Merge lp:~mwhudson/ubuntu/utopic/gccgo-go/build-cgo into lp:ubuntu/utopic/gccgo-go

[Michael Hudson-Doyle]

This branch builds and installs cgo. It also makes things so that "go tool cgo" works. It's probably all horrible but it's a start :)

[Michael Hudson-Doyle (mwhudson)]

Bah the diff is certainly horrible. Here's a debdiff: http://paste.ubuntu.com/8041422/

Unmerged revisions

15. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

lintian overrides

14. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

install cgo

13. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

updates

12. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

quilt updates

11. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

update version

10. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

Build cgo too

9. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

Add broken Makefile for cgo

8. By Michael Hudson-Doyle <mwhudson@narsil> on 2014-08-14

set ToolDir to something more sensible

=== modified file '.pc/applied-patches'
--- .pc/applied-patches	2014-03-26 10:50:18 +0000
+++ .pc/applied-patches	2014-08-14 02:29:21 +0000
@@ -5,3 +5,4 @@
 issue28050043_60001_70001.diff
 issue61970044_80001.diff
 issue80300043_60001.diff
+build-cgo.diff
 
=== added directory '.pc/build-cgo.diff'
=== added file '.pc/build-cgo.diff/.timestamp'
=== added directory '.pc/build-cgo.diff/src'
=== added directory '.pc/build-cgo.diff/src/cmd'
=== added directory '.pc/build-cgo.diff/src/cmd/cgo'
=== added file '.pc/build-cgo.diff/src/cmd/cgo/Makefile'
=== added file '.pc/build-cgo.diff/src/cmd/cgo/gcc.go'
--- .pc/build-cgo.diff/src/cmd/cgo/gcc.go	1970-01-01 00:00:00 +0000
+++ .pc/build-cgo.diff/src/cmd/cgo/gcc.go	2014-08-14 02:29:21 +0000
@@ -0,0 +1,1633 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Annotate Ref in Prog with C types by parsing gcc debug output.
+// Conversion of debug output to Go types.
+
+package main
+
+import (
+	"bytes"
+	"debug/dwarf"
+	"debug/elf"
+	"debug/macho"
+	"debug/pe"
+	"encoding/binary"
+	"errors"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"strconv"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+var debugDefine = flag.Bool("debug-define", false, "print relevant #defines")
+var debugGcc = flag.Bool("debug-gcc", false, "print gcc invocations")
+
+var nameToC = map[string]string{
+	"schar":         "signed char",
+	"uchar":         "unsigned char",
+	"ushort":        "unsigned short",
+	"uint":          "unsigned int",
+	"ulong":         "unsigned long",
+	"longlong":      "long long",
+	"ulonglong":     "unsigned long long",
+	"complexfloat":  "float complex",
+	"complexdouble": "double complex",
+}
+
+// cname returns the C name to use for C.s.
+// The expansions are listed in nameToC and also
+// struct_foo becomes "struct foo", and similarly for
+// union and enum.
+func cname(s string) string {
+	if t, ok := nameToC[s]; ok {
+		return t
+	}
+
+	if strings.HasPrefix(s, "struct_") {
+		return "struct " + s[len("struct_"):]
+	}
+	if strings.HasPrefix(s, "union_") {
+		return "union " + s[len("union_"):]
+	}
+	if strings.HasPrefix(s, "enum_") {
+		return "enum " + s[len("enum_"):]
+	}
+	if strings.HasPrefix(s, "sizeof_") {
+		return "sizeof(" + cname(s[len("sizeof_"):]) + ")"
+	}
+	return s
+}
+
+// DiscardCgoDirectives processes the import C preamble, and discards
+// all #cgo CFLAGS and LDFLAGS directives, so they don't make their
+// way into _cgo_export.h.
+func (f *File) DiscardCgoDirectives() {
+	linesIn := strings.Split(f.Preamble, "\n")
+	linesOut := make([]string, 0, len(linesIn))
+	for _, line := range linesIn {
+		l := strings.TrimSpace(line)
+		if len(l) < 5 || l[:4] != "#cgo" || !unicode.IsSpace(rune(l[4])) {
+			linesOut = append(linesOut, line)
+		} else {
+			linesOut = append(linesOut, "")
+		}
+	}
+	f.Preamble = strings.Join(linesOut, "\n")
+}
+
+// addToFlag appends args to flag.  All flags are later written out onto the
+// _cgo_flags file for the build system to use.
+func (p *Package) addToFlag(flag string, args []string) {
+	p.CgoFlags[flag] = append(p.CgoFlags[flag], args...)
+	if flag == "CFLAGS" {
+		// We'll also need these when preprocessing for dwarf information.
+		p.GccOptions = append(p.GccOptions, args...)
+	}
+}
+
+// splitQuoted splits the string s around each instance of one or more consecutive
+// white space characters while taking into account quotes and escaping, and
+// returns an array of substrings of s or an empty list if s contains only white space.
+// Single quotes and double quotes are recognized to prevent splitting within the
+// quoted region, and are removed from the resulting substrings. If a quote in s
+// isn't closed err will be set and r will have the unclosed argument as the
+// last element.  The backslash is used for escaping.
+//
+// For example, the following string:
+//
+//     `a b:"c d" 'e''f'  "g\""`
+//
+// Would be parsed as:
+//
+//     []string{"a", "b:c d", "ef", `g"`}
+//
+func splitQuoted(s string) (r []string, err error) {
+	var args []string
+	arg := make([]rune, len(s))
+	escaped := false
+	quoted := false
+	quote := '\x00'
+	i := 0
+	for _, r := range s {
+		switch {
+		case escaped:
+			escaped = false
+		case r == '\\':
+			escaped = true
+			continue
+		case quote != 0:
+			if r == quote {
+				quote = 0
+				continue
+			}
+		case r == '"' || r == '\'':
+			quoted = true
+			quote = r
+			continue
+		case unicode.IsSpace(r):
+			if quoted || i > 0 {
+				quoted = false
+				args = append(args, string(arg[:i]))
+				i = 0
+			}
+			continue
+		}
+		arg[i] = r
+		i++
+	}
+	if quoted || i > 0 {
+		args = append(args, string(arg[:i]))
+	}
+	if quote != 0 {
+		err = errors.New("unclosed quote")
+	} else if escaped {
+		err = errors.New("unfinished escaping")
+	}
+	return args, err
+}
+
+var safeBytes = []byte(`+-.,/0123456789:=ABCDEFGHIJKLMNOPQRSTUVWXYZ\_abcdefghijklmnopqrstuvwxyz`)
+
+func safeName(s string) bool {
+	if s == "" {
+		return false
+	}
+	for i := 0; i < len(s); i++ {
+		if c := s[i]; c < 0x80 && bytes.IndexByte(safeBytes, c) < 0 {
+			return false
+		}
+	}
+	return true
+}
+
+// Translate rewrites f.AST, the original Go input, to remove
+// references to the imported package C, replacing them with
+// references to the equivalent Go types, functions, and variables.
+func (p *Package) Translate(f *File) {
+	for _, cref := range f.Ref {
+		// Convert C.ulong to C.unsigned long, etc.
+		cref.Name.C = cname(cref.Name.Go)
+	}
+	p.loadDefines(f)
+	needType := p.guessKinds(f)
+	if len(needType) > 0 {
+		p.loadDWARF(f, needType)
+	}
+	p.rewriteRef(f)
+}
+
+// loadDefines coerces gcc into spitting out the #defines in use
+// in the file f and saves relevant renamings in f.Name[name].Define.
+func (p *Package) loadDefines(f *File) {
+	var b bytes.Buffer
+	b.WriteString(f.Preamble)
+	b.WriteString(builtinProlog)
+	stdout := p.gccDefines(b.Bytes())
+
+	for _, line := range strings.Split(stdout, "\n") {
+		if len(line) < 9 || line[0:7] != "#define" {
+			continue
+		}
+
+		line = strings.TrimSpace(line[8:])
+
+		var key, val string
+		spaceIndex := strings.Index(line, " ")
+		tabIndex := strings.Index(line, "\t")
+
+		if spaceIndex == -1 && tabIndex == -1 {
+			continue
+		} else if tabIndex == -1 || (spaceIndex != -1 && spaceIndex < tabIndex) {
+			key = line[0:spaceIndex]
+			val = strings.TrimSpace(line[spaceIndex:])
+		} else {
+			key = line[0:tabIndex]
+			val = strings.TrimSpace(line[tabIndex:])
+		}
+
+		if n := f.Name[key]; n != nil {
+			if *debugDefine {
+				fmt.Fprintf(os.Stderr, "#define %s %s\n", key, val)
+			}
+			n.Define = val
+		}
+	}
+}
+
+// guessKinds tricks gcc into revealing the kind of each
+// name xxx for the references C.xxx in the Go input.
+// The kind is either a constant, type, or variable.
+func (p *Package) guessKinds(f *File) []*Name {
+	// Determine kinds for names we already know about,
+	// like #defines or 'struct foo', before bothering with gcc.
+	var names, needType []*Name
+	for _, n := range f.Name {
+		// If we've already found this name as a #define
+		// and we can translate it as a constant value, do so.
+		if n.Define != "" {
+			isConst := false
+			if _, err := strconv.Atoi(n.Define); err == nil {
+				isConst = true
+			} else if n.Define[0] == '"' || n.Define[0] == '\'' {
+				if _, err := parser.ParseExpr(n.Define); err == nil {
+					isConst = true
+				}
+			}
+			if isConst {
+				n.Kind = "const"
+				// Turn decimal into hex, just for consistency
+				// with enum-derived constants.  Otherwise
+				// in the cgo -godefs output half the constants
+				// are in hex and half are in whatever the #define used.
+				i, err := strconv.ParseInt(n.Define, 0, 64)
+				if err == nil {
+					n.Const = fmt.Sprintf("%#x", i)
+				} else {
+					n.Const = n.Define
+				}
+				continue
+			}
+
+			if isName(n.Define) {
+				n.C = n.Define
+			}
+		}
+
+		needType = append(needType, n)
+
+		// If this is a struct, union, or enum type name, no need to guess the kind.
+		if strings.HasPrefix(n.C, "struct ") || strings.HasPrefix(n.C, "union ") || strings.HasPrefix(n.C, "enum ") {
+			n.Kind = "type"
+			continue
+		}
+
+		// Otherwise, we'll need to find out from gcc.
+		names = append(names, n)
+	}
+
+	// Bypass gcc if there's nothing left to find out.
+	if len(names) == 0 {
+		return needType
+	}
+
+	// Coerce gcc into telling us whether each name is a type, a value, or undeclared.
+	// For names, find out whether they are integer constants.
+	// We used to look at specific warning or error messages here, but that tied the
+	// behavior too closely to specific versions of the compilers.
+	// Instead, arrange that we can infer what we need from only the presence or absence
+	// of an error on a specific line.
+	//
+	// For each name, we generate these lines, where xxx is the index in toSniff plus one.
+	//
+	//	#line xxx "not-declared"
+	//	void __cgo_f_xxx_1(void) { __typeof__(name) *__cgo_undefined__; }
+	//	#line xxx "not-type"
+	//	void __cgo_f_xxx_2(void) { name *__cgo_undefined__; }
+	//	#line xxx "not-const"
+	//	void __cgo_f_xxx_3(void) { enum { __cgo_undefined__ = (name)*1 }; }
+	//
+	// If we see an error at not-declared:xxx, the corresponding name is not declared.
+	// If we see an error at not-type:xxx, the corresponding name is a type.
+	// If we see an error at not-const:xxx, the corresponding name is not an integer constant.
+	// If we see no errors, we assume the name is an expression but not a constant
+	// (so a variable or a function).
+	//
+	// The specific input forms are chosen so that they are valid C syntax regardless of
+	// whether name denotes a type or an expression.
+
+	var b bytes.Buffer
+	b.WriteString(f.Preamble)
+	b.WriteString(builtinProlog)
+
+	for i, n := range names {
+		fmt.Fprintf(&b, "#line %d \"not-declared\"\n"+
+			"void __cgo_f_%d_1(void) { __typeof__(%s) *__cgo_undefined__; }\n"+
+			"#line %d \"not-type\"\n"+
+			"void __cgo_f_%d_2(void) { %s *__cgo_undefined__; }\n"+
+			"#line %d \"not-const\"\n"+
+			"void __cgo_f_%d_3(void) { enum { __cgo__undefined__ = (%s)*1 }; }\n",
+			i+1, i+1, n.C,
+			i+1, i+1, n.C,
+			i+1, i+1, n.C)
+	}
+	fmt.Fprintf(&b, "#line 1 \"completed\"\n"+
+		"int __cgo__1 = __cgo__2;\n")
+
+	stderr := p.gccErrors(b.Bytes())
+	if stderr == "" {
+		fatalf("%s produced no output\non input:\n%s", p.gccBaseCmd()[0], b.Bytes())
+	}
+
+	completed := false
+	sniff := make([]int, len(names))
+	const (
+		notType = 1 << iota
+		notConst
+	)
+	for _, line := range strings.Split(stderr, "\n") {
+		if !strings.Contains(line, ": error:") {
+			// we only care about errors.
+			// we tried to turn off warnings on the command line, but one never knows.
+			continue
+		}
+
+		c1 := strings.Index(line, ":")
+		if c1 < 0 {
+			continue
+		}
+		c2 := strings.Index(line[c1+1:], ":")
+		if c2 < 0 {
+			continue
+		}
+		c2 += c1 + 1
+
+		filename := line[:c1]
+		i, _ := strconv.Atoi(line[c1+1 : c2])
+		i--
+		if i < 0 || i >= len(names) {
+			continue
+		}
+
+		switch filename {
+		case "completed":
+			// Strictly speaking, there is no guarantee that seeing the error at completed:1
+			// (at the end of the file) means we've seen all the errors from earlier in the file,
+			// but usually it does. Certainly if we don't see the completed:1 error, we did
+			// not get all the errors we expected.
+			completed = true
+
+		case "not-declared":
+			error_(token.NoPos, "%s", strings.TrimSpace(line[c2+1:]))
+		case "not-type":
+			sniff[i] |= notType
+		case "not-const":
+			sniff[i] |= notConst
+		}
+	}
+
+	if !completed {
+		fatalf("%s did not produce error at completed:1\non input:\n%s", p.gccBaseCmd()[0], b.Bytes())
+	}
+
+	for i, n := range names {
+		switch sniff[i] {
+		case 0:
+			error_(token.NoPos, "could not determine kind of name for C.%s", fixGo(n.Go))
+		case notType:
+			n.Kind = "const"
+		case notConst:
+			n.Kind = "type"
+		case notConst | notType:
+			n.Kind = "not-type"
+		}
+	}
+	if nerrors > 0 {
+		fatalf("unresolved names")
+	}
+
+	needType = append(needType, names...)
+	return needType
+}
+
+// loadDWARF parses the DWARF debug information generated
+// by gcc to learn the details of the constants, variables, and types
+// being referred to as C.xxx.
+func (p *Package) loadDWARF(f *File, names []*Name) {
+	// Extract the types from the DWARF section of an object
+	// from a well-formed C program.  Gcc only generates DWARF info
+	// for symbols in the object file, so it is not enough to print the
+	// preamble and hope the symbols we care about will be there.
+	// Instead, emit
+	//	__typeof__(names[i]) *__cgo__i;
+	// for each entry in names and then dereference the type we
+	// learn for __cgo__i.
+	var b bytes.Buffer
+	b.WriteString(f.Preamble)
+	b.WriteString(builtinProlog)
+	for i, n := range names {
+		fmt.Fprintf(&b, "__typeof__(%s) *__cgo__%d;\n", n.C, i)
+		if n.Kind == "const" {
+			fmt.Fprintf(&b, "enum { __cgo_enum__%d = %s };\n", i, n.C)
+		}
+	}
+
+	// Apple's LLVM-based gcc does not include the enumeration
+	// names and values in its DWARF debug output.  In case we're
+	// using such a gcc, create a data block initialized with the values.
+	// We can read them out of the object file.
+	fmt.Fprintf(&b, "long long __cgodebug_data[] = {\n")
+	for _, n := range names {
+		if n.Kind == "const" {
+			fmt.Fprintf(&b, "\t%s,\n", n.C)
+		} else {
+			fmt.Fprintf(&b, "\t0,\n")
+		}
+	}
+	// for the last entry, we can not use 0, otherwise
+	// in case all __cgodebug_data is zero initialized,
+	// LLVM-based gcc will place the it in the __DATA.__common
+	// zero-filled section (our debug/macho doesn't support
+	// this)
+	fmt.Fprintf(&b, "\t1\n")
+	fmt.Fprintf(&b, "};\n")
+
+	d, bo, debugData := p.gccDebug(b.Bytes())
+	enumVal := make([]int64, len(debugData)/8)
+	for i := range enumVal {
+		enumVal[i] = int64(bo.Uint64(debugData[i*8:]))
+	}
+
+	// Scan DWARF info for top-level TagVariable entries with AttrName __cgo__i.
+	types := make([]dwarf.Type, len(names))
+	enums := make([]dwarf.Offset, len(names))
+	nameToIndex := make(map[*Name]int)
+	for i, n := range names {
+		nameToIndex[n] = i
+	}
+	nameToRef := make(map[*Name]*Ref)
+	for _, ref := range f.Ref {
+		nameToRef[ref.Name] = ref
+	}
+	r := d.Reader()
+	for {
+		e, err := r.Next()
+		if err != nil {
+			fatalf("reading DWARF entry: %s", err)
+		}
+		if e == nil {
+			break
+		}
+		switch e.Tag {
+		case dwarf.TagEnumerationType:
+			offset := e.Offset
+			for {
+				e, err := r.Next()
+				if err != nil {
+					fatalf("reading DWARF entry: %s", err)
+				}
+				if e.Tag == 0 {
+					break
+				}
+				if e.Tag == dwarf.TagEnumerator {
+					entryName := e.Val(dwarf.AttrName).(string)
+					if strings.HasPrefix(entryName, "__cgo_enum__") {
+						n, _ := strconv.Atoi(entryName[len("__cgo_enum__"):])
+						if 0 <= n && n < len(names) {
+							enums[n] = offset
+						}
+					}
+				}
+			}
+		case dwarf.TagVariable:
+			name, _ := e.Val(dwarf.AttrName).(string)
+			typOff, _ := e.Val(dwarf.AttrType).(dwarf.Offset)
+			if name == "" || typOff == 0 {
+				fatalf("malformed DWARF TagVariable entry")
+			}
+			if !strings.HasPrefix(name, "__cgo__") {
+				break
+			}
+			typ, err := d.Type(typOff)
+			if err != nil {
+				fatalf("loading DWARF type: %s", err)
+			}
+			t, ok := typ.(*dwarf.PtrType)
+			if !ok || t == nil {
+				fatalf("internal error: %s has non-pointer type", name)
+			}
+			i, err := strconv.Atoi(name[7:])
+			if err != nil {
+				fatalf("malformed __cgo__ name: %s", name)
+			}
+			if enums[i] != 0 {
+				t, err := d.Type(enums[i])
+				if err != nil {
+					fatalf("loading DWARF type: %s", err)
+				}
+				types[i] = t
+			} else {
+				types[i] = t.Type
+			}
+		}
+		if e.Tag != dwarf.TagCompileUnit {
+			r.SkipChildren()
+		}
+	}
+
+	// Record types and typedef information.
+	var conv typeConv
+	conv.Init(p.PtrSize, p.IntSize)
+	for i, n := range names {
+		if types[i] == nil {
+			continue
+		}
+		pos := token.NoPos
+		if ref, ok := nameToRef[n]; ok {
+			pos = ref.Pos()
+		}
+		f, fok := types[i].(*dwarf.FuncType)
+		if n.Kind != "type" && fok {
+			n.Kind = "func"
+			n.FuncType = conv.FuncType(f, pos)
+		} else {
+			n.Type = conv.Type(types[i], pos)
+			if enums[i] != 0 && n.Type.EnumValues != nil {
+				k := fmt.Sprintf("__cgo_enum__%d", i)
+				n.Kind = "const"
+				n.Const = fmt.Sprintf("%#x", n.Type.EnumValues[k])
+				// Remove injected enum to ensure the value will deep-compare
+				// equally in future loads of the same constant.
+				delete(n.Type.EnumValues, k)
+			}
+			// Prefer debug data over DWARF debug output, if we have it.
+			if n.Kind == "const" && i < len(enumVal) {
+				n.Const = fmt.Sprintf("%#x", enumVal[i])
+			}
+		}
+	}
+
+}
+
+// mangleName does name mangling to translate names
+// from the original Go source files to the names
+// used in the final Go files generated by cgo.
+func (p *Package) mangleName(n *Name) {
+	// When using gccgo variables have to be
+	// exported so that they become global symbols
+	// that the C code can refer to.
+	prefix := "_C"
+	if *gccgo && n.IsVar() {
+		prefix = "C"
+	}
+	n.Mangle = prefix + n.Kind + "_" + n.Go
+}
+
+// rewriteRef rewrites all the C.xxx references in f.AST to refer to the
+// Go equivalents, now that we have figured out the meaning of all
+// the xxx.  In *godefs or *cdefs mode, rewriteRef replaces the names
+// with full definitions instead of mangled names.
+func (p *Package) rewriteRef(f *File) {
+	// Keep a list of all the functions, to remove the ones
+	// only used as expressions and avoid generating bridge
+	// code for them.
+	functions := make(map[string]bool)
+
+	// Assign mangled names.
+	for _, n := range f.Name {
+		if n.Kind == "not-type" {
+			n.Kind = "var"
+		}
+		if n.Mangle == "" {
+			p.mangleName(n)
+		}
+		if n.Kind == "func" {
+			functions[n.Go] = false
+		}
+	}
+
+	// Now that we have all the name types filled in,
+	// scan through the Refs to identify the ones that
+	// are trying to do a ,err call.  Also check that
+	// functions are only used in calls.
+	for _, r := range f.Ref {
+		if r.Name.Kind == "const" && r.Name.Const == "" {
+			error_(r.Pos(), "unable to find value of constant C.%s", fixGo(r.Name.Go))
+		}
+		var expr ast.Expr = ast.NewIdent(r.Name.Mangle) // default
+		switch r.Context {
+		case "call", "call2":
+			if r.Name.Kind != "func" {
+				if r.Name.Kind == "type" {
+					r.Context = "type"
+					expr = r.Name.Type.Go
+					break
+				}
+				error_(r.Pos(), "call of non-function C.%s", fixGo(r.Name.Go))
+				break
+			}
+			functions[r.Name.Go] = true
+			if r.Context == "call2" {
+				if r.Name.Go == "_CMalloc" {
+					error_(r.Pos(), "no two-result form for C.malloc")
+					break
+				}
+				// Invent new Name for the two-result function.
+				n := f.Name["2"+r.Name.Go]
+				if n == nil {
+					n = new(Name)
+					*n = *r.Name
+					n.AddError = true
+					n.Mangle = "_C2func_" + n.Go
+					f.Name["2"+r.Name.Go] = n
+				}
+				expr = ast.NewIdent(n.Mangle)
+				r.Name = n
+				break
+			}
+		case "expr":
+			if r.Name.Kind == "func" {
+				// Function is being used in an expression, to e.g. pass around a C function pointer.
+				// Create a new Name for this Ref which causes the variable to be declared in Go land.
+				fpName := "fp_" + r.Name.Go
+				name := f.Name[fpName]
+				if name == nil {
+					name = &Name{
+						Go:   fpName,
+						C:    r.Name.C,
+						Kind: "fpvar",
+						Type: &Type{Size: p.PtrSize, Align: p.PtrSize, C: c("void*"), Go: ast.NewIdent("unsafe.Pointer")},
+					}
+					p.mangleName(name)
+					f.Name[fpName] = name
+				}
+				r.Name = name
+				expr = ast.NewIdent(name.Mangle)
+			} else if r.Name.Kind == "type" {
+				// Okay - might be new(T)
+				expr = r.Name.Type.Go
+			} else if r.Name.Kind == "var" {
+				expr = &ast.StarExpr{Star: (*r.Expr).Pos(), X: expr}
+			}
+
+		case "type":
+			if r.Name.Kind != "type" {
+				error_(r.Pos(), "expression C.%s used as type", fixGo(r.Name.Go))
+			} else if r.Name.Type == nil {
+				// Use of C.enum_x, C.struct_x or C.union_x without C definition.
+				// GCC won't raise an error when using pointers to such unknown types.
+				error_(r.Pos(), "type C.%s: undefined C type '%s'", fixGo(r.Name.Go), r.Name.C)
+			} else {
+				expr = r.Name.Type.Go
+			}
+		default:
+			if r.Name.Kind == "func" {
+				error_(r.Pos(), "must call C.%s", fixGo(r.Name.Go))
+			}
+		}
+		if *godefs || *cdefs {
+			// Substitute definition for mangled type name.
+			if id, ok := expr.(*ast.Ident); ok {
+				if t := typedef[id.Name]; t != nil {
+					expr = t.Go
+				}
+				if id.Name == r.Name.Mangle && r.Name.Const != "" {
+					expr = ast.NewIdent(r.Name.Const)
+				}
+			}
+		}
+
+		// Copy position information from old expr into new expr,
+		// in case expression being replaced is first on line.
+		// See golang.org/issue/6563.
+		pos := (*r.Expr).Pos()
+		switch x := expr.(type) {
+		case *ast.Ident:
+			expr = &ast.Ident{NamePos: pos, Name: x.Name}
+		}
+
+		*r.Expr = expr
+	}
+
+	// Remove functions only used as expressions, so their respective
+	// bridge functions are not generated.
+	for name, used := range functions {
+		if !used {
+			delete(f.Name, name)
+		}
+	}
+}
+
+// gccBaseCmd returns the start of the compiler command line.
+// It uses $CC if set, or else $GCC, or else the compiler recorded
+// during the initial build as defaultCC.
+// defaultCC is defined in zdefaultcc.go, written by cmd/dist.
+func (p *Package) gccBaseCmd() []string {
+	// Use $CC if set, since that's what the build uses.
+	if ret := strings.Fields(os.Getenv("CC")); len(ret) > 0 {
+		return ret
+	}
+	// Try $GCC if set, since that's what we used to use.
+	if ret := strings.Fields(os.Getenv("GCC")); len(ret) > 0 {
+		return ret
+	}
+	return strings.Fields(defaultCC)
+}
+
+// gccMachine returns the gcc -m flag to use, either "-m32", "-m64" or "-marm".
+func (p *Package) gccMachine() []string {
+	switch goarch {
+	case "amd64":
+		return []string{"-m64"}
+	case "386":
+		return []string{"-m32"}
+	case "arm":
+		return []string{"-marm"} // not thumb
+	}
+	return nil
+}
+
+func gccTmp() string {
+	return *objDir + "_cgo_.o"
+}
+
+// gccCmd returns the gcc command line to use for compiling
+// the input.
+func (p *Package) gccCmd() []string {
+	c := append(p.gccBaseCmd(),
+		"-w",          // no warnings
+		"-Wno-error",  // warnings are not errors
+		"-o"+gccTmp(), // write object to tmp
+		"-gdwarf-2",   // generate DWARF v2 debugging symbols
+		"-c",          // do not link
+		"-xc",         // input language is C
+	)
+	if strings.Contains(c[0], "clang") {
+		c = append(c,
+			"-ferror-limit=0",
+			// Apple clang version 1.7 (tags/Apple/clang-77) (based on LLVM 2.9svn)
+			// doesn't have -Wno-unneeded-internal-declaration, so we need yet another
+			// flag to disable the warning. Yes, really good diagnostics, clang.
+			"-Wno-unknown-warning-option",
+			"-Wno-unneeded-internal-declaration",
+			"-Wno-unused-function",
+			"-Qunused-arguments",
+			// Clang embeds prototypes for some builtin functions,
+			// like malloc and calloc, but all size_t parameters are
+			// incorrectly typed unsigned long. We work around that
+			// by disabling the builtin functions (this is safe as
+			// it won't affect the actual compilation of the C code).
+			// See: http://golang.org/issue/6506.
+			"-fno-builtin",
+		)
+	}
+
+	c = append(c, p.GccOptions...)
+	c = append(c, p.gccMachine()...)
+	c = append(c, "-") //read input from standard input
+	return c
+}
+
+// gccDebug runs gcc -gdwarf-2 over the C program stdin and
+// returns the corresponding DWARF data and, if present, debug data block.
+func (p *Package) gccDebug(stdin []byte) (*dwarf.Data, binary.ByteOrder, []byte) {
+	runGcc(stdin, p.gccCmd())
+
+	isDebugData := func(s string) bool {
+		// Some systems use leading _ to denote non-assembly symbols.
+		return s == "__cgodebug_data" || s == "___cgodebug_data"
+	}
+
+	if f, err := macho.Open(gccTmp()); err == nil {
+		defer f.Close()
+		d, err := f.DWARF()
+		if err != nil {
+			fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
+		}
+		var data []byte
+		if f.Symtab != nil {
+			for i := range f.Symtab.Syms {
+				s := &f.Symtab.Syms[i]
+				if isDebugData(s.Name) {
+					// Found it.  Now find data section.
+					if i := int(s.Sect) - 1; 0 <= i && i < len(f.Sections) {
+						sect := f.Sections[i]
+						if sect.Addr <= s.Value && s.Value < sect.Addr+sect.Size {
+							if sdat, err := sect.Data(); err == nil {
+								data = sdat[s.Value-sect.Addr:]
+							}
+						}
+					}
+				}
+			}
+		}
+		return d, f.ByteOrder, data
+	}
+
+	if f, err := elf.Open(gccTmp()); err == nil {
+		defer f.Close()
+		d, err := f.DWARF()
+		if err != nil {
+			fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
+		}
+		var data []byte
+		symtab, err := f.Symbols()
+		if err == nil {
+			for i := range symtab {
+				s := &symtab[i]
+				if isDebugData(s.Name) {
+					// Found it.  Now find data section.
+					if i := int(s.Section); 0 <= i && i < len(f.Sections) {
+						sect := f.Sections[i]
+						if sect.Addr <= s.Value && s.Value < sect.Addr+sect.Size {
+							if sdat, err := sect.Data(); err == nil {
+								data = sdat[s.Value-sect.Addr:]
+							}
+						}
+					}
+				}
+			}
+		}
+		return d, f.ByteOrder, data
+	}
+
+	if f, err := pe.Open(gccTmp()); err == nil {
+		defer f.Close()
+		d, err := f.DWARF()
+		if err != nil {
+			fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
+		}
+		var data []byte
+		for _, s := range f.Symbols {
+			if isDebugData(s.Name) {
+				if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
+					sect := f.Sections[i]
+					if s.Value < sect.Size {
+						if sdat, err := sect.Data(); err == nil {
+							data = sdat[s.Value:]
+						}
+					}
+				}
+			}
+		}
+		return d, binary.LittleEndian, data
+	}
+
+	fatalf("cannot parse gcc output %s as ELF, Mach-O, PE object", gccTmp())
+	panic("not reached")
+}
+
+// gccDefines runs gcc -E -dM -xc - over the C program stdin
+// and returns the corresponding standard output, which is the
+// #defines that gcc encountered while processing the input
+// and its included files.
+func (p *Package) gccDefines(stdin []byte) string {
+	base := append(p.gccBaseCmd(), "-E", "-dM", "-xc")
+	base = append(base, p.gccMachine()...)
+	stdout, _ := runGcc(stdin, append(append(base, p.GccOptions...), "-"))
+	return stdout
+}
+
+// gccErrors runs gcc over the C program stdin and returns
+// the errors that gcc prints.  That is, this function expects
+// gcc to fail.
+func (p *Package) gccErrors(stdin []byte) string {
+	// TODO(rsc): require failure
+	args := p.gccCmd()
+
+	if *debugGcc {
+		fmt.Fprintf(os.Stderr, "$ %s <<EOF\n", strings.Join(args, " "))
+		os.Stderr.Write(stdin)
+		fmt.Fprint(os.Stderr, "EOF\n")
+	}
+	stdout, stderr, _ := run(stdin, args)
+	if *debugGcc {
+		os.Stderr.Write(stdout)
+		os.Stderr.Write(stderr)
+	}
+	return string(stderr)
+}
+
+// runGcc runs the gcc command line args with stdin on standard input.
+// If the command exits with a non-zero exit status, runGcc prints
+// details about what was run and exits.
+// Otherwise runGcc returns the data written to standard output and standard error.
+// Note that for some of the uses we expect useful data back
+// on standard error, but for those uses gcc must still exit 0.
+func runGcc(stdin []byte, args []string) (string, string) {
+	if *debugGcc {
+		fmt.Fprintf(os.Stderr, "$ %s <<EOF\n", strings.Join(args, " "))
+		os.Stderr.Write(stdin)
+		fmt.Fprint(os.Stderr, "EOF\n")
+	}
+	stdout, stderr, ok := run(stdin, args)
+	if *debugGcc {
+		os.Stderr.Write(stdout)
+		os.Stderr.Write(stderr)
+	}
+	if !ok {
+		os.Stderr.Write(stderr)
+		os.Exit(2)
+	}
+	return string(stdout), string(stderr)
+}
+
+// A typeConv is a translator from dwarf types to Go types
+// with equivalent memory layout.
+type typeConv struct {
+	// Cache of already-translated or in-progress types.
+	m       map[dwarf.Type]*Type
+	typedef map[string]ast.Expr
+
+	// Predeclared types.
+	bool                                   ast.Expr
+	byte                                   ast.Expr // denotes padding
+	int8, int16, int32, int64              ast.Expr
+	uint8, uint16, uint32, uint64, uintptr ast.Expr
+	float32, float64                       ast.Expr
+	complex64, complex128                  ast.Expr
+	void                                   ast.Expr
+	unsafePointer                          ast.Expr
+	string                                 ast.Expr
+	goVoid                                 ast.Expr // _Ctype_void, denotes C's void
+
+	ptrSize int64
+	intSize int64
+}
+
+var tagGen int
+var typedef = make(map[string]*Type)
+var goIdent = make(map[string]*ast.Ident)
+
+func (c *typeConv) Init(ptrSize, intSize int64) {
+	c.ptrSize = ptrSize
+	c.intSize = intSize
+	c.m = make(map[dwarf.Type]*Type)
+	c.bool = c.Ident("bool")
+	c.byte = c.Ident("byte")
+	c.int8 = c.Ident("int8")
+	c.int16 = c.Ident("int16")
+	c.int32 = c.Ident("int32")
+	c.int64 = c.Ident("int64")
+	c.uint8 = c.Ident("uint8")
+	c.uint16 = c.Ident("uint16")
+	c.uint32 = c.Ident("uint32")
+	c.uint64 = c.Ident("uint64")
+	c.uintptr = c.Ident("uintptr")
+	c.float32 = c.Ident("float32")
+	c.float64 = c.Ident("float64")
+	c.complex64 = c.Ident("complex64")
+	c.complex128 = c.Ident("complex128")
+	c.unsafePointer = c.Ident("unsafe.Pointer")
+	c.void = c.Ident("void")
+	c.string = c.Ident("string")
+	c.goVoid = c.Ident("_Ctype_void")
+}
+
+// base strips away qualifiers and typedefs to get the underlying type
+func base(dt dwarf.Type) dwarf.Type {
+	for {
+		if d, ok := dt.(*dwarf.QualType); ok {
+			dt = d.Type
+			continue
+		}
+		if d, ok := dt.(*dwarf.TypedefType); ok {
+			dt = d.Type
+			continue
+		}
+		break
+	}
+	return dt
+}
+
+// Map from dwarf text names to aliases we use in package "C".
+var dwarfToName = map[string]string{
+	"long int":               "long",
+	"long unsigned int":      "ulong",
+	"unsigned int":           "uint",
+	"short unsigned int":     "ushort",
+	"short int":              "short",
+	"long long int":          "longlong",
+	"long long unsigned int": "ulonglong",
+	"signed char":            "schar",
+	"float complex":          "complexfloat",
+	"double complex":         "complexdouble",
+}
+
+const signedDelta = 64
+
+// String returns the current type representation.  Format arguments
+// are assembled within this method so that any changes in mutable
+// values are taken into account.
+func (tr *TypeRepr) String() string {
+	if len(tr.Repr) == 0 {
+		return ""
+	}
+	if len(tr.FormatArgs) == 0 {
+		return tr.Repr
+	}
+	return fmt.Sprintf(tr.Repr, tr.FormatArgs...)
+}
+
+// Empty returns true if the result of String would be "".
+func (tr *TypeRepr) Empty() bool {
+	return len(tr.Repr) == 0
+}
+
+// Set modifies the type representation.
+// If fargs are provided, repr is used as a format for fmt.Sprintf.
+// Otherwise, repr is used unprocessed as the type representation.
+func (tr *TypeRepr) Set(repr string, fargs ...interface{}) {
+	tr.Repr = repr
+	tr.FormatArgs = fargs
+}
+
+// Type returns a *Type with the same memory layout as
+// dtype when used as the type of a variable or a struct field.
+func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
+	if t, ok := c.m[dtype]; ok {
+		if t.Go == nil {
+			fatalf("%s: type conversion loop at %s", lineno(pos), dtype)
+		}
+		return t
+	}
+
+	// clang won't generate DW_AT_byte_size for pointer types,
+	// so we have to fix it here.
+	if dt, ok := base(dtype).(*dwarf.PtrType); ok && dt.ByteSize == -1 {
+		dt.ByteSize = c.ptrSize
+	}
+
+	t := new(Type)
+	t.Size = dtype.Size() // note: wrong for array of pointers, corrected below
+	t.Align = -1
+	t.C = &TypeRepr{Repr: dtype.Common().Name}
+	c.m[dtype] = t
+
+	switch dt := dtype.(type) {
+	default:
+		fatalf("%s: unexpected type: %s", lineno(pos), dtype)
+
+	case *dwarf.AddrType:
+		if t.Size != c.ptrSize {
+			fatalf("%s: unexpected: %d-byte address type - %s", lineno(pos), t.Size, dtype)
+		}
+		t.Go = c.uintptr
+		t.Align = t.Size
+
+	case *dwarf.ArrayType:
+		if dt.StrideBitSize > 0 {
+			// Cannot represent bit-sized elements in Go.
+			t.Go = c.Opaque(t.Size)
+			break
+		}
+		gt := &ast.ArrayType{
+			Len: c.intExpr(dt.Count),
+		}
+		t.Go = gt // publish before recursive call
+		sub := c.Type(dt.Type, pos)
+		t.Align = sub.Align
+		gt.Elt = sub.Go
+		t.C.Set("__typeof__(%s[%d])", sub.C, dt.Count)
+
+	case *dwarf.BoolType:
+		t.Go = c.bool
+		t.Align = 1
+
+	case *dwarf.CharType:
+		if t.Size != 1 {
+			fatalf("%s: unexpected: %d-byte char type - %s", lineno(pos), t.Size, dtype)
+		}
+		t.Go = c.int8
+		t.Align = 1
+
+	case *dwarf.EnumType:
+		if t.Align = t.Size; t.Align >= c.ptrSize {
+			t.Align = c.ptrSize
+		}
+		t.C.Set("enum " + dt.EnumName)
+		signed := 0
+		t.EnumValues = make(map[string]int64)
+		for _, ev := range dt.Val {
+			t.EnumValues[ev.Name] = ev.Val
+			if ev.Val < 0 {
+				signed = signedDelta
+			}
+		}
+		switch t.Size + int64(signed) {
+		default:
+			fatalf("%s: unexpected: %d-byte enum type - %s", lineno(pos), t.Size, dtype)
+		case 1:
+			t.Go = c.uint8
+		case 2:
+			t.Go = c.uint16
+		case 4:
+			t.Go = c.uint32
+		case 8:
+			t.Go = c.uint64
+		case 1 + signedDelta:
+			t.Go = c.int8
+		case 2 + signedDelta:
+			t.Go = c.int16
+		case 4 + signedDelta:
+			t.Go = c.int32
+		case 8 + signedDelta:
+			t.Go = c.int64
+		}
+
+	case *dwarf.FloatType:
+		switch t.Size {
+		default:
+			fatalf("%s: unexpected: %d-byte float type - %s", lineno(pos), t.Size, dtype)
+		case 4:
+			t.Go = c.float32
+		case 8:
+			t.Go = c.float64
+		}
+		if t.Align = t.Size; t.Align >= c.ptrSize {
+			t.Align = c.ptrSize
+		}
+
+	case *dwarf.ComplexType:
+		switch t.Size {
+		default:
+			fatalf("%s: unexpected: %d-byte complex type - %s", lineno(pos), t.Size, dtype)
+		case 8:
+			t.Go = c.complex64
+		case 16:
+			t.Go = c.complex128
+		}
+		if t.Align = t.Size; t.Align >= c.ptrSize {
+			t.Align = c.ptrSize
+		}
+
+	case *dwarf.FuncType:
+		// No attempt at translation: would enable calls
+		// directly between worlds, but we need to moderate those.
+		t.Go = c.uintptr
+		t.Align = c.ptrSize
+
+	case *dwarf.IntType:
+		if dt.BitSize > 0 {
+			fatalf("%s: unexpected: %d-bit int type - %s", lineno(pos), dt.BitSize, dtype)
+		}
+		switch t.Size {
+		default:
+			fatalf("%s: unexpected: %d-byte int type - %s", lineno(pos), t.Size, dtype)
+		case 1:
+			t.Go = c.int8
+		case 2:
+			t.Go = c.int16
+		case 4:
+			t.Go = c.int32
+		case 8:
+			t.Go = c.int64
+		}
+		if t.Align = t.Size; t.Align >= c.ptrSize {
+			t.Align = c.ptrSize
+		}
+
+	case *dwarf.PtrType:
+		t.Align = c.ptrSize
+
+		// Translate void* as unsafe.Pointer
+		if _, ok := base(dt.Type).(*dwarf.VoidType); ok {
+			t.Go = c.unsafePointer
+			t.C.Set("void*")
+			break
+		}
+
+		gt := &ast.StarExpr{}
+		t.Go = gt // publish before recursive call
+		sub := c.Type(dt.Type, pos)
+		gt.X = sub.Go
+		t.C.Set("%s*", sub.C)
+
+	case *dwarf.QualType:
+		// Ignore qualifier.
+		t = c.Type(dt.Type, pos)
+		c.m[dtype] = t
+		return t
+
+	case *dwarf.StructType:
+		if dt.ByteSize < 0 { // opaque struct
+			break
+		}
+		// Convert to Go struct, being careful about alignment.
+		// Have to give it a name to simulate C "struct foo" references.
+		tag := dt.StructName
+		if tag == "" {
+			tag = "__" + strconv.Itoa(tagGen)
+			tagGen++
+		} else if t.C.Empty() {
+			t.C.Set(dt.Kind + " " + tag)
+		}
+		name := c.Ident("_Ctype_" + dt.Kind + "_" + tag)
+		t.Go = name // publish before recursive calls
+		goIdent[name.Name] = name
+		switch dt.Kind {
+		case "class", "union":
+			t.Go = c.Opaque(t.Size)
+			if t.C.Empty() {
+				t.C.Set("__typeof__(unsigned char[%d])", t.Size)
+			}
+			t.Align = 1 // TODO: should probably base this on field alignment.
+			typedef[name.Name] = t
+		case "struct":
+			g, csyntax, align := c.Struct(dt, pos)
+			if t.C.Empty() {
+				t.C.Set(csyntax)
+			}
+			t.Align = align
+			tt := *t
+			if tag != "" {
+				tt.C = &TypeRepr{"struct %s", []interface{}{tag}}
+			}
+			tt.Go = g
+			typedef[name.Name] = &tt
+		}
+
+	case *dwarf.TypedefType:
+		// Record typedef for printing.
+		if dt.Name == "_GoString_" {
+			// Special C name for Go string type.
+			// Knows string layout used by compilers: pointer plus length,
+			// which rounds up to 2 pointers after alignment.
+			t.Go = c.string
+			t.Size = c.ptrSize * 2
+			t.Align = c.ptrSize
+			break
+		}
+		if dt.Name == "_GoBytes_" {
+			// Special C name for Go []byte type.
+			// Knows slice layout used by compilers: pointer, length, cap.
+			t.Go = c.Ident("[]byte")
+			t.Size = c.ptrSize + 4 + 4
+			t.Align = c.ptrSize
+			break
+		}
+		name := c.Ident("_Ctype_" + dt.Name)
+		goIdent[name.Name] = name
+		t.Go = name // publish before recursive call
+		sub := c.Type(dt.Type, pos)
+		t.Size = sub.Size
+		t.Align = sub.Align
+		if _, ok := typedef[name.Name]; !ok {
+			tt := *t
+			tt.Go = sub.Go
+			typedef[name.Name] = &tt
+		}
+		if *godefs || *cdefs {
+			t.Go = sub.Go
+		}
+
+	case *dwarf.UcharType:
+		if t.Size != 1 {
+			fatalf("%s: unexpected: %d-byte uchar type - %s", lineno(pos), t.Size, dtype)
+		}
+		t.Go = c.uint8
+		t.Align = 1
+
+	case *dwarf.UintType:
+		if dt.BitSize > 0 {
+			fatalf("%s: unexpected: %d-bit uint type - %s", lineno(pos), dt.BitSize, dtype)
+		}
+		switch t.Size {
+		default:
+			fatalf("%s: unexpected: %d-byte uint type - %s", lineno(pos), t.Size, dtype)
+		case 1:
+			t.Go = c.uint8
+		case 2:
+			t.Go = c.uint16
+		case 4:
+			t.Go = c.uint32
+		case 8:
+			t.Go = c.uint64
+		}
+		if t.Align = t.Size; t.Align >= c.ptrSize {
+			t.Align = c.ptrSize
+		}
+
+	case *dwarf.VoidType:
+		t.Go = c.goVoid
+		t.C.Set("void")
+		t.Align = 1
+	}
+
+	switch dtype.(type) {
+	case *dwarf.AddrType, *dwarf.BoolType, *dwarf.CharType, *dwarf.IntType, *dwarf.FloatType, *dwarf.UcharType, *dwarf.UintType:
+		s := dtype.Common().Name
+		if s != "" {
+			if ss, ok := dwarfToName[s]; ok {
+				s = ss
+			}
+			s = strings.Join(strings.Split(s, " "), "") // strip spaces
+			name := c.Ident("_Ctype_" + s)
+			tt := *t
+			typedef[name.Name] = &tt
+			if !*godefs && !*cdefs {
+				t.Go = name
+			}
+		}
+	}
+
+	if t.Size <= 0 {
+		// Clang does not record the size of a pointer in its DWARF entry,
+		// so if dtype is an array, the call to dtype.Size at the top of the function
+		// computed the size as the array length * 0 = 0.
+		// The type switch called Type (this function) recursively on the pointer
+		// entry, and the code near the top of the function updated the size to
+		// be correct, so calling dtype.Size again will produce the correct value.
+		t.Size = dtype.Size()
+		if t.Size < 0 {
+			// Unsized types are [0]byte
+			t.Size = 0
+			t.Go = c.Opaque(0)
+			if t.C.Empty() {
+				t.C.Set("void")
+			}
+			return t
+		}
+	}
+
+	if t.C.Empty() {
+		fatalf("%s: internal error: did not create C name for %s", lineno(pos), dtype)
+	}
+
+	return t
+}
+
+// FuncArg returns a Go type with the same memory layout as
+// dtype when used as the type of a C function argument.
+func (c *typeConv) FuncArg(dtype dwarf.Type, pos token.Pos) *Type {
+	t := c.Type(dtype, pos)
+	switch dt := dtype.(type) {
+	case *dwarf.ArrayType:
+		// Arrays are passed implicitly as pointers in C.
+		// In Go, we must be explicit.
+		tr := &TypeRepr{}
+		tr.Set("%s*", t.C)
+		return &Type{
+			Size:  c.ptrSize,
+			Align: c.ptrSize,
+			Go:    &ast.StarExpr{X: t.Go},
+			C:     tr,
+		}
+	case *dwarf.TypedefType:
+		// C has much more relaxed rules than Go for
+		// implicit type conversions.  When the parameter
+		// is type T defined as *X, simulate a little of the
+		// laxness of C by making the argument *X instead of T.
+		if ptr, ok := base(dt.Type).(*dwarf.PtrType); ok {
+			// Unless the typedef happens to point to void* since
+			// Go has special rules around using unsafe.Pointer.
+			if _, void := base(ptr.Type).(*dwarf.VoidType); void {
+				break
+			}
+
+			t = c.Type(ptr, pos)
+			if t == nil {
+				return nil
+			}
+
+			// Remember the C spelling, in case the struct
+			// has __attribute__((unavailable)) on it.  See issue 2888.
+			t.Typedef = dt.Name
+		}
+	}
+	return t
+}
+
+// FuncType returns the Go type analogous to dtype.
+// There is no guarantee about matching memory layout.
+func (c *typeConv) FuncType(dtype *dwarf.FuncType, pos token.Pos) *FuncType {
+	p := make([]*Type, len(dtype.ParamType))
+	gp := make([]*ast.Field, len(dtype.ParamType))
+	for i, f := range dtype.ParamType {
+		// gcc's DWARF generator outputs a single DotDotDotType parameter for
+		// function pointers that specify no parameters (e.g. void
+		// (*__cgo_0)()).  Treat this special case as void.  This case is
+		// invalid according to ISO C anyway (i.e. void (*__cgo_1)(...) is not
+		// legal).
+		if _, ok := f.(*dwarf.DotDotDotType); ok && i == 0 {
+			p, gp = nil, nil
+			break
+		}
+		p[i] = c.FuncArg(f, pos)
+		gp[i] = &ast.Field{Type: p[i].Go}
+	}
+	var r *Type
+	var gr []*ast.Field
+	if _, ok := dtype.ReturnType.(*dwarf.VoidType); ok {
+		gr = []*ast.Field{{Type: c.goVoid}}
+	} else if dtype.ReturnType != nil {
+		r = c.Type(dtype.ReturnType, pos)
+		gr = []*ast.Field{{Type: r.Go}}
+	}
+	return &FuncType{
+		Params: p,
+		Result: r,
+		Go: &ast.FuncType{
+			Params:  &ast.FieldList{List: gp},
+			Results: &ast.FieldList{List: gr},
+		},
+	}
+}
+
+// Identifier
+func (c *typeConv) Ident(s string) *ast.Ident {
+	return ast.NewIdent(s)
+}
+
+// Opaque type of n bytes.
+func (c *typeConv) Opaque(n int64) ast.Expr {
+	return &ast.ArrayType{
+		Len: c.intExpr(n),
+		Elt: c.byte,
+	}
+}
+
+// Expr for integer n.
+func (c *typeConv) intExpr(n int64) ast.Expr {
+	return &ast.BasicLit{
+		Kind:  token.INT,
+		Value: strconv.FormatInt(n, 10),
+	}
+}
+
+// Add padding of given size to fld.
+func (c *typeConv) pad(fld []*ast.Field, size int64) []*ast.Field {
+	n := len(fld)
+	fld = fld[0 : n+1]
+	fld[n] = &ast.Field{Names: []*ast.Ident{c.Ident("_")}, Type: c.Opaque(size)}
+	return fld
+}
+
+// Struct conversion: return Go and (6g) C syntax for type.
+func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.StructType, csyntax string, align int64) {
+	var buf bytes.Buffer
+	buf.WriteString("struct {")
+	fld := make([]*ast.Field, 0, 2*len(dt.Field)+1) // enough for padding around every field
+	off := int64(0)
+
+	// Rename struct fields that happen to be named Go keywords into
+	// _{keyword}.  Create a map from C ident -> Go ident.  The Go ident will
+	// be mangled.  Any existing identifier that already has the same name on
+	// the C-side will cause the Go-mangled version to be prefixed with _.
+	// (e.g. in a struct with fields '_type' and 'type', the latter would be
+	// rendered as '__type' in Go).
+	ident := make(map[string]string)
+	used := make(map[string]bool)
+	for _, f := range dt.Field {
+		ident[f.Name] = f.Name
+		used[f.Name] = true
+	}
+
+	if !*godefs && !*cdefs {
+		for cid, goid := range ident {
+			if token.Lookup(goid).IsKeyword() {
+				// Avoid keyword
+				goid = "_" + goid
+
+				// Also avoid existing fields
+				for _, exist := used[goid]; exist; _, exist = used[goid] {
+					goid = "_" + goid
+				}
+
+				used[goid] = true
+				ident[cid] = goid
+			}
+		}
+	}
+
+	anon := 0
+	for _, f := range dt.Field {
+		if f.ByteOffset > off {
+			fld = c.pad(fld, f.ByteOffset-off)
+			off = f.ByteOffset
+		}
+		t := c.Type(f.Type, pos)
+		tgo := t.Go
+		size := t.Size
+
+		if f.BitSize > 0 {
+			if f.BitSize%8 != 0 {
+				continue
+			}
+			size = f.BitSize / 8
+			name := tgo.(*ast.Ident).String()
+			if strings.HasPrefix(name, "int") {
+				name = "int"
+			} else {
+				name = "uint"
+			}
+			tgo = ast.NewIdent(name + fmt.Sprint(f.BitSize))
+		}
+
+		n := len(fld)
+		fld = fld[0 : n+1]
+		name := f.Name
+		if name == "" {
+			name = fmt.Sprintf("anon%d", anon)
+			anon++
+			ident[name] = name
+		}
+		fld[n] = &ast.Field{Names: []*ast.Ident{c.Ident(ident[name])}, Type: tgo}
+		off += size
+		buf.WriteString(t.C.String())
+		buf.WriteString(" ")
+		buf.WriteString(name)
+		buf.WriteString("; ")
+		if t.Align > align {
+			align = t.Align
+		}
+	}
+	if off < dt.ByteSize {
+		fld = c.pad(fld, dt.ByteSize-off)
+		off = dt.ByteSize
+	}
+	if off != dt.ByteSize {
+		fatalf("%s: struct size calculation error off=%d bytesize=%d", lineno(pos), off, dt.ByteSize)
+	}
+	buf.WriteString("}")
+	csyntax = buf.String()
+
+	if *godefs || *cdefs {
+		godefsFields(fld)
+	}
+	expr = &ast.StructType{Fields: &ast.FieldList{List: fld}}
+	return
+}
+
+func upper(s string) string {
+	if s == "" {
+		return ""
+	}
+	r, size := utf8.DecodeRuneInString(s)
+	if r == '_' {
+		return "X" + s
+	}
+	return string(unicode.ToUpper(r)) + s[size:]
+}
+
+// godefsFields rewrites field names for use in Go or C definitions.
+// It strips leading common prefixes (like tv_ in tv_sec, tv_usec)
+// converts names to upper case, and rewrites _ into Pad_godefs_n,
+// so that all fields are exported.
+func godefsFields(fld []*ast.Field) {
+	prefix := fieldPrefix(fld)
+	npad := 0
+	for _, f := range fld {
+		for _, n := range f.Names {
+			if n.Name != prefix {
+				n.Name = strings.TrimPrefix(n.Name, prefix)
+			}
+			if n.Name == "_" {
+				// Use exported name instead.
+				n.Name = "Pad_cgo_" + strconv.Itoa(npad)
+				npad++
+			}
+			if !*cdefs {
+				n.Name = upper(n.Name)
+			}
+		}
+		p := &f.Type
+		t := *p
+		if star, ok := t.(*ast.StarExpr); ok {
+			star = &ast.StarExpr{X: star.X}
+			*p = star
+			p = &star.X
+			t = *p
+		}
+		if id, ok := t.(*ast.Ident); ok {
+			if id.Name == "unsafe.Pointer" {
+				*p = ast.NewIdent("*byte")
+			}
+		}
+	}
+}
+
+// fieldPrefix returns the prefix that should be removed from all the
+// field names when generating the C or Go code.  For generated
+// C, we leave the names as is (tv_sec, tv_usec), since that's what
+// people are used to seeing in C.  For generated Go code, such as
+// package syscall's data structures, we drop a common prefix
+// (so sec, usec, which will get turned into Sec, Usec for exporting).
+func fieldPrefix(fld []*ast.Field) string {
+	if *cdefs {
+		return ""
+	}
+	prefix := ""
+	for _, f := range fld {
+		for _, n := range f.Names {
+			// Ignore field names that don't have the prefix we're
+			// looking for.  It is common in C headers to have fields
+			// named, say, _pad in an otherwise prefixed header.
+			// If the struct has 3 fields tv_sec, tv_usec, _pad1, then we
+			// still want to remove the tv_ prefix.
+			// The check for "orig_" here handles orig_eax in the
+			// x86 ptrace register sets, which otherwise have all fields
+			// with reg_ prefixes.
+			if strings.HasPrefix(n.Name, "orig_") || strings.HasPrefix(n.Name, "_") {
+				continue
+			}
+			i := strings.Index(n.Name, "_")
+			if i < 0 {
+				continue
+			}
+			if prefix == "" {
+				prefix = n.Name[:i+1]
+			} else if prefix != n.Name[:i+1] {
+				return ""
+			}
+		}
+	}
+	return prefix
+}
 
=== added directory '.pc/build-cgo.diff/src/cmd/go'
=== added file '.pc/build-cgo.diff/src/cmd/go/tool.go'
--- .pc/build-cgo.diff/src/cmd/go/tool.go	1970-01-01 00:00:00 +0000
+++ .pc/build-cgo.diff/src/cmd/go/tool.go	2014-08-14 02:29:21 +0000
@@ -0,0 +1,156 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	"go/build"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+)
+
+var cmdTool = &Command{
+	Run:       runTool,
+	UsageLine: "tool [-n] command [args...]",
+	Short:     "run specified go tool",
+	Long: `
+Tool runs the go tool command identified by the arguments.
+With no arguments it prints the list of known tools.
+
+The -n flag causes tool to print the command that would be
+executed but not execute it.
+
+For more about each tool command, see 'go tool command -h'.
+`,
+}
+
+var (
+	toolGOOS      = runtime.GOOS
+	toolGOARCH    = runtime.GOARCH
+	toolIsWindows = toolGOOS == "windows"
+	toolDir       = build.ToolDir
+
+	toolN bool
+)
+
+func init() {
+	cmdTool.Flag.BoolVar(&toolN, "n", false, "")
+}
+
+const toolWindowsExtension = ".exe"
+
+func tool(toolName string) string {
+	toolPath := filepath.Join(toolDir, toolName)
+	if toolIsWindows && toolName != "pprof" {
+		toolPath += toolWindowsExtension
+	}
+	// Give a nice message if there is no tool with that name.
+	if _, err := os.Stat(toolPath); err != nil {
+		if isInGoToolsRepo(toolName) {
+			fmt.Fprintf(os.Stderr, "go tool: no such tool %q; to install:\n\tgo get code.google.com/p/go.tools/cmd/%s\n", toolName, toolName)
+		} else {
+			fmt.Fprintf(os.Stderr, "go tool: no such tool %q\n", toolName)
+		}
+		setExitStatus(3)
+		exit()
+	}
+	return toolPath
+}
+
+func isInGoToolsRepo(toolName string) bool {
+	switch toolName {
+	case "cover", "vet":
+		return true
+	}
+	return false
+}
+
+func runTool(cmd *Command, args []string) {
+	if len(args) == 0 {
+		listTools()
+		return
+	}
+	toolName := args[0]
+	// The tool name must be lower-case letters, numbers or underscores.
+	for _, c := range toolName {
+		switch {
+		case 'a' <= c && c <= 'z', '0' <= c && c <= '9', c == '_':
+		default:
+			fmt.Fprintf(os.Stderr, "go tool: bad tool name %q\n", toolName)
+			setExitStatus(2)
+			return
+		}
+	}
+	toolPath := tool(toolName)
+	if toolPath == "" {
+		return
+	}
+	if toolIsWindows && toolName == "pprof" {
+		args = append([]string{"perl", toolPath}, args[1:]...)
+		var err error
+		toolPath, err = exec.LookPath("perl")
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "go tool: perl not found\n")
+			setExitStatus(3)
+			return
+		}
+	}
+	if toolN {
+		fmt.Printf("%s %s\n", toolPath, strings.Join(args[1:], " "))
+		return
+	}
+	toolCmd := &exec.Cmd{
+		Path:   toolPath,
+		Args:   args,
+		Stdin:  os.Stdin,
+		Stdout: os.Stdout,
+		Stderr: os.Stderr,
+	}
+	err := toolCmd.Run()
+	if err != nil {
+		// Only print about the exit status if the command
+		// didn't even run (not an ExitError) or it didn't exit cleanly
+		// or we're printing command lines too (-x mode).
+		// Assume if command exited cleanly (even with non-zero status)
+		// it printed any messages it wanted to print.
+		if e, ok := err.(*exec.ExitError); !ok || !e.Exited() || buildX {
+			fmt.Fprintf(os.Stderr, "go tool %s: %s\n", toolName, err)
+		}
+		setExitStatus(1)
+		return
+	}
+}
+
+// listTools prints a list of the available tools in the tools directory.
+func listTools() {
+	f, err := os.Open(toolDir)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: no tool directory: %s\n", err)
+		setExitStatus(2)
+		return
+	}
+	defer f.Close()
+	names, err := f.Readdirnames(-1)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "go tool: can't read directory: %s\n", err)
+		setExitStatus(2)
+		return
+	}
+
+	sort.Strings(names)
+	for _, name := range names {
+		// Unify presentation by going to lower case.
+		name = strings.ToLower(name)
+		// If it's windows, don't show the .exe suffix.
+		if toolIsWindows && strings.HasSuffix(name, toolWindowsExtension) {
+			name = name[:len(name)-len(toolWindowsExtension)]
+		}
+		fmt.Println(name)
+	}
+}
 
=== modified file 'debian/changelog'
--- debian/changelog	2014-03-26 10:50:18 +0000
+++ debian/changelog	2014-08-14 02:29:21 +0000
@@ -1,3 +1,9 @@
+gccgo-go (1.2.1-0ubuntu2) UNRELEASED; urgency=medium
+
+  * Build and install cgo too.
+
+ -- Michael Hudson-Doyle <[e-mail]>  Thu, 14 Aug 2014 14:01:51 +1200
+
 gccgo-go (1.2.1-0ubuntu1) trusty; urgency=medium
 
   * New upstream point release.
 
=== modified file 'debian/install'
--- debian/install	2014-01-28 12:32:46 +0000
+++ debian/install	2014-08-14 02:29:21 +0000
@@ -1,1 +1,2 @@
 src/cmd/go/gccgo-go /usr/bin
+src/cmd/cgo/cgo /usr/lib/gccgo/tool
 \ No newline at end of file
 
=== modified file 'debian/lintian-overrides'
--- debian/lintian-overrides	2014-01-27 09:18:55 +0000
+++ debian/lintian-overrides	2014-08-14 02:29:21 +0000
@@ -1,2 +1,3 @@
 # go binaries should never be stripped
 gccgo-go: unstripped-binary-or-object usr/bin/gccgo-go
+gccgo-go: unstripped-binary-or-object usr/lib/gccgo/tool/cgo
 
=== added file 'debian/patches/build-cgo.diff'
--- debian/patches/build-cgo.diff	1970-01-01 00:00:00 +0000
+++ debian/patches/build-cgo.diff	2014-08-14 02:29:21 +0000
@@ -0,0 +1,49 @@
+=== added file 'src/cmd/cgo/Makefile'
+Index: gccgo-go/src/cmd/cgo/Makefile
+===================================================================
+--- /dev/null	1970-01-01 00:00:00.000000000 +0000
++++ gccgo-go/src/cmd/cgo/Makefile	2014-08-14 14:13:14.620783230 +1200
+@@ -0,0 +1,16 @@
++TARG=cgo
++GOFILES=\
++	ast.go\
++	doc.go\
++	gcc.go\
++	godefs.go\
++	main.go\
++	out.go\
++	util.go
++
++build:
++	gccgo -o _$(TARG)_ -c $(GOFLAGS) $(GOFILES)
++	gccgo -o $(TARG) _$(TARG)_ $(LDFLAGS)
++
++clean:
++	rm -f _$(TARG)_ $(TARG)
+Index: gccgo-go/src/cmd/go/tool.go
+===================================================================
+--- gccgo-go.orig/src/cmd/go/tool.go	2014-08-14 14:11:25.772787121 +1200
++++ gccgo-go/src/cmd/go/tool.go	2014-08-14 14:20:57.504766684 +1200
+@@ -41,6 +41,9 @@
+ 
+ func init() {
+ 	cmdTool.Flag.BoolVar(&toolN, "n", false, "")
++	if (runtime.Compiler == "gccgo") {
++		toolDir = filepath.Join(runtime.GOROOT(), "lib/gccgo/tool")
++	}
+ }
+ 
+ const toolWindowsExtension = ".exe"
+Index: gccgo-go/src/cmd/cgo/gcc.go
+===================================================================
+--- gccgo-go.orig/src/cmd/cgo/gcc.go	2014-08-12 15:34:03.612461000 +1200
++++ gccgo-go/src/cmd/cgo/gcc.go	2014-08-14 14:14:30.380780522 +1200
+@@ -718,7 +718,7 @@
+ 	if ret := strings.Fields(os.Getenv("GCC")); len(ret) > 0 {
+ 		return ret
+ 	}
+-	return strings.Fields(defaultCC)
++	return strings.Fields("gcc")
+ }
+ 
+ // gccMachine returns the gcc -m flag to use, either "-m32", "-m64" or "-marm".
 
=== modified file 'debian/patches/series'
--- debian/patches/series	2014-03-26 10:50:18 +0000
+++ debian/patches/series	2014-08-14 02:29:21 +0000
@@ -5,3 +5,4 @@
 issue28050043_60001_70001.diff
 issue61970044_80001.diff
 issue80300043_60001.diff
+build-cgo.diff
 
=== modified file 'debian/rules'
--- debian/rules	2014-02-15 22:18:45 +0000
+++ debian/rules	2014-08-14 02:29:21 +0000
@@ -10,6 +10,7 @@
 
 override_dh_auto_clean:
 	dh_auto_clean -D src/cmd/go
+	dh_auto_clean -D src/cmd/cgo
 
 override_dh_strip:
 	# strip disabled as golang upstream doesn't support it and it makes go
@@ -20,3 +21,4 @@
 
 override_dh_auto_build:
 	dh_auto_build -D src/cmd/go
+	dh_auto_build -D src/cmd/cgo
 
=== added file 'src/cmd/cgo/Makefile'
--- src/cmd/cgo/Makefile	1970-01-01 00:00:00 +0000
+++ src/cmd/cgo/Makefile	2014-08-14 02:29:21 +0000
@@ -0,0 +1,16 @@
+TARG=cgo
+GOFILES=\
+	ast.go\
+	doc.go\
+	gcc.go\
+	godefs.go\
+	main.go\
+	out.go\
+	util.go
+
+build:
+	gccgo -o _$(TARG)_ -c $(GOFLAGS) $(GOFILES)
+	gccgo -o $(TARG) _$(TARG)_ $(LDFLAGS)
+
+clean:
+	rm -f _$(TARG)_ $(TARG)
 
=== modified file 'src/cmd/cgo/gcc.go'
--- src/cmd/cgo/gcc.go	2014-01-27 09:18:55 +0000
+++ src/cmd/cgo/gcc.go	2014-08-14 02:29:21 +0000
@@ -718,7 +718,7 @@
 	if ret := strings.Fields(os.Getenv("GCC")); len(ret) > 0 {
 		return ret
 	}
-	return strings.Fields(defaultCC)
+	return strings.Fields("gcc")
 }
 
 // gccMachine returns the gcc -m flag to use, either "-m32", "-m64" or "-marm".
 
=== modified file 'src/cmd/go/tool.go'
--- src/cmd/go/tool.go	2014-01-27 09:18:55 +0000
+++ src/cmd/go/tool.go	2014-08-14 02:29:21 +0000
@@ -41,6 +41,9 @@
 
 func init() {
 	cmdTool.Flag.BoolVar(&toolN, "n", false, "")
+	if (runtime.Compiler == "gccgo") {
+		toolDir = filepath.Join(runtime.GOROOT(), "lib/gccgo/tool")
+	}
 }
 
 const toolWindowsExtension = ".exe"