libgo: Update to weekly.2011-11-02.

From-SVN: r181964

9 files changed, 78 insertions, 86 deletions

diff --git a/libgo/go/debug/dwarf/buf.go b/libgo/go/debug/dwarf/buf.go
index 2d29ceb..6b4af7d 100644
--- a/libgo/go/debug/dwarf/buf.go
+++ b/libgo/go/debug/dwarf/buf.go
@@ -8,7 +8,6 @@ package dwarf
 
 import (
 	"encoding/binary"
-	"os"
 	"strconv"
 )
 
@@ -20,7 +19,7 @@ type buf struct {
 	off      Offset
 	data     []byte
 	addrsize int
-	err      os.Error
+	err      error
 }
 
 func makeBuf(d *Data, name string, off Offset, data []byte, addrsize int) buf {
@@ -146,9 +145,9 @@ func (b *buf) error(s string) {
 type DecodeError struct {
 	Name   string
 	Offset Offset
-	Error  string
+	Err    string
 }
 
-func (e DecodeError) String() string {
-	return "decoding dwarf section " + e.Name + " at offset 0x" + strconv.Itob64(int64(e.Offset), 16) + ": " + e.Error
+func (e DecodeError) Error() string {
+	return "decoding dwarf section " + e.Name + " at offset 0x" + strconv.Itob64(int64(e.Offset), 16) + ": " + e.Err
 }
diff --git a/libgo/go/debug/dwarf/entry.go b/libgo/go/debug/dwarf/entry.go
index 549e5c2..2885d8f 100644
--- a/libgo/go/debug/dwarf/entry.go
+++ b/libgo/go/debug/dwarf/entry.go
@@ -10,7 +10,7 @@
 
 package dwarf
 
-import "os"
+import "errors"
 
 // a single entry's description: a sequence of attributes
 type abbrev struct {
@@ -29,7 +29,7 @@ type abbrevTable map[uint32]abbrev
 
 // ParseAbbrev returns the abbreviation table that starts at byte off
 // in the .debug_abbrev section.
-func (d *Data) parseAbbrev(off uint32) (abbrevTable, os.Error) {
+func (d *Data) parseAbbrev(off uint32) (abbrevTable, error) {
 	if m, ok := d.abbrevCache[off]; ok {
 		return m, nil
 	}
@@ -232,7 +232,7 @@ func (b *buf) entry(atab abbrevTable, ubase Offset) *Entry {
 type Reader struct {
 	b            buf
 	d            *Data
-	err          os.Error
+	err          error
 	unit         int
 	lastChildren bool   // .Children of last entry returned by Next
 	lastSibling  Offset // .Val(AttrSibling) of last entry returned by Next
@@ -273,7 +273,7 @@ func (r *Reader) Seek(off Offset) {
 			return
 		}
 	}
-	r.err = os.NewError("offset out of range")
+	r.err = errors.New("offset out of range")
 }
 
 // maybeNextUnit advances to the next unit if this one is finished.
@@ -289,7 +289,7 @@ func (r *Reader) maybeNextUnit() {
 // It returns nil, nil when it reaches the end of the section.
 // It returns an error if the current offset is invalid or the data at the
 // offset cannot be decoded as a valid Entry.
-func (r *Reader) Next() (*Entry, os.Error) {
+func (r *Reader) Next() (*Entry, error) {
 	if r.err != nil {
 		return nil, r.err
 	}
diff --git a/libgo/go/debug/dwarf/open.go b/libgo/go/debug/dwarf/open.go
index d9525f7..9543297 100644
--- a/libgo/go/debug/dwarf/open.go
+++ b/libgo/go/debug/dwarf/open.go
@@ -7,10 +7,7 @@
 // http://dwarfstd.org/doc/dwarf-2.0.0.pdf
 package dwarf
 
-import (
-	"encoding/binary"
-	"os"
-)
+import "encoding/binary"
 
 // Data represents the DWARF debugging information
 // loaded from an executable file (for example, an ELF or Mach-O executable).
@@ -40,7 +37,7 @@ type Data struct {
 // The []byte arguments are the data from the corresponding debug section
 // in the object file; for example, for an ELF object, abbrev is the contents of
 // the ".debug_abbrev" section.
-func New(abbrev, aranges, frame, info, line, pubnames, ranges, str []byte) (*Data, os.Error) {
+func New(abbrev, aranges, frame, info, line, pubnames, ranges, str []byte) (*Data, error) {
 	d := &Data{
 		abbrev:      abbrev,
 		aranges:     aranges,
diff --git a/libgo/go/debug/dwarf/type.go b/libgo/go/debug/dwarf/type.go
index 9fa221b..e8ce8d5 100644
--- a/libgo/go/debug/dwarf/type.go
+++ b/libgo/go/debug/dwarf/type.go
@@ -8,10 +8,7 @@
 
 package dwarf
 
-import (
-	"os"
-	"strconv"
-)
+import "strconv"
 
 // A Type conventionally represents a pointer to any of the
 // specific Type structures (CharType, StructType, etc.).
@@ -254,7 +251,7 @@ func (t *TypedefType) String() string { return t.Name }
 
 func (t *TypedefType) Size() int64 { return t.Type.Size() }
 
-func (d *Data) Type(off Offset) (Type, os.Error) {
+func (d *Data) Type(off Offset) (Type, error) {
 	if t, ok := d.typeCache[off]; ok {
 		return t, nil
 	}
diff --git a/libgo/go/debug/dwarf/unit.go b/libgo/go/debug/dwarf/unit.go
index 02cb363..c10d75d 100644
--- a/libgo/go/debug/dwarf/unit.go
+++ b/libgo/go/debug/dwarf/unit.go
@@ -4,10 +4,7 @@
 
 package dwarf
 
-import (
-	"os"
-	"strconv"
-)
+import "strconv"
 
 // DWARF debug info is split into a sequence of compilation units.
 // Each unit has its own abbreviation table and address size.
@@ -20,7 +17,7 @@ type unit struct {
 	addrsize int
 }
 
-func (d *Data) parseUnits() ([]unit, os.Error) {
+func (d *Data) parseUnits() ([]unit, error) {
 	// Count units.
 	nunit := 0
 	b := makeBuf(d, "info", 0, d.info, 0)
diff --git a/libgo/go/debug/elf/file.go b/libgo/go/debug/elf/file.go
index a0ddb1f..184ca83 100644
--- a/libgo/go/debug/elf/file.go
+++ b/libgo/go/debug/elf/file.go
@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"debug/dwarf"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -71,7 +72,7 @@ type Section struct {
 }
 
 // Data reads and returns the contents of the ELF section.
-func (s *Section) Data() ([]byte, os.Error) {
+func (s *Section) Data() ([]byte, error) {
 	dat := make([]byte, s.sr.Size())
 	n, err := s.sr.ReadAt(dat, 0)
 	return dat[0:n], err
@@ -79,9 +80,9 @@ func (s *Section) Data() ([]byte, os.Error) {
 
 // stringTable reads and returns the string table given by the
 // specified link value.
-func (f *File) stringTable(link uint32) ([]byte, os.Error) {
+func (f *File) stringTable(link uint32) ([]byte, error) {
 	if link <= 0 || link >= uint32(len(f.Sections)) {
-		return nil, os.NewError("section has invalid string table link")
+		return nil, errors.New("section has invalid string table link")
 	}
 	return f.Sections[link].Data()
 }
@@ -136,7 +137,7 @@ type FormatError struct {
 	val interface{}
 }
 
-func (e *FormatError) String() string {
+func (e *FormatError) Error() string {
 	msg := e.msg
 	if e.val != nil {
 		msg += fmt.Sprintf(" '%v' ", e.val)
@@ -146,7 +147,7 @@ func (e *FormatError) String() string {
 }
 
 // Open opens the named file using os.Open and prepares it for use as an ELF binary.
-func Open(name string) (*File, os.Error) {
+func Open(name string) (*File, error) {
 	f, err := os.Open(name)
 	if err != nil {
 		return nil, err
@@ -163,8 +164,8 @@ func Open(name string) (*File, os.Error) {
 // Close closes the File.
 // If the File was created using NewFile directly instead of Open,
 // Close has no effect.
-func (f *File) Close() os.Error {
-	var err os.Error
+func (f *File) Close() error {
+	var err error
 	if f.closer != nil {
 		err = f.closer.Close()
 		f.closer = nil
@@ -185,7 +186,7 @@ func (f *File) SectionByType(typ SectionType) *Section {
 
 // NewFile creates a new File for accessing an ELF binary in an underlying reader.
 // The ELF binary is expected to start at position 0 in the ReaderAt.
-func NewFile(r io.ReaderAt) (*File, os.Error) {
+func NewFile(r io.ReaderAt) (*File, error) {
 	sr := io.NewSectionReader(r, 0, 1<<63-1)
 	// Read and decode ELF identifier
 	var ident [16]uint8
@@ -381,7 +382,7 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 
 // getSymbols returns a slice of Symbols from parsing the symbol table
 // with the given type, along with the associated string table.
-func (f *File) getSymbols(typ SectionType) ([]Symbol, []byte, os.Error) {
+func (f *File) getSymbols(typ SectionType) ([]Symbol, []byte, error) {
 	switch f.Class {
 	case ELFCLASS64:
 		return f.getSymbols64(typ)
@@ -390,27 +391,27 @@ func (f *File) getSymbols(typ SectionType) ([]Symbol, []byte, os.Error) {
 		return f.getSymbols32(typ)
 	}
 
-	return nil, nil, os.NewError("not implemented")
+	return nil, nil, errors.New("not implemented")
 }
 
-func (f *File) getSymbols32(typ SectionType) ([]Symbol, []byte, os.Error) {
+func (f *File) getSymbols32(typ SectionType) ([]Symbol, []byte, error) {
 	symtabSection := f.SectionByType(typ)
 	if symtabSection == nil {
-		return nil, nil, os.NewError("no symbol section")
+		return nil, nil, errors.New("no symbol section")
 	}
 
 	data, err := symtabSection.Data()
 	if err != nil {
-		return nil, nil, os.NewError("cannot load symbol section")
+		return nil, nil, errors.New("cannot load symbol section")
 	}
 	symtab := bytes.NewBuffer(data)
 	if symtab.Len()%Sym32Size != 0 {
-		return nil, nil, os.NewError("length of symbol section is not a multiple of SymSize")
+		return nil, nil, errors.New("length of symbol section is not a multiple of SymSize")
 	}
 
 	strdata, err := f.stringTable(symtabSection.Link)
 	if err != nil {
-		return nil, nil, os.NewError("cannot load string table section")
+		return nil, nil, errors.New("cannot load string table section")
 	}
 
 	// The first entry is all zeros.
@@ -436,24 +437,24 @@ func (f *File) getSymbols32(typ SectionType) ([]Symbol, []byte, os.Error) {
 	return symbols, strdata, nil
 }
 
-func (f *File) getSymbols64(typ SectionType) ([]Symbol, []byte, os.Error) {
+func (f *File) getSymbols64(typ SectionType) ([]Symbol, []byte, error) {
 	symtabSection := f.SectionByType(typ)
 	if symtabSection == nil {
-		return nil, nil, os.NewError("no symbol section")
+		return nil, nil, errors.New("no symbol section")
 	}
 
 	data, err := symtabSection.Data()
 	if err != nil {
-		return nil, nil, os.NewError("cannot load symbol section")
+		return nil, nil, errors.New("cannot load symbol section")
 	}
 	symtab := bytes.NewBuffer(data)
 	if symtab.Len()%Sym64Size != 0 {
-		return nil, nil, os.NewError("length of symbol section is not a multiple of Sym64Size")
+		return nil, nil, errors.New("length of symbol section is not a multiple of Sym64Size")
 	}
 
 	strdata, err := f.stringTable(symtabSection.Link)
 	if err != nil {
-		return nil, nil, os.NewError("cannot load string table section")
+		return nil, nil, errors.New("cannot load string table section")
 	}
 
 	// The first entry is all zeros.
@@ -506,17 +507,17 @@ func (f *File) Section(name string) *Section {
 
 // applyRelocations applies relocations to dst. rels is a relocations section
 // in RELA format.
-func (f *File) applyRelocations(dst []byte, rels []byte) os.Error {
+func (f *File) applyRelocations(dst []byte, rels []byte) error {
 	if f.Class == ELFCLASS64 && f.Machine == EM_X86_64 {
 		return f.applyRelocationsAMD64(dst, rels)
 	}
 
-	return os.NewError("not implemented")
+	return errors.New("not implemented")
 }
 
-func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) os.Error {
+func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) error {
 	if len(rels)%Sym64Size != 0 {
-		return os.NewError("length of relocation section is not a multiple of Sym64Size")
+		return errors.New("length of relocation section is not a multiple of Sym64Size")
 	}
 
 	symbols, _, err := f.getSymbols(SHT_SYMTAB)
@@ -558,7 +559,7 @@ func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) os.Error {
 	return nil
 }
 
-func (f *File) DWARF() (*dwarf.Data, os.Error) {
+func (f *File) DWARF() (*dwarf.Data, error) {
 	// There are many other DWARF sections, but these
 	// are the required ones, and the debug/dwarf package
 	// does not use the others, so don't bother loading them.
@@ -596,7 +597,7 @@ func (f *File) DWARF() (*dwarf.Data, os.Error) {
 }
 
 // Symbols returns the symbol table for f.
-func (f *File) Symbols() ([]Symbol, os.Error) {
+func (f *File) Symbols() ([]Symbol, error) {
 	sym, _, err := f.getSymbols(SHT_SYMTAB)
 	return sym, err
 }
@@ -611,7 +612,7 @@ type ImportedSymbol struct {
 // referred to by the binary f that are expected to be
 // satisfied by other libraries at dynamic load time.
 // It does not return weak symbols.
-func (f *File) ImportedSymbols() ([]ImportedSymbol, os.Error) {
+func (f *File) ImportedSymbols() ([]ImportedSymbol, error) {
 	sym, str, err := f.getSymbols(SHT_DYNSYM)
 	if err != nil {
 		return nil, err
@@ -721,7 +722,7 @@ func (f *File) gnuVersion(i int, sym *ImportedSymbol) {
 // ImportedLibraries returns the names of all libraries
 // referred to by the binary f that are expected to be
 // linked with the binary at dynamic link time.
-func (f *File) ImportedLibraries() ([]string, os.Error) {
+func (f *File) ImportedLibraries() ([]string, error) {
 	ds := f.SectionByType(SHT_DYNAMIC)
 	if ds == nil {
 		// not dynamic, so no libraries
diff --git a/libgo/go/debug/gosym/symtab.go b/libgo/go/debug/gosym/symtab.go
index dea460d..52d7d55 100644
--- a/libgo/go/debug/gosym/symtab.go
+++ b/libgo/go/debug/gosym/symtab.go
@@ -15,7 +15,6 @@ package gosym
 import (
 	"encoding/binary"
 	"fmt"
-	"os"
 	"strconv"
 	"strings"
 )
@@ -105,7 +104,7 @@ type sym struct {
 	name   []byte
 }
 
-func walksymtab(data []byte, fn func(sym) os.Error) os.Error {
+func walksymtab(data []byte, fn func(sym) error) error {
 	var s sym
 	p := data
 	for len(p) >= 6 {
@@ -149,9 +148,9 @@ func walksymtab(data []byte, fn func(sym) os.Error) os.Error {
 
 // NewTable decodes the Go symbol table in data,
 // returning an in-memory representation.
-func NewTable(symtab []byte, pcln *LineTable) (*Table, os.Error) {
+func NewTable(symtab []byte, pcln *LineTable) (*Table, error) {
 	var n int
-	err := walksymtab(symtab, func(s sym) os.Error {
+	err := walksymtab(symtab, func(s sym) error {
 		n++
 		return nil
 	})
@@ -165,7 +164,7 @@ func NewTable(symtab []byte, pcln *LineTable) (*Table, os.Error) {
 	nf := 0
 	nz := 0
 	lasttyp := uint8(0)
-	err = walksymtab(symtab, func(s sym) os.Error {
+	err = walksymtab(symtab, func(s sym) error {
 		n := len(t.Syms)
 		t.Syms = t.Syms[0 : n+1]
 		ts := &t.Syms[n]
@@ -355,7 +354,7 @@ func (t *Table) PCToLine(pc uint64) (file string, line int, fn *Func) {
 // LineToPC looks up the first program counter on the given line in
 // the named file.  Returns UnknownPathError or UnknownLineError if
 // there is an error looking up this line.
-func (t *Table) LineToPC(file string, line int) (pc uint64, fn *Func, err os.Error) {
+func (t *Table) LineToPC(file string, line int) (pc uint64, fn *Func, err error) {
 	obj, ok := t.Files[file]
 	if !ok {
 		return 0, nil, UnknownFileError(file)
@@ -466,7 +465,7 @@ pathloop:
 	return tos.path, aline - tos.start - tos.offset + 1
 }
 
-func (o *Obj) alineFromLine(path string, line int) (int, os.Error) {
+func (o *Obj) alineFromLine(path string, line int) (int, error) {
 	if line < 1 {
 		return 0, &UnknownLineError{path, line}
 	}
@@ -516,7 +515,7 @@ func (o *Obj) alineFromLine(path string, line int) (int, os.Error) {
 // the symbol table.
 type UnknownFileError string
 
-func (e UnknownFileError) String() string { return "unknown file: " + string(e) }
+func (e UnknownFileError) Error() string { return "unknown file: " + string(e) }
 
 // UnknownLineError represents a failure to map a line to a program
 // counter, either because the line is beyond the bounds of the file
@@ -526,7 +525,7 @@ type UnknownLineError struct {
 	Line int
 }
 
-func (e *UnknownLineError) String() string {
+func (e *UnknownLineError) Error() string {
 	return "no code at " + e.File + ":" + strconv.Itoa(e.Line)
 }
 
@@ -538,7 +537,7 @@ type DecodingError struct {
 	val interface{}
 }
 
-func (e *DecodingError) String() string {
+func (e *DecodingError) Error() string {
 	msg := e.msg
 	if e.val != nil {
 		msg += fmt.Sprintf(" '%v'", e.val)
diff --git a/libgo/go/debug/macho/file.go b/libgo/go/debug/macho/file.go
index 721a4c4..c7cb905 100644
--- a/libgo/go/debug/macho/file.go
+++ b/libgo/go/debug/macho/file.go
@@ -12,6 +12,7 @@ import (
 	"bytes"
 	"debug/dwarf"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -71,7 +72,7 @@ type Segment struct {
 }
 
 // Data reads and returns the contents of the segment.
-func (s *Segment) Data() ([]byte, os.Error) {
+func (s *Segment) Data() ([]byte, error) {
 	dat := make([]byte, s.sr.Size())
 	n, err := s.sr.ReadAt(dat, 0)
 	return dat[0:n], err
@@ -106,7 +107,7 @@ type Section struct {
 }
 
 // Data reads and returns the contents of the Mach-O section.
-func (s *Section) Data() ([]byte, os.Error) {
+func (s *Section) Data() ([]byte, error) {
 	dat := make([]byte, s.sr.Size())
 	n, err := s.sr.ReadAt(dat, 0)
 	return dat[0:n], err
@@ -148,7 +149,7 @@ type FormatError struct {
 	val interface{}
 }
 
-func (e *FormatError) String() string {
+func (e *FormatError) Error() string {
 	msg := e.msg
 	if e.val != nil {
 		msg += fmt.Sprintf(" '%v'", e.val)
@@ -158,7 +159,7 @@ func (e *FormatError) String() string {
 }
 
 // Open opens the named file using os.Open and prepares it for use as a Mach-O binary.
-func Open(name string) (*File, os.Error) {
+func Open(name string) (*File, error) {
 	f, err := os.Open(name)
 	if err != nil {
 		return nil, err
@@ -175,8 +176,8 @@ func Open(name string) (*File, os.Error) {
 // Close closes the File.
 // If the File was created using NewFile directly instead of Open,
 // Close has no effect.
-func (f *File) Close() os.Error {
-	var err os.Error
+func (f *File) Close() error {
+	var err error
 	if f.closer != nil {
 		err = f.closer.Close()
 		f.closer = nil
@@ -186,7 +187,7 @@ func (f *File) Close() os.Error {
 
 // NewFile creates a new File for accessing a Mach-O binary in an underlying reader.
 // The Mach-O binary is expected to start at position 0 in the ReaderAt.
-func NewFile(r io.ReaderAt) (*File, os.Error) {
+func NewFile(r io.ReaderAt) (*File, error) {
 	f := new(File)
 	sr := io.NewSectionReader(r, 0, 1<<63-1)
 
@@ -391,7 +392,7 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 	return f, nil
 }
 
-func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset int64) (*Symtab, os.Error) {
+func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset int64) (*Symtab, error) {
 	bo := f.ByteOrder
 	symtab := make([]Symbol, hdr.Nsyms)
 	b := bytes.NewBuffer(symdat)
@@ -463,7 +464,7 @@ func (f *File) Section(name string) *Section {
 }
 
 // DWARF returns the DWARF debug information for the Mach-O file.
-func (f *File) DWARF() (*dwarf.Data, os.Error) {
+func (f *File) DWARF() (*dwarf.Data, error) {
 	// There are many other DWARF sections, but these
 	// are the required ones, and the debug/dwarf package
 	// does not use the others, so don't bother loading them.
@@ -473,7 +474,7 @@ func (f *File) DWARF() (*dwarf.Data, os.Error) {
 		name = "__debug_" + name
 		s := f.Section(name)
 		if s == nil {
-			return nil, os.NewError("missing Mach-O section " + name)
+			return nil, errors.New("missing Mach-O section " + name)
 		}
 		b, err := s.Data()
 		if err != nil && uint64(len(b)) < s.Size {
@@ -489,7 +490,7 @@ func (f *File) DWARF() (*dwarf.Data, os.Error) {
 // ImportedSymbols returns the names of all symbols
 // referred to by the binary f that are expected to be
 // satisfied by other libraries at dynamic load time.
-func (f *File) ImportedSymbols() ([]string, os.Error) {
+func (f *File) ImportedSymbols() ([]string, error) {
 	if f.Dysymtab == nil || f.Symtab == nil {
 		return nil, &FormatError{0, "missing symbol table", nil}
 	}
@@ -506,7 +507,7 @@ func (f *File) ImportedSymbols() ([]string, os.Error) {
 // ImportedLibraries returns the paths of all libraries
 // referred to by the binary f that are expected to be
 // linked with the binary at dynamic link time.
-func (f *File) ImportedLibraries() ([]string, os.Error) {
+func (f *File) ImportedLibraries() ([]string, error) {
 	var all []string
 	for _, l := range f.Loads {
 		if lib, ok := l.(*Dylib); ok {
diff --git a/libgo/go/debug/pe/file.go b/libgo/go/debug/pe/file.go
index d86d916..6b98a5f 100644
--- a/libgo/go/debug/pe/file.go
+++ b/libgo/go/debug/pe/file.go
@@ -8,6 +8,7 @@ package pe
 import (
 	"debug/dwarf"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -59,7 +60,7 @@ type ImportDirectory struct {
 }
 
 // Data reads and returns the contents of the PE section.
-func (s *Section) Data() ([]byte, os.Error) {
+func (s *Section) Data() ([]byte, error) {
 	dat := make([]byte, s.sr.Size())
 	n, err := s.sr.ReadAt(dat, 0)
 	return dat[0:n], err
@@ -74,7 +75,7 @@ type FormatError struct {
 	val interface{}
 }
 
-func (e *FormatError) String() string {
+func (e *FormatError) Error() string {
 	msg := e.msg
 	if e.val != nil {
 		msg += fmt.Sprintf(" '%v'", e.val)
@@ -84,7 +85,7 @@ func (e *FormatError) String() string {
 }
 
 // Open opens the named file using os.Open and prepares it for use as a PE binary.
-func Open(name string) (*File, os.Error) {
+func Open(name string) (*File, error) {
 	f, err := os.Open(name)
 	if err != nil {
 		return nil, err
@@ -101,8 +102,8 @@ func Open(name string) (*File, os.Error) {
 // Close closes the File.
 // If the File was created using NewFile directly instead of Open,
 // Close has no effect.
-func (f *File) Close() os.Error {
-	var err os.Error
+func (f *File) Close() error {
+	var err error
 	if f.closer != nil {
 		err = f.closer.Close()
 		f.closer = nil
@@ -111,7 +112,7 @@ func (f *File) Close() os.Error {
 }
 
 // NewFile creates a new File for accessing a PE binary in an underlying reader.
-func NewFile(r io.ReaderAt) (*File, os.Error) {
+func NewFile(r io.ReaderAt) (*File, error) {
 	f := new(File)
 	sr := io.NewSectionReader(r, 0, 1<<63-1)
 
@@ -124,7 +125,7 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 		var sign [4]byte
 		r.ReadAt(sign[0:], int64(dosheader[0x3c]))
 		if !(sign[0] == 'P' && sign[1] == 'E' && sign[2] == 0 && sign[3] == 0) {
-			return nil, os.NewError("Invalid PE File Format.")
+			return nil, errors.New("Invalid PE File Format.")
 		}
 		base = int64(dosheader[0x3c]) + 4
 	} else {
@@ -135,7 +136,7 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 		return nil, err
 	}
 	if f.FileHeader.Machine != IMAGE_FILE_MACHINE_UNKNOWN && f.FileHeader.Machine != IMAGE_FILE_MACHINE_AMD64 && f.FileHeader.Machine != IMAGE_FILE_MACHINE_I386 {
-		return nil, os.NewError("Invalid PE File Format.")
+		return nil, errors.New("Invalid PE File Format.")
 	}
 	// get symbol string table
 	sr.Seek(int64(f.FileHeader.PointerToSymbolTable+18*f.FileHeader.NumberOfSymbols), os.SEEK_SET)
@@ -215,7 +216,7 @@ func (f *File) Section(name string) *Section {
 	return nil
 }
 
-func (f *File) DWARF() (*dwarf.Data, os.Error) {
+func (f *File) DWARF() (*dwarf.Data, error) {
 	// There are many other DWARF sections, but these
 	// are the required ones, and the debug/dwarf package
 	// does not use the others, so don't bother loading them.
@@ -242,7 +243,7 @@ func (f *File) DWARF() (*dwarf.Data, os.Error) {
 // referred to by the binary f that are expected to be
 // satisfied by other libraries at dynamic load time.
 // It does not return weak symbols.
-func (f *File) ImportedSymbols() ([]string, os.Error) {
+func (f *File) ImportedSymbols() ([]string, error) {
 	pe64 := f.Machine == IMAGE_FILE_MACHINE_AMD64
 	ds := f.Section(".idata")
 	if ds == nil {
@@ -308,7 +309,7 @@ func (f *File) ImportedSymbols() ([]string, os.Error) {
 // ImportedLibraries returns the names of all libraries
 // referred to by the binary f that are expected to be
 // linked with the binary at dynamic link time.
-func (f *File) ImportedLibraries() ([]string, os.Error) {
+func (f *File) ImportedLibraries() ([]string, error) {
 	// TODO
 	// cgo -dynimport don't use this for windows PE, so just return.
 	return nil, nil