Add generated file

This PR adds generated files under pkg/client and vendor folder.

vendor/golang.org/x/tools/go/ast/astutil/enclosing.go

@@ -0,0 +1,627 @@
+// 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.
+
+package astutil
+
+// This file defines utilities for working with source positions.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"sort"
+)
+
+// PathEnclosingInterval returns the node that encloses the source
+// interval [start, end), and all its ancestors up to the AST root.
+//
+// The definition of "enclosing" used by this function considers
+// additional whitespace abutting a node to be enclosed by it.
+// In this example:
+//
+//              z := x + y // add them
+//                   <-A->
+//                  <----B----->
+//
+// the ast.BinaryExpr(+) node is considered to enclose interval B
+// even though its [Pos()..End()) is actually only interval A.
+// This behaviour makes user interfaces more tolerant of imperfect
+// input.
+//
+// This function treats tokens as nodes, though they are not included
+// in the result. e.g. PathEnclosingInterval("+") returns the
+// enclosing ast.BinaryExpr("x + y").
+//
+// If start==end, the 1-char interval following start is used instead.
+//
+// The 'exact' result is true if the interval contains only path[0]
+// and perhaps some adjacent whitespace.  It is false if the interval
+// overlaps multiple children of path[0], or if it contains only
+// interior whitespace of path[0].
+// In this example:
+//
+//              z := x + y // add them
+//                <--C-->     <---E-->
+//                  ^
+//                  D
+//
+// intervals C, D and E are inexact.  C is contained by the
+// z-assignment statement, because it spans three of its children (:=,
+// x, +).  So too is the 1-char interval D, because it contains only
+// interior whitespace of the assignment.  E is considered interior
+// whitespace of the BlockStmt containing the assignment.
+//
+// Precondition: [start, end) both lie within the same file as root.
+// TODO(adonovan): return (nil, false) in this case and remove precond.
+// Requires FileSet; see loader.tokenFileContainsPos.
+//
+// Postcondition: path is never nil; it always contains at least 'root'.
+//
+func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) {
+	// fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging
+
+	// Precondition: node.[Pos..End) and adjoining whitespace contain [start, end).
+	var visit func(node ast.Node) bool
+	visit = func(node ast.Node) bool {
+		path = append(path, node)
+
+		nodePos := node.Pos()
+		nodeEnd := node.End()
+
+		// fmt.Printf("visit(%T, %d, %d)\n", node, nodePos, nodeEnd) // debugging
+
+		// Intersect [start, end) with interval of node.
+		if start < nodePos {
+			start = nodePos
+		}
+		if end > nodeEnd {
+			end = nodeEnd
+		}
+
+		// Find sole child that contains [start, end).
+		children := childrenOf(node)
+		l := len(children)
+		for i, child := range children {
+			// [childPos, childEnd) is unaugmented interval of child.
+			childPos := child.Pos()
+			childEnd := child.End()
+
+			// [augPos, augEnd) is whitespace-augmented interval of child.
+			augPos := childPos
+			augEnd := childEnd
+			if i > 0 {
+				augPos = children[i-1].End() // start of preceding whitespace
+			}
+			if i < l-1 {
+				nextChildPos := children[i+1].Pos()
+				// Does [start, end) lie between child and next child?
+				if start >= augEnd && end <= nextChildPos {
+					return false // inexact match
+				}
+				augEnd = nextChildPos // end of following whitespace
+			}
+
+			// fmt.Printf("\tchild %d: [%d..%d)\tcontains interval [%d..%d)?\n",
+			// 	i, augPos, augEnd, start, end) // debugging
+
+			// Does augmented child strictly contain [start, end)?
+			if augPos <= start && end <= augEnd {
+				_, isToken := child.(tokenNode)
+				return isToken || visit(child)
+			}
+
+			// Does [start, end) overlap multiple children?
+			// i.e. left-augmented child contains start
+			// but LR-augmented child does not contain end.
+			if start < childEnd && end > augEnd {
+				break
+			}
+		}
+
+		// No single child contained [start, end),
+		// so node is the result.  Is it exact?
+
+		// (It's tempting to put this condition before the
+		// child loop, but it gives the wrong result in the
+		// case where a node (e.g. ExprStmt) and its sole
+		// child have equal intervals.)
+		if start == nodePos && end == nodeEnd {
+			return true // exact match
+		}
+
+		return false // inexact: overlaps multiple children
+	}
+
+	if start > end {
+		start, end = end, start
+	}
+
+	if start < root.End() && end > root.Pos() {
+		if start == end {
+			end = start + 1 // empty interval => interval of size 1
+		}
+		exact = visit(root)
+
+		// Reverse the path:
+		for i, l := 0, len(path); i < l/2; i++ {
+			path[i], path[l-1-i] = path[l-1-i], path[i]
+		}
+	} else {
+		// Selection lies within whitespace preceding the
+		// first (or following the last) declaration in the file.
+		// The result nonetheless always includes the ast.File.
+		path = append(path, root)
+	}
+
+	return
+}
+
+// tokenNode is a dummy implementation of ast.Node for a single token.
+// They are used transiently by PathEnclosingInterval but never escape
+// this package.
+//
+type tokenNode struct {
+	pos token.Pos
+	end token.Pos
+}
+
+func (n tokenNode) Pos() token.Pos {
+	return n.pos
+}
+
+func (n tokenNode) End() token.Pos {
+	return n.end
+}
+
+func tok(pos token.Pos, len int) ast.Node {
+	return tokenNode{pos, pos + token.Pos(len)}
+}
+
+// childrenOf returns the direct non-nil children of ast.Node n.
+// It may include fake ast.Node implementations for bare tokens.
+// it is not safe to call (e.g.) ast.Walk on such nodes.
+//
+func childrenOf(n ast.Node) []ast.Node {
+	var children []ast.Node
+
+	// First add nodes for all true subtrees.
+	ast.Inspect(n, func(node ast.Node) bool {
+		if node == n { // push n
+			return true // recur
+		}
+		if node != nil { // push child
+			children = append(children, node)
+		}
+		return false // no recursion
+	})
+
+	// Then add fake Nodes for bare tokens.
+	switch n := n.(type) {
+	case *ast.ArrayType:
+		children = append(children,
+			tok(n.Lbrack, len("[")),
+			tok(n.Elt.End(), len("]")))
+
+	case *ast.AssignStmt:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.BasicLit:
+		children = append(children,
+			tok(n.ValuePos, len(n.Value)))
+
+	case *ast.BinaryExpr:
+		children = append(children, tok(n.OpPos, len(n.Op.String())))
+
+	case *ast.BlockStmt:
+		children = append(children,
+			tok(n.Lbrace, len("{")),
+			tok(n.Rbrace, len("}")))
+
+	case *ast.BranchStmt:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.CallExpr:
+		children = append(children,
+			tok(n.Lparen, len("(")),
+			tok(n.Rparen, len(")")))
+		if n.Ellipsis != 0 {
+			children = append(children, tok(n.Ellipsis, len("...")))
+		}
+
+	case *ast.CaseClause:
+		if n.List == nil {
+			children = append(children,
+				tok(n.Case, len("default")))
+		} else {
+			children = append(children,
+				tok(n.Case, len("case")))
+		}
+		children = append(children, tok(n.Colon, len(":")))
+
+	case *ast.ChanType:
+		switch n.Dir {
+		case ast.RECV:
+			children = append(children, tok(n.Begin, len("<-chan")))
+		case ast.SEND:
+			children = append(children, tok(n.Begin, len("chan<-")))
+		case ast.RECV | ast.SEND:
+			children = append(children, tok(n.Begin, len("chan")))
+		}
+
+	case *ast.CommClause:
+		if n.Comm == nil {
+			children = append(children,
+				tok(n.Case, len("default")))
+		} else {
+			children = append(children,
+				tok(n.Case, len("case")))
+		}
+		children = append(children, tok(n.Colon, len(":")))
+
+	case *ast.Comment:
+		// nop
+
+	case *ast.CommentGroup:
+		// nop
+
+	case *ast.CompositeLit:
+		children = append(children,
+			tok(n.Lbrace, len("{")),
+			tok(n.Rbrace, len("{")))
+
+	case *ast.DeclStmt:
+		// nop
+
+	case *ast.DeferStmt:
+		children = append(children,
+			tok(n.Defer, len("defer")))
+
+	case *ast.Ellipsis:
+		children = append(children,
+			tok(n.Ellipsis, len("...")))
+
+	case *ast.EmptyStmt:
+		// nop
+
+	case *ast.ExprStmt:
+		// nop
+
+	case *ast.Field:
+		// TODO(adonovan): Field.{Doc,Comment,Tag}?
+
+	case *ast.FieldList:
+		children = append(children,
+			tok(n.Opening, len("(")),
+			tok(n.Closing, len(")")))
+
+	case *ast.File:
+		// TODO test: Doc
+		children = append(children,
+			tok(n.Package, len("package")))
+
+	case *ast.ForStmt:
+		children = append(children,
+			tok(n.For, len("for")))
+
+	case *ast.FuncDecl:
+		// TODO(adonovan): FuncDecl.Comment?
+
+		// Uniquely, FuncDecl breaks the invariant that
+		// preorder traversal yields tokens in lexical order:
+		// in fact, FuncDecl.Recv precedes FuncDecl.Type.Func.
+		//
+		// As a workaround, we inline the case for FuncType
+		// here and order things correctly.
+		//
+		children = nil // discard ast.Walk(FuncDecl) info subtrees
+		children = append(children, tok(n.Type.Func, len("func")))
+		if n.Recv != nil {
+			children = append(children, n.Recv)
+		}
+		children = append(children, n.Name)
+		if n.Type.Params != nil {
+			children = append(children, n.Type.Params)
+		}
+		if n.Type.Results != nil {
+			children = append(children, n.Type.Results)
+		}
+		if n.Body != nil {
+			children = append(children, n.Body)
+		}
+
+	case *ast.FuncLit:
+		// nop
+
+	case *ast.FuncType:
+		if n.Func != 0 {
+			children = append(children,
+				tok(n.Func, len("func")))
+		}
+
+	case *ast.GenDecl:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+		if n.Lparen != 0 {
+			children = append(children,
+				tok(n.Lparen, len("(")),
+				tok(n.Rparen, len(")")))
+		}
+
+	case *ast.GoStmt:
+		children = append(children,
+			tok(n.Go, len("go")))
+
+	case *ast.Ident:
+		children = append(children,
+			tok(n.NamePos, len(n.Name)))
+
+	case *ast.IfStmt:
+		children = append(children,
+			tok(n.If, len("if")))
+
+	case *ast.ImportSpec:
+		// TODO(adonovan): ImportSpec.{Doc,EndPos}?
+
+	case *ast.IncDecStmt:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.IndexExpr:
+		children = append(children,
+			tok(n.Lbrack, len("{")),
+			tok(n.Rbrack, len("}")))
+
+	case *ast.InterfaceType:
+		children = append(children,
+			tok(n.Interface, len("interface")))
+
+	case *ast.KeyValueExpr:
+		children = append(children,
+			tok(n.Colon, len(":")))
+
+	case *ast.LabeledStmt:
+		children = append(children,
+			tok(n.Colon, len(":")))
+
+	case *ast.MapType:
+		children = append(children,
+			tok(n.Map, len("map")))
+
+	case *ast.ParenExpr:
+		children = append(children,
+			tok(n.Lparen, len("(")),
+			tok(n.Rparen, len(")")))
+
+	case *ast.RangeStmt:
+		children = append(children,
+			tok(n.For, len("for")),
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.ReturnStmt:
+		children = append(children,
+			tok(n.Return, len("return")))
+
+	case *ast.SelectStmt:
+		children = append(children,
+			tok(n.Select, len("select")))
+
+	case *ast.SelectorExpr:
+		// nop
+
+	case *ast.SendStmt:
+		children = append(children,
+			tok(n.Arrow, len("<-")))
+
+	case *ast.SliceExpr:
+		children = append(children,
+			tok(n.Lbrack, len("[")),
+			tok(n.Rbrack, len("]")))
+
+	case *ast.StarExpr:
+		children = append(children, tok(n.Star, len("*")))
+
+	case *ast.StructType:
+		children = append(children, tok(n.Struct, len("struct")))
+
+	case *ast.SwitchStmt:
+		children = append(children, tok(n.Switch, len("switch")))
+
+	case *ast.TypeAssertExpr:
+		children = append(children,
+			tok(n.Lparen-1, len(".")),
+			tok(n.Lparen, len("(")),
+			tok(n.Rparen, len(")")))
+
+	case *ast.TypeSpec:
+		// TODO(adonovan): TypeSpec.{Doc,Comment}?
+
+	case *ast.TypeSwitchStmt:
+		children = append(children, tok(n.Switch, len("switch")))
+
+	case *ast.UnaryExpr:
+		children = append(children, tok(n.OpPos, len(n.Op.String())))
+
+	case *ast.ValueSpec:
+		// TODO(adonovan): ValueSpec.{Doc,Comment}?
+
+	case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
+		// nop
+	}
+
+	// TODO(adonovan): opt: merge the logic of ast.Inspect() into
+	// the switch above so we can make interleaved callbacks for
+	// both Nodes and Tokens in the right order and avoid the need
+	// to sort.
+	sort.Sort(byPos(children))
+
+	return children
+}
+
+type byPos []ast.Node
+
+func (sl byPos) Len() int {
+	return len(sl)
+}
+func (sl byPos) Less(i, j int) bool {
+	return sl[i].Pos() < sl[j].Pos()
+}
+func (sl byPos) Swap(i, j int) {
+	sl[i], sl[j] = sl[j], sl[i]
+}
+
+// NodeDescription returns a description of the concrete type of n suitable
+// for a user interface.
+//
+// TODO(adonovan): in some cases (e.g. Field, FieldList, Ident,
+// StarExpr) we could be much more specific given the path to the AST
+// root.  Perhaps we should do that.
+//
+func NodeDescription(n ast.Node) string {
+	switch n := n.(type) {
+	case *ast.ArrayType:
+		return "array type"
+	case *ast.AssignStmt:
+		return "assignment"
+	case *ast.BadDecl:
+		return "bad declaration"
+	case *ast.BadExpr:
+		return "bad expression"
+	case *ast.BadStmt:
+		return "bad statement"
+	case *ast.BasicLit:
+		return "basic literal"
+	case *ast.BinaryExpr:
+		return fmt.Sprintf("binary %s operation", n.Op)
+	case *ast.BlockStmt:
+		return "block"
+	case *ast.BranchStmt:
+		switch n.Tok {
+		case token.BREAK:
+			return "break statement"
+		case token.CONTINUE:
+			return "continue statement"
+		case token.GOTO:
+			return "goto statement"
+		case token.FALLTHROUGH:
+			return "fall-through statement"
+		}
+	case *ast.CallExpr:
+		if len(n.Args) == 1 && !n.Ellipsis.IsValid() {
+			return "function call (or conversion)"
+		}
+		return "function call"
+	case *ast.CaseClause:
+		return "case clause"
+	case *ast.ChanType:
+		return "channel type"
+	case *ast.CommClause:
+		return "communication clause"
+	case *ast.Comment:
+		return "comment"
+	case *ast.CommentGroup:
+		return "comment group"
+	case *ast.CompositeLit:
+		return "composite literal"
+	case *ast.DeclStmt:
+		return NodeDescription(n.Decl) + " statement"
+	case *ast.DeferStmt:
+		return "defer statement"
+	case *ast.Ellipsis:
+		return "ellipsis"
+	case *ast.EmptyStmt:
+		return "empty statement"
+	case *ast.ExprStmt:
+		return "expression statement"
+	case *ast.Field:
+		// Can be any of these:
+		// struct {x, y int}  -- struct field(s)
+		// struct {T}         -- anon struct field
+		// interface {I}      -- interface embedding
+		// interface {f()}    -- interface method
+		// func (A) func(B) C -- receiver, param(s), result(s)
+		return "field/method/parameter"
+	case *ast.FieldList:
+		return "field/method/parameter list"
+	case *ast.File:
+		return "source file"
+	case *ast.ForStmt:
+		return "for loop"
+	case *ast.FuncDecl:
+		return "function declaration"
+	case *ast.FuncLit:
+		return "function literal"
+	case *ast.FuncType:
+		return "function type"
+	case *ast.GenDecl:
+		switch n.Tok {
+		case token.IMPORT:
+			return "import declaration"
+		case token.CONST:
+			return "constant declaration"
+		case token.TYPE:
+			return "type declaration"
+		case token.VAR:
+			return "variable declaration"
+		}
+	case *ast.GoStmt:
+		return "go statement"
+	case *ast.Ident:
+		return "identifier"
+	case *ast.IfStmt:
+		return "if statement"
+	case *ast.ImportSpec:
+		return "import specification"
+	case *ast.IncDecStmt:
+		if n.Tok == token.INC {
+			return "increment statement"
+		}
+		return "decrement statement"
+	case *ast.IndexExpr:
+		return "index expression"
+	case *ast.InterfaceType:
+		return "interface type"
+	case *ast.KeyValueExpr:
+		return "key/value association"
+	case *ast.LabeledStmt:
+		return "statement label"
+	case *ast.MapType:
+		return "map type"
+	case *ast.Package:
+		return "package"
+	case *ast.ParenExpr:
+		return "parenthesized " + NodeDescription(n.X)
+	case *ast.RangeStmt:
+		return "range loop"
+	case *ast.ReturnStmt:
+		return "return statement"
+	case *ast.SelectStmt:
+		return "select statement"
+	case *ast.SelectorExpr:
+		return "selector"
+	case *ast.SendStmt:
+		return "channel send"
+	case *ast.SliceExpr:
+		return "slice expression"
+	case *ast.StarExpr:
+		return "*-operation" // load/store expr or pointer type
+	case *ast.StructType:
+		return "struct type"
+	case *ast.SwitchStmt:
+		return "switch statement"
+	case *ast.TypeAssertExpr:
+		return "type assertion"
+	case *ast.TypeSpec:
+		return "type specification"
+	case *ast.TypeSwitchStmt:
+		return "type switch"
+	case *ast.UnaryExpr:
+		return fmt.Sprintf("unary %s operation", n.Op)
+	case *ast.ValueSpec:
+		return "value specification"
+
+	}
+	panic(fmt.Sprintf("unexpected node type: %T", n))
+}

vendor/golang.org/x/tools/go/ast/astutil/enclosing_test.go

@@ -0,0 +1,195 @@
+// 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.
+
+package astutil_test
+
+// This file defines tests of PathEnclosingInterval.
+
+// TODO(adonovan): exhaustive tests that run over the whole input
+// tree, not just handcrafted examples.
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/ast/astutil"
+)
+
+// pathToString returns a string containing the concrete types of the
+// nodes in path.
+func pathToString(path []ast.Node) string {
+	var buf bytes.Buffer
+	fmt.Fprint(&buf, "[")
+	for i, n := range path {
+		if i > 0 {
+			fmt.Fprint(&buf, " ")
+		}
+		fmt.Fprint(&buf, strings.TrimPrefix(fmt.Sprintf("%T", n), "*ast."))
+	}
+	fmt.Fprint(&buf, "]")
+	return buf.String()
+}
+
+// findInterval parses input and returns the [start, end) positions of
+// the first occurrence of substr in input.  f==nil indicates failure;
+// an error has already been reported in that case.
+//
+func findInterval(t *testing.T, fset *token.FileSet, input, substr string) (f *ast.File, start, end token.Pos) {
+	f, err := parser.ParseFile(fset, "<input>", input, 0)
+	if err != nil {
+		t.Errorf("parse error: %s", err)
+		return
+	}
+
+	i := strings.Index(input, substr)
+	if i < 0 {
+		t.Errorf("%q is not a substring of input", substr)
+		f = nil
+		return
+	}
+
+	filePos := fset.File(f.Package)
+	return f, filePos.Pos(i), filePos.Pos(i + len(substr))
+}
+
+// Common input for following tests.
+const input = `
+// Hello.
+package main
+import "fmt"
+func f() {}
+func main() {
+	z := (x + y) // add them
+        f() // NB: ExprStmt and its CallExpr have same Pos/End
+}
+`
+
+func TestPathEnclosingInterval_Exact(t *testing.T) {
+	// For the exact tests, we check that a substring is mapped to
+	// the canonical string for the node it denotes.
+	tests := []struct {
+		substr string // first occurrence of this string indicates interval
+		node   string // complete text of expected containing node
+	}{
+		{"package",
+			input[11 : len(input)-1]},
+		{"\npack",
+			input[11 : len(input)-1]},
+		{"main",
+			"main"},
+		{"import",
+			"import \"fmt\""},
+		{"\"fmt\"",
+			"\"fmt\""},
+		{"\nfunc f() {}\n",
+			"func f() {}"},
+		{"x ",
+			"x"},
+		{" y",
+			"y"},
+		{"z",
+			"z"},
+		{" + ",
+			"x + y"},
+		{" :=",
+			"z := (x + y)"},
+		{"x + y",
+			"x + y"},
+		{"(x + y)",
+			"(x + y)"},
+		{" (x + y) ",
+			"(x + y)"},
+		{" (x + y) // add",
+			"(x + y)"},
+		{"func",
+			"func f() {}"},
+		{"func f() {}",
+			"func f() {}"},
+		{"\nfun",
+			"func f() {}"},
+		{" f",
+			"f"},
+	}
+	for _, test := range tests {
+		f, start, end := findInterval(t, new(token.FileSet), input, test.substr)
+		if f == nil {
+			continue
+		}
+
+		path, exact := astutil.PathEnclosingInterval(f, start, end)
+		if !exact {
+			t.Errorf("PathEnclosingInterval(%q) not exact", test.substr)
+			continue
+		}
+
+		if len(path) == 0 {
+			if test.node != "" {
+				t.Errorf("PathEnclosingInterval(%q).path: got [], want %q",
+					test.substr, test.node)
+			}
+			continue
+		}
+
+		if got := input[path[0].Pos():path[0].End()]; got != test.node {
+			t.Errorf("PathEnclosingInterval(%q): got %q, want %q (path was %s)",
+				test.substr, got, test.node, pathToString(path))
+			continue
+		}
+	}
+}
+
+func TestPathEnclosingInterval_Paths(t *testing.T) {
+	// For these tests, we check only the path of the enclosing
+	// node, but not its complete text because it's often quite
+	// large when !exact.
+	tests := []struct {
+		substr string // first occurrence of this string indicates interval
+		path   string // the pathToString(),exact of the expected path
+	}{
+		{"// add",
+			"[BlockStmt FuncDecl File],false"},
+		{"(x + y",
+			"[ParenExpr AssignStmt BlockStmt FuncDecl File],false"},
+		{"x +",
+			"[BinaryExpr ParenExpr AssignStmt BlockStmt FuncDecl File],false"},
+		{"z := (x",
+			"[AssignStmt BlockStmt FuncDecl File],false"},
+		{"func f",
+			"[FuncDecl File],false"},
+		{"func f()",
+			"[FuncDecl File],false"},
+		{" f()",
+			"[FuncDecl File],false"},
+		{"() {}",
+			"[FuncDecl File],false"},
+		{"// Hello",
+			"[File],false"},
+		{" f",
+			"[Ident FuncDecl File],true"},
+		{"func ",
+			"[FuncDecl File],true"},
+		{"mai",
+			"[Ident File],true"},
+		{"f() // NB",
+			"[CallExpr ExprStmt BlockStmt FuncDecl File],true"},
+	}
+	for _, test := range tests {
+		f, start, end := findInterval(t, new(token.FileSet), input, test.substr)
+		if f == nil {
+			continue
+		}
+
+		path, exact := astutil.PathEnclosingInterval(f, start, end)
+		if got := fmt.Sprintf("%s,%v", pathToString(path), exact); got != test.path {
+			t.Errorf("PathEnclosingInterval(%q): got %q, want %q",
+				test.substr, got, test.path)
+			continue
+		}
+	}
+}

vendor/golang.org/x/tools/go/ast/astutil/imports.go

@@ -0,0 +1,471 @@
+// 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.
+
+// Package astutil contains common utilities for working with the Go AST.
+package astutil // import "golang.org/x/tools/go/ast/astutil"
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strconv"
+	"strings"
+)
+
+// AddImport adds the import path to the file f, if absent.
+func AddImport(fset *token.FileSet, f *ast.File, ipath string) (added bool) {
+	return AddNamedImport(fset, f, "", ipath)
+}
+
+// AddNamedImport adds the import path to the file f, if absent.
+// If name is not empty, it is used to rename the import.
+//
+// For example, calling
+//	AddNamedImport(fset, f, "pathpkg", "path")
+// adds
+//	import pathpkg "path"
+func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool) {
+	if imports(f, ipath) {
+		return false
+	}
+
+	newImport := &ast.ImportSpec{
+		Path: &ast.BasicLit{
+			Kind:  token.STRING,
+			Value: strconv.Quote(ipath),
+		},
+	}
+	if name != "" {
+		newImport.Name = &ast.Ident{Name: name}
+	}
+
+	// Find an import decl to add to.
+	// The goal is to find an existing import
+	// whose import path has the longest shared
+	// prefix with ipath.
+	var (
+		bestMatch  = -1         // length of longest shared prefix
+		lastImport = -1         // index in f.Decls of the file's final import decl
+		impDecl    *ast.GenDecl // import decl containing the best match
+		impIndex   = -1         // spec index in impDecl containing the best match
+
+		isThirdPartyPath = isThirdParty(ipath)
+	)
+	for i, decl := range f.Decls {
+		gen, ok := decl.(*ast.GenDecl)
+		if ok && gen.Tok == token.IMPORT {
+			lastImport = i
+			// Do not add to import "C", to avoid disrupting the
+			// association with its doc comment, breaking cgo.
+			if declImports(gen, "C") {
+				continue
+			}
+
+			// Match an empty import decl if that's all that is available.
+			if len(gen.Specs) == 0 && bestMatch == -1 {
+				impDecl = gen
+			}
+
+			// Compute longest shared prefix with imports in this group and find best
+			// matched import spec.
+			// 1. Always prefer import spec with longest shared prefix.
+			// 2. While match length is 0,
+			// - for stdlib package: prefer first import spec.
+			// - for third party package: prefer first third party import spec.
+			// We cannot use last import spec as best match for third party package
+			// because grouped imports are usually placed last by goimports -local
+			// flag.
+			// See issue #19190.
+			seenAnyThirdParty := false
+			for j, spec := range gen.Specs {
+				impspec := spec.(*ast.ImportSpec)
+				p := importPath(impspec)
+				n := matchLen(p, ipath)
+				if n > bestMatch || (bestMatch == 0 && !seenAnyThirdParty && isThirdPartyPath) {
+					bestMatch = n
+					impDecl = gen
+					impIndex = j
+				}
+				seenAnyThirdParty = seenAnyThirdParty || isThirdParty(p)
+			}
+		}
+	}
+
+	// If no import decl found, add one after the last import.
+	if impDecl == nil {
+		impDecl = &ast.GenDecl{
+			Tok: token.IMPORT,
+		}
+		if lastImport >= 0 {
+			impDecl.TokPos = f.Decls[lastImport].End()
+		} else {
+			// There are no existing imports.
+			// Our new import, preceded by a blank line,  goes after the package declaration
+			// and after the comment, if any, that starts on the same line as the
+			// package declaration.
+			impDecl.TokPos = f.Package
+
+			file := fset.File(f.Package)
+			pkgLine := file.Line(f.Package)
+			for _, c := range f.Comments {
+				if file.Line(c.Pos()) > pkgLine {
+					break
+				}
+				// +2 for a blank line
+				impDecl.TokPos = c.End() + 2
+			}
+		}
+		f.Decls = append(f.Decls, nil)
+		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
+		f.Decls[lastImport+1] = impDecl
+	}
+
+	// Insert new import at insertAt.
+	insertAt := 0
+	if impIndex >= 0 {
+		// insert after the found import
+		insertAt = impIndex + 1
+	}
+	impDecl.Specs = append(impDecl.Specs, nil)
+	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
+	impDecl.Specs[insertAt] = newImport
+	pos := impDecl.Pos()
+	if insertAt > 0 {
+		// If there is a comment after an existing import, preserve the comment
+		// position by adding the new import after the comment.
+		if spec, ok := impDecl.Specs[insertAt-1].(*ast.ImportSpec); ok && spec.Comment != nil {
+			pos = spec.Comment.End()
+		} else {
+			// Assign same position as the previous import,
+			// so that the sorter sees it as being in the same block.
+			pos = impDecl.Specs[insertAt-1].Pos()
+		}
+	}
+	if newImport.Name != nil {
+		newImport.Name.NamePos = pos
+	}
+	newImport.Path.ValuePos = pos
+	newImport.EndPos = pos
+
+	// Clean up parens. impDecl contains at least one spec.
+	if len(impDecl.Specs) == 1 {
+		// Remove unneeded parens.
+		impDecl.Lparen = token.NoPos
+	} else if !impDecl.Lparen.IsValid() {
+		// impDecl needs parens added.
+		impDecl.Lparen = impDecl.Specs[0].Pos()
+	}
+
+	f.Imports = append(f.Imports, newImport)
+
+	if len(f.Decls) <= 1 {
+		return true
+	}
+
+	// Merge all the import declarations into the first one.
+	var first *ast.GenDecl
+	for i := 0; i < len(f.Decls); i++ {
+		decl := f.Decls[i]
+		gen, ok := decl.(*ast.GenDecl)
+		if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
+			continue
+		}
+		if first == nil {
+			first = gen
+			continue // Don't touch the first one.
+		}
+		// We now know there is more than one package in this import
+		// declaration. Ensure that it ends up parenthesized.
+		first.Lparen = first.Pos()
+		// Move the imports of the other import declaration to the first one.
+		for _, spec := range gen.Specs {
+			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
+			first.Specs = append(first.Specs, spec)
+		}
+		f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
+		i--
+	}
+
+	return true
+}
+
+func isThirdParty(importPath string) bool {
+	// Third party package import path usually contains "." (".com", ".org", ...)
+	// This logic is taken from golang.org/x/tools/imports package.
+	return strings.Contains(importPath, ".")
+}
+
+// DeleteImport deletes the import path from the file f, if present.
+func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool) {
+	return DeleteNamedImport(fset, f, "", path)
+}
+
+// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
+func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
+	var delspecs []*ast.ImportSpec
+	var delcomments []*ast.CommentGroup
+
+	// Find the import nodes that import path, if any.
+	for i := 0; i < len(f.Decls); i++ {
+		decl := f.Decls[i]
+		gen, ok := decl.(*ast.GenDecl)
+		if !ok || gen.Tok != token.IMPORT {
+			continue
+		}
+		for j := 0; j < len(gen.Specs); j++ {
+			spec := gen.Specs[j]
+			impspec := spec.(*ast.ImportSpec)
+			if impspec.Name == nil && name != "" {
+				continue
+			}
+			if impspec.Name != nil && impspec.Name.Name != name {
+				continue
+			}
+			if importPath(impspec) != path {
+				continue
+			}
+
+			// We found an import spec that imports path.
+			// Delete it.
+			delspecs = append(delspecs, impspec)
+			deleted = true
+			copy(gen.Specs[j:], gen.Specs[j+1:])
+			gen.Specs = gen.Specs[:len(gen.Specs)-1]
+
+			// If this was the last import spec in this decl,
+			// delete the decl, too.
+			if len(gen.Specs) == 0 {
+				copy(f.Decls[i:], f.Decls[i+1:])
+				f.Decls = f.Decls[:len(f.Decls)-1]
+				i--
+				break
+			} else if len(gen.Specs) == 1 {
+				if impspec.Doc != nil {
+					delcomments = append(delcomments, impspec.Doc)
+				}
+				if impspec.Comment != nil {
+					delcomments = append(delcomments, impspec.Comment)
+				}
+				for _, cg := range f.Comments {
+					// Found comment on the same line as the import spec.
+					if cg.End() < impspec.Pos() && fset.Position(cg.End()).Line == fset.Position(impspec.Pos()).Line {
+						delcomments = append(delcomments, cg)
+						break
+					}
+				}
+
+				spec := gen.Specs[0].(*ast.ImportSpec)
+
+				// Move the documentation right after the import decl.
+				if spec.Doc != nil {
+					for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Doc.Pos()).Line {
+						fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
+					}
+				}
+				for _, cg := range f.Comments {
+					if cg.End() < spec.Pos() && fset.Position(cg.End()).Line == fset.Position(spec.Pos()).Line {
+						for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Pos()).Line {
+							fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
+						}
+						break
+					}
+				}
+			}
+			if j > 0 {
+				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
+				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
+				line := fset.Position(impspec.Path.ValuePos).Line
+
+				// We deleted an entry but now there may be
+				// a blank line-sized hole where the import was.
+				if line-lastLine > 1 {
+					// There was a blank line immediately preceding the deleted import,
+					// so there's no need to close the hole.
+					// Do nothing.
+				} else if line != fset.File(gen.Rparen).LineCount() {
+					// There was no blank line. Close the hole.
+					fset.File(gen.Rparen).MergeLine(line)
+				}
+			}
+			j--
+		}
+	}
+
+	// Delete imports from f.Imports.
+	for i := 0; i < len(f.Imports); i++ {
+		imp := f.Imports[i]
+		for j, del := range delspecs {
+			if imp == del {
+				copy(f.Imports[i:], f.Imports[i+1:])
+				f.Imports = f.Imports[:len(f.Imports)-1]
+				copy(delspecs[j:], delspecs[j+1:])
+				delspecs = delspecs[:len(delspecs)-1]
+				i--
+				break
+			}
+		}
+	}
+
+	// Delete comments from f.Comments.
+	for i := 0; i < len(f.Comments); i++ {
+		cg := f.Comments[i]
+		for j, del := range delcomments {
+			if cg == del {
+				copy(f.Comments[i:], f.Comments[i+1:])
+				f.Comments = f.Comments[:len(f.Comments)-1]
+				copy(delcomments[j:], delcomments[j+1:])
+				delcomments = delcomments[:len(delcomments)-1]
+				i--
+				break
+			}
+		}
+	}
+
+	if len(delspecs) > 0 {
+		panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
+	}
+
+	return
+}
+
+// RewriteImport rewrites any import of path oldPath to path newPath.
+func RewriteImport(fset *token.FileSet, f *ast.File, oldPath, newPath string) (rewrote bool) {
+	for _, imp := range f.Imports {
+		if importPath(imp) == oldPath {
+			rewrote = true
+			// record old End, because the default is to compute
+			// it using the length of imp.Path.Value.
+			imp.EndPos = imp.End()
+			imp.Path.Value = strconv.Quote(newPath)
+		}
+	}
+	return
+}
+
+// UsesImport reports whether a given import is used.
+func UsesImport(f *ast.File, path string) (used bool) {
+	spec := importSpec(f, path)
+	if spec == nil {
+		return
+	}
+
+	name := spec.Name.String()
+	switch name {
+	case "<nil>":
+		// If the package name is not explicitly specified,
+		// make an educated guess. This is not guaranteed to be correct.
+		lastSlash := strings.LastIndex(path, "/")
+		if lastSlash == -1 {
+			name = path
+		} else {
+			name = path[lastSlash+1:]
+		}
+	case "_", ".":
+		// Not sure if this import is used - err on the side of caution.
+		return true
+	}
+
+	ast.Walk(visitFn(func(n ast.Node) {
+		sel, ok := n.(*ast.SelectorExpr)
+		if ok && isTopName(sel.X, name) {
+			used = true
+		}
+	}), f)
+
+	return
+}
+
+type visitFn func(node ast.Node)
+
+func (fn visitFn) Visit(node ast.Node) ast.Visitor {
+	fn(node)
+	return fn
+}
+
+// imports returns true if f imports path.
+func imports(f *ast.File, path string) bool {
+	return importSpec(f, path) != nil
+}
+
+// importSpec returns the import spec if f imports path,
+// or nil otherwise.
+func importSpec(f *ast.File, path string) *ast.ImportSpec {
+	for _, s := range f.Imports {
+		if importPath(s) == path {
+			return s
+		}
+	}
+	return nil
+}
+
+// importPath returns the unquoted import path of s,
+// or "" if the path is not properly quoted.
+func importPath(s *ast.ImportSpec) string {
+	t, err := strconv.Unquote(s.Path.Value)
+	if err == nil {
+		return t
+	}
+	return ""
+}
+
+// declImports reports whether gen contains an import of path.
+func declImports(gen *ast.GenDecl, path string) bool {
+	if gen.Tok != token.IMPORT {
+		return false
+	}
+	for _, spec := range gen.Specs {
+		impspec := spec.(*ast.ImportSpec)
+		if importPath(impspec) == path {
+			return true
+		}
+	}
+	return false
+}
+
+// matchLen returns the length of the longest path segment prefix shared by x and y.
+func matchLen(x, y string) int {
+	n := 0
+	for i := 0; i < len(x) && i < len(y) && x[i] == y[i]; i++ {
+		if x[i] == '/' {
+			n++
+		}
+	}
+	return n
+}
+
+// isTopName returns true if n is a top-level unresolved identifier with the given name.
+func isTopName(n ast.Expr, name string) bool {
+	id, ok := n.(*ast.Ident)
+	return ok && id.Name == name && id.Obj == nil
+}
+
+// Imports returns the file imports grouped by paragraph.
+func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec {
+	var groups [][]*ast.ImportSpec
+
+	for _, decl := range f.Decls {
+		genDecl, ok := decl.(*ast.GenDecl)
+		if !ok || genDecl.Tok != token.IMPORT {
+			break
+		}
+
+		group := []*ast.ImportSpec{}
+
+		var lastLine int
+		for _, spec := range genDecl.Specs {
+			importSpec := spec.(*ast.ImportSpec)
+			pos := importSpec.Path.ValuePos
+			line := fset.Position(pos).Line
+			if lastLine > 0 && pos > 0 && line-lastLine > 1 {
+				groups = append(groups, group)
+				group = []*ast.ImportSpec{}
+			}
+			group = append(group, importSpec)
+			lastLine = line
+		}
+		groups = append(groups, group)
+	}
+
+	return groups
+}

vendor/golang.org/x/tools/go/ast/astutil/rewrite.go

@@ -0,0 +1,477 @@
+// Copyright 2017 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 astutil
+
+import (
+	"fmt"
+	"go/ast"
+	"reflect"
+	"sort"
+)
+
+// An ApplyFunc is invoked by Apply for each node n, even if n is nil,
+// before and/or after the node's children, using a Cursor describing
+// the current node and providing operations on it.
+//
+// The return value of ApplyFunc controls the syntax tree traversal.
+// See Apply for details.
+type ApplyFunc func(*Cursor) bool
+
+// Apply traverses a syntax tree recursively, starting with root,
+// and calling pre and post for each node as described below.
+// Apply returns the syntax tree, possibly modified.
+//
+// If pre is not nil, it is called for each node before the node's
+// children are traversed (pre-order). If pre returns false, no
+// children are traversed, and post is not called for that node.
+//
+// If post is not nil, and a prior call of pre didn't return false,
+// post is called for each node after its children are traversed
+// (post-order). If post returns false, traversal is terminated and
+// Apply returns immediately.
+//
+// Only fields that refer to AST nodes are considered children;
+// i.e., token.Pos, Scopes, Objects, and fields of basic types
+// (strings, etc.) are ignored.
+//
+// Children are traversed in the order in which they appear in the
+// respective node's struct definition. A package's files are
+// traversed in the filenames' alphabetical order.
+//
+func Apply(root ast.Node, pre, post ApplyFunc) (result ast.Node) {
+	parent := &struct{ ast.Node }{root}
+	defer func() {
+		if r := recover(); r != nil && r != abort {
+			panic(r)
+		}
+		result = parent.Node
+	}()
+	a := &application{pre: pre, post: post}
+	a.apply(parent, "Node", nil, root)
+	return
+}
+
+var abort = new(int) // singleton, to signal termination of Apply
+
+// A Cursor describes a node encountered during Apply.
+// Information about the node and its parent is available
+// from the Node, Parent, Name, and Index methods.
+//
+// If p is a variable of type and value of the current parent node
+// c.Parent(), and f is the field identifier with name c.Name(),
+// the following invariants hold:
+//
+//   p.f            == c.Node()  if c.Index() <  0
+//   p.f[c.Index()] == c.Node()  if c.Index() >= 0
+//
+// The methods Replace, Delete, InsertBefore, and InsertAfter
+// can be used to change the AST without disrupting Apply.
+type Cursor struct {
+	parent ast.Node
+	name   string
+	iter   *iterator // valid if non-nil
+	node   ast.Node
+}
+
+// Node returns the current Node.
+func (c *Cursor) Node() ast.Node { return c.node }
+
+// Parent returns the parent of the current Node.
+func (c *Cursor) Parent() ast.Node { return c.parent }
+
+// Name returns the name of the parent Node field that contains the current Node.
+// If the parent is a *ast.Package and the current Node is a *ast.File, Name returns
+// the filename for the current Node.
+func (c *Cursor) Name() string { return c.name }
+
+// Index reports the index >= 0 of the current Node in the slice of Nodes that
+// contains it, or a value < 0 if the current Node is not part of a slice.
+// The index of the current node changes if InsertBefore is called while
+// processing the current node.
+func (c *Cursor) Index() int {
+	if c.iter != nil {
+		return c.iter.index
+	}
+	return -1
+}
+
+// field returns the current node's parent field value.
+func (c *Cursor) field() reflect.Value {
+	return reflect.Indirect(reflect.ValueOf(c.parent)).FieldByName(c.name)
+}
+
+// Replace replaces the current Node with n.
+// The replacement node is not walked by Apply.
+func (c *Cursor) Replace(n ast.Node) {
+	if _, ok := c.node.(*ast.File); ok {
+		file, ok := n.(*ast.File)
+		if !ok {
+			panic("attempt to replace *ast.File with non-*ast.File")
+		}
+		c.parent.(*ast.Package).Files[c.name] = file
+		return
+	}
+
+	v := c.field()
+	if i := c.Index(); i >= 0 {
+		v = v.Index(i)
+	}
+	v.Set(reflect.ValueOf(n))
+}
+
+// Delete deletes the current Node from its containing slice.
+// If the current Node is not part of a slice, Delete panics.
+// As a special case, if the current node is a package file,
+// Delete removes it from the package's Files map.
+func (c *Cursor) Delete() {
+	if _, ok := c.node.(*ast.File); ok {
+		delete(c.parent.(*ast.Package).Files, c.name)
+		return
+	}
+
+	i := c.Index()
+	if i < 0 {
+		panic("Delete node not contained in slice")
+	}
+	v := c.field()
+	l := v.Len()
+	reflect.Copy(v.Slice(i, l), v.Slice(i+1, l))
+	v.Index(l - 1).Set(reflect.Zero(v.Type().Elem()))
+	v.SetLen(l - 1)
+	c.iter.step--
+}
+
+// InsertAfter inserts n after the current Node in its containing slice.
+// If the current Node is not part of a slice, InsertAfter panics.
+// Apply does not walk n.
+func (c *Cursor) InsertAfter(n ast.Node) {
+	i := c.Index()
+	if i < 0 {
+		panic("InsertAfter node not contained in slice")
+	}
+	v := c.field()
+	v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
+	l := v.Len()
+	reflect.Copy(v.Slice(i+2, l), v.Slice(i+1, l))
+	v.Index(i + 1).Set(reflect.ValueOf(n))
+	c.iter.step++
+}
+
+// InsertBefore inserts n before the current Node in its containing slice.
+// If the current Node is not part of a slice, InsertBefore panics.
+// Apply will not walk n.
+func (c *Cursor) InsertBefore(n ast.Node) {
+	i := c.Index()
+	if i < 0 {
+		panic("InsertBefore node not contained in slice")
+	}
+	v := c.field()
+	v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
+	l := v.Len()
+	reflect.Copy(v.Slice(i+1, l), v.Slice(i, l))
+	v.Index(i).Set(reflect.ValueOf(n))
+	c.iter.index++
+}
+
+// application carries all the shared data so we can pass it around cheaply.
+type application struct {
+	pre, post ApplyFunc
+	cursor    Cursor
+	iter      iterator
+}
+
+func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.Node) {
+	// convert typed nil into untyped nil
+	if v := reflect.ValueOf(n); v.Kind() == reflect.Ptr && v.IsNil() {
+		n = nil
+	}
+
+	// avoid heap-allocating a new cursor for each apply call; reuse a.cursor instead
+	saved := a.cursor
+	a.cursor.parent = parent
+	a.cursor.name = name
+	a.cursor.iter = iter
+	a.cursor.node = n
+
+	if a.pre != nil && !a.pre(&a.cursor) {
+		a.cursor = saved
+		return
+	}
+
+	// walk children
+	// (the order of the cases matches the order of the corresponding node types in go/ast)
+	switch n := n.(type) {
+	case nil:
+		// nothing to do
+
+	// Comments and fields
+	case *ast.Comment:
+		// nothing to do
+
+	case *ast.CommentGroup:
+		if n != nil {
+			a.applyList(n, "List")
+		}
+
+	case *ast.Field:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.applyList(n, "Names")
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Tag", nil, n.Tag)
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.FieldList:
+		a.applyList(n, "List")
+
+	// Expressions
+	case *ast.BadExpr, *ast.Ident, *ast.BasicLit:
+		// nothing to do
+
+	case *ast.Ellipsis:
+		a.apply(n, "Elt", nil, n.Elt)
+
+	case *ast.FuncLit:
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.CompositeLit:
+		a.apply(n, "Type", nil, n.Type)
+		a.applyList(n, "Elts")
+
+	case *ast.ParenExpr:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.SelectorExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Sel", nil, n.Sel)
+
+	case *ast.IndexExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Index", nil, n.Index)
+
+	case *ast.SliceExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Low", nil, n.Low)
+		a.apply(n, "High", nil, n.High)
+		a.apply(n, "Max", nil, n.Max)
+
+	case *ast.TypeAssertExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Type", nil, n.Type)
+
+	case *ast.CallExpr:
+		a.apply(n, "Fun", nil, n.Fun)
+		a.applyList(n, "Args")
+
+	case *ast.StarExpr:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.UnaryExpr:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.BinaryExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Y", nil, n.Y)
+
+	case *ast.KeyValueExpr:
+		a.apply(n, "Key", nil, n.Key)
+		a.apply(n, "Value", nil, n.Value)
+
+	// Types
+	case *ast.ArrayType:
+		a.apply(n, "Len", nil, n.Len)
+		a.apply(n, "Elt", nil, n.Elt)
+
+	case *ast.StructType:
+		a.apply(n, "Fields", nil, n.Fields)
+
+	case *ast.FuncType:
+		a.apply(n, "Params", nil, n.Params)
+		a.apply(n, "Results", nil, n.Results)
+
+	case *ast.InterfaceType:
+		a.apply(n, "Methods", nil, n.Methods)
+
+	case *ast.MapType:
+		a.apply(n, "Key", nil, n.Key)
+		a.apply(n, "Value", nil, n.Value)
+
+	case *ast.ChanType:
+		a.apply(n, "Value", nil, n.Value)
+
+	// Statements
+	case *ast.BadStmt:
+		// nothing to do
+
+	case *ast.DeclStmt:
+		a.apply(n, "Decl", nil, n.Decl)
+
+	case *ast.EmptyStmt:
+		// nothing to do
+
+	case *ast.LabeledStmt:
+		a.apply(n, "Label", nil, n.Label)
+		a.apply(n, "Stmt", nil, n.Stmt)
+
+	case *ast.ExprStmt:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.SendStmt:
+		a.apply(n, "Chan", nil, n.Chan)
+		a.apply(n, "Value", nil, n.Value)
+
+	case *ast.IncDecStmt:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.AssignStmt:
+		a.applyList(n, "Lhs")
+		a.applyList(n, "Rhs")
+
+	case *ast.GoStmt:
+		a.apply(n, "Call", nil, n.Call)
+
+	case *ast.DeferStmt:
+		a.apply(n, "Call", nil, n.Call)
+
+	case *ast.ReturnStmt:
+		a.applyList(n, "Results")
+
+	case *ast.BranchStmt:
+		a.apply(n, "Label", nil, n.Label)
+
+	case *ast.BlockStmt:
+		a.applyList(n, "List")
+
+	case *ast.IfStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Cond", nil, n.Cond)
+		a.apply(n, "Body", nil, n.Body)
+		a.apply(n, "Else", nil, n.Else)
+
+	case *ast.CaseClause:
+		a.applyList(n, "List")
+		a.applyList(n, "Body")
+
+	case *ast.SwitchStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Tag", nil, n.Tag)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.TypeSwitchStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Assign", nil, n.Assign)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.CommClause:
+		a.apply(n, "Comm", nil, n.Comm)
+		a.applyList(n, "Body")
+
+	case *ast.SelectStmt:
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.ForStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Cond", nil, n.Cond)
+		a.apply(n, "Post", nil, n.Post)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.RangeStmt:
+		a.apply(n, "Key", nil, n.Key)
+		a.apply(n, "Value", nil, n.Value)
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Body", nil, n.Body)
+
+	// Declarations
+	case *ast.ImportSpec:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Name", nil, n.Name)
+		a.apply(n, "Path", nil, n.Path)
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.ValueSpec:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.applyList(n, "Names")
+		a.apply(n, "Type", nil, n.Type)
+		a.applyList(n, "Values")
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.TypeSpec:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Name", nil, n.Name)
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.BadDecl:
+		// nothing to do
+
+	case *ast.GenDecl:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.applyList(n, "Specs")
+
+	case *ast.FuncDecl:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Recv", nil, n.Recv)
+		a.apply(n, "Name", nil, n.Name)
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Body", nil, n.Body)
+
+	// Files and packages
+	case *ast.File:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Name", nil, n.Name)
+		a.applyList(n, "Decls")
+		// Don't walk n.Comments; they have either been walked already if
+		// they are Doc comments, or they can be easily walked explicitly.
+
+	case *ast.Package:
+		// collect and sort names for reproducible behavior
+		var names []string
+		for name := range n.Files {
+			names = append(names, name)
+		}
+		sort.Strings(names)
+		for _, name := range names {
+			a.apply(n, name, nil, n.Files[name])
+		}
+
+	default:
+		panic(fmt.Sprintf("Apply: unexpected node type %T", n))
+	}
+
+	if a.post != nil && !a.post(&a.cursor) {
+		panic(abort)
+	}
+
+	a.cursor = saved
+}
+
+// An iterator controls iteration over a slice of nodes.
+type iterator struct {
+	index, step int
+}
+
+func (a *application) applyList(parent ast.Node, name string) {
+	// avoid heap-allocating a new iterator for each applyList call; reuse a.iter instead
+	saved := a.iter
+	a.iter.index = 0
+	for {
+		// must reload parent.name each time, since cursor modifications might change it
+		v := reflect.Indirect(reflect.ValueOf(parent)).FieldByName(name)
+		if a.iter.index >= v.Len() {
+			break
+		}
+
+		// element x may be nil in a bad AST - be cautious
+		var x ast.Node
+		if e := v.Index(a.iter.index); e.IsValid() {
+			x = e.Interface().(ast.Node)
+		}
+
+		a.iter.step = 1
+		a.apply(parent, name, &a.iter, x)
+		a.iter.index += a.iter.step
+	}
+	a.iter = saved
+}

vendor/golang.org/x/tools/go/ast/astutil/rewrite_test.go

@@ -0,0 +1,248 @@
+// Copyright 2017 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 astutil_test
+
+import (
+	"bytes"
+	"go/ast"
+	"go/format"
+	"go/parser"
+	"go/token"
+	"testing"
+
+	"golang.org/x/tools/go/ast/astutil"
+)
+
+var rewriteTests = [...]struct {
+	name       string
+	orig, want string
+	pre, post  astutil.ApplyFunc
+}{
+	{name: "nop", orig: "package p\n", want: "package p\n"},
+
+	{name: "replace",
+		orig: `package p
+
+var x int
+`,
+		want: `package p
+
+var t T
+`,
+		post: func(c *astutil.Cursor) bool {
+			if _, ok := c.Node().(*ast.ValueSpec); ok {
+				c.Replace(valspec("t", "T"))
+				return false
+			}
+			return true
+		},
+	},
+
+	{name: "set doc strings",
+		orig: `package p
+
+const z = 0
+
+type T struct{}
+
+var x int
+`,
+		want: `package p
+// a foo is a foo
+const z = 0
+// a foo is a foo
+type T struct{}
+// a foo is a foo
+var x int
+`,
+		post: func(c *astutil.Cursor) bool {
+			if _, ok := c.Parent().(*ast.GenDecl); ok && c.Name() == "Doc" && c.Node() == nil {
+				c.Replace(&ast.CommentGroup{List: []*ast.Comment{{Text: "// a foo is a foo"}}})
+			}
+			return true
+		},
+	},
+
+	{name: "insert names",
+		orig: `package p
+
+const a = 1
+`,
+		want: `package p
+
+const a, b, c = 1, 2, 3
+`,
+		pre: func(c *astutil.Cursor) bool {
+			if _, ok := c.Parent().(*ast.ValueSpec); ok {
+				switch c.Name() {
+				case "Names":
+					c.InsertAfter(ast.NewIdent("c"))
+					c.InsertAfter(ast.NewIdent("b"))
+				case "Values":
+					c.InsertAfter(&ast.BasicLit{Kind: token.INT, Value: "3"})
+					c.InsertAfter(&ast.BasicLit{Kind: token.INT, Value: "2"})
+				}
+			}
+			return true
+		},
+	},
+
+	{name: "insert",
+		orig: `package p
+
+var (
+	x int
+	y int
+)
+`,
+		want: `package p
+
+var before1 int
+var before2 int
+
+var (
+	x int
+	y int
+)
+var after2 int
+var after1 int
+`,
+		pre: func(c *astutil.Cursor) bool {
+			if _, ok := c.Node().(*ast.GenDecl); ok {
+				c.InsertBefore(vardecl("before1", "int"))
+				c.InsertAfter(vardecl("after1", "int"))
+				c.InsertAfter(vardecl("after2", "int"))
+				c.InsertBefore(vardecl("before2", "int"))
+			}
+			return true
+		},
+	},
+
+	{name: "delete",
+		orig: `package p
+
+var x int
+var y int
+var z int
+`,
+		want: `package p
+
+var y int
+var z int
+`,
+		pre: func(c *astutil.Cursor) bool {
+			n := c.Node()
+			if d, ok := n.(*ast.GenDecl); ok && d.Specs[0].(*ast.ValueSpec).Names[0].Name == "x" {
+				c.Delete()
+			}
+			return true
+		},
+	},
+
+	{name: "insertafter-delete",
+		orig: `package p
+
+var x int
+var y int
+var z int
+`,
+		want: `package p
+
+var x1 int
+
+var y int
+var z int
+`,
+		pre: func(c *astutil.Cursor) bool {
+			n := c.Node()
+			if d, ok := n.(*ast.GenDecl); ok && d.Specs[0].(*ast.ValueSpec).Names[0].Name == "x" {
+				c.InsertAfter(vardecl("x1", "int"))
+				c.Delete()
+			}
+			return true
+		},
+	},
+
+	{name: "delete-insertafter",
+		orig: `package p
+
+var x int
+var y int
+var z int
+`,
+		want: `package p
+
+var y int
+var x1 int
+var z int
+`,
+		pre: func(c *astutil.Cursor) bool {
+			n := c.Node()
+			if d, ok := n.(*ast.GenDecl); ok && d.Specs[0].(*ast.ValueSpec).Names[0].Name == "x" {
+				c.Delete()
+				// The cursor is now effectively atop the 'var y int' node.
+				c.InsertAfter(vardecl("x1", "int"))
+			}
+			return true
+		},
+	},
+}
+
+func valspec(name, typ string) *ast.ValueSpec {
+	return &ast.ValueSpec{Names: []*ast.Ident{ast.NewIdent(name)},
+		Type: ast.NewIdent(typ),
+	}
+}
+
+func vardecl(name, typ string) *ast.GenDecl {
+	return &ast.GenDecl{
+		Tok:   token.VAR,
+		Specs: []ast.Spec{valspec(name, typ)},
+	}
+}
+
+func TestRewrite(t *testing.T) {
+	t.Run("*", func(t *testing.T) {
+		for _, test := range rewriteTests {
+			test := test
+			t.Run(test.name, func(t *testing.T) {
+				t.Parallel()
+				fset := token.NewFileSet()
+				f, err := parser.ParseFile(fset, test.name, test.orig, parser.ParseComments)
+				if err != nil {
+					t.Fatal(err)
+				}
+				n := astutil.Apply(f, test.pre, test.post)
+				var buf bytes.Buffer
+				if err := format.Node(&buf, fset, n); err != nil {
+					t.Fatal(err)
+				}
+				got := buf.String()
+				if got != test.want {
+					t.Errorf("got:\n\n%s\nwant:\n\n%s\n", got, test.want)
+				}
+			})
+		}
+	})
+}
+
+var sink ast.Node
+
+func BenchmarkRewrite(b *testing.B) {
+	for _, test := range rewriteTests {
+		b.Run(test.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				b.StopTimer()
+				fset := token.NewFileSet()
+				f, err := parser.ParseFile(fset, test.name, test.orig, parser.ParseComments)
+				if err != nil {
+					b.Fatal(err)
+				}
+				b.StartTimer()
+				sink = astutil.Apply(f, test.pre, test.post)
+			}
+		})
+	}
+}

vendor/golang.org/x/tools/go/ast/astutil/util.go

@@ -0,0 +1,14 @@
+package astutil
+
+import "go/ast"
+
+// Unparen returns e with any enclosing parentheses stripped.
+func Unparen(e ast.Expr) ast.Expr {
+	for {
+		p, ok := e.(*ast.ParenExpr)
+		if !ok {
+			return e
+		}
+		e = p.X
+	}
+}

vendor/golang.org/x/tools/go/buildutil/allpackages.go

@@ -0,0 +1,198 @@
+// 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 buildutil provides utilities related to the go/build
+// package in the standard library.
+//
+// All I/O is done via the build.Context file system interface, which must
+// be concurrency-safe.
+package buildutil // import "golang.org/x/tools/go/buildutil"
+
+import (
+	"go/build"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"sync"
+)
+
+// AllPackages returns the package path of each Go package in any source
+// directory of the specified build context (e.g. $GOROOT or an element
+// of $GOPATH).  Errors are ignored.  The results are sorted.
+// All package paths are canonical, and thus may contain "/vendor/".
+//
+// The result may include import paths for directories that contain no
+// *.go files, such as "archive" (in $GOROOT/src).
+//
+// All I/O is done via the build.Context file system interface,
+// which must be concurrency-safe.
+//
+func AllPackages(ctxt *build.Context) []string {
+	var list []string
+	ForEachPackage(ctxt, func(pkg string, _ error) {
+		list = append(list, pkg)
+	})
+	sort.Strings(list)
+	return list
+}
+
+// ForEachPackage calls the found function with the package path of
+// each Go package it finds in any source directory of the specified
+// build context (e.g. $GOROOT or an element of $GOPATH).
+// All package paths are canonical, and thus may contain "/vendor/".
+//
+// If the package directory exists but could not be read, the second
+// argument to the found function provides the error.
+//
+// All I/O is done via the build.Context file system interface,
+// which must be concurrency-safe.
+//
+func ForEachPackage(ctxt *build.Context, found func(importPath string, err error)) {
+	ch := make(chan item)
+
+	var wg sync.WaitGroup
+	for _, root := range ctxt.SrcDirs() {
+		root := root
+		wg.Add(1)
+		go func() {
+			allPackages(ctxt, root, ch)
+			wg.Done()
+		}()
+	}
+	go func() {
+		wg.Wait()
+		close(ch)
+	}()
+
+	// All calls to found occur in the caller's goroutine.
+	for i := range ch {
+		found(i.importPath, i.err)
+	}
+}
+
+type item struct {
+	importPath string
+	err        error // (optional)
+}
+
+// We use a process-wide counting semaphore to limit
+// the number of parallel calls to ReadDir.
+var ioLimit = make(chan bool, 20)
+
+func allPackages(ctxt *build.Context, root string, ch chan<- item) {
+	root = filepath.Clean(root) + string(os.PathSeparator)
+
+	var wg sync.WaitGroup
+
+	var walkDir func(dir string)
+	walkDir = func(dir string) {
+		// Avoid .foo, _foo, and testdata directory trees.
+		base := filepath.Base(dir)
+		if base == "" || base[0] == '.' || base[0] == '_' || base == "testdata" {
+			return
+		}
+
+		pkg := filepath.ToSlash(strings.TrimPrefix(dir, root))
+
+		// Prune search if we encounter any of these import paths.
+		switch pkg {
+		case "builtin":
+			return
+		}
+
+		ioLimit <- true
+		files, err := ReadDir(ctxt, dir)
+		<-ioLimit
+		if pkg != "" || err != nil {
+			ch <- item{pkg, err}
+		}
+		for _, fi := range files {
+			fi := fi
+			if fi.IsDir() {
+				wg.Add(1)
+				go func() {
+					walkDir(filepath.Join(dir, fi.Name()))
+					wg.Done()
+				}()
+			}
+		}
+	}
+
+	walkDir(root)
+	wg.Wait()
+}
+
+// ExpandPatterns returns the set of packages matched by patterns,
+// which may have the following forms:
+//
+//		golang.org/x/tools/cmd/guru     # a single package
+//		golang.org/x/tools/...          # all packages beneath dir
+//		...                             # the entire workspace.
+//
+// Order is significant: a pattern preceded by '-' removes matching
+// packages from the set.  For example, these patterns match all encoding
+// packages except encoding/xml:
+//
+// 	encoding/... -encoding/xml
+//
+// A trailing slash in a pattern is ignored.  (Path components of Go
+// package names are separated by slash, not the platform's path separator.)
+//
+func ExpandPatterns(ctxt *build.Context, patterns []string) map[string]bool {
+	// TODO(adonovan): support other features of 'go list':
+	// - "std"/"cmd"/"all" meta-packages
+	// - "..." not at the end of a pattern
+	// - relative patterns using "./" or "../" prefix
+
+	pkgs := make(map[string]bool)
+	doPkg := func(pkg string, neg bool) {
+		if neg {
+			delete(pkgs, pkg)
+		} else {
+			pkgs[pkg] = true
+		}
+	}
+
+	// Scan entire workspace if wildcards are present.
+	// TODO(adonovan): opt: scan only the necessary subtrees of the workspace.
+	var all []string
+	for _, arg := range patterns {
+		if strings.HasSuffix(arg, "...") {
+			all = AllPackages(ctxt)
+			break
+		}
+	}
+
+	for _, arg := range patterns {
+		if arg == "" {
+			continue
+		}
+
+		neg := arg[0] == '-'
+		if neg {
+			arg = arg[1:]
+		}
+
+		if arg == "..." {
+			// ... matches all packages
+			for _, pkg := range all {
+				doPkg(pkg, neg)
+			}
+		} else if dir := strings.TrimSuffix(arg, "/..."); dir != arg {
+			// dir/... matches all packages beneath dir
+			for _, pkg := range all {
+				if strings.HasPrefix(pkg, dir) &&
+					(len(pkg) == len(dir) || pkg[len(dir)] == '/') {
+					doPkg(pkg, neg)
+				}
+			}
+		} else {
+			// single package
+			doPkg(strings.TrimSuffix(arg, "/"), neg)
+		}
+	}
+
+	return pkgs
+}

vendor/golang.org/x/tools/go/buildutil/allpackages_test.go

@@ -0,0 +1,83 @@
+// 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.
+
+// Incomplete source tree on Android.
+
+// +build !android
+
+package buildutil_test
+
+import (
+	"go/build"
+	"runtime"
+	"sort"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/buildutil"
+)
+
+func TestAllPackages(t *testing.T) {
+	if runtime.Compiler == "gccgo" {
+		t.Skip("gccgo has no standard packages")
+	}
+
+	all := buildutil.AllPackages(&build.Default)
+
+	set := make(map[string]bool)
+	for _, pkg := range all {
+		set[pkg] = true
+	}
+
+	const wantAtLeast = 250
+	if len(all) < wantAtLeast {
+		t.Errorf("Found only %d packages, want at least %d", len(all), wantAtLeast)
+	}
+
+	for _, want := range []string{"fmt", "crypto/sha256", "golang.org/x/tools/go/buildutil"} {
+		if !set[want] {
+			t.Errorf("Package %q not found; got %s", want, all)
+		}
+	}
+}
+
+func TestExpandPatterns(t *testing.T) {
+	tree := make(map[string]map[string]string)
+	for _, pkg := range []string{
+		"encoding",
+		"encoding/xml",
+		"encoding/hex",
+		"encoding/json",
+		"fmt",
+	} {
+		tree[pkg] = make(map[string]string)
+	}
+	ctxt := buildutil.FakeContext(tree)
+
+	for _, test := range []struct {
+		patterns string
+		want     string
+	}{
+		{"", ""},
+		{"fmt", "fmt"},
+		{"nosuchpkg", "nosuchpkg"},
+		{"nosuchdir/...", ""},
+		{"...", "encoding encoding/hex encoding/json encoding/xml fmt"},
+		{"encoding/... -encoding/xml", "encoding encoding/hex encoding/json"},
+		{"... -encoding/...", "fmt"},
+		{"encoding", "encoding"},
+		{"encoding/", "encoding"},
+	} {
+		var pkgs []string
+		for pkg := range buildutil.ExpandPatterns(ctxt, strings.Fields(test.patterns)) {
+			pkgs = append(pkgs, pkg)
+		}
+		sort.Strings(pkgs)
+		got := strings.Join(pkgs, " ")
+		if got != test.want {
+			t.Errorf("ExpandPatterns(%s) = %s, want %s",
+				test.patterns, got, test.want)
+		}
+	}
+}

vendor/golang.org/x/tools/go/buildutil/fakecontext.go

@@ -0,0 +1,109 @@
+package buildutil
+
+import (
+	"fmt"
+	"go/build"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+)
+
+// FakeContext returns a build.Context for the fake file tree specified
+// by pkgs, which maps package import paths to a mapping from file base
+// names to contents.
+//
+// The fake Context has a GOROOT of "/go" and no GOPATH, and overrides
+// the necessary file access methods to read from memory instead of the
+// real file system.
+//
+// Unlike a real file tree, the fake one has only two levels---packages
+// and files---so ReadDir("/go/src/") returns all packages under
+// /go/src/ including, for instance, "math" and "math/big".
+// ReadDir("/go/src/math/big") would return all the files in the
+// "math/big" package.
+//
+func FakeContext(pkgs map[string]map[string]string) *build.Context {
+	clean := func(filename string) string {
+		f := path.Clean(filepath.ToSlash(filename))
+		// Removing "/go/src" while respecting segment
+		// boundaries has this unfortunate corner case:
+		if f == "/go/src" {
+			return ""
+		}
+		return strings.TrimPrefix(f, "/go/src/")
+	}
+
+	ctxt := build.Default // copy
+	ctxt.GOROOT = "/go"
+	ctxt.GOPATH = ""
+	ctxt.Compiler = "gc"
+	ctxt.IsDir = func(dir string) bool {
+		dir = clean(dir)
+		if dir == "" {
+			return true // needed by (*build.Context).SrcDirs
+		}
+		return pkgs[dir] != nil
+	}
+	ctxt.ReadDir = func(dir string) ([]os.FileInfo, error) {
+		dir = clean(dir)
+		var fis []os.FileInfo
+		if dir == "" {
+			// enumerate packages
+			for importPath := range pkgs {
+				fis = append(fis, fakeDirInfo(importPath))
+			}
+		} else {
+			// enumerate files of package
+			for basename := range pkgs[dir] {
+				fis = append(fis, fakeFileInfo(basename))
+			}
+		}
+		sort.Sort(byName(fis))
+		return fis, nil
+	}
+	ctxt.OpenFile = func(filename string) (io.ReadCloser, error) {
+		filename = clean(filename)
+		dir, base := path.Split(filename)
+		content, ok := pkgs[path.Clean(dir)][base]
+		if !ok {
+			return nil, fmt.Errorf("file not found: %s", filename)
+		}
+		return ioutil.NopCloser(strings.NewReader(content)), nil
+	}
+	ctxt.IsAbsPath = func(path string) bool {
+		path = filepath.ToSlash(path)
+		// Don't rely on the default (filepath.Path) since on
+		// Windows, it reports virtual paths as non-absolute.
+		return strings.HasPrefix(path, "/")
+	}
+	return &ctxt
+}
+
+type byName []os.FileInfo
+
+func (s byName) Len() int           { return len(s) }
+func (s byName) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s byName) Less(i, j int) bool { return s[i].Name() < s[j].Name() }
+
+type fakeFileInfo string
+
+func (fi fakeFileInfo) Name() string    { return string(fi) }
+func (fakeFileInfo) Sys() interface{}   { return nil }
+func (fakeFileInfo) ModTime() time.Time { return time.Time{} }
+func (fakeFileInfo) IsDir() bool        { return false }
+func (fakeFileInfo) Size() int64        { return 0 }
+func (fakeFileInfo) Mode() os.FileMode  { return 0644 }
+
+type fakeDirInfo string
+
+func (fd fakeDirInfo) Name() string    { return string(fd) }
+func (fakeDirInfo) Sys() interface{}   { return nil }
+func (fakeDirInfo) ModTime() time.Time { return time.Time{} }
+func (fakeDirInfo) IsDir() bool        { return true }
+func (fakeDirInfo) Size() int64        { return 0 }
+func (fakeDirInfo) Mode() os.FileMode  { return 0755 }

vendor/golang.org/x/tools/go/buildutil/overlay.go

@@ -0,0 +1,103 @@
+// Copyright 2016 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 buildutil
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/build"
+	"io"
+	"io/ioutil"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// OverlayContext overlays a build.Context with additional files from
+// a map. Files in the map take precedence over other files.
+//
+// In addition to plain string comparison, two file names are
+// considered equal if their base names match and their directory
+// components point at the same directory on the file system. That is,
+// symbolic links are followed for directories, but not files.
+//
+// A common use case for OverlayContext is to allow editors to pass in
+// a set of unsaved, modified files.
+//
+// Currently, only the Context.OpenFile function will respect the
+// overlay. This may change in the future.
+func OverlayContext(orig *build.Context, overlay map[string][]byte) *build.Context {
+	// TODO(dominikh): Implement IsDir, HasSubdir and ReadDir
+
+	rc := func(data []byte) (io.ReadCloser, error) {
+		return ioutil.NopCloser(bytes.NewBuffer(data)), nil
+	}
+
+	copy := *orig // make a copy
+	ctxt := &copy
+	ctxt.OpenFile = func(path string) (io.ReadCloser, error) {
+		// Fast path: names match exactly.
+		if content, ok := overlay[path]; ok {
+			return rc(content)
+		}
+
+		// Slow path: check for same file under a different
+		// alias, perhaps due to a symbolic link.
+		for filename, content := range overlay {
+			if sameFile(path, filename) {
+				return rc(content)
+			}
+		}
+
+		return OpenFile(orig, path)
+	}
+	return ctxt
+}
+
+// ParseOverlayArchive parses an archive containing Go files and their
+// contents. The result is intended to be used with OverlayContext.
+//
+//
+// Archive format
+//
+// The archive consists of a series of files. Each file consists of a
+// name, a decimal file size and the file contents, separated by
+// newlinews. No newline follows after the file contents.
+func ParseOverlayArchive(archive io.Reader) (map[string][]byte, error) {
+	overlay := make(map[string][]byte)
+	r := bufio.NewReader(archive)
+	for {
+		// Read file name.
+		filename, err := r.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				break // OK
+			}
+			return nil, fmt.Errorf("reading archive file name: %v", err)
+		}
+		filename = filepath.Clean(strings.TrimSpace(filename))
+
+		// Read file size.
+		sz, err := r.ReadString('\n')
+		if err != nil {
+			return nil, fmt.Errorf("reading size of archive file %s: %v", filename, err)
+		}
+		sz = strings.TrimSpace(sz)
+		size, err := strconv.ParseUint(sz, 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("parsing size of archive file %s: %v", filename, err)
+		}
+
+		// Read file content.
+		content := make([]byte, size)
+		if _, err := io.ReadFull(r, content); err != nil {
+			return nil, fmt.Errorf("reading archive file %s: %v", filename, err)
+		}
+		overlay[filename] = content
+	}
+
+	return overlay, nil
+}

vendor/golang.org/x/tools/go/buildutil/overlay_test.go

@@ -0,0 +1,70 @@
+package buildutil_test
+
+import (
+	"go/build"
+	"io/ioutil"
+	"reflect"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/buildutil"
+)
+
+func TestParseOverlayArchive(t *testing.T) {
+	var tt = []struct {
+		in     string
+		out    map[string][]byte
+		hasErr bool
+	}{
+		{
+			"a.go\n5\n12345",
+			map[string][]byte{"a.go": []byte("12345")},
+			false,
+		},
+		{
+			"a.go\n5\n1234",
+			nil,
+			true,
+		},
+		{
+			"a.go\n5\n12345b.go\n4\n1234",
+			map[string][]byte{"a.go": []byte("12345"), "b.go": []byte("1234")},
+			false,
+		},
+	}
+
+	for _, test := range tt {
+		got, err := buildutil.ParseOverlayArchive(strings.NewReader(test.in))
+		if err == nil && test.hasErr {
+			t.Errorf("expected error for %q", test.in)
+		}
+		if err != nil && !test.hasErr {
+			t.Errorf("unexpected error %v for %q", err, test.in)
+		}
+		if !reflect.DeepEqual(got, test.out) {
+			t.Errorf("got %#v, want %#v", got, test.out)
+		}
+	}
+}
+
+func TestOverlay(t *testing.T) {
+	ctx := &build.Default
+	ov := map[string][]byte{
+		"/somewhere/a.go": []byte("file contents"),
+	}
+	names := []string{"/somewhere/a.go", "/somewhere//a.go"}
+	ctx = buildutil.OverlayContext(ctx, ov)
+	for _, name := range names {
+		f, err := buildutil.OpenFile(ctx, name)
+		if err != nil {
+			t.Errorf("unexpected error %v", err)
+		}
+		b, err := ioutil.ReadAll(f)
+		if err != nil {
+			t.Errorf("unexpected error %v", err)
+		}
+		if got, expected := string(b), string(ov["/somewhere/a.go"]); got != expected {
+			t.Errorf("read %q, expected %q", got, expected)
+		}
+	}
+}

vendor/golang.org/x/tools/go/buildutil/tags.go

@@ -0,0 +1,75 @@
+package buildutil
+
+// This logic was copied from stringsFlag from $GOROOT/src/cmd/go/build.go.
+
+import "fmt"
+
+const TagsFlagDoc = "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"
+
+// TagsFlag is an implementation of the flag.Value and flag.Getter interfaces that parses
+// a flag value in the same manner as go build's -tags flag and
+// populates a []string slice.
+//
+// See $GOROOT/src/go/build/doc.go for description of build tags.
+// See $GOROOT/src/cmd/go/doc.go for description of 'go build -tags' flag.
+//
+// Example:
+// 	flag.Var((*buildutil.TagsFlag)(&build.Default.BuildTags), "tags", buildutil.TagsFlagDoc)
+type TagsFlag []string
+
+func (v *TagsFlag) Set(s string) error {
+	var err error
+	*v, err = splitQuotedFields(s)
+	if *v == nil {
+		*v = []string{}
+	}
+	return err
+}
+
+func (v *TagsFlag) Get() interface{} { return *v }
+
+func splitQuotedFields(s string) ([]string, error) {
+	// Split fields allowing '' or "" around elements.
+	// Quotes further inside the string do not count.
+	var f []string
+	for len(s) > 0 {
+		for len(s) > 0 && isSpaceByte(s[0]) {
+			s = s[1:]
+		}
+		if len(s) == 0 {
+			break
+		}
+		// Accepted quoted string. No unescaping inside.
+		if s[0] == '"' || s[0] == '\'' {
+			quote := s[0]
+			s = s[1:]
+			i := 0
+			for i < len(s) && s[i] != quote {
+				i++
+			}
+			if i >= len(s) {
+				return nil, fmt.Errorf("unterminated %c string", quote)
+			}
+			f = append(f, s[:i])
+			s = s[i+1:]
+			continue
+		}
+		i := 0
+		for i < len(s) && !isSpaceByte(s[i]) {
+			i++
+		}
+		f = append(f, s[:i])
+		s = s[i:]
+	}
+	return f, nil
+}
+
+func (v *TagsFlag) String() string {
+	return "<tagsFlag>"
+}
+
+func isSpaceByte(c byte) bool {
+	return c == ' ' || c == '\t' || c == '\n' || c == '\r'
+}

vendor/golang.org/x/tools/go/buildutil/tags_test.go

@@ -0,0 +1,28 @@
+package buildutil_test
+
+import (
+	"flag"
+	"go/build"
+	"reflect"
+	"testing"
+
+	"golang.org/x/tools/go/buildutil"
+)
+
+func TestTags(t *testing.T) {
+	f := flag.NewFlagSet("TestTags", flag.PanicOnError)
+	var ctxt build.Context
+	f.Var((*buildutil.TagsFlag)(&ctxt.BuildTags), "tags", buildutil.TagsFlagDoc)
+	f.Parse([]string{"-tags", ` 'one'"two"	'three "four"'`, "rest"})
+
+	// BuildTags
+	want := []string{"one", "two", "three \"four\""}
+	if !reflect.DeepEqual(ctxt.BuildTags, want) {
+		t.Errorf("BuildTags = %q, want %q", ctxt.BuildTags, want)
+	}
+
+	// Args()
+	if want := []string{"rest"}; !reflect.DeepEqual(f.Args(), want) {
+		t.Errorf("f.Args() = %q, want %q", f.Args(), want)
+	}
+}

vendor/golang.org/x/tools/go/buildutil/util.go

@@ -0,0 +1,212 @@
+// 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 buildutil
+
+import (
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/parser"
+	"go/token"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+// ParseFile behaves like parser.ParseFile,
+// but uses the build context's file system interface, if any.
+//
+// If file is not absolute (as defined by IsAbsPath), the (dir, file)
+// components are joined using JoinPath; dir must be absolute.
+//
+// The displayPath function, if provided, is used to transform the
+// filename that will be attached to the ASTs.
+//
+// TODO(adonovan): call this from go/loader.parseFiles when the tree thaws.
+//
+func ParseFile(fset *token.FileSet, ctxt *build.Context, displayPath func(string) string, dir string, file string, mode parser.Mode) (*ast.File, error) {
+	if !IsAbsPath(ctxt, file) {
+		file = JoinPath(ctxt, dir, file)
+	}
+	rd, err := OpenFile(ctxt, file)
+	if err != nil {
+		return nil, err
+	}
+	defer rd.Close() // ignore error
+	if displayPath != nil {
+		file = displayPath(file)
+	}
+	return parser.ParseFile(fset, file, rd, mode)
+}
+
+// ContainingPackage returns the package containing filename.
+//
+// If filename is not absolute, it is interpreted relative to working directory dir.
+// All I/O is via the build context's file system interface, if any.
+//
+// The '...Files []string' fields of the resulting build.Package are not
+// populated (build.FindOnly mode).
+//
+func ContainingPackage(ctxt *build.Context, dir, filename string) (*build.Package, error) {
+	if !IsAbsPath(ctxt, filename) {
+		filename = JoinPath(ctxt, dir, filename)
+	}
+
+	// We must not assume the file tree uses
+	// "/" always,
+	// `\` always,
+	// or os.PathSeparator (which varies by platform),
+	// but to make any progress, we are forced to assume that
+	// paths will not use `\` unless the PathSeparator
+	// is also `\`, thus we can rely on filepath.ToSlash for some sanity.
+
+	dirSlash := path.Dir(filepath.ToSlash(filename)) + "/"
+
+	// We assume that no source root (GOPATH[i] or GOROOT) contains any other.
+	for _, srcdir := range ctxt.SrcDirs() {
+		srcdirSlash := filepath.ToSlash(srcdir) + "/"
+		if importPath, ok := HasSubdir(ctxt, srcdirSlash, dirSlash); ok {
+			return ctxt.Import(importPath, dir, build.FindOnly)
+		}
+	}
+
+	return nil, fmt.Errorf("can't find package containing %s", filename)
+}
+
+// -- Effective methods of file system interface -------------------------
+
+// (go/build.Context defines these as methods, but does not export them.)
+
+// hasSubdir calls ctxt.HasSubdir (if not nil) or else uses
+// the local file system to answer the question.
+func HasSubdir(ctxt *build.Context, root, dir string) (rel string, ok bool) {
+	if f := ctxt.HasSubdir; f != nil {
+		return f(root, dir)
+	}
+
+	// Try using paths we received.
+	if rel, ok = hasSubdir(root, dir); ok {
+		return
+	}
+
+	// Try expanding symlinks and comparing
+	// expanded against unexpanded and
+	// expanded against expanded.
+	rootSym, _ := filepath.EvalSymlinks(root)
+	dirSym, _ := filepath.EvalSymlinks(dir)
+
+	if rel, ok = hasSubdir(rootSym, dir); ok {
+		return
+	}
+	if rel, ok = hasSubdir(root, dirSym); ok {
+		return
+	}
+	return hasSubdir(rootSym, dirSym)
+}
+
+func hasSubdir(root, dir string) (rel string, ok bool) {
+	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
+}
+
+// FileExists returns true if the specified file exists,
+// using the build context's file system interface.
+func FileExists(ctxt *build.Context, path string) bool {
+	if ctxt.OpenFile != nil {
+		r, err := ctxt.OpenFile(path)
+		if err != nil {
+			return false
+		}
+		r.Close() // ignore error
+		return true
+	}
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// OpenFile behaves like os.Open,
+// but uses the build context's file system interface, if any.
+func OpenFile(ctxt *build.Context, path string) (io.ReadCloser, error) {
+	if ctxt.OpenFile != nil {
+		return ctxt.OpenFile(path)
+	}
+	return os.Open(path)
+}
+
+// IsAbsPath behaves like filepath.IsAbs,
+// but uses the build context's file system interface, if any.
+func IsAbsPath(ctxt *build.Context, path string) bool {
+	if ctxt.IsAbsPath != nil {
+		return ctxt.IsAbsPath(path)
+	}
+	return filepath.IsAbs(path)
+}
+
+// JoinPath behaves like filepath.Join,
+// but uses the build context's file system interface, if any.
+func JoinPath(ctxt *build.Context, path ...string) string {
+	if ctxt.JoinPath != nil {
+		return ctxt.JoinPath(path...)
+	}
+	return filepath.Join(path...)
+}
+
+// IsDir behaves like os.Stat plus IsDir,
+// but uses the build context's file system interface, if any.
+func IsDir(ctxt *build.Context, path string) bool {
+	if ctxt.IsDir != nil {
+		return ctxt.IsDir(path)
+	}
+	fi, err := os.Stat(path)
+	return err == nil && fi.IsDir()
+}
+
+// ReadDir behaves like ioutil.ReadDir,
+// but uses the build context's file system interface, if any.
+func ReadDir(ctxt *build.Context, path string) ([]os.FileInfo, error) {
+	if ctxt.ReadDir != nil {
+		return ctxt.ReadDir(path)
+	}
+	return ioutil.ReadDir(path)
+}
+
+// SplitPathList behaves like filepath.SplitList,
+// but uses the build context's file system interface, if any.
+func SplitPathList(ctxt *build.Context, s string) []string {
+	if ctxt.SplitPathList != nil {
+		return ctxt.SplitPathList(s)
+	}
+	return filepath.SplitList(s)
+}
+
+// sameFile returns true if x and y have the same basename and denote
+// the same file.
+//
+func sameFile(x, y string) bool {
+	if path.Clean(x) == path.Clean(y) {
+		return true
+	}
+	if filepath.Base(x) == filepath.Base(y) { // (optimisation)
+		if xi, err := os.Stat(x); err == nil {
+			if yi, err := os.Stat(y); err == nil {
+				return os.SameFile(xi, yi)
+			}
+		}
+	}
+	return false
+}

vendor/golang.org/x/tools/go/buildutil/util_test.go

@@ -0,0 +1,85 @@
+// 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 buildutil_test
+
+import (
+	"go/build"
+	"io/ioutil"
+	"os"
+	"runtime"
+	"testing"
+
+	"golang.org/x/tools/go/buildutil"
+)
+
+func TestContainingPackage(t *testing.T) {
+	if runtime.Compiler == "gccgo" {
+		t.Skip("gccgo has no GOROOT")
+	}
+
+	// unvirtualized:
+	goroot := runtime.GOROOT()
+	gopath := gopathContainingTools(t)
+
+	type Test struct {
+		gopath, filename, wantPkg string
+	}
+
+	tests := []Test{
+		{gopath, goroot + "/src/fmt/print.go", "fmt"},
+		{gopath, goroot + "/src/encoding/json/foo.go", "encoding/json"},
+		{gopath, goroot + "/src/encoding/missing/foo.go", "(not found)"},
+		{gopath, gopath + "/src/golang.org/x/tools/go/buildutil/util_test.go",
+			"golang.org/x/tools/go/buildutil"},
+	}
+
+	if runtime.GOOS != "windows" && runtime.GOOS != "plan9" {
+		// Make a symlink to gopath for test
+		tmp, err := ioutil.TempDir(os.TempDir(), "go")
+		if err != nil {
+			t.Errorf("Unable to create a temporary directory in %s", os.TempDir())
+		}
+
+		defer os.RemoveAll(tmp)
+
+		// symlink between $GOPATH/src and /tmp/go/src
+		// in order to test all possible symlink cases
+		if err := os.Symlink(gopath+"/src", tmp+"/src"); err != nil {
+			t.Fatal(err)
+		}
+		tests = append(tests, []Test{
+			{gopath, tmp + "/src/golang.org/x/tools/go/buildutil/util_test.go", "golang.org/x/tools/go/buildutil"},
+			{tmp, gopath + "/src/golang.org/x/tools/go/buildutil/util_test.go", "golang.org/x/tools/go/buildutil"},
+			{tmp, tmp + "/src/golang.org/x/tools/go/buildutil/util_test.go", "golang.org/x/tools/go/buildutil"},
+		}...)
+	}
+
+	for _, test := range tests {
+		var got string
+		var buildContext = build.Default
+		buildContext.GOPATH = test.gopath
+		bp, err := buildutil.ContainingPackage(&buildContext, ".", test.filename)
+		if err != nil {
+			got = "(not found)"
+		} else {
+			got = bp.ImportPath
+		}
+		if got != test.wantPkg {
+			t.Errorf("ContainingPackage(%q) = %s, want %s", test.filename, got, test.wantPkg)
+		}
+	}
+
+	// TODO(adonovan): test on virtualized GOPATH too.
+}
+
+// gopathContainingTools returns the path of the GOPATH workspace
+// with golang.org/x/tools, or fails the test if it can't locate it.
+func gopathContainingTools(t *testing.T) string {
+	p, err := build.Import("golang.org/x/tools", "", build.FindOnly)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return p.Root
+}

vendor/golang.org/x/tools/go/buildutil/util_windows_test.go

@@ -0,0 +1,48 @@
+// Copyright 2015 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 buildutil_test
+
+import (
+	"fmt"
+	"go/build"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/buildutil"
+)
+
+func testContainingPackageCaseFold(file, want string) error {
+	bp, err := buildutil.ContainingPackage(&build.Default, ".", file)
+	if err != nil {
+		return err
+	}
+	if got := bp.ImportPath; got != want {
+		return fmt.Errorf("ContainingPackage(%q) = %s, want %s", file, got, want)
+	}
+	return nil
+}
+
+func TestContainingPackageCaseFold(t *testing.T) {
+	path := filepath.Join(runtime.GOROOT(), `src\fmt\print.go`)
+	err := testContainingPackageCaseFold(path, "fmt")
+	if err != nil {
+		t.Error(err)
+	}
+	vol := filepath.VolumeName(path)
+	if len(vol) != 2 || vol[1] != ':' {
+		t.Fatalf("GOROOT path has unexpected volume name: %v", vol)
+	}
+	rest := path[len(vol):]
+	err = testContainingPackageCaseFold(strings.ToUpper(vol)+rest, "fmt")
+	if err != nil {
+		t.Error(err)
+	}
+	err = testContainingPackageCaseFold(strings.ToLower(vol)+rest, "fmt")
+	if err != nil {
+		t.Error(err)
+	}
+}

vendor/golang.org/x/tools/go/callgraph/callgraph.go

@@ -0,0 +1,129 @@
+// 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.
+
+/*
+
+Package callgraph defines the call graph and various algorithms
+and utilities to operate on it.
+
+A call graph is a labelled directed graph whose nodes represent
+functions and whose edge labels represent syntactic function call
+sites.  The presence of a labelled edge (caller, site, callee)
+indicates that caller may call callee at the specified call site.
+
+A call graph is a multigraph: it may contain multiple edges (caller,
+*, callee) connecting the same pair of nodes, so long as the edges
+differ by label; this occurs when one function calls another function
+from multiple call sites.  Also, it may contain multiple edges
+(caller, site, *) that differ only by callee; this indicates a
+polymorphic call.
+
+A SOUND call graph is one that overapproximates the dynamic calling
+behaviors of the program in all possible executions.  One call graph
+is more PRECISE than another if it is a smaller overapproximation of
+the dynamic behavior.
+
+All call graphs have a synthetic root node which is responsible for
+calling main() and init().
+
+Calls to built-in functions (e.g. panic, println) are not represented
+in the call graph; they are treated like built-in operators of the
+language.
+
+*/
+package callgraph // import "golang.org/x/tools/go/callgraph"
+
+// TODO(adonovan): add a function to eliminate wrappers from the
+// callgraph, preserving topology.
+// More generally, we could eliminate "uninteresting" nodes such as
+// nodes from packages we don't care about.
+
+import (
+	"fmt"
+	"go/token"
+
+	"golang.org/x/tools/go/ssa"
+)
+
+// A Graph represents a call graph.
+//
+// A graph may contain nodes that are not reachable from the root.
+// If the call graph is sound, such nodes indicate unreachable
+// functions.
+//
+type Graph struct {
+	Root  *Node                   // the distinguished root node
+	Nodes map[*ssa.Function]*Node // all nodes by function
+}
+
+// New returns a new Graph with the specified root node.
+func New(root *ssa.Function) *Graph {
+	g := &Graph{Nodes: make(map[*ssa.Function]*Node)}
+	g.Root = g.CreateNode(root)
+	return g
+}
+
+// CreateNode returns the Node for fn, creating it if not present.
+func (g *Graph) CreateNode(fn *ssa.Function) *Node {
+	n, ok := g.Nodes[fn]
+	if !ok {
+		n = &Node{Func: fn, ID: len(g.Nodes)}
+		g.Nodes[fn] = n
+	}
+	return n
+}
+
+// A Node represents a node in a call graph.
+type Node struct {
+	Func *ssa.Function // the function this node represents
+	ID   int           // 0-based sequence number
+	In   []*Edge       // unordered set of incoming call edges (n.In[*].Callee == n)
+	Out  []*Edge       // unordered set of outgoing call edges (n.Out[*].Caller == n)
+}
+
+func (n *Node) String() string {
+	return fmt.Sprintf("n%d:%s", n.ID, n.Func)
+}
+
+// A Edge represents an edge in the call graph.
+//
+// Site is nil for edges originating in synthetic or intrinsic
+// functions, e.g. reflect.Call or the root of the call graph.
+type Edge struct {
+	Caller *Node
+	Site   ssa.CallInstruction
+	Callee *Node
+}
+
+func (e Edge) String() string {
+	return fmt.Sprintf("%s --> %s", e.Caller, e.Callee)
+}
+
+func (e Edge) Description() string {
+	var prefix string
+	switch e.Site.(type) {
+	case nil:
+		return "synthetic call"
+	case *ssa.Go:
+		prefix = "concurrent "
+	case *ssa.Defer:
+		prefix = "deferred "
+	}
+	return prefix + e.Site.Common().Description()
+}
+
+func (e Edge) Pos() token.Pos {
+	if e.Site == nil {
+		return token.NoPos
+	}
+	return e.Site.Pos()
+}
+
+// AddEdge adds the edge (caller, site, callee) to the call graph.
+// Elimination of duplicate edges is the caller's responsibility.
+func AddEdge(caller *Node, site ssa.CallInstruction, callee *Node) {
+	e := &Edge{caller, site, callee}
+	callee.In = append(callee.In, e)
+	caller.Out = append(caller.Out, e)
+}

vendor/golang.org/x/tools/go/callgraph/cha/cha.go

@@ -0,0 +1,139 @@
+// 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 cha computes the call graph of a Go program using the Class
+// Hierarchy Analysis (CHA) algorithm.
+//
+// CHA was first described in "Optimization of Object-Oriented Programs
+// Using Static Class Hierarchy Analysis", Jeffrey Dean, David Grove,
+// and Craig Chambers, ECOOP'95.
+//
+// CHA is related to RTA (see go/callgraph/rta); the difference is that
+// CHA conservatively computes the entire "implements" relation between
+// interfaces and concrete types ahead of time, whereas RTA uses dynamic
+// programming to construct it on the fly as it encounters new functions
+// reachable from main.  CHA may thus include spurious call edges for
+// types that haven't been instantiated yet, or types that are never
+// instantiated.
+//
+// Since CHA conservatively assumes that all functions are address-taken
+// and all concrete types are put into interfaces, it is sound to run on
+// partial programs, such as libraries without a main or test function.
+//
+package cha // import "golang.org/x/tools/go/callgraph/cha"
+
+import (
+	"go/types"
+
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
+	"golang.org/x/tools/go/types/typeutil"
+)
+
+// CallGraph computes the call graph of the specified program using the
+// Class Hierarchy Analysis algorithm.
+//
+func CallGraph(prog *ssa.Program) *callgraph.Graph {
+	cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph
+
+	allFuncs := ssautil.AllFunctions(prog)
+
+	// funcsBySig contains all functions, keyed by signature.  It is
+	// the effective set of address-taken functions used to resolve
+	// a dynamic call of a particular signature.
+	var funcsBySig typeutil.Map // value is []*ssa.Function
+
+	// methodsByName contains all methods,
+	// grouped by name for efficient lookup.
+	// (methodsById would be better but not every SSA method has a go/types ID.)
+	methodsByName := make(map[string][]*ssa.Function)
+
+	// An imethod represents an interface method I.m.
+	// (There's no go/types object for it;
+	// a *types.Func may be shared by many interfaces due to interface embedding.)
+	type imethod struct {
+		I  *types.Interface
+		id string
+	}
+	// methodsMemo records, for every abstract method call I.m on
+	// interface type I, the set of concrete methods C.m of all
+	// types C that satisfy interface I.
+	//
+	// Abstract methods may be shared by several interfaces,
+	// hence we must pass I explicitly, not guess from m.
+	//
+	// methodsMemo is just a cache, so it needn't be a typeutil.Map.
+	methodsMemo := make(map[imethod][]*ssa.Function)
+	lookupMethods := func(I *types.Interface, m *types.Func) []*ssa.Function {
+		id := m.Id()
+		methods, ok := methodsMemo[imethod{I, id}]
+		if !ok {
+			for _, f := range methodsByName[m.Name()] {
+				C := f.Signature.Recv().Type() // named or *named
+				if types.Implements(C, I) {
+					methods = append(methods, f)
+				}
+			}
+			methodsMemo[imethod{I, id}] = methods
+		}
+		return methods
+	}
+
+	for f := range allFuncs {
+		if f.Signature.Recv() == nil {
+			// Package initializers can never be address-taken.
+			if f.Name() == "init" && f.Synthetic == "package initializer" {
+				continue
+			}
+			funcs, _ := funcsBySig.At(f.Signature).([]*ssa.Function)
+			funcs = append(funcs, f)
+			funcsBySig.Set(f.Signature, funcs)
+		} else {
+			methodsByName[f.Name()] = append(methodsByName[f.Name()], f)
+		}
+	}
+
+	addEdge := func(fnode *callgraph.Node, site ssa.CallInstruction, g *ssa.Function) {
+		gnode := cg.CreateNode(g)
+		callgraph.AddEdge(fnode, site, gnode)
+	}
+
+	addEdges := func(fnode *callgraph.Node, site ssa.CallInstruction, callees []*ssa.Function) {
+		// Because every call to a highly polymorphic and
+		// frequently used abstract method such as
+		// (io.Writer).Write is assumed to call every concrete
+		// Write method in the program, the call graph can
+		// contain a lot of duplication.
+		//
+		// TODO(adonovan): opt: consider factoring the callgraph
+		// API so that the Callers component of each edge is a
+		// slice of nodes, not a singleton.
+		for _, g := range callees {
+			addEdge(fnode, site, g)
+		}
+	}
+
+	for f := range allFuncs {
+		fnode := cg.CreateNode(f)
+		for _, b := range f.Blocks {
+			for _, instr := range b.Instrs {
+				if site, ok := instr.(ssa.CallInstruction); ok {
+					call := site.Common()
+					if call.IsInvoke() {
+						tiface := call.Value.Type().Underlying().(*types.Interface)
+						addEdges(fnode, site, lookupMethods(tiface, call.Method))
+					} else if g := call.StaticCallee(); g != nil {
+						addEdge(fnode, site, g)
+					} else if _, ok := call.Value.(*ssa.Builtin); !ok {
+						callees, _ := funcsBySig.At(call.Signature()).([]*ssa.Function)
+						addEdges(fnode, site, callees)
+					}
+				}
+			}
+		}
+	}
+
+	return cg
+}

vendor/golang.org/x/tools/go/callgraph/cha/cha_test.go

@@ -0,0 +1,111 @@
+// 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.
+
+// No testdata on Android.
+
+// +build !android
+
+package cha_test
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"io/ioutil"
+	"sort"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/callgraph/cha"
+	"golang.org/x/tools/go/loader"
+	"golang.org/x/tools/go/ssa/ssautil"
+)
+
+var inputs = []string{
+	"testdata/func.go",
+	"testdata/iface.go",
+	"testdata/recv.go",
+	"testdata/issue23925.go",
+}
+
+func expectation(f *ast.File) (string, token.Pos) {
+	for _, c := range f.Comments {
+		text := strings.TrimSpace(c.Text())
+		if t := strings.TrimPrefix(text, "WANT:\n"); t != text {
+			return t, c.Pos()
+		}
+	}
+	return "", token.NoPos
+}
+
+// TestCHA runs CHA on each file in inputs, prints the dynamic edges of
+// the call graph, and compares it with the golden results embedded in
+// the WANT comment at the end of the file.
+//
+func TestCHA(t *testing.T) {
+	for _, filename := range inputs {
+		content, err := ioutil.ReadFile(filename)
+		if err != nil {
+			t.Errorf("couldn't read file '%s': %s", filename, err)
+			continue
+		}
+
+		conf := loader.Config{
+			ParserMode: parser.ParseComments,
+		}
+		f, err := conf.ParseFile(filename, content)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		want, pos := expectation(f)
+		if pos == token.NoPos {
+			t.Errorf("No WANT: comment in %s", filename)
+			continue
+		}
+
+		conf.CreateFromFiles("main", f)
+		iprog, err := conf.Load()
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		prog := ssautil.CreateProgram(iprog, 0)
+		mainPkg := prog.Package(iprog.Created[0].Pkg)
+		prog.Build()
+
+		cg := cha.CallGraph(prog)
+
+		if got := printGraph(cg, mainPkg.Pkg); got != want {
+			t.Errorf("%s: got:\n%s\nwant:\n%s",
+				prog.Fset.Position(pos), got, want)
+		}
+	}
+}
+
+func printGraph(cg *callgraph.Graph, from *types.Package) string {
+	var edges []string
+	callgraph.GraphVisitEdges(cg, func(e *callgraph.Edge) error {
+		if strings.Contains(e.Description(), "dynamic") {
+			edges = append(edges, fmt.Sprintf("%s --> %s",
+				e.Caller.Func.RelString(from),
+				e.Callee.Func.RelString(from)))
+		}
+		return nil
+	})
+	sort.Strings(edges)
+
+	var buf bytes.Buffer
+	buf.WriteString("Dynamic calls\n")
+	for _, edge := range edges {
+		fmt.Fprintf(&buf, "  %s\n", edge)
+	}
+	return strings.TrimSpace(buf.String())
+}

vendor/golang.org/x/tools/go/callgraph/cha/testdata/func.go

@@ -0,0 +1,23 @@
+//+build ignore
+
+package main
+
+// Test of dynamic function calls; no interfaces.
+
+func A(int) {}
+
+var (
+	B = func(int) {}
+	C = func(int) {}
+)
+
+func f() {
+	pfn := B
+	pfn(0) // calls A, B, C, even though A is not even address-taken
+}
+
+// WANT:
+// Dynamic calls
+//   f --> A
+//   f --> init$1
+//   f --> init$2

vendor/golang.org/x/tools/go/callgraph/cha/testdata/iface.go

@@ -0,0 +1,65 @@
+//+build ignore
+
+package main
+
+// Test of interface calls.  None of the concrete types are ever
+// instantiated or converted to interfaces.
+
+type I interface {
+	f()
+}
+
+type J interface {
+	f()
+	g()
+}
+
+type C int // implements I
+
+func (*C) f()
+
+type D int // implements I and J
+
+func (*D) f()
+func (*D) g()
+
+func one(i I, j J) {
+	i.f() // calls *C and *D
+}
+
+func two(i I, j J) {
+	j.f() // calls *D (but not *C, even though it defines method f)
+}
+
+func three(i I, j J) {
+	j.g() // calls *D
+}
+
+func four(i I, j J) {
+	Jf := J.f
+	if unknown {
+		Jf = nil // suppress SSA constant propagation
+	}
+	Jf(nil) // calls *D
+}
+
+func five(i I, j J) {
+	jf := j.f
+	if unknown {
+		jf = nil // suppress SSA constant propagation
+	}
+	jf() // calls *D
+}
+
+var unknown bool
+
+// WANT:
+// Dynamic calls
+//   (J).f$bound --> (*D).f
+//   (J).f$thunk --> (*D).f
+//   five --> (J).f$bound
+//   four --> (J).f$thunk
+//   one --> (*C).f
+//   one --> (*D).f
+//   three --> (*D).g
+//   two --> (*D).f

vendor/golang.org/x/tools/go/callgraph/cha/testdata/issue23925.go

@@ -0,0 +1,38 @@
+package main
+
+// Regression test for https://github.com/golang/go/issues/23925
+
+type stringFlagImpl string
+
+func (*stringFlagImpl) Set(s string) error { return nil }
+
+type boolFlagImpl bool
+
+func (*boolFlagImpl) Set(s string) error { return nil }
+func (*boolFlagImpl) extra()             {}
+
+// A copy of flag.boolFlag interface, without a dependency.
+// Must appear first, so that it becomes the owner of the Set methods.
+type boolFlag interface {
+	flagValue
+	extra()
+}
+
+// A copy of flag.Value, without adding a dependency.
+type flagValue interface {
+	Set(string) error
+}
+
+func main() {
+	var x flagValue = new(stringFlagImpl)
+	x.Set("")
+
+	var y boolFlag = new(boolFlagImpl)
+	y.Set("")
+}
+
+// WANT:
+// Dynamic calls
+//   main --> (*boolFlagImpl).Set
+//   main --> (*boolFlagImpl).Set
+//   main --> (*stringFlagImpl).Set

vendor/golang.org/x/tools/go/callgraph/cha/testdata/recv.go

@@ -0,0 +1,37 @@
+//+build ignore
+
+package main
+
+type I interface {
+	f()
+}
+
+type J interface {
+	g()
+}
+
+type C int // C and *C implement I; *C implements J
+
+func (C) f()
+func (*C) g()
+
+type D int // *D implements I and J
+
+func (*D) f()
+func (*D) g()
+
+func f(i I) {
+	i.f() // calls C, *C, *D
+}
+
+func g(j J) {
+	j.g() // calls *C, *D
+}
+
+// WANT:
+// Dynamic calls
+//   f --> (*C).f
+//   f --> (*D).f
+//   f --> (C).f
+//   g --> (*C).g
+//   g --> (*D).g

vendor/golang.org/x/tools/go/callgraph/rta/rta.go

@@ -0,0 +1,459 @@
+// 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.
+
+// This package provides Rapid Type Analysis (RTA) for Go, a fast
+// algorithm for call graph construction and discovery of reachable code
+// (and hence dead code) and runtime types.  The algorithm was first
+// described in:
+//
+// David F. Bacon and Peter F. Sweeney. 1996.
+// Fast static analysis of C++ virtual function calls. (OOPSLA '96)
+// http://doi.acm.org/10.1145/236337.236371
+//
+// The algorithm uses dynamic programming to tabulate the cross-product
+// of the set of known "address taken" functions with the set of known
+// dynamic calls of the same type.  As each new address-taken function
+// is discovered, call graph edges are added from each known callsite,
+// and as each new call site is discovered, call graph edges are added
+// from it to each known address-taken function.
+//
+// A similar approach is used for dynamic calls via interfaces: it
+// tabulates the cross-product of the set of known "runtime types",
+// i.e. types that may appear in an interface value, or be derived from
+// one via reflection, with the set of known "invoke"-mode dynamic
+// calls.  As each new "runtime type" is discovered, call edges are
+// added from the known call sites, and as each new call site is
+// discovered, call graph edges are added to each compatible
+// method.
+//
+// In addition, we must consider all exported methods of any runtime type
+// as reachable, since they may be called via reflection.
+//
+// Each time a newly added call edge causes a new function to become
+// reachable, the code of that function is analyzed for more call sites,
+// address-taken functions, and runtime types.  The process continues
+// until a fixed point is achieved.
+//
+// The resulting call graph is less precise than one produced by pointer
+// analysis, but the algorithm is much faster.  For example, running the
+// cmd/callgraph tool on its own source takes ~2.1s for RTA and ~5.4s
+// for points-to analysis.
+//
+package rta // import "golang.org/x/tools/go/callgraph/rta"
+
+// TODO(adonovan): test it by connecting it to the interpreter and
+// replacing all "unreachable" functions by a special intrinsic, and
+// ensure that that intrinsic is never called.
+
+import (
+	"fmt"
+	"go/types"
+
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/types/typeutil"
+)
+
+// A Result holds the results of Rapid Type Analysis, which includes the
+// set of reachable functions/methods, runtime types, and the call graph.
+//
+type Result struct {
+	// CallGraph is the discovered callgraph.
+	// It does not include edges for calls made via reflection.
+	CallGraph *callgraph.Graph
+
+	// Reachable contains the set of reachable functions and methods.
+	// This includes exported methods of runtime types, since
+	// they may be accessed via reflection.
+	// The value indicates whether the function is address-taken.
+	//
+	// (We wrap the bool in a struct to avoid inadvertent use of
+	// "if Reachable[f] {" to test for set membership.)
+	Reachable map[*ssa.Function]struct{ AddrTaken bool }
+
+	// RuntimeTypes contains the set of types that are needed at
+	// runtime, for interfaces or reflection.
+	//
+	// The value indicates whether the type is inaccessible to reflection.
+	// Consider:
+	// 	type A struct{B}
+	// 	fmt.Println(new(A))
+	// Types *A, A and B are accessible to reflection, but the unnamed
+	// type struct{B} is not.
+	RuntimeTypes typeutil.Map
+}
+
+// Working state of the RTA algorithm.
+type rta struct {
+	result *Result
+
+	prog *ssa.Program
+
+	worklist []*ssa.Function // list of functions to visit
+
+	// addrTakenFuncsBySig contains all address-taken *Functions, grouped by signature.
+	// Keys are *types.Signature, values are map[*ssa.Function]bool sets.
+	addrTakenFuncsBySig typeutil.Map
+
+	// dynCallSites contains all dynamic "call"-mode call sites, grouped by signature.
+	// Keys are *types.Signature, values are unordered []ssa.CallInstruction.
+	dynCallSites typeutil.Map
+
+	// invokeSites contains all "invoke"-mode call sites, grouped by interface.
+	// Keys are *types.Interface (never *types.Named),
+	// Values are unordered []ssa.CallInstruction sets.
+	invokeSites typeutil.Map
+
+	// The following two maps together define the subset of the
+	// m:n "implements" relation needed by the algorithm.
+
+	// concreteTypes maps each concrete type to the set of interfaces that it implements.
+	// Keys are types.Type, values are unordered []*types.Interface.
+	// Only concrete types used as MakeInterface operands are included.
+	concreteTypes typeutil.Map
+
+	// interfaceTypes maps each interface type to
+	// the set of concrete types that implement it.
+	// Keys are *types.Interface, values are unordered []types.Type.
+	// Only interfaces used in "invoke"-mode CallInstructions are included.
+	interfaceTypes typeutil.Map
+}
+
+// addReachable marks a function as potentially callable at run-time,
+// and ensures that it gets processed.
+func (r *rta) addReachable(f *ssa.Function, addrTaken bool) {
+	reachable := r.result.Reachable
+	n := len(reachable)
+	v := reachable[f]
+	if addrTaken {
+		v.AddrTaken = true
+	}
+	reachable[f] = v
+	if len(reachable) > n {
+		// First time seeing f.  Add it to the worklist.
+		r.worklist = append(r.worklist, f)
+	}
+}
+
+// addEdge adds the specified call graph edge, and marks it reachable.
+// addrTaken indicates whether to mark the callee as "address-taken".
+func (r *rta) addEdge(site ssa.CallInstruction, callee *ssa.Function, addrTaken bool) {
+	r.addReachable(callee, addrTaken)
+
+	if g := r.result.CallGraph; g != nil {
+		if site.Parent() == nil {
+			panic(site)
+		}
+		from := g.CreateNode(site.Parent())
+		to := g.CreateNode(callee)
+		callgraph.AddEdge(from, site, to)
+	}
+}
+
+// ---------- addrTakenFuncs × dynCallSites ----------
+
+// visitAddrTakenFunc is called each time we encounter an address-taken function f.
+func (r *rta) visitAddrTakenFunc(f *ssa.Function) {
+	// Create two-level map (Signature -> Function -> bool).
+	S := f.Signature
+	funcs, _ := r.addrTakenFuncsBySig.At(S).(map[*ssa.Function]bool)
+	if funcs == nil {
+		funcs = make(map[*ssa.Function]bool)
+		r.addrTakenFuncsBySig.Set(S, funcs)
+	}
+	if !funcs[f] {
+		// First time seeing f.
+		funcs[f] = true
+
+		// If we've seen any dyncalls of this type, mark it reachable,
+		// and add call graph edges.
+		sites, _ := r.dynCallSites.At(S).([]ssa.CallInstruction)
+		for _, site := range sites {
+			r.addEdge(site, f, true)
+		}
+	}
+}
+
+// visitDynCall is called each time we encounter a dynamic "call"-mode call.
+func (r *rta) visitDynCall(site ssa.CallInstruction) {
+	S := site.Common().Signature()
+
+	// Record the call site.
+	sites, _ := r.dynCallSites.At(S).([]ssa.CallInstruction)
+	r.dynCallSites.Set(S, append(sites, site))
+
+	// For each function of signature S that we know is address-taken,
+	// mark it reachable.  We'll add the callgraph edges later.
+	funcs, _ := r.addrTakenFuncsBySig.At(S).(map[*ssa.Function]bool)
+	for g := range funcs {
+		r.addEdge(site, g, true)
+	}
+}
+
+// ---------- concrete types × invoke sites ----------
+
+// addInvokeEdge is called for each new pair (site, C) in the matrix.
+func (r *rta) addInvokeEdge(site ssa.CallInstruction, C types.Type) {
+	// Ascertain the concrete method of C to be called.
+	imethod := site.Common().Method
+	cmethod := r.prog.MethodValue(r.prog.MethodSets.MethodSet(C).Lookup(imethod.Pkg(), imethod.Name()))
+	r.addEdge(site, cmethod, true)
+}
+
+// visitInvoke is called each time the algorithm encounters an "invoke"-mode call.
+func (r *rta) visitInvoke(site ssa.CallInstruction) {
+	I := site.Common().Value.Type().Underlying().(*types.Interface)
+
+	// Record the invoke site.
+	sites, _ := r.invokeSites.At(I).([]ssa.CallInstruction)
+	r.invokeSites.Set(I, append(sites, site))
+
+	// Add callgraph edge for each existing
+	// address-taken concrete type implementing I.
+	for _, C := range r.implementations(I) {
+		r.addInvokeEdge(site, C)
+	}
+}
+
+// ---------- main algorithm ----------
+
+// visitFunc processes function f.
+func (r *rta) visitFunc(f *ssa.Function) {
+	var space [32]*ssa.Value // preallocate space for common case
+
+	for _, b := range f.Blocks {
+		for _, instr := range b.Instrs {
+			rands := instr.Operands(space[:0])
+
+			switch instr := instr.(type) {
+			case ssa.CallInstruction:
+				call := instr.Common()
+				if call.IsInvoke() {
+					r.visitInvoke(instr)
+				} else if g := call.StaticCallee(); g != nil {
+					r.addEdge(instr, g, false)
+				} else if _, ok := call.Value.(*ssa.Builtin); !ok {
+					r.visitDynCall(instr)
+				}
+
+				// Ignore the call-position operand when
+				// looking for address-taken Functions.
+				// Hack: assume this is rands[0].
+				rands = rands[1:]
+
+			case *ssa.MakeInterface:
+				r.addRuntimeType(instr.X.Type(), false)
+			}
+
+			// Process all address-taken functions.
+			for _, op := range rands {
+				if g, ok := (*op).(*ssa.Function); ok {
+					r.visitAddrTakenFunc(g)
+				}
+			}
+		}
+	}
+}
+
+// Analyze performs Rapid Type Analysis, starting at the specified root
+// functions.  It returns nil if no roots were specified.
+//
+// If buildCallGraph is true, Result.CallGraph will contain a call
+// graph; otherwise, only the other fields (reachable functions) are
+// populated.
+//
+func Analyze(roots []*ssa.Function, buildCallGraph bool) *Result {
+	if len(roots) == 0 {
+		return nil
+	}
+
+	r := &rta{
+		result: &Result{Reachable: make(map[*ssa.Function]struct{ AddrTaken bool })},
+		prog:   roots[0].Prog,
+	}
+
+	if buildCallGraph {
+		// TODO(adonovan): change callgraph API to eliminate the
+		// notion of a distinguished root node.  Some callgraphs
+		// have many roots, or none.
+		r.result.CallGraph = callgraph.New(roots[0])
+	}
+
+	hasher := typeutil.MakeHasher()
+	r.result.RuntimeTypes.SetHasher(hasher)
+	r.addrTakenFuncsBySig.SetHasher(hasher)
+	r.dynCallSites.SetHasher(hasher)
+	r.invokeSites.SetHasher(hasher)
+	r.concreteTypes.SetHasher(hasher)
+	r.interfaceTypes.SetHasher(hasher)
+
+	// Visit functions, processing their instructions, and adding
+	// new functions to the worklist, until a fixed point is
+	// reached.
+	var shadow []*ssa.Function // for efficiency, we double-buffer the worklist
+	r.worklist = append(r.worklist, roots...)
+	for len(r.worklist) > 0 {
+		shadow, r.worklist = r.worklist, shadow[:0]
+		for _, f := range shadow {
+			r.visitFunc(f)
+		}
+	}
+	return r.result
+}
+
+// interfaces(C) returns all currently known interfaces implemented by C.
+func (r *rta) interfaces(C types.Type) []*types.Interface {
+	// Ascertain set of interfaces C implements
+	// and update 'implements' relation.
+	var ifaces []*types.Interface
+	r.interfaceTypes.Iterate(func(I types.Type, concs interface{}) {
+		if I := I.(*types.Interface); types.Implements(C, I) {
+			concs, _ := concs.([]types.Type)
+			r.interfaceTypes.Set(I, append(concs, C))
+			ifaces = append(ifaces, I)
+		}
+	})
+	r.concreteTypes.Set(C, ifaces)
+	return ifaces
+}
+
+// implementations(I) returns all currently known concrete types that implement I.
+func (r *rta) implementations(I *types.Interface) []types.Type {
+	var concs []types.Type
+	if v := r.interfaceTypes.At(I); v != nil {
+		concs = v.([]types.Type)
+	} else {
+		// First time seeing this interface.
+		// Update the 'implements' relation.
+		r.concreteTypes.Iterate(func(C types.Type, ifaces interface{}) {
+			if types.Implements(C, I) {
+				ifaces, _ := ifaces.([]*types.Interface)
+				r.concreteTypes.Set(C, append(ifaces, I))
+				concs = append(concs, C)
+			}
+		})
+		r.interfaceTypes.Set(I, concs)
+	}
+	return concs
+}
+
+// addRuntimeType is called for each concrete type that can be the
+// dynamic type of some interface or reflect.Value.
+// Adapted from needMethods in go/ssa/builder.go
+//
+func (r *rta) addRuntimeType(T types.Type, skip bool) {
+	if prev, ok := r.result.RuntimeTypes.At(T).(bool); ok {
+		if skip && !prev {
+			r.result.RuntimeTypes.Set(T, skip)
+		}
+		return
+	}
+	r.result.RuntimeTypes.Set(T, skip)
+
+	mset := r.prog.MethodSets.MethodSet(T)
+
+	if _, ok := T.Underlying().(*types.Interface); !ok {
+		// T is a new concrete type.
+		for i, n := 0, mset.Len(); i < n; i++ {
+			sel := mset.At(i)
+			m := sel.Obj()
+
+			if m.Exported() {
+				// Exported methods are always potentially callable via reflection.
+				r.addReachable(r.prog.MethodValue(sel), true)
+			}
+		}
+
+		// Add callgraph edge for each existing dynamic
+		// "invoke"-mode call via that interface.
+		for _, I := range r.interfaces(T) {
+			sites, _ := r.invokeSites.At(I).([]ssa.CallInstruction)
+			for _, site := range sites {
+				r.addInvokeEdge(site, T)
+			}
+		}
+	}
+
+	// Precondition: T is not a method signature (*Signature with Recv()!=nil).
+	// Recursive case: skip => don't call makeMethods(T).
+	// Each package maintains its own set of types it has visited.
+
+	var n *types.Named
+	switch T := T.(type) {
+	case *types.Named:
+		n = T
+	case *types.Pointer:
+		n, _ = T.Elem().(*types.Named)
+	}
+	if n != nil {
+		owner := n.Obj().Pkg()
+		if owner == nil {
+			return // built-in error type
+		}
+	}
+
+	// Recursion over signatures of each exported method.
+	for i := 0; i < mset.Len(); i++ {
+		if mset.At(i).Obj().Exported() {
+			sig := mset.At(i).Type().(*types.Signature)
+			r.addRuntimeType(sig.Params(), true)  // skip the Tuple itself
+			r.addRuntimeType(sig.Results(), true) // skip the Tuple itself
+		}
+	}
+
+	switch t := T.(type) {
+	case *types.Basic:
+		// nop
+
+	case *types.Interface:
+		// nop---handled by recursion over method set.
+
+	case *types.Pointer:
+		r.addRuntimeType(t.Elem(), false)
+
+	case *types.Slice:
+		r.addRuntimeType(t.Elem(), false)
+
+	case *types.Chan:
+		r.addRuntimeType(t.Elem(), false)
+
+	case *types.Map:
+		r.addRuntimeType(t.Key(), false)
+		r.addRuntimeType(t.Elem(), false)
+
+	case *types.Signature:
+		if t.Recv() != nil {
+			panic(fmt.Sprintf("Signature %s has Recv %s", t, t.Recv()))
+		}
+		r.addRuntimeType(t.Params(), true)  // skip the Tuple itself
+		r.addRuntimeType(t.Results(), true) // skip the Tuple itself
+
+	case *types.Named:
+		// A pointer-to-named type can be derived from a named
+		// type via reflection.  It may have methods too.
+		r.addRuntimeType(types.NewPointer(T), false)
+
+		// Consider 'type T struct{S}' where S has methods.
+		// Reflection provides no way to get from T to struct{S},
+		// only to S, so the method set of struct{S} is unwanted,
+		// so set 'skip' flag during recursion.
+		r.addRuntimeType(t.Underlying(), true)
+
+	case *types.Array:
+		r.addRuntimeType(t.Elem(), false)
+
+	case *types.Struct:
+		for i, n := 0, t.NumFields(); i < n; i++ {
+			r.addRuntimeType(t.Field(i).Type(), false)
+		}
+
+	case *types.Tuple:
+		for i, n := 0, t.Len(); i < n; i++ {
+			r.addRuntimeType(t.At(i).Type(), false)
+		}
+
+	default:
+		panic(T)
+	}
+}

vendor/golang.org/x/tools/go/callgraph/rta/rta_test.go

@@ -0,0 +1,139 @@
+// 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.
+
+// No testdata on Android.
+
+// +build !android
+
+package rta_test
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"io/ioutil"
+	"sort"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/callgraph/rta"
+	"golang.org/x/tools/go/loader"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
+)
+
+var inputs = []string{
+	"testdata/func.go",
+	"testdata/rtype.go",
+	"testdata/iface.go",
+}
+
+func expectation(f *ast.File) (string, token.Pos) {
+	for _, c := range f.Comments {
+		text := strings.TrimSpace(c.Text())
+		if t := strings.TrimPrefix(text, "WANT:\n"); t != text {
+			return t, c.Pos()
+		}
+	}
+	return "", token.NoPos
+}
+
+// TestRTA runs RTA on each file in inputs, prints the results, and
+// compares it with the golden results embedded in the WANT comment at
+// the end of the file.
+//
+// The results string consists of two parts: the set of dynamic call
+// edges, "f --> g", one per line, and the set of reachable functions,
+// one per line.  Each set is sorted.
+//
+func TestRTA(t *testing.T) {
+	for _, filename := range inputs {
+		content, err := ioutil.ReadFile(filename)
+		if err != nil {
+			t.Errorf("couldn't read file '%s': %s", filename, err)
+			continue
+		}
+
+		conf := loader.Config{
+			ParserMode: parser.ParseComments,
+		}
+		f, err := conf.ParseFile(filename, content)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		want, pos := expectation(f)
+		if pos == token.NoPos {
+			t.Errorf("No WANT: comment in %s", filename)
+			continue
+		}
+
+		conf.CreateFromFiles("main", f)
+		iprog, err := conf.Load()
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		prog := ssautil.CreateProgram(iprog, 0)
+		mainPkg := prog.Package(iprog.Created[0].Pkg)
+		prog.Build()
+
+		res := rta.Analyze([]*ssa.Function{
+			mainPkg.Func("main"),
+			mainPkg.Func("init"),
+		}, true)
+
+		if got := printResult(res, mainPkg.Pkg); got != want {
+			t.Errorf("%s: got:\n%s\nwant:\n%s",
+				prog.Fset.Position(pos), got, want)
+		}
+	}
+}
+
+func printResult(res *rta.Result, from *types.Package) string {
+	var buf bytes.Buffer
+
+	writeSorted := func(ss []string) {
+		sort.Strings(ss)
+		for _, s := range ss {
+			fmt.Fprintf(&buf, "  %s\n", s)
+		}
+	}
+
+	buf.WriteString("Dynamic calls\n")
+	var edges []string
+	callgraph.GraphVisitEdges(res.CallGraph, func(e *callgraph.Edge) error {
+		if strings.Contains(e.Description(), "dynamic") {
+			edges = append(edges, fmt.Sprintf("%s --> %s",
+				e.Caller.Func.RelString(from),
+				e.Callee.Func.RelString(from)))
+		}
+		return nil
+	})
+	writeSorted(edges)
+
+	buf.WriteString("Reachable functions\n")
+	var reachable []string
+	for f := range res.Reachable {
+		reachable = append(reachable, f.RelString(from))
+	}
+	writeSorted(reachable)
+
+	buf.WriteString("Reflect types\n")
+	var rtypes []string
+	res.RuntimeTypes.Iterate(func(key types.Type, value interface{}) {
+		if value == false { // accessible to reflection
+			rtypes = append(rtypes, types.TypeString(key, types.RelativeTo(from)))
+		}
+	})
+	writeSorted(rtypes)
+
+	return strings.TrimSpace(buf.String())
+}

vendor/golang.org/x/tools/go/callgraph/rta/testdata/func.go

@@ -0,0 +1,37 @@
+//+build ignore
+
+package main
+
+// Test of dynamic function calls.
+// No interfaces, so no runtime/reflect types.
+
+func A1() {
+	A2(0)
+}
+
+func A2(int) {} // not address-taken
+
+func B() {} // unreachable
+
+var (
+	C = func(int) {}
+	D = func(int) {}
+)
+
+func main() {
+	A1()
+
+	pfn := C
+	pfn(0) // calls C and D but not A2 (same sig but not address-taken)
+}
+
+// WANT:
+// Dynamic calls
+//   main --> init$1
+//   main --> init$2
+// Reachable functions
+//   A1
+//   A2
+//   init$1
+//   init$2
+// Reflect types

vendor/golang.org/x/tools/go/callgraph/rta/testdata/iface.go

@@ -0,0 +1,79 @@
+//+build ignore
+
+package main
+
+// Test of interface calls.
+
+func use(interface{})
+
+type A byte // instantiated but not a reflect type
+
+func (A) f() {} // called directly
+func (A) F() {} // unreachable
+
+type B int // a reflect type
+
+func (*B) f() {} // reachable via interface invoke
+func (*B) F() {} // reachable: exported method of reflect type
+
+type B2 int // a reflect type, and *B2 also
+
+func (B2) f() {} // reachable via interface invoke
+func (B2) g() {} // reachable: exported method of reflect type
+
+type C string // not instantiated
+
+func (C) f() {} // unreachable
+func (C) F() {} // unreachable
+
+type D uint // instantiated only in dead code
+
+func (D) f() {} // unreachable
+func (D) F() {} // unreachable
+
+func main() {
+	A(0).f()
+
+	use(new(B))
+	use(B2(0))
+
+	var i interface {
+		f()
+	}
+	i.f() // calls (*B).f, (*B2).f and (B2.f)
+
+	live()
+}
+
+func live() {
+	var j interface {
+		f()
+		g()
+	}
+	j.f() // calls (B2).f and (*B2).f but not (*B).f (no g method).
+}
+
+func dead() {
+	use(D(0))
+}
+
+// WANT:
+// Dynamic calls
+//   live --> (*B2).f
+//   live --> (B2).f
+//   main --> (*B).f
+//   main --> (*B2).f
+//   main --> (B2).f
+// Reachable functions
+//   (*B).F
+//   (*B).f
+//   (*B2).f
+//   (A).f
+//   (B2).f
+//   live
+//   use
+// Reflect types
+//   *B
+//   *B2
+//   B
+//   B2

vendor/golang.org/x/tools/go/callgraph/rta/testdata/rtype.go

@@ -0,0 +1,35 @@
+//+build ignore
+
+package main
+
+// Test of runtime types (types for which descriptors are needed).
+
+func use(interface{})
+
+type A byte // neither A nor byte are runtime types
+
+type B struct{ x uint } // B and uint are runtime types, but not the struct
+
+func main() {
+	var x int // not a runtime type
+	print(x)
+
+	var y string // runtime type due to interface conversion
+	use(y)
+
+	use(struct{ uint64 }{}) // struct is a runtime type
+
+	use(new(B)) // *B is a runtime type
+}
+
+// WANT:
+// Dynamic calls
+// Reachable functions
+//   use
+// Reflect types
+//   *B
+//   B
+//   string
+//   struct{uint64}
+//   uint
+//   uint64

vendor/golang.org/x/tools/go/callgraph/static/static.go

@@ -0,0 +1,35 @@
+// Package static computes the call graph of a Go program containing
+// only static call edges.
+package static // import "golang.org/x/tools/go/callgraph/static"
+
+import (
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/ssa"
+	"golang.org/x/tools/go/ssa/ssautil"
+)
+
+// CallGraph computes the call graph of the specified program
+// considering only static calls.
+//
+func CallGraph(prog *ssa.Program) *callgraph.Graph {
+	cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph
+
+	// TODO(adonovan): opt: use only a single pass over the ssa.Program.
+	// TODO(adonovan): opt: this is slower than RTA (perhaps because
+	// the lower precision means so many edges are allocated)!
+	for f := range ssautil.AllFunctions(prog) {
+		fnode := cg.CreateNode(f)
+		for _, b := range f.Blocks {
+			for _, instr := range b.Instrs {
+				if site, ok := instr.(ssa.CallInstruction); ok {
+					if g := site.Common().StaticCallee(); g != nil {
+						gnode := cg.CreateNode(g)
+						callgraph.AddEdge(fnode, site, gnode)
+					}
+				}
+			}
+		}
+	}
+
+	return cg
+}

vendor/golang.org/x/tools/go/callgraph/static/static_test.go

@@ -0,0 +1,88 @@
+// 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 static_test
+
+import (
+	"fmt"
+	"go/parser"
+	"reflect"
+	"sort"
+	"testing"
+
+	"golang.org/x/tools/go/callgraph"
+	"golang.org/x/tools/go/callgraph/static"
+	"golang.org/x/tools/go/loader"
+	"golang.org/x/tools/go/ssa/ssautil"
+)
+
+const input = `package P
+
+type C int
+func (C) f()
+
+type I interface{f()}
+
+func f() {
+	p := func() {}
+	g()
+	p() // SSA constant propagation => static
+
+	if unknown {
+		p = h
+	}
+	p() // dynamic
+
+	C(0).f()
+}
+
+func g() {
+	var i I = C(0)
+	i.f()
+}
+
+func h()
+
+var unknown bool
+`
+
+func TestStatic(t *testing.T) {
+	conf := loader.Config{ParserMode: parser.ParseComments}
+	f, err := conf.ParseFile("P.go", input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	conf.CreateFromFiles("P", f)
+	iprog, err := conf.Load()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	P := iprog.Created[0].Pkg
+
+	prog := ssautil.CreateProgram(iprog, 0)
+	prog.Build()
+
+	cg := static.CallGraph(prog)
+
+	var edges []string
+	callgraph.GraphVisitEdges(cg, func(e *callgraph.Edge) error {
+		edges = append(edges, fmt.Sprintf("%s -> %s",
+			e.Caller.Func.RelString(P),
+			e.Callee.Func.RelString(P)))
+		return nil
+	})
+	sort.Strings(edges)
+
+	want := []string{
+		"(*C).f -> (C).f",
+		"f -> (C).f",
+		"f -> f$1",
+		"f -> g",
+	}
+	if !reflect.DeepEqual(edges, want) {
+		t.Errorf("Got edges %v, want %v", edges, want)
+	}
+}

vendor/golang.org/x/tools/go/callgraph/util.go

@@ -0,0 +1,181 @@
+// 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.
+
+package callgraph
+
+import "golang.org/x/tools/go/ssa"
+
+// This file provides various utilities over call graphs, such as
+// visitation and path search.
+
+// CalleesOf returns a new set containing all direct callees of the
+// caller node.
+//
+func CalleesOf(caller *Node) map[*Node]bool {
+	callees := make(map[*Node]bool)
+	for _, e := range caller.Out {
+		callees[e.Callee] = true
+	}
+	return callees
+}
+
+// GraphVisitEdges visits all the edges in graph g in depth-first order.
+// The edge function is called for each edge in postorder.  If it
+// returns non-nil, visitation stops and GraphVisitEdges returns that
+// value.
+//
+func GraphVisitEdges(g *Graph, edge func(*Edge) error) error {
+	seen := make(map[*Node]bool)
+	var visit func(n *Node) error
+	visit = func(n *Node) error {
+		if !seen[n] {
+			seen[n] = true
+			for _, e := range n.Out {
+				if err := visit(e.Callee); err != nil {
+					return err
+				}
+				if err := edge(e); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	for _, n := range g.Nodes {
+		if err := visit(n); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// PathSearch finds an arbitrary path starting at node start and
+// ending at some node for which isEnd() returns true.  On success,
+// PathSearch returns the path as an ordered list of edges; on
+// failure, it returns nil.
+//
+func PathSearch(start *Node, isEnd func(*Node) bool) []*Edge {
+	stack := make([]*Edge, 0, 32)
+	seen := make(map[*Node]bool)
+	var search func(n *Node) []*Edge
+	search = func(n *Node) []*Edge {
+		if !seen[n] {
+			seen[n] = true
+			if isEnd(n) {
+				return stack
+			}
+			for _, e := range n.Out {
+				stack = append(stack, e) // push
+				if found := search(e.Callee); found != nil {
+					return found
+				}
+				stack = stack[:len(stack)-1] // pop
+			}
+		}
+		return nil
+	}
+	return search(start)
+}
+
+// DeleteSyntheticNodes removes from call graph g all nodes for
+// synthetic functions (except g.Root and package initializers),
+// preserving the topology.  In effect, calls to synthetic wrappers
+// are "inlined".
+//
+func (g *Graph) DeleteSyntheticNodes() {
+	// Measurements on the standard library and go.tools show that
+	// resulting graph has ~15% fewer nodes and 4-8% fewer edges
+	// than the input.
+	//
+	// Inlining a wrapper of in-degree m, out-degree n adds m*n
+	// and removes m+n edges.  Since most wrappers are monomorphic
+	// (n=1) this results in a slight reduction.  Polymorphic
+	// wrappers (n>1), e.g. from embedding an interface value
+	// inside a struct to satisfy some interface, cause an
+	// increase in the graph, but they seem to be uncommon.
+
+	// Hash all existing edges to avoid creating duplicates.
+	edges := make(map[Edge]bool)
+	for _, cgn := range g.Nodes {
+		for _, e := range cgn.Out {
+			edges[*e] = true
+		}
+	}
+	for fn, cgn := range g.Nodes {
+		if cgn == g.Root || fn.Synthetic == "" || isInit(cgn.Func) {
+			continue // keep
+		}
+		for _, eIn := range cgn.In {
+			for _, eOut := range cgn.Out {
+				newEdge := Edge{eIn.Caller, eIn.Site, eOut.Callee}
+				if edges[newEdge] {
+					continue // don't add duplicate
+				}
+				AddEdge(eIn.Caller, eIn.Site, eOut.Callee)
+				edges[newEdge] = true
+			}
+		}
+		g.DeleteNode(cgn)
+	}
+}
+
+func isInit(fn *ssa.Function) bool {
+	return fn.Pkg != nil && fn.Pkg.Func("init") == fn
+}
+
+// DeleteNode removes node n and its edges from the graph g.
+// (NB: not efficient for batch deletion.)
+func (g *Graph) DeleteNode(n *Node) {
+	n.deleteIns()
+	n.deleteOuts()
+	delete(g.Nodes, n.Func)
+}
+
+// deleteIns deletes all incoming edges to n.
+func (n *Node) deleteIns() {
+	for _, e := range n.In {
+		removeOutEdge(e)
+	}
+	n.In = nil
+}
+
+// deleteOuts deletes all outgoing edges from n.
+func (n *Node) deleteOuts() {
+	for _, e := range n.Out {
+		removeInEdge(e)
+	}
+	n.Out = nil
+}
+
+// removeOutEdge removes edge.Caller's outgoing edge 'edge'.
+func removeOutEdge(edge *Edge) {
+	caller := edge.Caller
+	n := len(caller.Out)
+	for i, e := range caller.Out {
+		if e == edge {
+			// Replace it with the final element and shrink the slice.
+			caller.Out[i] = caller.Out[n-1]
+			caller.Out[n-1] = nil // aid GC
+			caller.Out = caller.Out[:n-1]
+			return
+		}
+	}
+	panic("edge not found: " + edge.String())
+}
+
+// removeInEdge removes edge.Callee's incoming edge 'edge'.
+func removeInEdge(edge *Edge) {
+	caller := edge.Callee
+	n := len(caller.In)
+	for i, e := range caller.In {
+		if e == edge {
+			// Replace it with the final element and shrink the slice.
+			caller.In[i] = caller.In[n-1]
+			caller.In[n-1] = nil // aid GC
+			caller.In = caller.In[:n-1]
+			return
+		}
+	}
+	panic("edge not found: " + edge.String())
+}

vendor/golang.org/x/tools/go/gccgoexportdata/gccgoexportdata.go

@@ -0,0 +1,129 @@
+// Copyright 2016 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 gccgoexportdata provides functions for reading export data
+// files containing type information produced by the gccgo compiler.
+//
+// This package is a stop-gap until such time as gccgo uses the same
+// export data format as gc; see Go issue 17573. Once that occurs, this
+// package will be deprecated and eventually deleted.
+package gccgoexportdata
+
+// TODO(adonovan): add Find, Write, Importer to the API,
+// for symmetry with gcexportdata.
+
+import (
+	"bytes"
+	"debug/elf"
+	"fmt"
+	"go/token"
+	"go/types"
+	"io"
+	"io/ioutil"
+	"strconv"
+	"strings"
+
+	"golang.org/x/tools/go/internal/gccgoimporter"
+)
+
+// CompilerInfo executes the specified gccgo compiler and returns
+// information about it: its version (e.g. "4.8.0"), its target triple
+// (e.g. "x86_64-unknown-linux-gnu"), and the list of directories it
+// searches to find standard packages. The given arguments are passed
+// directly to calls to the specified gccgo compiler.
+func CompilerInfo(gccgo string, args ...string) (version, triple string, dirs []string, err error) {
+	var inst gccgoimporter.GccgoInstallation
+	err = inst.InitFromDriver(gccgo, args...)
+	if err == nil {
+		version = inst.GccVersion
+		triple = inst.TargetTriple
+		dirs = inst.SearchPaths()
+	}
+	return
+}
+
+// NewReader returns a reader for the export data section of an object
+// (.o) or archive (.a) file read from r.
+func NewReader(r io.Reader) (io.Reader, error) {
+	data, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	// If the file is an archive, extract the first section.
+	const archiveMagic = "!<arch>\n"
+	if bytes.HasPrefix(data, []byte(archiveMagic)) {
+		section, err := firstSection(data[len(archiveMagic):])
+		if err != nil {
+			return nil, err
+		}
+		data = section
+	}
+
+	// Data contains an ELF file with a .go_export section.
+	// ELF magic number is "\x7fELF".
+	ef, err := elf.NewFile(bytes.NewReader(data))
+	if err != nil {
+		return nil, err
+	}
+	sec := ef.Section(".go_export")
+	if sec == nil {
+		return nil, fmt.Errorf("no .go_export section")
+	}
+	return sec.Open(), nil
+}
+
+// firstSection returns the contents of the first regular file in an ELF
+// archive (http://www.sco.com/developers/devspecs/gabi41.pdf, §7.2).
+func firstSection(a []byte) ([]byte, error) {
+	for len(a) >= 60 {
+		var hdr []byte
+		hdr, a = a[:60], a[60:]
+
+		name := strings.TrimSpace(string(hdr[:16]))
+
+		sizeStr := string(hdr[48:58])
+		size, err := strconv.Atoi(strings.TrimSpace(sizeStr))
+		if err != nil {
+			return nil, fmt.Errorf("invalid size: %q", sizeStr)
+		}
+
+		if len(a) < size {
+			return nil, fmt.Errorf("invalid section size: %d", size)
+		}
+
+		// The payload is padded to an even number of bytes.
+		var payload []byte
+		payload, a = a[:size], a[size+size&1:]
+
+		// Skip special files:
+		//   "/"           archive symbol table
+		//   "/SYM64/"     archive symbol table on e.g. s390x
+		//   "//"          archive string table (if any filename is >15 bytes)
+		if name == "/" || name == "/SYM64/" || name == "//" {
+			continue
+		}
+
+		return payload, nil
+	}
+	return nil, fmt.Errorf("archive has no regular sections")
+}
+
+// Read reads export data from in, decodes it, and returns type
+// information for the package.
+// The package name is specified by path.
+//
+// The FileSet parameter is currently unused but exists for symmetry
+// with gcexportdata.
+//
+// Read may inspect and add to the imports map to ensure that references
+// within the export data to other packages are consistent.  The caller
+// must ensure that imports[path] does not exist, or exists but is
+// incomplete (see types.Package.Complete), and Read inserts the
+// resulting package into this map entry.
+//
+// On return, the state of the reader is undefined.
+func Read(in io.Reader, _ *token.FileSet, imports map[string]*types.Package, path string) (*types.Package, error) {
+	return gccgoimporter.Parse(in, imports, path)
+}

vendor/golang.org/x/tools/go/gccgoexportdata/gccgoexportdata_test.go

@@ -0,0 +1,67 @@
+package gccgoexportdata_test
+
+import (
+	"go/types"
+	"os"
+	"testing"
+
+	"golang.org/x/tools/go/gccgoexportdata"
+)
+
+// Test ensures this package can read gccgo export data from the
+// .go_export from a standalone ELF file or such a file in an archive
+// library.
+//
+// The testdata/{short,long}.a ELF archive files were produced by:
+//
+//   $ echo 'package foo; func F()' > foo.go
+//   $ gccgo -c -fgo-pkgpath blah foo.go
+//   $ objcopy -j .go_export foo.o foo.gox
+//   $ ar q short.a foo.gox
+//   $ objcopy -j .go_export foo.o name-longer-than-16-bytes.gox
+//   $ ar q long.a name-longer-than-16-bytes.gox
+//
+// The file long.a contains an archive string table.
+//
+// The errors.gox file (an ELF object file) comes from the toolchain's
+// standard library.
+func Test(t *testing.T) {
+	for _, test := range []struct {
+		filename, path, member, wantType string
+	}{
+		{"testdata/errors.gox", "errors", "New", "func(text string) error"},
+		{"testdata/short.a", "short", "F", "func()"},
+		{"testdata/long.a", "long", "F", "func()"},
+	} {
+		t.Logf("filename = %s", test.filename)
+		f, err := os.Open(test.filename)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		defer f.Close()
+		r, err := gccgoexportdata.NewReader(f)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		imports := make(map[string]*types.Package)
+		pkg, err := gccgoexportdata.Read(r, nil, imports, test.path)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		// Check type of designated package member.
+		obj := pkg.Scope().Lookup(test.member)
+		if obj == nil {
+			t.Errorf("%s.%s not found", test.path, test.member)
+			continue
+		}
+		if obj.Type().String() != test.wantType {
+			t.Errorf("%s.%s.Type = %s, want %s",
+				test.path, test.member, obj.Type(), test.wantType)
+		}
+	}
+}

vendor/golang.org/x/tools/go/gcexportdata/example_test.go

@@ -0,0 +1,122 @@
+// Copyright 2016 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 go1.7
+// +build gc
+
+package gcexportdata_test
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"log"
+	"os"
+	"path/filepath"
+
+	"golang.org/x/tools/go/gcexportdata"
+)
+
+// ExampleRead uses gcexportdata.Read to load type information for the
+// "fmt" package from the fmt.a file produced by the gc compiler.
+func ExampleRead() {
+	// Find the export data file.
+	filename, path := gcexportdata.Find("fmt", "")
+	if filename == "" {
+		log.Fatalf("can't find export data for fmt")
+	}
+	fmt.Printf("Package path:       %s\n", path)
+	fmt.Printf("Export data:        %s\n", filepath.Base(filename))
+
+	// Open and read the file.
+	f, err := os.Open(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+	r, err := gcexportdata.NewReader(f)
+	if err != nil {
+		log.Fatalf("reading export data %s: %v", filename, err)
+	}
+
+	// Decode the export data.
+	fset := token.NewFileSet()
+	imports := make(map[string]*types.Package)
+	pkg, err := gcexportdata.Read(r, fset, imports, path)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Print package information.
+	fmt.Printf("Package members:    %s...\n", pkg.Scope().Names()[:5])
+	println := pkg.Scope().Lookup("Println")
+	posn := fset.Position(println.Pos())
+	posn.Line = 123 // make example deterministic
+	fmt.Printf("Println type:       %s\n", println.Type())
+	fmt.Printf("Println location:   %s\n", slashify(posn))
+
+	// Output:
+	//
+	// Package path:       fmt
+	// Export data:        fmt.a
+	// Package members:    [Errorf Formatter Fprint Fprintf Fprintln]...
+	// Println type:       func(a ...interface{}) (n int, err error)
+	// Println location:   $GOROOT/src/fmt/print.go:123:1
+}
+
+// ExampleNewImporter demonstrates usage of NewImporter to provide type
+// information for dependencies when type-checking Go source code.
+func ExampleNewImporter() {
+	const src = `package myscanner
+
+// choosing a package that is unlikely to change across releases
+import "text/scanner"
+
+const eof = scanner.EOF
+`
+	fset := token.NewFileSet()
+	f, err := parser.ParseFile(fset, "myscanner.go", src, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	packages := make(map[string]*types.Package)
+	imp := gcexportdata.NewImporter(fset, packages)
+	conf := types.Config{Importer: imp}
+	pkg, err := conf.Check("myscanner", fset, []*ast.File{f}, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// object from imported package
+	pi := packages["text/scanner"].Scope().Lookup("EOF")
+	fmt.Printf("const %s.%s %s = %s // %s\n",
+		pi.Pkg().Path(),
+		pi.Name(),
+		pi.Type(),
+		pi.(*types.Const).Val(),
+		slashify(fset.Position(pi.Pos())),
+	)
+
+	// object in source package
+	twopi := pkg.Scope().Lookup("eof")
+	fmt.Printf("const %s %s = %s // %s\n",
+		twopi.Name(),
+		twopi.Type(),
+		twopi.(*types.Const).Val(),
+		slashify(fset.Position(twopi.Pos())),
+	)
+
+	// Output:
+	//
+	// const text/scanner.EOF untyped int = -1 // $GOROOT/src/text/scanner/scanner.go:75:1
+	// const eof untyped int = -1 // myscanner.go:6:7
+}
+
+func slashify(posn token.Position) token.Position {
+	posn.Filename = filepath.ToSlash(posn.Filename) // for MS Windows portability
+	return posn
+}

vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go

@@ -0,0 +1,109 @@
+// Copyright 2016 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 gcexportdata provides functions for locating, reading, and
+// writing export data files containing type information produced by the
+// gc compiler.  This package supports go1.7 export data format and all
+// later versions.
+//
+// Although it might seem convenient for this package to live alongside
+// go/types in the standard library, this would cause version skew
+// problems for developer tools that use it, since they must be able to
+// consume the outputs of the gc compiler both before and after a Go
+// update such as from Go 1.7 to Go 1.8.  Because this package lives in
+// golang.org/x/tools, sites can update their version of this repo some
+// time before the Go 1.8 release and rebuild and redeploy their
+// developer tools, which will then be able to consume both Go 1.7 and
+// Go 1.8 export data files, so they will work before and after the
+// Go update. (See discussion at https://github.com/golang/go/issues/15651.)
+//
+package gcexportdata // import "golang.org/x/tools/go/gcexportdata"
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/token"
+	"go/types"
+	"io"
+	"io/ioutil"
+
+	"golang.org/x/tools/go/internal/gcimporter"
+)
+
+// Find returns the name of an object (.o) or archive (.a) file
+// containing type information for the specified import path,
+// using the workspace layout conventions of go/build.
+// If no file was found, an empty filename is returned.
+//
+// A relative srcDir is interpreted relative to the current working directory.
+//
+// Find also returns the package's resolved (canonical) import path,
+// reflecting the effects of srcDir and vendoring on importPath.
+func Find(importPath, srcDir string) (filename, path string) {
+	return gcimporter.FindPkg(importPath, srcDir)
+}
+
+// NewReader returns a reader for the export data section of an object
+// (.o) or archive (.a) file read from r.  The new reader may provide
+// additional trailing data beyond the end of the export data.
+func NewReader(r io.Reader) (io.Reader, error) {
+	buf := bufio.NewReader(r)
+	_, err := gcimporter.FindExportData(buf)
+	// If we ever switch to a zip-like archive format with the ToC
+	// at the end, we can return the correct portion of export data,
+	// but for now we must return the entire rest of the file.
+	return buf, err
+}
+
+// Read reads export data from in, decodes it, and returns type
+// information for the package.
+// The package name is specified by path.
+// File position information is added to fset.
+//
+// Read may inspect and add to the imports map to ensure that references
+// within the export data to other packages are consistent.  The caller
+// must ensure that imports[path] does not exist, or exists but is
+// incomplete (see types.Package.Complete), and Read inserts the
+// resulting package into this map entry.
+//
+// On return, the state of the reader is undefined.
+func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package, path string) (*types.Package, error) {
+	data, err := ioutil.ReadAll(in)
+	if err != nil {
+		return nil, fmt.Errorf("reading export data for %q: %v", path, err)
+	}
+
+	if bytes.HasPrefix(data, []byte("!<arch>")) {
+		return nil, fmt.Errorf("can't read export data for %q directly from an archive file (call gcexportdata.NewReader first to extract export data)", path)
+	}
+
+	// The App Engine Go runtime v1.6 uses the old export data format.
+	// TODO(adonovan): delete once v1.7 has been around for a while.
+	if bytes.HasPrefix(data, []byte("package ")) {
+		return gcimporter.ImportData(imports, path, path, bytes.NewReader(data))
+	}
+
+	// The indexed export format starts with an 'i'; the older
+	// binary export format starts with a 'c', 'd', or 'v'
+	// (from "version"). Select appropriate importer.
+	if len(data) > 0 && data[0] == 'i' {
+		_, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path)
+		return pkg, err
+	}
+
+	_, pkg, err := gcimporter.BImportData(fset, imports, data, path)
+	return pkg, err
+}
+
+// Write writes encoded type information for the specified package to out.
+// The FileSet provides file position information for named objects.
+func Write(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
+	b, err := gcimporter.BExportData(fset, pkg)
+	if err != nil {
+		return err
+	}
+	_, err = out.Write(b)
+	return err
+}

vendor/golang.org/x/tools/go/gcexportdata/gcexportdata_test.go

@@ -0,0 +1,41 @@
+package gcexportdata_test
+
+import (
+	"go/token"
+	"go/types"
+	"log"
+	"os"
+	"testing"
+
+	"golang.org/x/tools/go/gcexportdata"
+)
+
+// Test to ensure that gcexportdata can read files produced by App
+// Engine Go runtime v1.6.
+func TestAppEngine16(t *testing.T) {
+	// Open and read the file.
+	f, err := os.Open("testdata/errors-ae16.a")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	r, err := gcexportdata.NewReader(f)
+	if err != nil {
+		log.Fatalf("reading export data: %v", err)
+	}
+
+	// Decode the export data.
+	fset := token.NewFileSet()
+	imports := make(map[string]*types.Package)
+	pkg, err := gcexportdata.Read(r, fset, imports, "errors")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Print package information.
+	got := pkg.Scope().Lookup("New").Type().String()
+	want := "func(text string) error"
+	if got != want {
+		t.Errorf("New.Type = %s, want %s", got, want)
+	}
+}

vendor/golang.org/x/tools/go/gcexportdata/importer.go

@@ -0,0 +1,73 @@
+// Copyright 2016 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 gcexportdata
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"os"
+)
+
+// NewImporter returns a new instance of the types.Importer interface
+// that reads type information from export data files written by gc.
+// The Importer also satisfies types.ImporterFrom.
+//
+// Export data files are located using "go build" workspace conventions
+// and the build.Default context.
+//
+// Use this importer instead of go/importer.For("gc", ...) to avoid the
+// version-skew problems described in the documentation of this package,
+// or to control the FileSet or access the imports map populated during
+// package loading.
+//
+func NewImporter(fset *token.FileSet, imports map[string]*types.Package) types.ImporterFrom {
+	return importer{fset, imports}
+}
+
+type importer struct {
+	fset    *token.FileSet
+	imports map[string]*types.Package
+}
+
+func (imp importer) Import(importPath string) (*types.Package, error) {
+	return imp.ImportFrom(importPath, "", 0)
+}
+
+func (imp importer) ImportFrom(importPath, srcDir string, mode types.ImportMode) (_ *types.Package, err error) {
+	filename, path := Find(importPath, srcDir)
+	if filename == "" {
+		if importPath == "unsafe" {
+			// Even for unsafe, call Find first in case
+			// the package was vendored.
+			return types.Unsafe, nil
+		}
+		return nil, fmt.Errorf("can't find import: %s", importPath)
+	}
+
+	if pkg, ok := imp.imports[path]; ok && pkg.Complete() {
+		return pkg, nil // cache hit
+	}
+
+	// open file
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		f.Close()
+		if err != nil {
+			// add file name to error
+			err = fmt.Errorf("reading export data: %s: %v", filename, err)
+		}
+	}()
+
+	r, err := NewReader(f)
+	if err != nil {
+		return nil, err
+	}
+
+	return Read(r, imp.fset, imp.imports, path)
+}

vendor/golang.org/x/tools/go/gcexportdata/main.go

@@ -0,0 +1,99 @@
+// Copyright 2017 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 ignore
+
+// The gcexportdata command is a diagnostic tool that displays the
+// contents of gc export data files.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/token"
+	"go/types"
+	"log"
+	"os"
+
+	"golang.org/x/tools/go/gcexportdata"
+	"golang.org/x/tools/go/types/typeutil"
+)
+
+var packageFlag = flag.String("package", "", "alternative package to print")
+
+func main() {
+	log.SetPrefix("gcexportdata: ")
+	log.SetFlags(0)
+	flag.Usage = func() {
+		fmt.Fprintln(os.Stderr, "usage: gcexportdata [-package path] file.a")
+	}
+	flag.Parse()
+	if flag.NArg() != 1 {
+		flag.Usage()
+		os.Exit(2)
+	}
+	filename := flag.Args()[0]
+
+	f, err := os.Open(filename)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	r, err := gcexportdata.NewReader(f)
+	if err != nil {
+		log.Fatalf("%s: %s", filename, err)
+	}
+
+	// Decode the package.
+	const primary = "<primary>"
+	imports := make(map[string]*types.Package)
+	fset := token.NewFileSet()
+	pkg, err := gcexportdata.Read(r, fset, imports, primary)
+	if err != nil {
+		log.Fatalf("%s: %s", filename, err)
+	}
+
+	// Optionally select an indirectly mentioned package.
+	if *packageFlag != "" {
+		pkg = imports[*packageFlag]
+		if pkg == nil {
+			fmt.Fprintf(os.Stderr, "export data file %s does not mention %s; has:\n",
+				filename, *packageFlag)
+			for p := range imports {
+				if p != primary {
+					fmt.Fprintf(os.Stderr, "\t%s\n", p)
+				}
+			}
+			os.Exit(1)
+		}
+	}
+
+	// Print all package-level declarations, including non-exported ones.
+	fmt.Printf("package %s\n", pkg.Name())
+	for _, imp := range pkg.Imports() {
+		fmt.Printf("import %q\n", imp.Path())
+	}
+	qual := func(p *types.Package) string {
+		if pkg == p {
+			return ""
+		}
+		return p.Name()
+	}
+	scope := pkg.Scope()
+	for _, name := range scope.Names() {
+		obj := scope.Lookup(name)
+		fmt.Printf("%s: %s\n",
+			fset.Position(obj.Pos()),
+			types.ObjectString(obj, qual))
+
+		// For types, print each method.
+		if _, ok := obj.(*types.TypeName); ok {
+			for _, method := range typeutil.IntuitiveMethodSet(obj.Type(), nil) {
+				fmt.Printf("%s: %s\n",
+					fset.Position(method.Obj().Pos()),
+					types.SelectionString(method, qual))
+			}
+		}
+	}
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/backdoor.go

@@ -0,0 +1,28 @@
+package gccgoimporter
+
+// This file opens a back door to the parser for golang.org/x/tools/go/gccgoexportdata.
+
+import (
+	"go/types"
+	"io"
+)
+
+// Parse reads and parses gccgo export data from in and constructs a
+// Package, inserting it into the imports map.
+func Parse(in io.Reader, imports map[string]*types.Package, path string) (_ *types.Package, err error) {
+	var p parser
+	p.init(path, in, imports)
+	defer func() {
+		switch x := recover().(type) {
+		case nil:
+			// success
+		case importError:
+			err = x
+		default:
+			panic(x) // resume unexpected panic
+		}
+	}()
+	pkg := p.parsePackage()
+	imports[path] = pkg
+	return pkg, err
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/gccgoinstallation.go

@@ -0,0 +1,99 @@
+// 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.
+
+package gccgoimporter
+
+// This is a verbatim copy of $GOROOT/src/go/internal/gccgoimporter/gccgoinstallation.go.
+
+import (
+	"bufio"
+	"go/types"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// Information about a specific installation of gccgo.
+type GccgoInstallation struct {
+	// Version of gcc (e.g. 4.8.0).
+	GccVersion string
+
+	// Target triple (e.g. x86_64-unknown-linux-gnu).
+	TargetTriple string
+
+	// Built-in library paths used by this installation.
+	LibPaths []string
+}
+
+// Ask the driver at the given path for information for this GccgoInstallation.
+// The given arguments are passed directly to the call to the driver.
+func (inst *GccgoInstallation) InitFromDriver(gccgoPath string, args ...string) (err error) {
+	argv := append([]string{"-###", "-S", "-x", "go", "-"}, args...)
+	cmd := exec.Command(gccgoPath, argv...)
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return
+	}
+
+	err = cmd.Start()
+	if err != nil {
+		return
+	}
+
+	scanner := bufio.NewScanner(stderr)
+	for scanner.Scan() {
+		line := scanner.Text()
+		switch {
+		case strings.HasPrefix(line, "Target: "):
+			inst.TargetTriple = line[8:]
+
+		case line[0] == ' ':
+			args := strings.Fields(line)
+			for _, arg := range args[1:] {
+				if strings.HasPrefix(arg, "-L") {
+					inst.LibPaths = append(inst.LibPaths, arg[2:])
+				}
+			}
+		}
+	}
+
+	argv = append([]string{"-dumpversion"}, args...)
+	stdout, err := exec.Command(gccgoPath, argv...).Output()
+	if err != nil {
+		return
+	}
+	inst.GccVersion = strings.TrimSpace(string(stdout))
+
+	return
+}
+
+// Return the list of export search paths for this GccgoInstallation.
+func (inst *GccgoInstallation) SearchPaths() (paths []string) {
+	for _, lpath := range inst.LibPaths {
+		spath := filepath.Join(lpath, "go", inst.GccVersion)
+		fi, err := os.Stat(spath)
+		if err != nil || !fi.IsDir() {
+			continue
+		}
+		paths = append(paths, spath)
+
+		spath = filepath.Join(spath, inst.TargetTriple)
+		fi, err = os.Stat(spath)
+		if err != nil || !fi.IsDir() {
+			continue
+		}
+		paths = append(paths, spath)
+	}
+
+	paths = append(paths, inst.LibPaths...)
+
+	return
+}
+
+// Return an importer that searches incpaths followed by the gcc installation's
+// built-in search paths and the current directory.
+func (inst *GccgoInstallation) GetImporter(incpaths []string, initmap map[*types.Package]InitData) Importer {
+	return GetImporter(append(append(incpaths, inst.SearchPaths()...), "."), initmap)
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/gccgoinstallation_test.go

@@ -0,0 +1,191 @@
+// 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.
+
+package gccgoimporter
+
+// This is a verbatim copy of $GOROOT/src/go/internal/gccgoimporter/gccgoinstallation_test.go.
+
+import (
+	"go/types"
+	"runtime"
+	"testing"
+)
+
+var importablePackages = [...]string{
+	"archive/tar",
+	"archive/zip",
+	"bufio",
+	"bytes",
+	"compress/bzip2",
+	"compress/flate",
+	"compress/gzip",
+	"compress/lzw",
+	"compress/zlib",
+	"container/heap",
+	"container/list",
+	"container/ring",
+	"crypto/aes",
+	"crypto/cipher",
+	"crypto/des",
+	"crypto/dsa",
+	"crypto/ecdsa",
+	"crypto/elliptic",
+	"crypto",
+	"crypto/hmac",
+	"crypto/md5",
+	"crypto/rand",
+	"crypto/rc4",
+	"crypto/rsa",
+	"crypto/sha1",
+	"crypto/sha256",
+	"crypto/sha512",
+	"crypto/subtle",
+	"crypto/tls",
+	"crypto/x509",
+	"crypto/x509/pkix",
+	"database/sql/driver",
+	"database/sql",
+	"debug/dwarf",
+	"debug/elf",
+	"debug/gosym",
+	"debug/macho",
+	"debug/pe",
+	"encoding/ascii85",
+	"encoding/asn1",
+	"encoding/base32",
+	"encoding/base64",
+	"encoding/binary",
+	"encoding/csv",
+	"encoding/gob",
+	"encoding",
+	"encoding/hex",
+	"encoding/json",
+	"encoding/pem",
+	"encoding/xml",
+	"errors",
+	"expvar",
+	"flag",
+	"fmt",
+	"go/ast",
+	"go/build",
+	"go/doc",
+	"go/format",
+	"go/parser",
+	"go/printer",
+	"go/scanner",
+	"go/token",
+	"hash/adler32",
+	"hash/crc32",
+	"hash/crc64",
+	"hash/fnv",
+	"hash",
+	"html",
+	"html/template",
+	"image/color",
+	"image/color/palette",
+	"image/draw",
+	"image/gif",
+	"image",
+	"image/jpeg",
+	"image/png",
+	"index/suffixarray",
+	"io",
+	"io/ioutil",
+	"log",
+	"log/syslog",
+	"math/big",
+	"math/cmplx",
+	"math",
+	"math/rand",
+	"mime",
+	"mime/multipart",
+	"net",
+	"net/http/cgi",
+	"net/http/cookiejar",
+	"net/http/fcgi",
+	"net/http",
+	"net/http/httptest",
+	"net/http/httputil",
+	"net/http/pprof",
+	"net/mail",
+	"net/rpc",
+	"net/rpc/jsonrpc",
+	"net/smtp",
+	"net/textproto",
+	"net/url",
+	"os/exec",
+	"os",
+	"os/signal",
+	"os/user",
+	"path/filepath",
+	"path",
+	"reflect",
+	"regexp",
+	"regexp/syntax",
+	"runtime/debug",
+	"runtime",
+	"runtime/pprof",
+	"sort",
+	"strconv",
+	"strings",
+	"sync/atomic",
+	"sync",
+	"syscall",
+	"testing",
+	"testing/iotest",
+	"testing/quick",
+	"text/scanner",
+	"text/tabwriter",
+	"text/template",
+	"text/template/parse",
+	"time",
+	"unicode",
+	"unicode/utf16",
+	"unicode/utf8",
+}
+
+func TestInstallationImporter(t *testing.T) {
+	// This test relies on gccgo being around, which it most likely will be if we
+	// were compiled with gccgo.
+	if runtime.Compiler != "gccgo" {
+		t.Skip("This test needs gccgo")
+		return
+	}
+
+	var inst GccgoInstallation
+	err := inst.InitFromDriver("gccgo")
+	if err != nil {
+		t.Fatal(err)
+	}
+	imp := inst.GetImporter(nil, nil)
+
+	// Ensure we don't regress the number of packages we can parse. First import
+	// all packages into the same map and then each individually.
+	pkgMap := make(map[string]*types.Package)
+	for _, pkg := range importablePackages {
+		_, err = imp(pkgMap, pkg)
+		if err != nil {
+			t.Error(err)
+		}
+	}
+
+	for _, pkg := range importablePackages {
+		_, err = imp(make(map[string]*types.Package), pkg)
+		if err != nil {
+			t.Error(err)
+		}
+	}
+
+	// Test for certain specific entities in the imported data.
+	for _, test := range [...]importerTest{
+		{pkgpath: "io", name: "Reader", want: "type Reader interface{Read(p []byte) (n int, err error)}"},
+		{pkgpath: "io", name: "ReadWriter", want: "type ReadWriter interface{Reader; Writer}"},
+		{pkgpath: "math", name: "Pi", want: "const Pi untyped float"},
+		{pkgpath: "math", name: "Sin", want: "func Sin(x float64) float64"},
+		{pkgpath: "sort", name: "Ints", want: "func Ints(a []int)"},
+		{pkgpath: "unsafe", name: "Pointer", want: "type Pointer"},
+	} {
+		runImporterTest(t, imp, nil, &test)
+	}
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/importer.go

@@ -0,0 +1,209 @@
+// 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.
+
+// Package gccgoimporter implements Import for gccgo-generated object files.
+package gccgoimporter // import "golang.org/x/tools/go/internal/gccgoimporter"
+
+// This is a verbatim copy of $GOROOT/src/go/internal/gccgoimporter/importer.go.
+
+import (
+	"bytes"
+	"debug/elf"
+	"fmt"
+	"go/types"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// A PackageInit describes an imported package that needs initialization.
+type PackageInit struct {
+	Name     string // short package name
+	InitFunc string // name of init function
+	Priority int    // priority of init function, see InitData.Priority
+}
+
+// The gccgo-specific init data for a package.
+type InitData struct {
+	// Initialization priority of this package relative to other packages.
+	// This is based on the maximum depth of the package's dependency graph;
+	// it is guaranteed to be greater than that of its dependencies.
+	Priority int
+
+	// The list of packages which this package depends on to be initialized,
+	// including itself if needed. This is the subset of the transitive closure of
+	// the package's dependencies that need initialization.
+	Inits []PackageInit
+}
+
+// Locate the file from which to read export data.
+// This is intended to replicate the logic in gofrontend.
+func findExportFile(searchpaths []string, pkgpath string) (string, error) {
+	for _, spath := range searchpaths {
+		pkgfullpath := filepath.Join(spath, pkgpath)
+		pkgdir, name := filepath.Split(pkgfullpath)
+
+		for _, filepath := range [...]string{
+			pkgfullpath,
+			pkgfullpath + ".gox",
+			pkgdir + "lib" + name + ".so",
+			pkgdir + "lib" + name + ".a",
+			pkgfullpath + ".o",
+		} {
+			fi, err := os.Stat(filepath)
+			if err == nil && !fi.IsDir() {
+				return filepath, nil
+			}
+		}
+	}
+
+	return "", fmt.Errorf("%s: could not find export data (tried %s)", pkgpath, strings.Join(searchpaths, ":"))
+}
+
+const (
+	gccgov1Magic    = "v1;\n"
+	gccgov2Magic    = "v2;\n"
+	goimporterMagic = "\n$$ "
+	archiveMagic    = "!<ar"
+)
+
+// Opens the export data file at the given path. If this is an ELF file,
+// searches for and opens the .go_export section. If this is an archive,
+// reads the export data from the first member, which is assumed to be an ELF file.
+// This is intended to replicate the logic in gofrontend.
+func openExportFile(fpath string) (reader io.ReadSeeker, closer io.Closer, err error) {
+	f, err := os.Open(fpath)
+	if err != nil {
+		return
+	}
+	closer = f
+	defer func() {
+		if err != nil && closer != nil {
+			f.Close()
+		}
+	}()
+
+	var magic [4]byte
+	_, err = f.ReadAt(magic[:], 0)
+	if err != nil {
+		return
+	}
+
+	var elfreader io.ReaderAt
+	switch string(magic[:]) {
+	case gccgov1Magic, gccgov2Magic, goimporterMagic:
+		// Raw export data.
+		reader = f
+		return
+
+	case archiveMagic:
+		// TODO(pcc): Read the archive directly instead of using "ar".
+		f.Close()
+		closer = nil
+
+		cmd := exec.Command("ar", "p", fpath)
+		var out []byte
+		out, err = cmd.Output()
+		if err != nil {
+			return
+		}
+
+		elfreader = bytes.NewReader(out)
+
+	default:
+		elfreader = f
+	}
+
+	ef, err := elf.NewFile(elfreader)
+	if err != nil {
+		return
+	}
+
+	sec := ef.Section(".go_export")
+	if sec == nil {
+		err = fmt.Errorf("%s: .go_export section not found", fpath)
+		return
+	}
+
+	reader = sec.Open()
+	return
+}
+
+// An Importer resolves import paths to Packages. The imports map records
+// packages already known, indexed by package path.
+// An importer must determine the canonical package path and check imports
+// to see if it is already present in the map. If so, the Importer can return
+// the map entry. Otherwise, the importer must load the package data for the
+// given path into a new *Package, record it in imports map, and return the
+// package.
+type Importer func(imports map[string]*types.Package, path string) (*types.Package, error)
+
+func GetImporter(searchpaths []string, initmap map[*types.Package]InitData) Importer {
+	return func(imports map[string]*types.Package, pkgpath string) (pkg *types.Package, err error) {
+		if pkgpath == "unsafe" {
+			return types.Unsafe, nil
+		}
+
+		fpath, err := findExportFile(searchpaths, pkgpath)
+		if err != nil {
+			return
+		}
+
+		reader, closer, err := openExportFile(fpath)
+		if err != nil {
+			return
+		}
+		if closer != nil {
+			defer closer.Close()
+		}
+
+		var magic [4]byte
+		_, err = reader.Read(magic[:])
+		if err != nil {
+			return
+		}
+		_, err = reader.Seek(0, 0) // 0 bytes after start (use 0, io.SeekStart when we drop Go 1.6)
+		if err != nil {
+			return
+		}
+
+		switch string(magic[:]) {
+		case gccgov1Magic, gccgov2Magic:
+			var p parser
+			p.init(fpath, reader, imports)
+			pkg = p.parsePackage()
+			if initmap != nil {
+				initmap[pkg] = p.initdata
+			}
+
+		// Excluded for now: Standard gccgo doesn't support this import format currently.
+		// case goimporterMagic:
+		// 	var data []byte
+		// 	data, err = ioutil.ReadAll(reader)
+		// 	if err != nil {
+		// 		return
+		// 	}
+		// 	var n int
+		// 	n, pkg, err = importer.ImportData(imports, data)
+		// 	if err != nil {
+		// 		return
+		// 	}
+
+		// 	if initmap != nil {
+		// 		suffixreader := bytes.NewReader(data[n:])
+		// 		var p parser
+		// 		p.init(fpath, suffixreader, nil)
+		// 		p.parseInitData()
+		// 		initmap[pkg] = p.initdata
+		// 	}
+
+		default:
+			err = fmt.Errorf("unrecognized magic string: %q", string(magic[:]))
+		}
+
+		return
+	}
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/importer19_test.go

@@ -0,0 +1,15 @@
+// Copyright 2017 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 go1.9
+
+package gccgoimporter
+
+var aliasTests = []importerTest{
+	{pkgpath: "alias", name: "IntAlias2", want: "type IntAlias2 = Int"},
+}
+
+func init() {
+	importerTests = append(importerTests, aliasTests...)
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/importer_test.go

@@ -0,0 +1,190 @@
+// 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.
+
+package gccgoimporter
+
+// This is a verbatim copy of $GOROOT/src/go/internal/gccgoimporter/importer_test.go
+// except for the importerTests variable which does not contain Go1.9-specific tests.
+// Those are added via importer19_test.go.
+
+import (
+	"go/types"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+type importerTest struct {
+	pkgpath, name, want, wantval string
+	wantinits                    []string
+}
+
+func runImporterTest(t *testing.T, imp Importer, initmap map[*types.Package]InitData, test *importerTest) {
+	pkg, err := imp(make(map[string]*types.Package), test.pkgpath)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if test.name != "" {
+		obj := pkg.Scope().Lookup(test.name)
+		if obj == nil {
+			t.Errorf("%s: object not found", test.name)
+			return
+		}
+
+		got := types.ObjectString(obj, types.RelativeTo(pkg))
+		if got != test.want {
+			t.Errorf("%s: got %q; want %q", test.name, got, test.want)
+		}
+
+		if test.wantval != "" {
+			gotval := obj.(*types.Const).Val().String()
+			if gotval != test.wantval {
+				t.Errorf("%s: got val %q; want val %q", test.name, gotval, test.wantval)
+			}
+		}
+	}
+
+	if len(test.wantinits) > 0 {
+		initdata := initmap[pkg]
+		found := false
+		// Check that the package's own init function has the package's priority
+		for _, pkginit := range initdata.Inits {
+			if pkginit.InitFunc == test.wantinits[0] {
+				if initdata.Priority != pkginit.Priority {
+					t.Errorf("%s: got self priority %d; want %d", test.pkgpath, pkginit.Priority, initdata.Priority)
+				}
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			t.Errorf("%s: could not find expected function %q", test.pkgpath, test.wantinits[0])
+		}
+
+		// Each init function in the list other than the first one is a
+		// dependency of the function immediately before it. Check that
+		// the init functions appear in descending priority order.
+		priority := initdata.Priority
+		for _, wantdepinit := range test.wantinits[1:] {
+			found = false
+			for _, pkginit := range initdata.Inits {
+				if pkginit.InitFunc == wantdepinit {
+					if priority <= pkginit.Priority {
+						t.Errorf("%s: got dep priority %d; want less than %d", test.pkgpath, pkginit.Priority, priority)
+					}
+					found = true
+					priority = pkginit.Priority
+					break
+				}
+			}
+
+			if !found {
+				t.Errorf("%s: could not find expected function %q", test.pkgpath, wantdepinit)
+			}
+		}
+	}
+}
+
+var importerTests = []importerTest{
+	{pkgpath: "pointer", name: "Int8Ptr", want: "type Int8Ptr *int8"},
+	{pkgpath: "complexnums", name: "NN", want: "const NN untyped complex", wantval: "(-1 + -1i)"},
+	{pkgpath: "complexnums", name: "NP", want: "const NP untyped complex", wantval: "(-1 + 1i)"},
+	{pkgpath: "complexnums", name: "PN", want: "const PN untyped complex", wantval: "(1 + -1i)"},
+	{pkgpath: "complexnums", name: "PP", want: "const PP untyped complex", wantval: "(1 + 1i)"},
+	{pkgpath: "conversions", name: "Bits", want: "const Bits Units", wantval: `"bits"`},
+	{pkgpath: "time", name: "Duration", want: "type Duration int64"},
+	{pkgpath: "time", name: "Nanosecond", want: "const Nanosecond Duration", wantval: "1"},
+	{pkgpath: "unicode", name: "IsUpper", want: "func IsUpper(r rune) bool"},
+	{pkgpath: "unicode", name: "MaxRune", want: "const MaxRune untyped rune", wantval: "1114111"},
+	{pkgpath: "imports", wantinits: []string{"imports..import", "fmt..import", "math..import"}},
+	{pkgpath: "escapeinfo", name: "NewT", want: "func NewT(data []byte) *T"},
+}
+
+func TestGoxImporter(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
+
+	initmap := make(map[*types.Package]InitData)
+	imp := GetImporter([]string{"testdata"}, initmap)
+
+	for _, test := range importerTests {
+		runImporterTest(t, imp, initmap, &test)
+	}
+}
+
+func TestObjImporter(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
+
+	// This test relies on gccgo being around, which it most likely will be if we
+	// were compiled with gccgo.
+	if runtime.Compiler != "gccgo" {
+		t.Skip("This test needs gccgo")
+		return
+	}
+
+	tmpdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	initmap := make(map[*types.Package]InitData)
+	imp := GetImporter([]string{tmpdir}, initmap)
+
+	artmpdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	arinitmap := make(map[*types.Package]InitData)
+	arimp := GetImporter([]string{artmpdir}, arinitmap)
+
+	for _, test := range importerTests {
+		gofile := filepath.Join("testdata", test.pkgpath+".go")
+
+		if _, err := os.Stat(gofile); err != nil {
+			// There is a .gox file but no .go file,
+			// so there is nothing to compile.
+			continue
+		}
+
+		ofile := filepath.Join(tmpdir, test.pkgpath+".o")
+		afile := filepath.Join(artmpdir, "lib"+test.pkgpath+".a")
+
+		cmd := exec.Command("gccgo", "-fgo-pkgpath="+test.pkgpath, "-c", "-o", ofile, gofile)
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			t.Logf("%s", out)
+			t.Fatalf("gccgo %s failed: %s", gofile, err)
+		}
+
+		// The expected initializations are version dependent,
+		// so don't check for them.
+		test.wantinits = nil
+
+		runImporterTest(t, imp, initmap, &test)
+
+		cmd = exec.Command("ar", "cr", afile, ofile)
+		out, err = cmd.CombinedOutput()
+		if err != nil {
+			t.Logf("%s", out)
+			t.Fatalf("ar cr %s %s failed: %s", afile, ofile, err)
+		}
+
+		runImporterTest(t, arimp, arinitmap, &test)
+
+		if err = os.Remove(ofile); err != nil {
+			t.Fatal(err)
+		}
+		if err = os.Remove(afile); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	if err = os.Remove(tmpdir); err != nil {
+		t.Fatal(err)
+	}
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/newInterface10.go

@@ -0,0 +1,21 @@
+// Copyright 2018 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 !go1.11
+
+package gccgoimporter
+
+import "go/types"
+
+func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
+	named := make([]*types.Named, len(embeddeds))
+	for i, e := range embeddeds {
+		var ok bool
+		named[i], ok = e.(*types.Named)
+		if !ok {
+			panic("embedding of non-defined interfaces in interfaces is not supported before Go 1.11")
+		}
+	}
+	return types.NewInterface(methods, named)
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/newInterface11.go

@@ -0,0 +1,13 @@
+// Copyright 2018 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 go1.11
+
+package gccgoimporter
+
+import "go/types"
+
+func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
+	return types.NewInterfaceType(methods, embeddeds)
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/parser.go

@@ -0,0 +1,910 @@
+// 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.
+
+package gccgoimporter
+
+// This is a verbatim copy of $GOROOT/src/go/internal/gccgoimporter/parser.go.
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"io"
+	"strconv"
+	"strings"
+	"text/scanner"
+)
+
+type parser struct {
+	scanner  scanner.Scanner
+	version  string                    // format version
+	tok      rune                      // current token
+	lit      string                    // literal string; only valid for Ident, Int, String tokens
+	pkgpath  string                    // package path of imported package
+	pkgname  string                    // name of imported package
+	pkg      *types.Package            // reference to imported package
+	imports  map[string]*types.Package // package path -> package object
+	typeMap  map[int]types.Type        // type number -> type
+	initdata InitData                  // package init priority data
+}
+
+func (p *parser) init(filename string, src io.Reader, imports map[string]*types.Package) {
+	p.scanner.Init(src)
+	p.scanner.Error = func(_ *scanner.Scanner, msg string) { p.error(msg) }
+	p.scanner.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanFloats | scanner.ScanStrings | scanner.ScanComments | scanner.SkipComments
+	p.scanner.Whitespace = 1<<'\t' | 1<<'\n' | 1<<' '
+	p.scanner.Filename = filename // for good error messages
+	p.next()
+	p.imports = imports
+	p.typeMap = make(map[int]types.Type)
+}
+
+type importError struct {
+	pos scanner.Position
+	err error
+}
+
+func (e importError) Error() string {
+	return fmt.Sprintf("import error %s (byte offset = %d): %s", e.pos, e.pos.Offset, e.err)
+}
+
+func (p *parser) error(err interface{}) {
+	if s, ok := err.(string); ok {
+		err = errors.New(s)
+	}
+	// panic with a runtime.Error if err is not an error
+	panic(importError{p.scanner.Pos(), err.(error)})
+}
+
+func (p *parser) errorf(format string, args ...interface{}) {
+	p.error(fmt.Errorf(format, args...))
+}
+
+func (p *parser) expect(tok rune) string {
+	lit := p.lit
+	if p.tok != tok {
+		p.errorf("expected %s, got %s (%s)", scanner.TokenString(tok), scanner.TokenString(p.tok), lit)
+	}
+	p.next()
+	return lit
+}
+
+func (p *parser) expectKeyword(keyword string) {
+	lit := p.expect(scanner.Ident)
+	if lit != keyword {
+		p.errorf("expected keyword %s, got %q", keyword, lit)
+	}
+}
+
+func (p *parser) parseString() string {
+	str, err := strconv.Unquote(p.expect(scanner.String))
+	if err != nil {
+		p.error(err)
+	}
+	return str
+}
+
+// unquotedString     = { unquotedStringChar } .
+// unquotedStringChar = <neither a whitespace nor a ';' char> .
+func (p *parser) parseUnquotedString() string {
+	if p.tok == scanner.EOF {
+		p.error("unexpected EOF")
+	}
+	var buf bytes.Buffer
+	buf.WriteString(p.scanner.TokenText())
+	// This loop needs to examine each character before deciding whether to consume it. If we see a semicolon,
+	// we need to let it be consumed by p.next().
+	for ch := p.scanner.Peek(); ch != ';' && ch != scanner.EOF && p.scanner.Whitespace&(1<<uint(ch)) == 0; ch = p.scanner.Peek() {
+		buf.WriteRune(ch)
+		p.scanner.Next()
+	}
+	p.next()
+	return buf.String()
+}
+
+func (p *parser) next() {
+	p.tok = p.scanner.Scan()
+	switch p.tok {
+	case scanner.Ident, scanner.Int, scanner.Float, scanner.String, '·':
+		p.lit = p.scanner.TokenText()
+	default:
+		p.lit = ""
+	}
+}
+
+func (p *parser) parseQualifiedName() (path, name string) {
+	return p.parseQualifiedNameStr(p.parseString())
+}
+
+func (p *parser) parseUnquotedQualifiedName() (path, name string) {
+	return p.parseQualifiedNameStr(p.parseUnquotedString())
+}
+
+// qualifiedName = [ ["."] unquotedString "." ] unquotedString .
+//
+// The above production uses greedy matching.
+func (p *parser) parseQualifiedNameStr(unquotedName string) (pkgpath, name string) {
+	parts := strings.Split(unquotedName, ".")
+	if parts[0] == "" {
+		parts = parts[1:]
+	}
+
+	switch len(parts) {
+	case 0:
+		p.errorf("malformed qualified name: %q", unquotedName)
+	case 1:
+		// unqualified name
+		pkgpath = p.pkgpath
+		name = parts[0]
+	default:
+		// qualified name, which may contain periods
+		pkgpath = strings.Join(parts[0:len(parts)-1], ".")
+		name = parts[len(parts)-1]
+	}
+
+	return
+}
+
+// getPkg returns the package for a given path. If the package is
+// not found but we have a package name, create the package and
+// add it to the p.imports map.
+//
+func (p *parser) getPkg(pkgpath, name string) *types.Package {
+	// package unsafe is not in the imports map - handle explicitly
+	if pkgpath == "unsafe" {
+		return types.Unsafe
+	}
+	pkg := p.imports[pkgpath]
+	if pkg == nil && name != "" {
+		pkg = types.NewPackage(pkgpath, name)
+		p.imports[pkgpath] = pkg
+	}
+	return pkg
+}
+
+// parseExportedName is like parseQualifiedName, but
+// the package path is resolved to an imported *types.Package.
+//
+// ExportedName = string [string] .
+func (p *parser) parseExportedName() (pkg *types.Package, name string) {
+	path, name := p.parseQualifiedName()
+	var pkgname string
+	if p.tok == scanner.String {
+		pkgname = p.parseString()
+	}
+	pkg = p.getPkg(path, pkgname)
+	if pkg == nil {
+		p.errorf("package %s (path = %q) not found", name, path)
+	}
+	return
+}
+
+// Name = QualifiedName | "?" .
+func (p *parser) parseName() string {
+	if p.tok == '?' {
+		// Anonymous.
+		p.next()
+		return ""
+	}
+	// The package path is redundant for us. Don't try to parse it.
+	_, name := p.parseUnquotedQualifiedName()
+	return name
+}
+
+func deref(typ types.Type) types.Type {
+	if p, _ := typ.(*types.Pointer); p != nil {
+		typ = p.Elem()
+	}
+	return typ
+}
+
+// Field = Name Type [string] .
+func (p *parser) parseField(pkg *types.Package) (field *types.Var, tag string) {
+	name := p.parseName()
+	typ := p.parseType(pkg)
+	anon := false
+	if name == "" {
+		anon = true
+		switch typ := deref(typ).(type) {
+		case *types.Basic:
+			name = typ.Name()
+		case *types.Named:
+			name = typ.Obj().Name()
+		default:
+			p.error("anonymous field expected")
+		}
+	}
+	field = types.NewField(token.NoPos, pkg, name, typ, anon)
+	if p.tok == scanner.String {
+		tag = p.parseString()
+	}
+	return
+}
+
+// Param = Name ["..."] Type .
+func (p *parser) parseParam(pkg *types.Package) (param *types.Var, isVariadic bool) {
+	name := p.parseName()
+	if p.tok == '<' && p.scanner.Peek() == 'e' {
+		// EscInfo = "<esc:" int ">" . (optional and ignored)
+		p.next()
+		p.expectKeyword("esc")
+		p.expect(':')
+		p.expect(scanner.Int)
+		p.expect('>')
+	}
+	if p.tok == '.' {
+		p.next()
+		p.expect('.')
+		p.expect('.')
+		isVariadic = true
+	}
+	typ := p.parseType(pkg)
+	if isVariadic {
+		typ = types.NewSlice(typ)
+	}
+	param = types.NewParam(token.NoPos, pkg, name, typ)
+	return
+}
+
+// Var = Name Type .
+func (p *parser) parseVar(pkg *types.Package) *types.Var {
+	name := p.parseName()
+	return types.NewVar(token.NoPos, pkg, name, p.parseType(pkg))
+}
+
+// Conversion = "convert" "(" Type "," ConstValue ")" .
+func (p *parser) parseConversion(pkg *types.Package) (val constant.Value, typ types.Type) {
+	p.expectKeyword("convert")
+	p.expect('(')
+	typ = p.parseType(pkg)
+	p.expect(',')
+	val, _ = p.parseConstValue(pkg)
+	p.expect(')')
+	return
+}
+
+// ConstValue     = string | "false" | "true" | ["-"] (int ["'"] | FloatOrComplex) | Conversion .
+// FloatOrComplex = float ["i" | ("+"|"-") float "i"] .
+func (p *parser) parseConstValue(pkg *types.Package) (val constant.Value, typ types.Type) {
+	switch p.tok {
+	case scanner.String:
+		str := p.parseString()
+		val = constant.MakeString(str)
+		typ = types.Typ[types.UntypedString]
+		return
+
+	case scanner.Ident:
+		b := false
+		switch p.lit {
+		case "false":
+		case "true":
+			b = true
+
+		case "convert":
+			return p.parseConversion(pkg)
+
+		default:
+			p.errorf("expected const value, got %s (%q)", scanner.TokenString(p.tok), p.lit)
+		}
+
+		p.next()
+		val = constant.MakeBool(b)
+		typ = types.Typ[types.UntypedBool]
+		return
+	}
+
+	sign := ""
+	if p.tok == '-' {
+		p.next()
+		sign = "-"
+	}
+
+	switch p.tok {
+	case scanner.Int:
+		val = constant.MakeFromLiteral(sign+p.lit, token.INT, 0)
+		if val == nil {
+			p.error("could not parse integer literal")
+		}
+
+		p.next()
+		if p.tok == '\'' {
+			p.next()
+			typ = types.Typ[types.UntypedRune]
+		} else {
+			typ = types.Typ[types.UntypedInt]
+		}
+
+	case scanner.Float:
+		re := sign + p.lit
+		p.next()
+
+		var im string
+		switch p.tok {
+		case '+':
+			p.next()
+			im = p.expect(scanner.Float)
+
+		case '-':
+			p.next()
+			im = "-" + p.expect(scanner.Float)
+
+		case scanner.Ident:
+			// re is in fact the imaginary component. Expect "i" below.
+			im = re
+			re = "0"
+
+		default:
+			val = constant.MakeFromLiteral(re, token.FLOAT, 0)
+			if val == nil {
+				p.error("could not parse float literal")
+			}
+			typ = types.Typ[types.UntypedFloat]
+			return
+		}
+
+		p.expectKeyword("i")
+		reval := constant.MakeFromLiteral(re, token.FLOAT, 0)
+		if reval == nil {
+			p.error("could not parse real component of complex literal")
+		}
+		imval := constant.MakeFromLiteral(im+"i", token.IMAG, 0)
+		if imval == nil {
+			p.error("could not parse imag component of complex literal")
+		}
+		val = constant.BinaryOp(reval, token.ADD, imval)
+		typ = types.Typ[types.UntypedComplex]
+
+	default:
+		p.errorf("expected const value, got %s (%q)", scanner.TokenString(p.tok), p.lit)
+	}
+
+	return
+}
+
+// Const = Name [Type] "=" ConstValue .
+func (p *parser) parseConst(pkg *types.Package) *types.Const {
+	name := p.parseName()
+	var typ types.Type
+	if p.tok == '<' {
+		typ = p.parseType(pkg)
+	}
+	p.expect('=')
+	val, vtyp := p.parseConstValue(pkg)
+	if typ == nil {
+		typ = vtyp
+	}
+	return types.NewConst(token.NoPos, pkg, name, typ, val)
+}
+
+// NamedType = TypeName [ "=" ] Type { Method } .
+// TypeName  = ExportedName .
+// Method    = "func" "(" Param ")" Name ParamList ResultList ";" .
+func (p *parser) parseNamedType(n int) types.Type {
+	pkg, name := p.parseExportedName()
+	scope := pkg.Scope()
+
+	if p.tok == '=' {
+		// type alias
+		p.next()
+		typ := p.parseType(pkg)
+		if obj := scope.Lookup(name); obj != nil {
+			typ = obj.Type() // use previously imported type
+			if typ == nil {
+				p.errorf("%v (type alias) used in cycle", obj)
+			}
+		} else {
+			obj = types.NewTypeName(token.NoPos, pkg, name, typ)
+			scope.Insert(obj)
+		}
+		p.typeMap[n] = typ
+		return typ
+	}
+
+	// named type
+	obj := scope.Lookup(name)
+	if obj == nil {
+		// a named type may be referred to before the underlying type
+		// is known - set it up
+		tname := types.NewTypeName(token.NoPos, pkg, name, nil)
+		types.NewNamed(tname, nil, nil)
+		scope.Insert(tname)
+		obj = tname
+	}
+
+	typ := obj.Type()
+	p.typeMap[n] = typ
+
+	nt, ok := typ.(*types.Named)
+	if !ok {
+		// This can happen for unsafe.Pointer, which is a TypeName holding a Basic type.
+		pt := p.parseType(pkg)
+		if pt != typ {
+			p.error("unexpected underlying type for non-named TypeName")
+		}
+		return typ
+	}
+
+	underlying := p.parseType(pkg)
+	if nt.Underlying() == nil {
+		nt.SetUnderlying(underlying.Underlying())
+	}
+
+	// collect associated methods
+	for p.tok == scanner.Ident {
+		p.expectKeyword("func")
+		p.expect('(')
+		receiver, _ := p.parseParam(pkg)
+		p.expect(')')
+		name := p.parseName()
+		params, isVariadic := p.parseParamList(pkg)
+		results := p.parseResultList(pkg)
+		p.expect(';')
+
+		sig := types.NewSignature(receiver, params, results, isVariadic)
+		nt.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig))
+	}
+
+	return nt
+}
+
+func (p *parser) parseInt() int64 {
+	lit := p.expect(scanner.Int)
+	n, err := strconv.ParseInt(lit, 10, 0)
+	if err != nil {
+		p.error(err)
+	}
+	return n
+}
+
+// ArrayOrSliceType = "[" [ int ] "]" Type .
+func (p *parser) parseArrayOrSliceType(pkg *types.Package) types.Type {
+	p.expect('[')
+	if p.tok == ']' {
+		p.next()
+		return types.NewSlice(p.parseType(pkg))
+	}
+
+	n := p.parseInt()
+	p.expect(']')
+	return types.NewArray(p.parseType(pkg), n)
+}
+
+// MapType = "map" "[" Type "]" Type .
+func (p *parser) parseMapType(pkg *types.Package) types.Type {
+	p.expectKeyword("map")
+	p.expect('[')
+	key := p.parseType(pkg)
+	p.expect(']')
+	elem := p.parseType(pkg)
+	return types.NewMap(key, elem)
+}
+
+// ChanType = "chan" ["<-" | "-<"] Type .
+func (p *parser) parseChanType(pkg *types.Package) types.Type {
+	p.expectKeyword("chan")
+	dir := types.SendRecv
+	switch p.tok {
+	case '-':
+		p.next()
+		p.expect('<')
+		dir = types.SendOnly
+
+	case '<':
+		// don't consume '<' if it belongs to Type
+		if p.scanner.Peek() == '-' {
+			p.next()
+			p.expect('-')
+			dir = types.RecvOnly
+		}
+	}
+
+	return types.NewChan(dir, p.parseType(pkg))
+}
+
+// StructType = "struct" "{" { Field } "}" .
+func (p *parser) parseStructType(pkg *types.Package) types.Type {
+	p.expectKeyword("struct")
+
+	var fields []*types.Var
+	var tags []string
+
+	p.expect('{')
+	for p.tok != '}' && p.tok != scanner.EOF {
+		field, tag := p.parseField(pkg)
+		p.expect(';')
+		fields = append(fields, field)
+		tags = append(tags, tag)
+	}
+	p.expect('}')
+
+	return types.NewStruct(fields, tags)
+}
+
+// ParamList = "(" [ { Parameter "," } Parameter ] ")" .
+func (p *parser) parseParamList(pkg *types.Package) (*types.Tuple, bool) {
+	var list []*types.Var
+	isVariadic := false
+
+	p.expect('(')
+	for p.tok != ')' && p.tok != scanner.EOF {
+		if len(list) > 0 {
+			p.expect(',')
+		}
+		par, variadic := p.parseParam(pkg)
+		list = append(list, par)
+		if variadic {
+			if isVariadic {
+				p.error("... not on final argument")
+			}
+			isVariadic = true
+		}
+	}
+	p.expect(')')
+
+	return types.NewTuple(list...), isVariadic
+}
+
+// ResultList = Type | ParamList .
+func (p *parser) parseResultList(pkg *types.Package) *types.Tuple {
+	switch p.tok {
+	case '<':
+		return types.NewTuple(types.NewParam(token.NoPos, pkg, "", p.parseType(pkg)))
+
+	case '(':
+		params, _ := p.parseParamList(pkg)
+		return params
+
+	default:
+		return nil
+	}
+}
+
+// FunctionType = ParamList ResultList .
+func (p *parser) parseFunctionType(pkg *types.Package) *types.Signature {
+	params, isVariadic := p.parseParamList(pkg)
+	results := p.parseResultList(pkg)
+	return types.NewSignature(nil, params, results, isVariadic)
+}
+
+// Func = Name FunctionType .
+func (p *parser) parseFunc(pkg *types.Package) *types.Func {
+	name := p.parseName()
+	if strings.ContainsRune(name, '$') {
+		// This is a Type$equal or Type$hash function, which we don't want to parse,
+		// except for the types.
+		p.discardDirectiveWhileParsingTypes(pkg)
+		return nil
+	}
+	return types.NewFunc(token.NoPos, pkg, name, p.parseFunctionType(pkg))
+}
+
+// InterfaceType = "interface" "{" { ("?" Type | Func) ";" } "}" .
+func (p *parser) parseInterfaceType(pkg *types.Package) types.Type {
+	p.expectKeyword("interface")
+
+	var methods []*types.Func
+	var embeddeds []types.Type
+
+	p.expect('{')
+	for p.tok != '}' && p.tok != scanner.EOF {
+		if p.tok == '?' {
+			p.next()
+			embeddeds = append(embeddeds, p.parseType(pkg))
+		} else {
+			method := p.parseFunc(pkg)
+			methods = append(methods, method)
+		}
+		p.expect(';')
+	}
+	p.expect('}')
+
+	return newInterface(methods, embeddeds)
+}
+
+// PointerType = "*" ("any" | Type) .
+func (p *parser) parsePointerType(pkg *types.Package) types.Type {
+	p.expect('*')
+	if p.tok == scanner.Ident {
+		p.expectKeyword("any")
+		return types.Typ[types.UnsafePointer]
+	}
+	return types.NewPointer(p.parseType(pkg))
+}
+
+// TypeDefinition = NamedType | MapType | ChanType | StructType | InterfaceType | PointerType | ArrayOrSliceType | FunctionType .
+func (p *parser) parseTypeDefinition(pkg *types.Package, n int) types.Type {
+	var t types.Type
+	switch p.tok {
+	case scanner.String:
+		t = p.parseNamedType(n)
+
+	case scanner.Ident:
+		switch p.lit {
+		case "map":
+			t = p.parseMapType(pkg)
+
+		case "chan":
+			t = p.parseChanType(pkg)
+
+		case "struct":
+			t = p.parseStructType(pkg)
+
+		case "interface":
+			t = p.parseInterfaceType(pkg)
+		}
+
+	case '*':
+		t = p.parsePointerType(pkg)
+
+	case '[':
+		t = p.parseArrayOrSliceType(pkg)
+
+	case '(':
+		t = p.parseFunctionType(pkg)
+	}
+
+	p.typeMap[n] = t
+	return t
+}
+
+const (
+	// From gofrontend/go/export.h
+	// Note that these values are negative in the gofrontend and have been made positive
+	// in the gccgoimporter.
+	gccgoBuiltinINT8       = 1
+	gccgoBuiltinINT16      = 2
+	gccgoBuiltinINT32      = 3
+	gccgoBuiltinINT64      = 4
+	gccgoBuiltinUINT8      = 5
+	gccgoBuiltinUINT16     = 6
+	gccgoBuiltinUINT32     = 7
+	gccgoBuiltinUINT64     = 8
+	gccgoBuiltinFLOAT32    = 9
+	gccgoBuiltinFLOAT64    = 10
+	gccgoBuiltinINT        = 11
+	gccgoBuiltinUINT       = 12
+	gccgoBuiltinUINTPTR    = 13
+	gccgoBuiltinBOOL       = 15
+	gccgoBuiltinSTRING     = 16
+	gccgoBuiltinCOMPLEX64  = 17
+	gccgoBuiltinCOMPLEX128 = 18
+	gccgoBuiltinERROR      = 19
+	gccgoBuiltinBYTE       = 20
+	gccgoBuiltinRUNE       = 21
+)
+
+func lookupBuiltinType(typ int) types.Type {
+	return [...]types.Type{
+		gccgoBuiltinINT8:       types.Typ[types.Int8],
+		gccgoBuiltinINT16:      types.Typ[types.Int16],
+		gccgoBuiltinINT32:      types.Typ[types.Int32],
+		gccgoBuiltinINT64:      types.Typ[types.Int64],
+		gccgoBuiltinUINT8:      types.Typ[types.Uint8],
+		gccgoBuiltinUINT16:     types.Typ[types.Uint16],
+		gccgoBuiltinUINT32:     types.Typ[types.Uint32],
+		gccgoBuiltinUINT64:     types.Typ[types.Uint64],
+		gccgoBuiltinFLOAT32:    types.Typ[types.Float32],
+		gccgoBuiltinFLOAT64:    types.Typ[types.Float64],
+		gccgoBuiltinINT:        types.Typ[types.Int],
+		gccgoBuiltinUINT:       types.Typ[types.Uint],
+		gccgoBuiltinUINTPTR:    types.Typ[types.Uintptr],
+		gccgoBuiltinBOOL:       types.Typ[types.Bool],
+		gccgoBuiltinSTRING:     types.Typ[types.String],
+		gccgoBuiltinCOMPLEX64:  types.Typ[types.Complex64],
+		gccgoBuiltinCOMPLEX128: types.Typ[types.Complex128],
+		gccgoBuiltinERROR:      types.Universe.Lookup("error").Type(),
+		gccgoBuiltinBYTE:       types.Universe.Lookup("byte").Type(),
+		gccgoBuiltinRUNE:       types.Universe.Lookup("rune").Type(),
+	}[typ]
+}
+
+// Type = "<" "type" ( "-" int | int [ TypeDefinition ] ) ">" .
+func (p *parser) parseType(pkg *types.Package) (t types.Type) {
+	p.expect('<')
+	p.expectKeyword("type")
+
+	switch p.tok {
+	case scanner.Int:
+		n := p.parseInt()
+
+		if p.tok == '>' {
+			t = p.typeMap[int(n)]
+		} else {
+			t = p.parseTypeDefinition(pkg, int(n))
+		}
+
+	case '-':
+		p.next()
+		n := p.parseInt()
+		t = lookupBuiltinType(int(n))
+
+	default:
+		p.errorf("expected type number, got %s (%q)", scanner.TokenString(p.tok), p.lit)
+		return nil
+	}
+
+	p.expect('>')
+	return
+}
+
+// PackageInit = unquotedString unquotedString int .
+func (p *parser) parsePackageInit() PackageInit {
+	name := p.parseUnquotedString()
+	initfunc := p.parseUnquotedString()
+	priority := -1
+	if p.version == "v1" {
+		priority = int(p.parseInt())
+	}
+	return PackageInit{Name: name, InitFunc: initfunc, Priority: priority}
+}
+
+// Throw away tokens until we see a ';'. If we see a '<', attempt to parse as a type.
+func (p *parser) discardDirectiveWhileParsingTypes(pkg *types.Package) {
+	for {
+		switch p.tok {
+		case ';':
+			return
+		case '<':
+			p.parseType(pkg)
+		case scanner.EOF:
+			p.error("unexpected EOF")
+		default:
+			p.next()
+		}
+	}
+}
+
+// Create the package if we have parsed both the package path and package name.
+func (p *parser) maybeCreatePackage() {
+	if p.pkgname != "" && p.pkgpath != "" {
+		p.pkg = p.getPkg(p.pkgpath, p.pkgname)
+	}
+}
+
+// InitDataDirective = ( "v1" | "v2" ) ";" |
+//                     "priority" int ";" |
+//                     "init" { PackageInit } ";" |
+//                     "checksum" unquotedString ";" .
+func (p *parser) parseInitDataDirective() {
+	if p.tok != scanner.Ident {
+		// unexpected token kind; panic
+		p.expect(scanner.Ident)
+	}
+
+	switch p.lit {
+	case "v1", "v2":
+		p.version = p.lit
+		p.next()
+		p.expect(';')
+
+	case "priority":
+		p.next()
+		p.initdata.Priority = int(p.parseInt())
+		p.expect(';')
+
+	case "init":
+		p.next()
+		for p.tok != ';' && p.tok != scanner.EOF {
+			p.initdata.Inits = append(p.initdata.Inits, p.parsePackageInit())
+		}
+		p.expect(';')
+
+	case "init_graph":
+		p.next()
+		// The graph data is thrown away for now.
+		for p.tok != ';' && p.tok != scanner.EOF {
+			p.parseInt()
+			p.parseInt()
+		}
+		p.expect(';')
+
+	case "checksum":
+		// Don't let the scanner try to parse the checksum as a number.
+		defer func(mode uint) {
+			p.scanner.Mode = mode
+		}(p.scanner.Mode)
+		p.scanner.Mode &^= scanner.ScanInts | scanner.ScanFloats
+		p.next()
+		p.parseUnquotedString()
+		p.expect(';')
+
+	default:
+		p.errorf("unexpected identifier: %q", p.lit)
+	}
+}
+
+// Directive = InitDataDirective |
+//             "package" unquotedString [ unquotedString ] [ unquotedString ] ";" |
+//             "pkgpath" unquotedString ";" |
+//             "prefix" unquotedString ";" |
+//             "import" unquotedString unquotedString string ";" |
+//             "func" Func ";" |
+//             "type" Type ";" |
+//             "var" Var ";" |
+//             "const" Const ";" .
+func (p *parser) parseDirective() {
+	if p.tok != scanner.Ident {
+		// unexpected token kind; panic
+		p.expect(scanner.Ident)
+	}
+
+	switch p.lit {
+	case "v1", "v2", "priority", "init", "init_graph", "checksum":
+		p.parseInitDataDirective()
+
+	case "package":
+		p.next()
+		p.pkgname = p.parseUnquotedString()
+		p.maybeCreatePackage()
+		if p.version == "v2" && p.tok != ';' {
+			p.parseUnquotedString()
+			p.parseUnquotedString()
+		}
+		p.expect(';')
+
+	case "pkgpath":
+		p.next()
+		p.pkgpath = p.parseUnquotedString()
+		p.maybeCreatePackage()
+		p.expect(';')
+
+	case "prefix":
+		p.next()
+		p.pkgpath = p.parseUnquotedString()
+		p.expect(';')
+
+	case "import":
+		p.next()
+		pkgname := p.parseUnquotedString()
+		pkgpath := p.parseUnquotedString()
+		p.getPkg(pkgpath, pkgname)
+		p.parseString()
+		p.expect(';')
+
+	case "func":
+		p.next()
+		fun := p.parseFunc(p.pkg)
+		if fun != nil {
+			p.pkg.Scope().Insert(fun)
+		}
+		p.expect(';')
+
+	case "type":
+		p.next()
+		p.parseType(p.pkg)
+		p.expect(';')
+
+	case "var":
+		p.next()
+		v := p.parseVar(p.pkg)
+		p.pkg.Scope().Insert(v)
+		p.expect(';')
+
+	case "const":
+		p.next()
+		c := p.parseConst(p.pkg)
+		p.pkg.Scope().Insert(c)
+		p.expect(';')
+
+	default:
+		p.errorf("unexpected identifier: %q", p.lit)
+	}
+}
+
+// Package = { Directive } .
+func (p *parser) parsePackage() *types.Package {
+	for p.tok != scanner.EOF {
+		p.parseDirective()
+	}
+	for _, typ := range p.typeMap {
+		if it, ok := typ.(*types.Interface); ok {
+			it.Complete()
+		}
+	}
+	p.pkg.MarkComplete()
+	return p.pkg
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/parser_test.go

@@ -0,0 +1,79 @@
+// 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.
+
+package gccgoimporter
+
+// This is a verbatim copy of $GOROOT/src/go/internal/gccgoimporter/parser_test.go.
+
+import (
+	"bytes"
+	"go/types"
+	"strings"
+	"testing"
+	"text/scanner"
+)
+
+var typeParserTests = []struct {
+	id, typ, want, underlying, methods string
+}{
+	{id: "foo", typ: "<type -1>", want: "int8"},
+	{id: "foo", typ: "<type 1 *<type -19>>", want: "*error"},
+	{id: "foo", typ: "<type 1 *any>", want: "unsafe.Pointer"},
+	{id: "foo", typ: "<type 1 \"Bar\" <type 2 *<type 1>>>", want: "foo.Bar", underlying: "*foo.Bar"},
+	{id: "foo", typ: "<type 1 \"bar.Foo\" \"bar\" <type -1> func (? <type 1>) M (); >", want: "bar.Foo", underlying: "int8", methods: "func (bar.Foo).M()"},
+	{id: "foo", typ: "<type 1 \".bar.foo\" \"bar\" <type -1>>", want: "bar.foo", underlying: "int8"},
+	{id: "foo", typ: "<type 1 []<type -1>>", want: "[]int8"},
+	{id: "foo", typ: "<type 1 [42]<type -1>>", want: "[42]int8"},
+	{id: "foo", typ: "<type 1 map [<type -1>] <type -2>>", want: "map[int8]int16"},
+	{id: "foo", typ: "<type 1 chan <type -1>>", want: "chan int8"},
+	{id: "foo", typ: "<type 1 chan <- <type -1>>", want: "<-chan int8"},
+	{id: "foo", typ: "<type 1 chan -< <type -1>>", want: "chan<- int8"},
+	{id: "foo", typ: "<type 1 struct { I8 <type -1>; I16 <type -2> \"i16\"; }>", want: "struct{I8 int8; I16 int16 \"i16\"}"},
+	{id: "foo", typ: "<type 1 interface { Foo (a <type -1>, b <type -2>) <type -1>; Bar (? <type -2>, ? ...<type -1>) (? <type -2>, ? <type -1>); Baz (); }>", want: "interface{Bar(int16, ...int8) (int16, int8); Baz(); Foo(a int8, b int16) int8}"},
+	{id: "foo", typ: "<type 1 (? <type -1>) <type -2>>", want: "func(int8) int16"},
+}
+
+func TestTypeParser(t *testing.T) {
+	for _, test := range typeParserTests {
+		var p parser
+		p.init("test.gox", strings.NewReader(test.typ), make(map[string]*types.Package))
+		p.pkgname = test.id
+		p.pkgpath = test.id
+		p.maybeCreatePackage()
+		typ := p.parseType(p.pkg)
+
+		if p.tok != scanner.EOF {
+			t.Errorf("expected full parse, stopped at %q", p.lit)
+		}
+
+		// interfaces must be explicitly completed
+		if ityp, _ := typ.(*types.Interface); ityp != nil {
+			ityp.Complete()
+		}
+
+		got := typ.String()
+		if got != test.want {
+			t.Errorf("got type %q, expected %q", got, test.want)
+		}
+
+		if test.underlying != "" {
+			underlying := typ.Underlying().String()
+			if underlying != test.underlying {
+				t.Errorf("got underlying type %q, expected %q", underlying, test.underlying)
+			}
+		}
+
+		if test.methods != "" {
+			nt := typ.(*types.Named)
+			var buf bytes.Buffer
+			for i := 0; i != nt.NumMethods(); i++ {
+				buf.WriteString(nt.Method(i).String())
+			}
+			methods := buf.String()
+			if methods != test.methods {
+				t.Errorf("got methods %q, expected %q", methods, test.methods)
+			}
+		}
+	}
+}

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/alias.gox

@@ -0,0 +1,4 @@
+v1;
+package alias;
+pkgpath alias;
+type <type 115 "I1" <type 116 interface { M1 (? <type 117 "IntAlias2" = <type 118 "IntAlias" = <type 119 "Int" <type -11>>>>) < type 114>; M2 () <type 1>; }>>;

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/complexnums.go

@@ -0,0 +1,6 @@
+package complexnums
+
+const NN = -1 - 1i
+const NP = -1 + 1i
+const PN = 1 - 1i
+const PP = 1 + 1i

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/complexnums.gox

@@ -0,0 +1,8 @@
+v1;
+package complexnums;
+pkgpath complexnums;
+priority 1;
+const NN = -0.1E1-0.1E1i ;
+const NP = -0.1E1+0.1E1i ;
+const PN = 0.1E1-0.1E1i ;
+const PP = 0.1E1+0.1E1i ;

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/conversions.go

@@ -0,0 +1,5 @@
+package conversions
+
+type Units string
+
+const Bits = Units("bits")

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/conversions.gox

@@ -0,0 +1,6 @@
+v2;
+package conversions;
+prefix go;
+package conversions go.conversions go.conversions;
+const Bits <type 1 "Units" <type -16>> = convert(<type 1>, "bits");
+type <type 1>;

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/escapeinfo.go

@@ -0,0 +1,13 @@
+// Test case for escape info in export data. To compile and extract .gox file:
+// gccgo -fgo-optimize-allocs -c escapeinfo.go
+// objcopy -j .go_export escapeinfo.o escapeinfo.gox
+
+package escapeinfo
+
+type T struct{ data []byte }
+
+func NewT(data []byte) *T {
+	return &T{data}
+}
+
+func (*T) Read(p []byte) {}

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/imports.go

@@ -0,0 +1,5 @@
+package imports
+
+import "fmt"
+
+var Hello = fmt.Sprintf("Hello, world")

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/imports.gox

@@ -0,0 +1,7 @@
+v1;
+package imports;
+pkgpath imports;
+priority 7;
+import fmt fmt "fmt";
+init imports imports..import 7 math math..import 1 runtime runtime..import 1 strconv strconv..import 2 io io..import 3 reflect reflect..import 3 syscall syscall..import 3 time time..import 4 os os..import 5 fmt fmt..import 6;
+var Hello <type -16>;

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/pointer.go

@@ -0,0 +1,3 @@
+package pointer
+
+type Int8Ptr *int8

vendor/golang.org/x/tools/go/internal/gccgoimporter/testdata/pointer.gox

@@ -0,0 +1,4 @@
+v1;
+package pointer;
+pkgpath pointer;
+type <type 1 "Int8Ptr" <type 2 *<type -1>>>;

vendor/golang.org/x/tools/go/internal/gccgoimporter/testenv_test.go

@@ -0,0 +1,40 @@
+package gccgoimporter
+
+// This file contains testing utilities copied from $GOROOT/src/internal/testenv/testenv.go.
+
+import (
+	"runtime"
+	"strings"
+	"testing"
+)
+
+// HasGoBuild reports whether the current system can build programs with ``go build''
+// and then run them with os.StartProcess or exec.Command.
+func HasGoBuild() bool {
+	switch runtime.GOOS {
+	case "android", "nacl":
+		return false
+	case "darwin":
+		if strings.HasPrefix(runtime.GOARCH, "arm") {
+			return false
+		}
+	}
+	return true
+}
+
+// MustHaveGoBuild checks that the current system can build programs with ``go build''
+// and then run them with os.StartProcess or exec.Command.
+// If not, MustHaveGoBuild calls t.Skip with an explanation.
+func MustHaveGoBuild(t *testing.T) {
+	if !HasGoBuild() {
+		t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+var testenv = struct {
+	HasGoBuild      func() bool
+	MustHaveGoBuild func(*testing.T)
+}{
+	HasGoBuild:      HasGoBuild,
+	MustHaveGoBuild: MustHaveGoBuild,
+}

vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go

@@ -0,0 +1,852 @@
+// Copyright 2016 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.
+
+// Binary package export.
+// This file was derived from $GOROOT/src/cmd/compile/internal/gc/bexport.go;
+// see that file for specification of the format.
+
+package gcimporter
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"math"
+	"math/big"
+	"sort"
+	"strings"
+)
+
+// If debugFormat is set, each integer and string value is preceded by a marker
+// and position information in the encoding. This mechanism permits an importer
+// to recognize immediately when it is out of sync. The importer recognizes this
+// mode automatically (i.e., it can import export data produced with debugging
+// support even if debugFormat is not set at the time of import). This mode will
+// lead to massively larger export data (by a factor of 2 to 3) and should only
+// be enabled during development and debugging.
+//
+// NOTE: This flag is the first flag to enable if importing dies because of
+// (suspected) format errors, and whenever a change is made to the format.
+const debugFormat = false // default: false
+
+// If trace is set, debugging output is printed to std out.
+const trace = false // default: false
+
+// Current export format version. Increase with each format change.
+// Note: The latest binary (non-indexed) export format is at version 6.
+//       This exporter is still at level 4, but it doesn't matter since
+//       the binary importer can handle older versions just fine.
+// 6: package height (CL 105038) -- NOT IMPLEMENTED HERE
+// 5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMEMTED HERE
+// 4: type name objects support type aliases, uses aliasTag
+// 3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
+// 2: removed unused bool in ODCL export (compiler only)
+// 1: header format change (more regular), export package for _ struct fields
+// 0: Go1.7 encoding
+const exportVersion = 4
+
+// trackAllTypes enables cycle tracking for all types, not just named
+// types. The existing compiler invariants assume that unnamed types
+// that are not completely set up are not used, or else there are spurious
+// errors.
+// If disabled, only named types are tracked, possibly leading to slightly
+// less efficient encoding in rare cases. It also prevents the export of
+// some corner-case type declarations (but those are not handled correctly
+// with with the textual export format either).
+// TODO(gri) enable and remove once issues caused by it are fixed
+const trackAllTypes = false
+
+type exporter struct {
+	fset *token.FileSet
+	out  bytes.Buffer
+
+	// object -> index maps, indexed in order of serialization
+	strIndex map[string]int
+	pkgIndex map[*types.Package]int
+	typIndex map[types.Type]int
+
+	// position encoding
+	posInfoFormat bool
+	prevFile      string
+	prevLine      int
+
+	// debugging support
+	written int // bytes written
+	indent  int // for trace
+}
+
+// internalError represents an error generated inside this package.
+type internalError string
+
+func (e internalError) Error() string { return "gcimporter: " + string(e) }
+
+func internalErrorf(format string, args ...interface{}) error {
+	return internalError(fmt.Sprintf(format, args...))
+}
+
+// BExportData returns binary export data for pkg.
+// If no file set is provided, position info will be missing.
+func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			if ierr, ok := e.(internalError); ok {
+				err = ierr
+				return
+			}
+			// Not an internal error; panic again.
+			panic(e)
+		}
+	}()
+
+	p := exporter{
+		fset:          fset,
+		strIndex:      map[string]int{"": 0}, // empty string is mapped to 0
+		pkgIndex:      make(map[*types.Package]int),
+		typIndex:      make(map[types.Type]int),
+		posInfoFormat: true, // TODO(gri) might become a flag, eventually
+	}
+
+	// write version info
+	// The version string must start with "version %d" where %d is the version
+	// number. Additional debugging information may follow after a blank; that
+	// text is ignored by the importer.
+	p.rawStringln(fmt.Sprintf("version %d", exportVersion))
+	var debug string
+	if debugFormat {
+		debug = "debug"
+	}
+	p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
+	p.bool(trackAllTypes)
+	p.bool(p.posInfoFormat)
+
+	// --- generic export data ---
+
+	// populate type map with predeclared "known" types
+	for index, typ := range predeclared {
+		p.typIndex[typ] = index
+	}
+	if len(p.typIndex) != len(predeclared) {
+		return nil, internalError("duplicate entries in type map?")
+	}
+
+	// write package data
+	p.pkg(pkg, true)
+	if trace {
+		p.tracef("\n")
+	}
+
+	// write objects
+	objcount := 0
+	scope := pkg.Scope()
+	for _, name := range scope.Names() {
+		if !ast.IsExported(name) {
+			continue
+		}
+		if trace {
+			p.tracef("\n")
+		}
+		p.obj(scope.Lookup(name))
+		objcount++
+	}
+
+	// indicate end of list
+	if trace {
+		p.tracef("\n")
+	}
+	p.tag(endTag)
+
+	// for self-verification only (redundant)
+	p.int(objcount)
+
+	if trace {
+		p.tracef("\n")
+	}
+
+	// --- end of export data ---
+
+	return p.out.Bytes(), nil
+}
+
+func (p *exporter) pkg(pkg *types.Package, emptypath bool) {
+	if pkg == nil {
+		panic(internalError("unexpected nil pkg"))
+	}
+
+	// if we saw the package before, write its index (>= 0)
+	if i, ok := p.pkgIndex[pkg]; ok {
+		p.index('P', i)
+		return
+	}
+
+	// otherwise, remember the package, write the package tag (< 0) and package data
+	if trace {
+		p.tracef("P%d = { ", len(p.pkgIndex))
+		defer p.tracef("} ")
+	}
+	p.pkgIndex[pkg] = len(p.pkgIndex)
+
+	p.tag(packageTag)
+	p.string(pkg.Name())
+	if emptypath {
+		p.string("")
+	} else {
+		p.string(pkg.Path())
+	}
+}
+
+func (p *exporter) obj(obj types.Object) {
+	switch obj := obj.(type) {
+	case *types.Const:
+		p.tag(constTag)
+		p.pos(obj)
+		p.qualifiedName(obj)
+		p.typ(obj.Type())
+		p.value(obj.Val())
+
+	case *types.TypeName:
+		if isAlias(obj) {
+			p.tag(aliasTag)
+			p.pos(obj)
+			p.qualifiedName(obj)
+		} else {
+			p.tag(typeTag)
+		}
+		p.typ(obj.Type())
+
+	case *types.Var:
+		p.tag(varTag)
+		p.pos(obj)
+		p.qualifiedName(obj)
+		p.typ(obj.Type())
+
+	case *types.Func:
+		p.tag(funcTag)
+		p.pos(obj)
+		p.qualifiedName(obj)
+		sig := obj.Type().(*types.Signature)
+		p.paramList(sig.Params(), sig.Variadic())
+		p.paramList(sig.Results(), false)
+
+	default:
+		panic(internalErrorf("unexpected object %v (%T)", obj, obj))
+	}
+}
+
+func (p *exporter) pos(obj types.Object) {
+	if !p.posInfoFormat {
+		return
+	}
+
+	file, line := p.fileLine(obj)
+	if file == p.prevFile {
+		// common case: write line delta
+		// delta == 0 means different file or no line change
+		delta := line - p.prevLine
+		p.int(delta)
+		if delta == 0 {
+			p.int(-1) // -1 means no file change
+		}
+	} else {
+		// different file
+		p.int(0)
+		// Encode filename as length of common prefix with previous
+		// filename, followed by (possibly empty) suffix. Filenames
+		// frequently share path prefixes, so this can save a lot
+		// of space and make export data size less dependent on file
+		// path length. The suffix is unlikely to be empty because
+		// file names tend to end in ".go".
+		n := commonPrefixLen(p.prevFile, file)
+		p.int(n)           // n >= 0
+		p.string(file[n:]) // write suffix only
+		p.prevFile = file
+		p.int(line)
+	}
+	p.prevLine = line
+}
+
+func (p *exporter) fileLine(obj types.Object) (file string, line int) {
+	if p.fset != nil {
+		pos := p.fset.Position(obj.Pos())
+		file = pos.Filename
+		line = pos.Line
+	}
+	return
+}
+
+func commonPrefixLen(a, b string) int {
+	if len(a) > len(b) {
+		a, b = b, a
+	}
+	// len(a) <= len(b)
+	i := 0
+	for i < len(a) && a[i] == b[i] {
+		i++
+	}
+	return i
+}
+
+func (p *exporter) qualifiedName(obj types.Object) {
+	p.string(obj.Name())
+	p.pkg(obj.Pkg(), false)
+}
+
+func (p *exporter) typ(t types.Type) {
+	if t == nil {
+		panic(internalError("nil type"))
+	}
+
+	// Possible optimization: Anonymous pointer types *T where
+	// T is a named type are common. We could canonicalize all
+	// such types *T to a single type PT = *T. This would lead
+	// to at most one *T entry in typIndex, and all future *T's
+	// would be encoded as the respective index directly. Would
+	// save 1 byte (pointerTag) per *T and reduce the typIndex
+	// size (at the cost of a canonicalization map). We can do
+	// this later, without encoding format change.
+
+	// if we saw the type before, write its index (>= 0)
+	if i, ok := p.typIndex[t]; ok {
+		p.index('T', i)
+		return
+	}
+
+	// otherwise, remember the type, write the type tag (< 0) and type data
+	if trackAllTypes {
+		if trace {
+			p.tracef("T%d = {>\n", len(p.typIndex))
+			defer p.tracef("<\n} ")
+		}
+		p.typIndex[t] = len(p.typIndex)
+	}
+
+	switch t := t.(type) {
+	case *types.Named:
+		if !trackAllTypes {
+			// if we don't track all types, track named types now
+			p.typIndex[t] = len(p.typIndex)
+		}
+
+		p.tag(namedTag)
+		p.pos(t.Obj())
+		p.qualifiedName(t.Obj())
+		p.typ(t.Underlying())
+		if !types.IsInterface(t) {
+			p.assocMethods(t)
+		}
+
+	case *types.Array:
+		p.tag(arrayTag)
+		p.int64(t.Len())
+		p.typ(t.Elem())
+
+	case *types.Slice:
+		p.tag(sliceTag)
+		p.typ(t.Elem())
+
+	case *dddSlice:
+		p.tag(dddTag)
+		p.typ(t.elem)
+
+	case *types.Struct:
+		p.tag(structTag)
+		p.fieldList(t)
+
+	case *types.Pointer:
+		p.tag(pointerTag)
+		p.typ(t.Elem())
+
+	case *types.Signature:
+		p.tag(signatureTag)
+		p.paramList(t.Params(), t.Variadic())
+		p.paramList(t.Results(), false)
+
+	case *types.Interface:
+		p.tag(interfaceTag)
+		p.iface(t)
+
+	case *types.Map:
+		p.tag(mapTag)
+		p.typ(t.Key())
+		p.typ(t.Elem())
+
+	case *types.Chan:
+		p.tag(chanTag)
+		p.int(int(3 - t.Dir())) // hack
+		p.typ(t.Elem())
+
+	default:
+		panic(internalErrorf("unexpected type %T: %s", t, t))
+	}
+}
+
+func (p *exporter) assocMethods(named *types.Named) {
+	// Sort methods (for determinism).
+	var methods []*types.Func
+	for i := 0; i < named.NumMethods(); i++ {
+		methods = append(methods, named.Method(i))
+	}
+	sort.Sort(methodsByName(methods))
+
+	p.int(len(methods))
+
+	if trace && methods != nil {
+		p.tracef("associated methods {>\n")
+	}
+
+	for i, m := range methods {
+		if trace && i > 0 {
+			p.tracef("\n")
+		}
+
+		p.pos(m)
+		name := m.Name()
+		p.string(name)
+		if !exported(name) {
+			p.pkg(m.Pkg(), false)
+		}
+
+		sig := m.Type().(*types.Signature)
+		p.paramList(types.NewTuple(sig.Recv()), false)
+		p.paramList(sig.Params(), sig.Variadic())
+		p.paramList(sig.Results(), false)
+		p.int(0) // dummy value for go:nointerface pragma - ignored by importer
+	}
+
+	if trace && methods != nil {
+		p.tracef("<\n} ")
+	}
+}
+
+type methodsByName []*types.Func
+
+func (x methodsByName) Len() int           { return len(x) }
+func (x methodsByName) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+func (x methodsByName) Less(i, j int) bool { return x[i].Name() < x[j].Name() }
+
+func (p *exporter) fieldList(t *types.Struct) {
+	if trace && t.NumFields() > 0 {
+		p.tracef("fields {>\n")
+		defer p.tracef("<\n} ")
+	}
+
+	p.int(t.NumFields())
+	for i := 0; i < t.NumFields(); i++ {
+		if trace && i > 0 {
+			p.tracef("\n")
+		}
+		p.field(t.Field(i))
+		p.string(t.Tag(i))
+	}
+}
+
+func (p *exporter) field(f *types.Var) {
+	if !f.IsField() {
+		panic(internalError("field expected"))
+	}
+
+	p.pos(f)
+	p.fieldName(f)
+	p.typ(f.Type())
+}
+
+func (p *exporter) iface(t *types.Interface) {
+	// TODO(gri): enable importer to load embedded interfaces,
+	// then emit Embeddeds and ExplicitMethods separately here.
+	p.int(0)
+
+	n := t.NumMethods()
+	if trace && n > 0 {
+		p.tracef("methods {>\n")
+		defer p.tracef("<\n} ")
+	}
+	p.int(n)
+	for i := 0; i < n; i++ {
+		if trace && i > 0 {
+			p.tracef("\n")
+		}
+		p.method(t.Method(i))
+	}
+}
+
+func (p *exporter) method(m *types.Func) {
+	sig := m.Type().(*types.Signature)
+	if sig.Recv() == nil {
+		panic(internalError("method expected"))
+	}
+
+	p.pos(m)
+	p.string(m.Name())
+	if m.Name() != "_" && !ast.IsExported(m.Name()) {
+		p.pkg(m.Pkg(), false)
+	}
+
+	// interface method; no need to encode receiver.
+	p.paramList(sig.Params(), sig.Variadic())
+	p.paramList(sig.Results(), false)
+}
+
+func (p *exporter) fieldName(f *types.Var) {
+	name := f.Name()
+
+	if f.Anonymous() {
+		// anonymous field - we distinguish between 3 cases:
+		// 1) field name matches base type name and is exported
+		// 2) field name matches base type name and is not exported
+		// 3) field name doesn't match base type name (alias name)
+		bname := basetypeName(f.Type())
+		if name == bname {
+			if ast.IsExported(name) {
+				name = "" // 1) we don't need to know the field name or package
+			} else {
+				name = "?" // 2) use unexported name "?" to force package export
+			}
+		} else {
+			// 3) indicate alias and export name as is
+			// (this requires an extra "@" but this is a rare case)
+			p.string("@")
+		}
+	}
+
+	p.string(name)
+	if name != "" && !ast.IsExported(name) {
+		p.pkg(f.Pkg(), false)
+	}
+}
+
+func basetypeName(typ types.Type) string {
+	switch typ := deref(typ).(type) {
+	case *types.Basic:
+		return typ.Name()
+	case *types.Named:
+		return typ.Obj().Name()
+	default:
+		return "" // unnamed type
+	}
+}
+
+func (p *exporter) paramList(params *types.Tuple, variadic bool) {
+	// use negative length to indicate unnamed parameters
+	// (look at the first parameter only since either all
+	// names are present or all are absent)
+	n := params.Len()
+	if n > 0 && params.At(0).Name() == "" {
+		n = -n
+	}
+	p.int(n)
+	for i := 0; i < params.Len(); i++ {
+		q := params.At(i)
+		t := q.Type()
+		if variadic && i == params.Len()-1 {
+			t = &dddSlice{t.(*types.Slice).Elem()}
+		}
+		p.typ(t)
+		if n > 0 {
+			name := q.Name()
+			p.string(name)
+			if name != "_" {
+				p.pkg(q.Pkg(), false)
+			}
+		}
+		p.string("") // no compiler-specific info
+	}
+}
+
+func (p *exporter) value(x constant.Value) {
+	if trace {
+		p.tracef("= ")
+	}
+
+	switch x.Kind() {
+	case constant.Bool:
+		tag := falseTag
+		if constant.BoolVal(x) {
+			tag = trueTag
+		}
+		p.tag(tag)
+
+	case constant.Int:
+		if v, exact := constant.Int64Val(x); exact {
+			// common case: x fits into an int64 - use compact encoding
+			p.tag(int64Tag)
+			p.int64(v)
+			return
+		}
+		// uncommon case: large x - use float encoding
+		// (powers of 2 will be encoded efficiently with exponent)
+		p.tag(floatTag)
+		p.float(constant.ToFloat(x))
+
+	case constant.Float:
+		p.tag(floatTag)
+		p.float(x)
+
+	case constant.Complex:
+		p.tag(complexTag)
+		p.float(constant.Real(x))
+		p.float(constant.Imag(x))
+
+	case constant.String:
+		p.tag(stringTag)
+		p.string(constant.StringVal(x))
+
+	case constant.Unknown:
+		// package contains type errors
+		p.tag(unknownTag)
+
+	default:
+		panic(internalErrorf("unexpected value %v (%T)", x, x))
+	}
+}
+
+func (p *exporter) float(x constant.Value) {
+	if x.Kind() != constant.Float {
+		panic(internalErrorf("unexpected constant %v, want float", x))
+	}
+	// extract sign (there is no -0)
+	sign := constant.Sign(x)
+	if sign == 0 {
+		// x == 0
+		p.int(0)
+		return
+	}
+	// x != 0
+
+	var f big.Float
+	if v, exact := constant.Float64Val(x); exact {
+		// float64
+		f.SetFloat64(v)
+	} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
+		// TODO(gri): add big.Rat accessor to constant.Value.
+		r := valueToRat(num)
+		f.SetRat(r.Quo(r, valueToRat(denom)))
+	} else {
+		// Value too large to represent as a fraction => inaccessible.
+		// TODO(gri): add big.Float accessor to constant.Value.
+		f.SetFloat64(math.MaxFloat64) // FIXME
+	}
+
+	// extract exponent such that 0.5 <= m < 1.0
+	var m big.Float
+	exp := f.MantExp(&m)
+
+	// extract mantissa as *big.Int
+	// - set exponent large enough so mant satisfies mant.IsInt()
+	// - get *big.Int from mant
+	m.SetMantExp(&m, int(m.MinPrec()))
+	mant, acc := m.Int(nil)
+	if acc != big.Exact {
+		panic(internalError("internal error"))
+	}
+
+	p.int(sign)
+	p.int(exp)
+	p.string(string(mant.Bytes()))
+}
+
+func valueToRat(x constant.Value) *big.Rat {
+	// Convert little-endian to big-endian.
+	// I can't believe this is necessary.
+	bytes := constant.Bytes(x)
+	for i := 0; i < len(bytes)/2; i++ {
+		bytes[i], bytes[len(bytes)-1-i] = bytes[len(bytes)-1-i], bytes[i]
+	}
+	return new(big.Rat).SetInt(new(big.Int).SetBytes(bytes))
+}
+
+func (p *exporter) bool(b bool) bool {
+	if trace {
+		p.tracef("[")
+		defer p.tracef("= %v] ", b)
+	}
+
+	x := 0
+	if b {
+		x = 1
+	}
+	p.int(x)
+	return b
+}
+
+// ----------------------------------------------------------------------------
+// Low-level encoders
+
+func (p *exporter) index(marker byte, index int) {
+	if index < 0 {
+		panic(internalError("invalid index < 0"))
+	}
+	if debugFormat {
+		p.marker('t')
+	}
+	if trace {
+		p.tracef("%c%d ", marker, index)
+	}
+	p.rawInt64(int64(index))
+}
+
+func (p *exporter) tag(tag int) {
+	if tag >= 0 {
+		panic(internalError("invalid tag >= 0"))
+	}
+	if debugFormat {
+		p.marker('t')
+	}
+	if trace {
+		p.tracef("%s ", tagString[-tag])
+	}
+	p.rawInt64(int64(tag))
+}
+
+func (p *exporter) int(x int) {
+	p.int64(int64(x))
+}
+
+func (p *exporter) int64(x int64) {
+	if debugFormat {
+		p.marker('i')
+	}
+	if trace {
+		p.tracef("%d ", x)
+	}
+	p.rawInt64(x)
+}
+
+func (p *exporter) string(s string) {
+	if debugFormat {
+		p.marker('s')
+	}
+	if trace {
+		p.tracef("%q ", s)
+	}
+	// if we saw the string before, write its index (>= 0)
+	// (the empty string is mapped to 0)
+	if i, ok := p.strIndex[s]; ok {
+		p.rawInt64(int64(i))
+		return
+	}
+	// otherwise, remember string and write its negative length and bytes
+	p.strIndex[s] = len(p.strIndex)
+	p.rawInt64(-int64(len(s)))
+	for i := 0; i < len(s); i++ {
+		p.rawByte(s[i])
+	}
+}
+
+// marker emits a marker byte and position information which makes
+// it easy for a reader to detect if it is "out of sync". Used for
+// debugFormat format only.
+func (p *exporter) marker(m byte) {
+	p.rawByte(m)
+	// Enable this for help tracking down the location
+	// of an incorrect marker when running in debugFormat.
+	if false && trace {
+		p.tracef("#%d ", p.written)
+	}
+	p.rawInt64(int64(p.written))
+}
+
+// rawInt64 should only be used by low-level encoders.
+func (p *exporter) rawInt64(x int64) {
+	var tmp [binary.MaxVarintLen64]byte
+	n := binary.PutVarint(tmp[:], x)
+	for i := 0; i < n; i++ {
+		p.rawByte(tmp[i])
+	}
+}
+
+// rawStringln should only be used to emit the initial version string.
+func (p *exporter) rawStringln(s string) {
+	for i := 0; i < len(s); i++ {
+		p.rawByte(s[i])
+	}
+	p.rawByte('\n')
+}
+
+// rawByte is the bottleneck interface to write to p.out.
+// rawByte escapes b as follows (any encoding does that
+// hides '$'):
+//
+//	'$'  => '|' 'S'
+//	'|'  => '|' '|'
+//
+// Necessary so other tools can find the end of the
+// export data by searching for "$$".
+// rawByte should only be used by low-level encoders.
+func (p *exporter) rawByte(b byte) {
+	switch b {
+	case '$':
+		// write '$' as '|' 'S'
+		b = 'S'
+		fallthrough
+	case '|':
+		// write '|' as '|' '|'
+		p.out.WriteByte('|')
+		p.written++
+	}
+	p.out.WriteByte(b)
+	p.written++
+}
+
+// tracef is like fmt.Printf but it rewrites the format string
+// to take care of indentation.
+func (p *exporter) tracef(format string, args ...interface{}) {
+	if strings.ContainsAny(format, "<>\n") {
+		var buf bytes.Buffer
+		for i := 0; i < len(format); i++ {
+			// no need to deal with runes
+			ch := format[i]
+			switch ch {
+			case '>':
+				p.indent++
+				continue
+			case '<':
+				p.indent--
+				continue
+			}
+			buf.WriteByte(ch)
+			if ch == '\n' {
+				for j := p.indent; j > 0; j-- {
+					buf.WriteString(".  ")
+				}
+			}
+		}
+		format = buf.String()
+	}
+	fmt.Printf(format, args...)
+}
+
+// Debugging support.
+// (tagString is only used when tracing is enabled)
+var tagString = [...]string{
+	// Packages
+	-packageTag: "package",
+
+	// Types
+	-namedTag:     "named type",
+	-arrayTag:     "array",
+	-sliceTag:     "slice",
+	-dddTag:       "ddd",
+	-structTag:    "struct",
+	-pointerTag:   "pointer",
+	-signatureTag: "signature",
+	-interfaceTag: "interface",
+	-mapTag:       "map",
+	-chanTag:      "chan",
+
+	// Values
+	-falseTag:    "false",
+	-trueTag:     "true",
+	-int64Tag:    "int64",
+	-floatTag:    "float",
+	-fractionTag: "fraction",
+	-complexTag:  "complex",
+	-stringTag:   "string",
+	-unknownTag:  "unknown",
+
+	// Type aliases
+	-aliasTag: "alias",
+}

vendor/golang.org/x/tools/go/internal/gcimporter/bexport19_test.go

@@ -0,0 +1,96 @@
+// Copyright 2016 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 go1.9
+
+package gcimporter_test
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"testing"
+
+	"golang.org/x/tools/go/internal/gcimporter"
+)
+
+const src = `
+package p
+
+type (
+	T0 = int32
+	T1 = struct{}
+	T2 = struct{ T1 }
+	Invalid = foo // foo is undeclared
+)
+`
+
+func checkPkg(t *testing.T, pkg *types.Package, label string) {
+	T1 := types.NewStruct(nil, nil)
+	T2 := types.NewStruct([]*types.Var{types.NewField(0, pkg, "T1", T1, true)}, nil)
+
+	for _, test := range []struct {
+		name string
+		typ  types.Type
+	}{
+		{"T0", types.Typ[types.Int32]},
+		{"T1", T1},
+		{"T2", T2},
+		{"Invalid", types.Typ[types.Invalid]},
+	} {
+		obj := pkg.Scope().Lookup(test.name)
+		if obj == nil {
+			t.Errorf("%s: %s not found", label, test.name)
+			continue
+		}
+		tname, _ := obj.(*types.TypeName)
+		if tname == nil {
+			t.Errorf("%s: %v not a type name", label, obj)
+			continue
+		}
+		if !tname.IsAlias() {
+			t.Errorf("%s: %v: not marked as alias", label, tname)
+			continue
+		}
+		if got := tname.Type(); !types.Identical(got, test.typ) {
+			t.Errorf("%s: %v: got %v; want %v", label, tname, got, test.typ)
+		}
+	}
+}
+
+func TestTypeAliases(t *testing.T) {
+	// parse and typecheck
+	fset1 := token.NewFileSet()
+	f, err := parser.ParseFile(fset1, "p.go", src, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var conf types.Config
+	pkg1, err := conf.Check("p", fset1, []*ast.File{f}, nil)
+	if err == nil {
+		// foo in undeclared in src; we should see an error
+		t.Fatal("invalid source type-checked without error")
+	}
+	if pkg1 == nil {
+		// despite incorrect src we should see a (partially) type-checked package
+		t.Fatal("nil package returned")
+	}
+	checkPkg(t, pkg1, "export")
+
+	// export
+	exportdata, err := gcimporter.BExportData(fset1, pkg1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// import
+	imports := make(map[string]*types.Package)
+	fset2 := token.NewFileSet()
+	_, pkg2, err := gcimporter.BImportData(fset2, imports, exportdata, pkg1.Path())
+	if err != nil {
+		t.Fatalf("BImportData(%s): %v", pkg1.Path(), err)
+	}
+	checkPkg(t, pkg2, "import")
+}

vendor/golang.org/x/tools/go/internal/gcimporter/bexport_test.go

@@ -0,0 +1,335 @@
+// Copyright 2016 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 gcimporter_test
+
+import (
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/constant"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"reflect"
+	"runtime"
+	"strings"
+	"testing"
+
+	"golang.org/x/tools/go/buildutil"
+	"golang.org/x/tools/go/internal/gcimporter"
+	"golang.org/x/tools/go/loader"
+)
+
+func TestBExportData_stdlib(t *testing.T) {
+	if runtime.Compiler == "gccgo" {
+		t.Skip("gccgo standard library is inaccessible")
+	}
+	if runtime.GOOS == "android" {
+		t.Skipf("incomplete std lib on %s", runtime.GOOS)
+	}
+
+	// Load, parse and type-check the program.
+	ctxt := build.Default // copy
+	ctxt.GOPATH = ""      // disable GOPATH
+	conf := loader.Config{
+		Build:       &ctxt,
+		AllowErrors: true,
+	}
+	for _, path := range buildutil.AllPackages(conf.Build) {
+		conf.Import(path)
+	}
+
+	// Create a package containing type and value errors to ensure
+	// they are properly encoded/decoded.
+	f, err := conf.ParseFile("haserrors/haserrors.go", `package haserrors
+const UnknownValue = "" + 0
+type UnknownType undefined
+`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	conf.CreateFromFiles("haserrors", f)
+
+	prog, err := conf.Load()
+	if err != nil {
+		t.Fatalf("Load failed: %v", err)
+	}
+
+	numPkgs := len(prog.AllPackages)
+	if want := 248; numPkgs < want {
+		t.Errorf("Loaded only %d packages, want at least %d", numPkgs, want)
+	}
+
+	for pkg, info := range prog.AllPackages {
+		if info.Files == nil {
+			continue // empty directory
+		}
+		exportdata, err := gcimporter.BExportData(conf.Fset, pkg)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		imports := make(map[string]*types.Package)
+		fset2 := token.NewFileSet()
+		n, pkg2, err := gcimporter.BImportData(fset2, imports, exportdata, pkg.Path())
+		if err != nil {
+			t.Errorf("BImportData(%s): %v", pkg.Path(), err)
+			continue
+		}
+		if n != len(exportdata) {
+			t.Errorf("BImportData(%s) decoded %d bytes, want %d",
+				pkg.Path(), n, len(exportdata))
+		}
+
+		// Compare the packages' corresponding members.
+		for _, name := range pkg.Scope().Names() {
+			if !ast.IsExported(name) {
+				continue
+			}
+			obj1 := pkg.Scope().Lookup(name)
+			obj2 := pkg2.Scope().Lookup(name)
+			if obj2 == nil {
+				t.Errorf("%s.%s not found, want %s", pkg.Path(), name, obj1)
+				continue
+			}
+
+			fl1 := fileLine(conf.Fset, obj1)
+			fl2 := fileLine(fset2, obj2)
+			if fl1 != fl2 {
+				t.Errorf("%s.%s: got posn %s, want %s",
+					pkg.Path(), name, fl2, fl1)
+			}
+
+			if err := equalObj(obj1, obj2); err != nil {
+				t.Errorf("%s.%s: %s\ngot:  %s\nwant: %s",
+					pkg.Path(), name, err, obj2, obj1)
+			}
+		}
+	}
+}
+
+func fileLine(fset *token.FileSet, obj types.Object) string {
+	posn := fset.Position(obj.Pos())
+	return fmt.Sprintf("%s:%d", posn.Filename, posn.Line)
+}
+
+// equalObj reports how x and y differ.  They are assumed to belong to
+// different universes so cannot be compared directly.
+func equalObj(x, y types.Object) error {
+	if reflect.TypeOf(x) != reflect.TypeOf(y) {
+		return fmt.Errorf("%T vs %T", x, y)
+	}
+	xt := x.Type()
+	yt := y.Type()
+	switch x.(type) {
+	case *types.Var, *types.Func:
+		// ok
+	case *types.Const:
+		xval := x.(*types.Const).Val()
+		yval := y.(*types.Const).Val()
+		// Use string comparison for floating-point values since rounding is permitted.
+		if constant.Compare(xval, token.NEQ, yval) &&
+			!(xval.Kind() == constant.Float && xval.String() == yval.String()) {
+			return fmt.Errorf("unequal constants %s vs %s", xval, yval)
+		}
+	case *types.TypeName:
+		xt = xt.Underlying()
+		yt = yt.Underlying()
+	default:
+		return fmt.Errorf("unexpected %T", x)
+	}
+	return equalType(xt, yt)
+}
+
+func equalType(x, y types.Type) error {
+	if reflect.TypeOf(x) != reflect.TypeOf(y) {
+		return fmt.Errorf("unequal kinds: %T vs %T", x, y)
+	}
+	switch x := x.(type) {
+	case *types.Interface:
+		y := y.(*types.Interface)
+		// TODO(gri): enable separate emission of Embedded interfaces
+		// and ExplicitMethods then use this logic.
+		// if x.NumEmbeddeds() != y.NumEmbeddeds() {
+		// 	return fmt.Errorf("unequal number of embedded interfaces: %d vs %d",
+		// 		x.NumEmbeddeds(), y.NumEmbeddeds())
+		// }
+		// for i := 0; i < x.NumEmbeddeds(); i++ {
+		// 	xi := x.Embedded(i)
+		// 	yi := y.Embedded(i)
+		// 	if xi.String() != yi.String() {
+		// 		return fmt.Errorf("mismatched %th embedded interface: %s vs %s",
+		// 			i, xi, yi)
+		// 	}
+		// }
+		// if x.NumExplicitMethods() != y.NumExplicitMethods() {
+		// 	return fmt.Errorf("unequal methods: %d vs %d",
+		// 		x.NumExplicitMethods(), y.NumExplicitMethods())
+		// }
+		// for i := 0; i < x.NumExplicitMethods(); i++ {
+		// 	xm := x.ExplicitMethod(i)
+		// 	ym := y.ExplicitMethod(i)
+		// 	if xm.Name() != ym.Name() {
+		// 		return fmt.Errorf("mismatched %th method: %s vs %s", i, xm, ym)
+		// 	}
+		// 	if err := equalType(xm.Type(), ym.Type()); err != nil {
+		// 		return fmt.Errorf("mismatched %s method: %s", xm.Name(), err)
+		// 	}
+		// }
+		if x.NumMethods() != y.NumMethods() {
+			return fmt.Errorf("unequal methods: %d vs %d",
+				x.NumMethods(), y.NumMethods())
+		}
+		for i := 0; i < x.NumMethods(); i++ {
+			xm := x.Method(i)
+			ym := y.Method(i)
+			if xm.Name() != ym.Name() {
+				return fmt.Errorf("mismatched %dth method: %s vs %s", i, xm, ym)
+			}
+			if err := equalType(xm.Type(), ym.Type()); err != nil {
+				return fmt.Errorf("mismatched %s method: %s", xm.Name(), err)
+			}
+		}
+	case *types.Array:
+		y := y.(*types.Array)
+		if x.Len() != y.Len() {
+			return fmt.Errorf("unequal array lengths: %d vs %d", x.Len(), y.Len())
+		}
+		if err := equalType(x.Elem(), y.Elem()); err != nil {
+			return fmt.Errorf("array elements: %s", err)
+		}
+	case *types.Basic:
+		y := y.(*types.Basic)
+		if x.Kind() != y.Kind() {
+			return fmt.Errorf("unequal basic types: %s vs %s", x, y)
+		}
+	case *types.Chan:
+		y := y.(*types.Chan)
+		if x.Dir() != y.Dir() {
+			return fmt.Errorf("unequal channel directions: %d vs %d", x.Dir(), y.Dir())
+		}
+		if err := equalType(x.Elem(), y.Elem()); err != nil {
+			return fmt.Errorf("channel elements: %s", err)
+		}
+	case *types.Map:
+		y := y.(*types.Map)
+		if err := equalType(x.Key(), y.Key()); err != nil {
+			return fmt.Errorf("map keys: %s", err)
+		}
+		if err := equalType(x.Elem(), y.Elem()); err != nil {
+			return fmt.Errorf("map values: %s", err)
+		}
+	case *types.Named:
+		y := y.(*types.Named)
+		if x.String() != y.String() {
+			return fmt.Errorf("unequal named types: %s vs %s", x, y)
+		}
+	case *types.Pointer:
+		y := y.(*types.Pointer)
+		if err := equalType(x.Elem(), y.Elem()); err != nil {
+			return fmt.Errorf("pointer elements: %s", err)
+		}
+	case *types.Signature:
+		y := y.(*types.Signature)
+		if err := equalType(x.Params(), y.Params()); err != nil {
+			return fmt.Errorf("parameters: %s", err)
+		}
+		if err := equalType(x.Results(), y.Results()); err != nil {
+			return fmt.Errorf("results: %s", err)
+		}
+		if x.Variadic() != y.Variadic() {
+			return fmt.Errorf("unequal varidicity: %t vs %t",
+				x.Variadic(), y.Variadic())
+		}
+		if (x.Recv() != nil) != (y.Recv() != nil) {
+			return fmt.Errorf("unequal receivers: %s vs %s", x.Recv(), y.Recv())
+		}
+		if x.Recv() != nil {
+			// TODO(adonovan): fix: this assertion fires for interface methods.
+			// The type of the receiver of an interface method is a named type
+			// if the Package was loaded from export data, or an unnamed (interface)
+			// type if the Package was produced by type-checking ASTs.
+			// if err := equalType(x.Recv().Type(), y.Recv().Type()); err != nil {
+			// 	return fmt.Errorf("receiver: %s", err)
+			// }
+		}
+	case *types.Slice:
+		y := y.(*types.Slice)
+		if err := equalType(x.Elem(), y.Elem()); err != nil {
+			return fmt.Errorf("slice elements: %s", err)
+		}
+	case *types.Struct:
+		y := y.(*types.Struct)
+		if x.NumFields() != y.NumFields() {
+			return fmt.Errorf("unequal struct fields: %d vs %d",
+				x.NumFields(), y.NumFields())
+		}
+		for i := 0; i < x.NumFields(); i++ {
+			xf := x.Field(i)
+			yf := y.Field(i)
+			if xf.Name() != yf.Name() {
+				return fmt.Errorf("mismatched fields: %s vs %s", xf, yf)
+			}
+			if err := equalType(xf.Type(), yf.Type()); err != nil {
+				return fmt.Errorf("struct field %s: %s", xf.Name(), err)
+			}
+			if x.Tag(i) != y.Tag(i) {
+				return fmt.Errorf("struct field %s has unequal tags: %q vs %q",
+					xf.Name(), x.Tag(i), y.Tag(i))
+			}
+		}
+	case *types.Tuple:
+		y := y.(*types.Tuple)
+		if x.Len() != y.Len() {
+			return fmt.Errorf("unequal tuple lengths: %d vs %d", x.Len(), y.Len())
+		}
+		for i := 0; i < x.Len(); i++ {
+			if err := equalType(x.At(i).Type(), y.At(i).Type()); err != nil {
+				return fmt.Errorf("tuple element %d: %s", i, err)
+			}
+		}
+	}
+	return nil
+}
+
+// TestVeryLongFile tests the position of an import object declared in
+// a very long input file.  Line numbers greater than maxlines are
+// reported as line 1, not garbage or token.NoPos.
+func TestVeryLongFile(t *testing.T) {
+	// parse and typecheck
+	longFile := "package foo" + strings.Repeat("\n", 123456) + "var X int"
+	fset1 := token.NewFileSet()
+	f, err := parser.ParseFile(fset1, "foo.go", longFile, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var conf types.Config
+	pkg, err := conf.Check("foo", fset1, []*ast.File{f}, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// export
+	exportdata, err := gcimporter.BExportData(fset1, pkg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// import
+	imports := make(map[string]*types.Package)
+	fset2 := token.NewFileSet()
+	_, pkg2, err := gcimporter.BImportData(fset2, imports, exportdata, pkg.Path())
+	if err != nil {
+		t.Fatalf("BImportData(%s): %v", pkg.Path(), err)
+	}
+
+	// compare
+	posn1 := fset1.Position(pkg.Scope().Lookup("X").Pos())
+	posn2 := fset2.Position(pkg2.Scope().Lookup("X").Pos())
+	if want := "foo.go:1:1"; posn2.String() != want {
+		t.Errorf("X position = %s, want %s (orig was %s)",
+			posn2, want, posn1)
+	}
+}

vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go

@@ -0,0 +1,93 @@
+// 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 file is a copy of $GOROOT/src/go/internal/gcimporter/exportdata.go.
+
+// This file implements FindExportData.
+
+package gcimporter
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+)
+
+func readGopackHeader(r *bufio.Reader) (name string, size int, err error) {
+	// See $GOROOT/include/ar.h.
+	hdr := make([]byte, 16+12+6+6+8+10+2)
+	_, err = io.ReadFull(r, hdr)
+	if err != nil {
+		return
+	}
+	// leave for debugging
+	if false {
+		fmt.Printf("header: %s", hdr)
+	}
+	s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
+	size, err = strconv.Atoi(s)
+	if err != nil || hdr[len(hdr)-2] != '`' || hdr[len(hdr)-1] != '\n' {
+		err = fmt.Errorf("invalid archive header")
+		return
+	}
+	name = strings.TrimSpace(string(hdr[:16]))
+	return
+}
+
+// FindExportData positions the reader r at the beginning of the
+// export data section of an underlying GC-created object/archive
+// file by reading from it. The reader must be positioned at the
+// start of the file before calling this function. The hdr result
+// is the string before the export data, either "$$" or "$$B".
+//
+func FindExportData(r *bufio.Reader) (hdr string, err error) {
+	// Read first line to make sure this is an object file.
+	line, err := r.ReadSlice('\n')
+	if err != nil {
+		err = fmt.Errorf("can't find export data (%v)", err)
+		return
+	}
+
+	if string(line) == "!<arch>\n" {
+		// Archive file. Scan to __.PKGDEF.
+		var name string
+		if name, _, err = readGopackHeader(r); err != nil {
+			return
+		}
+
+		// First entry should be __.PKGDEF.
+		if name != "__.PKGDEF" {
+			err = fmt.Errorf("go archive is missing __.PKGDEF")
+			return
+		}
+
+		// Read first line of __.PKGDEF data, so that line
+		// is once again the first line of the input.
+		if line, err = r.ReadSlice('\n'); err != nil {
+			err = fmt.Errorf("can't find export data (%v)", err)
+			return
+		}
+	}
+
+	// Now at __.PKGDEF in archive or still at beginning of file.
+	// Either way, line should begin with "go object ".
+	if !strings.HasPrefix(string(line), "go object ") {
+		err = fmt.Errorf("not a Go object file")
+		return
+	}
+
+	// Skip over object header to export data.
+	// Begins after first line starting with $$.
+	for line[0] != '$' {
+		if line, err = r.ReadSlice('\n'); err != nil {
+			err = fmt.Errorf("can't find export data (%v)", err)
+			return
+		}
+	}
+	hdr = string(line)
+
+	return
+}

vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter11_test.go

@@ -0,0 +1,134 @@
+// Copyright 2018 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 go1.11
+
+package gcimporter
+
+import (
+	"go/types"
+	"os"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+var importedObjectTests = []struct {
+	name string
+	want string
+}{
+	// non-interfaces
+	{"crypto.Hash", "type Hash uint"},
+	{"go/ast.ObjKind", "type ObjKind int"},
+	{"go/types.Qualifier", "type Qualifier func(*Package) string"},
+	{"go/types.Comparable", "func Comparable(T Type) bool"},
+	{"math.Pi", "const Pi untyped float"},
+	{"math.Sin", "func Sin(x float64) float64"},
+	{"go/ast.NotNilFilter", "func NotNilFilter(_ string, v reflect.Value) bool"},
+	{"go/internal/gcimporter.BImportData", "func BImportData(fset *go/token.FileSet, imports map[string]*go/types.Package, data []byte, path string) (_ int, pkg *go/types.Package, err error)"},
+
+	// interfaces
+	{"context.Context", "type Context interface{Deadline() (deadline time.Time, ok bool); Done() <-chan struct{}; Err() error; Value(key interface{}) interface{}}"},
+	{"crypto.Decrypter", "type Decrypter interface{Decrypt(rand io.Reader, msg []byte, opts DecrypterOpts) (plaintext []byte, err error); Public() PublicKey}"},
+	{"encoding.BinaryMarshaler", "type BinaryMarshaler interface{MarshalBinary() (data []byte, err error)}"},
+	{"io.Reader", "type Reader interface{Read(p []byte) (n int, err error)}"},
+	{"io.ReadWriter", "type ReadWriter interface{Reader; Writer}"},
+	{"go/ast.Node", "type Node interface{End() go/token.Pos; Pos() go/token.Pos}"},
+	{"go/types.Type", "type Type interface{String() string; Underlying() Type}"},
+}
+
+func TestImportedTypes(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	for _, test := range importedObjectTests {
+		s := strings.Split(test.name, ".")
+		if len(s) != 2 {
+			t.Fatal("inconsistent test data")
+		}
+		importPath := s[0]
+		objName := s[1]
+
+		pkg, err := Import(make(map[string]*types.Package), importPath, ".")
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		obj := pkg.Scope().Lookup(objName)
+		if obj == nil {
+			t.Errorf("%s: object not found", test.name)
+			continue
+		}
+
+		got := types.ObjectString(obj, types.RelativeTo(pkg))
+		if got != test.want {
+			t.Errorf("%s: got %q; want %q", test.name, got, test.want)
+		}
+
+		if named, _ := obj.Type().(*types.Named); named != nil {
+			verifyInterfaceMethodRecvs(t, named, 0)
+		}
+	}
+}
+
+// verifyInterfaceMethodRecvs verifies that method receiver types
+// are named if the methods belong to a named interface type.
+func verifyInterfaceMethodRecvs(t *testing.T, named *types.Named, level int) {
+	// avoid endless recursion in case of an embedding bug that lead to a cycle
+	if level > 10 {
+		t.Errorf("%s: embeds itself", named)
+		return
+	}
+
+	iface, _ := named.Underlying().(*types.Interface)
+	if iface == nil {
+		return // not an interface
+	}
+
+	// check explicitly declared methods
+	for i := 0; i < iface.NumExplicitMethods(); i++ {
+		m := iface.ExplicitMethod(i)
+		recv := m.Type().(*types.Signature).Recv()
+		if recv == nil {
+			t.Errorf("%s: missing receiver type", m)
+			continue
+		}
+		if recv.Type() != named {
+			t.Errorf("%s: got recv type %s; want %s", m, recv.Type(), named)
+		}
+	}
+
+	// check embedded interfaces (if they are named, too)
+	for i := 0; i < iface.NumEmbeddeds(); i++ {
+		// embedding of interfaces cannot have cycles; recursion will terminate
+		if etype, _ := iface.EmbeddedType(i).(*types.Named); etype != nil {
+			verifyInterfaceMethodRecvs(t, etype, level+1)
+		}
+	}
+}
+func TestIssue25301(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	if f := compile(t, "testdata", "issue25301.go"); f != "" {
+		defer os.Remove(f)
+	}
+
+	importPkg(t, "./testdata/issue25301")
+}

vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter_test.go

@@ -0,0 +1,484 @@
+// 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 file is a copy of $GOROOT/src/go/internal/gcimporter/gcimporter_test.go,
+// adjusted to make it build with code from (std lib) internal/testenv copied.
+
+package gcimporter
+
+import (
+	"bytes"
+	"fmt"
+	"go/types"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+)
+
+// ----------------------------------------------------------------------------
+// The following three functions (Builder, HasGoBuild, MustHaveGoBuild) were
+// copied from $GOROOT/src/internal/testenv since that package is not available
+// in x/tools.
+
+// Builder reports the name of the builder running this test
+// (for example, "linux-amd64" or "windows-386-gce").
+// If the test is not running on the build infrastructure,
+// Builder returns the empty string.
+func Builder() string {
+	return os.Getenv("GO_BUILDER_NAME")
+}
+
+// HasGoBuild reports whether the current system can build programs with ``go build''
+// and then run them with os.StartProcess or exec.Command.
+func HasGoBuild() bool {
+	switch runtime.GOOS {
+	case "android", "nacl":
+		return false
+	case "darwin":
+		if strings.HasPrefix(runtime.GOARCH, "arm") {
+			return false
+		}
+	}
+	return true
+}
+
+// MustHaveGoBuild checks that the current system can build programs with ``go build''
+// and then run them with os.StartProcess or exec.Command.
+// If not, MustHaveGoBuild calls t.Skip with an explanation.
+func MustHaveGoBuild(t *testing.T) {
+	if !HasGoBuild() {
+		t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+// ----------------------------------------------------------------------------
+
+// skipSpecialPlatforms causes the test to be skipped for platforms where
+// builders (build.golang.org) don't have access to compiled packages for
+// import.
+func skipSpecialPlatforms(t *testing.T) {
+	switch platform := runtime.GOOS + "-" + runtime.GOARCH; platform {
+	case "nacl-amd64p32",
+		"nacl-386",
+		"nacl-arm",
+		"darwin-arm",
+		"darwin-arm64":
+		t.Skipf("no compiled packages available for import on %s", platform)
+	}
+}
+
+func compile(t *testing.T, dirname, filename string) string {
+	/* testenv. */ MustHaveGoBuild(t)
+	cmd := exec.Command("go", "tool", "compile", filename)
+	cmd.Dir = dirname
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Logf("%s", out)
+		t.Fatalf("go tool compile %s failed: %s", filename, err)
+	}
+	// filename should end with ".go"
+	return filepath.Join(dirname, filename[:len(filename)-2]+"o")
+}
+
+func testPath(t *testing.T, path, srcDir string) *types.Package {
+	t0 := time.Now()
+	pkg, err := Import(make(map[string]*types.Package), path, srcDir)
+	if err != nil {
+		t.Errorf("testPath(%s): %s", path, err)
+		return nil
+	}
+	t.Logf("testPath(%s): %v", path, time.Since(t0))
+	return pkg
+}
+
+const maxTime = 30 * time.Second
+
+func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
+	dirname := filepath.Join(runtime.GOROOT(), "pkg", runtime.GOOS+"_"+runtime.GOARCH, dir)
+	list, err := ioutil.ReadDir(dirname)
+	if err != nil {
+		t.Fatalf("testDir(%s): %s", dirname, err)
+	}
+	for _, f := range list {
+		if time.Now().After(endTime) {
+			t.Log("testing time used up")
+			return
+		}
+		switch {
+		case !f.IsDir():
+			// try extensions
+			for _, ext := range pkgExts {
+				if strings.HasSuffix(f.Name(), ext) {
+					name := f.Name()[0 : len(f.Name())-len(ext)] // remove extension
+					if testPath(t, filepath.Join(dir, name), dir) != nil {
+						nimports++
+					}
+				}
+			}
+		case f.IsDir():
+			nimports += testDir(t, filepath.Join(dir, f.Name()), endTime)
+		}
+	}
+	return
+}
+
+const testfile = "exports.go"
+
+func TestImportTestdata(t *testing.T) {
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	if outFn := compile(t, "testdata", testfile); outFn != "" {
+		defer os.Remove(outFn)
+	}
+
+	// filename should end with ".go"
+	filename := testfile[:len(testfile)-3]
+	if pkg := testPath(t, "./testdata/"+filename, "."); pkg != nil {
+		// The package's Imports list must include all packages
+		// explicitly imported by testfile, plus all packages
+		// referenced indirectly via exported objects in testfile.
+		// With the textual export format (when run against Go1.6),
+		// the list may also include additional packages that are
+		// not strictly required for import processing alone (they
+		// are exported to err "on the safe side").
+		// For now, we just test the presence of a few packages
+		// that we know are there for sure.
+		got := fmt.Sprint(pkg.Imports())
+		for _, want := range []string{"go/ast", "go/token"} {
+			if !strings.Contains(got, want) {
+				t.Errorf(`Package("exports").Imports() = %s, does not contain %s`, got, want)
+			}
+		}
+	}
+}
+
+func TestVersionHandling(t *testing.T) {
+	skipSpecialPlatforms(t) // we really only need to exclude nacl platforms, but this is fine
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	const dir = "./testdata/versions"
+	list, err := ioutil.ReadDir(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, f := range list {
+		name := f.Name()
+		if !strings.HasSuffix(name, ".a") {
+			continue // not a package file
+		}
+		if strings.Contains(name, "corrupted") {
+			continue // don't process a leftover corrupted file
+		}
+		pkgpath := "./" + name[:len(name)-2]
+
+		if testing.Verbose() {
+			t.Logf("importing %s", name)
+		}
+
+		// test that export data can be imported
+		_, err := Import(make(map[string]*types.Package), pkgpath, dir)
+		if err != nil {
+			// ok to fail if it fails with a newer version error for select files
+			if strings.Contains(err.Error(), "newer version") {
+				switch name {
+				case "test_go1.11_999b.a", "test_go1.11_999i.a":
+					continue
+				}
+				// fall through
+			}
+			t.Errorf("import %q failed: %v", pkgpath, err)
+			continue
+		}
+
+		// create file with corrupted export data
+		// 1) read file
+		data, err := ioutil.ReadFile(filepath.Join(dir, name))
+		if err != nil {
+			t.Fatal(err)
+		}
+		// 2) find export data
+		i := bytes.Index(data, []byte("\n$$B\n")) + 5
+		j := bytes.Index(data[i:], []byte("\n$$\n")) + i
+		if i < 0 || j < 0 || i > j {
+			t.Fatalf("export data section not found (i = %d, j = %d)", i, j)
+		}
+		// 3) corrupt the data (increment every 7th byte)
+		for k := j - 13; k >= i; k -= 7 {
+			data[k]++
+		}
+		// 4) write the file
+		pkgpath += "_corrupted"
+		filename := filepath.Join(dir, pkgpath) + ".a"
+		ioutil.WriteFile(filename, data, 0666)
+		defer os.Remove(filename)
+
+		// test that importing the corrupted file results in an error
+		_, err = Import(make(map[string]*types.Package), pkgpath, dir)
+		if err == nil {
+			t.Errorf("import corrupted %q succeeded", pkgpath)
+		} else if msg := err.Error(); !strings.Contains(msg, "version skew") {
+			t.Errorf("import %q error incorrect (%s)", pkgpath, msg)
+		}
+	}
+}
+
+func TestImportStdLib(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	dt := maxTime
+	if testing.Short() && /* testenv. */ Builder() == "" {
+		dt = 10 * time.Millisecond
+	}
+	nimports := testDir(t, "", time.Now().Add(dt)) // installed packages
+	t.Logf("tested %d imports", nimports)
+}
+
+func TestIssue5815(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	pkg := importPkg(t, "strings")
+
+	scope := pkg.Scope()
+	for _, name := range scope.Names() {
+		obj := scope.Lookup(name)
+		if obj.Pkg() == nil {
+			t.Errorf("no pkg for %s", obj)
+		}
+		if tname, _ := obj.(*types.TypeName); tname != nil {
+			named := tname.Type().(*types.Named)
+			for i := 0; i < named.NumMethods(); i++ {
+				m := named.Method(i)
+				if m.Pkg() == nil {
+					t.Errorf("no pkg for %s", m)
+				}
+			}
+		}
+	}
+}
+
+// Smoke test to ensure that imported methods get the correct package.
+func TestCorrectMethodPackage(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	imports := make(map[string]*types.Package)
+	_, err := Import(imports, "net/http", ".")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mutex := imports["sync"].Scope().Lookup("Mutex").(*types.TypeName).Type()
+	mset := types.NewMethodSet(types.NewPointer(mutex)) // methods of *sync.Mutex
+	sel := mset.Lookup(nil, "Lock")
+	lock := sel.Obj().(*types.Func)
+	if got, want := lock.Pkg().Path(), "sync"; got != want {
+		t.Errorf("got package path %q; want %q", got, want)
+	}
+}
+
+func TestIssue13566(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	if f := compile(t, "testdata", "a.go"); f != "" {
+		defer os.Remove(f)
+	}
+	if f := compile(t, "testdata", "b.go"); f != "" {
+		defer os.Remove(f)
+	}
+
+	// import must succeed (test for issue at hand)
+	pkg := importPkg(t, "./testdata/b")
+
+	// make sure all indirectly imported packages have names
+	for _, imp := range pkg.Imports() {
+		if imp.Name() == "" {
+			t.Errorf("no name for %s package", imp.Path())
+		}
+	}
+}
+
+func TestIssue13898(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// import go/internal/gcimporter which imports go/types partially
+	imports := make(map[string]*types.Package)
+	_, err := Import(imports, "go/internal/gcimporter", ".")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// look for go/types package
+	var goTypesPkg *types.Package
+	for path, pkg := range imports {
+		if path == "go/types" {
+			goTypesPkg = pkg
+			break
+		}
+	}
+	if goTypesPkg == nil {
+		t.Fatal("go/types not found")
+	}
+
+	// look for go/types.Object type
+	obj := lookupObj(t, goTypesPkg.Scope(), "Object")
+	typ, ok := obj.Type().(*types.Named)
+	if !ok {
+		t.Fatalf("go/types.Object type is %v; wanted named type", typ)
+	}
+
+	// lookup go/types.Object.Pkg method
+	m, index, indirect := types.LookupFieldOrMethod(typ, false, nil, "Pkg")
+	if m == nil {
+		t.Fatalf("go/types.Object.Pkg not found (index = %v, indirect = %v)", index, indirect)
+	}
+
+	// the method must belong to go/types
+	if m.Pkg().Path() != "go/types" {
+		t.Fatalf("found %v; want go/types", m.Pkg())
+	}
+}
+
+func TestIssue15517(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	if f := compile(t, "testdata", "p.go"); f != "" {
+		defer os.Remove(f)
+	}
+
+	// Multiple imports of p must succeed without redeclaration errors.
+	// We use an import path that's not cleaned up so that the eventual
+	// file path for the package is different from the package path; this
+	// will expose the error if it is present.
+	//
+	// (Issue: Both the textual and the binary importer used the file path
+	// of the package to be imported as key into the shared packages map.
+	// However, the binary importer then used the package path to identify
+	// the imported package to mark it as complete; effectively marking the
+	// wrong package as complete. By using an "unclean" package path, the
+	// file and package path are different, exposing the problem if present.
+	// The same issue occurs with vendoring.)
+	imports := make(map[string]*types.Package)
+	for i := 0; i < 3; i++ {
+		if _, err := Import(imports, "./././testdata/p", "."); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestIssue15920(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	if f := compile(t, "testdata", "issue15920.go"); f != "" {
+		defer os.Remove(f)
+	}
+
+	importPkg(t, "./testdata/issue15920")
+}
+
+func TestIssue20046(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	if f := compile(t, "testdata", "issue20046.go"); f != "" {
+		defer os.Remove(f)
+	}
+
+	// "./issue20046".V.M must exist
+	pkg := importPkg(t, "./testdata/issue20046")
+	obj := lookupObj(t, pkg.Scope(), "V")
+	if m, index, indirect := types.LookupFieldOrMethod(obj.Type(), false, nil, "M"); m == nil {
+		t.Fatalf("V.M not found (index = %v, indirect = %v)", index, indirect)
+	}
+}
+
+func importPkg(t *testing.T, path string) *types.Package {
+	pkg, err := Import(make(map[string]*types.Package), path, ".")
+	if err != nil {
+		t.Fatal(err)
+	}
+	return pkg
+}
+
+func lookupObj(t *testing.T, scope *types.Scope, name string) types.Object {
+	if obj := scope.Lookup(name); obj != nil {
+		return obj
+	}
+	t.Fatalf("%s not found", name)
+	return nil
+}

vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go

@@ -0,0 +1,598 @@
+// Copyright 2018 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.
+
+// Indexed package import.
+// See cmd/compile/internal/gc/iexport.go for the export data format.
+
+// This file is a copy of $GOROOT/src/go/internal/gcimporter/iimport.go.
+
+package gcimporter
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"io"
+	"sort"
+)
+
+type intReader struct {
+	*bytes.Reader
+	path string
+}
+
+func (r *intReader) int64() int64 {
+	i, err := binary.ReadVarint(r.Reader)
+	if err != nil {
+		errorf("import %q: read varint error: %v", r.path, err)
+	}
+	return i
+}
+
+func (r *intReader) uint64() uint64 {
+	i, err := binary.ReadUvarint(r.Reader)
+	if err != nil {
+		errorf("import %q: read varint error: %v", r.path, err)
+	}
+	return i
+}
+
+const predeclReserved = 32
+
+type itag uint64
+
+const (
+	// Types
+	definedType itag = iota
+	pointerType
+	sliceType
+	arrayType
+	chanType
+	mapType
+	signatureType
+	structType
+	interfaceType
+)
+
+// IImportData imports a package from the serialized package data
+// and returns the number of bytes consumed and a reference to the package.
+// If the export data version is not recognized or the format is otherwise
+// compromised, an error is returned.
+func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
+	const currentVersion = 0
+	version := -1
+	defer func() {
+		if e := recover(); e != nil {
+			if version > currentVersion {
+				err = fmt.Errorf("cannot import %q (%v), export data is newer version - update tool", path, e)
+			} else {
+				err = fmt.Errorf("cannot import %q (%v), possibly version skew - reinstall package", path, e)
+			}
+		}
+	}()
+
+	r := &intReader{bytes.NewReader(data), path}
+
+	version = int(r.uint64())
+	switch version {
+	case currentVersion:
+	default:
+		errorf("unknown iexport format version %d", version)
+	}
+
+	sLen := int64(r.uint64())
+	dLen := int64(r.uint64())
+
+	whence, _ := r.Seek(0, io.SeekCurrent)
+	stringData := data[whence : whence+sLen]
+	declData := data[whence+sLen : whence+sLen+dLen]
+	r.Seek(sLen+dLen, io.SeekCurrent)
+
+	p := iimporter{
+		ipath: path,
+
+		stringData:  stringData,
+		stringCache: make(map[uint64]string),
+		pkgCache:    make(map[uint64]*types.Package),
+
+		declData: declData,
+		pkgIndex: make(map[*types.Package]map[string]uint64),
+		typCache: make(map[uint64]types.Type),
+
+		fake: fakeFileSet{
+			fset:  fset,
+			files: make(map[string]*token.File),
+		},
+	}
+
+	for i, pt := range predeclared {
+		p.typCache[uint64(i)] = pt
+	}
+
+	pkgList := make([]*types.Package, r.uint64())
+	for i := range pkgList {
+		pkgPathOff := r.uint64()
+		pkgPath := p.stringAt(pkgPathOff)
+		pkgName := p.stringAt(r.uint64())
+		_ = r.uint64() // package height; unused by go/types
+
+		if pkgPath == "" {
+			pkgPath = path
+		}
+		pkg := imports[pkgPath]
+		if pkg == nil {
+			pkg = types.NewPackage(pkgPath, pkgName)
+			imports[pkgPath] = pkg
+		} else if pkg.Name() != pkgName {
+			errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
+		}
+
+		p.pkgCache[pkgPathOff] = pkg
+
+		nameIndex := make(map[string]uint64)
+		for nSyms := r.uint64(); nSyms > 0; nSyms-- {
+			name := p.stringAt(r.uint64())
+			nameIndex[name] = r.uint64()
+		}
+
+		p.pkgIndex[pkg] = nameIndex
+		pkgList[i] = pkg
+	}
+
+	localpkg := pkgList[0]
+
+	names := make([]string, 0, len(p.pkgIndex[localpkg]))
+	for name := range p.pkgIndex[localpkg] {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	for _, name := range names {
+		p.doDecl(localpkg, name)
+	}
+
+	for _, typ := range p.interfaceList {
+		typ.Complete()
+	}
+
+	// record all referenced packages as imports
+	list := append(([]*types.Package)(nil), pkgList[1:]...)
+	sort.Sort(byPath(list))
+	localpkg.SetImports(list)
+
+	// package was imported completely and without errors
+	localpkg.MarkComplete()
+
+	consumed, _ := r.Seek(0, io.SeekCurrent)
+	return int(consumed), localpkg, nil
+}
+
+type iimporter struct {
+	ipath string
+
+	stringData  []byte
+	stringCache map[uint64]string
+	pkgCache    map[uint64]*types.Package
+
+	declData []byte
+	pkgIndex map[*types.Package]map[string]uint64
+	typCache map[uint64]types.Type
+
+	fake          fakeFileSet
+	interfaceList []*types.Interface
+}
+
+func (p *iimporter) doDecl(pkg *types.Package, name string) {
+	// See if we've already imported this declaration.
+	if obj := pkg.Scope().Lookup(name); obj != nil {
+		return
+	}
+
+	off, ok := p.pkgIndex[pkg][name]
+	if !ok {
+		errorf("%v.%v not in index", pkg, name)
+	}
+
+	r := &importReader{p: p, currPkg: pkg}
+	r.declReader.Reset(p.declData[off:])
+
+	r.obj(name)
+}
+
+func (p *iimporter) stringAt(off uint64) string {
+	if s, ok := p.stringCache[off]; ok {
+		return s
+	}
+
+	slen, n := binary.Uvarint(p.stringData[off:])
+	if n <= 0 {
+		errorf("varint failed")
+	}
+	spos := off + uint64(n)
+	s := string(p.stringData[spos : spos+slen])
+	p.stringCache[off] = s
+	return s
+}
+
+func (p *iimporter) pkgAt(off uint64) *types.Package {
+	if pkg, ok := p.pkgCache[off]; ok {
+		return pkg
+	}
+	path := p.stringAt(off)
+	errorf("missing package %q in %q", path, p.ipath)
+	return nil
+}
+
+func (p *iimporter) typAt(off uint64, base *types.Named) types.Type {
+	if t, ok := p.typCache[off]; ok && (base == nil || !isInterface(t)) {
+		return t
+	}
+
+	if off < predeclReserved {
+		errorf("predeclared type missing from cache: %v", off)
+	}
+
+	r := &importReader{p: p}
+	r.declReader.Reset(p.declData[off-predeclReserved:])
+	t := r.doType(base)
+
+	if base == nil || !isInterface(t) {
+		p.typCache[off] = t
+	}
+	return t
+}
+
+type importReader struct {
+	p          *iimporter
+	declReader bytes.Reader
+	currPkg    *types.Package
+	prevFile   string
+	prevLine   int64
+}
+
+func (r *importReader) obj(name string) {
+	tag := r.byte()
+	pos := r.pos()
+
+	switch tag {
+	case 'A':
+		typ := r.typ()
+
+		r.declare(types.NewTypeName(pos, r.currPkg, name, typ))
+
+	case 'C':
+		typ, val := r.value()
+
+		r.declare(types.NewConst(pos, r.currPkg, name, typ, val))
+
+	case 'F':
+		sig := r.signature(nil)
+
+		r.declare(types.NewFunc(pos, r.currPkg, name, sig))
+
+	case 'T':
+		// Types can be recursive. We need to setup a stub
+		// declaration before recursing.
+		obj := types.NewTypeName(pos, r.currPkg, name, nil)
+		named := types.NewNamed(obj, nil, nil)
+		r.declare(obj)
+
+		underlying := r.p.typAt(r.uint64(), named).Underlying()
+		named.SetUnderlying(underlying)
+
+		if !isInterface(underlying) {
+			for n := r.uint64(); n > 0; n-- {
+				mpos := r.pos()
+				mname := r.ident()
+				recv := r.param()
+				msig := r.signature(recv)
+
+				named.AddMethod(types.NewFunc(mpos, r.currPkg, mname, msig))
+			}
+		}
+
+	case 'V':
+		typ := r.typ()
+
+		r.declare(types.NewVar(pos, r.currPkg, name, typ))
+
+	default:
+		errorf("unexpected tag: %v", tag)
+	}
+}
+
+func (r *importReader) declare(obj types.Object) {
+	obj.Pkg().Scope().Insert(obj)
+}
+
+func (r *importReader) value() (typ types.Type, val constant.Value) {
+	typ = r.typ()
+
+	switch b := typ.Underlying().(*types.Basic); b.Info() & types.IsConstType {
+	case types.IsBoolean:
+		val = constant.MakeBool(r.bool())
+
+	case types.IsString:
+		val = constant.MakeString(r.string())
+
+	case types.IsInteger:
+		val = r.mpint(b)
+
+	case types.IsFloat:
+		val = r.mpfloat(b)
+
+	case types.IsComplex:
+		re := r.mpfloat(b)
+		im := r.mpfloat(b)
+		val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
+
+	default:
+		errorf("unexpected type %v", typ) // panics
+		panic("unreachable")
+	}
+
+	return
+}
+
+func intSize(b *types.Basic) (signed bool, maxBytes uint) {
+	if (b.Info() & types.IsUntyped) != 0 {
+		return true, 64
+	}
+
+	switch b.Kind() {
+	case types.Float32, types.Complex64:
+		return true, 3
+	case types.Float64, types.Complex128:
+		return true, 7
+	}
+
+	signed = (b.Info() & types.IsUnsigned) == 0
+	switch b.Kind() {
+	case types.Int8, types.Uint8:
+		maxBytes = 1
+	case types.Int16, types.Uint16:
+		maxBytes = 2
+	case types.Int32, types.Uint32:
+		maxBytes = 4
+	default:
+		maxBytes = 8
+	}
+
+	return
+}
+
+func (r *importReader) mpint(b *types.Basic) constant.Value {
+	signed, maxBytes := intSize(b)
+
+	maxSmall := 256 - maxBytes
+	if signed {
+		maxSmall = 256 - 2*maxBytes
+	}
+	if maxBytes == 1 {
+		maxSmall = 256
+	}
+
+	n, _ := r.declReader.ReadByte()
+	if uint(n) < maxSmall {
+		v := int64(n)
+		if signed {
+			v >>= 1
+			if n&1 != 0 {
+				v = ^v
+			}
+		}
+		return constant.MakeInt64(v)
+	}
+
+	v := -n
+	if signed {
+		v = -(n &^ 1) >> 1
+	}
+	if v < 1 || uint(v) > maxBytes {
+		errorf("weird decoding: %v, %v => %v", n, signed, v)
+	}
+
+	buf := make([]byte, v)
+	io.ReadFull(&r.declReader, buf)
+
+	// convert to little endian
+	// TODO(gri) go/constant should have a more direct conversion function
+	//           (e.g., once it supports a big.Float based implementation)
+	for i, j := 0, len(buf)-1; i < j; i, j = i+1, j-1 {
+		buf[i], buf[j] = buf[j], buf[i]
+	}
+
+	x := constant.MakeFromBytes(buf)
+	if signed && n&1 != 0 {
+		x = constant.UnaryOp(token.SUB, x, 0)
+	}
+	return x
+}
+
+func (r *importReader) mpfloat(b *types.Basic) constant.Value {
+	x := r.mpint(b)
+	if constant.Sign(x) == 0 {
+		return x
+	}
+
+	exp := r.int64()
+	switch {
+	case exp > 0:
+		x = constant.Shift(x, token.SHL, uint(exp))
+	case exp < 0:
+		d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp))
+		x = constant.BinaryOp(x, token.QUO, d)
+	}
+	return x
+}
+
+func (r *importReader) ident() string {
+	return r.string()
+}
+
+func (r *importReader) qualifiedIdent() (*types.Package, string) {
+	name := r.string()
+	pkg := r.pkg()
+	return pkg, name
+}
+
+func (r *importReader) pos() token.Pos {
+	delta := r.int64()
+	if delta != deltaNewFile {
+		r.prevLine += delta
+	} else if l := r.int64(); l == -1 {
+		r.prevLine += deltaNewFile
+	} else {
+		r.prevFile = r.string()
+		r.prevLine = l
+	}
+
+	if r.prevFile == "" && r.prevLine == 0 {
+		return token.NoPos
+	}
+
+	return r.p.fake.pos(r.prevFile, int(r.prevLine))
+}
+
+func (r *importReader) typ() types.Type {
+	return r.p.typAt(r.uint64(), nil)
+}
+
+func isInterface(t types.Type) bool {
+	_, ok := t.(*types.Interface)
+	return ok
+}
+
+func (r *importReader) pkg() *types.Package { return r.p.pkgAt(r.uint64()) }
+func (r *importReader) string() string      { return r.p.stringAt(r.uint64()) }
+
+func (r *importReader) doType(base *types.Named) types.Type {
+	switch k := r.kind(); k {
+	default:
+		errorf("unexpected kind tag in %q: %v", r.p.ipath, k)
+		return nil
+
+	case definedType:
+		pkg, name := r.qualifiedIdent()
+		r.p.doDecl(pkg, name)
+		return pkg.Scope().Lookup(name).(*types.TypeName).Type()
+	case pointerType:
+		return types.NewPointer(r.typ())
+	case sliceType:
+		return types.NewSlice(r.typ())
+	case arrayType:
+		n := r.uint64()
+		return types.NewArray(r.typ(), int64(n))
+	case chanType:
+		dir := chanDir(int(r.uint64()))
+		return types.NewChan(dir, r.typ())
+	case mapType:
+		return types.NewMap(r.typ(), r.typ())
+	case signatureType:
+		r.currPkg = r.pkg()
+		return r.signature(nil)
+
+	case structType:
+		r.currPkg = r.pkg()
+
+		fields := make([]*types.Var, r.uint64())
+		tags := make([]string, len(fields))
+		for i := range fields {
+			fpos := r.pos()
+			fname := r.ident()
+			ftyp := r.typ()
+			emb := r.bool()
+			tag := r.string()
+
+			fields[i] = types.NewField(fpos, r.currPkg, fname, ftyp, emb)
+			tags[i] = tag
+		}
+		return types.NewStruct(fields, tags)
+
+	case interfaceType:
+		r.currPkg = r.pkg()
+
+		embeddeds := make([]types.Type, r.uint64())
+		for i := range embeddeds {
+			_ = r.pos()
+			embeddeds[i] = r.typ()
+		}
+
+		methods := make([]*types.Func, r.uint64())
+		for i := range methods {
+			mpos := r.pos()
+			mname := r.ident()
+
+			// TODO(mdempsky): Matches bimport.go, but I
+			// don't agree with this.
+			var recv *types.Var
+			if base != nil {
+				recv = types.NewVar(token.NoPos, r.currPkg, "", base)
+			}
+
+			msig := r.signature(recv)
+			methods[i] = types.NewFunc(mpos, r.currPkg, mname, msig)
+		}
+
+		typ := newInterface(methods, embeddeds)
+		r.p.interfaceList = append(r.p.interfaceList, typ)
+		return typ
+	}
+}
+
+func (r *importReader) kind() itag {
+	return itag(r.uint64())
+}
+
+func (r *importReader) signature(recv *types.Var) *types.Signature {
+	params := r.paramList()
+	results := r.paramList()
+	variadic := params.Len() > 0 && r.bool()
+	return types.NewSignature(recv, params, results, variadic)
+}
+
+func (r *importReader) paramList() *types.Tuple {
+	xs := make([]*types.Var, r.uint64())
+	for i := range xs {
+		xs[i] = r.param()
+	}
+	return types.NewTuple(xs...)
+}
+
+func (r *importReader) param() *types.Var {
+	pos := r.pos()
+	name := r.ident()
+	typ := r.typ()
+	return types.NewParam(pos, r.currPkg, name, typ)
+}
+
+func (r *importReader) bool() bool {
+	return r.uint64() != 0
+}
+
+func (r *importReader) int64() int64 {
+	n, err := binary.ReadVarint(&r.declReader)
+	if err != nil {
+		errorf("readVarint: %v", err)
+	}
+	return n
+}
+
+func (r *importReader) uint64() uint64 {
+	n, err := binary.ReadUvarint(&r.declReader)
+	if err != nil {
+		errorf("readUvarint: %v", err)
+	}
+	return n
+}
+
+func (r *importReader) byte() byte {
+	x, err := r.declReader.ReadByte()
+	if err != nil {
+		errorf("declReader.ReadByte: %v", err)
+	}
+	return x
+}

vendor/golang.org/x/tools/go/internal/gcimporter/isAlias18.go

@@ -0,0 +1,13 @@
+// Copyright 2017 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 !go1.9
+
+package gcimporter
+
+import "go/types"
+
+func isAlias(obj *types.TypeName) bool {
+	return false // there are no type aliases before Go 1.9
+}

vendor/golang.org/x/tools/go/internal/gcimporter/isAlias19.go

@@ -0,0 +1,13 @@
+// Copyright 2017 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 go1.9
+
+package gcimporter
+
+import "go/types"
+
+func isAlias(obj *types.TypeName) bool {
+	return obj.IsAlias()
+}

vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go

@@ -0,0 +1,21 @@
+// Copyright 2018 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 !go1.11
+
+package gcimporter
+
+import "go/types"
+
+func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
+	named := make([]*types.Named, len(embeddeds))
+	for i, e := range embeddeds {
+		var ok bool
+		named[i], ok = e.(*types.Named)
+		if !ok {
+			panic("embedding of non-defined interfaces in interfaces is not supported before Go 1.11")
+		}
+	}
+	return types.NewInterface(methods, named)
+}

vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go

@@ -0,0 +1,13 @@
+// Copyright 2018 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 go1.11
+
+package gcimporter
+
+import "go/types"
+
+func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
+	return types.NewInterfaceType(methods, embeddeds)
+}

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/a.go

@@ -0,0 +1,14 @@
+// Copyright 2016 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.
+
+// Input for TestIssue13566
+
+package a
+
+import "encoding/json"
+
+type A struct {
+	a    *A
+	json json.RawMessage
+}

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/b.go

@@ -0,0 +1,11 @@
+// Copyright 2016 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.
+
+// Input for TestIssue13566
+
+package b
+
+import "./a"
+
+type A a.A

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/exports.go

@@ -0,0 +1,89 @@
+// 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 file is used to generate an object file which
+// serves as test file for gcimporter_test.go.
+
+package exports
+
+import (
+	"go/ast"
+)
+
+// Issue 3682: Correctly read dotted identifiers from export data.
+const init1 = 0
+
+func init() {}
+
+const (
+	C0 int = 0
+	C1     = 3.14159265
+	C2     = 2.718281828i
+	C3     = -123.456e-789
+	C4     = +123.456E+789
+	C5     = 1234i
+	C6     = "foo\n"
+	C7     = `bar\n`
+)
+
+type (
+	T1  int
+	T2  [10]int
+	T3  []int
+	T4  *int
+	T5  chan int
+	T6a chan<- int
+	T6b chan (<-chan int)
+	T6c chan<- (chan int)
+	T7  <-chan *ast.File
+	T8  struct{}
+	T9  struct {
+		a    int
+		b, c float32
+		d    []string `go:"tag"`
+	}
+	T10 struct {
+		T8
+		T9
+		_ *T10
+	}
+	T11 map[int]string
+	T12 interface{}
+	T13 interface {
+		m1()
+		m2(int) float32
+	}
+	T14 interface {
+		T12
+		T13
+		m3(x ...struct{}) []T9
+	}
+	T15 func()
+	T16 func(int)
+	T17 func(x int)
+	T18 func() float32
+	T19 func() (x float32)
+	T20 func(...interface{})
+	T21 struct{ next *T21 }
+	T22 struct{ link *T23 }
+	T23 struct{ link *T22 }
+	T24 *T24
+	T25 *T26
+	T26 *T27
+	T27 *T25
+	T28 func(T28) T28
+)
+
+var (
+	V0 int
+	V1 = -991.0
+)
+
+func F1()         {}
+func F2(x int)    {}
+func F3() int     { return 0 }
+func F4() float32 { return 0 }
+func F5(a, b, c int, u, v, w struct{ x, y T1 }, more ...interface{}) (p, q, r chan<- T10)
+
+func (p *T1) M1()

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/issue15920.go

@@ -0,0 +1,11 @@
+// Copyright 2016 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
+
+// The underlying type of Error is the underlying type of error.
+// Make sure we can import this again without problems.
+type Error error
+
+func F() Error { return nil }

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/issue20046.go

@@ -0,0 +1,9 @@
+// Copyright 2017 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
+
+var V interface {
+	M()
+}

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/issue25301.go

@@ -0,0 +1,17 @@
+// Copyright 2018 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 issue25301
+
+type (
+	A = interface {
+		M()
+	}
+	T interface {
+		A
+	}
+	S struct{}
+)
+
+func (S) M() { println("m") }

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/p.go

@@ -0,0 +1,13 @@
+// Copyright 2016 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.
+
+// Input for TestIssue15517
+
+package p
+
+const C = 0
+
+var V int
+
+func F() {}

vendor/golang.org/x/tools/go/internal/gcimporter/testdata/versions/test.go

@@ -0,0 +1,30 @@
+// Copyright 2016 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 file is a copy of $GOROOT/src/go/internal/gcimporter/testdata/versions.test.go.
+
+// To create a test case for a new export format version,
+// build this package with the latest compiler and store
+// the resulting .a file appropriately named in the versions
+// directory. The VersionHandling test will pick it up.
+//
+// In the testdata/versions:
+//
+// go build -o test_go1.$X_$Y.a test.go
+//
+// with $X = Go version and $Y = export format version
+// (add 'b' or 'i' to distinguish between binary and
+// indexed format starting with 1.11 as long as both
+// formats are supported).
+//
+// Make sure this source is extended such that it exercises
+// whatever export format change has taken place.
+
+package test
+
+// Any release before and including Go 1.7 didn't encode
+// the package for a blank struct field.
+type BlankField struct {
+	_ int
+}

vendor/golang.org/x/tools/go/loader/cgo.go

@@ -0,0 +1,207 @@
+// 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.
+
+package loader
+
+// This file handles cgo preprocessing of files containing `import "C"`.
+//
+// DESIGN
+//
+// The approach taken is to run the cgo processor on the package's
+// CgoFiles and parse the output, faking the filenames of the
+// resulting ASTs so that the synthetic file containing the C types is
+// called "C" (e.g. "~/go/src/net/C") and the preprocessed files
+// have their original names (e.g. "~/go/src/net/cgo_unix.go"),
+// not the names of the actual temporary files.
+//
+// The advantage of this approach is its fidelity to 'go build'.  The
+// downside is that the token.Position.Offset for each AST node is
+// incorrect, being an offset within the temporary file.  Line numbers
+// should still be correct because of the //line comments.
+//
+// The logic of this file is mostly plundered from the 'go build'
+// tool, which also invokes the cgo preprocessor.
+//
+//
+// REJECTED ALTERNATIVE
+//
+// An alternative approach that we explored is to extend go/types'
+// Importer mechanism to provide the identity of the importing package
+// so that each time `import "C"` appears it resolves to a different
+// synthetic package containing just the objects needed in that case.
+// The loader would invoke cgo but parse only the cgo_types.go file
+// defining the package-level objects, discarding the other files
+// resulting from preprocessing.
+//
+// The benefit of this approach would have been that source-level
+// syntax information would correspond exactly to the original cgo
+// file, with no preprocessing involved, making source tools like
+// godoc, guru, and eg happy.  However, the approach was rejected
+// due to the additional complexity it would impose on go/types.  (It
+// made for a beautiful demo, though.)
+//
+// cgo files, despite their *.go extension, are not legal Go source
+// files per the specification since they may refer to unexported
+// members of package "C" such as C.int.  Also, a function such as
+// C.getpwent has in effect two types, one matching its C type and one
+// which additionally returns (errno C.int).  The cgo preprocessor
+// uses name mangling to distinguish these two functions in the
+// processed code, but go/types would need to duplicate this logic in
+// its handling of function calls, analogous to the treatment of map
+// lookups in which y=m[k] and y,ok=m[k] are both legal.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/parser"
+	"go/token"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+// processCgoFiles invokes the cgo preprocessor on bp.CgoFiles, parses
+// the output and returns the resulting ASTs.
+//
+func processCgoFiles(bp *build.Package, fset *token.FileSet, DisplayPath func(path string) string, mode parser.Mode) ([]*ast.File, error) {
+	tmpdir, err := ioutil.TempDir("", strings.Replace(bp.ImportPath, "/", "_", -1)+"_C")
+	if err != nil {
+		return nil, err
+	}
+	defer os.RemoveAll(tmpdir)
+
+	pkgdir := bp.Dir
+	if DisplayPath != nil {
+		pkgdir = DisplayPath(pkgdir)
+	}
+
+	cgoFiles, cgoDisplayFiles, err := runCgo(bp, pkgdir, tmpdir)
+	if err != nil {
+		return nil, err
+	}
+	var files []*ast.File
+	for i := range cgoFiles {
+		rd, err := os.Open(cgoFiles[i])
+		if err != nil {
+			return nil, err
+		}
+		display := filepath.Join(bp.Dir, cgoDisplayFiles[i])
+		f, err := parser.ParseFile(fset, display, rd, mode)
+		rd.Close()
+		if err != nil {
+			return nil, err
+		}
+		files = append(files, f)
+	}
+	return files, nil
+}
+
+var cgoRe = regexp.MustCompile(`[/\\:]`)
+
+// runCgo invokes the cgo preprocessor on bp.CgoFiles and returns two
+// lists of files: the resulting processed files (in temporary
+// directory tmpdir) and the corresponding names of the unprocessed files.
+//
+// runCgo is adapted from (*builder).cgo in
+// $GOROOT/src/cmd/go/build.go, but these features are unsupported:
+// Objective C, CGOPKGPATH, CGO_FLAGS.
+//
+func runCgo(bp *build.Package, pkgdir, tmpdir string) (files, displayFiles []string, err error) {
+	cgoCPPFLAGS, _, _, _ := cflags(bp, true)
+	_, cgoexeCFLAGS, _, _ := cflags(bp, false)
+
+	if len(bp.CgoPkgConfig) > 0 {
+		pcCFLAGS, err := pkgConfigFlags(bp)
+		if err != nil {
+			return nil, nil, err
+		}
+		cgoCPPFLAGS = append(cgoCPPFLAGS, pcCFLAGS...)
+	}
+
+	// Allows including _cgo_export.h from .[ch] files in the package.
+	cgoCPPFLAGS = append(cgoCPPFLAGS, "-I", tmpdir)
+
+	// _cgo_gotypes.go (displayed "C") contains the type definitions.
+	files = append(files, filepath.Join(tmpdir, "_cgo_gotypes.go"))
+	displayFiles = append(displayFiles, "C")
+	for _, fn := range bp.CgoFiles {
+		// "foo.cgo1.go" (displayed "foo.go") is the processed Go source.
+		f := cgoRe.ReplaceAllString(fn[:len(fn)-len("go")], "_")
+		files = append(files, filepath.Join(tmpdir, f+"cgo1.go"))
+		displayFiles = append(displayFiles, fn)
+	}
+
+	var cgoflags []string
+	if bp.Goroot && bp.ImportPath == "runtime/cgo" {
+		cgoflags = append(cgoflags, "-import_runtime_cgo=false")
+	}
+	if bp.Goroot && bp.ImportPath == "runtime/race" || bp.ImportPath == "runtime/cgo" {
+		cgoflags = append(cgoflags, "-import_syscall=false")
+	}
+
+	args := stringList(
+		"go", "tool", "cgo", "-objdir", tmpdir, cgoflags, "--",
+		cgoCPPFLAGS, cgoexeCFLAGS, bp.CgoFiles,
+	)
+	if false {
+		log.Printf("Running cgo for package %q: %s (dir=%s)", bp.ImportPath, args, pkgdir)
+	}
+	cmd := exec.Command(args[0], args[1:]...)
+	cmd.Dir = pkgdir
+	cmd.Stdout = os.Stderr
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		return nil, nil, fmt.Errorf("cgo failed: %s: %s", args, err)
+	}
+
+	return files, displayFiles, nil
+}
+
+// -- unmodified from 'go build' ---------------------------------------
+
+// Return the flags to use when invoking the C or C++ compilers, or cgo.
+func cflags(p *build.Package, def bool) (cppflags, cflags, cxxflags, ldflags []string) {
+	var defaults string
+	if def {
+		defaults = "-g -O2"
+	}
+
+	cppflags = stringList(envList("CGO_CPPFLAGS", ""), p.CgoCPPFLAGS)
+	cflags = stringList(envList("CGO_CFLAGS", defaults), p.CgoCFLAGS)
+	cxxflags = stringList(envList("CGO_CXXFLAGS", defaults), p.CgoCXXFLAGS)
+	ldflags = stringList(envList("CGO_LDFLAGS", defaults), p.CgoLDFLAGS)
+	return
+}
+
+// envList returns the value of the given environment variable broken
+// into fields, using the default value when the variable is empty.
+func envList(key, def string) []string {
+	v := os.Getenv(key)
+	if v == "" {
+		v = def
+	}
+	return strings.Fields(v)
+}
+
+// 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
+}

vendor/golang.org/x/tools/go/loader/cgo_pkgconfig.go

@@ -0,0 +1,39 @@
+// 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.
+
+package loader
+
+import (
+	"errors"
+	"fmt"
+	"go/build"
+	"os/exec"
+	"strings"
+)
+
+// pkgConfig runs pkg-config with the specified arguments and returns the flags it prints.
+func pkgConfig(mode string, pkgs []string) (flags []string, err error) {
+	cmd := exec.Command("pkg-config", append([]string{mode}, pkgs...)...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		s := fmt.Sprintf("%s failed: %v", strings.Join(cmd.Args, " "), err)
+		if len(out) > 0 {
+			s = fmt.Sprintf("%s: %s", s, out)
+		}
+		return nil, errors.New(s)
+	}
+	if len(out) > 0 {
+		flags = strings.Fields(string(out))
+	}
+	return
+}
+
+// pkgConfigFlags calls pkg-config if needed and returns the cflags
+// needed to build the package.
+func pkgConfigFlags(p *build.Package) (cflags []string, err error) {
+	if len(p.CgoPkgConfig) == 0 {
+		return nil, nil
+	}
+	return pkgConfig("--cflags", p.CgoPkgConfig)
+}

vendor/golang.org/x/tools/go/loader/doc.go

@@ -0,0 +1,205 @@
+// Copyright 2015 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 loader loads a complete Go program from source code, parsing
+// and type-checking the initial packages plus their transitive closure
+// of dependencies.  The ASTs and the derived facts are retained for
+// later use.
+//
+// THIS INTERFACE IS EXPERIMENTAL AND IS LIKELY TO CHANGE.
+//
+// The package defines two primary types: Config, which specifies a
+// set of initial packages to load and various other options; and
+// Program, which is the result of successfully loading the packages
+// specified by a configuration.
+//
+// The configuration can be set directly, but *Config provides various
+// convenience methods to simplify the common cases, each of which can
+// be called any number of times.  Finally, these are followed by a
+// call to Load() to actually load and type-check the program.
+//
+//      var conf loader.Config
+//
+//      // Use the command-line arguments to specify
+//      // a set of initial packages to load from source.
+//      // See FromArgsUsage for help.
+//      rest, err := conf.FromArgs(os.Args[1:], wantTests)
+//
+//      // Parse the specified files and create an ad hoc package with path "foo".
+//      // All files must have the same 'package' declaration.
+//      conf.CreateFromFilenames("foo", "foo.go", "bar.go")
+//
+//      // Create an ad hoc package with path "foo" from
+//      // the specified already-parsed files.
+//      // All ASTs must have the same 'package' declaration.
+//      conf.CreateFromFiles("foo", parsedFiles)
+//
+//      // Add "runtime" to the set of packages to be loaded.
+//      conf.Import("runtime")
+//
+//      // Adds "fmt" and "fmt_test" to the set of packages
+//      // to be loaded.  "fmt" will include *_test.go files.
+//      conf.ImportWithTests("fmt")
+//
+//      // Finally, load all the packages specified by the configuration.
+//      prog, err := conf.Load()
+//
+// See examples_test.go for examples of API usage.
+//
+//
+// CONCEPTS AND TERMINOLOGY
+//
+// The WORKSPACE is the set of packages accessible to the loader.  The
+// workspace is defined by Config.Build, a *build.Context.  The
+// default context treats subdirectories of $GOROOT and $GOPATH as
+// packages, but this behavior may be overridden.
+//
+// An AD HOC package is one specified as a set of source files on the
+// command line.  In the simplest case, it may consist of a single file
+// such as $GOROOT/src/net/http/triv.go.
+//
+// EXTERNAL TEST packages are those comprised of a set of *_test.go
+// files all with the same 'package foo_test' declaration, all in the
+// same directory.  (go/build.Package calls these files XTestFiles.)
+//
+// An IMPORTABLE package is one that can be referred to by some import
+// spec.  Every importable package is uniquely identified by its
+// PACKAGE PATH or just PATH, a string such as "fmt", "encoding/json",
+// or "cmd/vendor/golang.org/x/arch/x86/x86asm".  A package path
+// typically denotes a subdirectory of the workspace.
+//
+// An import declaration uses an IMPORT PATH to refer to a package.
+// Most import declarations use the package path as the import path.
+//
+// Due to VENDORING (https://golang.org/s/go15vendor), the
+// interpretation of an import path may depend on the directory in which
+// it appears.  To resolve an import path to a package path, go/build
+// must search the enclosing directories for a subdirectory named
+// "vendor".
+//
+// ad hoc packages and external test packages are NON-IMPORTABLE.  The
+// path of an ad hoc package is inferred from the package
+// declarations of its files and is therefore not a unique package key.
+// For example, Config.CreatePkgs may specify two initial ad hoc
+// packages, both with path "main".
+//
+// An AUGMENTED package is an importable package P plus all the
+// *_test.go files with same 'package foo' declaration as P.
+// (go/build.Package calls these files TestFiles.)
+//
+// The INITIAL packages are those specified in the configuration.  A
+// DEPENDENCY is a package loaded to satisfy an import in an initial
+// package or another dependency.
+//
+package loader
+
+// IMPLEMENTATION NOTES
+//
+// 'go test', in-package test files, and import cycles
+// ---------------------------------------------------
+//
+// An external test package may depend upon members of the augmented
+// package that are not in the unaugmented package, such as functions
+// that expose internals.  (See bufio/export_test.go for an example.)
+// So, the loader must ensure that for each external test package
+// it loads, it also augments the corresponding non-test package.
+//
+// The import graph over n unaugmented packages must be acyclic; the
+// import graph over n-1 unaugmented packages plus one augmented
+// package must also be acyclic.  ('go test' relies on this.)  But the
+// import graph over n augmented packages may contain cycles.
+//
+// First, all the (unaugmented) non-test packages and their
+// dependencies are imported in the usual way; the loader reports an
+// error if it detects an import cycle.
+//
+// Then, each package P for which testing is desired is augmented by
+// the list P' of its in-package test files, by calling
+// (*types.Checker).Files.  This arrangement ensures that P' may
+// reference definitions within P, but P may not reference definitions
+// within P'.  Furthermore, P' may import any other package, including
+// ones that depend upon P, without an import cycle error.
+//
+// Consider two packages A and B, both of which have lists of
+// in-package test files we'll call A' and B', and which have the
+// following import graph edges:
+//    B  imports A
+//    B' imports A
+//    A' imports B
+// This last edge would be expected to create an error were it not
+// for the special type-checking discipline above.
+// Cycles of size greater than two are possible.  For example:
+//   compress/bzip2/bzip2_test.go (package bzip2)  imports "io/ioutil"
+//   io/ioutil/tempfile_test.go   (package ioutil) imports "regexp"
+//   regexp/exec_test.go          (package regexp) imports "compress/bzip2"
+//
+//
+// Concurrency
+// -----------
+//
+// Let us define the import dependency graph as follows.  Each node is a
+// list of files passed to (Checker).Files at once.  Many of these lists
+// are the production code of an importable Go package, so those nodes
+// are labelled by the package's path.  The remaining nodes are
+// ad hoc packages and lists of in-package *_test.go files that augment
+// an importable package; those nodes have no label.
+//
+// The edges of the graph represent import statements appearing within a
+// file.  An edge connects a node (a list of files) to the node it
+// imports, which is importable and thus always labelled.
+//
+// Loading is controlled by this dependency graph.
+//
+// To reduce I/O latency, we start loading a package's dependencies
+// asynchronously as soon as we've parsed its files and enumerated its
+// imports (scanImports).  This performs a preorder traversal of the
+// import dependency graph.
+//
+// To exploit hardware parallelism, we type-check unrelated packages in
+// parallel, where "unrelated" means not ordered by the partial order of
+// the import dependency graph.
+//
+// We use a concurrency-safe non-blocking cache (importer.imported) to
+// record the results of type-checking, whether success or failure.  An
+// entry is created in this cache by startLoad the first time the
+// package is imported.  The first goroutine to request an entry becomes
+// responsible for completing the task and broadcasting completion to
+// subsequent requestors, which block until then.
+//
+// Type checking occurs in (parallel) postorder: we cannot type-check a
+// set of files until we have loaded and type-checked all of their
+// immediate dependencies (and thus all of their transitive
+// dependencies). If the input were guaranteed free of import cycles,
+// this would be trivial: we could simply wait for completion of the
+// dependencies and then invoke the typechecker.
+//
+// But as we saw in the 'go test' section above, some cycles in the
+// import graph over packages are actually legal, so long as the
+// cycle-forming edge originates in the in-package test files that
+// augment the package.  This explains why the nodes of the import
+// dependency graph are not packages, but lists of files: the unlabelled
+// nodes avoid the cycles.  Consider packages A and B where B imports A
+// and A's in-package tests AT import B.  The naively constructed import
+// graph over packages would contain a cycle (A+AT) --> B --> (A+AT) but
+// the graph over lists of files is AT --> B --> A, where AT is an
+// unlabelled node.
+//
+// Awaiting completion of the dependencies in a cyclic graph would
+// deadlock, so we must materialize the import dependency graph (as
+// importer.graph) and check whether each import edge forms a cycle.  If
+// x imports y, and the graph already contains a path from y to x, then
+// there is an import cycle, in which case the processing of x must not
+// wait for the completion of processing of y.
+//
+// When the type-checker makes a callback (doImport) to the loader for a
+// given import edge, there are two possible cases.  In the normal case,
+// the dependency has already been completely type-checked; doImport
+// does a cache lookup and returns it.  In the cyclic case, the entry in
+// the cache is still necessarily incomplete, indicating a cycle.  We
+// perform the cycle check again to obtain the error message, and return
+// the error.
+//
+// The result of using concurrency is about a 2.5x speedup for stdlib_test.
+
+// TODO(adonovan): overhaul the package documentation.

vendor/golang.org/x/tools/go/loader/example_test.go

@@ -0,0 +1,179 @@
+// Copyright 2015 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 go1.8,!go1.9 // TODO(adonovan) determine which versions we need to test here
+// +build !windows
+
+package loader_test
+
+import (
+	"fmt"
+	"go/token"
+	"log"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+
+	"golang.org/x/tools/go/loader"
+)
+
+func printProgram(prog *loader.Program) {
+	// Created packages are the initial packages specified by a call
+	// to CreateFromFilenames or CreateFromFiles.
+	var names []string
+	for _, info := range prog.Created {
+		names = append(names, info.Pkg.Path())
+	}
+	fmt.Printf("created: %s\n", names)
+
+	// Imported packages are the initial packages specified by a
+	// call to Import or ImportWithTests.
+	names = nil
+	for _, info := range prog.Imported {
+		if strings.Contains(info.Pkg.Path(), "internal") {
+			continue // skip, to reduce fragility
+		}
+		names = append(names, info.Pkg.Path())
+	}
+	sort.Strings(names)
+	fmt.Printf("imported: %s\n", names)
+
+	// InitialPackages contains the union of created and imported.
+	names = nil
+	for _, info := range prog.InitialPackages() {
+		names = append(names, info.Pkg.Path())
+	}
+	sort.Strings(names)
+	fmt.Printf("initial: %s\n", names)
+
+	// AllPackages contains all initial packages and their dependencies.
+	names = nil
+	for pkg := range prog.AllPackages {
+		names = append(names, pkg.Path())
+	}
+	sort.Strings(names)
+	fmt.Printf("all: %s\n", names)
+}
+
+func printFilenames(fset *token.FileSet, info *loader.PackageInfo) {
+	var names []string
+	for _, f := range info.Files {
+		names = append(names, filepath.Base(fset.File(f.Pos()).Name()))
+	}
+	fmt.Printf("%s.Files: %s\n", info.Pkg.Path(), names)
+}
+
+// This example loads a set of packages and all of their dependencies
+// from a typical command-line.  FromArgs parses a command line and
+// makes calls to the other methods of Config shown in the examples that
+// follow.
+func ExampleConfig_FromArgs() {
+	args := []string{"mytool", "unicode/utf8", "errors", "runtime", "--", "foo", "bar"}
+	const wantTests = false
+
+	var conf loader.Config
+	rest, err := conf.FromArgs(args[1:], wantTests)
+	prog, err := conf.Load()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Printf("rest: %s\n", rest)
+	printProgram(prog)
+	// Output:
+	// rest: [foo bar]
+	// created: []
+	// imported: [errors runtime unicode/utf8]
+	// initial: [errors runtime unicode/utf8]
+	// all: [errors runtime runtime/internal/atomic runtime/internal/sys unicode/utf8 unsafe]
+}
+
+// This example creates and type-checks a single package (without tests)
+// from a list of filenames, and loads all of its dependencies.
+// (The input files are actually only a small part of the math/cmplx package.)
+func ExampleConfig_CreateFromFilenames() {
+	var conf loader.Config
+	conf.CreateFromFilenames("math/cmplx",
+		filepath.Join(runtime.GOROOT(), "src/math/cmplx/abs.go"),
+		filepath.Join(runtime.GOROOT(), "src/math/cmplx/sin.go"))
+	prog, err := conf.Load()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	printProgram(prog)
+	// Output:
+	// created: [math/cmplx]
+	// imported: []
+	// initial: [math/cmplx]
+	// all: [math math/cmplx unsafe]
+}
+
+// In the examples below, for stability, the chosen packages are
+// relatively small, platform-independent, and low-level (and thus
+// infrequently changing).
+// The strconv package has internal and external tests.
+
+const hello = `package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello, world.")
+}
+`
+
+// This example creates and type-checks a package from a list of
+// already-parsed files, and loads all its dependencies.
+func ExampleConfig_CreateFromFiles() {
+	var conf loader.Config
+	f, err := conf.ParseFile("hello.go", hello)
+	if err != nil {
+		log.Fatal(err)
+	}
+	conf.CreateFromFiles("hello", f)
+	prog, err := conf.Load()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	printProgram(prog)
+	printFilenames(prog.Fset, prog.Package("strconv"))
+	// Output:
+	// created: [hello]
+	// imported: []
+	// initial: [hello]
+	// all: [errors fmt hello internal/race io math os reflect runtime runtime/internal/atomic runtime/internal/sys strconv sync sync/atomic syscall time unicode/utf8 unsafe]
+	// strconv.Files: [atob.go atof.go atoi.go decimal.go doc.go extfloat.go ftoa.go isprint.go itoa.go quote.go]
+}
+
+// This example imports three packages, including the tests for one of
+// them, and loads all their dependencies.
+func ExampleConfig_Import() {
+	// ImportWithTest("strconv") causes strconv to include
+	// internal_test.go, and creates an external test package,
+	// strconv_test.
+	// (Compare with the example of CreateFromFiles.)
+
+	var conf loader.Config
+	conf.Import("unicode/utf8")
+	conf.Import("errors")
+	conf.ImportWithTests("strconv")
+	prog, err := conf.Load()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	printProgram(prog)
+	printFilenames(prog.Fset, prog.Package("strconv"))
+	printFilenames(prog.Fset, prog.Package("strconv_test"))
+	// Output:
+	// created: [strconv_test]
+	// imported: [errors strconv unicode/utf8]
+	// initial: [errors strconv strconv_test unicode/utf8]
+	// all: [bufio bytes errors flag fmt internal/race io log math math/rand os reflect runtime runtime/debug runtime/internal/atomic runtime/internal/sys runtime/trace sort strconv strconv_test strings sync sync/atomic syscall testing time unicode unicode/utf8 unsafe]
+	// strconv.Files: [atob.go atof.go atoi.go decimal.go doc.go extfloat.go ftoa.go isprint.go itoa.go quote.go internal_test.go]
+	// strconv_test.Files: [atob_test.go atof_test.go atoi_test.go decimal_test.go example_test.go fp_test.go ftoa_test.go itoa_test.go quote_test.go strconv_test.go]
+}