+
+	"io"
+)
+
+import (
+	// a block with comments
+	"errors"
+	"fmt" // for Printf
+	"io"  // for Reader
+	"log" // for Fatal
+	"math"
+)
+
+import (
+	"fmt" // for Printf
+
+	"math"
+
+	"log" // for Fatal
+
+	"errors"
+
+	"io" // for Reader
+)
+
+import (
+	// for Printf
+	"fmt"
+
+	"math"
+
+	// for Fatal
+	"log"
+
+	"errors"
+
+	// for Reader
+	"io"
+)
+
+import (
+	"errors"
+	"fmt" // for Printf
+	"io"  // for Reader
+	"log" // for Fatal
+	"math"
+
+	"fmt" // for Printf
+
+	"math"
+
+	"log" // for Fatal
+
+	"errors"
+
+	"io" // for Reader
+)
+
+import (
+	"fmt" // for Printf
+
+	"errors"
+	"io"  // for Reader
+	"log" // for Fatal
+	"math"
+
+	"errors"
+	"fmt" // for Printf
+	"io"  // for Reader
+	"log" // for Fatal
+	"math"
+)
+
+// Test deduping and extended sorting
+import (
+	a "A" // aA
+	b "A" // bA1
+	b "A" // bA2
+	"B"   // B
+	. "B" // .B
+	_ "B" // _b
+	"C"
+	a "D" // aD
+)
+
+import (
+	"dedup_by_group"
+
+	"dedup_by_group"
+)

libgo/go/cmd/gofmt/testdata/import.input

@@ -0,0 +1,131 @@
+package main
+
+import (
+	"fmt"
+	"math"
+	"log"
+	"errors"
+	"io"
+)
+
+import (
+	"fmt"
+
+	"math"
+
+	"log"
+
+	"errors"
+
+	"io"
+)
+
+import (
+	"fmt"
+	"math"
+	"log"
+	"errors"
+	"io"
+
+	"fmt"
+
+	"math"
+
+	"log"
+
+	"errors"
+
+	"io"
+)
+
+import (
+	// a block with comments
+	"fmt" // for Printf
+	"math"
+	"log" // for Fatal
+	"errors"
+	"io" // for Reader
+)
+
+import (
+	"fmt" // for Printf
+
+	"math"
+
+	"log" // for Fatal
+
+	"errors"
+
+	"io" // for Reader
+)
+
+import (
+	// for Printf
+	"fmt"
+
+	"math"
+
+	// for Fatal
+	"log"
+
+	"errors"
+
+	// for Reader
+	"io"
+)
+
+import (
+	"fmt" // for Printf
+	"math"
+	"log" // for Fatal
+	"errors"
+	"io" // for Reader
+
+	"fmt" // for Printf
+
+	"math"
+
+	"log" // for Fatal
+
+	"errors"
+
+	"io" // for Reader
+)
+
+import (
+	"fmt" // for Printf
+
+	"math"
+	"log" // for Fatal
+	"errors"
+	"io" // for Reader
+
+	"fmt" // for Printf
+	"math"
+	"log" // for Fatal
+	"errors"
+	"io" // for Reader
+)
+
+// Test deduping and extended sorting
+import (
+	"B" // B
+	a "A" // aA
+	b "A" // bA2
+	b "A" // bA1
+	. "B" // .B
+	. "B"
+	"C"
+	"C"
+	"C"
+	a "D" // aD
+	"B"
+	_ "B" // _b
+)
+
+import (
+	"dedup_by_group"
+	"dedup_by_group"
+
+	"dedup_by_group"
+)

libgo/go/cmd/gofmt/testdata/old.golden

@@ -0,0 +1,9 @@
+package P
+
+func f() {
+	if x {
+		y
+	} else {
+		z
+	}
+}

libgo/go/cmd/gofmt/testdata/old.input

@@ -0,0 +1,8 @@
+package P
+
+func f() {
+	if x {
+		y
+	} else
+		z
+}

libgo/go/cmd/gofmt/testdata/rewrite1.golden

@@ -0,0 +1,12 @@
+// Copyright 2011 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.
+
+package main
+
+type Bar int
+
+func main() {
+	var a Bar
+	println(a)
+}

libgo/go/cmd/gofmt/testdata/rewrite1.input

@@ -0,0 +1,12 @@
+// Copyright 2011 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.
+
+package main
+
+type Foo int
+
+func main() {
+	var a Foo
+	println(a)
+}

libgo/go/cmd/gofmt/testdata/rewrite2.golden

@@ -0,0 +1,10 @@
+// Copyright 2011 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.
+
+package p
+
+// Slices have nil Len values in the corresponding ast.ArrayType
+// node and reflect.NewValue(slice.Len) is an invalid reflect.Value.
+// The rewriter must not crash in that case. Was issue 1696.
+func f() []bool {}

libgo/go/cmd/gofmt/testdata/rewrite2.input

@@ -0,0 +1,10 @@
+// Copyright 2011 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.
+
+package p
+
+// Slices have nil Len values in the corresponding ast.ArrayType
+// node and reflect.NewValue(slice.Len) is an invalid reflect.Value.
+// The rewriter must not crash in that case. Was issue 1696.
+func f() []int {}

libgo/go/cmd/gofmt/testdata/rewrite3.golden

@@ -0,0 +1,12 @@
+// Copyright 2011 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.
+
+package main
+
+// Field tags are *ast.BasicLit nodes that are nil when the tag is
+// absent. These nil nodes must not be mistaken for expressions,
+// the rewriter should not try to dereference them. Was issue 2410.
+type Foo struct {
+	Field int
+}

libgo/go/cmd/gofmt/testdata/rewrite3.input

@@ -0,0 +1,12 @@
+// Copyright 2011 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.
+
+package main
+
+// Field tags are *ast.BasicLit nodes that are nil when the tag is
+// absent. These nil nodes must not be mistaken for expressions,
+// the rewriter should not try to dereference them. Was issue 2410.
+type Foo struct {
+	Field int
+}